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SAE Reveals Growing Divide in U.S. Powertrain Strategies

When it comes to diesels, biofuels and hydrogen-powered fuel cells, there is clear disagreement among engineers. The issue of making engines capable of burning E85 ethanol is especially contentious.

Special Coverage

SAE World Congress

DETROIT – As a fresh round of stringent new rules for fuel economy and carbon-dioxide emissions looms on the horizon after 2016, the world’s auto makers increasingly are choosing divergent paths for meeting those standards in the U.S., especially in the area of alternative fuels.

Executives from major U.S., European and Asian auto makers speaking at the SAE World Congress here agree the internal-combustion engine will be the dominant powertrain for the next 15 years or more. They also agree ICEs must continue to downsize and lose cylinder counts in order to meet new efficiency standards.

And the officials concur that rules enacted after 2016 will force them to continue down a path of vehicle electrification, even though the sales outlook for battery-electric and hybrid vehicles is uncertain and likely to account for only a few points of market share over the next five to 10 years.

The value of stop/start systems, gasoline-direct injection; turbochargers; dual-clutch transmissions; automatic transmissions with six, seven, eight and even nine speeds; and cylinder deactivation; all are almost universally agreed upon as important new technologies for improving efficiency and emissions.

But when the subject turns to diesels, biofuels and hydrogen-powered fuel cells, there is clear disagreement. The issue of making engines capable of burning E85 ethanol, a mixture of 15% gasoline and 85% ethanol, is especially contentious.

The Detroit Three, which sell a higher percentage of thirsty fullsize pickups and SUVs than foreign-based competitors, earn important fuel-economy credits from the Environmental Protection Agency to build vehicles that are E85 compatible, even though there’s only a few thousand E85 pumps scattered around the U.S. and most cars and trucks never burn a drop of the alternative fuel.

Critics say ethanol fuel production is a lavish subsidy for agriculture and a gift to the politically powerful corn lobby in Washington. Proponents argue it is powerful home-grown alternative to foreign oil that is becoming more attractive every day as gasoline prices soar.

E85 also is easy to integrate into the current U.S. refueling infrastructure, unlike gaseous fuels such as natural gas or hydrogen. Whatever the case, most foreign-based auto makers are not keen on the strategy.

“We don’t see a value in E85, and we don’t need the CAFE (corporate average fuel economy) credits,” says John Juriga, director-North American Powertrain at the Hyundai-Kia America Technical Center.

Hyundai is not planning to sell diesels in the U.S., even though the South Korean auto maker offers many diesel-powered vehicles in Europe and Asia, he says.

Critics argue diesel fuel prices are too volatile in the U.S. and can soar higher than gasoline prices. Diesel engines also are more expensive than their gas counterparts and require more complex emissions-control systems.

These drawbacks caused U.S. and most Japanese auto makers to cancel plans for light-duty diesels in the U.S. Dan Kapp, director-Powertrain Research and Advanced Engineering at Ford, says the auto maker’s EcoBoost strategy that combines turbocharging with DGI delivers close to diesel efficiency at a fraction of the cost.

This attitude flusters German auto makers, which sell 50% or more of their vehicles in Europe equipped with diesel engines. They are forging ahead with diesels as a key part of their strategy for meeting CAFE regulations in the U.S.

Their strategy appears to be working after a slow start. Volkswagen, Audi, Mercedes and BMW all are seeing robust sales for their diesel offerings here, especially cross/utility vehicles. The relative cost of diesel fuel compared with gasoline still is an issue, but perhaps less a concern when all gasoline engines offered by an auto maker demand premium gas.

“One in every three BMW X5 CUVs sold in the U.S. now is powered by a diesel,” says Hans Hohenner, general manager and development drivetrain product manager for the BMW Group.

Fuel-cell powered vehicles are another area of powertrain development where strategies have diverged. Some auto makers appear to have abandoned fuel cells altogether, so they can spend their development dollars elsewhere. But others, including Honda, General Motors and Hyundai, continue to research efforts and operate test fleets.

Takashi Moriya, senior chief engineer at Honda Research and Development, gives a hint as to why his company continues to pursue fuel-cell technology:

Honda’s latest fuel-cell vehicle can hit 100 mph (161 km/h) and travel 240 miles (386 km) on one tank of hydrogen gas. It also can be refueled in three or four minutes, rather than the hours it takes to recharge a battery.

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