CYLINDER INJECTION TYPE SPARK IGNITION INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To obtain a cylinder injection type spark ignition internal combustion engine which can exert merits of stratified charge combustion and drastically improve fuel cost performance and output performance by forming a favorable stratified mixture in the neighborhood of an ignition plug at the optimal ignition timing upon forming the stratified mixture through direct injection of fuel into a combustion chamber during a compression stroke. SOLUTION: In a cylinder injection type spark ignition internal combustion engine 10, an inclined bottom face 42 of a recess groove 40 formed on the top face of a piston 18 is given descending gradient of a predetermined angle toward the advance direction of fuel injection, and a perpendicular side wall face 46 stands perpendicularly along the axis of the piston 18. The recess groove 40 is formed with its width gradually expanding along the advance direction of the fuel injection when seen on the plan. The fuel injection injected during the compression stroke flows along the recess groove 40 and can guide a favorable stratified mixture to the position of an ignition plug 30 stably at a wide injection timing of the compression stroke.