Making current cars more efficient
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Making current cars more efficient. Minimize the force required: ma+msg+ C r mv+C D A f v 2 /370 Make m small Make C r small Make C D small Make A f small Make v small Or any combination of reducing these values. Flex-Fuel Vehicles.

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Making current cars more efficient

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Making current cars more efficient

Making current cars more efficient

  • Minimize the force required:

    • ma+msg+ Crmv+CD Af v2 /370

  • Make m small

  • Make Cr small

  • Make CD small

  • Make Af small

  • Make v small

  • Or any combination of reducing these values


Flex fuel vehicles

Flex-Fuel Vehicles

  • Internal combustion engines designed to run on more than one fuel

  • Second fuel is usually ethanol or sometimes methanol

  • Fuel blend is detected by sensors that adjust ignition and timing to match the mixture

  • Most North American vehicles are optimized to run on mixtures up to E85.


The first flex fuel vehicle

The first Flex Fuel Vehicle

  • Any guesses?


The first flex fuel vehicle was

The first flex fuel vehicle was

  • The Ford Model T!!!!

  • Designed to run on petroleum, ethanol or kerosene

  • Prohibition made ethanol unviable and decreasing costs of petroleum made it more attractive

  • 1909-1927


Alternatives to the internal combustion engine

Alternatives to the internal combustion engine

  • Flywheels

  • Electric batteries

  • Hybrids

  • Alcohol

  • Hydrogen


Flywheels

Flywheels

  • Energy storage device

  • Flywheel is spun up and the energy is stored as rotational energy to be used at a later time

  • Designed to resist losses of rotational energy due to friction, etc

  • Energy stored is given by

    • Ek = Iω2

      where I = moment of inertial of the flywheel, and ω is the angular velocity.

  • The moment of inertial is a function of the mass and the distance from the center of rotation

  • So the structure of the flywheel and the rotational rate determine the amount of energy stored.

  • Ultimate limit on the energy storage is the strength of the flywheel. Spin it too fast, and it will tear itself apart.


  • Flywheel vehicles

    Flywheel vehicles

    • Could extract energy from braking-rather than waste the energy into frictional heating of brakepads, reverse the engine and spin up the flywheel.

    • Need to be recharged on the power gird, saves gas, but drains electricity

    • The big implementation problem is materials which can withstand the stress needed to spin the flywheel fast enough to make this a worthwhile alternative.

    • Prototype mass transportation vehicles have been built (In Sweden and by Lockheed)

    • Used in Formula 1 racing to recover energy lost in braking and along with a continuously variable transmission to improve Formula one car acceleration.

    • Also used in the incredible hulk roller coaster at Universal Islands of Adventure in Orlando, Fl.

      • Ride starts with an uphill acceleration, rather than a gravity drop.

      • Flywheels are used to provide the initial energy impulse, otherwise the park would brown out the local energy grid everytime the ride began.


    Hybrids

    Hybrids

    • Still use gasoline powered engines, but combine them with (usually) batteries to achieve better fuel economy.

    • Different from a flex-fuel vehicle:Flexible fuel vehicles (FFVs) are designed to run on gasoline or a blend of up to 85% ethanol (E85).

      • no loss in performance when operating on E85.

      • FFVs typically get about 25-30% fewer miles per gallon when fueled with E85.

    • Idea is to use as small as possible a gasoline engine, and only when it can be run at peak efficiency.

    • Use excess power to recharge the battery (no need to tap the power grid)

    • Use energy from braking (regenerative braking) to also charge the battery

    • Work best in stop and go driving.

    • Major initiative in the auto industry right now.

    • Result in using less gas-stretching our fossil fuels


    Hybrid cars

    Hybrid cars


    Hybrid models

    Hybrid Models

    • Hyunai Sonata Hybrid

    • Honda CRZ and Fit

    • Mercedes Benz ML 450

    • BMW

    • Dodge Ram

    • Chevy Silverado

    • Toyota Prius

    • Chevy Volt –WKU president drives one

      • has a total driving range of up to 379 miles. For the first 35 miles, it can drive gas free using a full charge of electricity stored in its 16-kWh lithium-ion battery. When the Volt’s battery runs low, a gasoline-powered engine seamlessly operates to extend the driving range another 244 miles on a full tank.


    Pure electric vehicles

    Pure electric vehicles

    • Powered by an electric motor, rather than a gasoline engine

    • Needs batteries – current generation of batteries have 520 times less energy density than gasoline.

    • Need to be charged from the power grid

    • If all the vehicles in the US were converted to electric cars, it would triple the current electric energy generation

    • Recharging electric vehicles takes time- several hours, whereas it takes minutes to refill your gas tank

    • Batteries have a finite lifetime, need to be replaced every 2-3 years at a current cost of 1000

    • Limited range (less than 100 miles before recharging is needed)

    • Ultimate limit is current battery technology-current lead acid batteries have not changed much in 100 years.

