| Popis: |
Automotive emission regulations have sharply increased the calibration effort required to tune conventional fuel control algorithms for engine start and crank-to-run transition. This paper presents a model-based control approach with predictive fuel dynamics control that mitigates some of the calibration effort. Instead of using a static equivalence ratio blending approach to compute the fuel command during start and crank-to-run transition, the method suggests using scheduled in-cylinder fresh air charge prediction, individual cylinder fuel dynamics compensation (via direct inversion of a fuel dynamics model), and lost fuel correction. Misfire and poor starts are detected and mitigated using intelligent mode scheduling of the in-cylinder fresh air charge predictor, which includes special modes for misfire and poor start. The result is fault tolerant predictive fuel control, even in the face of misfire or poor starts. The scheme has been validated on production L4 and V8 engines over a wide range of operating conditions, and the paper presents selected results from that validation study. |
