Research On Energy Saving And Thermal Comfort Integrated Control Of Automobile Air Conditioning

In recent years China’s auto industry has developed rapidly,but the following problems of have gradually emerged.This paper aimed to enhance the comprehensive effect of automobile air conditioning system thermal comfort and vehicle energy saving and emission reduction as the target of research.This paper first introduces the basic structure and operation principle of the automobile air conditioning system.The number of passengers based on CATIA three-dimensional control equations describing the flow field of Physics(mass equation,momentum equation and energy equation),the establishment of boundary conditions,meshing with a discrete equation RNG equation and DO K-epsilon two radiation equation,determine the convergence of discrete equations determined after the results of CFD numerical simulation can be applied to engineering practice.The establishment of air conditioning system includes an evaporator,condenser and compressor and other components in MATLAB,through the numerical simulation of the steady in medium and high speed,idling conditions calculated head and waist monitoring point temperature is the temperature too small a maximum error of 1 Deg.C,show that the system model can be applied to the engineering practice,validation the feasibility of the model.Finally,the numerical simulation results are applied to the air conditioning system model,which establishes the theoretical basis for the follow-up control strategy.According to the technical requirement of the whole vehicle control target,the comfort evaluation index describing the overall thermal perception deviation of the human body and the calculation method of the energy saving evaluation index describing the conversion ratio between energy and heat are given.By controlling the opening and stopping of the compressor and the opening of the mixed air door,the evaluation index can be affected,and the two main control objects of the paper are locked.The principle of compressor participating in the system operation isstudied.The starting and stopping state of compressor is controlled by variable threshold temperature.As a result,the heating condition of the air after evaporator is prevented as much as possible,and the energy saving effect is achieved.According to the characteristics of temperature control system in air conditioner,the temperature system is controlled by PID.The input of PID is the room temperature deviation,and the output is the opening size of the mixed throttle.The parameters of PID are optimized as follows: KP= 4.2;KI= 0.3;KD= 1.1.According to the control target,the control strategy of thermal comfort of human body is put forward.Finally,in the passenger cabin thermal comfort and energy saving optimization index as the research object,put forward a will consider joining the comfort index PID principle to enhance the comfort and variable threshold temperature control of the compressor start and stop in order to achieve the multi-objective control methods of energy conservation.In the passenger compartment,12 representative monitoring points,such as head and chest,are selected to monitor the changes of temperature field in the calculation area.In the idle,medium speed and high-speed conditions,the temperature field simulation of the driver’s surface was carried out on the front instrument panel and the passenger compartment section.The results of real-time monitoring and simulation are compared and analyzed.The results show that the thermal comfort of the human body is closer to the ideal comfort index,and the utilization rate of the energy efficiency index COP of the air conditioner is basically higher than that of the optimized 1.The validity of the control method is proved.In this paper,the whole vehicle energy saving and the thermal comfort of passenger cabin are comprehensively controlled,and the optimal equilibrium point of the two is obtained by using particle swarm optimization.It has a certain market application prospect.Limited by the computational power,the human model used in this paper is relatively simple,but now some scholars have studied and put forward a three-dimensional mathematical model which can accurately describe the physiological thermal response characteristics of human body.The study of human physiological mathematical model coupled with CFD will describe the thermalsensation comfort of human body more accurately,and is one of the future directions.