WO2007125050A2

WO2007125050A2 - Valve for a camshaft adjuster

Info

Publication number: WO2007125050A2
Application number: PCT/EP2007/053922
Authority: WO
Inventors: Michael Busse; Andreas Röhr; Sebastian Schubert; Michael Hauser
Original assignee: Schaeffler Kg
Priority date: 2006-05-03
Filing date: 2007-04-23
Publication date: 2007-11-08
Also published as: DE102006020320A1; WO2007125050A3

Abstract

Created is a valve for a camshaft adjuster, having a valve housing (100) with a first fluid port (P) and with at least one second fluid port (B). The valve additionally has a control piston (101). The control piston has an axially closed hollow body, a control edge (118), a first annular groove (110) and a second annular groove (112), wherein in a first operating state which corresponds to a rest state, the first fluid port is sealed off by means of the control edge. An undesired unlocking of a locking bolt can thereby be prevented. In a second operating state, the first fluid port and the second fluid port are coupled by means of the first annular groove and by means of the second annular groove via an operative connection.

Description

Name of the invention

Valve for a camshaft adjuster

description

Field of the invention

The present invention relates to the field of camshaft adjusters. In particular, the present invention relates to a valve for a camshaft adjuster and a method for pressurizing a camshaft adjuster plate by means of a valve.

To control a gas change in a four-stroke internal combustion engine, a camshaft or control shaft is driven at half the engine speed of the crankshaft. With its cams, the camshaft opens the gas exchange valves designed separately for pushing out the exhausted gases and sucking in the fresh gases against the pressure in the cylinder and against the forces of the valve springs. The valves are actuated by the cams mechanically actuating the valves. For this purpose, the camshaft is mounted in the internal combustion engine such that the cams mounted on it rest on cam followers, for example cup tappets, drag levers or rocking levers, which in turn are in operative connection with the valves.

The coupling of a camshaft with the crankshaft is made via a timing chain or a timing belt. By this substantially rigid coupling, there is a fixed phase relationship between the rotation of the camshaft and the rotation of the crankshaft.

However, it has been found that it can be advantageous for the operation of an internal combustion engine, in particular with regard to the fuel consumption and the increase of the power, to use this fixed phase relationship between adjust the camshaft and crankshaft during engine operation. By means of hydraulic or electric camshaft adjustment systems, it is possible to adjust the phase relationship between the camshaft and the crankshaft as required. A hydraulic camshaft adjusting system has a camshaft adjuster and a valve. The camshaft adjuster operates on the vane principle and is placed between the timing gear and the camshaft to be adjusted. In the event that no oil pressure in the internal combustion engine is present, for example when starting the engine, the camshaft adjuster still has a mechanical lock. The locking position is in an angular position within the adjustment range of the camshaft adjuster. The valve in the form of a central valve controls the replacement of the oil between the camshaft phaser and the engine oil circuit. It is located in the center of the rotor.

As soon as oil flows around the central valve, a lock connecting a stator and a rotor of the camshaft adjusting system is unintentionally released, whereby the rotor, which is connected to the crankshaft, opposite the stator, which is connected to the crankshaft via the control drive , can twist. An uncontrolled opening of the lock, the so-called center lock, also leads to undesirable noises in the camshaft adjusting system, which adversely affect the driving comfort of the vehicle.

A valve for a device for changing the control time of an internal combustion engine is known from the publication DE 10 2004 038 252 A1. Variable valve timing control devices are also known from the documents US 2002/0124821 A1 and US 2003/0010303 A1.

It is an object of the present invention to provide an efficiently operable valve. Accordingly, a valve for a phaser and a method for pressurizing a camshaft adjuster is provided by means of a valve.

According to an exemplary embodiment of the present invention, a valve for a phaser is provided which includes a valve housing and a control piston. The valve housing has a first fluid port and at least one further fluid port. The control piston has at least one control edge. Furthermore, the control piston has a first annular groove and a second annular groove, wherein the control piston is axially closed. In a first operating state, a rest state, the first fluid port of the valve housing is sealed by means of the first control edge.

In a second operating state, for example during normal operation of an engine at a normal operating speed, the first fluid port and the second fluid port are by means of the first annular groove and the second annular groove of the

Control piston coupled via an operative connection. The coupling of the ports can be effected by means of a fluid which is supplied with a pressure at the first fluid port and which is pressurized at the second fluid port.

