Turbo-down-sizing is one of methods to improve fuel economy and engine performance. But, it causes higher torquefluctuation and vibration in engines. So, it is necessary to increase rotational moment of inertia of flywheel to make torquefluctuation and vibration small, but it means mass increase and decrease fuel economy. So, in this study, by adding some masto flywheel at local points, it was studied to reduce toque variation under low rotational moment inertia and mass.