High-tech batteries aren't just for early adopters driving Tesla's all-electric roadster. The fi rst cells for a hybrid will soon be fi tted in the classic Mercedes- Benz S-Class sedan. With a higher energy density, lithium-ion batteries provide the same wattage at a smaller
size than the nickel-metal-hydride packs in other hybrids. That allowed Mercedes to fit an electric motor in the new S400 BlueHybrid without reducing trunk space or legroom.
Power
A 20-horsepower electric motor gives the 3.5-liter V6 engine a boost during acceleration, approximating the performance of a V8
and helping the car achieve a combined fuel economy of 30 miles per gallon.
Packaging
The lithium-ion pack fits inside the S400's engine compartment, like a regular battery, instead of compromising cargo space, as in
the competing LS 600-h hybrid from Lexus.
Cooling
Mercedes engineers surrounded the battery with a gel that absorbs heat and cushions jolts. They also routed chilled air from the climate-control system around the power pack to keep it cool.
Start/Stop
The hybrid control module switches the engine off when the S400 slows to less than nine mph while coasting to a stop. When it's
time to take off, the electric motor silently restarts the gas engine.
Hybrids save fuel by shutting down the gas engine when they come to a stop. Now standard cars are doing the same. In 2007, BMW
introduced a system that combines a higher-capacity battery with a more-powerful starter motor that can crank the engine after every
stop. Mazda and Porsche recently announced 2010 models with stop-start functions. The Asian and European versions of the Mazda3
will actually stall the engine, then restart by injecting fuel directly into one combustion chamber and igniting it. Porsche hasn't
said how its four-door Panamera sedan will work, but it will probably use an electric starter motor like the BMW.
--
Sateesh.smart
No comments:
Post a Comment