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Testing the sufficiency of research and motor octane number specifications against petrol compositional variations.
Thesis (MEng)--Stellenbosch University, 2021.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2021
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| _version_ | 1867614139072905216 |
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| access_status_str | Open Access |
| author | Van Amstel, C. L. |
| author2 | Haines, R. W. |
| author_browse | Haines, R. W. Van Amstel, C. L. |
| author_facet | Haines, R. W. Van Amstel, C. L. |
| author_sort | Van Amstel, C. L. |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2021. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/123604 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:47:17.083Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/123604 Testing the sufficiency of research and motor octane number specifications against petrol compositional variations. Van Amstel, C. L. Haines, R. W. Floweday, G. Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. Engine testing Knock resistance Motor fuels -- Anti-knock and anti-knock mixtures -- Research Petrol compositional variations. UCTD Octane number Anti-knock compounds Thesis (MEng)--Stellenbosch University, 2021. ENGLISH ABSTRACT: To date, the standardised test methodology and equipment used to measure the autoignition resistance of a fuel, its octane rating, has undergone little change. From this limited change in methodology, the central fuel properties have remained. These properties of a fuel are regarded as descriptors of a fuel’s knock resistance regardless of its composition. This study aimed to test blends of different chemical composition yet matching octane numbers, both research octane number (RON) and motor octane number (MON), in the co-operative fuels research (CFR) engine and comparing their spark timing results in production engines. Since production engines use knock-limited spark advance (KLSA) to determine knock-free engine conditions, the assumption was that the matching octane rated fuels would present some similarities in KLSA results. This would indicate similar resistances to knock for the fuel blends, regardless of engine type. It was decided to use port-fuel injection (PFI) and boosted gasoline direct injection (GDI) engines. These two engines represented different technological classes of production engines, with differences in operating parameters between them as well as the CFR engine. Blends consisted of primary reference fuels (PRFs) and a third sensitivity inducing component for each individual blend from the main molecular classes: aromatic, olefin, ether and oxygenate. In using different component classes, the benefit of measuring matching results would strengthen the project assumption. It would also allow for focussed attention towards a specific class if discrepancies were to be measured. These blends were refined to 95 RON and 85 MON to match and allow for comparison to a standard fuel station 95 unleaded petrol (ULP). These blends were tested and the KLSA results measured were unexpectedly different for both engines. However, upon inspection it was found that the engines varied the air-fuel (AF) ratios and the boost pressure in the GDI differently for each blend. To explain the differences, the influence of these changing engine parameters and their influence on the octane rating of a fuel were determined through testing and estimation from literature. These influences were calculated and presented using the octane index (OI) and Kalghagti K factor. From the blend OI values, the differences between each blend and the 95 ULP base fuel was determined. It was surmised that the differences in the calculated OI values between the blends and the base fuel would explain the respective spark timing differences. However, by comparing the differences in OI to the differences in spark timing data, no clear correlation was evident for either PFI or GDI engine. This indicated that the KLSA results would be different for the different composition blends regardless of similar engine parameters. Thus, proving the hypothesis that fuels of matching RON and MON do not present similarities in KLSA results in production engines. AFRIKAANSE OPSOMMING: Sedert die ontstaan van die binnebrandenjin is dié tegnologie in ‘n toestand van ontwikkeling. Tog het die meet van oktaan in moderne brandstowwe nie tred gehou met die ontewikkeling van die moderne produksie enjin nie. Tot op hede is die standaard toetsmetodiek en -toerusting vir die toets van brandstowwe se weerstand teen hul neiging tot spontane ontbranding, sy oktaanwaarde, onder ontwikkeld. Teen hierdie agtergrond het die sentrale