KR101468261B1 - Apparatus for variably adjusting the control times of gas exchange valves in an internal combustion engine - Google Patents

Abstract

An apparatus for variably adjusting control times of gas exchange valves in an internal combustion engine. The apparatus has a driving element, an output element, at least one pressure chamber, a pressurized medium supply device, and at least one pressure accumulator. The supply device allows pressurized medium to be fed to or discharged from the pressure chamber. A phase angle of the output element relative to the input element can be changed by feeding or discharging pressurized medium to or from the pressure chamber. The pressure accumulator encompasses a movable element that has a first pressure surface which partially delimits a storage space. The storage space is or can be connected to the supply device. An energy store applies a force to the movable element in the direction of an initial position. The movable element can be moved against the force of the energy store by pressurizing the storage space.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an apparatus for adjusting the control time of a gas exchange valve of an internal combustion engine,

The present invention relates to an apparatus for varying the control time of gas exchange valves of an internal combustion engine, comprising a drive member, an output member, at least one pressure chamber, a pressure medium supply device and at least one pressure accumulator , The pressure medium can be supplied to the at least one pressure chamber or the pressure medium can be discharged from the pressure chamber by the pressure medium supply device and the pressure medium is supplied to the pressure chamber or the pressure medium is discharged from the pressure chamber, The phase position of the output member may be variable and the pressure accumulator includes a displaceable member having a first pressure surface that partially limits the storage space wherein the storage space may be connected to or connected to the pressure medium supply, The energy accumulator is a spring that biases the displaceable member in the direction of the starting position In this case, the displaceable member can be displaced against the force of the energy accumulator by supplying pressure to the storage space.

In modern internal combustion engines, in order to be able to variably configure the phase relationship between the crankshaft and the camshaft in a prescribed angular range, that is, between a maximal advance position and a maximal retard position, An apparatus for variably adjusting the control time of the exchange valves is used. Such an apparatus typically includes an actuating device that is driven by the crankshaft and transmits the torque of the crankshaft to the camshaft. Inside the actuating device, a hydraulic actuator is formed which allows the phase position between the crankshaft and the camshaft to be influenced as desired. A pressure medium supply device is provided for supplying pressure medium to the actuating device.

A device of the type mentioned above is known, for example, from EP 1 025 343 B1. The apparatus includes two rotatable rotors, one of which is connected to the crankshaft and driven, and the inner rotor is connected to the camshaft in a non-rotatable manner. The apparatus includes a plurality of hollow spaces, each of which is divided by vanes into two pressure chambers that interact. The vanes are displaced within the pressure chambers by feeding the pressure medium to the pressure chambers or by discharging the pressure medium from the pressure medium so that the mutual rotation of the rotors and thus the rotation of the camshaft relative to the crankshaft is as desired .

Feeding the pressure medium to the pressure chambers or discharging the pressure medium from the pressure chambers is controlled by a pressure medium supply device including a pressure medium pump, a tank, a control valve, and a plurality of pressure medium lines. In this connection, the pressure medium line connects the pressure medium pump to the control valve. Each additional pressure media line connects one of the working ports of the control valve to the pressure chambers. The pressure medium is typically supplied from a lubricating oil circuit of an internal combustion engine.

In order to ensure the functioning of the device, the pressure in the pressure medium system must exceed a certain value at each operating phase of the internal combustion engine. This is important in the idling phase of the internal combustion engine, especially since the pressure medium pump is driven by the crankshaft and thereby the system pressure rises with the speed of the internal combustion engine. In addition, the system pressure supplied by the pressure medium pump depends on the pressure medium temperature, i.e., as the temperature rises, the system pressure drops. Thus, the pressure medium pump must be configured in such a way that the pressure medium pump can sufficiently provide the system pressure under worst-case conditions so that the phase position of the inner rotor relative to the outer rotor can be adjusted quickly enough. The pressure medium pump must be configured accordingly to be able to ensure the required adjustment speed in the worst pressure conditions, such as high pressure medium temperature and / or low rotation speed. As a result, a pressure medium pump is used, which is configured to meet the maximum requirements of the operating device, so that the size of the most operating steps of the internal combustion engine is set too large. In accordance with this alternative embodiment, an adjustable pressure medium pump providing a pressure medium may be used if desired. The increased complexity in these two cases negatively affects the cost of the internal combustion engine, the space requirement and fuel consumption.

Such a device is also known in another form in US 5,775,279 A. According to an embodiment of the publication, a pressure accumulator connected to the pressure medium supply device is disposed between the pressure medium pump and the control valve. These pressure accumulators are filled with the pressure medium at high system pressure stages. If the system pressure drops, the pressure accumulator is automatically emptied, thereby providing additional pressure medium in the pressure medium supply. The phase adjustment of the device is thereby supported. A disadvantage of such an embodiment is that the system pressure does not drop on the basis of the adjusting process, but on the basis of another external situation, for example, when the pressure accumulator is emptied when it is lowered by deceleration of the rotational speed. Thereby, lower pressure support and smaller pressure medium volume are provided from the pressure accumulator for subsequent phase adjustment procedures. A further disadvantage is that the maximum pressure at which the pressure accumulator can support the pressure medium supply corresponds to the pressure present in the pressure medium supply just before the phase adjustment process. If the adjustment request is transmitted from the engine control unit to the device under high temperature and low rotational speed conditions, the pressure support of the pressure accumulator is less, since the system pressure that was filled in the pressure accumulator is low. This may cause the adjustment process to fail or the adjustment speed to decrease significantly. Therefore, even in this case, the pressure medium pump must be configured to match the peak load that causes disadvantages.

