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Reciprocating Internal Combustion Engines

Reciprocating Internal Combustion Engines 13
Reciprocating Internal Combustion Engines Prof. Rolf D. Reitz Engine Research Center University of WisconsinMadison 2014 PrincetonCEFRC Summer School on Combustion Course Length: 15 hrs (Mon. Fri., June 23 – 27, 2014) Copyright ©2014 by Rolf D. Reitz. This material is not to be sold, reproduced or distributed without prior written permission of the owner, Rolf D. Reitz. 1 CEFRC11, 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Short course outine: Engine fundamentals and performance metrics, computer modeling supported by indepth understanding of fundamental engine processes and detailed experiments in engine design optimization. Day 1 (Engine fundamentals) Part 1: IC Engine Review, 0, 1 and 3D modeling Part 2: Turbochargers, Engine Performance Metrics Day 2 (Combustion Modeling) Part 3: Chemical Kinetics, HCCI SI Combustion Part 4: Heat transfer, NOx and Soot Emissions Day 3 (Spray Modeling) Part 5: Atomization, Drop Breakup/Coalescence Part 6: Drop Drag/Wall Impinge/Vaporization/Sprays Day 4 (Engine Optimization) Part 7: Diesel combustion and SI knock modeling Part 8: Optimization and Low Temperature Combustion Day 5 (Applications and the Future) Part 9: Fuels, Aftertreatment and Controls Part 10: Vehicle Applications, Future of IC Engines 2 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Motivation Society relies on IC engines for transportation, commerce and power generation: utility devices (e.g., pumps, mowers, chainsaws, portable generators, etc.), earthmoving equipment, tractors, propeller aircraft, ocean liners and ships, personal watercraft and motorcycles ICEs power the 600 million passenger cars and other vehicles on our roads today. 250 million vehicles (cars, buses, and trucks) were registered in 2008 in US alone. 50 million cars were made worldwide in 2009, compared to 40 million in 2000. China became the world’s largest car market in 2011. A third of all cars are produced in the European Union, 50 are powered diesels.  IC engine research spans both gasoline and diesel powerplants. Fuel Consumption 70 of the roughly 86 million barrels of crude oil consumed daily worldwide is used in IC engines for transportation. 10 million barrels of oil are used per day in the US in cars and lightduty trucks 4 million barrels per day are used in heavyduty diesel engines, total oil usage of 2.5 gallons per day per person. Of this, 62 is imported (at 80/barrel costs US economy 1 billion/day). 3 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling US energy flow chart 18 World energy use = 500 x 10 J 14EJ 23EJ 23EJ 70 of liquid fuel used for transportation 28 of total 40EJ US energy consumption http://www.eia.gov/totalenergy/ 18 100x10 J 4 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Fuel consumption CO emissions 2 World oil use: 86 million bbl/day = 3.6 billion gal/day (0.6 gal/person/day) Why do we use fossil fuels (86 of US energy supply) Large amount of energy is tied up in chemical bonds. Consider stoichiometric balance for gasoline (octane) in air: 6 C H + 12.5(O +3.76N )  8CO + 9H O+47N (+ 48x10 J/kg ) 8 18 2 2 2 2 2 fuel Kinetic energy of 1,000 kg automobile traveling at 60 mph (27 m/s) 2 2 2 6 = 1/2·1,000·27 (m kg/s =Nm) 0.46x10 J = energy in 10g gasoline 1/3 oz (teaspoon) Assume: 1 billion vehicles/engines, each burns 2.5 gal/day (1 gal 6.5lb 3kg) 9 6 18  7.5x10 kg /day48x10 J/kg=360x10 J/yr fuel 1 kg gasoline makes 8·44/114=3.1 kg CO 2 9 9 9 365 · 7.5x10 kg /yr 8,486x10 kgCO /year 8.5x10 tonneCO /year fuel 2 2 9 (Humans exhale 1 kgCO /day = 6x10 kgCO /year) 2 2 18 Total mass of air in the earth’s atmosphere 5x10 kg So, CO mass from engines/year added to earth’s atmosphere 2 12 18 8.5x10 / 5x10 1.7 ppm 5 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling 1 (Prof. John