KR20100097117A - 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

Apparatus for variablely adjusting the control time of the gas exchange valve of an internal combustion engine {APPARATUS FOR VARIABLY ADJUSTING THE CONTROL TIMES OF GAS EXCHANGE VALVES IN 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, one or more pressure chambers, a pressure medium supply device, and one or more pressure accumulators. By means of the pressure medium supply device, a pressure medium may be supplied to or discharged from the pressure chamber, or the pressure medium may be supplied to or discharged from the pressure chamber. The phase position of the output member can vary, and the pressure accumulator includes a displaceable member having a first pressure surface that partially restricts the storage space, the storage space being connected to the pressure medium supply device, the pressure being stored in the storage space. By being supplied, the displaceable member can be displaced against the force of the energy accumulator. Can be.

In modern internal combustion engines, in order to be able to variably construct the phase relationship between the crankshaft and the camshaft in a defined angular range, i.e. between the maximum advance position and the maximum retard position, An apparatus for varying the control time of the exchange valves is used. Such a device typically includes an actuating device which is driven by the crankshaft and transmits the torque of the crankshaft to the camshaft. Here, inside the actuating device, a hydraulic actuator is formed which allows to influence the phase position between the crankshaft and the camshaft as desired. A pressure medium supply device is provided for supplying pressure medium to the operating device.

Devices of the aforementioned type are known, for example, from EP 1 025 343 B1. The device comprises two rotors that are rotatable with each other, wherein the outer rotor is driven in connection with the crankshaft, and the inner rotor is connected in a non-rotatable manner with the camshaft. The apparatus comprises a plurality of hollow spaces, each of which is divided by vanes into two interacting pressure chambers. The vanes are displaced inside the pressure chambers by supplying pressure medium to the pressure chambers or withdrawing the pressure medium from the pressure medium, whereby the rotation of the rotors and thus the rotation of the camshaft about the crankshaft as desired. Is done.

Supplying or evacuating the pressure medium to the pressure chambers is controlled by a pressure medium supply device comprising 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 medium line connects one of the working ports of the control valve to the pressure chambers. The pressure medium is typically provided from the lubricating oil circuit of the internal combustion engine.

To ensure the function of the device, the pressure in the pressure medium system must exceed a certain value in each operating stage of the internal combustion engine. This is particularly important in the idling stage of the internal combustion engine, 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, that is, the system pressure drops as the temperature rises. Thus, the pressure medium pump should be configured in such a way that the pressure medium pump can provide sufficient system pressure even in the worst 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 so as to ensure the required regulation speed even at the worst pressure conditions such as high pressure medium temperatures and / or low rotational speeds. As a result, pressure medium pumps are used, which are configured to meet the maximum requirements of the actuating device so that the size is set too large of most of the operating stages of the internal combustion engine. According to an alternative embodiment to this an adjustable pressure medium pump can be used which provides the pressure medium as required. The increased complexity in these two cases negatively impacts the cost, mounting space requirements and fuel consumption of the internal combustion engine.

Such a device is also known in another form in US Pat. No. 5,775,279 A. According to an embodiment of this publication, a pressure accumulator is arranged between the pressure medium pump and the control valve, which is connected to the pressure medium supply device. This pressure accumulator is filled with a pressure medium at high system pressure levels. If the system pressure drops, the pressure accumulator is emptied automatically, thereby providing additional pressure medium to the pressure medium supply. As a result, phase adjustment of the device is supported. Disadvantages of this embodiment include the situation where the pressure accumulator is emptied when the system pressure drops not on the basis of the adjustment process but on the basis of another external situation, for example by deceleration of the rotational speed. As such, 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 that 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 sent from the engine control unit to the device at high temperature and low rotational speed conditions, the pressure support of the pressure accumulator is less because the system pressure that was filled in the pressure accumulator was low. As a result, the adjustment process may not be carried out or the speed of adjustment may be significantly reduced. Therefore, even in this case, the pressure medium pump must be configured to meet the peak load which results in disadvantages.

It is an object of the present invention to provide a device 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 at high regulation speed conditions in each operating stage of the internal combustion engine. Another object is to allow the pressure medium pump to be set to an oversize (a configuration that matches the expected peak load), just as the use of a variable pressure medium pump is excluded.

The object is that, in accordance with the present invention, the displaceable member includes at least one second pressure surface that partially restricts the control space, and the displaceable member can be displaced against the force of the energy accumulator by applying pressure to the control space. And is achieved by preventing pressure medium flow from the storage space to the control space inside the pressure accumulator.

