Abnormality diagnosis device and abnormality diagnosis method for supercharger

Abstract

The present invention provides an abnormality diagnosis device and an abnormality diagnosis method for a supercharger. In the abnormality diagnosis processing performed by an electronic control unit, a determination of having an abnormality of a turbo charger is made according to the fact that an actual supercharging pressure becomes equal to above the upper-limit supercharging pressure for preventing the over-speed rotation of the turbo charger. The throttle opening is reduced while the output torque of the internal combustion engine is decreased; on the other hand, the actual supercharging pressure is to be decreased by decreasing the rotation speed of the turbo charger. The electronic control unit prohibits the execution of the abnormality determination processing during the reduction of the throttle opening. Thus, a case of making a wrong determination of having the abnormality of the turbo charger through the abnormality diagnosis processing due to the temporary rising of the actual supercharging pressure is suppressed.