SCIENCE ft TECHNOLOGV DEVELOPMENT, Vll.U, Nl.Kt - M i l Anh hirong hinh dang bu6ng chdy den cong sudt va phat thai cua dOng co Diesel Vikyno RV125-2 Nguyin Le Duy K h i i ' Nguyin s i c Khiinh Hu>ng' ' Twang Bgi hpc BSch Khoa, OHQG-HCM =^Cong ty TNHH Mercedes-Benz Vi$t Nam fBai nh4r ngiy 12 thdng 01 nam 20 IS hoin chinh si>a chOa ngciy 08 Mng 03 nam 201S) TOM TAT 5S5^ Bdi bdo trinh bdy nghien cuu dnh hatdng hinh dgng budng ch^ den cdng suat vd kht thdijrin dgng ca diesel phun tnfc tiep, budng chdy thing nhdt VIKYNO RVI25-2 bdng ph^n mim md phdng KIVA-3V Trong nghiin dtu nc^, dg sdu budng chdy, dudng kinh day buong chdy va dudng kinh mi^ng budng chtiy dugc ihcty dil, y^ vdn gl^ nguyen ty si nin dgng ca Ket qud nghiSn citu chi rdng, tdng dudng kinh mi^ng budng chdy co tdc d^ng tot nhdt Cy thi dudng kinh mi^ng budng chdy thay ddi tir 3.98cm len 4.7cm, cdng suat tdng 6.22% nong dg NQx gidm 0.85% Tuy nhien bd hdng sS tdng 45.83% Titkhda: Hinh dgng buong chdy KIVA-3V, mdphong, dgng ca diesel RV12 5-2 I DATVANDfe Tu doi d ^ dgng co diesel khmg ngimg duQic cai liln vd phdt triln dl ngdy cdng hodn thi^ va dat ndng suat cao T^i Viet nam, Cdng ty Trdeh nhi$m hfhi ban Dgng co va May nmg nghi#p Mien Nam (SVEAM) Id mot nhung cflng ty hdng dau lihh v\rc co mdy dflng lire vd mdy nflng nghi#p Trong nhung ddng san phdm ciia SVEAM, dong co diesel VIKYNO RV125-2 chilm ti Ion nh4t, khoang 30% long san lirgng dwig co diesel hdng ndm cua cong ty [1] Tuy nhiai, dgng ca dugrc san xu^t dya T r m 1HZ tr€n ban quyen ciia Kubota cdch day dd 20 nam, che t^o dieo cong ngh€ cu n ^ nhfing ddc tinh ciia dflng CO kha thdp, can phdi cai Ihi^n de ddp iing du^rc myc tieu xuat khau cung nhu ndng cao till truong nuoc Mot nhfing giai phdp khd thi Id cdi tiln hlnh d^ng bu6ng chay dpng ca nhdm tdng cuong qud trinh h6a trfln nhien li§u, tir giup qud trinh chdy hodn thi^n, Idng cflng suat vd giam khf thai Trong bdi bdo ndy, tdc gid dd sii dung phucmg phdp mfl phong voi phdn mim KIVA-3V de nghiSn cuu anh hucmg cua cdc thdng so hlnh hpc T^P CHl PHAT TBIEH KHftCH, TAP 18, SO K2- 2015 ciia bu6ng chay d^n d(lc tinh dOng ca Vikyno Bang I Thflng so dflng co xy lanh Vykino RV125-2, tit d6 d i xuat hlnh ddng bu6ng chdy t6t RV125-2 nhit c^ the, PHU'ONG P H A P S ThAng sh GUni Nhien ti^u Diesel S6 xy lanh VI$c nghi€n cihi dnh hudng cua hlnh d^ng buong chdy trfin d$ng co diesel phun tryc tilp du9c th\rc hi$n bibig phan m i m md phong CFD ba chieu KIVA-3V Day Id diuong trinh mfl phflng ma n g u ^ md dir^c phdt t r i ^ bdi Phflng thf Duimg kinh x Hanh trinh piston 624 cm' Dung tich Ty so n£n 18:1 So Iwmg xd pip