Fuel transfer equipment and auxiliary power unit fuel system

Abstract

A fuel transfer device and an auxiliary power unit fuel system equipped with the fuel transfer device are disclosed. The fuel transfer device is connected between a main fuel line and an auxiliary fuel line, and includes: a housing, which is formed as a sealed housing, having a peripheral wall portion, a first base plate near the upstream side of the fuel flow path, and a second base plate near the downstream side of the fuel flow path; a main fuel line, which is disposed between the peripheral wall portion of the housing and the main fuel line; an auxiliary fuel line, which is disposed between the peripheral wall portion of the housing and the auxiliary fuel line; a one-way valve, which is disposed in the auxiliary fuel line, allowing fuel in the auxiliary fuel line to flow to the housing; and a fuel replenishment mechanism, which is disposed in the main fuel line, and replenishes the main fuel line with fuel supplied from the auxiliary fuel line to the housing via the one-way valve when the pressure in the main fuel line drops due to the opening of the auxiliary fuel line. This improves fuel pressure fluctuations in the main fuel line during the starting process of the auxiliary power unit, thereby increasing starting reliability.

Description

Technical Field

[0001] This invention relates to a fuel transfer device and an auxiliary power unit fuel system equipped with the fuel transfer device. Background Technology

[0002] During the initial startup phase of the aircraft's auxiliary power unit (APU), the fuel distribution valve is closed, and fuel is supplied by the main fuel line. When the fuel supply pressure reaches the opening pressure of the distribution valve, the distribution valve opens, and both the main fuel line and the auxiliary fuel line supply fuel simultaneously. However, when the distribution valve opens, the auxiliary fuel line initially has no fuel and requires a certain amount of time to build up fuel pressure. Simultaneously, the main fuel line experiences a momentary pressure drop due to the fuel supply from the auxiliary fuel line. This results in a decrease in fuel supply pressure and flow rate, reduced atomization, and potentially engine stall, leading to startup failure and affecting startup reliability.

[0003] As mentioned above, the existing APU fuel system piping design only has one fuel distribution valve controlling the fuel supply to the main fuel line and the auxiliary fuel line. When the auxiliary fuel line is opened, it can easily cause a sudden drop in fuel pressure in the main fuel line, affecting the fuel supply and atomization effect. In addition, an empty circuit in the auxiliary fuel manifold before starting can easily cause APU start-up failure, especially under the harsh conditions of high-altitude starting.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: CN108561232A

[0007] Patent Document 2: CN116044576A

[0008] Patent Document 3: US10563588B2 Summary of the Invention

[0009] The present invention is made to solve the above-mentioned technical problems, and its purpose is to provide a fuel transfer device and an auxiliary power unit fuel system equipped with the fuel transfer device, which can improve fuel pressure fluctuations during APU start-up and improve start-up reliability.

[0010] One aspect of the present invention relates to a fuel transfer device connected between a main fuel line and an auxiliary fuel line, comprising: a housing, the housing being formed as a sealed housing having a peripheral wall portion, a first base plate near the upstream side of the fuel flow path, and a second base plate near the downstream side of the fuel flow path; a main fuel line disposed between the peripheral wall portion of the housing and the main fuel line; an auxiliary fuel line disposed between the peripheral wall portion of the housing and the auxiliary fuel line; a one-way valve disposed in the auxiliary fuel line, allowing fuel in the auxiliary fuel line to flow to the housing; and a fuel replenishment mechanism disposed in the main fuel line, which replenishes the main fuel line with fuel supplied from the auxiliary fuel line to the housing via the one-way valve when the pressure in the main fuel line decreases due to the opening of the auxiliary fuel line.

[0011] According to this fuel transfer device, during the middle of startup, when the pressure in the main fuel line drops below the specified pressure due to the opening of the auxiliary fuel line, the fuel replenishment mechanism can replenish the main fuel line with fuel stored in the housing. This avoids excessive pressure fluctuations in the main fuel line and improves startup reliability.

[0012] In addition, it includes at least one accumulator that separates a fuel delivery chamber in the housing. Fuel in the auxiliary fuel line is supplied to the fuel delivery chamber via the one-way valve and pressurizes the accumulator.

