Overheat detection system

Abstract

An overheat detection system comprising a controller for declaring the overheat, and two wiring connections running along a monitored system and configured to react upon overheat. The controller is configured to determine an electrical status of each wiring connection at least between operative and inoperative, the inoperative status corresponding to an electrical anomaly thereof, and electrically connect or disconnect the wiring connections depending on the electrical status thereof, wherein the declaration of overheat is based on a dynamic reconfiguration of the overheat detection system.

Claims

1. An overheat detection system comprising: a controller configured to declare the overheat, and two wiring connections running the same path along a monitored system, each wiring connection connected in an independent loop with the controller, wherein each wiring connection is configured to react upon overheat on the monitored system, and the controller is configured to: determine an electrical status of each wiring connection, at least between an operative status and an inoperative status, the inoperative status corresponding to an electrical anomaly thereof, electrically connect or disconnect the wiring connections depending on the electrical status thereof, so that: in case the controller determines that both wiring connections are in operative status, both wiring connections are maintained connected, in case the controller determines that only one wiring connection is in inoperative status, the inoperative status wiring connection is disconnected, in case the controller determines that both wiring connections are in inoperative status, both wiring connections are maintained connected, declare an overheat in one of the following cases: when the controller detects that both wiring connections are in operative status and both wiring connections react upon such overheat, when the controller detects that only one wiring connection is in inoperative status and the only one operative wiring connection reacts upon such overheat, when the controller detects that both wiring connections are in inoperative status, and at least one of such inoperative wiring connections reacts upon such overheat.

2. The overheat detection system according to claim 1, wherein each wiring connection is configured to react upon an overheat on the monitored system based on their respective impedances.

3. The overheat detection system according to claim 1, wherein, the overheat produces a predetermined decrease of an impedance of each wiring connection.

4. The overheat detection system according to any of claim 1, wherein the controller is configured to check the electrical status of each wiring connection once each second.

5. The overheat detection system according to claim 1, wherein the controller determines that the wiring connection is in inoperative status only if the corresponding electrical anomaly lasts at least a first predetermined time threshold.

6. The overheat detection system according to claim 1, wherein the electrical status of each wiring connection is checked upon controller power-up in order to determine a baseline electrical status of each wiring connection of either operative or inoperative.

7. The overheat detection system according to claim 6, wherein the controller determines the electrical status of each wiring connection as a baseline only if this status lasts at least a second predetermined time threshold.

8. The overheat detection system according to claim 6, wherein in case the controller determines that both wirings connections are in inoperative status as the baseline electrical status, the controller electrically disconnects both wiring connections, an overheat not being declared.

9. The overheat detection system according to claim 1, wherein the electrical status of each wiring connection is checked before shutting down the controller in order to determine an ending electrical status of each wiring connection as either operative or inoperative.

10. The overheat detection system according to claim 9, wherein the controller is configured to report to a database the ending electrical status of each wiring connection determined before shutting down the controller.

11. The overheat detection system according to claim 1, wherein the monitored system on which the wiring connections are running along is part of a pneumatic air distribution system.

12. The overheat detection system according to claim 11, wherein the pneumatic air distribution system is a system of an aircraft.

13. The overheat detection system according to claim 1, wherein each wiring connection comprises at least one sensing means connected in the same independent loop with the controller, the sensing means comprising a conductor core, a conductor outer sheath, and eutectic salts therebetween.

14. The overheat detection system according to claim 13, wherein an inoperative status of the wiring connection is determined by the controller if the conductor core of at least one of its sensing means comprises at least one electrical anomaly.

15. The overheat detection system according to claim 14, wherein the electrical anomaly is a discontinuity.

16. The overheat detection system according to claim 13, wherein an overheat on the monitored system produces a predetermined decrease on the sensing means impedance, thus creating an electrical path between the conductor core and the conductor outer sheath.

17. A pneumatic air distribution system comprising an overheat detection system according to claim 1.

18. A method for declaring an overheat, wherein the method comprises: providing an overheat detection system according to claim 1, and determining by the controller of the overheat detection system, the electrical status of each wiring connection at least between operative and inoperative, such that: in case the controller determines that only one wiring connection is in inoperative status, the controller electrically disconnects such inoperative wiring connection, or in case the controller determines that both wiring connections are in the same electrical status, both wiring connections remains connected, wherein the method further comprises declaring an overheat in one of the following cases: when both wiring connections are in operative status, and both wiring connections react upon such overheat; when only one wiring connection is in inoperative status, and the only one operative wiring connection reacts upon such overheat; or when both wiring connections are in inoperative status, and at least one of such inoperative wiring connections reacts upon such overheat.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other characteristics and advantages of the invention will become clearly understood in view of the detailed description of the invention which becomes apparent from a preferred embodiment of the invention, given just as an example and not being limited thereto, with reference to the drawings.

