Laser Diagnostics for Applications to In-Cylinder Engine Investigations

Abstract

In the work presented in the thesis laser diagnostics was employed primarily in the investigation of engines, but was also used to study soot in flames. Quantitative measurements were performed for visualizing both in-cylinder soot formation and DME sprays in a combustion vessel. The DME sprays inside a diesel truck engine were also qualitatively investigated. The combustion process in the HCCI engine was studied as well. Two species, formaldehyde and OH, were detected there simultaneously.



Laser-induced incandescence (LII) was used in the work with soot diagnostics to measure soot concentrations, the potential for soot particle sizing also being investigated. Early in the work, various fundamental studies were performed in well-characterized flames in which results using the LII technique were compared with measurements performed by means of the scattering-extinction technique. As an extension of this work, LII was combined with an extinction measurement to provide on-line calibration of quantitative measurements of soot volume fractions. LII was also employed to investigate soot production in the cylinder of a gasoline direct-injection engine. Quantitative soot volume fraction distributions were obtained from the engine after calibrating the LII technique against a small, premixed well-defined flame.



In the second part of the thesis, the use of dimethyl ether (DME) sprays as fuel for diesel engines was investigated. Laser-Rayleigh imaging was applied to obtain quantitative images of the local equivalence ratios for the DME sprays. Before any of the engine measurements were performed, the mixing conditions of both burning and non-burning DME sprays were investigated in a chemically pre-heated combustion vessel. These measurements were followed up by in-cylinder investigation of the use of DME spray in a diesel truck engine. The development of the spray was studied from the start of injection until all the fuel was consumed.



In the final part of the work, ignition and combustion processes in the HCCI engine were investigated by means of laser-induced fluorescence (LIF). Two species, formaldehyde and OH, were imaged simultaneously. The formaldehyde formed as an intermediate during an early stage of the combustion process served as an indicator of low-temperature reactions. The OH radical, in turn, an important intermediate formed in high-temperature regions during combustion, was used as an indicator of regions in which HCCI combustion was underway. How the combustion process is affected by changes in the homogeneity of the fuel-air mixture that arises from early versus late injection timing, was investigated. During the data evaluation there was a need of defining an index of homogeneity in order to compare the homogeneity of the signal distribution in the different measurements. The effect of fuel volatility on HCCI combustion was also investigated, fuels of low and high volatility, respectively, being employed.

• author: Collin, Robert
• supervisor: Marcus Aldén
• opponent: Professor Gülder, Ömer L., Institute for Aerospace Studies, University of Toronto, 4925 Dufferin Street, Toronto, Ontario M3H 5T6
• organization: Combustion Physics
• publishing date: 2004
• type: Thesis
• publication status: published
• subject: Atom and Molecular Physics and Optics
• keywords: LII, Rayleigh scattering, formaldehyde, OH, soot, dimethyl ether, Laser technology, Fysik, Laserteknik, Physics, LIF, Laser diagnostics, combustion engines, Fysicumarkivet A:2004:Collin
• pages: 172 pages
• defense location: Room B, Department of Physics, Lund Institute of Technology
• defense date: 2004-09-17 10:15:00
• ISBN: 91-628-6141-7
• language: English
• LU publication?: yes
• additional info: Article: Axelsson B., Collin R., and Bengtsson P.-E.Laser-induced incandescence for soot particle size measurements in premixed flat flames.Appl. Opt. , 39:3683-3690, 2000. Article: Axelsson B., Collin R., and Bengtsson P.-E.Laser-induced incandescence for soot particle size and volume fraction measurements using on-line extinction calibration.Appl. Phys. B, 72:367-372, 2001. Article: Andersson Ö., Collin R., Aldén M., and Egnell R.Quantitative imaging of equivalence ratios in DME sprays using a chemically preheated combustion vessel.SAE paper 2000-01-2785, 2000. Article: Andersson Ö., Collin R., Aldén M., and Egnell R.Laser-Rayleigh imaging of DME sprays in an optically accessible DI Diesel truck engine.SAE paper 2001-01-0915, 2001. Article: Collin R., Nygren J., Richter M., Aldén M., Hildingsson L., and Johansson B.Simultaneous OH- and formaldehyde-LIF measurements in an HCCI engine.SAE paper 2003-01-3218, 2003. Article: Collin R., Nygren J., Richter M., Aldén M., Hildingsson L., and Johansson B.Studies of the combustion process with simultaneous formaldehyde and OH PLIF in a direct-injected HCCI engine.Proceedings of the Sixth International Symposium on Diagnostics and Modeling of Combustion in Internal Combustion Engines (COMODIA) ,August 2-5, Yokohama, Japan, 311-317, 2004. Article: Collin R., Nygren J., Richter M., Aldén M., Hildingsson L., and Johansson B.The effect of fuel volatility on HCCI using simultaneous formaldehyde and OH PLIF.SAE paper 2004-01-2948, 2004.
• id: e6a9e5af-8f55-4b75-b726-f4386d2726b0 (old id 467242)
• date added to LUP: 2016-04-01 16:20:37
• date last changed: 2018-11-21 20:40:39