DEVICE AND METHOD FOR DIAGNOSING THE CONDITION OF A PROBE UPSTREAM FROM A CATALYTIC CONVERTER

摘要

A device and a method for use in internal combustion injection engines comprising an exhaust pipe catalytic converter and a non-linear probe upstream therefrom. The device and method are useful for diagnosing the condition of the upstream probe (16) using a signal (Vdown) from a second non-linear probe (26) downstream from the catalytic converter (14). For this purpose, the signal from the downstream probe (26) is processed to give a signal (KRICH) that is filtered (32) to provide a signal (KRICHF). Said signal (KRICHF) is in turn compared (40) with maximum and minimum values and the upstream probe is considered to be correct if the signal falls between said values, or faulty if it falls outside the same. Said device and method are useful in injection engines fitted with a catalytic converter and upstream and downstream non-linear probes.