It should mean axially closed, that the control piston has an axis of symmetry, which defines an axial direction. The control piston may be designed to be rotatable about the axis of symmetry. The control piston may be displaceable in the axial direction, but may have a closure in the axial direction. The closure can prevent a fluid from penetrating into the control piston in the axial direction and can prevent the fluid from escaping from the control piston in the axial direction.

The idle state should describe an energy-free state of the camshaft adjuster. The camshaft adjuster no energy or power is supplied from the outside. An energy input could be in the form of an electrical current or a mechanical force. Internally, the system can however, have stored an energy. Thus, energy can be stored in the compression or expansion of a spring. However, the first operating state may be a stable state that can be maintained without the supply of external power or power. The idle state may also refer to a portion of an engine starting process.

According to another embodiment of the present invention, a method for pressurizing a camshaft adjuster, in particular the hydraulic chambers of a camshaft adjuster, is indicated by means of a valve. For this purpose, an operating state is initially set or an operating state is detected and, depending on the operating state, the flow of a fluid is influenced by the camshaft adjuster. The fluid is provided at the first fluid port pressurized. In a first operating state, a sealing of the first fluid port takes place by means of the control edge of the control piston. Consequently, the flow of the fluid through the first fluid port is prevented.

In the first operating state, the camshaft adjuster, in particular the valve is in an idle state or an engine start phase. An axial flow of the fluid into the control piston and out of the control piston is prevented by end-mounted axial closures on the hollow body of the control piston.

In a second operating state, the first fluid port is connected to the second fluid port via the first annular groove and the second annular groove via an operative connection. The active compound may be, for example, a pressurized fluid. The operative connection can, for example, run in the interior of the hollow body of the control piston. It is possible that the operative connection is formed by means of a pressurized fluid or else via a mechanical coupling. Liquids can not be compressed substantially. As a result, they can pass on a pressure which is exerted on them and thereby create an operative connection.

Hydraulic camshaft phasing systems may include a camshaft adjuster with a center lock and a central valve. The camshaft adjuster may have at least one hydraulic chamber, which is divided into two hydraulic sub-chambers. The two hydraulic sub-chambers can be expanded or contracted with appropriate pressurization by means of a fluid or oil. The hydraulic chamber can be divided by means of a separating element into the two sub-chambers, for example the chamber A and the chamber B.

By applying pressure to the chamber A, a force imbalance with respect to the chamber B can be produced. The force imbalance can cause an expansion of the volume in the chamber A. The resulting pressure can be passed by means of a partition between chamber A and chamber B. Since the entire chamber in which the chamber A and the chamber B lie can not be variable in their volume, the increase in the volume of the chamber A can lead to a reduction in the volume of the chamber B. Thereby, a phase angle of a rotor, which is in communication with a corresponding partition wall, relative to the stator, so for example a chamber housing, can be adjusted.

The rotation of the rotor relative to the stator can be prevented by means of a center lock in the camshaft adjusting system. A center lock can be realized by means of two axial locking pistons in the rotor of the camshaft adjuster, wherein the pistons engage or engage in locking recesses of a locking cover and can thus hold the camshaft adjuster in the locking position. The locking piston can be pressed by means of a spring force in the locking latches. To release the locking latches, the locking pistons can be flowed through by an oil, it being possible for the locking pistons to be pushed out or released from the locking latches by means of the prevailing oil pressure. As a result, the camshaft adjuster, in particular the rotor, can be released. Ie. that after the center lock has been released or after the locking piston has been released, a rotation of the camshaft adjuster rotor relative to the camshaft adjuster stator can be made possible. By solving the lock, the camshaft adjuster can be released to make changes in the adjustment angle. With a clamping of the camshaft adjuster by means of the locking bolts, one can speak of a mechanical restraint, while in a control by means of the pressure distribution in the chamber A and the chamber B, one can speak of a hydraulic restraint.

For example, unlocking may be achieved toward a position "late" by oil pressure from chamber B. Unlocking in the "early" direction may be achieved by an oil pressure from chamber A. " The designation or position "late" here means a return of the phase angle, ie a rotation of the rotor such that the cams actuate the valves later than a normal position, whereas the position "early" means an adjustment of a phase angle with respect to a reference phase angle between the rotor and the stator of the camshaft adjuster, and thus also an adjustment of a phase angle between the crankshaft and the camshaft such that the actuation of the valves relative to a normal position can take place earlier.

