High-altitude rapid electric starting method for micro turbojet engine

Abstract

The application discloses a high-altitude rapid electric starting method for a micro turbojet engine, and realizes rapid and reliable starting of the turbojet engine under high-altitude and low-temperature conditions through measures such as segmented fuel control and rotating speed control, dynamic calculation of fuel flow in an accelerating stage, fuel flow temperature compensation correction and the like. The application has the outstanding advantages of low cost and convenient implementation, and has high reference significance and popularization space in the related field.

Description

Technical Field

[0001] This invention belongs to the field of engine technology, specifically relating to a method for rapid electric starting of a micro turbojet engine at high altitude. Background Technology

[0002] A turbojet engine is a type of turbine engine that uses a centrifugal impeller to compress air, which is then mixed with atomized fuel and combusted to generate thrust. Micro turbojet engines typically refer to those with a thrust of less than 50 kg. Starting methods mainly include pyrotechnic starting and electric starting. Pyrotechnic starting requires a pyrotechnic igniter and a propellant starter installed on the engine block. The pyrotechnic igniter ignites the fuel in the combustion chamber, rapidly increasing the combustion chamber temperature. The propellant starter then rotates the turbine to quickly reach operating speed. This starting method increases the size, weight, and cost of the turbojet engine, and the number of starts is strictly limited, typically 3-5 times.

[0003] Turbojet engines have low electric starting costs and are convenient to use in plains areas. They require appropriate speed and fuel control strategies to gradually increase the engine's combustion chamber temperature and turbine speed. However, high-altitude and high-velocity environments bring harsh conditions such as low temperatures and lack of oxygen, making it difficult for turbojet engines to ignite. Fuel-air mismatch during the starting process leads to frequent engine shutdowns. Conventional electric starting turbojet engines cannot start independently and reliably, and require the use of methane and compressed air to assist in increasing the combustion chamber temperature and turbine speed. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a method for rapid electric starting of a micro turbojet engine at high altitude. This method achieves rapid and reliable starting of the turbojet engine under high-altitude, low-temperature conditions through measures such as segmented fuel control and speed control, dynamic calculation of fuel flow during acceleration, and fuel flow temperature compensation correction. The outstanding advantages of this invention are low cost and ease of implementation, making it highly valuable for reference and widespread application in related fields.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows: Step 1: The fuel pump of the turbojet engine supplies fuel to both the main fuel line and the ignition fuel line simultaneously. The main fuel line and the ignition fuel line are each controlled by a solenoid valve to open and close the fuel lines. The ignition fuel line leads to the electric ignition head, and the main fuel line leads to the combustion chamber evaporator. The turbojet engine is equipped with a temperature sensor and a speed sensor to collect the exhaust temperature and speed of the turbojet engine in real time. Step 2: Ignition stage; Step 3: Preheating stage; Step 4: Acceleration Phase; Step 5: Execution phase; Step 6: Fuel flow temperature compensation correction.

[0006] Preferably, step 2 specifically comprises: Step 2-1: After entering the ignition process, the electric igniter starts working and performs a self-test simultaneously. The judgment condition is "the current is greater than A1 and lasts for n1 seconds". Step 2-2: Start the motor to rotate the turbine, with a target speed of R1; Steps 2-3: When the turbine speed exceeds 1000 RPM and the electric ignition head operates for more than n2 seconds, open the solenoid valve of the ignition fuel circuit; start the fuel pump, and maintain the fuel pump voltage at V1. Steps 2-4: If the exhaust temperature rises above T1℃ or the current exhaust temperature is greater than T2℃ and fuel supply begins for n2 seconds, then ignition is considered successful and the preheating stage begins.

[0007] Preferably, step 3 specifically comprises: Step 3-1: After entering the preheating stage, the target speed of the starter motor is increased to R2 to further increase the intake air volume; the value of R2 is greater than R1. Step 3-2: When the exhaust temperature is greater than T2℃, the oil pump voltage drops from V1 to V2, the main oil circuit solenoid valve opens, the initial frequency is 2Hz, and it increases by 1Hz per second, with each opening time being n3 milliseconds; the oil pump voltage drops by ΔV per second, and the lower limit of the oil pump voltage is V3. Step 3-3: The preheating stage is completed when "the exhaust temperature is greater than T3℃ and the solenoid valve opening and closing frequency is greater than n4Hz" or "the exhaust temperature is greater than T4℃ and the current temperature change rate is positive".

