Self-adjusting piston for variable compression IC engine - has oil relief valve between sections directly in inner section wall

摘要

The piston has an outer section (12) which works in the engine cylinder and an inner section (14) which is pinned to the connecting rod (26). The outer section can move axially over the inner section to alter the effective length of the piston and thus vary the compression ratio. The movement is controlled by oil admitted through the connecting rod and a valve (56) in the inner piston to two spaces (30, 32) between the inner and outer sections. The pressure relief valve (92) for the upper space is built directly into the wall of the inner piston section (14). The valve seat is in a sleeve (94) which can be adjusted axially within the wall of the section and locked in position by a grub screw (105).