The triggering of the lock, so the release of the lock, can be done even at a slight oil pressure. In other words, it means that already at an engine starting process, the central valve and in particular the FIu- idkreislauf can be acted upon by the camshaft adjustment system with a low oil pressure. Due to this low oil pressure, the locking bolt already be solved, although the low pressure is not sufficient to adjust a phase angle between the rotor and the stator of the camshaft adjustment.

Due to the low pressure in the chambers and due to the released locking bolt, there may be an uncontrolled movement of the camshaft Verstellerrotors over the camshaft adjuster stator. This uncontrolled and uncontrollable movement can cause noise when starting the engine. By means of the sealing of a port of a central valve, premature oil flow through the fluid circuit of the camshaft adjusting system can be avoided.

A camshaft phaser central valve or valve may be a proportional valve with ports for a pressurized oil, an oil sump, a first port, or a second port. In general, a port can be an opening or a connection, via which a working fluid such as a pressure oil can be supplied to the valve or via which the working fluid can be removed again.

At the pressure oil port, a pressurized fluid can be provided, which can be selectively supplied via the central valve to a first hydraulic chamber A or a second hydraulic chamber B. About this operative connection, a pressure transmission of the pressure oil to the hydraulic chamber A and the hydraulic chamber B take place. By changing the pressures in the chambers A and B, the phase angle of the camshaft relative to the crankshaft can be adjusted. Excess oil can be discharged through the tank ports to an oil pan or tank.

By sealing a fluid port, for example the pressure oil port, it is possible to prevent a pressure being built up in the camshaft adjusting system in a first operating state, that is, for example, an engine start phase or a rest phase. By locking the fluid port in the first operating state can also early release the lock and thus a noise of the engine can be avoided. The first operating state can also be a relaxed, ie energy-free state, which sets in, for example, an emergency running situation.

The pressurization of the two hydraulic chambers A and B can be controlled by the closure of the pressure medium supply port, alternatively, the working port A or the working port B can be closed so that the pressure can not get into one of the pressure chambers and unintentionally the locking means a pin can solve.

In particular, it can be prevented that a volume flow flows from the pressure oil port P to the working port B and thus pressurizes the chamber B. It is thus also the unwanted adjustment in the camshaft lenverstellsystemstellung "late" already be prevented during the engine start phase. A blocked pressure oil port P can thus prevent a flow of air between the P port and the B port, whereby no independent release of the locking piston takes place.

In a second operating state, ie when a desired speed, in particular a working speed, is reached, a fluid flow between the first fluid port and the second fluid port can be achieved by changing the central valve or valve via a first annular groove and a second annular groove respectively. For this purpose, an operative connection between the first and second annular groove is desired. The operative connection can take place, for example, by means of the pressurized fluid, which can be provided at the first annular groove and passed on to the second annular groove.

In accordance with another exemplary embodiment of the present invention, a valve is provided wherein the valve housing further includes a third fluid port and a fourth fluid port. If the valve is in the second operating state, an operative connection between the third fluid port and the fourth fluid port can prevail simultaneously with the operative connection between the first annular groove and the second annular groove. Thereby For example, the third fluid port and the fourth fluid port may be coupled via an operative connection. This active connection can take place for example by means of the passage of the third fluid port and the fourth fluid port of a pressurized oil. For this operative connection, the valve may provide communication between the third and fourth fluid ports.

By the operative connection between the third fluid port and the fourth fluid port, a drain of an oil from one of the hydraulic chambers of the camshaft adjuster can be controlled. For example, the third fluid port may provide access to the hydraulic chamber A, while the fourth fluid port may be connected to an oil pan or tank. Thus, during the second operating state via the pressure oil port P and via the first and second annular groove of the valve, a pressurized oil can enter the chamber B. Thus, the volume of the chamber B can increase by the existing in the chamber A oil is compressed so that the oil on the working port A, in particular via the third fluid port, and the tank port, in particular via the fourth fluid port , is discharged.

According to yet another exemplary embodiment of the present invention, the fourth fluid port is disposed on an end face of the valve housing. Due to the frontal position of the fourth fluid port, a short connection path between the third fluid port and the fourth fluid port can be provided, since a direct route for the procedure can be selected.