It is an object of the present invention to provide an apparatus for variably adjusting the control time of gas exchange valves of an internal combustion engine so that safe adjustment of the control time is ensured even under high regulation speed conditions in each operation stage of the internal combustion engine. Another object is to make it possible to exclude that the pressure medium pump is set to an oversized size (configuration conforming to the expected peak load) as well as the use of a variable pressure medium pump is excluded.

This object is achieved according to the present invention by including a displaceable member having a back pressure surface at least partially restricting the back pressure space, wherein the displaceable member is displaceable in the direction of the starting position by being supplied with the pressure medium in the back pressure space have. The displaceable member may be formed, for example, as a pressure piston, which can be displaced in the pressure tank against the force of an energy accumulator formed, for example, as a spring member. When the pressure medium is supplied to the storage space, the volume of the storage space increases the cost for the back pressure space. When the system pressure in the pressure medium supply drops, the force of the energy accumulator exceeds the force caused by the system pressure on the first pressure surface. Whereby the pressure piston is pressurized by the energy accumulator to a starting position where the volume of the storage space is minimal.

Alternatively to the spring member, other types of energy accumulators may be used, such as, for example, a reversibly deformable body of elastomeric material, or gas pocket filled with gas. When the pressure accumulator is supplied with the pressure medium in the back pressure space during the operation stage of the internal combustion engine in which the pressure accumulator is to send the pressure medium to the pressure medium supply device, on the displaceable member, in addition to the force of the energy accumulator, The force of the force acts. This additional force is formed from the pressure in the back pressure chamber acting on the back pressure side. For the value F of the force F = pA _G is applied, where p corresponds to the pressure acting on the back pressure surface and A _G corresponds to the area of the back pressure surface.

By increasing the pressure provided by the pressure accumulator, the pressure accumulator can prevent peak consumption, so that the pressure medium pump can be designed for normal operation of the internal combustion engine. To ensure safe and rapid phase position adjustment, the pressure medium pump may be set to an oversized size or the pump may not need to be adjusted. In addition, the adjustment speed of the operating device increases. Alternatively, if the adjustment speed is the same, the actuating device can be set smaller. Thus, mass, mass moment of inertia and cost can be reduced.

In an improvement of the present invention, the displaceable member includes at least one second pressure surface that partially limits the control space, and the displaceable member can be displaced against the force of the energy accumulator by being supplied with pressure in the control space , The pressure medium flow from the storage space to the control space in the pressure accumulator is blocked. Moreover, the storage space and the control space may not be interconnected within the pressure accumulator. Preferably, the displaceable member is displaced in the same direction as when the pressure medium is supplied to the control space by supplying the pressure medium to the storage space, preferably in a direction away from the starting position of the displaceable member.

By forming a pressure accumulator comprising a displaceable member that partially limits pressure spaces isolated from one another in the pressure accumulator, the two pressure spaces can be controlled separately from one another, i.e., filled and / or Can be emptied. Except for leakage, there is no connection between pressure spaces. Thus, for example, various pressure sources can be used for filling the storage space and the control space. According to an alternative embodiment, a pressure medium connection may be provided inside the pressure accumulator between the storage space and the control space. The pressure medium supplied to the control space can reach the storage space through the pressure medium connection portion. In this case, however, the pressure medium flow from the storage space to the control space must be prevented. This can be realized, for example, via a pressure medium channel provided within the pressure tank of the pressure accumulator or inside the pressure piston and within which a check valve is located. In this case, filling of the storage space and the control space can be done only by filling the control space. And if the pressure accumulator should be emptied, the control space is connected to the tank. The storage space is emptied into the pressure medium supply device, and the control space is emptied into the tank to be pressurized. Overflow of the pressure medium, which can consist of storage space and control space, is prevented by the check valve. When the displaceable member is displaced in the same direction as when the pressure medium is supplied to the control space by supplying the pressure medium to the storage space, the control space can support the filling of the storage space. To this end, the control space is also filled with the pressure medium during the filling of the storage space. This causes one force on the two pressure surfaces of the pressure piston to act on the two pressure surfaces, whereby a greater force is stored in the energy accumulator (the spring member is compressed more strongly). If the filled pressure accumulator is commanded from the engine control unit to support the phase adjustment process, the control space may be emptied regardless of the storage space. In other words, while the storage space is emptied into the pressure medium supply, the control space can be vented into the tank against atmospheric pressure so as to support the phase adjustment process. With a suitable configuration, the air discharge of the control space can be made faster than the storage space being emptied into the pressure medium supply. So that all of the force stored in the energy accumulator acts on the storage space through the first pressure side. As a result, the pressure may rise up to a factor of at most the following equation depending on the load acting on the energy accumulator at this point in the start of the support process.

)만큼 상승한다.In the above equation, A ₁ corresponds to the area of the first pressure surface, and A ₂ corresponds to the area of the second pressure surface. If, for example, a spring member is used as an energy accumulator, the pressure will be at the beginning of the support process, as long as the spring has not yet reached its maximum compression state,

).

In an improvement of the present invention, the back pressure space may be selectively connected to a pressure source or to a tank. A control means may be provided, in which case the back pressure space may be selectively connected to the tank or to the pressure source by the control means. The back pressure space may be connected to the pressure medium pump of the internal combustion engine. The back pressure space may be connected to the tank of the internal combustion engine.

