Sohc type internal combustion engine

Abstract

A SOHC type internal combustion engine includes a pair of intake valves and a pair of exhaust valves. The intake valve driving means comprises a plurality of rocker arms disposed adjacent one another, including a pair of driving rocker arms operatively connected separately to the intake valves and a connection switchover mechanism capable of switching-over the connection and disconnection of the adjacent rocker arms in accordance with the operational condition of the engine. The exhaust valve driving means comprises a pair of exhaust valve-side rocker arms operatively connected separately to the exhaust valves and disposed on opposite sides of the intake valve driving means in positions opposed to said cam shaft, respectively. In the intake valve driving means, the opening and closing mode of the intake valves can be changed in accordance with the operational condition of the engine by operation of the connection switchover mechanism, thereby providing an improvement in output from the engine. The intake valve driving means is constructed compactly by disposition of the plurality of rocker arms constituting the intake valve driving means adjacent one another in the positions opposed to the cam shaft, thereby enabling an effective and compact construction of the connection switchover mechanism provided in the intake valve driving means.