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

Abstract

The invention discloses a self-preheating starting system for a turboshaft engine under an extremely cold condition and a use control method. The self-preheating starting system comprises a fuel tank, a lubricating oil tank, a lubricating oil inlet loop connected with the lubricating oil tank, an electricity storage device, an engine core engine, a starting auxiliary combustion device and a control system. The starting auxiliary combustion device is used for introducing part of fuel oil from the fuel tank, introducing part of air under driving of the electricity storage device to be pressurized to form high-pressure gas, and enabling the high-pressure gas and the fuel oil to be combusted to generate high-temperature fuel gas. The lubricating oil inlet loop is connected to the output side of the starting auxiliary combustion device so that high-temperature fuel gas can preheat lubricating oil in the lubricating oil inlet loop, and the output end of the lubricating oil inlet loop is further connected into multiple bearing cavities of the engine core machine so that the preheated lubricating oil can enter the multiple bearing cavities of the engine core machine to be lubricated. According to the system, fuel of an engine is used as energy, and lubricating oil and a core engine of the engine are accurately and rapidly preheated through a set of built-in efficient combustion heating system.

Description

Technical Field

[0001] This invention relates to the field of turboshaft engine technology, and in particular, to a self-preheating start-up system for turboshaft engines under extremely cold conditions. Furthermore, this invention also relates to a control method for using the aforementioned self-preheating start-up system for turboshaft engines under extremely cold conditions. Background Technology

[0002] Turboshaft engines are prone to starting problems or failure to start in extremely cold environments (such as -40°C or even lower) due to factors such as viscous lubricating oil, reduced rotor-stator clearance, and battery performance degradation under extreme cold conditions. Specifically: 1. Lubricating oil solidification problem: At low temperatures, the viscosity of engine lubricating oil increases sharply and may even solidify, resulting in huge resistance torque of friction pairs such as main shaft bearings, insufficient starter torque, and inability to drive the engine to ignition speed; 2. Stator-rotor clearance issues: Cold contraction of metal components may cause changes in dynamic clearances (such as blade tip clearance), which in turn affects aerodynamic performance and may even cause rubbing; at the same time, the cold brittleness of the material increases, posing a risk of damage under huge starting loads; 3. Sudden drop in battery performance: Low temperatures cause a severe decrease in battery capacity and voltage output, making it unable to provide a continuous and stable power supply to the starter and control system, resulting in interruption during the starting process; 4. Poor fuel atomization: Although aviation fuel has a low freezing point, its viscosity is too high at low temperatures, which may lead to poor atomization quality and affect ignition and initial combustion stability.

[0003] In the aviation field, especially for turboshaft engines used in helicopters and drones, the deployment environment is becoming increasingly harsh. Polar scientific expeditions, high-latitude rescue operations, and winter military operations all require engines to have reliable starting capabilities at extremely low temperatures. Currently, the most common approach is a combination of an external ground power vehicle (GPU) and an external hot air heating vehicle.

[0004] 1. External Ground Power Vehicle (GPU): Provides a large, high-power external power source to replace or assist the onboard battery, providing sufficient power to the starter motor to overcome the problems of high starter motor load and poor battery performance at low temperatures; 2. External hot air heating vehicle: This is a large, independent piece of equipment. It is equipped with a burner and a high-power fan. When it is working, it draws in air from the environment, heats it (usually by burning fuel) to produce high-temperature, high-flow-rate hot air. The hot air is connected to the aircraft's engine bleed air pipe or a special insulation jacket through a dedicated flexible pipe to externally heat the engine core (such as the compressor and combustion chamber section). At the same time, it also provides auxiliary heating for the engine's lubricating oil system.

[0005] Existing solutions involve providing additional energy (electricity and heat) through external devices to forcibly raise the temperature of the engine and lubrication system to bring them into the starting temperature range. The disadvantages of each approach are as follows: 1. Reliance on large external equipment: Dedicated power supply vehicles and hot air heating vehicles must be equipped. These devices are bulky, expensive, and require specialized transport vehicles (such as trucks) to transport them to the work site, which is difficult to guarantee in remote polar regions or forward airfields. 2. Complex and time-consuming process: Ground staff need to complete a series of complex processes such as equipment docking and preheating. The entire preheating process may take tens of minutes to several hours, making it impossible to start up quickly in an emergency, which seriously reduces the flexibility and response speed of the mission. 3. Poor portability: This solution is completely unsuitable for use in field sites or unmanned helicopters where ground support is lacking; 4. Low energy efficiency: During the process of heating the ambient air, most of the heat in the hot air heating vehicle is lost into the atmosphere, and the proportion of heat actually used to heat the engine is low, resulting in serious energy waste. 5. Safety risks exist: The high-temperature hot air ducts pose a risk of burns to personnel or damage to onboard equipment; the hot air heating vehicle itself is also a source of fire, and extra caution is required in flammable and explosive environments. Summary of the Invention

[0006] This invention provides a self-preheating start-up system and control method for turboshaft engines under extremely cold conditions. It addresses the shortcomings of existing methods that rely on external equipment for additional energy, which are difficult to guarantee in remote polar regions or forward airports, cannot achieve rapid emergency start-up, severely reduce mission flexibility and response speed, cannot be applied to field sites or unmanned helicopters lacking ground support, result in serious energy waste, pose a risk of burns to personnel or damage to onboard equipment due to high-temperature hot air ducts, and the hot air heating vehicle itself is also a source of fire, requiring extra caution in flammable and explosive environments.

