Lecture-1 Prepared under QIP-CD Cell Project

Internal Combustion Engines

Ujjwal K Saha, Ph.D. Department of Mechanical Engineering Indian Institute of Technology Guwahati 1 EngineEngine

• Energy Conversion Device (One Form to the Other)

HeatHeat EngineEngine • Convert Thermal Energy in fuel into Mechanical Energy for motion

2 Classifying Engines

• Classification is based on: – The location of the combustion •Internal / External – The type of combustion •Intermittent / Continuous – The type of internal motion •Reciprocating •Rotational

3 Internal Combustion Engines

• Combustion occurs Inside the engine • Internal combustion directly touches the parts that must be moved in order to produce mechanical energy • Examples: Lawnmower engines, Motorcycle engines, automotive engines

4 External Combustion Engines

• Combustion occurs indirectly on the parts that must be moved • Thermal energy heats another fluid (water), turns it into steam, and the steam pushes on a piston or part Example: Steam locomotives, Boilers

5 External Combustion

6 Intermittent Combustion Engines

• Combustion within the engine STARTS and STOPS many times during operation

7 Continuous Combustion Engine

• Combustion process that continues constantly without stopping • It remains burning continuously • Examples: – Turbine engines – Rocket engines – Jet engines

8 II CC EnginesEngines

• An internal combustion engine is defined as a device in which the chemical energy of the fuel is released inside the engine and used directly for mechanical work, as opposed to an external combustion engine in which a separate combustor is used to burn the fuel.

9 History • The internal combustion Nikolaus Otto patented engine was first conceived the 4-stroke engine when he was only 34! and developed in the late 1800’s • The man who is considered the inventor of the modern IC engine is pictured to the right ...Nikolaus Otto (1832- 1891). • Otto developed a four- stroke engine in 1876, most often referred to as a Spark Ignition, since a spark is needed to ignite the fuel air mixture. 10 • Another important cycle is the Diesel cycle developed by Rudolph Diesel in 1897. This cycle is also known as a compression ignition engine.

• Almost all travel and transportation is powered by the IC engine: trains, automobiles, airplanes are just a few. 11 Reciprocating Engines

• Motion produced from within the fuel (combustion) moves parts up an down • Piston or internal parts are moved back and forth • Examples: lawn mowers, cars, trucks, etc...

12 Rotary Engines

• Has continuous rotation of the parts that are moving

• The combustion is pushing an internal part around in a circular path

Examples: Wankel engines Turbine engines

13 Forms of Kinetic Energy • Reciprocation – motion that is defined on a linear path – up-and-down; back-and-forth

• Rotation – Motion that is defined on a circular path – spinning; turning

14 Kinetic Energy within Intermittent Combustion Engines

• Piston Movement – intermittent – Reciprocating – Not useful enough

• Crank shaft – Connected to piston – turns linear motion into rotation motion

15 Thermodynamic Principles

• All internal combustion – Open cycle, heated engine

• (Otto) engine – Spark ignition – Compresses air-fuel mixture

• – Compressed ignition – Compresses air only

16 PartsParts ofof anan II CC EngineEngine

Name as many parts as you can

Your name:______

CROSS SECTION OF OVERHEAD VALVE FOUR CYCLE SI ENGINE 17 Structural Components

• Cylinder Block – Part of engine frame that contains cylinders in which piston moves – Supports liners & head

18 Structural Components

• Cylinder Head/Assembly – Serves to admit, confine, and release fuel/air – Cover to cylinder block – Supports valve train • Crankcase – Engine frame section that houses the crankshaft • Oil sump – Reservoir for collecting and holding lube oil 19 Moving Components

• Three Groups – according to motion – Reciprocating only (pistons and valves) – Reciprocation & rotary (connecting rods) – Rotary only (crankshafts and camshafts)

20 Moving Components • Piston – Acted on by combustion gases – Lightweight but strong/durable • Piston Rings – Transfer heat from piston to cylinder – Seal cylinder & distribute lube oil • Piston Pin – Pivot point connecting piston to connecting rod • Connecting Rod – Connects piston & crankshaft – reciprocating rotating motion 21 Moving Components

