A multi-parameter correlation ramjet engine fault diagnosis system and method

Abstract

This invention belongs to the field of engine fault diagnosis, specifically relating to a multi-parameter correlation-based fault diagnosis system and method for ramjet engines, including a control system and detection equipment. The control system includes a valve not-opening identification and processing module, a flameout detection and secondary ignition module, and an over-temperature / over-pressure protection module. This invention designs a multi-parameter correlation-based fault diagnosis system for ramjet engines, enabling it to autonomously identify and handle abnormal phenomena that may occur during operation, such as valve not-opening, ignition failure, and structural over-temperature / over-pressure, thereby significantly improving operational reliability. Furthermore, the system employs multi-parameter correlation sensing, not relying on a single measuring component or data, solving the problem of false positives and false negatives caused by sensor failure in single-parameter discrimination, ensuring reliability and significantly improving engine robustness. Moreover, parameters can be reused between modules, reducing redundant calculations and simplifying the system.

Description

Technical Field

[0001] This invention belongs to the field of engine fault diagnosis, specifically relating to a multi-parameter correlation ramjet engine fault diagnosis system and method. Background Technology

[0002] The operation of an engine is complex, involving multiple stages such as fuel supply, ignition, and structural thermal protection. A malfunction in any of these stages can lead to abnormal engine conditions and serious consequences. Therefore, designing a diagnostic system for the engine to improve its reliability is essential.

[0003] Common engine diagnostic systems often suffer from the following problems: reliance on a single sensor, high false alarm rate, and the need for manual intervention in handling some faults, leading to delayed response. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a fault diagnosis system and method for ramjet engines with multi-parameter correlation.

[0005] This invention provides a multi-parameter correlation ramjet engine fault diagnosis system, including control rate and detection equipment;

[0006] The control system includes a valve not-opening identification and processing module, a flameout detection and secondary ignition module, and an over-temperature / over-pressure protection module;

[0007] The valve not-opening identification and processing module includes a valve not-opening judgment model. This model calculates the theoretical values ​​of pre-spray pressure, post-pump pressure, and motor speed, and uses these as inputs to correlate and analyze the measured values ​​of pre-spray pressure, post-pump pressure, and motor speed obtained by the detection equipment to determine whether the valve is open. If the valve is successfully opened, the engine enters the ignition stage; if the valve fails to open, a backup valve is opened.

[0008] The flameout detection and secondary ignition module includes a flameout detection model. This model directly calls the theoretical value of the pre-injection pressure calculated by the valve not-open detection model and uses it as input. It also considers the rate of increase of the pre-injection pressure, combustion chamber pressure, and outlet oil temperature obtained by the detection equipment to comprehensively determine whether ignition has failed. If ignition is determined to be successful, the engine enters steady-state operation. If ignition is determined to have failed, it is determined whether secondary ignition conditions are met, and the secondary ignition timing of the backup igniter is selected based on the secondary ignition conditions.

[0009] The over-temperature / over-pressure protection module includes an over-temperature / over-pressure judgment model. This module calculates the theoretical threshold values ​​of outlet oil pressure and pump post-pressure, and uses these as inputs to correlate and analyze the measured values ​​of outlet oil temperature, outlet oil pressure, and pump post-pressure obtained by the detection equipment to determine whether over-temperature / over-pressure occurs. If no over-temperature / over-pressure is detected, the engine operates normally. If over-temperature / over-pressure is detected, the fuel flow is increased and the backup hot oil valve is opened.

[0010] The valve not open judgment model and the over-temperature / over-pressure protection module share the pipeline friction loss calculation model, which is used to calculate the theoretical value of the pump downstream pressure and the theoretical threshold of the pump downstream pressure, respectively.

[0011] Furthermore, the valve not-opening judgment model includes a calculation model for the theoretical value of the pre-pump pressure, an initial calculation model for the theoretical value of the post-pump pressure, a conversion model for the theoretical value of the post-pump pressure, a calculation model for the pipeline friction loss, and a calculation model for the theoretical value of the motor speed.

[0012] The theoretical calculation model for pre-spray pressure is as follows:

[0013] ;

[0014] in, This is the theoretical value of the pre-spray pressure. For fuel flow rate, The nozzle flow rate coefficient is... The nozzle area is... The density of fuel;

[0015] The initial model for calculating the theoretical value of the pump back pressure is as follows:

[0016] ;

[0017] in, This is the theoretical value of the pump's post-pressure. This is the theoretical value of the pre-spray pressure. Friction loss along the pipeline;

[0018] The pipeline friction loss calculation model is as follows:

[0019] ;

[0020] in, The drag coefficient, For the length of the pipe, The hydraulic diameter, For fuel density, For flow rate;

[0021] The theoretical value calculation conversion model for pump back pressure is as follows:

[0022] ;

[0023] The theoretical calculation model for motor speed is as follows:

[0024] ;

[0025] in, This is the theoretical value of fuel flow. , , The fitting coefficients were obtained by fitting the oil pumping test data of the motor pump. This refers to the motor speed. This is the theoretical value of the pump's post-pressure. This is the pressure before the pump.

