Diagnostic method for an exhaust gas probe and diagnostic device for an exhaust gas probe

• Main Authors: SIEBER NORBERT, ROESEL GERD
• Format: Patent
• Language: English
• Published: 03.03.2009
• Subjects: BLASTING; CALCULATING; CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TOTRANSPORTATION; COMBUSTION ENGINES; COMPUTING; CONTROLLING COMBUSTION ENGINES; COUNTING; ELECTRIC DIGITAL DATA PROCESSING; ENGINE PLANTS IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNALCOMBUSTION ENGINES; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES ORENGINES IN GENERAL; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; HEATING; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS; LIGHTING; MACHINES OR ENGINES IN GENERAL; MECHANICAL ENGINEERING; PHYSICS; STEAM ENGINES; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE; WEAPONS

An exhaust gas probe is disposed downstream of a catalytic converter in an exhaust gas tract of an internal combustion engine. A first quality value which is representative of a signal dynamic of the measured signal of the exhaust gas probe is determined as a function of the measured signal of the exhaust gas probe. If the first quality value represents at least one predefined signal dynamic, the exhaust gas probe is diagnosed as functioning correctly. If the first quality value does not represent at least the predefined signal dynamic, a catalytic converter diagnosis is performed comprising a loading with oxygen and/or an emptying of oxygen with at least two different air/fuel ratios. Dependent on the catalytic converter diagnosis, the exhaust gas probe is diagnosed as functioning either correctly or incorrectly.