Abstract: A camshaft phaser, including: a first surface facing in a first axial direction; and a connection portion extending from the first surface in the first axial direction. The connection portion includes a wall with a second surface facing in a second axial direction, a first circumferentially disposed wall connected to the wall, a second circumferentially disposed wall connected to the wall, a first tab directly connected to the first circumferentially disposed wall and the second circumferentially disposed wall and extending radially outwardly past the first circumferentially disposed wall and the second circumferentially disposed wall, and a plurality of connected groove walls extending from the second surface into the wall in the first axial direction and bounding a reinforcing groove in the wall. At least a portion of the plurality of connected groove walls is located between the first circumferentially disposed wall and the second circumferentially disposed wall.

Abstract: A camshaft adjuster (1) including a stator (2) and a rotor (4), a spring (6) tenses the rotor (4) rotationally counter to the stator (2). According to the invention, the spring is a coil spring (6), the stator (2) includes a first recess (8) of a first free end (10) of the coil spring (6) and the rotor (4) includes a second recess (12) for a second free end (14) of the coil spring (6).

Abstract: A device and method for adjusting a fuel supply advance angle of a multi-cylinder diesel engine includes a gear chamber, a connecting disc and a fuel pump, wherein the gear chamber and the connecting disc are in the diesel engine, and the fuel pump is at a left end surface outside the gear chamber. A main shaft end of the fuel pump extends into the gear chamber. A right end surface of the connecting disc connects to a timing gear. A right end surface of the timing gear has three penetrating circular-arc waist-shaped holes. Annular sizing blocks are arranged on the waist-shaped holes. A penetrating circular hole is at a tail end of the waist-shaped holes. The circular hole is provided with a T-shaped nut. A support screw is arranged in the T-shaped nut, and the screw head of the support screw is jacked against the annular sizing block.

Abstract: An internal combustion engine including: an even number of inline cylinders, each accommodating a piston; a crankshaft rotatably mounted about an axis; first and second balance shafts rotatably mounted about balancing axes parallel to and separate from the engine axis; and first and second mechanisms for rotating the first and second balance shafts at rotating speeds that are dependent on a rotating speed of the crankshaft. The balancing axes of the first and second balance shafts coincide, and the second rotating mechanism adjusts a phase difference between angular positions of the first and second balance shafts around the balancing axis.

Abstract: A sleeve is retained to a shaft without the use of a keyway through at least one end connection that has a preferably flat face with one or more projections from the flat face. Rounded projections are preferred. The projections go into shape matching depressions on the sleeve. Alternatively the sleeve can have the projections and the end retainer can have the depressions. The end retainer is spring loaded for axial deflection in the event of an over-torque. If that happens there is planned for slippage until the condition is alleviated at which point the spring bias is able to again match a projection to a depression for continuing tandem driving of the shaft and the sleeve. The sleeve is preferably carbide and resides in a carbide bushing.

Abstract: A sleeve is retained to a shaft without the use of a keyway through at least one end connection that has a preferably flat face with one or more projections from the flat face. Rounded projections are preferred. The projections go into shape matching depressions on the sleeve. Alternatively the sleeve can have the projections and the end retainer can have the depressions. The end retainer is spring loaded for axial deflection in the event of an over-torque. If that happens there is planned for slippage until the condition is alleviated at which point the spring bias is able to again match a projection to a depression for continuing tandem driving of the shaft and the sleeve. The sleeve is preferably carbide and resides in a carbide bushing.

Abstract: A centrifugal advance mechanism has drive and driven members connected with one another to rotate about a common axis as they move toward and away from each other along the common axis. A resilient element biases the members toward each other. A ramp on one of the members has an inner end portion and an outer end portion. The inner end portion is closer to the common axis than the outer end portion, the ramp rising as it moves from the inner end portion toward the outer end portion. A ba1l contacts the ramp and the other member. The resilient element biases the ball down the ramp, the ball traveling radially outward and up the ramp as the members rotate at increasing angular velocity thereby causing the members to separate from each other against the bias of the resilient element and to rotate with respect to each other.

Abstract: A cam phaser assembly may include a drive plate assembly, a cavity plate, and a driven plate assembly. The drive plate assembly may include a drive plate and a first vane fixed for rotation with the drive plate. The cavity plate may be rotationally driven by the drive plate and may define first and second chambers. The first vane may extend into the first chamber. The driven plate assembly may be rotationally driven by the drive plate assembly and may include a driven plate and a second vane fixed for rotation with the driven plate that extends into the second chamber.

