The paper is focused on simulation of high-pressure part of
thermodynamic cycle in a four-stroke spark ignition engine. The
main author's ambition is to create the fast and sufficiently
accurate multi-zone simulating tool working on the basis of simple
quasi-dimensional method reflecting a real 3-D combustion chamber
geometry and using the specific approach to transfer and
transformation of species. The introduced procedure combines a
classical kinetic scheme with the flexible Holub's method for
chemical equilibrium to solve serious numerical issues resulting
from chemical kinetics itself. But for the present, the current
version model uses just fast chemical kinetics with direct
transformation of reactants to chemical equilibrium state. New code
is able to work in predictive or inverse mode as well.
Real 3-D combustion chamber geometry is taken into account by
means of in advance created geometrical characteristics to save a
computational time during the simulation. New tool, developed in
AutoLisp programming language environment, can be used for
evaluation of data tables with particular zone volumes and
combustion chamber total volume, areas of border surfaces between
zones and heat transfer areas between particular zones and parts
creating combustion chamber border.
The predictive model version is suitable for the usage inside
the environment of early-stage engine development systems, linking
the combustion chamber geometry with the rate of heat release
prediction, nitrogen oxides emissions and the future prediction of
knocking resistance. The boundary conditions for a preliminary
design of combustion chamber components and other combustion
chamber features are determined as well. Selected three-zone model
results concerning spark ignition version of AVIA engine are
presented here.
The inverse model version is to be combined with experimental
data to determine or verify the important fuel properties, namely
the turbulent flame velocity. In this case, one two-zone model
output using measured data from ŠKODA engine is presented.