Editor of greencarreports.com Marty Padgett spends the day with Volkswagen, driving new models, learning about advanced technologies, and quizzing executives. Here's his preview of VW's upcoming Touareg Hybrid sport utility vehicle.
Volkswagen will launch a hybrid electric model of its Touareg sport utility vehicle late in 2011, as a 2012 model. The hybrid comes a year after the launch of its all-new 2011 Touareg next year, one of three related hybrid sport utilities from the German automaker.
The hybrid Touareg will share a basic platform and some battery technology with the 2011 Porsche Cayenne Hybrid, which is to launch late next year and will introduce the completely redesigned second-generation Cayenne. Completing the trio, Audi will offer a hybrid version of its Q7 sport utility as well.
Test track laps
We got to take a few brief laps around VW's test track in an early development prototype, based on the current Touareg. A fairly standard dashboard display showed power shifting among the engine, the battery pack, the electric motor, and the regenerative brakes.
The new powertrain pulled strongly in the old body, although the engineer riding along acknowledged the stuttering in transmission downshifts. Getting the transitions right has always been one of the hardest hybrid engineering tasks.
One unique feature: If the Touareg Hybrid is parked and running only on battery power, the engine will switch on as a cue to remind the driver the vehicle is already powered up whenever a door is opened.
The nickel-metal-hydride battery pack is housed under the rear cargo floor, leaving space for luggage above. The whole hybrid system, including the pack, the electric motor, and associated power electronics and cables, adds about 440 pounds to the vehicle.
Simpler system than Toyota
The Touareg Hybrid will feature a direct-injected, supercharged 3.0-liter V-6 engine rated at 333 horsepower, with a 38-kilowatt (52-hp) electric motor located between the engine and a new eight-speed automatic transmission. The engine's the same one found in the 2010 Audi S4.
While VW's system is a full hybrid, meaning it is capable of powering the car solely on electricity, it is far simpler than the Hybrid Synergy Drive system used by Toyota in its range of hybrid electric vehicles. It's also simpler than the sophisticated Two-Mode Hybrid used in both the Mercedes-Benz ML450 Hybrid and the BMW X6 ActiveHybrid sport utilities.
This means, however, that while the VW system can run on electric power and recharge the battery pack, it can't do both at the same time.
Gains: 7 to 10 percent
The electric motor produces 221 lb-ft of torque, two-thirds as much as the engine itself. It is tuned to provide maximum economy on the open road, rather than in the urban settings most suited to other hybrids like the 2010 Toyota Prius.
Volkswagen says conservatively that it expects gas mileage to improve by 7 to 10 percent over the non-hybrid V-6 version of the new Touareg. The fuel efficiency increase over the V-8 version, of course, will be higher.
Sailing along...toward lithium-ion
In the Porsche version, a unique hydraulic clutch shuts off the engine under light loads. Engineers have called the resulting electric drive "sailing," for the silence sensation of speed powered only by the nickel-metal-hydride battery pack.
At the test day, the company also discussed its Volkswagen Golf TwinDrive hybrid project, which puts plug-in technology in the body of the new Golf.
More distant hybrids and electric cars from Volkswagen, including an electric version of its Up mini-car, will move to lithium-ion battery packs, which hold roughly twice as much energy per pound as the Touareg's nickel-metal-hydride pack.
Company engineers said Volkswagen didn't see the point of plug-in series hybrids such as the 2011 Chevrolet Volt, which run exclusively on battery power over shorter distances and use the engine only to recharge the battery.
VW claimed that using a gasoline engine to run a generator to charge a battery pack wastes 20 percent of the energy (although conventional gasoline cars convert only about 25 percent of the energy stored in their gas tanks into torque to move the vehicle).
source: greencarreports
