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Ng Quang Tun 44DLOT n tt nghip
MC LC
LI NI U ................................................................................................................ 1
CHNG 1. TNG QUAN ..........................................................................................31.1.Nhin liu thay th .........................................................................................3
1.1.1 Cc ch tiu k thut ca nhin liu Diesel...............................................3
1.1.1.1 Nhit tr.............................................................................................3
1.1.1.2 nht .............................................................................................5
1.1.1.3 Tnh t bc chy ...............................................................................5
1.1.1.4 Hm lng tp cht ...........................................................................7
1.1.2 Nhin liu biodiesel .................................................................................9
1.1.2.1 Khi nim .........................................................................................9
1.1.2.2 Tnh hnh sn xut v s dng Diesel sinh hc t du thc vt ........10
1.1.2.3 c tnh ca biodiesel .....................................................................12
ESTER ............................................................................................................... 12
Metyl du ci ..............................................................................................12
1.1.2.4 Qu trnh iu ch biodiesel. ...........................................................13
1.1.3 Nhin liu LPG (Liquefied Petroleum Gases) ........................................15
1.1.3.1 Khi nim LPG ...............................................................................151.1.3.2 Tr lng LPG v th trng tiu th ..............................................16
1.1.3.3 c tnh nhin liu kh ha lng......................................................17
1.2.ng dng nhin liu thay th cho ng c diesel xe but Thnh Ph
Nha Trang..........................................................................................................22
1.2.1 Gii thiu chung v xe but Thnh Ph Nha Trang ............................22
1.2.1.1 S lc v xe but Thnh Ph Nha Trang ....................................22
1.2.1.2 Thng s k thut ca xe but Thnh Ph Nha Trang ..................23
1.2.2 c im k thut v cu to ca ng c D6BR s dng trn xe butThnh Ph Nha Trang .................................................................................29
1.2.2.1 Gii thiu chung v v tr ng c trn xe but................................29
1.2.2.2 c im k thut ca ng c.......................................................29
1.2.2.3 Nhm piston, xylanh, np xylanh ....................................................31
1.2.2.4. H thng nhin liu ........................................................................36
1.2.2.5 H thng np - x ............................................................................48
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CHNG 2. KH NNG S DNG NHIN LIU THAY TH CHO I
XE BUT THNH PH NHA TRANG ................................................................... 53
2.1. Phng n lp t h thng s dng nhin liu thay th cho ng cdiesel D6BR trn xe but thnh ph Nha Trang. ................................................53
2.1.1. H thng s dng nhin liu thay th n .............................................53
2.1.2 H thng s dng nhin liu thay th v diesel song song......................53
2.1.3 La chn gii php. ...............................................................................54
2.2 Gii php k thut ng c c th s dng nhin liu Biodiesel. .............54
2.2.1 Bnh sy s dng nc lm mt lm nng nhin liu ........................56
2.2.2 Bnh sy s dng ngun in mt chiu.................................................58
2.2.3 Bnh sy tn dng ngun nhit kh x ....................................................592.2.4 La chn ...............................................................................................60
2.2.5 S tng th h thng nhin liu s dng Biodiesel v Diesel song
song (H. 2-6 ) .................................................................................................60
2.3 Gii php k thut ng c c th s dng nhin liu LPG......................61
2.3.1 Gii php k thut ng c c th s dng LPG v diesel song
song................................................................................................................61
2.3.1.1 Gii php k thut h thng nhin liu diesel c kh nng phun
mi .............................................................................................................61
2.3.1.2 Gii php k thut lp t h thng cung cp LPG trn ng c......72
2.3.1.3 Gii php k thut lp t c cu hn ch tc ng c................88
2.3.2 S tng th h thng nhin liu LPG v Diesel song song.................93
CHNG 3. KT LUN V XUT KIN .................................................. 95
3.1 Kt lun. ......................................................................................................95
3.2 xut kin. .............................................................................................96
TI LIU THAM KHO ............................................................................................ 98
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LI NI U
Cng vi s pht trin mnh m ca nn kinh t, i sng nhn dn ngy
mt nng cao c v vt cht ln tinh thn. Song bn cnh t nc ta cng phi
i mt vi nhiu kh khn nh nhng nn kinh t ang pht trin khc, c bit l
vn nhim mi trng. Nhiu nh my, x nghip mc ln phc v i hi ca
qu trnh pht trin, ng thi x vo bu kh quyn mt lng kh thi khng nh.
i sng ngi dn c ci thin, kh nng mua sm cc vt dng t tin nh
t, xe mynm trong tm tay ca nhiu gia nh. Mt phng tin tham gia
giao thng ngy mt cao, bn cnh l s thiu ng b trong qu trnh quy hochgiao thng, vic qun l cht lng cc phng tin tham gia giao thng cn bung
lng. Nhng vn ny ang lm cho lng kh thi ca nghnh giao thng vn ti,
c bit trong lnh vc giao thng ng b x vo kh quyn ngy mt tng nhanh.
gii quyt vn ny cn phi c nhng chin lc di hn pht trin cc
phng tin giao thng cng cng nh ng st, tu in ngm, mng li xe
but,tm kim cc gii php k thut nhm nng cao qu trnh chy nhin liu v
s l kh thi, s dng cc phng tin dng nhin liu sch thay cho cc loi xedng nhin liu truyn thng xng, du nh hin nay.
i t m ngun nhin liu mi sch hn thay th cho nhin liu truyn thng
hin ang s dng khng ch gp phn lm gim nng cc cht c hi trong kh
thi, bn cnh n cn gp phn a dng ho cc ngun nhin liu, y li nguy
c cn kit ngun nhin liu truyn thng.
Thnh Ph Nha Trang cng nh cc thnh ph khc trong c nc, vn
gia tng cc phng tin giao thng c nhn nh t, xe my, nhim mi trng
ang lm au u cc nh qun l. c bit vi hng pht trin ca thnh ph l
tr thnh mt thnh ph du lch th vic kim sot cc cht c hi trong kh quyn
c mt bu khng kh trong lnh l vn sng cn. M rng mng li giao
thng cng cng c bit l i ng xe but, khuyn khch ngi dn gim bt
phng tin c nhn, s dng cc loi xe dng nhin liu sch.
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Hin nay trn th gii k thut chuyni xe dng nhin liu truyn thng
(xng, diesel) sang dng nhin liu thay th (LPG, Biodiesel, NGV, LNG) t
c nhiu thnh tu, c bit l k thut chuyn i ng c diesel sang dngnhin liu LPG c nhng bct ph mi. ng csau khi chuyni t thay i
kt cu ban u, gi thnh chuyn i r nhng vn p ng tt cc yu cu k
thut
Vi suy ngh t m kim ngun nhin liu mi thay th nhin liu truyn
thng, nhm lm cho mi trng thnh ph Nha Trang sch hn. Khuyn khch,
tuyn truyn ngi dn thnh ph ng h vic s dng nhin liu sch cho cc
phng tin c nhn ca m nh. T m rng m h nh pht trin rng ri trn c
nc. c s hng dn ca thy Phng Minh Lc, em xin ng gp mt phn
nh tng trn sm thnh hin thc vi ti: Nghin cu kh nng s
dng nhin liu thay th cho i xe but thnh ph Nha Trang.
Ni dung ca ti gm 3 chng:
Chng 1: Tng quan.
Chng 2: Kh nng s dng nhin liu thay th cho i xe but thnh phNha Trang.
Chng 3: Kt lun v sut kin.
Sau hn 3 thng n lc c gng, c s hng dn, gip tn t nh ca
thy Phng Minh Lc, Cng ty c phn t in my Nha Trang, qu thy c trong
Khoa C Kh, bn b trong qu trnh tm kim ti liu, ng gp kin. Em c
bn hon thnh ni dung v trnh by trong lun vn ny.
Do trnh v thi gian c hn, mt khc v y l ln u tin thc hin
c lp mt cng tr nh mang tnh cht nghin cu khoa hc nn khng th trnh
khi nhng thiu st. Em rt mong nhn c s thng cm, ch dy, gp ca qu
thy c v bn b b sung cho ti ny c hon thin hn.
Em xin chn thnh cm n.
Nha Trang, ngy 20 thng 11 nm 2007
SVTH: Ng Quang Tun
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CHNG 1. TNG QUAN
1.1.Nhin liu thay th
1.1.1 Cc ch tiu k thut ca nhin liu Diesel.
Cc ch tiu k thut quan trng nht ca nhin liu diesel bao gm: nhit tr,
tnh t bc chy,hm lng tp cht v nht.
1.1.1.1 Nhit tr
Nhit tr (H) l lng nhit nng to ra khi t chy hon ton mt n v
khi lng hoc mt n v th tch nhin liu. nhit tr ca nhin liu lng v rn
thng tnh bng kJ/kg, ca nhin liu kh-kJ/m
3
hoc kJ/kmol. Anh v M, nhittr c tnh bng n v Btu/lb ( British thermal unit/pound ) hoc Btu/ft3 ( British
thermal unit/foot3 ).
Nhit tr l mt ch tiu cht lng c bn ca tt c cc loi nhin liu .
nhit tr c th c xc nh bng nhit lng k ng tch (nhit lng k kiu
bom) hoc nhit lng k ng p bng cch t chy mt lng xc nh mu th
ri o nhit lng to ra v tnh ton nhit tr. Khi tnh ton, chng ta thng ly
nhit tr t cc bng s liu c sn. trnh nhm ln, cn phn bit cc khi nimnhit tr di y:
Nhit tr ng p (Hp)- Nhit lng thu c khi t chy hon ton mt
n v s lng nhin liu sau khi lm lnh sn phm chy n nhit bng nhit
ca hn hp trc lc t chy trong iu kin p sut ca sn phm chy
c lm lnh bng p sut ca kh hn hp trc lc t chy.
Phng trnh cn bng nng lng nhit lng k ng p:
Ec + Uf+ p.Vf + Ua + p.Va = Up + p.Vp + Hp
hoc Ec + Um + p.Vm = Up + p.Vp +Hp
Ec = (Hp + Ip Im)T
Nhit tr ng tch (HV)- nhit lng thu c khi t chy hon ton mt
n v s lng nhin liu sau khi lm lnh sn phm chy n nhit bng
nhit ca hn hp trc lc t chy trong iu kin khng thay i th tch ca
sn phm chy v hn hp kh trc lc t chy.
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Phng trnh cn bng nng lng nhit k ng tch :
Ec + Um = Up + HV
Ec =(HV + Up Um)T
Ec- ho nng ca nhin liu
Uf, Ua, Um, Up - ni nng ca nhin liu, khng kh, hn hp chy v sn
phm chy, tng ng,
Im, Ip enthalpy ca hn hp chy v sn phm chy,
Hp, HV- nhit tr ng p v nhit tr ng tch.
Nhit tr ng p c ngha thc t trong tnh ton cc thit b ng lc, v
sn phm chy thng c thi ra kh quyn c p sut v nhit bng p sut
v nhit ca nhin liu v khng kh trc lc i vo thit b. V vy, nu trong
cc bang s liu cho nhit tr ng tch hoc nu xc nh nhit tr bng nhit lng
k ng tch th phi i sang nhit tr ng p. C th s dng cng thc sau y:
Hp = Hv + 10-3 pm(Vm Vp)
Trong : Hp, Hv - nhit tr ng p v nhit ng tch, [kJ/kg],
Pm- p sut ca hn hp trc khi t chy, [N/m2
]Vm, Vp- th tch ca hn hp trc lc t chy v ca sn phm chy
c lm lnh p sut pmng vi 1 n v s lng nhin liu.
i vi nhin liu lng gc du m: Hv H02,1 .
Nhit tr cao (Hc)- nhit lng thu c khi t chy hon ton mt n v s
lng nhin liu, bao gm c lng nhit to ra do s ngng t ca hi nc c
trong sn phm chy khi ta lm lnh n n nhit bng nhit ban u.
Nhit tr thp(HT)- nhit lng thu c trong trng hp nc c trong sn
phm chy vn trng thi hi. Nh vy nhit tr thp nh hn nhit tr cao mt
lng bng nhit n ho hi ca nc c trong sn phm chy.
-i vi nhin liu lng:
HT = HC r.(9h + w)Trong : HT, HC - nhit tr thp v nhit tr cao, [kJ/kg],
r- nhit n ho hi ca 1 kg nc, r =2.512 kJ/kg
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9h- lng hi nc c hnh thnh khi t chy h kg hydrogen c trong 1
kg nhin liu,
w- lng nc c trong 1 kg nhin liu.1.1.1.2 nht
nht- cn gi l ma st ni, l mt tnh cht ca cht lng c trng cho
lc ma st chng li s chuyn dch tng i ca cc lp cht lng cnh nhau di
tc dng ca ngoi lc.
nht ca nhin liu diesel c nh hng ch yu n cht lng qu trnh
phun nhin liu. nht qu cao lm cho cc tia nhin liu kh phn tn thnh cc
ht nh v c th bm trn thnh xylanh. Ngc li, nht qu thp li lm cho
cc tia nhin liu qu ngn, khng bao trm ht khng gian ca bung t. C hai
trng hp trn u dn n cht lng qu trnh to hn hp chy khng cao, lm
tng lng nhin liu chy rt v chy khng hon ton. Ngoi ra, nht ca
nhin liu qu thp c th nh hng xu n cht lng nh lng ca h thng
phun do lm tng mc r r ti cc cp siu chnh xc ca bm cao p v vi
phun, ng thi tng mc mi mn ca cc chi tit chuyn ng thuc h thngnhin liu .
