国产客车高速行驶中存在的主要问题及对策

中国正迎来高速公路运输的新时代。本文在大量统计调研的基础上,指出了国产客车高速行驶中存在的主要问题,并提出了相应的对策,为开发适应高速化的新产品和改进现有产品的性能提供了依据。     

高级公路的发展对客车性能的改进要求

随着我国高等级和高速公路的迅速发展，为客车行驶提供了良好的行驶条件，大大提高了客车运输的经济效益。但是，高速行驶也对客车在轮胎、制动性能、动力性能、空气动力性能和安全性能等方面暴露出的问题，提出改进提高措施。     

必须尽快开发我国高速公路客车专用底盘

公路高速客运是我国近年来出现的一种公路快速直达客运，它需要高性能的客车，而我国现生产的客车底盘基本上不能满足制造这种客车的要求。本文从高速公路的行车特点出发，分析了公路高速客运对客车底盘的要求和国产客车底盘技术性能与国外先进水平的差距；提出了开发高速公路客车专用底盘的近、远期目标。     

国产在用客、货汽车高速运行工况统计模型

通过大量的统计数据分析，获得了国产在用客、货汽车高速运行工况的统计模型及其分布参数估计值，为开发适应高速运输需要的客、货汽车及在用客、货汽车的性能(动力性匹配、空气动力性能、操纵稳定性及行驶平顺性能等)改进提供了理论依据。     

电涡流缓行器，为道路运输保驾护航

随着我国交通事业的发展，尤其是改革开放以来高速公路的迅猛发展，汽车高速行驶时的安全性变得尤为重要。在大中型客车和货车上安装电涡流缓行器是解决汽车高速行驶时安全性重要措施之一。     

客车配套电器质量调查与建议

调查表明,我国客车配套电器的故障率约占整车故障率的25%,若在高速公路上行驶,则电器故障率接近整车故障率的50%,电器产品的质量问题已经严重影响国产客车的质量和信誉。本文将列举几种主要电器产品的质量问题,分析产生这些问题的主要原因,以便于有关部门及生产厂采取措施,加以有效的改进。一、客车配套电器产品质量问题的主     

国产客车的正确选购与注意事项

当前,我国国民经济持续发展,高速公路建设一日千里,道路条件不断改善,城市化进程日益加快,旅游业蓬勃兴起,这些都进一步扩大了对客车的需求。据交通部门预测,近几年每年国产客车产销量均在8万辆左右。国有、集体、个体客运企业和客运业户,是国产客车的主要用户。客户在选购客车     

电涡流缓速器深受驾驶员欢迎

随着我国交通事业的发展,尤其是改革开放以来高速公路的迅猛发展,汽车高速行驶时的安全性变得尤为重要。在大中型以上客车和货车上安装电涡流缓速器是解决汽车高速行驶时安全性重要措施之一。我国大规模引进西班牙电涡流缓速器已有十几年的历史,技术上已经成熟并在不断发展,已普遍被用户所接受,可以说凡是使用过电涡流缓速器的驾驶员都赞不绝口。目前我国已将安装缓速器纳入了国家标准,势必为提高汽车行驶安全性发挥重要作用。     

国产子午线胎的标记含义

据资料统计,在全国高速公路上发生的交通事故中有40％以上是爆胎引起的,爆胎多为胎壁厚、散热慢、不适宜高速行驶的普通斜交胎。子午线胎胎壁薄、胎面耐磨、胎体生热慢,是高速公路上高速行车的必然选择。 国产双钱牌载重汽车用子午线胎的速度等级分别为L、M、N3个等级,其最高限速分别为120、130、140km/h;回力牌轿车子午线胎的速度等级分别为S、T、H3个等级,其最高限速分别为180、190、210km/h。     

客车前风挡玻璃粘接力计算分析

随着客车技术的渐渐成熟,人们对客车的安全系数有了越来越高的要求。尤其对于在公路上高速行驶的客车来说,安全因素是考虑的首要因素。以下针对客车前风挡玻璃在高速行驶,紧急制动情况下受力状态加以阐明。     

基于比功率参数的北京市柴油公交车行驶和排放特征研究

利用车载尾气检测设备和GPS系统收集了北京市重型柴油公交车实际行驶和排放数据,引入汽车比功率(VSP)参数,建立柴油公交车排放预测方法,并对柴油公交车的实际运行和排放特征进行了分析.行驶特征分析表明,公交车在北京市五环内的平均速度为17.17km/h,其80%以上行驶处于VSP区间[-1,3]kW/t;排放特征分析表明,柴油公交车瞬时高排放集中在VSP≥lOkW/t区间,表明高加速或快速行驶是引起瞬时高排放的主要原因.     

