| With the booming development of the New Energy Vehicles（NEVs）industry,the endurance mileage of pure electric vehicles has gradually come into public view.Since the air conditioning system is the main energy consumer of a whole vehicle,reducing its load has become a very important means to ensure a longer endurance mileage for the vehicle.At the same time,the research of smart cockpit by major car companies is also gradually deepening.According to people’s needs,actively adjusting and unconsciously improving the comfort performance of human body has become a major development direction of smart cockpit.As thermal comfort is a very important part of ergonomics,how to regulate it in the smart cockpit has become the focus of attention of all parties.There are many factors affecting passengers’thermal comfort inside and outside the car,and improper ventilation conditions often fail to meet the thermal comfort standard and consume a considerable amount of energy.Therefore,this thesis has investigated the influence of different ventilation parameters and the parameters in the external environment on the thermal environment in the passenger compartment,in order to find suitable energy-saving optimization measures for air conditioning system.Follow the idea of industrial design engineering,solve the harmonious relationship between people and vehicles,and finally achieve the multi-objective optimization of reducing the heating load of automobile air-conditioning system while improving the thermal comfort of passengers.Based on the thermal comfort performance development project of an SUV model,a physical simulation model of the internal and external flow field of the whole vehicle,as well as a Fiala three-dimensional human thermo-physiological model has been built.And the simulation model is verified and optimized through the external vehicle sunshine experiments.Based on the simulation model,the effects of three ventilation parameters,namely air velocity,air temperature,and air humidity,on the internal environment of the passenger compartment under extreme summer heat have been investigated respectively,their affecting pattern on the driver’s thermal comfort and the heating load of air-conditioning system further explored,and a multi-parameter regression equation fitting conducted to propose an optimized ventilation scheme for the specific external environment in this research.After verification under the same external environmental conditions,the model has successfully achieved a reduction in air conditioning system load with an improved thermal comfort.At present,the thermal comfort development of automobiles usually only uses the interior Concept A Surface（CAS）model of passenger compartment,and simulates the external environment by setting a fixed wall temperature and solar radiation intensity.However,the external environment of the actual car is changing all the time.To realize real-time control of different external environmental conditions in the smart cockpit,it is inseparable from its accurate simulation.In order to improve the accuracy of the simulation development process of automobile thermal comfort,this thesis has also conducted a simulation analysis of the three external environmental parameters that exert significant effects on the internal environment of the passenger compartment,namely,solar radiation intensity,external temperature,and vehicle driving speed,by using a simultaneous operation of both the internal and external flow field and explored the effects of the three parameters on the internal and external thermal environment of the passenger compartment as well as on thermal comfort and load.Under extreme summer heat currently considered,solar radiation intensity has the most significant influence on the thermal environment inside the passenger compartment and passengers’overall thermal comfort,while external temperature only exerted a relatively minor influence and vehicle driving speed the most minor one.However,for the air conditioning system load,all three external environmental parameters are equally important influencing factors that cannot be ignored.This thesis has fitted respectively the various relationships between passengers’overall thermal comfort Coverall and air velocity v under typical solar radiation intensity,external temperature,and driving speed,and also established a regression equation,the result of which has been obtained.Through verification,the load of air conditioning system has been significantly reduced with the thermal comfort target achieved for the designed external environment conditions,and the balance between people and car is realized.In this thesis,the feasibility of simultaneously building an internal and an external flow field to analyze the effects of various conditions on the internal thermal environment of the passenger compartment has been investigated.On this basis,by using the cloud images of the flow field inside and outside the vehicle and the calculation results of each evaluation index,studying the influence rules of various influencing factors on the heating load and thermal comfort,and finally achieved the multi-objective optimization of reducing the heating load of automobile air-conditioning system while improving the thermal comfort of passengers.Based on the relevant knowledge of ergonomics,environmental science,automotive aerodynamics and other disciplines,and combining theory with practice.The results of this thesis can serve as a theoretical basis for the subsequent optimization of passengers’thermal comfort or air conditioning energy consumption that will be conducted at the level of air supply parameters,and also as a reference value for the design of automatic air conditioning system of automobile smart cockpit products in the future. |
