A rotary valve internal combustion engine has a piston (1) connected to a crankshaft (3) and reciprocatable in a cylinder (2), a combustion chamber 4 being defined in part by the piston. The engine has a rotary valve (5) rotatable with a close sliding fit in a valve housing (8) fixed relative to the cylinder (2), the rotary valve having a valve body containing a volume (9) defining, in part, the combustion chamber 4 and further having in a wall part (11) thereof a port (1)2 giving, during rotation of the valve, fluid communication successively to and from the combustion chamber via inlet and exhaust ports (13), (14) in the valve housing. The rotary valve and the valve housing are both formed of aluminum.

A rotary valve internal combustion engine has a piston (1) connected to a crankshaft (3) and reciprocatable in a cylinder (2), a combustion chamber 4 being defined in part by the piston. The engine has a rotary valve (5) rotatable with a close sliding fit in a valve housing (8) fixed relative to the cylinder (2), the rotary valve having a valve body containing a volume (9) defining, in part, the combustion chamber 4 and further having in a wall part (11) thereof a port (1)2 giving, during rotation of the valve, fluid communication successively to and from the combustion chamber via inlet and exhaust ports (13), (14) in the valve housing. The rotary valve and the valve housing are both formed of aluminum.

Tophead Rotary Valve is used in internal combustion engines. Each valve would replace the two or more reciprocating popet valves currently use in each cylinder, thereby saving energy now wasted by reciprocating parts and the compression of the heavy springs used with popet valves. The rotating valve is a self-sealing valve which incorporates the combustion pressure itself to seal in that pressure. Prior designs of rotating valves had inherent problems with the expansion and contraction of metal caused by the heating and cooling of the valve and is housing, which then caused leakage of combustion pressure past the minute clearances necessary to maintain both lubrication and combustion gasses. The Tophead Rotary Valve can expand and contract vertically and horizontally while maintaining the same contact clearances with the cylinder head, thus overcoming that inherent problem. The engine itself will run much quieter and should be capable of higher RPMs. One Rotary valve per cylinder should also reduce the total number of parts needed. The Tophead Rotary Valve should increase engine efficiency by close to 10%, increasing gas mileage by the same percentage.