Self-preheating starting system of turboshaft engine under extremely cold condition and use control method

Abstract

The application discloses a self-preheating starting system of a turboshaft engine under extremely cold conditions and a use control method, which comprises a fuel tank, an oil tank, an oil inlet circuit connected to the oil tank, an electricity accumulator, an engine core, a starting auxiliary combustion device and a control system. The starting auxiliary combustion device is used for introducing part of fuel from the fuel tank, introducing part of air under the drive of the electricity accumulator to form high-pressure gas, and making the high-pressure gas and the fuel burn to generate high-temperature gas. The oil inlet circuit is connected to the output side of the starting auxiliary combustion device, so that the high-temperature gas preheats the oil in the oil inlet circuit, and the output end of the oil inlet circuit is also connected to multiple bearing cavities of the engine core, so that the preheated oil enters the multiple bearing cavities of the engine core to lubricate. The system utilizes the fuel of the engine as energy, accurately and quickly preheats the oil of the engine and the core through an internal high-efficiency combustion heating system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of turboshaft engines, in particular, to a turboshaft engine self-preheating starting system under extremely cold conditions. Furthermore, the present application also relates to a turboshaft engine self-preheating starting system control method using the above-mentioned turboshaft engine self-preheating starting system under extremely cold conditions. BACKGROUND

[0002] The turboshaft engine under extremely cold conditions (such as -40℃ or even lower) is prone to cause abnormal starting or starting failure due to reasons such as thick oil, reduced rotor-stator gap, and poor performance of the battery under extremely cold conditions. Specifically:

[0003] 1. Oil solidification problem: the viscosity of engine oil increases sharply at low temperature, and even solidifies, resulting in a large resistance torque of friction pairs such as main shaft bearings, and the starting motor torque is insufficient to drive the engine to the ignition speed;

[0004] 2. Rotor-stator gap problem: metal parts may cause dynamic gap (such as blade tip gap) to change, thereby affecting aerodynamic performance, and even causing collision and abrasion; at the same time, the cold brittleness of the material increases, and there is a risk of damage under a large starting load;

[0005] 3. Battery performance drop: low temperature causes the capacity and voltage output of the battery to drop significantly, which cannot provide sustained and stable strong power for the starter and control system, resulting in interruption of the starting process;

[0006] 4. Poor fuel atomization: although the freezing point of aviation coal is low, the viscosity is too large at low temperature, which may cause poor atomization quality, affecting ignition and initial combustion stability.

[0007] In the field of aviation, especially turboshaft engines for helicopters and drones, the deployment environment is becoming more and more severe, and polar exploration, high-latitude rescue, and winter military operations all require the engine to have reliable starting ability at extremely low temperatures. At present, the most common treatment is the combination of "external ground power supply vehicle (GPU) + external hot air warming vehicle".

[0008] 1. External ground power supply vehicle (GPU): provides a large and high-power external power source to replace or assist the on-board battery to provide enough power for the starter to overcome the problem of large load of the starter and poor performance of the battery at low temperature;

[0009] 2. External hot air warming vehicle: This is a large independent device, which is equipped with a burner and a high-power fan inside. When working, it inhales air from the environment, heats it (usually by burning fuel) to produce high-temperature and high-flow hot air. The hot air is connected to the engine bleed air pipe or a special heat preservation sleeve of the aircraft through a special flexible pipeline, and the engine core (such as the compressor and the combustion chamber section) is externally heated. At the same time, the engine oil system is also assisted to be heated.

[0010] The existing treatment scheme is to provide additional energy (electricity and heat) by external equipment to forcibly raise the temperature of the engine and the lubricating system to make it enter the startable temperature range, and its respective shortcomings are as follows:

[0011] 1. Dependence on large external equipment: Special power supply vehicles and hot air warming vehicles must be equipped, which are large in size, expensive in price, and need to be transported to the work site by special transport tools (such as trucks), which are difficult to guarantee in remote polar or front-line airports;

[0012] 2. Complex guarantee process and long time-consuming: Ground personnel need to complete a series of complex processes such as equipment docking and preheating operation, and the entire preheating process may take tens of minutes to hours, which cannot realize rapid emergency start, and seriously reduces the flexibility and response speed of the task;

[0013] 3. Poor portability: This scheme cannot be applied to field sites lacking ground support or unmanned helicopters;

[0014] 4. Low energy efficiency: In the process of heating the ambient air by the hot air warming vehicle, most of the heat is lost in the atmosphere, and the proportion of heat used for heating the engine is low, resulting in serious energy waste;

[0015] 5. Safety risk: The high-temperature hot air pipeline has the risk of scalding personnel or damaging on-board equipment; the hot air warming vehicle itself is also a fire source, which needs to be extremely careful in flammable and explosive environments. SUMMARY

[0016] The present application provides a turbo-shaft engine self-preheating starting system under extremely cold conditions and a use control method to solve the technical problems of the existing dependence on external equipment to provide additional energy, which is difficult to guarantee in remote polar or front-line airports, cannot realize rapid emergency start, seriously reduces the flexibility and response speed of the task, cannot be applied to field sites lacking ground support or unmanned helicopters, serious energy waste, high-temperature hot air pipeline has the risk of scalding personnel or damaging on-board equipment, and the hot air warming vehicle itself is also a fire source, which needs to be extremely careful in flammable and explosive environments.

[0017] The technical scheme adopted by the present application is as follows:

[0018] The application discloses a self-preheating starting system of a turbo-shaft engine under extremely cold conditions, which comprises a fuel tank for supplying fuel, an oil tank for supplying lubricating oil, a lubricating oil inlet circuit connected to the oil tank, an electric energy storage device, an engine core, a starting auxiliary combustion device and a control system connected to the engine core and the starting auxiliary combustion device.

