Aircraft turbine engine assembly including a passive valve for a bypass fuel / oil heat exchanger

Abstract

The invention relates to an aircraft turbine engine assembly comprising a lubricating oil circuit (1') and a fuel supply device (1), the assembly further comprising a passive bypass valve (20) enabling the bypassing of an exchanger (7) by the oil, the valve (20) comprising a valve body (24) and a piston (26) arranged to move within a sliding space (28) defining a first actuation chamber (40) supplied with oil from the oil circuit (1') and a second actuation chamber (42) supplied with fuel from the device (1), the valve (20) being configured so that, when the pressure differential between the oil pressure in the first actuation chamber (40) and the fuel pressure in the second actuation chamber (42) falls below a predetermined pressure differential value, the piston (26) moves from a normal operating position to an exchanger bypassing position.

Description

Technical Field

[0001] This invention relates to the field of aircraft turbine engines, such as turbojet engines and turboprop engines. More specifically, this invention relates to fuel / oil heat exchangers fitted to such turbine engines. Background Technology

[0002] Aircraft turbine engines are typically equipped with multiple fuel / oil heat exchangers, which allow heat exhaust from the engine, recovered from the oil, to be transferred toward the fuel and then used as a cooling source within the exchanger. The fuel, heated by the oil, is then sent to the turbine engine's combustion chamber, allowing a portion of the transferred heat to be reused to improve combustion efficiency.

[0003] Therefore, one or more fuel / oil heat exchangers can be arranged at the junction between the lubrication oil circuit and the fuel supply device. The lubrication oil circuit includes conventional components such as one or more oil tanks, a lubrication unit including at least one oil pump, an oil filter, one or more housings to be pressurized, etc. Furthermore, the fuel supply device of a turbine engine typically includes a fuel supply circuit for the combustion chamber and a bypass circuit for supplying pressurized fuel, such as hydraulic fluid, to the hydraulic system. In fact, aircraft turbine engines include many adjustable components with variable geometry, such as thrust reversers or variable-pitch stator blades, as well as flaps, air-cooling valves, or clearance regulating valves. To actuate these components, it is common and effective to use hydraulic actuators—that is, any hydraulic system that uses a pressure difference in the actuating fluid to actuate workpieces in mechanical components, thus including hydraulic cylinders and servo valve hydraulic controls. Therefore, the hydraulic fluid actuating these systems can be pressurized fuel from the turbine engine's fuel supply device.

[0004] In most turbocharged engine architectures, the fuel / oil exchanger is positioned to generate a fuel pressure level higher than that of the oil. Therefore, due to the differential pressure observed in the exchanger, its deterioration can lead to fuel leakage towards the lubrication circuit. This leakage condition is commonly referred to as "fuel-in-oil." It constitutes a particularly alarming scenario because it can cause significant damage to the turbocharged engine. The risk lies primarily in the fact that, in the event of a leak, fuel can mix with the oil and reach the engine casing at high temperatures, posing a risk of spontaneous ignition of the fuel, followed by combustion of the oil within the casing.

[0005] In the prior art, several solutions have been proposed to prevent damage that may be caused by an increase in the fluid volume in the oil circuit in the event of a "fuel-in-oil" leak. For example, one of these solutions is known from the document FR3 068 102A1.

[0006] Recently, other technical solutions have been proposed, implementing architectures where the pressure level in the oil circuit is higher than that in conventional oil circuits. Therefore, in the fuel / oil heat exchanger, the oil pressure is higher than the fuel pressure. In these architectures, the only risk is a reverse leakage known as "fuel-in-oil." However, even in the event of a deterioration of this "fuel-in-oil" leakage phenomenon, the impact on the engine remains negligible compared to the risk of a reverse "oil-in-fuel" leakage. Nevertheless, the amount of usable oil in the lubricating oil tank remains limited. If such leakage occurs over a prolonged period and / or at a high flow rate, it can lead to the draining of the tank and thus a significant drop in the pressure level in the oil circuit. This phenomenon can then cause a reversal of the differential pressure between the oil and fuel in the exchanger, and the oil circuit will then again become vulnerable to the critical risk of "oil-in-fuel" leakage.

