09 May 07
Coolant pumps: not sexy, but they can still make a difference
BMW has also turned its attention to some less obvious components, like the alternator, the tyres, the water pump, the power steering and even some flaps lurking behind the front grille. Not a sexy list.
The new electric coolant pump consumes less engine power, thus improving emissions and consumption. The latest electric power steering system is an on-demand system, so it's only on when it needs to be, giving a 90% energy saving compared to a conventional mechanical-hydraulic system. And the Efficient Dynamics air con system is disconnected from the drivetrain when not in use, again removing a potential drain.
Better injection, more efficiency
All but one of the latest 5-Series are fitted as standard with Brake Energy Regeneration. When the system spots that the engine is in over-run, such as when the driver is braking, it automatically engages the alternator to recharge the battery (a special high-capacity unit) with energy that would previously have been lost. It also reduces drag on the engine by only engaging and charging when required. (Don't be misled by the name - it doesn't directly involve the brakes at all.)
And most of the current 1-Series range comes with Auto Start-Stop, which saves fuel and reduces emissions. If the car is stopped and in neutral - when you're at a red traffic light, for instance - the engine will stop. Lights, wipers, the air con and the CD player will all continue to function as normal, so you'll barely notice that the engine has switched off. But then when you start to operate the clutch pedal the engine will fire up.
