Abstract: A variable valve actuation (VVA) apparatus for an internal combustion engine comprises a drive cam fixed to a drive shaft, a valve operating (VO) cam supported by the drive shaft for pivotal motion, and a motion transmitting mechanism interconnecting the drive cam and the VO cam. The VO cam having a cam surface that extends at least from a cam lift start point to a maximum cam lift point. The cam surface includes a first section providing a ramp section, a second section providing a positive acceleration section, and a third section providing a zero acceleration section that includes a situation where acceleration continuously vary within a predetermined infinitesimal window about zero.

Abstract: A variable valve actuation (VVA) apparatus comprises a supporting arm to support a pivot center of a rocker arm. The rocker arm operates a valve operating (VO) cam in response to operation of a drive cam on an engine driven drive shaft. The supporting arm is mounted for angular motion about an axis of rotation of the drive shaft to move the pivot center of the rocker arm along a circle about the drive shaft axis. The VO cam is mounted for pivot motion about the drive shaft axis. A supporting arm (SA) actuator is provided to position the pivot center of the rocker arm to any angular position to shift mode of operation of the VVA apparatus.

Abstract: A variable valve actuation (VVA) apparatus is disclosed. The VVA apparatus can keep an engine cylinder valve closed. Rotating a camshaft in timed relation with a crankshaft of the engine causes an eccentric crank cam to move a link or crank arm, thereby causing one end of a rocker arm to reciprocate. This causes the other end of the rocker arm to reciprocate. The reciprocating motion of the other end of the rocker arm is transmitted via a link to a valve operating (VO) cam, thereby causing the VO cam to pivot to push a valve lifter for opening the associated cylinder valve. An eccentric circular cam, fixed to a control rod, supports the rocker arm for rotation relative thereto in such a manner that rotation of the control rod causes a pivot center of the rocker arm to move, thereby changing position of the VO cam relative to the valve lifter. The change in the position of the VO cam causes its valve lift diagram to change.

Abstract: A variable valve timing and lift system comprises a camshaft having a rotary cam and a valve operating (VO) cam, and a control rod having an integral portion. The integral portion in the form of an eccentric cam supports a rocker arm. The rotary cam is fixed to the camshaft. The VO cam is in contact with a valve lifter for a cylinder valve of an engine. A torsion spring winds about the camshaft to apply a bias to the VO cam. The rocker arm has a first arm cooperating with the rotary cam and a second arm cooperating with a projecting radial lever of the VO cam. Under the action of the torsion spring, the lever of the VO cam is held in engagement with the second arm of the rocker arm and the second arm of the rocker arm is held in engagement with the rotary cam.

Abstract: A variable valve actuation (VVA) apparatus comprises an eccentric rotary (ER) cam fixed to a driving shaft for rotation therewith, a pivotal valve operating (VO) cam, a rocker arm having a first arm and a second arm, a control rod having an eccentric control cam, and a crank arm. The eccentric control cam supports the rocker arm for pivotal motion. The crank arm interconnects the ER cam and the first arm of the rocker arm. A link interconnects the second arm of the rocker arm and the VO cam.

Abstract: A device for moving a hollow cam relative to a driving shaft includes an intermediate member between a drive member fixed to the driving shaft and a driven member fixe to the hollow cam. A cam ring in the form of an eccentric cam is disposed between the driving shaft and the intermediate member to maintain eccentric rotation of the intermediate member relative to the driving shaft. A driver mechanism controls the angular position of the cam ring.

Abstract: An cylinder valve controlling apparatus comprises a first rocker arm and a second rocker arm cooperating with a middle lift cam and a low lift cam, respectively, to active two cylinder valves arranged for each of the engine cylinders, respectively. The apparatus further comprises a free rocker arm cooperating with a high lift cam. During engine operation at low speeds, the first rocker arm activates one of the cylinder valves in accordance with the profile of the middle lift cam, while the second rocker arm activates the other cylinder valve in accordance with the profile of the low lift cam. During engine operation at middle speeds, a coupling including a first lever establish drive connection between the first and second rocker arms and thus the first and second rocker arms follow the profile of the middle cam.