According to yet another exemplary embodiment of the present invention, there is provided a valve in which, in a third mode of operation, the first fluid port is coupled to the third fluid port via the first annular groove and via the second annular groove via an operative connection. In addition, in the third operating state, the second fluid port is coupled to a fifth fluid port via an operative connection. The third operating state may correspond to a position of the control piston in a valve housing. The first fluid port may in turn be a pressurized oil port to which a pressurized fluid or oil is provided. This oil can reach the second annular groove, since the first annular groove and the second annular groove are coupled via an operative connection in the hollow body of the control piston. At the second annular groove, the fluid can escape from the control piston, for example, through an opening and reach the third fluid port. While in the second operating state, an outflow via the third fluid port, such as the working port A can take place, in the third operating state, a pressure, in particular a pressurized oil, via the second annular groove and the third fluid port into the chamber A reach. As a result, the pressure of the oil in the chamber A may increase, whereby the volume of the chamber A can increase and displace the oil present in the chamber B.

The displacement of the oil in chamber B can be made possible because in the third operating state, the oil can be discharged into the tank by means of an operative connection of the second fluid port and the fifth fluid port. The second fluid port may be in the third operating state with the chamber B verbundern, while the second fluid port may be connected to the tank.

Consequently, the flow direction of a fluid or oil can be controlled by the camshaft adjusting system by adjusting the operating state. The Bethebszustände may refer to positions of the control piston within the valve housing. By targeted approach of these layers, consequently, an adjustment of the phase angle of the camshaft adjuster can be controlled.

In yet another exemplary embodiment of the present invention, a valve is provided wherein the operative connection between the second fluid port and the fifth fluid port is a third annular groove. By providing the operative connection on a control piston outside, a connection of the second fluid port and the fifth fluid port can be established by the adjustment of the control piston.

According to yet another exemplary embodiment of the present invention, the control edge of the control piston has an extent that is greater than the opening area of one of the fluid ports.

For example, the control edge may have an extension that is greater than the opening area of the first fluid port. In this case, the opening area may be composed of a plurality of small openings, in particular opening areas, which form the first fluid port. As a result, a sealing of the first fluid port can take place, so that a fluid or oil supply of the camshaft adjuster can be prevented by the fluid port.

According to a further exemplary embodiment of the present invention, the control piston is arranged to slide axially in the valve housing. The adjustment between the first, second or third operating state can be effected by a linear movement, because the control piston is arranged to slide linearly in the valve housing. The valve housing may be formed as a cylinder in which the control piston can move. The inner wall of the cylinder can be connected to a lateral surface which can also be interrupted by the annular groove. This connection can provide a guide for the control piston. In a positive fit of the control piston in the valve housing, a seal can be made, whereby the annular grooves can be separated from each other by the control edge or by other annular flanges.

In yet another exemplary embodiment of the present invention, the control piston may be coupled to or coupled to an electromagnet. In this case, the electromagnet is set up to move the control piston axially in the valve housing. The electromagnet can a Pin, wherein the pin can be coupled to the control piston. The pin may have a spherical end.

By setting a duty cycle, a swing of a pin of an electromagnet can be adjusted. A duty cycle may be by means of switching on and off a voltage for a certain duration during a time interval. By the percentage distribution of the on versus the off duration can be controlled in particular a supplied power or power to the electromagnet. An electromagnet, which is coupled to a control piston, can adjust the immersion depth of the piston in the cylinder. For example, three valve positions can be distinguished by means of three operating states. The immersion depth can be determined for example by the distance of an end face of the control piston from the end face of the valve housing.

According to yet another embodiment of the present invention, a duty ratio of the solenoid is assignable to an operating state of the valve. This assignment makes it possible to set the immersion depths of the piston into the cylinder in a targeted manner during the different operating states.

According to yet another exemplary embodiment of the present invention, the valve has a restoring element, wherein the restoring element is designed to restore the first operating state in the event of a deviation from the first operating state. The first operating state may, for example, prevail during an engine start phase or run-flat phase of the engine, wherein during the engine start phase possibly no energy is available for the operation of the electromagnet. Consequently, the first operating state can also be taken during a start phase, during which a sealing of the first fluid port is to take place. The return element may for example be a spring which is arranged between an end face of the valve housing and the end face of the control piston. This allows an immersion depth of a control piston in a Blind hole or valve housing or the valve cylinder done. The control piston may have a cup-shaped cavity, which may be closed with a lid. Thereby, an axial flow of the fluid into the control piston and out of the control piston can be prevented.

