柴油发动机高压共轨喷射系统介绍

近年来柴油发动机高压喷射及其电控技术的快速发展,使柴油机在油耗、功率、扭矩和尾气排放方面显现出越来越明显的优势。国外发展趋势表明,柴油机在市场中的份额将会越来越大。通过对德国西门子公司VDO汽车零部件部门研制开发的第二代采用压电石英元件的共轨喷射系统的介绍,让读者了解到柴油共轨喷射系统的最新科技与发展动向,为国内柴油发动机技术革新与生产加工提供一定的帮助。     

德尔福高压共轨技术介绍

德尔福柴油系统的前身是卢卡斯柴油系统,在20世纪30年代开始生产机械式高压柴油泵,50年代开始生产机械式转式泵,进入90年代,开始研发电控高压共轨系统,并在2000年首次投放了高速电磁阀的轻型高压共轨系统。2008年,德尔福推出革命性的全球独创的直接控制式的压电晶体共轨系统,应用于奔驰轿车柴油机上。在德尔福高压共轨发展的过程中,经历了一系列技术变革。德尔福在2000年投放市场的高速电磁阀的共轨系统是它的第一代共轨系统,应用在轻型和中型的轿车发动机上,以及轻型中型的商用车柴油机上。从最初的高速电磁阀的共轨系统,至今已经演变为三个不同的系统,一种是用于微型柴油机上的单缸泵共轨系统,我们     

压电石英称重传感器及其在动态公路车辆称重系统中的应用

本文介绍了以石英晶体为敏感元件的压电石英称重传感器的工作原理、结构与特点;石英晶体的压电效应,压电石英晶体片的并联、串联连接方法,电荷电压计算;石英晶体片的装配要求和装配工艺;石英晶体敏感元件与电阻应变计的性能比较。分析利用多个石英晶体敏感元件组装的工字梁型动态称重传感器的结构与技术特点,及其在动态公路车辆称重系统中的应用。     

热敏传感器（二）

七、压电型热敏传感器 1.压电石英热敏传感器 压电石英晶体的弹性模量随温度变化,故其频率亦随温度变化。利用压电石英晶体的这一特性,1971年即制作了可作温度标准用的压电石英热敏传感器,     

一种压电执行器部件预紧力测试方法研究

压电执行器部件是新一代高压共轨压电喷油器中的关键部件,其封装时需要施加一定的预紧力。本文提出了一种压电执行器部件预紧力的测试方法,设计了相应的测试装置,并制定了试验流程。通过样品压电执行器部件预紧力的试验验证,表明该测试方法可以准确测量压电执行器部件预紧力大小。     

直接驱动式共轨系统可控针阀升程的驱动电路研究

针对柴油发动机喷油速率的控制问题,对喷油速率的控制方式进行了归纳总结,对直接驱动式共轨系统的特点和优势,以及直驱喷油器针阀的控制方式进行了分析,对于压电执行器的驱动电路以及充放电控制策略进行了分析,将可变电阻这一思路引入到电压反馈电路中,设计出了驱动电路的可变反馈模块,通过电控单元控制反馈电阻的选取,实现了在燃油喷射过程中对压电执行器驱动电压以及针阀升程的阶梯控制。对驱动电路进行了仿真优化设计,并利用压电执行器来对驱动电路进行了试验验证。研究结果表明,压电执行器完全充放电时间在120μs左右,喷油过程中驱动电压的变化可在100μs内实现,满足共轨系统对针阀的响应要求,所设计的驱动电路能够在燃油喷射过程中通过改变驱动电压来控制喷油速率。     

高压共轨柴油机轨压控制策略

在柴油机高压共轨燃油喷射系统中,共轨压力不仅决定了喷油压力的高低,而且是喷油计量的重要参数,其稳定性和过渡响应直接影响发动机起动、怠速、加速等性能。共轨压力的精确控制是共轨系统优于传统供油系统的重要因素,因此共轨压力的控制是高压共轨电控系统开发的一个关键环节,它是高压共轨系统与电控柴油机匹配的关键,同时对电控柴油机的批量生产起着决定性的作用。共轨压力控制策略研究柴油机在一定的工况下,要求共轨内的压力稳定在某一数值,轨压波动越小越好,这样有利于实现喷油量     

