摩托车点火线圈参数选取及其磁性材料分析

本文分析了摩托车点火线圈的初级回路,给出了初级和次级匝数的选取原则,并分析了不同导磁材料对点火系统性能的影响,为进一步提高点火线圈可靠性及降低成本提供了理论论据。     

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.     

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。     

某汽油发动机点火线圈开裂问题解析

点火线圈由初级线圈、次级线圈、磁铁、铁芯及绝缘壳体等零件组成,汽油发动机利用点火线圈将低压电转变为高压电,传递给火花塞产生电火花点燃缸内混合气,从而实现电能到热能的转换.基于其产生高压电的特殊性,点火线圈表面开裂、内部击穿为点火线圈常见故障现象.点火线圈出现故障后,无高压电产生或高压电不能完全传递至火花塞,引起动力缺失...     

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。     

对现代点火系统的一些要求

点火装置的改进是现代汽车发动机发展的结果(如它们的压缩比和曲轴转速的提高,工作混合气的稀薄化),它要求进一步提高点火系统的主要参数,如二次电压、火花放电的能量和持续时间。但是在传统的蓄电池点火系统中,这些参数提高的可能性受到断电机构触点工作能力的限制。在用半导体开关代替触点时,点火线圈初级回路的功率稍有增加,但是并不能大幅度提高火花放电的能量,因为曲轴转速提高时,为点火线圈初级绕组积累能量所必须的时间不足。只是在为电子系统制成了随曲轴转速的变化自动调节储能周期的电子装置之后,这一限制才得以消除。因此,我们认为,这就是对于现代点火系统输出参数的要求所提出的一个新课题。     

一种新的点火系统

点火系统的任务是在正确的时刻内点燃混合气。在今天其任务比以往更艰巨,因为工业上为了满足对废气污染及经济性的要求,需要点燃接近于可点火极限的混合气。许多早期的电池及磁电机点火系统采用了“电铃”线圈,它给火花塞提供了持续的一系列火花,其时间如初级电路的工作时间一样长。福特公司对其 T 型发动机用一低压磁电机通过装于凸轮轴前端的旋转定时器对四个气缸的每一缸由单独的振荡器线圈供电(见下图)。     

摩托车点火系统初级回路参数的优化在高能点火中的应用

本文分析了摩托车点火系统的初级回路，给出了初级能量与初级回路的各种参数的关系式，为精确控制点火能量及其可靠性提供了理论依据。     

宝来1.8T轿车点火线圈故障检测

一汽大众宝来1.8T轿车点火系统采用的是独立式点火线圈,主要介绍了独立点火线圈故障诊断方法及检修实例。     

降低某款发动机点火线圈市场故障率

面对汽车行业的激烈竞争,消费者不仅对汽车外观越来越挑剔,对性能及质量要求也越来越高。点火线圈作为发动机点火系统的重要零件,在市场上出现抖动和加速不良的问题,会严重影响车辆性能及用户观感质量,最终影响整个汽车品牌的价值。介绍了某款发动机点火线圈存在抖动和加速无力问题进行改善的过程。通过点火线圈故障原因解析识别,从设计和制造方面进行全面分析,制定相应的整改措施,来降低点火线圈的市场故障率。     

多次点火提高LPG发动机点火可靠性的研究

以液化石油气（1iquefied petroleum gas）为燃料的发动机对点火系统的要求较普通汽油发动机高,由于其可能存在失火使LPG发动机的怠速稳定性不佳。对应用多次点火方式提高LPG发动机的点火可靠性进行了试验研究。试验设计了通过ECU控制点火提前角的多次点火系统,并通过怠速稳定性间接验证了多次点火对点火可靠性的影响。试验结果表明：多次点火有助于提高点火可靠性,特别在点火提前角过大或过小、空燃比偏离最佳点火比例时。     

