Abstract: A valve operating mechanism for an internal combustion engine for varying the operation of the valve dependent on engine operating conditions. A first rocker arm movable to follow a first cam and a second rocker arm movable to follow a second cam corresponding to a higher speed operating condition than that of the first cam are pivotally supported on a rocker arm shaft. A first connection switching device capable of switching the connection and disconnection between the third and first rocker arms and a second switching device capable of switching the connection and disconnection between at least one of the first and third rocker arms and the second rocker arm independently from the first connection switching device, are disposed at locations displaced circumferentially relative to the rocker arm shaft.

Abstract: A valve operating mechanism for an internal combustion engine for varying the operation of the valve dependent on engine operating conditions. A first rocker arm movable to follow a first cam and a second rocker arm movable to follow a second cam corresponding to a higher speed operating condition than that of the first cam are pivotally supported on a rocker arm shaft. A first connection switching device capable of switching the connection and disconnection between the third and first rocker arms and a second switching device capable of switching the connection and disconnection between at least one of the first and third rocker arms and the second rocker arm independently from the first connection switching device, are disposed at locations displaced circumferentially relative to the rocker arm shaft.

Abstract: A self-expanding mount controls transmission of vibration of a vibration source to a base. A main liquid chamber is defined between a resilient member fixed to the vibration source or the base and a casing fixed to the base or the vibration source. A metallic bellows is driven in response to a control signal corresponding to vibration of the vibration source, cause a variation in the pressure of liquid within the main liquid chamber. This variation in the liquid pressure causes contraction and expansion of the resilient member to thereby control the transmission of vibration of the vibration source to the base. A cylinder is formed in the casing and defines part of the main liquid chamber. A driven member is received in the cylinder for axial displacement therein in response to the above control signal. The driven member may be a bellows or a piston.

Abstract: A fuel injection control system is provided for use in a cylinder injection/spark ignition type internal combustion engine in which fuel is injected directly into cylinders through respective fuel injection valves mounted in the cylinder heads. An ECU determines a desired fuel injection amount based upon the engine rotational speed and an engine load condition, determines desired fuel pressure to be supplied to the fuel injection valves and controls the actual fuel supply pressure relative to the desired fuel pressure. The ECU causes fuel to be supplied under the desired fuel pressure to each of the fuel injection valves, based upon the engine rotational speed and injected thereby into the corresponding cylinder when the crank angle of the engine falls within a predetermined range in the vicinity of a top dead point of the cylinder corresponding to a compression stroke thereof. The predetermined crank angle range is set to a range of 20.degree. BTDC to 5.degree. ATDC.

Abstract: An OHC type internal combustion engine with four valves per cylinder in which a single cam shaft extending longitudinally is engaged by individual rocker arms for each valve for pivoting those rocker arms to actuate the valves. The pairs of exhaust valves on one side of the engine are actuated by rocker arms mounted on a continuous rocker arm shaft. The intake valve rocker arms are mounted on a plurality of short shafts supported by their ends. A cam shaft holder is positioned over each cylinder and they serve to rotatably support the cam shaft, support the continuous rocker arm shaft, support the ends of the plural rocker arm short shafts, and to permit access to the spark plug for that cylinder. The spark plug has its electrodes located at the center of the combustion chamber and is inclined outwardly for access from between the intake valve rocker arms for that cylinder.

Abstract: A supporting structure for rocker arms for engine valves includes an engine having a cylinder head, a valve provided on the cylinder head and adapted for either of intake and exhaust purposes, a valve-operating mechanism for operating the valve, the valve-operating mechanism including a rocker arm abutting on the top of the valve, to thereby operate the valve, and a pivotal structure for pivotably supporting one end of the rocker arm. The pivotal structure comprises a ball-like portion, a spherical concave portion shaped in a form substantially correspondent to the ball-like portion and engaged with the ball-like portion, and an elastic member disposed at an aperture end of the spherical concave portion and adapted to hold the ball-like portion in the spherical concave portion.

Abstract: A cylinder head for DOHC type internal combustion engine with a center block integrally formed over each cylinder with portions for supporting the rocker arm bearings and a central hole for receiving the ignition plug. Two main oil supply passages are integrally formed in the head and extending longitudinally on either side of the plug holes for supplying lubricant to the rocker arm bearings and the camshaft bearings on each side.

Abstract: The curved surface of the semi-spherical recess is defined such that a center of the curvature of the semi-spherical recess in a longitudinal section including a center line of the semi-spherical recess deviates from the center line, and a radius of curvature of the recess is greater than a radius of curvature of the spherical fitting portion.

Abstract: Blow-by gas passages are formed on one side of the cylinder block and cylinder head of an internal combustion engine and spaced longitudinally of its crankshaft. The passages extend from the interior of the crankcase to a location above an upper face of the cylinder head, one of the passages being provided with a mounting port for an oil separator. The other blow-by passage is also connected to the separator, and the separator is connected to the intake system of the engine.