Patent attributes
A control apparatus for an internal combustion engine can compensate for a variation of intake pressure resulting from various factors whereby a failure detection area can be expanded, and false detection can be prevented to enable failure determination for an EGR system with high reliability. The apparatus determines whether a vehicle is decelerating, forcedly opens and closes an EGR valve, and determines whether an EGR control device is in failure by comparing a pressure change index value based on intake pressures upon the forced opening and closing of the EGR valve with a failure determination value. The apparatus adjusts the intake pressure to a predetermined state before the EGR valve is forcedly opened and closed, whereby a failure determination can be always made based on the intake pressure whose variation was compensated for with the intake pressure becoming a predetermined characteristic to the number of revolutions per minute of the engine.
