Intra-cylinder pressure sensor fault diagnostic device and intra-cylinder sensor sensitivity correction device provided with same

Abstract

An intra-cylinder pressure sensor fault diagnostic device that ensures an opportunity for fault diagnosis in a wide operation region, and can accurately detect an intra-cylinder pressure with a high S/N ratio. The fault diagnostic device for an intra-cylinder pressure sensor, which outputs a value corresponding to an intra-cylinder pressure of an internal combustion engine delays ignition timing so that firing timing comes after a compression top dead center to generate peaks of the intra-cylinder pressure before firing and after firing respectively. When the ignition timing is delayed, at least one of an output value of the intra-cylinder pressure sensor in the peak of the intra-cylinder pressure before firing (hereinafter, called a pre-firing output peak value) and a crank angle thereof is detected. A fault of the intra-cylinder pressure sensor is determined by using at least one of the pre-firing output peak value and the crank angle thereof.