Abstract: A camshaft supported in an engine cylinder head structure has a low speed (lift) cam lobe and a high speed (lift) cam lobe. A rocker arm is supported by a hydraulic lash adjuster or a rocker shaft for pivotal motion and has a sub-rocker shaft and a pin. The rocker arm is drivingly engages the low lift cam lobe. A free cam follower is supported by the sub-rocker shaft and drivingly engages the high lift cam lobe. A latch lever supported by the pin has a latch position wherein one end portion of the latch lever is in locking engagement with the free cam follower and a latch release position wherein the one end portion of the latch lever is out of engagement with the free cam follower. A hydraulic piston received in bore is in driving engagement with the opposite end portion of the latch lever to urge the latch lever against a latch lever release spring towards the latch position thereof.

Abstract: A camshaft supported in an engine cylinder head structure has a low speed (lift) cam lobe and a high speed (lift) cam lobe. A rocker arm is supported by a hydraulic lash adjuster or a rocker shaft for pivotal motion and has a sub-rocker shaft and a pin. The rocker arm is drivingly engages the low lift cam lobe. A free cam follower is supported by the sub-rocker shaft and drivingly engages the high lift cam lobe. A latch lever supported by the pin has a latch position wherein one end portion of the latch lever is in locking engagement with the free cam follower and a latch release position wherein the one end portion of the latch lever is out of engagement with the free cam follower. A hydraulic piston received in bore is in driving engagement with the opposite end portion of the latch lever to urge the latch lever against a latch lever release spring towards the latch position thereof.

Abstract: A cam shaft assembly comprises a first coupling between a drive collar rotatable with a driving shaft and an annular disc at a first position spaced from the shaft axis, and a second coupling between the disc and said hollow cam at a second position angularly spaced from said first position with respect to the shaft axis. The first and second couplings are so spaced from the shaft axis that they are at varying distances from the axis of the disc during operation. Each of the first and second couplings has a movable connection with the disc to permit the variation in its distance from the axis of the disc. The disc is rotatably supported in a disc housing. A control rod is mounted for rotation and has an eccentric control cam which controls movement of the disc housing. A pivot shaft extends through the disc housing for allowing movement of the disc housing following the eccentric control cam in which said plurality of hollow cams are disposed.

Abstract: A control device controls intake and exhaust valves of an internal combustion engine. The device comprises a first flange provided by a cam shaft of the engine, which flange has a first radially extending elongate slit. A second flange faces the first flange with a certain clearance therebetween and is secured to a drive shaft to rotate therewith. The second flange has a second radially extending elongate slit. An annular member is disposed within the clearance and rotatable about an axis of the drive shaft. First and second pins are rotatably held by opposed sides of the annular member respectively. These pins are positioned at diametrically opposed positions with respect to a center of the annular member and slidably engaged with the first and second elongate slits respectively. A drive mechanism is employed for pivoting the annular member about a pivot axis eccentric to the axis of the drive shaft in accordance with an operating condition of the engine.

Abstract: An apparatus for actuating valves of an engine is disclosed. A cam shaft is supported by the engine and has at least one set of cams, e.g., two axially spaced low speed cams and a high speed cam between the low speed cams. A rocker shaft is supported by the engine. The rocker shaft supports a rocker arm for the valves. The rocker arm is driven by the low speed cams. The rocker arm has a sub-rocker shaft and a pin. A free cam follower is supported by the sub-rocker shaft and driven by the high speed cam. The apparatus comprises a mechanism including a lever supported by the pin of the rocker arm. The lever has a first position wherein the lever and the free cam follower are joined for attaining unitary motion of the free cam follower with the rocker arm. The lever has a second position wherein the lever and the free cam follower are separated for allowing relative motion of the free cam follower with respect to the rocker arm.