[0019] Further, the starting auxiliary combustion device comprises an auxiliary motor connected to the electric energy storage device, an auxiliary motor-driven air compressor connected to the auxiliary motor, an auxiliary combustion chamber connected to the fuel tank, and the auxiliary motor and the auxiliary motor-driven air compressor are connected to the control system; the auxiliary motor is used to start and drive the auxiliary motor-driven air compressor to rotate under the action of the electric energy storage device, and the auxiliary motor-driven air compressor is used to introduce air to form high-pressure air after rotating, and then part of the high-pressure air is input into the auxiliary combustion chamber; the auxiliary combustion chamber is used to automatically ignite the mixed fuel and high-pressure air to generate high-temperature fuel gas; and the lubricating oil inlet circuit extends to an exhaust port of the auxiliary combustion chamber.

[0020] Further, the engine core mainly comprises a compressor, a combustion chamber and a turbine, and the multiple bearing cavities comprise an accessory drive bearing cavity, a compressor bearing cavity and a turbine bearing cavity; the starting auxiliary combustion device further comprises a high-temperature fuel gas channel connected to an exhaust end of the auxiliary combustion chamber; the lubricating oil inlet circuit comprises a lubricating oil inlet main pipe, an auxiliary lubricating oil pump arranged in the lubricating oil inlet main pipe, two lubricating oil inlet branch pipes connected to an output end of the lubricating oil inlet main pipe, an oil inlet end of the lubricating oil inlet main pipe is connected to the oil tank, an oil outlet end of the lubricating oil inlet main pipe extends out through the high-temperature fuel gas channel, and oil outlet ends of the two lubricating oil inlet branch pipes are respectively connected to the compressor bearing cavity and the turbine bearing cavity; the self-preheating starting system further comprises a lubricating oil return circuit, the lubricating oil return circuit comprises two lubricating oil return branch pipes, a lubricating oil return main pipe connected to oil outlet ends of the two lubricating oil return branch pipes, and a lubricating oil return pump arranged in the lubricating oil return main pipe, oil inlet ends of the two lubricating oil return branch pipes are respectively connected to the compressor bearing cavity and the turbine bearing cavity, and an oil outlet end of the lubricating oil return main pipe is communicated with the oil tank.

[0021] Further, the self-preheating starting system further comprises a sealing gas path, an air inlet end of the sealing gas path being communicated with an air outlet end of the auxiliary electric compressor, and an air outlet end of the sealing gas path being connected to multiple bearing cavities of the engine core to introduce high-pressure gas for sealing and preventing oil leakage; the self-preheating starting system further comprises a bleed air path and a switch valve arranged in the bleed air path, the switch valve being connected to the control system, an air inlet end of the bleed air path being communicated with the high-temperature gas passage, and an air outlet end of the bleed air path being connected to an air inlet of the compressor.

[0022] Further, the self-preheating starting system further comprises a fuel auxiliary flow path, a fuel main flow path and a fuel return flow path; the fuel auxiliary flow path comprises an auxiliary fuel pipe connected to the fuel tank and the auxiliary combustion chamber, and an auxiliary fuel pump arranged in the auxiliary fuel pipe, the auxiliary fuel pump being connected to the control system; the fuel main flow path comprises a main fuel pipe connected to the fuel tank and the combustion chamber, and a main fuel pump arranged in the main fuel pipe, the main fuel pump being connected to the control system, and the main fuel pipe extending to pass through the high-temperature gas passage; an air inlet end of the fuel return flow path is connected to an air outlet end of the high-temperature gas passage, and an air outlet end of the fuel return flow path is connected to the storage device tank for mounting the storage device.

[0023] According to another aspect of the present application, a control method of a self-preheating starting system of a turboshaft engine under extremely cold conditions is also provided, which uses the self-preheating starting system of the turboshaft engine under extremely cold conditions according to any one of the above embodiments, and the control method comprises the following steps: system starting trigger: an operator initiatively triggers or the control system automatically triggers according to the ambient temperature and / or the engine state; combustion heating: the auxiliary combustion device introduces part of the fuel and part of the air to form high-pressure gas, and makes the high-pressure gas and the introduced fuel burn to generate high-temperature gas; heat transfer and distribution: the high-temperature gas is used to preheat the lubricating oil, the fuel and the engine core, and to keep the storage device warm; closed-loop control: multiple temperature sensors and multiple pressure sensors are added in the self-preheating starting system, so that the control system calculates and dynamically adjusts the fuel supply amount of the auxiliary combustion chamber and the high-pressure gas flow according to a preset optimal preheating temperature curve, and then accurately controls the combustion power in the auxiliary combustion chamber and the temperature of the high-temperature gas discharged, to prevent overheating and damage to the equipment.

[0024] Further, the step of combustion heating specifically comprises the following steps: the control system controls the auxiliary fuel pump to extract a small amount of fuel from the fuel tank and deliver the fuel to the auxiliary combustion chamber; the storage device controls the auxiliary electric compressor to work to generate high-pressure gas, and the high-pressure gas is supplied to the auxiliary combustion chamber for combustion in one way and to multiple bearing cavities in the engine core for sealing in another way; the fuel and the high-pressure gas are mixed in the auxiliary combustion chamber and ignited by an igniter to generate stable and controllable high-temperature gas.

[0025] Further, the step of "closed-loop control" specifically comprises the following steps: adding multiple temperature sensors and multiple pressure sensors in the self-preheating starting system to monitor multiple temperatures and pressures in real time and feed back to the control system; the control system calculates and dynamically adjusts the fuel supply amount of the auxiliary combustion chamber and the high-pressure gas flow according to the preset optimal preheating temperature curve, and then accurately controls the combustion power in the auxiliary combustion chamber and the temperature of the high-temperature gas discharged, so as to prevent overheating and damage the equipment. After preheating, the engine is started normally: when the control system monitors that the oil temperature and the engine core metal temperature have reached the preset safe starting value, the control system automatically closes the starting auxiliary combustion device; then the control system controls the engine to start according to the standard normal starting program.

