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Verified Technologies for SmartWay and Clean Diesel

Clean Diesel Technologies, Inc. – Purifilter - Diesel Particulate Filter (DPF)

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, medium heavy-duty, and urban bus; 4 cycle, model years 1994 - 2003, turbocharged or naturally aspirated non-EGR engines

Retrofit Fuel, Max Sulfur 15 parts per million (ppm)
Reduction in particulate matter (PM)1 90%
Reduction in nitrogen oxide (NOx)1 n/a
Reduction in hydrocarbons (HC)1 85%
Reduction in carbon monoxide (CO)1 75%

1 Baseline assumes an unmodified engine running on regular 2D (<500 ppm sulfur) fuel.

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Criteria to achieve emission reductions

The following operating criteria must be met in order for appropriately retrofitted engines to achieve the above emissions reductions:

  1. The engine exhaust temperature must be at least 280° C for at least 25% of the applicable duty cycle. (As there may be significant variations from application to application, CDTi will review actual vehicle operating conditions and perform temperature data-logging prior to retrofitting a vehicle with their PM filter system to ensure compatibility.)
  2. The engine should be well maintained and not consume lubricating oil at a rate greater than that specified by the engine manufacturer.
  3. CDTi installs a back-pressure monitor and malfunction indicator light on all vehicles equipped with a Purifilter.
  4. The engine must be operated with a fuel that contains a sulfur content of no more than 15 ppm to achieve the reductions listed above.

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Verification Letter from EPA

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