EP2041402B1 - Device for variably adjusting the control times of gas exchange valves of an internal combustion engine - Google Patents

Abstract

The invention relates to a device (10) for variably adjusting control times of gas exchange valves (9a, 9b) of an internal combustion engine (1), comprising an external rotor (22) and an internal rotor (23) that is arranged such that it can rotate in relation to the external rotor. One of the components is drivingly connected to the crank shaft (2) and the other component is drivingly connected to the camshaft (6, 7). At least one pressure chamber (33) is provided and each pressure chamber (33) is divided into two counter-working pressure chambers (35, 36). One of the pressure chambers (35, 36) of each pressure chamber (33) acts as an advance chamber and the other pressure chamber (35, 36) as a trailing chamber. At least two rotation angle limiting devices (42, 43) are provided, each of said rotation angle limiting devices (42, 43) being able to assume an unlocked state and locked state. The locked state can be adjusted by supplying or withdrawing a pressure medium to and from the respective rotation angle limiting devices (42, 43).

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 having an outer rotor and a rotatable inner rotor relative thereto, wherein one of the components in drive connection with the crankshaft and the other component is in driving connection with a camshaft, wherein at least one pressure chamber provided and each pressure chamber is divided into two oppositely acting pressure chambers, wherein one of the pressure chambers of each pressure chamber acts as Voreil- and the other pressure chamber as a retardation chamber, wherein by pressure medium supply to the Voreilkammern, at the same pressure medium outflow of the retard chambers, the rotor cooperating with the camshaft relative is rotated to the cooperating with the crankshaft rotor in the direction of a maximum early position, wherein by pressure medium supply to the lag chambers, with simultaneous pressure medium discharge from the advance chambers, with the camshaft cooperating rotor relative to the cooperating with the crankshaft rotor is rotated in the direction of a maximum late position, wherein at least a first and a second Druckmittekanal are provided, via which the pressure chambers supplied pressure medium, or can be removed from these, wherein at least two rotation angle limiting devices are provided and wherein each rotational angle limiting device can assume an unlocked and a locked state, wherein the locking state can be adjusted by pressure medium supply to and pressure medium discharge from the respective rotational angle limiting devices.

Background of the invention

In modern internal combustion engines devices for variable adjustment of the timing of gas exchange valves are used to make the phase relation between the crankshaft and the camshaft in a defined angular range, between a maximum early and a maximum late position 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 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 in the internal combustion engine 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 position of the rotors targeted or 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. It has been found to be advantageous for the locking position to select a phase angle of the camshaft relative to the crankshaft, which is between the maximum early position and the maximum late position.

Such a device is for example from the US 2003/0121486 A1 known. In this embodiment, the device is designed in a rotary piston type, 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 locking groove is formed, which faces the locking pins in certain operating positions of the devices. In these operating positions, the pins can engage in the locking groove. In this case, the respective rotation angle limiting device moves from the ent to the locked state.

Each of the rotation angle limiting devices can be transferred from the locked to the unlocked state by pressurizing the locking groove. 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 loading of the pressure chambers and the locking groove 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. A disadvantage of the illustrated embodiment, the fact that both Drehwinkelbegrenzungsvorrichtungen be transferred by means of one and the same control line from the locked to the unlocked state. During an adjustment process both Drehwinkelbegrenzungsvorrichtungen must be unlocked in this embodiment, so be acted upon with pressure medium, while the pressure chambers alternately pressure medium to, or is discharged from them. This leads to a complex control logic of the control valve. On the one hand, a plurality of control positions are necessary, wherein the switching points between the control positions during operation of the internal combustion engine, due to operationally occurring variations, for example as a result of temperature changes, must be constantly redetermined. Furthermore, the adjustment of the individual control states requires a higher precision of the control system, since the current to be supplied to the valve is limited due to the large number of control positions Current value intervals has to lie. This results in a variety of computing and data processing operations, making high demands on the control electronics are made. Furthermore, the phase fidelity of the device suffers, since even smaller deviations in the control loop lead to an unwanted control state is set.

