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The HCCI Fuel Number - Measuring and Describing Auto-ignition for HCCI Combustion Engines

Truedsson, Ida LU (2014)
Abstract (Swedish)
Popular Abstract in Swedish

Att mäta och beskriva självantändning vid förblandad kompressionsantändning (HCCI)

HCCI-förbränning går ut på att luft och bränsle blandas, och komprimeras i en kolvmotor tills blandningen självantänder. På grund av den snabba förbränningen med det här konceptet förloras mindre värmeenergi, och verkningsgraden blir därför högre än för vanliga bensin- och dieselmotorer.

Genom att öka verkningsgraden kan vi resa en viss sträcka, eller transportera en viss mängd gods, med lägre bränsleförbrukning. Detta leder till lägre koldioxidutsläpp och därför en mindre påverkan på den globala uppvärmningen. Nya typer av förbränningsmotorer kan också underlätta vid användning av biobränslen,... (More)
Popular Abstract in Swedish

Att mäta och beskriva självantändning vid förblandad kompressionsantändning (HCCI)

HCCI-förbränning går ut på att luft och bränsle blandas, och komprimeras i en kolvmotor tills blandningen självantänder. På grund av den snabba förbränningen med det här konceptet förloras mindre värmeenergi, och verkningsgraden blir därför högre än för vanliga bensin- och dieselmotorer.

Genom att öka verkningsgraden kan vi resa en viss sträcka, eller transportera en viss mängd gods, med lägre bränsleförbrukning. Detta leder till lägre koldioxidutsläpp och därför en mindre påverkan på den globala uppvärmningen. Nya typer av förbränningsmotorer kan också underlätta vid användning av biobränslen, vilket både kan leda till vidare minskning av koldioxidutsläpp och till att minska vårt oljeberoende.

I det här arbetet presenteras en nyutvecklad metod för att mäta hur lätt ett bränsle självantänder vid denna typ av kompressionsantändning.

Arbetet gick ut på att köra en motor med variabelt kompressionsförhållande, vilket betyder att motorn under arbete kan ändras genom att cylinderhuvud och kolv förskjuts relativt varandra. Detta gör att bränslen som självantänder olika lätt kan användas och studeras. Så kallade referensbränslen testades först. Dessa består av två olika typer av kolväten, ett som självantänder enkelt och ett som har högre motstånd mot självantändning. Andra typer av bränslen jämfördes senare med dessa referensbränslen. Det kompressionsförhållande som krävdes för att förbränningen skulle ske vid övre dödläget (när trycket är som högst i cylindern) noterades, och detta värde översattes till ett HCCI-tal för varje bränsle. För att förstå den vetenskapliga bakgrunden studerades även förreaktioner i förbränningen, och vi beräknade även temperaturerna vid vilka de olika bränslena antändes.

För att kunna praktiskt använda moderna koncept för lågtemperaturförbränning måste vi veta hur ett bränsle beter sig. Denna nyutvecklade metod mäter detta på ett enkelt vis. (Less)
Abstract
HCCI is an advanced combustion concept, using premixed fuel and air with a diluted charge. This is thermodynamically favorable, leading to high efficiency and therefore lower CO2 emissions. The well-premixed and diluted fuel charge gives lower cylinder temperatures than conventional diesel compression ignition and spark ignited gasoline combustion, resulting in low engine out emissions of both nitrogen oxides and soot.

To be able to optimize and use the advanced combustion concepts in commercial engines, knowledge of fuel behavior is needed, and a way to describe it. This thesis work provides detailed information about HCCI auto-ignition by studying parameters such as low temperature heat release and auto-ignition temperatures.... (More)
HCCI is an advanced combustion concept, using premixed fuel and air with a diluted charge. This is thermodynamically favorable, leading to high efficiency and therefore lower CO2 emissions. The well-premixed and diluted fuel charge gives lower cylinder temperatures than conventional diesel compression ignition and spark ignited gasoline combustion, resulting in low engine out emissions of both nitrogen oxides and soot.

To be able to optimize and use the advanced combustion concepts in commercial engines, knowledge of fuel behavior is needed, and a way to describe it. This thesis work provides detailed information about HCCI auto-ignition by studying parameters such as low temperature heat release and auto-ignition temperatures.

An HCCI Fuel Number is presented, developed with the purpose to describe fuel performance. By comparing fuels such as full distillate gasolines or biofuels to the required compression ratio for auto-ignition for reference fuels, a measure on HCCI fuel performance is gained. This fuel number was shown to correlate well with pre-reactions in the fuels.

