Abstract: In an internal combustion engine a valve actuation control arrangement is provided, which has at least three independently axially displaceable cam elements and a switch gate which has at least one continuous gate track for displacing the at least three cam elements sequentially one after the other.

Abstract: A valve drive of an internal combustion engine is provided, having a camshaft (1) which includes a carrier shaft (2) and a cam part (3), which is arranged thereon in a rotationally fixed manner and displaceable between two axial positions and which has at least one cam group of directly adjoining cams (5, 6) having different cam elevations and an axial gate (8) having two cam tracks (9, 10) that extend axially along the circumference in opposing directions, and further having an actuating element (11) that can be coupled to the axial gate for displacing the cam part in the direction of both cam tracks. The cam tracks are arranged one behind the other in the circumferential direction of the axial gate (8).

Abstract: A drive control device which estimates an engine torque during traveling in a fixed gear ratio mode is disclosed. The drive control device includes the engagement mechanism including the revolution component revolved by the torque of the engine and the fixed component that engages with the revolution component, the torque applying unit which applies torque to the revolution component and the first transmitting control unit which engages the engagement mechanism to make the engagement mechanism receive the reaction force of the torque. The torque estimating control unit executes control of torque applied to the revolution component by the torque applying unit during executing the control by the first transmitting control unit to detect the phase change between the revolution component and the fixed component and estimates the torque of the engine based on the phase change and torque applied by the torque applying unit.

Abstract: A valve drive for an internal combustion engine, wherein in order to activate gas exchange valves at least one camshaft having at least one sliding cam which can be displaced axially on the camshaft is provided, wherein the respective sliding cam has a sliding block section with a plurality of grooves which are formed on an outer lateral face and are positioned one behind the other on the circumference, wherein in order to bring about displacement of the respective sliding cam an actuator is provided with a first pin for displacement in the two directions about a first axial segment and a second pin for displacement in the two directions about a second axial segment. The sliding block section is manufactured in certain sections from a material with a relatively high electrical conductivity and in certain sections from a material with a relatively low electrical conductivity.

Abstract: In a valve drive train device, particularly of an internal combustion engine, having an actuating device provided to displace at least one first axially displaceable cam element using a shifting gate, the actuating device is designed for switching the axially displaceable first cam element into the various switching positions.

Abstract: A variable valve lift apparatus may include a control shaft slidably disposed within a camshaft, a cam which is slidably disposed to the camshaft and a high lift cam lobe and a low lift cam lobe is formed thereto, a valve opening/closing unit contacting the cam and a control portion which moves the cam for the high lift cam lobe or the low lift cam lobe selectively to contact the valve opening/closing unit according to operation of the control shaft.

Abstract: There is provided a control apparatus for an internal combustion engine, which can favorably reduce a load necessary for cranking at the time of the next start, while preventing the fresh air inflow to a catalyst at the time of the stop of the internal combustion engine. A valve stop command is issued to an electrically-driven actuator so that the operational states of intake and exhaust valves becomes a valve closed/stopped state when fuel supply is stopped in response to an establishment of a predetermined stop condition of the internal combustion engine. Then, to return the operational states of the intake and exhaust valves to a valve operating state after the completion of the stopping operation of the internal combustion engine, a valve return command is issued to the actuator, and a crankshaft is rotationally driven by a predetermined angle required to return the operational states of the intake and exhaust valves to the valve operating state.

Abstract: An adjustable camshaft having at least one shaft, and having at least one cam package which has at least two different cams and/or cam contours. According to the invention, the cams and/or the cam contours of the cam packages have different widths.

Abstract: In a valve drive train arrangement for an internal combustion engine having a camshaft with a cam element axially displaceable supported on the camshaft and having a stop for limiting the axial movement of the cam element, the stop has at least one stop element extending radially from the camshaft for engagement with the cam element.

Abstract: An internal combustion engine having a cylinder head and a cylinder head cover, wherein in order to activate charge cycle valves, at least one rotatably mounted cam shaft is provided with at least one sliding cam which can be slid axially on the respective cam shaft, wherein the respective sliding cam has at least one slotted link section with at least one groove, wherein in order to bring about axial sliding of the respective sliding cam, an actuator is provided, and wherein after axial sliding on the respective cam shaft, the respective sliding cam can be latched in its axial relative position relative to a charge cycle valve to be activated by a locking device which has a first latching element with a plurality of latching depressions and at least one second latching element which interacts with the first latching element.

