The working principle and maintenance of ABS system

When braking, ABS can quickly judge the locking state of the wheels according to the speed signal transmitted by each wheel speed sensor, close the normally open input solenoid valve on the wheel that starts to lock, so that the braking force remains unchanged, and if the wheel continues to lock, open the normally closed output solenoid valve.

The braking pressure on this wheel is rapidly shifted down due to the presence of a line that runs through the brake fluid reservoir, preventing the wheel from being completely locked up due to excessive braking force. In keeping the braking state at the best point (slip rate S is 20%), the braking effect is the best and the driving is the safest.

The brake fluid in the front cavity of the brake master cylinder is the dynamic pressure brake fluid, which pushes the reaction sleeve to the right, which in turn pushes the booster piston to move the brake pedal push rod to the right. Therefore, when the ABS is at work, the driver can feel the pedal flutter and hear some noise.

After the car slows down, once the ABS computer detects that the wheel locking state is gone, it will let the main control valve close, so that the system can be transferred to the normal braking state to work.

If the pressure of the accumulator drops below the safe limit, the red brake fault indicator and the amber ABS fault indicator illuminate. In this case, the driver has to use a large force to apply a deep pedal-type braking method to effectively brake the front and rear wheels.

Nowadays, the vast majority of cars have long taken ABS (brake anti-lock braking system) as a standard configuration, but to say that they really understand the main functions of ABS, know what ABS can do, there are not many such people, so there are some misunderstandings about ABS.

Friends who have driven a car without ABS know that if you press the brake pedal to the end in an emergency, you can hear a squealing of tires, so two black tire marks are left on the road, which is left by the sliding friction with the road surface because the wheels cannot rotate (the technical term is called "wheel locking").

In fact, the wear and tear of the tires is still secondary, once the wheels are locked, the car is very easy to lose control, resulting in dangerous situations. If the front wheels are locked, the most direct thing is to lose the ability to steer, and hitting the steering wheel at this time will not help at all, but can only pray that the car will stop quickly!

If the rear wheels are locked, the steering ability is present, but there is a high probability that the rear wheels will slip sideways, and in severe cases, there will be a tail flick. Once the car skids or flicks, especially at high speeds, the body completely loses control and can only be resigned to fate!

Based on the fact that the wheel locking during braking will make the driver lose control of the car, so that the life safety of the driver and passengers is seriously threatened, how can the wheel lock during braking be effectively solved? This is where ABS (Anti-lock Braking System) was born.

As the name suggests, the anti-lock braking system means that the wheels do not lock when braking.

It is conceivable that when the driver quickly presses the brake pedal during emergency braking, the front wheels will not lock up, and the steering ability will still exist, so it is completely possible to take measures to avoid the danger ahead when braking. If the rear wheels don't lock up, there will be no side slip and tail flick, and control of the body remains in the driver's hands.

After the previous simple analysis, it can be concluded that in fact, the most important function of ABS is not to shorten the braking distance, but to be able to maintain the directional stability of the car when braking as much as possible.

When the anti-lock braking system is in effect, the friction between the wheels and the road surface is rolling friction, which will make full use of the maximum adhesion between the wheels and the road surface for braking, so as to improve braking deceleration and shorten the braking distance, but the most important thing is to ensure the directional stability of the car.

When ABS works, it is equivalent to a very high frequency of point brake, so in an emergency to press the brake pedal, you will definitely feel the brake pedal is shaking, and at the same time, you will hear the "click" sound from the brake master cylinder, which is ABS is working normally. Since the brake master cylinder is constantly adjusting the brake pressure, there is a continuous feedback force on the brake pedal. Therefore, in this case, it is necessary to "unwaveringly" press the brake pedal and at the same time take active measures to avoid danger.

ABS is an improved version of conventional braking technology. It works by relying on a highly sensitive wheel speed sensor mounted on each wheel and a speed sensor on the body and controlled by a computer. During emergency braking, once it is found that a certain wheel is locked, the computer immediately instructs the pressure regulator to release (depress) the brake cylinder of the wheel to make the wheel resume rotation.

