Chevrolet Cars and Trucks Get More With Less by Breathing Right x Continuously variable valve timing (VVT) available on most Chevrolet models x Four-, six- and eight-cylinder engines continuously adjust air flow for best economy and lowest emissions PONTIAC, Mich. – Athletes understand that proper breathing is critical to maintaining peak performance under all conditions, and so do Chevrolet powertrain engineers. Getting air in and exhaust gases out of the combustion chamber under all speeds and driving conditions are essential to providing outstanding driveability and fuel efficiency with low emissions. “Whether powered by four, six or eight cylinders, virtually every current Chevrolet car and truck – from the compact Cruze to the full-size Suburban – features continuously variable valve timing (VVT) on its engine to optimize its breathing,” said Sam Winegarden, executive director, Global Engine Engineering. With VVT, camshafts are driven by chains from the crankshaft to keep the valve opening in sync with the motion of the pistons in the cylinders. The VVT-equipped Cruze Eco, with EPA-estimated highway fuel economy of 42 mpg, is the most fuel-efficient gasoline-fueled vehicle in America. VVT also contributes to the full-size Silverado XFE’s segment-best 22 mpg highway. Chevrolet’s VVT system uses electro-hydraulic actuators between the drive sprocket and camshaft to twist the cam relative to the crankshaft position. Adjusting the cam phasing in this manner allows the valves that are actuated by that camshaft to be opened and closed earlier or later. On dual overhead cam engines such as the Ecotec inline-four and the 3.6-liter V-6, the intake and exhaust cams can be adjusted independently, allowing the valve overlap (the time that intake and exhaust valves are both open) to be varied as well. On the turbocharged 1.4-liter Ecotec that powers the Cruze, the cams can be adjusted by up to 60 degrees, so that the amount of exhaust gas that remains in the combustion chamber can be optimized. This eliminates the need for a conventional exhaust gas recirculation system and simplifies the overall engine packaging. Through continuous adjustments of the camshaft phasing, powertrain engineers achieve smoother idle control without sacrificing the ability to breathe at higher engine speeds. This is why the 3.6-liter V-6 in the Chevrolet Camaro generates 323 horsepower while getting an EPA- estimated 30 mpg on the highway. About Chevrolet: Founded in Detroit in 1911, Chevrolet celebrates its centennial as a global automotive brand with annual sales of about 4.25 million vehicles in more than 140 countries. Chevrolet provides consumers with fuel-efficient, safe and reliable vehicles that deliver high quality, expressive design, spirited performance and value. The Chevrolet portfolio includes iconic performance cars such as Corvette and Camaro; dependable, long-lasting pickups and SUVs such as Silverado and Suburban; and award-winning passenger cars and crossovers such as Spark, Cruze, Malibu, Equinox and Traverse. Chevrolet also offers “gas-friendly to gas-free" solutions including Cruze Eco and Volt. Cruze Eco offers 42 mpg highway while Volt offers 35 miles of electric, gasoline-free driving and an additional 344 miles of extended range. Most new Chevrolet models offer OnStar safety, security and convenience technologies including OnStar Hands-Free Calling, Automatic Crash Response and Stolen Vehicle Slowdown. More information regarding Chevrolet models can be found at http://www.chevrolet.com. ### .