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The fuel injection in internal combustion engines plays a crucial role in the mixture formation, combustion process and pollutants' emission. Its correct modeling is fundamental to the prediction of an engine performance through a computational fluid dynamics simulation. In the first part of this work a tridimensional numerical simulation of a multi-hole’s injector, using ethanol as fuel, is presented. The numerical simulation results were compared to experimental data from a fuel spray injection bench test in a quiescent vessel. The break up model applied to the simulation was the combined Kelvin-Helmholtz Rayleigh-Taylor, and a sensitivity analysis of the liquid fuel penetration curve, as well on the overall spray shape was performed according to the model constants. Experimental spray images were used to aid the model tuning. The final configuration of the KH-RT model constants that showed best agreement with the measured spray was C3 equal to 0.5, B1, 7 and Cb, 0.

In this work, the in-cylinder flow of a spark ignited Single Cylinder Research Engine (SCRE) with variable compression ratio was simulated using STAR-CD, a Computational Fluid Dynamics (CFD) software with es-ice module for internal combustion engines. The engine used in this work was an AVL SCRE with 82 mm bore and 86 mm stroke. The simulations were made in two different configurations, one with a piston suited for wall guided direct injection and a steel liner (Configuration 1) and another with flat piston and a transparent liner (Configuration 2). Configuration 1 was simulated with the compression ratios of 9.3:1, 11.5:1 and 12.0:1 and had its in-cylinder values of tumble, Turbulent Kinetic Energy (TKE), pressure and temperature analyzed and compared between compression ratios. Configuration 2 was used for validation of in-cylinder flow field using Particle Image Velocimetry (PIV) measurements and experimental in-cylinder pressure. Both configurations were simulated for 1000 RPM.

The use of torch ignition systems in spark-ignition engines represents an interesting option in the efforts to reduce pollutants emission and specific fuel consumption. Based on this idea, this paper presents a 3D model of a prechamber created for a spark-ignition engine and focuses on the numerical analysis of the fluid flow inside the modified chamber. This kind of analysis is very important once it allowed evaluating aspects like turbulence parameters, pressure inside the chamber and prechamber, fluid recirculation and a possible prechamber’s geometry for the engine. The studies were done in a four valve Single Cylinder Research Engine - SCRE. For the numerical modeling and fluid flow investigation it was used STAR-CD Software. The numerical results permitted to characterize the fluid flow in the modified engine and compare it with the standard engine, which showed significant differences and an interesting potential.

The simulation of the fluid dynamics in internal combustion engines has become more important in the past few years for research, development and design of that equipment. The Computational Fluid Dynamics (CFD) methodology is able to analyze the fluid flow in regions the experimental technology cannot afford to. Using a single cylinder research engine, the calculation can be validated from in-cylinder pressure and temperature measurements, also with velocity fields and the related variables. This paper presents the evaluation of the numerical results for tumble and swirl coefficient on internal combustion engines along with its validation. The commercial code STAR-CD, with the ES-ICE module, specific for internal combustion engine, was used for the CFD calculation. Grid independence studies in space and time has been made for reliability of the results.