Rotary valve assembly for an internal-combustion engine.

摘要

A rotary valve assembly for an internal combustion engine which comprises a metallic or ceramic sealing sleeve (40) rotatably mounted inside a bore of an engine head which houses the valve assembly. The sleeve has a port (44) for periodic communication during rotation of the sleeve with inlet and outlet passages disposed in the engine head, a lower end of the sleeve being open and communicating with an engine cylinder in which a piston reciprocates and an upper end of the sleeve being sealingly closed. The sleeve is split longitudinally over its entire length by a slit (46) which is aligned with the port and a valve mechanism is disposed in the head above the upper end of the sleeve and is adapted by suitable drive trains to rotatively drive the sleeve by engaging a driving formation (48) located at the upper end of the sleeve. An exchangeable compression element (74) can be attached inside the upper end of the sleeve to a valve mechanism to set the required compression ratio of the engine. Without removing the head the sleeve can be exchanged or adjusted to vary valve timing and the element can be exchanged to vary compression ratio.