Method for determining a functionality of an exhaust gas sensor in an exhaust gas system of an internal combustion engine

A computing unit (130) configured to determine a functionality of an exhaust gas sensor (121) in an exhaust gas system (120) of an internal combustion engine (110) having at least one catalytic converter (122) and a first exhaust gas sensor (121) upstream of the at least one catalytic converter (122) and a second exhaust gas sensor (123) downstream of the at least one catalytic converter (122), by:

• controlling heating of the first and the second exhaust gas sensor (121, 123) to a temperature above a minimum operating temperature of the relevant exhaust gas sensor (121, 123),
• detecting (210) with the first exhaust sensor a first sensor signal of the first exhaust gas sensor (121), detecting (220) with the second exhaust gas sensor a second sensor signal of the second exhaust gas sensor (123), comparing (230) with the computing unit (130) the first and the second sensor signals in an operating period in which a temperature of the at least one catalytic converter (122) does not exceed a temperature threshold value in the range of 0° C. to 200° C.,
• computing with the computing unit (130) a lambda difference between the first and second sensor signals;
• determining (250) with the computing unit (130) a correction value of the first exhaust gas sensor (121) when the lambda difference is between a first threshold value and a second threshold value;
• and
• control the internal combustion engine according to the correction value.

A non-transitory, computer-readable medium containing instructions that when executed by a computer cause the computer to determine a functionality of an exhaust gas sensor (121) in an exhaust gas system (120) of an internal combustion engine (110) having at least one catalytic converter (122) and a first exhaust gas sensor (121) upstream of the at least one catalytic converter (122) and a second exhaust gas sensor (123) downstream of the at least one catalytic converter (122), by:

• controlling heating of the first and the second exhaust gas sensor (121, 123) to a temperature above a minimum operating temperature of the relevant exhaust gas sensor (121, 123),
• detecting (210) with the first exhaust sensor a first sensor signal of the first exhaust gas sensor (121), detecting (220) with the second exhaust sensor a second sensor signal of the second exhaust gas sensor (123), comparing (230) with a computing unit (130) the first and the second sensor signals in an operating period in which a temperature of the at least one catalytic converter (122) does not exceed a temperature threshold value, and
• computing with the computing unit (130) a lambda difference between the first and second sensor signals;
• determining (250) with the computing unit (130) a correction value of the first exhaust gas sensor (121) when the lambda difference is between a first threshold value and a second threshold value;
• and
• controlling the internal combustion engine according to the correction value.