Operation - Mazda CX-9 2007 Service Highlights

DYNAMIC STABILITY CONTROL/ROLL STABILITY CONTROL

Operation

Front and rear (AWD)
• As the ABS sensor rotor rotates, magnetic flux
formed from the permanent magnet varies and
alternating current is formed with an
electromagnetic conductor. Using this alternating
current, rotation speed is expressed as a varying
proportional cycle and from detection of this cycle
the control module (CM) part of the dynamic
stability control (DSC)/roll stability control (RSC)
hydraulic unit (HU)/CM can then detect the wheel
rotation speed. While the structures of the front
and rear ABS wheel-speed sensor differ, the
operation is the same.
Rear (2WD)
• As the rear ABS sensor rotor rotates, the magnetic flux between the rear ABS wheel-speed sensor and the rear
ABS sensor rotor change periodically. This periodic change is in proportion to the rotation speed.
• The semiconductor element in the wheel speed sensor detects the change in magnetic flux, and the active
drive circuit converts it to a rectangular wave signal for the current, which is transmitted to the DSC/RSC HU/
CM.
• For every single rotation of the ABS sensor rotor, 44 rectangular wave pulse signals are output. The CM in the
DSC/RSC HU/CM calculates the wheel speed from the periodicity of these pulses.
DETECTION PRINCIPLE
ABS WHEEL-SPEED SENSOR
SEMICONDUCTOR
ELEMENT
ABS SENSOR ROTOR
End Of Sie
NG: COMBINED SENSOR
04-18–28
ACTIVE DRIVE CIRCUIT
MAGNETIC RUBBER
(MAGNETIC ENCODER)
OUTPUT VOLTAGE WAVEFORM
V
AT LOW SPEED
OUTPUT WAVE PATTERN
ACTIVE DRIVE CIRCUIT
HI
RECTANGULAR
WAVE SIGNAL
LO
SEMICONDUCTOR
ELEMENT
AT HIGH SPEED
ac9uun00000398
ac9uun00000399