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Transient EGR in a High-Speed DI Diesel Engine for a set of different EGR-routings
KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Internal Combustion Engines.
KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Internal Combustion Engines.
2010 (English)In: SAE International Journal of Engines, ISSN 1946-3936, Vol. 3, no 1, 1071-1078 p.Article in journal (Refereed) Published
Abstract [en]

EGR has been proven to reduce NOx emissions from diesel engines significantly and is nowadays widely used in production engines. To reach future emission legislation standards, alternative EGR-routings that deliver higher EGR- rates get into the focus of researchers. As the steady-state emissions are reduced more and more, the emission peaks in transient parts of driving cycles gain importance. Therefore it is interesting to analyze the transient behavior of different EGR-routings. In this work, a 1-D simulation is performed in GT-Power for a 1.9 liter passenger car diesel engine equipped with cooled short-route EGR and a variable geometry turbine. For calibration of the simulation, load transients are measured including the measurement of transient EGR-rates using a fast CO2-analyzer and cylinder pressure to obtain heat-release data. A database with heat-release rates for transient combustion is collected to enable the simulation to run with real combustion data at all points of the transients. The transient EGR-rate as well as the intake pressure are used as criteria to chose the right heat-release rate for a certain cycle. A set of different ways of supplying EGR, namely hybrid EGR, pump-assisted EGR and a reed valve in the EGR- circuit are then implemented in the simulation software and analyzed with respect to transient response and fuel consumption. Another aspect of the analysis is the possibility to control the EGR-rate during the transient. This includes positive load transients with EGR-shutoff as well as negative load transients with need for fast EGR-delivery.

Place, publisher, year, edition, pages
2010. Vol. 3, no 1, 1071-1078 p.
Keyword [en]
EGR, transient EGR
National Category
Mechanical Engineering Vehicle Engineering
URN: urn:nbn:se:kth:diva-71792DOI: 10.4271/2010-01-1271ScopusID: 2-s2.0-78649716726OAI: diva2:487094

QC 20120131

Available from: 2012-01-31 Created: 2012-01-31 Last updated: 2014-04-11Bibliographically approved
In thesis
1. Efficiency and Mixing Analysis of EGR-Systems for Diesel Engines
Open this publication in new window or tab >>Efficiency and Mixing Analysis of EGR-Systems for Diesel Engines
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The reduction of fuel consumption and the reduction of toxic emissions are the main goals of research and development in the area of internal combustion engines. The use of exhaust gas recirculation (EGR) to come further in that direction is today an established method for diesel engines. EGR reduces the emissions of nitrogen oxides with a low penalty in fuel consumption.

The increasingly hard regulations on emissions put high pressure on the manufacturers to improve these systems. The present work aims at increasing the knowledge in the area of EGR. Two of the main challenges when applying EGR are addressed, efficiency and mixing.

The efficiency of the EGR-system is analyzed, focusing on keeping the fuel penalty low for a given EGR-rate. Different layouts of the EGR system are studied and compared regarding their stationary and transient properties. Exergy analysis is used to show the potential for improvement in different system components. In the same time, exergy analysis as a tool is introduced and compared to energy analysis of a system. The usefulness of exergy analysis of the entire gas exchange is shown by the example of a heavy-duty diesel engine.

The problem of EGR and air mixing is approached by a detailed study of the mixing process in a heavy-duty diesel engine. Different methods for the measurement of EGR distribution are presented and compared. Additionally, the possibility to predict the mixing effects by 1-D and 3-D simulation is assessed. It is shown that the mixing between air and EGR is highly dependent on the pulsating nature of the flow. The EGR is shown to be transported in packets in the air flow. This leads to the conclusion that mixing not only at the mixing point, but also mixing in flow direction needs to be optimized, as the distribution of EGR between the cylinders is dependent on the timing between the passage of the EGR packets and the valve opening time.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2014. viii, 75 p.
TRITA-MMK, ISSN 1400-1179 ; 2014:01
EGR, Exergy, mixing, pulsating flow, HP-EGR, LP-EGR, high-pressure EGR, low-pressure EGR
National Category
Other Mechanical Engineering
urn:nbn:se:kth:diva-140850 (URN)978-91-7501-997-0 (ISBN)
Public defence
2014-02-28, Kollegiesalen, Brinellvägen 8, KTH, Stockholm, 14:00 (English)

QC 20140203

Available from: 2014-02-03 Created: 2014-02-02 Last updated: 2014-02-03Bibliographically approved

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Reifarth, SimonÅngström, Hans-Erik
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