Muroran-IT Academic Resources Archive Title Author(s) Citation Issue Date URL Behavior of Fuel Liquid-Film Flow in Intake Manifold of two Stroke Cycle Engine Hayashi, Shigenobu; Sawa, Norihiro 室蘭工業大学研究報告.理工編 Vol.9 No.1, pp.277-295, 1976 1976-12-18 http://hdl.handle.net/10258/3651 Rights Type Journal Article See also Muroran-IT Academic Resources Archive Copyright Policy Muroran Institute of Technology BEHAVIOROFFUELLIQUID-FIL 乱 1 :FLOWININTAKE . MANIFOLDOFTWOSTROKECYCLEENGINE ShigenobuHayashiandNorihiroSawa* A b s t r u c t h em o s to ff u e lf e e df r o mac a r b u r e t t o rf l o w sa l o n gi n s i d ew a l lo fi n t a k em a n i f u l d l nac a r b u r e t t o re n g i n e,t h i c hs h o w sa na s p e c to fv e r yc o m p l e x .T h e r e f o r e,i ts e e m st h a tt h eb e h a v i o ro f i nt h ef r o mo fl i q u i d,w np a r t i c u l a r,t h ec y c l e v a r i a t i o no fe f f e c t i v em i x t u r 巴s t r e n g t h l i q u i d f i l mf l o wh a sar e m a r k a b l ei n f l u e n c eo n,i h ef u e ld i s t r i b u t i o ni nam u l t i c y l i n d e re n g i n ea n da l s ot h em i x t u r ef o r m a t i o nd u r i n ga i nt h ec y l i n d e r,t t r a n s i t i o n a lr u n n i n g . A c c o r d i n g l y,t o巴x a m i n ei nd e t a i lt h eb e h a v i o ro ff u 巴1l i q u i d f i l m,t h ea u t h o r sh a v et r i e dt om e a s u r e d i r e c t l yt h ea m o u n to fl i q u i d f i l mb ym e a n so fas e p a r a t o ri n s e r t e di ni n t a k em a n i f o l da n da tt h es a m et i m e t or e c o r dt h ei n s t a n t a n e o u sb e h a v i o ra n dt h ed i s t r i b u t i o no fi t st h i c k n e s sb yt h ec h a n g ei ne l e c t r i cc o n d u c t i v i t y 巴e x p e r i m e n t sa sm e n t i o n e da b o v e T h i sp a p e rp r e s e n t st h er e s u l t so b t a i n e df r o mt h 目 1 . Introduction I nag a s o l i n ee n g i n e,t h emosto ff u e ls u p p l i e dfromac a r b u r e t t o rd o e sn o tv a p o r i z eand f l o w sa l o n gi n s i d e w a l lo fi n t a k ep i p et oane n g i n ec y l i n d e ra sl i q u i d . Noto n l yt h ef l o w q u a n t i t yo ft h i sl i q u i d f u e li sr e m a r k a b l ei n f l u e n c e dbyt h edimensiono fi n t a k ep i p esystem and t h er u n n i n gc o n d i t i o nb u ta l s ot h ef l o ws t a t e shows an a s p e c to fv e r y complexY) T h e r e f o r e,i tseemst h a tt h eb e h a v i o ro ff u e l l i q u i d f i l mf l o wh a sar e m a r k a b l ei n f l u e n c eon, i np a r t i c u l a r,t h ec y c l ev a r i a t i o no fe f f e c t i v emixtures t r e n g t hi nt h ec y l i n d e r,t h ef u e ld i s t r i b u t i o ni nt h em u l t i c y l i n d e re n g i n e under a s t a t i o n a r yo p e r a t i o n anda l s ot h e mixture f o r m a t i o nd u r i n gat r a n s i t i o n a lr u n n i n g ( 2 )叶 6) A c c o r d i n g l y,t oexaminei nd e t a i !t h eb e h a v i o r h ef u e ld i s t r i b u t i o nandt h ef u e ls u p p l i e ds t a t e under a t r a n s i t i o n a l o fl i q u i d f i l mf l o w,t h ea u t h o r shavet r i e dt omeasured i r e c t l yt h e r u n n i n ga sw e l la sas t a t i o n a r yo p e r a t i o n,t amounto ff u e l l i q u i d f i l mf l o wbymeanso ft h es e p a r a t o ri n s e r t e di nt h ei n t a k em a n i f o l do f t h es m a l l s i z e dtwo s t r o k ec y c l ee n g i n eandt or e c o r dt h ei n s t a n t a n e o u sb e h a v i o randd i s t r i b u t i o no ff u e ll i q u i d f i l mt h i c k n e s s from t h e change i ne l e c t r i cc o n d u c t i v i t y . Such e x p e r i m e n t a lr e s u l t sw i l ld i s c r i b e di nt h ef o l l o w i n g 2 . ExperimentalApparatusandMethod 2 . 1 ExperimentonBehavioro fFuelLiquid-FilmFlow Ag e n e r a ll a y o u to fexpermentala p p a r a t u sf o rt h eb e h a v i o ri sshowni nF i g .1 . I nt h i s f i g u r e,ani n t a k ep i p esystemusedi st r a n s p a r e n t,s ot h a ti ti sp o s s i b l et oo b s e r v et h eb e h a v i o r o ff u e l l i q u i d f i l mf l o wandt ot a k et h ephotographo ft h e s e . Thea u t h o r susedat e s te n g i n e E 1 2 5i . e .ac r a n k c a s ecompressedtwos t r o k ec y c l ee n g i n ef o rmotorb i c y c l e,whosedimen s i o n sa r ed i s c r i b e di nTable1 . Moreover,a l lt h et e s t sa r ec a r r i e do u ti nt h emotorings t a t e 本 P r o f .a tt h el b a r a g iU n i v ( 2 7 7 ) 2 7 8 S h i g e n o b uH a y a s h iandN o r i h i r oSawa Table1 Dimensiono ft e s tengine 巴t e ro f D i a m i n t a k ep i p e Typeo fi n l e t v a l v e 1 2 3 c c 2 1訂1江1 P i s t o n 3 5 9 c c 36mm v a l v e T e s te n g i n e S t r o k ev o l u m e E125 E-360 F i g .1 G e n e r a ll a y o u to f e x p e r m e n t a l appa r a t u s( E 1 2 5 ) 巴 C y c .:C y c l o n C a b . C a r b u r e t t o r p :E l e c t r o d e t :Thermocouple S e p .:S e p a r a t o r( F i g .@) l n d .:P r e s s u r ei n d i c a t o r ー Fig.2 G e n r a l l a y o u to fe x p e r i m e n t a la p p a r a t u s( E 3 6 0 ) ①T e s te n g i n e ②V a r i a b l es p e e dmotor ③ l n l e t p l p e ④⑤E l e c t r o d ef o rm e a s u r i n gl i q u i d f i l m t h i c k n e s s ⑥ P r e s s u r e i n d i c a t o r ⑦B u r e t t e ⑧ TDCm arker⑨ E x h a u s tt h r o t t l ev a l v e⑬ C a r b u r e t t o r⑪l n d e xo fc a r b u r e t t o r叩e n n i n 耳⑫l n s t a n t a n e o u sl a m i n a rf l o wmeter ⑬ Manometerf o r l a m i n a rf l o wm e t e r⑬ F l o a tchamber⑮ F u e lf l o w u e lt a n k ⑪ Manometerf o rm e a s u r i n g m e t e r ⑬F ① 耐tpressure L 2 2 : 三① E υ 工 94 F i g .3 D i m e n s i o no fi n t a k em呂n i f o l d EP:P o s i t i o no fe l e c t r o d e 0 . 5 い け作、『別 F i g .4 C a l i b r a t i o nc u r v e( C o n c e n t r a t i o no fs o l u t i o n ) c i l l o g r m H :Amplitudeo n口s h:T h i c k n e s s( o rd e p t h )o fl i q u i d f i l m ( 2 7 8 ) BEHAVIOR OF FUELLIQUID-FILM FLOW IN INTAKE MANIFOLD OF TWOSTROKECYCLEENGINE 2 7 9 T a b l e2 C h a r a c t o ro fu s e dr l e t h a n o l G α /G / ( G α /G T a b l e3 C a l c u l a t e dv a l u eo f[ f] f) C a r b u r 巴t t o ro p n i n g( 8 ) M i x t u r er a t i o(Ga/Gf) 3 0 9 0。 1 . 2 7 7 0.890 1 . 