EP2220345B1 - Device for variably adjusting control times of gas exchange valves of an internal combustion engine - Google Patents

Abstract

A device for variably adjusting control times of gas exchange valves of an internal combustion engine. The device has a drive element, an output element, a rotation angle limiting device and a control valve and counter-working pressure chambers are also provided. Phase adjustment between the output and drive element is initiated by applying pressure to one pressure chamber while discharging the other pressure chamber. The rotation angle limiting device can be locked or unlocked to prevent or allow phasing. The control valve has a valve housing and a control piston. An inflow connection, an outflow connection, a control connection and two working connections are embodied on the valve housing.

Description

Field of the invention

The invention relates to a device for variably setting the timing of gas exchange valves of an internal combustion engine with a drive element, an output element, a rotation angle limiting device and a control valve, wherein at least two mutually acting pressure chambers are provided, wherein by pressurizing one of the pressure chambers while emptying the other pressure chamber, a phase adjustment between the output element and the drive element, wherein the rotation angle limiting device prevents a change in the phase position in a locked state, wherein the rotation angle limiting device in a unlocked state allows a change in the phase position, wherein the rotation angle limiting device are transferred by the pressure medium from the locked to the unlocked state can, wherein the control valve has a valve housing and a control piston, wherein at the inlet valve port is connected to a pressure source, the drain port to a tank, the control port to the rotational angle limiting device and the working ports to each one of the pressure chambers and the control valve is arranged in a central receptacle of the output element.

Background of the invention

In modern internal combustion engines devices for variable adjustment of the timing of gas exchange valves are used to the phase relation between the crankshaft and the camshaft in a defined Winkelbeon between the crankshaft and the camshaft in a defined angular range, between a maximum early and a maximum late position to make variable. For this purpose, the device is integrated into a drive train, via which torque is transmitted from the crankshaft to the camshaft. This drive train can be realized for example as a belt, chain or gear drive.

The device comprises at least two rotors rotatable relative to one another, one rotor being in driving connection with the crankshaft and the other rotor being connected in a rotationally fixed manner to the camshaft. The device comprises at least one pressure chamber, which is subdivided by means of a movable element into two counteracting pressure chambers. The movable element is in operative connection with at least one of the rotors. By supplying pressure medium to the pressure chambers or pressure medium discharge from the pressure chambers, the movable element is displaced within the pressure chamber, whereby a targeted rotation of the rotors to each other and thus the camshaft is caused to the crankshaft.

The pressure medium inflow to, or the pressure drain from the pressure chambers is controlled by means of a control unit, usually a hydraulic directional control valve (control valve). The control unit, in turn, is controlled by means of a regulator which, with the aid of sensors, determines the actual and desired position of the camshaft relative to the crankshaft (phase position) and compares them with one another. If a difference is detected between the two positions, a signal is sent to the control unit which adapts the pressure medium flows to the pressure chambers to this signal.

In order to ensure the function of the device, the pressure in the pressure medium circuit of the internal combustion engine must exceed a certain value. Since the pressure medium is usually provided by the oil pump of the internal combustion engine and the pressure provided thus increases synchronously with the speed of the internal combustion engine, below a certain speed of the oil pressure is still too low to change the phase of the rotors targeted or to keep. This may for example be the case during the starting phase of the internal combustion engine or during idling phases.

During these phases, the device would make uncontrolled oscillations, resulting in increased noise emissions, increased wear, choppy running, and increased raw engine emissions. In order to prevent this, mechanical locking devices can be provided which, during the critical operating phases of the internal combustion engine, couple the two rotors in a torque-proof manner with one another, wherein this coupling can be canceled by pressurizing the locking device. In this case, the locking position may be provided in one of the end positions (maximum early position and the maximum late position) or between the end positions.

Such a device is for example from the US 6,684,835 B2 known. In this embodiment, the device is designed in vane-type construction, wherein an outer rotor is rotatably mounted on an inner rotor designed as an impeller. Furthermore, two rotational angle limiting devices are provided, wherein a first rotational angle limiting device in the locked state allows an adjustment of the inner rotor to the outer rotor in an interval between a maximum late position and a defined center position (locking position). The second rotation angle limiting device allows in the locked state, a rotation of the inner rotor to the outer rotor in an interval between the center position and the maximum early position. If both rotational angle limits are in the locked state, the phase angle of the inner rotor to the outer rotor is limited to the middle position.

Each of the rotational angle limiting devices consists of a spring-loaded locking pin, which is arranged in a receptacle of the outer rotor. Each locking pin is acted upon by a spring in the direction of the inner rotor with a force. On the inner rotor a gate is formed, which faces the locking pins in certain operating positions of the devices. In these operating positions, the pins can engage in the backdrop. In this case, the respective rotation angle limiting device from de to locked state. Each of the rotation angle limiting devices can be transferred by pressurizing the gate from the locked to the unlocked state. In this case, the pressure medium urges the locking pins back into their receptacle, whereby the mechanical coupling of the inner rotor to the outer rotor is canceled.