[0007] The technical solution adopted in this invention is as follows: A self-preheating start-up system for a turboshaft engine under extremely cold conditions includes: a fuel tank for supplying fuel, an oil tank for supplying lubricating oil, an oil inlet circuit connected to the oil tank, a power storage device for storing electrical energy, an engine core, a starting auxiliary combustion device, and a control system connecting the engine core and the starting auxiliary combustion device. The input side of the starting auxiliary combustion device is connected to the fuel tank and the power storage device, respectively, for introducing a portion of fuel from the fuel tank, and simultaneously introducing a portion of air under the drive of the power storage device to pressurize it into high-pressure gas, and then burning the high-pressure gas with the introduced portion of fuel to generate high-temperature combustion gas. The oil inlet circuit is connected to the output side of the starting auxiliary combustion device, so that the generated high-temperature combustion gas preheats the lubricating oil in the oil inlet circuit. The output end of the oil inlet circuit is also connected to multiple bearing cavities of the engine core, so that the preheated lubricating oil enters the multiple bearing cavities of the engine core for lubrication.

[0008] Furthermore, the starting auxiliary combustion device includes an auxiliary motor connected to the energy storage device, an auxiliary electric compressor connected to the auxiliary motor, and an auxiliary combustion chamber connected to the fuel tank. The auxiliary motor and the auxiliary electric compressor are respectively connected to the control system. The auxiliary motor is used to start the auxiliary electric compressor under the action of the energy storage device to drive the auxiliary electric compressor to rotate. After the auxiliary electric compressor rotates, air is introduced and pressurized to form high-pressure gas, and part of it is input into the auxiliary combustion chamber. The auxiliary combustion chamber is used for automatic ignition to mix and burn the introduced fuel and high-pressure gas to produce high-temperature gas. The lubricating oil inlet circuit extends to the exhaust port passing through the auxiliary combustion chamber.

[0009] Furthermore, the core engine mainly includes a compressor, a combustion chamber, and a turbine, with multiple bearing cavities including accessory drive bearing cavities, compressor bearing cavities, and turbine bearing cavities; the starting auxiliary combustion device also includes a high-temperature gas passage connected to the exhaust end of the auxiliary combustion chamber; the lubricating oil inlet circuit includes a main lubricating oil inlet pipe, an auxiliary lubricating oil pump installed in the main lubricating oil inlet pipe, and two branch lubricating oil inlet pipes connected to the output end of the main lubricating oil inlet pipe. The inlet end of the main lubricating oil inlet pipe is connected to the oil tank, and the outlet of the main lubricating oil inlet pipe... After passing through a high-temperature gas passage, the end extends out, and the oil outlets of the two lubricating oil inlet branch pipes are respectively connected to the compressor bearing cavity and the turbine bearing cavity; the self-preheating start-up system also includes a lubricating oil return circuit, which includes two lubricating oil return branch pipes, a lubricating oil return main pipe connecting the oil outlets of the two lubricating oil return branch pipes, and a lubricating oil return pump installed in the lubricating oil return main pipe. The 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 the oil outlet end of the lubricating oil return main pipe is connected to the lubricating oil tank.

[0010] Furthermore, the self-preheating start-up system also includes a sealing air passage. The inlet end of the sealing air passage is connected to the exhaust end of the auxiliary electric compressor, and the exhaust end of the sealing air passage is connected to multiple bearing cavities of the engine core to introduce high-pressure air for sealing and preventing oil leakage. The self-preheating start-up system also includes a ducting air passage and a switching valve installed in the ducting air passage. The switching valve is connected to the control system. The inlet end of the ducting air passage is connected to the high-temperature gas passage, and the outlet end of the ducting air passage is connected to the compressor inlet.

[0011] Furthermore, the self-preheating start-up system also includes a fuel auxiliary flow path, a fuel main flow path, and a gas return path; the fuel auxiliary flow path includes an auxiliary fuel pipe connecting the fuel tank and the auxiliary combustion chamber, and an auxiliary fuel pump installed in the auxiliary fuel pipe, the auxiliary fuel pump being connected to the control system; the fuel main flow path includes a main fuel pipe connecting the fuel tank and the combustion chamber, and a main fuel pump installed in the main fuel pipe, the main fuel pump being connected to the control system, the main fuel pipe extending to a high-temperature gas passage; the intake end of the gas return path is connected to the exhaust end of the high-temperature gas passage, and the exhaust end of the gas return path is connected to the gas storage box for installing the gas storage device.

