What is a car brake and how does it feel?

Nowadays, there are more and more ABS (Anti-lock Brake System) in cars. Some manufacturers even use ABS to "talk about mountains and talk about water", as if ABS is superior to cars, and some simply stick ABS letters on their asses to show themselves. 1. What is a "brake lock"? Second, do cars have to have ABS? The original car is not bad without ABS. Why do you have to add ABS? Third, does ABS have a grade? What kind of abdominal muscles are best? Fourth, can ABS really shorten the braking distance?

In fact, ABS is a cliche, but because it is related to safety, it is better to know more. ABS is anti-lock braking in English.

The abbreviation of System (anti-lock braking system). Since ABS was introduced into cars from airplanes, it can be said that it is very popular, and many advanced cars have long listed it as standard. Now, equipped with ABS is no longer a patent for advanced cars.

First, when the tire loses ground friction because the brakes can't rotate, it can be said that the tire has been "locked" by the brake pads. If the front wheel is locked, at this time, any function of controlling and guiding the driving direction of the car is almost zero, so there is no corresponding relationship between the rotation of the steering wheel and the direction of the car, and the driving direction of the car cannot be controlled; If the rear wheel is locked before the front wheel, the ability of the rear wheel to control the rear of the car will disappear immediately. At this time, the force that prevents the wheel from moving forward will be concentrated on the front wheel, while the rear end will be distorted uncontrollably, which is often called "tail flick", which is quite dangerous at this time.

Second, when the vehicle brakes while driving, especially when braking suddenly, it is easy to cause the tires to lock and slip, and the body is easy to slip, and the head and tail are tossed. At this time, turning the steering wheel can't control the direction of the car, and the tire and the ground change from rolling friction to sliding friction, and the grip almost disappears. At this point, ABS will quickly "release" the brake friction plate when it senses that the tire is locked. This can relieve the tire from locking, maintain the adhesion between the tire and the ground, and facilitate the driver to control the direction of the car body.

In the absence of ABS, real drivers can still prevent the brakes from locking by "stepping on the brakes", but after all, these people are only a few. Moreover, if the grip of the four wheels is different, the high-grade ABS can adjust the braking force of each wheel according to the grip of each wheel, which is beyond the reach of any good driver.

Third, ABS certainly has grades. ABS is divided into electronic and mechanical types. Usually, the ABS equipped with the original car is electronic, and the ABS installed after the car purchase is mostly mechanical. Generally speaking, mechanical ABS is not as effective as electronic ABS.

Electronic ABS can be divided into three types according to the number of hydraulic circuits: one is single-circuit ABS. This kind of ABS only controls the rear wheels, most of which are installed on trucks, and only one wheel speed sensor is configured, which is usually installed in the rear axle differential. The most commonly used ABS for automobiles is a three-loop system, and the two front wheels are controlled by a set of oil circuits respectively. Because the center of gravity moves forward when braking, most of the braking force occurs in the front wheel and the load borne by the rear wheel is quite light, so only one set of oil circuit can control the two rear wheels. Each wheel of the four-loop ABS is responsible by an independent oil circuit, and the four-loop ABS is usually installed in high-performance cars.

Fourthly, ABS can shorten the braking distance, but the effect is still limited. ABS cannot greatly shorten the braking distance. On the normal straight, skilled drivers can often stop faster without ABS than with ABS. The main task of ABS is to avoid dangerous phenomena such as side slip and tail flick caused by tire locking. Therefore, when the brake disc is about to lock up due to excessive pressure, ABS will automatically sense and take appropriate intermittent braking pressure action. Before the tire locks (that is, before rolling), its friction with the ground can reach the maximum, which means that the deceleration force is the best and the braking distance is the shortest. So strictly speaking, shortening the braking distance is only an added value of ABS, so the effect is not obvious. The original intention of ABS is to prevent dangerous phenomena such as sideslip and tail flick.