MPG: Not just for CAFE anymore
Carmakers do EVERYTHING to top each other in fuel economy; how designers and engineers are changing the car
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As they redesigned their newest generation of cars over the past few years, Hyundai Motor Co. executives relentlessly cut weight and improved fuel economy. They made strong steel thinner. They rolled out smaller but more powerful direct-injection engines ahead of the competition. They even introduced crushed volcanic rock into their interior vinyl parts to lighten vehicle weight.
And inside Hyundai, a heated debate pitted traditional customer expectations against weight reduction: Would the 2011 Elantra ditch its spare tire and jack and cut 25 pounds by substituting a can of goo that squirts into the valve to fill a tire puncture?
"We had all kinds of data that told us we shouldn't do it," says Mike O'Brien, Hyundai's vice president of U.S. product planning. "We knew there would be customer-satisfaction risks."
In the end, the goo won.
"We decided we wanted every piece of mpg we could get," O'Brien says. "We have declared fuel efficiency as one of our key priorities at Hyundai. And once you've established your priority, the decisions you make about products become a little easier."
The goo's net contribution to the car's improved fuel efficiency? One precious mile per gallon.
Such white-knuckled decision-making has made Hyundai an industry darling, with fuel-efficient vehicles that are climbing the sales charts. Its 2012 Sonata turned heads with an EPA rating of 35 mpg highway.
But stand back, Hyundai. The Sonata became the target of Nissan engineers developing the next-generation Altima, which Nissan says will blow past the Sonata's mpg this summer as it prepares to challenge the Toyota Camry as America's best-selling car. Fusions, Malibus, Imprezas, BMW 528s -- most new vehicles now leapfrog the mileage of their previous generations.
BMW: The 2012 335i, with a direct-injection engine, electric steering and auto stop-start, is only $300 more expensive than the 2011 335i.
Nissan: The redesigned 2013 base Altima with numerous fuel economy improvements costs $950 more than the outgoing base model. But the 2.5S trim level costs $210 less than the lower-mpg version it replaces. And the 2.5SV trim level, which Nissan expects to be the most popular, is only $40 more than the equivalent package of the old Altima.
After three decades of heavier vehicles and little improvement in mpg, O'Brien and others are in a breathless sprint to bring out models that dramatically move the needle on fuel economy. Some new models have leaped ahead with significant mpg gains:
• Ford's new mid-sized Fusion, due this summer, has an optional direct-injection engine that boosts highway fuel economy to a projected 37 mpg, up from 30 in the outgoing Fusion.
• Stop-start engine technology and better aerodynamics take the 2013 Chevrolet Malibu Eco to 29 mpg combined city/highway, up from 26 for the Malibu a generation ago.
• The 2012 Subaru Impreza boasts 30 mpg combined city and highway, a leap of 36 percent over the 22 combined for the Impreza in 2008.
• The Audi A6 improved from 21 mpg combined in 2008 to 28 this year, a whopping one-third better.
• The 528i that BMW introduced a year ago -- a sporty luxury sedan that no one would confuse with a gas-sipper -- now burns less gasoline than some inexpensive compacts. The 2012 model promises 27 mpg combined, including a flashy 34 for highway driving. Its 2008 predecessor delivered 21 mpg combined.
• And this month, Nissan North America introduces a redesigned Altima sedan it is touting at 38 mpg on the highway, the top highway rating among gasoline-powered mid-sized sedans. That's up from 32 on the 2012 model and is a key factor in Nissan's thinking that it can take on the Camry.
These are significant gains for an industry that made scant headway in fuel economy for three decades. But the marketplace has changed fundamentally, with forecasts for higher gasoline prices, tough new fuel-economy targets, and most of all, a new marketplace pressure to promote fuel economy as a competitive badge.
Automakers "care more about their competitors than about what the government wants," says Scott Gallett, marketing chief at BorgWarner Inc., referring to efforts to outdo rivals rather than simply meet new fuel-economy mandates. BorgWarner supplies turbochargers and other systems that reduce emissions and improve fuel economy.
