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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.

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.

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.

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.