Method and device for controlling stopping of engine

An engine stop control device comprising a controller configured to:

• stop an engine temporarily in response to a stop request for stopping the engine temporarily;
• reduce a quantity of oxygen stored in a catalytic converter by an air fuel ratio enrichment operation of controlling an in-cylinder air fuel ratio to be richer than stoichiometric, in response to the stop request;
• calculate the quantity of stored oxygen while the engine is operating;
• set an amount of air fuel ratio enrichment for the air fuel ratio enrichment operation, in accordance with a value of the quantity of stored oxygen calculated when the stop request occurs, such that the amount of air fuel ratio enrichment decreases as the value of the quantity of stored oxygen decreases;
• reduce an opening of a throttle valve disposed in an intake passage, in response to the stop request;
• and
• permit the engine to be stopped, in response to a condition that the reduction of the opening of the throttle valve causes an internal pressure of a section of the intake passage downstream of the throttle valve to reach a predetermined negative pressure, and the air fuel ratio enrichment operation causes the quantity of oxygen stored in the catalytic converter to reach a predetermined target value.