Thermodynamic Analysis of a Turbocharged Diesel Engine Operating under Steady State Condition

Transcription

1 Journal of Alied Fluid Mechanics, Vol 9, No, , 016 Available online a wwwjafmonlinene, ISSN , EISSN Thermodynamic Analysis of a Turbocharged Diesel Engine Oeraing under Seady Sae Condiion B Menacer and M Boucheara Dearmen of Mechanical Engineering, Universiy of Sciences and he Technology of Oran, BP 1505 El - MNAOUER, USTO ORAN, Algeria Corresonding Auhor acermsn@homailfr (Received January 31, 015; acceed March 16, 015) ABSTRACT The urose of his work is o rovide a flexible hermodynamic model based on he filling and emying aroach for he erformance redicion of urbocharged comression igniion engine To validae he model, comarisons are made beween resuls of a develoed a comuer rogram in FORTRAN language and he commercial GT-Power sofware oeraing under differen condiions The comarisons show ha here is a good concurrence beween he develoed rogram and he commercial GT-Power sofware The variaion of he seed of he diesel engine chosen exends from 800 RPM o 100 RPM In his work, we sudied he influence of several engine arameers on he ower and efficiency Moreover, i us in evidence he exisence of wo oimal oins in he engine, one relaive o maximum ower and anoher o maximum efficiency I is found ha if he ecion ime is advanced, so he maximum levels of ressure and emeraure in he inder will be high Keywords: Thermodynamic; Combusion; GT-Power; Performance oimizaion; Forran; Filling and emying mehod NOMENCLATURE C1, C consans model of he remixed combusion C3D, C 4D consans of he diffusion combusion model C i krieger and borman consans C secific hea a consan ressure C v secific hea a consan volume c r comression raio D inder bore h for enhaly of formaion of he fuel k hoh consan of Hohenberg Q LHV lower heaing value of fuel comb Q rae of hea release during combusion Q oal hea release during he combusion Q h rae of he convecive hea ransfer Q in, Q ou inle and oule enhaly flows l connecing rod lengh ison sroke L m fb m fb burned fuel mass rae normalized burned fuel mass rae m f eced fuel mass er cycle m fb m fb d normalized fuel burning rae in he remixed combusion normalized fuel burning rae in he diffusion combusion m in mass flow hrough he inake valve m ou mass flow hrough he exhaus valve N N s engine seed inder number inder ressure max maximal cycle ressure average value of he ressure in he inder R gas consan T average value of he emeraure in he inder

2 norm normalized ime vary beween 0 and 1 comb, comb combusion duraion, ecion ime and angle, acual ime and angle ime measured wih resec o TDC U inernal energy V in-inder gas volume V clearance volume clear V dislacemen volume d W exernal work engine seed secific hea raio coefficien shae of he ison head ch coefficien shae of he inder head igniion delay id mb raio of conneced rod lengh o crank radius fuel-air equivalence raio 1 I NTRODUCTION More han one cenury afer his invenion by Dr Rudolf Diesel, he comression igniion engine remains he mos efficien inernal combusion engines for ground vehicle alicaions Thermodynamic models (zero-dimensional) and muli-dimensional models are he wo yes of models ha have been used in inernal combusion engine simulaion modeling Nowadays, rends in combusion engine simulaions are owards he develomen of comrehensive muli-dimensional models ha accuraely describe he erformance of engines a a very high level of deails However, hese models need a recise exerimenal inu and subsanial comuaional ower, which make he rocess significanly comlicaed and imeconsuming (Angulo-Brown e al 1994) On he oher hand, zero-dimensional models, which are mainly based on energy conservaion (firs law of hermodynamics) are used in his work due o heir simliciy and of being less ime-consuming in he rogram execuion, and heir relaively accurae resuls (Chen e al 00) There are many modeling aroaches o analysis and oimize of he inernal combusion engine Angulo-Brown e al (1994) oimized he ower of he Oo and Diesel engines wih fricion loss and finie duraion cycle Chen e al (00) derived he relaionshis of correlaion beween ne ower ouu and he efficiency for Diesel and Oo cycles; here are hermal losses only on he ransformaions in conac wih he sources and he hea