Comparison of performance and emission characteristics of diesel and diesel-water blend under varying injection timings

The present work is focused on comparison of diesel and diesel-water blend on emissions and performance parameters of the diesel engine. The emission parameters such as NO, CO and soot are investigated numerically by using commercially available CFD software AVL FIRE. In addition to that, performance parameters in terms of thermal efficiency, indicated power, torque and brake specific fuel consumption is also analyzed numerically. For better understanding of the software, two validations are provided in the present study. In first validation, the commercial code is validated by experimental data available in the literature; and it is found to be satisfactory in terms of pressure and temperature. Whereas, second validation is taken out with model-TV1 of Kirloskar single cylinder diesel engine and results of pressure and heat release rate are acceptable. Numerical simulation is conducted on a four-cylinder, 1.9L GM diesel engine with piston having a rectangular cavity. The blend is prepared by using 95% diesel and 5% water and compared with diesel fuel. As a part of the above study, injection timing is varied as 6°, 10° and 14° BTDC for diesel as well as diesel-water blend. The result shows that, diesel-water blend reduces emission without affecting the engine performance parameters, when engine fueled with diesel alone. Nevertheless, at an injection angle of 6° BTDC, diesel-water blend with 5% by mass is seems to be an effective substitute in diesel engines in terms of engine emissions and operation parameters. Keywords: Diesel engine, combustion modeling, diesel-water blends, NO, CO and soot emission, efficiency and power