摘要 |
In an internal combustion engine a spark plug is disposed at a nearly central position of a combustion chamber formed between the underside of a cylinder head and a crown of a piston. Intake valves are disposed on one side of the cylinder head, while exhaust valves are disposed on the other side of the cylinder head. A recess having a generally rectangular bottom is formed in the piston crown and extends in a slap direction connecting the intake and exhaust valves. The recess has vertical wall portions for the formation of squish flows at both ends thereof in the slap direction. The vertical wall portions are contiguous to the piston crown and connect both ends of the recess smoothly with the piston crown. Thus, the piston realizes a stratified charge without obstructing reverse tumbling flows. The symmetric shape of the piston in a slap direction maintains the piston in good weight balance, and thereby eliminates mechanical loss, such as oscillation.
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