• Crankshaft – Combines work done by each piston – Drives camshafts, generator, pumps, etc. • – Absorbs and releases kinetic energy of piston strokes, and smoothens rotation of crankshaft

22 Moving Components

• Valves – Intake: open to admit air to cylinder (with fuel in Otto cycle) – Exhaust: open to allow gases to be rejected • Camshaft & Cams – Used to time the addition of intake and exhaust valves – Operates valves via pushrods & rocker arms

23 Cylinder head Air cleaner PartsParts ofof anan Breather cap

II CC EngineEngine Rocker arm Choke Valve spring Valve guide Throttle Pushrod

Intake manifold Sparkplug Exhaust manifold Combustion chamber Tappet Piston rings Dipstick Piston Cam Wrist pin Cylinder block Camshaft Connecting rod Water jacket Oil gallery to piston Wet liner Oil gallery to head Connecting rod bearing Crankcase Crankpin Crankshaft Main bearing

Oil pan or sump CROSS SECTION OF OVERHEAD VALVE FOUR CYCLE SI ENGINE 24 Definitions

• Stroke - the number of times the piston travels the length of the cylinder • Cycle - composed of 4 parts – Intake - working substance is introduced – Compression - working substance is compressed by upward movement of the piston – Power - ignition => forcing the piston down – Exhaust - removal of exhaust gases

25 Definitions – contd.

•• TopTop DeadDead CenterCenter -- when the piston is at its highest point in the cylinder. The volume of the working fluid is a minimum.

•• BottomBottom DeadDead CenterCenter -- when the piston is at its lowest point in the cylinder. The volume of the working fluid is a maximum.

26 Some Engine Terms •• BoreBore-- diameter of the cylinder •• EngineEngine DisplacementDisplacement-- the volume of air that is displaced by all the pistons during one upward stroke. •• CompressionCompression RatioRatio-- the comparison of the cylinder volume when the piston is at BDC and the volume when the piston is at TDC. •• EngineEngine strokestroke – A stroke is a single traverse of the cylinder by the piston (from TDC to BDC) – 1 revolution of crankshaft = 2 strokes of piston

27 EngineEngine PowerPower • IC engines can deliver power in the range from 0.01 kW to 20 x 103 kW, depending on their displacement

• Number of Cylinders may vary from 1 to 20 with different geometric configurations.

44 andand 22 StrokeStroke EnginesEngines

‰ A 4 stroke engine requires 2 full revolutions of the crankshaft to complete the cycle.

‰ While the 2 stroke only requires 1 revolution of the shaft complete the same cycle. 28 Operation

• Increased pressure of combustion gases acts on piston, and is converted to rotary motion • Can be 2 or 4 stroke engines – 2-stroke: 1 power stroke per 1 crankshaft rev – 4-stroke: 1 power stroke per 2 crankshaft rev

29 Four Stroke SI Engine

• Induction Stroke: fill cylinder with fuel and air • Compression Stroke: squeeze mixture • Power Stroke: burn and extract work • Exhaust Stroke: empty cylinder of exhaust

30 31 Induction Stroke • Engine pulls piston out of cylinder • Low pressure inside cylinder • Atmospheric pressure pushes fuel and air mixture into cylinder • Engine does work on the gases during this stroke

Compression Stroke • Engine pushes piston into cylinder • Mixture is compressed to high pressure and temperature • Engine does work on the gases during this stroke 32 Power Stroke • Mixture burns to form hot gases • Gases push piston out of cylinder • Gases expand to lower pressure and temperature • Gases do work on engine during this stroke Exhaust Stroke • Engine pushes piston into cylinder • High pressure inside cylinder • Pressure pushes burned gases out of cylinder • Engine does work on the gases during this stroke 33

• Car stores energy in an electromagnet • Energy is released as a high voltage pulse • Electric spark ignites fuel and air mixture • Two basic types of ignition – Battery – Magneto

