Factors contributing to ventilation quantity of the vehicle are ventilation modes, cabin characteristics and vehicle speeds. CO2 levels were investigated under different speeds and ventilation modes. Four modes were s...Factors contributing to ventilation quantity of the vehicle are ventilation modes, cabin characteristics and vehicle speeds. CO2 levels were investigated under different speeds and ventilation modes. Four modes were selected： A： vent closed and fan shut, B： vent closed and fan started, C： vent opened and fan shut, D： vent opened and fan started. In vent closed modes, CO2 levels reached several thousands of ppm in few minutes at any speeds. For mode C, CO2 levels exceeded the guideline at low speeds 50 km/h, while it reduced below one at higher speeds 80 km/h. Fan has no significant impact on ventilation during vent closed. The ventilation efficiency in each mode increased with the speed raising. To determine the ventilation rate of running vehicle, the experiment was implemented by using CO2 emitted from driver and passengers as tracer gas. Ventilation rate for the different modes and speeds were calculated.展开更多
Based on the Nagel-Schreckenberg model, we propose a new cellular automata model to simulate the urban rail traffic flow under moving block system and present a new minimum instantaneous distance formula under pure mo...Based on the Nagel-Schreckenberg model, we propose a new cellular automata model to simulate the urban rail traffic flow under moving block system and present a new minimum instantaneous distance formula under pure moving block. We also analyze the characteristics of the urban rail traffic flow under the influence of train density, station dwell times, the length of train, and the train velocity. Train delays can be decreased effectively through flexible departure intervals according to the preceding train type before its departure. The results demonstrate that a suitable adjustment of the current train velocity based on the following train velocity can greatly shorten the minimum departure intervals and then increase the capacity of rail transit.展开更多
文摘Factors contributing to ventilation quantity of the vehicle are ventilation modes, cabin characteristics and vehicle speeds. CO2 levels were investigated under different speeds and ventilation modes. Four modes were selected： A： vent closed and fan shut, B： vent closed and fan started, C： vent opened and fan shut, D： vent opened and fan started. In vent closed modes, CO2 levels reached several thousands of ppm in few minutes at any speeds. For mode C, CO2 levels exceeded the guideline at low speeds 50 km/h, while it reduced below one at higher speeds 80 km/h. Fan has no significant impact on ventilation during vent closed. The ventilation efficiency in each mode increased with the speed raising. To determine the ventilation rate of running vehicle, the experiment was implemented by using CO2 emitted from driver and passengers as tracer gas. Ventilation rate for the different modes and speeds were calculated.
基金Supported by the National Basic Research Program of China under Grant No. 2012CB725400the National Natural Science Foundation of China under Grant No. 71131001-1the Research Foundation of State Key Laboratory of Rail Traffic Control and Safety under Grant No. RCS2011ZZ003, Beijing Jiaotong University
文摘Based on the Nagel-Schreckenberg model, we propose a new cellular automata model to simulate the urban rail traffic flow under moving block system and present a new minimum instantaneous distance formula under pure moving block. We also analyze the characteristics of the urban rail traffic flow under the influence of train density, station dwell times, the length of train, and the train velocity. Train delays can be decreased effectively through flexible departure intervals according to the preceding train type before its departure. The results demonstrate that a suitable adjustment of the current train velocity based on the following train velocity can greatly shorten the minimum departure intervals and then increase the capacity of rail transit.
