SPARK IGNITION ENGINE

摘要

A spark ignition engine capable of operating even with a leaner air-fuel mixture to achieve stable ignition and combustion performance. An ignition plug (7) is fitted to a cylinder head (1) through a sleeve (6), and the ignition electrode (7a) of the ignition plug (7) is disposed in a cylinder (2), facing a single chamber type combustion chamber (5). The sleeve (6) is formed in a blind cylindrical shape, an auxiliary chamber (10) storing the ignition electrodes (7a, 7b) of the ignition plug (7) is formed at the bottom part of the sleeve (6), and a nozzle hole (6a) allowing the auxiliary chamber (10) to communicate with the combustion chamber (5) is formed in the bottom part of the sleeve. The bottom part of the sleeve (6) is projected from an explosion surface (1a) to the inside of the combustion chamber (5) and the position (12) of ignition by the ignition electrode (7a) is set near the explosion surface (1a).