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

The displaceable member may 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. In addition, according to alternative embodiments, other forms of energy accumulators can also be used, such as for example a body made of elastomer and capable of reversible deformation, or a gas pocket filled with gas. By forming a pressure accumulator that includes a displaceable member that partially limits the pressure spaces that are isolated from each other within the pressure accumulator, the two pressure spaces can be controlled separately from each other, that is, filled and / or Can be emptied. There is no connection between the pressure spaces except for leaks. 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 between the storage space and the control space may be provided inside the pressure accumulator. The pressure medium supplied to the control space can reach the storage space via the pressure medium connection. In this case, however, it must be ensured that a pressure medium flow reverses from the storage space to the control space. This can be realized, for example, via a pressure medium channel provided inside the pressure accumulator's housing or pressure piston and inside which a check valve is arranged. In this case, the filling of the storage space and the control space can be made only by filling the control space. And if the pressure accumulator has to 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 and becomes pressureless. Overflow of the pressure medium, which can be made from the storage space to the 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. For this purpose, the control space is likewise filled with a pressure medium during the filling process of the storage space. This forces one force on the two pressure planes of the pressure piston to act on the two pressure planes, whereby a larger force is stored in the energy accumulator (the spring member is compressed more strongly). If the filled pressure accumulator is commanded by the engine control unit to support the phase adjustment process, the control space can 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 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 is emptied into the pressure medium supply. This causes all forces stored in the energy accumulator to act on the storage space through the first pressure surface. As a result, the pressure may rise by a factor of up to the following equation depending on the load acting on the energy accumulator at that point at the start of the support process.

)만큼 상승한다.In the above formula, 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 the energy accumulator, the pressure is at the start of the support process, as long as the spring has not yet reached its maximum compressed state.

Rise by)

The present invention is based on an apparatus for variably adjusting the control time of gas exchange valves of an internal combustion engine, comprising a drive member, an output member, one or more pressure chambers, a pressure medium supply device, and one or more pressure accumulators. In which case the pressure medium can be supplied to or discharged from the pressure chamber by the pressure medium supply device, and thus driven by supplying the pressure medium to the pressure chamber or withdrawing 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 are formed independently of each other to limit the two or more spaces that can be pressurized to the direction of displacement of the member. Here, one or more of the spaces (storage spaces) are connected to the pressure medium supply and can thus be emptied into the pressure medium supply during the phase adjustment process. In addition, one or more additional spaces (control spaces) are likewise supplied with a 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, into the tank against atmospheric pressure. The control space thus supports the filling process in such a way that the displaceable member is deflected more strongly than when no pressure medium supply to the control space is made.

By increasing the pressure provided from the pressure accumulator, the pressure accumulator can suppress the maximum consumption, whereby the pressure medium pump can be configured in accordance with the normal operation of the internal combustion engine. In short, there is no need for an oversized pressure medium pump to ensure absolute safe and quick adjustment of the phase position. In addition to this, the adjusting speed of the operating device is increased. According to an alternative embodiment, the size of the operating device can be set smaller while the adjustment speed is kept the same. By doing so, mass, mass moment of inertia and cost can be reduced.

According to an improved embodiment of the invention, the control space can optionally be 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 independent of the pressure source, for example, a servo consumer (eg, a power steering system). In this case, in the case of the pressure source of the servo-consuming device, the pressure accumulator can be completely filled even in the operating stage indicating low system pressure. The selective connection with the pressure source or tank is 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 contemplated, wherein one of the control means blocks or opens the connection from the pressure source to the control space, and the other control means blocks the connection from the control space to the tank. Or open. The control means may be an electromagnetically actuated hydraulic valve, for example a directional control valve (eg a switching or proportional valve), or a check valve which may be released. Such control means receive control signals from the engine control unit of the internal combustion engine, and the pressure accumulator is filled or emptied in accordance with these control signals. As a result, various support strategies can be realized. Similarly, the use of hydraulic actuation control means may be considered. In this case, the hydraulic actuating device of the control means can be connected to the pressure medium supply device. The control means can thus automatically switch to below the specified value when the pressure in the pressure medium supply drops. This significantly reduces the regulatory complexity.

According to an embodiment embodying the present invention, the control space can be emptied into the tank without a bypass path through the consuming device. The control space is then preferably emptied via a proportional or switching valve, usually against atmospheric pressure.

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

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

Thereby, no phase adjustment is carried out, but in the operating stages of the internal combustion engine where the system pressure drops nonetheless, the connection of the storage space to the pressure medium supply is prevented. As a result, the pressure and pressure medium volume in the storage space are maintained at high values.