1 9 6 1.004 0 andt h e n as e p a r a t o randtwoc y c l o n e sweree x s e r t e d,i fn e c e s s a r yf o rt h ep u r p o s eo fe x e t h a n o l( s e e p e r i m e n t . F o rt h emeasuremento fi n s t a n t a n e o u st h i c k n e s so ff u e l l i q u i d f i l m,m ,l i nwhiche x t r e m e l ys m a l lq u a n t i t yo fCH3COONa T a b l e2 )i n s t e a do fg a s o l i n ei su s e da sf u e i sd i s s o l v e dt oi n c r e a s et h ee l e c t r i cc o n d u c t i v i t yandt h ef u e ll i q u i d f i l mt h i c k n e s si si n d i r e c t l yd e t e r m i n e dfromt h echangei ni t se l e c t r i cc o n d u c t i v i t yowingt ot h et h i c k n e s so f h emanye l e c t r o d e sweres e t t e dont h ep i p ew a l li nt h er e s p e c t i v e s o l u t i o n . T h e r e f o r e,t p o s i t i o n s( s e eF i g .1 )t omeasuret h ec i r c u m f e r e n t i a landl o n g i t u d i n a ld i s t r i b u t i o no fl i q u i d h i c k n e s s( h )o ff u e l l i q u i d f i l ma r es i m u l t a n e o u s l y f i l mt h i c k n e s s . Thef l o wr a t e(Gfl) andt measuredo v e rawider a n g eo ft h ei n t a k ep i p el e n g t h( L s ) ,t h ef l o wr a t eo fs u p p l i e df u e l(Gf), t h eo p e n i n go fc a r b u r e t t o r( C )andt h ee n g i n es p e e d( N )e t c . . i s t r i b u t i o no fF u e lL i q u i d F i l mFlow 2 . 2 ExperimentonD Ag e n e r a ll a y o u to fe x p e r i m e n t a la p p a r a t u sf o rt h ed i s t r i b u t i o ni sshowni nF i g .2 . A t e s te n g i n ei sac r a n k c a s e c o m p r e s s e dtwos t r o k ec y c l ee n g i n ew i t htwoc y l i n d e rE 3 6 0, whosemaind i m e n s i o n sa r ed i s c r i b e di nT a b l e1anda l lt h et e s t sc a r r i e do u ti nt h em o t o r i n g h ee x c e p t i o no fb r a n c hp a r ti st r a n s p a r e n ts ot h a ti ti s s t a t e . Ani n t a k ep i p esystem③ wtht p o s s i b l et oo b s e r v et h es t a t eo ff u e l l i q u i d f i l mt r a v e l i n gfromac a r b u r e t t o rt ot h ei n d i v i d u a l omeasuret h e c y l i n d e rv i aani n t a k em a n i f o l dandt ot a k et h ep h o t o g r a p ho ft h e s e .B e s i d e,t h emanye l e c t r o d e sweres e t t e dont h e i n s t a n t a n e o u st h i c k n e s so ff u e ll i q u i d f i l mf l o w,t i n s i d e w a l li nf r o n tandi nr e a r④ ⑤ o fb r a n c hp a r to fi n t a k em a n i f o l dandt h a ttwos e p a r a t o r s ⑦w erei n s e r t e di nt h ec y l i n d e rs i d et omeasured i r e c t l yi t sf l o wq u a n t i t y . Thep r i n c i p l e h o u g hr e g u l a r d i m e n s i o nands h a p eo fi n t a k em a n i f o l da r eshown i nF i g .3 . F u r t h e r, t g a s o l i n ewasm a i n l yu s e dt oexamine t h ee f f e c t so fv a r i o u sf a c t o r s ont h eq u a n t i t a t i v e h eo t h e rhand,f o re x p e r i m e n tp e r t a i n i n gt ot h e d i s t r i b u t i o no ff u e ll i q u i d f i l mf l o w,ont e t h a n o li n s t e a do fg a s o l i n ewase m p l o i e da sf u e l,i n b e h a v i o ro ff u e l l i q u i d f i l mt h i c k n e s s,m f0.1-1 volume percentage~ I nt h e wide r a n g eo fv a r i o u s whichc o n t a i n s CH3COONao h a ti s,t h ec a r b u r e t t o ro p e n i n g(8)i sfrom3 0t o9 0( f u l lo p e n ),t h e o p e r a t i n gc o n d i t i o n s,t fi n t a k em a n i f o l di s4 ど , t h ea d d i t i o n a lp i p el e n g t h( L s )i sO-l O Ocm i n c l i n a t e da n g l e(β)o andt h em i x t u r er a t i o(Ga/Gf) i s5-20e t c .,wemeasuredb r e a t h i n ga i rc a p a c i t y(Ga ) ,t h e amounto fs u p p l i e df u e l(Gf),t h eq u a n t i t yo ff u e ll i q u i d f i l mf l o w i n gt oi n d i v i d u a lc y l i n d e r (Glb,GlC) a ndi t st e m p e r a t u r e( t )a f t e rt h ee n g i n ec o n d i t i o nr e a c h e dt oas t a t i o n a r ys t a t ei n 0 0 _ ( 2 7 9 ) S h i g e n o b uH a y a s h ia n dN o r i h i r oSawa 280 o examine t h ep r i n c i p l ec a u s eo fm a l d i s t r i b u t i o n,t h e m o t o r i n go p e r a t i o n . Moreover,t h ep r e s c i r c u m f e r e n t i a ld i s t r i b u t i o no ff u e l l i q u i d . f i l mt h i c l α l e s si ne a c hp o s i t i o n④,⑤ andt s u r ev a r i a t i o ni nb o t hc r a n k c a s e⑥ and i n t a k ep i p e⑥ a r es i m u l t a n e o u s l yr e c o r d e d on a e l e c t r o m a g n e t i co s c i l l o g r a m . ‘ 2 . 3 Measuremento fF u e lL i q u i d F i l mThickness swass t a t e dp r e v i o u s l y,wehaver e p e a t e dmanyp r e l i B e f o r ea d o p t i n gt h emethod,a minarye x p e r i m e n t so nt h es e l e c t i o no fe l e c t r o d e ' sm a t e r i a lando fs u b s t a n c et ob ed i s s o l v e d sm a i n l ya f f e c t e dbyi t sv i s c o s i t y andt h e nt h ec o n d i t i o no ff u e l l i q u i d . f i l mf o r m a t i o n,whichi i n c et h ee l e c t r i cc o n d u c t i v i t yo ff u e l( i . e .s o l u t i o n )c a n ands u r f a c et e n t i o ne t c . . I ng e n e r a l,s h et e m p e r a t u r ed e c r e a s eo ft h es o l u t i o nduet oe v a p o r a t i o n b echangedbyi t sc o n c e n t r a t i o n,t ti s andt h es o u r c ev o l t a g ef o rm e a s u r i n gc i r c u i te t c .a su n d e r s t o o dfromF i g .4andF i g .5,i n e c e s s a r yt od e t e r m i n et h ee x p e r i m e n t a lc o n d i t i o n s . T h e r e f o r,wea d o p t e dt h ef o U o w i n g c o n d i t i o n sfromt h ee x p e r i m e n t a lr e s u l t s . E l e c t r o d e ' sm a t e r i a l :p l a t i n u mo rs t a i n l e s ss t e e l t( s e eF i g .4( 0 ) E l e c t r o d e ' sd i a m e t e r :2mmc C a r b . b 31 ﹁ 0hm H a N= 600rpm m =9 . 6 , Y .= 2 . 1m/s oh 05n 3t CHCOONa ' 0 。 , 0 . 1 附 ε1 I l 20V2s ' =1 工 2 ' 5V/ , /1 ; 4 2 1 , I / / h mm 2 ノグ /1 噌 噂E h mm 0 . 5 hm m F i g .5 C a l i b r a t i o nc u r v 巴 ( E f f e c t so fs o u r c ev o l t a g ea n df u e l t e m p e r e t u r 巴 ) F i g .6 C i r c u m f e r e n t i a ld i s t r i b u t i o no ff u e l l i q u i d f i l mt h i c k n e s sf o re n g i n es p e e d (E125) ( 2 8 0 ) BEHAVIOROFFUELLIQUID-FILMFLOWININTAKEMANIFOLD OF TWOSTROKECYCLEENGINE D i s t a n c ebetweene l e c t r o d e s S o u r c ev o l t a g e F u e l D i s s o l v e ds u b s t a n c e 281 :5mm( s e eF i g .4( t ) :5V ( 5 0H z ) wooda l c o h o l v o l u m er a t i o0.1-1%) CH3COONa( 3 . ExperimentalR e s u l t sandC o n s i d e r a t i o n s . FlowRateandThicknesso fF u e lL i q u i d F i l munderS t a t i o n a r yOperation 3 .1 .1 IntakeP i p eLength( L s ) 3 .1 Thed i s t r i b u t i o no ff u e ll i q u i d f i l mt h i c k n e s s( h )i nt h el o n g i t u d i n a ld i r e c t i o no fi n t a k e h ea d h e s i o no f p i p ed e p e n d so nt h es p r a y ' sc o n d i t i o no ff u e lf l o w i n go u tfromac a r b u r e t t o r,t h ee v a p o r a t i o n from f u e ll i q u i d f i l mf l o w,t h e f l o a t i n gf u e ld r o p l e tt ot h ep i p ew a l l,t g r a v i t a t i o n a lf o r c ee t c .,s ot h a tt h ep h e n o - 0.5 menoni se x t r e m e l yc o m p l i c a t e dandc a nb e h changedbyn o to n l yt h ea t o m o s p h e r l cs t a t e mm b u ta l s ot h ed r i v i n gc o n d i t i o no fe n g i n e,t h a t h em i x t u r er a t i o( m ), t h eo p e n i n go f 0 i s, t c a r b u r e t t o r( C )andt h ee n g i n es p e e d( N )e t c . 