[0013] By installing an accumulator, a fuel delivery chamber can be separated within the housing. Furthermore, when refueling via the fuel replenishment mechanism, the accumulator can assist in replenishing fuel to the main fuel line.

[0014] Ideally, the fuel replenishment mechanism includes a cover, a slider tube, and an elastic member. The cover is formed as a bottomed hollow cylinder and is located inside the fuel delivery chamber opposite to the main fuel pipe. The slider tube has a bottom, a wall portion, and at least one through hole, which penetrates the wall portion. The slider tube is disposed inside the cover and the main fuel pipe in a manner that allows it to slide between the cover and the main fuel pipe. The elastic member is located inside the cover, with one end connected to the bottom of the cover and the other end connected to the bottom of the slider tube. The through hole is positioned such that when the pressure in the main fuel pipe is less than a specified pressure, it can protrude from the cover under the force of the elastic member, thus connecting the fuel delivery chamber to the main fuel pipe.

[0015] According to this structure, by setting up a fuel replenishment mechanism including a cover, a slider pipe and an elastic component, when the pressure in the fuel pipe drops below the specified pressure, the fuel delivery chamber can be connected to the main fuel pipe through the through hole of the slider pipe to perform a fuel replenishment action.

[0016] In addition, the accumulator includes a plate portion and a power storage mechanism, the plate portion being configured to liquid-tightly separate the interior of the housing, and the power storage mechanism being disposed between the plate portion and the housing.

[0017] According to this structure, the interior of the housing is liquid-tightly separated by a plate, thereby forming a fuel transfer chamber. In addition, a accumulator mechanism is used for pressurization. When fuel is replenished to the main fuel line via the fuel replenishment mechanism, the accumulator mechanism extends and pushes the plate to assist in the replenishment of fuel to the main fuel line.

[0018] In addition, the accumulator includes at least one accumulator capsule and a support. The accumulator capsule is fixed inside the housing by the support. The fuel delivery chamber is formed by the accumulator capsule, the support, and the housing. The accumulator capsule is filled with a predetermined amount of inert gas and is elastically deformable.

[0019] Another type of accumulator includes at least one accumulator capsule and a support. The accumulator capsule is filled with a predetermined amount of inert gas and can be elastically deformed. This also allows for pressure accumulation, helping to replenish fuel to the main fuel line.

[0020] Ideally, the fuel transfer device includes two accumulators, one of which is located upstream of the fuel flow path of the housing, and the other is located downstream of the fuel flow path of the housing.

[0021] According to this structure, an accumulator is provided on the upstream and downstream sides of the fuel flow path of the casing, which can evenly and fully replenish the fuel to the main fuel line.

[0022] Furthermore, the accumulator mechanism is a spring. One end of the spring of one accumulator is connected to the plate portion of the accumulator of the other accumulator, and the other end is connected to the second bottom plate on the upstream side of the fuel flow path of the housing. One end of the spring of the other accumulator is connected to the plate portion of the other accumulator, and the other end is connected to the first bottom plate on the downstream side of the fuel flow path of the housing.

[0023] As a power storage mechanism, it uses a spring, which has a simple structure and is easy to install.

[0024] In addition, the fuel delivery device includes two accumulators, one of which is located upstream of the fuel flow path of the housing, and the other is located downstream of the fuel flow path of the housing.

[0025] Ideally, multiple through holes are evenly arranged in the circumferential direction of the cylinder wall.

[0026] By uniformly setting multiple through holes in the circumference of the cylinder wall, a rapid fuel replenishment action can be performed when the pressure in the main fuel line drops due to the opening of the auxiliary fuel line.

[0027] Another aspect of the present invention relates to an auxiliary power unit fuel system, including a fuel transfer device; a main fuel line that forms a main fuel passage for supplying fuel from a fuel module to a fuel injector; and an auxiliary fuel line that forms an auxiliary fuel passage for supplying fuel from the fuel module to the fuel injector, wherein the fuel transfer device is connected between the main fuel line and the auxiliary fuel line.

[0028] The auxiliary power unit fuel system with this structure can prevent a sudden drop in fuel pressure in the main fuel circuit when the auxiliary fuel circuit is opened, thus avoiding impact on fuel supply and atomization. It can also improve fuel pressure fluctuations during APU startup and enhance starting reliability. Attached Figure Description

[0029] Figure 1 This is a diagram showing the piping structure of the fuel system of the auxiliary power unit equipped with the fuel delivery device of the first embodiment of the present invention.

