necessary for the system to start the combustion engine even when the vehicle is not moving. With prolonged driving in traffic jams, the combustion engine will be switched on and off to charge the high-voltage battery for the following start-stop phase.
Sailing
If the accelerator is not depressed and the lever is in Drive (D), the internal combustion engine is switched off even at higher speeds. The vehicle then decelerates slower than conventional vehicles.
This feature can be used to help reduce fuel consumption when you keep traffic conditions in mind and can anticipate the vehicles power requirements. Even in this case, the rev counter in the instrument cluster displays zero engine speed (0 engine revolutions). The instrument cluster powermeter shows zero.
Brake energy regeneration (Recuperation/charge)
When the vehicle brakes, the electrical energy is generated by the electric motor, which works as an alternator and charges the high-voltage battery. The same thing occurs while the vehicle is coasting to a stop or driving downhill.
Energy regeneration is shown in the instrument cluster display or on the Infotainment System screen. The combustion engine may be switched off automatically in this situation. The instrument cluster tachometer will show zero engine speed (zero engine revolutions). The instrument cluster powermeter shows zero.
Automatic starting - combustion engine
The combustion engine is started automatically in a number of situations.
x Engine temperature is too low.
x Catalytic converter temperature is too low.
x High-voltage battery being charged at high rate when decelerating. The high-voltage battery cannot absorb any more energy and for this reason the electric motor cannot brake the vehicle. The combustion engine comes on to help slow the vehicle down (engine brake).
x Engine hood is open.
x Leaving the vehicle when the electric motor is still “live”. The status of the electric motor is not always obvious, particularly when the combustion engine is not running. The combustion engine will therefore start if the driver's safety belt is unlatched or the driver's door is opened when the
transmission is in Park (P) or Neutral (N) ⇒ Warning when leaving the vehicle.
Energy flow display
Fig. 261 Energy flow display (Variant 1). Left: Instrument cluster. Right: Infotainment System.