US EPA initiated the comment period on the notification of intent to certify equipment filed by Engelhard Corporation. Engelhard has applied for certification of equipment applicable to all Cummins L-10 engines that were originally manufactured prior to and including 1993.

The notification of intent to certify states that the candidate equipment will reduce PM emissions 25% or more on diesel engines that have been rebuilt to Cummins specifications. Pricing information has been submitted with the notification, along with a guarantee that the equipment will be offered to all affected operators for less than the incremental life cycle cost ceiling. Therefore, this equipment may trigger program requirements for the 25% reduction standard. If certified as a trigger of this standard, urban bus operators will be required to use this retrofit/rebuild equipment or other equipment certified to provide a PM reduction.

The equipment being certified is a "Catalytic Converter Muffler" or CMXTM, that is a muffler containing an oxidation catalyst. The CMX is intended to replace the standard muffler previously installed in the engine exhaust system. The CMX is intended to be maintenance free, requiring no service for the full in-use compliance period. The engine fuel to be used with this equipment is standard diesel fuel with a maximum sulfur content of 0.05 wt.% sulfur.

Engelhard presented exhaust emission data from testing a 1992 280hp Cummins L-10 EC (electronic control) engine. Two tests were conducted, one test was performed on the engine without the CMX and a second test was performed on the same engine after retrofit with the CMX. The test data show a PM level of 0.105 g/bhp-hr for the base engine without the CMX, and a PM level of 0.073 g/bhp-hr with the candidate equipment installed. This represents a PM reduction of 30% with candidate equipment installed. Fuel consumption is not affected when the candidate equipment is installed based on comparison to the test results.

EPA notes that the selection of the test engine can not serve as the "worst case" interpretation in accordance with EPA regulations. Based on the worst case definition in the regulations, at this time EPA believes that the Engelhard's certification may only be applicable to the 1992-1993 L-10 EC engine model.

For further information contact: Anthony Erb, Engine Programs & Compliance Division (6403J), US Environmental Protection Agency, tel.: (202) 233-9259.