In this regard, 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 only one directional control valve comprising one port for each storage line, control line, control space, storage space and tank. By doing so, the number of parts and the complexity of regulation during operation of the internal combustion engine are reduced. According to an alternative embodiment to this, the control means may comprise one or more first directional control valves arranged in the control line. The control means may also comprise a second directional control valve disposed in the storage line. In this connection the directional control valves can be formed for example as switching or proportional valves. According to an alternative embodiment to this the control means can also comprise a check valve which can be arranged and released in the storage line.

Preferably a check valve may be provided between the control space and the pressure source in the apparatus herein, which check valve blocks the flow of pressure medium from the control space towards the pressure source. Thereby the pressure medium volume located in the control space is enclosed until it is connected to the tank. By doing so, even if the system pressure drops, the displaceable member is kept in the deflected position, thereby avoiding emptying the storage space 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 pressure medium flow from the pressure medium supply device toward the storage space. By doing so, the pressure peak generated at the operating device is prevented from being transferred into the pressure accumulator. Thereby the pressure medium flowing back from the pressure chamber of the actuating device during the pressure peak is retained in the check valve, thereby increasing the hydraulic stiffness of the device of the present application, thereby increasing the speed of adjustment and transmitting torque from the crankshaft to the camshaft. Is improved.

In other words, the pressure support of the pressure accumulator can be activated through simple switching of one or more control means. In this regard, in the operating stages of the internal combustion engine where the phase position is kept constant, the pressure medium volume accumulates in the storage space is supplied. In this case, the pressure provided from the pressure accumulator corresponds to a factor which may correspond to a maximum of 1 + A ₂ / A ₁ and multiplied by the current system pressure, or may be the same factor as during the filling step, according to the respective embodiment. Corresponds to the product of the maximum system pressure. The complete factor (1 + A ₂ / A ₁ ) is always only when all the storage capacity of the energy accumulator is not yet 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 which at least partially limits the counter-pressure space, in which case the control medium or storage is provided if the pressure medium is supplied to the back pressure space. As in the case where the pressure medium is supplied to the space, the displaceable member is displaced in the opposite direction. As a result, the force applied to the displaceable member from the energy accumulator rises by the 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.

Pressure support of the pressure accumulator may be used during each phase adjustment process. For this purpose, whenever a phase adjustment is required, the control means (direction control valve and / or check valve which can be released) move to the position where the storage space is emptied. The pressure accumulator can be filled in the operating stage between phase adjustment requests. There is also another possibility of providing 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 for pressure support through the pressure accumulator. This measure extends the time that the pressure accumulator can be filled, thus increasing the performance of the pressure accumulator during pressure support. According to an alternative embodiment to this, the pressure support of the pressure accumulator can only be used as a "boost" function for a critical adjustment process that requires, for example, high volume flow or high adjustment speed. If at the engine control unit it is detected that the threshold adjustment process should be guided, 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 directed to or exiting the pressure chambers of the actuating device.

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

Preferably the maximum volume of the storage space corresponds to at least twice the volume required for phase adjustment from the maximum perceptual position to the maximum advance 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 can be introduced into the pressure medium line, which connects one of the operating ports of the control valve to one of the pressure chambers of the one side of the pressure medium lines. In addition to this embodiment, a second pressure accumulator may be provided which flows into the pressure medium line connecting the other actuation port of the control valve to the pressure chambers of the other group.

Further features of the invention are presented in the following detailed description and in the drawings, in which embodiments of the invention are schematically illustrated.
1 is a schematic diagram showing only an internal combustion engine very schematically.
2A is a longitudinal cross-sectional view of the actuating device.
2b is a cross-sectional view of the actuating device.
3 shows a first embodiment of the device of the present application.
4-12 are diagrams of further embodiments of the device herein.

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

3 shows a first embodiment of a device 10 according to the invention with operating devices 10a, b, c, a pressure medium supply device 37, and a pressure accumulator 43. 2a and 2b show the actuating devices 10a, b and c respectively in longitudinal and cross sectional views. The actuating devices 10a, b, c comprise a drive member formed as the outer rotor 22 and an output member formed as the inner rotor 23. The outer rotor 22 comprises a housing 22a and two side covers 24, 25 arranged on the axial side of the housing 22a. The inner rotor 23 is embodied in the form of an impeller and comprises a hub member 26 which is substantially cylindrical in shape. From the outer cylindrical circumferential surface of the hub member five vanes 27 are shown in the embodiment shown. It extends outward in the radial direction. The vanes 27 are formed independently toward the inner rotor 23 and are disposed in the vane groove 28 formed in the hub member 26. The vanes 27 are energized outwardly in the radial direction by vane springs 27a respectively disposed between the groove bottoms of the vane grooves 28 and the vanes 27.

