基于电流反馈控制的天然气喷射阀高低压 分时驱动电路的设计和试验

在分析和测试单电源天然气喷射阀驱动控制电路性能不足的基础上,提出了一种基于电流反馈高低压分时驱动天然气喷射阀的电路方案,并利用UC3843开关电源芯片实现大功率升压斩波(Boost)型电源模块的设计。基于天然气喷射阀供气量测试台架系统,测试天然气喷射阀在发动机不同转速和喷射脉宽下两种控制方案的供气量,试验结果表明电流反馈高低压分时驱动天然气喷射阀的流量平均相比单电源驱动提升了23.73%,流量线性度得到明显提高。     

点火系统能量的测量和模拟及其对发动机性能的影响

本文研宄单缸汽油机点火参数对循环变动和油耗率的影响。测量了点火线圈高、低压两端的点火能量,并用无源元件的简单模型预测了性能。通过改变火花塞间隙和线圈通电时间来改变火花能量。用专用的热量计测量了火花能量,以寻求发动机性能与火花能量的关系。试验工况是低速、部分负荷并燃用稀混合气,因为该工况下的循环变动量较大。试验证明了大间隙火花塞的转换效率较高,且发现了火花塞间隙比火花能量对决定发动机的性能更重要。     

脉冲爆震发动机起爆点火系统方案研究

在分析爆震波的基本理论、脉冲爆震发动机(PDE)的工作原理及对现有航空发动机和汽车点火系统进行研究的基础上，根据PDE对起爆系统点火能量和火花频率可调的要求，提出了以晶闸管为开关控制元件和电容储能的半导体高能点火系统方案．设计的倍压整流、半波整流和直流供电的脉冲爆震发动机起爆点火系统实现了点火能量和火花放电频率的控制．电路模拟仿真表明，设计的起爆点火系统可满足脉冲爆震发动机的要求．     

压缩天然气发动机点火驱动的设计与研究

介绍了基于电控调压器技术的压缩天然气发动机电控系统.为了实现点火正时和点火能量的精确控制,设计了单缸高能点火驱动系统.基于电路仿真的方法,采用智能IGBT元件简化了点火驱动硬件电路设计.基于32位微控制器的TPU时间处理单元,可以精确实现点火正时的控制、点火提前角的控制及点火能量的控制,软件设计了点火正时和能量的修正方法.另外设计了用点火提前角进行调速的方法.开发的CNG发动机ECU及相应的点火驱动模块,已经成功应用于CNG发动机台架试验.试验结果表明:点火驱动硬件工作正常可靠,可以精确控制点火正时和点火能量,通过调整点火提前角可以实现怠速中调速的效果.     

数字式光伏阵列模拟器的研究

基于当前各种主流数字式光伏阵列模拟器的优缺点进行比较分析,提出一种新的拓扑结构:单相PWM整流器加电流可逆型斩波电路,整个模拟器的功率开关器件仅需一个IPM模块,结构紧凑。PWM整流器取代二极管整流电路,可降低电网的谐波污染;电流可逆型斩波电路取代Buck电路或桥式变流电路,可克服后者无法空载运行、结构复杂的缺点。对于电流可逆型斩波电路,在传统的电流环比例积分调节器基础上,提出一种基于负载电压前馈的电流环比例积分调节器,提高系统的快速性;对模拟器的数学模型和传递函数进行详细分析,定量给出调节器的参数整定方法。3kW光伏模拟器样机的实验结果验证了提出的主电路、控制算法的有效性和稳定性。     

火花点火天然气发动机起动阶段HC排放特性研究

为降低天然气发动机起动阶段的HC排放,在一台6缸火花点火天然气发动机上进行了起动试验研究。控制起动阶段的喷射脉宽和点火提前角,采集起动后1min内的转速和排放数据。试验结果表明:在一定范围内,HC排放随喷射脉宽和点火提前角的增加而增加。为保证顺利起动并有较低的HC排放,起动初始阶段应采用较大的喷射脉宽和较大的点火提前角,而转速稳定后采用逐渐减小的喷射脉宽和点火提前角。     

基于BOOST变换器的小型风力机并网逆变控制系统设计

概述了基于BOOST变换器的小型风力机并网逆变控制系统设计方案。系统由一个H桥并网逆变器和一个BOOST升压斩波电路组成。对并网逆变器采用电流内环和电压外环双环控制,以取得网侧电流的快速跟随性和直流侧电压的抗扰性;对BOOST斩波电路进行功率控制,实现风力发电机的最大功率跟踪。系统采用了根轨迹图解法进行控制器参数设计,并取得了较好的动态控制性能。最后,以1.5kW并网逆变器的试验结果验证了设计的正确性。     

