Combined Effects of Injection Timing and Fuel Injection Pressure on Performance, Combustion and Emission Characteristics of a Direct Injection Diesel Engine Numerically Using CONVERGE CFD Tool

The infliction of rigorous emission norms across the world has made the automobile industry to focus and dwell upon researches to reduce the emissions from internal combustion engines, namely diesel engines. Variation in fuel injection timing has better influence on reduction of engine exhaust emissions. This papers deals with the variation of fuel injection timing along with fuel injection pressure numerically on a 4 stroke, single cylinder, and direct injection diesel engine running at full load condition using CONVERGE CFD tool. As the piston and bowl geometry considered in this work is symmetric, only 60 degree sector of the piston cylinder assembly is considered for numerical simulation over complete 360 degree model. To study the combustion and flow physics phenomenon taking place inside the engine cylinder and as well as to reduce the computational time, the numerical simulation is performed from 20 degree Crank Angle (CA) before TDC (bTDC) during compression stroke to 140 degree CA after TDC (aTDC) in power stroke as available in the literature. The standard injection timing of fuel from literature is 15.1 before TDC and this timing is advanced to 19 degree bTDC as well as retarded to 8 degree bTDC with variation in fuel injection pressure and its effects on performance, combustion and emission characteristics of direct injection diesel engine is studied. This numerical simulation has been carried out upon validation with 15.1 degree bTDC injection timing as available in the literature. The numerical results such as in-cylinder pressure, in-cylinder temperature, heat release rate with respect to crank angle (CA) has been predicted, analyzed and presented. Also the engine emissions like NO_X, soot, CO and HC are predicted for various injection timing with different fuel injection pressure.