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1 V,. v 1 US A1 (19) United States (12) Patent Appl lca tlol Publication (10) Pub. N0.: US 2008/ A1 GALVEL (43) Pub. Date: (54) DEVCE AND METHOD OF STANDBY LUBRFCATON FOR AN ENGNE (75) nventor: Jean Pierre GALVEL, Savigny Le Temple (FR) Correspondence Address: OBLON, SPVAK, MCCLELLAND MAER & NEUSTADT, RC DUKE STREET ALEXANDRA, VA (73) Assignee: (21) Appl.No.: (22) Filed: (30) Feb. 21, 2007 ll WTH L SNECMA 12/033,391 Feb. 19, 2008 Foreign Application Priority Data.:-:ZLJ ~ n.n H w (FR) 2...t v.» u...» \\ l.. 1,. n \ \ ii,". i\\-n'. m.1 H u -, u " T 1. Publication Classi?cation (51) nt. Cl. G06F 19/00 ( ) F01M 11/10 ( ) F01M 1/08 ( ) B60R 17/00 ( ) B64C 39/00 ( ) F02C 7/06 ( ) (52) US. Cl. 184/6.4; 701/114; 184/6.26;184/1.5; 280/29; 244/4 R; 123/196 S; 60/3908 (57) ABSTRACT The invention relates to a standby lubrication method for an engine 1 in the event of the failure of a main lubrication system 2 of this engine 1, in Which said failure is detected and,, PARS (PR) in response to the detection of this failure, at least one portion u. 1 a n. a u. it 3.-i\-. w ~\v " ll..\\ ln l % n - n l?li..) l l of a fuel?uid of the engine 1 is tapped off to lubricate at least one element of the engine 1. The invention also relates to a standby lubrication device 6 for an engine 1 comprising a main lubrication system 2, said standby lubrication device 6 comprising means for detecting a failure of the main lubrica tion system 2, means 12 for tapping off at least a portion of a fuel?uid of the engine 1 in order to direct it to at least one element of the engine 1 intended to be lubricated, and control means 15 capable of being connected to said tapping and detection means 12, in order to carry out the standby lubrica tion method. 4 6 u 4 7. a:. O w.. 2 n u H./ n /#../ v 4 /n u JW )Li a v. 17 n //. 5*. 7 h a?". n H l.l. 5 n. H " w //V/ n - n n -. :::1:::: 1:13:31 Z:X:Z: 12:.ZZ1:1: n H. n 1 J.,. 18

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3 DEVCE AND METHOD OF STANDBY LUBRFCATON FOR AN ENGNE [0001] The present invention relates to a device and method for the standby lubrication of an engine, and more particularly for an engine of the gas turbine type, such as a turboj et. BACKGROUND OF THE NVENTON [0002] Engine is understood to be any device generating movement, preferably by combustion of a fuel?uid, such as, for example, a reciprocating piston engine, a four-stroke or Diesel engine, a rotary piston engine, for example of the Wankel type, a turbine, such as for example a turboprop or turbojet With single or double spool, an electric motor sup plied by a fuel cell, etc. Such engines may be used in the propulsion of a vehicle or for other applications, such as the generation of electric power, the operation of machines, such as, for example, pumps or compressors, etc. DESCRPTON OF THE PROR ART [0003] The engines of the prior art conventionally comprise a lubrication system designed to lubricate and if necessary cool bearings and gears in the engine, the accessory drive gearbox included. [0004] Such a conventional lubrication system usually con sists of a reservoir of lubricant?uid, for example of oil, a feed and return pipe and a lubricant fuel pump to circulate the lubricant from the reservoir to the elements to be lubricated and return to the reservoir through said feed and return pipe. n addition, it is usually a known practice also to include therein a?lter in order to ensure that impurities that may damage the elements to be lubricated are not circulated With the lubricant?uid to these elements to be lubricated, a heat exchanger designed to cool the lubricant?uid, a lubricant?uid diffuser or spray nozzle to distribute the lubricant?uid in said elements to be lubricated and temperature and pressure sensors in order to monitor the operation of the system. [0005] n the event of a failure of the lubrication system, the engine risks being damaged to the point of stopping. The temperature and pressure sensors monitor the correct opera tion of the system and may cause the engine to shut down in order to protect the latter from the harmful effects of opera tion Without oil. [0006] n certain applications, such an inopportune shut down may be particularly dangerous and particular measures are taken to prevent