High-reliability ignition device and reliability evaluation method thereof

Abstract

This invention provides a highly reliable ignition device and its reliability assessment method, relating to the field of igniter technology. The device includes: a main body and an outer nut; one side of the main body is fitted inside the outer nut, and a socket is provided on the side fitted inside the outer nut; an open cavity is provided within the main body; the open cavity, from the opening position inwards, sequentially comprises a diaphragm, a perlite-filled area, an ignition tube seat, a propellant housing, and an insulating material-filled area; two ignition tubes are symmetrically embedded in the ignition tube seat; the ignition tubes are connected to a head lead, which is connected to a tail lead located in the insulating material-filled area; the tail lead is connected to the socket. This invention innovatively introduces dual ignition tube redundancy in its structure. On the one hand, igniting the ignition tube is easier than directly igniting the propellant; on the other hand, the redundancy design can improve reliability. During reliability assessment, the complex ignition and starting process is decomposed into three independent stages with clear physical meaning, ensuring the accuracy of the assessment.

Description

Technical Field

[0001] This invention relates to the field of ignition technology, and in particular to a highly reliable ignition device and its reliability assessment method. Background Technology

[0002] Igniters can be classified according to their application into: gas appliance igniters, automotive engine igniters, industrial burner igniters, and aerospace igniters. Among them, aerospace igniters require extremely high reliability and can be further divided into gunpowder igniters and starting igniters.

[0003] like Figure 1 The diagram shows a traditional igniter. The working principle of a traditional igniter is simple: electricity is passed through a wire, causing the wire to heat up. An electric igniter is located at the end of the wire. As the current flows, the temperature rises, reaching the ignition point of the gunpowder, thus igniting it.

[0004] Traditional igniters have the following problems: 1. They lack redundancy; if a wire breaks, the entire system fails to function. 2. They have high requirements for the propellant, requiring a low ignition point. Furthermore, current igniter evaluations typically involve extensive testing, resulting in significant evaluation costs. Summary of the Invention

[0005] One of the objectives of this invention is to provide a highly reliable ignition device and a reliability evaluation method thereof to solve the aforementioned technical problems.

[0006] This invention provides a high-reliability ignition device, comprising: a main body and an outer nut; a socket is provided on one side of the main body, which is fitted inside the outer nut; an opening is provided inside the main body; the opening is provided with a diaphragm, a perlite filling area, an ignition tube seat, a propellant housing, and an insulating filling area in sequence from the opening position inward; two ignition tubes are symmetrically embedded in the ignition tube seat; the ignition tubes are connected to a head lead, which is connected to a tail lead provided in the insulating filling area; the tail lead is connected to the socket.

[0007] Preferably, a graphite sealing ring is provided between the body and the outer nut.

[0008] Preferably, the ignition tube is in contact with the propellant casing.

[0009] Preferably, the ignition tube includes: two electrodes, a protective resistor, gunpowder inside the ignition tube, and an ignition tube housing; the electrodes are electrically connected to the head lead; the protective resistor is disposed between the two electrodes; the gunpowder inside the ignition tube housing is disposed within the gunpowder inside the ignition tube; and the ends of the electrodes are disposed within the gunpowder inside the ignition tube.

[0010] The present invention also provides a reliability assessment method, applied to any of the above-mentioned high-reliability ignition devices, comprising: Step S1: Perform a reliability analysis on the ignition tube process to obtain the first reliability data; Step S2: Perform a reliability analysis on the ignition process of the main charge to obtain second reliability data; Step S3: Perform a reliability analysis on the engine starting process to obtain third reliability data; Step S4: Combine the first reliability data, the second reliability data, and the third reliability data to determine the overall reliability.

[0011] Preferably, step S1: perform a reliability analysis on the ignition tube process to obtain first reliability data, including: Determine the reliability of a single tube based on the minimum total ignition current; Based on the single-tube reliability, the dual-tube redundancy reliability is determined.

