In the first part of studies, Controlled Auto-Ignition (CAI) combustion was investigated in a Ricardo E6 single cylinder, four stroke gasoline engine. CAI combustion is achieved by employing positive valve overlap configuration in combination with various compression ratios and intake air temperature strategies. The CAI operational region is limited by engine load due to knock and partial burned boundaries. The combustion characteristics and emissions are studied in order to understand the major advantages and drawbacks of CAI combustion with positive valve overlap. The enlargement of the CAI operational region is obtained by boosting intake air and external EGR. The lean-boosted operation elevators the range of CAI combustion to the higher load region, and the use of external EGR allows the engine to operation with CAI combustion in the mid range of region between boosted and N/A CAI operational range. The results are analyzed and combustion characteristics, performance and emissions are investigated. A Ricardo Hydra single cylinder, four stroke optical gasoline engine with optical access is then experimented to investigate CAI combustion through negative valve overlap configuration and an intake heater. The effects of direct fuel injection timings spark timings and air/fuel ratio are studied by means of simultaneous incylinder heat release study and direct visualization, chemiluminescence techniques which uses full, OH radical and CHO species. Both heat release analysis and chemiluminescence results have identified the pressure of minor combustion during the NVO period. Both the charge cooling and local air/fuel ratio effects are also investigated by varying the quantity of direct air injection.

O presente trabalho tem como escopo validar qualitativa e quantitativamente o ensaio de swirl em cabeçotes de motores Diesel realizado de maneira contínua, comparando-o com o padrão estático amplamente aplicado na indústria no controle de qualidade deste componente. A modificação metodológica do ensaio permite ensaios muito mais velozes do que os atuais, podendo, com todas as verificações necessárias, ser extensível a uma linha de montagem, permitindo controle de qualidade diretamente após o processo de usinagem do fundido ou antes de montar o cabeçote no bloco do motor. O presente trabalho apresenta a metodologia aplicada para o tratamento do problema bem como os resultados obtidos até o momento, indicando também os que ainda serão obtidos. No escopo do projeto, apresenta-se de maneira sucinta todo o procedimento utilizado para as simulações estáticas e transiente dos métodos de medição a partir do método do volume finitos de um código comercial, destacando a metodologia para determinação das malhas, seleção dos modelos e esquemas de discretização utilizados, destacando por fim uma comparação entre diferentes aberturas de válvula do ensaio estático e os primeiros resultados da simulação com abertura de válvula ao longo do tempo de simulação. Do ponto de vista experimental, descreveu-se o equipamento utilizado bem como as adaptações realizadas, principalmente no que tangem a automação do controle de válvula, no escopo do presente projeto, apresentando por fim alguns resultados do ensaio contínuo na bancada em comparação com o estático. Os ensaios e simulações numéricas estática e transientes apresentaram coerência em seus resultados. As simulações, quando comparadas entre si e com os resultados do PIV, mostram que os perfis de escoamento são bastante parecidos em todas as situações, o que permite concluir que existe a possibilidade de se realizar o ensaio de swirl de forma dinâmica para esta configuração específica. / The present work aims to validate qualitatively and quantitatively the swirl test in diesel engine heads performed continuously, comparing it with the static standard widely applied in industry in the quality control of this component. The methodological modification of the test allows for tests much faster than the current ones and can be extensible to an assembly line, allowing quality control directly after the cast machining process or before mounting the engine block. The present work presents the applied methodology for the treatment of the problem as well as the results obtained so far, also indicating the ones that will be obtained. In the scope of the project, the whole procedure used for the static and transient simulations of the measurement methods based on the finite volume method of a commercial code is presented, highlighting the methodology for determining the meshes, selection of models and schemes of discretization. At last, a comparison between different valve openings of the static test and the first results of the simulation with valve opening during the simulation time will be presented. From the experimental point of view, the equipment used was described, as well as the adaptations made, mainly in what concerns the automation of valve control, within the scope of the present project. Some results of the continuous test in the bench are presented and compared with the static ones. The static and dynamic tests and simulations presented good coherence among their results. The simulations, when compared one with each other and to the PIV test results, showed great similarities among the in-cylinder flow velocity profiles, what might lead to the conclusion that it is possible to test cylinder heads dynamically, at least with the presented configuration.