[0026] Further, the step of "the control system calculates and dynamically adjusts the fuel supply amount of the auxiliary combustion chamber and the high-pressure gas flow according to the preset optimal preheating temperature curve, and then accurately controls the combustion power in the auxiliary combustion chamber and the temperature of the high-temperature gas discharged, so as to prevent overheating and damage the equipment" specifically comprises the following: let the air flow of the auxiliary electric compressor be W1, the speed of the auxiliary motor be N, the inlet pressure of the auxiliary electric compressor be P0, the inlet temperature of the auxiliary electric compressor be T0, the characteristic constant of the auxiliary electric compressor be K (geometric size, efficiency related), let the air flow of the sealed gas path be W2, let the inlet flow of the auxiliary combustion chamber be W3, then W3=W1-W2; let the fuel flow of the auxiliary combustion chamber be W4, the outlet gas flow temperature of the auxiliary electric compressor be T1, the oil temperature in the oil tank be T2, the high-temperature gas temperature be T4, the fuel combustion efficiency be ξ, the fuel heat value be LHV, and the air constant-pressure specific heat capacity be C; then: W1=K×N×P0 / T0 0.5 ; then T4=(W4×ξ×LHV) / (W3×C); according to the measured N and T2, the fuel flow W4 is controlled to obtain the required T4.

[0027] Further, the control method for the self-preheating starting system further comprises the step of safety protection: adding a flame detector, an over-temperature sensor and an over-pressure sensor in the self-preheating starting system, so that when an abnormality occurs, the control system immediately cuts off the fuel supply of the auxiliary combustion chamber, and at the same time sends an alarm prompt to the operator.

[0028] The present application has the following beneficial effects:

[0029] The self-preheating starting system of the present application is a highly integrated, self-sufficient starting system under extremely cold conditions, and its core idea is to use the fuel of the engine itself as energy, and accurately and quickly preheat the engine oil and core engine through an internal high-efficiency combustion heating system (auxiliary starting combustion device), specifically as follows:

[0030] 1. Integrated design: The combustion heating system and control system are highly integrated in the engine accessory case or nearby, without relying on any external equipment, so the overall volume of the system is small, the portability is good, and no ground support is needed, which can be applied to any aircraft deploying the engine, including unmanned helicopters, etc., and is also suitable for remote polar or frontier airports;

[0031] 2. Using its own fuel as energy source: Energy self-sufficiency is achieved, and the energy utilization rate is high;

[0032] 3. Intelligent closed-loop control: Unified control by the engine control system, completely autonomous starting ability in extreme cold conditions without ground support; fully automatic, safe and efficient preheating process, which can greatly shorten the preparation time and improve the task response ability and response flexibility; also simplifies the operation process, reduces human error, and improves safety.

[0033] In addition to the purposes, features and advantages described above, the present application has other purposes, features and advantages. The present application will be further described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0034] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application, illustrate preferred embodiments of the application and assist in explaining the application. The drawings included are:

[0035] Figure 1 is a schematic diagram of the self-preheating starting system of the turboshaft engine in extreme cold conditions according to the preferred embodiment of the present application.

[0036] Legend:

[0037] 1, fuel tank; 2, oil tank;

[0038] 31, main oil inlet pipe; 32, auxiliary oil pump;

[0039] 4, power storage device;

[0040] 5, engine core; 51, compressor; 52, combustion chamber; 53, turbine;

[0041] 6, starting auxiliary combustion device; 61, auxiliary motor; 62, auxiliary motor-driven compressor; 63, auxiliary combustion chamber; 64, high-temperature gas passage;

[0042] 71, main oil return pipe; 72, oil return pump;

[0043] 8, sealing gas path; 9, bleed air path;

[0044] 101, auxiliary fuel pipe; 102, auxiliary fuel pump;

[0045] 111 main fuel pipe; 112 main fuel pump;

[0046] 12, fuel gas return path. DETAILED DESCRIPTION

[0047] The embodiments of the present application will be described in detail with reference to the drawings, of which various modifications can be implemented by the following described embodiments, which are limited and covered. The examples of the embodiments are shown in the drawings, in which the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are used to explain the present application, but cannot be interpreted as a limitation of the present application.

[0048] Those skilled in the art can understand that, unless specifically stated, the wording "comprising" used in the specification of the present application means that the features, integers, steps, operations, parts and / or components are present, but does not exclude the presence or addition of one or more other features, integers, steps, operations, parts, components and / or combinations thereof. It should be understood that when we say that a part is "connected" to another part, it can be directly connected to the other part or connected through an intermediate part. The wording "and / or" used herein includes all or any unit and all combinations of the associated listed items. The terms "first" and "second" and the like in the specification and claims of the present application are used to distinguish different objects, not to describe a specific order.

[0049] Reference Figure 1 , the preferred embodiment of the present application provides a self-preheating starting system for turboshaft engine in extremely cold conditions, comprising: a fuel tank 1 for supplying fuel, a lubricating oil tank 2 for supplying lubricating oil, a lubricating oil inlet circuit connected to the lubricating oil tank 2, an electric energy storage device 4, an engine core 5, a starting auxiliary combustion device 6, and a control system connected to the engine core 5 and the starting auxiliary combustion device 6. The input side of the starting auxiliary combustion device 6 is connected to the fuel tank 1 and the electric energy storage device 4 respectively, for introducing part of the fuel from the fuel tank 1, while introducing part of the air under pressure to form high pressure gas under the drive of the electric energy storage device 4, and making the high pressure gas and the introduced part of the fuel burn to produce high temperature gas. The lubricating oil inlet circuit is connected to the output side of the starting auxiliary combustion device 6, so that the generated high temperature gas preheats the lubricating oil in the lubricating oil inlet circuit, and the output end of the lubricating oil inlet circuit is also connected to multiple bearing cavities of the engine core 5, so that the preheated lubricating oil enters the multiple bearing cavities of the engine core 5 for lubrication.

