Optical Diagnostics of Laser-Induced and Spark Plug-Assisted Hcci Combustion

Martin Weinrotter, Ernst Wintner, Kurt Iskra, Theo Neger, Jimmy Olofsson, Hans Seyfried, Marcus Aldén, Max Lackner, Franz Winter, Andreas Vressner, Anders Hultqvist, Bengt Johansson

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HCCI (Homogeneous Charge Compression Ignition),
laser-assisted HCCI and spark plug-assisted HCCI
combustion was studied experimentally in a modified
single cylinder truck-size Scania D12 engine equipped
with a quartz liner and quartz piston crown for optical
access. The aim of this study was to find out how and to
what extent the spark, generated to influence or even
trigger the onset of ignition, influences the auto-ignition
process or whether primarily normal compressioninduced
ignition remains prevailing. The beam of a Qswitched
Nd:YAG laser (5 ns pulse duration, 25 mJ
pulse energy) was focused into the centre of the cylinder
to generate a plasma. For comparison, a conventional
spark plug located centrally in the cylinder head was
alternatively used to obtain sparks at a comparable
location. No clear difference in the heat releases during
combustion between the three different cases of ignition
start could be seen for the fuel of 80/20 iso-octane/nheptane used.
However, with optical diagnostic
methods, namely PLIF (Planar Laser-Induced
Fluorescence), Schlieren photography and
chemiluminescence imaging, differences in the
combustion process could be evaluated.
Original languageEnglish
Pages (from-to)284-295
JournalSAE Transactions, Journal of Engines
Issue number3
Publication statusPublished - 2005

Subject classification (UKÄ)

  • Other Mechanical Engineering
  • Atom and Molecular Physics and Optics


  • Spark Ignition
  • Laser Ignition
  • Engine
  • HCCI
  • Combustion
  • Optical Diagnostics


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