Abstract: A variable camshaft phase changing device comprises two axially-spaced annular gears disposed and engaged between a drive and a driven member, a plurality of coil springs compressed between the annular gears to bias one apart from the other, and an annular piston having a plurality of pins which pass through one and the other of the annular gears. The plurality of pins have heads arranged to come into driving relation with the other of the annular gears.

Abstract: According to a control strategy, a cylinder valve control device is monitored and operation of the engine is modified. The cylinder valve control device includes a driving shaft driven by the engine to drive an intermediate member which in turn drives a cam arranged to open an engine intake valve, and a driver which is operative in response to a command to vary an amount of eccentricity of the intermediate member with respect to a shaft axis of the driving shaft. During one mode of engine operation, the intermediate member is supported in a support for rotation about an axis in eccentric condition with respect to the shaft axis to accelerate and decelerate the cam with respect to rotation of the driving shaft. During another mode of engine operation, the intermediate member is in concentric condition with respect to the shaft axis to provide a synchronous motion of the cam with rotation of the driving shaft. In response to the eccentricity of the intermediate member, the engine operation is modified.

Abstract: A cylinder valve operating system comprises a pivotable rocker arm engaged with at least one cylinder valve, a first free cam follower supported by the rocker arm and driven by a first cam with a cam profile suitable for operation at low engine speeds, a second free cam follower supported by the rocker arm and driven by a second cam with a cam profile suitable for operation at high engine speeds, a first lever for establishing a positive motion connection between the first free cam follower and the rocker arm, a second lever for establishing a positive motion connection between the second free cam follower and the rocker arm, and a hydraulic driver for the first and second levers.

Abstract: A phase changing mechanism is disclosed which is applicable to a valve gear of a dual overhead camshaft internal combustion engine. The mechanism comprises a driving shaft, a cam rotatable relative to the driving shaft, a drive member fixed to the driving shaft, a driven member integral with the cam, a support, an intermediate member rotatablly supported in an eccentric circular cam integral with the support, a first coupling coupling the drive member with the intermediate member at a first position spaced from an axis of the driving shaft, and a second coupling coupling the driven member with the intermediate member at a second position angularly spaced from the first position with respect to the shaft axis. The first coupling has a movable connection with the intermediate member to permit variation in a distance of the first position from an axis of rotation of the intermediate member during operation.

Abstract: A valve actuating device for an engine having first and second engine valves for each engine cylinder. The valve actuating device comprises first, second and third cams which have respectively first, second and third cam profiles which are different from each other. The first and second cam profiles are for a low engine speed range. The third cam profile is for a high engine speed range. First and second rocker arms are supported on a rocker shaft and swingable respectively in accordance with the first and second cam profiles and are adapted respectively to make valve movement actions of the first and second engine valves. A third rocker arm is supported on the rocker shaft and swingable in accordance with the third cam profile of the third cam. The third rocker arm is put into a first state to be simultaneously connected with the first and second rocker arms to serve as a single body, and a second state to be disconnected from the first and second rocker arms.

Abstract: A rocker arm which supporting a free cam follower is rotatably supported by an engine-cylinder-mounted rocker shaft to lift cylinder valves against valve springs. The rocker arm and the free cam follower are in cooperation with first and second cams on a camshaft. A lever is supported by the rocker arm and has a locked position wherein the lever is in driving engagement with the free cam follower to provide a positive motion connection between the free cam follower and the rocker arm and a released position wherein the lever is out of driving engagement with the free cam follower to provide relative motion of the free cam follower to the rocker arm. A hydraulic piston and a release spring cooperate with each other to shift the lever between the locked position and the released position. For adjusting the shifting operation in timed relationship with motion of the rocker arm, a latch is arranged to restrain motion of the hydraulic piston when the rocker arm is unlifted and until the rocker arm is lifted.

