Energy and the Environment

1. Energy and the Environment Fall 2012 Instructor: Xiaodong Chu Email：chuxd@sdu.edu.cn Office Tel.: 81696127

2. Flashbacks of Last Lecture • Moving a vehicle along a highway requires the expenditure of mechanical power to turn the wheels • Part of this power is needed to overcome the drag force(气动阻力) exerted by the air on the moving vehicle • Another part is needed to counter the resistance of the tires moving over the ground, called the rolling resistance(滚动阻力) • If the vehicle is climbing a hill, additional power is needed to lift it vertically in the earth’sgravitational field(重力场) • When the vehicle accelerates to a higher speed, power is needed to increase the kinetic energy(动能)of the vehicle

3. Flashbacks of Last Lecture • The total power thus becomes • For a given driving cycle, heavy cars will require more powerful engines and will consume more fuel, more or less in proportion to vehicle mass, than will light vehicles • For driving at a steady speed(等速/恒速), only rolling and aerodynamic resistance must be overcome, the power required being

4. Flashbacks of Last Lecture • There are two major methods to improve vehicle fuel efficiency: improvements to the vehicle design and to the power source

5. Transportation: Electric Drive Vehicles • In the earliest years of the development of the automobile, some were powered by electric drive motors (电力驱动电机) energized by lead-acid storage batteries (铅酸蓄电池) • In the last few years, advances in energy storage systems and the energy savings to be made by storing vehicle braking power make such vehicles attractive from both the emissions and vehicle efficiency point of view

6. Locomotives Golf Carts Fork Lifts Busses Nuclear Submarines Elevators Transportation: Electric Drive Vehicles

7. Hydrogen Fuel Cell Solar Racer Hybrid MIT CityCar Full-Size Battery Electric Neighborhood Electric Transportation: Electric Drive Vehicles

8. Transportation: Electric Drive Vehicles • 1830’s • Battery electric vehicle invented by Thomas Davenport, Robert Anderson, others - using non-rechargeable batteries • Davenport’s car holds all vehicle land speed records until ~1900 • 1890’s • EV’s outsold gas cars 10 to 1, Oldsmobile and Studebaker started as EV companies • 1904 • Krieger Company builds first hybrid vehicle • 1910’s • Mass-produced Ford cars undercut hand-built EV’s Ford Electric #2 Detroit Electric

9. Battery Fuel Battery Fuel Motor/Generator Engine Motor/Generator Engine Transmission Transmission Transmission Transportation: Electric Drive Vehicles Conventional Hybrid Battery Electric

10. Transportation: Electric Drive Vehicles Well-to-Tank Tank-to-Wheels 31% 23% Generation 33% Transmission 94% Plug-to-Wheels 76% 31% 76% = 23% Refining 82% Transmission 98% Pump-to-Wheels 16% 13% 80% 80% 16% = 13%

11. Transportation: Electric Drive Vehicles • Several manufacturers currently produce passenger cars (乘用车)and pickup trucks that are battery-powered • They have limited passenger- or freight-carrying capability compared to conventional vehicles and have much smaller travel range between recharges of the onboard (车载) energy supply • These vehicles are powered by AC induction motors (交流感应电动机) drawing their power from battery banks • The traction motor (牵引电机) can regenerate a partial battery charge during periods of vehicle deceleration

12. Transportation: Electric Drive Vehicles EV electric vehicle EVSE electric vehicle supply equipment Power Protections AC Power Supply Pilot Inverter AC charging plug On board charger AC charging cable DC charging plug Motor Battery

13. Transportation: Electric Drive Vehicle

14. Transportation: Electric Drive Vehicles • The limited range of current battery-powered electric vehicles is tied to the low energy storage densities of currently available batteries

15. 340kg 2.7 kg Transportation: Electric Drive Vehicles Gas 1 Gallon Batteries 21 Li-ion batteries(Car battery size) 135 MJ of energy

16. Transportation: Electric Drive Vehicles • Limited Range • Large battery weight/size • Long Charge times • High initial cost • Battery life • Consumer acceptance • Grid Integration

17. Transportation: Electric Drive Vehicles • Hybrid vehicles are those that combine conventional power sources (SI or CI engines) with electric motors to power the vehicle • The motor/generator can store energy in a battery bank when excess power is available, during deceleration or when the power need is less than what the combustion engine can deliver, and can deliver extra power to the wheels when it is temporarily needed for acceleration or hill climbing

