城市公共汽车燃料经济性的影响因素

<正> 城市公共汽车是公交行业的主要生产工具,由于公交企业车辆数多,运行时间长,燃油消耗量大,其燃料的经济性严重地影响着公交企业的经济成本。分析城市公共汽车燃料经济性的影响因素,以最少的燃油消耗量完成运送更多乘客的工作量,这对提高公交企业的经济效益和社会效益都有着重要的意义。 城市公共汽车燃油消耗量是一个综合性的指标。它受诸多因素的影响,大体可概括为     

营运车辆燃料消耗量工况测试方法与质控技术研究

通过选用不同样车、采用不同仪器,从工况测试方法及车辆参数和仪器参数进行对比分析,得出仪器参数及车辆参数对于试验结果的影响。从而根据试验车辆确定仪器的选取,进一步验证试验方法,最后确定加速工况及怠速工况的测量方法。     

高原城市客车液化石油气燃料高原改造方案试验研究

文章基于对高原城市客车的液化石油气改造方案的研究,进行了改造车辆的道路试验研究分析。分析验证了改造方案的实际应用效果,证明了在车辆动力性降幅较小的情况下,使用该方案对城市客车进行的液化石油气改装,可以改善城市客车的排放。     

替代燃料的燃料消耗量计算方法

文章介绍了碳平衡原理的两个方面,燃烧和稀释前后的碳质量不变。介绍了完全燃烧后的CO2理论浓度和稀释倍数以及用稀释倍数校正稀释排气的方法,介绍了由碳质量分数推导替代燃料碳质量分数和当量分子式的方法,最后推导得出了可用于替代燃料的燃料消耗量计算公式。     

营运客车道路交通事故人因失误问题研究

<正>一、引言我国道路交通安全形势严峻,道路交通事故死亡人数占全世界的15%,多年高居世界第一。综观我国各种交通事故,客车肇事造成的交通事故最为突出。     

营运客车类型划分及等级评定工作的思考

对营运客车进行类型划分及等级评定(复核),是车辆技术管理的一项重要工作.阐述了营运客车类型划分及等级评定的基本要求,分析了营运客车类型划分及等级评定(复核)工作中存在的实际问题,指出各个部门应严格按交通部及运管部门有关文件和行业标准要求进行把关,进一步完善客运车辆的准入制度,推进营运客车技术进步和技术结构调整,确保道路客运事业健康发展.     

乘用车燃料消耗量标准推进中国节能与新能源汽车的发展

随着我国汽车保有量的不断攀升,环境污染和能源安全问题日益严重。节能减排势在必行,汽车作为国民经济的支柱产业责无旁贷。乘用车燃料消耗量第四阶段标准的颁布实施,将促使企业探索节能途径,促进我国汽车产业的转型升级,推进节能与新能源汽车产业的发展。     

不同驾驶操作方法下的汽车运行燃料消耗量分析

为了规范汽车驾驶节能操作,提高汽车行驶的经济性,本文按照汽车驾驶操作的流程,针对汽车起步、换挡变速、加减速、车速控制和变更车道等驾驶员普遍存在的驾驶节能操作认识误区开展研究,并利用实际道路试验和发动机台架试验进行燃料消耗量对比分析,总结了"轻踩缓抬"加速踏板、保持经济车速行驶、一脚离合配合换挡、避免"频繁变更车道、急加速和急减速"等驾驶节能操作方法。本文的研究将为广大驾驶员朋友和道路运输企业开展驾驶节能操作训练提供借鉴。     

不同驾驶操作方法下的汽车运行燃料消耗量分析

为了规范汽车驾驶操作,提高汽车行驶的经济性,本文按照汽车驾驶操作的流程,针对驾驶员普遍存在的驾驶节能操作认识误区,对汽车起步、换挡变速、加减速、车速控制和变更车道等驾驶操作开展研究,并利用实际道路试验和发动机台架试验进行燃料消耗量对比分析,总结了"轻踩缓抬"加速踏板、保持经济车速行驶、一脚离合配合换挡、避免"频繁变更车道、急加速和急减速"等驾驶节能操作方法。本文的研究将为广大驾驶员朋友和道路运输企业开展驾驶节能操作训练提供借鉴。     

Exhaust emissions and fuel consumption of a triple-fuel spark-ignition engine powered passenger car

This paper examines the influence of compressed natural gas, liquefied petroleum gas and gasoline fuel on the exhaust emissions and the fuel consumption of a spark-ignition engine powered passenger car. The vehicle was driven according to the urban driving cycle and extra urban driving cycle speed profiles with the warmed-up engine. Cause and effect based analysis reveals potential for using different fuels to reduce vehicle emission and deficiencies associated with particular fuels. The highest tank to wheel efficiency and the lowest CO₂ emission are observed with the natural gas fuelled vehicle, that also featured the highest total hydrocarbon emissions and high NO_x emissions because of fast three way catalytic converter aging due the use of the compressed natural gas. Retrofitted liquefied petroleum gas fuel supply systems feature the greatest air-fuel ratio variations that result in the lowest TtW efficiency and in the highest NO_x emissions of the liquefied gas fuelled vehicle.     

