NGHIEN cufu-TRAO D | NGHIGN c a u DONG LL/C HOC DAN DONG PHANH THUY KHf TR^N TO STUDYING DYNAMICS OF HYDRAULIC - PNEUMATIC DRIVE IN VEHICLE BRAKE SYSTEM IhS Vo Quoc Dai Trfldng Dai hpc Ky thuat Le Quy Ddn TOM TAT He thongphanh thuy Id mot nhUng he thongphanh sii dung rdng rdi tren d td tdi Idn vd cdc xe sieu Id he thong phanh sU dung ddn ddng ket hdp giUa thuy lUc vd nen Do vay, nghien cUu ddng lUc hoc cua he thdng ddn ddng ndy Id mot cdng viec phUc tap vd ddi hdi khoi lUdng tinh todn Idn SU dungphUdngphdp md phdng vdi cdc thdng so tap trung, gidi bdi todn bdng cdng cu Simulink cua Matlab de nghien cUu cdc qud trinh xay he thong phanh thuy khdng chi gidm dUdc khoi lUdng tinh todn md cdn mang lai cdc ket qud tin cay Cdc ket qud thu dUdc tU viec tinh todn Id thdi gian nap khi, thdi gian cham tdc dung cua he thong, TU nghien ciiu ndy, cd thexem xet sU dnh hUdngcua cdc thdng so ket cau den ddng lUc hoc ddn ddng cua he thong, dieu ndy cd y nghia quan trong nghien cUu vd gidng day chuyen ngdnh d td tai cdc trUdng Dai hoc d Viet Nam ABSTACTS Hydraulic - pneumatic brake system is one of the most typical one in heavy truck and very heavy truck Their character is combined hydaulic drive with pneumatic drive, therefore, studying dynamics of hydraulic pneumatic drive in vehicle brake system is complicated and invovle huge calculations Using ''Simulation with concentrated parameters" method with Simulink to study process that happen in hydraulic - pneumatic drive in vehicle brake system not only reduce amount of calculations hut also lead to acceptable result From the research, we could determine period of gas load process, brake - delay time, etc or study system structure parameters effect on dynamics of the system, that are important meaning in university teaching and studying in Vietnam TAP CHI CO KHI VIET NAM • Sd 12 (Thang 12 nam 2011) NGHIEN cufu-TRAO D | l.DATVANDE Cdc phflpng trinh Iflu IflOng He thdng phanh thuy Id mpt nhflng he thdng phanh dien hinh cua cdc loai d td quan sfl, dac biet Id cdc d td hang nang Dac thu cua he thdng phanh ndy Id sfl ket hpp gifla thuy Iflc vd nen, dd viec nghien cflu tinh todn ddng Iflc hpc ddn ddng phanh thuy tflOng ddi phflc tap cung nhfl ddi hdi khdi Iflpng tinh todn Idn Dung phflpng phdp "md phdng vdi cdc thdng sd tap trung" cung vdi sfl hd trp cua cdng cu Simulink Matlab de nghien cflu ddng Iflc hpc cdc qud trinh xay he thdng dan ddng phanh thuy nham xdc dinh thdi gian cua cac qua trinh nap khi, thdi gian cham tac dung cua he thdng vd thdi gian xa cung nhfl nghien cflu sfl dnh hfldng cua cac thdng sd ket cau den chat Iflpng phanh cd nbieu y nghia khai thdc, sfl dung vd thiet ke cai tien cdc he thdng phanh thuy hien c6 NOI DUNG 2.1 Co sd ly