n^p, thai iTcrt Kifiu xy lanh nghidm Qu6c gia Los Alamos (Hoa Kj'), d\ra tr£n H^ thong phoi cdc phuong trinh bfto todn vd chuyin hfla ve nhi?t, ThM diem ph&i Idtil lu9ng vd mfl men gifia cdc pha khf xy lanh [2], Ddng chdy rdi dugrc md p h ^ g bdng md hlnh Re-Nonnalisation Group (RNG) k-e cai tiln, DOHC Thai d]£m xi^ p^p n^p ISS-BTDC dong Thcri diem xO pap xa ma I30°ATDC Kim phun duoc phdt triln bdi Han vd Reitz, 1995 [3], Mfl Kieu kim phun hlnh xi t d tia phun Wave Breakup dupc phdt triln Sd 16 tia X dicn lich bdi Liu et al, [4] Bfin c?nh KIVA-3V cfln sd x mm Khoi lu^ng Bosch CPI l350Bar X 0.2867e-4cm' 0274g/15dO phun/gi^c quay dyng rit nhilu cdc md hlnh phy khac de md phong cdc qud trinh xdy nhifin lifu phun vdo buong Viec tao mfl hinh ludi dflng co de lien hdnh dot cho din bit diu bfin Ifia nhu mfl hlnh bien mfl phong rdt quan trpng Viec xdc lap bifin dang dang cua h^t nhifin li^u xet din hfi so can chuyin hhih hoc ciia buflng chay tren dinh piston duoc dflng cua h^l buclng chdy, mfl hlnh chdy tre thyc hien dua vdo ban ve thilt ke tir nhd sdn xuat Shell [5], md hinh chdy chlnh theo thdi gian d$c Vykino trinh bdy tr^n hlnh trung ciia Abraham et al [6], D l khao sdt sy tdc dong cLia cac thflng s6 phun den d nhienj mfli 094 -0.2 tmdng, KIVA-3V sd dyng md hlnh Zel'dovich cho qud trinh hinh thdnh NOx (Y.B.Zel'dovich, 1946, [7]) vd tfnh todn sy hlnh thdnh bo hflng cung nhu qua trinh fl xi hfla bo hong dugc md phdng bdng md hinh bfl hong budc ciia Foster (N.L.D.Khai; N.Sung, 2011, [8]) J T i \ LU'6l VA T H N G S O M O PHONG Bang trinh bdy cdc thdng sd chfnh cua ddng CO VIKYNO RV 125-2 Hinh ! Ban ve thiet ke piston Vykino RV125-2 Sau xdc dinh cdc thong sfl cdn thilt, ta Ihu dupc md hmh ludi ciia d$ng co Vykino RV125-2 Tpang103 SCIEMCE » TECHNOLOGY DEVELOPMEHT, Vel.18, No.KZ - 2015 K T QUA VA THAO LUAN nhu Hhih vdi gdc mfl phdng 90° Ludi md phdng dupc chia 26 phdn theo phuong tilp tuyin, 24 phan theo phuong hudng kinh, 24 phdn theo phuong dpc true, vdi tflng cdng 24037 d Iinh todn pit long d diem diet dudi Thdi gian trung binh hodn tat mot lan mo phdng Id khodng gid t r ^ mdy vi tinh trang bi vi xu ly Intel Core2 Duo E7400@2.8GHz Theo Yu Shi et al [9], ba thdng sd hinh hpc cd anh hudng Idn den qud trinh chay ciJa nh ien lieu cung nhu cdng sudt vd phdt thai cua dpng co Id dp sau budng diay (pip-height), dudng kinh day budng chdy (bottom bowl diameter) va dudng kinh buflng chdy {bowl diameter) Qud trinh mfl phdng dupc th\rc hien theo hinh dang budng chay khac nhu Hinh de ddnh gia anh hudng ciia timg Ihong sd hlnh hpc rieng biet: Tang dp sdu, tdng dudng kinh ddy va lang