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US 5,399,961 AGranted
Method and arrangement for monitoring the performance loss of an oxygen probe
AssigneeRobert Bosch GmbH
InventorsErnst Wild, Helmut Denz
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AssigneeRobert Bosch GmbH
InventorsErnst Wild, Helmut Denz
Estimating the term…
The invention relates to an arrangement for monitoring the performance loss of an oxygen probe arranged forward of a catalytic converter. The oxygen probe supplies an actual voltage U.sub.-- ACT for a lambda controller for an internal combustion engine and the arrangement includes: a computation unit for computing the time-dependent mean value .vertline.U.sub.-- ACT-U.sub.-- DES .vertline. of the actual voltage U.sub.-- ACT from a desired voltage U.sub.-- DES; and, an evaluation unit for determining the performance loss of the oxygen probe on the basis of the time-dependent mean value. A simple method sequence which can be carried out with the above arrangement includes the step of deeming the probe to have an impermissibly high performance loss when the above-mentioned mean value drops below a threshold value. However, the quotient is preferably formed between the above-mentioned mean value and the mean value .vertline.FR.sub.-- ACT-FR.sub.-- DES.vertline. and the probe is deemed to have too great a performance loss when this quotient drops below a threshold value. The variable .vertline.FR.sub.-- ACT-FR.sub.-- DES.vertline. is the amount of the deviation of the output signal FR.sub.-- ACT of the lambda controller from a desired value FR.sub.-- DES. In this procedure, a very good signal/noise ratio is obtained which permits an especially reliable evaluation of the performance loss of the probe.
A method for monitoring the performance loss of an oxygen probe arranged forward of a catalytic converter, the oxygen probe supplying an actual-value voltage U.sub.-- ACT for a lambda controller of an internal combustion engine, the method comprising the step of:
A method for monitoring the performance loss of an oxygen probe arranged forward of a catalytic converter, the oxygen probe supplying an actual-value voltage U.sub.-- ACT for a lambda controller of an internal combustion engine, the method comprising the steps of:
An arrangement for monitoring the performance loss of an oxygen probe arranged forward of a catalytic converter, the oxygen probe supplying an actual voltage U.sub.-- ACT for a lambda controller for an internal combustion engine, the arrangement comprising:
Dependencies are inferred from the claim text.