Honda Civic Hybrid, Manual

Page: 322 / 333

The exhaust emissions controls
include four systems: PGM-FI,
ignition timing control, exhaust gas
recirculation, and three way catalytic
converter. These 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.
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 ), nitrogen
(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
powertrain control module (PCM)
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.
2
2
Exhaust Emissions Controls
PGM-FI System Exhaust Gas Recirculation (EGR)
System
Three Way Catalytic Converter
Ignition Timing Control System
Emissions Controls
Technical Inf ormation
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