Currently, no light-weight production direct fuel injection systems exist that are appropriate for small UAV heavy fuel engines. JM Harwood identified this as the highest priority technology gap in the development of small heavy fuel UAV engines. A light-weight DFI system which pressurizes the fuel internal to the injector has been demonstrated.
JM Harwood’s current efforts are focused on a bolt-in, heavy fuel replacement for the 6 hp 3W-56 gasoline engine used in the g-MAV / Class I.
The Army Research Laboratory funded effort will both (a) demonstrate the miniature DFI system and (b) gather heavy fuel combustion data in both low and high compression ratio engines.
While the 6 hp XO-3 is currently JM Harwood’s primary focus for heavy fuel engine development, larger and more fuel efficient engines are being developed.