新型电流变制动器的结构初步设计及性能分析

根据电流变(electro-rheological，ER)流体的力学性能并结合原有制动器的特点，设计一种能够更大幅度提高ER制动器制动力矩的新型ER制动器，给出其结构示意图和制动力矩的计算公式。通过对DF11机车制动时间和制动距离的仿真计算，显示在同样的外加电场和ER流体材料的情况下，新型ER制动器可大大缩短制动距离和制动时间，其制动性能是非常显著的。     

混合法多目标优化盘式制动器

介绍盘式制动器混合多目标优化问题数学模型的建立。提出以制动摩擦力矩和制动时间为主要优化目标的多目标函数 ,并采用 2种直接优化方法 (采用惩罚函数的SEEK和ADRANS子程序 )相结合进行优化。结果表明 ,该方法简便可靠、收敛速度快。     

真空助力器-制动主缸总成测试装置

根据汽车真空助力器—制动主缸总成技术条件及测试方法，研制了真空助力器—制动主缸总成测试装置与计算机控制系统。详述测试装置和控制系统的组成、功能、特点。为真空助力器—制动主缸总成性能在线检测提供了快速、准确、安全、可靠的装置和计算机测控系统。     

轿车制动钳总成的缸孔与活塞间隙匹配设计

针对球磨铸铁件材料的制动钳总成在低纬度地区高温工作环境中的可靠性和综合性能进行优化设计,减小因环境温度变化大对制动性能影响,提高制动钳总成的综合性能和使用寿命。     

Effect of advanced injection timing on the performance of rapeseed oil in diesel engines

Combustion studies on both diesel fuel and vegetable oil fuels, with the standard and advanced injection timing, were carried out using the same engine and test procedures so that comparative assessments may be made. The diesel engine principle demands self-ignition of the fuel as it is injected at some degrees before top dead centre (BTDC) into the hot compressed cylinder gas. Longer delays between injection and ignition lead to unacceptable rates of pressure rise with the result of diesel knock because too much fuel is ready to take part in premixed combustion. Alternative fuels have been noted to exhibit longer delay periods and slower burning rate especially at low load operating conditions hence resulting in late combustion in the expansion stroke. Advanced injection timing is expected to compensate these effects. The engine has standard injection timing of 30°C BTDC. The injection was first advanced by 5.5°C given injection timing of 35.5°C BTDC. The engine performance was very erratic on this timing. The injection was then advanced by 3.5°C and the effects are presented in this paper. The engine performance was smooth especially at low load levels. The ignition delay was reduced through advanced injection but tended to incur a slight increase in fuel consumption. Moderate advanced injection timing is recommended for low speed operations.     

鼓式制动器的热固耦合分析

制动器是车辆的重要组成部分,制动器的热稳定性对车辆等稳定性、安全性等有很大影响。在有限元软件环境中建立鼓式制动器的有限元模型,鼓式制动器加载条件按照实际安装情况加载,同时考虑螺栓预紧力对制动鼓仿真性能的影响。分析工况分为紧急制动和德国15次连续制动两种工况。仿真分析结果表明:螺栓预紧力对鼓式制动器的仿真分析结果影响较大;紧急制动的工况下制动鼓最高温度远低于德国15次连续制下的制动鼓最高温度;温度越高引起的热应力越大;给制动器的进一步改进提供指导依据。     

电动汽车复合制动系统状态估计控制算法

针对目前再生制动静态分配控制策略存在的问题,提出了基于复合制动系统结构的行车状态参数估计算法,并利用建立的硬件在环仿真环境仿真验证了算法对参数估计的效果.提出了基于行车状态估计的最高能量回收控制策略优化算法,仿真分析了算法优化前后的控制过程和效果.硬件在环仿真数据表明,优化后的策略有效提高了能量回收效率,防止了车轮的提...     

A THERMOMECHANICAL MODEL FOR THE ANALYSIS OF DISC BRAKE FRACTURE MECHANISMS

The aim of this article is to explain the damage mechanisms of disc brakes leading to macroscopic cracks on the friction surface. The work combines microanalysis of cracks and a thermomechanical modeling describing the thermal fatigue solicitation. The failure of disc brakes is discussed, giving indications of how to improve the design of this type of friction system in order to enhance its performances     

飞机刹车分配阀的余气故障分析

介绍了飞机刹车分配阀的工作原理和特点,分析了产生余气故障的原因。并在此基础上,提出了相应的解决措施,得出了一些有益的结论。     

Application of nano powdered rubber in friction materials

Styrene butadiene nano powdered rubber and nitrile-butadiene nano powdered rubber were used for manufacturing clutch facings, disc brake pads and brake linings to replace conventional styrene butadiene rubber and nitrile-butadiene rubber. The results of constant speed friction test and dynamometer test showed that nano powdered rubber can substantially improve properties of friction materials. The friction coefficient of friction materials modified with nano powdered rubber varies steadily with the change of temperature, and the wearing rate of friction materials is relatively low by using nano powdered rubber. These results indicate that nano powdered rubber has ideal application effect in various friction materials and is a kind of novel rubber modifier for friction materials.