Page 270 - Methods For Monitoring And Diagnosing The Efficiency Of Catalytic Converters A Patent - oriented Survey

252 Methods for Monitoring and Diagnosing the Eficiency of Catalytic Converters

Fig. 109 shows the variation of temperature T of the exhaust gases downstream of the catalytic
converter in fbnction of time for the case of an efficient converter with a brief additional
injection of fuel (curve I), for the case of an efficient converter without a brief additional
injection of fbel (curve 2) and for the case of a deteriorated converter with a brief additional
injection of fbel (curve 3). During time period tlz, curves 1 and 2 are identical. At time point tz,
a temperature rise DT is observed for curve 1 when compared to curve 1 due to the additional
injection of fuel. For curve 3, despite the additional injection, the curve is similar to curve 1
and it is also clearly shifted toward lower temperatures.