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 poisonousgas. The Clean Air Act
The United States Clean Air Actꭧsets
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.
ꭧIn Canada, Honda vehicles comply
with the Canadian emission
requirements, as specified in an
agreement with Environment Canada,
at the time they are manufactured.
Crankcase Emissions Control System
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. Evaporative Emissions Control System
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.
Onboard Refueling Vapor Recovery
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.
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Exhaust Emissions Controls
The exhaust emissions controls
include three systems: PGM-FI,
ignition timing control, and three
way catalytic converter. These three
systems work together to control the
engine's combustion and minimize
the amount of HC, CO, and NOx that
comes out the tailpipe. The exhaust
emissions control systems are
separate from the crankcase and
evaporative emissions control systems.PGM-FI System
The PGM-FI system uses sequential
multiport fuel injection. It has three
subsystems: air intake, engine
control, and fuel control. The
powertrain control module (PCM) in
automatic transmission vehicles or
the engine control module (ECM) in
manual transmission vehicles uses
various sensors to determine how
much air is going into the engine. It
then controls how much fuel to inject
under all operating conditions.
Ignition Timing Control System
This system constantly adjusts the
ignition timing, reducing the amount
of HC, CO, and NOx produced.
Three Way Catalytic Converter
The three way catalytic converter is
in the exhaust system. Through
chemical reactions, it converts HC,
CO, and NOx in the engine's exhaust
to carbon dioxide (CO2), nitrogen
(N 2), and water vapor. Replacement Parts
The emissions control systems are
designed and certified to work
together in reducing emissions to
levels that comply with the Clean Air
Act. To make sure the emissions
remain low, you should use only new
Honda replacement parts or their
equivalent for repairs. Using lower
quality parts may increase the
emissions from your vehicle.
The emissions control systems are
covered by warranties separate from
the rest of your vehicle. Read your
warranty manual for moreinformation.
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