Single- and Two -Photon Fluorescence for the Detection of Nitric Oxide in an Optically-Accessible Direct -Injection Diesel Engine

Second, a two-photon NO LIF technique was developed and applied to study NO concentrations within the cylinder of the SCORE. This represents the first known application of two-photon NO LIF in an internal-combustion engine. The technique avoids many of the problems associated with in cylinder, single-photon NO PLIF measurements including: (1) fluorescence interference from the Schumann-Runge bands of hot O2, (2) broadband absorption of a UV excitation beam by in cylinder gases, and (3) difficulty rejecting scattered laser light while simultaneously maximizing fluorescence signal collection. A group of twelve closely spaced rotational lines in the A2Sigma +--X2pi (0,0) band of NO, consisting of P1 + O21(7.5--10.5), P2 + Q 12(22.5), O1(3.5), and S2(6.5) at 452.724 nm vac, coincident with the P1 bandhead was chosen for excitation. Two-photon NO LIF images were acquired throughout the combustion, expansion, and exhaust portions of the engine cycle providing useful NO fluorescence signal levels from 60° after top-dead-center through the end of the exhaust stroke. Verification that the signal resulted from NO was provided by tuning the laser to a vibrational offline wavelength. This resulted in near-zero signal levels from fluorescence and interference at in cylinder pressures greater than 20 bar. The in-cylinder two-photon NO LIF measurements were compared with chemiluminescence NO/NOx exhaust-gas measurements and showed good agreement over a wide range of engine loads from 1.4 to 16 bar gIMEP.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Martin, Glen Clifford

Contributors dc:contributor

• Chia-Fon F. Lee

• Engineering, Automotive

Language dc:language

eng

Identifier

(MiAaPQ)AAI3153376

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/83815