Pollutants exhausts from Automobiles

Pollutants exhausts from automobiles

Automobiles used in our country are
a) Two wheelers and three wheelers, powered by two stroke petrol engines.
b) Passenger cars, powered by four stroke petrol engines.
c) Trucks and buses, powered by four stroke diesel engines.


The extent of pollution by these automobiles depends upon the enzine design, fuel consumption, operating condition. The emission from petrol engines are classified as follows:

A. Exhaust emissions
Theses are mostly comprised of CO, NOX, particulars containing lead compounds and unburned hydrocarbons. We can control the emission by the following ways
i. Modification of engine design
ii. Modification of operating conditions
iii. Treatment of exhaust gases.
iv. Modification of alternation of fuels.

B. Crank case emissions
It mostly contains hydrocarbons. The quality of blow depends on engine design, operating condition. This emission can be constituted by the following ways
i. By installing positive crank case ventilation system.

C. Evaporation emissions


It is estimated that an average evaporation emission of hydrocarbons from a passenger car is about 20 kg per year. Various methods to control evaporation emission are given below:
a. Stone the fuel vapour in crank case.
b. Modifying fuel by replacing C4 and C5 by corresponding paraffinic hydrocarbons.
c. Introducing suitable mechanical device.