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Combustion characteristics of gasoline DICI engine in the transition from HCCI to PPC : Experiment and numerical analysis

Xu, Leilei LU ; Bai, Xue Song LU ; Li, Changle LU ; Tunestål, Per LU ; Tunér, Martin LU and Lu, Xingcai (2019) In Energy 185. p.922-937
Abstract

Both numerical simulations and experiments were conducted in a heavy-duty DICI engine, with PRF81 as a gasoline surrogate, to investigate how the fuel stratification, auto-ignition and combustion are affected by the start of injection (SOI). The intake air temperature was adjusted to keep the combustion phasing constant when the SOI was swept from −100 to −20 oCA ATDC, covering different regimes of combustion, from HCCI to PPC. It is found that in the HCCI regime the combustion process is less sensitive to the variation of SOI since the fuel/air mixture is fairly homogeneous. The fuel/air mixture is under fuel-lean condition and the required intake temperature for a constant CA50 is the highest. In the PPC regime there is an optimal SOI... (More)

Both numerical simulations and experiments were conducted in a heavy-duty DICI engine, with PRF81 as a gasoline surrogate, to investigate how the fuel stratification, auto-ignition and combustion are affected by the start of injection (SOI). The intake air temperature was adjusted to keep the combustion phasing constant when the SOI was swept from −100 to −20 oCA ATDC, covering different regimes of combustion, from HCCI to PPC. It is found that in the HCCI regime the combustion process is less sensitive to the variation of SOI since the fuel/air mixture is fairly homogeneous. The fuel/air mixture is under fuel-lean condition and the required intake temperature for a constant CA50 is the highest. In the PPC regime there is an optimal SOI window, within which the required intake temperature is the lowest to maintain a constant CA50 and the engine thermal efficiency is the highest. The optimal operation window starts at the SOI when all fuel is injected into the piston bowl and ends when the fuel injection is towards the bottom wall of the piston bowl, which results in a high heat transfer losses. The SOI window for optimal engine operation is expected to be fuel injector and piston bowl geometry dependent. During the transition regime, the fuel is injected towards the piston head in the squish region. The combustion process is highly sensitive to SOI due to the high sensitivity of fuel distribution in the cylinder to SOI. The engine thermal efficiency is the lowest due to the incomplete oxidation of fuel in the squish region.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Combustion phasing, Fuel stratification, Intake temperature, Partially premixed combustion (PPC), Start of injection (SOI), Transition
in
Energy
volume
185
pages
16 pages
publisher
Elsevier
external identifiers
  • scopus:85069695361
ISSN
0360-5442
DOI
10.1016/j.energy.2019.07.082
language
English
LU publication?
yes
id
90be2aac-4281-4e07-a33d-69c781474720
date added to LUP
2019-08-02 11:44:50
date last changed
2019-08-28 04:57:38
@article{90be2aac-4281-4e07-a33d-69c781474720,
  abstract     = {<p>Both numerical simulations and experiments were conducted in a heavy-duty DICI engine, with PRF81 as a gasoline surrogate, to investigate how the fuel stratification, auto-ignition and combustion are affected by the start of injection (SOI). The intake air temperature was adjusted to keep the combustion phasing constant when the SOI was swept from −100 to −20 oCA ATDC, covering different regimes of combustion, from HCCI to PPC. It is found that in the HCCI regime the combustion process is less sensitive to the variation of SOI since the fuel/air mixture is fairly homogeneous. The fuel/air mixture is under fuel-lean condition and the required intake temperature for a constant CA50 is the highest. In the PPC regime there is an optimal SOI window, within which the required intake temperature is the lowest to maintain a constant CA50 and the engine thermal efficiency is the highest. The optimal operation window starts at the SOI when all fuel is injected into the piston bowl and ends when the fuel injection is towards the bottom wall of the piston bowl, which results in a high heat transfer losses. The SOI window for optimal engine operation is expected to be fuel injector and piston bowl geometry dependent. During the transition regime, the fuel is injected towards the piston head in the squish region. The combustion process is highly sensitive to SOI due to the high sensitivity of fuel distribution in the cylinder to SOI. The engine thermal efficiency is the lowest due to the incomplete oxidation of fuel in the squish region.</p>},
  author       = {Xu, Leilei and Bai, Xue Song and Li, Changle and Tunestål, Per and Tunér, Martin and Lu, Xingcai},
  issn         = {0360-5442},
  keyword      = {Combustion phasing,Fuel stratification,Intake temperature,Partially premixed combustion (PPC),Start of injection (SOI),Transition},
  language     = {eng},
  month        = {10},
  pages        = {922--937},
  publisher    = {Elsevier},
  series       = {Energy},
  title        = {Combustion characteristics of gasoline DICI engine in the transition from HCCI to PPC : Experiment and numerical analysis},
  url          = {http://dx.doi.org/10.1016/j.energy.2019.07.082},
  volume       = {185},
  year         = {2019},
}