| Fuel cell vehicle is a new energy vehicle with high efficiency,energy saving,pollution-free and low noise,which is one of the ideal directions for the future development of vehicle.However,the limitation of on-board energy is always a key factor restricting the development of new energy vehicles.As the auxiliary systems of new energy vehicles,electric air-conditioning system,electric brake and electric steering consume a lot of energy of the whole vehicle,especially the energy consumption of electric air-conditioning system accounts for about 33% of that of the whole vehicle,which seriously affects the endurance mileage of new energy vehicles.And as an essential auxiliary system in the process of vehicle driving,air-conditioning system directly affects the driving and riding comfort.In the existing fuel cell vehicles,the cab thermal management,fuel cell thermal management,power battery thermal management and motor thermal management were set up independently and managed separately,while the fuel cell vehicles did not coordinate and unify the integrated thermal management.As a result,the overall energy consumption of fuel cell vehicle thermal management was higher,and part of the thermal energy could not be reused.Therefore,this paper used the characteristics of high efficiency and energy saving of heat pump air-conditioning system as the core of heat cycle,integrated the cab temperature control,fuel cell system temperature control,power battery temperature control and motor temperature control of the whole vehicle,and designed an integrated vehicle heat management system.The system had a simple structure,which could take into account the driving comfort and unified the heat management of each system.The energy consumption of electric air-conditioning was reduced and the endurance mileage and energy utilization efficiency of new energy vehicles were improved through the heat recycling of the whole vehicle.Through the analysis of the principle and structure of heat pump air-conditioning,the energy efficiency comparison experiment between heat pump air-conditioning and water heating PTC air-conditioning was designed,and the characteristic of high energy efficiency of heat pump air-conditioning was verified;Based on the analysis of heat generation mechanism,heat transfer mechanism and temperature characteristics of fuel cell system and power battery system,as well as the thermal analysis of electrical system and electric motor,a vehicle integrated heat management system based on heat pump air-conditioning technology was designed,and relevant parameters were matched;Through AMESim software,the thermal management model of air-conditioning system,battery systems and motor electrical system were established,and the overall thermal management system model was completed;The whole vehicle control strategy based on logic threshold control strategy and the speed control strategy of electric compressor and water pump based on PID control were designed.And the feasibility and practicability of the thermal management system were simulated and analyzed based on SFTP-SC03 operation condition.The analysis results shown that the designed thermal management system can meet the temperature control of each system.And the energy consumption of the whole vehicle decreased by 6.1% and the endurance mileage increased by 5.6%.Finally,the feasibility of using the residual heat of the motor was analyzed,and it was found that the Joule heat flow of the motor is small,which was not enough to meet the heating requirements of the cab in winter,and coule be used as a heat supplement. |
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