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Technical Paper
David Copley, D. W. Herrin, Harvind Raman, Jiantie Zhen
Properly characterizing input forces is an important part of simulating structure-borne noise problems. The purpose of this work was to apply a known force reconstruction technique to an earthmoving machinery cab to obtain input functions for modeling purposes. The technique was performed on a cab under controlled laboratory conditions to gain confidence in the method prior to use on actual machines. Forces were measured directly using force transducers and compared to results from the force reconstruction technique. The measured forces and vibrations were used as input power to an SEA model with favorable results.
Technical Paper
Alireza Farjoud, Florin Marcu, Eric Schumann
This paper presents a novel 6-DOF multi-physics model of a cab suspension system. The model consists of a cab with six degrees of freedom supported by four fluid filled viscous mounts. In the literature, to the best of the authors' knowledge, all 6-DOF cab models have simplified fluid filled mounts as spring damper combinations. In its best case, a nonlinear stiffness relationship is allowed in the simplified models to capture the nonlinear behavior of the mounts and include geometric constraints and hard-stops. The novel model presented in this paper, however, includes a multi-physics model of the mounts. Each mount is represented by a molded assembly, two fluid chambers, a fluid track that connects the two chambers, and a gas chamber. Each mount can be pressurized or vented. A simple cavitation model is also used as an indicator of fluid cavitation in each mount.
Technical Paper
Nicola Terdich, Ricardo F. Martinez-Botas, David A. Howey, Colin D. Copeland, Aaron Costall
Turbocharged diesel engines are widely used in off-road applications including construction and mining machinery, electric power generation systems, locomotives, marine, petroleum, industrial and agricultural equipment. Such applications contribute significantly to both local air pollution and CO₂ emissions and are subject to increasingly stringent legislation. To improve fuel economy while meeting emissions limits, manufacturers are exploring engine downsizing by increasing engine boost levels. This allows an increase in IMEP without significantly increasing mechanical losses, which results in a higher overall efficiency. However, this can lead to poorer transient engine response primarily due to turbo-lag, which is a major penalty for engines subjected to fast varying loads. To recover transient response, the turbocharger can be electrically assisted by means of a high speed motor/generator.
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