Cycle-resolved measurements of the fuel concentration near a spark plug in a rotary engine using an in situ laser absorption method

Nobuyuki Kawahara, Eiji Tomita, Kenta Hayashi, Michihiko Tabata, Kouhei Iwai, Ryoji Kagawa

Research output: Contribution to journalConference article

37 Citations (Scopus)

Abstract

Cycle-resolved measurements of the fuel concentration near a spark plug in a commercial rotary engine were performed. An in situ laser infrared (IR) absorption method was developed using a spark plug sensor and a 3.392-μm He-Ne laser as the light source. This wavelength coincided with the absorption line of hydrocarbons. The newly developed IR spark plug sensor had a higher signal-to-noise ratio than its previous version due to the optimization of its quartz lens and two optical fibers. The new sensor provided quantitative cycle-resolved fuel concentration measurements around the spark plug with a high temporal resolution. At lean preset air/fuel (A/F) ratios, fuel was mixed with the surrounding air gradually by the rotor motion in the plug hole of the rotary engine. Strong mixture inhomogeneities were measured during the compression stroke; the magnitude of these inhomogeneities decreased throughout the compression stroke. Cycle-resolved measurements were made to investigate the effects of the fuel concentration near the spark plug on the combustion characteristics of the commercial rotary engine. There was a strong correlation between the fuel concentration measured with the spark plug sensor and the combustion characteristics during the initial combustion period, which occurred faster when conditions were slightly richer than stoichiometric near the spark plug. The indicated mean effective pressure (IMEP) was slightly related to the A/F ratio near the spark plug. It was possible to measure the cycle-resolved A/F ratio near the spark plug and investigate its cycle-to-cycle fluctuations to achieve stable operation using the newly developed spark plug sensor.

Original languageEnglish
Pages (from-to)3033-3040
Number of pages8
JournalProceedings of the Combustion Institute
Volume31 II
DOIs
Publication statusPublished - Sep 24 2007
Event31st International Symposium on Combustion - Heidelberg, Germany
Duration: Aug 5 2006Aug 11 2006

Keywords

  • Air/fuel ratio
  • Cycle-to-cycle fluctuations
  • In situ infrared absorption method
  • Mixture formation process
  • Spark ignition Wankel rotary engine

ASJC Scopus subject areas

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

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