Intelligent production system based on engine cylinder head thermal fatigue detection

Abstract

The invention relates to the technical field of cylinder head production, in particular to an intelligent production system based on engine cylinder head thermal fatigue detection. The thermal fatigue simulation module is used for heating the cylinder head; the detection module is used for detecting the thermal fatigue degree of the cylinder head and comprises an ultrasonic assembly and a temperature measurement assembly used for detecting the temperature of air around the cylinder head and the temperatures of the inner wall and the outer wall of the cylinder head; the control module is used for determining an adjustment mode of ultrasonic detection according to the temperature difference between the temperature of the inner wall and the temperature of the outer wall of the cylinder head, including adjustment of the signal-to-noise ratio of the ultrasonic assembly, or adjustment of the height of the ultrasonic signal according to the electroacoustic efficiency of the ultrasonic signal, or determination of the distance between the ultrasonic assembly and the cylinder head according to the deviation value of the echo signal; and the alternating detection frequency of the ultrasonic assembly is adjusted according to the cylinder head cooling rate. According to the invention, the detection accuracy and stability are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cylinder head production, and particularly to an intelligent production system based on thermal fatigue detection of an engine cylinder head. Background Art

[0002] In the prior art, the cylinder head is a part of the engine. It is installed on the top of the cylinder block, seals the cylinder from the upper part and forms the combustion chamber. The cylinder head often contacts with high-temperature and high-pressure gas, so it bears great thermal load and mechanical load. Conducting thermal fatigue tests on the cylinder head is based on the fatigue damage caused by the generation and release of thermal stress during repeated temperature cycling of the material. In the engine cylinder head, this thermal stress is mainly caused by the temperature difference between the inner and outer surfaces of the cylinder head. When the cylinder head is heated, compressive stress is generated inside it, while tensile stress is generated outside; the opposite occurs during cooling. This repeated temperature cycling and stress change ultimately lead to fatigue damage and crack generation in the cylinder head material. Through thermal fatigue tests, the fatigue life of the cylinder head material under specific temperature cycling conditions can be evaluated, the formation and propagation mechanism of cracks can be revealed, and the improvement and optimization of the cylinder head structure can be guided.

[0003] Chinese Patent Publication No.: CN111521565B discloses a crack opening width detection system and method based on laser ultrasound. The system includes a sample (4) with a crack to be measured, an ultrasonic excitation device (1), a heating device (2), an ultrasonic detection device (3), a signal acquisition device (5), a motion device (6), and a control device (7); the ultrasonic excitation device (1) is used as an ultrasonic signal excitation source for the sample (4) with a crack to be measured; the heating device (2) is used to heat the crack to be measured on the sample (4) to generate thermal stress to close the crack; the ultrasonic detection device (3) is used to receive ultrasonic signals; the signal acquisition device (5) is used to acquire ultrasonic signals and transmit them to the control device (7); the motion device (6) is used to drive the heating device (2) to move synchronously with the heating point on the crack to be measured and the crack to be measured; the control device (7) is used to adjust the heating power of the heating device (2) and control the movement of the motion device (6), and is also used to obtain the opening width of the crack to be measured on the sample (4) according to the correspondence between the displacement generated by crack closure and the heating power; the excitation point where the ultrasonic excitation device (1) irradiates the surface of the sample (4), the heating point where the heating device (2) irradiates the crack to be measured, and the detection point where the ultrasonic detection device (3) performs ultrasonic detection are located on the same straight line, and this straight line is perpendicular to the direction of the crack to be measured. Thus, in the above crack opening width detection system and method based on laser ultrasound, there are problems that in thermal fatigue detection, ultrasonic detection encounters high-temperature gas, which will cause the sound wave propagation speed to change, thereby resulting in a decrease in detection accuracy, and due to the appearance of temperature gradients in the detection environment, the sound wave encounters air layers with different temperatures during propagation, thereby changing its propagation speed, direction, and even causing attenuation of the sound wave intensity and distortion of the phase. Summary of the Invention

[0004] Therefore, the present invention provides an intelligent production system for engine cylinder head thermal fatigue detection to overcome the problems in the prior art that in thermal fatigue detection, ultrasonic detection encounters high-temperature gas, which will cause the sound wave propagation speed to change, thereby resulting in a decrease in detection accuracy, and due to the appearance of temperature gradients in the detection environment, the sound wave encounters air layers with different temperatures during propagation, thereby changing its propagation speed, direction, and even causing attenuation of the sound wave intensity and distortion of the phase.

[0005] To achieve the above object, the present invention provides an intelligent production system for engine cylinder head thermal fatigue detection, including a box body, and further including:

[0006] A production module for outputting a cylinder head;

[0007] A thermal fatigue simulation module, which is arranged at the inner bottom of the box body and simulates the thermal fatigue process of the cylinder head by heating the cylinder head output by the production module;

[0008] A detection module, which is connected to the thermal fatigue simulation module and is used to detect the thermal fatigue degree of the cylinder head, including an ultrasonic component for ultrasonic detection of the cylinder head to determine whether cracks occur in the cylinder head and a temperature measurement component partially connected to the cylinder head for detecting the air temperature around the cylinder head and the temperature parameters of the cylinder head;

[0009] A control module, which is respectively connected to the thermal fatigue simulation module and the detection module, and is used to determine the adjustment method of ultrasonic detection according to the temperature difference between the inner and outer wall temperatures of the cylinder head, including adjusting the signal-to-noise ratio of the ultrasonic component,

[0010] or, adjusting the height of the ultrasonic signal according to the electro-acoustic efficiency of the ultrasonic signal,

[0011] or, determining the distance between the ultrasonic component and the cylinder head according to the deviation amount of the echo signal, and adjusting the alternating detection frequency of the ultrasonic component according to the cylinder head cooling rate.

