Identification of Emission Models in a Spark

A procedure for the identification of emission models for the design of optimal control of spark ignition engines is presented. The procedure is based on a decomposition technique for the definition of optimal model structure with limited number of parameters. A two step scheme has been built: in the first step the available physical models, based on a multi-zone thermodynamic model with emission sub-models, are parametrized and an intermediate model, based on Taylor approximation, is derived in order to describe the non linear influence exerted by the physical parameters; in the second step the physical parameters are modeled by means of non linear regression, taking into account the effect of operating engine variables