Emergency oil drainage system and method for four-engine aircraft

Abstract

The invention belongs to the technical field of aircraft fuel systems, and discloses a four-engine aircraft emergency oil drainage system and method.The four-engine aircraft emergency oil drainage system comprises a plurality of oil tanks including the first oil tank and the second oil tank located on one side of an aircraft and the third oil tank and the fourth oil tank located on the other side of the aircraft; each oil tank is divided into an outer compartment, an inner compartment and an oil collecting tank, and an oil tank partition plate one-way valve is arranged at the bottom of a rib plate between the compartments and used for ensuring that fuel oil flows to the inner compartment from the outer compartment and then flows to the oil collecting tank and preventing the fuel oil from reversely flowing; and one emergency oil drain pump is arranged at the lower part of the inner compartment of each oil tank and is used for pumping the fuel oil in the inner compartment and the outer compartment of the oil tank. The system solves the problem that the emergency oil drainage amount is insufficient due to single-point faults of an existing system, and the safety of an airplane can be fully guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of aircraft fuel system technology, specifically relating to an emergency fuel dumping system and method for a four-engine aircraft. Background Technology

[0002] The emergency fuel jettison system is mainly used to ensure that the aircraft can quickly release fuel in the air in the event of an emergency, reduce the aircraft's weight, and ensure that the weight of the aircraft during an emergency landing does not exceed the maximum landing weight. Emergency situations include system failures, sudden illnesses of passengers on board requiring emergency medical transport, etc.

[0003] In situations requiring emergency oil draining, the industry generally employs two methods: designing an independent emergency oil drain pump or borrowing the engine's fuel supply pump.

[0004] The first design method, featuring an independent emergency drain pump, involves installing a separate emergency drain pump for each fuel tank. The start and end of the emergency drain are controlled by manipulating the pump and the drain valve. The advantage of this method is that it allows for arbitrary control of emergency drain from each tank, and the emergency drain system is relatively independent, not affecting engine fuel supply or other systems. However, the disadvantage is that if the emergency drain pump or valve malfunctions, a single point of failure can easily lead to either failure to drain or excessive draining. If not addressed promptly, this can also cause fuel imbalance problems.

[0005] The second method utilizes the engine's fuel supply pump and fuel line. A branch line is added to the fuel line, and the start and end of emergency fuel release are controlled by opening and closing an emergency fuel release valve. The advantage of this method is its relative simplicity, with minimal additional equipment and reduced system weight. The disadvantages are that it requires a high flow rate from the fuel supply pump and necessitates careful consideration of flow matching between emergency fuel release and supply during the design phase. If the fuel supply pump malfunctions during emergency fuel release, both critical systems will fail, resulting in either failure to release fuel or fuel imbalance. Furthermore, a malfunctioning emergency fuel release valve may lead to excessive fuel release. Summary of the Invention

[0006] This invention proposes an emergency fuel dumping system and method for four-engine aircraft. Without significantly increasing the system development cost, it combines a pressure refueling system with an emergency fuel dumping system. Through the design of fuel tank compartments and the arrangement of emergency fuel dumping pumps in the fuel tanks, the problem of excessive emergency fuel dumping is avoided from the system principle. Furthermore, by setting up a separate emergency fuel dumping pump in each fuel tank, the problem of insufficient emergency fuel dumping due to single-point failure is avoided.

[0007] The technical solution of this invention is implemented as follows:

[0008] In a first aspect, the present invention provides an emergency fuel dumping system for a four-engine aircraft, comprising:

[0009] Multiple fuel tanks, including fuel tanks I and II located on one side of the aircraft, and fuel tanks III and IV located on the other side of the aircraft;

[0010] Each of the fuel tanks is divided into an outer compartment, an inner compartment, and a collection tank. A one-way valve for the fuel tank partition is provided at the bottom of the rib between each compartment to ensure that the fuel flows from the outer compartment to the inner compartment and then to the collection tank, and to prevent it from flowing in the opposite direction.

[0011] An emergency fuel drain pump is provided at the bottom of the inner compartment of each fuel tank to pump fuel from the inner and outer compartments of the fuel tank.

