Abstract: A valve timing control device includes a rotary member rotatably arranged in a torque transmitting route between a crankshaft and a camshaft of an internal combustion engine, a rotational transmitting member rotatable relative to the rotary member, a pressure chamber formed by the rotary member and the rotational transmitting member, a vane provided on the rotary member or the rotational transmitting member to divide the pressure chamber between an advancing chamber and a delaying chamber, a helical spring having a coil portion, a first end portion engaging the rotary member, and a second end portion engaging the rotational transmitting member to urge the rotary member in the advancing direction to expand the advancing chamber. One of the end portions of the helical spring extends on an imagined radial plane arranged in the radial direction of the coil portion.

Abstract: In a low rotation region of an engine, valve timing of two intake valves is advanced and also one of two exhaust valves is driven by means of a cam with valve lift lower than that of the other exhaust valve, to thereby set a valve overlap period within which only one of the two exhaust valves is opened.

Abstract: A valve timing control apparatus has a variable valve timing actuator. The system advances the valve timing to at least a middle position before the engine is completely stopped. The middle position is appropriate to start the engine. Before stopping the engine, if the oil temperature is too high to maintain a viscosity, the system provides a control to assist the above-described advancing control. For instance, the system increases the engine speed to supply a sufficient amount and pressure of oil. The system slightly advances the valve timing while the engine is in an idling.

Abstract: A valve control mechanism for an internal combustion engine is disclosed which includes a camshaft carrying a plurality of cams, the cams cooperating with and thereby serving to actuate valves which control the induction of fluids into, and the exhaust of fluids from, a combustion cylinder during the operating cycle of the engine; wherein:

Abstract: A hydraulic camshaft adjusting device, which comprises a drive wheel (2) and a pivotal impeller wheel (10) connected in a rotationally fixed manner to a camshaft (9), the drive wheel (2) comprises a. cavity formed by a peripheral wall (3) and two lateral walls, in which cavity at least one hydraulic working space (8) is formed by at least two delimitation walls (7) and the pivotal impeller wheel (10) has at least one radial blade (12), and with each blade (12) divides a hydraulic working space (8) into two hydraulic pressure chambers (13, 14), which are sealed off from one another by sealing elements (17) disposed between the drive wheel (2) and the pivotal impeller wheel (10), the pivotal impeller wheel (10) can be mechanically coupled to the drive wheel (2) in a preferred basic position, a locking element (18) disposed on the drive wheel (2) being movable by a spring clement (19) into a complementary seating (20) in the drive wheel (2).

Abstract: A variable valve timing controller has a housing having a hole in its surface facing a vane rotor. A fitting ring is press-fitted into the hole. A stopper piston prevents relative rotation between the vane rotor and the housing by engaging with the fitting ring. The hole is formed with a part non-contacting with the fitting ring near a through hole, in which a camshaft is inserted, of the housing. Since the fitting ring is apart from the inner surface of the non-contacting part when the fitting ring is press-fitted, little or no stress arises around the non-contacting part near the through hole. Therefore, deformation of the through hole is prevented and sliding friction between the inner periphery of the through hole and the camshaft is minimized.

Abstract: A valve timing control device is mounted on an end of a camshaft having a plurality of cams opening and closing an intake or exhaust valve of an internal combustion engine to modify timing for the opening and closing of the intake or exhaust valve by way of a tappet. The device includes a bias means biasing the camshaft in an advanced direction with a biasing force approximately equal to or smaller than a peak value of frictional torque produced between a cam of the camshaft and the tappet.

Abstract: The present invention provides an actuator assembly for operating a cylinder valve of an internal combustion engine. The actuator assembly achieves fast response times by utilizing a solenoid actuator that contains an armature element formed of a powder metal. A valve system that utilizes two of the actuator assemblies in conjunction with a cylinder valve is also provided.

