dc.contributor.advisor |
Raine, Robert R. |
en |
dc.contributor.advisor |
Blanchard, George W. |
en |
dc.contributor.author |
Longdill, Simon James |
en |
dc.date.accessioned |
2020-07-08T04:50:13Z |
en |
dc.date.available |
2020-07-08T04:50:13Z |
en |
dc.date.issued |
2001 |
en |
dc.identifier.uri |
http://hdl.handle.net/2292/52005 |
en |
dc.description |
Full text is available to authenticated members of The University of Auckland only. |
en |
dc.description.abstract |
The primary focus of this work was the application of optical combustion measurements to two- stroke engine combustion analysis. This objective arose from the desire to develop a method to measure the real-time air-fuel ratio of engine operation. A number of techniques were considered, but the optical method appeared most promising and was therefore selected for further study.
Combustion light emission was measured at two wavelengths, 430nm and 515nm. These wavelengths correspond closely to the chemiluminescent light emission bands of the CH and C2 radicals respectively. The effect of air-fuel ratio on the combustion light emission at these wavelengths was initially studied using a steady-flow burner, operating on a premixed gasoline- air mixture. The relative intensity of light emitted at these two wavelengths was found to be directly related to air-fuel ratio over a range from 9:1 to 19:1 by mass, a much wider range than typically employed in engines. The lubricating oil pre-mixed in common two-stroke engine fuel was not found to significantly affect the measured light emission from this burner.
The flame light emission measurement system was then installed on a high performance two- stroke engine. The build-up of combustion deposits on the optical surfaces of the window inside the engine reduced the optical transmission properties of the window to a large degree, although it reached a constant level after a period of steady state operation. The contamination build up also markedly affected the angular response of the window to light emission from different areas
within the combustion chamber.
Significant differences were observed between the light emission characteristics from the steady- flow burner and engine. This is attributed to the detection of both flame front and burned gas zone light emission from the engine. The flame front emission varied significantly with air-fuel ratio, while the light emission from the burned gas zone depended on the temperature of the burned gases and was affected by load, ignition timing and air-fuel ratio. Correlations were observed between the position of 50% mass fraction burned and 50% light emitted at 430nm over a range of speeds and loads, due to the significant burned gas zone light emission at this wavelength. This relationship showed promise for use in control of ignition timing, although was detrimentally influenced by chemiluminescent light emission at Iow load operation conditions. The influences of burned zone light emission on the accurate estimation of air-fuel ratio were reduced by determining the relative intensity of emission at each wavelength 25 degrees after ignition. Over the normal range of air-fuel ratios, tests showed the air-fuel ratio can be measured to an accuracy of±0.5 which is sufficient for use in fuelling control systems. |
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dc.publisher |
ResearchSpace@Auckland |
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dc.relation.ispartof |
PhD Thesis - University of Auckland |
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dc.relation.isreferencedby |
UoA99113055314002091 |
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dc.rights |
Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. |
en |
dc.rights |
Restricted Item. Full text is available to authenticated members of The University of Auckland only. |
en |
dc.rights.uri |
https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm |
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dc.title |
Optical measurement of two-stroke engine combustion |
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dc.type |
Thesis |
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thesis.degree.discipline |
Mechanical Engineering |
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thesis.degree.grantor |
The University of Auckland |
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thesis.degree.level |
Doctoral |
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thesis.degree.name |
PhD |
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dc.rights.holder |
Copyright: The author |
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dc.identifier.wikidata |
Q112856872 |
|