Method for testing flame retardance of automobile wire harness
By dividing automotive wiring harnesses into conventional and oil-contaminated groups, constructing heat source analysis groups and analyzing heat source diffusion diagrams, the test deviation caused by oil contamination in existing technologies is resolved, and accurate flame retardancy evaluation is achieved.
Patent Information
- Application Number
- CN202511177831.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-21
- Publication Date
- 2025-10-10
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Existing automotive wiring harness flame retardancy testing technology cannot accurately consider the impact of oil contamination on the wiring harness after use, resulting in deviations in test results and difficulty in applying to wiring harnesses of different materials.
The wiring harnesses were divided into conventional experimental groups and oil pollution experimental groups, and a heat source analysis group was constructed. The heat source diffusion map was captured and analyzed using a thermal imaging device, and a flame retardant data analysis model was established to accurately judge the flame retardancy of the wiring harnesses.
The accuracy and effectiveness of flame retardancy testing of automotive wiring harnesses have been improved, and the burning length and time can be accurately determined. The problem of oil adhesion has been taken into consideration, and the influence of open flame heat sources on the test has been avoided.
Smart Images
Figure CN120761571A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of automobile wiring harness flame retardancy testing, in particular to a method for testing automobile wiring harness flame retardancy. Background Art
[0002] Automotive wiring harness flame retardancy testing technology refers to an experimental method that quantitatively evaluates the wiring harness material's resistance to combustion, flame spread rate, and morphological stability under the action of flames, high temperatures, or radiant heat sources by simulating vehicle fire scenarios. Its core goal is to ensure that the wiring harness can extinguish itself and suppress the spread of fire in the event of a short circuit, overload, or combustion caused by an external fire source, thereby maintaining structural integrity.
[0003] Existing automotive wiring harness flame retardancy testing technology is usually tested according to conventional wiring harness flame retardancy testing methods, without taking into account the particularity of automotive wiring harnesses. After years of use, automotive wiring harnesses are very likely to adhere to oil stains, which will greatly affect the flame retardancy of automotive wiring harnesses. Therefore, the traditional wiring harness flame retardancy testing method is not accurate for the test results of automotive wiring harnesses. The flame retardancy test data includes the anti-burning time, self-extinguishing time and burning length. The fundamental purpose is to study whether the automotive wiring harness is burning and extract the burning length. The existing automotive wiring harness flame retardancy testing technology usually uses manual identification to determine whether the automotive wiring harness is burning, or uses machine identification. However, when using machine identification, it only determines whether the automotive wiring harness is burning and extracts the burning length by setting a temperature threshold. This method is not only difficult to distinguish between the heat source and the burning of the automotive wiring harness, but also cannot be applied to automotive wiring harnesses of different materials. The reason is that different materials have different ignition points. The existing automotive wiring harness flame retardancy testing technology also has the problem of inaccurate extraction of flame retardancy test data, resulting in deviations in the test results of the flame retardancy test. Summary of the Invention
[0004] The present invention aims to solve one of the technical problems in the prior art to at least a certain extent, by dividing the automotive wiring harness into a conventional experimental group and an oil pollution experimental group, and constructing a heat source analysis group at the same time, then igniting the combustible material and taking a heat source diffusion analysis diagram, and then analyzing the heat source diffusion analysis diagram to obtain the heat source heat diffusion relationship, and performing flame retardancy tests on the conventional experimental group and the oil pollution experimental group respectively, photographing the automotive wiring harness through a thermal imaging device to obtain a test image, and then constructing a flame retardant data analysis model, defining an analysis process for precise flame retardant data, and then analyzing the conventional test diagram and the oil pollution test diagram through the flame retardant data analysis model to obtain precise conventional flame retardant data and precise oil pollution flame retardant data respectively, and finally performing flame retardancy analysis on the precise flame retardant data to evaluate whether the flame retardancy of the automotive wiring harness is qualified, so as to solve the problem that the existing automotive wiring harness flame retardancy testing technology still has the problem that the extraction of flame retardancy test data is not accurate enough, resulting in deviations in the test results of the flame retardancy test.
[0005] To achieve the above objectives, the present application provides a method for testing the flame retardancy of automotive wiring harnesses, comprising the following steps: The automotive wiring harnesses were divided into two flame retardant test groups, including a conventional test group and an oil pollution test group, and a heat source analysis group was constructed at the same time; Analyze the heat source heat diffusion relationship through the heat source analysis group; The flame retardancy tests were conducted on the conventional experimental group and the oil pollution experimental group respectively. The automotive wiring harness was photographed using a thermal imaging device to obtain test images. Analyze the test image based on the heat source heat diffusion relationship to obtain accurate flame retardant data of automotive wiring harnesses; Conduct flame retardancy analysis on precise flame retardant data to evaluate whether the flame retardancy of automotive wiring harnesses is qualified.
[0006] Furthermore, the automotive wiring harness is divided into two flame retardant test groups, which include a conventional test group and an oil pollution test group. At the same time, constructing a heat source analysis group includes the following sub-steps: The automotive wiring harnesses were divided into two flame retardant test groups: conventional test group and oil pollution test group; The automotive wiring harness in the conventional experimental group is named conventional wiring harness, and the automotive wiring harness in the oily experimental group is named oily wiring harness. The conventional wiring harness and the oily wiring harness are exactly the same. Soak the oily wiring harness in the engine oil for a short time and then dry it, repeating the first time; A heat source analysis group is constructed, wherein different types of combustibles are arranged in the heat source analysis group, and the combustibles have a fixed form.
[0007] Furthermore, analyzing the heat source heat diffusion relationship through the heat source analysis group includes the following sub-steps: Ignite the combustible material and take a heat source diffusion analysis diagram; The heat source diffusion analysis diagram is analyzed to obtain the heat source heat diffusion relationship.