18. Transportation: Electric Drive Vehicles • Hybrid vehicles are more fuel efficient (for equal mass) • This substantial advantage of the hybrid over conventional design of equal mass is a composite of braking energy recovery, more efficient engine operating conditions (despite the same driving cycle), and possibly a higher peak engine efficiency

19. Transportation: Electric Drive Vehicles

20. 2009 2010 2011 2012 Tesla Model S Cadillac XTS PHEV Sport/Luxury Tesla Roadster Volvo V70 PHEV Audi A1 PHEV Fisker Karma Porsche 918 PHEV Compact Toyota Prius Wheego LiFe Mini EV Honda insight PHEV Zenn EV Think City Mitsubishi i-MiEV Smart for two Sedan/SUV GM Volt Nissan Leaf Coda EV Toyota Rav4 EV BYD e6 EV Ford Focus EV Light Trucks Smith Electric Edison Navistar eStar Ford Transit Connect Mercedes Vito E-cell Renault Kangoo Bright Auto Idea Transportation: Electric Drive Vehicles

21. Transportation: Electric Drive Vehicles Battery Electric Vehicles (BEV): 2010 Coda Automotive Sedan 2010 Mitsubishi iMiEV BEV 2010 Nissan LEAF 2010 Ford Battery Electric Van 2010 Tesla Roadster Sport EV 2010 Chevy Volt Extended Range EV 2011 Peugeot Urban EV* 2011 Renault Kangoo Z.E. 2011 Renault Fluence Z.E. 2011 Tesla Model S 2011 BYD e6 Electric Vehicle 2011 Ford Battery Electric Small Car 2011 Opel Ampera Extended Range* 2012 Fiat 500 minicar 2012 Renault City Car* 2012 Renault Urban EV* 2012 Audi e-tron 2013 Volkswagen E-Up* 2016 Tesla EV Hybrid Electric Vehicles (PHEV): 2010 Lexus HS 250h 2010 Mercedes E Class Hybrid 2010 Porsche Cayenne S Hybrid 2010 Toyota Camry Hybrid 2010 Toyota Prius Hybrid 2011 Audi A8 Hybrid (likely introduction) 2011 BMW 5-Series ActiveHybrid 2011 Honda CR-Z sport hybrid coupe 2011 Lexus CT 200h Hybrid Hatchback 2011 Peugeot Diesel Hybrid* 2011 Suzuki Kizashi Hybrid 2011 Audi Q5 Crossover Hybrid 2011 Hyundai Sonata Hybrid 2011 Infiniti M35 Hybrid 2014 Ferrari Hybrid

22. Americas Europe Asia United States Offers up to $7,500 for qualified vehicles (Chevrolet Volt, Nissan Leaf, Coda sedan, Tesla Roadster). $2.8 billion overall budget allocated. Canada Plans to have 1 in 20 vehicles driven in Ontario to be electrically powered by 2020. Quebec offers up to $8,000. MexicoMexico City signed an agreement with Nissan to deliver recharging infrastructure for EVs in 2011. BrazilPlans to develop electric vehicles and build solar-powered charging stations in near future. United Kingdom Offers £ 5,000 max or 25% of retail. Plans to have more than 1,000 electric vehicles for its fleet and 25,000 charging points by 2015 to support running of a target 100,000 electric vehicles. France Offers €5000 or 20% of retail, valid up to 2012. Offers up to 1,000 charging stations. €400 million budget allocated for incentives, technology, and infrastructure. Germany €3,000 to 5,000 for the first 100,000 vehicles. €500 million budget allocated for EV incentives, technology, and infrastructure. China Offers up to USD $8,800 in subsidies. Plans to invest USD $15 billion to help domestic automakers put 20 million fuel-efficient vehicles on China’s roads by 2020. IndiaOffers $2,200 or 20% of retail for electric vehicles, plus other smaller subsidies for electric 2-wheelers which is majority of the market. JapanEnforces periodic vehicle inspection, testing, and taxation based on engine size to drive adoption. By 2020, 1 in 5 will be an EV vehicle. ¥106 billion budget allocated. Transportation: Electric Drive Vehicles

