Automobile Emissions Control
Abstract - The Automobile emissions control focus on the different types of technologies that have been introducing from early 1960’s to reduce the air pollution. They describe the different control methods involved in all the devices employed for the purpose of controlling pollution. This paper entails the information of impact of using these control techniques and devices. The detrimental effects of pollutants from automobile emissions on environment and on human beings are also covered.
Automobile emissions control covers all the technologies that are employed to reduce the air pollution-causing emissions produced by automobiles. Emission control systems have been incorporated into automobiles to prevent pollution by limiting the amount of partially burned and evaporated gases into the atmosphere. These systems have been efficient in reducing the pollution caused by automobiles to a large extent.Exhaust emissions control systems were first required on 1966 model year vehicles produced for sale in the state of California, followed by the United States as a whole in model year 1968. Their use became widespread in the following decades and now they are ubiquitous in industrialized nations and common in most others [pic]
Emissions controls have been highly successful in reducing the emissions produced by motor vehicles in terms of quantity per distance traveled. However, substantial increases in the distance traveled by each vehicle, and equally substantial increases in the number of vehicles in use, have meant that the overall reduction in pollution has been much slower.
The emissions produced by a vehicle fall into three basic categories.
A. Exhaust emissions.
B. Evaporative emissions.
C. Life cycle emissions
A. Exhaust Emissions
These are the most common form of vehicular air pollution emissions. These are the emissions which are emitted from the engine exhaust manifold. [pic]
The major pollutants emitted include:
1) Hydrocarbons: This class is made up of unburned or partially burned fuel, and is a major contributor to urban smog, as well as being toxic. They can cause liver damage and even cancer. 2) Nitrogen Oxides: These are generated when in nitrogen the air reacts with oxygen under the high temperature and pressure conditions inside the engine. Nox emissions contribute to both smog and acid rain. 3) Carbon Monoxide: A product of incomplete combustion, carbon monoxide reduces the blood's ability to carry oxygen and is dangerous to people with heart disease. 4) Carbon Dioxide: Emissions of carbon dioxide are an increasing concern as its role in global warming as a greenhouse gas has become more apparent. B. Evaporative Emissions
These are produced from the evaporation of fuel, and are a large contributor to urban smog, since these heavier molecules stay closer to ground level.
1) Gas Tank Venting: The heating of the vehicle as the temperature rises from the night-time temperature to the hottest temperatures of the day mean that gasoline in the tank evaporates, increasing the pressure inside the tank above atmospheric pressure. This pressure must be relieved, and before emissions control it was simply vented into the atmosphere. 2) Running Losses: The escape of gasoline vapors from the hot engine. 3) Refueling Emissions: These can cause a lot of hydrocarbon vapor emission. The empty space inside a vehicle's tank is filled with hydrocarbon gases, and as the tank is filled, these gases are forced out into the atmosphere. In addition, there is loss from further evaporation and fuel spillage.
C. Life Cycle Emissions
These are produced in activities associated with the manufacturing, maintenance, and disposal of the automobile. They include
• Manufacturing plant power requirements.
• Volatile solvents utilized in the manufacturing...
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