Four-Cylinder Engines Are Smaller, Quieter and Gaining New Respect (original) (raw)

Aug. 13, 2010

AS automotive earth saviors go, electric cars and hybrids are widely presumed to be the chosen ones.

But as carmakers and consumers seek real, affordable gains in miles per gallon, it will be the once-humble 4-cylinder combustion engine that takes them there far more than electrics or hybrids, which are years away from selling in numbers that would rein in the nation’s greenhouse emissions and appetite for oil.

The new allure of 4-cylinder engines certainly defies the odds. From the ’70s through the ’90s, as Japan rode small cars to world-changing success, Detroit’s compacts were poor ambassadors for the 4-cylinder. American economy cars like the Chevrolet Vega and Ford Escort limped along with base-level 4s that were often rackety, unreliable and weak-kneed. When trucks, particularly brutish S.U.V.’s, became King of the Hill in the new millennium, buyers reflexively chose a V-6 or a thirsty V-8.

Today, though, American buyers shifting to smaller cars and lighter crossovers are discovering downsized engines strong enough to meet their needs. So far this year, 47 percent of new vehicles have 4 cylinders under the hood, according to J. D. Power & Associates, a remarkable jump from 30 percent in 2005. Over that time, the market share of burly V-8s has fallen to 16 percent, from 26 percent.

Family sedans, long a litmus test for the American family, show more consumers skipping an optional 6-cylinder for a fuel-efficient 4. Through July, 93 percent of Nissan Altima buyers chose the 4-cylinder version, up from 85 percent in 2007, just before fuel prices soared and the car market tanked. The 4-cylinder version of the Ford Fusion, which attracted 55 percent of buyers in 2007, now accounts for over 70 percent of sales.

Those buyers are finding engines much more refined than the 4s of their parents’ generation still stingy on gas, but surprisingly smooth and powerful. So much so that the modern engines, girded with power-aiding technologies like turbochargers and direct injection, can beat many V-6s in both horsepower and fuel economy. And the likelihood that Formula One cars, the epitome of racing technology, will soon switch to 4-cylinder engines might convince even a jaded small-engine skeptic.

Civilizing the 4-cylinder engine, a popular power source for vehicles in the United States dating back to the Model T, once posed a huge challenge. While in-line 4s can be elegantly simple, the up-and-down motion of their pistons produces an annoying and unavoidable imbalance that grows with engine size.

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ABOUT FACE General Motors is building its 2011 Buick Regal with two 4-cylinder engines — but no V-6 or V-8.

Modern 4-cylinders provide relief from the buzzing through the use of technologies that can quell the inherent noise and harshness, including counterbalance shafts, sophisticated combustion controls and improved sound deadening and engine mounts.

An alternate plan, used by Subaru today (and Volkswagen in earlier times), is to design engines that don’t generate the jitters in the first place. Boxer engines, whose four cylinders are laid flat in 180-degree opposition, naturally cancel out most vibration, without a need for balance shafts.

But while boxer 4s (or even the V-4 engines used in many motorcycles) offer advantages in smoothness, automakers say that their modern in-line 4s are smooth enough to satisfy even the fussiest customers.

Still, for consumers like Jennifer and Jarid Lukin of Ardsley, N.Y., saving fuel and money remains the biggest lure. The recently traded their 6-cylinder Acura TL for a new Honda Accord EX-L and its 190-horsepower 4. The Accord is rated at 25 m.p.g. in combined city and highway driving by the E.P.A., compared with 21 for the Acura.

“With our lifestyle, we didn’t need a 6-cylinder,” Ms. Lukin said. “The 4-cylinder isn’t a racecar, but I’m not racing to day care.”

Hybrids, Ms. Lukin said, might post even better mileage, but also cost thousands of dollars extra upfront. “We’re saving money right now, and in the long term,” she said.

Those kind of consumer calculations spurred Hyundai to draw up what seemed a bold strategy only a year ago: to build its 2011 Sonata family sedan with only 4-cylinder engines, no optional V-6. Now that choice seems prescient.

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GREENER Ford’s redesigned Explorer will be offered with a 2-liter EcoBoost 4.

