Cam torque-actuated variable camshaft timing device with a bidirectional oil pressure preload circuit

Abstract

Variable camshaft adjuster for an internal combustion engine, including: a housing arrangement (100) with an outer circumference (101) for receiving a driving force; a rotor arrangement (105) which is arranged coaxially in the housing arrangement (100) for connection with a camshaft, wherein the rotor arrangement (105) defines at least one first vane (104a) which separates a first chamber (117a) in the housing arrangement (100) into a feed chamber (102) and a retardation chamber (103), and at least one second vane (104b) which separates a second chamber (117b) in the housing arrangement (100) into another feed chamber (125) and another retardation chamber (127), wherein at least one of the first (104a) or the second vane (104b) is cam torque actuated and defines a cam torque actuated feed chamber (102) and a cam torque actuated retardation chamber (103), and at least one other of the first (104a) or the second vane (104b) is oil pressure actuated and defines a defined an oil pressure-operated delay chamber (127) and an oil pressure-operated feed chamber (125); a supply line (119) coupled to a fluid inlet; at least one outlet line (121, 122); a control valve (109) that is movable between a feed mode, a deceleration mode and a holding position to direct fluid between the cam torque actuated deceleration chamber (103) and the cam torque actuated feed chamber (102) through a feed line (112), a common line (114) with a deceleration check valve (110) and a feed check valve (108) and a deceleration line (113); wherein, when the control valve (109) is in feed mode, the fluid is directed through the feed check valve (108) from the cam torque-actuated delay chamber (103) to the cam torque-actuated feed chamber (102) and fluid is directed from the cam torque-actuated delay chamber (103) to the cam torque-actuated feed chamber (102) and also through the control valve (109) to the oil pressure-actuated feed chamber (125) and fluid is directed from the oil pressure-actuated delay chamber (127) to the at least one outlet line (122, 121); wherein, when the control valve (109) is in delay mode, the fluid is directed through the delay check valve (110) from the cam torque-actuated feed chamber (102) to the cam torque-actuated delay chamber (103), and fluid is also directed through the control valve (109) to the hydraulically actuated delay chamber (127), and fluid is directed from the hydraulically actuated feed chamber (125) to the at least one outlet line (121, 122); and wherein, when the control valve (109) is in the holding position, fluid is prevented from moving between the cam torque-actuated feed chamber (102) and the cam torque-actuated retardation chamber (103), so that the oil pressure-actuated vane (104b) and the cam torque-actuated vane (104a) are held in position by oil pressure.

Description

GENERAL STATE OF THE TECHNOLOGY - AREA OF INVENTION

[0001] The invention relates to the field of variable camshaft adjusters. More precisely, the invention relates to cam torque-actuated variable camshaft timing devices with a bidirectional oil pressure preload circuit. DESCRIPTION OF RELATED TECHNOLOGY

[0002] It has been shown that operating a variable camshaft timing device adjuster, which uses camshaft torque energy to adjust valve timing, is desirable due to the small amount of oil required by a camshaft torque-actuated variable camshaft timing device. However, not all engines provide sufficient camshaft torque energy across the entire engine operating range to effectively adjust the variable camshaft timing device.

[0003] From US Patent 2007 / 0101962A1, a valve control device adapted to the exhaust valve side of an internal combustion engine is known. A vane element is arranged to rotate with a camshaft relative to a timing sprocket element. At low engine speeds, the vane element is primarily rotated by a camshaft torque actuation mechanism, and at high engine speeds, it is primarily rotated by a hydraulic actuation mechanism. The camshaft torque actuation mechanism is actuated by a changing torque from the camshaft, while the hydraulic actuation mechanism is actuated by a fluid pump. The vane element comprises a first vane, which is arranged for operation in the camshaft torque actuation mechanism, and a second vane, which is arranged for operation in the hydraulic actuation mechanism.The first wing has a shorter radial length and a smaller pressure-bearing area than the second wing.

