A fault diagnosis system for automobile engines

Abstract

This invention relates to the field of engine fault detection, and more particularly to a fault diagnosis system for automotive engines. The invention comprises a detection module, an image module, and a fault diagnosis module. The image acquisition unit in the image module generates crankshaft centerline trajectory images at different detection positions based on engine crankshaft vibration data acquired by the detection module. The image analysis unit in the image module acquires information from several trajectory points based on the crankshaft centerline trajectory images and calculates the maximum difference between them to determine the abnormal state of the engine crankshaft and the location of the fault. The fault diagnosis module determines the cause of the engine crankshaft fault based on the abnormal state determined by the image analysis unit. This high-precision detection method using crankshaft centerline trajectory images enables accurate detection of the engine crankshaft, and the characteristic quantities of the crankshaft centerline trajectory image are used to determine the cause of the engine fault, thereby improving the accuracy and reliability of engine fault diagnosis.

Description

Technical Field

[0001] This invention relates to the field of engine fault detection, and more particularly to a fault diagnosis system for automobile engines. Background Technology

[0002] my country is a major automobile manufacturing and consumer country. The automobile engine is an important component of automobiles, serving as the power source and affecting the vehicle's performance and driving safety. The crankshaft is a crucial part of the automobile engine. During engine operation, the crankshaft is subjected to bending and torsional loads, making its various performance indicators particularly important. Therefore, crankshaft fault detection is especially important in engine fault detection, leading to the development of various related testing systems and devices.

[0003] Traditional engine fault detection devices use simulation environments to simulate various engine operating conditions and then use the simulation model to detect the actual engine. However, traditional engine fault detection devices can only detect problems corresponding to simulated operating conditions and cannot take into account the complexity of the actual environment, resulting in low accuracy of fault detection.

[0004] There is currently no effective solution to the above problems. Summary of the Invention

[0005] To address the above problems, the present invention provides a fault diagnosis system for an automobile engine, comprising:

[0006] The detection module includes a front shaft vibration detection unit disposed on the front shaft of the engine crankshaft for detecting the vibration of the front shaft of the engine crankshaft, and a rear shaft vibration detection unit disposed on the rear shaft of the engine crankshaft for detecting the vibration of the rear shaft of the engine crankshaft.

[0007] An image module includes an image acquisition unit and an image parsing unit connected to each other. The image acquisition unit is connected to the detection module to generate a front shaft center trajectory image based on the data detected by the front shaft vibration detection unit and to generate a rear shaft center trajectory image based on the data detected by the rear shaft vibration detection unit.

[0008] The image analysis unit calculates a first difference based on the distance values ​​from each point on the front axis trajectory image to the origin of the rectangular coordinate system and the first average distance value from each point on the front axis trajectory image to the origin of the rectangular coordinate system. Based on the comparison result of the filtered maximum value of the first difference and the first difference comparison value, it determines whether there is an abnormality in the front axis of the engine crankshaft. Furthermore, it determines the abnormal state of the front axis of the engine crankshaft based on the comparison result of the maximum value of the first difference and the first abnormality characterization value. Both the first difference comparison value and the first abnormality characterization value are calculated based on the first average distance value.

[0009] The second difference is calculated based on the distance values ​​from each point on the rear shaft center trajectory image to the origin of the rectangular coordinate system and the second average distance value from each point on the rear shaft center trajectory image to the origin of the rectangular coordinate system. Based on the comparison result of the maximum value of the second difference and the comparison value of the second difference, it is determined whether there is an abnormality in the rear shaft of the engine crankshaft. Furthermore, the abnormal state of the rear shaft of the engine crankshaft is determined based on the comparison result of the maximum value of the second difference and the second abnormality characterization value. Both the second difference comparison value and the second abnormality characterization value are calculated based on the second average distance value.

[0010] A fault diagnosis module, connected to the image analysis unit, is used to determine the cause of the fault in the front and rear shafts of the engine crankshaft when the image analysis unit determines that the front and rear shafts of the engine crankshaft are in an abnormal state.