压电材料动态称重传感器的融合设计方法

针对压电薄膜传感器测量受温度影响较大、压电石英传感器价格昂贵的问题,提出将2条压电石英传感器嵌入4排压电薄膜传感器的融合设计方法,建立压电薄膜传感器的等效安装模型及温度补偿算法,利用压电石英传感器对各排压电薄膜传感器进行实时准确的温度补偿。通过MATLAB软件,在正弦波路面激励下,当车速为10～120 km/h,环境温度为0～40℃时,对1/4车辆模型进行动态称重仿真实验。结果表明,融合设计的称重误差均值控制在0. 97%以内,比4排压电薄膜传感器精度提高23倍多,比4排压电石英传感器价格降低3倍多,实现了车辆动态称重的高精度低成本检测目的,工程应用价值好。     

共轨管总成清洁度的控制

高压共轨系统是柴油机燃油系统的发展方向,共轨管总成是其核心部件之一。共轨管总成由共轨管、限流器部件、限压阀部件和压力传感器等组成,在系统中起着稳压、流量保护等关键作用。高压共轨系统的很多故障和共轨管总成直接相关,因故障种类多,成因复杂,给分析改进工作带来了很大困难。     

基于AMESim的共轨管结构分析

共轨管在共轨喷油系统中承担着建立喷油压力的任务,直接影响整个系统的性能。本文结合共轨管的结构特点和工作原理,利用AMESim软件建立合理的共轨管的仿真模型,分析了共轨管的结构对喷油压力的影响,为系统的优化设计提供了理论依据。     

柴油机高压共轨电控燃油喷射技术

介绍了柴油机高压共轨电控燃油喷射系统的特点、发展历程、结构和原理,并对三种先进的高压共轨喷射系统进行了介绍和分析,总结了三种喷射系统技术的最新发展,最后归纳并提出了高压共轨喷射系统未来的研发目标和技术发展方向。     

提高高压共轨系统高压供油泵供油效率的仿真研究

针对典型的高压共轨燃油喷射系统高压供油泵的供油过程,利用AVL公司开发的HYDSIM软件建立模型,给出高压供油泵结构参数对油泵供油效率的影响,为高压供油泵的优化设计提供理论依据.     

STRUCTURE PARAMETERS DESIGN AND PERFORMANCE TEST OF FUEL INJECTION SYSTEM

Based on the numerical simulation analysis, structure parameters of the high pressure fuel pump and common rail as well as flow limiter are designed and the GD-1 high pressure common rail fuel injection system is self-developed. Fuel injection characteristics experiment is performed on the GD-1 system. And double-factor variance analysis is applied to investigate the influence of the rail pressure and injection pulse width on the consistency of fuel injection quantity, thus to test whether the design of structure parameters is sound accordingly. The results of experiment and test show that rail pressure and injection pulse width as well as their mutual-effect have no influence on the injection quantity consistency, which proves that the structure parameters design is successful and performance of GD-1 system is sound.     

Analysis upon fuel injection quantity variation of common rail system for diesel engines

Fuel injection quantity variation of common rail system has effect on the stability and reliability of diesel engines. For purpose of investigating the influence rule and mechanism of fuel injection quantity variation caused by parameters, taking account of the influence of fuel physical properties on dynamic injection characteristics of the system, a bond graph model of common rail injector has been proposed based on bond graph methodology and the state equations of the system are obtained. Comparisons between calculated fuel injection quantities by the numerical model and experimental measurements at different rail pressures and injection pulse widths indicate that the developed model can reasonably predict the fuel injection quantity characteristic of the system. Fuel injection quantity variation characteristics caused by the parameters of common rail injector have been analyzed in entire operating conditions. The selected parameters are delivery chamber diameter, needle seat semi-angle, needle cone semi-angle, ball valve seat semi-angle, nozzle hole diameter, inlet orifice diameter and outlet orifice diameter. The variation rules of quantitative percentages are obtained by quantitative analysis upon fuel injection quantity variation influential factors. It is concluded that ball valve seat semi-angle, nozzle hole diameter, inlet orifice diameter and outlet orifice diameter have the most significant effect on fuel injection quantity variation, and the followed are delivery chamber diameter and needle seat semi-angle. In addition, needle cone semi-angle also results in the variation of fuel injection quantity, but the effect is insignificant.

