Intake system for four-cycle engines

摘要

An induction system for a four-cycle internal combustion engine that improves charging efficiency, power and torque at idle and low speed. A check valve is provided in the intake passage for precluding reverse flow under these running conditions. In addition, a plenum chamber is provided that communicates with the intake passage downstream of the check valve for improving power and torque throughout the entire load and speed range of the engine.