Mc d khng phi l mt ch tiu k thut c nh hng quyt nh n
cht lng hot ng ca ng c, nhng ngi ta thng cn c vo nht
phn loi du diesel nng.S d nh vy l v:
- nht ln l mt i lng d xc nh.
- nht c lin quan n nhiu tnh cht khc ca du diesel. V d: nu
nhin liu nng c nht di 3500 sec Redwood, th s cetane thng cao hn
25 v lng tp cht cng thng thp hn mc quy nh.
1.1.1.3 Tnh t bc chy
Tnh t bc chy ca nhin liu l tnh cht lin quan n kh nng t pht
ho khi hn hp nhin liu khng kh chu tc dng ca p sut v nhit
ln.
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nh lng tnh t bc chy ca nhin liu, c th s dng cc i lng
di y:
Thi gian chm chy(ti)- Nhin liu c tnh t bc chy cng cao th thi
gian chm chy cng ngn, v ngc li. Thi gian chm chy l i lng phn
nh tnh t bc chy ca nhin liu diesel theo cch m chng ta mong mun nht,
bi v n c nh hng mnh v trc tip n ton b din bin v cht lng ca
qu trnh chy ng c diesel. Tuy nhin, thi gian chm chy ca nhin liu
diesel ng c thc t ch ko di t vi phn vn n vi phn ngn mt giy. o
trc tip mt khong thi gian ngn nh vy l mt vic rt kh, cho nn ngi ta
s dng mt s i lng khc nh gi tnh t bc chy trn c s mt s
tnh cht l-ho ca nhin liu c lin quan mt thit vi thi gian chm chy, hoc
so snh tnh t bc chy ca mu th v nhin liu chun.
Hng s nht-t trng ( Viscosity Gravity Number VG ) l mt thng
s c tnh ton trn c s nht v t trng ca du diesel. Tu thuc vo n
v ca nht, n v ca t trng v quan im ca tc gi, cng thc tnh c
nhng dng khc nhau. Ch s diesel ( Diesel Index DI ) l thng s c tnh ton trn c st
trng v im aniline ca nhin liu
Bi v nht, t trng v im aniline u l nhng i lng c quan h
cht ch vi thnh phn ho hc ca du diesel xt t hm lng cc nhm
hydrocarbon, nn hng s nht-t trng v ch s diesel s phn nh tnh t bc
chy ca nhin liu. Hng s nht-t trng cng nh th thi gian chm chy
cng ngn, tnh t bc chy cng cao; cn ch s diesel cng nh th thi gian chm
chy cng di.
S cetane- ( Cetane Number CN ) l i lng nh gi tnh t bc chy
ca nhin liu bng cch so snh vi nhin liu chun. V tr s, l s phn trm
th tch ca cht n-cetane (C6H34) c trong hn hp vi cht aphthalenmethy ln
(C10H7CH3) nu hn hp ny tng ng vi nhin liu th nghim v tnh t bc
chy.
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Phng php xc nh s cetane c p dng ph bin hin nay l so snh
t s nn ti hn ( t s nn ti hn l t s nn, ti nhin liu s pht ho) ca
nhin liu th nghim v ca nhin liu chun trn mt loi ng c tiu chun hohot ng mt ch quy c.
Nhin liu chun l hn hp vi nhng t l th tch khc nhau ca n-C16H34
v 3710 CHHC .n-C16H34l mt hydrocarbon loi parafin thng c tnh t bc
chy rt cao, ngi ta quy c s cetane ca n bng 100; cn 3710 CHHC l
mt hydrocarbon thm, cha mt nhm methyl trn ln vi cc nguyn t
hydrogen , kh t bc chy, c s cetane quy c bng 0.
1.1.1.4 Hm lng tp cht
Du diesel, c bit l du cn, thng cha mt lng ng k tp cht c
ngun gc t du m(v d:S, V, Na, P, ) hoc t mi trng thm nhp vo
trong qu trnh ch bin,vn chuyn, bo qun v phn phi (v d: nc, t,
ct,).
Tp cht c hc- Tp cht c hc trong nhin liu c nh hng n h
thng phun nhin liu ca ng c diesel mt cch trc tip v nghim trng hn sovi trng hp ca ng c xng.Trong h thng phun nhin liu ca ng c
diesel c nhng chi tit c ch to vi chnh xc rt cao, nh cp piston-
xylanh ca bm cao p v u phun ca vi phun. Khe h gia cc cp chi tit ni
trn c tr s trung bnh khong 0,003 mm v s c mt ca vt cng vi kch thc
vi phn ngn mm cng c th lm h thng phun nhin liu b h hng rt nhanh.
Chnh v vy, h thng lc nhin liu ca ng c diesel thng phc tp hn ng
thi vic bo tr chng cng c nhng yu cu kht khe hn. i vi du cn c
nht v hm lng tp cht c hc cao, ng c cn phi c trang b h thng x
l nhin liu c chc nng sy nng v loi b nhng tp cht c kch thc ln
trc khi nhin liu c a n cc b lc thng dng.
Lu hunh(S)- S c trong nhin liu tn ti di dng t do hoc hp cht,
nh mercaptan, sulffide,vv. D tn ti dng no, S u c tc ng n mn
nhng mc khc nhau.
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- Mercaptan c kh nng tc dng ln nhiu loai kim loai, nh ng (cu),
km(zn), cadmum(cd), v s to thnh cc hp cht ho hc phc tp, kh tan. Cc
hp cht ny c th kt ta trn cc chi tit ca h thng nhin liu lm nh hng
xu n hot ng ca ng c.
- Lu hunh t do(S) s c t chy thnh SO2. Mt phn SO2 b oxy ho
thnh SO3 di tc dng xc tc ca oxyt st(Fe2O3) v mt s cht khc c trong
nhin liu. Sau , SO3 kt hp vi hi nc to thnh axit phosphoric(H2SO4)
theo cc phn ng:
S + O2
SO2
2SO2+ O2 2SO3
SO3 + H2O H2SO4
Trong iu kin nhit cao, axit phosphoric tn ti trng thi hi cng
vi hi nc v cc cht khc ca kh thi. Khi nhit ca kh thi gim xung,
hi axit c th ngng t v c tc ng n mn mnh
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1.1.2 Nhin liu biodiesel
1.1.2.1 Khi nim
Biodisel l nhng mono ankyl ester, n l sn phm ca qu tr nh ester haca cc axt hu c c nhiu trong du m ng thc vt. N l nhin liu c th
thay th cho du diesel truyn thng, s dng trong ng c t trong.
Di tc dng ca cht xc tc, du thc vt + methanol hoc ethanol cho
sn phm ester + glycerine + axit bo (ester ha du thc vt bng ethanol kh hn
bng methanol).
V d: 1.05 tn du ci + 0.11 tn methanol cho ra 1 tn ester + 0.1 tn
glycerine + 0.025 tn axit bo.
Thng thng biodiesel c s dng dng nguyn cht hay dng hn hp
vi du diesel. V d nh B20 l hn hp gm 20% biodiesel v 80% diesel c
ngun gc du m.
H. 1-1. Xe but s dng nhin liu biodiesel (u nnh).
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H. 1-2. Biodiesel th nghim trn t M
1.1.2.2 Tnh hnh sn xut v s dng Diesel sinh hc t du thc vt
1.1.2.2.1 Tnh hnh th gii:
Vn s dng du thc vt lm nhin liu cho ng c diesel c
chnh Rudolf Diesel- ngi pht minh ra loi ng c ny dng t cch y hn
mt trm nm (du lc). Sau y, nhin liu ha thch qu nhiu v r nn ngi ta
lng qun n, nhng t nhng nm 80 ca th k trc tr li y, du m c
du hiu cn kit, gi c tng chng mt buc th gii phi t li vn ny. i
tin phong c l phi k n ngi c, nm 1988, cc cng ty ho cht ca c
tinh luyn loi du diesel sinh hc t ht Ci du, loidu ny khng nhng githnh thp, m cn c th trng c nguyn liu, m bo chy ht, hm lng
cc-bon ca kh thi -t thp hn 50% so vi du diesel truyn thng . Hin nay,
15% trm xng ca c c cung cp du diesel sinh hc, n tr thnh ngun
nhin liu chnh cho cc xe ch hng ng di v xe but. Hng Shell trong nm
nay cng c k hoch u t 400 triu Euro vo min Bc nc c xy
dng thm mt nh my sn xut loi sn phm ny, d kin n nm 2008, sn
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lng s t ti 200 triu lt. Ngoi ra cc nc trng nhiu cy c du cng vo
cuc: Hn quc s bn du diesel sinh hc (biodiesel) cho cc phng tin t nhn
t thng 7/2006. Loi biodiesel ny gm diesel v 5% du ht Ci. Hn quc angcn nhc s dng loi biodiesel cha 20% du ht Ci trong tng lai; Malaixia l
nc ng u th gii v sn xut du C, vi sn lng 13,9 triu tn (nm
2004), ch bin du diesel sinh hc t ngun nguyn liu di do ny s gp phn
p ng nhu cu nhin liu trong nc v xut khu; Nht bn v Indonnesia: Mt
d n c quan tm nht l vic pht trin nhin liu biodiesel (du diesel sinh
hc) s dng cy c dujarak ( Jatropha curcas L) vn rt ph bin
Indonesia.Hin Indonesia c hng nghn hcta t c th dng pht trin loi
nng lng xanh ny; Trung quc: n 2010 sn xut 1triu tn, nm 2020 s sn
xut 9 triu tn du diesel sinh hc t cy Hong lin v cy ay. 1.1.2.2.2 Tnh hnh trong nc :
Theo ngh ca B Cng nghip v Vn phng Cng ty Sojitz ti H Ni,
ngy 03 thng 8 nm 2005, B Ti nguyn v Mi trng, vi t cch l C quan
u mi ca Chnh ph Vit Nam tham gia v thc hin Ngh nh th Kyoto xc nhn PIN pht trin du Da diesel sinh hc theo CDM ti tnh Bnh nh.
Nhm nghin cu do PGS.TS H Sn Lm - phn vin trng Phn vin
Khoa hc vt liu TP.HCM thuc Vin Khoa hc v cng ngh VN - ch tr khng
nh c kh nng nghin cu sn xut du diesel sinh hc (biodiesel) t du thc
vt ca Vit nam. PGS.TS H Sn Lm cho bit nhm nghin cu hp tc vi
Vin Ha k thut H Tng hp Jena (c) phn tch thnh phn, tnh cht cc
mu du diesel sinh hc do nhm iu ch. Kt qu cho thy cc mu du diesel
sinh hc t du thc vt VN t tiu chun chu u v biodiesel.
T thng 8/2006, h thng thit b sn xut nhin liu diesel sinh hc
(biodiesel) t du n ph thi vi cng sut 2 tn/ngy s c trin khai ti cng ty
Ph Xng, qun Th c, TP.HCM. D n sn xut du biodiesel t du n ph
thi ti TP.HCM c ngun vn u t khong 9,69 t ng, trong c 1,5 t ng
vay t ngun vn ngn sch Nh nc.
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1.1.2.3 c tnh ca biodiesel
Tnh cht vt l ca biodiesel tng t nh diesel nhng tt hn diesel v
mt cht thi.Biodiesel khc phc c nhng nhc im ca du thc vt nh nht
qu ln (cao gp 6 14 ln diesel), ch s Cetan thp, d b trng hp.
Cc loi biodiesel u c t l % trng lng oxy kh ln, y l iu m du
diesel khng c.
Bng 1-1.Tnh cht l ha c bn ca mt s biodiesel [ 7 ]
ESTER
Khilngring
(g/cm3)
nht( 200C)( cSt )
imc(0C)
imchp la
(0C)
Nhit tr (MJ/kg)(kCal/kg)
Metyl du ci 0.88 7.09 -5 171 37.70 (9020)
Oleate ca methylk thut
0.88 7.4 -14 37.37 (8940)
Methyl du da 0.886 5.3 -2 93 37.83 (9050)
Du diesel 0.836 5.3 -2 40 43.80 (10478)
Bng 1-2. Hm lng cn v ch s Cetan ca mt s cht [ 7 ]
ESTER Cn Ch s Cetan
Metyl du ci 1.2 43
Oleate ca methyl k thut 0.8 54
Methyl du da 0.7 43Du diesel
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Bng 1-3. So snh mt s tnh cht vt l ca hn hp nhin liu ester du ci ha
vi diesel cc t l % khc nhau [ 7 ]
Ch tiu Diesel B20 B30 B40 B50 B75 B100
Ch s Cetan 52.0 52.0 52.4 52.8 53.2 54.1 54.1
Khi lng ring
(g/cm3)0.840 0.846 0.851 0.856 0.861 0.873 0.884
nht
(mm2/s)4.8 4.9 5.2 5.5 5.8 6.4 13.1
im nng ch(0C)
-9 -9 -9 -9 -9 -9 -12
im c
(0C)-6 -6 -5 -5 -5 -5 -5
%O2 theo
khi lng0.00 2.35 3.30 4.60 5.95 8.86 10.70
Nhit tr
(kJ/kg)43800 41983 41443 40903 40600 38664 37370
1.1.2.4 Qu trnh iu ch biodiesel.Nhin liu biodiesel c lm t du thc vt, m ng vt cn mi hay
qua s dng. Nguyn tc ca qu tr nh: du m tc dng vi cn methanol hoc
ethanol to ra ester. Cc ester ny chnh l biodiesel. Sn phm ph ca qu trnh
ny l glycerin s dng trong ngnh dc v m phm.
