Internal Combustion Engines PDF 2024/2025

Internal Combustion Engines ICENG - Master M-Eng-EP - 2024/2025 - X. Tauzia [email protected] 2  3 Table of content...

Internal Combustion Engines ICENG - Master M-Eng-EP - 2024/2025 - X. Tauzia [email protected] 2  3 Table of contents 1. Introduction p. 6 2. Technology p. 17 3. Engine geometry and Performances Indicators p. 45 4. Applications p. 118 5. Intake and exhaust systems p. 207 6. Charging system p. 269 7. Fuel induction p. 320 8. Combustion p. 378 9. Pollutant emissions p. 421 10. Cooling p. 483 11. Lubrication and friction p. 501 12. Electronic management p. 518 13. References p. 523 14. Exercises p. 525 4 Warning This document is left uncomplete on purpose. It is only a support for taking notes. During the oral presentation, explanations and supplementary data will be presented. Moreover it is only an introduction to Internal Combustion Engines. Additional references are given in the various chapters and at the end of the book for further deepening. Some are available on the “serveur pédagogique” https://hippocampus.ec-nantes.fr/. Finally, despite the care taken in writing, some errors and typos probably remain; Thanks to all students who will contribute to the continuous improvement of this book by helping me correct them.  5 1867 2018 P=0.37 kW P=125 kW h=12% h=41% Emission ? Euro6d SWOT Analysis Strength Weaknesses Internal Opportunities Threats External 6 1. Introduction Definition Historical perspective Various engine types Theoretical cycles  7 Introduction Engine : aims at producing mechanical work converting energy initially under another form Historically : animals, water mills, wind mills: natural, renewable sources, from the sun Combustion machines : use chemical energy contained in fossil fuels (oil, gas, coal) or extracted from biomass (renewable) Steam Machine (papin) Internal combustion engine(Otto) Doc: visite.artsetmetiers.free.fr Docs: wikipedia Doc. wired.com 8 Introduction Electric motors: use electric energy which must be produced, usually from mechanical work, with various sources, renewable or not (hydraulic, Combustion machine, nuclear reactor…) Docs. Wikipedia, cprmotor.com Electic motor (Davenport) early 19th century  9 Introduction Nuclear Energy Photosynthesis Sun Chemical energy photovoltaic Ocean Water Wind currents Cycle Fuel Cell Heat Electrolysis Seebeck effect Wind turbine Water Electric Energy Electric Internal External turbine Motor Combustion combustion engine Current Engine turbine Alternator Mechanical Energy Propulsion machines 10 Introduction Combustion engines: Most often, a fluid is submitted to several processes, in a cyclic manner (thermodynamic engine cycle) If the combustion happens within the fluid : internal combustion (piston engines, Gas Turbines GT, turbojets..) Otherwise : external combustion engine (ex : Stirling or Ericsson engine, Rankine or Hirn cycles,..) This lecture is about reciprocating piston internal combustion engines (Moteurs à combustion interne, moteurs alternatifs, moteurs à piston ). GT are not included. Rotative engines (moteurs «à pistons rotatifs» ) like Wankel engines are not explicitly included but they are quite similar with reciprocating piston engines. A lot of peculiar engines have been imagined, only a few being effectively developed. Most of times, only prototypes were built, or low volume production. Doc Enciclopedia britanica ,mit.edu, Wikipedia, absoluteastronomy.com; reviews.carreview.com Supplementary material on hippocampus Animations : www.animatedengines.com/index.shtml  11 Theoretical cycles Otto cycle, also called Beau de Rochas (French, first patent) : Doc. Grc.nasa.gov Thermodynamic cycle calculations: https://www.engr.colostate.edu/~allan/thermo/page1/page1f.html 12 Theoretical cycles Cycle Diesel : Idem Otto except: isobaric combustion Doc. wikipedia  13 Theoretical cycles Dual cycle (Sabathé) : Idem Otto except for: