Combustion chamber of an internal combustion engine

摘要

An internal combustion engine having an auxiliary combustion chamber connected to only the main combustion chamber via a connecting passage. The engine 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 shape squish area is formed between the spherical bottom wall of the third raised portion and the spherical rear face of the second raised portion. A recessed portion is formed on the top wall of the main combustion chamber at a position near the first raised portion. The open end of the connecting passage is arranged in the recessed portion. The spark plug is arranged within the recessed portion at a position near the open end of the connecting passage and outside of the extension of the connecting passage.