Low temperature engine intermittent emission on-line control system and method

Abstract

The application discloses an intermittent discharge online control system of a low-temperature engine, which comprises a control gas bottle, an electric valve and a pre-cooling discharge valve which are sequentially connected through pipelines; the pre-cooling discharge valve is communicated with the electric valve, a liquid oxygen main valve, a rocket liquid oxygen storage tank and a discharge pipeline through pipelines; the system further comprises a rocket-borne computer and a temperature sensor which is installed on a low-temperature pipeline connected with the engine; the temperature sensor is connected with the rocket-borne computer through a measuring cable; and the electric valve is connected with the rocket-borne computer through a control cable. The application further discloses an intermittent discharge online control method of a low-temperature engine. The method improves the adaptability of the existing discharge control method to different flight tasks, reduces the propellant discharge consumption and improves the success rate and economy of the rocket flight task by monitoring and dynamically optimizing the intermittent discharge timing in real time.

Description

Technical Field

[0001] This invention belongs to the field of liquid rocket engine technology, specifically relating to an online control system for intermittent emissions from cryogenic engines, and also to a method for online control of intermittent emissions from cryogenic engines. Background Technology

[0002] In the modern aerospace field, cryogenic liquid rocket engines have become the core power unit of launch vehicles due to their advantages such as high specific impulse and high performance.

[0003] With the development of liquid rocket technology, in order to achieve goals such as improving rocket carrying capacity and enabling stage recovery and reuse, engines are required to have multiple restart capabilities.

[0004] After the previous shutdown, the engine does not generate power, and the rocket body is in a powerless gliding working phase. During this phase, preparations need to be made for the next engine ignition.

[0005] For cryogenic liquid rocket engines, a series of stringent starting conditions must be met before ignition, with propellant temperature being one of the key indicators. Especially for cryogenic liquid rocket engines capable of multiple starts, during the unpowered coasting phase between two starts, it is necessary to intermittently release the propellant from the engine cavity through engine valves.

[0006] Active heat exchange is achieved through the flow of propellant, thereby ensuring that the engine, delivery pipelines, pumps and other components are fully pre-cooled, preventing the vaporization of low-temperature propellant during the start-up process and avoiding engine start-up failure due to air entrainment.

[0007] Currently, before rocket launch, the intermittent emission sequence of the engine is injected into the onboard computer. During the coasting phase before engine restart, the onboard computer directly controls the cryogenic propellant pre-cooling emission valve to implement intermittent engine emissions. The intermittent emission sequence is obtained through engine ground tests, and the pre-cooling emission valve closes and opens at fixed intervals. This method has several drawbacks:

[0008] There are significant differences between engine ground tests and actual rocket flights. The emission systems on ground test benches differ from those in actual flight, making the intermittent emission effects obtained from ground tests inaccurately reflect the realities of rocket flight. Therefore, fixed intermittent emission procedures developed based on ground tests are unlikely to achieve optimal control in actual flights, often carrying the risk of start-up failure due to insufficient precooling or waste of cryogenic propellant due to excessive precooling.

[0009] The engine emission system is closely coupled with the rocket propulsion system, and the same engine emission program may produce different emission effects on different rockets. For example, a certain fixed emission program can meet the engine precooling requirements on rocket A, but it cannot achieve the expected effect on rocket B, resulting in abnormal engine start-up.

[0010] For the same rocket, the total time of intermittent engine emissions is closely related to the total duration of the unpowered coasting phase during rocket flight. Because rockets undertake diverse payload launch missions, with varying payload weights and target trajectories, the total coasting time differs.

[0011] Furthermore, before the rocket engine restarts, the propellant temperature is affected by a variety of factors, such as propellant loading temperature, engine operating time, and the effectiveness of thermal insulation. The complexity of these factors makes it extremely difficult to accurately predict the propellant temperature changes during the glide phase before flight, thus hindering the development of a reasonable and effective discharge procedure.

[0012] Traditional intermittent emission control methods with fixed timing are difficult to adapt to different rocket models and flight missions, potentially leading to insufficient engine precooling, abnormal engine start-up, and even engine start-up failure in severe cases. A new emission control system and method for cryogenic liquid rocket engines is urgently needed to solve this technical challenge. Summary of the Invention

[0013] The first objective of this invention is to provide an online control system for intermittent emissions from cryogenic engines. By real-time monitoring and dynamic optimization of the intermittent emission timing, this system improves the adaptability of existing emission control methods to different flight missions, reduces propellant emission consumption, and enhances the success rate and economy of rocket flight missions.

[0014] The second objective of this invention is to provide an online control method for intermittent emissions from cryogenic engines. By real-time monitoring and dynamic optimization of the intermittent emission timing, this method improves the adaptability of existing emission control methods to different flight missions, reduces propellant emission consumption, and enhances the success rate and economy of rocket flight missions.