[0012] According to another aspect of the present invention, a control method for a self-preheating start-up system of a turboshaft engine under extremely cold conditions is also provided. The self-preheating start-up system of a turboshaft engine under extremely cold conditions, as described in any of the above, includes the following steps: System start-up triggering: The operator actively initiates the triggering, or the control system automatically initiates the triggering based on the ambient temperature and / or engine status; Combustion heating: A starting auxiliary combustion device is activated to introduce a portion of fuel, and simultaneously a portion of air is introduced to pressurize and form high-pressure gas, which is then combusted with the introduced fuel to produce high-temperature gas; Heat transfer and distribution: The high-temperature gas is used to preheat the lubricating oil, fuel, and engine core, and to insulate the energy storage device; Closed-loop control: Multiple temperature sensors and multiple pressure sensors are added to the self-preheating start-up system, enabling the control system to calculate and dynamically adjust the fuel supply and high-pressure gas flow rate in the auxiliary combustion chamber according to a preset optimal preheating temperature curve, thereby precisely controlling the combustion power in the auxiliary combustion chamber and the temperature of the discharged high-temperature gas to prevent overheating and equipment damage.

[0013] Furthermore, the "combustion heating" step specifically includes the following steps: the control system controls the auxiliary fuel pump to draw a small amount of fuel from the fuel tank and deliver it to the auxiliary combustion chamber; the accumulator 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 path, and to multiple bearing cavities in the engine core for sealing in another path; the fuel and high-pressure gas mix in the auxiliary combustion chamber and are ignited by the igniter to produce stable and controllable high-temperature gas.

[0014] Furthermore, the "closed-loop control" step specifically includes the following steps: Multiple temperature and pressure sensors are added to the self-preheating start-up system to monitor multiple temperatures and pressures in real time and provide feedback to the control system; the control system calculates and dynamically adjusts the fuel supply and high-pressure gas flow in the auxiliary combustion chamber based on a preset optimal preheating temperature curve, thereby precisely controlling the combustion power and the temperature of the discharged high-temperature gas in the auxiliary combustion chamber to prevent overheating and equipment damage. After preheating is complete, the engine starts normally: when the control system detects that the lubricating oil temperature and the engine core metal temperature have both reached the preset safe starting values, the control system automatically shuts off the starting auxiliary combustion device; subsequently, the control system controls the engine to start according to the standard normal starting procedure.

[0015] Further, the step "the control system calculates and dynamically adjusts the fuel supply and high-pressure gas flow rate of the auxiliary combustion chamber according to the preset optimal preheating temperature curve, thereby precisely controlling the combustion power and the temperature of the discharged high-temperature gas in the auxiliary combustion chamber to prevent overheating and damage to the equipment" is as follows: Let the air flow rate of the auxiliary electric compressor be W1, the speed of the auxiliary motor be N, the intake pressure of the auxiliary electric compressor be P0, the intake temperature of the auxiliary electric compressor be T0, and the characteristic constant of the auxiliary electric compressor be K (geometric dimensions and efficiency related). Let the air flow rate of the sealed air circuit be W2, and the intake flow rate of the auxiliary combustion chamber be W3, then W3 = W1 - W2; Let the fuel flow rate of the auxiliary combustion chamber be W4, the outlet gas temperature of the auxiliary electric compressor be T1, the lubricating oil temperature in the lubricating oil tank be T2, the high-temperature gas temperature be T4, the fuel combustion efficiency be ξ, the fuel calorific 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); Based on the measured N and T2, the required T4 is obtained by controlling the fuel flow rate W4.

[0016] Furthermore, the control method for the self-preheating start system also includes the following steps: Safety protection: A flame detector, an over-temperature sensor, and an over-pressure sensor are added to the self-preheating start system so that the control system can immediately cut off the fuel supply to the auxiliary combustion chamber in the event of an abnormality, and at the same time issue an alarm to the operator.

[0017] The present invention has the following beneficial effects: The self-preheating starting system of this invention is a highly integrated, self-sufficient starting system for extremely cold conditions. Its core idea is to utilize the engine's own fuel as an energy source, and through a built-in high-efficiency combustion heating system (referring to the starting auxiliary combustion device), to accurately and rapidly preheat the engine oil and core components, as detailed below: 1. Integrated design: The combustion heating system and control system are highly integrated in or near the engine accessory housing, without relying on any external equipment. Therefore, the overall system is small in size, highly portable, and requires no ground support. It can be applied to any aircraft that deploys this engine, including unmanned helicopters, and is also suitable for remote polar regions or forward airports. 2. It uses its own fuel as an energy source: it achieves energy self-sufficiency and has a high energy utilization rate; 3. Intelligent closed-loop control: Unified control by the engine control system enables fully autonomous starting capability in extremely cold conditions without ground support; it achieves a fully automatic, safe, and efficient preheating process, which can significantly shorten preparation time, improve mission response capability and response flexibility; it also simplifies operation procedures, reduces human error, and improves safety.

