Mean and Green: Next-Gen Turbochargers
Apr 10, 2012 5:00 AM PT
Turbochargers once were associated more with high performance than with efficiency. New turbocharging systems, however, tell a different story. By using otherwise wasted exhaust to provide a power boost, they allow car manufacturers to create smaller engines that act more like larger ones.
"Turbocharging used to be a technology that was widely associated with pure performance gains," Mike Stoller, director of communications for Honeywell, which designs and builds turbochargers, told TechNewsWorld.
"In recent years, though, it has enabled engine downsizing, and in doing so you're getting a greener technology because the engine is more efficient," he pointed out. "With the turbocharging, you're not sacrificing performance or power."
Honeywell's turbochargers are a part of the engines of many manufacturers, including Ford, Chevy, Dodge, Fiat, BMW and Mercedes.
Until recent years, turbocharging has been popular primarily in the European market, Stoller said, but because of new regulations and consumer demand for powerful, fuel-efficient vehicles, the U.S. is catching up.
"The truth is that turbocharging is relatively new as a mass technology in the U.S.," said Stoller. "In this case, the U.S. is an emerging market."
A Turbocharging Primer
Essentially, turbocharging works by capturing exhaust gasses that would normally go out the tailpipe and recirculating them back into the engine, where they drive a turbine wheel connected to a compressor wheel. A turbocharged engine, therefore, has more power than a naturally aspirated one.
With turbocharging, an engine burns fuel more efficiently and allows a smaller engine to do the work that traditionally a larger engine would have done. And because of this extra power, a turbocharged engine can deliver higher fuel economy -- up to 20 percent higher than a naturally aspirated engine of the same size.
Turbochargers can be used in gasoline, diesel, hybrid, and even natural gas engines, and they're becoming a vital part of car manufacturers' overall plans to increase efficiency and make engines smaller while maintaining or increasing their power.
Over the last several years, for instance, Ford has been offering its EcoBoost system, which has turbocharging at its heart. Available in a variety of models, including F-150 trucks, as well as the Explorer, Focus and Edge, EcoBoost lets Ford build cars with smaller engines that have the same power as their larger counterparts -- thus making cars lighter and more fuel efficient.
"With EcoBoost we can take a big engine out, replace it with a smaller engine, but we don't force the consumer to do without power," explained Richard Truett, powertrain communications manager with Ford, to TechNewsWorld.
"There is no EcoBoost without turbocharging. The turbocharger is the key to the EcoBoost system," he said.
EcoBoost has particularly changed consumer expectations of Ford's trucks. Those who needed a powerful truck once looked only at V-8s or larger engines, but now a V-6 truck engine equipped with EcoBoost provides the same power as its larger cousin.
"It's helping to rewrite the book on V-6 pickup truck engines," said Truett. "The thing that makes the V-6 [with EcoBoost] work so well in a pickup truck is the power that it puts out."
Very Light Car
Concept car company Edison2 is also experimenting with turbochargers in order to create a light, powerful and efficient vehicle it calls the "Very Light Car." The car has a small, single-cylinder engine, and the turbocharger gives it the power it needs in a variety of situations.
"We needed to run the engine efficiently in two completely different modes -- cruise and power," explained Ron Mathis, chief of design for Edison2. "We needed good efficiency at low power. We only needed about 6 horsepower at highway speeds. We also needed to make acceleration and hill climbing targets."
Turbocharging the engine was the only way to accomplish all of these goals while keeping the car small, light, and efficient, Mathis said.
"If you run a big enough engine, that engine gets progressively less efficient as you throttle it more," he explained. "There's naturally a conflict between the power that a car needs in short bursts and what it needs continuously. A turbo is absolutely the best thing available to bridge that gap."
Because of all their advantages, argued Mathis, turbocharged engines are going to become increasingly mainstream.
"I think there's a strong future for turbocharging," he said. "It's such a natural thing to do. It used to be seen as a performance add-on, but now the turbo becomes part of the whole system. The reasons not to have turbocharging are disappearing."