Effect of engine parameters on turbocharger second law efficiency in turbocharged diesel engines

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1 h Annual (Inrnaonal) Conrnc on Mchancal Engnrng-ISME7 May -7, 7, Amrkabr Unvrsy o chnology, hran, Iran ISME7- Ec o ngn paramrs on urbochargr n urbochargd dsl ngns M Ghazkhan Asssan prossor, Frdows Mashhad Unvrsy,Iran m_ghazkhan@yahoocom MR Zangoo PhD sudn, Frdows Mashhad Unvrsy,Iran Mrzangoo@gmalcom A Darband MSc sudn, Frdows Mashhad Unvrsy,Iran al_darband7@yahoocom Absrac In hs papr a sudy o analyz h nlunc o ngn paramrs on scond law urbochargr cncy s nvsgad h analyss has bn prormd by mans o a our srok, our cylndrs urbochargd dsl ngn and ss hav bn carrd ou n consan spd wh drn loads In hs work xhaus spcs wr masurd and xrgy low o xhaus and urbn powr oupu has bn calculad hn urbochargr scond law cncy calculad h rsuls show ha hghr bmp, hghr xhaus prssur and mpraur, hghr quvalnc rao and hghr ngn spd ncras urbochargr Hghr scond law cncy o urbochargr mans hghr urbn work wh a spcc amoun o xrgy low o xhaus ha mans urbochargr d back n ransn condons could b mprovd by hghr ngn spd, hghr nl urbn mpraur and hghr ul-ar rao du o br avalabl work ransr bwn ngn cylndr and urbochargr Kywords: urbochargr, Scond law cncy, Dsl ngn Inroducon In ordr o ncras h powr oupu and o sav h nrgy, h urbochargd dsl ngns ar usually usd or auomov ngns [] Bu urbochargr lag occurs n hs ngns durng ransn condon such as a rapd acclraon or a suddn larg load applcaon, and hn rsul n a wors rspons prormanc han hos o naurally asprad ngn [] By adopng h urbochargd dsl ngn, h maxmum hrmal cncy s ncrasd, whl urbochargd vhcl has a wak pon o poor drvably undr ransn runnng condons whn h urbochargr dos no work cvly, spcally a low spd opraon and rapd acclraon by h conrol o ul-pump rack [] In gnral, h causs o h m dlay n h ransn opraon o a urbochargd ngn can b classd n hr groups: mchancal, hrmal and lud-dynamc phnomna [] In h rs group mchancal rcon and spcally h nra o h urbochargr and ohr roang lmns o h ngn ar ncludd Rlvan hrmo- and lud dynamc causs ar h mass and nrgy ransr procsss rom h xhaus valv up o h urbn and rom h comprssor oul o h cylndr Acually hs hrmo- and lud dynamc paramrs manly dpnd on h nra o h urbochargr and ohr roang lmns o h ngn So h spcc characrscs o h nrgy ransr bwn h cylndr and h urbochargr ar h man caus o h dlay n h urbochargr acclraon I s wll undrsood ha h nrgy ranspord by h xhaus gass arrvs a h urbn vry quckly durng any ransn opraon [] Nvrhlss, only a racon o hs nrgy s convrd no mchancal work and ransrrd o h comprssor, snc h largs par o h hrmal nrgy s mployd n ovrcomng h urbochargr roor nra o acclra h nra o h urbochargr and ohr roang lmns o h ngn s h only drn bwn sady sa and ransn condons n urbochargd dsl ngn as J Bnajs -al srss" s wll undrsood ha h nrgy ranspord by h xhaus gass arrvs a h urbn vry quckly durng any ransn opraon" [] In h pon o urbochargd dsl ngn, h scond law cncy o urbochargr n sady sa condons s mprovd