[0012] Preferably, step S2: performing a reliability analysis on the ignition process of the main charge to obtain second reliability data, including: Analytical samples were selected from ignition delay event data; Perform chi-square normality verification on the analyzed samples to verify that they follow a normal distribution; When the verification is successful, the maximum ignition delay time threshold is obtained, and the probability of the charge being distributed within the maximum ignition delay time threshold is calculated as the reliability of the ignition process of the main charge.

[0013] Preferably, step S3: perform a reliability analysis on the engine starting process to obtain third reliability data, including: Samples of the engine thrust chamber pressure build-up time were obtained, and their normal distribution was confirmed through testing. This distribution is denoted as random variable r ~ N(μr,σr²). Samples of intense combustion time of the igniter were obtained and confirmed to follow a normal distribution through testing, denoted as random variable s~N(μs,σs²); Establish a time-series interference model: Define the time difference variable ζ = r – s; define reliability failure as pressure build-up time being longer than combustion time, i.e., P (ζ ≥ 0); According to probability theory theorems, ζ also follows a normal distribution, with its expected value and standard deviation being: μζ=μr-μs σζ=√(σr²+σs²) P(ζ≥0) is transformed into a standard normal distribution and solved to obtain the probability that no failure has occurred, which is used as the reliability of the engine starting process.

[0014] Preferably, step S4: combining the first reliability data, the second reliability data, and the third reliability data to determine the overall reliability, including: The total reliability is the product of the dual-tube redundancy reliability, the reliability of the main charge ignition process, and the reliability of the engine start-up process.

[0015] The beneficial effects of this invention are as follows: Structurally, a dual-ignition tube redundancy was innovatively introduced. On the one hand, igniting the ignition tube is easier than directly igniting the propellant; on the other hand, the redundancy design can be used to improve reliability. During reliability assessment, the complex ignition and initiation process was broken down into three independent stages with clear physical meaning, ensuring the accuracy of the assessment. This allows designers to accurately identify whether potential risks are caused by insufficient ignition electrical signal, moisture-induced delays in the main charge, or mismatches in pressure build-up timing, greatly optimizing the direction of subsequent iterative design.

[0016] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 A schematic diagram of a traditional igniter; Figure 2 This is a schematic diagram of a high-reliability ignition device according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the ignition tube in an embodiment of the present invention; Figure 4 This is a schematic diagram of a reliability assessment method according to an embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the specific process of a reliability assessment method in an embodiment of the present invention. Detailed Implementation

[0019] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0020] This invention provides a highly reliable ignition device, such as... Figure 2 As shown, it includes: The main body 1 and the outer nut 2 are provided. One side of the main body 1 is fitted inside the outer nut 2, and a socket 16 is provided on the side fitted inside the outer nut 2. An open mouth is provided inside the main body 1. The open mouth is provided with a diaphragm 11, a perlite filling area 12, an ignition tube seat 13, a charge housing 14, and an insulating filling area 15 in sequence from the opening position inward. Two ignition tubes 17 are symmetrically embedded in the ignition tube seat 13. The ignition tubes 17 are connected to a head lead 19, and the head lead 19 is connected to a tail lead 18 provided in the insulating filling area 15. The tail lead 18 is connected to the socket 16.

[0021] A graphite sealing ring 3 is provided between the main body 1 and the outer nut 2.

[0022] The ignition tube 17 is in contact with the propellant casing 14.

