| 摘要 |
PROBLEM TO BE SOLVED: To successfully stabilize stratified combustion that causes delay of ignition timing in an internal combustion engine.SOLUTION: An internal combustion engine that includes a tumble flow generated in a combustion chamber has: an ignition plug disposed on an upper wall surface of the combustion chamber; a cylinder injection valve for injecting fuel into the combustion chamber so that fuel spray is conveyed by the tumble flow to a portion around the ignition plug when a stratified combustion operation is performed; a piston 12 having, on a crown surface 12a, two grooves that are an outer groove 38 and an inner groove 40 as recessed portions each formed to extend in an orthogonal direction D of an axis L1 of a piston pin hole 12b and having a depth changing in the direction of the axis L1; and an air current control valve 22 and an ECU for making a flow of intake air in an intake port uneven so that the intake air is guided toward the inner groove 40 relatively deep in the direction of the axis L1 when the stratified combustion operation is performed while the ignition timing is delayed from optimal ignition timing.SELECTED DRAWING: Figure 3 |