Abstract: The invention relates to an actuator (5) which is impinged by a force in one end position and is displaced into the other end position by an adjusting device (54) that is controlled using a pulse duration modulated signal. According to said invention, if a quasi-stationary condition is identified, in which despite repeated control intervention the actual position of the actuator lies outside a targeted range around the desired position, the retaining pulse duty factor which is used by the adjusting device (54) to maintain the actuator (5) in one position is modified based on the distance from the desired position. If a drift is identified, the drift behaviour is determined and the retaining pulse duty factor is modified according to said drift behaviour.

Abstract: In a VVA apparatus, when an actual lift amount detected by a lift-amount detecting sensor exceeds a basic lift-amount target value by a predetermined value or more, ECU corrects a lift phase through a lift-phase varying mechanism to separate from a piston TDC with respect to a basic lift-phase target value.

Abstract: The cam face of an intake cam has a main lift portion, which causes an intake valve to execute a basic lift operation, and a sub lift portion, which assists the action of the main lift portion. The main lift portion and the sub lift portion continuously change in an axial direction of the intake cam. An axial movement mechanism moves the intake cam in the axial direction to adjust the axial position of the cam face that drives the intake valve. The axial movement of the intake cam results in the valve being given a variety of valve lift characteristics in the form of a combination of a cam lift pattern realized by the main lift portion and a cam lift pattern realized by the sub lift portion. Therefore, various engine performances required according to the running conditions of the engine can be fully satisfied by the valve characteristics.

Abstract: A camshaft drive mechanism for a vee-twin engine is described. The mechanism comprises first and second camshafts which are driven by a gear on the crankshaft of an engine incorporating the mechanism. The crankshaft drive gear engages a primary (idler) gear on the first camshaft while a secondary gear on that camshaft imparts counter rotation on the second camshaft via an identical secondary gear on the latter camshaft.

Abstract: The present invention relates to an apparatus for adjusting a camshaft of an internal combustion engine with at least one electromotor which produces, by way of a planetary gear, the adjustment of the camshaft with respect to a pinion, with the planetary gear comprising a first ring gear and a second ring gear as well as at least a first planet wheel which is in engagement with the first ring gear and at least a second planet wheel which is in engagement with the second ring gear and which is rigidly connected with the first planet wheel.

Abstract: A system for controlling the timing of a cylinder valve in a reciprocating internal combustion engine includes a crankshaft position sensor for determining position of the crankshaft, and a camshaft structural force sensor for determining the presence of a structural force upon the camshaft related to a unique rotational position of the camshaft. A controller receives position signals from the crankshaft and camshaft structural force sensors. The controller compares the valve position signal from the structural force sensor with a predicted valve position based upon the crankshaft position and determines if the predictive value is in error. If an error is greater than a specified threshold, the predictive model will be corrected.

Abstract: An internal combustion engine is disclosed. The engine includes a camshaft carrying a plurality of cams, the camshaft being mounted in a cylinder head or cam carrier; and a valve control mechanism comprising: (a) first means for effecting a limited degree of axial movement of the camshaft; and (b) second means for varying the rotational phase of said camshaft, characterised in that said first and second means comprise a pair of concentric pistons housed within a cylinder and under independent hydraulic control, whereby the concentric pistons can be moved independently of one another. This arrangement enables the valve lift, duration and timing to be varied when the camshaft carries 3-D profiled cam lobes (i.e. valve lift varies tangentially with cam angle in end view and varies along the camshaft linearly at each cam angle in side view).

Abstract: The invention describes a rocker arm displacement system for variable valve timing in internal combustion engines. More specifically, the system provides a rocker arm displacement system including a rocker arm having a pivot, a cam-contacting portion and a valve stem contacting portion and a linear displacement system for linear displacement of the cam-contacting portion with respect to a variable profile cam.

