New California verifications for active DPF systems

14 April 2009

The California Air Resources Board (ARB) has verified four new active diesel particulate filter (DPF) systems. Three of the systems use electric heating or a fuel burner to support filter regeneration. Another system—the Johnson Matthey Advanced Catalyzed Continuously Regenerating Technology (ACCRT)—utilizes an active fuel injection strategy to reduce NO₂ emissions.

All four systems reduce PM emissions by at least 85% while not increasing NO₂ emissions by more than 20%, and have been designated as Level 3 Plus devices. The verified systems include:

• Johnson Matthey Advanced Catalyzed Continuously Regenerating Technology (ACCRT) system, applicable to select 2002 through 2006 model year (MY) heavy-duty diesel engines used in on-road applications. The ACCRT system includes a diesel oxidation catalyst (DOC), a catalyzed diesel particulate filter, a diesel fuel injection system, and a nitrogen dioxide decomposition catalyst. It is a passively regenerated filter, employing diesel fuel injection to reduce the NO₂ generated over the DOC and DPF. The applications must have a duty cycle with an average temperature profile greater than 240°C for 40% of the operating cycle.
• Donaldson Semi-Active Electric Filter (SEF) Muffler System, verified for select 1991 through 2006 MY diesel engines used in on-road applications, originally certified to the 0.25 g/bhp-hr PM emission standard. The SEF Muffler System employs a DOC, a heating element and an uncatalyzed diesel particulate filter.
• Cleaire Vista diesel retrofit system, applicable for select on-road vehicles equipped with heavy-duty 1993-2006 MY diesel engines, originally certified to or less than 0.1 g/bhp-hr PM standard. The primary components of the Vista system include a silicon carbide wall-flow filter, an exhaust flow conditioner, a diesel-fueled burner assembly, and a system controller. The Vista system is compatible with on-road vehicles using diesel fuel that contains up to 20% biodiesel.
• Cleaire Phoenix diesel retrofit system, conditionally verified for certain rubber-tired off-road vehicles. The Phoenix system is an off-road version of the Vista filter with fuel burner regeneration.

Source: California ARB