EP2478189B1 - Valve opening time phasing device for internal combustion engine - Google Patents

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 hydraulic phase adjusting device and at least one volume memory, wherein the phase adjusting device can be brought into driving connection with a crankshaft and a camshaft and at least one Frühverstellkammer and at least one retardation has, which via pressure medium lines pressure medium supplied or can be discharged from these, wherein by pressure medium supply to the advance chamber at the same pressure medium discharge from the retard a phase angle of the camshaft relative to the crankshaft in the direction of early timing can be adjusted by pressure medium supply to the retardation with simultaneous pressure fluid discharge from the Frühverstellkammer a phase the camshaft can be adjusted relative to the crankshaft in the direction of later timing, wherein the or Volume accumulators can be supplied during operation of the internal combustion engine pressure medium.

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 position of a camshaft relative to a crankshaft in a defined angular range, between a maximum early and a maximum late position variable. For this purpose, a hydraulic phase adjusting device the device 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. Essential characteristics of such devices are the Phasenverstellgeschwindigkeit and the need for pressure medium. In order to be able to optimally adapt the phase position to the different driving situations, high phase adjustment speeds are desirable. Furthermore, in the context of consumption reduction measures, an ever lower pressure medium requirement is required to be able to design the pressure medium pump of the internal combustion engine smaller or to be able to reduce the delivery rate when using regulated pressure medium pumps.

Such a device is for example from the EP 0 806 550 A1 known. The device comprises a vane-type phase-adjusting device with a drive element, which is in drive connection with the crankshaft, and an output element, which is non-rotatably connected to the camshaft. Within the phase adjusting device a plurality of pressure chambers are formed, wherein each of the pressure chambers is divided by means of a wing into two counteracting pressure chambers. By supplying pressure medium to or pressure medium discharge from the pressure chambers, the wings are displaced within the pressure chambers, whereby a change in the phase position between the output element and the drive element takes place. In this case, the pressure medium required for the phase adjustment is provided by a pressure medium pump of the internal combustion engine and directed by means of a control valve selectively to the early or late adjustment. The pressure medium flowing out of the phase adjusting device is directed into a pressure medium reservoir, the oil sump of the internal combustion engine. The phase adjustment thus takes place by means of the system pressure provided by the pressure medium pump of the internal combustion engine.

Another device is for example from the US 5,107,804 A known. In this embodiment, the phase adjusting device is also formed in Flügelzellenbauart and several early or late adjustment provided. Unlike the EP 0 806 550 A1 the phase adjustment is not done by pressurizing the pressure chambers by a pressure medium pump, but it is exploited alternating torques acting on the camshaft. The alternating moments are caused by the rolling of the cams on each biased with a valve spring gas exchange valves. The rotational movement of the camshaft is braked during the opening of the gas exchange valves and accelerated during closing. These alternating moments are transmitted to the phase adjusting device, so that the wings are periodically applied in the direction of the late and early attack with a force. As a result, pressure peaks are generated alternately in the advance chambers and the retard chambers. If the phase position is to be kept constant, then a flow of pressure medium from the pressure chambers is prevented. In the case of a phase adjustment in the direction of earlier control times, a drainage of pressure medium from the advance chambers is prevented, even at the times in which pressure peaks are generated in the advance chambers. Increases due to the alternating moments of the pressure in the retardation, so this pressure is used to direct pressure medium from the retardation under the pressure of the generated pressure peak in the advance chambers. Analog succeeds a phase adjustment in the direction of later timing. In addition, the pressure chambers are connected to a pressure medium pump, but only to compensate for leaks from the phase adjusting device. The phase adjustment is thus carried out by diverting pressure medium from the pressure chambers to be emptied into the pressure chambers to be filled under the pressure of the generated pressure peak.

Another device is from the US 2009/0133652 A1 known. In this embodiment, a phase adjustment takes place at low alternating torques, analogous to the device of the EP 0 806 550 A1 , By pressurizing the Frühverstellkammern or Spätverstellkammern by a pressure medium pump, at the same pressure medium discharge from the other pressure chambers to the oil sump of the internal combustion engine. At high alternating torques, analogous to the device from the US 5,107,804 A , these used to direct the pressure medium under high pressure from the Frühverstellkammern (Spätverstellkammern) in the Spätverstellkammern (Frühverstellkammern). In this case, the pressure medium ejected from the pressure chambers is returned to a control valve which controls the pressure medium supply to or the pressure medium discharge from the pressure chambers. This pressure medium passes via check valves within the control valve to the inlet connection, which is connected to the pressure medium pump, wherein a portion of the pressure medium is ejected into the pressure medium reservoir of the internal combustion engine.

The document EP1607590 A1 discloses an internal combustion engine with a hydraulic device (1) for adjusting the rotational angle of a camshaft relative to a crankshaft with a rotor arranged thereon wings and a rotatably connected to a drive wheel stator. The rotor and the stator form pressure chambers with one another, which can be filled with hydraulic fluid via a hydraulic fluid system, wherein a volume accumulator is arranged in the hydraulic fluid system. Therefore, this volume storage is based on the object to reduce pressure fluctuations as far as possible in a hydraulic fluid circuit provided with a device for adjusting the rotational angle and thus to eliminate in particular pressure peaks.

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, the Phasenverstellgeschwindigkeit to be increased.

Solution of the task

The object is achieved in that in addition at least two pressure medium channels are provided, the first pressure fluid channel on the one hand into one of the volume memory and on the other hand communicates with the Frühverstellkammer, the second pressure fluid channel on the one hand into one of the volume memory and on the other hand communicates with the retardation and each of the pressure medium channels is associated with a check valve, which prevents a pressure medium flow from the respective pressure chamber to the volume memory and can allow a reverse pressure medium flow.

