Numerical simulation of NOx & soot emissions of single cylinder diesel engine with EGR modified to run on CRDI for high pressure split injections

Abstract

High pressure split injection with advanced fuel injection strategies is one of the prominent techniques for controlling the emissions NOx and Soot released from diesel engines however Exhaust gas recirculation (EGR) is one of the significant methods to control the engine emissions but research is limited for high pressure fuel injection technique. Various injection strategies like advanced and retarded injection angles are well known but proper published results for high pressure fuel injection is not available. At the same time these advanced injection strategies can control the injection pressure and fuel injection duration angle but nozzle orientation is fixed and cannot be changed frequently due to the manufacturing limits. Also, the choice of the fuel injection angles is trial based and hence accurate prediction of the engine performance is very much limited. To overcome this draw back numerical simulations using converge CFD software is performed for single cylinder diesel engine for EGR flow rates ranging from 0-15% on mass basis for 250bar injection pressure. The simulation results show that that 5% EGR flow rate for -11deg @250 bar fuel injection angle at injection pressure is effective in reducing the NOx and Soot emissions efficiently when the engine run on ULSD diesel fuel with cooled EGR.