Hin nay biodiesel c sn xut t qu tr nh chuyn ha ester. Du thc
vt, m ng vt sau khi lc c thy phn trong mi trng kim tch axit bo
t do. Sau uc trn vi cn (thng l methanol) v cht xc tc Natri hay KaliHidroxit triglyceride phn ng to ra ester v glycerin. Cui cng l giai on
tch v lm sch.
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Cc phn ng ha hc:
2 1
OH2
2 3
CH COOR
|CHCOOR|CH COOR
2
2
CH OH
|CHOH|CH OH
+
1
2
3
R COOH
R COOH
R COOH
NaOH(KOH)3 3RCOOH CH OH RCOOCH
RCOOCH3 c gi l biodiesel.
S sn xut biodiesel:
T nhng iu trnh by trn ta thy biodiesel c cc c tnh gn ging nh
diesel, thch hp s dng trn ng c t trong v vic t m kim loi du thc vt
p ng c tiu chun lm nhin liu cho ng c t trong, khng cnh tranh
Du m
Thy phntrongmi trng kim
Este ho bng methanolhoc ethanol
Tch
Lm sch
Biodiesel
Lc
Cht xc tc
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vi thc phm, c thu li c cao l iu rt cn lm. Trong cc loi cy ly du
c chit sut ln v c sn lng phong ph, thch hp vi iu kin kh hu min
nam nc ta phi k n cy da. V cy da chng ta cha c mt iu tra c bny nhng ng v mt k thut th n l mt ngun nhin liu tt cho ng c
t trong: nhit tr cao, nht thp nht trong cc loi du thc vt, ch s Cetan
cao gn bng diesel, l nhin liu linh ng c th pha vi diesel bt c t l no. .
. Do n l mt trong nhng ng c vin sng gi cho vic nghin cu v ch
bin lm nhin liu biodiesel cho ng c t trong. Mt khc theo gio s Chu
Phm Ngc Sn th cy c du (c tnh cht gn nh cy da) l mt cy cng
nghip rt ng lu , sn lng cao hn da nhiu, khong 3.5 tn/ha, thu li trn
mi hecta l 2505 la. Vic nghin cu tt cy da lm nhin liu cho ng c s
to iu kin cho vic nghin cu cy c du.
1.1.3 Nhin liu LPG (Liquefied Petroleum Gases)
1.1.3.1 Khi nim LPG
Nhin liu kh ho lng(LPG:kh du m ho lng) c thnh phn c bn l
propane (C3H8) v butane (C4H10), ngoi ra kh ho lng cn cha mt lng nhcc hydrocarbon khc nh: ethane (C2H6), pentane (C5H10), ethylene (C2H4),
propylene (C3H6), buthylene (C4H8) v cc ng phn (isomer) ca chng.
Loi nhin liu ny c pht trin v thng mi ho t nhng nm 1950.
My thp k qua chng c dng ch yu cho cng nghip nh cng nghip thu
tinh, gm v sinh nhit gia dng. Kh ho lng cn c phn tch thnh cc cu
t ring bit lm nguyn liu cho nhiu ngnh cng nghip khc nh sn xut
cao su nhn to, vt liu tng hp, phm mu, dc liu, v.v . Vic nghin cu s
dng chng cho ng c t trong trn phng tin giao thng vn ti bt u
trong nhng nm gn y.Tuy vic p dng loi nhin liu trn t cn nhng thit
b cng knh hn nhin liu lng nhng n cho php gim c mc pht
nhim v chnh l im m cc nh ch to t quan tm nht hin nay. Khi s
dng chy ng c t, kh ho lng thng c cha trong b nh di p sut
khong 16 bar.
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1.1.3.2 Tr lng LPG v th trng tiu th
L sn phm trung gian gia kh thin nhin v du th, nhin liu kh ho
lng c th thu c t cng on lc du hoc lm tinh khit kh thin nhin. Vvy, ngun gc kh ho lng ph thuc vo xut x nhin liu. Ni chung trn th
gii c khong 40% LPG thu c t qu trnh lc du th.
Sn lng kh ho lng trn th gii nm 1995 l 130 triu tn, chim 2%
tng nng lng tiu th di cc dng khc nhau. Ngi ta d kin trong nhng
nm u ca th k 21, tng sn lng LPG trn th gii s t khong 200 triu
tn/nm
Bng 1-4. Sn lng v tiu th kh ho lng ti chu [ 5 ]
( n v tnh: 1000 tn. Theo Asia LPG Seminar organized by
LPG Center of Japan, Tokyo 2/1998 )
1996 2000 2010Nc Sn
lngTiu th
Snlng
Tiu th Sn lng Tiu th
Indonesia 3228 715 3432 1154 2400 2886
China - 5758 - 9000 - 27000
Japan 4537 19710 4686 19959 4520 21600
Korea 1461 5761 2300 6323 2803 9448
Malaysia 1499 1392 3435 2226 3521 3718
Philippines 429 811 601 1414 1359 3497
Taiwan 700 1410 1130 1500 1750 1800
Thailand 1959 1829 2979 2240 3755 3531
India 3356 4198 3805 8439 10000 15000
Vietnam 0 86 340 224 840 527
Phn ln lng kh ho lng thu c hin nay c s dng lm ngun cht
t sinh nhit gia dng hay cng nghip. Lng kh ho lng lm nhin liu cho
t ng trng hin ch chim mt t l khim tn: 1% Php, 3% M, 8%
Nht
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Tuy nhin mt s nc c chnh sch khuyn khch s dng LPG lm
nhin liu cho t nhm mc ch gim nhim mi trng th t l ny rt ng
k, chng hn nh H Lan, (42%)Cc s liu trn cha k nhng ng c trncc t chuyn dng s dng LPG( chng hn t chy trong sn bay, xe nng
chuyn , my mc nng nghip).
T l tiu th LPG vi nc tiu biu:
Php: Nhin liu(1%); Cng nghip(15%); Nng nghip(17%); Gia
dng(67%)
H Lan: Nhin liu(42%); Cng nghip(24%); Nng nghip(14%); Gia
dng(20%)
S pht trin t dng LPG ph thuc vo ch trng ca mi quc gia, c
bit l ph thuc vo chnh sch bo v mi trng. S khuyn khch s dng t
LPG th hin qua chnh sch thu u i ca mi quc gia i vi loi nhin liu
ny.
T l t s dng LPG mt s nc nh: H Lan(8,7%); Hn Quc(7,6%);
(4,4%); Nht(0,7%); M(0,4%); Php(0,1%). mt s nc Chu , Hn Quc v Nht Bn chng hn. gim nhim
mi trng th, chnh ph cc nc ny khuyn khch, tin ti buc taxi phi
dng nhin liu kh ha lng. Hin nay ton b taxi Hn Quc u dng loi nhin
liu ny. [2 ]
1.1.3.3 c tnh nhin liu kh ha lng
1.1.3.3.1 Thnh phn ho hc
Theo tiu chun Chu u, nhin liu kh ha lng phi c t 19 n 50%
hydrocabure C3 ( propane v propylene). Chu , thnh phn nhin liu kh ha
lng kh n nh, cha ch yu l hydrocarbure C4, chng hn nh Hn Quc ch
c butane l kh ha lng c s dng chnh thc. Ngc li M th ch c
hydrocarbure C3 c s dng.
Hin nay trn th trng nc ta c sn phm LPG ca nhiu cng ty kinh
doanh khc nhau, thnh phn ca propane v butane trong hn hp cng khc nhau:
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LPG ca Elf Gas Si Gn c t l Propane / Butane l 20/80, ca Petrolimex l
30/70, ca Si Gn Petro l 50/50.
Nht, cung cp cho dn c LPG di dng 100% Propane v thi tit lnh,Propane d bc hi hn Butane, cn cung cp cho cng nghip di dng 100%
Butane v d vn chuyn, tn cha v trong iu kin sn xut d trang b cc thit
b u un nng LPG bc hi hon ton khi s dng.
Bng 1-5. c tnh l ho ca cc loi LPG thng phm.
Loi LPG
c tnh 100% Propane(Propa Gas) 100% Butane(Buta Gas)
Hn hp Butane Propane 50/50(Sai Gn Petro)
T trng [ g/cm3 ] (150C) 0,507 0,580 0,541
p sut hi [ kg/cm2 ] (400C) 13,5 3,2 9,2
Thnh phn:C2 (Etane)C3 (Propane)C4 (Butane)C5 (Pentane)
1,796,21,50,0
0,00,4
99,40,2
0,051,547,51,0
Nhit chy [ kcal/kg] 11.070 10.920 10.980
Nhit lng to ra khi t chy (nhit chy) ca Propane 11.070 kcal/kg,
trong khi Butane l 10.920 kcal/kg. Mt khc p sut hi to ra 200C ca
Propane l 13,5kG/cm2, ca butane l 3,2kG/cm2. Qua ta thy LPG cng nhiu
Propane th nhit chy c cao hn mt t v s dng c trit v bc hi hon
ton nhit mi trng. Ngc li, LPG c nhiu Butane th bnh cha khng
cn c p lc cao v p sut hi khng ln nhit mi trng nhng khng s
dng c trit nu nhit mi trng thp. Ni chung, LPG c th c thnh
phn Propane v Butane khc nhau, nhng cht lng ca LPG khng c g khc
nhau ng k.
Cng cn nhn mnh thm rng, nhin liu kh ha lng cha rt t lu
hunh. Thng n ch cha t 40 60ppm, thp hn rt nhiu so vi tiu chun
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Cng ng Chu u(200ppm). Do , ng c dng LPG pht rt t cc cht
nhim gc lu hunh v hiu qu ca b lc xc tc c ci thin.
1.1.3.3.2 L tnhNhin liu kh ha lng c nhit tr ring theo khi lng (PCIm) cao, cao
hn c xng hay du diesel. Tuy nhin do khi lng ring ca n thp, nhit tr
ring theo th tch (PCI) thp hn nhin liu lng.
LPG c th c ho lng nhit bnh thng bng cch gia tng p sut
va phi hoc p sut b nh thng bng cch s dng k thut lm lnh lm
gim nhit .
Bng 1-6. So snh LPG v cc loi nhin liu c in [ 2 ]
H. 1-3. So snh th tch cha nhin liu ca cc loi nhin liu khc nhau
cho cng tng s nng lng pht ra
Thng s c trng Eurosuper DieselPropane
thng miButane
thng miLPG
Khi lng ring(kg/dm3)
0,725-0,780 0,820-0,860 0,51 0,58 0,51-0,58
Nhit tr thp PCI
-theo khi lng(MJ/kg) 42,7 42,6 46,0 45,6 45,8
-theo th tch(MJ/dm3)
32,0 35,8 23,5 26,4 25,0
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Bng 1-7. So snh LPG vi xng, du diesel [ 11 ]
(Theo Bch Khoa Ton th M Wikipedia )
1.1.3.3.3 Ch s Octane
Nhin liu kh ha lng c c trng bi ch s octane nghin cu (RON)
cao, c th d dng t n 98.
Trong thc t, ngi ta xc nh ch s octane (Octane Number ON) cahn hp kh ho lng bng cng thc:
ONhh = V1.ON1 + V2.ON2 ++ Vn.ONn
Trong :
ON1,ON2,ONn l s octane ca hp phn ring bit ca hn hp.
V1, V2,,Vn l % th tch ca cc hp phn ring bit.
Bng di gii thiu RON ca cc loi kh khc nhau. Ch s octane ng c
(MON) ca LPG cng cao hn xng.