[0007] To limit the risk of pressure differential reversal between oil and fuel in the exchanger, the amount of oil and the size of the casing to be pressurized in the oil circuit can be increased. However, these solutions have implications for quality. Summary of the Invention

[0008] In order to at least partially address the aforementioned drawbacks, the primary objective of this invention is an aircraft turbine engine assembly comprising a turbine engine lubrication oil circuit and a fuel supply device, wherein the oil circuit and the fuel supply device together have a fuel / oil heat exchanger.

[0009] According to the invention, the assembly further includes a passive bypass valve that allows oil from the lubricating oil circuit to bypass the heat exchanger. The bypass valve includes a valve body and a piston arranged to move in a sliding space formed in the valve body. The sliding space defines, on either side of the piston, a first actuation chamber supplied with oil from the oil circuit and a second actuation chamber supplied with fuel from a fuel supply device. The bypass valve is configured such that when the differential pressure between the oil pressure in the first actuation chamber and the fuel pressure in the second actuation chamber drops below a predetermined differential pressure value, the piston moves from a normal operating position to a bypass position. The normal operating position allows oil from the oil circuit to pass through the valve in the direction of the heat exchanger, while the bypass position prevents the oil from circulating in that direction.

[0010] This invention therefore proposes a simple and reliable solution to address the risk of leakage in fuel / oil heat exchangers of aircraft turbine engines. In particular, the reliability stems from the passive nature of the exchanger's bypass valve, as its piston forms an actuating element directly and hydraulically controlled by oil and fuel pressure.

[0011] For the design of the bypass valve, a predetermined differential pressure value between the oil and fuel is determined such that an abnormal pressure drop in the oil relative to the fuel pressure drop can be communicated, and preferably, the pressure difference is communicated in the opposite direction between the oil and fuel. This situation does indeed have the potential to create a "fuel-in-oil" leak in the exchanger, but it is advantageous to prevent this leak by immediately actuating the piston in its bypass position, thereby allowing the oil to bypass the exchanger and thus preventing its risk of contamination by fuel.

[0012] Finally, it should be noted that, by connecting to an architecture that ensures an oil pressure higher than the fuel pressure in the exchanger, the bypass valve implemented in this invention makes it possible to overcome the size constraints of the engine's oil pan without the same risk of "fuel-in-oil" leakage. Advantageously, this results in increased safety without negatively impacting the quality of the components.

[0013] Furthermore, the present invention has at least one of the following optional features, considered individually or in combination.

[0014] Preferably, the bypass valve further includes a resilient return mechanism, preferably a compression spring, that forces the piston toward its bypass position. The force generated on the piston by this resilient return mechanism is thus added to the force generated by the pressure difference between the oil and fuel. In particular, its presence allows for movement of the piston in its bypass position at the moment when the oil pressure remains slightly higher than the fuel pressure, or even before that pressure equalization occurs between the oil and fuel. This resilient return mechanism can also be used to compensate for any pressure loss, particularly in the exchanger. It more generally constitutes an additional degree of freedom in the design of the component due to the possibility of freely determining its calibration.

[0015] Preferably, the bypass valve is a spool-piston valve. However, other valve designs are possible without departing from the scope of the invention.

[0016] Preferably, the bypass valve includes:

[0017] - A sliding piston, comprising a first annular oil passage and a second annular oil passage that are axially separated from each other;

[0018] - The first oil inlet and the first oil outlet, each of the first oil inlet and the first oil outlet has a sliding space leading to the valve body. When the piston is in its normal operating position, the first oil inlet and the first oil outlet are connected to each other through the first annular oil passage. The first oil outlet is connected to the inlet of the heat exchanger.

[0019] - The second oil inlet and the second oil outlet, each of the second oil inlet and the second oil outlet has a sliding space leading to the valve body. When the piston is in its normal operating position, the second oil inlet and the second oil outlet are connected to each other through the second annular oil passage. The second oil inlet is connected to the oil outlet of the heat exchanger.