[0008] Preferably, step 4 specifically comprises: Once the acceleration phase begins, the main fuel circuit solenoid valve opens, and the ignition fuel circuit solenoid valve closes, meaning the fuel required for combustion is entirely supplied by the main fuel circuit. Taking into account factors such as air pressure, exhaust temperature, engine speed, rate of temperature change, and rate of speed change, the fuel flow calculation formula for the acceleration phase is as follows: (1) in: , , Steady-state operating condition coefficient; : Rotational speed change correction coefficient; Temperature change correction factor; Fuel supply rate (g / min); Engine speed; : Rate of change of rotational speed; Exhaust temperature; : Rate of temperature change; Intake air pressure; :time; , , Critical speeds at different stages; Exhaust temperature correction function The calculation formula is as follows: (2) Reference exhaust temperature; , , This is a correction factor; Step 4-1: Enter the acceleration process, turn off the electric ignition head, close the ignition fuel circuit solenoid valve, and set the engine target speed to R3; the fuel required for combustion of the turbojet engine is entirely supplied by the main fuel circuit, and the fuel flow rate remains constant; Step 4-2: After the engine speed reaches R3, the starter motor power remains unchanged, and the fuel supply quantity m1 is dynamically calculated according to the fuel flow calculation formula during the acceleration phase. Step 4-3: After the engine speed reaches R4, the starter motor is turned off, and the fuel supply quantity m2 is dynamically calculated according to the fuel flow calculation formula during the acceleration phase. Step 4-4: After the engine speed reaches R5, the fuel supply m3 is dynamically calculated according to the fuel flow calculation formula during the acceleration phase, and is maintained until idle speed.

[0009] Preferably, step 5 specifically comprises: When the engine speed is lower than the minimum speed, it is determined that the engine has stalled, and the process returns to step 2.

[0010] Preferably, step 6 specifically comprises: At room temperature, the fuel flow rate is tested according to the fuel pump voltages V2 and V3, and recorded as follows: , The fuel pump voltage was calibrated at different exhaust temperatures, and the fuel flow rate was tested. , The corresponding voltage; Based on the current exhaust temperature T, the fuel flow rate at the current exhaust temperature is calculated using interpolation. and The corresponding voltages , ;according to , And the oil pump voltage before correction V Calculate the corrected oil pump voltage The calculation formula is as follows: (3).

[0011] Preferably, n1 is 0.2 to 1, n2 is 3 to 5, n3 is 40, and n4 is 6.

[0012] Preferably, the value of R1 is between 2000 and 5000 RPM; the value of T1 is between 5 and 20°C.

[0013] Preferably, the value of K ranges from 0.015 to 0.035, the value of A ranges from 0.008 to 0.020, and the value of B ranges from -0.2 to +0.05. The value range is 0.8 to 1.2. The value range is 0.4 to 0.8. The value range is -0.10 to 0.02.

[0014] Preferably, the minimum speed is 70%-80% of the engine idle speed.

[0015] The beneficial effects of this invention are as follows: The outstanding advantages of this invention are low cost, convenient implementation, and the ability to achieve rapid electric start-up of micro turbojet engines at high altitudes. It has high reference value and potential for promotion in related fields. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the oil circuit of the turbojet engine of the present invention; Figure 2 This is a schematic diagram of the turbojet engine fuel control strategy of the present invention; Figure 3 This is a schematic diagram of the turbojet engine speed control strategy of the present invention; Figure 4 This is a flowchart of the ignition stage of the turbojet engine of the present invention; Figure 5 This is a flowchart of the preheating stage of the turbojet engine in this invention; Figure 6 This is a flowchart of the acceleration phase of the turbojet engine of the present invention; Figure 7 This is a flowchart of the operation phases of the turbojet engine of the present invention. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] This invention divides the turbojet engine starting process into four stages: ignition, preheating, acceleration, and operation. It provides the threshold conditions for each stage transition, as well as the speed control and fuel control strategies for each stage. To address the issue of turbojet engines easily stalling during acceleration, this invention proposes a dynamic fuel control calculation method for acceleration. To address fuel flow rate changes caused by temperature, this invention proposes a fuel pump voltage and temperature compensation correction method. Through these measures, rapid and reliable starting of the turbojet engine is achieved at altitudes below 5000m.

