BMW 3: Stretch of road

The stretch of road is evaluated by means of the navigation system data.

Detected situations

• Top speed limitations
• Bends
• Traffic circles
• Off ramps/exits
• Turning-off priority roads
• Red lights*

* Only with the optional equipment Driving Assistant Professional (SA 5AU).

For US version vehicles: Only with the optional equipment Traffic Jam Assistant (SA 5AR).

If the system detects a traffic situation in which no braking operations are necessary, the vehicle coasts as soon as the driver takes his/her foot off the accelerator pedal. If the system detects a traffic situation in which braking operations are necessary, the vehicle is specifically decelerated to the prevailing or requested speed by recuperation.

G20 PHEV, adaptive recuperation

1. Free driving
2. Detected vehicle in front
3. Deceleration situation
4. Traffic light situation

1. Coasting
2. Adaptation of coasting recuperation to the respective situation

Example without adaptive recuperation

Initial situation: The driver drives towards a vehicle in front which is travelling at a lower speed.

G20 PHEV, recuperation strategy without adaptive energy recovery

1. Case A
2. Case B

1. Speed of own vehicle
2. Speed of vehicle travelling in front
3. Renewed, avoidable traction (double energy conversion)
4. Included nominal distance
5. Traction
6. Predefined recuperation
7. Brake actuation by the driver

Case A: If the driver takes his/her foot off the accelerator pedal too early, the predefined recuperation ensues in accordance with the driving mode and the current speed. The driver's own vehicle would decelerate too heavily, making it necessary for the driver to accelerate. This is inefficient and uncomfortable.

Case B: If the driver takes his/her foot off the accelerator pedal late, the predefined recuperation would not be enough to slow the driver's own vehicle down to the speed of the vehicle in front. The driver must actively engage with brake intervention. Depending on the deceleration, energy is recovered more heavily through regenerative braking and the kinetic energy is not completely lost. This is nevertheless uncomfortable for the driver.

Situation example with adaptive recuperation

Same initial situation: The driver drives towards a vehicle in front which is travelling at a lower speed.

G20 PHEV, recuperation strategy with adaptive recuperation

1. Case A
2. Case B

1. Speed of own vehicle
2. Speed of vehicle travelling in front
3. Included nominal distance
4. Traction
5. Coasting
6. Adaptive recuperation

Case A: If the driver takes his/her foot off the accelerator pedal too early, adaptive recuperation uses the still sufficient distance for coasting. Only as the distance decreases is the vehicle automatically decelerated by recuperation to the speed of the vehicle in front. The extent of energy recovery is adapted to suit the situation in the process. A speed-dependent nominal distance is included during the control operation.

Case B: If the driver takes his/her foot off the accelerator pedal late, adaptive recuperation prevents coasting and immediately starts with recuperation. Recuperation is increased compared with case A to achieve a sufficient deceleration.

Adaptive recuperation permanently evaluates the current driving situation. If the driving situation changes during the control operation, the changed situation is evaluated and the control operation resumed accordingly.

Example: The driver's own vehicle slows down to the speed of the vehicle in front, but the vehicle in front now changes lane. If the driver's own lane is free or a new vehicle in front is travelling faster than the driver's vehicle, the system switches to coasting. If the driver's own lane is occupied by a new, slower vehicle in front, the vehicle is in turn slowed to the slower vehicle's speed.

The same happens when traffic lights are just changing or traffic cuts into the driver's own lane.

On tight bends the radius is used to calculate a bend entry speed to which the vehicle can be specifically decelerated. In this way, for tighter bends a lower bend entry speed can be calculated and recuperation can be higher.

During recuperation to speed limits ahead the target speed is calculated with a tolerance value of approximately 6 mph (+10 km/h). The situation may thus arise where the vehicle arrives 6 mph (10 km/ h) faster at the requested speed limit.

If the vehicle has not yet reached the prescribed speed at the requested point, recuperation continues until the vehicle attains the requested speed.

Pressing the brake or accelerator pedal deactivates adaptive recuperation.

Adaptive recuperation facilitates energy-optimized and comfortable deceleration by coasting recuperation. There is no automatic braking for obstacles by the function. The driver is responsible for adhering to the speed and the requested minimum distance.

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