Abstract: In a valve actuation apparatus of a multi-cylinder engine employing a drive shaft rotatably arranged to extend over a plurality of cylinders, a drive cam attached to the drive shaft, and a motion transmitter provided for each of the cylinders for converting a rotary motion of the drive cam into an oscillating motion, a rockable-cam structural member is provided for each of the cylinders in a state where a shaft is inserted through inner peripheries of the rockable-cam structural members, for operating engine valves by the transmitted oscillating motion. A plain bearing is provided in at least one axial position between the axially-spaced rockable-cam structural members. An inner periphery of the plain bearing is in contact with an outer periphery of the shaft, whereas an outer periphery of the plain bearing is in contact with an inner periphery of a bearing portion mounted on the engine.

Abstract: A valve lifter including a cylindrical portion, a crown portion having a crown surface, a chamfered portion formed on an outer periphery of the crown portion adjacent to an outer peripheral edge of the crown surface and tapered toward the crown surface, and a hard carbon film covering only the crown surface and the chamfered portion. The chamfered portion has a taper angle with respect to an outer peripheral surface of the cylindrical portion on which the hard carbon film is not formed, the taper angle being set to not more than 26.5°. The chamfered portion has a length extending from on a side of the crown surface toward a side of the cylindrical portion in an axial direction of the cylindrical portion, the length being set to not less than 1 mm.

Abstract: A valve lifter for an internal combustion engine includes a skirt portion formed in a tubular shape; and a crown portion formed integrally with an axially one end side of the skirt portion. The crown portion includes a crown surface configured to slide in contact with an outer circumferential surface of a cam. An axis of the crown portion is eccentric from a center of the cam in a width direction of the cam. The crown surface is formed in a spherical protruding shape to have its uppermost portion at a center of the crown surface. A protruding amount of the spherical protruding shape is set to range from 11 ?m to 50 ?m.

Abstract: A variable valve actuation apparatus of an internal combustion engine has a multinodular-link motion converter, to vary at least a working angle. A position of rotation of a control shaft, variably adjusting the attitude of the motion converter, is set, so that, at a peak lift during a valve opening period, an angle ?2 between an extension line of a line segment connecting a first fulcrum corresponding to a drive-eccentric-cam center and a second fulcrum provided on a rocker arm and a line segment connecting the second fulcrum and a third fulcrum provided on the rocker arm at a position different from the second fulcrum at a middle working-angle control mode is less than both an angle ?1 between the two line segments at a minimum working-angle control mode and an angle ?3 between the two line segments at a maximum working-angle control mode.

Abstract: An exhaust brake is incorporated with an internal combustion engine. The brake comprises an exhaust rocker arm actuated by an exhaust cam for operating an exhaust valve; a brake rocker arm actuated by a brake cam; a first contacting unit held by either one of the exhaust and brake rocker arms; a second contacting unit held by the other of the exhaust and brake rocker arms. The second contacting unit is contactable with the first contacting unit when an exhaust braking is needed. Only when the brake rocker arm is actuated by the brake cam upon need of the exhaust braking, there induces the contact between the second and first contacting units, which provides an integral action of the exhaust and brake rocker arms thereby to actuate the exhaust valve for establishing the exhaust braking.

Abstract: A decompression engine brake device is incorporated with an internal combustion engine. The device comprises an exhaust valve arranged to open and close an exhaust port of a combustion chamber of the engine. A valve stem extends from the exhaust valve. A valve lifter is slidably disposed in a cylinder head of the engine. The valve lifter has the valve stem contacting thereto. An exhaust cam disposed about an exhaust cam shaft is operatively engageable with the valve lifter to actuate the exhaust valve in accordance with a contour of the exhaust cam. An engine brake cam is defined by the exhaust cam. A hydraulically operating device is employed for inducing an operative engagement between the engine brake cam with the valve lifter thereby to actuate the exhaust valve in accordance with a contour of the engine brake cam.

Abstract: A method of producing a valve lifter to be used in a valve operating mechanism of an automotive vehicle. The valve lifter includes a skirt section, a crown section formed one end of the skirt section so that a cam of a camshaft is slidably contactable with the crown section, and a contacting section formed at an inside surface of the crown section and contactable with a valve stem of an engine valve.

Abstract: A mechanical valve lifter for an internal combustion engine comprises a head section having a recessed portion on an upper face thereof, a skirt section formed integral with the head section and adapted to be in sliding-contact with a lifter guiding bore in an engine cylinder head, a mechanical valve-clearance adjusting shim put in the recessed portion, an annular groove formed in an upper face of a bottom wall of the recessed portion of the lifter body, a first through-opening formed in the shim to communicate with the annular groove, and a second through-opening formed in the head section to communicate with the annular groove and to penetrate the head section. The annular groove and the second through-opening are formed in an essentially zero bending moment area midway between a central axis of the head section and a peripheral wall of the recessed portion.

Abstract: A valve lifter and processing method therefor include a valve lifter surface to be installed in a recess of a cylinder head of an internal combustion engine. The method includes a grinding step for beveling, or tapering, the circumferential end of a cylindrical wall portion of the valve lifter which slidingly contacts the recess. Excess material resulting from the beveling process is then removed for smoothing the beveled circumferential end. The smoothed surface is then coated with a hardening layer for abrasion protection and smoother operational movement. As a final step, the hardening layer may be polished for further enhancement of operating performance.

Abstract: A valve lifter of a valve mechanism for an internal combustion engine is provided with a crown-shaped valve lifter body which has a center plate with a recess. A fixing projection is integrally formed with the center plate and is formed along a side wall which defines the recess. An inner shim of a disc shape has a plurality of grooves to which the fixing projection is filled by caulking the fixing projection for fixedly connecting the inner shim with the valve lifter body. Therefore, the inner shim is easily and securely assembled in the recess of the valve lifter body so as not to generate the looseness between the inner shim and the valve lifter body while the assemble performance is improved.