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PERPUSTAKAAN UTHM
' 3 0 0 0 0 0 0 2 1 0 3 5 8 7 *
DESIGN A CVT LUBRICANT TEST DEVICE
By
MO HI) AZWIR BIN AZLAN
Project Report Submitted to the Faculty of Engineering, Universiti Putra Malaysia, in Fulfillment of the Requirement for the Master in Innovation and
Engineering Design
November 2006
ABSTRACT
DESIGN A CVT LUBRICANT TEST DEVICE
By
MOHD AZWIR BIN AZLAN
NOVEMBER 2006
Chairman : Dr. Abdul Rahim Bin Abu Talib
Faculty : Engineering
T h e t e c h n o l o g y o f m e t a l p u s h i n g V - b e l t ( M P V B ) C o n t i n u o u s l y V a r i a b l e
T r a n s m i s s i o n ( C V T ) is n o w c o m m e r c i a l l y ava i l ab l e in t h e m a r k e t bu t to da te the
q u e s t i o n a b l e re l iab i l i t i es a n d l imi t ed t o r q u e capab i l i t i e s h a v e inh ib i t ed the i r g r o w t h .
Be l t s l ip is o n e o f t h e m a j o r lo s ses tha t c a u s e i n e f f i c i e n c y in C V T and l imi ted the
t r a n s f e r r e d t o r q u e f r o m t h e e n g i n e to the ty res . O n e o f the f ac to r s tha t b e l i e v e c a u s e
th i s bel t s l ip is b e c a u s e o f u n s t a b l e in oil l ub r i can t b e h a v i o u r e spec i a l l y d u e to
ope ra t e in h i g h t e m p e r a t u r e a n d p re s su re . T h e r e f o r e , th i s r epor t p r e s e n t s the w o r k
w h i c h h a s b e e n ca r r i ed ou t o n d e s i g n i n g a C V T L u b r i c a n t Tes t D e v i c e w h i c h c a p a b l e
to inves t iga t e t h e p h e n o m e n a o f f i l m co l l apse in a C V T m e c h a n i s m . M o d e r n des ign
c o n c e p t s a n d m e t h o d s h a v e b e e n app l i ed in d e s i g n i n g th i s d e v i c e w h e r e a f i ve p h a s e
d e s i g n m o d e l as p r o p o s e d b y E g g e r t h a s b e e n used . T h e five p h a s e d e s i g n s a re
f o r m u l a t i o n , c o n c e p t u a l des ign , c o n f i g u r a t i o n de s ign , p a r a m e t r i c d e s i g n and detai l
des ign . T h e d e v i c e is s i gn i f i can t b e c a u s e , h e n c e to s tudy and inves t iga te film
co l lapse , t h i s d e v i c e a l so c a p a b l e t o s tudy a n d inves t iga t e the o the r spec i f i c
p a r a m e t e r s w h i c h a f f e c t t h e t r a n s m i s s i o n e f f i c i e n c y s u c h as d i f f e r in con tac t ang le ,
con tac t a rea a n d mate r i a l u s e d .
ii
ABSTRAK
REKABENTUK ALAT UJIAN PELINCIR CVT
Oleh
.MOHI) AZWIR BIN AZLAN
NOVEMBER 2006
Pengerusi : Dr. Abdul Rahim Bin Abu Talib
Fakulti : Kejuruteraan
T e k n o l o g i T r a n s m i s i B e r u b a h B e r t e r u s a n ( C V T ) y a n g m e n g g u n a k a n
t a l i s awa t j e n i s l o g a m a tau d ikena l i s e b a g a i " M e t a l Pushing V-Belt" ( M P V B ) te lah
d i k o m e r s i a l k a n dan t e rdapa t di p a s a r a n m a s a k i n i , w a l a u b a g a i m a n a p u n k e r a g u a n dari
segi k e b o l e h a r a p a n d a n k e u p a y a a n d a y a k i l a s y a n g t e r h a d t e l ah m e n y e k a t
p e r t u m b u h a n d a n k e p e s a t a n n y a . K e g e l i n c i r a n t a l i s awa t ada l ah p e n y e b a b u t a m a
k e h i l a n g a n k e c e k a p a n p a d a C V T d a n s e t e r u s n y a m e n g h a d k a n p e n g h a n t a r a n d a y a
k i l a s dari en j in k e tayar . Sa l ah sa tu f a k t o r u t a m a y a n g m e n g a k i b a t k a n k e g e l i n c i r a n
t a l i s a w a t a d a l a h d i s e b a b k a n o l eh s i f a t m i n y a k pe l i nc i r y a n g t idak stabil t e r u t a m a n y a
k e t i k a be rope ra s i di d a l a m s u h u dan t e k a n a n y a n g t inggi . O l e h itu, l ap o ran ini
m e m b e n t a n g k a n k e i j a y a n g t e l ah d i j a l a n k a n di d a l a m m e r e k a b e n t u k alat u j i a n
pe l inc i r C V T di m a n a ia b o l e h d igunalcan u n t u k m e n y i a s a t f e n o m e n a k e g a g a l a n
f i l e m di d a l a m m e k a n i s m e C V T . A l a t ini t e lah d i r e k a b e n t u k d e n g a n m e n g g u n a k a n
