Device And Method For Controlling Engines

专利摘要:
The engine can switch the combustion mode between homogeneous combustion and stratified combustion and is controlled according to the load of the engine. At the time of performing the homogeneous combustion, the intake pressure, which is a parameter related to the intake amount, is used as a value representing the engine load. At the time of performing stratified combustion, a value corresponding to the intake pressure when homogeneous combustion is executed according to the operation amount of the accelerator pedal is calculated as the virtual intake pressure, and the next pressure is used as a value representing the engine load. In both combustion schemes, the intake pressure, a common parameter, is used as a value representing the engine load, controlling the engine, thereby simplifying the matching between engine output torque characteristics in the two combustion schemes.
公开号:KR20020005573A
申请号:KR1020017008750
申请日:2000-01-11
公开日:2002-01-17
发明作者:미즈노히로유키；다카기노보루；후와나오히데
申请人:사이토 아키히코；도요타지도샤가부시키가이샤；
IPC主号:

专利说明:

Device And Method For Controlling Engines
[2] In a typical vehicle engine, air sucked into a combustion chamber via an intake passage and fuel injected from a fuel injection valve are mixed to form an air-fuel mixer. The engine gains driving power by burning the air-fuel mixture in the combustion chamber. A throttle valve is provided in the intake passage for adjusting the amount of air sucked into the combustion chamber. By adjusting the opening of the throttle valve to adjust the amount of air sucked into the combustion chamber, the amount of air-fuel mixer charged in the combustion chamber is changed, thereby adjusting the output of the engine.
[3] In recent years, in order to improve fuel economy and at the same time obtain sufficient engine output, an engine of a type in which the combustion mode is switched in accordance with the operating state of the engine has been proposed and put into practical use. Such an engine is disclosed, for example, in Japanese Patent Laid-Open No. 5-288098.
[4] The engine disclosed in this publication has a fuel injection valve for directly injecting fuel into a combustion chamber. At high revolutions of the engine or at high loads, combustion occurs with the fuel uniformly mixed with the air so that sufficient engine output is produced. This type of combustion is called homogeneous combustion. In order to perform homogeneous combustion, fuel is injected into the combustion chamber at the intake stroke of the engine. The injected fuel is uniformly mixed with air in the combustion chamber and a homogeneous mixture of air and fuel is ignited by the spark plug.
[5] On the other hand, during low rotation or low load of the engine, stratified combustion is performed to improve fuel efficiency. In stratified combustion, the fuel concentration around the spark plug is increased to improve ignition, and combustion is performed while the average air-fuel ratio of the mixer in the combustion chamber is larger than the theoretical air-fuel ratio. In order to perform stratified combustion, fuel is injected into the combustion chamber during the compression stroke of the engine. The injected fuel strikes the dents provided on the apex surface of the piston and collects around the spark plug. The mixer of the collected fuel and air in the combustion chamber is ignited by a spark plug.
[6] In stratified combustion, the opening of the throttle valve is greater than in homogeneous combustion. As a result, the pumping loss is reduced.
[7] By switching the combustion mode of the engine between homogeneous combustion and stratified combustion according to the operating state of the engine in the manner as described above, fuel economy is improved and sufficient engine output is obtained.
[8] Typically, the engine is controlled according to the load. One example of the control according to the engine load is fuel injection amount control. In the engine in which the combustion mode is switched, a parameter representing the intake air amount, for example, the intake air amount itself or the intake pressure is used as a value representing the engine load during homogeneous combustion. According to the value of the parameter, the fuel injection amount is controlled.
[9] In stratified combustion, the throttle opening is greater than the throttle opening in homogeneous combustion. If the fuel injection amount is controlled using a parameter indicating the intake air amount in stratified combustion, the fuel injection amount is not appropriate for the engine load. Therefore, in stratified combustion, the engine load is represented using the operation amount of the accelerator pedal, and the fuel injection amount is controlled according to the position of the accelerator pedal.
[10] As is apparent from the above description, the fuel injection amount control in accordance with the engine load is appropriately executed by switching the value used to represent the engine load in accordance with the combustion method of the engine.
[11] The value used to represent the engine load depends on the combustion scheme of the engine, which means that the control carried out according to the engine load during homogeneous combustion and stratified combustion is independent of each other.
[12] Control performed according to engine load generally affects the output torque of the engine. However, it is difficult to match the engine output torque characteristics between the combustion schemes if the control performed according to the engine load during homogeneous combustion and stratified combustion is mutually independent. In particular, the fuel injection amount control has a significant influence on the engine output torque including the response characteristic in the transient state of the engine output torque characteristic. Therefore, it is difficult to match the engine output torque characteristics between homogeneous combustion and stratified combustion.
[1] The present invention relates to an engine of a type of switching the combustion method, and more particularly to a control device and a control method for controlling the engine in accordance with the load applied to the engine.
[17] 1 is a cross-sectional view showing an engine according to a first embodiment of the present invention.
[18] FIG. 2 is a block diagram showing an electrical configuration of a control device mounted to the engine of FIG. 1. FIG.
[19] 3 is a flowchart showing a procedure for calculating various control values of the engine.
[20] 4 is a map for reference when calculating the intake air temperature correction coefficient.
[21] 5 is a map for referring to the calculation of the atmospheric pressure correction coefficient.
[22] 6 is a map for reference when calculating a water temperature correction coefficient.
[23] 7 shows the change in the target throttle opening during homogeneous combustion, the actual throttle opening, the predicted intake pressure and the basic fuel injection amount, and the virtual throttle opening during stratified combustion, and the change of the accelerator pedal depressed amount. Time chart showing the transition of the basic fuel injection amount.
[24] 8 is a flowchart showing a procedure of calculating the predicted intake pressure.
[25] 9 is a flowchart showing a procedure for calculating the predicted intake pressure.
[26] 10 is a time chart showing the transition of the throttle opening after the phase progress compensation and the actual throttle opening with respect to the target throttle opening.
[27] Fig. 11 is a map for reference when calculating the amount of target progression angle.
[28] Fig. 12 is a map for referring to the calculation of the intake pressure at the time when the valve timing of the intake valve is the maximum traveling angle.
[29] FIG. 13 is a map to refer to when the intake pressure at normal time when the valve timing of the intake valve is the maximum delay angle;
[30] FIG. 14 is a time chart showing the transitions of the correction intake pressure PMTA, the gradual change value PMSM, the filter output PMSM1S _i , and the actual intake pressure PMr.
[31] 15 is a flowchart showing a procedure of calculating the virtual intake pressure.
[32] Fig. 16 is a map for referring to the calculation of the atmospheric pressure correction coefficient.
[33] 17 is a flowchart showing a procedure for calculating the final fuel injection amount according to the second embodiment.
[34] 18 is a time chart showing the transition of the predicted intake pressure, the virtual intake pressure, the fuel injection amount correction coefficient, and the engine torque when the homogeneous combustion is converted to stratified combustion.
[35] Fig. 19 is a time chart showing the transition of the predicted intake pressure, the virtual intake pressure, the fuel injection amount correction coefficient, and the engine torque when the homogeneous combustion is converted to stratified combustion.
[36] 20 is a flowchart showing a procedure for calculating a target ignition timing according to the second embodiment.
[37] Fig. 21 is a time chart showing the transition of predicted intake pressure, virtual intake pressure, ignition timing delay angle correction amount and engine torque when stratified combustion is converted to homogeneous combustion.
[38] FIG. 22 is a time chart showing the transitions of predicted intake pressure, virtual intake pressure, throttle opening degree correction coefficient, and engine torque when stratified combustion is converted to homogeneous combustion; FIG.
[39] Fig. 23 is a flowchart showing a procedure for calculating a target throttle opening degree according to the second embodiment.
[40] 24 is a flowchart showing a procedure of a delay process at the time of switching from stratified combustion to homogeneous combustion according to the second embodiment.
[41] FIG. 25 is a graph showing the changes in the predicted intake pressure, the virtual intake pressure, and the engine torque according to the change of the engine load during stratified combustion and homogeneous combustion; FIG.
[42] FIG. 26 is a graph showing the changes in the predicted intake pressure, the virtual intake pressure, and the engine torque according to the change of the engine load during stratified combustion and homogeneous combustion; FIG.
[43] 27 is a flowchart showing a procedure for calculating the final fuel injection amount according to the third embodiment.
[44] Fig. 28 is a flowchart showing a procedure for calculating a learning value according to the third embodiment.
[45] 29 is a flowchart showing a processing sequence of the homogeneous combustion counter according to the third embodiment.
[46] 30 is a flowchart showing a procedure for calculating a target throttle opening degree according to the fourth embodiment.
[47] Fig. 31 is a flowchart showing a procedure for calculating a learning value according to the fourth embodiment.
[48] Fig. 32 is a graph showing the trends of the predicted intake pressure, the virtual intake pressure, the target throttle opening degree, and the engine torque according to the change of the engine load during stratified combustion and homogeneous combustion.
[49] Fig. 33 is a graph showing the transitions of the predicted intake pressure, the virtual intake pressure, the target throttle opening degree, and the engine torque according to the engine load during stratified combustion and homogeneous combustion.
[50] 34 is a flowchart showing a procedure of fuel cutoff control according to the fifth embodiment.
[51] 35 is a flowchart showing a procedure of air conditioner cutoff control according to the sixth embodiment.
[52] 36 is a flowchart showing a procedure of air conditioner shutoff control according to the seventh embodiment.
[53] 37 is a flowchart showing a calculation procedure of a target ignition timing according to the seventh embodiment.
[13] SUMMARY OF THE INVENTION The present invention has been made in view of this point, and an object of the present invention is to provide an engine control apparatus and a control method which can easily match engine output torque characteristics between homogeneous combustion and stratified combustion during engine control depending on engine load. To provide.
[14] In order to achieve the above object, the present invention provides a control apparatus of an engine that obtains power by burning a mixture of air and fuel in a combustion chamber. The engine has an accelerator pedal and a throttle valve for adjusting the intake air amount into the combustion chamber. The engine can switch the combustion mode between homogeneous combustion and stratified combustion. The control device has control means for controlling the engine in accordance with the load acting on the engine. When the homogeneous combustion is executed, the control means uses a parameter representing the intake air amount as a value representing the engine load. The control apparatus further has calculation means for calculating, as a virtual parameter, a value corresponding to the parameter when homogeneous combustion is executed by the operation amount of the accelerator pedal when stratified combustion is executed. When stratified combustion is executed, the control means uses the virtual parameter as a value representing engine load.
[15] The present invention also provides a method of controlling an engine that is powered by burning a mixture of air and fuel in a combustion chamber. The engine has an accelerator pedal and a throttle valve for adjusting the intake air amount into the combustion chamber. The engine can switch the combustion mode between homogeneous combustion and stratified combustion. The control method includes the steps of controlling the engine in accordance with a load acting on the engine, using a parameter representing an intake amount when the homogeneous combustion is executed as a value representing the engine load, and an operation amount of the accelerator pedal when stratified combustion is executed. Calculating as a virtual parameter a value corresponding to a parameter when homogeneous combustion is performed by using the same, and using the virtual parameter as a value representing an engine load when stratified combustion is executed.
[16] In any combustion system of homogeneous combustion or stratified combustion, a common parameter representing the intake air amount is used as a value representing the engine load at the time of engine control. This relates engine control according to engine load in homogeneous combustion to engine control in stratified combustion, thus ensuring easy matching of engine output torque between combustion schemes.
[54] (First embodiment)
[55] Hereinafter, a first embodiment in which the present invention is applied to a four-cylinder in-line vehicle gasoline engine will be described with reference to FIGS. 1 to 16.
[56] As shown in FIG. 1, the engine 11 has a cylinder block 11a having four cylinders (only one is shown). The piston 12 provided corresponding to each cylinder reciprocates in the cylinder block 11a. Each piston 12 is connected to the crankshaft or output shaft 14 via a connecting rod 13. The reciprocating motion of the piston 12 is converted into the rotational motion of the crankshaft 14 by the connecting rod 13. A recess 12a for performing stratified combustion is formed in the apex surface of the piston 12.
[57] The signal rotor 14a is attached to one end of the crankshaft 14. On the outer circumferential surface of the signal rotor 14a a plurality of projections 14b are provided at equal angular intervals around the axis of the crankshaft 14. The crank position sensor 14c is provided to face the outer circumferential surface of the signal rotor 14a. As the crankshaft 14 rotates, each projection 14b on the signal rotor 14a sequentially passes through a position opposite the crank position sensor 14c. The crank position sensor 14c outputs a pulsed detection signal in accordance with the passage of the protrusion 14b.
[58] The cylinder block 11a is equipped with the coolant temperature sensor 11b which detects the temperature THW of the coolant which flows in the engine 11 as the temperature of the engine 11.
[59] The cylinder head 15 is mounted on the upper end of the cylinder block 11a. Combustion chamber 16 is formed between cylinder head 15 and each piston 12. The intake port 17 and the exhaust port 18 provided in the cylinder head 15 are connected to each combustion chamber 16. The intake valve 19 is provided corresponding to the intake port 17. Similarly, an exhaust valve 20 is provided corresponding to the exhaust port 20.
[60] As shown in FIG. 1, the intake cam shaft 21 for driving the intake valve 19 is rotatably supported on the cylinder head 15. In addition, an exhaust cam shaft 22 for driving the exhaust valve 20 is rotatably supported on the cylinder head 15. The intake and exhaust camshafts 21 and 22 are connected to the crankshaft 14 via drive and transmission mechanisms including timing belts and gears (not shown). When the intake cam shaft 21 is rotated by the crankshaft 14, the intake valve 19 is driven in such a manner as to selectively connect and disconnect the intake port 17 with respect to the combustion chamber 16. When the exhaust cam shaft 22 is rotated by the crankshaft 14, the exhaust valve 20 is driven to selectively connect and disconnect the exhaust port 18 with respect to the combustion chamber 16.
[61] Transmission of rotation from the crankshaft 14 to the intake camshaft 21 is performed via the valve timing variable mechanism 27 provided on the intake camshaft 21. The valve timing variable mechanism 27 changes the valve timing of the intake valve 19 by changing the rotational phase of the intake cam shaft 21 with respect to the crankshaft 14. The valve timing variable mechanism 27 is driven by oil supplied via an oil control valve (OCV) 27a. The valve timing of the intake valve 19 is adjusted by controlling the oil pressure for operating the valve timing variable mechanism 27 by controlling the OCV 27a. Adjustment of the valve timing keeps the valve timing of the intake valve 19 at an optimum state, which improves engine power and reduces fuel consumption.
[62] The cam position sensor 21b is provided on the cylinder head 15 to face the outer circumferential surface of one end of the intake cam shaft 21. One or a plurality (two in FIG. 1) projections 21a are provided on the outer circumferential surface of one end of the intake cam shaft 21. When the intake cam shaft 21 rotates, the projection 21a passes through a position opposite the cam position sensor 21b. The cam position sensor 21b outputs a pulsed detection signal according to the passage of the protrusion 21a.
[63] The intake manifold 30 is connected to the intake port 17. The exhaust manifold 31 is connected to the exhaust port 18. The intake manifold 30 and the intake port 17 constitute an intake passage 32, and the exhaust manifold 31 and the exhaust port 18 constitute an exhaust passage 33. The throttle valve 23 is disposed in the intake passage 32. The throttle valve 23 is driven by a throttle motor 24 composed of a DC motor to adjust the opening amount of the intake passage 32. The opening degree of the throttle valve 23 is detected by the throttle position sensor 44.
[64] The throttle motor 24 is controlled based on the amount of depression of the accelerator pedal 25 provided in the passenger compartment of the vehicle. When the driver of the vehicle depresses the accelerator pedal 25, the amount of depression of the accelerator pedal 25 is detected by the accelerator pedal position sensor 26, and the throttle motor 24 is controlled based on the detection result. The throttle motor 24 adjusts the opening degree of the throttle valve 23. The amount of air supplied from the intake passage 32 into the combustion chamber 16 is adjusted in accordance with the opening degree of the throttle valve 23.
[65] On the downstream side of the throttle valve 23, a vacuum sensor 36 for detecting the internal pressure of the intake passage 32 is provided. The vacuum sensor 36 outputs a detection signal corresponding to the internal pressure of the intake passage 32. On the upstream side of the throttle valve 23, an air temperature sensor 37 for detecting the temperature of the air passing through the intake passage 32 is provided. The air temperature sensor 37 outputs a detection signal corresponding to the detected air temperature (intake temperature) THA.
[66] As shown in FIG. 1, a fuel injection valve 40 for directly injecting fuel into the combustion chamber 16 is provided in the cylinder head 15 corresponding to each combustion chamber 16. Spark plugs 41 for igniting a mixture of air and fuel in the combustion chamber are provided corresponding to each combustion chamber 16. The timing at which the spark plug 41 performs ignition is adjusted by the igniter 41a provided above the spark plug 41.
[67] The fuel injected from the fuel injection valve 4 into the combustion chamber 16 mixes with the air sucked from the intake passage 32 into the combustion chamber 16, so that a mixture of air and fuel is formed in the fuel chamber 16. The mixer in the combustion chamber 16 is ignited and combusted by the spark plug 41, and the gas generated by the combustion is sent to the exhaust passage 33 as exhaust gas.
[68] A portion of the intake passage 32 downstream of the throttle valve 23 is connected to the exhaust passage 33 via an exhaust gas recirculation passage (EGR passage) 42. An EGR valve 43 having a step motor 43a is disposed in the EGR passage 42. The opening degree of the EGR valve 43 is adjusted by the step motor 43a. By adjusting the opening degree of the EGR valve 43, the exhaust amount (EGR amount) recycled from the exhaust passage 33 to the intake passage 32 is adjusted. By the exhaust gas being recycled to the intake passage 32, the temperature of the combustion chamber 16 is lowered, which suppresses the generation of nitrogen oxides (NOx) and thereby reduces the exhaust emission.
[69] The electrical configuration of the control device of the engine 11 will be described with reference to FIG. 2. The control apparatus has an electronic control unit (hereinafter referred to as "ECU") 92 which performs engine control such as fuel injection amount control, fuel injection timing control, ignition timing control, throttle opening degree control, and EGR control. . The ECU 92 is configured as a logic arithmetic circuit including a ROM 93, a CPU 94, a RAM 95, a backup RAM 96, and the like.
[70] The ROM 93 stores various control programs or maps referred to when the various control programs are executed. The CPU 94 executes arithmetic processing based on various control programs and maps stored in the ROM 93. The RAM 95 temporarily stores the calculation result in the CPU 94 or the data input from various sensors. The backup RAM 96 is a nonvolatile memory that stores data to be stored when the engine 11 is stopped. The ROM 93, the CPU 94, the RAM 95, and the backup RAM 96 are connected to each other by the bus 97, and are connected to the external input circuit 98 and the external output circuit 99.
[71] The external input circuit 98 includes a coolant temperature sensor 11b, a crank position sensor 14c, a cam position sensor 21b, an accelerator pedal position sensor 26, a vacuum sensor 36, an air temperature sensor 37, The throttle position sensor 44 and the like are connected. The throttle motor 24, the OCV 27a, the fuel injection valve 40, the igniter 41a, the EGR valve 43, and the like are connected to the external output circuit 99.
[72] The ECU 92 switches the combustion mode between stratified combustion and homogeneous combustion in accordance with the operating state of the engine 11. The ECU 92 sets the combustion scheme to homogeneous combustion when the engine 11 is in a high rotation or high load state. When the engine 11 is in a low rotation or low load state, the ECU 92 sets the combustion system to stratified combustion. In the high rotational or high load state of the engine, since homogeneous combustion is carried out, the air-fuel ratio of the mixer is relatively small, and thus the engine output is high. In the low rotation or low load state of the engine, stratified combustion is performed, so that the air-fuel ratio of the mixer is relatively large, and thus fuel economy is improved.
[73] When homogeneous combustion is executed, the ECU 92 injects fuel from the fuel injection valve 40 during the intake stroke of the engine 11. At this time, the air-fuel ratio of the mixer in the combustion chamber 16 is equal to or larger than the theoretical air-fuel ratio. The ECU 92 controls the drive of the throttle motor 24 such that the actual throttle opening is close to the target throttle opening based on the accelerator pedal depressed amount, and the ignition timing, the EGR amount, and the like are suitable for homogeneous combustion. The igniter 41a and the EGR valve 43 and the like are controlled as possible.
[74] When stratified combustion is executed, the ECU 92 injects fuel from the fuel injection valve 40 during the compression stroke of the engine 11. At this time, the air-fuel ratio of the mixer in the combustion chamber 16 becomes larger than the air-fuel ratio at the time of homogeneous combustion. The ECU 92 controls the drive of the throttle motor 24 so that the actual throttle opening is close to the target throttle opening based on the basic fuel injection amount calculated from the accelerator pedal depressed amount described below, and the ignition timing, EGR The igniter 41a and the EGR valve 43 and the like are controlled so that the amount and the like become a value suitable for stratified combustion.
[75] When stratified combustion is executed, fuel injected from the fuel injection valve 40 enters the recessed portion 12a (see FIG. 1) provided at the apex of the piston 12, and the spark plug is moved by the movement of the piston 12. 41 are gathered around. Therefore, even if the average air-fuel ratio of the mixer in the combustion chamber 16 is larger than during homogeneous combustion, the air-fuel ratio of the mixer around the spark plug 41 is a value suitable for ignition. As a result, the mixer is well ignited. In order to make the average air-fuel ratio of the entire air-fuel mixture in the combustion chamber 16 larger than in the homogeneous combustion, the throttle opening degree is relatively large and the intake amount is increased. Therefore, during stratified combustion, the pumping loss of the engine 11 is reduced.
[76] In the engine 11, various controls such as fuel injection amount control, ignition timing control, throttle opening degree control, and EGR control are executed through the ECU 92. For example, in the fuel injection amount control during homogeneous combustion, a parameter indicating the intake pressure or the intake amount is used as a value representing the engine load, and the fuel injection amount is controlled according to the intake pressure.
[77] On the other hand, in stratified combustion, the throttle opening degree when the amount of depression of the accelerator pedal 25 has a predetermined value is greater than in homogeneous combustion, and the intake pressure is higher than in homogeneous combustion. Therefore, in stratified combustion, the fuel injection amount is not suitable for the engine load, even though the fuel injection amount control is executed based on the intake pressure. Thus, the amount of depression of the accelerator pedal 25 is used as a value indicating the engine load during stratified combustion, and the fuel injection amount is controlled in accordance with the amount of depression of the accelerator pedal.
