Mobile Sources

1. Mobile Sources Reading: Chap 15 • Types of mobile sources • Impact of mobile sources • Emission standards • Types of engines: gasoline vs diesel, 4-strokes vs 2-strokes • Emission Control: technology & policy • Add-on Control Device – catalytic converter • Hybrid Vehicles and Fuel Cells Aerosol & Particulate Research Laboratory

2. Ship track resulting from stack emission Types of mobile sources • Gasoline Automobiles • Diesel Trucks/Buses • Aircraft • Monitor • Number • Distance to receptors • Non-steady: cold-start emission, idling, stop & go • Others? http://earthobservatory.nasa.gov Impact of Mobile sources vs Stationary sources Aerosol & Particulate Research Lab

3. Emission Standards Historical Light-Duty Vehicle Emission Standards CAA 1977 CAAA 1990 CAAA *The test procedures between 1968 and 1972 were different enough from the current procedures that the standards are not comparable. NMHC: Non-Methane Hydrocarbons – containing only C and H. THC: Total Hydrocarbons http://www.epa.gov/greenvehicles/detailedchart.pdf Aerosol & Particulate Research Lab

4. Current Light-Duty Vehicle Emission Standards Bin: A set of emission standards within the Tier 2 program. Manufacturers must certify that each vehicle will not exceed the pollution limits for eth selected bin. Manufactures may choose from the range of bins, as long as all vehicles they sell each model year fall below a certain average emission limit. NMOG: Non-Methane Organic compounds HCHO: formaldehyde Aerosol & Particulate Research Lab

5. CA and NE states Current Light-Duty Vehicle Emission Standards TLEV: Transitional low emission vehicle LEV: Low emission vehicle ULEV: Ultra Low Emission Vehicle SULEV: Super Ultra Low Emission Vehicle PZEV: Partial Zero Emission Vehicle; PZEVs have the same standards as SULEV II, but manufactures must guarantee that the PZEVs meet the standards for a longer vehicle lifetime – 15 yrs/150K miles, plus a fully-sealed zero-emission fuel system ZEO: Zero Emission Vehicle Q: Gasoline vehicles for ULEV and ZEV? Aerosol & Particulate Research Lab

6. Heavy Duty Vehicles • For the same power output, only 70% mass compared to gasoline engines • Less volatile, Lower CO2 emission • Lower operating cost, 2/3 of an equivalent gasoline truck VMT: Vehicle Miles Traveled Lloyd and Cackette, JAWMA, 51, 2001, p809-847. Aerosol & Particulate Research Lab

7. Heavy Duty Vehicles (cont.) • Contains S (500 ppmw): new regulation kicked in 2006 • Lower operating speed, slower thrust/acceleration • Lean exhaust: catalytic converters don’t work • Also standards for PM, smoke opacity • Account for 5% of vehicles, account for 35% visibility reduction; Off-road vehicles emit 2 times PM (regulated in CA from 1996) • Soot from diesel engines is the 2nd largest contributor to global warming • Relative health risk of diesel exhaust exposure ~ 1.4 Emission regulations for diesel engines? Aerosol & Particulate Research Lab

8. Heavy-Duty Truck and Bus Engine Emission Standards EPA 1998 Standards CA Standards EPA Standards for MY 2004 Unit: gram per brake horsepower-hour (g/bhp-hr) Aerosol & Particulate Research Lab

9. Motorcycles • Small number in US (0.6% of HC, 0.1% NOx and <0.1% of PM of all mobile sources); large in developing countries • Higher emissions per mile than a car or even a SUV Thailand Tutu Highway Motorcycle Exhaust Emission Standards http://www.epa.gov/otaq/roadbike.htm Aerosol & Particulate Research Lab

10. 4-Stroke Internal Combustion Animation: http://www.allstar.fiu.edu/aerojava/pic6-3.htm Premixed gasoline vapor Combustion occurs every two revolutions Aerosol & Particulate Research Lab

