Monday, August 4, 2014

Antilock braking system (ABS) and working principle

In the automotive braking, if the wheels from locking slip, lateral adhesion between the wheels and the road will completely disappear. If only the front wheel (steering wheel) brake to lock the rear wheels slip while still rolling, the car will lose steering ability. If only the rear brake to lock the front wheels slip while still rolling, even by small lateral disturbance force, the car will also have a slip (drift) phenomenon. These are easily cause a serious accident. Therefore, you do not want the car when braking wheel brake to lock slip Autel MaxiCheck Airbag ABS SRS Light Service Reset Tool, but hope to edge trim wheel brake slip state.
     By experiment that, car wheel slip rate at 15% to 20%, between the tire and the road surface friction coefficient has the largest. So in order to give full play to the ability of this potential adhesion between tire and road, currently on most vehicles are equipped with anti-lock braking system (AntilockBrakeSystem), referred to as ABS . our shop supply Autel MaxiCheck Airbag ABS SRS Light Service Reset Tool
     ABS composition and working principle
     Typically, ABS wheel speed sensor is the installation of the braking system on the basis of the ordinary, ABS electronic control unit, brake pressure regulating device and other components of the brake control circuit.
     During braking, ABS electronic control unit (ECU) 3 continuously obtained from the wheel speed sensor 1 and the signal 5, and processed, to analyze whether there is a wheel is about to lock the slide drag.
     If no trailer wheel slip is about to lock, the brake pressure regulating means 2 is not involved in the work, the brake master cylinder of the brake cylinders 7 and 9 in communication, the brake wheel cylinder pressure continues to increase, namely, ABS braking process the pressurized state.
     If the electronic control unit determines that the individual wheels (assumed to be a left front wheel) is about to drag the locking slide, namely a brake pressure regulating means which issues a command to close the left front brake master cylinder and the wheel brake cylinder passages and the front left system wheel cylinder pressure no longer increases, namely ABS braking process of packing state.
     If the electronic control unit determines that the locking of the left front wheel tends to drag the slider still state, namely it issues a command brake pressure regulating means, to open the left front wheel brake cylinder and the reservoir chamber or the accumulator (not shown) the channel, so that the left front wheel cylinder braking oil pressure decreases, namely, the pressure during ABS braking condition.
ABS hydraulic control assembly structure ,to buy Autel MaxiCheck Airbag ABS SRS Light Service Reset Tool visit our shop
     ABS hydraulic control assembly is in the hydraulic unit on the basis of ordinary braking system designed after the installation of ABS brake pressure regulator formed.
     Hydraulics ordinary braking system generally includes brake booster, brake master cylinder, double chamber, reservoir chamber, brake wheel cylinder and dual hydraulic lines and so on. In addition to the hydraulic braking system outside an ordinary member, ABS brake pressure regulator usually consists of an electric pump, the accumulator, the main control valve, the solenoid control valve and some control switches and other components. Essentially, ABS system is controlled by a hydraulic control valve solenoid on the valve body Cylinder quickly becomes larger or smaller, in order to achieve the anti-lock braking function.
     (1) electric pump
     The electric pump is a high pressure pump, which can be pressurized brake fluid in a short time (in the storage vessel) to 15 ~ 18MPa, and the entire hydraulic brake system provides a high pressure liquid. Electric pump can be started in the car to complete the work within one minute. Electric pump operates independently of the ABS computer, computer failure or wiring if there is a problem, the electric pump can still work.
     (2) the accumulator
     Diverse forms of energy storage structure. Autel MaxiCheck Airbag ABS SRS Light Service Reset Tool used more as a piston - spring-accumulator, the accumulator located between the solenoid valve and back to the pump, the wheel cylinder to the hydraulic fluid into the accumulator, thereby compressing the spring so that the hydraulic accumulator cavity volume change large to temporarily store the brake fluid.
     (3) solenoid control valve
     The electromagnetic control valve is an important component of the hydraulic actuator, it is done by the control of the ABS. ABS systems have one or two solenoid valve, which has a plurality of solenoid-controlled valve, the front and rear wheels, respectively, brake control. There are three commonly used three-way solenoid valves and two two-way valves and other forms.
     (4) pressure control, pressure and level warning indicator switch
     Pressure control switch (PCS) working independently of the ABS computer, monitoring the pressure of the lower chamber of the accumulator. Pressure Alarm Switch (PWS) and level indicator switch (FLI) function is, when the pressure drops to a certain value (14MPa or less) or when braking level drops to a certain extent, the fault indicator lights and ABS braking system fault indicator, while allowing the ABS anti-lock brake computer stops working.

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