KR101468262B1 - Apparatus for variably adjusting the control times of gas exchange valves in an internal combustion engine - Google Patents

Abstract

An apparatus for variably adjusting the 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 pressurized medium supply device allows pressurized medium to be fed to or discharged from the at least one pressure chamber. A phase angle of the output element relative to the driving element can be changed by supplying 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 connected to the pressurized medium supply device. The movable element can be moved against the force of an 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, the storage space being connected to the pressure medium supply device, Whereby the displaceable member is displaced against the force of the energy accumulator .

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. The pressure medium pump should therefore be constructed in such a way that the pressure medium pump can sufficiently provide the system pressure even 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 adapted accordingly to ensure the required regulating speed even in the worst pressure conditions, for example at high pressure medium temperatures and / or low rotational speeds. 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 is disposed between the pressure medium pump and the control valve, the pressure accumulator being connected to the pressure medium supply device. 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 providing a method of controlling a displaceable member comprising at least one second pressure surface in which a displaceable member partially restricts the control space and by supplying pressure to the control space the displaceable member can be displaced against the force of the energy accumulator Which is achieved by preventing the flow of pressure medium from the reservoir to the control space inside the pressure accumulator.

In this regard, it may be provided that the storage space and the control space are not connected to each other inside the pressure accumulator.

The displaceable member can be formed, for example, as a pressure piston that can be displaced against the force of an energy accumulator formed as a spring member inside the pressure tank. Also, according to an alternative embodiment thereto, another type of energy accumulator, for example a body made of an elastomer and capable of reversible deformation, or a gas pocket filled with gas, may be used. 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, through a pressure medium channel which is provided in the housing of the pressure accumulator or inside the pressure piston and in 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.

If 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,

).

The present invention is based on a device 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 In which case the pressure medium may be supplied to the at least one pressure chamber by means of the pressure medium supply device or the pressure medium may be discharged from the pressure chamber, thereby supplying the pressure medium to the pressure chamber or discharging the pressure medium from the pressure medium The phase position of the output member relative to the member may vary and the displaceable members of the pressure accumulator may be formed independently of each other to limit the two or more spaces that can be supplied with pressure to the direction of displacement of the member. Wherein at least one of the spaces (storage space) is connected to the pressure medium supply device and can thereby be emptied into the pressure medium supply device during the phase adjustment process. In addition, the one or more additional spaces (control spaces) are similarly supplied with the pressure medium during the filling of the storage space, and are emptied faster than the storage space during the emptying of the storage space. This can be done for example in the tank against atmospheric pressure. Thereby, the control space supports the filling process in such a way that the more displaceable member is more strongly deflected in the case where no pressure medium supply to the control space is made.

Due to the pressure increase provided by the pressure accumulator, the pressure accumulator can suppress the maximum consumption, so that the pressure medium pump can be configured to conform to the normal operation of the internal combustion engine. In short, there is no need for a pressure medium pump that is set or adjusted to an oversize to ensure absolute safe and rapid adjustment to the phase position. In addition, the adjustment speed of the operating device increases. Thus, according to an alternative embodiment, the size of the operating device can be set to be smaller while the adjustment speed remains the same. By doing so, mass, mass moment of inertia and cost can be reduced.

According to an improved embodiment of the present invention, the control space may be selectively connected to a pressure source or tank during operation 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 control space, and the other control means blocks the connection portion from the control 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 the pressure accumulator is filled or emptied according to these control signals. A variety of support strategies can be realized thereby. 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.

According to an embodiment embodying the invention, the control space may be emptied into the tank without a bypass path through the consumable device. At this time, the control space is preferably emptied through the proportional valve or the switching valve against atmospheric pressure.

According to an improved embodiment of the invention, a control means is provided, whereby the control space can be selectively connected to the tank or the pressure source by the control means. The control means may be formed, for example, as a directional control valve.

In accordance with an alternative embodiment of the present invention, there is provided a control means which, in a first state, interrupts the flow of the pressure medium from the storage space towards the pressure medium supply device, And in a second state allows pressure medium flow from the storage space to the pressure medium supply device and provides a connection between the control space and the tank without a bypass path through the consumable device. In this regard, the storage space and the control space are connected via a check valve, a connection is arranged between the control means and the spaces, and the check valve blocks the pressure medium flow from the storage space to the control space.

Accordingly, in the operation steps of the internal combustion engine in which the phase adjustment is not performed, but the system pressure is reduced, the storage space is prevented from being connected to the pressure medium supply device. Whereby the pressure in the storage space and the volume of the pressure medium are maintained at a high value.