The working process of ABS is actually the cyclic working process of locking-loosening-locking-release, so that the vehicle is always in a critical lock-up gap rolling state, effectively overcoming the deviation, side slip and tail flick during emergency braking, and preventing the occurrence of loss of control of the body.

1. When ABS braking, the high-speed retraction and release action of the brake cylinder will cause the high-pressure brake fluid to be squeezed frequently, resulting in loud sound, and the brake pedal will also have jitter and top foot phenomenon. Don't be bothered by this phenomenon when driving, use ABS braking in an emergency without hesitation, and press the brake directly to the end with force, and you can't relax.

Second, because the ABS emergency braking wheel is not locked, the front wheel still has a guiding role, the driver can brake while playing the direction for emergency avoidance.

3. The ABS system has very high requirements for brake fluid, so the addition of brake fluid should be strictly in accordance with the requirements of the instruction manual, and it is generally forbidden to dope different types of brake fluid. In general, the same type of brake fluid should be replaced once a year. Dot 3 or Dot 4 alcohol-based brake fluids are also available.

Fourth, ABS wheel sensor and ring gear are installed on each wheel, so always keep the sensor probe and ring gear clean, to prevent mud, oil, especially magnet substances from sticking to its surface, resulting in sensor failure or signal error to the computer and affect the normal operation of the ABS system.

5. Vehicles equipped with ABS system should strictly follow the specified tire pressure standards, and at the same time maintain the balance of coaxial tire pressure, and it is strictly forbidden to use tires of different specifications. In addition, it is necessary to pay attention to check the gap between the wheel speed sensor and the ring gear, and the excessive axial clearance of the wheel bearing directly affects the normal operation of ABS.

6. The driver should always pay attention to the ABS warning light on the dashboard while driving, if it is found that it flashes or does not go out, it means that the ABS system has been out of working state. At this time, the braking system has returned to the conventional braking interface, and the car can continue to drive, but it no longer has ABS function, and it is recommended to overhaul it as soon as possible.

How ABS works for electric vehicles.

How ABS (Anti-lock Braking System) works.

1. Principle: control device and ABS warning light, etc., in different ABS systems, the structure 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 ABS is usually composed of wheel speed sensor, brake pressure adjustment device, electronic is not the same.

In the common ABS system, a speed sensor is installed on each wheel, and the signal about the speed of each wheel is input into the electronic control device. The electronic control device monitors and judges the motion status of each wheel according to the signal input by the speed sensor of each wheel, and forms the corresponding control instructions. The brake pressure regulating device is mainly composed of a pressure regulating solenoid valve, an electric pump and a liquid reservoir to form an independent whole, which is connected with the brake master cylinder and each brake wheel cylinder through the brake pipeline.

The brake pressure adjustment device is controlled by the electronic control device to adjust the brake pressure of each brake wheel cylinder.

2. The working process of ABS can be divided into conventional braking, braking pressure maintenance, brake pressure reduction, brake pressure increase and other stages. In the conventional braking stage, ABS does not intervene in the brake pressure control, each inlet solenoid valve in the pressure regulating solenoid valve assembly is not energized and is in the open state, each outlet solenoid valve is not energized and is in the closed state, the electric pump is not energized to operate, the brake pipeline from the brake master cylinder to the brake wheel cylinder is in a state of communication, and the brake pipeline from each brake wheel cylinder to the liquid reservoir is in a closed state, and the braking pressure of each brake wheel cylinder will change with the output pressure of the brake master cylinder. The braking process at this point is exactly the same as that of a conventional braking system.

The working principle of passenger car ABS is:

1. ABS system.

It is an anti-lock braking system that imitates the tire brakes when an airplane lands.

The function of this device is that when the car brakes, it automatically adjusts the pressure in the brake tube according to the speed of the wheels, so that the wheels are always in a slip state of rolling while locking, especially for emergency braking.

It will brake intermittently, i.e. brake-release-brake, to avoid danger. Anti-lock braking device, with a frequency of 6 10 times per second for braking-release-braking pulse braking, with electronic intelligent control mode instead of manual mode, to prevent wheel locking, so that the wheels always get the maximum braking force, and keep the steering flexible.

