| Vehicle cabin, as an important tool for people having a middle or short distance travel,the environment of the compartment is receiving more and more attention. Air conditioning system, as a main method of environment regulation on bus has been the focus of research in the bus company.In this paper, three ways, observation, questionnaire survey and research environment numerical simulation were used on the basis of previous studies to learn the environment of the cabin. The temperature, velocity, relative humidity and the volume fraction of CO2 of four air-conditioned vehicle cabins were tested according to the standard specification of International Union of Railways UIC-533, bus heating ventilation and air conditioning, the size of air inlet was measured and the parameters of air supply was recorded. A subjective questionnaire was designed according to the international indoor air quality subjective survey method of universal which is suitable for long-distance passenger bus, and the questionnaire survey was conducted to the passengers in the cabin. The distribution of passengers’ subjective feelings on air quality inside the bus was obtained through the questionnaire survey.The grey relation method was used to analysis the correlation of measurement results and subjective investigation results, the main factors that affect the human comfort were found,and the corresponding improvement method was put forward.The method of simulation was used to verify the improvement effects. The pre CFD software was used to establish the 1:1 vehicle model, the mesh grid independent verification of the model was examined, the passengers were considered as constant heat flux heat sources,while the effects of solar radiation and heat conduction of the carriage were taken into account as constant heat flux heat source as the same. The reliability of model was verified through the comparative of analysis and experiment. The improved inner environment on the bus was evaluated from aspects of temperature, velocity, PMV, PPD and the average age of air, the evaluation results show that the improved bus air conditioning system meets the thermal comfort and air quality requirements of the passengers better. |
