Combustion evaluation of Diesel - Soyabean methyl ester blends using variable piston geometry in direct injection compression ignition engine

The present paper is focussed on analysing experimentally the combustion and heat release characteristics of Soyabean biodiesel in compression ignition engine. Biodiesel is formed by transesterification of Soyabean crude oil using sodium hydroxide and methanol which resulted in 95% of Soyabean biodiesel. The piston geometry of the engine was varied by erosion and electrochemical deposition of metals to form Deep Torodial and Shallow Torodial combustion chamber. The results showed that SOME biodiesel exhibits better combustion characteristics with Shallow Torodial piston geometry than Deep Torodial piston geometry. The combustion peak temperature was increased by 4% to 6% in Shallow Torodial piston where as Deep Torodial piston showed 3% to 5% negative improvement in cylinder pressure. The rate of heat release also showed positive improvements with Shallow Torodial piston geometry. Keywords: Soyabean biodiesel, Combustion, Rate of heat release, Piston geometry, Transesterification