[0050] The self-preheating starting system of the turbo-shaft engine of the application is operated as follows: the operator manually triggers or the control system automatically triggers starting according to preset conditions, the fuel in the fuel tank 1 enters the starting auxiliary combustion device 6, at the same time, the outside air also enters the starting auxiliary combustion device 6, and is compressed to form high-pressure gas under the action of the starting auxiliary combustion device 6, then the high-pressure gas is mixed with the fuel and burned to form high-temperature gas and is outputted; at this time, the low-temperature lubricating oil in the lubricating oil tank 2 is forced to enter the lubricating oil inlet circuit, when the low-temperature lubricating oil in the lubricating oil inlet circuit passes through the output side of the starting auxiliary combustion device 6, the temperature of the lubricating oil is rapidly increased after heat exchange with the high-temperature gas, then the heated lubricating oil enters the bearing cavity of the engine core 5 under the action of the lubricating oil inlet circuit, and the bearing, gear and other components are preheated, and then the lubricating oil returns to the lubricating oil tank 2 to form a cycle; when the engine control system monitors that the lubricating oil temperature and the core metal temperature have reached the preset safe starting value, the control system automatically closes the starting auxiliary combustion device 6, then the control system controls the engine to start according to the standard normal starting procedure, at this time, since the lubricating oil resistance is greatly reduced, the power of the power storage device 4 is sufficient to drive the starter, and the engine can smoothly reach the ignition speed and successfully ignite.

[0051] The self-preheating starting system of the application is a highly integrated, self-sufficient starting system under extremely cold conditions, and the core idea is as follows: using the fuel of the engine as energy, the engine lubricating oil and the core are accurately and quickly preheated through a built-in high-efficiency combustion heating system (the starting auxiliary combustion device 6), and the specific process is as follows:

[0052] 1. Integrated design: the combustion heating system and the control system are highly integrated in the engine accessory case or nearby, and do not depend on any external equipment, so the system has small overall volume, good portability, and does not require ground support, and can be applied to any aircraft deploying the engine, including unmanned helicopters and the like, and is also suitable for remote polar or frontier airports;

[0053] 2. Using self fuel as energy: realizing self-sufficiency of energy, and high energy utilization rate;

[0054] 3. Intelligent closed-loop control: controlled by the engine control system, realizing completely autonomous starting ability under extremely cold conditions without ground support; realizing automatic, safe and efficient preheating process, which can greatly shorten the preparation time, improve the task response ability and response flexibility; also simplifying the operation process, reducing human errors and improving safety.

[0055] Optionally, as Figure 1As shown, the starting auxiliary combustion device 6 includes an auxiliary motor 61 connected to the power accumulator 4, an auxiliary electric compressor 62 connected to the auxiliary motor 61, an auxiliary combustion chamber 63 connected to the fuel tank 1, and the auxiliary motor 61 and the auxiliary electric compressor 62 are respectively connected to the control system. The auxiliary motor 61 is used to start under the action of the power accumulator 4 to drive the auxiliary electric compressor 62 to rotate, and the auxiliary electric compressor 62 rotates to introduce air to increase the pressure to form high-pressure gas and then part of the high-pressure gas is input into the auxiliary combustion chamber 63. The auxiliary combustion chamber 63 is used for automatic ignition to make the introduced fuel and high-pressure gas mixed and burned to generate high-temperature gas. The oil inlet circuit extends to the exhaust port of the auxiliary combustion chamber 63. In operation, the power accumulator 4 supplies power to make the auxiliary motor 61 operate, the auxiliary motor 61 drives the auxiliary electric compressor 62 to start, external air enters the auxiliary electric compressor 62 and is compressed to form high-pressure gas after being acted on by the auxiliary electric compressor 62, and the high-pressure gas is partially introduced into the auxiliary combustion chamber 63; At this time, the fuel in the fuel tank 1 also partially enters the auxiliary combustion chamber 63; The high-pressure gas and the fuel are ignited and fully burned in the auxiliary combustion chamber 63 to form high-temperature gas, and the high-temperature gas is discharged outwardly from the exhaust port of the auxiliary combustion chamber 63.

[0056] Optionally, as shown, Figure 1 The engine core 5 mainly includes a compressor 51, a combustion chamber 52 and a turbine 53, and the multiple bearing cavities include an accessory drive bearing cavity, a compressor bearing cavity and a turbine bearing cavity. The starting auxiliary combustion device 6 further includes a high-temperature gas passage 64 connected to the exhaust end of the auxiliary combustion chamber 63. The oil inlet circuit includes an oil inlet main pipe 31, an auxiliary oil pump 32 arranged in the oil inlet main pipe 31, two oil inlet branch pipes connected to the output end of the oil inlet main pipe 31, the oil inlet end of the oil inlet main pipe 31 is connected to the oil tank 2, the oil outlet end of the oil inlet main pipe 31 extends out after passing through the high-temperature gas passage 64, and the oil outlet ends of the two oil inlet branch pipes are respectively connected to the compressor bearing cavity and the turbine bearing cavity. The self-preheating starting system further includes an oil return circuit, the oil return circuit includes two oil return branch pipes, an oil return main pipe 71 connected to the oil outlet ends of the two oil return branch pipes, and an oil return pump 72 arranged in the oil return main pipe 71, the oil inlet ends of the two oil return branch pipes are respectively connected to the compressor bearing cavity and the turbine bearing cavity, and the oil outlet end of the oil return main pipe 71 is communicated with the oil tank 2. In operation, the low-temperature oil in the oil tank 2 enters the oil inlet main pipe 31 under the action of the auxiliary oil pump 32, and then enters the high-temperature gas passage 64 with the oil inlet main pipe 31, exchanges heat with the high-temperature gas in the high-temperature gas passage 64, and then enters the two oil inlet branch pipes, and then enters the compressor bearing cavity and the turbine bearing cavity through the two oil inlet branch pipes, so as to preheat the bearings and gears in the bearing cavities. Then, the oil preheating the bearings and gears under the action of the oil return pump 72 enters the oil return main pipe 71 through the two oil return branch pipes, and finally flows back to the oil tank 2 through the oil return main pipe 71 to form an oil circulation.

