UNIT 3 – ENERGY AND POWER 3-6 UNIT 3 Topics Covered IOT POLY ENGINEERING 3-6 UNIT 3 – ENERGY AND POWER UNIT 3 Topics Covered Energy Sources – Fuels and Power Plants Trigonometry and Vectors Classical Mechanics: Force, Work, Energy, and Power Impacts of Current Generation and Use

Power Plants – Engines 3-6 Reciprocating Engines: IOT POLY ENGINEERING 3-6 Types of Engines Reciprocating Engines: Reciprocate: to move forward and backward alternately Pistons move linearly, forward and backward, in reciprocating engines. A crank converts linear motion into rotational motion.

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

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 http://inventors.about.com/library/inventors/blotto.htm

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 http://en.wikipedia.org/wiki/Internal_combustion_engine#Two-stroke

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 http://upload.wikimedia.org/wikipedia/commons/f/f7/Four_stroke_cycle_compression.jpg 1 8 2 9 3

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, 250 cc’s, etc. W / “3-bank” http://www.ul.ie/~kirwanp/linkstoanimations.htm http://auto.howstuffworks.com/engine2.htm http://en.wikipedia.org/wiki/W_engine Straight/inline 4 V6 Flat 4

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: http://www.ul.ie/~kirwanp/linkstoanimations.htm http://en.wikipedia.org/wiki/Camshaft

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 Enhanced with additives to tune performance and reduce emissions Enhanced with isooctane to prevent engine “knocking” http://www.eia.doe.gov/kids/energyfacts/sources/non-renewable/naturalgas.html#HOWWEGETIT “same” 8 hydrocarbon

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 $ http://www.eia.doe.gov/kids/energyfacts/sources/non-renewable/naturalgas.html#HOWWEGETIT

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 http://www.eia.doe.gov/kids/energyfacts/sources/non-renewable/naturalgas.html#HOWWEGETIT

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 http://www.eia.doe.gov/kids/energyfacts/sources/non-renewable/naturalgas.html#HOWWEGETIT