[0011] Furthermore, the front shaft vibration detection unit includes two eddy current vibration sensors arranged in a surrounding manner on the front shaft of the engine crankshaft, and the angle formed by the line connecting the two eddy current vibration sensors and the shaft center is 90°.

[0012] Furthermore, the rear shaft vibration detection unit includes two eddy current vibration sensors arranged in a surrounding manner on the rear shaft of the engine crankshaft, and the angle formed by the line connecting the two eddy current vibration sensors and the shaft center is 90°.

[0013] Furthermore, the image acquisition unit establishes a rectangular coordinate system, acquires the vibration vector signal in the X-axis direction and the vibration vector signal in the Y-axis direction detected by the front-end shaft vibration detection unit, and performs vector superposition to obtain a first superimposed vector. The origin of the rectangular coordinate system is taken as the starting point of the first superimposed vector, and the ending point of the first superimposed vector is determined as the front-end shaft center trajectory point. After acquiring several front-end shaft center trajectory points, a front-end shaft center trajectory image is obtained.

[0014] Furthermore, the image acquisition unit establishes a rectangular coordinate system, acquires the vibration vector signals in the X-axis direction and the vibration vector signals in the Y-axis direction detected by the rear shaft vibration detection unit, and performs vector superposition to obtain a second superimposed vector. The origin of the rectangular coordinate system is taken as the starting point of the second superimposed vector, and the ending point of the second superimposed vector is determined as the rear shaft center trajectory point. After acquiring several rear shaft center trajectory points, a rear shaft center trajectory image is obtained.

[0015] Furthermore, the image analysis unit establishes a rectangular coordinate system based on the front-end axis trajectory image and the rear-end axis trajectory image, and calculates the first average distance from each point on the front-end axis trajectory image to the origin of the rectangular coordinate system according to formula (1). And calculate the second average distance from each point on the rear axis trajectory image to the origin of the rectangular coordinate system according to formula (2). ,

[0016] (1)

[0017] In formula (1), This represents the distance from the i-th point in the front axis trajectory image to the origin of the rectangular coordinate system, where n represents the number of points in the front axis trajectory image, and i represents an integer greater than 0.

[0018] (2)

[0019] In formula (2), The distance from the i-th point in the rear axis trajectory image to the origin of the rectangular coordinate system is represented by m, where m represents the number of points in the rear axis trajectory image, and i represents an integer greater than 0.

[0020] Furthermore, the image analysis unit calculates the first difference between the distance from each point on the front-end axis trajectory image to the origin of the rectangular coordinate system and the first average distance value according to formula (3). ,

[0021] (3)

[0022] Calculate the distance from each point on the rear axis trajectory image to the origin of the rectangular coordinate system and the second average distance using formula (4). The second difference ,

[0023] (4)

[0024] Furthermore, the image analysis unit selects the maximum value of the first difference. and the second maximum difference .

[0025] Furthermore, the image analysis unit will determine the maximum value of the first difference. Comparison with the first difference value Compare the two values ​​and take the maximum value of the second difference. Comparison with the second difference value In comparison, among them,

[0026] Based on the first difference comparison result, the image analysis unit determines that the front end shaft of the engine crankshaft is abnormal;

[0027] Based on the second difference comparison result, the image analysis unit determines that there is no abnormality in the front end shaft of the engine crankshaft;

[0028] Based on the third difference comparison result, the image analysis unit determines that the rear end shaft of the engine crankshaft is abnormal;

[0029] Based on the fourth difference comparison result, the image analysis unit determines that there is no abnormality in the rear end shaft of the engine crankshaft;

[0030] Wherein, the first difference comparison result is that the maximum value of the first difference is greater than the first difference comparison value; the second difference comparison result is that the maximum value of the first difference is less than or equal to the first difference comparison value; the third difference comparison result is that the maximum value of the second difference is greater than the second difference comparison value; and the fourth difference comparison result is that the maximum value of the second difference is less than or equal to the second difference comparison value. , .

