SCR-catalyst utilisation and mixing comparison using a novel biomimetic flash-boiling injector

Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceeding


NOx pollution from Diesel engines causes over 10 000 premature deaths annually and the trend is increasing. In order to decrease this growing global problem, exhaust after-treatment systems for Diesel engines have to be improved. The most common SCR systems in the market place inject an aqueous Urea solution, DEF that evaporates prior the catalytic surface of the SCR-catalyst. Due to a catalytic reaction within the catalyst, NOx is converted nominally into Nitrogen and Water. Currently, the evaporative process is enhanced by aggressive mixer plates and long flow paths; these, negatively, create extra exhaust back pressure and cool the exhaust gases decreasing engine and catalyst efficiency. To achieve future emission legislation targets SCR efficiency has to be improved especially under low catalyst temperature conditions, plus Ammonia slip has to be avoided as it is now legislated against. Swedish Biomimetic’s novel µMistR platform technology, inspired by the Bombardier Beetle, injects a hot, effervescent, finely atomised, highly dispersed spray plume of DEF into the exhaust stream. This is achieved by raising the temperature of the DEF, in a closed volume, above its saturated vapour pressure. The DEF is then rapidly released creating effervescent atomisation. This study investigates a back to back study of the evaporating and mixing behaviour of the µMistR injector and a class leading DEF injector. The test conditions are with and without a mixer plate and the use of two different flow path designs. Spray distribution across the face of the catalyst is assessed by measuring NOx conversion whilst Ammonia slip is also measured post catalyst. This report describes how the novel µMistR injector significantly increases NOx conversion and catalyst surface usage whilst considerably reducing Ammonia slip.


External organisations
  • Swedish Biomimetics 3000 AB
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Energy Engineering


  • Boiling, Catalysts, Biomimetics, Ejectors
Original languageEnglish
Title of host publicationEmissions Control Systems; Instrumentation, Controls, and Hybrids; Numerical Simulation; Engine Design and Mechanical Development
PublisherAmerican Society Of Mechanical Engineers (ASME)
Number of pages7
ISBN (Electronic)9780791851999
Publication statusPublished - 2018
Publication categoryResearch
EventASME 2018 Internal Combustion Engine Division Fall Technical Conference, ICEF 2018 - San Diego, United States
Duration: 2018 Nov 42018 Nov 7


ConferenceASME 2018 Internal Combustion Engine Division Fall Technical Conference, ICEF 2018
Country/TerritoryUnited States
CitySan Diego

Related research output

Peter Larsson, 2019 Mar 4, Department of Energy Sciences, Lund University. 115 p.

Research output: ThesisDoctoral Thesis (compilation)

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Related projects

Peter Larsson, Per Tunestål, Öivind Andersson & Lars-Uno Larsson

Swedish Government Agency for Innovation Systems (Vinnova), Swedish Energy Agency


Project: DissertationCollaboration with industry

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