[0015] The first technical solution adopted in this invention is an online control system for intermittent emissions from a cryogenic engine, comprising a control gas cylinder, an electric gas valve, and a pre-cooling emission valve connected sequentially via pipelines; the pre-cooling emission valve is connected to the electric gas valve, the liquid oxygen main valve, the rocket liquid oxygen storage tank, and the emission pipeline via pipelines.

[0016] It also includes an onboard computer and a temperature sensor, with the temperature sensor installed on a cryogenic pipeline connected to the engine; the temperature sensor is connected to the onboard computer via a measuring cable; and an electric air valve is connected to the onboard computer via a control cable.

[0017] The invention is further characterized in that:

[0018] The precooling discharge valve is a two-position three-way valve, equipped with a control port, a cryogenic propellant inlet, a return port, and a discharge port. The control port of the precooling discharge valve is connected to an electric gas valve via a pipeline, the cryogenic propellant inlet is connected to the liquid oxygen main valve via a pipeline, the return port is connected to the rocket's liquid oxygen storage tank via a pipeline, and the discharge port is directly connected to the atmosphere via a discharge pipeline.

[0019] The electric pneumatic valve is a pilot-operated diaphragm solenoid valve.

[0020] The electric valve is powered by electric current, which is supplied by the onboard computer via a control cable, providing a low-voltage DC power of 27V.

[0021] The second technical solution adopted in this invention is a method for online control of intermittent emissions from cryogenic engines, which employs the aforementioned online control system for intermittent emissions from cryogenic engines, specifically as follows:

[0022] Step 1: Before the cryogenic engine intermittent emission online control system is put into operation, the configuration parameters are injected into the onboard computer;

[0023] Step 2: Start the online control system for intermittent emissions from the low-temperature engine;

[0024] Step 3: The onboard computer executes emission control according to the online emission control strategy.

[0025] The invention is further characterized in that:

[0026] In step 1, the injection of configuration parameters is performed during the ground preparation phase before rocket launch. These configuration parameters include: the total duration t of the rocket's unpowered coasting phase. h Target temperature range [T1, T2], kb calibration coefficient of temperature sensor.

[0027] In step 2, the low-temperature engine intermittent emission online control system is initially in a stopped emission state, and the pre-cooled emission valve is in a closed state.

[0028] Once the onboard computer sends the engine shutdown command, it immediately enters the emission control phase, and the low-temperature engine intermittent emission online control system is activated.

[0029] In step 3, the specific online emission control strategy is as follows:

[0030] 1) If the gliding time t h If the time is less than 20 seconds, formulate the following strategy:

[0031] a) The onboard computer sends a command to open the pre-cooling discharge valve, thus opening the valve for continuous discharge; b) Interval t hThen, the onboard computer sends a command to close the pre-cooling emission valve, stopping emissions, and the engine restarts.

[0032] 2) If the gliding time t h If the time is ≥20 seconds, then t h Divided into two phases, the following strategy was formulated:

[0033] a) The duration of the first phase is: t h -20 seconds, the second phase lasts for 20 seconds;

[0034] b) In the first phase, a measurement and control cycle is defined as 300 milliseconds;

[0035] c) The first 200 milliseconds of each measurement and control cycle are used for measurement. Temperature values ​​are collected through a temperature sensor. Specifically, within the first 200 milliseconds of each measurement and control cycle, a temperature value is collected every 20 milliseconds, i.e., the sampling frequency is 50Hz. The average of 10 measured temperatures is calculated to obtain T. ave ;

[0036] d) The average temperature T obtained in step c) ave Compared with the target temperature range [T1, T2], if T ave If T2 is greater than or equal to T2, then send a command to open the precooling discharge valve until T2 is reached. ave When T1 is less than or equal to 1, send a command to close the precooling discharge valve;

[0037] e) The last 100 milliseconds of each measurement and control cycle are used for the operation of the electric gas valve and the pre-cooling discharge valve actuators; according to the instructions in step d), in the last 100 milliseconds of each measurement and control cycle, the onboard computer controls the electric gas valve to be energized or de-energized, so that the pre-cooling discharge valve is opened or closed, thereby starting or stopping the discharge of cryogenic propellant.

[0038] f) In the first stage, steps b) to e) are executed repeatedly in a 300-millisecond monitoring and control cycle until the remaining coasting time t is reached. h剩余 <20 seconds;

[0039] g) In the second stage, i.e. when the remaining taxiing time t h剩余 If the time is less than 20 seconds, send the command to open the pre-cooling discharge valve (7) again to perform continuous discharge;

[0040] h) After continuous emission is completed, the onboard computer sends a command to close the pre-cooling emission valve, stopping the emission, and the engine restarts.