[0030] Figure 2 This is a cross-sectional view showing the structure of the fuel delivery device according to the first embodiment of the present invention.

[0031] Figure 3 The diagram shows the structure of the slider pipe of the fuel transfer device according to the first embodiment of the present invention. (a) is a front view and (b) is a side view.

[0032] Figure 4 This is another cross-sectional view showing the structure of the fuel delivery device according to the first embodiment of the present invention.

[0033] Figure 5 This is another cross-sectional view showing the structure of the fuel delivery device according to the first embodiment of the present invention.

[0034] Figure 6 This is a cross-sectional view showing the structure of the fuel delivery device according to the second embodiment of the present invention.

[0035] Figure 7 This is a flowchart illustrating the operation of the fuel delivery device according to the first embodiment of the present invention.

[0036] (Symbol Explanation)

[0037] 1. Auxiliary power unit fuel system

[0038] 10 fuel modules

[0039] 20 combustion chambers

[0040] 30 fuel injectors

[0041] 40 main fuel line

[0042] 50 auxiliary fuel line

[0043] 60 fuel oil transfer unit

[0044] 61 Fuel Transfer Chamber

[0045] 62 Main fuel line

[0046] 63 Auxiliary fuel line

[0047] 64 casing

[0048] 65 Slider Through-tube

[0049] Bottom of 651 cylinder

[0050] 652 cylinder wall section

[0051] 653 through hole

[0052] 66 check valve

[0053] 67 Elastic Components

[0054] 68 Accumulator

[0055] 681 plate section

[0056] 682 power storage mechanism

[0057] 69 casing

[0058] 691 Zhou wall section

[0059] 692 First Base Plate

[0060] 693 Second Base Plate

[0061] 78 accumulator capsules

[0062] 79 stents Detailed Implementation

[0063] The preferred embodiments of the invention will now be described in detail with reference to the accompanying drawings. In the drawings, the same symbols are used to denote the same components, and repeated descriptions are sometimes omitted. Additionally, in the drawings, dimensions and shapes are sometimes exaggerated to facilitate understanding of the invention. Furthermore, in the following detailed description, directional terms such as "upper," "lower," "inner," "outer," "longitudinal," and "transverse" are used for illustrative purposes and not for limitation.

[0064] (First Implementation)

[0065] First, refer to Figures 1 to 5The structure of the fuel delivery device according to the first embodiment of the present invention will be described.

[0066] Figure 1 This is a diagram showing the piping structure of the fuel system of the auxiliary power unit equipped with the fuel transfer device of the first embodiment of the present invention. (See diagram for example.) Figure 1 As shown, the auxiliary power unit fuel system 1 mainly includes: fuel module 10, combustion chamber 20, fuel injector 30, main fuel pipe 40, auxiliary fuel pipe 50 and fuel delivery device 60.

[0067] Fuel module 10 is used to supply fuel. Fuel supplied from fuel module 10 is delivered to fuel injector 30 via main fuel line 40 and auxiliary fuel line 50, and then burned in combustion chamber 20 through fuel injector 30 to provide power. The fuel flow path is as follows: Figure 1 As shown by the arrow in the image.

[0068] The main fuel line 40 forms the main fuel circuit, and the auxiliary fuel line 50 forms the auxiliary fuel circuit. The fuel transfer device 60 is connected between the main fuel line 40 and the auxiliary fuel line 50.

[0069] Regarding the structure of the fuel delivery device 60, as follows: Figure 2 As shown, it mainly includes a fuel delivery chamber 61, a main fuel pipe 62, an auxiliary fuel pipe 63, a cover 64, a slider pipe 65, a one-way valve 66, an elastic member 67, at least one accumulator 68, and a housing 69.

[0070] The housing 69 is formed as a sealed housing, having a peripheral wall portion 691, a first bottom plate 692 near the upstream side of the fuel flow path, and a second bottom plate 693 near the downstream side of the fuel flow path.

[0071] The main fuel pipe 62 is located between the peripheral wall portion 691 of the housing 69 and the main fuel pipe 40, connecting the fuel delivery chamber 61 located inside the housing 69 with the main fuel pipe 40. The auxiliary fuel pipe 63 is located between the peripheral wall portion 691 of the housing 69 and the auxiliary fuel pipe 50, connecting the fuel delivery chamber 61 located inside the housing 69 with the auxiliary fuel pipe 50.

