there are the three major pollutant emissions for which
gasoline-powered vehicles are
controlled are: unburned hydrocarbons (HC), carbon monoxide (CO), and
nitrogen oxides (NOx). Diesel-powered
vehicles primarily emit NOx and particulates.
Motor vehicles contribute only a small percentage of total man-made
emissions of other atmospheric pollutants, such as
sulfur oxides. Evaporative HC emissions from
the fuel tank and carburetor are adsorbed by
activated carbon contained in a canister installed on the vehicle. Blow-by
HC emissions from the crankcase are controlled by
positive crankcase ventilation
(PCV). Exhaust emissions of HC, CO, and NOx — the products of incomplete
combustion — are controlled primarily by a
catalytic converter, in conjunction
with exhaust gas recirculation
and increasingly sophisticated technology for improving combustion
efficiency, including electronic emission controls.
Also see
emissions (stationary source),
hydrocarbon emissions, pollutants.
Application
Notes:
