Method for the diagnosing of a catalytic converter located in an exhaust gas flow, and device for carrying out said method
AssigneeRobert Bosch GmbH
InventorsJoerg Frauhammer, Uwe Mueller
Life of this patent
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Abstract
Disclosed are a method and a device for diagnosing a catalytic converter (15, 16, 17) located in a exhaust gas flow (ms_abg). Said method and device are based on an evaluation of the hygroscopic properties of the catalytic converter (15, 16, 17).
Claims15
1-14. (canceled)
A method of diagnosing a catalytic converter arranged in an off-gas stream, the method comprising:
- evaluating a catalytic converter hygroscopic characteristic.
A method according to claim 1, further comprising obtaining at least one measurement of a dimension for a temperature of the catalytic converter and evaluating at least one parameter of a measured temperature-plateau that occurs during the evaporation of a water film in the catalytic converter.
A method according to claim 2, further comprising using a plateau-temperature as the at least one parameter of a measured temperature-plateau.
A method according to claim 2, further comprising using a plateau-length as the at least one parameter of a measured temperature-plateau.
A method according to claim 4, wherein the plateau-length of a measured temperature-plateau is ascertained if one or more of the following conditions are within a range of tolerance during ascertainment of the temperature-plateau:
- a. the off-gas stream;
- b. an exhaust gas temperature upstream before the catalytic converter;
- or
- c. a temperature of a combustion engine that has the catalytic converter arranged in an exhaust gas area.
A method according to claim 5, wherein the range of tolerance is a function of one or more of the following parameters:
- a. the off-gas stream;
- b. the exhaust gas temperature;
- or
- c. the temperature of the combustion engine at the beginning of the ascertainment of the temperature-plateau.
A method according to claim 1, further comprising scheduling the catalytic converter diagnosis after a cold start of a combustion engine that has the catalytic converter arranged in an off-gas stream area.
A method according to claim 1, further comprising scheduling the catalytic converter diagnosis after a boost deactivation of a combustion engine that has the catalytic converter arranged in an off-gas stream area.
A method according to claim 1, further comprising scheduling the catalytic converter diagnosis after a turning off and a restarting of a combustion engine that has the catalytic converter arranged in an off-gas stream area.
A method according to claim 1, further comprising scheduling the catalytic converter diagnosis when the off-gas stream is below a threshold.
A method according to claim 1, wherein the catalytic converter is divided into at least two catalytic converter sections and in that the catalytic converter diagnosis takes place separately for each catalytic converter section.
A method according to claim 2, further comprising scheduling the ascertainment of the temperature-plateau after the catalytic converter temperature has sunken below a temperature-plateau expectancy value of the temperature-plateau.
A method according to claim 12, wherein the temperature-plateau expectancy value is adapted depending on a plateau-temperature diagnose signal.
A device, especially at least one customized controller, for the implementation of a method of diagnosing a catalytic converter arranged in an off-gas stream, the method comprising:
- evaluating a catalytic converter hygroscopic characteristic.
Dependencies are inferred from the claim text.