k a e d a h d a n k o n s e p r e k a b e n t u k te rk in i y a n g t e l ah d i c a d a n g k a n o leh E g g e r t di m a n a
r e k a b e n t u k m o d e l l i m a f a s a t e l ah d i g u n a k a n . L i m a f a s a t e r sebu t ada lah , p e r s e d i a a n ,
r e k a b e n t u k k o n s e p , r e k a b e n t u k k o n f i g u r a s i , r e k a b e n t u k p a r a m e t r i k dan r e k a b e n t u k
te rper inc i . A l a t ini p e n t i n g ke rana , se la in d i g u n a k a n u n t u k m e m p e l a j a r i dan
m e n y i a s a t k e g a g a l a n f i l e m , alat ini j u g a b o l e h d i g u n a k a n u n t u k m e m p e l a j a r i dan
m e n y i a s a t p a r a m e t e r - p a r a m e t e r la in k h u s u s n y a y a n g m e m b e r i k e s a n t e r h a d a p
k e c e k a p a n t r a n s m i s i seper t i k e l a i n a n p a d a s u d u t s en tuhan , luas s e n t u h a n dan b a h a n
y a n g d i g u n a k a n .
iii
ACKNOWLEDGEMENTS
T h e a u t h o r is h i g h l y i n d e b t e d to Dr . A b d u l R a h i m A b u T a l i b f o r h i s g u i d a n c e
and con t r ibu t ion to c o m p l e t e th i s p ro j ec t . T h e a u t h o r h a s to a d m i t tha t , w i t h o u t h i s
g u i d a n c e a n d s u p p o r t th i s w o r k w i l l no t b e a s u c c e s s f u l one . A l s o no t to fo rge t ,
t h a n k s to t h o s e e x a m i n e r s D r . Zai r i l a n d Co l . T a r m i z i f o r the i r v a l u a b l e a d v i c e a n d
i n f o r m a t i o n .
T h e a u t h o r a p p r e c i a t e s h i g h l y t h e r o l e p l a y e d b y K o l e j Un ive r s i t i T e k n o l o g i
T u n H u s s i e n O n n ( K U i T T H O ) a n d J a b a t a n P e r k h i d m a t a n A w a m ( J P A ) fo r g r a n t i n g
s c h o l a r s h i p to a u t h o r t o c o n t i n u e h i s s t udy a n d s u p p o r t i n g th i s p ro j ec t .
T h e a u t h o r a l so a p p r e c i a t e s t h e he lp , a d v i c e a n d s u p p o r t g i v e n b y all h i s
f r i e n d s t h r o u g h o u t h i s s t udy in Un ive r s i t i P u t r a M a l a y s i a ( U P M ) .
Las t bu t n o t least , a u t h o r w o u l d l ike to a c k n o w l e d g e the ro le p l a y e d b y h i s
w i f e N o r H a s r i n a H a s n i , s o n N a j m i , d a u g h t e r N a z i h a h a n d o the r f a m i l y m e m b e r s ,
e spec i a l ly t o b o t h h i s p a r e n t s a n d p a r e n t in l a w s f o r the i r con t inua l s u p p o r t a n d
u n d e r s t a n d i n g .
i v
APPROVAL
I ce r t i fy tha t an E x a m i n a t i o n C o m m i t t e e h a s m e t o n 23 t h N o v e m b e r 2 0 0 6 t o c o n d u c t the fmal examination of Mohd Azwir bin Azlan on his Master in Innovation and Engineering Design project report entitled "Design a CVT Lubricant Test D e v i c e " in a c c o r d a n c e w i t h Un ive r s i t i P e r t a n i a n M a l a y s i a ( H i g h e r D e g r e e ) A c t 1980 a n d Un ive r s i t i P e r t a n i a n M a l a y s i a ( H i g h e r D e g r e e ) R e g u l a t i o n s 1981. T h e C o m m i t t e e r e c o m m e n d s that the c a n d i d a t e b e a w a r d e d the r e l e v a n t deg ree . M e m b e r s o f the E x a m i n a t i o n C o m m i t t e e a re as f o l l o w s :
Exair Col . M o h a m e d T a r m i z i B i n A h m a d A e r o s p a c e E n g i n e e r i n g D e p a r t m e n t Facu l ty o f E n g i n e e r i n g Un ive r s i t i Pu t ra M a l a y s i a
Examiner 2, PhD Zair i l A z h a r B i n Z a l u d i n A e r o s p a c e E n g i n e e r i n g D e p a r t m e n t Facu l ty o f E n g i n e e r i n g Unive r s i t i P u t r a M a l a y s i a
A b d u l R a h i m b in A b u T a l i b A e r o s p a c e E n g i n e e r i n g D e p a r t m e n t Facu l t y o f E n g i n e e r i n g Un ive r s i t i P u t r a M a l a y s i a
v
DECLARATION
I h e r e b y dec l a r e that the p ro jec t repor t is based on m y or iginal work excep t for q u o t a t i o n s and c i t a t ions w h i c h h a v e b e e n duly a c k n o w l e d g e d . 1 a l so dcc l a r c that il h a s no t b e e n p r e v i o u s l y o r c o n c u r r e n t l y s u b m i t t e d for any o the r d e g r e e at U P M or o t h e r ins t i tu t ions .
