共轨喷油器在车喷油量控制自学习方法

为了精确控制喷油器老化后的在车喷油量,分析了共轨喷油器老化试验前后的小油量喷射特性,提出了小油量自学习修正的方法。当发动机处于倒拖工况时,在不同的轨压下,通过主动小脉宽喷射测得特定缸角加速度与其他几缸角加速度平均值的比值,研究得到发动机小油量燃烧后角加速度变化规律,并据此设计喷油量控制自学习算法。实车试验与台架试验表明,在无需增加额外传感器的情况下,小油量自学习修正算法能精确控制老化喷油器的小油量,明显改善老化喷油器小油量喷射的一致性和稳定性,满足发动机在全寿命期间的性能要求。     

提高共轨喷油器工作效率研究

根据电磁阀式共轨喷油器工作特点,研究了提高大流量电磁阀式共轨喷油器工作效率的技术途径。以喷孔前的压力为实际喷油压力,其与供油压力的比为共轨喷油器的有效喷油压力效率;以喷油量与喷油量和总回油量之和的比为共轨喷油器的有效喷油量效率。结果表明：喷油器有效喷油压力效率与有效喷油量效率相互影响;采用异型结构喷油嘴偶件可以有效提高喷油器工作效率;喷油器与燃油轨间高压管路长度、喷油嘴偶件及其他结构参数进行综合匹配,能够进一步提高喷油器工作效率。综合匹配的计算结果表明,在160 M Pa 标定压力下,最大有效喷油压力效率达到108．3％,有效喷油量效率达到96．8％。     

博世共轨系统的喷油特性对柴油机性能的影响

文章旨在对高压共轨系统喷油特性从理论和测试两方面进行深入分析,以博世第2代共轨系统CRSN2为研究对象,应用INCA5.4标定软件,对系统的喷油特性,进行了综合完整的在线标定实验。测试数据明显地反映了不同的喷油特性对于柴油机动力性、经济性及排放等各方面性能的影响。同时,在理论上从燃油喷射和缸内燃烧的角度详尽地分析了喷油特性对柴油机性能影响的原因,进一步验证了测试结果。     

Adaptation Strategy for Exhaust Gas Recirculation and Common Rail Pressure to Improve Transient Torque Response in Diesel Engines

Fuel injection limitation algorithms are widely used to reduce particulate matter (PM) emissions under transient states in diesel engines. However, the limited injection quantity leads to a decrease in the engine torque response under transient states. To overcome this issue, this study proposes an adaptation strategy for exhaust gas recirculation (EGR) and common rail pressure combined with a fuel injection limitation algorithm. The proposed control algorithm consists of three parts: fuel injection limitation, EGR adaptation, and rail pressure adaptation. The fuel injection quantity is limited by adjusting the exhaust burned gas rate, which is predicted based on various intake air states like air mass flow and EGR mass flow. The control algorithm for EGR and rail pressure was designed to manipulate the set-points of the EGR and rail pressure when the fuel injection limitation is activated. The EGR controller decreases the EGR gas flow rate to rapidly supply fresh air under transient states. The rail pressure controller increases the rail pressure set-point to generate a well-mixed air-fuel mixture, resulting in an enhancement in engine torque under transient states. The proposed adaptation strategy was validated through engine experiments. These experiments showed that PM emissions were reduced by up to 11.2 %, and the engine torque was enhanced by 5.4 % under transient states compared to the injection limitation strategy without adaptation.     

GD-1高压共轨电控柴油机起动控制的试验研究

与机械式供油系统相比,高压共轨电控系统在起动时可迅速建立起较高的油压、灵活地调节喷油量和喷射提前角。基于GD—1高压共轨电控系统,采取对喷油量、喷油压力和喷射正时等主要参数的调节与控制,做了电控共轨柴油机起动的试验研究。试验结果表明,该系统能有效改善柴油机起动性能。     

