Turbomachine comprising a monitoring system comprising a module for engaging a protection function of the turbomachine and monitoring method

Abstract

An aircraft turbine engine including at least one spool rotating at speed N1 and a monitoring system including: a regulating module including at least one regulation measurement channel to obtain a measurement of the speed N1 and a mechanism to compare the obtained speed measurement with a thrust setpoint to provide a thrust status; and a module for engaging a protection function of UHT or ATTCS type of the turbine engine. The turbine engine further includes a system for protection against overspeed to prevent ejection of high-energy debris outside the turbine engine, the protection system including at least one overspeed measurement channel to obtain an overspeed of the rotating spool of the turbine engine. The engagement module compares at least one overspeed obtained with at least one reference speed defined according to the protection function to be engaged, to engage the protection function according to results of the comparison.

Claims

1. An aircraft turbine engine comprising: at least one spool rotating at speed N1; and a monitoring system comprising: a regulating module comprising a first regulation measurement channel configured to obtain a measurement of the speed N1 and a second regulation measurement channel, independent of the first measurement channel, configured to obtain a measurement of the speed N1, and means for comparing the obtained speed measurements with a thrust setpoint to provide a thrust status; and an engagement module for engaging an anti-overthrust or anti-loss of thrust protection function of the turbine engine; a system for protection against overspeed to prevent ejection of high-energy debris outside said turbine engine, the protection system comprising at least one overspeed measurement channel configured to obtain an overspeed of the rotating spool of the turbine engine; and means for providing at least one measurement of overspeed on the basis of the overspeed obtained when one of the regulation measurement channels is defective, wherein the engagement module comprises at least one means for comparison of said overspeed measurement with at least one reference speed defined according to the protection function to be engaged, said engagement module configured to engage said protection function according to results of the comparison.

2. The turbine engine according to claim 1, wherein the system for protection against the overspeed comprises a first overspeed detection channel configured to obtain an overspeed of the rotating spool of the turbine engine and a second overspeed detection channel, independent of the first overspeed detection channel, configured to obtain an overspeed of the rotating spool of the turbine engine, the engagement module comprising means for comparison of the two overspeeds obtained with the reference speed defined according to the protection function to be engaged.

3. The turbine engine according to claim 1, wherein the system for protection against overspeed comprises a first overspeed detection channel configured to obtain an overspeed of the rotating spool of the turbine engine and a second overspeed detection channel, independent of the first overspeed detection channel, configured to obtain an overspeed of the rotating spool of the turbine engine, said system for protection against overspeed being configured to supply a consolidated overspeed to the engagement module of the monitoring system according to the overspeeds obtained on the overspeed measurement channels and the engagement module comprising means for comparison of the consolidated overspeed obtained with the reference speed defined according to the protection function to be engaged.

4. The turbine engine according to claim 1, wherein the overspeed measurement channel is independent of the regulation measurement channels.

5. The turbine engine according to claim 1, wherein for the engagement of the anti-overthrust function of the turbine engine, the comparison means of the engagement module is configured to compare at least one overspeed obtained with a safety speed corresponding to a maximum permitted overthrust for the turbine engine.

6. The turbine engine according to claim 1, comprising at least one communication link with another similar turbine engine in order to communicate to each other the value of the speed of their rotating spool, a turbine engine in which for the engagement of the anti-loss of thrust function of said turbine engine, the comparison means of the engagement module are configured in order to compare at least one obtained overspeed of said turbine engine with the speed of said other turbine engine obtained by the communication link.

7. A method for monitoring an aircraft turbine engine including at least one spool rotating at speed N1, said method comprising: obtaining a first measurement of speed of the rotating spool according to a first regulation measurement channel of a monitoring system of the speed N1 and at least a second measurement of the speed of the rotating spool according to a second regulation measurement channel of said monitoring system, independent of the first measurement channel; comparing the measurement of speed obtained with a thrust setpoint to supply a thrust status; obtaining a first overspeed of the rotating spool according to a first overspeed detection channel of a system for protection against overspeed configured to prevent ejection of high-energy debris outside said turbine engine, and a second overspeed of the rotating spool of the turbine engine according to a second overspeed detection channel of the same protection system, independent of the first overspeed detection channel; engaging an anti-overthrust or anti-loss of thrust protection function of the turbine engine using the two overspeed values obtained to compare the overspeed measurement with at least one reference speed defined according to the protection function to be engaged.

