10 August 2001

First diesel particulate filter (DPF) technologies have been verified by the California Air Resources Board (ARB) for use in California heavy-duty diesel retrofit programs. The technologies, verified on 2 August 2001, include the Johnson Matthey CRT and Engelhard DPX diesel particulate filters.

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Engelhard’s DPX filters are verified for use with Cummins M-11 and ISM heavy-duty diesel engines model years 1995-2001. Verified applications include refuse haulers, school buses, urban buses, fuel tanker trucks and long-haul trucks and buses. Johnson Matthey’s CRT filters are verified for use with DDC Series 50 and 60 engines model years 1998-2000 in refuse hauler, school bus, fuel tanker truck, long haul truck, urban and long haul bus applications. Applications from both manufacturers for verifications covering other engine families and applications are being processed.

Both filters have been verified as “Level Three” retrofit devices reducing particulate matter (PM) emissions by at least 85% over an emission durability period of at least 150,000 miles. The DPFs must be operated with ultra low sulfur diesel fuel (15 ppm S). The DPFs are passive devices, which self-regenerate at exhaust gas temperatures typically occurring in regular operation of the engines. Engelhard’s DPX filters require an average exhaust gas temperature of at least 225°C. Johnson Matthey’s CRT filters require an exhaust temperature of at least 270°C for 40% of the operating cycle and a minimum NOx/PM ratio of 8, with a preference for NOx/PM ratio of 15 or higher. Both DPF systems will include backpressure gauges and indicator lights.

Verified DPFs can be now used in heavy-duty diesel retrofit programs which, under the Diesel Risk Reduction Plan adopted last September, are to be implemented in California over the period of 2002-2008. The retrofit may include as many as 75% of the over 1 million population of in-use diesel engines in California.

Source: California ARB