Abstract
The key point of the research is to improve the eco-driving performance in a hybrid truck among various types of drivers. A car-following driver model with various drivers’ parameters is used in closed-loop vehicle-driver simulations to represent the driver’s longitudinal control behaviors in carfollowing situation. The regression analysis on the relationship between the driver parameters, driving performance and fuel economy shows how the driver parameters in longitudinal control affect the driving performance and the fuel economy. Then, a hybrid electric vehicle (HEV) controller consisting of an automatic gear controller and a hybrid torque distribution controller with a driving torque feedback compensator is designed. The automatic transmission controller calculates the optimal transmission gear ratio and the hybrid desired torque considering fuel economy. The hybrid torque distribution controller consists of two controllers: (1) a feedforward compensator selects the optimal torque distribution ratio for the engine and electric motor to ensure that the engine operates in the highest efficiency area and the total hybrid torque matches hybrid desired torque, (2) a feedback compensator of electric motor considering the torque response of hybrid system is designed by using the Model Matching Control method with a PID feedback compensator. By considering the torque response of hybrid system, it is expected that the feedback compensator improves the desired torque tracking performance and enhances the driving performance. Finally, the effectiveness of the system is verified by simulations. The simulation results indicate that by improving driving performance of the HEV, the proposed hybrid controller shows a potential in 12% improvement of fuel economy and also 9% reduction of fuel economy dispersion by different drivers in comparing with the conventional hybrid controller.
Keywords: Torque Distribution, Hybrid Truck /Vehicle Dynamics, Driver-Vehicle System, Closed-Loop System.