The
sleeve valve is a type of
valve mechanism for
piston engines, distinct from the usual
poppet valve. Sleeve valve engines saw use in a number of pre-
World War II luxury cars and in the United States in the
Willys-Knight car and light truck. They subsequently fell from use due to advances in poppet-valve technology, including sodium cooling, and the Knight system double sleeve engine's tendency to burn a lot of lubricating oil or to seize due to lack of it. The Scottish
Argyll company used its own, much simpler and efficient, single sleeve system (Burt-McCollum) in its cars, a system which, after extensive development, saw substantial use in British
aircraft engines of the 1940s, such as the
Napier Sabre and
Bristol Hercules and
Centaurus, only to be supplanted by the jet engine.