Research On Temperature And Humidity's Control And Simulation Of Automobile Passenger Compartment

Because automobile air-condition is of pyrology system, the control strategy of cabintemperature and humidity was mainly bang-bang control in the past years. With the rapidcompetition of auto market and high demands for comfort, PID and fuzzy control method isinstead of bang-bang control recently. Research on temperature and humidity includesexperiments and simulation, that if the accurate simulation is introduced into the research oftemperature and humidity, researching time will be reduced with the reduction of repeatedexperiments.After analyzing the principle and structure of automobile air conditioner, it is known thattemperature and humidity of compartment is primary factor which influence thermal comfort ofautomobile passenger compartment, that temperature is more important.The temperature of cabin is mainly affected by heat load and thermal changing by A/Csystem. That heat load of cabin is including solar load, conductive load, passenger load andheat load brought by new air, A/C thermal changing is associated with speed of air andcoefficient of heating exchanging with evaporator and heater. In the dissertation, fuzzycontrollers for fan's speed, mixing damper, compressor switching and heater switching whoseinputs is all eT (error of temperature) and ecT(rate of eT) are designed for cabin temperature.Simulations show that fuzzy control is superior than bang-bang control and PID Control thatcontinually on-off and bad dynamic performance. Meanwhile variable-universe adaptivefuzzy controller is introduced for improving steady performance and dynamic performance.EEV (electrical expansion valve) is replacing TEV (thermal expansion valve) to regulatethe flow rate of the refrigerant, which would influence the superheat of evaporator. A kind ofgeneral fuzzy controller for superheat is designed in the thesis, it turns out that simulationresult is good.Considering that automobile A/C system control humidity using the influence bytemperature instead of adding humidity method. Fuzzy logic controller which includingprimary parameter eT and improving parameter eH (error of humidity) is designed for controlling humidity. In the simulation model, the modular of according to a series ofASHRAE formula.