FR3047041A1 - DEVICE FOR PROTECTING THE OVERSPEED OF AN ENGINE OF AN AIRCRAFT - Google Patents

Abstract

The invention relates to an overspeed protection device for an aircraft engine, said engine comprising a fuel supply system (10), a logic control device (ECA) being further configured to open or close the system ( 10), the protection device comprising: - a first line (LA) configured to supply the logic control device (ECA); a second line (LB) configured to supply the logic control device (ECA); a first monitoring channel (VA) configured to deliver a first command (SVA) according to the speed of the engine and a first lock command (KOA SVA) according to the speed of the engine and a failure of the first lane; monitoring ; a second monitoring channel (VB) configured to deliver a second command (SVB) according to the speed of the engine and a second lock command (KOB. SVB) according to the speed of the engine and a failure of the second channel monitoring ; the first line and / or the second line (LA, LB) for supplying the logic controller (ECA) being configured to power a logic controller (ECA) when the latch command of the one and / or the other of the supply lines (LA, LB) is inactive (KOx.svx = '0') that is to say that one of the monitoring channels has a failure and / or detects an overspeed and / or the control function of the engine speed is active (SVx = '1') that is to say that the engine has an overspeed.

Description

GENERAL TECHNICAL FIELD The invention relates to the regulation of aircraft engines and more particularly concerns their protection against overspeeds.

STATE OF THE ART

In an aircraft engine, an excessive rotational speed of a shaft can have serious consequences, namely, in particular, cause the bursting of rotors disks mounted on the shaft. Also, such an engine is usually equipped with an overspeed protection device that receives information representative of the rotational speed of a motor shaft and controls a cut, a regulation or a limitation of the fuel supply of the engine. when, for example, this speed of rotation exceeds a predetermined threshold or when an acceleration, a function of this speed exceeds a threshold.

The overspeed safety function must be ensured by a control system and its computer integrated within the engine bay. This calculator is bi-channel and is split into two separate boxes around the engine.

However, the engine zone has environmental levels that are relatively more severe than the current calculator locations (for example the locations in the aircraft hold dedicated to the engine control computers).

The electronic overspeed protection must therefore be compatible with such a topology while having the least possible impact on the design of the computer.

PRESENTATION OF THE INVENTION

An object of the invention is to propose a solution which makes it possible to: provide a protection function against overspeeds: sensor architecture, computer and electro-shut-off valve;

Present a simple interface with the computer: use of discrete signals for the transmission of commands;

Impinge in a small way the signals passing between the channels of the computer: the invention has no inter-channel signal dedicated to overspeed protection; Limit the power dissipation of the computer to perform this overspeed protection function: the power circuit is external to the computer. For this purpose, the invention proposes an overspeed protection device for an aircraft engine, said engine comprising a fuel supply system, a logic control device being further configured to open or close the fuel system. the protection device comprising: - a first line configured to supply the logic control device; a second line configured to supply the logic control device; a first monitoring channel configured to deliver a first command depending on the speed of the engine and a first lock command depending on the speed of the engine and a failure of the first monitoring channel; a second monitoring channel configured to deliver a second command depending on the speed of the engine and a second locking command depending on the speed of the engine and a failure of the second monitoring channel; the first line and / or the second power line of the logic controller being configured to power a logic controller whenever the lock command of one and / or the other of the lines of power supply is inactive, that is to say that one of the monitoring channels has a fault or detects an overspeed and that the control function of the engine speed is active that is to say that the engine has an overspeed . The invention is advantageously completed by the following characteristics, taken alone or in any of their technically possible combination: each supply line comprises a voltage source connected in series with the logic control device and a ground, each line of supply comprises, in series, between the voltage source and the logic controller a normally open switch and a normally closed switch, each supply line comprises, in series between the ground and the logic controller a normally open switch, the normally open switches are controlled by the motor speed function control and the normally closed switches by the interlock control, each monitoring channel includes a speed sensor configured to measure a converted motor speed to a first control and a first control respectively. second command presenting: - a state h aut for an overspeed of the engine, for example for a motor speed V motor such that V motor> Vseuill, with Vseuill a threshold characteristic of an overspeed; - A low state otherwise, for example for a motor speed such that 0 <Vmoteur <Vseuill. - Each monitoring channel includes an engine failure detector configured to, if the overspeed protection device has a failure, deliver a discrete signal having a high state if the engine has a failure, a low state otherwise. The invention also relates to an overspeed protection assembly of an aircraft engine, said engine comprising a fuel supply system, the assembly comprising a logic control device configured to open or close the fuel system and a overspeed protection device according to the invention.

