Vehicle powertrains explained

Choosing a powertrain is an important element in your quest for a new car. The 3 basic types of powertrain are:

1. Vehicles powered by internal combustion engines (ICEs) that burn gasoline, diesel fuel, or flexible fuel. This is the most common type of powertrain by far, but by no means necessarily the best.

2. Vehicles with ICEs and electric motors that are powered by gasoline and electricity—that is, hybrids and plug-in hybrids (PHEVs). Both vehicle types are enjoying a resurgence in popularity, and for good reason: They’re fuel-efficient, reliable vehicles, with few downsides.

3. Vehicles with 1 or more electric motors (electric vehicles, or EVs) or hydrogen fuel cell vehicles, both of which are powered by electricity. Many automotive pundits and automakers alike believe that EVs are the future of personal transportation.

Most car buyers in the U.S. are interested in buying vehicles with an ICE that burns gasoline, which make up 90% of the passenger vehicles on the road today. According to a survey of 4,000 readers of Car and Driver and Good Housekeeping, 93% said their current cars were powered by gasoline, and some 63% said they’d prefer that their next car have a gasoline engine. By contrast, 24% said they’d prefer a hybrid or plug-in hybrid (gasoline and electricity), and just 10% said they wanted an EV.

The 2021 Global Automotive Consumer Study by Deloitte found pretty much the same thing. When presented with a choice of gasoline-powered, hybrid, or electric vehicles, 74% of Americans— higher than in any other country—said they wanted their next vehicle to be a traditional car, powered by a gasoline or diesel engine.

Gasoline-powered engines are more inefficient, and they’re a major contributor to greenhouse gas emissions, which cause climate change. So, given their negatives, what explains gasoline-powered engines’ popularity?

People prefer gasoline-powered vehicles for 2 main reasons: convenience and familiarity. Vehicles with ICEs can be refueled quickly at more than 150,000 filling stations. They can easily be serviced at nearly 17,000 new-car dealerships in the U.S. Their owners can buy parts and accessories for them at dealerships and at thousands of auto-parts stores across the country.

Societal forces, too, conspire against the adoption of alternative powertrains. Automakers, gas stations, car dealerships, auto parts stores, and the oil industry itself represent powerful vested interests with a considerable stake in maintaining the status quo.

Then there’s familiarity: Gasoline-powered cars and light trucks are known quantities—reliable, proven technology. They do their job—”if it ain’t broke, don’t fix it,” as the saying goes—so most people keep buying and driving them.

By comparison, hybrid, plug-in hybrid, and electric vehicles—even though their technologies have been around for decades—are question marks for most car buyers. And they often cost more to buy than gasoline-powered cars and trucks. In the case of EVs, they take longer to refuel, and charging stations can be few and far between.

Increasingly stringent corporate average fuel economy (CAFE) and emission standards require automakers to keep improving the efficiency of gasoline-powered vehicles. They do this by continually improving vehicle drivetrains—making use of small-displacement turbocharged and variable-compression engines, gasoline direct injection, CVT transmissions, stop-start technology, and electric steering, for example. Other techniques include improving vehicle aerodynamics (such as active grille shutters) and using lightweight materials such as aluminum and carbon fiber in place of steel.

Unlike Europeans, Americans have never shown much interest in diesel cars, especially after the Volkswagen “dieselgate” emissions scandal of 2015, which has aptly been described as having killed the diesel car market overnight.

In 2022, no diesel cars, foreign or domestic, are for sale in the U.S. Several marques, including Jaguar, BMW, Mercedes-Benz, and Volkswagen, dropped diesels from their U.S. car lineups years ago. SUVs and pickups are another story, however. Diesel engines don’t dominate those segments, but they are featured prominently.

Current SUV models with a diesel option include the Chevrolet Tahoe and Suburban and the similar Cadillac Escalade/Escalade ESV and GMC Yukon/Yukon XL; the Jeep Gladiator and Wrangler; and the Land Rover Discovery and Range Rover.