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

A chain wheel 21 is arranged on the outer jacket surface of the circumferential wall 29, by which the chain wheel can transmit torque from the crankshaft 2 to the outer rotor 22 via a chain drive not shown. have.

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

Inside the operating devices 10a, b, c, a hollow space 33 is formed between each of the two circumferentially neighboring projections 30. Each of the hollow spaces 33 is constrained by such limiting wall portions 34, which are opposite each other and extend substantially radially as limiting wall portions 34 of neighboring protrusions 30 in the circumferential direction, It is constrained by the side covers 24, 25 in the axial direction, by the hub member 26 facing inward in the radial direction, and by the circumferential wall 29 facing outward in the radial direction. A vane 27 protrudes into each of the hollow spaces 33, and this vane 27 is formed in such a manner that the vanes come into contact with the circumferential wall 29 as well as the side covers 24 and 25. . Each vane 27 thus divides the corresponding hollow space 33 into two interacting pressure chambers 35, 36.

The inner rotor 23 can be rotated relative to the outer rotor 22 in a defined angle range. The angular range is limited by the vane 27 in contact with the corresponding limiting wall portion 34 (advance stop 34a) of the hollow spaces 33 in one direction of rotation of the inner rotor 23. Similarly the angular range is limited in the other direction of rotation by the vane 27 being in contact with the other limiting wall portions 34 of the hollow spaces 33 serving as the crust stop 34b.

By supplying pressure to the pressure chambers 35 and 36 of one group and depressurizing the pressure chambers of the other group, the phase position of the outer rotor 22 relative to the inner rotor 23 can be varied. When pressure is supplied to both groups of pressure chambers 35 and 36, the phase positions of the two rotors 22 and 23 can be kept constant with each other. According to an alternative embodiment to this, the pressure medium may not be supplied to any of the pressure chambers 35, 36 during the phase phase constant phase. As a hydraulic pressure medium, the lubricating oil of the internal combustion engine 1 is used normally.

The pressure medium supply device 37 shown in FIG. 3 is provided for supplying pressure medium to the pressure chambers 35 and 36 or for discharging pressure medium from the pressure chambers. The pressure medium supply device 37 comprises 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, connects the first pressure chamber 35 and the first operating port A, and the second pressure chamber 36. ) And the second operation port (B), and connects the tank 39 and the tank port (T). The pressure medium is thereby able to reach the supply port P of the control valve 40 from the pressure medium pump 38 via 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. In the second position of the control valve 40 neither of the pressure chambers 35, 36 is connected to the tank 39 and the supply port P. In the third position of the control valve 40 the supply port P is connected to the second pressure chamber 36, while the first pressure chamber 35 is connected to the tank 39.

On the camshafts 6, 7 during the operation of the internal combustion engine 1, alternating torques caused by the rolling contact of the cams 8 to the cam followers are applied. The force of the valve spring then acts on the camshafts 6, 7 in a manner that is braked until the gas exchange valve is fully open. Following this, the camshafts 6 and 7 are accelerated by the force of the valve spring. The result is a pressure peak inside the actuators 10a, b, c which causes the pressure chambers 35 and 36 connected to the supply port P to be emptied with respect to the pressure medium pump 38. This will drastically slow down the adjustment speed. 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, which may be made to the pressure medium pump 38 through the control valve 40 from the pressure chambers 35, 36. The pressure peak is reserved at the check valve 42a, whereby undesirably emptying the pressure chambers 35 and 36 is effectively prevented, thereby increasing the stability and speed of adjustment of torque transmission.

The speed of adjustment of the actuating device 10a, b, c depends on the pressure medium volume flow provided by the pressure medium pump 38 or the pressure provided by the pump. The pressure provided or the pressure medium volume flow provided is itself dependent on a number of factors, such as the speed of the internal combustion engine 1 and the pressure medium temperature. The pressure medium pump 38 must be configured accordingly in order to ensure the required speed of regulation even in the worst conditions such as high pressure medium temperatures and / or low rotational speeds. Thereby a pressure medium pump 38 is used, which is configured to meet the maximum requirements of the actuating devices 10a, b, c, and thus is set to an oversize during most of the operating stages of the internal combustion engine 1. In addition, according to an alternative embodiment, an adjustable pressure medium pump 38 may also be used which provides the 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 this disadvantage, the device 10 is provided with a pressure accumulator 43. The pressure accumulator 43 includes a displaceable member that is formed as a pressure piston 45, which can be displaced against the force of the energy accumulator inside the pressure tank 44. In the illustrated embodiment the energy accumulator is implemented as a spring member 46. However, other types of energy accumulators are also conceivable, such as, for example, suitably formed elastomeric bodies or gas filled gas pockets.

