• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a length-adjustable connecting rod for an internal combustion engine having a first and second connecting rod, which are adjustable relative to each other with at least one cylinder-piston unit, wherein the cylinder-piston unit, a cylinder bore, a longitudinally movably arranged adjusting piston, a piston rod and at least one provided in the cylinder bore first pressure chamber for receiving engine oil, which is bounded on one side by the movable adjusting piston has. According to the invention, the cylinder-piston unit comprises a first and a second interface, the piston rod is formed integrally with the adjusting piston and connected via the first interface of the cylinder-piston unit with the first connecting rod, the cylinder bore has an integral upper stop for the adjusting piston on and the cylinder bore is connected via the second interface of the cylinder-piston unit with the second connecting rod part, wherein the first interface of the cylinder-piston unit is a purely mechanical and the second interface is a mechanical and a hydraulic interface. Furthermore, the invention relates to assembly methods and the use of such a connecting rod in an internal combustion engine and an internal combustion engine.
    公开号:AT519292A2
    申请号:T50925/2017
    申请日:2017-11-03
    公开日:2018-05-15
    发明作者:Kai Arens Dr；Riba Zóltan；Bodensteiner Martin；Latz Steffen；Heller Malte
    申请人:Avl List Gmbh；Iwis Motorsysteme Gmbh & Co Kg；
    IPC主号:
    专利说明:

    Connecting rod with adjustment mechanism between connecting rod and connecting rod
    The present invention relates to a length-adjustable connecting rod for an internal combustion engine, in particular a gasoline engine, with a first Pleuelteil and a second Pleuelteil, wherein the first Pleuelteil relative to the second Pleuelteil is movable to adjust the length of the connecting rod and at least one by means of engine oil of the internal combustion engine hydraulically actuated cylinder-piston unit to move the first Pleuelteil relative to the second Pleuelteil, the cylinder-piston unit comprises a cylinder bore, a long in the cylinder bore arranged adjusting piston, a piston rod and at least one provided in the cylinder bore first pressure chamber to Inclusion of engine oil, which is bounded on one side by the movable adjusting piston. Furthermore, the invention relates to an internal combustion engine with such a connecting rod, the use of such a connecting rod in an internal combustion engine and a method for mounting the length-adjustable connecting rod.
    The thermal efficiency of an internal combustion engine, especially in gasoline engines, is dependent on the compression ratio ε, d. H. the ratio of the total volume before compression to the compression volume (ε = (stroke volume Vh + compression volume Vc) / compression volume Vc). As the compression ratio increases, the thermal efficiency increases. The increase in the thermal efficiency via the compression ratio is degressive, but still relatively strong in the range of today's usual values.
    In practice, the compression ratio can not be increased arbitrarily, since too high a compression ratio leads to unintentional spontaneous combustion of the combustion mixture due to pressure and temperature increase. This early combustion not only leads to a troubled run and the so-called knocking in gasoline engines, but can also lead to component damage to the engine. In the partial load range, the risk of spontaneous combustion, which depends not only on the influence of ambient temperature and pressure but also on the operating point of the engine, is lower. Accordingly, a higher compression ratio is possible in the partial load range. In the development of modern internal combustion engines, there are therefore efforts to adjust the compression ratio to the respective operating point of the engine. For the realization of a variable compression ratio (VOR) there are different solutions with which the position of the crank pin or the piston pin of the engine piston changes or the effective length of the connecting rod is varied. There are always solutions for a continuous and discontinuous adjustment of the components. Continuous adjustment allows optimal reduction of CO 2 emissions and consumption due to a compression ratio that can be set for each operating point. In contrast, a discontinuous adjustment with two trained as end stops the adjustment stages design and operational advantages and still allows compared to a conventional crank mechanism significant savings in consumption and CO 2 emissions.
    Already the document US 2,217,721 describes an internal combustion engine with a length-adjustable connecting rod with two telescopically displaceable connecting rods, which together form a high-pressure chamber. For filling and emptying of the high-pressure chamber with engine oil and thus to change the length of the connecting rod, a hydraulic adjusting mechanism is provided with a control valve with spring-biased closure element, which is displaceable by the pressure of the engine oil in an open position.
    A discontinuous adjustment of the compression ratio for an internal combustion engine is shown in EP 1 426 584 A1, in which an eccentric connected to the piston pin makes it possible to adjust the compression ratio. In this case, a fixation of the eccentric in one or the other end position of the pivoting area by means of a mechanical locking.
    DE 10 2005 055 199 A1 likewise discloses the mode of operation of a length-variable connecting rod with which different compression ratios are made possible. The realization is also done here via an eccentric in the small connecting rod, which is fixed in position by two hydraulic cylinders with variable resistance.
    WO 2013/092364 A1 describes a length-adjustable connecting rod for an internal combustion engine with two telescopically movable rod parts, wherein a rod part forms a cylinder and the second rod part forms a longitudinally displaceable piston element. Between the adjusting piston of the first rod part and the cylinder of the second rod part, a high-pressure space is formed, which is supplied via an adjusting mechanism with an oil passage and an oil pressure-dependent valve with engine oil.
