A Low Vibration Engine with Unique Counter-Balance Shafts

Subcompact cars generally use 4-cylinder engines, because of their advantages over 6-cylinder or 8-cylinder engines in production cost, engine size, weight, combustion efficiency, emission control, etc. The 4-cylinder engine, however, has an inherent shortcoming of second order vibration in the vertical and rolling directions, originating from the reciprocating masses and explosions in the engine.

A new in-line 4-cylinder engine with its vibration reduced to a level comparable to the 6-cylinder engine or rotary engine has been recently developed while retaining the advantages mentioned above. The engine incorporates a unique balancing system, which reduces the booming to a minimum in the vehicle passenger compartment.