Bng 1-8. Ch s octane ca mt s cht
Cht RON MON
PropanePropenen-ButaneIsobutaneButene1
Butene2
>100102
95>100(98)
100
10085929980
83
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Ng Quang Tun 44DLOT n tt nghip
1.1.3.3.4 Ch tiu cht lng ca LPG
Bng 1-9. Ch tiu cht lng LPG ca PETROLIMEX [ 5 ]
Ch tiu cht lng Mc qui nh Phng php th
1. t khi-d4
15 max
d@600F max
0,5531
0,5533
ASTM D.1657
2. p xut hi bo ho 37,8 0C, [kPa] 480-820 ASTM D2598
3.Thnh phn, [ % mol]
-Ethane
-Propane
-Butane
0.2 - 1.0
30 - 40
60 - 70
ASTM D.2163
4. Nhit tr, [kcal/kg] 40000 - 55000 ASTM D.2598
5. Hm lng sulphur, [ppm] max 170 ASTM D.2784
6. Hm lng hydrogen sulfide, [ppm] Negative ASTM D.2420
7. Nc t do Khng
8. n mn ng 37,8 0C No.1 ASTM D.1838
Bng 1-10. LPG ca Nga theo tiu chun 2044-75 [ 5 ]
Ch tiu Mc qui nh
1.Thnh phn-Tng lng hydrocarbon c C 2, max
-Tng lng propane, propylene,max/min-Tng lng butane v butylene, max/min
475/-
-/20
634/-
-/60
6-/34
60/-
2. Phn lng ( C5 ) 200C, [%vol] 1 2 2
3. p sut hi bo ho 45/-200C, [kgf/cm2 ], max 16/1,6 16/- 16/-4. Hm lng H2S, [g /100m
3 kh ] 0,015 0,015 0,015
5. Hm lng lu hunh tng , [%wt] 5 5 5
6. Hm lng nhn bit mi trong khng kh, [% vol] 0,5 0,4 0,3
7. Nc t do v kim Khng Khng Khng
- Hn hp propane butane k thut ma ng
- Hn hp propane butane k thut ma h
- Butane k thut
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1.2.ng dng nhin liu thay th cho ng cdiesel xe but Thnh Ph Nha
Trang
1.2.1 Gii thiu chung v xe but Thnh Ph Nha Trang1.2.1.1 S lc v xe but Thnh Ph Nha Trang
Xe but Thnh Ph Nha Trang do Vit Nam v Hn Quc sn xut. ng
c v gm xe l ca hng Huyndai-Hn Quc sn xut, phn cn li do Cng Ty
t 1-5 sn xut.
Xe but l loi xe khch c chung nhn hiu Transinco, chng gp phn rt
quan trng vo vic vn chuyn hnh khch i li trong Thnh Ph Nha Trang v
cc vng ven thnh ph. Xe but gp phn gim lu lng cc phng tin c nhn
lu thng trong thnh ph t lm gim nhim, tai nn, n tc giao thng, to v
p vn minh cho th.
Xe but Thnh Ph Nha Trang mang tnh hin i, an ton, thm m . Xe
c tnh nng ng lc hc cao, tc chung bnh cao, khi ng d dng, h thng
phanh, h thng li hin i, tnh an ton cao. Vt liu ch to cc chi tit c bn,
chng mn, chng g tt, ph hp vi kh hu bin ca thnh ph. v xe c kt cuv mu sc p to v p m quan cho th
H. 1-4. Xe but Nha Trang phc v ch khch
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1.2.1.2 Thng s k thut ca xe but Thnh Ph Nha Trang
1.2.1.2.1 Loi, Kch thc v trng lng ca xe but
Th t Tn gi n v Thng s v c tnh
(1) (2) (3) (4)
1 Loi t Khch, c trung
2 Chiu di tng th mm 8480
3 Chiu rng tng th mm 2290
4 Chiu cao tng th mm 3015
5 Khong cch trc trc mm 1910
6 Khong cch trc sau mm 1740
7 Vt bnh c s mm 4000
8 Trng lng tnh kg 5950
9 Trng lng ton ti kg 7875
10 Cng thc bnh xe 6x4
11 S ch ngi ch 55
1.2.1.2.2 ng c t
(1) (2) (3) (4)
1 Kiu ng c D6BR(diesel)2 Loi ng c 4 k,tng p, 6 xylanh
b tr 1 hng thngng
3 ng knh v hnh trnh piston mm 118x115
4 T s nn ca ng c 17,5
5 Khi lng ng c kg 545
6 Chiu rng ng c mm 585
7 Chiu cao ng c mm 8308 Chiu di ng c mm 1233
9 S xylanh ci 6
10 M men xon cc i ca ngc
Kg.m/vph 52,5/1400
11 Cng sut cc i ca ng c ml/vph 188/2900
12 Tc chy khng v/ph 550 600
13 Th t lm vic ca xylanh 1-5-3-6-2-4
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1.2.1.2.3 H thng truyn ng
(1) (2) (3) (4)
1 Ly hp a n kh vi vng lxo(vn hnh bng thulc)
2 ng knh ngoi ca a mm 380
3 T s truyn- S 1- S 2- S 3
- S 4- S 5- S li
5 tin, 1 li, ng tc.4,6293,21642,582
1,4701,0407,216
4 S cu ch ng 1
5 H s gim sc 5,571:1
H. 1-5. Hp s
1.2.1.2.4 H thng treo
(1) (2) (3) (4)
1 H thng treo trc, sau Loi nhp l
2 Gim chn trc, sau Loi ng hai v, cchiu tc dng
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Ng Quang Tun 44DLOT n tt nghip
1.2.1.2.5 H thng li
(1) (2) (3) (4)
1 Loi Lin hp (du v in)
2 Gc li trong v ngoi 47 1 v 33,9 1
3 Tay li Loi bi khng c tr lc
1.2.1.2.6 H thng nhin liu
(1) (2) (3) (4)
1 Dung tch thng nhin liu Lt 200
2 Dung tch thng nht Lt 13
3 Bm chuyn nhin liu Kiu piston
4 Bnh lc nhin liu Bnh lc giy
5 Bm cao p Kiu bm Bosh A
6 ng knh piston bm cao p mm 9,5
7 Vi phun-s vi phun cho 1 xylanh
-ng knh l phun
Vi
mm
1
0,31
1.2.1.2.7 H thng phn phi kh
(1) (2) (3) (4)
1 S lng van cho mi xylanh-Np-X
VanVan
11
2 Khe h xupap np mm 0,43 Khe h xupap x mm 0,4
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Ng Quang Tun 44DLOT n tt nghip
1.2.1.2.8 H thng bi trn
(1) (2) (3) (4)
1 Bm du bi trn Bm bnh rng
2 Van an ton Kiu van bi
3 Lc du Kiu lc giy
4 Van iu khin Kiu van piston
1.2.1.2.9 H thng lm mt
(1) (2) (3) (4)
1 Phng php lm mt Bng nc ngt vi nhit nnh.
2 Bm lm mt Kiu ly tm
3 Nhit nc vo ngc
0C 50 60
4 Nhit nc ra ng c 0C 72
1.2.1.2.10 H thng khi ng(1) (2) (3) (4)
1 B khi ng in
H. 1-6. My khi ng
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Ng Quang Tun 44DLOT n tt nghip
1.2.1.2.11 H thng phanh
(1) (2) (3) (4)
1 Loi h thng phanh Tr lc thu lc
2 ng knh trng phanh trc xrng
mm 370 x110
3 ng knh trng phanh sau x rng mm 370 x150
4 Phanh tay Kiu dy in
5 ng thng bnh xe trc mm 36,5
6 ng thng bnh xe sau mm 38,1
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Ng Quang Tun 44DLOT n tt nghip
1.2.1.2.12 H thng x
S dng kh x cung cp cho tua bin tng p cung cp khng kh c p
sut cao vo bung t1.2.1.2.13 H thng in
(1) (2) (3) (4)
1 c quy (12V x 150Ah) x 2
2 Cng sut my pht in 24V 110A
3 Cng sut khi ng 24V 6kw
1.2.1.2.14 H thng ng m ca xe
Ca xe c ng m t ng bng kh nn
1.2.1.2.15 H thng lnh
-My lnh NANDO
+S qut thi:8 qut
+S qut nng:4 qut
-My nn mi cht lnh c dn ng t ng c
H. 1-7. V tr lp t my nn mi cht lnh
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1.2.2 c im k thut v cu to ca ng c D6BR s dng trn xe but
Thnh Ph Nha Trang1.2.2.1 Gii thiu chung v v tr ng c trn xe but
ng c D6BR l ng c diesel do hng Huyndai ch to. Tt c xe but
Thnh Ph Nha Trang u dng loi ng c ny.
ng c D6BR l ng c 4 k, 6 xylanh b tr mt hng thng ng, tng
p, phun trc tip
ng c c bi trn bng mt h thng du p lc, nh mt bm bnh
rng cp du. piston c lm mt bng du nhn. Xylanh ng c l xylanh kh
thay th c mt cch r dng khi c h hng. ng c c lm mt bng h
thng lm mt tun hon kn, bm nc lm mt kiu ly tm.
ng c c b tr sau thng xe. S b tr ny khc phc c nhng
nhc im cc loi xe c kiu b tr ng c trc v ngoi bung li. b tr
nh vy m bo cch nhit, cch m tt cho ngi li v hnh khch ngi trn xe.
ng thi vic b tr nh vy gip cho vic bo qun v sa cha tt hn.
Bnh c quy v thng ngh c b tr pha di bn phi thng xe1.2.2.2 c im k thut ca ng c
- Kiu ng c :ng c diesel 4 k, 6 xylanh, 1 hng thng ng, tng p ,
lm mt bng h thng tun hon kn.
- Kiu bung t: bung t thng nht.
-ng knh xylanh: 118 mm.
- Hnh trnh piston: 115 mm.
-Dung tch xylanh: 7,545 cc
-Cng sut cc i: 188/2900 ml/vph
-Mmen xon cc i: 52,5/1400 kg.m/vph
-Tc chy khng nh nht: 500 600 rpm
- Tc chy khng ln nht: 3180 3220 rpm
-Kch thc ng c :
+Chiu di ng c: 1233 mm
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+Chiu cao ng c: 830 mm
+Chiu rng ng c: 585 mm
+Trng lng ng c: 545 kg-T s nn: 17,5
-Phng php khi ng: khi ng in
-Cng sut khi ng: 24V/5kw
-Khe h xupap: 0,4 mm
-H thng nhin liu :
+Bm cao p: kiu Bosh A
+Vi phun: S l 5
ng knh l: 0,31 mm
Gc lch: 1600
+p sut phun: 220 kgf/cm2
+Loi nhin liu: diesel
+Lc nhin liu: li lc bng giy
+Th t n: 1-5-3-6-2-4-1-H thng bi trn:
+Bm du bi trn: bm bnh rng
+B lc du: li lc bng giy
+Nhit du bi trn: 70 900C.
-H thng lm mt
+Phng php lm mt: Lm mt nc ngt vi nhit n nh
+Bm nc lm mt: kiu ly tm
+Lm mt hng lot:22 lt
+B iu chnh nhit: Nhit m van: 80 900C
Nhit nng van: 950C
+B tn nhit: p sut m van 0,4 0,6 kgF/cm2 .
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1.2.2.3 Nhm piston, xylanh, np xylanh
1.2.2.3.1 Nhm piston
Nhm piston gm nhng chi tit : piston, cc vng gng, cht piston v cihm cht. Piston nhn p lc kh t pha nh, truyn ti trc khuu, qua thanh
truyn v ngc li. N b nung nng bi kh chy trong bung t. Nh vy piston
va b ti c va chu ti nhit. p sut cao nht trn nh piston khong (60-120)
KG/cm2 .Nhit trung bnh u piston khong (400-500)0C. Ngoi ra, khi
chuyn ng, cc vng gng v phn dn hng ca piston cn chu mi mn mnh
do ma st vi xylanh nhit cao v bi trn km gy ra.
Cng vi xylanh v np xylanh to thnh bung lm vic kn ca ng c ,
nhng piston li chuyn ng. Nhim v lm kn ca n cn m li kh. Phi tht
kn nhng li cho php chuyn ng d dng ma st t.
Cc vng gng hi v vng gng du l tit my ph trong khp trt piston-
xylanh m bo c nhim v ny.
Vt liu v cu to nhm piston phi lm sao cho n chu c ti c, ti
nhit; t b mi mn v m bo kh lt xung hp cacte t nht, du lt ln bungt t nht.
Piston ng c D6BR c c bng hp kim nhm c s gin n nhit nh
v to nhit tt. nh piston lm, bung t nm trong nh piston. c bit l p
chuyn ng khng kh theo vng xoy trong xylanh.
Piston c 3 vng gng: 2 vng gng kh v 1 vng gng du lp trn u
piston. Vng gng th nht chu la c m crom tng bn.
ng c D6BR c bung t thng nht loi phun trc tip.
u im: kt cu n gin, din tch bung t b nn t tn tht nhit, t hao
nhin liu, khi ng r dng m khng cn bugi xng my.
Nhc im: t s nn cao, p sut du ln
Piston c lm mt bng du bi trn t di ln nn piston t b qu nhit,
gin n nh, t gy ng sut v b kt piston.
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Piston:-Khe h cht piston
+Kch thc tiu chun:0,01 0,02 mm
+Kch thc gii hn:0,05 mm
-Khe h gia cht piston v thanh truyn
+Kch thc tiu chun:0,02 0,05 mm
Cht piston-ng knh ngoi cht piston:
+Kch thc tiu chun:38,01 38,02 mm
+Kch thc gii hn: 38,05 mm
Vng gng pistonVng gng Kch thc tiu
chun (mm)Kch thc gii
hn (mm)
Khe h gia vng gng v rnh vng gng-Vng gng la-Vng gng th 2
-Vng gng du
0,09 0,130,05 0,08
0,03 0,06
0,20,15
0,15Khe h u vng gng 0,35 0,55 1,5
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H. 1-8. Piston
H. 1-9. Hnh dng nh piston
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1.2.2.3.2 Xylanh
ng xylanh cng piston to ra khp trt trong c cu piston-thanh truyn
trc khuu. ng thi n cng np xylanh v nh piston to ra bung lm vic cang c. lm tt 2 nhim v trn ng xylanh phi kn v cho piston trt d
dng
ng c D6BR s dng lt xylanh kh, xylanh c lm mt nhit
khng i bng nc. Xylanh c c bng thp c bit, c kh nng chng mn
v h hng cao. N l chi tit c dy tiu chun, chng gin n cc b v c
tng bn.
