Influence of highway traffic flow condition on pollutant emissions of diesel passenger cars using driving simulator

In the last 20 years the attention of international organizations towards air pollution has been improved, leading to definition of laws and regulations. In order to evaluate strategies and policies, forecasting tools have been adopted by institutions. Currently, the estimation of traffic emissions is based on static models, in which the amount of pollutant is computed as a function of average parameters (average speed). The well-known traffic increase of the recent years has significantly changed the actual flow conditions, producing a strong rise of interferences. As this facet affects the operating condition of each vehicle, the use of a standard emission model at high traffic interference can lead to some inaccuracies. In such cases, instantaneous emission models introduce deeper capabilities; essentially, the pollutant prediction is directly tied to the engine vehicle operation point in real-like traffic condition. This second modeling approach has been adopted in the current work. A complete lumped parameter vehicle model has been built to be used as a virtual on-road emission/fuel consumption test unit. Investigations have highlighted the dependence of emission level and fuel consumption on drivers’ behavior; indeed, the analysis took advantage of the experiments carried out in the virtual reality laboratory: on a typical highway geometry, three different flow conditions have been simulated. In the present study has been highlighted the relationship between drivers behavior and the emissions of a diesel compact passenger car. Finally, in order to assess the differences between static and instantaneous emission models, a comparative analysis has been carried out.