PURPOSE: To reduce the rolling moment of an engine by selectively controlling the operation of two balancers arranged separately in the direction of the central axis of a cylinder depending upon the operating condition of the engine so as that when one of the balancers is rotated the other balancer is stopped to rotate.
CONSTITUTION: The balancer device of an engine 19 is constructed so as that when the rotation rate of the engine 19 is smaller than a specified value a low rotation balancer 16 is rotated and a high rotation balancer 15 is stopped to rotate, and when the rotation rate of the engine 19 exceeds the specified value the high rotation balancer 15 is rotated and the low rotation balancer 16 is stopped to rotate. Thereby the position of the balancer is practically displaced in the direction of the central axis of the cylinder, that is equivalent to displace the position of the balancer in the direction of the central axis depending upon the operating condition of the engine 19, thus the rolling moment can be reduced significantly in wide operating condition even in operation range of low velocity high load or high velocity low load.
KAI YUKIMASA
HAMAI KYUGO