sinks oher han isenroic Merabe e al (00) roosed a model for which he hermal loss is reresened more classically in he form of a hermal conducance beween he mean emeraure of gases, on each ransformaion V = consan, = consan, comared o he wall emeraure T wall Among he objecives of his work is o conduc a comaraive sudy of simulaion resuls of he erformances of a six inder direc ecion urbocharged comression igniion engine obained wih he elaborae calculaion code in FORTRAN and hose wih he sofware GT-Power We also sudied he influence of cerain imoran hermodynamic and geomeric engine arameers on he brake ower, on he effecive efficiency, and also on ressure and emeraure of he gases in he combusion chamber DIESEL ENGINE MODELING There are hree essenial ses in he mahemaical modelling of inernal combusion engine (Wason e al 1980): (1) hermodynamic models based on firs and second law analysis, hey are used since 1950 o hel engine design or urbocharger maching and o enhance engine rocesses undersanding; () Emirical models based on inu-ouu relaions inroduced in early 1970s for rimary conrol invesigaion; (3) Nonlinear models hysicallybased for boh engine simulaion and conrol design Engine modeling for conrol asks involves researchers from differen fields, mainly, conrol and hysics (Gogoi e al 010) As a consequence, several secific nominaions may designae he same class of model in accordance wih he framework To avoid any misundersanding, we classify models wihin hree caegories wih erminology adaed o each field : 1 hermodynamic-based models or knowledge models (so-called "whie box") for nonlinear model hysically-based suiable for conrol non-hermodynamic models or "black-box" models for exerimenal inu-ouu models 3 semihysical aroximae models or arameric models (so-called "grey-box") I is an inermediae caegory, here, model are buil wih equaions derived from hysical laws of which arameers (masses, volume, ineria, ec) are measured or esimaed using idenificaion echniques Nex secion focuses on caegory 1 wih greaer ineres on hermodynamic models For he second and hird class of models see Tschanz e al (01) 1 Thermodynamic-Based Engine Model Thermodynamic modeling echniques can be divided, in order of comlexiy, in he following grous (Heywood 1988): (a) quasi-sable (b) filling and emying and (c) he mehod of characerisics (gas dynamic models) Models ha can be adaed o mee one or more requiremens 574

3 for he develomen of conrol sysems are: quasiseady, filling and emying, inder-o-inder (CCEM) and mean value models (MVEM ) Basic classificaion of hermodynamic models and he emergence of aroriae models for conrol are shown in Fig1 Quasy- S d MVEM Siml Thermodynamic models CCEM Filling and i Model Srucure Fig 1 Basic classificaion of hermodynamic models of inernal combusion engines 11 Quasi-Seady Mehod Gas dynamics Real ime Simulaion High Comuing The quasi-seady model includes crankshaf and he urbocharger dynamics and emirical relaions reresening he engine hermodynamic (Frank e al 013 and Benson e al 1973) Quasi-seady models are simle and have he advanage of shor run imes For his reason, hey are suiable for realime simulaion Among he disadvanages of his model was he srong deendence of he exerimenal daa and he low accuracy Thus, he quasi-seady mehod is used in he combusion subsysem wih mean value engine models o reduce comuing ime 1 Filling and Emying Mehod Comle Under he filling and emying conce, he engine is reaed as a series of inerconneced conrol volumes (oen hermodynamic volume) (Krishna e al 010 and Wason e al 1981) Energy and mass conservaion equaions are alied o every oen sysem wih he assumion of uniform sae of gas The main moivaion for filling and emying echnique is o give general engine models wih he minimum requiremen of emirical daa (mas of urbine and comressor sulied by he manufacurer) In his way, he model can be adaed o oher yes of engines wih minimal effor Filling and emying model shows good redicion of engine erformance under seady sae and ransien condiions and rovides informaion abou arameers known o affec olluan or noise However, assumions of uniform sae of gas cover u comlex acousic henomena (resonance) 13 Mehod of Characerisics (or Gas Dynamic Models) I is a very owerful mehod o access accuraely arameers