(automotive) A type of internal combustion engine design which has the inlet and exhaust valves in the cylinder head (and therefore above the piston). The camshaft can be beside the pistons (with pushrods and rockers operating the valves) or above the valves, with the latter usually referred to as overhead cam.

(automotive) A type of internal combustion engine design which has the inlet and exhaust valves in the cylinder block beside the piston. The cylinder head is then a simple dome extending across the valves and piston.

plural of relief valve

A safety valve that relieves pressure when it becomes high but before it becomes dangerous.

A liquid stop valve in which the stopper is formed by locally freezing the stopped liquid itself.

plural of tricuspid valve

plural of freeze valve

plural of thermionic valve

plural of valve oil

A valve designed to open when subjected to a given amount of pressure. Also used figuratively.