.
. 3‘. «.3.

.

“f...
3 u

s

...: 41. ‘ , , 11‘! .1
‘ g p ”Haw—WWW. .1”...

. < .

:6." H

«may i . a...

l... .
, ...7 m.

T 3:.

,3»me

. , t
, yuan.
..r‘vCfol'
a 5 .\

.
a}!

; A...

... bah
a

5.....-

5.13.2.
.e...

57. A . zit}... r, .

t “Eva“..wxluaéd a 1.? éswwfimm

..
g a... .Nn. :1 $2“... :
. 73...}: .. . x
. ..r..w7.5£nw. . .mrfimm 9.01%?
.. {V

.3

$5. ., g
E"?
.v rm;$

.m

z u.

_.
v... .r.

3

.3 .
at
iv"

v".

. .1:
2%“ .

. , (an A 2
:L . . . ‘ y. «at:
, Jr. D‘Fn.

.. . . _
if: *

.
a...» . a a
"E“ 1W3; .rmn».

.mh i3
_ ‘

9: .ur $5,

.~ T...,

L
kn...

.:
..N‘.

. ”3;?

m.
....
drain

. ~ pm 1

5?

”Tara.

. 90%..) _

sr i
.1... A

..Mx... ...I

a): ..

11
:

riak

$£3‘i‘,§“;‘3r :11;
{31%; 353"»

ll ,
4L1). ’1“

 

"

1px. 3 .2 . .

.. ‘ . s

ifiafil

.L. ..fiin a.

...: in. rt.

.3? 3...,

. . 4L5,
«2:4,»?
lung-5 £1411fini

aam

THESiS

 

 

Z
.ZCJIJi
LIBRARY
Michigan State
University

 

 

This is to certify that the

thesis entitled

ESTABLISHMENT OF CYLINDER KIT DESIGN GUIDELINES
FOR FOUR-STROKE INTERNAL COMBUSTION ENGINES
USING NUMERICAL SIMULATIONS

presented by

Stephen Robert Yen

has been accepted towards fulfillment
of the requirements for

 

 

M. S. degree in Mechanical Engineering

 

Major rofessor

Date /2/0 7/00

0-7 639 MS U is an Affirmative Action/Equal Opportunity Institution

PLACE IN RETURN BOX to remove this checkout from your record.
TO AVOID FINES return on or before date due.
MAY BE RECALLED with earlier due date if requested.

 

DATE DUE

DATE DUE

DATE DUE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11/00 ammonium.“

 

 

ESTABLISHMENT OF CYLINDER KIT DESIGN GUIDELINES FOR
FOUR-STROKE INTERNAL COMBUSTION ENGH‘IES USING NUMERICAL

SIMULATIONS

By

Stephen Robert Yen

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of
MASTER OF SCIENCE

Department of Mechanical Engineering

2000

ABSTRACT

ESTABLISHMENT OF CYLINDER KIT DESIGN GUIDELINES FOR
FOUR-STROKE INTERNAL COMBUSTION ENGINES USING NUMERICAL
SIMULATIONS
By

Stephen Robert Yen

Engine efficiency and emissions performance constraints have motivated the
automotive industry to focus research on piston and piston ring pack design. This thesis
presents guidelines on the practical aspects of cylinder kit geometry that should be
followed to achieve maximum engine performance. Theoretical explanations of why these
designs provide improved performance are also discussed.

Due to the thousands Of engine operating conditions that were tested, the
ring-pack performance estimates could only be found by means of computer Simulation.
The Cylinder kit Analysis System for Engines (CASE) was utilized to obtain the results.

A simple optimizing program was initially written using finite difference
methods. The results of both this program and a previously written (more advanced)
optimizing program showed that the parameter values often lie on the constraints.
Additional analyses were performed and the predicted results showed that many of the
cylinder kit geometries (ring axial width, piston groove height, etc.) have predictable
relationships to the engine performance. These relationships are analyzed in further detail

in this thesis.

This thesis is dedicated to my parents
Robert Yen
&
Mei-Rong Yen

For their love, guidance and motivation

iii

TABLE OF CONTENTS

TABLE OF CONTENTS ................................................................................................... iv
LIST OF TABLES ............................................................................................................ vii
LIST OF FIGURES ......................................................................................................... viii
NOMENCLATURE ........................................................................................................ xiv
CHAPTER 1: INTRODUCTION ........................................................................................ 1
1.1 Overview .................................................................................................................. 1

1.2 Motivation ................................................................................................................ 2
1.2.1 Advantages Over Optimization Program ........................................................ 2

1.2.2 Advantages Over Physical Testing ................................................................. 3

1.3 Objectives ................................................................................................................ 3
CHAPTER 2: FUNDAMENTAL GAS DYNAMICS THEORY ....................................... 4
2.1 Introduction to Gas Flows in Cylinder Kits ............................................................. 4

2.2 Gas Flow Model ....................................................................................................... 5

2.3 Energy Balance ........................................................................................................ 6

2.4 Thermodynamic Gas Model .................................................................................... 8

2.5 Mass Flow Model .................................................................................................... 8

2.6 Numerical Procedure ............................................................................................. 12
CHAPTER 3: RING DYNAMICS THEORY ................................................................... 15
3.1 Introduction to Ring Dynamics .............................................................................. 15

3.2 Ring Forces in Axial Direction .............................................................................. 15
3.2.1 Inertial Force ................................................................................................. 15

3.2.2 Pressure Forces ............................................................................................. 16

3.2.3 Friction Forces .............................................................................................. 16

3.3 Ring Flutter ............................................................................................................ 17

3.4 Ring Collapse ......................................................................................................... 18
CHAPTER 4: COMPUTER SIMULATION VALIDATION ........................................... 22
4.1 Overview ................................................................................................................ 22
4.2 Comparisons .......................................................................................................... 22
4.2.1 Comparing Predicted Blowby Maps ............................................................. 22

4.2.2 Comparing Measured and Predicted Blowby Maps ..................................... 22
CHAPTER 5: COMPUTER SIMULATION SETUP ....................................................... 24
5.1 Simulation Hardware and Software ....................................................................... 24
5.2 Operating Conditions ............................................................................................. 25

iv

5.3 Cylinder Kit Schematics ........................................................................................ 25

5.4 Engines Simulated ................................................................................................. 27

5.5 Gas Pressure Input Data ......................................................................................... 43
5.6 Ring Geometry Input Data ..................................................................................... 44
5.6.1 Primary Parametric Study ............................................................................. 44

5.6.2 Secondary Parametric Study ......................................................................... 45

5.7 Bore, Piston, and Connecting Rod Data ................................................................ 46
5.8 Ring Twist .............................................................................................................. 46
CHAPTER 6: COMPUTER SHVIULATION RESULTS .................................................. 49
6.1 Overview ................................................................................................................ 49
6.2 Plots ....................................................................................................................... 49
CHAPTER 7: COMPUTER SIMULATION ANALYSIS ................................................ 50
7.1 Blowby Map Analysis ........................................................................................... 50
7.2 General Observations ............................................................................................. 51
7.2.1 Effect of Blowby Magnitude on Parameter Sensitivity ................................ 51

7.2.2 Note on Engine Comparisons ....................................................................... 51

7.3 End Gap Analysis .................................................................................................. 52
7.3.1 Mini-Study on 5.4 L V8 Ford Motor Company Engine ............................... 53

7.3.2 Note of Caution ............................................................................................. 55

7.4 Axial Width Analysis ............................................................................................. 55
7.5 Groove Height Analysis ......................................................................................... 56
7.6 Small Clearance Between Top of Ring and Top of Groove .................................. 56
7.7 Radial Thickness Analysis ..................................................................................... 57
7.7.1 Relating Ring Wear to Radial Thickness ...................................................... 58

7.8 Groove Diameter Analysis ..................................................................................... 58
7.8.1 Basic Overview ............................................................................................. 58

7.8.2 Exceptions to the Rule .................................................................................. 58
CHAPTER 8: CONCLUSIONS AND RECOMMENDATIONS ..................................... 60
8.1 General Implications .............................................................................................. 60
8.2 Top Ring Trends .................................................................................................... 60

8.3 HC Emissions ........................................................................................................ 61

8.4 Top and Second Compression Ring Relation ........................................................ 61

8.5 Recommendations .................................................................................................. 61
CHAPTER 9: REFERENCES ........................................................................................... 63
CHAPTER 10: APPENDD( A .......................................................................................... 64
10.1 Note About Blowby Scale ................................................................................... 64
10.2 Parametric Study Plots for Ford 2.3 L 14 Engine ................................................ 64
10.2.1 Original Design .......................................................................................... 65

10.2.2 End Gap Variations .................................................................................... 65

10.2.3 Axial Width Variations .............................................................................. 68

10.2.4 Groove Height Variations .......................................................................... 71

10.2.5 Radial Thickness Variations ...................................................................... 73

10.2.6 Groove Diameter Variations ...................................................................... 76
10.3 Parametric Study Plots for Ford 4.6 L V8 Engine ............................................... 78
10.3.1 Original Design .......................................................................................... 79
10.3.2 End Gap Variations .................................................................................... 79
10.3.3 Axial Width Variation ............................................................................... 84
10.3.4 Groove Height Variation ........................................................................... 87
10.3.5 Radial Thickness Variations ...................................................................... 89
10.3.6 Groove Diameter Variations ...................................................................... 91
10.4 Parametric Study Plots for Ford 5.4 L V8 Engine ............................................... 95
10.4.1 Original Design .......................................................................................... 96
10.4.2 End Gap Variations .................................................................................... 96
10.4.3 Axial Width Variations ............................................................................ 100
10.4.4 Groove Height Variations ........................................................................ 103
10.4.5 Radial Thickness Variations .................................................................... 108
10.4.6 Groove Diameter Variations .................................................................... 112
10.5 Ford 5.4 L V8 Engine Mini-Study ..................................................................... 116

vi

LIST OF TABLES

TABLE 1: Computer Hardware ........................................................................................ 24
TABLE 2: Computer Software ......................................................................................... 24
TABLE 3: Ford 5.4 L V8 2 Valve Cylinder Kit Specifications ....................................... 28
TABLE 4: Ford 4.6 L V8 2 Valve Cylinder Kit Specifications ....................................... 33
TABLE 5: Ford 2.3 L 14 2 Valve Cylinder Kit Specifications ......................................... 38
TABLE 6: Ford 5.4 L V8 Engine Top Compression Ring Test Matrix ........................... 44
TABLE 7: Ford 4.6 L V8 Engine Top Compression Ring Test Matrix ........................... 44
TABLE 8: Ford 2.3 L 14 Engine Top Compression Ring Test Matrix ............................. 45
TABLE 9: Ford 5.4 L V8 Engine Top and Second Compression Ring Test Matrix ........ 45
TABLE 10: Ford 5.4 L V8 Engine Top Piston Groove Test Matrix ................................ 46
TABLE 11: Ford 4.6 L V8 Engine Top Piston Groove Test Matrix ................................ 46
TABLE 12: Ford 2.3 L V8 Engine Top Piston Groove Test Matrix ................................ 46
TABLE 13: Qualitative Parametric Sensitivity ................................................................ 60

vii

LIST OF FIGURES

FIGURE 1: Gas Flow Paths ................................................................................................. 4
FIGURE 2: Orifice-Volume Model Schematic ................................................................... 5
FIGURE 3: Flow Path Schematic for a Floating Ring ...................................................... 17
FIGURE 4: Force Balance Conditions for Ring Collapse ................................................. 19
FIGURE 5: Ford 5.4 L V8 Engine Blowby Map - Measured [6] ...................................... 23
FIGURE 6: Ford 5.4 L V8 Engine Blowby Map - Predicted [6] ....................................... 23
FIGURE 7: Process Flow Chart ......................................................................................... 25
FIGURE 8: Piston Ring Cross Section .............................................................................. 25
FIGURE 9: Piston Ring Top View .................................................................................... 26
FIGURE 10: Piston Ring Face Profiles ............................................................................. 26
FIGURE 11: Three Piece Oil Ring Dimensions ................................................................ 26
FIGURE 12: Piston Groove Cross Section ........................................................................ 27
FIGURE 13: Skirt Dimensions .......................................................................................... 27
FIGURE 14: Typical Blowby Map .................................................................................... 50
FIGURE 15: Ring Motion Versus Crank Angle (Ring Collapse) ..................................... 54
FIGURE 16: Aged Piston Ring and Groove with Large Clearance .................................. 57
FIGURE 17: Ring Collapse Interference ........................................................................... 57
FIGURE 18: Ring Motion Versus Crank Angle (Ring Collapse) With Top Ring Dip ..... 59
FIGURE 19: Ford 2.3 L14 Engine Blowby Map - Original Design ................................. 65
FIGURE 20: Ford 2.3 L14 Engine Blowby Map - 0.4 End Gap Ring 1 ........................... 65
FIGURE 21: Ford 2.3 L 14 Engine Blowby Map - 0.5 End Gap Ring 1 ........................... 66

viii

FIGURE 22:

FIGURE 23:

FIGURE 24:

FIGURE 25:

FIGURE 26:

FIGURE 27:

FIGURE 28:

FIGURE 29:

FIGURE 30:

FIGURE 31:

FIGURE 32:

FIGURE 33:

FIGURE 34:

FIGURE 35:

FIGURE 36:

FIGURE 37:

FIGURE 38:

FIGURE 39:

FIGURE 40:

FIGURE41:

FIGURE 42:

FIGURE 43:

FIGURE 44:

Ford 2.3 L14 Engine Blowby Map - 0.6 End Gap Ring 1 ........................... 66

Ford 2.3 L14 Engine Blowby Map - 0.7 End Gap Ring 1 ........................... 67
Ford 2.3 L14 Engine Blowby Map - 0.8 End Gap Ring 1 ........................... 67
Ford 2.3 L14 Engine Blowby Map - 0.9 End Gap Ring 1 ........................... 68
Ford 2.3 L 14 Engine Blowby Map - 1.47 Axial Width Ring 1 ................... 68
Ford 2.3 L14 Engine Blowby Map - 1.49 Axial Width Ring 1 ................... 69
Ford 2.3 L I4 Engine Blowby Map - 1.50 Axial Width Ring 1 ................... 69
Ford 2.3 L14 Engine Blowby Map - 1.51 Axial Width Ring 1 ................... 70
Ford 2.3 L14 Engine Blowby Map - 1.52 Axial Width Ring 1 ................... 70
Ford 2.3 L14 Engine Blowby Map - 1.49 Groove Height Ring 1 ............... 71
Ford 2.3 L14 Engine Blowby Map - 1.50 Groove Height Ring 1 ............... 71
Ford 2.3 L14 Engine Blowby Map - 1.51 Groove Height Ring 1 ............... 72
Ford 2.3 L14 Engine Blowby Map - 1.52 Groove Height Ring 1 ............... 72
Ford 2.3 L 14 Engine Blowby Map - 1.54 Groove Height Ring 1 ............... 73
Ford 2.3 L14 Engine Blowby Map - 4.0 Radial Thickness Ring 1 ............. 73
Ford 2.3 L 14 Engine Blowby Map - 4.1 Radial Thickness Ring 1 ............. 74
Ford 2.3 L14 Engine Blowby Map - 4.2 Radial Thickness Ring 1 ............. 74
Ford 2.3 L 14 Engine Blowby Map - 4.3 Radial Thickness Ring 1 ............. 75
Ford 2.3 L 14 Engine Blowby Map - 4.4 Radial Thickness Ring 1 ............. 75
Ford 2.3 L 14 Engine Blowby Map - 87.10 Groove Diameter Ring 1 ......... 76

Ford 2.3 L14 Engine Blowby Map - 87.30 Groove Diameter Ring 1 ......... 76
Ford 2.3 L14 Engine Blowby Map - 87.50 Groove Diameter Ring 1 ......... 77

Ford 2.3 L14 Engine Blowby Map - 87.70 Groove Diameter Ring 1 ......... 77

ix

FIGURE 45:

