HONDA 2004 S2000 - Owner's Manual - Manual (Page 189)

The exhaust emissions controls
include four systems: PGM-FI,
Ignition Timing Control, Secondary
Air Injection System, 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 PGM-FI System uses sequential
multiport fuel injection.
It has three subsystems: Air Intake,
Engine Control, and Fuel Control.
The Engine Control Module (ECM)
uses various sensors to determine
how much air is going into the
engine. It then controls how much
fuel to inject under all operating con-
ditions.
During engine warm-up, air is
pumped into the exhaust to reduce
emissions when the engine is cold.
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 vapor.
The emissions control systems are
designed and certified to work to-
gether 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 more informa-
tion.
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.
This system constantly adjusts the
ignition timing, reducing the amount
of HC, CO, and NOx produced.
2
2
Emissions Controls
Technical Inf ormation
Exhaust Emissions Controls
Onboard Ref ueling Vapor
Recovery
Replacement Parts
PGM-FI System
Secondary Air Injection System
Three Way Catalytic Converter
Ignition Timing Control System
186
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