© © a nut h aaee sdt esr h ffcieeso nengine’s an of effectiveness engine the the an measure is which to process air used induction of SIE), parameter amount a The the (in induct. restricts plate can – throttle valve and port, carburettor, manifold, filter, intake air – system intake Engine V N m m r d auu a (BUET) Haq Zahurul Md. Dr. (BUET) Haq Zahurul Md. Dr. ˙ • • d a a efrac fteoealiltsystem. inlet overall the of performance efrac fteclne,iltpr n av alone. valve and port inlet cylinder, the of performance If If η v niedslcmn volume displacement engine = cylinder cycle the into per rate cylinder induction the air into = inducted air of mass = niespeed, engine = ρ ρ a a ≡ , , i i = = ρ a m , ρ ne aiodardensity: air manifold inlet agaehUiest fEgneig&Tcnlg (BUET) Technology & Engineering of University Bangladesh i V a a , d o E47 nenlCmuto Engines Combustion Internal 417: ME ouercEcec fEngines of Efficiency Volumetric http://zahurul.buet.ac.bd/ME417/ amshrcardensity): air (atmospheric = ρ eateto ehnclEngineering Mechanical of Department a m , ˙ A i ouercefficiency, volumetric V a p d r d auu Haq Zahurul Md. Dr. http://zahurul.buet.ac.bd/ ouercEcec fEngines of Efficiency Volumetric Engines of Efficiency Volumetric itnarea, piston = hk-00 Bangladesh Dhaka-1000, X N [email protected] = ρ m Professor ˙ a a , i A 2 p X ⇒ S p S η p ouercEfficiency, Volumetric v ⇒ v itnspeed piston av. = X esrstepumping the measures η η = v v . esrstepumping the measures  o sengine 4s for engine 2 2s for 1 E47(01 21 / 3 (2021) 417 ME 21 / 1 (2021) 417 ME η v © © nnature in hnmn htacmaytetm-ayn aueo h a exchange gas the of nature time-varying processes.) the accompany that phenomena oeo h aibe r essentially are variables the of Some r d auu a (BUET) Haq Zahurul Md. Dr. (BUET) Haq Zahurul Md. Dr. 7 6 5 4 3 2 1 • • • • abrtdegnsado i n ae aorol nDee and Diesel in ‘ only Subscript in vapour fuel water engines. and fuel-injection and vapour, other air water of air, and of engines consist carbureted These valve. inlet the naeadehutvlegoer,sz,lf,adtimings and lift, size, geometry, valve exhaust design and port Intake and manifold exhaust and Intake speed Engine pressures ratio manifold Compression inlet to exhaust transfer of heat Ratio by influenced as intake temperature vaporization the Mixture of in heat vaporized fuel fuel and of system, fraction ratio, fuel/air type, Fuel Charge Gas Residual Mixture Fresh Process Induction itr,adsbcit‘ subscript and mixture, pnn (IVO, opening usrp ‘ Subscript hrecnit ftefehmxueadtersda gases. residual the and mixture fresh the of consists charge ie hi ffcsdpn nteused o n rsuewave pressure and flow unsteady the on depend effects their (i.e. h otnso h yidratrcoigo l avs the valves; all of closing after cylinder the of contents the : r sue nrfrigt hs gases. these to referring in used is ’ h ae eti h hrefo h rvoscycle. previous the from charge the in left gases the : θ e ae nutdit h nieclne through cylinder engine the into inducted gases new : vo n ne av lsn (IVC, closing valve inlet and ) vnsta aepaebteniltvalve inlet between place take that events : ouercEcec fEngines of Efficiency Volumetric Engines of Efficiency Volumetric a orfrt h i ntefehmixture. fresh the in air the to refer to ’ us tayi nature in steady quasi i sue orfrt h fresh the to refer to used is ’ Definitions/Terminology atr Affecting Factors θ vc ). E47(01 21 / 4 (2021) 417 ME 21 / 2 (2021) 417 ME or , dynamic η v T510 © © r 0 P n 00K sueta xas ytmpesr s15kPa, 105 is pressure system exhaust that Assume and K. 1.35, 1000 and kPa 500 are rai 2 is area = ⊲ ⇒ ⇒ ⇒ ⇒ r d auu a (BUET) Haq Zahurul Md. Dr. (BUET) Haq Zahurul Md. Dr. • • siaetemxmmflwrt hog nehutvle ftevlecurtain valve the if valve, exhaust an through rate flow maximum the Estimate needn fdwsra rsue hkdflwrate, flow Choked pressure. downstream of independent m c ρ pressure, static valve flow, choked For flow Choked P ˙ P o o down cr up = = . 7 = R P = √ × RT P P ρ down kRT 8 /gK. J/kg 287 = o 10 up 105 500 o o c = o − A o = 3 ≥ 287 m C 500 = 4 C 2  . × cusa av hotif throat valve a at occurs h valve the , √ D × 76 1000 m P 10 1 ˙ P down . cr > k 3 35 + up 2 1 1 = = × .