FIGURE 46:

FIGURE 47:

FIGURE 48:

FIGURE 49:

FIGURE 50:

FIGURE 51:

FIGURE 52:

FIGURE 53:

FIGURE 54:

FIGURE 55:

FIGURE 56:

FIGURE 57:

FIGURE 58:

FIGURE 59:

FIGURE 60:

FIGURE 61:

FIGURE 62:

FIGURE 63:

FIGURE 64:

FIGURE 65:

FIGURE 66:

FIGURE 67:

Ford 2.3 L 14 Engine Blowby Map - 87.90 Groove Diameter Ring 1 ......... 78

Ford 4.6 L V8 Engine Blowby Map - Original Design ................................ 79
Ford 4.6 L V8 Engine Blowby Map - 0.4 End Gap Ring 1 ......................... 79
Ford 4.6 L V8 Engine Blowby Map - 0.5 End Gap Ring 1 ......................... 80
Ford 4.6 L V8 Engine Blowby Map - 0.6 End Gap Ring 1 ......................... 80
Ford 4.6 L V8 Engine Blowby Map - 0.7 End Gap Ring 1 ......................... 81
Ford 4.6 L V8 Engine Blowby Map - 0.8 End Gap Ring 1 ......................... 81
Ford 4.6 L V8 Engine Blowby Map - 0.9 End Gap Ring 1 ......................... 82
Ford 4.6 L V8 Engine Blowby Map - 1.0 End Gap Ring 1 ......................... 82
Ford 4.6 L V8 Engine Blowby Map - 1.1 End Gap Ring 1 ......................... 83
Ford 4.6 L V8 Engine Blowby Map - 1.2 End Gap Ring 1 ......................... 83
Ford 4.6 L V8 Engine Blowby Map - 1.3 End Gap Ring 1 ......................... 84
Ford 4.6 L V8 Engine Blowby Map - 1.48 Axial Width Ring 1 .................. 84
Ford 4.6 L V8 Engine Blowby Map - 1.49 Axial Width Ring 1 .................. 85
Ford 4.6 L V8 Engine Blowby Map - 1.50 Axial Width Ring 1 .................. 85
Ford 4.6 L V8 Engine Blowby Map - 1.51 Axial Width Ring 1 .................. 86
Ford 4.6 L V8 Engine Blowby Map - 1.52 Axial Width Ring 1 .................. 86
Ford 4.6 L V8 Engine Blowby Map - 1.48 Groove Height Ring 1 .............. 87
Ford 4.6 L V8 Engine Blowby Map - 1.49 Groove Height Ring 1 .............. 87
Ford 4.6 L V8 Engine Blowby Map - 1.50 Groove Height Ring 1 .............. 88
Ford 4.6 L V8 Engine Blowby Map - 1.51 Groove Height Ring 1 .............. 88
Ford 4.6 L V8 Engine Blowby Map - 1.52 Groove Height Ring 1 .............. 89
Ford 4.6 L V8 Engine Blowby Map - 4.1 Radial Thickness Ring 1 ............ 89

FIGURE 68:

FIGURE 69:

FIGURE 70:

FIGURE 71:

FIGURE 72:

FIGURE 73:

FIGURE 74:

FIGURE 75:

FIGURE 76:

FIGURE 77:

FIGURE 78:

FIGURE 79:

FIGURE 80:

FIGURE 81:

FIGURE 82:

FIGURE 83:

FIGURE 84:

FIGURE 85:

FIGURE 86:

FIGURE 87:

FIGURE 88:

FIGURE 89:

FIGURE 90:

Ford 4.6 L V8 Engine Blowby Map - 4.3 Radial Thickness Ring 1 ............ 90
Ford 4.6 L V8 Engine Blowby Map - 4.5 Radial Thickness Ring 1 ............ 90
Ford 4.6 L V8 Engine Blowby Map - 4.7 Radial Thickness Ring 1 ............ 91
Ford 4.6 L V8 Engine Blowby Map - 80.91 Groove Diameter Ring 1 ........ 91

Ford 4.6 L V8 Engine Blowby Map - 81.11 Groove Diameter Ring 1 ........ 92
Ford 4.6 L V8 Engine Blowby Map - 81.31 Groove Diameter Ring 1 ........ 92
Ford 4.6 L V8 Engine Blowby Map - 81.51 Groove Diameter Ring 1 ........ 93
Ford 4.6 L V8 Engine Blowby Map - 81.71 Groove Diameter Ring 1 ........ 93

Ford 4.6 L V8 Engine Blowby Map - 81.91 Groove Diameter Ring 1 ........ 94

Ford 4.6 L V8 Engine Blowby Map - 82.11 Groove Diameter Ring 1 ........ 94
Ford 4.6 L V8 Engine Blowby Map - 82.20 Groove Diameter Ring 1 ........ 95
Ford 5.4 L V8 Engine Blowby Map - Original Design ................................ 96
Ford 5.4 L V8 Engine Blowby Map - 0.3 End Gap Ring 1 ......................... 96
Ford 5.4 L V8 Engine Blowby Map - 0.4 End Gap Ring 1 ......................... 97
Ford 5.4 L V8 Engine Blowby Map - 0.5 End Gap Ring 1 ......................... 97
Ford 5.4 L V8 Engine Blowby Map - 0.6 End Gap Ring 1 ......................... 98
Ford 5.4 L V8 Engine Blowby Map - 0.7 End Gap Ring 1 ......................... 98
Ford 5.4 L V8 Engine Blowby Map - 0.8 End Gap Ring 1 ......................... 99
Ford 5.4 L V8 Engine Blowby Map - 0.9 End Gap Ring 1 ......................... 99
Ford 5.4 L V8 Engine Blowby Map - 1.46 Axial Width Ring 1 ................ 100
Ford 5.4 L V8 Engine Blowby Map - 1.47 Axial Width Ring 1 ................ 100
Ford 5.4 L V8 Engine Blowby Map - 1.48 Axial Width Ring 1 ................ 101
Ford 5.4 L V8 Engine Blowby Map - 1.49 Axial Width Ring 1 ................ 101

xi

FIGURE 91: Ford 5.4 L V8 Engine Blowby Map - 1.50 Axial Width Ring 1 ................ 102

FIGURE 92: Ford 5.4 L V8 Engine Blowby Map - 1.51 Axial Width Ring 1 ................ 102
FIGURE 93: Ford 5.4 L V8 Engine Blowby Map - 1.52 Axial Width Ring 1 ................ 103
FIGURE 94: Ford 5.4 L V8 Engine Blowby Map - 1.46 Groove Height Ring 1 ............ 103
FIGURE 95: Ford 5.4 L V8 Engine Blowby Map - 1.47 Groove Height Ring 1 ............ 104
FIGURE 96: Ford 5.4 L V8 Engine Blowby Map - 1.48 Groove Height Ring 1 ............ 104
FIGURE 97: Ford 5.4 L V8 Engine Blowby Map - 1.49 Groove Height Ring 1 ............ 105
FIGURE 98: Ford 5.4 L V8 Engine Blowby Map - 1.50 Groove Height Ring 1 ............ 105
FIGURE 99: Ford 5.4 L V8 Engine Blowby Map - 1.51 Groove Height Ring 1 ............ 106
FIGURE 100: Ford 5.4 L V8 Engine Blowby Map - 1.52 Groove Height Ring 1 .......... 106
FIGURE 101: Ford 5.4 L V8 Engine Blowby Map - 1.54 Groove Height Ring 1 .......... 107
FIGURE 102: Ford 5.4 L V8 Engine Blowby Map - 1.55 Groove Height Ring 1 .......... 107
FIGURE 103: Ford 5.4 L V8 Engine Blowby Map - 3.2 Radial Thickness Ring 1 ........ 108
FIGURE 104: Ford 5.4 L V8 Engine Blowby Map - 3.3 Radial Thickness Ring 1 ........ 108
FIGURE 105: Ford 5.4 L V8 Engine Blowby Map - 3.4 Radial Thickness Ring 1 ........ 109
FIGURE 106: Ford 5.4 L V8 Engine Blowby Map - 3.5 Radial Thickness Ring 1 ........ 109
FIGURE 107: Ford 5.4 L V8 Engine Blowby Map - 3.6 Radial Thickness Ring 1 ........ 110
FIGURE 108: Ford 5.4 L V8 Engine Blowby Map - 3.7 Radial Thickness Ring 1 ........ 110
FIGURE 109: Ford 5.4 L V8 Engine Blowby Map - 3.8 Radial Thickness Ring 1 ........ 111
FIGURE 110: Ford 5.4 L V8 Engine Blowby Map - 3.9 Radial Thickness Ring 1 ........ 111
FIGURE 111: Ford 5.4 L V8 Engine Blowby Map — 4.0 Radial Thickness Ring 1 ........ 112
FIGURE 112: Ford 5.4 L V8 Engine Blowby Map - 82.00 Groove Diameter Ring 1....112
FIGURE 113: Ford 5.4 L V8 Engine Blowby Map - 82.40 Groove Diameter Ring 1....113

xii

FIGURE 114:

FIGURE 115:

FIGURE 116:

FIGURE 117:

FIGURE 118:

FIGURE 119:

FIGURE 120:

FIGURE 121:

FIGURE 122:

FIGURE 123:

FIGURE 124:

FIGURE 125:

FIGURE 126:

Ford 5.4 L V8 Engine Blowby Map - 82.60 Groove Diameter Ring 1....
Ford 5.4 L V8 Engine Blowby Map - 82.60 Groove Diameter Ring 1....
Ford 5.4 L V8 Engine Blowby Map - 82.80 Groove Diameter Ring 1....
Ford 5.4 L V8 Engine Blowby Map - 83.00 Groove Diameter Ring 1....
Ford 5.4 L V8 Engine Blowby Map - 83.20 Groove Diameter Ring 1....
Ford 5.4 L V8 Engine Blowby Map - 0.3 End Gap Ring 1 & 2 ............
Ford 5.4 L V8 Engine Blowby Map - 0.4 End Gap Ring 1 & 2 ............
Ford 5.4 L V8 Engine Blowby Map - 0.4 End Gap Ring 1 & 2 ............
Ford 5.4 L V8 Engine Blowby Map - 0.5 End Gap Ring 1 & 2 ............
Ford 5.4 L V8 Engine Blowby Map - 0.6 End Gap Ring 1 & 2 ............
Ford 5.4 L V8 Engine Blowby Map - 0.7 End Gap Ring 1 & 2 ............
Ford 5.4 L V8 Engine Blowby Map - 0.8 End Gap Ring 1 & 2 ............

Ford 5.4 L V8 Engine Blowby Map - 0.9 End Gap Ring 1 & 2 ............

xiii

113

114

114

115

115

..116

..116

..117

..117

..118

..118

..119

..119

NOMENCLATURE

English Symbols
Name Definition
0 Axial acceleration of the ring

Abore

max
AN

A

pouterface

A

pinnerface

A

ring

Area pressure force acts on

Maximum bore area

Maximum flow area

Flow area for ring N

Area of outer ring face

Area of inner ring face

Area occupied by the ring

Specific heat at constant volume

Inner surface diameter on which pressure force acts
Bore diameter

Effective ring outer diameter

Modulus of elasticity

Friction force

xiv

Units

Pa

II?!
FP

F

tension

FT

P

groove

PN

Inertial force

Pressure force

Ring tension force

Ring tension force

Moment of Inertia

Orifice discharge coefficient

Blowby parameter

Mass

Mass flow rate

Non—dimensionalized mass flow rate for ring N

Pressure behind ring

Effective ring perimeter

Pressure

Non-dimensionalized pressure

Atmospheric pressure

Critical pressure

Pressure behind ring groove

Pressure above ring N

XV

4
m

unitless

K1 /2
Pa — radians

unitless

Pa

Pa

unitless

Pa
Pa
Pa

Pa

VN

xendgap

Greek Symbols

Name

8

f

Gas constant for air

Distance of flow
Time
Axial width of ring

Temperature

Non-dimensionalized temperature

Combustion chamber temperature
Temperature above ring N

Internal energy of gas at ring N

Axial velocity of ring

Critical flow velocity

Velocity of the gas flowing past ring N

Volume below ring N

End gap clearance

Definition

radial displacement

Specific heat ratio

xvi

SCC

Units

unitless

PN

0

Kinematic coefficient friction

Angular crankshaft velocity

Pi

Density of flow at ring N

Crank angle position

Acronyms and Abbreviations

Name

CASE

ENGSIM

GESIM

HC

WOT

Definition

Cylinder kit Analysis System for Engines
Engine Simulation

General Engine Simulation

Hydrocarbon

Wide Open Throttle

xvii

unitless

radians
sec

 

unitless

kg

3
m

radians

CHAPTER 1. INTRODUCTION

1.1 Overview
The primary function of piston rings is to provide a moveable seal in a cylinder

kit to prevent combustion gases from moving past the piston. Blowby is defined in this
thesis as the sum of the gases that flows past the top piston ring either towards the
crankcase (foreflow) or back into the combustion chamber (backflow). Foreflow
“...decreases horsepower, decreased engine torque, increases oil contamination, [and]
decreases engine life...” [1] Backflow increases hydrocarbon emissions and increases oil
consumption. More specifically, “... piston ring pack crevices [are] responsible for 80% of
the total HC returning from the crevices to the cylinder after combustion. [2] In order for
an engine to perform desirably, piston rings must be designed specially to function with a
particular cylinder kit.

One of the great challenges automotive engineers face in cylinder kit design
today is the large number of Operating conditions for which the designs must perform. In
the past, testing a design for 10 loads and 10 engine speeds would require 100
measurements with consistent setups. Often measurements or computer predictions in
previous studies would be made fixed at full or minimal load conditions for a few engine
speeds [3]. However, as Shown later in this thesis, cylinder kit performance can vary a
great deal depending upon the operating conditions.

Due to recent computer advancements, software has been developed at
Michigan State University to predict cylinder kit performance for over 100 operating

conditions within minutes. This program, the Cylinder kit Analysis System for Engines

(CASE), has made it possible to perform a parametric study for a large set Of Operating
conditions.

A blowby optimization (minimization) program was originally developed to
try to find the optimal piston ring axial thickness, and piston ring end gap. After running
the optimization for four different engines at several operating conditions, it was found
that both the axial thickness, and the end gap Often ended up at the design constraints. The
parameter predictions that did not lie at the constraints Showed an insignificant influence
on the blowby performance. Such an Observation would suggest that perhaps there existed

a “proportional” relationship between blowby and certain cylinder kit design parameters.

1.2 Motivation
Discovering the direct relationships between blowby and various ring

geometric parameters would significantly reduce both initial design and redesign times.
Understanding the behavior of blowby performance as simple cause and effect
relationships is currently more time efficient than producing a sophisticated cylinder kit
Optimization program.
1.2.1 Advantages Over Optimization Program

There are several complications in producing a useful optimization program.
The coupled equations approximating ring behavior are difficult and too computationally
intensive to solve semi-analytically for more than a couple of design variables
simultaneously. Purely numerical methods utilizing ring pack modeling programs as a
black box to obtain blowby values, require that the black box be executed several
thousands of times due to the scores of operating points in which an engine runs. Even

with some of the fastest operating black boxes taking approximately three seconds per run,

several days Of Optimization may be required to find a local Optimum point—not even a
global optimum point. To find the global optimum point, several optimizations would have
to be run at different initial design parameter guesses. In other words, computing
technology and creative Optimization techniques will require significant development
before optimization programs will be worthwhile in determining ideal cylinder kit

geometries.

1.2.2 Advantages Over Physical Testing
Besides saving on cost and time (by not producing custom piston rings), using

a numerical simulation for the study had other beneficial aspects over physical testing.
“Generally only the gas flowing into the crankcase can be measured.” [4] Accounting for
the blowby flowing (backflow) into the combustion chamber is important since it strongly
affects hydrocarbon emissions. Furthermore, problems associated with running an engine

at high RPMS and WOT for long periods of time are avoided.

