A Study on the use of Water-Diesel Emulsions in a DI Diesel Engine

The objective of this work is to make a detailed investigation on the effect of using water diesel emulsions in a direct injection diesel engine. A single cylinder diesel engine was tested under variable load conditions at a constant speed of 1500 rpm at different water to diesel ratios of 0.3, 0.4, 0.5 & 0.6:1 by weight. Performance, combustion and emissions parameters were analysed and compared with pure diesel operation. Significant reductions in smoke density, NO concentraion and an improvement in brake thermal efficiency at high loads were achieved. Smoke level dropped from 3.7 BSU to 1.9 BSU and NO level dropped from 752 ppm to 463 ppm with a water to diesel ratio of 0.5:1, near full load. Water to diesel ratios of 0.4 to 0.5:1 were found to the optimal. Ignition delay, peak pressure, maximum rate of pressure rise, peak heat release rate and premixed burn fraction were higher as compared to diesel operation. Water diesel emulsions had an adverse effect on HC and CO emissions.