0.5 h eau 伽 F o rt h i sr e a s o n,t a b l et odrawany s y s t e m a t i cc o n c l u s i o n,b u t t h eo u t l i n eo fr e s u l t so b t a i n e dfrom F i g .6 0 andF i g .7a r ea sf o l l o w s . 0 . 5 ① Somep a r to ff u e lf l o w e do u tfroma h c a r b u r e t t o ra t t a c h e st ot h ep i p ew a l li nf r o n t mm o ft h ee l e c t r o d e a( i . e .1= 6 5mm)andt h a t f l o w sa l o n gt h ei n s i d ew a l li nt h e form o f 0 5 l i q u i d . I nt h ec a s eo fl o we n g i n es p e e d( e . g . 0. N=600r p r f u e ll i q u i df l o wi sd r o p l i k eb u tt h ed r o p s g a t h e rw i t ht h e i ra d v a n c et o w a r d st h ee n g i n e c o n s e q u e n t l ys o c a l l e df u e ll i q u i d f i l mf l o wi s 1 f o r m e d . Ofc o u r s e,t h e r ei st h ed e s c e n d i n g F i g . 7 Circumf:.~ential d i s t r i b u t i o no ff u e l 巴s si o rc a r b u r e t t o r l i q u i d f i l mt h i c k n f l o wu n d e rt h ei n f l u e n c eo ft h eg r a v i t a t i o n a l o ; e n i n g(E-125) , 。 f o r c ew h i l et h ee v a p o r a t i o nfrom l i q u i d f i l mf l o wp r o c e e d s . S i n c et h i samounto fe v a p o r a t i o ne x c e e d sasumo ft h ed e s c e n d i n gf u e ll i q u i d f i l mf l o w h ef u e l l i q u i d f i l ma tt h e r a t eandt h ef l o a t i n gf u e l d r o p l e tq u a n t i t yadheredt ot h ep i p ew a l l,t bottomw a l l( i . e .p o s i t i o n5 )g r a d u a l l ybecomest h i n n er . Suchat e n d e n c ybecomesmore r e m a r k a b l ew i t hr i c h e rm i x t u r er a t i o( m )a s shown i nF i g .6 . Both come u n d e ra n ft h ed i s t a n c efromt h ef u e lj e to fc a r b u r e t t o rbecomes115mm( i . e e q u i l i b r i u m,however,i p o s i t i o nb )andt h et h i c k n e s so ff u e ll i q u i dイi l md o e sn o ta l m o s tc h a n g e . ② S i n c et h ev e l o c i t yo fb r e a t h i n ga i r( V α =Qa/ f ; )i n c r e a s e sw i t ht h ee n g i n es p e e d( N ), t h ee v a p o r a t i o no ff u e l l i q u i d f i l mi spromotedandi t sq u a n t i t ya p p r o a c h e st oas a t u r a t i o n ( 2 8 1 ) S h i g e n o b uH a y a s h ia n dN o r i h i r oSawa 2 8 2 h ep l a c ea t t a c h e dwitht h ef l o a t i n gf u e ld r o p l e tmovest o w a r d st h ee n g i n e Ont h eo t h e rhand,t s i d e . Thereupon,t h ef u e ll i q u i d f i l mt h i c k n e s so nt h eu p p e rw a l l( i . e .p o s i t i o n1 )d o e sn o t a l w a y sbecomet h i n n e ra tap l a c en e a r e rt ot h ee n g i n es i d eanda l s ot h et h i c k n e s sa tt h e bottomw a l l( i . e .p o s i t i o n5 )d o e sn o tbecomes omucht h i n n er . ③ I ft h eo p e n i n go ft h ec a r b u r e t t o ri ss m a l l( f o rexampleC-1/4),v o r t e x e sa p p e a r si n t h edownstreamo ft h et h r o t t l ev a l v eandf u e ls p r a ya d h e r e sont h ep i p ew a l li nf r o n to ft h e e l e c t r o d ea( l .e . l= 6 5mm).Whilet h ee v a p o r a t i o no ff u e li spromotedandt h ef u e l l i q u i d f i l m a tt h ee l e c t r o d eb(1= 1 1 5mm)t e n d st obecomet h i n n e rb e c a u s eo fh i g hn e g a t i v ep r e s s u r e i nt h ei n t a k ep i p e,t h ef u e l l i q u i d f i l mi sa f f e c t e dbyt h eg r a v i t a t i o n a lf o r c eduet ol o wv e l o 1= 1 6 5mm) c i t yo fb r e a t h i n ga i randbecomesr a t h e rt h i c k e ra tt h ee l e c t r o d ec ( ④ Thee v a p o r a t i o no ff u e ldependsv e r ymucho nt h ea t m o s p h e r i cc o n d i t i o n,t h a ti s, t h et e m p e r a t u r eandt h eh u m i d i t yo fb r e a t h i n ga i rs ot h a t,ont h ec o n t r a r y,t h ef u e l l i q u i d f i l m becomesg r a d u a l l yt h i c k e ra tap l a c en e a r e rt ot h ee n g i n es i d ei nt h ec a c eo fh i g hh u m i d i t y andlowt e m p e r a t u r e . 3 .1 .2 EngineSpeed( N ) Whilet h ec i r c u m f e r e n t i a ld i s t r i b u t i o no ff u e ll i q u i d f i l mt h i c k n e s si nt h eh i g he n g i n e s p e e d( e . g .Nニ 3000rpm,V αニ 1 1 .5m /s)i sa p p r o x i m a t e l y u n i f o r m,whent h el o we n g i n es p e e d ( i . e .b o t ho fGa andGf d e c r e d s e ),t h ef u e ll i q u i d f i l mbecomesg r a d u a l l yt h i c k e rand i t s v a r i a t i o ni sa l s oi n c r e a s e d .Whenl e s st h a n1 0 0 0rpm( V α 5 . 2m/s),however,t h ei n f l u e n c eo f h ec o n t r a r y,t h ef u e ll i q u i d f i l m,i nNニ 6 0 0rpm t h eg r a v i t a t i o n a lf o r c ep r e d o m i n a t e s,ont 二 R ︾ 、 ohm 0 . 5 h mm 〆 I 。 , : C 1 / . ゐ V' 3 31 _ , 452町 も 14/4 5 .02 : l 2/4 ~ Vfm m= 1 1 . 91 . 03 1 1 . 1 1 . 1 3 1 0 . 51 ' " hm 0 . 0 7 9 1 .~~ 0 1 .53 0 . 5 h mm 0 1叩 印 伝 丹 nuhHmnu 円U F O m λ 0 . 5 0. 5 0 . 2 o b F i g . 8 Eff巴c to fe n g i n es p e e do nc i r c u m f 巴I巴n t i a ld i守t r i b u t i o no ff u e ll i q u i d . f i l m t h i c k n e s s( h )呂n df u e ll i q u i d f i l mf l o w r a t er a tlO (Gfl/GA F i g .9 F u e l l i q u i d f i l mt h i c k n e s s( h )a n df l o w o rb r e a t h i n ga i r r a t er a t i o(Gfl/Gl) f a m o u n t ( 2 8 2 ) BEHAVIOROFFUELLIQUIDFILMFLOWI N INTAKEMANIFOLD OF TWOSTROKECYCLEENGINE. 2 8 3 (V α , =1.85m/s), ont h eu p p e rw a l lbecomest h i n n e randt h a to nt h ebottomw a l lr e s u l t st h i c k e r a sp r e s e n t e di nF i g .8 . T h i smakesd e c r e a s e dt h ef l o a t a t i o nandt h ee v a p o r a t i o no ff u e l (presumedont h eb a s i so ft e m p e r a t u r ed e c r e a s eo fm i x t u r e )s ot h a tt h er a t i oo ff u e ll i q u i d f i l mf l o wr a t e(GfdGf )i sg r a d u a l l yi n c r e a s e da sshowni nF i g .8 . d I nt h i sc a s e,t h emeant h i c k n e s so ff u e l l i q u i d f i l mi sg i v e nbyhm=1 / πD Ih . d ze q u a l s t o0 . 0 5 0 . 1 5m m,whichi se x t r e m e l yt h i na si n c l u e di nsamef i g u r e . 。 川 3 .1 .3 Upeningo fCarburettor( C ) h e Whent h ec a r b u r e t t o ri sg r a d u a l l yc l o s e dw h i l et h eo t h e rf a c t o r sb e i n gk e p tc o n s t a n t,t )i sd e c r e a s e dandi tmakest h ei n f l u e n c eo ft h eg r a v i t a meanv e l o c i t yo fb r e a t h i n ga i r(Va t i o n a lf o r c el a r g er . C o n s e q u e n t l y,t h ef u e ll i q u i d f i l mont h eu p p e rw a l lbecomest h i n n e r w h i l et h a tont h ebottomw a l lbecomest h i c k e ra sshowni nF i g .9 . Att h i st i m e,t h er a t i oo f f u e l l i q u i d f i l mf l o wr a t et os u p p l i e df u e l(GfdGf )i sa l s oi n c r e a s e d . Ac o n t r a r yt e n d e n c yt o ns u c hac a s ea st h ei n t a k ep i p ei ss u f f i c i e n t l yl o n gs ot h a t t h i scanbeo b s e r v e d,however,i mosto ft h ef l o a t i n gf u e ld r o p l e ta d h e r et ot h ep i p ew a l l . I nt h i sc a s e,GfdGfwasg i v e nby t h ef o l l o w i n ge q u a t i o n . GfdG l-0.05m.Y f ! r a)/QaU,3 f= ( Where,m i sm i x t u r er a t i o,Yfi ss p e c i f i cw e i g h to ff u e l,ゐ i ss p e c i f i cw e i g h to fb r e a t h i n g 日一 O . 