1.3 Objectives
The Objective of the study in the thesis was to determine the influences on

blowby due to the following design parameters: end gap clearance, axial width, groove
height, radial thickness, and groove diameter. Ford 5.4 L, 4.6 L, and 2.3 L four-stroke
gasoline engines were simulated in the study. Engine loads ranged from idling (0%) to
maximum engine load (100%) in ~8.333% increments, and from 1000 to 5000 RPM in
500 RPM increments. Further details of the experiment step is documented in

Heading 5.1.

CHAPTER 2. FUNDAMENTAL GAS DYNAMICS THEORY
2.1 Introduction to Gas Flows in Cylinder Kits

Combustion gases flow through piston ring packs due to differences in
pressures above and below piston rings. The gases usually flow through the end gaps, the
clearance between the ring top and its respective groove top, and the clearance between

the ring bottom and its respective groove bottom.

R Combustion Chamber
Piston ing /

Top (,‘ompression Ring
/ Cylinder Wall

/ First Piston Land

 

 

 

 

 

  
 

 

nd Gap Clearance

/ Second Compression Ring
Piston

 

 

 

 

 

 

Figure 1: Gas Flow Paths

Engine designers must consider several issues. End gap areas gradually
increase due to ring wear. [5] Sometimes a consquence of increased end gap clearances,
there is a phenomenon called piston ring collapse in which large amounts of combustion
gases can flow across the piston ring face. [6] Gases can also travel across the ring face in
the case of severe bore distortion. Under such circumstances, almost all of the oil is
removed from the liner at the points of contact, causing rapid wear and possibly seizure.
These above are examples of some problems, that need to be addressed when designing an

cylinder kit. Many of these problems can be solved with well-designed models.

Gas Flow Model
The orifice-volume model is used in the Cylinder kit Analysis System for

2.2

Engines (CASE) to determine the gas flow through the end gaps and the radial clearance
between the piston groove and the piston ring. These “orifices” are assumed to be
square-edged. AS shown in Figure 2, the volumes are the spaces enclosed by the rings
adjacent to the piston lands, and the space formed by the internal grooves and the

respective inner surface piston rings surfaces.

 

 

 

 

 

 

PNv TN
N Rin
ANAN 8 N / g
. airs—um infra—6‘7? .
I O I
I v. f. I
I PN+I~ TN+L N 5 Control I N+1 Ring
I AN+I~ “MI .1: Volume z/
I—
I iri—i—a-irq W
3- N+1
, a.
PN+2~ TN+2: "(N+1

 

 

 

 

 

 

Figure 2: Orifice-Volume Model Schematic

In the orifice-volume model used, gas flow calculations are one-dimensional.
As the gas flows through the ring pack, it assumes the temperature of the adjacent piston
land. The temperature of the piston lands are assumed to be constant with respect to time.
The gas flow through the ring pack is highly dependent on the gas discharge coefficient.
Yun, Chun, and Lee [7] found that discharge coefficients of 0.83 overestimate the
inter-ring gas pressures. According to Heywood [8] and previous tests with Ford and
Daimler Chrysler, analyses (with the CASE system) indicated that 0.65 was an appropriate

selection for the discharge coefficient for a gasoline engine.

The calculations of the inter-ring gas pressures are found using an iterative
process. Initially, a guess of the inter-ring gas pressure is made. The mass flow rates are
calculated using this guess. Utilizing these mass flow rates, a new set of inter-ring gas
pressures are calculated and compared to the original guess. If the guess does not match
the new set of inter—ring gas pressures, the process is repeated using the new pressures as
the guess.

Although the CASE system supports piston tilt analysis, piston tilt was omitted
from the study for simplicity and time savings. According to Truscott, Reid and
Ruddy [9], the piston tilt’s effect on gas flows is negligible in both measured and

simulated studies.

2.3 Energy Balance
The following energy analysis will consider a steady gas flow through a control

volume, as shown in Figure 2. All gases entering from 1 must exit through 2, due to the
steady flow assumption. Since the heat transfer rate is very small, the flow is considered to
be adiabatic. The Reynolds number in inter-ring gas flows are sufficiently high, such that

viscous effects can be neglected; the flow is isentropic. The work done in the control

volume by the gas is assumed to be negligible. [5] However, there is assumed to be flow

work at the inlet and exit of the control volume. They are given as follows:

Inlet Flow Work

Exit Flow Work

Force x Distance
Mass

PNANXSN

m

 

1 (1)
PA x—
N N ANpN
PN
PN

Force x Distance
Mass

 

PN+1AN+IXSN+I

 

1 (2)

AN+1PN+1

 

where P is pressure, A is flow area, S is distance, m is mass and p is gas

density. The subscript N represents the control volume inlet, while the subscript N + 1

represents the control volume exit.

Since the control volume is relatively small, gravitational potential energy

effects are negligible. The internal energies and velocities at the inlet and exit of the

control volume are significant and are thus included in the final energy balance equation.

The final energy balance energy equation per unit mass is given as

IiI_PN+l

 

PN pN+I

= “N+1—“NI"

2 2
VN+1“’N

2 (3)

where u is the internal energy of the gas and v is the velocity of the gas.

2.4

Thermodynamic Gas Model
The high temperatures present in combustion gases allows the ideal gas law

equation of state to be used with relatively insignificant error. This equation of state is

P = pRT (4)

where P is the absolute pressure, p is the gas density, R is the gas constant for

air and T is the temperature on an absolute scale.

From the assumption that the flow is isentropic, and the ideal gas relations, it

can be shown then that

2.5

P~ = (pi/+1)? =( TN )iY—l (5)

PN+I PN TN+I

 

 

 

where y is the specific heat ratio.

Mass Flow Model
The one-dimensional continuity equation is

- dm
pNANvN = pN+1AN+lvN+l = m = E (6)

where m is mass flow rate, m is mass and t is time.

Knowing that the u N + I — u N in Equation (3) can be replaced by

“N+I‘“N = Cv(TN+I"TN) (7)

where cv is the specific heat at constant volume, Equation (3) can be solved for

velocity of the orifice flow. If vN is set to zero, the relative exiting velocity (vN + l ) can be

given by

 

 

vN+1 = J2((f’_"_PN+‘)+cv(TN—TN+,)) (8)

ON pN+l

cv in Equation (8) can be replaced knowing

L

 

c. = y_ 1 (9)
thus giving
2 P P
v~+n=JH.)(—~-—~+—')
Y pN pN+ I

By using the isentropic relations given in Equation (5), terms in Equation (10)

can be replaced as shown in Equation (11) and Equation (12).
( -|)
(P__N_PN+1)=P__N1_(PN+I)YY (11)
PN PN+1 PN PN

= j(;j—,);’—;[l—("—g;—I)#] (12)

Using Equation (4), Equation (5), Equation (6), and Equation (12), the

 

 

following mass flow rate equation can be developed:

 

3 L11
".1 _ A ZYPNPN (PN+1)7_(PN+1) 7
" N+1 'Y-l PN PN

 

 

(13)

Equation (13) clearly shows that if mass flow rate is plotted against the

PN+
PN

 

pressure ratio I that mass flow rate is parabolic. However, due to a choked flow

phenomenon, Equation (13) applies only for a pressure ratio greater than the critical

pressure ratio. This critical pressure ratio is found by differentiating Equation (13) with

 

 

respect to PN + I , setting dpm equal to zero and solving for PN+ I . Performing these
N + l
operations yields
I
PN 1 = P = “(LY-j (14)
+ din _ 0 c 7+ 1
dPN+I -

where PC is the critical pressure.

Since for combustion gases 7 is approximately 1.3, that would mean that the

critical pressure ratio is

PC
107 _ 0.546 (15)

The fluid velocity for pressure ratios below the critical pressure ratio can be

found by inserting the critical pressure into Equation (12). Thus, the choked flow velocity

(vc)is

 

vc=J(%)’;—t[l-(9;)‘l¥‘”]

where p c is the density at critical pressure.

10

Using Equation (5) and Equation (14), Equation ( 16) can be simplified to

/ PC (17)
v = —
C pc

Equation (17) shows that the choked flow velocity is equal to that of the
velocity of sound. Therefore, the calculations are shown to be consistent to the Mach
number characteristic of choked flows. [10]

However, the theoretical mass flow rate calculated above is greater than that of
the actual flow. This difference is attributed to frictional losses and streamline
convergence. The coefficient of velocity and coefficient of convergence correct the
theoretical model for the two respective losses. These two coefficients are multiplied
together to form the orifice discharge coefficient. As mentioned earlier, for gasoline

engines the orifice discharge coefficient is 0.65. 80
Manual = Kc’htheorelical (18)

where K c is the orifice discharge coefficient.

While now it has been shown that mass flow varies with pressure, pressure also
varies with mass flow rate. Consider the ideal gas equation of state written in terms of

mass instead of volume—refer to Figure 2 for subscript definitions.

_ RTN+1

N+1 — TN—mN (19)

Solving Equation (19) for a time, At, after the initial time, t, the change in
pressure can be defined as

P +AP -RT”*' ’A ' A 20
N+1 N+1-T(mN+mN t-n1N+1 t) ( )

ll

Letting At approach zero, Equation (20) becomes

 

dPN+ l RTN+ l . -
dt - T(mN—mN+ 1) (21)
2.6 Numerical Procedure

Calculating mass flow rates using a numerical procedure first requires that the
variables in the equations used are non—dimensionalized. Omitting this
non-dimensionalization step often leads to having numerical stability problems.

Inter-ring gas pressure is non-dimensionalized by

P

atm

P*=

 

P (22)

where P is the atmospheric pressure.

arm
Temperature is non-dimensionalized by

t

T = (23)

T
TC
where Tc is the combustion chamber temperature.

Mass can be non-dimensionalized using

m* = ——'—7-l—— (24)

(VI Patm)
RTC

where VI is the volume between the first and second compression rings.

 

In order to make Equation (13) more applicable to engine studies, time (t) is

replaced using

(25)

ll
SICD

12

where 9 is the crank angle, and a) is the engine speed in radians per second.

 

y—l
* * * l/ at: _
d6 VIaMlW- 1) A1 ’7; PN PN

Since the first two fractions on the left-side of Equation (26) are constant with

 

 

respect to crank angle, they can be factored out. These fractions combined are called the

blowby parameter, K I.

K- = KcAl ZYRTC (27)
' Vlw’lW-l)

Thus, Equation (26) can be rewritten in shorter form as

 

 

 

7—1
It all Ill l/Y * -—
dm A P P P Y
#19173) "...":‘[] [———] <28>
1 E PN PN

For backfiow (flow towards the combustion chamber), the mass flow equation

can be given as

 

y—l
* r * i/y .. —
dm A P P P Y
‘2?” = ‘Ki(/TN) {—le [ *N] 1_[_*_N_] (29)
l TN+1 PN+1 PN+1

The choked flow phenomenon described in Heading 2.5 must be taken into

 

consideration for Equation (28) and Equation (29). For foreflow (flow towards the

13

crankcase) Equation (30) describes the maximum flow rate that can occur regardless of

pressure ratio.

 

 

dmrv] A N P;
_ = 0.227K,.(—) (30)
[ d6 choked A] m

:3

The maximum backflow that can occur is given by
A P
= —0.227K,.(—") N *‘

[dmfv]
d6 A f *-
] TN+ l

The rate at which pressure changes due to mass flow should also be

 

 

choked

non-dimensionalized to avoid numerical stability problems. Non-dimensionalizing

Equation (21) yields
(iii; * ‘/l .* .*
76' : T~+1(V-)(mN-"1N+1) (31)
N

14

CHAPTER 3. RING DYNAMICS THEORY

3.1 Introduction to Ring Dynamics
The forces that act on piston rings can be divided into the following two

catagories: axial forces and radial forces. The axial position of the piston ring at different
stages of the engine cycle are determined by axial forces. Radial forces determine whether

or not a piston ring collapses inward.

3.2 Ring Forces in Axial Direction
There are three primary forces that influence piston ring dynamics. The two

other lesser forces, lubricant squeeze force and lubricant adhesive force, are relatively
insignificant. The three primary forces include inertia, pressure, and friction. The relative
effects of the these forces on piston rings are highly dependent on the operating
conditions. At high engine speeds and low engine loads, inertial forces become more
dominant than the pressure forces. The opposite is also true; pressure forces are more
dominant than inertial forces at lower engine speeds and high engine loads. Frictional

forces even at low engine speeds and low loads, do not influence ring motion very much.

3.2.1 Inertial Force

The inertial force, F ,, can be given simply as

F , = —ma (32)

where m is the mass of the ring and a is the axial acceleration of the ring. If
the ring is in contact with the piston groove, the ring’s axial acceleration is the same as the

piston. Pressure and friction forces determine the ring’s acceleration if the ring is floating

in the piston groove.

15

3.2.2 Pressure Forces

The pressure forces, F P, acting on the bottom and top of the piston rings can
be modeled with

F P = P(r)A (33)

where P(r) is the pressure magnitude as a function of varying with radius, and
A is the ring’s surface area in which the pressure acts. It was assumed that the pressure
dropped linearly from the outer to inner ring surface. The details of the pressure
calculations are shown in Equation (31).

The area affected by the pressure is

A = 112(D2—d2) (34)

where D is the bore diameter, and d varies depending upon the position of the
ring. If the ring is seated at the bottom of its groove, d is the bore diameter minus two

times the ring width. If the ring is touching the t0p of its groove, d is the piston land

diameter.

3.2.3 Friction Forces

The friction forces, F F, between the piston’s ring face and cylinder liner can

be approximated by the semi-empirical equation

FF .-. (p(nD:a,)+FT)(4.8 ’2“) (35)

where p is the pressure behind the ring, tax is the axial width of the ring, F T is

 

the force due to ring tension, )1 is the kinematic coefficient of friction, and var is the

ring’s axial velocity. [5]

l6

3.3 Ring Flutter
Although the relative magnitude of the friction force is much less than either

the pressure forces and inertial forces, it becomes an important factor when the pressure
and inertial forces are nearly equal. When pressure and inertial forces on a piston ring are
close in magnitude, the piston ring will have a tendency to quickly oscillate axially in its
groove.

This “fluttering” motion occurs because the pressure and inertial forces
continually alternate dominance as the gas flow paths change due to the ring motion. In
the instance in which ring flutter occurs near the end of the compression stroke, inertial
and pressure forces move the ring to the top of its groove. As the ring moves to the top of
its groove, it is floating and thus a flow path is opened between the ring bottom and the

groove bottom. As the ring reaches the top of its groove, the increasing pressure forces at

 

 

 

 

 

 

 

 

 

 

 

Figure 3: Flow Path Schematic for a Floating Ring

the end of the compression stroke push the ring back down. Before the ring is properly
seated at the bottom of its groove. Gases can pass behind the floating ring’s groove
equalizing the pressure above and below the ring. The inertial force then causes the ring to
return to the top of the groove. This motion can then repeat itself, impairing the ring’s

sealing objective.

l7

While engine designers strive to reduce friction as much as possible, friction
actually acts beneficially during the presence of conditions favorable to ring flutter. Since
friction forces oppose any ring motion, they dampen these ring flutter oscillations and help
to inhibit conditions that would initiate the phenomenon. Although friction causes piston
ring and cylinder liner wear, its very limited presence improves ring stability.

In some instances, ring flutter can be a contributing factor to another unwanted
ring behavior called ring collapse. Ring flutter also is sometimes the result of ring collapse
and is an indication that ring collapse is likely to be present. Ring collapse is explained in
detail in Heading 3.4.

3.4 Ring Collapse

Ring collapse is an undesirable phenomenon in which the piston ring moves
radially. That is, the ring face separates from the cylinder wall creating a large area in
which combustion gases can easily flow past. Ring collapse is much more detrimental to
blowby performance than ring flutter.