    A similar length-adjustable connecting rod for an internal combustion engine with telescopically displaceable rod parts is shown in WO 2015/055582 A2. According to WO 2015/055582 A2, the compression ratio in the internal combustion engine should be adjusted by the connecting rod length. The connecting rod length affects the compression volume in the combustion chamber, wherein the stroke volume is determined by the position of the crankshaft journal and the cylinder bore. A short connecting rod therefore leads to a lower compression ratio than a long connecting rod with otherwise the same geometric dimensions, such as piston, cylinder head, crankshaft, valve control, etc. The connecting rod length is hydraulically varied between two positions. The entire connecting rod is made of several parts, wherein the change in length is effected by a telescopic mechanism with a double-acting hydraulic cylinder. The small connecting rod eye, usually for receiving the piston pin, is connected to a piston rod (telescopic rod part). The associated adjusting piston is axially displaceably guided in a cylinder which is arranged in the connecting rod part with the large connecting rod eye, usually for receiving the crankshaft journal. The adjusting piston separates the cylinder into two pressure chambers, an upper and a lower pressure chamber. These two pressure chambers are supplied with engine oil via check valves, whereby the supply of engine oil takes place via the lubrication of the connecting rod bearing. For this purpose, an oil passage from the crankshaft journal over the connecting rod bearing to the connecting rod and there via the check valves in the pressure chambers is required. If the connecting rod is in the long position, there is no engine oil in the upper pressure chamber. The lower pressure chamber, however, is completely filled with engine oil. During operation, the connecting rod is loaded alternately due to the gas and inertial forces on train and pressure. In the long position of the connecting rod, a tensile force is absorbed by the mechanical contact with an upper stop of the adjusting piston. The connecting rod length does not change as a result. An applied compressive force is transmitted via the piston surface to the oil-filled lower pressure chamber. Since the check valve of this pressure chamber prevents oil return, the oil pressure rises, whereby pressures of well over 1,000 bar can occur in the lower pressure chamber. The connecting rod length does not change. The connecting rod is hydraulically locked in this direction. In the short position of the connecting rod, the conditions turn around. The lower pressure chamber is empty, the upper pressure chamber is filled with engine oil. A tensile force causes a pressure increase in the upper pressure chamber. A compressive force is absorbed by a mechanical stop. The connecting rod length can be adjusted in two stages by emptying one of the two pressure chambers. Here, one of the two inlet check valves is bridged by an associated return channel. Engine oil can flow through these return passages independently of the pressure difference between the pressure chamber and the supply device. The respective check valve loses its effect accordingly. The two return channels are opened and closed by a control valve, always exactly one return channel open, the other is closed. The actuator for switching the two return channels is controlled hydraulically by the supply pressure here.
    The space for such a length-adjustable connecting rod is limited both axially and radially. In the crankshaft direction of the space is limited by the bearing width and the distance of the counterweights. In the axial direction, only the space between the small connecting rod eye for supporting the piston pin and the large connecting rod eye for supporting the crankshaft journal and a possible Verstellhub the connecting rod is anyway available.
    The forces to be transmitted by a connecting rod in an internal combustion engine are considerable, which is why the pressures in the pressure chambers of the cylinder-piston unit can be considerable. In view of the high internal pressures in such a cylinder-piston unit, the fatigue strength of the materials used is problematic, but also the construction of the components in view of the small installation space.
    In the above-mentioned WO 2015/055582 A2, the cylinder bore is formed in the second connecting rod part, while the first connecting rod part is connected to a piston rod of the adjusting piston. The second connecting rod part must therefore be made relatively expensive in order to obtain the cylinder bore with the desired precision and good wear resistance.
    It is therefore the object of the present invention to provide a length-adjustable connecting rod, which allows easy manufacture and ensures a long service life.
    For this purpose, the invention provides that the cylinder-piston unit comprises a first and a second interface, the piston rod is formed integrally with the adjusting piston and is connected via the first interface of the cylinder-piston unit with the first connecting rod, the cylinder bore an integral has upper stop for the adjusting piston and the cylinder bore is connected via the second interface of the cylinder-piston unit with the second connecting rod part and wherein the first interface of the cylinder-piston unit is a purely mechanical interface and the second interface of the cylinder-piston Unit is a mechanical and a hydraulic interface. Usually, the adjusting piston and the cylinder bore of the cylinder-piston unit are rotationally symmetrical, but not limited to such a geometric shape. A length-adjustable connecting rod according to the present invention also includes oval, polygonal or other cross-sectional shapes of the adjusting piston and the cylinder bore of the cylinder-piston unit.
