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

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

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

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

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

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

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

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

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

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

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

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

13. Power Plants – Engines 3-6 Gasoline
IOT POLY ENGINEERING
3-6
Power Plants – Engines
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

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

15. Power Plants – Engines 3-6 Engine Oil Lubricates moving parts
IOT POLY ENGINEERING
3-6
Power Plants – Engines
Engine Oil
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
Cleans and inhibits corrosion – metallic parts and sludge carried out of engine to oil filter

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

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

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