Internal combustion engine equipped with an auxiliary combustion chamber

摘要

An internal combustion engine comprises a main combustion chamber and an auxiliary combustion chamber which are interconnected to each other via a connecting passage. The spark plug is arranged in the connecting passage. The engine further comprises a first raised portion formed on the inner wall of the cylinder head, a second raised portion formed on the top face of the piston at a position opposite to the first raised portion with respect to the axis of the piston, and a third raised portion formed on the inner wall of the cylinder head above the second raised portion. A first flat squish area is formed between the flat peripheral top face of the piston and the flat bottom face of the first raised portion. A second spherical shell shaped squish area is formed between the spherical bottom wall of the third raised portion and the spherical rear face of the second raised portion. The intake port has a helical shape for creating a swirl motion rotating about the vertical axis of the cylinder in the main combustion chamber at the time of the intake stroke.