The pressure source may be, for example, a pressure medium supply device or a pressure medium pump of the pressure medium supply device, or may be a pressure source of an independent pressure source, such as a servo consuming device (e.g., a power steering system). At this time, in the case of the pressure of the servo consuming device, the pressure accumulator can be completely filled even in the operating stage which shows a low system pressure. The selective connection with the pressure source or tank is made via control means, for example via a 3/2-way control valve in the form of a switching valve (eg seat valve) or a proportional valve (eg slide valve). According to an alternative embodiment, two control means are considered, one of the control means blocks or opens the connection portion from the pressure source to the back pressure space, and the other control means blocks the connection portion from the back pressure space to the tank Or open. The control means may be, for example, an electromagnetic actuating hydraulic valve, such as a directional control valve (e.g., a switching or proportional valve), or a check valve that may be released, or the like. Such control means receive control signals from the engine control unit of the internal combustion engine and, depending on the control signals, whether the backpressure space is filled or emptied, that is, whether the pressure accumulator should be filled or the venting process should be supported . Likewise, the use of the hydraulic operation control means may be considered. In this case, the hydraulic actuating device of the control means may be connected to the pressure medium supply device. So that the control means can be automatically switched to less than the specified value when the pressure in the pressure medium supply drops. The control related complexity is thereby greatly reduced.

If a tank of the internal combustion engine and / or a pressure medium pump is used for filling the backpressure space or for venting air, no additional components are required in addition to the components that already exist in the internal combustion engine. There is also a lower demand for sealing between the pressure medium tank and the pressure piston because mixing of the pressure medium in the storage space and the back pressure space is allowed. As a result, the sealing member acting between the pressure piston and the pressure tank can be omitted.

It can also be shown that a directional control valve comprising a pressure source, a tank and a respective port connected to the back pressure space is provided as the control means. In an improvement of the present invention, additional ports connected to the storage space or control space may be provided.

The pressure support of the pressure accumulator may be activated by simple switching of one or more control means. In this regard, in the operating steps of the internal combustion engine in which the phase position is kept constant, the volume of the pressure medium accumulated in the storage space is supplied. The pressure support of the pressure accumulator can be used during each phase adjustment procedure. To this end, the control means (directional control valve and / or check valve which can be released) is moved to the position where the storage space is emptied whenever a phase adjustment is required. The pressure accumulator can be filled in the operating phase between the phase adjustment requests. There is also another possibility to provide the pressure support of the pressure accumulator as needed. If the engine control unit detects that the pressure or volume flow supplied from the pressure medium pump is not sufficient for phase adjustment, the engine control unit allows pressure support through the pressure accumulator. Such a measure prolongs the time that the pressure accumulator can be filled, thereby increasing the performance of the pressure accumulator during pressure support. In accordance with this alternative embodiment, the pressure support of the pressure accumulator can only be used as a "boost" function for the adjustment process of the criticality, which requires, for example, high volumetric flow or high regulation speed. If it is detected in the engine control unit that the adjustment process of the threshold should be induced, the engine control unit activates the pressure support through appropriate adjustment of the control means.

It is likewise conceivable to form the control means as a single member with a control valve which controls the pressure medium flow to the pressure chambers of the actuating device or from the pressure chamber.

Preferably the maximum volume of the storage space corresponds to at least twice the volume required for phase adjustment from the maximum retard position to the maximum advancing position.

The pressure accumulator may, for example, be introduced into the pressure medium line between the pressure medium pump and the control valve. According to an alternative embodiment, the pressure accumulator may be introduced into the pressure medium line connecting one of the working ports of the control valve to one of the pressure chambers of the group, among the pressure medium lines. In addition to such an embodiment, a second pressure accumulator may be provided which is introduced into the pressure medium line connecting the other working port of the control valve to the pressure chambers of the other group.

Additional features of the invention will be set forth in the description that follows, and in the drawings in which embodiments of the invention are shown schematically.
1 is a schematic view showing the internal combustion engine only in a very schematic manner.
2A is a longitudinal sectional view showing the operating device cut away.
2B is a cross-sectional view showing the operating device cut away.
Figure 3 is a diagram of a first embodiment of an apparatus according to the present invention.
4 is a view of a second embodiment of the device according to the invention.
Figure 5 is a view of a third embodiment of the device according to the invention.

Fig. 1 schematically shows an internal combustion engine 1, in which a piston 3 resting on a crankshaft 2 in a cylinder 4 is shown. The crankshaft 2 is connected to the intake camshaft 6 or the exhaust camshaft 7 via respective one of the traction drive devices 5 according to the illustrated embodiment and the first and second devices 10, It is possible to provide relative rotation between the crankshaft 2 and the camshafts 6, 7. The devices 10 include one hydraulic actuating device 10a, b and a pressure medium supply device 37, respectively. The cams 8 of the camshafts 6 and 7 actuate one or more intake gas exchange valves 9a or one or more exhaust gas exchange valves 9b. The apparatus 10 may be mounted on only one camshaft of the camshafts 6 and 7 or only one camshaft 6 and 7 on which the apparatus 10 is mounted may be provided.