[78] As described above, the fuel injection amount control in accordance with the engine load is appropriately performed by switching the parameter used as the value representing the engine load in accordance with the combustion method of the engine. However, if the parameter used as the value representing the engine load differs depending on the combustion method of the engine, the control executed in accordance with the engine load during homogeneous combustion and stratified combustion becomes independent of each other. This makes it difficult to match engine output torque characteristics between the combustion regimes.
[79] According to the present embodiment, the intake pressure when homogeneous combustion is executed is calculated as the virtual intake pressure by the accelerator pedal depression amount in stratified combustion, and the engine intake rate when the virtual intake pressure executes various controls according to the engine load is calculated. It is used as a value to indicate. Since the intake pressure is used as a value representing the engine load in both stratified combustion and homogeneous combustion, the control performed according to the engine load in homogeneous combustion corresponds to the control in stratified combustion. This simplifies the matching of engine output torque characteristics between the combustion regimes.
[80] With reference to FIG. 3, the procedure of calculating various control values used for the control of the engine 11 is demonstrated. 3 shows a control value calculation routine for calculating various control values of the engine 11. The control value calculation routine is executed in the interruption which occurs every predetermined time interval (for example, 8 ms) via the ECU 92.
[81] In the process of step S101, the ECU 92 obtains an accelerator pedal depressed amount ACCP based on the detection signal from the accelerator pedal position sensor 26, and is known based on the accelerator pedal depressed amount ACCP. By referring to the map, the target throttle opening degree TAt at the time of homogeneous combustion is calculated. Next, in the process of step S102, the ECU 92 determines whether stratified combustion is currently being executed. If it is determined that stratified combustion is not currently performed, that is, it is determined that homogeneous combustion is being executed, the flow proceeds to step S104.
[82] In the homogeneous combustion, the ECU 92 causes the throttle motor so that the actual throttle opening TA obtained based on the detection signal from the throttle position sensor 44 is close to the target throttle opening TAt obtained previously. 24). In this homogeneous combustion, the ECU 92 calculates the predicted intake pressure PMFWD in the process of step S104. The predicted intake pressure PMFWD is a value for predicting the intake pressure when the intake valve 19 is closed and is a parameter representing the intake amount.
[83] When the intake pressure is used for fuel injection amount control and ignition timing control as a value representing the engine load, it is suitable to use the intake pressure at the time when the intake amount of the engine 11 is determined or near the closing time of the intake valve 19. Do. In this case, the intake pressure near the closing time of the intake valve 19 is actually measured, and the driving of the fuel injection valve 40 and the igniter 41a is controlled based on the fuel injection amount and the ignition timing calculated from the measured value. do. However, when the fuel injection valve 40 and the igniter 41a are controlled based on the control value, a state in which the optimum time for performing the control has already elapsed occurs.
[84] Therefore, in the process of step S104, the predicted intake pressure PMFWD at the closing time of the intake valve 19 is calculated before the intake valve 19 is closed, and the predicted intake pressure PMFWD represents the engine load. By using as a value, the control values for the above-mentioned various controls are calculated. In the processing of step S104, the predicted intake pressure PMFWD is calculated based on the actual intake pressure PMr, the actual throttle opening degree TAr, the engine speed NE, and the like. The actual intake pressure PMr is obtained based on the detection signal from the vacuum sensor 36, and the engine speed NE is obtained based on the detection signal from the crank position sensor 14c.
[85] If it is determined in the processing of step S102 that stratified combustion is currently being executed, the flow proceeds to step S103. In the process of step S103, the ECU 92 calculates the virtual intake pressure PMv. The virtual intake pressure PMv is a value corresponding to the predicted intake pressure PMFWD when the homogeneous combustion is executed by the accelerator pedal press amount ACCP during stratified combustion, and the target throttle opening degree TAt during the homogeneous combustion. It is an imaginary value calculated based on. In the processing of step S103, the actual throttle opening degree when the homogeneous combustion is executed by the current (at stratified combustion) accelerator pedal depressed amount ACCP is based on the target throttle opening degree TAt at the homogeneous combustion. It is calculated as the virtual throttle opening degree Tav. Moreover, the actual intake pressure PMv is calculated based on the virtual throttle opening degree TAv and the like.
[86] The process of step S103 or step S104 is executed in the manner described above to calculate the virtual intake pressure PMv or the predicted intake pressure PMFWD, and then proceeds to the next step S105. In the process of step S105, the ECU 92 uses the virtual intake pressure PMv or the predicted intake pressure PMFWD as the intake pressure PM, and uses the basic fuel injection amount Q _bse from Equation 1 _below . Calculate. That is, the basic fuel injection amount Q _bse is the intake pressure PM, the volume efficiency ηv calculated with reference to the map based on the intake pressure PM and the engine speed NE, and the intake temperature correction coefficient. It is calculated by multiplying (K _tha ) and the constant (K).
[87]
[88] The intake air temperature correction coefficient K _tha is a correction coefficient for compensating for the change in the volume efficiency ηv caused by the change in the intake air temperature THA. The ECU 92 obtains the intake air temperature THA based on the detection signal from the air temperature sensor 37, and calculates the intake air temperature correction coefficient K _tha based on the intake air temperature THA with reference to the map of FIG. 4. Calculate. As the intake air temperature THA increases, the intake air temperature correction coefficient K _tha decreases and approaches 1.0. Therefore, as the intake temperature THA is lowered, the basic fuel injection amount Q _bse after correction becomes larger.
[89] 7 (a) to 7 (e), how the target throttle opening degree TAt, the actual throttle opening degree TAr, the predicted intake pressure PMFWD, and the basic fuel injection amount Q _bse change during homogeneous combustion. And how the virtual throttle opening degree TAv, the virtual intake pressure PMv, and the basic fuel injection amount Q _bse change with respect to the change of the predicted acceleration pedal depression amount ACCP during stratified combustion.
[90] The graph (a) of FIG. 7 shows an example of the change of the acceleration pedal depression amount ACCP. When the acceleration pedal depression amount ACCP changes as shown in the graph (a), the target throttle during homogeneous combustion The opening (TAt) changes as indicated by the dashed dashed line in the graphs (b) and (d). For this trend of target throttle opening TAt, during homogeneous combustion, the actual throttle opening TAr changes with a predicted response delay as indicated by the thin solid line in graph (b). This response delay is provided to prevent excessive changes in the actual throttle opening TA or so-called overshoot with respect to the change in the target throttle opening TA. With respect to the actual throttle opening degree TAr, the predicted intake pressure PMFWD during homogeneous combustion changes with a predetermined response delay as indicated by the thick solid line in the graph (b). Furthermore, for the trend of the predicted intake pressure PMFWD, the basic fuel injection amount during homogeneous combustion changes as shown in the graph (c).
[91] With respect to the target throttle opening TAt at the homogeneous combustion shown in the graph (d), the virtual throttle opening TAv at the stratified combustion is a predetermined response delay as shown by the thin solid line in the graph (d). To change. The trend of the transition of the virtual throttle opening (TAv) during stratified combustion becomes the same as the trend of the trend of the actual throttle opening (TAr) of homogeneous combustion as shown in the graph (b). That is, the ECU 92 calculates the virtual throttle opening degree TAv based on the target throttle opening degree TAt in order to change the virtual throttle opening degree TAv in the above-described manner.
[92] As for the transition of the virtual throttle opening degree TAv, the virtual intake pressure PMv at the time of stratified combustion changes with a predetermined response delay as shown by the solid line of the graph (d). The trend of the transition of the virtual intake pressure PMv during stratified combustion becomes the same as the trend of the trend of the predicted intake pressure PMFWD during homogeneous combustion, as shown in the graph (b). That is, the ECU 92 calculates the virtual intake pressure PMv based on the virtual throttle opening degree TAv and the like in order to change the virtual intake pressure PMv in the above-described manner.
[93] In addition, with respect to the change of the virtual intake pressure PMv, the basic fuel injection quantity Q _bse at the time of stratified combustion changes as shown to the graph (e). Since the trend of the basic fuel injection amount Q _bse at the time of stratified combustion is equal to the virtual intake pressure PMv and the predicted intake pressure PMFWD, the basic fuel injection amount at the time of homogeneous combustion shown in the graph (c) ( Q _bse ) is the same as the trend.
[94] The control value calculation routine of FIG. 3 will be described again with reference. After the basic fuel injection amount Q _bse is calculated in the process of step S105, the ECU 92 executes the process of step S106. In the processing of step S106, the ECU 92 is based on the engine 11, such as ignition timing control, throttle opening degree control, and EGR control, based on the predicted intake pressure PMFWD or the basic fuel injection amount Q _bse . The control value for various operation control is calculated. As the engine 11 is controlled based on the various control values, the engine 11 is controlled according to the engine load.
[95] Specifically, during homogeneous combustion, the ECU 92 calculates a target ignition timing, target EGR amount, etc. during homogeneous combustion by referring to a map based on the predicted intake pressure PMFWD and the engine speed NE. During stratified combustion, the ECU 92 calculates a target ignition timing, target EGR amount, target throttle opening degree, etc. during stratified combustion by referring to a map based on the basic fuel injection amount Q _bse and the engine speed NE. do.
[96] As the target ignition timing, target EGR amount and target throttle opening degree are calculated, the ECU 92 controls the igniter 41a in a separate routine so that the ignition timing becomes the target ignition timing, and the actual EGR amount and the actual throttle opening degree The EGR valve 43 and the throttle motor 24 are controlled so that TAr approaches the target EGR amount and the target throttle opening degree.
[97] The basic fuel injection amount Q _bse is calculated using the same parameter or intake pressure (virtual intake pressure PMv or predicted intake pressure PMFWD) in any combustion system of stratified combustion and homogeneous combustion. Therefore, various controls such as fuel injection amount control, ignition timing control, and EGR control, which are controlled according to engine load using the basic fuel injection amount Q _bse during stratified combustion, use the predicted intake pressure PMFWD during homogeneous combustion. And control such as fuel injection amount control, ignition timing control, and EGR control, which are controlled according to engine load. This enables easy matching of engine output torque characteristics between homogeneous combustion and stratified combustion.
[98] In the process of step S107, the ECU 92 calculates a mode correction coefficient K _mode . The mode correction coefficient K _mode is a correction coefficient for compensating for the difference in required fuel injection amount resulting from the difference in combustion efficiency between homogeneous combustion and stratified combustion. The ECU 92 calculates a mode correction coefficient K _mode according to the current combustion method. The mode correction coefficient K _mode is set to 1.0 when the combustion efficiency is lower than in stratified combustion. Since the pumping or cooling losses are greater in homogeneous combustion than in stratified combustion, the combustion efficiency is lower in homogeneous combustion than in stratified combustion.
[99] In stratified combustion with higher combustion efficiency, the ECU 92 calculates the final mode correction coefficient K _mode by multiplying the atmospheric pressure correction coefficient K _pa 2 by 0.8, which is a basic mode correction coefficient, for example. The pumping loss of the engine 11 changes with atmospheric pressure PA, and when the atmospheric pressure PA becomes low, the difference in pumping loss between homogeneous combustion and stratified combustion becomes small. Therefore, the ECU 92 calculates the atmospheric pressure correction coefficient K _pa 2 by referring to the map of FIG. 5 based on the atmospheric pressure PA. Atmospheric pressure PA is obtained based on the detection signal from the vacuum sensor 36 when the engine 11 starts. The atmospheric pressure (PA) The atmospheric pressure correction coefficient is lower (K _pa 2) is becomes larger, the atmospheric pressure (PA) The atmospheric pressure correction coefficient is large (K _pa 2) is close to 1.0. By multiplying the basic mode correction coefficient K _mode 0.8 by the atmospheric pressure correction coefficient K _pa 2, the final mode correction coefficient K _mode is set to a large value, for example, 0.85 when the atmospheric pressure PA is low. .
[100] When calculating the mode correction coefficient K _mode in step S107 in this manner, the ECU 92 has a coolant temperature correction coefficient K _thw and a mode correction coefficient K _mode at the basic fuel injection amount Q _bse . After calculating the final fuel injection amount Q _fin by multiplying, the control value calculation routine is temporarily finished. The ECU 92 then controls the driving of the fuel injection valve 40 in a separate routine to inject a quantity of fuel corresponding to the final fuel injection amount Q _fin into the combustion chamber 16. The coolant temperature correction coefficient K _thw is a compensation coefficient for compensating for changes in combustion efficiency such as frictional losses resulting from changes in coolant temperature THW. The ECU 92 obtains the coolant temperature THW based on the detection signal from the coolant temperature sensor 11b, and refers to the map of FIG. 6 based on the coolant temperature THW to coolant temperature correction coefficient K _thw . To calculate. As the coolant temperature THW becomes high, the coolant temperature correction coefficient K _thw becomes small and approaches 1.0. Therefore, as the coolant temperature THW is lowered, the final fuel injection amount Q _fin is further increased.
[101] As the basic fuel injection amount Q _bse is corrected by the mode correction coefficient K _{mode in the} above-described manner, the final fuel injection amount Q _fin is adjusted according to the difference in combustion efficiency in each combustion method. In stratified combustion with high combustion efficiency, the final fuel injection amount Q _fin is reduced more than in homogeneous combustion. Since fuel injection control is executed based on the final fuel injection amount Q _fin calculated in consideration of the difference in combustion efficiency in each combustion method, the accuracy of engine output torque control based on fuel injection control is This can be improved when the scheme is executed.
[102] In addition, the pumping loss of the engine 11 differs between stratified combustion and homogeneous combustion, and the difference in pumping loss between the combustion schemes varies with atmospheric pressure PA. However, since the mode correction coefficient K _mode used to calculate the final fuel injection amount Q _fin is corrected by the atmospheric pressure correction coefficient K _pa 2, the change of the pumping loss according to the atmospheric pressure PA is changed. The reduction in the accuracy of the resulting engine output torque control is prevented.
[103] The processing of step S104 of the control value calculation routine will be described in detail with reference to FIGS. 8 and 9. 8 and 9 are flowcharts showing a predicted intake pressure calculation routine for calculating the predicted intake pressure PMFWD at the time of homogeneous combustion. The predicted intake pressure calculation routine shows details of the processing in step S104 of FIG.
[104] As shown in FIG. 8, the ECU 92 calculates the actual throttle opening degree TAr based on the detection signal from the throttle position sensor 44. Next, in the process of step S202, the ECU 92 drives the throttle motor 24 by driving the throttle motor 24 based on the actual throttle opening degree TAr and the target throttle opening degree TAt during homogeneous combustion. Control the degree of opening).
[105] When the throttle motor 24 is driven, the ECU 92 calculates a compensation value TAh for compensating for the control of the throttle motor 24 based on Equation 2 below.
[106]
[107] In Equation 2, dTAr / dt is a value obtained by differentiating the actual throttle opening degree TAr with respect to time t. The compensation value TAh calculated based on Equation 2 is a value closer to the target throttle opening TAt than the actual throttle opening TAr while the target throttle opening TAt is changed.
[108] The ECU 92 calculates the difference e2 between the target throttle opening degree TAt and the compensation value TAh by the following equation (3). The ECU 92 controls the driving of the throttle motor 24 such that the difference e2 approaches zero, that is, the compensation value TAh approaches the target throttle opening degree TAt.
[109]
[110] 10 shows how the compensation value TAh and the actual throttle opening TAr change as the target throttle opening TAt changes over time.
[111] When the target throttle opening degree TAt changes as indicated by the dashed-dotted line in Fig. 10, the compensation value TAh changes near the target throttle opening degree TAt as indicated by the thin solid line. By controlling the throttle motor 24 such that the difference e2 between the compensation value TAh and the target throttle opening TAt approaches zero, the actual throttle opening TA is determined by the target throttle opening TAt. The change is made with a predetermined response delay as indicated by the bold solid line for the change. By providing this response delay to the actual throttle opening TAr, overshoot of the actual throttle opening TAr is prevented.
[112] After the throttle opening degree control is executed in the above-described manner, the flow proceeds to step S203. By the processing after step S203, the intake pressure at the closing of the intake valve 19 is based on the actual throttle opening degree TAr, the actual intake pressure PMr, the engine speed NE, and the like at this time. Is predicted, and the predicted intake pressure is calculated as the predicted intake pressure PMFWD. The processing of steps S203 to S206 is for calculating the basic intake pressure PMTA _bse used to calculate the predicted intake pressure PMFWD. The basic intake pressure PMTA _bse is calculated in consideration of the valve timing of the intake valve 19 changed by the valve timing variable mechanism 27 based on the actual throttle opening degree TAr and the like.
[113] The valve timing of the intake valve 19 is adjusted using the target travel angle θ calculated from the map of FIG. 11. In the case of homogeneous combustion, the target traveling angle θ is obtained based on the actual throttle opening degree TAr and the engine speed NE. The ECU 92 changes the valve timing variable mechanism 27 so that the actual traveling angle of the intake valve 19 obtained based on the detection signal from the cam position sensor 21b is close to the target traveling angle θ calculated from the map. The OCV 27a is controlled to drive. The valve timing adjusted in this way also affects the intake air amount.
[114] In step S203, the ECU 92 calculates the target travel angle θ by referring to the map of Fig. 11 based on the actual throttle opening degree TAr and the engine speed NE. In step S204, the ECU 92 performs intake at normal time when the valve timing of the intake valve 19 is set to the maximum traveling angle at the current actual throttle opening degree TAr and the engine speed NE. The pressure PM1 is calculated from the map of the maximum advancing angle of FIG. 12 based on the said throttle opening degree TAr and the engine speed NE. In the process of step S205, the ECU 92 is in a normal time when the valve timing of the intake valve 19 is set to the maximum delay angle at the current actual throttle opening degree TAr and the engine speed NE. Intake pressure PM2 is calculated from the map of the maximum delay angle in FIG. 13 based on the throttle opening degree TAr and the engine speed NE. The two maps are established by preliminary experiments and the like at standard atmospheric pressure.
[115] Next, in the process of step S206, the ECU 92 calculates the basic intake pressure PMTA _bse corresponding to the target traveling angle θ based on the following equation (4).
[116]
[117] In Equation 4, 60 represents the maximum traveling angle of the valve timing of the intake valve 19, and is determined by the valve timing variable mechanism 27. By calculating the basic intake pressure PMTA _bse based on Equation 4, the accurate basic intake pressure PMTA _bse corresponding to the target traveling angle θ is calculated. After calculating the basic intake pressure PMTA _bse , the flow proceeds to step S207. The process of step S207 is for correcting the basic intake pressure PMTA _bse to calculate the post-correction intake pressure PMTA.
[118] In the process of step S207, the ECU 92 calculates the atmospheric pressure correction coefficient K _pa 1 by referring to the map of FIG. 16 based on the atmospheric pressure PA, and the atmospheric pressure correction coefficient to the basic intake pressure PMTA _bse . The intake pressure PMTA after correction is calculated by multiplying (K _pa 1). As the atmospheric pressure PA becomes higher, the atmospheric pressure correction coefficient K _pa 1 becomes larger and approaches 1.0. Therefore, the higher the atmospheric pressure, the larger the post-correction intake pressure PMTA. After calculation of the intake pressure PMTA after correction, the process proceeds to step S208.
[119] Step S208 relates to the processing of steps S209 and S210. That is, in the process of step S209, the progressive change value PMSM is calculated by gradually changing the intake pressure PMSM after correction, and in the process of step S210, the progressive change value PMSM is stored in the intake pressure memory. It is stored as the value PMSM1. In the process of step S208, the ECU 92 sets the first intake pressure memory value PMSM1 memorized in the process of the previous step S210 as the previous gradual change value PMSM _i-1 .
[120] The reason why the gradual change value PMSM calculated in the gradual change process of step S209 is temporarily stored as the first intake pressure storage value PMSM1 in step S210 is explained in step S213 of FIG. 9 described below. This is because another process is executed using the gradual change value PMSM, and the gradual change value PMSM is changed by the process. Even in this case, the gradual change process in step S209 can be appropriately executed by setting the first intake pressure stored value PMSM1 to the previous gradual change value PMSM _i-1 in step S208. .
[121] After the processing in step S208 is executed, the ECU 92 calculates the current gradual change value PMSM _i in step S209 based on Equation 5 below. Specifically, after subtracting the change value PMSM _{i-1 which} is a progressive step from the intake pressure PMTA at the time of normal correction, and dividing by the predetermined value n, the division result is divided into the previous incremental change value ( PMSM _i-1 is added to calculate the current gradual change value PMSM _i .
[122]
[123] Fig. 14 shows the trend of the change value PMSM which is a gradual change with respect to the change in intake pressure PMTA after correction. In Fig. 14, the trend of the correction intake pressure PMTA is shown by the broken line, and the trend of the progressive change value PMSM is shown by the thick solid line. The dashed line indicates how the actual intake pressure PMr changes, while the post-correction intake pressure PMTA calculated from the map or the like changes as indicated by the broken line.
[124] As is apparent from Fig. 14, when the intake pressure PMTA after correction changes as indicated by the broken line according to the change of the accelerator pedal depression amount ACCP, for example, the progressive change value PMSM becomes the intake pressure after correction ( The change in PMTA) gradually changes as indicated by the thick solid line. How gradually the change value PMSM gradually changes with respect to the change in intake pressure PMTA after correction is determined by the predetermined value n of Equation 5. The predetermined value n is calculated based on the intake air pressure PMTA and the engine speed NE after correction by referring to a map (not shown) set in advance by experiment or the like.
[125] If the progressive change value PMSM is calculated in the process of step S209 and the first intake pressure stored value PMSM1 is stored in the process of step S210, the flow advances to step S211 of FIG. The processing of steps S211 to S213 is for predicting and calculating a gradual change value PMSM at the time of closing the intake valve 19 at this point in time.
