Analysis and simulation of centrifugal pendulum vibration absorbers

Abstract: When environmental laws are constricted and downsizing of engines has become the reality of the vehicle industry, there needs to be a solution for the rise in torsion vibrations in the drivetrain. These increased levels of torsion vibrations are mostly due to excitations from the firing pulses, which in turn have become increased due to higher cylinder pressures. One of the solutions for further dampening the system is to add a centrifugal pendulum absorber to the flywheel, and predicting the behaviour of such a device has become imperative.The intent of this thesis is to create a model that will accurately emulate the effectiveness and functionality of a centrifugal pendulum absorber, so that it can be used in simulations to predict vehicle behaviour with its addition. To validate the model, a comparison is made between simulated results, using the model created in Adams/Car and Matlab, and road measurements conducted using a prototype acquired by the industry.The results from the simulations show that, with existing theory on the subject and software provided by Scania, an accurate model can be created. The reduction of torsion vibrations is evident, and the model’s behaviour correlates to that of the prototype.Future work on the subject requires a larger insight into pendulums tuned to multiple orders, and an extension of the model geometry would be advantageous.