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Ethanol and gasoline are widely used with fuels in Otto cycle engines. These fuels have different heating power and octane number and the engine behaves differently depending on the type of fuel used. The objective of this study is to measure, compare and investigate the factors that affect the block vibration of an internal combustion engine as a function of the fuel used ethanol or gasoline. The experiment consisted of instrumenting the side of the engine block with an accelerometer to measure the level of vibration intensity of the engine running on a bench dynamometer varying engine speed and load conditions. The results showed that the engine vibration level increases with the increase in engine speed and load. The highest level of vibration was achieved in the region of maximum torque and maximum pressure combustion. The combustion process is mainly responsible for the highest level of vibration achieved with ethanol.

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.

Fossil fuels and biofuels usage in internal combustion engines are the main source for vehicular propulsion. This justifies the intense worldwide research and development to comply with the challenges of increasing efficiency and emissions reduction. The modeling of commercial fuels and engine combustion processes presents great challenges. There is also the need to better understand how different fuel components interact and influence engine combustion and performance parameters. In previous works, components selection and engine dynamometer tests were done to identify representative surrogate fuels for commercial Brazilian gasoline. It was concluded that formulations with n-heptane, iso-octane, toluene and ethanol can be used to model oxygenated gasolines. Methodologies were implemented to evaluate the influence of the fuel components on fuel properties and several engine combustion and performance parameters.

This study analyzes the design of a two-stage reusable satellite launch vehicle. This launcher was designed to orbit payloads of up to 500 kg to low orbits (LEO). Two RISCRAM™ jet engines (Rocket Ignited Supersonic Combustion Ramjet) power the first stage that is fully reusable. They aspirate atmospheric air and allows speeds of up to Mach 6, below 30 km, and Mach 15 above 40 km of altitude. The second stage is powered by a solid rocket motor that carries the payload at the orbital speed of Mach 24. In this work are presented details of the concept of the vehicle and an economic feasibility analysis of system operation. Launch cost estimative are made and compared to the values of the current satellite launchers that are not reusable. The conclusion of the article is that the proposed system would be able to reduce by an order of magnitude the cost of placing the kilogram of payload in low orbit.

This paper relates to the wind tunnel balance design that aims to meet the need for reliable but more affordable equipment that could accurately perform Aerodynamic measurements and act on three axes, being a Multitasking device, adaptable for prototypes of aircrafts, automobiles, buildings, sports products design, etc., through digital control that will measure the drag, lift and the aerodynamic pitch moment. The main task is stimulating creativity, to solve real problems and reduce technology dependence. The composite tubes used in the fixation of the "Sting-Compound" were chosen to avoid inaccurate measurements and have high flexural strength, even with a small cross section. That's feature is justified because the terminal velocity of wind tunnel is 50 m/s (97 knots), enabling to search many different model sizes and subsonic Reynolds speed regime.

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.

Gasoline is a complex mixture, composed of hundreds of different hydrocarbons. Surrogate fuels decrease the complexity of gasoline and are being used to improve the understanding of internal combustion engines (ICEs) fundamental processes. Computational tools are largely used in ICE development and performance optimization using simple fuels, because it is still not possible to completely model a commercial gasoline. The kinetics and interactions among all the chemical constituents are not yet fully understood, and the computational cost is also prohibitive. There is a need to find suitable surrogate fuels, which can reproduce commercial fuels performance and emissions behavior, in order to develop improved models for fuel combustion in practical devices, such as homogeneous charge compression ignition (HCCI) and spark ignition (SI) engines. Representative surrogate fuels can also be used in fuel development processes.

Exhaust Gas Recirculation - EGR - is a well-known technique to reduce NOx and it’s been applied on Diesel engines for a long time. Later studies and application found that other benefits can be achieved with PFI and GDI gasoline engines, such as pumping loss minimization and efficient knock control. Variable valve actuation valve-trains brought broader application possibilities as it enables full internal EGR control without external paths, high precision and response, as required on transient work modes. Comprehensive investigation on PFI and GDI Spark Ignition engines with external Hot EGR and Cooled EGR are widely available. However, variable valve actuation EGR control review on a flexfuel application is not well explored, and this paper is aimed at doing such.

The pollutants emitted by fuel burn in an internal combustion engine are harmful to humankind health. One of undesirable pollutants are the nitrogen oxides (NOx), witch in the presence of sunlight is responsible by photochemical mist, forming products that irritates eyes, respiratory system and may damage plants. The present article aims to present the theoretical potential reduction in volumetric emissions of nitrogen oxides (NOx) in an internal combustion engine operating with the torch ignition system and homogeneous charge. Therefore, a calculation methodology based in measured pressures and determined temperatures were implemented to check the potential reduction in these pollutant emissions. The presented methodology used to estimate the NOx formation is based in NO formation model presented by [1].