5r h ~ 印 白 川YJ J 1 1 1 J / 干 ? ? ヤ y六 ' t= 1? 9 9 , p m 0 . 6 3 向 日1 8 一 076~ω~m r p Nm 0 . 5 2500 mm I Ka / < 印 手 A C=4/4 日1 1 m 0 . 5 Z 丙 :1) o 0 0 10 20 m 綜 30 F i g .1 0F u e l l i qt,;i d . f i l mt h i c k n e s s( h )a n df l o w )f o r m i x t u r e r a t e r a t i o (Gf1/Gf s t r e n g t h( m ) .. c ^^^ ' C O32)' F i g . l l V呂r i a t i o no ff u e ll i q u i d . f i l mf l o wa t b o t t o mw a l l( m i x t u r er a t i o4-6) ( 2 8 3 ) S h i g e n o b uH a y a s h ia n dN o r i h i r oS a w a 2 8 4 a i r,Qai svolumef l o wr a t eo fb r e a t h i n ga ir . 3 .1 .4 FlowRateo fS u p p l i e dF u e l(Gf) I ft h ef 10wr a t eo fs u p p l i e df u e l(Gf) i sl o w,t h ei Iq u i df u e lont h ep i p ew a l lf l o w sa s u tw i t ht h er i c hm i x t u r es t r e n g t h,i tf o r m sf u e l d r o p l i k eformandi t sv e l o c i t yi sn o th i g h,b i l mf l o w,i t sv e l o c i t yi sa l s oi n c r e a s e dandi t sd i s t r i b u t i o ni nt h ec i r c u m f e r e n c i a l l i q u i df d i r e c t i o nr e s u l t si nh e t e r o g e n e o u sa ss e e ni nF i g .1 0 . Att h i st i m e,s i n c et h ee v a p o r a t i o no f f u e lw i t h i nt h ei n t a k ep i p ei sn o ts omucha l t e r e d( p r e s u m e dont h eb a s i so ft e m p e r a t u r e h er a t i oo ff u e ll i q u i d f i l mf l o wr a t et os u p p l i e df u e l (GfdGf )i s d e c r e a s eo fm i x t u r e ),t )andt h ef u e l l i q u i d f i l m g r a d u a l l yi n c r e a s e d . Themutualr e l a t i o nbetweent h i sr a t i o(GfdGf t h i c k n e s s( h )( i np a r t i c u l a r,a tt h ebottomw a l l )a tt h ee l e c t r o d e( c )o fe n g i n es i d ec a nb ea l s o o b s e r v e di nsamef i g u r e . Suchaf u e l l i q u i d f i l mi smoree a s i l ya f f e c t e dbyp u l s a t i n gwavei f h ei n t a k ep i p ei sl o n g e r,t h er o t a t i o ni so fl o w e rs p e e d,t h ec a r b u r e t t o r t h em i x t u r ei sr i c h e r,t openm 又i sf u l l,c o n s e q u e n t l y,t h el i q u i ds u r f a c ev a r i a t e sv i o l e n t l ya sshowni nF i g .1 1 . Somet i m e s,t h es t a g n a n tf u e l(h=1-3mm)a p p e a r sn e a ran o d a lp l a n e( s = 3 )o ft h ev i b r a t i o no f a i r columni nt h ei n t a k ep i p eandt h es p r a yi sp r o d u c e d . h e na n o t h e r T h i ss p r a ymovess l o w l yw i t h i nt h ei n t a k ep i p eo rd i s a p p e a r ss u d d e n l y,t → 61 0 . 1 ハ-b H 7 1% hm1 E-125 行1 m Eト﹀ 05 0. 。 3 0 1 .5 hm mml 0 . 1 1 j u m p 1.r/N=Eoam 02 F i g .1 2 Mean f l o wv e l o c i t y (Vfm) o ff u e l l i q u i d . f i l m newo n ei son広i n a t e dands of o r t h,t h ec i r c u m s t a n c eb e i n gv e r yi r r e g u l a rand u n s t a b l e . I t a p p e a r s,f o rt h i sr e a s o n,t h a tt h ea i r f u e lr a t i o o fm i x t u r ea c t u a l l ys u c k e di n t ot h e en只me F i g . 1 3 M巴旦 nt h i c k n e s so ff u e l l i q u i d f i l mf l o w c y l i n d e rf 1u c t u a t e sr e m a r k a b l y . ( hm) f o rQfl/Qfa n dQ f l ( 2 8 4 ) BEHAVIOROFFUELLIQUID-FILMFLOWIN INTAKEMANIFOLD OF TWOSTROKECYCLEENGINE. 285 3 .1 .5 FlowRateandThicknessofLiquid-Film Thel i q u i d f i l mf l o wr a t e(QflCC/S)i sgivenby Qft=J:Dj:Vfdh dz Wherei ti sd i f f i c u l tt omeasured i r e c t l yt h ef l o wv e l o c i t yo fl i q u i d f i l m(Vfcm/s),o fwhich t h i c k n e si se x t r e m e l yt h i n( f o rexampleh=O.05-0.5mm). i g .1 2showst h emeanf l o wv e l o c i t yo ff u e l l i q u i d f i l m(Vfm=Qfd7τDhm) c a l c u Now,F : J コゐ) ぉi so f山 meant h i c k n e s s(hm= 1 / πD l a t e dont h eb 川 ec 山山 ir 陀C 削 e 悦 r 日叩 e 叩 n 此t 陀e c t i ω o nぱ 0ff u e l l 日 l q 山 U I idf i l mandぱ 0f出 t hef l o wr a t e( Q f 刀l )o b t a i n e dbyas e p a r a t or . Asc anb e d i r nt h e白 f 1 9 u r 陀e ,a l t h o u g ht h emeanv e l o c i t yo fl i q u i d f i l m(V f m )i sp r o p o r t i o n a lt ot h ef l o w s e e n旧 1 r a t e(QfJ,i ti sn o ta l w a y sp r o p o r t i o n a lt ot h ee n g i n es p e e d( N ),i . e .t h emeanv e l o c i t yo f b r e a t h i n ga i r(Va) . I fi ti sassumedt h a tt h ef l o wv e l o c i t yd i s t r i b u t i o nf o l l o w salowo f1 1 7power,Q f li sg i v e n a sf o l J o w s Qf 刀t 二 β 九 吋L M I t臼 s eemst 出 h抗 att 出 h i si scausedbyt h ei n c r e a s e dmeanf l o wv e l o c i t y,b e c a u s e,undert h e じ 「 ト 」J=1ml 工 1 . 0 l♀立ι 0 . 6 0 . 4 、 G 寸G T , f 0 . 2 0 . 5 下主 。 ミ < c l ' 0 . 1 hm mm 。 5 1 0 15 m 2D F i g .1 4F u e l l i q u i df i l mf l o wr a t er a t i o(Gf,/Gf) a n dmeant h i c k n e s s (hm) f o rm i x t u r e s t r e n g t h( m ) → F i g .1 5 D i s t r i b u t i o no ff u e l l i q u i d f i l mf l o wa n d c a r b u r e t t o ro p e n i n g( 8 ' ) ( 2 8 5 ) 2 8 6 S h i g e n o b uH a y a s h ia n dN o r i h i r oSawa h el i q u i d f i l mo nt h ebottomw a l lbecomesr e m a r k a b l y i n f l u e n c eo ft h eg r a v i t a t i o n a lf o r c e,t t h i c k e randi tr e s u l t st h ei n c r e a s eo fi t sf l o wv e l o c i t yi ns p i t eo fl o w e ra i rv e l o c i t y(Va )a s h emeanf l o wv e l o c i t y(Vf m )d e t e r m i n e dfromt h et i m el a gi n 6 0 0 r p m . I nt h esamef i g u r e,t t h eb e g i n n i n go ff u e l l i q u i d f i l mf l o w, whichi s o b s e r v e dw i t he l e c t r o d e sa tt h r e ep o i n t s( a,b, c, )whent h ee n g i n eh a ss t a r t e d(Ai nF i g . )andt h ev a l u e( B )o b t a i n e dbyamethodt os u p p l y f u e lr a p i d l ybymeanso fr a p i da s c e n to ft h ef l o a tchambera r ea l s oi n d i c a t e d . S i n c et h e meanf l o wv e l o c i t y(Vf m )u n d e rp u l s a t i n gf l o wi ss l o wa so b s e r v e di nt h i sf i g u r e,i tt h u s h e r ee x i s ts e v e r a ls e c o n d so f a p p e a r st h a tevenw i t ha p r a c t i c a ll e n g t ho fi n t a k ep i p e,t s o c a l l e dm a n i f o l dl a g . I na d d i t i o n,t h emeant h i c k n e s s( hm)i sp r o p o r t i o n a lt ot h er a t i oo ff u e l Q f d Q f )a sshowni nF i g s .1 3and1 4,s ot h a ti ti sp o s s i b l e l i q u i d f i l mf l o wr a t et os u p p l i e df u e l( t oe s t i m a t e,byc o n t r a r i e s,QfdQffromt h emeasuredv a l u eo fhm. 3 . 2 . D i s t r i b u t i o no fF u e lL i q u i d F i l mFlowunderS t a t i o n a r yO p e r a t i o n . 3 . 2 . 