Mazda CX-9 2007 - Ebd Control Operation; Operating Condition Transition Diagram

DYNAMIC STABILITY CONTROL/ROLL STABILITY CONTROL
04-18–21
04-18
EBD CONTROL OPERATION
id041800818800
• Electronic brakeforce distribution (EBD) control detects the slip ratio between the front and rear wheels from
the antilock brake system (ABS) wheel-speed sensor signals. If the slip ratio of the rear wheels as compared to
the front wheels is larger than the fixed limit, the dynamic stability control (DSC)/roll stability control (RSC)
hydraulic unit (HU)/control module (CM) reduces brake pressure being distributed to the rear wheels. Due to
this, brake pressure distribution is constantly controlled in the proper proportion and in relation to vehicle load,
road surface conditions and vehicle speed.
• Determination of the rear wheel slip ratio, based on a comparison of the lowest front wheel speed and the
estimated vehicle speed with the rear wheel speeds, is divided into conditions 0—4 shown in the table below.
• The DSC/RSC HU outlet and inlet solenoid valves are operated and the brake fluid pressure controlled
according to these conditions.
• If ABS control conditions are met during EBD control, EBD control is stopped and ABS control is given priority.
α—δ:Specified value
Operating Condition Transition Diagram
End Of Sie
Condition
Rear wheel slip ratio
determination
EBD control Solenoid valve Comment
0 No slip No control Pressure increase —
1 α%—β% Control Pressure maintained —
2 β% or more Control
Pressure reduction/
maintained
—
3
After EBD control, slip
ratio is γ%
Control
Pressure increase/
maintained
—
4
wheel slip ratio is δ% or
more
Control
Pressure reduction/
maintained/ increase
ABS control operates
43210
0
0
REAR SOLENOID
VALVE CONTROL
PRESSURE REDUCTION
PRESSURE MAINTAINED
PRESSURE INCREASE
HIGH
BRAKE FLUID
PRESSURE
EBD CONTROL AREA
ABS CONTROL AREA
FRONT BRAKE
FLUID PRESSURE
REAR BRAKE
FLUID PRESSURE
TIME
HIGH
SPEED
EBD INITIAL CONTROL VALUE
ABS INITIAL CONTROL VALUE
VEHICLE SPEED
REAR WHEEL
SPEED
FRONT WHEEL
SPEED
TIME
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