Experimental Study On The Effect Of Fuel Injection Paramenters On Emission Of Common Rail Diesel Fueled With F-T Diesel

The continuous progress of science and technology promotes the vigorous development of China's coal chemical industry.Many coal enterprises are engaged in the production of liquid clean fuel from coal.This technology can liquefy a large number of coal into liquid fuel(F-T diesel is one of them),and this fuel can be directly used in diesel engines.The cetane number and c(H)/c(C)of F-T diesel fuel are all higher than 0#diesel fuel,which is conducive to reducing the emission of NO_X and soot.In order to further reduce the emission of F-T diesel fuel to meet increasingly stringent emission regulations,this paper applies F-T diesel fuel to a common rail diesel engine,and adjusts the injection parameters(injection pressure,main injection timing,pre-injection duration,pre-injection pulse width)of common rail diesel engine.The relevant bench tests were carried out to try to reduce emissions by changing the injection parameters of diesel engines.Injection pressure rises from 97MPa to 142MPa,the combustion characteristic parameters in cylinder are improved in varying degrees,which makes the mixing degree of mixture in cylinder more fully,the combustion situation improved,the power performance of F-T diesel engine improved,the economic performance increased first and then decreased,the emissions of soot,carbon monoxide and hydrocarbons decreased,and the emissions of nitrogen oxides increased by about 40%,which is also related to fuel injection.Increased pressure and better fuel atomization combustion are closely related,which can obtain higher energy and reduce major pollutant emissions.The main injection timing rises from 1.8°CA BTDC to10.8°CA BTDC,the in-cylinder pressure,in-cylinder pressure rise rate and in-cylinder temperature are increased,the instantaneous heat release rate decreases slightly,and the peak phase of each combustion parameter is advanced,which is related to the increase of the main injection timing,which prolongs the ignition delay period in the combustion process;the power and economy of F-T diesel engine are improved,soot,hydrocarbons,monoxide.Carbon emissions decreased by39.63%,81.43%and 34.7%respectively.Nitrogen oxide emissions increased by more than 90%.Early fuel injection made the mixture more uniform and obtained higher in-cylinder temperature,thus making combustion more fully.Most of the pollution emissions decreased,while NO_X emissions increased due to the increase of in-cylinder temperature.Pre-injection timing rises from 15.7°CA BTDC to 30°CA BTDC,the peak values of in-cylinder pressure,in-cylinder pressure rise rate and in-cylinder temperature decrease,the peak values of instantaneous heat release rate in pre-injection stage decrease,and the peak values of instantaneous heat release rate in main injection stage increase.The power and economy of F-T diesel engine decrease in varying degrees,and the emissions of soot,nitrogen oxides decrease by 8%and 30.08%,hydrocarbons,carbon monoxide and carbon monoxide decrease.The emission increases slightly and the main pre-injection interval increases,which results in the combustion phase being far away from the top dead point,brings resistance to the compression stroke,reduces the power economy,and decreases the NO_X emission is related to the temperature drop in the cylinder.Increasing the main pre-injection interval also makes the formation of combustible mixture more uniform and thinner,effectively reduces soot emissions,but increases CO and HC emissions.Pre-injection duration rises from 283?s to 362?s,the in-cylinder pressure and pressure rise rate increase gradually,the instantaneous heat release rate and in-cylinder temperature of pre-injection combustion increase gradually,the instantaneous heat release rate and in-cylinder temperature of main injection combustion decrease gradually,and the increase of pre-injection quantity can bring more heat;the power and economy of F-T diesel engine decrease slightly,and the emissions of soot,nitrogen oxides and hydrocarbons.Increased by 8%,23.54%and 93.9%respectively,and CO emissions decreased by 12.32%.The two-factor variance analysis method in statistical theory was used to study the influence of the two factors on the main emissions,and the degree of the impact was qualitatively analyzed.The results showed that the injection pressure and the main injection advance angle had a certain impact on the emission of NO_X and soot.Changing the main injection advance angle had a greater impact on the emission of NO_X,and changing the injection pressure had a greater impact on soot emission.Finally,four optimization points of fuel injection parameters are selected and tested on diesel engine.It is found that NOX and soot have been greatly improved after comprehensive optimization.Therefore,it can be concluded that optimizing fuel injection parameters has a certain effect on improving the emission of major pollutants.Therefore,it is one of the effective measures to solve the problem of diesel engine emissions to adjust the fuel injection parameters timely according to the working conditions of the engine fueled with F-T diesel in order to reduce its pollution emissions,and to properly adjust the combustion parameters of the engine.