SFB 606 — project C4
Process Analysis of Diesel-Engine Combustion
Summary
Non-stationary
combustion in internal combustion engines is one main focus of the
Collaborative Research Centre 606, cf. project cluster "Engine
Combustion". Combustion in IC engines consists of a multitude of
phenomena, like the non-stationary, highly turbulent in-cylinder flow, the
injection of liquid fuel, its evaporation and mixing with air, ignition and
combustion (diffusion flames and premixed modes).
The main issue of
project C4 during the second funding period was the investigation of the formation
and oxidation of soot particles in the combustion chamber of engines with
direct fuel injection. For this purpose the RAYLIX-technique was applied inside
the combustion chamber of a rapid compression machine as well as inside the
combustion chamber of a single cylinder Spark-ignition engine with direct fuel
injection. The main goal of the work during the third funding period is to
extend the investigation of the Diesel-engine combustion to the understanding
of the complete process consisting of
(1) Gas
exchange and in-cylinder gas motion,
(2) Fuel
injection and mixture formation,
(3) Combustion
and soot formation, and
(4) Soot
Oxidation and emission behaviour.
On the one hand
from these investigations, the interaction of the different sub-processes with
respect to the formation and oxidation of soot can be better understood, on the
other hand experimental data are provided for development and validation of
accurate simulation submodels, describing the different sub-process phenomena
as well as for the complete process. The experimental data will be used for the
development and validation of combustion submodels in project B11(N) as well as
for the validation of complete process simulation with LES in project C8(N).
In a first step
the parts for achieving optical access into the single cylinder Diesel-engine
will be fabricated. This engine will be used for all experiments carried out
during the third funding period. Various laser based techniques will be applied
for in-cylinder measurements: PIV (particle image velocimetry) for
visualization of the velocity flow field, Mie-scattering to estimate the fuel
spray distribution and RAYLIX/LII to investigate the soot formation. These
laser diagnostic techniques are accompanied by the 2CM to estimate the
temperature distribution as well as the detection of OH-chemiluminescence to
visualize the flame propagation.