The device has a hydraulic phase adjusting device which has at least two mutually acting pressure chambers, at least one advance chamber and at least one retard adjustment chamber. In this case, the invention is applicable to any type of hydraulic phase adjusting device, such as vane-type devices, such as in the EP 0 806 550 A1 disclosed as Axialkolbenversteller, such as in the DE 42 18 078 C1 discloses, or as Schwenkhebelversteller, such as in the US 4,903,650 A disclosed.
The phase adjusting device has at least one drive element and an output element, wherein the drive element is in drive connection with a crankshaft of the internal combustion engine, for example via a chain, belt or gear drive. The output element is in drive connection with the camshaft. This can for example also be realized by a chain, belt or gear drive or a rotationally fixed connection between the camshaft and output element.
By means of pressure medium line is supplied to the pressure chambers and discharged from these. The pressure medium can for example be provided by a pressure medium pump of the internal combustion engine and the pressure medium to be discharged from the pressure chambers can be passed into a pressure medium reservoir, for example the oil sump of the internal combustion engine. Thus, the phase angle of the device can be variably adjusted even at low alternating torques.
The device also has one or more volume storage for receiving pressure medium. The pressure medium can be stored without pressure or under pressure in the volume store (s). During operation of the internal combustion engine, the pressure medium is supplied to the volume accumulator (s).
In addition to the pressure medium lines which connect the pressure chambers with the pressure medium pump and the pressure medium reservoir, at least two pressure medium channels are provided, which connect the one or more volume memory with the pressure chambers. In this case, one end of each pressure medium channel opens into one of the volume accumulators, the other end of the first pressure medium channel communicating with the one or more advance chambers and the other end of the second pressure medium channel communicating with the retard chamber (s). In this case, the first pressure medium channel communicates exclusively with the or the advance chambers and not with the late adjustment chambers. Analogously, the second pressure medium channel communicates exclusively with the retardation chambers or chambers and not with the advance chambers.
Conceivable, for example, embodiments with only one volume memory, which communicates via the pressure medium channels with all the pressure chambers. Likewise conceivable are embodiments in which a plurality of volume reservoirs are provided. In this case, for example, a part of the volume memory communicate exclusively with the advance chambers while another portion of the volume memory communicates exclusively with the retard chambers. It is also conceivable that each volume memory two pressure chambers, for example, a Frühverstellkammer and a Spätverstellkammer are assigned, with which the respective volume memory communicates via the pressure medium channels.
In addition to the embodiments in which two pressure medium channels are provided, wherein the first / second pressure medium channel communicates with all early / late adjustment, several pressure medium channels may be provided, for example, a pressure medium channel per pressure chamber. Alternatively, it can be provided that a first (early) retardation chamber communicates via a pressure medium channel with a volume accumulator and the other (early) retard chambers pressure medium via the first (early) retard chamber is supplied from the volume memory.
Each of the pressure medium channels is associated with a check valve, wherein each of the check valves prevents a pressure medium flow from the associated pressure chamber to the volume memory and a reverse pressure medium flow, with a suitable pressure difference upstream and downstream of the check valve permits. The check valves can be arranged, for example, within the pressure medium channel and designed, for example, as a ball or plate check valve. Likewise conceivable are embodiments in which a spring plate cooperates with an opening region of the associated pressure medium channel in the manner of a check valve. The volume accumulator can communicate via one or more pressure medium lines with a pressure medium reservoir of the internal combustion engine or be connectable.
The phase angle of the camshaft relative to the crankshaft can be varied or held with this device on the one hand by the system pressure provided by the pressure medium pump of the internal combustion engine. To the Others can be used to change the moment acting on the camshaft to bring about a phase adjustment. In this case, the proportion of the alternating torque acting against the adjustment direction is intercepted and the proportion acting in the adjustment direction is utilized in order to increase the phase adjustment speed. The amount of the component of the alternating torque, which is to be used for phase adjustment, increases continuously in dependence on the rotational position of the camshaft from 0 to a maximum value and falls back to zero. In this case, the output element is rotated relative to the drive element in the direction of the desired phase position. As a result, the pressure increases rapidly in the pressure chambers to be emptied, whereby the emptying of the pressure chambers is accelerated. On the other hand, the pressure medium requirement of the pressure chambers to be filled increases to the same extent. At a small acting moment, the pressure medium requirement of the pressure chambers to be filled can be supplied by the pressure medium pump. In this case, it can be provided that the pressure fluid flowing out of the pressure chambers to be emptied fills the volume reservoir (s). As the moment increases, the pressure medium requirement of the pressure chambers to be filled increases, which can lead to the fact that the volume flow delivered by the pressure medium pump is insufficient to completely fill the pressure chambers to be filled. Thus arises in the pressure chambers to be filled a negative pressure, which has a braking effect on the adjustment speed in conventional devices. In the apparatus according to the invention, the pressure medium stored in the volume memory (s) can be used in these phases to fill the pressure chambers by the pressure accumulator (s) and the pressure medium channels provided. Due to the pressure difference between the pressure chambers and the volume or the accumulators open the check valves in the pressure medium channels to the pressure chambers to be filled, so that pressure medium can get into it. As a result of the additional pressure medium volume which is provided in the volume accumulator (s) and fed to the pressure chambers to be filled during these phases, the phase adjustment speed can be increased considerably in comparison to devices which are operated exclusively by the system pressure provided by the pressure medium pump.
In devices in which the alternating moments are utilized to adjust the phase angle of the camshaft relative to the crankshaft, the pressure medium, which is ejected from the pressure chambers to be emptied, passed directly and under high pressure to the pressure chambers to be filled. In this case, only a part of the pressure medium volume ejected from the pressure chambers reaches the pressure chambers to be filled. Another part is lost due to leakage. In some embodiments, losses also result from the pressure medium being returned to a control valve, whereby a part of the pressure medium is expelled into a pressure medium reservoir of the internal combustion engine and thus can no longer reach the pressure chambers to be filled.
Thus, in these embodiments, sufficient pressure medium for filling the expanding pressure chambers is not available, so that again a negative pressure occurs in these pressure chambers, which has a negative effect on the Phasenverstellgeschwindigkeit. With a suitable design of the volume memory of the proposed device, this loss is compensated by the pressure medium volume provided in the volume memory (s) and thus the phase adjustment speed is increased. In addition, the pressure medium is not passed under high alternating torques under the high pressure generated by these high pressure in the pressure chambers. Rather, the vacuum occurring in the pressure chambers to be filled is utilized to forward the pressure medium from the volume or the accumulators in the pressure chambers. Thus, no sudden phase changes occur, whereby the controllability of the device is maintained.

In an advantageous development of the invention it is provided that the volume memory is arranged within the phase adjusting device. Thus, the stored pressure medium is in local proximity to the pressure chambers. Thus, pressure medium losses between volume memory and pressure chambers are lowered and the response of the device improved.
It can be provided that the volume accumulator is connectable via one or more pressure medium lines with a pressure medium reservoir, wherein the mouth region of the pressure medium channels in the volume memory with larger Distance from the axis of rotation of the phase adjusting device is arranged as the mouth region of the pressure medium lines in the volume memory. This ensures that excess pressure medium can be removed from the volume accumulator to the pressure medium reservoir of the internal combustion engine. Since the phase adjusting device rotates about its axis of rotation is ensured due to the centrifugal force that still pending at the mouth areas of the pressure medium channels in the volume or the pressure medium for further transport to the pressure chambers.
In the event that the one or more volume memory communicate or connected to a pressure medium reservoir, it can be provided that the one or more pressure medium lines which connect the volume memory with the pressure medium reservoir, a check valve is assigned, which prevents a pressure medium flow from the pressure medium reservoir to the volume memory and allow a reverse pressure medium flow. If this check valve is dispensed with, the pressure in the pressure medium reservoir, as a rule atmospheric pressure, prevails in the volume reservoirs. By the check valve, the pressure level of the stored pressure medium can be raised, whereby the support of the phase adjustment by the volume or the memory starts even at smaller alternating torques.
The volume or the accumulator pressure medium can be supplied directly from a pressure medium pump. In this case, for example, branch off a pressure medium line directly from the engine oil gallery and open, bypassing the pressure chambers in the volume memory. For example, the pressure medium via a control valve, which controls the pressure medium flow to and from the pressure chambers, reach the volume or the stores. This ensures that the volume accumulator is adequately supplied with pressure medium at all times. Alternatively, pressure medium can be supplied to the volume accumulator from the pressure chambers. With each phase adjustment, one group of pressure chambers expands at the expense of the other pressure chambers. The pressure fluid flowing out of the other pressure chambers can be supplied to the volume accumulator (s) and reused, as a result of which the delivery flow of the pressure medium pump can be lowered. The pressure medium ejected from the pressure chambers can, for example, via a control valve, which controls the pressure medium flows from and to the pressure chambers, are directed to the or the volume memory.

