Research and development of heavy-duty NG engine and its key technologies of combustion

Abstract

In this paper, A heavy-duty NG engine and its electronic controlled system were developed. combustion stability, in-cylinder flow, burning rate and hazardous emissions were further investigated to develop optimized combustion control technologies for efficient and clean combustion on this engine. The electronic controlled system and NG supply system were designed in the condition of maintaining the universal parts of based diesel engine as many as possible. The combustion and emissions of NG engine were investigated by means of experiment and numerical simulation with the commercial 3D-CFD-tool STAR-CD. The in-cylinder flow and burning rate of NG engine were studied. Special-shaped combustion chamber was used to change the flow state. The results show that the engine thermal efficiency increases by 2 % compared with the original engine while using the cross-type rapid combustion chamber under 1450r/min,100 % load operating condition. Effect of three kinds of dilution methods on combustion and emissions performance from lean burn NG engine was investigated. These dilution methods include air dilution, stoichiometric combustion with EGR, and double dilution (extra air and EGR). The results show that double dilution method is superior to other methods no matter considering from fuel economy or NOx emissions. © 2013 Springer-Verlag.