chuong7 he thong dieu khien chay tu dong

7/29/2019 Chuong7 He Thong Dieu Khien Chay Tu Dong

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He thong ien than xe & ieu khien t ong tren Oto Trang 213

CHNG 7: IEU KHIEN CHAY T ONG BANG

IEN T - CRUISE CONTROL SYSTEM (CCS)

7.1. KHAI QUAT VE HE THONG CHAY T ONG7.1.1. Vai tro cua he thong ieu khien chay t ong

He thong ieu khien chay t ong (CCS) duy tr xe chay tai mot toc o dolai xe at trc bang cach ieu chnh t ong goc m bm ga, do o ngilai khong can phai gi chan ga. He thong CCS ac biet co ch khi lai xe

lien tuc khong ngh trong nhieu gi tren ng cao toc hay ng xuyenquoc gia vang ngi, do ngi lai co the tha chan ga ap ga va xe se chay mot toc o khong oi cho du la len hay xuong doc. Nh co CCS nhngchuyen hanh trnh dai se t gay met moi hn. He thong CCS c ap dungnhieu tren nhng oto My hn nhng oto Chau Au, bi v nhng con ng My rong ln hn va noi chung thang hn.

Vi s phat trien khong ngng cua giao thong, he thong CCS ang trthanh hu ch hn, nhng oto i mi tng lai se c trang b CCS, no secho phep oto cua ban i theo oto pha trc no trong mot oan xe nh lientuc ieu chnh tang toc hoac giam toc e bao am mot khoang cach antoan. Trong mot vai trng hp, he thong CCS co the gop phan giam suattieu hao nhien lieu bang cach han che o lech cua bm ga.

7.1.2. Thanh phan cua CCSMot he thong CCS bao gom he thong ong m bm ga va mot he thongieu khien ky thuat so nham duy tr mot toc o oto khong oi trong nhng

ieu kien ng sa khac nhau. The he ke tiep cua he thong CCS ien tco the se tiep tuc s dung mot moun rieng le, tng t nh he thong angs dung hien nay, nhng c chia se d lieu t ong c, he thong phanhchong ham cng ABS, va he thong ieu khien hop so. He thong CCStrong tng lai co the bao gom cac cam bien raa e anh gia mc o tiepcan vi cac xe khac va ieu chnh toc o nham duy tr mot khoang cachkhong oi tuy nhien gia thanh can phai giam manh mi co the ng dungrong rai.


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Hnh 7.1 S o bo tr chung cua he thong CCS tren oto

7.1.3. Cach s dung he thong CCSHoat ong cua he thong CCS c ieu khien bi cong tac chnh, cac congtac ieu khien, ban ap ga va ban ap phanh. Thiet ke cua cong tac ieukhien khac nhau tuy theo kien xe. Hoat ong cua cong tac ieu khien CCSc thiet ke cho xe TOYOTA CRESSIDA nh sau:

Cong tac chnh va cong tac ieu khien tren moi loai xe khac nhau. Chungco the khac nhau ca ve thiet ke lan v tr lap rap nhng ve c ban thnguyen ly hoat ong giong nh tren xe TOYOTA CRESSIDA.

Cac nut chc nang cua cong tac ieu khien- ON-OFF: Cong tac chnh- SET/COAST: at toc o- Phuc hoi (RESUME): Khi he thong CCS ang hoat ong, neu no b

tam ngat do ban ap phanh, nut RESUME ra lenh cho CCS ieukhien oto chay tr lai toc o trc o a cai at.

- Tang toc (SET/ACCEL hay ACC)


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7.1.3.4. Phuc hoi lai toc o at trc:Bat cong tac RESUME/ACCEL se phuc hoi lai toc o at trc neu no tamthi b huy bo nh cac trng hp 1 2 3 4 - 5 trong khi toc o xe

khong giam xuong di 40Km/h. Khi tat cong tac chnh va cac trng hp6 7 th CCS se huy vnh vien toc o at trc. Neu lai xe muon phuc hoihoat ong CCS th phai at lai toc o trong bo nh bang cach bat cong tacchnh va lap lai thao tac at toc o nh mo ta tren.

