Near-term fuel-economy increases will come from incremental improvements

  • 19-Jun-2008 04:19 EDT

At the SAE World Congress in April, Chrysler LLC Vice President of Powertrain Product Engineering Robert Lee said carmakers will have to pay the cost of fuel-economy improvements in the short term.

Incremental improvements to the gasoline engine remain at the forefront of the race to meet the 35 mpg by 2020 regulation—a 40% increase—and recent price increases in diesel fuel may limit diesel engine inroads to light trucks, an SAE 2008 World Congress panel on fuel economy agreed. World refinery limits on additional diesel fuel production also could maintain price pressures on the fuel. In addition, the new emphasis on low carbon emissions might work against diesels if improvements in gasoline engines bring them much closer to diesels.

The forum, “Will Fuel Economy Sell and Can We Afford it?,” largely focused on what the customer would be willing to pay, and the answers were not encouraging. Scott Miller, CEO of Synovate Research, said his company’s surveys indicated that a third of all motorists are unwilling to pay anything, and another 17% have an under-$1000 limit.

That was not surprising, Miller said, considering that half the motorists surveyed did not even realize that “internal-combustion engine” was what was powering their cars.

Although diesels and plug-in hybrids are coming, incremental improvements in gasoline engines are the least costly, and have been yielding annual 1 to 3% increases in fuel economy, according to Scott Bailey, Vice President of Delphi Powertrain. However, some of those increases have been lost to safety and performance changes.

The cost issue was discussed first by Robert Lee, Vice President, Powertrain Product Engineering, Chrysler LLC. “If the incremental cost for energy-efficient conversion to meet the 35-mpg mandate is $100 per percentage point—$4000 per car—and we built one million cars…[and even if] the customer will pay $1800 per car, we have a loss of $2.2 billion.”

“In the short term, the automakers will pay for fuel economy, but the long-term cost will eventually [have to be] borne by the customer,” he added.

Lee said that just as reducing household energy use goes well beyond investing in a new furnace, Chrysler is looking for improvements in the whole car, including weight/inertia, aerodynamic drag, rolling loads, accessory loads, and drivetrain losses. But he noted that he has to deal with a fragmented customer base. When it comes to selling small cars, for example, the physical size of Americans is a factor; two-thirds of them are overweight.

Delphi’s Bailey said that $1800—or about $40 to $45 per percentage point improvement in fuel economy—was an “aggressive” cost objective to achieve the full 40% improvement necessary to meet the 35-mpg mandate. He said he hoped it could be achieved with the incremental powertrain improvements, changes in braking and accessory systems, and reductions in drag and rolling resistance. Variable valve timing and cylinder deactivation, he said, had yielded an improvement of about 5 to 7%—about $30 per point.

The emphasis on affordable solutions is what led Ford to introduce turboboosting of its V6 engines, to be used in place of V8s, explained Andreas R. Schamel, Chief Engineer, Engine Engineering, Research and Advanced Engineering, Ford Motor Co.

“It mitigates the traditional disadvantages of downsizing and boosting, and keeps fun-to-drive at reasonable cost,” he said. The payback at $3/gal is 2.5 years, he noted, vs. 7.5 years for diesels and 10 years for hybrids. Recent price increases in diesel fuel and the high cost of meeting diesel emissions standards may push the payback time out to 20 years, he added.

Schamel said that only the spark-ignition (SI) engine is compatible with all forms of alternative fuels, from hydrogen to biofuels. 

He said that in the near term, Ford would concentrate on SI engine enhancements, aerodynamic improvements, and wider use of six-speed automatic transmissions. Mid-term, he said, weight reductions of 250 to 750 lb (113 to 340 kg) per vehicle and reductions in engine displacement would follow.

Noting that Ford’s model sales mix has shifted slightly from high-profit SUVs and trucks to small cars such as the Focus, he added that the challenge is “to make the small car profitable.”

Although hybrids are more expensive and complex, Toyota has sold 1.3 million worldwide (about 750,000 in the U.S.), and they account for 10% of Toyota sales here, said Tom Stricker, Director of Technology and Regulatory Affairs, Energy and Environmental Research, Toyota. Hybrids are a Toyota core technology, he said, but the company must move into other areas to meet fuel-economy regulations. The Tundra and Sequoia soon will have a diesel engine, he noted.

“The future is not optional,” Stricker said. “We have to find ways to make fuel economy sell.” Toyota is attacking the hybrid’s cost issue, he said. Since introduction, he added, Toyota has taken 70% of the cost of the hybrid technology out of the Prius, improved its fuel economy 30%, and increased the dimenions of the vehicle from small to full-size.

Synovate’s Miller also put a real-world perspective on fuel economy vs. other considerations in the motorist’s mind. His research showed the most desired cars are Lexus, Mercedes-Benz, and BMW. If fuel economy were the sole driver, the No. 1 choice would be Kia, followed closely by Honda, Toyota, and Hyundai.

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