(2) FIG. 1 shows a schematic lay-out of an embodiment of the overheat detection system according to the invention.

(3) FIG. 2 shows a particular embodiment of a wiring connection comprising various sensing means connected therein.

(4) FIG. 3a schematically shows the way that a wiring connection reacts upon overheat.

(5) FIGS. 3b-3d show different examples of inoperative electrical statuses of the wiring connection.

(6) FIG. 4 shows a flowchart describing an embodiment of a method for declaring overheat according to the invention.

(7) FIG. 5 shows a schematic view of an aircraft comprising an overheat detection system according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(8) As it will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method, data processing apparatus, or a computer program.

(9) FIG. 1 depicts a schematic embodiment of an overheat detection system (10). As it can be seen, the overheat detection system (10) comprises:

(10) a controller (1), and

(11) two wiring connections (2) running along the same path, and each one being connected in an independent loop with the controller (1). As two wiring connections (2) are considered, this architecture is also known as a ‘double loop’.

(12) The controller (1) is an electronic device electrically connected with both wiring connections (2) in independent loops. In particular, the controller (1) is the so-called Bleed Monitoring Computer (‘BMC’). The main functions of the controller (1) are as follows:

(13) determining the electrical status of each wiring connection (2) at least among operative and inoperative,

(14) electrically connecting/disconnecting the wiring connections (2) depending on their respective electrical status, and

(15) declaring an overheat under some circumstances.

(16) In addition, the two wiring connections (2) run along the same path of a monitored system (10). In particular, the monitored system (10) on which the wiring connections (2) are running along is part of a pneumatic air distribution system (10) of an aircraft. Preferably, these wiring connections (2) cover the areas where overheat detection function is required.

(17) Additionally, as it can be observed in FIG. 1, each wiring connection (2) is sectioned in:

(18) a pair of aircraft harness (4),

(19) a pair of connecting cables (5), and

(20) at least one sensing means. In case more than one sensing element is envisaged, the wiring connection (2) further comprises interconnecting cables (6) coupling a pair of sensing elements therebetween.

(21) Thus, the pair of aircraft harnesses (4) and connecting cables (5) allows extending the system (10) and thus reaching remote areas intended to be monitored.

(22) Preferably, this wiring connection (2) allows overheat detection based on the impedance measurement carried out by the controller (1). This condition will be discussed in more detail addressing FIG. 3.

(23) FIG. 2 depicts a particular embodiment of a wiring connection (2) comprising various sensing means connected therein. As it can be observed, the wiring connection (2) comprises one interconnecting cable (6) for each pair of sensing means, thus mechanically and electrically coupling them. That mechanical and electrical coupling is provided by means of connectors (6.1, 6.2) at the ends of the interconnecting cable (6). Additionally, the connectors are of the type of male (6.2)-female (6.1) connectors allowing secure coupling. Similarly, the sensing means (3) further comprises connectors of the type of male (3.4)-female (3.5) connectors.

(24) These sensing means are connected in series along an acknowledged path of the system (10) to be monitored. Thus, the length and number of both sensing means and interconnecting cables (6) are planned beforehand to better suit the conflict areas on the monitored system (10); those conflict areas having a high risk of undergoing an overheat.

(25) Each sensing means shown in FIG. 2 comprises a conductor core (3.1), a conductor outer sheath (3.3), and eutectic salts (3.2) therebetween. In this sense, although the three components decrease their impedance under the rising of temperature, due to its inherent properties, the eutectic salt (3.2) significantly decreases its impedance when the temperature rises above the triggering point.

(26) It is to be noted that such wiring connection (2) is connected within electronic controller (1) forming an independent loop (the controller is not shown in FIG. 2). In a particular embodiment, such controller (1) is configured to measure the electrical continuity of the wiring connection (2) in order to detect any impedance change caused by overheat.

(27) In the absence of air leakage (that is, in the absence of overheat) the impedance of the wiring connection (2) is higher than upon an overheat taking place.