( ^ r . ; M O H D AZWIR BIN AZLAN
D a t e : 4 D i s e m b e r 2 0 0 6
TABLE OF CONTENTS
TITLE PAGE i
ABSTRACT ii
ABSTRAK iii
ACKNOWLEDGEMENTS iv
APPROVAL v
DECLARATION vi
TABLE OF CONTENTS vii
LIST OF TABLES x
LIST OF FIGURES xi
LIST OF APPENDICES xiv
CHAPTER 1 Introduction 1
1.1 I n t r o d u c t i o n 1
1.2 B a c k g r o u n d 3
1.3 P r o b l e m S t a t e m e n t 6
1.4 G e n e r a l O b j e c t i v e 8
1.5 Spec i f i c O b j e c t i v e s 8
v i i
1.6 S i g n i f i c a n c e o f D e s i g n
1.7 P r o j e c t R e p o r t O r g a n i z a t i o n
8
9
CHAPTER 2 Literature Review 10
2.1 O v e r v i e w 10
2 .2 C V T M e c h a n i s m 10
2 .2 .1 B a s i c C o m p o n e n t s 10
2 .2 .2 M e t a l P u s h i n g V - B e l t ( M P V B ) 11
2 .2 .3 C h a n g i n g S p e e d R a t i o 12
2 .2 .4 C V T P o w e r T r a n s f e r 14
2 .2 .5 C V T L o s s e s 17
2 .2 .6 C V T T e s t i n g 2 0
2 .3 L u b r i c a t i o n 21
2 .3 .1 L u b r i c a n t P r o p e r t i e s 22
2 .3 .2 V i s c o s i t y 23
2 .3 .3 V i s c o s i t y I n d e x (VI ) 26
2 .3 .4 V i s c o s i t y M e a s u r e m e n t M e t h o d 2 7
CHAPTER 3 Methodology 30
3.1 I n t r o d u c t i o n 30
3 .2 D e s i g n M e t h o d o l o g y 31
CHAPTER 4 Design Process 34
4.1 O v e r v i e w 3 4
4 .2 F o r m u l a t i n g N e e d 34
4 .3 C o n c e p t u a l D e s i g n 36
4 .4 C o n f i g u r a t i o n D e s i g n 4 0
4.4.1 C a s i n g M o d u l e 4 0
4 .4 .2 T r a n s f e r r i n g P o w e r M e c h a n i s m M o d u l e 41
4 .4 .3 C l a m p i n g F o r c e M e c h a n i s m M o d u l e 4 2
4 .4 .4 C o o l i n g S y s t e m M o d u l e 4 2
4 .4 .5 Ax ia l F o r c e T r a n s d u c e r 4 3
4 .4 .6 A r r a n g e m e n t o f C V T L u b r i c a n t Tes t D e v i c e 4 5
4.5 P a r a m e t r i c D e s i g n 4 6
4 .5 .1 D e v e l o p m e n t o f L u b r i c a n t T e s t D e v i c e ( L T D ) 4 6
4 .5 .1 .1 C a s i n g M o d u l e 4 7
4 .5 .1 .2 T r a n s f e r r i n g P o w e r M e c h a n i s m M o d u l e 4 8
c B e a r i n g Se l ec t i on 4 8
= D e t e r m i n a t i o n o f S h a f t S i ze 52
D D e t e r m i n a t i o n o f P o w e r T r a n s m i t t i n g P la t e s S ize 53
4 .5 .1 .3 C l a m p i n g F o r c e M e c h a n i s m M o d u l e 58
4 .5 .1 .4 A r r a n g e m e n t o f C V T L u b r i c a n t Tes t D e v i c e 59
4 .5 .2 Se lec t ion o f M a t e r i a l & M a n u f a c t u r i n g P r o c e s s e s 60
4 .5 .3 D e s i g n A n a l y s e s 65
4 .5 .3 .1 C o m p o n e n t W e i g h t E s t i m a t i o n 66
4 .5 .3 .2 C l a m p i n g F o r c e M e c h a n i s m A n a l y s i s 6 8
4 .5 .3 .3 C a s i n g A n a l y s i s 74
4 .6 De ta i l D e s i g n 84
4 .6 .1 L T D S p e c i f i c a t i o n 84
4 .6 .1 P r o d u c t i o n D r a w i n g 84
4 .7 D e s i g n R e v i e w 85
CHAPTER 5 Conclusion 88
5.1 C o n c l u s i o n 88
5 .2 R e c o m m e n d a t i o n 89
REFERENCES 92
APPENDICES 97
ix
LIST OF TABLES
TABLE TITLE PAGE
T a b l e 1 V a n D o o r n e m e t a l p u s h i n g V - b e l t s p r o d u c t spec i f i ca t i on . 12
T a b l e 2 L i s t o f t e s t i ng appa ra tu s . 21
T a b l e 3 E n g i n e e r i n g d e s i g n s p e c i f i c a t i o n f o r C V T lub r i can t tes t 35 dev ice .
