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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.

Diesel engines have been used on the aeronautical market for a long time. Despite this fact, there are few studies showing the potential cost savings of using this type of technology. In this way, the goal of this paper is to find out whether or not it is advantageous to use an Otto or Diesel cycle engine on general aviation light aircraft. It is well known that both of them have pros and cons, however, the possibility of using Jet A-1 (kerosene) as fuel gives the Diesel engine a clear advantage in a market like Brazil, where the price of the regular piston fuel (AvGas) keeps rising to astonishing values. Throughout this paper, a detailed study of the fixed and variable costs of two similar aircraft, both Cessnas 172 equipped with Otto and Diesel cycle engines is conducted, comparing fuel consumption, performance levels, and other factors.

The technological development of automotive engines is focused on alternative energy sources and optimized use of conventional fuels. The current flexible engines in Brazil can operate with gasohol and ethanol blends in any proportion, but the flexibility is restricted to liquid fuels. The present investigation consists on the use of electronic injection systems for ethanol and for CNG, allowing the use of these fuels simultaneously. The objective of this work is to determine the best proportion of CNG-ethanol mixture in order to maximize the use of the natural gas, fuel which offers the lowest BSFC on conventional SI engines. The low volumetric efficiency inherent in the use of CNG is compensated by the injection of a small quantity of ethanol. The latent heat of vaporization of the alcohol is used to take heat from the intake air and increase its mass, taking advantage from the high latent heat of vaporization of the ethanol and the low BSFC of the CNG.

The torch ignition system consists in the inflammation of the air/fuel mixture by means of gases jet flames that constitute ignition lines. Engines with this feature have a cavity or combustion pre-chamber, physically separate from the main chamber. In these systems happens a larger turbulence generation, due the movement of the gases inside the pre-chamber and through the interconnection orifices. The charge stratification, by means of an auxiliary inlet fuel system, also contributes for the fast and insurance inflammation of lean mixtures and the most varied combustible, including the difficult direct spark ignition fuels. This work presents the design elaboration of combustion pre-chamber from an analysis of the influence of the main constructive parameters in the combustion process.

In this work is proposed the installation of a turbocharger in a low dislocated volume engine, aiming to achieve a higher effective mean pressure and air fuel mixture density, for a better performance of the converted engine. This analysis is made through experimental tests in a break bench, following the Brazilian standard NBR ISO 1585. The results presented shows the basic behavior of the torque curves, power and gas emission, which reflects the changes in performance with both fuels for a aspirated and turbocharged engine, for all the engine rotation speeds. These results show the technical and economical viability of the conversion to Vehicular Natural Gas of a low cc engine, when adapted a commercial turbocharger kit.

This work presents a full analysis of a bi-fuel engine converted to natural gas and aims to survey the main performance losses and the advantages in specific consumption and toxic emissions. With this purpose, dynamometric tests and curves survey of a Fiat Palio 1.6, 16V engine, according to Standard NBR ISO 1585. Tests were made using diverse mixers, trying to obtain the losses caused by this device when the engine is working with gasoline, after the conversion. Tests were performed for different ignition advances, with manual and electronic VNG flow control systems. Trials for many differents low gear engine regulation, looking for consumption reduction and lower emission rates. The gas pressure reducer was tested with and without heating, showing differents results, mainly for emission rates. Other than comparing different components and different engine operation conditions, an analysis of two different natural gas conversion kits were performed, both extensile used in Brazil.

The trends in the development of spark ignition engines leads to the adoption of lean mixtures in the combustion chamber. Torch ignition systems have potential to reduce simultaneously the NOx and CO emissions, while keeping the fuel conversion efficiency at a high level. This study aims to design and analyze a torch ignition system running with ethanol on lean homogeneous charge, adapted to an Otto cycle single-cylinder engine with optical visualization. The main objective is to achieve combustion stability under lean burn operation and to expand the flammability limit for increasing engine efficiency by means of redesigning the ignition system adapting a pre-chamber to the main combustion chamber. Experiments were conducted at constant speed (1000 rpm) using ethanol (E100) as fuel, for a wide range of injection, ignition and mixture formation parameters. Specific fuel consumption and combustion stability were evaluated at each excess air ratio.

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.

Global climate change and an increasing energy demand are driving the scientific community to further advance internal combustion engine technology. Invented by Sr. Henry Ricardo in 1918 the torch ignition system was able to significantly decrease engine’s fuel consumption and emission levels. Since the late 70s, soon after the Compound Vortex Controlled Combustion (CVCC) created by Honda, the torch ignition system R&D almost ceased due to the issues encountered by very complex and costly mechanic control systems that time. This work presents a stratified torch ignition prototype endowed with a sophisticated electronic control systems and components such as electro-injectors from direct injection systems placed on the pre-combustion chamber. The torch ignition prototype was tested and its performance are presented and compared with the baseline engine, which was used as a workhorse for the prototype engine construction.

