The differences between gasoline and diesel engines lie not only in their fuels, but in how those fuels are ignited. Gasoline engines use spark plugs, while diesels simply use compression. But it is possible to ignite gasoline in an internal-combustion engine with compression, as in a diesel. DON'T MISS: Mazda diesel to arrive fall 2017 in new... Mazda to launch homogeneous-charge compression engine next year
The differences between gasoline and diesel engines lie not only in their fuels, but in how those fuels are ignited. Gasoline engines use spark plugs, while diesels simply use compression. But it is possible to ignite gasoline in an internal-combustion engine with compression, as in a diesel. DON'T MISS: Mazda diesel to arrive fall 2017 in new... 
Since Ford launched its line of downsized EcoBoost engines in 2009, the "eco" part of that name has often required an asterisk. That's because some owners have found that real-world fuel economy results don't always live up to the vehicles' official EPA ratings. The phrase "you can have Eco, or you can have Boost, but you can't have both at the... 
For nearly a decade, the average fuel economy of new cars sold in the U.S. steadily increased—but that moment has stalled in recent years. Low gas prices and increased consumer interest in SUVs has caused new-car average fuel economy to plateau and, in the case of 2016's figures, decline slightly. The average fuel economy of new cars sold in... ![Elio Motors 84 mpg 3-wheeler [Image: Elio Motors]](http://images.hgmsites.net/tmb/elio-motors-84-mpg-3-wheeler-image-elio-motors_100477636_t.gif)
Three-wheeled vehicles have never been remotely popular in North America, but some new makers of these unusual vehicles are hoping for a resurgence of interest. Falling into a gray area between cars and motorcycles, production-ready electric and gasoline 3-wheeled vehicles have been wheeled out by several companies promising deliveries in the near... 
The Mitsubishi Mirage is the underdog of small cars: slow, loud, and archaic, but scrappy. And it's been a much bigger sales success than Mitsubishi expected, given the small numbers of minicars and subcompacts sold in the U.S. these days. For 2017, Mitsubishi added a four-door sedan model dubbed G4 to the existing five-door hatchback, and gave... 
When it comes to regulations governing the auto industry, the Obama administration does not plan to go gentle into that good night. The outgoing administration has pushed through a number of new regulations, some related to fuel efficiency, before President-elect Donald Trump takes office next month. The move is likely a hedge against the incoming... 
It's well known by now that the European Union testing protocol for fuel economy is much less rigorous than the U.S. Environmental Protection Agency (EPA) standards. Both protocols are based around laboratory testing rather than real-world evaluation, but EU figures have gained a reputation for being much more optimistic than what drivers can... 
While diesel vehicles have received a black eye in the form of the Volkswagen emissions scandal, they often still deliver better fuel economy than comparable gasoline models. But does a lower volume of fuel consumed necessarily translate into lower ownership costs? Various cars, SUVs, and pickup trucks sold in the U.S. are offered with... 
The 2017 Toyota Prius Prime turned out to be a better plug-in hybrid than we had expected when we drove it around sunny Ojai, California, on the press launch in October. It's a viable competitor to the second-generation Chevrolet Volt plug-in hybrid, though the Volt has an EPA-rated 53 miles of electric range to the Prime's 25 miles. Now we've had... 
Plug-in electric cars are slowly becoming more common, but internal-combustion engines will remain a significant presence on the world's roads for decades to come yet. That means automakers will continue trying to squeeze ever-greater efficiency out of these engines, making them more complex in the process. This will almost certainly include a... 
Car buyers remain aware that the real-world fuel economy of new vehicles may not match the ratings on their window stickers. The year-old Volkswagen diesel scandal has also shown the vulnerability of laboratory emissions tests to deliberate cheating by manufacturers. But the news isn't entirely bad. DON'T MISS: EPA reports show automakers meeting... 
Are you driving a car or a truck? The answer may be harder to determine than you think. U.S. safety and emissions regulations generally split cars and trucks into two categories, but the line between those two vehicle types has become blurred in recent years. That's thanks to the car-based crossover utility vehicle, which now represents one of the... 
The Volkswagen diesel scandal convinced European regulators to switch from laboratory emissions testing to tests that involve actual, on-road driving. This could prevent automakers from deploying "defeat device" software like the kind used by VW on laboratory tests, as well as produce results that more closely align with what consumers can expect... 
The Ford Mustang isn't usually the first vehicle that comes to mind when thinking about fuel-efficient cars. But a new Mustang recently won the title of most-improved fuel economy in a U.K. gas-mileage marathon. It wasn't a Mustang EcoBoost, the 2.3-liter turbocharged 4-cylinder model introduced to provide at least somewhat more-efficient... 
While it plans to launch 10 new electric cars by 2025, Mercedes-Benz is far from done trying to improve the efficiency of internal-combustion engines. The German luxury automaker is giving its lineup of engines a major overhaul, in fact. It plans to introduce a new family of 4-, 6-, and 8-cylinder engines, with the new engines starting to arrive... 
Stricter global emissions standards have led many automakers to downsize engines, but that trend may be about to reverse itself. Cutting displacement is a relatively straightforward way to improve fuel economy. But as regulators move toward adoption of more realistic testing procedures in the wake of the Volkswagen diesel scandal, automakers may... 
The 2017 Ford F-150 full-size pickup truck get sa slight fuel-economy bump this year, via the addition of a new 10-speed automatic transmission and an updated 3.5-liter twin-turbocharged EcoBoost V-6 engine. Equipped with this powertrain, the 2017 F-150 is rated at 21 mpg combined (18 city, 25 highway) with rear-wheel drive, and 20 mpg combined...