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Advisor(s)
Abstract(s)
Nos nossos dias, as alterações climáticas são uma das principais temáticas. Por esse motivo o
mundo está a ser desafiado a mudar os seus comportamentos.
Os automóveis são um dos responsáveis para o aumento do efeito de estufa. Assim sendo, temse de desenvolver novos mecanismos mais eficientes. Nestes mecanismos encontra-se a árvore
de cames.
A árvore de cames é um elemento que faz acionar as válvulas que permite a entrada de ar e
saída de gases pelo escape. Ao se modificar a árvore de cames do motor Honda GX160 pretendese seja mais eficiente, bem como consuma menos combustível. O objetivo da alteração é fechar
a válvula de admissão mais cedo. Para isso teve-se de desenvolver as curvas que representam
as o deslocamento, velocidade e aceleração.
Ao serem modificadas as curvas pretende-se que que ocorra uma transformação de um ciclo de
Otto num ciclo de Miller.
A came de admissão foi submetida a simulações numéricas para se conhecer para conhecer as
forças resultantes no mecanismo. Além das forças também se conseguiu saber a tensão que a
came provocará no seguidor.
Finalmente realizou-se ensaios práticos. Estes ensaios tiveram por base verificar se a entrada
de ar no motor seria reduzido.
Este projeto teve o intuito de ser utilizado na competição Shell Eco Marathon.
Nowadays, climate change is one of the main concerns worldwide. Therefore, the world is being challenged to alter its behaviours. Automobiles/cars are one of the main culprits regarding the increase of greenhouse effects. Hence, it is of the utmost importance to develop new and more effective mechanisms. Among these mechanisms, we single out the camshaft. The camshaft is the component which triggers the valves, allowing the entry and exiting of gases through the exhaust valve. By altering the camshaft from the Honda GX160 motor, it is aimed to be more efficient, as well as, to consume less fuel. The goal of this change is to close the admission valve earlier. Do to so, it was necessary the development of curves/graphs, which represent the displacement, velocity and acceleration. By changing the curves, it is intended to transform an Otto Cycle into a Miller Cycle. The admission cam was subjected to numerical simulations to get to know the resulting forces on the mechanism. Besides the forces, it was also possible to understand the tension the cam will produce in the follower. Finally, trials were performed. These trials had as an objective to check whether the entry of air into the engine was reduced. This project has the intent of being used in the Shell Eco Marathon competition.
Nowadays, climate change is one of the main concerns worldwide. Therefore, the world is being challenged to alter its behaviours. Automobiles/cars are one of the main culprits regarding the increase of greenhouse effects. Hence, it is of the utmost importance to develop new and more effective mechanisms. Among these mechanisms, we single out the camshaft. The camshaft is the component which triggers the valves, allowing the entry and exiting of gases through the exhaust valve. By altering the camshaft from the Honda GX160 motor, it is aimed to be more efficient, as well as, to consume less fuel. The goal of this change is to close the admission valve earlier. Do to so, it was necessary the development of curves/graphs, which represent the displacement, velocity and acceleration. By changing the curves, it is intended to transform an Otto Cycle into a Miller Cycle. The admission cam was subjected to numerical simulations to get to know the resulting forces on the mechanism. Besides the forces, it was also possible to understand the tension the cam will produce in the follower. Finally, trials were performed. These trials had as an objective to check whether the entry of air into the engine was reduced. This project has the intent of being used in the Shell Eco Marathon competition.
Description
Keywords
Árvore de Cames Came de Admissão Motores de Combustão Interna Ubicar Válvula