Development of Variable Intake System for Spark-Ignition Engine

DEVELOPMENT OF VARIABLE INTAKE SYSTEM FOR SPARK-IGNITION ENGINE

MUHAMMAD HAFIZUDDIN BIN SALIM

Thesis submitted in fulfillment of the requirements for the award of the degree of Bachelor of Mechanical Engineering with Automotive Engineering

Faculty of Mechanical Engineering UNIVERSITI MALAYSIA PAHANG

JUNE 2012 vi

ABSTRACT

This project is to study about the development of variable intake manifold for spark- ignition engine. Variable intake manifold is one of the methods in optimizing the performance of an engine. Some of manufacture have great interest on this system such as Volkswagen and Volvo companies. Further research was held by those companies. Each of them has different in design in order to race in technology of engine optimizing. This experiment was conducted by using flow bench that test on the flow rate of the new design intake manifold that has been fabricated. The test is on the intake manifold that is used by the 1600cc engine. Two intake manifolds were tested in this experiment, the Proton Waja intake manifold and the custom intake manifold that has been fabricated. The result found that the length of runner does affect the flow rate that produced by the intake manifold. The long runner will give better flow rate on the earlier phase of engine speed while the shorter runner will give better flow rate on the top end of engine speed. That is the reason why the variable intake manifold is better intake manifold compared to the standard intake manifold because it can be switch for the suitable length of runner depends on the engine speed condition.

vii

ABSTRAK

Projek ini merupakan kajian mengenai pembuatan “Variable Intake Manifold” untuk enjin yang mengunakan sistem penyalaan pencucuh. “Variable Intake Manifold” merupakan salah satu kaedah dalam mengoptimumkan prestasi enjin. Beberapa syarikat pembuatan sangat berminat ke atas teknologi ini seperti syarikat Volkswagen dan Volvo. Mereka banyak melanjutkan kajian terhadap teknologi ini. Setiap pembuatan yang dilakukan sering berbeza dari segi reka bentuk didalam perlumbaan teknologi mengoptimumkan enjin ini. Ekseperimen in dilakukan dengan menggunakan bangku aliran bagi mengetahui kadar aliran yang terhasil daripada “intake manifold” itu tadi. Ujian yang dilakukan adalah berdasarkan enjin berkapasiti 1600cc. Dua “intake manifold” yang di uji di dalam eksperimen ini iaitu bagi penggunaan Proton Waja dan juga “intake manifold” yang telah di buat. Hasilnya didapati bahawa panjang pelari sememangnya mempengaruhi kadar aliran yang dihasilkan oleh “intake manifold”. Pelari yang panjang akan memberikan kadar aliran yang lebih baik pada fasa awal kelajuan enjin manakala pelari yang pendek akan memberikan kadar aliran yang lebih baik di hujung fasa kelajuan enjin. Disebabkan itu “Variable Intake Manifold” lebih baik berbanding “intake manifold” biasa kerana ia boleh mengubah laluan aliran mengikut kesesuaian kelajuan enjin.

viii

TABLE OF CONTENT

ITEMS PAGE

SUPERVISOR’S DECLARATION ii STUDENT’S DECLARATION iii DEDICATION iv ACKNOWLEDGEMENTS v ABSTRACT vi ABSTRAK vii TABLE OF CONTENTS viii LIST OF TABLES xi LIST OF FIGURES xii

CHAPTER 1 INTRODUCTION

1.1 Project Background 1 1.2 Problem Statement 2 1.3 Objectives 2 1.4 Scopes of Project 3

CHAPTER 2 LITERATURE REVIEW

2.0 Introduction 4 2.1 Internal Combustion Engine Principle Operation 5 2.1.1 Spark Ignition Engine 5 2.1.2 Homogeneous Charge SI Engine 6 2.1.3 Basics of 4-Stroke Homogeneous SI Engine 6 2.2 Air Intake System 7 2.2.1 Air Intake Filter 8 2.2.2 Turbocharging 9 ix

2.2.3 Intake Manifold 10 2.2.4 Variable Intake Manifold 12 2.2.5 Principles Of Variable Resonance Intake Manifold Operation 13 2.2.6 Intake Manifold Design 19

2.3 Air Intake System Optimization Effect 20 2.3.1 Fuel Consumption 21 2.3.2 Engine Performance 23

2.4 Theory of Dynamics 25 2.4.1 Wave Theory 25 2.4.2 Fluid Flow 27 2.4.3 Design Equation 28 2.4.4 Gas Dynamics 29 2.4.5 Steady Flow 30 2.4.6 Turbulence 32 2.4.7 Ideal Gas law 33 2.4.8 Volumetric Efficiency 34 2.4.9 Intake Manifold Pressure 34 2.4.10 Conservation of Energy 35

