| 摘要 |
The invention relates to a method for determining the light-off temperature of a catalytic converter on a motor vehicle. Said method makes it possible to determine the aging condition of the catalytic converter. In order to test the catalytic converter, the same is charged with a CO/HC test gas, for example. An axial temperature profile is generated when the additional CO and HC burn on the catalytic converter. The peak position of said temperature profile along the catalytic converter is dependent on the current light-off temperature. The temperature profile travels through the catalytic converter and can be measured as a time-dependent profile at the outlet of the catalytic converter. Conclusions about the original axial temperature profile can be drawn from the time-dependent profile. A calculation program allows the current light-off temperature of the catalytic converter on the vehicle to be determined. The disclosed method has the advantage that the test can be performed at exhaust gas temperatures greatly exceeding the light-off temperature, thus ensuring that the test pulse does not result in increased emissions of harmful substances.
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