[0012] Further, the ultrasonic component includes:

[0013] A first ultrasonic transmitter, which is arranged inside the box body;

[0014] A second ultrasonic transmitter, which is arranged parallel to the rear of the first ultrasonic transmitter;

[0015] A first slider type telescopic rod, which is connected to the first ultrasonic transmitter and is used to adjust the distance between the first ultrasonic transmitter and the cylinder head and the height between the first ultrasonic transmitter and the lower surface of the box body;

[0016] A second slider type telescopic rod, which is connected to the second ultrasonic transmitter and is used to adjust the distance between the second ultrasonic transmitter and the cylinder head and the height between the second ultrasonic transmitter and the lower surface of the box body;

[0017] Wherein, the heights of the first ultrasonic transmitter and the second ultrasonic transmitter are equal to the height of the cylinder head.

[0018] Further, the temperature measurement component includes:

[0019] A first temperature sensor, which is arranged on the inner wall of the cylinder head and is used to detect the inner wall temperature of the cylinder head;

[0020] A second temperature sensor, which is arranged on the outer wall of the cylinder head and is used to detect the outer wall temperature of the cylinder head;

[0021] An infrared thermal imaging thermometer, which is arranged above the second temperature sensor and is used to detect the air temperature between the first ultrasonic transmitter and the second ultrasonic transmitter and the cylinder head respectively.

[0022] Further, the control module is respectively connected to the temperature measurement component and the ultrasonic component, and is used to obtain the change rate of the temperature difference between the inner and outer walls of the cylinder head in the first detection stage.

[0023] If the change rate of the temperature difference is greater than a preset second change rate, it is determined that the accuracy of the ultrasonic detection does not meet the requirements, and the signal-to-noise ratios of the first ultrasonic transmitter and the second ultrasonic transmitter are respectively reduced.

[0024] Further, the signal-to-noise ratio is negatively correlated with the change rate of the temperature difference; the change rate of the temperature difference is the ratio of the difference between the inner wall temperature and the outer wall temperature of the cylinder head to the unit detection time of the thermal fatigue simulation operation cycle.

[0025] Further, the control module is connected to the ultrasonic component, and is used to preliminarily determine that the stability of signal transmission does not meet the requirements under the condition that the change rate of the temperature difference is greater than a preset first change rate and less than or equal to the preset second change rate, and obtain the electro-acoustic efficiency of the ultrasonic signal of the ultrasonic component. Among them,

[0026] If the electro-acoustic efficiency is less than a preset first electro-acoustic efficiency, it is secondarily determined that the stability of signal transmission does not meet the requirements, and the heights of the first ultrasonic transmitter and the second ultrasonic transmitter are respectively increased.

[0027] Among them, the height is negatively correlated with the electro-acoustic efficiency.

[0028] Further, the control module is respectively connected to the ultrasonic component and the infrared thermal imaging temperature measuring instrument, and is used to preliminarily determine that the emission stability of the ultrasonic signal does not meet the requirements under the condition that the electro-acoustic efficiency is greater than or equal to the preset first electro-acoustic efficiency and less than the preset second electro-acoustic efficiency, and calculate the deviation amount of the echo signals of the first ultrasonic transmitter and the second ultrasonic transmitter.

[0029] If the deviation amount is greater than a preset deviation amount, it is secondarily determined that the emission stability of the ultrasonic signal does not meet the requirements, and the distances between the first ultrasonic transmitter and the second ultrasonic transmitter and the cylinder head are respectively reduced to positions that meet the detection temperature conditions.

[0030] Further, the deviation amount of the echo signal is the absolute value of the difference between the peak sound pressures of the echo signal of the first ultrasonic transmitter after the heating of the thermal fatigue simulation module stops and the echo signal of the second ultrasonic transmitter after the heating of the thermal fatigue simulation module stops.

[0031] The detected temperature condition is the end position of the unit length when the air temperature difference is the maximum value among the air temperature differences of several unit lengths of the straight-line distances between the first ultrasonic transmitter and the second ultrasonic transmitter and the cylinder head respectively;

[0032] The air temperature difference of the unit length is the difference between the air temperature at the end position of the unit length and the air temperature at the starting position of the unit length.

[0033] Further, the control module is connected to the temperature measurement component to obtain the cooling rate of the inner wall of the cylinder head after the heat fatigue simulation module stops heating. If the cooling rate is greater than the preset cooling rate, it is determined that the stability of the echo signal does not meet the requirements, and the alternating detection frequency of the first ultrasonic transmitter and the second ultrasonic transmitter is increased.

[0034] Further, the alternating detection frequency is the number of alternating detections of the first ultrasonic transmitter and the second ultrasonic transmitter within a unit detection time; the alternating detection frequency is positively correlated with the cooling rate.

