Emission Controls - Honda 1990 Accord Sedan Owner's Manual

Sources of Emissions
The combustion process produces carbon monoxide, oxides of
nitrogen and hydrocarbons. The evaporation of fuel in the fuel
tank also produces hydrocarbons. Control of oxides of
nitrogen and hydrocarbons is very important since, under cer-
tain conditions, when subjected to sunlight, they react to form
photochemical smog. Carbon monoxide does not react to form
smog, but it is toxic.
Honda Motor Co., Ltd. has developed a number of systems
which are highly effective in reducing carbon monoxide, ox-
ides of nitrogen and hydrocarbons.
The Clean Air Act
The Clean Air Act requires all vehicle manufacturers to explain
in writing, the operation and maintenance of their emission
control systems.
Maintenance instructions are included on pages
operation of each system is explained on the following.
Replacement Parts
The emission control systems on your new Honda were
designed, built and certified to conform with the Federal
regulations implementing the Clean Air Act. Honda recom-
mends only the use of new, genuine Honda parts or their
equivalent. The use of other replacement parts which are not
of equivalent quality may impair the effectiveness of your car's
emission control systems.
Crankcase Emission Control System
To prevent crankcase emissions, your car is equipped with a
Positive Crankcase Ventilation (PCV) System which routes
blowby gases from the crankcase, through the PCV valve and
intake manifold, into the combustion chamber.
Evaporative Emission Control System
The Evaporative Emission Control System is designed to pre-
vent fuel vapors from escaping into the atmosphere.
Fuel vapors from the fuel tank are directed into the charcoal
canister where they are adsorbed and stored while the engine
is stopped or idling. When the coolant temperature rises to a
certain value, the vapors are drawn into the engine through the
throttle body and the intake manifold during normal engine
operation.

Emission Controls

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