23. Transportation: Electric Drive Vehicles • Prototypes of electric drive vehicles whose electric power is supplied by fuel cells have been under development for several decades • Such vehicles could potentially provide higher vehicle fuel efficiencies than conventional vehicles with little or no air pollutant emissions

24. Transportation: Electric Drive Vehicles • The most economical and energy efficient source of hydrogen, a synthetic fuel, is by reforming from a fossil fuel such as natural gas, oil, or coal, or from another synthetic fuel like methanol or ethanol • The reforming operation preserves at best only 80% of the parent fuel’s heating value • If hydrogen is liquified for storage on the vehicle, rather than being stored as a compressed gas in tanks, an additional energy penalty of about 30% is incurred because energy is needed to liquify hydrogen at the very low temperature of −252.8◦C • The synthetic fuel transformation penalties diminish the fuel efficiency advantage of fuel cells compared to conventional internal combustion engines in vehicles fueled by conventional hydrocarbon fuels

25. Transportation: Vehicle Emissions • By the middle of the twentieth century, vehicle exhaust emissions (废气排放/尾气排放) were recognized to be an important contributor to urban photochemical air pollution (光化学的空气污染), e.g., high level of ground ozone concentrations(臭氧浓度) • These problems are more acute in lower latitude locations, especially in developing countries where vehicle emission controls are not yet stringent • Vehicles are mobile and more numerous than stationary sources(固定污染源), and they present different problems for abatement(消减) • It is more effective to require a few vehicle manufacturers to install control equipment on millions of new vehicles rather than to require millions of vehicle owners to try to reduce their own vehicle’s emissions

26. Transportation: Vehicle Emissions • Vehicle emissions to the atmosphere are of two kinds: exhaust emissions (废气排放/尾气排放) and evaporative emissions(蒸发排放) • The first are the combustion gases (燃烧气体)emitted while the engine is running • The second are emissions of fuel vapors (燃油蒸气)from the fuel supply system and the enginewhen the engine isnot operating • The federal government regulates both of these emissions by requiring the manufacturers of new vehicles sold in the United States to provide the technology needed to limit these emissions for the useful life (使用寿命) of the vehicle and to warrant the performance of these control systems

27. Transportation: Vehicle Emissions • To certify a vehicle class for exhaust emissions, the manufacturer must test a prototype vehicle on a dynamometer (测功机) following the Federal Test Procedure (FTP) (联邦试验程序), during which exhaust gases are collected and later analyzed for pollutant content (污染物含量), • Regulated pollutants include nonmethane hydrocarbons (NMHC) (非甲烷碳氢化合物) or organic gases (NMOG) (有机气体), carbon monoxide (CO) (一氧化碳), nitrogen oxides (NOx) (氮氧化物), particulate matter (PM) (颗粒物), and formaldehyde (HCHO) (甲醛) • The mass of each pollutant collected from the exhaust during the test is reported as grams per mile • If the prototype vehicle’s exhaust emissions do not exceed the standards set for its vehicle type, vehicles of its class and model year (车型年) may then be sold by the manufacturer

28. Transportation: Vehicle Emissions • Evaporative emissions are tested for two conditions: one where the vehicle is at rest after sufficient use to have brought it to operating temperature, the other for a prolonged period of nonuse • In these tests the vehicle is enclosed in an impermeable bag (防渗袋) of known volume, and the vapor mass is subsequently determined

29. Transportation: Vehicle Emissions • In the United States, vehicle emission standards are set by the U.S. Environmental Protection Agency (环境保护局) in accordance with the provisions of federal air-quality legislation • The regulation is based upon the recognition of the ubiquity(无处不在) and mobility(流动性) of the automobile, its concentration in urban areas, its contribution to urban and regional air-quality problems, and the ability of the manufacturer, and not the owner, to ameliorate its emissions (改善排放) • In the years since the early 1970s, when regulation was first introduced, emission standards have become more stringent as the manufacturers devised better technologies

30. Transportation: Vehicle Emissions • Could you please make a survey on China vehicle exhaust emission standards and compare them with those of US?