Fuel economy ranked as the top shopping consideration among consumers this spring, far ahead of vehicle quality, according to a recent phone survey by Consumer Reports magazine.
Even big trucks are getting the makeover. Ford Motor Co.'s EcoBoost engine design, a combination of turbocharging and direct injection, is winning over buyers for the full-sized F-150 pickup. The V-6 EcoBoost option, which represents a 29 percent increase in mpg over the truck's regular V-8, is accounting for more than 40 percent of F-150 sales this year.
For years, manufacturers have steadily improved engine efficiency and reduced the weight of some parts, including replacing iron and steel with aluminum. But the improvements invariably disappeared under the wave of rising horsepower and increasing vehicle weights.
Over the past three decades, U.S. vehicles gained nearly 30 pounds a year on average, according to EPA data, as consumers clamored for more trucks and for weighty features such as motorized seat adjusters, DVD players and leather trim, and safety regulations required thicker doors, stronger roofs and more airbags.
Over the past 30 years, industry fuel economy has increased by just 2.5 mpg to 22.8 mpg for all light vehicles sold in the United States combined, according to EPA data. Last year's estimated 22.8 mpg average was the industry's best performance since the EPA began keeping tabs in 1975.
The fuel-economy imperative has changed.
Ralph Gilles, Chrysler Group's senior vice president for product design, told a business group two weeks ago that Chrysler knows it has to change the square look of vehicles such as the Chrysler 300 because of that imperative. Chrysler's designers are spending far more time in the wind tunnel.
"We'll have no choice but to be some of the most wind-swept vehicles that you've ever seen," Gilles said.
At Hyundai, throughout the lineup, the results speak for themselves. The redesigned Elantra comes in at 33 mpg combined city and highway driving in 2012, up from 28 combined in 2008, according to EPA data. The Accent, which debuted last year, boasted the same improved numbers. In Hyundai's aggressive marketing, both enhanced models boast 40 mpg in highway driving.
As a point of comparison, Toyota Motor Corp.'s big-selling but aging Corolla has remained unchanged at 29 mpg combined city and highway since 2005, according to EPA numbers.
For the past year, Hyundai's larger mid-sized Sonata has achieved a 35 mpg highway number. Nissan targeted the Sonata in redesigning its 2013 Altima.
The numbers are not yet official, but Nissan says the Altima has achieved 27 mpg city/38 highway and 31 combined, up nearly 20 percent from the 23 mpg city/31 highway and 26 combined of the previous-generation Altima.
 | Chrysler Group's Ralph Gilles: "We'll have no choice but to be some of the most wind-swept vehicles that you've ever seen." |
Overtaking the Sonata caused Nissan planners to use an array of techno-tactics. Among them: aluminum bumper structures, reduction of parts and friction in the car's continuously variable transmission and a broader gear ratio so the engine revs at nearly 500 fewer rpms at 60 mph than did its previous generation.
Just as Hyundai's elimination of the spare tire caused a heated discussion, Nissan had its conflicts.
John Curl, planning manager for the Altima, says the drive for fuel economy occasionally pitted engineer against designer. The team found places to improve aerodynamics. But for the past decade, Nissan Motor Co. has been carefully honing a design look under global design chief Shiro Nakamura. Project designers had to be convinced that trimming and reshaping the Altima's bumpers and side mirrors were necessary moves. In the end, they approved a series of aerodynamic improvements for the tail, windshield and underbody.
The aerodynamic improvements accounted for 15 percent of the Altima's mpg gains.
BMW AG is also hotly pursuing better aerodynamics. The automaker spent $230 million in 2008 to build its aerodynamic test center in Munich to support BMW's activity in global Formula One racing.
But BMW's values have been evolving over the past dozen years. In 2009, CEO Norbert Reithofer, a hawk in BMW's EfficientDynamics fuel saving program, pulled the plug on Formula One and redirected the racing budget into the quest for fuel economy. The Munich wind tunnel now helps engineers shape vehicle bodies to reduce wind resistance.