[0035] Compared with the prior art, the beneficial effects of the present invention are that the system of the present invention is provided with a heat fatigue simulation module, a detection module and a control module. Since the temperature of the cylinder head is increased, kept constant and decreased during the heat fatigue test of the cylinder head, the effects on ultrasonic detection are different. By analyzing the detection state and adjusting the detection parameters of the ultrasonic transmitter in real time, the accuracy and stability of ultrasonic detection during the heat fatigue detection of the cylinder head are ensured; when the cylinder head is heated and the temperature is increased, due to the fast heating rate, the temperature difference between the inside and outside of the cylinder head is too large, which in turn leads to the propagation speed of ultrasonic waves in the medium. By adjusting the signal-to-noise ratio of the ultrasonic component, the influence of the too large temperature difference on the accuracy of ultrasonic detection is reduced; after the temperature of the cylinder head is stable, the cylinder head transfers heat to other areas in the box, resulting in a temperature difference in the detection space. The temperature difference causes the propagation speed and direction of sound waves, and even causes the attenuation of sound wave intensity and the distortion of phase, and the temperature difference at high temperature increases the detection error. By adjusting the distance between the ultrasonic component and the cylinder head, the error expansion caused by the change of sound wave propagation direction and intensity attenuation caused by the temperature difference is reduced; during the high-temperature heat fatigue test process, stress changes may cause the stability of the ultrasonic signal echo to decline, and the deviation of the ultrasonic echo signal will gradually decrease. By adjusting the alternating detection frequency, the noise interference is reduced, and the accuracy and stability of heat fatigue detection are improved.

[0036] Furthermore, by setting a first ultrasonic transmitter, a second ultrasonic transmitter, a first slider-type telescopic rod, and a second slider-type telescopic rod, the system of the present invention can achieve comprehensive detection of different positions of the cylinder head, ensuring the accuracy and reliability of the detection. The first ultrasonic transmitter and the second ultrasonic transmitter can detect whether there are cracks inside the cylinder head by emitting ultrasonic waves to the cylinder head, thereby evaluating the thermal fatigue degree of the cylinder head; the first slider-type telescopic rod and the second slider-type telescopic rod can adjust the distance and height between the ultrasonic transmitter and the cylinder head to adapt to the sizes and shapes of different cylinder heads, achieving an improvement in the flexibility and applicability of the detection.

[0037] Furthermore, by setting a first temperature sensor, a second temperature sensor, and an infrared thermal imaging thermometer, the system of the present invention can monitor the temperatures of the inner and outer walls of the cylinder head and the air temperature between the ultrasonic transmitter and the cylinder head in real time, thereby obtaining temperature change information during the thermal fatigue detection of the cylinder head. The first temperature sensor is arranged on the inner wall of the cylinder head and is used to accurately measure the temperature of the inner wall of the cylinder head, reflecting the internal state of the cylinder head. The second temperature sensor is arranged on the outer wall of the cylinder head and is used to measure the temperature of the outer wall of the cylinder head, forming a comparison with the inner wall temperature to help analyze the thermal stress distribution of the cylinder head; the infrared thermal imaging thermometer uses infrared thermal imaging technology to non-contact measure the air temperature between the ultrasonic transmitter and the cylinder head, providing an environmental temperature reference for ultrasonic detection and helping to judge the working environment of ultrasonic detection, achieving an improvement in the accuracy of ultrasonic detection.

[0038] Furthermore, by setting a preset second change rate, when the change rate is large, it indicates that the heating rate in the cavity of the cylinder head increases. During the propagation of the ultrasonic signal, it may be affected by factors such as the thermal expansion of the cylinder head material. At this time, the internal temperature of the cylinder head changes violently, resulting in stress changes in the cylinder head, and the propagation rate of the ultrasonic wave increases due to the influence of temperature. Therefore, by reducing the signal-to-noise ratio of the ultrasonic transmitter, the false detection rate can be reduced, achieving an improvement in the accuracy of the detection result.

[0039] Furthermore, by setting a preset first electro-acoustic efficiency and a preset second electro-acoustic efficiency, the temperature inside the box increases due to the heat conduction of the cylinder head. When the temperature rises, the resistance of the transmission line of the ultrasonic transmitter increases, and the electro-acoustic efficiency of the ultrasonic wave signal will decrease. If the electro-acoustic efficiency is lower than the preset first electro-acoustic efficiency, it indicates that the stability of signal transmission may be affected. Therefore, by increasing the height of the ultrasonic transmitter, that is, reducing the bending of the transmission line, the line resistance can be reduced, thereby improving the electro-acoustic efficiency of the ultrasonic wave signal, achieving an improvement in the stability of signal transmission.

[0040] Furthermore, in the system of the present invention, by setting a deviation amount, since the temperature is raised and lowered during the thermal fatigue detection process, which causes deviations in the ultrasonic device, the detection results of the two ultrasonic transmitters are mutually authenticated to determine whether the transmitter is fatigued and damaged due to frequent temperature rises and falls in the environment. When the deviation amount exceeds the normal range, it indicates that there may be a large error in the detection result of the ultrasonic transmitter. Since the cylinder head dissipates heat to the surrounding environment, a certain temperature gradient will be generated in the detection space, and the error range increases under the influence of the temperature gradient. By reducing the distance between the ultrasonic transmitter and the cylinder head, the influence of the air temperature difference on the sound wave propagation is reduced, thereby improving the accuracy of ultrasonic detection.

