Engine part may resonate with buyers

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DETROIT — Ford Motor Co. has put a lot engineering into its EcoBoost line of engines, which promise improved efficiency from smaller engines, leading to improved gas mileage.

But that engineering will not draw customers if they don't like the sound of those engines.

EcoBoost uses turbo chargers along with other improvements, and turbo chargers typically have a high-pitched whine. That is not a sound most drivers want — especially if that engine is in a heavy-duty truck or sports car.

So Ford worked with a group of suppliers to develop a way to tune that sound, in the process creating a new plastic component that places an injection molded resonator inside a blow molded hot charge duct under the hood.

"You look at it, and it looks like it's just a black tube, but there's a lot of engineering that goes into it," said Mike Day, DuPont's North America automotive development director, during an interview Jan. 17 at the North American International Auto Show in Detroit.

Resonators are not new to the auto industry. They have been used previously in air-intake manifolds and other key parts. The resonator itself is designed to funnel the air passing through it into a new shape, which affects the sound — similar to the way that blowing across a bottle produces a different sound depending on the amount of liquid in the bottle.

The EcoBoost engines needed a way to package that resonator inside a duct, though, to work around the tight spaces under the hood. An early variation on the duct using metal did not provide a tight seal around the resonator, which produced an unwanted whistling sound, said Chris Murphy, global automotive industry director for Wilmington, Del.-based DuPont.

The development team included engineers from Dearborn, Mich.-based Ford, DuPont, Chevron Chemical Co. LLC of Houston, ContiTech AG — a unit of Continental AG of Hanover, Germany — and Polymer Products LLC of Owosso, Mich., and DuPont.

To finally create the two-piece blow molded duct, the team adapted a blow molding process already used in plastic fuel tanks that inserts components inside the tank during the molding cycle. It also weighs 20 to 30 percent less than a steel duct, saving a pound from the 2-liter EcoBoost engines on the Escape sports utility vehicle.

The duct is going into 1 million EcoBoost engines produced globally during 2012 and 2013, and is expected to grow from there. ContiTech already is looking at a second manufacturing cell in North America. In addition to the Escape 2-liter EcoBoost, the duct is used on the 1.6-liter Escape engine, on three engines of Ford's Kuga SUV and the Fusion, Mondeo and Focus cars sold in Europe, China and North America.

The part also was a finalist in the Society of Plastics Engineers 2012 Automotive Innovation awards.