3 shows a first embodiment of a device 10 according to the invention with actuating devices 10a, b, a pressure medium supply device 37 and a pressure accumulator 43. In Fig. Figures 2a and 2b show the actuating devices 10a, b in longitudinal and transverse sections, respectively. The actuating device 10a, b includes a drive member formed as an outer rotor 22 and an output member formed as an inner rotor 23. [ The outer rotor 22 includes a housing 22a and two side covers 24 and 25 disposed on the axial side surfaces of the housing 22a. The inner rotor 23 is embodied in the form of an impeller and includes a hub member 26 that is substantially cylindrical in shape and has five vanes 27 in the illustrated embodiment from the outer cylindrical circumferential surface of the hub member Extending radially outward. The vanes 27 are independently formed toward the inner rotor 23 and disposed in the vane groove 28 formed in the hub member 26. The vanes 27 are urged radially outward by the vane springs 27a disposed between the groove bottoms of the vane grooves 28 and the vanes 27, respectively.

The plurality of protrusions 30 extend radially inward starting from the outer circumferential wall 29 of the housing 22a. According to the illustrated embodiment, the protrusions 30 are formed as a single member together with the circumferential wall 29. The outer rotor 22 is supported on the inner rotor rotatably with respect to the inner rotor 23 by such circumferential wall portions located radially inwardly as the circumferential wall portions of the projections 30. [

A chain wheel 21 is disposed on the outer jacket surface of the circumferential wall 29 so that torque can be transmitted from the crankshaft 2 to the outer rotor 22 through a chain drive device have.

Each of the side covers 24 and 25 is respectively disposed on one axial side surface of the axial side surfaces of the housing 22a and is non-rotatably fixed on the axial side surface. To this end, each protrusion 30 is provided with a fixing member 32, for example an axial opening through which the screw passes, for non-rotatably fixing the side covers 24, 25 to the housing 22a.

Inside the actuating device 10a, b, a hollow space 33 is formed between two projections 30 adjacent to each other in the circumferential direction. Each of the hollow spaces 33 is defined by such limiting wall portions 34 that are positioned opposite each other and extend substantially radially as the limiting wall portions 34 of the adjacent protrusions 30 in the circumferential direction, In the axial direction, by the side covers 24, 25, by the hub member 26 radially inwardly, and by the circumferential wall 29 radially outwardly. A vane 27 protrudes into each of the hollow spaces 33 and is formed in such a manner that the vane contacts the circumferential wall 29 as well as the side covers 24 and 25 . So that each vane 27 divides the hollow space 33 into two pressure chambers 35, 36 that interact with each other.

The inner rotor 23 can be rotated with respect to the outer rotor 22 in a specified angular range. The angular range is limited by the vane 27 being brought into contact with the corresponding limiting wall portion 34 (the advancing stop portion 34a) of the hollow spaces 33 in one rotation direction of the inner rotor 23. [ Similarly, in the other rotation direction, the angular range is limited by bringing the vane 27 into contact with the other side restriction wall portions 34 of the hollow spaces 33 serving as the retard stopper 34b.

The phase position of the outer rotor 22 with respect to the inner rotor 23 can be varied by supplying pressure to the pressure chambers 35 and 36 of one group and by reducing pressure in the pressure chambers of the other group. When pressure is applied to both of the pressure chambers 35 and 36 of the two groups, the phase positions of the two rotors 22 and 23 can be kept constant with each other. According to this alternative embodiment, the phase position may not supply the pressure medium to any of the pressure chambers 35, 36 during a certain stage. As the hydraulic pressure medium, lubricating oil of the internal combustion engine 1 is usually used.

The pressure medium supply device 37 shown in Fig. 3 is provided for supplying the pressure medium to the pressure chambers 35, 36 or for discharging the pressure medium from the pressure chambers. The pressure medium supply device 37 includes a pressure source embodied as a pressure medium pump 38, a tank 39, a control valve 40, and a plurality of pressure medium lines 41. The control valve 40 includes a supply port P, a tank port T and two operation ports A and B. [ Each of the pressure medium lines 41 connects the supply port P and the pressure medium pump 38 and connects the first pressure chamber 35 to the first working port A and the second pressure chamber 36 And the second operation port B, and connects the tank 39 and the tank port T. So that the pressure medium can reach the supply port P of the control valve 40 from the pressure medium pump 38 through the pressure medium line 41. In the first position of the control valve 40 the supply port P is connected to the first pressure chamber 35 while the second pressure chamber 36 is connected to the tank 39. None of the pressure chambers 35 and 36 is connected to the tank 39 and the supply port P in the second position of the control valve 40. [ The supply port P is connected to the second pressure chamber 36 in the third position of the control valve 40 while the first pressure chamber 35 is connected to the tank 39. [

During the operation of the internal combustion engine 1, the camshafts 6 and 7 are subjected to an alternating torque caused by the rolling contact of the cams 8 to the cam followers. At this time, the force of the valve spring acts on the camshafts 6, 7 in such a manner that they are braked until the gas exchange valve is completely opened. Subsequently, the camshafts 6 and 7 are accelerated by the force of the valve spring. As a result, a pressure peak is generated inside the actuating device 10a, b, by which the pressure chambers 35, 36 connected to the supply port P are emptied to the pressure medium pump 38 , Which greatly slows down the adjustment speed. In order to prevent this, a check valve 42a is provided in the pressure medium line 41 connecting the control valve 40 and the pressure medium pump 38. [ The check valve 42a prevents backflow of the pressure medium from the pressure chambers 35,36, which may be made through the control valve 40 to the pressure medium pump 38. [ The pressure peak is reserved at the check valve 42a, whereby the point at which the pressure chambers 35, 36 is undesirably emptied is effectively prevented, thereby increasing the stability and the speed of adjustment of the torque transmission.