    Due to the design of the cylinder bore and the upper stop as a component, the upper stop is very robust. The connection between the first Pleuelteil with the connecting rod and the piston rod is very accessible from the outside, so that a simple production of the connection between the first Pleuelteil and the piston rod is possible and this connection can be easily controlled. The connection between the second connecting rod (big end) and the cylinder bore is very accessible from the outside. Thus, here is a simple production and control possible. Since the upper stopper is integrally formed with the cylinder bore, the cylinder bore, the upper stop and a rod guide for the piston rod can be made well coaxially by the upper stopper. The piston and the piston rod can also be manufactured well coaxial, so that overall tight tolerances are possible. As a result, the guide between the adjusting piston and the cylinder bore is improved, so that less wear occurs. The first interface connects the piston rod and thus the cylinder-piston unit with the first connecting rod. The connection at the first interface is a purely mechanical connection and can be done for example by adhesion, positive connection or material connection. At this interface, the tensile and compressive forces occurring during operation of the engine on the connecting rod are transmitted. Another connection is not provided at the first interface. The second interface is a mechanical and a hydraulic interface. At this interface, where the cylinder bore and thus the cylinder-piston unit is connected to the second connecting rod, thus all occurring during operation of the engine to the connecting rod forces, in particular the tensile forces of the cylinder-piston unit to the second Transfer connecting rod. The mechanical connection to the second interface can again be non-positively, positively or materially. Further, a hydraulic connection between the engine oil circuit and the cylinder-piston unit is formed at this interface, so that the cylinder-piston unit is supplied with engine oil.
    It may further be provided that a lower stop for the adjusting piston is formed on the second connecting rod part. The lower stop is therefore very robust and can be easily manufactured.
    A simple embodiment is possible if the cylinder bore is formed with the upper stop in a cylinder housing.
    In a further variant it can be provided that the cylinder housing consists of a different material than the other connecting rod parts. The cylinder housing with the cylinder bore, in which the highest loads occur, can therefore be made of a correspondingly high-quality material. For the other components, in particular the first and the second connecting rod, which are subject to lower loads, a cheaper material can be selected or a material that is easier to work.
    Advantageously, it may further be provided that the cylinder bore and / or the adjusting piston is / are coated. This also allows the desired strength and the desired sliding properties between the cylinder bore and adjusting piston can be generated.
    In yet another variant can be provided that the cylinder bore and / or the adjusting is heat treated / are. This also makes it possible to set the desired strength properties of the cylinder bore or of the adjusting piston.
    A very stable connecting rod can be obtained if the cylinder housing has an elongate cross section, preferably an elliptical cross section. The cross section is a section through the connecting rod perpendicular to the longitudinal direction of the connecting rod and thus perpendicular to the longitudinal axis of the adjusting piston or the cylinder bore of the cylinder-piston unit. The cylinder bore of the cylinder-piston unit is circular in cross section and has the advantages associated therewith, such as simple production and good guidance of the adjusting piston in the cylinder bore, etc. Due to the elongated cross section of the cylinder housing, preferably an elliptical cross section, wherein the main axis of the ellipse is perpendicular to the width of the connecting rod, the specified by the crankshaft width of the connecting rod is maintained. Perpendicular to the width, the connecting rod may have larger dimensions. This creates accumulations of material that increase stability and provide space for oil drilling, etc.
    Furthermore, the invention also relates to a method for mounting the length-adjustable connecting rod described above. It is a method should be provided that allows easy production of a length-adjustable connecting rod with tight tolerances and good leadership. For this purpose, it is provided according to the invention that the method for mounting comprises the following steps: provision of at least one piston rod seal and / or at least one piston rod scraper in the region of the piston rod and at least one piston seal in the region of the adjusting piston;
    Inserting the adjusting piston with the piston rod into the cylinder bore; - connecting the piston rod to the first connecting rod part at the first interface; - Connecting the cylinder bore with the second connecting rod part at the second interface.
    As seals can gap seals or touching seals such. B. plastic rings are provided. With touching seals the scraper can be omitted. A scraper is preferably assigned to the cylinder housing, the seals on the piston rod may be designed rod side as a piston seal or cylinder housing side as a rod seal.
    The fact that the piston rod and the piston and the cylinder bore and the rod guide are made coaxially, close tolerances and good guidance of the adjusting piston in the cylinder bore are possible. The joints between the cylinder-piston unit and the first and the second connecting rod part are easily accessible from the outside, so that an easy assembly and control of the connections is possible.
    The method may include a further step of attaching an anti-rotation device to the cylinder-piston unit. The rotation can be mounted between the adjusting piston and the cylinder bore or between the piston rod and the cylinder housing. This ensures that the adjusting piston always runs in the correct position in the cylinder bore.
    In a further variant, it can be provided that a functional test of the cylinder-piston unit is carried out. The functional test may be carried out before connecting the cylinder-piston unit to the two connecting rods or after connecting the cylinder-piston unit to the first of the two connecting rods, i. H. depending on the order of assembly after connecting to the first and second connecting rod and before connecting to the second or first connecting rod. Any existing errors can still be easily remedied at this time.
    Furthermore, it can be provided that connecting the piston rod to the first connecting rod part and connecting the cylinder bore to the second connecting rod part by means of screwing, pressing, shrinking by means of temperature difference, gluing, welding or soldering. As a result, a good and simple production and a secure connection between the respective parts are possible.
