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Verified Technologies for SmartWay and Clean Diesel

Clean Diesel Technologies, Inc. – Purifilter Plus 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, medium, and light heavy-duty, and urban bus, 4 cycle, model years 1994 - 2006, 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 fuel with less than 15 ppm sulfur.

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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. As there may be variations from application to application, data-logging and a review of actual vehicle operating conditions is required to ensure Purifilter Plus compatibility. CDTi will provide a recommended schedule for active regeneration of the device.
  2. In most applications, the Purifilter Plus must be periodically actively regenerated with the off-board regeneration control panel. The frequency of active regeneration will vary based on vehicle use or other conditions.
  3. The engine should be well maintained and not consume lubricating oil at a rate greater than that specified by the engine manufacturer. Lubricating oil may not be mixed with engine fuel with this technology.
  4. CDTi installs the Back-Pressure Monitor and Logger unit and the Remote Driver Display on all vehicles equipped with a Purifilter Plus.
  5. The engine must be operated with a fuel that contains a sulfur content of no more than 15 parts per million (ppm).

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Verification Letter from EPA

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