关于确定单缸柴油机可靠性寿命的方法的设想

可靠性是产品的重要质量指标之一,产品可靠性的提高,意味着用户对产品可以放心使用,减少维修费用,提高工作效率保证设备和人身的安全等,使制造厂的信誉提高。二十年来,随着现代技术的发展,产品向大型化、高参数化、性能优异化、以及使     

小型单缸柴油机的排放控制技术现状及其前景分析

针对目前国内外研究状况,从燃料、燃烧和排气后处理等方面介绍了小型单缸柴油机的排放控制技术及其特点和存在的问题,并对其前景进行简要的分析。     

单缸柴油机动力不足浅析

柴油机无力故障较常见,但是原因较多;主要有油、气和机器自身故障,有针对性的分析,及时更换故障零件并及时进行维护保养。发动机本身的问题是造成动力不足的另一不容忽视原因;常见的是活塞、缸套的早期磨损;燃料喷射系统的故障会直接影响发动机的动力;缸盖有故障的情况也对柴油机输出功率有较大的影响。     

单缸柴油机曲轴连杆颈的加工

１前言为保证曲轴有足够的强度、刚度、韧性和耐磨性,我厂生产的６０～８０系列单缸风冷柴油机曲轴全部采用４５号钢锻造毛坯,粗车后调质２０７～３０２ＨＢ（图１）。图１１７５７—１型风冷柴油机曲轴对比球墨铸铁等其他材料的单缸机曲轴,其连杆颈部位、平衡重内颊板...     

基于MATLAB/SIMULINK的单缸柴油机活塞曲轴系统动力学仿真

精确推导了单缸柴油机曲柄滑块机构的动力学方程,以MATLAB/SIMULINK为平台建立了机构的动力学仿真的框图模型,得出了曲柄连杆机构各运动部件的运动规律及受力,为单缸柴油机的活塞曲轴系统的优化设计提供了参考。     

基于虚拟样机的柴油机主轴径轴承动力学特性研究

主要以建立柴油机动力学虚拟样机为目的,使用内燃机动力学模拟软件GT-CRANK对铁路机车16V240ZJ型柴油机进行动力学建模,对比在不同的边界条件下,其各主轴径轴承的油膜厚度、轴心轨迹等特性的变化规律,进而确定相对较好的设计参数,为机车柴油机的改进设计提供依据。     

单缸柴油机机械调速器的结构分析及故障预防

从柴油机机械调速器的结构分析、工况作用及故障预防三个方面,阐明了机械调速器的功能,已演变成为使柴油机在最佳工况下工作并发挥潜能,还进一步走向了实现对柴油机的全面控制。     

单缸内燃机曲轴系统的动力学研究

以单缸柴油机为例,对曲轴轴心在气缸扭转力矩的作用下的轨迹进行了仿真,得到了轴心的响应曲线,并对其结果进行了分析。结果表明,数值计算结果与解析分析结果有较好的一致性。     

ZL1115型立式直联单缸柴油机(三等奖)

ZL1115立式直联柴油机是根据国家科技支撑计划子课题《节能型小型拖拉机配套发动机研究与开发》的任务书要求开发的,属于机械装置中的发动机领域。     

Precise instrumentation of a diesel single-cylinder research engine

The accuracy of any empirical result is a direct consequence of the quality of experimental setup and the strict control over testing conditions. For internal combustion engines, a large number of parameters that also exhibit complex interdependence may significantly affect the engine performance. Therefore, this work describes the essentials required to establish a high-quality diesel engine research laboratory. A single-cylinder diesel engine is taken as the fundamental building block and the requirements for all essential sub-systems including fuel, intake, exhaust, coolant and exhaust gas recirculation (EGR) are laid out. The measurement and analysis of cylinder pressure, and exhaust gas sampling/conditioning requirements for emission measurement are discussed in detail. The independent control of EGR and intake boost is also highlighted. The measurement and analysis techniques are supported with empirical data from a single-cylinder diesel engine setup. The emphasis is on providing the necessary guidelines for setting up a fully-instrumented diesel engine test laboratory.     

单缸柴油机喷油系统的模拟计算与试验研究

利用AVL-HYDISM模拟软件建立了1105柴油机喷油系统的仿真模型,模拟了此柴油机标定工况下的喷油性能,从高压油管泵端压力以及嘴端压力两方面与试验值进行了比较,同时计算得出了样机燃油喷射规律以及压力室油压.分析了样机不足,通过改进供油凸轮使得燃油喷射压力得到提高.     

Corrosive wear in crosshead diesel engines

Existing theories describe corrosive wear in crosshead diesel engines in terms of acid condensation, when the temperature in the combustion space drops below the dew point. Here a theory is proposed which stresses the role of alkaline cylinder lubricants in protecting the metal surface. Calculated liner wear rates as a function of fuel sulphur content, feed rate and alkalinity of the oil, and axial position are in satisfactory agreement with experimental data.     