Abstract: A valve timing control apparatus for an internal combustion engine is capable of ensuring good response within a control range, stability outside the control range, and durability without increasing the capacity of electric power for a drive circuit and an OCV coil. The valve timing control apparatus includes an intake vale 31, an exhaust valve 32, an engine operating condition detecting section (3, 11, 14), a target valve timing calculating section 21, variable valve timing mechanisms 15, 16, an actual valve timing detecting section (14, 17, 18), a control amount calculating section 21 for calculating a control amount based on target valve timing, actual valve timing and engine operating conditions, and an actual valve timing control section (19, 20) for outputting the control amount as an output control amount to the variable valve timing mechanisms.

Abstract: In a variable valve timing system for an internal combustion engine, a soft-landing revertive control that an electromagnetic brake is de-energized and then an angular position of a camshaft relative to a crankshaft returns to an initial position is performed by a combination of a feedback control and a feedforward control. During the revertive control, the feedback control is executed in such a manner as to temporarily halt the angular phase of the camshaft at a predetermined position, which is phase-changed by a predetermined phase angle from the initial position. After the feedback control, the operating mode is switched to a feedforward control, so as to return the angular phase of the camshaft from the predetermined position to the initial position by changing a controlled quantity or a control-signal duty cycle value for the electromagnetic brake with a predetermined time rate of change.

Abstract: A device for independent hydraulic actuation of phase and axial positions of a camshaft of an internal combustion engine with a phase adjuster and an actuating piston arranged on a common axis for axial displacement of the camshaft. In order to reduce the space needed and construction expenditure of the device, the phase adjuster also acts as the actuating piston for the camshaft.

Abstract: In a VVA apparatus, when an actual lift amount detected by a lift-amount detecting sensor exceeds a basic lift-amount target value by a predetermined value or more, ECU corrects a lift phase through a lift-phase varying mechanism to separate from a piston TDC with respect to a basic lift-phase target value.

Abstract: A valve control mechanism is disclosed which permits either or both of (a) axial displacement of the camshaft of an internal combustion engine, and (b) phasing of the camshaft (and hence of the valve operation)—i.e. an advance/retard function. The mechanism preferably includes a piston housed within a cylinder, this arrangement itself being mounted within a front end camshaft pulley. The piston is under hydraulic control, preferably governed by a microprocessor. A mechanical coupling between the piston and the camshaft translates the axial movement of the piston into one or both of axial displacement of the camshaft and relative advancement/retardation of its rotation.

Abstract: A camshaft system for use with an internal combustion engine including a camshaft having a plurality of lobes to actuate valves in the internal combustion engine, a sprocket coupled to the camshaft to drive the camshaft, and a target wheel coupled to the camshaft, the target wheel having an irregular surface capable of providing process data for operation of a plurality of internal combustion engine configurations.

Abstract: A turbo-fed internal combustion engine has a first and a second exhaust-gas valve per cylinder, these exhaust-gas valves each being connected to their respective exhaust manifold. One exhaust manifold conducts exhaust gases to an exhaust-gas turbine and the other exhaust manifold conducts subsequent exhaust gases past this exhaust-gas turbine which drives a compressor for charge air. The intake valve of the cylinder is arranged so as, as the engine speed increases, to close either earlier, before the piston reaches its bottom dead center, or later, after the piston has passed its bottom dead center. In this way, the temperature increase resulting from compression in the cylinder is reduced. Cooled air from the compressor can be taken in so as to obtain an adequate degree of filling in the cylinder, with a lower final temperature.

Abstract: The movable valve apparatus (1) includes the movable valve mechanism (10), the hydraulic pressure control valve (12), and the controller (14). The movable valve mechaiism (10) changes ite opening/closing timing of an air intake or exhaust valve depending on the supplied hydraulic pressure of the working fluid. The hydraulic pressure cotitiol valve (12) adjusts the supplied hydraulic pressure depending on the working condition of the spool (40). The controller (14) controls the solenoid (44) that drives the spool (40). When it is determined that the spool (40) is in the returning state, in which the spool (40) starts moving toward the initial position, the foreign object removal operation is executed. During the toreign removal operation, the spool (40) temporarily reciprocates in order to remove foreign objects in the hydraulic pressure control valve (12).