[0041] Furthermore, in the system of the present invention, by setting a cooling rate, since the ultrasonic propagation rate decreases after the cylinder head dissipates heat to the air and then connects to the cooling, and the stress of the cylinder head is released. During the cooling process of the cylinder head, cracks may be generated or expanded due to the shrinkage of the cylinder head material. At this time, the control module increases the alternating detection frequency of the ultrasonic transmitter to more accurately capture the dynamic changes of the cracks. If the cooling rate is too large, it may lead to a decrease in the stability of the ultrasonic signal echo. By increasing the alternating detection frequency, that is, increasing the detection frequency of the ultrasonic transmitter, the signal-to-noise ratio of the ultrasonic signal is improved, thereby improving the accuracy and stability of thermal fatigue detection. Description of the Drawings

[0042] Figure 1 It is a schematic structural diagram of an intelligent production system for thermal fatigue detection of an engine cylinder head according to an embodiment of the present invention;

[0043] Figure 2 It is a top view structural diagram of an intelligent production system for thermal fatigue detection of an engine cylinder head according to an embodiment of the present invention;

[0044] Figure 3 It is a structural block diagram of an intelligent production system for thermal fatigue detection of an engine cylinder head according to an embodiment of the present invention;

[0045] Figure 4 It is a structural block diagram of a temperature measurement component of an intelligent production system for thermal fatigue detection of an engine cylinder head according to an embodiment of the present invention;

[0046] Explanation of the reference numerals in the drawings: 1 - box body, 2 - first ultrasonic transmitter, 3 - first slider type telescopic rod, 4 - first slide rail, 5 - lifting rod, 6 - high-frequency induction heater, 7 - second temperature sensor, 8 - cylinder head, 9 - infrared thermal imaging temperature measuring instrument, 10 - second ultrasonic transmitter, 11 - second slide rail. Detailed Embodiments

[0047] In order to make the objectives and advantages of the present invention more clearly understood, the present invention will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0048] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and do not limit the protection scope of the present invention.

[0049] It should be noted that in the description of the present invention, the terms indicating the direction or positional relationship such as "upper", "lower", "left", "right", "inner", "outer", etc. are based on the direction or positional relationship shown in the drawings. This is only for convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0050] In addition, it should also be noted that in the description of the present invention, unless otherwise clearly specified and defined, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0051] Please refer to Figure 1 、 Figure 2 、 Figure 3 and Figure 4 as shown, which are respectively the structural schematic diagram; the top view structural schematic diagram; the structural block diagram and the temperature measurement component block diagram of the intelligent production system based on the thermal fatigue detection of the engine cylinder head in the embodiment of the present invention. An intelligent production system based on the thermal fatigue detection of the engine cylinder head in an embodiment of the present invention includes a box body and further includes:

[0052] A production module for outputting a cylinder head;

[0053] A thermal fatigue simulation module, which is arranged at the inner bottom of the box body and simulates the thermal fatigue process of the cylinder head by heating the cylinder head output by the production module;

[0054] A detection module, which is connected to the thermal fatigue simulation module and is used to detect the thermal fatigue degree of the cylinder head, including an ultrasonic component for ultrasonic detection of the cylinder head to determine whether cracks occur in the cylinder head and a temperature measurement component partially connected to the cylinder head for detecting the air temperature around the cylinder head and the temperature parameters of the cylinder head;

[0055] A control module, which is respectively connected to the thermal fatigue simulation module and the detection module, and is used to determine the adjustment method of ultrasonic detection according to the temperature difference between the inner and outer walls of the cylinder head, including adjusting the signal-to-noise ratio of the ultrasonic component,

[0056] or, adjusting the height of the ultrasonic signal according to the electro-acoustic efficiency of the ultrasonic signal,

[0057] or, determining the distance between the ultrasonic component and the cylinder head according to the deviation amount of the echo signal, and adjusting the alternating detection frequency of the ultrasonic component according to the cooling rate of the cylinder head.

[0058] Specifically, the thermal fatigue simulation module includes:

[0059] A high-frequency induction heater, which heats the cylinder head by generating eddy currents;

[0060] A lifting rod, which is connected to the high-frequency induction heater and is used to adjust the height of the high-frequency induction heater;

[0061] A lifting motor, which is connected to the lifting rod and provides driving force for the lifting rod.

[0062] Specifically, the cylinder head is sleeved outside the electric coil of the high-frequency induction heater.

[0063] Specifically, the detection module is used to judge whether the degree of thermal fatigue meets the requirements according to whether there are cracks in the cylinder head. If there are cracks, it does not meet the requirements.

[0064] In practice, the beneficial effect of the present invention is that the system of the present invention is provided with a thermal fatigue simulation module, a detection module and a control module. Since the temperature of the cylinder head is increased, kept constant, and decreased during the thermal fatigue test of the cylinder head, the influence on ultrasonic detection is different. By analyzing the detection state and adjusting the detection parameters of the ultrasonic transmitter in real time, the accuracy and stability of ultrasonic detection during the thermal fatigue detection of the cylinder head are ensured; when heating and raising the temperature of the cylinder head, since the heating rate is fast, the temperature difference between the inside and outside of the cylinder head is too large, which in turn leads to the propagation speed of ultrasonic waves in the medium. By adjusting the signal-to-noise ratio of the ultrasonic component, the influence of the too large temperature difference on the accuracy of ultrasonic detection is reduced; after the temperature of the cylinder head is stable, the cylinder head transfers heat to other areas in the box, resulting in a temperature difference in the detection space. The temperature difference causes the propagation speed and direction of sound waves, and even causes attenuation of sound wave intensity and distortion of phase, and the temperature difference at high temperature increases the detection error. By adjusting the distance between the ultrasonic component and the cylinder head, the error caused by the change in the propagation direction of sound waves and the attenuation of intensity caused by the temperature difference is reduced; during the high-temperature thermal fatigue test, stress changes may lead to a decrease in the stability of the ultrasonic signal echo, and the deviation of the ultrasonic echo signal will gradually decrease. By adjusting the alternating detection frequency, noise interference is reduced, and the accuracy and stability of thermal fatigue detection are improved.