dudng kinh mieng buflng chdy nhdm de xudt dang buong chdy hgp li cho phep Khi thay dfli hinh dang, dieu co bdn Id ty sfl nen ddng co phai dupc giiJ khdng thay doi, nhu Irinh bdy Bang Cdc thflng s6 mo phdng duoc trinh bay Bang 3, so vdng quay ddng co dupc giit khdng dfli Id 2400 vdng/phiit Hinh Mfl hinh hidi buong dit pit tong Vykmo RV125-2 Bdng Thong so hlnh dang buflng chay ban ddu va budng chdy d3 thay ddi huih dang ^~^ Buong chiy ban dau TSng d6 sSu Ting ducmg kinh diy Tingdirimg kinh micng Dqs&u (cm) 0,791 1.043(32%) 791 791 Dir&ng kfnh day (cm) 174 174 t^S92(26%) 174 fiirfrng kinb mi^ng (cm) 98 98 98 4.70(18%) Bang Thdng sd qud trinh mfl phdng ThAng sd Th6ng so hinh hgc mo phong (thscct) T6c dp d$ng CO 90.0° Thai diem xil p ^ nap dorg (IVC) i35degBTDC_kynan Then diem xii pip x i mcr (EVO) l30degATDC_ky chiy N h i ^ d$ thinh xy lanh Nhift dinh Piston Nhi«t nip quy lat Hinh dang buong chiy Khoi lircmg phun Thai gian phun (goc phun) Nhifn li^u d$c ining Nhtft nap tai IVC Trail 104 G i i tri 2400 v6ng/[A0t 400K 400K 400K Theo hinh 4-1 0274 g (80% tai) 9" CI4H30 313K TisS nCn 16 33 16 32 16 33 16 33 TjP Cil nil IWEIIWWCW, TiiP H, «0 H - 2015 ric quay Irifc khuju deg Hinh Buong chdy ban dau vd cac dgng buong chdy da dupc thay doi Qua mfl phong, chiing ta cfl the nghidn cuu Hinh Do thj nhi^ trung binh xy lanh Ihay doi hinh dgng buflng chay Tir hai thi trai cho thay tang dudng kinh day va tdng dudng kinh mifng budng chay thi cd tac dpng ciia hinh dgng hinh hpc ciia buong chdy s\r khde biet ro ret ve dp sudt va nhiet dp trung bhih •den cflng suat vd d nhiem mdi trudng tren dpng co xy lanh so vdi budng chay ban ddu Cu the, nghien ciiu Do thj ap suat trung binh vd nhi^t dp tdng dudng kinh mieng buflng chay bdng 50% Irong xy lanh l^i cac gdc quay true khuyu Iheo cdc dudng kinh pit-long thi dp suat cue dai tdng hinh dgng budng chdy khac dupc the hi^n 4.85%, dong thdi nhifit dd cue dai cung tdng tren Hinh vd Hinh 3.07% Cdn tang dudng kinh day budng chay bdng 80% dudng kinh budng chay thi dp suat cue dai giam 4.65%, dflng thdi nhiet cue dai cung gidm 5.2 Wo Dfli vdi dang buflng chdy tang dudng kinh mieng, vi tri tac dflng ciia tia phim nhien lieu ien vdch budng chay bi thay dfli, hdnh trinh tu ciia tia nhien lieu budng chay tang len, lucmg nhien li$u bdm vdo thdnh budng chay it, su hda udn vd Iflc dp xody 16c cua hdn hpp khdng nhifin lifu tdng (Hinh 6) Vi su hoa trpn nhien lifu - khflng tflt hon vd tdc dp xody 16c cua hdn hpp tang dan den thdi ky chdy hda trpn trudc xdy mdnh lift hon, keo theo sy gia Idng ciia dp suat va nhift dp cue dai xy lanh Cdn d dgng budng Coc