Page 250 - Honda Civic

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Emissions Controls

The burning of gasoline in your The Clean Air Act intake manifold. They are then
vehicle’s engine produces several by- The United States Clean Air Act ˎ drawn into the engine and burned.
products. Some of these are carbon sets standards for automobile
monoxide (CO), oxides of nitrogen emissions. It also requires that Evaporative Emissions Control
(NOx), and hydrocarbons (HC). automobile manufacturers explain to System
Gasoline evaporating from the tank owners how their emissions controls As gasoline evaporates in the fuel
also produces hydrocarbons. Con- work andwhat todotomaintain tank, an evaporative emissions
trolling the production of NOx, CO, them. This section summarizes how control canister filled with charcoal
and HC is important to the environ- the emissions controls work. adsorbs the vapor. It is stored in this
ment. Under certain conditions of canister while the engine is off. After
sunlight and climate, NOx and HC ˎ In Canada, Honda vehicles comply the engine is started and warmed up,
react to form photochemical ‘‘smog.’’ with the Canadian emission the vapor is drawn into the engine
Carbon monoxide does not contri- requirements, as specified in an and burned during driving.
bute to smog creation, but it is a agreement with Environment
poisonous gas. Canada, at the time they are Onboard Refueling Vapor
manufactured. Recovery
The onboard refueling vapor
Crankcase Emissions Control recovery (ORVR) system captures
System the fuel vapors during refueling. The
Your vehicle has a positive vapors are adsorbed in a canister
crankcase ventilation system. This filled with activated carbon. While
keeps gasses that build up in the driving, the fuel vapors are drawn Technical Information
engine’s crankcase from going into into the engine and burned off.
the atmosphere. The positive
crankcase ventilation valve routes
them from the crankcase back to the

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