Desde a sua invenção, o motor a combustão interna sofreu significantes evoluções, como redução do consumo de combustível, aumento da sua potência e durabilidade a um menor custo. Outros setores também evoluíram, como a busca por alternativas de combustível, tendo como exemplo o etanol hidratado combustível, que trouxe vantagens tais como maior desempenho e menor emissão de poluentes, porém com solicitações mecânicas, térmicas e termomecânicas mais severas. Sua menor lubricidade, quando comparada a da gasolina tipo C também intensificou o desgaste no par tribológico válvula e sede de válvula. Neste trabalho foram analisados diversos pares de válvulas e sedes de válvulas provenientes de quatro motores pós teste, sendo dois deles de mesma especificação técnica e submetidos às mesmas condições de ensaio, variando somente o combustível utilizado (etanol hidratado combustível e gasolina comum tipo C). A topografia da superfície de contato foi avaliada através de exames das superfícies com lupa estereoscópica, microscópio eletrônico de varredura e perfilômetro óptico a fim de identificar os danos encontrados. Ao término das análises foi realizada a comparação dos danos encontrados entre a superfície de contato das válvulas e sedes do motor que operou com etanol hidratado combustível e gasolina comum tipo C, de forma a evidenciar as diferenças proporcionadas pelos combustíveis. Este trabalho faz parte do \"Consórcio de P&D e Desafios Tribológicos em Motores Flex-Fuel\" patrocinado pela FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) com participação da indústria automotiva, para identificar os modos de desgaste atuantes. / Since its invention the internal combustion engine presented significant improvements like lower fuel consumption, higher power and durability increase at reduced costs. Other industries sectors did also improve as the search for new alternative fuels such as hydrated ethanol fuel which brought advantages like higher performance with lower pollutant emissions, although with it came more severe mechanical, thermal and thermo-mechanic stresses. Ethanol lower lubricity when compared to type C gasolines did also increase the valve/ valve seat insert wear. This study presents the results of contact surface analysis of several pairs valve/ valve seat insert from four engines after test being two of them of same technical specification and submitted to the same test cycle with only difference their fuel (hydrated ethanol and regular type C gasoline). The contact surface topography was evaluated through surface exams using optical microscopy, scanning electron microscope and non-contact profiler, to evaluate damages. At the end of analysis, a comparison between valves and valve seats from the engines that operated with hydrated ethanol and regular type C gasoline in order to put in evidence the damage difference provided by the fuels. This study is part of \"Consórcio de P&D e Desafios Tribológicos em Motores Flex-Fuel\", sponsored by FAPESP (\"Fundação de Amparo à Pesquisa do Estado de São Paulo\") with participation of automotive industries, to characterize the existent wear.

A utilização de combustíveis alternativos em MCI, visa a substituição ou a redução do consumo de combustíveis fósseis. Qualquer estudo do desenvolvimento de métodos e técnicas que melhore o desempenho dos motores usando combustíveis alternativos é de grande importância tecnológica, econômica e social. Com este fim, foi feito este trabalho de pesquisa, o qual consiste em ensaiar um motor usando misturas de 37% e 50% de etanol na gasolina. O etanol utilizado neste trabalho apresentou um grau alcoólico de 92 INPM aproximadamente. Os ensaios foram feitos em taxas de compressão 8:1, 9.5:1 e 11:1. Foi avaliada a influência dos diferentes parâmetros para um máximo de eficiência e um mínimo de poluição, aproveitando as vantagens de ambos combustíveis, já que, a gasolina tem alto poder calorífico e baixo índice octano, e o etanol tem baixo poder calorífico e elevado índice de octana. O combustível ideal deveria ter ambos os fatores elevados. Para verificar os resultados esperados, foram feitos neste trabalho, estudos cinéticos químicos da combustão a partir do desempenho do motor e geração de gases. Para cumprir este fim foram necessários estudos que incluem o diagnóstico do processo de combustão, já que, o diagnóstico do processo de combustão fornece toda a informação necessária, às análises de aspectos críticos do funcionamento do motor e de emissões. Comprovou-se que a velocidade da reação de oxidação do etanol é maior que da gasolina e que, o motor aproveita mais a energia química do etanol que da gasolina. / The use of alternative fuels in Internal Combustion engine, seeks the substitution or the reduction of the consumption of fossil fuels. Any study of the development of methods and techniques that it improves the acting of the motors using alternative fuels are of great technological, economic and social importance. With this goal, it was made this research work, which consists of tests in an engine using blends of 37% and 50% of ethanol in the gasoline. The ethanol used in this work presented an alcoholic degree of 92 INPM approximately. The tests were made in compression ratio 8:1, 9.5:1 and 11:1. The influence of the different parameters was evaluated for a maximum of efficiency and a minimum of pollution, taking advantage of the advantages of both fuels, since, the gasoline has high PCI and low octane index, and the ethanol low PCI and high octane index. The ideal fuel should have high both factors. To verify the expected results, they were done in this work, studies kinetic chemists of the combustion starting from engine performance and generation of gases. To execute this goal they were necessary studies that include the diagnostics of the combustion process, since, the diagnostics of the combustion process supplies all the necessary information, to the analyses of engine critical aspects operation and emissions. Was proven that the speed of the ethanol reaction of oxidation is larger than gasoline and that the engine takes advantage of more the ethanol chemical energy that of the gasoline.

