UNIT I - Pollution • Pollution is the introduction of contaminants into the natural environment that cause adverse change • Air Pollution • Water Pollution • Soil pollution
Automotive emissions have three sources: • Evaporative • Crankcase • Exhaust
Types of Emission Exhaust Emission Evaporative Emission • Pollutants in Exhaust Gas Carbon monoxide(CO) Oxides of Nitrogen(Nox) Hydro Carbons(HC) Smoke and Soot Lead Sulphuric Oxide Particulate
HC CO Solid particulate Catalytic Converter Exhaust manifold Fuel Tank Air Fuel Pump Fuel Fuel Vapors Fuel
Exhaust Gasses NOx increases HC increases Richer Leaner 14.7 – 1 AFR Hc and Co decreases NOx decreases
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.
Carbon Dioxide (CO2) Fossil fuels (coal, oil, natural gas) How Global Warming Works
Example of the Greenhouse Effect 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.
GLOBAL WARMING is the increase of the Earth’s average surface temperature due to a build-up of greenhouse gases in the atmosphere. CLIMATE CHANGE is a broader term that refers to long-term changes in climate, including average temperature and precipitation. Difference
Indian Automobile Industry • Largest three wheeler market in the world • 2nd largest two wheeler market in the world • 7th largest passenger car market in Asia & 10th Largest in the world • 4th largest tractor market in the world • 5th largest commercial vehicle market in the world • 5th largest bus & truck market in the world
There are many actions individuals can take to reduce their gas consumption. • By saving gas, these actions are good for: respiratory health, helping clean the air, fighting climate change, and saving you money! • Best of all, these actions are… S . I . M . P . L . E
SSS S peed 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.
II I dling • Avoid idling: Excessive idling pollutes. 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.
MMM M atch vehicle to need • Do you need a vehicle?: You could save yourself a lot of money and time by evaluating if you even need a vehicle. Maybe you could take the bus? Or walk to your destinations? • What do I need the car for?: This would help you find out what kind of car you need. Do you need a truck for work? Do you just need something small to get into town? Do you need a van because you have a large family?
MM M atch vehicle to need ? ? • Should I buy a used car or a new car? Older cars can be less expensive, but can also be bad for the environment and bad on fuel. New cars produce less emission and are more fuel efficient.
PP P ressure • Check tire pressure:5% of under-inflation = 1% decrease in fuel efficiency. Under-inflation of 20% will reduce the life of your tire by about 15%. *4 tires 15% under-inflated = 12% fuel waste!
L L eave your car at home • Reduce your number of trips: The best way to reduce fuel use and save money is by planning activities and combining errands to reduce the number of trips.
EE E ngine tune up • 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.
EE E ngine tune up • 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. • Clean or replace air filters and spark plugs:Clean filters and spark plugs help keep fuel use and greenhouse gas emissions down. • Have your idle mixture and idle speed adjusted:Adjusting idle speed according to vehicle specifications on pre-1988 vehicles can decrease greenhouse gas emissions during idling.
O O ther factors • 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.
O O ther factors • Travel light: The heavier the vehicle, the more fuel it burns. Avoid unnecessary weight. • 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.
O O ther factors • Have your oxygen sensor checked:Vehicles made in 1988 or after should have the oxygen sensor checked regularly. When this sensor malfunctions, the computer could increase the fuel ration to burn more fuel and thus increasing greenhouse gas emissions. • Replace or service the EGR valve: The exhaust gas recirculator (EGR) valve reduces a variety of greenhouse gases. • Use a timed block heater: Improve fuel efficiency by 8 to 23% with a block heater at below 0oC. Set timer for 2.5 hours before you leave.
UNIT II Pollution from S.I. Engine Products of Complete Products of Incomplete Combustion Combustion NOxSOxLead CO HC Parti- Lead culates
I.C. Engine & Environment COx HC NOx Lead SOx Particulates CO CO2 CH4 Others N2O NO NO2 SO2 SO3Particles Smoke Poison Aerosols Soot Poison GHG GHG Carcinogens GHG P C Smog P C Smog Visibility Acid Rain Acid Rain P C Smog OD GHG Acid Rain Visibility Irritation
S.I. ENGINE EMISSIONS EVAPORATIVE CRANKCASE EXHAUST FUEL CARB. CO, HC, NOX, PART. TANK FLOAT BOWL UBHC UBHC FOR THE S.I. ENGINE WITH CARBURETOR: EVAPORATIVE EMISSIONS ACCOUNT FOR APPROXIMATELY 20% CRANKCASE EMISSIONS ACCOUNT FOR APPROXIMATELY 20% EXHAUST EMISSIONS ACCOUNT FOR THE BALANCE 60%
The Internal Combustion Engine and Atmospheric Pollution Type of Pollution Principal Sources Relevance of the I.C. Engine Lead Anti-knock compounds A (for the SI Engine) Carcinogens Diesel exhaust A Acid Rain Sulfur dioxide B (for the CI Engine) Oxides of nitrogen A Unburned hydrocarbons A (for the SI Engine) Carbon monoxide A (for the SI Engine) Global warming CFCs B (for car with A/c) (or else not involved) Carbon dioxide B (may be even A) Methane B (may be A if CNG used) Photochemical smog Carbon monoxide A (for the SI Engine) Unburned hydrocarbons A (for the SI Engine) Sulfur dioxide B (for the CI Engine) Oxides of nitrogen A Ozone depletion CFCs B (for car with A/c) (or else not involved) Unburned hydrocarbons A (for the SI Engine) Oxides of nitrogen A A: Major contributor B: Secondary influence
UNIT III EVAPORATIVE EMISSIONS
Major Sources: • Dirunal Emissions • Take place from fuel tanks and carburetor float bowls • (in engines fitted with carburetors) of parked vehicles. • It draws in air at night as it cools down • Expels air and gasoline vapour as it heats up during the day. • These could be up to 50g per day on hot days.
Hot Soak Emissions This occurs after an engine is shut down. The residual thermal energy of the engine heats up the fuel system leading to release of fuel vapours.
Running Losses Gasoline vapours are expelled from the tank (or float bowl) when the car is driven and the fuel tank becomes hot. This can be high if the ambient temperature is high.
Filling Losses(Refueling Losses) Gasoline vapours can escape when the vehicle is being refueled in the service station.
“Evaporative emissions increase significantly if the fuel volatility increases”
Evaporative emissions are tested in the • “Sealed Housing Evaporative Determination – SHED” test procedure • evolved in the US. • Vehicle is placed in the enclosure and emissions are measured as • the temperature in the fuel tank is increased. • This gives diurnal emissions. • Running losses are determined by running the vehicle on a chassis dynamometer • with absorbent charcoal canisters attached at various possible emission sources. • The latest procedure involves running the vehicle through • 3 standard driving cycles in the SHED. • The hot soak test measures emissions for one hour immediately following • the hot soak test. • Acceptable losses from the complete procedure are 2g of fuel per test • for US, Europe and India.
Evaporative Emission Control: • Positive Crankcase Ventilation (PCV) System • (for crankcase emissions) • Charcoal Canister System • (for Fuel tank and carburetor float bowl emissions)
Exhaust Emissions: • CO • NO • HC
CO Formation • Primarily dependent on the equivalence ratio. • Levels of CO observed are lower than the maximum values • measured within the combustion chamber • but are significantly higher than equilibrium values • for the exhaust conditions • The processes which govern CO exhaust levels are • kinetically controlled • The rate of re-conversion from CO to CO2 is slower than • the rate of cooling. • This explains why CO is formed even with • stoichiometric and lean mixtures.