it. For example, in an aircraft comprising a single engine for its propulsion, it is routine to arrange, in addition to the main lubrication system, a standby lubrication device designed to provide the aircraft With additional autonomy making it possible to divert to an air?eld in the event of failure of the main lubrication system. [0007] n the prior art, described for example in American patent US. Pat. No. 4,888,947, such a standby lubrication device comprises an accumulator of oil tapped from the main lubrication system to provide the minimal lubrication required and prolong the operation of the engine for a deter mined period, typically 20 minutes, after a failure of the main lubrication system. This standby lubrication device accord ingly increases the volume of oil of the main lubrication system, and therefore the Weight of the engine, but Without having a use except for a possible failure of the main lubri cation system. n addition, its use is limited in time. [0008] n an aircraft comprising several engines for its pro pulsion, the shutdown of only one of its engines following a failure of its lubrication system is less dangerous, the other engine or engines usually being su?icient to allow a diversion to an air?eld. Nevertheless, a simultaneous failure of all the lubrication systems may lead to the loss of the aircraft. This type of simultaneous failure has already been encountered, particularly following incorrect maintenance actions on the lubrication systems. The use of a standby lubrication device With an oil accumulator, as described above, Would not pre vent the multiple failure, nor the shutdown of the engines after the accumulator oil has been used up, Whereas otherwise the engines may still be in perfect Working order. SUMMARY OF THE NVENTON [0009] The problem of the present invention is therefore to provide an independent standby lubrication for one engine comprising a main oil lubrication system in the event that this lubrication system fails. This standby lubrication must be provided With a minimal Weight penalty, a period of use limited only by the availability of the?uid used, and an easy adaptation to existing engines. [0010] n addition, the present invention must make it pos sible to eliminate the risks associated With the concurrent failure of the lubrication systems in a plurality of engines. All this should result in a considerable increase in the level of safety. DESCRPTON OF THE PREFERRED EMBODMENTS [0011] According to the invention, the failure of the lubri cation system is detected and, in response to the detection of this failure, at least one portion of the fuel?uid of the engine is tapped off to lubricate at least one engine element. [0012] Although lubrication systems have been proposed, for example in US. Pat. No. 5,568,984, to lubricate and if necessary cool an engine With the fuel?uid of the latter, such lubrication systems, Which are used in particular in jet engines used for the propulsion of missiles, are designed to lubricate the engine in a normal situation and not in the event of failure of another lubrication system. On the basis of these publications, it Would not therefore have been evident for those skilled in the art to apply this solution to solve the problem of standby lubrication in the event of failure of a main lubrication system. Furthermore, these systems of lubri cation With a fuel?uid in a normal situation make it possible to ensure only a modest lubrication compared With that obtained With a lubrication system With oil. [0013] Preferably, in the method of the invention, said por tion of engine fuel?uid tapped off for standby lubrication is directed into at least one enclosure in the engine, and said enclosure in the engine is drained in order to prevent an over?lling thereof When the fuel?uid is added to the oil of the main lubrication system in said enclosure. [0014] Preferably, in this method, in response to the detec tion of this failure, the engine is also placed in a safety regime limiting its?eld of operation. This makes it possible to limit the number of engine elements requiring this standby lubri cation in the event of failure of the main lubrication system and therefore also the quantity of fuel?uid employed for this standby lubrication and the means necessary for tapping it off.