This condition occurs when the forces acting on the ring face exceed the
combined forces of the ring tension and the gas pressure behind the ring. Conditions
favorable for ring collapse usually coincide with high engine speeds and low engine load.
These operating conditions cause a piston ring to seat at the top of its piston groove near
the end of a compression stroke; the high inertial forces (due to the high engine speed)
combined with the relatively low pressure forces (due to the load engine load) keep the
ring from seating on the bottom of its groove. It is undesirable to have the piston ring
seated at the top of its groove since, that means the pressure gases below the ring (which

are lower in magnitude than the pressure of the gases above the ring) are supporting the

18

ring radially. Thus, the pressure force applied to the ring face, could overcome the ring
tension and gas pressure exerted from behind the ring. A force balance diagram for a

scenario favoring ring collapse is shown in Figure 4.

 

Press. High
Inertial Force I
I

Press. High

 

    

. . "__]

Press. Lowest T’ l " "
....

Ring Tension j‘j
I I I 4,, . Press. LOW
....LLLIWL

______-_.,_t--auL.5L.~ . ‘

-._

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Press. Low
Figure 4: Force Balance Conditions for Ring Collapse

 

 

 

In Figure 4 ring tension is shown to be the smallest force in the force diagram.
Ring tension is on the order of 25 Newtons of force for automotive gasoline engines.
Whereas, the pressure force behind the top compression ring (Press. Lowest in Figure 4)
can be around 200 Newtons for a standard gasoline engine under ring collapse
conditions—even higher for diesel engines. Thus, adjusting ring tension to avoid ring
collapse is unreasonable. [5] Ring tension is only useful for initially setting piston rings in
a position where combustion gases can easily create the support forces behind the ring (to
avoid ring collapse).

The equation governing whether ring collapse will occur is

(PN + PN+1)Apouterface F

2 tension

+ P (36)

groove‘ ‘pinnerface

where PN is the pressure above ring N, PN + I is the pressure below ring N,

A

is the projected ring face surface area in the radial direction, F is the

pouterface tension

19

force due to ring tension, P is the pressure in the groove behind the piston ring, and

groove

A is the projected inner ring surface area in the radial direction.

pinnerface
When a piston ring collapses, a large area is opened up between the ring face
and the cylinder liner. In order to find this area, the radial displacement of the piston ring

must be defined. The radial displacement at any point of a ring is given by

649) = ——

PR4(
El

1 — c056 + gsin 9) (37)

where 9 is the angular location of a point on a ring, P is the net radial load due
to pressure and ring tension, R is the central radius of the ring, E is the modulus of
elasticity of the ring material, and I is the moment of inertia of the ring cross section. Zero

radians for 9 is located on the side of the ring opposite of the ring gap.

The additional gas flow path that opens up in the event of ring collapse can

then be defined as
A = 2r 5,Rd0 (38)
0
Substituting Equation (37) into Equation (38), and solving the integral yields

= 3mmS

A El

(39)

 

the area added to the ring gap area in the gas flow calculations.
Under the circumstance that the ring end gap clearance is small, it is possible
that the radial displacement may be restricted due to the ends of the ring butting. To find

the maximum flow area that can occur between the ring face and the cylinder liner,

20

consider the area occupied by the piston ring, if its end clearance is zero. Before finding

the area, the effective ring perimeter, peff must be calculated using

pt’ff = TED—xendgap (40)

where D is the bore diameter (the original diameter of the outer ring surface)

and x is the end gap clearance. An effective ring outer diameter D e f can be found

endgap

from Equation (40); it is defined as

 

x
D = D— ——"”"~‘~"’” 41

(ff n ( )
The area occupied by the ring, An."g is simply

(D m2
Aring — + (42)
The maximum flow area, Am“ , is by definition to be
Amax = Abore —Aring (43)
where
1:02

Abore = 4 (44)

So Equation (43) can be simplified in terms of end gap clearance and bore
diameter such that

l

Amax = ixendgap

D (45)

21

CHAPTER 4. COMPUTER SIMULATION VALIDATION

4.1 Overview
The CASE system has had much “real-world” testing and analysis. The

uncalibrated past results in the correlate well with measured values. This chapter will
provide a brief overview of how the CASE system results have compared to measured
results in a past study on the same Ford 5.4 L engine. The Ford 5.4 L measured engine

data was the only data set in which publishing permissions were given.

4.2 Comparisons
Figure 5 shows the measured blowby map values and Figure 6 shows the

predicted blowby map values.
4.2.1 Comparing Predicted Blowby Maps

Figure 6’s values appears to be different from the predicted values found in
Figure 79. The difference applies to the interpretation of blowby. Ejakov’s [6] definition of
blowby was the amount of air flowing from the combustion chamber past the first
compression ring. In this thesis, his definition is referred to as foreflow. This thesis defines
blowby as the combination of foreflow and backflow. Therefore, if Ejakov’s backflow
results were summed with his blowby results, the end product would be identical to those

found in Figure 79.

4.2.2 Comparing Measured and Predicted Blowby Maps
Figure 5 and Figure 6 show good overall trend correlation. The shape of the

blowby map was slightly off in the high engine speed and low engine load region.

However, the significant phenomenon of ring collapse was predicted by CASE in this

22

 

region. While the magnitude of the two plots differed slightly, their similarity was accurate

enough such that valid predictions could be made from the CASE system results.

 

2:53

3’:

 

.5
in

 

BLOW-BYfllmlnl
p
o

d
o
O

 

o
in

m ENGINE
o 2 150° SPEED (rpm)
4 5 8 1° 12 14 woo

 

 

MANIFOLD VAcuuu (In) 2° 2’
Figure 5: Ford 5.4 L V8 Engine Blowby Map - Measured [6]

 

 

 

 

BLOW-BY (l I mhlcyl)

 

 

4
6 8 10‘2““1.
macaw (In) 2’

 

 

Figure 6: Ford 5.4 L V8 Engine Blowby Map - Predicted [6]

23

CHAPTER 5. COMPUTER SIMULATION SETUP

5.1 Simulation Hardware and Software
The cylinder kit simulation was performed using a computer of the following

configuration:

Table 1: Computer Hardware

 

 

 

 

CPU Intel Pentium III - 500 MHz
Motherboard ABit BH6 - 100 MHz Bus
Memory 128 MB

Hard Disk IBM EIDE 7200 RPM - 10 GB

 

 

 

 

The software used in the study is shown in Table 2.

Table 2: Computer Software

 

Operating System Linux - Mandrake Distribution 7.0

 

Modeling Program Cylinder kit Analysis System for Engines (CASE)
CASE Modules RING, WebCASE
Web Server Roxen Challenger 1.3

 

 

 

 

 

 

To expedite the parametric study on cylinder kit performance, a web page
interface was created. The backend of the web page (CGI scripts) automatically calculated
ring mass based on material density, and geometry of the piston ring. The crevice volumes
described in Heading 2.2 were also automatically calculated using dimensions of the bore,

piston and piston ring. Most importantly, WebCASE was developed to automate the

24

simulation of all operating conditions for any given cylinder kit configuration. Figure 7

summarizes the simulation process.

 

 

Cylinder Kit Input

 

 

 

 

 

 

 

 

 

 

 

Operating Conditions Input

 

 

 

 

Ring Mass Calculation
Crevice Volume Calculations
Unit Conversions

 

 

 

___, RING Module

 

 

 

 

 

 

 

Figure 7: Process Flow Chart

5.2 Operating Conditions
The performance of ring packs varies greatly depending on operating

conditions. Automobile engines must be designed to function for a large variety of
operating conditions. Thus, the simulation was performed for 117 operating conditions for
each geometry. Engine loads ranged from idling (0%) to maximum engine load (100%) in

~8.333% increments, and from 1000 to 5000 RPM in 500 RPM increments.

5.3 Cylinder Kit Schematics

This section contains simple schematics of cylinder kit components to help

visualize dimensions and terminology described later in this thesis.

 

Radial Thickness
‘ >I Outer Ring Face

 

 

 

Axial Width

 

 

 

 

 

Inner Ring Face

 

Figure 8: Piston Ring Cross Section

25

 

 

Ring End Gap Clearance
__L
T

 

Figure 9: Piston Ring Top View

 

 

 

 

 

 

 

 

Barrel
. Effective
Center Line Ring Face
_/ Barrel Face Height
Radius of Offset
Curvature
Composite
‘ X1
Effective
X4 Ring Fac
_ Height
7 ‘7 x3

 

Parabolic

 

 

 

 

 

 

 

, Effective
Center Line Ring Fac
Parabolic Face Height
Offset
Crown Height l"
Taper
<\
Slope of
Ring Face Effective
Ring Fac
Height

 

 

 

Figure 10: Piston Ring Face Profiles

 

 

 

 

 

 

 

Oi] Ring Dimension 1

 

 

(Top Segment )
Expander
(Bottom Segment ) jj
, , , , ’j Oil Ring Dimension 2
01] Ring D1mensron 3

 

Figure 11: Three Piece Oil Ring Dimensions

26

 

 

 

Groove Width

4—4
l
l

 

 

 

 

 

 

 

 

 

 

 

 

Groove Diameter (to center of piston) Groove Height
’
Figure 12: Piston Groove Cross Section

I l
I l

I J
T l

l j

 

 

 

, , SHTB
Skirt Height i

 

 

 

Skirt Width

 

 

 

Figure 13: Skirt Dimensions

5.4 Engines Simulated
Three different Ford Motor Company engines were used in the parametric

study performed for this thesis. These engines were a 5.4 L V8 engine, a 4.6 L V8 engine,
and a 2.3 L 14 engine. All of these engines had similar original ring pack designs; the bore
diameters of the engines were similar. The 5 .4 L engine has the longest stroke, while the
2.3 L engine has the shortest stroke of the three engines. The exact cylinder kit

specifications are as shown in Table 3, Table 4, and Table 5.

27

Table 3: Ford 5.4 L V8 2 Valve Cylinder Kit Specifications
Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring

Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring # Value Units
Number of Compression Rings 2
Number of Oil Rings 1
Piston Groove Height 1 1.53 mm
Piston Groove Width 1 3.5 mm
Piston Groove Diameter 1 82.2 mm
Ring Face Profile Type 1 parabolic
Effective Ring Face Height 1 1.2 mm
Crown Height of Ring Face 1 0.009 mm
Ring Tension 1 23.8 N
Ring Mass 1 000965479 kg
Ring Modulus of Elasticity l 9.6781E+10 Pa
Ring Poisson’s Ratio 1 0.31
Ring Mass Density 1 7196.8 kg/m3
Ring Conduction Coefficient 1 63.0 W/(m*K)
Ring Coefficient of Thermal Expansion 1 6.55E-06 1/K
Axial Width (Ring Thickness) l 1.45 mm
Radial Thickness (Ring Width) 1 3.4 mm
Ring Surface Roughness 1 0.000127 mm
Piston Groove Height 2 1.54 mm
Piston Groove Width 2 4.5 mm
Piston Groove Diameter 2 80.2 mm
Ring Face Profile Type 2 taper
Effective Ring Face Height 2 1.45 mm
Ring Slope of Taper Face 2 2.0 deg
Ring Tension 2 28.9 N

 

28

 

Table 3: Ford 5.4 L V8 2 Valve Cylinder Kit Specifications
Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring

Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring # Value Units
Ring Mass 2 0.0110108 kg
Ring Modulus of Elasticity 2 8.9431E+10 Pa
Ring Poisson’s Ratio 2 0.31
Ring Mass Density 2 7196.8 kg/m3
Ring Conduction Coefficient 2 63.0 W/(m*K)
Ring Coefficient of Thermal Expansion 2 6.55E-06 l/K
Ring Axial Width (Ring Thickness) 2 1.45 mm
Radial Thickness (Ring Width) 2 3.9 mm
Ring Surface Roughness 2 0.000127 mm
Piston Groove Height 4, 5 3.035 mm
Piston Groove Width 4, 5 4.15 mm
Piston Groove Diameter 4, 5 80.9 mm
Oil Ring Type 4, 5 Three-Piece
Oil Control Ring Dimension 1 4, 5 3.015 mm
Oil Control Ring Dimension 2 4, 5 2.73 mm
Oil Control Ring Dimension 3 4, 5 0.478 mm
Ring Face Profile Type 4 barrel
Effective Ring Face Height 4 0.478 mm
Radius of Curvature of Barrel Face 4 0.275 mm
Barrel Face Offset 4 0.0 mm
Ring Face Profile Type 5 barrel
Effective Ring Face Height 5 0.478 mm
Radius of Curvature of Barrel Face 5 0.275 mm
Barrel Face Offset 5 0.0 mm
Ring Tension 4, 5 82.9 N

 

29

 

Table 3: Ford 5.4 L V8 2 Valve Cylinder Kit Specifications
Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring

Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring # Value Units
Ring Mass 4 0.0091 kg
Ring Modulus of Elasticity 4 2.068E+11 Pa
Ring Poisson’s Ratio 4 0.3
Ring Mass Density 4 7833.5 kg/m3
Ring Conduction Coefficient 4 54.0 W/(m*K)
Ring Coefficient of Thermal Expansion 4 6.33E-06 1/K
Ring Modulus of Elasticity 5 2.068E+11 Pa
Ring Poisson’s Ratio 5 0.3
Ring Mass Density 5 7833.5 kg/m3
Ring Conduction Coefficient 5 54.0 W/(m*K)
Ring Coefficient of Thermal Expansion 5 6.33E-06 1/K
Ring Surface Roughness 4, 5 0.000127 mm
End Gap Clearance 1 0.205 mm
End Gap Clearance 2 0.205 mm
End Gap Clearance 4 0.4 mm
‘° 1 ....
1828:5123: SfirggnR'li‘gtg) of Piston to 2 12.0050 mm
giiflclelérlpgrri Top of Piston to Oil 4, 5 16.99 mm
gfigice Volume Behind Compression 1 241.8 mm3
assggsgtstrgmdw 1 ...... m3
Crevice Volume Behind Compression 2 435.657 mm3

Ring

 

 

 

 

30

 

Table 3: Ford 5.4 L V8 2 Valve Cylinder Kit Specifications
Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring

Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring # Value Units
Land Crevice Volume Below 3
Compression Ring 2 385'812 mm
Volume Behind Oil Control Ring 4, 5 1522.22 mm3
Connecting Rod Length 169.1 mm
Distance from Center of Crank Pin to 0 6582 mm
Connecting Rod Center of Gravity '
Connecting Rod Mass 0.6582 kg
Mass Moment of Inertia of Connecting
Rod About Connecting Rod Center of 90.215 kg*m2
Gravity
Nominal Bore Diameter 90.215 mm
Piston Stroke 105.801 mm
Offset of Crank from Bore Center Line 0.0 mm
Distance from Top of Deck to Top of
Piston When Piston Is at Top-Dead- 3.0023 mm
Center (TDC)
Mass of Piston and Rings 0.359 kg
Mass Moment of Inertia of Piston About 2
Piston Center of Gravity 3'8628E-06 kg*m
Piston Skirt Ovality 0.675 mm
Distance from Bottom of Cylinder to
Bottom of Piston Skirt at 6.50418 mm
Bottom-Dead-Center
Piston Pin Diameter 22.0 mm
Pin Offset in X-Direction -1.0 mm
Pin Offset in Y-Direction 31.0 mm
Piston Diameter 89.2 mm
Piston Height 52.0 mm

 

 

 

 

31

 

Table 3: Ford 5.4 L V8 2 Valve Cylinder Kit Specifications
Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring

Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring # Value Units
X-Coordinate of Piston Center of 0000999 mrn
GraVity
Y-Coordinate of Piston Center of 0.005 mm
GraVity
Thickness of Pin Boss 21.575 mm
Thickness of Crown 8.0 mm
Piston Modulus of Elasticity 7.9979E+10 Pa
Piston Poisson’s Ratio 0.33
Piston Mass Density 2698.8 kg/m3
Piston Conduction Coefficient 161.0 W/(m*K)
Piston CoeffiCient of Thermal 103305 UK
ExpanSion
Mean Combustion Chamber 478.0 C
Temperature
Mean Sump Temperature 336.0 C
Mean Temperature Behind Compresswn 1 433.0 C
Ring
Mean Land Temperature Below 1 428.0 C
Compressron Ring
Mean Temperature Behind Compressron 2 422.0 C
Ring
Mean Land Temperature Below 2 411.0 C
Compressron Ring
Temperature Behind Oil Control Ring 4, 5 400.0 C
Skirt Height 33.5 mm
Skirt Width 70.0 mm
Skirt Dimension (SHTB) 0.0 mm
Skirt Dimension (SW1) 0.0 mm

