Method and system for processing a temperature measurement signal delivered by a sensor

1. A method for processing a measurement signal T 1 of a temperature of a fluid flowing through an aircraft engine delivered by a sensor provided in the aircraft engine, comprising:

digital modeling, by a modeled signal T 2 , of the temperature measured by the sensor;

estimating a lag error signal for the sensor, based on the modeled signal T 2 and a signal T 3 obtained by filtering the modeled signal T 2 , the filtering being parameterized by an estimate of a time constant of the sensor;

obtaining a temperature signal T, by adding to a signal T 4 , derived from the measurement signal T 1 , a product of a real parameter K and a signal resulting from subtracting the signal T 4 from the modeled signal T 2 , such that the temperature signal T=T 4 +K(T 2 −T 4 ) so as to use the measurement signal of the sensor when the measured temperature is stabilized and the sensor is operating in a stabilized manner to obtain the temperature signal T, to use the modeled signal when the sensor is in a transient phase and an inertia of the sensor is felt to obtain the temperature signal T, and the real parameter provides a transition between the two uses; and

controlling the aircraft engine based on the temperature signal,

wherein a value of the parameter K applied during the obtaining varies over time and depends on a value of the estimated lag error signal, said applied value of the parameter K being taken as equal to 0 when the value of the estimated lag error signal is zero and equal to 1 when an absolute value of the estimated lag error signal is greater than a first predetermined threshold.

2. The processing method as claimed in claim 1 , wherein the value of the parameter K varies linearly between the values 0 and 1 as a function of the value of the estimated lag error signal when the absolute value of the lag error signal varies between zero and the first predetermined threshold.

3. The processing method as claimed in claim 1 ,

wherein, when the value of the estimated lag error signal is zero and said temperature is undergoing a succession of rapid variations are detected simultaneously, the value of the parameter K is kept equal to the value that the value of the parameter K had before said detection or is permitted to vary with respect to the value of the parameter K only by a predetermined maximum quantity.

4. The processing method as claimed in claim 3 , further comprising detecting that the temperature is undergoing a succession of rapid variations when a variation in a rotation speed of the aircraft engine is greater than a second predetermined threshold.

5. The processing method as claimed in claim 1 , wherein the signal T 4 is equal to the measurement signal T 1 .

6. The processing method as claimed in claim 1 , wherein the signal T 4 is obtained by adding to the measurement signal T 1 the estimated lag error signal.

7. The processing method as claimed in claim 1 , wherein the time constant of the sensor is estimated in real time based on the measurement signal T 1 and the modeled signal T 2 .

8. The processing method as claimed in claim 7 , wherein the time constant of the sensor is estimated as a function of time by:

(a) obtaining a first signal and a second signal respectively, by derivation with respect to time of the measurement signal T 1 and the modeled signal T 2 respectively;

(b) evaluating a difference between an absolute value of the first signal and an absolute value of the second signal; and

(c) estimating the time constant of the sensor on the basis of the difference.

9. An aircraft engine comprising:

a sensor able to deliver a measurement signal T 1 of a temperature; and

a processing system for processing the measurement signal T 1 of the temperature delivered by the sensor, the processing system comprising:

a digital modeling module, configured to model the temperature measured by the sensor by a modeled signal T 2 ;

an estimating module, configured to estimate a lag error signal for the sensor, based on the modeled signal T 2 and a signal T 3 obtained by filtering the modeled signal T 2 , the filtering being parameterized by an estimate of a time constant of the sensor; and

an obtaining module, configured to obtain a temperature signal T by adding to a signal T 4 , derived from the measurement signal T 1 , a product of a real parameter K and a signal resulting from subtracting the signal T 4 from the modeled signal T 2 such that the temperature signal T=T 4 +K(T 2 −T 4 ) so as to use the measurement signal of the sensor when the measured temperature is stabilized and the sensor is operating in a stabilized manner to obtain the temperature signal T, to use the modeled signal when the sensor is in a transient phase and an inertia of the sensor is felt to obtain the temperature signal T, and the real parameter provides a transition between the two uses,

wherein a value of the parameter K applied by the obtaining module depends on a value of the lag error signal estimated by the estimating module, said value of the parameter K applied by the estimating module being taken as equal to 0 when the value of the lag error signal is zero and equal to 1 when an absolute value of the lag error signal is greater than a first predetermined threshold.

10. The aircraft engine as claimed in claim 9 , further comprising a device for controlling the aircraft engine configured to use the temperature signal obtained by the processing system.