(28) In particular, even though the impedance of metallic components of the sensing means is small, the impedance of cold eutectic salt (3.2) is high. In the event of overheat, since a section of a particular sensing means is heated, the impedance of its eutectic salt (3.2) within this section is highly reduced, and then puts low impedance between the internal metallic core and the external metallic surface. As a result, this impedance decreasing is measured and detected by the electronic component connected to the wiring connection (2).

(29) FIG. 3a schematically depicts a particular way that a wiring connection (2) reacts upon overheat. In this figure, the wiring connection (2) comprises a sensing means in turn comprising a conductor core (3.1), a conductor outer sheath (3.3), and eutectic salts (3.2) therebetween.

(30) As it was mentioned, an ‘overheat’ event is caused by hot air leakage escaping from a monitored system (10) which impacts on the wiring connection (2). In this scenario, the eutectic salt (3.2) becomes liquid thus creating an electrical path between the conductor core (3.1) and the conductor outer sheath (3.3) of the sensing means. This is mainly caused by a rapid impedance decrease. At the end, the impedance of the wiring connection (2) as a whole is reduced.

(31) A skilled person in the relevant art would recognize that, in the absence of sensing means, a section of the wiring connection impacted by hot air leakage—overheat—will undergoes an appreciable decreasing of impedance, thus allowing the controller (1) to detect it.

(32) For illustrative reasons, the electrical path followed during an overheat is reproduced by arrows in dashed lines.

(33) FIGS. 3b to 3d depict examples of inoperative electrical statuses of the wiring connection (2), in relation with the respective electrical anomaly that provokes it.

(34) FIG. 3b depicts a ‘short electrical status’. Due to vibration or inherent failure, the central wire could establish direct contact with the outer sheath (3.3).

(35) FIG. 3c depicts a single discontinuity, as a ‘single open electrical status’. In this scenario, the central wire impedance is normally higher than a predetermined threshold.

(36) In this case, with the present invention, the overheat detection capacity of that wiring connection (2) is not affected insofar the overheat creates the new electrical path. Preferably, an electrical path is created between the conductor core (3.1) and the conductor outer sheath (3.3) of a sensing means, thus allowing the return of the electrical signal to the controller (1) and closing the loop.

(37) Therefore, even with the existence of a single open, electrical continuity, overheat detection would be ensured as both sides of the electrical wiring are still connected to the controller (1), thus restoring overheat detection capacity.

(38) It is to be noted that, for exemplary reasons, only one wiring connection (2) is shown in FIGS. 3a to 3c. Nevertheless, the system (10) according to the invention envisages two wiring connections (2).

(39) FIG. 3d depicts a multiple electrical discontinuity, as a ‘multiple open electrical status’ in a dual loop architecture (i.e. ‘loop1’ and ‘loop2’). In this scenario, multiple electrical anomalies (i.e., opens) have taken placed at different locations along a particular wiring connection (2) (in this particular case, in ‘loop1’). Therefore, the section between the electrical anomalies (named in FIG. 3d as ‘loss of detection’) would no longer be able to inform the controller about its reaction upon overheat.

(40) As it was briefly discussed in the background of the invention, it is required in conventional solutions that if overheat occurs, both loops have to detect the same in order to be declared by the controller (1). In this situation, since there is a section of the affected loop isolated, this intermediate section between ‘opens’ would no longer inform and therefore the condition that both loops detect it cannot be fulfilled in case such overheat occurs within that intermediate section.

(41) Nevertheless, the present invention solves the above drawback as dynamic reconfiguration for declaring an overheat takes place. With the system (10) according to the invention, even if there are multiple electrical anomalies in a particular wiring connection (2) (i.e. in ‘loop1’), one of the following cases happens:

(42) when the controller (1) determines that only such wiring connection (2) is in inoperative status (with multiple opens, ‘loop1’), the inoperative wiring connection (2) is disconnected, and the overheat is declared when only the operative wiring connection (2) reacts upon such overheat, or,

(43) when the controller (1) determines that both wiring connections (2) are in inoperative status (at least one with multiple opens), both wiring connections (2) are maintained connected, and the overheat is declared when at least one of such inoperative wiring connections (2) reacts upon such overheat.

(44) Therefore, the availability of the overheat declaration capacity is increased by the overheat detection system (10) according to the invention, in comparison with conventional solutions.

