中国客车产品面临的国际噪声限值挑战

2015年联合国欧洲经济委员会确定了加速行驶车外噪声法规ECE R51-03系列的限值,并于2016年7月1日起正式实施,中国客车产品将面临极为严峻的挑战。主要原因是中国与欧洲的客车产品存在尺寸、发动机功率等典型差异,而欧洲在限值制定过程并未充分考虑中国客车产品特征。结合大量验证试验提出适合中国国情的限值划分方案,并指出国内企业应借鉴日本经验,尽快介入ECE R51-03法规的后续修订过程,消除技术壁垒。     

多工况加速行驶车外噪声测量评价方法

欧洲经济委员会正在起草修订的新噪声法规ECE R51 03系列,要求对M1、N1类汽车进行多工况下的加速行驶车外噪声测量。阐述其测量方法产生的背景、发展过程及适用范围;结合验证试验解析多工况加速行驶车外噪声测量的试验流程,以及相应的三种评价方式。为汽车企业、大学及科研机构研究多工况下的加速行驶车外噪声测量与控制提供技术参考。     

中国特有轻型车辆面临的国际噪声限值挑战

2013年联合国欧洲经济委员会将确定加速行驶车外噪声法规ECE R51/03系列的限值,中国特有的轻型车辆即将面临较为严峻的挑战。主要原因是中国与欧洲轻型车辆存在典型差异,而欧洲在数据收集过程并未充分考虑中国特有的轻型车辆。对国内车辆大量的验证试验表明了中国典型轻型车辆噪声水平与轿车存在的差异,提出了适合中国国情的限值划分方案,并指出国内企业应借鉴日本经验,尽快介入欧盟法规制订过程,消除技术壁垒。     

加速行驶车外噪声快速试验方法

结合ISO 362-1：2007、ECE R51-03系列以及最新的GB1495草案所述试验方法的新要求,采用适当的试验流程,在现有设备基础上,集成和同步采集车速、发动机转速、整车行驶过程中的纵向加速度、油门踏板状态、整车在试验场地上的相对位置等测量参数,整合出一种汽车加速行驶车外噪声快速试验方法。     

汽车噪声限值预测模型与分析

汽车噪声是道路交通噪声的重要组成部分,直接影响城市道路交通声环境质量和居民日常生活,持续降低有关汽车噪声法规中汽车噪声限值有利于提高道路交通声环境质量.对某汽车噪声法规及其限值进行分析,采用最小二乘法建立汽车加速行驶时车外噪声限值的线性回归、二次回归预测模型,得到噪声限值预测值.从预测模型分析结果可知:二次回归预测模型...     

基于波束形成方法的货车车外加速噪声声源识别

综合基于波束形成的噪声源识别方法和外场车外加速噪声测量技术,构建一套完整的针对运动声源的车外加速噪声外场声源识别测试系统,给出了相应的测试计算流程与方法。利用该系统完成货车车外加速噪声声源识别试验,确定发动机为该货车车外加速噪声的主导噪声源,且对应最大噪声时刻发动机转速为２４００ｒ／ｍｉｎ。进一步的发动机噪声源识别结果表明：涡轮增压器、发电机、气缸盖罩是其主要噪声辐射源。     

中国车企参加国际法规工作技术要素研究

当前,世界各大汽车企业都在中国车市上获得丰满回报,中国自主品牌产品却在国内生存艰难,"走出去"又面临着国际市场准入方面的法规壁垒。国内的汽车研发,被动的被国际法规牵着走。针对此问题,通过研究WP.29-Blue-2012-1Chinese~([1]),找到1958协议和1998协议中规定的国际汽车法规工作技术要素,结合UN ECE r51.03微车法规技术提案的争取成功过程经验总结,指出国际法规为国际汽车巨头贸易服务的具体实现方式,为中国车企提供参加国际标准制修订过程中维护企业利益的方法。     

低速汽车噪声标准与应用

研究我国低速汽车噪声标准的发展和现状,分析现行标准应用中应注意的问题,指出我国对低速汽车加速行驶车外噪声要求偏低,而且对在用低速汽车没有噪声限值标准,强调出台更为严格的标准和法规对低速汽车噪声排放监控的重要性,旨在有效地控制汽车噪声污染,保护环境。     

