What is the ABS anti-lock braking system in cars?
1 Answers
ABS, short for Antilock Brake System, functions by automatically controlling the braking force during vehicle deceleration to prevent wheel lock-up. It maintains the wheels in a state of rolling with slight slippage (slip ratio around 20%), ensuring maximum traction between the tires and the road surface. Classification of ABS: ABS is primarily categorized based on channels. In ABS systems, each brake circuit capable of independent pressure modulation is referred to as a control channel. ABS configurations include four-channel, three-channel, two-channel, and single-channel systems. Single-channel ABS: Also known as one-channel ABS, it features a single brake pressure modulator in the rear brake circuit and typically uses one wheel speed sensor mounted on the rear axle differential (though some models may have individual sensors per rear wheel). Two-channel ABS: This configuration struggles to balance directional stability, steering control, and braking efficiency, making it rarely used in modern applications. Three-channel ABS: Provides independent control for both front wheels while jointly controlling the rear wheels under the select-low principle (where both wheels are managed by one channel to prevent lock-up of the wheel with poorer traction), also called hybrid control. Four-channel ABS: Equipped with four wheel speed sensors, this system has individual brake pressure modulators for each wheel's brake caliper circuit, enabling fully independent four-wheel control.
