Patent ID: 7757545

Claim:
An apparatus for determining a failure of an in-cylinder pressure sensor mounted on an internal combustion engine, the apparatus comprising: in-cylinder pressure determining means for determining an in-cylinder pressure of the engine based on an output of the in-cylinder pressure sensor; means for determining a drift parameter based on the in-cylinder pressure, the drift parameter indicating an amount of drift included in the in-cylinder pressure; and a failure determining means for determining that the in-cylinder pressure sensor is faulty if the drift parameter is not within a predetermined range, in-cylinder pressure correcting means for correcting the in-cylinder pressure such that the in-cylinder pressure contains no drift, wherein the in-cylinder pressure correcting means further includes: correction means for correcting the output of the in-cylinder pressure sensor; integral means for integrating the output of the correction means to determine the in-cylinder pressure; and drift change rate calculating means for calculating a rate of change of drift contained in the in-cylinder pressure based on the in-cylinder pressure, and wherein the in-cylinder pressure correcting means feeds back the calculated drift change rate to the correction means, the correction means correcting the output of the in-cylinder pressure sensor with the drift change rate, and wherein the drift parameter determining means determines the drift parameter based on the drift change rate.