The present investigation is carried out on bi fuel mode fuelled with hythane as secondary fuel and diesel as primary fuel. Initially, run the diesel engine with pure diesel at various loads from no load to full load condition. Now the diesel engine is converted in bi fuel mode by injecting the hythane with the flow rates of hythane is 4, 5 litres per minute (lpm) from the inlet manifold and diesel as pilot fuel. In a bifuel mode with hythane10 at 5lpm showed improved thermal efficiency of 11.54% when compared with pure diesel operation. The hythane10 at 4lpm showed the reduction of NOX by 12.78% than the diesel operation. © IAEME Publication.