Towards accurate instantaneous emission models

To address the needs of researchers and policy makers on local levels, a microscopic (i.e. at vehicle level) instantaneous emission model is being developed. This model aims to predict vehicle fuel consumption and emissions for a given speed profile, for various vehicle loads, slopes and gear shift scenarios. Instantaneous emission modelling maps the emissions at a given time to their generating “engine state”. To improve the existing models, an analysis of some preconditions must be made: owing to the frequency content of the engine and emission signals, they should be measured on a 10 Hz basis or faster. Additionally, the emission signals measured in a test are delayed dynamically, owing to the transport from the engine to the analysers. This transport must be compensated for by time-varying approaches. The modelling and compensation for the gas transport in dilution systems is presented here. With these preconditions fulfilled, new instantaneous emission models are developed and their improvement in quality is checked by comparing them with older models. Further improvements to describe the transient emissions of vehicles are sketched.