Page 54 - Methods For Monitoring And Diagnosing The Efficiency Of Catalytic Converters A Patent - oriented Survey

36 Methods for Monitoring and Diagnosing the Eficiency of Catalytic Converters

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Exhaust flow

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Fig. 13 (from [I], p. 175)

Usually an internal heating element is added to the sensor in order to minimize the time needed
to reach the operating temperature after a cold start. For a typical four cylinder car driven on
the FTP ‘75 test cycle, use of a heated sensor reduces the time required to achieve the
operating temperature from SO to 30 sec after a cold start up. The steady state output voltage
of the sensor (Table 8 [I]), as well as its response, depends also on the concentration of the