Development of Multi-Fuel Spark Ignition Engine 2004-32-0038

This study investigates the performance of a rope start two-stroke outboard engine, capable of running on multi-fuel, primarily focusing on JP5/8. This engine would be predominantly used worldwide by all departments of the US Military and Special Forces. A two cylinder, direct injected, 30 HP engine was used for research with ongoing development being carried out on larger motors, ranging to 250 HP. The investigation includes the performance characteristics of JP-5/8, gasoline, diesel, kerosene, ethanol and bio-diesel as a fuel, essentially concentrating on power, torque, effects of varying compression pressures on combustion characteristics and soot deposits, detonation characteristics of different fuels, behavior in stratified and/or homogenous combustion and cold start of the engine at temperatures of 0° F.

The development of specialized marine engines is in response to a recent directive by the Department of Defense stating it will cease the transportation of gasoline on ships or aircraft by 2010. Other countries are expected to follow. Compatibility of an engine with JP5/8, kerosene or diesel enhances the horizon of engines operating in a variety of applications due to the low volatility of such fuels which in turn facilitates storage, transportation and handling. These kinds of engines are also beneficial in military operations where the type of fuel available is uncertain.

Further research is being carried out for increasing the spark plug life with these fuels, lowering the intensity of knock by changing the design of the engine, reducing the particulate size in exhaust, minimizing the soot deposits in the exhaust manifold, and at the propeller where the soot sediments at the opening and thus changing the back pressure in the exhaust pipe.