Catalytic Converter: Description and Operation

Monitoring The Efficiency Of The Catalytic Converter

In this process the oxygen storage capacity of the TWC (three-way catalytic converter) is determined from the signal characteristic of the oxygen sensor after the TWC. If the oxygen storage capacity of the TWC is greatly reduced due to aging, voltage amplitudes also occur at the oxygen sensors after the TWC.

The appearance of amplitudes after the TWC is dependent on the momentary load of the TWC's storage capacity. This load can vary with the engine load and rpm, which is why a load and rpm-dependent (rl/n) evaluation is performed.