[0023] Among them, such as Figure 3 As shown, the ignition tube 17 includes: two electrodes 21, a protective resistor 22, gunpowder 23 inside the ignition tube, and an ignition tube housing 24. The electrodes 21 are electrically connected to the head lead 19; the protective resistor 22 is positioned between the two electrodes 21; the gunpowder 23 inside the ignition tube housing 24 is disposed; the ends of the electrodes 21 are located inside the gunpowder 23. The working process of the ignition tube is as follows: current flows into the electrodes from the wire, and a protective resistor is placed between the two electrodes, with a short circuit outside the resistor. After the current from the outside flows in, a large amount of heat is generated due to the short circuit between the two electrodes. This heat ignites the gunpowder inside the ignition tube (usually lead stefanate, etc.), producing a relatively high-pressure gas. The ignition tube housing is made of aluminum. When the gas temperature reaches a certain level, the aluminum melts automatically, and a flame is ejected, igniting the main charge behind it. The protective resistor prevents accidental detonation caused by small inputs such as static electricity. The reason for using aluminum for the ignition tube housing is that aluminum is easily melted. When the flame temperature is low, the ignition tube is a closed-loop cavity, which is a constant-volume heating process in thermodynamics. When the temperature is higher, the aluminum melts, and the flame is ejected. Using aluminum ensures that the flame ejected from the ignition tube has a high temperature. Furthermore, it can be ejected directly without external operation. This invention addresses the lack of redundancy in traditional igniters. The working process is as follows: Electricity is applied to the wire, and the current flows through the wire to the ignition tube. The ignition tube ignites, and a flame is emitted from it, igniting the gunpowder. Two ignition tubes are provided for redundancy; the wire does not directly ignite the gunpowder, but an additional ignition tube is added between the gunpowder and the wire. This is similar to lighting a match before igniting charcoal, using the burning match to ignite the charcoal. Furthermore, redundancy is added. This invention also provides a reliability assessment method applicable to any of the aforementioned high-reliability ignition devices, such as... Figure 4 As shown, it includes: Step S1: Perform a reliability analysis on the ignition tube process to obtain the first reliability data; Step S2: Perform a reliability analysis on the ignition process of the main charge to obtain second reliability data; Step S3: Perform a reliability analysis on the engine starting process to obtain third reliability data; Step S4: Combine the first reliability data, the second reliability data, and the third reliability data to determine the overall reliability.

[0024] In one embodiment, step S1: performing a reliability analysis on the ignition tube process to obtain first reliability data, including: Determine the reliability of a single tube based on the minimum total ignition current; Based on the single-tube reliability, the dual-tube redundancy reliability is determined.

[0025] The minimum total ignition current of a single ignition tube under specific confidence and reliability requirements is calculated using a rise-fall method test. After confirming that the actual operating current is greater than this threshold, the single-tube ignition reliability R1 and R2 are obtained. Based on the redundant design of the dual ignition tubes, the reliability R_I of this process is calculated: R_I = 1 - (1 - R1)(1 - R2).

[0026] In one embodiment, step S2: performing a reliability analysis on the ignition process of the main charge to obtain second reliability data includes: Analytical samples were selected from ignition delay event data; Perform chi-square normality verification on the analyzed samples to verify that they follow a normal distribution; When the verification is successful, the maximum ignition delay time threshold is obtained, and the probability of the charge being distributed within the maximum ignition delay time threshold is calculated as the reliability of the ignition process of the main charge.

[0027] In other words, the time it takes for the main charge to ignite and break through the diaphragm to produce a flame is defined as the "ignition delay time". Ignition delay time data from multiple batches of products under extreme conditions (high temperature, low temperature, temperature cycling, drop) were extracted, and the group with the largest standard deviation was selected as the worst-case sample. A chi-square (χ²) normality test was performed on the sample to verify that it follows a normal distribution N(μ1,σ1²). Based on the maximum ignition delay time threshold specified in the technical specifications, the probability of the distribution falling within this threshold was calculated and used as the reliability R_II of the process.

[0028] In one embodiment, step S3: performing a reliability analysis on the engine starting process to obtain third reliability data, including: Samples of the engine thrust chamber pressure build-up time were obtained, and their normal distribution was confirmed through testing. This data is denoted as a random variable. ; Samples of the intense combustion time of the igniter were obtained and confirmed to follow a normal distribution through testing; this is denoted as a random variable. ; Establish a time-series interference model: Define the time difference variable ζ = r – s; define reliability failure as pressure build-up time being longer than combustion time, i.e., P (ζ ≥ 0); According to probability theory theorems, ζ also follows a normal distribution, with its expected value and standard deviation being: μζ=μr-μs σζ=√(σr²+σs²) P(ζ≥0) is transformed into a standard normal distribution and solved to obtain the probability that no failure has occurred, which is used as the reliability of the engine starting process, R_III.

[0029] That is, in this embodiment, the engine's "pressure build-up time" is regarded as the stress faced by the system, and the igniter's "intense combustion time" is regarded as the system's resistance (strength).

