Misfire Detection Based on Generalized Force Identification at the Engine Centre of Gravity

Misfiring creates a unique pattern attributed to a particular cylinder. When a misfire occurs, the balance of the engine is destroyed, and the generalized force at the centre of gravity (C.G.) of the engine is changed. In this paper, a new misfire detection method is presented based on the identification of the generalized force at the engine centre of gravity. Based on the engine acceleration signals at the mounts, through the use of the discrete spectrum interpolation method, the accurate amplitudes and phases of the acceleration signals are extracted, and then, the generalized force at the centre of gravity is calculated. Through analysing the main harmonic orders of the generalized force, the misfire features are accurately extracted and classified. Both the simulation examples and test bed results prove the effectiveness of the present method in detecting misfire faults in combustion engines.