Abstract: A valve timing control apparatus including a rotary member drivingly connected to an engine crankshaft for rotation with the engine crankshaft, and a drive mechanism for transmitting rotation of the rotary member to a camshaft. The drive mechanism includes a piston member provided for reciprocation between first and second positions within the rotary member to rotate the camshaft with respect to the rotary member. The piston member defines first and second pressure chambers on the opposite sides thereof along with the rotary member. A valve member is provided for movement between third and fourth positions. The valve member is adapted to connect the first pressure chamber to a pressure source while connecting the second pressure chamber to a drain port to produce a pressure differential between the first and second pressure chambers to move the piston member toward the second position when the valve member moves from the third position to the fourth position.

Abstract: A valve timing control system includes of a cylindrical sprocket driven through a timing chain by a crankshaft of the engine. An arm is fixed to one end section of the camshaft and located inside the sprocket in a manner to extend generally diametrically. First and second plungers are slidably disposed respectively in first and second cylindrical bores formed in the sprocket. A hydraulic pressure chamber is defined between the bottom portion of each plunger and the bottom wall of the cylindrical bore so as to be supplied with a hydraulic pressure from a hydraulic pressure source. Each plunger is projectable toward the arm upon supply of the hydraulic pressure to the corresponding hydraulic pressure chamber thereby to cause the arm to rotate relative to the sprocket. Projections of the first and second plungers induce the rotational movements of the arm in opposite directions relative to the sprocket, respectively.

Abstract: An intake- and/or exhaust-valve timing control system for an internal combustion engine comprises a ring gear disposed between a rotating member having a driven connection with an engine crankshaft and a camshaft for changing a relative phase angle between the rotating member and the camshaft so as to control intake- and/or exhaust-valve timing of the engine depending on the operating state of the engine. The valve control system includes at least one pair of friction surfaces for creating friction torque between the rotating member and the camshaft so as to suppress a rapid change in relative rotational speed of the camshaft to the rotating member, and a spring for biasing one of the frictional surfaces to the other.

Abstract: An apparatus for use in a variable valve timing and/or valve lift system of an internal combustion engine is disclosed. The apparatus is easy to mount, install and adjust within a space available over a cylinder head of the engine. The apparatus comprises a rocker shaft, a first cam, a second cam, and a rocker arm pivotally mounted on the rocker shaft. The rocker arm includes a first cam follower arranged to engage the first cam and a second cam follower arranged to engage the second cam. The second cam follower is pivotally mounted on the rocker arm. A hydraulically operated locking bolt is movable from an unlocking position to a locking position. In the locking position, the locking bolt is received in bores formed in the rocker arm and in the second cam follower to establish a positive motion state wherein the rocker arm moves with said second cam follower as a unit.

Abstract: A valve timing control apparatus comprises a rotary member drivingly connected to the crankshaft for rotation with rotation of the crankshaft, and a drive mechanism for transmitting rotation of the rotary member to the camshaft. The drive mechanism includes a piston member provided for reciprocation to rotate the camshaft with respect to the rotary member. The piston member has a pressure chamber formed therein. The piston member is urged resiliently in a first direction. The piston member is movable in a second direction opposite to the first direction in response to a pressure introduced into the pressure chamber. The valve timing control apparatus also includes first and second conduit. The first conduit has a first outlet for connection to the pressure chamber. The second conduit has a second outlet for connection to the pressure chamber. The second outlet is spaced away from the first outlet in the first direction of movement of the piston member.

Abstract: A valve timing control system of an internal combustion engine having a camshaft for operating intake or exhaust valves. The valve timing control system is comprised of a cylindrical sprocket driven through a timing chain by a crankshaft of the engine. An arm is fixed to one end of the camshaft and located inside the sprocket in a manner to extend generally diametrically. An annular piston is movably disposed coaxially with the camshaft and inside the sprocket to define an oil pressure chamber. The piston is moved axially by controlling the oil pressure to be supplied to the oil pressure chamber, in accordance with an engine operating condition. At least three sliders are supported to the piston to move with the piston. Each slider has an inclined face which is in slidable contact with a side face of the arm. This inclined surface is adapted to push the arm to rotate around the axis of the camshaft when each slider is moved axially upon the axial movement of the piston.