8. A method for monitoring an aircraft turbine engine including at least one spool rotating at speed N1, said method comprising: obtaining a first measurement of speed of the rotating spool according to a first regulation measurement channel of a monitoring system of the speed N1 and at least a second measurement of the speed of the rotating spool according to a second regulation measurement channel of said monitoring system, independent of the first measurement channel; comparing the speed measurements obtained with a thrust setpoint to supply a thrust status; obtaining an overspeed of the rotating spool according to at least a first overspeed measurement channel, independent of the regulation measurement channels, of a system of protection against overspeed configured to prevent ejection of high-energy debris outside said turbine engine; and engaging an anti-overthrust or anti-loss of thrust protection function of the turbine engine by comparison of said overspeed obtained with at least one reference speed defined according to the protection function to be engaged.

Description

(1) The invention will be better understood on reading the following description given solely by way of example and with reference to the accompanying drawings, in which:

(2) FIG. 1 is a schematic illustration of the reliability of a turbojet engine monitoring system for the engagement of a UHT function according to the prior art (already mentioned);

(3) FIG. 2 is a schematic illustration of the reliability of a turbojet engine monitoring system for the engagement of a function ATTCS according to the prior art (already mentioned);

(4) FIG. 3 is a schematic illustration of the reliability of a turbojet engine monitoring system for the engagement of a function ATTCS according to the prior art in “dispatch” mode (already mentioned);

(5) FIG. 4 is a schematic illustration of the reliability of a turbojet engine monitoring system for the engagement of a function UHT according to the prior art in “dispatch” mode (already mentioned);

(6) FIG. 5 is a schematic illustration of the reliability of a turbojet engine monitoring system for the engagement of a function UHT according to the invention;

(7) FIG. 6 is a schematic illustration of the reliability of a turbojet engine monitoring system for the engagement of a function UHT according to the invention in “dispatch” mode;

(8) FIG. 7 is a schematic illustration of the reliability of a turbojet engine monitoring system for the engagement of a function ATTCS according to the invention;

(9) FIG. 8 is a schematic illustration of the reliability of a turbojet engine monitoring system for the engagement of a function ATTCS according to the invention in “dispatch” mode;

(10) FIG. 9 is a schematic illustration of a turbojet engine monitoring system for the engagement of a function UHT or ATTCS according to the invention in “dispatch” mode.

(11) It should be noted that the drawings disclose the invention in a detailed manner for implementing the invention, but said drawings can of course serve to give a better definition of the invention where appropriate.

(12) The invention will be presented for a turbojet engine with a twin spool but it applies to any aircraft turbine engine having at least one rotating spool.

(13) In this example, the turbojet engine with a twin spool comprises a low-pressure spool and a high-pressure spool, the speed of rotation of the low-pressure spool being known to the person skilled in the art under the designation of speed N1. As set out above, the monitoring of the speed N1 makes it possible to initiate a plurality of functions for protection of the turbojet engine if an anomaly is detected.

(14) As illustrated in FIGS. 5 to 8, the turbojet engine comprises a monitoring system 1 which comprises a regulating module REG for regulation of the speed N1 intended to regulate the speed of the turbojet engine according to a setpoint N1.sub.CONS provided by the pilot of the aircraft and an engagement module ENG of a protection function in order to correct an operating anomaly of the turbojet engine based on the speed N1 of the turbojet engine.

(15) Regulating Module REG of the Speed N1

(16) The regulating module REG of the monitoring system 1 is a regulation module similar to the prior art which comprises a first regulation measurement channel A suitable for obtaining a measurement N1.sub.A of the speed N1 and a second regulation measurement channel B suitable for obtaining a measurement N1.sub.B of the speed N1.

(17) The regulating module REG of the monitoring system 1 also comprises means 2A, 2B for comparison of measurements of speed N1.sub.A, N1.sub.B obtained with a thrust setpoint N1.sub.cons in order to supply a turbojet engine thrust status E.sub.REG at the output. As shown in FIGS. 5 to 8, a logic gate ET (reference E2) makes it possible to consolidate the information deduced by the comparison means 2A, 2B.