     

基于RTA-OSEK开发平台的高压共轨电控喷油系统研究

将嵌入式实时操作系统引入高压共轨电控喷油系统的研究中,利用实时多任务操作系统RTA-OSEK,不仅可以提高软件的开发效率,而且可以提高软件的可靠性.通过合理的任务划分和基于优先级的抢占式调度方式,提高了CPU的利用率,确保了电控喷油实时性的要求.本文介绍了RTA-OSEK开发应用程序流程,并利用RTA-OSEK软件,建立了高压共轨电控喷油系统.     

柴油机高压共轨燃油喷射系统研究进展

高压共轨燃油喷射系统被内燃机行业公认为20世纪三大技术飞跃之一,是未来柴油机燃油喷射系统的主要发展方向。详细阐述了电控高压共轨燃油喷射系统的组成、工作原理和特点,综述了上述领域的研究现状,并提出了未来的研究目标和发展方向,以期为柴油机喷射系统的进一步发展提供思路和方法。     

An investigation on the spray characteristics of DME with variation of ambient pressure using the common rail fuel injection system

We investigated the DME spray characteristics about varied ambient pressure and fuel injection pressure using the common rail fuel injection system when the nozzle holes diameter is varied. The common rail fuel injection system and fuel cooling system were used since DME has compressibility and vaporization at atmospheric temperature. The fuel injection quantity and spray characteristics were measured. The spray was analyzed for spray shape, penetration length, and spray angle at the six nozzle holes. There are two types of injectors: 0.166 mm diameter and 0.250 mm diameter. The ambient pressure, which was based on gage pressure, was 0, 2.5, and 5 MPa. The fuel injection pressure was varied by 5 MPa from 35 to 70 MPa. By comparing with the common injector, using the converted injector it was shown that the DME injection quantity was increased 127% but it didn??t have the same low heating value. Both the common and converted injectors had symmetric spray shapes. In case of converted injector, there were asymmetrical spray shapes until 1.2 ms, but after 1.2 ms the spray shapes were symmetric. Also, the converted injector had shorter penetration length and wider spray angle than the common injector.     

船用高压共轨重油喷射伺服控制系统的动态特性研究

针对RT-flex系列二冲程低速柴油机配套燃油喷射系统存在的问题,基于液压伺服控制原理提出一种新型船用高压共轨燃油喷射伺服控制系统,该系统采用液压位置闭环系统控制高压重油喷射系统的动作。根据系统原理,研究了其数学模型,并在AEMSim软件中搭建了考虑两种流体特性的仿真模型。在给定喷射时间内得到了不同压力时的主阀芯位移曲线、喷射压力波动曲线和喷油率曲线,并计算出单次喷射时系统喷油量。仿真结果表明,在喷射时间内高压共轨重油喷射系统动作快速稳定,验证了船用高压共轨重油喷射伺服控制系统的设计是合理可行的。     

An investigation of the spray characteristics of diesel-DME blended fuel with variation of ambient pressure in a constant volume combustion chamber

We compared the spray characteristics of a typical fuel (100% diesel, DME) and diesel-DME blended fuel in a constant volume combustion chamber (CVCC). The typical fuel (100% diesel, DME) and diesel-DME blended fuel spray characteristics were investigated at various ambient pressures (pressurized nitrogen) and fuel injection pressures using a common rail fuel injection system when the fuel mixture ratio was varied. The fuel injection quantity and spray characteristics were measured including spray shape, penetration length, and spray angle.