Athletes understand that proper breathing is crucial to maintaining peak efficiency beneath all conditions and so do Chevrolet powertrain engineers. Obtaining air in and exhaust gases out with the combustion chamber under all speeds and driving circumstances is essential to outstanding drivability and fuel efficiency with reduced emissions.
“Whether powered by 4, six or eight cylinders, virtually each and every current Chevrolet automobile and truck from the compact Aveo and Cruze to the full-size Suburban SUV features variable valve timing (VVT) on its engine to optimize its breathing,” stated Sam Winegarden, General Motors executive director of International Engine Engineering.
The camshafts are driven by chains from the crankshaft to help keep the valve opening in sync with the motion of the pistons within the cylinders.
Through continuous adjustments with the camshaft phasing, engineers can accomplish smoother idle control with out sacrificing the capability to breathe at higher engine speeds. This capability contributes to the three.6-liter V6 within the Chevrolet Camaro generating 312 horsepower whilst obtaining an EPA-estimated 30 mpg on the highway.
Chevrolet’s VVT system utilizes a hydraulic mechanism to twist the camshaft relative to the crankshaft position so that the valves can be opened and closed earlier or later. On dual overhead cam engines like the Ecotec inline-four and the 3.0 and 3.6-liter V6, the intake and exhaust cams could be adjusted independently, permitting the valve overlap – the time that intake and exhaust valves are each open – to be varied also.
The 60 degrees of camshaft adjustment available on the turbocharged 1.4-liter Ecotec that powers the Cruze enabled engineers to eliminate the conventional exhaust gas recirculation program to simplify the general engine packaging – the way the engine fits in the automobile – and nonetheless decrease emissions.
“Bookending the Chevy lineup, the VVT-equipped Cruze Eco achieves an EPA estimated 42-mpg highway while the full-size Silverado XFE pickup is estimated at 22 mpg highway, both of which are best-in-class figures for their respective segments” stated Winegarden. “In fact, the 2011 Cruze Eco is the most fuel effective gasoline-fueled vehicle in America.”
Founded in Detroit in 1911, Chevrolet celebrates its centennial as a global automotive brand with annual sales of about 4.25 million vehicles in much more than 120 countries. Chevrolet provides consumers with fuel-efficient, safe and dependable vehicles that deliver high quality, expressive style, spirited performance and value. The Chevrolet portfolio consists of iconic performance cars like Corvette and Camaro; dependable, long-lasting pickups and SUVs like Silverado and Suburban; and award-winning passenger cars and crossovers like Spark, Cruze, Malibu, Equinox and Traverse. Chevrolet also provides “gas-friendly to gas-free” options including Cruze Eco and Volt. Cruze Eco provides 42 mpg highway while Volt provides 35 miles of electric, gasoline-free driving and an additional 344 miles of extended range. Most new Chevrolet models offer OnStar safety, security and comfort technologies including OnStar Hands-Free Calling, Automatic Crash Response and Stolen Automobile Slowdown. More information regarding Chevrolet models can be found at www.chevrolet.com