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Verified Technologies for SmartWay and Clean Diesel

Semi-Active Electric Diesel Particulate Filter (SEF) System

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

On this page:

Technology specifications

Engine Model/Application

On-road, 4-stroke diesel engines, turbocharged or naturally aspirated for engines rated ≤400 hp, originally manufactured from model year 1991-2006, and engine family name listed in the Attachment A

Retrofit Fuel, Max Sulfur 15 parts per million (ppm)
Reduction in particulate matter (PM) 90%
Reduction in nitrogen oxide (NOx) n/a
Reduction in hydrocarbons (HC) 65%
Reduction in carbon monoxide (CO) 60%

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Criteria to achieve emission reductions

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

  1. The engine must meet at a certified PM emission level of at most 0.25 grams per brake horsepower-hour.
  2. The engine must have rated exhaust flow not to exceed 2,700 cubic feet per minute.
  3. The engine must be used by an on-road motor vehicle with a manufacturer's Gross Vehicle Weight Rating of over 14,000 pounds.
  4. The engine must be rated to no more than 400 horsepower and it must have a displacement of no more than 13 liters.
  5. The engine may be certified as having exhaust gas recirculation.
  6. The engine may be mechanically or electronically controlled.
  7. The engine must be well maintained and not consume lubricating oil at a rate greater than that specified by the engine manufacturer.
  8. The vehicle may not be equipped with an oil burning system and lube oil or other oils may not be mixed with the fuel.
  9. The engine must not have been originally certified or equipped with a diesel particulate filter.
  10. The engine must remain in its original certified configuration, except that if an OEM oxidation catalyst is present, it may be removed if the SEF System is installed. Should the SEF System be removed, the OEM oxidation catalyst must be re-installed, returning the engine to its original certified configuration.
  11. The system must be installed with a backpressure monitor to notify the operator when the backpressure limit is reached. The notification must occur and be clearly visible to the operator while the vehicle or equipment is in use.
  12. Use of the SEF system requires a Regeneration Control Station Assembly for periodic regeneration of the filter.

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Verification Letter from EPA

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