New class of engine reshaping auto industry

The most exciting, technically intriguing engines I’ve tested in the past six months weren’t throbbing V-8s, exotic V-12s, trendy electric-gasoline hybrids or post-modernist hip European diesels.

My heart — and my eager right foot — belongs to the 2.0-liter four-cylinder engine. Engines that size were long dismissed as weaklings fit only for little economy cars. Americans weren’t inclined to take an engine seriously if the total displacement of its cylinders was the same size as a 99-cent bottle of Coke.

That was then. Today, 2.0-liter engines propel high-powered sport sedans, elegant roadsters and roomy crossover SUVs.

“This is a huge transformation in the industry,” said Tom Murphy, executive editor of Wards AutoWorld magazine, which publishes the influential 10 Best Engines list.

After building mediocre four-cylinder engines for years, General Motors and Ford are at the forefront of the trend, offering high-powered small-displacement engines with the likes of Audi, BMW and Volkswagen. Japanese automakers have been slow to join the party, but Korea’s Hyundai and Kia are firmly on the bandwagon.

North American use of four-cylinder engines will grow 74 percent from 6.9 million to 12.2 million in the next 10 years, according to IHS Automotive. IHS predicts V-6 and V-8 use in North American-made vehicles will fall 17 percent to about 6 million over the same period.

The new four-cylinder engines produce as much power as six- or even eight-cylinder engines, but use less fuel and emit fewer pollutants. They achieve this thanks to turbocharging, high-pressure injection of fuel directly into the cylinders, electronic controls and new transmissions.

“Americans are willing to accept smaller engines as long as there’s power,” IHS analyst Aaron Bragman said. “This is where the industry is headed.”

The 2.0-liter direct-injection turbo won me over when I tested a Buick Regal GS last year. The engine’s 270 horsepower and 295 pound-feet of torque and 27-mpg highway EPA rating proved equally delightful on a long, fast trip. The next generation of the engine debuts in the Cadillac ATS sport sedan this summer.

“The power is off the chart. GM has polished that engine to a fine sheen,” Murphy said. Three of Wards’ 2012 winners are turbocharged, direct-injection 2.0-liter engines from BMW, Ford and GM. A fourth engine on the list, from Mazda, has 2.0 liters and direct injection sans turbo.

“The trend to 2.0-liter engines is a phenomenon,” Murphy said. “Certain brands have decided they don’t even need to offer a V-6 in their midsize sedans. The new four-cylinder engines can power the vast majority of passenger cars and crossovers. This is the next generation of muscle cars.”

There are limits, however. The early consensus seems to be that Ford’s 2.0-liter works well in the 3,998-pound Edge crossover but struggles in the larger 4,500-pound Explorer.

Today, 2.0 liters is the sweet spot, but even smaller engines are coming. Ford — which calls the combination of turbocharging and direct injection EcoBoost — will offer it on a 170-horsepower-plus 1.6-liter engine in the upcoming 2013 Escape crossover and Fusion midsize sedan. Ford reserves its 237-horsepower 2.0-liter engine for performance models of those vehicles.

“Automakers are pushing displacement down and power up,” said Bill Visnic of Edmunds.com. Witness the 160-horsepower turbocharged 1.4-liter Chrysler will offer in the new 2013 Dodge Dart compact sedan.

The odds are there’s a small, powerful four-cylinder engine in your future. I’ll take those odds and bet that you’ll love it.

Mark Phelan is the auto critic for the Detroit Free Press.