Nippon Piston Ring Co., Ltd.

Masataka Okano

Noriaki Chida

Provided is a piston ring () comprising a sliding surface () covered with a Cr&#x2014;B&#x2014;V&#x2014;N alloy film (), wherein a B content is within a range of 0.1-1.5 mass % inclusive, a V content is within a range of 0.05-1 mass % inclusive, and a ratio [B content/V content] is within a range greater than 1 and 30 or less, thereby achieving a piston ring () having higher wear resistance, cracking resistance, and peeling resistance. This alloy film () preferably further includes Ti, the Ti content being within a range greater than 0 mass % and 8 mass % or less. Such a piston ring () is preferably mounted on an engine that uses an alcohol fuel or an alcohol-containing fuel.

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Ichinoseki, Japan

Masataka Okano