    The invention further relates to the use of the above-described length-adjustable connecting rod in an internal combustion engine with at least one reciprocating piston. This provides an internal combustion engine with an adjustable compression ratio that is very easy to manufacture and control, to provide tight tolerances in the cylinder
    Piston unit allows and allows a good guidance of the adjusting piston in the cylinder bore, so that the wear can be reduced.
    In a further aspect, the invention also relates to an internal combustion engine having at least one reciprocating piston and having at least one adjustable compression ratio in a cylinder and a length-adjustable connecting rod connected to the reciprocating piston according to the embodiments described above. Preferably, all the reciprocating piston of an internal combustion engine are equipped with such a length-adjustable connecting rod, but this is not required. The fuel economy of such an internal combustion engine can be considerable and up to 20% if, depending on the respective operating state, the compression ratio is adjusted accordingly.
    According to a development of the internal combustion engine, a control drive can be provided with at least one timing chain, a tensioning and / or guide rail, and / or a chain tensioner which connects the crankshaft to the at least one camshaft of the internal combustion engine. The timing drive is important because it can have a significant influence on the dynamic load of the engine and thus also on the length-adjustable connecting rod. This is preferably designed so that no excessive dynamic forces are introduced via the control drive. Alternatively, such a timing drive can also be formed with a spur gear toothing or with a drive belt, for example a toothed belt, which is pretensioned by means of a tensioning device with tensioning roller.
    In the following the invention will be explained in more detail with reference to drawings. Show it:
    FIG. 1 shows a schematic cross section through an internal combustion engine,
    2 shows a connecting rod of FIG. 1 with a cylinder-piston unit for Längenverstel ment of the connecting rod,
    FIG. 3 shows a switching arrangement in a first switching position for that shown in FIG
    Connecting rod, and
    Figure 4: the switching arrangement of Fig. 3 in a second switching position for the connecting rod shown in Fig. 2.
    In Fig. 1, a combustion engine (gasoline engine) 1 is shown in a schematic representation. The internal combustion engine 1 has three cylinders 2.1, 2.2 and 2.3, in each of which a reciprocating piston 3.1, 3.2, 3.3 moves up and down. Furthermore, the internal combustion engine 1 comprises a crankshaft 4, which is rotatably supported by means of crankshaft bearings 5.1, 5.2, 5.3, 5.4. The crankshaft 4 is by means of
    Connecting rods 6.1, 6.2 and 6.3 respectively associated with associated reciprocating 3.1, 3.2 and 3.3. For each connecting rod 6.1, 6.2 and 6.3, the crankshaft 4 has an eccentrically arranged crankshaft journals 7.1, 7.2 and 7.3. The large connecting rod 8.1, 8.2, and 8.3 is each mounted on the associated crankshaft journal 7.1, 7.2 and 7.3. The small connecting rod 9.1, 9.2 and 9.3 is respectively mounted on a piston pin 10.1, 10.2 and 10.3 and so pivotally connected to the associated reciprocating 3.1.3.2 and 3.3.
    The crankshaft 4 is provided with a crankshaft sprocket 11 and coupled to a camshaft sprocket 13 by means of a timing chain 12. The camshaft sprocket 13 drives a camshaft 14 with its associated cams for actuating the intake and exhaust valves (not shown in detail) of each cylinder 2.1, 2.2 and 2.3. The slack side of the timing chain 12 is tensioned by means of a pivotally mounted clamping rail 15 which is pressed by means of a chain tensioner 16 to this. The Zugtrum the timing chain 12 can slide along a guide rail. The essential operation of this control drive including the fuel injection and ignition by spark plug is not explained in detail and assumed to be known.
    The eccentricity of the crankshaft journals 7.1, 7.2 and 7.3 are mainly the stroke Hk, especially if, as in the present case, the crankshaft 4 is arranged exactly centered under the cylinders 2.1, 2.2 and 2.3. In Fig. 1, the reciprocating piston 3.1 is shown in its lowermost position, while the reciprocating piston 3.2 is shown in its uppermost position. The difference results in the present case, the stroke HK. The remaining height Hc (see cylinder 2.2) gives the remaining compression height in cylinder 2.2. In conjunction with the diameter of the reciprocating piston 3.1.3.2 or 3.3 or the associated cylinder 2.1.2.2 and 2.3 results from the stroke Hk the stroke volume Vh and from the remaining compression height Hc is calculated, the compression volume Vc. Of course, the compression volume Vc significantly depends on the design of the cylinder cover. From these volumes Vh and Vc, the compression ratio ε is calculated. ε is calculated from the sum of the stroke volume Vh and the compression volume Vc divided by the compression volume Vc. Today's values for gasoline engines are between 10 and 14.
    Thus, depending on the operating point (speed n, temperature T, throttle position) of the internal combustion engine 1, the compression ratio ε can be adjusted, the connecting rods 6.1, 6.2 and 6.3 according to the invention designed adjustable in their length. As a result, e.g. be operated in the partial load range with a higher compression ratio than in the full load range.