[0018] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the self-preheating start-up system of a turboshaft engine under extremely cold conditions, according to a preferred embodiment of the present invention.

[0020] Legend: 1. Fuel tank; 2. Lubricating oil tank; 31. Main oil inlet pipe; 32. Auxiliary oil pump; 4. Energy storage device; 5. Engine core; 51. Compressor; 52. Combustion chamber; 53. Turbine; 6. Starting auxiliary combustion device; 61. Auxiliary motor; 62. Auxiliary electric compressor; 63. Auxiliary combustion chamber; 64. High-temperature gas passage; 71. Main oil return pipe; 72. Oil return pump; 8. Sealed air passage; 9. Drainage air passage; 101. Auxiliary fuel line; 102. Auxiliary fuel pump; 111. Main fuel line; 112. Main fuel pump; 12. Gas return path. Detailed Implementation

[0021] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0022] Those skilled in the art will understand that, unless specifically stated otherwise, the term "comprising" as used in this specification means the presence of the stated features, integers, steps, operations, components, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, components, and / or combinations thereof. It should be understood that when we say a component is "connected" to another component, it can be directly connected to the other component or connected via an intermediate component. The term "and / or" as used herein includes all or any unit and all combinations of one or more associated listed items. The terms "first" and "second," etc., in this specification and claims are used to distinguish different objects, not to describe a particular order.

[0023] Reference Figure 1 A preferred embodiment of the present invention provides a self-preheating start-up system for a turboshaft engine under extremely cold conditions, comprising: a fuel tank 1 for supplying fuel, an oil tank 2 for supplying lubricating oil, an oil inlet circuit connected to the oil tank 2, a power storage device 4 for storing electrical energy, an engine core 5, a starting auxiliary combustion device 6, and a control system connecting the engine core 5 and the starting auxiliary combustion device 6. The input side of the starting auxiliary combustion device 6 is connected to both the fuel tank 1 and the power storage device 4, for introducing a portion of fuel from the fuel tank 1. Simultaneously, driven by the power storage device 4, a portion of air is introduced and pressurized to form high-pressure gas, which then combusts with the introduced portion of fuel to generate high-temperature combustion gas. The oil inlet circuit is connected to the output side of the starting auxiliary combustion device 6, so that the generated high-temperature combustion gas preheats the lubricating oil in the oil inlet circuit. The output end of the oil inlet circuit is also connected to multiple bearing cavities of the engine core 5, so that the preheated lubricating oil enters and lubricates these bearing cavities.

[0024] When the turboshaft engine self-preheating start-up system of the present invention operates under extremely cold conditions, the operator manually triggers or the system automatically triggers the start-up according to preset conditions. Fuel in fuel tank 1 enters the starting auxiliary combustion device 6, and simultaneously, outside air also enters the starting auxiliary combustion device 6 and is compressed into high-pressure gas under the action of the starting auxiliary combustion device 6. The high-pressure gas then mixes with fuel and combusts to form high-temperature combustion gas, which is output externally. At this time, the low-temperature lubricating oil in oil tank 2 is forcibly driven into the lubricating oil inlet circuit. When the low-temperature lubricating oil in the lubricating oil inlet circuit passes the output side of the starting auxiliary combustion device 6, it reacts with the high-temperature combustion gas. After heat exchange, the temperature rises rapidly. The heated lubricating oil then enters multiple bearing cavities of the engine core 5 under the action of the lubricating oil inlet circuit, "preheating" the bearings, gears and other components, and then flows back to the lubricating oil tank 2 to form a cycle. When the engine control system detects that the lubricating oil temperature and the core metal temperature have reached the preset safe starting value, the control system automatically shuts off the starting auxiliary combustion device 6. Subsequently, the control system controls the engine to start according to the standard normal starting procedure. At this time, due to the significant reduction in lubricating oil resistance, the power of the energy storage device 4 is sufficient to drive the starter motor, and the engine can smoothly reach the ignition speed and ignite successfully.