[0065] Specifically, the ultrasonic component includes:

[0066] A first ultrasonic transmitter, which is arranged inside the box body;

[0067] A second ultrasonic transmitter, which is arranged in parallel behind the first ultrasonic transmitter;

[0068] A first slider type telescopic rod, which is connected to the first ultrasonic transmitter and is used to adjust the distance between the first ultrasonic transmitter and the cylinder head and the height between the first ultrasonic transmitter and the lower surface of the box body;

[0069] A second slider type telescopic rod, which is connected to the second ultrasonic transmitter and is used to adjust the distance between the second ultrasonic transmitter and the cylinder head and the height between the second ultrasonic transmitter and the lower surface of the box body;

[0070] Wherein, the heights of the first ultrasonic transmitter and the second ultrasonic transmitter are equal to the height of the cylinder head.

[0071] Specifically, the heights of the first slider type telescopic rod and the second slider type telescopic rod are adjusted by a first telescopic motor and a second telescopic motor respectively connected thereto.

[0072] Specifically, the ultrasonic component further includes:

[0073] A first slide rail, which is connected to the first slider type telescopic rod and is used to define the horizontal translation position of the first ultrasonic transmitter;

[0074] A second slide rail, which is connected to the second slider type telescopic rod and is used to define the horizontal translation position of the second ultrasonic transmitter;

[0075] A first moving motor, which is connected to the first slide rail and is used to provide driving force for the first slider type telescopic rod to translate on the first slide rail;

[0076] A second moving motor, which is connected to the second slide rail and is used to provide driving force for the second slider type telescopic rod to translate on the second slide rail;

[0077] A first ultrasonic receiver, which is arranged on the inner wall of the box body and is used to receive the ultrasonic signal emitted by the first ultrasonic transmitter;

[0078] A second ultrasonic receiver, which is arranged on the inner wall of the box body and is used to receive the ultrasonic signal emitted by the second ultrasonic transmitter.

[0079] Specifically, the first ultrasonic receiver and the second ultrasonic receiver calculate whether a crack occurs according to the change in the ultrasonic wave speed and the return time.

[0080] Specifically, the lifting motor, the first telescopic motor, and the second telescopic motor are in a linked state.

[0081] Specifically, the detection methods of the first ultrasonic transmitter and the second ultrasonic transmitter are continuous alternating detections.

[0082] In implementation, the system of the present invention can achieve comprehensive detection of different positions of the cylinder head by setting the first ultrasonic transmitter, the second ultrasonic transmitter, the first sliding telescopic rod, and the second sliding telescopic rod, ensuring the accuracy and reliability of the detection. The first ultrasonic transmitter and the second ultrasonic transmitter can detect whether there are cracks inside the cylinder head by emitting ultrasonic waves to the cylinder head, thereby evaluating the thermal fatigue degree of the cylinder head; the first sliding telescopic rod and the second sliding telescopic rod can adjust the distance and height between the ultrasonic transmitter and the cylinder head to adapt to the sizes and shapes of different cylinder heads, improving the flexibility and applicability of the detection.

[0083] Specifically, the temperature measurement component includes:

[0084] A first temperature sensor, which is arranged on the inner wall of the cylinder head for detecting the inner wall temperature of the cylinder head;

[0085] A second temperature sensor, which is arranged on the outer wall of the cylinder head for detecting the outer wall temperature of the cylinder head;

[0086] An infrared thermal imaging thermometer, which is arranged above the second temperature sensor for detecting the air temperature between the first ultrasonic transmitter and the second ultrasonic transmitter and the cylinder head respectively.

[0087] Specifically, the first temperature sensor and the second temperature sensor are contact type temperature sensors.

[0088] In implementation, the system of the present invention can monitor the inner and outer wall temperatures of the cylinder head and the air temperature between the ultrasonic transmitter and the cylinder head in real time by setting the first temperature sensor, the second temperature sensor, and the infrared thermal imaging thermometer, thereby obtaining the temperature change information during the thermal fatigue detection of the cylinder head. The first temperature sensor is arranged on the inner wall of the cylinder head for accurately measuring the inner wall temperature of the cylinder head and reflecting the internal state of the cylinder head. The second temperature sensor is arranged on the outer wall of the cylinder head for measuring the outer wall temperature of the cylinder head and forming a comparison with the inner wall temperature to help analyze the thermal stress distribution of the cylinder head; the infrared thermal imaging thermometer uses infrared thermal imaging technology to non-contact measure the air temperature between the ultrasonic transmitter and the cylinder head, providing an environmental temperature reference for ultrasonic detection and helping to judge the working environment of ultrasonic detection, improving the accuracy of ultrasonic detection.