低速汽车噪声标准与应用研究

研究了我国低速汽车噪声标准的发展和现状,分析了现行标准应用中应注意的问题,指出我国对低速汽车加速行驶车外噪声要求偏低,而且对在用低速汽车没有噪声限值标准,强调了出台更为严格的标准和法规对低速汽车噪声排放监控的重要性,旨在有效地控制汽车噪声污染,保护环境。     

汽车整车半消声室的设计与建设

参照ISO 362、ECE R51、GB 1495-2002标准中汽车整车噪声测试对声学测试环境的要求,按照GB 6882-1986、ISO 3745-2003标准和实际使用需求提出国家汽车质量监督检验中心（襄樊）汽车整车半消声室建设的指标。实验室建成后通过中国计量科学研究院鉴定测试,达到设计要求。详细介绍汽车整车半消声室的设计方法、建设情况和鉴定结果。     

基于ANSYS的多轴汽车振动响应分析

为了高效预测路面不平度输入下多轴汽车悬挂质量某一位置处的振动响应特性,依据多体动力学理论,利用ANSYS仿真工具建立多轴汽车的七自由度动力学仿真模型。在整车发动机定转速的试验基础上,运用理论分析、仿真计算相结合的方法,根据建立的模型对整车进行仿真分析与研究。结果表明仿真计算结果与试验结果基本一致,可见,所提出的动力学模型和分析方法具有较好的可信度。仿真结果表明：在路面不平度输入下,影响悬挂质量[-]6 m～[-]4 m处的加速度响应以第1阶固有频率为主;而在[-]2 m～4 m处以第2阶固有频率为主,尤其是在悬挂质量的后端;第2阶固有频率是影响多轴汽车加速度振动响应特性的最主要的因素,改善该多轴汽车的平顺性需把研究重点放在多轴汽车的第三四车轴的悬架系统上。     

LIM propulsion system development for transit

The Urban Transportation Development (UTDC) Corporation has developed an Intermediate Capacity Transit System (ICTS). The concept is based on steel-wheel on steel-rail for suspension and guidance, four steerable axles in two trucks, linear induction motors for propulsion, moving-block automatic train control, and elevated guideway. The technologies were chosen to provide a quiet, environmentally asthetic, comfortable ride, frequent service and medium capacity. The usual transit requirements for safety, reliability and maintainability were principal design influences. The concurrent requirements of frequent service, intermediate capacity (12-20,000 pphpd) and demand responsive service lead to the need for adhesion independent braking. Short station lengths and short by-pass guideway sections require maintaining high acceleration levels to 60% of top speed. Only a linear induction motor satisfied the conceptual requirements. The work of analysis, design, manufacture and test have followed the selection of a LIM as the prime-mover of the ICTS vehicles. This paper reports the findings of the vehicle testing of the LIM.     

Risk appraisal of passing zones on two-lane rural highways and policy applications

Passing on two-lane rural highways is associated with risks of head-on collision resulting from unsafe completion of passing maneuvers in the opposite traffic lane. In this paper, we explore the use of time-to-collision (TTC) as a surrogate safety measure of the risk associated with passing maneuvers. Logistic regression models to predict the probability to end the passing maneuver with TTC less than 2 or 3 s-threshold were developed with the time-gap from initiation of the maneuver to arrival of the opposite vehicle (effective accepted gap), and the passing duration as explanatory variables. The data used for model estimation was collected using stationary tripod-mounted camcorders at 19 passing zones in Uganda. Results showed that passing maneuvers completed with TTC less than 3 s are unsafe and often involved sudden speed reduction, flashing headlights, and lateral shift to shoulders. Model sensitivity analysis was conducted for observed passing durations involving passenger cars or short trucks (2–3 axles), and long trucks (4–7 axles) as the passed vehicles for 3 s TTC-threshold. Three risk levels were proposed based on the probability to complete passing maneuvers with TTC less than 3 s for a range of opposite direction traffic volumes. Applications of the results for safety improvements of two-lane rural highways are also discussed.     