GD-1高压共轨式电控柴油机急减速控制策略的研究

柴油机急减速的控制是柴油机过渡工况控制中的一个重要方面。基于GD—1 高压共轨电控车用柴油机,设计了急减速过程中喷油量与喷油压力的控制策略。实机试验表明,该控制策略的应用保证了柴油机急减速时转速与喷油压力的平稳过渡,减少了燃油消耗与废气排放,改善了车用柴油机的调速性能。     

Effect of injector parameters on the injection quantity of common rail injection system for diesel engines

In this paper, the bond graph model of common rail injector was proposed in consideration of the effects of variable liquid capacitance and fuel physical property on the injection characteristics of the injector. State equations were derived based on the model, which were numerically solved by programming in Matlab. Comparisons between the simulation results and the experimental data show that the numerical model can effectively predict the injection quantity of the system. Effect of variation of 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 on fuel injection quantity had been analyzed. The influence rules of various parameters on the fuel injection quantity had been established. The experiments were conducted using face centered central composite design. A second order polynomial response surface model had been developed for predicting fuel injection quantity, as a function of the independent variables. Analysis of variation was used to determine the significance interactions which primarily affect the fuel injection quantity. It had been concluded that six interaction factors including delivery chamber diameter with nozzle hole diameter, needle seat semi-angle with needle cone semi-angle, needle seat semi-angle with nozzle hole diameter, needle cone semi-angle with nozzle hole diameter, nozzle hole diameter with inlet orifice diameter, and nozzle hole diameter with outlet orifice diameter have significant effect on the fuel injection quantity of the system.     

高压共轨柴油机喷射控制策略研究

针对ECD-U2高压共轨系统,基于自主开发的电控单元,综合考虑柴油机的各种运行工况,利用软件编程设计了具体的共轨柴油机喷射控制策略,实现了稳定控制喷油压力和精确控制喷油量、喷油定时的目标,同时满足了柴油机快速起动和平稳运转的要求。台架试验验证了控制策略的可行性和可靠性,控制效果达到了预期要求。     

新型共轨蓄压式电控燃油系统及32位ECU

本文介绍了一种新型共轨蓄压、喷油规律可调式电控柴油喷射系统，该系统成功实现了高压喷射以及喷油压力、喷油量和喷油定量的灵活控制，并具有预喷射和快速停油功能，同时还具有调整喷油速率的能力。通过对中压供油系统的优化设计，实现了优良的共轨油压调节特性。为了适应未来高性能车用柴油机管理系统的需要，首次采用32位单片机，开发一种功能完善的ECU，该ECU不仅能实现对电控然油系统的完善控制，而且还具有对增压器、EGR等的控制能力。     

高压共轨系统预喷控制策略研究

柴油机高压共轨燃油喷射系统可实现预喷、主喷和后喷的多次喷射,达到燃烧柔和效果,有效地降低燃烧噪声,减少排放,是世界内燃机行业公认的未来柴油机燃油系统的发展方向。在预喷机理分析的基础之上,提出了高压共轨燃油喷射系统预喷的控制策略,解决了预喷控制中有关喷射协调、预喷油量、喷射起始时刻、喷油器作用时间和预喷释放等问题。     

高压共轨燃油系统后喷射控制研究

根据柴油机后喷射作用机理,以有效降低燃烧噪声、减少排放为目的,分析设计高压共轨燃油喷射系统后喷射控制策略,解决后喷射控制中有关喷射协调、后喷射量、喷射起始时刻、喷射器作用时间和喷射释放以及相关参数修正等问题。     

温度对共轨柴油机起动性能的影响

以Bosch第2代高压共轨燃油喷射系统为基础,建立了高压共轨试验测控系统.研究了进气温度和冷却液温度对高压共轨柴油机起动时间和排放性能的影响规律.试验结果表明,在不同起动油量和不同主喷油提前角条件下,进气预热有利于缩短起动时间、降低排放;在起动时间一冷却液温度曲线和HC排放-冷却液温度曲线上均存在最佳冷却液温度点,该点的起动性能最好.     