Heywood, MIT) Modern gasoline IC engine vehicle converts about 16 of the chemical energy in gasoline to useful work. The average lightduty vehicle weighs 4,100 lbs. The average occupancy of a lightduty vehicle is 1.6 persons. If the average occupant weighs 160 lbs, 0.16x((1.6x160)/4100) = 0.01 6 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Pollutant Emissions 37 billion tons of CO (6 tons each for each person in the world) from fossil fuels/yr, 2 plus other emissions, including nitric oxides (NOx) and particulates (soot). CO contributes to Green House Gases (GHG), implicated in climate change 2 drastic reductions in fuel usage required to make appreciable changes in GHG CO emissions linked to fuel efficiency: 2 automotive diesel engine is 20 to 40 more efficient than SI engine. But, diesels have higher NOx and soot. serious environmental and health implications, governments are imposing stringent vehicle emissions regulations. diesel manufacturers use Selective Catalytic Reduction (SCR) aftertreatment for NOx reduction: requires reducing agent (urea carbamide) at rate (and cost) of about 1 of fuel flow rate for every 1 g/kWh of NOx reduction. Soot controlled with Diesel Particulate Filters (DPF), requires periodic regeneration by richening fuelair mixture to increase exhaust temperature to burn off the accumulated soot imposes about 3 additional fuel penalty. Need for emissions control removes some of advantages of the diesel engine 7 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Goal of IC engine: Convert energy contained in a fuel into useful work, as efficiently and cost effectively as possible. Identify energy conversion thermodynamics that governs reciprocating engines. Describe hardware and operating cycles used in practical IC engines. Discuss approaches used in developing combustion and fuel/air handling systems. Internal Combustion Engine development requires control to: introduce fuel and oxygen, initiate and control combustion, exhaust products IC engine Heat (EC) engine (Not constrained by (Carnot cycle) Energy release occurs Internal Carnot cycle) Energy release to the system. occurs External Working fluid Heat source Oxygen to the system. undergoes state (P,T) and chemical Working fluid undergoes changes Work Work reversible state during a cycle changes (P,T) Heat sink Fuel Combustion products during a cycle (e.g., Rankine cycle) 8 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Components of piston engine Piston moves between Top Dead Center (TDC) and Bottom Dead Center (BDC). Compression Ratio = CR = ratio of BDC/TDC volumes Stroke = S = travel distance from BDC to TDC Bore = B = cylinder diameter D = Displacement = (BDCTDC) volume. cylinders 2 = p B S/4 . cylinders Basic Equations P = W.N = T.N P kW = T Nm.N rpm.1.047 E04 BMEP = P.(rev/cyc) / D.N BMEP kPa = P kW.(2 for 4stroke) E03 / D l. N rev/s . BSFC = m / P fuel . BSFC = m g/hr / P kW fuel P = (Brake) Power kW Brake = gross indicated + pumping + friction T = (Brake) Torque Nm = Work = W BMEP = Brake mean effective pressure = net indicated + friction . m = fuel mass flow rate g/hr fuel BSFC = Brake specific fuel consumption 9 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Engine Power Heywood, 1988 Indicated power of IC engine at a given speed . is proportional to the air mass flow rate, m air . P = h . m N. LHV . (F/A) / n f air r h = fuel conversion efficiency f LHV = fuel lower heating value F/A fuelair ratio m /m f air n = number of power strokes / crank rotation r = 2 for 4stroke Efficiency estimates: SI: 270 bsfc 450 g/kWhr Diesel: 200 bsfc 359 g/kWhr h = 1/46 MJ/kg / 200 g/kWhr = 4050 f 500 MW GE/Siemens combined cycle gas turbine natural gas power plant 60 efficient SGT58000H 530MW 10 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling 4stroke (Otto) cycle “Suck, squeeze, bang, blow” 1. Intake: piston moves from TDC to BDC with the