Abstract: A valve mechanism for internal combustion engines of a type having a plurality of intake or exhaust valves for each cylinder is shown. A unique arrangement is applied to the valve mechanism for permitting the cam shaft to be positioned above the intake (or exhaust) valves. With the arrangement, the freedom in layout of an associated ignition spark plug in the engine is increased.

Abstract: A valve operating apparatus for an engine is disclosed. The apparatus includes a rocker arm operated by a first cam and a free cam follower operated by a second cam. The rocker arm has an integral barrel having a lost motion mechanism. A prop is slidably received by the free cam follower for movement between a first position in which the prop supports the free cam follower on the lost motion mechanism and a second position in which the prop supports the free cam follower on the barrel. A hydraulically operated piston moves the prop.

Abstract: An oil passage structure for a rocker-arm shaft for an internal combustion engine, comprises an outer cylindrical member for rotatably supporting rocker arms and an inner cylindrical member press-fitted into the outer cylindrical member. The inner cylindrical member employs at least one concavity having a given axial length for defining at least two axial oil passages.

Abstract: A main rocker arm which is pivotally mounted on a rocker shaft has one or more sub-rocker arms pivotally mounted thereon. The main rocker arm is arranged to synchronously open and close two poppet valves. Each of the sub-rocker arms can be selectively locked to the main one by way of hydraulically operated plunger arrangements. The main rocker arm is provided with a roller type cam follower which follows a low speed cam. The sub-rocker arms are provided with followers which engage high or very high speed cams. Lost motion springs which maintain the sub-rocker arms in contact with the cams are mounted on the main rocker arm.

Abstract: The pressure prevailing in a variable volume chamber which controls the compression ratio developed by a piston, is used control the movement of a valve which regulates the supply and draining of the chamber. During high load the high pressure is used to drain the chamber while under light load the lower pressure permits the chamber to be supplied with hydraulic fluid in a manner which tends to fill the same during induction phases and the like when the pressure in the cylinder is low.

Abstract: To induce high compression engine operation hydraulic fluid is fed into a variable volume chamber defined between an outer piston and an inner one which is reciprocatively disposed therein via a supply passage which includes a one-way valve. When low compression engine operation is required the pressure supplied to a valve chamber in which a spool valve is disposed is increased to the point whereat the spool valve moves to a position wherein the supply passage is closed and a drain and transfer passages are opened. The drain passage leads directly to the cylinder bore so as to enable the hydraulic fluid in the variable volume chamber to be vented unrestrictedly. The transfer passage permits a small amount of hydraulic fluid to flow through the variable volume chamber to the drain passage in a manner which cools the same and prevents degradation of the hydraulic fluid retained in the one-way valve and the like.

Abstract: At least one of two inlet valves provided per cylinder of a multi-cylinder internal combustion engine is operated using a variable valve timing device. This device is controlled in response to the load and rotational speed of the engine in a manner which reduces the lift of the valve at low engine speeds and stepwisely increases the same as the engine moves from one mode of operation to the other. In the event that only one valve is controlled this valve is selected to be the one other than that which generates swirl in the combustion chamber.

Abstract: There is provided an apparatus for driving intake and exhaust valves (12) of an internal combustion engine. The apparatus comprises a valve lift controlling means (16) connected to the valves to control the lift of the valves in response to the engine operating conditions, valve driving cams (13) fixed on a cam shaft (14) and being in contact with the valve lift controlling means (16), and a phase controlling means (23) arranged on the cam shaft (14) to control the relative rotational phase of the valve driving cams, i.e., the open and close timing of the valves (12) in response to the engine operating conditions.

Abstract: An engine valve operating system for an internal combustion engine comprises a rocker arm for transferring valve actuating effect from a driving cam to an engine valve such as an intake or exhaust valve. An elongate lever or fulcrum member is pivoted at its one end section and disposed in fulcrum contact with the side of the rocker arm opposite to the driving cam. Additionally, a hydraulic actuator is provided to control the pivotal location of the lever and therefore has a movable end section which is in contact with the other end section of the lever and movable in accordance with an engine operating condition, thereby greatly improving control response of the lever while rendering unnecessary a large capacity and sized actuator.