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

DYNAMIC STABILITY CONTROL/ROLL STABILITY CONTROL

EBD CONTROL OPERATION

• 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.
Rear wheel slip ratio
Condition
0
1
2
After EBD control, slip
3
wheel slip ratio is δ% or
4
α—δ:Specified value

Operating Condition Transition Diagram

HIGH
SPEED
EBD INITIAL CONTROL VALUE
0
REAR SOLENOID
VALVE CONTROL
PRESSURE REDUCTION
PRESSURE MAINTAINED
PRESSURE INCREASE
HIGH
BRAKE FLUID
PRESSURE
0
End Of Sie
EBD control
determination
No slip No control
α%—β%
β% or more
ratio is γ%
more
ABS INITIAL CONTROL VALUE
0 1
EBD CONTROL AREA
Solenoid valve
Pressure increase
Control Pressure maintained
Pressure reduction/
Control
maintained
Pressure increase/
Control
maintained
Pressure reduction/
Control
maintained/ increase
VEHICLE SPEED
2 3
id041800818800
Comment
—
—
—
—
ABS control operates
REAR WHEEL
SPEED
FRONT WHEEL
SPEED
TIME
FRONT BRAKE
FLUID PRESSURE
REAR BRAKE
FLUID PRESSURE
4 TIME
ABS CONTROL AREA
ac9uun00000391
04-18–21
04-18