The pressure medium is applied to the pressure chambers and the gate by means of a control valve, wherein on the control valve, inter alia, two working ports which communicate with the pressure chambers, and a control port, which communicates with the locking groove, are formed. Other such control valves are from the US 6,779,500 B2 known. These control valves consist essentially of a conventional 4/3-way proportional valve, which directs the pressure medium flows to and from the pressure chambers, and a 2/2-way valve, which regulates the pressure medium flows to and from the rotation angle limiting devices, wherein the part valves are arranged in series. In this case, the two part valves on a common control piston and a common valve housing.

A disadvantage of these embodiments, the high space requirement of the control valve, especially in the axial direction of the valve housing. Furthermore, the large number of control structures that must be formed on the control piston disadvantageous. This leads to increased costs and higher space requirements. Another disadvantage is that these control valves are not suitable for use as a central valve, which is arranged in a central receptacle of the inner rotor. On the one hand, the control valves on two inlet connections, which must be supplied via the inner rotor of the device pressure medium. This increases the complexity and the susceptibility of the device to errors. Furthermore, the device is to be made wide in the axial direction, so that all five ports of the valve are covered by the receptacle of the inner rotor. This leads to increased costs in the manufacture of the device. Furthermore, their space requirements and their weight is increased.

Object of the invention

The invention has for its object a device for variable adjustment of the timing of gas exchange valves of an internal combustion engine with a control valve to represent, with as simple and thus cost-effective design of the control valve to be achieved. In addition, the space requirement of the control valve should be minimized.

According to the invention the object is achieved in that the inlet port is arranged in the axial direction outside of the output element and the drive element and the working ports and the control port, depending on the position of the control piston within the valve housing, optionally connected to the inlet port or can be separated from this. In a concretization of the invention it is provided that the working ports, the inlet port and the control port are formed as radial openings in the valve housing.

The connections can be axially offset from one another and arranged in the order inlet connection, working connection, drain connection, working connection, control connection or inlet connection, control connection, drain connection, working connection, working connection.

In a further development of the invention, provision is made for a further outlet connection to be formed as an axial connection on the valve housing. In addition, it can be provided to form the control piston hollow and that the interior of the control piston communicates in each position of the control piston relative to the valve housing with the inlet connection.

In a concretization of the invention, it is proposed that the interior of the control piston can be connected to each of the working ports and the control port by suitable positioning of the control piston within the valve housing.

It can be provided that the control valve can assume a first control position, in which the first working connection exclusively with the outflow connection, the second working connection exclusively with the inflow connection and the control port only communicates with the axial drain port.

In a development of the invention, it is proposed that the control valve can assume a second control position, in which the first working connection communicates exclusively with the outflow connection and the second working connection and the control connection exclusively with the inflow connection. It can be provided that the control valve can assume a third control position, in which the control connection communicates exclusively with the inlet connection, while the working connections communicate neither with the inlet connection nor with the one of the outlet connections.

Furthermore, it is proposed that the control valve can assume a fourth control position in which the second working connection communicates exclusively with the outflow connection and the first working connection and the control connection exclusively with the inflow connection.

The device comprises an adjusting device, which is designed as a hydraulic actuator, and a hydraulic system, which supplies the adjusting device with pressure medium. The adjusting device may be formed, for example, as in the prior art in vane type or in axial piston design. In the latter type, a pressure piston, the two pressure chambers separated from each other by pressure medium applied in the axial direction. The movement of the pressure piston over two pairs of helical gears causes a relative phase rotation between the output element and the drive element. Furthermore, mechanical means (rotation angle limiting device) are provided in order to mechanically couple the output element to the drive element in a specific phase position. The coupling may for example be such that the possible phase angles are limited to an angular range or that a rotationally fixed coupling between the output element and the drive element can be produced in a defined phase position. The rotation angle limiting device (s) may assume a locked state (coupling established) and an unlocked state (no coupling). The transition from the locked to the unlocked state takes place by pressurizing the rotational angle limiting device (s).

By pressurizing a pressure chamber or a group of pressure chambers with simultaneous emptying of the other pressure chamber or pressure chambers, a phase adjustment of the inner rotor 23 relative to the outer rotor 22, when the rotation angle limiting device (s) are present in the unlocked state. In the locked state of the rotation angle limiting device (s), the phase adjustment takes place only in the area permitted by the rotation angle limiting device (s).

The hydraulic system has a control valve with a valve housing and a control piston. The valve housing can be made substantially hollow cylindrical. In this case, the connections may be formed as openings in the cylindrical lateral surface. Within the valve housing, a control piston occupy several positions relative to this, thereby several control positions can be realized. It can be provided that the control piston can be moved by means of an adjusting unit in the axial direction of the valve housing relative to this. The actuator may be, for example, electromagnetic or hydraulic nature. In each control position results in a defined connection of different connections. The connections formed as openings on the lateral surface of the valve housing are arranged offset to one another. Thus, the control piston and the valve housing may be formed substantially rotationally symmetrical, whereby the production can be considerably simplified. The control piston has a plurality of control structures. In this case, a first control chamber is provided, which communicates on the one hand in each position of the control piston with the inlet connection and on the other hand with one of the working ports and the control port (or the other working port) is connectable. In this case, positions of the control piston can be provided, in which the first control chamber communicates exclusively with the working connection or the control connection (or other working connection). Furthermore, positions may be provided in which the first control room communicates with both terminals. By controlling the working connection and the control port (or the other working port) by means of a control chamber, the complexity of the control piston can be reduced. Fewer control elements are required, which eliminates the need for their elaborate processing and thus the production costs can be reduced. Furthermore, the reduction in the number of necessary controls brings a reduction of the axial space with it, so that a use as a central valve is conceivable. By a suitable arrangement of the cooperating with the first control chamber control structures on the valve housing, the desired control logic of the control valve can be defined.