[0012] The pressure refueling pipeline is connected to the refueling control valve of each fuel tank;

[0013] An emergency fuel drain line has one end connected to the pressure refueling line and the other end used to drain fuel out of the machine.

[0014] Multiple emergency drain valves are connected in parallel on the emergency drain pipeline;

[0015] The emergency oil drain pumps of oil tanks I and IV are controlled by the first pump control button, and the emergency oil drain pumps of oil tanks II and III are controlled by the second pump control button.

[0016] The emergency drain valves corresponding to oil tanks I and IV are controlled by the first valve control button, and the emergency drain valves corresponding to oil tanks II and III are controlled by the second valve control button.

[0017] As a further technical solution of the present invention: the emergency oil drain valve is divided into two groups connected in parallel on the emergency oil drain pipeline, wherein the first parallel branch includes an emergency oil drain valve that controls the fuel supply and demand of oil tank I and oil tank II, and the second parallel branch includes an emergency oil drain valve that controls the fuel supply and demand of oil tank III and oil tank IV.

[0018] As a further technical solution of the present invention: the two emergency oil drain valves located on the same side wing are designed in parallel.

[0019] As a further technical solution of the present invention: the refueling control valve is located in the lower part of the outer compartment of each fuel tank, and the refueling control valve is provided with a fuel diffuser.

[0020] As a further technical solution of the present invention: the number of one-way valves of the fuel tank partition is matched and set according to the maximum refueling flow rate, so as to ensure that the fuel level of each compartment can be quickly leveled under the maximum refueling flow rate.

[0021] As a further technical solution of the present invention: the emergency oil drain pump is installed in the inner compartment, so that only the fuel in the outer compartment and the inner compartment can be drained during emergency oil drain, while the fuel in the oil collection tank is retained due to the obstruction of the one-way valve of the oil tank partition.

[0022] As a further technical solution of the present invention: when only fuel tanks I and IV or only fuel tanks II and III can participate in emergency fuel dumping, after the fuel in the inner and outer compartments of the two fuel tanks is completely dumped, the remaining total weight of the aircraft and the fuel distribution can meet the requirements of emergency landing.

[0023] As a further technical solution of the present invention: the system also includes an emergency power supply independent of the aircraft's main power supply, used to supply power to the emergency fuel drain pump and control circuit in an emergency.

[0024] Secondly, the present invention provides a method for emergency fuel dumping of the aforementioned four-engine aircraft emergency fuel dumping system, comprising the following steps:

[0025] Initiating the oil drain procedure: Simultaneously activate the first pump control button and the second pump control button to open all emergency oil drain pumps; and simultaneously activate the first valve control button and the second valve control button to open all emergency oil drain valves;

[0026] Fuel draining procedure: Fuel is drained from the inner and outer compartments of each fuel tank through the pressure refueling line and the emergency drain line under the drive of the emergency drain pump.

[0027] Termination of fuel draining procedure: When the amount of fuel drained reaches the predetermined target amount, simultaneously operate the first valve control button and the second valve control button to close all emergency fuel draining valves, and simultaneously operate the first pump control button and the second pump control button to close all emergency fuel draining pumps.

[0028] As a further technical solution of the present invention: before the start of the oil draining step, a system self-test step is also included: checking whether the control circuit and emergency power supply status of the emergency oil draining pump and emergency oil draining valve are normal.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] 1. This invention combines a pressure refueling line and an emergency fuel drain line. Each fuel tank is equipped with an emergency fuel drain pump, and the emergency fuel drain pumps of symmetrical tanks are controlled by the same button. This allows for simultaneous fuel drain during emergency fuel release. If one emergency fuel drain pump fails, both symmetrical emergency fuel drain pumps can be shut down simultaneously to prevent fuel imbalance. The emergency fuel drain pumps of the remaining two tanks can still drain the aircraft fuel to below the required level. Emergency fuel drain valves on the left and right sides are connected in parallel and controlled by the same button. This allows for simultaneous opening or closing of both emergency fuel drain valves during emergency fuel release to prevent fuel imbalance. If one emergency fuel drain valve fails, both symmetrical emergency fuel drain valves can be shut down simultaneously. One emergency fuel drain path is also maintained on each side to prevent situations where only one side can drain fuel due to valve failure.