[0008] Furthermore, igniting the combustible material and photographing the heat source diffusion analysis diagram includes the following sub-steps: Ignite the combustible material and ensure that all surfaces of the combustible material are in a burning state; Use thermal imaging devices to photograph combustibles in a burning state and obtain a heat source diffusion analysis diagram; Extract the outline of the combustibles in the heat source diffusion analysis diagram to obtain the object outline; The heat source diffusion analysis map is converted into a grayscale map, named as a heat source grayscale map, the pixel points within the object outline in the heat source grayscale map are named as heat source points, and the pixel points outside the object outline in the heat source grayscale map are named as diffusion points; A first number of heat source points are randomly selected and named as reference points. The diffusion points closest to the reference points are found and named as direction points. Different reference points correspond to different direction points.
[0009] Furthermore, analyzing the heat source diffusion analysis diagram to obtain the heat source heat diffusion relationship includes the following sub-steps: Analyze any reference point, construct a ray with the reference point as the endpoint and the direction point as the direction, and name it the diffusion auxiliary line. Name the pixel points on the diffusion auxiliary line as the points to be analyzed. Starting from the endpoint of the diffusion auxiliary line, the points to be analyzed are numbered along the direction of the diffusion auxiliary line, and the symbol P is used. n Indicates that n is a non-zero natural number and n is the sequence number of P; Extraction of P n Gray value, marked as H n , with serial number n as X axis, H n Establish a two-dimensional coordinate system for the Y axis, named heat source heat diffusion diagram, and set H n Enter the heat source heat diffusion diagram according to n, and name the coordinate points in the heat source heat diffusion diagram as heat source heat diffusion coordinates; Connect the heat diffusion coordinates of two adjacent heat sources with a straight line to obtain a change trend line, and obtain the slope of the change trend line, which is named the heat change trend; Obtain two pixel points corresponding to the intersection of the heat source point and the diffusion point in the diffusion auxiliary line, name the diffusion point as the unburned point, and name the heat source point as the end point; Obtain the heat change trend between the termination point and the unburned point, name it the combustion termination trend, mark it as TCT, and number the heat change trends before TCT in order from front to back, using the symbol RF i Indicates that the heat change trend after TCT is numbered, and the symbol RA j Indicates that both i and j are non-zero natural numbers, i is the serial number of RF, and j is the serial number of RA; For each value of i, calculate |RF i / RF i+1 |, mark the result as GF i , the GF i There is no GF in max(i) , the max() is the maximum value operator, and then calculate |RF max(i) / TFT|, mark the calculation result as GT; Analyze and calculate the GF of all reference points of all combustibles i As well as GT, statistical GF iThe range of and GT are named heat source floating range and boundary floating range respectively. The average value of the minimum value of the heat source floating range and the maximum value of the boundary floating range are calculated to obtain the preliminary judgment threshold of the boundary. For each value of j, calculate RA j / TFT, mark the calculation result as GA j , with j as the horizontal axis, GA j Establish a two-dimensional coordinate system for the vertical axis, named as the secondary decision analysis diagram, and use GA j Enter j into the secondary determination analysis chart, perform linear regression analysis on the secondary determination analysis chart, obtain the slope of the regression function, and name it the slope change trend. Analyze and count the range of the slope change trend of all reference points of all combustibles to obtain the secondary determination range. The preliminary determination threshold and the secondary determination range together constitute the heat source heat diffusion relationship.
[0010] Furthermore, flame retardancy tests were performed on the conventional experimental group and the oil pollution experimental group respectively. The automotive wiring harness was photographed by a thermal imaging device to obtain the test images, which included the following sub-steps: Randomly select a point on the car wiring harness as a test point, irradiate the test point with thermal radiation, and ensure that the thermal radiation is focused on the test point during irradiation; A conventional test image is obtained by photographing a conventional wiring harness with a thermal imaging device, and an oily wiring harness is photographed with a thermal imaging device to obtain an oily test image. The conventional test image and the oily test image are test images.
[0011] Furthermore, the test image is analyzed based on the heat source and heat diffusion relationship to obtain accurate flame retardant data of the automotive wiring harness, which includes the following sub-steps: Build a flame retardant data analysis model and define the analysis process for accurate flame retardant data; The conventional test chart and the oil stain test chart are analyzed by the flame retardant data analysis model to obtain accurate conventional flame retardant data and accurate oil stain flame retardant data respectively.
[0012] Furthermore, a flame retardant data analysis model is constructed to define the analysis process of accurate flame retardant data, which includes the following sub-steps: Construct a flame retardant data analysis model. When analyzing any test image, name it as the image to be analyzed; Based on the analysis process of the preliminary judgment threshold and the secondary judgment range, the geometric center of the test point is used as the reference point, and diffusion auxiliary lines are drawn directly above, directly below, directly to the left, and directly to the right of the reference point. The reference point of the image to be analyzed and the diffusion auxiliary lines are named reference analysis point and diffusion analysis line respectively. The diffusion analysis lines corresponding to the top, bottom, left, and right are named as the top line, bottom line, left line, and right line respectively; When analyzing any one of the upper line, lower line, left line, and right line, it is named as the line to be analyzed. Any pixel point on the line to be analyzed is assumed to be the end point and the corresponding heat source floating range and boundary floating range are analyzed, which are named the first floating range and the second floating range respectively. Determine whether the minimum value of the first floating range is greater than the preliminary determination threshold while the maximum value of the second floating range is less than the preliminary determination threshold. If so, output a preliminary verification pass signal; otherwise, output a preliminary verification fail signal. If the output is a preliminary verification pass signal, the corresponding slope change trend is analyzed and named as the trend to be analyzed. It is determined whether the trend to be analyzed is within the secondary judgment range. If so, a burned signal is output; if not, an unburned signal is output; While radiating heat to the test point, start the timer. When the burn signal is output, record the timer time, which is named as the anti-burning time. Then stop the heat radiation and reset the timer. Check whether the burn signal is output. If so, continue to count. If not, record the timer time, which is named as the self-extinguishing time. If a burned signal is output when any pixel point is assumed to be the end point for analysis, the corresponding pixel point is marked as the burning end point. All the burning end points are counted, and the burning end point farthest from the reference analysis point is obtained and named the length reference point. The distance between the length reference point and the reference analysis point is obtained and named the burning length. The anti-burning time, self-extinguishing time and burning length are precise flame retardant data.