Furthermore, it is provided in this embodiment, during the starting phase of the internal combustion engine to connect all pressure chambers and the locking groove with a tank, which leads to a lack of supply of the device with lubricant and thus to increased wear.
Alternatively, in a further embodiment, pressure medium is provided to one of the chambers and thus to ensure a sufficient supply of lubricant. However, in this embodiment, the inner rotor is hydraulically biased against the outer rotor. This can lead to jamming of one of the locking pins on the edges of the locking groove, whereby a hydraulic unlocking difficult or possibly even prevented.

Object of the invention

The invention has for its object to provide a device for variable adjustment of the timing of gas exchange valves of an internal combustion engine, wherein the inner rotor can be mechanically locked relative to the outer rotor in a middle phase position between the maximum early and the maximum retarded position. In this case, a secure locking when stopping the engine or at least be guaranteed during the boot process, unwanted Selbstentriegelung be avoided, the device at any time sufficiently supplied with lubricant and ensure safe adjustment beyond the locking position also, with the individual control states of the control valve easy to determine and to be kept.

According to the invention, the object is achieved in that the Verrieglungszustand the first rotation angle limiting device is controlled solely by the pressure prevailing in at least one of the pressure chambers and that the locking state of the second rotation angle limiting device is controlled by a separate control line, wherein the control line neither with the pressure medium channels still with the pressure chambers communicated.

In a concretization of the invention it is provided that the first rotational angle limiting device communicates via a connecting line with at least one of the pressure chambers or with one of the pressure medium channels.
It can be provided to control the Verrieglungszustand the first rotation angle limiting device exclusively on the prevailing in one or more Voreilkammern pressure.

Advantageously, when the first and second rotational angle limiting devices are locked in place, the inner rotor is fixed relative to the outer rotor in a locking position.
In this case, the second rotational angle limiting device in the locked state, a phase position of the cooperating with the camshaft rotor relative to the cooperating with the crankshaft rotor to an angular range between the maximum early position and the Verrieglungsposition limit.
Furthermore, it can be provided that the first rotational angle limiting device in the locked state prevents the rotation of the cooperating with the camshaft rotor relative to the cooperating with the crankshaft rotor when taking the locking position in the direction of the maximum early position.
In a specific embodiment, it is provided that the first rotational angle limiting device in the locked state limits the phase position of the rotor cooperating with the camshaft relative to the rotor cooperating with the crankshaft to an angular range between the maximum retarded position and the locking position.

Advantageously, a control valve is provided which controls the pressure medium supply to and the pressure medium discharge from the pressure medium channels and the control line.

In this case, the control valve has two working ports, wherein the first working port communicates with the first pressure chambers and the second working port communicates with the second pressure chambers, and wherein the control line communicates valve side exclusively with a separately designed to the working ports control port.

In the embodiment of the device according to the invention a locking device is provided by means of which the outer rotor with the inner rotor in a locking position between a maximum early and a maximum late position is mechanically coupled. Advantageously, two Drehwinkelbegrenzungsvorrichtungen be provided, wherein one of the rotational angle limiting devices in the locked state, the relative phase angle of the inner rotor to the outer rotor limited to a range between the maximum early and the locking position. The other rotation angle limiting device allows in the locked state a phase angle between the locking and the maximum late position. Alternatively, this may be embodied as a locking element, wherein a locking pin of the locking element engages in the locking position in a recess adapted to the locking pin or a blind hole. This ensures that the inner rotor can be mechanically fixed relative to the outer rotor in a middle phase position.
Each of the rotation angle limiting devices can be transferred by pressure medium from the locked to the unlocked state. In this case, the rotation angle limiting device, which limits the relative rotation of the inner rotor to the outer rotor in the locked state to a region between the maximum early and the locking position communicates with a control line, wherein the other rotation angle limiting device, for example via a worm groove, communicates with at least one of the pressure chambers. Advantageously, the control line is separate from the Pressure medium lines and the pressure medium channels executed, which supply the pressure chambers with pressure medium. Thus, the locking states of the rotation angle limiting devices can be set independently of each other. Since one of the rotation angle limiting devices is supplied with pressure medium via at least one of the pressure chambers, the number of control positions which have to be provided on the control valve can be reduced to a minimum. Thus, the number of switching points to be determined decreases, whereby the control effort during operation of the internal combustion engine drops significantly. Furthermore, the ranges of the individual control positions of the control valve designed as a proportional valve can be increased, which in turn reduces the control effort and increases the reliability.

