Preparação de um motor para competição automóvel
Data
2017-12-20
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O presente trabalho tem como objetivo o estudo da preparação de um motor de combustão interna com o objetivo de o preparar para a competição automóvel. Este trabalho foi desenvolvido no âmbito de um estágio realizado na empresa Garagem Aurora, especialista em alteração e preparação de automóveis para o domínio de competição. Na competição automóvel, os automóveis têm de garantir determinadas caraterísticas, entre as quais, a garantia de se propulsionarem a elevadas velocidades, num curto período de tempo, sendo para tal necessário realizar alterações no motor do automóvel. Para a realização destas alterações, é necessário aplicar técnicas avançadas e conhecimentos em diversas áreas, tais como Termodinâmica, Mecânica Aplicada e Mecânica de Fluídos, Órgãos de Máquinas, Vibrações, entre outros, para que assim se consiga alcançar o objetivo de possuir um motor competitivo e fiável. Foram realizadas diversas alterações no motor original de um Porsche 911 SC, com a finalidade de incrementar o seu rendimento, assim como, o desempenho para a competição automóvel. Para obter tal desiderato, foram efetuados os cálculos relativos às alterações efetuadas no motor, comparando sempre os resultados obtidos no motor alterado com os obtidos no motor de origem. Assim, foi possível estabelecer relações e retirar conclusões com as alterações promovidas no motor. As alterações efetuadas no motor resultaram em vantagens e desvantagens, quando comparado com o motor de origem. Assim, o motor alterado possui mais potência e binário específico do que o motor de origem, cerca de 114cv e 53N.m respetivamente, bem como uma gama de rotação mais ampla cerca de 8000 rpm quando comparada com as 6700 rpm do motor original. Desta forma, o motor alterado é capaz de impulsionar o veículo a maiores velocidades, bem como operar em regimes de rotação mais elevados do que o motor de origem. Porém, as alterações trouxeram algumas desvantagens ao motor alterado tais como, pressão média efetiva mais elevada, consumos de combustível mais elevados, para valores compreendidos entre os 35l/100km e os 40l/100km e potências de perdas maiores quando comparado com o motor de origem. Estas desvantagens traduzem maior desgaste para o motor alterado quando comparado com o motor de origem. Porém, o aumento do consumo de combustível está associado ao aumento da potência efetiva e do binário efetivo verificado no motor alterado. Foi assim obtido um motor competitivo, capaz de impulsionar o automóvel a velocidades superior e num menor espaço de tempo, resultando também num motor fiável, resistindo a um funcionamento constante no seu regime máximo.
The present work has the objective of studying the preparation of an internal combustion engine destined to the automobile competition. This work was developed during a stage realized in the company Garagem Aurora, specialist in alteration of automobiles for motorsport. There is a need to make changes in the car’s engine in order to meet these needs in the automobile competition, the need to have cars capable of driving at high speeds in a short period of time. In order to achieve these changes, it is necessary to apply advanced techniques and knowledge in various areas, such as thermodynamics, applied mechanics and fluid dynamics, so that the goal of having a competitive and reliable engine is achieved. Several changes were made in the original engine of a Porsche 911 SC, in search of having a high performance engine, where it would later be inserted in automobile competition. For this, the calculations were made regarding the changes made in the engine, always comparing the results obtained in the modified engine with the original engine. Thus, it was possible to establish relationships and draw conclusions with the changes promoted in the engine. Changes made to the engine resulted in advantages and disadvantages when compared to the original engine. Thus, the altered engine has more power and specific torque than the original engine, about 114cv and 53N.m respectively, as well as a wider rotational range about 8000 rpm when compared to the original engine’s 6700 rpm. In this way, the altered engine is able to propel the vehicle at higher speeds as well as operate at higher revs than the original engine. However, the changes brought some disadvantages to the altered engine such as higher effective mean pressure, higher fuel consumptions, to values ??between 35l/100km and 40l/100km and higher loss powers when compared to the original engine . These disadvantages translate to increased wear for the altered engine when compared to the original engine. However, the increase in fuel consumption is associated with the increase of the effective power and the effective torque verified in the altered engine. A competitive engine was thus obtained, able to propel the car at higher speeds and in a shorter time, also resulting in a reliable engine, resisting a constant operation at its maximum speed.
The present work has the objective of studying the preparation of an internal combustion engine destined to the automobile competition. This work was developed during a stage realized in the company Garagem Aurora, specialist in alteration of automobiles for motorsport. There is a need to make changes in the car’s engine in order to meet these needs in the automobile competition, the need to have cars capable of driving at high speeds in a short period of time. In order to achieve these changes, it is necessary to apply advanced techniques and knowledge in various areas, such as thermodynamics, applied mechanics and fluid dynamics, so that the goal of having a competitive and reliable engine is achieved. Several changes were made in the original engine of a Porsche 911 SC, in search of having a high performance engine, where it would later be inserted in automobile competition. For this, the calculations were made regarding the changes made in the engine, always comparing the results obtained in the modified engine with the original engine. Thus, it was possible to establish relationships and draw conclusions with the changes promoted in the engine. Changes made to the engine resulted in advantages and disadvantages when compared to the original engine. Thus, the altered engine has more power and specific torque than the original engine, about 114cv and 53N.m respectively, as well as a wider rotational range about 8000 rpm when compared to the original engine’s 6700 rpm. In this way, the altered engine is able to propel the vehicle at higher speeds as well as operate at higher revs than the original engine. However, the changes brought some disadvantages to the altered engine such as higher effective mean pressure, higher fuel consumptions, to values ??between 35l/100km and 40l/100km and higher loss powers when compared to the original engine . These disadvantages translate to increased wear for the altered engine when compared to the original engine. However, the increase in fuel consumption is associated with the increase of the effective power and the effective torque verified in the altered engine. A competitive engine was thus obtained, able to propel the car at higher speeds and in a shorter time, also resulting in a reliable engine, resisting a constant operation at its maximum speed.
Descrição
Dissertação de Mestrado em Engenharia Mecânica