[0030] Step S4: Combining the first reliability data, the second reliability data, and the third reliability data to determine the overall reliability, including: The total reliability is the product of the dual-tube redundancy reliability, the reliability of the main charge ignition process, and the reliability of the engine start-up process. That is, the total reliability R_total = R_I × R_II × R_III. Furthermore, Figure 5 A schematic diagram of the specific process for reliability assessment is provided.

[0031] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A high-reliability ignition device, characterized in that, include: Main body and outer nut; The main body is fitted into the outer nut on one side, and a socket is provided on the side fitted into the outer nut; an open mouth is provided inside the main body; from the opening position inward, the open mouth is provided with a diaphragm, a perlite filling area, an ignition tube seat, a charge housing, and an insulating filling area in sequence; two ignition tubes are symmetrically embedded in the ignition tube seat; the ignition tubes are connected to a head lead, and the head lead is connected to a tail lead provided in the insulating filling area; the tail lead is connected to the socket.

2. The high-reliability ignition device as described in claim 1, characterized in that, A graphite sealing ring is provided between the body and the outer nut.

3. The high-reliability ignition device as described in claim 1, characterized in that, The ignition tube is in contact with the propellant casing.

4. The high-reliability ignition device as described in claim 1, characterized in that, The ignition tube includes: two electrodes, a protective resistor, gunpowder inside the ignition tube, and an ignition tube housing; the electrodes are electrically connected to the head lead; the protective resistor is positioned between the two electrodes; the gunpowder inside the ignition tube housing is disposed within the gunpowder inside the ignition tube; the ends of the electrodes are positioned within the gunpowder inside the ignition tube.

5. A reliability assessment method, applied to the high-reliability ignition device as described in any one of claims 1 to 4, characterized in that, include: Step S1: Perform a reliability analysis on the ignition tube process to obtain the first reliability data; Step S2: Perform a reliability analysis on the ignition process of the main charge to obtain second reliability data; Step S3: Perform a reliability analysis on the engine starting process to obtain third reliability data; Step S4: Combine the first reliability data, the second reliability data, and the third reliability data to determine the overall reliability.

6. The reliability assessment method as described in claim 5, characterized in that, Step S1: Perform a reliability analysis on the ignition tube process to obtain the first reliability data, including: Determine the reliability of a single tube based on the minimum total ignition current; Based on the single-tube reliability, the dual-tube redundancy reliability is determined.

7. The reliability assessment method as described in claim 6, characterized in that, Step S2: Perform a reliability analysis on the ignition process of the main charge to obtain second reliability data, including: Analytical samples were selected from ignition delay event data; Perform chi-square normality verification on the analyzed samples to verify that they follow a normal distribution; When the verification is successful, the maximum ignition delay time threshold is obtained, and the probability of the charge being distributed within the maximum ignition delay time threshold is calculated as the reliability of the ignition process of the main charge.

8. The reliability assessment method as described in claim 7, characterized in that, Step S3: Perform a reliability analysis on the engine starting process to obtain third-party reliability data, including: Samples of the engine thrust chamber pressure build-up time were obtained, and their normal distribution was confirmed by testing. This distribution is denoted as random variable r ~ N(μr,σr²). Samples of intense combustion time of the igniter were obtained and confirmed to follow a normal distribution through testing, denoted as random variable s~N(μs,σs²); Establish a time-series interference model: Define the time difference variable ζ = r – s; define reliability failure as pressure build-up time being longer than combustion time, i.e., P (ζ ≥ 0); According to probability theory theorems, ζ also follows a normal distribution, with its expected value and standard deviation being: μζ=μr-μs σζ=√(σr²+σs²) P(ζ≥0) is transformed into a standard normal distribution and solved to obtain the probability that no failure has occurred, which is used as the reliability of the engine starting process.

9. The reliability assessment method as described in claim 8, characterized in that, Step S4: Combine the first reliability data, the second reliability data, and the third reliability data to determine the overall reliability, including: The total reliability is the product of the dual-tube redundancy reliability, the reliability of the main charge ignition process, and the reliability of the engine start-up process.

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