[0041] The beneficial effects of this invention are:

[0042] (1) Improve rocket adaptability: The method and system of this invention break free from the limitations of traditional fixed emission procedures and can adjust the intermittent emission sequence in real time according to the characteristics of different rockets and the requirements of flight missions. Whether it is a rocket of different models or the same rocket performing different missions, this method can achieve precise propellant temperature control, which greatly improves the adaptability of rockets to various missions.

[0043] (2) Improved flight mission adaptability: The method of the present invention measures the temperature of the monitored part in real time and compares it with the target temperature. Based on the control strategy, it dynamically adjusts the intermittent propellant discharge program and controls the opening and closing of the pre-cooling discharge valve. This real-time adjustment method enables the system to adapt to changes in factors such as the duration of the unpowered taxiing phase and the initial temperature of the propellant in different flight missions, ensuring that the engine can meet the restart conditions under various complex flight missions.

[0044] (3) Reduced propellant consumption: During rocket flight, the method of this invention precisely implements an intermittent emission procedure based on real-time measured temperature parameters and preset engine start-up conditions. This avoids the propellant waste caused by excessive precooling in traditional methods, significantly reduces propellant consumption while ensuring reliable engine start-up, improves propellant utilization efficiency, and increases rocket payload capacity.

[0045] (4) High versatility: The system and method of this invention are not limited by the cycle mode or thrust level of liquid rocket engines. They are applicable to various pump-pressed liquid rocket engines using cryogenic propellants, including electric pump cycle, gas generator cycle, and staged combustion cycle. They have strong versatility and practicality. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the structure of the online control system for intermittent emissions from a cryogenic engine according to the present invention;

[0047] Figure 2 This is a flowchart of the online control method for intermittent emissions in a cryogenic engine according to the present invention;

[0048] Figure 3 This is a graph showing the liquid oxygen inlet temperature of Example 1;

[0049] Figure 4 This is a state curve diagram of the precooling discharge valve in Example 1;

[0050] Figure 5 This is a control cylinder pressure curve diagram for Example 1.

[0051] In the diagram, 1. Onboard computer, 2. Measurement cable, 3. Control cable, 4. Temperature sensor, 5. Liquid oxygen pump, 6. Liquid oxygen main valve, 7. Pre-cooling discharge valve, 8. Electric gas valve, 9. Control gas cylinder, 10. Cryogenic pipeline, 11. Rocket liquid oxygen storage tank, 12. Discharge pipeline, 13. Engine combustion assembly, 14. Liquid oxygen;

[0052] 7-1. Control port, 7-2. Cryogenic propellant inlet, 7-3. Return port, 7-4. Discharge port. Detailed Implementation

[0053] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0054] This invention provides an online control system for intermittent emissions from cryogenic engines, such as... Figure 1 As shown, it includes a control gas cylinder 9, an electric gas valve 8 and a pre-cooling discharge valve 7 connected in sequence through pipelines; the pre-cooling discharge valve 7 is connected to the electric gas valve 8, the liquid oxygen main valve 6, the rocket liquid oxygen storage tank 11 and the discharge pipeline 12 through pipelines respectively.

[0055] It also includes an onboard computer 1 and a temperature sensor 4. The temperature sensor 4 is installed on a cryogenic pipeline 10 connected to the engine. The temperature sensor 4 is connected to the onboard computer 1 via a measuring cable 2. The electric air valve 8 is connected to the onboard computer 1 via a control cable 3.

[0056] The precooling discharge valve 7 is a two-position three-way valve. The precooling discharge valve 7 is equipped with a control port 7-1, a cryogenic propellant inlet 7-2, a return port 7-3, and a discharge port 7-4. The control port 7-1 of the precooling discharge valve 7 is connected to the electric air valve 8 through a pipeline, the cryogenic propellant inlet 7-2 is connected to the liquid oxygen main valve 6 through a pipeline, the return port 7-3 is connected to the rocket liquid oxygen storage tank through a pipeline, and the discharge port 7-4 is directly connected to the atmosphere through a discharge pipeline.

[0057] in:

[0058] Onboard Computer 1: The onboard computer stores an intermittent emission online control strategy. This control strategy is written into the onboard computer in the form of control software. By analyzing and processing temperature data, the engine emission process is controlled online in real time according to the preset target temperature.

[0059] Cables: including measuring cable 2 and control cable 3.

[0060] The measuring cable 2 is used to connect the onboard computer 1 and the temperature sensor 4 for transmitting temperature data;

[0061] The control cable 3 is used to connect the onboard computer 1 and the electric valve 8, and is used to transmit the control signals sent by the onboard computer 1 to control the opening and closing of the electric valve 8.

[0062] Temperature sensor 4: An insertion-type temperature sensor is used, and temperature sensor 4 is installed on the low-temperature pipeline.

