Engine starting apparatus

摘要

The invention allows an accurate positioning to obtain a large inertia torque at starting. Especially, it prevents retrogradation that may occur when rotating an engine in the reverse direction by a motor and shutting down for positioning. At starting, the motor is energized by a first reverse rotation unit 111 to rotate the engine in the reverse direction to the position in the vicinity of the top dead center. After reverse rotation by the first reverse rotation unit 111, a second reverse rotation unit 113 energizes the engine further in the direction of reverse rotation with a small torque while reducing an exciting current to the motor. The exciting current is set to a degree that can obtain a braking effect for reducing retrogradation that may occur when the engine is stopped at a predetermined position within a high-load region after being rotated in the reverse direction. A stop position is set in advance between the top dead center on the compression stroke immediately before and the range of opening and closing operation of an exhaust valve, and whether or not the engine has reached the stop position may be recognized by a crank angle.