Mazda Motor Corporation

Kolbenschmidt K. K.

Yoshikazu Nishiyama

Hiroaki Muranaka

Kazuyuki Teshima

Hiroyuki Takeshige

The present invention provides a piston for a spark-ignition engine, comprising: a land part, an upper surface part of which has a crown partforming a combustion chamber; a pair of skirt partsextending downward from a peripheral part of the land partand facing each other in a radial direction thereof; a pair of sidewall partscoupling side end parts of the pair of skirt partsto each other; and a pin boss partthat is formed in each of the sidewall parts. The present invention can inhibit the generation of HC produced at the time of combustion, while thermally protecting a top ringfitted into a top ring grooveon an outer circumferential surface of the land part. The crown partis configured by a flat base surfaceand a bulging partbulging upward above the base surface, and a thinned partprovided in the land partis formed deep such that the deepest part thereof is positioned inside the bulging part

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Higashihiroshima, Japan

Yoshikazu Nishiyama