Emissions controls – HONDA 2008 Accord Coupe User Manual
Page 389
The burning of gasoline in your
vehicle’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.
Controlling the production of NOx,
CO, and HC is important to the
environment. Under certain
conditions of sunlight and climate,
NOx and HC react to form
photochemical ‘‘smog.’’ Carbon
monoxide does not contribute to
smog creation, but it is a poisonous
gas.
The United States Clean Air Act
sets standards for automobile
emissions. It also requires that
automobile manufacturers explain to
owners how their emissions controls
work and what to do to maintain
them. This section summarizes how
the emissions controls work.
In Canada, Honda vehicles comply
with the Canadian emission
requirements, as specified in an
agreement with Environment
Canada, at the time they are
manufactured.
Your vehicle has a positive
crankcase ventilation system. This
keeps gasses that build up in the
engine’s crankcase from going into
the atmosphere. The positive
crankcase ventilation valve routes
them from the crankcase back to the
intake manifold. They are then
drawn into the engine and burned.
As gasoline evaporates in the fuel
tank, an evaporative emissions
control 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.
The onboard refueling vapor
recovery (ORVR) system captures
the fuel vapors during refueling. The
vapors are adsorbed in a canister
filled with activated carbon. While
driving, the fuel vapors are drawn
into the engine and burned off.
The Clean Air Act
Crankcase Emissions Control
System
Evaporative Emissions Control
System
Onboard Ref ueling Vapor
Recovery
Emissions Controls
386
2008 Accord Coupe
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