风帆助航对船舶主机油耗率的影响

加装风帆是船舶节能的有效途径,但风帆助航会影响船舶主机和其他系统的运行状况,对船舶能效的影响主要来自主机工况的改变。本文通过分析加装风帆后对螺旋桨工作特性的影响,推导出了计算主机油耗率的方法,并使用某超大型油轮(VLCC)的相关参数进行验证计算,证明此方法简单实用,可为计算风帆助航船舶能效指数EEOI等相关参数提供参考。     

The effect of uncertainty on US transport-related GHG emissions and fuel consumption out to 2050

The future of US transport energy requirements and emissions is uncertain. Transport policy research has explored a number of scenarios to better understand the future characteristics of US light-duty vehicles. Deterministic scenario analysis is, however, unable to identify the impact of uncertainty on the future US vehicle fleet emissions and energy use. Variables determining the future fleet emissions and fuel use are inherently uncertain and thus the shortfall in understanding the impact of uncertainty on the future of US transport needs to be addressed. This paper uses a stochastic technology and fleet assessment model to quantify the uncertainties in US vehicle fleet emissions and fuel use for a realistic yet ambitious pathway which results in about a 50% reduction in fleet GHG emissions in 2050. The results show the probability distribution of fleet emissions, fuel use, and energy consumption over time out to 2050. The expected value for the fleet fuel consumption is about 450 and 350 billion litres of gasoline equivalent with standard deviations of 40 and 80 in 2030 and 2050, respectively. The expected value for the fleet GHG emissions is about 1360 and 850 Mt CO₂ equivalent with standard deviation of 130 and 230 in 2030 and 2050 respectively. The parameters that are major contributors to variations in emissions and fuel consumption are also identified and ranked through the uncertainty analysis. It is further shown that these major contributors change over time, and include parameters such as: vehicle scrappage rate, annual growth of vehicle kilometres travelled in the near term, total vehicle sales, fuel economy of the dominant naturally-aspirated spark ignition vehicles, and percentage of gasoline displaced by cellulosic ethanol. The findings in this paper demonstrate the importance of taking uncertainties into consideration when choosing amongst alternative fuel and emissions reduction pathways, in the light of their possible consequences.     

Vehicle mass as a determinant of fuel consumption and secondary safety performance

One interaction between environmental and safety goals in transport is found within the vehicle fleet where fuel economy and secondary safety performance of individual vehicles impose conflicting requirements on vehicle mass from an individual’s perspective. Fleet characteristics influence the relationship between the environmental and safety outcomes of the fleet; the topic of this paper. Cross-sectional analysis of mass within the British fleet is used to estimate the partial effects of mass on the fuel consumption and secondary safety performance of vehicles. The results confirmed that fuel consumption increases as mass increases and is different for different combinations of fuel and transmission types. Additionally, increasing vehicle mass generally decreases the risk of injury to the driver of a given vehicle in the event of a crash. However, this relationship depends on the characteristics of the vehicle fleet, and in particular, is affected by changes in mass distribution within the fleet. We confirm that there is generally a trade-off in vehicle design between fuel economy and secondary safety performance imposed by mass. Cross-comparison of makes and models by model-specific effects reveal cases where this trade-off exists in other aspects of design. Although it is shown that mass imposes a trade-off in vehicle design between safety and fuel use, this does not necessarily mean that it imposes a trade-off between safety and environmental goals in the vehicle fleet as a whole because the secondary safety performance of a vehicle depends on both its own mass and the mass of the other vehicles with which it collides.     