In this connection, a storage line connecting the storage space and the pressure medium supply device, and a control line connecting the pressure source and the control space may be provided. In addition, the control means may be formed as a single directional control valve including a storage line, a control line, a control space, a storage space and a respective port for the tank. In doing so, the number of components and control related complexity during operation of the internal combustion engine is reduced. According to an alternative embodiment, the control means may comprise at least one first directional control valve disposed in the control line. In addition, the control means may comprise a second directional control valve disposed in the storage line. In this regard, the directional control valves may be formed, for example, as a switching or proportional valve. In accordance with this alternative embodiment, the control means may also comprise a check valve which can be arranged and released in the storage line.

Preferably, in the apparatus herein, a check valve may be provided between the control space and the pressure source, such that the check valve blocks the pressure medium flow from the control space toward the pressure source direction. Whereby the volume of the pressure medium located in the control space is surrounded until it is connected to the tank. By doing so, even if the system pressure drops, the displaceable member is held in the biased position, thereby preventing the storage space from being emptied in an undesirable manner.

According to an improved embodiment of the present invention, a check valve may be provided between the storage space and the pressure medium supply device to block the flow of the pressure medium from the pressure medium supply device toward the storage space. By doing so, the pressure peak generated in the operating device is prevented from being transmitted into the pressure accumulator. As a result, the pressure medium flowing back from the pressure chamber of the actuating device during the pressure peak is released from the check valve, thereby increasing the hydraulic stiffness of the device of the present invention, thereby increasing the speed of adjustment, and torque transmission from the crankshaft to the camshaft Is improved.

In other words, the pressure support of the pressure accumulator can 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. In this case, the pressure provided by the pressure accumulator may correspond to a value that may correspond to a maximum of 1 + A ₂ / A ₁ , multiplied by the present system pressure, or the same factor, depending on each embodiment, It corresponds to the value multiplied by the maximum system pressure. The complete factor (1 + A ₂ / A ₁ ) is always used when all the storage capacities of the energy accumulator have not yet been fully used, that is, when the spring member is not yet compressed into the block or the pressure piston is still in contact with the stop exist. According to an improved embodiment of the invention, the displaceable member comprises a third pressure surface at least partially restricting the counter-pressure space, wherein when the pressure medium is supplied to the back pressure space, The displaceable member is displaced in the opposite direction, such as when the pressure medium is supplied to the space. As a result, the force applied to the displaceable member from the energy accumulator rises by a force caused by the pressure acting on the third pressure surface, so that the pressure that can be provided from the pressure accumulator rises again.

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.

According to an embodiment embodying the present invention, the ratio between the control space and the minimum cross-sectional area between the tank and the storage space and the minimum cross-sectional area between the operating device is greater than the ratio between the area of the second pressure surface and the area of the first pressure surface .

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.
3 is a diagram showing a first embodiment of the apparatus of the present application.
Figures 4-12 are views of further embodiments of the apparatus of the present application.

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, c 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.

Figure 3 shows a first embodiment of the device 10 according to the invention with actuating devices 10a, b, c, a pressure medium supply device 37 and a pressure accumulator 43. [ Figures 2a and 2b show the actuating devices 10a, b and c respectively in longitudinal and transversal sections. The actuating devices 10a, b, c include 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, c, a hollow space 33 is formed between two protruding portions 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, c and the pressure chambers 35, 36 connected to the supply port P by this pressure peak are empty for 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 adjustment speed of the actuators 10a, b, c 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 a pressure medium pump 38 is used that is configured to meet the maximum requirements of the actuating devices 10a, b, c, and thus set to an oversize size during most of the operating stages of the internal combustion engine 1. 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 the second pressure surface 48 also limits the control space 50 with the pressure tank 44. At this time, the pressure piston 45 and the pressure tank 44 are formed in such a manner that there is no connection between the two spaces 49, 50 inside the pressure accumulator 43. Depending on the illustrated embodiment, the displacement path of the pressure piston 45 is limited by the stops 54. The storage space 49 is connected to the pressure medium supply device 37 by a storage line 51 and the storage line 51 is connected to the pressure medium supply device at the back of the check valve 42a do. The control space 50 can optionally be connected to the tank 39 or to the pressure source by a control line 52. In the illustrated embodiment, the pressure medium supply device 37 is used as the pressure source. It is likewise conceivable, however, to use another pressure source, such as, for example, the pressure medium pump 38 of the servo consuming device of the power steering system. In this case, the pressure medium discharged from the control space 50 is not guided to the tank 39 of the lubricating oil circuit of the internal combustion engine 1, but is guided to the corresponding tank 39 of the servo consuming device.