1 OpeningAngleo fCarburettor( θ ) I ft h ee n g i n es p e e d(N)andt h em i x t u r er a t i o(Ga/Gf) a r ek e p tac o n s t a n t,t h ed e l i v e r y r a t i o( K )showsat e n d e n c yt oi n c r e a s ei np r o p o r t i o n a lt ot h eo p e n i n ga n g l eo ft h r o t t l ev a l v e ( 8 ),ont h eo t h e rhand,t h ed e c l i n a t i o no fb o o s tp r e s s u r eム (p )betweenb o t hc y l i n d e r s( B,C ) d e c r e a s e sw i t ht h a ta sshowni nF i g .1 5 . Ont h i so c c a s i o n,t h er a t i oo ft h ef u e ll i q u i d f i l m ot h es u p p l i e df u e l( Gf),t h es o c a l l e df u e ll i q u i d f i l mf l o w f l o wq u a n t i t y(Gl=Glb+G1C)t q u a n t i t yr a t i o( G z l Gf) i sl i t t l ec h a n g e d . However,a t1 5 0 0rpm,at h r o t t l es e t t l i n go f9 0 d e g r e e s( t h a ti sf u l lo p e n i n g ),t h eamounto fl i q u i d f u e lf l o w i n gi n t ot h ec y l i n d e rB,i no t h e r words,G1b/G1i sl e s st h a n0 . 5 . Ont h eo t h e rhand,whent h eo p e n i n ga n g l eo fc a r b u r e t t o r( 8 ) r e s s u r 巴v a r i a t i o ni ni n t a k ep i p e( P, ) F i g .l(i P F i g .17 P r e s s u r ev a r i a t i o ni nc r a n k c a s e( P c ) ( 2 8 6 ) BEHAVIOR OF FUEL LIQUID-FILM FLOW IN INTAKE MANIFOLD OF TWOSTROKECYCLEENGINE. 2 8 7 i ss m a l l e rt h a n5 0d e g r e e s,t h emoref u e ll i q u i d f i l mf l o w sr a t h e ri n t ot h ec y l i n d e rB s i d e, namely,G 1b/GI i sg r e a t e rt h a n0 . 5 ;B e s i d e s,t h ed i s t r i b u t i o no ff u e l l i q u i d f i l mt r a v e l l i n gt o i n d i v i d u a lc y l i n d e rbecomesr a p i d l yp o o randt h ε nt h es o c a l l e dd i s t r i b u t i o nr a t i o( G 1 b / GI) r e a c h e si n0 . 8t o1 . 0a tt h ec o n d i t i o nt h a tt h ec a r b u r e t t o ro p e n i n ga n g l e( 8 )e q u a l st o30 d e g r e e s( i d l es e t t i n g ) I nt h i s way,t h ee x p e r i m e n t a lr e s u l tt h a tt h e most p a r to ff u e l l i q u f d f i l mi sf l o w e di n t oo n e s i d ec y l i n d e rmeanst omaket h et r u em i x t u r er a t i oi ni n d i v i d u a l c y l i n d e rv e r yu n u n i f o r m,however,t h ep r e s s u r ev a r i a t i o n sd u r i n gi n t a k ep r o c e s si nt h ei n l e t p o r tandc r a n k c a s eo fb o t hc y l i n d e r sa r eo b s e r v e dl i t t l ed i s s i m i l a r i t ya sshowni nF i g s .1 6and ー 1 7 . I fkeepingac o n s t a n tm i x t u r es t r e n g t h(Ga/Gf),t h ed e l i v e r yr a t i o( K )becomesl e s s,and i m i n i s h e sb e c a u s eo ft h es u p p l i e df u e lq u a n t i t y(Gf) t h eamounto ff u e l l i q u i d f i l mf l o w(Gl) d d e c r e a s e sw i t ht h ed e l i v e r yr a t i o( K ) . But,s i n c et h er a t i oo ft h ef u e l l i q u i d f i l mt r a v e l l i n go nt h eo n l ybottoms u r f a c et ot h a to n t h ew h o l ec i r c u m f e r e n c ew a l lo fi n t a k ep i p ei si n c r e a s e dbyt h ee f f e c to fg r a v i t a t i o n a lf o r c e ti sr e s u l t e dt h a tt h ec i r c u m f e r e n c ed i s t r i b u t i o no ff u e l andt h e nt h er o t a t i v ef l o wo c c u r s,i l i q u i d f i l mbecomesv e r yununiforma sshowni nF i g .1 8 . C o n c e q u e n t l y,i tt h u sa p p e a r st h a t t h em a l d i s t r i b u t i o no ff u e l l i q u i d f i l mt h i c k n e s sh a sal a r g ei n f l u e n c eont h ed i s t r i b u t i o no fi t s f l o wq u a n t i t yanda l s ot h es m a l l e rt h ea b s o l u t ev a l u eo ft h a t(Gl) becomes,t h el a r g e rt h e G 1 b / GI) r e s u l t si n . d i s t r i b u t i o nr a t i o( 3 . 2 . 2 MixtureRatio(Ga/Gf) 工 E ;2トト~_ 「 88jl15守 1 一 ¥ 又 ヘ 一 / ノ/////ノ/ μMM メ 0 .2 0 .. 4 1 」 ~'" 宇 , , 3 0 ヱ ト ー 1 一 ハU 1 、¥、¥¥、 i 、 ¥11 All、 、 /'fケlllI 。 i 8 M U mp-J 0 . 2 pm サトナイ _ _ /_ / 人 J7 Q 3 5 6 7 9I l N = 1 2 . o 0 . F i g .1 8 D i s t r i b u t i o no ff u e ll i q u i d f i l m f l o wi ne a c hp o s i t i o n, 品 (b ,c ) - " 《 A 令)十=r=--=J 30 . 60 . I 90 . 80 F i g .19 D i s t r i b u t i o no ff u 巴l l i q u i d f i l mf l o wa n d m i x t u r er a t i o(Ga/Gf) ( 2 8 7 ) 2 8 8 S h i g e n o b uH a y a s h ia n dN o r i h i r oSawa Whent h es u p p l i e df u e lquantityi sg r a d u a l l ydecreasedwhilet h eo t h e rc o n d i t i o nbeing keptac o n s t a n t,t h ed e l i v e r yr a t i o( K )i sl i t t l ev a r i a t i o na sshowni nF i g .1 9 . Consequently, t h e、evaporationo fl i q u i d f u e li nt h ei n t a k emanifoldi spromoteds ot h a tt h ef u e ll i q u i d f i l m flowr a t i o( GtlGf )becomesl e s s,t h ed i s t r i b u t i o nr a t i o( G 1 b / Gf )i si n c r e a s e d . I ti sseemedby t h er e a s o nt h a tt h el e a n e rt h emixturer a t i o( G a/ Gf )becomes,t h a ti s,t h es m a l l e rt h es u p p l i e d f u e lq u a n t i t y(Gβbecomes,t h el a r g e rt h ei n f l u e n c e so fmicroscopicshaped e v i a t i o ni nbranch p a r tando funiformt h i c k n e s so ff u e ll i q u i d f i l moni t sd i s t r i b u t i o nbecomes. Now,i fi ti s h e assumedt h a tt h ef l o a t i n gf u e li ni n t a k emanifoldi se q u a l l yd i v i d e di n t oeachc y l i n d e r,t r e l a t i o nbetweent h ee s s e n t i a lmixturestrength(Ga/ Gf)ini n d i v i t u a lc y l i n d e randt h emixture G a/ Gf )suppliedfromacarburettori sgivenby r a t i o( 全 . ! > _ _) 一 、 (Ga/Gf)/{Ga/Gf)= (1十 字 (1-2 、 Jf l Jl Ther o u g hc a l c u l a t e dr e s u l tw i t ht h ee x p e r i m e n t a ld a t a(G1b/GI,GtlGf )o b t a i n e dfrom r e s e n t st h a tt h es m a l l e rn o to n l yt h ec a r b u r e t t o ro p e n i n g F i g .1 9a r eshowni nt a b l e3,whichp ( 8 )a nda l s ot h em i x t u r er a t i o(Ga/ Gf )b ecomes,t h ep o o r e rt h em i x t u r ed i s t r i b u t i o nbetween )b e c o m e s . b o t hc y l i n d e r s( B,C i N ) 21] 1 I G . l G f1 =0 3 . 2 . 3 EngineSpeed( A l t h o u g ht h ed e l iv e r y叫 o(K)lncmm gJ 宇守主主」ーとゴ w i t ht h ee n g i n es p e e d( N )a su n d e r s t o o dfrom 0 . 8 F i g .2 0,t h ef u e ll i q u i d f i l mf l o wr a t i o(GtlGf ) ヱ i sn o ta l m o s tchangedw i t h i nt h er a n g eo ft h i s 0 . 5 2 0 0-2 0 0 0rpm). But i t e x p e r i m e n t( i . e .N=1 a p p e a r so r d i n a r i l yt h a tt h ei n c r e a s eo fd e l i v e r y r a t i o( K )a c t sa su n i f o r mf o rt h ec i r c u m f e r e n - 0 . 2 t i a ld i s t r i b u t i o no ff u e l l i q u i d f i l mt h i c k n e s s( h ) 1 np a r t i c u l a r,t h ed i s t r i b u t i o ni nt h e s ot h a t,i c a s eo fs m a l lt h r o t t l es e t t i n gi simprovedand N= GI)o wing t h ec h a n g eo fd i s t r i b u t i o nr a t i o(G1b/ 2 0 0 0 ' 1 5 0 0 8 ),f o r example, t ot h ec a r b u r e t t o ro p e n i n g( 1 2 0 0r p m t h ed i f f e r e n c eo fd i s t r i b u t i o nr a t i obetween8 =30deg.and9 0d e g .becomess m a l . l 0 2 4 I n c l i n e dAngle (β) o f Intake Mani- β 0 3 . 