Pickup trucks that can be outfitted with a diesel engine include the Chevy Colorado and its corporate twin, the GMC Canyon; the Chevy Silverado 1500, Silverado HD, and their twins, the GMC Sierra 1500 and Sierra HD; and the Ram 1500/2500/3500. The Ford F-Series and Nissan Titan recently dropped their diesel options due, in part, to low demand. Some cargo vans, such as the Chevrolet Express/GMC Savana and the Mercedes-Benz Sprinter van, also can be equipped with a diesel engine.

Diesels are prized for their high fuel economy, ample torque, and lower levels of CO₂ emissions, which for many consumers offset diesels’ negatives: a higher purchase price for both vehicles and fuel, greater oxides of nitrogen and particulate emissions, and louder engine noise.

In 2021, sales of diesel vehicles increased by a modest 5.1% over 2020: 176,538 diesel vehicles sold in 2021 compared with 167,898 in 2020. Best-selling diesel vehicles included the Mercedes- Benz Sprinter Diesel (42,367, up 10.0%), Chevrolet Silverado Diesel (31,186, up 6.1%), and Ram 1500 Diesel (27,171, up 10.6%). General Motors is the leader in diesel sales, with 38.5% of the market; Mercedes-Benz is second at 24.0%. Total U.S. diesel sales in 2021 amounted to about 1.2% of all vehicles sold.

Ethanol is a biofuel—a clear, colorless alcohol—that can be made from renewable sources such as corn, sugar beets, sugarcane, and other forms of biomass. Most ethanol in the United States is made from corn; about one-third of the U.S. corn crop is used for ethanol. Nearly all gasoline sold in the U.S. contains at least 10% ethanol.

E85, or flex fuel, is a gasoline-ethanol blend containing 51% to 83% ethanol. A flexible-fuel vehicle, a.k.a. a flex-fuel vehicle or FFV, is a vehicle with an engine designed to burn either standard gasoline or E85.

Up to 10% of passenger vehicles on U.S. roads are able to run on E85. However, owners of flex-fuel vehicles might not be aware that they’re driving an FFV. Flexible-fuel vehicles are distinguished only by a small badge or label, usually on the rear of the vehicle, or by a yellow gas cap, fuel-filler ring, or label inside the fuel flap. Go to fueleconomy.gov to learn more about FFV models.

Ethanol has pros and cons as an automotive fuel. It has a higher octane than gasoline, so it produces more power, and it burns more cleanly, producing just 20% to 25% of the greenhouse gas emissions of gasoline. However, E85 also contains about one-third less energy than gasoline, which results in a 15% to 27% drop in fuel efficiency. On balance, running a car or light truck on E85 costs more than running it on straight gasoline.

E85 is available at about 4,400 service stations in the U.S., mainly in the Midwest, on the East Coast south of New Hampshire, and in much of Florida. It’s less available in New England and regions west of the Mississippi River, with the exception of some large cities, such as Denver, Los Angeles, San Diego, and San Francisco.

To find out where E85 is available in your state, go to the U.S. Department of Energy (DOE) Alternative Fuels Data Center’s station locater.

As the name suggests, a hybrid is any car or light truck with more than 1 powertrain: In the United States, that means a gasoline engine, 1 or more electric motors, a battery pack, and a controller that determines whether the gas engine, the electric motor, or both, will propel the vehicle.

Mass-produced hybrids have been in existence for a quarter of a century—the first was the 1997 Toyota Prius—and hybrid technology has proven to be both effective and reliable. Hybrids don’t require any special maintenance, they drive like conventional cars, and their hybrid components (including the costly battery pack) have long warranties. Hybrids that focus on fuel efficiency often achieve mpg numbers in the high 40s and low 50s.