Abstract: A valve drive assembly cooperable with gas exchange valves of an internal combustion engine having a cam shaft and at least one came support rotatably fixed and axially displaceable on the cam shaft and having at least two cam profiles selectively engageable with a roller provided on a follower engageable with a valve comprising a cam support having a cylindrical surface disposed coaxially with a cam shaft, provided with a pair of oppositely inclined, spiral grooves; and means selectively insertable into the grooves, coacting with side walls of such grooves as the cam shaft rotates to effect axial displacement of the cam support.

Abstract: A valve drive device for switching the stroke of gas exchange valves of an internal combustion engine includes a camshaft configured, at least in part, as a hollow shaft. A cam unit includes at least two different cams disposed on the camshaft so as to be rotationally engaged and axially displaceable with respect thereto. An adjustment sleeve is disposed so as to be rotationally engaged on an adjustment shaft and rotatable and axially displaceable inside the camshaft. The adjustment sleeve includes thereon a closed adjustment contour extending about a circumference of the adjustment sleeve and is operatively connected to the cam unit through an adjustment clearance in the camshaft via a first coupling element configured to permanently engage in the adjustment contour. A further coupling element is configured to permanently engage in the adjustment contour and connect to the camshaft so as to be fixed in position.

Abstract: A plurality of reference signals output from a controller which computes an operation amount of an electric actuator is subjected to the logical operation, and the power supply to a drive circuit for the electric actuator is shut off based on an output by the logical operation.

Abstract: In a valve drive device, especially for an internal combustion engine including a camshaft with a cam element which is axially movably supported on the camshaft but in a rotationally fixed manner, the cam element includes a gate structure and an actuation device is provided with at least one shift element for engagement with the gate arrangement for axially displacing the cam element and the shift element has a rotationally asymmetrical basic shape in order to follow the gate structure when placed in engagement therewith.

Abstract: An internal combustion piston engine having gas exchange valves actuated by cams of a camshaft. The cams are sliding cams having two cams per sliding cam unit situated on a basic shaft in rotationally fixed fashion but axially displaceable. At least one actuator unit has two actuator pins for displacing the sliding cam units into different axial positions using displacement grooves on the circumference of the sliding cam units, the grooves being helical and situated mirror-symmetrically, and having an ejection ramp for the actuator pins. The actuator pins are spring-loaded toward the sliding cam unit and, in retracted positions, can be fixed by arresting devices, which have control needles that correspond to clamping bodies of locking devices. These needles are actuatable by an electromagnet unit, with the control needles being connected with a needle bridge. A pin engages the needle bridge, and the pin is controlled by the electromagnet unit.

Abstract: A method of conserving fuel in the operation of multi-cylinder internal combustion engines. The present method described here allows a portion of the cylinders of an internal combustion engine to be de-activated when less power is required, thus allowing the engine to provide full power when required, or less power with substantial fuel savings. The present method does so by altering the normal operation of intake and exhaust valves by leaving the intake valve at least partially closed, and the exhaust valve at least partially open. The present method overcomes numerous problems in the prior art, such as excess load placed on the engine caused by trapped gases, damaging thermal gradients across the engine block, and difficulty of retrofitting existing engines.

Abstract: In an internal combustion engine valve drive train shifting device including a camshaft having at least two shifting units arranged on the camshaft in spaced relationship, at least one coupling unit is provided interconnecting the at least two shifting units for shifting purposes.

Abstract: A valve drive assembly for selectively actuating a pair of valves of an internal combustion engine generally consisting of a pairs of cam supports rotatably fixed an axially displaceable on a camshaft, each provided with at least two cam profiles; means rotatably fixed and axially displaceable relative to the cam shaft, interposed between the cam supports; and means for selectively axially displacing the cam supports and the interposed means as a unit.

Abstract: In a valve drive arrangement for an internal combustion engine including a camshaft carrying axially movable cam elements provided with cams for operating gas exchange valves of the internal combustion engine and an actuation device having at least one shift element which is provided to shift cam element by means of a shifting gate between opposite axial positions, the valve drive arrangement has a change-over device for changing the axial shift direction of the shift element from one to the opposite axial position.

Abstract: A valve drive for an internal combustion engine, wherein in order to activate gas exchange valves at least one camshaft having at least one sliding cam which can be displaced axially on the camshaft is provided, wherein the respective sliding cam has a sliding block section with a plurality of grooves which are formed on an outer lateral face and are positioned one behind the other on the circumference, wherein in order to bring about displacement of the respective sliding cam an actuator is provided with a first pin for displacement in the two directions about a first axial segment and a second pin for displacement in the two directions about a second axial segment. The sliding block section is manufactured in certain sections from a material with a relatively high electrical conductivity and in certain sections from a material with a relatively low electrical conductivity.