[0089] Specifically, the control module is respectively connected to the temperature measurement component and the ultrasonic component for obtaining the rate of change of the temperature difference between the inner and outer wall temperatures of the cylinder head in the first detection stage,

[0090] If the change rate of the temperature difference is greater than a preset second change rate, it is determined that the accuracy of the ultrasonic detection does not meet the requirements, and the signal-to-noise ratios of the first ultrasonic transmitter and the second ultrasonic transmitter are respectively reduced.

[0091] Specifically, the maximum heating temperature of the cylinder head by the thermal fatigue simulation module is the operating temperature after the engine starts. When the cylinder head for testing is the cylinder head of a small car engine, the general value range of the preset temperature is [450 °C, 750 °C], and the preferred embodiment is 600 °C.

[0092] Specifically, the signal-to-noise ratio is negatively correlated with the change rate of the temperature difference; the change rate of the temperature difference is the ratio of the difference between the inner wall temperature and the outer wall temperature of the cylinder head to the unit detection time of the thermal fatigue simulation operation cycle.

[0093] Specifically, the general value range of the preset first change rate is [18 °C / min, 24 °C / min], and the preferred embodiment of the preset first change rate is 20 °C / min; the general value range of the preset second change rate is [26 °C / min, 35 °C / min], and the preferred embodiment of the preset second change rate is 30 °C / min.

[0094] In implementation, when the difference between the change rate of the temperature difference and the preset second change rate is within 1 °C / min, the signal-to-noise ratio is reduced by 0.01 dB. When the difference between the change rate of the temperature difference and the preset second change rate exceeds 1 °C / min, for every 1 °C / min exceeded, the signal-to-noise ratio is reduced by 0.01 dB. For example, when the change rate of the temperature difference is 35 °C / min, the current signal-to-noise ratio is 0.4 dB, and the signal-to-noise ratio is reduced to 0.4 dB - 0.1 dB × 5 = 0.35 dB.

[0095] In implementation, by setting the preset second change rate in the system of the present invention, when the change rate is large, it indicates that the heating rate in the cavity of the cylinder head increases. The ultrasonic signal may be affected by factors such as the thermal expansion of the cylinder head material during propagation. At this time, the internal temperature of the cylinder head changes violently, resulting in a change in the stress of the cylinder head, and the propagation rate of the ultrasonic wave increases due to the influence of temperature. Therefore, by reducing the signal-to-noise ratio of the ultrasonic transmitter, the false detection rate can be reduced, and the accuracy of the detection result is improved.

[0096] Specifically, the control module is connected to the ultrasonic component to preliminarily determine that the stability of signal transmission does not meet the requirements under the condition that the change rate of the temperature difference is greater than the preset first change rate and less than or equal to the preset second change rate, and obtain the electro-acoustic efficiency of the ultrasonic signal of the ultrasonic component, where

[0097] If the electro-acoustic efficiency is less than the preset first electro-acoustic efficiency, the stability of the secondary determination signal transmission does not meet the requirements, and the heights of the first ultrasonic transmitter and the second ultrasonic transmitter are increased respectively.

[0098] Among them, the height is negatively correlated with the electro-acoustic efficiency.

[0099] Specifically, the electro-acoustic efficiency of the ultrasonic signal is the efficiency of converting the mechanical energy of the ultrasonic transmitter into sound energy; the electro-acoustic efficiency is detected by a power tester connected to the first ultrasonic transmitter and the second ultrasonic transmitter respectively.

[0100] Specifically, the general value range of the preset first electro-acoustic efficiency is [88%, 92%], and the general value range of the preset second electro-acoustic efficiency is [93%, 95%].

[0101] Preferably, the preferred embodiment of the preset first electro-acoustic efficiency is 90%, and the preferred embodiment of the preset second electro-acoustic efficiency is 94%.

[0102] In implementation, when the difference between the preset first electro-acoustic efficiency and the electro-acoustic efficiency is within 1%, the height of the ultrasonic transmitter is increased by 3 cm. For every 1% that the difference between the preset first electro-acoustic efficiency and the electro-acoustic efficiency exceeds, the height is increased by 1 cm. For example, if the electro-acoustic efficiency is 88% and the current height is 14 cm, then the height increase is 14 cm + 3 cm + 1 cm = 18 cm.

[0103] In implementation, in the system of the present invention, by setting the preset first electro-acoustic efficiency and the preset second electro-acoustic efficiency, the temperature inside the box increases through the heat conduction of the cylinder head. When the temperature rises, the line resistance of the transmission line of the ultrasonic transmitter increases, and the electro-acoustic efficiency of the ultrasonic wave signal will decrease. If the electro-acoustic efficiency is lower than the preset first electro-acoustic efficiency, it indicates that the stability of the signal transmission may be affected. Therefore, by increasing the height of the ultrasonic transmitter, that is, reducing the bending of the transmission line, the line resistance is reduced, thereby increasing the electro-acoustic efficiency of the ultrasonic wave signal and realizing the improvement of the signal transmission stability.

[0104] Specifically, the control module is respectively connected to the ultrasonic component and the infrared thermal imaging temperature measuring instrument, and is used to initially determine that the emission stability of the ultrasonic signal does not meet the requirements under the condition that the electro-acoustic efficiency is greater than or equal to the preset first electro-acoustic efficiency and less than the preset second electro-acoustic efficiency, and calculate the deviation amount of the echo signals of the first ultrasonic transmitter and the second ultrasonic transmitter.

