On the origins of lubricity and surface cleanliness in ethanol-diesel fuel blends
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AuthorsHong, Frank T.
KAUST DepartmentChemical Engineering Program
Clean Combustion Research Center
Combustion and Pyrolysis Chemistry (CPC) Group
Mechanical Engineering Program
Physical Science and Engineering (PSE) Division
Online Publication Date2021-06-04
Print Publication Date2021-10
Embargo End Date2023-06-04
Permanent link to this recordhttp://hdl.handle.net/10754/669396
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AbstractEthanol is the most used bio-derived fuel additive. However, adding ethanol in diesel fuel may negatively impact lubricity or surface cleanliness, which is critical for high-pressure fuel injection systems employed in compression ignition engines. This work investigates surfaces lubricated by ethanol–diesel blends. Adding 5 wt% ethanol in diesel showed negligible changes in fuel lubricity, while blending 10, 20, and 40 wt% ethanol increased wear rates by 46, 81, and 239% respectively. These increases in wear rates (with increases in ethanol by wt%) correlate with the evolution of electrical contact resistance (ECR) values over time. As more ethanol was added, the ECR values signaled thinner fuel films, more metal-to-metal contacts, and a delayed onset of frictional product growth. Raman spectra showed that forming frictional species produced by tribochemical reactions enhanced fuel lubricity. The absence of some frictional species in ethanol lubricated surfaces points to simultaneously improved surface cleanliness and reduced lubricity.
CitationHong, F. T., Singh, E., & Sarathy, S. M. (2021). On the origins of lubricity and surface cleanliness in ethanol-diesel fuel blends. Fuel, 302, 121135. doi:10.1016/j.fuel.2021.121135
SponsorsThe authors would like to acknowledge the fund allocated to this research by Saudi Aramco and King Abdullah University of Science and Technology (KAUST).