EGEE 102 – Energy Conservation And Environmental Protection

Transportation

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Automobiles in the US (1994)

• 156 Million Vehicles• 11,400 miles average miles/y• 578 gallons of gasoline• 19.8 mpg• 88.3 billion gal of gasoline• 1.2 billion gal of Diesel

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How Cars Work?

• Almost all cars currently use what is called a four-stroke combustion cycle to convert gasoline into motion. The four-stroke approach is also known as the Otto cycle, in honor of Nikolaus Otto, who invented it in 1867. The four strokes are

• The intake stroke. • The compression stroke. • The combustion stroke • The exhaust stroke

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Best website for information

http://www.howstuffworks.com/engine.htm

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SI Engine Operation

                        

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Parts of an Engine

• Cylinder• Spark Plug• Valves• Piston• Piston Rings• Cooling system• Crankshaft

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Cylinder ArrangementV-6 Engine

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Cylinder Arrangement Inline Arrangement

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Cylinder Arrangement Flat Cylinder

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The Camshaft

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Engine Cooling System

                               

                       

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Compression Ratio

The difference between the maximum and minimum is called the displacement and is measured in liters or CCs (Cubic Centimeters, where 1,000 cubic centimeters equals a liter). So if you have a 4-cylinder engine and each cylinder displaces half a liter, then the entire engine is a "2.0 liter engine." If each cylinder displaces half a liter and there are six cylinders arranged in a V configuration, you have a "3.0 liter V-6."

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Efficiency

• When the United States recognized the hazards of its dependency on foreign oil supplies in the aftermath of the first oil embargo in 1973, passenger automobile fuel economy averaged only 14 miles per gallon (mpg).

• Congress established Corporate Average Fuel Economy (CAFE) standards in 1975 for each automaker, with domestically produced and imported automobiles counted as separate fleets.The uniform CAFE standard for automobiles began at 18 mpg with the 1978 model year, increasing to 27.5 mpg by 1985

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Energy Intensity of Passenger Transport

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Energy Intensity of Freight Transport (Btu/ton-miles)

Source: http://www.eia.doe.gov/emeu/efficiency/eefig_ch5.htm#Figure%205.5

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Efficiency of a IC Engne

• As the compression ratio increases efficiency increases

• As the compression ratio increases, fuel quality (Octane number) is important

• Higher compression ratios produce more power, up to a point. The more you compress the air/fuel mixture, however, the more likely it is to spontaneously burst into flame (before the spark plug ignites it). Higher octane gasoline prevents this sort of early combustion

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Gasoline: Octane Number

1. Octane has an octane rating of 1002. Heptane has an octane rating of 0

Gasoline is compared in a test engine with a mixture of heptane and “octane.”

The higher the “octane” number the less likely to knock.

For More info: http://www.howstuffworks.com/question90.htm

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Octane Number

Higher octane numbers are obtained by adding:

1. Branched chain hydrocarbons

2. Aromatics (now being reduced)

3. Antiknock agents

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Tubocharger

                                     

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Where the turbocharger is located in the car

• Power is determined by the amount of air and fuel that it can burn.

• The typical boost provided by a turbocharger is 6 to 8 pounds per square inch (PSI).

• Increased restriction in the exhaust

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Cars and Environment

• See hand out

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Automobile Emissions

• Hydrocarbons (Paraffins, Olefins, Naphthenes, Aromatics)

• Nitrogen Oxides (NO, NOx, NO2) • Carbon Dioxide (CO2) • Carbon Monoxide (CO) • Particulates (any material collected

on a filtering medium after exhaust dilution)

• Air Toxics (???)

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Average Passenger Car Emissions

Pollutant Emission Rate (g/mile)

Hydrocarbons 2.8

Carbon Monoxide

20.9

Nitrogen Oxides 1.39

CO2 0.916 lb

Gasoline 0.0465 gal

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Personal Auto Emissions

• Calculate the annual emissions (lbs) by your car based on the average annual mileage and the kind of car you you (mpg)?

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Effect of Carpooling

• Average commute is 20 miles round trip.

• 1,000 people participate in the carpool program.

• Calculate the personal monetary savings annually and the reduction of emissions (lbs) based on the emissions per mile

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Sources of Emissions

Pollutant %Source

CO HC NOx Particles

Exhaust 100 62 100 90

Crankcaseemission

20 10

Fuel TankEvaporation

9

Carburetorevaporation

9

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Processes by Which Gasoline Compounds Escape Burning

• Gasoline vapor-air mixture compressed into the combustion chamber crevice volumes

• Gasoline compounds absorbed in oil layers on the cylinder liner

• Gasoline absorbed by, and/or contained within, deposits on the cylinder head and piston crown.

