Dual spark-plug ignition internal combustion engine with improved combustion chamber wall

摘要

Two spark plugs are disposed in each combustion chamber of an internal combustion engine to ignite the air-fuel mixture mixed with a considerably large proportion of the exhaust gases. The wall surface of the combustion chamber is formed so that only one spark plug can not be excessively cooled down by the stream of the cool air-fuel mixture inducted through the intake port of the engine.