IOT POLY ENGINEERING Energy Sources – Fuels and Power Plants 2.Trigonometry and Vectors 3.Classical Mechanics: Force, Work, Energy, and Power 4.Impacts of Current Generation and Use U NIT 3 – E NERGY AND P OWER Topics Covered

IOT POLY ENGINEERING 3-6 Power Plants 1.The engine, motor, and related parts a.Supplies the motive power of a self-propelled object b.Produces a kinetic energy output from a fuel source input 2.Electricity generating station a.Typically what is referred to by “power plant” b.Mechanical, heat, chemical, solar sources Types of Power Plants

IOT POLY ENGINEERING 3-6 Power Plants 1.Insight into the fundamental operation of most engineered technologies 2.Application of scientific and mathematical principles in real-world problem-solving situations Why Study Power Plants?

IOT POLY ENGINEERING 3-6 Power Plants – Engines 1.Combustion – the burning of fuel with an oxidizer 2.Oxidizer – a chemical compound that transfers oxygen atoms – a typical oxidizer is ambient air 3.Ambient – surrounding, environmental, atmospheric 4.External combustion engine (ECE) – heat engine that derives heat from fuel consumed outside engine 5.Internal combustion engine (ICE) – heat engine that derives heat from combustion of fuel within engine, instead of in external furnace 6.Thermodynamics – physics that deals with the mechanical action or relations of heat Terminology

IOT POLY ENGINEERING 3-6 Power Plants – Engines Types of Engines Historically – engine referred to device that converted force into motion 1)Catapult, battering ram, and other siege weapons 2)Mills – grinding 3)Water mill, wind mill, horse mill, treadmill 4)al-Jazari – invented crankshaft and connecting rod, one of the most important mech. technologies after wheel 5)1698 – first practical steam powered engine – Thomas Savery

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

IOT POLY ENGINEERING 3-6 Power Plants – Engines 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.

IOT POLY ENGINEERING 3-6 Power Plants – Engines 1.Steam Engine a.Steam 1)Molecules of gases are further apart than molecules in liquids and solids 2)Vaporized water (steam) takes up more space than liquid water Types of Engines – E.C.E.

IOT POLY ENGINEERING 3-6 Power Plants – Engines 1.Steam Engine (continued) b.History 1)75 C.E. Hero of Alexandria – mathematician Presented plans for simple steam engine 2)1679 Denis Papin of France – pressure cooker 3)1698 Thomas Savery, English military engineer – Miner’s Friend pumped water out of coal mines 4)1712 Newcomen Engine, improved Savery’s design Types of Engines – E.C.E.

IOT POLY ENGINEERING 3-6 Power Plants – Engines 1.Steam Engine (cont.) b.History (cont.) 5)1765 James Watt (Scotland) – mathematician, inventor, instrument maker, engineer Modern steam engine credited to Watt 6)1804 Arthur Woolf (England) – compound steam engine Increases the efficiency of the engine by reusing the steam in additional cylinders. Types of Engines – E.C.E.

IOT POLY ENGINEERING 3-6 Power Plants – Engines 1.Steam Engine (cont) c.Steam Locomotive 1)1770s – tracks laid for horses to pull carts 2)1804 – steam-powered engine 3)1820s – “Father of Railways” George Stephenson – civil and mechanical engineer Builds first public railway lines d.Harnessing steam power made the Industrial Revolution possible Types of Engines – E.C.E.

IOT POLY ENGINEERING 3-6 Power Plants – Engines 1.Steam Engine (cont) d.Operation – PISTON Types of Engines – E.C.E. 1)High pressure steam enters 2)HP steam pushes piston 3)Valve rod shifts 4)HP steam pushes piston in reverse direction 5)Original steam, now cooled, exits through exhaust: Choo-choo-choo-choo-choo

IOT POLY ENGINEERING 3-6 Power Plants – Engines 1.Steam Engine (cont) d.Operation – PISTON Types of Engines – E.C.E. Steam Exhaust Coal Exhaust

IOT POLY ENGINEERING 3-6 Power Plants – Engines 1.Steam Engine (cont) d.Operation – BOILER Types of Engines – E.C.E. 1)Coal burned in furnace 2)Hot gasses boil water 3)Steam moves to cylinder, gases exhaust through smokestack Fire-tube Boiler (past) Water-tube Boiler (modern)

IOT POLY ENGINEERING 3-6 Power Plants – Engines 1.Steam Engine (cont) d.Operation – COMPOUND STEAM ENGINE 1)Engineers’ objective is to harness as much of the energy in the burning fuel as possible. 2)Compound steam engine reuses exhaust steam/fuel as much as possible (3 times below). Types of Engines – E.C.E.

IOT POLY ENGINEERING 3-6 Power Plants – Engines 1.Steam Engine (cont) Types of Engines – E.C.E. Explain what you see…

IOT POLY ENGINEERING 3-6 Power Plants – Engines 1.Steam Engine (cont) Types of Engines – E.C.E. Explain what you see…

IOT POLY ENGINEERING 3-6 Power Plants – Engines 1.Steam Engine (cont) Types of Engines – E.C.E. Explain what you see…

IOT POLY ENGINEERING 3-6 Power Plants – Engines 1.Steam Engine (cont) Types of Engines – E.C.E. Explain what you see…

IOT POLY ENGINEERING 3-6 Power Plants – Engines Types of Engines 2.Gasoline Ignition I.C.E. – four stroke Otto Engine / Otto Cycle Nicolaus Otto first to develop functioning 4-stroke engine Uses spark plugs to ignite fuel/air mixture

IOT POLY ENGINEERING 3-6 Power Plants – Engines Types of Engines 2.Gasoline Ignition I.C.E. – 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

IOT POLY ENGINEERING 3-6 Power Plants – Engines Types of Engines 2.Gasoline 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 9)Crank Case

IOT POLY ENGINEERING 3-6 Power Plants – Engines Types of Engines 3.Gasoline Ignition I.C.E. – two stroke 1)Does not have valves – simplifies construction and lowers weight 2)Fire once every revolution, instead of every other (4-stroke) – power boost 3)Work in any orientation (4- stroke limited due to oil flow)

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

IOT POLY ENGINEERING 3-6 Power Plants – Engines Types of Engines 3.Gasoline Ignition I.C.E. – two stroke 1)Notice in this animation the “return positive pressure” 2)What purpose does it fulfill? Returns unused fuel to cylinder

IOT POLY ENGINEERING 3-2 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

IOT POLY ENGINEERING 3-2 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 waste of $ Power Plants – Engines

IOT POLY ENGINEERING Engines - Cams Power Plants – Engines Cam – lobes that force open valves Camshaft – cylindrical rod that runs length of cylinder bank Explain the operation of the valves:

IOT POLY ENGINEERING Engines – Internal Combustion Engine Power Plants – Engines Identify the type of internal combustion engine: 2-Stroke I.C.E. 4-Stroke I.C.E.

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

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

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

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

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

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:

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

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

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

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

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

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