Temperature Estimation in a Magneto–Rheological Damper

Magneto-rheological dampers are employed in the automotive industry to control the vehicle dynamics by modulating the damping characteristics of the suspension system; these devices rely on a smart fluid which can change its viscosity when subjected to a magnetic field. The viscosity of this magneto-rheological fluid is significantly dependent on the operating temperature; this phenomenon is particularly critical in the automotive field since the working conditions span a wide range of temperatures and, furthermore, a commercial vehicle cannot be equipped to directly measure the temperature of the fluid. This article proposes a methodology for the temperature estimation which exploits the thermodynamic relationship between the resistance of the electrical circuit of the device and the temperature of the magneto-rheological fluid.