Coaxing Miles From a Chevy Redesign

As New Fuel Standards Loom, the Malibu Gets a New Grille, Tail Lights; Sorry, No Spare Tire

When General Motors Co. GM -0.66% began work on its next generation Chevrolet Malibu three years ago, its engineers early on made its trunk lines more angular and chose tail lights that protruded slightly, allowing the car to go one tenth of a mile further on a gallon of fuel than the previous model.

The new back end and tail lamps on the 2013 Malibu, due in showrooms early next year, are examples of the small but important engineering changes that GM and other auto makers are making as they drive toward new fuel-economy targets.

After rising just 10 mpg in the last 30 years, the nation's fuel economy regulations are poised to rise at least an average of two miles a gallon a year for the next decade. By 2025, the average new vehicle is required to get 54.5 miles per gallon.

Those increases are forcing companies to rethink how they design their vehicles. Honda Motor Co. 's 2012 Civic has specially coated engine pistons that reduce friction. The result is a 2% improvement in fuel economy. The 2012 Toyota Motor Corp. Camry weighs 150 pounds less than this year's model. Chrysler Group LLC put a more fuel-efficient, eight-speed transmission in its 300 sedan. The car will get more than 30 miles a gallon, compared to 27 mpg in the current model.

In the case of the Chevrolet Malibu, GM engineers spent three years on changes that eked out at least five miles a gallon, creating a car that will go at least 92 more miles on a tank of gasoline compared to the current model. Slicker aerodynamics were just part of their bag of tricks. Lighter materials, such as an aluminum roof, and computer-controls that shut off the engine when idling and open and close grille vents also were part of the mileage boosters.

Active air shutters allow air into the engine compartment only as needed. A car is more aerodynamic when the shutters are closed, but can easily overheat without some airflow. Such shutters until recently were found almost exclusively on expensive sports and luxury cars.

GM shows off how it uses "smoking" in a wind tunnel to improve aerodynamics of vehicles. This is a demo of a test on the 2013 Chevy Malibu.

"A lot of what we're doing on this car was considered cost prohibitive on less expensive vehicles" in the past, said John Bednarchik, the GM engineer in charge of the Malibu's aerodynamics. "With the new [fuel-economy] requirements, we're willing to do what we wouldn't have before," he said.

Of course, such gains are just the first step. Auto makers must increase the average fuel economy of their fleets to 35.5 mpg by 2016 from 27.3 mpg today. By 2025, cars must get double today's fuel economy. That will require the small changes seen in the 2013 Malibu to give way to a more dramatic use of battery-power and hybrid vehicles.

GM achieved fuel savings by using lighter materials, giving the Malibu a new six-speed transmission instead of last year's five-speed shifter, and using a smaller, direct fuel-injection engine that creates the feeling of more power.

An "eco" version of the Malibu has a lithium-ion battery pack and compact electric motor that kicks in to give the vehicle additional power during acceleration and helps recharge the battery while slowing. That model will get an estimated 38 miles a gallon on the highway.

The new Malibu, like the Hyundai Motor Co. Elantra, also lacks a spare tire. Instead, the sedan will come with a lightweight portable air compressor and a can of liquid sealant to fix any flats. Overall, the lack of a spare and new materials reduce the weight of the car by 128 pounds from the current model. The estimated fuel economy savings from that weight loss: 0.4 miles a gallon.

When GM initially set out to redesign the Malibu three years ago, its engineers and designers were given targets to improve the sedan's weight, cost and fuel efficiency. Then, in 2008, fuel prices spiked to $4 a gallon and those targets jumped. A year later, the Obama administration came out with its stricter fuel economy requirements for 2012-2016 model-year vehicles and the goalposts moved again.

The end result illustrates how the mpg race is changing vehicle design. The Malibu on the road today has a flat back end and tail lights that are flush with the rest of the car—a look that GM debuted when it overhauled the car four years ago.

The front end of the new car has more subtle creases and curves that allow it to cut through the air more easily. Designers, engineers and executives spent hundreds of hours huddled around the car in a wind tunnel to perfect all the details.

"We are concentrating on every detail of this car—it takes looking at every single gram and kilogram and every part of the car," said Tim Campbell, the Malibu's engineering manager.

Write to Sharon Terlep at