A control means 60 is provided in the form of a first directional control valve 53 for controlling the flow of the pressure medium directed into or out of the control space 50. The first directional control valve 53 includes a pressure port P ₁ , a control space port A ₁ and a discharge 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 control space port A ₁ is connected to the control space 50 and the discharge port T ₁ is connected to the tank 39. In the first control position of the first directional control valve 53, the control space port A ₁ is connected to the pressure port P ₁ while the discharge port T _{1 is} connected to the other ports P ₁ , A ₁ ) Are not connected to any of the ports. In the second control position of the first directional control valve 53, the control space port (A ₁₎ has a discharge port (T _1), while coupled to the pressure port (P ₁₎ is the other ports (T _1, A ₁ ) Are not connected to any of the ports.

In addition, an additional check valve 42b is provided, which is disposed in the control line 52 to prevent the pressure medium from flowing backward from the control space 50 into the pressure medium supply device 37. The control valve 40 is located in the second (intermediate) position and the first directional control valve 53 (middle) is in the second (middle) position if no adjustment requests from the engine control unit are delivered to the present apparatus 10 during operation of the internal combustion engine 1. [ Is located in the first position. As a result, the pressure medium does not flow to or from the operating device 10a. At the same time, the pressure medium not only reaches the storage space 49 through the storage line 51 but also reaches the control space 50 via the control line 52. The pressure medium introduced into the reservoir space 49 or the control space 50 acts on the pressure surface 47 or on the pressure surface 48 so that the pressure piston 45 is stopped against the force of the spring member 46, The volume of the control space 50 and the storage space 49 is increased. If the pressure in the pressure medium supply device 37 drops, the pressure in the storage space 49 also drops to the same degree. The check valve 42b in the control line 52 is closed based on the pressure drop between the control space 50 and the pressure medium supply device 37 so that the pressure drop in the control space 50 and the pressure drop in the control space 50 Is prevented. 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 stop 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. Here, the stop position means the state of the pressure piston 45 in which the spring member 46 is relaxed as much as possible.

If phase angle adjustment is required by the engine control unit, the control valve 40 is switched to its first or third position. The pressure medium thereby reaches the first or second pressure chamber 35, 36 from the pressure medium pump 38, so that the phase adjustment is caused by the actuating device 10a, b, c. If the volume flow delivered from the pressure medium pump 38 is too low or too high to guarantee an adjustment, then the first directional control valve 53 is switched to its second control position . In this control position, the control space 50 is connected to the tank 39. So that the pressure medium existing under pressure in the control space 50 is connected to the atmospheric pressure, whereby the control space 50 is quickly emptied. At the same time, the storage space 49 is emptied into the pressure medium supply device 37. If the pressure medium in the control space 50 is quickly evacuated in such a way that the pressure piston 45 is supported only against the reservoir space 49 through the first pressure surface 47, And acts only on the space 49. The pressure p existing in the storage space 49 at the start time of the evacuation process is set to be equal to or less than the pressure p in the storage space 49 as long as the pressure piston 45 is not yet fully deflected, The formula is applied.

Since the check valve 42a is disposed in front of the storage line 51 in the flow direction in the pressure medium line 41, the total pressure p and the total volume of the storage space 49 are equal to the total volume of the operating device 10a And is not discharged to the oil passage of the internal combustion engine 1 is ensured. Thus not only the current system pressure or the maximum filling pressure is provided, but also the pressure which is increased by the factor 1 + A ₂ / A ₁ is also provided, as in the case of use with a conventional pressure accumulator. Whereby the pressure medium supply device 37 is able to receive pressure support by adjusting the second control position at the first directional control valve 53. [ Further, when the size setting is the same, the adjustment speed of the operation device 10a can be significantly raised, or, when the adjustment speed is the same, the operation device 10a can be implemented smaller, Without taking into account the disadvantages of the medium pump 38.

