汽车使用条件对维护周期影响的分析

对汽车进行维护保养,目的是为了延长其使用寿命。目前维护保养周期的确定通常是以汽车的行驶时间或行驶里程为依据。但是,由于汽车使用条件(如:运行地区的地理环境、气候、风沙条件,汽车运行负荷、常用速度、操作频率和燃、润油料的品质等)的不同,对汽车使用性能的降低程度影响     

应正确使用汽车的“液体”

介绍汽车用燃料，润滑材料，制动液与冷却液的国家新标准，新牌号及正确使用方法。     

添加燃油添加剂产品前后汽车相关性能的比对试验

笔者选择了市场上畅销的某三个品牌（甲、乙、丙）的燃油添加剂产品，分别对添加了三个品牌（甲、乙、丙）的燃油添加剂之前和之后的汽车的动力性（加速性能）、经济性、怠速排气污染物等三个方面进行了比对试验。指出，要正确选择合适的燃油添加剂产品，没有一种燃油添加剂产品能适合所有的汽车；燃油添加剂产品的节油效能达到5％是比较客观的，如果说能达到15％以上，不太现实；燃油添加剂产品一般侧重于汽车尾气的改善。     

润滑油添加剂(MoS2)对发动机性能影响的试验研究

文章通过试验对比的方法就MOS2用作润滑油添加剂对发动机性能的影响进行了分析研究,指出MOS2作为润滑油添加剂能够提高气缸压缩压力、减少摩擦损失而提高发动机性能。同时,MOS2与金属表面产生的物理吸附膜在特殊的工况条件下将对发动机起到保护作用。MOS2用作润滑油添加剂的关键技术在于其平均粒度达到0.5μm以下。     

添加剂对载货汽车使用寿命的影响

使用化学添加剂能延长载货汽车的使用寿命，重型载货汽车停车维修时间的40％是由冷却系的故障造成的，如果按要求冲洗该系统，并使用适当浓度的优质化学剂时，就能大幅度减少这个百分数，冷却液添加剂外加适当浓度的防冻液，可预防发动机缸体和冷却系零部件内部的水垢，预防缸套的穴蚀，凝胶体的形成，并抑制腐蚀，目前发动机润滑油中常见的有粘度指数改进剂等七种添加剂，添加剂的品质及含量决定了机油的性能，从而改进了燃油品质。     

轮胎结构对汽车使用性能影响的试验研究

本文以轿车上常用的子午线轮胎为例,通过理论分析和装车试验,对比、评价子午线轮胎的结构特性对汽车性能的影响,并以汽车的使用性能为侧重点,探讨轮胎与整车匹配的     

氯化添加剂是汽车润滑油的好伴侣吗？

在过去几年中,在市场和产品的广告宣传中,用于提高发动机性能的发动机润滑油添加剂正呈现出稳步的持续增长。许多添加剂的制造商经常以“金属改善剂”或者“处理剂”的名义宣称他们的产品能够处理发动机内部的金属摩擦表面,并且不会改善发动机润滑油的性能。     

汽车发动机冷却液的正确选用

现在，大部分汽车发动机采用了强制循环水冷却系，冷却液是冷却系中的传热介质，主要具有良好的冷却、防沸、防冻、防腐、防泡和防垢等性能。     

清净分散剂的复合对汽油机油使用性能的影响

着重介绍汽油机油研制中广泛使用的几种清净分散剂的单剂性能及其复合使用对汽油机油的高温清净性能、抗磨性能、抗氧化性能的影响。根据模拟评定试验数据，提出了几种清净剂分散剂的最佳比例。     

添加剂对汔车性能的影响

汽车使用的添加剂有燃油添加剂、润滑油添加剂、冷却液添加剂等.它的质量以及使用水平对汽车使用性能会产生哪些影响,应如何选择呢?     

Influence of shock absorber wearing on vehicle brake performance

In order to safely maintain a vehicle, it is necessary to verify the most important systems that affect safety during Periodic Motor Vehicle Inspections (PMVIs). In a previous paper, a test method and validation criteria were suggested by the authors to verify shock absorber status during PMVIs, as they are a fundamental component that may wear out during a vehicle’s life. In this paper, variations of the performance of the vehicle’s brakes resulting from shock absorber wearing have been analyzed, in order to confirm whether the suggested criteria is valid for taking into account longitudinal forces and pitch movement on the vehicle. A simulation-based study was conducted with several configurations of a worn damper on a vehicle driving on two virtual roads: smooth and undulating. The results confirmed that the damping coefficient established as an acceptable value to verify the shock absorber status in PMVIs is also valid considering the forces involved in a braking maneuver.     

Analysis of handling performance based on simplified lateral vehicle dynamics

In this article, the analysis methods for vehicle handling performance are studied. Using simple models, dynamic characteristic parameters such as yaw, natural frequency, and the damping coefficient of a vehicle can be theoretically formulated. Here, the vehicle is simplified by a bicycle (single-track) model, and the tire is modeled by an equivalent cornering stiffness and first order lag. From the experimental road data, the tire model parameters (equivalent cornering stiffness and time lag constant) are extracted. These parameters are then inserted into the theoretically formulated equations of dynamic characteristic parameters. For the purpose of validating the efficiency of the suggested methods, experimental road tests (where the cars have different handling performances) are performed. The results show that vehicle handling performance can be sufficiently represented by the suggested dynamic characteristic parameters. So, it is concluded that the proposed method has practical use for the development of new cars or for the comparison of similar cars since the evaluations of the vehicle handling performance can be efficiently determined by the suggested dynamic characteristic parameters.     

