System for monitoring the efficiency of a catalyst, in particular for motor vehicles.

摘要

The efficiency of a catalyst (C) is assessed on the basis of the output signals of two lambda sensors (2, 3) disposed upstream (2) and downstream (3) respectively of the catalyst (C). In particular, a signal obtained by calculating the mean quadratic deviations (MQD2, MQD3) of the output signals of the sensors (2, 3) is used as the signal indicative of the efficiency.