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This paper describes the design, implementation and testing of crankshaft-mounted pendulum absorbers used for reducing vibrations in a variable displacement engine. The engine can run in V8 and V4 modes, and without absorbers it experiences significant vibration levels, especially in V4 idle. The absorbers are tuned to address the dominant second order vibrations, and are slightly overtuned to account for nonlinear effects. The absorbers were designed to replace the large counterweights at the ends of the crankshaft, and thus serve for both balancing and vibration absorption. The engine was placed in a vehicle and tested for vibration levels at idle under various load conditions, and these results were compared with results obtained from a similar vehicle without absorbers. The tests demonstrate that these absorbers offer an effective means of vibration attenuation in variable displacement engines.

A device has been designed and built to allow one to systematically investigate the dynamical behavior of a wide variety of torsional vibration absorbers (TVAs). These are devices that can passively absorb the torsional vibration of a wide range of rotating systems. The testing device allows different operating conditions to be studied and similarities and discrepancies between theoretical predictions and experimental results can be made. The manuscript emphasizes the design and capabilities of the device and discusses the instrumentation of the system. It also presents a limited number of experimental results along with the associated theoretical predictions.

In this paper results are presented from a study that investigates the use of centrifugally driven pendulum vibration absorbers for the attenuation of engine torsional vibrations. Such absorbers consist essentially of movable counterweights whose center of mass is restricted to move along a specified path relative to the rotational frame of reference. These devices are commonly used in light aircraft engines and helicopter rotors. The most common designs use a circular path for the absorber, tuned to a particular order of rotor disturbance, although more recent developments offer a wider variety of paths. Our goal here is to evaluate the system performance for a range of path types with different types of tuning. This analytical study is carried out for a simple mechanical model that includes a rotor and an absorber riding along a quite general path. Approximate solutions are obtained using a perturbation scheme and compared with detailed computational results.

Squeak and rattle has become a primary source of undesired noise in automobiles due to the continual diminishment of engine, power train and tire noise levels. This article presents a finite-element-based methodology for the improvement of rattle performance of vehicle components. For implementation purposes, it has been applied to study the rattle of a glove compartment latch and corner rubber bumpers. Results from the glove compartment study are summarized herein. Extensions to other rattle problems are also highlighted.