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Transcript of Automobiles
-Energy source for Hydro-electric cars
Hydrogen Fuel Cells vs. The Common Battery
Closed vs. open system
2H2 + O2 --> 2H2O + Energy
What do you mean "membrane"?
Obtaining H2 Gas
-Burn Natural Gas, Methane
CH4[g] + 2 O2[g] → CO2[g] + 2 H2O[l] + 891 kJ
2H2O + Energy --> 2H2 + O2
-Cyanobacteria, green algae, and diatoms
What is biodiesel?
Alternative fuel comprised of mono-alkyl esters of long chain fatty acids
made of renewable resources
also referred to as methyl ester
How can Biodiesel be used?
Biodiesel can be used with the addition of petroleum or without
It DOES NOT contain petroleum on its own.
When fuel is 20% biodiesel it is B20
When fuel is pure biodiesel it is called B100
How is Biodiesel made?
the process is called transesterification
Oil (vegetable or animal) is heated above 131 degrees F
Separates Biodiesel from glycerin
How can biodiesel be used cont.
Biodiesel can be used in cans with diesel engines without any modifications to the engine
Diesel Cars from the ninties might need a biodiesel converter
Burns due to the heat of compression
Examples of Biodiesel Sources!
Pros and Cons
o Vegetable and animal oils are readily available
o Decrease in reliance on foreign oil
o Reduce carbon emissions
o Decrease in gas bill, can even grow own biodiesel sources
o Non-toxic and biodegradable
o Lubricant so can decrease engine wear
o Yellow greases from certain biodiesels can clog filters in the engine
o It can be expensive to grow the biodiesel sources
o Biodiesel has solvent properties which can cause rubber to deteriorate over time
o Can increase nitrogen oxide emissions
what would a fuel that contains 30% biodiesel be called?
What are the four strokes of the Otto Cycle?
What type of bacteria release hydrogen gas during photosynthesis?
Which type of battery is most promising for the future of electric cars?
Environmental Science for AP (AP Environmental Textbook from NHS)
Intake, compression, combustion, exhaust
Lithium ion batteries
Internal Combustion Engines
Basic Engine Parts
Crude oil is separated by boiling point
Aliphatic hydrocarbons with 7 to 11 carbons in each chain (C7H16 to C11H24)
Ex: 2C8H18 + 25O2 ==> 16CO2 + 18H2O
Problems: carbon monoxide, nitrogen oxides, and unburned hydrocarbons, amount of carbon released into atmosphere
Four stroke combustion cycle named for Nikolaus Otto who invented it in 1867
Piston starts at top and moves down to let cylinder fill with gasoline and air
Only a small drop of gasoline is necessary
Piston moves back up to compress the mixture of gasoline and air
This makes the explosion more powerful
Compression ratio is the amount of the compression (typically 8:1) and determines the octane rating of the gas that it best for the car
Octane rating shows how much gasoline can be compressed before spontaneously igniting
87 octane gasoline is 87% octane and 13% heptane
Knocking: when the gasoline is ignited by compression instead of by the spark plug. It’s bad for the engine
The spark plug releases a spark to ignite the gas when the piston is at the top of its stroke
The explosion from the reaction drives the piston down
The exhaust valve opens and the exhaust leaves the cylinder and goes to the tailpipe when the piston reaches the bottom of its stroke
Provides spark to ignite the mix of gas and air
Spark must be timed right
Intake valve lets in air and gasoline
Exhaust valve lets out exhaust
Both are closed during compression and combustion
Cylindrical piece of metal that moves up and down
Provide a sliding seal between outer edge of piston and inner edge of cylinder
Prevent fuel, air, and exhaust from escaping into sump during compression and combustion
Keep oil in sump from leaking into combustion area so its not burned and lost
Connects piston to crankshaft
Rotates at both ends so its angle can change as the piston moves and the crankshaft rotates
Turns piston’s up-and-down motion into circular motion
Electric Car Batteries:
Lithium Ion Batteries:
Main power source through combo of electric motor, its controller, and batteries
Pulses power to maintain desired speed
Pulses DC voltage from batteries, but must reverse polarity 60 times/ second.
Six sets of transistors used.
One or more electrochemical cells divided into parts called electrodes
Negative electrode, abundance of electrons. Positive electrode, deficit
3 Types of Rechargeable Batteries Suitable for Electric Cars:
Nickel Metal Hydride
Thin sheets pressed together submerged in organic solvent which acts as an electrolyte
Positive electrode- Lithium cobalt oxide
Negative electrode- carbon
Separator- microperforated plastic