The thesis work is based on CFR engine experiments, studying over 40 different reference fuels consisting of blends of n-heptane, iso-octane, toluene, and ethanol, which are model surrogates for gasoline. In addition, 21 different full distillate gasoline fuels prepared from refinery feedstocks, some with addition of single components, were tested as well. Five different inlet air temperatures ranging from 50°C to 150°C were used to achieve different temperature-pressure histories, and the compression ratio was changed accordingly to keep a constant combustion phasing, CA50, of 3±1° after TDC. The main parts of the experiments were carried out in lean operation with a constant equivalence ratio of 0.33 and with an engine speed of 600 rpm. Additional experiments were performed at higher engine speeds.

Studied fuel effects include low temperature heat release quenching effects, were ethanol was found to quench low temperature heat release at all conditions, and toluene had an in comparison very weak effect on these pre-reactions.

All conditions and fuels with extensive low temperature heat release showed similar auto-ignition temperatures. When LTHR diminished, either due to fuel quenching from ethanol or toluene, or when the inlet air temperature was increased, the auto-ignition temperature was increased. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Hagen, Christopher, Oregon State University, USA
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Fuel, Combustion Engines, HCCI, Auto-ignition
pages
186 pages
publisher
Tryckeriet i E-huset, Lunds universitet
defense location
Lecture hall M:A, M-building, Ole Römers väg 1, Lund University Faculty of Engineering
defense date
2014-04-25 10:00
ISSN
0282-1990
ISBN
978-91-7473-949-7 (print)
978-91-7473-950-3
language
English
LU publication?
yes
id
7346f572-3483-40df-9341-5659e2e086ab (old id 4378685)
date added to LUP
2014-04-04 12:19:42
date last changed
2016-09-19 08:44:49
@phdthesis{7346f572-3483-40df-9341-5659e2e086ab,
  abstract     = {HCCI is an advanced combustion concept, using premixed fuel and air with a diluted charge. This is thermodynamically favorable, leading to high efficiency and therefore lower CO2 emissions. The well-premixed and diluted fuel charge gives lower cylinder temperatures than conventional diesel compression ignition and spark ignited gasoline combustion, resulting in low engine out emissions of both nitrogen oxides and soot.<br/><br>
To be able to optimize and use the advanced combustion concepts in commercial engines, knowledge of fuel behavior is needed, and a way to describe it. This thesis work provides detailed information about HCCI auto-ignition by studying parameters such as low temperature heat release and auto-ignition temperatures. <br/><br>
An HCCI Fuel Number is presented, developed with the purpose to describe fuel performance. By comparing fuels such as full distillate gasolines or biofuels to the required compression ratio for auto-ignition for reference fuels, a measure on HCCI fuel performance is gained. This fuel number was shown to correlate well with pre-reactions in the fuels.<br/><br>
The thesis work is based on CFR engine experiments, studying over 40 different reference fuels consisting of blends of n-heptane, iso-octane, toluene, and ethanol, which are model surrogates for gasoline. In addition, 21 different full distillate gasoline fuels prepared from refinery feedstocks, some with addition of single components, were tested as well. Five different inlet air temperatures ranging from 50°C to 150°C were used to achieve different temperature-pressure histories, and the compression ratio was changed accordingly to keep a constant combustion phasing, CA50, of 3±1° after TDC. The main parts of the experiments were carried out in lean operation with a constant equivalence ratio of 0.33 and with an engine speed of 600 rpm. Additional experiments were performed at higher engine speeds.<br/><br>
Studied fuel effects include low temperature heat release quenching effects, were ethanol was found to quench low temperature heat release at all conditions, and toluene had an in comparison very weak effect on these pre-reactions.<br/><br>
All conditions and fuels with extensive low temperature heat release showed similar auto-ignition temperatures. When LTHR diminished, either due to fuel quenching from ethanol or toluene, or when the inlet air temperature was increased, the auto-ignition temperature was increased.},
  author       = {Truedsson, Ida},
  isbn         = {978-91-7473-949-7 (print)},
  issn         = {0282-1990},
  keyword      = {Fuel,Combustion Engines,HCCI,Auto-ignition},
  language     = {eng},
  pages        = {186},
  publisher    = {Tryckeriet i E-huset, Lunds universitet},
  school       = {Lund University},
  title        = {The HCCI Fuel Number - Measuring and Describing Auto-ignition for HCCI Combustion Engines},
  year         = {2014},
}