CONSUMER REPORTS: Truths and trade-offs of high-MPG cars
Electrics, hybrids, diesels and even some of the latest conventional cars can not only help you save money, but also cut emissions and reduce our country’s dependence on imported oil. The auto experts at Shop Smart, the shopping magazine from the publisher of Consumer Reports, recently looked at the pros and cons of five major types of high-mpg cars.
How they work: Most hybrids use a small, four-cylinder gas engine in tandem with an electric motor that’s powered by a large lithium-ion battery. The car moves by electric power, gasoline or both, depending on driving circumstances. The battery is charged by the gas engine while you’re driving and through regenerative braking, which recaptures energy while slowing down.
Pros: Hybrid vehicles are usually among the most fuel-efficient in their size categories. Many rank as some of the most reliable cars on the road. Fuel use in city driving can exceed 40 mpg.
Cons: You may pay a premium for a hybrid. Batteries can eat up cargo space. Batteries should last 150,000 miles or more, but out-of-warranty battery replacements can be pricey.
How they work: Plug-in hybrids, such as the Toyota Prius Plug-in and the Ford C-Max Energi, work like regular hybrid cars but with a larger drive battery that lets them operate on electric power for longer periods of time to save money.
The Chevrolet Volt is essentially an electric car that uses a small gas engine as a generator to maintain the battery and let you keep driving when the battery is depleted. ShopSmart’s testers got about 35 miles before the battery lost its charge.
Pros: They reduce your gas usage without the range limitations of a dedicated electric car.
If you have a short daily commute and can recharge daily, you might be able to go days in the Volt without using any gasoline.
Cons: High initial cost. (The Volt, for example, starts at $39,145.)
An out-of-warranty battery replacement could be very costly. The large batteries may greatly reduce cargo space.
How they work: Electric vehicles (EVs) use one or more electric motors to turn the wheels and a high-capacity battery to power those motors. When the battery runs down, you plug in the car to “refuel.” Depending on the model, that can take 12 to 18 hours using regular 120-volt household current or 4 to 8 hours with a higher voltage 240-volt charger that may be purchased separately.
Pros: No more stops at gas stations. The cost per charge is very low compared with filling a gas tank. Ideal for round-trip commutes of under 30 miles.
Cons: Relatively expensive. The range is limited, often less than 100 miles per charge. Cold weather can shorten the driving range by a third to a half. Charging takes from several hours to 12 or more. Range limitations and charging times make long trips impractical.
A diesel is a heavy-duty engine that works at much higher temperatures and pressures than a gas engine does, which translates into greater efficiency. Diesel fuel, very similar to home heating oil and jet fuel, is much cleaner than it used to be, and anti-pollution devices in the exhaust system further cleanse noxious pollutants.
Pros: About 30 percent better fuel economy than a similar gas-powered vehicle. The highway mpg is especially good. Long driving range per tankful, sometimes 800 to 1,000 miles.
Cons: Acceleration is often slower than with an equivalent gas engine. Diesel is more expensive.
Some regular gas-powered cars are getting amazing mileage thanks to reduced weight, improved aerodynamics and more efficient engines and transmissions.
Pros: Excellent mpg without the extra cost of a hybrid or diesel. Some midsized sedans that use the latest fuel-saving technologies are as efficient as subcompact cars.
Cons: Even the most efficient conventional cars can’t provide the fuel economy of the best hybrid and diesel models.