 

 

 

 

32

 

Table 3: Ford 5.4 L V8 2 Valve Cylinder Kit Specifications
Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring
Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring # Value Units
Skirt Dimension (SW2) 0.0 mm
SAE Oil Type 30

Table 4: Ford 4.6 L V8 2 Valve Cylinder Kit Specifications
Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring
Rings 4 and 5 = Oil Control Ring Segments

Parameter Ring # Value Units
Number of Compression Rings 2
Number of Oil Rings 1
Piston Groove Height 1 1.524 mm
Piston Groove Width 1 4.5 mm
Piston Groove Diameter 1 80.71 mm
Ring Face Profile Type 1 barrel
Effective Ring Face Height 1 1.22 mm
Radius of Curvature of Barrel Face 1 13.0 mm
Ring Tension l 25.35 N
Ring Mass 1 0.0112101 kg
Ring Modulus of Elasticity 1 9.67810E-i-10 Pa
Ring Poisson’s Ratio 1 0.31
Ring Mass Density 1 7196.8 kg/m3
Ring Conduction Coefficient 1 63.0 W/(m*K)
Ring Coefficient of Thermal Expansion 1 6.55E-06 1/K
Axial Width (Ring Thickness) 1 1.47 mm
Radial Thickness (Ring Width) 1 3.965 mm
Ring Surface Roughness l 5.1E—05 mm

 

 

 

 

33

 

 

Table 4: Ford 4.6 L V8 2 Valve Cylinder Kit Specifications
Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring
Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring # Value Units
Piston Groove Height 2 1.524 mm
Piston Groove Width 2 4.61 mm
Piston Groove Diameter 2 80.48 mm
Ring Face Profile Type 2 taper
Effective Ring Face Height 2 0.923 mm
Ring Slope of Taper Face 2 1.76 deg
Ring Tension 2 27.58 N
Ring Mass 2 0.0116641 kg
Ring Modulus of Elasticity 2 8.94310E+10 Pa
Ring Poisson’s Ratio 2 0.31
Ring Mass Density 2 7196.80 kg/m3
Ring Conduction Coefficient 2 63.0 W/(m*K)
Ring Coefficient of Thermal Expansion 2 6.55000E-06 l/K
Ring Axial Width (Ring Thickness) 2 1.479 mm
Radial Thickness (Ring Width) 2 4.07 mm
Ring Surface Roughness 2 5.1E-05 mm
Piston Groove Height 4, 5 3.02 mm
Piston Groove Width 4, 5 3.508 mm
Piston Groove Diameter 4, 5 82.68 mm
Oil Ring Type 4, 5 Three-Piece
Oil Control Ring Dimension 1 4, 5 2.92 mm
Oil Control Ring Dimension 2 4, 5 2.69 mm
Oil Control Ring Dimension 3 4, 5 0.46 mm
Ring Face Profile Type 4 barrel
Effective Ring Face Height 4 1.0 mm

 

 

 

 

34

 

Table 4: Ford 4.6 L V8 2 Valve Cylinder Kit Specifications
Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring

Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring # Value Units
Radius of Curvature of Barrel Face 4 1.0 mm
Barrel Face Offset 4 0.229 mm
Ring Face Profile Type 5
Effective Ring Face Height 5 0.41 mm
Radius of Curvature of Barrel Face 5 1.0 mm
Barrel Face Offset 5 0.229 mm
Ring Tension 4, 5 82.9 N
Ring Mass 4 0.0091 kg
Ring Modulus of Elasticity 4 2.068E+11 Pa
Ring Poisson’s Ratio 4 0.3
Ring Mass Density 4 7833.5 kg/m3
Ring Conduction Coefficient 4 54.0 W/(m*K)
Ring Coefficient of Thermal Expansion 4 6.33E-06 1/K
Ring Modulus of Elasticity 5 2.068E+11 Pa
Ring Poisson’s Ratio 5 0.3
Ring Mass Density 5 7833.5 kg/m3
Ring Conduction Coefficient 5 54.0 W/(m*K)
Ring Coefficient of Thermal Expansion 5 6.33E-06 1/K
Ring Surface Roughness 4, 5 5.1E-05 mrn
End Gap Clearance 1 0.3556 mm
End Gap Clearance 2 0.4445 mm
End Gap Clearance 4 0.3429 mm
Distance from Top of Piston to 1 6.37 mm

Compression Ring

 

 

 

 

35

 

Table 4: Ford 4.6 L V8 2 Valve Cylinder Kit Specifications
Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring

Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring # Value Units
Distance from Top of Piston to 2 11.71 mm
CompreSSion Ring
Distance from Top of Piston to Oil
Control Ring 4, 5 16.5 mm
CreVice Volume Behind CompreSSion 1 833.955 mm3
Ring
Land Crevice Volume Below 3
Compression Ring 1 261129 mm
CreVice Volume Behind CompreSSion 2 306.999 mm3
Ring
Land Crevice Volume Below 3
Compression Ring 2 177'l74 mm
Volume Behind Oil Control Ring 4, 5 849.404 mm3
Connecting Rod Length 150.7 mm
Distance from Center of Crank Pin to 50 2 mm
Connecting Rod Center of Gravity '
Connecting Rod Mass 1.109 kg
Mass Moment of Inertia of Connecting
Rod About Connecting Rod Center of 1.99E-06 kg*m2
Gravity
Nominal Bore Diameter 90.198 mm
Piston Stroke 90.0 mm
Offset of Crank from Bore Center Line 0.0 mm
Distance from Top of Deck to Top of
Piston When Piston Is at Top-Dead- 1.82 mm
Center (TDC)
Mass of Piston and Rings 0.1078 kg
Mass Moment of Inertia of Piston About 0.000877 kg *m2

Piston Center of Gravity

 

 

 

 

36

 

Table 4: Ford 4.6 L V8 2 Valve Cylinder Kit Specifications
Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring

Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring # Value Units

Piston Skirt Ovality 0.508 mm
Distance from Bottom of Cylinder to
Bottom of Piston Skirt at 0.0 mm
Bottom-Dead-Center
Piston Pin Diameter 22.0 mm
Pin Offset in X-Direction -1.27 mm
Pin Offset in Y-Direction 31.0 mm
Piston Diameter 89.71 mm
Piston Height 56.39 mm
X-Coordinate of Piston Center of 0.999 mm
GraVity
Y-Coordinate of Piston Center of

. ~5.0 mm
GraVity
Thickness of Pin Boss 5.0 mm
Thickness of Crown 6.955 mm
Piston Modulus of Elasticity 7.9979E+10 Pa
Piston Poisson’s Ratio 0.33
Piston Mass Density 2698.8 kg/m3
Piston Conduction Coefficient 161.0 W/(m*K)
Piston CoeffiCient of Thermal 103305 UK
ExpanSion
Mean Combustion Chamber 204.85 C
Temperature
Mean Sump Temperature 92.85 C
Mean Temperature Behind Compressmn 1 159.85 C
Ring
Mean Land Temperature Below 1 154.85 C

Compression Ring

 

 

 

 

37

 

Table 4: Ford 4.6 L V8 2 Valve Cylinder Kit Specifications
Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring
Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring # Value Units

11:2: Temperature Behind Compression 2 148.85 C

21:33) r1222; gimgrature Below 2 137.85 C
Temperature Behind Oil Control Ring 4, 5 126.85 C

Skirt Height 38.4 mm

Skirt Width 69.6 mm

Skirt Dimension (SHTB) 0.0 mm

Skirt Dimension (SW1) 0.0 mm

Skirt Dimension (SW2) 0.0 mm

SAE Oil Type 30

 

 

 

 

Table 5: Ford 2.3 L 14 2 Valve Cylinder Kit Specifications
Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring
Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring # Value Units
Number of Compression Rings 2
Number of Oil Rings 1
Piston Groove Height 1 1.5301 mm
Piston Groove Width 1 4.49301 mm
Piston Groove Diameter 1 86.9932 mm
Ring Face Profile Type 1 parabolic
Effective Ring Face Height 1 1.47648 mm
Crown Height of Ring Face 1 0.228600 mm
Ring Tension 1 21.75 N
Ring Mass 1 0.0120999 kg

 

 

 

 

38

 

 

Table 5: Ford 2.3 L14 2 Valve Cylinder Kit Specifications

Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring
Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring # Value Units
Ring Modulus of Elasticity 1 9.67808E+10 Pa
Ring Poisson’s Ratio 1 0.31
Ring Mass Density 1 7196.79 kg/m3
Ring Conduction Coefficient 1 63.0 W/(m*K)
Ring Coefficient of Thermal Expansion 1 6.55E-05 l/K
Axial Width (Ring Thickness) 1 1.47648 mm
Radial Thickness (Ring Width) 1 3.94971 mm
Ring Surface Roughness 1 0.000127 mm
Piston Groove Height 2 1.5301 mm
Piston Groove Width 2 4.49301 mm
Piston Groove Diameter 2 86.9932 mm
Ring Face Profile Type 2 taper
Effective Ring Face Height 2 1.07442 mm
Ring Slope of Taper Face 2 0.75 deg
Ring Tension 2 20.2998 N
Ring Mass 2 0.0122343 kg
Ring Modulus of Elasticity 2 8.94307E+10 Pa
Ring Poisson’s Ratio 2 0.31
Ring Mass Density 2 7196.79 kg/m3
Ring Conduction Coefficient 2 63.0 W/(m*K)
Ring Coefficient of Thermal Expansion 2 6.55E-06 1/K
Ring Axial Width (Ring Thickness) 2 1.47648 mm
Radial Thickness (Ring Width) 2 4.0 mm
Ring Surface Roughness 2 0.000127 mm
Piston Groove Height 4, 5 3.04039 mm

 

 

 

 

39

 

Table 5: Ford 2.3 L14 2 Valve Cylinder Kit Specifications

Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring
Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring # Value Units
Piston Groove Width 4, 5 3.50521 mm
Piston Groove Diameter 4, 5 88.9688 mm
Oil Ring Type 4, 5 Three-Piece
Oil Control Ring Dimension 1 4, 5 2.91059 mm
Oil Control Ring Dimension 2 4, 5 2.48920 mm
Oil Control Ring Dimension 3 4, 5 0.407417 mm
Ring Face Profile Type 4 Composite
Effective Ring Face Height 4 0.406401 mm
Ring Face Parameter X1 4 0.0508001 mm
Ring Face Parameter X2 4 0.0508001 mm
Ring Face Parameter X3 4 0.0830582 mm
Ring Face Parameter X4 4 0.24892 mm
Ring Face Profile Type 5 Composite
Effective Ring Face Height 5 0.406401 mm
Ring Face Parameter X1 5 0.0508001 mm
Ring Face Parameter X2 5 0.0508001 mm
Ring Face Parameter X3 5 0.0830582 mm
Ring Face Parameter X4 5 0.24892 mm
Ring Tension 4, 5 70.0178 N
Ring Mass 4 0.00798331 kg
Ring Modulus of Elasticity 4 2.06800E+11 Pa
Ring Poisson’s Ratio 4 0.3
Ring Mass Density 4 7833.49 kg/m3
Ring Conduction Coefficient 4 54.0 W/(m*K)
Ring Coefficient of Thermal Expansion 4 6.33E-06 1/K

 

 

 

 

4O

 

Table 5: Ford 2.3 L 14 2 Valve Cylinder Kit Specifications
Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring
Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring # Value Units
Ring Modulus of Elasticity 5 2.06800E+11 Pa
Ring Poisson’s Ratio 5 0.3
Ring Mass Density 5 7833.49 kg/m3
Ring Conduction Coefficient 5 54.0 W/(m*K)
Ring Coefficient of Thermal Expansion 5 6.33E-06 1/K
Ring Surface Roughness 4, 5 0.000127 mm
End Gap Clearance 1 0.304801 mm
End Gap Clearance 2 0.406401 mm
End Gap Clearance 4 0.505461 mm
Distance from Top of Piston to 1 7.03073 mm
Compressron Ring
Distance from Top of Piston to 2 12.3749 mm
Compressron Ring
Distance from Top of Piston to 011 4’ 5 17.2085 mm
Control Ring
CreVice Volume Behind CompreSSion 1 235.595 mm3
Ring
Land Crevice Volume Below 3
Compression Ring 1 189675 mm
CreVice Volume Behind CompreSSion 2 214.306 mm3
Ring
Land Crevice Volume Below 3
Compression Ring 2 12'6731 mm
Volume Behind Oil Control Ring 4, 5 887.601 mm3
Connecting Rod Length 138.621 mm
Distance from Center of Crank Pin to 57 1501 mm
Connecting Rod Center of Gravity '
Connecting Rod Mass 0.649097 kg

 

41

 

Table 5: Ford 2.3 L 14 2 Valve Cylinder Kit Specifications
Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring
Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

Parameter Ring # Value Units
Mass Moment of Inertia of Connecting
Rod About Connecting Rod Center of 5.85258E-06 kg*m2
Gravity
Nominal Bore Diameter 96.0122 mm
Piston Stroke 79.4006 mm
Offset of Crank from Bore Center Line 0.0 mm

 

Distance from Top of Deck to Top of

 

 

 

Piston When Piston Is at Top-Dead- 4.06401 mm
Center (T DC)

Mass of Piston and Rings 0.130182 kg
Mass Moment of Inertia of Piston About 2
Piston Center of Gravity 102425-06 kg*m
Piston Skirt Ovality 0.0 mm

 

Distance from Bottom of Cylinder to
Bottom of Piston Skirt at 11.778 mm
Bottom-Dead-Center

 

 

 

 

 

 

 

 

 

 

 

Piston Pin Diameter 23.1648 mm
Pin Offset in X-Direction -l.524 mm
Pin Offset in Y-Direction 34.1910 mm
Piston Diameter 95.9792 mm
Piston Height 66.7005 mm
X-Coordinate of Piston Center of

. 1.524 mm
Grav1ty
Y-Coordinate of Piston Center of

. 19.05 mm
Grav1ty
Thickness of Pin Boss 5.00127 mm
Thickness of Crown 6.99771 mm
Piston Modulus of Elasticity 7.99793 Pa

 

 

 

 

42

 

Table 5: Ford 2.3 L 14 2 Valve Cylinder Kit Specifications
Ring 1 = Top Compression Ring
Ring 2 = Second Compression Ring
Rings 4 and 5 = Oil Control Ring Segments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring # Value Units
Piston Poisson’s Ratio 0.33
Piston Mass Density 2698.8 kg/m3
Piston Conduction Coefficient 161.0 W/(m* K)
Piston CoeffiCient of Thermal 103305 UK
ExpanSion
Mean Combustion Chamber 454.444 C
Temperature
Mean Sump Temperature 93.8889 C
Mean Temperature Behind Compressmn 1 203.889 C
Ring
Mean Land Temperature Below 1 176.111 C
Compressron Ring
Mean Temperature Behind Compressmn 2 162.778 C
Ring
Mean Land Temperature Below 2 148.333 C
Compressmn Ring
Temperature Behind Oil Control Ring 4, 5 135.0 C
Skirt Height 47.9553 mm
Skirt Width 70.9931 mm
Skirt Dimension (SHTB) 15.6972 mm
Skirt Dimension (SW1) 40.9449 mm
Skirt Dimension (SW2) 21.3614 mm
SAE Oil Type SAE Grade 30

 

 

 

 

 

 

5.5 Gas Pressure Input Data
The RING program of the Cylinder kit Analysis System for Engines requires

in-cylinder combustion pressure over the entire engine cycle as an input; it is required to

perform ring pack performance calculations. These in-cylinder combustion pressures for

43

this study were obtained from another simulation program called General Engine
Simulation (GESIM).

