水素による超小型レシプロエンジンの試運転

抄録

Realization of reliable hydrogen combustion aero engines enables small UAVs(Unmanned Aerial Vehicles) to choose various types of power sources. Some trial runs of a micro reciprocating engine with hydrogen fuel were conducted. We used an FG-11 4-stroke gasoline engine for radio-controlled model airplanes, which have a displacement of 10.9 cm³. The engine showed excellent startability. Hydrogen-air premixture immediately ignited after supplying hydrogen fuel. When the equivalence ratio of the premixture was under 0.2, the continuous operation was achieved. At higher equivalence ratio, the engine speed gradually decreased, and it stopped eventually. Another type of lubricant which have higher flash point was used to prevent burning itself, but the problem was not resolved. The temperature distribution near the combustion chamber was increased when stopping. This suggests the clearance between piston and cylinder becomes not appropriate at higher equivalence ratio.