2009 Mercury Mariner Sport Utility Crossover

FORT LAUDERDALE, Fla. -- Not a cloud clots the vivid blue sky above Florida's Gold Coast in Fort Lauderdale as we troll the beach-bordered route A1A, South Atlantic Boulevard, driving at a snail's pace in the far right lane with traffic stacking up behind us.

Our slow-go intent is not to frustrate other motorists on the thoroughfare but to figure out exactly how high we might influence the miles-per-gallon fuel consumption numbers along a measured route while steering a new version of the hybrid electric vehicle (HEV) from Mercury. This HEV, looking elegant in a sculptured package with crisp lines and a distinctive prow trimmed in smooth satin-finish metal, is derived from Mercury's unibody-based Mariner crossover utility vehicle.

Its nameplate is self-explanatory -- Mariner Hybrid. The HEV looks virtually identical to a conventional Mariner as a four-door CUV for the compact class, although the two-box body shell effectively conceals a hybrid powertrain nestled below Mariner's squared front hood that's not conventional at all.

You see, there's not one but two motors aboard. There's a new fuel-efficient 2.5-liter four-cylinder engine that sips gasoline plus a battery-powered electric traction motor of permanent-magnet design.

The electric motor is capable of propelling the wagon by itself, or it can work in concert with the gasoline engine to deliver a power boost that's equivalent to the kick of a V6.

An electronic control module aboard the wagon manages all energy produced by the two plants and applies it directly to the front wheels -- or to all four wheels for the optional all-wheel-drive (AWD) version -- in infinitely variable measures through an electronically controlled continuously variable transmission (eCVT).

Virtually silent at start-up with only the electric motor switching on, the Mariner Hybrid leaps forward on command with help from the electric motor, which can propel the wagon up to 25 mph. When more power is needed, a generator cranks up the gasoline engine in only a fraction of a second. At highway speeds the gas-drinking engine does most of the motivating, while in reverse gear it's the electric motor that handles all of the work, and the electric motor also serves as the primary plant in stop-and-go traffic on city streets where a gas engine is inefficient.

Power from the gasoline engine is utilized in two different ways. One portion of this energy is used to turn the wheels, while another portion powers an electric generator that runs the electric motor, which in turn sends the supplemental power to the wheels.

Stomp the accelerator to romp into a passing lane and the electric motor adds an extra boost, yet for such a heavy demand of power the operating energy for the motor comes directly from a bank of on-board batteries.

Internal recharging occurs either during braking, when the gas engine operates as a generator, or when the electric generator does the recharging job. Thus, a Mariner Hybrid never needs to be plugged in for recharging as would a purely electric vehicle. The new four-cylinder gasoline-fired plant, with dual overhead cams and intake variable cam timing (i-VCT) plus modifications for fuel-efficient combustion under the Atkinson-cycle concept, develops 153 hp at 6000 rpm plus torque of 136 lb-ft at 4500 rpm.

The 330-volt electric motor, tied to a nickel-metal hydride battery, kindles power measured in kilowatts, but it's the approximate equivalent of 94 hp at 5000 rpm.

Adding the hybrid technology to Mariner produces a CUV which earns uncommonly high fuel economy numbers but also dramatically pared tailpipe emissions such as unburned hydrocarbons (HC) and oxides of nitrogen (NOx).

Fuel economy figures rise to 34 mpg for running on city streets, and the reduced emissions qualify the wagon for the stringent Advanced Technology Partial Zero Emissions Vehicle (AT-PZEV) standard.

Actually, Mariner Hybrid achieves better fuel efficiency when driving on city streets in start-and-stop traffic rather than when cruising at a swifter pace on a highway. That's because in city traffic with frequent stops the electric motor takes over more often. Our own fuel economy test, conducted over a 20-mile loop coursing through Fort Lauderdale, generates an impressively tall fuel consumption number -- 45 mpg.

The caveat is that we use every trick to conserve fuel, from putting a feather touch on the accelerator to coasting on downgrades and riding the brakes for battery recharging, and we become a nuisance in traffic due to our slow pace. For normal navigation in town traffic or at speed on a freeway, our drive brings lower numbers -- 32 mpg or so.

Still, such figures are well above the ratings of a Mariner with the conventional four-cylinder engine tied to a six-speed automatic transaxle -- it scores about 20 mpg for city driving and 26 mpg on the road. Adding optional AWD traction trims the fuel numbers on Mariner Hybrid, but not too much (29/27 mpg city/highway).

Mariner's AWD mechanism is a smart traction system that distributes power between front and rear wheels selectively as changing conditions of road or trail may warrant -- the intent is to maintain a firm tire grip no matter what happens on pavement or dirt.

The package design for Mercury's gas/electric CUV is fresh to forge a tougher look in a chiseled design with a sloping and stepped front hood, a high beltline and big wheels and tires as emphasized by flared wheel arches. A bold face features Mercury's vertical-bar grille in satin-finish metal and corner cluster headlamps set above tilting squares of foglamps planted in the fascia.

Regarding safety measures for the CUV, front riders have dual two-stage frontal air bags plus seatbelts with load-limiting retractors and buckle pretensioners, while in the rear there are anchors to tether a child's safety seat. Side-impact air bags mounted on outboard front seats and curtain-style air bags concealed in headliners above front and back rows are also on tap as new standard gear.

Equipment promoting active safety includes the quick all-electric power assist steering through a direct rack and pinion system and four-wheel disc brakes tied to an anti-lock brake system (ABS) plus the AdvanceTrac electronic stability control device with Roll Stability Control (RSC). Entry MSRP for Mariner Hybrid comes to $30,090.