11. C C C Octane Rating • A measure of gasoline’s resistance to engine knock (rattling or pinging sound in cylinders due to premature burning) • Heptane: 0 • Iso-octane: 100 • Anti-knock agents: Tetraethyl lead (Pb(C2H5)4), highly branched alkanes, aromatics • (R+M)/2: Research Octane Number (RON): test engine running at 600 rpm; Motor Octane Number (MON): test engine at 900 rpm http://en.wikipedia.org/wiki/Image:09-03-06-Octane.jpg What if a lower grade than required is used? Does my car perform better if I use a higher grade than required? Why is octane rating lower at higher altitudes? Aerosol & Particulate Research Lab

12. 2-Stroke Engine Compression stroke Power stroke http://media-2.web.britannica.com/eb-media/10/310-004-58E43DBF.gif Why two strokes are not good? Aerosol & Particulate Research Lab

13. Liquid diesel injection 700 – 900 oC from compression Ignition delay Diffusion flame Aerosol & Particulate Research Lab

14. Emission Control • Engine design, vehicle shape • Fuel composition • Octane rating, oxygenated fuel • Fuel desulfurization • Alternative fuel • natural gas, liquefied petroleum gas, methanol, ethanol , bio-diesel, hydrogen • Transportation control • Regulatory steps, public transportation, economic incentive • Regulation: Inspection • Add-on control • Alternative power generation • Solar, Electrical, Fuel Cell, Hybrid Aerosol & Particulate Research Lab

15. Vehicle Shape http://en.wikipedia.org/wiki/Drag_coefficient Asif Faiz et al., 1996, Air Pollution from Motor Vehicles Aerosol & Particulate Research Lab

16. Tire Friction • Proper tire inflation • Tire rolling resistance: 20% of energy to move the vehicle (4% of world wide CO2 emission) • Lower rolling resistance for better fuel economy • Safety concern: wet-road grip • Noise • “Green tires” based on silica reduced rolling resistance 30% compared to carbon-black based conventional tires. • Solid rubber tire: 30 kg/ton  pneumatic tires: 25 kg/ton  Tire cord construction: 20 kg/ton  radial tires (carbon based): 15 kg/ton Aerosol & Particulate Research Lab

17. Oxygenated Fuel & Fuel Desulfurization • Oxygenated fuel: mainly ethanol, (MTBE) • Oxygen content in the fuel improves oxidation and results in less CO • Fuel Desulfurization • S poisons catalyst in catalytic converter • SO2 emission • Gasoline sulfur: 80 ppm per gallon cap in US (delays in Rocky Mountain area); 30 ppm for CA; 10 ppm for EU • Diesel sulfur: 15 ppm Is oxygenated fuel requirement for summer or winter? Aerosol & Particulate Research Lab

18. Alternative Fuel • Natural Gas (mainly CH4 ; Octane rating 120) & Liquefied Petroleum Gas (LPG; C3H8 and C4H10; Octane rating 105) • Similar energy density per unit mass (not volume) to gasoline but requires compression or refrigeration to maintain them in the liquid phase • 50% less CO and VOCs • No photochemically active VOCs and no air toxics such as benzene • Issues: onboard fuel storage; handling and refueling • Methanol (CH3OH; Octane rating 112) • Low photochemical activity; relative inexpensive • Lower energy density per unit mass (40% of gasoline): shorter driving distance and more frequent refueling • Handling: dissolve rubber; toxic http://en.wikipedia.org/wiki/Liquefied_petroleum_gas Aerosol & Particulate Research Lab

19. www.mnsu.edu/news/read.php?id=old-1149701286 Ethanol as an Alternative Fuel • E85 • blend of 85% ethanol and 15% gasoline • Requires flexible-fuel vehicles (9.3 million on the road in 2010; same price as regular vehicle) • 2644 stations as of Jan/2011 (tax credit for retrofit) • Lower blending in winter (E70 when < 0 oC) • M85 • Blend of 85% methanol and 15% gasoline • Flex-fuel engines are capable of burning any proportion of the resulting blend in the combustion chamber as fuel injection and spark timing are adjusted automatically according to the actual blend detected by electronic sensors Aerosol & Particulate Research Lab

