Understand the ABS system
Brake performance is one of the main functions of a car, which is related to driving safety (a bit nonsense, but how many people have really paid attention to this when buying a car, especially They are some small-displacement cars). The most basic indicators to evaluate the braking performance of a car are braking acceleration, braking distance, braking time and directional stability during braking.
ABS (Ant-ilock Brake System) History:
The design idea of ??the braking force adjustment device was proposed in the late 1920s, when someone obtained a patent in this area (specifically No one knows). In the 1950s, the world's first anti-lock braking system, ABS, came out in 1950 and was first used on aircraft in the aviation field. Knorr Company (located in Munich, this company is the world's largest company famous for the production of braking systems) company's anti-lock brakes (ABS) began to be used on trains. The purely mechanical test receiving and recording devices at that time could not meet the higher requirements of automotive technology, so the effect of automotive ABS at that time was not very good. After a lot of experimental research, it was finally concluded:
“The sensor for testing the wheel rotation and the controller for adjusting the rotation are indispensable to achieve the goal”
This is the car Important theoretical basis for the development of ABS systems!
In the 1970s, Mercedes-Benz began to envision and announced in the press that it would use electronically controlled ABS in cars, trucks and buses, but there was no mature, mass-produced product yet. In 1978, Mercedes-Benz installed ABS on its S-Class luxury sedan for the first time. In 1984, ABS began to be equipped in batches on S-class, SL-class sedans and 190E gasoline-injection cars. From October 1992 to the present, ABS has become the basic equipment of all types of cars in Germany.
At present, the latest ABS has developed to the fifth generation. Today's ABS also has many functions, such as:
1. Electronic Traction System (ETS).
2. Drive anti-skid adjustment device (ASR)
3. Electronic stability program (ESP)
4. Auxiliary brake
More Classification of ABS:
Classified by mechanical and electronic, the two have the following differences
1. Electronic ABS is designed according to different models, and its installation requires professional If you switch to another vehicle, you must change its circuit design and battery capacity, which is not universal. Mechanical ABS is highly versatile and can be used on any vehicle with a hydraulic brake device. It can be used from one vehicle to another. Transfer it to another vehicle and installation only takes 30 minutes.
2. Electronic ABS is large in size, and the finished vehicle may not have enough space to install electronic ABS. In contrast, mechanical ABS is smaller in size and takes up less space.
3. Electronic ABS starts working when the wheels are locked, and works 6 to 12 times per second; mechanical ABS starts working when the brakes are applied, and works every second depending on the vehicle speed. Can be used 60-120 times.
4. The cost of electronic ABS is higher. In comparison, using mechanical ABS is more economical and practical.
According to the control channel classification, there are the following types:
Four-channel type, features: high adhesion coefficient utilization, and the maximum adhesion of each wheel can be utilized to the greatest extent during braking. Focus. However, if the adhesion coefficients of the left and right wheels of the car are greatly different (such as water or ice on the road surface), it will affect the stability of the car's braking direction. Guangzhou Honda uses a four-channel ABS device.
Three-channel type, features: The car has good directional stability when braking under various conditions. Three-channel ABS is commonly used in cars.
Two-channel type, features: It is difficult for two-channel ABS to take into account all aspects of directional stability, steering control and braking performance, and is currently rarely used.
One-channel type, Features: simple structure, low cost, etc., widely used in light trucks.
The basic components of the anti-lock braking system:
ABS usually consists of wheel speed sensors, brake pressure regulators, electronic control devices and ABS warning lights. In the ABS system, the structural form and working principle of the brake pressure regulating device are often different, and the internal structure and control logic of the electronic control device may also be different.
Various ABSs are the same in the following aspects:
(1) ABS only works after the car’s speed exceeds a certain level (such as 5km/h or 8km/h). Anti-lock brake pressure will be adjusted for wheels that tend to lock during braking.
(2) During the braking process, only when the controlled wheel tends to lock, ABS will perform anti-lock adjustment on the braking pressure of the wheel that tends to lock; when the controlled wheel When it is not locked, the braking process is exactly the same as that of a conventional braking system
(3) ABS has a self-diagnostic function that can monitor the working conditions of the system. When there is a fault that affects the normal operation of the system, the ABS will be automatically turned off and the ABS warning light will be illuminated to send a warning signal to the driver. The car's braking system can still brake like a conventional braking system.
ABS usage characteristics:
1. When braking on a road with low adhesion coefficient, the brake pedal should be pressed with one foot
2. It can Stop within the shortest braking distance
3. The car has high directional stability when braking
Finally, again, no matter how good the safety equipment is, it cannot compare Drive carefully and have superb driving skills! So don’t be too superstitious about these equipment. It’s better to be careful when driving!
The applicable characteristics of mechanical ABS need to be set in advance. On hydrophobic roads, ice and snow roads, gravel roads, and asphalt roads, the friction coefficients of tires are different; different vehicle speeds require different braking forces. . There is no real-time measurement feedback system and it only relies on preset threshold values. The applicable range is narrow and the braking effect may be reduced. The price of imported mechanical ABS is around 2,000 yuan, while the domestic one only costs more than 200 yuan.
To install electronic ABS, you need to replace four bearing seats, the left and right half shafts of the front wheels, the rear axle hub, wiring harness, sensors, ABS hydraulic pump, ABS indicator light, computer, brake oil pipe and brake fluid . If the installation position has been reserved on the body, there will be no problem with subsequent installation; if there is no installation position reserved, the strength of the installation part must be checked. The price is about 13,000 to 18,000 yuan