System and method to prevent unwanted braking of a hybrid vehicle

专利摘要:
A system and method to prevent torque to be applied to the vehicle wheels in a direction opposite the vehicle's movement should the electric traction motor of the hybrid vehicle fail in such a way that rotati on of the rotor with respect to the stator is prevented or hindered is described herei n. The system includes two traction power sources can be used in parallel to power the wheels of the vehicle. Accordingly, should such an unwanted torque be detected from one of the traction power source, the other traction power source is energized and so controlled as to apply a compensating torque to cause the wheels to be freewheeling and therefore allow the driver to exit t he road safely.
公开号:CA2549974A1
申请号:C002549974
申请日:2006-06-13
公开日:2007-01-13
发明作者:Ghislain Lambert；Karl Brazeau；Jean-Marc Cyr；Maalainine El Yacoubi
申请人:TM4 Inc；
IPC主号:B60W20-00

专利说明:
[1" class="description-paragraph] TITLE OF THE INVENTION System and method to prevent unwanted braking of a hybrid vehicle FIELD OF THE INVENTION[0001] The present invention relates to hybrid vehicles. More specifically, the present invention is concerned with a system and method to prevent unwanted braking of a hybrid vehicle. BACKGROUND OF THE INVENTION
[2" class="description-paragraph] [0002] Hybrid vehicles are well known in the art. They are usually provided with an electric traction motor and a second power source such as an internal combustion engine (ICE) and a generator used to supply electricity to the electric motor and/or to recharge batteries of the vehicle.
[3" class="description-paragraph] [0003] On the one hand, a hybrid vehicle is said to be a series hybrid vehicle when the electric traction motor is used to drive the traction wheels and the ICE is exclusively used to drive the generator to recharge the vehicle's batteries and/or supply electric power to the electric traction motor.
[4" class="description-paragraph] [0004] On the other hand, a hybrid vehicle is said to be a parallel hybrid vehicle when both the electric traction motor and the ICE may be used simultaneously or individually to drive the wheels of the vehicle. In parallel hybrid vehicles, the ICE may also be used to recharge the batteries through a generator.
[5" class="description-paragraph] [0005] Series/parallel hybrid vehicles (SPHV) are also known in the art. Conventionally, these vehicles may be switched between a series mode and a parallel mode, as described hereinabove.
[6" class="description-paragraph] [0006] Generally, in all these types of hybrid vehicles, the electric traction motor is directly connected to the traction wheels of the vehicle. This may cause a problem should a malfunction of the electric traction motor cause it to fail in such a way that the rotor is prevented from rotating with respect to the stator. If this happens, the consequence of the malfunction may be viewed as a torque applied on the traction wheels in the direction opposite the movement of the vehicle. This torque may be dangerous, especially if only one traction wheel is affected.
[7" class="description-paragraph] [0007] There is therefore a need to provide a system and method to prevent such an unwanted torque opposite the vehicle's direction. OBJECTS OF THE INVENTION
[8" class="description-paragraph] [0008] An object of the present invention is therefore to provide a system and method to prevent unwanted braking of a hybrid vehicle.
[9" class="description-paragraph] [0009] Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of preferred embodiments thereof, given by way of example only with reference to the accompanying drawings.
[10" class="description-paragraph] [0010] It is to be noted that the expression "hybrid vehicle" is to be construed herein as a vehicle having at least two traction power sources, these power sources being of the same type, for example finro electric motors, or of different types, for example an electric motor and an ICE. BRIEF DESCRIPTION OF THE DRAWINGS
[11" class="description-paragraph] [0011] In the appended drawings:
[12" class="description-paragraph] [0012] Figure 1 is a general block diagram of a method according to an embodiment of the present invention;
[13" class="description-paragraph] [0013] Figure 2 is a schematic view of a series hybrid drive system according to an embodiment of the present invention, shown in a purely electric mode where only the traction motor contributes to the propulsion;
[14" class="description-paragraph] [0014] Figure 3 is a schematic view similar to Figure 2 but showing the drive system in a purely electric mode where both the traction motor and the electric generator contribute to the propulsion; and
[15" class="description-paragraph] [0015] Figure 4 is a schematic view of a parallel hybrid drive system where a planetary transmission interconnects the ICE, the traction motor and the wheels. DETAILED DESCRIPTION