Second, the working principle of the ABS system.

1. ABS system monitors the rotation speed of 4 wheels. When a wheel is close to locking, the system releases the brakes of that particular wheel, allowing the wheel to resume turning.

2. After the wheel is about to resume rotation, apply braking hydraulic pressure to the brake of this wheel.

3. If the wheel is about to lock up again, this system releases the brake of this particular wheel.

4. This system repeats the above process many times within 1s in order to give full play to the maximum potential of the brake and ensure the stability and normal operation of the vehicle.

How ABS (Anti-lock Braking System) works.

The principle of automobile ABS is to suppress the braking system of the car, so as to avoid the situation of tire locking when the car brakes sharply, and prevent the vehicle from losing control and causing safety accidents. When the ABS system is damaged, the car will have tires locked when braking, the brake pedal becomes hard, the brake is weak, or the brake can not be released, etc., then you should go to the repair shop or 4S shop to ask professionals for inspection and repair.

Precautions when braking the car:

1. Avoid sudden braking

On the one hand, sudden braking will accelerate the wear of brake pads, on the other hand, it will increase the load on the car's start, produce unnecessary fuel consumption, and reduce the service life of the engine. Moreover, when braking suddenly, it is also easy to cause rear-end collision with the rear car. In the case of an emergency, the braking method of point brake should be adopted, which can not only prevent the wheel from locking up and losing control, but also reserve reaction time for the rear car.

2. Develop the habit of parking and pulling the handbrake

When the car stops and turns off or waits for a red light, it is necessary to develop the habit of pulling the handbrake when stopping. Prevent the car from slipping, and also avoid the second jujube accident caused by the rear-end collision of the car after the ride.

3. Try not to brake for a long time:

When the car is in the process of long downhill, try to avoid braking for a long time to prevent the brake pad from failing due to high temperature.

The principle of automobile ABS is to restrain the braking system of the car, avoid the tire or Dan lock when the car brakes suddenly, and prevent the vehicle from losing control and causing safety accidents. The ABS system is damaged, the car will lock up when braking, the brake pedal will become hard, the brake will not work, or the brake will not be able to brake, etc. At this time, go to the repair shop or 4S shop and ask a professional to check the repair.

Precautions when braking the car:

1.Avoid sudden braking:

On the one hand, the sudden braking failure will accelerate the wear of the brake pads, and on the other hand, it will increase the load of the car starting, produce unnecessary fuel consumption, and reduce the service life of the engine. And it is easy to cause a rear-end collision when braking suddenly. In an emergency, point braking is required, which can not only prevent the wheels from locking out of control, but also reserve reaction time for the rear car.

2.Get into the habit of parking the handbrake:

When the car stops or waits for a red light, you should develop the habit of pulling the handbrake when you stop. Prevent the car from skidding and avoid rear-end collisions causing secondary disturbances.

3.Try not to brake for long periods of time :

When the car is going downhill for a long time, try to avoid braking for a long time, so as to avoid the brake pads from failing due to excessive temperature.

Millions of car purchase subsidies.

I don't know how this ABS system works, but I do know that this function is very useful and stabilizes the body system.

Pneumatic anti-lock braking system (referred to as pneumatic ABS) is similar to the braking force control principle of hydraulic anti-lock braking system, that is, the rotational speed of the wheel is detected by the wheel speed sensor, when the wheel appears to slide without hunger locking trend or phenomenon, ABS electronic control unit ECU according to the signal band chant that the wheel speed sensor transmits, real-time adjustment of the braking force of the corresponding wheel, to avoid the wheel slipping locking, and then improve the steering maneuverability and driving stability under the emergency braking condition of the vehicle, Ensure that the driver is able to perform effective emergency avoidance maneuvers and reduce the emergency braking distance in most road conditions.

Of course I don't know, because I didn't study auto mechanic, so I didn't know anything about it.

I don't know, it's a very complex system, these things are very complicated, if you want to figure it out, you still have to consult a professional.