2.5 Previous System Benchmarking 35

2.6 Air Intake System Leakages 37

2.7 Swirl Effect 38

2.8 3-D CFD Analyses 39

2.9 Summary 40

CHAPTER 3 METHODOLOGY

3.1 Introduction 41 3.2 Method Flow Chart 42 3.3 Manifold Design 43 3.4 Material Selection 44 3.5 Fabrication 45 3.6 Experiment 46 3.6.1 Reference Engine 46 3.6.2 Acrylic Cylinder Block 46 3.6.3 Experimental Set up 47 x

3.6.4 Experiment process 48 3.6.5 Experiment Procedure 50

CHAPTER 4 RESULT AND ANALYSIS

4.1 Introduction 52 4.2 Result 52 4.2.1 Flow Test Result 53 4.3 Analysis 56

4.3.1 Constant test pressure equal to 50 cmH2O and single valve lift 57 4.3.2 Constant valve lift condition (double) 58 4.3.3 Constant test pressure equal to 10 cmH2O and single valve lift 60 4.3.4 Constant test pressure equal to 50 cmH2O and double valve lift 61 4.3.5 Constant test pressure equal to 50 cmH2O and short runner 62

CHAPTER 5 CONCLUSIONS AND RECOMMENDATIONS

5.1 Introduction 63 5.2 Conclusions 63 5.3 Recommendations 64

REFFERENCES 66

APPENDICES A1 2002 Honda F4i Engine Specifications 70 A2 Minimum mechanical properties* of steel pipes 71 A3 SuperFlow SF-1020 specification 72 B1 Gantt chart 73 B2 Flow coefficient graph 74 B3 Round hollow mild steel 75 B4 Fabrication process figures 76

LIST OF TABLES

Table No. Title Page 2.1 2002 Honda F4i Engine Specifications 70 2.2 Intake and exhaust characteristic of previous system 36 2.3 Summary of previous Driver’s experience with past 36 intake system 3.1 Mitsubishi 4G18 engine specification 46 3.2 Minimum mechanical properties* of steel pipes 71 3.3 SuperFlow SF-1020 specification 72 4.1 Runner characteristic 52 4.2 Flow tests result for head cylinder 53 4.3 Flow test 1 results for head cylinder with standard intake 53 manifold 4.4 Flow test 2 results for head cylinder with standard intake 54 manifold 4.5 Flow test 3 results for head cylinder with standard intake 54 manifold 4.6 Flow test 1 results for head cylinder with variable intake 55 manifold 4.7 Flow test 2 results for head cylinder with variable intake 55 manifold 4.8 Flow test 3 results for head cylinder with variable intake 56 manifold

xii

LIST OF FIGURES

Figure No. Title Page 1.1 Gantt chart for semester 1 73 1.2 Gantt chart for semester 2 73 2.1 Schematic diagram of spark ignition engine 5 2.2 Four-Stroke Combustion Cycle 6 2.3 Turbocharging mechanism 9 2.4 Basic Intake Manifold Diagram 11 2.5 Component modeling flow 12 2.6 Volkswagen variable intake manifold 13 2.7 Intake manifold diagram operation 1 14 2.8 Intake manifold diagram operation 2 14 2.9 Intake manifold diagram operation 3 15 2.10 Intake manifold diagram operation 4 16 2.11 Intake manifold diagram operation 5 17 2.12 Intake manifold diagram operation 6 18 2.13 Intake manifold diagram operation 7 18 2.14 Intake manifold diagram operation 8 19 2.15 Basic fuel consumption graph 21 2.16 Variation of fuel consumption with engine speed for three 22 different intake plenum volumes 2.17 Brake torque graph 23 2.18 Torque – RPM and plenum volume sweep 24 2.19 Comparison of torque between smallest and largest 25 plenums tested 2.20 Schematic representation of wave action in the inlet 26 manifold 2.21 Velocity profiles within a pipe 28 2.22 Transition between laminar and turbulent flow 32 2.23 Spiral-tangential swirl pattern 38 2.24 3-D CFD simulation (swirl pattern) 40 2.25 Flow Coefficient Graph 74 xiii

3.1 Method flow chart 42 3.2 Performance intake manifold 43 3.3 Proton Waja 1.6 SOCH intake manifold 44 3.4 Acrylic block cylinder for 1600cc 46 3.5 Flow bench 47 3.6 Flow bench data screen 48 3.7 Dial gauge position 48 3.8 Experiment diagram 49 3.9 Standard intake manifold test 50 3.10 V