Tn thng s Kch thc tiu chun(mm)
Kch thc gii hn (mm)
ng knh trong cxylanh
118,000 118,030 118,25
Phn nh ra ca xylanh 0,03 0,10
H. 1-10. Hnh dng lt xylanh
1.2.2.3.3 Np xylanh
Np xylanh cng xylanh v nh piston to ra bung lm vic ca ng c,
nht l hnh dng v th tch ca bung t. Np xylanh chu p lc kh ln v nhit
cao.
Np xylanh ng c D6BR c c bng loi thp c bit, trn np xylanh
b tr xupap ht, x,vi phun, ca x, ca np, ng nc lm mt
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C th ni: np xylanh l tit my rt phc tp v mt cu to. ng thi ng
sut c, ng sut nhit va cao, va rt chnh lch gia cc vng. Chnh v vy,
thnh vch ca np xylanh phi lm sao c b dy tng i u trnh nt khi tinng, nhit cao.
ng c D6BR mi xylanh c 1 xupap ht, 1x.
ng knh x bcren (mm)
M14x2,0Gi tr lc sitbulng np xylanh
Lc sit (kgf/m) 20 22
H.1-11. Mt di np xylanh ( mt tip xc vi bung t)
H. 1-12. Mt trn np xylanh
H. 1-13. n gnh, trc n gnh, np y
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Ng Quang Tun 44DLOT n tt nghip
H. 1-14.iu chnh khe h nhit
1.2.2.4. H thng nhin liu
1.2.2.4.1.Nhim v, yu cu,cu to:
H thng nhin liu c nhim v lc sch ri phun nhin liu vo bung t
theo cc yu cu sau:
Cung cp vo bung t nhng khi lng du xc nh, ph hp vi ch lmvic nh ca my v c th iu chnh c
Thi im v thi gian cung cp phi chnh xc ( nht l thi im bt u ) v cth iu chnh c
Du a vo phi dng cc ht nh, ng u (kch thc ht c 3 5 ) vphn b u trong khng gian bung t. To iu kin cho du bay hi d dng,
nhanh chng v ho trn u vi khng kh nn, thnh hn hp d t bc chy nht.
S lng du cung cp theo thi gian cung cp - lut cung cp - phi to ra s cpnhit tt nht cho chu ch nh lm vic ca my. Ngha l: khng qu nhiu giai
on trc im cht trn mc tng p trong giai on chy ng tch khng
qu cao, my lm vic khng b cng. cng khng qu nhiu giai on sau,
my khng b gim hiu sut nhiu v khng b qu nng.
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H. 1-15. H thng nhin liu
1- Bnh lc kh ; 2- Hi du vi phun; 3- Vi phun; 4- ng cao p; 5- Bnh
lc th; 6- Bnh lc tinh; 7- Kt nhin liu; 8- Van kho; 9- Nt x du; 10- Bm
thp p; 11- ng hi du; 12- Bm cao p
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Ng Quang Tun 44DLOT n tt nghip
1.2.2.4.2.Vi phun:
Chc nng phun nhin liu cao p vo bung t vi cu trc tia nhin liu
ph hp vi phng php t chc qu trnh chy.c im vi phun ng c D6BR:
-Kiu 5 l.
-p sut phun 220-230kg/cm2 .
-ng knh X s l X gc lch: 0.31 X 5 X 160 (mm X l X )
Nguyn l hot ng: Bm cao p cung cp du c p sut cao vo vi phun.
Khi p lc du n mt gi tr nh mc ln thng c p lc l xo iu
chnh, kim phun s c nng nn tch khi b ca n trn u phun, du s
c phun vo bung t. Nhin liu phun ra di dng sng m, khi p sut du
t 220 kg/cm2 th du nng kim phun khi b v phun vo bung t qua l vi
phun
u im ca vi phun nhiu l:
-p sut phun cao hn vi phun 1 l
-Bn hn, t b chy, b kt kim phun-Khi phun mi l cho ra mt tia vi gc nn nh, cc tia hp vi nhau to
gc nn ln ph hp vi loi bung t thng nht
Nhc im: Vi phun nhiu l d gy tc nghn cc l phun.
H. 1-16. Vi phun
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Ng Quang Tun 44DLOT n tt nghip
H. 1-17. Cc chi tit tho ri ca vi phun nhin liu
R- ng rc co du vo; F- Khu sit u phun vo thn vi phun; B- u
phun; A- Kim phun; I- Thn vi phun; P- Trc y; r- l xo; a- a ta l xo; E-
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Ng Quang Tun 44DLOT n tt nghip
ai c vt iu chnh p sut phun du; C- c kho; T- Vt iu chnh p sut phun
du.
H. 1-18. Cu to ca vi phun
1- u phun; 2- Kim phun; 3- c chp u phun; 4- Cht; 5- Trc y; 6-
c nh v vi phun vo np xylanh; 7- Thn vi phun; 8- L xo; 9- ai c chp l
xo; 10- ai c vt iu chnh p xut phun du; 11- Np y; 12- Bc; 13- Ci lc
khe; 14- u ni ng; 15- Rnh du; 16- m; 17, 19- Mt cn kn st; 18- Khoang
du cao p; 20- L phun
1.2.2.4.3.Bm cao p:
Chc nng:
- Nn nhin liu ti p xut rt cao ( khong 100 1500 bar ) ri y n vi
phun (chc nng nn).
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Ng Quang Tun 44DLOT n tt nghip
- iu chnh lng nhin liu cung cp vo bung t ph hp vi ch
lm vic ca ng c ( chc nng nh lng ).
- nh thi im bt u v kt thc qu tr nh phun nhin liu (chc nngnh thi).
c im k thut bm cao p ng c D6BR:
-Kiu Bosch A
-Th t phun: 1-5-3-6-2-4
-ng knh piston bm: 9.5 (mm)
-Khe h y trc cam iu khin: 0.02-0.06 (mm)
-Khe h gia thanh rng iu khin v bnh rng chuyn:
+Kch thc tiu chun: 0.15 (mm)
+Kch thc gii hn: 0.3 (mm)
-Bm cao p ng c D6BR c 6 piston bm c dn ng bng trc cam.
mi piston bm phc v cho 1 vi phun. V vy s xylanh bm bng s xylanh
ng c.
u im: Gc phun sm c iu chnh ph hp vi mi ch lm vicca ng c. kt cu thn bm gn nh, dng bm piston ngn ko d iu chnh
tu lng nhin liu.
Nhc im:Cu to phc tp, iu chnh v sa cha kh khn.
-Bm cao p ng c D6BR c thn bm, cc cp piston-xylanh, van trit
hi, trc cam, con i v c cu xoay piston.
Piston v xylanh l 2 b phn lm vic c bn ca bm, cp piston-xylanh
c ch to chnh xc bng thp hp kim, nhit luyn n cng cao. vic lp
ghp cp piston-xylanh i hi chnh xc m bo nhin liu khng b r r. Van
trit hi v van cng l mt cp lp ghp i hi chnh xc.
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Nguyn l hot ng
H. 1-19. Cu to chi tit ca bm cao p1- Bi kim; 2- Trc con ln; 3- Con ln; 4- Con i; 5- Bulon; 6- ta di;
7- Piston; 8- c gi np thm; 9- L xo bm; 10- c xoay piston; 11- Np thm;
12- Vt nh v xylanh; 13- Xilanh; 14, 15- v thn van cao p; 16- L xo valve
cao p; 17- L ht v x du; 18- Khoang cha du p sut thp; 19- Thanh rng-
thc nhin liu; 20- Vnh rng; 21- c hm vnh rng; 22- Thn bm; 23- bi;
24- Trc cam bm cao p; 25- rnh nh hng; 26- Vt x kh.
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H. 1-20. Cc chi tit tho ri ca bm cao p
1- L xo van nn; 2- Van nn; 3- V bm; 4- Np; 5- V bi; 6- Gi ; 7-Thanh rng iu khin; 8- Trc cam; 9- V iu khin.
H. 1-21. Nguyn l lm vic ca bm cao p
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H. 1-22. Hnh nh bm cao p thc t
Khi piston ngn ko 7 v tr thp nht, du qua l 0 v 01 np y khoang
nh piston. Lc con i 4 c cam du i, n s y piston i ln, cho n khi
nh piston va y kn cc ca 0 v 01th du c tng p, thng lc l xo 16,
nng valve cao p ln, bt u cung cp du ln ng cao p, a ti vi phun. S
cung cp tip tc cho n khi mp vt iu chnh ca piston h m ca 01, th du
t trn nh piston theo rnh dc, qua ngn ko u piston thot ra ca 0 v 01,
kt thc qu trnh cung cp.
1.2.2.4.4 ng dn nhin liu.
Gm c ng cao p v ng thp p. ng cao p dn nhin liu c p sut cao
t bm cao p n vi phun, vt liu ch to i hi phi chu c p lc cao. ng
thp p dn nhin liu t thng cha n bm cao p v dn nhin liu hi v thng
cha.1.2.2.4.5 Lc nhin liu.
Trong h thng nhin liu ca ng c diesel c cc b phn c ch to v
lp rp vi chnh xc rt cao, nh : u phun, cp piston xylanh ca bm cao p,
van trit hi. Cc b phn ny rt d bi h hi nu trong nhin liu c tp cht c
hc. Trong du c ln c nc, nc ln trong nhin liu s lm cho nhin liu
khng chy c lc phun vo bung t, ng thi lm cho ti bm kt cng trong
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Ng Quang Tun 44DLOT n tt nghip
xylanh bm gy nn gy hng. Bi vy nhin liu phi c lc sch trc khi n
bm cao p.
H. 1-23. V tr cc b lc trong h thng nhin liu
a) Lc s cp.
Bu lc s cp t gia thng nhin liu v bm tip vn. Li ca lc ny
lm bng li ng c l tha khong 0,1 mm, bn ngoi li lc c ci co. Khi taxoay nm, pha di bu lc, co s lm ri cn bn quanh li lc xung y bu
lc. Nt x nc v cn bn b tr di y bu lc.
H. 1-24. Kt cu bu lc s cp
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b) Lc th cp.Li lc th cp l nhng khoanh n dy chng bn ngoi mt ng nhiu l.
Nhin liu t bu lc s cp vo l D, chui qua lp n vo ng trung tm thotxung l E n bm cao p. Bn trong rc co du d tr v c b tr van du trn.
Cng dng ca van ny l bo m mt p sut tip vn ti thiu buc nhin liu
phi chui qua lp b lc cung cp cho bm cao p. Van c cu to gm mt vin
bi trn v l xo. Nu khi sc ra bu lc ta nh ri hay lm hng van ny, nhin
liu s khng cung cp cho bm cao p, ng c gim cng sut thy r. Khi p
sut tng qu khong 0,5 kG/cm2, van m cho nhin liu trn tr li thng cha.
H. 1-25. Kt cu bu lc th cp
1.2.2.4.6 Bm thp p.Bm thp p c nhim v a du t qua bnh lc tinh ti bm cao p.
Nng sut ca bm chuyn phi bng (1,5 2 ) ln lng cung cp nh mc
ca ng c. Ct p c xc nh theo v tr tng i ca bm thp p, bnh lc
v bm cao p v phi ln thng tr lc ng ng v ch yu to ra p
sut thm thu qua lc.
ng c D6BR c trang b bm thp p kiu piston.
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u im: c th iu chnh c p lc du theo yu cu.
Nhc im: Cu to phc tp.
C cu iu chnh: nu dch chuyn thanh rng v pha trc ca b iu tclng cung cp nhin liu tng nn v tin hnh ngc li th lng nhin liu
gim.
1.2.2.4.7 B iu tc.
B iu tc dng trn ng c D6BR l b iu tc mi ch . nhim v b
iu tc l gi cho tc quay ca ng c mt gi tr khng i cho d ti ca
ng c c thay i bt k tc l thay i lng cung cp nhin liu cho ph hp
vi mi ch hot ng ca ng c.
H. 1-26. B iu tc1- Bn p; 2- Thanh rng nhin liu; 3- Tay n;
4- Qu vng; 5- Khp trt; 6- l xo
Nguyn l hot ng: y bn p 1 s thay i bin dng ban u ca l xo
6. Mi v tr bn p 1 s tng ng vi mt tc iu khin lc ly tm ca qu
vng 4 thng lc l xo lm qu vng 4 chuyn dch xa tm quay v y khp trt 5
sang tri ng thi ko thanh rng 2 v pha gim gct, thc hin nhim v iu chnh
tc ng c .