[0019] This invention relates to a turbojet engine fuel pump that simultaneously supplies fuel to both the main fuel circuit and the ignition fuel circuit. The ignition fuel circuit and the main fuel circuit are each controlled by a solenoid valve. The ignition fuel circuit leads to the ignition nozzle, and the main fuel circuit leads to the combustion chamber evaporator. The turbojet engine is equipped with temperature and speed sensors to collect real-time data on the engine's exhaust temperature and speed.

[0020] 1. Ignition stage; The main purpose of the ignition stage is to achieve stable and reliable combustion of atomized fuel.

[0021] Step 1.1: After entering the ignition process, the electric igniter starts working and simultaneously performs a self-test. The judgment condition is "the current is greater than A1 and lasts for n1 seconds". The value of A1 can be determined according to the igniter power, and n1 is usually 0.2~1s; Step 1.2: Start the starter motor to rotate the turbine, with a target speed of R1; R1 can be selected from 2000-5000 RPM. The main purpose is to maintain a certain amount of air intake to provide the oxygen required for atomized fuel combustion, while avoiding excessive speed, which would disperse the atomized fuel and cause ignition difficulties.

[0022] Step 1.3: When the turbine speed exceeds 1000 RPM and the electric ignition head operates for more than n2s, open the ignition fuel circuit solenoid valve. Start the fuel pump, and maintain the fuel pump voltage at V1; Due to the low temperature environment at high altitudes, igniting fuel is more difficult than on the ground. The electric ignition head needs to be fully heated to achieve a higher temperature than when starting on the ground. Therefore, the electric ignition head's operating time (n2s) should be 3-5 seconds. The fuel pump voltage (V1) should be sufficient to fully atomize the fuel, corresponding to a fuel pressure of 1-3 MPa.

[0023] Step 1.4: If the exhaust temperature rises above T1℃ or the current exhaust temperature is greater than T2℃ and fuel supply has started for n2 seconds, ignition is considered successful and the preheating stage begins. After the atomized fuel is successfully ignited, the heat generated by the combustion of the fuel will cause the exhaust temperature of the combustion chamber to rise. Therefore, the value of T1 should be greater than the fluctuation of the temperature sensor value, which is usually 5-20℃.

[0024] When the engine unexpectedly stalls and restarts, the combustion chamber temperature is still relatively high. At this time, it is necessary to use this residual temperature to quickly complete the restart. The heat generated by the combustion of atomized fuel cannot raise the exhaust temperature of the combustion chamber. The ignition success judgment condition is changed to "current exhaust temperature > T2℃ and n2 seconds after fuel supply starts".

[0025] 2. Preheating stage; The main purpose of the preheating stage is to increase the exhaust temperature of the combustion chamber, create conditions for the vaporization of fuel in the evaporator tube, and realize the switch from fuel supply through the ignition circuit to fuel supply through the main circuit.

[0026] Step 2.1: After entering the preheating stage, increase the target speed of the starter motor to R2 to further increase the intake air volume. The value of R2 should be slightly greater than R1.

[0027] Step 2.2: When the exhaust temperature is greater than T2℃, the oil pump voltage drops from V1 to V2, the main oil circuit solenoid valve opens, with an initial frequency of 2Hz, increasing by 1Hz per second, and an opening time of n3 milliseconds. The oil pump voltage drops by ΔV per second, and the lower limit of the oil pump voltage is V3.

[0028] The main fuel circuit solenoid valve operates in a normally closed mode. When the solenoid valve opens, fuel enters the main fuel circuit. Simultaneously, due to the pressure distribution effect in the main fuel circuit, the pressure in the ignition fuel circuit decreases, leading to poor fuel atomization or even complete atomization. By gradually increasing the opening and closing frequency of the main fuel circuit solenoid valve, the fuel quantity in the ignition fuel circuit gradually decreases, while the fuel quantity in the main fuel circuit gradually increases, achieving a transition from fuel supply in the ignition fuel circuit to fuel supply in the main fuel circuit.

[0029] Step 2.3: The preheating stage is completed when the exhaust temperature is greater than T3℃ and the solenoid valve opening and closing frequency is greater than n4Hz or the exhaust temperature is greater than T4℃ and the current temperature change rate is positive.