4 [0015] The standby lubrication device of the invention comprises means for detecting a failure of the main lubrica tion system, means for tapping off at least a portion of a fuel?uid of the engine in order to direct it to at least one engine element intended to be lubricated, and control means capable of being connected to said detection and tapping means in order to activate said tapping means in response to a failure of the main lubrication system. [0016] Preferably, said detection means comprise at least one oil low-pressure sensor, Which forms a particularly simple means for detecting a failure of the main lubrication system. [0017] n order to better lubricate the elements to be lubri cated, it is preferable for said tapping means to discharge into at least one spray nozzle. f furthermore said spray nozzle comprises at least one spray nozzle of the main lubrication system, it prevents the duplication of elements, resulting in an advantageous Weight gain. [0018] Preferably, said tapping means comprise a tapping pipe With at least a?rst valve. Such a?rst valve has the advantage of making it possible easily to connect and discon nect the standby lubrication device to/from a fuel?uid feed circuit of the engine in order to tap at least a portion thereof. [0019] Preferably, the standby lubrication device also com prises means for draining at least one enclosure in the engine, said control means also being capable of being connected to said drainage means in order to activate said drainage means in response to a failure of the main lubrication system. These drainage means make it possible to prevent over?lling of this enclosure When the fuel?uid is added to the oil of the main lubrication system in said enclosure. [0020] Preferably, said drainage means comprise a drain age pipe With at least a second valve. Such a second valve has the advantage of making it possible easily to drain said enclo sure With a signal from said control means. [0021] Advantageously, said?rst and second valves are functionally connected, so that the tapping of the fuel?uid for lubrication is always associated With the drainage of said enclosures. n this embodiment, preferably, said?rst and second valves are incorporated into a double valve With single control, Which makes it possible to simplify the standby lubri cation device, While ensuring that the tapping of fuel?uid for lubrication is always associated With the drainage of said enclosures. [0022] More particularly, said drainage means comprise at least one discharge duct, opening, for example, into an engine air?ow or else into a Zone distant from the engine, Which makes it possible to drain the oil and the fuel?uid from the enclosure into a Zone presenting no danger. [0023] The invention also relates to an engine comprising a main oil lubrication system and a standby lubrication device according to the invention. n particular, said engine is an engine of the gas turbine type, a type of engine Whose lubri cation needs are particularly great. [0024] The invention also relates to a vehicle comprising an engine according to the invention. Vehicles have a particu larly critical need for engine reliability, and particularly engines providing the propulsion of the vehicles. This need is even more critical in aircraft. BREF DESCRPTON OF THE DRAWNGS [0025] Details concerning the invention are described below making reference to the drawings. [0026] The single FGURE represents schematically an embodiment of the engine of the invention With the main lubrication system and the standby lubrication device. DESCRPTON OF THE PREFERRED EMBODMENTS [0027] The illustrated engine 1 is, for example, an aircraft propulsion element, an application in Which reliability is a priority. t is however conceivable to apply the invention in engines for propelling other types of vehicles, or even for other applications, such as the generation of electric power in an onboard or?xed generator. The illustrated engine 1 is furthermore of the gas turbine type and more particularly a turbojet, but it is also conceivable to apply the invention to other types of engines. [0028] The illustrated engine 1 comprises a main lubrica tion system 2, a feed system 3 for feeding a combustion chamber 4 With a fuel?uid, an enclosure 5 containing ele ments of the engine 1 to be lubricated and cooled, such as bearings and/or gears, and a standby lubrication device 6. [0029] The main lubrication system 2 feeds, in operation, a lubricant?uid to lubricate the elements in the enclosure 5. For this, the main lubrication system 2 comprises a reservoir 7, a feed and return pipe 8 and a pump 9, comprising, in the embodiment illustrated, a feed pump 9a and a return pump 9b. n the illustrated