[0025] The self-preheating starting system of this invention is a highly integrated, self-sufficient starting system for extremely cold conditions. Its core idea is to utilize the engine's own fuel as an energy source and, through a built-in high-efficiency combustion heating system (referring to the starting auxiliary combustion device 6), precisely and rapidly preheat the engine oil and core components, as detailed below: 1. Integrated design: The combustion heating system and control system are highly integrated in or near the engine accessory housing, without relying on any external equipment. Therefore, the overall system is small in size, highly portable, and requires no ground support. It can be applied to any aircraft that deploys this engine, including unmanned helicopters, and is also suitable for remote polar regions or forward airports. 2. It uses its own fuel as an energy source: it achieves energy self-sufficiency and has a high energy utilization rate; 3. Intelligent closed-loop control: Unified control by the engine control system enables fully autonomous starting capability in extremely cold conditions without ground support; it achieves a fully automatic, safe, and efficient preheating process, which can significantly shorten preparation time, improve mission response capability and response flexibility; it also simplifies operation procedures, reduces human error, and improves safety.

[0026] Optionally, such as Figure 1As shown, the starting auxiliary combustion device 6 includes an auxiliary motor 61 connected to the energy storage device 4, an auxiliary electric compressor 62 connected to the auxiliary motor 61, and an auxiliary combustion chamber 63 connected to the fuel tank 1. 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 energy storage device 4 to drive the auxiliary electric compressor 62 to rotate. After the auxiliary electric compressor 62 rotates, it introduces air, pressurizes it to form high-pressure gas, and then partially inputs it into the auxiliary combustion chamber 63. The auxiliary combustion chamber 63 is used for automatic ignition to mix and burn the introduced fuel and high-pressure gas to produce high-temperature combustion gas. The lubricating oil inlet circuit extends to the exhaust port passing through the auxiliary combustion chamber 63. During operation, the power supply of the energy storage device 4 enables the auxiliary motor 61 to operate, and the auxiliary motor 61 drives the auxiliary electric compressor 62 to start. Outside air enters the auxiliary electric compressor 62 and is compressed into high-pressure gas after being acted upon by it. Part of this high-pressure gas enters the auxiliary combustion chamber 63. At the same time, part of the fuel in the fuel tank 1 also enters the auxiliary combustion chamber 63. After the high-pressure gas and fuel are ignited in the auxiliary combustion chamber 63, they are fully combusted to form high-temperature gas, which is discharged to the outside through the exhaust port of the auxiliary combustion chamber 63.

[0027] Optionally, such as Figure 1 As shown, the engine core 5 mainly includes a compressor 51, a combustion chamber 52, and a turbine 53, with multiple bearing cavities including an accessory drive bearing cavity, a compressor bearing cavity, and a turbine bearing cavity. The starting auxiliary combustion device 6 also includes a high-temperature gas passage 64 connected to the exhaust end of the auxiliary combustion chamber 63. The lubricating oil inlet circuit includes a main lubricating oil inlet pipe 31, an auxiliary lubricating oil pump 32 installed in the main lubricating oil inlet pipe 31, and two lubricating oil inlet branch pipes connected to the output end of the main lubricating oil inlet pipe 31. The inlet end of the main lubricating oil inlet pipe 31 is connected to the lubricating oil tank 2, and the outlet end of the main lubricating oil inlet pipe 31 extends out after passing through the high-temperature gas passage 64. The 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 start-up system also includes a lubricating oil return circuit, which includes two lubricating oil return branch pipes, a lubricating oil return main pipe 71 connecting the oil outlets of the two lubricating oil return branch pipes, and a lubricating oil return pump 72 installed in the lubricating oil return main pipe 71. The 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 the oil outlet end of the lubricating oil return main pipe 71 is connected to the lubricating oil tank 2. During operation, the low-temperature lubricating oil in the lubricating oil tank 2 enters the lubricating oil inlet main pipe 31 under the action of the auxiliary lubricating oil pump 32, and then enters the high-temperature gas passage 64 along with the lubricating oil inlet main pipe 31. After exchanging heat with the high-temperature gas in the high-temperature gas passage 64 and being heated, it enters the two lubricating oil inlet branch pipes, and then enters the compressor bearing cavity and the turbine bearing cavity respectively through the two lubricating oil inlet branch pipes to preheat the bearings and gears in the bearing cavities. Then, under the action of the lubricating oil return pump 72, the lubricating oil that has preheated the bearings and gears enters the lubricating oil return main pipe 71 through the two lubricating oil return branch pipes, and finally flows back to the lubricating oil tank 2 through the lubricating oil return main pipe 71 to form a lubricating oil circulation.

