Valve operating device for internal combustion engine

Abstract

An internal combustion engine intake valve operating mechanism for two intake valves having a separate driving rocker arm for each valve and two free rocker arms not connected to the intake valves. In a low-speed operating range, the driving rocker arms are in their disconnecting states from the free rocker arms, so that both intake valves are opened and closed by a second cam and a fourth cam. In a medium-speed operating range, the first free rocker arm and the first driving rocker arm are interconnected, so that one of the intake valves is opened and closed by a first cam and the other intake valve continues to be opened and closed by the fourth cam. In a high-speed operating range, the first driving rocker arm, the second free rocker arm and the second driving rocker arm are connected to one another, so that both the intake valves are opened and closed by a third cam. This reduces the equivalent inertial mass during connection of rocker arms and enables an increase in output and a reduction in fuel consumption in an internal combustion engine operating in multi-stages depending upon operating conditions of the engine.