Thermal Comfort Evaluation Of Vehicle Passenger Compartment Based On The Subjective And Objective Test

As an important part of vehicle comfort,more and more researchers have been draw attention to the thermal comfort of the passenger compartments.Understanding the thermal response status of the passenger to the thermal environment in the passenger compartment,and establishing a thermal sensation prediction model can help us explore the impact of the thermal environment on the thermal response status of the passenger,to design and optimize the thermal environment in the passenger compartment.The study analyzes the thermal environment distribution,passengers’thermal sensation,and thermal comfort with the subjective and objective tests results of the passengers’thermal comfort in a car.The thermal comfort evaluation prediction models for the passenger compartment are established based on the SVM method,and then the evaluation accuracy of the models are verified.The main contents and results of the study are:(1)The subjective and objective tests of the occupants’thermal comfort in a vehicle.The environment parameters are tested in the heating conditions and the cooling conditions.Tested,recorded,and digitized the subjective feelings of the occupants in the car based on the ASHRAE seven-point scale.The research results show that the distribution of the thermal environment inside the car is transient and uneven in the horizontal and vertical directions.And there are obvious differences in the occupants’local thermal sensation of the various body positions,and the local thermal sensation has a nearly linear relationship with the air temperature.There is relationship between thermal sensation and thermal comfort,but it is different from the cognition of the existing human thermal comfort judgment method.(2)Comparative analysis of the applicability of two existing thermal comfort evaluation models.The existing thermal comfort evaluation models are used to evaluate the thermal comfort of occupants under test conditions.Then the evaluation results are compared with subjective scoring results.For the non-extreme thermal environments such as the climate in March of the Southwest region,the PMV-PPD evaluation model can be used to predict the local thermal sensation of the human body.But the PMV-PPD evaluation model can’t apply to the extreme environments.What’s more,the EQT evaluation index can qualitatively predict the change in the thermal sensation of the occupants,but the accuracy of the EQT evaluation results is not ideal.(3)Established SVM thermal comfort evaluation model for automobile passenger compartment.Based on the experimental results,the thermal environment inside the car and thermal comfort of passengers are analyzed.Then,the support vector machine method is used to build the prediction models for the evaluation of the passenger’s thermal comfort based on the test results.And the thermal comfort evaluation models are verified.The MSE of the local sensation evaluation prediction model is less than0.01,and R~2 is more than 0.7.The prediction accuracy of the overall thermal sensation and comfort evaluation model is greater than 70%.The SVM evaluation models can effectively predict the thermal comfort of occupants in a car.(4)The thermal performance of occupants in different external thermal environments is analyzed,and the seasonal classification model is established.There are different thermal preferences for occupants in different natural environments.And the tolerance of the human body to the surrounding air temperature is very different in different seasons.Based on the temperature and humidity of the black ball radiation in the car,the SVM seasonal classification thermal comfort model is established,which can more conveniently evaluate the thermal comfort of the passenger cabin in different seasons.