二甲醇(DME)发动机共轨燃料系统的试验研究

针对二甲醚燃料饱和蒸气压高、黏度低、易与空气形成混合气等特性,开发了低压共轨燃油系统。主要进行了系统的总体设计、电子控制单元(ECU)的软硬件开发和在油泵台架上的试验。试验结果表明,在新开发系统的驱动下,喷油器启合及时,喷射有力,雾化效果好;并获取供油量的MAP图,实现了对喷油量和喷油定时的外触发、外同步的反馈控制。     

共轨喷射系统参数对柴油机性能影响的模拟计算

通过应用AVL公司先进的发动机模拟计算软件BOOST建立了电控D6114ZB发动机的仿真计算模型并进行试验验证;应用MCC燃烧模型,分析了在标定工况相同喷油量和喷油提前角下不同的喷油规律对发动机性能的影响;给出了共轨压力和喷油规律对发动机性能和排放等的影响规律。     

共轨蓄压式电控喷油系统的喷油正时研究

介绍了共轨蓄压式电控喷油系统的工作原理。共轨蓄压式电控喷油系统喷油正时的控制采用开环控制方案，喷油正时的控制精度主要取决于喷油延迟时间的准确度，而喷油延迟时间主要受共轨油压和发动机转速的影响。具体分析了通过优化喷油延迟角MAP图来实现共轨蓄压式电控喷油系统喷油正时精确控制的方法。     

4JB1高压共轨柴油机开发研究

设计了4JB1柴油机共轨化的总体匹配方案和共轨柴油机的喷油量、共轨压力、喷射定时、预喷射等模块的匹配控制策略,分析了工况点使用频度对标定匹配中MAP步长和维数的影响。研究结果表明,采用变步长标定优化MAP,有效地提高了匹配效率,匹配后的发动机达到欧Ⅲ排放水平。     

电控共轨式喷射系统喷油过程的试验研究

叙述了柴油机电控共轨式喷射系统喷油过程的试验装置及原理，实测了HEUI—A液压增压式喷油器的喷油规律，并对共轨压力和喷油脉宽与喷油量、预喷射和喷油率之间的依存关系进行了综合分析。     

一种新型共轨喷油器仿真研究

针对发动机对"先缓后急"喷油规律的需求,研究了一种双控制腔进油量孔的新型共轨喷油器。基于AMESim平台建立了喷油器模型,并应用EFS测试数据进行了模型校准。结果表明:与常规共轨喷油器相比,新型共轨喷油器针阀关闭速度提高了2倍,控制腔进油量孔流通面积减少了50%以上,更容易得到"先缓后急"的靴形喷油规律;减小控制腔容积可以提高喷油响应速度,增加滑阀弹簧预紧力可以提高滑阀恢复速度,以上措施能够提高新型喷油器的多次喷射能力,满足不同发动机性能需求;受滑阀副油道的作用,新型共轨喷油器在单结构参数、单次喷射条件下,喷油一致性受加工误差影响系数降低。     

共轨柴油机启动控制研究

在自主研制的基于MPC 555的32位电控单元基础上,将柴油机的启动过程分为启动初期、启动加速期、启动过渡期和转速闭环控制期4个阶段来分别控制。根据各个阶段的特点来优化启动油量、轨压和喷油提前角等参数,控制更为精细。在一台4缸共轨柴油机上进行了启动参数优化试验,试验结果表明:优化后的柴油机启动响应快、平滑性好、转速超调小。     

Experimental studies on low pressure semi-direct fuel injection in a two stroke spark ignition engine

In this work a two-stroke scooter engine was modified to work with semi-direct injection of gasoline at a pressure of 8 bar from an injector in the cylinder barrel pointed toward the cylinder head. The influence of injection timing, injection pressure, spark plug location and air-fuel ratio, on performance, emissions and combustion characteristics has been investigated. In addition, a comparison has been made with manifold injection of gasoline on the same engine at a given speed and various outputs. A significant reduction in HC emissions and fuel consumption with no adverse effects on NOx emissions and combustion stability was observed. A small drop in power and increase in CO emission were observed disadvantages of the new injection system. Injection timing was found to be the most important factor and a balance between reduction in shortcircuited fuel by late injection, and time for mixture preparation by advancing the injection, was found to be essential.