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A new tool for SCR (selective catalytic reduction) testing is developed. This side stream test bench has an advantage to test smaller catalysts with a proper exhaust. The exhaust mass flow and temperature are adjustable. A control program is developed to adjust and save the needed parameters. NOx sensors are utilized in the test bench to measure the levels upstream and downstream of SCR reactor. In this study one SCR with a volume of 40.5 dm3 is tested with exhaust flows ranging from 400 to 600 kg/h and exhaust temperatures from 280 to 360°C. The tests are conducted using exhaust gas from a medium-speed diesel engine running on heavy fuel oil. A decrease from 75% to 99% (depending on test conditions) was observed in NOx over the catalyst. In addition HC and PM were found to decrease while CO was increased over the catalyst. The controlling of exhaust flow and temperature with the test bench succeeded with only minor errors.

Due to agricultural engines’ high average workload and operation in rural areas, substituting internal combustion engines in non-road sector is still a challenge. Utilizing sustainable solutions are therefore in key position for decarbonizing the non-road sector. To this day, the diesel engines dominate the markets because of their high efficiency. However, the simplicity and cost effectiveness of the spark-ignited engines together with renewable fuels are suggested to bring several advantages compared to the diesel engine. E.g. ethanol and bio methane are relatively simple to produce from agricultural residuals and wastes, and the raw materials are easily available around the world. Additionally, stoichiometric engines would only require a three-way catalyst (TWC) to fulfil Stage V emission regulations.