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automotive emission and control

  2. Emission Control SOURCES OF VEHICLE EMISSONS • Engine Crankcase Blow-by Fumes (20%)– heating oil and burning of fuel that blows past piston rings and into the crankcase. • Fuel Vapour (20%) – chemicals that enter the air as fuel evaporate. • Engine Exhaust (60%)- blown out the tailpipe when engine burns a hydrocarbon based fuel.
  4. AUTOMOTIVE EMISSION: Automotive emissions have following sources: Evaporative emission: it occurs when there is escaping of fuel vapours into the atmosphere from fuel tank and fuel system. Exhaust emission: release of exhaust gases like HC,CO,NOX into the environment after combustion of fuel.
  5. Pollutants in Exhaust Gas  Carbon monoxide(CO)  Oxides of Nitrogen(Nox)  Hydro Carbons(HC)  Smoke and Soot  Lead  Sulphuric Oxide  Particulate
  6. Global Climate Change • Gas and diesel burning vehicles also contribute to global climate change. • The Earth’s atmosphere acts like a blanket, trapping some of the sun’s heat near the planet’s surface. Without this natural insulation, the average temperature on Earth would be -18°C • Vehicle emissions also contain CO2, an important Green house gas (GHG). • If the atmosphere gets too thick with GHGs, too much heat gets trapped. That can mean problems for the whole world.
  7. How Global Warming Works Fossil fuels (coal, oil, natural gas) Carbon Dioxide (CO2)
  8. The Sun’s energy passes through the car’s windshield. This energy (heat) is trapped inside the car and cannot pass back through the windshield, causing the inside of the car to warm up. Example of the Greenhouse Effect
  9. There are many actions individuals can do to reduce fuel consumption of vehicle  By saving fuel, these actions are good for:  Respiratory health  Helping clean the air  Fighting climate change Help to reduce automotive emission
  10. Speed limit  Reduce your driving speed: The best fuel economy for most vehicles is 90 km/h. Reducing your speed from 100 km/h to 90 km/h improves fuel economy by 10% and from 120 km/h to 90 km/h can save 23% on fuel consumption. Avoid aggressive driving: Aggressive driving, rapid acceleration, or quick stops has been shown to increase fuel use by about 39%, and saves about 4% of your time.
  11. IDLING Avoid idling: • Excessive idling pollution • Turn off the engine whenever you can. • If you are stopped for more than ten seconds, turn it off • . In the winter, the most effective way to warm up a cold vehicle is to drive it. Idle for 30 seconds and then drive away for optimum performance and fuel efficiency.
  12. Regular tune-ups: A poorly tuned engine can consume an average of 10% more fuel. One poorly tuned vehicle can emit pollutants equivalent to 20 properly tuned vehicles. Engine tune up
  13. Engine tune up Clean or replace air filters and spark plugs: Clean filters and spark plugs help keep fuel use and greenhouse gas emissions down.
  14. Maintain braking systems: Dragging brakes can decrease fuel efficiency by up to 40%. Minimize air conditioner use: Using air conditioning can increase fuel consumption and greenhouse gas emissions by up to 21%. Maintain wheel alignment: Make sure wheels are aligned and balanced, and ball joints or constant velocity joints are lubricated. Other factors
  15.  Use overdrive and high gears: While driving, strive for the lowest engine rpm at a given road speed by selecting the highest gear in which the vehicle will operate properly. Operate overdrive automatic transmissions in the overdrive mode. Be aerodynamic: Reducing wind resistance on the highway by rolling up the windows cuts fuel consumption. Travel light: The heavier the vehicle, the more fuel it burns. Avoid unnecessary weight. Other factors
  16. Emission Control Exhaust Emissions are produced by cars, buses, and motorcycles. Four basic types of exhaust emissions: 1.Hydrocarbons (HC) 2.Carbon monoxides (CO) 3.Oxides of nitrogen (NOx) 4.Particulates.
  17. Emission Control Hydrocarbons (HC) • Resulting from the release of unburned fuel into the atmosphere. ● Produced by incomplete combustion or by fuel evaporation. • Effect could be eye, throat, and lung irritation, and, possibly cancer. Carbon Monoxide (CO) • Extremely toxic emission resulting from the release of partially burned fuel (incomplete combustion of petroleum-based fuel). • CO prevents human blood cells from carrying oxygen to body tissue. • Symptoms are headaches, nausea, blurred vision, and fatigue. • A rich air-fuel would increase CO; lean air-fuel mixture would lower CO emissions. • Mostly related to ignition problems.