20. E85 What’s driving E85 into the market? Does it improve air quality? • Production • Mainly made from corn in US (current capacity accounts for 3% gasoline consumption) • Federal subsidy • Research on biomass conversion: cellulosic technology • Mainly from sugar cane in Brazil Drawbacks? Aerosol & Particulate Research Lab

21. Bio-diesel • Non-petroleum-based diesel fuel consisting of short chain alkyl (methyl or ethyl) esters, made by transesterification of vegetable oil or animal fat (tallow), which can be used (alone, or blended) in unmodifieddiesel-engine vehicles • Transeterification: separate the fatty acids from the glycerol by replacing the glycerol (an ester) with short linear alcohols; typically requires liquid catalyst *Evolved from a 1950 Colgate patent for producing glycerine for making explosives Aerosol & Particulate Research Lab

22. Bio-diesel • Distinguished from the straight vegetable oil (SVO) used (alone, or blended) as fuels in some converted diesel vehicles • Advantages: reduction in greenhouse gases; no sulfur; better lubricity • Disadvantages: slightly lower energy density; may contain water; cloud point (gelling) higher the petroleum diesel; by-product glycerol; more expensive • Emissions (B20): • Algae as a feedstock http://en.wikipedia.org/wiki/Biodiesel Aerosol & Particulate Research Lab

23. Traffic Congestion • In 2010, $100.9 billion drain on US economy, including • 1.9 billion gallons of fuel • 4.8 billion lost hours Data provided by Texas Transportation Institute, http://mobility.tamu.edu/ums/ Aerosol & Particulate Research Lab

24. Catalytic Converter (Gasoline) Pt, Pd Two-way In 2011, 8.6 million oz for auto catalyst, compared to 3.0 million oz for jewelry and 4.1 million oz for industrial use Based on US Patent 2742437 by E. Houdry in 1956 Bloomfield, L., Scientific America, 2001 Aerosol & Particulate Research Lab

25. Pt, Rd Three-way Aerosol & Particulate Research Lab

26. Trade-off Work in rich environment; temperature sensitive Aerosol & Particulate Research Lab

27. Cold-start emission more serious? How to control it? Older model Why some people want to “remove” catalytic converters from vehicles? Newer Model (1980’s in US) O2 for lean environment O2 & temperature O2 storage by CeO2 helps handle insufficient O2 supply Aerosol & Particulate Research Lab

28. Clean School Diesel Bus Technology Options http://www.epa.gov/cleanschoolbus/technology.htm Aerosol & Particulate Research Lab

29. Diesel Emission Control • Diesel PM Filter: Block Flow Filter http://www.epa.gov/nonroad-diesel/2004fr/pmfilters.htm http://www.epa.gov/cleanschoolbus/images/pmfilter.jpg Lean NO catalyst: Zeolite catalyst to reduce NO Combined with lean-burn engine http://www.sino-filter.cn/admin/upfile/2009530203359.jpg Aerosol & Particulate Research Lab

30. Electric Car • First electric car in 1835 by Professor Sibrandus Stratingh of Groningen, Netherlands • First battery powered electric car in 1881 by Camille Faure in France • Lost market to ICE circa 1910 • Government backed promotion (tax credit) revived electric car Thomas Edison and an electric car in 1913 (National Museum of American History) Who killed the electric car (EV1)? http://www.pbs.org/now/shows/223/ Is it really zero emission? Why isn’t it commonly used? Plug-In: uses a wall socket at night to charge and relies on an electric motor to go many miles before sipping any gasoline – good for short-distance driving in cities Where do you find a wall socket when not at home? Aerosol & Particulate Research Lab