6 hkdflow. choked 86:  ( 1 ouercEcec fEngines of Efficiency Volumetric Engines of Efficiency Volumetric ρ k 287 . + cr o 74 C c 1 ) o = D / × kg A 2 s06adclne rsueadtemperature and pressure cylinder and 0.6 is (  C 1000 / k xas toe&Rsda Mass Residual & Stroke Exhaust − m C k 1 D 3 ) + 2 =  = 1 k 1 622  . • • • 02 + 2 k P / . f T P T ( 1 45 r kg k e e  − ≡ eed on depends / m ≡ 1 ≡ ( k s ) T eiulgsfraction gas residual / + ⊳ = xas a pressure gas exhaust e xas a temperature gas exhaust s f 1 r ) = / 1 = 2 . ( 86 T k 1 r − 4 E47(01 21 / 7 (2021) 417 ME 21 / 5 (2021) 417 ME 1   ) P P P if P P 4 e 4 e o m  ˙ k  and cr k 1 k = − k is 1 1 . 35 k = T511 © © r d auu a (BUET) Haq Zahurul Md. Dr. (BUET) Haq Zahurul Md. Dr. • • • • • • • L L lift. area, of seat function Valve strong a not is value area, curtain Valve assembly, valve of area Effective valve, exhaust an through cylinder the of out flow For valve: intake an through cylinder the into flow For speed sound and the restriction: by flow described a usually through is flow valve compressible for Poppet equation a through rate flow Mass fteflwrestriction flow the of pressure stagnation Upstream v v / svlelift, valve is D P P P P v T T o o m ˙ r 0.25. are h yidrpressure cylinder the = pressure, system intake the = h xas ytmpressure. system exhaust the = pressure. cylinder the = = ρ o c o D A A v ≡ E S svledaee.Tpclmxmmvle of values maximum Typical diameter. valve is A  c ( = o C P P ≡ ouercEcec fEngines of Efficiency Volumetric Engines of Efficiency Volumetric = T = o π/ P  av lw&DshreCoefficients Discharge & Flow Valve √ π 4 T 1 D kRT ) / . D k v v L " 2 ≡ , v o k , C P A n ttcpesr utdownstream just pressure static and ; − 2 C F o E temperature , D P 1 o coefficient. flow = = i T512 icagrcecetadits and coefficient discharger =  C 1 D − A C  = P P T o C  ≡ F ( A k E47(01 21 / 8 (2021) 417 ME 21 / 6 (2021) 417 ME T − S o 1 ) density , / k  # 1 / 2 ≡ ρ o e830 T513 © © ⊞ atclrpso pe.TeMc ubrfrta vrg ne gas that inlet at average gas that cylinder for be the number would of Mach speeds filling The inlet complete the realize speed. through to piston speed particular be gas to average have would the valve what characterizes it rather, speed; nae&ehutpr o coefficients flow port exhaust & Intake If r d auu a (BUET) Haq Zahurul Md. Dr. (BUET) Haq Zahurul Md. Dr. h ahidxi o aaee htcaatrzsteata gas actual the characterizes that parameter a not is index Mach The ( θ ic − θ io ) /π 1.3, = Z / 0 . 8for 58 e v = ouercEcec fEngines of Efficiency Volumetric Engines of Efficiency Volumetric 0 k . 75 1.4. = / Z e879 T514 offiin fdshreo nae& intake of discharge of Coefficient e vb xas ports exhaust = e v ( E47(01 21 / 9 (2021) 417 ME E47(01 1/21 / 11 (2021) 417 ME Z = 0 . 5 ) © © = ⇒ r d auu a (BUET) Haq Zahurul Md. Dr. (BUET) Haq Zahurul Md. Dr. • • • • • • • • • • urn rciedictates: practice Current ( lift and diameter valve exhaust smaller A If b If efficiency, volumetric good For η choked: always is η flow which in case limiting a In efficiency, Volumetric valve Inlet area, flow intake effective Average time, open valve during induced Mass eas ftesedo h on shge nteehutgssthan gases exhaust the in higher flow. is gas sound inlet the the of in speed the of because that so velocity, sonic choked. the not than is less flow be intake should the valve inlet the through v v niebore, engine = Z Z = = = = 0 ω A . 