exhaust valve

English Thesaurus

1. a valve through which burned gases from a cylinder escape into the exhaust manifold (noun.artifact)

hypernym	:	valve,
definition	:	control consisting of a mechanical device for controlling the flow of a fluid (noun.artifact)

part meronym	:	exhaust, exhaust system,
definition	:	system consisting of the parts of an engine through which burned gases or steam are discharged (noun.artifact)