In one embodiment of the invention, it is provided that the device has a control valve, by means of which the pressure medium supply can be controlled by a pressure medium pump to the pressure chambers and the pressure medium discharge from the pressure chambers.
In a concretization of the invention it is provided that the control valve has an inlet port, a first and a second working port and at least a first volume storage port, wherein a first pressure medium line is provided which communicates on the one hand with the first working port and on the other hand into the advance chamber, wherein a second pressure medium line is provided which communicates on the one hand with the second working port and on the other hand into the retardation, wherein a third pressure medium line is provided which communicates on the one hand with the inlet port and on the other hand with a pressure medium pump, wherein at least a fourth pressure medium line is provided, on the one hand with the Volumenspeicheranschluss communicates and on the other hand opens into the volume memory and wherein by means of the control valve, a connection between the inlet port and the first and the second working port and ei ne connection between the volume storage port and the other work connection can be made.
In an alternative embodiment, it is provided that the control valve has an inlet connection, a first and a second working connection, two volume storage connections and a discharge connection, wherein a first pressure medium line is provided which communicates with the first working connection on the one hand and opens into the advance chamber on the other hand second pressure medium line is provided which communicates on the one hand with the second working port and on the other hand into the retardation, wherein a third pressure medium line is provided which communicates on the one hand with the inlet port and on the other hand with a pressure medium pump, wherein two fourth pressure medium lines are provided, on the one hand in the volume memory and on the other hand with one each communicate the volume storage ports, with a fifth pressure medium line provided, which communicates on the one hand with the drain port and the other with a pressure medium reservoir, wherein by means of the control valve, a connection between the inlet port and the first and the second working port, a connection between one of the volume storage ports and the other working port and a connection between the other volume storage port and the drain port can be made.

Thus, the pressure fluid flows to be filled to the pressure chambers and the pressure fluid outflows are controlled by the pressure chambers to be emptied via a control valve which simultaneously controls the filling of the volume or the memory from the pressure chambers to be emptied. The pressure medium flows are conducted via control edges within the control valve and can be influenced by the design of existing between the control edges flow areas. Thus, the device can operate both in a mode in which the phase adjustment is effected by the system pressure generated by the pressure medium pump and in a mode in which the change moment is used for phase adjustment. In this case, the change from one to the other mode takes place automatically in that the delivery volume of the pressure medium pump no longer covers or recovers the pressure medium requirement of the pressure chambers to be filled. Furthermore, the phase adjustment can be controlled by means of a sequence control, ie the adjustment speed is determined by the amount of pressure flowing from the pressure chambers and not by the amount of the pressure chambers to be filled pressure medium. This can be realized in a simple manner in that a flow area of the pressure chambers to the volume or the accumulator or the pressure medium reservoir is always designed smaller than a flow area of the pressure medium pump to the pressure chambers. This prevents air from being sucked into the pressure chambers. In addition, the pressure medium flow to and from the pressure chambers in response to a control parameter of the control valve does not increase abruptly, so that a simple and stable control of the device is ensured.

The pressure medium channels which connect the volume or the storage with the pressure chambers, for example, open directly into the corresponding pressure chambers or in the pressure medium lines that connect the working ports of the control valve with the pressure chambers.

Brief description of the drawings

Figur 1

nur sehr schematisch eine Brennkraftmaschine,

Figur 2

eine erste Ausführungsform einer erfindungsgemäßen Vorrichtung im Längsschnitt,

Figur 3

einen Draufsicht auf die Phasenstelleinrichtung aus Figur 2 ent-lang des Pfeils III,

Figur 4

eine schematische Darstellung der Vorrichtung aus Figur 2,

Figur 5, 6

jeweils eine vergrößerte Darstellung der Einzelheit Z aus Figur 2,

Figur 7, 8

eine zweite Ausführungsform einer erfindungsgemäßen Vorrich-tung analog der Darstellung der Figuren 5, 6,

Figur 9

eine schematische Darstellung einer dritten erfindungsgemäßen Vorrichtung analog der Darstellung der Figur 4,

Figur 10, 11

eine Darstellung der dritten Ausführungsform einer Vorrichtung analog der Darstellung der Figuren 5, 6.

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

FIG. 1

only very schematically an internal combustion engine,

FIG. 2

a first embodiment of a device according to the invention in longitudinal section,

FIG. 3

a plan view of the phase adjusting device FIG. 2 ent-long of the arrow III,

FIG. 4

a schematic representation of the device FIG. 2 .

FIG. 5, 6

each an enlarged view of the detail Z from FIG. 2 .

FIG. 7, 8

a second embodiment of a Vorrich device according to the invention analogous to the representation of FIGS. 5, 6 .

FIG. 9

a schematic representation of a third device according to the invention analogous to the representation of FIG. 4 .

FIG. 10, 11

a representation of the third embodiment of a device analogous to the representation of FIGS. 5, 6 ,

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 11 for variably setting the timing of gas exchange valves 9,10 an internal combustion engine 1 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 inlet gas exchange valves 9 or one or more Auslassgaswechselventile 10. Likewise, it may be provided only one of the camshafts 6, 7 with a device 11, or provide only a camshaft 6, 7, which with a Device 11 is provided.

FIG. 2 shows a first embodiment of a device 11 according to the invention in longitudinal section. FIG. 3 shows a plan view of a phase adjusting device 12 of the device 11, wherein the arranged in the line of sight side cover 17 has been omitted.
The device 11 has a phase adjusting device 12 and a control valve 13. The phase adjusting device 12 has a drive element 15 and an output element 16. On an outer circumferential surface of the drive element 15, a sprocket 14 is arranged, by means of which a torque can be transmitted from the crankshaft 2 to the drive element 15 via a chain drive, not shown. On the axial side surfaces of the drive element 15 each have a side cover 17 is rotatably attached.
The output element 16 is designed in the form of an impeller and has a substantially cylindrical hub member 18, extend from the outer cylindrical surface in the illustrated embodiment, two wings 19 in the radial direction outwards and are integrally formed with the hub member 18. A central passage opening of the output element 16 is penetrated by a hollow camshaft 6, 7, wherein the output element 16 by means of a press fit with the Camshaft 6, 7 is rotatably connected.

Starting from a peripheral wall 20 of the drive element 15, four projections 21 extend radially inwards. In the illustrated embodiment, the projections 21 are formed integrally with the peripheral wall 20. The drive element 15 is mounted by means of radially inner circumferential walls of the projections 21 relative to the output member 16 rotatably mounted on this.

