http://physics.colorado.edu/phys3070Clicker questionClicker questionClicker question 2Clicker question 2Hybrid cars – Toyota PriusHybrid cars – Toyota PriusHybrid cars – Toyota PriusHybrid cars – Toyota PriusHybrid cars – Toyota PriusPrius engine designAdvantages of hybrid designRelative repair recordBurning HydrogenFuel cellsA hydrogen economyTraffic safety and accidentsTraffic safety and accidentsFront collisionSide collisionPublic TransportationPublic transportationJudah Levine, 3070L30 1http://physics.colorado.edu/phys3070http://physics.colorado.edu/phys3070Judah LevineJudah LevineJILA SJILA [email protected]@colorado.edu303 492303 492--7785 (27785 (2--7785)7785)M,F 11M,F 11--Noon, W 1Noon, W 1--3 pm3 pmalso by appointmentalso by appointmentJudah Levine, 3070L30 2Clicker questionClicker questionThe 55 miles/hour maximum speed limit was adopted in 1972 as a way saving of gasoline. The proposal reducedconsumption primarily because: a: tire and wheel friction increase at higher speedsb: engine losses increase at higher speedsc: air friction increases significantly at higher speedsd: car air conditioners become less efficient at higher speedse: None of the above – it was adopted to reduce accidentsJudah Levine, 3070L30 3Clicker questionClicker questionThe 55 miles/hour maximum speed limit was adopted in 1972 as a way saving of gasoline. The proposal reducedconsumption primarily because: a: tire and wheel friction increase at higher speedsb: engine losses increase at higher speedsc: air friction increases significantly at higher speedsd: car air conditioners become less efficient at higher speedse: None of the above – it was adopted to reduce accidentsJudah Levine, 3070L30 4Clicker question 2Clicker question 2On a hot day, is it better to open the windows of a car or turn on its air conditioner?a: Always open the windows – the air conditioner uses too much energyb: Always turn on the air conditioner – the open windows create air turbulence and increase air frictionc: Open the windows during city driving and turn on the air conditioner on the highwayd: Open the windows on the highway and turn on the airconditioner during city drivinge: A complicated question – no obvious answerJudah Levine, 3070L30 5Clicker question 2Clicker question 2On a hot day, is it better to open the windows of a car or turn on its air conditioner?a: Always open the windows – the air conditioner uses too much energyb: Always turn on the air conditioner – the open windows create air turbulence and increase air frictionc: Open the windows during city driving and turn on the air conditioner on the highwayd: Open the windows on the highway and turn on the airconditioner during city drivinge: A complicated question – no obvious answerJudah Levine, 3070L30 6Hybrid cars Hybrid cars ––Toyota Toyota PriusPriusQQCost in 2002: $23kCost in 2002: $23kQQComparable car: Toyota Corolla, $16kComparable car: Toyota Corolla, $16kQQTax rebate: about $4k, net price Tax rebate: about $4k, net price difference about $3kdifference about $3kJudah Levine, 3070L30 7Hybrid cars Hybrid cars ––Toyota Toyota PriusPriusQQClassified as Classified as ““UltraUltra--lowlow””emissionemission––Exempt from emissions tests in ColoradoExempt from emissions tests in ColoradoQQFree parking and HOV access in some Free parking and HOV access in some places (not here)places (not here)Judah Levine, 3070L30 8Hybrid cars Hybrid cars ––Toyota Toyota PriusPriusQQAverages about 50 miles/gallonAverages about 50 miles/gallon––Smaller penalty in city drivingSmaller penalty in city driving––200 gallons for 10k miles ($500 @ $2.50)200 gallons for 10k miles ($500 @ $2.50)QQCorolla about 30 miles/gallon Corolla about 30 miles/gallon ––333 gallons for 10k miles ($833 @ $2.50)333 gallons for 10k miles ($833 @ $2.50)QQSUV average about 18 miles/gallonSUV average about 18 miles/gallon––555 555 gallonsnforgallonsnfor10k miles ($1389 @ $2.50)10k miles ($1389 @ $2.50)Judah Levine, 3070L30 9Hybrid cars Hybrid cars ––Toyota Toyota PriusPriusQQSaves about $300 per year in gasoline Saves about $300 per year in gasoline compared to a Corolla compared to a Corolla QQPurchase was not an economic decision Purchase was not an economic decision based on gasoline savingsbased on gasoline savingsJudah Levine, 3070L30 10Hybrid cars Hybrid cars ––Toyota Toyota PriusPriusQQSaves about $300 per year in gasoline Saves about $300 per year in gasoline compared to a Corolla compared to a Corolla QQPurchase was not an economic decision Purchase was not an economic decision based on gasoline savingsbased on gasoline savingsIncrease10+% →Judah Levine, 3070L30 11PriusPriusengine designengine designelectricgasolineBattery,288 voltsBehind rearseatSpecialtransmission50kW/67HPModified 4-strokecycleReal-timefeedbackof efficiencyJudah Levine, 3070L30 12Advantages of hybrid designAdvantages of hybrid designElectric motors can have very high torqueat 0 rpm (power requirement is low)Prius can start with electric drive only.Gasoline engine can be turned off when stoppedGasoline engine started only at itsoptimum speedJudah Levine, 3070L30 13Relative repair recordRelative repair recordJudah Levine, 3070L30 14Burning HydrogenBurning HydrogenQQHow will it be produced?How will it be produced?––Electrolysis of water using atomic energyElectrolysis of water using atomic energy••Efficiency less than 100%Efficiency less than 100%––Direct solar conversion Direct solar conversion QQHow will it be stored?How will it be stored?––Compression probably not practicalCompression probably not practical––Liquefy?Liquefy?••Cooling to about 20KCooling to about 20K••CarnotCarnotefficiency of a refrigerator is not greatefficiency of a refrigerator is not greatJudah Levine, 3070L30 15Fuel cellsFuel cellsCatalyst, platinum or otherPermeable only to protonsHydrogengasElectronsProtons combine withOxygen to form waterOxygen gasJudah Levine, 3070L30 16A hydrogen economyA hydrogen economyHydrogen is a transfer or storage medium Efficiency of production mechanism is importantStorage is difficultStore as cryogenic liquid?Store as high-pressure gas?Store trapped in some compound? Fuel cell more efficient that thermal engine, butcatalysts are currently expensiveJudah Levine, 3070L30 17Traffic safety and accidentsTraffic safety and accidentsPassenger cars are considerably
View Full Document
Unlocking...