QUESTION #393

What are the advantages of ABS braking systems compared to other hydraulic braking systems?

Asked by: Pritesh Vadolia

Answer

The advantages of ABS brakes (anti-lock braking system), are just as the meaning of their acronym implies, they eliminate or greatly reduce the possibility of brake lock up and therefore provide a better chance of steering out of trouble.

Conventional hydraulic brakes work by using a cylinder (actuator), which squeezes brake calipers together around the wheel's rotor when the brake petal is depressed. Difficulties arise with these conventional brakes if the road is slick and the driver executes a panic stop. Under these conditions the wheels may lock up and the tires run the risk of losing their grip. When tires lose their grip of the road, there is a good chance that the car may go into an uncontrolled spin. This is why drivers in older vehicles have been taught in the past to pump brakes when on icy roads.

ABS brakes were designed to combat the problem of tire lock up and uncontrolled spins. Since brakes are most effective at slowing the car at a point just before wheel lock up, a system that provides for wheel braking while preventing wheel lock up is very desirable.

Anti-lock brakes do just this by using a computer processor to monitor and control the application of the brakes. At braking, the processor monitors rpm and braking pressure on each of the vehicle's wheels. With this information, measured amounts of pressure are sent to each wheel in the form of hydraulic pulses of pressure to the calipers. These pulses achieve the desired braking pressure without allowing the wheels to lock up.
Answered by: Stephen Portz, Technology Teacher, Space Coast Middle School, FL