根据化学反应动力学原理，建立了火花点火式变组分煤层气发动机CO的生成模型，该模型由碳氢燃料高温氧化生成CO以及CO在火焰中及火焰后氧化两部分组成。以MATLAB程序设计语言为应用平台，对CO的瞬时排放量进行了模拟计算，得到了发动机缸内CO的变化规律。同时，计算和分析了煤层气组分变化对CO排放的影响，并与实验结果进行了比较。研究结果证实，所建立的CO排放模型是合理的。理论和试验结果表明，提高煤层气中的甲烷浓度和发动机的负荷有利于降低发动机的CO排放量。

以火花点火式S195型煤层气发动机为基础，建立缸内燃烧过程碳化氢(HC)和氧化氮(NO)2种排放物的排放模型，以Matlab程序设计语言为平台，对HC和NO实际排放量进行仿真。计算结果表明，计算值与实测值吻合较好。研究发动机燃用变组分煤层气后HC和NO的排放特性以及煤层气组分变化对发动机HC和NO排放量的影响。提高煤层气中甲烷的体积分数有利于降低HC排放量，但不利于降低NO排放量。

Alternative fuel engines have widely been developed in the world due to the decrease of oil resources and the strictness of exhaust regulation. This paper introduces the main processes of designing the diesel engine fuelled with coal-bed gas and ignited by spark plug, and analyzes a number of problems considered in processes of designing the engine. As an example, the characteristics of a coal-bed gas engine converted from a S195 diesel engine are introduced, and the performances of the prototype engine are discussed based on the results of engine testing. And some significant conclusions were got.

There is a worldwide interest in the research of various alternative fuels for automotive engines for the purpose of reduction of CO2 and toxically harmful exhaust emissions. Coal-bed gas, the main component of which is methane, has been considered an attractive alternative fuel for combustion engines due to its abundant resources, high hydrogen-carbon ratios and very low soot formation tendency. The composition of available coal-bed gas, however, can vary considerably, and this has made its combustion stability difficult to control in conventional spark ignition engines. To overcome the problem, a combustion system with a swirl chamber connected to the main combustion chamber through an orifice has been developed for the use of coal-bed gas in spark ignition engines, and the corresponding combustion process has been studied using a developed combustion model involving flame kernel formation and flame front propagation. The combustion model includes two sub-models with the first dealing with the calculation of turbulence intensity history, and the second modeling a jet flow through the orifice of the swirl chamber. Emissions of NOX, HC and CO have been predicted using the combustion model based on an extended Zeldovich mechanism, wall quenching and incomplete oxidation simulations. The effects of various components in coal-bed gas on the engine combustion process and emissions are also investigated. Validation of the combustion model has been performed through comparing simulation data with the experimental result obtained from a relevant single cylinder research engine, and a satisfactory agreement between them has been achieved in terms of combustion parameters and exhaust emissions.

根据涡流室、主燃室中气体流动过程的质量和能量的交换关系，建立了涡流室式LPG (liquefied petrdeum gas)/柴油双燃料发动机准维燃烧模型的方程，提出了如何使两种不同性质燃料的燃烧在同一个燃烧过程中相互联系、相互作用的燃烧模型。根据模型提供的方程，对缸内燃烧过程和NOx的生成进行了模拟仿真，将其同发动机台架试验的结果进行了验证、分析和讨论。