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Advisor(s)
Abstract(s)
O mecanismo mais popularmente aplicado em motores de combustão interna é o bielamanivela,
utilizado para converter o movimento alternativo do pistão em movimento rotativo
no veio de saída. O conceito hipocicloide adaptado a um motor de combustão interna, com
engrenagens em vez do mecanismo biela-manivela, apresenta-se como uma alternativa viável
ao motor tradicional. O mecanismo hipocicloide com engrenagens permite o movimento linear
do conjunto biela-pistão e reduz as vibrações.
Do esforço da investigação neste campo, uma grande variedade de projetos de motores
hipocicloides têm sido realizados e construídos protótipos com sucesso. Estes estudos
mostraram que o mecanismo hipocicloide apresenta melhorias no rendimento, em relação ao
convencional biela-manivela. Contudo, a configuração hipocicloide ainda não foi capaz de se
impor no mercado, apesar das suas inúmeras vantagens, desde a redução de atrito, vibrações,
massa e anulação das forças laterias.
Pretende-se com este trabalho avaliar e otimizar o protótipo de um motor com mecanismo
hipocicloide, por forma a maximizar o seu desempenho. O protótipo desenvolvido com base em
estudos anteriormente efetuados foi desenhado e testado em CAD. Simulações de modelos
matemáticos para ambos os mecanismos de motores (hipocicloide e biela-manivela) foram
usadas para quantificar as melhorias de desempenho. O desempenho deste motor foi calculado
e comparado com os dados obtidos para um motor de combustão interna convencional da
mesma dimensão - 25 cm3.
Este trabalho comprova as conclusões obtidas nos estudos anteriormente efetuados, presentes
no estado da arte. Nos testes de simulação foi possível verificar uma resposta mais rápida do
motor com sistema hipocicloide em relação ao motor tradicional, isso verifica-se no aumento
de trabalho produzido de 0,73%.
The most common mechanism applied for internal combustion engines is the slide-crank system and is used to convert the reciprocating motion of the piston into rotary motion of output shaft. The hypocycloid concept adapted to an internal combustion engine (with gears instead of the slide-crank mechanism) presents itself as a viable alternative to a traditional engine. This concept with gears allows the rod-piston unit to move linearly and reduces vibrations significantly. A wide range of hypocycloid engine designs have been carried out and the research effort in this field as come to a series of successfully prototypes. These studies showed that the hypocycloid mechanism offers improvements in performance when compared to the conventional rod-crank mechanism. However, the hypocycloid configuration has not yet been able to prove itself on the market despite its numerous benefits - from reducing friction, vibration, mass and cancellation of laterals forces. The aim of this work is to evaluate and optimize a prototype engine with hypocycloid mechanism in order to take full advantage of its performance. The developed prototype is based on previously conducted studies and it was designed and tested in CAD. Mathematical models simulations for both engines mechanisms (hypocycloid and slide-crank) were used to quantify performance improvements. The performance of this engine was calculated and compared with the data obtained for a conventional internal combustion engine of the same size - 25 cm3. This work confirms the conclusions reached in previous studies made on the state of the art. On the simulation tests it was possible to notice a faster motor response with the hypocycloid system compared to the traditional engine – the work produced increased 0.73%.
The most common mechanism applied for internal combustion engines is the slide-crank system and is used to convert the reciprocating motion of the piston into rotary motion of output shaft. The hypocycloid concept adapted to an internal combustion engine (with gears instead of the slide-crank mechanism) presents itself as a viable alternative to a traditional engine. This concept with gears allows the rod-piston unit to move linearly and reduces vibrations significantly. A wide range of hypocycloid engine designs have been carried out and the research effort in this field as come to a series of successfully prototypes. These studies showed that the hypocycloid mechanism offers improvements in performance when compared to the conventional rod-crank mechanism. However, the hypocycloid configuration has not yet been able to prove itself on the market despite its numerous benefits - from reducing friction, vibration, mass and cancellation of laterals forces. The aim of this work is to evaluate and optimize a prototype engine with hypocycloid mechanism in order to take full advantage of its performance. The developed prototype is based on previously conducted studies and it was designed and tested in CAD. Mathematical models simulations for both engines mechanisms (hypocycloid and slide-crank) were used to quantify performance improvements. The performance of this engine was calculated and compared with the data obtained for a conventional internal combustion engine of the same size - 25 cm3. This work confirms the conclusions reached in previous studies made on the state of the art. On the simulation tests it was possible to notice a faster motor response with the hypocycloid system compared to the traditional engine – the work produced increased 0.73%.
Description
Keywords
Mecanismo Bielamanivela Mecanismo Hipocicloide Motor de Combustão Interna Rodas Dentadas