The control chambers can be formed, for example, as an annular groove on the outer circumferential surface of the control piston. Equally conceivable would be the formation of Teilringnuten.

The connection between the first control chamber and the inlet connection can take place via the interior of the hollow control piston. Pressure medium, which enters via the inlet connection, can pass through piston openings into the interior of the control piston. Furthermore, further piston openings can be provided, which connect the first and / or the second control chamber to the interior of the piston.

By arranging the connections in the sequence inlet connection, working connection (or control connection), drain connection, working connection, control connection (or working connection), the control valve can be provided for central valve applications. Due to the sequence of connections, the pressure medium supply of the control valve can be arranged outside of the adjusting device. In this case, the control valve protrudes in the axial direction out of the inner rotor, wherein the inlet connection is outside the inner rotor. Thus, the width of the inner rotor only has to correspond to the maximum distance between the working ports, the control port and the drain port. The inner rotor and thus the adjusting device can thus be made narrower. Furthermore, no pressure medium lines within the inner rotor are necessary to direct the pressure medium to the inlet or to the inlet ports, whereby the architecture of the actuator simplified and thus the manufacturing cost can be reduced. The central valve solution leads to a stiffer hydraulic clamping of the wing in the pressure chamber.

Furthermore, it can be provided that the control valve can assume a first control position, in which the first working connection communicates exclusively with the tank, the second working connection exclusively with the inflow connection and the control connection exclusively with the tank. In addition, a second control position may be provided, in which the first working connection communicates exclusively with the tank and the second working connection and the control connection exclusively with the inflow connection. In addition, a third control position may be provided, in which the control port only communicates with the inflow port, while the working ports do not communicate with either the inflow port or the one of the outflow ports. In addition, a fourth control position may be provided, in which the second working connection communicates exclusively with the tank and the first working connection and the control connection exclusively with the inflow connection.

Thus, the control port and thus the rotational angle limiting device (s) are connected to the tank during the start of the internal combustion engine, in which the control valve assumes the first control position. Thus, the coupling between the inner rotor and outer rotor is ensured during the start. The control positions two to four allow a phase adjustment in the direction of early or late control times or a hydraulic fixation of the phase position.

Brief description of the drawings

Figur 1

nur sehr schematisch eine Brennkraftmaschine,

Figur 2a

eine Draufsicht auf eine erfindungsgemäße Vorrichtung zur Ver- änderung der Steuerzeiten von Gaswechselventilen einer Brenn- kraftmaschine mit einem Hydraulikkreislauf, wobei das Steuerven- til nur schematisch dargestellt ist,

Figur 2b

einen Längsschnitt durch die Vorrichtung aus Figur 2a entlang der Linie II B-II B, mit dem Steuerventil,

Figur 3a-3d

jeweils einen Längsschnitt durch das Steuerventil aus Figur 2b in dessen verschiedenen Steuerstellungen.

Further features of the invention will become apparent from the following description and from the drawings in which an embodiment of the invention is shown in simplified form. Show it:

FIG. 1

only very schematically an internal combustion engine,

FIG. 2a

2 is a plan view of a device according to the invention for changing the timing of gas exchange valves of an internal combustion engine with a hydraulic circuit, wherein the control valve is shown only schematically,

FIG. 2b

a longitudinal section through the device FIG. 2a along the line II B-II B, with the control valve,

Figure 3a-3d

in each case a longitudinal section through the control valve FIG. 2b in its different control positions.

Detailed description of the drawings

In FIG. 1 an internal combustion engine 1 is sketched, wherein a seated on a crankshaft 2 piston 3 is indicated in a cylinder 4. The crankshaft 2 is in the illustrated embodiment via a respective traction drive 5 with an intake camshaft 6 and exhaust camshaft 7 in combination, with a first and a second device 10 for a relative rotation between the crankshaft 2 and the camshafts 6, 7 can provide. 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. Likewise, it may be provided to equip only one of the camshafts 6, 7 with a device 10, or to provide only one camshaft 6, 7, which is provided with a device 10.

The FIGS. 2a and 2 B show an embodiment of a device 10 according to the invention in a plan view or in longitudinal section.