By the separate control of one of the rotation angle limiting device via a control line, it is also possible the device during the shutdown in a defined interval, which includes the Verrieglungsposition turn off. Already during the shutdown process or alternatively during the restart of the internal combustion engine, the inner rotor automatically enters the locking position, wherein the mechanical connection between the rotors is produced by means of the rotation angle limiting devices.

Since the control line is formed independently of the pressure medium lines supplying the device, both rotational angle limiting devices can be connected to the tank during the starting phase, wherein a pressure medium channel communicates neither with the tank nor with the pump. Thus, an automatic unlocking of the device can be prevented. At the same time, the leakage oil entering via the control valve into the pressure medium lines can be sucked in by a small oscillating movement of the inner rotor relative to the outer rotor, whereby an adequate supply of lubricant to the device is ensured even during the starting phase. The low oscillatory movement of the inner rotor to the outer rotor results from the acting on the camshaft alternating torques in combination with a small locking clearance of the rotation angle limiting devices.

Brief description of the drawings

Figur 1

nur sehr schematisch eine Brennkraftmaschine,

Figur 2a

einen Querschnitt durch eine erfindungsgemäße Ausführungsform einer Vorrichtung zur Veränderung der Steuerzeiten von Gaswechselventilen einer Brennkraftmaschine incl. einem angeschlossenen Hydraulikkreislauf,

Figur 2b

einen Längsschnitt durch die Vorrichtung aus Figur 2a entlang der Linie II b-II b,

Figur 2c

einen Querschnitt durch die Vorrichtung aus Figur 2b entlang der Linie IIc-IIc,

Figur 3

eine erste Steuerlogik eines Steuerventils der erfindungsgemäßen Vorrichtung,

Figur 4

eine zweite Steuerlogik eines Steuerventils der erfindungsgemäßen Vorrichtung,

Figur 5

ein Steuerventil zur Steuerventil zur Steuerung der erfindungsgemäßen Vorrichtung in perspektivischer Ansicht,

Figur 6

einen Teillängsschnitt durch das Steuerventil aus Figur 5,

Figur 6a-6g

einen Längsschnitt durch die wesentlichen Teile des Steuerventils aus Figur 6 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

a cross section through an inventive embodiment of a device for changing the timing of gas exchange valves of an internal combustion engine incl. An attached hydraulic circuit,

FIG. 2b

a longitudinal section through the device FIG. 2a along the line II b-II b,

Figure 2c

a cross section through the device FIG. 2b along the line IIc-IIc,

FIG. 3

a first control logic of a control valve of the device according to the invention,

FIG. 4

a second control logic of a control valve of the device according to the invention,

FIG. 5

a control valve to the control valve for controlling the device according to the invention in a perspective view,

FIG. 6

a partial longitudinal section through the control valve FIG. 5 .

Figure 6a-6g

a longitudinal section through the essential parts of the control valve FIG. 6 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 transverse or in longitudinal section.
The device 10 has an outer rotor 22, an 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, extend from the outer cylindrical surface in the illustrated embodiment, five wings 27 in the radial direction outwards. 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, formed on the hub member 26, axially extending vane grooves 28, wherein the wings 27 are acted upon by means not shown, arranged between the groove roots of the vane grooves 28 and the wings 27 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 arranged, by means of which, via a chain drive, not shown, torque can be transmitted from the crankshaft 2 to the outer rotor 22. 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 space 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 bounded by the peripheral wall 29. 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 a rotational direction of the outer rotor 22 in that each wing 27 at one as early stop 34 a trained boundary wall 34 of the pressure chamber 33 comes to rest. Similarly, the angular range in the other direction of rotation is limited by the fact that each wing 27 comes to rest on the other boundary wall 34 of the pressure chamber 33, which serves as a late stop 34b. 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 pressure relief of the other group, the phase angle of the outer rotor 22 to the inner rotor 23 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.
For pressure medium supply to or pressure medium removal from the pressure chambers 35, 36, a pressure medium system is provided which comprises a pressure medium pump, not shown, a likewise not shown tank, a control valve 37 and a plurality of pressure medium lines 38a, 38b, 38p. Pressure medium conveyed by the pressure medium pump is supplied to the control valve 38 via the third pressure medium line 38p. Depending on the control state of the control valve 37, the third pressure medium line 38p with the first pressure medium line 38a, the second
Pressure medium line 38b or connected to both or none of the pressure medium lines 38a, 38b.
The inner rotor 23 is formed with two groups of pressure medium channels 39a, 39b, wherein each pressure medium channel 39a, 39b extends from an inner lateral surface of a receptacle 40 of the inner rotor 23 to one of the pressure chambers 35, 36. The first pressure medium line 38a communicates with the first pressure medium channels 39a. The second pressure medium line 38b communicates with the second pressure medium channels 39b. For this purpose, for example, a pressure medium distributor may be provided, which is arranged in the receptacle 40. In an alternative embodiment, the control valve 37 is formed as a central valve and arranged in the receptacle 40, in which case the Control valve 37, the third pressure medium line 38p connects directly to the pressure medium channels 39a, 39b.