And the invention also relates to an aircraft comprising a set of protections according to the invention, wherein the monitoring channels are integrated in one or more computer (s) electronic engine control or in a. or several electronic control gear dedicated to motor protection. Aircraft in which, in a complementary manner, the supply lines are arranged: in a dedicated housing in the airplane zone, preferably in a so-called out-of-fire zone; or in a dedicated housing in the engine zone; or in the electronic box (es) incorporating the monitoring channels.

The advantages of the invention are manifold. The invention makes it possible to protect the engine in an available and safe manner against overspeeds. The use of a discrete and electrical logic makes it possible to simplify the operations of control / control of the computer and this contrary to the current architectures which make use of too many security and redundancies which make the systems very complex. The invention makes it possible to limit the overall complexity of the protection device. The concept architecture also segregates monitoring channels that generate controls and power paths (power lines). This aspect is beneficial to the calculator: its dissipation, its complexity and its cost are diminished.

PRESENTATION OF THE FIGURES Other characteristics, objects and advantages of the invention will emerge from the description which follows, which is purely illustrative and nonlimiting, and which should be read with reference to the appended drawings, in which: FIG. general of a protection device according to the invention; FIG. 2 illustrates a first state of a protection device according to the invention; FIG. 3 illustrates a second state of a protection device according to the invention; FIG. 4 illustrates a third state of a protection device according to the invention; FIGS. 5a to 5c schematically illustrate arrangements of a device according to the invention.

In all the figures, similar elements bear identical references. DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates an overspeed protection device for an engine of an aircraft according to one embodiment of the invention.

Such a device interfaces with an electronic control computer (FADEC) with two separate channels.

The engine (not shown) of the aircraft comprises, for example, a fuel supply line which can be closed or limited by the overspeed protection device. In order to be able to open or close the supply line 10, the motor comprises a logic control device such as an ECA electro-valve. As is known in the art, this electro-valve ECA moves from an "open" state (open supply line) to a "closed" state (closed supply line) only if it is energized.

The overspeed protection device comprises a first power supply line LA of the logic control device ECA; and a second supply line LB of the ECA logic controller.

Thus, the logic control device ECA can be powered according to two separate supply lines LA, LB under certain conditions which will be described later.

One purpose of the protection device is to supply the logic controller ECA in the event of detection of an overspeed of the engine and / or in the event of a failure of the protection device. As such, the protection device comprises a first motor monitoring channel VA configured to deliver a first command SVA function of the engine speed and a first lock command KOA.sv, a function of the engine speed and a failure. of the surveillance channel concerned.

Similarly, the protection device comprises a second monitoring channel VB configured to deliver a second SVB command depending on the speed of the engine and a second lock command KO B. SVB depending on the engine speed and a failure of the engine. the surveillance channel concerned.

It is considered that the lock command is inactive when KOx. SVx = '0' with x = A or B ie the first channel and / or the second channel has detected failure and / or overspeed. Thus, the protection device of a channel is inhibited by an opposite monitoring channel if the latter does not detect overspeed and if it does not go back to failure.

To deliver these commands, each monitoring channel VA, VB comprises on the one hand a fault detector PA, PB of the control / command over-speed protection (sensor, electronics) and on the other hand a speed sensor CA, CB configured to measure an engine speed. A speed sensor is of the reluctance or hall effect sensor type.

