改善热面点火天然气发动机起动和运转性能的研究

Investigation on Improving Starting up and Operating Characteristics of Glow Plug Natural Gas Engine

针对热面点火天然气机起动困难以及低负荷循环波动大、高负荷燃烧敲缸、NOx排放数值较高的问题,通过台架试验,分别研究了3种燃料添加剂、进气加热温度、隔热措施及热EGR对发动机起动和运转性能的影响.结果表明,采用3种添加剂、提高进气温度和燃烧室隔热,有利于天然气着火起动和稳定燃烧.采用热EGR有助于天然气发动机扩展功率范围并有利于降低NOx排放.

To solve the difficulty in starting up, unstable combustion in low load condition, and knocking phenomenon and high level NOx emission in high load condition, which exist in the compression natural gas （CNG） engine with glow plug ignition, the effect of three kinds of fuel additives, inlet air heating temperature and heat exhaust gas recycle （EGR） on the starting up and operating characteristics of the engine are investigated through bench test. The experimental results show that adding additives, increasing charge-air temperature properly and implementing low heat release on combustion chamber components are advantageous to CNG ignition and stable combustion. Applying heat EGR is helpful for extending the output of the engine and decreasing the NOx emission level.