In order to shift the control times (opening and closing times) of the gas exchange valves 9a, 9b in the direction early, the pressure medium supplied to the control valve 37 via the third pressure medium line 38p via the first pressure medium channels 39a and optionally the first pressure medium line 38a to the group of the first pressure chambers 35th directed. At the same time, pressure medium from the group of second pressure chambers 36 reaches the control valve 37 via the second pressure medium channels 39b and optionally the second pressure medium line 38b and is ejected into the tank. As a result, the wings 27 are displaced in the direction of the early stop 34a, whereby a rotary movement of the inner rotor 23 to the outer rotor 22 in the direction of rotation of the device 10 is achieved.
In order to shift the timing of the gas exchange valves 9a, 9b in the direction of late, the pressure medium supplied to the control valve 37 via the third pressure medium line 38p via the second pressure medium channels 39b and optionally the second pressure medium line 38b to the group of second pressure chambers 36. At the same time, pressure medium from the group of the first pressure chambers 35 reaches the control valve 37 via the first pressure medium channels 39a and optionally the first pressure medium line 38a and is ejected into the tank. As a result, the wings 27 are displaced in the direction of the late stop 34a, whereby a rotary movement of the inner rotor 23 to the outer rotor 22 opposite to the direction of rotation of the device 10 is achieved.
In order to keep the control times constant, the pressure medium supply to all pressure chambers 35, 36 is either prevented or permitted. As a result, the wings 27 are hydraulically clamped within the respective pressure chambers 33, and thus prevents a rotational movement of the inner rotor 23 to the outer rotor 22.

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, a locking pin is arranged in one of the rotors 22, 23, while in the other rotor 22, 23 a link is formed. If the inner rotor 23 is in a defined phase position (locking position) relative to the outer rotor 22, then the locking pin can engage in the connecting link 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 Figure 2c 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 Figure 2c 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. If the inner rotor 23 is in the locking position relative to the outer rotor 22, then the locking pin 44 of the first rotational angle limiting device 42 bears against a stop formed in the circumferential direction by the link 45, whereby 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.
In the illustrated embodiment, it is provided, the backdrop 45 of the first rotation angle limiting device 42, which prevents the rotation of the inner rotor 23 to the outer rotor 22 at the locking position in the direction of early in the locked state via one of the first pressure chambers 35 and a connecting line 47 with pressure medium. The link 45 of the second rotational angle limiting device 43 can be acted upon by the pressure medium via the control line 48 and the channel 49. It is provided that the control valve 37 controls both the pressure medium flows to and from the first and second pressure chambers 35, 36, as well as to and from the control line 48.

Such a control valve 37 is in the FIGS. 5 and 6 shown. The control valve 37 consists of an actuating unit 50 and a hydraulic section 51. The hydraulic section 51 consists of a valve housing 52 of an intermediate sleeve 53 and a control piston 54. On the valve housing 52 is a first working port A, a second working port B, an inlet port P, a control port S, an axial and a radial drain port T formed. The first working port A communicates with the first pressure medium line 38a. The second. Work port B communicates with the second pressure medium line 38b. The inlet connection P communicates with the third pressure medium line 38p. The control terminal S communicates with the control line 48. About the drain connections T can flow off pressure medium into a tank (not shown).

