A Framework for Model Based Detection of Misfire in a Gasoline Engine with Dynamic Skip Fire

A framework is proposed for model-based misfire detection in gasoline engines with dynamic skip fire by employing a novel control oriented engine model. The model-based techniques form compact description of plant behavior and have a number of well known benefits. The performance requirements and environment legislation resulted in a rigorous research on misfire detection due to which an extensive literature can be found for the problem of misfire detection in all-cylinder firing gasoline engines. Since there is no fix cylinder activation/de-activation sequence in dynamic skip fire engines. So, the problem of misfire detection in dynamic skip fire engines departs from its trivial nature. In the proposed framework, ‘cylinder skip sequence’ is also fed to the engine model along-with conventional engine inputs. The First Principle based Engine Model constructs the crankshaft angular speed fluctuation pattern for a given cylinder skip sequence. The crankshaft angular speed fluctuation pattern is shown for three cases which include, the conventional engine configuration, gasoline engine with dynamic skip fire and gasoline engine with dynamic skip fire having intermittent misfire condition. The simulation results are presented to show the efficacy of the proposed framework with the help of frequency domain components of the model output and normalized cross correlation during steady state and transient conditions.