[0004] A variable camshaft adjuster comprising a housing, a rotor arranged coaxially within the housing, a phase control valve, a switching valve, and a channel connecting the first feed and retardation chamber is described in US 2007 / 0215084A1. The housing and rotor define at least two chambers: a first chamber separated into the first feed and retardation chamber by a first vane, and a second chamber separated into the second feed and retardation chamber by a second vane. The switching valve has a first position in which fluid can flow freely through the channel connecting the first feed and retardation chamber, and in which fluid flow from the phase control valve to the first feed and retardation chamber is blocked.In the second position, the channel connecting the first feed and retardation chamber is blocked, and the fluid can flow freely between the phase control valve and the first feed and retardation chamber. BRIEF SUMMARY OF THE INVENTION

[0005] The present invention supplements the camshaft torque energy with engine oil pressure so that the variable camshaft timing control device can make an adjustment when the camshaft torque is low.

[0006] The present invention therefore discloses a variable camshaft adjuster for an internal combustion engine according to independent claim 1 or according to independent claim 7. BRIEF DESCRIPTION OF THE DRAWING Fig. Figure 1 shows a schematic representation of an adjuster of a first embodiment, which is moved into the feed position. Fig. Figure 2 shows a schematic representation of an adjuster of a first embodiment, which is moved into the delay position. Fig. Figure 3 shows a schematic representation of an adjuster of a first embodiment in the zero or holding position. Fig. Figure 4 shows a schematic representation of an adjuster of a second embodiment, which is moved into the feed position. Fig. Figure 5 shows a schematic representation of an adjuster of a second embodiment, which is moved into the delay position. Fig. Figure 6 shows a schematic representation of an adjuster of a second embodiment in the zero or holding position. DETAILED DESCRIPTION OF THE INVENTION

[0007] Internal combustion engines have employed various mechanisms to vary the relative timing between the camshaft and the crankshaft for improved engine performance or reduced emissions. Most of these variable camshaft timing (VCT) mechanisms use one or more vane adjusters on the engine camshaft (or camshafts in a multi-camshaft engine). As shown in the figures, vane adjusters have a rotor assembly 105 with one or more vanes 104a, 104b attached to the end of the camshaft, which is surrounded by a housing assembly 100 with vane chambers into which the vanes fit. The vanes 104a, 104b may be attached to the housing assembly 100, and the chambers may also be attached to the rotor assembly 105. The outer circumference 101 of the housing forms the pinion, pulley, or gear that engages with the rotor.which receives a driving force through a chain, belt or gear, usually from the crankshaft or possibly from another camshaft in an engine with multiple cams.

[0008] Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. Figure 6 illustrates the operating modes of the VCT adjuster as a function of the spool valve position. The positions shown in the figures define the direction in which the VCT adjuster moves. It will be understood that the phase control valve has an infinite number of intermediate positions, so the control valve not only controls the direction in which the VCT adjuster moves, but also, depending on the discrete spool position, controls the rate at which the VCT adjuster changes positions. Therefore, it will be understood that the phase control valve can also be actuated in an infinite number of intermediate positions and is not limited to the positions shown in the figures.

[0009] In the first embodiment, the connection openings to the oil-pressure-actuated chambers 125, 127 are axially separated by the control valve 109 along the sleeve 116. With regard to Fig. 1, Fig. 2 to Fig. In the first embodiment, the housing assembly 100 of the adjuster has an outer circumference 101 for receiving a drive force. The rotor assembly 105 is connected to the camshaft and arranged coaxially in the housing assembly 100. The rotor assembly 105 has at least two vanes, namely a cam torque-actuated vane 104a and an oil pressure-actuated vane 104b. The cam torque-actuated (CTA) vane 104a separates the chamber 117a, which is formed between the housing assembly 100 and the rotor assembly 105, into a cam torque-actuated (CTA) feed chamber 102 and a cam torque-actuated (CTA) deceleration chamber 103.

[0010] Torque reversals in the camshaft, caused by the forces of the opening and closing engine valves, move the CTA vane 104a. The CTA feed and retardation chambers 102 and 103 are designed to withstand positive and negative torque impulses in the camshaft and are pressurized alternately by the cam torque. The control valve 109 allows the CTA vane 104a to move within the adjuster by permitting fluid flow from the CTA feed chamber 102 to the CTA retardation chamber 103, or vice versa, depending on the desired direction of movement.