The device 10 has an adjusting device 11 and a hydraulic system 12. The adjusting device 11 has a drive element (outer rotor 22), a drive element rotatably connected to the camshaft 6, 7 (inner rotor 23) and two side covers 24, 25. The inner rotor 23 is designed in the form of an impeller and has a substantially cylindrically designed hub member 26, from the outer cylindrical lateral surface is in the illustrated embodiment, five wings 27 extend in the radial direction to the outside. In this case, the wings 27 may be integrally formed with the hub member 26. Alternatively, the wings 27, as in FIG. 2a shown separately formed and arranged in axially extending, formed on the hub member 26 vane grooves 28, wherein the wings 27 are acted upon by means not shown, between the groove roots of the vane grooves 28 and the vanes 27 arranged spring elements radially outward with a force.

Starting from an outer peripheral wall 29 of the outer rotor 22, a plurality of projections 30 extend radially inwardly. In the illustrated embodiment, the projections 30 are formed integrally with the peripheral wall 29. Conceivable, however, are embodiments in which instead of the projections 30 wings are provided which are mounted on the peripheral wall 29 and extend radially inwardly. The outer rotor 22 is mounted by means of radially inner circumferential walls of the projections 30 relative to the inner rotor 23 rotatably mounted on this.

On an outer circumferential surface of the peripheral wall 29, a sprocket 21 is formed, by means of which a torque can be transmitted from the crankshaft 2 to the outer rotor 22 via a chain drive, not shown. The sprocket 21 may be formed as a separate component and rotatably connected to the inner rotor 23 or formed integrally therewith. Alternatively, a belt or gear drive can be provided.

Depending on one of the side covers 24, 25 is disposed on one of the axial side surfaces of the outer rotor 22 and rotatably fixed thereto. In each of the projections 30, an axial opening 31 is provided for this purpose, wherein each axial opening 31 is penetrated by a fastening element 32, for example a bolt or a screw, which serves for the rotationally fixed fixing of the side cover 24, 25 on the outer rotor 22.

Within the device 10, between each two circumferentially adjacent projections 30, a pressure chamber 33 is formed, which in the circumferential direction of opposite, substantially radially extending boundary walls 34 adjacent projections 30, in the axial direction of the side covers 24, 25, radially inwardly of the hub member 26 and radially outwardly of the peripheral wall 29 is limited. In each of the pressure chambers 33 projects a wing 27, wherein the wings 27 are formed such that they abut both on the side walls 24, 25, and on the peripheral wall 29. Each wing 27 thus divides the respective pressure chamber 33 into two oppositely acting pressure chambers 35, 36.

The outer rotor 22 is rotatably arranged in a defined Winkelbreich to the inner rotor 23. The angular range is limited in one direction of rotation of the inner rotor 23 in that each vane 27 comes into contact with a boundary wall 34 of the pressure space 33 designed as an early stop 34a (early control times). Analogously, the angular range in the other direction of rotation is limited by the fact that each vane 27 comes into contact with the other boundary wall 34 of the pressure chamber 33, which serves as a late stop 34b (late control times). Alternatively, a rotation limiting device may be provided which limits the rotation angle range of the outer rotor 22 to the inner rotor 23.

By pressurizing a group of pressure chambers 35, 36 and depressurizing the other group, the phase angle of the outer rotor 22 to the inner rotor 23 and thus the camshaft 6, 7, to the crankshaft 2 can be varied. By pressurizing both groups of pressure chambers 35, 36, the phase position of the two rotors 22, 23 are kept constant to each other. Alternatively it can be provided to pressurize none of the pressure chambers 35, 36 during phases of constant phase position with pressure medium. As hydraulic pressure medium usually the lubricating oil of the internal combustion engine 1 is used.

During the start of the internal combustion engine 1 or during idling phases, the pressure medium supply of the device 10 may not be sufficient to ensure the hydraulic clamping of the wings 27 within the pressure chambers 33. To an uncontrolled swinging of the inner rotor 23 to the outer rotor 22, a locking mechanism 41 is provided which establishes a mechanical connection between the two rotors 22, 23. In this case, the locking position may lie in one of the end positions of the inner rotor 23 relative to the outer rotor 22. In this case, a rotation angle limiting device 42 is provided, wherein arranged in one of the rotors 22, 23 a locking pin 44 and in the other rotor 22, 23, a link 45 is formed, which is adapted to the locking pin 44. If the inner rotor 23 is in the locking position, then the locking pin 44 can engage in the link 45 and thus produce a mechanical rotationally fixed connection between the two rotors 22, 23.

It has proven to be advantageous to select the locking position so that the wings 27 are in the locked state of the device 10 in a position between the early stop 34a and the late stop 34b. Such a locking mechanism 41 is in FIG. 2a shown. This consists of a first and a second rotational angle limiting device 42, 43. In the illustrated embodiment, each of the rotational angle limiting devices 42, 43 consists of an axially displaceable locking pin 44, wherein each of the locking pins 44 is received in a bore of the inner rotor 23. Furthermore, 24 two scenes 45 are formed in the form of circumferentially extending grooves in the first side wall. These are in FIG. 2a indicated in the form of broken lines. Each of the locking pins 44 is acted upon by means of a spring element 46 with a force in the direction of the first side cover 24. If the inner rotor 23 to the outer rotor 22 assumes a position in which a locking pin 44 faces in the axial direction of the associated link 45, this is forced into the link 45 and the respective rotational angle limiting device 42, 43 transferred from an unlocked to a locked state. Here, the link 45 of the first rotational angle limiting device 42 is designed such that the phase position of the inner rotor 23 is limited to the outer rotor 22, with locked first rotational angle limiting device 42, on a range between a maximum late and the locking position. When the inner rotor 23 is in the locking position relative to the outer rotor 22, the locking pin 44 of the first rotation angle limiting device is located 42 at a trained in the circumferential direction through the gate 45 stop, causing a further adjustment in the direction of earlier control times is prevented.