The intermediate sleeve 53 is disposed within the valve housing 52, fixed thereto. On the outer circumferential surface of a working groove 56, a control groove 57, five working openings 56a-e and three control openings 57a-c are formed. The working groove 56 and the control groove 57 extend in the circumferential direction of the intermediate sleeve 53 in each case a defined angular interval, wherein the two grooves 56, 57 are hydraulically separated from each other. The working ports A, B and the inlet port P are formed as radial openings in the valve housing 52, wherein the radial openings are formed exclusively in the area occupied by the working groove 56 angle segment. Similarly, the control terminal S is realized by means of one or more radial openings, which are formed exclusively in the region of the angle segment occupied by the control groove 57.
The working opening 56a-e communicate on the one hand with the interior of the intermediate sleeve 53 and on the other hand with the first working port A (first working opening 56a), the inflow port P (second working port 56b), the working groove 56 (third and fourth working port 56c, d) and radial tank connection T (fifth working opening 56e). The working groove 56 additionally communicates with the second working connection B. Furthermore, it is possible to provide further grooves in the outer lateral surface of the intermediate sleeve 53, which form the first, the second or the fifth working opening 56 a, b, e with the respective connection A, P, T combines.
The control openings 57a-c communicate on the one hand with the inner of the intermediate sleeve 53 and on the other hand with the control groove 57, which in turn communicates with the control port S.

The control piston 54 is designed substantially hollow cylindrical and disposed within the intermediate sleeve 53, wherein this is displaceable by the actuator 50 against the force of a spring 55 in the axial direction relative to the intermediate sleeve 53 and the valve housing 52. The control piston 54 has three annular grooves 58a-c, first and second openings 59a, b.

The actuating unit 50 may be formed, for example, as an electrical actuating unit, wherein a magnetized armature is arranged within a coil. By energizing the coil, the armature can be moved within in the axial direction. About a push rod 50 a, this movement can be transmitted to the control piston 54.

By axial displacement of the control piston 54 within the intermediate sleeve 53, the working ports A, B and the control port S can be selectively connected to the inlet port P, the drain port T or neither.

In FIG. 3 is a control logic of in FIG. 5 respectively. FIG. 6 shown control valve 37 shown. In this case, the connections of the first working port A, the second working port B and the control port S with the pressure medium pump or the tank depending on the excitation of the actuator 50 and the axial deflection D of the control piston 54 within the intermediate sleeve 53 are shown. The control logic can be subdivided into seven control positions. In this case, the control valve 37 with increasing excitation of the actuator 50 (axial displacement of the control piston 54) passes through the control positions in the order starting position S1, unlocking S2, Nacheilstellung, S3, first intermediate position S4, stop position S5, second intermediate position S6 and advance position S7. The positions of the control piston 54 relative to the valve housing 52 and the intermediate sleeve 53 in the various control positions S1-S7 are in the Figures 6a-g shown.

In the starting position S1 ( FIG. 6a ), which occupies the control valve 37 in the energized actuator 50, the first working port A (via the first working port 56a) and the control port S (via the first control port 57a) is connected to the axial discharge port T. Thus, pressure medium from the first pressure chambers 35, and thus from the first rotation angle limiting device 42, and from the second rotation angle limiting device 43 for Tank discharged. The second working port B is closed (not connected to the inlet or outlet port P, T).
During the transition from the starting position S1 to an unlocking position S2 (FIG. FIG. 6b ) becomes the control port S (via the second working port 56b, the first annular groove 58a, the first port 59a, the interior of the spool 54, the second port 59b, the third annular groove 58c, the second control port 57b, and the cam groove 57) with the pump connected. The first working port A further communicates with the axial discharge port T, while the second working port B is still closed (analogous to FIG. 6a ).
In the subsequent trailing position S3 ( FIG. 6c ) is the second working port B (via the second working port 56b, the second annular groove 58b, the third working port 56c and the working groove 56), and the control port S connected to the inlet port P (analog FIG. 6b ), wherein the first working port A is connected to the axial outlet port T (analog FIG. 6a ).
In the first intermediate position S4 ( FIG. 6d ), the first working port A is closed, while the second working port B and the control port S are connected to the inlet port P (analog FIG. 6c ).
In the stop position S5 ( FIG. 6e ) Both working ports A, B and the control port S are closed.
In the second intermediate position S6 ( FIG. 6f ) is the first working port A (via the second working port 56b, the first annular groove 58a and the first working port 56a) connected to the inlet port P, while the second working port B and the control port S are closed (analog FIG. 6e ).
In the subsequent advance position S7 ( FIG. 6g ) is the second working port B, and the control port S (via the fourth working port 56d and the third control port 57c, the interior of the intermediate sleeve 53 and the fifth working port 56e), with the radial outlet port T and the first working port A with the inlet port P. connected (analog FIG. 6f ).

