Apr 9, 2008
Biofuels seem to be reaching the headlines on an almost daily basis, with some activist groups touting their benefits as part of a planet-saving strategy for fossil fuel alternatives. Other groups, of course, point out that you don’t get something for nothing and that ravaging ecosystems in order to plant crops for conversion does not provide as straightforward an answer as some people would have you believe. This is perhaps especially so for newer untested biofuel crops that may actually require more energy to produce and process into fuel than they save in unused fossil fuels.
Anyway, putting aside the politics aside and the balancing of energy equations, one question that car owners hoping to go green will want to know is – will biodiesel damage my engine? Writing in a forthcoming issue of the International Journal of Global Energy Issues (2008, 29, 303-313, in press), researchers in Turkey have begun a research program to try and answer that question. Their initial findings suggest that the answer is no.
Cem Sensogut, of Dumlupinar University, Kutahya, Turkey, and colleagues point out that biodiesel is not a twenty-first century invention. Diesel fuel derived from biomass as opposed to oil has been used as an alternative fuel since the early 1900s. The original diesel engine from 1895 was actually designed to be run on a variety of fuels rather than just petroleum-derived products. Moreover, Brazil pioneered the use of biofuels even before World War II with sugar-derived ethanol from sugar cane being trans-esterified to fuel in a major program that escalated during the 1970s oil crisis. Other countries have adopted biofuels quietly ever since for public transport and other initiatives.
Today, with the rising price of oil and an apparently urgent need to find other fuel sources there is renewed interest in making vehicle fuel from crops:
Biodiesel, in its purest form, consists of short chain alkyl esters derived from the transesterification of vegetable oils, animal fats, and algae. They can be used alone or blended with conventional diesel in unmodified diesel engines.
Sensogut and colleagues have analysed engine and vehicle components to discover that biodiesel does not cause long-term engine health problems. Of course, the manufacture of engines and vehicles is energy intensive and so if the environmental benefits of biofuels are offset by a shorter half-life for the global fleet of vehicles, then their use would be unviable in ameliorating pollution and climate change.
The researchers came to the following key conclusions for biodiesel made to ISO 14214:
- Pistons, intake valves, and engine exhaust are undamaged
- Engine power is unaffected by using winter biodiesel made from canola or soybean oils
- Engine power decreases by about 5% with summer biodiesel made from palm or sunflower oils
- Summer biodiesel leads to starting difficulties at temperatures below 15 Celsius
- Winter biodiesel, as the name suggests is best for autumn and winter use, but there starting difficulties at below 0 Celsius.
- No modifications are needed to a diesel engine except that fuel tank, fuel tank particle strainer and fuel filters have to be changed and cleaned regularly
Having obtained such positive results so far, the researchers are now investigating the effects of biodiesel on fuel-system components, injectors, pressure pumps. Should this ongoing work demonstrate conclusively that diesel engines are entirely safe with biodiesel fuels, then it will then only be a matter of resolving the political and environmental quandaries…simple…