[126] In the processing of step S211, the ECU 92 determines the number of times of the gradual change processing (number of gradual change processing) executed in step S209 from the present time until the intake valve 19 is closed (T / Δt ) Is calculated. That is, the number of times of the gradual change processing (T / Δt) obtains the time (T) from the present time until the intake valve 19 is closed, and the execution cycle (Δt) of the control value calculation routine (this embodiment In this example, it is calculated by dividing the time T by 8ms).
[127] Next, in the process of step S212, the ECU 92 sets the currently stored first intake pressure stored value PMSM1 or the last gradual change value PMSM as the previous gradual change value PMSM _i-1 . . Further, in the process of step S213, the ECU 92 executes a gradual change process according to the above equation (5) by the number of times of the gradual change process (T / Δt), thereby performing a T / Δt gradual change process. The gradual change value PMSM _i after execution or the gradual change value PMSM _i at the time of closing of the intake valve 19 are calculated. Thereafter, the ECU 92 stores the gradual change value PMSM _i as the second intake pressure storage value PMSM2 in the process of step S214.
[128] When the process of step S209 (FIG. 8) is executed at the time indicated by the dashed-dotted line L1 in FIG. 14, the current gradual change value PMSM _i calculated in the process is stored as the intake pressure storage value PMSM1. do. Next, when the process of step S213 is executed, a gradual change value PMSM _i at the time of closing of the intake valve 19 indicated by the dashed-dotted line L2 is calculated, and the gradual change value PMSM _i is almost one dashed line. At the time indicated by L1, it is stored as the second intake pressure stored value PMSM2.
[129] After the first and second intake pressure storage values PMSM1 and PMSM2 are stored, the intake pressure at the closing of the intake valve 19 is the difference ΔP1 between the storage values PMSM1 and PMSM2 (PMSM2-PMSM1). Can be predicted and calculated using That is, the intake pressure at the closing of the intake valve 19 is determined by the difference DELTA P1 between the first and second intake pressure stored values PMSM1 and PMSM2 at the present time (dotted dashed line L1). Is obtained by adding the actual intake pressure PMr detected by
[130] Since the output of the vacuum sensor 36 is affected by the pulsation of air flowing in the intake passage 32, the output of the vacuum sensor 36 is usually filtered by a CR filter or the like to remove the influence. Therefore, the actual intake pressure PMr is actually deviated from an appropriate value by a time constant such as a CR filter in the filtering process, so that the predicted intake pressure at the closing of the intake valve 19 becomes inaccurate.
[131] The process after step S215 in the predicted intake pressure calculation routine filters the first intake pressure stored value PMSM1 in consideration of the deviation of the actual intake pressure PMr, and uses the filter output PMSM1S _i to perform the process. This is for accurately predicting the intake pressure at the closing of the intake valve 19.
[132] In the process of step S215, the ECU 92 filters the first intake pressure stored value PMSM1 based on the following equation (6). In Equation 6, PMSM1S _i is a filter output of the first intake pressure storage value PMSM1, and the predetermined value m is a value set such that the time constant of the filtering process is equal to the time constant of the CR filter in the filtering process.
[133]
[134] The filter output PMSM1S _i obtained based on Equation 6 has a thin solid line in FIG. 14 when the gradual change value PMSM (first intake pressure storage box PMSM1) changes as indicated by the thick solid line in FIG. 14. Change as indicated by.
[135] Then, in the process of step S216, the ECU 92 subtracts the filter output PMSM1S _i from the second intake pressure storage value PMSM2 to calculate a difference ΔP2 therebetween. In addition, the ECU 92 adds a value obtained by adding the difference P2 to the actual intake pressure PMr in the process of step S217, or the intake pressure at the closing of the intake valve 19 or the predicted intake pressure PMFWD. ), The predicted intake pressure calculation routine is finished, and the control value calculation routine (Fig. 3) is returned.
[136] Therefore, when the storage processing of the first and second intake pressure storage values PMSM1 and PMSM2 is executed at the time indicated by the dashed-dotted line L1 in FIG. 14, the first intake pressure storage value PMSM1 at that time is stored. The filter output PMSM1S _i is used to calculate the predicted intake pressure PMFWD. That is, the predicted intake pressure PMFWD is the actual intake pressure PMr at the difference ΔP2 between the second intake pressure storage value PMSM2 and the filter output PMSM1S _i at the time indicated by the dashed-dotted line L1. It is calculated by adding.
[137] Since the difference DELTA P2 is calculated using the filter output PMSM1S _i instead of the first intake pressure stored value PMSM1, the predicted intake pressure PMFWD is obtained from the difference DELTA P2 or the like. The predicted intake pressure PMFWD can be calculated as the correct intake pressure at the closing of the intake valve 19 even if a deviation according to the time constant of the CR filter occurs in the intake pressure PMr.
[138] Next, the process of step S103 of the control value calculation routine will be described in detail with reference to FIG. FIG. 15 is a flowchart showing a virtual intake pressure calculation routine for calculating the virtual intake pressure PMv used as a value representing the engine load during stratified combustion. The virtual intake pressure calculation routine is illustrated in step S103 of FIG. It shows the details of the processing.
[139] In the process of step S301, the ECU 92 calculates the throttle opening degree at the time of execution of the homogeneous combustion by the acceleration pedal depressed amount ACCP during stratified combustion as the virtual throttle opening degree TAv. That is, as shown in FIG. 10, since the transition of the target throttle opening TAt at the time of homogeneous combustion with respect to the change of the acceleration pedal depressed amount ACCP is almost the same as the transition of the compensation value TAh, first TAh Assume = TAt. Under this assumption, the actual throttle opening degree TAr is calculated from the target throttle opening degree TAt in the reverse order of calculating the compensation value TAh based on Equation 2 or the like, and the throttle opening degree TAr is assumed to be virtual. It is treated as the throttle opening degree (TAv).
[140] If the target throttle opening (TAt) during homogeneous combustion is changed as indicated by the dashed-dotted line in the graph (d) of FIG. 7, the virtual throttle opening (TAv) calculated in this way is represented by a thin solid line for the change. It is changed with a predetermined response delay as shown. The change in the actual throttle opening (TAv) is the actual throttle during homogeneous combustion with a response delay as shown by the thin solid line in the graph (b) of FIG. 7 with respect to the change in the target throttle opening (TAt) during the homogeneous combustion. Corresponds to the change in the opening degree TA.
[141] After the virtual throttle opening degree Tav is calculated in the manner described above, the process proceeds to step S302. The processing of steps S302 to S305 corresponds to the processing of steps S203 to S206 of the predicted intake pressure calculation routine, and includes the basic intake pressure used to calculate the virtual intake pressure PMv ( PM _bse ). The basic intake pressure PM _bse is calculated in consideration of the valve timing of the intake valve 19 changed by the valve timing variable mechanism 27 based on the virtual throttle opening degree TAv and the like. This is because when the valve timing of the intake valve 19 is adjusted, the adjustment also affects the amount of intake air to the engine 11.
[142] In step S302, the ECU 92 sets the target traveling angle θ calculated with reference to the map of FIG. 11 based on the virtual throttle opening degree TAv and the engine speed NE, and the virtual traveling angle θv. Set to. The virtual advancing angle θv calculated using the virtual throttle opening degree TAv is a virtual value corresponding to the target advancing angle θ when homogeneous combustion is executed by the accelerator pedal depressed amount ACCP during stratified combustion. to be.
[143] In the process of the next step S303, the ECU 92 is normal when the valve timing of the intake valve 19 is set to the maximum traveling angle at the current virtual throttle opening degree TAv and the engine speed NE. The intake pressure PM1 at the time is calculated from the map of the maximum traveling angle shown in FIG. 12 based on the virtual throttle opening degree TAv and the engine speed NE. In the process of step S304, the ECU 92 performs intake at normal time when the valve timing of the intake valve 19 is set to the maximum delay angle at the current throttle opening degree TAv and the engine speed NE. Pressure PM2 is calculated from the map of the maximum delay angle shown in FIG. 13 based on the said virtual throttle opening degree TAv and engine rotation speed NE. The maps of Figs. 12 and 13 are the same as those used in steps S204 and S205 (Fig. 8) in the predicted intake pressure calculation routine.
[144] Next, in the process of step S305, the ECU 92 calculates the basic intake pressure PM _bse corresponding to the virtual traveling angle _θv based on Equation 7 below.
[145]
[146] In Equation 7, 60 represents the maximum traveling angle of the valve timing of the intake valve 19 as in Equation 6. By calculating the basic intake pressure PM _bse based on Equation 7, an accurate basic intake pressure PM _bse corresponding to the virtual traveling angle _θv is calculated. After the basic intake pressure PM _bse is calculated, the process proceeds to step S306. The process of step S306 corresponds to step S207 (FIG. 8) in the predicted intake pressure calculation routine, for calculating the post-correction intake pressure PMh by applying atmospheric pressure correction to the basic intake pressure PM _bse . will be.
[147] In the process of step S306, the ECU 92 calculates the post-correction intake pressure PMh by multiplying the basic intake pressure PM _bse by the atmospheric pressure correction coefficient K _pa 1. The atmospheric pressure correction coefficient K _pa 1 is the same as that used in step S207 in the predicted intake pressure calculation routine, and is calculated by referring to the map of FIG. 16 based on the atmospheric pressure PA. Therefore, as the atmospheric pressure PA increases, the intake pressure PMh after correction increases.
[148] In the process of the next step S307, the ECU 92 calculates the virtual intake pressure PMv based on Equation 8 below. Specifically, the current virtual intake pressure PMv divides the result of subtracting the previous virtual intake pressure PMv from the intake pressure PMh after correction by a predetermined value nsm, and divides the result of the division into a previous one. It calculates by adding to virtual intake pressure PMv. Furthermore, this calculation is repeatedly performed T / Δt times so that the virtual intake pressure PMv calculated as in the case of the predicted intake pressure PMFWD corresponds to the closing time of the intake valve 19.
[149]
[150] When the virtual throttle opening degree TAv changes as indicated by the thin solid line in the graph (d) of FIG. 7, for example, the virtual intake pressure PMv calculated in the above-described manner is shown by the thick solid line for the change. It changes with a predetermined response delay as shown. The response delay is determined by a predetermined value nsm of Equation 8. The predetermined value nsm is, for example, the actual throttle opening at the time of homogeneous combustion as the virtual intake pressure PMv is indicated by the bold solid line in the graph (b) of FIG. 7 in response to a predetermined accelerator pedal pressing operation. It is calculated by referring to a map based on the intake pressure PMh and the engine speed NE after correction in a manner that changes with respect to the trend (response delay) of the predicted intake pressure PMFWD with respect to the degree TAr. The map used for calculating the map is set in advance by experiment or the like.
[151] In the engine 11 in which the valve timing of the intake valve 19 is adjusted by the valve timing variable mechanism 27, the intake pressure is changed by the valve timing. However, the target advancing angle θ at the time of performing homogeneous combustion at the acceleration pedal depressed amount ACCP during stratified combustion is calculated as the virtual advancing angle θv, and is used to calculate the virtual intake pressure PMv. The intake pressure PM _bse is calculated in consideration of the virtual advancing angle _θv . Therefore, even in the engine 11 in which the valve timing of the intake valve 19 is adjusted, the virtual intake pressure PMv can be accurately calculated as a value corresponding to the predicted intake pressure PMFWD.
[152] When the virtual intake pressure PMv is calculated in the above-described manner, the virtual intake pressure calculation routine is temporarily terminated and returns to the control value calculation routine (FIG. 3), and the processing of steps S105 to S108 is executed. . As described above, through the processing of steps S105 to S108, the basic fuel injection amount Q _bse has the same parameter or intake pressure (predicted intake pressure PMFWD) in any combustion system of stratified combustion or homogeneous combustion. Or virtual intake pressure PMv}. Based on the basic fuel injection amount Q _bse , various control values such as a target ignition timing, a target EGR amount, and a final fuel injection amount Q _fin are calculated, and the engine 11 is controlled based on the control values. .
[153] This embodiment described above has the following advantages.
[154] In stratified combustion, the throttle opening when performing homogeneous combustion at the acceleration pedal depression amount (ACCP) at that time is calculated as the virtual throttle opening degree (TAv), and stratified combustion is performed at the acceleration pedal depression amount (ACCP). The intake air pressure at the time is calculated as the virtual intake pressure PMv based on the virtual throttle opening degree TAv. At the time of stratified combustion, various operation control of the engine 11 is performed by using the said virtual intake pressure PMv as a value which shows engine load.
[155] As a result, in any combustion system of stratified combustion and homogeneous combustion, a common parameter representing the intake amount to the engine or the intake pressure is used as a value representing the engine load, such as fuel injection amount control, ignition timing control, and EGR control. Various operation control of the engine 11 is performed. Therefore, various operation control of the engine 11 according to the engine load at the time of homogeneous combustion is related to the stratified combustion, and the matching of the engine output torque characteristics between the combustion schemes is made easy.
[156] During homogeneous combustion, a response delay occurs in response to a change in the actual throttle opening degree TAr with respect to a change in the predetermined accelerator pedal depression amount ACCP, and a predicted intake pressure PMFWD for the change in the actual throttle opening degree TAr. A response delay also occurs with the transition of. On the other hand, in stratified combustion, in response to the response delay of the actual throttle opening degree TAr, a response delay occurs in the transition of the virtual throttle opening degree TAv with respect to the change of the predetermined acceleration pedal depressed amount ACCP. . Furthermore, in response to the response delay of the predicted intake pressure PMFWD, a response delay also occurs in the trend of the virtual intake pressure PMv with respect to the change in the virtual throttle opening degree TAv. Accordingly, the virtual throttle opening degree TAv and the virtual intake pressure PMv are calculated in consideration of the response delay between the actual throttle opening degree TAr and the predicted intake pressure PMFWD, and the engine 11 is based on the virtual values. The accuracy of various operation control of the is improved.
[157] The change of the final fuel injection quantity Q _fin has a big influence on the engine output torque characteristic including the response characteristic in over-show of the output torque of the engine 11. The final fuel injection amount Q _fin is also calculated using the intake pressure as a value representing the engine load, regardless of the combustion system. Therefore, the engine output torque characteristic in the transient state of the engine 11 does not change between homogeneous combustion and stratified combustion. This makes it possible to match engine output torque characteristics between the combustion regimes. Since the final fuel injection amount Q _fin according to the engine load is calculated based on the intake pressure regardless of the combustion method, the experiment for optimizing the final fuel injection amount Q _fin calculated is simplified. That is, since the final fuel injection amount Q _fin only needs to be optimized for one parameter or intake pressure, there is no need to perform experiments for each parameter when the parameters used as the engine load are different for each combustion method. Experiment is simple
[158] In calculating the final fuel injection amount Q _fin , a mode correction factor K _mode is used to compensate for the difference in combustion efficiency between both combustion systems. Therefore, when the fuel injection amount control is executed based on the final fuel injection amount Q _fin at the time of stratified combustion, the accuracy of the engine output torque control can be improved based on the fuel injection amount control.
[159] The pumping loss of the engine 11 differs between stratified combustion and homogeneous combustion, the difference in pumping loss between the combustion schemes being changed by atmospheric pressure. However, when calculating the final fuel injection amount, the mode correction coefficient K _mode determined by the combustion method is used, and is corrected by the atmospheric pressure correction coefficient K _pa 2 which changes according to the atmospheric pressure PA. Thus, even if the difference in pumping loss varies with atmospheric pressure PA, engine output torque control is always executed correctly.
[160] The intake pressure of the engine 11 is also changed by the valve timing of the intake valve 19. However, at the time of stratified combustion, the target traveling angle θ of the valve timing when homogeneous combustion is executed from the acceleration pedal depressed amount ACCP at that time is calculated as the virtual traveling angle θv, and the virtual intake pressure PMv The basic intake pressure PM _bse for compensating for is obtained by considering the virtual traveling angle _θv . Therefore, even in the engine 11 in which the valve timing of the intake valve 19 is changed, the virtual intake pressure PMv can be calculated accurately at stratified combustion, and various operation control controls the virtual intake pressure PMv to load the engine. It can be executed by using as a value representing.
[161] (Second embodiment)
[162] A second embodiment of the present invention will be described with reference to FIGS. 17 to 24. This embodiment is related to the engine output torque in accordance with the difference generated between the virtual intake pressure PMv and the predicted intake pressure PMFWD at the time of switching of the combustion system due to product deviation, time dependent change, etc. of the throttle valve 23. It aims at preventing a step from occurring. This embodiment prevents the step of output torque by correcting the control values for the operation control of the engine 11 such as fuel injection amount, ignition timing and throttle opening degree, and in fuel injection amount control, ignition timing control and throttle opening degree control. Only is different from the first embodiment. Therefore, only the parts different from the first embodiment will be described, and the detailed description thereof will be omitted for the same parts as the first embodiment.
[163] In this embodiment, the switching procedure of the combustion system of the engine 11 will be described in more detail than in the first embodiment. When switching the combustion mode of the engine 11, fuel injection control, ignition timing control, throttle opening degree control, EGR control, and the like are switched between stratified combustion control and homogeneous combustion control. The switching of fuel injection control and ignition timing control according to the combustion method is executed based on the injection / ignition indication mode (FMODEI), and the switching of throttle opening degree control and EGR control according to the combustion method is based on the valve indication mode (FMODEB). Is executed. For example, the injection / ignition instruction mode FMODEI and the valve instruction mode FMODEB display stratified combustion as "0" and homogeneous combustion as "1".
[164] Therefore, when the injection / ignition indication mode FMODEI becomes 0, the fuel injection control and the ignition timing control are switched to stratified combustion control, and when the mode FMODEI becomes 1, the fuel injection control and the ignition timing control are homogeneous. Switch to control for combustion. When the valve instruction mode FMODEB is 0, the throttle opening degree control and the EGR control are switched to stratified combustion control. When the mode FMODEB is 1, the throttle opening degree control and the EGR control are homogeneous combustion control. Is switched to.
[165] When the combustion mode of the engine 11 is switched between stratified combustion and homogeneous combustion, the ECU 92 first instructs to switch between 0 and 1 of the valve instruction mode FMODEB. When the valve instruction mode FMODEB is switched between 0 and 1, the ECU 92 controls the throttle valve 23 and the EGR valve 43 to an opening degree that matches the switched combustion scheme. This control ensures that the throttle opening (TA) and EGR amounts are suitable for the switched combustion regime.
[166] After a predetermined time has elapsed since the switching instruction of the valve instruction mode FMODEB has occurred, the ECU 92 instructs switching between 0 and 1 of the injection / ignition instruction mode FMODEI. When the injection / ignition indication mode FMODEI is switched between 0 and 1, the ECU 92 controls the fuel injection valve 40 and the igniter 41a according to the switched combustion scheme. This control allows the fuel injection amount, fuel injection timing and ignition timing to be appropriate values for the switched combustion scheme.
[167] As described above, the switching instruction of the injection / ignition instruction mode FMODEI is provided after a predetermined time has elapsed from when the switching instruction of the valve instruction mode FMODEB has occurred. Therefore, at the time of switching of the combustion system, the switching instruction timing deviation occurs between the two modes FMODEB and FMODEI. The deviation of the switching instruction timing between the two modes FMODEB and FMODEI is based on the change in the operating state of the engine 11 based on the change in the opening degree of the throttle valve 23 and the EGR valve 43. It is provided because it responds slower than the change in the operating state of the engine 11 based on the change in the timing and the ignition timing.
[168] That is, when the valve instruction mode FMODEB changes, for example, the throttle opening degree changes, the change in the intake air amount with respect to the opening degree change has a response delay. On the other hand, when the injection / ignition instruction mode FMODEI changes, for example, the fuel injection amount changes, the fuel injection amount changes with favorable response to the change in the injection / ignition instruction mode FMODEI.
[169] By changing the switching instruction timings of both modes FMODEB and FMODEI in the above-described manner, the change in the operating state of the engine 11 based on the change of the injection / ignition instruction mode FMODEI is changed in the valve instruction mode FMODEB. Occurs at about the same timing as the change in the operating state of the engine 11 based on the above, thereby ensuring good switching of the combustion system.
[170] A final fuel injection amount Q _fin calculation procedure according to the present embodiment will be described with reference to FIG. 17. 17 is a flowchart showing a final fuel injection amount calculation routine. The final fuel injection amount calculation routine is executed in interruption every predetermined time, for example, via the ECU 92.
[171] The processing in step S401 corresponds to the processing in step S101 in FIG. 3. In the process of step S401, the ECU 92 calculates the target throttle opening degree TAt at the time of homogeneous combustion by referring to a known map based on the accelerator pedal depressed amount ACCP.
[172] In the process of step S402, the ECU 92 determines whether the valve instruction mode FMODEB is 0 (stratum combustion). If FMODEB = 0, the process proceeds to step 403. If FMODEB = 0, the process proceeds to step S404. The processing of steps S403 to S405 corresponds to the processing of steps S103 to S105 in FIG. 3.
[173] In the processing of step S404, the ECU 92 predicts intake at the time of closing the intake valve 19 based on the actual intake pressure PMr, the actual throttle opening TAr, the engine speed NE, and the like. The pressure (PMFWD) or the intake pressure is calculated. In the process of step S403, the ECU 92 generates a virtual intake pressure PMv having a value corresponding to the predicted intake pressure PMFWD when performing homogeneous combustion in the acceleration pedal depressed amount ACCP during stratified combustion. Calculate. The virtual intake pressure PMv is obtained based on the target throttle opening degree TAt and the like. The virtual throttle opening degree TAv is equal to the actual throttle opening when performing homogeneous combustion at the acceleration pedal depressed amount ACCP during homogeneous combustion.
[174] Next, in the process of step S405, the ECU 92 uses the virtual intake pressure PMv or the predicted intake pressure PMFWD as the intake pressure PM, and the basic fuel injection amount ( Q _bse ) Based on the basic fuel injection amount Q _bse , the final fuel injection amount Q _fin is calculated in the process of step S409 described below. The ECU 92 controls the driving of the fuel injection valve 40 to inject fuel having an amount corresponding to the final fuel injection amount Q _fin by a separate process.