ha mans br nrgy ransr bwn ngn cylndr and urbochargr rsuls br ovrcomng o urbochargr nra n ransn condon ha s why n hs rsarch h hghr sady sa rsuls ar usd o xplan as a rason or br ransn urbochargr bhavor o dsl ngn Quck changs n rack poson do no rsul n nsananous rspons o h urbochargr, du o s nra and comprssbly o h xhaus gas wh h ngn hus h ar-ul rao quckly dcrass o a vry low valu and ncompl combuson occurs n h mxur; alhough much quany o ul can b rapdly njcd no h cylndrs, h urbochargr s slow o rspond and provd a corrspondng ncras n ar or h combuson [] Consqunly urbochargr has a poor snsvy undr ransn runnng condon and urbochargr dos no work cnly h am o hs work s o nd h c o ngn paramrs on urbochargr urbochargr xrgy analyss s a powrul ool o nd

2 h rasons o h ra o urbn work n urbochargd dsl ngns In h prsn work alhough h varaon o ngn paramrs and urbochargr scond law cncy, n h sady sa condon hav bn nvsgad Bu h varaons o sady sa rsuls ar usd o dscuss on ransn urbochargr bhavor Exprmnal s rg Fgur shows a schmac dagram o h s rg and masurng sysm OM urbochargd dsl ngn () was usd n prsn work Engn characrscs ar gvn n abl Engn s urbochargd by a urbochargr (), () quppd wh a was ga (9), suppord by Borg Warnr Company o convr asprad ngn o urbochargd dsl ngn h s rg s quppd wh a kw DXF Hnan & Froud hydraulc dynamomr () A Pln-RE gas analyzr () masurs unburnd hydrocarbon as C 6 H, CO, CO and O h xprmnal apparaus s composd rom AVL- smok mr (), hrmocoupl yp K (6),(7),(8),(9) nrac o a PC(), volumrc ul mr(), ar mr (surg ank and orc manomr) (),() prssur gags (),(6), (7) and lcrcal ngn spd mr (8) _Engn _Compur and nrac _Pln-RE gas analyzr _AVL_ smok mr _ Hydraulc dynamomr 6_hrmocoupl yp(k) 7_hrmocoupl yp(k) 8_hrmocoupl yp(k) 9_hrmocoupl yp(k) _ubochargr urbn _ubochargr comprssor _ Surg ank _ Manomr _Exhaus slncr _Prssur gag 6_Prssur gag 7_Prssur gag 8_Elcrcal spd mr 9_wasga _Ful mr _Ful gag _Ful nl _Rvrs ul Fgur : Block dagram o h s rg abl Spccaons o xprmnal ngn and urbochargr Engn and urbochargr Spccaon Engn yp srok dsl ngn Numbr o cylndr Combuson chambr Drc njcon Bor srok (mm) 97 8 Pson dsplacmn (cc) 78 Comprsson rao 7: Maxmum powr (hp) 8 Maxmum orqu (Nm) Maxmum spd (rpm) 8 Man cv prssur (bar) 68@8rpm urbochargr urbn Radal yp urbochargr comprssor Cnrugal yp s procdur h ss wr conducd wh varabl load a consan ngn spds o,,, 7 and rpm A ach oprang condon h dynamomr load, spd, ul low, ar low, soo dnsy, CO, CO, UHC and O wr rcordd ar sucn m or h ngn o sablz Also nl and oul mpraur and prssur o urbn and comprssor, ambn mpraur and prssur wr masurd Exhaus mssons calculaon In h ss, CO, CO, UHC and O wr masurd by Pln-RE gas analyzr Also soo was masurd by AVL- smok mr n ach s Ohr spcs n xhaus gas was calculad wh h ollowng chmcal quaon: mc H + z( O + 76N ν C + ν CO x + ν CO + ν N + ν H 8 y O ) + ν NO + ν O 6 + v C h molcular wgh o ul and s molcular ormula s consdrd as a havy dsl ul ( kg / kmol, C H n 7n ), hror h ormula o ul s C 9H 86 [] h unknown cocns ar ν, ν, ν, ν8, z, m