Illustratively, this means that the valve or central valve has a thread externally on the valve housing and is screwed axially into a camshaft until the collar rests against the valve housing of the central valve on the inside of the end face of the camshaft. The thread can be formed as a left-hand thread or as a right-hand thread. In the central valve, a valve piston or control piston may be located, which can be axially displaced against the spring force of a compression spring via a pin of a coaxially arranged magnet via the pressure piece pressed into the piston, which is coupled to the electromagnet. Thus, the valve piston does not fall out of the valve housing during assembly, this can be axially secured by a locking ring. On the other side of the valve piston, a spring retaining ring may be located on which the compression spring is supported.

When the engine is started, when the central valve and in particular the solenoid is de-energized, the P port can be closed by means of the control edge and the A port can be connected to the T port. Here, in the B-

Port no volume flow to flow. When the engine is started there is no connection between the P-port and the B-port and thus a connection to the B-port

No oil pressure build up at the port connected to the B-chamber, which leads to the automatic release of the locking piston in the "late" direction.

After starting the engine, the central valve can be energized and the local position of the control piston can be changed with respect to the de-energized case. Thus, the P port and the B port can be connected and at the same time the A port can be connected to the T port. If a duty cycle of the electromagnet is greater than the Mittentastverhältnis, then in the energized case, the P-port and the A-port can be connected and at the same time the B-port with the T-port. By means of the Valve can be created a cost-effective solution for the sealing of the T-port.

Many developments of the invention have been described with reference to the valve. These embodiments also apply to the method for pressurizing a camshaft adjuster by means of a valve.

In the following, advantageous embodiments of the following invention will be described with reference to the figures.

Fig. 1 shows a valve in a de-energized state according to an exemplary embodiment of the present invention.

2 shows a valve in an energized state according to an exemplary embodiment of the present invention.

The illustrations in the figures are schematic and not to scale. In the following description of Figs. 1 and 2, the same reference numerals are used for the same or corresponding elements.

Fig. 1 shows the valve housing 100 in which the control piston or valve piston 101 is arranged. Both the valve housing 100 and the valve piston 101 are configured as a round rotating part. The design as a round cylindrical rotary member makes it easier to accommodate the valve 102 axially in a camshaft, which is not shown in Fig. 1, accommodate. For accommodation in a camshaft, the valve 102, which comprises the valve housing 100 and the valve piston 101, are axially inserted and screwed with the thread 103 on the shell side of the valve housing in an internal thread of the camshaft until the collar 104 of the valve housing 100 at the Front side of the camshaft rests.

The valve housing 100 has a first port, the pressure oil port P, which, with a not shown in Fig. 1 oil pressure line to provide a Pressure-applied fluid is connected. Furthermore, the valve housing 100 has a second fluid port, the working port B, which is connected to a likewise not shown in Fig. 1 hydraulic chamber B of a camshaft adjuster. In addition, the housing 100 has the third fluid port A connected to the pressure chamber A of the camshaft adjuster, which is arranged directly next to the fluid port B.

The collar 104 opposite end face of the valve housing cylinder 100 is at least partially closed by the spring retaining ring 105. The spring retaining ring 105 is a molded part which is pressed against the inner wall of the housing 100. The spring retaining ring 105 has an axial or axially disposed fourth fluid port T ₃ , which is connected to a tank or an oil pan. Between the pressure oil port P and the working port B, the fifth fluid port T _{b is} radially arranged, which is also connected to the tank or the oil pan.

The fluid ports P, T _b , B, A are formed as annular grooves in the cylindrical valve housing 100. The annular grooves P, T _b , B, A have the openings 106, 107, 108 and 109, which allow a connection between the outside of the housing hollow cylinder 100 and the inside of the housing 100. Along the circumference of the annular grooves P, T _b , B, A, a plurality of openings 106, 107, 108 and 109 may be located. The openings 106, 107, 108, 109 have a rectangular shape with rounded edges.

About the apertures 106, 107, 108 and 109 can enter the cylinder interior pressure oil. The cylinder interior is partially filled by a piston 101. The control piston 101 is cylindrical and has a cup-shaped cavity in its interior. The lateral surface and in particular the lateral surface of the annular flanges 118, 1 19, 120 of the control piston 101, is located on the inner wall of the valve housing 100 close to. Only the annular groove 1 10, 1 11 and 1 12 divide the inner volume of the valve housing 100 in the chambers 1 10, 1 11 and 1 12. Since the length of the piston 101 is shorter than the length of the valve housing 100, at the end face of the valve housing ses 101 an additional chamber 1 13, which is accessible via the tank port T _a formed.