[0026] Furthermore, the valve not-open identification and processing module performs correlation analysis, including:

[0027] If the measured value of the pump post-pressure is greater than or equal to (1+30%) of the theoretical value of the pump post-pressure, the valve is judged to have failed to open; otherwise, the valve is judged to have opened successfully.

[0028] If the measured pre-spray pressure is less than 30% of the theoretical pre-spray pressure, the valve is considered to have failed to open; otherwise, the valve is considered to have opened successfully.

[0029] If the measured speed deviates from the theoretical motor speed by more than or equal to 30%, the valve is deemed to have failed to open; otherwise, the valve is deemed to have opened successfully.

[0030] Furthermore, if the number of valve opening failures is greater than or equal to 2, the valve is ultimately deemed to have failed to open, and a backup valve is opened.

[0031] Furthermore, the flameout judgment model includes a calculation model for the theoretical value of the pre-injection pressure.

[0032] Furthermore, the correlation analysis between the flameout detection and the secondary ignition module includes:

[0033] If the measured value of the pre-spray pressure minus the theoretical value of the pre-spray pressure is less than or equal to 150 kPa, the ignition is considered to have failed; otherwise, the ignition is considered to have succeeded.

[0034] When the combustion chamber pressure is less than or equal to 80 kPa, ignition is considered to have failed; otherwise, ignition is considered to have succeeded.

[0035] If the outlet oil temperature rise rate is less than or equal to 5℃ / s, the ignition is considered to have failed; otherwise, the ignition is considered to have succeeded.

[0036] The rate of temperature rise of the outlet oil is obtained by the detection equipment.

[0037] Furthermore, if the number of ignition failures is greater than or equal to 2, then the ignition is ultimately determined to be a failure, and it is determined whether the conditions for secondary ignition are met. Based on the conditions for secondary ignition, the timing for secondary ignition of the backup igniter is selected.

[0038] Determining whether secondary ignition conditions are met, and selecting the secondary ignition timing for the backup igniter based on these conditions, includes:

[0039] Condition 1: If the measured value of the pre-spray pressure is greater than or equal to 80% of the theoretical value of the pre-spray pressure, the backup igniter will be directly triggered for secondary ignition.

[0040] Condition 2: If the measured fuel flow rate is greater than or equal to 80% of the theoretical fuel flow rate, the backup igniter will be directly triggered for secondary ignition.

[0041] If conditions one and two are not met, wait for 2 seconds and trigger the backup igniter for secondary ignition.

[0042] Furthermore, the over-temperature / over-pressure judgment model includes a theoretical threshold calculation model for outlet oil pressure and a theoretical threshold calculation model for post-pump pressure;

[0043] The theoretical threshold calculation model for outlet oil pressure is as follows:

[0044] ;

[0045] in, This is the theoretical value of fuel flow. , These are the fitting coefficients. This is the theoretical threshold temperature for the outlet oil. The nozzle area is... This represents the theoretical threshold value for the outlet oil pressure.

[0046] The theoretical threshold calculation model for pump post-pressure is as follows:

[0047] ;

[0048] in, P b0 This is the theoretical threshold value for the pump's post-pump pressure. This is the theoretical threshold value for the outlet oil pressure. The friction loss along the pipeline can be calculated using a pipeline friction loss calculation model.

[0049] Furthermore, the over-temperature / over-pressure protection module performs correlation analysis, including:

[0050] When the measured value of the outlet oil temperature is greater than or equal to the theoretical threshold of the outlet oil temperature, it is judged as over-temperature / over-pressure; otherwise, it is judged as structurally safe.

[0051] When the measured value of the outlet oil pressure is greater than or equal to the theoretical threshold of the outlet oil pressure, it is determined to be over-temperature / over-pressure; otherwise, it is determined to be structurally safe.

[0052] When the measured value of the pump post-pressure is greater than or equal to the theoretical threshold of the pump post-pressure, it is judged as over-temperature / over-pressure; otherwise, it is judged as structurally safe.

[0053] If the number of over-temperature / over-pressure events is greater than or equal to 2, then the over-temperature / over-pressure event is finally determined, the fuel flow is increased, and the backup hot oil valve is opened.

[0054] The present invention also provides a multi-parameter correlation ramjet engine fault diagnosis method, which uses the above-mentioned multi-parameter correlation ramjet engine fault diagnosis system to diagnose engine faults.

[0055] The beneficial effects of this invention are that it designs a multi-parameter correlation fault diagnosis system for ramjet engines. This system can autonomously identify and handle abnormal phenomena that may occur during operation, such as valves not opening, ignition failure, and structural overheating / overpressure, thereby significantly improving operational reliability. Furthermore, the system employs multi-parameter correlation sensing, eliminating reliance on single measuring components and data. This solves the problem of false positives and false negatives caused by sensor failure when judging single parameters, ensuring reliability and significantly improving engine robustness. Additionally, parameters can be reused between modules, reducing redundant calculations and simplifying the system. Attached Figure Description

[0056] Appendix Figure 1 It is a structural schematic diagram of the present invention;

[0057] Appendix Figure 2 This is a hardware schematic diagram of the valve not-open identification and processing module in this invention;

[0058] Appendix Figure 3 This is a logic diagram of the valve not-open identification and processing module in this invention.