such as he equivalence raio or he conribuion o he overall noise sound level of he inake and he exhaus manifold Is advanage is effecively undersood he mechanism of he henomena ha haen in a manifold (Galindo e al 010) and, allows o obain accuraely laws of evoluion of ressure, seed and emeraure manifolds a any oin, deending on he ime, bu he characerisic mehod requires a much more imoran calculaion rogram, and he rogram's comlexiy increases widely wih he number of singulariies o be reaed 3 GENERAL EQUATION OF THE MODEL In his work we develoed a zero-dimensional model roosed by Wason e al (1981), which gives a saisfacory combusion hea o calculae he hermodynamic cycle In his model, i is assumed ha: engine lenums (inders, inake and exhaus manifolds) are modelled as searae hermodynamic sysems conaining gases a uniform sae The ressure, emeraure and comosiion of he inder charge are uniform a each ime se, which is o say ha no disincion is made beween burned and unburned gas during he combusion hase inside he inder Wih resec o he filling and emying mehod, mass, emeraure and ressure of gas are calculaed using firs law and mass conservaion Ideal gases wih consan secific heas, effecs of hea ransfer hrough inake and exhaus manifolds are negleced; comressor inle and urbocharger oule emeraures and ressures are assumed o be equal o ambien ressure and emeraure From he resuls of Rakaoulos e al (004); emeraures of he inder head, inder walls, and ison crown are assigned consan values The crank seed is uniform (he urbocharged comression igniion engine is oeraing a seady sae) The rae of change of he volume wih resec o ime is given as follows, Fig: Inle h D X L mf P, T, m, V Fig Cylinder scheme and is variables, (P: ressure, T: emeraure, m: mass, V: volume) θ Oule T 575

4 D L V Vclear 1 mb 1 cos 4 1 sin mb (1) 31 Fuel Burning Rae There are wo emirical models o deermine he fuel burning rae: he simle Vibe law and he modified or double Vibe funcion following he Wason and al model In his simulaion, we chose he single zone combusion model roosed by Wason and al (1980) This correlaion develoed from exerimenal ess carried ou on engines wih differen characerisics in differen oeraing regimes This model reroduces in wo combusion hases; he firs is he faser combusion rocess, said he remixed combusion and he second is he diffusion combusion which is slower and reresens he main combusion hase During combusion, he amoun of hea release Q comb is assumed roorional o he burned fuel mass: dq dm comb fb h for () dm dm * fb fb m f comb (3) The combusion rocess is described using an emirical model, he single zone model obained by Wason and al (1980): dm dm dm fb fb fb 1 d (4) : Fracion of he fuel eced ino he inder and ariciaed in he remixed combusion hase I deends on he igniion delay id described by Arrhenius formula (Abbe, H 013) and he equivalence raio 1 / 3 1 id (5) 1,, 3: Emirical consans for fuel fracion in he remixed combusion ( 1 090, 035, ) The equivalence raio is defined as: m fb ( )/ m s (6) a m a : Mass air ariciaing in fuel combusion [kg] S : Soichiomeric fuel-air raio In diesel engine, in which qualiy governing of mixure is used, he equivalence raio varies grealy deending on he load The fuel burned mass m s m fb 1 s m fb is wrien as follows: (7) From he equaions (6) and (7), one obains he sae equaion of he equivalence raio (Bakhshan, Y e al 013): d 11 dm fb dm s s m s (8) The igniion delay in [ms] is he eriod id beween ecion ime and igniion ime and i calculaed by Arrhenius formula: id k 3 k T k 1 e (9) k1 0,0405; k 0,757; k : These coefficiens are exerimenally deermined on raid comression engines and valid for he ceane number beween 45 and 50, (Sakhrieha, 010) 311 Fuel Burning Rae during he Premixed Combusion The normalized fuel burning rae in he remixed combusion is (Heywood 1988 and Wason e al 1981): dm fb C 1 1 C 1 ( C 1) C 1 C (1 ) norm norm norm ( )/ comb comb C C id N (10) (11) 31 Fuel Burning Rae during he Diffusion Combusion The fuel burning rae in he diffusion combusion is calculaed as (Wason e al 1981): C C C 4 dm fb 4 1 ( d d 3d norm ) C 3d C 4d norm e d C 14 / d o C d C 3d (1) 576

