February 12, 2009

HUMBUG PEAK:

Test-Driving VW's Touareg Hybrid: It's a little late to the party, but Volkswagen now realizes that if it wants to increase its U.S. market share, it needs hybrids, too (Jack Ewing, 2/12/09, Business Week)

Unlike the S-Class, which uses its electric motor only to assist the gasoline engine, the Toureg is a full hybrid that can run solely on electric power at low speeds, though only for a mile and a half or so. The Touareg's electric motor also provides an acceleration boost when needed, for example to pass a truck on the highway.

In fact, the hybrid Touareg will accelerate more quickly than any of the existing versions. VW says the prototype can go from zero to 60 mph in 6.8 seconds—though you certainly won't get maximum fuel mileage driving that way. The hybrid Touareg can also pull as much trailer weight as the gas versions. "We wanted this Touareg to drive just as well as any other Touareg," says Eike Feldhusen, one of the Volkswagen engineers who led the development of the hybrid. However, people who really use the car off-road a lot will probably want to stick with a traditional power train, which offers better power at low speeds.

The Touareg saves fuel in several different ways. The electric motor relieves the gasoline engine at low speeds, which is a particular advantage in city driving. In addition, the gasoline motor automatically shuts down when the car is coasting or stopped, restarting when you press the gas pedal. And the car recaptures energy normally lost from braking, with a mechanism that transfers the kinetic energy to the generator instead of the brake pads.

As I drove the Touareg on roads in and around Wolfsburg, it occurred to me that another one of the ways hybrids save fuel is by providing positive feedback to the driver. When you set off in the Touareg, a display right in front of the steering wheel tells you your average fuel economy. A second display, featuring a graphic of the power train, glows green when you're using braking energy to recharge the battery, blue when you're running on electric power alone, and ochre when you're drawing on the gasoline motor, a 3.0-liter V6 adapted from the Audi S4.

After a while it gets to be a game. Just how much fuel economy can you eke out? How long can you run on electric power alone and get the display to glow green? (Normally the gas engine kicks in at about 10 mph, but VW engineers say they've gotten the car up to almost 50 mph on electric power alone, albeit on a very flat road.)

You become acutely aware of how your style of driving affects fuel economy. With the Touareg, slow acceleration gets the most out of the electric motor, while slow braking is the best way to regenerate power. As a light-footed driver—my daughter always complains that I'm hopelessly pokey—I did pretty well. After about 45 minutes in Wolfsburg traffic and country roads outside the city, with lots of starting and stopping, the meter told me that my average fuel economy was 8.4 liters per 100 kilometers, or 28 mpg.


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Posted by Orrin Judd at February 12, 2009 8:24 AM
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