Within the phase adjusting device 12, a pressure medium chamber 22 is formed between each two circumferentially adjacent projections 21. Each of the pressure medium spaces 22 is circumferentially bounded by opposing, substantially radially extending boundary walls 23 of adjacent projections 21, in the axial direction of the side covers 17, radially inwardly of the hub member 18 and radially outwardly of the peripheral wall 20. In each case one wing 19 projects in two of the four pressure medium spaces 22, wherein the wings 19 are designed in such a way that they rest against both the side covers 17 and the peripheral wall 20. Each wing 19 thus divides the respective pressure medium chamber 22 into two counteracting pressure chambers 24, 25, an advance chamber 24 and a retard 25. The other two pressure medium spaces 22, which are not divided by a wing 19 in pressure chambers 24, 25, serve as a volume memory 31st Each of the pressure chambers 24, 25 communicates with one of the volume accumulators 31 via a pressure medium channel 32a, b formed in the projections 21. A first pressure medium channel 32a connects a volume accumulator 31 with an advance chamber 24 and a respective second pressure medium channel 32b with a volume accumulator 31 a late adjustment 25. Each fluid channel 32a, b is associated with a first check valve 33, which prevents a flow of pressure medium from the respective pressure chamber 24, 25 to the respective volume memory 31 and a pressure medium flow from the volume memory 31 to the respective pressure chamber 24, 25 permits, as soon as de Finished pressure difference between the pressure chamber 24, 25 and the volume memory 31 prevails. The first check valves 33 can be arranged, for example, within the pressure medium channels 32a, b and as ball check valves be educated.

The output member 16 is received in the drive member 15 and rotatably supported within a defined Winkelbreichs to this. The angular range is limited in one direction of rotation of the driven element 16 in that the wings 19 come into contact with a corresponding boundary wall 23 (early stop 23a) of the associated pressure medium spaces 22. Similarly, the angular range in the other direction of rotation is limited by the fact that the wings 19 come to rest on the other boundary walls 23 of the associated pressure medium spaces 22, which serve as a late stop 23b.

By pressurizing the Frühverstellkammern 24 with simultaneous outflow of pressure medium from the retard adjustment 25, the phase angle of the output element 16 can be adjusted relative to the drive element 15 in the direction of earlier control times. In this case, the output element 16 is rotated in the direction of rotation of the device 11, characterized by the arrow 29, relative to the drive element 15.
By applying pressure to the late adjustment chambers 25 with simultaneous outflow of pressure medium from the advance chambers 24, the phase position of the output element 16 can be adjusted relative to the drive element 15 in the direction of later control times. In this case, the output element 16 is rotated counter to the direction of rotation 29 of the device 11 relative to the drive element 15.
By pressurizing both groups of pressure chambers 24, 25, the phase position can be kept constant. Alternatively it can be provided to pressurize none of the pressure chambers 24, 25 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.

The pressure medium supply to or pressure fluid removal from the pressure chambers 24, 25 via a hydraulic circuit, the in FIG. 4 is shown and controlled by means of the control valve 13. The control valve 13 has an inlet connection P, a volume storage port V ₁ and two working ports A, B on. The hydraulic circuit has five pressure medium lines 26a, b, p, v, t. The first pressure medium line 26a communicates on the one hand with the first working port A and on the other hand flows into the advance chambers 24. The second pressure medium line 26b communicates on the one hand with the second working port B and on the other hand flows into the retardation chambers 25. The third pressure medium line 26p connects a pressure medium pump 27 with the inlet port P. wherein a second check valve 34 prevents a pressure medium flow from the control valve 13 to the pressure medium pump 27 and can allow a reverse pressure medium flow. The fifth pressure medium line 26v communicates on the one hand with the volume storage port V ₁ and on the other hand flows into the volume accumulator 31. The fifth pressure medium line 26t opens on the one hand in the volume accumulators 31 and on the other hand in a pressure medium reservoir 28, for example an oil sump of the internal combustion engine 1. The fifth pressure medium line can directly Pressure medium reservoir 28 open (solid line in FIG. 4 ) or with the interposition of a third check valve 50 (dashed line in FIG. 4 ).
The control valve 13 can assume three control positions S1-S3. In the first control position S1, the inlet connection P is connected to the first working connection A and the second working connection B is connected to the volume storage connection V ₁ . In the second control position S2, there is no connection between the working ports A, B on the one side and the inlet port P and the volume storage port V ₁ on the other side. In the third control position S3, the inlet connection P is connected to the second working connection B and the first working connection A is connected to the volume storage connection V ₁ .

During operation of the internal combustion engine 1, the camshaft 6, 7 rotates about its longitudinal axis. In this case, each gas exchange valve 9, 10 by means of a cam 8 periodically against the force of a valve spring 30 (FIG. FIG. 1 ) opened and closed again. During the opening phase of the gas exchange valve 9, 10 (auflaufender cam 8) acts on the camshaft 6, 7 a braking torque, which is the vector product of the force of the valve spring 30 with the Lever arm of the cam 8 corresponds. During the closing of the gas exchange valve 9, 10 (expiring cam) acts on the camshaft 6, 7 an accelerating torque, which corresponds to the vector product of the force of the valve spring 30 with the lever arm of the cam 8. Thus acts on the camshaft 6, 7, a periodic alternating torque. The alternating moment causes the wings 19 to be urged counter to the direction of rotation 29 of the phase adjusting device 12 when the cam 8 runs up. As a result, the pressure in the advance chambers 24 is increased and the pressure in the retard chambers 25 is lowered. When running cam 8, the wings 19 are urged in the direction of rotation 29 of the phase adjusting device 12, whereby the pressure in the Frühverstellkammern 24 decreases and the pressure in the retard 25 increases.

During operation of the internal combustion engine 1, two states can now occur. In a first operating state, the system pressure generated by the pressure medium pump 27 within the hydraulic circuit exceeds the pressure which is generated in the pressure chambers 24, 25 by the alternating torques acting on the camshaft 6, 7. In a second operating state, the pressure peaks generated in the pressure chambers 24, 25 by the alternating moments exceed the system pressure provided by the pressure medium pump 27.

If a phase adjustment is requested in the direction of earlier control times, the control valve 13 assumes the first control position S1. In operating phases in which the operating pressure conveyed by the pressure medium pump 27 exceeds the pressure level generated by the alternating moment in the pressure chambers 24, 25, the pressure medium conveyed by the pressure medium pump 27 reaches via the third pressure medium line 26p, the inlet port P, the first working port A and the First pressure medium line 26a to the advance chambers 24. As a result, the wings 19 are moved within the respective pressure medium spaces 22 in the direction of rotation 29 of the phase adjusting device 12. At the same time pressure medium from the retardation chambers 25 via the second pressure medium line 26b, the second working port B, the volume storage port V ₁ and the fourth pressure medium line 26v is forced into the volume memory 31. Thus, the volume of the 31 crowded. Thus, the volume of Frühverstellkammern 24 increases at the expense of Spätverstellkammern 25 and the wings 19 are moved in the direction of rotation 29 of the phase adjusting device 12. As a result, the camshaft 6, 7 is rotated in the direction of earlier control times relative to the crankshaft 2. The volume accumulators 31 are filled by the pressure medium flowing out of the retard chambers 25, excess pressure medium being expelled via the fifth pressure medium line 26t into the pressure medium reservoir 28 against atmospheric pressure or the third nonreturn valve 50. Thus, a higher pressure level prevails both in the advance chambers 24 and in the retard adjustment chambers 25 than in the volume accumulators 31, whereby the first check valves 33 prevent a pressure medium flow from the volume accumulators 31 into the pressure chambers 24, 25.

