ABS Brakes
ABS brakeshave become a common feature on vehicles of all sizes. The reason behind this is the safety improvement that an antilock brake system represents over the traditional brake configuration. During hard braking, the enhanced mechanism allows wheels connected to the system to maintain road friction, preventing a vehicle from skidding out of control. What makes this possible is a computer unit and a solenoid and pump modulator that can give even an inexperienced driver more control behind the wheel during emergency situations.Main ABS componentsA vehicle with ABS comes equipped with two or four wheel speed sensors-depending on the vehicle model-mounted somewhere near the wheel assemblies. Each sensor works in conjunction with a sensor rotor, a toothed wheel that rotates along with the wheel and tire. Thus, the sensors are able to send a continuous electrical signal to the ABS control module or computer with wheel speed information. The computer then compares each signal for frequency.Not far from the computer, an electro-hydraulic modulator seats patiently waiting for any orders from the control unit. This modulator connects to the wheels through a series of hydraulic lines. Inside the modulator, a solenoid-valve and electric pump connect to each of these hydraulic lines.The ABS brakes in actionIf your vehicle comes with ABS brakes, though, you won’t notice their existence until you need to step hard on your brake pedal during an emergency. Yet, the computer is constantly reading sensors' signals. Each sensor's tip has a small magnet. The teeth around each sensor rotor make the sensor's magnetic field fluctuate during wheel rotation, allowing the sensor to produce a small alternating current (AC) signal that travels down to the computer.However, this AC signal would suddenly decrease in frequency if you were to step hard on the brakes and one of the wheels on the systembegins to lock. At this point, the ABS computer would notice the sudden drop in the AC signal and realize the wheel is about to skid. The computer then orders the modulator unit to pulsate or pump hydraulic pressure on the locking wheel.This pumping action prevents the wheel from locking. Instead, it begins to rotate intermittently at a rate of about 15 to 20 times per second. Thus, the wheel maintains rotating friction on the road, prevents the car from spinning, and you still have steering control to avoid a hard collision if necessary.ABS technologykeeps improving. Thus, the particular configuration of the ABS brakes may change from one vehicle to another, depending on make and model. Yet, the job of the antilock brake system remains the same, prevent a wheel from locking and skidding during emergency situations. So, if your vehicle has ABS, rest assured you have that extra security.
