Real-time engine misfire detection method

摘要

A method of detecting internal combustion engine misfires by generating a predicted Karlovitz number as a function of different engine operating conditions such as the air fuel ratio (AFR), the engine speed, the amount of exhaust gas recirculation (EGR), spark-ignition (SI) timing and the airflow rate. The predicted Karlovitz number is then compared against the threshold Karlovitz number in which misfire occurs. The threshold Karlovitz number is determined from a model for misfire predictions in engines and is stored in the electronic engine controller (EEC). A misfire is reported if the predicted Karlovitz number is greater than the threshold Karlovitz number. In another aspect of the invention, the predicted Karlovitz number is generated from submodels of laminar flame speed, laminar flame thickness, turbulence intensity, and turbulence integral length scale.