北京市公共汽车平均车速统计分析

通过对北京市多条公共交通路线公共汽车行驶车速的实测和统计，分析了公共汽车平均车速的影响因素，研究了平均车速的三种统计计算方法，确立加权平均车速法为最佳统计计算方法。对北京市公共汽车平均车速的在不同类型道路上分布的情况和统计分布规律进行了总结，提出北京市公共汽车平均车速分布遵循对数正态概率分布规律。为公共汽车及今后电动公共汽车车辆选型，运营方式确定及运营成本分析提供了科学依据。     

北京城市公交客车循环工况开发

详细地论述了城市客车循环工况开发的程序和测试方法,并通过自行设计的测试仪器和数据采集系统,完成了北京城市客车循环工况的测量。详细分析了北京公交客车的实际运行特点,得出了北京城市客车的平均车速、运行时间、停车时间、加减速度以及客流量服从正态分布。同时,分析了变速器挡位分布。基于城市工况的特征,提出了一种多条线路循环工况的合成方法。结果表明,所开发的北京城市循环工况能够反映北京城市公交客车的实际运行状况,具有实用价值。     

高速公路货车交通事故分析

根据国内某典型重载高速公路近几年交通事故的统计,分析大货车与高速公路交通事故之间的统计关系,并就载重货车交通对高速公路运营安全性的影响进行了研究。结果表明,事故的发生与车辆的实际操纵性能有关,超载、不同车型之间运行车速的显著差异、行车注意力不集中和疲劳驾驶等是造成货车交通事故的主要原因。从工程、交通管理等角度对提高高速公路运营安全水平提出了相应的改进措施。     

Impact of driving style,behaviour and anger on crash involvement among Iranian intercity bus drivers

In developing countries such as Iran, due to the inadequate infrastructure for rail and air transportation facilities, intercity buses are the most common type of transportation for long distances. Because of the long hours of driving, bus driving is considered a challenging job. Moreover, given the high capacity of these vehicles, a small error from the driver could endanger many passengers' health. So, studying drivers' behaviours can be a key factor in decreasing the risk factors of crash involvement in these drivers. However, few studies have focused on intercity bus drivers' behaviours. This research uses a sample of 254 professional drivers that answered a self-report questionnaire on driving style (MDSI), driving behaviour (DBQ), and driving anger (DAS). A structural equation modelling (SEM) is used to investigate the psychometric properties of these questionnaires. The results show a positive correlation between maladaptive driving styles and driving behaviour, and a negative correlation between adaptive styles and driving behaviour. Significant differences are observed among drivers with and without crash history on their maladaptive driving styles and their driving anger scale. A binary logistic regression model is also developed to predict traffic crashes as a function of driving misbehaviour. The results suggest that factors related to driving anger are the main factors that increase the probability of misbehaviour and traffic crashes. The results also suggest that driving style and driving behaviour significantly predict crash risk among bus drivers. Aggressive driving is associated with an increased probability of crash involvement among intercity bus drivers. The findings can be used to inform the health promotion policies and provide regular interventions designed to improve driving safety among intercity bus drivers.     

The demand for public buses in sub-Saharan African cities: Case studies from Maputo and Nairobi

Despite the limited transportation options, public buses have been proved unpopular in many Sub-Saharan African cities. While the declining use of local buses in the developed world is often associated with increasing number of transport alternatives, relatively little is known about African cities. A substantial number of studies are focused on how to replace buses with the rapid transportation modes and less diagnosis is applied to the factors affecting the use of buses. Using household information survey, this paper attempts to investigate the factors affecting the demand for buses in Maputo and Nairobi by employing logistic regression approach.Results show both similarities and variations among the factors affecting the likelihood of using buses. For example, the likelihood of using buses decreases with vehicle ownership and employment status in the two cities. In addition, gender (female) has no effect on the likelihood of choosing buses over paratransit in both cities. Second, while age decreases the likelihood of choosing buses and residence location increases that in Maputo, the opposite is observed in the case of Nairobi City. The main implication of these findings is that there is a need to share the roles of public transportation between buses and paratransit.     