[0030] The preheating phase is considered complete when the combustion chamber exhaust temperature meets the requirements and the solenoid valve opening and closing frequency meets the requirements. When the engine is restarted after being shut down, the combustion chamber has a high residual temperature, and the fuel in the main fuel circuit can be atomized by the evaporator. To make full use of the residual temperature in the combustion chamber, the solenoid valve frequency judgment step can be skipped and replaced with a judgment based on whether the exhaust temperature is greater than T4℃ and the current temperature change rate is positive.

[0031] 3. Acceleration phase; The main purpose of the acceleration phase is to rapidly increase the turbojet engine speed by gradually increasing the fuel supply. Once in the acceleration phase, the main fuel circuit solenoid valve is fully open, and the ignition fuel circuit solenoid valve is closed, with the fuel required for combustion supplied entirely by the main fuel circuit. The conventional acceleration phase fuel supply strategy is a fixed-ratio acceleration, with the fuel flow increasing slowly according to a certain proportion. This strategy has a long start-up time and is prone to stalling at high altitudes. To quickly increase the turbojet engine speed while avoiding stalling due to fuel-air mismatch caused by excessive fuel, this invention proposes a fuel flow calculation method for the acceleration phase, comprehensively considering factors such as air pressure, exhaust temperature, engine speed, temperature change rate, and engine speed change rate. The specific calculation method is as follows: (1) Exhaust temperature correction function The calculation formula is as follows: (2) The specific steps for starting a turbojet engine during the acceleration phase are as follows: Step 3.1: Enter the acceleration process, turn off the electric ignition head and the ignition solenoid valve, and increase the engine target speed to R3. During this stage, the fuel required for combustion of the turbojet engine is supplied entirely by the main fuel circuit. The fuel flow rate remains constant.

[0032] Step 3.2: After the engine speed reaches R3, the starter motor power is maintained, and the fuel supply quantity m1 is dynamically calculated according to the fuel flow calculation formula during the acceleration phase.

[0033] Step 3.3: After the engine speed reaches R4, the starter motor is turned off, and the fuel supply quantity m2 is dynamically calculated according to the fuel flow calculation formula during the acceleration phase.

[0034] Step 3.4: After the engine speed reaches R5, the fuel supply m3 is dynamically calculated according to the fuel flow calculation formula during the acceleration phase, and is maintained until idle speed.

[0035] During acceleration, the fuel pump voltage V is calculated in real time based on the corresponding fuel flow rate.

[0036] 4. Operation phase; When the engine speed is lower than the minimum speed, it is determined that the engine has stalled and will re-enter the ignition stage.

[0037] The minimum speed can usually be set at 70%-80% of the engine idle speed.

[0038] 5. Fuel flow temperature compensation correction method; Rapid starting at high altitudes is extremely sensitive to fuel flow. Aviation kerosene exhibits significant viscosity variations at different temperatures, resulting in substantial differences in fuel flow rate at the same pump voltage. Controlling fuel flow based solely on pump voltage can easily lead to either rich-fuel or lean-fuel engine shutdown. To eliminate the influence of temperature on fuel flow rate, this invention proposes a pump voltage temperature compensation correction method.

[0039] At room temperature, the fuel flow rate is tested according to the fuel pump voltages V2 and V3, and recorded as follows: , The fuel pump voltage was calibrated at different temperatures, and the fuel flow rate was tested. , The corresponding voltages are shown in Table 1: Table 1

