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In the actual context, Researchers are making efforts for becoming mobility more sustainable. Whithin it context, the strategy of direct injection of renewable ethanol fuel in spark ignition engines is an interesting alternative for substitution of fossil fuels. In Brazil, the majory part of ethanol fuel production is provenient of sugar cane that has the potential to absorb great quantity of carbon dioxide through the photosynthesis process. The focus of this study was to create a very low computational cost methodology for evaluating the shape of sprays produced by an inwardly opening pressure-swirl injector. The referred injector is to be used in four stroke spark ignition engines for delivering fuel directly inside the combustion chamber. The spray geometry was then predicted by numerical calculations of single droplets trajectories in a purely lagrangian approach. The working fluid injected considered was EXXSOL D60.

In the present work it was studied the flow around the intake and discharge valves of the HONDA CBR 600RR Engine, used in Formula SAE by the team of CEFET-MG, Formula Cefast. Presenting the methodology and experimental results in the measurement of the reversal discharge coefficient of the intake port and the discharge coefficient of exhaust valve of the engine used in the prototype, serving as a starting point for further studies and development of the prototype drive system. These experimental tests were performed on the flow bench infrastructure of the Pontificia Universidade Católica de Minas Gerais, PUC-MG, using the engine head, same model as used in the Formula Cefast team prototype. Necessary parts and adaptations for tests were developed, such as a mechanism for opening and closing the valves during the experiment.

The work focuses on studying ethanol spray behavior injected directly inside a spark ignited internal combustion engine in the compression stroke. An experimental procedure for measuring spray penetration and spray overall cone angle produced by a multi-hole direct injector was developed by means of computational codes written in Matlab environment for working with images of spray injections and to acquire calculated results in an automatic way. The shadowgraph technique with back continuous illumination associated with a high speed recording image process was used in a single cylinder optical research engine for acquiring images of Brazilian ethanol fuel injected at 120° before the top dead center of compression stroke. The process of spray injections occurred with engine speeds of 1000 rpm, 2000 rpm and 3000 rpm. The results showed that spray penetrations decrease and spray cone angle increase when the engine speed is raised.

In this work, atomization parameters were analyzed by the image visualization of spray from a multi-hole direct injection injector, operating in a backpressure chamber. Such characteristics like cone angle and penetration were analyzed for similar fluids concerning gasoline and ethanol - EXXSOL D40 and EXXSOL D60 respectively under an environment pressure of 5 bar, to simulate incylinder condition, and injection pressure of 70, 90, 100 and 110 bar. To control the injection a Motec-M84 and a driver peak and hold were used. A high speed camera was used for recording images of injection process. The spray images were obtained by a 6504 frames per second recording process, applying shadowgraph technique and MatLab codes were written for image treatment. With the data generated, a comparison between the fluid parameters could be made for direct injection under pressurized environment.

The growing demand for more efficient and less polluting engines has lead the scientific community to further develop the road map engine technologies, including direct fuel injection. Direct injection research demands the investigation of spray formation and its characteristics. The present work performs the characterization of the macroscopic parameters of ethanol sprays (E100) produced with a fuel gauge pressure of 80 bar and gauge back pressures of 0, 5 and 10 bar. The sprays analysis was performed using high speed filming by means of Shadowgraph technique. Computational routines of matrix analysis were applied to measure the spray cone angles, penetration and penetration rate. The spray visualization demanded an experimental apparatus composed of a pressurized cylinder with nitrogen, a fuel tank as pressure vessel, an injection driver equipped with a peak and hold module controlled by a MoteC M84, a Phantom V7.3 high speed camera and LEDs for illumination.

A multi-hole direct injection injector was studied by means of image analysis. Methodologies based on an automatic process of cone angle measurement and edge detection were applied for the spray images generated by a 100 bar injection pressure discharged into a pressurized rigid chamber. A criterion based on pixel values was taken to localize the spray edges as angular coordinates and also with x and y position data. The high pixel values were associated with liquid phase while the low pixel values were associated to its absence. Computational codes written in MATLAB environment were used to analyze the numerical matrices associated to the images. Using the written MATLAB codes, a comparison of the effect of atmospheric back pressure, inside the chamber, on the spray pattern, cone angle and spray penetration were evaluated. The chamber was pressurized with 2.5, 5.0, 7.5 and 10 bar of back pressure. The tested fluid injected was EXXSOL D60 for simulating ethanol fuel behavior.

The Stratified Torch Ignition (STI) engine is capable of operating with lean mixture and low cyclic variability. These characteristic significantly decreases fuel consumption and emission levels. In the STI engine the combustion starts at a pre-combustion chamber where a stoichiometric mixture is ignited by an electrical spark. Pressure increase in the pre-combustion chamber push the combustion jet flames through a calibrated nozzle to be precisely targeted into the main chamber. These combustion jet flames endowed with high thermal and kinetic energy assures a fast and stable combustion of a lean mixture formed at the main chamber. A STI prototype were built and tested. The main combustion parameters were obtained from the in-cylinder pressure measured during the experiments. A combustion analysis is carried out to explain the significant improvement of the STI engine in regard to the baseline engine which was used as workhorse for the prototype engine construction.