In operating phases in which the pressure level generated by the alternating moment in the pressure chambers 24, 25 exceeds the operating pressure delivered by the pressure medium pump 27, two cases have to be distinguished: a supporting moment acting in the adjustment direction and a moment acting counter to the adjustment direction.
In the case of a supporting moment, the camshaft 6, 7 is accelerated and thus the wings 19 are moved in the direction of the early stop 23a. This results in a pressure drop in the advance chambers 24 and an increase in the pressure in the retard 25. Thus prevails in the retard 25 higher pressure than in the advance chambers 24, wherein the pressure in the advance chambers 24 may fall below the atmospheric pressure. Pressure medium is thus supplied to the volume accumulators 31 from the retard adjustment chambers 25 via the second pressure medium line 26b, the second working port B, the volume storage port V ₁ and the fourth pressure medium line 26v. In the volume accumulators 31 prevails due to the opening into the pressure medium reservoir 28 fifth pressure medium line 26t atmospheric pressure, or in embodiments in which a third check valve 50 is provided in the fifth pressure medium line 26t, defined by the third check valve 50 higher pressure level, but which less than the pressure level within the retard chambers 25 is. Due to the higher pressure levels in the retard chambers 25 block the first check valves 33, which connect the volume memory 31 with the retard 25, a pressure medium flow from the volume accumulators 31 in the retard 25 simultaneously arrives pressure medium from the pressure medium pump 27 via the inlet port P, the first When the pressure medium requirement of the pressure chambers 24 to be filled exceeds the volume flow delivered by the pressure medium pump 27, the pressure in the advance chambers 24 drops below the pressure prevailing in the volume accumulators 31. Thus, the first check valves 33 release a pressure medium flow through the first pressure medium channels 32 a from the volume stores 31 to the advance chambers 24. Since the mouth points of the pressure medium channels 32a, b in the volume memory 31 in the radial direction a greater distance from the axis of rotation of the phase adjusting device 12 than the mouth points of the fifth pressure medium line 26t, is ensured due to the centrifugal forces prevailing in the rotating device 11 that no air in the Frühverstellkammern 24 is sucked. During this process, the volume accumulators 31 are continuously refilled by the pressure medium flowing out of the retard chambers 25. Thus, the advance is assisted at a supportive acting moment compared to conventional devices 11 by a stored in the volume memory 31 pressure medium volume. Compared to devices 11, in which the pressure medium emerging from the retardation chamber 25 is conducted to the inlet connection P of the control valve 13 and from there to the advance chambers 24, the advantage is that leakage losses are compensated and even overcompensated by the pressure medium volume already contained in the volume accumulators 31 become. Thus, the Phasenverstellgeschwindigkeit is reliably increased.

In the case of a torque acting against the adjustment direction, a braking moment acts on the camshaft 6, 7, as a result of which the wings 19 are urged in the direction of the late stop 23b. Thus, the pressure in the advance chambers 24 increases, the pressure means through the second check valve 34 and the first check valves 33 is prevented from exiting the Frühverstellkammern 24. As a result, the wings 19 are held in their position, whereby the pressure in the retardation chambers 25 does not drop and thus does not fall below the pressure prevailing in the volume accumulators 31 pressure. Thus, the first check valves 33 prevent a flow of pressure medium from the volume accumulators 31 to the retard chambers 25. Consequently, in a direction opposite to the Phasenverstellrichtung moment no turning back of the device 11, but the current phase position is maintained.

If a phase adjustment is requested in the direction of later control times, the control valve 13 assumes the third control position S3. In operating phases in which the operating pressure delivered by the pressure medium pump 27 exceeds the pressure level generated by the alternating moment in the pressure chambers 24, 25, the pressure medium conveyed by the pressure medium pump 27 reaches the third pressure medium line 26p, the inlet port P, the second working port B and the second pressure medium line 26b to the retarding 25. As a result, the wings 19 are moved within the respective pressure medium spaces 22 against the direction of rotation 29 of the phase adjusting device 12. At the same time pressure medium from the Frühverstellkammern 24 via the first pressure medium line 26a, the first working port A, the volume storage port V ₁ and the fourth pressure medium line 26v is forced into the volume memory 31. Thus, the volume of the retard chambers 25 increases at the expense of the advance chambers 24 and the wings 19 are displaced counter to the direction of rotation 29 of the phase adjuster 12. As a result, the camshaft 6, 7 is rotated in the direction of later control times relative to the crankshaft 2. The volume memory 31 are filled by the running out of the advance chambers 24 pressure medium, wherein excess pressure medium via the fifth pressure medium line 26t in the pressure medium reservoir 28 against atmospheric pressure or the third check valve 50 is ejected. Thus, a higher pressure level prevails both in the advance chambers 24 and in the retard adjustment chambers 25 than in the volume accumulators 31, whereby the first check valves 33 prevent a pressure medium flow from the volume accumulators 31 into the pressure chambers 24, 25.

In operating phases in which the pressure level generated by the alternating moment in the pressure chambers 24, 25 exceeds the operating pressure delivered by the pressure medium pump 27, a distinction must again be made between an assisting moment acting in the adjustment direction and a moment acting counter to the adjustment direction.
In the case of a supporting torque, the camshaft 6, 7 is braked and thus the wings 19 are moved in the direction of the late stop 23a. This results in a pressure reduction in the retardation chambers 25 and an increase in the pressure in the advance chambers 24. Thus prevails in the Frühverstellkammern 24, a higher pressure than in the retardation 25, wherein the pressure in the retard 25 can fall below the atmospheric pressure. Pressure medium is thus supplied from the advance chambers 24 via the first pressure medium line 26a, the first working port A, the volume storage port V ₁ and the fourth pressure medium line 26v the volume accumulators 31. In the volume accumulators 31 prevails due to the opening into the pressure medium reservoir 28 fifth pressure medium line 26t atmospheric pressure or in embodiments in which a third check valve 50 is provided in the fifth pressure medium line 26t, defined by the third check valve 50 higher pressure level, but which lower as the pressure level within the retard chambers 25. Due to the higher pressure level in the advance chambers 24, the first check valves 33, which connect the volume accumulators 31 to the advancing chambers 24, block a flow of pressure medium from the volume accumulators 31 into the advancing chambers 24.
At the same time, pressure medium from the pressure medium pump 27 passes via the inlet connection P, the second working connection B and the second pressure medium line 26b to the retard chambers 25. If the pressure medium requirement of the pressure chambers 25 to be filled exceeds the volume flow delivered by the pressure medium pump 27, the pressure in the retard adjustment chambers 25 drops under the pressure prevailing in the volume accumulators 31 pressure. Thus, the first check valves 33 release a pressure medium flow through the second pressure medium channels 32 b from the volume stores 31 to the retard chambers 25. Because the Muzzle points of the pressure medium channels 32a, b in the volume memory 31 in the radial direction a greater distance from the axis of rotation of the phase adjusting device 12 than the mouth points of the fifth pressure medium line 26t, is ensured on the basis of prevailing in the rotating device 11 centrifugal forces that no air in the retard 25 is sucked. During this process, the volume accumulators 31 are continuously refilled by the pressure medium flowing out of the retard chambers 25.
Thus, the retardation is supported at a supportive acting moment in comparison to conventional devices 11 by a stored in the volume memory 31 pressure medium volume. Compared with devices 11 in which the pressure medium emerging from the advance chamber 24 is directed to the inlet connection P of the control valve 13 and from there to the retardation chambers 25, the advantage is that leakage losses are compensated and even overcompensated by the pressure medium volume already contained in the volume accumulators 31 become. Thus, the Phasenverstellgeschwindigkeit is reliably increased.

