RESTART DEVICE OF VEHICULAR ENGINE AND METHOD FOR CONTROLLING SAME

There is provided a system, in which, during an engine stop through an idle stop operation and when the engine is in a process of stopping, a starter is rotated preliminarily, and then the rotational speeds of a ring gear and a pinion are detected by the sensors to determine a plunging timing of the pinion. In such a system, a reverse rotation speed, determined by an action of the helical spline configuration and a plunging velocity of the pinion, is subtracted from the rotational speed of the pinion, determined by the rotational speed of a motor. A resultant rotational speed is converted to the rotational speed of the ring gear by using the reduction ratio of the pinion and the ring gear. Calculation is performed such that, when a difference between the converted rotational speed and the rotational speed of the ring gear is equal to or lower than 180 revolutions per minute, the pinion contacts the ring gear. The start of energization of the magnet switch is determined accordingly to perform the plunging operation of the pinion. This enables a quiet engagement of the pinion of the starter with the ring gear of the engine, while the engine is in the process of stopping and is still rotating.