点火方式对汽油机燃烧过程的影响

通过基本结构的微小变动,将单火花塞点火(single spark ignition,SSI)改造成双火花塞点火(dual spark ignition,DSI),运用三维仿真软件AVL FIRE模拟仿真,并通过试验验证。再对单火花塞点火、双火花塞同步点火(dual synchronous spark ignition,DSSI)、异步点火(dual asynchronous spark ignition,DASI)3种不同的点火方式进行对比。结果表明:在6500 r/min转速全负荷状态下,空气过量系数为1.00而其他参数调整为最佳时,单火花塞的最佳点火提前角为29°,在空气过量系数为1.15的最佳参数下,双火花塞同步点火的最佳点火提前角为22°,双火花塞异步点火的最佳点火提前角为22°和24°。其中,发动机综合性能在双火花塞异步点火条件下表现最好:相对于单火花塞点火指示功提升8.49%;相对于同步点火,可将最高燃烧压力和压缩负功减小,指示功提升3.60%;同时改善了排放性。上述研究中发动机均控制在未发生爆震情况下。     

Numerical study of ignition mechanism of n-heptane direct injection compression-ignition engine

A detailed chemical dynamical mechanism of oxidation of n-heptane was implemented into kiva-3 code to study the ignition mechanism of a high-temperature, high-pressure, three-dimensional-space, transient turbulent, non-homogeneous, mono-component fuel in the engine. By testing the quantity of the heat released by the chemical reaction within the cylinder cell, the elementary reaction showing an obvious increase in the cell temperature was defined as ignition reaction and the corresponding cell as ignition position. The main pathway of the ignition reaction was studied by using the reverse deducing method. The result shows that the ignition in the engine can be divided into low-temperature ignition and high-temperature ignition, both of which follow the same rule in releasing heat, called the impulse heat releasing feature. Low-temperature ignition reaction, whose ignition reaction is c5h9o1-4=ch3cho+c3h5-a, follows the oxidation mechanism, while high-temperature ignition reaction, whose ignition reaction is c2h3o1-2=ch3co, follows the decomposition mechanism. No matter which ignition it is in, the chemical reaction that restrains the ignition reaction from lasting is the deoxidization reaction of alkylperoxy radicals.     

Numerical study of ignition mechanism of n-heptane direct injection compression-ignition engine

A detailed chemical dynamical mechanism of oxidation of n-heptane was implemented into kiva-3 code to study the ignition mechanism of a high-temperature, high-pressure, three-dimensional-space, transient turbulent, non-homogeneous, mono-component fuel in the engine. By testing the quantity of the heat released by the chemical reaction within the cylinder cell, the elementary reaction showing an obvious increase in the cell temperature was defined as ignition reaction and the corresponding cell as ignition position. The main pathway of the ignition reaction was studied by using the reverse deducing method. The result shows that the ignition in the engine can be divided into low-temperature ignition and high-temperature ignition, both of which follow the same rule in releasing heat, called the impulse heat releasing feature. Low-temperature ignition reaction, whose ignition reaction is c5h9o1-4 = ch3cho + c3h5-a, follows the oxidation mechanism, while high-temperature ignition reaction, whose ignition reaction is c2h3o1-2 = ch3co, follows the decomposition mechanism. No matter which ignition it is in, the chemical reaction that restrains the ignition reaction from lasting is the deoxidization reaction of alkylperoxy radicals.     

A coupling study of ignition position on fuel-air mixing and diffusion of a linear hydrogen engine

Linear hydrogen engine (LHE) is a new technology of hydrogen energy utilization due to its flexible compression ratio coupling with ignition, fuel-air mixing, and combustion to optimize thermal efficiency. Fuel-air mixing in LHE is expected to be promoted by using ignition, which differs with conventional engine. This paper develops a full-cycle model which couples with dynamics, hydrogen-air mixing and combustion to describe the effect of ignition position, meanwhile a loop iterative calculation method is proposed to solve the coupling model for hydrogen-air mixing predication. The results show that ignition position variation can cause the piston trajectory to change significantly, and the higher equivalent speed is obtained in the medium ignition position. Besides, the higher equivalent speed in the injection stage is conducive to the diffusion of hydrogen, but the higher equivalent speed is not conducive to diffusion and mixing in the diffusion stage. More importantly, the equivalence ratio distribution at the ignition position is more uniform for the later ignition position due to the longer mixing stroke, and the mixture uniformity index at the ignition position is inversely proportional to the advance of the ignition position. Therefore, the late ignition is recommended to obtain a uniform hydrogen mixture.     