[0057] Optionally, as shown,Figure 1 As shown, the self-preheating starting system further comprises a sealing gas path 8, an air inlet end of the sealing gas path 8 being communicated with an air outlet end of the auxiliary electric compressor 62, and an air outlet end of the sealing gas path 8 being connected to multiple bearing cavities of the engine core 5 for introducing high-pressure air to seal and prevent oil leakage; specifically, the sealing gas path 8 enters the accessory drive bearing cavity, the compressor bearing cavity and the turbine bearing cavity respectively through multiple gas path branches. The oil leakage prevention principle of the engine core: the core principle is to establish an air area with slightly higher pressure on the path where the oil may leak, and use the pressure difference to "push back" or block the oil in the area where it should be; during normal operation of the engine, high-pressure air is generally introduced from the compression components of the engine for sealing / oil leakage prevention, but at the initial starting or preheating stage of the engine, the compression components have not formed high-pressure air, and it is difficult to effectively seal, at which time the high-pressure air formed by the auxiliary electric compressor 62 in the application can be used for sealing. In operation, after starting the auxiliary electric compressor 62, external air enters it, and high-pressure air is formed after being compressed by the auxiliary electric compressor 62; at this time, one way of high-pressure air enters the auxiliary combustion chamber 63, mixes with fuel and burns to form high-temperature gas; the other way of high-pressure air passes through the sealing gas path 8 as needed, passes through the gas path main pipe and multiple gas path branches, and flows to multiple bearing cavities and other positions in the engine core 5 that need to be sealed.

[0058] Optionally, as shown in FIG. 1, Figure 1 As shown, the self-preheating starting system further comprises an air bleeding path 9 and a switch valve arranged in the air bleeding path 9, the switch valve being connected to a control system, an air inlet end of the air bleeding path 9 being communicated with the high-temperature gas passage 64, and an air outlet end of the air bleeding path 9 being connected to an air inlet of the compressor 51. In operation, the high-temperature gas in the high-temperature gas passage 64 is also partially introduced into the air inlet of the compressor 51 of the engine core 5 through a controllable valve pipe, i.e., the air bleeding path 9, to gently warm the engine core 5.

[0059] Optionally, as shown in FIG. 1, Figure 1As shown, the self-preheating starting system further comprises a fuel auxiliary flow path, a fuel main flow path and a fuel gas return flow path 12. The fuel auxiliary flow path comprises an auxiliary fuel pipe 101 connecting the fuel tank 1 and the auxiliary combustion chamber 63, and an auxiliary fuel pump 102 arranged in the auxiliary fuel pipe 101, the auxiliary fuel pump 102 being connected to the control system; in operation, part of the fuel in the fuel tank 1 is supplied into the auxiliary combustion chamber 63 through the auxiliary fuel pipe 101 by the auxiliary fuel pump 102. The fuel main flow path comprises a main fuel pipe 111 connecting the fuel tank 1 and the combustion chamber 52, and a main fuel pump 112 arranged in the main fuel pipe 111, the main fuel pump 112 being connected to the control system, the main fuel pipe 111 extending to pass through the high-temperature fuel gas passage 64; in operation, the fuel in the fuel tank 1 enters the main fuel pipe 111 under the action of the main fuel pump 112, and passes through the main fuel pipe 111 to pass through the high-temperature fuel gas passage 64, the fuel exchanges heat with the high-temperature fuel gas, and then is supplied into the combustion chamber 52 through the main fuel pipe 111, so that the fuel is preheated by the high-temperature fuel gas, the fuel atomization effect is improved, and the stability of ignition and initial combustion is ensured. The intake end of the fuel gas return flow path 12 is connected to the exhaust end of the high-temperature fuel gas passage 64, and the exhaust end of the fuel gas return flow path 12 is connected to the storage battery tank for mounting the storage battery 4; in operation, the warm air in the high-temperature fuel gas passage 64 is guided into the storage battery tank through the fuel gas return flow path 12, so as to prevent the performance of the storage battery 4 from being attenuated due to low temperature, and to enable the storage battery 4, generally a storage battery, to provide continuous and stable strong power for the starter and the control system, and to ensure smooth starting process.

[0060] Referring to Figure 1 The preferred embodiment of the present application further provides a control method for the self-preheating starting system of the turboshaft engine under extremely cold conditions, which uses the self-preheating starting system of the turboshaft engine under extremely cold conditions according to any one of the above embodiments, and comprises the following steps:

[0061] S10: system starting trigger: operator initiatively starting trigger, or control system automatically starting trigger according to environmental temperature and / or engine state;

[0062] S20: combustion heating: the starting auxiliary combustion device 6 introduces part of the fuel, introduces part of the air to pressurize to form high-pressure gas, and makes the high-pressure gas and the introduced fuel burn to generate high-temperature fuel gas;

[0063] S30: heat transfer and distribution: using the high-temperature fuel gas to preheat the lubricating oil, the fuel and the engine core 5, and to keep the storage battery 4 warm;

[0064] S40: Closed-loop control: Multiple temperature sensors and multiple pressure sensors are added in the self-preheating starting system, so that the control system calculates and dynamically adjusts the fuel supply and high-pressure gas flow of the auxiliary combustion chamber 63 according to the preset optimal preheating temperature curve, and then accurately controls the combustion power and the temperature of the high-temperature gas discharged from the auxiliary combustion chamber 63, so as to prevent overheating and damage to the equipment.

