SCRT® Operating Conditions

The SCRT® - Selective Catalytic Reduction + Continuously Regenerating Trap - depends upon the use of AdBlue® for the selective catalytic reduction and upon regeneration of the filter in the CRT® to prevent large accumulations of soot and eventual filter blockage. Use of the incorrect reducing agent, poor vehicle maintenance, excessive engine smoke, oil consumption or high sulphur fuel can prevent the SCRT® system from operating satisfactorily.


The industry standard AdBlue®, an aqueous solution of urea, is used as the reducing agent in the SCRT®. Without AdBlue®, the system will not function correctly and remove NOX from the exhaust gas.

  • Only AdBlue® and no other reducing agent should be used in the SCRT® system.
  • The AdBlue® level should be checked regularly and each time the vehicle is re-fuelled to ensure the tank does not run dry any time during vehicle operation.

NB. The vehicle will continue to operate without AdBlue® but the SCRT® will not function correctly and remove NOX from the exhaust gas. No damage will be caused in this situation.

  • The freezing point of AdBlue® is -11°C. In extreme cold environments it is possible the AdBlue® stored on the vehicle could freeze. Procedures to prevent this from happening should be taken as freezing could cause damage to the storage tank and will prevent the SCRT®system from functioning correctly.


  • Use only diesel fuel with sulphur content less than 50 ppm and conforming to EN590
  • Do not use fuel additives other than those already incorporated in general commercial diesel fuel supplies.
  • Additionally the following biodiesel and water-diesel emulsion fuels are approved for use with SCRT® technology:
Greenenergy Global Diesel, 5% biodiesel, 95% ULSD
Global Commodities UK Ltd, driveEco
Rix Biodiesel Ltd, Bioblend 5
Petroplus Marketing Ltd, Bio-plus
Water-fuel Emulsions
BP Aspira @ 10% demineralised water
Lubrizol PuriNOxTM @ 10% demineralised water

Engine Smoke

The level of smoke produced by the engine should not exceed the maximum limits set by the engine manufacturer.

Engine Oil

Low ash oils are recommended to maintain the filter service interval and optimal SCRT® performance.

  • Use only engine oil with a sulphur content of less than 7,000 ppm.
  • Ensure engine oil consumption is within engine manufacturers limits, typically less than 1 litre per 1,000km.

During normal operation, ash, which is an incombustible material (mainly the residues of burnt engine oil), can gradually build up in the filter. This is removed by regular servicing.

Click here for more information on Eminox Filter Servicing

Vehicle Operation

  • The vehicle must be serviced according to manufacturer’s recommendations in order to maintain the optimal engine performance, which the CRT® system is designed to be compatible with.
  • Repeated long periods of engine idling should be avoided. This can lower the engine temperature below that required for filter regeneration, causing soot to accumulate and block the filter.