世界能源状况及车用天然气发动机技术发展

介绍了国内外能源状况以及天然气汽车的发展现状及趋势,分析了国内外车用天然气发动机的技术应用及面临的问题,提出我国车用天然气发动机的技术发展方向。     

天然气发动机应用中的问题及发展方向

从发动机功率下降、腐蚀与早期磨损两方面分析当前天然气发动机在应用中所面临的问题及其产生原因,并提出提高天然气发动机功率和减少磨损的措施,展望未来天然气发动机的发展方向.     

天然气发动机国Ⅳ排放对策研究

为了实现天然气发动机的国Ⅳ排放,分析了天然气发动机的排放物形成机理,确定了高精度电子控制技术、优化燃烧技术和后处理技术综合应用的技术对策,并据此开发了CA4SH-N天然气发动机,匹配专门开发的YRK- 4G天然气专用催化转化器,获得了良好的降低排放效果,达到了国Ⅳ排放标准的要求.     

浅论天然气车用发动机的开发

本文对比了天然气、汽油柴油物化特性,回顾了天然气发动机燃料供给方式及天然气发动机的改装设计方法,分析了天然气发动机的燃烧特点及恢复天然气发动机功率的措施.     

浅论天然气车用发动机的开发

本文对比了天然气、汽油柴油物化特性 ,回顾了天然气发动机燃料供给方式及天然气发动机的改装设计方法 ,分析了天然气发动机的燃烧特点及恢复天然气发动机功率的措施。     

车用天然气燃料在我国的应用与发展

介绍我国石油天然气资源状况以及天然气汽车的发展现状,分析了我国天然气汽车的技术应用及面临的问题,展望了我国车用天然气发动机的发展。     

压缩天然气发动机活塞开发

总结了过去一段时间内压缩天然气发动机活塞设计开发经验,通过对压缩天然气发动机的使用情况和特点分析了天然气发动机活塞设计需要注意的问题以及相关故障的分析,通过实例介绍了天然气发动机活塞设计开发过程。本文所论述的是重型车用柴油机改造的天然气发动机活塞的开发。     

压缩天然气发动机活塞开发

总结了过去一段时间内压缩天然气发动机活塞设计开发经验,通过对压缩天然气发动机的使用情况和特点分析了天然气发动机活塞设计需要注意的问题以及相关故障的分析,通过实例介绍了天然气发动机活塞设计开发过程.本文所论述的是重型车用柴油机改造的天然气发动机活塞的开发.     

天然气发动机,新型绿色动力

天然气作为重要的能源和优质的发动机代用燃料,在21世纪将得到广泛的利用。分析了影响我国燃气汽车发展的基本因素,以及车用天然气发动机的特点和关键技术,还简要介绍了上柴客车用CNG发动机及其应用实例。     

天然气发动机掺氢燃烧的探讨

本文根据氢气、天然气和天然气掺氢燃烧的一些特性，结合世界各国对天然气掺氢在燃烧发动机上应用的研究的状况。探讨了天然气发动机掺氢燃烧应用的前途和可行性的方式。     

Experimental investigation of varying composition of HCNG on performance and combustion characteristics of a SI engine

With rapid depletion of petroleum resources, researchers are investigating alternate fuels to meet global transportation energy demand. Gaseous fuels such as compressed natural gas (CNG) and hydrogen are of special interest because of their cleaner combustion characteristics compared to liquid petroleum based fossil fuels. However both these gaseous fuels have some technical issues when they are used as stand-alone alternate fuel in conventional spark ignition (SI) engines. CNG suffers from lower energy density and narrow flammability range whereas backfiring tendency is highly pronounced in hydrogen fueled engines. Hydrogen enriched compressed natural gas (HCNG) mixtures are observed to be good alternative to these individual fuels since these mixtures do not pose the issues experienced by the constituent fuels i.e. CNG and hydrogen. In this study, experiments were conducted in a spark ignited gas engine using various compositions of HCNG mixtures having 0, 10, 20, 30, 50, 70 and 100% (v/v) hydrogen fraction. The performance and combustion characteristics of these test fuels were compared with that of baseline CNG, in order to find an optimum HCNG mixture composition for a single cylinder gas engine. Results obtained showed that 30HCNG mixture delivered superior engine performance compared to other HCNG mixtures and baseline CNG, which is in sharp contrast to 15HCNG being advocated globally.     

