Identification of the nonlinear, multivariable behavior of mechatronic combustion engines

The identification of the nonlinear dynamic behavior of combustion engines on test benches is described. A method, that is based on the combination of statistical stationary engine measurement (Design of Experiments - DoE) and dynamic identification techniques for nonlinear multi-input systems is shown. The dynamics are excited by several amplitude-modulated pseudorandom-binary-signals (APRBS), which act on the engine simultaneously, in order to allow a short measurement time period.To show the applicability of the described identification and modelling methods several models for a common-rail diesel engine with exhaust gas recirculation and variable geometry turbocharger (VGT) are shown, with five input variables and the outputs nitrogen-oxide emissions, opacity, air-fuel ratio (Lambda) and exhaust gas temperature.