EPA grants Cummins
Dec 24, 2008 3:33 PM
The Environmental Protection Agency (EPA) has granted Cummins Power Generation Inc a new and limited variation in the emission-related scheduled maintenance interval for the exhaust gas recirculation (EGR) valve for some heavy duty engine families for model years 2007-2009, according to information published December 24 in the Federal Register.
EPA has approved the 67,500 mile service emission maintenance interval as suggested by Cummins. However, the agency has limited this approval to the 2007-2009 model years due to the expectation that EGR valve-related technologies compatible to NOx adsorption technology will be developed by the 2010 model year.
EPA received information from Cummins indicating that it was technologically necessary to perform cleaning and maintenance to the EGR valve more frequently than 100,000 miles, as is prescribed in 40 CFR 86.1834-01(b)(3)(vi)(H), to meet the emission standards. In part, this minimum service interval is included in the regulations to ensure that the control of emissions is not compromised by a manufacturer's overly frequent scheduling of emission-related maintenance, according to the information.
The agency received information from Cummins indicating that its NOX aftertreatment system, which utilizes cooled EGR and a NOx (nitrogen oxide) adsorber catalyst, a technology that did not exist prior to 1980, and thus new. The information received from Cummins indicates that the EGR valve requires cleaning to maintain the performance of NOx adsorption technology for emission compliance. Sulfur regeneration requires a net rich air/fuel mixture which can produce significant amounts of unburned hydrocarbon and carbon in the exhaust gas. These unburned hydrocarbons (soot) can adhere to engine components including the EGR valve which ultimately affects engine and emission performance. Therefore the EGR valve requires cleaning maintenance to remove the soot build-up prior to the 100,000 mile maintenance interval prescribed in 40 CFR 86.1834-01(b)(3)(vi)(H).
The notice can be seen in the Federal Register online.
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