[0011] The oil pressure actuated (OPA) vane 104b separates the chamber 117b, which is formed between the housing assembly 100 and the rotor assembly 105, into an oil pressure actuated (OPA) feed chamber 125 and an oil pressure actuated (OPA) deceleration chamber 127. The OPA vane 104b is assisted by engine oil pressure actuation.

[0012] The vanes 104a, 104b can rotate to shift the relative angular position of the housing assembly 100 and the rotor assembly 105.

[0013] A locking pin 130 is slidably housed in a bore in the rotor assembly 105 and has an end section that is biased by a spring 131 towards a recess 132 in the housing assembly 100 and fits into it. In a locked position, the end section of the locking pin 130 engages in the recess 132 of the housing assembly 100. In an unlocked position, the end section of the locking pin 130 does not engage in the housing assembly 100. Alternatively, the locking pin 130 can be housed in the housing assembly 100 and the spring 131 can be biased towards a recess 132 in the rotor assembly 105.

[0014] In Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. 6. The pressure on the locking pin 130 is controlled by the fluid in the OPA feed chamber 125 via line 128, which is in fluid exchange with the recess 132. With the locking pin 130, which is controlled by fluid in the OPA feed chamber 125, the adjuster can be locked in the delay position by venting the OPA feed chamber 125, such that the locking pin 130 engages a delay stop. Alternatively, the pressure on the locking pin 130 can be controlled by fluid in the OPA delay chamber 127. With the locking pin 130, which is controlled by fluid in the OPA delay chamber 127, the adjuster can be locked in the feed position by venting the OPA delay chamber 127 in such a way that the locking pin 130 is engaged against a feed stop.

[0015] The CTA feed chamber 102 is connected to the CTA retarding chamber 103 via the feed line 112, retarding line 113, common line 114, the feed check valve 108, the retarding check valve 110, and the control valve 109. The OPA feed chamber 125 is connected to the control valve 109 via the feed oil pressure line 123, and the OPA retarding chamber 127 is connected to the control valve 109 via the retarding oil pressure line 124.

[0016] A control valve 109, preferably a slide valve, has a slide 111 with cylindrical projections 111a, 111b, 111c, and 111d, which are slidably mounted in a sleeve 116. The control valve can be located remotely from the adjuster in a bore in the rotor assembly 105, which controls the camshaft, or in a centering pin of the adjuster. One end of the slide 111 contacts the spring 115, and the opposite end of the slide 111 contacts a pulse-width modulated variable force solenoid (VFS) 107. The solenoid 107 can be controlled linearly by varying the current or voltage, or, as required, by other methods. Furthermore, the opposite end of the slide 111 can contact and be influenced by a motor or other actuators.

[0017] The position of the slide 111 is influenced by a spring 115, and the solenoid 107 is controlled by the ECU 106. Further details regarding the control of the adjuster are explained in detail below. The position of the slide 111 controls the movement (e.g., to move to the feed position, the hold position, or the deceleration position) of the adjuster and controls whether the locking pin 130 is in a locked or unlocked position. The control valve 109 has a feed mode, a deceleration mode, and a hold position.

[0018] Fig. Figure 1 represents the adjuster, which moves to the feed position. To move into the feed position, the work cycle is increased to more than 50%, the force of the VFS 107 on the slide 111 is increased, and the slide 111 is moved by the VFS 107 into a feed mode to the right until the force of the spring 115 balances the force of the VFS 107.

[0019] In the illustrated feed mode, the slide lift 111a blocks the exit of fluid through the outlet line 121 from the CTA feed chamber 102. Lines 113 and 114 are open to the CTA feed chamber 102 and the CTA retardation chamber 103, respectively. A camshaft torque pressurizes the CTA retardation chamber 103, causing fluid to move from the CTA retardation chamber 103 into the CTA feed chamber 102 and for the CTA vane 104a to move towards the retardation wall 103a. Fluid exits the CTA delay chamber 103 through line 113 to the control valve 109 between slide risers 111a and 111b and is returned to the common line 114 and line 112, which leads to the CTA feed chamber 102.