[0031] Furthermore, when the image analysis unit determines that the front end shaft or the rear end shaft of the engine crankshaft is abnormal, it sets the maximum value of the first difference. Compared with the first anomaly characterization value Compare the two values ​​and take the maximum value of the second difference. Compared with the second anomaly characterization value In comparison, among them,

[0032] Under the first comparison condition, the image analysis unit determines that the abnormal state of the engine crankshaft front end shaft is the first abnormal state;

[0033] Under the second comparison condition, the image analysis unit determines that the abnormal state of the engine crankshaft front end shaft is the second abnormal state;

[0034] Under the third comparison condition, the image analysis unit determines that the abnormal state of the engine crankshaft rear end shaft is the first abnormal state;

[0035] Under the fourth comparison condition, the image analysis unit determines that the abnormal state of the engine crankshaft rear end shaft is the second abnormal state;

[0036] Wherein, the first comparison condition is that the maximum value of the first difference is less than or equal to the first anomaly characteristic value; the second comparison condition is that the maximum value of the first difference is greater than the first anomaly characteristic value; the third comparison condition is that the maximum value of the second difference is less than or equal to the second anomaly characteristic value; and the fourth comparison condition is that the maximum value of the second difference is greater than the second anomaly characteristic value, and the first anomaly characteristic value... The second abnormal characterization value .

[0037] Furthermore, based on the abnormal state determined by the image analysis unit, the fault diagnosis module determines the cause of the fault in the front and rear shafts of the engine crankshaft.

[0038] If the image analysis unit determines that the front end shaft of the engine crankshaft is in a first abnormal state, then the fault diagnosis module determines that the cause of the fault in the front end shaft of the engine crankshaft is misalignment or friction.

[0039] If the image analysis unit determines that the front end of the engine crankshaft is in a second abnormal state, then the fault diagnosis module determines that the cause of the fault in the front end of the engine crankshaft is oil film oscillation or cracks.

[0040] If the image analysis unit determines that the engine crankshaft rear end shaft is in a first abnormal state, then the fault diagnosis module determines that the cause of the engine crankshaft rear end shaft fault is misalignment or friction.

[0041] If the image analysis unit determines that the engine crankshaft rear end shaft is in a second abnormal state, then the fault diagnosis module determines that the cause of the engine crankshaft rear end shaft failure is oil film oscillation or cracks.

[0042] Compared with existing technologies, this invention sets up a detection module, an image module, and a fault diagnosis module. The image acquisition unit in the image module generates shaft center trajectory images of different detection positions of the engine crankshaft based on the engine crankshaft vibration data acquired by the detection module. The image analysis unit in the image module acquires information of several trajectory points based on the shaft center trajectory images and calculates the maximum difference to determine the abnormal state of the engine crankshaft and the location of the fault. The fault diagnosis module determines the cause of the engine crankshaft fault based on the abnormal state determined by the image analysis unit. This high-precision detection method of shaft center trajectory images enables accurate detection of the engine crankshaft, and the characteristic quantities of the shaft center trajectory image are used to determine the cause of the engine fault, thereby improving the accuracy and reliability of engine fault diagnosis.

[0043] In particular, the present invention provides eddy current vibration sensors on both the front and rear shafts of the engine crankshaft. The sway amplitude of the front and rear shafts is small, which allows for the acquisition of more accurate shaft center trajectory images. This makes the judgment of the engine crankshaft's operating status based on the shaft center trajectory images more accurate, thereby improving the accuracy of engine fault diagnosis.

[0044] In particular, this invention generates shaft center trajectory images at different positions of the engine crankshaft by acquiring data from vibration sensors through an image acquisition unit. The shaft center trajectory refers to the movement trajectory of the crankshaft journal center relative to the vertical plane of the bearing housing. It more intuitively reflects the movement of the shaft, especially the vibration. By judging the shape of the shaft center trajectory, the cause of engine crankshaft vibration can be further analyzed, thereby improving the accuracy and reliability of engine fault diagnosis.

[0045] In particular, the present invention calculates the difference between the distance value from each point on the shaft center trajectory image to the origin of the rectangular coordinate system and the average distance value through the image analysis unit. In actual practice, the magnitude of the difference characterizes the vibration amplitude of the crankshaft. The vibration amplitude can be used to determine whether there is an abnormality in the crankshaft when the engine is running. Furthermore, the image type can be determined based on the shaft center trajectory image, thereby improving the accuracy and reliability of engine fault diagnosis.