[0031] 2. Compared to traditional aircraft, this invention, without excessively increasing design complexity, can meet normal emergency fuel dumping requirements. Furthermore, through the arrangement of the emergency fuel dumping pump and the one-way valve on the fuel tank diaphragm, it ensures that excessive fuel is not dumped, avoiding the problem of over-dumping. The emergency fuel dumping operation logic is simple and clear, avoiding both inconsistent fuel dumping volumes on the left and right sides due to operation, thus preventing fuel imbalance, and also avoiding the inability to dump fuel in an emergency due to a single point of failure. The relevant system principles are clear and effective, and the entire system has a very high safety margin, fully ensuring the safety of the aircraft.

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of an emergency fuel dumping system for a four-engine aircraft according to the present invention.

[0034] Explanation of the markings in the diagram: 1-I oil tank; 2-II oil tank; 3-III oil tank; 4-IV oil tank; 5-Emergency drain pump; 6-Emergency drain valve I; 7-II; 8-Emergency drain valve III; 9-Emergency drain valve IV; 10-Refueling control valve; 11-One-way valve for oil tank partition; 12-Pressure refueling pipeline; 13-Emergency drain pipeline. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0036] Based on the present invention

[0037] All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0038] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0039] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited from each other.

[0040] The following is in conjunction with the appendix Figure 1 The embodiments of the present invention will be described in detail below.

[0041] Example 1

[0042] 1. System Overview

[0043] This embodiment provides an emergency fuel dumping system for a four-engine aircraft. Its core design objective is to quickly and safely release excess fuel before an emergency landing due to a malfunction after takeoff, thereby reducing the aircraft weight to within the safe landing weight. Through unique fuel tank partitioning, unidirectional fuel flow design, and symmetrical grouping control of pumps and valves, this system effectively solves the problem of fuel imbalance between the left and right sides of the fuselage that may occur in traditional fuel dumping systems, and significantly improves the system's redundancy and reliability.

[0044] 2. System Hardware Composition and Layout

[0045] For the physical architecture of this system, please refer to [link / reference]. Figure 1 Its main components and layout are as follows:

[0046] Fuel Tank Assembly: The aircraft has four main fuel tanks: Tank I, Tank II, Tank III, and Tank IV. Tanks I and II are located on the left wing, while Tanks III and IV are located on the right wing. Each tank is further divided into three compartments by ribs: an external compartment, an internal compartment, and a fuel collection tank. The fuel flow direction is designed to always be from the external compartment → internal compartment → fuel collection tank, ultimately supplying fuel to the engines from the fuel collection tank.

[0047] Fuel tank baffle check valves: Multiple fuel tank baffle check valves are installed at the bottom of the ribs between the outer and inner compartments and between the inner compartment and the fuel collection tank in each fuel tank. These check valves only allow fuel to flow in the designed direction (from the outer compartment to the inner compartment and then to the fuel collection tank) and strictly prevent reverse flow. The number of check valves is precisely calculated to ensure that the fuel level in each compartment can be quickly leveled during maximum refueling, avoiding siphoning.

[0048] Refueling control valve: A refueling control valve is installed at the bottom of the outer compartment of each fuel tank, and this valve is connected in series with the pressurized refueling line. The valve integrates a fuel diffuser to reduce the fuel flow rate during refueling, reduce the generation and accumulation of static electricity, and improve refueling safety.

[0049] Emergency Drain Pump: Each fuel tank has an emergency drain pump installed in the lower part of its inner compartment. Its inlet is located in the inner compartment, and its outlet connects to the emergency drain line. Due to the presence of a one-way valve on the fuel tank partition, when the emergency drain pump is working, it can only draw and empty the fuel in the outer and inner compartments of its own fuel tank. The fuel in the collection tank will be retained to ensure the normal operation of the engine during and after the drain process.

