Under Armor Auxiliary Power Unit

Urider Armor Auxiliary Power Unit by Staff Sergeant Robert Bialczak (MWBL) and Lieutenant Colonel Jackie Hamilton (TECO) In May of 1993, the Mounted Warfighting Battlespace Lab (MWBL), Fort Knox, Ky., at the direction of then U. S. Army Armor Center Commander, Major General Paul Funk, led a coordinated effort to detennine the levels of technology available to produce an under annor auxiliary power unit (UAAPU), conduct afield demonstration of that technology, and report on the results. The intent of the project was to determine if there could be any value in integrating U AAPU into the mounted force. The M I Abrams force is not equipped with auxiliary power units. When the vehicle is at rest, such as in defensive positions, the main engine is normally shut down while the electrical systems must remain in a power-up state, and the only source for this power is the vehicle batteries. Since the electrical systems will drain batteries quickly, thus endangering crews by failing to achieve main engine start and power loss, there is a strong need for on-board power generation. The MWBL sent out an initial request for information to the civilian business community in June 1993 to canvass for their input on U AAPU technology. Four industries have since invested time, effort, and financial resources, each producing a U AAPU prototype for demonstration. The basic decision (made early in the program) regarding integration was that various corporations would be offered the opportunity to place their UAAPUs in the chassis of demonstration MIAls, and government offices (Test and Evaluation Coordination Office (TECO), Ft. Knox and PM-Abrams) would design and approve the interfaces of those systems 46 into the vehicle. Three ideals guided this government integration: e All integrations would be similar to the maximum extent possible. This meant that such things as fuel supply wold be from the vehicle's rear fuel tanks, bleed air would be introduced to the NBC system through the existing ducting, etc. eThe integration would utilize existing MILST ANDARD materials to the maximum extent possible, and specifically items which were already installed on the M I A I tank. This was. successful to the extent that only four items are not part of the tank - NICAD batteries, NICAD battery connectors (both of which are on all Army and other types of aircraft), the fuel meters which gather data on consumption and the flexible metal tubing utilized to duct bleed air to the NBC system. Such items as fuel lines and wiring harnesses are constructed of the same materials and in the same manner as those on the engine of the MIAl. eThe integration would not intrude into the operating envelope of the system. This means that all power into the vehicle from batteries and U AAPU would be through the existing battery negative and positive buss bars. This meant that the existing charging system regulators and safety features continue to be utilized. All signals to control the UAAPUs were taken from the test jack (TJ) on the hull network box. Due the configuration of U. S. Army test equipment (STE-ICE and DSETS), test jacks are included on major network boxes. When a signal is generated inside a network box to do something ("turn on NBC," etc.) that signal goes to two jacks, the one I

I UXILlARY POWER UNIT

ESDMAlED GROSS COSIS4JONGS (Pw IMk - 20 "I'.., PEACETlME: Fuel $ 16,900

Maintenance 200,200 Engine $359,100 Fuel, maintenance, and engine savings plus reduced logistic pipeline. J....-__