Hollow valve for i.c. engine - with copper or aluminium tube expanded by heated organic material

摘要

Cooled hollow valves for internal combustion engines are produced by introducing in the hollow valve stem an enclosed tube of copper or aluminium which contains a charge of a thermally decomposable material. The vapours produced by the charge exert such a pressure that the tube is expanded and forced into intimate contact with the hollow valve. If the charge consists of polyethylene, this produces CH2 which is inert relative to copper. This eliminates all the risks in the operation and difficulties in the handling of sodium filled valves.