[0063] The number of temperature sensors 4 is configured according to the type and quantity of cryogenic propellant on the engine and the number of temperature parameters to be measured. They can collect the temperature data of the cryogenic propellant in real time and accurately, and transmit the data to the onboard computer 1, providing key information for the system's control decisions.

[0064] Pre-cooling discharge valve 7: Pre-cooling discharge valve 7 is a pneumatically controlled valve, serving as an on / off actuator. It is a two-position, three-way valve with a control port 7-1 for supplying high-pressure control gas, a cryogenic propellant inlet 7-2 connected to the engine, and a return port 7-3 and a discharge port 7-4 as outlets. The return port 7-3 is connected to the rocket's liquid oxygen storage tank 11, and the discharge port 7-4 is connected to the discharge pipeline 12, directly venting to the atmosphere. Pre-cooling discharge valve 7 controls the switching of its position by supplying or removing gas into the control chamber through its control port, thus switching between the return port 7-3 and the discharge port 7-4. The energy source for the operation of pre-cooling discharge valve 7 is high-pressure gas, typically helium or nitrogen. When the precooling discharge valve 7 is not ventilated, the cryogenic propellant inlet 7-2 of the precooling discharge valve 7 is connected to the return port 7-3, and the discharge port 7-4 is closed; when the precooling discharge valve 7 is ventilated, the cryogenic propellant inlet 7-2 is connected to the discharge port 7-4, and the return port 7-3 is closed. High-pressure gas is stored in the control gas cylinder 9.

[0065] Electric air valve 8: Electric air valve 8 is a pilot-operated diaphragm solenoid valve, which is a switching actuator. It opens when energized and closes when de-energized, controlling the flow of high-pressure gas. Its operating energy is current, which is provided by the onboard computer 1 through the control cable 3, providing low-voltage DC power with a rated voltage of 27V.

[0066] Control gas cylinder 9: Provides control gas to the pre-cooling discharge valve 7, ensuring its proper operation and supporting emission control. Control gas cylinder 9 is filled with high-pressure control gas, typically helium or nitrogen.

[0067] Under the control of the onboard computer 1, the electric gas valve 8 drives the pre-cooling discharge valve 7 to open and close by controlling the gas pressure, thereby achieving precise control of the propellant discharge process.

[0068] The electric air valve 8 and the pre-cooling discharge valve 7 are the actuators in this system. The onboard computer 1 controls the flow of gas from the control cylinder 9 by energizing or de-energizing the electric air valve 8, thereby controlling the opening or closing of the pre-cooling discharge valve 7 and initiating or stopping the pre-cooling discharge process. The specific process is as follows:

[0069] The discharge process: The onboard computer 1 supplies power to the electric gas valve 8 via the control cable 3. The electric gas valve 8 opens, allowing the high-pressure gas in the control gas cylinder 9 to enter the pre-cooling discharge valve 7. The pre-cooling discharge valve 7 then opens, initiating the discharge of cryogenic propellant.

[0070] The process of stopping emissions: the electric gas valve 8 is de-energized and closed, the high-pressure control gas is released, the pre-cooled emission valve 7 is closed, and the emission of cryogenic propellant is stopped.

[0071] Based on the above-mentioned online control system, the present invention also provides an online control method for intermittent emissions from a cryogenic engine, the specific steps of which are as follows:

[0072] Step 1: Inject configuration parameters;

[0073] Configuration parameters are injected into the onboard computer before the cryogenic engine intermittent emission online control system is put into operation.

[0074] The configuration parameters are injected during the ground preparation phase before rocket launch. These parameters include the total duration t of the rocket's unpowered coasting phase. h Target temperature range [T1, T2], kb calibration coefficient of temperature sensor 4.

[0075] The total duration t of the rocket's unpowered gliding phase h The emission control phases are divided according to time.

[0076] The target temperature range [T1, T2] is the temperature range in which the propellant remains liquid under the inlet pressure conditions before engine start-up, in order to avoid vaporization of the cryogenic propellant. It is set according to the engine start-up conditions and temperature requirements under different operating conditions to ensure that the propellant temperature meets the requirements when the engine is restarted.

[0077] The kb calibration coefficient of temperature sensor 4 is used to correct errors that may occur during the measurement process. By calibrating the temperature sensor, the accuracy and reliability of temperature data are improved, providing a precise data basis for subsequent control decisions.

[0078] Step 2: Start the online control system for intermittent emissions from the low-temperature engine;

[0079] The low-temperature engine intermittent emission online control system is initially in a stopped emission state, and the pre-cooled emission valve 7 is in a closed state;

[0080] When the onboard computer 1 sends the engine shutdown command, it immediately enters the emission control phase, and the low-temperature engine intermittent emission online control system is activated.

