COMBUSTION CHAMBER IN DIRECT INJECTION COMPRESSION IGNITION ENGINE

摘要

PROBLEM TO BE SOLVED: To increase output of an engine while reducing toxic substances in exhaust. SOLUTION: A cavity 11 formed on the top face of a piston 10 has a shallow pan shape with a maximum diameter D that is 3.5 or more times larger than a maximum depth H. A bottom surface 12 of the cavity 11 has a mountainous portion 13 in the center and canyon portion 14 at the periphery thereof. The mountainous portion 13 has a moderate slope surface making the bottom surface 12 a continuously smooth curved surface. A central range having a diameter D/4 in the cavity 11 has a volume of 3.5% or less of the entire cavity 11. A fuel injection valve 16 is attached to a cylinder head concentric with the cavity 11. An intersection point is made by an axis center of the fuel injection valve 16 and a side face 15 of the cavity 11. At a top dead center of the piston 10, a height h from the intersection point to the top face of the piston 10 is half or less of the maximum height H.