(45) FIG. 4 depicts the steps of an embodiment of the method for declaring overheats by an overheat detection system (10) according to the invention. Briefly, the steps of the method are shown as follows:

(46) providing an overheat detection system (10) which comprises:

(47) a controller (1), and

(48) two wiring connections (2) running along the same path, and each one being connected in an independent loop with the controller (1),

(49) determining by the controller (1) the electrical status of each wiring connection (2) at least between operative and inoperative, such that:

(50) in case the controller (1) determines that only one wiring connection (2) is in inoperative status, the controller (1) electrically disconnects such inoperative wiring connection (2), or

(51) in case the controller (1) determines that both wiring connection (2) are in the same electrical status, both wiring connections (2) remain connected,

(52) wherein the method further comprises declaring an overheat in one of the following cases:

(53) when both wiring connections (2) are in operative status, and both wiring connections (2) react upon such overheat;

(54) when only one wiring connection (2) is in inoperative status, and the only one operative wiring connection (2) reacts upon such overheat; or

(55) when both wiring connections (2) are in inoperative status, and at least one of such inoperative wiring connections (2) reacts upon such overheat.

(56) As it was already mentioned, the controller (1) is configured to check continuously the electrical status of each wiring connection (2), and therefore the method further comprises the step of:

(57) checking by the controller (1) the electrical status of each wiring connection (2) once each second.

(58) Thus, in case an electrical anomaly in any wiring connections (2) appears (or disappears), the controller (1) will be informed normally in less than 1 second, and thus the criteria to declare an overheat would be updated according to actual electrical integrity. The same operative status is maintained during two electrical integrity checks (1 sec. spaced) in order to revert the inoperative condition into operative.

(59) In the event an electrical anomaly appears, the controller (1) either based on the continuous checking or by isolated information from the impedance modification, shall determine that inoperative electrical condition. Nevertheless, as eventual (or spurious) electrical anomalies may happen, an additional condition that such anomaly remains at least a predetermined time is imposed in order to determine an inoperative status of such wiring connection (2).

(60) As it can be observed, this method is envisaged to be used on aircraft. Therefore, two main situations take place, in-flight and on-ground.

(61) On the in-flight end, the system (10) is self-managed by a dynamic and adaptive reconfiguration to take into account in-situ electrical integrity of the overheat detection system (10).

(62) It is to be noted that during flight, no alert about the advent of an inoperative electrical status is sent or reported. Instead, this alert is sent only afterwards, this is, upon landing, and once the aircraft is on-ground and engines off.

(63) At on-ground end, the electrical status of each wiring connection (2) is checked to provide of initial conditions in order to readjust the overheat declaration criteria. Preferably, the existence of an electrical anomaly is checked upon controller (1) power-up. As a result, a baseline electrical status of each wiring connection (2) is determined.

(64) For assuring an accurate baseline electrical status, the method states a confirmation time in which such electrical anomaly must remain, in order to determine an electrical wiring connection (2) as inoperative. Preferably, this confirmation time takes some seconds.

(65) As it will be observed, the controller (1) of the overheat detection system (10) is the so-called Bleed Monitoring Computer or ‘BMC’. Therefore, the initial checking to establish the baseline electrical status is performer under an ‘electronic build-in test’ (‘E-BIT’) of the BMC.

(66) According to FIG. 4, in case the controller (1) determines that both wirings connections (2) are in inoperative status as the baseline electrical status, the controller (1) electrically disconnects both wiring connections (2), an overheat not being declared. This is, the overheat detection system (10) is ceased.

(67) Still at on-ground end, the electrical status of each wiring connection (2) is checked before shutting down the controller (1) in order to determine an ending electrical status of each wiring connection (2). Preferably, this is performed upon landing, and once the aircraft engines are shut off. This final check is also performed under an ‘electronic build-in test’ (‘E-BIT’) of the BMC.

(68) At this point, the method further comprises sending an alert in case any wiring connection (2) is inoperative in the ending electrical status. As this ending electrical status is less subject to tainting, the method further comprises reporting to a ‘post-flight report’ such ending electrical status. Preferably, the message introduced is a ‘Class II maintenance message’.

(69) Accordingly, the method further comprises carrying out appropriate maintenance tasks to restore the electrical integrity of the wiring connections (2).

(70) FIG. 5 shows an example of an aircraft comprising an overheat detection system (10) according to the invention.

(71) While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.