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Optical Investigation on the Combustion Process Differences between Double-Pilot and Closely-Coupled Triple-Pilot Injection Strategies in a LD Diesel Engine

Denny, Michael LU ; Matamis, Alexios LU ; Wang, Zhenkan LU ; Persson, Håkan LU ; Tunestal, Per LU ; Richter, Mattias LU and Andersson, A. Ivind LU (2019) SAE 2019 International Powertrains, Fuels and Lubricants Meeting, FFL 2019 In SAE Technical Papers 2019-January.
Abstract

The combustion processes of three injection strategies in a light-duty (LD) diesel engine at a medium load point are captured with a high speed video camera. A double-pilot/main/single-post injection strategy representative of a LD Euro 6 calibration is considered as the reference. There is a modest temporal spacing (dwell) after the first pilot (P1) and second pilot (P2). A second strategy, "A," adds a third pilot (P3). The dwell after both P2 and P3 are several times shorter than in the reference strategy. A third strategy, "B," further reduces all dwells. Each injection has its own associated local peak in the heat release rate (HRR) following some ignition delay. Between these peaks lie local minima, or dips. In all three cases, the... (More)

The combustion processes of three injection strategies in a light-duty (LD) diesel engine at a medium load point are captured with a high speed video camera. A double-pilot/main/single-post injection strategy representative of a LD Euro 6 calibration is considered as the reference. There is a modest temporal spacing (dwell) after the first pilot (P1) and second pilot (P2). A second strategy, "A," adds a third pilot (P3). The dwell after both P2 and P3 are several times shorter than in the reference strategy. A third strategy, "B," further reduces all dwells. Each injection has its own associated local peak in the heat release rate (HRR) following some ignition delay. Between these peaks lie local minima, or dips. In all three cases, the fuel from P1 combusts as a propagating premixed flame. For all strategies, the ignition of P2 primarily occurs at its interface with the existing combustion regions. Extinguishing of the prevailing combustion by the fuel jets of later injections is noted in all strategies. This phenomenon is confirmed by comparing the timing of each fuel injection with the dips in the HRR and spatial luminescence over time. These dips after each injection are larger than would be expected by the cooling effect of the injected fuel alone. Furthermore, not all dips in the HRR are the result of this extinguishing, and it would not have been possible to determine if the dips are due to this extinguishing or a simple exhaustion of available fuel without this optical investigation. Even if the precise hydraulic injection timing can be known, knowledge of the spatial relationship of the injected fuel and prevailing combustion is necessary.

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Please use this url to cite or link to this publication:
author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
host publication
International Powertrains, Fuels & Lubricants Meeting
series title
SAE Technical Papers
volume
2019-January
conference name
SAE 2019 International Powertrains, Fuels and Lubricants Meeting, FFL 2019
conference location
San Antonio, United States
conference dates
2019-01-22 - 2019-01-24
external identifiers
  • scopus:85060513029
ISSN
0148-7191
DOI
10.4271/2019-01-0022
language
English
LU publication?
yes
id
39ac71dd-ed90-487f-89d0-6fa39c131985
date added to LUP
2019-02-05 14:10:04
date last changed
2019-02-27 05:12:25
@inproceedings{39ac71dd-ed90-487f-89d0-6fa39c131985,
  abstract     = {<p>The combustion processes of three injection strategies in a light-duty (LD) diesel engine at a medium load point are captured with a high speed video camera. A double-pilot/main/single-post injection strategy representative of a LD Euro 6 calibration is considered as the reference. There is a modest temporal spacing (dwell) after the first pilot (P1) and second pilot (P2). A second strategy, "A," adds a third pilot (P3). The dwell after both P2 and P3 are several times shorter than in the reference strategy. A third strategy, "B," further reduces all dwells. Each injection has its own associated local peak in the heat release rate (HRR) following some ignition delay. Between these peaks lie local minima, or dips. In all three cases, the fuel from P1 combusts as a propagating premixed flame. For all strategies, the ignition of P2 primarily occurs at its interface with the existing combustion regions. Extinguishing of the prevailing combustion by the fuel jets of later injections is noted in all strategies. This phenomenon is confirmed by comparing the timing of each fuel injection with the dips in the HRR and spatial luminescence over time. These dips after each injection are larger than would be expected by the cooling effect of the injected fuel alone. Furthermore, not all dips in the HRR are the result of this extinguishing, and it would not have been possible to determine if the dips are due to this extinguishing or a simple exhaustion of available fuel without this optical investigation. Even if the precise hydraulic injection timing can be known, knowledge of the spatial relationship of the injected fuel and prevailing combustion is necessary.</p>},
  author       = {Denny, Michael and Matamis, Alexios and Wang, Zhenkan and Persson, Håkan and Tunestal, Per and Richter, Mattias and Andersson, A. Ivind},
  booktitle    = {SAE Technical Papers},
  issn         = {0148-7191},
  language     = {eng},
  location     = {San Antonio, United States},
  month        = {01},
  title        = {Optical Investigation on the Combustion Process Differences between Double-Pilot and Closely-Coupled Triple-Pilot Injection Strategies in a LD Diesel Engine},
  url          = {http://dx.doi.org/10.4271/2019-01-0022},
  volume       = {2019-January},
  year         = {2019},
}