Keywords: instantaneous emission modelling, modal emission modelling, dynamic emissions mapping, emission factors, vehicle modes, catalyst, vehicle emissions
Static and dynamic instantaneous emission modelling
Emission models can be categorised into three categories: average speed models; traffic situation models, used at macro-scale or meso-scale level (national, regional, city level); and instantaneous (modal) models, useful at micro-scale level (street, vehicle level). To improve the existing instantaneous emission models, some preconditions must be fulfilled: the emission signals should be measured on a 10 Hz basis, due to their frequency content. Additionally, the transport dynamics from the engine to the analysers must be compensated by time-varying approaches. With these preconditions fulfilled, a new static instantaneous emission model is developed and the improvement in quality is checked by comparing it statistically with older models. A dynamic instantaneous model, able to include the transient generation of emissions, is subsequently created and the quality of prediction of engine-out emissions is determined. When a catalyst model is added, more accurate predictions of emissions for vehicles with after-treatment systems should be obtained.