embodiment, the lubricant?uid is oil. [0030] n the normal state of operation of the main lubrica tion system 2, the pump 9 circulates the oil through the pipe 8 from the reservoir 7 to the enclosure 5 and returns it to the reservoir 7. n addition to the elements illustrated, the main lubrication system 2 may also comprise a?lter to ensure that impurities that may damage the elements to be lubricated are not circulated With the lubricant?uid to these elements to be lubricated, a heat exchanger designed to cool the lubricant?uid, a lubricant?uid diffuser or spray nozzle to distribute the lubricant?uid in the enclosure 5 and temperature and pres sure sensors 14 in order to check the pressure and the tem perature of the lubricant?uid, Which makes it possible to detect a malfunction of the circuit and valves in the pipe 8 in order to control the circulation of the lubricant?uid in response to its temperature and pressure. [0031] The feed system 3 comprises in particular a fuel?uid pipe 10 and a fuel?uid pump 11. This feed system 3 is regulated by a system for controlling the operation of the engine 1 and provides a fuel?uid pressure and?ow allowing the operation of the engine 1. [0032] The standby lubrication device 6 comprises fuel?uid tapping means 12, drainage means 13, a low-pressure sensor 14 installed in the pipe 8 of the main lubrication system 2 and control means 15 connected to the low-pressure sensor 14. [0033] The tapping means 12 comprise a tapping pipe 16 connected to the fuel?uid pipe 10 and opening into the enclosure 5, Where necessary into spray nozzles that may be the spray nozzles of the main lubrication system 2 and/or independent spray nozzles, adapted according to the viscosity of the fuel?uid and the pressure and?ow necessary for standby lubrication. The standby lubrication device 6 does not necessarily have to provide fuel?uid to all the elements of the engine 1 that are normally lubricated by the main lubri cation system 2, but may be limited to providing fuel?uid to lubricate the elements of the engine 1 requiring such lubrica tion to prevent a shutdown of the engine 1 running in a safety regime.

5 [0034] The tapping means 12 also comprise, on the tapping pipe 16, a?rst valve 1711 that is electrically or mechanically controlled and connected to control means 15, so as to open or close the fuel?uid?ow through the tapping pipe 16 in response to signals from the control means 15. [0035] The drainage means 13 comprise a drainage pipe 18 connected to the enclosure 5 and opening onto the outside through at least one discharge duct 19. Said discharge duct 19 is situated in a Zone Where the discharge of the lubricant and/ or fuel?uids does not present a danger. For example, in a twin-spool turbojet surrounded by a nacelle, said discharge duct 19 may be situated in the engine air?ow or outside the nacelle, or in a recovery system commonly known as the Ecology box. [0036] The drainage means 13 also comprise a second valve 17b that is electrically or mechanically controlled and connected to the control means 15, so as to open or close the?ow of?uid drained through the drainage pipe 18 in response to signals from the control means 15. [0037] n the embodiment illustrated, the?rst valve 17a and the second valve 17b are incorporated into a double valve 17 With single control controlled by the control means 15. [0038] n the event of failure of the main lubrication system 2, the low-pressure sensor 14 signals the failure to the control means 15. n response to this signal, the control means 15 then command the opening of the double valve 17, so as to tap from the fuel?uid pipe 10 at least a portion of the fuel?uid in order to lubricate the elements of the engine 1 and to drain the enclosure 5 in order to prevent it being over?lled. The drain age Will?rst cause an emptying of a mixture of oil and fuel?uid, then fuel?uid only. [0039] n response to the signal from the low-pressure sen sor 14, the control means may also trigger a pilot alarm 20 and/ or place the engine 1 in a safety regime. n such a safety regime, the speed, the engine torques or forces or the power generated by the engine may for example be limited in order to limit the heating by friction to be taken into account for the dimensioning of the standby lubrication device. This makes it possible to limit the number of elements of the engine 1 to be lubricated by the standby lubrication device 6 in the event of failure of the main lubrication system 2. n this safety regime, and With the standby lubrication With the fuel?uid, an aircraft propelled by the engine 1 Will have a greater margin of maneuver to decide on a diversion to an alternate air?eld. [0040] n another embodiment, the?rst and/ or second valves 