Abstract: A valve train for an internal combustion engine has a variable valve performance mechanism for changing the valve open angle of at least one set of intake valves and exhaust valves. The valve train further includes an electronic control unit (ECU) for controlling the variable valve performance mechanism and a sensor for detecting the running state of the engine. The ECU judges whether there is a malfunction in the engine based on detection signals from the sensor. If there is a malfunction in the engine, the ECU actuates the variable valve performance mechanism to decrease the valve overlap thereby performing a failsafe. The ECU also advances the closing timing of the intake valves. Alternatively, the ECU retards the opening timing of the exhaust valves.

Abstract: In a valve timing control apparatus for an internal combustion engine using an oil pressure control, a feedback correction amount is calculated so as to have a linear term proportional to a deviation between a target value and an actual value of the valve timing control apparatus, and a non-linear term using a switching function by a sliding mode control. Further, a dither control is added to the feedback correction amount and a learning is performed for a basic control amount and a control gain. Therefore, a control can be executed with high robust, high accuracy and quick response.

Abstract: A hydraulic control system for an internal combustion engine is provided which comprises a first hydraulic operating mechanism and a second hydraulic operating mechanism, the first hydraulic operating mechanism and the second hydraulic operating mechanism being operated independently by oil pressure of a common oil press source, and a circulation line that supplies pressure oil discharged from the first hydraulic operating mechanism to the second hydraulic operating mechanism.

Abstract: An internal combustion engine includes a cam which actuates a valve by torque of a camshaft and is movable in the radial direction of the camshaft and includes a lift portion which moves forward and backward in the direction of the valve, a support mechanism which rotates the cam with the camshaft, and a device which engages the cam with the camshaft and releases the cam from the camshaft in accordance with engine operating conditions.

Abstract: A valve moving apparatus of an internal combustion engine has an intake camshaft with an intake variable cam piece for opening and closing an intake valve, and an exhaust camshaft with an exhaust variable cam piece for opening and closing an exhaust valve. Each variable cam piece has a low speed cam section and a high speed cam section and is movable axially relatively to the camshaft. A hydraulic driving mechanism is provided for moving the variable cam piece axially in accordance with engine operation condition. The driving mechanism has a driving piston and arms touching both sides of the variable cam piece. When valve operating characteristic of the intake valve or the exhaust valve is changed corresponding to engine operation condition, response is improved. The engine can be miniaturized.

Abstract: A variable valve operating system of an internal combustion engine comprises a first variable mechanism 1 capable of variably controlling a lift characteristic of an intake valve 12, and a second variable mechanism 2 capable of variably controlling a valve-open and/or valve-close timing characteristic of the intake valve. The first variable mechanism varies an oscillating position of an oscillating cam 17 via a transmission mechanism 18 by controlling a rotational position of a control shaft 32 by an electric motor 34. On the other hand, the second variable mechanism is constructed to change a phase by axially moving a ring gear 43 by way of hydraulic-pressure supply or release to and from first and second hydraulic pressure chambers 49 and 50 so as to produce relative rotation between a timing sprocket 40 and a drive shaft 13. At the initial state of engine starting, the system operates to drive only the first variable mechanism.

Abstract: A variable valve apparatus of an internal combustion engine is capable of realizing more precise valve characteristic control by reducing the error in-detection of the amount of movement of a camshaft caused by a difference in the rate of thermal expansion. The variable valve apparatus has a camshaft that is supported so as to be rotatable and slidable in a direction of an axis thereof and that has three-dimensional cams whose cam profile continuously changes in the direction of the axis. The apparatus also has an actuator for moving the camshaft in the direction of its axis. The apparatus further has a camshaft position sensor provided in a cylinder head, a detected portion provided in the camshaft, and a camshaft movement amount detection portion for detecting the amount of movement of the camshaft in the direction of the axis. The camshaft movement amount detection portion is provided near a camshaft reference position.