[0059] Appendix Figure 4 This is a hardware schematic diagram of the flameout detection and secondary ignition module in this invention;

[0060] Appendix Figure 5 This is a logic diagram of the flameout detection and secondary ignition module in this invention;

[0061] Appendix Figure 6 This is a hardware schematic diagram of the over-temperature / over-pressure protection module in this invention;

[0062] Appendix Figure 7 This is the logic diagram of the over-temperature / over-pressure protection module in this invention. Detailed Implementation

[0063] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0064] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0065] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0066] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0067] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0068] As attached Figure 1 - Appendix Figure 7 As shown, this invention provides a multi-parameter correlation ramjet engine fault diagnosis system, including a control rate and detection equipment. The control rate is used to design the timing, elements, values, judgment rules, and fault handling measures for condition monitoring. The detection equipment includes an engine integrated controller, pressure / temperature sensors, valves, an igniter, and a fuel pump, used to sense the engine status, make decisions, and execute corresponding actions.

[0069] The main types of faults occurring at different stages of engine operation are as follows: During engine start-up, the main problem is the inability of the injection valve to open, resulting in no fuel entering the combustion chamber and thus ignition failure; during the ignition stage, the main risk is igniter failure leading to ignition failure; during steady-state cruising, the main risk is overheating and overpressure of the cooling structure. Therefore, the control mechanism of this invention includes a valve not-opening identification and processing module, a flameout detection and secondary ignition module, and an over-temperature / over-pressure protection module.

[0070] The valve not-opening identification and processing module includes a valve not-opening judgment model. This model calculates the theoretical values ​​of pre-spray pressure, post-pump pressure, and motor speed, and uses these as inputs to correlate and analyze the measured values ​​of pre-spray pressure, post-pump pressure, and motor speed obtained by the detection equipment to determine whether the valve is open. If the valve is successfully opened, the engine enters the ignition stage; if the valve fails to open, a backup valve is opened.

[0071] The flameout detection and secondary ignition module includes a flameout detection model. This model directly calls the theoretical value of the pre-injection pressure calculated by the valve not-open detection model and uses it as input. It also considers the rate of increase of the pre-injection pressure, combustion chamber pressure, and outlet oil temperature obtained by the detection equipment to comprehensively determine whether ignition has failed. If ignition is determined to be successful, the engine enters steady-state operation. If ignition is determined to have failed, it is determined whether secondary ignition conditions are met, and the secondary ignition timing of the backup igniter is selected based on the secondary ignition conditions.

[0072] The over-temperature / over-pressure protection module includes an over-temperature / over-pressure judgment model. This module calculates the theoretical threshold values ​​for outlet oil temperature, outlet oil pressure, and post-pump pressure, and uses these as inputs to correlate and analyze the measured values ​​of outlet oil temperature, outlet oil pressure, and post-pump pressure obtained by the detection equipment to determine whether over-temperature / over-pressure occurs. If no over-temperature / over-pressure is detected, the engine operates normally. If over-temperature / over-pressure is detected, the fuel flow is increased and the backup hot oil valve is opened.

[0073] The valve not open judgment model and the over-temperature / over-pressure protection module share the pipeline friction loss calculation model, which is used to calculate the theoretical value of the pump downstream pressure and the theoretical threshold of the pump downstream pressure, respectively.

[0074] This invention addresses the fault diagnosis of ramjet engines by designing a multi-parameter correlation system. This system enables the engine to autonomously identify and handle abnormal phenomena that may occur during operation, such as valves not opening, ignition failure, and structural overheating / overpressure, significantly improving operational reliability. Furthermore, the system employs multi-parameter correlation sensing, eliminating reliance on single measuring components and data. This solves the problem of false positives and false negatives caused by sensor failure when judging single parameters, ensuring reliability and significantly improving engine robustness. Additionally, the system allows for parameter reuse between modules, reducing redundant calculations and simplifying the system.

[0075] In one embodiment, the valve not-opening determination model includes a calculation model for the theoretical value of the pre-pump pressure, an initial calculation model for the theoretical value of the post-pump pressure, a conversion model for the theoretical value of the post-pump pressure, a pipeline friction loss calculation model, and a motor speed theoretical value calculation model.

[0076] The theoretical calculation model for pre-spray pressure is as follows:

[0077] ;

[0078] in, This is the theoretical value of the pre-spray pressure. This is the theoretical value of fuel flow. The nozzle flow rate coefficient is... The nozzle area is... The density of fuel;

[0079] The initial model for calculating the theoretical value of the pump back pressure is as follows:

[0080] ;

[0081] in, This is the theoretical value of the pump's post-pressure. This is the theoretical value of the pre-spray pressure. Friction loss along the pipeline;

[0082] The pipeline friction loss calculation model is as follows:

[0083] ;

[0084] in, The drag coefficient, For the length of the pipe, The hydraulic diameter, For fuel density, For flow rate;

[0085] The theoretical value calculation conversion model for pump back pressure is as follows:

[0086] ;

[0087] The theoretical calculation model for motor speed is as follows:

[0088] ;

[0089] in, This is the theoretical value of fuel flow. , , The fitting coefficients were obtained by fitting the oil pumping test data of the motor pump. This refers to the motor speed. This is the theoretical value of the pump's post-pressure. This is the pressure before the pump.