7.2. CAC YEU CAU VE TNH NANG CUA CCSCac ac tnh cua mot he thong CCS ly tng bao gom cac yeu to sau:

Tnh nang ve toc o: Khoang ieu chnh toc o chenh lech so vitoc o thiet at trong khoang 0.5 1m/h. o tin cay: Mach c thiet ke e chong lai s vt qua ien ap

tc thi, ao chieu ien ap, va s tieu ph nang lng cua thiet bc han che mc thap nhat.

Cac phien ban ng dung khac nhau: Bang cach thay oi EEPROMthong qua mot seri d lieu n gian hay mang MUX, phan memCCS co the c nang cap, va toi u hoa cho cac kieu xe cu the.Nhng kha nang bien oi nay thch ng vi nhieu kieu cam bien,cac bo tr lc va nhieu pham vi toc o.

S thch ng cua ngi lai: Thi gian ap ng cua he thong CCS cothe c ieu chnh e phu hp vi s thch cua ngi lai trongpham vi tnh nang cua xe.

Kha canh an toan:

Thiet ke mot he thong CCS can phai tnh en mot so yeu to ve an toan. Vec ban phng phap thiet ke nham vao mach ieu khien bm ga nham

am bao c che x ly s co hoat ong ngay khi bo ieu khien vi mach hayc cau chap hanh h hong. Mach ien t an toan se cat cac bo tr lc ieukhien lam cho cac tay on ieu khien bm ga mat tac dung mot khi congtac phanh hay cong tac hanh trnh c kch hoat, vi moi tnh trang cua boECU hay cac mach ban dan cua bo ieu khien (Vi gia nh ket cau c khcua bo chap hanh trong tnh trang tot).

Cac van e khac lien quan en an toan bao gom cac chng trnh do tmtnh trang van hanh khong bnh thng va ghi lai cac d lieu nay vao bonh e phuc vu cho cong viec chan oan h hong sau nay. Tnh trang hoat


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ong khong bnh thng, chang han nh toc o xe khong on nh hay tnhieu ieu khien b ngat quang. Cong viec kiem tra co the c tien hanhtrong thi ky chay xe lan au va trong bat ky thi iem nao luc xe anghoat ong e xac nh mc o hoan chnh cua he thong ieu khien, tnh

trang hoat ong c the hien qua cac man hnh ch th cho ngi lai. Tnhtrang h hong nghiem trong nhat la s tang toc khong kiem soat c.Theo doi lien tuc tnh trang cua bo ECU va cac bo phan chu yeu khac segiup han che kha nang h hong nay.

7.3. HOAT ONG CUA CCSHe thong CCS bao gom: Cam bien toc o xe, cac cong tac, bo chap hanh

va bo vi x ly (bo CCS ECU ieu khien chay t ong). Bo ieu khien senhan tn hieu t cong tac ieu khien chnh, bo cam bien toc o va cong tacthang. Neu he thong ang s dung bo cam bien v tr cum tr lc hoac v trcanh bm ga, tn hieu cua no se c gi en bo ieu khien. Mot machien ong ho se thay oi tn hieu xung tren km thanh tn hieu xung trengiay - Hz (bien oi A/D). Mach tch hp bo kch thch va logic (IC) cchia lam 2 mach ien: mot mach se lu tr tan so c thiet at, mach khacse giam sat tan so cua bo cam bien toc o. Hai tan sonay se c so sanhvi nhau bang bo ieu khien. Neu tm thay s khac nhau gia 2 tan so,ECU gi tn hieu ieu khien en c cau chap hanh e ieu chnh v tr canhbm ga duy tr toc o oto gia tr thiet at.

Co hai loai c cau chap hanh: Loai dan ong chan khong va loai motbc, ngay nay chu yeu la dung loai chan khong, tuy nhien xu hng tnglai se s dung nhieu loai mo t e ieu khien toc o xe chnh xac hn.