大颗粒碳／炭着火规律的研究

本文研究了大颗粒碳／炭的着火过程，通过实验和数值模拟发现，大颗粒碳／炭的着火与小颗粒的不同，它的温升历程不存在突跃现象，因此也就不存在ｄ＾２Ｔ／ｄｔ＾２＝０的着火特征点。为此，本文针对大颗粒碳／炭着火过程的特点，提出了一个新的着火判据，据此建立了大颗粒碳／炭着火模型，导出了与小颗粒碳／炭相同形式的着火表达式。实验验证了在小颗粒模型下推导出的着火温度与煤质之间的通用关系仍适用于大颗粒碳／炭的着火。     

A review of spray ignition phenomena: Present status and future research

Theoretical and experimental studies dealing with the spray ignition phenomena are reviewed. Two major topics covered are external-source ignition of liquid fuel sprays and spontaneous spray ignition. Experimental and theoretical investigations of external-source ignition of sprays employing different configurations are discussed first. Three major topics included here are: (i) ignition of quiescent and flowing fuel sprays; (ii) ignition of monodisperse and polydisperse sprays; and (iii) ignition of single-component and multicomponent fuel sprays. Then, experimental studies of autoignition of sprays employing constant-volume enclosures, injection in a uniform air flow, and shock tube techniques, are discussed. Theoretical investigations dealing with spray autoignition phenomena range from phenomenological models to one-dimensional numerical models using global one-step as well as detailed multistep chemistry, and to multidimensional simulations with reduced mechanisms. These models are also discussed in the review. Finally, some advanced topics which are common to both external-source ignition and spontaneous ignition are identified and discussed. An attempt is made to provide a common link between the three dominant ignition modes in sprays, namely individual droplet ignition, droplet cluster ignition, and spray ignition. In a similar manner, common features of external-source ignition and spontaneous ignition of sprays are identified. A general spray ignition model along with important numerical and physical issues are presented. The effect of pressure on spray ignition processes is also discussed. Potential topics for further research are suggested.     

Transient behaviors of ignition of premixed stagnation-point flows with catalytic reactions

Transient ignition process of premixed stagnation-point flows over a catalytic surface of a solid plate with a finite thickness is investigated numerically in this work. The results reveal that the thermal runaway criterion instead of the zero-gradient criterion is preferred for the problem of interest. Depending on system parameters, both the ignition delay and the critical rate of catalytic reactions at ignition are either conductively or catalytically controlled. The effects of catalytic reactions on ignition are positive and negative for catalytically and conductively controlled ignition mechanisms, respectively. According to these two ignition mechanisms, the qualitative and quantitative results of the ignition delay and the critical rate of catalytic reactions at ignition are systematically analyzed. In particular, the minimum ignition delay and the C-shaped ignition curve are discussed.     

氮气稀释气对天然气着火特性的影响

为获得氮气稀释气对天然气着火特性的影响规律,对不同当量比、初始压力、初始温度以及氮气稀释系数下天然气的着火延迟时间进行了试验测试与数值计算,并分析了氮气稀释气对其着火特性的影响机理。结果表明,随初始温度的变化天然气着火延迟时间呈线性变化趋势;天然气的着火延迟时间随初始温度或初始压力的升高逐渐缩短,且受当量比的影响不明显;随着氮气稀释系数的增加,天然气的着火延迟时间逐渐延长,且促进天然气着火的关键反应步,■的敏感性系数将大幅度下降。     

单颗粒燃料滴在高温氧化环境中着火规律的研究

本文在前人对单个油滴着火规律研究的基础上，通过分析着火过程中油滴周围气相温度场、浓度场的特点，提出了油滴着火的分区反应模型，得到了直观的着火条件解析表达式。在此基础上，预报的临界着火温度与环境氧浓度的关系，与实验结果符合得很好。另外，用这个着火条件结合油滴加热过程的分析计算，得到了着火延迟时间与各因素的关系，与实验结果对比，证明了这种分区近似法是一种预报、分析油滴着火过程的较简单、准确的方法。