用快速压缩装置研究直喷式天然气发动机排放特性

使用快速压缩装置进行了直喷式天然气发动机排放特性的研究。测量了三种不同方式下的排放，并与均相混合气燃烧情况进行了对比。实验结果表明，在宽广的当量比范围内，天然气直喷方式的燃烧效率高于0.95。由于混合气的分层燃烧，天然气喷射方式在宽广的当量比范围内保持较低的HC排放量，同等功率下的低CO2排放量，低NOx排放量，其NOx排放在理论当量比处的降低更为明显。直喷天然气发动机既具备柴油机发动机效率高的特点，又具备预混燃烧发动机排放低的特点。

Emission Characteristics of Direct Injection Natural Gas Engine Using Rapid Compression Machine

Investigation of emission characteristics of a direct injection natural gas engine is carried out using a rapid compression machine.The emissions of three injection modes are measured and compared with that of the homogeneous combustion mode.The experimental results show that the combustion efficiency of the direct injection natural gas combustion is above 0.95 for all fuel supplying modes in the wide range of overall equivalence ratio.Fuel injection can operate within a wide range of equivalence ratio and has low unburned hydrocarbon emission (HC),low CO 2 emission for the same power output,low NO x emission due to the mixture stratification compared with homogeneous combustion engine,especially in the range near the stoichiometric equivalence ratio where engine power output is needed.Consequently,the direct injection natural gas engine has the advantages of high thermal efficiency like diesel engine and low emission of premixed mixture combustion.