Design of a composite roll bar for the improvement of bus rollover crashworthiness

This paper discusses a new carbon–epoxy composite roll bar installed in a bus. It aim of this new roll bar is to satisfy the stiffness and strength requirements and maintain the traditional metallic structural parts reinforced by the composite roll bar. In this study, bus rollover was investigated the implementation of adequate material models for accurate treatment. The benefits of this new material include a lower center of gravity and reduced mass and roll moment of inertia of the vehicle. The performance of the structures with regard to ECE R66 was compared between the initial and composite roll bar bus models. The bus structure reinforced by the composite roll bar was able to secure a substantial margin of the survival zone as well as to meet the requirement specified by ECE R66.     

Application potential of high performance steels for weight reduction and efficiency increase in commercial vehicles

The fast-growing economy and the gradually established highway system have boosted the road transportation for both passenger and cargo over the last decade in China.From 2000 to 2010 Chinese GDP increased by around10.15%annually and the sales of medium and heavy trucks by around 18.87%(sales increased from 0.2 million in 2000 to 1.3 million in 2010) according to the National Bureau of Statistics of People's Republic of China.Today commercial vehicles consume almost the same amount of fuel as passenger cars in China although the number of commercial vehicles is only about one fourth of passenger cars.It is estimated that around 50%of imported fuel to China each year will be consumed by vehicle transportation.This situation will worsen fuel shortage problems in the long run and at the same time it is partially responsible for the everworsening air pollution in China.Due to the widespread overloading in China,lightweight development in commercial vehicles has fallen far behind that of passenger cars with the consequences that Chinese commercial vehicles consume in average about 20%more fuel,especially the heavy trucks,compared to European models.Under these circumstances it is essential to reduce the vehicle fuel consumption and increase the transport efficiency.The key solution thereby is to implement lightweight design in commercial vehicles as it has been successfully practiced over the last decade in the passenger cars.This paper summarizes highlights given in presentations during the "International seminar on the application of high strength steels in light weight commercial vehicles" with the focus on the development and application of Nb alloyed high performance steels made for lightweight commercial vehicles.     

某车辆动力总成异常振动分析与改进

针对某SUV车柴油机动力总成产生异常振动导致操纵手柄剧烈振动这一实际问题,将振动试验测试与有限元仿真分析结合起来研究动力总成的振动动态特性。通过整车道路试验及转鼓试验,发现柴油机工作转速的二阶激励激起了动力总成系统共振,通过采用有限元方法建立了一种柴油机动力总成振动分析模型,计算分析了此动力总成的振动固有频率和固有振型,找到了导致动力总成弯曲刚度变差的原因—飞轮壳结构刚度不足。在验证了有限元仿真模型计算合理性基础上,通过改进设计飞轮壳结构,提高了动力总成的固有频率,使其避开了共振频率区间,最终消除了操纵手柄的异常振动。该试验与仿真分析方法对解决同类工程问题具有参考指导和应用价值。     

Analysis of large truck crash severity using heteroskedastic ordered probit models

Long-combination vehicles (LCVs) have significant potential to increase economic productivity for shippers and carriers by decreasing the number of truck trips, thus reducing costs. However, size and weight regulations, triggered by safety concerns and, in some cases, infrastructure investment concerns, have prevented large-scale adoption of such vehicles. Information on actual crash performance is needed. To this end, this work uses standard and heteroskedastic ordered probit models, along with the United States’ Large Truck Crash Causation Study, General Estimates System, and Vehicle Inventory and Use Survey data sets, to study the impact of vehicle, occupant, driver, and environmental characteristics on injury outcomes for those involved in crashes with heavy-duty trucks. Results suggest that the likelihood of fatalities and severe injury is estimated to rise with the number of trailers, but fall with the truck length and gross vehicle weight rating (GVWR). While findings suggest that fatality likelihood for two-trailer LCVs is higher than that of single-trailer non-LCVs and other trucks, controlling for exposure risk suggest that total crash costs of LCVs are lower (per vehicle-mile traveled) than those of other trucks.