Patent ID: 8915228

Claim:
An engine automatic stop and restart apparatus for performing automatic stop control for an engine when an automatic stop condition is satisfied while a vehicle is running and performing restart control for the engine when a restart condition is thereafter satisfied, the engine automatic stop and restart apparatus comprising: a ring gear provided to a crankshaft of the engine; a pinion gear for transferring rotation of a starter motor for starting the engine to the ring gear; pinion-gear moving means for moving the pinion gear by power supply so as to achieve meshing engagement with the ring gear; and an engine control section for performing the automatic stop control and the restart control based on an rpm of the engine, wherein the engine control section is configured to: start the power supply to the pinion-gear moving means when the rpm of the engine becomes smaller than an rpm at which the meshing engagement between the pinion gear and the ring gear is possible while the engine is rotating by inertia as a result of satisfaction of the automatic stop condition; temporarily stop the power supply to the pinion-gear moving means when an increase in the rpm of the engine is detected based on a fact that an amount of change in the rpm of the engine exceeds a predetermined increase detection threshold value before time required for the pinion gear to come into abutment against the ring gear elapses after the start of the power supply to the pinion-gear moving means; and restart the power supply to the pinion-gear moving means when a decrease in the rpm of the engine is detected based on a fact that the amount of change in the rpm of the engine becomes smaller than a predetermined decrease detection threshold value after the power supply to the pinion-gear moving means is temporarily stopped.