[0020] And in the bypass position of the sliding piston, it:

[0021] -The connection between the first oil inlet and the first oil outlet is prohibited;

[0022] -Prohibit the connection between the second oil inlet and the second oil outlet;

[0023] - Ensure the connection between the first oil inlet and the second oil outlet through the first annular oil passage or the second annular oil passage.

[0024] Preferably, the bypass valve further includes a third oil inlet leading to the first actuation chamber and a fuel inlet leading to the second actuation chamber.

[0025] Preferably, the third oil inlet leading to the first actuation chamber is connected to the second oil outlet, or to the first oil inlet.

[0026] Preferably, the fuel inlet leading to the second actuation chamber is connected to the fuel inlet of the heat exchanger, or to the fuel outlet of the same heat exchanger.

[0027] Preferably, the bypass valve includes a position sensor of its piston in the sliding space of the valve body.

[0028] Preferably, the lubricating oil circuit includes at least one housing to be lubricated, preferably the rolling bearing housing and / or oil housing of the auxiliary gearbox.

[0029] Finally, another object of the present invention is an aircraft turbine engine including such a component, the turbine engine preferably being a turbojet engine.

[0030] Other advantages and features of the invention will appear in the following non-limiting detailed description. Attached Figure Description

[0031] This description will be given with reference to the accompanying drawings, in which:

[0032] Figure 1 shows a schematic side view of a turbojet engine according to the present invention;

[0033] Figure 2 shows a schematic diagram of the components according to a preferred embodiment of the present invention, assembled with the turbojet engine shown in the above figure;

[0034] Figure 3 is a more detailed view of the heat exchanger and its bypass valve, with the components shown in Figure 2 assembled, and shows the valve piston in the normal operating position.

[0035] Figure 4 is a view similar to Figure 3, in which the piston of the bypass valve occupies the bypass position;

[0036] Figure 5 is a schematic diagram of the exchanger, showing a fuel branch connection different from that of the embodiments in Figures 2 to 4; and

[0037] Figure 6 is a schematic diagram of a bypass valve, showing an oil branch connection that differs from the oil branch connections of the embodiments shown in Figures 2 to 4. Detailed Implementation

[0038] Referring to Figure 1, a dual-flow, twin-body turbojet engine 100 is shown. The turbojet engine 100 typically includes a gas generator 102 with a low-pressure compressor 104 and a low-pressure turbine 112 disposed on either side thereof. The gas generator 102 includes a high-pressure compressor 106, a combustion chamber 108, and a high-pressure turbine 110. In the following text, the terms "front" and "rear" are considered to be in a direction 114 opposite to the main flow direction of the gas within the turbojet engine, which is parallel to the longitudinal axis 103 of the turbojet engine.

[0039] The low-pressure compressor 104 and the low-pressure turbine 112 form a low-pressure body and are connected to each other via a low-pressure shaft 111 centered on axis 103. Similarly, the high-pressure compressor 106 and the high-pressure turbine 110 form a high-pressure body and are connected to each other via a high-pressure shaft 113 centered on axis 103 and arranged around the low-pressure shaft 111. These shafts are supported by roller bearings 119, which are lubricated by means of pressurized oil housings (not labeled in Figure 1). The same applies to the fan hub 117, which is also supported by roller bearings 119 arranged in one or more pressurized oil housings.

[0040] Furthermore, the turbojet engine 100 includes a fan 115 at the front of the gas generator 102 and the low-pressure compressor 104, which is positioned directly behind the engine's intake cone. The fan 115 is rotatable about axis 103 and is surrounded by a fan housing 109. This fan is preferably driven indirectly by the low-pressure shaft 111 via a reduction gear 120, which allows for rotation at a lower speed.

[0041] Furthermore, the turbojet engine 100 is defined as a main flow path 116 through which the main flow passes, and a secondary flow path 118 through which a secondary flow located radially outside the main flow passes.

[0042] Figure 2 shows the assembly 200 of the turbojet engine shown in the figure above. It includes two subassemblies, namely the fuel supply device 1 of the turbojet engine and the lubricating oil circuit 1'.