T a b l e 4 M o r p h o l o g i c a l M a t r i x 37
T a b l e 5 A l t e r n a t i v e D e s i g n s C r e a t e d b y S y s t e m a t i c a l l y I n d e x i n g 38 t h e R o w s and C o l u m n s o f a M o r p h o l o g i c a l M a t r i x
T a b l e 6 C o n c e p t e v a l u a t i o n u s i n g w e i g h t e d r a t ing m e t h o d 3 9
T a b l e 7 Ki s t l e r indus t r i a l f o r c e s e n s o r s t e chn ica l da t a 4 5
T a b l e 8 S K F d e e p g r o o v e bal l bea r ing , s ing le r o w 4 9
T a b l e 9 S K F d e e p g r o o v e ba l l b e a r i n g 50
T a b l e 10 S K F n e e d l e ro l l e r t h rus t b e a r i n g 51
T a b l e 11 R e s u l t s f r o m ca lcu la t ion u s i n g M i c r o s o f t E x c e l 56
T a b l e 12 Se lec t ion o f m a t e r i a l s a n d m a n u f a c t u r i n g p r o c e s s e s 60
T a b l e 13 C o m p o n e n t s w e i g h t e s t i m a t i o n 6 6
T a b l e 14 C o e f f i c i e n t o f f r i c t i on f o r p o w e r s c r e w s 71
T a b l e 15 T o r q u e r e q u i r e d to r a i se and l o w e r i n g load 71
T a b l e 16 L o a d a n d w o r l d n g s t ress f o r m e t r i c c o a r s e t h r e a d 72
T a b l e 17 C a l c u l a t e d t o r q u e g e n e r a t e u s i n g h o o k s p a n n e r w r e n c h 73
T a b l e 18 C a s i n g ana lys i s s u m m a r i z e s 83
T a b l e 19 D e s i g n r e v i e w check l i s t 85
LIST OF FIGURES
FIGURE TITLE PAGE NO.
F i g u r e 1.1 T y p e s o f t r a n s m i s s i o n . 2
F i g u r e 1.2 E p i c y c l i c gea r t ra in . 2
F i g u r e 1.3 T r a n s m i s s i o n charac te r i s t i c . 4
F i g u r e 1.4(a) P u s h i n g me ta l V - b e l t C V T . 5
F i g u r e 1 .4(b) M e t a l d i sk t y p e C V T . 5
F i g u r e 2 .1 G e n e r a l c o n c e p t o f C V T . 11
F i g u r e 2 . 2 V a n D o o r n e m e t a l p u s h i n g V - b e l t . 11
F i g u r e 2 .3 T h e C V T s p e e d ra t io . 13
F i g u r e 2 .4 M e c h a n i s m o f C V T s h o w i n g t h e p o w e r t r a n s f e r r e d by 14 the e n g i n e to the o u t p u t C V T sha f t .
F i g u r e 2 .5 M P V B s h o w i n g s e g m e n t a n d b a n d s m o v i n g a r o u n d the 15 s e c o n d a r y pu l l ey .
F i g u r e 2 .6 C V T p o w e r t r a n s f e r d i a g r a m . 16
F i g u r e 2 .7 C o m p r e s s i o n and t e n s i o n in me ta l p u s h i n g V - b e l t in 17 s teady s ta te cond i t i on .
F i g u r e 2 .8 S c h e m a t i c d i a g r a m o f t h e e x p e r i m e n t a l tes t r ig. 2 0
F i g u r e 2 .9 C o n c e p t o f d y n a m i c v i scos i ty . 2 4
F i g u r e 2 .10 A S T M C h a r t f o r D i f f e r e n t T y p e s o f Lubr i ca t i on . 2 6
F i g u r e 3.1 D e s i g n m e t h o d o l o g y . 31
F i g u r e 4 .1 C V T lubr i can t tes t d e v i c e c o m p o n e n t d e c o m p o s i t i o n 36 d i a g r a m .
