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Technical Paper

JOHN DEERE 9000 SERIES COMBINES

1989-05-01
891389
John Deere 9000 combines are the result of a simultaneous engineering effort. New features, increased productivity, higher reliability, better serviceability, and safety result from customer surveys. A larger diameter cylinder/concave and new slope tolerant cleaning system increase capacity. Cab and controls offer improved visibility, comfort, handling and safety. Electronic governors improve engine performance. Power distribution gearcaes replace belt drives to improve reliability. A hydrostatic pump and motor control ground speed. The hydraulic system is controlled with hydro-electronic valves. A header disengage switch is located in the operator's seat.
Technical Paper

Noise Control Enclosure for an Electric Fan Motor

1989-05-01
891159
An air circulating fan motor located within the passenger compartment of an automobile was emitting an objectional noise. Both the level and frequency range of the noise contributed to the problem. Although the total Sound Power Level (SPL) at the passenger location was not expected to be reduced, due to the multitude of sources contributing, the goal of the program was to develop a noise control barrier for the motor which would eliminate the contribution of the motor to the total SPL. The first concern was to verify that a barrier would indeed eliminate the problem. This was accomplished by designing an ideal barrier for the motor. Even though this ideal barrier would not be amenable to a production solution. A nine dB reduction resulted from the ideal barrier and the program continued through the design and evaluation of a field usable barrier. This paper will present the details of the efforts completed during the development of the enclosure.
Technical Paper

An Investigation into the Significance of Infrasound in some Passenger Cars

1989-05-01
891158
During the last two decades there has been much interest in the effects of infrasound on people. This is partly due to assessments made by some scientists that infrasound could cause side-effects such as intestinal irritations,throbbing in the head,nervous breakdowns,certain allergies and other unpleasant phenomena of modern life found in industrial cities. With the possible effects on road safety this paper describes measurements of infrasound intensity in European passenger cars. It was found that infrasonic sound pressure levels (ISPL) were proportional to vehicle speed, window opening and vehicle size. Also driving with a fitted roof rack tended to increase ISPL by as much as 20 dB. It was also found that under most adverse driving conditions ISPL never exceeded 110 dB which is below the threshold to degrade human performance. It seems therefore that the original significance placed on infrasound in cars was overestimated.
Technical Paper

Simulation of Seat Ride Performance as Influenced by the Mechanical Impedance of the test Load

1989-05-01
891161
The ride performance of: two off-highway operator seats was simulated on a PC using TK Solver Plus™ and Tutsim™*. The narrow band random input acceleration to the model conformed to the requirements of the Class 1 Agricultural Tractor spectrum per SAE J1386 JAN86. The purpose of the study was to determine the influence of operator subject (test load) mechanical impedance on seat ride performance. Specifically is it feasible to replace human test subjects with a rigid mass or simplified impedance model? The results indicate that a rigid mass would result in much higher weighted rms acceleration (per J1013) than would a human subject. However, a single-degree-of-freedom (SDOF) seat load produced a seat response comparable to the response for a more complex two-degree-of-freedom (2DOF) model simulating human mechanical impedance up to 10 Hz.
Technical Paper

Optical Tuning of Adaptive Hydraulic Engine Mounts

1989-05-01
891160
Recent trends in lighter and smaller vehicles have motivated the application of adaptive hydraulic engine mounts for control of vehicle frame vibrations. This paper presents the results of a study on hydraulic engine mounts implemented on a light truck. The focus is on derivation of an optimal scheme for tuning the adaptive mounts. A simplified model of a vehicle engine suspension systems is derived. Simulations of receptance and accelerance are conducted to provide insight into mount tuning. An optimal mount tuning function is derived based on maximization of kinetic energy in the bleed fluid loop. Peak accelerance is attenuated by 18 db concurrently with peak receptance attenuation of 6 db. A general scheme for formulation of the tuning is presented.
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