Characterization of fuel injection and mixing process in a GDI engine using CFD
Typ
Examensarbete för masterexamen
Program
Automotive engineering (MPAUT), MSc
Publicerad
2021
Författare
Dongre, Varun
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
In this thesis, computational fluid dynamics(CFD) simulations were carried on a gasoline
direct injection (GDI) engine to study the thermal behavior, Piston fuel film mass
accumulation, Heat release rate and emissions with different injection timings, piston temperatures
and boundary temperatures. Simulating an internal combustion (IC) engine on
any CFD platform is challenging because of its complex moving geometries, varying conditions,
complex chemistry, and changing fluid structure. Gasoline Direct Injection can
help increase engine efficiency and specific power output and reduce exhaust emissions.
Also, simulation of internal combustion engines offers a significant challenge in the field
of CFD research. Moving boundaries of the solution domain, caused by valves’ motion,
piston leads to deformation of the computation grid, which decreases the quality of the
results. The GDI surface file was imported onto the Converge work-space to change case
setup parameters depending on which fuel was used. Also, changes were made during the
simulations to check the resulting behavior with varying parameters.
Once after the initial description of the case setup process, studies of fuel film accumulation
on the piston were investigated. The simulations showed that a mixture of Primary
Reference Fuels (PRF) provided the best results for piston fuel film accumulation,
spray-distribution, in-cylinder temperature, and pressure at particular injection timing
and piston temperature. Lastly, standard physical models such as the Extended Coherent
Flamelet Model (ECFM) combustion model, Imposed Spark Stretch Ignition model
(ISSIM) ignition model, and K-epsilon turbulence model were used for simulations.