2. fuW ~ Asar u l e,t h ed e l i v e r yr a t i o( K )d e c r e a s e s 8 )a nda l s ow i t h w i t ht h ec a r b u r e t t o ro p e n i n g( ot h a tt h er a t i oo ff u e l t h ee n g i n es p e e d(N)s l i q u i d f i l m f l o wq u a n t i t y f l o w i n g o n t h e 乙et ot h a to nt h ew h o l ei n s i d ew a l l bottoms u r f a o fah o r i z o n t a li n t a k ep i p ei si n c r e a s e dbyt h e O0 3 i n f l u e n c eo fg r a v i t a t i o n a lf o r c e ( 2 8 8) 、 h 事Y 。 jU 司刻V 戸 内 M 、 。 F i g . 2 0D is t r i b u t i o no ff u e l l i q u i d . f i l mf l o wa n d e n g i n es p e e d( N ) BEHAVIOR OF FUEL LIQUIDFI LM FLOW I NI NTAKE MANI FOLD OF TWOSTROKECYCLEENGINE Ons uchano c c a s i o n,i ft h ei n c li neda n g l e N = 1 2 0 0r p m G . / G ' s f6 6 。 寸 ﹂ 。 門U f外 勺 ↑ │ │ │ ﹂ ー ﹁ー ー c 恥の¥ つ4Fb n u n u L - 円U G l b/ Gl )i sr emar kab l yvar ieda s t ri b u t i o nr a t i o( showni nF i g _2 , 1f o rexample,w i t hat h r o t t l e s et t i n go f3 0d e g _,G l b/ Gli schangedfrom0. 2 a ts =-1 0d e g _t o0 . 9a ts =Od e g . . Accor d i ng l y,i faa u t o m o b i l eengi nei so p e r a t e da tt he pa r t ia ll o a d,i n addi t ion t ot h a t,t h ei nt a k e m a n i f o l di ss l i g h t l yi n c l i nedo rt h emechan ical v ib r a t i o ni so c c u r e d,i ti scon je c tu redfromt h e r e su l tmentionedabovet h a tt h ed i s t r i b u t i ono f f u e ll i q u i df i l mf l o w be c omesv e r yp o o r and y e tuns t e a d y . 6 ¥ B o ( β )o fi n t a k em a n i f o l di s changed,t he d is - 2 8 9 ト グ ←4 F i g . 2 1D is t r ib u ti o no ff u e l li q u i d f i l mf l o wa n d i nc l i n e da n gl e( β lo fi n t a k em a n i f o l d 3 . 2 . 5 I n l e tPipeLength( L s ) When t h ep ipe l e n g t h( L s ) between t h e c a r b ur et t o r and t h eb r a n c hp a r to fi n t a k e m a n i f o l di sv e r yl ong,t h ede i lv e r yr a t i o( K )i s no tchangea tt h er a n geo fθ < 5 0.o rr a t h e r L. d e c r e a s e sa te>5 0.a ss howni nF i g .2 2 . On ' : ' : : 05 t he o t h e r hand, s i nc et h ef uell i q u i df i l mi s . 4 evap o r a t e dwh i lef l o w i n gtowardt he s e p ar a- 0 t o r,t h et h i c kne s sbecomesgradua lyt h i nand 0 3 i ti sr e su l t e dt h a tt h ef u e l l i q u i d f i l mfowr a t i o N=2 0 0 0 ( GdGf)f o rt h el ongpi pei ssma le rt h a nt h a to f r p π、 ら/ G 旬 。= 1 0 t h es h o r tl e n g t h . Moreover,t h el i q u i d-f u elj us tadheredon 06 t hep ipew a l la f t e ri n je c t e do u tacar b u r e t t o ri s uns t e a d ys t a t eanda l s ov e r yt u r b u l e n t,b u ti t a p p r o a c h e st h es t eady s t a t ea nd t h e nt h e t u r b ul ence i sd e c l i n e di np r o p or t ion a st h e l i q u i dfi l mp r o ce edstowar dt h eengi n ecyl i nd e rvi ai n t a k em a n i f o l d . Onaccounto ft h e s e e f f e ct s ,t h el o n g e rt h ea d d i t i o n ali n t a k epi pe l e n g t h( L s )fromt hec a r b u r e t t ort ot h eb r a nc h 3 0 60 9 0 e。 p a r tbecomes, t hebl o !t t e rt hed i s t r i b u t i o no f F i g. 2 2D is t r i b u t i o no ff u el l iq u i df il mf l o wa n d l i q u i d f i l mbecome s . i n t a k ep i p el e n g t h( L s l ta p p e a r st h a tt h es m a l l e rt h e E s p e c i a l l y,i t h r o t t l es e t ti ngo fc a r b u r e t t o r( θ )andt h e nt h es u p p l ied f u e l (Gf) a r ek e p t, t h el a r ge ri t s 長一一ト斗 -O¥ad ーー﹂ 6¥-O ﹁Illl ﹁ i 似邸 1 e f f o r tbecomes 3 . 2 . 6 Kindo fF u e l twasu n a v o i d a b l efromar e a s o nmenAlthought h er e g u l a rg a s ol i newasm a i n lyused,i ( 2 89) S h i g e n o b uH a y a s h ia n dN o r i h i r oSaw 呂 290 aE ﹁占 b ハ 。 Ga/G誌8 1υ 兵 士 官 工 印 山 内 三ο N=1200rpm 02 02 06 30 60 90 8 0 F i g .2 4 D巴v i a t i o no f mean f u e ll i q u i d f i l m s t h i c k n巴s c . 9 ¥、 。03 。 30 60 90θ 。 F i g . 2 3D i s t r i b u t i o no ff u e l l i q u i d f i l mf l o wa n d k i n do ff u巴i A:M e t h a n o l G: G a s o l i n e F i g .2 5R e s p o n s eo ff u e lf l o w( E 1 2 5 ) A .F .: A i rf l o wr a t e( la m i n a r ty p e df l o wm e t e r ) F .F .: F u e lr a t巴 ( c a p a c i t y t y p巴df l o wm e t e r ) u g 巴 P .P . P r e s s u r ei ni n l e tp o r t( s t r a i n耳a t y p e di n d i c a t o r ) t i o n e da tt h ee x p e r i m e n t a lmethods ot h a tmethanoli n s t e a do fg a s o l i n ewasusedt omeasure t h et h i c k n e s so ff u e ll i q u i df i l mf l o w( h ) . But,i ns p i t eo f some d i f f e r e n c eo fp h y s i c a l a t e n th e a t,s u r f a c et e n s i o nanda e n s i t ye t c .,i t c h a r a c t e rbetweenb o t hf u e lf o r example, l canbeknownfromF i g .2 3t h a tt h ed i s t r i b u t i o nr a t i o(Glb/G1) i sn o tm o s t l yd i f f e r e n c e . I n I 1 t h en e x tp l a c e,t h emeant h i c k n e s so ff u e l l i q u i d f i l mI hm=一云 ¥ r1CD I 7 r Lノ . 10 ¥ h'dzJi ne a c hp o i n t I ( B,C )c a l c u l a t e dw i t ht h ee x p e r i m e n t a lv a l u eo fi t sc i r c u m f e r e n t i a lt h i c k n e s sandt h es o h m b / ( hm 十 h m c ) J a r e a r r a n g e d a g a i n s t c a l l e dd i s t r i b u t i o nr a t i oo ff u e ll i q u i df i l mt h i c k n e s s( b t h ec a r b u r e t t o ro p e n i n g( 8 )i nF i g .2 4 . Ascompared t h e s e witht h ee x p e r i m e n t a lr e s u l t s shown i nF i g .1 5,t h emutual r e l a t i o n s h i pbetweent h ed i s t r i b u b o no ff u e ll i q u i d f i l mf l o w q u a n t i t y ando fi t st h i c k n e s si ss u f f i c i e n t l ye s t i m a t e d 3 . 3 Behavioro fF u e lLiquid-FilmFlowunderT r a n s i t i o n a lOperation 3 . 3 . 1 GeneralBehavior G e n e r a l l y,a l t h o u g hs u c has m a l l s i z e dc a r b u r e t t o ri sc o m p a r a t i v e l ys u p e r i o ri nt h e h emosto fi t sf u e la r esucked i n d i c i a lr e s p o n s eo ff u e li n j e c t e dfromaf u e l j e t( s e eF i g .2 5 ),t i n t ot h ee n g i n ec y l i n d e ra sl i q u i d,i tt h u sa p p e a r st h a tt h eb e h a v i o ro ff u e l l i q u i d f i l mf l o wh a s ar e m a r k a b l ei n f l u e n c eo n,i np a r t i c u l a r,t h em i x t u r ef o r m a t i o nd u r i n gat r a n s i t i o n a lr u n i n g andt h em i x t u r ed i s t r i b u t i o ni nm u l t i c y l i n d e re n g i n e . Accordingt ot h ee x p e r i m e n t a lr e s u l t i nF i g .2 6,i ti so b s e r v e dt h a tt h eb e h a v i o ro ff u e l l i q u i d f i l mt h i c k n e s si nt h ei n t a k ep i p e(T2, T3) i sc l o s e l yr e l a t e dt on o to n l yt h a ti nt h es c a v e n g i n gp a s s a g e( S z,S 3 )anda l s ot h ea s p e c to f f u e lv a p o u rc o n c e n t r a t i o n (E3 )o b t a i n e d from t h ee l e c t r i c a lc o n d u c t i v i t yi nt h ee x h a u s t m i x t u r efromt h ec y l i n d er . p e r a t e das i n g l ec y l i n d e re n g i n ebyu s i n gmethanoli n s t e a do fg a s o l i n ea s S i m i l a r y,weo ( 2 9 0 ) BEHAVIOR OF FUELLIQUID-FILM FLOW I N INTAKE MANIFOLD OF TWOSTROKECYCLEENGINE. 