The braking performance of automobile is also one of the main performances of automobile. Since the birth of the car, the braking performance of the car is very important; And with the development of automobile technology and the improvement of automobile speed, its importance is becoming more and more obvious. Braking is directly related to traffic safety, and major traffic accidents are often related to long braking distance and side slip during emergency braking. Therefore, the braking performance of a car is an important guarantee for driving.
Automobile braking and its evaluation index
The ability of a car to stop in a short distance and keep the driving direction stable, the ability to keep a certain speed when going down a long slope, and the parking braking performance of a car that can stop for a long time on a certain slope are called the braking performance of a car.
The braking performance of automobile is mainly evaluated from three aspects: braking efficiency, constancy of braking efficiency and directional stability of automobile braking.
1. Brake control system for improving automobile safety
In traffic accidents involving automobiles, the safety fields such as accident prevention, accident avoidance and passenger protection are closely related to the sports performance of automobiles. The driver plays an important role in accident prevention, and the passive safety equipment of the automobile plays a role in protecting passengers at the moment of the accident. The avoidance of the accident is closely related to the brake control system of the automobile. People and environment play a major role in accident prevention, and vehicles play a major role in accident avoidance. In automobiles, besides ABS, TCS, ESP(VSC, VDS), there is also BAS (Brake Assist System) to improve safety.
During emergency braking, BAS will automatically sense and output stronger braking force according to the speed and intensity of stepping. Its working principle is to increase the vacuum in the brake pump, so that you can step on it, greatly improving the braking force, thus improving driving safety. Even if the car has turned off, it will maintain its braking ability for a period of time. Its function is to provide additional braking force to help drivers who fail to form a large braking force in time during emergency braking, and the braking force is helpful to speed up the movement of the brake pedal; When the braking force exerted by the driver on the brake pedal is not too large, increase the braking force to make the emergency braking performance of the vehicle reach the best. According to the survey, about 90% drivers are hesitant in emergency braking, and BAS can detect the driving situation of the vehicle from the speed at which the driver presses the brake pedal. In an emergency, when the driver does not press the brake pedal hard enough, BAS will start in less than 1 second and increase the braking force to the maximum, thus shortening the braking distance of emergency braking.
Although ABS can shorten the braking distance, if the driver uses point braking, the wheels will often not lock, and ABS will not have a chance to play a role. Brake-assisted BAS makes the existing ABS have some intelligence. When the driver presses the brake pedal hard and fast, BAS will judge that the vehicle is braking urgently, thus starting ABS and increasing the braking force quickly.
Second, the maintenance and correct use of ABS system
As an active safety device, ABS (Anti-lock Brake System) has been widely used in modern automobiles. Because its control mode and working process in the braking process are different from the previous ordinary braking system, it is also different from the traditional braking system in use and maintenance, otherwise it will lead to the failure of ABS system.
Summing up years of maintenance experience, the author thinks that car owners should achieve "four musts" and "four don 'ts" when using cars equipped with ABS system.
Four elements
(1) Always put your foot on the brake pedal. Only in this way can sufficient and continuous braking force be ensured and ABS can play its role effectively.
(2) Keep enough braking distance. When driving on good roads, at least 3s braking time should be guaranteed from the preceding vehicle; When driving on bad roads, you should set aside more time to brake.
(3) Practice using ABS in advance to prepare yourself for the vibration of the brake pedal when ABS works.
(4) Read the driver's manual in advance. In this way, we can learn more about various operations.
Four didn't.
(1) Don't drive a car with ABS more casually than a car without ABS. Some car owners think that the safety of the car will increase after ABS is installed, so their thoughts will relax during driving, laying a hidden danger for the accident.
(2) Don't step on the brake pedal repeatedly. When driving a car with ABS, repeatedly stepping on the brake pedal will make ABS work intermittently, reducing braking efficiency and increasing braking distance. In fact, ABS itself will automatically increase or decrease the braking force at a higher rate and provide effective direction control capability.
(3) Don't forget to control the steering wheel. When braking, ABS system provides the driver with reliable direction control ability, but it can't automatically complete the steering operation of the car. In the event of an accident, you need someone to complete the steering control.
(4) Don't be frightened by the normal hydraulic working noise of ABS and the vibration of brake pedal during braking. This kind of sound and vibration is normal, and the driver can feel the ABS working.