Team

Internal combustion engines are the most common mean of propulsion for cars today and

forecasts predict that this will not change in the next decades. Therefore research is

necessary for a further increase of efficiency and decrease of emission. A very promising

approach for low- and mid-load operation in Direct Injected Spark Ignited (DISI) engines

is stratified combustion. In this operation mode, a small quantity of fuel is injected

late in the compression, so that a stratified mixture is formed. While this leads to

increased efficiency of up to 20%, it also leads to higher cycle-to-cycle fluctuations

which can cause incomplete combustion or misfire. Understanding the interaction of charge

motion, injection and combustion is therefore essential for future research.

Method and Theory

The steady progress of high speed laser diagnostics like particle image velocimetry (PIV)

allows capturing the flow field inside the engine at a repetition rate of a few CAD. This

enables a detailed study of the development of the charge motion during individual

cycles, as well as the interaction with the spray. Further diagnostic techniques like the

recording of chemiluminescence of the flame or Planar Laser Induces Flourescence (PLIF)

will be added to investigate the combustion process.