[0090] In this embodiment, the valve status determination method utilizes five interconnected calculation models working collaboratively: a pre-injection pressure theoretical value calculation model calculates the theoretical pressure before fuel injection; a post-pump pressure theoretical value calculation initial model calculates the theoretical pressure at the pump outlet (considering pipeline flow losses); a pipeline friction loss calculation model optimizes the post-pump pressure value; a post-pump pressure theoretical value calculation conversion model specifically calculates pipeline losses; and a motor speed theoretical value calculation model calculates the theoretical motor speed. These models ensure consistent calculation results by sharing key parameters (such as fuel flow rate), and then compare these results with actual sensor measurements to comprehensively determine whether the valve is open. The entire determination process is logically clear, efficient, and fast, with a detection efficiency faster than traditional methods, and immediately activates a backup valve when the valve is determined to be open but fails to open.

[0091] In one embodiment, the valve not-open identification and processing module performs the following correlation analysis:

[0092] If the measured value of the pump post-pressure is greater than or equal to (1+30%) of the theoretical value of the pump post-pressure, the valve is judged to have failed to open; otherwise, the valve is judged to have opened successfully.

[0093] If the measured pre-spray pressure is less than 30% of the theoretical pre-spray pressure, the valve is considered to have failed to open; otherwise, the valve is considered to have opened successfully.

[0094] If the measured speed deviates from the theoretical motor speed by more than or equal to 30%, the valve is deemed to have failed to open; otherwise, the valve is deemed to have opened successfully.

[0095] In this embodiment, multiple judgment processes are used to make judgments, which can greatly improve the accuracy of judgments and reduce misjudgments.

[0096] In one embodiment, if the number of valve opening failures is greater than or equal to two, the valve is ultimately determined to have failed to open, and a backup valve is opened. In this embodiment, if two or more fault flags are accumulated, the valve is ultimately determined to have failed to open, and the backup valve switching procedure is immediately initiated to reduce the risk of malfunction caused by false alarms from a single device.

[0097] In one embodiment, the flameout determination model includes a model for calculating the theoretical value of the injection pre-pressure:

[0098] The theoretical calculation model for pre-spray pressure is as follows:

[0099] .

[0100] In one embodiment, the correlation analysis between the flameout detection and the secondary ignition module includes:

[0101] If the measured value of the pre-spray pressure minus the theoretical value of the pre-spray pressure is less than or equal to 150 kPa, the ignition is considered to have failed; otherwise, the ignition is considered to have succeeded.

[0102] When the combustion chamber compaction measurement value is less than or equal to 80 kPa, ignition is considered to have failed; otherwise, ignition is considered to have succeeded.

[0103] If the outlet oil temperature rise rate is less than or equal to 5℃ / s, the ignition is considered to have failed; otherwise, the ignition is considered to have succeeded.

[0104] The rate of temperature rise of the outlet oil is obtained by the detection equipment.

[0105] In one embodiment, after determining that the number of ignition failures is greater than or equal to 2, the ignition is finally determined to be failed, and it is determined whether the conditions for secondary ignition are met. Based on the conditions for secondary ignition, the timing for secondary ignition of the backup igniter is selected.

[0106] Determining whether secondary ignition conditions are met, and selecting the secondary ignition timing for the backup igniter based on these conditions, includes:

[0107] Condition 1: If the measured value of the pre-spray pressure is greater than or equal to 80% of the theoretical value of the pre-spray pressure, the backup igniter will be directly triggered for secondary ignition.

[0108] Condition 2: If the measured fuel flow rate is greater than or equal to 80% of the theoretical fuel flow rate, the backup igniter will be directly triggered for secondary ignition.

[0109] If conditions one and two are not met, wait for 2 seconds and trigger the backup igniter for secondary ignition.

[0110] In this embodiment, the flameout detection scheme achieves millisecond-level accurate diagnosis through a triple dynamic threshold joint prevention mechanism: when the combustion chamber pressure drops below 80 kPa, or the pre-injection pressure difference is below 150 kPa, or the oil temperature rise rate is below 5℃ / s, the fault is immediately marked when any abnormality occurs; finally, a breakthrough improvement in the success rate of fault handling is achieved through a secondary ignition graded response strategy (immediate trigger when the pre-injection pressure is ≥80% of the theoretical value, second-level ignition when the flow rate meets the standard, and a minimum 2-second delay for abnormal conditions).

[0111] In one embodiment, the over-temperature / over-pressure judgment model includes a theoretical threshold calculation model for outlet oil pressure and a theoretical threshold calculation model for pump post-pump pressure.

[0112] The theoretical threshold calculation model for outlet oil pressure is as follows:

[0113] ;

[0114] in, This is the theoretical value of fuel flow. , These are the fitting coefficients. The theoretical threshold temperature for the outlet oil is denoted as , which is a given constant. The nozzle area is... This represents the theoretical threshold value for the outlet oil pressure.