[0081] Step 3: The onboard computer 1 executes emission control according to the online emission control strategy;

[0082] In step 3, the specific online emission control strategy is as follows, see below. Figure 2 :

[0083] 1) If the gliding time t h If the time is less than 20 seconds, formulate the following strategy:

[0084] a) The onboard computer 1 then sends a command to open the precooling discharge valve 7, which opens the precooling discharge valve 7 for continuous discharge;

[0085] b) Interval t h Then, the onboard computer 1 sends a command to close the pre-cooling emission valve 7, stopping the emission, and the engine restarts.

[0086] Among them, the electric air valve 8, under the control of the onboard computer 1, drives the pre-cooling discharge valve 7 to open and close by controlling the gas pressure;

[0087] 2) If the gliding time t h If the time is ≥20 seconds, then t h Divided into two phases, the following strategy was formulated:

[0088] a) The duration of the first phase is: t h -20 seconds, the second phase lasts for 20 seconds;

[0089] b) In the first phase, a measurement and control cycle is defined as 300 milliseconds;

[0090] c) The first 200 milliseconds of each measurement and control cycle are used for measurement. Temperature values ​​are collected through temperature sensor 4. Specifically, within the first 200 milliseconds of each measurement and control cycle, temperature values ​​are collected every 20 milliseconds, i.e., the sampling frequency is 50Hz. The average of 10 measured temperatures is calculated to obtain T. ave ;

[0091] d) The average temperature T obtained in step c) ave Compared with the target temperature range [T1, T2], if T ave If T2 is greater than or equal to T2, then send a command to open the pre-cooling discharge valve 7 until T2 is reached. ave When T1 is less than or equal to 1, send a command to close the precooling discharge valve 7;

[0092] e) The last 100 milliseconds of each measurement and control cycle are used for the actuators of the electric pneumatic valve 8 and the pre-cooling discharge valve 7. According to the instructions in step d), in the last 100 milliseconds of each measurement and control cycle, the onboard computer 1 controls the electric pneumatic valve 8 to be energized or de-energized, so that the pre-cooling discharge valve 7 is opened or closed, thereby starting or stopping the discharge of cryogenic propellant;

[0093] f) In the first stage, steps b) to e) are executed repeatedly in a 300-millisecond monitoring and control cycle until the remaining coasting time t is reached. h剩余 <20 seconds;

[0094] g) In the second stage, i.e. when the remaining taxiing time t h剩余 If the time is less than 20 seconds, send the command to open the pre-cooling discharge valve 7 again to perform continuous discharge;

[0095] h) After continuous emission is completed, the onboard computer 1 sends a command to close the pre-cooled emission valve 7 to stop emission, and the engine restarts.

[0096] Example 1

[0097] like Figure 1 As shown, taking a liquid oxygen / kerosene engine capable of multiple starts as an example, the specific implementation process of the present invention is explained in detail. According to the rocket's flight profile, the engine starts twice, with an interval of 212 seconds between the first engine shutdown and the second start.

[0098] Hardware components: The engine in this embodiment is a single cryogenic propellant rocket engine, with liquid oxygen as the cryogenic propellant. The cryogenic pipeline 10, liquid oxygen pump 5, and liquid oxygen main valve 6 are components of this engine.

[0099] Cryogenic pipeline 10 enters liquid oxygen pump 5. The outlet of liquid oxygen pump 5 is connected to the inlet of liquid oxygen main valve 6. The outlet of liquid oxygen main valve 6 is connected to engine combustion assembly 13. Liquid oxygen main valve 6 has a pre-cooled discharge port, which is connected to the cryogenic propellant inlet 7-2 of pre-cooled discharge valve 7. The return port 7-3 of pre-cooled discharge valve 7 is connected to the rocket's liquid oxygen storage tank, and the discharge port 7-4 of pre-cooled discharge valve 7 is directly open to the atmosphere.

[0100] High-pressure helium is filled into control gas cylinder 9 as control gas. Control gas cylinder 9 is connected to the inlet of electric gas valve 8, and the outlet of electric gas valve 8 is connected to the control port 7-1 of pre-cooling discharge valve 7.

[0101] Based on the type of propellant and temperature monitoring requirements, a temperature sensor 4 is installed on the engine cryogenic pipeline 10 to monitor the temperature of the engine inlet liquid oxygen 14.

[0102] The onboard computer 1 is connected to the electric air valve 8 via control cable 3, and the temperature sensor 4 is connected to the onboard computer 1 via measurement cable 2, thus completing the system hardware installation.

