
11 Engine emission control
11.1 PETROL ENGINE POLLUTANTS
The nature and sources of pollutants
In reviewing the modern requirements of the motor
vehicle petrol engine (Section 1.1), it was mentioned
that since the late 1960s (beginning in America) in-
creasingly stringent legislation has been applied to limit
the levels of atmospheric pollutants emitted from it. It
may be recalled that the basic pollutants were identified
as being carbon monoxide, hydrocarbons and nitrogen
oxides, all of which can pose a health hazard.
Carbon monoxide (CO) is a product of incomplete
combustion which is difficult to disperse in air and can
aggravate respirator ...