武汉市公交车典型行驶工况的构建

利用实测的公交车运行数据,建立符合公交车运营特点的行驶工况.首先将连续行驶数据进行短行程划分并计算各短行程的特征值;之后采用主成分分析将12个特征值降为4个主成分,利用相关系数法建立了武汉市公交车的综合行驶工况;同时采用聚类分析对短行程分类,构建了公交车在拥堵道路、较畅通道路、畅通道路3类交通条件下的行驶工况;各工况同实测数据的相关系数均超过了0.98.研究结果表明,该地区公交车平均运行速度为19.46 km/h,各行驶模式下的时间比例分别为:加速26.39%、减速23.61%、匀速33.33%、怠速16.67%.此外将所建立综合工况与燃油消耗量测试工况C-WTVC比较,发现二者在平均速度和怠速时间比例方面存在较大差别.因此有必要针对公交车专门开发测试工况,从而为交通和环保部门的公交运营管理提供指导.      

迎接高速公路时代—中国汽车相关技术问题的考察

中国正迎来高速公路时代，高速公路时代安全行车在技术因素方面涉及车辆的构造，道路设施与运行管理，在人的因素方面涉及驾驶习惯。保养与车检，安全运行的宣传教育与管理等。     

考虑驾驶风格的电动公交车能耗灰色关联投影-随机森林预测模型

为探索驾驶员驾驶行为与电动公交车能耗之间的关系，采用随机森林算法建立电动公交车能耗预测模型。为克服驾驶行为特征参数和样本数据的随机性对电动公交车能耗预测模型的负面影响，运用灰色关联投影法计算各驾驶行为特征参数的灰色关联度以及各样本数据的投影值，筛选出与能耗具有高关联性的驾驶行为特征参数作为模型的输入变量，以及相似度较高的样本数据作为训练集和测试集。同时，引入了与能耗具有显著相关性的驾驶风格变量以进一步提升模型的预测能力，运用K-means聚类方法将驾驶风格分类并得到驾驶风格标签。将驾驶风格标签和筛选后驾驶行为特征参数作为输入变量，单位里程能耗作为输出变量，基于筛选后的数据集建立了考虑驾驶风格的电动公交车能耗灰色关联投影-随机森林（GRP-RF）预测模型。基于广州市某线路电动公交车运营数据对模型进行检验，并运用该模型分析加速、制动和运行3种典型场景下相应驾驶行为特征参数对电动公交车能耗的影响。结果表明:该模型预测能耗的均方根误差（RMSE）和平均绝对百分比误差（MAPE）分别为0.001 8 kW·h/km和3.42%。相比于不考虑驾驶风格的GRP-RF模型和随机森林模型，该模型的RMSE分别降低了35.71%和48.57%，MAPE分别降低了38.82%和46.81%。研究结果表明:加速、制动和运行阶段的平均能耗分别为1.066，0.903 7，0.955 2 kW·h/km；为使各阶段能耗在相应均值以下，加速阶段应控制加速踏板开度在55%以内；制动阶段应控制制动踏板开度在25%以内；运行阶段应控制车速在40 km/h以内。      

Energy management and design optimization for a series-parallel PHEV city bus

Series-parallel PHEV city buses combine the advantages of series and parallel configurations and have been used in China. However, the design and energy management of series-parallel PHEV city buses based on Chinese driving conditions still need to be investigated. In this paper, an equivalent consumption minimization strategy is provided to optimize energy management for series-parallel PHEV city buses, and the process of the equivalent consumption minimization strategy for series-parallel is presented in this paper. Compared with the validated rule-based energy control strategy, ECMS shows a fuel economy improvement of 8.2 % in the CBCD (Chinese Bus Driving Cycle). Based on the optimal energy management, a design for a generator motor in the series-parallel configuration has been processed. The fuel consumption has been shown to decrease, with an increase in generator power, because the system with the higher generator power can work at a higher efficiency in the series mode and operate the engine in the high efficiency area in the parallel mode. Besides, in terms of costof- ownership for a PHEV bus for lifetime of 8 years, although the high generator power will lead to high purchase cost for series-parallel PHEV bus, a series-parallel PHEV city bus with a generator of 100 kW maximum power will still show small advantage in cost-of-ownership, based on current motor price and natural gas price.