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The performance of battery-capacitor combinations for diesel engines starting was investigated using computer simulations. The system was comprised of a diesel engine, starting motor, one, two, or three batteries and an electrochemical capacitor, which is sometimes called a supercapacitor or ultracapacitor. Circuit models of each component were developed and used to examine system performance. Results demonstrate that adding a capacitor to the starting system can increase the peak rotation rate of the engine and in addition, reduce starting system mass and volume. Significantly, system effectiveness is often greater if the capacitor is rated for and operated at a voltage higher than the battery. This permits use of a smaller, lower-cost capacitor. The voltage seen by the starter in such mixed-voltage systems is below its rating.

This paper reports experimental results of engine starting trials conducted by the Army on common military vehicles using capacitor power sources. Improved starting performance can be obtained with the use of a capacitor, particularly at low temperatures. Power delivered by battery-capacitor systems are presented and compared to battery-only systems. Weight, volume, life, and cost comparisons for the two systems are given. A preliminary life-of-system cost analysis is presented and shows the potential for substantial cost savings to the Army from the use of capacitors in its vehicles.

Bearing design optimization is dependent on being able to fully characterize the bearing operating environment. While much is being written about the need for optimization, the need for better tools to characterize the operating environment is painfully evident. This paper introduces the use of Signature™ bearings as applied to the characterization of operating environments using tapered roller bearings.

This paper examines surface roughness effects and the inaccuracy introduced by changes in roughness resulting from normal run-in. While factors such as the ‘Oil Film Thickness to Composite Surface Roughness ratio’, Lambda, are being used, their reliability is dependent on the accuracy of the input data. Studies were conducted on cylindrical roller bearings (40 mm bore) at two calculated Lambda levels, 1.5 and 0.04, to evaluate changes in surface texture during short running time increments. The conclusion of the study offers recommendations for improving the methods used to predict bearing fatigue life.