CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

An EG-ECU stops a fuel cut when an engine rotation speed (NE) falls to a return rotation speed (NErtn) or lower during the fuel cut.  The EG-ECU forcibly opens/closes an EGR valve during the fuel cut and checks an EGR device for abnormality on the basis of the amount of change of suction pipe pressure caused by the opening/closing.  The EG-ECU stops the checking when the engine rotation speed (NE) falls to the forcible-stop rotation speed (NEoff) or lower during the checking.  When the EGR valve is not forcibly opened during the checking, the EG-ECU reduces the forcible-stop rotation speed (NEoff) compared to when the EGR valve is forcibly opened.  More specifically, when the EGR valve is not forcibly opened, the EG-ECU sets the forcible-stop rotation speed (NEoff) so that an allowance (?NEallw) with respect to the return rotation speed (NErtn) becomes smaller than when the EGR valve is forcibly opened.