Each fault detector PA, PB delivers a discrete signal KOA, KOB which has a high state CIO if the computer or the logic output has a failure, a low state (Ό ') otherwise.

In addition, each fault detector makes it possible to trace one or more logical information (one here) in the event of a proven failure of the control / command system (computer, sensor or logic output).

Each speed sensor CA, CB makes it possible to measure the speed of rotation of the rotating parts of the engine and respectively delivers, each, a speed information which is converted (not detailed) into a first command SVA and a second command SVB presenting: - a active state T under the conditions of overspeed, for example for a motor speed V motor such that V motor> Vseuill, with Vseuill a threshold characteristic of an overspeed; an idle state Ό 'outside the overspeed conditions, for example for a motor speed such that 0 <Vmotor <Vseuill.

Thus, the first line and / or the second line L_A, LB of supply of the logic control device ECA are configured to supply the logic control device ECA as soon as the lock control of one and / or the other of the power lines LA, LB is inactive KOx. SVx = '0' that is to say that one of the monitoring channels has a breakdown or an overspeed and that the control function of the engine speed is active SVx = 'l' ie that the engine has an overspeed.

As illustrated in FIG. 1, each supply line supplies the logic control device ECA between two points common to the two lines.

Each line extends in parallel to the first common point and comprises in series a voltage source + VB, + VA delivering, for example, a voltage of + 28V, a normally open switch 12, 14 (i.e. it is open without any command) a switch 12, 13 normally closed (that is to say it is closed without any command).

Furthermore, each line extends in parallel to the second common point and comprises a ground line GNDA, GNDB and a switch 15,16 normally open.

The switches II, 12,13,14,15,16 are activated (they change state with respect to their state without control or rest) when the lock command is active or an overspeed is detected. Thus, the overspeed protection device is activated in the following cases:

Overspeed detected on both surveillance channels; or

Overspeed detected on the first monitoring channel and failure detected on the second monitoring channel; or

Overspeed detected on the second monitoring channel and failure detected on the first monitoring channel.

It is noted that the serialization at the power source of two switches (switches 12, 15 of the first line and switches 14, 16 of the second line with the same control logic) performing the same logic function allows to protect itself from short-circuit cases that can supply the ECA logic controller.

We can summarize below the activation logic of the protection device under the following equation, where SV is the state of the ECA (Ό 'open, T closed): SV = (SVA + SVB). (SVB (kBB.SVB) + SVB (SVK) j SV = (SVB + SVB). (SVB (KOB + SVB) + SVB (KOA + SV)) SV = (SVB + SVB). (SVA (KOB + SVB) + SVB (KOA + SVA)) SV = SVA.KOB + SVA.SVB + SVB.KOA + SVA.SVB SV = SVA.SVB + SVA.KOB + SVB.KOA The table of truth is this:

FIG. 2 shows a state of the protection device when there is no breakdown and when there is no overspeed.

In this case the detection system is in nominal operating state and no overspeed is detected, the system is in the following state:

The first and second commands depending on the speed SVA and SVB are inactive

The lock commands are active: no failure and no overspeed. All switches are open, the ECA logic controller is not powered, the protection device is thus inactive, the power supply system is open.

FIG. 3 shows a state of the protection device in the event of overspeed and no breakdown.

In this case: the first and second commands depending on the speed SVA and SVB are active, the overspeed detection is ensured on both channels;

The lock commands are inactive: there is no fault and an overspeed is detected (SV = T, KOx.SVx = o).

All switches are closed, the ECA logic controller is powered through the two power lines, so the protection device is active, the power system is closed.

FIG. 4 shows a state of the protection device when a fault is detected (here on the first monitoring channel VA) and there is an overspeed.

Since there is a fault on the first monitoring channel VA, the first control SVA is undetermined, the switches 14 and 15 can be opened or closed (note X in Figure 4).

In that case :

The first KO A. SVA lock command is inactive and the switch controlled by this command is closed II;

The first command SVA function of the speed of the engine is undetermined, the switches controlled by this first command are either open or closed;

There is an overspeed and no failure on the second monitoring channel so the second command SVB function of the speed of the engine is active, the switches controlled by this second command are closed.