brandstof eiesnakppe voortbestaan. Hierdie bradnstof eienskappe stel dat brandstowwe met ooreenstemmende oktaanwaardes se weerstand tot spontane ontbranding dieselfde is in ‘n binnebrandenjin onafhanklik van sy chemiese samestelling. Hierdie studie is gemik daarop om dit te toets deur brandstowwe met verskillende chemisese samestellings, maar ooreenstemmende oktaan getalle, beide navorsing en motor metode, in die korporatiewe brandstof navorsingenjin te toets. Hierdie brandstowwe word dan ook in moderne produksie-enjins getoets en hul ontstekings periodes word vergelyk. Aangesien die moderne produksie-enjin sy ontsekings periodes vertraag om die spontane ontbranding van die brandstof te vermy, was daar verwag dat die soortgelyke oktaangetalle soortgelyke ontstekings periodes sou voorstel. Dit sou dus aandui dat die weerstand teen spontane onbranding van die brandstowwe dieselfde is, ongeag van enjin tipe. Die enjins waarin die brandstowwe getoets was, was klep-geïntegreerde brandstofinspuiting en aangejaagde direkte brandstofinspuiting. Hierdie enjins was gekies om die verskillende tegnologiese klasse van die moderne produksie-enjin te verteenwoordig, met verskille tussen hul bedryfsparameters asook van die korporatiewe brandstof navorsingsenjin. Vir die meng van die brandstowwe is die primêre verwysings brandstowwe gebruik asook ‘n derde sensitiwiteits bepalende komponent vir elk van die individuele vermengings van die hoof molekulêre klasse: aromaties, olefien, eter en alkohol. Die verskeidenheid van brandstof klasse het ook toegelaat dat ‘n spesifieke klas geteiken kon word indien verskille gewaar was. Die voorgenoemde brandstowwe was gemeng tot dieselfde oktaangetalle as ‘n standaard 95 vulstasie brandstof, met navorsing en motor oktaangetalle van 95 en 85, onderskeidelik. Hierdie vermengings was getoets en die ontstekings periode resultate was verbasend anders gevind vir beide enjins. Na ondersoek is daar gevind dat die lug- tot-brandstof verhouding in albei enjins en aangejaagde lugdruk in die aangejaagde enjin aansienlik verskil het vir elke vermenging tydens die toetse. Om hierdie verskille te verstaan was die invloed van die veranderende enjin toestande en hul uitwerking op die oktaanlesing van die brandstowwe ondersoek. Hierdie bepalings is bereken en voorgestel met die gebruik van die oktaan indeks en die Kalghatgi K factor. Vanaf die vermengings oktaan indeks waardes is die verskille tussen elke mengsel en die 95 oktaan vulstasie brandstof bepaal. Daar was verwag dat die verskille in die bepaalde oktaan indeks waardes tussen die vermengings en die 95 oktaan vulstasie brandstof die verskille in die ontstekings periodes sou kon verduidelik. Alhoewel, deur die verskille te vergelyk was daar gevind dat daar geen onderskeidings opgemerk is nie. Dit is dus bevind dat die ontstekings periode resultate verskillend sou wees vir die mengsels ongeag van soortgelyke enjin toestande. Ten slotte, brandstowwe met soortgelyke oktaangetalle vertoon nie soortgelyke ontstekings periode resultate in produksie- enjins nie. Masters 2021-06-23T15:19:52Z 2021-12-22T14:11:48Z 2021-06-23T15:19:52Z 2021-12-22T14:11:48Z 2021-12 Thesis http://hdl.handle.net/10019.1/123604 en_ZA Stellenbosch University 125 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Engine testing Knock resistance Motor fuels -- Anti-knock and anti-knock mixtures -- Research Petrol compositional variations. UCTD Octane number Anti-knock compounds Van Amstel, C. L. Testing the sufficiency of research and motor octane number specifications against petrol compositional variations. |
| title | Testing the sufficiency of research and motor octane number specifications against petrol compositional variations. |
| title_full | Testing the sufficiency of research and motor octane number specifications against petrol compositional variations. |
| title_fullStr | Testing the sufficiency of research and motor octane number specifications against petrol compositional variations. |
| title_full_unstemmed | Testing the sufficiency of research and motor octane number specifications against petrol compositional variations. |
| title_short | Testing the sufficiency of research and motor octane number specifications against petrol compositional variations. |
| title_sort | testing the sufficiency of research and motor octane number specifications against petrol compositional variations |
| topic | Engine testing Knock resistance Motor fuels -- Anti-knock and anti-knock mixtures -- Research Petrol compositional variations. UCTD Octane number Anti-knock compounds |
| url | http://hdl.handle.net/10019.1/123604 |
| work_keys_str_mv | AT vanamstelcl testingthesufficiencyofresearchandmotoroctanenumberspecificationsagainstpetrolcompositionalvariations |