Control system of exhaust for internal combustion engine

摘要

Exhaust system control apparatus for internal combustion engine having an exhaust line and a branch line thereon, and an opening and closing valve on said branch line adapted to open when the engine operates at low speed and to close when the engine operates at high speed. The ratio between the cross-sectional areas of the branch line and the exhaust line is about 0.6 to 0.8.