[0103] The online control method for intermittent emissions from cryogenic engines using the above system is as follows:

[0104] Step 1: Inject Configuration Parameters: During the ground preparation phase before rocket launch, configuration parameters are injected into the onboard computer 1. The total duration t of the rocket's unpowered coasting phase is determined.h For a time of 212 seconds and a target temperature range of [82K, 93.15K] (i.e., T1=82K, T2=93.15K), the kb calibration coefficient is determined with reference to the calibration certificate of temperature sensor 4.

[0105] Step 2: Activate the cryogenic engine intermittent emission online control system: After the onboard computer 1 sends the engine shutdown command, the emission control phase begins, and the cryogenic engine intermittent emission online control system is activated. After the engine shuts down once, the pre-cooling emission valve 7 is initially closed.

[0106] Step 3: The onboard computer 1 executes emission control according to the online emission control strategy;

[0107] Glide time t h =212 seconds, reaching t h For conditions of ≥20 seconds, according to the control strategy, t h Divided into two phases, the following strategy was formulated:

[0108] a) The first phase lasts 192 seconds, and the second phase lasts 20 seconds;

[0109] b) In the first phase, a measurement and control cycle is defined as 300 milliseconds;

[0110] c) The first 200 milliseconds of each measurement and control cycle are used for measurement, during which the temperature sensor collects temperature values. Within the first 200 milliseconds of each measurement and control cycle, the temperature value is measured every 20 milliseconds, i.e., the sampling frequency is 50Hz. The average of the 10 measured temperatures is calculated to obtain T. ave ;

[0111] d) The average temperature T obtained in step c) ave Compared to the target temperature range [82K, 93.15K], if T ave If the temperature is ≥93.15K, a command to open the pre-cooling discharge valve will be sent until T... ave When the temperature is ≤82K, send a command to close the precooling discharge valve;

[0112] e) The last 100 milliseconds of each measurement and control cycle are used for the operation of actuators such as the electric pneumatic valve and the pre-cooling discharge valve. According to the instructions in step d), in the last 100 milliseconds of each measurement and control cycle, the onboard computer energizes or de-energizes the electric pneumatic valve, causing the pre-cooling discharge valve to open or close, thereby starting or stopping the discharge of cryogenic propellant;

[0113] f) In the first stage, steps b) to e) are executed repeatedly in a 300-millisecond monitoring and control cycle until 192 seconds have elapsed.

[0114] In this embodiment, a total of 640 cycles were executed within 192 seconds. The command to open the pre-cooling discharge valve was executed twice.

[0115] The liquid oxygen inlet temperature in this embodiment is shown below. Figure 3 The status of the precooling discharge valve in this embodiment is shown in the figure. Figure 4 Specifically:

[0116] In the first stage, as the heat exchange time increased, the liquid oxygen inlet temperature of the engine gradually increased. During the measurement period of 69.0 seconds to 69.2 seconds, the liquid oxygen inlet temperature T... ave Upon reaching the upper limit of the target temperature range of 93.15K, the pre-cooling discharge valve 7 was opened at 69.3 seconds, allowing liquid oxygen to flow out through the discharge port of the pre-cooling discharge valve 7. Liquid oxygen began to flow inside the liquid oxygen inlet, and the liquid oxygen at the bottom of the rocket's liquid oxygen tank 11 entered the engine, causing the liquid oxygen inlet temperature gauge to continuously decrease. From 84.0 to 84.2 seconds, the liquid oxygen inlet temperature T... ave Once the target temperature range lower limit of 82K is reached, the pre-cooling discharge valve is closed in 84.3 seconds.

[0117] Subsequently, the engine oxidizer inlet temperature gradually increased, and within a measurement period of 175.5 seconds to 175.7 seconds, the liquid oxygen inlet temperature T... ave Once the target temperature range of 93.15K is reached, the pre-cooling discharge valve is opened at 175.8 seconds. Liquid oxygen flows out through the discharge port of the pre-cooling discharge valve, and liquid oxygen begins to flow inside the liquid oxygen inlet. Liquid oxygen at the bottom of the rocket's liquid oxygen tank 11 enters the engine, causing the liquid oxygen inlet temperature gauge to begin to drop continuously.

[0118] The pressure drop in the gas cylinder is controlled at 69.3 seconds and 175.8 seconds. This embodiment controls the pressure of gas cylinder 9 as follows: Figure 5 .

[0119] At 192 seconds, the first phase ended, and T... ave It is still decreasing, but still above the lower limit of the target temperature. At this time, the pre-cooling discharge valve is still open.

[0120] 192 seconds later, the second stage begins, and the onboard computer 1 sends another command to the electric valve to open, continuing the continuous discharge.

[0121] After 192 seconds, since the precooling discharge valve 7 was previously open and there was high-pressure control gas in the control chamber of the precooling discharge valve 7, it was in the control gas supply state. Therefore, the pressure of the control gas cylinder 9 remained unchanged. At 212 seconds, the onboard computer 1 issued a closing command to the electric gas valve 8 again, closing the precooling discharge valve 7 and stopping the discharge of liquid oxygen.