Reducing environmental pollution by the transport sector has been influenced according to the increasingly restrictions imposed by regulatory standards. For this, legislation such as Euro (at global level) and Proconve (at local level) set new limits each new phase, usually stipulating reductions in the levels of greenhouse gas emissions. Compliance with these requirements is seen with the vehicle or engine ratings working through the conditions imposed by a standard test cycle. However, standard driving conditions often do not represent the real-world driving conditions, being influenced by relief, traffic lights and other peculiarities of each city or route. This paper aims to compare real-world driving cycles of urban bus and passenger car in the city of Santa Maria, in southern Brazil, with the conditions used for light gasoline vehicles and heavy diesel vehicles approval.

Resistive forces are a great source of fuel consumption in vehicles. In particular, rolling resistance represent the major resistance force at low speeds. It is highly influenced by the inflation pressure of the tire and vertical load over it. In the present work, a computer model is created with the objective of investigating the influence of tire inflation pressure on fuel consumption and rolling resistance force. Pressure is varied and parameters analyzed at different vehicle speeds for two different calculation methods. Results show significant decrease in fuel consumption and rolling resistance force as inflation pressure is augmented.

For metallic tanks in contact with aqueous solution, it is always observed the presence of electrochemical corrosion. This process can cause both economic and environmental damage. In the automotive industry, fuel tanks systems have been studied in order to propose new materials to replace the plastic tanks or tanks with metallic coatings. Plastic tanks have the disadvantage of not being recyclable. In the other hand, for metallic coated tanks, tin is used as a coat material and, for this reason, the external tank side must be painted, making its productive process more expensive and generating higher amount of waste. Nowadays, organic-metallic coated tanks, in which, nickel and aluminum are the metals present, can be found. These coatings show potential application; because they do not use heavy metals in their composition and they do not require external painting, allowing a lower production cost.

The focus of this study was to create a methodology to evaluate spray characteristics in a gasoline direct injection injector by means of an automatic process. Computational codes were used to get information about cone angle and breakup length based on images got from injection process. A mathematical function was created to locate the boundaries of the spray and the cone angle was studied as the angle of arcs situated within these boundaries. The centre of the arc was located on the orifice of the injector and a value of angle was associated with several distances from orifice. The breakup length was associated as a distance from the orifice of an arc formed by a group of pixels with the maximum standard deviation related to the values of these pixels. The velocity field was studied by the Particle Image Velocimetry technique. Three fluids were tested at this work: water, ethanol and gasoline.

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 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.

Global trends in the development of spark ignition internal combustion engines lead to the adoption of solutions that reduce CO2 emissions and fuel consumption. Downsizing is a well-established path for this reduction, but it is necessary to use other technologies in order to achieve these ever more rigorous levels. A homogeneous torch ignition system is a viable alternative for reducing CO2 emissions with a combined reduction in specific fuel consumption and increased thermal efficiency. Thus a prototype adapted from an Otto engine with four cylinders is used for analysis. The performance and CO2 emission reference data were initially obtained with the baseline engine operating with a stoichiometric mixture. Then for the same conditions of BMEP, angular velocity and gradual lean of the mixture from the stoichiometry, the results of the adapted system are obtained.

Environmental issues and energy security are critical concerns of the most countries. According researchers, excessive growth of land vehicles is one of the biggest contributors to global air pollution and oil reserves reduction. In this context, the use of lean burn technologies emerges as a promising strategy, allowing lower fuel consumption and pollutants emissions. Present work aims to analyze the behavior of a current commercial engine, gasoline fueled, varying the air-fuel ratio without the use of lean burn ignitions technologies. Analysis was performed through bench dynamometer tests, evaluating cylinder pressure, exhaust gas temperature, fuel conversion efficiency, cycle thermal efficiency, coefficient of variation in indicated mean effective pressure, apparent heat release rate, flame development angle and burn duration.

It developed a design and construction methodology of a stratified charge torch ignition system for an Otto engine aiming fuel consumption and pollutant emission reduction. The torch ignition system is made of a combustion pre-chamber equipped with a direct fuel injector, an air injector and a spark plug. Fuel is directly injected in the pre-chamber aiming the formation of a lightly rich air fuel mixture. The combustion process starts in the pre-chamber and as the pressure rises, combustion jet flames are produced through interconnection nozzles into the main chamber. The high thermal energy of the jet flames reduces the combustion time, increases the combustion efficiency and allows the engine to efficiently burn lean air fuel mixture of several kinds of fuel in the main chamber, even those that are difficult to ignite. After the combustion takes place in the pre-chamber, air is also injected to help the exhaust process of the combustion products of the previous cycle.

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.