The adjusting speed of the actuating device 10a, b depends on the pressure medium volume flow provided in the pressure medium pump 38 or the pressure provided by the pump. The pressure provided or the provided pressure medium volume flow itself depends on a number of factors, such as the speed of the internal combustion engine 1 and the pressure medium temperature. In order to ensure the required regulating speed even in the worst case conditions, for example high pressure medium temperature and / or low rotational speed, the pressure medium pump 38 has to be adapted accordingly. So that the pressure medium pump 38, which is configured in accordance with the maximum requirements of the actuating devices 10a, b and thus set to an oversize during the most operating phase of the internal combustion engine 1, is used. Also, according to an alternative embodiment thereto, an adjustable pressure medium pump 38 may be used which provides a pressure medium as required. The increased complexity in these two cases negatively affects the fuel consumption and cost of the internal combustion engine 1.

In order to avoid such disadvantages, a pressure accumulator 43 is provided in the apparatus 10 of the present application. The pressure accumulator 43 comprises a displaceable member which is formed as a pressure piston 45 which can be displaced against the force of the energy accumulator within the pressure tank 44. In the illustrated embodiment, the energy accumulator is embodied as a spring member 46. However, another type of energy accumulator, such as, for example, a suitably formed elastomeric body or a gas pocket filled with gas, is conceivable.

The pressure piston (45) includes two pressure surfaces (47, 48). The first pressure surface 47 limits the storage space 49 with the pressure tank 44 and in this case the first pressure surface 47 limits the storage space 49 in the displacement direction of the pressure piston 45 do. The pressure tank 44 and the pressure piston 45 limit the control space 50 and in this case the second pressure surface 48 likewise restricts the control space 50 in the displacement direction of the pressure piston 45. In this case, the pressure piston 45 and the pressure tank 44 are formed such that no connection is made between the two pressure spaces 49, 50 in the pressure accumulator 43. In the case of this embodiment, no pressure medium exchange is made between the pressure spaces 49 and 50 for leakage prevention. In the illustrated embodiment, the pressure surfaces 47, 48 are offset from one another in the displacement direction of the pressure piston 45, in which case the first pressure surface 47 is perpendicular to the displacement direction of the pressure piston 45 And is surrounded by the second pressure surface 48 in the plane. The first pressure surface 47 is formed in a circular shape, and the second pressure surface 48 is formed in an annular shape. Since the pressure piston 45 is displaced against the force of the spring member 46 by supplying the pressure medium to the pressure spaces 49 and 50, the volume of the pressure spaces 49 and 50 increases. The path through which the pressure piston 45 can be displaced against the spring member 46 is limited by the stop portion 54 formed in the pressure tank 44. [ The stopper 54 is disposed so that the storage space 49 is not connected to the control space 50. [

The spring member 46 is supported on the side of the pressure piston 45 opposite the pressure spaces 49 and 50 on the one hand and on the side of the pressure tank 44 opposite the pressure spaces 49 and 50 on the other hand. In this case, since the spring member 46 is pre-stressed and assembled in the pressure accumulator 43, the volume of the pressure space 49, 50 is minimized when the system pressure is low. In this embodiment, the side surface of the pressure piston 45 opposite to the spring member 46 abuts against the pressure tank 44.

The area of the pressure tank 44 opposite to the pressure surfaces 47 and 48 is formed as a pressure space (back pressure space 58). In this case, the surface of the pressure piston 45 at the back pressure space 58 serves as the back pressure surface 59. By supplying the pressure medium to the back pressure space 58, a force parallel to the force of the spring member 46 acts on the pressure piston 45 through the back pressure surface 59. In the illustrated embodiment, the back pressure surface 59 is formed flat and oriented perpendicular to the direction of motion of the pressure piston 45. It is also conceivable that the surface or back pressure surface 59 includes additional functional elements so that the surface is not flat. A retaining portion for the spring member 46 may be formed on the back pressure surface 59, for example.

The storage space 49 is connected to the pressure medium supply device 37 by the storage line 51. The storage line 51 flows into the pressure medium supply device 37 from the rear of the check valve 42a when viewed in the flow direction on the one hand and into the storage space 49 by the port 56 on the other hand. The storage line is provided with a check valve 42c which permits the flow of the pressure medium from the storage space 49 to the pressure medium supply device 37 and prevents the opposite pressure medium flow. Therefore, the pressure peak generated in the actuating device 10a, b does not reach the storage space 49 of the pressure accumulator 43 and is retained on the check valve 42c. This increases the hydraulic stiffness of the device 10. [

Optionally, the control space 50 may be connected to the tank 39 or to the pressure source by a control line 52. In the illustrated embodiment, the pressure medium pump 38 of the pressure medium supply device 37 is used as the pressure source. However, it is equally possible to use other pressure sources, such as the pressure medium pump 38 of a servo consuming device such as a power steering system. In this case, the pressure medium discharged from the control space 50 is not guided into the tank 39 of the lubricant circuit of the internal combustion engine 1 but is guided to the corresponding tank 39 of the servo consuming device. The control line 52 is provided with an additional check valve 42b for preventing the backflow of the pressure medium from the control space 50 to the pressure medium supply device 37. [

