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A Novel Model for Computing the Trapping Efficiency and Residual Gas Fraction Validated with an Innovative Technique for Measuring the Trapping Efficiency

Manente, Vittorio LU ; Tunestål, Per LU and Johansson, Bengt LU (2008) Small Engine Technology Conference & Exposition, 2008 In SAE Technical Paper Series 2008-32-0003.
Abstract
The paper describes a novel method for calculating the residual gas fraction and the trapping efficiency in a 2 stroke engine. Assuming one dimensional compressible flow through the inlet and exhaust ports, the method estimates the instantaneous mass flowing in and out from the combustion chamber; later the residual gas fraction and trapping efficiency are estimated combining together the perfect displacement and perfect mixing scavenging models. It is assumed that when the intake port opens, the fresh mixture is pushing out the burned charge without any mixing and after a multiple of the time needed for the largest eddy to perform one rotation, the two gasses are instantly mixed up together and expelled. The result is a very simple... (More)
The paper describes a novel method for calculating the residual gas fraction and the trapping efficiency in a 2 stroke engine. Assuming one dimensional compressible flow through the inlet and exhaust ports, the method estimates the instantaneous mass flowing in and out from the combustion chamber; later the residual gas fraction and trapping efficiency are estimated combining together the perfect displacement and perfect mixing scavenging models. It is assumed that when the intake port opens, the fresh mixture is pushing out the burned charge without any mixing and after a multiple of the time needed for the largest eddy to perform one rotation, the two gasses are instantly mixed up together and expelled. The result is a very simple algorithm that does not require much computational time and is able to estimate with high level of precision the trapping efficiency and the residual gas fraction in 2 stroke engines. The tuning and the validation of this algorithm are performed by measuring the trapping efficiency. These measurements are conducted with an innovative technique which consists in measuring the inlet and exhaust temperature, and calculation of the blow down temperature from the pressure trace. The model was tested using a mini high speed 2 stroke HCCI engine fuelled with diethyl ether between 10,800 and 19,000 [rpm]. (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, Two-Stroke
in
SAE Technical Paper Series
volume
2008-32-0003
publisher
Society of Automotive Engineers
conference name
Small Engine Technology Conference & Exposition, 2008
external identifiers
  • scopus:85028870978
ISSN
0148-7191
DOI
10.4271/2008-32-0003
language
English
LU publication?
yes
id
03f89f9c-c5c3-46ce-a859-802fafa22f24 (old id 1395929)
alternative location
http://papers.sae.org/2008-32-0003/
date added to LUP
2014-02-24 13:31:28
date last changed
2017-10-01 04:02:27
@inproceedings{03f89f9c-c5c3-46ce-a859-802fafa22f24,
  abstract     = {The paper describes a novel method for calculating the residual gas fraction and the trapping efficiency in a 2 stroke engine. Assuming one dimensional compressible flow through the inlet and exhaust ports, the method estimates the instantaneous mass flowing in and out from the combustion chamber; later the residual gas fraction and trapping efficiency are estimated combining together the perfect displacement and perfect mixing scavenging models. It is assumed that when the intake port opens, the fresh mixture is pushing out the burned charge without any mixing and after a multiple of the time needed for the largest eddy to perform one rotation, the two gasses are instantly mixed up together and expelled. The result is a very simple algorithm that does not require much computational time and is able to estimate with high level of precision the trapping efficiency and the residual gas fraction in 2 stroke engines. The tuning and the validation of this algorithm are performed by measuring the trapping efficiency. These measurements are conducted with an innovative technique which consists in measuring the inlet and exhaust temperature, and calculation of the blow down temperature from the pressure trace. The model was tested using a mini high speed 2 stroke HCCI engine fuelled with diethyl ether between 10,800 and 19,000 [rpm].},
  author       = {Manente, Vittorio and Tunestål, Per and Johansson, Bengt},
  booktitle    = {SAE Technical Paper Series},
  issn         = {0148-7191},
  keyword      = {Internal Combustion Engines,Two-Stroke},
  language     = {eng},
  publisher    = {Society of Automotive Engineers},
  title        = {A Novel Model for Computing the Trapping Efficiency and Residual Gas Fraction Validated with an Innovative Technique for Measuring the Trapping Efficiency},
  url          = {http://dx.doi.org/10.4271/2008-32-0003},
  volume       = {2008-32-0003},
  year         = {2008},
}