Nearly 30 hybrid models are currently for sale in the U.S., spanning all price ranges and body styles, from a Honda Insight sedan (52 mpg combined, base price: $25,210) to a Toyota RAV4 Hybrid XSE SUV (40 mpg combined, base price: $34,850) to a Ford F-150 XL HEV pickup (24 mpg combined, base price: $43,835). Some hybrids are bargains: For 2022, 8 hybrids with 50-plus mpg fuel-economy numbers have base prices under $30,000: the Honda Accord Hybrid and Insight; the Hyundai Elantra Hybrid, Ioniq Hybrid, and Sonata Hybrid; and the Toyota Camry Hybrid, Corolla Hybrid, and Prius.

Hybrids typically cost more than their nonhybrid counterparts, but because, on average, they increase fuel economy by about 30%, you can often make up the price difference in fuel savings. To find out if the numbers work for you, go to “Can a Hybrid Save Me Money?” on the home page of the EPA website.

Automakers are divided on the future of hybrids in their lineups. Ford, Hyundai, Kia, Lexus, and Toyota have recently expanded their hybrid offerings (the redesigned Toyota Sienna hybrid minivan, Ford Explorer Hybrid, and Kia Sportage Hybrid are examples). But Volkswagen and General Motors are now focusing on EVs, which many automakers see as the future of personal transportation.

Total hybrid sales for 2021 were 801,895, versus 457,435 in 2020, an increase of 75.3%. Toyota’s RAV4 Hybrid (120,983), Sienna (107,130) and Highlander Hybrid (65,167) took the top 3 spots in 2021. Hybrid sales in 2021 represented 5.4% of total U.S. vehicle sales, up from 3.2% in 2020. Toyota ruled the hybrid segment with 65.9% of sales in 2021.

Fourteen hybrids are reviewed in the 2022 AAA Car Guide. Visit fueleconomy.gov for a complete list of hybrids currently available for sale.

A plug-in hybrid (a.k.a. plug-in hybrid electric vehicle or PHEV) is a hybrid with a bigger battery pack and a port to charge it, either at home or at a public charging station. PHEVs have been in existence for a little more than a decade: The first, the discontinued Chevy Volt, went on sale in late 2010.

The difference between PHEVs and hybrids is that PHEVs can drive on electricity alone for between 20 and 50 miles, depending on a vehicle’s range, until their battery pack is depleted. That saves PHEV owners money because electricity is cheaper to run on than gasoline.

When a PHEV’s battery pack is depleted, the gas engine kicks in and motorists continue driving in hybrid mode until they recharge the battery pack or stop to buy gas. Fully charging a PHEV’s battery can take 8 to 10 hours at 120 volts (Level 1 charging) or about half that time at 240 volts (Level 2).

Because a PHEV runs on electricity alone part of the time, it uses 30% to 60% less gasoline than a conventional vehicle. Ideally, PHEV owners can drive most or all of their daily mileage using just electricity, stopping only infrequently to fill the gas tank.

A PHEV’s fuel economy is estimated 2 ways: in MPGe (miles per gallon equivalent) when running on electricity alone and in mpg otherwise. MPGe is defined as the number of miles a vehicle can travel on the amount of electricity with the same energy content as a gallon of gas.

PHEVs cost more than equivalent gasoline-powered vehicles. But their higher purchase price often can be offset by federal and state tax incentives. Go to the DOE website and the Alternative Fuels Data Center and type “PHEV tax credits” into the search box. In some states, PHEVs can use carpool lanes with only the driver aboard.

If you’re interested in purchasing a PHEV, the My Plug-in Hybrid Calculator tab at fueleconomy.gov will help you estimate your annual gas and electricity costs based on your driving habits.

Forty plug-in hybrids are available for sale in 2022—including such exotics as the Bentley Bentayga and Ferrari SF90 Stradale. Honda stopped producing its Clarity Plug-in Hybrid sedan in August 2021 because of declining sales. Go to fueleconomy.gov for a complete list of plug-ins. The 2022 AAA Car Guide has reviews of 7 PHEVs.