Hnh 7.2 S o CCS dan ong bang chan khong

ECU

ong c


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Hnh 7.3: He thong CCS dan ong bang mo t bc

7.4. NGUYEN LY IEU KHIEN7.4.1. S o nguyen ly

He thong CCS hoat ong theo nguyen ly ieu khien hoi tiep (Close-loopcontrol), s o nguyen ly the hien nh sau:

Hnh 7.4 S o ieu khien CCSTn hieu au vao chnh yeu la toc o theo y muon cua ngi lai va toc othc cua xe. Cac tn hieu quan trong khac la s ieu chnh Faster-accel/Slower-coast cua ngi lai, Resume, On/Off, cong tac phanh, va tnhieu ieu khien ong c. Tn hieu au ra chu yeu la tr so cua bo tr lcieu khien bm ga, en bao ON cua CCS, nhng ch bao phuc vu bao

dng va nhng thong tin gi ve bo lu tr phuc vu chan oan h hong.

ECU

ong c

Tn hieu

at trc

X ly tnhieu vao

C cauchap hanh

C caudan ong

V trbm ga

Cam bientoc o xe


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7.4.2. S o mach va s o khoi:S o khoi:

Hnh 7.5 S o he thong CCS

E

CUIEUKHIENCHAY

T

ONG

Khoa ien

Cong tac chnh

Cam bien toc o

Cong tac ieu khien

Cong tac phanh tay

Cong tac en phanh

Cong tac ly hp

Cong tac khi ongtrung gian

Giac kiem tra hay TDCL

Cong tac chan khong

ECU ong c va ECT

Van ieu khien

Van xa

Cong tacen hanh

BO CHAP HANH

en bao

ECU ong c va ECT

Van ien No.2 ECT

ECU O/D hay Relay

Van ien O/D (A/T)

Bm chan khong


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Hnh 7.6: S o mach ien he thong CCS tren xe TOYOTA CRESSIDA

Tn hieu au vao:Cam bien toc o la bo phan chnh yeu nhat cua he thong, bi v bo CCSECU o at toc o xe t bo cam bien toc o trong pham vi 1/32 (m/h). Moiday cap cua ong ho toc o hay s dao ong eu gay sai lech trong tnh

toan toc o. S sai lech trong tnh toan toc o co the c giam thieu bangchu ky o at. Cam bien toc o dan ong cho Microcontrollers TimerInput Capture Line hay Interrupt Line ben ngoai. Bo ECU se tnh toan toco xe t tan so cua tn hieu, bo cam bien va t c s thi gian ben trongECU. Tr so toc o cua xe se c cap nhat lien tuc va c lu tr trongbo nh RAM va c x ly bi chng trnh ieu khien toc o c s. Thongthng bo cam bien toc o la mot may phat xoay chieu n gian c bo tr

hop so hay cap truyen ong ong ho toc o. May phat xoay chieu nay taora mot ien ap xoay chieu vi tan so t le vi cam bien toc o vong va toc

ECU hayr le O/D

ECU hayr le O/D

Van ien O/D(A/T)

Cam bien toc o so2

Cam bien toc o so1

Van ien so 2(ECT)

Cong tac en phanh

en phanh

Ac quy

MAIN FL ALT FL AM1 FL

Cau ch STOP

Van xa

Van /khien

Bo chap hanh

ECUieu khienchay t

ong

Giac noi chan oan tong (TDCL)

Giac noi chan oan tong

Bm chan khong

Cong tac chan khong

May khi ong

Cong tac khi ong trung gian

Cong tac ly hp

Cong tac ieu khienMAIN

SET/COAST

RES/ACC

CANCEL

en bao 2

en bao phanh

Cong tac ph anh tay

Cau chGAUGE

Cau chGAUGE

Khoa ienSTT

IGACC

1

2

3

41

2

3


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o cua xe. Cam bien quang hoc tai au ong ho toc o cung co the c sdung. Thong thng cam bien toc o tao ra mot so xung hay chu ky trenmoi Km. Cung vi viec s dung phanh chong trt ABS ngay cang nhieu,tr so cam bien bo sung co the nhan c t bo cam bien toc o at tai boABS tai banh xe. D lieu ve toc o t he thong ABS co the thu c thongqua mang MUX.Tn hieu au vao cua he thong CCS co the la t moi cong tac do ngi laithiet at hoac nhieu tn hieu Analog khac c chuyen oi thanh tn hieuau vao dang Digital. Ngoai ra con cac thong so khac cung c thamchieu en, o la cam bien v tr bm ga, tnh trang cua ly hp hay hethong truyen lc. Cac tn hieu au vao khac s dung trong he thong CCS la

v tr bm ga, hop so, bo ly hp, tnh trang bo A/C, chan oan bo chaphanh, tnh trang ong c nhng tn hieu nay co the lay t mang d lieuMUX.

