A brake pedal emulator for a brake-by-wire system of a vehicle extends and connects between a support structure and a brake pedal operatively engaged to the support structure. The brake pedal emulator includes a hydraulic cylinder having a magneto-rheological hydraulic fluid and an electrical element configured to carry an electrical current for controlling a viscosity of the magneto-rheological hydraulic fluid and thereby controlling a first force exerted by the hydraulic cylinder when actuated by the brake pedal.