[0028] Optionally, such as Figure 1 As shown, the self-preheating start-up system also includes a sealing air passage 8. The inlet end of the sealing air passage 8 is connected to the exhaust end of the auxiliary electric compressor 62, and the exhaust end of the sealing air passage 8 is connected to multiple bearing cavities of the engine core 5 to introduce high-pressure air for sealing and preventing oil leakage. Specifically, the sealing air passage 8 enters the accessory drive bearing cavity, compressor bearing cavity, and turbine bearing cavity through multiple air passage branches. The oil leakage prevention principle of the engine core is to establish a slightly higher pressure air zone along the path where lubricating oil may leak, and use the pressure difference to "push" the lubricating oil back or block it in the area where it should be. During normal engine operation, high-pressure air is generally drawn from the engine's compression components for sealing / preventing oil leakage. However, in the initial stage of engine start-up or preheating, the compression components have not yet formed high-pressure air, making it difficult to seal effectively. At this time, the high-pressure air generated by the auxiliary electric compressor 62 in this invention can be used for sealing. During operation, after the auxiliary electric compressor 62 is started, outside air enters it and is compressed by the auxiliary electric compressor 62 to form high-pressure gas. At this time, one path of high-pressure gas enters the auxiliary combustion chamber 63, mixes with fuel and burns to form high-temperature gas. Another path of high-pressure gas passes through the sealed gas passage 8 as needed, and flows through the main gas passage and multiple gas passage branches to multiple bearing cavities and other locations in the engine core 5 that require sealing.

[0029] Optionally, such as Figure 1 As shown, the self-preheating start-up system also includes a duct flow path 9 and a switching valve installed in the duct flow path 9. The switching valve is connected to the control system. The inlet end of the duct flow path 9 is connected to the high-temperature gas passage 64, and the outlet end of the duct flow path 9 is connected to the inlet of the compressor 51. During operation, the high-temperature gas in the high-temperature gas passage 64 is also partially introduced into the inlet of the compressor 51 of the engine core engine 5 through a pipe with a controllable valve, namely the duct flow path 9, to gently heat the engine core engine 5.

[0030] Optionally, such as Figure 1As shown, the self-preheating start-up system also includes a fuel auxiliary flow path, a fuel main flow path, and a gas return path 12. The fuel auxiliary flow path includes an auxiliary fuel pipe 101 connecting the fuel tank 1 and the auxiliary combustion chamber 63, and an auxiliary fuel pump 102 installed in the auxiliary fuel pipe 101. The auxiliary fuel pump 102 is connected to the control system. During operation, the auxiliary fuel pump 102 supplies a portion of the fuel in the fuel tank 1 into the auxiliary combustion chamber 63 through the auxiliary fuel pipe 101. The main fuel path includes a main fuel pipe 111 connecting the fuel tank 1 and the combustion chamber 52, and a main fuel pump 112 installed in the main fuel pipe 111. The main fuel pump 112 is connected to the control system. The main fuel pipe 111 extends to a high-temperature gas passage 64. During operation, the fuel in the fuel tank 1 enters the main fuel pipe 111 under the action of the main fuel pump 112. After passing through the high-temperature gas passage 64, the fuel exchanges heat with the high-temperature gas and is then supplied to the combustion chamber 52 through the main fuel pipe 111. This preheats the fuel with high-temperature gas, improves the fuel atomization effect, and ensures the stability of ignition and initial combustion. The inlet of the gas return path 12 is connected to the exhaust of the high-temperature gas passage 64, and the exhaust of the gas return path 12 is connected to the storage box for installing the storage device 4. During operation, a stream of warm air from the high-temperature gas passage 64 is guided to the storage box through the gas return path 12 to prevent the performance of the storage device 4 from degrading due to low temperature. The storage device 4, which is generally a battery, provides a continuous, stable and powerful power to the starter and control system, ensuring a smooth starting process.

[0031] Reference Figure 1 A preferred embodiment of the present invention also provides a control method for the use of a self-preheating start-up system for a turboshaft engine under extremely cold conditions. The self-preheating start-up system for a turboshaft engine under extremely cold conditions, as described above, is used. The control method for the use of the self-preheating start-up system includes the following steps: S10: System start-up trigger: Operator-initiated start-up trigger, or automatic start-up trigger by the control system based on ambient temperature and / or engine status; S20: Combustion heating: Start the auxiliary combustion device 6 to introduce some fuel oil and at the same time introduce some air to pressurize and form high-pressure gas, and make the high-pressure gas and the introduced fuel oil burn to produce high-temperature gas. S30: Heat transfer and distribution: using high-temperature gas to preheat lubricating oil, fuel and engine core 5, and to insulate the energy storage device 4; S40: Closed-loop control: Multiple temperature sensors and multiple pressure sensors are added to the self-preheating start-up 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, thereby accurately controlling the combustion power in the auxiliary combustion chamber 63 and the temperature of the discharged high-temperature gas to prevent overheating and damage to the equipment.

[0032] The self-preheating start-up system of this invention uses a control method that is uniformly controlled by the engine control system to achieve fully autonomous start-up capability in extremely cold conditions without ground support. It can be applied to any aircraft that deploys this engine, including unmanned helicopters. It also realizes a fully automatic, safe, and efficient preheating process, which can significantly shorten preparation time and improve mission response capability and response flexibility. At the same time, it simplifies the operation process, reduces human error, and improves safety.

[0033] Optionally, step "S10: System Start-up Trigger" specifically involves the pilot or flight control computer issuing a low-temperature start-up command; the engine control system detects the ambient temperature and engine status, and if it is lower than a set threshold (e.g., -20°C), it automatically activates the self-preheating start-up system of the present invention.

