US 12,270,346 B2
Method for monitoring a starting sequence of a turbomachine and monitoring system implementing said method
Marion Marguerite Jedruszek, Moissy Cramayel (FR); Jérôme Henri Noël Lacaille, Moissy Cramayel (FR); and Thomas Louis Gaston Dumargue, Moissy Cramayel (FR)
Assigned to SAFRAN AIRCRAFT ENGINES, Paris (FR)
Appl. No. 17/794,101
Filed by SAFRAN AIRCRAFT ENGINES, Paris (FR)
PCT Filed Dec. 21, 2020, PCT No. PCT/FR2020/052583
§ 371(c)(1), (2) Date Jul. 20, 2022,
PCT Pub. No. WO2021/148731, PCT Pub. Date Jul. 29, 2021.
Claims priority of application No. 2000525 (FR), filed on Jan. 20, 2020.
Prior Publication US 2023/0051801 A1, Feb. 16, 2023
Int. Cl. F02C 7/26 (2006.01); F01D 19/00 (2006.01); F02C 7/264 (2006.01)
CPC F02C 7/26 (2013.01) [F01D 19/00 (2013.01); F02C 7/264 (2013.01); F05D 2260/85 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A method for monitoring a starting sequence of a turbomachine comprising a compressor provided with a rotor, a starter capable of rotating the rotor and a combustion chamber wherein a mixture of air and fuel is ignited by an ignition device, the method comprising:
acquiring a measurement signal of an engine speed of the rotor during the starting sequence;
determining a bracketing of a time zone during which an ignition instant takes place, the bracketing being defined by a lower limit corresponding to a first event necessarily taking place before an ignition instant and an upper limit corresponding to a second event necessarily taking place after the ignition instant; and
determining, between the lower limit and the upper limit, a break point in a variation with time of the measurement signal, said break point corresponding to the ignition instant of the air-fuel mixture in the combustion chamber,
determining a break point in the variation with time of the measurement signal comprising:
a) determining a sliding window which is displaced between the lower limit and the upper limit,
b) dividing the sliding window into a first half-window and a second half-window, each one of the first half-window and the second half-window containing a portion of the measurement signal corresponding to a curve portion,
c) approximating each curve portion by a separate polynomial and determining a dominant coefficient of each one of the curve portions,
d) comparing the dominant coefficient of the curve portion of the first half-window with the dominant coefficient of the curve portion of the second half-window, and
e) reiterating steps b)-d) until the sliding window has slid over an entire length of the time zone, and then identifying a half-window from the first and second half-windows of which the two dominant coefficients are the most different, said half-window containing the break point in the variation with time of the measurement signal.