Patent ID: 7949462

Claim:
A control method of an internal combustion engine system having an internal combustion engine, an exhaust gas recirculation unit including an exhaust regulating valve that regulates a recirculation amount of exhaust of the internal combustion engine into an intake system of the internal combustion engine and a valve driver that drives the exhaust regulating valve to be open and close, and an exhaust purification unit including an exhaust purifying catalyst that purifies the exhaust of the internal combustion engine, the control method of the internal combustion engine system comprising: upon no occurrence of a closing abnormality that the exhaust regulating valve does not become in a totally closed state, controlling the internal combustion engine so that the internal combustion engine is operated with fuel injection where a fuel increase is performed to prevent that the exhaust purifying catalyst is overheated, in a case that the internal combustion engine is operated together with recirculation of the exhaust in a high-load operation range that is a range of rotation speeds more than or equal to a preset rotation speed and torques more than or equal to a preset torque, upon occurrence of the closing abnormality controlling the internal combustion engine so that the internal combustion engine is operated with the fuel injection where the fuel increase is performed to prevent that the exhaust purifying catalyst is overheated, in a case that the internal combustion engine is operated together with the recirculation of the exhaust in a preset range that is a larger range than the high-load operation range.