F i g u r e 4 .2 R o u g h l ayou t o f the C a s i n g m o d u l e . 4 0
F i g u r e 4 .3 R o u g h l ayou t o f the T r a n s f e r r i n g P o w e r M e c h a n i s m 41 m o d u l e .
x i
F i g u r e 4 . 4 R o u g h l ayou t o f t h e C l a m p i n g F o r c e M e c h a n i s m 4 2 m o d u l e .
F i g u r e 4 .5 R o u g h l a y o u t o f t h e C o o l i n g S y s t e m m o d u l e . 4 3
F i g u r e 4 . 6 Ki s t l e r m o d e l s 9 1 0 1 A , 9 1 0 2 A , 9 1 0 3 A , 9 1 0 4 A indus t r ia l 4 4 f o r c e senso r .
F i g u r e 4 .7 Ki s t l e r indus t r i a l f o r c e s e n s o r t e c h n i c a l d r a w i n g . 4 4
F i g u r e 4 .8 R o u g h g e o m e t r i c l a y o u t o f L u b r i c a n t Tes t D e v i c e 4 5 a rch i t ec tu re .
F i g u r e 4 . 9 De ta i l l ayou t o f C a s i n g m o d u l e . 4 7
F i g u r e 4 . 1 0 De ta i l l a y o u t o f T r a n s f e r r i n g P o w e r M e c h a n i s m m o d u l e . 4 8
F i g u r e 4 .11 S K F d e e p g r o o v e bal l b e a r i n g d i a g r a m 5 0
F i g u r e 4 . 1 2 O t h e r s u p p o r t c o m p o n e n t s f o r T r a n s f e r r i n g P o w e r 51 M e c h a n i s m m o d u l e .
F i g u r e 4 . 1 3 S K F A X K 8 0 1 0 5 & A X K 4 5 6 5 n e e d l e ro l le r th rus t 51 b e a r i n g d i a g r a m .
F i g u r e 4 .14 T h e bel t g e o m e t r y . 54
F i g u r e 4 . 1 5 T r a n s f e r r i n g P o w e r M e c h a n i s m m o d u l e e q u i p p e d w i t h 5 8 smal l , m e d i u m a n d la rge P T pla te .
F i g u r e 4 . 1 6 De ta i l l a y o u t o f the C l a m p i n g F o r c e M e c h a n i s m 58 m o d u l e .
F i g u r e 4 . 1 7 De ta i l g e o m e t r i c l a y o u t o f L u b r i c a n t Tes t D e v i c e 5 9 a rch i t ec tu re .
F i g u r e 4 . 1 8 P o r t i o n o f a C l a m p i n g M e c h a n i s m 2. 6 8
F i g u r e 4 . 1 9 F o r c e d i a g r a m on l o w e r i n g a n d l i f t ing the load . 69
F i g u r e 4 .20 T o r q u e g e n e r a t e u s i n g h o o k s p a n n e r w r e n c h . 72
F i g u r e 4 .21 G r a p h t o r q u e r e q u i r e d f o r a spec i f i c axia l f o r ce . 73
F i g u r e 4 . 2 2 O u t p u t a n d I n p u t L T D C a s i n g Pla te . 7 4
F i g u r e 4 .23 In s ide f a c e o f C a s i n g P l a t e a rea w h i c h co n t ac t ed by the 75 ax ia l f o r ce .
F i g u r e 4 . 2 4 B i g g e r p i c t u r e o f A O C sec tor . 75
F i g u r e 4 . 2 5 Res t r a in t s con t ro l b o x . 77
F i g u r e 4 . 2 6 L o a d con t ro l b o x . 78
F i g u r e 4 . 2 7 A p p l i e d l oad a n d res t ra in t s at O u t p u t L T D C a s i n g P la te . 78
F i g u r e 4 .28 S t re s ses in O u t p u t L T D C a s i n g P la te (axia l f o r c e = 79 2 0 , 0 0 0 N )
x i i
Figure 4 . 2 9 D e s i g n check for Output L T D Casing Plate (axial force 80 = 2 0 , 0 0 0 N )
Figure 4 . 3 0 Appl i ed force and restraints at Input L T D Casing Plate. 80
Figure 4 .31 Stresses in Input L T D Casing Plate (axial force = 81 2 0 , 0 0 0 N )
Figure 4 . 3 2 D e s i g n check for Input L T D Casing Plate (axial force = 81 2 0 , 0 0 0 N )
Figure 4 .33 Stresses in Horizontal Strengthening R o d (axial force = 82 2 0 , 0 0 0 N )
Figure 4 . 3 4 D e s i g n check for Horizontal Strengthening R o d (axial 82 force = 2 0 , 0 0 0 N )
Figure 5.1 Schemat ic diagram o f propose experimental facil it ies. 90
Figure 5 .2 Brookf ie ld A n a l o g Viscometer . 91
xiii
LIST OF APPENDICES
A P P E N D I X T I T L E P A G E
Append ix A Project 1 F l o w Chart 96
Append ix B Project 2 F l o w Chart 97
A p p e n d i x C Project Gantt Chart 98
Append ix D M P V B Detail Drawing 99
Append ix E Lytron Heat Exchanger I qq
Append ix F Kistler M o d e l s 9101 A, 9 1 0 2 A , 9 1 0 3 A , 9 1 0 4 A Industrial Force Sensors
Append ix G AISI 1141 Steel , hot rolled, 19-32 m m (0 .75 -1 .25 in) round
Append ix H Lubricant Test D e v i c e Detai l Drawing ] 05
xiv
CHAPTER 1 - INTRODUCTION
CHAPTER 1
INTRODUCTION
1.1 Introduction
A vehic le that is p o w e r e d by an internal combust ion engine wi l l be quite
imposs ib le to be driven smooth ly and comfortably without the aid o f a transmission
system. These by i tself expla ined the purpose and importance o f a transmission unit
in a vehic le . That is, they are the components that made it poss ib le to transfer the
p o w e r or torque from the engine to the driving w h e e l s (Tawi , 1997) . P o w e r is the
rate or speed at w h i c h work is performed, whi l e torque is turning or twist ing force.
