Monitoring the Efficiency of the Catalytic Converter

Monitoring The Efficiency Of The Catalytic Converter

In this process the oxygen storage capacity of the TWC (three-way catalytic converter) is determined by comparing the oxygen sensor amplitudes ahead of and 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 amplitude of the sensor ahead of the TWC acts as a reference value and is therefore determined by the same signal path.

The quotient of the rear and front amplitudes, the amplitude ratio, is used as the measurement of quality. The appearance of amplitudes after the TWC is dependent on the momentary load of the storage capacity of the TWC. This load can vary with the engine load and rpm, which is why a load and rpm-dependent (tl/n) evaluation is performed.










NOTE: The relationship between the two sensor voltages is the measurement for the efficiency of the TWC.