isochoric then isobaric combustion Doc. wikipedia 14 Different types of engines Gasoline/Petrol or Diesel ? For fuel induction and combustion several options : Spark ignition (SI) (with a spark plug, bougie d’allumage) for «gasoline» engines (but also for gas) or compression ignition (CI) (spontaneous ignition when temperature and pressure are high enough, allumage par compression) for Diesel engines Preparation of Fuel/air mixture outside of the cylinder then aspirated in the cylinder (SI engine using carburetors or external injection) or aspiration of pure air during the intake stroke followed by fuel introduction directly in the combustion chamber (All Diesel engines and Gasoline direct injection GDI IDE) or a combination of both solutions (dual-fuel engines, DF, for some industrial engines) The difference between the two types of engines is progressively reduced, in particular in new combustion concepts involving homogenous mixture and compression ignition such HCCI or SPCCI Combustion SPCCI (Spark Controlled Compression Ignition) moteur Mazda Sky Activ X (2020)  Summary 15 An engine produces mechanical work from an energy source initially under another form Internal combustion engines (ICE) appears at the end of 19th century and progressively replaces steam engine It uses chemical energy contained in the fuel Today, it is one of many machines allowing energy conversion, some of which are competitors, some others being complementary ICE rely on two theoretical cycles: Otto and Diesel ICE may be classified depending on ignition system : Spark ignition («gasoline») and compression ignition (« Diesel ») MCQ 16 True False Piston engines are always internal combustion engines ❒ ❒ Internal combustion engines always use pistons ❒ ❒ Internal combustion engines always reject heat ❒ ❒ Steam engines are Internal Combustion Engines ❒ ❒ Seebeck effect allows to: ❒ directly convert heat into electricity ❒ directly convert chemical energy into electricity ❒ directly convert mechanical work into electricity In Otto cycle, the following strokes are adiabatic : ❒ compression ❒ combustion ❒ expansion ❒ Heat rejection In Diesel cycle, the following strokes are adiabatic : ❒ compression ❒ combustion ❒ expansion ❒ Heat rejection  17 2. Technology Main parts Engine architectures Different types of engines 18 Technology Engine main parts volume variations are achieved with a piston (piston) moving up and down in a cylinder (cylindre). This receprocating motion is converted into linear motion with a connecting rod (bielle) and crankshaft (vilebrequin ). Intake and exhaust operations are achieved opening and closing at the right time valves (soupapes), actuated by the camshaft (arbre à cames). Doc www.quora.com  19 Technology Connecting rods - Pistons Pistons are usually made of light alloy and connecting rods are made of steel Sealing of combustion chamber is achieved with rings (segments) Doc. Automotive technology pearson slideshare.net, wheelzine.com, moodlecp9a 20 Technology Connecting rods Doc. Auto-innovations.com  21 Technology Pistons, rings Doc. Enginebuildermag.com Doc. Auto-innovations.com, renault, ohsmotorsport,mazda 22 Technology Diesel Pistons Doc. Auto-innovations.com, renault, mazda  23 Technology Crankshaft Doc. Bsnindustry.com Doc. Cr4.globalspec.com Doc. Rectimo-industrie.com Doc. www.dhidcw.com Doc. www.forum-auto.com The crankshaft is usually made of steel and mounted on fluid bearings (sometimes roller bearings) Complements: https://www.mahle.com/en/news-and-press/press-releases/piston-technology-for-modern-combustion-engines-388 http://www.federalmogul.com/en-US/OE/Leading-Technologies/Documents/03_March_Pistons_Engine%20Technology%20International.pdf 24 Technology Cylinder head Doc. Pkoemparts.nl Cylinder head (culasse), located above cylinders, usually contains Valves and the combustion chamber roof; it is connected to intake and exhaust runners; usually made of