Form Enhances Function: Chevy Traverse’s Wind-Cheating Design Helps It Deliver Expected Segment-Best Fuel Economy
DETROIT – Besides its bowtie insignia, the all-new Traverse crossover shares something important with Chevy’s midsize cars: an exceptional aerodynamic drag coefficient (cd) that enables great fuel economy. Its cd is only 0.33 – making it the sleekest crossover in the segment.
When it hits showrooms this fall, the Traverse is expected to have the segment’s best highway fuel economy (EPA certification is pending). This is because of its new, efficient 3.6L V-6 with direct injection technology, a fuel-saving six-speed automatic transmission and an exterior designed to cheat the wind and slip through the air with minimal resistance.
“In every way, the Traverse is an uncompromising vehicle,” said Michael Burton, Traverse design director. “It has a ‘gotta have it’ design with fuel economy that rivals many sedans.”
In an example of form and function working harmoniously, designers crafted the Traverse’s sleek look while simultaneously infusing it with the expressive styling that was introduced last year on the acclaimed Chevy Malibu. That includes refined details with strong proportions and the bold front-end appearance found on all new Chevrolets.
“Aerodynamic performance was central to the Traverse’s development, but so was maintaining the identity of Chevrolet,” said Dan Schmeckpeper, lead creative designer, Traverse exterior design. “We designed a vehicle with all the cues – a twin grille, power dome hood, etc. – that make it unmistakably a Chevy, with efficiency that complements its style.”
In the wind tunnel
The Traverse casts a unique profile with a sleek, smooth and flowing design that carries built-in aero enhancers, such as an integrated rear spoiler and splitter at the bottom of the air dam. Those details contribute to the Traverse’s excellent aerodynamic efficiency, which was honed after repeated trips to the wind tunnel at GM’s Technical Center in Warren, Mich.
Clay and foam models of the Traverse were tested and re-tested in the wind tunnel during the development period, as engineers sought every advantage to maximize fuel efficiency. A one-tenth improvement in the coefficient of drag increases overall fuel economy by about a tenth of a mile per gallon.
“The Traverse is efficient by design,” said Justin D’Souza, aerodynamic engineer. “From the first wind tunnel tests of the initial design to the finalized shape of the production model, we picked up the equivalent of nearly two miles per gallon when cruising on the highway.”
The Traverse’s aerodynamic enhancements also draw upon lessons learned during the development of other GM midsize crossovers.
“GM’s midsize crossovers were already the most aerodynamic in their class,” said D’Souza. “We took the Traverse to the next level by building on the experience of an already-efficient design and making it even better.”
Examples of aerodynamic performance that were enhanced during development include:
The front fascia, headlamps and hood were re-shaped after initial testing to cut a sleeker profile
The front splitter (at the bottom of the air dam) was added to the Traverse after initial wind tunnel testing, resulting in a one-tenth of a mpg improvement
The cowl (area below the windshield) and A-pillars were revised for improved airflow, which also helped reduce wind noise
The shape and radius of the wheel openings were revised and drag-reducing rear tire air dams were added to the design
The rear spoiler angle was redesigned in the wind tunnel
Extensive fine-tuning of the backlight and taillamps was performed for the just-right balance of styling and efficiency
Additionally, much attention was paid to details such as the gaps between exterior components and even the relationship of the tires to the vehicle body. Smaller, more precise gaps between exterior panels reduce drag, while a tighter tire-to-body relationship improves overall aerodynamics.
The depth and shape of the grille was scrutinized, as well.
“Grille openings and textures are huge contributors to drag, but they’re necessary to provide cooling airflow to the powertrain and air conditioning system,” said D’Souza. “On the Traverse, we tested a number of configurations and came up with a grille design that delivers Chevy’s trademark styling and detail, uncompromised cooling performance and minimized aero drag.”