A control-oriented model for cylinder pressure in internal combustion engines

The cylinder-pressure modeling problem is formulated and a perturbation solution is presented. Control-oriented perturbation models (COPMs) for cylinder pressure in spark-ignited internation combustion engines are novel in that the smallest regions of realistic interest already include nonlinear effects which may be neglected, so linear perturbation is not adequate. Moreover, the crank angle frame of reference leads to a perturbation on the independent variable as well. These features require higher order local representations of vector-valued functions of several vector-valued variables, in a form suitable for computation. A COPM for cylinder pressure in a 1.8-L Opel Family II engine, with inputs of spark advance and air-fuel ratio, demonstrates that increased accuracy and consistency result from the increasing model degree made possible with these models