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.     

车用柴油机电控高压喷油系统与欧Ⅲ排放标准

为了满足日益严格的排放控制法规,提高燃油喷射压力、控制喷油速率、控制喷油正时成为未来柴油机的发展趋势.详细介绍了电控单体泵喷油系统工作原理.采用此系统理论上可以达到欧Ⅲ排放标准.     

单体泵电控燃油喷射系统的研究

电控单体泵喷油系统是一种能够自由灵活调整喷油量和喷油正时、具有高喷射压力的新型燃油喷射系统。系统地分析了电控单体泵（EUP）燃油喷射系统的结构和原理，介绍了系统的工作过程和主要功能，对基于MC68376单片机的柴油机燃油喷射电控系统的组成及其功能进行了介绍。单体泵燃油系统成为大功率柴油机的理想燃油系统极具前景。     

电控单体泵柴油机起动过程控制策略研究

电控单体泵柴油机起动过程控制研究是柴油机控制的核心之一,起动控制策略的制定在保证起动成功率的同时,要有效抑制转速突变减小起动过程的磨损。在分析了环境温度、起动转速、起动喷油对起动过程影响的基础上,制定了基于Ramp控制的柴油机起动控制策略,并对控制策略进行了仿真及试验验证。     

基于PWM的柴油机共轨式电控系统

采用脉宽调制信号对二位三通高速电磁开关阀进行驱动控制，能够灵活地对喷油量、喷油正时进行控制，采用PWM控制方式对柴油机共轨式电控系统进行控制。主要分析了柴油机共轨式电控燃烧油喷射系统关键部件——高速开关电磁阀的结构、PWM控制原理，以及由电控单元所产生的脉宽调制信号控制下的高速开关电磁阀动态响应特性。     

柴油机电子控制系统(二)

这类系统的电控柱塞式喷油总成如图2a所示,喷油量和转速控制机构如图2b所示。它在传统喷油泵的机械调速器壳体内安装了线性电磁铁以取代机械调速器,在喷油泵凸轮轴的自由端安装了磁电式转速传感器(见图2a),用于检测发动机的转速;并在每个喷油分泵上增设一个可以移动的控制滑套(见图2c),用于调节喷油泵的喷油定时。电控单元根据加速踏板位置、发动机转速、涡轮增压器增压压力、冷却液温度、     

双离合器自动变速器电控单元控制策略模块化设计

针对双离合器自动变速器(DCT)电控单元控制策略研究过程缺乏系统性,采用模块化方法将DCT电控单元划分为离合器控制、同步器控制、换挡总成控制以及整车控制四大模块;分析了各个模块的主要功能、划分依据以及各模块之间的控制逻辑关系;分别对各个功能模块的建模过程及控制策略进行了阐述;在此基础上,利用Matlab/Simulink软件平台,搭建了DCT电控单元控制系统的仿真模型;进行了定油门开度下,双离合器自动变速器电控单元控制策略的仿真分析。仿真结果验证了所制定的DCT电控单元控制策略的有效性,为双离合器自动变速器产品开发提供了理论依据。     

电控直列泵─管─阀─嘴柴油喷射系统的机液特性研究

电控直列泵─管─阀─嘴（PPVI）柴油喷射系统是一种新型的电磁阀溢流控制式直列泵喷油系统,通过分析该系统内部的压力波动过程,确定电磁控制阀在高压油路中的连接方式和最佳位置,揭示该系统的喷油量、喷油定时、喷油压力及喷油速率等方面的喷射特性,通过系统结构设计、硬件调整和软件标定解决多缸机系统的油量均匀性问题,进行电控柴油机的台架试验,表明喷射特性的可控性及其对整机综合性能的改善效果。     

车用柴油机电控系统电子控制单元的开发

开发电子控制单元是车用柴油机电控系统开发的关键。针对车用柴油机可变预行程泵电控系统,进行了电子控制单元软硬件的开发。将所开发电控单元与信号采集部分、执行机构及可变预行程泵集成后,在油泵试验台上进行了系统试验,验证了电控单元的控制性能。     

电控单体泵式柴油机的建模与仿真研究

基于柴油机缸内工作过程的数学模型，在MATLAB/SIMULINK环境下建立了一个涡轮增压发动机的仿真模型，详细描述了柴油机、增压器的热力学和动力学子模型。该模型主要用于研究电控单体泵式柴油机中的各种控制参数对性能的影响，也用于调整喷油正时的控制策略。以YC6112柴油机为仿真对象，给出了典型稳态过程的仿真结果。由于大部分采用非线性模型，该系统能很好的满足动态仿真的精度要求，也解决了准线性模型大量依赖试验和经验数据的问题。     

电控单体泵系统喷射延迟特性研究

燃油喷射系统延迟特性是影响电控柴油机精确正时控制的最重要因素,在EFS油泵试验台上研究了转速、喷油量这两个因素对燃油喷射系统延迟特性的影响,利用无交互双因素方差分析法对不同转速和喷油量下的起喷及停喷延迟时间样本值进行了方差分析。分别检验了转速和喷油量对喷射以及停喷延迟时间影响的显著性。结果表明:转速对起喷及停喷延迟时间的影响都非常显著,而喷油量只对停喷时间有显著影响。利用试验和方差分析结果对延迟时间补偿脉谱的标定方案进行了改进,简化了标定工作量。     

