Last updated June 28, 2018 at 9:51 am
Research points to fresher-smelling fumes.
Perfumed diesel is, perhaps, more an aesthetic improvement than an environmental or atmospheric one, but if it makes life more bearable for people who have to endure polluted air then that’s no bad thing.
Research by a team led by Queensland University of Technology scientist Ashrafur Rahman and published in the journal Energies demonstrates that waste oils from eucalyptus, tea tree and orange processing can be added to diesel fuel, changing the smell of the product without introducing significant performance loss.
Rahman’s idea is to utilise a by-product of plant processing. Significant quantities of citrus fruits, eucalyptus and species such as tea tree are treated for the extraction of oils. These are used in the manufacture of a range of generally high-end consumer products, including essential oils, disinfectants and beauty applications.
However, only the best quality extracted oils are used, leaving a considerable stockpile of lower-grade material currently stockpiled.
Essential oil blends
Rahman mixed each of the leftover oils with diesel, such that they made up 10% of liquid volume, then placed the result in a six-cylinder, 5.9 litre diesel engine and tested the system for efficiency and emissions. For comparison, he also repeated the tests using 100% diesel, and a mix of 90% diesel and 10% waste cooking oils.
The results were mixed.
“Our tests found essential oil blends produced almost the same power as neat diesel with a slight increase in fuel consumption,” the researcher says.
“Diesel particulate emissions, which are dangerous to human health, were lower than pure diesel, but nitrogen oxide emissions, a precursor to photochemical smog, were slightly higher.”
Further research needs to be done, but Rahman sees his process as a potential boon for many people, starting with those living in regional areas.
“Orange, eucalyptus and tea tree are either native or grown extensively in Australia for essential oil production,” he notes.
“We see the main use for an essential oil-diesel blend would be in the agricultural sector, especially in the vehicles used by the producers of these oils.
“With further improvement of some key properties, essential oils could be used in all diesel vehicles.”