31. Electric Car 2011 Nissan Leaf • First 5-door family car • Li ion battery: 100 miles on a single charge • Charging dock (220 V): 8 hr. 80% recharge in 30 min Cheaper to run per mile than gasoline 2010 Tesla Roadster http://money.cnn.com/2010/11/09/autos/electric_car_benefits/index.htm • First (2008) highway capable sedan in constant production • Li ion battery: 245 miles on a single charge • Charging dock (220 v): 3.5 hrs. 80% repaid recharge in 30 min tesla‑electric‑car.jpg Aerosol & Particulate Research Lab

32. Hybrid Electric Vehicle • Use 2 sources of motive energy: combustion of gasoline (Internal Combustion Engine) & electrical energy (Electric Motor energized by a Battery) • ICE for highway driving • EM provides added power during hill climbs, acceleration, and other periods of high demand • Regenerative Braking: converts some of the kinetic energy into electric energy; electric motor becomes a generator for battery • Also available for heavy-duty hybrid vehicles (diesel-electric) http://gm-volt.com Automobile.Honda.com http://1st-in-hybrid.com/.../07/volvo-hybrid-truck.jpg http://www.nrel.gov/vehiclesandfuels/ahhps/ Aerosol & Particulate Research Lab

33. Advantages of Hybrid Electrics • high performance • long-range capacities • high fuel efficiency • Fuel economy • Lower emissions Is hybrid popular? Cost: federal and state purchase incentives Driving privileges Aerosol & Particulate Research Lab

34. Fuel Cell Operation http://en.wikipedia.org/wiki/Fuel_cell http://www1.eere.energy.gov/hydrogenandfuelcells/ Aerosol & Particulate Research Lab

35. University of Florida Fuel Cell Research Lab H2 source: • H2 (gas, liquid, solid hydride) • Converted from other energy sources (coal, solar, wind) • Methanol (CH3OH) • Gasoline • Limitation of H2 fuel • Pipelines needed to convey hydrogen fuel not currently in place • Retail fueling facilities must be placed throughout Where? • Danger of H2 explosion (although gasoline explosion is also dangerous) • Requires construction of hydrogen production facilities Aerosol & Particulate Research Lab

36. Hydrogen Fueling Station Washington, DC (1st in US); 77 stations in 26 states as of May 11; 16 planned; 19 decommissioned; 2 stations in FL; Worldwide 427 BP-Praxair H2 Station www.hydrogenassociation.org/.../bpStation.jpg Honda solar-powered water electrolyzing H2 station H2 fuel station in Iceland http://www.cnn.com/2007/TECH/science/09/18/driving.iceland/index.html http://green.autoblog.com Aerosol & Particulate Research Lab

37. Methanol as an Alternative to Hydrogen • Some production facilities already exist • Distribution facilities can accommodate with slight modifications • Dispensing facilities can accommodate with only slight modifications • Currently there is an abundance of methanol Steam Reforming Equilibrium Reaction at 1atm and 300oC: CH3OH + 1.5H2O  2.896H2 + 0.896CO2 + 0.104CO + 0.603H2O Catalyzed by Phosphoric Acid Membrane (PAM) Are fuel cells used in stationary sources? Aerosol & Particulate Research Lab

38. Evaporative Loss – Refrigerant • CFC (Chlorofluorocarbons) – Ozone depleting chemical phased out starting from 1987 Montreal Protocol • Replacement: HCFCs (Hydrochlorofluorocarbons) HFCs (Hydrofluorocarbons) Impact of stockpile and CFC in discarded units? • Further ban on global warming gases • EU: HFC-134a banned in new cars in 2011; any other fluorinated gas with a GWP > 150 in all vehicles in 2017 • US: HCFCs in new appliances restricted from 2010 • Replacement: nontoxic and nonflammable • CO2 (requires new systems); DP-1 (GWP-40); Fluid H (GWP-10) http://pubs.acs.org/isubscribe/journals/cen/83/i18/html/8318gov2.html?emFrom=emLogin http://www.epa.gov/ozone/ods.html Aerosol & Particulate Research Lab

39. Quick Reflection The stone age did not end because the world ran out of stones. The oil age won't end because the world runs out of oil. - Shiek Yamani Aerosol & Particulate Research Lab