Verified Technologies for SmartWay and Clean Diesel

Clean Diesel Technologies, Inc. – AZC Purimuffler or AZC Purifier Diesel Oxidation Catalyst (DOC) plus CDTi Closed Crankcase Ventilation (CCV) System

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

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Technology specifications

Engine Model/Application

Highway, heavy-duty, mechanically or electronically injected, turbocharged or naturally aspirated; originally manufactured from 1991 through 2006 model years which meet a 5 or 4 g/bhp-hr NOx standard

Retrofit Fuel, Max Sulfur 15 parts per million (ppm)
Reduction in particulate matter (PM) 25%
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

This technology is approved for use with an open crankcase ventilation and no after treatment engines. The following criteria must be met in order for appropriately retrofitted engines to achieve the aforementioned emission reductions:

  1. Pre-installation and post installation inspections are to be performed to insure correct functioning of the installed CCV. The CCV filter indicator must be used to access blow-by rates are satisfactory. The pre and post installation inspections must be documented for each vehicle.
  2. The filtered oil from the CCV must be returned back to the engine oil sump. There is no catch bottle to be used with the CCV system.
  3. The engine must be operated on ultra-low sulfur diesel fuel (ULSD) of 15 ppm or less.
  4. The engine exhaust temperature must achieve at least 150 °C during its duty cycle.
  5. 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.
  6. The engine must be well maintained and not consume lubricating oil at a rate greater than that specified by the engine manufacturer. 
  7. The vehicle may not be equipped with an oil burning system and lube oil or other oils may not be mixed with the fuel.
  8. The engine must not have been originally certified or equipped with a DOC or diesel particulate filter.
  9. The 4500 and 6000 model filter cartridges must be replaced every 750 engine hours or every other oil change or when indicated by red filter service indicator, whichever occurs first. The 3500 and 3550 model filter cartridges must be replaced every oil change or when indicated by the red service indicator, whichever occurs first.

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Verification Letter from EPA

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