An Experimental Way of Assessing the Application Potential of Emulsified Palm Biodiesel Toward Alternative to Diesel

Amid various methods available to reduce pollutant emissions and to improve performance and combustion characteristics of a diesel engine, emulsified fuel seems to be promising. However, because of its different properties from diesel, a biodiesel emulsion is incompetent to provide standard diesel performance. Once combusted in a diesel engine; the proper adjustment of engine operating parameters with the presence of "microexplosion" may amend the performance of a biodiesel emulsion run engine. In order to realize this fact, a comprehensive study has been carried out in a variable compression ratio diesel engine running with two-phase water in a palm biodiesel emulsion. The engine operating parameters studied and optimized are compression ratio (CR), injection timing (IT), and load. The water emulsions of palm oil methyl ester (WIP) with various specifications have been prepared by commercially available surfactants with appropriate HLB values. Water quantity (5% and 10%), surfactant quantity (1%, 2%, and 3%), and HLB values (4.3, 5, and 6) are the parameters optimized to attain the stable WIP by means of mean droplet diameter measurement and stability study. The optimized WIP of 5% water, 3% surfactant of 6 HLB is then tested in a diesel engine at varying CR (17, 17.5, and 18) and IT (20, 23, and 28 deg BTDC). For each of the combinations of CR and IT, the load has been varied from idling conditions to full load (12 kg) with an increment of 20% (2.4 kg) and 110% (13.2 kg) of full load. The results are analyzed in the form of performance, combustion, and emission parameters with respect to the baseline diesel run (CR = 17.5 and IT = 23 deg BTDC).