Exhaus dnsy s calculad wh Eq() Ful and ar low also s masurd rspcvly wh Eq() and Eq() by orc,manomr and ul gag masurmn and characrscs hn soo low ra s calculad wh Eq() and Eq(6) h unknown cocns ar calculad wh us o quaons (7),(8),(9),(),() and () Equaon () s a xra chckng quaon 7 6 H () P ρ () ( 87 ( + 7)) In Eq(), s h urbn oul mpraur and P s urbn oul prssur h urbn oul prssur s assumd qual o ambn prssur ( P P ) m& c A 9 8 ρ h ρ () ar m& V d o m& a + m& ρ soo m& soo ρ V 6 l ρ orc ar () () (6)

3 ν m (7) soo z *76*9 mar m m z *76*9 m ar + v + v 6v7 (8) mx v + (9) my v + v () 7 8 z v + v () + v + v 6 *76z v + v () Pln-R masurs mssons n a mxur o CO, CO, N, NO, O, C 6 H and H O so: ν + ν + ν + ν + ν + ν + ν () Exrgy and rvrsbl work Exrgy s a hrmodynamc concp ha masurs h maxmum amoun o usul work ha can b xracd whn a sysm s brough no hrmodynamc qulbrum rvrsbly wh h nvronmn condons [9] In hs sudy, h ollowng assumpons wr mad: Egh xhaus's spcs wr consdrd (CO, CO, N, NO, O, H O, C and C 6 H ) n calculaon o xhaus xrgy All spcs comprsd carbon wr consdrd as dal gas Mol racon o spcs wr no changd hroughou h urbochargr h ul usd n h analyss was consdrd as C 9 H 86 Exhaus spcs wr assumd o b n chmcal qulbrum Snc w ar nrsd only n urbn, h procss occurrd n sady sa wh on nl and oul sady low condon h rs and scond law o hrmodynamcs can b wrn as, [6] m[ h h + + Q + W ( V V ) + g( z z )] Q Q k m ( s s) S gn ) k k k Qk () oal () Elmnang Q bwn h wo quaons ylds h ollowng xrgy balanc quaon W ( ) Qk + m( ψ ψ) S gn) oal (6) k k In Eq(6) ψ s h spcc low xrgy, can b calculad by Eq(7) ψ h h ( s s) + V + gz (7) Snc h oal nropy producon ra, S gn ) s oal srcly posv h powr bcoms maxmal or vanshng nropy producon or rvrsbl procss [ S gn ) ] hn h rvrsbl work qual: oal W rv ( ) Qk + m( ψ ψ ) (8) k k In urbochargr so: W rv h ( s k s )] o m ψ m( ψ ψ ) m[ h (9) For urbn wh nl condon (, P ) and oul condon (, P ) and h mol racon o componns n xhaus gas ar y, h rvrsbl work gvs maxmum urbn work oupu as: wrv) y ( ψ ψ ) y[ h h ( s s )] () Wrv) n wrv) Snc h mpraur drnc o comprssor and ambn s small, h comprssor s assumd adabac and changs n knc and ponal nrgs ar nglgbl Consqunly rs law o hrmodynamcs can b wrn as : m ar ( h h ) W c () In a urbochargr, h urbn s mchancally lnkd o h comprssor, so: W c η m () η m s urbn mchancal cncy h W In Eq(), mchancal losss ar manly barng rcon losss [7] In hs papr, h mchancal cncy s assumd qual o 97% Consqunly urbochargr can b wrn as, ηπ W η W rv) mar m n ( h n h ) y ( ψ ψ ) W c ( ) ηm y ( ψ ψ ) ()

4 Exprmnal rsuls and dscusson In ordr o nvsga h nlunc o ngn paramrs on o urbn n urbochargd dsl ngn, h ollowng ngn paramrs prsnd agans h urbochargr scond law cncy Ec o bmp on urbochargr scond law cncy Fgur shows h nlunc o bmp on urbochargr a drn consan spds As llusrad n h gur, urbochargr scond law cncy s ncrasd wh h ncras o bmp rpm rpm rpm 7rpm rpm 9 6 bmp(kpa) Fgur : Ecs o bmp on I s obvous ha as ngn spd s ncrasd, slop o h agans bmp s promod Also wh ncras o bmp