5 3 Hea Transfer in he Cylinder Hea ransfer affecs engine erformance and efficiency The hea ransfer model akes ino accoun he forced convecion beween he gases raed ino he inder and he inder wall The hea ransfer by conducion and radiaion in he engine block are much less imoran han he hea ransfer by convecion (Shahrir e al 008) The insananeous convecive hea ransfer rae from he in-inder gas o inder wall Q h is calculaed by: dq h A h ( T T wall ) (13) Twall : Temeraure walls of he combusion chamber (bounded by he inder head, ison head and he inder liner) From he resuls of Rakaoulos e al (004),Twall is assumed consan The insananeous hea exchange area A can be exressed roughly by he following relaion: D S A ch D 4 (14) l l 1 cos sin r r For fla area ch, and for no fla area, ch The global hea ransfer coefficien in he inder can be esimaed by he emirical correlaion of Hohenberg which is a simlificaion of he Woschni correlaion; i resens he advanage o be simler of use and is he mos adequae among all available relaions o comue he hea ransfer rae hrough inder walls for diesel engine (Hohenberg, GF 1979) The hea ransfer coefficien h in [kw/k m ] a a given ison osiion, according o Hohenberg s correlaion (Hohenberg, GF 1979) is: h () k ( 14) 08 hoh V T vis (15) khoh 130, he consan of Hohenberg which characerize he engine The mean ison seed v _ is [m/s], is equal o: V is SN 33 Energy Balance Equaions (16) In he filling and eming mehod, only he law of conservaion energy is considered The energy balance of he engine for a conrol volume consiued by he inder gasses is esablished over a comlee cycle: du dw dq (17) The inernal energy U er uni mass of gas is calculaed from a olynomial inerolaion deduced from he calculaion resuls of he combusion roducs a equilibrium for a reacion beween air and fuel CH n n The olynomial inerolaion is a coninuous funcion of emeraure and equivalence raio I is valid for a emeraure range T beween 50 K and 400 K and equivalence raio beween 0 and 16 To deermine he change in inernal energy, we use he exressions of Krieger and Borman (1966): du da db / 1 dt dt dt s (18) da C C 1 T C T C 3 T C 4 T dt (19) db C C T C T C T 3 (1) dt da db, : Inerolaion olynomial of Krieger and dt dt Borman The work rae is calculaed from he inder ressure and he change in inder volume: dv dw (0) The oal hea release Q during he combusion is divided in four main erms: dq dq dq dq dq in comb ou h (1) wih; dq in C m in T a dq ou C m ou T dq comb m fb Q LHV () The rae of change of mass inside he inder is evaluaed from mass conservaion, and is as follows: dm m f m in m ou (3) From he energy balance, we can deduce he emeraure of gases in he inder T (Heywood 1988): 577

6 dt dq [( h dm dm h 0 h 0 in ou dq dm comb 1 u ) m RT dv ud u ]/ V T (4) In Eq 4, many erms will be zero in some conrol volumes all or some of he ime For examles: dv : Zero for he manifolds, h0 dm and h 0 dm : Zero for he inder, in ou dm fb : Zero he manifolds, dm u : Zero for he inder exce for mass addiion of fuel during combusion, dq h : Negleced for he inle manifolds, u : Zero for he inder exce during combusion (when fuel is added, hence changes), Secific enhalies h 0 and h in 0 (exce he ou secific enhaly of formaion h for ) are consan values By alicaion of he firs Law of hermodynamics for he inder gas, Eq 4 became: dt 1 dq dv m C v The sae equaion of ideal gas is given by: (5) V m RT (6) Rearranging Eq 1, 4, 5, 6; he sae equaion for inder ressure finally becomes: d RT m RT m V V in in ou 1 m Q Q V bf LHV h (7) Wih; C / C v For he urbocharger dynamics, he roaional seed of he urbocharger assembly c can be derived from Newon s law: d c P P c (8) Jcc Where J c is he urbocharger momen of ineria, P and P c are he urbine and comressor ower Here, he urbocharged is oeraing under seady sae ( c 0 ), and he bearing fricions are negleced To evaluae he differenial equaion (4) or (7), all erms of he righ side mus be found The mos adaed numerical soluion mehod for hese equaions is he Runge-Kua mehod 34 Fricion Losses Fricion losses no only affec he erformance, bu also increase he size of he cooling sysem, and hey ofen reresen a good crierion of engine design The model roosed by Chen and Flynn (1965) demonsrae ha he value of he mean fricion ressure fme [bar], be comosed of a mean value C and addiive erms correlaed wih he maximal cycle ressure max and he mean ison seed v _ is The mean