Likewise, an embodiment in which the check valve 42b is not disposed on the control line 52 can be conceived. In the operating phase of the internal combustion engine 1 in which the phase position is kept constant, the pressure accumulator 43 is filled similar to the previously described embodiment. When the system pressure drops, the pressure medium is discharged not only from the storage space 49 but also from the control space 50. This causes a pressure drop in the two spaces 49, 50, which displaces the pressure piston 45 in the direction of the stop position of the pressure piston. Thereby reducing the pressure medium volume that can be provided for phase adjustment as well as the pressure that can be provided in the storage space 49 according to this embodiment. However, when the first directional control valve 53 is switched to the second switching position, a pressure rise is initiated in the storage space 49. In this case, the following equation applies for the pressure p provided when the pressure piston 45 is not yet fully deflected.

In the above equation, p _sys corresponds to the system pressure present at the start of pressure support. In this regard, it may be conceivable to use the present embodiment in the internal combustion engine 1 where the required maximum system pressure exceeds the capacity of the pressure medium pump 38 only to a very small extent. In this case, it is not necessary to dispose the check valve 42b in the control line 52, thereby saving the cost.

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.

In order to ensure the functionality of the pressure accumulator 43, an air outlet 46a of the spring space is provided toward the tank 39 side.

It is also conceivable that the check valve 42a is arranged in the rear of the branch from the flow direction to the storage line 51 (Fig. 4). 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 to insert the check valve 42a in the pressure medium line 41, respectively, in front of and behind the branch from the flow direction to the storage line 51 (Fig. 5). 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.

A further embodiment of the device 10 according to the invention is shown in Fig. Unlike the embodiment shown in FIG. 3, an additional check valve 42c is disposed in the storage line 51 in this embodiment. This check valve 42c prevents the flow of the pressure medium from the pressure medium supply device 37 to the storage space 49 so that the pressure peaks generated in the actuating devices 10a, It does not reach the storage space 49 of the check valve 42 and is reserved at the check valve 42c. So that the hydraulic stiffness of the device 10 rises similarly to the embodiment according to Fig. A connection line 55 is provided to fill the reservoir 49 of the pressure accumulator 43 and this connection line is connected between the pressure source 38 and the first directional control valve 53 And flows into the storage line 51 between the check valve 42c and the storage space 49 on the other side. In this connection, an additional check valve (not shown) is provided in the connection line 55 to prevent the pressure medium discharged from the storage space 49 from flowing between the pressure medium pump 38 and the check valve 42a to the pressure medium supply device 37 (42d) can be disposed. According to a slightly modified example of this embodiment, among all the inflow points of the pressure accumulator 43, all of the pressure medium line 41 and / or the check valve 42b in which the check valve 42a is disposed are also omitted .

7-11, respectively, further embodiments of the present invention for device 10 are shown. In these embodiments, the control means 60 are provided on the storage line 51 as well as the control line 52. [ The control means 60 can block the perfusion of the pressure medium in at least one direction.

According to the embodiment shown in Fig. 7, only one control valve in the form of a directional control valve 56 is provided. The directional control valve 56 includes a pressure port P ₁ , a control space port A ₁ , a storage port V ₁ , a storage space port B ₁ and a discharge port T ₁ . The pressure port P ₁ and the storage port V ₁ are connected to a pressure source and connected to the pressure medium supply device 37 via control line 52 or storage line 51, do. The control space port A ₁ is connected to the control space 50 and the storage space port B ₁ is connected to the storage space 49 and the discharge port T ₁ is connected to the tank 39. In addition, the liquid is introduced into the control line 52 between the directional control valve 56 and the control space 50 on one side and flows into the storage line 51 between the directional control valve 56 and the storage space 49 on the other side. A connection line 55 is provided. In this connection line 55, a check valve 42d is arranged to prevent the flow of the pressure medium from the storage line 51 to the control line 52. [ In the first control position of the directional control valve 56 only the control space port A ₁ is connected to the pressure port P ₁ while all other ports B ₁ , T ₁ and V ₁ are closed. In the second control position of the directional control valve 56 the storage port V _{1 is} connected to the storage space port B ₁ and the control space port A ₁ is connected to the tank port T ₁ , The port P ₁ is not connected to any of the other ports A ₁ , B ₁ , T ₁ , and V ₁ .

If the adjustment request is not transmitted to the device 10 by the engine control unit during operation of the internal combustion engine 1, the directional control valve 56 is placed in the first control position. In this state, the pressure medium is supplied from the pressure medium supply device 37 to the control space 50 through the control line 52 and the direction control valve 56. At the same time, the storage space 49 is filled through the connection line 55 as well. In this state, the pressure accumulator 43 behaves similarly to the pressure accumulator 43 shown in Fig. The pressure piston 45 is displaced against the force of the spring member 46 and the spaces 49 and 50 are filled with the pressure medium. If the pressure of the pressure medium supply device 37 is reduced, the pressure in the control space 50 also decreases. However, the storage space 49 maintains a high pressure condition because the storage space is isolated from the pressure medium supply device 37 by the directional control valve 56 on one side and by the check valve 42d on the other side to be. So that the pressure accumulator 43 maintains its own filled state. If the directional control valve 56 is switched to the second control state, the control space 50 on one side is emptied into the tank 39 and on the other side the storage space 49 is emptied into the pressure medium supply device 37 . This process is similar to the first embodiment (Fig. 3).

