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The potential of increased efficiency and power for a turbocharged PFI-SI engine through variable valve actuation and DEP

Nilsson, Michael LU and Larsson, Jim (2015) MVK920 20151
Department of Energy Sciences
Abstract
New legislation involving emissions from internal combustion engines are pushing the manu-facturers to develop new technology faster than ever before with the amount of greenhouse gases. To meet the standards new concepts need to be developed with lower fuel consumption and emissions. This thesis covers the implementation of a couple of methods to achieve this. These concepts are DEP with fully variable valves in a port fuel SI engine with high compres-sion ratio (CR). The results show an increase in efficiency followed by lowered fuel consump-tion. The improvements in fuel consumption are mainly found to be the result of raising the CR and because of decreases in pumping losses due to de-throttling via the Miller-cycle. The reduction in... (More)
New legislation involving emissions from internal combustion engines are pushing the manu-facturers to develop new technology faster than ever before with the amount of greenhouse gases. To meet the standards new concepts need to be developed with lower fuel consumption and emissions. This thesis covers the implementation of a couple of methods to achieve this. These concepts are DEP with fully variable valves in a port fuel SI engine with high compres-sion ratio (CR). The results show an increase in efficiency followed by lowered fuel consump-tion. The improvements in fuel consumption are mainly found to be the result of raising the CR and because of decreases in pumping losses due to de-throttling via the Miller-cycle. The reduction in pumping losses by implementing the DEP concept was not as great as expected. The results show a decrease of fuel consumption of 9.5% at part load and 5 % at high load. The main improvement with the DEP concept was the reduction of the in-cylinder residual gases at 40 CAD before top dead centre firing (TDCF). This could be enough to be able to use such high CR that otherwise just wouldn´t be possible.
The thesis reveals many of the difficulties involving combustion simulation and with no ex-perimental work available in particular. The thesis would gain a lot from implementing a pre-dicted combustion model to simulate EGR and the full capability of the DEP concept in terms of affecting the combustion, by for example changing the burn rate. (Less)
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author
Nilsson, Michael LU and Larsson, Jim
supervisor
organization
course
MVK920 20151
year
type
H2 - Master's Degree (Two Years)
subject
report number
ISRN LUTMDN/TMHP-15/5342-SE
ISSN
0282-1990
language
English
id
8170925
date added to LUP
2015-11-16 15:55:01
date last changed
2015-11-16 15:55:01
@misc{8170925,
  abstract     = {New legislation involving emissions from internal combustion engines are pushing the manu-facturers to develop new technology faster than ever before with the amount of greenhouse gases. To meet the standards new concepts need to be developed with lower fuel consumption and emissions. This thesis covers the implementation of a couple of methods to achieve this. These concepts are DEP with fully variable valves in a port fuel SI engine with high compres-sion ratio (CR). The results show an increase in efficiency followed by lowered fuel consump-tion. The improvements in fuel consumption are mainly found to be the result of raising the CR and because of decreases in pumping losses due to de-throttling via the Miller-cycle. The reduction in pumping losses by implementing the DEP concept was not as great as expected. The results show a decrease of fuel consumption of 9.5% at part load and 5 % at high load. The main improvement with the DEP concept was the reduction of the in-cylinder residual gases at 40 CAD before top dead centre firing (TDCF). This could be enough to be able to use such high CR that otherwise just wouldn´t be possible.
The thesis reveals many of the difficulties involving combustion simulation and with no ex-perimental work available in particular. The thesis would gain a lot from implementing a pre-dicted combustion model to simulate EGR and the full capability of the DEP concept in terms of affecting the combustion, by for example changing the burn rate.},
  author       = {Nilsson, Michael and Larsson, Jim},
  issn         = {0282-1990},
  language     = {eng},
  note         = {Student Paper},
  title        = {The potential of increased efficiency and power for a turbocharged PFI-SI engine through variable valve actuation and DEP},
  year         = {2015},
}