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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 aim of this work is to present the preliminary performance studies of the unmanned, lightweight (less than 10 kg), supersonic research aircraft. The studies comprise the typical mission for the aircraft's first supersonic version, based on the aerodynamic, thrust, and mass characteristics presented in a previous work. The aircraft, named as “Pohox”, is an Unmanned Air Vehicle, or “UAV”, and is intended to be the flying test bed for a multi cycle engine capable to provide thrust in subsonic, transonic and supersonic regimes. Different tools have been developed to perform the analysis. In the analysis, different flight paths are considered in order to provide insights in terms of fuel consumption, altitude and speed gain. Aircraft ‘excess power’ diagrams have been generated, to provide guidance for the definition of the flight paths to be analyzed. Drag dependency with Mach number is considered in the analysis.

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.

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.

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.

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.

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.

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.

The internal combustion engines require an efficient cooling system, the high temperatures generates at the time of combustion, reaching 2500 K peak burned gas. The materials used in the construction of the cylinder must operate within a maximum value, as well as the fluid film of lubricant oil. A bad dimensioned cooling system can lead to serious consequences such as loss of engine performance and/or efficiency, pre-ignition and increased exhaust emissions and may even lead to the destruction of the engine. In the torch ignition system overheating of the pre-chamber is even more critical and may lead to significant losses. Thus the torch ignition system requires an efficient cooling to prevent deterioration of the pre-chamber and consequently the engine caused by overheating. The solution proposed to resolve this inconvenience is the use of the cooling gallery in the cylinder head, for cooling the pre-chamber that is selected.

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.

An torch ignition system with homogeneous charge is numerically analyzed using a one-dimensional computational model. The new ignition system is implemented in a four-cylinder engine, spark ignition, 1600 cm3, 16 valves. Parameters such as mass burn fraction profile and pressure vs crank angle are compared with experimental data obtained with the torch ignition system operating homogeneous charge with stoichiometric mixture. The computational model uses information such as the pre-chamber pressure as a function of crack angle, intake and exhaust pressure, volumetric efficiency, maps of injection and ignition, valve discharge and valve intake coefficient, lifting valve, laminar flame speed, among others parameters.

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.

Driven by the necessity to reduce costs and improve products quality the automotive industry replaced the design method known as "trial and error" by those grounded on mathematical and physical theory. In this context, a longitudinal performance test was made by BAJA SAE UFMG team, in order to acquire vehicular performance data that will be used to validate computer models. The methodology consists of sensors and data acquisition system research, validation, fixation and installation in the vehicle, test and process of acquired data. From these steps, correlated data were acquired from magnitudes such as angular velocity in transmission shafts, global longitudinal acceleration and velocity, travel of break and throttle pedals and pressure inside of master cylinder. These results developed the knowledge about vehicular dynamic allowing the improvement of futures prototypes.

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.

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.

The automobile industry and its growing commitment to the environment have collaborated in the development of technologies to reduce emissions of gaseous pollutants, including hydrocarbons. Recent works are aimed at the development of the torch ignition in internal combustion engines of the Otto cycle. A prototype characterized by a torch ignition system with fixed geometry of pre-chamber per cylinder, with a volume of 3.66 cm3 and a single nozzle with a diameter of 6.00 mm, fed with homogeneous mixture originating from Combustion chamber. The ignition and injection system was controlled by a reprogrammable electronic management system. The main results were an increase of around 10% in thermal efficiency and reductions of up to 91% in carbon monoxide emissions, but there was a considerable increase in total hydrocarbons (THC) emissions.

One of the biggest challenges for mobility engineers today is the reduction of fuel consumption while keeping or even improving the automobiles propulsion system performance. A great part of the current powertrain components is developed to work at high engine loads and extreme environmental conditions, among which the engine cooling system, for example. As the overall vehicle efficiency depends directly on the thermal system design, it is important to make a careful investigation of the external ambient to develop this system on the best possible way, seeking to minimize the negative impacts at normal driving situations, which represents the most of the vehicle's life cycle. In this regard, the present paper reports a numerical study about the impacts of different cooling system hardware configurations on the fuel consumption of a turbocharged flex-fuel engine.

Atmospheric pollution is the major public health issue in many cities around the world. Internal combustion engines (ICE) and industries are common sources of pollutants that aggravate this situation. Aiming to overcome this problem, increasingly restrictive legislation on combustion pollutant emissions has been formulated and new technologies are being developed to ensure compliance with such restrictions. In this scenario, the lean mixtures appear as a possible alternative, but also bring some inconveniences such as combustion instabilities. Pre-chamber ignition systems (PCIS) enable a more stable combustion process due to high kinetic, thermal and chemical energy of the gases from the pre-chamber (PC), which pass through nozzles and begin the combustion process of the air-fuel mixture contained in the main combustion chamber (MC). However, some challenges still have to be overcome in the development of these systems, one of the main ones being hydrocarbon (HC) emissions.

Vibration problems in internal combustion engines produce premature wear on the internal components of the engine, which contributes both to reduce the lifespan of the engine itself as well as cause discomfort to the occupants of the vehicle. Thus, since it is impossible to totally eliminate vibrations from engines, it is important to understand the sources of vibration production and control them to acceptable levels. The general objective of this paper is to measure the vibration in the areas that undergo greater efforts due to the processes of combustion and mechanical forces. These areas are the fixed bearings located to the extremes of the crankshaft. The specified objective of this study is to correlate these levels of crankshaft engine vibration relative to the fuel used, ethanol and gasoline, and assess the influence of lubricant oils on the vibration levels as a function of the viscosity of the lubricant.

To attend the new tendencies of the automotive market, new technologies must be used throughout the engine conception. One way of improving the project is to use computational numerical simulation, predicting engine behavior in a wide range of situations. This paper presents a methodology to estimate the engine characteristic parameters necessary to numerical simulation. Morse test was used to determine friction power, mean effective pressure friction and friction torque, considering the engine behavior during cylinder ignition cut-off. In this test all the results were compatible with manufacturer data, which validates the methodology. To define the moment of inertia, it's also proposed a fuel cut methodology, associated with the Morse test, because the torque values measured by dynamometer after the fuel cut did not correspond to the real value. Thus, plausible values of engine moment of inertia, very close to values obtained by software, were obtained.