Are both ABS air brakes and oil brakes the same structure?

Nowadays, ABS has become the standard configuration of trucks, but before that, many micro trucks and light trucks were not even equipped with ABS anti-lock braking system. Dangerous situations such as loss of control of the front wheel direction and rear wheel flicking, especially on rainy and snowy roads, pose great safety hazards.

However, in GB12676-2014 and GB7258-2017 "Technical Conditions for Motor Vehicle Operation Safety", all N2 and N1 vehicles are required to be equipped with ABS anti-lock braking devices. According to the braking form, it is generally divided into air brakes and hydraulic brakes, and ABS is also divided into pneumatic ABS and hydraulic ABS. So what is the difference between them? How does it work? What should we pay attention to in daily use?

What are the advantages of ABS braking principle?

Whether it is pneumatic ABS or hydraulic ABS, their working principle is actually the same. They are all based on the conventional braking system, adding an electronic control system, which is mainly composed of sensors, brake pressure regulators, ABS warning lights, ABS electric Control unit (ECU) and other devices.

When the driver brakes in an emergency or on a slippery road, the ABS system can accurately detect the slippage of the front and rear wheels, complete the analysis, calculation and control through the ABS electronic control unit (ECU), and adjust the brake wheels in due course The brake pressure of the cylinder (brake air chamber) improves the longitudinal and lateral adhesion during braking and prevents the wheels from locking, thereby obtaining better directional stability, steering control and shortening the braking distance.

During normal braking, although ABS does not intervene, the entire system is monitoring the signal of the wheel speed sensor at any time to determine whether to activate the anti-lock braking state. When any wheel of the vehicle is close to being locked, the brake pressure regulator will adjust the brake fluid (hydraulic brake ABS) of the wheel brake cylinder or the brake pressure of the brake air chamber (air brake) according to the ECU instruction. ABS), to achieve the best pressure to maintain the state, to achieve the purpose of anti-lock.

What is the difference between hydraulic ABS and pneumatic ABS?

After talking about the common points, let's take a look at their differences. The biggest difference between hydraulic ABS and pneumatic ABS is the difference in the braking medium. The hydraulic ABS uses brake fluid, and an oil pump is installed in the system to control the circulation of the brake fluid to prevent the loss of brake fluid.

The working medium of air pressure ABS is air, and the air is basically a continuous flow. There is no need to set up a separate circulation system. The compressed air is generally released directly after work. We often hear the sound of the air brake, which is the sound after the system releases the air. .

Therefore, in terms of structure, air brake ABS will not only be simpler than liquid brake ABS, but also have a lower failure rate. Another difference is that hydraulic ABS usually only has one brake pressure regulator, while pneumatic ABS requires multiple brake pressure regulators, usually on the front and rear wheels.

ABS and the conventional braking system are a big whole, and the two cannot be separated. Once there is a problem with the conventional system, the ABS system will not work properly. Therefore, when overhauling, these two systems need to be overhauled together. When the brake system fails, in addition to checking the sensor, electronic controller and brake pressure regulator, it is also necessary to determine whether the failure is the conventional brake system or the ABS system. Many card users tend to separate the two for maintenance. This is not desirable.

Emergency braking experience is more important

When braking in an emergency, the most frequently asked question about ABS is whether to step on it with one foot or to brake with two feet. In fact, it should be divided into the loading situation of the goods, the road conditions and the weight of the whole vehicle. In particular, the trailer needs to adjust the braking force in real time according to the situation on the spot. There is no standard answer here. In the case of excessive braking or poor matching of the main trailer, it is extremely easy to push the head or roll when turning.

In the process of chatting with many car friends in the past, some car friends thought that the braking distance would be longer after ABS intervention. In principle, after the tire is locked, it will form sliding friction with the road surface, resulting in lower braking force and longer sliding distance. After the ABS system enters, it will adjust the braking force at high frequency so that the wheels are in a state between locked and rolling, and the brake disc is leading the braking, which can minimize the braking distance.

In many cases in the past, many tractors directly removed the drum brakes including ABS, wheel speed sensors and other devices in order to avoid the situation of the vehicle pushing the head. Such an approach is purely a joke in today's view. Nowadays, after the main suspension matching is adjusted, there will not be too much problem with the brake clearance. Of course, even if there is a problem, it should be adjusted through a professional service station instead of removing the front brake. , increasing safety hazards in vain.

In fact, hydraulic ABS and pneumatic ABS correspond to two types of braking: hydraulic brake and air brake. No matter what kind of ABS, we must master the correct operation method. Moreover, ABS has become a mandatory requirement of regulations. A set of high-quality ABS can not only improve braking performance and driving safety, but also avoid abnormal tire wear.

                                                                                                                                                                                                                                                                       来源：卡车之家，龚弋新