Exhaust gas catalytic converter diagnosis for vehicle, involves adjusting amplitude and frequency of engine-lambda vibration such that change in temperature of catalytic converter takes place with unaged catalytic converter

摘要

The process involves changing the normal operation mode of an internal combustion engine (1) into a diagnostic operation mode. A temperature of an exhaust gas catalytic converter (3) is determined in the normal and diagnostic operation modes. An amplitude and frequency of engine-lambda vibration are adjusted in the diagnostic operation mode such that a change in temperature of the converter takes place with an unaged catalytic converter.