BMW launched EfficientDynamics in 2000 largely in response to European political demands for carbon-dioxide reductions. The program is a guiding ethos for BMW, says Tom Baloga, vice president of engineering at BMW of North America.
"Our mission is to bring down fuel consumption while also preserving our performance DNA," Baloga says. "It's the umbrella for everything we're doing. We recognized that we need to reduce fuel consumption. But every one of our cars still has to drive like a BMW."
For Baloga and his colleagues, that contradictory mission requires combining every feasible technological improvement.
 | Baloga: BMW's goal is to cut fuel use while "preserving our performance DNA." |
For its current 528i, BMW replaced the standard 3.0-liter V-6 with a new turbocharged, direct-injection, four-cylinder 2.0-liter engine that puts out 240 hp to the V-6's 230.
BMW's global sales are rising, and the company is adamant that better fuel economy will help sustain the momentum. Its German luxury rival, Audi AG, believes the same thing. For years, European automakers have faced more dramatic pressures on fuel efficiency because of much higher fuel prices, combined more recently with the European requirements to reduce carbon-dioxide emissions.
"We have to address the new social awareness about fuel concerns," explains Anthony Foulk, Audi of America's product manager for the A6, A7, A8 and Q7. "Our luxury customers might not be as sensitive to fuel prices as other consumers. But they do care more now about engine efficiency."
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Audi's Foulk (left): Buyers will care; Ford's Makowski: Multiple solutions |
Last year, the A8 flagship received a redesigned 4.2-liter engine combined with a new eight-speed automatic transmission. Engineers rechanneled the coolant system to move the refrigerant farther from the heat of the engine, pulling less power from the engine. They put new coatings on the cylinders to reduce friction and adopted LED headlights and interior lighting, which consume half the energy of halogen lights. Audi improved the aerodynamics around the wheel wells and underbody.
Audi now plans to replace hydraulic steering with electric power steering across its line.
"That's a technology that customers might not care about," Foulk says. "You won't be able to feel any difference in the new steering. But you can explain that it's almost 30 pounds lighter, which helps with fuel economy, and that is something they do care about."
Audi plans to use more aluminum. Already, the A8 body structure is all aluminum, which is more expensive than steel and trickier to bend for automaking. Audi's smaller A6 and A7 models received more aluminum content in this generation.
Foulk concedes that even Audi isn't ready to use aluminum everywhere. Riveting aluminum and steel together remains a challenge. Audi's A8 factory in Neckarsulm, Germany, is the site for its lightweight design center, where it researches using aluminum in vehicles.
Hyundai, too, seeks a leg up on metal research, using its ownership of Hyundai Steel Co. in Korea for a competitive advantage in vehicle light-weighting, O'Brien says.
"We now have more than 400 steel engineers dedicated to developing the ideal steel for us on each part of the vehicle," O'Brien says. "R&d moves faster when you own your own steel mill and your own steel r&d development center."
That alliance of carmaker and steel maker enabled the development of the Elantra's ultrathin torque converter, the heavy bagel-shaped powertrain part that transforms rotating engine power to vehicle drive. In the 2012 Elantra, Hyundai Steel made it possible to essentially slice the bagel in half and cut 2.6 pounds.
Of all the technologies and process changes that can improve mpg, the biggest gains come from changing engines. Today, new engines must be efficient enough to transition a car from a V-8 to a V-6 or a V-6 to a four without giving up power or acceleration. BMW's last U.S. four-cylinder in 1999 was a 1.9-liter offering 144 hp. Thanks to direct-injection technology, the 2.0 four-cylinder in its 528i gets 240 hp.
Chevrolet's new Malibu Eco uses an engine technology that is spreading through General Motors. The technology, called eAssist, boosts mpg by borrowing hybrid technologies.
