US Patent 7258089 Variable valve unit for vee shape engine

A rocker arm mechanism opens and closes an intake valve. The intake valve is driven by cam of a cam shaft. The rocker arm mechanism is provided in each of bank. The rocker arm mechanism has a structure which changes a phase of the intake valve while displacing a portion driven by the cam to a circumferential direction of the cam shaft. A structure provided with an inversion mechanism inverts a rotating direction of the camshaft of one bank with respect to a rotating direction of the camshaft of the other bank. A variable valve unit having the simple and same structure can be used in both banks. A phase is varied so that a valve closing timing is set larger than a valve opening timing for each bank.