0-5
TORQUE ON DEMAND
RODIUS 2007.07
3240-01
2. GENERAL DESCRIPTION
TOD system means the full time 4WD system and the registered trade mark of Borg Warner.
TOD is an abbreviation of Torque On Demand.
TOD (Torque On Demand) system, which is superior than existing Full Time 4WD, checks the
road surface and vehicle conditions via various sensors and, subsequently, according to the
situations and conditions, distributes the most optimal driving force to front wheels and rea
r
wheels by activating the electro-magnetic clutch located inside of TOD Transfer Case.
TOD receives the speed signals from speed sensors installed in front axle and rear axle, the
TPS signals from engine, and the operating signals from ABS control unit via CAN.
Based on these data, TOD control unit controls the electro-magnetic clutch to distribute the
3:97 ~ 44:56 of driving force to front wheels and rear wheels.
The conventional system uses “FR driving” (theoretically, the 100 % of driving force is
transferred to rear wheels) on normal paved road.
When the system detects a slip in the rear wheels, a proper percentage of driving force is
transferred to front wheels.
TOD control unit receives the wheel speed signals from the speed sensors in propeller shaft o
f
transfer case and engine output information from the engine control unit.
TOD control unit changes the pressure force of the electromagnetic clutch based on the
analyzed data.
1) Distribution of Driving Force According to Road Surface
On normal road surface ▶
In vehicle with existing part time transfer case, when a driver turns the steering wheel to park in
the 4WD mode, the vehicle may halt sensation of tight corner braking phenomena. However, in
vehicle with TOD system, this phenomena does not occur and the driving force is properly and
automatically distributed.
On paved road with high speed ▶
Driving at high speed on roads such as highway mainly uses rear wheels as driving wheel.
At this moment, some of torques is also distributed to front wheels so that the vehicle could
maintain safe ground grab capacity against side winds and rain.
Distribution ratio: 15 % for front wheels and 85% for rear wheels.
0-8
RODIUS 2007.07
4710-09
WHEEL
3. WHEEL ALIGNMENT
The first responsibility of engineering is to design safe steering and suspension systems. Each
component must be strong enough to with stand and absorb extreme punishment.
Both the steering system and the front and the rear suspension must function geometrically
with the body mass.
The steering and suspension systems require that the front wheels self-return and that the tire
rolling effort and the road friction be held to a negligible force in order to allow the customer to
direct the vehicle with the least effort and the most comfort.
A complete wheel alignment check should include measurements of the rear toe and camber.
1) Toe-in
2) Camber
Toe-in is the turning in of the tires, while toe-
out is the turning out of the tires from the
geometric centerline or thrust line. The toe
ensures parallel rolling of the wheels.
The toe serves to offset the small deflections
of the wheel support system which occu
r
when the vehicle is rolling forward.
The specified toe angle is the setting which
achieves-degrees “0°” of toe when the
vehicle is moving.
Incorrect toe-in or toe-out will cause tire
wear and reduced fuel economy. As the
individual steering and suspension
components wear from vehicle mileage,
additional toe will be needed to compensate
for the wear. Always correct the toe
dimension last.
Camber is the tilting of the top of the tire
from the vertical when viewed from the front
of the vehicle. When the tires tilt outward,
the camber is positive. When the tires tilt
inward, the camber is negative. The cambe
r
angle is measured in degrees from the
vertical. Camber influnces both directional
control and tire wear.
If the vehicle has too much positive camber,
the outside shoulder of the tire will wear. I
f
the vehicle has too much negative camber,
the inside shoulder of the tire will wear.
Camber is measured in degrees and is not
adjustable.