Abstract: A camshaft has a front part forming a journal part for a wheel of a timing pulley (a drive member). A stub shaft (a driven member) is secured to the front of the camshaft and disposed within a cylindrical body of the timing pulley. An annular slide is disposed and coacts with the cylindrical body and the stub shaft for phasing action. The magnitude of axial movement of the slide determines the magnitude of relative rotation between the timing pulley and stub shaft. Fixedly attached to a timing pulley cover is a body formed with a cylindrical bore receiving a piston and a valve bore receiving a spool of a valve for regulating supply of fluid to and discharge thereof from a pressure chamber defined by the piston in the cylindrical bore. A motor is fixedly attached to the timing pulley cover is coupled with a worm of a worm gearing including a worm gear. A motion connection between the piston and the slide is established by a piston rod, a push rod, a cross bar and a slide spring biasing the slide.

Abstract: According to a control strategy, a cylinder valve control device is monitored and operation of the engine is modified. The cylinder valve control device includes a driving shaft driven by the engine to drive an intermediate member which in turn drives a cam arranged to open an engine intake valve, and a driver which is operative in response to a command to vary an amount of eccentricity of the intermediate member with respect to a shaft axis of the driving shaft. During one mode of engine operation, the intermediate member is supported in a support for rotation about an axis in eccentric condition with respect to the shaft axis to accelerate and decelerate the cam with respect to rotation of the driving shaft. During another mode of engine operation, the intermediate member is in concentric condition with respect to the shaft axis to provide a synchronous motion of the cam with rotation of the driving shaft. In response to the eccentricity of the intermediate member, the engine operation is modified.

Abstract: A valve drive for an internal combustion engine, comprises a valve train which is operable in a first state to transfer the rotational motion of a low lift cam lobe to the reciprocating motion of a cylinder valve against a valve spring. The valve train is also operable in a second a sate to transfer the rotational motion of a high lift cam lobe to the reciprocating motion of the cylinder valve against the valve spring. The valve train includes a cam follower arranged to move between a first position in which the cam follower is driving relation with the low lift cam lode and a second position in which the cam follower is in driving relation with the high lift cam lobe. An actuator and a return mechanism are arranged outside of the valve train to shift the cam follower between the first and second positions thereof.

Abstract: A device is proposed which enables a cam controlling an internal combustion engine valve to be moved relative to its driving shaft. A drive member is rotatable with a driving shaft, and a cam for co-axial rotation relative to the driving shaft. An intermediate member is mounted in a support for rotation so as to rotate eccentrically with respect to an axis of the driving shaft. The support is held for movement within a plane perpendicular to the shaft axis. A control rod is drivingly associated with the support and driven by an actuator.

Abstract: A control system for a four-cycle internal combustion engine controls a cam drive mechanism for an intake valve such that a cam of the cam drive mechanism maintains a valve open duration of the intake valve at a short valve open duration in response to a shift from engine operation at low speed with low load to engine operation at low speed with high load, and the cam increases the valve open duration of the intake valve in response to a shift from engine operation at low speed with low load to engine operation at low speed with middle load that is higher than the low load but lower than the high load.

Abstract: An engine valve control mechanism is disclosed in which the eccentricity of an intermediate member can be varied by a pivotable support and a valve lift of a cylinder valve is varied in response to the varying eccentricity such that a reduced valve lift is produced during operation with the intermediate member held eccentric with a driving shaft which drives, via the intermediate member, a cam which actuates the valve.

Abstract: An improved control device for intake and/or exhaust valves of an internal combustion engine includes a small circumference portion defined in a drive shaft at a location corresponding to that of an annular member which is eccentrically displaced for changing a rotational phase of the cams. According to this a degree of displacement of the annular member may be increased and control the cams, and thereby the engine valves, may be enhanced. Further, the cam lobe of each cam is formed such that side portions thereof are asymmetrical with respect to a center line of the cam for favorably affecting valve opening and closing timings. In addition, an improved lubricating arrangement for enhancing smooth operation and improved engine performance.