| 摘要 |
PROBLEM TO BE SOLVED: To enable proper stratified charge of a mixture gas around an ignition plug at a stratified charge combustion operation without reducing reliability of the ignition plug with simple constitution. SOLUTION: In the spark ignition type direct-injection engine constituted so that the central portion of a ceiling of a combustion chamber higher than the peripheral edge is formed on a cross section seen from the direction where a tumble flow is rotating in the clockwise direction, the ignition plug 16 is arranged at this central portion, a fuel injection valve 18 is arranged on the left of the peripheral edge, and ignition is made in the state where a mixture gas is stratified around the ignition plug 16 by injecting fuel opposing the tumble flow generated in the combustion chamber at the stratified charge combustion operation, a recess part 27 having a bottom face along which the tumble flow goes on the piston top face and opened right and left with the cylinder axis inbetween is formed on the above cross section, and a stepped part 28 for deflecting the tumble flow upward is formed at a position where this recess part is offset to the left of the cylinder axis Z.
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