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.

介绍了在S195柴油机上进行富氧燃烧的试验，对柴油机排放特性进行了比较与分析，目的是通过试验研究，找到在富氧条件下同时降低碳烟和NOx排放的方法。研究结果表明，增加进气氧的质量分数，碳烟排放大幅度下降,HC和CO也趋于下降，但NOx排放显著增加；推迟供油提前角，可以使NOx排放降低，但碳烟有上升趋势，HC和CO排放增加。所以，采用富氧燃烧时必须同时推迟供油提前角，才能获得较低的排放量组合。

提出了一种适合于车用涡轮增压柴油机实时仿真的压气机特性计算方法，应用方便，计算时间少。对一台6缸增压柴油机压气机特性的实例计算表明，此方法具有较好的计算精度。

Woody biomass was liquefied by water in an autoclave in the reaction temperature range of 280-420℃with sodium carbonate as the catalyst. The experimental results show that the yield of the main liquefaction product (heavy oil) was significantly influenced by the process conditions. The maximum yield of heavy oil was obtained at reaction temperature 380℃. The heavy oils obtained at different reaction temperature were analyzed by Fourier transform infrared spectroscopy (FTIR) and gas chromatography/mass spectrometry (GC/MS). The analytical results show the heavy oil is complex compound that contain hydrocarbon, aldehyde, ketone, hydroxybenzene and ester.