intake valve open, 180 BDC W  pdv pdv drawing in fresh reactants in,gross  180 BDC 2. Compression: 3 valves are closed and piston moves from BDC to TDC, (net = gross + pumping) Combustion is initiated near TDC 3. Expansion: W pdv high pressure forces piston in,net  from TDC to BDC, transferring work to crankshaft 2 4. Exhaust: exhaust valve opens and piston moves 1 4 from BDC to TDC pushing out exhaust 1,4 Pumping loop – An additional TDC BDC rotation of the crankshaft used to: Fourstroke diesel pressurevolume exhaust combustion products diagram at full load induct fresh charge 11 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Combustion process initiated near end of compression stroke. Instantaneous combustion has high theoretical efficiency, but is impractical due to need to manage peak pressures and due to high heat transfer. Sparkignition engine: mixture of air (oxygen carrier) and fuel enters chamber during intake process. Mixture is compressed combustion initiated using a highenergy electrical spark. Compressionignition (Diesel) engine: air alone is drawn into chamber, compressed. Fuel injected directly into chamber near end of compression process. (Fuel used in compressionignition engine must easily spontaneously ignite when exposed to high temperature and pressure compressed air.) Diesel is often portrayed as having a slower combustion process (constant pressure instead of constant volume) Goal of rapid combustion near TDC for maximum efficiency is true for both Diesel and sparkignition engines. 12 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Heywood, 1988 Thermodynamics review – Zero’th law 1. Systems in thermal equilibrium are at the same temperature 2. If two thermodynamic systems are in thermal equilibrium with a third, they are also in thermal equilibrium with each other. B 300K A 300K Thermal equilibrium 300K C 13 CEFRC11 2014 = system Part 1: IC Engine Review, 0, 1 and 3D modeling Heywood, 1988 Thermodynamics review First law During an interaction between a system and its surroundings, the amount of energy gained by the system must be exactly equal to the amount of energy lost by the surroundings Engine System Surroundings Gained (input) (J) Lost (output) (J) Work Gained (J) Intake flow + Heat Lost (Cylinder wall, Lost (J) Energy of fuel Exhaust gas ) combustion Friction 14 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Heywood, 1988 Thermodynamics review Second law The second law asserts that energy has quality as well as quantity (indicated by the first law)  q ds ds irrev T ds 0 irrev Engine research: Reduce irreversible Increase thermal losses efficiency 15 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Heywood, 1988 Equations of State where Thermal: R R /W Pv RT u Caloric: de c dT and dh c dT p v Enthalpy: h e Pv c  R R p c Ratio of specific heats:  c p v 1 c1 v Calculation of Entropy 2 Tds de vdP Gibbs’ equation: P TP 22 1 s s c ln R ln 21 p TP 11 and Tv 22 s s c ln Rln 21 v Tv v 11 16 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Heywood, 1988 Isentropic process Adiabatic, reversible ideal reference process TP 22 0 s s c ln R ln 21 p TP 11  /(1)  p v T 2 1 2   p v T 1 2 1 Tv 22 0 s s c ln R ln 21 v 2 Tv 11 P 1 v 17 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Heywood, 1988 Ideal cycles Diesel Otto T T 3 3 2 2 1 1 4 4 s s 12 Isentropic compression 12 Isentropic compression 23 Constant volume heat addition 23 Constant pressure heat addition 34 Isentropic expansion 34 Isentropic expansion 41 Constant volume heat rejection 41 Constant volume heat rejection 18 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Constant volume combustion HCCI: T t t begin end T burn Isentropic During constant volume expansion combustion process: t 1100K t 0 begin end 800K t end W Pd 0 Shaft  Motored t Isentropic begin compression t end TDC Q Qdt mQ f LHV  t begin  (1) T  T m Q burn unburn f LHV R 19 