    2, by way of example, the connecting rod 6.1 is shown, which is, however, configured identically to the connecting rods 6.2 and 6.3. The following description applies accordingly to all connecting rods. The connecting rod 6.1 has a first connecting rod part 17.1 and a second connecting rod part 19.1. In the first connecting rod part 17.1, the said small connecting rod 9.1 is formed. The second connecting rod part 19.1, together with a lower bearing shell 20.1, surrounds the said large connecting rod eye 8.1. The lower bearing shell 20.1 and the second Pleuelteil 19.1 are connected to each other in the usual way by means of fastening means. Between the first Pleuelteil 17.1 and the second Pleuelteil 19.1 a cylinder-piston unit 18.1 is arranged. The cylinder-piston unit 18.1 comprises an adjusting piston 21.1 which is fixedly connected to a piston rod 22.1. The adjusting piston 21.1 and the piston rod 22.1 are thus integrally formed, d. H. they form a component. The adjusting piston 21.1 is guided in a cylinder bore 55.1 formed in a cylinder housing 23.1. The adjusting piston 21.1 is designed as a stepped piston. Below the adjusting piston 21.1, a first pressure chamber 24.1 with a circular cross section is formed by the adjusting piston 21.1 and the cylinder bore 23.1. Above the adjusting piston 21.1, a second pressure chamber 25.1 with an annular cross-section is formed by the adjusting piston 21.1 and the cylinder bore 23.1. The cylinder-piston unit 18.1 with the adjusting piston 21.1 and the cylinder bore 23.1 is part of an adjusting mechanism for changing the length of the connecting rod 6.1. The adjusting mechanism also includes a hydraulic circuit described in greater detail below, which ensures an inflow or outflow of the hydraulic fluid into and out of the pressure chambers 24.1 and 25.1 and thus permits or locks a movement of the adjusting piston 21.1.
    The cylinder housing 55.1 has at its upper end, that is to say at the end associated with the first connecting rod part 17.1, an upper stop 50.1 for the adjusting piston 21.1. The upper stop 50.1 is thus formed integrally with the cylinder bore 23.1 in the cylinder housing 55.1, so that these two parts in the same component, the cylinder housing 55.1, are formed. As a result, the upper stop 50.1 is very robust. The upper stop 50.1 is part of the second pressure chamber 25.1. Through the upper stop 50.1 performs a rod guide 51.1 through, through which the piston rod 22.1 is guided out of the cylinder bore 23.1 to the outside. If the connecting rod 6.1 is in its long position, then the adjusting piston 21.1 bears against the upper stop 50.1 with a second adjusting piston side 28.1. At the second connecting rod part 19.1, a lower stop 52.1 is formed for the adjusting piston 21.1. If the connecting rod 6.1 is in its short position, then the adjusting piston 21.1 bears against the lower stop 52.1 with a first adjusting piston side 27.1. The lower stop 52.1 is part of the first pressure chamber 24.1.
    The cylinder-piston unit 18.1 further comprises a first interface 53.1 and a second interface 54.1. The first interface 53.1 is formed between the end of the piston rod 22.1, which protrudes from the cylinder housing 55.1, and the first connecting rod part 17.1. About this first interface 53.1, the piston rod 22.1 is connected to the first connecting rod part 17.1. This first interface 53.1 is a purely mechanical interface. The piston rod 22.1 and the first connecting rod part 17.1 are connected to one another at the first interface 53.1 in a force-locking, positive-locking or material-locking manner in such a way that the forces occurring during operation of the internal combustion engine 1 on the connecting rod 6.1, i. the tensile and compressive forces are transmitted from one of the two components to the other of the two components. The second interface 54.1 of the cylinder-piston unit 18.1 is formed between the end of the cylinder bore 23.1, or of the cylinder housing 55.1, which faces the second connecting rod part 19.1 and the second connecting rod part 19.1. Via this second interface 54.1, the cylinder bore 23.1 is connected to the second connecting rod part 19.1. The second interface 54.1 is a mechanical and hydraulic interface. In other words, at the second interface 54.1, the forces occurring in the operation of the internal combustion engine 1 on the connecting rod 6.1, in particular the tensile forces, are transferred from the cylinder housing 55.1 to the cylinder bore 23.1 and the adjusting piston 21.1 arranged therein to the second connecting rod part 19.1 and vice versa. The connection between the cylinder housing with the cylinder bore 23. 1 and the second connecting rod part 19. 1 at the second interface 54. 1 can likewise be effected in a force-fitting, positive-fit or material-locking manner. In addition, a hydraulic connection between the second connecting rod part 19.1 and the cylinder bore 23.1 is formed at the second interface 54.1, so that the cylinder-piston unit 18.1 is supplied with engine oil from the engine oil circuit. The connection between the first connecting rod part 17.1 and the piston rod 22.1 and the connection between the cylinder bore 23.1 and the second connecting rod part 19.1 can be produced, for example, by screwing in, pressing in, shrinking by means of temperature difference, gluing, welding or soldering. Due to the fact that the connection between the first connecting rod part 17.1 and the piston rod 22.1 and the connection between the second connecting rod part 19.1 and the cylinder bore 23.1 are easily accessible from the outside, these connections can be easily manufactured and well controlled.
