A study on the control rule for driving charging in a parallel hybrid electric bus

With a parallel ISG hybrid electric bus as object, two existing optimal control algorithms for system efficiency are compared, and a revised algorithm is proposed. Based on these three algorithms the corresponding driving charging mode switching rules and torque distribution rules are determined respectively with comparative simulation and hardware-in-the-loop verification test conducted. The results indicate that the proposed driving charging control rule for optimal system efficiency further enhances vehicle energy economy. With the rule, when engine works in low-efficiency condition, driving charging performs with reasonable electricity generation in a relatively high efficient way. As a result, the secondary conversion of a large amount of energy is avoided, while the energy saving is achieved through replacing the low-efficient work of engine by motor drive. The energy economy of vehicle with the proposed control rule is 13% and 20% higher than that with two other control rules, verifying the rationality of the proposed control rule and providing references for the research and application of optimal control algorithm for system efficiency. ©, 2015, SAE-China. All right reserved.