Evaluation of heavy fuel engines for small unmanned air vehicles.

摘要

Man-portable Small Unmanned Air Vehicles (SUAVs) could be used by individual Army units for surveillance. Two cycle, hot surface ignition, Internal Combustion (IC) engines are ideal for these vehicles because of their high power-to-weight ratios. Today's military supply strategy requires these engines to operate on heavy fuel. Currently, small heavy fuel IC engines with automatic controls are not commercially available. DARPA is developing mission specific engines to meet requirements for Class I and II UAVs. Performance evaluation techniques and propeller testing results for two technology demonstration engines are provided in this thesis. These engines produced greater than anticipated horsepower. The DARPA engine Power Specific Fuel Consumption values were 29% below the 1.0 lb/hp-hr goal. Both engines require control algorithm development to minimize restarts and subsequent tuning. Further reduction of fuel oil content is also needed. Exergy analysis and combustion modeling techniques for future engine and fuel optimization are also discussed.