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The Usefulness of Negative Valve Overlap for Gasoline Partially Premixed Combustion, PPC

Borgqvist, Patrick LU ; Tunér, Martin LU ; Mello, Augusto; Tunestål, Per LU and Johansson, Bengt LU (2012) SAE 2012 International Powertrains, Fuels & Lubricants Meeting In SAE Technical Paper Series
Abstract
Partially premixed combustion has the potential of high efficiency and simultaneous low soot and NOx emissions. Running the engine in PPC mode with high octane number fuels has the advantage of a longer premix period of fuel and air which reduces soot emissions, even at higher loads. The problem is the ignitability at low load and idle operating conditions.



The objective is to investigate the usefulness of negative valve overlap on a light duty diesel engine running with gasoline partially premixed combustion at low load operating conditions. The idea is to use negative valve overlap to trap hot residual gases to elevate the global in-cylinder temperature to promote auto-ignition of the high octane number fuel. This is... (More)
Partially premixed combustion has the potential of high efficiency and simultaneous low soot and NOx emissions. Running the engine in PPC mode with high octane number fuels has the advantage of a longer premix period of fuel and air which reduces soot emissions, even at higher loads. The problem is the ignitability at low load and idle operating conditions.



The objective is to investigate the usefulness of negative valve overlap on a light duty diesel engine running with gasoline partially premixed combustion at low load operating conditions. The idea is to use negative valve overlap to trap hot residual gases to elevate the global in-cylinder temperature to promote auto-ignition of the high octane number fuel. This is of practical interest at low engine speed and load operating conditions because it can be assumed that the available boost is limited. The problem with NVO at low load operating conditions is that the exhaust gas temperature is low. While an increase of NVO potentially increases the in-cylinder temperature at intake valve closing, increasing NVO also increases the EGR fraction which lowers the global in-cylinder temperature. The question is to what extent NVO can be used to extend the low load operating region. Investigations on the effect of the glow plug are also included.



The experimental engine is modeled with the engine simulation tool AVL Boost to retrieve information about trapped residual gas fraction and in-cylinder temperature with varying NVO and load at low engine speed and load operating conditions. Measured experimental data is used as input to the engine simulation model at all operating conditions. Measured model inputs include valve lift curves, in-cylinder pressure trace and calculated heat-release profiles. (Less)
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
keywords
Internal Combustion Engines, Partially Premixed Combustion, Negative Valve Overlap
in
SAE Technical Paper Series
publisher
Society of Automotive Engineers
conference name
SAE 2012 International Powertrains, Fuels & Lubricants Meeting
external identifiers
  • other:2012-01-1578
  • scopus:84881194076
ISSN
0148-7191
DOI
10.4271/2012-01-1578
language
English
LU publication?
yes
id
13c51908-bded-435f-a3a3-2acb0478249e (old id 4318422)
alternative location
http://papers.sae.org/2012-01-1578/
date added to LUP
2014-02-24 14:11:35
date last changed
2017-06-11 04:12:10
@inproceedings{13c51908-bded-435f-a3a3-2acb0478249e,
  abstract     = {Partially premixed combustion has the potential of high efficiency and simultaneous low soot and NOx emissions. Running the engine in PPC mode with high octane number fuels has the advantage of a longer premix period of fuel and air which reduces soot emissions, even at higher loads. The problem is the ignitability at low load and idle operating conditions.<br/><br>
<br/><br>
The objective is to investigate the usefulness of negative valve overlap on a light duty diesel engine running with gasoline partially premixed combustion at low load operating conditions. The idea is to use negative valve overlap to trap hot residual gases to elevate the global in-cylinder temperature to promote auto-ignition of the high octane number fuel. This is of practical interest at low engine speed and load operating conditions because it can be assumed that the available boost is limited. The problem with NVO at low load operating conditions is that the exhaust gas temperature is low. While an increase of NVO potentially increases the in-cylinder temperature at intake valve closing, increasing NVO also increases the EGR fraction which lowers the global in-cylinder temperature. The question is to what extent NVO can be used to extend the low load operating region. Investigations on the effect of the glow plug are also included.<br/><br>
<br/><br>
The experimental engine is modeled with the engine simulation tool AVL Boost to retrieve information about trapped residual gas fraction and in-cylinder temperature with varying NVO and load at low engine speed and load operating conditions. Measured experimental data is used as input to the engine simulation model at all operating conditions. Measured model inputs include valve lift curves, in-cylinder pressure trace and calculated heat-release profiles.},
  author       = {Borgqvist, Patrick and Tunér, Martin and Mello, Augusto and Tunestål, Per and Johansson, Bengt},
  booktitle    = {SAE Technical Paper Series},
  issn         = {0148-7191},
  keyword      = {Internal Combustion Engines,Partially Premixed Combustion,Negative Valve Overlap},
  language     = {eng},
  publisher    = {Society of Automotive Engineers},
  title        = {The Usefulness of Negative Valve Overlap for Gasoline Partially Premixed Combustion, PPC},
  url          = {http://dx.doi.org/10.4271/2012-01-1578},
  year         = {2012},
}