Influence of Coupling Action of Oxygenated Fuel and Gas Circuit Oxygen on Soot Generation in a Diesel Engine

Abstract

This paper focuses on a four-cylinder light-duty diesel engine and analyzes how the coupling action of oxygenated fuel and gas circuit oxygen impact soot generation based on tests where the in-cylinder ambient oxygen concentration is rich, medium, or poor. The test results show that ignition delay period and fuel oxygen content are major factors in soot value decreases, whereas in-cylinder combustion temperature hardly affects soot generation. Further analysis reveals that the weight of influence of ignition delay period and fuel oxygen content on soot generated by combustion of B (pure diesel) and B2 (2% n-butyl alcohol + 8% diesel by mass) fuels are different at various in-cylinder oxygen concentrations. For an oxygen content of .87% in the fuel, when there is rich oxygen inside the cylinders, the weight of influence on soot generation is 72.73–8.%; when there is a medium amount of oxygen, the weight of influence is 42.18–72.73%; in the case of scarce oxygen, the weight of influence is 41.43–42.18%. In terms of ignition delay period, when there is rich oxygen, the weight of influence is 2.–27.27%; in the case of a medium amount of oxygen, the weight of influence is 27.27–57.82%; and for only a little oxygen, the weight of influence is 57.82–58.57%.