Variable Rate Pedal Feel Emulator Designs for a Brake-By-Wire System

An important element of a brake-by-wire system is the pedal feel emulator. This device is tuned for each vehicle application to provide the desired pedal force/travel relationship while operating the brake system in the normal powered mode. The two designs examined apply to a hydraulic based brake-by-wire system and are used in conjunction with a master cylinder to meet failed power braking requirements. Both designs use uniquely different spring technologies to provide a variable rate curve to simulate the pedal feel characteristics of a conventional vacuum boosted brake system.