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Heywood, 1988 8 ZeroDimensional models measured 7 predicted 6 5 4 measure Single zone model 3 p() 2 V() 1 st 1 Law of Thermodynamics 0 80 60 40 20 0 20 40 60 80 Crank Angle, deg. dT dV  mc p m hq qq  v j j Comb Loss Net dt dt j 350 300 Use the ideal gas equation to relate p V to T 250 dV 1 dpV 200 qp Net dt 1 dt 150 100 where qhA(T T ) 50 Loss wall 0 50 Assume h and T wall 20 10 0 10 20 30 40 50 60 Crank angle (degree) 20 CEFRC11 2014 Heat release rate (J/degree) Pressure, MPaPart 1: IC Engine Review, 0, 1 and 3D modeling 1D Models 1D codes (e.g., GTPower, AVLBoost, Ricardo WAVE) predict wave action in manifolds At high engine speed valve overlap can improve engine breathing  inertia of flowing gases can cause inflow even during compression stroke. Variable Valve Actuation (VVA) technologies, control valve timing to change effective compression ratio (early or late intake valve closure), or exhaust gas reinduction (rebreathing) to control incylinder temperatures. Residual gas left from the previous cycle affects engine combustion processes through its influence on charge mass, temperature and dilution. L t=L/c=1 m/330 m/s = 3 ms AVL Boost, Ricardo WAVE, GTPower 1 ca deg = 0.1 ms 1800 rev/min 21 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Anderson, 1990 Control volumes and systems 22 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Anderson, 1990 1D compressible flow Reynolds Transport Equation dMg d d )gdgdgVn dA system rel Mass conservation:  cv cs dt dt dt system g 1 dMg / dt) 0 dx System Divergence theorem cv fixed () A  d Adx 0 AV dx    cv t  Supplementary:  ( A) ( AV )  0 1. 4. P=RT  tx State Momentum conservation: e=c T 5. v VV 1P 2 2 2. V 2 fV / D 0 fVt / / 2 w txx Q q Adx Energy conservation: ee P() VA 3 V q2/ fV D 3. 5 unknowns U: , V, e, P, and T tx Ax 5 equations for variation of flow variables in space and time Need to evaluate derivatives  /xt , / 23 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Numerical solutions n U i Dx To integrate the partial differential equations: i Discretize domain with step size, Dx Time marches in increments of Dt from 0 n n n n n i = 1, 2, 3, 4, …….. , M1, M initial state U : ,V ,e , P ,and T i i i i i i t=nDt n=0, 1, 2, 3, .... nn U(x,t)DU(x ,ndt) UU i i1 i  xDxDx ii nn1 U(x,t)DU(x ,ndt) UU i i i  tDtDt Considerations of stability require the CourantFriedrichsLevy (CFL) condition nn Dt min(Dx /(V c ) i i i 24 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Anderson, 1990 Analytical solutions – Method of Characteristics dx Wave diagram R: rightrunning wave slope  Vc dt V L: leftrunning wave P: particlepath dx dx slope  Vc  V slope dt dt V x – distance along duct All points continuously receive information about both upstream and downstream flow conditions from both left and rightrunning waves. These waves originate from all points in the flow. 25 CEFRC11 2014 t time Part 1: IC Engine Review, 0, 1 and 3D modeling Anderson, 1990 Analytical solutions – Method of Characteristics dx Wave diagram R: rightrunning wave slope  Vc dt V L: leftrunning wave P: particlepath dx dx slope  Vc  V slope dt dt Dt V Dx x – distance along duct nn Dt min(Dx /(V c ) R:, L:, P:, are called Characteristic Lines in the flow i i i 26 CEFRC11 2014 t time Part 1: IC Engine Review, 0, 1 and 3D modeling Moody, 1989 2 Along L: Along P: d dp / c Hdt Along R: dPcdV Gdt dPcdV Fdt F,G, H Functionsof q, f ,ln A/ dx  t The discrete versions are: dx n P: Slope  V P (P P ) (c) (VV ) FDt 44 R R R R dt dx nn Slope  Vc LL (P P )(c) (VV ) GDt dt 44 L L L L Dt dx nn 1  Slope  Vc ( ) (P P ) HDt RR 44 P  P P 2 dt c  P 4 Time level n+1 3 equations to solve for 1 2 3 Time level n  ,VP and 4 4 4 L R P (Solution variables x known) Note: from Gibbs’ equation Dx c dP c PP dS() d Hdt 2 V  c 27 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Moody, 1989 Anderson, 1990 Analytical