Page 31 - Methods For Monitoring And Diagnosing The Efficiency Of Catalytic Converters A Patent - oriented Survey

Introduction 13

three-way catalytic converter becomes insufficient when the air-&el ratio is lean (see e.g.
EP0627548 (1 994)).

1 one-way catalytic converter
secondary air
.. /
:e,
+'
I

3

catalytic converter

b) two-way catalytic converter
reduction catalytic oxidation catalytic
converter converter
+
.I,

secondary air

c) three-way catalytic converter

control

airlfuel 7 tuning
three-way catalytic
converter
Na, HC, CO

Fig. 6 (from [8], p. LXVII)