Bosch DSC 3.X User Manual download pdf (Page 41)

E46 Dynamic Stability Control Systems

Oversteer

Oversteer occurs when the driver wishes to turn a corner and the tail of the vehicle slides

outward, leading the turn. This is caused by the rear tires loosing traction and not being

able to hold against the centrifugal force acting upon the vehicle.

The DSC III can identify the situation and initiate a corrective action based on engine torque

reduction followed by a controlled brake intervention sequence if needed.

Engine torque reduction is carried out by the DME from a request by the DSC via the CAN

bus. The DME sends the torque reduction confirmation back to the DSC.

OVERSTEER CORRECTION

1. VEHICLE APPROACES TURN AT HIGH RATE OF SPEED:

- Driver steers into turn and applies brakes to slow down.

2B. Driver tries to compensate by oversteering which

diminishes lateral locating force even further.

Simultaneously, rear of car starts to slide out.

WITH DSC III

WITHOUT

DSC III

3. VEHICLE COMES

OUT OF TURN

SUCCESFULLY

2C. DSC III determines an OVERSTEER condition.

Engine torque is reduced via CAN Bus signalling.

Outside rear wheel is momentarily regulated to

counteract severe yaw angle (also helps to reduce

drive torque further.)

2A. Lateral locating forces are

diminished on rear wheels

due to high speed and

centrifugal force of

vehicle in turn.

2D. The torque reduction and rear brake regulation

should stabilize the vehicle at this point. If not

the left front wheel has a high degree of lateral

locating force and is momentarily regulated.

This action deliberately causes the wheel to shed

a calculated degree of it's locating force. This

counteracts oversteer yaw at this wheel and also

aids in slowing the vehicle down to correct it.

1 2 ... 36 37 38 39 40 41 42 43 44 45 46 47

No comments

Bosch DSC 3.X User Manual Page 41