Acura 2008 MDX - Owner's Manual - Manual (Page 464)

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. 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.
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.
Scheduled maintenance is on page
.
In Canada, Acura 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.
390
The Clean Air Act
Crankcase Emissions Control
System
Evaporative Emissions Control
System
Onboard Refueling Vapor
Recovery
Emissions Controls
460
2008 MDX
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