Industrial Marine Silencers Develops Stage V Retrofit SCRT System For Inland Waterways Marine Market

In January 2019, the European Parliament adopted “Stage V” emission limits for the “Internal Combustion Engines” installed in “River Based Vessels”

by Alan Barnard | Monday 29 March 2021

Emission limits are for main and auxiliary engines with power ratings <300 kW, which was extended to engines with power rating >300 kW from 1st January 2020.

Stage V regulation calls for limit values for gaseous emissions such as carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx) to be reduced by 70-84 percent which will require the use of oxidation catalysts and selective catalytic reduction (SCR).

For Particulate Matter (PM), particulate mass and particle numbers (PN) needs to be reduced by approximately 92 percent which requires the use of “Wall-Flow Diesel Particulate Filters”.

IMS have developed a combined DPF/SCR/ASC Reactor with an upstream DOC that can be retrofitted to existing engines to bring a Stage IIIA engine to Stage V equivalent or IMO Tier II to IMO Tier III. The system will utilise Hydrocarbon Injection in front of the DOC to “Actively” elevate the exhaust gas temperatures in order to continuously regenerate the soot captured within the Wall-Flow DPFs to eliminate any concern over potential filter blockages at low loads/low exhaust gas temperatures.

NOx is dramatically reduced by injecting AdBlue into a mixer pipe that is embedded into the SCR Reactor. The Dosing Strategy is automatically controlled by the ECU within our Electronic Control System that comes complete with On-Board Diagnostics (OBD) that can be linked to a Telematics Package if required for remote data access.

The AdBlue Injectors are “Airless” which eliminates the need for an on-board compressor saving space within the engine compartment making it easier to install.

IMS are currently installing a number of vessels operating on the River Thames in London.


Alan Barnard
Industrial & Marine Silencers Ltd
+44 1509 506792

Monday 29 March 2021 / file under Engineering | Environmental | Marine