Advanced Glow Plug for Heavy Fuels Applications

With current DoD goals of switching to a common battlefield logistics fuel, there is a significant push to develop technologies that allow small, high-powered engines such as used in unmanned aerial, marine, and ground vehicles, typically fueled by volatile fuels such as gasoline, to operate on heavy fuels such as JP-8. In this paper, the feasibility of catalytic glow plugs as an enabling component for the use of heavy fuels both as a retrofit to existing engines as well as new engine designs is demonstrated. Compared to standard spark igniters and non-catalytic glow plugs, the use of catalytic glow plugs will provide benefits including lower required compression ratio, improved igniter life, reduced energy requirements, and overall reduction in system weight and size. The catalytic glow plugs were shown to have a significant increase in surface temperature (180+°C) with impingement of a fuel spray and this increase was maintained over many cycles of impingement. Engine testing demonstrated the use of catalyst-allowed stable engine operation at reduced power requirements with durability exceeding 150 hrs. This technology would allow the use of logistic heavy fuels in small engines, while potentially reducing power supply weight and engine complexity and weight, both of which would allow greater range and/or payload capacity.