[0105] If the deviation amount is greater than the preset deviation amount, it is secondarily determined that the emission stability of the ultrasonic signal does not meet the requirements, and the distances between the first ultrasonic transmitter and the second ultrasonic transmitter and the cylinder head are respectively reduced to positions that meet the detection temperature conditions.

[0106] Specifically, the deviation amount of the echo signal is the absolute value of the difference between the peak sound pressure of the echo signal of the first ultrasonic transmitter after the heat fatigue simulation module stops heating and the peak sound pressure of the echo signal of the second ultrasonic transmitter after the heat fatigue simulation module stops heating;

[0107] The detected temperature condition is the end position of the unit length when the air temperature difference is the maximum among the air temperature differences of several unit lengths of the linear distances between the first ultrasonic transmitter and the second ultrasonic transmitter and the cylinder head respectively;

[0108] The air temperature difference of the unit length is the difference between the air temperature at the end position of the unit length and the air temperature at the starting position of the unit length.

[0109] Specifically, the general value range of the preset deviation amount is [0.4 Pa, 1 Pa], and the preferred embodiment of the preset deviation amount is 0.6 Pa.

[0110] In practice, further, in the system of the present invention, by setting the deviation amount, since the ultrasonic device has a deviation during the process of heat fatigue detection due to heating and cooling, the detection results of the two ultrasonic transmitters are mutually authenticated to determine whether the transmitter is fatigued and damaged due to frequent heating and cooling of the ambient temperature. When the deviation amount exceeds the normal range, it indicates that there may be a large error in the detection result of the ultrasonic transmitter. Since the cylinder head dissipates heat to the surrounding environment, a certain temperature gradient will be generated in the detection space, and the error range increases under the influence of the temperature gradient. By reducing the distance between the ultrasonic transmitter and the cylinder head, the influence of the air temperature difference on the sound wave propagation is reduced, and the accuracy of ultrasonic detection is improved.

[0111] Specifically, the control module is connected to the temperature measurement component to obtain the cooling rate of the inner wall of the cylinder head after the heat fatigue simulation module stops heating. If the cooling rate is greater than the preset cooling rate, it is determined that the stability of the echo signal does not meet the requirements, and the alternating detection frequency of the first ultrasonic transmitter and the second ultrasonic transmitter is increased.

[0112] Specifically, the alternating detection frequency is the number of alternating detections of the first ultrasonic transmitter and the second ultrasonic transmitter within the unit detection time; the alternating detection frequency is positively correlated with the cooling rate.

[0113] Specifically, the cooling rate is the descending rate of the temperature of the inner wall of the cylinder head within the unit temperature monitoring time after the high-frequency induction heater stops working.

[0114] Specifically, the general value range of the preset cooling rate is [18 °C / min, 24 °C / min].

[0115] Preferably, a preferred embodiment of the preset first cooling rate is 20 °C / min.

[0116] In implementation, when the difference between the cooling rate and the preset cooling rate is within 1 °C / min, the alternating detection frequency increases by 2 times / min. When the difference between the cooling rate and the preset cooling rate exceeds 1 °C / min, for every 1 °C / min exceeded, the alternating detection frequency increases by 1 time / min. For example, if the cooling rate is 36 °C / min and the current alternating detection frequency is 12 times / min, the alternating detection frequency increases to 12 times / min + 2 times / min + 1 time / min = 15 times / min.

[0117] In implementation, in the system of the present invention, by setting the cooling rate, since the ultrasonic propagation rate decreases after the cylinder head dissipates heat to the air and then is connected for cooling, and the stress of the cylinder head is released. During the cooling process of the cylinder head, cracks may be generated or extended due to the shrinkage of the cylinder head material. At this time, the control module increases the alternating detection frequency of the ultrasonic transmitter to more accurately capture the dynamic changes of the cracks. If the cooling rate is too large, it may lead to a decrease in the stability of the ultrasonic signal echo. By increasing the alternating detection frequency, that is, increasing the detection frequency of the ultrasonic transmitter, the signal-to-noise ratio of the ultrasonic signal is improved, and the accuracy and stability of the thermal fatigue detection are improved.

[0118] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle 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 fall within the protection scope of the present invention.

Claims

1. An intelligent production system based on thermal fatigue detection of engine cylinder heads, comprising a box, characterized in that: Also includes: Production module for outputting cylinder heads; A thermal fatigue simulation module, which is arranged at the inner bottom of the box, and simulates the thermal fatigue process of the cylinder head by heating the cylinder head output by the production module; a detection module connected to the thermal fatigue simulation module and used to detect the thermal fatigue degree of the cylinder head, including an ultrasonic component for performing ultrasonic detection on the cylinder head to determine whether cracks occur in the cylinder head and a temperature measurement component partially connected to the cylinder head and used to detect the air temperature around the cylinder head and the temperature parameters of the cylinder head; A control module, which is connected to the thermal fatigue simulation module and the detection module respectively, is used to determine the adjustment mode of the ultrasonic detection according to the temperature difference between the inner and outer wall temperatures of the cylinder head, including adjusting the signal-to-noise ratio of the ultrasonic component, Or, adjusting the height of the ultrasonic signal according to the electroacoustic efficiency of the ultrasonic signal, Alternatively, the distance between the ultrasonic component and the cylinder head is determined according to the deviation of the echo signal, and the alternating detection frequency of the ultrasonic component is adjusted according to the cooling rate of the cylinder head.