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. In this case, 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 and 50 inside the pressure accumulator 43. According to the embodiment shown, 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 the storage line 51, and the storage line 51 flows into the pressure medium supply device at the rear of the check valve 42a when viewed in the flow direction. do. The control space 50 may optionally be connected to the tank 39, or may be connected 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. However, it is likewise conceivable to use another pressure source such as, for example, the pressure medium pump 38 of the servo consumer of the power steering system. In this case, the pressure medium discharged from the control space 50 is not directed to the tank 39 of the lubricating oil circuit of the internal combustion engine 1, but to the corresponding tank 39 of the servo consumer.

In order to control the pressure medium flow to or from the control space 50, control means 60 are provided in the form of a first directional control valve 53. 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 device 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. Is 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 is connected to the discharge port T ₁ , while the pressure port P _{1 is} connected to the other ports T ₁ , A _1. Is not connected to any of the ports.

In addition to this, an additional check valve 42b is provided, which is arranged in the control line 52 to prevent the pressure medium from flowing back from the control space 50 to the pressure medium supply device 37. If no adjustment request from the engine control unit is transmitted to the apparatus 10 of the present application during operation of the internal combustion engine 1, the control valve 40 is located in the second (middle) position and the first directional control valve 53. ) Is located in the first position. As a result, no pressure medium flows into or out of the actuating device 10a. At the same time, the pressure medium not only reaches the storage space 49 via the storage line 51, but also reaches the control space 50 via the control line 52. The pressure medium introduced into the storage space 49 or the control space 50 acts on the pressure surface 47 or the pressure surface 48, whereby the pressure piston 45 stops against the force of the spring member 46. Displaced in the direction of the portions 54, thereby increasing the volume of the control space 50 and the storage space 49. If the pressure drops in the pressure medium supply device 37, the pressure in the storage space 49 also drops to the same degree. Based on the pressure drop between the control space 50 and the pressure medium supply device 37, the check valve 42b in the control line 52 is closed, thereby from the pressure drop in the control space 50 and from the control space. Discharge of pressure medium is prevented. As a result, the volume of the control space 50 and the storage space 49 remains constant despite the pressure drop in the pressure medium supply device 37. In this case, the following equation applies to the path x in which the pressure piston 45 is deflected from its stop position.

In the above formula 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 maximum system pressure occurring during the filling step, D corresponds to the spring constant of the spring member 46. The maximum displacement path is then limited by the stops 54. Here, the stop position means a 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 chambers 35, 36 from the pressure medium pump 38, whereby phase adjustment is caused by the operating devices 10a, b, c. If the volume flow discharged from the pressure medium pump 38 is too small to ensure adjustment, or must reach a higher adjustment speed, 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. Thereby the pressure medium present under pressure within the control space 50 is connected to 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 of the control space 50 is quickly emptied in such a way that the pressure piston 45 is supported against the storage space 49 only through the first pressure surface 47, the total force of the spring member 46 is stored. It only acts on space 49. As a result, as long as the pressure piston 45 is not yet fully deflected, that is, not in contact with the stops 54, the pressure p present in the storage space 49 at the beginning of the emptying process is The formula is applied.

In the pressure medium line 41, since the check valve 42a is disposed in front of the storage line 51 in the flow direction, the total pressure p and the total volume of the storage space 49 are actuated 10a. ), And is not discharged into the oil passage of the internal combustion engine 1. Thus not only the current system pressure or the maximum filling pressure is provided, as in the case of use with a conventional pressure accumulator, but also a pressure raised by a factor of 1 + A ₂ / A ₁ . This allows the pressure medium supply device 37 to receive pressure support by adjusting the second control position in the first directional control valve 53. In addition, the adjusting speed of the actuating device 10a can be significantly increased if the size settings are the same, or if the adjusting speed is the same, the actuating device 10a can be implemented smaller, which is a pressure that is set or adjusted to an oversize. Without taking the disadvantages of the media pump 38.

