How Can Anti-lock Braking System (ABS) Technology In Cars Work?
ABS prevents the wheels from locking up, thus avoiding uncontrolled skidding of the automobile and reduces the distance travelled without slipping.
Driving on expressways can be enjoyable and thrill-inducing, as many of you surely know. One gets to unleash a car’s full potential. The city streets keep us grounded, but as soon as you hit the highway, there’s no looking back. You’ll almost never see a car going below 100 km/hr.
The situation gets especially tricky during monsoons, as cruising in a car at such high speeds is the perfect recipe for a disaster if the roads are slick. Even so, it does occur, so what do you do in a situation on a slippery road whenever you have to suddenly apply the brakes of your car? Without an anti-lock brake system, the wheels of your car stop spinning and the car will begin to skid. You’ll completely eliminate control over the automobile and the results could be deadly.
Anti-lock braking systems (ABS) take plenty of the challenge from the sometimes nerve-wrecking event. In fact, on slippery surfaces, even professional drivers can’t stop as quickly without ABS as an ordinary automobile safety driver can with ABS.
What is Anti-lock braking system (ABS) in automobiles?
As its name suggests, the anti-lock braking system is a safety system in cars and other automobiles that keeps their wheels from locking up and helps their drivers to maintain steering control. Also known as anti-skid braking system sometimes, it enables the wheels of a vehicle to keep tractive contact with the ground so that they don’t go into an uncontrolled skid.
With ABS, you have more control on your vehicle during situations like sudden braking. Basically, it is designed to help the driver maintain some steering ability and prevent skidding while braking.
ABS Working principle
The fundamental concept behind anti-lock brakes is simple. It prevents the wheels from locking up, thus avoiding uncontrolled skidding. ABS generally offers improved vehicle control and decreases stopping distances on dry and slippery surfaces.
A skidding wheel (where the tire contact patch is slipping relative to the street ) has less traction (grip of the tire on the street ) than a non-skidding wheel. By way of instance, if your car drives over a road covered in ice, it is unable to proceed and the wheels will keep spinning, because no grip is present. This is because the contact point of the wheel is slipping relative to the ice.
ABS modifies the brake fluid pressure, independent of the amount of pressure being exerted on the brakes, to bring the rate of the wheel back to the minimal slip level that is mandatory for optimum braking performance.
ABS has four major components:
1) Speed Sensor
This sensor monitors the speed of each wheel and determines the necessary acceleration and deceleration of the wheels. It consists of an exciter (a ring with V-shaped teeth) and a wire coil/magnet assembly, which generates the pulses of electricity as the teeth of the exciter pass in front of it.
The valves regulate the air pressure to the brakes during the ABS action. There is a valve in the brake line of each brake that is controlled by the ABS. In the first place, the brake valve is open and it helps the pressure from the master cylinder to be transferred into the brakes. In the second place, the brake valve stays closed and pressure from the master cylinder to the brakes is constrained. In the third place, the valve releases some of the pressure on the brakes.
The next step is repeated until the car comes to a stop. The resistance that you feel when braking abruptly at high speeds is actually the brake valves controlling the pressure which has been transferred to the brakes in the master cylinder.
3) Electronic Control Unit (ECU)
The ECU is an electronic control unit that receives, amplifies and filters the detector signals for calculating the wheel rotational speed and acceleration. The ECU receives a signal from the sensors in the circuit and controls the brake pressure, according to the data which is examined by the unit.
4) Hydraulic Control Unit
The Hydraulic Control Unit receives signals from the ECU to apply or release the brakes under the anti-lock conditions. The Hydraulic Control Unit controls the brakes by raising the hydraulic pressure or bypassing the pedal force to decrease the braking power.
ABS in operation
While braking, if a wheel-locking scenario is detected or expected, the ECU alerts the HCU by sending a present and commands it to release the brake pressure, letting the wheel speed to increase along with the wheel slide to decrease. When the wheel velocity increases, the ECU reapplies the brake pressure and restricts the wheel slide to a certain level (Note: When the braking action is initiated, a slippage between the tire and the road surface in contact will occur, which makes the speed of the automobile different from that of the tire). The Hydraulic Control Unit controls the brake pressure in each wheel cylinder depending on the inputs in the system sensor. As a result, this controls the wheel speed. This process is repeated for the next braking operation.