Ever wonder exactly how the 2011 GMC Terrain crossover can achieve a segment-leading fuel-economy mark of 32 mpg highway and an impressive 22 mpg city—the same ratings as a four-cylinder Toyota Camry? Well, it turns out that a key enabler of this feat was the efforts of GMC engineers to pump up the volume in terms of fuel efficiency by dialing down the noise elsewhere.
Here’s the story: The Terrain team set out to help customers attain this kind of stellar fuel economy by incorporating a driver-selectable “Eco” mode that can be engaged with a quick click of a button. In this mode, the shift points of the Terrain’s six-speed automatic are adjusted so that the clutch engages at lower engine speeds, which helps save fuel. However, the system also created a low-frequency “booming” noise that was far out of character for a Professional Grade product like the Terrain.
The solution? Inspired by the active noise-cancelling technology available on high-end audiophile headphones, GMC developed a similar type system for the Terrain. The setup leverages two microphones hidden in the Terrain’s headliner, which were designed to sense unwanted hum in the cabin, and an onboard frequency generator that emits sound waves to counteract the noise, via the crossover’s speakers and subwoofer.
That work has paid off, too. According to Jim Vallance, a noise, vibration and harshness development engineer for General Motors: “Terrain measured quieter than the Honda CR-V and Toyota RAV4 in our on-road interior noise tests,” while “At 70 miles per hour, Terrain’s interior is quiet enough to allow conversation in normal tones of voice.”
For more information on the Terrain, visit Indiana GMC Dealers or your local GMC dealer.
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