thuyet Ddi vdi phan dan ddng thuy Iflc: cd the dung mpt md hinh Id md hinh truyen sdng, md hinh ddn hdi vd md hinh khdng ddn hdi Trong bdi bdo ndy, chung tdi sfl dung md hinh ddn hdi de giai bdi todn phan dan ddng thuy Iflc Trong md hinh ndy ngfldi ta coi Iflu IflOng chat Idng Qj di vdo he thdng dflpc chia thdnh phan: Qji^ Id Iflpng bu cho tinh ddn hdi cua he thdng vd Q^ Id Iflpng chat Idng thflc hien cdng hflu ich Qi = Q2 + Q dh (1) Theo md hinh ndy, he thdng phflong trinh md ta ddng Iflc hpc cua phan dan ddng thuy Iflc gdm dang phflong trinh tflOng flng vdi cac qud trinh xay he thdng: Cdc phflong trinh chuyen ddng cua cdc chi tiet ddng he thdng Phan dan ddng nen: de md ta cdc qua trinh ddng Iflc hpc cua ddng nen can phai xay dflng dflpc cac bieu thflc tinh todn lien he gifla cac thdng sd trang thai p, V, T, m vdi cac thdng sd ket cau cua dan ddng Do mflc dp phflc tap cua cac qua trinh xay he thdng dan ddng nen nen cho den van chfla tim dflpc bieu thflc toan hpc chinh xdc md ta hdm Iflu Iflpng Trong tinh toan van phai sfl dung cac cdng thflc kinh nghiem hoac cac cdng thflc gan dung Trong khudn khd bdi bdo, chung tdi dung cdng thflc thflc nghiem ve hdm tieu thu (p(a) cua H.(|) Mex/iiOK: (pia) = A i - o B-a (2) Trong dd: o = p^p^^ Id dp suat khdng thfl nguyen chinh bang ti sd gifla dp suat dau vd dp suat dau vdo cua mpt phan tfl; A = 0,654; B = 1,13 Id cac hang sd thflc nghiem Sau cac bien ddi cudi cung, phflpng trinh tinh Iflu Iflpng di qua tiet Iflu cd dang: ^ w dm l-cr — = 0,654 / / / v , ^ RT L - dt (3) De md phdng ddng Iflc hpc dan ddng phanh thuy O day chung tdi sfl dung phflpng phap md phdng tap trung dflpc thflc hien theo cac nguyen tac sau: The tich mdi chat cdng tac chfla phan tfl dxicic coi Id tap trung tai mpt dung tich Dung tich ndy cd the Id khdng ddi hoac bien ddi qua trinh he thdng ldm viec Sflc can ddng chuyen ddng cua cac phan tfl dflpc ky hieu tap trung bang mpt tiet Iflu, tiet Iflu ndy cd the cd tiet dien khdng ddi hoac cd the thay ddi Dac trflng sflc can ddng qua mdi phan tfl Id he sd cdn ddng ^ Cdc phflong trinh ddng chay cua chat Idng he thdng TAP CHI CO KHI VIET NAM - Mdi ghep gifla cac phan tfl gpi Id diem nut • Sd 12 (Thang 12 nam 2011) NGHIEN cufu-TRAO D | Mdi ghep gifla cac phan tfl gpi Id diem nut long dai sd Iflu Iflpfng mdi chat di vdo vd khdi diem nut tai thdi diem bat ky bang II III (4) nil I-finh 1: I.ii'ii lUdiig di qua diem nut Tu hinh ta cd phflOng trinh Iflu Iflpng tuc thdi di qua diem A nhfl sau: ffl - ftU- ffl ffl ã*ã /ôô; = (5) Khi xay dflng he cdc phflOng trinh vi phan md td he thdng, ta sfl dung cdc gia thiet sau: Nhiet dp he thdng dan ddng phanh thuy vd sudt qud trinh ldm viec deu bang vd khdng ddi Viec ddng md cac van dieu khien dflpc