System Purpose - Toyota 4-Runner 1985 Repair Manual

EC-16
EMISSION CONTROL SYSTEMS (CARB.) - System Purpose
System
Positive crankcase ventilation
Fuel evaporative emission control
Mixture control *
1
Dash pot*2
Exhaust gas recirculation
Air suction and fuel system
feedback control
Air suction
Three-way catalyst
Oxidation catalyst
High altitude compensation
Auxiliary system:
Automatic hot air intake
Automatic choke
Choke breaker
Choke opener
Auxiliary acceleration pump
Deceleration fuel cut
Idle advance
Cold mixture heater
Remarks:
*
1
MIT vehicles only
AIT vehicles only
Abbre-
viation
PCV
EVAP
MC
DP
EGR
-
AS
TWC
OC
HAC
HAl
-
CB
-
AAP
-
-
CMH
SYSTEM PURPOSE
Purpose
Federal
&
Canada
Reduces blow-by gas (HC)
•
Reduces evaporative HC
•
Reduces HC & CO
•
Reduces HC and CO
•
performance at idle
Reduces NOx
•
Maintains air-fuel ratio for TWC
-
and reduces HC, CO and NOx
Reduces HC & CO
•
Reduces HC, CO & NOx
-
Reduces HC & CO
•
Insures air-fuel mixture at high altitude
•
(OPT) *3
Improves driveability -cold
•
Improves driveability -cold
•
Improves driveability-cold
•
Improves driveability - hot
•
Improves driveability -cold
•
Prevents overheating OC or TWC, and
•
after burning
Improves fuel economy at idle
•
Improves driveability-cold
•
Option in USA only, except in California.
A03034
California
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-
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