7.4.3. Thuat toan ieu khien chay t ongChng trnh ieu khien chay t ong c thiet lap da vao ly thuyetieu khien m Fuzzy Control, ngi ta co the thiet ke thanh cong mothe thong ieu khien t ong cho nhng oi tng co qua nhieu thong so

au vao tac ong ma theo ly thuyet ieu khien t ong co ien trc aykho long giai quyet noi. Tn hieu au ra rat on nh du cho tn hieu auvao co the bien oi a dang.

S van hanh cua chng trnh ieu khien:

Hnh 7.7: Thuat toan ieu khien ga t ong (PI Speed error control)

Bo vi x ly c lap trnh e o at toc o xe va ghi lai mc o chay theo trncua xe va va xu hng cua no la tang hay giam. Phng phap PI tieu chuan

tao ra tn hieu au ra P t le vi vi s khac biet gia toc o xe a c cai atva toc o thc cua xe (o sai lech) bi mot tr so t le Gain Block KP. Mot tn

Actual Vehicle Speed Value

Set speed

value+ Proportional

gain, Kp

- +ActuatorControl

Speed Sensor

IntergralGain, KI


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hieu KI c tao ra va bien ong len xuong theo mot t le phu thuoc vao o sailech cua tn hieu. Cac gia tr thu nhan KI va KP c chon e tao ra phan ngnhanh, nhng vi mot mc o khong on nh nho. He thong PI cong vao mc osai lech, v vay, neu toc o di mc toc o cai at nh trong trng hp xe lendoc trong thi gian dai, tn hieu sai lech se bat au gia tang manh e bu tr.Trong ieu kien chay xe tren ng bang phang, tr soblock KI co xu hngtien ve 0 v t co s sai lech theo thi gian. Trong lng xe, tnh na ng ong c,sc can lan, cac yeu to nay se xac nh bang so PI. Tom lai, phng phap PI chophep he thong phan ng nhanh trong trng hp leo doc ot ngot hay chayxuong doc.

Kiem soat tn hieu au ra:

Khi tn hieu sai c x ly, mot tn hieu a en bo chap hanh c tao ra em ln bm ga, gi v tr co nh hay giam bt bm ga. Bo tr lc c capnhat vi ac tnh c kh cua bo tr lc, co the en vai phan ngan cua giay. Tnhieu sai lech co the c x ly nhanh hn, v vay, tao ra thi gian cho vai gia trtrung bnh cua cam bien toc o xe.ieu khien bm ga co the la loai tr lc chan khong truyen thong hay motbc. loai tr lc chan khong, chan khong tac ong vao bo chap hanh c xara theo qui trnh x ly s co bat c khi nao he thong phanh tac ong vi muc

ch bo sung cho qua trnh ong cuon solenoid ieu khien bo chap hanh. Bo trlc kieu mot ien oi hoi s truyen ong ien t phc tap hn va mot vai ccau x ly s co c kh c ket noi vao he thong phanh.

7.5. CAC BO PHAN CHNH CUA CCS7.5.1. Cam bien toc o (Speed Sensor)

Hnh 7.8: Cam bien toc o loai cong tac li ga


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Chc nang cua cam bien toc o xe la thong bao toc o hien thi cho ECU ieukhien chay t ong. Cam bien toc o xe chu yeu la loai cong tac li ga, loaiquang hoc (diod phat quang ket hp vi mot transitor quang) va loai MRE (loaiphan t ien tr t). Cam bien nay lap trong ong ho toc o hay hop so. Khi too xe tang, cap ong ho toc o xe quay nhanh hn, bat tac cong tac li ga haytransitor nhanh hn, ngc lai khi chay toc o thap hn se giam tan socua tnhhieu toc o.a) Loai cong tac li ga:c dung vi bang ong ho loai kim, khi day congt met quay, nam cham cung quay. ieu nay bat va tat cong tac li ga 4 lantrong mot vong quay. Toc o cua xe ty le vi tan so cua xung ien ap ra.b) Loai quang hoc: c dung vi bang ong ho kieu so, no cung c lap

trong ong ho toc o.

