Cotton Seed Oil Blends as an Alternative Fuel for Variable Compression Ratio CI Engine: A Review

摘要

This article is a literature review of use of cotton seed vegetable oil (biodiesel) as a fuel for variable compression ratio CI engines. This study is based on the reports of about 40 scientists including (some manufacturers and agencies) who published their results between 1996 and 2010. The scientists and researchers conducted the test, using different types of raw and refined vegetable oils. These experiments with raw vegetable oil as fuel did not show the satisfactory results. A vast majority of scientists mixed the transesterified vegetable oil/biodiesel oil with diesel with different ratios. According to some scientists, when vegetable oil tested in long run, blends of the oil above 20% (B20) caused maintenance problems and even sometimes damaged the engine. Some authors reported success in using vegetable oils as alternative to diesel fuel in blends of more than 20% even in long-term studies. The main conclusion derived by the researchers is that coking is a potentially serious problem with the use of unmodified vegetable biodiesel. However, the refined, chemically processed (transesterified) vegetable oil mixed with diesel can be used to run compression ignition engine for longer duration. It was reported that there was a slight decrease in brake power and a slight increase in fuel consumption. However, the lubricant properties of the vegetable oil are better than diesel, which can help to increase the engine life. Moreover, the vegetable oil fuel is environment friendly, produces much less NO_x and HC and absolutely no So_x and no increase in CO_2 at global level.