Abstract: A valve drive for activation of gas exchange valves of internal combustion engines, with which valve stroke switching is accomplished with little effort, a low construction height, and at low switching forces. Incorrect switching and damage to the camshaft during valve stroke switching are avoided, even at high engine speeds of rotation. An adjustment shaft that is rotatable by the camshaft and parallel to the camshaft has two adjustment devices rotatably disposed on it, along with two tappets between the adjustment devices. The tappets are connected with a shift gate for valve switching between two different cam profiles of a cam package that is axially displaceable on the camshaft. The tappets each have a contour that contacts the adjustment devices via a guide pin. A gear wheel engages with a gear segment on the camshaft, via a drive on the adjustment shaft, to rotate the adjustment shaft.

Abstract: A valve drive of an internal combustion engine with a camshaft including cams for actuating gas-exchange valves, wherein at least one cam, comprising several cam faces, is guided nonrotatably but with freedom of axial movement on the camshaft, wherein a stroke profile, which cooperates with an actuating pin for the axial displacement of the cam, is assigned to the associated axially displaceable cam, and wherein the stroke profile of the axially displaceable cam in question comprises several stroke curves. A first stroke curve and a second stroke curve of the stroke profile are contoured both in the axial direction and in the radial direction such that the contour in the axial direction of the stroke profile of the camshaft is responsible for a defined axial displacement of the associated cam, and the contour in the radial direction of the stroke profile of the camshaft prevents the stroke curves from colliding.

Abstract: A variable valve train for actuating a plurality of gas exchange valves of an internal combustion engine includes a plurality of individual cam sleeves axially displaceable relative to one another and disposed so as to form the camshaft. Each of the plurality of individual cam sleeves include a plurality of different cam profiles. A switching shaft is disposed inside the plurality of cam sleeves and is configured to rotate together with the plurality of cam sleeves. A switching ball operatively connects one of the plurality of cam sleeves to a switching contour disposed on the switching shaft. A displacement piece is disposed so as to be rotationally engaged but axially displaceable on one of the plurality of cam sleeves and connected to the switching shaft. An actuator is operatively connectable to the displacement piece by the switching ball so as to displace the one of the plurality of cam sleeves.

Abstract: In a valve drive arrangement of an internal combustion engine, having a first camshaft unit which comprises an outer shaft and primary cams connected to the outer shaft, a second camshaft unit which comprises an inner shaft disposed in the outer shaft, secondary cams connected to the inner shaft and disposed on the outer shaft and an adjusting unit for adjusting the two camshaft units relative to each other an adjusting unit provides for an at least two stage sequential valve stroke wherein, in a switching process, two shaft elements of a camshaft unit are displaced sequentially one after the other.

Abstract: Provided is a variable valve operating apparatus for an internal combustion engine, which can switch, based on an actuation of a single actuator, operating characteristics of valves for a plurality of cylinders collectively and smoothly using a rigid member, while suppressing an increase in wear of a guide rail and reducing the number of delay mechanisms. A changeover mechanism to switch operating characteristics of valves for each cylinder of first and second cylinder groups is provided. The changeover mechanism includes link shafts as a rigid member which is displaced when being engaged with a helical guide rail as a result of the actuation of an electromagnetic solenoid. The changeover mechanism includes a delay mechanism, which delays the displacement of the second link shaft in a cylinder in which the valves are lifting when the electromagnetic solenoid is actuated, at some point in the link shafts between the first cylinder group and the second cylinder group.

Abstract: The invention relates to a device for camshaft adjustment in an internal combustion engine, having a lifting profile element which is provided in a rotationally fixed manner on an axially movable mounted camshaft and which provides a control groove, and having a control unit for generating a predetermined axial movement of the camshaft, wherein the control unit has a tappet unit which is preferably movable radially with respect to the camshaft and which is designed to controllably engage into the lifting profile element, wherein the lifting profile element forms a first control groove which is designed to interact with the tappet unit at a first penetration depth in order to describe a first axial movement of the camshaft, and the lifting profile element forms a second control groove which is designed to interact with the tappet unit at a second penetration depth, which differs from the first penetration depth, in order to describe a second axial movement, which differs from the first axial movement, of the c