[175] In the engine 11, the throttle valve 23 may have product deviations or time dependent changes, and foreign matter may be attached to the intake passage 32, in which case the predicted intake pressure PMFWD and the virtual intake pressure (PMv) may have a different value, for example, at the time of switching the combustion mode. This is because the virtual intake pressure PMv is calculated irrespective of the actual intake pressure PMr and the like, whereas the predicted intake pressure PMFWD is based on the actual intake pressure PMr that changes depending on the product deviation of the throttle valve 23 and the like. Because it is calculated.
[176] If the predicted intake pressure PMFWD and the virtual intake pressure PMv have different values before and after the switching of the combustion system, for example, a step occurs in the basic fuel injection amount Q _bse before and after the switching of the combustion system. If a step occurs in the output torque of the engine 11 due to the step of the basic fuel injection amount Q _bse , the runability is deteriorated by the step of the torque.
[177] According to this embodiment, the control values of the engine 11, such as fuel injection amount, ignition timing and throttle opening degree, are corrected so as to offset the step of engine torque at the time of switching the combustion system. This correction prevents a step from occurring in the engine torque at the time of switching of the combustion system or the like, and thus prevents a deterioration in running performance due to the step.
[178] When the homogeneous combustion is converted to stratified combustion, fuel injection amount correction is executed based on the predicted intake pressure PMFWD and the virtual intake pressure PMv, in order to prevent a step from occurring in the engine torque. On the other hand, when stratified combustion is converted to homogeneous combustion, the ignition timing delay is corrected to prevent the generation of a step in engine torque, depending on whether the predicted intake pressure PMFWD is greater than or less than the virtual intake pressure PMv. Each correction or correction of the throttle opening degree is selectively executed. That is, when the predicted intake pressure PMFWD is larger than the virtual intake pressure PMv, the ignition timing delay angle correction is executed based on the intake pressures PMFWD and PMv, and the predicted intake pressure PMFWD is the virtual intake pressure ( When smaller than PMv), the opening correction of the throttle opening degree is executed based on the intake pressures PMFWD and PMv.
[179] The final fuel injection amount calculation routine will be described again in detail. After the basic fuel injection amount Q _bse is calculated in the process of step S405, the flow advances to step S406. The processing of steps S406 and S407 occurs due to the difference between the predicted intake pressure PMFWD and the virtual intake pressure PMv when a difference occurs in the switching of the combustion mode from homogeneous combustion to stratified combustion. It is for preventing generation of a step of engine torque.
[180] In the process of step S406, the ECU 92 determines whether switching of the injection / ignition instruction mode FMODEI from 1 (homogeneous combustion) to 0 (stratum combustion) is instructed. If the answer to step S406 is no, the process proceeds to step S408. The process of step S408 corresponds to the process of step S107 of FIG. 3, and calculates a mode correction coefficient.
[181] On the other hand, if the answer is YES in the processing of step S406, the flow proceeds to step S407. From the following equation (9), the ECU 92 calculates the injection amount correction coefficient K1 used to prevent the generation of the step of the engine torque.
[182]
[183] In Equation 9, the predicted intake pressure PMFWD is the predicted intake pressure PMFWD just before the valve instruction mode FMODEB is changed from 1 (homogeneous combustion) to 0 (stratum combustion), and the virtual intake pressure PMv. Is the final value calculated in the process of step S403. As apparent from Equation 9, the injection amount correction coefficient K1 becomes smaller with respect to the reference value or 1.0 when the virtual intake pressure PMv becomes larger than the predicted intake pressure PMFWD, and the virtual intake pressure PMv becomes the predicted intake pressure ( Larger than 1.0 when smaller than PMFWD).
[184] In the process after step S408, the ECU 92 calculates the mode correction coefficient K _mode . Furthermore, in the process of step S409, the ECU 92 _{multiplies the} basic fuel injection amount Q _bse by the coolant temperature correction coefficient K _thw , the mode correction coefficient K _mode , and the injection amount correction coefficient K1. After the final fuel injection amount Q _fin is calculated, the final fuel injection amount calculation routine is temporarily terminated.
[185] The fuel injection control based on the final fuel injection amount Q _fin is corrected by the injection amount correction coefficient K1 calculated based on the predicted intake pressure PMFWD and the virtual intake pressure PMv. Therefore, when the homogeneous combustion is converted to stratified combustion, even if the predicted intake pressure PMFWD becomes different from the virtual intake pressure PMv, the generation of the engine torque step due to the difference is based on the injection amount correction coefficient K1. This is prevented by fuel injection amount correction.
[186] 18 and 19 show the transitions of the predicted intake pressure PMFWD, the virtual intake pressure PMv, the injection amount correction coefficient K1, and the engine torque when the homogeneous combustion is converted to stratified combustion.
[187] In the graph (a) of FIG. 18 and the graph (b) of FIG. 19, the solid line L1 shows the trend of the predicted intake pressure PMFWD, and the solid line L2 shows the trend of the virtual intake pressure PMv.
[188] For example, when switching of the injection / ignition indicating mode FMODEI from 1 (homogeneous combustion) to 0 (stratum combustion) is instructed, as shown in the graph (a) of FIG. 18, the virtual intake pressure PMv May be greater than the predicted intake pressure PMFWD. In this case, the value of the intake pressure used to calculate the basic fuel injection amount Q _bse changes as indicated by broken lines in the graph (a) of FIG. 18. Therefore, when the switching of the injection / ignition indicating mode FMODEI from 1 to 0 is instructed, the value of the intake air pressure increases rapidly. As the value of the intake pressure increases, the basic fuel injection amount Q _bse increases rapidly.
[189] When switching of the injection / ignition instruction mode FMODEI from 1 to 0 is instructed, as shown in the graph (b) of FIG. 18, the injection amount correction coefficient K1 changes to a small value. The fuel injection amount correction based on the injection amount correction coefficient K1 can prevent the step of the engine torque from the increase side from occurring when the switching of the injection / ignition instruction mode FMODEI from 1 to 0 is instructed. As a result, the engine torque changes gently as shown in graph (c) of FIG. 18 when the homogeneous combustion is converted to stratified combustion.
[190] When the switching of the injection / ignition indication mode FMODEI from 1 to 0 is instructed, as shown in the graph (a) of FIG. 19, the virtual intake pressure PMv becomes smaller than the predicted intake pressure PMFWD. . In this case, the value of the intake pressure used to calculate the basic fuel injection amount Q _bse changes as indicated by broken lines in the graph (a) of FIG. 19. Therefore, when the switching of the injection / ignition instruction mode FMODEI from 1 to 0 is instructed, the value of the intake air pressure decreases rapidly. As the value of the intake pressure decreases, the basic fuel injection amount Q _bse decreases rapidly.
[191] When switching of the injection / ignition instruction mode FMODEI from 1 to 0 is instructed, as shown in the graph (b) of FIG. 19, the injection amount correction coefficient K1 changes to a large value. The fuel injection amount correction based on the injection amount correction coefficient K1 can prevent generation of a step of the engine torque to the reduction side when the switching of the injection / ignition instruction mode FMODEI from 1 to 0 is instructed. As a result, the engine torque changes slowly as shown in graph (c) of FIG. 19 when switching from homogeneous combustion to stratified combustion.
[192] If an attempt is made to adjust the engine torque by correction of the ignition timing during stratified combustion, the ignition can be executed when there is no air-fuel mixture having a high fuel concentration around the spark plug by the change of the ignition timing. This makes the combustion state unstable and can cause ignition misfire. In this regard, the fuel injection amount is corrected to prevent the generation of a step in engine torque when switching from homogeneous combustion to stratified combustion.
[193] 20 to 24, ignition timing control and throttle opening degree control for preventing a step from occurring in engine torque when switching from stratified combustion to homogeneous combustion will be described. At the time of switching the combustion system, if the predicted intake pressure PMFWD is larger than the virtual intake pressure PMv, generation of a step of engine torque is prevented by ignition timing control. If the predicted intake pressure PMFWD is smaller than the virtual intake pressure PMv, generation of a step of engine torque is prevented by throttle opening degree control.
[194] 20 is a flowchart showing a routine for calculating a target ignition timing used for ignition timing control. The routine is executed in the interruption every predetermined time via the ECU 92.
[195] In the process of step S501, the ECU 92 calculates a basic ignition timing SA _bse . The basic ignition timing SA _bse is calculated based on the predicted intake pressure PMFWD and the engine speed NE at homogeneous combustion, and the basic fuel injection amount Q _bse and the engine speed NE at stratified combustion. Calculated based on The basic ignition timing SA _bse is used to calculate the target ignition timing SAt in the processing of step S505 described below. When the target ignition timing SAt is calculated, the ECU 92 controls the actual ignition timing to be the target ignition timing SAt by separate processing.
[196] After the process of step S501 is executed, the flow advances to step S502. The processing of steps S502 to S505 is performed by the conversion in the direction in which the predicted intake pressure PMFWD becomes larger than the virtual intake pressure PMv when a conversion occurs in the transition from stratified combustion to homogeneous combustion. This is to prevent the occurrence of a step of the engine torque toward the increase side generated.
[197] In the process of step S502, the ECU 92 determines whether switching of the injection / ignition instruction mode FMODEI from 0 (stratum combustion) to 1 (homogeneous combustion) is instructed. If the answer is yes, the process proceeds to step S503. In the process of step S503, the ECU 92 determines whether the value PMFWD-PMv obtained by subtracting the virtual intake pressure PMv from the predicted intake pressure PMFWD is a positive value. If PMFWD-PMv is a positive value, that is, the predicted intake pressure PMFWD is converted in a direction that becomes larger than the virtual intake pressure PMv, step S504 is reached.
[198] In the process of step S504, the ECU 92 calculates the ignition timing correction amount K2 based on PMFWD-PMv. The larger the PMFWD-PMv, the larger the ignition timing correction amount K2. In the process of the next step S505, the ECU 92 calculates the target ignition timing SAt by adding the ignition timing correction amount K2 to the basic ignition timing SA _bse , and then temporarily executes the target ignition timing calculation routine. Quit.
[199] In the ignition timing control based on the target ignition timing SAt, correction to the delay angle side is applied by the ignition timing correction amount K2. Therefore, when the predicted intake pressure PMFWD is converted in the direction of becoming larger than the virtual intake pressure PMv when it is switched to homogeneous combustion in stratified combustion, generation of a step of engine torque to the increase side by the conversion causes an ignition timing delay. Prevented by each correction.
[200] If it is determined in the processing of step S503 that PMFWD-PMv is not a positive value, the ignition timing correction amount K2 is set to 0 in the processing of step S507, and the flow advances to the next step S505. Therefore, if the predicted intake pressure PMFWD is equal to or less than the virtual intake pressure PMv, the ignition timing delay angle correction is not performed.
[201] If the answer to the processing of step S502 is no, the process proceeds to step S506. The processing of step S506 and step S508 gradually brings the ignition timing correction amount K2 close to zero.
[202] In the process of step S506, the ECU 92 determines whether the ignition timing correction amount K2 is greater than zero. If K2> 0, the value obtained by subtracting the predetermined value a2 from the ignition timing correction amount K2 is set as a new ignition timing correction amount K2 in the process of step S508, and then the flow advances to step S505. If K2> 0, the ignition timing correction amount K2 is set to 0 in the processing of step S507 and then proceeds to step S505.
[203] In order to prevent occurrence of a step of engine torque when switching from stratified combustion to homogeneous combustion, the ignition timing correction amount K2 is set to a value greater than zero in the processing of step S504, and then the ignition timing correction amount K2 is gradually increased. To zero.
[204] The time chart of FIG. 21 shows changes in the predicted intake pressure PMFWD, the virtual intake pressure PMv, the ignition timing correction amount K2, and the engine torque when switching from stratified combustion to homogeneous combustion.
[205] In the graph (a) of FIG. 21, the solid line L1 represents the trend of the predicted intake pressure PMFWD, and the solid line L2 represents the trend of the virtual intake pressure PMv.
[206] For example, when switching of the injection / ignition indicating mode FMODEI from 0 (stratum combustion) to 1 (homogeneous combustion) is instructed, as shown in the graph (a) of FIG. 21, the predicted intake pressure PMFWD is It may be greater than the virtual intake pressure PMv. In this case, the value of the intake pressure used to calculate the basic fuel injection amount Q _bse changes as indicated by broken lines in the graph (a) of FIG. 21. Therefore, when the switching of the injection / ignition instruction mode FMODEI from 0 to 1 is instructed, the value of the intake air pressure increases rapidly. As the value of the intake pressure increases, the basic fuel injection amount Q _bse increases rapidly.
[207] When switching of the injection / ignition instruction mode FMODEI from 0 to 1 is instructed, as shown in the graph (b) of FIG. 21, the ignition timing correction amount K2 changes to a large value. The ignition timing delay angle correction based on the ignition timing correction amount K2 can prevent generation of a step of the engine torque toward the increase side. As a result, the engine torque slowly changes as shown in the graph (c) of FIG. 21 when switching from stratified combustion to homogeneous combustion.
[208] After the switching to the injection / ignition indicating mode FMODEI is instructed to 1, the ignition timing correction amount K2 gradually decreases to 0 as shown in the graph (b) of FIG.
[209] The throttle opening degree control for preventing the generation of a step in engine torque when switching from stratified combustion to homogeneous combustion will be described.
[210] 23 is a flowchart showing a routine for calculating the target throttle opening degree. The routine is executed in the interruption every predetermined time via the ECU 92.
[211] In the process of step S601, the ECU 92 calculates a basic throttle opening degree TA _bse . The basic throttle opening TA _bse is calculated based on the accelerator pedal _depressed amount ACCP during homogeneous combustion, and calculated based on the basic fuel injection amount Q _bse during stratified combustion. The basic throttle opening degree TA _bse is used to calculate the target throttle opening degree TAt in the process of step S605 described below. When the target throttle opening degree TAt is calculated, the ECU 92 controls the actual throttle opening degree TAr to become the target throttle opening degree TAt by a separate process.
[212] After the process of step S601 is executed, the flow proceeds to step S602. The processing of steps S602 to S605 occurs by the conversion in the direction in which the predicted intake pressure PMFWD becomes smaller than the virtual intake pressure PMv when the conversion occurs in the transition from stratified combustion to homogeneous combustion. This is to prevent the occurrence of the step of the engine torque to the reduction side.
[213] In the process of step S602, the ECU 92 determines whether switching of the injection / ignition instruction mode FMODEI from 0 (stratum combustion) to 1 (homogeneous combustion) has been instructed. If the answer is yes, the process proceeds to step S603. In the process of step S603, the ECU 92 determines whether or not the value PMFWD-PMv obtained by subtracting the virtual intake pressure PMv from the predicted intake pressure PMFWD is a negative value. If PMFWD-PMv is a negative value, that is, when the predicted intake pressure PMFWD is converted to a direction smaller than the virtual intake pressure PMv, the flow proceeds to step S604.
[214] In the process of step S604, the ECU 92 calculates a throttle opening degree correction amount K3 based on PMFWD-PMv. The smaller the PMFWD-PMv, the larger the throttle opening correction amount K3. In the processing of the next step S605, the ECU 92 calculates the target throttle opening degree TAt by adding the throttle opening degree correction amount K3 to the basic throttle opening degree TA _bse , and then calculating the target throttle opening degree. Temporarily terminate the routine.
[215] The throttle opening degree control based on the target throttle opening degree TAt uses the throttle opening degree correction amount K3 calculated based on the predicted intake pressure PMFWD and the virtual intake pressure PMv in the throttle opening direction. Perform the calibration. The correction increases the intake air amount to the engine 11 and increases the fuel injection amount. As a result, the amount of air-fuel mixture charged in the combustion chamber 16 becomes large, and thus the engine torque is increased. Therefore, when switching from stratified combustion to homogeneous combustion, even if the predicted intake pressure PMFWD is converted in a direction smaller than the virtual intake pressure PMv, the generation of the step of the engine torque to the reduction side by the conversion is prevented. .
[216] If it is determined in the processing of step S603 that PMFWD-PMv is not a negative value, the throttle opening degree correction amount K3 is set to 0 in the processing of step S607 and then proceeds to step S605. Therefore, when the predicted intake pressure PMFWD is equal to or larger than the virtual intake pressure PMv, the opening correction of the throttle opening degree is not performed.
[217] If the answer to the processing of step S602 is no, the process proceeds to step S606. The processing of step S606 and step S608 gradually brings the throttle opening correction amount K3 close to zero.
[218] In the process of step S606, the ECU 92 determines whether the throttle opening degree correction amount K3 is greater than zero. If K3> 0, the value obtained by subtracting the predetermined value a3 from the throttle opening correction amount K3 is set as a new throttle opening correction amount K3 in the process of step S608, and the flow advances to the next step S605. do. If K> 0, the throttle opening correction amount K3 is set to 0 in the process of step S607, and the flow advances to the next step S605.
[219] The throttle opening degree correction amount K3 is set to a value larger than 0 in the processing of step S604, in order to prevent a step in the engine torque when it is rolled over from the stratified combustion to homogeneous combustion. ) Gradually approaches zero.
[220] The time chart of FIG. 22 shows changes in the predicted intake pressure PMFWD, the virtual intake pressure PMv, the throttle opening correction amount K3, and the engine torque when switching from stratified combustion to homogeneous combustion.
[221] In the graph (a) of FIG. 22, the solid line L1 represents the trend of the predicted intake pressure PMFWD, and the solid line L2 represents the trend of the virtual intake pressure PMv.
[222] For example, when switching of the injection / ignition indicating mode FMODEI from 0 (stratum combustion) to 1 (homogeneous combustion) is instructed, as shown in graph (a) of FIG. 22, the predicted intake pressure PMFWD is It may be smaller than the virtual intake pressure PMv. In this case, the value of the intake pressure used to calculate the basic fuel injection amount Q _bse changes as indicated by broken lines in the graph (a) of FIG. 22. Therefore, when the switching of the injection / ignition instruction mode FMODEI from 0 to 1 is instructed, the value of the intake air pressure decreases rapidly. As the value of the intake pressure decreases, the basic fuel injection amount Q _bse decreases rapidly.
[223] When switching of the injection / ignition indicating mode FMODEI from 0 to 1 is instructed, as shown in the graph (b) of FIG. 22, the throttle opening degree correction amount K3 changes to a large value. The throttle opening correction based on the throttle opening correction amount K3 increases the amount of air-fuel mixture charged in the combustion chamber 16 of the engine 11, thus increasing the engine torque. Therefore, when switching of the injection / ignition instruction mode FMODEI from 0 to 1 is instructed, it is possible to prevent a step from occurring in the engine torque to the reduction side. As a result, even when switching from stratified combustion to homogeneous combustion, the engine torque changes gently as shown in graph (c) of FIG.
[224] After the switching of the injection / ignition indicating mode FMODEI from 0 to 1 is instructed, the throttle opening degree correction amount K3 gradually decreases to 0 as shown in the graph (b) of FIG.
[225] The increase in the intake air amount based on the correction of the opening of the throttle opening degree is delayed due to the intake resistance with respect to the switching instruction timing of the injection / ignition instruction FMODEI. The delayed increase in the intake amount makes it possible to suitably prevent the occurrence of the step of the engine torque to the reduction side.
[226] Therefore, according to the present embodiment, when the throttle opening degree correction is executed, the timing of the switching instruction of the injection / ignition instruction mode FMODEI from 0 to 1 is practical to the switching instruction timing of the injection / ignition instruction mode FMODEI. Delay. As a result, the timing when the combustion system is switched from stratified combustion to homogeneous combustion is delayed. Although the increase in the intake amount is delayed with respect to the correction of the opening of the throttle opening degree, the timing of the increase in the intake amount coincides with the timing when stratified combustion is converted to homogeneous combustion. This makes it possible to suitably prevent the occurrence of the step of the engine torque on the reduction side.
[227] The delay process of switching from stratified combustion to homogeneous combustion will be described with reference to FIG. FIG. 24 is a flowchart showing a routine for delaying the switching of the combustion system upon opening correction of the throttle opening degree. The switching delay routine is executed at an interruption every predetermined time, for example, via the ECU 92.
[228] In the process of step S701, the ECU 92 determines whether the throttle opening correction amount K3 has changed from 0 to a value greater than zero. If the answer is no, go to step S704; if the answer is yes, go to step S702. When the switching of the injection / ignition instruction mode FMODEI from 0 (stratified combustion) to 1 (homogeneous combustion) is instructed in the processing of step S602 of FIG. 23 and correction of opening of the throttle opening degree is executed, step S701. Judge as 'yes'.
[229] In the process of step S702, the ECU 92 stores 1 in the predetermined area of the RAM 95 as the delay execution flag F. As shown in FIG. The delay execution flag F is used to determine whether the actual switching of the injection / ignition indication mode FMODEI should be delayed with respect to the switching instruction timing of the injection / ignition indication mode FMODEI, that is, the combustion method from stratified combustion to homogeneous combustion. This is to determine whether the transition should be delayed. The delay execution flag F is used to execute the processing of step S706 described below.
[230] In the process of the next step S703, the ECU 92 sets the switching delay counter C based on the value PMFWD-PMv obtained by subtracting the virtual intake pressure PMv from the predicted intake pressure PMFWD. The changeover delay counter C determines a delay time for switching the combustion type, and increases as the PMFWD-PMv decreases. The larger the switching delay counter C is, the longer the delay time of the combustion system is.
[231] In the process of step S704, the ECU 92 determines whether the switching delay counter C is greater than zero. Immediately after the throttle opening correction amount K3 becomes greater than zero, i.e., when proceeding from step S703 to step S704, the switching delay counter C becomes larger than zero, so as a 'yes' in the processing of step S704. It determines, and it progresses to step S705. In the process of step S705, the ECU 92 sets the value obtained by subtracting 1 from the switching delay counter C as a new switching delay counter C, and then temporarily ends the switching delay routine.
[232] When the switching delay counter C gradually approaches 0 by the process of step S705, if C = 0, it is determined as 'no' in the process of step S704, and the process proceeds to step S706. . In the process of step S706, the ECU 92 determines whether or not 1 is stored in the predetermined area of the RAM 95 as the delay execution flag F. As shown in FIG. If F = 1, the injection / ignition indication mode FMODEI is switched to 1 (homogeneous combustion) in the processing of step S707.