[0020] Fluid flowing to the CTA feed chamber 102 also flows through the feed line 112 and between the slide risers 111a and 111b to the OPA feed chamber 125 via the line 123, causing the OPA vane 104b to move towards the delay wall 127a, which in turn contributes to the movement of the CTA vane 104a towards the delay wall 103a. Fluid in the OPA feed chamber 125 pressurizes the locking pin line 128, which biases the locking pin 130 against the spring 131 away from the recess 132 and into an unlocked position. Fluid from the OPA retardation chamber 127 exits into the outlet line 122 through the control valve 109 between the slide lobes 111c and 111d and through the line 124.

[0021] "Makeup" oil is fed from the pump 140 to the adjuster to compensate for leaks and enters line 119. Line 119 leads to an inlet check valve 118 and the control valve 109. From the control valve 109, fluid enters line 114 through the feed check valve 108 and flows to the CTA feed chamber 102 and the OPA feed chamber 125.

[0022] By allowing fluid to flow from the CTA retardation chamber 103 to the common line 114 through the feed check valve 108 and filling the CTA feed chamber 102; by blocking the CTA feed chamber 102 before it empties into the outlet line 121 by the slide gate 111a; and by allowing the OPA retardation chamber 127 to empty through the outlet line 122 into the oil pan, the adjuster is caused to move the CTA vane 104a by means of cam torque energy and assistance from engine oil pressure in order to move the OPA vane 104b, so that the adjuster can be actuated by one or both energy sources, cam torque energy or oil pressure energy.

[0023] When the duty cycle is set between 20 and 50%, the actuator's wing moves towards and / or into a delay position.

[0024] Fig. Figure 2 represents the adjuster moving into the deceleration position. To move into the deceleration position, the duty cycle is changed to more than 0% but less than 50%, the force of the VFS 107 on the slide 111 is reduced, and the slide 111 is moved to the left into a deceleration mode by the spring 115 until the force of the spring 115 balances the force of the VFS 107.

[0025] In the depicted delay mode, the slide lift 111d blocks the exit of fluid through the outlet line 122 from the CTA delay chamber 103. Lines 112 and 114 are open to the CTA feed chamber 102 and the CTA delay chamber 103, respectively. A camshaft torque pressurizes the CTA feed chamber 102, causing fluid in the CTA feed chamber 102 to move into the CTA delay chamber 103 and the vane 104a to move towards the feed chamber wall 102a. Fluid exits the CTA feed chamber 102 through the line 112 to the control valve 109 between slide risers 111b and 111c and is returned to the common line 114 and line 113, which leads to the CTA retardation chamber 103.

[0026] Fluid flowing to the CTA retarding chamber 103 also flows through the retarding line 113 and between the slide bar risers 111c and 111d to the OPA retarding chamber 127, thus moving the OPA vane 104b to the feed wall 125a, which in turn contributes to the movement of the CTA vane 104a to the feed wall 102a. Fluid from the OPA feed chamber 125' exits into the outlet line 121 through the control valve 109 between the slide bar risers 111a and 111b and through line 123. As fluid exits the OPA feed chamber 125, pressure is released from the locking pin line 128 and the spring 131 pre-tensions the end section of the locking pin 130 into engagement with the recess 132 of the housing arrangement 100.

[0027] "Makeup" oil is fed from the pump 140 to the adjuster to compensate for leaks and enters line 119. Line 119 leads to an inlet check valve 118 and the control valve 109. From the control valve 109, fluid enters line 114 through the delay check valve 110 and flows to the CTA delay chamber 103.

[0028] By allowing fluid to flow from the CTA feed chamber 102 to the common line 114 through the delay check valve 110 and filling the CTA delay chamber 103; by blocking the CTA delay chamber 102 before it empties into the outlet line 122 by the slide gate 111d; and by emptying the OPA feed chamber 125 through the outlet line 121 into the oil pan, the adjuster is caused to move the CTA vane 104a using cam torque energy and assistance from engine oil pressure to move the OPA vane 104b, so that the adjuster can be actuated by one or both energy sources, cam torque energy or oil pressure energy.