[0040] Based on the current exhaust temperature T, the fuel flow rate at the current exhaust temperature can be calculated by interpolation. and The corresponding voltages , .according to , And the oil pump voltage before correction V The corrected oil pump voltage can be calculated. The calculation formula is as follows: (3) Example: The starting method for a turbojet engine is as follows: Step 1: After entering the ignition process, the electric igniter starts working and performs a self-test simultaneously. The judgment condition is "current greater than 300mA for 0.5 seconds". Step 2: Start the starter motor to drive the turbine, with a target speed of 3000 RPM; Step 3: When the turbocharger speed exceeds 1000 RPM and the electric ignition head operates for more than 5 seconds, open the ignition fuel circuit solenoid valve. Start the fuel pump, maintaining the fuel pump voltage at 3.1V; Step 4: "When the exhaust temperature rises above 10°C", ignition is considered successful, and the preheating stage begins; Step 5: After entering the preheating stage, the target speed of the starter motor is increased to 5000 RPM, and the oil pump voltage remains unchanged at 3.1V; Step 6: When the exhaust temperature exceeds 150℃, the oil pump voltage drops from 3.1V to 1.5V, the main oil circuit solenoid valve opens, with an initial frequency of 2Hz, increasing by 1Hz per second, and each opening time being 40 milliseconds. The oil pump voltage drops by 0.2V per second, and the lower limit of the oil pump voltage is 0.7V. Step 7: When the exhaust temperature is greater than 200℃ and the solenoid valve opening and closing frequency is greater than 6Hz, the preheating stage is completed and the acceleration stage begins. Step 8: Enter the acceleration phase, turn off the electric spark plug, increase the engine target speed to 17000 RPM, and keep the fuel pump voltage at 1.5V. Step 9: After the engine speed reaches 17000 RPM, the starter motor power is maintained, and the fuel supply quantity m1 is calculated in real time according to the fuel flow calculation formula during the acceleration phase. 0.025 For 800, 0.9 It is 0.6. It is -0.08; Step 10: After the engine speed reaches 32000 RPM, the starter motor is turned off. The fuel supply quantity m2 is calculated in real time according to the fuel flow calculation formula during acceleration. The value is 0.015, while other correction factors remain unchanged; Step 11: After the engine speed reaches 42000 RPM, the fuel supply quantity (m3) is calculated in real time according to the fuel flow calculation formula during acceleration, and maintained until idle speed. The value is 0.035, while other correction factors remain unchanged.

[0041] See fuel supply strategy during engine starting process Figure 2 The curves in the graph represent the fuel pump voltage, fuel pressure, and solenoid valve parameters, respectively. When the solenoid valve is normally closed, the corresponding status signal is 0; when it is open, the status signal is 1.

[0042] See engine starting speed strategy Figure 3 For the ignition phase procedure, see [link to procedure]. Figure 4 Where Temp is the current exhaust temperature and T is the current time. See the preheating process below. Figure 5 See the accelerated phase process. Figure 6 For the operational phase process, see [link / document name] Figure 7 .

[0043] An example of fuel flow temperature compensation is as follows: Under normal temperature conditions, V2 is 0.7V, corresponding to a flow rate of 50g / min, and V3 is 1.4V, corresponding to a flow rate of 105g / min. The oil pump voltages corresponding to these flow rates are shown in Table 2.

[0044] Table 2

[0045] Assuming the current exhaust temperature is 10℃, , The oil pump voltage V and The conversion formula is as follows: 。

Claims

1. A method for rapid electric starting of a micro turbojet engine at high altitude, characterized in that, Includes the following steps: Step 1: The fuel pump of the turbojet engine supplies fuel to both the main fuel line and the ignition fuel line simultaneously. The main fuel line and the ignition fuel line are each controlled by a solenoid valve to open and close the fuel lines. The ignition fuel line leads to the electric ignition head, and the main fuel line leads to the combustion chamber evaporator. The turbojet engine is equipped with a temperature sensor and a speed sensor to collect the exhaust temperature and speed of the turbojet engine in real time. Step 2: Ignition stage; Step 3: Preheating stage; Step 4: Acceleration Phase; Step 5: Execution phase; Step 6: Fuel flow temperature compensation correction.

2. The method for high-altitude rapid electric starting of a micro turbojet engine according to claim 1, characterized in that, Step 2 specifically involves: Step 2-1: After entering the ignition process, the electric igniter starts working and performs a self-test simultaneously. The judgment condition is "the current is greater than A1 and lasts for n1 seconds". Step 2-2: Start the motor to rotate the turbine, with a target speed of R1; Steps 2-3: When the turbine speed exceeds 1000 RPM and the electric ignition head operates for more than n2 seconds, open the solenoid valve of the ignition fuel circuit; start the fuel pump, and maintain the fuel pump voltage at V1. Steps 2-4: If the conditions are met that "exhaust temperature rises above T1℃" or "current exhaust temperature > T2℃ and fuel supply begins for n2 seconds", then ignition is considered successful and the preheating stage begins.

