Received: February 1st, 2021 ; Accepted: May 2nd, 2021 ; Published: May 4th, 2021 ; Correspondence: [email protected] viscosity and density are important fuel properties because they influence
fuel atomisation during injection into the engine cylinder. The viscosity and density of neat
vegetable oils usually are too high to allow optimal use of these oils in compression ignition
engines. Blending vegetable oils with alcohols can improve these properties, but it is not known
whether the blend properties remain stable during storage. This study measured kinematic
viscosity (at 40 °C), density (at 15 °C) and surface tension of rapeseed oil-alcohol blends that had
been stored in closed borosilicate glass bottles at room temperature in the dark for 49 weeks. The
values were compared with those of the fresh blends. Further measurements of oxidation stability
for the rapeseed oil and the blends were taken after 72 weeks of storage. The blends consisted of
rapeseed oil with ethanol at 5 vol–%, and rapeseed oil with 1–butanol at 5 vol–%, 10 vol–%, 20
vol–% and 30 vol–%. All in all, the observed changes during storage were small. Density values
deviated by less than 1%, surface tension by no more than 3% and kinematic viscosity differed
from the fresh blends’ values by 1% to 8%. Surface tension had increased in some blends and
decreased in others. Kinematic viscosity rose in all blends, with the smallest increase measured
for the rapeseed oil–butanol 30 vol–% blend. This blend also showed the best oxidation stability,
which was close to six hours
