Hybrid Cars

While the Honda Insight and Toyota Prius introduced us to hybrid technology, they also introduced us to styling that was, well, unusual. But today, hybrids can easily be mistaken for internal combustion engine vehicles thanks to hybrid versions of the Honda Civic and Accord, Toyota Highlander, Ford Escape and Lexus RX that look nearly identical to their gasoline counterparts.

Hybrid vehicle sales increased from just 9,350 vehicles in 2000 to over 200,000 for the 2006 calendar year. About half of those sold in 2006 were Toyota Prius models, whose production run is now 100,000 units annually, the largest of any of the hybrids currently on the market. The more traditional styling, improved performance and soaring fuel prices have led to hybrids' popularity skyrocketing. Here's an in-depth look at what is making these vehicles sell and a little background on the hottest trend in fuel-efficient transportation.

Hybrids of Today and Tomorrow
In the seven years that hybrids have been on the market, we've seen an increase from two vehicles — a two-seater and a compact sedan — to 15 vehicles that come in almost every body style. Today, consumers have a choice of several sedans, SUVs, a luxury crossover vehicle and even light-duty pickups. (For information about every hybrid currently on the market, click here.)

Most automakers consider hybrids to be the first step on the long road to a transportation infrastructure that is less dependent on foreign oil. There is a general consensus that this road will eventually lead to hydrogen as a fuel source, which is clean burning and plentiful. Since there's a lot of ground to cover before hydrogen fuel is the norm, most automakers continue to focus on hybrid technology, while simultaneously planning for a hydrogen infrastructure in the long-term.

While Ford, General Motors, Honda, Lexus, Mercury, Nissan and Toyota all have hybrids already on the market and have plans to add even more hybrid models, Hyundai, Kia, Mazda, Mercedes-Benz and Mitsubishi have hybrid vehicles in development. In addition, Porsche, Subaru, Volkswagen and Volvo are all considering putting hybrid vehicles into production. (To learn more about future hybrid vehicles, click here.)

BMW has chosen not to get in the hybrid game so far, although the company is studying hybrid technology. Its primary focus, however, is on hydrogen and it is currently testing a small fleet of 7 Series models equipped with internal combustion engines that run on hydrogen. "We believe that, in the end, hydrogen is the solution," Tom Purves, chairman and CEO of BMW North America, said. "We will bring a hydrogen-fueled internal combustion engine to market sometime in the current generation of the vehicle," he said. "Clearly, there are a lot of external factors for this to happen, such as fueling stations."

How Hybrids Improve Gas Mileage
While some consumers buy hybrid vehicles because of the benefits to the environment, research indicates that the primary factor for most buyers these days is the improved gas mileage. All hybrids boast a significant improvement in fuel economy over similarly sized, comparably equipped, gasoline-powered counterparts, although the mile-per-gallon average that hybrid owners see can vary quite widely, depending on driving style and whether travel is mostly in the city or on the highway.

The improvement in fuel economy is the result of taking the best parts of both the gasoline engine and the electric motor and using them in tandem. A vehicle powered only by an electric motor has a limited driving range, lengthy recharge time, and an inconsistent performance, depending on the strength remaining in the battery. While vehicles powered by an internal combustion engine are more flexible than electrics, these vehicles are set up to deliver much more power than is needed most of the time. A typical sedan, for example, has a gasoline engine that produces around 200 horsepower, but that capability is tapped only sporadically, such as when the driver needs to pass someone on the highway or when climbing a steep mountain grade. Some driving situations require about half the vehicle's horsepower, but many times only 20 to 30 hp is needed, such as to maintain cruising speed on the highway. As a result, the vast majority of the time, only a small fraction of the 200-hp engine is being used to actually power the car.

A hybrid vehicle uses a smaller engine with less horsepower and pairs it with an electric motor to deliver extra power when necessary. In addition to utilizing a gasoline engine and an electric motor more efficiently, hybrid vehicles also feature "regenerative braking" to further improve fuel economy. When the vehicle's brakes are applied or when it is coasting, the electric motor becomes a generator and captures the energy that would be lost as heat. The captured energy is transformed into electricity, which recharges the batteries, increasing the number of miles that can be traveled per gallon of gasoline. This is the reason that the city fuel economy is higher than highway fuel economy in hybrid vehicles. An added benefit is less wear on the brake pads, which means that they don't need to be replaced as often as conventional brakes.

Hybrid Technology Nearly A Century Old
While the first modern-day hybrid, the Honda Insight, was introduced in the United States in December 1999, it was not the first time a hybrid was seen in this country. The Woods Motor Vehicle Company of Chicago introduced its Dual Power model in 1916, promoting it in its sales brochure to the "man or woman who has owned either gas or electric cars or both and found them inadequate because of complications and limitations."