[0013] Furthermore, the conventional test image and the oil stain test image are analyzed by the flame retardant data analysis model to obtain accurate conventional flame retardant data and accurate oil stain flame retardant data, respectively, including the following sub-steps: Analyze conventional test images through the flame retardant data analysis model to obtain accurate conventional flame retardant data, including conventional anti-burning time, conventional self-extinguishing time and conventional burning length; The oil stain test image is analyzed through the flame retardant data analysis model to obtain accurate oil stain flame retardant data, including the oil stain anti-burning time, oil stain self-extinguishing time and oil stain burning length.
[0014] Furthermore, flame retardancy analysis is performed on the precise flame retardancy data to evaluate whether the flame retardancy of the automotive wiring harness is qualified, which includes the following sub-steps: Determine whether the conventional anti-burning time, conventional self-extinguishing time, conventional burning length, oil pollution anti-burning time, oil pollution self-extinguishing time and oil pollution burning length meet the safety standards. If all meet the safety standards, output a flame retardant qualified signal; otherwise, output a flame retardant unqualified signal; If a flame retardant qualified signal is output, the flame retardancy of the automobile wiring harness is marked as qualified; if a flame retardant unqualified signal is output, the flame retardancy of the automobile wiring harness is marked as unqualified.
[0015] Beneficial effects of the present invention: The present invention divides the automobile wiring harness into a conventional experimental group and an oil pollution experimental group, and at the same time constructs a heat source analysis group. Then, the combustible material is ignited and a heat source diffusion analysis diagram is photographed. The heat source diffusion analysis diagram is then analyzed to obtain a heat source heat diffusion relationship. The advantage is that if an object burns, its heat will diffuse to the surroundings, and the heat will gradually decrease during the diffusion. This results in a certain relationship between the heat source and the temperature of its surroundings in the infrared thermal imaging diagram, namely, the heat source heat diffusion relationship. By analyzing the heat source heat diffusion relationship, it is possible to accurately determine whether the object is burning, and at the same time, the most accurate burning point of the object can be found, thereby determining the most accurate burning length of the automobile wiring harness, thereby improving the accuracy and effectiveness of the automobile wiring harness flame retardancy test.
[0016] The present invention performs flame retardancy tests on a conventional experimental group and an oil stain experimental group respectively, photographs the automobile wiring harness through a thermal imaging device to obtain a test image, then constructs a flame retardant data analysis model, defines an analysis process for precise flame retardant data, and then analyzes the conventional test image and the oil stain test image through the flame retardant data analysis model to obtain precise conventional flame retardant data and precise oil stain flame retardant data, respectively. Finally, a flame retardancy analysis is performed on the precise flame retardant data to evaluate whether the flame retardancy of the automobile wiring harness is qualified. The advantage is that when the flame retardancy test is performed on the conventional experimental group and the oil stain experimental group, the heat source is replaced by thermal radiation from the traditional open flame. The open flame will radiate heat to the surroundings, thereby affecting the judgment of whether the automobile wiring harness is burning, while the thermal radiation will not radiate heat to the surroundings, thereby not affecting the judgment of the flame retardant data analysis model. In addition, the oil stain adhesion problem of the automobile wiring harness is taken into consideration during the test, thereby improving the accuracy and rationality of the flame retardancy test of the automobile wiring harness. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 is a flow chart of the steps of the method of the present invention; Figure 2 A schematic diagram of the object outline of the present invention; Figure 3 is a schematic diagram of a heat source grayscale image of the present invention; Figure 4 Schematic diagram of the distribution of heat source points and diffusion points of the present invention; Figure 5 is a schematic diagram of a diffusion auxiliary line of the present invention; Figure 6 Schematic diagram of the heat source heat diffusion diagram of the present invention; Figure 7 Schematic diagram of the secondary determination analysis diagram of the present invention; Figure 8 A schematic diagram of reference points and diffusion auxiliary lines of the present invention; Figure 9 Schematic diagram of the hypothetical end point of the present invention. DETAILED DESCRIPTION
[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0019] Example 1, please refer to Figure 1 As shown, the present application provides a method for testing the flame retardancy of an automotive wiring harness, comprising the following steps: Step S1, dividing the automotive wiring harness into two flame retardant test groups, the flame retardant test group including a conventional test group and an oil pollution test group, and constructing a heat source analysis group at the same time; Step S1 includes the following sub-steps: Step S101, dividing the automobile wiring harness into two flame retardant test groups, namely a conventional test group and an oil pollution test group; Step S102, the automotive wiring harness in the conventional experimental group is named as a conventional wiring harness, and the automotive wiring harness in the oil pollution experimental group is named as an oil pollution wiring harness, and the conventional wiring harness and the oil pollution wiring harness are exactly the same; Step S103, soaking the oily wiring harness in engine oil for a first time and then drying it, and repeating the first time; Step S104: constructing a heat source analysis group, wherein the heat source analysis group is provided with different types of combustibles, and the combustibles have a fixed form; In a specific implementation, soaking the oily wiring harness in engine oil for a first time and then drying it is actually to simulate the situation where the surface of the automotive wiring harness is adhered to oil after years of use. The first time number is not fixed, and it is only necessary to ensure that the surface of the automotive wiring harness is adhered to oil. Combustibles refer to objects that will not deform in a short period of time when they burn themselves. This is to make a more accurate distinction between combustibles and surrounding air. For example, charcoal has a very stable shape when burned in a short period of time. In this embodiment, commercial charcoal products are selected as combustibles for analysis. Commercial charcoal products have a more regular appearance, which is convenient for analysis in this embodiment.