[0050] Piping and emergency drain valve:

[0051] Pressure refueling line: Used for normal refueling, connecting the refueling control valves of all fuel tanks.

[0052] Emergency fuel drain line: Connected to the pressurized fuel filler line, used to drain the accumulated fuel outside the engine.

[0053] Four emergency fuel drain valves (Emergency Fuel Drain Valves I to IV) are installed in parallel on the emergency fuel drain line, each controlling the drain path of its corresponding fuel tank. To improve reliability, the fuel drain valves on the left and right wings also adopt a parallel redundancy design, with the valves on the left wing (fuel tanks I and II) forming one parallel branch and the valves on the right wing (fuel tanks III and IV) forming another parallel branch. In this way, even if a single fuel drain valve fails, the other fuel drain valve on the same side can still ensure that the fuel tank on that side can be drained.

[0054] Control system:

[0055] Pump control: The emergency fuel dump pumps for fuel tanks I and IV (i.e., the outer fuel tanks on both wings) are controlled by a single primary pump control button; the emergency fuel dump pumps for fuel tanks II and III (i.e., the inner fuel tanks on both wings) are controlled by a single secondary pump control button. This design ensures that fuel consumption in the left and right wings is synchronized and symmetrical during fuel dumping, fundamentally avoiding roll torque imbalance caused by improper fuel dumping sequence.

[0056] Valve control: Similarly, emergency drain valves I and IV are controlled by the first valve control button; emergency drain valves II and III are controlled by the second valve control button.

[0057] 3. Brief Description of System Workflow

[0058] When the pilot decides to initiate emergency fuel dumping, they first simultaneously press the first and second pump control buttons and the first and second valve control buttons in the cockpit. All emergency fuel dump pumps and valves activate synchronously. Fuel is pumped from the outer and inner compartments of each fuel tank, flows through the pressurized refueling line into the emergency fuel dump line, and is finally discharged through the fuel dump port on the trailing edge of the wing or tail. The system continues to operate until the fuel level indicator reaches the predetermined safe landing fuel level. The pilot then simultaneously presses the buttons again to close all pumps and valves, ending the fuel dumping process.

[0059] Example 2

[0060] 1. Scene setting

[0061] This example describes a four-engine large passenger aircraft that, shortly after takeoff, experienced a serious engine malfunction (not a fire), prompting the crew to decide to immediately return to the airport for an emergency landing. At this point, the aircraft's total weight far exceeded its structural design's maximum landing weight, necessitating the initiation of an emergency fuel dumping procedure.

[0062] 2. Oil draining procedure

[0063] Step 1: Decision-making and preparation

[0064] The crew confirmed the malfunction and decided to dump emergency fuel and return to the airfield for a landing.

[0065] Pilots can input or query the target fuel quantity corresponding to the "safe landing weight" through the onboard computer.

[0066] The pilot confirms that the relevant circuits and emergency power supply are in normal condition via the emergency fuel dumping system control panel on the cockpit ceiling (this can be done via indicator lights or a self-test program).

[0067] Step 2: Start draining oil

[0068] Synchronous start of pumps and valves: The pilot simultaneously presses the two pump start buttons (first and second pump control buttons) and the two valve open buttons (first and second valve control buttons) on the control panel.

[0069] System Response: Instantly, all four emergency fuel dump pumps in fuel tanks I through IV began operation; simultaneously, all emergency fuel dump valves I through IV opened. Because the pumps and valves are controlled symmetrically in groups, the fuel dumping actions of the left and right wings were completely synchronized, the aircraft attitude remained stable, and there was no obvious tendency for fuel imbalance to roll.

[0070] Step 3: Monitoring and Maintenance

[0071] The pilot monitors engine parameters to ensure the remaining three engines are functioning properly (fuel supply is guaranteed by the fuel tanks).

[0072] Closely monitor the fuel quantity indicator reading for any decreases.

[0073] Maintain the aircraft in the designated fuel dumping airspace and altitude to ensure that the released fuel is fully atomized and dissipated in the atmosphere.