[0072] The housing 64 is formed as a bottomed hollow cylinder, having a bottom 641 and a wall portion 642. The housing 64 is disposed within the fuel delivery chamber 61, opposite the main fuel pipe 62, via a mounting member (not shown). The opening of the housing 64 is aligned with the opening of the main fuel pipe 62, and the inner diameter of the housing 64 is the same as the inner diameter of the main fuel pipe 62. Furthermore, the opening of the housing 64 is spaced apart from the peripheral wall portion 691 of the housing 69 by a distance S.

[0073] The structure of the slider tube 65 is as follows Figure 3As shown, the slider tube 65 is formed as a bottomed hollow cylinder, having a bottom 651, a wall portion 652, and at least one through hole 653, which penetrates the wall portion 652. The outer diameter of the slider tube 65 is approximately the same as the inner diameter of the slider tube 65 and the inner diameter of the main fuel pipe 62. The slider tube 65 is disposed inside the cover 64 and the main fuel pipe 62 in a manner that allows it to slide between the cover 64 and the main fuel pipe 62. The through hole 653 is positioned such that when the pressure P2 of the main fuel pipe 40 decreases due to the opening of the auxiliary fuel pipe, it protrudes from the cover 64 under the force of the elastic member 67, and communicates with the fuel delivery chamber 61 through the gap S between the opening of the cover 64 and the peripheral wall portion 691 of the housing 69.

[0074] The elastic member 67 is located inside the cover 64, with one end connected to the bottom 641 of the cover 64 and the other end connected to the bottom 651 of the slider tube 65.

[0075] The cover 64, the slider tube 65, and the elastic member 67 together constitute an oil replenishment mechanism.

[0076] Regarding the structure of the accumulator 68, in this embodiment, we will describe an example where one accumulator is installed on the first base plate 692 side and the second base plate 693 side in the housing 69. Since the structures of the accumulators are the same, we will describe the accumulator installed on the second base plate 693 side as an example.

[0077] like Figure 2 As shown, the accumulator 68 includes a plate portion 681 and a accumulator mechanism 682. As an example, the accumulator mechanism is a spring. The plate portion 681 is formed to fluid-tightly separate the interior of the housing 69. The accumulator mechanism 682 is disposed between the plate portion 681 and the second base plate 693 of the housing 69, with one end connected to the plate portion 681 and the other end connected to the second base plate 693 of the housing 69. By providing the accumulator 68, a fuel delivery chamber 61 is separated within the housing 69. During normal operation, fuel flowing in the auxiliary fuel line 50 is replenished into the fuel delivery chamber 61 via a one-way valve 66, pushing the plate portion 681 and compressing the accumulator mechanism 682, thus accumulating pressure. When fuel is replenished to the main fuel line 40 via the fuel replenishment mechanism, the accumulator mechanism 682 extends and pushes the plate portion 681, assisting in the replenishment of fuel to the main fuel line. By providing the accumulator 68, sufficient pressure can be ensured for fuel replenishment when the main fuel line 40 requires replenishment.

[0078] A one-way valve 66 is provided in the auxiliary fuel supply pipe 63, which allows fuel in the auxiliary fuel pipe 50 to flow to the fuel transfer chamber 61 and prevents fuel in the fuel transfer chamber 61 from flowing to the auxiliary fuel pipe 50.

[0079] The operation of the fuel delivery device in this embodiment will now be explained.

[0080] like Figure 7 As shown, during the previous operation, the fuel flowing in the auxiliary fuel line 50 is stored in the fuel transfer chamber 61 through the one-way valve 66. Since fuel also flows in the main fuel line 40 during operation, the elastic member 67 is compressed under the pressure P2 of the main fuel line 40, and the slider tube 65 is pushed into the cover 64. The through hole 653 is sealed by the cover 64, maintaining the state of fuel stored in the fuel transfer chamber 61.