value C, suosed consan, deends on he engine ye and reresens a consan base ressure which is o be overcome _ firs The erm deending on v is, reflec he fricion losses in he inder (ison-shir) The maximal cycle ressure characerizes max he losses in he mechanism ison-rod-crankshaf So he fricion mean effecive ressure is calculaed by (Heywood 1988): fme C 0005 max 016 v is (9) For direc ecion diesel engine C 0130 bar 35 Effecive Power and Effecive Efficiency For he 4-sroke engine, he effecive ower is (Heywood 1988): bower bmev d N s N / (30) Wih; V d D S/4 The effecive efficiency is given by (Heywood 1988): R eff Wd / Q comb (31) 4 ENGINE SIMULATION PROGRAMS 41 Comuing Ses of he Develoed Simulaion Program The calculaion of he hermodynamic cycle according o he basic equaions menioned above requires an algorihm for solving he differenial equaions for a large number of equaions describing he iniial and boundary condiions, he kinemaics of he crank mechanism, he engine 578

7 geomery, he fuel and kineic daa I is herefore wise o choose a modular form of he comuer rogram The develoed ower cycle simulaion rogram includes a main rogram as an organizaional rouine, bu ha incororaes a few echnical calculaions, and also several subrouines The comuer rogram calculaes in discree crank angle incremenal ses from he sar of he comression, combusion and exansion sroke The rogram configuraion allows hrough subrouines o imrove he clariy of he rogram and is flexibiliy The basis of any ower cycle simulaion is above all he knowledge of he combusion rocess This can be described using he modified Wiebe funcion including arameers such as he combusion ime and he fracion of he fuel eced ino he inder For he closed cycle eriod, Wason recommended he following engine calculaion crank angle ses: 10 ºCA before igniion, 1º CA a fuel ecion iming, º CA beween igniion and combusion end, and finally 10 º CA for exansion The comuer simulaion rogram includes he following ars: Inu engine, urbocharger and inercooler daa Engine geomery ( D, S, l, r ), Engine consan ( N,, C ), Turbocharger consan ( c,, amb, r Tamb, m, ICE,, T,, T ou, ur ou, ur ou, man ou, man ) and olynomial coefficien of hermodynamic roeries of secies Calculaion of inercooler and urbocharger hermodynamic arameers Comressor oule ressure, comressor oule c emerauret, comressor oule masse flow c rae m, inercooler oule ressure, inercooler c ic oule emeraure T ic, inercooler oule masse flow rae m, urbine oule ressure, urbine oule ic emerauret, urbine oule masse flow rae m consan volume C v ) o Calculaion of he combusion hea, he hea hrough walls and he gas inside and ouside he oen sysem o Calculaion of main engine erformance arameers menioned above Ouu of Daa block Insananeous inder ressure, insananeous inder emerauret, indicaed mean effecive ressure ime, fricion mean effecive ressure fme, mean effecive ressurebme, indicaed ower iower, fricion ower fower, brake owerbower The comuer simulaion ses of a urbocharged diesel engine are given by he flowchar in Fig3 4 Commercial Engine Simulaion Code The GT-Power is a owerful ool for he simulaion of inernal combusion engines for vehicles, and sysems of energy roducion Among is advanages is he faciliy of use and modeling GT- Power is designed for seady sae and ransien simulaion and analysis of he ower conrol of he engine The diesel engine combusion can be modeled using wo funcions Wiebe (Gamma, Technologies 009) GT-Power is an objec-based code, including emlae library for engine comonens (ies, inders, crankshaf, comressors, valves, ec) Figure 4 shows he model of a urbocharged diesel engine wih 6 inders and inercooler made wih GT-Power In he modeling echnique, he engine, urbocharger, inercooler, fuel ecion sysem, inake and exhaus sysem are considered as comonens inerconneced in series 41 Injecion Sysem The simle ecion sysem is used o ec fluid ino inder and used for direc-ecion diesel engines Table1 shows he arameers of he ecion sysem Calculaion of engine erformance arameers o Calculaion of he iniial hermodynamic daa (calorific value of he mixure, sae variables o close he inle valve, comression raioc r ) o Calculaion of he ison kinemaic and hea ransfer areas o Main rogram for calculaing he hermodynamic cycle arameers of comression, combusion and exansion sroke o Numerical soluion of he differenial equaion (he firs law of hermodynamics) wih he Runge-Kua mehod o Calculaion of he secific hea (secific hea consan ressure C and secific hea a Tabel 1 Injecion sysem arameers (Gamma, Technologies 009) Injecors arameers unis Values : Injecion ressure [bar] 1000 T : Sar of ecion btdc [ CA] 15 BTDC n : Number of holes er nozzle [-] 8 d : Nozzle hole diameer [mm] 05 4 Inle Manifold and Exhaus Manifold In he inake manifold, he hermal ransfers are negligible in he gas-wall inerface This hyohesis 579

