23 March 2005
The California ARB has extended the verification of the Johnson Matthey CRT™ and CCRT™ particulate filter systems to 2005-2006 Cummins ISM and ISB diesel engines which employ exhaust gas recirculation (EGR), used in on-road applications operating on ultra low sulfur diesel fuel. The CRT™ and CCRT™ are passively regenerating diesel particulate filters which achieve an 85% reduction in PM emissions, thus qualifying for a “Level 3” verification.
This is the first particulate filter verification issued for EGR-equipped engines. Operation of some EGR engines (such as those used on certain urban buses before October 2002) was negatively affected by particulate filters, apparently due to the increased backpressure levels which could upset the EGR rate control.
Source: ARB (verified devices page)