The emission of nitric oxide (NOx) is the most difficult to limit among numerous harmful exhaust gas components. The NOX emission of internal combustion engines is mainly NO, but it will be oxidized into NO2 quickly after entering the air. NO is formed inside the combustion chamber in post-flame combustion by the oxidation of nitrogen from the air in conditions that are dependent on the chemical composition of the mixture, temperature and pressure. The correlation between NO emissions and temperature in the combustion chamber is a result of the endothermic nature of these reactions and can be described by extended Zeldovich Mechanism. The stratified torch ignition engine is able to run with lean mixture and low cyclic variability. Due to lean operation, the in-cylinder temperature of the STI engine is significantly lower than the conventional spark ignited one. This fact lead to a substantial reduction in NOx specific emission.

A global effort has been made by the scientific community to promote significant reduction in vehicle engine out-emission. To comply with this goal a stratified torch ignition (STI) engine is built from a commercial existing baseline engine. In this system, combustion starts in a pre-combustion chamber, where the pressure increase pushes the combustion jet flames through calibrated nozzles to be precisely targeted into the main chamber. These combustion jet flames are endowed with high thermal and kinetic energy, being able to generate a stable lean combustion process. The high kinetic and thermal energy of the combustion jet flame results from the load stratification. The engine out-emissions of CO, HC and CO2 of the STI engine are presented, analyzed and compared with the baseline engine. The STI engine showed a significant decrease in the specific emissions of CO and CO2.

This study concerns the sprays produced by a single hole direct injection injector through a systematic image treatment methodology. The images were obtained by high speed recording associated with shadowgraph technique. The recording frequency was 6504 Hz. Grayscale images were obtained after a process of histogram adjusting and image subtraction. The spray volume and penetration was evaluated through a process of edge detection in the hollow cone of the spray injection. A criterion based on pixel values was taken to localize the spray edges as angles and x and y position data. The high pixel values were associated with liquid phase while the low pixel values were associated to its absence. Computational codes written in Matlab environment were used to analyze the numerical matrices associated to the images. The high frequency image recording allowed studying the sprays in all its development. The tests were conducted with injection pressure variation.

This study involves the comparison of atomization characteristics of gasoline and ethanol produced by a single-hole gasoline direct injection (GDI) injector. Experiments were performed for the fuel spray characterization, such as: measuring the injected fuel mass flow rate, the droplet velocity and the droplet diameter of atomized fuel as a function of injection pressure. In the injected fuel mass flow rate measurements, an experimental apparatus was used consisting of a nitrogen cylinder, a source of generating pulses, a fuel tank as a pressure vessel and a precision weighing scale. To measure the fuel droplet velocity and droplet diameter, were used the known optical techniques: Laser Doppler Anemometry and Phase Doppler Anemometry (LDA/PDA), respectively. Thus, the performance of fuels can be compared. The average droplet velocity, droplet diameter and characteristic diameter, Sauter Mean Diameter (SMD), were evaluated and analyzed due to the injection pressure.

Gasoline direct injection (GDI) engines have very attractive potential for improving fuel economy and exhaust emissions, especially disadvantages of increased fuel consumption at part load. In this research, a study has been made on the investigations of stratified lean combustion in a wall-air guided type spark-ignition single cylinder optical research engine. Experiments were conducted at constant load (NIMEP 3 bar) using ethanol as fuel, for a wide range of injection, ignition and mixture formation parameters. Engine efficiency and combustion stability were evaluated at each excess air ratio. Optical visualization illustrated the spray behavior and flame propagation. Specific fuel consumption improvement was achieved with lean burn mixtures. Thus, combustion analysis data based on in-cylinder pressure measurement provide useful data for ethanol GDI engine development.

Atomization parameters from the spray produced by a direct injection injector, operating into an engine with optical access were analyzed in this work. Parameters such as cone angle, penetration and spray geometry for determined crank angles and different rotations, with the respective variability, were evaluated for ethanol injection. Images from spray injection were captured for the specified rotation conditions for the angle and geometry analysis. For the penetration analysis, the image acquisition occurred with crank angle variation, obtaining a mean value with respect to the spray displacement of a point of maximum concentration on a specified direction. Lines were adjusted to the penetration data and the penetration rates (velocities) were evaluated through its slopes. For the cone angle and geometry study, an automatic routine in Matlab environment for image processing was used.

Fulfill emission restrictions is the most challenging task of future engines development. In this context, improvements with regard to the spray and mixture formation in internal combustion engines are necessary. Experimental investigation and numerical simulation have been used to predict and analyze complex in cylinder processes. In this paper, a diesel spray characterization using optical diagnostics was made in order to provide input data and boundary conditions for a diesel spray computational fluid dynamics simulation (CFD), using the Eulerian-Lagrangian model. Combining the advantages of Eulerian and Lagrangian approaches, this model is able to predict continuously the whole spray evolution. The main difficulty of numerical spray simulation is the correct representation of the two characteristic spray zones: dense near the nozzle and dilute downstream.

This work shows procedures for analyzing sprays produced by a direct injection injector. The parameters studied were tip penetration, spray pattern, cone angles and velocity profiles. Two different experimental procedures were applied. The first one to get knowledge of the initial stage of injection consisted in recording images in 4000 Hz. With the data obtained, the penetrations and penetration rates were evaluated. The second experimental procedure consisted of using the Particle Image Velocimetry technique to get images and velocity data for getting knowledge of spray pattern, external and internal cone angle and velocity profiles of the spray fully developed. Gasoline and ethanol were the two fluids tested on the experiments. The results showed larger cone angles for gasoline, linear decreasing behavior for velocities on the linear velocity profiles and a transient stage for the magnitude of the velocities in the initial stage of injection.