How to say free piston engine in Mandarin Chinese Pinyin

How to say free piston engine in Putonghua|Mandarin Chinese Pinyin

Useful Expressions or Words (English)	Chinese Pinyin & Chinese Symbol Translation	Sound
free piston engine	zì 自 yóu 由 huó 活 sāi 塞 shì 式 fā 发 dòng 动 jī 机

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