[0020] Step S2, analyzing the heat source heat diffusion relationship by the heat source analysis group; Step S2 includes the following sub-steps: Step S201, ignite the combustible material and take a heat source diffusion analysis diagram; Step S201 includes the following sub-steps: Step S201.1, ignite the combustible material to ensure that all surfaces of the combustible material are in a burning state; Step S201.2, photographing the combustible material in a burning state using a thermal imaging device to obtain a heat source diffusion analysis diagram; See also Figure 2 As shown, in step S201.3, contour extraction is performed on the combustible object in the heat source diffusion analysis diagram to obtain the object contour; See also Figures 3 and 4 As shown, step S201.4, converting the heat source diffusion analysis map into a grayscale map, naming it a heat source grayscale map, naming the pixel points within the object outline in the heat source grayscale map as heat source points, and naming the pixel points outside the object outline in the heat source grayscale map as diffusion points; Step S201.5: randomly select a first number of heat source points, name them reference points, and search for diffusion points closest to the reference points, name them direction points. Different reference points correspond to different direction points. In the specific implementation, a heat source diffusion analysis diagram is obtained by shooting and the object contour is extracted. Figure 2 As shown, the heat source grayscale image is converted as Figure 3 As shown in the figure, the distribution of heat source points and diffusion points is as follows: Figure 4 As shown, white pixels represent heat source points, black pixels represent diffusion points, and the first number is set by the tester without special requirements. In this embodiment, the first number is set to 5, that is, 5 heat source points are extracted as reference points. The purpose of searching for direction points is to reduce the number of pixels that need to be analyzed to increase the analysis rate. In fact, other directions can also be analyzed. Figure 2 It can be seen that heat diffusion has a certain range. Through a large number of experiments, it is found that heat diffusion is most obvious within a range of 5 cm. Therefore, when obtaining diffusion points, only diffusion points within 5 cm from the heat source point are obtained. 5 cm corresponds to 30 pixels in the pixel length in this embodiment, that is, only diffusion points within 30 pixels from the heat source point are obtained, one pixel length corresponds to one pixel point, and diffusion points exceeding 30 pixels in length are not included in the reference range.
[0021] Step S202, analyzing the heat source diffusion analysis diagram to obtain the heat source heat diffusion relationship; Step S202 includes the following sub-steps: See also Figure 5As shown, in step S202.1, any reference point is analyzed, and a ray is constructed with the reference point as the endpoint and the direction point as the direction, which is named as the diffusion auxiliary line. The pixel points on the diffusion auxiliary line are named as the points to be analyzed. Starting from the endpoint of the diffusion auxiliary line, the points to be analyzed are numbered along the direction of the diffusion auxiliary line, and the symbol P is used. n Indicates that n is a non-zero natural number and n is the sequence number of P; See also Figure 6 As shown, step S202.2, extract P n Gray value, marked as H n , with serial number n as X axis, H n Establish a two-dimensional coordinate system for the Y axis, named heat source heat diffusion diagram, and set H n Enter the heat source heat diffusion diagram according to n, and name the coordinate points in the heat source heat diffusion diagram as heat source heat diffusion coordinates; Step S202.3: Connect the heat diffusion coordinates of two adjacent heat sources with a straight line to obtain a change trend line, and obtain the slope of the change trend line, which is named as the heat change trend; Step S202.4, obtaining two pixel points corresponding to the intersection of the heat source point and the diffusion point in the diffusion auxiliary line, naming the diffusion point as the unburned point, and naming the heat source point as the end point; Step S202.5, obtain the heat change trend between the end point and the unburned point, name it as the combustion end trend, mark it as TCT, and number the heat change trends before TCT in order from front to back, using the symbol RF i Indicates that the heat change trend after TCT is numbered, and the symbol RA j Indicates that i and j are both non-zero natural numbers and i is the serial number of RF, j is the serial number of RA; In the specific implementation, taking a certain reference point as an example, the diffusion auxiliary line is drawn as follows Figure 5 As shown, the black line segment is the diffusion auxiliary line, the white pixel points in the diffusion auxiliary line represent the end point, and the gray pixel points represent the unburned point. Figure 5 The left side of the diffusion auxiliary line is the diffusion point, the right side is the heat source point, and the rightmost point to be analyzed is the reference point. That is, each point to be analyzed is numbered in order from right to left to obtain P n , and obtain H n , 1≤n≤40, the heat source heat diffusion diagram is constructed as follows Figure 6 As shown, Figure 6 The heat diffusion coordinates of adjacent heat sources have been connected by straight lines. There are 39 trend lines in total, so 39 heat change trends have been obtained. Figure 6 The longest trend line in the chart corresponds to the heat change trend, which is TCT, and the number is RF.i and RA j , where 1≤i≤9, 1≤j≤30; Step S202.6: For each value of i, calculate |RF i / RF i+1 |, mark the result as GF i , GF i There is no GF in max(i) , max() is the maximum value operator, and then calculate |RF max(i) / TFT|, mark the calculation result as GT; Step S202.7: Analyze and count the GF of all reference points of all combustibles i As well as GT, statistical GF i The range of and GT are named heat source floating range and boundary floating range respectively. The average value of the minimum value of the heat source floating range and the maximum value of the boundary floating range are calculated to obtain the preliminary judgment threshold of the boundary. In the specific implementation, GF is calculated i This is because the heat source points have already burned, and the heat generated is relatively small, that is, the temperature between the heat source points fluctuates within a certain range, and the GF is calculated. i The fluctuation trend of heat between heat source points can be found. For example, if RF1 is -2 and RF2 is 3, the calculated GF1 is 0.6667. The calculation result is rounded to four decimal places. i The similarity of heat change trends between heat source points is revealed, and GT is the similarity between the heat change trend before TCT and TCT. For example, in this embodiment, RF max(i) is 2, TCT is -28, and the calculated GT is 0.0714. It can be seen that GT is much smaller than GF. i This is one of the characteristics of distinguishing the end point. By counting the heat source floating range and boundary floating range of all reference points of all combustibles, we can know the similarity of the heat change trends between the heat source points and the difference between the end point and the heat source point. The heat source floating range is [0.4, 1.6], and the boundary floating range is [0.0564, 0.0832]. Further calculation shows