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Modeling Charge Preparation And Combustion In Diesel Fuel, Ethanol, And Dual-Fuel PCCI Engines

Kokjohn, Sage L.; Splitter, Derek A.; Hanson, Reed M.; Reitz, Rolf D.; Manente, Vittorio LU and Johansson, Bengt LU (2011) In Atomization and Sprays 21(2). p.107-119
Abstract
In this work, multi-dimensional computational fluid dynamics modeling predictions are compared for three different methods of achieving high-efficiency, low NOT, and soot premixed charge compression ignition (PCCI) combustion. The first method is early injection, highly dilute (i.e., low oxygen concentration), diesel fuel PCCI operation. In this method, the oxygen concentration is reduced to extend the ignition delay to allow adequate time for mixing prior to autoignition. The second method is early injection PCCI operation using neat ethanol. In this method, the fuel reactivity is sufficiently low such that PCCI combustion can be achieved without using external dilution. The final method, dual-fuel reactivity controlled compression... (More)
In this work, multi-dimensional computational fluid dynamics modeling predictions are compared for three different methods of achieving high-efficiency, low NOT, and soot premixed charge compression ignition (PCCI) combustion. The first method is early injection, highly dilute (i.e., low oxygen concentration), diesel fuel PCCI operation. In this method, the oxygen concentration is reduced to extend the ignition delay to allow adequate time for mixing prior to autoignition. The second method is early injection PCCI operation using neat ethanol. In this method, the fuel reactivity is sufficiently low such that PCCI combustion can be achieved without using external dilution. The final method, dual-fuel reactivity controlled compression ignition (RCCI) combustion, blends fuels with different ignition qualities in the combustion chamber to tailor the auto-ignition properties of the mixture for the specific operating condition. In this study, RCCI operation was investigated using in-cylinder fuel blending of diesel fuel and gasoline as well as diesel fuel and an E85 blend (i.e., 85% ethanol and 15% gasoline). It was found that the modeling approach used in this work is capable of capturing the bulk combustion characteristics (e.g., cylinder pressure) as well as the details of the injection event (e.g., liquid penetration) and ignition processes. The simulations were shown to provide accurate predictions of the differences in combustion characteristics of diesel fuel, ethanol, and fuel blends (i.e., gasoline + diesel fuel and E85 + diesel fuel). It was found that the ethanol PCCI and dual-fuel (gasoline + diesel fuel and E85 + diesel fuel) RCCI cases have significantly reduced rates of energy release compared to neat diesel fuel PCCI operation. The reduced energy release rates of the ethanol PCCI and dual-fuel RCCI cases may allow these modes of PCCI combustion to achieve higher engine loads than that of neat diesel PCCI. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
engine modeling, thermal efficiency, low-temperature combustion, pollutant emissions reduction
in
Atomization and Sprays
volume
21
issue
2
pages
107 - 119
publisher
Begell House
external identifiers
  • wos:000296219700001
  • scopus:80052377159
ISSN
1936-2684
DOI
10.1615/AtomizSpr.2011002836
language
English
LU publication?
yes
id
9fcfde5c-d773-4c64-9356-5f6881cb4ca1 (old id 2211590)
date added to LUP
2011-11-25 11:30:01
date last changed
2017-08-20 03:09:48
@article{9fcfde5c-d773-4c64-9356-5f6881cb4ca1,
  abstract     = {In this work, multi-dimensional computational fluid dynamics modeling predictions are compared for three different methods of achieving high-efficiency, low NOT, and soot premixed charge compression ignition (PCCI) combustion. The first method is early injection, highly dilute (i.e., low oxygen concentration), diesel fuel PCCI operation. In this method, the oxygen concentration is reduced to extend the ignition delay to allow adequate time for mixing prior to autoignition. The second method is early injection PCCI operation using neat ethanol. In this method, the fuel reactivity is sufficiently low such that PCCI combustion can be achieved without using external dilution. The final method, dual-fuel reactivity controlled compression ignition (RCCI) combustion, blends fuels with different ignition qualities in the combustion chamber to tailor the auto-ignition properties of the mixture for the specific operating condition. In this study, RCCI operation was investigated using in-cylinder fuel blending of diesel fuel and gasoline as well as diesel fuel and an E85 blend (i.e., 85% ethanol and 15% gasoline). It was found that the modeling approach used in this work is capable of capturing the bulk combustion characteristics (e.g., cylinder pressure) as well as the details of the injection event (e.g., liquid penetration) and ignition processes. The simulations were shown to provide accurate predictions of the differences in combustion characteristics of diesel fuel, ethanol, and fuel blends (i.e., gasoline + diesel fuel and E85 + diesel fuel). It was found that the ethanol PCCI and dual-fuel (gasoline + diesel fuel and E85 + diesel fuel) RCCI cases have significantly reduced rates of energy release compared to neat diesel fuel PCCI operation. The reduced energy release rates of the ethanol PCCI and dual-fuel RCCI cases may allow these modes of PCCI combustion to achieve higher engine loads than that of neat diesel PCCI.},
  author       = {Kokjohn, Sage L. and Splitter, Derek A. and Hanson, Reed M. and Reitz, Rolf D. and Manente, Vittorio and Johansson, Bengt},
  issn         = {1936-2684},
  keyword      = {engine modeling,thermal efficiency,low-temperature combustion,pollutant emissions reduction},
  language     = {eng},
  number       = {2},
  pages        = {107--119},
  publisher    = {Begell House},
  series       = {Atomization and Sprays},
  title        = {Modeling Charge Preparation And Combustion In Diesel Fuel, Ethanol, And Dual-Fuel PCCI Engines},
  url          = {http://dx.doi.org/10.1615/AtomizSpr.2011002836},
  volume       = {21},
  year         = {2011},
}