Abstract: A valve operating system of an internal combustion engine enabling both valve working angle and phase to be varied, includes a variable working angle control mechanism being responsive to a supply pressure of working fluid to adjust a working angle of an intake valve, and a variable phase control mechanism being responsive to a supply pressure of working fluid to adjust a phase of the working angle of the intake valve. A control unit controls the supply pressure to each of the control mechanisms depending on engine operating conditions. In a cold-engine state that the temperature of working fluid is below a predetermined temperature, an intake valve open timing is retarded in comparison with a predetermined stability-limit valve open timing, by limiting a controlled variable of at least one of the control mechanisms.

Abstract: Either of intake and exhaust valves of an internal combustion engine is provided with a variable valve timing device. In a low-speed, low-load range, exhaust valve advanced-closing control is performed to close the exhaust valve at an earlier timing than the top dead center on the intake stroke, thereby trapping residual combustion gases in the cylinder. Furthermore, the cylinder temperature is raised by setting the intake valve opening timing at around the top dead center on the intake stroke or at a later timing thereof to thereby compress by the piston the residual gases in the cylinder during a period from closing the exhaust valve till the top dead center on the intake stroke. Thus it becomes possible to take in the air-fuel mixture into the cylinder at a higher cylinder temperature than the gas temperature of internal EGR caused by conventional valve overlap.

Abstract: A camshaft provided with three-dimensional cams is connected at its one end to a valve lift-varying actuator. By the valve lift-varying actuator or displacing the camshaft in the directions of an axis of the camshaft, the lift characteristic of intake valves set by the three-dimensional cams is variably controlled to a target amount of valve lift. The valve lift characteristic related to this control is detected as a detected amount of valve lift by a reference-purposed detected portion and a cam angle sensor. An apparatus and a method diagnoses abnormalities in the valve lift-varying actuator by, for example, evaluating whether the amount of change in the detected amount of valve lift is at most a predetermined value and the absolute value of a difference between the detected amount of valve lift and the target amount of valve lift is greater than a predetermined value.

Abstract: The invention relates to a control method for the electrical actuator of a variable valve train, the actuator being embodied in the form of a worm gear pair, in which a sensor detects a position value (measured position value) of an eccentric shaft, a control difference is generated in a feedback branch with the use of the measured position value, and the electrical actuator is actuated. To suppress interferences in the control system, an observer value is formed that is associated with the position value from the pulse duty factor of the pulse-width modulation. The observer value is composed to a comparison value formed from the measured position value. The detected measured position value is not accepted if the deviation of the observer value from the comparison value exceeds a defined limit.

Abstract: A reference position of a camshaft used in detection of a rotational phase of the camshaft relative to an engine crankshaft during the feedback control operation of a variable valve-timing controlling system adjustably changing the valve-timing of the engine, is learned in such a manner that result of detection of the rotational phase is smoothed more effectively than when the feedback control operation of the variable valve-timing controlling system is carried out, so as absorb unequal spaces among detection subjects of the cam sensor arranged around the camshaft.

Abstract: The invention relates to an electrically driven device (1) for the angular adjustment of a shaft relative to its drive (2), said device comprising an eccentric gearing that comprises at least one internally geared wheel and one spur gear that meshes with the internally geared wheel and can be driven by an electrically rotatable eccentric shaft. The considerable structural complexity and space requirement as also the noise level of prior art devices is reduced by the fact that the internally geared wheel is configured as a first and a second internally geared wheel (6, 9), and the spur gear is configured as a first and a second spur gear (16, 17) that have the same number of teeth and are rotatable in opposite directions, the internally geared wheels (6, 9) are connected to the drive (2) and the spur gears (16, 17) are connected to the camshaft and can be driven through a double eccentric shaft (20) comprising identical eccentrics (18, 19) arranged offset at 180° to each other.