Model-based optimization of injection strategies for SI engine gas injectors

A mathematical model for the prediction of the mass injected by a gaseous fuel solenoid injector for spark ignition (SI) engines has been realized and validated through experimental data by the authors in a recent work [1]. The gas injector has been studied with particular reference to the complex needle motion during the opening and closing phases. Such motion may significantly affect the amount of injected fuel. When the injector nozzle is fully open, the mass flow depends only on the upstream fluid pressure and temperature. This phenomenon creates a linear relationship between the injected fuel mass and the injection time (i.e. the duration of the injection pulse), thus enabling efficient control of the injected fuel mass by simply acting on the injection time. However, a part of the injector flow chart characterized by strong nonlinearities has been experimentally observed by the authors [1]. Such nonlinearities may seriously compromise the air-fuel mixture quality control and thus increase both fuel consumption and pollutant emissions (SI engine catalytic conversion systems have very low efficiency for non-stoichiometric mixtures). These nonlinearities arise by the injector outflow area variation caused by needle impacts and bounces during the transient phenomena, which occur in the opening and closing phases of the injector. In this work, the mathematical model previously developed by the authors has been employed to study and optimize two appropriate injection strategies to linearize the injector flow chart to the greatest extent. The first strategy relies on injection pulse interruption and has been originally developed by the authors, whereas the second strategy is known in the automotive engine industry as the peak and hold injection. Both injection strategies have been optimized through minimum injection energy considerations and have been compared in terms of linearization effectiveness. Efficient linearization of the injector flow chart has been achieved with both injection strategies, and a similar increase in injector operating range has been observed. The main advantage of the pulse interruption strategy lies on its ease of implementation on existing injection systems because it only requires a simple engine electronic control unit software update. Meanwhile, the peak and hold strategy reveals a substantial lack of robustness and requires expressly designed injectors and electronic components to perform the necessary voltage commutation.     

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.     

A study on the design and application of optimized solenoid for diesel unit injector

With the Environmental Protection Agency (EPA) regulating the amount of NOx, Particulate, HC and CO at all driving conditions, emission standards for diesel engines are becoming more stringent than ever. To meet future emission regulations, researchers have proposed two solutions based on injection control, the common-rail type injection system, and the unit injection system. Most researchers agree that the electronically controlled unit injector, which realizes high injection pressure and precise control of SOI (Start Of Injection) and injection quantity, has an advantage in meeting future emission regulations. In order to control the start and end of injection, each unit injector contains a time-controlled high speed solenoid valve. Thus, the fuel injection quantity is determined by the time interval between closing and opening of the solenoid valve. This study introduces a method for the design of the solenoid which is installed in the unit injector. It is shown that there are certain significant parameters to be optimized to improve solenoid performance: inductance, stroke, input voltage, coil resistance, load and switching time.     

位移传感器在电控喷油泵中的研究与应用

位移传感器是电控喷油泵闭环控制系统中的位置反馈元件，它在整个闭环回路中是一个非常关键的部分，与喷油泵喷油量相对应的齿条位置实时通过该位移传感器来检测，电子控制单元根据检测到的齿条位置，控制执行器的输出，实时调节喷油泵的喷油量。对传感器的特性进行了测试研究，并给出了传感器的激励电路和调理电路的设计思想，通过实验测试，系统达到了技术指标的要求。     

Correlating armature and needle dynamics with voltage waveforms of solenoid-actuated GDI injector

The injector voltage hump that appears near the needle closing has been used for the real-time monitoring and feedback control of fuel injection duration in modern engines. This voltage hump has been thought to result from the abrupt change in electromagnetic induction by the stoppage of needle motion but detailed electromagnetic processes and associated armature and needle dynamics during the needle closing have not been thoroughly investigated in a wide range of injection conditions, which knowledge is crucial for the delicate control of fuel injection based on the voltage hump. The current study analyzes the transient armature and needle dynamics of a solenoid-actuated gasoline direct injection injector using an X-ray phase-contrast imaging technique. Then, the results are correlated with voltage waveforms during the needle closing transient under various injection pressures, injection pulse durations, and dwell times of split injections. The time derivatives of voltage waveforms showed lower and upper peaks in order in the regime of the voltage hump. Inconsistent with conventional understandings, the lower peak timing of the voltage derivative did not match with the timing of needle closing (end of injection) but rather matched with the abrupt descent timing of the armature and needle. The inflection timing and upper peak timing of the voltage derivative matched with the timings of actual needle closing and armature closing respectively. The amplitude of the voltage hump was near linearly dependent on the needle closing speed. The needle closing speed decreased upon the decrease of injection pulse duration and injection pressure which made it difficult to detect the voltage humps in ballistic injection regimes and low injection pressures. In split injection conditions, the voltage hump of the first injection was not detectable if the dwell time was shorter than the needle closing delay, the time from the current cut-off to the actual needle closing.     

A study on the effect of operating conditions for the stability at idle

A gasoline engine with an electronically controlled fuel injection system has substantially better fuel economy and lower emissions than a carburetted engine. In general, the stability of engine operation is improved with fuel injector, but the stability of engine operation at idle is not improved compared with a carburetted gasoline engine. In addition, the increase in time that an engine is at idle due to traffic congestion has an effect on the engine stability and vehicle reliability. Therefore, in this research, we will study the influence of fuel injection timing, spark timing, dwell angle, and air-fuel ratio on engine stability at idle.