Appeal Number: 2006-3054
Application Number: 10/672,625
calculates the appropriate brake pressure in view of the driver demand and the
wheel speed sensor 26 (col. 6, lines 33 to 35). ABS logic 40 in central control unit
10 contains rules for controlling the pressure in the brakes when a skid is detected.
When the wheels skid, ABS logic 40 responds by reducing the demanded pressure
Pa (pressure dump) transmitted to the local control 16 (col. 6, lines 11 to 19).
Therefore, the rule of the ABS logic for operation of the brakes is: when a skid is
detected, generate a signal for a pressure dump. However, the application of this
ABS logic 40 is delayed by delays 44a and 44b which would result in the brake
pressure response to the wheel skid being late. Therefore, Phoenix discloses:
Simple skid detection logic 46 within the valve controller
16 monitors the wheel speed S’ and can generate a
pressure dump signal Pd which will override for a limited
period the brake pressure demand Pa communicated from
the master controller 10 to a brake pressure control
element 48 which supplies the pressure control signals Pc
for the brake actuator 22 (not shown in Fig. 3) [col. 6,
lines 53 to 59].
The rules for controlling the pressure in the brakes when a skid is detected
for both the central controller 10 and the distributed controller 16 is to generate a
signal for a pressure dump. As such, both the central controller 10 and the
distributed controller 16 have the same control scheme in the event of a wheel skid.
However, when a skid is detected the distributed controller 16 is capable of
overriding the signal Pa coming from the central controller by its own signal Pd to
compensate for delay as discussed above.
The system of Phoenix includes a brake pedal, release of pressure on which
overrides the central control signal and the local control signal.
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Last modified: September 9, 2013