(18) By way of example, if the thrust setpoint N1.sub.cons is equal to 4,000 rpm and the speed measurements N1.sub.A, N1.sub.B obtained are respectively equal to 2,000 rpm and 1000 rpm, the regulating module REG supplies a thrust status E.sub.REG indicating a loss of thrust of the turbojet engine. If only the regulation measurement channel A had indicated a loss of thrust, the thrust status E.sub.REG would not have indicated a loss of thrust (gate ET between the two channels A, B).

(19) Conventionally, each regulation measurement channel A, B comprises its own acquisition means and its own speed sensors. The regulating module REG is conventionally in the form of a regulating computer, of the FADEC type, mounted on the turbojet engine.

(20) Module for Engagement of a Protection Function

(21) According to the invention, the module ENG for engagement of a protection function, of the UHT or ATTCS type, is independent of the regulation measurement channels A, B of the regulating module REG. In fact, according to the invention, the engagement of the protection function depends upon measurements of overspeed of the rotating spool of the turbojet engine in order to prevent the ejection of high-energy debris outside the turbojet engine and, in particular, towards the aircraft on which the turbojet engine is mounted.

(22) Conventionally, the protection against overspeed is implemented by an electronic protection system which is independent of the monitoring system 1 enabling the regulation and the engagement of the protection functions UHT and ATTCS. A system for protection against overspeed is for example known from the patent application FR2960906 in the name of SNECMA.

(23) In a known manner, the overspeed of the low-pressure spool of the turbojet engine is detected by a first overspeed detection channel AS and by a second overspeed detection channel BS in order to prevent the ejection of high-energy debris outside the turbojet engine. Conventionally, each overspeed detection channel AS, BS comprises its own acquisition means and its own speed sensors. The overspeed detection channels AS, BS are respectively suitable for obtaining overspeeds N1.sub.As, N1.sub.Bs of the rotating spool of the turbine engine as illustrated in FIGS. 5 to 8.

(24) According to the invention, the overspeed detection channels AS, BS of the overspeed protection system are connected to the module ENG for engagement of a protection function. Thus, the overspeeds N1.sub.AS, N1.sub.BS, which are values of the speed of rotation of the low-pressure spool, serve as a basis for the engagement of the protection function and are independent of the speed N1.sub.A, N1.sub.B obtained for the regulating module REG, which increases the reliability of the monitoring system 1.

(25) Conventionally, the engagement module ENG comprises comparison means 3A, 3B which are suitable for comparing the overspeeds obtained N1.sub.AS, N1.sub.BS with at least one reference speed which is predetermined according to the protection function to be engaged (UHT, ATTCS) as will be set out below.

(26) Engagement of a Protection Function UHT

(27) For the engagement of the protection function UHT, with reference first of all to FIG. 5, the overspeeds obtained N1.sub.AS, N1.sub.BS by the overspeed protection system are each compared with a safety setpoint N1.sub.SEC on the basis of which the protection function UHT is engaged. The safety setpoint N1.sub.SEC for the function UHT is similar to that used in the prior art and corresponds to the maximum speed allowed by the turbojet engine before the function UHT is actuated. When the function UHT is actuated, the fuel supply to the turbojet engine is cut off.

(28) As illustrated in FIG. 5, when overthrust is detected by the engagement module ENG by comparison of the overspeeds N1.sub.AS, N1.sub.BS with the safety setpoint N1.sub.SEC, the UHT protection function is engaged (E.sub.ENG=UHT ACTIVE) in order to avoid a dissymmetry of thrust of the aircraft. As the decision to engage the function UHT is independent of the thrust regulating module REG, the reliability of the monitoring system 1 is improved. Incidentally, the protection function UHT can be engaged even though the thrust status E.sub.REG does not indicate any overthrust.

(29) By way of example, with reference to FIG. 6 all the channels B of the monitoring system have failed in “dispatch” mode, that is to say both the regulation measurement channel B and the overspeed measurement channel BS. By virtue of the monitoring system 1 according to the invention, the regulation module REG and the engagement module ENG have independent speed information N1 in order to define the thrust and activity status of the function UHT, which improves the reliability of the monitoring system 1, and an isolated failure cannot lead to an event of concern as illustrated in FIG. 6.

(30) Engagement of a Protection Function ATTCS

(31) In the following embodiment a first turbojet engine and a second turbojet engine according to the invention are mounted on an aircraft. Each turbojet engine comprises at least one communication link with the other turbojet engine so as to allow a dialogue between the turbojet engines. The communication link makes it possible to communicate the value of the speed N1 of the rotating spool to the other turbojet engine in such a way that the function ATTCS can correct any dissymmetry of thrust. In this example, the two turbojet engines are connected by a communication link of the ARINC type but of course other communication means could be suitable.

