Hybrids: Need-to-Know Info to Make the Right Choice
Today's hybrid vehicles offer fuel efficiency, fast payback and, perhaps most important, a much-needed boost for the environment.
By Christopher Yeich
Posted October 30, 2007, at 1 p.m.
With fuel efficiency and eco-friendliness top of mind among today's drivers, automakers are responding by bringing to market more hybrid automobiles that save dollars at the gas pump while also helping Mother Nature.
Today's most popular hybrids use a combination of electric motor and internal combustion engine (ICE) technologies, the latter of which can run on gasoline, ethanol or diesel fuel. The result is an easy-to-maintain vehicle that maximizes fuel economy, reduces oil consumption and fuel expenditures, and helps lower environmentally harmful emissions.
The market includes several types of hybrids: full (or strong), mild, parallel, series and plug-in.
The most popular hybrids from Toyota, Lexus and Ford fall into the full category, using electrical power to begin moving the vehicle without consuming any gasoline. Mild hybrids, such as the Honda Civic hybrid, launch only if the ICE is engaged and use the electric motor to assist the engine when extra power is needed.
Parallel hybrids, such as the Honda Civic and Accord hybrids, use both the electric motor and gas engine to provide propulsion, while series hybrids use the ICE to power a generator, which can either charge the battery or power the electric motor to drive the transmission. Limited-range plug-ins enable drivers—via the option to recharge the battery by plugging it in — to do most of their close-to-home driving using only electricity. When the electric charge is depleted, a smaller ICE takes over and operates like a regular hybrid.
Employing Advanced Technologies
Regardless of type, hybrid automobiles all employ various advanced technologies, including:
- Automatic start/shut-off: Automatic start/shut-off prevents wasted idling energy. When the hybrid vehicle is approaching a stop sign or stop light and the driver's foot is taken off the accelerator and applied to the brake, the ICE shuts off as the vehicle coasts to a stop. The moment the driver takes his or her foot off the brake pedal, the engine starts up again. This reduces gasoline consumption and CO2 emissions.
Batteries: Though a conventional vehicle's lead-acid starter battery is rechargeable, it delivers only small bursts of current for short durations, using an alternator to supply power to systems and recharge the battery while the engine is running. A hybrid vehicle also uses a lead-acid battery, but additionally employs a far more powerful deep-cycle rechargeable battery that can be fully charged and discharged over and over, providing about 300 volts or more of power. This main battery is designed to last the lifetime of the car.
While battery development continues driving toward the optimum combination of long-range use, ease of charging and overall longevity, nickel-metal-hydride batteries are the ones most commonly used today in hybrid vehicles, affording lighter power density and lower weight than traditional batteries. Looking ahead, the industry is moving toward more efficient lithium-ion battery technologies, working to overcome past issues of overheating.
- Electric motor drive assist: The electric motor provides additional power for acceleration, passing and hill climbing. It also enables smaller, lighter-weight, more-efficient ICEs to be used. General Motors (GM), Honda and Toyota each has its own electric motor drive-assist systems, with each version functioning differently between full-hybrid and mild-hybrid offerings.
- Regenerative braking systems: These systems provide torque transfer and energy reclamation to the battery. When the brake pedal is depressed, the mechanical braking energy produced from friction and torque is transferred into electrical energy, which is stored in the rechargeable battery. When the accelerator pedal is depressed afterward, that stored energy is used to help launch the vehicle.
Eyeing Fuel Economy
All these technologies work together to help maximize fuel economy. Hybrids do get better mileage than their traditional vehicle counterparts; however, the mileage rating printed on a hybrid's sales sticker may not necessarily reflect real-world driving conditions. For instance, while a non-hybrid 2.4-liter Toyota Camry CE is rated at 24 miles per gallon (MPG) for city driving, Toyota's 1.5-liter Prius hybrid is rated at 60 MPG.
"In my experience, a Prius will get about 42 miles per gallon," says veteran automotive journalist and Blue Sky Productions president John McElroy, who hosts the weekly television program Autoline Detroit. "Forty-two is pretty good, but that's not what the label promises.
"The EPA recently lowered the fuel economy on all vehicles by about 10 percent to 12 percent — and on hybrid vehicles by about 30 percent — to make them more reflective of what happens in the real world. You will get better fuel economy with a hybrid, but chances are, with strong hybrids like the Prius or the Ford Escape, you're probably not going to get exactly what the label says."
McElroy makes another point about fuel economy: "In a strong hybrid, you will get better fuel economy in stop-and-go driving than you will cruising at a steady speed on the highway. This is due to regenerative braking: The more you stop and start, the more you're using the batteries versus the piston engine."
Sticker Price and Payback
Hybrids are more expensive than conventional cars due to the advanced technologies they employ, according to McElroy. He estimates the combined costs of the electric motor, battery pack and commensurate electronics in the full hybrid category can account for about $6,000 to $7,000 of up-front costs.
However, automakers point out that fuel savings — along with tax incentives and other rebates — can offset costs in the longer term and afford hybrid owners relatively quick payback. For example, in a Toyota cost comparison between its Prius and Camry hybrids and conventional Camry automobiles, hybrid payback is estimated by the manufacturer at between six and 10 months.
Drivers should also consider repair costs, such as battery replacement. "The track record for hybrids so far is good," says McElroy. He explains that while batteries in hybrids are built to last the lifetime of the automobile, at some point prior to that time they could give out.
"If the battery system fails, and you have to replace it at the dealership, you're probably looking at a $4,000 replacement cost. But no automaker wants to get a black eye on this technology, so if you have a problem with the battery right now, they'll probably replace it at no cost." Moreover, warranties on hybrids and components are generally the same as conventional cars but some warranties are long — up to 10 years and 110,000 miles.
Making the Right Choice
McElroy advises anyone considering a hybrid purchase to take into account personal driving habits along with fuel economy, environmental benefits and any pricing incentives. "If you do a lot of stop-and-go driving, a hybrid probably makes sense for you," he says. "If you do a lot of steady highway cruising, a diesel might be the best choice."
Beyond fuel savings, hybrids continue to provide tangible environmental benefits. These include the savings of close to 215 million gallons of fuel in the United States since 1999 (according to the National Renewable Energy Laboratory); approximately 3.5 million fewer tons of CO2 emissions since 1997 when compared to gasoline-powered vehicles in the same class (states Toyota Motor Corp.); and significantly lower total lifetime energy use of hybrid vehicles compared to non-hybrids — from development to production, on-highway use, end-of-life recycling and landfill (reports the Argonne National Laboratory).
In short, buying a hybrid can make sense both for the environment and the owner's budget.
Bio: Christopher Yeich is a senior editor/writer at Ziff Davis Enterprises. He has worked as a business-to-business editor for more than 18 years, and served as senior associate editor for Chilton's Automotive Industries magazine.
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