Mult iple ratio gearboxes are necessary because the engine del ivers its m a x i m u m
power at certain speeds , or rpm (rotations per minute) . It is necessary to change the
gear ratio b e t w e e n the engine and the drive w h e e l s in order to use the same engine
rpm at different road speeds and this occurs inside the transmission.
Generally, transmission can be c lass i f ied into two categories, "steply" and
cont inuously variable transmission (CVT) . Both o f them can be further c lass i f ied as
manual and automatic transmiss ion as s h o w n in Figure 1.1. "Steply" transmissions
or gearboxes are those that use gears as their m e a n s to steply vary the gear ratios.
The manual steply gearboxes usually consist o f s ix sets o f gear train. N a m e l y first,
second, third, forth, f i f th and reverse gears. The forward gears are usually o f hel ical
type because o f its smooth and quiet performance, w h i l e the reverse gears are o f spur
type, w h i c h is a bit no isy (drivers should be able to recognise this) but can be easi ly
d o g g e d wi th its mesh ing spur gear v ia an idler spur gear, hence el iminate the use o f
1
CHAPTER / - f!\TRODUCTIO.\
synchromesh as in the forward gears. These types of gearboxes are usually manual
in nature, i.e. the drivers select the required gear ratios themselves through gear
linkages.
StepJy Transmission
Transm i ssion
Continuously Variable Transmission
Figure 1.1 : Types of Transmission
Currently for automatic steply gearboxes, most cars use epicyclic gear train
and they are hydraulically controlled. Epicyclic gear train (Figure 1.2) consists of
sun, planet and ring gears. They can be of spur type (noisier but cheaper) or helical
type (quieter, smoother but a bit expensive). The advantage of epicyclic gear train is
that gear ratio change can be done easily by just stopping either the sun, planet or
ring gear to change gear (two forwards and one reverse).
Ring gear
Sun gear
Planet gears
Figure 1.2: Epicyclic Gear Train
2
CHAPTER I - INTRODUCTION
Other categories o f transmiss ion are k n o w n as C V T . C V T also can be further
c lass i f ied as manual , automatic or combinat ion o f these. More detail about C V T wi l l
be explained in the background. N o w a d a y s , w e can see many car manufacturer is
start to get invo lve into the cont inuously variable types due to the promis ing o f their
performance. M a n y w e l l - k n o w n car manufacturers l ike Audi , General Motor, Honda
and N i s s a n have been produced their o w n product.
1.2 Background
Transmiss ion deve lopment started wi th very s imple des igns o f a manual gear
boxes . Then, an automatic step gear transmiss ion w a s introduced due to demand for
more comfort . E v e n though the control o f automatic transmission getting better, they
still have jerking during changing gear ratio causes uncomfortable drive. The third
generation o f gear b o x w a s cal led cont inuous variable transmission (CVT) .
Brace ( 1 9 9 2 ) has studied in comparison b e t w e e n manual, automatic and
cont inuously variable transmission. H e conc luded in the graph as s h o w n in Figure
1.3, w h i c h he had conc luded each o f transmiss ion has advantages and disadvantages.
These advantages and disadvantages are set in scale one to f i ve rating w h i c h one
represent unsatisfactory and f i ve represent very good. Manual transmission has
disadvantages in the performance o f driving, but this disadvantage can be o v e r c o m e
by both automatic and C V T . Size , cost, mass , and fun o f driving b e c o m e less value
in both automatic and C V T .