Similarly, the link 45 of the second rotational angle limiting device 43 is designed such that when locked second rotational angle limiting device 43, the phase angle of the inner rotor 23 is limited to the outer rotor 22 to a range between a maximum early position and the locking position.

In order to transfer the rotational angle limiting devices 42, 43 from the locked to the unlocked state, it is provided that the respective link 45 is subjected to pressure medium. As a result, the respective locking pin 44 is pushed back against the force of the spring element 46 into the bore and thus eliminates the rotation angle limitation.

For pressure medium supply of the adjusting device 11, a plurality of pressure medium lines 38a, b, control lines 48, a control valve 37, a pressure medium pump 47 and a tank 49 are provided.

Inside the inner rotor 23, first and second pressure medium lines 38a, 38b are provided. The first pressure medium line 38a extending from the first pressure chambers 35 to a central receptacle 40 of the inner rotor 23. The second pressure medium line 38b extending from the second pressure chambers 36 also to the central receptacle 40. The pressure medium lines 38a, b are in FIG. 2a for reasons of clarity shown only for two pressure chambers 33.

For pressurizing the rotation angle limiting devices 42, 43 control lines 48 are provided, which extend from a first annular groove 50 in the central receptacle 40 of the inner rotor 23 via the first side cover 24 to the scenes 45. In this case, the first annular groove 50 communicates with the scenes 45 in every phase of the device 10.

Within the receptacle 40 of the inner rotor 23, a control valve 37 is arranged. In the illustrated embodiment, the control valve 37 is received in a hollow camshaft 6,7, which passes through the receptacle 40 of the inner rotor 23. In this case, the inner rotor 23, for example by means of a non-positive or cohesive connection with the camshaft 6,7 rotatably connected.

The control valve 37 has a first and a second working port A, B, an inlet port P, a third working port (control port S) and drain ports T, T _a . Via the inlet connection P, the control valve 37 can be supplied with pressure medium from a pressure medium pump 47. The first and second working ports A, B communicate with the first and second pressure medium lines 38a, b, respectively. The control connection S communicates with the control lines 48. Via the outflow connections T, T _a , pressure medium can be removed from the control valve 37 to a tank 49.

Furthermore, the control valve 37 can be transferred into four control stations S1-S4 ( FIG. 2a ). In the first control position S1, the second working port B communicates with the inflow port P, while both the first working port A and the control port S are connected to the outflow ports T, T _a . This control position S1 is taken during the starting phase of the internal combustion engine 1. In this phase, the hydraulic clamping of the wings 27 is not guaranteed within the pressure chambers 33 due to low system pressure in general. Since the scenes 45 both rotational angle limiting devices 42, 43 via the control lines 48, and the control valve 37 are connected to the tank 49, both rotational angle limiting device 42, 43 take the locked state. Thus, the inner rotor 23 is mechanically connected to the outer rotor 22, whereby the phase position is fixed in the locking position. Since in this position of the control valve 37, the rotation angle limiting devices 42, 43 are not connected to the pressure medium pump 47 but the tank 49, there is no risk of unwanted unlocking. Thereby, the starting ability of the internal combustion engine 1 is secured and at the same time the exhaust emissions are reduced.

The control positions S2-S4 of the control valve 37 represent the control positions of the device 10, in which an adjustment in the direction of later control times (second control position S2) or an adjustment in the direction of early control times (fourth control position S4) or the control times are kept constant (third Control position S3). In these control positions S2-S4, the scenes 45 of the rotation angle limiting devices 42, 43 are connected via the control lines 48 and the control valve 37 to the pressure medium pump 47. As a result, system pressure is applied to the end face of the locking pins 44, as a result of which the rotational angle limiting devices 42, 43 assume the unlocked state and permit phase adjustment of the inner rotor 23 to the outer rotor 22.

In the second control position S2, both the second working port B and the control port S communicate with the inflow port P, while the first working port A is connected to the outflow port T. Thus, 36 pressure medium from the pressure medium pump 47 is supplied via the control valve 37 and the second pressure medium lines 38b the second pressure chambers. At the same time, an outflow of pressure medium from the first pressure chambers 35 via the first pressure medium lines 38a and the control valve 37 to the tank 49. Thus, the wings 27 are moved within the pressure chambers 33 in the direction of the late stops 34b. This results in a relative change in the phase position of the camshaft 6, 7 to the crankshaft 2 in the direction of later timing.

