Liquefied alternative fuels offer great potential benefits in reducing exhaust emissions and improving fuel economy of automotive engines. In order to achieve the best performance of the engine running with such fuels, it is critical to have an appropriate fuel system. In the present work, a new electronically controlled common-rail injection system has been specially designed and tested for the direct injection of liquefied alternative fuels, since a conventional pump-line-injector injection system in the conventional diesel engine was not suitable for the purpose. Experimental work has been carried out to examine and improve matching of the fuel injection system on a new fuel injection pump test bench. The preliminary engine bench test has demonstrated that this arrangement meets the requirement for the operating characteristics of a fuel injection system in a direct injection diesel engine operating with dimethyl ether (DME).

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。

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。

This paper reports the development of a new prechamber combustion system of the 2190T natural gas engine. The experimental results show that the new combustion system is reliable and practical, and that the performance of the engine is greatly improved due to stable ignition and fast flame propagation in prechamber and high burning rate and short burning period in main chamber.

This paper presents a dual fuel system for diesel-natural gas operation for a truck diesel engine, and describes results of testing and analysis of the operating characteristics of the engine. The research results show that rates of fuel consumption and fuel efficiencies are increased with this engine design, and heat consumption decreased with increasing load on the engine. The heat consumption rates at medium-high loads are lower than at light loads. At full loads, the dual fuel engine exhibits heat release in which start combustion is reduced and the following combustion is rapid. The engine is tested with an electronically controlled method to meet the requirement of engine output torque.