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JP-8 Conversion Kit for Small Spark Ignition Gasoline Engines

Description:

TECHNOLOGY AREA(S): Ground Sea 

OBJECTIVE: To develop a retrofit kit that converts small, spark ignition gasoline engines to operate on military jet fuel for small unmanned Army ground vehicles. 

DESCRIPTION: Current and future unmanned and autonomous systems require and will require small to medium sized power sources to meet mission objectives requiring both on-board electric power and propulsion power for meeting mobility requirements. Such vehicles could be an integral part of the future ground force fighting capability of the Army as such unmanned and autonomous systems are developed and integrated into the manned ground force fleet. A portion of these vehicles require a power level that is outside the commercial market availability for small and lightweight diesel engines. It is common at power levels approximately less than 25 brake horsepower that commercial gasoline engines are the only viable internal combustion engine that can provide the necessary vehicle power for both meeting mission objectives and propulsion system weight and volume targets, but such engines are not compatible with military jet fuels (F-24 and JP-8). The objective of this topic is to develop an affordable kit for converting a baseline spark ignition gasoline engine to operate on military jet fuels that has minimal complexity and cost while not sacrificing the performance of the baseline engine. Positive features of such a kit includes minimal part count, minimal use of special tools to install the kit, and a cost target not to exceed 20% of the baseline engine purchase price. 

PHASE I: Identify and assess possible retrofit kit options for a small baseline spark ignition gasoline engine with a rated power of less than 25 brake horsepower. Such an effort should include any necessary analysis and bench testing to support the selection of a viable retrofit kit that maintains a wide open throttle (full load) torque-speed curve within 5% of the commercial baseline product and maintains brake specific fuel consumption throughout the torque-speed curve within 10% of the commercial baseline product while operating on military jet fuels. The outcome of this phase should be selection of a retrofit kit for evaluation in phase II. 

PHASE II: Demonstrate and validate the performance of the chosen phase I candidate retrofit kit on the phase I selected baseline spark ignition gasoline engine using military jet fuel. Such a demonstration should focus both on the performance of the retrofit kit to sustain the base engine performance including the torque-speed curve within 5% of the commercial baseline product and brake specific fuel consumption throughout the torque-speed curve within 10% of the commercial baseline product and also maintain the commercial reliability/durability of the kit. 

PHASE III: Develop a retrofit kit that could be readily used for both military and commercial base spark ignition gasoline engine conversion purposes. It is envisioned that this technology could be beneficial to the military in providing lightweight, inexpensive, and jet fuel tolerant small engines for unmanned ground vehicles and also could support an alternative engine option for commercial airport use where jet fuel is readily available. 

REFERENCES: 

1: P. Schihl and L. Hoogterp-Decker, "On the Ignition Behavior of JP-8 in Military Relevant Diesel Engines", SAE International Journal of Engines, 4(1): 1-13, 2011.

2:  J. Schmitigal and J. Tebbe, "JP-8 and other Military Fuels", www.dtic.mil/get-tr-doc/pdf?AD=ADA554221

3:  P. Schihl, L. Hoogterp, and H. Pangilinan, "Assessment of JP-8 and DF-2 Evaporation Rate and Cetane Number Differences on a Military Diesel Engine", SAE Paper 2006-01-1549, 2006.

KEYWORDS: Jet Fuel, Jet Fuel Conversion Kit, Heavy Fuel Engine 

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