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IOT POLY ENGINEERING 3-6 Power Plants – Engines Types of Engines and Uses 1.External Combustion (EC) Engines: Steam – steam locomotives; turbines in electricity.

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Presentation on theme: "IOT POLY ENGINEERING 3-6 Power Plants – Engines Types of Engines and Uses 1.External Combustion (EC) Engines: Steam – steam locomotives; turbines in electricity."— Presentation transcript:

1 IOT POLY ENGINEERING 3-6 Power Plants – Engines Types of Engines and Uses 1.External Combustion (EC) Engines: Steam – steam locomotives; turbines in electricity stations 2.Internal Combustion (IC) Engines: 1)Four-stroke: cars, trucks, motorcycles, construction machinery, airplanes 2)Two-stroke: moped, dirt bike, chainsaw, trimmer, motor boat, lawnmowers, go-karts 3)Diesel: 50% new cars in europe, submarines, ships, locomotives, large trucks/machinery 3.Gas Turbine Engines: Power plants and airplanes

2 IOT POLY ENGINEERING 3-6 Power Plants – Engines 2.Spark Ignition – FOUR STROKE Otto Engine / Otto Cycle a.Nicolaus Otto first to develop functioning 4-stroke engine – 1877 b.Uses spark plugs to ignite fuel/air mixture Types of Engines – IC

3 IOT POLY ENGINEERING 3-6 Power Plants – Engines 2.Spark Ignition – FOUR STROKE Cycle begins at Top Dead Center (TDC) 1.Intake – fuel and air enter cylinder 2.Compression – fuel mixture under pressure 3.Combustion – causes expansion against piston 4.Exhaust – cooled combustion products exhausted Cylinders fire once every other revolution Types of Engines – IC

4 IOT POLY ENGINEERING 3-6 Power Plants – Engines 2.Spark Ignition I.C.E. – FOUR STROKE Identify the following components: 1)Piston 2)Connecting rod 3)Crankshaft 4)Valves 5)Spark plug 6)Cams 7)Cam shaft 8)Cylinder Block 9)Crank Case 10)Oil Galleries Types of Engines – IC

5 IOT POLY ENGINEERING 3-6 Power Plants – Engines 3.Spark Ignition – TWO STROKE a.Does not have valves – simplifies construction and lowers weight b.Fire once every revolution, instead of every other (4-stroke) – power boost c.Work in any physical orientation (4-stroke limited due to oil flow) Types of Engines – IC

6 IOT POLY ENGINEERING 3-6 Power Plants – Engines 3.Spark Ignition – TWO STROKE 1)Expansion/Transfer/Exhaust a.Spark ignition b.Intake port exposed c.Exhaust forced out 2)Compression/Charging a.Compression of air/fuel/oil mixture b.Fuel pulled into crankcase by vacuum – “charging” Types of Engines – IC

7 IOT POLY ENGINEERING 3-6 Power Plants – Engines 3.Spark Ignition – TWO STROKE a.Can you identify the strokes? b.Notice in this animation the “return positive pressure” c.What purpose does it fulfill? Returns unused fuel to cylinder, and charges cylinder Types of Engines – IC

8 IOT POLY ENGINEERING 3-6 Power Plants – Engines Types of Engines – IC 4.Diesel Ignition Compression Ignition – not spark ignition a.Spark ignition – 1)Piston compresses air/fuel mixture, spark ignites combustion. 2)Amount of pressure is limited (early combustion bad) b.Compression ignition – 1)Piston compresses air (fuel is not mixed) 2)Fuel injected into hot compressed air – initiates combustion

9 IOT POLY ENGINEERING 3-6 Power Plants – Engines 4.Diesel Ignition (cont.) d.Early gasoline engines very inefficient e.Greater power and efficiency available at higher pressures f.Rudolf Diesel – patented engine by 1892 Student of Polytechnic High School of Germany g.Fuel has higher energy density than gasoline h.Fuel emits fewer greenhouse gases i.Fuel emits greater N-gases and soot Types of Engines – IC

10 IOT POLY ENGINEERING 3-6 Power Plants – Engines 4.Diesel Engine a.No spark plug b.4-stroke engine 1)Air intake 2)Compression 3)Fuel injection / Combustion 4)Exhaust Types of Engines – IC

11 Engines – Cylinders Power Plants – Engines 1.Typically, the larger the number of cylinders, the more powerful the engine. 2.Engine power is determined by volumetric displacement a.The combined volume of all cylinders b.Example: 5 Liters, 308 Cubic Inches, 250 cc’s, etc. W / “3-bank” Straight/inline 4V6 Flat 4

12 IOT POLY ENGINEERING Engines – Cams Power Plants – Engines Cam – lobe that forces open valves Camshaft – cylindrical rod that runs length of cylinder bank Explain valve operation:

13 IOT POLY ENGINEERING 3-6 Gasoline Petroleum-derived liquid mixture, primarily fuel in internal combustion engines (not external combustion or gas turbine engines) Enhanced with additives to tune performance and reduce emissions Enhanced with isooctane to prevent engine “knocking” “same” 8 hydrocarbon Power Plants – Engines

14 IOT POLY ENGINEERING 3-6 Gasoline – Octane Rating 1.Engine Knocking – when combustion occurs in the cylinder at the wrong time 2.Not due to spark plug igniting incorrectly 3.Due to pressure exploding fuel before plug ignites 4.Octane Rating – the higher the rating, the less knocking 5.High performance cars operate at higher pressures – require higher octane. 6.Standard performance cars – higher octane is a waste of $ Power Plants – Engines

15 IOT POLY ENGINEERING 3-6 Engine Oil 1.Lubricates moving parts Creates separating film between surfaces Minimizes direct contact between parts Decreases friction, wear, excess heat Prevents the waste of useful power and the degradation of the engine, and increases efficiency 2.Cleans and inhibits corrosion – metallic parts and sludge carried out of engine to oil filter Power Plants – Engines

16 IOT POLY ENGINEERING 3-6 Engine Oil 3.Improves sealing – keeps fuel and combustion in the right place 4.Cools the engine – carries heat away from moving parts 5.Oil Galleries: Small passages in cylinder block Allow oil to flow to moving parts Power Plants – Engines

17 1.Oil starts in the sump/pan 2.Pump sends oil through filter 3.Oil enters galleries 4.Oil lubricates main bearings and camshaft bearings 5.Lubricates crankshaft and rods 6.Seals piston rings

18 IOT POLY ENGINEERING 3-6 Engine Oil Power Plants – Engines Filler Cap Oil Pan Drain Bolt Images:


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