[0029] The holding position of the adjuster is preferably located between the deceleration and the feed position of the wing in relation to the housing.

[0030] Fig. Figure 3 represents the adjuster in the zero or holding position. In this position, the duty cycle of the variable force solenoid 107 is approximately 50%, and the force of the VFS 107 at one end of the slide 111 corresponds to the force of the spring 115 at the opposite end of the slide 111 in holding mode. The protrusions 111b and 111c restrict the fluid flow from the feed line 112, which is connected to the CTA feed chamber 102 and the OPA feed chamber 125, and the fluid flow from the retardation line 113, which is connected to the CTA retardation chamber 103 and the OPA retardation chamber 127. The slide protrusion 111a blocks the outlet line 121, and the slide protrusion 111d blocks the outlet line 122.

[0031] "Makeup" oil is fed from the pump 140 to the adjuster to compensate for leaks and enters line 119. Line 119 leads to an inlet check valve 118 and the control valve 109. From the control valve 109, fluid enters line 114 through the feed check valve 108 to the CTA feed chamber 102 and through the delay check valve 110 to the CTA delay chamber 103.

[0032] The slide valve is arranged such that fluid can flow from the supply through the feed check valve 108 and the delay check valve 110 to the CTA feed chamber 102 and the CTA delay chamber 103, and then to the OPA feed chamber 125 and the OPA delay chamber 127. Fluid in the OPA feed chamber 125 pressurizes the locking pin line 128, which biases the locking pin 130 against the spring 131 away from the recess 132 and into an unlocked position. Since the same pressure is applied to both the OPA feed chamber 125 and the OPA delay chamber 127, the adjuster maintains its position.

[0033] In the second embodiment, which is described in Fig. 4, Fig. 5 to Fig. As shown in Figure 6, the connection to the OPA chambers 125, 127 and the CTA chambers 102, 103 is coplanar and radially separated from each other around the sleeve 116. An advantage of this coplanar and radially separated connection for the OPA chambers 125, 127 and the CTA chambers 102, 103 around the sleeve 116 is that the oil is directed to the OPA chambers 125, 127 and does not have to flow through the feed and delay check valve 108, 110 as in the first embodiment.

[0034] In relation to Fig. 4, Fig. 5 to Fig. In the second embodiment, the housing assembly 100 of the adjuster has an outer circumference 101 for receiving a drive force. The rotor assembly 105 is connected to the camshaft and arranged coaxially in the housing assembly 100. The rotor assembly 105 has at least two vanes, namely a CTA vane 104a and an OPA vane 104b. The CTA vane 104a divides the chamber 117a, which is formed between the housing assembly 100 and the rotor assembly 105, into a CTA feed chamber 102 and a CTA retardation chamber 103. Torque reversals in the camshaft, caused by the forces of the opening and closing engine valves, move the CTA vane 104a. The CTA feed and retardation chambers 102, 103 are designed to withstand positive and negative torque impulses in the camshaft and are alternatively pressurized by the cam torque.The control valve 109 allows the CTA vane 104a to move in the adjuster by allowing a fluid flow from the CTA feed chamber 102 to the CTA deceleration chamber 103 or vice versa, depending on the desired direction of movement.

[0035] The OPA vane 104b separates the chamber 117b, which is formed between the housing arrangement 100 and the rotor arrangement 105, into an OPA feed chamber 125 and an OPA deceleration chamber 127. The OPA vane 104b is assisted by motor oil pressure actuation.

[0036] The vanes 104a, 104b can rotate to shift the relative angular position of the housing assembly 100 and the rotor assembly 105.

[0037] A locking pin 130 is slidably housed in a bore in the rotor assembly 105 and has an end section that is biased by a spring 131 towards a recess 132 in the housing assembly 100 and fits into it. In a locked position, the end section of the locking pin 130 engages in the recess 132 of the housing assembly 100. In an unlocked position, the end section of the locking pin 130 does not engage in the housing assembly 100. Alternatively, the locking pin 130 can be housed in the housing assembly 100 and the spring 131 can be biased towards a recess 132 in the rotor assembly 105.