[0046] In particular, when the image analysis unit determines that the front or rear end of the engine crankshaft is abnormal, the present invention further determines the abnormal state of the front or rear end of the engine crankshaft. In reality, when the engine crankshaft is abnormal, the crankshaft's axis trajectory may only show abnormality at one end due to different vibration amplitudes. Therefore, detecting only the axis trajectory at one end of the crankshaft can easily miss abnormal phenomena. The present invention can improve the reliability of the diagnostic system and the accuracy of fault diagnosis by detecting both ends of the crankshaft. Attached Figure Description

[0047] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0048] Figure 1 A structural block diagram of a fault diagnosis system for an automobile engine according to an embodiment of the invention;

[0049] Figure 2 This is a side view of the detection module of an embodiment of the invention, arranged on the engine crankshaft.

[0050] Figure 3 The left view of the detection module of the embodiment of the invention is arranged on the front end of the engine crankshaft.

[0051] Figure 4 This is a schematic diagram of the shaft center trajectory of the front end shaft of the engine crankshaft under a first abnormal state, according to an embodiment of the invention.

[0052] Figure 5 This is a schematic diagram of the shaft center trajectory of the front end shaft of the engine crankshaft under a second abnormal state, according to an embodiment of the invention.

[0053] In the diagram, 1 represents the front crankshaft of the engine, 2 represents the front crankshaft vibration detection unit, 3 represents the rear crankshaft of the engine, and 4 represents the rear crankshaft vibration detection unit. This represents the first average distance value. This represents the distance from the i-th point in the front axis trajectory image to the origin of the rectangular coordinate system. Detailed Implementation

[0054] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0055] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0056] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0057] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0058] Please see Figure 1 The diagram shown is a structural block diagram of a fault diagnosis system for an automobile engine according to an embodiment of the present invention. The fault diagnosis system for an automobile engine according to the present invention includes:

[0059] The detection module includes a front shaft vibration detection unit 2 disposed on the front shaft 1 of the engine crankshaft for detecting the vibration of the front shaft 1 of the engine crankshaft, and a rear shaft vibration detection unit 4 disposed on the rear shaft 3 of the engine crankshaft for detecting the vibration of the rear shaft 3 of the engine crankshaft.

[0060] An image module includes an image acquisition unit and an image parsing unit connected to each other. The image acquisition unit is connected to the detection module to generate a front shaft center trajectory image based on the data detected by the front shaft vibration detection unit 2, and to generate a rear shaft center trajectory image based on the data detected by the rear shaft vibration detection unit 4.

[0061] The image analysis unit calculates a first difference based on the distance values ​​from each point on the front axis trajectory image to the origin of the rectangular coordinate system and the first average distance value from each point on the front axis trajectory image to the origin of the rectangular coordinate system. Based on the comparison result of the filtered maximum value of the first difference and the comparison value of the first difference, it determines whether there is an abnormality in the front axis 1 of the engine crankshaft. Furthermore, it determines the abnormal state of the front axis 1 of the engine crankshaft based on the comparison result of the maximum value of the first difference and the first abnormality characterization value. Both the first difference comparison value and the first abnormality characterization value are calculated based on the first average distance value.

[0062] The second difference is calculated based on the distance values ​​from each point on the rear shaft center trajectory image to the origin of the rectangular coordinate system and the second average distance value from each point on the rear shaft center trajectory image to the origin of the rectangular coordinate system. Based on the comparison result of the maximum value of the second difference and the comparison value of the second difference, it is determined whether there is an abnormality in the rear shaft 3 of the engine crankshaft. Furthermore, the abnormal state of the rear shaft 3 of the engine crankshaft is determined based on the comparison result of the maximum value of the second difference and the second abnormality characterization value. Both the second difference comparison value and the second abnormality characterization value are calculated based on the second average distance value.

