Abstract: A valve driving device of an engine under the present invention is provided with a cam shaft for exclusive use of intake for driving intake valves and a cam shaft for exclusive use of exhaust for driving exhaust valves. At least either the intake valve or the exhaust valve is pluralized and a transmitting member is trained between the cam shaft with more valves to drive and an engine output shaft. Gears to mesh with each other are provided on said two cam shafts. Under the above composition, only one pulley on the driven side or only one sprocket is required and therefore compactness of the engine can be realized. Also, rotation of the cam shaft having more valves to drive and large torque fluctuation can be stabilized and reliability of gears can be improved, without reinforcing the gears.

Abstract: A multi-valve engine of the type having a line of cylinders, intake and exhaust camshafts, and rocker arms for operatively connecting valves to the camshafts includes a first valve group of three valves consisting of either intake valves or exhaust valves and a second valve group consisting of the other of either intake valves or exhaust valves. Each of the valves of the first valve group is oriented such that a valve stem thereof is inclined outwardly to one side of the line of cylinders, while each of the valve of the second valve group is oriented such that a valve stem thereof inclines outwardly to an opposite side of the line of cylinders. First hydraulic lash adjuster means for a centrally-located valve out of three valves of the first valve group is positioned closer to a bore center of the cylinder than the centrally-located valve, or on a delay side in the rotational direction of the camshaft.

Abstract: An oil pressure control apparatus for a valve driving system for an internal combustion engine, in which a main oil supply passage feeds oil to a hydraulic actuator of the engine valve driving apparatus. A control valve is provided for closing the oil supply passage. A bypass oil passage bypasses the control valve continuously. The control valve, when closed, regulates the oil pressure to below a predetermined value and the oil pressure is insufficient to actuate the hydraulic actuator. When the control valve is opened, responsive to an engine operating condition such as engine speed, oil pressure is above the predetermined value, and the hydraulic actuator is actuated rapidly to shift the valve driving system from low speed to high speed operation.

Abstract: Engine valve driving apparatus including a camshaft rotatable with a crankshaft of the engine with a movable cam member supported in sliding fit by the camshaft for axial movement but prevented from any rotation relative to the camshaft. An engine valve is driven by the movable cam member, and a hydraulic system axially shifts the movable cam member between an operative position where the movable cam member is brought into cooperation with the engine valve and an inoperative position where the movable cam member is completely out of cooperation with the engine valve. The hydraulic system causes the shifting movement of the movable cam member according to engine operating conditions so that the engine valve is driven at different speeds or different timings.