High-temperature tribology of future diesel engines

Future diesel engines will be operated at higher cycle temperatures. These higher cycle temperatures will invariably pose tribological problems of the top ring, piston, valve seats, and valve guides. Current lubricating oil with a thermal oxidative stability up to 204°C will be inadequate: polyol ester-base formulated synthetic oil, such as Stauffer Chemical SDL-1 or US TACOM MRI-1, with 310°C thermal oxidative stability could possibly be the next generation of lubricating oil. However, as we get nearer to the time when diesel engines will be constructed in advanced structural ceramics or composites for ‘adiabatic’operation, the thermal stability of the lubricating oil will have to approach 445°C. To withstand a top ring reversal temperature beyond 310°C, polyphenyl ether base oil and other high-temperature liquid lubricants are sought, but the highly aromatic polyphenyl ether type oil has thus far shown little promise for this application. The hybrid piston with solid lubricated top ring has potential. Densified Cr₂O₃ on Cr₂O₃ has demonstrated the possibility of operating at 380°C top ring reversal temperature, with acceptable wear and life. NASA PS212 with Stellite 6B has also been tested without a liquid lubricant. The tribological needs of the next generation of high-output, high-temperature diesel engines can therefore be met with the synthetic polyol ester base, cost-effective, formulated lubricant. The adiabatic ceramic engine will require much higher temperature capability. To this end, tribologists will have to direct their efforts to other higher temperature liquid lubricants and to solid lubricants. A laboratory coefficient of friction of < 0.06 must be achieved in order to maintain acceptable brake-specific fuel consumption. This target is based on cast iron on cast iron with lubricating oil, and it must be achieved with acceptable wear and cost.     

基于可变风险SVM模型的柴油机故障诊断技术

针对传统故障模式识别方法不能区别不同误判所造成损失不同的问题,提出了可变风险支持向量机(SVM)模型,对传统SVM模型的最优分类面进行重新设计,在利用实际数据识别故障的同时融入专家经验,使故障识别结果更具可靠性,该方法已成功应用于柴油机故障诊断.     

Optimization study on a single-cylinder compressed air engine

The current research of compressed air engine(CAE) mainly focused on simulations and system integrations. However, energy efficiency and output torque of the CAE is limited, which restricts its application and popularization. In this paper, the working principles of CAE are briefly introduced. To set a foundation for the study on the optimization of the CAE, the basic mathematical model of working processes is set up. A pressure-compensated valve which can reduce the inertia force of the valve is proposed. To verify the mathematical model, the prototype with the newly designed pressure-compensated intake valve is built and the experiment is carried out, simulation and experimental results of the CAE are conducted, and pressures inside the cylinder and output torque of the CAE are obtained. Orthogonal design and grey relation analysis are utilized to optimize structural parameters. The experimental and optimized results show that, first of all, pressure inside the cylinder has the same changing tendency in both simulation curve and experimental curve. Secondly, the highest average output torque is obtained at the highest intake pressure and the lowest rotate speed. Thirdly, the optimization of the single-cylinder CAE can improve the working efficiency from an original 21.95% to 50.1%, an overall increase of 28.15%, and the average output torque increases also increases from 22.047 5 N · m to 22.439 N · m. This research designs a single-cylinder CAE with pressure-compensated intake valve, and proposes a structural parameters design method which improves the single-cylinder CAE performance.     

A study of the fouling characteristics of EGR coolers in diesel engines

Diesel emission regulations have recently become more severe. An important goal in diesel engine research is the development of methods to reduce the emissions of NOx and PM (particulate matter). Cooled EGR (exhaust gas recirculation) system has been widely used to reduce the NOx and PM emissions of light-duty diesel engines. In this study, numerical analyses, rig tests and engine tests were performed to assess how changes in internal shape characteristics can improve the heat exchange efficiencies of EGR coolers. The heat exchange efficiencies of EGR coolers have been numerically and experimentally measured during a fouling process. The results show that the second type of oval EGR cooler tested (oval #2) exhibited better heat exchange efficiency than either the first type of oval EGR cooler was tested (oval #1) or the shell and tube cooler examined. The turbulence generated in exhaust gas flows by the wavy-finned design of the oval EGR coolers facilitated PM desorption that allows these coolers to self-purify. With respect to the two similar oval EGR coolers, the cooler with fin pitch 4 mm has better efficiency than the cooler with fin pitch 6 mm due to differences in the heat transfer areas of these coolers. Both CFD analyses involving extreme conditions of engine operation and engine fouling tests involving conditions experienced during vehicular operation indicate that the two oval coolers differed by less than 4% with respect to both initial heat transfer efficiency and heat transfer efficiency after a 78-hour fouling test.     

Modelling of lubricant oil alkalinity in diesel engines

During the operation of a diesel engine, alkaline additives are gradually exhausted in neutralizing the acidic products of combustion. This is manifested by the decrease in total base number (TBN) value of engine oil during usage. The present work is an attempt to model the rate of TBN depletion in a diesel engine. Various models in vogue are discussed. A correlation between ‘system variables’ and the rate of TBN depletion is presented. Methods of multiple regression analysis are applied to the experimental data to establish the correlation. The coefficient of correlation for the proposed model is 0.9888. At 99% confidence level the chi-square test is successful, proving that the regression model is acceptable.