A leading automotive tech expert provides the basics about how hybrid cars work and tells how to choose the best hybrid vehicle for your driving needs.
More than a dozen years after the first hybrid cars arrived in the United States, shoppers now can choose among 33 different gasoline-electric hybrid vehicles from every major automaker, with more to come. The best of these high-mpg cars offer a compelling combination of features: high fuel efficiency, long-term affordability and long driving range. The technology of these fuel-efficient cars is proven and here to stay, with more than 2.1 million hybrids on U.S. roads. Though that represents only about 1 percent of all our vehicles, it’s the first “green” alternative that has reached this level of adoption.
Hybrids have become so common — in California, the Toyota Prius outsells the longtime best-selling gasoline-powered Camry family sedan — it’s easy to forget the drastic measures previous generations took to get phenomenal gas mileage.
For example, there was the Arkansas man in the late 1970s who ripped out the gas engine of his Opel GT coupe and replaced it with an electric motor, 5-horsepower lawn mower engine and four 12-volt batteries. When he was finished, David Arthurs had a homemade hybrid car that could go 75 miles on just 1 gallon of gasoline. He published his blueprints in the July/August 1979 issue of MOTHER EARTH NEWS. (Go to Electric Car Conversion: The Amazing 75-MPG Hybrid Car to read the original article.)
For the adventurous DIY crowd, the mileage was great, but reliability and durability were another matter. The level of sophistication and computerization of today’s hybrids is a far cry from Arthurs’ lawn mower hybrid, but the basic idea of a hybrid hasn’t changed. In fact, the inner workings of the first known hybrid — produced in 1898 by then unknown 23-year-old engineer Ferdinand Porsche — were similar to today’s systems. Instead of solely relying on a gasoline internal-combustion engine to power the wheels, an electric motor and batteries are also called into service — especially during moments when either pure electricity or a gasoline-electric combo can maximize efficiency.
The availability of the electric motor for propulsion enables the hybrid to burn less gasoline. Today’s hybrids — the ones that don’t plug in — use sophisticated onboard computers to decide which source of power to use when, and how much and when to blend the two.
Toyota’s hybrids, the Ford Fusion and several others on the market are considered full hybrids, meaning that the vehicles can drive at low speeds solely using electric power. Most full hybrid systems have two electric motors — one to supply traction to the wheels, and the other to turn the gas engine on and off smoothly. On the other hand, a “mild” hybrid — most notably the single-motor system from Honda — can move from a standstill only if the internal-combustion engine is engaged. It uses the electric motor primarily to assist the gas engine to improve efficiency. Some of the newer hybrid systems — from Hyundai and Volkswagen, for example — have only one motor, but use a clutch to automatically disengage the gas engine so only the electric motor moves the wheels at low speeds.
All hybrids, as well as pure electric cars, have regenerative braking, which reclaims energy that would normally be lost. Instead of discarding this energy as heat from the brakes, regenerative braking turns the electric motor into a generator that recharges the batteries. All models shut down the gasoline engine when stopped — no more wasting gas while idling. The result is vehicles that use as little gasoline as possible.
Here’s a distinct advantage of hybrids: By having two sources to draw from when you need maximum power — as when entering a highway on-ramp — the gas engine and electric motor team up to provide the necessary oomph. Thus, a smaller, more efficient gas engine is just fine for the 90 percent or more of the time when you’re not pushing performance to the limit (see the Image Gallery for a chart on how the gas engine, batteries and electric motor work together to power a hybrid car).
These days, when you say “hybrid,” most people think of one model: the Toyota Prius. In fact, Prius has outsold all other hybrids combined, completely dominating the hybrid scene ever since the second-generation model was introduced in 2003. Toyota isn’t going to cede its leadership in hybrids anytime soon — especially with the recent introduction of an entire line of Prius models, from the original hatchback model to a plug-in version of the original, as well as the Prius V station wagon and a Prius C compact.
