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A CFD three-dimensional analysis of an internal combustion engine was carried out to evaluate the gasoline-ethanol E27 fuel spray and flow characteristics using variable valve timing (VVT) technology. In this study, the fuel injection has been made using port fuel injection (PFI) and the simulations modeled two conditions of valve timing: baseline and retarding the intake valve opening (IVO) 40°. The dynamic performance of this numerical model was validated comparing simulation results of cylinder pressure, mass burned fraction, cylinder temperature, and heat release with experimental data. The effects of in-cylinder fluid flow patterns, such as tumble and swirl, on combustion were numerically investigated for the two studied conditions and it was verified an extreme reduction of swirl when IVO is retarded, besides differences in tumble and cross-tumble.

In this paper, particle image velocimetry (PIV) and computational fluid dynamics (CFD) were employed to a qualitatively and quantitatively study in the behavior of the intake-generated steady flow in a four valve spark ignition single cylinder research engine. Steady flow experimental characterization was made for different intake valve lift values. PIV was used to investigate the flow pattern generated within the engine cylinder. The measurements were taken in the symmetry vertical plane between the inlet and outlet valves. These same conditions were modeled using Star-CCM+ commercial package. The CFD model was used as a less expensive alternative to make a deeper study of the flow field. Velocity fields and intake valves discharge coefficient were compared and analyzed, resulting in a good correlation in relation to the optical experiment.

The design and development of highly efficient internal combustion engines require a thorough investigation of the fluid dynamic processes. This paper presents the experimentally determination and computational fluid dynamics simulations of the intake valves discharge coefficients of a four valve spark-ignition single cylinder research engine. The mass flow rate and air pressure were measured directly in the intake port for six different values of valve lift (4.68; 6.16; 7.48; 8.62; 9.46; and 10.49mm). The theoretical mass flow rates were obtained based on considerations of subsonic flow. Simulations were carried using the Star CCM+ commercial code. Mesh independence studies, using the velocity fields as monitors, have been made for reliability of the simulations. As a result, a methodology was successfully implemented to obtain the discharge coefficients experimentally and the simulations were validated with a maximum deviation of 6.62%.