FAILURE DETECTION APPARATUS FOR AN INTERNAL COMBUSTION ENGINE

A failure detection apparatus for an internal combustion engine includes failure detecting means (S22–S30) for detecting abnormality of fresh air quantity detecting means (air flow sensor) based on the result of comparison between a fresh air quantity detected by the fresh air quantity detecting means (air flow sensor) and a fresh air quantity reference value set by fresh air quantity reference value setting means (S20), and a supercharger equipped with variable nozzles/vanes. The fresh air quantity reference value setting means sets the reference value (S16) in accordance with not only the operating state (engine speed Ne, fuel injection quantity Qf, etc.) of the engine but also a target vane opening set for the variable nozzles/vanes of the supercharger by target vane opening setting means (S12, S14).