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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.

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Technology specifications

Engine Model/Application

On-highway, 4-cycle, EGR and non-EGR, 250-500 hp heavy-duty diesel engines; originally manufactured model years 1998 - 2006 

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) 90%
Reduction in carbon monoxide (CO) 85%

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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 be greater than 240°C for 40% of operation. As there may be significant variations from application to application, Johnson Matthey will review each vehicle’s operating conditions and perform temperature data-logging prior to retrofitting a vehicle with their SCRT system to ensure compatibility. In the event that a vehicle’s application and/or duty cycle changes, temperature data-logging must be repeated to confirm that engine exhaust temperature still meets the above criteria.
  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. The engine must not have a pre-existing original equipment manufacturer (OEM) DPF or have been retrofitted with a DPF.
  5. The engine may or may not have a pre-existing OEM or retrofitted diesel oxidation catalyst (DOC).
  6. 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.
  7. 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.
  8. Fuel additives may not be mixed with fuel unless explicitly approved by EPA for use with this device.
  9. The SCCRT must use diesel exhaust fluid (DEF) produced, handled and transported in accordance with ISO 22241.
  10. The vehicle or equipment shall not be sold or operated in geographic areas where the DEF solution may freeze (-11°C).
  11. 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.

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Verification Letter from EPA

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