Abstract: A valve train for an internal combustion engine for actuating gas exchange valves includes a camshaft in the form of a camshaft tube driven by a crankshaft of the internal combustion engine. A selector shaft is disposed in the camshaft tube. A surface of the selector shaft includes a shifting contour having an axial gradient. At least one cam carrier is disposed on the crankshaft and axially displaceable but rotationally fixed with respect to the camshaft. Each cam carrier includes an identical base-circle portion and a plurality of cam profiles. A rotationally fixed but axially displaceable shifting sleeve is disposed between the camshaft tube and the rotatable selector shaft of each cam carrier. Each shifting sleeve includes a hole. A shilling ball is disposed in the hole of each shifting sleeve. The shifting ball ois coupled with the shifting contour of the selector shaft so as to be guided by the selector shaft so as to axially displace the shifting sleeve by rotation of the selector shaft.

Abstract: An electromagnetic camshaft adjusting device has an armature unit, which can be moved relative to a yoke and core unit by energizing a stationary coil unit and which is designed to carry out an axial actuating movement and to exert a correspondingly axially directed actuating force on a rotating internal combustion engine camshaft by a slider unit interacting with the armature unit. The yoke and core unit is mounted such that it can rotate relative to the coil unit and provides a receptacle for the armature unit that is guided such that it can move axially in the yoke and core unit and has the slider unit firmly seated thereon.

Abstract: Disclosed herein is an internal combustion engine having a plurality of cylinders, a crankcase, a cylinder head and a cylinder-head cover, the cylinder head being formed from a cylinder-head lower part and a camshaft housing which is positioned between the cylinder-head cover and the cylinder-head lower part, and at least one camshaft and one sliding cam which can be displaced axially on the camshaft and has a slotted-guide section being provided for actuating gas exchange valves of the internal combustion engine, an actuator with an actuable pin being provided for bringing about an axial displacement of the sliding cam. The camshaft and the sliding cam are positioned in the camshaft housing. The camshaft, which is mounted rotatably for valve actuation, is arranged with the axially displaceable sliding cam in the camshaft housing in such a way that they can be attached to the cylinder-head lower part as one preassembled unit.

Abstract: A valve drive of an internal combustion engine with variable-lift gas exchange valve actuation. The valve drive has a camshaft with a support shaft and a cam piece arranged on the support shaft for conjoint rotation therewith and to be movable between axial positions. The cam piece has two cam groups of directly adjacent cams with different elevations and, on the end side, the cam piece has an axial slotted guide into which can be coupled an actuating element. The cam piece has a bearing journal which runs between the cam groups and rotatably mounted in a camshaft bearing point arranged in a positionally fixed manner in the engine. Here, the diameter of the bearing journal is larger than the envelope circle diameter of a cam closest to the bearing journal with the cam and camshaft bearing point overlapping axially in an axial position of the cam piece.

Abstract: A variable valve lift apparatus may include a control shaft slidably disposed within a camshaft, a cam which is slidably disposed to the camshaft and a high lift cam lobe and a low lift cam lobe is formed thereto, a valve opening/closing unit contacting the cam and a control portion which moves the cam for the high lift cam lobe or the low lift cam lobe selectively to contact the valve opening/closing unit according to operation of the control shaft.

Abstract: A valve drive for controlling gas exchange valves of an internal combustion engine. The valve drive has at least one valve camshaft that is supported within a cylinder head of the engine and that can be moved in rotation by a drive disk and an adjustment device, which has an adjustment motor and a gear train. The adjustment device provides for an axial movement and/or rotation of the valve camshaft relative to the drive disk in a specific manner upon actuation of the adjustment motor and by the intermediately connected gear train in order to vary in a specific manner an actuation of the gas exchange valves that occurs by cams of the valve camshaft. Also, the adjustment motor is placed predominantly or completely within a common chamber with the drive disk.

Abstract: A valve drive of an internal combustion engine is provided, having a camshaft (1) which includes a carrier shaft (2) and a cam part (3), which is arranged thereon in a rotationally fixed manner and displaceable between two axial positions and which has at least one cam group of directly adjoining cams (5, 6) having different cam elevations and an axial gate (8) having two cam tracks (9, 10) that extend axially along the circumference in opposing directions, and further having an actuating element (11) that can be coupled to the axial gate for displacing the cam part in the direction of both cam tracks. The cam tracks are arranged one behind the other in the circumferential direction of the axial gate (8).

