Supercharging performance of a gasoline engine with a supercharger

Supercharging of intake air can improve the engine power and combustion characteristics by boosting the intake pressure above atmospheric pressure. In this work, the supercharging performance of a supercharged gasoline engine was discussed on the basis of experimental investigation. The investigation results showed that the output and torque performance of a supercharged engine were improved in comparison with the naturally aspirated engine. In the engine system with a supercharger, owing to supercharging of intake air into the cylinder, the combustion pressure, the rate of heat release, and the burning rate of fuel-air mixture were found to be higher than those of the naturally aspirated engine. In this paper, the effect of the drive pulley ratio and the pressure ratio of supercharger, and the other factors on the supercharging performance were also investigated.     

发动机高原性能研究现状与展望

介绍了发动机高原性能的试验与仿真研究现状,提出发动机高原热平衡研究与新型涡轮增压技术的开发将是今后发动机高原性能研究的重点方向。     

Measurement and simulation of fuel injection pipe pressure and study of its effect on the heat release in a direct injection diesel engine

Fuel injection pipe pressures are measured and simulated to study the effect of fuel injection system characteristies on the heat release in a direct injection diesel engine. The fuel injection simulation is based on a linear model. The governing equations are solved by the finite difference method. The measured fuel pipe pressures and the simulated fuel pipe pressures matched well to each other except for the interval when the nozzle is closing. The effects of the fuel pipe length and the nozzle opening pressure are tested. The longer fuel pipe length causes proportional retardation of the fuel injection time. The higher nozzle opening pressure results in increase of the maximum fuel pipe pressure and shorter combustion duration.     

汽油添加剂对改善发动机性能的试验研究

本文叙述了汽油添加剂的主要作用和分类,并通过发动机台架试验研究了美狮汽油添加剂对发动机经济性及排气净化的影响,试验结果表明汽油中添加体积分数为01%的美狮汽油添加剂能够改善发动机经济性及排放性能。     

六缸柴油机性能模拟研究

本研究利用AVL BOOST建立了某六缸柴油机相应的计算模型。计算结果表明,模型可以适用于该发动机的性能模拟计算。利用该模型对其压缩比进行优化,最后获得合适的压缩比,为发动机的设计提供了理论依据。     

发动机性能恢复剂作用效果的试验研究

本文对目前市上几种发动机性能恢复作用效果进行了大量的发动机性能试验,证实了此类添加剂的作用效果,并对其作用机理进行了分析。     

轮胎胎面单元挤压膜特性分析

建立平行四边形胎单元挤压膜问题的数学模型并进行了数值求解,分析了胎面单元设计要素对轮胎薄膜湿牵引性能的影响,为轮胎胎面单元抗湿滑设计提供了理论依据。     

应用无网格法进行发动机悬置软垫裂纹扩展模拟

根据发动机悬置软垫的工作环境及橡胶材料的力学特性,将空间问题简化成平面问题。针对传统有限元方法和边界元方法模拟裂纹沿任意方向扩展存在的不足,应用新型数值模拟方法-无网格局部彼得洛夫-迦辽金方法,一种纯无网格法,对具有初始裂纹的发动机悬置软垫进行了断裂模拟,得到了裂纹的轨迹。     

GDH512电主轴振动特性分析

以GDH512主轴为研究对象,建立了轴和角接触轴承的等效动力学模型。研究了轴承等效刚度和预紧力参数之间的关系及对主轴系统固有频率影响规律,通过模态分析确定主轴部件的固有频率和振型,并对模型进行谐响应分析,最后用试验验证有限元模型。     

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.     

某型发动机油封装置的国产化设计

简述了某型发动机油封设备的功用、组成、工作原理及设计改进,说明在研制过程中所使用的主要部附件的特点。     

航空发动机短舱空间温度分布数值模拟与分析

通过分析飞机发动机短舱的结构特点,发展了短舱空间温度分布的一维和三维数值计算方法.针对某型涡扇发动机的几种飞行状态,确立了其短舱流动和换热的计算模型,数值模拟了发动机短舱内的温度分布,并对计算结果进行了比较和分析.从计算结果可以看出,沿轴向短舱内的温度分布规律几乎与涡扇发动机沿轴向的温度分布规律是一致的.因此,若保证短舱内的温度不超温,必须降低涡扇发动机向短舱内的热传递,特别是涡扇发动机高温部件向短舱内的传热.     