Thus, because of having two power supply lines, the failure of a monitoring channel does not affect the protection device that is active here, the logic control device ECA is powered via the second power supply line, the power supply system is closed. The architecture presented above can be arranged in several ways in an aircraft, knowing that the monitoring channels can be integrated: in the electronic engine control computer, or in a computer dedicated to monitoring.

The supply lines can be located in several places:

FIG. 5a describes an installation where the supply lines are arranged in a motor zone

FIG. 5b describes an installation where the supply lines are arranged in the airplane zone (outside the fire zone)

Figure 5c describes an installation where power lines are an integral part of the monitoring channels. This arrangement makes it possible to reduce the sensitivity to lightning or electromagnetic disturbances.

Claims (10)

claims An overspeed protection device of an aircraft engine, said engine comprising a fuel supply system (10), a logic control device (ECA) being further configured to open or close the system (10) of the engine. power supply, the protection device comprising: - a first line (LA) configured to supply the logic control device (ECA); a second line (LB) configured to supply the logic control device (ECA); a first monitoring channel (VA) configured to deliver a first command (SVA) according to the speed of the engine and a first lock command (KOA SVA) according to the speed of the engine and a failure of the first lane; monitoring ; - a second monitoring channel (VB) configured to deliver a second command (SVB) according to the speed of the engine and a second lock command (K0B.SVB) according to the speed of the engine and a failure of the second channel monitoring ; the first line and / or the second line (LA, LB) for supplying the logic controller (ECA) being configured to power a logic controller (ECA) when the latch command of the one and / or the other of the supply lines (LA, LB) is inactive (KOx. SVx = '0'), that is to say that one of the monitoring channels has a breakdown or detects an overspeed and that the control function of the motor speed is active (SVx = 'l') that is to say that the motor has an overspeed. The device of claim 1, wherein each supply line (LA, LB) comprises a voltage source (+ VA, + VB) connected in series with the logic controller (ECA) and a ground (GNDA, GKBD). The device according to claim 2, wherein each supply line (LA, LB) comprises, in series, between the voltage source and the logic controller (ECA) a normally open switch (12, 14) and a normally closed switch (II, 13). 4. The device according to one of claims 2 to 3, wherein each feed line (LA, IB) comprises, in series between the ground (GNDA, GNDB) and the logic control device (ECA) a = normally open switch (15,16). 5. Device according to one of claims 3 to 4, wherein the normally open switches are controlled by the control function of the motor speed and switches normally closed by the lock control. 6. Device according to one of the preceding claims, wherein each monitoring channel (VA, VB) comprises a speed sensor (CA, CB) configured to measure a converted engine speed in a first control (SVA) and a second control (SVB) having: - a high state (T) for an engine overspeed, for example for a motor speed V motor such as V motor> Vseuill, with Vseuill a threshold characteristic of an overspeed; - a low state CO ') if not for example for a motor speed such that 0 <Vmoteur <Vseuill. 7. Device according to one of the preceding claims, wherein each monitoring channel (VA, VB) comprises an engine failure detector configured to, if the overspeed protection device has a failure, deliver a discrete signal (KOA, KOB ) with a high CIO state if the engine has a fault, a COO low state otherwise. An overspeed protection assembly of an aircraft engine, said engine comprising a fuel supply system (10), the assembly comprising a logic control device (ECA) configured to open or close the system (10). power supply and an overspeed protection device according to one of the preceding claims. 9. Aircraft comprising a protection assembly according to claim 8, wherein the monitoring channels are integrated: - in one or more computers) electronic engine control; - in one or more electronic housing (s) dedicated to motor protection. 10. Aircraft according to claim 9, wherein the supply lines are arranged: in a dedicated housing in the aircraft zone, preferably in a so-called out-of-fire zone; - or in a dedicated housing in the engine zone; / - or in the electronic box (es) incorporating the monitoring channels.