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Simulation of System Brake Efficiency in a Double Compression-Expansion Engine-Concept (DCEE) Based on Experimental Combustion Data

Lam, Nhut LU ; Tunestål, Per LU and Andersson, Arne (2019) SAE International Powertrains, Fuels & Lubricants Meeting In SAE Tecnical Papers
Abstract
The double compression-expansion engine concepts (DCEE) are split-cycle concepts where the compression, combustion, expansion and gas exchange strokes occur in two or more different cylinders. Previous simulation studies reveal there is a potential to improve brake efficiency with these engine concepts due to improved thermodynamic and mechanical efficiencies. As a continuation of this project this paper studies an alternative layout of the DCEE-concept. The concept studied in this paper has three different cylinders, a compression, a combustion and an expansion cylinder. Overall system indicated and brake efficiency estimations were based on both engine experiments and simulations. The engine experiments were carried out at 10 different... (More)
The double compression-expansion engine concepts (DCEE) are split-cycle concepts where the compression, combustion, expansion and gas exchange strokes occur in two or more different cylinders. Previous simulation studies reveal there is a potential to improve brake efficiency with these engine concepts due to improved thermodynamic and mechanical efficiencies. As a continuation of this project this paper studies an alternative layout of the DCEE-concept. The concept studied in this paper has three different cylinders, a compression, a combustion and an expansion cylinder. Overall system indicated and brake efficiency estimations were based on both engine experiments and simulations. The engine experiments were carried out at 10 different operating points and 5 fuelling rates (between 98.2 and 310.4 mg/cycle injection mass) at an engine speed of 1200 rpm. The inlet manifold pressure was varied between 3 and 5 bar. Due to concerns with structural stability the peak cylinder pressure during the engine experiments was limited to 210 bar. Exhaust backpressure was limited to 8 bar due to thermal stress on the exhaust valves. The engine experiments reveal that a gross indicated efficiency (GIE) of 47 % is achieved at most of the operating points. There were cases where GIE was below 45 % due to high heat loss and degraded combustion efficiency.
The data obtained from the engine experiments were then used as input into the full DCEE-engine simulations. System brake efficiency was determined by estimating friction loss in the simulations. These simulations and friction estimations suggests a system brake efficiency of 41.8 % at the lowest fuelling rate (98.2 mg/cycle) is achieved. Increasing engine load improves efficiency due to lower relative intercooling loss and improved mechanical efficiency. A peak system brake efficiency of 52.8 % is achieved at a very high injection mass (275.6 mg/cycle) and 5 bar Pinlet setting. A further increase in injection mass to 310.4 mg/cycle results in a high increase in heat loss which causes system brake efficiency to decrease to 49.9 %. (Less)
Abstract (Swedish)
The double compression-expansion engine concepts (DCEE) are split-cycle concepts where the compression, combustion, expansion and gas exchange strokes occur in two or more different cylinders. Previous simulation studies reveal there is a potential to improve brake efficiency with these engine concepts due to improved thermodynamic and mechanical efficiencies. As a continuation of this project this paper studies an alternative layout of the DCEE-concept. The concept studied in this paper has three different cylinders, a compression, a combustion and an expansion cylinder. Overall system indicated and brake efficiency estimations were based on both engine experiments and simulations. The engine experiments were carried out at 10 different... (More)
The double compression-expansion engine concepts (DCEE) are split-cycle concepts where the compression, combustion, expansion and gas exchange strokes occur in two or more different cylinders. Previous simulation studies reveal there is a potential to improve brake efficiency with these engine concepts due to improved thermodynamic and mechanical efficiencies. As a continuation of this project this paper studies an alternative layout of the DCEE-concept. The concept studied in this paper has three different cylinders, a compression, a combustion and an expansion cylinder. Overall system indicated and brake efficiency estimations were based on both engine experiments and simulations. The engine experiments were carried out at 10 different operating points and 5 fuelling rates (between 98.2 and 310.4 mg/cycle injection mass) at an engine speed of 1200 rpm. The inlet manifold pressure was varied between 3 and 5 bar. Due to concerns with structural stability the peak cylinder pressure during the engine experiments was limited to 210 bar. Exhaust backpressure was limited to 8 bar due to thermal stress on the exhaust valves. The engine experiments reveal that a gross indicated efficiency (GIE) of 47 % is achieved at most of the operating points. There were cases where GIE was below 45 % due to high heat loss and degraded combustion efficiency.