    In order to ensure a good stability of the highly loaded cylinder bore 23.1, the cylinder housing 55.1 is preferably made of a different material than the other connecting rod parts, i. the first Pleuelteil 17.1, the second Pleuelteil 19.1, the adjusting piston 21.1 and the piston rod 22.1. Preferably, the cylinder housing 55.1 is therefore made of a solid material. The cylinder bore 23.1 and / or the adjusting piston 21.1 may / may also have a coating or be heat treated. The cylinder bore 23.1 and the adjusting piston 21.1 are in
    Cross section perpendicular to its longitudinal axis preferably circular. The cylinder housing 55.1 preferably has a different cross section, for example, an elongated cross section, whose longitudinal axis is arranged transversely to the width of the connecting rod. Preferably, the cross section of the cylinder housing 55.1 is elliptical, wherein the main axis of the ellipse extends transversely to the width of the connecting rod. As a result, the width of the connecting rod 6.1, which is predetermined by the structural conditions of the crankshaft, can be maintained. Nevertheless, it is possible to design the connecting rod across its width longer. The connecting rod 6.1 thus has accumulations of material that provide better stability and in which, for example, the required oil passages can be arranged.
    During assembly of the length-adjustable connecting rod 6.1, the procedure is as follows: First, at least one rod seal and at least one piston rod scraper are mounted in the area of the rod guide 51.1 in the cylinder housing 55.1 or on the piston rod 22.1. The scraper is preferably assigned to the cylinder housing 55.1. Subsequently, the piston seal is fastened on the adjusting piston 21.1 or on the cylinder housing 55.1. In principle, gap seals are also possible. If the seals and the piston rod scraper are mounted, the piston rod 22.1 is inserted with the adjusting piston 21.1 into the cylinder bore 23.1 of the cylinder-piston unit 18.1. Subsequently, the piston rod 22.1 at the first interface 53.1 with the first connecting rod 17.1, i. with the small connecting eye 9.1, connected. This connection is made for example by screwing, pressing, shrinking by means of temperature difference, gluing, welding or soldering. Following this, an anti-twist device, for example a pin, is mounted between the adjusting piston 21.1 and the cylinder bore 23.1 or between the piston rod 22.1 and the cylinder housing 55.1. The preassembled cylinder-piston unit 18.1 fastened to the first connecting rod part 17.1 is then subjected to a functional test before it is connected to the second connecting rod part 19.1 at the second interface 54.1. This connection is preferably carried out by screwing, pressing, shrinking by means of temperature difference, gluing, welding or soldering. The connection of the cylinder-piston unit 18.1 with the two connecting rods 17.1, 19.1 can also be done in reverse order. The functional test can also be done entirely before connecting and reverse connection order before connecting the cylinder-piston unit 18.1 with the first connecting rod 17.1.
    In the following, the hydraulic circuit 26.1 used in the connecting rod 6.1 will now be explained in more detail with reference to FIGS. 3 and 4. The adjusting piston 21.1 is designed as a stepped piston. Under a stepped piston is generally understood to mean a two-sided piston with different sized effective surfaces. A first associated with the first pressure chamber 24.1
    Adjusting piston side 27.1 is configured circular. A the second pressure chamber 25.1 associated second Verstellkolbenseite 28.1 is designed annular. The hydraulic circuit 26.1 is operated with engine oil. For this purpose, an oil supply channel 29.1 communicates with the large connecting rod eye 8.1 in connection, whereby the hydraulic circuit 26.1 engine oil can be supplied or possibly flows out of this. Following the oil supply channel 29.1 is a Rückströmdrossel 30.1 provided with a check valve 30a.1 and a throttle 30b.1 connected in parallel thereto. Following the Rückströmdrossel 30.1 the engine oil passes through the channel 31.1 to a control valve 32.1. The control valve 32.1 comprises an actuating piston 33.1, which is displaceably guided in a receiving bore 34.1 against a compression spring 35.1. The actuating piston 33.1 has a first stop side 36.1 and a second stop side 37.1, which can come into abutment with corresponding stops 38.1 and 39.1. If the pressure in the channel 31.1 is not sufficient to displace the actuating piston 33.1 against the compression spring 35.1, the actuating piston 33.1 assumes the position shown in FIG. 3 and lies with its first stop side 36.1 against the first stop 38.1.