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1.2.2.5 H thng np - x
H thng np- x (cn gi l h thng thay i kh hoc h thng trao i kh) cchc nng lc sch khng kh ri np vo khng gian cng tc ca xylanh v x kh
thi ra khi ng c, cc b phn c bn ca h thng np-x bao gm: lc khng
kh, ng np, ng x, bnh gim thanh v c cu phn phi kh
Gi tr lc sitTn thng s ng knh x bc ren(mm) Lc sit(kgf/m)
Bulng ng gp np
ai c ng gp xM8x1,25M10x1,25
1,9 2,84,2 4,6
1.2.2.5.1 Cu to ng gp np
H. 1-27. Cu to ng gp np
1- Np, 2-m lt
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1.2.5.1.2 Cu to ng gp x
H. 1-28. Cu to ng gp x
1- ng gp x; 2- m; 3- Np
1.2.5.1.3Lc khng kh:
chc nng lc sch khng kh trc khi vo bung t. lc khng kh ca
ng c D6BR c cu to nh hnhv
H. 1-29. Lc khng kh
1- Thn; 2- Phn t lc; 3- Np
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Ng Quang Tun 44DLOT n tt nghip
1.2.2.5.4 C cu phn phi kh
C cu phn phi kh c chc nng iu khin qu tr nh np kh mi vo
khng gian cng tc ca xylanh v x kh thi ra khi ng c.Yu cu vic np phi y. Ngha l h s np phi cao. Vic x phi sch.
Ngha l h s kh st phi thp.
H. 1-30. C cu phn phi kh
1- Trc cam; 2- Con i; 3- m; 4- ng dn hng; 5- ng chn trn; 6-
a y; 7- Vt iu chnh; 8- n gnh; 9- Trc n gnh;10- trc n gnh;
11- Mng hm; 12- Cone hm; 13- Vnh khuyn hm; 14- L xo xupap; 15-
Xupap; 16- Bc n gnh; 17- a ta l xo xupap; 18- Bc dn hng;
a)Xupap
Xupap l mt loi van c trng ng c t trong, c chc nng ng, m
ng ng np v x. Mi xylanh ca ng c D6BR c 1xupap np chc nng
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Ng Quang Tun 44DLOT n tt nghip
ng m ng ng np, 1xupap x chc nng ng m ng ng x. xupap b tr
theo kiu treo trong np xylanh. Trong qu trnh ng c hot ng, xupap x chu
tc dng thng xuyn ca kh thi c nhit cao, nhit ca nm xupap x cth ti 600-7000C, cho nn n c ch to t thp hp kim cht lng cao. Xupap
np thng xuyn c lm mt bng dng kh mi nn nhit ca n khong
400-5000C . tng cng lu lng kh np vo bung t, nm supap np ln
hn nm xupap x.
b) n gnh
n gnh di chuyn ln v xung bng lc nng ca cam qua con i v a
y lm m hoc ng xupap np, x. u n gnh pha a y c b tr 1vt
iu chnh khe h nhit.
c) a y
a y c ch to bng thp ng, thnh mng. hai u c dng chm
cu. a y chuyn ng qua li dc trong ng dn hng n n gnh.
d) Con i
Con i truyn chuyn ng tnh tin cho a y. Con i chuyn ngquay quanh ng tm ca n s lm cho mt tip xc ca con i vi cam mn
u.
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Ng Quang Tun 44DLOT n tt nghip
Tn thng s Kch thc tiu
chun(mm)
Kch thc gii
hn(mm) cong ca a y 0,4
ng knh ngoi con i 31,06 31,10
ng knh trc n gnh 24,01 24,08
ng knh ngoi thn van 8,96 8,97 8,85
ng knh trong ng dn hng van-Np
-X
9,04 9,06
9,07 9,10Ti trng ca l xo(N)-L xo trong-L xo ngoi
93240
20579
di t do ca l xo-L xo trong-L xo ngoi
55,158,1
52,155,1
Gi tr lc sit bulng n gnh ng knh x bc
ren(mm)M8x1,25M10x1,5
Lc sit(kgf/m)
1,03,5
e) Trc cam
Trc cam lm bng thp thng, c trc v mt cam c ti b mt v mi
bng. Bin dng cam l mt ng cong lin tc c c tnh gim chn, s lm
gim va p theo chu k trn xupap v lm tng bn cho trc cam.
Tn thng sKch thc tiu chun
(mm)Kch thc gii hn
(mm)
Chiu cao vu cam- Cam van np- Cam van x
49,54749,307
49,04748,807
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CHNG 2. KH NNG S DNG NHIN LIU THAY
TH CHO I XE BUT THNH PH NHA TRANG
2.1. Phng n lp t h thng s dng nhin liu thay th cho ng cdiesel
D6BR trn xe but thnh ph Nha Trang.
2.1.1. H thng s dng nhin liu thay th n
H thng s dng nhin liu thay th n l h thng ch s dng duy nht
mt loi nhin liu thay th.
u nhc im ca h thng s dng nhin liu thay th n
* u im:- Do ch s dng mt loi nhin liu thay th ( Biodiesel, LPG ) nn vic ci
hon h thng nhin liu diesel ban u ca xe s dng nhin liu thay th khng
qu phc tp.
- Vic vn hnh, bo dng sa cha n gin hn khi s dng lng nhin
liu.
- Gi thnh ci hon cng thp hn do t phi thay th kt cu ban u
Nhc im
Kh khn khu tip nhin liu thay th, hin nay trn cc tuyn ng
cha c hoc c nhng rt t trm nhin liu thay th (biodiesel, LPG ), v vy lm
gim tnh c ng ca xe
2.1.2 H thng s dng nhin liu thay th v diesel song song.
H thng s dng nhin liu thay th v diesel song song l h thng c th
chuyn i mt cch d dng t dng nhin liu thay th sang nhin liu diesel vngc li trn cng mt ng c trong qu trnh hot ng
u, nhc im
u im:
- Xe c th chy nhin liu thay th hoc chy nhin liu diesel, v vy gii
quyt tt tnh trng tip nhin liu.
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- C th la chn loi nhin liu s dng ph hp vi thc t s dng v vy
va m bo tit kim ti a chi ph cho nhin liu ng thi vn m bo tnh nng
tt nht cho xe. Xe c th chy mi ni m ngi li khng s thiu nhin liu
hoc gi nhin liu cao. Nu xe chy trong thnh ph ta s dng nhin liu thay th
( Biodiesel, LPG ) m bo vn nhim, cn nu xe chy ngoi thnh ph c
th chuyn sang s dng nhin liu diesel m bo cc tnh nng tt nht ca xe.
* Nhc im
- Cu to xe ch nn phc tp, gi thnh chuyn i cao
- S dng 2 loi nhin liu nn ta phi tnh ton, iu chnh sao cho ng clm vic tng i n nh c hai loi nhin liu, khng khc bit ln
- Nu van ng ngt khng tt gy hin tng c hai loi nhin liu cng vo
ng c.
2.1.3 La chn gii php.
Hin ti Thnh Ph Nha Trang khng c trm tip nhin liu thay th
(Biodisel, LPG) no. vic chuyn i ng c xe but ca Thnh Ph sang s
dng nhin liu thay th c th tr thnh hin thc vi chi ph nh nht ( xy dng
s trm tip nhin liu thay th t nht ) m khng nh hng n nhim v vn
chuyn hnh khch trong Thnh Ph v vng ven, Ti chn phng n ci to ng
c xe c th s dng nhin liu thay th v diesel song song.
2.2 Gii php k thut ng c c th s dng nhin liu Biodiesel.
So vi du diesel nht ca biodiesel cao hn , tng hiu qu kinh t v
hiu sut ng cta nn sy nng nhin liu. Vn sy nng nhin liu nhm mc
ch c bn l lm gim nht ca Biodiesel v gn vi nht ca diesel nht,
v vy mt s hn hp ca Biodiesel vi diesel c nht gn bng nht ca
diesel nguyn cht nh B5, B10, B20,ta khng nht thit phi sy nng m c th
dng trc tip nh nhin liu diesel thng thng.
Di y tr nh by s nguyn l h thng nhin liu s dng nhin liu
biodiesel cho ng c D6BR
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H. 2-1. S h thng nhin liu dng nhin liu Biodiesel
1 Vi phun 5 Bnh sy
2 Bm cao p 6 Kt nhin liu Biodiesel
3 Bnh lc 7 Van chn
4 Van ba ng 8 Kt nhin liu Diesel
Nhin liu biodiesel t kt 6 qua van chn ti b nh sy 5, ti y nhin liu
biodiesel c sy nng n nhit quy nh, lm nht ca nhin liu gim
sung theo yu cu s dng. Van ba ng 4 c nhim v ch cho mt loi nhin liuduy nht qua n (diesel hoc biodiesel) theo yu cu s dng. Nhin liu t van 4
qua bnh lc 3 lm sch, sau c bm cao p 2 chuyn n vi phun 1
vo bung t.
C nhiu cch sy nng nhin liu trc khi n vi phun. Di y trnh
by ba phng php thng dng sy nng nhin liu trc khi n vi phun
trn t.
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2.2.1 Bnh sy s dng nc lm mt lm nng nhin liu
Nc lm mt sau khi i lm mt ng c c nhit cao c a ti bnh chanc nng 2, ti y n cp nhit v lm nng nhin liu biodiesel trong ng xon
rut g 1. Nhin liu biodiesel sau khi c nc lm mt sy nng c a ti
bm cao p.
H. 2-2. S nguyn l bnh sy s dng nc lm mt sy nng nhin liu
1 - ng xon rut g; 2 Bnh cha nc lm mt; 3 - Nhit k
S h thng nhin liu dng du biodiesel, c s dng b nh sy nng
nhin liu bng nc lm mt.
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H. 2-3. S h thng nhin liu dng du Biodiesel, c s dng bnh sy nng
nhin liu bng nc lm mt
1 Kt nhin liu Diesel 7 Van x nc sau khi sy nhin liu2 - ng cp nc b sung 8 Bnh sy nhin liu
3 Kt nc lm mt 9 Bnh lc th
4 - Nhit k 10 Van ba ng
5 Kt nhin liu Biodiesel 11 Bnh lc tinh
6 Van chn 12 Nhin liu ti bm cao p
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2.2.2 Bnh sy s dng ngun in mt chiu
Tn dng ngun in mt chiu ca ng c trong h thng khi ng to
ra ngun nhit cung cp cho b sy.u im: sy c lng nhin liu ln, iu chnh nhit nhin liu cn
sy mt cch d dng, c th sy nng nhin liu trong khong gii hn nhit
rng.
Nhc im: tiu hao in s dng cho vic sy nhin liu
S nguyn l s dng ngun in mt chiu cho bnh sy
H. 2-4. S nguyn l s dng ngun in mt chiu cho bnh sy
1 Nhin liu cn sy i vo 6 c qui2 Van chn 7 - Cm bin nhit 3 Van phao 8 Bnh cha nhin liu sy4 Que sy 9 Van chn5 - Thit b iu khin 10 Nhin liu ti bm cao pNguyn l hot ng: Nhin liu cn sy nng c a vo bnh cha nhin
liu 8, ti y nhin liu c sy nng nh que sy 4, que sy 4 c cp in t
c qui 6 bin in nng thnh nhit nng. Vic cp in nh vo thit b iu khin
5, cm bin nhit 7 c nhim v cung cp thng tin v nhit cho thit b iu
khin 5 lm vic, nhin liu sau khi c sy nng uc a ra ngoi qua van chn
9 theo ng 10 ti bm cao p
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2.2.3 Bnh sy tn dng ngun nhit kh x
u im: Tn dng c ngun nhit kh x c sn ca ng c, thit b ch
to n gin, thi gian sy nng nhin liu ngn.Nhc im: tin cy khng cao, kh iu chnh, nhit kh x ph thuc
vo ti ca ng c nn khng n nh.
S nguyn l bnh sy dng ngun nhit kh x.
H. 2-5.
H. 2-5. S nguyn l bnh sy dng ngun nhit kh x
1 Kh x t ng c 7 - Nhit k
2 Kh x ra 8 Khoang kh x
3 Van iu chnh lu lng kh x 9 Bnh sy
4 - Ca gi 10 Kh x ra
5 - ng ni mm 11 Nhin liu vo
6 - Qut gi 12 Nhin liu ra
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Nguyn l hot ng: Kh x t ng c 1 c trch mt phn qua van 3 i
lm nhim v sy nng nhin liu, nh ca gi 4 dng kh x i hng ti ng 5
v i vo khoang kh x vo 8 di sc ht ca qut gi 6, ti bnh sy 9 xy ra qutrnh trao i nhit ca dng kh x nng chy ngoi ng v du biodiesel chy
trong ng, kh nng sau khi cp nhit cho nhin liu c a ra ngoi theo ng
10 ti bm cao p.
2.2.4 La chn
Qua trnh by trn ta thy rt r u nhc im ca tng phng php sy
nng nhin liu. cho kt cu ca xe khng qu cng knh, thao tc n gin,
tin cy cao, mang tnh thm m, hin i, ph hp vi chc nng vn chuyn hnh
khch trong ni v vng ven thnh ph. Ta nn chn phng php sy nng
nhin liu bng bnh sy s dng ngun in 1 chiu.