As legislações com restrições nos níveis de emissões de poluentes e a grande concorrência entre as montadoras fomentaram o desenvolvimento de sistemas mais eficientes de gerenciamento de motores a combustão interna. Entretanto, a falta de sensores que identifiquem as propriedades da combustão, e que sejam economicamente viáveis, dificulta o desenvolvimento de novos sistemas. Visando suprir parte dessas limitações, este trabalho propõe o uso do sensor de corrente iônica com duas finalidades: identificação dos fenômenos de combustão e detonação. Para identificação da combustão, atualmente é utilizado o sensor de fase instalado no motor, o que encarece o sistema de gerenciamento. Uma alternativa a este sensor seria utilizar a vela de ignição, já instalada dentro do cilindro do motor, como sensor de ionização da mistura ar/combustível durante a queima. Comparando a área sob a curva do sinal da corrente iônica durante a combustão com a área sob a curva durante a admissão, foi possível verificar que é viável a utilização do sinal da corrente iônica para substituição de uma funcionalidade do sensor de fase. Quanto à identificação do fenômeno da detonação, foi mostrado que o uso do sensor de corrente iônica possibilita a remoção do sensor de detonação. Para isso, foi realizada a correlação entre a energia de uma faixa de frequências dos harmônicos do sinal da corrente iônica com a energia do sinal proveniente do sensor de detonação. Dessa forma, este trabalho mostrou que é possível usar somente as velas de ignição, já presentes no veículo, como sensores. Além disso, os resultados positivos obtidos propiciam oportunidades para novas aplicações e novas pesquisas. / The laws that restrict pollutant emission levels and the competition among manufacturers fostered the development of more efficient internal combustion engine management systems. However, the lack of sensors to identify the properties of combustion, and which are economically viable, hinders the development of new systems. In order to address such limitations, this investigation proposes using the ionic current sensor with two purposes: identification of combustion and knock phenomena. The combustion identification is currently identified by the camshaft position sensor installed in the motor, which becomes more expensive for the management system. An alternative is using the spark plug, already installed inside the engine cylinder, such as ionization sensor of air/fuel mixture during combustion. Comparing the area under the curve of the ion current signal during combustion to the area under the curve during admission, it was found that it is feasible the use of ionic current signal to replace one feature of the camshaft position sensor. Concerning the identification of the knock phenomenon, it was shown that the use of the ionic current sensor allows the removal of the knock sensor. For this, the correlation between the energy signal in a frequency range of the ionic current harmonic with the energy of the signal from the knock sensor was performed Therefore, the use of spark plugs as sensors is very promising, in replacement to two existing sensors. Moreover, the positive results provide opportunities for new applications and researches.

