Reduction of Vibrations Using Variable Damping Torsional Dampers for Smart Vehicles Using Real-Time Intelligent Smart Fluid Controls

Vibrations are periodic or random oscillations that occur about an equilibrium point. Vibrations occur as an undesirable effect in many engineering applications like heavy machinery and tall structures. Many methods have been formulated to control and minimize the effects of vibration, including dampers, vibration absorbers and isolators. While dampers attempt to dissipate vibrational energy quickly and thus decrease its amplitude, vibration absorbers attempt to restrict vibration to a secondary system such that it does not affect the crucial components. A passive vibration absorber suppresses vibrations from a source when it is tuned to the right frequency. However, if the exciting frequency varies, the vibration of the entire system may increase significantly. Thus, an important and desirable characteristic of vibration control devices is the ability to be tuned to a wide range of frequencies. This can be achieved using active or semi-active vibration absorbers. While active vibration absorbers are effective in eliminating vibrations to a high level of accuracy, which may be of use in highly sensitive equipment, most applications require a more energy-efficient and simpler setup that can effectively reduce the damage vibrations may cause. Semi-active vibration absorbers are effective and dependable on this front. They consume less power, can be tuned to a wide range of frequencies and can also behave as a passive component in case of loss of power. The paths to attain a feasible semi-active absorber are few. This includes utilizing systems with varying damping ratio, varying stiffness and varying mass distributions. The control of these variable properties should be easy, fast and should consume minimum power. Smart materials are ideal candidates here. This work mainly focuses on the vibration reduction of crankshaft of internal combustion engine using magnetorheological fluid. Variable damping characteristics are possible with the help of magnetorheological fluid by varying the amount of the magnetic field across the fluid containing magnetizable particles. It is observed that both radial and axial reduction of vibration amplitude is possible up to 50% using MR-based torsional vibration dampers in crankshaft of internal combustion engine.