Abstract: A valve train for an internal combustion engine includes a camshaft with a cam unit for actuating a gas exchange valve. The cam unit has at least two cam paths arranged axially one behind the other and is arranged on the camshaft in a rotation-resistant and axially displaceable manner, and has an actuating profile interacting with a displaceable actuating element between a home position and an actuating position radially to the axis of the camshaft for axially displacing the cam unit on the camshaft. The actuating profile is formed by the lateral front face of the cam unit, and the actuating element has at least one displaceable actuating pin that interacts with a lateral front face of the cam unit such that an axial displacement of the cam unit takes place and in each axial position a different cam path is activated to actuate the gas exchange valve.

Abstract: In a valve drive train device of an internal combustion engine, comprising a phase adjustment device for the adjustment of a phase position between a primary cam and a secondary cam which belong to a same category and which are arranged coaxial with one another, at least one is assigned to a pair of cams for executing a valve lift changeover so as to allow the valve drive train device to be instantly adjusted to a momentary operating situation.

Abstract: The invention relates to a splined-shaft connection between a hollow shaft or hub provided with an internal toothing system and a shaft provided with an external toothing system.

Abstract: In a valve train device, particularly of an internal combustion engine, which device has an actuating device for displacing at least one axially displaceable cam element and a gear shifting gate for axially displacing the cam element and furthermore at least one switch unit with a switch element and an actuator for operating the switch element so as to engage the gear shifting gate at least in one switching position and to move the switch element into a desired switching position, the gear shifting gate has at least one intermediate segment for terminating a switching action.

Abstract: In a valve drive arrangement for an internal combustion engine including a camshaft carrying axially movable cam elements provided with cams for operating gas exchange valves of the internal combustion engine and an actuation device having at least one shift element which is provided to shift cam element by means of a shifting gate between opposite axial positions, the valve drive arrangement has a change-over device for changing the axial shift direction of the shift element from one to the opposite axial position.

Abstract: A valve drive (1, 1?) of an internal combustion engine with stroke-variable gas-exchange valve activation is provided. The valve drive includes a camshaft (2, 2?) with a carrier shaft (3) and a cam piece (4, 4?) that is arranged in a rotationally locked way on the carrier shaft and that can move between axial positions and that has a cam group of directly adjacent cams (14a-c, 15a-c) with different lobes and a groove-shaped axial link (16, 16?) and an activation element (18, 19) that can be coupled in the axial link for shifting the cam piece on the carrier shaft. The cam piece is provided with a bearing journal (12, 13, or 12?) on which the camshaft is supported in the radial direction at a camshaft bearing point (9, 10, or 9?) of the internal combustion engine. Here, the axial link is constructed overlapping with the camshaft bearing point on the bearing journal in the axial direction, and the activation element runs in the camshaft bearing point.

Abstract: The invention relates to a transmission assembly (34), for imparting a phase difference between an outer wheel and an inner wheel of a spline VVT. The assembly comprises a tubular meshing member (36) having an inner surface (38) and an outer surface (40), wherein at least a portion of the inner surface is provided with a first spline (42) and at least a portion of the outer surface is provided with a second spline (44). The first spline and the second spline do not have the same pitch in the same groove direction. The transmission assembly further comprises a bearing arrangement (46) and an actuation member (48). The bearing arrangement is arranged between the meshing member and the actuation member to allow a transfer of an axial displacement of the actuation member to the meshing member and allow a rotation of the meshing member relative to the actuation member.

Abstract: When cranking is started, a control unit of an ECU determines an advance amount by which an intake valve closing timing is advanced from a fully retarded position toward a bottom dead center, and transmits the determined advance amount to a variable valve timing mechanism. After cranking is started, the control unit determines that there is an abnormality in the variable valve timing mechanism, when the advance amount is larger than 0, and when an actual intake valve closing timing, determined using an intake cam angle from a cam angle sensor and a crank angle from a crank angle sensor, is not advanced from the fully retarded position. When it is determined that there is an abnormality in the variable valve timing mechanism, the control unit outputs a control signal to an inverter to increase an output torque of a motor, which is a driving source for cranking.

Abstract: A multi-cam electric valve mechanism for engine is disclosed, which comprises: a motor fixed on a cylinder; a motor shaft wherein one side of it connected to the motor and rotated accordingly and the other side of it symmetrically provided with a plurality of rotors whose shafts are perpendicular to the motor shaft; a ring-shaped cam with a plurality of wave-shaped grooves on the circumference thereof corresponding to the rotors and for setting same; a rotation-stopping lever connected to the cylinder and cam respectively to let the cam linearly move along with it; and a valve lever wherein one side of it connected to the cam and the other side of it connected to a valve.

