Characterization of laser-induced ignition of biogas-air mixtures

Christian Forsich, Maximilian Lackner, Franz Winter, Herbert Kopecek, Ernst Wintner

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


Fuel-rich to fuel-lean biogas-air mixtures were ignited by a Nd:YAG laser at initial pressures of up to 3 MPa and compared to the ignition of methane-air mixtures. The investigations were performed in a constant volume vessel heatable up to 473 K. An InGaAsSb/AlGaAsSb quantum well ridge diode laser operating at 2.55 μm was used to track the generation of water in the vicinity of the laser spark in a semi-quantitative manner. Additionally, the flame emissions during the ignition process were recorded and a gas inhomogeneity index was deduced. Laser-induced ignition and its accompanying effects could be characterized on a time scale spanning four orders of magnitude. The presence of CO2 in the biogas reduces the burning velocity. The flame emissions result in a much higher intensity for methane than it was the case during biogas ignition. This knowledge concludes that engines fuelled with biogas ultimately affect the performance of the process in a different way than with methane. Methane-air mixtures can be utilized in internal combustion engines with a higher air-fuel ratio than biogas. Comparing failed laser-induced ignition of methane-air and biogas-air mixtures similar results were obtained. The three parameters water absorbance, flame emission and the gas inhomogeneity index constitute a suitable tool for judging the quality of laser-induced ignition of hydrocarbon-air mixtures at elevated pressures and temperatures as encountered in internal combustion engines.

Original languageEnglish
Pages (from-to)299-312
Number of pages14
JournalBiomass and Bioenergy
Issue number3
Publication statusPublished - Sept 2004
Externally publishedYes


  • Biogas
  • Combustion
  • Diode laser
  • In situ
  • Laser ignition
  • Laser spectroscopy


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