Similarly conceivable is an embodiment in which no check valve 42b is placed in the control line 52. In the operating stage of the internal combustion engine 1 in which the phase position is kept constant, the pressure accumulator 43 is filled similarly to the embodiment described above. When the system pressure drops, the pressure medium is discharged from the control space 50 as well as the storage space 49. This causes a pressure drop in the two spaces 49 and 50, which displaces the pressure piston 45 in the direction of the stop position of the pressure piston. This reduces the pressure that can be provided in the storage space 49 in accordance with the present embodiment, as well as the volume of pressure medium that can be provided for phase adjustment. Nevertheless, when the first directional control valve 53 is switched to the second switching position, the pressure rise is started in the storage space 49. In this case, the following equation applies to 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 when pressure support is initiated. In this connection, one may consider the use of this embodiment in an internal combustion engine 1 in which the maximum required system pressure only slightly exceeds the capacity of the pressure medium pump 38. In this case, it is not necessary to arrange the check valve 42b in the control line 52, thereby reducing 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.

Likewise, in addition to the first actuating device 10a, one or more further actuating devices 10b, 10c may be controlled by the pressure medium supply device 37 via the additional pressure medium lines 41 and the additional control valves 40. You can also think about it. The further actuating device 10b can likewise be supported by the pressure accumulator 43. For this purpose a branch to the actuating device 10b is located behind the check valve 42a in the flow direction. If the pressure accumulator 43 must support only the first actuating device 10a, the branch directed to the further actuating device 10c must be arranged 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 towards the tank 39.

It is likewise conceivable that the check valve 42a is arranged at the rear of the branch towards the storage line 51 in the flow direction (FIG. 4). In this case a pressure peak is reserved between the actuating devices 10a and b and the branch to the storage line 51. As a result, the pressure peak does not reach the pressure accumulator 43, whereby a more stable torque transmission through the actuators 10a, b is achieved. It is likewise conceivable to insert the check valves 42a in the pressure medium line 41, respectively, in front of and behind the branch towards the storage line 51 in the flow direction (FIG. 5). In this case, not only stable torque transmission is achieved through the operating devices 10a and b, but also the pressure medium volume or pressure in the storage space 49 is prevented from being discharged to the oil passage of the internal combustion engine 1.

A further embodiment of the device 10 according to the invention is shown in FIG. 6. Unlike the embodiment shown in FIG. 3, in this embodiment an additional check valve 42c is arranged in the storage line 51. This check valve 42c prevents the pressure medium flow from the pressure medium supply device 37 into the storage space 49, whereby the pressure peaks generated within the actuators 10a, b, c are pressure accumulators. It does not advance to the storage space 49 of 43, and is reserved by the check valve 42c. The hydraulic stiffness of the device 10 thereby rises similar to the embodiment according to FIG. 5. A connection line 55 is provided to fill the storage space 49 of the pressure accumulator 43, which is connected between the pressure medium supply device 37 and the first directional control valve 53 on one side. Flows into the line 52 and into the storage line 51 between the check valve 42c and the storage space 49 on the other side. In this connection in the connection line 55 an additional check valve which prevents the pressure medium exiting the storage space 49 from flowing into the pressure medium supply device 37 between the pressure medium pump 38 and the check valve 42a. 42d may be disposed. According to a slightly modified example of this embodiment, between the inlet points of the pressure accumulator 43, all the pressure medium lines 41 and / or the check valve 42b in which the check valve 42a is disposed will also be omitted. Can be.

7 to 11 show further embodiments of the invention for the device 10, respectively. In such embodiments, control means 60 are provided on the storage line 51 as well as the control line 52. These 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, in accordance with the illustrated embodiment, to the pressure medium supply device 37 via each of the control line 52 or the storage line 51. do. The control space port A ₁ is connected to the control space 50, 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, one side flows into the control line 52 between the direction control valve 56 and the control space 50, and the other side flows into the storage line 51 between the direction control valve 56 and the storage space 49. There is provided a connection line 55. In this connection line 55 a check valve 42d is arranged which prevents the pressure medium flow 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 , 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 , while the pressure Port P ₁ is not connected to any of the other ports A ₁ , B ₁ , T ₁ , 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 reaches the control space 50 from the pressure medium supply device 37 through the control line 52 and the directional control valve 56. At the same time the storage space 49 is likewise filled via the connection line 55. 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 in the pressure medium supply device 37 decreases, the pressure in the control space 50 likewise decreases. However, the storage space 49 maintains a high pressure state because the storage space is isolated from the pressure medium supply device 37 by the direction control valve 56 on one side and the check valve 42d on the other side. to be. As a result, the pressure accumulator 43 maintains its filled state. If the directional control valve 56 is switched to the second control state, the control space 50 is emptied into the tank 39 on one side and the storage space 49 is emptied into the pressure medium supply device 37 on the other side. . This process proceeds similarly to the first embodiment (Fig. 3).