Despite the hegemony of the Prius thus far, the next few years will bring much greater diversification in hybrid technology. The flavor of hybrid used in the Prius will give way to all kinds of varieties: full and mild hybrids; hybrids with one motor and those with two; hybrids that plug into the wall and, mostly, those that don’t. The mild form of hybridization known as stop-start or auto-stop — strictly used to prevent your car from wasting gas while idling — is expected to become ubiquitous in the United States in coming decades, an innovation already on the rise in Europe.
Among conventional hybrids, the Toyota Prius hatchback continues to be the mpg king, with a combined city/highway EPA rating of 50 mpg. The new $19,700 compact Prius C, released in spring 2012, also has a combined rating of 50 mpg and the highest city rating (53 mpg) for any car without a plug. On the next tier of the ladder, only four vehicles, all hybrids, currently carry a combined rating above 40 mpg: the Honda Civic Hybrid, Honda Insight, Lexus CT 200h and Toyota Camry Hybrid. Some car companies are quick to advertise their small, efficient vehicles as “40-mpg cars,” but don’t be fooled: Those are strictly highway numbers, and their city mileage numbers are usually in the low 30s.
Hybrids have long been thought of as the corrective shoes of the automotive world — necessary but not exactly stylish or exhilarating. In fact, if maximum efficiency is your goal, the investment in a hybrid is best realized by driving with a slow and steady foot. An entire automotive subculture focused on “hypermiling” developed with the introduction of hybrids, providing minor tips to major tricks to help drivers eke out unusually high mpg.
If and when a hybrid driver dared to apply foot to accelerator with any force, many of the first- and second-generation hybrids — which use a continuously variable transmission (CVT) — produced a delayed response commonly called the “rubber band effect.” In other words, stepping on the gas was like pulling back a rubber band and waiting a beat or two for the genies under the hood to let go.
Part of the technology’s growing pains meant that many early hybrids were a little rocky in managing the switch between gas and electric. Yes, the engine turned on and off at the right times, but not without a slightly disconcerting rumble and shake. From my experience, the Toyota Prius — even in its current generation — still has this problem, although the newest Camry Hybrid shows that Toyota is making advances. While Ford uses a hybrid system quite similar to Toyota’s, engineers working for the Blue Oval got an early jump on producing smooth transitions. That’s evidenced by the refinement of the Ford Fusion Hybrid. The vehicle took all kinds of honors during its first years, including the Hermance Award given by a jury of automotive engineering experts who hailed the quality of its powertrain. The Fusion Hybrid showed that, with relentless levels of calibration, hybrids can be made so you simply can’t distinguish whether you’re driving on gas or electric.
The process of mainstreaming hybrids took another step forward with the introduction of the Hyundai Sonata Hybrid (and its cousin, the Kia Optima Hybrid). A gorgeous mid-size sedan with winning style, the Sonata Hybrid uses a six-speed automatic transmission instead of a CVT. There’s no rubber band effect; the car delivers decent power from the first gear, and provides the familiar sound and vibration everyday drivers expect from an automatic transmission. Compared with the Prius, the Hyundai Sonata Hybrid responds more like other best-in-class cars on the road. Unfortunately, it doesn’t match the fuel efficiency of the Prius, with a combined rating of 37 mpg, compared with 50 mpg for the Prius. A more apt comparison would be the Camry Hybrid, which sells for almost an identical price as the gasoline-electric Sonata and offers 41 mpg. The similarly sized 2013 Ford Fusion Hybrid, due in fall 2012, is expected to match the Sonata and Camry hybrids in terms of refinement and beat them on mileage.
Hyundai’s innovation hasn’t yet revolutionized the price and efficiency of hybrids. Some industry observers, however, see the technology the Korean company uses as a sea change of cost reduction. The additional cost of a hybrid compared with a gasoline-only car is what’s holding back even faster growth of the market. In 2011, when average gas prices broke previous records and the recession deepened, hybrids represented less than 3 percent of new car sales. Hyundai’s hybrids, like the next wave of hybrids from Volkswagen, Infiniti and others, will use a single motor, two clutches and a standard transmission rather than Toyota’s two-motor CVT strategy.