that the preliminary judgment threshold of the boundary is 0.2416. The calculation of the preliminary judgment threshold of the boundary is to leave a certain redundancy for the heat source floating range and the boundary floating range. See also Figure 7 As shown, in step S202.8, for each value of j, calculate RA j / TFT, mark the calculation result as GA j , with j as the horizontal axis, GA j Establish a two-dimensional coordinate system for the vertical axis, named as the secondary decision analysis diagram, and use GA jEnter j into the secondary determination analysis chart, perform linear regression analysis on the secondary determination analysis chart, obtain the slope of the regression function, and name it the slope change trend. Analyze and count the range of the slope change trend of all reference points of all combustibles to obtain the secondary determination range. Step S202.9: The initial determination threshold and the secondary determination range together constitute the heat source heat diffusion relationship; In the specific implementation, the heat will gradually decrease during the transfer process, and the change range will become smaller and smaller, so RA j will decrease as j increases, but for different objects and different temperatures, RA j The reduction rate is not fixed, but is related to TCT, so the calculation of GA j , the secondary judgment analysis diagram is constructed as follows Figure 7 As shown, the slope change trend is -0.0105, and the secondary judgment range is [-0.0189, -0.0098].
[0022] Step S3, performing flame retardancy tests on the conventional experimental group and the oil pollution experimental group respectively, photographing the automotive wiring harness using a thermal imaging device to obtain test images; Step S3 includes the following sub-steps: Step S301: randomly select a point on the automobile wiring harness as a test point, irradiate the test point with thermal radiation, and ensure that the thermal radiation is focused on the test point during irradiation; Step S302: photographing the conventional wiring harness with a thermal imaging device to obtain a conventional test image, and photographing the oily wiring harness with a thermal imaging device to obtain an oily test image. The conventional test image and the oily test image are test images. In specific implementation, thermal radiation is different from traditional open flame heating. Open flame heating will cause heat transfer around it, which will affect the judgment result when extracting flame retardant data, while thermal radiation will not cause heat transfer. It is similar to a convex lens focusing sunlight to heat it within a point. The selection of test points is completely random.
[0023] Step S4, analyzing the test image based on the heat source heat diffusion relationship to obtain accurate flame retardant data of the automotive wiring harness; Step S4 includes the following sub-steps: Step S401: constructing a flame retardant data analysis model and defining an analysis process for accurate flame retardant data; Step S401 includes the following sub-steps: Step S401.1, constructing a flame retardant data analysis model, and when analyzing any test image, naming it as an image to be analyzed; See also Figure 8As shown, in step S401.2, based on the analysis process of the preliminary determination threshold and the secondary determination range, the geometric center of the test point is used as the reference point, and diffusion auxiliary lines are drawn directly above, directly below, directly to the left, and directly to the right of the reference point. The reference point and diffusion auxiliary lines of the image to be analyzed are named reference analysis point and diffusion analysis line, respectively. Step S401.3, naming the diffusion analysis lines corresponding to the upper, lower, left, and right directions as the upper line, lower line, left line, and right line, respectively; See also Figure 9 As shown, in step S401.4, when analyzing any one of the upper line, lower line, left line, and right line, it is named as the line to be analyzed, and any pixel point on the line to be analyzed is assumed to be the end point and the corresponding heat source floating range and boundary floating range are analyzed, which are named as the first floating range and the second floating range respectively; Step S401.5, determining whether the minimum value of the first floating range is greater than the preliminary determination threshold while the maximum value of the second floating range is less than the preliminary determination threshold. If so, output a preliminary verification pass signal; otherwise, output a preliminary verification fail signal. In the specific implementation, in order to facilitate the understanding of the definition of reference points and diffusion auxiliary lines, this embodiment constructs Figure 8 The reference point and diffusion auxiliary line are explained. The test point is not a point, but a circular area. The reference analysis point is the pixel point corresponding to the center of the test point. Figure 8 The diffusion analysis line in the example is the positive right line. Similarly, there are positive left line, positive upper line and positive lower line. Since the positive upper line and positive lower line are the circumference of the automobile wiring harness, there may be errors when analyzing the combustion length and they cannot be represented in one figure. Therefore, the positive upper line and positive lower line are usually not analyzed. Only the positive left line and positive right line are analyzed. Figure 8 Taking the right line in the figure as the line to be analyzed as an example, since heat diffusion is most obvious within 30 pixels in this embodiment, after selecting any pixel as the end point, the 30 pixels in the opposite direction from the end point to the reference analysis point are used as diffusion points for analysis. For example, Figure 9 As shown, Figure 9The gray solid circle in the figure is the assumed end point, and the dotted line behind the assumed end point is 30 pixels long. The pixels on the dotted line are the diffusion points mentioned in step S201.4, the pixels on the solid line are the heat source points mentioned in step S201.4, and the diffusion points adjacent to the end point are the unburned points. Based on the above premise, the first floating range and the second floating range are obtained by analyzing the heat source floating range and the boundary floating range in step S202, which are [0.2869, 1.5348] and [0.0634, 0.0946] respectively. The minimum value of the first floating range is 0.2869, which is greater than the preliminary judgment threshold. The maximum value of the second floating range is 0.0946, which is less than the preliminary judgment threshold. The condition is met and a preliminary verification pass signal is output; Step S401.6: If a preliminary verification pass signal is output, the corresponding slope change trend is analyzed, named the trend to be analyzed, and it is determined whether the trend to be analyzed is within the secondary determination range. If so, a burned signal is output; if not, an unburned signal is output; In the specific implementation, since the preliminary verification pass signal is output, the slope change trend is further analyzed and the trend to be analyzed is -0.0242, which is not within the secondary judgment range. The unburned signal is output, which means that based on Figure 9 When analyzing the assumed end point, the car harness did not burn. Since heat radiation will cause the test point to burn first, this embodiment needs to select the end point