Abstract: An engine assembly may include an engine structure, a crankshaft, a camshaft, a balance shaft, and first and second gears. The crankshaft, camshaft, and balance shaft may each be rotatably supported by the engine structure. The camshaft may be rotationally driven by the crankshaft and the first gear may be coupled to the camshaft. The second gear may be fixed for rotation with the balance shaft and meshingly engaged with and driven by the first gear.

Abstract: A camshaft phaser for an internal combustion engine includes a driven hub attached to a camshaft, and a drive sprocket journaled to the driven hub. A locking device uses a pin receptacle having a locking bore and an engagement ramp which is contiguous with the locking bore to allow a locking pin to extend partially from its housing pin bore before the locking pin is registered with the locking bore.

Abstract: A camshaft phasor control system for an engine includes a position control module. The position control module generates a position control signal based on a camshaft position command signal and a gain signal. A gain circuit generates the gain signal based on the position control signal and feeds the gain signal back to the position control module. The position control module positions a camshaft of the engine based on the gain signal.

Abstract: The present invention provides a variable valve timing device for an internal combustion engine having a double camshaft. A gas exchange valve control shaft is provided which has first and second concentrically arranged cam shafts that are adjustable in a rotatable manner with respect to each other, by which a cam of the first cam shaft is adjusted in terms of its angle towards a cam of the second cam shaft. A cam phasing device is provided which operates by rotatable vanes provoking a swivelling relative movement between a driven member and an output member. The cam phasing device comprises at least two pivotable vane adjusters. Each pivotable vane adjuster is assigned to one of the two cam shafts. The pivotable vane adjusters are arranged axially one after the other in a direction of a valve control shaft. Each pivotable vane adjuster may be designed as a rotor-type vane adjuster.

Abstract: During assembly of an improved phaser, a rotor bias spring is captured by a spring retainer that is fitted or formed into the cover, allowing the spring to be installed in a pre-load position and forming a sub-assembly that is then attached to the remaining components. Grounded and active spring tangs are captured in separate slots in the spring retainer. A pocket within the rotor receives the active tang of the bias spring. The pocket has a tapered bottom ramp that lifts the active tang from the slot wall in the retainer and positions the active tang within the pocket in a retarding direction. Lifting the active tang of the bias spring prevents friction between the spring and the retainer slot wall as would occur as the rotor moves in a retarded direction. In advancing, spring rotation stops when the active tang contacts the end of the retainer slot.

Abstract: An engine equipped with an adjustable valve timing mechanism includes: an inlet valve opening term varying mechanism, which is included in the adjustable valve timing mechanism, varying an opening term of an inlet valve; and an inlet valve opening term controller controlling the inlet valve opening term varying mechanism according to a running state of the engine, the inlet valve opening term varying mechanism setting the opening term of the inlet valve to an first inlet term while the engine runs at relatively high load and relatively high speed, the inlet valve opening term varying mechanism also setting the opening term of the inlet valve to a second inlet term, termination timing of the inlet valve opening of which is retarded compared to the termination timing of the inlet valve opening in the first inlet term, while the engine runs at relatively low load and relatively low speed.

Abstract: A die cast aluminum front cover plate for application in a vane-type camshaft phaser includes a plurality of bores and a plurality of steel threaded inserts press fitted into the bores. Steel threaded inserts add the required strength to the stator bolt threads to enable a shorter thread engagement, which in turn enables a thinner aluminum front cover plate that may be packaged in tight applications where prior art aluminum front covers cannot be used due to their larger thickness. The steel threaded inserts not only provide a higher stiffness but also have a flanged shape that effectively spreads the clamp load generated during the tightening of the stator bolts further out preventing local clamp load points and, consequently, reducing cover deflection over the span of the front cover plate.

Abstract: A camshaft adjuster (1), in which an adjustment of the camshaft adjuster is limited by a limiting element (11) is provided. The limiting element (11) is connected by an eccentric to the associated component (3), in particular, to an inner rotor. By use of an eccentric adjustment of the limiting element, the position of the limiting element in the peripheral direction can be adapted according to the production conditions within the tolerance range. In this way, the mounting of the camshaft adjuster is simplified and the achievable accuracy of the limiting position is improved.

