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Verified Technologies for SmartWay and Clean Diesel

Clean Diesel Technologies, Inc. – AZC Purimuffler or AZC Purifier Diesel Oxidation Catalyst (DOC)

This retrofit technology is included on EPA's Verified Technologies List for Clean Diesel.

On this page:

Technology specifications

Engine Model/Application

Highway, Heavy-duty, 4-cycle engines 1991 through 2006 engines 

Retrofit Fuel, Max Sulfur 15 parts per million (ppm)
Reduction in particulate matter (PM) 20%
Reduction in nitrogen oxide (NOx) n/a
Reduction in hydrocarbons (HC) 50%
Reduction in carbon monoxide (CO) 50%

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Criteria to achieve emission reductions

The following criteria must be met in order for appropriately retrofitted engines to achieve the aforementioned emission reductions: 

  1. The engine must be operated on ultra-low sulfur diesel fuel (ULSD) of 15 ppm or less.
  2. The engine exhaust temperature must achieve at least 150 °C during its duty cycle.
  3. This verification includes catalyst substrates with different cell densities. AZC DOC’s converter part numbers beginning with A16D and converter mufflers beginning with A17D prefixes employ 300 or 350 cells per square inch (cpsi) substrates which may be used on 1991 to 2006 model year engines. AZC DOC’s converter part numbers beginning with A16C and converter muffler part numbers beginning with A17C employ 400 cpsi substrates which may be used only on 1994 to 2006 model year engines.
  4. The engine must be well maintained and not consume lubricating oil at a rate greater than that specified by the engine manufacturer.
  5. The vehicle may not be equipped with an oil burning system and lube oil or other oils may not be mixed with the fuel. 
  6. The engine must not have been originally certified or equipped with a DOC or diesel particulate filter.

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Verification Letter from EPA

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