BWIGroup, a leading global supplier of ride control systems, now has more than 10 years production experience with its MagneRide magneto-rheological damper technology. Introduced in North America in model year 2002.5 and following its model year 2006 European introduction, MagneRide is now available on many vehicles around the globe.
MagneRide consists of four monotube dampers, a sensor set and an on-board Electronic Control Unit (ECU). The magneto-rheological (MR) fluid used in the dampers is a suspension of magnetically soft (easily, but temporarily magnetised) iron particles in a synthetic hydrocarbon base. The damper piston contains an electromagnetic coil that can generate a variable magnetic flux across the fluid passages. When the coil current is off, the MR fluid is not magnetized, the iron particles are randomly dispersed within the fluid, and the fluid behaves like conventional hydraulic oil. When the coil is energized, the magnetic field causes the particles to align into fibrous structures in the direction of the magnetic flux. The strength of the bond between the particles in the structures is proportional to the strength of the magnetic field, so changing the current provides real-time variable damping with a very large range of force variation. The result is a system that outperforms conventional variable damping systems, but without the complex electro-mechanical valves used in those systems. Compared to other, valve-based technologies, MagneRide achieves a much broader damping force range and responds much more rapidly without generating noise.