[0115] The theoretical threshold calculation model for pump post-pressure is as follows:

[0116] ;

[0117] in, P b0 This is the theoretical threshold value for the pump's post-pump pressure. This is the theoretical threshold value for the outlet oil pressure. The friction loss along the pipeline can be calculated using a pipeline friction loss calculation model.

[0118] In one embodiment, the over-temperature / over-pressure protection module performs correlation analysis including:

[0119] When the measured value of the outlet oil temperature is greater than or equal to the theoretical threshold of the outlet oil temperature, it is judged as over-temperature / over-pressure; otherwise, it is judged as structurally safe.

[0120] When the measured value of the outlet oil pressure is greater than or equal to the theoretical threshold of the outlet oil pressure, it is determined to be over-temperature / over-pressure; otherwise, it is determined to be structurally safe.

[0121] When the measured value of the pump post-pressure is greater than or equal to the theoretical threshold of the pump post-pressure, it is judged as over-temperature / over-pressure; otherwise, it is judged as structurally safe.

[0122] If the number of over-temperature / over-pressure events is greater than or equal to 2, then the over-temperature / over-pressure event is finally determined, the fuel flow is increased, and the backup hot oil valve is opened.

[0123] In this embodiment, the threshold is calibrated in real time by reusing the fuel flow parameters; when any two of the outlet oil temperature, outlet oil pressure, and post-pump pressure exceed the limit, a double insurance response is immediately triggered, dynamically adjusting the fuel pump flow to enhance cooling, and linking with the backup hot oil valve to reduce pressure, ensuring normal engine operation.

[0124] This invention provides a specific embodiment where the main fault types occurring at different stages of engine operation are as follows: During engine start-up, the main fault is the inability of the injection valve to open, resulting in no fuel entering the combustion chamber and thus ignition failure; during the ignition stage, the main risk is ignition failure due to igniter malfunction; during steady-state cruising, the main risk is overheating and overpressure of the cooling structure. Therefore, this invention designs a valve not-opening identification and processing module, a flameout detection and secondary ignition module, and an over-temperature / over-pressure protection module, as detailed below:

[0125] The valve not-open identification and handling module is used for valve not-opening identification and handling functions: After the engine fuel pump starts running and fuel supply begins, the valve fault identification and handling function is activated, and the system begins monitoring the pre-injection pressure, post-pump pressure, and motor speed. If the injection valve is normally open, fuel will flow from after the pump through the fuel supply line, cold fuel valve, and accumulator chamber, and finally be injected into the combustion chamber through the injection orifice. The hardware components are as follows: Figure 2 As shown, a calculation model for the theoretical value of the pre-spray pressure is established as follows:

[0126] (1)

[0127] This is the theoretical value of the pre-spray pressure. This is the theoretical value of fuel flow. The nozzle flow rate coefficient is... The nozzle area is... The density of fuel;

[0128] The post-pump pressure is the sum of the pre-pump pressure and the friction loss. An initial model for calculating the theoretical value of the post-pump pressure can be established as follows:

[0129] (2)

[0130] in, This is the theoretical value of the pump's post-pressure. The theoretical value of the pre-spray pressure can be calculated using model (1). The friction loss along the pipeline is calculated using the following model:

[0131] (3)

[0132] in, The drag coefficient, For the length of the pipe, The hydraulic diameter, For fuel density, Flow rate.

[0133] Therefore, the conversion model for calculating the theoretical value of the pump's downstream pressure is as follows:

[0134] (4)

[0135] Once the cold oil valve is open normally and the flow path is established, the fuel pump motor speed is related to the load, i.e., the fuel flow rate and the post-pump pressure. Therefore, the theoretical calculation model for the motor speed is as follows:

[0136] (5)

[0137] in, This is the theoretical value of fuel flow. , , The fitting coefficients were obtained by fitting the oil pumping test data of the motor pump. This refers to the motor speed. This is the theoretical value of the pump's post-pressure. The pressure before the pump can be approximated as equal to the pressure in the fuel tank.

[0138] After the valve not open identification and processing module is activated, the system begins to calculate the pump downstream pressure based on model (4), model (1), and model (5). Pre-spray pressure Rotation speed The theoretical value, and compared with the sensor's measured value. , , A comparison is then made. After comprehensively analyzing the three parameters, a final determination is made as to whether the valve should be opened.

[0139] Specific judgment reference Figure 3 If the measured value of the pump post-pressure is greater than or equal to (1+30%) of the theoretical value of the pump post-pressure, the valve is judged to have failed to open; otherwise, the valve is judged to have opened successfully.

[0140] If the measured pre-spray pressure is less than 30% of the theoretical pre-spray pressure, the valve is considered to have failed to open; otherwise, the valve is considered to have opened successfully.

[0141] If the measured speed deviates from the theoretical motor speed by more than or equal to 30%, the valve is deemed to have failed to open; otherwise, the valve is deemed to have opened successfully.

[0142] If the valve fails to open, the backup valve is immediately opened, and then the engine starts ignition. If the valve opens normally, the engine enters the ignition phase, and the valve failure identification and processing module is shut down.