Effects of driving style on the fuel consumption of city buses under different road conditions and vehicle masses

The variance in fuel consumption caused by driving style (DS) difference exceeds 10% and reaches a maximum of 20% under different road conditions, even for experienced bus drivers. To study the influence of DS on fuel consumption, a method for summarizing DS characteristic parameters on the basis of vehicle-engine combined model is proposed. With this method, the author proposes 26 DS characteristic parameters related to fuel consumption in the accelerating, normal running, and decelerating processes of vehicles. The influence of DS characteristic parameters on fuel consumption under different road conditions and vehicle masses is quantitatively analyzed on the basis of real driving data over 100,000 km. Analysis results show that the influence of DS characteristic parameters on fuel consumption changes with road condition and vehicle mass, with road condition serving a more important function. However, the DS characteristics in the accelerating process of vehicles are decisive for fuel consumption under different conditions. This study also calculates the minimum sample size necessary for analyzing the effect of DS characteristics on fuel consumption. The statistical analysis based on the real driving data over 2500 km can determine the influence of DS on fuel consumption under a given power-train configuration and road condition. The analysis results can be employed to evaluate the fuel consumption of drivers, as well as to guide the design of Driver Advisory System for Eco-driving directly.     

How much disruption to activities could fuel shortages cause? – The British fuel crisis of September 2000

In September of 2000 the UK experienced a blockade of oil refineries in response to rising fuel prices. These protests resulted in severe fuel supply disruptions that intensified over the course of about one week. During the peak of the crisis, travel activity by car was curtailed. This paper analyzes survey data collected about two months after the crisis utilizing the recent memory of respondents as to how they would expect this sort of disruption to affect their participation in daily activities. Specifically, we focused on a variety of non-discretionary and discretionary activities and examined what factors are associated with respondents expecting disruption to those activities. Statistical models were developed to analyze how demographic factors, commute mode selection, vehicle characteristics, and various other factors can explain how individuals expect disruption to their activities. Results suggest that the majority of individuals do not expect major disruptions, although for more car-dependent individuals, disruption was expected to be substantial, especially for work-related trips. These results have implications for the potential success and benefits of an integrated transport policy.     

The design of a terminal for dangerous goods

This paper aims at examining the possibility of setting up a model terminal for the transportation of dangerous goods. It should be designed in such a manner that its use would be possible for any kind of transportation.

This consideration has been prompted by the interface between transportation planning and technology, as well as by the tendency for harmonizing international recommendations pertaining to the transportation and handling of dangerous goods, especially during the last decades where unified transport has gained ground due to the advantages provided for the safe consignment of dangerous cargoes.

Since the large increase in terminal productivity is due to the heavy investments that were effected in terminal installations and to the modernization of the administration‐management of terminals, a mathematical simulation has been adopted to assist the determination of the capacity of a terminal for dangerous goods.

It is evident that different criteria and various assumptions have been taken into account in order to facilitate a deeper analysis, without ignoring the contribution of dangerous goods to the socio‐economic development.

From the outset of the study, it was already clear that the said process will make it possible to present—as a model—a simple but well defined situation for the purpose of drawing useful conclusions.     

The impact of fuel availability on demand for alternative-fuel vehicles

We study the impact of fuel availability on demand for alternative-fuel vehicles, using data from a survey of potential car buyers in Germany. The survey was conducted as a computer-assisted personal interview and included a choice experiment involving cars with various fuel types. Applying a standard logit model, we show that alternative fuel availability influences choices positively, but its marginal utility diminishes with supply. Furthermore, we derive consumers’ marginal willingness-to-pay for an expanded service station network. The results suggest that a failure to expand the availability of alternative fuel stations represents a significant barrier to the widespread adoption of alternative-fuel vehicles.     

Improving the forecasting accuracy of air passenger and air cargo demand: the application of back-propagation neural networks

This study employs back-propagation neural networks (BPN) to improve the forecasting accuracy of air passenger and air cargo demand from Japan to Taiwan. The factors which influence air passenger and air cargo demand are identified, evaluated and analysed in detail. The results reveal that some factors influence both passenger and cargo demand, and the others only one of them. The forecasting accuracy of air passenger and air cargo demand has been improved efficiently by the proposed procedure to evaluate input variables. The established model improves dramatically the forecasting accuracy of air passenger demand with an extremely low mean absolute percentage error (MAPE) of 0.34% and 7.74% for air cargo demand.     

Analysis of factors affecting the choice of route of pedestrians

Pedestrians as compared to vehicular traffic enjoy a high degree freedom of movement even in heavily congested areas. Consequently, there are more alternative links available to pedestrians between a given origin‐destination (O‐D) pair. This paper describes a study done by the University of Calgary to evaluate the factors affecting the choice of route on intra‐CBD trips or trips within the Central Business District (CBD).

An origin destination survey conducted in downtown Calgary, Alberta enabled the identification of the most significant factors influencing the choice. These factors were analyzed in relation to the physical characteristics of the location, personal characteristics of the trip maker and the type of the trip.

It appears that most people chose the shortest link and factors such as the level of congestion, safety or visual attractions were only secondary. This suggests that the length should be made a major consideration when planning and designing pedestrian links.