Ammonia Distribution Measurement on a Hot Gas Test Bench Applying Tomographical Optical Methods

Bernhard Fischbacher, Bernhard Lechner, Bernhard Brandstätter

Research output: Contribution to journalArticle


Measuring the distribution of gas concentration is a very common problem in a variety of technological fields. Depending on the detectability of the gas, as well as the technological progress of the sector, different methods are used. In this paper, we present a device and methods to detect the ammonia concentration distribution in the exhaust system of diesel engines in order to increase the performance of the exhaust aftertreatment system. The device has been designed for usage on a hot gas test bench simulating exhaust gas conditions. It consists of multiple optical beams measuring ammonia line concentrations by applying nondispersive absorption spectroscopy in the deep ultraviolet region. The detectors consist of photodiodes allowing high sampling rates up to 3 kHz while providing a high signal-to-noise ratio. A detection limit of only 1 ppm has been achieved despite the short path length of only eight centimeters. The obtained line concentrations form an inverse problem. The methodology of the tomographic techniques is described in detail in order to best solve the inverse problem and obtain the ammonia concentration distribution images for each time step.

Original languageEnglish
Article number896
Number of pages12
JournalSensors & Transducers
Issue number4
Publication statusPublished - 21 Feb 2019


  • ammonia
  • deep ultraviolet
  • selective catalytic reduction
  • spectroscopy
  • tomography

ASJC Scopus subject areas

  • Analytical Chemistry
  • Instrumentation
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering
  • Biochemistry

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