Understanding the impacts of a combination of service improvement strategies on bus running time and passenger’s perception

Transit agencies implement many strategies in order to provide an attractive transportation service. This article aims to evaluate the impacts of implementing a combination of strategies, designed to improve the bus transit service, on running time and passenger satisfaction. These strategies include using smart card fare collection, introducing limited-stop bus service, implementing reserved bus lanes, using articulated buses, and implementing transit signal priority (TSP). This study uses stop-level data collected from the Société de transport de Montréal (STM)’s automatic vehicle location (AVL) and automatic passenger count (APC) systems, in Montréal, Canada. The combination of these strategies has lead to a 10.5% decline in running time along the limited stop service compared to the regular service. The regular route running time has increased by 1% on average compared to the initial time period. The study also shows that riders are generally satisfied with the service improvements. They tend to overestimate the savings associated with the implementation of this combination of strategies by 3.5-6.0 min and by 2.5-4.1 min for both the regular route and the limited stop service, respectively. This study helps transit planners and policy makers to better understand the effects of implementing a combination of strategies to improve running time and passenger’s perception of these changes in service.     

An operational activity-based method to estimate CO2 emissions from container shipping considering empty container repositioning

This paper develops an operational activity-based method to estimate CO₂ emissions from container shipping in contrasts to the traditional aggregated activity-based method. Two case studies investigate the impacts of empty container repositioning policies and port handling capacity on CO₂ emission index. The results show that the aggregated method could well overestimate CO₂ emissions and the operational activity-based method is more appropriate. The paper also demonstrates that high port-handling capacity and efficient empty container repositioning could reduce CO₂ emissions in seaborne container transportation.     

中压直流综合电力系统燃油经济性调度策略

由于研究对象、运行要求和调控手段存在差异,陆用电力系统和传统船用电力系统的燃油经济性策略无法直接应用到中压直流综合电力系统中。针对中压直流综合电力系统的能量优化调控需求,建立综合电力系统燃油经济性调度模型,提出基于分层优化方法的系统燃油经济性调度优化算法,实现对整流发电机组出力的优化。同时,提出适用于中压直流综合电力系统燃油经济性优化调度的方法,实现对发电机出力的优化调度,并通过仿真试验验证该方法的有效性。     

The Alternative Motor Fuels Act, alternative-fuel vehicles, and greenhouse gas emissions

The corporate average fuel economy (CAFE) standard is the major policy tool to improve the fleet average miles per gallon of automobile manufacturers in the US. The Alternative Motor Fuels Act (AMFA) provides special treatment in calculating the fuel economy of alternative-fuel vehicles to give manufacturers CAFE incentives to produce more alternative-fuel vehicles. AMFA has as its goals an increase in the production of alternative-fuel vehicles and a decrease in gasoline consumption and greenhouse gas emissions. This paper examines theoretically the effects of the program set up under AMFA. It finds that, under some conditions, this program may actually increase the production of fuel-inefficient gasoline vehicles, gasoline consumption and greenhouse gas emissions.     

燃料电池气体温湿度与电堆性能分析

系统性能指标是实现燃料电池工程化应用的瓶颈之一,系统搭建和调试过程中,空气与燃料温湿度是影响质子交换膜燃料电池性能的重要因素,对系统控制策略和辅机搭配方案的制定产生很大影响。本文通过实验与统计相结合的研究方式,研究15 kW燃料电池电堆在增湿温度分别为60℃、70℃和80℃条件下分别进行氢空单侧增湿、双侧增湿和不增湿时的输出功率、发电效率和单电池电压一致性。其中输出功率采用测试台直接测量、发电效率通过经验公式计算、电压一致性则通过巡检记录和统计方法相结合的方式评价。结果表明70℃时各增湿方案下优于其他温度同等湿度条件下的电堆性能,有增湿条件明显优于无增湿方案电堆性能,而双侧增湿和氢空单侧增湿对电堆性能影响不大。     

船舶绿色电源PEMFC及其性能影响因素分析

能源与环境制约了各国经济的持续发展,绿色船舶成为当前船舶行业的发展趋势,燃料电池作为绿色电源在船舶行业具有广阔的应用前景。燃料电池是一种多输入的电化学反应装置,影响因素较多。该文在验证了质子交换膜燃料电池(Proton Exchange Membrane Fuel Cells,PEMFC)稳态建模正确性的基础上,通过稳态建模,利用MATLAB对影响PEMFC性能的各因素进行了分析讨论,并给出了各影响因素的影响大小。最后,在PEMFC的控制和设计上提出了一些指导性的建议。     

发电机组并联运行有功、无功综合调控技术

介绍了发电机组的转速、电压控制原理以及有功、无功综合调控技术的控制原理;并通过实例介绍了采用该控制技术的船舶电站监控系统。实践表明,融合有功、无功综合调控技术的电站监控系统在投入运行后,实现了任意组态下,并联机组有功、无功功率稳定的自动调整,使得多个电站机组长期并联运行更加可靠。     

城市客车内饰风道设计简述

城市客车内饰风道设计的好坏对车辆的运行性能似乎没有什么影响,往往容易被忽视。风道不仅影响到内饰的美观而且对空调客车内室的保温、减少空调系统的损失,提高运行经济性起到至关重要的作用。这里对城市客车风道的结构设计、材料应用及其隔热措施保温提出了自己的见解,并着重叙述了风道的保温。     

中型客车企业工业污水处理工艺探讨

现代客车整车生产企业在生产中的工业用水主要是车身表面涂前处理废水、打磨废水、油漆处理所产生的油漆废水,常规处理方法是先预处理、再生化处理,难度大,成本高。本公司采用系统分析,分项处理,合理回收利用的新型污水处理工艺。     

混合动力汽车通信网络研究

阐述CAN规范和SAE J1939协议;SAE J1939是适用于货车和客车的应用层协议,对于混合动力汽车却没有统一的应用层协议。本文参照SAE J1939协议格式制定出适用于混合动力汽车(HEV)的应用层协议;结合混合动力汽车的控制特点,提出了CAN总线和LIN总线并用的双总线控制方法;通过实验测试了混合动力汽车CAN总线通信性能。实验结果表明,通信网络性能满足控制的实时性要求。