Chevrolet Volt Aerodynamics

technical center in Warren, Mich., is the center of expertise for optimizing the impact of airflow. In addition to fuel economy, range, emissions, and acceleration are all affected by wind resistance, or aerodynamic drag. The cooling of components such as radiators and brakes are affected by airflow, as is cornering capability, crosswind response, directional stability and on-center handling. GM’s aero lab allows for the testing and development of each of these characteristics.

Aerodynamics development begins with a 1/3-scale model where basic shape and major features are defined. The model includes a highly detailed underbody and engine compartment. Radiator and under hood cooling flow is developed with computational fluid dynamic models. Simultaneously, computation development takes place to determine aerodynamic drag of design alternatives. Development continues with full-scale models, where shape is refined and optimized for low wind noise. The development process concludes with a vehicle prototype validation of the math-based analysis and physical testing.

“I'm proud to say that after extensive aero development of the Volt, and more to come, we have achieved a vehicle that had a coefficient of drag that is more 30% lower in drag than the original concept,” said Welburn. “It’s not easy, but it is a necessity.”

GM’s Aerodynamic Laboratory: The Wind Tunnel

Founded in the late 1970s, GM’s aerodynamics laboratory was built in response to fuel shortages of that time and the introduction of Corporate Average Fuel Economy (CAFÉ) standards. Test operations began in 1980 with several production vehicle tests that benchmarked the wind tunnel’s performance against other facilities. All new GM vehicles for the North American market have been developed using the lab. Today, the experimental work in the aero lab is supplemented by computational fluid dynamics analysis. The combination of the two testing operations provides a powerful tool to improve aerodynamics of future GM vehicles.

Wind speed in the tunnel can reach up to more than 120 miles-per-hour. Real-time data acquisition and display systems measure forces and moments, airflow velocities, pressures, temperatures and wind noise.

In addition to helping GM create today’s most fuel efficient vehicles, wind tunnel testing has provided a competitive advantage for GM racing vehicles. Several GM sponsored teams also have taken advantage of the wind tunnel, including America ’s Cup challengers, Sunrayce solar cars, bicycle racers, the U.S. Disabled Ski Team and the Canadian Alpine Ski Team.

The GM Aerodynamics Laboratory celebrated 26 years of wind tunnel test operations in August. The lab was the first full-scale automotive wind tunnel built in North America and remains the largest wind tunnel in the world dedicated to automotive testing.

GM and Aerodynamics

GM’s history in aerodynamics dates back to the 1930s with aircraft-inspired designs as industrial art. In the 1950s and 60s the company focused more on the science of drag reduction, but in the 1970s, the public demanded smaller, more fuel efficient cars in response to fuel shortages. As a new trend in aerodynamics emerges, GM leverages its heritage and expertise to develop full-sized trucks as fuel efficient as a mid-sized sedan and the next generation of electric vehicles with extended range, starting with the development of the Chevrolet Volt.

“We are now in the midst of a new period of aero exploration,” said Welburn. “There has been a significant effort by all our program teams to improve fuel economy and now to extend the range of electric vehicles for the future.”

General Motors Corp. (NYSE: GM), the world’s largest automaker, has been the annual global industry sales leader for 76 years. Founded in 1908, GM today employs about 280,000 people around the world. With global headquarters in Detroit, GM manufactures its cars and trucks in 33 countries. In 2006, nearly 9.1 million GM cars and trucks were sold globally under the following brands: Buick, Cadillac, Chevrolet, GMC, GM Daewoo, Holden, HUMMER, Opel, Pontiac, Saab, Saturn and Vauxhall. GM’s OnStar subsidiary is the industry leader in vehicle safety, security and information services. More information on GM can be found at www.gm.com.

Date : 10 Dec 2007 16:41:53 Source: Chevrolet

Date : 10 Dec 2007 16:41:53
Source: Chevrolet