Page 130 - Methods For Monitoring And Diagnosing The Efficiency Of Catalytic Converters A Patent - oriented Survey

1 12 Methods for Monitoring and Diagnosing the Efficiency of Catalytic Converters

Because the amount of oxygen stored in the converter, however, is limited (limit levels are
shown by one point chain lines in fig. 55b), misjudgment may be caused when the balance
between the oxygen absorbing power and the oxygen releasing power falls beyond the limits,
that is, between time tt and tl, between time t4 and tb and between time t7 and t9.

rich
t4 t5 /I I 1
; At9
I
I
I
a1 I lean i/ 76 ti \I
t2 t8 I
I I I
I I 1 I I I
I I I I I f
I I I I ! I
I
I
I
I
I
absbrbing I reldasing I absdrbing ~ I releasing
~ ,-
I I I I I I

Possibility of Possibility of Possibility of
misjudgemet misjudgemet misjudgemet

Fig. 55 (from EP0801215)

Other methods presented by Toyota Motor Co Ltd. are described in JP7139400 (1995),
JP8291740 (1996) and JP8291741 (1996).