DRIVE-CONTROL COMPONENTS
-
ABS
<AWD>
3-47
ABS HYDRAULIC FUNCTION SCHEMATIC
The ABS in the AWD models is of two-channel sys-
tem (two-fluid pressure system).
In
this system, the
solenoid valves are energized or de-energized so
that the front and rear wheel brakes on the same
side are controlled on the “Select Low” rule.
For example, when either the front or rear wheel
on the right side is about to be locked, all the solenoid
valves on the right side, including those on the front
right wheel, are controlled to hold or slightly reduce
the fluid pressure. In order to prevent one wheel
locking state in the rear wheels, it is necessary
to control the rear wheels by Select Low as in the
FWD vehicles. In the case of the AWD vehicles,
the rear right and left wheels are subject to Select
Low control by the Select Low valves. As a result,
the fluid pressure for a total of three wheels (the
front right wheel and the rear right and left wheels)
are under simultaneous control.
Select-low: this is a method of providing the same
hydraulic control to both wheels when either wheel
is about to lock, matching it to the side about to
lock, or a method to control by matching pressure
to the low side.
-
Master cylinder
Wheel speed sensor (FR)
u
?ed
sensor (FL)
?ed
sensor (FL)
Wheel I
Hydraulic Unit (HU)
Hydraulic Unit (HU)
r------------r------------
Front left wheel
D
il
Front right wheel
Solenoid
valve control
Solenoid
valve control
b
c
Select Low
C
T
_)I
Reservoir J)
7
Select Low
I
I
n
Wheel speed
sensor (RR)
Rear right wheel
i
1
1
n
id
Rear left wheel
U-J
14A0629