Hnh 7.9: Cam bien toc o loai quang

Cap ong ho toc o lam cho a xe ranh quay. Khi a xe ranh quay, no ngat tiasang chieu le transitor quang t diod phat quang (LED) lam cho transitor quangphat sinh xung ien ap. Anh sang t en LED b ngat 20 lan khi cap ong ho toc

o quay mot vong do o tao 20 xung. So lng xung nay c giam xuong 4xung trc khi tn hieu c gi en ECU ieu khien chay t ong,Mot tn hieu 20 xung tren mot vong quay cua truc roto do transitor quang va axe ranh tao ra c chuyen thanh tn hieu 4 xung tren mot vong quay nh ECUong ho so va chuyen en ECU chay t ong.c). Loai MRE (phan t ien tr t)Cam bien nay c lap tren hop so hay hop so phu va c dan ong bang banhrang chu ong cua truc th cap. Cam bien nay bao gom mot mach HIC (mach

tch hp) gan trong MRE (phan t ien tr t) va mot vanh t.


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Nguyen ly hoat ong cua MRE:Khi hng cua dong ien chay trong MRE song song vi hng cua ng sct, ien tr se tr nen ln (va dong ien yeu), ngc lai, khi hng cua dongien va ng sc t cat nhau, ien tr giam en mc toi thieu (va dong ienmanh). Hng cua ng sc t thay oi do chuyen ong quay cua nam chamlap tren vanh t, ket qua la ien ap ra cua MRE tt thanh dang song xoay chieu.Bo so sanh trong cam bien toc o chuyen dang song xoay chieu thanh tn hieuso, sau o no c ao ngc bang transitor trc khi en ong ho.Tan so cua dang song phu thuoc vao so lng cc cua nam cham lap tren vanht. Co 2 loai vanh t (tuy theo kieu xe): Loai co 20 cc t va loai co 4 cc t.Loai co 20 cc t tao ra dang song 20 chu ky (20 xung trong mot vong quay cua

vanh t), con loai 4 cc tao ra dang song 4 chu ky .Trong loai 20 cc, tan so cua tn hieu so c chuyen thanh 20 xung trong moivong quay cua cua vanh t thanh 4 xung bang mach chuyen oi xung trongong ho toc o sau o no c gi en ECU. Mach au ra cua cam bien toc okhac nhau tuy theo kieu xe. Ket qua la tn hieu phat ra cung khac nhau tuy theokieu xe: co loai ien ap ra va ien tr thay oi. Mot so cam bien toc o khongi qua bang ong ho ma gi trc tiep en ECU.

7.5.2. Bo ieu khienYeu cau ky thuat cua bo vi x ly (ECU): Bo ECU s dung trong he thong CCSco yeu cau cao ve chc nang. Bo ECU phai bao gom cac yeu cau sau:

Chuan thi gian phai chnh xac e o at va tnh toan toc o. Tn hieu vao A/D Tn hieu ra PWM Ghi nhan thi gian tn hieu vao Ghi nhan va so sanh thi gian tn hieu ra

Cong d lieu (cong MUX) Bo phan ghi gi ben trong EPROM Cong nghe Low-Power CMOS


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7.5.3. Bo phan dan ong (Actuator)a) Bo dan ong bang chan khong

Hnh 7.10: Bo dan ong bang chan khong

Van ieu khien:

Bo tr lc hoat ong bang chan khong gom mot tam mang hoat ong bang lo xovi van cung cap, van nay c ieu khien bang solenoid. Khi he thong khong

s dung en, solenoid cua van ieu khien se la thng ong trong luc o,solenoid van thong hi se cho kh tri i vao. Mang cua bo tr lc va lo xo segian ra va goc m canh bm ga se khong c ieu chnh. Viec ong va mnhng van nay trong khi hoat ong se duy tr c viec thiet lap toc o dichuyen cua oto tren ng nh mong muon.Van xa:

Dung e dan ap suat kh quyen vao trong bo chap hanh khi he thong CCS bhuy bo. Van xa con ong vai tro nh mot van an toan neu van ieu khien b co

nh tai v tr cap chan khong do h hong. No dan ap suat kh quyen t van antoan e ong bm ga, do vay co the giam c toc o xe. Van xa nh vay baoam tnh an toan cao khi lai xe.