In order to control the flow of the pressure medium directed toward or out of the control space 50 and the flow of the pressure medium directed into the back pressure space 58 or discharged from the back pressure space, (60) is provided. The directional control valve 53 is formed as a 4/2 directional control valve and includes a pressure port P ₁ , two operation ports A ₁ and B ₁ and a tank port T ₁ . The pressure port P ₁ is connected to a pressure source and in the illustrated embodiment is connected to the pressure medium supply 37 via a control line 52. The third operation port A ₁ is connected to the control space 50 and the fourth operation port B ₁ is connected to the back pressure space 58 and the tank port T ₁ is connected to the tank 39 . In the first control position of the directional control valve 53 the third operating port A ₁ is connected to the pressure port P ₁ while the fourth operating port B _{1 is} connected to the tank port T ₁ do. In the second control position of the directional control valve 53 the third operating port A ₁ is connected to the tank port T ₁ while the pressure port P _{1 is} connected to the fourth operating port B ₁ do.

The control line flows from the rear of the directional control valve 53 through the second port 56 into the control space 50. [ Also provided is a connection line 55 connecting the control line 52 to the storage line 51. The connection line 55 is introduced into the storage line 51 on the one hand between the check valve 42c and the first port 56 of the storage space 49 and on the other hand the control valve 53, And into the control line 52 between the second port 56 of the control circuit 50. The connecting line 55 is provided with an additional check valve 42d that allows the pressure medium flow from the control line 52 to the storage line 51 and prevents the opposite pressure medium flow.

The control valve 40 is in the second (intermediate) position and the directional control valve 53 is in the first position when the adjustment request is not transmitted from the engine control unit to the device 10 during the operation of the internal combustion engine 1 have. Therefore, the pressure medium does not flow toward the operating device 10a or from the operating device. The pressure medium flow from the pressure medium supply device 37 to the storage space 49 via the storage line 51 is prevented by the check valve 42d. The pressure medium is supplied to the control space 50 by the control line 52 and the directional control valve 53. [ At the same time, the pressure medium reaches the storage space 49 by the control line 52, the connection line 55 and the storage line 51. At the same time, the back pressure space 58 is connected to the tank 39 by the directional control valve 53. The pressure medium flowing into the storage space 49 or the control space 50 acts on the first or second pressure surfaces 47 and 48 so that the pressure piston 45 is stopped against the force of the spring member 46, The volume of the storage space 49 as well as the control space 50 increases. At the same time, the back pressure space 58 is vented into the tank 39. When the phase angle adjustment is requested from the engine control unit, the control valve 40 is switched to the first or third position of the control valve. As a result, the pressure medium reaches the first or second pressure chamber 35, 36 from the pressure medium pump 38, so that the phase is adjusted by the actuating device 10a, b. The directional control valve 53 is switched to its second control position if the volume flow delivered from the pressure medium pump 38 must reach a regulating speed that is too low or too high to ensure regulation. In the control position, the control space 50 is connected to the tank 39. As a result, the pressure medium under pressure in the control space 50 is connected to the atmospheric pressure, so that the control space 50 is quickly evacuated. At the same time, the storage space 49 is emptied into the pressure medium supply device 37. The pressure medium in the control space 50 is quickly evacuated so that the pressure piston 45 is only supported against the storage space 49 by the first pressure surface 47, (49). Therefore, the pressure p in the storage space 49 at the beginning of the evacuation process is added to the pressure formed by the filling of the back pressure chamber 58, as follows.

This is the case when the pressure piston 45 has not yet been deflected completely, that is, when the stopper 54 is not in contact. In this case, p _sys corresponds to the system pressure of the pressure medium supply device 37 that was provided at the beginning of the discharge of the pressure accumulator 43. Since the check valve 42a is disposed in front of the storage line 51 in the pressure medium line 41 in the flow direction, the total pressure p and the total volume of the storage space 49 are equal to the volume of the operating device 10a And is not discharged to the oil passage of the internal combustion engine 1. Thus not only is the present system pressure provided, as in the example with a conventional pressure accumulator, but also a pressure which is increased by the factor 1 + A ₂ / A ₁ is also provided.

In addition, the pressure medium is guided from the control line 52 to the back pressure space 58. The pressure medium supplies a force acting in the same direction as the direction of the spring member (46) to the back pressure surface (59) of the pressure piston (45). Therefore, the pressure in the storage space 49 further rises.

Thereby, the pressure medium supply device 37 is subjected to pressure support by setting the first directional control valve 53 to the second control position, and the pressure support is provided by a conventional pressure accumulator. Therefore, when the adjustment speed of the actuating device 10a is significantly increased or the adjustment speed is the same, the actuating device 10a can be implemented smaller if the size setting is the same, since the pressure medium pump 38 ).

Embodiments in which the connection line 55 is omitted and the check valve 42c is not disposed in the storage line 51 can also be considered. The pressure accumulator 43 is filled by the storage space 51 and the control line 52 in the operating phase of the internal combustion engine 1 where the phase position is kept constant. When the system pressure drops, the pressure medium is not discharged from the control space 50. Whereby the volume of the control space 50 and the storage space 49 is kept constant despite the pressure drop in the pressure medium supply device 37. In this case, the following equation applies to the path (x) where the pressure piston 45 has been deflected from its starting position.

Where A ₁ corresponds to the area of the first pressure surface 47, A ₂ corresponds to the area of the second pressure surface 48, p _max corresponds to the system pressure that occurs most during the filling step, D corresponds to the spring constant of the spring member 46. At this time, the maximum displacement path is limited by the stops 54. When the directional control valve 53 is switched to the second control position, the pressure p provided from the pressure accumulator 43 when the pressure piston 45 is not yet fully deflected is generated by the filling of the back pressure space 58 The following equation is added to the pressure.

In order to realize the pressure rise, the following equation should be applied to the ratio (Q _D / Q _V ) of the pressure medium flow discharged from the control space 50 to the pressure medium flow discharged from the storage space 49.

To achieve this, the following equation applies for the minimum perfusion cross-section (A _D ) between the control space 50 and the tank 39:

In the above equation, A _V corresponds to the minimum perfusion cross-section between the storage space 49 and the actuating device 10a or between the actuating device 10a and the tank 39.

One or more additional actuating devices 10b and 10c in addition to the first actuating device 10a can be controlled by the pressure medium supply device 37 via additional pressure medium lines 41 and further control valves 40 You can also think about the point. At this time, the additional operation device 10b can also receive support from the pressure accumulator 43. [ To this end, the branch towards the actuating device 10b is located behind the check valve 42a in the flow direction. If the pressure accumulator 43 has to support only the first actuating device 10a, the branch towards the additional actuating device 10c must be placed in front of the check valve 42a in the flow direction.

It is also conceivable that the check valve 42a is arranged behind the branch from the flow direction to the storage line 51 as well. In this case, a pressure peak is reserved between the actuating device 10a, b and the branch towards the storage line 51. [ As a result, the pressure peak does not reach the pressure accumulator 43, so that a more stable torque transmission is achieved through the actuating device 10a, b. It is also conceivable that one check valve 42a is inserted in each of the pressure medium lines 41 in front of and behind the branch from the flow direction toward the storage line 51. In this case, stable torque transmission is achieved not only through the actuators 10a, b, but also the pressure medium volume or pressure in the storage space 49 is prevented from being discharged into the oil passage of the internal combustion engine 1.

The entire pressure medium line 41 in which the check valve 42b and / or the check valve 42a are disposed may be omitted between the inflow points of the pressure accumulator 43 .

Figure 4 shows another embodiment of the device 10 according to the invention. In this embodiment, the pressure piston 45 of the pressure accumulator 43 separates the pressure tank 44 into the storage space 49 and the back pressure space 58, in which case the control space 50 is not provided. The storage space 49 is limited by the first pressure surface 47 in the displacement direction of the pressure piston 45 and the back pressure space 58 is restricted by the back pressure surface 59. [ The storage space 49 can be supplied with the pressure medium supplied from the pressure medium supply device 37 via the storage line 51. The back pressure space 58 may be connected to the pressure source by a control line 52. In the illustrated embodiment, the control line is introduced into the pressure medium supply device 37. Whereby the control line 52 is connected to the pressure medium pump 38 of the internal combustion engine 1. Alternatively, other pressure sources may be used, such as a pressure medium pump of a servo consuming device. The control line 51 is provided with a directional control valve 53 formed as a 3/2 switching valve. The directional control valve 53 includes a pressure port P ₁ , an operation port B ₁ and a tank port T ₁ . The pressure port P ₁ is connected to the pressure medium pump 38 and the operation port B ₁ is connected to the back pressure chamber 58 and the tank port T ₁ is connected to the tank 39. Operation port in a first control position of the directional control valve (53) (B ₁₎ is any one of the tank ports while connected to (T _1), the pressure port (P ₁₎ is different from the port (B _1, T ₁₎ port Lt; / RTI > When the directional control valve 53 is in the control position, the back pressure space 58 is connected to the tank 39. Working port in the second control position of the directional control valve (53) (B ₁₎ is any of the pressure port, while the connection to the (P _1), a tank port (T ₁₎ is the other port (B _1, P ₁₎ port Lt; / RTI > When the directional control valve 53 is in the control position, the back pressure space 58 receives the pressure medium from the pressure medium pump 38. The directional control valve 53 is in the first control position during the filling of the pressure accumulator 43. [ The pressure medium is provided in the storage space (49). As a result, the pressure piston (45) is displaced against the force of the spring member (46). The volume of the storage space 49 is enlarged as much as the volume of the back pressure space 58 is reduced. The directional control valve is in the second control position in the pressure support phase. In this position, a pressure medium is provided in the back pressure space 58, and the pressure medium acts on the back pressure surface 59. The pressure formed therefrom increases the force exerted on the pressure piston (45) from the spring member (46). As a result, the supporting pressure provided from the storage space 49 of the pressure accumulator 43 rises. An embodiment in which the area of the back pressure surface 59 exceeds the area of the first pressure surface 47 may be considered. Thus reaching a pressure ratio that acts as a positive value on the pressure value that can be provided.

Figure 5 shows another embodiment of the device according to the invention. Substantially the above embodiment corresponds to the embodiment shown in Fig. Unlike the embodiment of Fig. 4, one check valve 42b, c, is disposed in the storage line 51 and the control line 52, respectively. The directional control valve is also formed as a 4/2 directional control valve, in which case an additional operating port A ₁ is connected to the storage space 49. At the first control position of the directional control valve 53, the further operating port A ₁ is connected to the pressure port P ₁ . In the second control position of the directional control valve 53, the actuating port A ₁ is not connected to any of the other ports B ₁ , P ₁ , T ₁ . In this embodiment, the pressure medium reaches the storage space 49 from the pressure medium pump 38 through the control line 52 and the directional control valve 53, as long as the directional control valve is in the first control position. At the same time, the back pressure space 58 is vented into the tank 39. When the directional control valve 53 is in the second control position, the operation port A ₁ is closed and the back pressure space 58 is supplied with the pressure medium from the pressure medium pump 38. At the same time, the storage space 49 is emptied into the pressure medium supply device 37. The check valve 42c lubricates the pressure accumulator 43 against the pressure peaks generated in the actuators 10a, b.