基于虚拟仪器的汽车制动性能测试系统

基于“虚拟仪器”的思想,采用“便携式”系统集成方案,进行了汽车制动性能测试系统的开发。给出了测试系统的组成结构,阐述了测试流程和模块功能,并提出了数据处理方法。     

Railway vehicle performance optimisation using virtual homologation

Unlike regular automotive vehicles, which are designed to travel in different types of roads, railway vehicles travel mostly in the same route during their life cycle. To accept the operation of a railway vehicle in a particular network, a homologation process is required according to local standard regulations. In Europe, the standards EN 14363 and UIC 518, which are used for railway vehicle acceptance, require on-track tests and/or numerical simulations. An important advantage of using virtual homologation is the reduction of the high costs associated with on-track tests by studying the railway vehicle performance in different operation conditions. This work proposes a methodology for the improvement of railway vehicle design with the objective of its operation in selected railway tracks by using optimisation. The analyses required for the vehicle improvement are performed under control of the optimisation method global and local optimisation using direct search. To quantify the performance of the vehicle, a new objective function is proposed, which includes: a Dynamic Performance Index, defined as a weighted sum of the indices obtained from the virtual homologation process; the non-compensated acceleration, which is related to the operational velocity; and a penalty associated with cases where the vehicle presents an unacceptable dynamic behaviour according to the standards. Thus, the optimisation process intends not only to improve the quality of the vehicle in terms of running safety and ride quality, but also to increase the vehicle availability via the reduction of the time for a journey while ensuring its operational acceptance under the standards. The design variables include the suspension characteristics and the operational velocity of the vehicle, which are allowed to vary in an acceptable range of variation. The results of the optimisation lead to a global minimum of the objective function in which the suspensions characteristics of the vehicle are optimal for the track, the maximum operational velocity is increased while the safety and ride quality measures of the vehicle, as defined by homologation standards, are either maintained in acceptable values or improved.     

Effect of drowsiness on driving performance variables of commercial vehicle drivers

Driver drowsiness is a major safety concern, especially among commercial vehicle drivers, and is responsible for thousands of accidents and numerous fatalities every year. The design of a drowsiness detection system is based on identifying suitable driver-related and/or vehicle-related variables that are correlated to the driver’s level of drowsiness. Among different candidates, vehicle control variables seem to be more promising since they are unobtrusive, easy to implement, and cost effective. This paper focuses on in-depth analysis of different driver-vehicle control variables, e.g., steering angle, lane keeping, etc. that are correlated with the level of drowsiness. The goal is to find relationships and to characterize the effect of a driver’s drowsiness on measurable vehicle or driving variables and set up a framework for developing a drowsiness detection system. Several commercial drivers were tested in a simulated environment and different variables were recorded. This study shows that drowsiness has a major impact on lane keeping and steering control behavior. The correlation of the number and type of accidents with the level of drowsiness was also examined. Significant patterns in lateral position variations and steering corrections were observed, and two phases of drowsiness-related degradation in steering control were identified. The two steering degradation phases examined are suitable features for use in drowsiness detection systems.     

Curving performance simulation of an EMS-type Maglev vehicle

For electromagnetic suspension (EMS) type urban Maglev vehicles using a U-shaped electromagnet, the levitation and guidance forces are generated by only one electromagnet. Although the levitation force is actively controlled by changing the voltage of the electromagnet, the guidance force is passively determined by the levitation force. In addition, the curve negotiation performance of EMS-type urban Maglev vehicles using a U-shaped electromagnet must be considered, because an urban guideway may have some curves with shorter radii. It is, therefore, necessary to predict the curving performance with the greatest accuracy possible, in order to improve electromagnetic suspension and establish guideway design specifications. The objective is to establish a new dynamic modelling technique, so as to achieve more realistic curving simulation and thus to more accurately evaluate the curving performance of an EMS-type Maglev vehicle. The use of a full vehicle multibody dynamic model is proposed, and is applied to the evaluation of curving performance. Design changes are also investigated to obtain the bogie design directions for minimising variation in the lateral air gap, which is a criterion for curving performance.     

利用发动机MAP图对整车动力性与经济性的优化

整车的动力性和经济性是整车性能的重要指标,然而动力性和经济性往往被认为是相互制约的。利用MAP图,通过合理匹配传动比,综合提高整车的动力性和经济性两种性能,对提高整车的开发质量无疑是非常重要的。     

国产混凝土专用汽车性能特点及使用

与一般的货物运输不同，混凝土运输有四大性能特点：一是专业性强，二是服务性强、均衡性差，三是时间性强，四是运距短。     

基于底盘测功机的整车性能衰退研究

汽车在行驶一定里程后其性能会发生一定的衰退,在底盘测功机上进行汽车性能对比试验能减少许多不可控的因素对试验结果的影响。通过在底盘测功机上对某卡车进行动力性、经济性试验,对比分析测量车辆在行驶不同公里数后的动力性、经济性试验结果,阐述底盘测功机在整车性能衰退研究上的应用。