[16" class="description-paragraph] [0016] Generally stated, the present invention is concerned with a system and method to prevent torque to be applied to the vehicle wheels in a direction opposite the vehicle's movement should the electric traction motor of the hybrid vehicle fail in such a way that rotation of the rotor with respect to the stator is prevented or hindered. More specifically, the hybrid vehicle is so configured that finro traction power sources can be used in parallel to power the wheels of the vehicle. Accordingly, should such a unwanted torque be detected from one of the traction power source, the other traction power source is energized and so controlled as to apply a compensating torque to cause the wheels to be freewheeling and therefore allow the driver to exit the road safely.
[17" class="description-paragraph] [0017] Turning now to Figure 1 of the appended drawings, a block diagram generally illustrating a method according to an aspect of the present invention will be described.
[18" class="description-paragraph] [0018] The method starts at step 10, then immediately proceeds to verify if a failure of one of the two traction generator is detected (step 12). There are many ways to detect such a failure
[19" class="description-paragraph] [0019] In a first example, the traction generators are usually provided with rotation sensors that supply the rotation speed data to a central controller. Therefore, should a quick rotation speed change be detected without being requested by the driver, the controller would then determine that a traction generator has failed. Of course, specialized sensors could be installed on the traction generators or directly on the wheels to detect failure; or the electric power supplied to the traction generators could be monitored to detect failure.
[20" class="description-paragraph] [0020] In a second example, the vehicle's controller could be so designed as to detect, in real time, phase imbalance on the traction generators. When such a phase imbalance is detected, the controller determines that the traction generator is unwillingly braked or otherwise failed and can take action.
[21" class="description-paragraph] [0021] If no failure is detected, the method loops back to step 12. In other words, detection of the failure of the traction generators is constantly done.
[22" class="description-paragraph] [0022] If a failure is detected in step 12, the method then branches to step 14 and engages the other traction generator of the hybrid vehicle. Of course, should the other traction generator be already engaged, step 14 is omitted.
[23" class="description-paragraph] [0023] Finally, the method controls, in step 16, the other traction generator so that a counteracting torque is generated to place the driving wheels of the vehicle in a freewheeling state. Many ways can be used to so control the other traction generator.
[24" class="description-paragraph] [0024] As a first example, one could calculate the braking torque, i.e.the torque in the direction opposite the desired direction, by knowing the current of each phase of the faulty traction generator, the speed of the vehicle and the traction generator angular position.
[25" class="description-paragraph] [0025] As a second example, the operational traction generator could be supplied a torque that is equal to the sum of the torque requested by the user and a compensation torque that would be a function of the actual speed of the faulty traction generator and the type of fault detected.
[26" class="description-paragraph] [0026] Turning now to Figure 2 of the appended drawings, there is provided a hybrid drive train 20 to which an ICE 22, a battery 24 and wheels (only one shown) of the vehicle may be directly or indirectly connected.
[27" class="description-paragraph] [0027] The drive train 20 includes two traction generator in the form of a traction motor 26 and an electric generator 28; a three-position clutch 30 a disk actuating mechanism 31 and a controller 32 connected to the ICE 22, the battery 24, the traction motor 26, the electric generator 28 and the disk actuating mechanism 21. The controller 32 may thus control the entire drive train 20 and send and receive data about the operational state of the ICE 22 and the state of charge of the battery 24.
[28" class="description-paragraph] [0028] The three position clutch 30 includes a first disk 34 connected to the shaft of the ICE 22, a second disk 36 connected to the shaft of the traction motor 26 and a movable disk 38 connected to the shaft of the electric generator 28. A first position (not shown) of the clutch connects the movable disk 38 to the first disk 34; in a second position (Figure 3) the movable disk is connected to the second disk 36 and in a third position (Figure 2) the movable disk 38 is freewheeling. The disk actuating mechanism 31 is controlled by the controller 32 and includes mechanical elements (not shown) to move the movable disk 38 between its three above-noted positions. The disk moving arrangement may operate via magnetism, a fork or a solenoid, for example.