FIG. 8 shows a further embodiment according to the invention which differs from the above mentioned embodiments only in the arrangement of the check valve 42a. In this connection the check valve 42a is arranged similarly to the embodiment according to FIG. 4. Also contemplated is an embodiment similar to FIG. 5 comprising two check valves 42a disposed respectively in front of and behind the storage line 51 in the flow direction.

9 to 11 show further devices 10 according to the invention substantially the same as the devices according to FIGS. 7 and 8, respectively. In contrast to the device according to FIGS. 7 and 8, the devices 10 shown in FIGS. 9 to 11 have only one control means 60 (only one directional control valve according to the embodiment shown). Instead, it is provided with two control means 60. The first control means 60 thus 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, the control space 50. And control the connection between the tank 39.

According to the embodiment shown in FIG. 9, the first control means 60 is formed as a check valve 42e which can be released, which check valve is stored from the pressure medium supply device 37 in the first control position. Allow pressure medium flow to 49, but impede pressure medium flow in the opposite direction. In the second control position the pressure medium flow 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.

FIG. 10 shows an alternative embodiment, unlike the embodiment according to FIG. 9, wherein the check valve 42e which can be released is the second directional control valve 57, and in some embodiments a 2/2 directional control valve. It is shown. The second directional control valve 57 in the first control position does not allow pressure medium flow between the pressure medium supply device 37 and the storage space 49. In the second control position the pressure medium can flow in both directions.

FIG. 11 shows that, unlike the embodiment according to FIG. 10, only the pressure medium flow from the pressure medium supply device 37 toward the control space 50 in the first control position is permitted while the opposite pressure medium flow is The embodiment in which the first directional control valve 53 is modified in such a way as to be prevented by the one-way control valve 53 is shown.

FIG. 12 shows a further aspect of the invention described according to the embodiment shown in FIG. 6. It should be clearly noted that the above point can be used in all the above-mentioned embodiments here. 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. Is different from the device 10 shown in FIG. Rather, the spring space is formed as a back pressure space 58 which can be filled with a pressure medium. The first directional control valve 53 has an additional back pressure port G which is connected to the back pressure space 58 according to this 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 discharge 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 in the first control position, no change occurs compared to the embodiment according to FIG. 6. However, in the second control position further pressure medium is 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 illustrated embodiments, the pressure accumulator 43 is introduced into the pressure medium line 41 connecting the control valve (s) 40 and the pressure medium pump 38. Similarly, an embodiment is conceivable in which the pressure accumulator (s) 43 are introduced into a pressure medium line 41 connecting the actuating devices 10a, b and the control valve (s) 40.

In addition to using the pressure accumulator 43 in applications for variable control of the control time in the internal combustion engine 1, this pressure accumulator 43 is used in another vehicle field, for example in a switchable cam follower, or in an automated manner. 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: external rotor
22a: housing
23: inner rotor
24: side cover
25: side cover
26: hub member
27: vane
27a: vane spring
28: vane groove
29: circumferential wall
30: protrusion
32: fixed member
33: hollow space
34: limited wall
34a: advance stop
34b: crust stop
35: first pressure chamber
36: second pressure chamber
37: pressure medium supply device
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 that can be released
43: pressure accumulator
44: pressure tank
45: pressure piston
46: spring member
46a: air outlet
47: first pressure surface
48: second pressure surface
49: storage space
50: control space
51: storage line
52: control line
53: first directional control valve
54: stop
55: connection line
56: directional control valve
57: second direction control valve
58: back pressure space
59: third pressure surface
60 control means
A: first operating port
B: second operating port
P: supply port
T: discharge port
P ₁ : Pressure port
T ₁ : discharge port
A ₁ : Control Space Port
B ₁ : Storage Port
V ₁ : storage port
G: back pressure port

Claims (18)