During the starting phase of the internal combustion engine 1, the control valve 37 is in the starting position S1. 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. For this reason, the inner rotor 23 will perform oscillatory movements with respect to the outer rotor 22 in the circumferential direction. These oscillations are caused by the alternating torques acting on the camshaft 6, 7, the oscillations occurring even in the locked state of the device 10. Their amplitude is determined by the locking game. The oscillations result in a pumping action whereby residual oil present in the pressure medium channels 39a, b or the pressure medium lines 38a, b can be conveyed into the pressure chambers 35, 36. In this case, 10 pressure values can be achieved within the device, which are sufficient to convert the rotational angle limiting devices 42, 43 in the unlocked state.
By connecting the first working port A and the control port S to the tank this is prevented. The first pressure chambers 35, the corresponding pressure medium channels 39a, the first pressure medium line 38a and the control line 48 are emptied and thus a pressure build-up, and thus the unwanted Selbstentriegelung during the start phase, in the scenes 45 of the rotation angle limiting devices 42, 43 prevented.

Since in the starting position S1, the second working port B is closed, the second pressure chambers 36 are not acted upon by pressure medium. This prevents that the locking pin 44 of the second rotation angle limiting device 43 is urged against the end of the link 45, which could lead to jamming. On the other hand, it is prevented that the pressure medium in the second pressure medium channels 39b can flow to the tank. This ensures that 27 small amounts of pressure medium are promoted by the oscillations of the wings in the second pressure chambers 36, whereby the device 10 is sufficiently supplied with lubricant.

After the lapse of a defined period of time after which the starting process has ended completely or if there is a sufficient pressure level in the lubricant circuit is detected in the internal combustion engine 1, and the engine controller specifies a phase change, the device 10 is in a controlled state until the pressure in the lubricant circuit falls again below a predetermined level. For this purpose, the control unit 50 of the control valve 37 is energized such that it passes through the unlocking position S2 in the control positions S3 to S7 and is regulated depending on the specification of the phase angle by the motor control in one of these control positions S3-S7.

While the control valve 37 occupies the Entriegelstellung S2, in contrast to the starting position S1 of the control port S is subjected to pressure medium and thus transferred the second rotational angle limiting device 43 in the unlocked state. In this case, none of the pressure chambers 35, 36 is pressurized, whereby jamming of the locking pin 44 of the second rotation angle limiting device 43 is prevented in its backdrop 45.

Depending on the current desired or actual values of the phase position, the control valve 37 assumes the control positions S3-S7 in the regulated state of the device 10. If the engine control unit specifies a shift in the phase position in the direction of later intake times, the control valve 37 is energized in such a way that it assumes the retard position S3. In this position, the first pressure chambers 35 are connected to the tank and the second pressure chambers 36 are connected to the pump. At the same time pressure medium is directed to the backdrop 45 of the second rotation angle limiting device 43. The locking pin 44 of the second rotation angle limiting device 43 is held in the unlocked state, while the pressure medium loading of the second pressure chambers 36 leads to a rotation of the inner rotor 23 relative to the outer rotor 22 against the direction of rotation of the device 10 with simultaneous emptying of the first pressure chambers 35. Does the engine control unit before the phase position of the inner rotor 23 to hold relative to the outer rotor 22, the control valve 37 is transferred to the holding position S5. In this position, no pressure medium exchange between the pressure chambers 35, 36 and the backdrop 45 of the second rotation angle limiting device 43 with the tank or the pressure medium pump instead. The wings 27 are hydraulically in the pressure chamber 33rd clamped and held the rotational angle limiting devices 42, 43 in the unlocked position.