Abstract: A valve timing control device includes a drive pulley driven by a crankshaft of an engine, and a driven camshaft. The camshaft has a cam that serves to open and close an intake port. An engine valve is spring-loaded by a valve spring, whereas the cam opens or closes the engine valve against the bias of the spring. Torque is transmittable between the drive pulley and the camshaft, and a rotation angle adjusting mechanism is provided therebetween. The rotation angle adjusting mechanism has a movable operating member being movable in a substantially radial direction.

Abstract: In an adjusting device for an internal combustion engine, in particular a camshaft adjusting device, an adjusting unit is provided which comprises at least one currentless sensor unit for carrying out in at least one mode an adjustment as a function of a momentary phase angle between cooperating relatively rotatable members.

Abstract: A locking unit of a camshaft adjuster (1) for an internal combustion engine is provided, in which a locking pin (19) establishes a positive connection between a driving element and a driven element of the camshaft adjuster (1). The driving element and/or the driven element are formed by a plastic part. An insert (26) against which the locking pin (19) rests and which is supported relative to the plastic part in the area of an inner and outer contour is inserted into the plastic part. Providing large area support of the contours makes it possible to use plastic as a material in spite of the great stress that occurs, particular attention being paid to a good introduction of force into the plastic part.

Abstract: A device for variably setting the control times of gas exchange valves of an internal combustion engine is provided having a hydraulic actuator (18) with two reciprocally operating pressure chambers (12, 13) and with a pressure medium supply device (32) for supplying and withdrawing pressure medium to or from the pressure chambers (12, 13). The device (1) also includes at least one rotation angle limiting device (24) that in an unlocked state does not limit the phasing of the output element (3) in reference to the input element (2) but, in a locked state, limits it to a defined angular range or to a defined angle, with the rotation angle limiting device (24) being switched from the locked to the unlocked state by pressure medium being supplied. A control line (19) is provided for supplying and withdrawing pressure medium to or from the rotation angle limiting devices (24), with the control line (19) not communicating with the pressure medium supply device (32).

Abstract: A device (1) for the variable adjustment of control times of an internal combustion engine, including a stator (2), a driven element (3) arranged coaxially thereto, with both components being assembled so as to rotate relative to one another, and both components define at least one pressure chamber (10) at least in the radial and circumferential directions, and a housing (11), separate from the stator (2) and the driven element (3) which encloses the stator (2) and the driven element (3) in an oil-tight manner, whereby the housing (11) seals and defines the pressure chamber in an axial direction.

Abstract: In a variable valve unit provided with a variable valve mechanism that varies opening characteristics of an engine valve by rotary motion of a control shaft, an actuator that generates a rotary motion of the control shaft, a stopper restricting the rotary motion of the control shaft, and an angle sensor capable of outputting signals corresponding to angle positions of the control shaft, when the signal of the angle sensor at an angle position where the rotation of the control shaft is restricted by the stopper are learned, the actuator is controlled such that the control shaft is pressed against the stopper, after which drive torque of the actuator is reduced and with the drive torque reduced, signals of the then-angle sensor are stored.

Abstract: In a camshaft adjusting device for an internal combustion engine, wherein the adjustmen device includes a brake unit which has at least one eddy-current brake for generating a braking torque (Mb) which correlates with a phase angle of a camshaft, a supplementary unit is provided to at least supplement the eddy-current brake with respect to its adjusting function in at least one operating range.

Abstract: In a first embodiment of a camshaft phaser, the rotor is split along an equatorial plane thereof, defining first and second rotor portions. A resilient seal is compressively disposed between the rotor portions to prevent leakage therebetween and to urge the rotor vanes against the cover plate and sprocket surfaces to prevent leakage around the vanes. Preferably, the seal includes radial seal elements to seal against the stator wall. Preferably, pressurized hydraulic fluid can enter between the first and second rotor portions and thereby assist the resilient seal in urging the rotor portions apart. In a second embodiment, the rotor is not split, and a resilient seal is provided on at least one axial face of the rotor vanes to seal the rotor vanes against the cover plate and sprocket surfaces.

Abstract: A valve timing controller of an engine reduces degradation of drivability such as a feeling of jumping out of a vehicle and achieves a rapid increase in engine output according to a throttle operation amount. An ECU shifts a phase of a cam shaft toward a control target value A at a reference update speed C1 when it is judged that a rider does not desire an output increase, and shifts the phase of the cam shaft toward the control target value A at a transient update speed C2 higher than the reference update speed C1 when it is judged that the rider desires an output increase.