Abstract: A process and a device for controlling selective cylinder filling in combustion engines with a variable valve drive, where the valve stroke and/or the valve opening and closing times of the cylinder intake valves are controllable. In order to ensure satisfactory idling quality also in direct fuel-injection engines in spite of the occurring production tolerances, at least one input magnitude is determined on whose basis conclusions can be drawn as to the filling level or filling level differences of each cylinder. From this input magnitude, a control signal for the variable valve operation is determined such that differing filling levels of the cylinder can be balanced out by adjusting the valve drive.

Abstract: A valve train for an internal combustion engine has a variable valve performance mechanism for changing the valve open angle of at least one set of intake valves and exhaust valves. The valve train further includes an electronic control unit (ECU) for controlling the variable valve performance mechanism and a sensor for detecting the running state of the engine. The ECU judges whether there is a malfunction in the engine based on detection signals from the sensor. if there is a malfunction in the engine, the ECU actuates the variable valve performance mechanism to decrease the valve overlap thereby performing a failsafe. The ECU also advances the closing timing of the intake valves. Alternatively, the ECU retards the opening timing of the exhaust valves.

Abstract: Internal combustion engine having a device for the valve timing, the valve timing periods and the valve lifts being continuously changeable and being definable as a function of the operating parameters of the internal combustion engine, characterized in that the switching thresholds for changing the valve timing periods and the valve lifts, which are obtained from a characteristic diagram extending over the rotational speed and the load, are weighted as a function of the gear and/or of the temperature.

Abstract: A device for adjusting the phase angle of a camshaft of an internal combustion engine includes a drive gear for driving a camshaft accommodated in a coaxial arrangement relative to the camshaft and an electric motor communicating with the camshaft via a Harmonic Drive having a roller bearing with an elliptical inner ring, an externally toothed, flexible gear arranged on the roller bearing, and a rigid, internally toothed gear engaging the externally toothed gear. A simple structure is achieved by providing the electric motor with a housing which is rigidly connected to the camshaft via retaining elements which extend through recesses in the drive gear so that the recesses restrict the allowable adjusting range of the camshaft.

Abstract: A valve train for an internal combustion engine has a variable valve performance mechanism for changing the valve open angle of at least one set of intake valves and exhaust valves. The valve train further includes an electronic control unit (ECU) for controlling the variable valve performance mechanism and a sensor for detecting the running state of the engine. The ECU judges whether there is a malfunction in the engine based on detection signals from the sensor. If there is a malfunction in the engine, the ECU actuates the variable valve performance mechanism to decrease the valve overlap thereby performing a failsafe. The ECU also advances the closing timing of the intake valves. Alternatively, the ECU retards the opening timing of the exhaust valve.

Abstract: A phase variation actuator has an outer rotor that is connected to a cam sprocket so that the outer rotor is rotatable together with the cam sprocket, and an inner rotor that is connected to a journal so that the inner rotor is rotatable together with the journal. The journal is rotatably supported by an internal combustion engine. A camshaft is inserted into a slide hole of the journal provided near the phase variation actuator so that the camshaft is slidable in the direction of the rotating axis of the camshaft. The camshaft is connected to the journal by meshing of splines so that the camshaft is rotatable together with the journal.

Abstract: A variable valve drive mechanism of an internal combustion engine is provided which includes a camshaft that is operatively connected to a crankshaft of the engine such that the camshaft is rotated by the crankshaft, a rotating cam provided on the camshaft, and an intermediate drive mechanism disposed between the camshaft and an intake or exhaust valve of the engine. The intermediate drive mechanism is supported rockably on a shaft that is different from the camshaft, and includes an input portion operable to be driven by the rotating cam of the camshaft, and an output portion operable to drive the valve when the input portion is driven by the rotating cam. The variable valve drive mechanism further includes an intermediate phase-difference varying device for varying a relative phase difference between the input portion and the output portion of the intermediate drive mechanism.