    • Environmental effects from the disposal of lead acid batteries

    • No new promising battery technologies on the horizon to substantially help electric cars


    Electric car engine

    Electric Car Engine


    Types of electric vehicles

    Types of electric vehicles

    • Ford Focus EV due in late 2011

    • Nissan Leaf - out now


    Fuel cells

    Fuel cells

    • An electrochemical conversion device

    • Chemical reactions cause electrons (current) to flow

    • Requires a fuel, an oxidant and an electrolyte ( a substance that contains free ions and acts as a conductor)

    • Typical type of fuel cell is called a proton exchange membrane fuel cell (PEMFC)


    Hydrogen fuel cells

    Hydrogen Fuel Cells

    • Clean-only emission is water

    • Expensive to produce

    • Highly efficient-in an automobile, efficiencies of converting fuel energy to mechanical energy of 60% could be achieved, almost double the current efficiencies

    • Hydrogen itself has issues as a fuel source


    Issues with hydrogen

    Issues with Hydrogen

    • Abundant in nature, but not a freely available fuel

    • Must be unbound from compounds

    • Currently obtained via steam reforming

      • Steam and a nickel catalyst react, producing H

      • Need steam at very high temperatures, 1600F

    • In the future, H is anticipated to be produced by the electrolysis of water, requiring large amount of water and electricity


    Electrolysis

    Electrolysis

    • Pass an electrical current through water and obtain H

    • Pass a direct current from a battery or other DC power supply through a cup of water (salt water solution increases the reaction intensity making it easier to observe).

    • Using platinum electrodes, hydrogen gas will be seen to bubble up at the cathode, and oxygen will bubble at the anode.

    • Choice of the electrode is critical, you do not want a metal that will react with oxygen


    Issues with hydrogen1

    Issues with Hydrogen

    • Storage-occurs in gas form at room temperature, hard to contain

    • As a liquid, it can be stored, but needs temperatures of -253 C.

      • As a liquid, its energy density increases 1000 times

      • In principle, could replace gasoline as a liquid fuel, but not practical at this time

    • One solution is to store it as a metallic hydride (the negative ion of Hydrogen in a compound with another element) at room T.


    Issues with h

    Issues with H

    • Highly explosive

      • Forms a volatile mixture with air

    • A mixture of 4-75% of H in air is explosive, compared with natural gas which is only explosive in a range of 5-15% concentration in air

    • Ignition energy is small, needing only 2 x 10-5 J (basically a spark of static electricity can ignite H)

    • Only good news is its low density means if there is a H leak, it disperses quickly


    Hydrogen

    Hydrogen

    • Hindenburg disaster

    • Hindenburg was a German passenger airship (zeppelins) built for transatlantic air flight.

    • Filled with Hydrogen

    • Something caused ignition of the Hydrogen-cause is debatable

    • 36 fatalities out of 79 people onboard


    Alchohol

    Alchohol

    • Use methanol or ethanol as a fuel

      • Already gone over ethanol

    • Methanol is already in use at Indy 500 race

      • Proven that no significant loss of performance is experienced (though they are in the process of switching to ethanol)

    • About ½ the energy content of gasoline

    • Produces only CO2 and water

      • Some nitrogen oxides produced in the engine

    • Can be manufactured from re-newable sources (biomass for example)

    • Technologies exist now.


    Disadvantages

    Disadvantages

    • Very dangerous

      • Burns with no visible flame-needs a colorant added

      • Fumes are toxic

    • CO2 is a greenhouse gas

    • Currently made mostly from natural gas-a non-renewable fossil fuel

    • Possibly more corrosive than ethanol to engine parts


    Use in liquid fuel cells

    Use in liquid fuel cells

    • Another use is as a input to a liquid feed fuel cell

    • In these cells, Methanol replaces hydrogen

    • Methanol has a much higher energy density and is easier to store than H

    • Current methanol fuel cells produce power too low for vehicles, but can be used in cell phones, laptops etc

    • Advantage is that they store lots of power in a small space, which they over a long period of time


    Environmental effects of energy production

    Environmental effects of energy production

    • All of our energy producing mechanisms have some effect on the environment

      • Production of waste products pollutes air, water and ground

      • Disruptions to local ecosystems

    • Our job is to understand and mitigate these effects to the best of our ability

    • Philosophy : If it hurts (the environment) when you do that, don’t do that!


    Air pollution

    Air pollution

    • If its in the air, its in your body

    • Components of the Earth’s Atmosphere:

      • Nitrogen 78.08%

      • Oxygen 20.95%

      • Argon 0.93%

      • Also small amounts of Neon, Helium, Krypton,& Hydrogen

    • In addition, there are compounds whose concentrations vary with height: water vapor, carbon dioxide, methane, carbon monoxide, ozone, ammonia

    • These are naturally occurring concentrations, any additional influx or destruction of these compounds via human beings alters the system.


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