Abstract: A valve timing controller has a shaft body as an output rotor, a torque generating system which generates the controlling torque outputted from the shaft body, and a planet carrier as an input rotor connected with the shaft body. A phase adjusting mechanism adjusts the relative rotational phase between a crankshaft and a camshaft according to the control torque inputted into the planet carrier from the shaft body. A bearing rotatably supports the planet carrier. The planet carrier forms a cylindrical input wall press-inserted in an inner circumference of the bearing. The input wall is provided with a fitting recess on its inner surface for engaging with the shaft body, the input wall is provided with a thin-wall portion of which thickness is reduced in a radial direction, and the fitting recess and the thin-wall portion are circumferentially arranged apart from each other.

Abstract: A valve timing system for an internal combustion engine includes a phase alteration mechanism interposed between a driving rotator and a driven rotator and having a direction turning point at which the phase alteration direction is reversed when a movable portion of the mechanism travels from a beginning to a termination, and an operation control device for displacing the movable portion when undergoing an energization control, the movable portion being displaced toward the beginning when the energization control fails to be carried out. The rotation phase is set at a middle position between a maximum retard position and a maximum advance position when the movable portion is located at the beginning.

Abstract: An abnormality diagnosis system 100 includes a VVT controller 110, an adjustable valve mechanism 120, a cam angle sensor 130, a model computation module 140, an abnormality detection module 150, and an alarm lamp 160. The adjusable valve mechanism 120 advances or delays a phase angle of an intake cam shaft relative to a crankshaft, thereby varying an open-close timing of a valve. The model computation module 140 computes a physical behavior of the adjustable valve mechanism 120 according to a physical model, in response to a control signal input from the VVT controller 110. The abnormality detection module 150 determines whether the adjustable valve mechanism 120 is abnormal or normal, based on a difference between a theoretical value of phase angle calculated according to the physical model and an observed value of phase angle measured with the cam angle sensor 130. The arrangement of the invention ensures highly accurate abnormality diagnosis of the adjustable valve mechanism 120.

Abstract: Camshaft adjusters according to the swivel motor principle may be provided with a bar which arrests the rotor in a position relative to the stator. A bar according to the invention is provided with two portions, between which a change of power transmission takes place during the arresting process.

Abstract: A valve timing control apparatus includes a driving side rotational member, a driven side rotational member formed with a plurality of recessed portions into which a supporting jig is insertable at a second side thereof in the axial direction, a fluid pressure chamber, a vane, a lock member, and a cover plate formed with a plurality of through holes, through which the supporting jig is insertable, at a position in which each of the plurality of through holes is overlapped with each of the plurality of recessed portions of the driven side rotational member in a condition where the relative rotational phase is restrained at the lock phase.

Abstract: A twin vane-type phaser is described which is provided with a locking mechanism for locking the drive member to the driven members when the pressure in the working chambers is a below is predetermined value. The locking mechanism comprises two coaxial locking pins 114, 118 mounted in a common bore 110 in the centrally located member 32. The locking pins are resiliently urged apart by a spring 120 into bores in the two outer members 38, 40 and are retracted by pistons 112, 116 when the hydraulic pressure in the working chambers attains the predetermined value.

Abstract: To operate a steplessly adjustable camshaft control device, particularly reliably and safely, an adaptation of the camshaft and the crankshaft is performed so that a phase angle (actual value) of the camshaft to the crankshaft is determined, the phase angle is monitored while operating the internal combustion engine and the camshaft control device is controlled as a function of a variable setpoint value so that the phase angle is equivalent to the setpoint value.

Abstract: A valve timing control apparatus for controlling an opening and closing timing of a valve of an internal combustion engine includes a driving side rotational member synchronously rotated with a crankshaft, a driven side rotational member provided coaxially with the driving side rotational member and synchronously rotated with a camshaft, a fluid pressure chamber being separated into an advanced angle chamber and a retarded angle chamber, a phase control apparatus for displacing a relative rotational phase between the driving side rotational member and the driven side rotational member, a locking mechanism having a movable member, a judging device for judging a supply condition of the operation fluid relative to the fluid pressure chamber, and a control device for controlling a rotational speed of the crankshaft.