[0143] The flameout detection and secondary ignition module is used for flameout detection and secondary ignition functions: After normal fuel supply and pre-injection pressure are established, the engine can begin ignition. The control system issues an ignition command, the igniter operates, and ignites the air-fuel mixture. At this time, the flameout detection and secondary ignition function is activated. The hardware components are as follows: Figure 4As shown, the system begins monitoring the combustion chamber pressure, pre-injection pressure, and flow channel outlet oil temperature. If ignition is successful, pressure will build up in the combustion chamber, the magnitude of which can be estimated from simulation or ground test results, generally greater than 150 kPa; if ignition fails, the combustion chamber pressure will be much lower than the estimated value, generally less than 80 kPa. Simultaneously, after successful ignition, due to the presence of combustion chamber back pressure, the pre-injection pressure will also rise; subtracting the theoretical value from this rise gives the combustion chamber pressure.

[0144] After successful ignition, the oil temperature at the flow channel outlet begins to rise rapidly, typically at a rate greater than 20°C / s. If ignition fails, the oil temperature at the flow channel outlet changes very little due to the lack of combustion heating, with a rate of temperature rise typically less than 5°C / s.

[0145] The system starts to calculate the theoretical value of the pre-injection pressure according to model (1) and combines the measured value of the pre-injection pressure, the measured value of the combustion chamber pressure, and the measured value of the outlet oil temperature to comprehensively judge whether the ignition has failed.

[0146] The specific judgment logic is as follows: Figure 5 As shown.

[0147] If the measured value of the pre-spray pressure minus the theoretical value of the pre-spray pressure is less than or equal to 150 kPa, the ignition is considered to have failed; otherwise, the ignition is considered to have succeeded.

[0148] When the combustion chamber pressure is less than or equal to 80 kPa, ignition is considered to have failed; otherwise, ignition is considered to have succeeded.

[0149] If the outlet oil temperature rise rate is less than or equal to 5℃ / s, the ignition is considered to have failed; otherwise, the ignition is considered to have succeeded.

[0150] If the number of ignition failures is greater than or equal to 2, the ignition is ultimately determined to be failed, and it is then determined whether the conditions for secondary ignition are met. Based on the conditions for secondary ignition, the timing for secondary ignition of the backup igniter is selected.

[0151] Determining whether secondary ignition conditions are met, and selecting the secondary ignition timing for the backup igniter based on these conditions, includes:

[0152] Condition 1: If the measured value of the pre-spray pressure is greater than or equal to 80% of the theoretical value of the pre-spray pressure, the backup igniter will be directly triggered for secondary ignition.

[0153] Condition 2: If the measured value of fuel flow is greater than or equal to 80% of the theoretical value of fuel flow (calculated by model 5), the backup igniter will be directly triggered for secondary ignition.

[0154] If conditions one and two are not met, wait for 2 seconds and trigger the backup igniter for secondary ignition. Afterward, the engine enters a steady-state operating phase, and the engine shutdown detection and secondary ignition module functions are disabled.

[0155] Over-temperature / over-pressure protection module: After the engine enters steady-state operation, the over-temperature / over-pressure protection module is activated. Its hardware components are as follows: Figure 6 As shown. The system begins monitoring the cooling channel outlet oil temperature, outlet oil pressure, and post-pump pressure. The outlet oil temperature and outlet oil pressure are determined by the state of the fuel cracked gas, and the two are correlated. Therefore, a theoretical threshold calculation model for the outlet oil pressure can be constructed, as follows:

[0156] (7)

[0157] in, This is the theoretical value of fuel flow. , These are the fitting coefficients. This is the theoretical threshold temperature for the outlet oil. The nozzle area is... This is the theoretical threshold value for the outlet oil pressure.

[0158] The pump post-pressure is the sum of the outlet oil pressure and the pipeline friction loss. Therefore, a theoretical threshold calculation model for the pump post-pressure can be constructed as follows:

[0159] (8)

[0160] in, P b0 This is the theoretical threshold value for the pump's post-pump pressure. This is the theoretical threshold value for the outlet oil pressure. The friction loss along the pipeline can be calculated using model (3).

[0161] The theoretical threshold for the given outlet oil temperature Then, the theoretical threshold of the outlet oil pressure can be calculated based on model (7) and model (8). Theoretical threshold of pump post-pressure And compared with the sensor's measured value. , A comparison is then made. After comprehensively analyzing the three parameters, a final determination is made as to whether the temperature / pressure is excessive.

[0162] The specific judgment logic is as follows: Figure 7 As shown. When the measured value of the outlet oil temperature is greater than or equal to the theoretical threshold of the outlet oil temperature, it is determined to be over-temperature / over-pressure; otherwise, it is determined to be structurally safe.

[0163] When the measured value of the outlet oil pressure is greater than or equal to the theoretical threshold of the outlet oil pressure, it is determined to be over-temperature / over-pressure; otherwise, it is determined to be structurally safe.

[0164] When the measured value of the pump post-pressure is greater than or equal to the theoretical threshold of the pump post-pressure, it is judged as over-temperature / over-pressure; otherwise, it is judged as structurally safe.

