Influence of Operating Parameters on the Thermal Behavior and Energy Balance of an Automotive Diesel Engine

  • Christian Donn
  • Daniel Ghebru
  • Wolfgang Zulehner
  • Uwe Wagner
  • Ulrich Spicher
  • Matthias Honzen
Conference paper
Part of the Lecture Notes in Electrical Engineering book series (LNEE, volume 190)


The paper gives a comprehensive overview regarding all relevant operation parameters mainly influencing the energy balance of a state-of-the-art automotive Diesel engine. A detailed experimental analysis of the influence of injection timing and pressure, EGR rate, boost pressure, charge air temperature, coolant temperature and swirl flap position is presented. The investigation includes combustion chamber energy balances based on pressure trace analyses (internal energy balance) as well as outer energy balances that take into account all outgoing and incoming energy flows of the engine based on extensive temperature and flow measurements of the relevant fluids. Measurements of the engine structure temperatures are used to complete the analysis of the thermal engine behaviour depending on the operating parameters. The aim of the paper is to give an overview which operating parameters are crucial for thermal engine application and simulation.


Diesel engine Thermal management Heat flow analysis Energy balance 



Intake air


After top dead centre




Before top dead centre


Crank angle


Charge air cooler


Combustion chamber


Carbon monoxide


Exhaust gas recirculation




Net indicated mean effective pressure

MFB50 %

Mass fraction burned 50 %


Main injection


Pilot injection


Revolutions per minute


Start of injection


Top dead centre


Variable turbine geometry

\( \alpha_{Gas} \)

Gas side heat transfer coefficient (W/(m2K))

\( \dot{H}_{Exh} \)

Exhaust gas enthalpy flow (kW)

\( m \)

Injected mass per cycle (mg)

\( n \)

Engine speed (rpm)

\( \dot{Q} \)

Heat flow (kW)

\( \dot{Q}_{in} \)

Input energy flow (kW)

\( P \)

Power (kW)

\( p_{cyl} \)

Cylinder pressure (bar)

\( T_{gas} \)

Gas temperature (°C)


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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Christian Donn
    • 1
  • Daniel Ghebru
    • 1
  • Wolfgang Zulehner
    • 1
  • Uwe Wagner
    • 1
  • Ulrich Spicher
    • 1
  • Matthias Honzen
    • 2
  1. 1.Karlsruhe Institute of TechnologyInstitut fuer KolbenmaschinenKarlsruheGermany
  2. 2.Audi AGNeckarsulmGermany

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