CONTROL DEVICE AND CONTROL METHOD FOR ONBOARD INTERNAL COMBUSTION ENGINE

A control device includes an injection control unit, an ignition control unit, an idling stop control unit, and a boost control unit. The injection control unit executes a rich reduction control that makes an air-fuel ratio richer than a stoichiometric air-fuel ratio when the engine operation has been resumed by resuming supply of fuel to a combustion chamber. Further, the boost control unit is configured to execute a valve-closing keeping control that keeps a wastegate closed until a condition for cancelling the valve-closing keeping control has been satisfied by the engine operation that was performed after closing the wastegate during execution of a fuel cut-off control.