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Hnh 7.12: au day cap t Actuator en bm gaS o gom: Bo tr lc ieu khien gom co mang va cac solenoid ieu khien chankhong.He so xung va ieu khien he so xung:ECU gi mot dong ngat (tnh hieu xung) en van ieu khien vi tan so khoang20 Hz, bang cach thay oi khoang thi gian dong ien bat va tat (c goi la heso xung) se lam tang hay giam o chan khong trong bo chap hanh theo toc oxe.Khi dong ien bat trong khoang thi gian dai (he so xung cao) th van chankhong se m trong thi gian lau hn, o chan khong tang trong bo chap hanh,ket qua la bm ga m va toc o xe tang len.

Khi dong ien tat trong khoang thi gian dai (he so xung thap) th van khquyen se m trong khoang thi gian lau hn, o chan khong tang trong bo chaphanh, ket qua la bm ga ong va toc o xe giam xuong.

Toc o tangON

OFF

Toc o giamON

OFF

TOC O OTO TANGON ON

OFF OFF

TOC O OTO GIAM


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S hoat ong cua c cau chap hanh:Khi xe hoat ong toc o khong thay oi, tang hay giam toc van ieu khien vavan xa trong bo chap hanh hoat ong e ieu khien to o xe. Hoat ong va slien he cua cac van nay ng vi tng ieu kien lai xe c tong ket trong bang

sau:S PHOI HP HOAT ONG CUA VAN IEU KHIEN VA VAN XA

ieu kienCONGTAC

CHNH

BO CHAP HANHVAN IEU KHIEN VAN XA

Dong ien Dong ienVan chan

khongVan khquyen

Van khquyen

1. CCS tat Tat Tat Tatong M M

2. Cha at toc o BatTat Tat

ong M M

3. at toc o Batieu khien xung Bat

M ong M ong ong4. Chay tai toc o viche o CCS

Batieu khien xung Bat

M ong M ong ong

5. Tang toc vi congtac ieu khien Bat ieu khien xung BatM ong M ong ong6. Giam toc vi congtac ieu khien

BatTat Tat

ong M M7. Tam thi tang tocbang ban ap ga

BatTat Tat

ong M M8. Toc o xe cao hntoc o at trc


M ong M ong ong

9. Toc o xe thap hntoc o at trc Bat ieu khien xung BatM ong M ong ong

10. Huy BatTat Tat

ong M M11.Phuc hoi toc o xebang cong tac ieukhien


M ong M ong ong


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S o phoi hp toc o xe vi cac trang thai cua van ieu khien va van xa

b) Bo dan ong bang motor:Bo chap hanh gom mot mo t, ly hp t va bien tr, thc hien nhiem vu truye ntac ong ieu khien t ECU en bm ga tng t nh bo dan ong bang chankhong.

VANK

VANXA

ON

OFF

ON

OFF

TOCOXE

HUY PHUC HOI

GAUGE Cau ch

GAUGE

Cau ch

Cong tac phanh tay

en bao phanh

en bao 2

CANCEL

RES/ACC

SET/COAST

MAINCong tac ieu khien

Cong tac ly hpCong tac khi ongtrung gianMay khi ongCong tac chan khong

Bm chan khongGiac noi chan oantong

Giac noi chan oantong (TDCL)

ong

chay t

ieu khien

ECU

Bo chap hanhVan /khien

Van xaCau ch STOP

MAIN FL ALT FLAM1 FL

Ac quyen phanhCong tac en phanh

Van ien so 2(ECT)

Cam bien toc o so 1Cam bien toc o so 2Van ien O/D(A/T)

r le O/D

ECU hay

r le O/DECU hayACCIG

STTKhoa ien

GAUGE

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