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 (CO ), dinitrogen
(N ), and water vapour.
The PGM-FI System uses sequential
multiport fuel injection.
It has three subsystems: Air Intake,
Engine Control, and Fuel Control.
The Engine Control Module (ECM)/
Powertrain Control Module (PCM-
A/T only) 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.
This system constantly adjusts the
ignition timing, reducing the amount
of HC, CO, and NOx produced.
The exhaust emissions controls
includethreeorfoursystems:PGM-
FI, Ignition Timing Control, Exhaust
Gas Recirculation (on some models),
and Three Way Catalytic Converter.
These three or four 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.
The Exhaust Gas Recirculation
(EGR) system takes some of the
exhaust gas and routes it back into
the intake manifold. Adding exhaust
gas to the air/fuel mixture reduces
the amount of NOx produced when
the fuel is burned.
2
2
Exhaust Emissions Controls
PGM-FI System Three Way Catalytic Converter
Ignition Timing Control System
Exhaust Gas Recirculation (EGR)
System
Emissions Controls
Technical Information 395
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