After taking a hit in the past 2 years, PHEVs rebounded in jaw-dropping fashion, from 72,696 PHEVs sold in 2020 to 176,298 PHEVs in 2021, a whopping 142.5% increase. The 3 top-selling PHEVs were the Jeep Wrangler 4xe (33,500), the Toyota RAV4 Prime (27,707), and the Toyota Prius Prime (25,042). Plug-in hybrid sales amounted to 1.2% of total U.S. vehicle sales in 2021, up from 0.5%. Toyota (29.9%) and Stellantis (22.2%) led the market in PHEV sales.

Electric vehicles (EVs), sometimes known as battery-electric vehicles (BEVs), have 1 or more electric motors, a 1-speed transmission, and a large, rechargeable battery pack. More than 2 dozen EVs are now for sale in the U.S., and 100 more are expected in the next 5 years—everything from sports cars to pickups.

Although they currently make up only about 2% of passenger vehicles, EVs are no longer considered a niche market. Over the next 5 years, EV sales are projected to surpass the 1.4 million sold since 2010, according to the online Charged Electric Vehicles Magazine.

EVs have been the big news in the automotive world for several years and still are—arguably more than ever. Their appeal expands as automakers increase their range, power, utility, and style. Nearly every major automaker is now producing EVs or will in the near future—sometimes on an ambitious scale.

EVs are available in a variety of body styles, from sporty subcompacts (Mini Cooper SE) to large luxury sedans (Porsche Taycan) to midsize SUVs (Ford Mustang Mach-E). Pickups have recently joined the mix, too. EV startup Rivian delivered an R1T, the industry’s first EV pickup, this past fall. The Ford F-150 Lightning EV pickup is expected in spring 2022; based on high interest, Ford plans to spend $850 million to double the Lightning’s production goals.

EVs are fun to drive, with quick acceleration and a quiet ride. They’re structurally less complicated, with about one-third of the parts used in other types of vehicles, so they require less maintenance. Most EVs also get extremely good fuel economy (expressed in MPGe, like plug-in hybrids) because electric motors are highly efficient.

The (typically) lower cost of electricity makes EVs cheaper to run, and in many states, EVs can use carpool lanes with only the driver aboard. To find out how much it costs to run an EV in your state, access the DOE’s eGallon calculator.

EVs produce no emissions at their (nonexistent) tailpipes. Including the energy used to manufacture them, and regardless of the electricity source used to power them, they produce fewer global-warming emissions than any other type of vehicle, according to the Union of Concerned Scientists.

Because car buyers are unfamiliar with EVs, many have concerns about them—real or imagined—which has slowed EV adoption. A 2020 AAA survey revealed that the top 3 misgivings were range anxiety (57%), unsuitability for long-distance travel (53%), and lack of places to charge an EV (52%).

The solution appears to be education and actual experience with EVs, much of which dealers can provide. Once drivers purchased an EV, their concerns eased considerably: 77% of those who worried about lack of range became less concerned or not at all concerned; 54% became unconcerned or less concerned about an EV’s suitability for long-distance travel; and 70% felt unconcerned or less concerned about a lack of places to charge their EV.

For most EV owners, keeping their vehicles charged turns out not to be a real issue—it just takes planning, as does using their EV for long-distance travel. More than 80% of EV owners charge their vehicles at home on 240-volt (Level 2) chargers, which provides 10 to 24 miles of range per hour of charging. Home charging systems cost about $1,000 to $1,200 to purchase and install; local or state incentives to reduce the cost may be available.

The number of public charging stations continues to expand, including Tesla’s Supercharger network and those at shopping centers and workplaces. In January 2022, there were about 50,000 EV charging stations nationwide, up from 29,000 in 2020, with 129,000 charging ports. Even better, more than 88,000 ports were Level 2, and more than 20,000 provided DC fast charging, which typically dispenses an 80% charge in about 30 minutes. Finding a charging station is easy—all EVs have software programs that display nearby charging stations on their touch screens.

Owning an EV is inconvenient for apartment dwellers or anyone without a garage, although more residential and commercial buildings are installing chargers as a service to their residents or employees.