[0038] In Fig. 4, Fig. 5 to Fig. 6. The pressure on the locking pin 130 is controlled by the fluid in the OPA feed chamber 125 via line 128, which is in fluid exchange with the OPA feed chamber 125. With the locking pin 130, which is controlled by fluid in the OPA feed chamber 125, the adjuster can be locked in the delay position by venting the OPA feed chamber 125, such that the locking pin 130 engages a delay stop. Alternatively, the pressure on the locking pin 130 can be controlled by fluid in the OPA delay chamber 127. With the locking pin 130, which is controlled by fluid in the OPA delay chamber 127, the adjuster can be locked in the feed position by venting the OPA delay chamber 127 in such a way that the locking pin 130 is engaged against a feed stop.

[0039] The CTA feed chamber 102 is connected to the CTA retarding chamber 103 via the feed line 112, retarding line 113, common line 114, the feed check valve 108, the retarding check valve 110, and the control valve 109. The OPA feed chamber 125 is connected to the control valve 109 via the oil pressure feed line 224, and the OPA retarding chamber 127 is connected to the control valve 109 via the oil pressure retarding line 223.

[0040] A control valve 109, preferably a slide valve, has a slide 111 with cylindrical projections 111a, 111b, 111c, and 111d, which are slidably mounted in a sleeve 116. The control valve can be located remotely from the adjuster in a bore in the rotor assembly 105, which controls the camshaft, or in a centering pin of the adjuster. The lengths of the projections 111a, 111b, 111c, and 111d of the slide 111 are such that the CTA chambers 102, 103 to exhaust lines 122, 121 are not open, allowing for venting during the movement of the slide 111. One end of the slider contacts the spring 115 and the opposite end of the slider contacts a pulse-width modulated variable force solenoid (VFS) 107. The solenoid 107 can also be controlled linearly by varying the current or voltage, or by other methods as required.Furthermore, the opposite end of the slide 111 can touch and be influenced by a motor or other actuators.

[0041] The position of the slide 111 is influenced by a spring 115, and the solenoid 107 is controlled by the ECU 106. Further details regarding the control of the adjuster are explained in detail below. The position of the slide 111 controls the movement (e.g., to move to the feed position, the hold position, or the deceleration position) of the adjuster and also controls whether the locking pin 130 is in a locked or unlocked position. The control valve 109 has a feed mode, a deceleration mode, and a hold position.

[0042] Fig. Figure 4 represents the adjuster, which moves to the feed position. To move into the feed position, the work cycle is increased to more than 50%, the force of the VFS 107 on the slide 111 is increased, and the slide 111 is moved by the VFS 107 into a feed mode to the right until the force of the spring 115 balances the force of the VFS 107.

[0043] In the illustrated feed mode, the slide lift 111b blocks the exit of fluid through the outlet line 121 from the CTA feed chamber 102. Lines 113 and 114 are open to the CTA retardation chamber 103. A camshaft torque pressurizes the CTA retardation chamber 103, causing fluid to move from the CTA retardation chamber 103 into the CTA feed chamber 102, and the CTA vane 104a is moved by cam torque energy towards the retardation wall 103a. Fluid exits the CTA delay chamber 103 through line 113 to the control valve 109 between slide risers 111b and 111c and is returned to the common line 114, the feed check valve 108 and line 112, which leads to the CTA feed chamber 102.

[0044] The flow of fluid from line 112 to the CTA feed chamber 102, and through the control valve 109, is prevented by the slide bar lift 111b. In addition to fluid from the supply line 119, fluid exiting the CTA retarder chamber 103 flows into the OPA feed chamber 125, causing the OPA vane 104b to move towards the retarder wall 127a. This movement of the CTA vane 104a is thus assisted by hydraulic pressure energy. Fluid in the OPA retarder chamber 127 exits the chamber through line 223 and through the control valve between the slide bars 111a and 111b into the outlet line 121. Therefore, the adjuster can be actuated by one or both energy sources: cam torque energy or hydraulic pressure energy.

[0045] Fluid in the OPA feed chamber 125 exerts pressure on the locking pin line 128, which biases the locking pin 130 against the spring 131 away from the recess 132 and into an unlocked position.

