Increasing the efficiency of a diesel engine running on biodiesel through butanol fumigation

ABSTRACTA single-cylinder, direct-injection diesel engine was tested with regular diesel oil, neat Jatropha biodiesel, and biodiesel with butanol injection into the inlet manifold. An engine fueled with neat biodiesel showed 5% reduction of the fuel conversion efficiency and 17% increase in specific fuel consumption relative to diesel oil. With butanol injection at a rate of 25% of the total fuel consumption, the efficiency was equivalent to that of diesel oil and specific fuel consumption was less than that of neat biodiesel. Engine emissions with biofuel were improved except for carbon monoxide and unburned hydrocarbons. It was concluded that the diesel engine can operate on the neat biofuel (biodiesel plus alcohol) with the fuel conversion efficiency equivalent to that of the diesel oil.