Patent ID: 8499742

Claim:
A valve train of an internal combustion engine, comprising: a camshaft rotated in conjunction with a crankshaft of the internal combustion engine; a valve operating cam pivotally supported by the camshaft for operatively opening and closing an engine valve as an intake valve or an exhaust valve; a link mechanism for allowing a drive cam rotated integrally with the camshaft to swing the valve operating cam around the camshaft; and a drive mechanism for swinging the link mechanism around the camshaft; wherein opening and closing of the engine valve are started in a buffer section of the valve operating cam, and opening/closing timing of the engine valve is controlled by the drive mechanism swinging the valve operating cam around the camshaft via the link mechanism; and wherein without a provision of a buffer transition section and a buffer constant-speed section encountered at the time of transiting from a base circle to a cam lobe of the drive cam, an acceleration section where lift speed of the drive cam is increased and a constant-speed section subsequent thereto where the lift speed of the drive cam is constant are provided in place of the buffer transition section and the buffer constant-speed section, and the constant-speed section is provided to extend over an angle width including at least a maximum retard angle position of opening timing of the engine valve.