[0074] Step 4: Stop draining oil

[0075] When the fuel level indicator shows that the fuel level has reached or is slightly below the target level, the pilot simultaneously operates the two valve shut-off buttons (the first and second valve control buttons) to cut off the fuel drain path.

[0076] Immediately afterwards, operate both pump shut-off buttons (first and second pump control buttons) simultaneously to stop all emergency drain pumps from operating.

[0077] Step 5: Post-oil disposal

[0078] Perform the standard pre-landing checklist.

[0079] Due to the system design, even if only a portion of the fuel tanks are used for fuel dumping (in redundant mode), the remaining fuel distribution of the aircraft is balanced, and the total weight is within a safe range, allowing the aircraft to safely approach and land.

[0080] 3. Fault-tolerant mode

[0081] Assuming a minor leak occurs in the emergency fuel dumping line on the right wing during the fuel dumping process, the crew, following procedure, closes the right wing's fuel dumping valve (i.e., closes valves II and III via the second valve control button). At this point, the system enters single-sided fuel dumping mode:

[0082] Only fuel tanks I and II on the left wing continued to drain fuel.

[0083] Since the drain pumps for oil tanks I and II are controlled by different buttons, the unit can operate the remaining available pumps and valves.

[0084] According to the design, even if the fuel in the inner and outer compartments of the two fuel tanks on the left wing is completely emptied, the remaining total weight and lateral balance of the aircraft can still meet the stringent requirements for emergency landing, demonstrating the excellent safety redundancy of the system.

[0085] Example 3

[0086] This invention discloses an emergency fuel dumping system for a four-engine aircraft, comprising an emergency fuel dumping pump 5, emergency fuel dumping valves I-IV (6-9), a fuel tank bulkhead check valve 11, a refueling control valve 10, and fuel tanks. The fuel tanks include fuel tank I, fuel tank II, fuel tank III, and fuel tank IV, each divided into a collection tank, an inner compartment, and an outer compartment. Each fuel tank has an emergency fuel dumping pump 5 and a refueling control valve 10. The emergency fuel dumping pump 5 is installed in fuel tank I, located in the inner compartment, and connected to an emergency fuel dumping pipeline 1. 3 is connected to the pressure refueling pipeline 12. The refueling control valve 10 is located in the outer compartment and is connected to the pressure refueling pipeline 12. The refueling control valve 10 is used to provide on / off control for refueling tank I. The emergency drain pipeline 13 is connected to the pressure refueling pipeline 12. Emergency drain valves I to IV (6 to 9) are located on the emergency drain pipeline 13 and are designed in parallel. Several tank partition check valves 11 are provided at the bottom of the ribs between each compartment to ensure the flow sequence of fuel from the outer compartment to the inner compartment and then to the fuel collection tank, and to prevent reverse flow.

[0087] The emergency fuel dumping method for the four-engine aircraft is as follows: Open the emergency fuel dumping pumps 5 of fuel tanks I to IV, and open the emergency fuel dumping valves I to IV (6 to 9). The fuel enters the pressure refueling line 12 and the emergency fuel dumping line 13 sequentially through the emergency fuel dumping pumps 5 of each fuel tank, and is then discharged outside the aircraft through the emergency fuel dumping valves I to IV (6 to 9). After the amount of fuel discharged reaches the target amount, close the emergency fuel dumping valves I to IV (6 to 9) and shut down the emergency fuel dumping pumps 5 of fuel tanks I to IV.

[0088] Furthermore, the refueling control valve 10 is installed on the pressure refueling pipeline 12 of each oil tank and arranged in the lower part of the outer compartment, with one refueling control valve 10 for each oil tank.

[0089] Furthermore, one emergency oil drain pump 5 is provided for each oil tank and is located in the lower part of the inner compartment. The emergency oil drain pump of each oil tank is connected to the pressure refueling pipeline 12.

[0090] Furthermore, the emergency oil drain valves (6-9) are installed on the emergency oil drain pipeline, with two valves installed on each side of the wing, and the two emergency oil drain valves on each side are designed in parallel.