The GESIM program, a part of Ford Motor Company’s ENGine SIMulation
system (ENGSIM), simulates in-cylinder flow (in the combustion chamber), heat transfer,
and thermodynamics for both motoring and firing conditions. Pressure points were
generated for engine speeds varying from 1000 to 5000 RPM in 500 RPM increments and
engine loads from 0 (full load) to 558.8 mm (idling) of manifold vacuum with 50.8 mm

increments for all engines.

5.6 Ring Geometry Input Data

5.6.1 Primary Parametric Study
The original piston ring geometry for each ring and engine is shown in Table 3,

Table 4 and Table 5. Piston ring dimensions were altered to measure their influence on

engine blowby performance. The test matrices are given in Table 6, Table 7 and Table 8.

Table 6: Ford 5.4 L V8 Engine Top Compression Ring Test Matrix

 

Parameter Values

 

 

End Gap Clearance 0.3, 0.5, 0.7, 0.9
Axial Width 1.46, 1.47, 1.48, 1.49, 1.50, 1.51, 1.52
Radial Thickness 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0

 

 

 

 

 

 

Table 7: Ford 4.6 L V8 Engine Top Compression Ring Test Matrix

 

Parameter Values

 

 

End Gap Clearance 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3
Axial Width 1.48, 1.49, 1.50, 1.51, 1.52
Radial Thickness 4.1, 4.3, 4.5, 4.7

 

 

 

 

 

 

Table 8: Ford 2.3 L 14 Engine Top Compression Ring Test Matrix

 

Parameter Values

 

 

End Gap Clearance 0.4, 0.5, 0.6, 0.7, 0.9
Axial Width 1.47, 1.48, 1.49, 1.50, 1.51, 1.52
Radial Thickness 4.0, 4.1, 4.2, 4.3, 4.4

 

 

 

 

 

 

In reading these tables, one notices that the parametric values vary from engine to engine.
The same values often could not be selected in some instances due to geometric conflicts.
That is, there are geometric constraints such as groove width, groove diameter, and bore
diameter preventing certain geometries from being tested. The increments varied
depending upon the rate at which blowby performance was affected.

Unfortunately due to the nature of this study, it was physically impossible to
modify single parameters independently. The ring end gap clearance cannot be modified
without also changing the ring mass and the flow area through gap. Ring tension and ring
mass increase proportionally as axial width increases. Increasing radial thickness
decreases the crevice volume behind the ring and increases ring mass. These by-product

parameters made data analysis more challenging, but not impossible.

5.6.2 Secondary Parametric Study
A mini-study was performed to observe the effects (if any) that the second

compression ring had on the overall gas sealing performance of the ring pack. The test

matrix is given below.

Table 9: Ford 5.4 L V8 Engine Top and Second Compression Ring Test Matrix

 

Parameter Values

 

 

 

 

 

End Gap Clearance 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9

 

45

5.7 Bore, Piston, and Connecting Rod Data

Piston groove dimensions were altered to measure their influence on engine

blowby performance. The test matrices are given in Table 10, Table 11 and Table 12.

Table 10: Ford 5.4 L V8 Engine Top Piston Groove Test Matrix

 

 

 

 

 

 

 

Parameter Values
Groove Height 1.46, 1.47, 1.48, 1.49, 1.50, 1.51, 1.52, 1.54, 1.55
Groove Diameter 82.00, 82.40, 82.60, 82.80, 83.00, 83.20

 

Table 11: Ford 4.6 L V8 Engine Top Piston Groove Test Matrix

 

 

 

 

Parameter Values
Groove Height 1.48, 1.49, 1.50, 1.51, 1.52
Groove Diameter 80.91, 81.11, 81.31, 81.51, 81.71, 81.91, 82.11, 82.20

 

 

 

 

Table 12: Ford 2.3 L V8 Engine Top Piston Groove Test Matrix

 

 

 

 

 

 

 

Parameter Values
Groove Height 1.49, 1.50, 1.51, 1.52, 1.54
Groove Diameter 87.10, 87.30, 87.50, 87.70, 87.90

 

The groove dimensions, like the ring dimensions, also had “by-product”
parameters. An increase in groove height resulted in an increase in crevice volume. As the
groove diameter was increased, the crevice volume decreased. Additionally, groove width
had to decrease as groove diameter increased, so that piston diameter would not have to
increase. Thus, the groove became shallower, as groove diameter was increased.
Neglecting these by-product parameters would make analysis of the results nonsensical.
5.8 Ring TWist

In real engines, the piston rings with non-symmetric cross sections “twist” in

their groove throughout the engine cycle. Thus, the ring not only moves axially, but

46

different sections of the rings twist and occupy different axial locations at the same
instance of time. The phenomenon of ring twist affects gas flow areas and ring wear
patterns. Although the TWIST program in the Cylinder kit Analysis System for Engines,
supports ring twist simulation, it was not utilized in this study due to technical
complications.

In order for ring twist to be accounted for in the simulations several issues
would have to be resolved. The most challenging of these issues would be to develop an
automated finite element gridding program. Piston rings vary greatly in size and shape,
thus making it difficult to code an algorithm to produce an evenly-sized grid, utilizing
quadrilaterals and triangles of proper aspect ratio (elements that are not extremely narrow
or skewed). The second technical issue was the large amount of computer cycles that
would be required to generate stiffness matrices from the finite element grid, and 3-D ring
positions from the force vectors. With a Pentium III 500 MHz processor, it takes between
three to seven hours (depending upon the presence of ring collapse) to compute fully ring
pack performance with twist for one operating point. The ring twist analysis would have to
be done separately for each of the 117 operating conditions multiplied by the several
cylinder kit designs; it may have taken up to one year of computer time to calculate the
data points for this study. However, in the near future, computing technology may make
the full ring twist analysis for the entire engine operating maps economically and
temporally feasible.

Due to the circumstances explained above, ring twist was omitted from this

study. Fortunately, the piston ring cross sections for this study were almost perfectly

47

rectangular and symmetric (radially and axially), meaning that the extent of ring twist

presence in these cases are not a strong influence even in the real engine.

48

CHAPTER 6. COMPUTER SIMULATION RESULTS

6.1 Overview

In all instances, the Ford 4.6 L V8 engine had the worst blowby performance of
the three engines. The Ford 5.4 L V8 engine had the most unstable ring pack; that is, it
collapsed the most often. The Ford 2.3 L 14 engine had the most desirable blowby
performance and stability.
6.2 Plots

Due to the large volume of relevant plots produced in this parametric study, the
complete set of blowby map plots has been included in Appendix A (Chapter 10).

Images in this thesis are presented in color.

49

CHAPTER 7. COMPUTER SIMULATION ANALYSIS

7.1 Blowby Map Analysis

Blowby maps can provide useful information on the performance of piston ring
packs for a range of operating conditions. By comparing multiple different blowby maps,
one can observe the degree of influence certain parameters have on blowby performance.

In general, nominal engine performance is characterized by the following traits
on blowby maps:

As engine speed increases, blowby increases.

Engine speed has more influence on blowby at higher engine loads.
As engine load increases, blowby increases.

Engine load has more influence on blowby than engine speed.

The blowby map forms an almost perfectly smooth plane.
Figure 14 illustrates the shape of a typical blowby map for an engine.

MPPNr-

 

Increasing Blowby

 

 

   

. l oad
n6
lncreasmg Eng‘

   

 

 

 

Figure 14: Typical Blowby Map

The crosshatched region in Figure 14 indicates area of “normal ring

performance.” The dotted region represents the area that is the most likely to have ring

50

collapse. Ring collapse in blowby maps is usually detected by a cone, or ridge protruding

sharply from the plane. Minor bumps and ridges are usually signs of ring fluttering.

7.2 General Observations

7.2.1 Effect of Blowby Magnitude on Parameter Sensitivity
Typically, the greater the blowby at an operating condition, the greater the

influence parameter variations had on the sealing performance. Therefore, the degree of
impact of parameter variations can easily be gauged by observing the operating conditions
of highest engine loads and engine speeds, and operating conditions attributed with ring
collapse.

A comparison of the plots in Heading 10.2, Heading 10.3 and Heading 10.4
reveals the differing parameter sensitivity characteristics of the three engines studied. The
4.6 L engine had the overall highest blowby, and thus had the most parameter sensitivity.
Since the overall blowby was relatively low in the 2.3 L engine, most of the parametric
effects could only be observed qualitatively at the operating conditions with highest
blowby.

7.2.2 Note on Engine Comparisons

Comparisons between the three engines in this study cannot be made directly
without taking special considerations. Factors such as compression ratio and stroke can
strongly affect the results. Thus, when comparing the engines, one should analyze their
trends and not their magnitudes.

The 2.3 L cylinder kit appeared to have the best performance and stability of
the three engines. However, the in-cylinder peak pressure was also significantly lower than

that of the other engines. The 4.6 L cylinder kit’s poor blowby performance was attributed

51

primarily to its high in-cylinder peak pressure. While theoretical thermodynamics dictates
that higher compression ratios lead to higher engine efficiency, in practice, higher
compression ratios sometimes lower sealing efficiencies.

The 5.4 L cylinder kit is interesting because its overall blowby performance
and compression ratio lies between the two other engines, but its ring pack stability is also
the worst. Its longer stroke contributes to inertial effects, bringing ring collapse into its
operating conditions set. Changing stroke and compression ratio can move ring collapse
inside or outside an engines operating conditions.

7.3 End Gap Analysis

Agreeing with Wentworth’s [12] results, the plots in Heading 10.2.2,
Heading 10.3.2 and Heading 10.4.2 show that blowby smoothly increased at all operating
points for all the engines as the top ring end gap increased. This observation may at first
seem obvious, because the flow area is being increased. However, if one also examines the
inertial effects, this observation may no longer be trivial.

Coinciding with Equation (45), a reduction in ring gap caused a reduction in
blowby in operating conditions with ring collapse. As explained in Heading 3.4, if the ring
gap is sufficiently small, the two ends of the ring butt together during ring collapse,
thereby preventing the ring from collapsing all the way.

As the ring gap is increased, the amount of ring material is decreased.
Decreases in ring mass tend to improve ring pack sealing performance by reducing the
likelihood of ring collapse (see Heading 3.4). In studying the plots in Heading 10.4.2, the

number of operating conditions with ring collapse was shown to become worse when the

52

end gap was reduced. Thus, an unknown ring destabilizing factor was present. A

mini-study was performed to discover this unknown influence.

7.3.1 Mini-Study on 5.4 L V8 Ford Motor Company Engine
The mini-study showed that the second ring sealing performance had a strong

effect on the top ring sealing performance, under certain conditions. According to the plots
in Heading 10.5, opening the end gap wider for the second compression ring did not
significantly increase blowby for most operating conditions. However, widening the
second ring end gap increased the piston ring stability; the number of operating points
with ring collapse was higher when the top compression ring end gap was exclusively
increased.

The cause of this behavior is related to the forces exerted on the top ring. Gas
flows into the piston land below the top ring. Since the second ring end gap is smaller than
that of the top ring, the gases are not allowed to flow past the second ring as easily. Thus,
pressure increases in the volume between the top and second ring, which in turn generates
a force upward on the top ring. This upward force combined with the inertial effects
accelerates the piston ring toward the top of its groove. As explained in Heading 3.4, if the
top piston ring arrives at the top of its groove late in the compression stroke, the conditions
are likely to lead to ring collapse. Therefore, if ring collapse is problematic for a given ring
pack, the second ring end gap can be increased to improve the ring pack’s stability without
severely degrading the ring pack performance.

One important aspect to note is that increasing the second ring end gap has an
additional undesirable effect. Besides slightly increasing the blowby at each operating

point, operating points with ring collapse had significantly higher blowby—as shown in

53

 

Rhg Motion vs. Crank Angle
51L 2 Volvo VB Ford Engho - 5000 RPM. 12" Mallow Vacuum
iooem 744* 1”,. ~ ~ 77 ,, 7 L, iv~~7 fl ,_ mu...
:fifi? 1.
.m V - O -SoconaRingtI”
' ' t9fl"‘9_J .

  

0 DOS 900
90 wt) 270 $0 ‘50 5‘0 630 720
Grant We (damn)

 

 

 

Figure 15: Ring Motion Versus Crank Angle (Ring Collapse)

Figure 86 and Figure 126. The blowby magnitudes in the case of ring collapse are higher
because the larger second ring gap allows for an increased flow rate. In these instances, the
second compression ring sometimes collapsed as the additional gas flowed through the
second ring end gap. This flow accumulated pressure below the second ring. This pressure
below the second ring can force the ring to the top of its groove near the end of
compression. Thus, following a top ring collapse, the second ring may also collapse if the
second ring gap is too large.

It is important to note that from this mini-study, one can see that anytime that
the second ring seals better than the top ring, the force balance would tend to favor a ring
collapse condition. Although it initially seems absurd to expand the ring gap (under
certain conditions) to improve blowby performance, others such as Viceino [13] and

Federal Mogul [14] hypothesized similar explanations.

54

7.3.2 Note of Caution
Although reducing the end gap improves both general performance and

performance during ring collapse, there exists a lower limit for the ring gap. If the ring gap
is too small, thermal expansion can cause the ends of the ring to butt together and cause
extreme ring and liner wear. All of the dimensions run in the simulations are assumed to
be “warm” dimensions. Therefore, actual compression ring end gap designs would be
larger than the “warm” dimensions.

7.4 Axial Width Analysis

Axial width for the top compression ring had only an almost negligible
influence on blowby performance. Blowby decreased very slightly as the axial width of
the piston ring was reduced. When the axial width of the ring approached 10 to 20 microns
of its ring groove height, “ridges” appeared on the blowby map indicating ring collapse.

As axial width is increased, the flow path through the piston groove is reduced.
Reducing the flow path, reduces the blowby passing behind the piston groove. If the flow
path between the groove and the ring is reduced too much, the pressure drop across the top
of the ring leads to ring collapse.

As mentioned in Heading 5.6, the ring tension is increased as axial thickness
increases. Ring tension is a relatively insignificant factor in preventing ring collapse, but
increased ring tension is known to accelerate ring wear. Although the ring tension is only
increased slightly by altering the axial width, it possesses a slight adverse effect on ring
lifespan.

Another undesirable side-effect of increasing the ring’s axial width is that the
ring’s inertia increases. Increasing a ring’s inertia often increases the probability of ring

collapse, as explained in Heading 3.4.

55

7.5 Groove Height Analysis
Altering the groove height seems similar to altering the axial width in that they

both change the axial clearance. Unlike varying the axial width, varying groove height
does not change the ring’s inertia. Varying the groove height changes the crevice volume
behind the ring and of the adjacent lands.

According to the blowby maps in Heading 10.2.4, Heading 10.3.4, and
Heading 10.4.4, blowby at almost all operating conditions slightly increases as groove
height increases. The larger groove height, provides a larger crevice volume for
combustion gases to flow into.

Under the operating conditions with ring collapse, the ring collapse peak in the
blowby maps decreases slightly as ring groove height increases. These smaller peaks are
an effect of the ring collapse conditions lasting for a shorter duration of time. The larger
ring clearance allows for gases to flow behind the ring groove with less pressure drop.
Consequently, the support behind the ring from the gases is improved.

The unusual shape of the blowby map shown in Figure 62 is due to ring flutter.
In this instance, ring flutter does not cause its characteristic degradation in ring pack
sealing performance. The small ring clearance prevents the usual flow of gases behind the

ring groove.

7.6 Small Clearance Between Top of Ring and Top of Groove
It is interesting to note that while a small ring clearance by means of a large

axial width results in ring collapse, the same ring clearance by means of a small groove
height results in improved ring performance. Hence, it is better to design a thin ring with a
small ring clearance, than to design a thick ring with a small ring clearance; the latter

design has more inertia.