solutions – Method of Characteristics In the special case of isentropic flow, F=G=H=0, and P: equation is not needed dP/0c dV : along R and L characteristic lines Integrating gives MV / c t dP 2 V J cV RL ,  dx  c1 n P: Slope  V P dt dx nn Slope  Vc LL where J are the Riemann Invariants dt R,L Dt dx nn (2 equations in 2 unknowns) Slope  Vc RR dt or, along R: 4 Time level n+1 2 V c J R 1 2 3 1 Time level n L R P x and along L: 2 V c J L Dx 1 When Vc “leftrunning” wave’s slope 0, V and information does not propagate upstream 28 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Moody, 1989 Anderson, 1990 Analytical solutions – Method of Characteristics Example: A weak wave with pressure ratio P /P =1.25 propagates down a tube filled with air 2 1 at rest with T = 500K and P =500 kPa. 1 1 Find the gas velocity behind the wave using MOC.  For isentropic flow: c RT 1.4287500 448.2m/ s 11 (1)/ 2 Conditions known at state 1 c / c (P / P) t 2 1 2 1 =0 2 22 V c J V c Along L: 1 1 L 2 2   11 1  V 72.6m/ s 2 x 1 2 wave 29 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Thompson, 1972 Lagrange ballistics Flow velocities in IC engine cylinders are usually than the speed of sound. Lagrange ballistics shows that cylinder pressure and density is the same at all points within the combustion chamber. P P (c) (0V ) L: 4 L L L head R: P P (c) (VV ) 4 R R piston R X 2  (P P ) / c ) P: 44 P P P V piston Pressure increases by dP each wave reflection (dV0) x dx Slope V in order to alternately ensure that the flow meets the piston t dt boundary conditions: V=0 at head, and V=V piston at piston. Order of magnitude analysis of L:, R:, and P: gives d dV and dP cdV x  c For dVc relative density change is small– so density changes only in time 30 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Thompson, 1972 Lagrange ballistics  (x,t) (t) head X V piston x Mass conservation shows that dV  V 0 dt  x x x VV Gas stretches linearly piston X Momentum conservation gives 2 P(x,t) P(x 0,t)Xx / 2X or P=P(t) as long as piston acceleration is small X Location of pressure transducer unimportant 7/11/2014 31 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Gas exchange process p p in ex Gasoline engine intake system: Co Co Com m mbustion bustion bustion air filter, carburetor and throttle plate or port fuel injector, intake manifold, intake port, intake valves. Cylinder Cylinder Cylinder Cylinder Co Co Com m mbustion bustion bustion pressu pressu pressu pressure re re re blowd blowd blowd blowdown own own own Supercharging – increases inducted air mass com com com comp p p pressi ressi ressi ressio o o on n n n (in both gasoline and diesel engines). Li Li Li Lift ft ft ft Intake and exhaust manifold designed to maximize cylinder filling and scavenging. Exh Exh Exh Exhaust aust aust aust Intake Intake Intake Intake Intake system pressure drops (losses) occur due BDC BDC BDC BDC TDC TDC TDC TDC BDC BDC BDC BDC TDC TDC TDC TDC overlap overlap overlap overlap to quasisteady effects (e.g., flow resistance), and unsteady effects (e.g., wave action in runners). Engine breathing affected by intake/exhaust valve lifts and open areas (most of the losses). Valve overlap can cause exhaust gases to flow back into intake system, or intake gases can enter the exhaust (depending on p / p ) in ex Intake also generates large scale flow structures Swirl and tumble that can be used to promote turbulent mixing flows requires 3D CFD modeling 32 CEFRC11 2014 Cy Cy Cy Cyl l l li i i in n n nd d d der er er er Pres Pres Pres Pressure, Valv sure, Valv sure, Valv sure, Valve Li e Li e Li e Lif f f ft t t tPart 1: IC Engine Review, 0, 1 and 3D modeling In 1D models friction factors are used to account for losses at area change or bends by applying a friction factor to an “equivalent” length of straight pipe R Flow losses Apply experimentally or numerically determined Loss Coefficient to equivalent