[0065] The self-preheating starting system of the application uses a control method that is uniformly controlled by the engine control system, realizes completely autonomous starting ability in extremely cold conditions, does not require ground support, and can be applied to any aircraft that deploys the engine, including unmanned helicopters; also realizes a fully automatic, safe and efficient preheating process, which can greatly shorten the preparation time and improve the task response ability and response flexibility; at the same time, it also simplifies the operation process, reduces human error and improves safety.

[0066] Optionally, the step "S10: System startup trigger" is specifically operated as follows: the pilot or the flight control computer issues a low-temperature starting instruction; the engine control system detects the ambient temperature and the engine state, and if it is lower than the set threshold (such as -20℃), the self-preheating starting system of the application is automatically activated.

[0067] Optionally, the step "S20: Combustion heating" specifically includes the following steps:

[0068] S201: The control system controls the auxiliary fuel pump 102 to extract a small amount of fuel from the fuel tank 1 and deliver it to the auxiliary combustion chamber 63;

[0069] S202: The power storage device 4 controls the auxiliary electric compressor 62 to work to generate high-pressure gas, and the high-pressure gas is supplied to the auxiliary combustion chamber 63 for combustion and to multiple bearing cavities in the engine core 5 for sealing;

[0070] S203: The fuel and high-pressure gas are mixed in the auxiliary combustion chamber 63 and ignited by the igniter to produce stable and controllable high-temperature gas.

[0071] Specifically, a small auxiliary electric compressor 62 (powered by an on-board battery) starts to work, external air enters the auxiliary electric compressor 62, and high-pressure gas is formed after being compressed by the auxiliary electric compressor 62; at this time, one way of high-pressure gas enters the auxiliary combustion chamber 63, mixes with fuel and burns to form high-temperature gas; the other way of high-pressure gas passes through the sealing gas path 8 as needed, flows through the air bleeding pipe to the positions that need to be sealed, such as the bearing cavities of the engine.

[0072] Optionally, the step "S30: Heat transfer and distribution" specifically includes the following:

[0073] Engine oil preheating circuit: the low-temperature engine oil of the engine is forced to flow through the exhaust side of the auxiliary combustion chamber 63 by an auxiliary oil pump 32, and absorbs the heat of the high-temperature combustion gas, so that the temperature of the engine oil is rapidly increased; the engine oil after being heated flows back to the engine oil system, and preheats the bearings, gears and other components;

[0074] Fuel preheating circuit: the fuel in the fuel pipeline between the helicopter fuel tank 1 and the engine is heated, and the fuel atomization quality is improved;

[0075] Core engine preheating circuit: the high-temperature combustion gas is slightly introduced into the compressor inlet of the engine through a controllable valve air guide path 9, and the core engine 5 of the engine is gently warmed up;

[0076] Battery heat preservation: a warm air is introduced into the battery cabin to prevent the performance of the battery from being degraded due to low temperature.

[0077] Therefore, the system can simultaneously preheat the engine oil, fuel, core engine 5 and battery, and the energy utilization rate is high.

[0078] Optionally, the step "S40: closed-loop control" specifically includes the following steps:

[0079] S401: a plurality of temperature sensors and a plurality of pressure sensors are added in the self-preheating starting system, so as to monitor the temperature and pressure at multiple places in real time and feed back to the control system; specifically, a plurality of temperature sensors and pressure sensors are built in the system, so as to monitor the outlet temperature and pressure of the engine oil, the core engine preheating point temperature, the combustion chamber temperature and the like in real time;

[0080] S402: the control system calculates and dynamically adjusts the fuel supply amount and high-pressure gas flow of the auxiliary combustion chamber 63 according to the preset optimal preheating temperature curve, and then accurately controls the combustion power in the auxiliary combustion chamber 63 and the temperature of the high-temperature combustion gas discharged, so as to prevent overheating and damage the equipment;

[0081] S403: the preheating is completed, and the engine is normally started:

[0082] When the control system monitors that the engine oil temperature and the metal temperature of the core engine 5 have reached the preset safe starting value, the control system automatically closes the starting auxiliary combustion device 6.

[0083] Then, the control system controls the engine to start according to the standard normal starting program.

[0084] In this optional scheme, the step "S402: the control system calculates and dynamically adjusts the fuel supply amount and high-pressure gas flow of the auxiliary combustion chamber 63 according to the preset optimal preheating temperature curve, and then accurately controls the combustion power in the auxiliary combustion chamber 63 and the temperature of the high-temperature combustion gas discharged, so as to prevent overheating and damage the equipment" is specifically as follows:

[0085] Let the air flow of the auxiliary electric motor compressor 62 be W1, the rotation speed of the auxiliary motor 61 be N, the inlet pressure of the auxiliary electric motor compressor 62 be P0, the inlet temperature of the auxiliary electric motor compressor 62 be T0, and the characteristic constant of the auxiliary electric motor compressor 62 be K, which is related to the geometric size and efficiency of the auxiliary electric motor compressor 62.

[0086] Let the air flow of the sealing gas path 8 be W2, and the inlet flow of the auxiliary combustion chamber 63 be W3, then W3 = W1 - W2.

