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Verified Technologies for SmartWay and Clean Diesel

Johnson Matthey Technology—Selective Catalytic Reduction Technology (SCRT)

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

On this page:

Technology specifications

Engine Model/Application

On-highway, 4-cycle, non-EGR, 250-500 hp heavy-duty diesel engines; originally manufactured from model years 1994 - 2002 

Retrofit Fuel, Max Sulfur 15 parts per million (ppm)
Reduction in particulate matter (PM) 90%
Reduction in nitrogen oxide (NOx) 70%
Reduction in hydrocarbons (HC) 95%
Reduction in carbon monoxide (CO) 90%

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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 aforementioned emissions reductions:

  1. Must be operated on ULSD fuel (15 ppm).
  2. Engine exhaust temperature must satisfy both of the following conditions: a) greater than 240° C for 40% of operation; and b) greater than 200° C for 65% of operation. As there may be significant variations from application to application, Johnson Matthey will review actual vehicle operating conditions and perform temperature data-logging prior to retrofitting a vehicle with their SCRT system to ensure compatibility.
  3. Engine’s exhaust must produce a NOx/PM ratio of at least 8, with an optimum approaching 20. (Johnson Matthey will assess the suitability of candidate engines, based upon the applicable emission standards or emission test data.)
  4. Each installation will be equipped with a monitoring system that displays warning light(s) visible to the operator for low urea tank level, high back pressure, high inlet temperature and system abnormalities. The monitoring system will also store diagnostic error codes related to urea tank level and system malfunctions.
  5. The vehicle shall not be equipped with a crankcase oil burning system and the engine should be well maintained and not consume lubricating oil at a rate greater than that specified by the engine manufacturer.
  6. The vehicle or equipment shall not be sold or operated in geographic areas where the urea solution may freeze (-11° C).
  7. To ensure the appropriate urea is purchased, the customer is required to maintain urea purchase receipts and refill records and make them available to Johnson Matthey upon request. Urea usage log and mileage records will be collected and analyzed by Johnson Matthey on a biannual basis.
  8. To ensure that urea is readily available, the system will only be offered to centrally fueled fleets that have or are planning to have urea refilling capability.

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Verification Letter from EPA

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