56

 

 

Reducing ring clearance also has the additional advantage of reducing the
effects of the piston ring impacting on its groove. The ring momentum becomes less,
because the ring has less distance to achieve a state of high kinetic energy. Large piston

ring clearances result in ring and groove characteristics as shown in Figure 16.

 

I Excessive Wear

 

 

 

 

 

 

 

 

Figure 16: Aged Piston Ring and Groove with Large Clearance

7 .7 Radial Thickness Analysis
Heading 10.2.5, Heading 10.3.5 and Heading 10.4.5 suggest that increased

radial thickness significantly improves ring sealing performance. The increased radial
thickness reduces the crevice volume behind the compression ring. Thus, the amount of
combustion gases that can be trapped behind the ring is reduced. Furthermore, if the ring
has a relatively small clearance between the inner ring diameter and the inner groove

diameter, the ring is prevented from fully collapsing under the ring collapse conditions.

 

Ring Collapse Interference . I

 

 

 

 

 

 

 

 

Figure 17: Ring Collapse Interference

57

Other than slightly increasing ring material, there is no drawback to having a
larger radial thickness. However, radial thickness does have an upper limit. The piston ring
radial thickness, when “warm,” must not reduce the clearance behind the ring to zero—

otherwise excessive wear or seizure will occur.

7.7.1 Relating Ring Wear to Radial Thickness
Over the lifetime of a piston ring, its radial thickness begins to decrease due to

ring wear. The plots in Heading 10.2.5, Heading 10.3.5 and Heading 10.4.5 each show a
close representation of the reverse progression of a ring performing as it ages. The ring

wear simulation would be better if the minor increase in end gap were taken into account.

7 .8 Groove Diameter Analysis

7.8.1 Basic Overview
The figures in Heading 10.2.6, Heading 10.3.6, and Heading 10.4.6 show that

blowby was reduced as groove diameter increases for all operating conditions with the
exceptions of Figure 117 and Figure 118.

The cause of the sealing improvement is similar to the cause explained in
Heading 7.5. That is, the smaller crevice volume restricts flow behind the top compression
ring. However, the change in performance differs in the two following ways: increasing
the groove diameter, makes the groove more shallow; changing the groove diameter does

not affect the ring mass.

7.8.2 Exceptions to the Rule
As the groove diameter increases, the ring grooves become more shallow.

Consequently, the flow path behind the groove is shorter. A shorter flow path makes it

easier for gases to flow behind the ring if the ring flutters. In both Figure 117 and

58

Figure 118 where ring collapse is detected, the top ring is observed to drop partially in its

groove, momentarily following spark. During this dip (see Figure 18), gas easily flows

 

Ring lotion vs. Crank Anglo
5.4L 2 Valve V8 Ford Engho - 5000 RP", 12" Mlnlold Vacuum

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

100601 -7 7 77——7~——»r ~ A igfirfii~i~ ——A~I
900E021mi77 -.. ”r 7 77*?" m
I I ' .
Boos-021 —7
. b I I
. .
70094): % 7 —A_ ,7. g 7 7 +1?»ng L.__ . 4
I - o -SoeondRirg I
‘5‘ 6002-02 i . 7 VA A — ¥ 7 ‘9‘““7’9 J
- . .
l I
g 500m: . u
a ' 0
E . 0 I . '
I, 4005-02 er4+v *— A V7 i 4——4 77' a
. ' 0
I ' 1
300502 47 4 I —— — . w J
. .
'
.
museum—r __ . I 11
I
. .
iooem ‘ : 4 — ‘ 41
. ’ ' ' A
oooekoo J ‘
so 130 270 360 450 540 630 120

 

 

 

CnnIi Anglo (damn)

 

 

 

Figure 18: Ring Motion Versus Crank Angle (Ring Collapse) With Top Ring Dip

past the top ring. Since the second ring is sealing better than the top ring during the dip,
the land between the top and second ring becomes pressurized. The top ring returns to the
top of its groove, resulting in ring collapse during the power stroke.

Where ring stability is not a significant issue, groove diameter can be increased
until the ring clearance behind the ring is approximately 0.2 mm for automotive gasoline
engines. However, if a ring pack is known to have stability problems, the ring clearance

should not be smaller than 0.4 mm in automotive gasoline engine applications.

59

CHAPTER 8. CONCLUSIONS AND RECOMMENDATIONS

8.1 General Implications
The results from the study performed, indicate that blowby performance

follows a predictable continuous pattern with respect to cylinder kit geometries. For
improvement in blowby performance, geometric parameters can be increased or decreased
until either physical constraints are reached or the ring pack becomes unstable. The ring
pack is considered to be unstable when ring collapse is detected. Thus, advanced
optimization algorithms are not essential in finding the ideal cylinder design.
8.2 Top Ring Trends

The following table summarizes the effect on blowby performance of the tested

geometric parameters as they are increased.

Table 13: Qualitative Parametric Sensitivity
1 designates highest level of influence
5 designates lowest level of influence

 

 

 

 

 

 

 

 

 

 

 

Parameter Ring Pack Stability Sealing Performance
Top Ring End Gap Clearance Decrease - 1 Decrease - 1
Top Ring Axial Width Decrease - 5 Increase - 5
Top Ring Groove Height Increase - 3 Decrease - 4
Top Ring Radial Thickness Increase - 4 Increase - 3
Top Ring Groove Diameter Decrease - 2 Increase - 2

 

To improve ring pack performance without penalty, end gap clearance should
be minimized and radial thickness of the top ring should be maximized. If ring pack
stability is not a significant issue with a particular ring pack, the successive design should

maximize top ring axial width and groove diameter, while minimizing top ring groove

60

height. However, if ring pack stability is problematic, those parameters should be altered

in the way opposing the preceding statement.

8.3 HC Emissions
While this study did not focus on HC emissions in ring pack design, the

reduction of HC emissions are indirectly accounted for in backflow; backflow is a
subcomponent of blowby. Therefore, reducing blowby also lowers HC emissions.

It should be noted that, under normal engine operating conditions, one of the
largest sources of HC emissions comes from crevice volumes. [15] Increasing radial

thickness and groove diameter reduces crevice volumes, and thus decreases HC emissions.

8.4 Top and Second Compression Ring Relation
According to the simulation performed on Ford Motor Company’s 5.4 L V8

engine, the second compression ring has a strong effect on ring pack stability. If the
second ring seals better than the top ring, pressure builds between the top and second
compression ring. This pressure increases the likelihood of ring collapse. Ring collapse
conditions can be alleviated by either improving the top ring’s sealing performance, or

decreasing the second ring’s sealing performance.

8.5 Recommendations
The trends summarized in Heading 8.2 shall prove to be useful to piston and

ring pack designers. The by-product tool (coded for this study) that automates the
simulation over 100 operating conditions should be useful for future studies of other ring
pack geometries.

Ring twist was neglected in this study because both the software and hardware

technology were currently unavailable. While the CASE system offers a ring twist

61

analysis program, it cannot automatically generate a finite element grid. To perform such a
study in a feasible amount of time, a program that automates finite element gridding
would have to be coded. Furthermore on modern computers, stiffness matrices can take up
to two hours to generate for each ring pack.

In the future—when faster computers are less expensive—it will be
economically and temporally feasible to include ring twist analysis in investigations
similar to the one performed in this thesis. Research including ring twist will allow for the
accurate parametric studies of cylinder kit geometries’ effect on ring wear. Blowby
predictions will also better approximate measured blowby values with the implementation
of ring twist into cylinder kit parametric experiments.

Although the CASE system simulation has proved to be an accurate predictor
of cylinder kit performance, the results require physical testing for absolute confirmation.
Future efforts should be made to verify some of the piston ring configuration

performances analyzed in this study.

62

10.

ll.

12.

13.

14.

15.

CHAPTER 9. REFERENCES

Total Seal. Ring Flutter. [Online Available]

http://www.totalseal.com/flutter.htm1, July 9, 2000.

Thompson, N. D. and Wallace, J. 8., “Effect of Engine Operating Variables and
Piston and Ring Parameters on Crevice Hydrocarbon Emissions,” SAE paper
940480, 1994.

Kuo, T., Sellnau, M. C., Theobald, M. A. and Jones, J. D., “Calculation of Flow in
the Piston-Cylinder-Ring Crevices of a Homogeneous-Charge Engine and
Comparison with Experiment,” SAE paper 890838, 1989.

Ellemian, J ., Rohrle, and M. D., Schelling, H., “Oil Consumption and Blowby of
Truck Diesel Engines—Test Bench Results,” SAE paper 810937, 1981.
Mid-Michigan Research, “CASE Theoretical Manual,” Mid-Michigan Research,
1998.

Ejakov, M. A., Schock, H. J., Brombolich L. J., Carlstrom, C. M. and Williams, R.
L., “Simulation Analysis of Inter-Ring Gas Pressure and Ring Dynamics and Their
Effect on Blow-by,” ASME paper 97-ICE-50, 1997.

Yun, J. E., Chung, Y., Chun, S. M., and Lee, K. Y., “Study of a Piston Ring
Assembly Design through Experimental and Numerical Investigation of Inter-Ring
Gas Pressure and Blowby in a Four-Stroke SI Engine,” SAE paper 958524, 1995.
Heywood, J. B., “Internal Combustion Engine Fundamentals,” McGraw-Hill, Inc.,
1988.

Truscott, R. T., Reid, T. and Ruddy, B., “Ring Dynamics in a Diesel Engine and Its
Effect on Oil Consumption and Blowby,” SAE paper 831282, 1983.

Cengel, Y. A. and Boles, M. A., “Thermodynamics an Engineering Approach,”
Third Edition, McGraw-Hill, Inc., 1998.

Cook, C. L., Power Piston Ring Performance. [Online Available]
http://www.tfhudgins.com/cook/faq/faq3.html, March 19, 1997.

Wentworth, J. T., “Effect of Top Compression Ring Profile on Oil Consumption and
Blowby with the Sealed Ring-Orifice Design,” SAE paper 820089, 1982.

Viceino, D., Piston Ring Technology - Sophistication or Necessity. [Online
Available]

http://members.aera.org/EngineTech/edge1296/page3.htm, June 29, 2000.

Federal Mogul, Piston Ring Technology. [Online Available]
http://www.federalmogul.com/products_main/am_underhood/
piston_rings_speed_pro.htm, June 29, 2000.

Dent, J. C. and Lakshiminarayana, P. A., “A Model for Absorption and Desorption of
Fuel Vapor by Cylinder Lubricating Oil Films and Its Contribution to Hydrocarbon
Emissions,” SAE paper 830652, 1983.

63

CHAPTER 10. APPENDIX A

10.1 Note About Blowby Scale
The blowby maps shown in the headings below have the same blowby scale for

each engine of the same parametric study. The end gap variation map sets have the same
scale for the 2.3 L 14, 4.6 L V8 and 5.6 L V8 Ford engines, but a differing scale from the
groove height variations map set for these same engines. Due to the size of the plots, it
would be difficult to analyze some plots if all of the scales were identical for all of the

parametric studies.

10.2 Parametric Study Plots for Ford 2.3 L 14 Engine
The Ford 2.3 L I4 engine parametric study blowby maps are included on the

following pages.
All of the geometric dimensions are in millimeters unless otherwise specified.
Ring 1 refers to the top compression ring, and Ring 2 refers to the second compression

ring.

10.2.1 Original Design

 

2.3L in Ford sum-0mm Oahu

 

 

 

Figure 19: Ford 2.3 L 14 Engine Blowby Map - Original Design
0.305 End Gap Ring 1
1.476 Axial Width Ring 1
1.53 Groove Height Ring 1
3.95 Radial Thickness Ring 1
86.933 Groove Diameter Ring 1

10.2.2 End Gap Variations

 

 

2.3LMFordEnghn-OAEMW1

 

 

Figure 20: Ford 2.3 L 14 Engine Blowby Map - 0.4 End Gap Ring 1

65

 

 

 

”LIMEnoIIO-OJEndbl

 

 

Figure 21: Ford 2.3 L 14 Engine Blowby Map - 0.5 End Gap Ring 1

 

 

uumm-usnuo-pi

 

 

Figure 22: Ford 2.3 L 14 Engine Blowby Map - 0.6 End Gap Ring 1

 

 

ULHFWEn'lu-OJEMIM1

 

 

Figure 23: Ford 2.3 L 14 Engine Blowby Map - 0.7 End Gap Ring 1

 

 

”LuFoniEngho-OJEMGQ1

 

 

Figure 24: Ford 2.3 L 14 Engine Blowby Map - 0.8 End Gap Ring 1

67

 

 

 

ISLMFUIIEngIn-OJEMIGQ1

 

 

 

Figure 25: Ford 2.3 L14 Engine Blowby Map - 0.9 End Gap Ring 1
10.2.3 Axial Width Variations

 

 

uLMFuflEngho-tATAIUVMIH

 

 

 

Figure 26: Ford 2.3 L14 Engine Blowby Map - 1.47 Axial Width Ring 1

68

 

MLKFWEnghO-lflAlthl

 

 

Figure 27: Ford 2.3 L 14 Engine Blowby Map - 1.49 Axial Width Ring 1

 

 

uLHFmEn'hIo-1JOAIHM1

 

 

Figure 28: Ford 2.3 L 14 Engine Blowby Map - 1.50 Axial Width Ring 1

69

 

 

 

ZJLMFudEllgho-tMAIHMl

 

 

Figure 29: Ford 2.3 L 14 Engine Blowby Map - 1.51 Axial Width Ring 1

 

 

mumm-rawmr

 

 

Figure 30: Ford 2.3 L14 Engine Blowby ap - 1.52 Axial Width Ring 1

70

 

10.2.4 Groove Height Variations

 

 

2.3L M Ford mm- m mm mm 1

 

 

Figure 31: Ford 2.3 L 14 Engine Blowby Map — 1.49 Groove Height Ring 1

 

 

MLMForIIEngho-1.5OWIHOI9M1

 

 

Figure 32: Ford 2.3 L 14 Engine Blowby Map - 1.50 Groove Height Ring 1

71

 

 

 

 

ZJLKFWEri'h-lmmmflifl

 

 

Figure 33: Ford 2.3 L 14 Engine Blowby Map - 1.51 Groove Height Ring 1

 

 

murmmm-uzovmwu

 

 

Figure 34: Ford 2.3 L14 Engine Blowby Map - 1.52 Groove Height Ring 1

72

 

 

 

 

murmmm-iumwi

 

 

 

 

Figure 35: Ford 2.3 L 14 Engine Blowby ap - 1.54 Groove Height Ring 1
10.2.5 Radial Thickness Variations

 

lSLIlFonlEnfihc-tommm‘l

 

 

Figure 36: Ford 2.3 L 14 Engine Blowby Map — 4.0 Radial Thickness Ring 1

73

 

 

qumm-ttMM‘l

 

 

Figure 37: Ford 2.3 L 14 Engine Blowby Map - 4.1 Radial Thickness Ring 1

 

 

uLumen-ummmi

 

 

Figure 38: Ford 2.3 L14 Engine Blowby Map - 4.2 Radial Thickness Ring 1

74

 

 

mMFwEmM-anm1

 

 

Figure 39: Ford 2.3 L 14 Engine Blowby Map - 4.3 Radial Thickness Ring 1

 

 

”LKFWEngho-Mfllfilmml

 

 

Figure 40: Ford 2.3 L 14 Engine Blowby Map - 4.4 Radial Thickness Ring 1

75

 

10.2.6 Groove Diameter Variations

 

 

 

 

 

 

 

Figure 42: Ford 2.3 L14 Engine Blowby Map - 87.30 Groove Diameter Ring 1

76

 

 

 

 

Figure 43: Ford 2.3 L 14 Engine Blowby Map - 87.50 Groove Diameter Ring 1

 

 

DLHFordEngln-WJOMDMI

 

 

Figure 44: Ford 2.3 L 14 Engine Blowby Map - 87.70 Groove Diameter Ring 1

77

 

 

uLMFoMEnoho-UMMDM1

 

 

 

 

Figure 45: Ford 2.3 L 14 Engine Blowby Map - 87.90 Groove Diameter Ring 1

10.3 Parametric Study Plots for Ford 4.6 L V8 Engine
The Ford 4.6 L V8 engine parametric study blowby maps are included on the

following pages.