according to certain rules. When selecting for the first time, the pixel point at the intersection of the diffusion auxiliary line and the boundary of the test point is selected as the end point for priority analysis, that is, Figure 9 At the end point shown, when any pixel outputs a burned signal, the next pixel is searched in the direction away from the test point as the end point to continue the analysis. However, the pixel corresponding to the burned signal also needs to be continuously analyzed. At the same time, there are multiple hypothetical end points for analysis. For example, point A is the reference analysis point, point B is the pixel at the intersection of the diffusion auxiliary line and the boundary of the test point, there are 10 points to be analyzed between points A and B, and point C is 30 points to be analyzed from point B and is on the diffusion auxiliary line. Point B is used as the end point for the first analysis. When the burned signal is output, the point to be analyzed between points B and C is obtained. The point to be analyzed adjacent to point B is used as the end point for analysis. It is assumed to be point D. At this time, points B and D need to be analyzed at the same time, and so on. Step S401.7: While radiating heat to the test point, start the timer. When the burn signal is output, record the timer time, which is called the anti-burning duration. Then stop radiating heat and reset the timer. Check whether the burn signal is output. If so, continue the timer timer. If not, record the timer time, which is called the self-extinguishing duration. Step S401.8: If a burned signal is output when any pixel point is assumed to be the end point for analysis, the corresponding pixel point is marked as the burn end point. All burn end points are counted, and the burn end point farthest from the reference analysis point is obtained, named the length reference point. The distance between the length reference point and the reference analysis point is obtained, named the burn length. Step S401.9: The anti-burning time, self-extinguishing time, and burning length are the accurate flame retardant data; In specific implementations, the anti-burning duration is recorded when a burning signal is first detected. When all assumed end points output an unburned signal during analysis, the analysis is stopped and the self-extinguishing duration is recorded. The burning length can be directly obtained based on the pixel length. The precise flame retardant data obtained at this time is more accurate than that obtained by traditional testing methods, and can achieve pixel-level combustion judgment. Step S402: Analyze the conventional test image and the oil stain test image using a flame retardant data analysis model to obtain accurate conventional flame retardant data and accurate oil stain flame retardant data, respectively. Step S402 includes the following sub-steps: Step S402.1: Analyze the conventional test image using a flame retardant data analysis model to obtain accurate conventional flame retardant data, including conventional anti-burning time, conventional self-extinguishing time, and conventional burning length; Step S402.2: Analyze the oil stain test image using a flame retardant data analysis model to obtain accurate oil stain flame retardant data, including the oil stain's anti-burning time, the oil stain's self-extinguishing time, and the oil stain's burning length. In the specific implementation, the definitions of conventional anti-burning time, conventional self-extinguishing time, conventional combustion length, oil pollution anti-burning time, oil pollution self-extinguishing time and oil pollution combustion length have been clearly given, and will not be described in detail in this embodiment.
[0024] Step S5, performing flame retardancy analysis on the precise flame retardancy data to evaluate whether the flame retardancy of the automotive wiring harness is qualified; Step S5 includes the following sub-steps: Step S501, determining whether the conventional anti-burning time, conventional self-extinguishing time, conventional combustion length, oil pollution anti-burning time, oil pollution self-extinguishing time, and oil pollution combustion length meet safety standards. If all meet the safety standards, a flame retardant qualified signal is output; otherwise, a flame retardant unqualified signal is output; Step S502: If a flame retardant qualified signal is output, the flame retardancy of the automobile wiring harness is marked as qualified; if a flame retardant unqualified signal is output, the flame retardancy of the automobile wiring harness is marked as unqualified; In specific implementation, when evaluating whether the flame retardancy of automobile wiring harnesses is qualified, a comparison and judgment is made based on existing safety standards. The method is relatively simple and will not be described in detail in this embodiment. This embodiment focuses on obtaining accurate flame retardant data.
[0025] In embodiment 2, the present application provides an electronic device, which may include: a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus. The memory stores computer-readable instructions, and the processor can call the instructions in the memory. When the computer-readable instructions are executed by the processor, the steps in a method for testing the flame retardancy of an automotive wiring harness are executed to achieve the following functions: dividing the automotive wiring harness into a conventional experimental group and an oil-contaminated experimental group, and constructing a heat source analysis group; analyzing the heat source heat diffusion relationship through the heat source analysis group; performing flame retardancy tests on the conventional experimental group and the oil-contaminated experimental group respectively, photographing the automotive wiring harness using a thermal imaging device to obtain test images; analyzing the test images based on the heat source heat diffusion relationship to obtain accurate flame retardancy data of the automotive wiring harness; performing flame retardancy analysis on the accurate flame retardancy data to evaluate whether the flame retardancy of the automotive wiring harness is qualified.
[0026] In addition, the logical instructions in the above-mentioned memory can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present application, or the part that contributes to the existing technology, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, and other media that can store program code.
[0027] Example 3. The present application also provides a computer program product, which includes a computer program stored on a computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute a method for testing the flame retardancy of an automobile wiring harness provided by the above methods, the method including: dividing the automobile wiring harness into a conventional experimental group and an oil pollution experimental group, and constructing a heat source analysis group at the same time; analyzing the heat source heat diffusion relationship through the heat source analysis group; performing flame retardancy tests on the conventional experimental group and the oil pollution experimental group respectively, and photographing the automobile wiring harness through a thermal imaging device to obtain a test image; analyzing the test image based on the heat source heat diffusion relationship to obtain accurate flame retardant data of the automobile wiring harness; performing flame retardancy analysis on the accurate flame retardant data to evaluate whether the flame retardancy of the automobile wiring harness is qualified.
