Emission controls techniques ppt
- 1. 1
- 2. INTRODUCTION • Vehicle emissions is the emissions produced by motor vehicles. • Air pollution comes from both natural and man made sources. Though globally man made pollutants from combustion, construction, mining, agriculture and warfare are increasingly significant in the air pollution equation. • Motor vehicle emissions are one of the leading causes of air pollution. • Emissions of many air pollutants have been shown to have variety of negative effects on public health and the natural environment. 2
- 3. Emissions causing pollution & health hazards Hydrocarbons :- • A class of burned or partially burned fuel, hydrocarbons are toxins. • Hydrocarbons are a major contributor to smog, which can be a major problem in urban areas. • Prolonged exposure to hydrocarbons contributes to asthma liver disease, lung disease, and cancer. Carbon monoxide (CO) :- • A product of incomplete combustion, carbon monoxide reduces the blood's ability to carry oxygen; overexposure (carbon monoxide poisoning) may be fatal. Carbon Monoxide poisoning is a major killer. 3
- 4. Nitrogen oxides (NOx) :- • Generated when nitrogen in the air reacts with oxygen at the high temperature and pressure inside the engine. NOx is a precursor to smog and acid rain. NOx is a mixture of NO, N2O, and NO2. • NO2 is extremely reactive. It destroys resistance to respiratory infection. NOx production is increased when an engine runs at its most efficient (i.e. hottest) part of the cycle. Particulate matter :- Soot or smoke made up of particles in the micrometer size range: Particulate matter causes negative health effects, including but not limited to respiratory disease and cancer. 4
- 5. Sulfur oxide (SOx):- A general term for oxides of sulfur, which are emitted from motor vehicles burning fuel containing sulfur. Reducing the level of fuel sulfur reduces the level of Sulfur oxide emitted from the tailpipe. Volatile organic compounds (VOCs):- Organic compounds which typically have a boiling point less than or equal to 250 °C; for example chlorofluorocarbons (CFCs) and formaldehyde. Volatile organic compounds are a subsection of Hydrocarbons that are mentioned separately because of their dangers to public health. 5
- 6. Effect of pollutants on Environment:- • Acid Rain ,Acid Snow & thermal pollution. • Green House Effect . • Ozone Depletion. 6
- 7. Necessity for emissions control :- • Engine efficiency has been steadily improved with improved engine design, more precise ignition timing and electronic ignition, more precise fuel metering, and computerized engine management. • Advances in engine and vehicle technology continually reduce the toxicity of exhaust leaving the engine, but these alone have generally been proved insufficient to meet emissions goals. Therefore, technologies to detoxify the exhaust are an essential part of emissions control. 7
- 8. Emission Control Techniques :- • In order to give better engine performance the emission must be reduce to a great extend. • Like SI engine CI engines are also major source of emission. Several experiments and technologies are developed and a lot of experiments are going on to reduce emission from CI engine. • There are several different types of emission control system used on modern vehicles. 8
- 9. Air injection • One of the first-developed exhaust emission control systems is secondary air injection. • Originally, this system was used to inject air into the engine's exhaust ports to provide oxygen so unburned and partially burned hydrocarbons in the exhaust would finish burning • Air injection is now used to support the catalytic converters oxidation reaction, and to reduce emissions when an engine is started from cold. 9
- 10. Exhaust gas recirculation • In internal combustion engines, exhaust gas recirculation (EGR) is a nitrogen oxide (NOx) emissions reduction technique used in petrol/gasoline and diesel engines. EGR works by recalculating a portion of an engine's exhaust gas back to the engine cylinders. In a gasoline engine, this inert exhaust displaces the amount of combustible matter in the cylinder. 10
- 11. Catalytic converter • The catalytic converter is a device placed in the exhaust pipe, which converts hydrocarbons, carbon monoxide, and NOx into less harmful gases by using a combination of platinum, palladium and rhodium as catalysts. • Platinum and palladium are used to change HC and CO into CO2 and Water. • Rhodium acts to reduce NOx emissions • There are two types of catalytic converter, a two-way and a three- way converter. Two-way converters were common until the 1980s, when three-way converters replaced them on most automobile engines. 11
- 12. 12
- 13. Fuel Evaporative Emissions Control • Evaporative emissions are the result of gasoline vapors escaping from the vehicle's fuel system. Since 1971, all U.S. vehicles have had fully sealed fuel systems that do not vent directly to the atmosphere; mandates for systems of this type appeared contemporaneously in other jurisdictions. • In a typical system, vapors from the fuel tank and carburetor bowl vent (on carbureted vehicles) are ducted to canisters containing activated carbon. • The vapors are absorbed within the canister, and during certain engine operational modes fresh air is drawn through the canister, pulling the vapor into the engine, where it burns 13
- 14. Use Of Hybrid Vehicles • A hybrid vehicle is a vehicle that uses two or more distinct power sources to move the vehicle. The term most commonly refers to hybrid electric vehicles (HEVs), which combine an internal combustion engine and one or more electric motors. Gasoline engine Lead-Acid Batteries Generator Electric motor To car wheels Block diagam of series system of hybrid car 14
- 15. Use Of Alternate Fuels • LPG • CNG • HYDROGEN • VEGETABLE OILS • ALCOHOLS Methanol Ethanol 15
- 16. REFERENCES 1.International Journal of Automotive Technology, Vol. 14, No. 2, pp. 195−206 (2013) 2.Combustion and Emission of Combustion Engine. Jiang Deming. Xian, Xian Jiao tong University Press, 2001. 3.'"Case less monolithic catalytic converter". Charles H. Bailey. U.S. Patent 4,250,146: 10 February 1981 4."General Motors believes it has an Answer to the Automotive Air Pollution Problem". The Blade: Toledo, Ohio. 1974-09-12. Retrieved 2011-12-14. 5."Exhaust Gas Made Safe."Popular Mechanics, September 1951, p. 134. Journals & research paper Books 1. INTERNAL COMBUSTION ENGINES by-K.K. RAMALINGAM 16
- 17. 17