[0063] A fault diagnosis module, which is connected to the image analysis unit, is used to determine the cause of the fault in the front end shaft 1 and the rear end shaft 3 of the engine crankshaft when the image analysis unit determines that the front end shaft 1 and the rear end shaft 3 of the engine crankshaft are in an abnormal state.

[0064] Specifically, the present invention does not limit the specific structure of the image module and the fault diagnosis module. They themselves and their units can be constructed using logic components. The logic components can be field-programmable logic components, microprocessors, processors used in computers, etc., which will not be elaborated here.

[0065] Specifically, please refer to Figure 2 as well as Figure 3 As shown, Figure 2 This is a side view of the detection module of the invention arranged on the engine crankshaft, according to an embodiment of the invention. Figure 3 The left view of the detection module of the embodiment of the invention is arranged on the front end shaft 1 of the engine crankshaft. The front end shaft vibration detection unit 2 includes two eddy current vibration sensors arranged in a surrounding manner on the front end shaft 1 of the engine crankshaft. The angle formed by the line connecting the two eddy current vibration sensors and the shaft center is 90°.

[0066] Specifically, the rear shaft vibration detection unit 4 includes two eddy current vibration sensors arranged in a surrounding manner on the rear shaft 3 of the engine crankshaft, and the angle formed by the line connecting the two eddy current vibration sensors and the shaft center is 90°.

[0067] Specifically, the present invention provides eddy current vibration sensors on both the front and rear shafts of the engine crankshaft. The sway amplitude of the front and rear shafts is small, which allows for the acquisition of more accurate shaft center trajectory images. This makes the judgment of the engine crankshaft's operating status based on the shaft center trajectory images more accurate, thereby improving the accuracy of engine fault diagnosis.

[0068] Specifically, the image acquisition unit establishes a rectangular coordinate system, acquires the vibration vector signals in the X-axis direction and the vibration vector signals in the Y-axis direction detected by the front-end shaft vibration detection unit 2, and performs vector superposition to obtain a first superimposed vector. The origin of the rectangular coordinate system is taken as the starting point of the first superimposed vector, and the ending point of the first superimposed vector is determined as the front-end shaft center trajectory point. After acquiring several front-end shaft center trajectory points, a front-end shaft center trajectory image is obtained.

[0069] Specifically, the image acquisition unit establishes a rectangular coordinate system, acquires the vibration vector signals in the X-axis direction and the vibration vector signals in the Y-axis direction detected by the rear shaft vibration detection unit 4, and performs vector superposition to obtain a second superimposed vector. The origin of the rectangular coordinate system is taken as the starting point of the second superimposed vector, and the ending point of the second superimposed vector is determined as the rear shaft center trajectory point. After acquiring several rear shaft center trajectory points, the rear shaft center trajectory image is obtained.

[0070] Specifically, this invention uses an image acquisition unit to collect data from a vibration sensor to generate images of the crankshaft's center trajectory at different positions. The center trajectory refers to the movement trajectory of the crankshaft journal center relative to the vertical plane of the bearing housing. It more intuitively reflects the movement of the shaft, especially the vibration. By judging the shape of the center trajectory, the cause of the engine crankshaft vibration can be further analyzed, thereby improving the accuracy and reliability of engine fault diagnosis.

[0071] Specifically, the image analysis unit establishes a rectangular coordinate system based on the front-end axis trajectory image and the rear-end axis trajectory image, and calculates the first average distance from each point on the front-end axis trajectory image to the origin of the rectangular coordinate system according to formula (1). And calculate the second average distance from each point on the rear axis trajectory image to the origin of the rectangular coordinate system according to formula (2). ,

[0072] (1)

[0073] In formula (1), This represents the distance from the i-th point in the front axis trajectory image to the origin of the rectangular coordinate system, where n represents the number of points in the front axis trajectory image, and i represents an integer greater than 0.

[0074] (2)

[0075] In formula (2), The distance from the i-th point in the rear axis trajectory image to the origin of the rectangular coordinate system is represented by m, where m represents the number of points in the rear axis trajectory image, and i represents an integer greater than 0.

