GF42.46-P-1000SL SBC Normal Braking, Function

GF42.46-P-1000SL SBC normal braking, function





Normal braking, pressure buildup
Each brake application begins when the driver presses the brake pedal.

The ESP, SPS [PML] and BAS control unit (N47-5) calculates the brake pressure. The specified data are passed on to the SBC control unit (A7/3n1) and this starts with the control in the SBC hydraulic unit (A7/3).

At the beginning of the brake application, the left and right front separation valves (A7/3y1, A7/3y2) are closed. They remain closed only during the control phase (except for during temperature compensation or activation via the brake pedal) and are otherwise open (de-energized).

The front left (A7/3y7), front right, (A7/3y9), rear left (A7/3y11) and rear right (A7/3y13) outlet control valves are likewise closed. The left front inlet control valve (A7/3y6), right front inlet control valve (A7/3y8), left rear inlet control valve (A7/3y10) and right rear inlet control valve (A7/3y12) are open.

The front axle balance valve (A7/3y3) and rear axle balance valve (A7/3 y4) remain open.

The pressure from the pressure reservoir (3) can now be built up at the brake calipers (5a, 5b) of the front axles via the left front (7) and right front dividing pistons (8). The pressure is increased directly at the rear axle.





Normal braking hold pressure
The control procedure described in the example and the corresponding valve positions relate to the complete brake system. They can, however, be used individually at each wheel.

Function
As soon as the computed brake pressure is reached, the left front inlet control valve (A7/3y6), right front inlet control valve (A7/3y8), left rear inlet control valve (A7/3y10) and right rear inlet control valve close (A7/3y12).

The left front outlet control valve (A7/3y7), right front outlet control valve (A7/3y9), left rear outlet control valve (A7/3y11) and right rear outlet control valve (A7/3y13) remain closed.

The front axle balance valve (A7/3y3) and rear axle balance valve (A7/3y4) remain open.





Normal braking, pressure reduction
The control procedure described in the example and the corresponding valve positions relate to the complete brake system. They can, however, be used individually at each wheel.

If the brake pressure required for braking is too high, the pressure reduction phase of the control mode begins.

Function
The left front outlet control valve (A7/3y7), right front outlet control valve (A7/3y9), left rear outlet control valve (A7/3y11) and right rear control valve (A7/3y13) are opened.

The left front inlet control valve (A7/3y6), right front inlet control valve (A7/3y8), left rear (A7/3y10) inlet control valve and right rear inlet control valve (A7/3y12) remain closed.

The front axle balance valve (A7/3y3) and rear axle balance valve (A7/3y4) remain open.

The brake fluid flowing back returns to the expansion reservoir via the return line (R).