HONDA 2001 Civic GX - Owner's Manual - Manual (Page 44)

Emissions Controls
The burning of compressed natural
gas in your vehicle's engine
minimizes the production of several
byproducts. Some of these are
carbon monoxide (CO), oxides of
nitrogen (NOx) and hydrocarbons
(HC). 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 Clean Air Act
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 196 in the
primary owner's manual.
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 Crank-
case Ventilation valve routes them
from the crankcase back to the
intake manifold. They are then
drawn into the engine and burned.
Technical Information
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