[0076] Specifically, the image analysis unit calculates the first difference between the distance from each point on the front-end axis trajectory image to the origin of the rectangular coordinate system and the first average distance value according to formula (3). ,

[0077] (3)

[0078] Calculate the distance from each point on the rear axis trajectory image to the origin of the rectangular coordinate system and the second average distance using formula (4). The second difference ,

[0079] (4)

[0080] Furthermore, the image analysis unit selects the maximum value of the first difference. and the second maximum difference .

[0081] Specifically, the image parsing unit will use the first maximum difference value. Comparison with the first difference value Compare the two values ​​and take the maximum value of the second difference. Comparison with the second difference value In comparison, among them,

[0082] like If the image analysis unit determines that the front end shaft 1 of the engine crankshaft is abnormal;

[0083] like Then the image analysis unit determines that there is no abnormality in the front end shaft 1 of the engine crankshaft;

[0084] like If the image analysis unit determines that the rear crankshaft 3 of the engine is abnormal;

[0085] like If the image analysis unit determines that there is no abnormality in the rear end shaft 3 of the engine crankshaft;

[0086] Among them, settings, , .

[0087] Specifically, when the image analysis unit determines that the front end shaft 1 or the rear end shaft 3 of the engine crankshaft is abnormal, it sets the maximum value of the first difference. Compared with the first anomaly characterization value Compare the two values ​​and take the maximum value of the second difference. Compared with the second anomaly characterization value In comparison, among them,

[0088] like Then the image analysis unit determines that the abnormal state of the front end shaft 1 of the engine crankshaft is the first abnormal state;

[0089] like Then the image analysis unit determines that the abnormal state of the front end shaft 1 of the engine crankshaft is the second abnormal state;

[0090] like Then the image analysis unit determines that the abnormal state of the engine crankshaft rear end shaft 3 is the first abnormal state;

[0091] like Then the image analysis unit determines that the abnormal state of the engine crankshaft rear end shaft 3 is the second abnormal state;

[0092] Wherein, the first abnormal characterization value The second abnormal characterization value .

[0093] Specifically, the fault diagnosis module determines the cause of the fault in the front crankshaft 1 and the rear crankshaft 3 based on the abnormal state determined by the image analysis unit.

[0094] If the image analysis unit determines that the front end shaft 1 of the engine crankshaft is in a first abnormal state, then the fault diagnosis module determines that the cause of the fault of the front end shaft 1 of the engine crankshaft is misalignment or friction.

[0095] If the image analysis unit determines that the front end shaft 1 of the engine crankshaft is in a second abnormal state, then the fault diagnosis module determines that the cause of the fault in the front end shaft 1 of the engine crankshaft is oil film oscillation or cracks.

[0096] If the image analysis unit determines that the engine crankshaft rear end shaft 3 is in a first abnormal state, then the fault diagnosis module determines that the fault cause of the engine crankshaft rear end shaft 3 is misalignment or friction.

[0097] If the image analysis unit determines that the engine crankshaft rear end shaft 3 is in a second abnormal state, then the fault diagnosis module determines that the cause of the fault in the engine crankshaft rear end shaft 3 is oil film oscillation or cracks.

[0098] Specifically, when the image analysis unit determines that the front end shaft 1 or the rear end shaft 3 of the engine crankshaft is abnormal, the present invention further determines the abnormal state of the front end shaft 1 or the rear end shaft 3 of the engine crankshaft. In actual practice, when the engine crankshaft is abnormal, the shaft center trajectory may only show abnormality at one end due to different vibration amplitudes. Therefore, it is easy to miss abnormal phenomena by only detecting the shaft center trajectory at one end of the crankshaft. The present invention can improve the reliability of the diagnostic system and improve the accuracy of fault diagnosis by detecting both ends of the crankshaft.

