A Review of the Effect of Compressed Natural Gas (CNG) on Combustion and Emission Performance of Internal Combustion Engines

In order to reduce the environmental pollution caused by conventional internal combustion engines, the application of natural gas in internal combustion engines and the combustion and emission performance of natural gas internal combustion engines have been widely studied by scholars. Because the physical and chemical properties of natural gas are different from those of conventional gasoline or diesel, the operating performance of natural gas internal combustion engines in practical applications is also different from that of conventional internal combustion engines. This paper presents the physicochemical properties of compressed natural gas, the two combustion modes (premixed combustion and non-homogeneous diffusion combustion) in internal combustion engines and the effect of compressed natural gas on the performance of internal combustion engines. Compared with gasoline engines, natural gas internal combustion engines have relatively lower power and higher effective power loss; lower effective fuel consumption rate in terms of economy; and lower CO and NOx emissions than gasoline engines in terms of emissions.