An Experimental Study on the Working Stability and Combustion Characteristics of a Direct Injection Diesel Engine Operating on Multifuels

This paper presents the results of experimental studies carried out on a spark-assisted, direct-injection, diesel engine operating on methanol, ethanol and gasoline (all having low cetane numbers) as well as on diesel fuel. The key measures that ensure reliable ignition and stable flame propagation through the inhomogeneous mixture are the character and location of the fuel spray in the combustion chamber relative to the location of the spark in both the vertical and horizontal directions, the spark plug gap, and the timing of injection and spark. When these parameters are optimized, the engine runs smoothly over a wide range of speeds and loads. The ignition characteristics, rates of heat release, cycle-to-cycle variations, NOx emissions, and thermal efficiencies of the engine operating on these four fuels are analyzed and compared in detail.