[233] In this way, the switching of the combustion system from stratified combustion to homogeneous combustion is delayed by delaying the actual switching of the injection / ignition indicating mode FMODEI by the switching delay counter C. FIG. Next, the ECU 92 stores 0 in the predetermined area of the RAM 95 as the delay execution flag F in the processing of step S708, and then temporarily terminates the switching delay routine.
[234] The switching delay flag F is normally 0, and remains 1 until after the throttle opening correction amount K3 becomes larger than zero, until the injection / ignition indicating mode FMODEI is switched to one. In the normal state of the engine 11 in which no switching of the combustion system or the like occurs, if F = 0, it is determined as "no" in the process of step S706, and the switching delay routine is temporarily terminated.
[235] This embodiment described above has the following advantages in addition to the advantages of the embodiment of FIGS.
[236] When product deviations or time dependent changes occur in the throttle valve 23, the predicted intake pressure PMFWD and the virtual intake pressure PMv may be different from each other, for example, in the switching of the combustion mode, the difference being the combustion When the system is switched, a step is generated in the engine torque. The generation of the engine torque step can be suitably prevented by correcting the fuel injection amount, the ignition timing or the throttle opening degree. This improves runability.
[237] When the throttle opening degree is corrected to the open side in order to prevent the occurrence of a step of the engine torque, the switching timing of the combustion system is delayed. Therefore, even if the change of the actual intake air amount with respect to the correction of the opening of the throttle opening degree is delayed, it is possible to suitably prevent the occurrence of the step of the engine torque.
[238] (Third embodiment)
[239] A third embodiment of the present invention will be described with reference to Figs. 25-29. As in the embodiment of FIGS. 17 to 24, the present embodiment prevents generation of a step in the output torque of the engine 11 due to a difference between the virtual intake pressure PMv and the predicted intake pressure PMFWD. The purpose.
[240] In this embodiment, the virtual intake pressure PMv is calculated not only during homogeneous combustion but also in stratified combustion, and the fuel injection amount is corrected based on the predicted intake pressure PMFWD and the virtual intake pressure PMv in stratified combustion. Different from the embodiment of FIGS. 17 to 24. In addition, in this embodiment, since the prevention of the step of the output torque is performed only by the correction of the fuel injection amount, the throttle opening degree control and the ignition timing control are the same as in the embodiment of Figs. Therefore, only parts different from the embodiments of FIGS. 1 to 24 will be described, and descriptions of the same parts as the embodiments of FIGS. 1 to 24 will be omitted.
[241] First, an outline of fuel injection control according to the present embodiment will be described with reference to FIGS. 25 and 26.
[242] In the graph (a) of FIG. 25 and the graph (a) of FIG. 26, the solid line L3 represents the trend of the predicted intake pressure PMFWD with respect to the change of the engine load, and the solid line L4 represents the change of the engine load. The trend of the virtual intake pressure PMv is shown. The predicted intake pressure PMFWD is calculated based on the actual intake pressure PMr and the like, and the virtual intake pressure PMv is calculated regardless of the actual intake pressure PMr and the like.
[243] As described above, when the throttle valve 23 has a product deviation or time dependent change and foreign matter is attached to the intake valve 32, the values of the predicted intake pressure PMFWD and the virtual intake pressure PMv are different from each other. . If the values of the predicted intake pressure PMFWD and the virtual intake pressure PMv used to calculate the basic fuel injection amount Q _bse differ from each other before and after the switching of the combustion system, for example, the basic fuel before and after the switching of the combustion system A step occurs in the injection amount Q _bse . The step of the basic fuel injection amount Q _bse generates a step in the output torque of the engine 11, as indicated by the solid line in the graph (b) of FIG. 25 and the graph (b) of FIG. 26.
[244] Therefore, according to this embodiment, the virtual intake pressure PMv is calculated not only during stratified combustion but also during homogeneous combustion. Next, the fuel injection amount is corrected at the time of stratified combustion based on the predicted intake pressure PMFWD and the virtual intake pressure PMv at the time of homogeneous combustion. The correction eliminates the step of the engine torque and improves runability.
[245] The graph (a) of FIG. 25 shows an example in which the virtual intake pressure PMv becomes smaller than the predicted intake pressure PMFWD at the time of homogeneous combustion. In this case, as shown by the solid line in the graph (b) of FIG. 25, at the time of switching the combustion system, the engine torque at the time of stratified combustion becomes smaller than the engine torque at the homogeneous combustion.
[246] Therefore, according to the present embodiment, the final fuel injection amount Q _fin at stratified combustion is corrected to the increasing side based on the predicted intake pressure PMFWD and the virtual intake pressure PMv. Correction of the fuel injection amount increases the engine torque during stratified combustion, and thus prevents generation of engine torque step upon switching of the combustion mode, so that the engine torque is smooth as indicated by broken lines in Fig. 25B. Is changed.
[247] The graph (a) of FIG. 26 shows an example in which the virtual intake pressure PMv becomes larger than the predicted intake pressure PMFWD at the time of homogeneous combustion. In this case, as shown by the solid line in the graph (b) of FIG. 26, the engine torque at the time of stratified combustion at the time of switching of the combustion system becomes larger than the engine torque at the homogeneous combustion.
[248] Therefore, according to the present embodiment, the final fuel injection amount Q _{fin in} stratified combustion is corrected to the reduction side based on the predicted intake pressure PMFWD and the virtual intake pressure PMv. Correction of the fuel injection amount increases engine torque during stratified combustion, and thus prevents generation of engine torque step upon switching between combustion modes, so that the engine torque is gentle as indicated by broken lines in Fig. 26B. To change.
[249] Next, the control procedure of the fuel injection amount is demonstrated with reference to FIG. 27 is a flowchart showing a final fuel injection amount calculation routine according to the present embodiment. The routine is executed at interruptions every predetermined time, for example via the ECU 92.
[250] The processing of steps S801, S802, S803, and S804 corresponds to the processing of steps S401, S402, S403, and S404.
[251] The ECU 92 calculates the target throttle opening degree TAt at the time of homogeneous combustion based on the accelerator pedal depressed amount ACCP in the process of step S801, and the virtual intake pressure PMv in the process of step S802. To calculate. Next, the ECU 92 determines whether the valve instruction mode FMODEB is 0 (stratum combustion) in the process of step S803. According to this embodiment, the virtual intake pressure PMv is calculated in the process of step S802 regardless of whether FMODEB = 0. Therefore, the virtual intake pressure PMv is calculated not only during homogeneous combustion but also during stratified combustion.
[252] If it is determined in the processing of step S803 that FMODEB = 0, the flow advances to step S805, and if it is determined that FMODEB = not 0, the estimated intake pressure PMFWD is calculated in the processing of step S804, and then the step ( S805). Therefore, the predicted intake pressure PMFWD is calculated only when FMODEB is 1 (homogeneous combustion).
[253] In the process of step S805, the ECU 92 determines whether the injection / ignition instruction mode FMODEI is 0 (stratum combustion). If FMODEI = 0, the basic fuel injection amount Q _bse is calculated based on the virtual intake pressure PMv and the like in the process of step S806. The ECU 92 sets the learning value described below in the processing of the next step S807 as the injection amount correction coefficient K4, and then proceeds to step S811.
[254] The processing of step S811 and step S812 corresponds to the processing of step S408 and step S409. The ECU 92 calculates the mode correction coefficient K _mode in the process of step S811. Next, the final fuel injection amount Q _fin is, in the process of step S812, the coolant temperature correction coefficient K _thw , the mode correction coefficient K _mode and the injection amount correction coefficient K4, to the basic fuel injection amount Q _bse . Is calculated by multiplying thereafter, and the final fuel injection amount calculation routine is temporarily finished.
[255] After the final fuel injection amount Q _fin is calculated, the ECU 92 controls the driving of the fuel injection valve 40 in a separate process, and injects an amount of fuel corresponding to the final fuel injection amount Q _fin . The fuel injection amount is corrected by the injection amount correction factor K4 (learning value QG1), and the correction adjusts the engine torque.
[256] The learning value QG1 is a value which increases or decreases according to the pressure difference DPMK between the predicted intake pressure PMFWD and the virtual intake pressure PMv during homogeneous combustion. That is, the learning value QG1 is set to a smaller value when the virtual intake pressure PMv is much larger than the predicted intake pressure PMFWD. In this case, the injection amount correction coefficient K4 (learning value QG1) reduces the final fuel injection amount Q _fin at the time of stratified combustion, whereby the engine torque is reduced. As a result, the engine torque changes smoothly even when the combustion system is switched.
[257] The learning value QG1 is set to a large value when the virtual intake pressure PMv is much smaller than the predicted intake pressure PMFWD. In this case, the injection amount correction coefficient K4 (learning value QG1) increases the final fuel injection amount Q _fin at the time of stratified combustion, thereby increasing the engine torque. Therefore, engine torque changes smoothly even at the time of switching of a combustion system.
[258] On the other hand, if it is determined in the processing of step S805 that the injection / ignition instruction mode FMODEI is 1 (homogeneous combustion), the process proceeds to step S808. The ECU 92 calculates the basic fuel injection amount Q _bse based on the predicted intake pressure PMFWD and the like in the processing of step S808, and _{sets the} injection quantity correction coefficient K4 to 1.0 in the processing of step S809. After that, the process after step S811 is executed. At the time of homogeneous combustion, since the injection amount correction coefficient K4 is set to 1.0 in the process of step S809, correction of the fuel injection amount based on the above coefficient K4 (learning value QG1) is not performed.
[259] The calculation procedure of the learning value QG1 is demonstrated with reference to FIG. 28 is a flowchart showing a routine for calculating the learning value QG1. The routine is executed in the interruption every predetermined time via the ECU 92.
[260] The processing of steps S901 to S905 is for determining whether the driving state of the engine 11 is suitable for the calculation of the learning value QG1. The ECU 92 judges whether or not the engine speed NE has a value between the predetermined value a and the predetermined value b in the processing of step S901, and the actual intake air in the processing of step S902. It is determined whether the pressure PMr has a value between the predetermined value α and the predetermined value β. The operating state of the engine 11 in which the answers in the processing of steps S901 and S902 are both YES means that the operating region of the engine 11 when the homogeneous combustion is executed, that is, the engine 11 is relatively When operating at low speeds and low loads.
[261] Next, in the process of step S903, the ECU 92 determines whether the cooling water temperature is equal to or greater than the predetermined value c, that is, whether or not the warming up of the engine 11 is completed. Furthermore, in the process of step S904, the ECU 92 determines whether the absolute value of the change DPMr of the actual intake pressure PMr per unit time is smaller than the predetermined value d, that is, the actual intake pressure PMr. Determine if the change is small enough. In the processing of the next step S905, the ECU 92 determines whether the homogeneous combustion counter C _mode indicating the execution period of the homogeneous combustion is larger than the predetermined value e, i.e., a predetermined time has elapsed from the start of stratified combustion. Determine whether or not.
[262] A counter processing routine for counting up and resetting of the homogeneous combustion counter C _mode will be described with reference to the flowchart of FIG. 29. The counter processing routine is executed in the interruption every predetermined time via the ECU 92.
[263] In the process of step S1001, the ECU 92 determines whether the valve instruction mode FMODEB and the injection / ignition instruction mode FMODEI are 0 (stratum combustion). If both modes FMODEB and FMODEI are both 0 (stratum combustion), the homogeneous combustion counter C _mode is set to 0 in the processing of step S1002. If both modes FMODEB and FMODEI are both 1 (homogeneous combustion), the homogeneous combustion counter C _mode is added by 1 in the process of step S1003. After executing one of the processes of step S1002 and step S1003, the ECU 92 temporarily terminates the counter processing routine. Homogeneous combustion counter (C _mode ) is counted up while homogeneous combustion is performed. Therefore, the time elapsed from the execution of the homogeneous combustion based on the homogeneous combustion counter C _mode can be known accurately.
[264] In the operating state of the engine 11 in which the answers in the processing of steps S903 to S905 in Fig. 28 are all YES, the homogeneous combustion is executed for a predetermined time while the warm-up of the engine 11 is completed. When the change in the actual intake pressure PMr is small. If the answer in any of the processes of steps S901 to S905 is NO, the learning value calculation routine is temporarily terminated, whereas if all the answers are YES, the flow proceeds to step S906. .
[265] In the process of step S906, the ECU 92 calculates the pressure difference DPMK by subtracting the value obtained by multiplying the virtual intake pressure PMv by the learning value QG1 from the predicted intake pressure PMFWD. Next, the process proceeds to step S907. The process after step S907 is for calculating the learning value QG1 used in the process of step S807 in FIG. 27 according to the pressure difference DPMK.
[266] In the process of step S907, the ECU 92 determines whether the pressure difference DPMK is smaller than the predetermined value (-f) (f> 0). If it is determined that the value obtained by multiplying DPMK < -f or the virtual intake pressure PMv by the learning value QG1 is greater than the predicted intake pressure PMFWD, in the processing of step S908, the current learning value QG1 The value obtained by subtracting the predetermined value g from is set as a new learning value QG1, after which the learning value calculating routine is temporarily terminated.
[267] If the virtual intake pressure PMv is much larger than the predicted intake pressure PMFWD, the learning value QG1 becomes gradually smaller in the processing of step S908 in the manner described above. Further, the injection amount correction coefficient K4 set in accordance with the learning value QG1 also gradually decreases in the processing of step S807 in FIG. 27. As a result, the final fuel injection amount Q _fin at the time of stratified combustion is corrected to the reduction side based on the injection amount correction coefficient K4. Therefore, even when the virtual intake pressure PMv becomes much larger than the predicted intake pressure PMFWD, the engine torque changes gently in the switching of the combustion system or the like.
[268] In the process of step S907, if DPMK <-f, the process proceeds to step S909. In the process of step S909, the ECU 92 determines whether the pressure difference DPMK is larger than the predetermined value f. Determine whether or not. If it is determined that the value obtained by multiplying DPMK > f or the virtual intake pressure PMv by the learning value QG1 is smaller than the predicted intake pressure PMFWD, in the process of step S910, the current learning value QG1 A value obtained by adding the predetermined value g is set as a new learning value QG1, after which the learning value calculating routine is temporarily terminated. If DPMK> f in the processing of step S909, the learning value calculation routine is also temporarily terminated.
[269] If the virtual intake pressure PMv is much smaller than the predicted intake pressure PMFWD, the learning value QG1 gradually increases in the processing of step S910 in the manner described above. Moreover, the injection amount correction coefficient K4 set in accordance with the learning value QG1 also gradually increases in the processing of step S807 in FIG. 27. As a result, the final fuel injection amount Q _fin at the time of stratified combustion is corrected on the increase side based on the injection amount correction coefficient K4. Therefore, even if the virtual intake pressure PMv becomes very small with respect to the predicted intake pressure PMFWD, the output torque of the engine 11 changes slowly in the switching of the combustion system or the like.
[270] This embodiment described above has the following advantages in addition to the advantages of the embodiment of FIGS.
[271] Even when the predicted intake pressure PMFWD and the virtual intake pressure PMv are different at the time of switching the combustion system, it is possible to suitably prevent generation of a step in the engine torque by correction of the fuel injection amount during stratified combustion. This improves runability.
[272] (Example 4)
[273] A fourth embodiment of the present invention will be described with reference to Figs. This embodiment differs from the embodiment of FIGS. 25 to 29 in that the throttle opening degree is corrected based on the predicted intake pressure PMFWD and the virtual intake pressure PMv during homogeneous combustion. In the present embodiment, since the prevention of the step of the engine torque is performed only by the correction of the throttle opening degree, the fuel injection amount control is executed in the same control manner as in the embodiment of Figs. Therefore, only different parts from the respective embodiments of FIGS. 1 to 29 will be described, and detailed descriptions of the same parts as the embodiments of FIGS. 1 to 29 will be omitted.
[274] First, the outline of the throttle opening degree control according to the present embodiment will be described with reference to FIGS. 32 and 33.
[275] In the graph (a) of FIG. 32 and the graph (a) of FIG. 33, the solid line L3 represents the trend of the predicted intake pressure PMFWD with respect to the change of the engine load, and the solid line L4 represents the change of the engine load. The trend of the virtual intake pressure PMv is shown. The predicted intake pressure PMFWD is calculated based on the actual intake pressure PMr and the like, and the virtual intake pressure PMv is calculated regardless of the actual intake pressure PMr and the like.
[276] The graph (a) of FIG. 32 shows an example in which the virtual intake pressure PMv becomes smaller than the predicted intake pressure PMFWD at the time of homogeneous combustion. In this case, for example, the basic fuel injection amount Q _bse at the time of stratified combustion calculated based on the virtual intake pressure PMv at the time of switching the combustion method is calculated at the time of homogeneous combustion calculated based on the predicted intake pressure PMFWD. It _becomes smaller than the basic fuel injection quantity Q _bse . As a result, the engine torque at the time of stratified combustion at the time of switching of the combustion system becomes smaller than the engine torque at the time of homogeneous combustion.
[277] Therefore, according to this embodiment, the target throttle opening degree TAt at the time of homogeneous combustion is closed as shown by the broken line in the graph (b) of FIG. 32 based on the predicted intake pressure PMFWD and the virtual intake pressure PMv. Side is corrected. The fuel injection amount is reduced by the correction, and therefore the engine torque at the time of homogeneous combustion is reduced. This prevents a step from occurring in the engine torque at the time of switching the combustion system, so that the engine torque changes smoothly as shown in the graph (c) of FIG.
[278] The graph (a) of FIG. 33 shows an example in which the virtual intake pressure PMv becomes larger than the predicted intake pressure PMFWD at the time of homogeneous combustion. In this case, for example, the basic fuel injection amount Q _bse at the time of stratified combustion calculated based on the virtual intake pressure PMv at the time of switching the combustion method is calculated at the time of homogeneous combustion calculated based on the predicted intake pressure PMFWD. It _becomes smaller than the basic fuel injection quantity Q _bse . As a result, the engine torque at the time of stratified combustion at the time of switching the combustion system becomes larger than the engine torque at the time of homogeneous combustion.
[279] Therefore, according to this embodiment, the target throttle opening degree TAt at the time of homogeneous combustion is opened as shown by the broken line in the graph (b) of FIG. 33 based on the predicted intake pressure PMFWD and the virtual intake pressure PMv. Side is corrected. The fuel injection amount is increased by the correction, and thus the engine torque at the time of homogeneous combustion is increased. This prevents a step from occurring in the engine torque at the time of switching the combustion system, so that the engine torque changes smoothly as shown in the graph (c) of FIG.
[280] Next, the control procedure of the throttle opening degree is demonstrated with reference to FIG. 30 is a flowchart showing a routine for calculating the target throttle opening degree TAt. The routine is executed in the interruption, for example every predetermined time, via the ECU 92.
[281] In the process of step S1101, the ECU 92 calculates a basic throttle opening degree TA _bse . The basic throttle opening degree TA _bse is calculated based on the accelerator pedal _depressed amount ACCP during homogeneous combustion and based on the basic fuel injection amount Q _bse during stratified combustion. In the process of step S1102, the ECU 92 determines whether the valve instruction mode FMODEB is 1 (homogeneous combustion). If FMODB = 1, the learning value QG2 described below is set as the throttle correction coefficient K5 in the processing of step S1103, and then proceeds to step S1105.
[282] After calculating the target throttle opening degree TAt by multiplying the basic throttle opening degree TA _bse by the throttle correction coefficient K5 in the processing of step S1105, the ECU 92 temporarily terminates the routine. When the target throttle opening degree TAt is calculated in this manner, the ECU 92 controls the drive of the throttle motor 24 based on the signal from the throttle position sensor 44 in a separate process, whereby the throttle The opening degree is controlled by the target throttle opening degree (TAt). Based on the correction of the throttle opening degree by the throttle correction coefficient K5 (learning value QG2), the fuel injection amount is changed so that a suitable engine torque is exerted.
[283] The learning value QG2 is a value which increases or decreases according to the pressure difference DPMK between the predicted intake pressure PMFWD and the virtual intake pressure PMv during homogeneous combustion. That is, the learning value QG2 is set to a large value when the virtual intake pressure PMv is much larger than the predicted intake pressure PMFWD. In this case, the throttle correction coefficient K5 (learning value QG2) increases the target throttle opening TAt at the time of homogeneous combustion. Therefore, since the engine torque at the time of homogeneous combustion is increased, the engine torque changes smoothly even at the time of switching of the combustion mode.
[284] The learning value QG2 is set to a smaller value when the virtual intake pressure PMv is much smaller than the predicted intake pressure PMFWD. In this case, the throttle correction coefficient K5 (learning value QG2) reduces the target throttle opening degree TAt at the time of homogeneous combustion. Thus, since the engine torque at the time of homogeneous combustion is reduced, the engine torque changes smoothly even at the time of switching the combustion mode.
[285] On the other hand, if it is determined in the processing of step S1102 that the valve instruction mode FMODEB is 0 (stratum combustion), the flow proceeds to step S1104. The ECU 92 sets the throttle correction coefficient K5 to 1.0 in the processing of step S1104, and executes the processing of the next step S1105. When the throttle correction coefficient K5 is set to 1.0 at stratified combustion, the throttle opening degree correction based on the coefficient K5 is not executed.
[286] The calculation procedure of the learning value QG2 is demonstrated with reference to FIG. Fig. 31 is a flowchart showing a learning value calculation routine for calculating the learning value QG2. The routine of FIG. 31 differs from the routine of FIG. 28 in the processing of steps S1208 and S1210 corresponding to steps S908 and S910 of FIG. 28. The predetermined value g is added in step S1208 of FIG. 31, while the predetermined value g is subtracted in step S908 of FIG. 28. The predetermined value g is subtracted in step S1210 of FIG. 31, while the predetermined value g is added in step S910 of FIG. 28. The learning value calculation routine of FIG. 31 is also executed in the interruption every predetermined time via the ECU 92.
[287] The processing of steps S1201 to S1205 is for determining whether the operating state of the engine 11 is suitable for the calculation of the learning value QG2. The processing of steps S1201 to S1205 is the same as the processing of steps S901 to S905, and therefore description thereof is omitted.
