This study presents performance behaviors of a commercial diesel engine fueled with diesel and Jatropha based biodiesel (B100) at various loads (up to 100%) and compared using standard (conventional) and three new face profile designs (I, II & III) of piston rings. BTE of engine fueled with diesel increases 2-8% with new face profile design (III) of piston rings in comparison to standard (conventional) piston rings. BTE enhances 8-16% when engine is fueled with biodiesel using face profile design (III) on piston rings. Corresponding to increase in BTE, recorded reduction in BSFC (biodiesel) is 28-34%. Industrial application of the results of present study may be useful in saving and conservation of fuels.