[0043] Regarding device 1, it is dedicated to supplying fuel to combustion chamber 108, and the hydraulic system 3, such as hydraulic cylinders and servo valve hydraulic control, is dedicated to controlling the variable geometry of the aforementioned type. Device 1 includes a fuel supply circuit 2 for combustion chamber 108. A low-pressure pump 5, a fuel / oil heat exchanger 7, a main fuel filter 9, a high-pressure pump 11, a control valve 10, and a fuel metering unit 12 are installed in series along the fuel circulation direction on this supply circuit 2. Downstream of the metering unit 12, circuit 2 leads to an injector 14 in combustion chamber 108.

[0044] The low-pressure pump 5 and the high-pressure pump 11 can be actuated via a shared shaft, preferably a high-pressure shaft 113, and preferably via an auxiliary gearbox 16 (referred to as "AGB") of a turbine engine. Therefore, the high-pressure pump 11 can be, for example, a piston pump with gears. The low-pressure pump 5 itself can be a power pump, particularly a centrifugal pump.

[0045] The heat exchanger 7 allows for the cooling of the oil in circuit 1', which will be described below, while the filter 9 allows for the prevention of impurities that could potentially damage and / or clog the fuel metering unit 12 or the injectors 14. The fuel metering unit 12, in a known manner, measures the flow rate of fuel supplied to the injectors 4 in the combustion chamber 108.

[0046] The supply device 1 also includes a fuel recovery circuit 15 connecting the fuel metering unit 12 to the supply circuit 2, preferably between the low-pressure pump 5 and the heat exchanger 7. Therefore, excess fuel flow supplied to the fuel metering unit 12 can be returned upstream of the heat exchanger 7 via this recovery circuit 15. A control valve 10 or regulator allows fuel flow to be distributed between the combustion chamber 108 and the hydraulic system 3.

[0047] Lubricating oil circuit 1' is shown only partially because some components have been intentionally removed for clarity. Besides the heat exchanger 7, which also belongs to lubricating oil circuit 1', the lubricating oil circuit includes an oil tank 17 and at least one pressure chamber 18 to be lubricated, such as the roller bearing housing or oil housing of the auxiliary gearbox 16. Other components of oil circuit 1', not shown, are conventional, such as oil pressure valves, oil filters, etc.

[0048] An oil supply pump 25, also known as a main oil pump, is provided between the oil tank 17 and the housing 18 to be lubricated, preferably positioned upstream of the bypass valve 20, which will be described below. Furthermore, one or more oil recovery pumps 27 allow oil recovered in the housing 18 to be returned towards the oil tank 17.

[0049] As described above, the fuel / oil heat exchanger 7 allows the engine's hot exhaust gases, recovered from the oil, exiting the housing 18 to be directed toward the fuel, which serves as a cooling source. Furthermore, the oil-heated fuel is then fed into the combustion chamber 108, which improves combustion efficiency.

[0050] Component 200 also includes a bypass valve 20, which is preferably integrated into the oil circuit 1' by association with the exchanger 7. The bypass valve 20 effectively allows the oil in the circuit 1' to circulate through the circuit 1' under certain operating conditions, which will be detailed below, without passing through the exchanger 7, i.e., by bypassing the exchanger.

[0051] The bypass valve 20 is passive because it is hydraulically controlled by the oil in circuit 1' and the fuel in device 1. For this purpose, branch lines 22 and 23 make it possible to divert a portion of the oil and fuel toward valve 20 to ensure its control, as will now be explained with reference to Figure 3.

[0052] Figure 3 schematically illustrates a bypass valve 20 according to a preferred embodiment of the invention. The valve 20 includes a valve body 24, in which a sliding piston 26 is passively controlled by the pressure of fuel in the supply circuit 2 of the device 1 and the oil pressure in circuit 1'. The sliding piston 26 is movably accommodated in a cylindrical sliding space 28 formed within the valve body 24. The piston 26 has a first solid end 30 axially opposed to a second solid end 32. An intermediate solid portion 34 is provided between these two ends 30, 32, separating a first annular oil passage 36 from a second annular oil passage 38. More specifically, the first oil passage 36 takes the form of an annular groove formed on the outer surface of the sliding piston 26 and axially defined by the first end 30 and the intermediate solid portion 34. Similarly, the second oil passage 38 also takes the form of an annular groove formed on the outer surface of the sliding piston 26 and axially defined by the intermediate solid portion 34 and the second end 32 of the piston.

