Emission Controls - Honda 1992 Civic Sedan Owner's Manual

Emission Controls

The burning of gasoline in your
car's engine produces several by-
products. Some of these are carbon
monoxide (CO), oxides of nitrogen
(NOx) and hydrocarbons (HC).
Gasoline evaporating from the tank
also produces hydrocarbons. Con-
trolling the production of NOx, CO,
and HC is important to the environ-
ment. Under certain conditions of
sunlight and climate, NOx and HC
react to form photochemical "smog."
Carbon monoxide does not contri-
bute to smog creation, but it is a
poisonous gas.
Technical Information
The Clean Air Act
The Clean Air Act* sets standards
for automobile emissions. It also
requires that automobile manufac-
turers explain to owners how their
emission controls work and what to
do to maintain them. This section
summarizes how the emission con-
trols work. Scheduled maintenance
is on page 103.
* In Canada, Honda vehicles
comply with the Canadian Motor
Vehicle Safety Standards (CMVSS)
on Emissions valid at the time they
are manufactured.
Crankcase Emission Control
System
Your car has a Positive Crankcase
Ventilation (PCV) System. This
keeps gasses that build up in the
engine's Crankcase from going into
the atmosphere. The PCV valve
routes them from the crankcase
back to the intake manifold. They
are then drawn into the engine and
burned.
Evaporative Emission
Control System
As gasoline evaporates in the fuel
tank, a canister filled with charcoal
adsorbs the vapor. It is stored in
this canister while the engine is off.
After the engine is started and
warmed up, the vapor is drawn into
the engine and burned during
driving.