Fig. 8 shows a further embodiment according to the present invention which is different from the above-mentioned embodiments only in the arrangement of the check valve 42a. In this regard, the check valve 42a is arranged similar to the embodiment according to Fig. Also contemplated is an embodiment similar to Fig. 5, which includes two check valves 42a disposed in front of and behind the storage line 51 in the flow direction, respectively.

Figs. 9-11 respectively show additional devices 10 according to the invention which are substantially the same as the devices according to Figs. 7 and 8. Fig. In contrast to the apparatus according to Figs. 7 and 8, the apparatuses 10 shown in Figs. 9 to 11 have only one control means 60 (according to the illustrated embodiment, (56), two control means 60 are provided. The first control means 60 controls the connection between the pressure medium supply device 37 and the storage space 49 while the second control means 60 controls the pressure medium supply device 37, ) And the tank 39. [0050]

According to the embodiment shown in Fig. 9, the first control means 60 is formed as a check valve 42e which can be released, and such a check valve is provided in the first control position from the pressure medium supply device 37, (49), but blocks the pressure medium flow in the opposite direction. The pressure medium flow in the second control position is allowed in both directions. In this case, the second control means 60 is the first directional control valve 53 shown in the first embodiment.

10 shows that, unlike the embodiment according to Fig. 9, the releasable check valve 42e can be replaced by a second directional control valve 57, in a particular embodiment with a 2 / Respectively. In the first control position, the second directional control valve 57 does not allow the pressure medium flow between the pressure medium supply device 37 and the storage space 49. At the second control position, the pressure medium can flow in both directions.

11, only the pressure medium flow from the pressure medium supply device 37 toward the control space 50 in the first control position is allowed, And the first directional control valve 53 is modified in such a manner as to be blocked by the one-way control valve 53. [

Fig. 12 shows a further view of the invention which is illustrated in accordance with the embodiment shown in Fig. It should be clearly appreciated that the above viewpoints can be used in all the embodiments mentioned above. The device 10 is characterized in that the connection line 55 between the first directional control valve 53 and the control space 50 is introduced into the control line 52 and the air outlet 46a of the spring space is not provided Which is different from the device 10 shown in Fig. Rather, the spring space is formed as a back pressure space 58 that can be filled with the pressure medium. The first directional control valve 53 has an additional back pressure port G connected to the back pressure space 58 according to the present embodiment. In the first control position of the first directional control valve 53, the control space port A ₁ is connected to the pressure port P ₁ while the back pressure port G is connected to the exhaust port T ₁ . In the second control position of the first directional control valve 53 the control space port A _{1 is} connected to the discharge port T ₁ while the pressure port P ₁ is connected to the back pressure port G. If the first directional control valve 53 is located at the first control position, no change occurs as compared with the embodiment according to Fig. In the second control position, however, the pressure medium is further guided into the back pressure chamber 58. The pressure medium supplies a force acting in the same direction as the spring member 46 to the third pressure surface 59 of the pressure piston 45. By doing so, the pressure in the storage space 49 is further raised.

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, c: 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
42e: Check valve which can be released
43: Pressure accumulator
44: Pressure tank
45: Pressure piston
46: spring member
46a: air outlet
47: first pressure side
48: second pressure face
49: Storage space
50: control space
51: storage line
52: control line
53: first direction control valve
54:
55: connection line
56: Directional control valve
57: second direction control valve
58: backpressure space
59: third pressure face
60: control means
A: First operating port
B: Second operating port
P: Supply port
T: exhaust port
P ₁ : Pressure port
T ₁ : exhaust port
A ₁ : Control space port
B ₁ : Storage port
V ₁ : Storage port
G: Back pressure port

Claims (18)