[0091] Furthermore, the one-way valve 11 of the fuel tank partition is located at the lower part of the rib between the outer compartment and the inner compartment, and at the lower part of the rib between the inner compartment and the fuel tank. It is used to ensure the flow sequence of fuel from the outer compartment to the inner compartment and then to the fuel tank, and to prevent it from flowing in reverse. The number of one-way valves 11 of the fuel tank partition can ensure that the fuel level in each compartment can be quickly leveled under the maximum refueling flow rate.

[0092] Example 4

[0093] This invention discloses an emergency fuel dumping system for a four-engine aircraft, comprising an emergency fuel dumping pump, an emergency fuel dumping valve, a fuel tank partition check valve, a refueling control valve, and fuel tanks. The fuel tanks include Fuel Tank I, Fuel Tank II, Fuel Tank III, and Fuel Tank IV, each divided into a collection tank, an inner compartment, and an outer compartment. Each fuel tank has an emergency fuel dumping pump and a refueling control valve. The emergency fuel dumping pump is located in Fuel Tank I, within the inner compartment, and connected to a pressure refueling pipeline via an emergency fuel dumping line. The refueling control valve is located in the outer compartment and connected to the pressure refueling line, providing on / off control for refueling Fuel Tank I. The emergency fuel dumping line is connected to the pressure refueling line, and the emergency fuel dumping valve is located on the emergency fuel dumping line in parallel. Several fuel tank partition check valves are installed at the bottom of the ribs between the compartments to ensure the sequential flow of fuel from the outer compartment to the inner compartment and then to the collection tank, and to prevent reverse flow.

[0094] Furthermore, one emergency oil drain pump is installed in each oil tank to ensure that each oil tank can drain oil in an emergency.

[0095] Furthermore, the emergency drain pumps for tanks I and IV are controlled by one control button, and the emergency drain pumps for tanks II and III are controlled by another control button, to avoid fuel imbalance caused by the pump activation sequence.

[0096] Furthermore, emergency drain valves I and IV are controlled by a single control button, and emergency drain valves II and III are controlled by a single control button, to avoid an imbalance of fuel between the left and right sides due to the valve opening sequence.

[0097] Furthermore, emergency drain valves I / II and III / IV are designed in parallel on the emergency drain pipeline to avoid the inability to drain oil in an emergency due to the failure of a single emergency drain valve;

[0098] Furthermore, the refueling control valve is equipped with a fuel diffuser to reduce the fuel flow rate entering the fuel tank and prevent static electricity buildup.

[0099] Furthermore, the number of one-way valves on the tank partition of each tank is set according to the maximum refueling flow rate, which can ensure that the fuel level in each compartment can be quickly leveled under the maximum refueling flow rate.

[0100] Furthermore, the emergency fuel drain pump is located in the inner compartment and can only drain fuel from the outer and inner compartments. Due to the presence of the one-way valve on the fuel tank partition, it cannot drain fuel from the fuel collection tank.

[0101] Furthermore, even if only fuel tanks I / IV or II / III are available for emergency fuel release, completely releasing the fuel from the inner and outer compartments of both tanks can still meet the requirements for emergency landing without causing fuel imbalance.

[0102] Furthermore, fuel tanks I and II are located on one side of the aircraft, while fuel tanks III and IV are located on the other side of the aircraft.

[0103] Furthermore, the emergency oil release method includes the following steps:

[0104] When emergency fuel draining is required, confirm the amount of fuel to be drained, open the emergency fuel drain pumps for tanks I / IV and II / III, open the emergency fuel drain valves I / IV and II / III, and close the emergency fuel drain valves I / IV and II / III after the amount of fuel drained reaches the predetermined amount. Also close the emergency fuel drain pumps for tanks I / IV and II / III.

[0105] Example 5

[0106] Fuel tanks I, II, III, and IV are all divided into a collection tank, an inner compartment, and an outer compartment. Each tank has an emergency drain pump and a refueling control valve. The emergency drain pump is located in the inner compartment of fuel tank I and is connected to the pressure refueling pipeline via an emergency drain pipeline. The refueling control valve is located in the outer compartment and is connected to the pressure refueling pipeline. The refueling control valve is used to control the refueling of fuel tank I. The emergency drain pipeline is connected to the pressure refueling pipeline, and the emergency drain valve is located on the emergency drain pipeline in parallel. Several one-way valves are installed at the bottom of the ribs between the compartments to ensure the flow sequence of fuel from the outer compartment to the inner compartment and then to the collection tank, and to prevent reverse flow.

