Three-Way Catalyst (Twc) System; Oxidation Catalyst (Oc) System - Toyota 4-Runner 1985 Repair Manual

EC-46
Three-Way Catalyst (TWC) System
EMISSION CONTROL SYSTEMS (CARB.) - Oxidation Catalyst (OC) System
THREE-WAY CATALYST (TWC) SYSTEM
{Californir '
Three-Way Catalyst
(Monolithic)
A03064
EC2901
To reduce HC, CO and NOx emissions, they are oxidized, reduced and converted to nitrogen (N2), carbon dioxide (C02)
and water (H20) by the catalyst.
Exhaust Port
HC, CO and NOx
TWC
Oxidation and
reduction
Exhaust Gas
OXIDATION CATALYST (OC) SYSTEM
(Federal and Canada)
Oxidation Catalyst
EC2901
To reduce He and eo emissions, He and CO are oxidized and converted to water (H20) and carbon dioxide (C02) by
the catalyst.
Exhaust
Unburnt HC, eo and
AIR
Converter
Exhaust Gas
Oxidation