[0028] Example 4. The present application also provides a computer-readable storage medium. The present application provides a storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method for testing the flame retardancy of an automobile wiring harness are executed to achieve the following functions: the automobile wiring harness is divided into a conventional experimental group and an oil pollution experimental group, and a heat source analysis group is constructed at the same time; the heat source heat diffusion relationship is analyzed by the heat source analysis group; flame retardancy tests are performed on the conventional experimental group and the oil pollution experimental group respectively, and the automobile wiring harness is photographed by a thermal imaging device to obtain a test image; the test image is analyzed based on the heat source heat diffusion relationship to obtain accurate flame retardant data of the automobile wiring harness; flame retardancy analysis is performed on the accurate flame retardant data to evaluate whether the flame retardancy of the automobile wiring harness is qualified.
[0029] Through the description of the above embodiments, the embodiments of the present invention can be provided as methods, systems, or computer program products. Based on this understanding, the essence of the above technical solutions or the portion that contributes to the prior art can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for enabling a computer device (such as a personal computer, server, or network device) to execute the methods described in various embodiments or certain portions of the embodiments.
[0030] In the embodiments provided in this application, it should be understood that the disclosed system or method can be implemented in other ways. The embodiments described above are merely illustrative. For example, the division of modules or units is only a logical function division. There may be other division methods in actual implementation. For example, multiple modules or units can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of systems, modules and units can be electrical, mechanical or other forms.
[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims
1. A method for testing the flame retardancy of automotive wiring harnesses, characterized in that: The steps include: The automotive wiring harnesses were divided into two flame retardant test groups, including a conventional test group and an oil pollution test group, and a heat source analysis group was constructed at the same time; Analyze the heat source heat diffusion relationship through the heat source analysis group; The flame retardancy tests were conducted on the conventional experimental group and the oil pollution experimental group respectively. The automotive wiring harness was photographed using a thermal imaging device to obtain test images. Analyze the test image based on the heat source heat diffusion relationship to obtain accurate flame retardant data of automotive wiring harnesses; Conduct flame retardancy analysis on precise flame retardant data to evaluate whether the flame retardancy of automotive wiring harnesses is qualified.
2. The method for testing flame retardancy of automotive wiring harnesses according to claim 1, wherein: The automotive wiring harness is divided into two flame retardant test groups, which include a conventional test group and an oil pollution test group. At the same time, the heat source analysis group is constructed, which includes the following sub-steps: The automotive wiring harnesses were divided into two flame retardant test groups: conventional test group and oil pollution test group; The automotive wiring harness in the conventional experimental group is named conventional wiring harness, and the automotive wiring harness in the oily experimental group is named oily wiring harness. The conventional wiring harness and the oily wiring harness are exactly the same. Soak the oily wiring harness in the engine oil for a short time and then dry it, repeating the first time; A heat source analysis group is constructed, wherein different types of combustibles are arranged in the heat source analysis group, and the combustibles have a fixed form.
3. The method for testing flame retardancy of automotive wiring harnesses according to claim 2, wherein: Analyzing the heat source heat diffusion relationship through the heat source analysis group includes the following sub-steps: Ignite the combustible material and take a heat source diffusion analysis diagram; The heat source diffusion analysis diagram is analyzed to obtain the heat source heat diffusion relationship.
4. The method for testing flame retardancy of automotive wiring harnesses according to claim 3, wherein: Ignition of combustible materials and taking heat source diffusion analysis diagrams include the following sub-steps: Ignite the combustible material and ensure that all surfaces of the combustible material are in a burning state; Use thermal imaging devices to photograph combustibles in a burning state and obtain a heat source diffusion analysis diagram; Extract the outline of the combustibles in the heat source diffusion analysis diagram to obtain the object outline; The heat source diffusion analysis map is converted into a grayscale map, named as a heat source grayscale map, the pixel points within the object outline in the heat source grayscale map are named as heat source points, and the pixel points outside the object outline in the heat source grayscale map are named as diffusion points; A first number of heat source points are randomly selected and named as reference points. The diffusion points closest to the reference points are found and named as direction points. Different reference points correspond to different direction points.
5. The method for testing flame retardancy of automotive wiring harnesses according to claim 4, wherein: Analyzing the heat source diffusion analysis diagram to obtain the heat source heat diffusion relationship includes the following sub-steps: Analyze any reference point, construct a ray with the reference point as the endpoint and the direction point as the direction, and name it the diffusion auxiliary line. Name the pixel points on the diffusion auxiliary line as the points to be analyzed. Starting from the endpoint of the diffusion auxiliary line, the points to be analyzed are numbered along the direction of the diffusion auxiliary line, and the symbol P is used. n Indicates that n is a non-zero natural number and n is the sequence number of P; Extraction of P n Gray value, marked as H n , with serial number n as X axis, H n Establish a two-dimensional coordinate system for the Y axis, named heat source heat diffusion diagram, and set H n Enter the heat source heat diffusion diagram according to n, and name the coordinate points in the heat source heat diffusion diagram as heat source heat diffusion coordinates; Connect the heat diffusion coordinates of two adjacent heat sources with a straight line to obtain a change trend line, and obtain the slope of the change trend line, which is named the heat change trend; Obtain two pixel points corresponding to the intersection of the heat source point and the diffusion point in the diffusion auxiliary line, name the diffusion point as the unburned point, and name the heat source point as the end point; Obtain the heat change trend between the termination point and the unburned point, name it the combustion termination trend, mark it as TCT, and number the heat change trends before TCT in order from front to back, using the symbol RF i Indicates that the heat change trend after TCT is numbered, and the symbol RA j Indicates that both i and j are non-zero natural numbers, i is the serial number of RF, and j is the serial number of RA; For each value of i, calculate |RF i / RF i+1 |, mark the result as GF i , the GF i There is no GF in max(i) , the max() is the maximum value operator, and then calculate |RF max(i) / TFT|, mark the calculation result as GT; Analyze and calculate the GF of all reference points of all combustibles i As well as GT, statistical GF i The range of and GT are named heat source floating range and boundary floating range respectively. The average value of the minimum value of the heat source floating range and the maximum value of the boundary floating range are calculated to obtain the preliminary judgment threshold of the boundary. For each value of j, calculate RA j / TFT, mark the calculation result as GA j , with j as the horizontal axis, GA j Establish a two-dimensional coordinate system for the vertical axis, named as the secondary decision analysis diagram, and use GA j Enter j into the secondary determination analysis chart, perform linear regression analysis on the secondary determination analysis chart, obtain the slope of the regression function, and name it the slope change trend. Analyze and count the range of the slope change trend of all reference points of all combustibles to obtain the secondary determination range. The preliminary determination threshold and the secondary determination range together constitute the heat source heat diffusion relationship.
