Porting system for internal combustion engine

摘要

An induction system for an internal combustion engine wherein each chamber of the engine is provided with three intake ports and one charge former serves two of those intake ports while another charge former serves the other intake port. The charge formers employ a staged throttle valve arrangement so that the other charge former supplies the idle and low speed requirements and the first mentioned charge former comes into operation only at high speeds and loads. In accordance with another feature, the arrangement is provided for pairs of chambers and the single charge former serves two chambers.