Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: With worldwide emissions standards becoming more stringent over the
last decade, the South African market seems set to follow suit. Older technology
engines are however unable to attain these stringent standards and will require
cleaner burning fuels. Biofuels like biodiesel and bioethanol-diesel blends are an
attractive option as a result of their inherently oxygenated nature and renewable,
low carbon footprint. Oxygenated fuels have been found to lower particulate and
soot emissions without any significant increase in NOx, thus alleviating the usual
particulate-NOx trade-off.
In this study an existing diesel engine test facility has been upgraded to include
emission equipment, and a low cost pressure indicating system. Fuel-to-fuel
comparative testing was done with pump diesel and splash blended fuels
consisting of pump diesel blended with varying amounts of ethanol and also
biodiesel without including any cetane enhancing or blend stability additives.
Emission analysis of the blended fuels showed a marked reduction in soot
emission with little to no increase in NOx emission for all oxygenated fuels. This
type of soot reduction without NOx increase is difficult to obtain through any
other method. Blend stability was however a problem with the 15% ethanol-diesel
blends. / AFRIKAANSE OPSOMMING: Met wêreldwye uitlaatgas standaarde wat al hoe strenger geword het oor
die laaste dekade, lyk dit asof dit net ‘n kwessie van tyd is voor Suid-Afrika
dieselfde roete volg. Ouer tegnologie binnebrandenjins kan egter nie hierdie
streng standaarde handhaaf nie en sal dus vereis dat die brandstof skoner brand.
Biobrandstowwe, soos biodiesel en bio-etanol-diesel mengsels, blyk ‘n
aantreklike opsie te wees vanweë hul natuurlike inhoud van suurstof en as
hernubare hulpbron. Wanneer suurstof houdende brandstowwe soos hierdie
verbrand word, word daar gevind dat daar ‘n daadwerklike afname in rook uitlaat
is sonder enige merkbare toename in NOx uitlaatgasse. Dit is teenstrydig met die
gewoonlike wisselwerking wat daar tussen hierdie twee uitlaatgas produkte is.
In hierdie studie word die bestaande diesel enjin toetssel opgegradeer om
uitlaatgas analiese toerusting asook ‘n lae-koste silinderdruk meettoestel te bevat.
Brandstof-tot-brandstof vergelykings toetse word gedoen met gewone diesel
asook toets diesel wat gemengde konsentrasies biodiesel of bio-etanol bevat. Die
toets diesel bevat egter geen aanvullings om mengselstabiliteit of cetaan te
verbeter nie. Toetsresultate toon dat daar merkbare vermindering in rook uitlaat is
met min tot geen toename in NOx. Hierdie tipe van resultaat met produkte van
ontbranding is moeilik om op enige ander manier te bewerkstellig. Daar word ook
gevind dat diesel met 15 % bio-etanol nie ‘n stabiele mengsel is nie en dat fase
skeiding plaasvind.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/97075 |
| Date | 03 1900 |
| Creators | Blom, Cornelius Janse |
| Contributors | Haines, R. W., Stellenbosch University. Faculty of Engineering. Dept of Mechanical and Mechatronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 128 pages : illustrations |
| Rights | Stellenbosch University |
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