light alloy; for larger engines each cylinder has its own cylinder head Sealing between cylinder head and engine block relies on head gasket Docs. shadetreespeedshop.com, www.mgcontac.free.fr, wikepedia,www.autorepair.about.com, techno-siences.net  25 Technology Engine block – cylinders liners Docs. www.pierburginc.com, www.allproducts.com Engine block or cylinder block (bloc) is usually made of cast iron or light alloy. Cylinders liners are either directly machined in the block, or removable (chemise amovible) 26 Technology Engine block – cylinders liners Docs. www.pierburginc.com, www.allproducts.com  27 Technology Engine block – cylinders liners Docs. K. Hoag UniV Wisconsin, www.auto-innovations.com Compléments: Dossier «Fonctionnement, architecture et technologie des moteurs d'automobile 2ème partie :bloc moteur, cylindres et paliers» sur www.auto-innovations.com 28 Engine architectures Cylinders architecture Most of engines have several cylinders which cycles are time delayed (ideally with an identical delay but not always !) so that there is always at least one cylinder under power stroke (This requires 4 cylinders for a 4 stroke engine) The cylinders geometrical layout depends on constrains, in particular regarding engine volume : in line, V (2 connecting rods per crankpin), flat (boxer), etc.. Firing order et cylinders layout both influence engine vibrations. Docs. www.forum-auto.com, directory.oemoffhighway.com, us1.webpublications.com.au, trr.homeunix.org,  29 Engine architectures Engine balance Vibrations are caused by reciprocating (piston) and rotational (crankshaft) motions Forces and momentum are caused by in-cylinder gas pressure as well as mechanical inertia To optimize engine balance, firing order, cylinder layout (ex: V angle), and crankshaft design (ex: split crankpins) Balance shafts, driven by the engine can be used to reduce vibrations Some engines use peculiar architectures, quite different from theoretical optimal architectures (ex: narrow V engines) 30 Engine architectures Crankshaft balance Crankshaft with counterweights Crankshaft with split crankpins Doc. Wikimedia, www.e31.net  31 Engine architectures Balance shafts Docs. www.histomobile.com, MTZ 32 Engine architectures Crankshaft rotating assembly balance Application Configuration Combustion 1st order 2nd order 1st order 2ndorder interval forces forces torque torque 1 720 deg N N Y Y 2 in line 360 deg N N Y Y 2 in line (2S) 180 deg Y N N Y 2 boxer 360 deg Y Y N N 3 in line 240 deg Y Y N N 4 boxer 180 deg Y Y Y N 4 in line 180 deg Y N Y Y 5 in line 144 deg Y Y N N 6 in line 120 deg Y Y Y Y V6 60 deg 120 deg Y Y N N V6 90 deg 150 deg/90 deg Y Y N N V6 90 deg 120 deg Y Y N N 6 boxer 120 deg Y Y Y Y V8 90 deg 90 deg Y Y Y Y V10 72 deg 72 deg Y Y N N V12 60 deg 60 deg Y Y Y Y Y: balanced; N: unbalanced; Doc. www.auto-innovations.com Complements: www.autozine.org/technical_school/engine/smooth1.htm /www.e31.net/engines_e.html Mémento Bosch, chapitre « Equipage mobile du moteur à piston alternatif » Cours H Jeanmart, UCL, cours 6, www.icampus.ucl.ac.be/claroline/course/index.php?cid=MECA220  33 Engine architectures Peculiar architectures : W engine Doc www.auto-innovations.com W8 Engine (VAG) Crankshaft with split crankpins; 2 balance shafts Complements: www.auto-innovations.com, dossier «VR5, VR6, W8, W12 et W16 : des configurations moteurs audacieuses signées VAG » http://partsolutions.com/engineering-hall-of-fame-the-volkswagen-w-engine-and-the-bugatti-w16/ 34 Different types of engines 2 stroke/ 4 stroke? In standard « 4 stroke » engines (4 temps) a cycle is composed of 4 piston strokes (2 revolutions : 2 up and down travels) : - Intake (piston moves down) - Compression (piston moves up) - Combustion-expansion (piston moves down) - Exhaust (piston moves up) The same opeartions can be achieved in a single revolution, i.e. Two strokes: « 2 stroke » engine (2 temps) : - compression (end of