2 9 1 f u e landr e c o r d e dt h eb e h a v i o ro ft h ef u e ll i q u i d f i l mt h i c k n e s sa sw e l la st h emaximum c o m b u s t i o np r e s s u r e( P )w h i l eo p e n i n gr a p i d l yt h et h r o t t l ev a l v eo f ac a r b u r e t t or . The c o r r e l a t i o nbetweent h eb o t ha r eo b s e r v e dfromt h eo x p e r i m e n t a lr e s u l tshowni nF i g .27and a l s oi ti su n d e r s t o o dt h a tt h eb e h a v i o ro ff u e l l i q u i d f i l mf l o wi nt h ei n t a k em a n i f o l dh a v ea l a r g ei n f l u e n c eo nt h em i x t u r ef o r m a t i o n,t h a ti s,t h ec o m b u s t i o ns t a t ed u r i n gat r a n s i t i o n a l runmng. A l t h o u g h: i h eb e h a v i o ro ff u e ls u p p l yc o n d i t i o nu n d e rt h et r a n s i t i o n a lo p e r a t i o ni s ti sp o s s i b l et oo b t a i ne a s i l yt h ei n s t a n t a n e o u sf l o wr a t eo f c o m p l i c a t e da smentioneda b o v e,i f u e lp r a c t i c a l l ys u c k e di n t ot h ee n g i n ec y l i n d e r ( G f ; ( t ) ) i ft h ef u e l l i q u i d f i l mt h i c k n e s si nt h e c i r c u m f e r e n t a i landl o n g i t u d i n a ld i r e c t i o no ft h ei n t a k ep i p ea r ea p p r o x i m a t e l yu n i f o r m h a ti s 'r o u g h l yg i v e nby A c c o r d i n g l y,t G f ; ( t )ニ Gjt)-d G f l ( t ) / d t WhereG) t )i st h ei n s t a n t a n e o u sf u e lf l o wr a t es u p p l i e dfromac a r b u r e t t o r,G f l ( t )i st h e i n s t a n t a n e o u sf u e ll i q u i d f i l mf l o wr a t e . Letu snowassumet h a tt h ef l o wv e l o c i t yo ff u e l )i sp r o p o r t i o n a lt ot h eb r e a t h i n ga i rv e l o c i t y(Va)andt h ef o r m e r ' sd i s t r i b u t i o n l i q u i d f i l m(Vf f o l l o w sal o wo f1 / 7power,t h e n i l l Gf t )= Gf( t )一 β・ Vah1/ 7 ( t )互 主 i( d t I ft h ei n s t a n t a n e o u st h i c k n e s so fl i q u i d f i l mh ( t )i sa c t u a l l ymeasured,c o n s e q u e n t l y,i t r a c t i c a l l ys u c k e d i sp o s s i b l et oknowt h eb e h a v i o ro fd i f f e r e n c e -(Gfi(t)-Gjt)) between p 門ーp r ー . . . . . . . , ' r l / 一"IH I Dyn• ! = 1M 、 n C I I H ~ )!二二三コ E二工l I一 ← 』 40 . . . 4 且 20 。 ; │ 2 仰 ; : f J i i J 1 1 ノ ザR 北山 l f ) 1 0 0 0 5 2 1 二 ご 十 一 つ イ叱:卿 宍 己 ユJ V】 T 2 u Z H T e c 3 s F i g .2 6M u t u a lr e l a t i o nb e t w e e nb e h a v i o ro f f u e ll i q u i d f i l mt h i c k n e s si ni n t a k e p l p e,ms c a v e n g m gp a s s a g e ( 2 9 1 ) 2 F i g . 2 7C o m b u s t i o nmaximump r e s s u r e( p )a n d 巴s s(H) f u e l l i q u i d f i l mt h i c k n 292 S h i g e n o b uH a y a s h ia n dN o r i h i r oSawa h ( t ) / d t > ands u p p l i e df u e l s . Thati s,whend 0,G f i ( t ) < G j t )andv i c ev e r s a . Withsucha n h ea u t h o r s have measured t h e i n f e r e n c e, t v a r i a t i o no ff u e l l i q u i d f i l mt h i c k n e s swhent h e c a r b u r e t t o rh a s been r a p i d l y opened and c l o s e d . Theo u t l i n eo fr e s u l t so b t a i n e da r ea s f o l l o w s 3 . 3 . 2 Opening and C l o s e i n g Speed o f Carburettor I ft h et h r o t t l ev a l v eo fc a r b u r e t t o ri s 。 1 百 o t hb r e a t h i n ga i randf u e la r e F i g .2 8V a r i a t i o no ff u e l l i q u i d f i l mt h i c k n e s s s l o w l yopened,b s u p p l i e dw i t h o u tanyt i m el a g( s e eF i g .2 5 ), b u tt h er e s p o n s eo ff u e ll i q u i d f i l mf l o wi s i n f e r i o rs ot h a tt h ef u e ll i q u i d f i l mt h i c k n e s s a t t a i n sav a l u ea tt h es t a t i o n a r yc o n d i t i o no n l y dh(t) a f t e ri tbecomeso n c et h i c k e r~一一一> 0a s t 1 / 5吟 % d t 3 showni nF i g .2 8 Perhapst h i smeanst h a tt h e s d i f f e r e n c ebetweens u c k e dands u p p l i e df u e l 5 becomesn e g a t i v e,a tf i r s t,t h a ti s,t h em i x t u r e r a t i oi sweakert h a nt h es e t u pv a l u eandt h e n i t becomes p o s i t i v e, c o n s e q u e n t l y, r i c h e r m i x t u r eands of o r t ht oa t t a i nf i n a l l yt h econ d i t i o no fas t a t i o n a r yr u n n i n g( t h i s pheno menoni so f t e nr e a l l i z e di nt h ec a s eo falow ft h e e n g i n es p e e dandal o n gi n t a k ep i p e ) . I h e u c a r b u r e t t o ri s r a p I d l y opened,however,t f u e ll i q u i d f i l mf o l l o w st h ei n v e r s ec o u r s e ち Thati s,t h ef u e l l i q u i d f i l mb e g i n st obecome r a p i d l yt h i n n e rs l i g h t l ya f t e rt h eo p e n i n go f t h ec a r b u r e t t o r and r e t u r n ss l o w l yt ot h e s t a t i o n a r yt h i c k n e s sa f t e raw h i l ea sshowni n F i g .2 9( i nt h ec a s eo fah i g he n g i n es p e e d w i t has h o r ti n t a k ep i p e ) . 3 . 3 . 3 EngineSpeed( N ) S i n c e,i ng e n e r a ,l t h ef u e ll i q u i d f i l mch a n g e sa s showni nF i g .2 9,t h ei n f l u e n c e so f 斗ど宇ヲつ 正 一 可 喧 p r e s c r i b e de n g i n es p e e d(N) onb e g i n n i n go f t h i c k n e s sr e d u c t i o n( t1),t h et i m e( tz)whent h e F i g . 29 R e s p o n s et i m el a g( t d 2ん) o ff u巴l l i q u i d . f i l mt h i c k n e s s l i q u i d f i l mbecomest h i n n e s te t c .a r ei n v e s t i g a t e d Thoser e s u l t sa r ei n c l u e di nsamef i g u r e .A c c o r d i n gt ot h ef i g u r e,t h emoret h ee n g i n e s p e e di sh i g h,t h emoret h echangeo fa i rf l o wv e l o c i t y(Vα)c a u s e dbyt h eopenedc a r b u r e t t o r ( 2 9 2 ) BEHAVIOROFFUELL I Q U I D F I L MFLOWI NINTAKEMANIFOLDOF TWOSTROKECYCLEENGINE i sl a r g er . C o n s e q u e n t l y,t h er e s p o n s et i m el a g ( t1,t z )o ff u e ll i q u i d f i l mt h i c k n e s s become s h o r t e rb u t ont h eo t h e r handt h et i m e( t3) whichi sn e c e s s a r yt or e t u r nt oas t a t i o n a r y s t a t ebecomesl o n g e rw i t hs l o wc h a n g e,s ot h a t i ti sd i f f i c u l tt od e c i d et h ec o r r e c tv a l u e . I n . l a r g e rd i s p l a c e m e n t( e . g .C-1/5 t h en e x tp l a c e, → 4 / 4 )o ft h r o t t l ev a l v ec a u s e sl a r g e rc h a n g e o ff u e ll i q u i d f i l mt h i c k n e s s and l a r g e rr e s p o n s el a g( tz . ) 293 15 10 N二 150 0 , pm F i g .3 0R e s p o n s 巴t i m el a g(らん)o ff u e l l i q u i d f i l mt h i c k n e s s 4 M ixtureR a t i o( m ) 3 . 3. Thef u e ll i q u i d f i l m ont h e bottom w a l l becomest h i c k e ri ft h em i x t u r ei se x c e s s i v e l y h er e s p o n s i v e r i c h . Unders u c hac o n d i t i o n,t n e s so ff u e ll i q u i d f i l mf l o wi sc o m p a r a t i v e l y b e t t e r,t h a ti st . 2s e c .,t =1 .5s e c .when 1=0 z t h em i x t u r es t r e n g t he q u a lt o5 . 