ABG First Impressions: Two-Mode hybrid Dodge Durango/Chrysler Aspen

Click the photo for a high-res gallery of the Durango and Aspen hybrid prototypes

Yesterday morning, AutoblogGreen had the privilege of being the very first media outlet to drive Chrysler's upcoming hybrid SUVs. We already knew that DaimlerChrysler was partnering with General Motors and BMW to develop the Two-Mode hybrid system that we drove last month on the Chevy Tahoe. Chrysler's first hybrid application will be on the Dodge Durango and Chrysler Aspen.

The Chrysler SUVs are still about a year away from start of production and aren't yet to the same stage of development as the GM vehicles. In fact, by the time the Chryslers hit the market, GM will have the Tahoe/Yukon/Escalade, the Sierra/Silverado pickups and the Vue crossover all available for sale with the Two-Mode system.

Read ABG's initial driving impressions of the Two-Mode Durango after the jump
The configuration of the hybrid system on the Durango is pretty much like what GM did on their big trucks with only one engine combination mated to the Two-Mode transmission. The transmission is the same unit GM is using, but Chrysler has their own control software. To recap, the electronically controlled planetary gear continuously variable transmission has two liquid cooled electric motors integrated into the unit.

In addition, the clutches in the transmission allow for four fixed forward gears for higher speed driving. The unique second mode of the system allows the clutches to provide a direct mechanical drive path to send torque straight to the wheels without going through the motors. This allows for greater highway efficiency than other strong hybrid systems. Reverse drive is provided entirely by the electric drive with no reverse gear being incorporated into the transmission. If the battery charge level is too low, the engine will start just to charge the battery.

Like the Tahoe, the nickel metal hydride battery pack is mounted underneath the second row seat and is unobtrusive. Unlike the GM vehicles, which will offer both rear and all-wheel-drive versions, Chrysler will only offer all-wheel-drive with the hybrid. The stated reason for doing this is to maximize the regenerative braking capability by capturing the kinetic energy from all the wheels.

The two vehicles that Chrysler brought out for us to drive are still at least three prototype levels away from the production version. Given the relatively early stage these vehicles are in the driving opportunities were limited, with a loop of the Ride Road at Chelsea and some low speed driving to check out the EV mode. The powertrain worked smoothly and without any hiccups. Like GM, Chrysler has taken advantage of the hybrid system to expand the range of use of the MDS cylinder shut-off mechanism on the 5.7L Hemi V-8.

During the short drive the only problem area that showed up was in the brakes. During deceleration it was possible to feel some changes in deceleration at the system transitioned between regen and friction braking. With a year to go before production, software updates to the brake system should definitely iron this out. As for the hybrid drive system, transitions between electric drive, four cylinder and eight cylinder modes were completely seamless just as they were on the Tahoe. Unlike the four-cylinder hybrid systems that I've tried, the engine startup was imperceptible except for the muted sound of the Hemi.

At this point there are no cosmetic differences between the hybrid and conventional Chryslers, but that also may change. As with the GM hybrids Chrysler is projecting a fuel efficiency improvement of twenty-five percent overall and forty percent on the highway in the city. After driving the truck I spoke to Anreas Truckenbrodt who is the Executive Director of the hybrid development center. As always he was reluctant to talk about future unannounced products, but he did acknowledge that the two-mode system will move beyond the Durango/Aspen in the Chrysler lineup, and that the company is actively working on a mild hybrid system for lower cost applications as well.

Ford may have been the first domestic to get a hybrid to market with the Escape and they do have the Fusion/Milan coming soon, but they haven't shown or talked about anything in the larger vehicles. Along with GM, Chrysler is well on its way, and Ford would be wise to get something going on the Expedition and their large crossovers soon.

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