In the third control position S3, only the control connection S communicates with the inlet connection P, while the first and the second working connection A, B are connected neither to the tank 49 nor to the outlet connections T, T _a . Thus, pressure medium is neither directed to the pressure chambers 35, 36 nor discharged from them. The wings 27 are hydraulically clamped, whereby the phase position of the inner rotor 23 is fixed to the outer rotor 22 and thus the camshaft to the crankshaft 2 6.7.

In the fourth control position S4, both the first working port A and the control port S communicate with the inflow port P, while the second working port B is connected to the outflow port T. Thus, via the control valve 37 and the first pressure medium lines 38 a the first pressure chambers 35 pressure medium supplied from the pressure medium pump 47. At the same time there is an outflow of pressure medium from the second pressure chambers 36 via the second pressure medium lines 38b and the control valve 37 to the tank 49. Thus, the wings 27 are moved within the pressure chambers 33 in the direction of the early stops 34a. This results in a relative change in the phase angle of the camshaft 6, 7 to the crankshaft 2 in the direction of early timing.

The control valve 37 is in the FIGS. 3a-d shown. It consists of a not shown actuator and a hydraulic section 51. The hydraulic section 51 consists of a substantially hollow cylindrical valve housing 52 and a control piston 54. The valve housing 52 carries the terminals A, B, P, S, T, T _a . With the exception of the axial outlet connection T _a , the connections A, B, P, S, T are designed as openings in the cylindrical wall of the valve housing 52, which open into annular grooves which are formed on the outer lateral surface of the valve housing 52. The working ports A, B communicate via openings in the camshaft 6, 7 with the first and second pressure medium lines 38a, b. The control port S communicates via openings in the camshaft 6, 7 with the first annular groove 50 of the inner rotor 23, in which the control lines 48 open.

The drain port T communicates via further openings in the camshaft 6, 7 with a second annular groove 53, which is formed in the receptacle 40 of the inner rotor 23. In this case, the second annular groove 53 is connected via an axial bore 39 in connection with the exterior of the adjusting device 11

The connections A, B, P, S, T are axially offset from one another and arranged in the sequence inlet connection P, first working connection A, discharge connection T, second working connection B, control connection S. In this case, apart from the inlet connection P, all connections are arranged within the receptacle 40 (FIG. FIG. 2b ). The inlet connection P projects out of the adjusting device 11 in the axial direction. As a result, the pressure medium outside the adjusting device 11 can be supplied to the control valve 37. Thus eliminates the need within the inner rotor 23 to provide a supply line through which the pressure medium As a result, the architecture of the inner rotor 23 is considerably simplified.

The axial discharge port T _a is formed as an axial opening of the valve housing 52.

The control piston 54 is designed substantially hollow cylindrical and disposed axially displaceable within the valve housing 52. In this case, the axial position of the control piston 54 can be adjusted continuously by means of the adjusting unit, not shown. The actuator acts against the force of a spring 55 which moves the control piston 54 to an initial position when the actuator is inactive. The spring 55 is supported on a spring plate 55a, which is fixed in the axial opening which forms the axial discharge port T _a . The actuator 50 may be formed, for example, as an electrical actuator.

The control piston 54 has four axially spaced control spaces 56a, b, c, d. The control chambers 56a, b, c, d are formed in the illustrated embodiment as annular grooves in the outer circumferential surface of the control piston 54. With the exception of the fourth control chamber 56d, the control chambers 56a, b, c communicate with the interior of the control piston 54 via piston ports 57a, b, c. The control chambers 56a-d are each bounded by two annular webs 58a-e. In this case, the first annular web 58a limits the first control chamber 56a in the direction of the axial outlet port T _a and the fifth annular web 58e the inlet port P in the direction of the actuating unit, not shown. The second ring land 58b separates the first control space 56a from the fourth control space 56d. The third ring land 58c separates the fourth control space 56d from the second control space 56b. The fourth ring land 58d separates the second control space 56b from the third control space 56c.

Depending on the relative position of the spool 54 relative to the valve housing 52, the control spaces 56a-d communicate with various ports A, B, P, S, T, T _a .

The first control chamber 56a is arranged such that communication with the second working port B and the control port S can be established.

The second control chamber 56b is arranged such that communication with the first working port A can be established.

The third control chamber 56c communicates in each position of the control piston 54 with the inlet port P.

The fourth control chamber 56d is arranged such that communication with the second working port B or the first working port A can be established. In this case, the fourth control chamber 56d always communicates with the drain port T.

Based on FIGS. 3a-d the function of the control valve 37 will be explained. The figures differ in the relative position of the control piston 54 relative to the valve housing 52 FIG. 3a the control valve 37 is shown in a state in which the actuator is inactive. The spring 55 urges the control piston 54 in the starting position, in which this rests against a first stop 59. In the following FIGS. 3b-c the control piston 54 is offset relative to the valve housing 52 by an increasing distance against the force of the spring 55.

In the in FIG. 3a shown state of the control valve 37 passes pressure medium via the inlet port P the third control chamber 56c and the third piston openings 57c in the interior of the control piston 54. From there, the pressure medium passes through the first piston openings 57a and the first control chamber 56a to the second working port B. At the same time from the second or third annular web 58b, c a pressure medium flow to the control port S and the first working port A locked. The first working port A is connected by means of the fourth control chamber 56d to the drain port T and the control port S to the axial drain port T _a .