Abstract: There is provided an actuator device for a variable valve apparatus. The variable valve apparatus has a control shaft to vary operation characteristics of an engine valve by an axial movement thereof. The actuator device has a rotatable screw shaft, a movable member axially movable with rotation of the screw shaft and a transmission mechanism unit that converts an axial movement of the movable member to the axial movement of the control shaft. An amount of the axial movement of the movable member is larger than an amount of the axial movement of the control shaft.

Abstract: A drive valve for an internal combustion engine comprising a variable hub profile for a valve having a lever supported on a variable support point by means of a switchable support element which provides possibilities for influencing the hub profile and alternatively and cumulatively, the cam is axially displaced such that various cam paths are active on the lever.

Abstract: The invention relates to a valve drive for internal combustion engines, comprising at least one cam assembly which can be axially displaced on a camshaft. The assembly consists of at least two cams having different profiles and actuating optionally at least one gas exchange valve for adjusting different valve lifts and/or valve timing. The aim of the invention is to create a space-saving and simple valve drive for an internal combustion engine of the aforementioned type, which allows valve lift and/or valve timing to be adjusted without an additional actuation stage. For this purpose, one cam is connected to the camshaft so as to rotate with the camshaft and the other cam is mounted so as to be rotated on the camshaft. The cam that is rotationally mounted on the camshaft can be positively connected to and released from the cam that is connected so as to rotate with the camshaft via a controlled pilot and main locking plunger.

Abstract: A feed screw mechanism including a screwed shaft which moves linearly along with the control shaft, and a rotation spindle which rotates in a circumferential direction. The feed screw mechanism converts a rotational movement of the rotation spindle into a linear movement of the screwed shaft. A protrusion protrudes outwardly from the rotation spindle. An internal thread member engages with an outer wall surface of the rotation spindle. A motor stator generating a magnetic is positioned over the rotation spindle, and is sandwiched between the protrusion and the internal thread member in an axial direction of the rotation spindle.

Abstract: The invention relates to a valve drive of an internal combustion engine, comprising at least one camshaft whereon at least one cam carrier is arranged in a rotationally fixed and axially displaceable manner. Means for applying axial tension are formed between the at least one camshaft and the at least one cam support, thereby enabling the at least one cam support to be fixed in an axial manner.

Abstract: A valve train with cam switching used for intermittent control of a four-cycle internal combustion engine. The valve train comprises a splined shaft, one cam block per cylinder, and a housing-mounted actuator pin. On each end of the cam block is a cylindrical end piece and a mirror-symmetric displacing groove. A housing-mounting actuator pin inserts radially into each displacing groove. The cam block reciprocates axially through the cooperation of the actuator pins and the displacing grooves when the engine is running. Low wear of the valve train and a high switching speed are achieved due to the fact that the displacing grooves possess an accelerating flank with an impact ramp that results in a constant, low initial axial speed of the cam block and a feeble impact force of the actuator pins.

Abstract: A helical cam device for use with a wide variety of applications generally includes a first cam component, a second cam component and an axial guide. The cam components each have a helical cam track located on an axial end, so that coaxial alignment of the two cam components allows opposing cam tracks to contact and rotate against each other. The helical cam tracks, which are preferably divided into quadrant sections, are designed such that relative rotational movement between the cam components causes a corresponding relative axial movement. According to one embodiment, the axial guide is a cylindrical rod passing through the center of the cam components; in another embodiment, it is a cylindrical sleeve surrounding the cam components. Moreover, barrel slots, detents and/or truncated peaks can be used to control the travel of the cam components.

Abstract: A variable valve timing system includes a toothed rotating sleeve, a rack, and an actuator. The rack has a first end, a second end with a plurality of teeth in meshing contact with the teeth of rotating sleeves of the valve and being linearly moveable to rotate the sleeves. The actuator includes a housing, a control valve, and at least one check valve. The housing slidably receives a piston coupled to the rack separating a chamber in the housing into first and second chambers. The control valve selectively directs fluid from the first to the second chamber or vice versa. When the rack is shifted linearly by vibrational impulses from the engine, the piston moves linearly within the housing, pressurizing the first or the second chamber and under control of the control valve, fluid recirculates from the first or the second chamber to the other chamber.