Active method of three way catalyst monitoring by use of wideband combustion mixture composition sensor

In this paper the active method of three way catalyst monitoring by use of wideband combustion mixture composition sensor was described. This method relays on three way catalyst activity decrease by determination of it oxygen capacity decrease monitoring. Determination of catalyst oxygen capacity decrease was done by comparison of signals from wideband and binary combustion mixture composition sensors. These sensors were mounted before and after investigated catalyst. In this paper was described the test bench in which modified catalyst was used. The catalyst was modified to simulate it activity decrease. Paper contains the investigation procedure and also static and dynamic characteristics of wideband combustion mixture composition sensor. A hand of received results the characteristic of binary combustion mixture composition sensor reaction time on combustion mixture change in function of reactor activity was determinate. From received results the index of reactor oxygen capacity decrease was also determinate. Received results showed also that this method can be used for precise controlling of three way catalysts activity for on board diagnostic systems purposes. Additionally this method allows concluding on toxic gases emission in NEDC tests at steady state engine work cycle.