coi Id tflc thdi (khdng nghien cflu qud trinh qud dp gifla cdc trang thai cua van) Khi tinh todn cdc phan tfl cd the tich thay ddi phan nen (nhfl cdc khoang khdng cua xylanh chinh hoac bau phanh), cd the bd qua: he sd ma sat gifla pittdng vdi thdnh xylanh (hoac ma sdt gifla mdng cao su cua bau phanh vdi thdnh bau phanh); ma sdt nhdt; khdi Iflgfng cua pittdng, mdng cao su cua bau phanh, can day t^9 nhdt, khdi IflOng rieng vd nhiet dp cua chat Idng phan dan ddng thuy Iflc vd IflOng khdng hod tan chat Idng khdng thay ddi qua trinh khao sat Khdng cd rd ri he thdng 2.2 Thiet lap be phflong trinh vi phan Dfla vdo ca sd ly thuyet da chi va phan chia sfl ldm viec cua he thdng phanh thuy thdnh che dp: che dp nap khi, che dp dap phanh vd che dp nhd phanh Ta se xay dflng dflpc cac he phflong trinh vi phan md ta he thdng phanh thuy tren xe MAZ - 537: a Che dp nap So dd khdi cdc phan tfl qua trinh nap dflpc md ta tren hinh MNK — ^ Binh - ^ Binh - ^ T6ngVP U 1 ^ V r KumoOC I Binh RMl nl6 Binh RMl Hinh 2: Sd khdi he thdng ddn ddng phanh xe MAZ - 537 che nap TAP CHI CO KHI VIET NAM V S l (Thang 12 nam 2011) NGHIEN cufu-TRAO D | Vdi so khdi tren, ta cd so dang nut dflpc md ta tren hinh V VP VTV ^ (ixf)i Yl ([^2 J> ^-^ ^'^ E? ' YJ '"^^ V'x Y3 Y5 (Mf>5 (Mf)4 {^^ "" (l^f)6 ^'^ """"^ Y4 Y6 \'2 V HI VR, Hinh 3: Sd nut tinh todn mach qud trinh nap Trong dd: Vj the tich qui ddi ve binh chfla thfl nhat; V^ the tich qui ddi ve binh chfla klii thfl hai; V.j.yp the tich qui ddi ve tdng van phanh; Vypj^ - the tich qui ddi ve van phanh rpmodc; Vj^j the tich qui ddi ve binh chfla Idii thfl nhat cua romodc; Vj^2 - the tich qui ddi ve binh chfla thfl hai cua rpmodc; [ii (i = 6) he sd Iflu Iflpng cua cac phan tfl tflpng flng; f (i = 6) - tiet dien ngang dfldng ong cua cdc phan tfl tflpng flng Tfl sP dd nut d tren ta xay dflng be phflpng trinh vi phan md td che dp nap (6) P^-P\ ^ i./i ^\i, Po A Bp, - A M 2/2 V P\ ^ \^ 3/3 ^.h Pi A P^- Pi Bp,- -Pi P2- Pi P\-Pi B p^- ^ 3/3 V?/, Pi ^ -PA - ^ 5/5 V,i, M JA V Pi (^ ^'' Bp, -PA ^ 5/5 V P4 A A - -PS Bp, -Ps V 1^ Jb ^,h Ps A Ps- -Pe ''' ^''' Bp,-p, k dt Bp,- -Pi Pi- PA Vjyp UPjyp Bp, -PA k dt • 1^ 4./^4 V,l, Pi A BP2 -Pi ^ dp _^i^^0 P-, k dt M 2./2 V,l, P\ A Vypn api'pn -Ps PAPA A k Bp, -Ps (6) =0 Ki 4?«i _ k dt Ps- -Pt B Pi- Pk V dt =0 ^2=0 k dt b Che dp dap phanh: Phan dan ddng nen xe dau keo MAZ 537 che dp dap phanh dflpc md ta bang sP nflt vd he phflong trinh vi phan (7) P2 ((^f)3 V3 ffl" Iff — ; Y3 (^f)5 (Mf)7 V5 *^(^f)4 Y2 _ (|if)6 f^^ X (Mf)8^ Ml -III \ ^6 V4 Hinh 4: Sd nut mach ddn dong phanh chinh xe keo TAP CHI CO KHI VIET NAM V Sd 12 (Thang 12 nam 2011) NGHIEN ClJfU - TRAO D | > 1^ ,^''' , ^ > " 'i C Zl }4 D.C 0.2 O.B 0.1 il.« ca T l o l ginn ir.| Hinh