Experimental And Simulating Studies Of Diesel Engine Fueled With Bio-diesel With F-T Diesel Blends

With the shortage of energy and increasingly stringent of emission regulations in our country, the primary task for achieving the sustainable development of the diesel vehicles is looking for alternative fuels and reducing NOx and soot emissions. It is showed that diesel engine fueled with biodiesel could dramatically reduce soot emission but correspondingly increase in fuel consumption rate and NOx emission because of its high viscosity and containing oxygen. Bio-diesel blended with F-T diesel can not only improve the problem with high viscosity but it also reduces NOx emission and fuel consumption rate. Diesel engine fueled with F-T diesel and biodiesel blended fuels has better practicability.To grasp the combustion characteristics of two types of fuels and determine the optimum mixing ratio, the power, economy and emission of diesel engine fueled with biodiesel and F-T diesel blends were first analyzed and simulated. The result shows that B20F, B50F, B80F (B20F expresses that volume fraction of biodiesel accounts for20%+FT diesel accounts for80%, etc.) blends could effectively reduce NOx emission and fuel consumption rate. In particular, B50F mixed fuel can significantly improve the economy of diesel engine and NOx emission in the premise of ensuring power performance. Meanwhile, combustion parameters was more optimized by the simulation study, which makes economy and emissions further improved.To further improve the economy and emissions of diesel engine, researching combustion process in cylinder of diesel engine and optimizing combustion system parameters has an important significance to improve the combustion status, increase the combustion efficiency and reduce the generation of emissions. The effect of different combustion system parameters on combustion process of diesel engine fueled with B50F mixed fuel was simulated under the load characteristics of maximum torque speed by AVL-FIRE which has low cost, short cycle and can easily change parameters. Basis on this, the significant influencet of combustion system parameters on the performance of diesel engine was judged by orthogonal design method. All the study parameters which are based on effective power, fuel consumption rate, NOx emission and soot emission as evaluation index were optimized. The results show that impact of swirl ratio and injection advance angle on NOx emission and soot emission, fuel consumption rate, effective power is the greatest in all factors. The mpact of injection duration on NOx emission is the largest. The impact of injection duration on soot emission, fuel consumption rate and effective power is not significant. The impact of combustion chamber parameters on NOx emission is significant. The impact of combustion chamber parameters on soot emission, fuel consumption rate and effective power is highly significant. Finally,9optimization schemes are put forward according to the variance analysis and the optimization results are validated through the simulation. The optimization schemes A1B3C3D1of diesel engine fueled with B50F mixed fuel under the moderate load of maximum torque speed can simultaneously reduce NOx and soot emissions and improve power performance and economical performance.