straight pipe 2 D PCV /2 P 33 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Ricardo WAVE friction models http://www.ricardo.com/enGB/Whatwedo/Software/Products/WAVE/ 34 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Ricardo WAVE valve model Experimentally measured flow profiles 35 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Optimization: Volumetric efficiency MercedesBenz three stage resonance intake system 36 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Heywood, Fig. 6.9 Volumetric efficiency parameters (SI engine CI engine) A  B  C  D  E  F  G Losses in Carburetor, Intake manifold heating (rho), Fuel vapor displaces air MAP PinPex in diesel Lower CR SI more residual Diesel more residual is air 37 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Volumetric efficiency Accurate descriptions of valve flow losses require consideration of multidimensional flow separation phenomena and their effect initial conditions at intake valve closure (IVC). Highest mixing of incoming fresh charge and combustion products occurs when intake flow velocities are CFD flow velocity and residual gas distribution largest due to high flow during gas exchange in plane of valves turbulence (halfway through (intake valves about to close stroke). 144 degrees ATDC 1600 rev/min) 38 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Brief history of engine CFD Arab oil crisis 1973: US DOE • Open source codes – Los Alamos National Lab, Princeton Univ., UWERC – 1970’s – RICE  REC  APACHE  CONCHAS – 1980’s – CONCHASSPRAY  KIVA family – 1985 – KIVA ;1989 – KIVAII; 1993 – KIVA3; – 1997 – KIVA3V; 1999 – KIVA3V Release 2; 2006 KIVA4 – 2004 – OpenFOAM (2011 SGI) • Commercial codes – 1980’s Imperial College others – Computational Dynamics, Ltd.  commercialize: STARCD – 1990’s—other commercial codes: AVL FIRE, Ricardo VECTIS – 2005– FLUENT (with moving piston and incylinder models) – 2010 – CONVERGE (CSI), FORTE (Reaction Design)….. Annual IMEMUser group meeting: Cray/UWERC/Iowa State SAE Congress Multidimensional Modeling Session….. 39 CEFRC11 2014 Amsden, 1989, 1997 Part 1: IC Engine Review, 0, 1 and 3D modeling 3Dimensional models Solve conservation equations on (moving) numerical mesh Mass spray source terms Species Momentum combustion source terms Energy 40 CEFRC11 2014 Amsden, 1989, 1997 Part 1: IC Engine Review, 0, 1 and 3D modeling KIVA3V CFD code: flow solver Main program and approximately 50 subroutines Initialization Read input data Calculate gas viscosity Initialize time step, piston velocity Phase A Spray modeling (injection, drop breakup, collision, evaporation…) Combustion chemistry Big Iteration Emission modeling Mass and energy contribution due to spray and combustion Phase B Fluid phase calculation Mass, momentum, velocity, temperature, pressure, turbulence properties (Implicit solver, iterations) Update droplet velocity Phase C “Snapper” Snapping/Rezoning grids add/delete grid cells Remapping fluid properties to new grids Update cell properties 41 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling IPCC, 2014 Summary – CO = fuel efficiency 2 50 of cumulative anthropogenic CO emissions between 1750 and 2010 2 have occurred in the last 40 years transportation 42 CEFRC11 2014 Part 1: IC Engine Review, 0, 1 and 3D modeling Charmley, 2004 Summary Transportation is 1/3 of the total energy use in the US Internal combustion engines are among the most efficient power plants known to man, but research is needed to improve them further The industry faces significant challenges to meet emissions regulations, but great progress has been made in the last 20 years. Modeling tools are available to help quantify engine performance and to provide directions for improved efficiency US HD emissions regulations Oil Consumption, 2010: US 21.1 Total Europe Eurasia 22.9 China 10.6 43 CEFRC11 2014
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