燃气柴油机改装方案及其排放特性研究

通过对国内外柴油机改装方案的研究,指出电控喷射双燃料柴油机适合我国现阶段柴油机的发展水平,并简要介绍了电控单元和电控喷射阀的原理,对双燃料柴油机的排放也进行了分析。     

天然气发动机的研究现状

天然气能降低发动机的有害物排放,是一种比较理想的发动机代用燃料。稀燃天然气发动机具有较高的热效率和较低的NOx排放。均质充量压缩着火(HCCI)燃烧也是提高稀燃天然气发动机热效率的方法之一,并有很低的NOx排放。本文综述了稀燃天然气发动机和HCCI天然气发动机的研究进展,尤其是燃烧室形状、点火系统、充量分层、加氢等对天然气发动机性能的影响及天然气HCCI发动机的燃烧与排放特点。     

天然气发动机神经网络控制策略及试验研究

天然气发动机本身具有低排放的特点,所以不需要由排放参数反馈修正发动机的空燃比,减少了控制的反馈系统。传统的混合器式天然气发动机无法高精度地控制发动机的空燃比,采用神经网络控制理论对天然气发动机的空燃比实施控制,使其空燃比始终保持在理论空燃比高精度的状态,提高了天然气发动机的性能。以175F天然气发动机为例,试验结果表明:采用神经网络控制的天然气发动机的性能高于混合器式天然气发动机。     

Experimental study of hydrogen enriched compressed natural gas (HCNG) engine and application of support vector machine (SVM) on prediction of engine performance at specific condition

The effect of excess air ratio (λ) and ignition advance angle (θ_ig) on the combustion and emission characteristics of hydrogen enriched compressed natural gas (HCNG) on a 6-cylinder compressed natural gas (CNG) engine has been experimental studied in an engine test bench, aiming at enriching the sophisticated calibration of HCNG fueled engine and increasing the prediction accuracy of the SVM method on automobile engines. Three different fuel blends were selected for the experiment: 0%, 20% and 40% volumetric hydrogen blend ratios. It is noted that combustion intensity varies with the excess air ratio and the ignition advance angle, so are the emissions. The optimal value of λ or θ_ig has been explored in the specific engine condition. Results show that blending hydrogen can enhance and advance the combustion and stability of CNG engine, and it also has some benefic influence on the emissions such as reducing the CO and CH₄. Meanwhile, a simulation research on forecasting the engine performance by using the support vector machine (SVM) method was conducted in detail. The torque, brake specific fuel consumption and NO_x emission have been selected to characterize the power, economic and emissions of the engine with various HCNG fuels, respectively. It can be seen that the optimal model built by the SVM method can highly describe the relationship of the engine properties and condition parameters, since the value of the complex correlation coefficient is larger than 0.97. Secondly, the prediction performance of the optimal model for torque or BSFC is much better than the case of NO_x. Besides, the optimal model built by the PSO optimization method has the best prediction accuracy, and the accuracy of the model obtained based on the training group with 20% hydrogen blend ratio is the best compared with those of others. The upshots in this article provide experimental support and theoretical basis for the adoption of HCNG fuel on internal combustion engines as well as the application of intelligent algorithmic in the engine calibration technology field.     

电控柴油/天然气双燃料发动机排放试验研究

作者研制开发了混合气双燃料发动机的电控系统，发动机起动和怠速时只燃用柴油；当转速超过某设定值，电控系统便发出指令限制柴油的喷油量，天然气就经混合器进入气缸参与燃烧，柴油只起引燃作用，通过控制天然气供给量的大小米改变负荷。结果表明，与原机相比，它显著降低了碳烟及NOx的排放。     

Experimental investigation and combustion analysis of a direct injection dual-fuel diesel–natural gas engine

A single-cylinder diesel engine has been converted into a dual-fuel engine to operate with natural gas together with a pilot injection of diesel fuel used to ignite the CNG–air charge. The CNG was injected into the intake manifold via a gas injector on purpose designed for this application. The main performance of the gas injector, such as flow coefficient, instantaneous mass flow rate, delay time between electrical signal and opening of the injector, have been characterized by testing the injector in a constant-volume optical vessel. The CNG jet structure has also been characterized by means of shadowgraphy technique.     

压缩天然气缸内直喷发动机的现状及发展趋势

天然气作为车用发动机的一种重要的"清洁燃料"日益受到人们的重视,天然气汽车在国内外均获得了较快的发展.本文简述了清洁代用燃料天然气的优缺点,以及直喷发动机的优点和目前的技术难点.最后分析了将两者相结合的天然气缸内直喷技术的特点以及国内外的研究现状和发展趋势.     

Combustion characteristics and performance of natural gas in high speed indirect injection diesel engine

In recent years, efforts have been directed towards environmentally freindly sources of alternative fuels for internal combustion engines. This paper investigates combustion characteristics and performance of natural gas in an unmodified compression ignition engine using diesel fuel pilot injection. The factors influencing knock limits in dual fuel gas engines have been identified. This report is confined to experimental work in a naturally aspirated dual gas engine and the results obtained were compared with the diesel fueled test engine. Cylinder pressure diagrams recorded indicate longer ignition delay and burning rates with an increased pressure variation.