4WD ECU processes
signals from various sensors and determines the current road and driving
conditions. The ECU then utilizes this information to implement precision
control over the 4WD coupling's multi-plate clutch and variably adjust the
amount of torque delivered tothe rear wheels.
Four Wheel Drive (4WD) transfer mode
selection
1. |
AUTO MODE:
A. |
When driving in 4WD AUTO mode, the
vehicle operates similar to conventional 2WD vehicles under
normal operating conditions. However, if the system determines
that there is a need for the 4WD mode, the engine’s driving
power is distributedto all four wheels automatically without
driver intervention. |
B. |
When driving on normal roads and
pavement, the vehicle moves similar to conventional 2WD
vehicles.
| |
2. |
LOCK MODE:
A. |
This mode is used for climbing or
descending sharp grades, off-road driving, driving on sandy
and muddy roads, etc., to maximize
traction. |
B. |
This mode automatically begins to
deactivate at speeds above 30 km/h (19 mph) and is shifted to
4WD AUTO mode at speed above 40 km/h (25 mph). If the vehicle
speed decelerates to below 30 km/h (19 mph), however, the
transfermode is shifted into 4WD LOCK mode again.
| |
Electronic Coupling - 4WD Control (By Driving
Condition)
1. |
Cruising (Auto Mode)
- Power is delivered mostly to the front
wheels.

|
2. |
Cornering (Auto Mode)
- Adjusts the amount of power to the rear
wheels based on the turning radius and cornering speed.

|
3. |
Wheel Slip (Auto Mode)
- If one or both of the front wheels lose
traction, the system transfers an appropriate amount of power to the
rear wheels based on the slip amount at the front
wheels.

|
4. |
Lock Mode
- Maximizes rough terrain performance (active
only at speeds below 40 km/h).

|
[Inactive]

[Active]

Operation Order
1. |
4WD ECU receives CAN signals from the
vehicle's sensors. |
2. |
4WD ECU calculates the necessary amount
of rear-wheel torque and sends the corresponding driving
current to the actuator (electronic motor and hydraulic
pump). |
3. |
Hydraulic pressure generated by the
actuator moves the piston. |
4. |
Friction from the piston's movement
engages the clutch. |
5. |
Power is delivered to the rear
wheels. | |