Abstract: A two-step roller finger follower includes an elongate body having a first side member and a second side member. A first end and a second end interconnect the first and second side members. The first and second side member define first and second pin orifices, respectively. A center roller is disposed between the first and second side members. The center roller defines a shaft orifice therethrough. A shaft extends through the shaft orifice. A first shaft end is disposed proximate the first side member, and the second shaft end is disposed proximate the second side member. The second shaft end defines a shaft bore therein. The first shaft end defines a pin chamber therein. The shaft bore being is substantially concentric with and intersects the pin chamber. A locking pin assembly is disposed partially within the shaft bore, the pin chamber and at least one of the pin orifices.

Abstract: A camshaft provided with three-dimensional cams is connected at its one end to a valve lift-varying actuator. By the valve lift-varying actuator displacing the camshaft in the directions of an axis of the camshaft, the lift characteristic of intake valves set by the three-dimensional cams is variably controlled to a target amount of valve lift. The valve lift characteristic related to this control is detected as a detected amount of valve lift by a reference-purposed detected portion and a cam angle sensor. An apparatus and a method diagnoses abnormalities in the valve lift-varying actuator by, for example, evaluating whether the amount of change in the detected amount of valve lift is at most a predetermined value and the absolute value of a difference between the detected amount of valve lift and the target amount of valve lift is greater than a predetermined value.

Abstract: An apparatus controls valve timing of an internal combustion engine that is provided with helical splines of an actuator for varying a phase difference in rotation and an actuator for varying a cam profile and lift of an intake cam. When the apparatus for controlling valve timing and respective actuators are not driven, a valve timing can be automatically established, which can achieve a cold valve overlap &thgr;ov. Carburetion of fuel can be promoted in the combustion chamber and intake ports by the blow-back of exhaust resulting from the cold valve overlap &thgr;ov. A mixture is made into a sufficient air-fuel ratio without depending on an increase in fuel when cold idling, wherein combustion is stabilized still more than in a case where valve overlap is not increased, cold hesitation can be prevented from occurring, and drivability can be maintained in a comparatively favorable state.

Abstract: A variable valve timing apparatus is employed in an engine that includes a crankshaft, an intake camshaft for driving intake valves, an exhaust camshaft for driving exhaust valves, and a transmission for transmitting rotation between the crankshaft, the intake camshaft, and the exhaust camshaft. The variable valve timing apparatus varies the valve timing of the intake valves or the exhaust valves. A first actuator is incorporated in the transmission to adjust the rotational phase of the intake camshaft or the exhaust camshaft relative to the crankshaft. A second actuator is arranged on the intake camshaft or the exhaust camshaft to adjust the valve lift of the associated valves. The result is a compact engine that avoids interference with other parts in the engine compartment.

Abstract: A new and improved two-part phase changing device which has an axially movable quill shaft extending through a hollow camshaft and has one end of the quill shaft directly connected to the hub member of the timing gear through straight splines and has the other end of the quill shaft connected by helical splines to the camshaft so that axial movement of the quill shaft provided by a ball nut transmission located adjacent the helical splines of the quill shaft serves to angularly reposition the camshaft a predetermined distance upon actuation of an electric stepper motor.

Abstract: In a variable valve control device, the minimum operating hydraulic pressure necessary for controlling the vane rotor is arranged to be higher than that for axially moving the piston member. Thus, whenever the angular phase is actually changed, the hydraulic pressure sufficient enough to move the piston member may be always ready to be applied to the axial movement control member. Therefore, when the intake camshaft is at the lowest lift stroke position, the intake camshaft may be easily shifted from the lowest lift stroke position to the higher lift stroke position without time delay so that a highly accurate angular phase control of the intake camshaft relative to the timing pulley may be secured.