In the case of a torque acting against the adjustment direction, the camshaft 6, 7 is accelerated and thus the wings 19 are urged in the direction of the early stop 23a. Thus, the pressure in the retardation chambers 25 increases, the pressure medium being prevented from exiting the retard chambers 25 by the second check valve 34 and the first check valves 33. Characterized the wing 19 is held in its position, whereby the pressure in the Frühverstellkammern 24 does not drop and thus does not fall below the pressure prevailing in the volume accumulators 31 pressure. Thus, the first check valves 33 prevent fluid flow from the volume accumulators 31 to the advance chambers 24. Consequently, in a reverse phase shift direction, there is no reverse rotation of the device 11, but the current phase position is maintained.

If the current phase position is to be maintained, the control valve 13 assumes the second control position S2. In this control position are the working connections Completed. Thus, the pressure medium conveyed from the pressure medium pump 27 to the inlet port P does not reach any of the working ports A, B. Likewise, no pressure fluid from the pressure chambers 24, 25 reaches the volume memory port V ₁ . Upon the occurrence of pressure peaks in the pressure chambers 24, 25, which are caused by the acting on the camshaft 6, 7 alternating torque, an outlet of pressure medium from the pressure chambers 24, 25 prevented by the closed working ports A, B. The wings 19 are thus hydraulically clamped between the pressure chambers 24, 25, whereby the current phase position is maintained. At the same time, it is ensured that the pressure prevailing in the pressure chambers 24, 25 exceeds the pressure prevailing in the volume accumulators 31, whereby a flow of pressure medium from the volume accumulators 31 via the pressure medium channels 32a, b into the pressure chambers 24, 25 is prevented.

The FIGS. 5 and 6 show the detail Z out FIG. 2 in an enlarged view, wherein the control valve 13 in the first ( FIG. 5 ) or third control position S3 ( FIG. 6 ) is shown. The first and the second pressure medium line 26a, b are formed as axial staggered radial bores within the output element 16. In this embodiment, two fourth pressure medium lines 26v are provided, which are likewise designed as axially offset radial bores within the output element 16. The first, the second and the fourth pressure medium lines 26a, b, v are arranged offset to one another in the circumferential direction of the output element 16 (see FIG. 3 ), in the FIGS. 5 and 6 but shown in a single level for better explanation. The first, second and fourth pressure medium lines 26a, b, v open on the one hand into the advance chambers 24 and the retard chambers 25 and the volume reservoirs 31. The other ends of the pressure medium lines 26a, b, v open into radial bores of the camshaft 6, 7, in turn communicate with the first working port A and the second working port B and two volume accumulator ports V _{1 of} the control valve 13, which are formed on a valve housing 36 of the control valve 13 as radial openings 37. Within the valve housing 36, a control piston 38 is arranged, which by means of an actuating unit, not shown against the force of a spring 39 in the axial direction within the a spring 39 in the axial direction within the valve housing 36 can be moved. In this case, the control piston 38 in each position between the in FIG. 5 and the in FIG. 6 shifted position shown and held.

Is the control valve 13 in the first control position S1 ( FIG. 5 ), so enters via the inlet port P pressure fluid into the interior of the valve housing 36 and further into the interior of the control piston 38 a. From there, the pressure medium passes through a piston opening 40 to the first working port A. In this case, the pressure medium passes through a first control surface 41, which is defined by the overlap of the piston opening 40 with the radial opening 37 of the first working port A. At the same time, pressure medium from the late adjustment chambers 25 reaches the second working connection B via the second pressure medium line 26b. The latter is connected to the outer lateral surface of the control piston via a first annular groove 42 38 is formed, with the volume storage port V ₁ in conjunction. On the way from the second working port B to the volume storage port V ₁ , the pressure medium passes through a second control surface 43, which is defined by the overlap of the radial opening 37 of the second working port B with the first annular groove 42. In the illustrated embodiment, the second control surface 43 is made smaller than the first control surface 41 (flow control). Thus, the outflow from the retard chambers 25 is throttled with respect to the inflow to the Frühverstellkammern 24, which ensures that the pressure chambers 24, 25 are always completely filled during operation of the internal combustion engine 1.
The first control position S1 can be realized by a plurality of positions of the control piston 38 relative to the valve housing 36. In this case, the control piston 38 must be in a position in which pressure medium from the inlet port P to the first working port A and pressure medium from the second working port B can reach the volume storage port V ₁ . In this case, the first and second control surfaces 41, 43 and, analogously, the pressure medium flow to and from the pressure chambers 24, 25 are greater the further the control piston 38 in the FIG. 5 approaching position shown.

Is the control valve 13 in the third control position S3 ( FIG. 6 ), so enters via the inlet port P pressure fluid into the interior of the valve housing 36 and further into the interior of the control piston 38 a. From there, the pressure medium passes through the piston opening 40 to the second working port B. The pressure medium passes through a third control surface 44, which is defined by the overlap of the piston opening 40 with the radial opening 37 of the second working port B. At the same time, pressure medium from the advance chambers 24 passes via the first pressure medium line 26a to the first working port A. This is connected via a second annular groove 45, which on the outer circumferential surface of the control piston 38 is formed, with the volume storage port V ₁ in conjunction. On the way from the first working port B to the volume storage port V ₁ , the pressure medium passes through a fourth control surface 46, which is defined by the overlap of the radial opening 37 of the first working port A with the second annular groove 45. In the illustrated embodiment, the fourth control surface 46 is made smaller than the third control surface 44 (process control). Thus, the outflow from the advance chambers 24 is throttled with respect to the inflow to the retard chambers 25, which ensures that the pressure chambers 24, 25 are always completely filled during operation of the internal combustion engine 1.
The third control position S3 can be realized by a plurality of positions of the control piston 38 relative to the valve housing 36. In this case, the control piston 38 must be in a position in which pressure medium can pass from the inlet connection P to the second working connection B and pressure medium from the first working connection A to the volume storage connection V ₁ . In this case, the third and the fourth control surface 44, 46 and analogously to the flow of pressure medium to and from the pressure chambers 24, 25, the greater the further the control piston 38 in the FIG. 6 approaching position shown.

The FIGS. 7 and 8 show a second embodiment analogous to the illustrations of FIGS. 5 and 6 , This embodiment is largely identical to the first embodiment, so that in the following only the differences will be discussed. In the second embodiment, only a fourth pressure medium line is 26v provided which communicates on the one hand with the volume accumulators 31 and on the other hand with the single volume memory port _V1. The fourth pressure medium line 26v is arranged in the axial direction between the first and second pressure medium line 26a, b.

