Detroit: Even as electric cars stall with Americans, another fuel-saving technology is revolutionising the morning commute: the turbocharger.
Once mostly the province of expensive sports and luxury cars, turbochargers are proliferating in everything from budget compacts to burly pickup trucks. As automakers scramble to lift their average fuel economy to 54.5mpg by 2025 — the target set by the US Environmental Protection Agency — turbochargers have become a key to unlocking higher mileage without sacrificing the performance consumers demand.
In the process, analysts say, their efficiency has had the unintended effect of helping slow the broader adoption of alternative-fuel vehicles. How does it work? A turbocharger essentially reuses hot exhaust gases — energy that would otherwise be wasted — to increase engine power in a smaller space.
Hot exhaust spins a turbine wheel at up to 250,000rpm, which compresses air and stuffs it into engine cylinders, allowing more fuel to be burnt in a same-size engine.
That allows automakers to shrink engines, using six cylinders instead of eight, or four in place of six, while matching the power of the larger traditional engine. The downsized engines also beat their larger counterparts in low-end torque, a boon to effortless acceleration.
“It’s really a mini jet engine in your car,” said Michael Stoller, spokesman for Honeywell Transportation Systems, which supplies turbochargers to automakers around the globe.
The result is about 10-30 per cent better fuel economy, often in conjunction with direct fuel injection, which increases efficiency via precise, computer-managed sprays of atomised fuel. With those advantages — bountiful power and savings at the pump — consumers and automakers are fully on board.
By any industry standard, the pace of the turbocharger revolution has been breathtaking.
In 2011, less than 7 per cent of new cars and trucks in America were sold with turbochargers. In just four years, that percentage has tripled to 21 per cent. Honeywell forecasts that nearly four in 10 new cars and trucks in America will be turbo powered by 2019, or roughly 8 million a year. By 2025, turbocharged engines are expected to be found in a staggering 80 per cent of new cars.
Edmunds.com, the consumer auto website, says that nearly 50 per cent of the 350 car and truck models sold in America offer a turbocharged engine, up from 30 per cent in 2010.
Make that 100 per cent at Ford, which has been especially gung-ho: For 2015, every Ford and Lincoln car, sport utility vehicle and light-duty pickup offers an optional EcoBoost turbo. Seven EcoBoost choices range from a petite 1-liter, 3-cylinder in the Fiesta subcompact — smaller than many motorcycle engines — to the 2.3-litre, 310-horsepower version in the all-new Mustang, the first 4-cylinder in any Mustang since 1986. Atop the power heap is the V6 with 365 horses in the radically redesigned F-150 pickup.
Even traditional pickup buyers, notoriously sceptical of rapid technological change, have been won over: Half of Ford’s F-series buyers, or well over 350,000 in a typical year, are choosing an EcoBoost-powered truck. The F-series with a compact 2.7-litre EcoBoost V6 set a mileage record for full-size gasoline pickups at 26 highway mpg. Yet this roughly 4,500-pound truck still accelerates faster than some sport sedans, going from stoplight to 60mph in about six seconds.
Seeing the writing on the wall, several manufacturers have dropped V6 engines entirely from their most popular family sedans, including from the Hyundai Sonata, Chevrolet Malibu and Ford Fusion, in favour of turbocharged 4-cylinder engines.
Yet as with every car, including hybrids, mileage may vary. A heavy foot spools up the turbo for a boost of acceleration, but takes an unavoidable toll on economy.
Even Bob Fascetti, vice-president of Ford’s global power trains, succumbs to the temptation. “They’re so fun to drive that I try to use all that torque,” Fascetti said. “But when you drive with just the power you need, you do get the efficiency. It’s nice to give the customer the option to drive any way they want.”
Stoller of Honeywell said that that dual nature was a key. “If you’re travelling 60mph, where you only need 50 horsepower to maintain that speed, you’ve got a lighter and more efficient engine,” he said. “But you can still step on it and pass somebody.”
Japanese automakers have been somewhat slower to get aboard, focusing more on hybrid technology.
Yet turbos are seguing into every imaginable vehicle, including $15,000 subcompacts, plug-in hybrids like the BMW i8 and $1 million supercars. In Europe, which got a bighead start in small engines, 67 per cent of showroom cars are turbos, including virtually every diesel.
In the US, Audi helped pioneer turbos decades ago and sprinkles them throughout its line-up. Keen for any one-upping edge with luxury buyers, Mercedes-Benz, BMW, Cadillac, Porsche, Ferrari and Aston Martin are revamping line-ups with turbos of 400, 500, even 600 horsepower. Aston Martin — famed for silken, yet gas-guzzling V12 engines — recently sold Mercedes a 5 per cent company stake in exchange for components including Benz’s downsized, biturbo V8 engines.
Stoller said that regulatory pressures and turbocharging’s ability to complement other fuel-saving technologies were driving the full-spectrum appeal.