The midsize Sonata is selling well with a 2.4-liter, direct-injection 4 that is the strongest and most frugal in its class: 200 horsepower with 35 highway m.p.g. Compare that with 1990, when the Sonata’s 4 produced a puny 116 horsepower and just 25 highway m.p.g.

“These are good times,” said John Krafcik, chief executive of Hyundai Motor America. “Americans aren’t counting cylinders any more.”

This fall, the Sonata will offer a turbocharged 4 that combines 274 horsepower with a highway rating of 34 m.p.g. A Sonata Hybrid will harness an electric motor, lithium-polymer batteries and, yes, a gas 4-cylinder, to return roughly 38 m.p.g.

General Motors’ Buick division has matched Hyundai’s strategy with its 2011 Regal sedan. A version of the stylish Opel Insignia sold in Europe where even big autobahn sedans rely on smaller gasoline or diesel engines the midsize Regal offers a choice of a 182-horsepower 4-cylinder or a 220-horsepower turbo version.

Smaller engines also trim vehicle weight and development costs, and not simply because they are lighter or have fewer parts. Engineers, Mr. Krafcik said, did not have to spend time designing a stronger chassis for the Sonata to support a V-6 version.

“If you have a V-6 in the lineup, it makes the 4-cylinder version heavier than it needs to be,” Mr. Krafcik said.

Let’s not overlook the green elephant in the room; this trend is not driven entirely by consumer demand or environmental consciousness on the part of automakers. Around the world, downsized engines are the linchpin of strategies to meet stricter fuel-economy and pollution rules, including limits on carbon-dioxide emissions.

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DEEP BREATHER Buick Regal’s turbocharged 4 produces 220 horsepower.

In the United States, the regulatory bar calls for new cars and trucks to average at least 34.1 m.p.g. by 2016, a level that would result in emissions of 250 grams of carbon dioxide per mile driven. That carbon cutoff is itself momentous: cars will need to improve mileage to about 37.8 m.p.g., up from the current 27.5 m.p.g., with trucks rising to 28.8 m.p.g. from 23.5 today.

Even at companies like Ford, which has ambitious plans for electric vehicles, leaders say that downsizing engines in mainstream products will save vastly more fuel than will hybrids, diesels or electrics and at much lower cost to consumers.

Ford has pledged to put 1.3 million of its EcoBoost engines on the road by 2013 two-thirds of them 4-cylinder versions and to offer them in 80 percent of its model lineup. Brett Hinds, Ford’s manager of advanced engine design, called EcoBoost “the cornerstone of our sustainability efforts.”

“A hybrid can have a big impact per vehicle, but the numbers sold are relatively small,” Mr. Hinds said. “EcoBoost engines can have a large-scale impact on global carbon dioxide, fuel consumption and oil imports.”

Of course, if gasoline stays relatively affordable, Americans may resist the small-engine gospel and backslide into big V-8s. But Mike Omotoso, powertrain forecaster for J. D. Power, said more consumers were resigning themselves to a world of higher-price gas and choosing their cars accordingly.

Ford is placing a big industry bet with the redesigned Explorer, looking to restore sales and shine to what was once America’s top-selling S.U.V. The 2011 model will offer an optional turbocharged 2-liter EcoBoost with 4 cylinders, a count that might have seemed laughable in the Explorer’s heyday.

Yet that pint-size engine produces a surprising 237 horsepower and 250 pound-feet of torque just 5 pound-feet less than the 3.5-liter V-6 alternative, with the tradeoff that it makes 53 fewer horses. It’s also expected to deliver about 19/27 m.p.g. in city and highway driving, according to Ford, a 30 percent improvement from the previous Explorer’s V-8.

Relying on the architecture of the Ford Taurus, the new Explorer now a car-based crossover shaves several hundred pounds from the old pickup-based version, making a small engine more suitable. That engine alone trims nearly 100 pounds, and as with the Sonata, weight savings snowballed through the design. While the pricing isn’t official, Ford has said it will charge more for the EcoBoost model than for the V-6 version. Some customers, Mr. Hinds acknowledges, may resist paying extra for an engine with fewer cylinders. Yet test-driving the EcoBoost Explorer, he said, would bring skeptics into the growing 4-cylinder fold and have them convincing friends that bigger isn’t always better:

“I drove the 2-liter Explorer, and it was great,” is what Mr. Hinds hopes they will be saying.

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