The control piston 38 has two piston openings 40, 47 and an annular groove 42 on its outer circumferential surface, wherein the piston openings 40, 47 and the annular groove 42 are arranged spaced from each other in the axial direction. In this case, the annular groove 42 is arranged between the piston openings 40, 47.
Is the control valve 13 in the first control position S1 ( FIG. 7 ), so enters via the inlet port P pressure fluid into the interior of the valve housing 36 and further into the interior of the control piston 38 a. From there, the pressure medium passes via the first piston opening 40 to the first working port A. The pressure medium passes through a first control surface 41, which is defined by the overlap of the first piston opening 40 with the radial opening 37 of the first working port A. At the same time, pressure medium from the late adjustment chambers 25 reaches the second working connection B via the second pressure medium line 26b. The latter communicates via the annular groove 42 with the volume storage connection V ₁ , On the way from the second working port B to the volume storage port V ₁ , the pressure medium passes through a second control surface 43, which is defined by the overlap of the radial opening 37 of the second working port B with the annular groove 42. In the illustrated embodiment, the second control surface 43 is made smaller than the first control surface 41 (flow control). Thus, the outflow from the retardation chambers 25 is throttled with respect to the inflow to the advance chambers 24, whereby it is ensured that the pressure chambers 24, 25 are always completely filled during operation of the internal combustion engine 1.

Is the control valve 13 in the third control position S3 ( FIG. 8 ), so enters via the inlet port P pressure fluid into the interior of the valve housing 36 and further into the interior of the control piston 38 a. From there, the pressure medium passes via the second piston opening 47 to the second working port B. The pressure medium passes through a third control surface 44, which is defined by the overlap of the second piston opening 47 with the radial opening 37 of the second working port B. At the same time, pressure medium from the advance chambers 24 reaches the first working port A via the first pressure medium line 26a. The latter communicates via the annular groove 42 with the volume storage port V ₁ . On the way from the first working port A to the volume storage port V ₁ , the pressure medium passes through a fourth control surface 46, which is defined by the overlap of the radial opening 37 of the first working port A with the annular groove 42. In the illustrated embodiment, the fourth control surface 46 is made smaller than the third control surface 44 (process control). Thus, the outflow from the advance chambers 24 is throttled with respect to the inflow to the retard chambers 25, which ensures that the pressure chambers 24, 25 are always completely filled during operation of the internal combustion engine 1.

FIG. 9 shows a further embodiment of a device 11 according to the invention. The third embodiment is designed in many parts identical to the first two embodiments, so that in the following only the deviations are explained. In contrast to the first two embodiments, the control valve 13 has two volume storage ports V ₁ , V ₂ and an additional drain port T. Both volume storage ports V ₁ , V ₂ are connected via a respective fourth pressure medium line 26 v to the volume reservoirs 31. The outlet connection T is connected to the pressure medium reservoir 28 by means of the fifth pressure medium line 26t.

The control valve 13 can in turn assume three control positions S1-S3. In the first control position S1, the inlet connection P to the first working port A, the second working port B to the second volume storage port V ₂ and the first volume storage port V ₁ to the drain port T is connected. In the second control position S2, there is no connection between the working ports A, B on the one side and the inflow port P and the volume accumulator ports V ₁ , V ₂ on the other side. In the third control position S3, the inlet connection P is connected to the second working connection B, the first working connection A to the first volume storage connection V ₁ and the second volume storage connection V ₂ to the discharge connection T.
The FIGS. 10 and 11 show the control valve 13 of the third embodiment and the associated pressure medium lines 26a, b, v, t.
The first, the second and the two fourth pressure medium line 26a, b, v are in turn formed as axially offset from one another, radial bores within the output element 16. The first and second pressure medium line 26a, b in turn open into the corresponding pressure chambers 24, 25 and are connected to the working ports A, B. The fourth pressure medium lines 26v open into the volume memory 31 and are each connected to one of the volume storage ports V ₁ , V ₂ . The fifth pressure medium line 26t is realized as a radial opening 37 in the camshaft 6, 7 and communicates with the discharge port T and the pressure medium reservoir 28. Within the valve housing 36, in turn, a positionable in the axial direction to the valve housing 36 control piston 38 is arranged. The control piston 38 is provided with a radial piston opening 40, which is arranged between two annular grooves 42, 45 formed on the outer circumferential surface of the control piston 38.
Is the control valve 13 in the first control position S1 ( FIG. 10 ), so enters via the inlet port P pressure fluid into the interior of the valve housing 36 and further into the interior of the control piston 38 a. From there, the pressure medium passes through the piston opening 40 to the first working port A. In this case, the pressure medium passes through a first control surface 41, which by the overlap of the piston opening 40 with the radial opening 37 of the first working port A is defined. At the same time, pressure medium from the retardation chambers 25 reaches the second working connection B via the second pressure medium line 26b. The latter is connected to the second volume storage connection V ₂ via a second annular groove 45 Connection. On the way from the second working port B to the second volume storage port V ₂ , the pressure medium passes through a second control surface 43 which is defined by the overlap of the radial opening 37 of the second working port B with the second annular groove 45. If the volume accumulators 31 are completely filled, pressure medium from the volume accumulators 31 passes via the fourth pressure medium line 26v to the first volume accumulator connection V ₁ , which is connected to the outlet connection T via the first annular groove 42. In this case, the pressure medium passes through a third control surface 44, which is defined by the overlap of the radial opening 37 of the first volume storage port V ₁ with the first annular groove 42. In the illustrated embodiment, the third control surface 44 is smaller than the second control surface 43 and made smaller than the first control surface 41. Thus, the outflow from the late adjustment chambers 25 is throttled with respect to the inflow to the advance chambers 24 and thus a flow control realized in this embodiment. At the same time, the feed to the volume accumulators 31 is throttled in comparison to the first two embodiments, whereby the pressure medium enters under higher pressure in this.

Is the control valve 13 in the third control position S3 ( FIG. 11 ), so enters via the inlet port P pressure fluid into the interior of the valve housing 36 and further into the interior of the control piston 38 a. From there, the pressure medium passes through the piston opening 40 to the second working port B. The pressure medium passes through a fourth control surface 46, which is defined by the overlap of the piston opening 40 with the radial opening 37 of the second working port B. From the second working port B, the pressure medium passes through the second pressure medium line 26b to the late adjustment chambers 25. At the same time, pressure fluid from the advance chambers 24 reaches the first working port A via the first pressure medium line 26a via the first annular groove 42 with the first volume storage port V ₁ in conjunction. In this case, the pressure medium passes through a fifth control surface 48, which is defined by the overlap of the radial opening 37 of the first working port A with the first annular groove 42. If the volume accumulators 31 are completely filled, pressure medium from the volume accumulators 31 reaches the second volume accumulator connection V ₂ via the fourth pressure medium line 26 v, which is connected to the outlet connection T via the second annular groove 42. In this case, the pressure medium passes through a sixth control surface 49, which is defined by the overlap of the radial opening 37 of the second volume storage port V ₂ with the second annular groove 45. In the illustrated embodiment, the sixth control surface 49 is smaller than the fourth control surface 46 and smaller than the fifth control surface 48 executed. Thus, the outflow from the Frühverstellkammern 24 is throttled with respect to the inflow to the retardation 25 and thus realized in this embodiment, a flow control. At the same time, the feed to the volume accumulators 31 is throttled in comparison to the first two embodiments, whereby the pressure medium enters under higher pressure in this.
The operation of the third embodiment is analogous to the first two embodiments.

