GF42.45-P-0001F Electronic Stability Program (ESP), Function

GF42.45-P-0001F Electronic Stability Program (ESP), Function
MODEL 463.243 /244 /246 /247 /249 /250 /254 ## as of 127357 as of 1.9.01 up to 31.5.12, 463.270 /271 up to 31.5.12, 463.309 /322 /323 /332 /333 ## as of 127357 as of 1.9.01 up to 31.5.12
- with CODE (BB3) Electronic Stability Program (ESP)
MODEL 463.248 ## as of 127357 as of 1.9.01 up to 31.5.12
- with CODE (BB3) Electronic Stability Program (ESP)
- except CODE (979) Special protection version





1 General
^ The "Electronic Stability Program (ESP)" functionality is integrated as a software module in the ESP and BAS control module (N47-5).
^ The electronic stability program (ESP)
- is an active safety system to improve the stability of the vehicle in all driving situations,
- overrides the
- antilock brake system (ABS),
- electronic traction system (ETS) and
- Brake Assist (BAS) control functions and complements these functions with the additional
- ESP stability control function, which is available in all driving situations during which the actual behavior of the vehicle deviates from the desired behavior.
2 Advantages
^ Improves moving-off and acceleration capabilities by increasing traction; especially on road surfaces with different levels of grip and when cornering.
^ Improves active dynamic safety, since only a wheel which is not spinning can provide optimum traction with no loss of lateral stability.
^ Automatically adapts the engine torque according to the traction status of the wheels.
^ Reduces the risk of skidding under all road conditions by automatically stabilizing the vehicle when braking, accelerating or coasting.
^ Significantly improves the directional stability of the vehicle when cornering, also up to the critical limits.
^ Shortens the stopping distance when cornering or on slippery roads.
3 Function in normal mode
^ In the normal operating mode when ESP intervention is not required, the ESP is in the "ready for operation" mode and does not intervene in the driving dynamics of the vehicle.
^ The system must be free of faults for the ESP to be in the "ready for operation" mode.
4 Function in control mode
^ The ESP is activated automatically if the prerequisites for activation of the ESP occur.
The ESP and BAS control module (N47-5) determines the control mode according to the traction status of the vehicle. A distinction is made between the following control modes:
4.1 ABS control mode
--> ABS braking torque control
Prevents individual wheels locking up by controlling the brake pressure at the brakes of the affected wheels.
4.2 ETS control mode
--> ETS braking torque control
Reduces slipping of individual wheels by controlling the brake pressure at the brakes of the affected wheels.
4.3 BAS control mode
--> BAS brake application
Automatic generation of brake force in emergency braking situations. The brake force is boosted to the maximum possible level.
4.4 ESP control mode
^ During ESP stability control, combined control of the braking torque and drive torque influence the longitudinal, transverse and yaw velocity of the vehicle in line with the driver's requirements and the surface of the road.
--> ESP braking torque control
Improves the directional stability and road adhesion by controlling the braking torque at the brakes of the individual wheels.
--> ASR drive torque control
The ASR is activated automatically if the drive torque is too large and one or more wheels begin to spin. The drive torque is then reduced by engine management intervention.
^ The ESP stability control therefore ensures, within the bounds of physical limits, that the vehicle does not deviate from the course specified by the driver.
^ Deviations from the desired course are caused by forces acting on a vehicle from outside, such as one-sided braking and acceleration forces or lateral forces, which attempt to rotate the vehicle about its center of gravity and therefore affect the self-steering behavior of the vehicle.
^ Deviations from the desired course can occur both when cornering and when driving straight ahead:
- Example when cornering:
The frictional connection between the front or rear wheels and the road surface can be changed so that the vehicle no longer follows the direction of travel specified by the steering angle and this causes the vehicle to yaw from the intended course.
In this case the vehicle pushes outwards either over the front wheels (understeered) or over the rear wheels (oversteered).
- Example when driving straight ahead:
Uneven road conditions apply different forces of friction to the wheels and the slip of the individual wheels is different. Without slip control and without any kind of steering correction the vehicle would fail to hold its course.
4.5 Control mode with ESP switched off
^ When the ESP is switched off
- the ASR drive torque control
- and the ESP braking torque control when the vehicle is accelerating and rolling are switched off.
^ When the driver brakes the ESP braking torque control remains available up to a vehicle speed of approx. 60 km/h.