’07 Engines Run Cleaner Than Federal Standards

This story appears in the June 29 print edition of Transport Topics.

Over-the-highway trucks and buses with 2007 engine technology ran nearly 90% cleaner than required by federal emission standards for diesel particulate matter, the key pollutant targeted that year, a recent study has found.

The study, partly funded by the Department of Energy and prepared by the nonprofit Coordinating Research Council, Alpharetta, Ga., also found that other pollutants were cut much more sharply, in some cases 99% cleaner than previous engine systems.

“These engines were significantly below the 2007 standards for most pollutants,” Jeff White, director of emissions research and development for the Southwest Research Institute, the organization that carried out many of the tests, told Transport Topics.

CRC worked with the Health Effects Institute, Boston, and Southwest Research Institute, San Antonio.

The report, published June 18, was titled “Phase 1 of the Advanced Collaborative Emissions Study” and focused solely on over-the-highway heavy-duty truck and bus engines.

The study examined exhaust emissions “from four 2007 model-year heavy-duty diesel engines manufactured by Caterpillar, Cummins, Detroit Diesel [Corp.] and Volvo,” the report said.

“More than 360,000 of these heavy-duty trucks and buses were sold in 2007 and 2008, which is why this report is so important,” Allen Schaeffer, executive director of the Diesel Technology Forum, an organization that promotes diesel technology, told TT.

The report said the research was undertaken “to quantify the reduction in both regulated and unregulated emissions from advanced diesel engines.”

The study found that the engines far surpassed the main focus of EPA’s 2007 regulations, a diesel particular matter limit of .01 grams per horsepower hour, or g/hp-hr. The engines actually registered .0011 g/hp-hr, which the report said was 89% below that 2007 level.

Heavy-duty engine makers added diesel particulate filters to their exhaust systems that year, and refined their engines’ exhaust recirculation systems. The entire package added $7,000 to $12,000 to the price of a new Class 8 truck.

The study found that other EPA regulated emissions also were much lower than the ’07 standards: carbon monoxide emissions were 98% below the standard; nonmethane hydro-carbons were 95% under the mandated level; and oxides of nitrogen oxides were 10% lower than required.

White said the four test engines were standard ’07 power plants similar to what customers bought. “These were all 2007 production engines,” he said.

“Ultimately these findings translate into even greater clean-air benefits for local communities than were previously expected,” Schaeffer of Diesel Technology Forum said. “Today’s diesel trucks and buses are so clean it would take 60 of today’s models to have the same soot emissions as one 1988 model.”

Public sector sponsors of the study included the Department of Energy, the Environmental Protection Agency and the California Air Resources Board. Private sector sponsors were the Engine Manufacturers Association, American Petroleum Institute and manufacturers of emission-control equipment.

The study showed that emissions not regulated by the EPA also dropped significantly from 1998 and 2004 engines, years in which EPA instituted tougher emission standards.

Unregulated compounds showed a reduction ranging from 38% for inorganic ions to 99% for hopanes/steranes, elemental carbon and dioxins/furans, the report said. Hopanes/steranes and “elemental carbon” are both petroleum byproducts. The EPA classifies dioxins and furans as possible toxic substances.

An EPA spokeswoman said she had not seen the report and did not have a comment.

Truck and engine makers are gearing up for a new set of standards that go into effect next Jan. 1, this time mandating a drastic reduction in NOx output.