Experimental Investigation of Biodiesel Blends with High-Speed Diesels—A Comprehensive Study

Biodiesel is a clean-burning, alternative diesel replacement fuel that may be used in existing diesel engines in either pure or blended form without or with modest modifications. In some countries, biodiesel is recommended as a potential alternative to diesel fuel since it is a renewable energy source that is environmentally benign. The main problems with the widespread commercialization of biodiesel are its high viscosity and its limited feedstock, due to which complete replacement of diesel fuel is not possible and the use of blends of biodiesel and petrodiesel are being used increasingly worldwide. The paper presents a behavioral study of the petro-based diesel, and their blend (B20, B40, B60, B80) with Pongamia and Jatropha biodiesel. The results reveal a considerable viscosity lowering due to the dilution effect of increasing diesel concentration in both the cases. In addition, improvements in oxidation stability in both cases have also been observed. The research shows that as the biodiesel concentration increases, the stability of blends decreases. In blending Jatropha curcus methyl ester with EURO-III and EURO-IV HSD, the ester’s viscosity decreased as the diesel level in the blends increased, and blends comprised up to 80 percent biodiesel remained below the viscosity limit. Pongamia pinnata blends with both fuels above 60% diesel; however, exceeds the stipulated viscosity limit of 4.50 cSt at 40 °C.