How green is my highway
Marc Stengel, Thu, 18 Aug 2005 08:00:00 PDT
If I say "hybrid" and everyone but teenagers blinks their eyes, I know I'm standing at the dawn of an automotive revolution. Although the handful of present-day hybrid automobiles represents varying combinations of gasoline-fueled internal combustion and battery-powered electric propulsion, this concept seems to confuse certain folks above a certain age-born, say, before the mid-'60s.
The confusion stems from a very distinct "change of paradigm." Hybrids, like the innovative 2005 Ford Escape Hybrid SUV, are collections of recognizable components, such as an electric motor and an internal-combustion engine; but these components are put to use in disconcertingly unrecognizable ways.
Sometimes, for example, the gasoline engine simply charges a giant battery pack consisting of 250 nickel-metal-hydride D-cells located under the floor of the rear cargo hatch. Sometimes, on the other hand, the gasoline engine provides supplemental acceleration to supplement the exertions of a 330-volt permanent-magnet AC electric motor. And sometimes the gasoline engine simply sends its power, directly and exclusively, to the wheels.
With a hybrid, things aren't always what they seem. The four-wheel disc brakes aren't just for slowing down and stopping; they're also for producing "regenerative" power that converts vehicle deceleration into battery-charging electric current. This system, moreover, operates in coordination with a continuously variable (i.e., gear-less) transmission (CVT) that mixes and matches acceleration, deceleration, electric power and gasoline power as conditions require.
One particularly clever-and beneficially misleading-trick is this Escape Hybrid's "interpretation" of brake-pedal use. If, at cruising speed, the driver gently depresses the brake pedal to lower speed, the drive-by-wire braking system actually slows the SUV down initially by gearing down and diverting power to an electric generator. The brake pads aren't even applied until firmer pressure on the pedal indicates a desire to slow abruptly or to stop altogether.
This saves wear and tear on brakes and charges batteries; but in the case of Ford's new hybrid, it also results in a bit of brake pad shudder when the Escape nears a complete stop-a function, presumably, of the pads' relative infrequency of use.
Oh, and by "complete stop," I mean literally that. When you halt at a stop sign or traffic signal, the Escape Hybrid shuts down completely and automatically. The eerie quiet is uncanny; and if you lift your foot off the brake without depressing the accelerator, the Escape whisks forward in total silence under solo-electric power. Then, as soon as you punch the accelerator again, the gasoline engine fires promptly (within 400 milliseconds, in fact), and you're electro-petro-mechanically under way yet again.
The illusions (and delusions) continue. Take that primitive concept of "horsepower," for instance. According to Ford's specs, the twin-cam, 2.3-liter gasoline engine is good for 133 hp and 129 ft.-lbs. of torque. The electric AC motor generates the equivalent of 94 hp. But instead of 227 hp of total power to the wheels, Ford admits to a maximum of only 155 hp. The remaining 72 hp-almost one-third of the total-is drawn off by "the system" (e.g., charging batteries, starting the engine, generating cabin electricity, etc.)
This mathematical sleight-of-hand carries over to fuel-economy ratings. They're topsy-turvy, to say the least. The Environmental Protection Agency recognizes the Escape Hybrid's fuel economy for city driving as 36 mpg-best among SUVs, by the way, although only 12th-best among all U.S.-sold vehicles. On the highway, however, the Escape Hybrid gets just 31 mpg, contrary to traditional expectations. And yet Ford admits in its own press materials that the Escape Hybrid's 15-gallon gas tank is good for 400 miles of city driving-or 26.67 mpg.
What gives? In a phrase, "driver input." Even more so than with a traditional vehicle, the mileage performance of Ford's new hybrid is super-sensitive to habits of accelerating, braking, coasting and cruising. As if to prove the point, there's a fascinating, animated flow chart display in the dash that instantaneously reports whether the vehicle is making or consuming power, where that power is coming from, where it's going and how much.
Upon first driving the Escape Hybrid, it doesn't take long before this passive display become an interactive tutor, coaching the driver how best to minimize consumption of fuel while maximizing production of electricity by coasting and braking. For the Game Boy Generation, driving this way is a blast. For the Etch-a-Sketch Gang, on the other hand, adapting driving habits to a computerized graphic is a nuisance. You can probably guess what vintage an Escape Hybrid driver is, in other words, by the mileage results turned in.
You can say the same about the pay-now-or-pay-later aspect of hybrid vehicle economics. It's one thing to get decent city mileage in the mid-30-mpg range with a compact SUV. It's another thing to pay through the nose for that privilege. By way of illustration, consider the price and mileage of the Escape Hybrid compared with the all-gasoline Escape XLT V6.
The XLT costs $3,385 less (base price) and gets 22.5 mpg (combination city/highway). Where gas costs $1.90 per gallon, it would take 243 fill-ups to recoup the hybrid's extra cost in fuel economy savings. For gas at $2.42 per gallon, as in California at present, break-even comes after 191 fill-ups. Even if you forced yourself to gas up once a week (and that's a lot of driving), it would take four years, eight months or three years, eight months, respectively, to justify the Escape Hybrid's higher price.
For some folks, that's a heck of a lot of force-feeding just to make an environmentally sensitive point. And yet for others, it's simply the price of going green. Or, as is true for every generation since time immemorial, it takes green to make green.
2005 Ford Escape Hybrid; 5 pass., 4-door; FWD (AWD opt.), 2.3 DOHC "Atkinson-Cycle" inline-4 plus 330-volt AC motor; 155 combined hp; 36 mpg/City, 31 mpg/Highway; cargo: 27.6-65.5 cu. ft.; tow: 1,000 lbs.; base price: $26,380; as-tested, incl. four-wheel ind. suspension & ABS disc brakes, 16-in. wheels; Safety Canopy front/front-side/front-rear-curtain airbags; GPS navigation, 110-volt AC power inverter: $30,825.