Optimum injection timings for bioethanol-diesel blends and its effect on tail pipe emission in common rail diesel engine

Abstract

computational study of a CRDI engine is carried out to examine the performance and tailpipe emissions the with bioethanol blended diesel fuel for various injection timing. The simulation ponders various bioethanol diesel blends (0-30 %), and for several injection timings from 21°- 33° BTDC in the interval of 3°CA, at ∼90MPa injection pressure. The k-ς-f model is used to simulate turbulence inside the cylinder. Combustion study is analyses is carried by using three zone extended coherent flame model. Equivalence ratio for all the cases of blends is kept constant and equal to the case of neat diesel (E0). Optimum injection timing (IT) is obtained for maximum indicated thermal efficiency (ITE) for bioethanol diesel blends operation. The maximum indicated thermal efficiency for E0, E10, E20 and E30 is found at 27°, 27°, 30° and 33° IT respectively. Significant increase in ITE of ∼5% is observed in the case of E30 compared to diesel (E0). Effect of IT on tail pipe emissions such as NO, soot and CO formation is also obtained. The results indicate that ignition delay increases and mean soot formation decreases with advancing the IT's. For all advanced IT higher in-cylinder peak pressure and temperature are observed. Obtained results are validated with available literature data and found a good agreement. © 2021 Author(s).