moving up) - Combustion-expansion(begin of moving down) then exhaust and intake (end of moving down and begin of moving up)  35 Différents Differenttypes typesde of moteurs engines 2 stroke engine 2 stroke engines can be more or less complex A first compression can be achieved below the piston (in the engine crankcase which volume is minimized) then the fresh gas is transferred into the combustion chamber, through the transfer port. Pre compression before Intake can be achieved with an external compressor Scavenge (balayage) is critical Exhaust gases can go through exhaust ports or exhaust valves. Doc: washingtonpost, www.howstuffworks.com, www.mh7precisionengineering.co.uk, achatespower 36 Différents Differenttypes typesde of moteurs engines 2 stroke engines Advantages : - high specific power (relative to weight and size) because one power stroke per revolution - less friction (2 strokes per cycle instead of 4) - simple (no valve, no camshaft, less moving parts) : low cost; Drawbacks: - poor volumetric efficiency - high pollutant emissions (scavenge) - lubrication with oil-fuel mixture ➨ It is possible to solve these problems but this increases complexity and cost Doc: dieselduck.ca, visual.merriam-webster.com, mechanics.stackexchange.com  Application 37 P,v Diagram of a two stroke engine 38 Différents Differenttypes typesde of moteurs engines Peculiar architectures : opposed piston engines Already used in the past 2 stroke engine Less moving parts (no camshaft, no valves) Well balanced Compact, light Several possible configurations: 1 or 2 crankshaft,… Developed by several companies: ecomotors, achatespower, pinacle engines Doc: wikipedia, eco motors  39 Different types of engines Peculiar architectures: free piston engines highly simplified mechanism (no connecting rod, no crankshaft) Could be used for power generation (generator) Control is difficult Doc: toyota, treehugger.com 40 Engine parts Main parts of an automotive Diesel engine Doc. Renault  41 Engine parts Main parts of an automotive SI engine Doc. Auto.lapresse.ca 42 Engine parts Main parts of a two stroke Diesel industrial engine Doc. Auto.lapresse.ca  Summary 43 Main engine parts are: pistons, connecting rods, crankshaft, ebgine block, cylinders, cylinder head, camshafts, valves Main engine layouts are: in line, V and flat engines. Engine vibrations depend on its architecture and firing order. They can be reduced thanks to balance shafts «4 stroke» and «2 stroke» are two types of engines MCQ 44 A balance shaft: ❒ Increases engine performances ❒ Increases engine efficiency ❒ Increases comfort In a «4 stroke» engine, the camshaft rotates : ❒ At the same rotation speed as the crankshaft ❒ At half the rotation speed of the crankshaft ❒ At twice the rotation speed of the crankshaft ❒ At 4 times the rotation speed of the crankshaft In an IC engine, rings are : ❒ Located on the crankshaft and are linked to the connecting rods ❒ Pins liking pistons and connecting rods ❒ Elastic rings ensuring a good sealing between piston and cylinder ❒ Made of rubber A «2 stroke» engine : ❒ Sometimes uses valves ❒ Never uses valves ❒ Always uses valves ❒ Does not have neither intake nor exhaust processes  45 3. Engine geometry and operating parameters Engine geometry Real cycles, orders of magnitude Performances Efficiency 46 Engine geometry Piston oscillates between entre le Bottom Dead center (BDC) (Point mort bas, PMB) and Top Dead Center TDC (Point mort haut PMH) volume between BDC and TDC is called swept volume or displacement V (Cylindrée). Vd=p*B2*S/4, with: B the Bore (alésage) i.e. the cylinder diameter and S the Stroke (course) the length between BDC and TDC The remaining volume (above the piston) at TDC: the clearance volume or dead volume vc (volume mort). The ratio (Vd+vc)/vc : (Volumetric) compression ratio, (rapport volumétrique ou taux de compression). If B/S=1: square engine; If B/S>1 over square engine, Si B/S