Electric Parking Brake (EPB) working explained
The electric parking brake or the EPB is an advanced version of a conventional parking brake or handbrake. Sometimes, people also refer to this system as 'Electronic Parking Brake'. Technically this system is a sub-part of more advanced 'Brake by Wire' system.
The main function of parking brakes is to avoid the motion of the vehicle when parked. In addition, these brakes also play an important role in avoiding the backward motion of vehicles which resumes moving on a slope. Generally, parking brakes operate only on the rear wheels of a vehicle.
How Electric Parking Brake works:
Conventional parking brakes employ a cable that connects handbrake lever and brake shoes. When the driver operates the lever, the tension in the cable increases thereby forcing the brake shoe (or pads) on brake drum (or disc). Thus, wheels cannot move further.
However, in Electric Parking Brake, no such cable connection exists. Instead, it works with the help of following main components:
- Electronic Brake Module
- An actuator or electric motor
- Electric Switch in cabin
When the driver operates the switch, it sends a command to Electronic Brake Module which senses that parking brakes are required to be operated. Later, this module commands the actuators or electric motors installed in the brake calipers to operate. Thus, brake pads are forced on the disc thereby restricting the movement of wheels.
Due to the use of electronic components, the operation of this system is almost instantaneous and efficient. Also, it improves the reliability of braking because of the absence of a mechanical connection. This brake deactivates automatically when the driver presses the accelerator pedal. Some vehicle manufacturers also integrate Hill Start Assist function with this system.