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Abstract(s)
Os motores a pistão implementados na indústria automóvel, dos motociclos e da aviação, têm vindo a sofrer progressivos avanços tecnológicos no decorrer das últimas décadas. Estes são introduzidos com o objetivo de tornar os veículos mais económicos, eficientes, menos poluentes e que ao mesmo tempo apresentem um incremento considerável na potência produzida. Uma das medidas que mais se destacou terá sido a crescente implementação do controlo eletrónico de diversos componentes do motor nos anos 80, mais especificamente a nível do sistema de injeção de combustível e de ignição da mistura ar-combustível. Esta dissertação engloba todo o processo de conceção e fabricação de um corpo de acelerador e respetivo adaptador, com base em componentes já existentes. Estes funcionam como base para efetuar a transição, num motor monocilíndrico de baixa cilindrada, de um sistema de alimentação por carburador para um com injeção eletrónica de combustível. É igualmente concebido um mecanismo de medição de binário e de adaptação de uma hélice ao volante do motor. Os componentes projetados, em conjunto com outros auxiliares, permitiram realizar um estudo que teve como base analisar, registar e comparar a performance de um motor Honda GX31, com recursos a diversos sensores e atuadores, em três configurações diferentes, uma com carburador, outra com o sistema de injeção eletrónica e, por último, outra com injeção e ignição eletrónica aplicadas em simultâneo. A avaliação da performance é feita tendo em consideração a aplicação de uma carga aproximadamente constante e de diferentes regimes de funcionamento, onde para alguns dos quais os mapas da eficiência volumétrica e do ângulo de avanço à ignição são otimizados. A análise numérica consistiu na leitura do binário, através de uma célula de carga, e do consumo de combustível, a partir dos quais é possível calcular outras grandezas, tais como a potência efetiva, o consumo específico e rendimento. Grande parte do processo de afinação e de recolha dos dados obtidos, foi realizado com recurso a um controlador MegaSquirt MS-II e aos softwares TunerStudio MS e MegaLogViewer. Pretende-se portanto evidenciar as vantagens/desvantagens que a implementação de cada um dos sistemas controlados eletronicamente traz ao ramo dos motores de combustão interna a 4 tempos e de pequena cilindrada, focando também todo o processo computacional e base teórica envolvidos em torno da manipulação e otimização dos regimes de funcionamento. As incertezas experimentais são identificadas e quantificadas, e são propostos trabalhos futuros e melhoramentos de componente prática e teórica.
The piston engines implemented in the automotive, motorcycle and aviation industries have been undergoing progressive technological advances over the last decades. These are introduced with the aim of turning vehicles more economical, efficient, less polluting and at the same time presenting a considerable increase in the power produced. One of the measures that stood out the most was the implementation of electronic control of several engine components in the 1980s, more specifically in the systems of fuel injection and ignition of the air-fuel mixture. This dissertation encompasses the whole process of designing and manufacturing a throttle body and its respective adapter, based on existing components. These components work as a basis for the transition, in a low-displacement single-cylinder engine, from a carburetor-fed system to an electronic fuel injection system. It is also conceived a mechanism for measuring torque and adapting a propeller to the flywheel of the engine. The components designed, together with other auxiliaries, allowed the accomplishment of a study to analyze, record and compare the performance of a Honda GX31 engine, with the resource to several sensors and actuators, in three different configurations, one with carburetor, other with the electronic injection system and another with electronic injection and ignition applied simultaneously. Performance evaluation was made having in consideration the application of an approximately constant load and different operating regimes, where for some of them the maps of the volumetric efficiency and ignition advance angle are optimized. The numerical analysis consisted of the reading of torque, through a load cell, and fuel consumption, from which is possible to calculate other quantities, such as effective power, specific consumption and efficiency. Much of the tuning and data collection process was performed using a MegaSquirt MS-II controller and the TunerStudio MS and MegaLogViewer software’s. This work aimed to highlight the advantages/disadvantages that the implementation of each of the electronically controlled systems brings to the field of 4-stroke and small displacement internal combustion engines, also focusing the entire computational process and theoretical basis around the handling and optimization of operating regimes. Experimental uncertainties are identified and quantified, and future works and practical and theoretical improvements are proposed.
The piston engines implemented in the automotive, motorcycle and aviation industries have been undergoing progressive technological advances over the last decades. These are introduced with the aim of turning vehicles more economical, efficient, less polluting and at the same time presenting a considerable increase in the power produced. One of the measures that stood out the most was the implementation of electronic control of several engine components in the 1980s, more specifically in the systems of fuel injection and ignition of the air-fuel mixture. This dissertation encompasses the whole process of designing and manufacturing a throttle body and its respective adapter, based on existing components. These components work as a basis for the transition, in a low-displacement single-cylinder engine, from a carburetor-fed system to an electronic fuel injection system. It is also conceived a mechanism for measuring torque and adapting a propeller to the flywheel of the engine. The components designed, together with other auxiliaries, allowed the accomplishment of a study to analyze, record and compare the performance of a Honda GX31 engine, with the resource to several sensors and actuators, in three different configurations, one with carburetor, other with the electronic injection system and another with electronic injection and ignition applied simultaneously. Performance evaluation was made having in consideration the application of an approximately constant load and different operating regimes, where for some of them the maps of the volumetric efficiency and ignition advance angle are optimized. The numerical analysis consisted of the reading of torque, through a load cell, and fuel consumption, from which is possible to calculate other quantities, such as effective power, specific consumption and efficiency. Much of the tuning and data collection process was performed using a MegaSquirt MS-II controller and the TunerStudio MS and MegaLogViewer software’s. This work aimed to highlight the advantages/disadvantages that the implementation of each of the electronically controlled systems brings to the field of 4-stroke and small displacement internal combustion engines, also focusing the entire computational process and theoretical basis around the handling and optimization of operating regimes. Experimental uncertainties are identified and quantified, and future works and practical and theoretical improvements are proposed.
Description
Keywords
Carga Aproximadamente Constante Controlo Eletrónico Megasquirt Ms-II Motor Monocilíndrico Otimização Performance Transição