Abstract: A camshaft is formed at a generally middle portion with an enlarged cylindrical portion. An annular vane member is mounted on the enlarged cylindrical portion and secured thereto by means of a nut. An annular housing or sprocket is arranged to receive therein the annular vane member in a manner to permit a rotation of the vane member relative to the annular housing. Each of a circular opening of the vane member and a circular opening of the annular housing is so sized as to permit cam lobes of the camshaft to pass therethrough.

Abstract: A control structure for the adjusting motor of an electric camshaft adjuster in an internal combustion engine is provided. The control structure includes a controller which processes measuring signals of the internal combustion engine to control data for the adjusting motor. A controller which has meaningful values for the adjusted setpoint rotational speed of the adjusting motor, even when the input differential signal has a zero value, is obtained by applying the signal of an uncontrolled rotational speed to the output signal of a controlled setpoint rotational speed.

Abstract: The invention intends to improve a response by utilizing a rotational variable torque of a cam shaft. Communication paths respectively communicating an advance hydraulic chamber and a retard hydraulic chamber provided in a second rotary member and a hydraulic connecting passage are provided so as to be communicated, at a time when a control member intending to improve a response by moving a phase angle control slider in an axial direction or a rotational direction in correspondence to an operating state such as an advance, a retard or the like so as to intermittently communicate an advance chamber communication path and a retard chamber communication path with a hydraulic chamber connecting groove only in a section in which a cam shaft variable torque in an operating direction is applied, is controlled in a rotating region, and a relative rotation of a third rotary member and the second rotary member stops.

Abstract: A device for adjusting a camshaft of an internal combustion engine of a motor vehicle has a stator and a rotor fixedly connected to a camshaft and rotatable relative to the stator. A drive wheel is fixedly connected to the stator and is centered by the camshaft. The stator has a peripheral area provided with a centering element interacting with a counter element provided on the drive wheel for aligning the drive wheel in a rotational direction relative to the stator.

Abstract: In a hydraulic camshaft adjuster for an internal combustion engine including a hydraulic operating unit for adjusting the angular position of the camshaft relative to a camshaft drive by way of a hydraulic control valve with a valve housing in which a control piston is disposed for controlling the supply of hydraulic fluid to, and its removal from, the hydraulic operating unit and to which hydraulic fluid is supplied from the camshaft by way of a pressure channel which is formed into the valve housing so as to extend along the outer surface thereof and a sleeve tightly surrounds at least the part of the valve housing which includes the channel for tightly covering the channel.

Abstract: A variable camshaft timing phaser for an internal combustion engine having at least one camshaft comprising a plurality of vanes in chambers defined by a housing and a spool valve. The vanes define an advance and retard chamber. At least one of the vanes is cam torque actuated (CTA) and at least one of the other vanes is oil pressure actuated (OPA). The spool valve is coupled to the advance and retard chamber defined by the CTA vane and the advance chamber defined by the OPA vane. When the phaser is in the advance position, fluid is routed from the retard chamber defined by the OPA vane to the retard chamber defined the CTA vane. When the phaser is in the retard position fluid is routed from the retard chamber defined by the CTA vane to the advance chamber defined by the CTA vane.

Abstract: A region including an engaging hole is given surface treatment such as partial quench hardening by induction hardening for improving surface hardness of the region. The partial quench hardening by induction hardening provides the region with satisfactory mechanical strength or surface hardness enough for resisting deformation of the engaging hole and wear-out of an edge of opening of the engaging hole caused by putting in and out of the lock pin.

Abstract: In an oil flow control valve (OCV) according to the present invention, a first volume varying chamber is adapted to communicate with a second volume varying chamber through a second plunger breathing path, and the second volume varying chamber is adapted to communicate with a first breathing hole through an intra-plunger breathing path, an intra-shaft breathing path, and a third volume varying chamber. That is, the breathing path to the second volume varying chamber is long and the volume thereof is large, and the breathing path to the first volume varying chamber is still longer and larger in its volume. Consequently, the amount of foreign matters getting into the first and second volume varying chambers can be decreased and therefore it is possible to prevent the occurrence of an operation defect of the OCV.

