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Due to the large negative impact of combustion gas emissions on air quality and the more stringent environmental legislation, research on internal combustion engines (ICE) are being developed to reduce emissions of pollutant gases to the atmosphere. One of the research fronts is the use of lean mixtures with the pre-chamber ignition system (PCIS). This system consists of a pre-chamber (PC) connected to the main chamber by one or more interconnecting holes. A spark plug initiates combustion of the mixture present in the pre-chamber, which is propagated as gas jet into the main chamber, igniting the lean mixture present therein. The gas jets have high thermal and kinetic energy, which promote faster combustion duration, making the system less prone to knock and with lower cyclic variability of the IMEP, enabling the lean limit extension. The pre-chamber system can be assisted with a supplementary liquid or gaseous fuel injection, enabling the charge stratification.

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.

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.

Along the last thirty years one of the challenges is to develop an engine working with ethanol with the same performance and characteristics of gasoline engines functioning at low temperatures. In Brazil the production expansion of flex fuel engines is the main motivation for technology development and research to improve the engine cold start and functioning, when using ethanol. The use of gasoline as an auxiliary in the cold start system is now the main characteristic of this system. In this work the performance of a new cold start system is analyzed. Tests were performed in a vehicle and the results show the potential of the new technology.

For many years durability tests engineers have worked in the sense of improving the tests that, at first, were performed using public roads with high time consumption and low reproducibility. Proving grounds were specially designed to reproduce the most important efforts to the body and chassis systems, but time problem was still there. Time and cost reduction allied to the needs of quality, reliability and reproducibility improvement led the engineers to develop methods and equipments to reproduce the durability tests in the lab. In this way the road simulators appear as a powerful tool able to perform durability tests with high reliability, self-controlled and with very low time compared to the road tests. At this scenery bench tests were also created to components and systems mainly used to anticipate problems before a whole vehicle test.

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.

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.

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.

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.

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.

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.

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 limited thermal efficiency in internal combustion engines provides a partial transformation of fuel energy in net power. The heat lost through the exhaust gases represent a significant portion of energy looses. The Seebeck Effect is the direct conversion of temperature differences between two dissimilar metals or semiconductors into electrical voltage. The present study demonstrates the application of thermoelectric generators technology in Baja SAE vehicles to recovery exhaust heat looses, using thermal energy converter devices. The electrical energy produced in Seebeck Effect Cells, assembly in engine exhaust manifold, is conditioned and applied in vehicle batteries and supply energy consumption during vehicle operation. This action could increase the vehicle energy efficiency by the recovery the thermal energy dissipated. This extra power supply makes possible the reduction of on board batteries charge capacity and also recharges them without external power sources.

This paper discusses the importance of vibration transmitted from the ground to the driver from the perspective of human whole-body vibration (WBV). The scope of analysis is to compare the main vehicle frequencies with those important from the human vibration health and comfort point of view. That was performed by mapping the vibration transmissibility present in different sub sections of the vehicle. The first is the transmissibility between the axles and the chassis rail, the following between the chassis rail and the cabin. The last would be between the cabin and the drivers' seat, although that was not possible from the acquisition point of view. The vehicles measured have mechanical suspension and elastomeric cabin coupling. It is known that all suspension systems in vehicle are highly nonlinear, although here linear dynamic analysis methods were used.

This work aims to study the selection of a heat exchanger available in the market with the objective of implementing it in a vehicle. The vehicle used for the tests was a prototype, developed by Formula UFMG team. It was made an experimental and a theoretical study in order to calculate the power of the CB600F engine to compare with the experimental study of heat dissipation of the selected heat exchanger. This comparison was made to check whether the heat exchanger reaches the vehicle’s requirements, and it has shown good convergence. The engine technical features were used in the theoretical studies, and thus the power was calculated. The experimental data were obtained by assembling the car in a roller dynamometer with the necessary instrumentation for these tests being performed. In these tests, the critical operation conditions of the vehicle were simulated, once the engine operates at a temperature of 95°C.

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.