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IMPLEMENTATION OF A SECOND GENERATION SOUND POWER TEST FOR PRODUCTION TESTING OF EARTHMOVING EQUIPMENT Caterpillar has developed an automated sound power measurement system that measures construction equipment sound levels before they leave the assembly plant. This paper describes the test system and gives the results of verification tests conducted at various manufacturing plants around the world. It was concluded that the new system allows Caterpillar to quickly and accurately acquire the data necessary to assure that their product meets its noise requirements.

The Challenger 65 agricultural tractor combines the best features of current four wheel drive machines; speed, on-road mobility, and operator comfort with the well recognized advantages of track-type machines; tractive efficiency and reduced soil compaction.

The stability and dynamic characteristics of frictioninduced vibrations in a simplified aircraft brake model are investigated. A finite element model equipped with nonlinear frictional contact algorithm is used. The constitutive model of the interface is based on an extended version of the Oden-Martins law [1]. The interface material constants are obtained via asperity-based homogenization methodology from the profilometric information on the surface. Initial uncoupled analyses are performed to identify the basic dynamic modes of the model. Frequencies of normal vibrations of the model are found to be dependent on the interface stiffness and the piston pressure. To study the dynamic behavior of the system, its transient response is computed after a perturbation of the steadystate sliding position. It is found that, while the vibrations are subdued in some cases categorized as stable, they grow in other, unstable cases.

Oil carryover is present in all pneumatic systems where the compressed air is generated by oil lubricated compressors. With the increased use of electronic and small orifice components on trucks and coaches, the problem of contamination and failure related to oil carryover in the compressed air system has increased. Even though the rate of oil carryover out of the compressor has improved over recent years, problems persist. This paper will describe how the oil is transported out of the compressor, the various states oil is generated including vapor pressure profiles and size distribution of the condensed aerosols. Also reviewed is the oil removal effectiveness of various components downstream of the compressor. A model of oil liquefaction from vapor and aerosol states will be presented. The effect of liquefied oil combined with other contaminates in the pneumatic system and various design criteria for downstream equipment will be discussed.

In 1998, light trucks accounted for over 48% of new vehicle sales in the U.S. and well over half the new Light Duty vehicle fuel consumption. The Light Truck Clean Diesel (LTCD) program seeks to introduce large numbers of advanced technology diesel engines in light-duty trucks that would improve their fuel economy (mpg) by at least 50% and reduce our nation's dependence on foreign oil. Incorporating diesel engines in this application represents a high-risk technical and economic challenge.