Monitoring system for engine exhaust gas purification arrangement - contains fuel-air or oxygen conc. sensors upstream and downstream of catalyser, filter and correlation function system

摘要

The system contains upstream and downstream fuel/air mixture sensors detecting the oxygen conc. or mixture before and after gas cleaning by catalytic conversion. A filter system attenuates signals with frequencies below the frequency band of the fuel/air mixture controller in the sensor output signals. A correlation function computer computes the correlation functions of the filter system output signals. Deterioration of the catalyser, and hence the operation of the gas purification system, is monitored via the value of the correlation function. USE/ADVANTAGE - Monitors deterioration of the fuel/air mixture or oxygen sensor and catalyser during operation of the engine.