Energy Management Strategy of Hydraulic Hybrid Vehicles Based on Instantaneous Equivalent Fuel Consumption Minimization

Abstract

In order to improve the fuel economy and reduce the emissions of hybrid vehicles, according to the power flow distribution and energy use in hybrid vehicles, the strategy of the minimization of instantaneous equivalent fuel consumption was put forward. Based on analyzing the relationship between power transmission and energy flow in a series hydraulic hybrid, and taking the virtual equivalent fuel consumption of an energy storage element accumulator as a criterion, the model of the minimization of transient equivalent fuel consumption in hydraulic hybrid vehicles was established. Energy management for such vehicles is also discussed. The parameters of a bus are taken as examples in simulating the fuel economy of hydraulic hybrid vehicles. In the simulation, the developed strategy is applied to the initial periods of the urban driving and highway driving cycles. Results show that (1) the proposed strategy achieves a 30% improvement rate for the fuel economy of hydraulic hybrid vehicles, and that (2) minimizing instantaneous equivalent fuel consumption presents remarkable advantages in improving energy conservation in vehicles.