IC engine with variable compression ratio - has spring loaded auxiliary piston to prevent detonation at low speed

摘要

Internal combustion engine with high compression ratio is susceptible to pre-detonation when operating at low speed. This is avoided by installing a small auxiliary piston (3) in the cylinder head (7). This piston (3) is loaded by a spring (6) inside a housing (4). When running at normal speed the auxiliary piston (3) is held flush with the inner surface of the cylinder head (7) by a bolt which engages the piston rod (5). At low speed the bolt is withdrawn by a solenoid (8) allowing the auxiliary piston to be pushed upwards against the spring (6) and reduce the effective compression ratio of the engine.