8 Begin Inu engine, urbocharger and inercooler daa: Engine geomery ( D, S, l, r), Engine consan ( N, Cr, ), Turbocharger consan ( c,, amb, Tamb, m, ICE, ou, ur ) and olynomial coefficien of hermodynamic roeries of Comue: Parameers of Comressor (, T, m c ) and Turbine (, T, m) and inercooler (, T, m ic ) c ic c ic Engine cycle Calculaion Comue: Consan daa of inder filling, fuel lower heaing, mean ison seed Comue: Insananeous inder volume, insananeous hea exchange area Main rogram and conrol uni o comue: Iner- Cylinder arameers: T,, V, min; Comression, Combusion and Exansion sroke Subrouine o solving he differenial equaion wih he Runge-Kua mehod and increase crank angle Comue: Secific heas Comue: Combusion arameers: dm fb, dq comb dm fb, dm fb d o and inder hea ransfer dq h, Comue: Engine erformances arameers: ime, fme, bme, iower, fower, bower, Rind, Reff, Rmec, Torque Plo and /or save all resuls End Fig 3 Schemaic Flowchar of he develoed comuer simulaion rogram 580

9 Inake manifold Injecors Cylinder Valves Crank shaf Hea exchanger Exhaus manifold Turbocharger Fig 4 Develoed model in he commercial engine simulaion code GT-Power 581

10 is acceable since he collecor's emeraure is near o he one of gases ha i conains The variaion of he mass in he inake manifold deends on he comressor mass flow and he flow hrough of valves when hey are oen In he modeling view, he line of exhaus manifold of he engine is comosed in hree volumes The inders are groued by hree and emerge on wo indeenden manifold, comonen wo hermodynamic sysems oened of idenical volumes A hird volume smaller assures he juncion wih he wheel of he urbine 43 Turbocharger Turbocharging he inernal combusion engine is an efficien way o increase he ower and orque ouu The urbocharger consiss of an axial comressor linked wih a urbine by a shaf The comressor is owered by he urbine which is driven by exhaus gas In his way, energy of he exhaus gas is used o increase he ressure in he inake manifold via he urbocharger As a resul more air can be added ino he inders allowing increasing he amoun of fuel o be burned comared o a naurally asiraed engine 44 Hea Exchanger or Inercooler The hea exchanger can be assimilaed o an inermediae volume beween he comressor and he inake manifold I comes o solve a sysem of differenial equaions sulemenary idenical o he manifold I aeared o assimilae he hea exchanger as a non-dimensional organ (one suoses ha i doesn' accumulae any gas) wih increase of he effecive ower unil is maximum value, afer i begins o decrease unil a maximal value of he effecive ower I is also valid for he effecive ower If he comression raio increases from 16:1 o 19:1, he maximal efficiency increases of % and he maximal ower of 15% and he hea flux of 10% for GT-Power and he elaborae sofware Table Engine secificaions Engine arameers Values Bore, D [mm] 100 Sroke, S [mm] 1750 Dislacemen volume, V d [cm 3 ] 1978 Connecing rod lengh, l [ mm] 3000 Comression raio, [-] 160 Inle valve diameer, [mm] 60 Exhaus valve diameer, [mm] 38 Inle Valve Oen IVO, [ CA] 314 Inle Valve Close IVC, [ CA] -118 Exhaus Valve Oen EVO, [ CA] 100 Exhaus Valve Close EVC, [ CA] 400 Injecion iming, [ CA] 15 BTDC Fuel sysem, [-] Direc ecion Firing order, [-] RESULTS OF ENGINE SIMULATION Thermodynamic and geomeric arameers chosen in his sudy are: Engine geomery: comression raio C, r inder bore D and more aricularly o he L sroke bore raio R sb D Combusion arameers: eced fuel mass m, crankshaf angle T f marking he ecion iming and inder wall emerauret wall The able show he main arameers of he chosen direc-ecion diesel engine 51 Influence of he Geomeric Parameers Fig 5(a) Comression raio influence a 100% load, T = 15 btdc, D =10 mm, T wall = 450 K, R sb = Comression Raio In general, increasing he comression raio imroved he erformance of he engine Figures 5(a) and 5(b) shows he influence of he comression raio (Cr= 16:1 and 19:1) on he brake ower versus effecive efficiency and he hea flux a full load, advance for GT-Power and he elaborae sofware The brake efficiency increases Fig 5(b) Comression raio influence on hea flux a 100% load, T = 15 btdc, D =10 mm, T wall = 450 K, R sb =15 58