It is an apparatus 10 for variably adjusting the control time of the gas exchange valves 9a and b of the internal combustion engine 1,
A drive member 22, an output member 23, one or more pressure chambers 35, 36, a pressure medium supply device 37, and one or more pressure accumulators 43,
The pressure medium supply device 37 can supply or discharge pressure medium to or from one or more pressure chambers 35, 36, and
The phase position of the output member 23 relative to the drive member 22 can be varied by supplying pressure medium to the pressure chambers 35 and 36 or withdrawing pressure medium from the pressure chamber,
The pressure accumulator 43 comprises a displaceable member 45 having a first pressure surface 47 which partially restricts 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 is adapted to an apparatus for variably adjusting the control time of the gas exchange valve of the internal combustion engine, which can be displaced against the force of the energy accumulator 46. In
The displaceable member 45 comprises at least one second pressure surface 48 which partially constrains 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,
A device 10 for variably adjusting the control time of the gas exchange valve of the internal combustion engine, characterized in that the pressure medium flow from the storage space 49 to the control space 50 is inhibited inside the pressure accumulator 43. ). Control time of the gas exchange valve of the internal combustion engine 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 operation of the internal combustion engine (1). Apparatus 10 for variable adjustment. 10. Apparatus 10 for varying the control time of a gas exchange valve of an internal combustion engine, according to claim 1, characterized in that the control space 50 can be emptied into the tank 39 without a bypass path through the consuming device. ). 3. Control means 60 are provided, characterized in that the control space 50 can be selectively connected to the tank 39 or the pressure source 38 by means of the control means 60. And apparatus 10 for variably adjusting the control time of the gas exchange valve of the internal combustion engine. The method of claim 2,
Interrupting the pressure medium flow from the storage space 49 to the pressure medium supply device 37 in the first state and allowing the pressure medium flow to the storage space 49 and the control space 50,
In an additional state allowing a pressure medium flow from the storage space 49 to the pressure medium supply device 37 and forming a connection between the control space 50 and the tank 39 without a bypass path through the consuming device.
Apparatus (10) for varying the control time of the gas exchange valve of the internal combustion engine, characterized in that control means (60) are provided. 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) and the control space (50). Apparatus (10) for varying the control time of the gas exchange valve of the internal combustion engine, characterized in that the. 7. The control means (60) according to claim 6, wherein the control means (60) comprises one port (A ₁ ) for the storage line (51), control line (52), control space (50), storage space (49), and tank (39). Apparatus for varying the control time of a gas exchange valve of an internal combustion engine, characterized in that it is formed as only one directional control valve 56 comprising B ₁ , P ₁ , T ₁ , V ₁ . ). 7. The variable control time 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). Device 10. 9. The internal combustion engine of claim 8, characterized in that the control means 60 also comprise a second direction control valve 57 or a check valve 42e which can be released, which is arranged in the storage line 51. Apparatus 10 for variably adjusting the control time of the gas exchange valve. 9. The control means 60 according to claim 8, characterized in that the control means 60 also comprises a release check valve 42e which is arranged in the storage line 51. Device 10. 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). An apparatus (10) for variably adjusting the control time of a gas exchange valve of an internal combustion engine, characterized in that a check valve (42d) blocks the pressure medium flow from the storage space (49) to the control space (50). 2. A check valve (42b) according to claim 1, characterized in that a check valve (42b) is provided between the control space (50) and the pressure source (38) to block the flow of pressure medium from the control space (50) to the pressure source (38). And apparatus 10 for variably adjusting the control time of the gas exchange valve of the internal combustion engine. A check valve (42c) is provided between the storage space (49) and the pressure medium supply device (37) according to claim 1, wherein a check valve (42c) for blocking a pressure medium flow directed from the pressure medium supply device (37) toward the storage space (49) is provided. Apparatus (10) for varying the control time of a gas exchange valve of an internal combustion engine, characterized in that it is provided in. The method of 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, Apparatus (10) for varying the control time of the gas exchange valve of the internal combustion engine. 2. The displaceable member 45 comprises a third pressure surface 59 at least partially restricting the back pressure space 58, wherein the displaceable member 45 is provided when a pressure medium is supplied to the back pressure space 58. 45 is a device for variably adjusting the control time of a gas exchange valve of an internal combustion engine, characterized in that it is displaced in a direction opposite to when a pressure medium is supplied to the control space 50 or the storage space 49 ( 10). 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 units 10a and b is the second pressure according to claim 2 or 5. An apparatus (10) for varying the control time of a gas exchange valve of an internal combustion engine, characterized in that it is greater than the ratio between the area of the face (48) and the area of the first pressure face (47). 2. The device according to claim 1, wherein the storage space 49 and the control space 50 are not connected to each other inside the pressure accumulator 43. (10). 5. Apparatus (10) according to claim 4, characterized in that the control means (60) are formed as directional control valves (53).

Images