If the engine control unit specifies earlier control times, the control valve 37 is brought into the advance position S7. In this control position, the pressure medium is supplied to the first pressure chambers 35, while pressure medium is discharged from the gate 45 of the second rotation angle limiting device 43 as well as from the second pressure chambers 36 to the tank. As a result, a relative rotation of the inner rotor 23 to the outer rotor 22 in the direction of rotation of the device 10 is effected. In addition, the locking pin 44 of the second rotation angle limiting device 43 engage in the corresponding link 45 when they face each other.

In the intermediate positions S4 and S6, a group of the pressure chamber 35, 36 is acted upon by pressure medium, while no pressure medium exchange takes place between the other group of pressure chambers 35, 36 and the pump and the tank. It is thereby achieved that the hydraulic clamping of the vanes 27 within the pressure chambers 33 is maintained during the taking of the holding position S5 or its leaving.

During the stop phase of the internal combustion engine 1, the control valve 37 is transferred to the advance position S7 and kept a defined period beyond their standstill in this. As a result, pressure medium is conducted to the first pressure chambers 35, while pressure medium from the second pressure chambers 36 can flow to the tank. This causes a relative rotation of the inner rotor 23 to the outer rotor 22, wherein the inner rotor 23 comes to a position between the locking position and the maximum early position. At the same time, the control port S and thus the link 45 of the second rotational angle limiting device 43 are connected to the tank, whereby the second rotational angle limiting device 43 is transferred to the locked state. This ensures that the inner rotor 23 during the entire stop and the break of the internal combustion engine 1 in a position adjusted between the locking position and the maximum early position and then held in this.
In the last phase of the engine stop, in which the device 10 is no longer sufficiently supplied with pressure medium, the inner rotor 23 is rotated, due to the drag torques acting on the camshaft 6, 7, relative to the outer rotor 22 in the direction of the maximum retarded position. This movement is stopped by the locked second rotation angle limiting device 43 at the locking position. Due to the lack of system pressure, the first rotation angle limiting device 42 is also transferred in this position in the locked state, whereby a mechanical fixing of the inner rotor 22 is made relative to the outer rotor 23 in the locking position.
Alternatively, this process can take place during the starting phase of the internal combustion engine 1, in which the control valve 37 assumes the starting position S1. In this position, the first pressure chambers 35 and connected to this backdrop 45 of the first rotation angle limiting device 42 are connected to the tank. The inner rotor 22 is urged into the locking position due to the drag torques acting on the camshaft 6, 7, in which the first rotational angle limiting device 42 can transition to the locked state.

During the controlled operation of the device 10 (control states S3-S7) is due to the in FIG. 3 ensures that when a group of pressure chambers 35, 36, the associated rotational angle limiting device 42, 43 is in the unlocked state. Thus, a secure adjustment of the device 10 over the locking position is guaranteed.

Due to the separate control of the rotation angle limiting devices 42, 43, only a small number of switching points exist in the control logic, which are stored in the engine control unit or must be determined by this. At the same time, the areas of the individual control positions S1-S7 increase, whereby the control of the control valve 37 is considerably simplified and the susceptibility to errors is reduced.

FIG. 4 shows one to the in FIG. 3 The control logic shown alternative control logic, the only difference is that the order of the control positions S1-S7 are reversed. The starting position S1 is taken in this embodiment at maximum energized actuator 50, while the advance position S7 is taken at non-energized actuator 50.

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

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

head Start

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

38b

first pressure medium line

38a

second pressure medium line

38p

third pressure medium line

39b

first pressure medium channel

39a

second pressure medium channel

40

admission

41

locking mechanism

42

Rotational angle limiting device

43

Rotational angle limiting device

44

locking pin

45

scenery

46

spring element

47

connecting line

48

control line

49

channel

50

actuator

50a

pushrod

51

hydraulic section

52

valve housing

53

intermediate sleeve

54

spool

55

feather

56

working groove

56a

first work opening

56b

second work opening

56c

third work opening

56d

fourth work opening

56e

fifth work opening

57

control groove

57a

first control opening

57b

second control opening

57c

third control opening

58a

first ring groove

58b

second annular groove

58c

third annular groove

59a

first opening

59b

second opening

A

first work connection

B

second work connection

P

inflow connection

T

drain connection

S

control connection

D

deflection

S1

start position

S2

unlocking

S3

trailing position

S4

first intermediate position

S5

holding position

S6

second intermediate position

S7

lead position

Claims (9)