[0122] Thus, the online control of intermittent emission during the coasting phase between two starts of the liquid oxygen kerosene engine was completed. The liquid oxygen inlet temperature of the engine was 83.1K, which is within the range of [82K, 93.15K], meeting the conditions required for the engine to restart.

[0123] The method of this invention improves the adaptability of existing emission control methods to different flight missions by real-time monitoring and dynamic optimization of intermittent emission timing, reduces propellant emission consumption, and improves the success rate and economy of rocket flight missions.

[0124] Example 2

[0125] Online control system for intermittent emissions from cryogenic engines, such as Figure 1 As shown, it includes a control gas cylinder 9, an electric gas valve 8 and a pre-cooling discharge valve 7 connected in sequence through pipelines; the pre-cooling discharge valve 7 is connected to the electric gas valve 8, the liquid oxygen main valve 6, the rocket liquid oxygen storage tank 11 and the discharge pipeline 12 through pipelines respectively.

[0126] It also includes an onboard computer 1 and a temperature sensor 4. The temperature sensor 4 is installed on a cryogenic pipeline 10 connected to the engine. The temperature sensor 4 is connected to the onboard computer 1 via a measuring cable 2. The electric air valve 8 is connected to the onboard computer 1 via a control cable 3.

[0127] Example 3

[0128] Online control system for intermittent emissions from cryogenic engines, such as Figure 1 As shown, it includes a control gas cylinder 9, an electric gas valve 8 and a pre-cooling discharge valve 7 connected in sequence through pipelines; the pre-cooling discharge valve 7 is connected to the electric gas valve 8, the liquid oxygen main valve 6, the rocket liquid oxygen storage tank 11 and the discharge pipeline 12 through pipelines respectively.

[0129] It also includes an onboard computer 1 and a temperature sensor 4. The temperature sensor 4 is installed on a cryogenic pipeline 10 connected to the engine. The temperature sensor 4 is connected to the onboard computer 1 via a measuring cable 2. The electric air valve 8 is connected to the onboard computer 1 via a control cable 3.

[0130] The precooling discharge valve 7 is a two-position three-way valve. The precooling discharge valve 7 is equipped with a control port 7-1, a cryogenic propellant inlet 7-2, a return port 7-3, and a discharge port 7-4. The control port 7-1 of the precooling discharge valve 7 is connected to the electric air valve 8 through a pipeline, the cryogenic propellant inlet 7-2 is connected to the liquid oxygen main valve 6 through a pipeline, the return port 7-3 is connected to the rocket liquid oxygen storage tank through a pipeline, and the discharge port 7-4 is directly connected to the atmosphere through a discharge pipeline.

[0131] Example 4

[0132] Online control system for intermittent emissions from cryogenic engines, such as Figure 1As shown, it includes a control gas cylinder 9, an electric gas valve 8 and a pre-cooling discharge valve 7 connected in sequence through pipelines; the pre-cooling discharge valve 7 is connected to the electric gas valve 8, the liquid oxygen main valve 6, the rocket liquid oxygen storage tank 11 and the discharge pipeline 12 through pipelines respectively.

[0133] It also includes an onboard computer 1 and a temperature sensor 4. The temperature sensor 4 is installed on a cryogenic pipeline 10 connected to the engine. The temperature sensor 4 is connected to the onboard computer 1 via a measuring cable 2. The electric air valve 8 is connected to the onboard computer 1 via a control cable 3.

[0134] The precooling discharge valve 7 is a two-position three-way valve. The precooling discharge valve 7 is equipped with a control port 7-1, a cryogenic propellant inlet 7-2, a return port 7-3, and a discharge port 7-4. The control port 7-1 of the precooling discharge valve 7 is connected to the electric air valve 8 through a pipeline, the cryogenic propellant inlet 7-2 is connected to the liquid oxygen main valve 6 through a pipeline, the return port 7-3 is connected to the rocket liquid oxygen storage tank through a pipeline, and the discharge port 7-4 is directly connected to the atmosphere through a discharge pipeline.

[0135] Electric valve 8 is a pilot-operated diaphragm solenoid valve.

[0136] Example 5

[0137] The online control method for intermittent emissions from cryogenic engines, employing the aforementioned online control system for intermittent emissions from cryogenic engines, is as follows:

[0138] Step 1: Before the cryogenic engine intermittent emission online control system is put into operation, the configuration parameters are injected into the onboard computer;

[0139] Step 2: Start the online control system for intermittent emissions from the low-temperature engine;

[0140] Step 3: The onboard computer 1 executes emission control according to the online emission control strategy.