Another concern is that EVs are expensive. That’s true for some brands, but several EVs—the Nissan Leaf, Mini Cooper SE, and Chevy Bolt, for example—start in the high 20s and low 30s.

Many qualify for federal and state tax credits of up to $10,000, although those benefits have run out for some of the most popular EVs—all Teslas and the Bolt, for instance. Prices may drop further as the cost of battery packs—the most expensive component—come down. Bloomberg predicts that by 2023, their cost will drop to $100 per kilowatt-hour (kWh), at which point EVs could reach price parity with conventional vehicles.

For the latest information on federal tax credits, go to the DOE website and the Alternative Fuels Data Center and type “EV tax credits” into the search box to find out about federal and state tax incentives for any EV you are considering. Additionally, fueleconomy.gov lists more than 2 dozen currently available EVs, with information on their manufacturer’s suggested retail prices (MSRPs), drivetrains, estimated MPGe, annual fuel costs, and more. 

In 2021, EV sales increased to 476,679 vehicles, an 81.5% increase over 2020 sales (262,698). Tesla again dominated the field, with 71.7% of EV sales. Top sellers included the Tesla Model Y (188,600 up 140.8%), Model 3 (estimated 140,450, up 40.2%), and the Ford Mustang Mach-E (27,140, new this year). EV sales represented 3.3% of total U.S. vehicle sales in 2021. Six EVs are reviewed in the 2022 AAA Car Guide.

Hydrogen fuel cell vehicles are EVs that run on their own electricity, producing it onboard by a chemical process in which hydrogen, stored in tanks, reacts with oxygen from the air. Their only emissions are heat and water.

Fuel cell vehicles are expensive, and only 2 models are being produced for sale. Both have been on the market for several years and are in their second generation—the Toyota Mirai sedan ($49,500) and the Hyundai Nexo SUV ($58,935). Each is available in 2 trim levels. Honda pulled the plug on its Clarity Fuel Cell sedan in August 2021.

The California Fuel Cell Partnership estimates that there are about 11,000 fuel cell vehicles currently on the road, mostly in California, because that’s about the only place they’re sold or leased, and it’s where virtually all the hydrogen refueling stations are.

Toyota, Hyundai, and government agencies offer significant incentives to go hydrogen, among them free fuel for up to 6 years or $15,000, car-pool-lane access with only the driver aboard, a federal tax credit of up to $8,000, a California rebate of up to $4,500, complimentary servicing, price discounting, and 0% financing.

In January 2022, there were 49 operating public hydrogen refueling stations in California; 10 under construction; 27 in the permitting phase; and 16 proposed. Most are located in the Sacramento, greater Los Angeles, and San Francisco Bay regions. A California Air Resources Board (CARB) report projects that 100 retail hydrogen stations will be operating in California by the end of 2023, and by 2026 the state will have more than 175 operating stations—enough to support 250,000 fuel cell vehicles.

The problem, as always, is that projections often don’t match reality. To this point, vehicle sales and station openings have consistently failed to match expectations. And hydrogen advocates must face formidable obstacles: Hydrogen fuel stations cost up to $1 million each, and delays in the construction process are chronic. Furthermore, there are only 10 Toyota dealers that sell and service Mirais in the state and only 5 Hyundai dealers that handle Nexos.

And, because of the limited number of fueling stations, fuel cell vehicle owners can forget about extensive travel north of Sacramento, let alone out of state. Compare that to what’s available to EV owners—nearly 40,000 public and shared private vehicle-charging plugs throughout the state.

In 2021, 3,341 FCVs were sold, a 257% increase compared with the 937 sold in 2020. That number included 2,629 Toyota Mirais (up 427%), 430 Hyundai Nexos (up 107%), and 282 Honda Clarity Fuel Cell vehicles (up 2%). Fuel cell sales represented 0.02% of total U.S. vehicle sales in 2020. Toyota’s share of the market was 79%.

Excerpted and adapted from the AAA Car Guide, which is also available in hard copy at AAA branches.