NOPEC Corporation to certify urban bus rebuild/retrofit equipment

20 November 1997

US EPA announced that a notification of intent to certify urban bus retrofit/rebuild (UBRR) equipment submitted by NOPEC Corporation is available for public review and comment, and initiated a 45-day period during which comments can be submitted. The notification describes equipment consisting of biodiesel fuel additive in combination with a particular exhaust system catalyst. If certified, the equipment can be used by urban bus operators to reduce the particulate matter of urban bus engines. The equipment is applicable to petroleum-fueled Detroit Diesel Corporation (DDC) two-stroke/cycle engines originally equipped in urban buses from model year 1979 to model year 1993, excluding the 1990 model year DDC model 6L71TA engines.

The NOPEC notification of intent to certify is unique in that the NOPEC candidate equipment conforms to the specifications of equipment previously certified by EPA, which was supplied by Twin Rivers Technologies, Limited Partnership, and is described in a Federal Register document dated 22 October 1996 (61 FR 54790). The NOPEC notification relies on the same emissions certification data that is the basis of the Twin Rivers' certification. Both the emissions test data and biodiesel specification referenced in the NOPEC notification, are public information. The testing used to demonstrate the emissions performance of the Twin Rivers' equipment was conducted under the auspices of the National Biodiesel Board, which has indicated in a letter to EPA that the data is in the public domain. Additionally, as with the Twin Rivers' equipment, the NOPEC equipment utilizes the same Engelhard exhaust catalyst and, with some configurations, fuel injection retard. The NOPEC equipment must use the "CMX'' catalyst muffler units supplied by Engelhard and meeting the specifications covered by Engelhard's certification of 31 May 1995. EPA requires that use of catalysts of any other specification, or supplied by any other catalyst supplier, be the subject of a separate notification of intent to certify. The technical specifications for the CMX are confidential information available to EPA.

The emissions test data indicate that PM is reduced by 41.1% on the MUI engines (24.5% with 4 degrees retard) and 45.0% on DDEC engines (40.0% with 1 degree retard). No configuration of the candidate equipment is certified for the 6L71TA MUI of model year 1990, because the MUI test engine was determined not to be a ``worst-case'' test engine as required by the program regulations. EPA believes that most of the reduction in PM emissions from the kit is probably attributable to the exhaust catalyst, although some additional PM emissions reduction is expected to be realized from addition of biodiesel.

Under Option 1 of the UBRR program, operators could use the NOPEC equipment if certified to reduce PM by at least 25%, or other equipment certified to provide at least a 25% reduction, unless equipment is certified which triggers the 0.10 g/bhp-hr PM standard. The 0.10 g/bhp-hr standard has been triggered for 6V92TA MUI engines, such that rebuilds or replacements after 14 September 1997 must be performed using equipment certified to the 0.10 g/bhp-hr standard. The configuration of B20 blend, Engelhard catalyst, and injection retard has been demonstrated to comply with the standard to reduce PM by at least 25%, but only when used with the following engines: 6V92TA DDEC I and DDEC II, and 6L71TA DDEC. Operators who choose to comply with Option 2 and install the NOPEC equipment, would use the PM emission level(s) established during the certification process, in their calculations for target or fleet level as specified in the program regulations.