Engine fuel characterisation through ultraviolet absorption spectra

In the article, light absorption properties of the fuel oil are considered with a view to create basis for establish optical indicator of the type and quality of this kind of crude oil derivative, in this case the Diesel fuel. The organic solvent – n-hexane – was chosen as a solvent to prepare samples of dilutions of Diesel fuel in several oil concentration. Spectrophotometer Aqualog Horiba were applied to record the absorbance spectra in the ultraviolet and visual range of the light (from 240 to 600 nm) for each previously prepared samples. Obtained results allow concluding that the changes of absorbance occur primarily in the wavelength range from 240 nm to 355 nm. Moreover, the absorbance spectra are characterized by the characteristic sharp peak located at 270 nm for excitation wavelength. Spectra of absorbance were converted to spectra of absorption coefficient based on Lambert-Beer law. Due to the independence the absorption coefficient from the fuel concentration, this parameter could be used as a potential indicator to access composition and quality Diesel fuel used in the diesel engine system. Therefore, preliminary tests allow concluding that absorption coefficient for selected wavelength located at 270 nm could be a sensitive indicator for quick access to fuel quality.