n consan spd, work o urbn and xhaus xrgy drop n urbn s ncrasd, bu prcnag o ncras o work s hghr han prcnag o ncras o xhaus xrgy drop as shown n gur or spd o rpm Also or ohr spds prcnag o ncras o work s hghr han prcnag o ncras o xhaus xrgy drop as shown n gurs,,6 hs causs ha h urbochargr scond law cncy s ncrasd Nrpm prcnag(%) urbn powr oupu xhaus xrgy drop Nrpm bmp(kpa) Fgur : Prcnag o ncras o urbn powr oupu and xhaus xrgy drop agans bmp prcnag(%) urbn powr oupu xhaus xrgy drop N7rpm bmp(kpa) Fgur : Prcnag o ncras o urbn powr oupu and xhaus xrgy drop agans bmp prcnag(%) Nrpm urbn powr oupu 7 xhaus xrgy 6 drop 6 bmp(kpa) prcnag(%) urbn powr oupu xhaus xrgy drop bmp(kpa) Fgur : Prcnag o ncras o urbn powr oupu and xhaus xrgy drop agans bmp Fgur 6: Prcnag o ncras o urbn powr oupu and xhaus xrgy drop agans bmp Ec o quvalnc rao(ø) on urbochargr Fgur 7 shows h nlunc o quvalnc rao on urbochargr I s clar rom hs gur, as ø s ncrasd h urbochargr scond law cncy s ncrasd As ø s ncrasd h nl urbn mpraur s ncrasd as shown n gur 8, consqunly scond law cncy o urbn s ncrasd as H Sruchrup al, showd [8]

5 9 rpm rpm rpm 7rpm rpm Φ Fgur 7: Ecs o ø on Inl urbn mpraur( C) rpm rpm rpm 7rpm rpm Φ Fgur 8: Inl urbn mpraur agans quvalnc rao Ec o nl urbn mpraur on urbochargr As llusrad n gur 9 hghr nl urbn mpraur causs h hghr rpm rpm rpm 7rpm rpm 9 Inl urbn mpraur ( C) Fgur 9: Ecs o nl urbn mpraur on scond law cncy As orqu s ncrasd, h nl urbn mpraur s ncrasd bcaus wh ncras o h orqu, h charg o ngn s promod and hs causs h hghr work wh consan comprsson rao and h hghr mpraur and prssur n cylndrs consqunly h mpraur o xhaus gas s ncrasd Also n hghr spds h slop o cncy agans nl urbn mpraur s grar o H Sruchrup al, showd wh ncrasng n (rducon o nl urbn mpraur), scond law cncy o urbochargr s dcrasd hs s smlar o our rsuls [8] (gur ) 9 rpm rpm rpm 7rpm rpm o/n o Fgur : Ecs o on [8] n Wh addonal nl urbn mpraur, h work o urbn s ncrasd as nhalpy drop n urbn s ncrasd Bu wh anon o Eq(), nropy drop maks h ncras o work o urbn grar han h ncras o xrgy drop hs causs ncrasng h urbochargr (gurs,,, ) 8 6 o S rpm 6 Inl urbn mprur( C) Fgur : Varaon o and o S wh nl urbn mpraur (kw) 8 6 urbn powr oupu xhaus xrgy drop rpm 6 Inl urbn mpraur( C) Fgur : Varaon o urbn powr oupu and xhaus xrgy drop wh nl urbn mpraur

6 o S From rpm ll rpm ncrasng urbochargr (gurs 6, 7, 8, 9) (kw) 8 o S rpm - - Inl urbn mpraur( C) Fgur : Varaon o and o S wh nl urbn mpraur Inl urbn prssur(mpa) urbn powr oupu xhaus xrgy drop From rpm ll rpm Fgur 6: Varaon o and o S wh nl urbn prssur xhaus xrgy drop rpm 8 urbn powr oupu (kw) 6 Inl urbn mpraur( C) Fgur : Varaon o urbn powr oupu and xhaus xrgy drop wh nl urbn mpraur Ec o urbn nl prssur on urbochargr Fgur shows h nlunc o nl urbn prssur on urbochargr As shown n gur, wh ncras o nl urbn prssur h urbochargr s ncrasd I s also obvous ha h nl prssur urbn s graly acd by h ngn spd, as ngn spd s ncrasd; h urbochargr s also ncrasd 9 rpm rpm rpm 7rpm rpm 6 Inl urbn prssur(mpa) Inl