(32) Each turbojet engine comprises an overspeed protection system and a monitoring system 1 with its own regulating module REG and its own engagement module ENG. With reference to FIG. 7, for the engagement of the protection function ATTCS on the first turbojet engine, the obtained overspeeds N1.sub.AS, N1.sub.BS of the first turbojet engine are each compared with a reference speed which corresponds to the consolidated speed N1.sub.mot2 of the regulating module REG of the second turbojet engine. In this example, the consolidated speed N1.sub.mot2 is obtained by processing of the speeds measured by the regulation measurement channels A, B of the regulating module REG of the second turbojet engine.

(33) In other words, the first turbojet engine has the value of the speed of rotation N1.sub.mot2 of the low-pressure spool of the second turbojet engine. As illustrated in FIG. 7, due to the means 3A, 3B for comparison of the speeds of the turbojet engines it is then possible to detect a dissymmetry of thrust between the two turbojet engines. In a similar manner to the engagement of the function UHT, by virtue of the monitoring system 1 according to the invention, the regulation module REG and the engagement module ENG have independent speed information N1 in order to define the thrust and activity status of the function ATTCS, which improves the reliability of the monitoring system 1, and an isolated failure cannot lead to an event of concern. The same applies to the engagement of the function ATTCS in “dispatch” mode as shown in FIG. 8.

(34) An electronic device for monitoring the aircraft is shown schematically in FIG. 9. This electronic device is in the form of a computer, for example of the FADEC type, and comprises a monitoring system 1 and a protection system 2. For the sake of clarity, the channels A of the monitoring system 1 are shown in the upper part of the computer whilst the channels B of the monitoring system 1 are shown in the lower part of the computer.

(35) The computer receives at the input measurements of speed N1.sub.A, N1.sub.B by the regulation measurement channels A, B and measurements of overspeeds N1.sub.AS, N1.sub.BS by the overspeed measurement channels AS, BS as illustrated in FIG. 9. These measurements of speed and of overspeed are carried out by measurement sensors S by means of an acquisition system 3, for example an FPGA device (“field-programmable gate array”). The measurement sensors S and the acquisition system 3 are configured in such a way that the measurements of speed N1.sub.A, N1.sub.B and of overspeed N1.sub.AS, N1.sub.BS are carried out independently.

(36) The computer of FIG. 9 is shown in “dispatch” mode, all of the measurement channels B having failed. The failure is represented visually by a cross which strikes through the lower part of the computer. Because of the failure, the monitoring system 1 receives for its regulating module REG only a single measurement of speed N1.sub.A, the measurement of speed N1.sub.B being absent. For its engagement module ENG, the monitoring system 1 only receives a single measurement of overspeed N1.sub.S from the protection system 2, which in this case is equal to the measurement of overspeed N1.sub.AS measured on the channel A of the protection system 2, the measurement of speed N1.sub.BS being absent due to the failure

(37) Still with reference to FIG. 9, the measurements of speed N1.sub.A and of overspeed N1.sub.As are received by the monitoring system 1. As presented above, the regulating module REG of the monitoring system 1 compares the measurement of speed N1.sub.A with a setpoint speed N1.sub.CONS not shown in FIG. 9. The module ENG for engagement of the monitoring system 1 compares the overspeed N1.sub.S—supplied by the protection system 2—with a safety setpoint N1.sub.SEC for the engagement of the function UHT not shown in FIG. 9. With regard to the function ATTCS, the overspeed N1.sub.S supplied by the protection system 2 is compared with the speed of the rotating spool of another turbine engine. In a reciprocal manner, with reference to FIG. 9, the protection system 2 transmits the value of overspeed N1.sub.S to the second turbojet engine by the communication link in such a way that the second turbojet engine can likewise implement the function ATTCS.

(38) By virtue of the invention, the reliability of the monitoring system is increased in all circumstances, in particular in “dispatch” mode, which provides greater safety of the turbojet engine and a better availability of the aircraft on which the turbojet engine is mounted.

(39) The monitoring system 1 and the protection system 2 are preferably electronic systems which are preferably independent but of course they could be combined in the same computer. In a similar manner, the engagement and regulating modules are likewise electronic modules.