[0165] If the number of over-temperature / over-pressure events is greater than or equal to 2, then the over-temperature / over-pressure event is finally determined, the fuel flow is increased, and the backup hot oil valve is opened.

[0166] The hardware components of this invention include a controller, a detection device, and execution hardware:

[0167] The controller includes the engine integrated controller. Its main functions are to receive temperature, pressure, and flow meter signals, and to determine the engine status based on control logic. If a certain type of fault is detected, it sends a signal to the fuel pump, ignition system, valves, and other actuators to perform corresponding operations.

[0168] For testing equipment, please refer to Figure 2 , Figure 4 and Figure 5 The system includes: a pressure sensor to measure pump post-pressure, outlet fuel pressure, pre-injection pressure, and combustion chamber pressure, providing data for system fault diagnosis; a flow meter to measure fuel flow rate, providing data for calculating theoretical values ​​of parameters such as pre-injection pressure; and a temperature sensor to measure the oil temperature at the engine cooling system outlet, providing data for system fault diagnosis.

[0169] For hardware implementation details, please refer to [reference]. Figure 2 , Figure 4 and Figure 6 This includes: a fuel pump: used to regulate kerosene flow. When the system detects overheating / overpressure in the structure, it increases the fuel flow for cooling. A cold oil valve assembly: composed of multiple cold oil valves, used to inject cold oil into the combustion chamber for ignition. If the system detects a valve malfunction, a backup valve opens. A hot oil valve assembly: composed of multiple hot oil valves, used to regulate the flow of hot oil through the cooling structure and the hot oil injected into the combustion chamber. If the system detects overheating / overpressure in the structure, a backup hot oil valve opens to reduce pressure. An igniter: used for engine ignition.

[0170] The present invention also provides a multi-parameter correlation ramjet engine fault diagnosis method, which uses the above-mentioned multi-parameter correlation ramjet engine fault diagnosis system to diagnose engine faults.

[0171] The above description is merely an embodiment and does not constitute any limitation on the present invention. Any person skilled in the art can make many possible variations, modifications, or alterations to the technical solutions of the present invention without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, should fall within the protection scope of the present invention.

Claims

1. A multi-parameter correlation ramjet engine fault diagnosis system, characterized in that, This includes control rates and testing equipment; The control system includes a valve not-opening identification and processing module, a flameout detection and secondary ignition module, and an over-temperature / over-pressure protection module; The valve not-opening identification and processing module includes a valve not-opening judgment model. This model calculates the theoretical values ​​of pre-spray pressure, post-pump pressure, and motor speed, and uses these as inputs to correlate and analyze the measured values ​​of pre-spray pressure, post-pump pressure, and motor speed obtained by the detection equipment to determine whether the valve is open. If the valve is successfully opened, the engine enters the ignition stage; if the valve fails to open, a backup valve is opened. The flameout detection and secondary ignition module includes a flameout detection model. This model directly calls the theoretical value of the pre-injection pressure calculated by the valve not-open detection model and uses it as input. It also considers the rate of increase of the pre-injection pressure, combustion chamber pressure, and outlet oil temperature obtained by the detection equipment to comprehensively determine whether ignition has failed. If ignition is determined to be successful, the engine enters steady-state operation. If ignition is determined to have failed, it is determined whether secondary ignition conditions are met, and the secondary ignition timing of the backup igniter is selected based on the secondary ignition conditions. The over-temperature / over-pressure protection module includes an over-temperature / over-pressure judgment model. The over-temperature / over-pressure judgment module calculates the theoretical threshold values ​​of outlet oil temperature, outlet oil pressure, and pump post-pressure, and uses these as inputs to correlate and analyze the measured values ​​of outlet oil temperature, outlet oil pressure, and pump post-pressure obtained by the detection equipment to determine whether over-temperature / over-pressure has occurred. If no overheating / overpressure is detected, the engine operates normally; if overheating / overpressure is detected, the fuel flow is increased and the backup hot oil valve is opened. The valve not open judgment model and the over-temperature / over-pressure protection module share the pipeline friction loss calculation model, which is used to calculate the theoretical value of the pump downstream pressure and the theoretical threshold of the pump downstream pressure, respectively.

2. The multi-parameter correlation ramjet engine fault diagnosis system as described in claim 1, characterized in that, The valve not-opening judgment model includes a calculation model for the theoretical value of the pre-pump pressure, an initial calculation model for the theoretical value of the post-pump pressure, a conversion model for the theoretical value of the post-pump pressure, a pipeline friction loss calculation model, and a motor speed theoretical value calculation model. The theoretical calculation model for pre-spray pressure is as follows: ； in, This is the theoretical value of the pre-spray pressure. This is the theoretical value of fuel flow. The nozzle flow rate coefficient is... The nozzle area is... The density of fuel; The initial model for calculating the theoretical value of the pump back pressure is as follows: ； in, This is the theoretical value of the pump's post-pressure. This is the theoretical value of the pre-spray pressure. Friction loss along the pipeline; The pipeline friction loss calculation model is as follows: ； in, The drag coefficient, For the length of the pipe, The hydraulic diameter, For fuel density, For flow rate; The theoretical value calculation conversion model for pump back pressure is as follows: ； The theoretical calculation model for motor speed is as follows: ； in, This is the theoretical value of fuel flow. , , The fitting coefficients were obtained by fitting the oil pumping test data of the motor pump. This refers to the motor speed. This is the theoretical value of the pump's post-pressure. This is the pressure before the pump.

