A gasoline automotive engine is to be modified to burn kerosene-based fuel under a US Defense Advanced Research Projects Agency (DARPA) programme to develop a lightweight "heavy fuel" engine for the A160 Hummingbird rotary-wing unmanned air vehicle (UAV). A prototype engine will be ground tested next year.
Sonex Research has been awarded a $744,250 contract to apply stratified charge radical ignition (SCRI) technology to the 225kW (300hp) four-stroke engine powering the A160 technology demonstrator. Using less-volatile kerosene-based fuels such as JP5 and JP8 will reduce the hazards and logistics burden associated with gasoline. Converted gasoline engines are lighter than diesels, says Sonex.
Sonex has previously converted a small two-stroke gasoline engine to heavy fuel for the US Marine Corps' Dragon Drone UAV. The company will convert the engine from spark ignition to radical, or chemical, ignition using specially designed pistons. These feature micro-chambers around the combustion bowl that trap fuel and slow oxidation, forming highly reactive chemicals that act as catalysts for auto-ignition.
Source: Flight International
