Four stroke internal combustion engine - has stepped piston to pre-compress different strength mixtures for admission through two valves

摘要

The engine has a piston (1) with a wider section at its bottom. The cylinder (8) has a corresponding wider section which forms an annular space (16) round the main section of the piston. Air or a weak mixture is admitted to the crankcase (11) through a non return valve (12) and compressed below the piston. A transfer passage (7) takes it to a chamber (8) above the main inlet valve (2). A rich mixture is admitted through a non return valve (13) to the annular cylinder space (16). It is compressed by the bottom section of the piston and discharged through a non return valve (14) into a chamber (9) above a second inlet valve.