3. The multi-parameter correlation ramjet engine fault diagnosis system as described in claim 2, characterized in that, The valve not-open identification and processing module performs correlation analysis, including: If the measured value of the pump post-pressure is greater than or equal to (1+30%) of the theoretical value of the pump post-pressure, the valve is judged to have failed to open; otherwise, the valve is judged to have opened successfully. If the measured value of the pre-spray pressure is less than 30% of the theoretical value of the pre-spray pressure, the valve is judged to have failed to open; otherwise, the valve is judged to have opened successfully. If the measured speed deviates from the theoretical motor speed by more than or equal to 30%, the valve is deemed to have failed to open; otherwise, the valve is deemed to have opened successfully.

4. The multi-parameter correlation ramjet engine fault diagnosis system as described in claim 3, characterized in that, If the number of valve opening failures is greater than or equal to 2, the valve is ultimately deemed to have failed to open, and a backup valve is opened.

5. The multi-parameter correlation ramjet engine fault diagnosis system as described in claim 2, characterized in that, The engine shutdown judgment model includes a calculation model based on the theoretical value of the pre-injection pressure.

6. The multi-parameter correlation ramjet engine fault diagnosis system as described in claim 5, characterized in that, The correlation analysis between the flameout detection and secondary ignition module includes: If the measured value of the pre-spray pressure minus the theoretical value of the pre-spray pressure is less than or equal to 150 kPa, the ignition is considered to have failed; otherwise, the ignition is considered to have succeeded. When the combustion chamber pressure is less than or equal to 80 kPa, ignition is considered to have failed; otherwise, ignition is considered to have succeeded. If the outlet oil temperature rise rate is less than or equal to 5℃ / s, the ignition is considered to have failed; otherwise, the ignition is considered to have succeeded. The rate of temperature rise of the outlet oil is obtained by the detection equipment.

7. The multi-parameter correlation ramjet engine fault diagnosis system as described in claim 6, characterized in that, After determining that the number of ignition failures is greater than or equal to 2, the final ignition failure is determined, and it is determined whether the conditions for secondary ignition are met. Based on the conditions for secondary ignition, the timing for secondary ignition of the backup igniter is selected. Determining whether secondary ignition conditions are met, and selecting the secondary ignition timing for the backup igniter based on these conditions, includes: Condition 1: If the measured value of the pre-spray pressure is greater than or equal to 80% of the theoretical value of the pre-spray pressure, the backup igniter will be directly triggered for secondary ignition. Condition 2: If the measured fuel flow rate is greater than or equal to 80% of the theoretical fuel flow rate, the backup igniter will be directly triggered for secondary ignition. If conditions one and two are not met, wait for 2 seconds and trigger the backup igniter for secondary ignition.

8. The multi-parameter correlation ramjet engine fault diagnosis system as described in claim 2, characterized in that, The over-temperature / over-pressure judgment model includes a theoretical threshold calculation model for outlet oil pressure and a theoretical threshold calculation model for post-pump pressure; The theoretical threshold calculation model for outlet oil pressure is as follows: ； in, This is the theoretical value of fuel flow. , These are the fitting coefficients. The theoretical threshold temperature for the outlet oil is denoted as , which is a given constant. The nozzle area is... This represents the theoretical threshold value for the outlet oil pressure. The theoretical threshold calculation model for pump post-pressure is as follows: ； in, P b0 This is the theoretical threshold value for the pump's post-pump pressure. This is the theoretical threshold value for the outlet oil pressure. The friction loss along the pipeline can be calculated using a pipeline friction loss calculation model.

9. The multi-parameter correlation ramjet engine fault diagnosis system as described in claim 8, characterized in that, The over-temperature / over-pressure protection module performs correlation analysis, including When the measured value of the outlet oil temperature is greater than or equal to the theoretical threshold of the outlet oil temperature, it is judged as over-temperature / over-pressure; otherwise, it is judged as structurally safe. When the measured value of the outlet oil pressure is greater than or equal to the theoretical threshold of the outlet oil pressure, it is determined to be over-temperature / over-pressure; otherwise, it is determined to be structurally safe. When the measured value of the pump post-pressure is greater than or equal to the theoretical threshold of the pump post-pressure, it is judged as over-temperature / over-pressure; otherwise, it is judged as structurally safe. If the number of over-temperature / over-pressure events is greater than or equal to 2, then the over-temperature / over-pressure event is finally determined, the fuel flow is increased, and the backup hot oil valve is opened.

10. A multi-parameter correlation method for ramjet engine fault diagnosis, characterized in that, Engine fault diagnosis is performed using the multi-parameter correlation ramjet engine fault diagnosis system as described in any one of claims 1-9.

Images