Governments across the world are implementing legislation for ever more strict limits for vehicle emissions; combined with customer expectations for growing levels of performance and equipment, automotive manufacturers face a significant challenge. With the aim of meeting this challenge, downsizing is an established trend in passenger car engine development. However, since downsizing is commonly achieved through pressure charging (turbocharging, for example), the associated benefits in improved fuel economy and emissions are often obtained at the expense of engine dynamic response, and, consequently, vehicle driveability. This thesis presents predominantly simulation-based research into a novel combined charging system comprising a conventional turbocharger used in conjunction with a declutchable supercharger driven through a CVT. An initial investigation using this system in place of a variable geometry turbocharger on an already downsized passenger car diesel engine demonstrated greatly increased low speed torque as well as improved dynamic response. A downsizing project that involved replacing a naturally aspirated gasoline engine with a highly boosted engine with 40% of the original displacement formed the basis for more extensive investigations. Although it was unable to produce the low speed transient response of the naturally aspirated engine, in tip-in tests the CVT-supercharger system was shown to achieve the target torque much quicker than an equivalent system with a fixed supercharger drive ratio. However, balancing this with good fuel efficiency for the initial part load period was a complex trade-off. In vehicle acceleration simulations the CVT-supercharger system did not outperform the fixed drive ratio configuration, but on the CVT system the boost limit was reached at an early stage during the transients. Thus there may be potential to include an ‘over-boost’ facility, allowing boost pressure to temporarily exceed normal steady state limits in order to improve transient performance and bring it closer to that of the baseline vehicle. It is suggested that the CVT-supercharger provides the best flexibility for calibration and compromise between performance and fuel efficiency, perhaps incorporating different user-selectable modes (such as ‘economy’ and ‘sport’ modes).

A rápida evolução do mercado automotivo, em função de maiores restrições sobre as emissões, impulsionou a utilização de várias alternativas para melhorias dos motores diesel, entre elas as mudanças nos seus componentes com o auxílio de ferramentas de modelagem e a utilização de combustíveis alternativos. As características dos combustíveis afetarão a queima e, assim, alteram os resíduos do processo de combustão. Novos combustíveis podem também ser utilizados como uma alternativa para veículos de gerações anteriores com o intuito de reduzir as emissões. Este estudo mostra os efeitos da utilização do Biodiesel B20 e do Biodiesel Amyris em motores de combustão interna. Para isso, foram realizados testes de motores em salas dinamométricas, e seus resultados confrontados e discutidos. Além disso, são abordados os efeitos do combustível no processo da combustão. Esta Dissertação está concentrada, principalmente, na emissão de NOx e de material particulado, que são poluentes mais restritivos perante a Legislação brasileira de emissões CONAMA P7. / The fast evolution of the automotive market, in light of the more restrictive emissions requirements, spurred several alternatives for improvements of diesel engines; among them, changes in the engine components with the aid of modeling tools and use of alternative fuels. The fuel characteristics will affect the combustion and thus combustion process residues. New fuels also can be an alternative for vehicles of previous generations of emissions, aiming of reducing them. This study shows the effects of the B20 biodiesel and Amyris biodiesel in diesel engines. Engine tests were held in dynamometric testing cells and their results were compared and discussed. The effects of the different fuels in the combustion process are also discussed. This work is focused mainly in NOx (nitrogen oxide) and particulate matter emissions, which are more restrictive pollutants regarding the Brazilian emissions legislation CONAMA P7.

The automated testing of internal combustion engines is a field of considerable importance. This thesis describes a novel area in the form of dynamic testing. The investigation represents an original approach to the problem with which the author believes he has developed a new concept in engine testing. The resulting information, combined with an appreciation of the latest developments in automation equipment technology, has lead to a review of the requirements of a generalised engine test system together with an outline of the way in which it could be implemented. The automated engine test beds used during the work are described. The conventional methods of testing internal combustion engines are reviewed and a generalised approach to automating them proposed. This then leads to the suggestion of a new method using dynamic testing techniques specially evolved in the course of the work. On the basis of this the implementation of a dynamic full-load power curve as a replacement for its steady state equivalent was pursued. The second major use of dynamic techniques is for exhaust emission cycles. Both dynamic (USEPA Smoke Cycle) and steady-state (USEPA 13 Mode Cycle) cycles were performed. In the case of the former, outer digital loop techniques were used to improve control response. In performing the above work, use was made of both analog and digital simulation techniques for development purposes. This work was also extended by the development of a simulation of a material handling system to enable the control and optimisation of a production test facility to be studied. The testing methods associated with automated fault diagnosis are also analysed. On the basis of the above work an engine test system task analysis was generated and this new concept used to plan a microprocessor based engine test automation scheme.

