Optimal Energy and Emission Management of a Diesel Hybrid Electric Vehicle Equipped with a Selective Catalytic Reduction System

This paper deals with the problem of obtaining the optimal energy and emission management strategy for a diesel hybrid electric vehicle. The vehicle is assumed to be equipped with a selective catalytic reduction device for the removal of harmful NOx emissions.

The authors present a model-based procedure: The energy flows of the hybrid vehicle are modelled in a standard way, while the engine-out emissions are calculated based on a temperature-corrected engine map. For the simulation of the SCR system a combination of two existing first-principle physical models is used. The optimal energy and emission strategy for a given driving cycle is then obtained using dynamic programming.

In terms of results, three case studies are presented. One case study illustrates the trade-off between fuel consumption and tailpipe NOx emissions for various relative weights of these objectives. The second case study investigates the influence of the size of the SCR system on fuel consumption and tailpipe NOx emissions. The third case study shows the influence of neglecting the thermal effects and the emission considerations in the derivation of the optimal control strategy.