31. Transportation: Vehicle Emissions • Vehicle exhaust pollutants (排气污染物) are the remnants (残余物) of an incomplete combustion process in the engine cylinder • The principal molecules of this type are NO, CO, and various kinds of hydrocarbon (HC) molecules, all of which can contaminate the atmosphere • The purpose of vehicle emission control technology is to reduce the amounts of these pollutants to such low values that the cumulative effects (累积效应) of vehicles will not be great enough to cause any damage to living systems, including humans

32. Transportation: Vehicle Emissions • In SI engines, the amount of each of principal pollutants is sensitive to the air/fuel ratio of the mixture inducted into the cylinder prior to ignition by the spark plug (火花塞) • The proportion of air to fuel must not be too far from the stoichiometric value for the engine to function properly and efficiently • If the mixture is fuel-rich (富燃) (more fuel than can be completely oxidized by the available oxygen), some CO will be formed and not all of the fuel’s heating value will be released • If the mixture is fuel-lean (贫燃) (excess, unused oxygen), the combustion product (燃烧产物) temperature and pressure will be less, resulting in less engine work per cycle

33. Transportation: Vehicle Emissions

34. Transportation: Vehicle Emissions • For pollutants to reach the very low levels now being required of road vehicle exhaust streams, two steps must be undertaken simultaneously • The first is to reduce as much as possible the pollutant concentrations in the exhaust gas as it leaves the engine (engine-out emissions (发动机排放)) • The second is to reduce these emissions even further by exhaust gas treatment systems (废气处理系统) located between the engine and the tailpipe (尾喷管)

35. Transportation: Vehicle Emissions • Reducing engine-out emissions • Precise control of air/fuel ratio • Low values of the three principal pollutants—HC, CO, and NO—can be maintained if the air/fuel ratio is kept close to its stoichiometric value under all operating conditions • Fuel injection (燃油喷射)permits close control (闭环控制) over fuel flow (燃油流量) to each cylinder, and it can be computer-controlled to be proportionate to the intake air flow (进气流量) • Exhaust gas recirculation (废气再循环) • At the end of the exhaust stroke, when the exhaust valve has closed and the intake valve opens to admit a fresh charge (新鲜充量) of air–fuel mixture, the residual volume of the cylinder is filled with exhaust gas, which mixes with the incoming fresh charge • Because the amount of NO formed is very sensitive to the peak temperature reached during combustion, we can reduce engine-out NO by diluting (稀释) the fresh charge with even more exhaust gas than is normally encountered by varying the exhaust and inlet valve timing or pumping exhaust gas from the exhaust system into the intake system

36. Transportation: Vehicle Emissions • Catalytic converters (催化转换器) for exhaust gas treatment • The exhaust gas pollutants—HC, CO, and NO—are not in thermochemical equilibrium with the rest of the exhaust gas • It should be possible to oxidize both HC and CO to CO2 and H2O if enough oxygen is present, and to reduce NO to N2 and O2 • To make this happen quickly enough, these molecules must attach themselves to a solid surface coated with a catalyst (涂有催化剂的固体表面), where they can react • Current oxidation–reduction (氧化—还原) catalysts utilize such catalysts as platinum (铂) and rhodium (铑) , and they must be heated to 250 ◦C or more to be effective

37. Transportation: Vehicle Emissions

38. Transportation: Vehicle Emissions • Evaporative emissions • Fuel stored in the fuel tank (油箱)emits vapor into the air space above the fuel surface within the tank, which can leak to the atmosphere during fuel refilling operations and during diurnal atmospheric temperature and pressure changes • At engine shutdown, unburned fuel remains in the engine and can subsequently leak to the atmosphere from the air intake or exhaust • Fuel vapor has a different chemical composition than does the liquid fuel • Fuel tank vapor emissions are controlled by placing a vapor absorbing filter (蒸气吸附过滤器)in the vent line (通风管) between the fuel tank air space and the atmosphere

39. Transportation: Vehicle Emissions • Fuel quality and its regulation • Fuel anti-knock lead additives (铅抗爆添加剂) and sulfur have been restricted to ensure the successful operation of exhaust gas catalytic converters • Other regulation of fuel properties have been directed at both exhaust and evaporative emissions • To achieve desirable anti-knock properties, fuel refiners (炼油厂) change the composition of the fuel, utilizing more volatile components (易挥发成份)that increase vapor pressure and thereby evaporative emissions