The widespread use of finite element models in assessing system dynamics for noise, vibration, and harshness (NVH) evaluation has led to recognition of the need for improved procedures for correlating models to experimental results. This study develops and applies a methodology to correlate an experimental modal analysis with a finite element modal analysis of valve trains in IC-engines. A pre-test analysis procedure is employed to guide the execution of tests used in the correlation process. This approach improves the efficiency of the test process, ensuring that the test article is neither under nor over-instrumented. The test-analysis model (TAM) that results from the pre-test simulation provides a means to compare the test and the model both during the experimental approach and during the model updating process. The validity of the correlation methodology is demonstrated through its application on the valve train of a single overhead cam (SOHC) engine.

O conceito de um motor rotativo de palhetas é apresentado e o modelo que opera similar aos motores recíprocos dois tempos é analisado. Este motor é formado por estator cilíndrico, rotor descentralizado, palhetas radiais e tampas laterais, similar aos compressores de palhetas radiais. Parâmetros geométricos estão definidos para que o motor possua características similares a dois motores recíprocos comerciais igualmente modelados. Suas geometrias estão detalhadas, assim como a modelagem termodinâmica e suas hipóteses, as quais devido ao caráter comparativo do trabalho não têm grande influência no alcance dos objetivos. Em relação aos motores recíprocos, o novo conceito prospecta algumas vantagens: maior compacidade; menor nível de vibrações; maior facilidade de alteração da razão de compressão; possibilidade de produção e montagem em módulos; e devido a todas estas, as maiores possibilidades para o projeto, fabricação, montagem e operação dos motores. Para melhor entendimento de algumas tendências relativas a estas vantagens, a sensibilidade dos parâmetros geométricos é estudada, com variações nos diâmetros do estator e do rotor, na espessura do rotor e das palhetas, na excentricidade entre rotor e estator, e no número de palhetas do conceito. Este estudo demonstra características únicas do motor rotativo de palhetas, dentre elas, a variação da espessura do rotor se destaca por proporcionar a alteração do tamanho do motor sem modificar os demais aspectos. A excentricidade entre o rotor e estator demonstra grande potencial na capacidade de alterar a razão de compressão do equipamento, inclusive podendo ser modificada após a construção do motor ou até mesmo durante sua operação. Também se destaca o número de palhetas, o qual tem influência direta sobre a curva de torque do ciclo e a efetividade do posicionamento das janelas de admissão e exaustão. Com isto, é concluída a caracterização da geometria e do funcionamento do motor rotativo de palhetas, obtendo uma boa base para as próximas etapas de seu desenvolvimento. / The concept of a rotary vane engine is presented and the model that operates similar to twostroke reciprocating engines is analyzed. This engine is formed by a cylindrical stator, decentralized rotor, radial vanes and side housing plates, similar to the radial vane compressors. Geometrical parameters are defined so that the motor has similar characteristics to two commercial reciprocating engines also modeled. Their geometries are detailed, as well as the thermodynamic model and its assumptions, which due to the comparative nature of the work do not have significant influence in achieving the objectives. With respect to reciprocating engines, the new concept is prospecting some advantages: higher compactness; lowest level of vibration; ease of adjustment of compression ratio; possibility of manufacture and assembly in modules; and due to all these, the numerous possibilities to the design, manufacture, assembly and operation of the engines. For a better understanding of some these advantages trends, the sensitivity of geometric parameters are studied, with variations in the diameters of the stator and rotor, in the thickness of the rotor and the vanes, in the eccentricity between rotor and stator, and in the number of vanes of the concept. This study demonstrates unique rotary vane engine characteristics, among them, the range of rotor thickness stands out for providing a change in engine size without changing other aspects. The eccentricity between the rotor and stator shows great potential for the ability to change the compression ratio of the equipment and can be modified even after the construction or even during operation of the engine. It also highlights the number of vanes, which has a direct influence on the torque curve of the cycle and the effectiveness of the positioning of inlet and exhaust ports. Therewith, the characterization of rotary vane engine geometry and operational design is complete, obtaining a good basis for its next development stages.