2011 BMW 7 Series Owner's Manual - Page 29

Hybrid system At a glance Functions Boost Driving off and accelerating require a lot of en‐ ergy. To reduce fuel consumption during high acceleration and to optimize acceleration, the electric motor supports the combustion engine. For this purpose, the electric motor is supplied by the high-voltage battery. Energy recovery 1 2 3 4 Combustion engine Electric motor High-voltage cables: orange High-voltage battery The high-voltage battery of the hybrid system is charged through energy recovery. The electric motor acts as a generator and con‐ verts the motion of the vehicle into electric cur‐ rent. Charging can take place in various situations while the vehicle is being driven: ▷ When the vehicle is rolling if the accelerator is not pressed. ▷ During vehicle braking. When exerting gentle pressure on the brakes, the vehicle is only braked by the electric motor. When the brake pedal is depressed further, the brake system is activated additionally. This is why only part of the brake energy is used to charge the high-voltage battery when exerting firm pressure on the brake. Foresighted driving and the early reduction of speed are important to make full use of the hy‐ brid characteristics of your vehicle. The concept The hybrid system makes it possible to optimize fuel consumption and driving characteristics. An electric motor supports the combustion en‐ gine in certain driving situations. This lowers fuel consumption. In addition to this, the electric motor acts like an alternator: during braking, it converts the vehi‐ cle's kinetic energy into electricity. The current is stored in the high-voltage battery and is used to drive the electric motor. The hybrid system combines the following func‐ tions: ▷ Acceleration boost. ▷ Energy recovery: conversion and storage of kinetic energy as electric current. ▷ Automatic engine start-stop function: auto‐ matic stopping and starting the combustion engine when standing, for instance at a traf‐ fic light. ▷ Electric operation of the automatic climate control. Automatic Engine Start/Stop Function The automatic engine start-stop function, refer to page 67, switches the combustion engine off during a stop. Convenience functions such as the automatic climate control are supplied by the high-voltage battery and can remain switched on. The combustion engine starts again automatically for driving off. 29 Online Edition for Part no. 01 41 2 603 958 - 03 10 500 Reference Mobility Communication Entertainment Navigation Driving tips Controls At a glance BMW ActiveHybrid