高压缩比主动射流点火氨氢发动机燃烧特性研究

The effects of the active/passive jet ignition mode, engine compression ratio, pre-chamber injection pressure and hydrogen mixing ratio on the combustion characteristics of the jet ignition ammonia-hydrogen engine were investigated by numerical simulation. The results show that increasing the engine compression ratio has little effect on the combustion rate of the mixture in the cylinder under high ammonia mixing ratio and passive jet ignition mode. Compared with the passive jet ignition mode, the active jet ignition can obviously improve the ignition ability and mixture combustion speed of the engine under the condition of high ammonia content. Increasing the active injection pressure can accelerate the combustion rate of the mixture in the cylinder and shorten the combustion duration, but too high active injection pressure will lead to local concentration of hydrogen in the cylinder and reduce thecombustion efficiency of hydrogen. Increasing the hydrogen blending rate of the inlet mixture can improve the combustion efficiency of ammonia and hydrogen, increase the flame intensity of the flame jet and accelerate the combustion in the cylinder. Under the same working condition, the indicated thermal efficiency can be increased by 3.1 percentage by the lower compression ratio of the high compression ratio ammonia-hydrogen active jet ignition engine.