Pressure medium thus passes from the pressure medium pump 47 via the control valve 37 to the second pressure chambers 36, while pressure medium from the scenes 45 and the first pressure chambers 35 is discharged to the tank 49. The Rotation angle limiting devices 42, 43 are consequently in the locked state and thus prevent a phase adjustment of the inner rotor 23 relative to the outer rotor 22.

In FIG. 3b the control piston 54 is deflected relative to the valve housing 52 by the distance x ₁ against the force of the spring 55. Pressure medium, which is supplied to the control valve 37 via the inlet port P, passes via the interior of the control piston 54 to the first control chamber 56a and from there to the second working port B and the control port S. At the same time from the third annular web 58c a pressure medium flow to the first Work port A locked. The first working port A is further connected to the drain port T by means of the fourth control chamber 56d. The first ring land 58a separates the control port S from the axial discharge port T _a . Pressure medium thus passes from the pressure medium pump 47 via the control valve 37 to the second pressure chambers 36 and the scenes 45, while pressure medium is discharged from the first pressure chambers 35 to the tank 49.

Thus, the rotation angle limiting devices 42, 43 are transferred to the unlocked state. At the same time takes place by the flow of pressure medium to the second pressure chambers 36 and the pressure medium discharge from the first pressure chambers 35, a phase adjustment in the direction of later timing instead

In Figure 3c the control piston 54 is deflected relative to the valve housing 52 by the distance x ₂ > x ₁ against the force of the spring 55. Pressure medium, which is supplied to the control valve 37 via the inlet port P, passes via the interior of the control piston 54 to the first control chamber 56a and from there to the control port S. At the same time from the second and third annular web 58b, c a pressure medium flow to both working ports A, B locked. At the same time, the second and third ring lands 58b, c block the connection between each of the working ports A, B and the drain port T. The first ring land 58a further separates the control port S from the axial drain port T _a .

Pressure medium thus passes from the pressure medium pump 47 via the control valve 37 to the scenes 45, while the pressure chambers 35, 36 neither pressure medium supplied, is still removed from these. The adjusting device 11 is thus hydraulically clamped, ie there is no phase adjustment between the inner rotor 23 and the outer rotor 22 instead.

In 3d figure the control piston 54 is deflected relative to the valve housing 52 by the distance x ₃ > x ₂ against the force of the spring 55. Pressure medium, which is supplied to the control valve 37 via the inlet port P, passes via the interior of the control piston 54 to the first control chamber 56a and from there to the control port S. At the same time the pressure medium passes through the interior of the control piston 54 and the second piston openings 57b in the second control chamber 56b and from there to the first working port A. A connection between the inlet port P and the second working port B is blocked by the second annular web 58b. Likewise, a pressure medium flow from the first working port A to the drain port T is blocked by the third annular web 58 c. The second working port B is connected to the drain port T by means of the fourth control chamber 56d. The first ring land 58a further separates the control port S from the axial discharge port T _a .

Pressure medium thus passes from the pressure medium pump 47 via the control valve 37 to the first pressure chambers 35 and the scenes 45, while pressure medium is discharged from the second pressure chambers 36 to the tank 49.

Thus, the rotation angle limiting devices 42, 43 are transferred to the unlocked state. At the same time takes place by the pressure medium flow to the first pressure chambers 35 and the pressure medium outflow from the second pressure chambers 36, a phase adjustment in the direction of later timing instead.

The control valve 37 shown serves, on the one hand, to regulate the phase position of the inner rotor 23 relative to the outer rotor 22. Furthermore, the locking states of the rotational angle limiting devices 42, 43 can be controlled via a separate control connection S. By the separation of the control terminal S from the working ports A, B, the risk of unwanted input or Entriegelns the rotational angle limiting devices 42, 43 is reduced. In addition, the control logic with respect to the control terminal S are performed independently of those of the working ports A, B and thus tailored to the particular application. By the pressure medium supply to one of the working ports B and to the control port S via a common control chamber 56a, the structure of the control piston 54 is simplified. Instead of the five or six control chambers required in the prior art, the control valve 37 has only four control chambers 56a-d with the same functionality. This leads to a significant simplification of the control piston 54. Furthermore, the number of costly to manufacture control edges (limitations of the control spaces 56a-d) is reduced to a minimum. Thus, the control piston 54 can be made cheaper and more reliable. Furthermore, the control piston 54 can be made shorter in the axial direction, as a result of which the space requirement of the control valve 37, which is arranged in installation-critical areas of the internal combustion engine 1, is considerably reduced. This applies both to embodiments as a plug-in valve (arrangement of the control valve 37 outside the adjusting device 11) in which the actuating unit and the hydraulic section 51 are connected to one another, as well as for central valve applications ( FIG. 2b ), in which the hydraulic portion 51 is formed separately from the actuator and disposed in the receptacle 40 of the actuator 11.