1. Device (10) for the variable setting of the control times of gas exchange valves (9a, 9b) of an internal combustion engine (1), with

   • an outer rotor (22) and an inner rotor (23) arranged rotatably in relation to the latter, one of the components being drive-connected to a crankshaft (2) and the other component being drive-connected to a camshaft (6, 7),

   • at least one pressure space (33) being provided, and each pressure space (33) being subdivided into two pressure chambers (35, 36) acting in opposition to one another,

   • one of the pressure chambers (35, 36) of each pressure space (33) acting as a leading chamber and the other pressure chamber (35, 36) acting as a trailing chamber,

   • by the supply of pressure medium to the leading chambers, at the same time with the outflow of pressure medium from the trailing chambers, the rotor (22, 23) which cooperates with the camshaft (6, 7) being rotated in the direction of a maximum advanced position in relation to the rotor (22, 23) which cooperates with the crankshaft (2),

   • by the supply of pressure medium to the trailing chambers, at the same time with the outflow of pressure medium from the leading chambers, the rotor (22, 23) which cooperates with the camshaft (6, 7) being rotated in the direction of a maximum retarded position in relation to the rotor (22, 23) which cooperates with the crankshaft (2),

   • at least a first and a second pressure-medium duct (39a, 39b) being provided, via which pressure medium can be supplied to the pressure chambers (35, 36) or can be discharged from these,

   • at least two rotary-angle limitation devices (42, 43) being provided,

   • each rotary-angle limitation device (42, 43) being capable of assuming an unlocked or a locked state, the locking state being capable of being set by the supply of pressure medium to or the discharge of pressure medium from the respective rotary-angle limitation devices (42, 43),

   characterized in that

   • the locking state of the first rotary-angle limitation device (42) is controlled solely via the pressure prevailing in at least one of the pressure chambers (35, 36), and in that

   • the locking state of the second rotary-angle limitation device (43) is controlled by means of a separate control line (48),

   • the control line (48) not communicating either with the pressure-medium ducts (39a, 39b) or with the pressure chambers (35, 36).
2. Device (10) according to Claim 1, characterized in that the first rotary-angle limitation device (42) communicates via a connecting line (47) with at least one of the pressure chambers (35, 36) or with one of the pressure-medium ducts (39a, 39b).
3. Device (10) according to Claim 1, characterized in that the locking state of the first rotary-angle limitation device (42) is controlled solely via the pressure prevailing in one or more leading chambers.
4. Device (10) according to Claim 1, characterized in that, with the first and the second rotary-angle limitation device (42, 43) being locked, the inner rotor (32) is fixed in a locking position in relation to the outer rotor (22).
5. Device (10) according to Claim 4, characterized in that, in the locked state, the second rotary-angle limitation device (43) restricts a phase position of the rotor (22, 23) which cooperates with the camshaft (6, 7) in relation to the rotor (22, 23) which cooperates with the crankshaft (2) to an angular range between the maximum advanced position and the locking position.
6. Device (10) according to Claim 4, characterized in that, in the locked state, the first rotary-angle limitation device (42) prevents the rotation of the rotor (22, 23) which cooperates with the camshaft (6, 7) in relation to the rotor (22, 23) which cooperates with the crankshaft (2) in the direction of the maximum advanced position when the locking position is assumed.
7. Device (10) according to Claim 4, characterized in that, in the locked state, the first rotary-angle limitation device (42) restricts the phase position of the rotor (22, 23) which cooperates with the camshaft (6, 7) in relation to the rotor (22, 23) which cooperates with the crankshaft (2) to an angular range between the maximum retarded position and the locking position.
8. Device (10) according to Claim 1, characterized in that a control valve (37) is provided, which controls the supply of pressure medium to and the outflow of pressure medium from the pressure-medium ducts (39a, 39b) and the control line (48).
9. Device (10) according to Claim 8, characterized in that the control valve (37) has two working connections (A, B), the first working connection (A) communicating with the first pressure chambers (35) and the second working connection (B) communicating with the second pressure chambers (36), and the control line (48) communicating on the valve side solely with a control connection (S) formed separately from the working connections (A, B).

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