| TUCSON(LM) >2011 > G 2.0 DOHC > 4 Wheel Drive (4WD) System > 4WD Control System > 4WD ECU>Description and Operation |

Description
Four Wheel Drive (4WD) transfer mode selection
1. | AUTO MODE:
- | 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.
- | When driving on normal roads and pavement, the vehicle moves similar to conventional 2WD vehicles.
2. | LOCK MODE:
- | This mode is used for climbing or descending sharp grades, off-road driving, driving on sandy and muddy roads, etc., to maximize traction.
- | 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.
Operation
• | Normal driving situation: 2WD base driving
• | 4WD driving in driving situations (rapid activation, cornering etc.)
1. | Input the information from each sensor in vehicle
A. | Input torque (Throttle position sensor)
B. | Cornering situation (Steering angle sensor)
C. | Vehicle speed and different wheel speed front &rear (Wheel speed sensor)
D. | Braking situation (Brake signal and ABS signal)
2. | Distributed the required driving force after 4WD ECU operates.
3. | EMC (Electric Magnetic Clutch) operates the primary clutch.
4. | Control the cam's opening gap by operation of primary clutch.
5. | Control the slip of inner & outer plate. Control variably the driving force distribution to optimize front & rear driving force.