Technological Impacts

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UNIT 3
UNIT 3 ENERGY AND POWER
Topics Covered

• Energy Sources Fuels and Power Plants
• Trigonometry and Vectors
• Classical Mechanics
• Force, Work, Energy, and Power
• Impacts of Current Generation and Use

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Power Plants
Types of Power Plants

• The engine, motor, and related parts
• Supplies the motive power of a self-propelled
  object
• Produces a kinetic energy output from a fuel
  source input
• Electricity generating station
• Typically what is referred to by power plant
• Mechanical, heat, chemical, solar sources

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Power Plants
Why Study 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

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Power Plants Engines
Terminology

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

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Power Plants Engines
Types of Engines

• Historically engine referred to device that
  converted force into motion
• Catapult, battering ram, and other siege weapons
• Mills grinding
• Water mill, wind mill, horse mill, treadmill
• al-Jazari invented crankshaft and connecting
  rod, one of the most important mech. technologies
  after wheel
• 1698 first practical steam powered engine
  Thomas Savery

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Power Plants Engines
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

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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.

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Power Plants Engines
Types of Engines E.C.E.

• Steam Engine
• Steam
• Molecules of gases are further apart than
  molecules in liquids and solids
• Vaporized water (steam) takes up more space than
  liquid water

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Power Plants Engines
Types of Engines E.C.E.

• Steam Engine (continued)
• History
• 75 C.E. Hero of Alexandria mathematician
• Presented plans for simple steam engine
• 1679 Denis Papin of France pressure cooker
• 1698 Thomas Savery, English military engineer
  Miners Friend pumped water out of coal mines
• 1712 Newcomen Engine, improved Saverys design

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Power Plants Engines
Types of Engines E.C.E.

• Steam Engine (cont.)
• History (cont.)
• 1765 James Watt (Scotland) mathematician,
  inventor, instrument maker, engineer
• Modern steam engine credited to Watt
• 1804 Arthur Woolf (England) compound steam
  engine
• Increases the efficiency of the engine by
  reusing the steam in additional cylinders.

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Power Plants Engines
Types of Engines E.C.E.

• Steam Engine (cont)
• Steam Locomotive
• 1770s tracks laid for horses to pull carts
• 1804 steam-powered engine
• 1820s Father of Railways George Stephenson
  civil and mechanical engineer Builds first public
  railway lines
• Harnessing steam power made the Industrial
  Revolution possible

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Power Plants Engines
Types of Engines E.C.E.

• Steam Engine (cont)
• Operation PISTON

• High pressure steam enters
• HP steam pushes piston
• Valve rod shifts
• HP steam pushes piston in reverse direction
• Original steam, now cooled, exits through
  exhaust
• Choo-choo-choo-choo-choo

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Power Plants Engines
Types of Engines E.C.E.

• Steam Engine (cont)
• Operation PISTON

Coal Exhaust
Steam Exhaust
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Power Plants Engines
Types of Engines E.C.E.

• Steam Engine (cont)
• Operation BOILER

• Coal burned in furnace
• Hot gasses boil water
• Steam moves to cylinder, gases exhaust through
  smokestack
• Fire-tube Boiler (past)
• Water-tube Boiler (modern)

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Power Plants Engines
Types of Engines E.C.E.

• Steam Engine (cont)
• Operation COMPOUND STEAM ENGINE
• Engineers objective is to harness as much of the
  energy in the burning fuel as possible.
• Compound steam engine reuses exhaust steam/fuel
  as much as possible (3 times below).

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Power Plants Engines
Types of Engines E.C.E.

1. Steam Engine (cont)

Explain what you see
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Power Plants Engines
Types of Engines E.C.E.

1. Steam Engine (cont)

Explain what you see
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Power Plants Engines
Types of Engines E.C.E.

1. Steam Engine (cont)

Explain what you see
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Power Plants Engines
Types of Engines E.C.E.

1. Steam Engine (cont)

Explain what you see
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Power Plants Engines
Types of Engines

• 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

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Power Plants Engines
Types of Engines

• 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

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Power Plants Engines
Types of Engines
7

• Gasoline Ignition I.C.E. four stroke
• Identify the following components
• Piston
• Connecting rod
• Crankshaft
• Valves
• Spark plug
• Cams
• Cam shaft
• Cylinder
• Crank Case

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6
5
4
4
1
8
2
3
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Power Plants Engines
Types of Engines

• Gasoline Ignition I.C.E. 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 orientation (4-stroke limited due to
  oil flow)

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Power Plants Engines
Types of Engines

• Gasoline Ignition I.C.E. two stroke
• Compression/Charging
• Compression of air/fuel/oil mixture
• Fuel pulled into crankcase by vacuum charging
• Transfer/Exhaust
• Spark ignition
• Intake port exposed
• Exhaust forced out

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Power Plants Engines
Types of Engines

• Gasoline Ignition I.C.E. two stroke
• Notice in this animation the return positive
  pressure
• What purpose does it fulfill?

Returns unused fuel to cylinder
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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

hydrocarbon
same
8
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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 waste
  of

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Power Plants Engines
Engines - Cams

• Cam lobes that force open valves
• Camshaft cylindrical rod that runs length of
  cylinder bank
• Explain the operation
• of the valves

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

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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

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Power Plants Engines
Types of Engines IC

• Diesel Engine
• No spark plug
• 4-stroke engine
• Air intake
• Compression
• Fuel injection / Combustion
• Exhaust

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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 ccs, etc.

W / 3-bank
Straight/inline 4 V6 Flat 4
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Power Plants Engines
Engines Cams

• Cam lobe that forces open valves
• Camshaft cylindrical rod that runs length of
  cylinder bank
• Explain valve operation

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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

hydrocarbon
same
8
37
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

38
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

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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

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1. Oil starts in the sump/pan
2. Pump sends oil through filter
3. Oil enters galleries

1. Oil lubricates main bearings and camshaft
   bearings
2. Lubricates crankshaft and rods
3. Seals piston rings

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Power Plants Engines

• Engine Oil

Filler Cap
Oil Pan
Drain Bolt
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