[29" class="description-paragraph] [0029] It is to be noted that Figure 2 is very schematic. Many other components are required to operate the drive train 20. For example, the controller 32 includes power electronics (not shown). Similarly, the battery 24, the traction motor 26 and the electric generator 28 all include different sensors to supply data to the controller 32.
[30" class="description-paragraph] [0030] Figure 2 shows the drive train 20 in a neutral state, i.e. that the shaft of electric generator 28, connected to the movable disk 38, is freewheeling. The drive train 20, when in a neutral state is configured as a purely electric drive train, i.e. that ICE is not part of the operational drive train.
[31" class="description-paragraph] [0031] It is to be noted that when the movable disk 38 is connected to the first disk 34 (not shown), the drive train 20 is in a serial hybrid configuration since the ICE is used to power the electric generator 28 to thereby generate electric current and the traction motor 26 is used to provide traction.
[32" class="description-paragraph] [0032] Turning now to Figure 3 of the appended drawings, the drive train 20 is shown in a state where, the movable disk 38 is brought into contact with the second disk 36, therefore linking the shaft of the electric generator and the shaft of the traction motor 26. The electric generator 28 is then used in a motor mode and may generate mechanical power and transfer this mechanical power to the shaft of the traction motor and therefore to the wheels 25 of the vehicle.
[33" class="description-paragraph] [0033] The controller 32 of the drive train 20 may thus be configured as to execute the method described hereinabove and control the clutch 30 accordingly to link the electric generator 28 and the traction motor 26 should failure be detected in the traction motor 26.
[34" class="description-paragraph] [0034] Optionally, the operation of the electric generator 28 is monitored by the controller 32 to automatically place the clutch 30 in the neutral state illustrated in Figure 2 should failure of the generator 28 be detected while the clutch 30 is not in the neutral state.
[35" class="description-paragraph] [0035] Figure 4 illustrates a parallel hybrid drive train 40 is provided with an ICE 42, an electric traction motor 44, a controller 46, a battery 48 and a planetary transmission 50 interconnecting the ICE 42 and the traction motor 44 to wheels 52 (only one shown) of the vehicle.
[36" class="description-paragraph] [0036] One skilled in the art will easily understand that the parallel hybrid drive train 40 of Figure 4 is well suited to incorporate the principles of the present invention. Indeed, since both the ICE 42 and the traction motor 44 are ,, interconnected via the planetary transmission 50, the IGE may generate a torque to counteract the torque in the opposite direction caused by the failure of the traction motor, should this happen.
[37" class="description-paragraph] [0037] Even though the above description is concerned with a hybrid vehicle provided with two traction generators, more that two distinct traction generators could be provided and the controller could be configured to detect the failure of any of the traction generators and act accordingly.
[38" class="description-paragraph] [0038] Although the present invention has been described hereinabove by way of preferred embodiments thereof, it can be modified, without departing from the spirit and nature of the subject invention.

权利要求:
Claims (2)
[1] 1. A method to detect and correct the failure of an electric traction generator of a hybrid vehicle comprising two electric traction generators able to supply torque to the wheels of the vehicle; the method comprising:detecting the failure of one of the two electric traction generators;engaging the other of the two electric traction generators;control the other of the two electric traction generators so that it generates an adequate torque to counteract the effect of the one failed electric traction generator.
[2] 2. A system to detect and correct the failure of an electric traction generator of a hybrid vehicle comprising two electric traction generators able to supply torque to the wheels of the vehicle; the system comprising:means for detecting the failure of one of the two electric traction generators;means for engaging the other of the two electric traction generators;means for control the other of the two electric traction generators so that it generates an adequate torque to counteract the effect of the one failed electric traction generator.

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同族专利:

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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:
2011-06-13| FZDE| Dead|

优先权:

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申请号 | 申请日 | 专利标题

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US69847305P| true| 2005-07-13|2005-07-13||

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US60/698,473||2005-07-13||

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