In a normal hybrid the gasoline engine stops and the battery-powered electric drive propels the car by itself. That doesn't happen on the Malibu Eco, says Daryl Wilson, lead engineer on the eAssist program. The car's new Hitachi lithium ion battery does not power the car by itself. Instead, the battery provides power for electrical systems, such as fans, audio and lighting, that normally draw power from the engine. It also provides power to an electric motor that is mated to the engine. The motor provides up to 15 hp of additional power to the car.
The Malibu needed many other enhancements to move the needle. Aerodynamic nips and tucks accounted for a fifth of the Malibu Eco's mpg improvement to 29 mpg combined city and highway, up from 26 for the outgoing Malibu. A new regenerative braking system charges the battery.
Automatic stop-start required engineers to add an electric steering pump and an auxiliary transmission pump for when the engine is in "stop" mode. The car uses aluminum rear knuckles instead of cast iron ones and an aluminum hood instead of one made of steel.
New materials in the cabin carpet and various cockpit trim eliminate two-thirds of their weight.
Direct-injection engines figure prominently in the charge to better fuel economy. Ford will offer turbocharged direct injection on more than 90 percent of its lineup by next year, packaged under the EcoBoost marketing name.
The upcoming Escape uses a direct injection engine, mated with a turbocharger and twin independent variable cam timing. The mid-sized Fusion sedan also gets EcoBoost.
Direct injection feeds fuel directly into the combustion chamber at around 2,000 pounds per square inch of pressure. Traditional engines deliver fuel to the intake port at between 40 and 60 psi.
A longtime criticism of the auto industry is encased in a question that hovers over all this new technological deployment: Why couldn't automakers make all these changes a decade ago? Suppliers such as BorgWarner have been marketing turbochargers for decades. And big global suppliers introduced direct injection more than a decade ago.
"Everybody knew when gasoline direct-injection technology was commercially available several years ago, and it was available to everybody," Hyundai's O'Brien agrees. "It was available to purchase from Siemens, Continental, Bosch and Denso. Yet very few people took that chance. Even today, you can look around the industry and it's not in everybody's line."
Scott Makowski, Ford's global program manager for large four-cylinder engines, says the technologies are finally coming to market in a big way because they can now be made to work together.
"I get that question all the time from people," says Makowski, who has worked on Ford engine development for 24 years. "It's really about integration. It's about making different technologies work together.
"We spent a lot of time on reducing friction with new piston coatings," he says of the EcoBoost system in the upcoming Escape. "We went to polished tappets, so the rubbing surfaces of the tappet against the valvetrain would have less resistance. And we went with electric power-assist steering, so that we're not asking the engine to spin a hydraulic pump any more."
That means less parasitic drag on the engine, which in turn means less demand for fuel and a higher mpg rating in dealer showrooms now that the Escape is on sale.
"It's not just one magic technology that is going to get the job done," Makowski says. "There are a lot of them, and they all have to work together."
Ford has big plans to spread EcoBoost across its product line. It is a promising technology in a tidal wave of multiple solutions, including weight reduction, aerodynamics and start-stop engines.
Smaller engines at BMW, aluminum parts at Audi, smoother CVTs at Nissan and tire goo at Hyundai. In an era when every additional mile per gallon counts, all contributions are welcome.
| Mpg report card | ||
| 8 models' fuel economy progress (city/highway mpg) | ||
| 2012 model | 2008 model | |
| BMW 328i | 24/36 | 19/28 |
| Dodge Challenger | 18/27 | 13/18 |
| Hyundai Accent | 30/40 | 24/33 |
| Hyundai Elantra | 29/40 | 25/33 |
| Kia Sorento 2wd | 21/29 | 16/22 |
| Mercedes C350 | 20/29 | 17/25 |
| Subaru Impreza awd | 27/36 | 20/25 |
| Volvo S80 fwd | 20/29 | 16/24 |
| Source: EPA Fuel Economy Guide | ||
You can reach Lindsay Chappell at lchappell@crain.com.