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.

One-dimensional models for internal combustion engines analysis are very useful to simulate its systems through a relatively low computational effort. Based on this idea, this paper presents the simulation of a spark-ignition engine using one-dimensional models implemented in object oriented programming by the authors. The model was adapted to simulate a research four valves, single cylinder, spark ignition, reciprocating internal combustion engine. The gas in the cylinder was described by conservation equations, including the momentum conservation equation, that wasn’t found in the checked literature. For the combustion, a two zones model was implemented, based on combustion wave equations, such that detonation and deflagration are calculated by the same set of equations. The flame propagation geometry was considered to be spherical.

A burning process in a combustion chamber of an internal combustion engine is very important to know the maximum temperature of the gases, the speed of combustion, the ignition delay time of fuel and air mixture exact moment at which ignition will occur. The automobilist industry has invested considerable amounts of resources in numerical modeling and simulations in order to obtain relevant information about the processes in the combustion chamber and then extract the maximum engine performance control the emission of pollutants and formulate new fuels. This study aimed to general construction and instrumentation of a shock tube for measuring shock wave. As specific objective was determined reaction rate and ignition delay time of diesel, biodiesel and ethanol doped with different levels of additive enhancer cetane number. The results are compared with the ignition delay times measured for other authors.

Gasoline is composed of hundreds of components. The fuel properties can present a wide range of variation, depending on the formulation. Commercial fuel specifications differ from country to country, based on the features of each market. Also, fuels for some specific engine applications can differ widely from commercial fuels. For the next decades it is expected that the fossil fuels and bio-fuels usage in internal combustion engines remains to be the main source for vehicular propulsion. This justifies the intense worldwide research and development to comply with the challenges of increasing efficiency and emissions reduction. In this context the fuel can play an important role, mainly when there is the possibility to optimize fuel formulation, engine design and engine calibration for the desired application.

A burning process in a combustion chamber of an internal combustion engine is very important to know the maximum temperature of the gases, the speed of combustion, the ignition delay time of fuel and air mixture exact moment at which ignition will occur. The automobilist industry has invested considerable amounts of resources in numerical modeling and simulations in order to obtain relevant information about the processes in the combustion chamber and then extract the maximum engine performance control the emission of pollutants and formulate new fuels. This study aimed to general construction and instrumentation of a shock tube for measuring shock wave. As specific objective was determined reaction rate and ignition delay time of diesel, biodiesel and ethanol doped with different levels of additive enhancer cetane number. The results are compared with the ignition delay times measured for other authors.

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 problems of vibration and noise from an internal combustion engine are common because of the wide variety of parts and components that make up an internal combustion engine. In recent years engines have evolved considerably in relation to the control of vibration and noise emitted, since these effects reduce the useful life of the internal components of the engine itself and, besides giving discomfort to the occupants of the vehicle. The objective of this work was to identify and describe the main sources of vibration and noise in an internal combustion engine. The methodology used in this work involved instrumentation of an internal combustion engine (Otto cycle), the experimental tests of the engine on a test bench and involved the application of analytical techniques for treatment and analysis of experimental data.

A burning process in a combustion chamber of an internal combustion engine is very important to know the maximum temperature of the gases, the speed of combustion, and the ignition delay time of fuel and air mixture exact moment at which ignition will occur. The automobilist industry has invested considerable amounts of resources in numerical modeling and simulations in order to obtain relevant information about the processes in the combustion chamber and then extract the maximum engine performance control the emission of pollutants and formulate new fuels. This study aimed to general construction and instrumentation of a shock tube for measuring shock wave. As specific objective was determined reaction rate and ignition delay time of ethanol doped with different levels of additive enhancer cetane number. The results are compared with the delays measured for the ignition diesel and biodiesel.

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.

Commercial gasoline is composed of hundreds of hydrocarbon components. Surrogate fuels that decrease the chemical and physical complexity of gasoline are being used to allow a better understanding of the processes involved in the interaction between fuels and internal combustion engines (ICEs). Based on previous published works about methodologies for fuel development using surrogate fuels, the aim of this paper is to present further results on the effect of individual components and fuel fractions on the combustion and performance parameters of spark ignition engines. SI engine dynamometer tests were conducted using ten mixtures of iso-octane, toluene, n-heptane and ethanol. Response surface models were statistically developed to analyze the interactions between fuel components, fuel properties and engine performance.