Driving Cycle Simulation for Heady Duty Engine Emission Evaluation and Testing

Driving cycle simulation of the heavy duty vehicle powertrain systems is presented as a methodological approach for evaluation of the engine operating points used for emission testing. This approach employs a backward facing method based on the quasi-steady approximation using the engine steady state characteristics. The driving cycle used in this study is extracted from the experimental data collected from the city buses in the real traffic conditions of the city of Tehran. The driving cycle is divided into several traffic conditions including congested, urban and extra-urban (highway). Several driving modes have also been considered including idle, cruise, deceleration and acceleration. The driving cycle simulation is then used to obtain the distribution of the engine operation for several driving cycles, traffic conditions and driving modes. Finally, the mapping from the driving cycle SAPM into the engine SLPM is employed to analyze the results. This study reveals that the common used 13-mode heavy duty engine test cycle is not necessarily compatible with the engine operating points for the city bus application, in particular at idle condition.