Also conceivable are embodiments in which the first working port A and the control port S are arranged reversed.

reference numeral

1

Internal combustion engine

2

crankshaft

3

piston

4

cylinder

5

traction drive

6

intake camshaft

7

exhaust

8th

cam

9a

Inlet gas exchange valve

9b

Auslassgaswechselventil

10

contraption

11

locking device

12

hydraulic system

21

Sprocket

22

outer rotor

23

inner rotor

24

side cover

25

side cover

26

hub element

27

wing

28

vane

29

peripheral wall

30

-

31

axial opening

32

fastener

33

pressure chamber

34

boundary wall

34a

early stop

34b

late stop

35

first pressure chamber

36

second pressure chamber

37

control valve

38a

first pressure medium line

38b

second pressure medium line

39

Axialborung

40

admission

41

locking mechanism

42

Rotational angle limiting device

43

Rotational angle limiting device

44

locking pin

45

scenery

46

spring element

47

Hydraulic pump

48

control line

49

tank

50

first ring groove

51

hydraulic section

52

valve housing

53

second annular groove

54

spool

55

feather

55a

spring plate

56a

first control room

56b

second control room

56c

third control room

56d

fourth control room

57a

first piston opening

57b

second piston opening

57c

third piston opening

58a

first ring bridge

58b

second ring bridge

58c

third ringbridge

58d

fourth ring bridge

58e

fifth ring bridge

59

attack

A

first work connection

B

second work connection

P

inflow connection

S

Control connection T Drain connection

T _a

axialerAblaufanschluss

x ₁ -x ₄

deflection

S1

first control position

S2

second control position

S3

third control position

S4

fourth control position

Claims (10)

1. Device (10) for variably adjusting the timing control of gas exchange valves (9a, 9b) of an internal combustion engine (1), comprising

   - a drive element (22), an output element (23), a rotation angle limiting device (42, 43) and a control valve (37),

   - at least two counter-working pressure chambers (35, 36) being provided,

   - it being possible to bring about a phase adjustment between the output element (23) and the drive element (22) by charging one of the pressure chambers (35, 36) with pressure medium while simultaneously discharging the other pressure chamber (35, 36),

   - the rotation angle limiting device (42, 43) preventing the phase relation from being altered when in a locked state,

   - the rotation angle limiting device (42, 43) allowing the phase relation to be altered when in an unlocked state,

   - it being possible to switch the rotation angle limiting device (42, 43) from the locked to the unlocked state by charging same with pressure medium,

   - the control valve (37) comprising a valve housing (52) and a control piston (54),

   - exactly one inflow port (P), at least one outflow port (T), a control port (S) and two working ports (A, B) being embodied on the valve housing (52),

   - the inflow port (P) being connected to a pressure source (47), the outflow port (T) to a tank, the control port (S) to the rotation angle limiting device (42, 43) and the working ports (A, B) each being connected to a respective pressure chamber (35, 36), and

   - the control valve (37) being arranged in a central receptacle (40) of the output element (23),
   characterized in that

   - the inflow port (P) is arranged outside the output element (23) and the drive element (22) in the axial direction, and

   - the working ports (A, B) and the control port (S) can be selectively connected to or disconnected from the inflow port (P), depending on the position of the control piston (54) within the valve housing (52).
2. Device (2) according to Claim 1, characterized in that the working ports (A, B), the inflow port (P) and the control port (S) are embodied as radial openings in the valve housing (52).
3. Device (2) according to Claim 1, characterized in that the ports (A, B, P, S, T) are offset axially from one another and are arranged in the sequence: inflow port (P), working port (A), outflow port (T), working port (B), control port (S) or: inflow port (P), control port (S), outflow port (T), working port (B), working port (A).
4. Device (2) according to Claim 5, characterized in that a further outflow port (T_a) is embodied as an axial port on the valve housing (52).
5. Device (2) according to Claim 1, characterized in that the control piston (54) is configured to be hollow and the interior of the control piston (54) communicates with the inflow port (P) in all positions of the control piston (54) relative to the valve housing (52).
6. Device (2) according to Claim 1, characterized in that the interior of the control piston (54) can be connected to each of the working ports (A, B) and to the control port (S) by appropriate positioning of the control piston (54) within the valve housing (52).
7. Device (2) according to Claim 4, characterized in that the control valve (37) can adopt a first control position (S1) in which the first working port (A) communicates exclusively with the outflow port (T), the second working port (B) communicates exclusively with the inflow port, and the control port (S) communicates exclusively with the axial outflow port (T_a).
8. Device (2) according to Claim 7, characterized in that the control valve (37) can adopt a second control position (S2) in which the first working port (A) communicates exclusively with the outflow port (T) and the second working port (B) and the control port (S) communicate exclusively with the inflow port.
9. Device (2) according to Claim 8, characterized in that the control valve (37) can adopt a third control position (S3) in which the control port (S) communicates exclusively with the inflow port while the working ports (A, B) communicate neither with the inflow port (P) nor with either of the outflow ports (T, T_a).
10. Device (2) according to Claim 9, characterized in that the control valve (37) can adopt a fourth control position (S4) in which the second working port (B) communicates exclusively with the outflow port (T) and the first working port (A) and the control port (S) communicate exclusively with the inflow port (P).

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