The piston 101 has a cavity 14 which extends from the left end side of the control piston to the right control edge 120 of the second annular groove 112. This cavity is closed with the arranged on the left side shown in Fig. 1 pressed-pressure piece 1 15. The pressure piece 1 15 is pressed into the piston. In the first annular groove 110 a plurality of window-shaped passages 1 16 are arranged, which allow a connection of the ring nutkammer 1 10 in the piston interior 1 14. Likewise, the window 1 17 allows a connection between the cavity 114 and the second annular groove 1 12. Consequently, the annular groove chambers 1 10 and 1 12 communicating with each other.

The control edge 118 is designed such that it seals the P-port in the de-energized operating state or idle state illustrated in FIG. The B-control edge 1 19 partially seals the B-port, so that in the de-energized state, a connection from the B-port B into the piston interior 114 can be created. The A control edge 120 only partially covers the A port 109 in the de-energized state shown in FIG. 1, so that a connection of the A port to the chamber 1 13 and the tank port T _a can be established.

The return element or the return spring 121 presses the valve piston 101 against the retaining ring 122, which secures the valve piston against falling out. For force application, the spring 121 is disposed between the spring retaining ring 105 and the piston wall 123. With the pin 124 of the solenoid 125 is coaxial with the valve piston with the pressure piece 1 15 coupled. By means of the pin 124, the electromagnet 125 can exert a force against the return spring 121 on the valve piston 101, so that the valve piston 101 slides axially in the cylinder 100 in the direction of the securing ring 105. Fig. 1 shows the de-energized state, which is established after switching off a supply voltage for the electromagnet 125. Since the voltage is switched off, no energy is supplied from the outside. Energy is stored only in the partially tensioned spring 121. The system is thus in a stable state.

By means of the electromagnet 125, different Bethebszustände the valve can be adjusted. For driving in and out of the pin, a current is applied to the electromagnet 125 by supplying the magnet 125 with a voltage, and due to an adjustable pulse duty factor of the magnet, the operating state is determined.

FIG. 2 shows an energized operating state of the valve according to an exemplary embodiment of the present invention. In Fig. 2, the solenoid 125 is energized, as is the case for example in an operating state after the engine start. In comparison to FIG. 1, the distance between the housing wall 123 and the securing ring 105 is smaller. Consequently, the pin 124 is extended further than in Fig. 1, whereby the return element 121 is further compressed. By the compression of the spring 121, a restoring force by the spring 121, the valve piston is displaced so that the left edge of the control edge 1 18 18 a connection between the opening 106 and the window 1 16 allows. This connection takes place via the annular groove chamber 10.

Consequently, a fluid supplied to the port P with pressure can reach the interior of the piston 114 along the arrow 200. Since the interior of the front side is limited by the piston wall 123 and the pressure piece 1 15 and also radially through the wall of the piston 101, the fluid propagates in the direction of the opening 1 17. About the opening 117, the fluid enters the annular groove 1 12 and since by means of control edge 19 1 Port B is partially sealed, the fluid passes along the arrow 201 in the port B connected to the hydraulic chamber B. The penetrating into the hydraulic chamber B oil displaces Oil from the hydraulic chamber A, wherein the displaced oil along the Arrow 202 in the only partially closed by the control edge 120 chamber 113 passes. The displaced from chamber A oil is finally forwarded via the output port T _a to the oil pan.

The case shown in Fig. 2 shows an energization of the electromagnet 125 with a duty cycle between 5% and the Mittentastverhältnis of about 50%. The engine control unit calculates the target angle from an existing engine speed and an existing load condition. If the actual angle deviates from the setpoint angle, a controller in the motor controller changes the duty cycle so that the difference between the desired and actual angles becomes smaller until a match is found. The duty cycle is influenced by the temperature in the electromagnet. The higher the temperature, the greater the internal resistance and the greater the actual duty cycle for a particular valve piston position. With an increase in the duty cycle over the Mittastastverhältnis, ie in a range of the duty cycle of the electromagnet of 50% to 100%, the piston is pressed into the cylinder against the return spring 121 such that the control edge 1 19 the exit of the oil from the Piston interior 114 instead of port B to the port A. Thus, pressure is applied to the chamber A, whereby oil from the hydraulic chamber B via the port B and the opening 108 to the annular groove chamber 1 1 1 delivers. The oil spreads in the annular groove chamber 1 1 1 and passes through the opening 107 to the tank port T _b . This allows drainage of the oil to the oil pan.