Abstract: A variable valve timing control device comprises a housing member integrally rotating with either one of a crankshaft or a camshaft of an internal combustion engine, a rotor member assembled to the housing member so as to be rotatable relative thereto, including at least one of vane portions forming an advanced angle chamber and a retarded angle chamber within the housing member, and integrally rotating with the other one of the crankshaft or the camshaft; a fluid pressure circuit for controlling operation fluid to be supplied to or discharged from the advanced angle chamber and the retarded angle chamber, an engaging groove formed at the housing member in circumferential direction and including an advanced angle side end portion and a retarded angle side end portion, a lock member provided at the housing member and being freely projecting/retreating, and a projecting portion provided at the rotor member and projecting outward, which is sandwiched between either one of the end portions of the engaging groove

Abstract: A camshaft adjuster for internal combustion engines of motor vehicles has a stator having a casing and stays connected to the casing and projecting radially inwardly. A rotor rotatable relative to the stator is fastened on the camshaft. The rotor has a rotor base member and vanes connected thereto. The vanes project into spaces between the stator stays. The stays each have an end face that rest sealingly against the rotor base member. The vanes of the rotor each have an end face resting sealingly against an inner peripheral wall of the stator. At least one of the vanes of the rotor has a damping element and the stator has at least one counter damping element. Upon rotation of the rotor into its end position, the damping element interacts with the counter damping element and slows the movement of the rotor into the end position.

Abstract: A valve timing control device for an internal combustion engine, comprises a drive rotary member rotated by a crankshaft of the engine, a driven rotary member to rotate a camshaft of the engine upon rotation of the drive rotary member; a rotational phase control mechanism having an intermediate rotary member rotated relative to the drive and driven rotary members to cause relative rotation between the drive and driven rotary members and an braking mechanism having a hysteresis brake that generates a braking force to cause the intermediate rotary member to rotate relative to the drive and driven rotary members.

Abstract: A valve timing adjusting device sets an amount of phase shift of a driven shaft with respect to a drive shaft. A first hole in a first rotor forms a first track extending in order to vary its radial distance from a rotation center line. The first hole makes contact with a control member passing through the first track, on the two sides of the first hole toward which the first hole (the first rotor) rotates. A second hole in a second rotor forms a second track that extends. The second hole makes contact with the control member that passes through the second track. The first track and the second track slant toward each other in the rotation direction of the first and second rotor.

Abstract: A variable valve timing apparatus for vehicle engine, the apparatus comprising: a rotor secured at a tip end of a cam shaft; a housing with the rotor rotatably mounted therein; and a piston mounted in the housing for rotating the rotor, such that the number of oil pressure chambers and seals is reduced to improve tightness of the oil pressure chambers and friction area is also reduced to decrease the consumed driving oil pressure.

Abstract: In a valve timing adjusting apparatus, rotating response speed of a vane rotor and a moving speed of a lock piston are changed according to changes of oil temperature and pressure. It sometimes happens that the lock piston passes the fitting hole before the lock piston is fitted in the fitting hole. Timing of actuating a solenoid valve is retard by a given delay time from timing of actuating a spool valve. The given delay time is decided by a map based on sensor signals representing the oil temperature and pressure input to ECU. The given delay time is shorter as the oil temperature increases and longer as the oil pressure increases.

Abstract: A variable valve timing device includes a rotation transmitting member rotated integrally with a rotation shaft of an engine, a rotor member disposed in the rotation transmitting member to be rotated relative to the rotation transmitting member and rotated integrally with an intake and exhaust valves controlling member, a fluid chamber defined between the rotor member and the rotation transmitting member, a vane radially equipped to one of the rotor member and the rotation transmitting member, and a covering member fixed to the rotation transmitting member for covering the fluid chamber. An axial edge surface of the biasing member discontinuously comes in contact with at least one of the rotor member and the covering member.

Abstract: A valve timing control device is provided, which has an advantageous point of locking a relative rotation phase at an intermediate phase based on an engine halt signal. The valve opening-closing timing control device has a relative rotation control mechanism including the first path for supplying or discharging oil to or from the retard angle chamber and the advance angle chamber and for moving a relative rotation phase between the retard angle chamber and the advance angle chamber in the range between the most retarded angle phase and the most advanced angle phase. The relative rotation control mechanism has a lock oil passage for actuating lock portions for locking the relative rotation phase at the intermediate phase between the most retarded angle phase and the most advanced angle phase. The second path is provided separately from the first path. The second path supplies oil to and discharges oil from a lock oil passage.

Abstract: In a variable valve timing mechanism that changes a rotation phase of a camshaft with respect to a crankshaft by an actuator to vary valve timing of engine valves, when a fixed condition of the rotation phase is detected, the actuator is forcibly driven, to generate a torque alternately in an advance direction and a retarded direction of the rotation phase.