0 0 58 E V . . ,aeaeeetv rao xas valves, exhaust of area effective average 6, valves, intake of area effective average 6, c d i  ahIndex Mach ( θ θ ic ic − π − θ io s θ  ffc fIOIC&Egn pe on Speed Engine & IVO/IVC of Effect io toeand stroke = A Z 1 ) i η  ouercEcec fEngines of Efficiency Volumetric Engines of Efficiency Volumetric ≥ v , for k = Z 1 + 2 A A A . 3 ≡ k ρ e iigo nae&EhutValves Exhaust & Intake of Sizing e i 1 b / m i  V 2 ≃ A A A = i S Z d ( c P E i k i p c 1 c ≃ + N S = ≤ c e i . i p 1 A 4 ) . o0.8. to 0.7 = niesedi rev/s. in speed engine = 0 / ωρ E 2 . ( :teaeaegsspeed gas average the 6: m r ≡ k 1 i − i S V 1 T T θ = ) p d L ic e i v = Z ω − 1 θ 1 θ ∼ o hkdcondition choked for io ic 2 θ Z sN D md θ io θ ˙ io v ic / A Z md θ θ )cnb used be can 4) θ ˙ A i E47(01 2/21 / 12 (2021) 417 ME 21 / 10 (2021) 417 ME io ic is e A θ is E d θ ≡ C D A η C v e877 © © 00rm oeadsrk f01m n ne i eprtr f30K Assume, K? 330 of of temperature speed air maximum inlet and a with m, engine 0.1 an of k stroke for 0.6 and bore of rpm, index 8000 Mach a for required area ⊲ ⇒ ⇒ ⇒ ⇒ ⇒ ⇒ r d auu a (BUET) Haq Zahurul Md. Dr. (BUET) Haq Zahurul Md. Dr. = hti h naevlearea valve intake the is What 1 A A A A c S . i 4 p v p i i , = / = = = ( = R A √ C 1 p = 2 . π/ kRT sN = F 3 8 /gKadaeaeflwcoefficient, flow average and K J/kg 287 b A 4 2 2 v = ) S . o b 65

p 2 2 = / / ( = × c A 7 √ i . v 0 86 ffc f( of Effect = 1 π/ . = . 1 4 1 = 4 × . 2 × 3 )( . 0 65 ( × 287 0 . 8000 ouercEcec fEngines of Efficiency Volumetric Engines of Efficiency Volumetric 34 . 1 ( × 0 ) ⊳ A 2 . = 01 1 / i = ) 60 364 − 2 n h ai fitk av rat piston to area valve intake of ratio the and P 7 3 × = ) . i 85 m / 26 m 2 P 26 nrae othe volume so this increases As the varies. at pressure gas intake residual the by volume occupied cylinder the of fraction the of values As η / × / xml:Itk av Sizing Valve Intake Example: η s vb 364 e v 10 opeso ai ( Ratio Compression & ) m /η = − / = s vb 3 η m 9 v = . ( 3 2 P × 1 e . C / 0 P 10 P F e − − i / 0.35 = e 3 P = k 1 v i m E47(01 5/21 / 15 (2021) 417 ME 21 / 13 (2021) 417 ME h 1 decreases. and 2 P . 0 e ⊳ r . ) / c P − r i 1 c − 1 r varied, are i r c ) e762 © © uiiy ssal o aeu ul n o ehnlvapour, methanol (and for vapour and fuel fuels of gaseous effect For the small. gasoline is as humidity) such fuels liquid conventional For infiatyrdcdb h ulvpu nteitk mixture. intake the in vapour fuel the by reduced significantly r d auu a (BUET) Haq Zahurul Md. Dr. (BUET) Haq Zahurul Md. Dr. • • e896 case? each in speed piston maximum the is what Z f4 of ofiuain ssoni iueblw fteMc ne ncs shl to held is case in index Mach the If below. Figure in shown as configurations pe ti neddt eoeae hl anann odvolumetric good maintaining while operated be to efficiency? intended is it speed ⊲ ⊲ i fa niehsabr f01m toeo .8m ne o ffciearea effective flow inlet m, 0.08 of stroke m, 0.1 of bore a has engine an If aclt h aiso h ne av rat itnae o h 3 the for area piston to area valve inlet the of ratios the Calculate = . 0 0 × . 6 , 10 c i − = 4 m 400 2 n ne eprtr f30K hti h maximum the is what K, 320 of temperature inlet and m / s , A ouercEcec fEngines of Efficiency Volumetric Engines of Efficiency Volumetric i = orcinfrwtrvpu ssmall is vapour water for Correction P pressure. mixture the partial below air pressure the in reduces vapour system water intake & the fuel gaseous of Presence P P ffc fFe,PaeadHumidity and Phase Fuel, of Effect P P 0 a a i . i i , , 35 i i = = = n P i ( h h a π/ 1 1 , i ( + + + 4 ) d  P F i 2 f m m ( ˙ ˙ , / i n f a A   i + ) ubro naevalves), intake of number = P  oeokProblems Homework M M w M M f a , f a i   + + E47(01 6/21 / 16 (2021) 417 ME 21 / 14 (2021) 417 ME  1 m . m ˙ 6 ˙ w a    43 rpm) (4137 η m m ˙ ˙ v w a M M i is ≤ w a i − 0.03. 