Consequently, by adjusting the duty ratio of the solenoid 125, the local position of the valve piston 101 in the cylinder 100 can be adjusted. The setting sets an operating state. In the first operating state of the access port P is closed, whereby neither pressure to the chamber B nor to the chamber A is passed. Accordingly, it is also possible to close Port A or Port B.

If the second operating state is set and a liquid with a corresponding pressure is supplied to the port P, in the second Driven state of the chamber B, the pressure supplied. Finally, by setting the third operating state, the pressure of chamber B can be subtracted and directed in the direction of chamber A, and thus the phase position of the camshaft adjuster can be controlled.

In addition, it should be understood that "comprising" does not exclude other elements or steps and "a" or "an" does not exclude a plurality. "Further, it should be noted that features or steps described with reference to one of the above embodiments also may be used in combination with other features or steps of other embodiments described above.

Claims

claims

A valve, for a phaser, comprising: a valve housing (100) having a first fluid port (P) and at least one second fluid port (B); and a control piston (101); wherein the control piston (101) has a control edge (1 18); wherein the control piston (101) has a first annular groove (1 10); wherein the control piston (101) has a second annular groove (1 12); wherein the control piston (101) is formed as an axially closed hollow body; wherein in a first operating state, the first fluid port (P) by means of the control edge (1 18) is sealed; wherein the first operating state is a rest state; wherein in a second operating state, the first fluid port (P) and the second fluid port (B) by means of the first annular groove (1 10) and by means of the second annular groove (1 12) are coupled via an operative connection.

The valve of claim 1, wherein the valve housing (100) further comprises: a third fluid port (A); a fourth fluid port (T ₃ ); and wherein in the second operating state the third fluid port (A) is coupled to the fourth fluid port (T ₃ ) by means of an operative connection.

3. Valve according to claim 2, wherein the fourth fluid port (T ₃ ) on an end face of the valve housing (100) is arranged.

4. Valve according to claim 2 or 3, wherein in a third operating state of the first fluid port (P) and the third fluid port (A) by means of the first annular groove (1 10) and the second annular groove (1 12) via an operative connection coupled; and wherein in the third operating state, the second fluid port (B) is coupled to a fifth fluid port (T _b ) via an operative connection.

5. Valve according to claim 4, wherein the operative connection is a third annular groove (1 1 1).

6. Valve according to one of claims 1 to 5, wherein the control edge (1 18) has an extension which is greater than the opening area of the fluid ports (P, B, A, T _b ).

7. Valve according to one of claims 1 to 6, wherein the control piston (101) in the valve housing (100) is arranged axially slidably.

8. A valve according to claim 7, wherein the control piston (101) is coupled to an electromagnet (125); wherein the solenoid (125) is arranged to move the control piston (101) axially in the valve housing (100).

9. Valve according to claim 8, wherein an operating state, a duty cycle of the electromagnet (125) can be assigned.

10. The valve of claim 1, further comprising: a return member; wherein the return element (121) is designed to produce the first operating state in the event of a deviation from the first operating state.

11. A method for pressurizing a camshaft adjuster by means of a valve according to one of claims 1 to 10, the method comprising:

Setting an operating condition; Sealing the first fluid port (P) with the control edge (1 18) of the control piston (101) in a first operating state; wherein the first operating state is a rest state; and wherein the control piston (101) is formed as an axially closed hollow body;

Coupling the first fluid port (P) and the second fluid port (B) by means of the first annular groove (1 10) and the second annular groove (1 12) via an operative connection in a second operating state;

Providing a pressurized fluid to the first fluid port (P).

12. The method of claim 1 1, further comprising:

Coupling the third fluid port (A) to the fourth fluid port (T ₃ ) by means of an operative connection in the second operating state.

13. The method of claim 1 1, further comprising:

Coupling the third fluid port (A) to the fourth fluid port (T ₃ ) by means of the third annular groove in the second operating state.

14. The method of claim 1, further comprising:

Coupling the first fluid port (P) to the third fluid port (A) in a third remedial condition; and

Coupling the second fluid port (B) to the fifth fluid port (T _b ) via an operative connection; Providing a pressurized fluid to the first one

Fluid port (P).

15. The method of claim 1, further comprising: axially moving the control piston in the valve housing.

16. The method of claim 13, further comprising: axially moving the control piston (101) by means of an electromagnet (125).