PORTLAND, Me. -- Visitors strolling along the rocky Maine coast at Fort Williams State Park in Portland do not seem to notice anything unusual about the Chrysler Aspen sport utility vehicle we're steering on the meandering Ocean Road, but this particular Aspen, despite the exterior package of a conventional large-scale five-door SUV, is actually quite special.
It happens to be a new high-mileage hybrid electric vehicle (HEV) which carries a two-mode hybrid propulsion system and a wagonload of sophisticated electronic hardware.
Chrysler constructs this HEV-SUV off the Aspen, a truck-based sport utility in the full-size and half-ton class, and makes an equivalent model for Dodge as the Durango Hybrid.
The HEV version of Aspen (or Durango) looks virtually identical to a conventional Aspen (or Durango), save for some hybrid badges in chrome and green paint on fenders and tailgate.
Riding on a chassis constructed with hydroformed boxed rails for platform rigidity, Aspen stretches more than 16 feet long from the tip of the prow to the trailing edge of a tailgate and it's well over six feet wide and six-plus-feet high at the rooftop, with a wheelbase length almost ten feet long.
Such dimensions forge a big structure with the cabin space of a full-size SUV and plenty of room to install three rows of seats for up to eight adult passengers.
The dramatic exterior design for Aspen disguises the bigness of its passenger compartment by fashioning a bold but blunt prow preceding an upright structure and chiseled-block body.
Aspen's silhouette shows brief overhangs in front and back, bold wheel arches on flanks and a windshield tipped to the extreme to enhance aerodynamic efficiency.
Up front there's a dominating egg-crate grille in chrome that's followed by a sculpted hood scored by lines strafing across the top.
Below the strafe-lined hood this wagon houses a strong but efficient hybrid-type powertrain.
The prime component is a powerful new 5.7-liter HEMI V8 engine that runs on regular (87 octane) unleaded gasoline.
It generates up 345 hp at 5300 rpm and loads of torque to 380 lb-ft at 4200 rpm.
But Aspen Hybrid also carries additional power sources.
Included are two 300-volt synchronous electric motors which muster 87 hp each plus 235 lb-ft of torque.
These electric motors are packaged with planetary gearsets and hydraulic wet clutches as components of a new electrically variable transmission (EVT).
A sophisticated electronic control unit manages all energy produced by the on-board gas/electric engines and applies it directly to Aspen's four wheels in infinitely variable measures, as well as providing four fixed-gear ratios so the operation mimics a conventional automatic transmission.
Power to run the two electric motors flows from a nickel-metal hydride battery pack which is housed in Aspen's cabin below the second-row bench seat.
These batteries also store energy produced during regenerative braking and may be charged by the V8 engine with one of the electric motors working as a generator.
All of this high-tech apparatus for Aspen Hybrid is described as a two-mode hybrid propulsion system.
At low speed Aspen Hybrid can move forward or backward using one of the electric motors or the gas-fired V8 or a combination of the V8 and electric motor.
At highway speed the second mode works with all eight cylinders of the gasoline engine pumping when commanded, or with only four cylinders firing through Chrysler's MDS (multi-displacement system) technology for conserving fuel when V8 strength is not needed.
And when the HEV-SUV stops, the V8 engine shuts down, leaving only electric motors running.
The point of using all of this equipment on a big SUV like Aspen is to trim the powertrain's fuel consumption.
Tests indicate that Aspen Hybrid earns fuel economy figures up to 20 miles per gallon for highway runs and 19 mpg for in-town driving.
For a big SUV that stretches more than 16 feet long and tips the scales at close to three tons, these fuel economy scores seem huge -- representing a 40 percent improvement for city driving over a conventional Aspen with a 5.7-liter HEMI V8 aboard.
Still, Aspen Hybrid delivers strong muscle numbers.
Total estimated combined output of the two-mode hybrid system tallies to 385 hp and 380 lb-ft. of torque.
And the HEV's trailer tow rating climbs to 6000 pounds.
Aspen Hybrid stocks a four-wheel-drive (4WD) traction system with the transfer case using a 48-52 percent torque split between front and rear axles.
Layout of the cabin shows bucket seats up front with a bench for three on the second row and a three-seat bench on the back row that splits 60/40 percent.
The rear cargo bay contains 20 cubic feet of space with all seatbacks up. With third-row seats down, stow room grows to 68 cubic feet, but with second-row and third-row seats folded, the vast compartment measures to 102.4 cubic feet with a flat cargo floor that's 48 inches wide between the rear wheelhouses.
Also, Aspen's passenger compartment is laced with the trappings of a luxury vehicle.
Standard cabin features range from air conditioning and power controls for windows and door locks and exterior mirrors to a leather-wrapped steering wheel and premium leather-trimmed bucket seats with internal heat elements and power controls, wood veneer trim streaking door panels and the dashboard center stack, a LED (light-emitting-diode) interior lighting system with front and rear reading lamps pivoting for individual control, and a new Uconnect phone device utilizing Bluetooth technology for downloading phone book entries from supported phones.
Safety equipment for Aspen Hybrid begins with a disc brake in place at every wheel and linkage to a standard anti-lock brake system (ABS) plus a non-skid device dubbed electronic stability program (ESP). Curtain-style side air bags are concealed above windows for all three rows of seats with roll sensing -- the electronic roll mitigation (ERM) equipment. Further, there's the ParkView rear back-up camera aboard with ParkSense rear back-up detection system and a tire pressure monitoring system (TPMS).
Chrysler sets the MSRP for Aspen Hybrid at $44,770.