Page 258 - Methods For Monitoring And Diagnosing The Efficiency Of Catalytic Converters A Patent - oriented Survey

240 Methods for Monitoring and Diagnosing the Efficiency of Catalytic Converters

apparatus is preferred. This electronic monitoring apparatus can ascertain a temperature
distribution in the catalytic converter and/or a mean value and/or a maximum value from the
measured temperature values and can carry it over a data line to the engine control.
In addition, the electronic monitoring apparatus can also monitor the finctionat capability of
the catalytic converter from the measured data in the catalytic converter and optionally from
data from the engine control delivered over data feed or supply lines, and carry the outcome of
this monitoring to a display or a memory over a diagnosis line.

engine parameters

Fig. 101 (from W09114855)

The method of W09114855 (1991) refers to monitoring of the hnctionality of an electrically
heated metallic catalytic converter of the honeycomb type and comprises the steps of

1) selecting at least two measurement locations at respective three-dimensionally spaced-apart
cross-sectional regions of the exhaust pipe, where at least one of the temperature
measurement locations (or even both) is inside the catalytic converter
2) defining at least a partial volume of the catalytic converter of the exhaust system between
the measurement locations being definitive for catalytic conversion of pollutants in the
exhaust gas, with at least 50% of the active catalytic converter volume being between the at
least two measurement locations