urbn prssur(mpa) Fgur 7: Varaon o urbn powr oupu and xhaus xrgy drop wh nl urbn prssur - - o S Inl urbn prssur(mpa) Fgur 8: Varaon o and o S wh nl urbn prssur From rpm ll rpm xhaus xrgy drop urbn powr oupu From rpm ll rpm Fgur : Ecs o nl urbn prssur on scond law cncy Wh ncras o nl urbn prssur, h work o urbn s ncrasd as nhalpy drop n urbn s ncrasd Bu nropy drop maks ncras o urbn grar han h ncras o xrgy drop hs causs Inl urbn prssur(mpa) Fgur 9: Varaon o urbn powr oupu and xhaus xrgy drop wh nl urbn prssur 6

7 Concluson An xprmnal sudy o nvsga h c o ngn paramrs on o urbochargr was carrd h ollowng rsuls wr achvd: - Inl urbn mpraur: As llusrad n hs papr, wh ncras o bmp, xhaus gas mpraur or n ohr words nl urbn mpraur s ncrasd hs causs ha h urbochargr s ncrasd - Spd o ngn: As spd o ngn s ncrasd, h nl urbn mpraur s ncrasd consqunly h urbochargr s ncrasd - Exhaus prssur: As dscrbd n hs papr wh ncras o nl urbn prssur, h urbochargr s ncrasd - Ec o urbochargr on ransn opraon n urbochargd dsl ngns: Wh addonal urbochargr, h urbochargr d back n ransn runnng condons could b mprovd hs s bcaus o br avalabl work ransr bwn ngn cylndr and urbochargr So by hghr ngn spd, hghr nl urbn mpraur and prssur and hghr ul-ar rao, h ransn opraon o urbochargd dsl ngn may b mprovd Ls o Symbols A o orc ara (m ) Bmp brak man cv prssur(kpa) C d dscharg cocn o orc DI drc njcon g gravaonal acclraon (m/s ) h nhalpy (kj/kmol) m n P Q mass low ra (kg/s) mol low ra (kmol/s) prssur (kpa) ha ransr (kw) S ) oal nropy gnraon (kj/k) gn oal s nropy (kj/kmol K) mpraur(k) m or ul consumpon o cc (s) V vlocy (m/s) V w volum low ra(m /s) spcc work (kj/kmol) W powr (kw) y mol racon o spcs z hgh (m) monomr prssur drop h orc ψ spcc low xrgy (kj/kmol) η m mchancal cncy (%) η Π : (%) ρ dnsy (kg/m ) Subscrps c comprssor xhaus ul spcs k xrnal rsrvor l Lqud usd n manomr rv Rvrsbl o ambn urbn urbn nl urbn oul comprssor nl comprssor oul Rrncs [] Hywood, J, Inrnal combuson ngn undamnals Nw York: McGraw-Hll; 988 [] L, CS, Cho, NJ, "Ec o ar njcon on h characrscs o ransn rspons n a urbochargd dsl ngn", Journal o In J hrm Sc,,, 6-7 [] Galndo, J, Lujan, JM, Srrano, JR, Dolz, V, Gulan, S, "Dsgn o an xhaus manold o mprov ransn prormanc o a hgh-spd urbochargd dsl ngn", Journal o Exprmnal hrmal and lud Scnc 8 () [] Bnajs, J, Luj_an, JM, Brm_udz, V, Srrano, JR, "Modlng o urbochargd dsl ngns n ransn opraon Par : nsgh no h rlvan physcal phnomna", Procdngs o IMchE Par D: Journal o Auomobl Engnrng 6 (), D6 [] Gmml, H, Holz, HP, Wmann, HJ, "Compurzd smulaon o h acclraon characrscs o an xhaus gas urbochargd auomov dsl ngn", Procdngs o urbochargng and urbochargrs, papr C/8, I Mch E, London, England, (98), pp 7 8 [6] Bjan, A, Advancd Engnrng hrmodynamcs, Wly, Nw York, (988) [7] Son, R, Inroducon o nrnal combuson ngn, Hong Kong, 99 [8] Sruchrup, H, Rosn MA, "How much work s los n an rrvrsbl urbn, Journal o xrgy, an Inrnaonal Journal,, - 8 [9] Wark Jr, K, Advancd hrmodynamcs or ngnrngs, Sngapor: McGraw-Hll; (99) 7