Page 288 - Methods For Monitoring And Diagnosing The Efficiency Of Catalytic Converters A Patent - oriented Survey

270 Methods for Monitoring and Diagnosing the Eficiency of Catalytic Converters

The temperature is measured by means of thermistors that are designed to sense the
temperature along the entire length of the converter

I I I I I I

800 1

750 I I I Conversion Efficiency 100%
I
I
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I
0 20 40 60
1lOOl
- I I I I b> I
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Y
Conversion Efficiency 60%

750 I I I I I
0 20 40 60
Converter Bed Length x (mm)

Fig. 1 19 (from W09420738)

The method can be better explained by means of fig. 1 19. Fig. 1 19a illustrates the variation of
temperature along the length of a catalytic converter at different times following the step
perturbation of step 2 for a converter operating at 100% efficiency, whereas fig. 119b shows
the corresponding curves for a converter operating at 60% efficiency. For an efficient