Cycle-resolved residual gas concentration measurement inside a heavy-duty diesel engine using infrared laser absorption

Nobuyuki Kawahara, Eiji Tomita, Atsushi Ohtsuki, Yuzo Aoyagi

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)


Cycle-resolved residual gas fraction measurements were made inside a heavy-duty diesel engine using an infrared absorption method. An in situ laser infrared absorption method was developed using an optical fiber sensor and a 4.301-μm quantum cascade laser (QCL) as the light source. We discuss the feasibility of obtaining in situ CO2 concentration measurements inside the engine combustion chamber using the newly developed optical fiber sensor system. Lambert-Beer's law can be applied for the case of a single absorption line of CO2, and the dependence of the CO2 molar absorption coefficient on the ambient pressure and temperature of was determined using a constant volume vessel. This coefficient decreased with increasing pressure, indicating almost constant at pressures over 1.0 MPa. CO2 concentration measurements were made in a compression-expansion engine in order to calibrate the measurement system. The feasibility of the optical fiber sensor system was then investigated in a heavy-duty diesel engine. We were able to measure the CO2 concentration inside the combustion chamber under various engine load conditions and were able to determine the internal exhaust gas recirculation (EGR) ratio. This measurement technique proved to be valuable in obtaining the cycle-to-cycle CO2 concentration of the residual gas in a heavy-duty diesel engine.

Original languageEnglish
Pages (from-to)2903-2910
Number of pages8
JournalProceedings of the Combustion Institute
Issue number2
Publication statusPublished - Feb 3 2011


  • Heavy-duty diesel engine
  • In situ infrared absorption method
  • Internal EGR ratio
  • Molar absorption coefficient of CO
  • Residual gas concentration

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Mechanical Engineering
  • Physical and Theoretical Chemistry


Dive into the research topics of 'Cycle-resolved residual gas concentration measurement inside a heavy-duty diesel engine using infrared laser absorption'. Together they form a unique fingerprint.

Cite this