Monitor Object Ahead
The ACC systems views any vehicle traveling in the same lane as the subject vehicle, as an object. The operating limits of the system are as follows:
- Object Detection
The range of the ACC sensor is limited (approx. 120 meters).
- Vehicle Deceleration
The LDM is only able to effect limited deceleration (max. 2.5 m/s2 ) via the Dynamic Stability Control (DSC). This means that the LDM is only able to compensate for a limited relative speed.
If the limit of the functional range is reached, the driver is requested to act, as follows: Display for the monitored vehicle flashes red and an acoustic signal sounds.
- Lateral Monitoring Range
The lateral monitoring range of the ACC sensor is limited, meaning that a monitored vehicle ahead could be lost due to a tight bend.
In such cases, cruise control will not accelerate to the set speed for approx. 2 seconds. This will prevent the vehicle from accelerating too close to the vehicle ahead, which may only momentarily not be monitored.
When driving straight ahead, this can cause a delayed reaction to another vehicle which may closely cut in front of the subject vehicle. The vehicle cutting in will not be monitored by the ACC system until it is clearly in the same lane as the subject vehicle.
- Lateral Acceleration
The LDM limits the lateral acceleration up to approx. 4.0 m/s2 in favor of driving comfort. The LDM is unable to work in an anticipatory manner when the vehicle is cornering. It is only able to react to existing lateral acceleration when it is already on the bend. For this reason, the driver is responsible for ensuring that an appropriate speed is being driven as the vehicle enters the bend.
The radar waves received cannot distinguish between animals, vehicles and traffic signs. Traffic signs and parked vehicles standing next to the vehicle's lane could incorrectly be assigned to the lane. In order to prevent incorrect reactions, stationary objects and traffic in the other direction is ignored in the distance control.
Vehicles that are operating/traveling in other lanes are of generally of no interest for the ACC system.
If an object is in the monitoring range, the reflected radar waves are received depending on the angle between the wheel axis and the object.
4 antennas receive different amplitudes, depending on the amplitude of the signal received the system will react accordingly.
The ACC uses the turn signal indicator signal from the Footwell Module (FRM) for quicker recognition when changing lanes. In other words, if the turn signal indicator is activated prior to overtaking/passing, the vehicle being overtaken is ignored more quickly. On the other hand, in the event of a change to the previous lane, a vehicle driving there is monitored more quickly.