11 51 Sroke-Bore Raio The sroke bore raio is anoher geomeric arameer ha influences on he erformances of a urbocharged diesel engine The Cylinder volume of 0 l can be obained by a differen manner while varying his arameer; is influence is shown in Fig 6(a) If he sroke bore raio increase, he mean ison seed is greaer, and fricion losses (Eq10) are imoran wih increasing he engine seed (view Fig 6(b)) The effecive ower and he brake efficiency decrease wih he increase of he sroke bore raio If he sroke bore raio augmens of 05 (of 15 o ) hen, he maximum brake efficiency decreased an average of 3%, and he maximum effecive ower of 4% difference emeraure beween gas and wall inder is less, hen he losses by convecive exchange is high (Gamma, Technologies 009) If he inder wall emeraure increase by 100 K (from 350 K o 450 K), he maximum of brake ower and effecive efficiency decrease resecively by abou 07% The maximum oeraing emeraure of an engine is limied by he srengh and geomeric variaions due o hermal exansion, which can be a danger of galling Imroved hea ransfer o he walls of he combusion chamber lowers he emeraure and ressure of he gas inside he inder, which reduces he work, ransferred o he ison inder and reduces he hermal efficiency of he engine I is hus advanageous o cool he inder walls rovided and hey do no do i oo vigorously Fig 6(a) Influence of Sroke bore raio for 100% load, T = 15 btdc, v =0 l, C = 16:1 r Fig 7(a) Wall emeraure influence for 100% load, T = 15 btdc, D =10 mm, C = 16:1 r Fig 6(b) Influence of Sroke bore raio on hea flux for 100% load, T = 15 btdc, v =0 l, C = 16:1 r 5 Influence of he Thermodynamic Parameers 51 Cylinder wall Temeraure The influence of he inder wall emeraure is reresened also in Fig 7(a) and Fig 7(b), when he inder wall emeraure is lower, hen he brake efficiency increase From he Fig 7(b) more he Fig 7(b) Wall emeraure influence on hea flus for 100% load, T = 15 btdc, D =10 mm, C r = 16:1 5 Advanced Injecion Figures 8(a) and 8(b) shows he influence of differen ecion iming on he variaion of he hea flux and he maximum brake ower versus he maximum effecive efficiency for he boh sofware; Forran and GT-Power This arameer has a 583

12 subsanial influence on he brake ower and less on effecive efficiency If he advance ecion is advanced (from 5 atdc o 15 btdc) hen he hea flux from fluid o he combusion chamber wall is high Fig 9(a) Mass fuel eced influence for T = 15 btdc, D =10 mm, C r = 16:1, T wall = 480 K Fig 8(a) Injecion iming influence for 100% load, D =10 mm, C r = 16:1, T wall = 450 K 5 Fig 8(b) Injecion iming influence on hea flux for 100% load, D =10 mm, C r = 16:1, T wall = 450 K 53 Masse Fuel Injeced Figures 9(a) and 9(b) shows he variaion of he brake ower versus effecive efficiency and he hea flux for differen masse fuel eced a advance ecion of 15 btdc, comression raio of 16:1, and N = 1400 RPM This arameer has a srong influence on he brake ower, hea flux and i has a less influence on he effecive efficiency The brake ower and effecive efficiency increases wih increasing he quaniy of fuel eced If he masse fuel eced in he inder increase by 50% (from 50% o 100%), so he effecive efficiency increase of 35%, he brake ower of 85% and he hea flux of 15% I shows he imorance of he variaion of he quaniy of eced fuel on he effecive ower and he brake efficiency Fig 9(b) Mass fuel eced influence on hea flux for T = 15 btdc, D =10 mm, C = r 16:1, T wall = 480 K 5 6 CONCLUSION This work describes a urbocharged direc ecion comression igniion engine simulaor Effor has been u ino building a hysical model based on he filling and emying mehod The resuling model can redic he engine erformances From he hermodynamic model we are able o develo an inerrelaionshi beween he brake ower and he effecive efficiency ha is relaed o he