Investigations of the Influence of Mixture Preparation on Cyclic Variations in a SI-Engine, Using Laser Induced Fluorescence
(1995) SAE International Congress and Exposition, 1995- Abstract
- To study the effect of different injection timings on the charge inhomogeneity, planar laser-induced fluorescence (PLIF) was applied to an operating engine. Quantitative images of the fuel distribution within the engine were obtained. Since the fuel used, iso-octane, does not fluoresce, a dopant was required. Three pentanone was found to have vapor pressure characteristics similar to those of iso-octane as well as low absorption and suitable spectral properties.
A worst case estimation of the total accuracy from the PLIF images gives a maximum error of 0.03 in equivalence ratio. The results show that an early injection timing gives a higher degree of charge inhomogeneity close to the spark plug. It is also known that... (More) - To study the effect of different injection timings on the charge inhomogeneity, planar laser-induced fluorescence (PLIF) was applied to an operating engine. Quantitative images of the fuel distribution within the engine were obtained. Since the fuel used, iso-octane, does not fluoresce, a dopant was required. Three pentanone was found to have vapor pressure characteristics similar to those of iso-octane as well as low absorption and suitable spectral properties.
A worst case estimation of the total accuracy from the PLIF images gives a maximum error of 0.03 in equivalence ratio. The results show that an early injection timing gives a higher degree of charge inhomogeneity close to the spark plug. It is also known that charge inhomogeneity gives a more unstable engine operation. A correlation was noted between the combustion on a cycle to cycle basis and the average fuel concentration within a circular area close to the spark plug center. The correlation coefficient when a second order polynomial was fitted reached a value of mA0.8 when the engine operated with a high degree of inhomogeneity. The highest correlation coefficient between the duration of 0-0.5% heat released and the average fuel concentration was obtained within a radius of approximately 5-10 mm from the spark plug. When the standard disc-shaped combustion chamber was replaced with a turbulence generating geometry, the inhomogeneity of the charge became very low, independent of injection timing. No cycle to cycle correlations between fuel/air equivalence ratio and combustion were then noted. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/574944
- author
- Johansson, Bengt LU ; Neij, Hans ; Aldén, Marcus LU and Juhlin, Greger
- organization
- publishing date
- 1995
- type
- Chapter in Book/Report/Conference proceeding
- publication status
- published
- subject
- keywords
- Mixture Preparation, LIF, Laser Induced Fluorescence, Cycle-Cycle Variation
- host publication
- SAE Technical Paper Series
- publisher
- Society of Automotive Engineers
- conference name
- SAE International Congress and Exposition, 1995
- conference location
- Detroit Michigan, United States
- conference dates
- 1995-02-27 - 1995-03-02
- external identifiers
-
- scopus:85072429942
- ISSN
- 0148-7191
- language
- English
- LU publication?
- yes
- id
- c5041d80-ccce-4f44-a460-16ce130b75b2 (old id 574944)
- date added to LUP
- 2016-04-01 16:07:48
- date last changed
- 2021-01-03 06:43:37
@inproceedings{c5041d80-ccce-4f44-a460-16ce130b75b2, abstract = {{To study the effect of different injection timings on the charge inhomogeneity, planar laser-induced fluorescence (PLIF) was applied to an operating engine. Quantitative images of the fuel distribution within the engine were obtained. Since the fuel used, iso-octane, does not fluoresce, a dopant was required. Three pentanone was found to have vapor pressure characteristics similar to those of iso-octane as well as low absorption and suitable spectral properties.<br/><br> <br/><br> A worst case estimation of the total accuracy from the PLIF images gives a maximum error of 0.03 in equivalence ratio. The results show that an early injection timing gives a higher degree of charge inhomogeneity close to the spark plug. It is also known that charge inhomogeneity gives a more unstable engine operation. A correlation was noted between the combustion on a cycle to cycle basis and the average fuel concentration within a circular area close to the spark plug center. The correlation coefficient when a second order polynomial was fitted reached a value of mA0.8 when the engine operated with a high degree of inhomogeneity. The highest correlation coefficient between the duration of 0-0.5% heat released and the average fuel concentration was obtained within a radius of approximately 5-10 mm from the spark plug. When the standard disc-shaped combustion chamber was replaced with a turbulence generating geometry, the inhomogeneity of the charge became very low, independent of injection timing. No cycle to cycle correlations between fuel/air equivalence ratio and combustion were then noted.}}, author = {{Johansson, Bengt and Neij, Hans and Aldén, Marcus and Juhlin, Greger}}, booktitle = {{SAE Technical Paper Series}}, issn = {{0148-7191}}, keywords = {{Mixture Preparation; LIF; Laser Induced Fluorescence; Cycle-Cycle Variation}}, language = {{eng}}, publisher = {{Society of Automotive Engineers}}, title = {{Investigations of the Influence of Mixture Preparation on Cyclic Variations in a SI-Engine, Using Laser Induced Fluorescence}}, url = {{https://lup.lub.lu.se/search/files/4576736/574946.pdf}}, year = {{1995}}, }