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EPA to test Cummins 2010 engine
By Jill Dunn
The U.S. Environmental Protection Agency will soon start testing Cummins 2010 on-road diesel engines after expressing concerns the manufacturer’s process has the potential to catalyze dioxin, a likely human carcinogen.
The agency’s Dec. 11 letter to the manufacturer targeted its use of copper zeolite to drive the nitrates of oxide reduction reaction. The EPA’s long-held concern is copper potentially can catalyze dioxin formations in incinerators and diesel exhaust, said Karl Simon, director of compliance and innovative strategies division of the agency’s National Vehicle and Fuel Emissions Laboratory.
“If the data are inconclusive or show increased dioxin emissions, then EPA likely will not certify an engine family utilizing such products unless a manufacturer can provide data which demonstrates the intended use of the copper catalyst doesn’t increase dioxin emissions,” Simon wrote. “Emission test data provided for this purpose must have been conducted using sound sampling and testing protocol.”
Cummins believes the agency will make a data-based decision.and that its entire line of on-highway engines will meet federal 2010 emissions standards on time, said spokesperson Christy Nycz.
North America's largest on-highway heavy-duty engine supplier is cooperating with the EPA, Nycz said. "The EPA is working on a test methodology, and an independent research firm will be conducting their tests," she said. "In accordance with the EPA guidance letter, Cummins is conducting our own tests, and will provide the data to the EPA."
The company will meet with the agency this month to discuss its findings.
Selective catalytic reduction is an exhaust after-treatment using a urea-based liquid to neutralize oxides of nitrogen.
Originally, Cummins’ heavy-duty emissions strategy for 2010 was to rely solely on exhaust gas recirculation. But in August, based on new data, it announced it would add SCR for better fuel economy.
Nycz said Cummins had discussions on this topic with the EPA before the Dec. 11 letter. "Cummins is confident that copper zeolite based catalysts is the best technology available for meeting the EPA '10 near-zero standards," she said. "If the EPA decided to ban the use of copper zeolite, Cummins would investigate other zeolite compounds for use in the SCR catalyst."
Cummins Emission Solutions, a provider of SCR systems, will supply integrated exhaust after-treatment systems for Cummins heavy-duty and midrange engines. Cummins already had planned to use SCR in medium-duty trucks.
Cummins has said the new data established the superiority of new copper zeolite emissions technology compared to conventional iron zeolite technology commonly used in SCR particulate filters. Zeolites are essentially materials that act as molecular filtration systems. Copper zeolite technology emerged about two years ago as engineers sought more efficient exhaust gas filtration systems and became available for automotive applications in 2007.
Cummins has said copper zeolite-based SCR systems will offer improved heat rejection, lighter weight and improved fuel economy over EGR-only engines and SCR systems based on iron zeolite.
The EPA’s information gathering will begin with testing to measure the potential for dioxin formation under known worst-case conditions. An engine will be tested over several operating cycles, including steady state and the heavy-duty FTP, and with several different test configurations, including engine out, baseline, with an iron-zeolite SCR catalyst and with a copper-zeolite SCR catalyst.
The agency has requested test data from manufacturers considering copper containing SCR catalysts, but had received limited data, it said.
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