Dynamic Analysis of Hybrid Electric Vehicle Coupled with Waste Heat Recovery System Under Different Road Conditions

Hybrid trucks with low fuel consumption, low emissions and long range are considered to be effective fuel-efficient trucks. In addition, the engine of hybrid truck is still one of the main power sources. As a large amount of energy of engine is dissipated in the form of waste heat, waste heat recovery (WHR) system is still a promising energy saving solution. The operating conditions of trucks are complex and varied. In order to evaluate the energy saving effect of hybrid electric vehicle (HEV) coupled with WHR system under different road conditions (urban, suburban and highway), the dynamic model of hybrid truck equipped with WHR system was constructed in this study. The validity of the model was then verified by experimental data. The analysis of the vehicle performance and the energy saving effect of the WHR system was carried out based on the operation results of the dynamic model under different road conditions. The study results show that the effective operation interval of the WHR system is suburban and highway conditions, while the energy saving effect is not significant in urban conditions. When the target truck is fully loaded, the WHR system can save 6.36% fuel under mixed working conditions. The urban conditions are the superior operating range for the hybrid system. The combination of two energy-saving technologies enables efficient use of energy in all operating conditions. The study of the dynamic characteristics of the HEV-WHR system is of great importance for the practical application of both systems.