Page 251 - Honda Civic

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Main Menu Table of Contents
Emissions Controls

Exhaust Emissions Controls then controls how much fuel to inject Replacement Parts
The exhaust emissions controls under all operating conditions. The emissions control systems are
include four systems: PGM-FI, designed and certified to work to-
ignition timing control, exhaust gas Ignition Timing Control System gether in reducing emissions to
recirculation, and three way catalytic This system constantly adjusts the levels that comply with the Clean Air
converter. These four systems work ignition timing, reducing the amount Act. To make sure the emissions
together to control the engine’s of HC, CO, and NOx produced. remain low, you should use only new
combustion and minimize the Honda replacement parts or their
amount of HC, CO, and NOx that Exhaust Gas Recirculation (EGR) equivalent for repairs. Using lower
comes out the tailpipe. The exhaust System qualityparts mayincreasethe
emissions control systems are The exhaust gas recirculation (EGR) emissions from your vehicle.
separate from the crankcase and system takes some of the exhaust
evaporative emissions control gas and routes it back into the intake The emissions control systems are
systems. manifold. Adding exhaust gas to the covered by warranties separate from
air/fuel mixture reduces the amount the rest of your vehicle. Read your
PGM-FI System of NOx produced when the fuel is warranty manual for more informa-
The PGM-FI system uses sequential burned. tion.
multiport fuel injection. It has three
subsystems: air intake, engine Three Way Catalytic Converter
control, and fuel control. The The three way catalytic converter is
powertrain control module (PCM) in in the exhaust system. Through
automatic transmission vehicles or chemical reactions, it converts HC,
the engine control module (ECM) in CO, and NOx in the engine’s exhaust
manual transmission vehicles uses to carbon dioxide (CO ), nitrogen
2
various sensors to determine how (N ), and water vapor.
2
much air is going into the engine. It
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