[0034] Optionally, step "S20: Combustion Heating" specifically includes the following steps: S201: The control system controls the auxiliary fuel pump 102 to draw a small amount of fuel from the fuel tank 1 and deliver it to the auxiliary combustion chamber 63; S202: The energy storage device 4 controls the auxiliary electric compressor 62 to work to generate high-pressure gas, and supplies one path of high-pressure gas to the auxiliary combustion chamber 63 to participate in combustion, and another path to supply multiple bearing cavities in the engine core 5 for sealing. S203: Fuel oil 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.

[0035] Specifically, a small auxiliary electric compressor 62 (powered by an onboard battery) starts working. Outside air enters the auxiliary electric compressor 62 and is compressed by the auxiliary electric compressor 62 to form high-pressure gas. At this time, one path of high-pressure gas enters the auxiliary combustion chamber 63, mixes with fuel and burns to form high-temperature gas. Another path of high-pressure gas passes through the sealed air passage 8 as needed, and flows through the bleed pipe to the engine bearing cavity and other places that need to be sealed.

[0036] Optionally, step "S30: Heat Transfer and Distribution" specifically includes the following: Lubricating oil preheating circuit: The low-temperature lubricating oil of the engine is forcibly driven by an auxiliary lubricating oil pump 32. When it flows through the exhaust side of the auxiliary combustion chamber 63, it absorbs the heat of the high-temperature gas and the temperature rises rapidly. The heated lubricating oil flows back to the engine lubricating oil system to "preheat" the bearings, gears and other components. Fuel preheating circuit: heats the fuel in the fuel line between the helicopter fuel tank 1 and the engine to improve fuel atomization quality; Core engine preheating circuit: High-temperature combustion gas is introduced slightly into the compressor inlet of the engine through a controllable valve duct 9 to gently heat the engine core engine 5; Battery insulation: Guides warm air into the battery compartment to prevent battery performance from deteriorating due to low temperatures.

[0037] Therefore, the system of the present invention can simultaneously preheat lubricating oil, fuel, engine core 5, and battery in a differentiated manner, resulting in high energy utilization.

[0038] Optionally, step "S40: Closed-loop control" specifically includes the following steps: S401: Multiple temperature sensors and multiple pressure sensors are added to the self-preheating start-up system to monitor multiple temperatures and pressures in real time and feed them back to the control system; specifically: the system has multiple built-in temperature sensors and pressure sensors to monitor the lubricating oil outlet temperature and pressure, core engine preheating hot spot temperature, combustion chamber temperature, etc. in real time. S402: The control system calculates and dynamically adjusts the fuel supply and high-pressure gas flow rate of the auxiliary combustion chamber 63 according to the preset optimal preheating temperature curve, thereby accurately controlling the combustion power and the temperature of the discharged high-temperature gas in the auxiliary combustion chamber 63 to prevent overheating and damage to the equipment. S403: Preheating complete, engine starts normally. When the control system detects that the lubricating oil temperature and the core metal temperature of the engine 5 have both reached the preset safe starting value, the control system automatically shuts down the starting auxiliary combustion device 6.

[0039] The control system then starts the engine according to the standard normal starting procedure.

[0040] In this optional scheme, step "S402: The control system calculates and dynamically adjusts the fuel supply and high-pressure gas flow rate of the auxiliary combustion chamber 63 according to the preset optimal preheating temperature curve, thereby precisely controlling the combustion power and the temperature of the discharged high-temperature gas in the auxiliary combustion chamber 63 to prevent overheating and damage to the equipment" is as follows: Let the air flow rate 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 dimensions and efficiency of the auxiliary electric compressor 62.

[0041] Let the air flow rate of the sealed air passage 8 be W2, and the air flow rate of the auxiliary combustion chamber 63 be W3, then W3 = W1 - W2.

[0042] Let the fuel flow rate of the auxiliary combustion chamber 63 be W4, the outlet gas flow temperature of the auxiliary electric compressor 62 be T1 (which can be measured or calculated using existing conventional methods), the lubricating oil temperature in the lubricating oil tank 2 be T2 (which can be measured), and the engine core temperature 5, the high-temperature gas temperature be T4 (which can be measured), the fuel combustion efficiency be ξ, the fuel calorific value be LHV, and the air constant pressure specific heat capacity be C.

[0043] Then: W1 = K × N × P0 / T0 0.5 .

[0044] Then T4 = T1 + W4 × ξ × LHV / W3 × C.

[0045] Based on the measured N and T2, the required T4 is obtained by controlling the fuel flow rate W4.