[0099] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0100] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fault diagnosis system for an automobile engine, characterized in that, include: The detection module includes a front shaft vibration detection unit disposed on the front shaft of the engine crankshaft for detecting the vibration of the front shaft of the engine crankshaft, and a rear shaft vibration detection unit disposed on the rear shaft of the engine crankshaft for detecting the vibration of the rear shaft of the engine crankshaft. An image module includes an image acquisition unit and an image parsing unit connected to each other. The image acquisition unit is connected to the detection module to generate a front shaft center trajectory image based on the data detected by the front shaft vibration detection unit and to generate a rear shaft center trajectory image based on the data detected by the rear shaft vibration detection unit. The image analysis unit calculates a first difference based on the distance values ​​from each point on the front axis trajectory image to the origin of the rectangular coordinate system and the first average distance value from each point on the front axis trajectory image to the origin of the rectangular coordinate system. Based on the comparison result of the filtered maximum value of the first difference and the first difference comparison value, it determines whether there is an abnormality in the front axis of the engine crankshaft. Furthermore, it determines the abnormal state of the front axis of the engine crankshaft based on the comparison result of the maximum value of the first difference and the first abnormality characterization value. Both the first difference comparison value and the first abnormality characterization value are calculated based on the first average distance value. The second difference is calculated based on the distance values ​​from each point on the rear shaft center trajectory image to the origin of the rectangular coordinate system and the second average distance value from each point on the rear shaft center trajectory image to the origin of the rectangular coordinate system. Based on the comparison result of the maximum value of the second difference and the comparison value of the second difference, it is determined whether there is an abnormality in the rear shaft of the engine crankshaft. Furthermore, the abnormal state of the rear shaft of the engine crankshaft is determined based on the comparison result of the maximum value of the second difference and the second abnormality characterization value. Both the second difference comparison value and the second abnormality characterization value are calculated based on the second average distance value. A fault diagnosis module, connected to the image analysis unit, is used to determine the cause of the fault in the front and rear shafts of the engine crankshaft when the image analysis unit determines that the front and rear shafts of the engine crankshaft are in an abnormal state.

2. The fault diagnosis system for an automobile engine according to claim 1, characterized in that, The front-end shaft vibration detection unit includes two eddy current vibration sensors arranged in a circular manner on the front-end shaft of the engine crankshaft, and the angle formed by the line connecting the two eddy current vibration sensors and the shaft center is 90°.

3. The fault diagnosis system for an automobile engine according to claim 1, characterized in that, The rear shaft vibration detection unit includes two eddy current vibration sensors arranged in a surrounding manner on the rear shaft of the engine crankshaft, and the angle formed by the line connecting the two eddy current vibration sensors and the shaft center is 90°.

4. The fault diagnosis system for an automobile engine according to claim 1, characterized in that, The image acquisition unit establishes a rectangular coordinate system, acquires the vibration vector signals in the X-axis direction and the vibration vector signals in the Y-axis direction detected by the front-end shaft vibration detection unit, and performs vector superposition to obtain a first superimposed vector. The origin of the rectangular coordinate system is taken as the starting point of the first superimposed vector, and the ending point of the first superimposed vector is determined as the front-end shaft center trajectory point. After acquiring several front-end shaft center trajectory points, a front-end shaft center trajectory image is obtained.

5. The fault diagnosis system for an automobile engine according to claim 1, characterized in that, The image acquisition unit establishes a rectangular coordinate system, acquires the vibration vector signals in the X-axis direction and the vibration vector signals in the Y-axis direction detected by the rear shaft vibration detection unit, and performs vector superposition to obtain a second superimposed vector. The origin of the rectangular coordinate system is taken as the starting point of the second superimposed vector, and the ending point of the second superimposed vector is determined as the rear shaft center trajectory point. After acquiring several rear shaft center trajectory points, the rear shaft center trajectory image is obtained.

6. The fault diagnosis system for an automobile engine according to claim 1, characterized in that, The image analysis unit establishes a rectangular coordinate system based on the front-end axis trajectory image and the rear-end axis trajectory image, and calculates the first average distance from each point on the front-end axis trajectory image to the origin of the rectangular coordinate system according to formula (1). And calculate the second average distance from each point on the rear axis trajectory image to the origin of the rectangular coordinate system according to formula (2). , （1） In formula (1), This represents the distance from the i-th point in the front axis trajectory image to the origin of the rectangular coordinate system, where n represents the number of points in the front axis trajectory image, and i represents an integer greater than 0. （2） In formula (2), The distance from the i-th point in the rear axis trajectory image to the origin of the rectangular coordinate system is represented by m, where m represents the number of points in the rear axis trajectory image, and i represents an integer greater than 0.