The data obtained from the engine experiments were then used as input into the full DCEE-engine simulations. System brake efficiency was determined by estimating friction loss in the simulations. These simulations and friction estimations suggests a system brake efficiency of 41.8 % at the lowest fuelling rate (98.2 mg/cycle) is achieved. Increasing engine load improves efficiency due to lower relative intercooling loss and improved mechanical efficiency. A peak system brake efficiency of 52.8 % is achieved at a very high injection mass (275.6 mg/cycle) and 5 bar Pinlet setting. A further increase in injection mass to 310.4 mg/cycle results in a high increase in heat loss which causes system brake efficiency to decrease to 49.9 %. (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
host publication
International Powertrains, Fuels & Lubricants Meeting
series title
SAE Tecnical Papers
article number
2019-01-0073
publisher
Society of Automotive Engineers
conference name
SAE International Powertrains, Fuels & Lubricants Meeting
conference location
San Antonio, United States
conference dates
2019-01-22 - 2019-01-24
external identifiers
  • scopus:85060524222
ISSN
0148-7191
DOI
10.4271/2019-01-0073
project
Motorkoncept 2
language
English
LU publication?
yes
id
cfc05321-b637-4c02-a705-a3464f85beb2
date added to LUP
2019-01-29 14:29:01
date last changed
2020-01-13 01:27:03
@inproceedings{cfc05321-b637-4c02-a705-a3464f85beb2,
  abstract     = {The double compression-expansion engine concepts (DCEE) are split-cycle concepts where the compression, combustion, expansion and gas exchange strokes occur in two or more different cylinders. Previous simulation studies reveal there is a potential to improve brake efficiency with these engine concepts due to improved thermodynamic and mechanical efficiencies. As a continuation of this project this paper studies an alternative layout of the DCEE-concept. The concept studied in this paper has three different cylinders, a compression, a combustion and an expansion cylinder. Overall system indicated and brake efficiency estimations were based on both engine experiments and simulations. The engine experiments were carried out at 10 different operating points and 5 fuelling rates (between 98.2 and 310.4 mg/cycle injection mass) at an engine speed of 1200 rpm. The inlet manifold pressure was varied between 3 and 5 bar. Due to concerns with structural stability the peak cylinder pressure during the engine experiments was limited to 210 bar. Exhaust backpressure was limited to 8 bar due to thermal stress on the exhaust valves. The engine experiments reveal that a gross indicated efficiency (GIE) of 47 % is achieved at most of the operating points. There were cases where GIE was below 45 % due to high heat loss and degraded combustion efficiency.<br/>The data obtained from the engine experiments were then used as input into the full DCEE-engine simulations. System brake efficiency was determined by estimating friction loss in the simulations. These simulations and friction estimations suggests a system brake efficiency of 41.8 % at the lowest fuelling rate (98.2 mg/cycle) is achieved. Increasing engine load improves efficiency due to lower relative intercooling loss and improved mechanical efficiency. A peak system brake efficiency of 52.8 % is achieved at a very high injection mass (275.6 mg/cycle) and 5 bar Pinlet setting. A further increase in injection mass to 310.4 mg/cycle results in a high increase in heat loss which causes system brake efficiency to decrease to 49.9 %.},
  author       = {Lam, Nhut and Tunestål, Per and Andersson, Arne},
  booktitle    = { International Powertrains, Fuels & Lubricants Meeting },
  issn         = {0148-7191},
  language     = {eng},
  month        = {01},
  publisher    = {Society of Automotive Engineers},
  series       = {SAE Tecnical Papers},
  title        = {Simulation of System Brake Efficiency in a Double Compression-Expansion Engine-Concept (DCEE) Based on Experimental Combustion Data},
  url          = {http://dx.doi.org/10.4271/2019-01-0073},
  doi          = {10.4271/2019-01-0073},
  year         = {2019},
}