Kenneth P. Dudek

Predictive fuel dynamic control during engine start and crank-to-run transition for port fuel injected gasoline engines

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.

Modeling of nonlinear fuel utilization phenomena during engine start and crank-to-run transition

In addition to profound nonlinear effects of fuel dynamics, a phenomenon related to unbalanced mass conservation, characterized by inefficient fuel utilization, has a significant impact for control purposes in engine cold start conditions. In particular, the incomplete fuel utilization effect has been found to be nonlinear throughout the first few fueling cycles in a robust engine start. In order to understand the impact of this phenomenon on cold start emission control, this paper addresses these issues and approximates the diminishing return effect by means of a nonlinear model, based on experimental data. The resulting model, by properly capturing the utilized fuel effect, is promising for fuel dynamics compensation

A phase and frequency locking loop for engine air-fuel ratio control

In the spirit of the recent articles in [5], featuring classical controls revisited, a phase-lock loop concept is applied to an automotive air-fuel ratio closed-loop control system. This classical solution is analyzed, simulated, and experimentally implemented in a vehicle. The results demonstrate that the automobile engine air-fuel ratio system can be controlled to robustly meet emissions and driving performance requirements by using a simple classical control methodology with feedback from the common switching oxygen sensor.

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.

Control oriented modeling of a three way catalyst coupled with oxygen sensors

Modeling of three-way catalyst behavior in stoichiometric engines is a tovpic with significant depth of research which encompasses complex kinetics based models through highly simplified control-oriented models. For model based control design, one must consider the behavior of the catalyst in conjunction with the feedback oxygen sensors. These sensors have well known influences from exhaust gas species due to interaction with the catalyst which, if ignored, can cause significant difficulties in modeling and control. These effects have often been addressed by calibrating and validating catalyst models under simplified conditions in order to minimize errors. In this work, the root cause of many of these errors is investigated and experimental evidence presented. Additionally, ARMA and Hammerstein models are used to find a model capable of predicting the post-catalyst oxygen sensor response over realistic validation data.Copyright