Cylinder Air Rate Prediction During Engine Start and Crank-to-Run Transition

Predicting cylinder fresh air charge for fuel dynamics control of automotive PFI engines during engine start and crank to run transition is a critical yet difficult task. Without a precise cylinder air charge prediction and a proper prediction-error handling scheme, realization of precise fuel dynamics control is difficult, particularly in terms of simultaneously reducing engine-out hydrocarbon emissions and ensuring engine startability. This work presents a scheduled cylinder air rate prediction scheme that achieves accurate prediction of the cylinder air rate in normal engine starts while also obtaining smooth prediction under abnormal engine start conditions. Results are presented for several start conditions in comparison to actual calibration test data.