The Aspen Hybrid is considerably more frugal. It shares its two-mode hybrid system with the Dodge Durango Hybrid. It's similar to the hybrid systems used on the new full-size SUV and pickup hybrid models from General Motors. In fact, this two-mode hybrid system was developed jointly by BMW, GM, and Mercedes-Benz. Chrysler's system uses an electrically continuously variable transmission (ECVT) paired with Chrysler's 5.7-liter Hemi V8. The ECVT has two electric motors and four fixed gears, and it can also power the Aspen like a regular CVT, meaning it offers an infinite range of gear ratios. The system's Traction Power Inversion Module (TPIM, of course) determines when the vehicle should operate in the first or second mode. In other words, a computer helps control whether the battery or the gas engine is doing most of the work depending on the situation and what you're doing with the gas pedal. The first mode is mostly for around-town driving and can use battery power alone up to 25 mph. The second mode is meant for highway speeds and always uses engine power. The system determines the necessary torque for the driving conditions and instructs the engine and electric motors to respond accordingly. No engine speed changes are necessary for mode shifts to occur. In the Hybrid, the Hemi V8 also has the multi-displacement system, and Chrysler says the hybrid system allows the Aspen to use just four of the eight cylinders more often for even better fuel economy.
Fuel economy for the Aspen Hybrid is estimated at 19/20 mpg City/Highway. That compares to 13/19 mpg for an Aspen AWD model. (The Hybrid comes with all-wheel drive.) Obviously, the big gain is around town and at lower speeds where you can run solely on the electric motors. Chrysler says the hybrid system boosts city fuel economy by 40 percent and overall fuel economy by more than 25 percent. So it's going to get better fuel economy in L.A. and Boston and other urban areas than it will in Montana and other wide-open or mountainous places. Total power output for the Hybrid is 385 horsepower and 380 pound-feet of torque. The Hybrid is rated to tow 6000 pounds. That's significantly less than the 8,900-pound rating possible in an Aspen, but a 6,000-pound trailer is a hefty trailer. That may be enough tow rating for you while giving you the benefits of good fuel economy during the majority of the time when you're not towing.
We found the hybrid system worked well, but not seamlessly. It occasionally stutters or clunks slightly as it shuffles modes. We noticed a flat spot in the power curve at about 45 mph, though it wasn't noticeable when we went easy on the throttle. Despite these quibbles, the Aspen's hybrid system is mostly transparent in operation, and you have to pay careful attention to tell that you're not driving a regular gasoline model. Your passengers may or may not notice anything unusual, especially if the radio is on.
On the road, the Hybrid powertrain may be slightly quicker than the standard Hemi version, though it's hard to tell. Any additional power the hybrid system provides at low speeds is offset by the sometimes tardy operation of the ECVT.
Towing with the Aspen is eased by a feature Chrysler calls Trailer Sway Control. This system senses trailer sway and employs the electronic stability control to apply tiny amounts of brake pressure selectively to individual wheels and to reduce engine torque to counter trailer-induced yaw. Next Page