5 . Moreover, t t n c r e a s ew i t ht h em i x t u r er a t i oa s 1, 3i zandt 10 showni nF i g .2 9 . T h i smeanst h a tt h emore r i c hc o n d i t i o no fa c t u a ls u c k e dm i x t u r et h a n s e t u pv a l u ec o n t i n u e sf o ra b o u ttwos e c o n d s andf u r t h e rs e v e r a ls e c o n d sa r en e c e s s a r yu n t i l as t a t i o n a r yc o n d i t i o ni sr e a l i z e d . I nt h i sway, J 斗k、ノ?代 -- I ¥ " . I o n ec a nu n d e r s t a n dt h a tt h ee x i s t e n c eo ff u e l m m 1c/ ,--ご¥ 0 2 ト γ 、-"-ー l i q u i d f i l mf l o wi nt h ei n t a k ep i p eh a sal a r g e トーー~ a i n f l u e n c eont h ef u e ls u p p l yc o n d i t i o nd u r i n ga 。」←ー「ーーー→ーー→一一←ー→ー十一寸 t r a n s i t i o n a lr u n n i n g 3 . 3 . 5 C a r b u r e t t o r Opening ( C ) and P i p e Length( L s ) 1 5 0 0 ト ー m=10.4 I I m=1 4 . 0 __________ The r e s p o n s el a go ft h ef u e ll i q u i d f i l m N rpm I n c r e a s ew i t ht h e 5 t h i c k n e s s ( t1,t I I I 0 01 zandt 3) i 8 T1 2 ' : , e c c h a n g eo ft h r o t t l ev a l v eo fc a r b u r e t t o rム (C)and F i g .3 1B e h a v i o ro ff u e ll i q u i d f i l mt h i c k n e s s t h el e n g t ho fi n t a k ep i p e( L s )a sshowni nF i g . d u r i n gt r a n s it i o n a lo p e r a t i o n 2 9and3 0 . ι : 8 C “│ J r--一一~ 4 Di s t r i b u t i o no fF u e lL i q u i d F i l mFlow 3. underT r a n s i t i o n a lOperation Wer e c o r d e dt h eh i s t o r yo ff u e l l i q u i d f i l mt h i c k n e s sw h i l ec h a n g i n gr a p i d l yt h eo p e n i n g o rt h ep u r p o s eo fknowingt h eq u a l i t a t i v eb e h a v i o r o fc a r b u r e t t o r( 8 )o rt h ee n g i n es p e e d(N)f ont h ed i s t r i b u t i o no ff u e l l i q u i d f i l mf l o wq u a n t i t y . Thet y p i c a lr e s u l t sa r ep r e s e n t e di nF i g . nwhich showt h eb e h a v i o ro ff u e ll i q u i d f i l mt h i c k n e s sw h i l et h et h r o t t l ev a l v eo f 3 1,i h er e s u l td u r i n g an a c c e l e r a t i n g c a r b u r e t t o ri sr a p i d l y openedo rc l o s e d . Moreover,t ( 2 9 3 ) 2 9 4 S h i g e n o b uH a y a s h ia n dN o r i h i r oS a w a o p e r a t i o nw i t hf u l lt h r o t t l eshowni nF i g .3 1 D shows t h eh i s t o r yo fi t st h i c k n e s su n d e ra r a p i d l yo p e nt h r o t t l ea c c e l e r a t i o ns t a r t e dfrom ヘー叫 1 0 0 0r p m . . Fromt h e s ef i g u r e s,i ti ss e e nt h a t t h et h i c k n e s so ff u e ll i q u i d f i l mf l o w i n gt o i n d i v i d u a l c y l i n d e r show t h e d i f f e r e n c i a l b e h a v i o ra ta l lt h ee n g i n eo p e r a t i n gc o n d i t i o n, i np a r t i c u l a r,t h et h i c k n e s sb e f o r et h ec a r b u r e t t o ro p e n i n gi schanged a f f e c t sl a r g e l yo n 1 5 5 t h e s eb e h a v i o r . Suchat e n d e n c yi sshowni n e v e nt h ec a s eo fd e c e l e r a t i n go p e r a t i o na s p r e s e n t e di nF i g .3 2,whichshowst h er e s u l t s d u r i n go n l yad e c e l e r a t i n gr u n n i n gw i t hf u l l _C t h r o t t l e and u n d e rar a p i d l yc l o s et h r o t t l e d e c e l e r a t i o ns t a r t e d from 2 0 0 0r p m . . How e v e r,s i n c et h es u p p l i e ds t a t e so ff u e ll i q u i d f i l mf l o wd u r i n gat r a n s i e n tr u n n i n ga r e complexa sm e n t i o n e da b o v e, i ti sn e c e s s a r y t op e r f o r mt h eq u a n t i t a t i v ee x p l a n a t i o nont h e F i g .3 2B e h a v i o ro ff u e ll i q u i d f i l mt h i c k n e s s d i s t r i b u t i o no ff u e ll i q u i d f i l mf l o wq u a n t i t y d u r i n g t r a n s i t i o n a . l ando nt h ei n f l u e n c eo fv a r i o u sf a c t o r si no r d e r t oe l i m i n a t eat r a n s i t i o n a ls t a t efromas t a t i o n a r yr u n n i n g . ;斗ー斗ν ヰ 三j- 4 . P o s t s c r i p t Thea u t h o r sh a v emeasuredt h ef u e l l i q u i d f i l mt h i c k n e s sfromi t se l e c t r i cc o n d u c t i v i t y andt h ef l o wr a t ew i t has e p a r a t o rt oi n v e s t i g a t et h eb e h a v i o ro ff u e ll i q u i d f i l mf l o wa s t a t i o n a r yo p e r a t i o n ,t h ei n f l u e n c eo fr u n n i n gc o n d i t i o no nt h ef u e l l i q u i d f i l mf l o wr a t e .We h a v ef u r t h e ri n f e r r e di t sf u e ls u p p l yc o n d i t i o nont h eb a s i so ft h eb e h a v i o ro ff u e l l i q u i d f i l m t h i c k n e s su n d e rat r a n s i t i o n a lo p e r a t i o n,p o i n t e do u tt h a tt h ef u e l l i q u i d f i l mf l o wh a sal a r g e i n f l u e n c eone f f e c t i v em i x t u r ef o r m a t i o nandh a sd e s c r i b e d,a tt h esamet i m e,t h ei n f l u e n c e o fr u n n i n gf a c t o r s . I ng e n e r a ,l w i t hl o we n g i n es p e e dands m a l lo p e n i n go fc a r b u r e t t o r,t h ed i s t r i b u t i o no f f u e ll i q u i d f i l mt oi n d i v i d u a lc y l i n d e ri nm u l t i c y l i n d e re n g i n ei sv e r yp o o r .Andy e t,t h e d i s t r i b u t i o ns t a t ea r eg o v e r n e dbyt h ed i m e n s i o no fi n t a k em a n i f o l dandt h ee n g i n eo p e r a t i n g c o n d i t i o n s .Moreover,i ti ss u r m i s e dfromt h eb e h a v i o rl i q u i d f i l mt h i c k n e s st h a tt h ef l o w h e r e f o r e,i ti sn e c e s s a r y d i s t r i b u t i o nd u r i n gat r a n s i t i o n a lr u n n i n gi sr e m a r k a b l yu n u n i f o rm.T t oc e r t i f yi nd e t a i lt h ee f f e c t so fv a r i o u sf a c t o r sv e r s u st h ed i s t r i b u t i o n . ( R e c e i v e dM a y .2 2,1 9 7 6 ) ( 2 9 4 ) BEHAVIOROFFUELLIQUID-FILMFLOW I NINTAKEMANIFOLD OF TWOSTROKECYCLEENGINE. 2 9 5 R e f e r e n c e s ( 1 )N .Sawa,S .H o r i:Ont h eBeh a v i o ro fF u e lL i q u i d F i l mThickn 巴s si nt h eI n t a k eP i p e .]ARIT e c h .Memo, N o .2( S e p .1 9 7 1 ) ( 2 ) D .E .C o o p e r,e ta . l:R a d i o a c t i v eT r a c e r sC o s tNewL i g h tonF u e lD i s t r i b u t i o nSAET r a n s .,Vo . l67,1 9 5 7 . ( 3 ) M .H .C o l l i n se ta . l AT echniquet oC h a r a c t e r i z eQ u a n t i t a t i v e l yt h eA i r/ F u e lM i x t u r 巴 i nt h 巴 I n l e t 9 6 9 ) M a n i f o l do faG a s o l i n eE n g i n eSAEP a p e r,690515(May,1 ( 4 ) ] .S .C l a r k e: I n i t i a t i o nandSomeC o n t r o l l i n gP a r a m e t e r so fCombustioni nt h eP i s t o nE n g i n eP r o c .IME, N o .5 .1969-61 . ( 5 ) D .R .L i i m a t t a: E f f e c t so fM i x t u r eD i s t r i b u t i o nonE x h a u s tE m i s s i o n sa sI n d i c a t e dbyE n g i n eD a t aandt h e Ju ne1 9 7 1 ) H y d r a u l i cAnalogySAEP a p e r,710618( ( 6 ) M.Tanaka:A Studyo ft h eFlowo fF u e lF i l ma l o n gt h eW a l lo ft h eI n d u c t i o nP i p e( ls tR e p o r t )]A 悶 , T e c h n i c a lMemorandom,N o .1( S e p .1 9 7 0 ) ( 2 9 5 )
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