Rotary valve internal combustion engine

A rotary valve internal combustion engine, comprising:

• a piston connected to a crankshaft, wherein the piston reciprocates in a cylinder having a combustion end,
• a combustion chamber being defined in part by the piston and the combustion end of the cylinder,
• a valve housing fixed at an outer portion of the combustion end of the cylinder and defining a bore,
• a generally cylindrical rotary valve disposed in the valve housing,
• wherein the rotary valve is rotatable about a rotary valve axis with a close sliding fit in the bore in the valve housing,
• wherein the rotary valve has a hollow valve body having an interior volume forming a part of the combustion chamber,
• wherein the interior volume of the hollow valve body is subjected to combustion gases throughout the combustion process,
• wherein the rotary valve has, in a wall part thereof, a port giving, during rotation of the rotary valve, fluid communication successively to and from the combustion chamber via inlet and exhaust ports in the valve housing,
• wherein a sealing function is carried out between a surface of a main body of the rotary valve and a contiguous surface of the bore in the valve housing, and
• wherein the sealing function is carried out by a non-uniform profile between the valve housing and the main body determined by a temperature gradient along at least a portion of an axial length of the main body during operation, thereby maintaining a substantially constant clearance between the main body and the valve housing throughout the axial length of the main body.