78

10.3.1 Original Design

 

 

4.6L V3 Ford Emit. - (”I'M DOV!

    

a
°§§§a

 

Figure 46: Ford 4.6 L V8 Engine Blowby Map - Original Design
0.356 End Gap Ring 1
1.470 Axial Width Ring 1
1.524 Groove Height Ring 1
3.965 Radial Thickness Ring 1
80.71 Groove Diameter Ring 1

10.3.2 End Gap Variations

 

 

 

“LVBFWEngho-OAEMIGQ1

lowly] (ms)

       

N
go.
a
°n§ n
F) 'n
.e~

 

Figure 47: Ford 4.6 L V8 Engine Blowby Map - 0.4 End Gap Ring 1

79

 

 

 

«inseam-Mamie.“

 

 

Figure 48: Ford 4.6 L V8 Engine Blowby Map - 0.5 End Gap Ring 1

 

 

LILVOFovdEnoho-OJEndul

 

 

Figure 49: Ford 4.6 L V8 Engine Blowby Map - 0.6 End Gap Ring 1

80

 

 

LILVIFOMEMN-OJEMOQl

 

 

Figure 50: Ford 4.6 L V8 Engine Blowby Map - 0.7 End Gap Ring 1

 

 

LILVIFodElloho-OJEIIGGQ‘I

 

 

Figure 51: Ford 4.6 L V8 Engine Blowby Map - 0.8 End Gap Ring 1

81

 

 

t‘LVIFoMEngho-OJEndawl

 

 

Figure 52: Ford 4.6 L V8 Engine Blowby Map - 0.9 End Gap Ring 1

 

 

‘JLVIFovdEnghu-LOEMGQ‘I

 

 

Figure 53: Ford 4.6 L V8 Engine Blowby Map - 1.0 End Gap Ring 1

82

 

 

tCLVIFou‘IEnoho-‘IJEMGQH

 

 

Figure 54: Ford 4.6 L V8 Engine Blowby Map — 1.1 End Gap Ring 1

 

 

4.0LVIFovdEnoho-12EMGQ1

 

 

Figure 55: Ford 4.6 L V8 Engine Blowby Map - 1.2 End Gap Ring 1

83

 

 

 

tILVIFordEngho-1JEiidG-p1

 

 

Figure 56: Ford 4.6 L V8 Engine Blowby Map - 1.3 End Gap Ring 1
10.3.3 Axial Width Variation

 

 

LOLVBFordEnoho-‘IAIAIHM‘I

 

 

Figure 57: Ford 4.6 L V8 Engine Blowby Map - 1.48 Axial Width Ring 1

84

 

 

 

cuwrwmm-rmmmr

 

 

Figure 58: Ford 4.6 L V8 Engine Blowby Map - 1.49 Axial Width Ring 1

 

 

LILVIFwdEmho-IMWWHM

 

 

Figure 59: Ford 4.6 L V8 Engine Blowby Map — 1.50 Axial Width Ring 1

85

 

 

tuVlFoMEnflho-‘IJ1AIUM1

 

 

Figure 60: Ford 4.6 L V8 Engine Blowby Map - 1.51 Axial Width Ring 1

 

 

£6LV8FadEnghn-152AIUM1

 

 

Figure 61: Ford 4.6 L V8 Engine Blowby Map - 1.52 Axial Width Ring 1

86

 

10.3.4 Groove Height Variation

 

t8LVBFoMEngho-1Alcroovoflol'hl1

   
     

2a

m
a:
9’.
u

 

Figure 62: Ford 4.6 L V8 Engine Blowby Map - 1.48 Groove Height Ring 1

 

 

t‘LWFWEflgm-lflmflomfl

 

 

Figure 63: Ford 4.6 L V8 Engine Blowby Map - 1.49 Groove Height Ring 1

87

 

 

LILVIFOI'dEngho-LGOOIWONOUIM

 

 

Figure 64: Ford 4.6 L V8 Engine Blowby Map - 1.50 Groove Height Ring 1

 

 

ACLVSFordEn'ho-‘IM mumi

 

 

Figure 65: Ford 4.6 L V8 Engine Blowby Map - 1.51 Groove Height Ring 1

88

 

 

 

mWFaflEngho-‘IJIMHMH

 

 

Figure 66: Ford 4.6 L V8 Engine Blowby Map - 1.52 Groove Height Ring 1
10.3.5 Radial Thickness Variations

 

 

«or. vs Foul Engho -4.1Radl|l1hldtnou 1

 

 

Figure 67: Ford 4.6 L V8 Engine Blowby Map — 4.1 Radial Thickness Ring 1

89

 

 

 

mnmmw-ummi

 

 

Figure 68: Ford 4.6 L V8 Engine Blowby Map - 4.3 Radial Thickness Ring 1

 

 

ACLWFMEn'hn-umnml

 

 

Figure 69: Ford 4.6 L V8 Engine Blowby Map - 4.5 Radial Thickness Ring 1

 

 

 

LILVIFWEm-‘JMTIIHM‘I

 

 

Figure 70: Ford 4.6 L V8 Engine Blowby Map - 4.7 Radial Thickness Ring 1

10.3.6 Groove Diameter Variations

 

 

mvarmm-aommnumi

 

 

Figure 71: Ford 4.6 L V8 Engine Blowby Map - 80.91 Groove Diameter Ring 1

91

 

 

 

annrwmm-ummmr

 

 

Figure 72: Ford 4.6 L V8 Engine Blowby Map — 81.11 Groove Diameter Ring 1

 

 

mnrmsm-aurmnmr

 

 

Figure 73: Ford 4.6 L V8 Engine Blowby Map - 81.31 Groove Diameter Ring 1

92

 

 

LSLVOFordEngho-flmcvoovoDl-IW‘I

 

 

Figure 74: Ford 4.6 L V8 Engine Blowby Map - 81.51 Groove Diameter Ring 1

 

 

LILVB Ford Erratic-01.71 Grow. DM‘I

 

 

Figure 75: Ford 4.6 L V8 Engine Blowby Map - 81.71 Groove Diameter Ring 1

93

 

 

LOLVIFovdEnm-I1J1Gvoovom1

 

 

Figure 76: Ford 4.6 L V8 Engine Blowby Map - 81.91 Groove Diameter Ring 1

 

 

cansmam-aznmnmr

 

 

Figure 77: Ford 4.6 L V8 Engine Blowby Map - 82.11 Groove Diameter Ring 1

94

 

 

utvarwmn-mommr

 

 

 

 

Figure 78: Ford 4.6 L V8 Engine Blowby Map - 82.20 Groove Diameter Ring 1

10.4 Parametric Study Plots for Ford 5.4 L V8 Engine
The Ford 5.4 L V8 engine parametric study blowby maps are included on the

following pages.

95

10.4.1 Original Design

 

sALvnrauEngtn-aigmiouign

 

 

 

Figure 79: Ford 5.4 L V8 Engine Blowby Map - Original Design
0.356 End Gap Ring 1
0.356 End Gap Ring 2
1.45 Axial Width Ring 1
1.53 Groove Height Ring 1
3.4 Radial Thickness Ring 1
82.2 Groove Diameter Ring 1

10.4.2 End Gap Variations

 

 

mwrwm-oasmwi

 

 

Figure 80: Ford 5.4 L V8 Engine Blowby Map - 0.3 End Gap Ring 1

96

 

 

 

SALVIFMEngho-Olindb1

 

 

Figure 81: Ford 5.4 L V8 Engine Blowby Map - 0.4 End Gap Ring 1

 

 

MLVIFfldElIfllo-OJEMM‘I

 

 

Figure 82: Ford 5.4 L V8 Engine Blowby Map - 0.5 End Gap Ring 1

97

 

 

SALVIFodEnoho-IMEMW1

 

 

Figure 83: Ford 5.4 L V8 Engine Blowby Map - 0.6 End Gap Ring 1

 

 

MLVOFovdEn'ho-OJEMOQ1

 

 

Figure 84: Ford 5.4 L V8 Engine Blowby Map - 0.7 End Gap Ring 1

98

 

 

uLVIFqungun-umaqi

 

 

Figure 85: Ford 5.4 L V8 Engine Blowby Map - 0.8 End Gap Ring 1

 

 

MWFWW-O’EMWT

 

 

Figure 86: Ford 5.4 L V8 Engine Blowby Map - 0.9 End Gap Ring 1

 

10.4.3 Axial Width Variations

 

utvnrmawnawmr

 

 

Figure 87: Ford 5.4 L V8 Engine Blowby Map - 1.46 Axial Width Ring 1

 

 

SALVIFordEII'ho-t‘TAIHM‘I

 

 

Figure 88: Ford 5.4 L V8 Engine Blowby Map - 1.47 Axial Width Ring 1

100

 

 

SALV'FUI‘IEIIoho-LAIAXHMH

 

 

Figure 89: Ford 5.4 L V8 Engine Blowby Map - 1.48 Axial Width Ring 1

 

 

SALVIFOIIIEnflIo-lflhHM‘l

 

 

Figure 90: Ford 5.4 L V8 Engine Blowby Map - 1.49 Axial Width Ring 1

101

 

 

mnmmn-rammr

 

 

Figure 91: Ford 5.4 L V8 Engine Blowby Map - 1.50 Axial Width Ring 1

 

 

SALVIFOMEngho-LMAIHWHIH

 

 

Figure 92: Ford 5.4 L V8 Engine Blowby Map - 1.51 Axial Width Ring 1

102

 

 

unmm-iummr

 

 

 

 

Figure 93: Ford 5.4 L V8 Engine Blowby Map - 1.52 Axial Width Ring 1

 

10.4.4 Groove Height Variations

 

 

wwmm-iumwi

   

 

 

Figure 94: Ford 5.4 L V8 Engine Blowby Map - 1.46 Groove Height Ring 1

103

 

MWme-1MMM1

 

 

Figure 95: Ford 5.4 L V8 Engine Blowby Map - 1.47 Groove Height Ring 1

 

 

 

mvarmmm-iamwu

 

 

 

 

Figure 96: Ford 5.4 L V8 Engine Blowby Map - 1.48 Groove Height Ring 1

 

SALVIFordEnoho-‘IAOMW1

 

 

Figure 97: Ford 5.4 L V8 Engine Blowby Map - 1.49 Groove Height Ring 1

 

 

SALVIFon‘Ilngho-‘lflmw1

 

 

Figure 98: Ford 5.4 L V8 Engine Blowby Map - 1.50 Groove Height Ring 1

105

 

 

SALVIFOMEnfiho-LMGIOMNMH

 

 

Figure 99: Ford 5.4 L V8 Engine Blowby Map - 1.51 Groove Height Ring 1

 

 

MWFOMEngho-‘Inmudflhfl

 

 

 

 

Figure 100: Ford 5.4 L V8 Engine Blowby Map - 1.52 Groove Height Ring 1

 

SALVIFOIUEIIQMJMMW‘I

 

 

Figure 101: Ford 5.4 L V8 Engine Blowby Map — 1.54 Groove Height Ring 1

 

 

5.4LVIFordEngho-1550roovow1

 

 

 

 

Figure 102: Ford 5.4 L V8 Engine Blowby Map - 1.55 Groove Height Ring 1

107

10.4.5 Radial Thickness Variations

 

linFMEngh-ukldflmum1

 

 

Figure 103: Ford 5.4 L V8 Engine Blowby Map - 3.2 Radial Thickness Ring 1

 

 

SALVIFordEnoho-um'nim1

 

 

Figure 104: Ford 5.4 L V8 Engine Blowby Map - 3.3 Radial Thickness Ring 1

108

 

 

sniwmsm-ummumi

 

 

Figure 105: Ford 5.4 L V8 Engine Blowby Map - 3.4 Radial Thickness Ring 1

 

 

 

mwrwmm-ummmi

 

 

 

 

Figure 106: Ford 5.4 L V8 Engine Blowby Map - 3.5 Radial Thickness Ring 1

 

MLVIFudEnoln-ltmm1

 

 

Figure 107: Ford 5.4 L V8 Engine Blowby Map - 3.6 Radial Thickness Ring 1

 

 

uwrwm-ummi

 

 

 

 

Figure 108: Ford 5.4 L V8 Engine Blowby Map - 3.7 Radial Thickness Ring 1

110

 

MLVIFONI mm-unmmmi

 

 

Figure 109: Ford 5.4 L V8 Engine Blowby Map - 3.8 Radial Thickness Ring 1

 

 

wwrmmw-nnwmmr

 

 

 

 

Figure 110: Ford 5.4 L V8 Engine Blowby Map - 3.9 Radial Thickness Ring 1

111

 

 

SALVIFodEnoho-MMM1

 

 

 

Figure 111: Ford 5.4 L V8 Engine Blowby Map - 4.0 Radial Thickness Ring 1

10.4.6 Groove Diameter Variations

 

 

murmmm-ummomi

   

 

 

Figure 112: Ford 5.4 L V8 Engine Blowby Map - 82.00 Groove Diameter Ring 1

112

 

mnmm-ummr

 

 

Figure 113: Ford 5.4 L V8 Engine Blowby Map - 82.40 Groove Diameter Ring 1

 

 

unswm-mmmr

 

 

Figure 114: Ford 5.4 L V8 Engine Blowby Map - 82.60 Groove Diameter Ring 1

113

 

 

SALVIFadEngh-Mmml

 

 

Figure 115: Ford 5.4 L V8 Engine Blowby Map - 82.60 Groove Diameter Ring 1

 

 

wwmm-mmmr

 

 

Figure 116: Ford 5.4 L V8 Engine Blowby Map - 82.80 Groove Diameter Ring 1

114

 

 

mwrmm-Mmmi

 

 

Figure 117: Ford 5.4 L V8 Engine Blowby Map - 83.00 Groove Diameter Ring 1

 

 

mnmm-Mmmr

 

 

Figure 118: Ford 5.4 L V8 Engine Blowby Map - 83.20 Groove Diameter Ring 1

115

 

10.5 Ford 5.4 L V8 Engine Mini-Study
The following blowby maps were used to demonstrate the effect of the second

compression ring on the top ring. The end gap were varied in equal quantities for both the

top and second compression rings.

 

MWFWEMhu-OJEMGwlIZ

 

 

Figure 119: Ford 5.4 L V8 Engine Blowby Map - 0.3 End Gap Ring 1 & 2

 

MLVBFonIEngho-OAEMW1‘2

 

 

 

 

Figure 120: Ford 5.4 L V8 Engine Blowby Map - 0.4 End Gap Ring 1 & 2

116

 

sALvnFqungu-oxsnaonpuz

 

 

Figure 121: Ford 5.4 L V8 Engine Blowby Map - 0.4 End Gap Ring 1 & 2

 

 

MWMM-MEMGQ1‘2

 

 

Figure 122: Ford 5.4 L V8 Engine Blowby Map - 0.5 End Gap Ring 1 & 2

117

 

 

SALVUFOIIIEnnh-OJEMM1‘2

 

 

Figure 123: Ford 5.4 L V8 Engine Blowby Map - 0.6 End Gap Ring 1 & 2

 

 

SALVIFWEnuho-OJEMW1I2

 

 

Figure 124: Ford 5.4 L V8 Engine Blowby Map - 0.7 End Gap Ring 1 & 2

118

 

 

SAWFWEngho-OJEMGQ182

 

 

Figure 125: Ford 5.4 L V8 Engine Blowby Map - 0.8 End Gap Ring 1 & 2

 

 

SALVIFoMEngho-OJEndcmlfil

 

 

Figure 126: Ford 5.4 L V8 Engine Blowby Map - 0.9 End Gap Ring 1 & 2

119

 

lr1111111121111?(11111111111131)!

30