[288] If the answer of any of the processes of steps S1201 to S1205 is NO, the learning value calculation routine is temporarily terminated, whereas if all the answers are YES, the flow proceeds to step S1206. In the process of step S1206, the ECU 92 calculates the pressure difference DPMK by subtracting the virtual intake pressure PMv from the predicted intake pressure PMFWD. After calculating the pressure difference DPMK, the process proceeds to step S1207. The process after step S1207 is for calculating the learning value QG2 used in the process of step S1103 of FIG. 30 according to the pressure difference DPMK.
[289] In the process of step S1207, the ECU 92 determines whether the pressure difference DPMK is smaller than the predetermined value (-f) (f> 0). If it is determined that DPMK < -f or the virtual intake pressure PMv is much larger than the predicted intake pressure PMFWD, a new value is obtained by adding a predetermined value g to the current learning value QG2 in the process of step S1208. It is set as the learning value QG2, after which the learning value calculation routine is temporarily terminated.
[290] If the virtual intake pressure PMv is much larger than the predicted intake pressure PMFWD, the learning value QG2 gradually increases in the processing of step S1208 in the manner described above. Moreover, the throttle correction coefficient K5 set in accordance with the learning value QG2 also gradually increases in the processing of step S1103 of FIG. As a result, the target throttle opening degree TAt at the time of homogeneous combustion is corrected to the open side based on the throttle correction coefficient K5. The fuel injection amount increases based on the correction of the throttle opening degree, and the engine torque at the homogeneous combustion increases. Therefore, even when the virtual intake pressure PMv becomes very large with respect to the predicted intake pressure PMFWD, the engine torque changes smoothly upon switching of the combustion scheme.
[291] If DPMK <-f in the processing of step S1207, the flow advances to step S1209. In the process of step S1209, the ECU 92 determines whether the pressure difference DPMK is larger than the predetermined value f. If it is determined that DPMK> f or the virtual intake pressure PMv is much smaller than the predicted intake pressure PMFWD, the new learning is subtracted from the current learning value QG2 by the predetermined value g in the processing of step S1210. Value QG2, the learning value calculation routine is then temporarily terminated. If DPMK> f in the processing of step S1209, the learning value calculation routine is also temporarily terminated.
[292] If the virtual intake pressure PMv is much smaller than the predicted intake pressure PMFWD, the learning value QG2 gradually decreases in the processing of step S1210 in the manner described above. Moreover, the throttle correction coefficient K5 set in accordance with the learning value QG2 is also gradually reduced in the processing of step S1103 of FIG. As a result, the target throttle opening degree TAt at the time of homogeneous combustion is corrected to the closing side based on the throttle correction coefficient K5. The fuel injection amount is reduced based on the correction of the throttle opening degree, and the engine torque at the homogeneous combustion is reduced. Therefore, even when the virtual intake pressure PMv becomes very small with respect to the predicted intake pressure PMFWD, the engine torque is gently changed upon switching of the combustion scheme.
[293] This embodiment described above has the following advantages in addition to the advantages of the embodiment of FIGS.
[294] Even when the predicted intake pressure PMFWD and the virtual intake pressure PMv differ from each other at the time of switching of the combustion method, generation of an engine torque step can be prevented by correcting the throttle opening degree during homogeneous combustion. Therefore, the runability is improved.
[295] (Example 5)
[296] A fifth embodiment of the present invention will be described with reference to FIG. This embodiment differs from the respective embodiments of Figs. 1 to 33 in that the virtual throttle opening degree Tav is used to calculate various control values as well as fuel cutoff control. Therefore, the present embodiment will be described only for parts different from the respective embodiments of FIGS. 1 to 33, and detailed descriptions of the same parts as the embodiments of FIGS. 1 to 33 will be omitted.
[297] First, the execution procedure of fuel cutoff control is demonstrated with reference to FIG. The fuel cutoff control is for cutting fuel supplied to the combustion chamber 16 and improving fuel economy when the engine 11 is in a driving state that does not require fuel, such as when the vehicle decelerates. 34 is a flowchart showing a fuel cutoff routine for executing and terminating fuel cutoff based on the engine speed NE and the throttle opening degree TA. The routine is executed at interruptions every predetermined time, for example via the ECU 92.
[298] In the process of step S1301, the ECU 92 determines whether fuel cutoff is currently being executed. If the answer is yes, the processing of steps S1302 to S1304 is executed. If the answer is no, the processing of steps S1305 to S1307 is executed.
[299] The processing of steps S1305 to S1307 is for executing fuel cutoff when the engine speed NE is sufficiently high at the time of deceleration of the vehicle on the downhill. The reason for executing the fuel cut in such a situation is that at the time of deceleration of the vehicle, fuel for actively driving the vehicle is not necessary, and even if the fuel is cut off, the engine speed NE is high and the engine 11 will not stop. Because it is. When the vehicle is going to execute aggressive driving, the load of the engine 11 becomes high, so it can be determined whether the vehicle is decelerated based on whether the engine load is close to zero. In this case, for example, the throttle opening degree TA is used as a value indicating the engine load. It is determined whether or not the vehicle is decelerated based on whether the throttle opening degree TA is smaller than the first opening degree TA1 which is a value slightly larger than zero.
[300] The processing of steps S1302 to S1304 is for terminating the fuel cutoff when the engine speed NE is excessively lowered by the fuel cutoff or when aggressive running is attempted. Whether aggressive running of the vehicle is attempted is determined based on the throttle opening degree TA reaching a second opening degree TA2 which is larger than the first opening degree TA1.
[301] If the fuel cutoff is not executed, the answer in the processing of step S1301 is NO, and the flow proceeds to step S1305. Step S1305 is for judging whether the engine speed NE is sufficiently high so that the engine 11 does not stop even when fuel cut is executed. In the process of step S1305, the ECU 92 determines whether the engine speed NE is equal to or greater than the first speed NE1. The first rotation speed NE1 is equal to the engine rotation speed NE in which the engine 11 does not stop even when fuel cut is executed.
[302] If it is determined in the processing of step S1305 that NE ≧ NE1, the flow advances to step S1306. The processing of step S1306 is for determining whether the engine load has a value approaching zero. In the process of step S1306, the ECU 92 determines whether the throttle opening degree TA is smaller than the first opening degree TA1. If it is determined that TA < TA1 or the value of the engine load is close to zero, the process proceeds to step S1307.
[303] The ECU 92 executes the fuel cut execution process in step S1307, and temporarily terminates the next fuel cut routine. Specifically, the ECU 92 stops the fuel supply to the combustion chamber 16 by controlling the fuel injection valve 40 to start fuel interruption. Even if the answer to either of step S1305 and the processing of step S1306 is no, the fuel cut-off routine is temporarily terminated. In this case, the process of step S1307 is not executed.
[304] When the fuel cutoff is started in the above-described manner, the answer in the processing of step S1301 becomes YES and proceeds to step S1302. The process of step S1302 is for judging whether or not the engine speed NE is excessively lowered. In the process of step S1302, the ECU 92 determines whether the engine rotation speed NE is smaller than the second rotation speed NE2. The second rotation speed NE2 is set to a value smaller than the first rotation speed NE1 and is larger than the value when the engine 11 stops.
[305] If NE < NE2 is determined in the process of step S1302, the flow advances to step S1303. The process of step S1303 is for determining whether the vehicle is actively driving for acceleration or the like, that is, whether the engine load has increased from a value close to zero to a predetermined degree. In the process of step S1303, the ECU 92 determines whether the throttle opening degree TA is equal to or greater than the second opening degree TA2. If it is determined that the value of TA TA2 or the engine load has been increased from 0 to a predetermined degree, the flow proceeds to step S1304.
[306] The ECU 92 executes a fuel cut end process in step S1304, and temporarily terminates the next fuel cut routine. Specifically, the ECU 92 resumes the fuel supply to the combustion chamber 16 by controlling the fuel injection valve 40 to end the fuel cutoff. Even if the answer to either of step S1302 and the processing of step S1303 is no, the fuel cutoff routine ends temporarily. In this case, the process of step S1304 is not executed.
[307] In the judgment processing of step S1306 and step S1303, the actual throttle opening degree TAr is used as the throttle opening degree TA in homogeneous combustion, and the virtual throttle opening degree TAv is the throttle opening in stratified combustion. It is used as the degree TA. As described above, in either case of homogeneous combustion or stratified combustion, the same parameter representing the intake air amount, which is the throttle opening degree TA, is used to determine the engine load. This simplifies experiments and the like to optimize the two thresholds (first opening TA1 and second opening TA2) used to determine engine load. That is, since the optimum first opening degree TA1 and the second opening degree TA2 with respect to the throttle opening degree TA are obtained only by experiments or the like, the parameters used as engine loads differ between stratified combustion and homogeneous combustion. In this case, there is no need to perform an experiment or the like for each parameter.
[308] (Example 6)
[309] A sixth embodiment of the present invention will be described with reference to FIG. This embodiment differs from the respective embodiments of Figs. 1 to 33 in that the virtual throttle opening degree Tav is used for calculation of various control values as well as air conditioner shutoff control. Therefore, the present embodiment will be described only for parts different from the respective embodiments of FIGS. 1 to 33, and detailed descriptions of the same parts as the embodiments of FIGS. 1 to 33 will be omitted.
[310] In the engine 11 of the present embodiment, an air conditioner 45 as an accessory is connected to the crankshaft 14 (see FIG. 1). The air conditioner 45 is connected to the external output circuit 99 of the ECU 92 (see FIG. 2). The air conditioner 45 is driven by the rotation of the crankshaft 14 to air condition the interior of the vehicle. The air conditioner 45 is controlled by the ECU 92. The ECU 92 executes air conditioner cutoff control in accordance with the engine load. This air conditioner cutoff control is for stopping the driving of the air conditioner 45 to provide a high engine output at the time of acceleration of a vehicle requiring a high engine output torque.
[311] An execution procedure of the air conditioner cutoff control will be described with reference to FIG. 35. FIG. 35 is a flowchart showing an air conditioner interruption routine for performing execution and termination of the air conditioner interruption based on the engine speed NE and the throttle opening degree TA. The air conditioning shut-off routine is executed at an interruption every predetermined time, for example, via the ECU 92.
[312] The process of step S1401 is for determining whether a high engine output torque is required. When a high engine output torque is required, such as when the vehicle accelerates, the load of the engine 11 becomes high. Therefore, it is possible to determine whether high engine output torque is required by checking whether the engine load is greater than or equal to a predetermined value. In this case, for example, the throttle opening degree TA is used as a value indicating the engine load. It is judged whether or not a high engine output torque is required, depending on whether the throttle opening degree TA is equal to or greater than a predetermined determination opening degree TA3 close to, for example, a fully open state. That is, the ECU 92 determines whether or not the throttle opening degree TA is equal to or larger than the determination opening degree TA3 in the process of step S1401, and if it is determined that TA TA3, the process proceeds to step S1402.
[313] Step S1402 is for determining whether a request for high engine output torque has been satisfied. When the engine speed NE is a value coinciding with the current throttle opening TA, it is assumed that the demand for high engine output torque is satisfied. In the process of step S1402, the ECU 92 determines whether the engine rotation speed NE is lower than the predetermined determination rotation speed NE3. If it is determined that NE < NE3 or the request for the high engine output torque is not satisfied, the process proceeds to step S1403. The determination speed NE3 is a value of the theoretical engine speed NE obtained when it is assumed that a steady state is provided at the current throttle opening TA.
[314] The ECU 92 executes the air conditioner cutoff process at step S1403, or cuts off the air conditioner 45, and temporarily terminates the routine. When the air conditioner cutoff is executed, there is no loss of the driving force of the engine of the air conditioner 45, and the demand for the high engine output torque is quickly satisfied, so the engine speed NE rises to the determination speed NE3.
[315] If the answer to step S1401 or step S1402 is no, the process proceeds to step S1404. The situation proceeding to step S1404 includes the case where the acceleration of the vehicle ends and the throttle opening degree TA becomes smaller than the determination opening degree TA3, and the engine speed NE is determined by the air conditioner cutoff. It includes the case where it rises to NE3. The ECU 92 executes the termination of the air conditioner cut off or restarts the air conditioner 45 in step S1404, and then temporarily terminates the next routine.
[316] In the judging process of step S1401, the actual throttle opening degree TA is used as the throttle opening degree TA in homogeneous combustion, and the virtual throttle opening degree TAv is the throttle opening degree TA in stratified combustion. Used. As described above, in either case of homogeneous combustion or stratified combustion, the same parameter representing the intake air amount, which is the throttle opening degree TA, is used to determine the engine load (engine output torque). This simplifies the experiment and the like for optimizing the threshold value (decision opening degree TA3) used for determining the engine load (engine output torque). That is, since the optimum judgment opening degree TA3 for the throttle opening degree TA is obtained only by experiments or the like, an experiment or the like is performed for each parameter when the parameter used as the engine load is different between stratified combustion and homogeneous combustion. There is no need to run it.
[317] (Example 7)
[318] A seventh embodiment of the present invention will be described with reference to FIGS. 36 and 37. This embodiment differs from the respective embodiments of Figs. 1 to 33 in that the virtual throttle opening degree (TAv) is used not only for torque-down control during acceleration of the vehicle but also for calculation of various control values. . Therefore, the present embodiment will be described only for parts different from the respective embodiments of FIGS. 1 to 33, and detailed descriptions of the same parts as the embodiments of FIGS. 1 to 33 will be omitted.
[319] In the engine 11 of the present embodiment, ignition timing delay control for delaying the ignition timing is executed as torque reduction control at the time of acceleration. When the ignition timing delay control is executed at the time of acceleration, the torque is reduced at the time of acceleration, thereby preventing the torque shock generated from the acceleration.
[320] The ignition timing delay control procedure will be described with reference to FIG. 37 is a flowchart showing a target ignition timing calculation routine. In the process of step S1601, the ECU 92 calculates a basic ignition timing SA _bse . The basic ignition timing SA _bse is calculated based on the predicted intake pressure PMFWD and the engine speed NE during homogeneous combustion, and the basic fuel injection amount Q _bse and the engine speed NE during stratified combustion. Calculated based on The basic ignition timing SA _bse is used to calculate the target ignition timing SAt in the processing of step S1605 described below. When the target ignition timing SAt is calculated, the ECU 92 controls the actual ignition timing to be the target ignition timing SAt in a separate process.
[321] After the process of step S1601 is executed, the flow advances to step S1602. The process of step S1602 is for determining whether the vehicle is accelerated based on the throttle opening degree TA. That is, the ECU 92 determines whether or not the throttle opening degree TA is equal to or larger than the predetermined determination opening degree TA4 in the process of step S1602. The determination opening degree TA4 is set to a value based on being able to reliably determine whether the vehicle is accelerating. In the processing of step S1602, the actual throttle opening TA is used as the throttle opening TA in homogeneous combustion, and the virtual throttle opening TAv is used as the throttle opening TA in stratified combustion. do.
[322] In the processing of step S1602, if TA≥TA4, the process proceeds to step S1605, and if TA≥TA4, the process proceeds to step S1603. The processing of step S1603 is for determining whether the engine output torque is in a transient state, specifically, whether the increase in engine output torque during acceleration is excessively large. When the increase in engine output torque during acceleration is excessively large, the increase in engine load per unit time increases. Whether the increase of the engine output torque at the time of acceleration is excessively large can be judged by whether the increase amount of the engine load per unit time is more than a predetermined value.
[323] In this case, for example, the throttle opening degree TA is used as a value indicating the engine load. Whether the increase of the engine output torque at the time of acceleration is excessively large or not is judged according to whether the change amount (ΔTA) of the engine load per unit time is equal to or larger than the predetermined determination value (ΔTA5). That is, the ECU 92 judges whether or not the change amount ΔTA is equal to or larger than the determination value ΔTA5 in the processing of step S1603, and if it is determined that ΔTA ≥ ΔTA5, the process goes to step S1604. Proceed.
[324] In the processing of step S1603, the amount of change in the actual throttle opening degree TAr per unit time is used as the change amount ΔTA in the homogeneous combustion, and the virtual throttle opening degree Tav per unit time is used in the stratified combustion. It is used as the change amount (ΔTA) of. As described above, in either of the homogeneous combustion or the stratified combustion, the same parameter representing the intake air amount, which is the change amount of the same parameter per unit time, is used to determine the transient state of the engine load (engine output torque). This simplifies the experiment and the like for optimizing the threshold value (judge value TA5) used to determine the transient state of the engine load (engine output torque). That is, since the optimum determination value ΔTA5 for the change amount ΔTA of the throttle opening TA per unit time is obtained only by experiments or the like, in the case where the parameter used as the engine load is different between stratified combustion and homogeneous combustion, There is no need to run an experiment or the like for each parameter of.
[325] When proceeding to step S1604 as described above, the ECU 92 sets the ignition timing delay amount K6 used in the processing of step S1605 to be described below to a predetermined value δ. The ECU 92 calculates the target ignition timing SAt by adding the delay amount K6 to the basic ignition timing SA _bse in the processing after step S1605, and temporarily terminates the next routine. If the answer to step S1602 or step S1603 is no, then the processing of step S1605 is executed without passing through step S1604, after which the routine ends temporarily.
[326] If the delay amount K6 is set to the predetermined value δ in the process of step S1604, the target ignition timing SAt is delayed by the predetermined value δ in step S1605 and the delay control of the ignition timing is executed. do. By performing this delay control of the ignition timing, torque reduction during acceleration can be provided, and torque shocks generated due to excessive increase in engine output torque during acceleration can be generated. In the delay control of the ignition timing, the ignition timing is temporarily delayed by the delay amount K6 (predetermined value δ), and the next delay amount K6 is gradually approached to zero, so that the ignition timing is gradually restored to its original state. Is returned.
[327] The procedure for returning the delayed ignition timing to its original state will be described with reference to FIG. 36 is a flowchart showing a delay amount reduction processing routine for gradually bringing the delay amount K6 close to zero. The flowchart is executed at interruptions every predetermined time, for example, via the ECU 92.
[328] In the process of step S1501, the ECU 92 sets a value obtained by subtracting the predetermined value γ from the current delay amount K6 as a new delay amount K6. The delay amount K6 is gradually reduced by the processing of step S1501. In the processing of the next step S1502, the ECU 92 determines whether the delay amount K6 is less than zero, and if K6 <0, temporarily terminates the routine. If K6 <0, the delay amount K6 is set to zero in the processing of step S1503, after which the routine ends temporarily. As described above, after the predetermined value δ is set, the delay amount K6 gradually decreases and remains at zero after reaching zero.
[329] Each embodiment can be modified as follows.
[330] A valve characteristic variable mechanism other than the valve timing variable mechanism 27, such as a valve lift amount variable mechanism for changing the valve lift amount of the intake valve 19, may be provided in the engine 11 of FIG. In this case, it is suitable to calculate the virtual intake pressure PMv in consideration of the change of the valve characteristic of the intake valve 19 by the valve rise amount variable mechanism.
[331] The present invention can be applied to the engine 11 in which the valve timing variable mechanism 27 is not provided. In this case, since the valve timing of the intake valve 19 does not need to be taken into account in calculating the virtual intake pressure PMv, the control load of the ECU 92 is reduced.
[332] In order to calculate the final fuel injection amount Q _fin , a parameter indicating an intake amount other than the intake pressure, which is, for example, the intake amount itself, may be used.
[333] The invention is applicable to engines that switch between four types of combustion schemes: stratified combustion, light stratified combustion, homogeneous lean combustion, and homogeneous stoichiometric combustion. In this case, the mode correction coefficient K _mode is set to a different value for each combustion system. That is, in the combustion system with a large air-fuel ratio of the air-fuel mixture, the mode correction coefficient K _mode is set to a small value. Homogeneous lean combustion is a combustion method in which the air-fuel mixer is combusted at an air-fuel ratio larger than the theoretical air-fuel ratio, with the fuel in the air-fuel mixer uniformly mixed with air. Weak stratified combustion is an intermediate form of homogeneous lean and stratified combustion.
[334] 17 to 24, the injection quantity correction coefficient K1 is calculated based on the difference between the predicted intake pressure PMFWD and the virtual intake pressure PMv, and the injection quantity correction coefficient K1 is gradually increased to 1.0. Can be approached. In this case, since the injection amount correction coefficient K1 is returned to 1.0, even when the difference between the predicted intake pressure PMFWD and the virtual intake pressure PMv differs depending on the operating region of the engine 11, the fuel injection amount correction This can prevent the step from occurring in the engine torque.
[335] The rate of change when the injection quantity correction coefficient K1 is gradually approached to 1.0 may be changed depending on, for example, the difference between the predicted intake pressure PMFWD and the virtual intake pressure PMv. In this case, generation | occurrence | production of the level | step difference to engine torque can be prevented more suitably.
[336] 17 to 24, the rate of change when the ignition timing correction amount K2 and the throttle opening correction amount K3 are gradually approached to zero is more suitably prevented from generating a step in engine torque. It may vary according to the difference between the predicted intake pressure PMFWD and the virtual intake pressure PMv. In this case, the predetermined value a2 used in the process of step S508 of FIG. 20 and the predetermined value a3 used in the process of step S608 of FIG. 23 are the predicted intake pressure PMFWD and the virtual intake pressure ( Change according to the difference between PMv).
[337] In the embodiment of Figs. 17 to 24, although the ignition timing and the throttle opening are corrected to remove the step of the engine torque, fuel injection amount correction can be performed instead of or in addition to the correction, whereby the engine Remove the torque step.
[338] 17 to 24, the switching delay counter C may be set to a fixed value.
[339] The virtual throttle opening (TAv) can be used for transmission control, automatic driving control to keep the vehicle speed constant, or so-called VSC control for preventing slip of the wheels and the like. In place of the virtual throttle opening TAv, the virtual intake pressure PMv can be used for various types of engine control as a value representing the engine load.

