ABS HU PART CONSTRUCTION/OPERATION

id041300185400


Construction

•  The integrated ABS HU/CM system controls the ABS. The ABS are an independent front wheel control, rear axle control, 4‐sensor, 3‐channel system.

Function of main component Parts

Part name

Function
Inlet solenoid valve, outlet solenoid valve
•  The solenoid valves control the fluid pressure at individual brake calipers (wheel cylinders) in accordance with the signal received from the ABS CM.
•  There are six solenoid valves in total and two solenoid valves in each wheel (one for retaining pressure and one for reducing pressure) are used. There are four valves for the front wheel, and the left and right wheels are controlled separately. There are two valves used to control the rear wheels simultaneously.
Reservoir
•  The reservoirs temporarily store the hydraulic pressure which flows from the brake caliper (wheel cylinder) through the outlet solenoid valve during pressure reduction.
Pump
•  The pump returns brake fluid from the reservoir to the master cylinder.
Pump motor
•  Operates the pump according to ABS CM signals.


Hydraulic circuit diagram

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Operating

•  The ABS HU/CM detects wheel-speed and driving condition based on the ABS wheel-speed sensors, and outputs on/off electronic signals to the inlet solenoid valves and outlet solenoid valves to control the ABS control.
•  The ABS HU/CM controls ABS by calculating wheel slip from ABS wheel‐speed sensor signals, and adjusting the brake pressure.

 

Solenoid valve (Inlet)

Solenoid valve (Outlet)

Pump motor, pump
Normal brake
Off (open)
Off (close)
Stopped
Pressure reduction
On (close)
On (open)
Operating
Pressure retention
On (close)
Off (close)
Stopped
Pressure increase
Off (open)
Off (close)
Stopped

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