Invasion of the Green Machines
High gas prices have drivers chasing after hybrids. Is it a fad or a phenom?
In the Market?
You can find Richard J. Newman's Test Track reviews of hybrids and other cars at www.usnews.com/auto
Under the Hood
Hybrid vehicles combine electric motors and rechargeable batteries with a conventional gasoline engine to boost mileage as much as 40 percent. Here's how most models work:
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To save fuel, the gas engine shuts down when the car coasts or comes to a stop. But it restarts immediately once the driver hits the accelerator for a passing maneuver or needs power for some other reason.
The electric motor drives the car at low speeds, where internal-combustion engines are least efficient. The gas engine kicks in as the car accelerates, and it does most of the work at highway speeds.
The sealed battery pack powers the electric motor and recharges automatically. Its size is one of the few disadvantages of a hybrid, since it often robs as much storage space as a spare tire. Most battery packs are guaranteed to last at least 100,000 miles.
The heat energy generated by the brakes is captured and used to recharge the battery pack. This "regenerative braking" helps make hybrids ideal for stop-and-go city driving.
Hybrids often have other design features meant to reduce weight or drag, such as stiffer tires inflated to a higher pressure.
Sources: Ford, Toyota, Honda, Union of Concerned Scientists, HowStuff Works.com
Is it worth it?
Honda Accord Hybrid V-6
Base price: $30,140
Average mileage: 32 mpg
Annual fuel cost $967
Average cost to own: 52 cents/mile
Honda Accord EX V-6
Base price $26,850
Average mileage: 24 mpg
Annual fuel cost $1,289
Average cost to own: 48 cents/mile
Note: Cost-to-own figures are for the midwestern U.S.
Sources: Edmunds.com, www.fueleconomy.gov, Honda