A real-time energy management strategy combining rule and optimization for minimizing energy consumption and emissions of flywheel hybrid electric vehicle (FHEV)

•DP algorithm is applied to obtain the optimal control of the FHEV.•Both energy consumption and emissions are considered for DP optimal control.•A solution to the DP that is difficult to be applied in real-time ECU is proposed.•The thermal efficiency of the ICE is significantly raised by 7.14%.•The fuel economy and emission performance of the FHEV are greatly improved. Planetary gear set based flywheel hybrid electric powertrain (PGS-FHEP) is regarded as one of the most promising approaches to improve vehicle performance owing to its advantages in load leveling, instantaneous power surge, and kinetic energy recovery. In this study, an energy management strategy (EMS) based on dynamic programming (DP) of the PGS-FHEP was proposed to further improve energy utilization and emission reduction. Then, to address the issue that the DP algorithm is difficult to apply in real-time, the decision rules were summarized from the results of the DP algorithm to improve the rule-based EMS (RB EMS). Finally, the improved RB EMS was simulated and verified under CLTC-C condition. The results showed that compared with the RB EMS, the average thermal efficiency of the internal combustion engine (ICE), motor/generator (MG) efficiency, and fuel economy under the improved RB EMS are increased by 7.14%, 3.6%, and 5.99%, respectively. For emissions, CO, HC, and NOX are decreased by 31.84%, 36.33%, and 49.41%, respectively. Besides, the higher energy storage flywheel (FW) speed helps to improve the instantaneous acceleration performance of the vehicle.