Method and device for diagnosing the measuring ability of an exhaust gas sensor

A method for diagnosing a measuring ability of an exhaust gas sensor in an exhaust gas channel of an internal combustion engine, the sensor having a storage volume in a reference gas channel, at least one first electrode facing an electrode cavity connected to the exhaust gas channel and a second electrode facing the reference gas channel, comprising:

• applying such a high voltage between the first electrode and the second electrode in a first phase that the reference gas channel is filled with additional oxygen due to a decomposition of at least one of water and carbon dioxide;
• and
• in a second phase, evaluating the measuring ability using a pump current in a circuit containing the first electrode and the second electrode;
• wherein the second phase is used with an oxygen transport from the reference gas channel to the electrode cavity for evaluating a rich measuring ability of the exhaust gas sensor.

A method for diagnosing a measuring ability of an exhaust gas sensor in an exhaust gas channel of an internal combustion engine, the sensor having a storage volume in a reference gas channel, at least one first electrode facing an electrode cavity connected to the exhaust gas channel and a second electrode facing the reference gas channel, comprising:

• applying such a high voltage between the first electrode and the second electrode in a first phase that the reference gas channel is filled with additional oxygen due to a decomposition of at least one of water and carbon dioxide;
• and
• in a second phase, evaluating the measuring ability using a pump current in a circuit containing the first electrode and the second electrode;
• wherein in the evaluation of the measuring ability of the exhaust gas sensor, a capacitive charge-reversal current flowing through at least one of the first supply line and the second supply lines, is taken into account when there is a change in the voltage between the first electrode and the second electrode.

A method for diagnosing a measuring ability of an exhaust gas sensor in an exhaust gas channel of an internal combustion engine, the sensor having a storage volume in a reference gas channel, at least one first electrode facing an electrode cavity connected to the exhaust gas channel and a second electrode facing the reference gas channel, comprising:

• applying such a high voltage between the first electrode and the second electrode in a first phase that the reference gas channel is filled with additional oxygen due to a decomposition of at least one of water and carbon dioxide;
• and
• in a second phase, evaluating the measuring ability using a pump current in a circuit containing the first electrode and the second electrode;
• wherein the method is used for diagnosing a rich measuring ability of a lambda sensor in an exhaust gas channel of an internal combustion engine.

A method for diagnosing a measuring ability of an exhaust gas sensor in an exhaust gas channel of an internal combustion engine, the sensor having a storage volume in a reference gas channel, at least one first electrode facing an electrode cavity connected to the exhaust gas channel and a second electrode facing the reference gas channel, comprising:

• applying a voltage between the first electrode and the second electrode in a first phase, wherein in the first phase, the applied voltage being such a high voltage that the reference gas channel is filled with additional oxygen due to a decomposition of at least one of water and carbon dioxide;
• and
• in a second phase which follows the first phase, reducing the voltage applied between the first electrode and the second electrode from the high voltage, and evaluating the measuring ability of the exhaust gas sensor using a pump current in a circuit containing the first electrode and the second electrode, wherein during the second phase, oxygen transports from the reference gas channel to the electrode cavity;
• wherein during the second phase, conditions prevail at the exhaust gas sensor as would have prevailed in the case of a rich exhaust gas mixture, but without applying an actual rich exhaust gas mixture to the exhaust gas sensor.