High-Pressure Viscosity of Soybean, Canola and Coconut Biodiesel

Viscosity is a significant physical property in the design of injection systems for diesel engines. Injectors often reach pressures greater than 1000 atmospheres. Determining the differences in viscosity of diesel and biodiesel fuels at elevated pressures may aid in the development of more efficient and environmentally friendly engines. The viscosity of #2 diesel and biodiesel from feedstocks of soybean oil, canola oil, used canola oil, high-stability soybean oil, and coconut oil was found for temperatures of 10, 25,40 and 100 ̊C at pressures, which ranged from 0 to 19,000 psig. Using non-linear regression, the data was fit successfully to a Tait-Litovitz equation. The Tait-Litovitz equation allows for the prediction of a particular fuel's viscosity as a function of temperature and pressure. The correlation was able to predict the viscosity to 1.5% absolute average relative deviation for all isotherms.