Abstract: Fit the instantaneous fuel consumption of engine to the piecewise function which is made up of a linear function and a quadratic function, fit the instantaneous equivalent fuel consumption of battery to the piecewise function which is made up of two quadratic function, Based on this, through the analysis of Hamilton function, the approximate pontryagin’s minimum principle real-time control strategy is proposed, which can shorten the optimization time by simplifying the optimal control variable search space, then compare this strategy’s optimization results of equivalent fuel consumption and computation time with the rule-based CD-CS mode control strategy and the optimal control strategy based on pontryagin’s minimum principle. The results show that: in terms of equivalent fuel consumption, optimization results of the real-time control strategy proposed are close to the optimal control strategy based on pontryagin’s minimum principle, but significantly better than rule-based CD-CS mode control strategy; in terms of computation time, the real-time control strategy is close to rule-based CD-CS mode control strategy, but significantly shorter than the optimal control strategy based on pontryagin’s minimum principle.

Key words: approximate pontryagin’s minimum principle, plug-in hybrid vehicle, pontryagin’s minimum principle, real-time control strategy