  18. EXHAUST EMISSIONS The important exhaust emissions from a gasoline engine are:  Carbon monoxide  Unburnt hydroxide  Nitrogen oxide  Particulates
  19. Exhaust Gases HC(HYDROCARBON) : Produced by unburnt fuel. CAUSES OF HC: 1.Rich air fuel mixture:  Defective O2 sensor  Leaky fuel injector  Clogged air filter. 2.Very lean air fuel mixture:  Clogged fuel pump , fuel filter and fuel injector 3.Defective or worn ignition components:  Ignition coil  Spark plug wires.  Timing off
  20. Exhaust Gases Oxides of Nitrogen (NOx) ● Produced by extremely high temperatures during combustion.Cooling system issues. Lean air fuel mixture. Poor catalytic convertor. Over advanced timing. • An engine with high compression ratio, lean air-fuel mixture, and high-temperature thermostat will produce high combustion heat, resulting in formation of NOx.
  21. Exhaust Gases CO: Carbon monoxide emission are exhaust emission that is the result of partially burned fuel or products of incomplete combustion. A high carbon monoxide emission can be caused by :  Restricted or dirty air cleaner. Advance ignition timing. Clogged fuel injectors. Rich air fuel mixture. Defective or worn out ignition components.
  22. Exhaust Gases 14.7 – 1 AFRRicher Leaner HC increases NOx decreases NOx increases Hc and Co decreases
  24. Method to reduce exhaust emission Catalytic converter  Exhaust gas pass from exhaust manifold to catalytic convertor through pipe.  Due to partial combustion , gases entering inside catalytic converter consists of CO,HC,NOX.  Inside calalytic converter consists of ceramic blocks of platinum and rhodium acting as catalyst.
  25. REACTIONS:  Gas enters inside catalyst causes the oxides of nitrogen to reform into nitrogen and oxide.  NOX O2 + N2 Carbon monoxide reacts with oxygen molecules to form CO2. 2CO+O2 2CO2 The unburnt hydrocarbons react with oxygen and carbon dioxide. HC+ O2 H2O+CO2 FINALLY THE EXHAUST GASES CONSISTING OF LESS HARMFUL GASES .
  26. Catalytic Converter
  27. Emission Control System • At idle, high manifold vacuum pulls the plunger for minimum vapour flow (prevents a lean air- fuel mixture). • During acceleration, intake manifold decreases. This allows the PCV valve to move to a center position for maximum flow. • With engine off, a spring pushes the valve against its seat, closing the valve. A backfire will also close the valve. PCV (Positive Crankcase Ventilation System)
  28. Vehicle Emission Control System PCV (Positive Crankcase Ventilation System) • Uses engine vacuum to draw blow-by gases into the intake manifold for reburning in the combustion chamber. • Vacuum or electronic controlled, mounted on the valve cover.
  29. Vehicle Emission Control System Air Injection System • Forces fresh air into the exhaust ports or catalytic converter to reduce HC/CO. • Oxygen from the air injection system causes the unburned fuel to burn in the exhaust system or the catalytic converter.

Editor's Notes

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  3. <number> .REDUCE YOUR DRIVING SPEED - as you increase speed beyond 90 km/h, the increase in your fuel consumption goes up faster than your increase in speed. That is, travelling at 100km/h uses more gas that travelling at 90km/h; but, you use much more gas to go 110km/h instead of 100km/h, even though it is still only 10km/hr faster .AVOID AGGRESSIVE DRIVING - basically by taking-off and stopping quickly, you will use a lot more gas, and actually save very little time
  4. <number> AVOID IDLING - Many people idle because of an old wives tale that says it takes 3 or 5 minutes worth of gas to start a car, so you might as well leave it sunning for short stops. However, it actually only takes about 10 seconds of gas, so unless you are in traffic, your better off to turn your car off. Excessive idling is also bad for your engine. Also, avoid drive throughs! Park you car and walk in. Five minutes of idling at a drive though uses enough gas to fill a coffee cup!
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