The C V T concept a l l o w s the engine speed to be operated independently o f
the veh ic le speed and therefore the engine can a lways be operated in its mos t fuel-
ef f ic ient operating point. Therefore C V T s have a great potential to of fer both fuel
consumpt ion and lower output o f harmful exhaust emiss ions , w h i c h has been
conf irmed by different research projects. Torotrak D e v e l o p m e n t Ltd. c la imed ( 2 0 0 6 )
2 0 % less fuel consumpt ion for their C V T transmission than wi th a conventional
automatic gearbox along wi th a reduction in harmful emiss ions . A simulation study
by Kriegler ( 1 9 9 7 ) o f A V L compares different C V T concepts wi th a manual
3
(JliArihK I - IN 1 KUUUl. UU1S
transmission for gasol ine and diesel engines and s h o w up to 10% less fuel
consumption for gasol ine engines and up to 19% for diesel engines.
Sub-system Ef f ic iency
Size
W e l l d r i v e n
Fuel Consumpt ion
Sub-system Ef f ic iency
Size
\ / / A g g r e s s i v e d r i v i r
Mass
Performance
Easy o f D r i v i ng
Cost
V "" I ^ / \ 1 / V J \ i | /
Fuel Consumpt ion
,.,.» 5 speed +
. j s ss^ Perfonnance
\
/ \ Fun o f D r i v i n g Shi f t Qual i ty
Mass i ' -
/ V Fun o f D r i v i ng Shif t Qual i ty
Easy o f D r i v i ng
Sub-system Ef f ic iency
Size
\ Fuel Consumpt ion
H i g h e f f i c i e n c y C V T / 1 V T w i t h
\ i n t eg ra ted p o w e r t r a i n c o n t r o l
Cost
Mass
P Performance
j H ; i : h ( ' V i
yy y Easv of D r i v i ng
Fun o f D r i v i ng Shif t Qual i ty
Figure 1.3: Transmission Characteristic. (Brace, 1992)
The first commercial ly available belt type C V T w a s introduced in 1958 and
w a s based on rubber V belt (Birch, 2000) . Meanwhi le the C V T principle has
evaluated to a fully electronic controller transmission system, based on a metal belt,
and is capable to be adapted to engines o f almost size.
A number o f studies have been conducted on the C V T because it is regarded
as an ideal transmission for internal combustion engine vehicles . C V T tended to be
regarded as just a transmission without shift shock and this causes more comfort
comparing with the conventional automatic transmission. C V T eliminated the two
4
CHAPTER I - INTRODUCTION
major problem o f the automatic transmission which is shift shock and time lag
resulting in better fuel consumption (Kevin, 2000) .
C V T used the entire range o f ratios between low and high gears compare to a
conventional automatic transmission, which shifts among up to five gear ratios. It
achieves better fuel e c o n o m y and drivability by constantly changing ratios to keep
the engine running in its-most efficient rpm range based on driver demands.
C V T is beyond all doubt the theoretically optimum gearbox for automotive
applications. There are four basic concepts on which extensive modern-day C V T
developments have been or are currently based that are belt drive CVT, hydrostatic
pump and motor combinations CVT, friction or traction drive C V T and lastly
variable stroke C V T (Gott, 1991). Currently there are only two types o f C V T
commercial ly success to the market that are belt drive C V T and traction drive C V T
as shown in Figure 1.4(a) and 1.4(b). Both types have already powering more than
mil l ion cars including Fiat, Ford, Nissan, Honda, Subaru, Toyota, General Motor,
Audi and Volvo .
Figure 1.4(a): Pushing Metal V-belt CVT Figure 1.4(b): Metal Disk type CVT
(Transmission: CVT (Continuous Variable Transmission). Mark, 1998)
Early belt drive C V T used simple rubber band and cone system as low power
industrial drives and light-duty vehicle applications such as snowmobi les , go-karts
and all-terrain vehicle. In 1958 D A F (now V o l v o ) introduced a small passenger car
equipped with a rubber belt CVT. However , the maximum torque, which can be
transmitted, is limited by the strength o f the belt and the coeff ic ient o f friction
between the belt and the pulley (Gott, 1991). Then, a new belts which its power-
Gear ratio of EXTROID CVT Ratio change
/ Gear Output radius, ro I ' ratio Input radius, ri
Input f rom " r ' the engine i r Output to the tires
Input disc r - ] — | Output disc
Power rol ler
5
CHAPTER I - INTRODUCTION
rating can n o w meet the requirement o f automot ive application has b e e n introduced
in the market s ince late 80s . It is cal led as Metal Pushing V - B e l t ( M P V B ) , w h i c h
deve lops by V a n D o o r n e from V a n D o o r n e ' s Transmiss ie (a company spun out o f
D A F - v a n D o o r n e ' s A u t o m o b i l e Factory). This belt consists o f a large number o f flat
segments , w h i c h are held together by two packs o f steel bands, each pack containing
eight to ten bands for f lexibi l i ty. Then this belt has been put into production by Ford,
Subaru and Fiat. Borg-Warner and Fiat had formed a consort ium wi th van Doorne in
the m i d ' 7 0 s to deve lop a C V T based o n the van Doorne belt (Gott, 1991) . Borg-
Warner later removed them from the consort ium to pursue their o w n interests. They
have deve loped a similar variable c o n e pul ley transmiss ion concept using a chain,
w h i c h produced, by Suzuki in early 1990s . Another approach is by PIV-Reimers
chain-type C V T that is reportedly be ing examined by Ford, V o l v o and ZF (Gott,
1991) .
