Correlation analysis of factors influencing the electronic unit pump cycle fuel injection quantity under overall operating conditions for diesel engines

Electronic unit pump (EUP) can satisfy both diesel engine emission legislation and fuel economy by improving injection pressure and numerical control. Fluctuations in cycle fuel injection quantity (CFIQ) of EUP determine the coherence and stability of the EUP fuel injection system. The EUP simulation model is developed in the AMESim environment. The method for the simulation experiment is designed in the MODDE environment using the design of experiments method. The results of the simulation reveal the variation laws of correlation between parameters with interaction or no interaction under overall operating conditions of diesel engines. In addition, the results also show the EUP system is a complex nonlinear system. Under overall operating conditions, all the characteristic parameters, such as fuel supply pressure, cam profile velocity, control valve lift, injector opening pressure, injector needle lift, and injector flow coefficient, have significant correlation with CFIQ. The interacting first-order factors exhibit the most significant correlation with CFIQ. The self-interacting second-order factors have significant secondary correlation with CFIQ.     

电控单体泵柴油机燃油喷射控制策略

电控单体泵由电控泵喷嘴发展而来,由于在电控泵与喷油器之间加入了高压油管,使电控单元从发出喷油信号到燃油喷入汽缸的时间延迟加长.针对该特点,以及考虑到程序计算时间、电磁阀响应特性等因素对喷油正时的影响,设计了喷油正时控制策略.试验结果表明,电控单元可按喷油正时控制策略准确地、柔性地控制喷油正时和喷油量.     

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.

     

Improvement of lubrication characteristics in the reciprocating fuel pump of marine diesel engines

In this study, we apply circumferential grooves and taper shape to the plunger in order to improve the lubrication characteristics of reciprocating fuel pumps for marine diesel engines. We use the two-dimensional Reynolds equation to evaluate lubrication characteristics with variation of viscosity, clearance, groove and taper for an incompressible, unsteady state flow. Moreover, we use the equilibrium equation of moment and forces in the vertical and horizontal directions to determine the motion of the plunger. The validity of numerical model is verified through the fact that the position of wear is similar to that of minimum film thickness. We investigate the lubrication characteristics of the pump by comparing the dimensionless minimum film thickness, or film parameter. Through numerical analysis, we find that to improve the lubrication characteristics of the pump, applying both circumferential groove and taper shape to the plunger is more effective than applying just either one of them.

     

电控单体泵循环喷油量测量方法及分析

基于先进的 EFS 瞬时喷油量测量仪,采用位移法分别对电控单体泵不同转速工况进行循环喷油量的精确测量。依据循环喷油量及喷油压力的试验数据,得到了电控单体泵喷油量不一致性变化规律以及不同转速下的主要影响因素。分析结果表明,在最大扭矩工况,各单体泵循环喷油量不一致性最低,而启动工况和最大功率工况的不一致性较高。     

基于电喷发动机的挖掘机控制系统设计

现有的机械式发动机排放差、能耗高,采用电喷发动机作为挖掘机的动力源将提高燃油效率,开发电喷发动机的控制系统具有重要意义．在现有挖掘机控制系统的功能分析基础上,确定了基于电喷发动机的控制系统的功能原理图,分析了J1939的协议,确定了电喷发动机的主要参数的解析和控制方法,通过CoDeSys（Controlled Development System）平台设计了电喷发动机的控制系统,并进行了控制试验．试验结果表明：设计的控制系统能正确控制发动机转速和实现相关参数的测量,对挖掘机的电控节能研究具有一定的参考价值．     

Computation of pressure fluctuation frequency in electronic unit pump for diesel engine

Pressure variations inside a fuel injection system can lead to fluctuations in injected fuel quantity during injections and therefore can directly impact the stability and performance coherence of the fuel injection system and the engine it matched. Concepts of hydraulic capacitance and hydraulic inductance are introduced into fuel injection system by referencing LC oscillator electric circuit. A LC undamped hydraulic mathematical model is developed based on the structural parameters of the electronic unit pump (EUP). Pressure fluctuation frequency during injection process at different operating conditions of the EUP is computed by the LC undamped model. It is observed that the frequencies of pressure fluctuations tend to increase with the fuel injection process. Pressure curves and pressure fluctuation frequencies obtained by experiments at different operating conditions validated the results predicted by the LC undamped mathematical model.     

A tribological investigation of lubricant effects on bearing friction and fuel economy for passenger car engines and heavy duty diesel engines

Rising fuel costs and the need to conserve fossil fuel have led to increased interest in the role of lubricants in improving fuel economy. Crankshaft bearings can account for up to 40% of engine friction. Lubricant formulations can provide a beneficial reduction in engine friction, thus improving fuel economy. A unique journal bearing test rig has been developed to evaluate lubricants under transient and steady‐state conditions for passenger car engines and heavy duty diesel engines. The rig can measure bearing friction over a wide temperature, speed and load range. The rig uses production components and can be operated so as to produce the bearing pressures, lambda ratio and shear rates experienced by lubricants in fired engines. The properties of a range of lubricants of varying viscometrics, including Newtonian, non‐Newtonian and fully formulated oils have been evaluated. Significant differences due to formulation have been observed. The results of the study have been compared to fuel economy data generated from fired engines with the same lubricants as those tested in the journal bearing rig. Copyright © 2006 John Wiley & Sons, Ltd.     