[0081] After the APU stops, since there is no fuel supply to the main fuel line 40, the pressure P2 in the main fuel line 40 drops. The slider pipe 65 is pushed into the main fuel line 62 under the force of the elastic member 67. The position of the slider pipe 65 is as follows: Figure 2 As shown, the through hole 653 is closed by the main fuel pipe 62, but the fuel is still stored in the fuel delivery chamber 61.

[0082] During initial startup, no fuel flows through the auxiliary fuel line 50, but fuel flows through the main fuel line 40. Under the pressure P2 in the main fuel line 40, the elastic member 67 is compressed, and the slider pipe 65 is pushed into the cover 64. The position of the slider pipe 65 is as follows: Figure 4 As shown, the through hole 653 is closed by the cover 64, and the fuel replenished by the previous operation is still stored in the fuel transfer chamber 61.

[0083] During the initial startup phase, when the auxiliary fuel line 50 opens and the pressure P2 of the main fuel line 40 drops to the specified pressure, the slider pipe 65 is pushed towards the main fuel line 62 under the force of the elastic member 67. Under the combined action of the pressure P2 of the main fuel line 40 and the force of the elastic member 67, the position of the slider pipe 65 is as follows: Figure 5 As shown, the through hole 653 is in communication with the fuel delivery chamber 61, allowing fuel stored in the fuel delivery chamber 61 to be supplied to the main fuel line 40 through the through hole 653. Simultaneously, the accumulator mechanism 682 extends and pushes the plate portion 681, assisting in replenishing fuel to the main fuel line 40. This prevents excessive pressure fluctuations in the main fuel line 40 and improves starting reliability.

[0084] After the pressure P2 of the main fuel line 40 rises and stabilizes due to fuel replenishment, the slider pipe 65 is pushed into the cover 64 under the action of the pressure P2 of the main fuel line 40, and the through hole 653 is closed by the cover 64. In addition, the pressure P1 of the fuel transfer chamber 61 decreases due to fuel replenishment, and the one-way valve 66 opens under the action of the pressure P3 of the auxiliary fuel line 50, storing fuel in the fuel transfer chamber 61.

[0085] The above actions are repeated.

[0086] According to the above-described fuel transfer device, fuel flowing in the auxiliary fuel line during the previous operation can be stored in the fuel transfer chamber through a one-way valve. During the middle of startup, when the pressure of the main fuel line drops due to the opening of the auxiliary fuel line, the fuel stored in the fuel transfer chamber can be replenished to the main fuel line through the through hole of the fuel replenishment mechanism.

[0087] In addition, by installing an accumulator, fuel can be replenished to the main fuel line.

[0088] This can prevent excessive pressure fluctuations in the main fuel line, thereby improving starting reliability.

[0089] (Second Implementation)

[0090] In the first embodiment described above, the accumulator was explained as including a plate and a accumulator mechanism, i.e., a spring. In contrast, in the second embodiment, a accumulator capsule is used. The structure, function, and effects of the second embodiment, unless otherwise specified, are the same as those of the first embodiment. The second embodiment will be described focusing on the differences from the first embodiment.

[0091] Figure 6 This is a cross-sectional view showing the structure of the fuel delivery device according to the second embodiment of the present invention. Figure 6 As shown, at least one accumulator capsule 78, serving as an accumulator, is fixed inside the housing 69 by a bracket 79. A fuel delivery chamber 61 is formed by the accumulator capsule 78, the bracket 79, and the housing 69. A predetermined amount of inert gas is filled inside the accumulator capsule 78.

[0092] The accumulator capsule 78 is elastically deformable. When the fuel flowing in the auxiliary fuel line 50 is stored in the fuel transfer chamber 61 through the one-way valve 66, it is compressed and stored. When the fuel stored in the fuel transfer chamber 61 is supplied to the main fuel line 40 through the through hole 653, it expands and helps to replenish the fuel to the main fuel line 40.

[0093] The fuel delivery device according to the second embodiment can achieve substantially the same effect as the first embodiment.

[0094] The embodiments and variations of the present invention have been described above. However, it should be understood that this disclosure is not limited to the above embodiments and structures. This disclosure also includes various variations and modifications within the equivalent scope. In addition, various combinations and methods, and further combinations and methods that include only one element or more or less thereof, also fall within the scope and spirit of this disclosure.

[0095] The dimensions of the fuel delivery chamber, housing, fuel pipe, as well as the dimensions of the slider pipe, the size / shape of the through hole, the arrangement angle of the slider pipe, and the spring force of the accumulator can be determined through testing and adjusted according to the specifications of the APU.

