Design of the Valve Actuation Mechanism of a Four-Stroke Spark Ignition Internal Combustion

115 Pages·2016·27.47 MB·English

DEPARTAMENTO DE
ENGENHARIA MECÂNICA

Design of the Valve Actuation Mechanism of a
Four-Stroke Spark Ignition Internal Combustion
Engine
Submitted in Partial Fulfillment of the Requirements for the Degree of Master in
Mechanical Engineering in the specialty of Energy and Environment

Selecção e Dimensionamento de um Mecanismo de
Accionamento de Válvulas de um Motor de
Combustão Interna de Ciclo de 4 Tempos de Ignição
por Faísca

Author
Francisco José Queirós Capela de Vieira e Brito
Advisor
Professor Doutor Pedro de Figueiredo Vieira Carvalheira

Jury
Professor Doutor José Manuel Baranda Moreira da Silva
President Ribeiro
Professor Auxiliar da Universidade de Coimbra
Professor Doutor Fernando Jorge Ventura Antunes
Professor Auxiliar da Universidade de Coimbra
Vowels
Professor Doutor Pedro de Figueiredo Vieira Carvalheira
Professor Auxiliar da Universidade de Coimbra
Professor Doutor Pedro de Figueiredo Vieira Carvalheira
Advisor
Professor Auxiliar da Universidade de Coimbra

Coimbra, July, 2016

With your mind power, your determination, your instinct, and the experience as
well, you can fly very high.
Ayrton Senna, in “Racing is in My Blood”, 1991.

To my Parents and Joana.

Acknowledgements

ACKNOWLEDGEMENTS
This dissertation would not be possible without all the support I received. I
would like to take this opportunity and repay some of that gratitude.
To my Advisor, Professor Doutor Pedro Carvalheira. For the incredible support,
availability and concern from the first moment, but also for teaching me so much in such a
short span of time. I could not have hoped for a better advisor. Thank you very much
Professor.
To my Parents. Not only for supporting me all of the time and allowing me to
pursue my dreams, but also for being a daily inspiration and a true example that belief and
hard work can accomplish anything. Thank you so much.
To Joana. For being everything I could ask for and more. For the incredible
support in every second I need it and for encouraging me to be better every single day. Thank
you so much.

Francisco José Queirós Capela de Vieira e Brito iii
Design of the Valve Actuation Mechanism of a Four-Stroke Spark Ignition Internal Combustion
Engine

iv 2016
Abstract

Abstract
The goal of this work is to design the valve actuation mechanism of a naturally
aspirated, four-stroke, spark ignition internal combustion engine, for an urban vehicle. The
engine has a 1.0-liter displacement volume, three cylinders inline, with four valves per
cylinder and port fuel injection.
The work began by performing numerical simulations using software developed
at DEM-FCTUC [1]. This software models the engine cycle to determine the valve lift and
valve opening and closing angles. The simulations are performed in the engine torque and
speed domain of use, for the functional requirements of the engine. Two architectures of the
valve actuation mechanism were defined. The kinematic and dynamic studies were then
made, and the friction power of the two mechanisms, as a function of engine speed, was
evaluated. Afterwards the architecture was selected. The following components of the
actuation mechanism were object of detailed design in Autodesk Inventor 2016: intake and
exhaust valves, intake and exhaust valve springs, bucket tappets, valve retainers, valve
keepers, valve beads, valve guides and valve seats.

Keywords Engine, Valve, Variable, Lift, Intake, Exhaust, Bucket
Tappet, Finger Follower, Mechanism.

Francisco José Queirós Capela de Vieira e Brito v
Design of the Valve Actuation Mechanism of a Four-Stroke Spark Ignition Internal Combustion
Engine

vi 2016
Resumo

Resumo
A motivação para este trabalho consiste em efetuar a seleção e o projeto
detalhado de um mecanismo de acionamento de válvulas de um motor de combustão interna,
de ciclo de quatro tempos e ignição por faísca, para um veículo automóvel utilitário. O motor
tem 1.0 litro de cilindrada, três cilindros em linha, quatro válvulas por cilindro e injeção na
porta de admissão.
O trabalhou começou pela realização de simulações de modelação do ciclo de
funcionamento do motor, usando o programa “Ciclo de Funcionamento do Motor”
desenvolvido no DEM-FCTUC [1], para determinar o levantamento máximo e os ângulos
de abertura e fecho das válvulas de admissão e escape em função da velocidade de rotação
do motor. Foram definidas duas arquiteturas para o trem de válvulas, efetuados estudos
cinemáticos e dinâmicos e avaliado o atrito de ambos os mecanismos em função da
velocidade de rotação do motor. De seguida foi efetuada a seleção da arquitetura mais
adequada, em função dos requisitos funcionais do mesmo. Os componentes seguintes do
mecanismo de acionamento das válvulas do motor foram objeto de desenho pormenorizado
em software de desenho CAD-3D (Autodesk Inventor 2016): válvulas de admissão e de
escape, molas das válvulas de admissão e escape, touches, retentores das válvulas, pratos
das válvulas, meias-luas, guias das válvulas e sedes das válvulas.

Palavras-chave: Motor, Válvula, Variável, Levantamento, Admissão,
Escape, Touche, Balanceiro, Mecanismo.

Francisco José Queirós Capela de Vieira e Brito vii
Design of the Valve Actuation Mechanism of a Four-Stroke Spark Ignition Internal Combustion
Engine

viii 2016