[0107] Based on the above structure, the emergency fuel dumping method of the present invention is as follows: When the aircraft needs to dump fuel in an emergency, the target amount of fuel to be dumped is determined, and emergency fuel dumping pumps I / IV and II / III are opened, as are emergency fuel dumping valves I / IV and II / III. After the target amount of fuel is reached, emergency fuel dumping valves I / IV and II / III are closed, and emergency fuel dumping pumps I / IV and II / III are also closed. If a fault occurs in one of the emergency fuel dumping pumps during the emergency fuel dumping process, that emergency fuel dumping pump and the emergency fuel dumping pumps of the symmetrical fuel tanks are closed. At this time, the emergency fuel dumping pumps of the remaining two fuel tanks can still dump the aircraft's fuel to below the required amount. If a fault occurs in one of the emergency fuel dumping valves during the emergency fuel dumping process, that emergency fuel dumping valve and the symmetrical emergency fuel dumping valves are closed. At this time, the remaining two emergency fuel dumping valves can still ensure normal fuel dumping by the aircraft.

[0108] When the system is working normally and emergency oil draining is not required, the emergency oil drain pump 5, emergency oil drain valve I 6, emergency oil drain valve II 7, emergency oil drain valve III 8, emergency oil drain valve IV 9 and refueling control valve 10 of each oil tank are all in the closed state;

[0109] When emergency fuel dumping is required: Open emergency fuel dump pumps 5 for tanks I to IV, and open emergency fuel dump valves I to IV (6 to 9). Fuel will flow sequentially from each tank's emergency fuel dump pump 5 into the pressure refueling line 12 and the emergency fuel dump line 13, and then be dumped outside the aircraft through emergency fuel dump valves I to IV (6 to 9). Once the target fuel volume is reached, close emergency fuel dump valves I to IV (6 to 9) and shut down emergency fuel dump pumps 5 for tanks I to IV. If emergency fuel dump pump 5 for tank I malfunctions during emergency fuel dumping, shut down emergency fuel dump pumps 5 for tanks I and IV. At this time, the emergency fuel dump pumps 5 for tanks 2 and III can still drain the aircraft's fuel to below the required level. If emergency fuel dump valve I6 malfunctions during emergency fuel dumping, shut down emergency fuel dump valves I and IV (9). At this time, the remaining emergency fuel dump valves II (7) and III (8) can still ensure normal fuel dumping.

[0110] During emergency fuel dumping, as the fuel in the inner compartment is consumed, causing the fuel level in the inner compartment to fall below that in the outer compartment, fuel from the outer compartment enters the inner compartment through the one-way valve 11 of the fuel tank diaphragm under the influence of gravity. This continues until the fuel in both the inner and outer compartments is depleted, at which point the emergency fuel dumping pump 5 can no longer drain the fuel from the fuel collection tank, ensuring that the aircraft has enough remaining fuel to meet the aircraft's landing needs.

[0111] The solution is based on a clear and straightforward principle, has a simple system architecture, high operational reliability, can meet the emergency fuel dumping needs of aircraft, and has a high safety margin.

[0112] Thus, the objective of this invention has been achieved.

