Optimization research of SOOT and NOX on a diesel engine fueled with F-T based on multi-objective analysis
In order to fully play the excellent physicochemical characteristics of F-T coal-to-oil and improve the trade-off relationship between SOOT and NOX of diesel engineeffectively,a four-cylinder diesel engine was taken as the research object,and SOOT and NOX was taken as the optimization target.The test bench was used to obtain performance data with the variation of injection parameters.According to these test samples,a numerical simulation model for SOOT and NOX prediction under different injection parameters was established by SVM,which was used as fitness function of NSGA-Ⅱ(Non-dominated Sorting Genetic Algorithms-Ⅱ),and then the Pareto solutions of SOOT and NOX were found in the sample spaces.On this basis,SOOT and NOX targets were endowed with weights by means of Topsis analysis method,and then the principles of Pareto decisions were described.As a matter of fact,Pareto solutions decided by Topsis method showed a marked drop compared to the original points,in which SOOT declined 3.7%-7.1% and NOX declined 1.2%-2.6% .At last,the validity of the results was demonstrated by the experiments,which showed that the maximum relative error of SOOT simulations was 8%,while it was 5% for NOX simulations,and R2 under various operating conditions were more than 0.95.In this paper,analysis shows that the methods make a significant improvement in the trade-off relationship between SOOT and NOX emissions,which can improve emission performance of direct injection diesel engine.
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