[0053] In the sliding space 28, the valve body 24 and the first end 30 of the piston define a first actuation oil chamber 40. Conversely, still in the sliding space 28, the valve body 24 and the second end 32 of the piston define a second actuation chamber 42 supplied with fuel. Due to this design, the piston 26 is thus subjected to a pressure difference between the oil and the fuel, which exerts forces on the first and second opposite ends 30, 32 of the piston, respectively. Under this pressure difference, a mechanical force is preferably added by a compression spring 44, one end of which presses against the bottom of the valve body 24, and the opposite end of which presses against the second end 32 of the piston, so as to push the piston in the direction of the first oil actuation chamber 40.

[0054] Multiple hydraulic inlets and outlets lead to the sliding space 28 of the piston 26.

[0055] First, this involves a first oil inlet 48a and a first oil outlet 50a. The first oil inlet 48a is connected to the oil circuit 1', for example, downstream of the housing to be lubricated, so that oil from this housing can be supplied. The first oil outlet 50a is connected via a pipe 52 to an inlet 54 provided on the oil circuit 56 of the exchanger 7.

[0056] This then involves a second oil inlet 48b and a second oil outlet 50b, both axially offset from the first oil inlet 48a and the first oil outlet 50a. The second oil outlet 48b is connected via a pipe 58 to an oil drain port 60 provided on the oil circuit 56 of the exchanger 7. The second oil outlet 50b is connected, in itself, to the circuit 1' in such a way that it can, for example, return oil in the direction of the housing 18.

[0057] Finally, the bypass valve also includes a third inlet 48c leading to the first oil actuation chamber 40 and a fuel inlet 62 leading to the second fuel actuation chamber 42. The third inlet 48c is connected to an oil branch pipe 23 for supplying oil from the second outlet 50b, which is located near and downstream of the second outlet. The fuel inlet 62 is connected, in itself, to a fuel branch pipe 22, the opposite end of which is connected to the vicinity and upstream of a fuel inlet 64, which is located on the fuel circuit 66 of the exchanger 7. In this respect, it should be noted that the circuit 66 terminates at a fuel discharge port 68, which sends heated oil back to the filter 9 of the supply circuit 2.

[0058] In Figure 3, the sliding piston 26 is positioned in the normal operating position, where the oil pressure at the outlet of valve 20 is significantly higher than the fuel pressure at the inlet of exchanger 7. This results in a significantly higher hydraulic pressure in the first actuation chamber 40 than in the second actuation chamber 42, to the point that the pressure difference observed across the sliding piston 26 is sufficient to fully compress the spring 44. In this normal operating position, the piston 26 is therefore abutted against or close to the bottom of the sliding space 28, against which the spring 44 presses, thus reducing the volume of the second fuel actuation chamber 42 to zero or a small value.

[0059] During normal operation of component 200, the oil pressure in circuit 1' is thus significantly higher than the fuel pressure in supply device 1, eliminating the risk of "fuel in oil" leakage in the event of a failure in exchanger 7. This is due to the differential pressure applied to the sliding piston 26, which is pressed into the bottom of sliding space 28 in its normal operating position. In this position, the first inlet 48a and the first outlet 50a are each radially opposite to the first annular oil passage 36 to which they lead, allowing them to communicate with each other. Furthermore, the second inlet 48b and the second outlet 50b are also each radially opposite to the second annular oil passage 38 to which they lead, allowing them to communicate with each other.

