Comparative Study On The Combustion And Emission Characteristics Of Isopropanol Diesel And N-pentanol Diesel Blend Fuels

As an important source of internal combustion engine,diesel engine is widely used in industrial and agricultural fields,such as power generation,irrigation,automobile and ship transportation,due to its high thermal efficiency and energy efficiency.However,the higher PM and NOx emissions of diesel engines not only cause a series of very serious air pollution problems,but also limit its further promotion and application,but also endanger human health.Alcohol fuels have low cetane number,low kinematic viscosity,self-oxygenation,and the addition of a certain proportion of alcohol to diesel fuel can effectively improve the physical and chemical properties of diesel low-temperature fluidity,oxygen content,etc.,and reduce PM emissions from diesel engines,but at the same time lead to NOx raises the problem.Therefore,the combustion of the gasoline/diesel fuel in the low temperature combustion mode(LTC)of the engine can effectively solve the problem of high NOx emissions when the diesel engine is used with the fuel.In addition,diesel engines do not require modifications to the diesel fueling system and other structures when burning gasoline/diesel blends.This test uses 0# pure diesel as the base oil(labeled as D100),isopropanol and n-pentanol as the blending fuel,and added to 0# diesel oil according to the volume fraction of20% to prepare isopropanol/diesel and n-pentanol/ diesel fuel blends,labeled D80P20 and D80W20,respectively.The test was carried out on a supercharged intercooled high pressure common rail four-cylinder diesel engine and analyzed for combustion and emissions characteristics of diesel and mixed fuel.Research indicates:1.Compared to diesel,blended fuels have lower calorific value,cetane number,density,viscosity,cold filter point and freezing point.The quality of the mixed fuel evaporation atomization is significantly improved.2.Under all test conditions,the injection strategy of the engine when burning three kinds of fuels is pre-injection plus main injection;under the same working condition and EGR rate,when the engine is fueled by D100,D80P20 and D80W20,the two kinds of mixing Thein-cylinder pressure,in-cylinder combustion temperature,and peak heat release rate of the fuel are both slightly higher than D100.As the EGR rate increases,the in-cylinder pressure,the in-cylinder combustion temperature,and the peak heat release rate decrease.3.Under the same working conditions and EGR rate,when the engine is fueled by D100,D80P20 and D80W20,the NOx emissions of the two mixed fuels are higher,and the total concentration and total volume concentration of soot and ultrafine particles are less.As the EGR rate increases,NOx emissions decrease and soot and particulate matter emissions increase.