| 摘要 |
PROBLEM TO BE SOLVED: To improve the homogenous combustion performance while ensuring the stratified combustion performance due to a cavity. SOLUTION: This piston of a direct injection spark ignition type internal combustion engine has a cavity 4 which is recessed and of which peripheral fringe part rises to form a ridge line 5 on a crown face of the piston 1. Here, an inclined face 3 which becomes lower continuously toward an outer peripheral side of the piston is formed on an outer peripheral side of the ridge line 5 without providing a flat part. An angleθof this inclined face 3 for a horizontal face is in a scope of 10 to 60 deg.. Moreover, a depth A of a flat part 4a on a bottom face of the cavity 4 from a flat reference plane 2 in an outermost peripheral part of the crown face of the piston is in a scope of 3 to 9 mm. Furthermore, when a height of an uppermost part of the ridge line 5 from the reference plane 2 is H, B=A+H is in a scope of 10 to 20 mm. |