JL465Q5发动机点火线圈特性研究

针对JL465Q5发动机,以ATmega8单片机为核心,成功开发出一套应用天然气的电控点火系统,该系统已在发动机台架试验中成功应用。为了优化发动机的燃烧过程,对点火能量进行了测试。试验采用改变点火线圈的初级回路的闭合时间,测试点火线圈的初级断开电流、次级输出电压和电流,计算出点火线圈的初级储能、次级输出能量以及点火线圈的能量转化效率。试验结果表明,点火线圈的初级储能在闭合时间为6ms时接近饱和,继续增大闭合时间,初级线圈储能和次级输出能量都不再继续增大;随着闭合时间的增长,点火线圈的能量转化效率不断下降。     

JIA65Q5发动机点火线圈特性研究

针对JIA65Q5发动机,以ATmega8单片机为核心,成功开发出一套应用天然气的电控点火系统,该系统已在发动机台架试验中成功应用.为了优化发动机的燃烧过程,对点火能量进行了测试.试验采用改变点火线圈的初级回路的闭合时间,测试点火线圈的初级断开电流、次级输出电压和电流,计算出点火线圈的初级储能、次级输出能量以及点火线圈的能量转化效率.试验结果表明,点火线圈的初级储能在闭合时间为6ms时接近饱和,继续增大闭合时间,初级线圈储能和次级输出能量都不再继续增大;随着闭合时间的增长,点火线圈的能量转化效率不断下降.     

一种可变湍流参数的定容燃烧弹试验装置

设计了一种可变湍流参数定容燃烧弹试验装置,用于预混湍流燃烧的基础研究。该试验装置利用带有通孔的板在容弹内的快速平动来产生可控的湍流,它能方便地改变容弹内充量的湍流参数（包括湍流强度和湍流标尺）、热力参数（包括燃空比、残余废气系数和压力）以及点火参数（火花塞位置、电极间隙与点火能量）。介绍了该试验装置的定容燃烧弹、湍流发生系统、混合气配制系统、点火系统、燃烧压力测量系统、纹影与高速摄影系统以及时序控制系统等子系统的设计原理、结果及其特点。     

Experimental study of ignition of magnesium powder by electrostatic discharge

Ignition of non-aerosolized powders by electrostatic discharge (ESD) is investigated. A spherical powder of Mg, for which thermal ignition kinetics was described in the literature, was used in experiments. The experimental setup was built based on a commercially available apparatus for ESD ignition sensitivity testing. Additional diagnostics enabled measurements of electrical current, voltage, and spark and ignited powder emission in real time. The spark duration was of the order of a few μs. The spark current and voltage were always observed to have significant AC components. The electrical impedance of the spark discharge was determined experimentally using the recorded current traces and assuming that the spark and powder could be represented as a series LRC circuit. The optical emission was filtered to separate the signals produced by the spark plasma and by the heated and igniting powder. The radiation signal produced by the igniting powder was always delayed after the spark. The delay time decreased from about 3.5 to 0.5 ms as the spark energy increased from 10 to 60 mJ; the delay remained nearly constant when the spark energy continued to increase to over 100 mJ. For experiments where the powder volume decreased or where binder was introduced delay times were reduced. For the powder with a small amount of binder, the ignition delay continued to decrease for spark energies exceeding 60 mJ. Interpretation of the obtained experimental data suggests that the ignition is primarily due to direct Joule heating of the powder by the spark current.     

基于南方摩托157FMI汽油发动机的点火提前角调节装置的研制

基于南方摩托157FMI汽油发动机，现研究开发了一种以单片机为核心的、能控制发动机点火提前角的系统。该系统既能实现发动机点火提前角的计算与调节，还可以在发动机自主运行与该系统控制运行之间进行切换。该系统配合火花塞离子电流检测装置，可以实现对不同火花塞热值进行测试比较的目的。     

Statistical analysis of electrostatic spark ignition of lean H2/O2/Ar mixtures

The concept of minimum ignition energy (MIE) has traditionally formed the basis for studying ignition hazards of fuels. However, the viewpoint of ignition as a statistical phenomenon appears to be more consistent with the inherent variability in engineering test data. We have developed a very low-energy capacitive spark ignition system to produce short sparks with fixed lengths of 1-2 mm, and the ignition system is used to perform spark ignition tests using a range of spark energies in lean hydrogen-oxygen-argon test mixtures used in aviation safety testing. The test results are analyzed using statistical tools to obtain probability distributions for ignition versus spark energy. A second low-energy spark ignition system was also developed to generate longer sparks with varying lengths up to 10 mm. A second set of ignition tests is performed in one of the test mixtures using a range of spark energies and spark lengths. The results are analyzed to obtain a probability distribution for ignition versus the spark energy per unit spark length. Preliminary results show that a single threshold MIE value does not exist, but rather that ignition is statistical in nature and highly dependent on mixture composition and spark length.     