The presented devices 11 are characterized by significantly increased Phasenverstellgeschwindigkeiten. In addition, occur due to the realized flow control with small displacements of the control piston 38, no high changes in the pressure medium inflow to the pressure chambers to be filled 24, 25, whereby the control of the phase position is greatly facilitated. A further advantage is that the positions of the control piston 38 to be adjusted relative to the valve housing 36 is independent of whether the volume flow delivered by the pressure medium pump 27 covers or does not cover the pressure medium requirement of the pressure chambers 24, 25 to be filled. Thus, only one control strategy is needed, which can be applied to both operating states of the internal combustion engine 1, whereby the control of the device 11 is further simplified.

reference numeral

1

Internal combustion engine

2

crankshaft

3

piston

4

cylinder

5

traction drive

6

intake camshaft

7

exhaust

8th

cam

9

Inlet gas exchange valve

10

Auslassgaswechselventil

11

contraption

12

Phase adjustment device

13

control valve

14

Sprocket

15

driving element

16

output element

17

side cover

18

hub element

19

wing

20

peripheral wall

21

head Start

22

Pressure fluid chamber

23

boundary wall

23a

early stop

23b

late stop

24

advance chamber

25

retard chamber

26a

first pressure medium line

26b

second pressure medium line

26p

third pressure medium line

26v

fourth pressure medium line

26t

fifth pressure medium line

27

Hydraulic pump

28

Pressure medium reservoir

29

direction of rotation

30

valve spring

31

volume storage

32a

first pressure medium channel

32b

second pressure medium channel

33

first check valve

34

second check valve

35

-

36

valve housing

37

radial opening

38

spool

39

feather

40

first piston opening

41

first control surface

42

first ring groove

43

second control surface

44

third control surface

45

second annular groove

46

fourth control surface

47

second piston opening

48

fifth control surface

49

sixth control surface

50

third check valve

A

first work connection

B

second work connection

P

inflow connection

V ₁ , V ₂

Volume accumulator port

T

drain connection

S1

first control position

S2

second control position

S3

third control position

Claims (10)

1. Device (11) for variably adjusting the timing of gas exchange valves (9, 10) of an internal combustion engine (1) having

   - a hydraulic phase adjustment unit (12) and at least one volume accumulator (31),

   - wherein the phase adjustment unit (12) can be brought into drive connection with a crankshaft (2) and a camshaft (6, 7) and has at least one advance chamber (24) and at least one retardation chamber (25), which can be supplied with pressure medium or from which pressure medium can be discharged via pressure medium lines (26a, b, p, v),

   - wherein a phase position of the camshaft (6, 7) relative to the crankshaft (2) can be adjusted in the direction of early timing by supplying pressure medium to the advance chamber (24) while simultaneously allowing pressure medium to flow out of the retardation chamber (25),

   - wherein a phase position of the camshaft (6, 7) relative to the crankshaft (2) can be adjusted in the direction of late timing by supplying pressure medium to the retardation chamber (25) while simultaneously allowing pressure medium to flow out of the advance chamber (24),

   - wherein pressure medium can be supplied to the volume accumulator or accumulators (31) during the operation of the internal combustion engine (1),

   - characterized in that at least two pressure medium channels (32a, b) are provided in addition, wherein the first pressure medium channel (32a) opens into one of the volume accumulators (31), on the one hand, and communicates with the advance chamber (24), on the other hand, wherein the second pressure medium channel (32b) opens into one of the volume accumulators (31), on the one hand, and communicates with the retardation chamber (25), on the other hand, and wherein each of the pressure medium channels (32a, b) is assigned a check valve (33), which prevents a pressure medium flow from the respective pressure chamber (24, 25) to the volume accumulator (31) and can permit a pressure medium flow in the opposite direction.
2. Device (11) according to Claim 1, characterized in that the volume accumulator (31) is arranged within the phase adjustment unit (12).
3. Device (11) according to Claim 1, characterized in that the volume accumulator (31) communicates or can be connected to a pressure medium reservoir (28) of the internal combustion engine (1) via one or more pressure medium lines (26v, t).
4. Device (11) according to Claim 2, characterized in that the volume accumulator (31) can be connected to a pressure medium reservoir (28) via one or more pressure medium lines (26v, t), wherein the outlet area of the pressure medium channels (32a, b) into the volume accumulator (31) is arranged at a greater distance from the axis of rotation of the phase adjustment unit (12) than the outlet area of the pressure medium lines (26v, t) into the volume accumulator (31).
5. Device (11) according to either of Claims 3 or 4, characterized in that the pressure medium line or lines (26v, t) which connect the volume accumulator (31) to the pressure medium reservoir is/are assigned a check valve (50), which prevents a pressure medium flow from the pressure medium reservoir (28) to the volume accumulator (31) and can permit a pressure medium flow in the opposite direction.
6. Device (11) according to Claim 1, characterized in that the volume accumulator (31) is fed with pressure medium from the pressure chambers (24, 25).
7. Device (11) according to Claim 1, characterized in that the volume accumulator (31) is fed with pressure medium directly from the pressure medium pump (27).
8. Device (11) according to Claim 1, characterized in that the device (11) has a control valve (13), by means of which the pressure medium supply from a pressure medium pump (27) to the pressure chambers (24, 25) and the pressure medium discharge from the pressure chambers (24, 25) can be controlled.
9. Device (11) according to Claim 8, characterized in that the control valve has an inlet port (P), a first and a second working port (A, B) and at least one first volume accumulator port (V₁),

   - wherein a first pressure medium line (26a) is provided, which communicates with the first working port (A), on the one hand, and opens into the advance chamber (24), on the other hand,

   - wherein a second pressure medium line (26b) is provided, which communicates with the second working port (B), on the one hand, and opens into the retardation chamber (25), on the other hand,

   - wherein a third pressure medium line (26p) is provided, which communicates with the inlet port (P), on the one hand, and communicates with a pressure medium pump (27), on the other hand,

   - wherein at least one fourth pressure medium line (26v) is provided, which communicates with the volume accumulator port (V₁), on the one hand, and opens into the volume accumulator (31), on the other hand, and

   - wherein a connection between the inlet port (P) and the first or second working port (A, B) and a connection between the volume accumulator port (V₁) and the other working port (A, B) can be established by means of the control valve (13).
10. Device (11) according to Claim 8, characterized in that

    - the control valve has an inlet port (P), a first and a second working port (A, B), two volume accumulator ports (V₁, V₂) and a drain port (T),

    - wherein a first pressure medium line (26a) is provided, which communicates with the first working port (A), on the one hand, and opens into the advance chamber (24), on the other hand,

    - wherein a second pressure medium line (26b) is provided, which communicates with the second working port (B), on the one hand, and opens into the retardation chamber (25), on the other hand,

    - wherein a third pressure medium line (26p) is provided, which communicates with the inlet port (P), on the one hand, and with a pressure medium pump (27), on the other hand,

    - wherein two fourth pressure medium lines (26v) are provided, which open into the volume accumulator (31), on the one hand, and each communicate with one of the volume accumulator ports (V₁, V₂), on the other hand,

    - wherein a fifth pressure medium line (26t) is provided, which communicates with the drain port (T), on the one hand, and with a pressure medium reservoir (28), on the other hand,

    - wherein a connection between the inlet port (P) and the first or second working port (A, B), a connection between one of the volume accumulator ports (V₁, V₂) and the other working port (A, B) and a connection between the other volume accumulator port (V₁, V₂) and the drain port (T) can be established by means of the control valve (13).

Images