2.2.5 S tng th h thng nhin liu s dng Biodiesel v Diesel song song
(H. 2-6 )
Trong tt c cc b phn chuyn i lp ln xe, Kt nhin liu l b phn chim
nhiu khng gian nht. to m quan v khng lm thay i nhiu kt cu ca xe,ti chn gii php tho kt nhin liu diesel ban u v thay vo v tr hai kt
nhin liu diesel v Biodiesel mi vi t l th tch thch hp.
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2.3 Gii php k thut ng c c th s dng nhin liu LPG.
2.3.1 Gii php k thut ng c c th s dng LPG v diesel song song.
ng c c th s dng LPG v diesel song song ta phi ci tin sao choch vi thao tc chuyn i n gin, ng c c th chuyn t chy nhin liu
diesel sang chy LPG vi diesel lm chc nng phun mi v ngc li. Ni mt
cch c th ta phi a ra gii php k thut h thng nhin liu diesel c th
chuyn t chc nng phun diesel thng thng sang chc nng phun mi v ngc
li ch bng thao tc nhn nt hay gt cn chuyn i. ng thi a ra gii php k
thut lp t h thng cung cp LPG trn ng c. Di y trnh by c th nhng
ni dung nu trn.
2.3.1.1 Gii php k thut h thng nhin liu diesel c kh nng phun mi
2.3.1.1.1 C s l thuyt.
tn dng ti a cc b phn ca h thng nhin liu diesel ang s dng
trn xe but, ng thi hn ch ti thiu vic phi lp t thm nhiu c cu, b
phn khc lm thay i qu ln kt cu v tng chi ph cho vic ci to. Ta s dng
nh la bng cch phun nhin liu minh la bng cch phun nhin liu mi l nh la c thc hin bng s
t chy ca mt lng nh nhin liu diesel phun trc khi piston n im cht
trn.
Nguyn tc ny ging nh ng c diesel, ch c khc l vic iu chnh
cng sut c thc hin bng cch iu chnh th tch kh ga np vo xylanh cn
lng nhin liu diesel phun mi vn gi c nh. Ngi ta gi loi ng c ny l
diesel-gas hay lng nhin liu.
Cc ht nhin liu diesel phun vo bung chy s t bc chy v to ra
chng y im nh la trong hn hp nhin liu-khng kh.
So vi h thng nh la c in dng tia la in, ngi ta thy h thng
nh la kiu ny hiu qu hn nhiu v nng lng do n to ra cao gp nghn ln
so vi h thng nh la tia la in truyn thng v n hu nh khng ph thuc
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vo s phn b hn hp trong bung chy. Trong trng hp , s ra tng p sut
din ra nhanh chng hn v hiu sut ng c c ci thin ng k.
ch lm vic n nh, s gia tng p sut ca loi ng c ny tng tng c Diesel.
Lng nhin liu phun mi rt nh, nh hn c lng nhin liu cn thit
duy tr ch khng ti ca ng c Diesel.
u im ca nh la bng cch phun nhin liu mi
- tin cy khi nh la cao, hiu qu nh la ko di v c th nh la
vi bt k m c no ca hn hp vi iu kin l mc ri ca hn hp ga-
khng kh ln.
- D dng chuyn i sang li ng c Diesel khi c s c h thng gas.
- Hiu sut nhit ng hc cao.
Nhc im ca nh la bng cch phun nhin liu mi.
T s nn cao lm hn ch cng sut cc i theo tnh cht nhin liu kh.
Mc d kh nng chng kch n ca LPG cao nhng nu t s nn cao hn mc cho
php s gy hin tng kch n lm cng sut ng c gim, sut tiu hao nhin
liu tng v gy h hng ng c . Trong khi , vic nh la bng tia la in
cho php la chn t s nn ti u cho tng loi ga s dng. Tuy nhin vic gim t
s nn s dn n vic gim hiu sut nhit ca ng c.
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2.3.1.1.2 Gii php lp t thit b iu khin lu lng du diesel trn ng
cao p.
Cu to v nguyn l hot ng ca thit b iu khin lu lng du diesel.
H. 2-7. Cu to thit b iu khin lu lng du diesel
1 - Cun dy 5 - Du n vi phun2 Li thp 6 - Du hi3 Ty van 7 Van mt chiu4 - Du t bm cao p nThit b iu khin lu lng du gm ba b phn chnh:
-ng hnh tr, hai u c ren ni vi ng cao p t bm cao p ti v ngcao p dn ti vi phun.
-Van in t c nhim v ng m van lm thay i lu lng qua ng.
-ng hi du c nhim v hi du d v bm vn chuyn.
Nguyn l hot ng: khi khng cp in, van in t ng, ty van 3 lm chotit din ng ti v tr nh li, lu lng du diesel theo ng 5 ti vi phun ti, thc hin chc nng phun nhin liu mi, do cht lng khng chu nn nn psut du pha 4 tng nn, khi p sut vt qu gii hn cho php, van mt chiu 7 sm ra, hi du theo ng 6 v bm vn chuyn. Khi cp in, cun dy 1 to ra ttrng ht li thp 2 i ln ng thi ko ty van 3 nn, lu lng du qua ng nvi phun tr li b nh thng thc hin chc nng ca h thng cung cp nhinliu diesel thng thng.
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Cu to v nguyn l hot ng ca h thng nhin liu c lp t thit b iu
khin lu lng du trn ng cao p.
H. 2-8. Cu to ca h thng nhin liu c lp t thit b iu khin lu
lng du trn ng cao p.
1- Bnh lc kh ; 2- Hi du vi phun; 3- Vi phun; 4- ng cao p; 5- Bnhlc th; 6- Bnh lc tinh; 7- kt nhin liu; 8- Van kho; 9- nt x du; 10- bm thpp; 11- ng hi du; 12- Bm cao p; 13- Thit b thay i lu lng du; 14- ngdn ga.
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Nguyn l hot ng: Bm 10 ht nhin liu diesel t b nh cha 7 qua lc
th 5 vo bm ri c bm qua bnh lc tinh 6, ti bm cao p 12. Cc bnh lc 5
v 6, lc sch cn bn ln trong nhin liu. Bm cao p y nhin liu i tip nthit b iu khin lu lng 13. Ti y nu van in t ng th ch mt phn nh
nhin liu i tip vo ng cao p 4, ti vi phun phun vo bung chy ng
c, nhin liu d tha thit b iu khin lu lng qua ng hi du 11 tr v
ca ht ca bm chuyn nhin liu 10. Nu van in t m th ton b du t bm
cao p vo ng cao p 4 ti vi phun phun vo bung t, ng hi du 11
ch nhn c du d tha t bm cao p. Mt phn nhin liu r r trong vi phun
i theo ng 2 tr v thng cha.
Khng kh t ngoi tri qua bnh lc kh 1 vo ng np. Ti y nu ng c
ang chy ch ch dng diesel th khng kh s qua xupap np vo bung t,
nu ng c chy bng LPG th khng kh s c ho trn cng vi LPG t ng
14, sau hn hp kh-gas mi qua xupap np vo bung t.
Nhc im c bn ca gii php ny l vic lp t thit b iu khin
lu lng trn ng cao p i hi phi kn st, cc b phn ca thit b phi chuc p sut cao. Mi ng cao p dn n vi phun i hi phi lp t mt thit
b iu khin lu lng v vy dn n chi ph tn km, iu khin v sa cha thit
b kh khn, phc tp.
2.3.1.1.3 Gii php lp t thit b iu khin lu lng du diesel trn ng
thp p.
Cu to v nguyn l hot ng ca thit b iu khin lu lng du
diesel trn ng thp p.
Cu to v nguyn l hot ng ca thit b iu khin lu lng du diesel
trn ng thp p cng ging nh thit b iu khin lu lng du diesel trn
ng cao p. Chng ch khc nhau v vt liu ch to v kn st ca cc chi tit
cu thnh.
Cu to v nguyn l hot ng ca h thng nhin liu c lp t thit b
iu khin lu lng du trn ng thp p.
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H. 2-9. Cu to ca h thng nhin liu c lp t thit b iu khin lu
lng du trn ng thp p.
1- Bnh lc kh ; 2- Hi du vi phun; 3- Vi phun; 4- ng cao p; 5- Bnhlc th; 6- Bnh lc tinh; 7- Kt nhin liu; 8- Van kho; 9- Nt x du; 10- Bmthp p; 11- ng hi du; 12- Bm cao p; 13- Thit b thay i lu lng du; 14-ng dn ga.
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Nguyn l hot ng: Bm 10 ht nhin liu diesel t b nh cha 7 qua lc
th 5 vo bm ri c bm qua bnh lc tinh 6, cc bnh lc 5 v 6, lc sch cn
bn ln trong nhin liu. Nhin liu t b nh lc tinh i tip n thit b iu khinlu lng 13. Ti y nu van in t ng th ch mt phn nh nhin liu i tip
n bm cao p 12, lng nhin liu ny c bm cao p y qua ng cao p 4
ti vi phun vo bung chy ng c, nhin liu d tha thit b iu khin lu
lng qua ng hi du 11 tr v ca ht ca bm chuyn nhin liu 10. Nu van
in t m th bm cao p s y lng du nh mong mun t bnh lc tinh 6 vo
ng cao p 4 ti vi phun phun vo bung t, ng hi du 11 ch nhn
c du d tha t bm cao p. Mt phn nhin liu r r trong vi phun i theo
ng 2 tr v thng cha.
u im ca gii php ny l ta ch cn lp t duy nht mt thit b iu
khin lu lng du trn ng thp p c th lm thay i lng du phun vo
bung t ca tt c 6 vi phun trn ng c .
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2.3.1.1.4 Gii php lp t thit b iu khin thanh rng nhin liu.
iu chnh thanh rng nhin liu ng ngha vi vic iu chnh hnh trnh
c ch ca piston bm cao p, t dn n vic nhin liu vo ng cao p, ti viphun nhiu hay t.
H. 2-10. S nguyn l b iu tc s dng thit b iu khin thanh rng
nhin liu
1 Bn p ga: 2 Thanh rng nhin liu; 3 Tay n; 4 Qu vng ; 5 -Khp trt; 6 L xo; 7 - Khp ni; 8 - Khp ni; 9 - Khp ni; 10 - Cn iu
khin
Nguyn l hot ng: khi ng c chy nhin liu LPG, lng du diesel
phun vo ch cn mt lng nh. Ta tc ng vo c cu iu khin 10 ko tay n
7 n khp vi khp 9 ng thi ct hn b iu tc ca ng c, thanh rng nhin
liu 2 dch chuyn qua tri lm cho hnh trnh c ch ca piston bm cao p ngn
li, du diesel ti vi phun t hn. Khi ng c chy diesel, nh c cu iu khin10, tay n 7 n khp vi khp 8, ko thanh rng nhin liu tr v v tr bnh
thng, b iu tc nhiu ch ca ng c hot ng b nh thng theo chc
nng ca n.
Nhc im ca phng php: vi khng gian c hn ca ng c vic lp
t thm mt c cu iu iu chnh thanh rng nhin liu tr nn kh khn.
chnh xc, tin cy km, c th lm hng b iu tc nu c cu iu khin khng
ngt b iu tc dt khot. Cc chi tit trong c cu i hi phi nh gn , chnh
xc.
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2.3.1.1.5 Gii php s dng h thng nhin liu kiu tch phun.
H. 2-11. S h thng nhin liu kiu tch phun
1-Bm ngn ko 6- Cn y2-Trc lch tm 7- Trc iu chnh3-Bnh tch t 8- Cam4-L xo xupap 9- Hp xupap5-Xupap phn phi 10- Vi phun
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Nhin liu c nn trong bm cao p ri c cung cp cho cc b nh tch
phun. Thi im bt u cung cp nhin liu vi phun c xc nh vo lc
trit tiu khe h gia u mt trn ca cn y v ui xupap. Lng cung cpnhin liu chu trnh c iu chnh bng trc iu chnh 7, khi mun h thng
nhin liu lm nhim v phun mi hay lm nhim v phun diesel bnh thng, ch
cn tc dng vo trc ny. Trn trc c c cu lch tm dng iu chnh lng
cung cp nhin liu chung cho tt c cc xylanh. Khi ta quay trc 7 i mt gc xc
nh no th khe h gia con i v ui xupap s thay i, do vy thi gian
nhin liu t bnh tch t cung cp cho vi phun cung thay i theo. Thi im bt
u cung cp nhin liu c thay i cng vi thi im kt thc cung cp (vi tr
s thay i nh nhau) nh mt cam i xng c nng ln nht trng vi v tr
piston im cht trn.
kim tra p sut nhin liu trong h thng, ngi ta lp vo hp xupap
mt ng h o p sut. Trong hp c nhiu loi xupap khc nhau: xupap x, xupap
bo him, xupap ng, m h thng.
u im: c th iu chnh lng nhin liu diesel phun mi vo bung tnhiu hay t nh mong mun.
Nhc im:
- Mi vi phun cn lp t mt xupap phn phi
- Phi lp t thm mt trc cam m xupap phn phi v mt h thng truyn
ng n cam, nhm xc nh thi im m xupap ny.
