Use of Hydrogen Peroxide to Improve the Performance and Reduce Emissions of a CI Engine Fuelled with Water Diesel Emulsions 2008-01-0653
Use of water diesel emulsions in diesel engines reduces simultaneously smoke and NOx emissions. However the ignition delay increases and there is a rise in the HC and CO levels as well. In this work hydrogen peroxide was added to water diesel emulsion and tested in a diesel engine. Initially the engine was run with water diesel emulsion (water to diesel ratio of 0.4:1). The water diesel emulsion with a H2O2/diesel ratio of 0.05 was used. The single cylinder diesel engine was tested at the rated speed of 1500 rpm. Brake thermal efficiency increased with hydrogen peroxide from 32.6% to 33.5% as compared to the plain emulsion at full load. These values are even better than neat diesel operation. CO and HC levels decreased significantly with the addition of H2O2. HC with the neat diesel engine at full load was 50 ppm. It rose to 75 ppm with water diesel emulsion and was controlled to 50 ppm when H2O2 was used. This is due to the strong oxidizing nature of H2O2. NO emission decreased slightly with hydrogen peroxide addition as compared to neat water diesel emulsion due to a reduction in ignition delay. Smoke emission also decreased due to better oxidation of the fuel. It is demonstrated through this study that even a small quantity of H2O2 can lead to a significant improvement in overall performance of the engine with water diesel emulsions. However, the long term effects have to be assessed.