1 − 1 ⊳ e897 © © r d auu a (BUET) Haq Zahurul Md. Dr. (BUET) Haq Zahurul Md. Dr. • • • ulvpu:frsm etn rate, heating same for vapour: fuel yafwpercent. few a by oeta ffesterdcinin reduction the offsets than more xeietldt hwta eraein decrease that show prior data vaporized Experimental cylinder. completely the not to is entry fuel to also, occurs; heating practice, In with − iso-octane, of liquid evaporation as complete decreases φ For temperature mixture vaporized. mixture, is fuel to transfer heat no If 128 = 1 o . C. 0 , T 2 − T ffc fFe aoiain&Ha Transfer Heat & Vaporization Fuel of Effect 1 − = 19 ouercEcec fEngines of Efficiency Volumetric Engines of Efficiency Volumetric o .Frmtao,tmeauedpeso is depression temperature methanol, For C. .,4&6. & of 4 proportion 2.5, the in Reynold’s different are the numbers that fact the of spite ◮ e880 he nie tagvnvleof value given a at engines three osgicn ieec in difference significant No ffc fEgn ie&Speed & Size Engine of Effect P η a v , i ihfe aoiaini higher is vaporization fuel with u oteicesdaon of amount increased the to due T i u ofe evaporation fuel to due E47(01 9/21 / 19 (2021) 417 ME 21 / 17 (2021) 417 ME η v Z between in , © © iia engines Similar n ularrtowl aetesmlrvlmti ffiinywithin efficiency volumetric similar limits. the the temperature, measurable have at will coolant and ratio temperature, speed fuel-air inlet piston pressures, and mean exhaust of and values inlet same same the at running engines Similar r d auu a (BUET) Haq Zahurul Md. Dr. (BUET) Haq Zahurul Md. Dr. • • • • η ( Temperature Coolant of Effect η ( Temperature Charge Inlet of Effect alloy. steel alloy same aluminium the same of of are are crankshafts in pistons all example, the For and all parts. engines similar corresponding MIT in the used for are materials different is same drawings The the same of the from scale engine. built the are each only engines drawings, Similar detail of same. set the are ratios design All vb vb = = η η v v tbsln temperature, baseline at ( temperature, baseline at ( ffc fIltCag oln Temperatures Coolant & Charge Inlet of Effect nie hc aetefloigcharacteristics: following the have which engines : ouercEcec fEngines of Efficiency Volumetric Engines of Efficiency Volumetric η η vb v η η = vb v iiiuei i ytmDesign System Air in Similitude r = T r T c T T 1450 c + 330 c i ) T 3 K). 330 = : 4 K). 340 = 1110 i T i ) : E47(01 0/21 / 20 (2021) 417 ME 21 / 18 (2021) 417 ME © qualitatively. ◮ where, prto parameters: operation r d auu a (BUET) Haq Zahurul Md. Dr. 4 3 2 1 iesoa nlssi sdonly used is analysis Dimensional . . . T T P e c i η / : : = vb P = ⇒ i ⇒ r aeievlmti ffiinyotie o h e of set the for obtained efficiency volumetric baseline are : = K K ⇒ 2 3 = K = 1 q q η = v 330 T T 1 = c i 1450 . + 0 η 1110 − v ouercEcec fEngines of Efficiency Volumetric ( P k 1 η e h v / P P = e r / i c , P − η r i 1 oass h ffc faparameter a of effect the assess to − c vb , 1 T i Y i = N i , 1 T K c i , Z φ, , iesoa Analysis Dimensional · · · ) E47(01 1/21 / 21 (2021) 417 ME