[0141] Example 6

[0142] The online control method for intermittent emissions from cryogenic engines, employing the aforementioned online control system for intermittent emissions from cryogenic engines, is as follows:

[0143] Step 1: Before the cryogenic engine intermittent emission online control system is put into operation, the configuration parameters are injected into the onboard computer;

[0144] In step 1, the injection of configuration parameters is performed during the ground preparation phase before rocket launch. These configuration parameters include: the total duration t of the rocket's unpowered coasting phase. h Target temperature range [T1, T2], kb calibration coefficient of temperature sensor 4.

[0145] Step 2: Start the online control system for intermittent emissions from the low-temperature engine;

[0146] Step 3: The onboard computer 1 executes emission control according to the online emission control strategy.

Claims

1. A method for online control of intermittent emissions from a cryogenic engine, characterized in that, The cryogenic engine intermittent emission online control system is adopted. The cryogenic engine intermittent emission online control system includes a control gas cylinder (9), an electric gas valve (8) and a pre-cooling emission valve (7) connected in sequence through pipelines. The pre-cooling emission valve (7) is connected to the electric gas valve (8), the liquid oxygen main valve (6), the rocket liquid oxygen storage tank (11) and the emission pipeline (12) through pipelines respectively. It also includes an onboard computer (1) and a temperature sensor (4). The temperature sensor (4) is installed on a cryogenic pipeline (10) connected to the engine. The temperature sensor (4) is connected to the onboard computer (1) via a measuring cable (2). An electric air valve (8) is connected to the onboard computer (1) via a control cable (3). The method is specifically as follows: Step 1: Before the cryogenic engine intermittent emission online control system is put into operation, the configuration parameters are injected into the onboard computer; Step 2: Start the online control system for intermittent emissions from the low-temperature engine; Step 3: The onboard computer (1) executes emission control according to the online emission control strategy; In step 3, the specific online emission control strategy is as follows: 1) If the gliding time t h If the time is less than 20 seconds, formulate the following strategy: a) The onboard computer (1) sends a command to open the precooling discharge valve, and opens the precooling discharge valve (7) to perform continuous discharge; b) Interval t h Then, the onboard computer (1) sends a command to close the pre-cooling discharge valve (7), stopping the discharge, and the engine restarts; 2) If the gliding time t h If the time is ≥20 seconds, then t h Divided into two phases, the following strategy was formulated: a) The duration of the first phase is: t h -20 seconds, the second phase lasts for 20 seconds; b) In the first phase, a measurement and control cycle is defined as 300 milliseconds; c) The first 200 milliseconds of each measurement and control cycle are used for measurement. Temperature values ​​are collected through temperature sensor (4). Specifically, temperature values ​​are collected every 20 milliseconds within the first 200 milliseconds of each measurement and control cycle, i.e., the sampling frequency is 50Hz. The average of 10 measured temperatures is calculated to obtain T. ave ; d) The average temperature T obtained in step c) ave Compared with the target temperature range [T1, T2], if T ave If T2 is greater than or equal to T2, then send a command to open the precooling discharge valve (7) until T2 is reached. ave When T1 is less than or equal to 1, send a command to close the precooling discharge valve (7); e) In the last 100 milliseconds of each measurement and control cycle, the actuators of the electric air valve (8) and the pre-cooling discharge valve (7) are activated; according to the instructions in step d), in the last 100 milliseconds of each measurement and control cycle, the onboard computer (1) controls the electric air valve (8) to be energized or de-energized, so that the pre-cooling discharge valve (7) is opened or closed, thereby starting or stopping the discharge of cryogenic propellant. f) In the first stage, steps b) to e) are executed repeatedly in a 300-millisecond monitoring and control cycle until the remaining coasting time t is reached. h剩余 <20 seconds; g) In the second stage, i.e. when the remaining taxiing time t h剩余 If the time is less than 20 seconds, send the command to open the pre-cooling discharge valve (7) again to perform continuous discharge; h) After continuous emission is completed, the onboard computer (1) sends a command to close the pre-cooled emission valve (7) to stop emission and the engine restarts.

2. The online control method for intermittent emissions from a cryogenic engine according to claim 1, characterized in that, In step 1, the injection of configuration parameters is performed during the ground preparation phase before rocket launch. These configuration parameters include: the total duration t of the rocket's unpowered coasting phase. h The target temperature range [T1, T2] and the kb calibration coefficient of the temperature sensor (4).

3. The online control method for intermittent emissions from a cryogenic engine according to claim 1, characterized in that, In step 2, the low-temperature engine intermittent emission online control system is initially in a stopped emission state, and the pre-cooled emission valve (7) is in a closed state; When the onboard computer (1) sends the engine shutdown command, it immediately enters the emission control stage and the low-temperature engine intermittent emission online control system is activated.

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