Magnetorheological (MR) piston assembly with primary and secondary channels to improve MR damper force

A magnetorheolgical (MR) damper includes a piston assembly having a primary channel disposed along a longitudinal axis and contained in a cylinder. MR fluid is also contained in the cylinder. The piston assembly having a primary channel, or primary channel MR piston assembly, includes a piston body having a first end axially spaced from a second end and defining a hole therethrough. The primary channel is defined in an outer body surface of the piston body from the hole at the second end to a coil groove in the outer body surface about the axis. A secondary channel is defined in the outer body surface from the coil groove towards the first end to improve MR damper force performance at low primary channel MR piston assembly velocities.