3. The method for rapid high-altitude electric starting of a micro turbojet engine according to claim 2, characterized in that, Step 3 specifically involves: Step 3-1: After entering the preheating stage, the target speed of the starter motor is increased to R2 to further increase the intake air volume; the value of R2 is greater than R1. Step 3-2: When the exhaust temperature is greater than T2℃, the oil pump voltage drops from V1 to V2, the main oil circuit solenoid valve opens, the initial frequency is 2Hz, and it increases by 1Hz per second, with each opening time being n3 milliseconds; the oil pump voltage drops by ΔV per second, and the lower limit of the oil pump voltage is V3. Step 3-3: The preheating stage is completed when "the exhaust temperature is greater than T3℃ and the solenoid valve opening and closing frequency is greater than n4Hz" or "the exhaust temperature is greater than T4℃ and the current temperature change rate is positive".

4. The method for rapid high-altitude electric starting of a micro turbojet engine according to claim 3, characterized in that, Step 4 specifically involves: Once the acceleration phase begins, the main fuel circuit solenoid valve opens, and the ignition fuel circuit solenoid valve closes, meaning the fuel required for combustion is entirely supplied by the main fuel circuit. Taking into account factors such as air pressure, exhaust temperature, engine speed, rate of temperature change, and rate of speed change, the fuel flow calculation formula for the acceleration phase is as follows: （1） in: , , Steady-state operating condition coefficient; : Rotational speed change correction coefficient; Temperature change correction factor; Fuel supply rate (g / min); Engine speed; : Rate of change of rotational speed; Exhaust temperature; : Rate of temperature change; Intake air pressure; :time; , , Critical speeds at different stages; Exhaust temperature correction function The calculation formula is as follows: （2） Reference exhaust temperature; , , This is a correction factor; Step 4-1: Enter the acceleration process, turn off the electric ignition head, close the ignition fuel circuit solenoid valve, and set the engine target speed to R3; the fuel required for combustion of the turbojet engine is entirely supplied by the main fuel circuit, and the fuel flow rate remains constant; Step 4-2: After the engine speed reaches R3, the starter motor power remains unchanged, and the fuel supply quantity m1 is dynamically calculated according to the fuel flow calculation formula during the acceleration phase. Step 4-3: After the engine speed reaches R4, the starter motor is turned off, and the fuel supply quantity m2 is dynamically calculated according to the fuel flow calculation formula during the acceleration phase. Step 4-4: After the engine speed reaches R5, the fuel supply m3 is dynamically calculated according to the fuel flow calculation formula during the acceleration phase, and is maintained until idle speed.

5. A method for rapid electric starting of a micro turbojet engine at high altitude according to claim 4, characterized in that, Step 5 specifically involves: When the engine speed is lower than the minimum speed, it is determined that the engine has stalled, and the process returns to step 2.

6. The method for high-altitude rapid electric starting of a micro turbojet engine according to claim 5, characterized in that, Step 6 specifically involves: At room temperature, the fuel flow rate is tested according to the fuel pump voltages V2 and V3, and recorded as follows: , The fuel pump voltage was calibrated at different exhaust temperatures, and the fuel flow rate was tested. , The corresponding voltage; Based on the current exhaust temperature T, the fuel flow rate at the current exhaust temperature is calculated using interpolation. and The corresponding voltages , ;according to , And the oil pump voltage before correction V Calculate the corrected oil pump voltage The calculation formula is as follows: （3）。 7. A method for rapid high-altitude electric starting of a micro turbojet engine according to claim 6, characterized in that, The value of n1 is 0.2 to 1, the value of n2 is 3 to 5, the value of n3 is 40, and the value of n4 is 6.

8. A method for rapid electric starting of a micro turbojet engine at high altitude according to claim 7, characterized in that, The value of R1 is between 2000 and 5000 RPM; the value of T1 is between 5 and 20℃.

9. A method for rapid electric starting of a micro turbojet engine at high altitude according to claim 8, characterized in that, The value of K ranges from 0.015 to 0.035, the value of A ranges from 0.008 to 0.020, and the value of B ranges from -0.2 to +0.

05. The value range is 0.8 to 1.

2. The value range is 0.4 to 0.

8. The value range is -0.10 to 0.

02.

10. A method for rapid electric starting of a micro turbojet engine at high altitude according to claim 9, characterized in that, The minimum speed is 70%-80% of the engine idle speed.

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