[0087] Let the fuel flow of the auxiliary combustion chamber 63 be W4, the outlet flow temperature of the auxiliary electric motor compressor 62 be T1 (which can be measured or calculated by the existing conventional method), the temperature of the lubricating oil in the lubricating oil tank 2 be T2 (which can be measured), the temperature of the high-temperature gas be T4 (which can be measured), the fuel combustion efficiency be ξ, the fuel heat value be LHV, and the air constant-pressure specific heat capacity be C.

[0088] Then: W1 = K × N × P0 / T0 0.5 .

[0089] Then: T4 = T1 + W4 × ξ × LHV / W3 × C.

[0090] According to the measured N and T2, the fuel flow W4 is controlled to obtain the required T4.

[0091] When T2 is small, the fuel flow into the auxiliary combustion chamber 63 is increased to increase T4; when T2 gradually increases, the fuel flow into the auxiliary combustion chamber 63 is reduced to reduce T4; when T2 reaches the expected value, the auxiliary combustion device 6 is started, the auxiliary combustion chamber 63 is extinguished, and the engine is started normally. By controlling T4, the temperature in the auxiliary combustion chamber 63 is controlled, so that the high-temperature gas can quickly and fully heat the lubricating oil and the engine, while ensuring the safety of the combustion chamber and avoiding excessive temperature from causing ablation or affecting reliability.

[0092] The use control method of the self-preheating starting system further includes the following steps:

[0093] S50: Safety protection: a flame detector, an over-temperature sensor, and an over-pressure sensor are added in the self-preheating starting system, so that the system can immediately cut off the fuel supply of the auxiliary combustion chamber 63 when an abnormality occurs, and an alarm prompt is sent to the operator.

[0094] The above only describes the preferred embodiments of the present application and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A turbo-shaft engine self-preheating starting system under extremely cold conditions, characterized in that, The system comprises: a fuel tank (1) for supplying fuel, an oil tank (2) for supplying oil, an oil inlet circuit connected to the oil tank (2), an electric energy storage device (4), an engine core (5), a start-up auxiliary combustion device (6), and a control system connected to the engine core (5) and the start-up auxiliary combustion device (6); the input side of the start-up auxiliary combustion device (6) is connected to the fuel tank (1) and the electric energy storage device (4) respectively, so as to introduce part of the fuel from the fuel tank (1) and introduce part of the air under the driving of the electric energy storage device (4) to form high-pressure gas, and make the high-pressure gas and the introduced part of the fuel burn to generate high-temperature gas; the oil inlet circuit is connected to the output side of the start-up auxiliary combustion device (6), so that the generated high-temperature gas preheats the oil in the oil inlet circuit, and the output end of the oil inlet circuit is also connected to multiple bearing cavities of the engine core (5), so that the preheated oil enters the multiple bearing cavities of the engine core (5) to lubricate; the start-up auxiliary combustion device (6) comprises an auxiliary motor (61) connected to the electric energy storage device (4), an auxiliary electric-driven compressor (62) connected to the auxiliary motor (61), and an auxiliary combustion chamber (63) connected to the fuel tank (1), and the auxiliary motor (61) and the auxiliary electric-driven compressor (62) are connected to the control system respectively; the engine core (5) mainly comprises a compressor (51), a combustion chamber (52), and a turbine (53), and the multiple bearing cavities comprise an accessory drive bearing cavity, a compressor bearing cavity, and a turbine bearing cavity; the start-up auxiliary combustion device (6) further comprises a high-temperature gas passage (64) connected to the exhaust end of the auxiliary combustion chamber (63); the oil inlet circuit comprises an oil inlet main pipe (31), an auxiliary oil pump (32) arranged in the oil inlet main pipe (31), two oil inlet branch pipes connected to the output end of the oil inlet main pipe (31), an oil inlet end of the oil inlet main pipe (31) connected to the oil tank (2), an oil outlet end of the oil inlet main pipe (31) extends out after passing through the high-temperature gas passage (64), and oil outlet ends of the two oil inlet branch pipes are connected to the compressor bearing cavity and the turbine bearing cavity respectively; the self-preheating start-up system further comprises an oil return circuit, the oil return circuit comprises two oil return branch pipes, an oil return main pipe (71) connected to oil outlet ends of the two oil return branch pipes, and an oil return pump (72) arranged in the oil return main pipe (71), oil inlet ends of the two oil return branch pipes are connected to the compressor bearing cavity and the turbine bearing cavity respectively, and an oil outlet end of the oil return main pipe (71) is communicated with the oil tank (2).

2. The self-preheating start-up system of the turboshaft engine under extremely cold conditions according to claim 1, wherein the auxiliary motor (61) is used to start under the action of the electric energy storage device (4) to drive the auxiliary electric-driven compressor (62) to rotate, and the auxiliary electric-driven compressor (62) is used to introduce air to form high-pressure gas after rotating, and then part of the high-pressure gas is input into the auxiliary combustion chamber (63); the auxiliary combustion chamber (63) is used to automatically ignite the mixed fuel of the introduced fuel and the high-pressure gas to generate high-temperature gas; the oil inlet circuit extends to the exhaust port of the auxiliary combustion chamber (63).

3. The self-preheating starting system for turboshaft engine under extremely cold conditions according to claim 2, characterized in that, the self-preheating starting system further comprises a seal gas circuit (8), the gas inlet end of the seal gas circuit (8) is connected to the gas outlet end of the auxiliary electric-driven air compressor (62), and the gas outlet end of the seal gas circuit (8) is connected to multiple bearing cavities of the engine core (5) for introducing high-pressure gas to seal and prevent oil leakage; the self-preheating starting system further comprises a bleed air circuit (9) and a switch valve arranged in the bleed air circuit (9), the switch valve is connected to the control system, the gas inlet end of the bleed air circuit (9) is connected to the high-temperature gas passage (64), and the gas outlet end of the bleed air circuit (9) is connected to the gas inlet of the compressor (51).

