Abstract:

Energy flow analysis is a crucial tool for enhancing vehicle efficiency and optimizing hybrid electric vehicle (HEV) control strategies. This study conducted an energy flow experiment on a series-parallel HEV to address high fuel consumption. GT-Suite and MATLAB/Simulink co-simulation models were built and calibrated to address the problems of the original HEV control strategy. Two optimized vehicle control strategies (Opt1 and Opt2) were tested to test fuel savings. The optimized strategies included canceling series and parallel charging in the braking state, adding engine direct-drive mode, and reducing the proportion of parallel mode. The simulated results showed that the 100 km fuel consumptions of Opt1 and Opt2 were reduced by 7.1% and 7.5% compared to the original vehicle. The proportion of energy driving the vehicle directly through the engines increased from 45.7% to 70.2% and 61.6%, respectively. The total vehicle energy losses decreased from 29.0% to 22.5% and 22.9%. Despite the high thermal efficiency of the original vehicle's engine, the entire powertrain system's efficiency was the lowest, resulting in the highest fuel consumption.