17a, 17b may be controlled by an automatic valve system reacting to an abnormal pressure change and repre senting a failure of the main lubrication system, Which makes it possible to dispense With the low-pressure sensor 14 and separate control means 15. [0041] The standby lubrication device 6 being substantially independent of the main lubrication system 2, its dimension ing may be adapted to the necessities of good operation. Apart from the possibility of limiting the number of elements lubri cated by the standby lubrication device 6 according to the limitations of the safety regime and of adaptation of the spray nozzles to the viscosity of the fuel?uid and to the pressure and?ow of the standby lubrication device 6, it is also possible to interpose, in the tapping pipe 16, independent pressure regulation means such as a diaphragm and/or a pressure lim iter. [0042] Although the present invention has been described With reference to speci?c exemplary embodiments, it is evi dent that modi?cations may be made to these examples With out departing from the general scope of the invention as de?ned by the claims. Consequently, the description must be considered to be illustrative rather than descriptive. REFERENCE NUMBERS N THE FGURES [0043] 1 Engine [0044] 2 Main lubrication system [0045] 3 Feed system [0046] 4 Combustion chamber [0047] 5 Enclosure [0048] 6 Standby lubrication device [0049] 7 Reservoir [0050] 8 Pipe [0051] 9 Pump [0052] 9a Feed pump [0053] 9b Return pump [0054] 10 Fuel?uid pipe [0055] 11 Fuel?uid pump [0056] 12 Tapping means [0057] 13 Drainage means [0058] 14 LoW-pressure sensor [0059] 15 Control means [0060] 16 Tapping pipe [0061] 17 Double valve [0062] 1711 First valve [0063] 17b Second valve [0064] 18 Drainage pipe [0065] 19 Discharge duct [0066] 20 Pilot alarm 1. A method for the standby lubrication of an engine in the event of the failure of a main lubrication system of this engine in Which said failure is detected; Wherein, in response to the detection of this failure, at least a portion of a fuel?uid of the engine is tapped off to lubricate at least one engine element. 2. The method as claimed in claim 1, Wherein said portion of the engine fuel?uid is directed into at least one enclosure in the engine and this enclosure is drained in order to prevent any over?lling. 3. The method as claimed in one of claims 1 or 2, Wherein, in response to the detection of this failure, the engine is placed in a safety regime limiting its?eld of operation. 4. A standby lubrication device for an engine comprising a main lubrication system, said standby lubrication device comprising means for detecting a failure of the main lubrica tion system, Which also comprises means for tapping off at least a portion of a fuel?uid of the engine in order to direct it to at least one engine element intended to be lubricated and control means capable of being connected to said tapping and detection means. 5. The standby lubrication device as claimed in claim 4, Wherein said detection means comprise at least one low pressure sensor. 6. The standby lubrication device as claimed in one of claims 4 or 5, Wherein said tapping means discharge into at least one spray nozzle. 7. The standby lubrication device as claimed in claim 6, Wherein said spray nozzle comprises at least one spray nozzle of the main lubrication system (2). 8. The standby lubrication device as claimed in one of claims 4 to 7, Wherein said tapping means comprise a tapping pipe With at least a?rst valve. 9. The standby lubrication device as claimed in one of claims 4 to 8, also comprising means for draining at least one

6 enclosure in the engine, said control means also being capable of being connected to said drainage means. 10. The standby lubrication device as claimed in claim 9, Wherein said drainage means comprise a drainage pipe With at least a second valve. 11. The standby lubrication device as claimed in claims 8 and 10, Wherein said?rst and second valves are functionally connected. 12. The standby lubrication device as claimed in claim 11, Wherein said?rst and second valves are incorporated into a double valve With single control. 13. The standby lubrication device as claimed in one of claims 9 to 12, Wherein said drainage means comprise at least one discharge duct, discharging, for example, into an engine air?ow or else into a Zone distant from the engine. 14. An engine comprising a main lubrication system and a standby lubrication device as claimed in one of claims 4 to The engine as claimed in claim 14, of the gas turbine type. 16. A vehicle comprising at least one lubrication device as claimed in one of claims 4 to An aircraft comprising at least one engine as claimed in one of claims 14 or 15. * * * * *