直喷式柴油机排放颗粒的控制措施

讨论了柴油机排放颗粒的形成机理。在此基础上 ,重点论述了直喷柴油机排放颗粒控制所取得的一系列重大成果 ,以及目前正在研究探索中的电控共轨系统和替代燃料二甲醚 DME在柴油机上的应用。     

电控单体泵燃油喷射系统耦合仿真

以某一典型的电控单体泵供油单元、可压缩高压油管以及机械式一级弹簧喷油器组成的燃油喷射系统为原型,建立了电控单体泵燃油喷射系统和喷油正时控制策略的耦合仿真模型,为多学科领域复杂系统建模仿真提供了解决方案和系统工程设计的完整平台.     

替代率对CNG柴油双燃料发动机排放性影响的研究

本文通过设计台架试验,测量以潍柴226B发动机改造的CNG柴油双燃料发动机在同一工况下,替代率分别为60%、70%、80%、90%时发动机尾气中HC、CO、NOx的排放量。通过多次试验测试,对试验数据选择分析后,讨论在不同的替代率下HC、CO、NOx的排放的变化情况。综合试验表明,HC的排放随着替代率的提高而增大,NOx、CO则随着替代率的提高而减小。     

A study on effects of recirculated exhaust gas upon wear of cylinder liner and piston in diesel engines

The effects of recirculated exhaust gas on the wear of cylinder liner and piston were experimentally investigated by a two-cylinder, four cycle, indirect injection diesel engine operating at 75% load and 1600 rpm. For the purpose of comparison between the wear rates of the two cylinders with and without EGR, the recirculated exhaust gas was sucked into one of two cylinders after the soot in exhaust emissions was removed by an intentionally designed cylinder-type scrubber equipped with 6 water injectors (A water injector has 144 nozzles of mm diameter), while only the fresh air was inhaled into the other cylinder. These experiments were carried out with the fuel injection timing fixed at 15.3° BTDC. It was found that the mean wear rate of cylinder liner with EGR was greater in the measurement positions of the second half than those of the first half, that the mean wear rate without EGR was almost uniform regardless of measurement positions, and that the wear rate of piston skirt with EGR increased a little bit, but the piston head diameter increased, rather than decreased, owing to soot adhesion and erosion wear, and especially larger with EGR.     

Dynamic performances analysis and optimization of novel high-speed electromagnetic actuator for electronic fuel injection system of diesel engine

Journal of Mechanical Science and Technology - High-speed electromagnetic actuator (HEA) is the key component of Electronic fuel injection system (EFIS) of diesel engine, its dynamic performances...     

Effect of the injection parameters on diesel spray characteristics

The characteristics of the diesel spray have affected certain aspects of engine performance, such as the power, fuel consumption, and emissions. Therefore, this study was performed to investigate the effects of various injection parameters. In order to obtain the effect of injection parameters on diesel spray characteristics, the experiment is performed by using a high temperature and pressure chamber. The behaviors of the spray are visualized by using a high speed video camera, spray angle, penetration, and various other things.     

喷油泵实验台液压系统的设计

介绍了一种喷油泵试液压式验台,该试验台采用气液增压泵将气体低压转换为液体高压,并向喷油泵提供高压油.具有体积小、配置灵活、发热少、节省能源等优点.     

喷嘴参数对柴油机喷油规律与性能的影响

采用广安博之(Hiroyasu)等准维模型,建立高原运行柴油机工作过程模型;基于一维非定常可压缩理论建立柴油机喷射系统模型,二者耦合计算高原环境喷油器主要结构参数对柴油机实际运行时的喷油规律、燃烧特性和输出性能的影响.台架试验验证了模型的可信性.结果表明:喷孔数和喷孔直径对喷油规律影响最为敏感,喷孔夹角对喷油规律影响微弱.在海拔4 000m时,针对该型柴油机,喷孔面积存在一个最优区间,在该区间给出了功率变化率和喷孔面积的关系式.在燃烧室结构和供油系统参数不变的情况下,当喷孔面积减小为原喷孔的25%～60%时,柴油机功率最大提升8.5%;油耗最大下降8.8%,排气温度下降35℃以上.但是缸内温度明显上升,NOx排放恶化.研究为通过优化喷油器参数改善高原运行柴油机燃烧和性能提供了参考.     

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.     

Development of an electrically driven diesel fuel pump for commercial vehicles using HILS

Journal of Mechanical Science and Technology - Common-rail fuel injection systems on modern diesel engines have fuel pumps that are mechanically driven by the crankshaft. The pumps actually house...     

智能型柴油机消防泵组在消防给水系统中的应用

介绍了智能型柴油机消防泵组与电动消防泵组在消防给水系统中的联动作用，阐述了柴油机消防泵组的基本工作原理。在分析其自动控制的基础上给出了自动控制的硬件线路设计和PLC程序设计。     

Numerical evaluation of the potential for fuel economy improvement due to boundary friction reduction within heavy-duty diesel engines

Advanced surface treatments have been developed by a number of research institutes as an approach to reduce friction at sliding interfaces. Laboratory tests have shown that some of these surface treatments can result in boundary friction reductions approaching an order of magnitude [1], [2] and [3]. While there are many potential applications for such surface treatments, friction reduction in internal combustion engines is of particular interest due to the apparent fuel savings potential. Ricardo, Inc. has performed simulations to estimate potential fuel economy improvements due to the application of such treatments at key interfaces within engines typical of those used in large trucks. The results show that fuel economy improvements in excess of 4% can be achieved from combined application of a surface treatment and reduction in lubricant viscosity, if the surfaces can be protected against wear.