In all of the embodiments shown, a pressure accumulator 43 is introduced into the pressure medium line 41 connecting the control valve (s) 40 and the pressure medium pump 38. It is likewise conceivable that the pressure accumulator (s) 43 are introduced into the pressure medium line 41 connecting the actuating devices 10a, b and the control valve (s)

In addition to using the pressure accumulator 43 for application for variable control of the control time in the internal combustion engine 1, this pressure accumulator 43 can be used in another vehicle sector, for example in a switchable cam follower, It may also be used in the field of transmissions.

1: Internal combustion engine
2: Crankshaft
3: Piston
4: Cylinder
5: Traction drive
6: intake camshaft
7: exhaust camshaft
8: Cam
9a: Intake gas exchange valve
9b: Exhaust gas exchange valve
10: Device
10a: First operating device
10b: Additional operating device
21: Chain wheel
22: outer rotor
22a: housing
23: Internal rotor
24: side cover
25: side cover
26: Hub member
27: Vane
27a: Vane spring
28: Vane groove
29:
30:
32: Fixing member
33: hollow space
34:
34a:
34b:
35: first pressure chamber
36: Second pressure chamber
37: Pressure medium supply
38: Pressure medium pump
39: Tank
40: Control valve
41: pressure medium line
42a: Check valve
42b: Check valve
42c: Check valve
42d: Check valve
43: Pressure accumulator
44: Pressure tank
45: Pressure piston
46: spring member
47: first pressure side
48: second pressure face
49: Storage space
50: control space
51: storage line
52: control line
53: Directional control valve
54:
55: connection line
56: Port
58: backpressure space
59: back pressure side
60: control means
A: First operating port
B: Second operating port
P: Supply port
T: exhaust port
A ₁ : Third operating port
B ₁ : Fourth operation port
P ₁ : Pressure port
T ₁ : Tank port

Claims (10)

An apparatus (10) for variably adjusting the control time of the gas exchange valves (9a, b) of the internal combustion engine (1)
At least one pressure chamber (35, 36), a pressure medium supply device (37) and at least one pressure accumulator (43)
The pressure medium supply device 37 can supply pressure medium to one or more pressure chambers 35, 36 or discharge pressure medium from the pressure chamber,
The phase position of the output member 23 with respect to the driving member 22 may fluctuate by supplying the pressure medium to the pressure chambers 35 and 36 or discharging the pressure medium from the pressure chamber,
The pressure accumulator 43 comprises a displaceable member 45 having a first pressure surface 47 that partially limits the storage space 49,
The storage space 49 may be connected to or connected to the pressure medium supply device 37,
The energy accumulator supplies force to the displaceable member 45 in the direction of the starting position,
The displaceable member 45 may be displaced against the force of the energy accumulator 46 by being supplied with pressure in the storage space 49. In the apparatus for varying the control time of the gas exchange valve of the internal combustion engine ,
The displaceable member 45 includes a back pressure surface 59 at least partially restricting the back pressure space 58 so that the displaceable member 45 is supplied in the back pressure space 58 in the direction of the starting position (10) for varying the control time of the gas exchange valve of the internal combustion engine. 2. The apparatus according to claim 1, wherein the displaceable member (45) comprises at least one second pressure surface (48) that partially limits the control space (50) 45 is displaced against the force of the pressure accumulator 46 and the pressure medium flow from the reservoir space 49 into the control space 50 within the pressure accumulator 43 is blocked. An apparatus (10) for varying the control time of a gas exchange valve of an engine. The internal combustion engine according to claim 2, characterized in that the displaceable member (45) is displaced in the same direction as the pressure medium is supplied to the control space (50) by supplying the pressure medium to the storage space (49) (10) for varying the control time of the gas exchange valve of the gas exchange valve. A device according to claim 1, characterized in that the back pressure space (58) can be selectively connected to the pressure source (38) or to the tank (39) 10). 3. A system according to claim 1 or 2, characterized in that a control means (60) is provided in which the back pressure space (58) can be selectively connected to the tank (39) (10) for varying the control time of the gas exchange valve of the internal combustion engine. An apparatus (10) for variably adjusting the control time of a gas exchange valve of an internal combustion engine, characterized in that the back pressure space can be connected to a pressure medium pump (38) of the internal combustion engine (1). An apparatus (10) for variably adjusting the control time of a gas exchange valve of an internal combustion engine, characterized in that the back pressure space can be connected to the tank (39) of the internal combustion engine (1). 6. A device according to claim 5, characterized in that a directional control valve (56) comprising a pressure source (38), a tank (39) and a respective port (G, B, T) connected to the back pressure space (10) for varying the control time of the gas exchange valve of the internal combustion engine. The control valve according to claim 8, characterized in that the directional control valve (56) comprises an additional port (A) connected to the storage space (49) or the control space (50) An apparatus (10) for variable adjustment. A device according to claim 2, characterized in that the storage space (49) and the control space (50) are not connected to each other in the pressure accumulator (43) 10).

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