“It’s the next evolution of hybrids,” says John DeCicco, a University of Michigan professor and the founder of Auto Eco Rating. “What you have with this next round of systems is a lower-cost solution to providing the efficiency benefit comparable to a two-motor power-split system. That’s significant for public policy because it makes mandatory higher Corporate Average Fuel Economy (CAFE) levels less costly to achieve.”
It will take five to seven years before Hyundai, Volkswagen and others using the single-motor approach catch up with Toyota, says John German, senior fellow for the International Council on Clean Transportation. “Toyota is so much further down the learning curve, they’re operating at such higher volumes,” he says. Yet, by 2030, German thinks, lower-cost hybrid systems will dominate the mass market. “They’ll start becoming standard on vehicles by 2020.”
In 2012, we have reached the point where consumers can find a hybrid with nearly any set of desired attributes. To date, the minivan remains the one gap in the hybrid market. (For more on minivans see Ask Our Experts: Hybrid Minivan In the Near Future.)
Roland Hwang, clean vehicle specialist at the Natural Resources Defense Council, returned from the 2012 Detroit Auto Show certain that hybrids have come in from the fringes. “The big news was that hybrids are not big news,” he says. “They have become just another engine option.” Car shoppers will buy hybrids versus less expensive conventional engine options for reasons that go beyond the pocketbook, Hwang says. They’ll choose this highly efficient technology because they care about driving the most fuel-efficient cars to help get the United States off oil, to clean up the environment, or just to avoid the gas pump.
See the Image Gallery and then click “Next” to view “Berman’s Top Hybrid Cars” while reading about each hybrid vehicle.
1. Toyota Prius: The 50-mpg Prius outsells all other hybrids combined. In 2012, this quintessential hybrid will have wagon, compact and plug-in hatchback versions.
2. Hyundai Sonata Hybrid: The gasoline-electric Sonata is a great-looking midsize sedan that achieves 37 mpg combined and provides the automatic transmission “feel” most U.S. motorists find familiar.
3. Ford Fusion Hybrid: When the new 2013 model hits this fall, the Fusion will sport an updated look. The new hybrid version is expected to increase the vehicle’s mpg to about 47 in the city, 43 on the highway.
4. Lexus RX 450h: With Ford shelving its Escape Hybrid (for now), the 30 mpg Lexus RX 450h becomes the most efficient SUV on the market. The RX hybrid has been the best-selling luxury hybrid SUV for the past three years.
5. Honda CR-Z: Rated at 34 mpg with a six-speed manual or 37 mpg with an automatic, the two-seat CR-Z was the third best-selling hybrid in 2011. Even if not a speed demon, the sporty-looking CR-Z is a blast to drive, especially the manual version.
Auto Eco Rating
A new blog from one of the top automotive environmental analysts, this site offers in-depth “well-to-wheels” ratings and perspectives for the green car cognoscenti.
This official site from the Department of Energy and the Environmental Protection Agency provides basic fuel economy stats, calculators and mpg side-by-side comparisons for all cars and trucks.
For more than a decade, the American Council for an Energy-Efficient Economy has produced comprehensive environmental rankings of vehicles. Highlights are free; detailed data requires a small fee.
Kelley Blue Book
When you’re getting close to making a purchase, this website is the ultimate source for determining what you should pay and how much your current car is worth.
The first independent, dedicated shopping site for electric cars and plug-in hybrids. The site also has a vibrant community of plug-in car drivers.
U.S. News Best Cars
This media company, known for its vehicle rankings, provides some of the best information for all — not just green — cars and trucks. Its well-organized reviews pulls highlights from across the Internet.
Bradley Berman writes about electric and hybrid cars for The New York Times, Yahoo! Autos and Reuters. He was the founder of HybridCars.com and PluginCars.com and consults on green cars for the Natural Resources Defense Council and eBay.
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