    From the first pressure chamber 24.1 leads a return channel 40.1 to the control valve 32.1. An oil passage 42.1, which can be blocked by a check valve 41.1, likewise communicates with the control valve 32.1 and leads to the first pressure chamber 24.1. The first return passage 40.1 is closed in the position of the actuating piston 33.1 shown in FIG. Oil from the first pressure chamber 24.1 can not escape due to the closed check valve 41.1. The adjusting piston 21.1 moves through the gas and mass forces occurring in the upper position and is then hydraulically locked. As a result, the connecting rod 6.1 is in its extended, extended position. In this position, the first adjusting piston 27.1 of the adjusting piston abuts against the upper stop 50.1. From the second pressure chamber 25.1 leads a return line 43.1 to the control valve 32.1. In the position shown in FIG. 3, engine oil can flow out of the second pressure chamber 25.1 via the return line 43.1 and the control valve 32.1 into the crankcase via the outlet 44.1. In the outgoing from the second pressure chamber 25.1 to the control valve 32.1 oil passage 45.1 a check valve 46.1 is arranged. The arrows in FIG. 3 symbolize the oil flow direction or the direction of movement. However, the pressure applied to the control valve 32.1 is not sufficient to remove the blocking of the adjusting piston 21.1.
    However, if now the pressure on the oil pump of the engine increases, there is a displacement of the actuating piston 33.1 against the force of the compression spring 35.1 (see Fig. 4). As a result, the first return passage 40.1 is opened and the engine oil can flow out of the first pressure chamber 24.1 and via the channel 31.1 and the return flow throttle 30.1 when the adjusting piston 21.1 moves downwards due to the gas and mass forces occurring. At the same time, the return line 43.1 is closed and filled via the oil passage 45.1 and the check valve 46.1 of the second pressure chamber 25.1 with engine oil. As soon as the adjusting piston 21.1 bears against the lower stop 52.1, the adjusting piston 21.1 is hydraulically locked in this position, as long as a sufficient pressure is applied to the control valve 32.1. In the lowest position of the adjusting piston 21.1, the connecting rod 6.1 assumes its short position. This position is advantageous at full load, whereas the position shown in FIG. 3 for the partial and low load operation is premature.
    With regard to the further mode of action and operation, reference is additionally made to WO 2015/055582 A2, which describes the same circuit and variants thereof, which may also be used.
    List of Reference Symbols I. Internal combustion engine 2.1.2.2.2.3 Cylinder 3.1.3.2.3.3 Reciprocating piston 4 Crankshaft 5.1.5.2.5.3.5.4 Crankshaft bearing 6.1.6.2.6.3 Connecting rod 7.1.7.2.7.3 Crankshaft journal 8.1.8.2.8.3 Large connecting rod 9.1.9.2.9.3 Small connecting rod 10.1.10.2.10.3 piston pin II crankshaft sprocket 12 timing chain 13 camshaft 14 cam shaft 15 clamping rail 16 chain tensioner 17.1 first connecting rod 18.1 cylinder-piston unit 19.1 the second connecting rod 20.1 bearing shell 21.1 adjustment piston 22.1 piston rod 23.1 bore 24.1 first pressure chamber 25.1 second pressure chamber 26.1 hydraulic circuit 27.1 first Adjusting piston side 28.1 second adjusting piston side 29.1 oil supply channel 30.1 return flow restrictor 30a.1 check valve 30b.1 throttle 31.1 channel 32.1 control valve 33.1 actuating piston 34.1 receiving bore 35.1 compression spring 36.1 first stop side 37.1 second stop side 38.1 first stop 39.1 second stop 40.1 return passage 41.1 check valve 42.1 oil passage 43 .1 Return line 44.1 Outlet 45.1 Oil channel 46.1 Check valve 50.1 Upper stop 51.1 Bar guide 52.1 Lower stop 53.1 First interface 54.1 Second interface 55.1 Cylinder housing
    Vh stroke volume
    Vc Compression volume HC Compression height HK Stroke ε Compression ratio n Speed T Temperature
    权利要求:
    Claims (14)
    [1]
    1. Length-adjustable connecting rod (6.1, 6.2, 6.3) for an internal combustion engine (1), in particular a gasoline engine, with a first connecting rod part (17.1) and a second connecting rod part (19.1), wherein the first connecting rod part (17.1) relative to the second connecting rod part (19.1 ), and with at least one cylinder-piston unit (18.1) to adjust the first connecting rod part (17.1) relative to the second connecting rod part (19.1), the cylinder-piston unit (18.1) comprises a cylinder bore (23.1) , an adjusting piston (21.1) arranged long in the cylinder bore (23.1), a piston rod (22.1) and at least one first pressure chamber (24.1) provided in the cylinder bore (23.1) for receiving engine oil which is unilaterally displaceable by the movable adjusting piston (21.1) is limited, characterized in that the cylinder-piston unit (18.1) comprises a first and a second interface (53.1, 54.1), the piston rod (22.1) is formed integrally with the adjusting piston (21.1), and via the first interface (53.1) of the Zyliner piston unit (18.1) is connected to the first connecting rod part (17.1), the cylinder bore (23.1) has an integral upper stop (50.1) for the adjusting piston (21.1), and Cylinder bore (23.1) via the second interface (54.1) of the cylinder-piston unit (18.1) with the second connecting rod part (19.1) is connected and wherein the first interface (53.1) of the cylinder-piston unit (18.1) a purely mechanical interface is and the second interface (54.1) of the cylinder-piston unit (18.1) is a mechanical and a hydraulic interface.