corresonding seed for differen arameers sudied; i resuls an exisence of a maximum ower corresonding o a sae for an engine oimal seed and a maximum economy and corresonding oimal seed We sudied he influence of cerain number of arameers on engine ower and efficiency: The following arameers as; srokebore raio and he inder wall emeraure, have a small influence on he brake ower and effecive efficiency While he angle of sar ecion, mass fuel eced, comression raio have grea influence on he brake ower and effecive efficiency This analysis has been comleed by reresenaion of he ressure diagram for various he crankshaf angle, and he corresonding gas emeraure versus crankshaf angle The engine simulaion model described in his work is valid for seady engine seed In fuure work we aim o relace he simle 584

13 model for fracion of mass fuel burned by a redicive model, o validae his model for ransien engine seed and o ake in accoun gas characerisics and secific hea flucuaion ACKNOWLEDGMENTS This research has been accomlished enirely wih he resources and ime of he auhor I received no secific gran from any funding agency in he ublic, commercial, or no-for-rofi secors REFERENCES Abbe, H, S Roengruber, M Seifer and J Ringler (013) Dynamic hea exchanger model for erformance redicion and conrol sysem design of auomoive wase hea recovery sysems Alied Energy 105, Angulo-Brown, F, J Fernandez-Beanzos and C A Diaz-Pico (1994) Comression raio of an oimized Oo-cycle model Euroean journal of hysics 15, 38-4 Bakhshan, Y and A H Shadaei (013) Quasi- Dimensional Modeling of a CNG Fueled HCCI Engine Combusion Using Deailed Chemical Kineic Journal of Alied Fluid Mechanics 6(), Benson, R S and P C Baruah (1973) Some furher ess on a comuer rogram o simulae inernal combusion engine SAE Technical Paer Chen, L, J Lin, J Lou and C Wu (00) Fricion effec on he characerisic erformances of Diesel engines Inernaional Journal of Energy Research 6, Chen, S and P Flynn (1965) Develomen of a single inder comression igniion reseach engine SAE Transacion Frank, W, K Frank, R George and F Emanuel (013) Inegraed Energy and Emission Managemen for Diesel Engines wih Wase Hea Recovery Using Dynamic Models Oil & Gas Science and Technology Rev IFP Energies nouvelles Galindo, J, F J Arnau, A Tiseira and P Piqueras (010) Soluion of he Turbocomressor boundary condiion for one-dimensional gasdynamic codes Mahemaical and Comuer Modelling 5, Gamma, Technologies GT-Power User smanual, GT-Suie Version 70; GT-Power roduc flyer, he Indusry Sandard, (009) Gogoi, T K and D C Baruah (010) A cycle simulaion model for redicing he erformance of a diesel engine fuelled by diesel and biodiesel blends Energy 35(3), Heywood, J B(1988) Inernal Combusion Engine Fundamenals McGraw-Hill, New york, USA Hohenberg, G F (1979) Advanced aroaches for hea ransfer calculaions SAE Technical Krieger, R and G Borman (1966) The comuaion of aaren hea release for inernal combusion engines Proceedings of Diesel Gas Power, ASME, 66-WA/DGP-4 Krishna, B M and J M Mallikarjuna (010) Characerizaion of Flow hrough he Inake Valve of a Single Cylinder Engine Using Paricle Image Velocimery Journal of Alied Fluid Mechanics 3(), 3-3 Merabe, A, M Fei and A Bouchoucha (00) Effe du ransfer de chaleur sur les erformances d un moeur à ` combusion inerne amoshérique foncionnan suivan un cycle mixe Termoehnica, Rakooulos, C D, C D Rakooulos, G C Mavrooulos and E GGiakoumis (004) Exerimenal and heoreical sudy of he shor-erm resonse emeraure ransiens in he inder walls of a diesel engine a various oeraing condiions Alied Thermal Engineering 4, Sakhrieha, A and E Abu-Nada (010) Comuaional Thermodynamic Analysis of Comression Igniion Engine Inernaional Communicaions in Hea and Mass Transfer 37, Shahrir, A, H K Wendy and S Azhari (008) Numerical Analysis of he Combusion Process in a Comressed Naural Gas Direc Injecion Engine Journal of Alied Fluid Mechanics 1(), Tschanz, F, A Amsuz, C Onder and L Guzzella (01) Conrol of diesel engines using NOxemission feedback Inernaional Journal of Engine Research 18, Wason, N (1981) Transien erformance simulaion and analysis of urbocharged diesel engines SAE Technical , Wason, N, A D Pilley and M Marzouk (1980) A combusion correlaion for diesel engine simulaion SAE Technical