CARB, Suppliers Debate Diesel in U.S.

Officials from Cummins Inc. and the California Air Resources Board agree to disagree on some issues when it comes to diesels, but still are able to share a few laughs following the sparring during a panel discussion at the SAE World Congress.

John Wall, chief technical officer of diesel-engine producer Cummins, and Tom Cackette, chief deputy executive officer of the diesel-doubting CARB, debated the technology alongside Kevin DeHart of Robert Bosch Corp. and Brian FitzGerald of Siemens VDO Automotive. Strict emissions regulations kick in for diesels in the U.S. in 2004.

CARB's objection to diesels stems largely from health concerns. “Diesel emissions kill people,” says Cackette. He says particulate emissions contribute to 17,000 deaths every year, and as many as 2,900 of those were caused specifically by diesel emissions, he claims.

Some in the crowd of more than 500 questioned Cackette's claim, but he says CARB's data is based on dozens of epidemiological studies. Emissions of particulate matter, oxides of nitrogen and, to a lesser extent, unburned hydrocarbons, have remained challenges for diesel developers.

The other panel members focused on the tremendous performance and emissions improvements of new diesel engines equipped with high-pressure, common-rail fuel systems that eliminate clatter, improve mileage (by 25% or more compared to an equivalent gasoline engine), reduce emissions and give a spirited torque punch.

This technology is helping diesels gain rapid acceptance in Western Europe, where 43% of new light vehicles are expected to have diesel engines by 2005.

Still, the impending CARB-backed emissions regulations, as well as bad memories from the early 1980s, make diesels a difficult sell in the U.S. market.

Plus, diesels are more expensive. The Volkswagen AG turbodiesel comes with a $1,400 retail price premium. But DeHart, vice president-Diesel Fuel Systems at Bosch, says that premium gets canceled out at about 33,500 miles (54,000 km), based on the diesel's reduced fuel consumption.

Diesels also are a less-expensive alternative to gasoline-electric hybrid vehicles, DeHart says. Improving fuel economy by 1 mpg (0.4 km/L) with a diesel engine costs about $150 per vehicle; the same improvement with a hybrid can cost $700 per vehicle, he says.

“It will be 2020 before the hybrid segment is significant,” DeHart says. “The diesel is the best interim solution for the North American market.”

Hybrids on the road currently from Honda Motor Co. Ltd. and Toyota Motor Corp. combine gasoline engines with electric motors.

Why haven't diesel hybrids been considered? Wall, of Cummins, says it's a matter of cost.

“We've done business studies on diesel hybrids, and it's hard for these things to pay for themselves,” Wall says.

In the end, Cackette says he is optimistic about the potential for diesels in lower-volume, light- and medium-duty pickups because the auto industry has made meaningful technological strides and likely will continue to do so.

And Wall says the strong turnout at the 8 a.m. panel discussion, on a snowy morning, suggests interest in diesels may be strong enough to drive the segment forward in the U.S. “Why else would you all come out in Detroit on a cold day to hear this talk?” Wall asks the crowd.