Catalytic Converter - Volvo XC90 Owner's Manual

11 Specifications

Catalytic converter

General
The purpose of the catalytic converter is to
purify exhaust gases. It is located in the flow
of exhaust gases close to the engine so that it
quickly reaches operating temperature. The
catalytic converter consists of a monolith
(ceramic or metal) with channels. The channel 11
walls are lined with a thin layer of platinum,
rhodium and palladium. These metals act as
catalysts, i.e. they participate in and acceler-
ate a chemical reaction without being used
up themselves.
Lambda-sond TM oxygen sensor
The Lambda-sond is part of a control system
intended to reduce emissions and improve
fuel economy.
An oxygen sensor monitors the oxygen con-
tent of the exhaust gases leaving the engine.
This value is fed into an electronic system
that continuously controls the injectors. The
ratio of fuel to air directed to the engine is
continuously adjusted. Together with the
three-way catalytic converter, these adjust-
ments create optimal conditions for efficient
combustion of the harmful emissions (hydro-
carbons, carbon monoxide and nitrous
oxides).
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