Study of nitrogen oxides content in the cylinder of turbocharged tractor diesel engine operating on natural gas

Abstract

The article is devoted to the application of compressed natural gas as an alternative fuel and the reducing of nitrogen oxides content in exhaust gases of turbocharged diesel engine. Special attention is paid to the problems of formation and decomposition of nitrogen oxides in the cylinder of diesel engine operating on natural gas and its effect on the combustion process. In order to determine and optimize the main parameters of operation of turbocharged diesel engine on natural gas, the block tests for both diesel and gas-diesel processes were conducted; they showed that the diesel was running steadily on compressed natural gas under nominal mode at a ratio of 80% of gas and 20% of ignition portion of diesel fuel. Further, the research of working process was carried out exactly in that ratio. The article presents the results of experimental studies of the effect of compressed natural gas on the indices of exhaust toxicity and smoke opacity. The values of volume content and mass concentration of nitrogen oxides in the cylinder of diesel engine depending on the crank angle change are analyzed and determined. The indices of combustion process of turbocharged gas diesel engine under different load and speed operating modes are given. Analysing the obtained results, one can conclude that the application of compressed natural gas as an alternative fuel in turbocharged diesel engine is efficient and allows to reduce exhaust toxicity. Thus, with optimum advance angle of fuel injection of 11 degrees, when switching to gas-diesel process, the nitrogen oxides content in exhaust gases reduces by 15.5%, the soot - by19 times, and the carbon oxide - by 18%.