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 may supply the pressure medium to one or more pressure chambers 35, 36 or may discharge the 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 is connected to the pressure medium supply device 37,
By supplying pressure to the storage space 49, the displaceable member 45 can be displaced against the force of the energy accumulator 46, by means of a device for varying the control time of the gas exchange valve of the internal combustion engine As a result,
The displaceable member 45 comprises at least one second pressure surface 48 that partially limits the control space 50,
By supplying pressure to the control space 50, the displaceable member 45 can be displaced against the force of the energy accumulator 46,
An apparatus 10 for variably adjusting the control time of a gas exchange valve of an internal combustion engine, characterized in that the pressure medium flow from the storage space (49) to the control space (50) is blocked in the pressure accumulator (43) ). The control valve according to claim 1, characterized in that the control space (50) can be selectively connected to the pressure source (38) or the tank (39) during the operation of the internal combustion engine (10). The device according to claim 1, characterized in that the control space (50) can be evacuated into the tank (39) without a bypass path through the consuming device (10) for adjusting the control time of the gas exchange valve of the internal combustion engine ). 3. A device according to claim 2, characterized in that control means (60) are provided and the control space (50) can be selectively connected to the tank (39) or the pressure source (38) (10) for variably adjusting the control time of the gas exchange valve of the internal combustion engine. 3. The method of claim 2,
In the first state, the pressure medium flow from the storage space 49 to the pressure medium supply device 37 is blocked and the pressure medium flow to the storage space 49 and the control space 50 is allowed,
In an additional state, permits the flow of the pressure medium from the storage space 49 to the pressure medium supply device 37 and forms a connection between the control space 50 and the tank 39 without a bypass path through the consuming device
Characterized in that the control means (60) are provided for the control of the gas exchange valve of the internal combustion engine. 6. The apparatus according to claim 5, further comprising a storage line (51) connecting the storage space (49) and the pressure medium supply device (37), and a control line (52) connecting the pressure source (38) (10) for varying the control time of the gas exchange valve of the internal combustion engine. 7. A system according to claim 6, characterized in that the control means (60) comprises a single port (A ₁ ) for the storage line (51), a control line (52), a control space (50), a storage space (49) , B _1, P _1, T _1, V _1), only one device for adjusting the variable control times of gas exchange valves of an internal combustion engine, characterized in that formed as the directional control valve (56, 10 containing ). 7. A method according to claim 6, characterized in that the control means (60) comprises at least one first directional control valve (53) arranged in the control line (52) (10). 9. An internal combustion engine according to claim 8, characterized in that the control means (60) further comprises a second directional control valve (57) disposed in the storage line (51) or a check valve (10) for variably adjusting the control time of the gas exchange valve. 9. A control system according to claim 8, characterized in that the control means (60) further comprises a releasable check valve (42e) arranged in the storage line (51) (10). 6. The apparatus according to claim 5, wherein the storage space (49) and the control space (50) are connected via a check valve (42d) and a connection is arranged between the control means (60) and the spaces (49, 50) Wherein the check valve (42d) blocks the pressure medium flow from the storage space (49) to the control space (50). 2. A device according to claim 1, characterized in that a check valve (42b) for blocking the pressure medium flow from the control space (50) to the pressure source (38) is provided between the control space (50) and the pressure source (10) for variably adjusting the control time of the gas exchange valve of the internal combustion engine. 2. The apparatus according to claim 1, wherein a check valve (42c) for blocking the flow of the pressure medium from the pressure medium supply device (37) toward the storage space (49) is provided between the storage space (49) (10) for varying the control time of the gas exchange valve of the internal combustion engine. 2. The apparatus according to claim 1, wherein when the pressure medium is supplied to the storage space (49), the displaceable member (45) is displaced in the same direction as when the pressure medium is supplied to the control space (50) An apparatus (10) for varying the control time of a gas exchange valve of an internal combustion engine. 3. The apparatus according to claim 1, wherein the displaceable member (45) comprises a third pressure surface (59) at least partially restricting the back pressure space (58) 45) is displaced in a direction opposite to that in the case where the pressure medium is supplied to the control space (50) or the storage space (49). The apparatus for adjusting the control time of the gas exchange valve of the internal combustion engine 10). Method according to claim 2 or 5, characterized in that the ratio between the minimum perfusion cross section between the control space (50) and the tank (39) and the minimum perfusion cross section between the storage space (49) and the operating unit (10a, b) Is greater than the ratio between the area of the surface (48) and the area of the first pressure surface (47). A device according to claim 1, characterized in that the storage space (49) and the control space (50) are not interconnected within the pressure accumulator (43) (10). The device (10) according to claim 4, characterized in that the control means (60) is formed as a directional control valve (53).

Images