The Woods Dual Power had two "finger levers" on the steering wheel that operated each power source and a single pedal to accelerate and brake. Once the levers were set, power was sent from either the gas engine or electric motor through the propeller shaft to the rear axle. The gasoline engine and the electric motor were connected through the use of a magnetic clutch. As a result, the vehicle could be operated on electric power only, on gasoline only or on both simultaneously.

To start the car using the electric motor, the driver simply moved the electric finger lever, which connected the storage battery with the electric motor. Once the vehicle was started, the lever could be advanced to increase the speed of up to 20 mph. To travel at higher speeds, the driver engaged the gasoline lever, which connected the two power sources, allowing the gasoline engine and electric motor to run at the same time.

Through adjustment of the two finger levers, the battery could be discharged or recharged during driving at speeds of 10 to 30 mph. Recharging was accomplished with the gasoline engine being used to power the electric motor which, once fully juiced, acted as a generator. There was even a form of regenerative braking.

How Hybrids Work
The Woods Dual Power was perhaps a bit ahead of its time. When it was invented, the technology required to integrate the combustion engine and the electric motor seamlessly was nonexistent. The hybrid concept would have to wait over 80 years before it would be refined enough to once again go into production in passenger vehicles. (Hybrid technology has been used throughout the last century to power railroad locomotives and heavy-duty vehicles.)

Today's hybrids, however, still operate under much of the same principle as the Woods Dual Power. The hybrids on the market currently are prime examples of how modern computer technology can make the hybrid concept successful in volume production. To learn more, read "How a Hybrid Works."

Making a Difference 1 MPG At a Time
In all hybrid systems, the result is that the electric motor provides some of the power necessary to move the vehicle, allowing the use of a smaller combustion engine. The results are better gas mileage and fewer emissions.

"Improving fuel economy by 1 mile per gallon is much more important in a low fuel economy vehicle than in a high fuel economy vehicle, because the percentage of savings is actually much higher," said Jeff Alson, senior engineer at the EPA's National Vehicle and Fuel Emissions Laboratory. "Think of it this way, if a hypothetical vehicle only gets 1 mile per gallon of fuel to begin with, increasing it by 1 mile per gallon would double your fuel economy. On the other hand, if your vehicle gets 100 miles per gallon, increasing to 101 mpg would only improve your fuel economy by 1 percent."

These small improvements in fuel economy really do add up, even for the individual driver. For example, if you get about 16 miles per gallon on average in your midsize SUV and you drive 15,000 miles a year, you'll save $268 annually (based on the current national average price of $2.58 per gallon) if your fuel economy is improved by just 2 mpg.

Hybrids of the Future
As hybrid technology continues to evolve, variations on the gasoline-electric hybrid as we know it today are beginning to emerge. The National Vehicle and Fuel Emissions Laboratory at the EPA is currently developing the world's first full hydraulic hybrid urban delivery vehicle in partnership with UPS, Eaton and others. Hydraulic hybrids operate in essentially the same manner as the gasoline-electric hybrids currently on the market, but they use a hydraulic motor in place of the electric motor. "Instead of transforming electricity into mechanical energy, which makes the vehicle move, we use a hydraulic accumulator to store nitrogen gas and a hydrogen motor to highly compress the gas, which then creates energy used to power the vehicle," explained Jeff Alson, senior engineer at the EPA's National Vehicle and Fuel Emissions Laboratory.

Hydraulic hybrids are an intriguing direction for the auto industry because they are far less expensive than the current hybrid technology. The EPA's hydraulic hybrid is paired with a diesel engine, but the EPA's Alson says that the hydraulic hybrid technology could be used with virtually any engine configuration. Instead of using a conventional transmission and transfer case, the EPA's hybrid uses a hydraulic drivetrain, which operates "essentially like a continuously variable transmission," he said. By eliminating these two components, some of the cost of the hybrid technology is negated.

Like other hybrids, the hydraulic hybrid will have lower emissions and lower brake maintenance costs. In addition, the EPA projects a 30- to 40-percent improvement in combined fuel economy with the greatest improvement being in city driving and, because it uses a diesel engine instead of gasoline, much better acceleration. While vehicles that are used primarily around town in many short stops, such as delivery vehicles, will experience the greatest benefits from this technology, it is possible that hydraulic hybrid technology could be applied to passenger vehicles one day.

Until then, the current approach to hybrid vehicles is continuing to catch on. J.D. Power-LMC Forecasting predicts that there will be 38 hybrids (17 cars and 21 pickups) on sale by 2011. As more vehicles are introduced, competition will increase, most likely leading to a greater vehicle variety and lower overall prices. Sounds like a surefire way to make the hybrid market even hotter.