They say new technologies such as improved turbochargers, direct fuel injection, advanced transmissions with six speeds and electric-power-assisted steering are producing four-cylinder vehicles with the type of zip Americans demand in their autos.
Later this year, Ford will sell a version of its new-generation Explorer SUV with the automaker's two-liter, four-cylinder "EcoBoost" engine.
It is the first time Ford has ever offered the iconic Explorer with a four-cylinder engine. The previous smallest engine was a 4.0-liter V-6 that produced 210 horsepower. But this new engine will be almost 20% stronger and will get about 26% better fuel economy, putting it in the high-20-mpg range for highway driving.
Hyundai has almost abandoned anything bigger than a four-cylinder, which will account for nearly 90% of its U.S. sales this year.
"We are not counting cylinders. What we are doing is trying to be the world's most fuel-efficient automaker," said John Krafcik, chief executive of Hyundai Motor America. "A well-optimized four-cylinder engine happens to be the best way to do it, and that is why we are employing it in larger cars than we would have in the past."