While Green Fuels Forecast was in Germany last fall to try out the new 2010 Golf, VW pulled out one of its prototype Touareg hybrids for us to sample at the track. Just as GM did with its Two-Mode hybrid SUVs, Volkswagen has opted to add hybrid technology to its thirstiest vehicles first based on the premise that the fuel savings will be the biggest. Another parallel with GM's approach is the decision to maintain all of the capability of the same vehicle with a conventional powertrain. Let's take a look at the Touareg hybrid after the jump.
While General Motors opted for a highly optimized version of its 6.0-liter V8 for its hybrid trucks, Volkswagen is instead using one of the newest engines in the group in the Touareg. The new 3.0-liter TSI V6 debuted in 2009 in the Audi A6 and S4. The new hybrid gets the engine in the more powerful 333 horsepower / 324 pound-foot form used in the sporting S4. VW gets this output from a comparatively small engine through a combination of direct fuel injection with a mechanical supercharger. Even before factoring in the hybrid system, the V6 already benefits from the advantages of engine downsizing. The six cylinder engine has output on a par with the larger 4.2-liter V8 also offered in Touareg, but in more efficient package. In addition to the smaller displacement, the engine also features other enhancements like a water pump that can be switched off during engine warm-up. This reduces the parasitic draw while speeding up the warm up.
For the electric drive portion VW and Porsche have opted for a modular design approach with this hybrid. The two-mode system integrates a pair of motor-generators into an electronically variable transmission, creating a very complex and expensive piece of hardware. The Touareg's powertrain uses a conventional 8-speed planetary gear automatic transmission with an electric motor module sandwiched between the engine and transmission. A clutch between the engine and motor allows the V6 to be completely de-coupled from the powertrain for electric only operation. The motor adds 38 kW and 221 lb-ft of torque to the V6 with the combined output of the system being limited to 369 hp and 406 lb-ft of torque.
The besides providing tractive force and regenerative braking capabilities, the motor also supplants the standard alternator on the Touareg. Using the motor/generator to provide the 12 volt energy needed by the vehicle's electrical system further reduces the parasitic losses and improves the noise, vibration and harshness of the vehicle. The end result should be a hybrid SUV that is significantly faster than the GM hybrids while actually improving on some of the capabilities that SUV customers expect from this type of vehicle.
Our time at the wheel of the Touareg was limited to a couple of laps of the short loop at the Oscherlaben Motorpark. Start up was pretty standard and like every other hybrid there is a power-flow display in the navigation screen to let the driver monitor where energy is going while driving. A gentle touch on the throttle can get the Touareg rolling away silently drawing energy only from the battery pack. That pack is mounted under the rear cargo floor and is filled with nickel metal hydride cells supplied by Sanyo, the same supplier that currently provides cells for Honda and Ford hybrids. The pack has a capacity of 1.7 kWh, higher than most such hybrids which should allow it to provide even more electrical boost and propulsion capability.
Pressing harder on the accelerator pedal gets the combined output of the engine and motor working together to yield surprisingly brisk acceleration. Volkswagen claims 0-62 mph in just 6.8 seconds, and our seat of the pants evaluation declares this to be entirely plausible. The prototype that we had the opportunity to drive was built in January of 2009 and had control software that was locked in sometime prior to that. Unfortunately, VW has opted not to update the software in this particular evaluation unit and VW claims it is not the final production calibration. We found that as the Touareg switched between different control modes such as electric, boosted and internal combustion drive, the transitions were not as seamless as we have come to expect with other contemporary hybrids. The GM hybrids in particular have much more transparent engine on-off toggling.
Again like other hybrids, the Touareg has an electro-hydraulic brake system that allows for blending of friction and regenerative braking. With the moderate applies typical of most daily driving, the pedal feels fairly firm and linear. However, a harder apply reveals the artificial nature of the pedal resistance which no one seems to have been able to completely eliminate. There is plenty of room for modifying this behavior in the software calibrations so we'll reserve final judgment on the overall feel of the powertrain and brakes until we get our hands on a production intent unit sometime later this year.
In addition to the strong acceleration, VW claims the Touareg can tow up to 7,716 pounds matching both the gas and diesel engined models. That's significantly better than the GM hybrids which depending on configuration max out at 6,100 pounds. Another advantage for Touareg is fuel efficiency. VW is claiming the prototype averages better than 26 mpg (US) on the NEDC driving cycle, about 1 mpg better than the current Touareg TDI V6. That's about 6 mpg better than the AWD Tahoe hybrid. When compared on the more conservative EPA driving cycles that number will likely drop to about 22-24 mpg, still an excellent result for an SUV with this kind of performance.
The engineers at VW and Porsche are still working on the final calibrations for the Touareg and Cayenne hybrids but those should be completed in the very near future. VW officials told us that production of the two hybrids will begin in early 2010 at the group's plant in Bratislava, Slovakia. The Slovak plant builds complete Touaregs and Q7s as well as the body shells for the Cayenne. The Cayenne bodies are then shipped to Porsche's Leipzig plant for final assembly. Both the Touareg and Cayenne hybrids will go on sale in the first half of 2010. It's too early to talk about pricing, but it's probably safe to assume the Touareg hybrid will start somewhere closer to the $49,000 price of the current V8 than the $43,000 sticker for the TDI. The Cayenne with exactly the same powertrain will no doubt command a substantial premium over any model with a VW badge.