磁电机双电容能量叠加点火电路的设计与研究

基于摩托车上广泛采用的磁电机CDI(电容放电式)点火系统,针对现有磁电机CDI点火电路的火花放电持续时间短,电容放电能量低等缺点,结合多电容能量叠加点火系统可以提高点火能量,延长火花放电时间的优点,设计了一种磁电机双电容能量叠加点火电路,并在MATLAB中进行了仿真研究。     

微机控制汽油机点火系以提高点火能量

本文介绍了一种利用微型计算机控制汽油机点火系以提高点火能量的方法,用微机控制初级电路导通的时间,同时减小初级回路的电阻,使得断开电流增大而又不致烧坏点火线圈,提高了点火能量以及最大次级电压,从而可增大火花塞间隙,试验表明用此方法可以燃烧更为稀薄的混合气,使油耗率大为下降。     

单点燃油喷射式火花点火发动机进气系统的建模

讨论单点燃油喷射式火花点火发动机的非线性动态模型，该模型可用于控制算法的火花点火式发动机开发研究。针对空燃比控制，模型建立从节气门和进气歧管两方面进行，所建模型可采用控制算法对其进行实时控制和系统仿真，模型的复杂程度足以代表一般的火花点火式发动机，模型中的参数可以通过实机测试或仿真来设置。     

点燃式发动机点火能量对火核生成和初期发展的影响

摘要本文研究了点燃式发动机点火能量对火核生成和初期发展的影响.发现增加点火时的击穿能量,可使火核的初始尺寸有效地增加,从而加快火焰的形成和初期发展,并且可以燃烧更为稀薄的混合气,而仅仅增加电容和电感放电阶段的点火能量却没有显著的效果.     

Effect of pre-chamber geometrical parameters and operating conditions on the combustion characteristics of the hydrogen-air mixtures in a pre-chamber spark ignition system

The pre-chamber spark ignition system is a promising advanced ignition system adopted for lean burn spark ignition engines as it enables stable combustion and enhances engine efficiency. The performance of the PCSI system is governed by the turbulent flame jet ejected from the pre-chamber, which is influenced by the pre-chamber geometrical parameters and the operating conditions. Hence, the current study aims to understand the effects of pre-chamber volume, nozzle hole diameter, equivalence ratio, and initial chamber pressure on the combustion and flame jet characteristics of hydrogen-air mixture in a passive PCSI system. Pre-chamber with different nozzle hole diameters (1 mm, 2 mm, 3 mm, and 4 mm) and volumes (2%, 4%, and 6% of the engine clearance volume) were selected and manufactured in-house. The experimental investigation of these pre-chamber configurations was carried out in a constant-volume combustion chamber with optical access. The flame development process was captured using a high-speed camera at a rate of 20000 fps, and the images were processed in MATLAB to obtain quantitative data. The combustion characteristics of hydrogen-air mixtures with the PCSI system improved when compared to the conventional SI system; however, the improvement was more significant for ultra-lean mixtures. Early start of combustion and shorter combustion duration were observed for PCSI – D2 and PCSI – D3 configurations, respectively and improved combustion and flame jet characteristics were also noted for these configurations. With the increase in pre-chamber volume, ignition energy associated with the flame jet increases, which reduces the combustion duration and the ignition lag.     

基于事件的电喷汽油机喷油点火时序控制策略研究

针对所研究的吉利MR479Q 4缸四冲程电控汽油机,分析了曲轴转速、凸轮轴位置等信号与喷油点火及同步过程关系,给出了曲轴位置同步、喷油时序、点火时序相应具体控制策略.在此基础上,提出了完整的基于事件的电喷汽油机喷油点火及同步协调控制方案,同步过程、喷油时序、点火时序控制均由相应事件激活,并将其应用于自行研发的EMS控制器中.台架试验结果表明:汽油机起动顺利,运行平稳,稳态及瞬态工况下喷油相位、喷油脉宽、闭合角及点火提前角等重要参数传递准确及时,喷油点火控制信号准确,控制策略切实可行.