Î
ÎThe United States Clean Air Act
sets standards f or automobile
emissions. It also requires that
automobile manufacturers explain to
owners how their emissions controls
workandwhattodotomaintain
them. This section summarizes how
the emissions controls work. In Canada, Acura vehicles comply
with the Canadian Motor Vehicle
Saf ety Standards (CMVSS) f or
Emissions valid at the time they are
manuf actured.
Your vehicle has a positive
crankcase ventilation system. This
keeps gasses that build up in the
engine’s crankcase f rom going into
the atmosphere. The positive
crankcase ventilation valve routes
them from the crankcase back to the
intake manif old. They are then drawn into the engine and burned.
As gasoline evaporates in the f uel
tank, an evaporative emissions
control canister f illed with charcoal
adsorbs the vapor. It is stored in this
canister while the engine is of f . Af ter
the engine is started and warmed up,
the vapor is drawn into the engine
and burned during driving.
The onboard ref ueling vapor
recovery (ORVR) system captures
the f uel vapors during ref ueling. The
vapors are adsorbed in a canister
f illed with activated carbon. While
driving, the f uel vapors are drawn
into the engine and burned of f .
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 f rom 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 f orm photochemical ‘‘smog.’’
Carbon monoxide does not contri-
bute to smog creation, but it is a
poisonous gas.
The Clean Air Act
Crankcase Emissions Control
SystemEvaporative Emissions Control
System
Onboard Ref ueling Vapor
Recovery
Emissions Cont rols
Technical Inf ormation
623
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2009 TL
