Intake system for an internal combustion engine

摘要

An intake system for an internal combustion engine, the system having an air tank of a predetermined volume. The tank is connected to a intake pipe of the engine via a first connecting pipe. The tank is connected to an air cleaner via a second connecting pipe. A control valve is arranged at a position where the first connecting pipe is connected to the intake pipe so as to change the effective intake pipe length. The control valve is operated in response to the operating conditions of the engine to select the effective intake pipe length capable of attaining increased volumetric efficiency.