2. The intelligent production system based on engine cylinder head thermal fatigue detection according to claim 1 is characterized in that: The ultrasonic assembly comprises: A first ultrasonic transmitter, which is arranged inside the box; A second ultrasonic transmitter, which is arranged in parallel behind the first ultrasonic transmitter; A first slider-type telescopic rod, which is connected to the first ultrasonic transmitter and is used to adjust the distance between the first ultrasonic transmitter and the cylinder head and the height between the first ultrasonic transmitter and the lower surface of the box body; a second slider-type telescopic rod, connected to the second ultrasonic transmitter, for adjusting the distance between the second ultrasonic transmitter and the cylinder head and the height between the second ultrasonic transmitter and the lower surface of the box body; Wherein, the heights of the first ultrasonic transmitter and the second ultrasonic transmitter are equal to the height of the cylinder head.

3. The intelligent production system based on engine cylinder head thermal fatigue detection according to claim 2 is characterized in that: The temperature measuring component comprises: A first temperature sensor, which is arranged on the inner wall of the cylinder head and is used to detect the inner wall temperature of the cylinder head; A second temperature sensor is arranged on the outer wall of the cylinder head to detect the temperature of the outer wall of the cylinder head; An infrared thermal imaging thermometer is arranged above the second temperature sensor to detect the air temperature between the first ultrasonic transmitter and the second ultrasonic transmitter and the cylinder head respectively.

4. The intelligent production system based on engine cylinder head thermal fatigue detection according to claim 3 is characterized in that: The control module is connected to the temperature measuring component and the ultrasonic component respectively, so as to obtain the temperature difference change rate of the inner and outer wall temperatures of the cylinder head in the first detection stage. If the temperature difference change rate is greater than a preset second change rate, it is determined that the accuracy of the ultrasonic detection does not meet the requirements, and the signal-to-noise ratio of the first ultrasonic transmitter and the second ultrasonic transmitter are reduced respectively.

5. The intelligent production system based on engine cylinder head thermal fatigue detection according to claim 4 is characterized in that: The signal-to-noise ratio is negatively correlated with the temperature difference change rate; the temperature difference change rate is the ratio of the difference between the inner wall temperature and the outer wall temperature of the cylinder head to the unit detection time of the thermal fatigue simulation operation cycle.

6. The intelligent production system based on engine cylinder head thermal fatigue detection according to claim 5 is characterized in that: The control module is connected to the ultrasonic component, and is used to preliminarily determine that the stability of signal transmission does not meet the requirements under the condition that the temperature difference change rate is greater than the preset first change rate and less than or equal to the preset second change rate, and obtain the electroacoustic efficiency of the ultrasonic signal of the ultrasonic component, wherein, If the electroacoustic efficiency is less than the preset first electroacoustic efficiency, the stability of the secondary determination signal transmission does not meet the requirements, and the heights of the first ultrasonic transmitter and the second ultrasonic transmitter are increased respectively. Wherein, the height is negatively correlated with the electroacoustic efficiency.

7. The intelligent production system based on engine cylinder head thermal fatigue detection according to claim 6 is characterized in that: The control module is connected to the ultrasonic component and the infrared thermal imaging thermometer respectively, and is used to preliminarily determine that the emission stability of the ultrasonic signal does not meet the requirements under the condition that the electroacoustic efficiency is greater than or equal to the preset first electroacoustic efficiency and less than the preset second electroacoustic efficiency, and calculate the deviation amount of the echo signal of the first ultrasonic transmitter and the second ultrasonic transmitter, If the deviation is greater than a preset deviation, it is determined that the emission stability of the ultrasonic signal does not meet the requirement for the second time, and the distances between the first ultrasonic transmitter and the second ultrasonic transmitter and the cylinder head are respectively reduced to positions that meet the detection temperature conditions.

8. The intelligent production system based on engine cylinder head thermal fatigue detection according to claim 7 is characterized in that: The deviation of the echo signal is the absolute value of the difference between the peak sound pressure of the echo signal of the first ultrasonic transmitter after the thermal fatigue simulation module stops heating and the peak sound pressure of the echo signal of the second ultrasonic transmitter after the thermal fatigue simulation module stops heating; The detection temperature condition is the end position per unit length when the air temperature difference is the maximum value among the air temperature differences per unit length of the straight-line distance between the first ultrasonic transmitter and the second ultrasonic transmitter and the cylinder head respectively; The air temperature difference per unit length is the difference between the air temperature at the end position of the unit length and the air temperature at the start position of the unit length.

9. The intelligent production system based on engine cylinder head thermal fatigue detection according to claim 8 is characterized in that: The control module is connected to the temperature measuring component to obtain the cooling rate of the inner wall of the cylinder head after the thermal fatigue simulation module stops heating. If the cooling rate is greater than the preset cooling rate, it is determined that the stability of the echo signal does not meet the requirements, and the alternating detection frequency of the first ultrasonic transmitter and the second ultrasonic transmitter is increased.

10. The intelligent production system based on engine cylinder head thermal fatigue detection according to claim 9 is characterized in that: The alternating detection frequency is the number of alternating detections of the first ultrasonic transmitter and the second ultrasonic transmitter within a unit detection time; the alternating detection frequency is positively correlated with the cooling rate.

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