Cylinder Flow Estimation

The performance of air charge estimation algorithms in spark ignition automotive engines can be significantly enhanced using advanced estimation techniques available in the controls literature. This Chapter illustrates two approaches of this kind, that can improve the engine cylinder flow estimation. The first approach is based on an input observer while the second approach relies on an adaptive estimation. Assuming that the cylinder flow is nominally estimated via a speed-density calculation, and that the uncertainty is additive to the volumetric efficiency, the straightforward application of an input observer provides an easy-to-implement algorithm that corrects the nominal air flow estimate. The experimental results presented in this Chapter point to a sufficiently good transient behavior of the estimator.