6. The method for testing flame retardancy of automotive wiring harnesses according to claim 5, characterized in that: The flame retardancy test was conducted on the conventional experimental group and the oil pollution experimental group respectively. The automotive wiring harness was photographed by a thermal imaging device to obtain the test image, which includes the following sub-steps: Randomly select a point on the car wiring harness as a test point, irradiate the test point with thermal radiation, and ensure that the thermal radiation is focused on the test point during irradiation; A conventional test image is obtained by photographing a conventional wiring harness with a thermal imaging device, and an oily wiring harness is photographed with a thermal imaging device to obtain an oily test image. The conventional test image and the oily test image are test images.
7. The method for testing flame retardancy of automotive wiring harnesses according to claim 6, wherein: Analyzing the test image based on the heat source heat diffusion relationship to obtain accurate flame retardant data for automotive wiring harnesses includes the following sub-steps: Build a flame retardant data analysis model and define the analysis process for accurate flame retardant data; The conventional test chart and the oil stain test chart are analyzed by the flame retardant data analysis model to obtain accurate conventional flame retardant data and accurate oil stain flame retardant data respectively.
8. The method for testing flame retardancy of automotive wiring harnesses according to claim 7, wherein: The flame retardant data analysis model is constructed and the analysis process of defining accurate flame retardant data includes the following sub-steps: Construct a flame retardant data analysis model. When analyzing any test image, name it as the image to be analyzed; Based on the analysis process of the preliminary judgment threshold and the secondary judgment range, the geometric center of the test point is used as the reference point, and diffusion auxiliary lines are drawn directly above, directly below, directly to the left, and directly to the right of the reference point. The reference point of the image to be analyzed and the diffusion auxiliary lines are named reference analysis point and diffusion analysis line respectively. The diffusion analysis lines corresponding to the top, bottom, left, and right are named as the top line, bottom line, left line, and right line respectively; When analyzing any one of the upper line, lower line, left line, and right line, it is named as the line to be analyzed. Any pixel point on the line to be analyzed is assumed to be the end point and the corresponding heat source floating range and boundary floating range are analyzed, which are named the first floating range and the second floating range respectively. Determine whether the minimum value of the first floating range is greater than the preliminary determination threshold while the maximum value of the second floating range is less than the preliminary determination threshold. If so, output a preliminary verification pass signal; otherwise, output a preliminary verification fail signal. If the output is a preliminary verification pass signal, the corresponding slope change trend is analyzed and named as the trend to be analyzed. It is determined whether the trend to be analyzed is within the secondary judgment range. If so, a burned signal is output; if not, an unburned signal is output; While radiating heat to the test point, start the timer. When the burn signal is output, record the timer time, which is named as the anti-burning time. Then stop the heat radiation and reset the timer. Check whether the burn signal is output. If so, continue to count. If not, record the timer time, which is named as the self-extinguishing time. If a burned signal is output when any pixel point is assumed to be the end point for analysis, the corresponding pixel point is marked as the burning end point. All the burning end points are counted, and the burning end point farthest from the reference analysis point is obtained and named the length reference point. The distance between the length reference point and the reference analysis point is obtained and named the burning length. The anti-burning time, self-extinguishing time and burning length are precise flame retardant data.
9. The method for testing flame retardancy of automotive wiring harnesses according to claim 8, characterized in that: Analyzing the conventional test chart and the oil stain test chart using the flame retardant data analysis model to obtain accurate conventional flame retardant data and accurate oil stain flame retardant data respectively includes the following sub-steps: Analyze conventional test images through the flame retardant data analysis model to obtain accurate conventional flame retardant data, including conventional anti-burning time, conventional self-extinguishing time and conventional burning length; The oil stain test image is analyzed through the flame retardant data analysis model to obtain accurate oil stain flame retardant data, including the oil stain anti-burning time, oil stain self-extinguishing time and oil stain burning length.
10. The method for testing flame retardancy of automotive wiring harnesses according to claim 9, wherein: Conducting flame retardancy analysis on precise flame retardant data to evaluate whether the flame retardancy of automotive wiring harnesses is qualified includes the following sub-steps: Determine whether the conventional anti-burning time, conventional self-extinguishing time, conventional burning length, oil pollution anti-burning time, oil pollution self-extinguishing time and oil pollution burning length meet the safety standards. If all meet the safety standards, output a flame retardant qualified signal; otherwise, output a flame retardant unqualified signal; If a flame retardant qualified signal is output, the flame retardancy of the automobile wiring harness is marked as qualified; if a flame retardant unqualified signal is output, the flame retardancy of the automobile wiring harness is marked as unqualified.