4. The self-preheating starting system for turboshaft engine under extremely cold conditions according to claim 2, characterized in that, the self-preheating starting system further comprises a fuel auxiliary flow circuit, a fuel main flow circuit and a fuel return circuit (12); the fuel auxiliary flow circuit comprises an auxiliary fuel pipe (101) connected to the fuel tank (1) and the auxiliary combustion chamber (63), and an auxiliary fuel pump arranged in the auxiliary fuel pipe (101), the auxiliary fuel pump being connected to the control system; the fuel main flow circuit comprises a main fuel pipe (111) connected to the fuel tank (1) and the combustion chamber (52), and a main fuel pump (112) arranged in the main fuel pipe (111), the main fuel pump (112) being connected to the control system, and the main fuel pipe (111) extending through the high-temperature gas passage (64); the gas inlet end of the fuel return circuit (12) is connected to the gas outlet end of the high-temperature gas passage (64), and the gas outlet end of the fuel return circuit (12) is connected to the storage device tank for mounting the storage device (4).

5. A control method for a self-preheating starting system of a turbo-shaft engine under extremely cold conditions, characterized in that, The self-preheating starting system for turboshaft engine under extremely cold conditions according to any one of claims 2-4 is used, and the control method of the self-preheating starting system comprises the following steps: system starting trigger: operator-initiated starting trigger or control system automatic starting trigger according to environmental temperature and / or engine state; combustion heating: starting the auxiliary combustion device (6) to introduce part of fuel, introduce part of air to form high-pressure gas, and make the high-pressure gas and the introduced fuel burn to generate high-temperature gas; heat transfer and distribution: using the high-temperature gas to preheat the lubricating oil, fuel and engine core (5), and to keep the storage device (4) warm; closed-loop control: multiple temperature sensors and multiple pressure sensors are added in the self-preheating starting system, the control system calculates and dynamically adjusts the fuel supply amount of the auxiliary combustion chamber (63) and the flow of high-pressure gas according to the preset optimal preheating temperature curve, and then accurately controls the combustion power in the auxiliary combustion chamber (63) and the temperature of the high-temperature gas discharged, so as to prevent overheating damage to the equipment.

6. The turboshaft engine self-preheating starting system use control method of claim 5, wherein, The step "combustion heating" specifically comprises the following steps: the control system controls the auxiliary fuel pump to extract a small amount of fuel from the fuel tank (1) and deliver it to the auxiliary combustion chamber (63); the storage device (4) controls the auxiliary electric-driven air compressor (62) to work to generate high-pressure gas, and the high-pressure gas is supplied to the auxiliary combustion chamber (63) for combustion and to multiple bearing cavities in the engine core (5) for sealing; The fuel and high pressure gas are mixed in the auxiliary combustion chamber (63) and ignited by an igniter to generate stable and controllable high temperature gas.

7. The control method of a self-preheating starting system of a turbo-shaft engine under extremely cold conditions according to claim 5, characterized in that, The step of "closed loop control" specifically comprises the following steps: A plurality of temperature sensors and a plurality of pressure sensors are added in the self-preheating starting system to monitor the temperature and pressure at multiple places in real time and feed back to the control system. The control system calculates and dynamically adjusts the fuel supply amount and high pressure gas flow of the auxiliary combustion chamber (63) according to the preset optimal preheating temperature curve, and then accurately controls the combustion power in the auxiliary combustion chamber (63) and the temperature of the high temperature gas discharged, so as to prevent overheating and damage the equipment. After preheating, the engine starts normally: When the control system monitors that the oil temperature and the engine core (5) metal temperature have reached the preset safe starting value, the control system automatically closes the starting auxiliary combustion device (6); Then the control system controls the engine to start according to the standard normal starting program.

8. The control method for the self-preheating starting system of the turbo-shaft engine under extremely cold conditions according to claim 7, characterized in that, The step of "the control system calculates and dynamically adjusts the fuel supply amount and high pressure gas flow of the auxiliary combustion chamber (63) according to the preset optimal preheating temperature curve, and then accurately controls the combustion power in the auxiliary combustion chamber (63) and the temperature of the high temperature gas discharged, so as to prevent overheating and damage the equipment" is specifically as follows: Let the air flow of the auxiliary electric compressor (62) be W1, the speed of the auxiliary motor (61) be N, the inlet pressure of the auxiliary electric compressor (62) be P0, the inlet temperature of the auxiliary electric compressor (62) be T0, and the characteristic constant of the auxiliary electric compressor (62) be K, which is related to the geometric size and efficiency of the auxiliary electric compressor (62); Let the air flow of the sealing gas path (8) be W2, and the inlet flow of the auxiliary combustion chamber (63) be W3, then W3=W1-W2; Let the fuel flow of the auxiliary combustion chamber (63) be W4, the outlet gas flow temperature of the auxiliary electric compressor (62) be T1, the oil temperature in the oil tank (2) be T2, the high temperature gas temperature be T4, the fuel combustion efficiency be ξ, the fuel heat value be LHV, and the air constant pressure specific heat capacity be C; W1 = K x N x P0 / T0 0.5 ; Then T4=T1+(W4×ξ×LHV) / (W3×C); According to the measured N and T2, the fuel flow W4 is controlled to obtain the required T4.

9. The turboshaft engine auto-start system control method of claim 5, wherein, The control method for the self-preheating starting system further comprises the following steps: Safety protection: flame detectors, over-temperature sensors and over-pressure sensors are added in the self-preheating starting system to immediately cut off the fuel supply of the auxiliary combustion chamber (63) when an abnormality occurs, and to send an alarm prompt to the operator.

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