Context
During the test phase of the catalytic converters, the customer used a pressure measurement to decide when the catalytic converter should be replaced. However, this pressure measurement came from an additional sensor added exceptionally for the test phase. This sensor was not normally available, and the aim was to replace it with a software sensor.
Need
To detect/anticipate failure from measurements other than the pressure used, to see if there was redundancy between the sensors. The aim was to find out whether it was possible to detect this fault from sensors already present in the engine.
Solution
DiagFit proposed two ways to solve this problem. The first method was to create a virtual sensor calculated from the available sensors to simulate the pressure. The second method was the creation of a normality space, derived from the nominal operation of the catalytic converter, to measure a deviation as the failures were approached.
Results
All kinds of failures (6) with a zero false positive rate were anticipated regardless of the solution used.