权利要求:
Claims (17)
[1" claim-type="Currently amended] A control apparatus of an engine powered by burning a mixture of air and fuel in a combustion chamber, the engine having an accelerator pedal and a throttle valve for adjusting the intake air amount into the combustion chamber, wherein the engine is provided between homogeneous combustion and stratified combustion. In the control device of the engine capable of switching the combustion system of,
Control means for controlling the engine in accordance with the load acting on the engine;
Calculation means for calculating, as a virtual parameter, a value corresponding to a parameter when homogeneous combustion is executed in the operation amount of the accelerator pedal when stratified combustion is executed,
The control means uses a parameter representing an intake air amount as a value representing an engine load when homogeneous combustion is executed,
And the control means uses the virtual parameter as a value representing an engine load when stratified combustion is executed.
[2" claim-type="Currently amended] 2. An engine control apparatus according to claim 1, wherein said calculating means calculates said virtual parameter in consideration of a response delay of said parameter with respect to an operation amount of an accelerator pedal when homogeneous combustion is executed.
[3" claim-type="Currently amended] The control value according to claim 1 or 2, wherein the control means calculates a control value set according to the engine load based on the parameter when homogeneous combustion is executed, and based on the virtual parameter when stratified combustion is executed. And controlling the engine based on the calculated control value.
[4" claim-type="Currently amended] 4. An engine control apparatus according to claim 3, wherein the control value is a fuel injection amount.
[5" claim-type="Currently amended] 5. An engine control apparatus according to claim 4, wherein the control means calculates the fuel injection amount in consideration of the difference between fuel economy in stratified combustion and fuel efficiency in homogeneous combustion.
[6" claim-type="Currently amended] 6. An engine control apparatus according to claim 5, wherein said control means corrects said calculated fuel injection amount based on atmospheric pressure.
[7" claim-type="Currently amended] 4. The method of claim 3, wherein the parameter is obtained based on an actual measured value, wherein a difference between the parameter and the virtual parameter corresponds to a difference between engine torque in homogeneous combustion and engine torque in stratified combustion, The control means further comprises correction means for correcting the control value to eliminate the difference between the respective engine torques of the combustion schemes.
[8" claim-type="Currently amended] 8. The engine control according to claim 7, wherein the correction means corrects the control value based on a difference between the parameter and the virtual parameter when the combustion mode is switched between homogeneous combustion and stratified combustion. Device.
[9" claim-type="Currently amended] 8. The method according to claim 7, wherein the correction means, when homogeneous combustion is executed, calculates a virtual parameter based on an operation amount of the accelerator pedal in addition to the parameter, and based on the difference between the calculated virtual parameter and the parameter. The control device of the engine, characterized in that for correcting the control value.
[10" claim-type="Currently amended] The method according to claim 1 or 2, wherein the control means determines whether the parameter is greater than a predetermined threshold when homogeneous combustion is executed, and whether the virtual parameter is greater than a predetermined threshold when stratified combustion is executed. And determining whether to control the engine based on the result of the determination.
[11" claim-type="Currently amended] 3. An accessory according to claim 1 or 2, wherein an accessory driven by the engine is connected to the engine,
The control means determines whether the parameter is greater than a predetermined threshold when homogeneous combustion is executed, and determines whether the virtual parameter is greater than a predetermined threshold when stratified combustion is executed, and the result of the determination Controlling the accessory based on the control device of the engine.
[12" claim-type="Currently amended] The method according to claim 1 or 2, wherein the control means determines whether the amount of change of the parameter is greater than a predetermined threshold when homogeneous combustion is executed, and the amount of change of the virtual parameter is predetermined when stratified combustion is executed. Determining whether the value is larger than a threshold value, and controlling the engine based on a result of the determination.
[13" claim-type="Currently amended] The virtual throttle opening degree according to claim 1 or 2, wherein the parameter is a throttle opening degree indicating an opening degree of the throttle valve, and the calculating means determines the virtual throttle opening degree based on an operation amount of an accelerator pedal when stratified combustion is performed. It calculates as a parameter, The control apparatus of the engine characterized by the above-mentioned.
[14" claim-type="Currently amended] 3. The intake pressure according to claim 1 or 2, wherein the parameter is an intake pressure representing the pressure of air sucked into the combustion chamber, and the calculating means uses the virtual intake pressure as the virtual parameter based on an accelerator pedal operation amount when stratified combustion is executed. The control apparatus of the engine characterized by the above-mentioned.
[15" claim-type="Currently amended] 15. The throttle valve according to claim 14, wherein the calculating means calculates the opening degree of the throttle valve as the virtual throttle opening degree when the homogeneous combustion is performed at the operation amount of the accelerator pedal when stratified combustion is performed, and based on the virtual throttle opening degree. And calculates the virtual intake pressure as well.
[16" claim-type="Currently amended] 15. The engine of claim 14, wherein the engine has an intake valve and a variable mechanism for changing valve characteristics of the intake valve,
The calculating means calculates the valve characteristic as a virtual valve characteristic when homogeneous combustion is executed from the operation amount of the accelerator pedal when stratified combustion is executed, and calculates a virtual intake pressure in consideration of the virtual valve characteristic. controller.
[17" claim-type="Currently amended] A control method of an engine that obtains power by burning a mixture of air and fuel in a combustion chamber, the engine having an accelerator pedal and a throttle valve for adjusting the amount of air intake into the combustion chamber, wherein the engine is provided between homogeneous combustion and stratified combustion. In the engine control method, it is possible to switch the combustion system of
Controlling the engine according to the load acting on the engine;
When the homogeneous combustion is carried out, using the parameter representing the intake air amount as a value representing the engine load,
Calculating, as a virtual parameter, a value corresponding to the parameter when homogeneous combustion is executed in the operation amount of the accelerator pedal when stratified combustion is executed, and
And when stratified combustion is executed, using the virtual parameter as a value representing engine load.