[0060] Therefore, oil from circuit 1' seeps into valve 20 via first outlet 48a, then through first annular oil passage 36, and is withdrawn from valve via first outlet 50a. The oil is then reintroduced into inlet 54 of oil circuit 56 of exchanger 7, where it undergoes heat exchange with fuel circulating through fuel circuit 66 of the same exchanger. At the outlet of the exchanger, oil is reintroduced into second inlet 48b of valve 20 via drain port 60 and pipe 58. It then circulates through second annular oil passage 38 to be withdrawn from valve via second outlet 50b, from which oil is reintroduced into the downstream portion of lubricating oil circuit 1'.

[0061] The bypass valve 20 is configured such that when the hydraulic differential on the piston 26 drops below a predetermined differential value, the piston 26 moves from the normal operating position (as shown in Figure 3) that allows oil in the circuit 1' to pass through the exchanger 7 in the direction of the valve 20 to the bypass position shown in Figure 4, thereby preventing the circulation of the oil in the direction of the exchanger 7.

[0062] Figure 4 thus shows the bypass position of the sliding piston 26, which occupies this position after movement caused by a combination of the spring 44 and a reduced pressure differential applied to the opposite end of the piston. In this position, the piston 26 is pressed against the end opposite the sliding space 28, with the spring 44 relaxed. This movement of the piston 26 also results in a change in the relative positions of the inlet and outlet ports 48a, 48b, 50a, 50b on the one hand, and the annular passages 36, 38 on the other. Therefore, this bypass position prohibits communication between the first inlet and outlet ports 48a, 50a, and also prohibits communication between the second inlet and outlet ports 48b, 50b. On the other hand, the first inlet port 48a and the second outlet port 50b are both radially opposite the second annular passage 38 to which they lead, allowing them to communicate with each other and resulting in the desired bypass of the exchanger 7.

[0063] The predetermined differential pressure value that causes this positional change of piston 26 is preferably determined to result in an abnormal oil pressure drop compared to the fuel pressure. It should be noted that the oil pressure drop can occur after a failure of exchanger 7, leading to a "fuel-in-oil" leak. This leak is not critical as long as it does not reverse within exchanger 7, as a reverse "fuel-in-oil" leak is considered more serious and dangerous for turbojet engines. Therefore, the predetermined differential pressure value is preferably determined to be zero or approximately zero, i.e., at or near the moment when this pressure difference between oil and fuel changes sign. In this case, the combination of the pressure difference and the mechanical force generated by the spring does indeed cause piston 26 to move toward its bypass position.

[0064] Because of the possibility that the exchanger 7 is isolated just before or at the moment the fuel pressure equalizes with the oil pressure, the risk of "fuel-in-oil" leakage in the exchanger is advantageously controlled. In this regard, it is worth noting that the presence of spring 44 and the possibility of freely determining its calibration in the first place advantageously make it possible to passively switch valve 20 at the desired moment. If this moment preferably coincides with the condition of oil and fuel pressure equilibrium, or a similar condition, the spring calibration can alternatively be determined to induce valve 20 to switch at the instant when the oil still has a pressure significantly higher than the fuel pressure in at least a portion of the exchanger.

[0065] Therefore, when a predetermined pressure differential is observed on piston 26, this immediately causes piston 26 to move to its bypass position, allowing oil to bypass exchanger 7 and thus preventing the risk of it being contaminated by fuel.

[0066] From the moment the passive valve 20 switches, the pilot is informed of the valve's status and then has a given reaction time, such as approximately 5 minutes, to decide whether to revert to the type of engine slowing and / or stopping throughout the flight. This information can be transmitted to the pilot via a sensor 70 located in the sliding space 28 of the valve 20, indicating the position of the piston 26.

[0067] The oil and fuel branch connections described above can be different. For example, fuel branch pipe 22 can be connected near or downstream of fuel outlet 68, as shown in Figure 5. Similarly, oil branch pipe 23 can be connected near or upstream of the first oil inlet 48a, as schematically shown in Figure 6. Of course, all these alternatives can be combined.

[0068] Those skilled in the art can make other modifications to the invention described only by way of non-limiting embodiments, the scope of which is defined by the appended claims.

