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Combined Low and High Pressure EGR for Higher Brake Efficiency with Partially Premixed Combustion

Svensson, Erik LU ; Yin, Lianhao LU ; Tunestal, Per LU and Tuner, Martin LU (2017) In SAE Technical Papers
Abstract

The concept of Partially Premixed Combustion (PPC) in internal combustion engines has shown to yield high gross indicated efficiencies, but at the expense of gas exchange efficiencies. Most of the experimental research on partially premixed combustion has been conducted on compression ignition engines designed to operate on diesel fuel and relatively high exhaust temperatures. The partially premixed combustion concept on the other hand relies on dilution with high exhaust gas recirculation (EGR) rates to slow down the combustion which results in low exhaust temperatures, but also high mass flows over cylinder, valves, ports and manifolds. A careful design of the gas exchange system, EGR arrangement and heat exchangers is therefore of... (More)

The concept of Partially Premixed Combustion (PPC) in internal combustion engines has shown to yield high gross indicated efficiencies, but at the expense of gas exchange efficiencies. Most of the experimental research on partially premixed combustion has been conducted on compression ignition engines designed to operate on diesel fuel and relatively high exhaust temperatures. The partially premixed combustion concept on the other hand relies on dilution with high exhaust gas recirculation (EGR) rates to slow down the combustion which results in low exhaust temperatures, but also high mass flows over cylinder, valves, ports and manifolds. A careful design of the gas exchange system, EGR arrangement and heat exchangers is therefore of utter importance. Experiments were performed on a heavy-duty, compression ignition engine using a fuel consisting of 80 volume % 95 RON service station gasoline and 20 volume % n-heptane. A wide range of engine speeds and loads were run using a low pressure EGR system. The experiments served as a validation basis for a one-dimensional simulation model. Using the model, a comparison between low pressure EGR, high pressure EGR and combined low and high pressure EGR was performed. The results showed that the combined low and high pressure EGR configuration could reach an average brake efficiency of 41.6 % while the low pressure EGR and high pressure EGR reached 39.5 % and 39.9 % respectively. The combined configuration reached a higher efficiency because it decreased the mass flow range in which the turbine and compressor needed to work which resulted in a higher overall turbocharger efficiency. The effect of varying the EGR and charge air cooler gas outlet temperatures was also studied. It was concluded that a higher cooler temperature decreased both the brake efficiency and the maximum achievable load due to a higher in-cylinder heat transfer loss.

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Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
SAE Technical Papers
publisher
Society of Automotive Engineers
external identifiers
  • scopus:85034446077
ISSN
0148-7191
DOI
10.4271/2017-01-2267
language
English
LU publication?
yes
id
14b136c1-4af7-4f95-a76b-640ab7661338
date added to LUP
2017-12-11 07:44:26
date last changed
2018-01-07 12:28:04
@article{14b136c1-4af7-4f95-a76b-640ab7661338,
  abstract     = {<p>The concept of Partially Premixed Combustion (PPC) in internal combustion engines has shown to yield high gross indicated efficiencies, but at the expense of gas exchange efficiencies. Most of the experimental research on partially premixed combustion has been conducted on compression ignition engines designed to operate on diesel fuel and relatively high exhaust temperatures. The partially premixed combustion concept on the other hand relies on dilution with high exhaust gas recirculation (EGR) rates to slow down the combustion which results in low exhaust temperatures, but also high mass flows over cylinder, valves, ports and manifolds. A careful design of the gas exchange system, EGR arrangement and heat exchangers is therefore of utter importance. Experiments were performed on a heavy-duty, compression ignition engine using a fuel consisting of 80 volume % 95 RON service station gasoline and 20 volume % n-heptane. A wide range of engine speeds and loads were run using a low pressure EGR system. The experiments served as a validation basis for a one-dimensional simulation model. Using the model, a comparison between low pressure EGR, high pressure EGR and combined low and high pressure EGR was performed. The results showed that the combined low and high pressure EGR configuration could reach an average brake efficiency of 41.6 % while the low pressure EGR and high pressure EGR reached 39.5 % and 39.9 % respectively. The combined configuration reached a higher efficiency because it decreased the mass flow range in which the turbine and compressor needed to work which resulted in a higher overall turbocharger efficiency. The effect of varying the EGR and charge air cooler gas outlet temperatures was also studied. It was concluded that a higher cooler temperature decreased both the brake efficiency and the maximum achievable load due to a higher in-cylinder heat transfer loss.</p>},
  articleno    = {2017-01-2267},
  author       = {Svensson, Erik and Yin, Lianhao and Tunestal, Per and Tuner, Martin},
  issn         = {0148-7191},
  language     = {eng},
  publisher    = {Society of Automotive Engineers},
  series       = {SAE Technical Papers},
  title        = {Combined Low and High Pressure EGR for Higher Brake Efficiency with Partially Premixed Combustion},
  url          = {http://dx.doi.org/10.4271/2017-01-2267},
  year         = {2017},
}