7. The fault diagnosis system for an automobile engine according to claim 6, characterized in that, The image parsing unit calculates the first difference between the distance from each point on the front-end axis trajectory image to the origin of the rectangular coordinate system and the first average distance value according to formula (3). , （3） Calculate the distance from each point on the rear axis trajectory image to the origin of the rectangular coordinate system and the second average distance using formula (4). The second difference , （4） Furthermore, the image analysis unit selects the maximum value of the first difference. and the second maximum difference .

8. The fault diagnosis system for an automobile engine according to claim 7, characterized in that, The image analysis unit will determine the maximum value of the first difference. Comparison with the first difference value Compare the two values ​​and take the maximum value of the second difference. Comparison with the second difference value In comparison, among them, Based on the first difference comparison result, the image analysis unit determines that the front end shaft of the engine crankshaft is abnormal; Based on the second difference comparison result, the image analysis unit determines that there is no abnormality in the front end shaft of the engine crankshaft; Based on the third difference comparison result, the image analysis unit determines that the rear end shaft of the engine crankshaft is abnormal; Based on the fourth difference comparison result, the image analysis unit determines that there is no abnormality in the rear end shaft of the engine crankshaft; Wherein, the first difference comparison result is that the maximum value of the first difference is greater than the first difference comparison value; the second difference comparison result is that the maximum value of the first difference is less than or equal to the first difference comparison value; the third difference comparison result is that the maximum value of the second difference is greater than the second difference comparison value; and the fourth difference comparison result is that the maximum value of the second difference is less than or equal to the second difference comparison value. , .

9. The fault diagnosis system for an automobile engine according to claim 8, characterized in that, When the image analysis unit determines that the front or rear end shaft of the engine crankshaft is abnormal, it will set the maximum value of the first difference. Compared with the first anomaly characterization value Compare the two values ​​and take the maximum value of the second difference. Compared with the second anomaly characterization value In comparison, among them, Under the first comparison condition, the image analysis unit determines that the abnormal state of the engine crankshaft front end shaft is the first abnormal state; Under the second comparison condition, the image analysis unit determines that the abnormal state of the engine crankshaft front end shaft is the second abnormal state; Under the third comparison condition, the image analysis unit determines that the abnormal state of the engine crankshaft rear end shaft is the first abnormal state; Under the fourth comparison condition, the image analysis unit determines that the abnormal state of the engine crankshaft rear end shaft is the second abnormal state; Wherein, the first comparison condition is that the maximum value of the first difference is less than or equal to the first anomaly characteristic value; the second comparison condition is that the maximum value of the first difference is greater than the first anomaly characteristic value; the third comparison condition is that the maximum value of the second difference is less than or equal to the second anomaly characteristic value; and the fourth comparison condition is that the maximum value of the second difference is greater than the second anomaly characteristic value, and the first anomaly characteristic value... The second abnormal characterization value .

10. The fault diagnosis system for an automobile engine according to claim 9, characterized in that, Based on the abnormal state determined by the image analysis unit, the fault diagnosis module determines the cause of the fault in the front and rear shafts of the engine crankshaft. If the image analysis unit determines that the front end shaft of the engine crankshaft is in a first abnormal state, then the fault diagnosis module determines that the cause of the fault in the front end shaft of the engine crankshaft is misalignment or friction. If the image analysis unit determines that the front end of the engine crankshaft is in a second abnormal state, then the fault diagnosis module determines that the cause of the fault in the front end of the engine crankshaft is oil film oscillation or cracks. If the image analysis unit determines that the engine crankshaft rear end shaft is in a first abnormal state, then the fault diagnosis module determines that the cause of the engine crankshaft rear end shaft fault is misalignment or friction. If the image analysis unit determines that the engine crankshaft rear end shaft is in a second abnormal state, then the fault diagnosis module determines that the cause of the engine crankshaft rear end shaft failure is oil film oscillation or cracks.

Images