[0046] When T2 is low, the fuel supply flow into the auxiliary combustion chamber 63 is increased, causing T4 to rise. As T2 gradually rises, the fuel supply flow into the auxiliary combustion chamber 63 is decreased accordingly, causing T4 to decrease. When T2 reaches the expected value, the auxiliary combustion device 6 is activated, the auxiliary combustion chamber 63 is shut down, and the engine starts normally. By controlling T4, the temperature in the auxiliary combustion chamber 63 is controlled, ensuring that the high-temperature combustion gas rapidly and fully heats the lubricating oil and the engine while maintaining combustion chamber safety and preventing excessive temperature from causing erosion or affecting reliability.

[0047] The control method for using a self-preheating start-up system also includes the following steps: S50: Safety protection: A flame detector, an over-temperature sensor, and an over-pressure sensor are added to the self-preheating start-up system so that the control system can immediately cut off the fuel supply to the auxiliary combustion chamber 63 in the event of an abnormality, and at the same time issue an alarm to the operator.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

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 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, so as to introduce part of the fuel from the fuel tank (1) and introduce part of the air under the drive 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 starting 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.

2. The self-preheating starting system for the turboshaft engine under extremely cold conditions according to claim 1, wherein the starting 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 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 the turboshaft engine under extremely cold conditions according to claim 2, wherein 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 starting 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) extending out after passing through the high-temperature gas passage (64), and oil outlet ends of the two oil inlet branch pipes connected to the compressor bearing cavity and the turbine bearing cavity respectively. The self-preheating starting system further comprises a lubricating oil return circuit, the lubricating oil return circuit comprises two lubricating oil return branches, a lubricating oil return main pipe (71) connected to the outlet ends of the two lubricating oil return branches, and a lubricating oil return pump (72) arranged in the lubricating oil return main pipe (71), the inlet ends of the two lubricating oil return branches are connected to the compressor bearing cavity and the turbine bearing cavity respectively, and the outlet end of the lubricating oil return main pipe (71) is communicated with the lubricating oil tank (2).

4. The self-preheating starting system for turbo-shaft engine under extremely cold conditions according to claim 3, characterized in that, The self-preheating starting system further comprises a sealing gas circuit (8), the inlet end of the sealing gas circuit (8) is communicated with the outlet end of the auxiliary electric compressor (62), and the outlet end of the sealing 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 inlet end of the bleed air circuit (9) is communicated with the high-temperature gas passage (64), and the outlet end of the bleed air circuit (9) is connected to the inlet of the compressor (51).

5. The self-preheating starting system for turbo-shaft engine under extremely cold conditions according to claim 3, 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 inlet end of the fuel return circuit (12) is connected to the outlet end of the high-temperature gas passage (64), and the outlet end of the fuel return circuit (12) is connected to the storage device tank for mounting the storage device (4).

6. 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 turbo-shaft engine under extremely cold conditions according to any one of claims 3-5 uses a control method comprising the following steps: System starting trigger: operator-initiated starting trigger or automatic starting trigger by the control system according to the environmental temperature and / or engine state; Combustion heating: the auxiliary combustion device (6) introduces part of the fuel, at the same time, 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 gas; Heat transfer and distribution: uses 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: adds multiple temperature sensors and multiple pressure sensors in the self-preheating starting system, so that the control system calculates and dynamically adjusts the fuel supply amount of the auxiliary combustion chamber (63) and the flow of the 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 and damage the equipment.

7. The control method of a self-preheating starting system of a turbo-shaft engine under extremely cold conditions according to claim 6, characterized in that, The step "combustion heating" specifically comprises the following steps: The control system controls the auxiliary fuel pump to draw a small amount of fuel from the fuel tank (1) and deliver it to the auxiliary combustion chamber (63); 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) to participate in combustion and to the 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 the igniter to generate stable and controllable high-temperature gas.

8. The control method for the self-preheating starting system of the turbo-shaft engine under extremely cold conditions according to claim 6, characterized in that, The step "closed-loop control" specifically includes the following steps: A plurality of temperature sensors and a plurality of pressure sensors are added to the self-preheating starting system to monitor the temperatures and pressures at multiple locations 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 (63) 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 (63) and the temperature of the high-temperature gas discharged, so as to prevent overheating and damage to the equipment; After preheating, the engine is started 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.

9. The control method for the self-preheating starting system of the turbo-shaft engine under extremely cold conditions according to claim 8, characterized in that, The step "the control system calculates and dynamically adjusts the fuel supply amount of the auxiliary combustion chamber (63) 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 (63) and the temperature of the high-temperature gas discharged, so as to prevent overheating and damage to 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 (which also represents the temperature of the engine core (5)), 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.

10. The turboshaft engine auto-start system control method of claim 6, wherein, The control method for the self-preheating starting system further includes the following steps: Safety protection: flame detectors, over-temperature sensors and over-pressure sensors are added to the self-preheating starting system, so that when an abnormality occurs, the control system immediately cuts off the fuel supply to the auxiliary combustion chamber (63) and sends an alarm prompt to the operator.

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