用CFD数值模拟方法研究了一种新型燃烧室设计——BUMP燃烧室对直喷柴油机喷雾燃烧过程的影响。模拟表明，bump环扰动缸内气流运动产生复杂的流谱，形成强烈的湍流，强化燃油与空气的湍流混合速度。此外，燃油喷雾撞壁后，bump环剥离壁面射流形成二次空间射流，减少了燃油在燃烧室壁面的沉积，湍流混合速率大大增加，燃烧过程得到明显改善。数值模拟解释了BUMP燃烧室在不增加燃油消耗的情况下获得低排放的实验现象。

采用气口顺序喷射、稀燃、全电控柴油/天然气双燃料发动机方案，对斯太尔WD615.64增压非中冷柴油机进行了改装。实验结果表明，改装后的发动机NOx、颗粒和NMHC排放均达到了欧II排放指标。CO和HC（含甲烷）可以通过后处理解决。

利用非线性规划理论，采用Lagrange-SUMT方法建立了电控发动机全工况范围内多变量、多目标的优化模型，并在全电控柴油引燃天然气发动机上进行了应用。实验结果证明，该方法可以减少优化参数的实验量，可以在较少的实验量基础上获得最优控制MAP。发动机的NOx，碳烟排放明显优于欧洲II排放标准，经济性与原柴油机相当。

作者提出了基于多脉冲喷射和BUMP燃烧室的MULINBUMP-HCCI复合燃烧技术。发动机实验和CFD数值模拟研究表明，多脉冲喷射参数，特别是多脉冲喷射定时可以控制预混合气的形成，从而控制燃烧放热率。具有分布式放热率的工作过程的热效率与直喷式柴油机相当。但同时改善了NOx和碳烟排放，在不采用废气再循环的条件下，NOx排放在较低负荷时只有11×10-6，高负荷时也不超过250×10-6。碳烟排放始终小于0.5BSU。

A sequential port injection, lean-burn, fully electronically-controlled compressed natural gas (CNG)/Diesel dual-fuel engine has been developed based on a turbo-charged and inter-cooled direct injection (D.I.) diesel engine. During the optimization of engine overall performance, the effects of pilot diesel and pre-mixed CNG/air mixture equivalence ratio on emissions (CO, HC, NOx, soot), knocking, misfire and fuel economy are studied. The rich and lean boundaries of the pre-mixed CNG/air mixture versus engine load are also provided, considering the acceptable values of NOx and THC emissions, respectively. It is interesting to find that there is a critical amount of pilot diesel for each load and speed point, which proved to be the optimum amount of pilot fuel. Any decrease in the amount of pilot diesel from this optimum amount results in an increase of NOx emissions, because the pre-mixed CNG/air mixture must be made richer, otherwise THC emissions would increase. However, the soot emissions remain almost unchanged at a very low level.