Claims

1. An aircraft turbine engine assembly (200) including a turbine engine lubrication oil circuit (1') and a fuel supply device (1), wherein the lubrication oil circuit (1') and the fuel supply device (1) together have a fuel / oil heat exchanger (7). - It is characterized by, The assembly also includes a passive bypass valve (20) that allows oil from the lubricating oil circuit (1') to bypass the fuel / oil heat exchanger (7). The bypass valve (20) includes a valve body (24) and a piston (26) arranged to move in a sliding space (28) formed in the valve body. The sliding space (28) defines a first actuation chamber (40) and a second actuation chamber (42) on either side of the piston (26). The first actuation chamber (40) is supplied with oil from the lubricating oil circuit (1'), and the second actuation chamber... (42) Fuel is supplied from the fuel supply device (1), and the bypass valve (20) is configured such that when the pressure difference between the oil pressure in the first actuation chamber (40) and the fuel pressure in the second actuation chamber (42) drops below a predetermined pressure difference value, the piston (26) moves from the normal operating position to the bypass position, the normal operating position allowing oil from the lubricating oil circuit (1') to pass through the valve (20) in the direction of the fuel / oil heat exchanger (7), and the bypass position prohibiting the circulation of oil from the lubricating oil circuit (1') in the direction of the heat exchanger.

2. The component according to claim 1, characterized in that, The bypass valve (20) also includes an elastic return mechanism that forces the piston (26) toward the bypass position of the piston. The elastic return mechanism is a compression spring (44).

3. The component according to claim 1 or 2, characterized in that, The bypass valve (20) is a spool piston valve.

4. The component according to claim 3, characterized in that, The bypass valve (20) includes: - The sliding piston (26) includes a first annular oil passage (36) and a second annular oil passage (38) that are axially separated from each other. - A first oil inlet (48a) and a first oil outlet (50a), each of the first oil inlet (48a) and the first oil outlet (50a) leading to a sliding space (28) of the valve body, wherein when the piston (26) is in its normal operating position, the first oil inlet (48a) and the first oil outlet (50a) are connected to each other through a first annular oil passage (36), and the first oil outlet (50a) is connected to the oil inlet (54) of the fuel / oil heat exchanger (7); - A second oil inlet (48b) and a second oil outlet (50b), each of the second oil inlet (48b) and the second oil outlet (50b) leading to a sliding space (28) of the valve body, wherein when the piston (26) is in its normal operating position, the second oil inlet (48b) and the second oil outlet (50b) are connected to each other through a second annular oil passage (38), and the second oil inlet (48b) is connected to the oil outlet (60) of the fuel / oil heat exchanger (7); And it is characterized in that, in the bypass position of the sliding piston (26), the sliding piston: - Communication between the first oil inlet (48a) and the first oil outlet (50a) is prohibited; - Communication between the second oil inlet (48b) and the second oil outlet (50b) is prohibited; - Ensure the connection between the first oil inlet (48a) and the second oil outlet (50b) through the first annular oil passage or the second annular oil passage (36, 38).

5. The component according to claim 1, characterized in that, The bypass valve (20) also includes a third oil inlet (48c) leading to the first actuation chamber (40) and a fuel inlet (62) leading to the second actuation chamber (42).

6. The component according to claim 5, characterized in that, The third oil inlet (48c) leading to the first actuation chamber (40) is connected to the second oil outlet (50b) or to the first oil inlet (48a).

7. The component according to claim 5 or 6, characterized in that, The fuel inlet (62) leading to the second actuation chamber (42) is connected to the fuel inlet (64) of the fuel / oil heat exchanger (7), or to the fuel outlet (68) of the same exchanger.

8. The component according to claim 1, characterized in that, The bypass valve (20) includes a position sensor (70) for its piston (26) in the sliding space (28) of the valve body.

9. The component according to claim 1, characterized in that, The lubrication circuit (1') includes at least one housing (18) to be lubricated, which is the rolling bearing housing and / or oil housing of the auxiliary gearbox.

10. An aircraft turbine engine (100) comprising a component (200) according to any one of claims 1 to 9, wherein the turbine engine is a turbojet engine.

Images