Study on energy management strategy for a P2 diesel HEV considering low temperature environment

The research on energy management strategy (EMS) for hybrid electric vehicles (HEV) has been conducted widely. However, low temperature influence was ignored in these studies, which in turn affects HEV applicability in winter or extremely cold regions. In this study, low temperature energy management of a P2 diesel HEV was investigated. This key influence on diesel engine and lithium battery performance was considered and the corresponding EMS with HEV thermal state constrain was established. Firstly, mathematical models of the P2 HEV were built, including low-temperature preheating sub-models for the diesel engine and the lithium battery. Secondly, HEV acceleration performance under −20 °C was investigated, warm-up time of the diesel engine and battery reduced by 6.7 % and 4.1 %, respectively, using a genetic algorithm, which in turn decreased the time required for vehicle acceleration by 4.2 %. Finally, the economic performance of the HEV at −5 °C was investigated by comparing three adaptive equivalent consumption minimization strategies (ECMS). The A-ECMS-AW strategy exhibited the best performance, achieving a reduction in equivalent fuel consumption by 5.4 % compared to the A-ECMS-T and by 7.5 % compared to the A-ECMS.