Zero-dimensional modeling of NOx formation with least squares interpolation
Physical models of NO x formation are becoming more and more interesting in the area of combustion feedback control. The fact that cylinder pressure sensors are made available on the market enables fast and accurate calculations of heat release, which is an essential part of every physical NO x formation model. This article describes such a zero-dimensional model for a diesel engine using crank angle–resolved cylinder pressure to determine heat release. The model also incorporates the thermal effect of exhaust gas recirculation that is proven to have a major effect on NO x formation rates. The reaction mechanisms used to describe NO x formation rates are given by the well-known Zeldovich mechanism. The model output results given in this article show an average deviation of about 12.0% from acquired measured NO x data. The least squares interpolation approach indicates a negligible difference from the original model with an average deviation of 1.2% in 25 measurement points.