Monitor system for monitoring the starting of a rotary wing aircraft, an aircraft, and a method using the system

Abstract

A method of starting a turboshaft engine (5) of an aircraft (1), said aircraft (1) being provided with a rotary wing, said aircraft (1) having a freewheel (15) interposed in a drive train (10) between said engine (5) and a rotor (2) of said rotary wing (1), said engine (5) comprising a gas generator (6) and a free turbine (9), the drive train (10) including an upstream portion (11) connecting said free turbine (9) to said freewheel (15), the method comprising the following steps: measuring the torque (Tq) exerted on said upstream portion (11), and measuring a speed of rotation (Ng) of said gas generator (6); comparing said torque (Tq) with a torque threshold (Stq) and comparing said speed of rotation (Ng) with a gas generator speed threshold (Sng); and stopping said engine (5) when said torque (Tq) is less than the torque threshold (Stq) and when said speed of rotation (Ng) is greater than the gas generator speed threshold (Sng).

Claims

1. A monitor system for monitoring the starting of a rotary wing aircraft, the aircraft having a rotary wing including a rotor, a turboshaft engine having a gas generator and a free turbine, a drive train for transmitting power between the turboshaft engine and the rotor, and a freewheel interposed in the drive train, the freewheel including a driving portion and a driven portion, and the drive train including an upstream portion connecting the free turbine to the driving portion of the freewheel and a downstream portion connecting the driven portion of the freewheel to the rotor via a gearbox, the monitor system comprising: a first measurement device for measuring a torque (Tq) exerted on the upstream portion of the drive train connecting the free turbine of the turboshaft engine to the driving portion of the freewheel; a second measurement device for measuring a speed of rotation (Ng) of the gas generator; a third measurement device for measuring a speed of rotation (Nr) of the rotor; and a processor configured to compare the torque (Tq) with a torque threshold (Stq), the speed of rotation (Ng) of the gas generator with a gas generator speed threshold (Sng), and the speed of rotation (Nr) of the rotor with a rotor speed threshold; and automatically stop starting of the turboshaft engine when simultaneously the torque (Tq) is less than the torque threshold (Stq) as determined by the processor from the processor comparing the torque (Tq) with the torque threshold (Stq), the speed of rotation (Ng) of the gas generator is greater than the gas generator speed threshold (Sng) as determined by the processor from the processor comparing the speed of rotation (Ng) of the gas generator with the gas generator speed threshold (Sng), and the speed of rotation (Nr) of the rotor is lower than the rotor speed threshold as determined by the processor from the processor comparing the speed of rotation (Nr) of the rotor with the rotor speed threshold.

2. An aircraft comprising: a rotary wing having a rotor; a turboshaft engine having a gas generator and a free turbine; a drive train for transmitting power between the turboshaft engine and the rotor; a freewheel interposed in the drive train, the freewheel including a driving portion and a driven portion; the drive train including an upstream portion connecting the free turbine to the driving portion of the freewheel and a downstream portion connecting the driven portion of the freewheel to the rotor via a gearbox; and a monitor system for monitoring the starting of the aircraft, the monitor system including a first measurement device for measuring a torque (Tq) exerted on the upstream portion of the drive train connecting the free turbine of the turboshaft engine to the driving portion of the freewheel, a second measurement device for measuring a speed of rotation (Ng) of the gas generator, a third measurement device for measuring a speed of rotation (Nr) of the rotor, and a processor configured to compare the torque (Tq) with a torque threshold (Stq), the speed of rotation (Ng) of the gas generator with a gas generator speed threshold (Sng), and the speed of rotation (Nr) of the rotor with a rotor speed threshold; and automatically stop starting of the turboshaft engine when simultaneously the torque (Tq) is less than the torque threshold (Stq) as determined by the processor from the processor comparing the torque (Tq) with the torque threshold (Stq), the speed of rotation (Ng) of the gas generator is greater than the gas generator speed threshold (Sng) as determined by the processor from the processor comparing the speed of rotation (Ng) of the gas generator with the gas generator speed threshold (Sng), and the speed of rotation (Nr) of the rotor is lower than the rotor speed threshold as determined by the processor from the processor comparing the speed of rotation (Nr) of the rotor with the rotor speed threshold.

3. A method of starting a rotary wing aircraft, the aircraft having a rotary wing having a rotor, a turboshaft engine having a gas generator and a free turbine, a drive train for transmitting power between the turboshaft engine and the rotor, and a freewheel interposed in the drive train, the freewheel including a driving portion and a driven portion, and the drive train including an upstream portion connecting the free turbine to the driving portion of the freewheel and a downstream portion connecting the driven portion of the freewheel to the rotor via a gearbox, the method comprising: measuring a torque (Tq) exerted on the upstream portion of the drive train connecting the free turbine of the turboshaft engine to the driving portion of the freewheel with a first measurement device; measuring a speed of rotation (Ng) of the gas generator with a second measurement device; measuring a speed of rotation (Nr) of the rotor with a third measurement device; comparing, by a processor, the torque (Tq) with a torque threshold (Stq), the speed of rotation (Ng) of the gas generator with a gas generator speed threshold (Sng), and the speed of rotation (Nr) of the rotor with a rotor speed threshold; and stopping, by the processor, the starting of the engine when simultaneously the torque (Tq) is less than the torque threshold (Stq) as determined by the processor from the processor comparing the torque (Tq) with the torque threshold (Stq), the speed of rotation (Ng) of the gas generator is greater than the gas generator speed threshold (Sng) as determined by the processor from the processor comparing the speed of rotation (Ng) of the gas generator with the gas generator speed threshold (Sng), and the speed of rotation (Nr) of the rotor is lower than the rotor speed threshold as determined by the processor from the processor comparing the speed of rotation (Nr) of the rotor with the rotor speed threshold.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The invention and its advantages appear in greater detail from the context of the following description of embodiments given by way of illustration and with reference to the accompanying figures, in which:

(2) FIG. 1 is a diagram showing an aircraft of the invention; and

(3) FIG. 2 is a diagram explaining the method of the invention.

(4) Elements that are present in more than one of the figures are given the same references in each of them.

DETAILED DESCRIPTION OF THE INVENTION

(5) FIG. 1 shows an aircraft 1 of the invention.

(6) The aircraft 1 includes a rotary wing having at least one rotor 2.

(7) In order to set the rotary wing into rotation, the aircraft 1 has at least one turboshaft engine 5 and a main gearbox 3. The engine 5 then drives the main gearbox 3 via a drive train 10 for transmitting power, the main gearbox 3 than setting the rotor 2 in rotation.

(8) The engine 5 has a gas generator 6. The gas generator 6 is conventionally provided with a compressor 7 associated with a high pressure turbine 8.

(9) The engine 5 also has a free turbine 9. The gas coming from the gas generator 6 serves to set the free turbine 9 into rotation.

(10) Consequently, the drive train 10 for transmitting power includes at least one shaft connecting the free turbine 9 to the main gearbox 3. This drive train 10 for transmitting power also possesses a freewheel 15.

(11) Thus, the drive train 10 has an upstream portion 11 connecting the free turbine 9 to a driving portion of the freewheel 15. The drive train 10 also has a downstream portion 12 connecting a driven portion of the freewheel 15 to the main gearbox 3. Each portion may thus have at least one power transmission shaft.

(12) The aircraft 1 is then provided with a monitor system 20 for monitoring the installation when starting the engine 5.

(13) The monitor system 20 has a first measurement device 40 for determining the torque exerted by the engine 5 on the upstream portion 11. This first measurement device 40 may comprise a torque-meter shaft.

(14) In addition, the monitoring system 20 has a second measurement device 50 for determining the speed of rotation Ng of the gas generator 6, i.e. the speed of rotation of the compressor 7 and/or of the high pressure turbine 8, for example.

(15) This second measurement device 50 may be of conventional type.

(16) In addition, the monitoring system 20 has a third measurement device 60 for determining the speed of rotation Nr of the rotor 2. This speed of rotation of the rotor 2 can be evaluated by measuring for example the speed of rotation of the mast of the rotor, or of a mobile part of main gearbox 3, or of a part of the drive train 10. This third measurement device 60 may be of conventional type.

(17) Under such circumstances, the monitor system 20 has a processor unit 25 communicating with the first measurement device 40, the second measurement device 50 and the third measurement device 60.

(18) The processor unit may comprise a member that executes stored instructions in order to apply the method being implemented. The processor unit may thus possess a processor or the equivalent and a non-volatile memory.

(19) This processor unit may be a FADEC system for controlling the engine. In a variant, the processor unit may be remote and may communicate with any system suitable for stopping the engine in order to be able to transmit an order thereto for stopping the engine.

(20) Under such circumstances, and with reference to FIG. 2, during a measurement step STP1 the following are measured continuously:

(21) the torque Tq exerted on the upstream portion 11 as measured by the first measurement device 40; and

(22) the speed of rotation Ng of the gas generator 6 as measured by the second measurement device 50, and

(23) the speed of rotation Nr of said rotor 2 as measured by the third measurement device 60.

(24) During an evaluation step STP2, the processor unit 25 continuously compares the torque Tq with a torque threshold Stq and compares the speed of rotation Ng of the gas generator 6 with a gas generator speed threshold Sng, and compares the speed of rotation Nr of the rotor 2 with a rotor speed threshold.

(25) During a turn-off step STP3, the processor unit 25 requests stopping of the engine 5 when the following three conditions are satisfied simultaneously:

(26) the torque Tq is less than the torque threshold Stq; and

(27) the speed of rotation Ng of the gas generator 6 is greater than the gas generator speed threshold Sng, and

(28) the speed of rotation Nr of the rotor 2 is lower than the rotor speed threshold.

(29) Naturally, the present invention may be subjected to numerous variations as to its implementation. Although several embodiments are described, it will readily be understood that it is not conceivable to identify exhaustively all possible embodiments. It is naturally possible to envisage replacing any of the means described with equivalent means without going beyond the ambit of the present invention.

(30) In particular, the invention may be performed on an aircraft having a plurality of turboshaft engines.