Temperature estimation apparatus for aeroplane gas turbine engine

An apparatus for estimating temperature for an aeroplane gas turbine engine mounted on an aircraft and having a combustion chamber, a high-pressure turbine rotated by high-pressure gas exhausted from the combustion chamber, and a low-pressure turbine located downstream of the high-pressure turbine to be rotated by low-pressure gas which has passed through the high-pressure turbine, comprising:

• means for detecting a rotational speed of the low-pressure turbine (N1);
• means for detecting an ambient temperature of the engine (T1);
• means for detecting an outlet temperature of the low-pressure turbine (EGT);
• means for detecting a rotational speed of the high-pressure turbine (N2);
• means for detecting an atmospheric pressure (P0);
• means for calculating a low-pressure turbine outlet temperature change (dEGT) based on at least the detected low-pressure turbine rotational speed (N1) and the ambient temperature (T1);
• means for calculating a model outlet temperature (MODEL-EGTC) based on at least a corrected high-pressure turbine rotational speed (N2C) obtained by correcting the detected high-pressure turbine rotational speed (N2) by the detected ambient temperature (T1) and the detected atmospheric pressure (P0), and for calculating a model outlet temperature difference (dEGTC) by subtracting the calculated model outlet temperature (MODEL-EGTC) from a corrected low-pressure turbine outlet temperature (EGTC) obtained by correcting the detected low-pressure turbine outlet temperature (EGT) by the detected ambient temperature (T1);
• means for calculating a correction amount (dEGTad) relative to the calculated model outlet temperature difference (dEGTC) based on the calculated model outlet temperature difference (dEGTC) and the detected low-pressure turbine rotational speed (N1);
• and
• means for calculating an estimation value of the low-pressure turbine inlet temperature (ITT) based on at least the detected low-pressure turbine outlet temperature (EGT), the calculated outlet temperature change (dEGT) and the correction amount (dEGTad) relative to the calculated model outlet temperature difference (dEGTC).

A method for estimating temperature for an aeroplane gas turbine engine mounted on an aircraft and having a combustion chamber, a high-pressure turbine rotated by high-pressure gas exhausted from the combustion chamber, and a low-pressure turbine located downstream of the high-pressure turbine to be rotated by low-pressure gas which has passed through the high-pressure turbine, comprising the steps of:

• detecting a rotational speed of the low-pressure turbine (N1);
• detecting an ambient temperature of the engine (T1);
• detecting an outlet temperature of the low-pressure turbine (EGT);
• detecting a rotational speed of the high-pressure turbine (N2);
• detecting an atmospheric pressure (P0);
• calculating a low-pressure turbine outlet temperature change (dEGT) based on at least the detected low-pressure turbine rotational speed (N1) and the ambient temperature (T1);
• calculating a model outlet temperature (MODEL-EGTC) based on at least a corrected high-pressure turbine rotational speed (N2C) obtained by correcting the detected high-pressure turbine rotational speed (N2) by the detected ambient temperature (T1) and the detected atmospheric pressure (P0), and calculating a model outlet temperature difference (dEGTC) by subtracting the calculated model outlet temperature (MODEL-EGTC) from a corrected low-pressure turbine outlet temperature (EGTC) obtained by correcting the detected low-pressure turbine outlet temperature (EGT) by the detected ambient temperature (T1);
• calculating a correction amount (dEGTad) relative to the calculated model outlet temperature difference (dEGTC) based on the calculated model outlet temperature difference (dEGTC) and the detected low-pressure turbine rotational speed (N1);
• and
• calculating an estimation value of the low-pressure turbine inlet temperature (ITT) based on at least the detected low-pressure turbine outlet temperature (EGT), the calculated outlet temperature change (dEGT) and the correction amount (dEGTad) relative to the calculated model outlet temperature difference (dEGTC).