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同族专利:

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公开号 | 公开日

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EP1143130A1|2001-10-10|

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ES2381564T3|2012-05-29|

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JP3259712B2|2002-02-25|

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WO2000042306A1|2000-07-20|

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EP1143130B1|2012-03-14|

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CN1336984A|2002-02-20|

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EP1143130A4|2009-09-02|

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JP2000297688A|2000-10-24|

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KR100448300B1|2004-09-14|

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US6510835B1|2003-01-28|

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CN1124407C|2003-10-15|

引用文献:

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公开号 | 申请日 | 公开日 | 申请人 | 专利标题

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法律状态:
1999-01-12|Priority to JPJP-P-1999-00005362

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1999-01-12|Priority to JP536299

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1999-02-10|Priority to JP3289499

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1999-02-10|Priority to JPJP-P-1999-00032894

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1999-05-25|Priority to JPJP-P-1999-00145492

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1999-05-25|Priority to JP14549299A

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2000-01-11|Application filed by 사이토 아키히코, 도요타지도샤가부시키가이샤

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2000-01-11|Priority to PCT/JP2000/000067

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2002-01-17|Publication of KR20020005573A

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2004-09-14|Application granted

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2004-09-14|Publication of KR100448300B1

优先权:

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申请号 | 申请日 | 专利标题

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JPJP-P-1999-00005362|1999-01-12|

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JP536299|1999-01-12|

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JP3289499|1999-02-10|

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JPJP-P-1999-00032894|1999-02-10|

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JPJP-P-1999-00145492|1999-05-25|

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JP14549299A|JP3259712B2|1999-01-12|1999-05-25|Control device for internal combustion engine|

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PCT/JP2000/000067|WO2000042306A1|1999-01-12|2000-01-11|Device and method for controlling engines|