CO Two-photon Laser Induced Fluorescence Measurements in High Temperature and Pressure Conditions

고온고압 조건에서 Two-Photon LIF를 이용한 CO 측정에 관한 연구

  • 오승묵 (한국기계연구원 친환경엔진연구센터) ;
  • 김득상 (국민대학교 자동차공학전문대학원 자동차기술연구소) ;
  • ;
  • Published : 2007.12.31

Abstract

Carbon monoxide (CO) is not only an important intermediate species in chemical reaction mechanisms of hydrocarbon fuel combustion, but also a crucial pollutant species emitted from automotive engines. To better understand the physical processes impacting CO emissions, the development of laser-based measurement techniques that can visualize in-cylinder CO distributions is desirable. Among these techniques, Laser-Induced Fluorescence (LIF) is a sensitive and species-selective detection technique capable of good spatial resolution. However, some technical matters such as deep UV excitation, severe pressure dependency of the LIF signal, and potential interference from other species have been major challenges for CO LIF application. This study is focused on investigating the feasibility of CO two-photon LIF in a direct-injection diesel engine operating at typical pressure and temperature conditions with commercial grade diesel fuel. Spectroscopic analysis shows that the CO fluorescence signal can be separated from $C_2$ Swan band or broadband fluorescence from PAHs when the signal is collected near 483 nm. The signal-to-noise ratio of CO LIF deteriorate rapidly as pressure is increased, following $P^{-1.49}$ which matches the theoretical signal pressure dependency.

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