[0046] "Makeup" oil is fed from the pump 140 to the adjuster to compensate for leaks and enters line 119. Line 119 leads to an inlet check valve 118 and the control valve 109. From the control valve 109, fluid enters line 114 through the feed check valve 108 and flows to the CTA feed chamber 102.

[0047] When the duty cycle is set between 0 and 50%, the actuator's wing moves towards and / or into a delay position.

[0048] Fig. Figure 5 represents the adjuster moving into the deceleration position. To move into the deceleration position, the duty cycle is changed to more than 0% but less than 50%, the force of the VFS 107 on the slide 111 is reduced, and the slide 111 is moved to the left into a deceleration mode by the spring 115 until the force of the spring 115 balances the force of the VFS 107.

[0049] In the depicted delay mode, the slide lift 111c blocks the outflow of fluid through the outlet line 122 from the CTA delay chamber 103.

[0050] Lines 112 and 114 are open to the CTA feed chamber 102. A camshaft torque pressurizes the CTA feed chamber 102, causing fluid in the CTA feed chamber 102 to move into the CTA retardation chamber 103. The camshaft torque energy then moves the vane 104a towards the feed chamber wall 102a. Fluid exits the CTA feed chamber 102 through line 112 to the control valve 109 located between the slide gates 111b and 111c, and is returned to the common line 114, the retardation check valve 110, and line 113, which leads to the CTA retardation chamber 103.

[0051] The flow of fluid from line 113 to the CTA retarding chamber 103, and through the control valve 109, is prevented by the slide bar lift 111c. In addition to fluid from the supply line 119, fluid exiting the CTA feed chamber 102 flows into the OPA retarding chamber 127, causing the vane 104b to move towards the feed wall 125a. This movement of the CTA vane 104a is assisted by oil pressure energy. Fluid in the OPA feed chamber 125 exits through line 224 and the control valve between the slide bars 111c and 111d into the outlet line 122 and into the oil pan. Therefore, the adjuster can be actuated by one or both energy sources: cam torque energy or oil pressure energy.

[0052] When fluid exits the OPA feed chamber 125, pressure is released from the locking pin line 128 and the spring 131 pre-tensions the end section of the locking pin 130 into engagement with the recess 132 of the housing arrangement 100.

[0053] "Makeup" oil is fed from the pump 140 to the adjuster to compensate for leaks and enters line 119 through a bearing 120. Line 119 leads to an inlet check valve 118 and the control valve 109. From the control valve 109, fluid enters line 114 through the delay check valve 110 and flows to the CTA delay chamber 103.

[0054] The holding position of the adjuster is preferably located between the deceleration and the feed position of the wing in relation to the housing.

[0055] Fig.Figure 6 represents the adjuster in the zero or holding position. In this position, the duty cycle of the variable force solenoid 107 is approximately 50%, and the force of the VFS 107 at one end of the slide 111 corresponds to the force of the spring 115 on the opposite end of the slide 111 in holding mode. The protrusions 111b and 111c block the exit of fluid from the CTA feed chamber 102 and the CTA retardation chamber 103. The same protrusions 111b and 111c also allow fluid from the supply line 119 to flow into the lines 223 and 224 to the OPA retardation chamber 127 and the OPA feed chamber 125 through enlarged connection openings in the sleeve 116. The slide lift 111b blocks the outlet line 121 and the slide lift 111c blocks the outlet line 122. Since the same pressure is applied to both the OPA feed chamber 125 and the OPA retarding chamber 127, the adjuster retains its position.

[0056] "Makeup" oil is fed from the pump 140 to the adjuster to compensate for leaks and enters line 119 through a bearing 120. Line 119 leads to an inlet check valve 118 and the control valve 109. From the control valve 109, fluid enters line 114 through the feed check valve 108 and into the CTA feed chamber 102, and through the retardation check valve 110 into the CTA retardation chamber 103.

[0057] Accordingly, it will be understood that the embodiments of the invention described herein are purely illustrative of the application of the principles of the invention. References herein to details of the illustrated embodiments are not intended to limit the scope of protection of the claims in any way, which themselves describe the features that are essential to the invention.

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