Automobile Emissions

Automobile Emissions:

The rise in civilization is closely related to improvements in transportation. In the development of transport the internal combustion engines, both petrol and diesel engines, occupy a very important position. The petrol and diesel engines, occupy a very important position. The petrol engine has provided reliable small power units for personalized transport and in this way revolutionized the living habits of people to a great extent. The diesel engine has provided the power units for transportation system, i.e. buses, and goods transportation system, i.e., trucks. Indeed the petrol engine powered automobile and diesel engine powered buses and trucks are the symbols of our modern technological society.

However, in recent times the internal combustion engine powered vehicles have come under heavy attack due to various problems created by them. The most serious of these problems is air pollution. Air pollution can be defined as addition to our atmosphere of any material which will have a deleterious effect on life upon our planet.

The engine emissions can be classified into two categories:
• Exhaust emissions and
• Non-exhaust emissions

The major exhaust emissions are
• Unburnt hydrocarbons, (HC)
• Oxides of carbon, (CO & CO2)                                                           1

• Oxides of Nitrogen, (NO & NO2)
• Oxides of sulphur, (SO2 & SO3)
• Particulates
• Soot and smoke

The first four are common to both SI and CI engines and the last two are mainly from CI engines.

The main non-exhaust emissions are:
• Unburnt hydrocarbons from fuel tank
• Unburnt hydrocarbons from the crankcase blow by.

HYDROCARBON EMISSIONS
Exhaust gases leaving the combustion chamber of an SI engine contain up to 6000 ppm of hydrocarbon components, the equivalent of 1-1.5% of the fuel. About 40% of these constitute the unburnt components of the fuel. The other 60% consists of partially reacted components that were not...