基于DEA的加工单元绩效改进

加工单元是制造企业的最小生产单位,其绩效评价涉及许多指标,包括质量指标、时间指标和财务指标等.如何将不同指标进行综合评价是企业生产管理者所关注的问题.现对DEA的不同模型进行了研究,并进一步通过C2R的效率排序模型对水平比较和连续改进方法进行了探讨.通过一个实际的对20个加工单元进行相对绩效分析的案例,讨论了加工单元绩效评价和改进的具体运用方法.     

汽车发动机零件磨损机理分析

零件磨损是造成汽车发动机故障产生的主要原因之一。为了提高汽车发动机的工作可靠性，本文重要探讨了汽车发动机的使用条件和零件的表面质量等因素对零件磨损影响的机理，分析了影响零件磨损的具体原因。     

Windmilling characteristics of centrifugal-flow turbojets

A new nondimensional method for predicting the windmilling performance of centrifugal flow turbojet engines in flight has been developed. The method incorporates loss correlations to estimate the performance of major engine components. Given basic engine geometry, flight Mach number, and ambient conditions, this method predicts transient and steady-state windmilling performance. Thus, this method can be used during the preliminary design stage when detailed hardware geometry and component performance data are not yet available. A nondimensional time parameter is newly defined, and using this parameter, the transient performance of different types of turbojets (e.g. centrifugal vs. axial) is compared. In addition, the predictions’ sensitivity to loss correlations, slip factors, and inlet ambient temperatures are analyzed.     

基于知识的摩托车发动机设计支持技术分析

在分析当前摩托车发动机设计中存在问题的基础上,论述市场竞争对摩托车发动机设计提出的要求,给出基于知识的发动机设计系统的主要内容。     

卷积码的仿真和性能分析

主要分析了卷积码的基本原理和编码方式,并对CDMA通信系统中的信道编码相关内容进行了概述,研究了卷积码的编码原理和算法,对卷积码的编码具体实现过程进行了详细的分析.通过VHDL语言程序对影响卷积码性能的几个重要参数进行了仿真,仿真结果表明,卷积码的性能优于分组码.     

两自由度并联机构性能指标分析

对两自由度2SPU+U并联机构进行了速度全域性能指标分析,绘出了上述性能指标图谱.针对速度全域性能指标的不足提出线速度全域性能波动指标和角速度全域性能波动指标公式,该指标可更好的反映机构线速度和角速度在整个工作空间内的运动性能波动情况.通过单变量分析法分析了关键部件尺寸变化对机构性能波动指标的影响,得到尺寸变化对机构性...     

Method for accurate measurements of detonations in motorbike high speed racing engine

All high-efficiency engines are inclined to destruction tendencies in consequence of detonation combustion. Most often the producers of engines solve this problem with a limitation of a maximum output performance but therefore there is decreased an efficiency of fuel utilization. When the detonation caused by pre-ignition and postignition, it is generally known that strong vibrations from the combustion chamber develop from impact of that combustion pressure. This will affect the engine. Methods to accurately measure the strength of this detonation and its usage are being considered and used from various viewpoints. We measure this detonation quantitatively by the detonation counter. This is done in order to bring out optimum performance of the engine, specifically the spots, carburetor settings, and ignition timing. Where adjustments must be made and it is useful as a tool for judging, conducting, and setting adjustment directions and volume quickly and accurately.     

城市混合动力客车关键技术研究

随着能源危机与污染问题的日益严峻,混合动力汽车受到越来越多的关注,并且取得了飞速的发展.本文针对混合动力客车的发展,对限制混合动力客车发展的关键技术进行了研究,指出了现存的问题并作出了总结.