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Parameters that Influence Emissions from Gasoline Engines

• Carburetion and Fuel Injection• Spark timing• Surface to volume ratio, valve

timing and the use of exhaust gas recirculation

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Environmental Problems

• The pollution comes from two sources. The first is the combustion of the oil. The oil makes all two-stroke engines smoky to some extent, and a badly worn two-stroke engine can emit huge clouds of oily smoke.

• Each time a new charge of air/fuel is loaded into the combustion chamber, part of it leaks out through the exhaust port. That's why you see a sheen of oil around any two-stroke boat motor.

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Catalytic Converters

                               

                       

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Pollution Reduction

• A three-way catalytic converter - Both types consist of a ceramic structure coated with a metal catalyst, usually platinum, rhodium and/or palladium. two separate catalysts.

                                     

                 

                     

                                     

                 

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Honeycomb Structure

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Catalyst Function

• The reduction catalyst is the first stage of the catalytic converter. It uses platinum and rhodium to help reduce the NOx emissions.

• The oxidation catalyst is the second stage of the catalytic converter. It reduces the unburned hydrocarbons and carbon monoxide by burning (oxidizing) them over a platinum and palladium catalyst.

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What You Can do to Save the Environment

• See the Handout (Your Car and Clean Air)

• Avoid Unnecessary Driving • Maintain your car properly• Drive your car wisely

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How to Help an Engine Produce More Power

• Increase displacement• Increase the compression ratio• Stuff more into each cylinder• Cool the incoming air• Let air come in more easily• Let exhaust exit more easily• Make everything lighter • Inject the fuel

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Hybrid Technology Efficiency

• Recover energy and store it in the battery

• Sometimes shut off the engine

• Use advanced aerodynamics to reduce drag

• Use low-rolling resistance tires

• Use lightweight materials

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Hybrid Cars Available

Honda Insight

Toyota Prius

http://www.eren.doe.gov/EE/transportation.html

http://www.honda2001.com/insight/homepage.html

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HEVs

• The HEV is able to operate approximately two times more efficiently than conventional vehicles. Honda's Insight can go 700 miles on a single tank of gas. The Toyota Prius can go about 500 miles. For the driver, hybrids offer similar or better performance than conventional vehicles. More important, because such performance is available now, hybrids are a practical way for consumers to chose a cleaner drive today.

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Cars of the Future

• Hybrid cars• combines two or

more sources of power.

• Fuel Cells

                  

         

http://www.eren.doe.gov/EE/transportation.html

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Fuel Cells

• Based on an electrochemical reaction that combines hydrogen with ambient air

• Pure hydrogen or any fossil fuel that has been "reformed" can be used to produce a hydrogen-rich gas

• Fuel cell's emission is mostly water vapor• Energy conversion efficiencies up to 50%

are demonstrated• ..\..\..\Desktop\Ami_320x240.ram

http://www.ott.doe.gov/pdfs/fuelcell_basics.pdf

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Alternative Fuels

• Methanol• Ethanol• CNG• Oxygenated Fuels• Reformulated Fuels

More information on Clean Fuels:http://www.epa.gov/otaq/consumer/06-clean.pdf

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Two Stroke Engines

• Lawn and garden equipment (chain saws, leaf blowers, trimmers)

• Dirt bikes

• Mopeds

• Jet skis

• Small outboard motors

• Radio-controlled model planes

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2 Stroke Engine

• Two-stroke engines do not have valves, which simplifies their construction.

• Two-stroke engines fire once every revolution (four-stroke engines fire once every other revolution) -- this gives two-stroke engines a significant power boost.

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Two Strokes

                         

                             

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Disadvantages of Two Stroke Engines

• Two-stroke engines don't last nearly as long as four-stroke engines. The lack of a dedicated lubrication system means that the parts of a two-stroke engine wear a lot faster.

• Two-stroke oil is expensive, and you need about 4 ounces of it per gallon of gas. You would burn about a gallon of oil every 1,000 miles if you used a two-stroke engine in a car.

• Two-stroke engines do not use fuel efficiently, so you would get fewer miles per gallon.

• Two-stroke engines produce a lot of pollution. So much, in fact, that it is likely that you won't see them around too much longer.