Abstract: Aiming at the problem that the optimum equivalent factor relies heavily on the driving cycle in the equiva- lent consumption minimization strategy (ECMS),by taking a single-axis parallel hybrid electric vehicle as the re- search object and based on the optimal control results obtained through the dynamic programming (DP) in a special driving cycle,an instantaneous optimal equivalent factor in the framework of the ECMS is obtained in a reverse way.Then,the change rules of the average optimal equivalent factor with the charge-sustaining level are fitted.On this basis,an adaptive equivalent consumption minimization strategy is designed.The simulation results of a typical urban driving cycle in China show that,for an arbitrary initial SOC,the designed strategy can stabilize the battery capacity in a fixed value,and that the fuel consumption is 828g after stabilizing the SOC,which indicates an error of only 0. 8% in comparison with that obtained through the DP.The simulation results of other kinds of driving cy- cles show that the change rules of the SOC in the other cycles accord well with those in the typical urban driving cy- cle,and after stabilizing the SOC,the fuel consumption increases only by 0. 1% ～0. 2% in comparison with that obtained through the DP in a single cycle.

Key words: hybrid vehicles, equivalent consumption minimization strategy, dynamic programming, charge-sus- taining level