Claims

1. A fuel delivery device, characterized in that, The fuel transfer device (60) is connected between the main fuel line (40) and the auxiliary fuel line (50), and includes: The housing (69) is formed as a sealed housing and has a peripheral wall portion (691), a first bottom plate (692) near the upstream side of the fuel flow path and a second bottom plate (693) near the downstream side of the fuel flow path. Main fuel line (62), the main fuel line is disposed between the peripheral wall of the housing and the main fuel line; Auxiliary fuel supply pipe (63), wherein the auxiliary fuel supply pipe is disposed between the peripheral wall portion of the housing and the auxiliary fuel supply pipe; One-way valve (66), the one-way valve being disposed in the auxiliary fuel line, allowing fuel in the auxiliary fuel line to flow to the housing; and A fuel replenishment mechanism, disposed in the main fuel line, replenishes the main fuel line with fuel supplied from the auxiliary fuel line to the housing via the one-way valve when the pressure in the main fuel line drops due to the opening of the auxiliary fuel line. It also includes at least one accumulator (68) that divides a fuel transfer chamber (61) in the housing, through which fuel in the auxiliary fuel line is supplied to the fuel transfer chamber via the one-way valve and pressurizes the accumulator. The oil replenishment mechanism includes a cover (64), a slider tube (65), and an elastic component (67). The casing is formed as a bottomed hollow cylinder and is located inside the fuel delivery chamber opposite to the main fuel pipe. The slider tube has a bottom (651), a wall portion (652), and at least one through hole (653), the through hole penetrating the wall portion. The slider tube is disposed inside the cover and the main fuel pipe in a manner that allows it to slide between the cover and the main fuel pipe. The elastic member is disposed inside the housing, with one end connected to the bottom (641) of the housing and the other end connected to the bottom of the cylinder of the slider tube. The position of the through hole is configured such that when the pressure in the main fuel pipe is less than a specified pressure, it can be exposed from the cover under the force of the elastic member, thereby connecting the fuel delivery chamber to the main fuel pipe.

2. The fuel delivery device as described in claim 1, characterized in that, The accumulator includes a plate (681) and a power storage mechanism (682). The plate portion is formed to liquid-tightly separate the interior of the housing. The energy storage mechanism is disposed between the plate and the housing.

3. The fuel delivery device as described in claim 1, characterized in that, The accumulator includes at least one accumulator capsule (78) and a support (79). The pressure-accumulating capsule is fixed inside the shell by the bracket. The fuel delivery chamber is formed by the accumulator capsule, the bracket, and the housing. The accumulator capsule is filled with a specified amount of inert gas and is elastically deformable.

4. The fuel delivery device as described in claim 2, characterized in that, The fuel delivery system includes two of the aforementioned accumulators. One of the accumulators is located upstream of the fuel flow path of the housing, and the other accumulator is located downstream of the fuel flow path of the housing.

5. The fuel delivery device as described in claim 4, characterized in that, The energy storage mechanism is a spring. One end of the spring of one of the accumulators is connected to the plate portion of the accumulator, and the other end is connected to the second bottom plate (693) on the upstream side of the fuel flow path of the housing. One end of the spring of the other accumulator is connected to the plate portion of the other accumulator, and the other end is connected to the first bottom plate (692) on the downstream side of the fuel flow path of the housing.

6. The fuel delivery device as described in claim 3, characterized in that, The fuel delivery system includes two of the aforementioned accumulators. One of the accumulators is located upstream of the fuel flow path of the housing, and the other accumulator is located downstream of the fuel flow path of the housing.

7. The fuel delivery device as claimed in claim 1, characterized in that, Multiple through holes are evenly arranged in the circumferential direction of the cylinder wall.

8. A fuel system for an auxiliary power unit, characterized in that, Includes the fuel delivery device according to any one of claims 1 to 7; The main fuel line (40) forms the main fuel circuit, which supplies fuel from the fuel module (10) to the fuel nozzle (30). An auxiliary fuel line (50) forms an auxiliary fuel circuit, supplying fuel from the fuel module to the fuel injector. The fuel transfer device is connected between the main fuel line and the auxiliary fuel line.

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