Theory and Design of Pendulum Dampers
There is sometimes a need to damp the camshaft torques described in Chap. 9. The reactive pendulum damper described below has been described in the literature. In the past it was used to damp the torsional vibrations of crankshafts used in both automotive and aero engines, which had long crankshafts that lacked torsional stiffness. The theory on which it is based is also widely available in the literature. However, both the basic vibration theory and a description of the damper are given as it is relevant to the subject considered in this book. The advantage of this damper is that it is almost purely reactive and therefore dissipates very little energy. An incorrectly designed or significantly worn damper can exacerbate the problem rather than alleviating it. The maximum damping torques generated by the damper while retaining linear motion must be equal to the torques causing the vibration. It is therefore necessary to ensure the damper has sufficient capacity. An oversize damper will add additional inertia to the engine which will cause slower transient response and will reduce the effective power available when engine speed is increasing.
KeywordsEngine Speed Angular Displacement Gear Tooth Polar Moment Valve Timing
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