Synchronization of aircraft engines
Methods and related apparatus for improving synchronization of two or more engines on an aircraft are disclosed. Such method may be used where each engine comprises a first spool and a second spool, and, where a rotational speed of a first spool of a first engine has been substantially synchronized with a rotational speed of a first spool of a second engine. An exemplary method comprises receiving a value of a sensed parameter useful in controlling the first engine; adding a bias to the value; and using the biased value for controlling the first engine to cause a change in rotational speed of the second spool of the first engine in relation to the rotational speed of the first spool of the first engine.
1. A method for improving synchronization of two engines on an aircraft where each engine comprises a first spool and a second spool, and, where a rotational speed of a first spool of a first engine has been substantially synchronized with a rotational speed of a first spool of a second engine, the method comprising:
receiving a value of a sensed parameter useful in controlling the first engine, the sensed parameter being indicative of one of altitude and a flow of bleed air from the first engine;
adding a bias to the value; and
using the biased value for controlling the first engine to cause a change in rotational speed of the second spool of the first engine in relation to the rotational speed of the first spool of the first engine and thereby reduce a difference in rotational speed between the second spool of the first engine and the second spool of the second engine.
2. The method as defined in claim 1 , comprising determining the bias based on a difference in rotational speed between the second spool of the first engine and the second spool of the second engine.
3. The method as defined in claim 1 , comprising determining the bias based on the value of the sensed parameter.
4. The method as defined in claim 1 , comprising receiving feedback indicative of the difference in rotational speed between the second spool of the first engine and the second spool of the second engine.
5. The method as defined in claim 4 , wherein the feedback is based on a vibration measurement acquired on the aircraft.
6. The method as defined in claim 4 , wherein the feedback is based on an acoustic measurement acquired from inside of a cabin of the aircraft.
7. The method as defined in claim 6 , wherein the acoustic feedback is indicative of a period of audible beats inside of the cabin of the aircraft.
8. The method as defined in claim 4 , wherein the feedback is based on a first vibration measurement acquired from the first engine and a second vibration measurement acquired from the second engine.
9. The method as defined in claim 8 , wherein the feedback is based on a combination of the first vibration measurement and of the second vibration measurement.
10. The method as defined in claim 4 , comprising determining the bias based on the feedback.
11. The method as defined in claim 4 , comprising determining a preferred synchronization time based on the feedback and using the biased value for controlling the first engine based on the preferred synchronization time.
12. The method as defined in claim 11 , wherein the preferred synchronization time corresponds to a preferred phase angle between the second spool of the first engine and the second spool of the second engine.
13. The method as defined in claim 11 , wherein the feedback is indicative of a first time corresponding to a higher noise level and a second time corresponding to a lower noise level, the preferred synchronization time corresponding to the time of the lower noise level.
14. The method as defined in claim 1 , wherein the bias is a constant bias for use for a plurality of flight cycles of the aircraft.
15. The method as defined in claim 1 , comprising receiving the bias from a pilot of the aircraft.
16. The method as defined in claim 1 , comprising determining the bias automatically using a feedback loop.
17. A method for improving synchronization of two engines on an aircraft where each engine comprises a first spool and a second spool, and, where a rotational speed of a first spool of a first engine has been substantially synchronized with a rotational speed of a first spool of a second engine, the method comprising:
receiving an out-of-sync signal indicative of the second spool of the first engine and the second spool of the second engine having different rotational speeds;
determining, based on the out-of-sync signal, a bias to be added to a sensed parameter useful in controlling the first engine, the sensed parameter being indicative of one of altitude and a flow of bleed air from the first engine; and
generating an output configured to instruct a controller of the first engine to use the bias with the sensed parameter for controlling the first engine to cause a change in rotational speed of the second spool of the first engine in relation to the rotational speed of the first spool of the first engine.
18. The method as defined in claim 17 , wherein the out-of-sync signal is indicative of a magnitude of the difference in rotational speeds.
19. The method as defined in claim 17 , comprising determining the bias based on the sensed parameter.
20. The method as defined in claim 17 , wherein the out-of-sync signal is based on a vibration measurement acquired on the aircraft.
21. The method as defined in claim 17 , wherein the out-of-sync signal is based on an acoustic measurement acquired from inside of a cabin of the aircraft.
22. The method as defined in claim 21 , wherein the out-of-sync signal is indicative of a period of audible beats inside of the cabin of the aircraft.
23. The method as defined in claim 17 , wherein the out-of-sync signal is based on a first vibration measurement acquired from the first engine and a second vibration measurement acquired from the second engine.
24. The method as defined in claim 23 , wherein the out-of-sync signal is based on a combination of the first vibration measurement and of the second vibration measurement.
25. The method as defined in claim 17 , comprising determining a preferred synchronization time based on the out-of-sync signal and generating the output based on the preferred synchronization time.
26. The method as defined in claim 25 , wherein the preferred synchronization time corresponds to a preferred phase angle between the second spool of the first engine and the second spool of the second engine.
27. The method as defined in claim 25 , wherein the out-of-sync signal is indicative of a first time corresponding to a higher noise level and a second time corresponding to a lower noise level, the preferred synchronization time corresponding to the time of the lower noise level.
28. The method as defined in claim 17 , comprising retrieving the bias from a look-up table.
29. The method as defined in claim 17 , comprising determining the bias automatically using a feedback loop.