34 Four-Stroke Diesel Engine • Intake stroke – Intake valve open, exhaust valve shut – Piston travels from TDC to BDC – Air drawn in • Compression stroke – Intake and exhaust valves shut – Piston travels from BDC to TDC – Temperature and pressure of air increase • Power stroke – Intake and exhaust valves shut – Fuel injected into cylinder and ignites – Piston forced from TDC to BDC • Exhaust stroke – Intake valve shut, exhaust valve open – Piston moves from BDC to TDC – Combustion gases expelled 35 36 SummarySummary

37 FUEL A I Ignition R

Fuel/Air Mixture Combustion Products

SS Intake Compression Power Exhaust uu Stroke Stroke Stroke Stroke mm Four Stroke Spark Ignition Engine A mm I Fuel Injector aa R

rr Air Combustion yy Products

Intake Compression Power Exhaust Stroke Stroke Stroke Stroke Four Stroke Compression Ignition Engine

38 References 1. Crouse WH, and Anglin DL, (1985), Automotive Engines, Tata McGraw Hill. 2. Eastop TD, and McConkey A, (1993), Applied Thermodynamics for Engg. Technologists, Addison Wisley. 3. Fergusan CR, and Kirkpatrick AT, (2001), Internal Combustion Engines, John Wiley & Sons. 4. Ganesan V, (2003), Internal Combustion Engines, Tata McGraw Hill. 5. Gill PW, Smith JH, and Ziurys EJ, (1959), Fundamentals of I. C. Engines, Oxford and IBH Pub Ltd. 6. Heisler H, (1999), Vehicle and Engine Technology, Arnold Publishers. 7. Heywood JB, (1989), Internal Combustion Engine Fundamentals, McGraw Hill. 8. Heywood JB, and Sher E, (1999), The Two-Stroke Cycle Engine, Taylor & Francis. 9. Joel R, (1996), Basic Engineering Thermodynamics, Addison-Wesley. 10. Mathur ML, and Sharma RP, (1994), A Course in Internal Combustion Engines, Dhanpat Rai & Sons, New Delhi. 11. Pulkrabek WW, (1997), Engineering Fundamentals of the I. C. Engine, Prentice Hall. 12. Rogers GFC, and Mayhew YR,YR (1992), Engineering Thermodynamics, Addison Wisley. 13. Srinivasan S, (2001), Automotive Engines, Tata McGraw Hill. 14. Stone R, (1992), Internal Combustion Engines, The Macmillan Press Limited, London. 15. Taylor CF, (1985), The Internal-Combustion Engine in Theory and Practice, Vol. 1 & 2, The MIT Press, Cambridge, Massachusetts. 39 Web Resources 1. http://www.mne.psu.edu/simpson/courses 2. http://me.queensu.ca/courses 3. http://www.eng.fsu.edu 4. http://www.personal.utulsa.edu 5. http://www.glenroseffa.org/ 6. http://www.howstuffworks.com 7. http://www.me.psu.edu 8. http://www.uic.edu/classes/me/ me429/lecture-air-cyc-web%5B1%5D.ppt 9. http://www.osti.gov/fcvt/HETE2004/Stable.pdf 10. http://www.rmi.org/sitepages/pid457.php 11. http://www.tpub.com/content/engine/14081/css 12. http://webpages.csus.edu 13. http://www.nebo.edu/misc/learning_resources/ ppt/6-12 14. http://netlogo.modelingcomplexity.org/Small_engines.ppt 15. http://www.ku.edu/~kunrotc/academics/180/Lesson%2008%20Diesel.ppt 16. http://navsci.berkeley.edu/NS10/PPT/ 17. http://www.career-center.org/ secondary/powerpoint/sge-parts.ppt 18. http://mcdetflw.tecom.usmc.mil 19. http://ferl.becta.org.uk/display.cfm 20. http://www.eng.fsu.edu/ME_senior_design/2002/folder14/ccd/Combustion 21. http://www.me.udel.edu 22. http://online.physics.uiuc.edu/courses/phys140 23. http://widget.ecn.purdue.edu/~yanchen/ME200/ME200-8.ppt -

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