    [2]
    2. Length-adjustable connecting rod (6.1,6.2, 6.3) according to claim 1, characterized in that on the second connecting rod part (19.1), a lower stop (52.1) for the adjusting piston (21.1) is formed.
    [3]
    3. Length-adjustable connecting rod (6.1, 6.2, 6.3) according to claim 1 or 2, characterized in that the cylinder bore (23.1) with the upper stop (50.1) in a cylinder housing (55.1) is formed.
    [4]
    4. Length-adjustable connecting rod (6.1, 6.2, 6.3) according to one of claims 1 to 3, characterized in that the cylinder housing (55.1) consists of a different material than the other connecting rod parts.
    [5]
    5. Length-adjustable connecting rod (6.1, 6.2, 6.3) according to one of claims 1 to 4, characterized in that the cylinder bore (23.1) and / or the adjusting piston (21.1) is / are coated.
    [6]
    6. Length-adjustable connecting rod (6.1, 6.2, 6.3) according to one of claims 1 to 5, characterized in that the cylinder bore (23.1) and / or the adjusting piston (21.1) is heat treated / are.
    [7]
    7. Length-adjustable connecting rod (6.1, 6.2, 6.3) according to one of claims 1 to 6, characterized in that the cylinder housing (55.1) has an elongated cross section, preferably an elliptical cross section.
    [8]
    8. A method for assembling a length-adjustable connecting rod (6.1,6.2, 6.3) according to one of claims 1 to 7, characterized by the following steps: - Provision of at least one piston rod seal and / or at least one Kolbenstangenabstreifers in the region of the piston rod (22.1) and at least one Piston seal in the area of the adjusting piston (21.1); - Inserting the adjusting piston (21.1) with the piston rod (22.1) in the cylinder bore (23.1); - connecting the piston rod (22.1) to the first connecting rod part (17.1) at the first interface (53.1); - Connecting the cylinder bore (23.1) with the second connecting rod part (19.1) at the second interface (54.1).
    [9]
    9. The method according to claim 8, characterized in that on the cylinder-piston unit (18.1) an anti-rotation device is mounted.
    [10]
    10. The method according to any one of claims 8 or 9, characterized in that a functional test of the cylinder-piston unit (18.1) is performed.
    [11]
    11. The method according to any one of claims 8 to 10, characterized in that the connecting the piston rod (22.1) with the first connecting rod part (17.1) and connecting the cylinder bore (23.1) with the second connecting rod part (19.1) by means of screwing, pressing, shrinking by means of temperature difference, gluing, welding or soldering.
    [12]
    12. Use of a length-adjustable connecting rod (6.1, 6.2, 6.3) according to one of claims 1 to 7 in an internal combustion engine (1) with at least one reciprocating piston (3.1, 3.2, 3.3).
    [13]
    13. internal combustion engine (1) with at least one reciprocating piston (3.1, 3.2, 3.3) and with at least one adjustable compression ratio in a cylinder (2.1,2.2, 2.3) and a piston connected to the reciprocating piston (3.1,3.2, 3.3) connecting rod (6.1, 6.2, 6.3) according to one of claims 1 to 7.
    [14]
    14. Internal combustion engine according to claim 13, characterized in that a control drive with at least one timing chain (12), a clamping and / or guide rail (15) and / or a chain tensioner (16) is provided or are the crankshaft (4) with at least one camshaft (14) connects.
    类似技术:
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    同族专利:
    公开号 | 公开日
    DE102016120948A1|2018-05-03|
    AT519292B1|2019-07-15|
    AT519292A3|2018-09-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    AT519947A3|2017-05-12|2019-02-15|Avl List Gmbh|Length adjustable connecting rod with two telescopic connecting rod sections|US1610137A|1926-01-28|1926-12-07|Charles E Kratsch|Connecting rod|
    US2217721A|1938-09-14|1940-10-15|Mary Adeline Reynolds|Internal combustion engine|
    DE19925268B4|1999-06-01|2011-07-21|FEV Motorentechnik GmbH, 52078|Chain tensioner for a reciprocating internal combustion engine with variable combustion chamber|
    DE10255299A1|2002-11-27|2004-06-17|Fev Motorentechnik Gmbh|Connecting rod for use on a reciprocating engine with variable adjustable compression ratio|
    DE102005055199B4|2005-11-19|2019-01-31|FEV Europe GmbH|Reciprocating internal combustion engine with adjustable variable compression ratio|
    AT511803B1|2011-12-23|2013-03-15|Avl List Gmbh|CONNECTING ROD FOR A PUSH-PISTON MACHINE|
    AT514071B1|2013-10-18|2014-10-15|Avl List Gmbh|Length adjustable connecting rod|
    CN104963935A|2015-05-05|2015-10-07|苏犁|Cylinder type internal combustion engine retractable connecting rod|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    DE102016120948.1A|DE102016120948A1|2016-11-03|2016-11-03|Connecting rod with adjustment mechanism between connecting rod and connecting rod|
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