[0113] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An emergency fuel dumping system for a four-engine aircraft, characterized in that, include: Multiple fuel tanks, including fuel tank I (1) and fuel tank II (2) located on one side of the aircraft, and fuel tank III (3) and fuel tank IV (4) located on the other side of the aircraft; Each of the fuel tanks is divided into an outer compartment, an inner compartment and a collection tank, and a fuel tank partition check valve (11) is provided at the bottom of the rib between each compartment to ensure that fuel flows from the outer compartment to the inner compartment and then to the collection tank, and to prevent it from flowing in the opposite direction. Emergency oil drain pump (5), one of which is provided at the bottom of the inner compartment of each oil tank, is used to pump fuel in the inner and outer compartments of the oil tank; The pressure refueling pipeline (12) is connected to the refueling control valve (10) of each oil tank; An emergency fuel drain line (13) is connected at one end to the pressure fuel filling line (12) and at the other end to drain fuel out of the machine. Multiple emergency drain valves (6, 7, 8, 9) are connected in parallel on the emergency drain pipeline (13); Among them, the emergency oil drain pumps (5) of oil tank I (1) and oil tank IV (4) are controlled by the first pump control button, and the emergency oil drain pumps (5) of oil tank II (2) and oil tank III (3) are controlled by the second pump control button. The emergency drain valves (6, 9) corresponding to oil tank I (1) and oil tank IV (4) are controlled by the first valve control button, and the emergency drain valves (7, 8) corresponding to oil tank II (2) and oil tank III (3) are controlled by the second valve control button.

2. The emergency fuel dumping system for a four-engine aircraft according to claim 1, characterized in that, The emergency drain valves (6, 7, 8, 9) are arranged in two parallel groups on the emergency drain pipeline (13). The first parallel branch includes emergency drain valves (6, 7) that control the fuel flow of tank I (1) and tank II (2), and the second parallel branch includes emergency drain valves (8, 9) that control the fuel flow of tank III (3) and tank IV (4).

3. The emergency fuel dumping system for a four-engine aircraft according to claim 1, characterized in that, The two emergency oil drain valves located on the same side of the wing are designed in parallel.

4. The emergency fuel dumping system for a four-engine aircraft according to claim 1, characterized in that, The refueling control valve (10) is located in the lower part of the outer compartment of each fuel tank, and a fuel diffuser is provided on the refueling control valve (10).

5. The emergency fuel dumping system for a four-engine aircraft according to claim 1, characterized in that, The number of one-way valves (11) on the tank diaphragm is matched and set according to the maximum refueling flow rate to ensure that the fuel level in each compartment can be quickly leveled under the maximum refueling flow rate.

6. The emergency fuel dumping system for a four-engine aircraft according to claim 1, characterized in that, The emergency oil drain pump (5) is located in the inner compartment, so that only the fuel in the outer and inner compartments can be drained during emergency oil drain, while the fuel in the oil collection tank is retained due to the obstruction of the one-way valve (11) of the oil tank partition.

7. The emergency fuel dumping system for a four-engine aircraft according to claim 6, characterized in that, When only fuel tanks I (1) and IV (4) or only fuel tanks II (2) and III (3) are available to participate in emergency fuel dumping, after the fuel in the inner and outer compartments of these two fuel tanks is completely dumped, the remaining total weight of the aircraft and the distribution of fuel can meet the requirements for emergency landing.

8. The emergency fuel dumping system for a four-engine aircraft according to claim 1, characterized in that, The system also includes an emergency power supply independent of the aircraft's main power supply, used to power the emergency fuel drain pump (5) and control circuitry in emergency situations.

9. A method for emergency fuel dumping using the four-engine aircraft emergency fuel dumping system as described in claim 1, characterized in that, Includes the following steps: Start the oil draining procedure: Simultaneously start the first pump control button and the second pump control button to open all emergency oil draining pumps (5); and simultaneously start the first valve control button and the second valve control button to open all emergency oil draining valves (6, 7, 8, 9); Fuel draining procedure: Fuel is drained from the inner and outer compartments of each fuel tank through the pressure refueling line (12) and the emergency fuel draining line (13) under the drive of the emergency fuel draining pump (5); Termination of fuel discharge procedure: When the amount of fuel discharged reaches the predetermined target amount, simultaneously operate the first valve control button and the second valve control button to close all emergency fuel discharge valves (6, 7, 8, 9), and simultaneously operate the first pump control button and the second pump control button to close all emergency fuel discharge pumps (5).

10. The method according to claim 9, characterized in that, Before the start of the oil draining step, a system self-test step is also included: checking whether the control circuit and emergency power supply status of the emergency oil draining pump (5) and emergency oil draining valve (6, 7, 8, 9) are normal.

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