Method for monitoring the operation of a sensor
First Claim
1. A method of monitoring NOx, comprising:
- monitoring NOx in an exhaust aftertreatment system of a vehicle with a NOx sensor;
identifying malfunctions in the NOx sensor by monitoring operation of the NOx sensor, comprising the steps of;
representing the operation of the sensor by;
i) storing a plurality of data values, each data value corresponding to a sensor output signal, wherein the step is performed during a time period such that the data values are distributed over a range of possible data values,ii) defining a plurality of discrete intervals within a range of possible data values; and
iii) calculating a frequency of the data values within each interval thus forming a sensor representation;
receiving at least one reference sensor representation; and
comparing the sensor representation with the at least one reference sensor representation.
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Abstract
A method for monitoring the operation of a sensor is provided. The method comprises the step of representing the operation of the sensor by: i) storing a plurality of data values, each data value corresponding to the sensor output signal, wherein said step is performed during a time period such that said data values are distributed over a range of possible data values, ii) defining a plurality of discrete intervals within said range of possible data values; and iii) calculating the frequency of the data values within each interval thus forming a sensor representation. The method further comprises the steps of receiving at least one reference sensor representation; and comparing said sensor representation with said at least one reference sensor representation.
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Citations
18 Claims
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1. A method of monitoring NOx, comprising:
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monitoring NOx in an exhaust aftertreatment system of a vehicle with a NOx sensor; identifying malfunctions in the NOx sensor by monitoring operation of the NOx sensor, comprising the steps of; representing the operation of the sensor by; i) storing a plurality of data values, each data value corresponding to a sensor output signal, wherein the step is performed during a time period such that the data values are distributed over a range of possible data values, ii) defining a plurality of discrete intervals within a range of possible data values; and iii) calculating a frequency of the data values within each interval thus forming a sensor representation; receiving at least one reference sensor representation; and comparing the sensor representation with the at least one reference sensor representation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A sensor system, comprising
a NOx sensor of a vehicle, and a controller for identifying malfunctions in the NOx sensor by monitoring operation of the sensor, the controller comprising a first memory storing a representation of the sensor operation, the sensor representation including a plurality of data values being distributed over a range of possible data values, each data value corresponding to a sensor output signal, and wherein the representation holds information relating to a frequency distribution of the data values within a plurality of discrete intervals, a second memory storing at least one reference sensor representation, and a comparing unit configured to compare the sensor representation with the at least one reference sensor representation.
Specification