Kt lun: gii php ny ch nn p dng ch to ng c hon ton mi,
c cng sut ln. nu p dng ci tin trn xe but t mang tnh kh thi do phi
lp t thm nhiu c cu lm cho ng c tr nn cng knh, phc tp, chi ph
chuyn i cao
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2.3.1.1.6 Gii php lp t h thng phun nhin liu mi song song vi h
thng phun nhin liu diesel c sn.
H. 2-12. S h thng phun nhin liu mi song song vi h thng nhin
liu diesel
Cu to v nguyn l hot ng: h thng cung cp du diesel trn ng c
c chia lm hai h thng ring r, mt cho hot ng ca ng cch s dng
diesel v mt cho hot ng ca ng c s dng LPG v diesel lm nhin liu
phun mi.
Nhin liu diesel phun mi u tin c cung cp n b phn bm, bao
gm b nh lc, iu ho p sut v mt bm phun nhin liu mi loi piston dnng bng in. Bm phun nhin liu mi lm p sut nhin liu mi tng nn xp
x 1000 bar. Nhin liu sau khi phn b qua h thng ng cung cp chung c p sut
cao n vi phun trn np xylanh. Thi im v khong thi gian phun nhin liu
mi c iu khin bng in.
H thng cung cp nhin liu diesel thng thng, bm cao p c dn
ng bng cam. T bm cao p, nhin liu c p sut cao i n l xo ti ca vi
phun, tt c c thit k theo tiu chun ca ng c diesel.
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u nhc im ca gii php:
H thng lm vic vi tin cy cao, mang tnh hin i. Gii php ny ch
nn p dng ch to ng c hon ton mi, nu p dng ci tin trn xe butt mang tnh kh thi do phi thay i v lp t thm nhiu b phn v h thng in
iu khin bm phun nhin liu mi t tin v vy gi thnh chuyn i s cao.
2.3.1.1.7 La chn gii php phun mi
Qua phn tch 5 gii php k thut ci hon h thng nhin liu diesel h
thng c kh nng thc hin chc nng phun mi nhin liu c c trnh by
trn, ti la chn gii php k thut lp t thit b iu khin lu lng du trn
ng thp p gia bm cao p v bnh lc tinh, lp t trn ng c D6BR s
dng trn xe but thnh ph Nha Trang. Gii php ny ph hp vi cu to ca loi
ng c D6BR, mang tnh hin i v tin cy cao, ng thi chi ph lp t so
vi cc gii php khc thp, t phi thay i kt cu ban u ca h thng nhin liu
v vy khch hng s cm thy hi lng hn.
2.3.1.2 Gii php k thut lp t h thng cung cp LPG trn ng c
Cho n nay, h thng phun nhin liu kh vo ng np nh chnkhng ti c gp np c dng ph bin nht. Tuy nhin, nhng h thng phun
nhin liu mi ang c nghin cu p dng th hin nhiu u im hn, c bit
l h thng phun nhin liu dng kh ho lng ngay trc soupape np. H thng
ny c u im l ngn chn s bc chy ca hn hp trn ng np, hiu sut ca
ng c c nng cao v mc pht nhim gim i r rt.
LPG c th cung cp cho ng c dng kh hay dng lng. u im ca
vic s dng LPG di dng kh l s ng nht hon ton ca hn hp gas-khng
kh v trnh hin tng t thnh ng np bi nhin liu lng, hin tng ny rt
nhy cm khi ng c khi ng v khi ng c lm vic ch chuyn tip.
iu ny cho php gim c mc pht sinh nhim. Nhc im ca vic
cung cp dng ny l qu trnh iu khin di v s cung cp gas lin tc lm hn
ch kh nng khng ch t l khng kh / gas. c bit l giai on qu ca ng
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c. Cng cn nhn mnh thm rng cng sut ng c gim i khong 8% do tn
tht lng khng kh np do kh gas chim ch.
H thng cung cp LPG bng cch phun dng lng cho php s dng uth ca LPG hn ch nhng nhc im trn y. u im ca vic phun LPG
lng l to kh nng kim sot c m c mi ln phun vi thi gian rt
ngn v vy c th p dng cc bin php hu hiu nhm gii hn mc pht
nhim khi ng c lm vic ch qu . S bc hi LPG lm gim ng k
nhit kh np do lm tng h s np ca ng c. Mt khc, mng nhin liu
lng bm trn ng np khng ng k g so vi khi ng c lm vic vi xng.
iu ny thun li cho vic lm gim mc pht sinh HC.
Tuy nhin, vic s dng vi phun thay v hng khuych tn do lm gim thi
gian to hn hp v mt nhin liu cung cp dn n s khng ng nht ca
hn hp v do c nguy c lm tng nng CO trong kh x.
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2.3.1.2.1 Cu to v nguyn l hot ng ca h thng cung cp LPG vi
phng php to hn hp LPG-khng kh kiu khuych tn.
a) Gii php k thut lp t hng khuych tn (hng venturi) gia c gp npv bnh lc khng kh.
Khi ng c ang t ch chy nhin liu diesel chuyn sang chy LPG
vi diesel lm chc nng phun mi th chn ga iu chnh lng nhin liu diesel
vo ng c cho ph hp vi ti ng c diesel khng cn tc dng. V vy ta cn
lp t thm mt s c cu khc ni vi chn ga iu chnh lng nhin liu
LPG vo ng c cho ph hp vi ti. thc hin c nhim v ny ta cn lp
t t mt hng khuych tn, trn c b tr bm ga, bm gi, mt l chy
khng ti di bm ga. Hng khuych tn ny c lp t gia c gp np ca
ng c v bnh lc khng kh.
thc hin vic lp t ny ta c th s dng mt trong hai phng n.
Th nht, s dng nguyn mt b ch ho kh c ca ng c no c cng sut
tng ng. Phng n th hai l ch to mt hng khuych tn hon ton mi.
ch ng trong cng vic, khi mt cng t m kim ch ho kh c ph hp vicng xut ng c, trnh cng knh, to m quan ch lp t thm hng khuych
tn. Ti chn gii php ch to mt hng khuych tn hon ton mi.
H. 2-13. Cu to hng khuych tn
1- Bm ga; 2- L chy khng ti
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b) S h thng cung cp LPG.
H. 2-14. S h thng cung cp LPG
1- Bnh cha LPG; 2- Van an ton; 3- Van chn; 4- Bnh lc; 5 - B gim
p-ho hi; 6 - ng mm; 7- Van an ton; 8- Van in t; 9 - ng khng kh
vo; 10 - B trn; 11 - ng gp np; 12 - Bung t; 13 Cm np - xut; 14- ng
dn nc sau khi lm mt ng c i vo; 15- ng dn nc i ra n Radiator
Kh ho lng LPG trng thi lng trong bnh cha c p xut t 6 8 bar,
di p sut ny khi m van chn 3, LPG lng c dn i theo ng ng cao p,
qua lc 4, n b gim - ho hi, ti y LPG lng c chuyn thnh hi vi p
sut gn bng p sut kh quyn. Sau theo k ht ng c, hi LPG c ht vo
b trn hn hp LPG - khng kh v i vo bung t. b gim p ho hi, qu
trnh gim p ho hi din ra rt nhanh v thu nhit rt nhiu gy ra hin tng
ng bng trn thnh khoang. ng dn nc vo 14 v ng dn nc ra 15 m bo
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cung cp mt lng nc sau khi i lm mt ng c ln tun hon trong
khoang b nhit ca b gim p ho hi chng li hin tng ng bng trn
thnh khoang.Cc van an ton 2 v 7 t ngt v ng mch LPG khi c s c. Van in t
8 dng ng hoc m mch LPG khi s dng.
c) V tr lp t b trn nhin liu LPG - khng kh.
Chc nng chnh ca b trn l to ra t l nhin liu LPG v khng kh
thch hp a vo bung t ca ng c. Lu lng kh np l mt trong nhng
thng s rt quan trng khi lp t b trn.
B trn nhin liu LPG lp trc bm ga
Cch b tr ny, hn hp c c trng bi s iu phi nhin liu LPG b
tc ng bi cc vt cn nh phn t lc gi, hnh dng hnh hc ca hng khuych
tn. Tuy nhin, c th thc hin vic dn nhin liu LPG qua mt l ngang ngay
trong hng khuych tn. Nh vy, hn hp nhin liu LPG - khng kh c tnh ng
nht cao. iu khin mt cch n gin lng hn hp vo bung t nh m
ca bm ga.
H. 2-15. S lp b trn LPG trc bm ga
1- Bnh lc khng kh ; 2- Hng khuych tn; 3- B trn; 4- Bm ga; 5- L
chy khng ti; 6- Bch ni vi c gp np
B trn nhin liu LPG lp sau bm ga.
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Thng tin v lu lng kh b trn c x l bi b bc hi l hm ca
ba thng s: p sut tnh tng i trong b nh lc khng kh, p sut tng i
trong hng khuych tn v sc ht ti trng ca ng c.
H. 2-16. S lp b trn LPG sau bm ga
1- Bnh lc khng kh; 2- Hng khuych tn; 3- Bm ga;
4- B trn; 5- L chy khng ti; 6- Bch ni vi c gp np.
La chn: Da vo nhng u nhc im ca hai cch lp t b trn
trn ti la chn gii php lp t b trn nhin liu LPG trc bm ga.
d) Cu to cc b phn trong h thng.
Bnh cha v cm np - xut (LPG Tank and Multi Valve)Nhin liu LPG trn t thng c nn trong b nh cha vi p sut
khong 10 bar. B nh cha nhin liu kh thng c dng tr v c 2 u h nh bn
cu. i khi b nh cha cng c dng h nh xuyn. Dng b nh cha ny ging ht
bnh xe, thng c s dng i vi ng c lng nhin liu v n c th t vo
khng gian ca bnh xe d tr.
Nhn chung, trng lng ca b nh cha ln v phi ch to bng thp dy
khong vi mm m bo an ton cho t v hnh khch c bit l khi xy ra tai
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ln. Ngy nay, trn th gii c mt s nc tin tin nh: Nga, M, Nht bt
u sn xut v s dng loi bnh cha LPG bng nha tng hp Plastic c li l
li thp. Loi vt liu ny rt nh d s dng v vn chuyn, nhng hin nay githnh tng i cao. Trc khi xut xng cc bnh cha LPG u phi qua th tc
th nghim, kim tra v chng nhn t yu cu an ton nh i vi cc loi bnh
cha c p sut cao thng thng khc. Php bnh cha LPG trn t phi qua
th nghim hai bc: bc u di p xut tnh 30 bar, bc th 2 th va chm
(50km/h v dng) p sut 11 bar trong bnh cha.
LPG c np vo bnh ti trm np, thng qua chi tit u np (Refulling
Point) c ch. Trn th gii thng thng c hai dng: vn vo bng ren hoc bng
cn p ni vi ng ng np ca trm np, khi np LPG ch c php np vo
80% dung tch bnh cha, phn th tch cn li d tr cho p sut bo ho ca
pha hi c th c, do nh hng ca nhit bn ngoi.
H. 2-17. Thng nhin liu LPG
Trn ng np vo cn c van ngc v van kho bng tay. Van ngc c
tc dng ch cho gas i theo mt chiu vo bnh m khng cho gas thot ra bng
ng np ny. Van kho tay c tc dng ng ca np mt cch ch ng, rt cn
thit trong trng hp cn bo dng van ngc v u np c ch, chi tit ny
c ch to trn mt cm. Cng trn cm ny c ng xut gas ra khi bnh cha
v c cc van an ton nh: van x t ng khi gas np vo y qu mc cho php
hoc s tng qu p sut bo ho hi do nhit tng t ngt, van ng t ng
khi dng gas thot ra vi tc nhanh (khi xy ra s c), van kho bng tay ng
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xut gas ra khi bnh c th c lp gas lng trongb nh khi cn sa cha bo
dng h thng. Cc chi tit ny c ch to trn chung mt cm gi l cm np -
xut nhin liu LPG.Cm np xut thng c hnh trn v ch to cng mt ng h ch th mc
LPG lng trong b nh. N c chia thnh cc mc 01/42/43/44/4. Cm
np xut ca tt c cc hng u c bo v trong hp st kn, c mt knh trong
sut c ch th mc LPG pha lng trong bnh. Np hp c th tho c v c
g t roong cao su cho kn, trong hp ny c ng dn gi vo v dn gi ra
c lp. ng thng gi ra c a xung gm xe, phng trng hp c r
r cm np xut hoc nhng git LPG c th ng li hng np sau mi ln np
LPG, c gi thi ra ngoi v khng tch t trong khoang hnh l ca xe gy nguy
him.
H. 2-18. Cm van np xut ng dn LPG p sut cao.
ng ng dn LPG t b nh cha n b gim p ho hi l ng ng
chu p sut cao ti a n 2,4Mpa, nn thng n c ch to bng ng thau c
ng knh t 6 8 mm. N c th c un cong cho ph hp vi yu cu s
dng. ng ng c lp t di gm xe, cch xa ng ng x ca xe.
B gim p - ho hi(Pneumatic LPG Reducer)
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