ELECTRONICALLY CONTROLLED 4WD
REAR AXLE
27-6
ELECTRONICALLY CONTROLLED 4WD
GENERAL INFORMATION
M2270000101136
• Electronically controlled 4WD has been adopted
to ensure the on-road performance, achieve
lighter and smaller body, and realize better fuel
economy.
• The electronically controlled 4WD controls the
torque of the electronic control coupling located
between the propeller shaft and rear differential.
This strategy is enabled by varying the torque
distribution to the front and rear wheels from the
status closer to the front wheel drive to the status
closer to the direct coupling 4WD and realizes the
optimal drive force according to the various driv-
ing conditions.
AIMS OF DEVELOPMENT
Lightweight and simple construction of the electroni-
cally controlled 4WD achieves good fuel efficiency
and provides enjoyment of selecting the drive mode.
FUNCTION
• The adoption of the electronic control coupling
prevents the tight corner braking phenomenon
*
and satisfies the traction performance.
NOTE:
*
Tight corner braking indicates the following
condition. When the 4WD vehicle turns sharply
on a pavement at low speed (ex. parallel park-
ing), the rotational radius of the front and rear
wheels differs, and this difference can no longer
be compensated by the tyre slippage. At this
time, the driver feels as if the brake was applied.
• The electronically controlled 4WD receives the
signals of the throttle position and vehicle speed
via CAN
*
communication protocol, detects the
vehicle driving condition and operation of the
driver, and distributes the proper torque to the
rear wheels.
NOTE:
*
: For more information about CAN (Control-
ler Area Network), refer to GROUP 54C
P.54C-2
.
• Under severe driving condition, the system is pro-
tected by minimizing the limitation force of the dif-
ferential.
• During high-speed driving, the fuel efficiency is
improved by reducing the limitation force of the
differential.
• The following drive modes are available accord-
ing to the drivers' preference to provide the enjoy-
ment of selecting functions.
Drive
mode
Control content
Appeal point
4WD
ECO
Minimizes the
limitation force of
the differential.
High fuel efficiency
mode. This mode is
ordinary driven on
efficient 2WD and
provides 4WD
performance on
wheel slipping
conditions.
4WD
AUTO
Increases the
limitation force of
the differential
according to the
different rotation
speed of the front
and rear wheels
and the throttle
position.
Normal mode. This
mode achieves
adequate 4WD
performance on
various conditions,
dried pavement, wet
road, snow road, etc.
4WD
LOCK
Further increases
the limitation force
of the differential
compared to the
4WD AUTO.
High traction mode.
This mode excels at
rough road driving
and escape from
stuck conditions, in
addition, realizes
strong 4WD driving
from low speed to
high speed on
ordinary road.
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