Optimization Design Of Thermal Management System For Hybrid Powertrain

Hybrid Electric Vehicle(HEV)has been well developed in the automotive industry through continuous technological improvements since generation.However,due to the characteristics of multi-heat source,multi-temperature zone and variable temperature,it is more complex to control the HEV power train heat management system than that of traditional fuel vehicles and pure electric vehicles.Therefore,the optimization design and intelligent control of HEV power train heat management system have become one of the key technologies to further improve the vehicle power performance,economic performance and emission performance.In this paper,the optimal design of HEV power train heat management system is studied.Firstly,the heat production law of engine,motor and battery in hybrid power assembly is studied,including the engine one-dimensional combustion model is built in AVL-BOOST software and the heat production MAP diagrams of engine under different working conditions are obtained.According to the efficiency MAP diagrams of motor and motor controller under different working conditions,the corresponding heat production is obtained.According to D.Bernardi’s heat generation rate model,the heat production of battery under different working conditions is calculated,and so on.Secondly,according to the heat production law of each component of the HEV power train and the driving mode of the vehicle,with the thermal state of the components and the power consumption of the cooling system as the optimization targets,the innovative research of the thermal management system of the HEV power train is carried out,and the independent and the cooperative heat management system schemes and control strategy of the cooperative thermal management system are designed.The thermal management and power consumption requirements of engine,motor and battery are considered comprehensively.Then the HEV power train heat management system model and controller model are built and validated on the AMEsimSimulink joint simulation platform.Thirdly,under two continuous NEDC and FTP conditions,the cooling fluid outlet temperature of the power components is used to verify the cooling effect of the heat management system on the power components and the optimization of the total power consumption of the heat management system is studied.The simulation results show that the designed thermal management system not only ensures the engine and motor coolant outlet temperature in the optimal operating temperature range,but also reduces the power consumption of the thermal management system by 87.9% and 82.4% respectively.Finally,under the cooperative thermal management system,the FTP condition,the initial temperature is the ambient temperature and the cooling fluid outlet temperature of the engine and motor after the power assembly heat engine respectively.The driving mode of the vehicle is combined drive,the total power consumption of the engine and motor under different power distribution ratio K is studied and optimized.The simulation results show that when the initial temperature is ambient temperature,the difference of total power consumption is not significant when K < 3,but increases with K > 3.When the initial temperature is the temperature of the power component after the heat engine,the total power consumption first decreases and then increases with K increasing,and when K = 0.6,the total power consumption reaches the minimum.