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The main issues related to the vibration response and acoustic noise emission of a new liquid fuelled fuel cell APU (auxiliary power unit) system are discussed and analyzed. These problems are being addressed in an on-going research project. The APU is comprised of several critical subsystems including the fuel processing system, fuel stack, heat exchanger, compressor, as well as high-pressure and low-pressure components. The vibration concern deals with the design of a two-stage isolation mount system to shield these critical parts from the shock and steady-state dynamics coming through the truck frame during on-road traveling conditions. A lumped parameter dynamic model is formulated for use in optimizing the mount stiffnesses and locations. Acoustic concerns are primarily related to exterior noise levels when the truck is at a rest stop. To address those issues, experimental studies are conducted to quantify the main sources and paths for noise.

Surrogates for JP-8 have been developed in the high temperature gas phase environment of gas turbines. In diesel engines, the fuel is introduced in the liquid phase where volatility plays a major role in the formation of the combustible mixture and autoignition reactions that occur at relatively lower temperatures. In this paper, the role of volatility on the combustion of JP-8 and five different surrogate fuels was investigated in the constant volume combustion chamber of the Ignition Quality Tester (IQT). IQT is used to determine the derived cetane number (DCN) of diesel engine fuels according to ASTM D6890. The surrogate fuels were formulated such that their DCNs matched that of JP-8, but with different volatilities. Tests were conducted to investigate the effect of volatility on the autoignition and combustion characteristics of the surrogates using a detailed analysis of the rate of heat release immediately after the start of injection.

A liquid fuelled, fuel cell auxiliary power unit (APU) can provide efficient, quiet and low pollution power for a variety of applications including commercial and military vehicles. Truck idling regulation, customer comfort or military “stealth” operation by using electrical power, require a device disconnected from the main diesel engine. The power can be utilized for air conditioning as well as other auxiliary systems found on board commercial trucks for driver comfort. In a military vehicle, this regulated power could be supplied to telecommunication and other computer equipment required for military operations. A system designed to be an add-on or retrofit solution using alternative fuel can have the potential to meet these requirements on the hundreds of thousands of existing vehicles currently in service or as optional equipment on a newly procured vehicle.

To overcome a vehicle's tractive resistances and accelerate its gross weight, the propulsion system must have enough energy available at the diameter of its traction road wheel/sprocket-track as tractive effort. The tractive effort of the wheel/sprocket must balance or exceed that of vehicle's tractive resistances. The tractive resistances are comprised of wheel-terrain rolling friction, also called rolling resistance, R R , ambient air/wind resistance, R A , vehicle mass-slopped terrain gradient resistance, R G , and additional accelerating force demand from the propulsion engine to overcome the rotating element masses of the engine transmission gear and wheel inertia forces. Each of the mentioned tractive resistances and the rotating elements' inertia shall be fully studied and will be the subject of the next papers in this series.

This paper presents the results of an experimental investigation on a single cylinder engine to validate a two-component JP-8 surrogate. The two-component surrogate was chosen based on a previous investigation where the key properties, such as DCN, volatility, density, and lower heating value, of the surrogate were matched with those of the target JP-8. The matching of the auto-ignition, combustion, and emission characteristics of the surrogate with JP-8 was investigated in an actual diesel engine environment. The engine tests for the validation of the surrogate were conducted at an engine speed of 1500 rpm, a load of 3 bar, and different injection timings. The results for the cylinder gas pressure, ignition delay period, rate of heat release, and the CO, HC, and NOx emissions showed a good match between the surrogate and the target JP-8. However, the engine-out particulate matter for the surrogate was lower than that for the JP-8 at all tested conditions.

This paper investigates the effect of boost pressure and intake temperature on the auto-ignition of fuels with a wide range of properties. The fuels used in this investigation are ULSD (CN 45), FT-SPK (CN 61) and two blends of JP-8 (with CN 25 and 49). Detailed analysis of in-cylinder pressure and rate of heat release traces are made to correlate the effect of intake pressure and injection strategy on the events immediately following start of injection leading to combustion. A CFD model is applied to track the effect of intake pressure and injection strategy on the formation of different chemical species and study their role and contribution in the auto-ignition reactions. Results from a previous investigation on the effect of intake temperature on auto-ignition of these fuels are compared with the results of this investigation.

Battlefield delivered fuel (jet and diesel) with required security, storage, transport, and dispensing equipment is estimated to cost $418/gallon [ 1 ], thus the need for very fuel efficient light weight engines for repower and future vehicles is critical. The U.S. Army RDECOM TARDEC Small Business Innovative Research (SBIR) Program funded Advanced Engines Development Corporation (AED) for the exploration, development and application of advanced diesel engine technologies and to incorporate these technologies into demonstrator engines, a 4-cylinder and V-8's. AED based these demonstrators on current production GM gasoline engine diesel conversions employing commercial-off-the-shelf (COTS) advanced diesel systems and engine components.

There is a need for high efficiency radiators in liquid cooled military vehicles. It is obvious that the new system should be better than the current Al radiators in terms of thermal performance, military robustness, size, weight and easiness of mass production. For the last ten to fifteen years, a search for new materials has been ongoing. One of the best current candidates is a pitch-based carbon foam that exhibits a superior thermal performance, but with inferior mechanical performance. While developing carbon foam systems, with the intent of overcoming its seriously low mechanical strength, it was also discovered that another serious concern emerged, namely the difficulty in joining, bonding and sealing the carbon foam to the same, or dissimilar material, such as metal or ceramic. This paper presents results of our first stage effort in strengthening carbon foam under an SBIR program funded by the National Automotive Center (NAC) at TACOM, Warren, MI.