9.4.2. Distance control
Distance control is the core function of the ACC Stop & Go system and is integrated into Integrated Chassis Management. Two buttons on the multifunction steering wheel enable the driver to select a desired distance from one of four stages. The ACC Stop & Go system uses this preselection to calculate the set-point distance to be used in control.
| Index | Explanation |
|---|---|
| A | Set-point distance |
| B | Vehicle driving speed |
| 1 | Set-point distance, vehicle on the move, in proportion to driving speed |
| 2 | Set-point distance, vehicle at standstill, constant |
| 3 | Resulting set-point distance from the proportions |
The set-point distance with the car on the move is proportional to driving speed (1). At low driving speeds and at a standstill, the proportional distance to the driving speed is no longer used for ACC Stop & Go, but instead a fixed value in metres (2). Distance control uses the processed data for the object with the highest evaluator value as its input variables.
Distance control takes the following situations in particular into account:
- Maximum values for acceleration and deceleration:
- Congested-traffic stability:
The maximum values for acceleration and deceleration of the ACC Stop & Go system below approx. 50 km/h/31mph are dynamic values. They correspond to the acceleration values which the driver personally would use and sense as comfortable. Depending on the situation, ACC Stop & Go accelerates at a maximum of up to approximately 2 m/s2 and decelerates at maximum of up to approximately 4 m/s2 .
In very tight traffic and at very low driving speeds, there is an increased risk of collisions from sharp acceleration and braking. Therefore the ACC Stop & Go distance controller is designed to decelerate as early as possible, but not more than the vehicle ahead. In following mode, the system can decelerate at a maximum of up to 2.5 m/s2 , during a stopping procedure at a maximum of up to 4 m/s2 .