Oxygen N-butyl Alcohol Fuel On Diesel Engine Combustion Path Effect Of Simulation Research

Facing with the rapid development of internal combustion engine industry,people’s energy and environment problem increasingly prominent,in order to achieve the internal combustion engine clean combustion,now looking for new alternative fuel is imminent.N-butyl alcohol,with its high low calorific value,and diesel as well as good intermiscibility gradually become the representative of the clean fuel,a lot of the experimental results showed that in the diesel blending proportion of n-butyl alcohol,can effectively reduce the engine emissions,so as to improve the combustion and emission characteristics of diesel engine.Therefore,research on the application of n-butyl alcohol on the diesel engine to realize the internal combustion engine clean combustion is very necessary.Through numerical simulation method,this paper studied n-butyl alcohol oxygenated fuel on diesel engine combustion and emissions.First of all,through 3 d numerical simulation software AVL engine-the FIRE to modeling of engine combustion chamber,and the refined n-heptane-n-butyl alcohol-mechanism of polycyclic aromatic hydrocarbons as n-butyl alcohol-chemical reaction kinetics mechanism of diesel fuel mix combustion.Through the test value of the average pressure in cylinder and the simulation value,shows they are consistent,therefore this model has high accuracy,can be used for further research.Secondly,analyzed the mixing proportion in diesel n-butyl alcohol,on diesel engine combustion,the influence of nitrogen oxide and carbon smoke emissions.When mixed with certain proportion of n-butyl alcohol in diesel oil,n-butyl alcohol will with n-heptane for OH radicals dehydrogenation reaction,and leading to n-heptane oxidation reaction to slow down.NO formation can be divided into three kinds,namely high temperature type NO,fast,NO and NO fuel type,n-butyl alcohol added to can make the mixed fuel in diesel oil cetane number is reduced,ignition delay period longer,slower burning rate,which results in the decrease of temperature in cylinder,inhibit the reaction of oxygen and nitrogen in the air in the fuel,reduce the NO generation.Carbon smoke generation process consists of a hydrocarbon fuel,high-temperature pyrolysis,nucleation stage,growth,condensing several stages,such as surface,and through the analysis of acetylene(HACA mechanism)dehydrogenation mechanism gradually grew up,and the addition of n-butyl alcohol can reduce the concentration of acetylene,lead to the formation of carbon smoke.At the same time,n-butyl alcohol in the combustion process produces a large number of OH radicals that make the OH radical increase in fuel blends,accelerate the smoke generated in the process of some small molecules(such as C2H2)oxidation.And n-butyl alcohol added to make the O atom increase in fuel mix,promote the combination of O and C atoms in molecules,the formation of more C-O key,reduce the chance of a combination of C and C atoms,which inhibits the smoke generated reaction,achieve the goal of reducing carbon smoke emission.AVL-FIRE software was used to establish model,studies the different proportion of n-butyl alcohol,fuel injection advance Angle of n-butyl alcohol-such as combustion and emission characteristics of diesel fuel mix.The result shows:the proportion of n-butyl alcohol and fuel injection advance Angle is mainly through affecting the ignition delay period,mixed fuel in cylinder pressure impact on combustion and emission characteristics of a hybrid.Is butanol as diesel blending ratio increases,the maximum explosion pressure in cylinder and the average temperature in cylinder is reduced,indicating fuel consumption rate was increased,NO smoke and carbon precursors benzene(A1),naphthalene(A2),Philippines(A3)and pyrene(A4)the generation time lag and the mass fraction of reduced trends;With the decrease of the fuel injection advance Angle and average in cylinder pressure curve is added,the maximum explosion pressure in cylinder at this time also gradually reduced,the production of NO time lag,the generation is gradually reduced,and the generation of NO areas are mainly distributed in the pits of the cylinder wall surface and the combustion chamber,the formation of carbon smoke precursors A4 moment also lagging behind,A4 mass fraction curve peak slightly elevated.