In 1999 , N i s s a n w a s the first automaker to introduce a C V T for the front-
transverse drivel ine in conjunct ion with an engine having greater than 1 0 0 - k W (135-
hp) output. The Primera features engine torque o f about 190 N . m . One o f the latest
C V T s is the CFT 23 deve loped by ZF, w h i c h is des igned for engine torque up to 2 5 0
N . m and features an overall gear-ratio span o f 5.8. In 2 0 0 0 , Audi introduced a C V T
for a front-longitudinal drivel ine in connect ion wi th a s ix-cyl inder 2 .8 -L engine. The
V L 3 0 0 w a s the first C V T for h igh torque appl icat ions-280 N . m . It has w e t clutch
and chain and an overall gear-ratio span o f 6 .05 (Birch, 2 0 0 0 ) .
1.3 Problem Statement
C V T have been used in automobi les for decades; h o w e v e r l imited torque
capabilit ies and quest ionable reliability have inhibited their growth. Today ongo ing
C V T research has led to ever more robust transmissions and thus ever more diverse
automotive applications. The trend toward greater performance in small cars and the
deve lopment o f higher-torque diesel engines have sharpened the des ign focus on
overcoming the C V T ' s torque limitations.
6
CHAPTER I - INTRODUCTION
The efficiency of a vehicle transmission system is an important factor in the
overall efficiency of any vehicle. It is important to understand where the
inefficiencies lie within a transmissions design in term of emissions and fuel
consumption because the increased environmental constraints which today vehicle
much reach.
CVT should allow better matching of the engine operating conditions to the
variable driving conditions that may be experienced by effecting having an infinite
number of gear ratios. However, the reduced fuel consumption and emissions
predicted for CVT have not been realized by production cars. Comparison fuel
consumption between CVT and equivalent fixed ratio has resulted they have been at
best equal and in most cases considerably lower. This can be concluded that existing
CVT system have a lower efficiency that their fixed ratio counterparts although the
control strategy for reduced fuel consumption is well founded. This inefficiency has
been linked to a number of possible inherent parasitic losses associated with pushing
V-belt CVT, namely torque losses within the belt mechanism itself, belt slip and
hydraulic control system pumping losses. Belt slip is one of the major losses that
caused inefficiency in CVT. There are two reasons why this belt slip happens. The
first factor is caused by insufficient clamping force that used to squeeze the belt for
transferring torque from input shaft to output shaft. Another factor is lubricant film
collapse due to operating temperature increase.
Lubricants used in CVT have a large number of performance characteristics
to satisfy, such as lubrication, heat transfer, pump ability and traction transfer. Belt
drive CVT and traction drive CVT use special lubricant formulations which added
with more traction additives to increase the torque transfer capability. These traction
additives increase the coefficients of friction between other surfaces in relative
motion to each other and avoid slip between belt and pulley, but too many will make
the oil become condense and cause the transmission need more power from engine to
rotate hence decrease its efficiency. Slip must be minimized to protect the CVT
mechanism from wear. However, unstable in oil lubricant behaviour, especially when
it viscosity change due to operate in extreme condition such as in high temperature
and high pressure, will effect the transmission efficiency.
7
CHAPTER I - INTRODUCTION
Hence, this study is one of the pioneer works in UPM towards acquiring the
knowledge and technology of CVT system. A design for basic clutch-like CVT
mechanism and experimental facilities set-up are proposed, to study the phenomena
of lubricant film collapse between the power transmitting plates. This film collapse is
crucial as a result of slip between the plates, affecting the overall transmission
efficiency.
1.4 General Objective : To design a CVT lubricant test device that
capable to investigate the phenomena of film
collapse in a CVT mechanism.
1.5 Specific Objectives :
i. To conduct literature study based on the Van
Doorne Metal Pushing V-Belt CVT.
ii. To produce detail design of a CVT lubricant
test device suitable for small size car, (less
than 1 litre engine).
iii. To propose an experimental facility for film
collapse investigation in a CVT mechanism.
1.6 Significance of Design
As stated previously, existing CVT are usually limited in their performance.
Most CVT have drawbacks such as limited range of variability, limited power
handling capabilities and efficiency. All these factors have encouraged the author to
rise to the challenge of designing a lubricant test devise in a CVT mechanism. The
main purpose is to investigate the phenomena of film collapse in actual condition
which the author believes it is the main reason that affect the transmission efficiency.
Its also hope that by using this devise, other specific parameters that are related to the
power transferred such as belt-pulley contact angle, belt-pulley contact area, material
used, clamping force needed and other parameters can also be investigate.
8
