High and low temperature environment test method and system based on piezoelectric valve

Abstract

This invention discloses a high and low temperature environment testing method and system based on piezoelectric valves. This invention relates to the field of piezoelectric valve technology and solves the problem of difficulty in capturing hidden defects such as performance degradation of piezoelectric stacks and valve core jamming caused by thermal expansion and contraction. This invention introduces an input-output waveform alignment and comparison mechanism after the inflection point exceeds the limit, determines the standard process through overlapping matching of the climbing / falling segments, and quantitatively calculates the low-temperature signal attenuation and the proportion of high-temperature noise, distinguishing the fault type and severity, resulting in more objective and reproducible judgment results. Separate attenuation and noise exceedance judgments are established for high and low temperature environments to achieve fault location: low temperature focuses on signal loss caused by increased contact resistance and icing, while high temperature focuses on waveform interference caused by loose contact and oxidation leakage, making the test more targeted.

Description

Technical Field

[0001] This invention relates to the field of piezoelectric valve technology, specifically to a high and low temperature environment testing method and system based on piezoelectric valves. Background Technology

[0002] As a precision fluid control element integrating mechanics, electronics, and materials science, the piezoelectric valve achieves microsecond-level telescopic actuation by leveraging the inverse piezoelectric effect of piezoelectric stacking. It boasts advantages such as fast response speed, high control precision, and compact structure, and has been widely used in high-end industrial fields such as aerospace, energy and chemical industry, marine power, and semiconductor manufacturing. Especially in scenarios such as aero-engine fuel systems, spacecraft propulsion systems, and eVTOL thermal management systems, it is necessary to work stably for a long time in extreme high and low temperature environments. Its operational reliability is directly related to the safe operation and control precision of the entire equipment system.

[0003] As the core power component of a piezoelectric valve, the performance of the piezoelectric stack directly determines the valve's adjustment accuracy and service life. However, this component is extremely sensitive to temperature changes and is a typical "temperature-sensitive" element. In low-temperature environments, the arrangement of electric dipoles inside the piezoelectric stack is disturbed, reducing the piezoelectric coefficient. At the same time, the valve core electrical interface is prone to gaps due to thermal contraction and water vapor condensation, leading to increased contact resistance. In high-temperature environments, the piezoelectric stack is prone to piezoelectric coefficient drift, internal wafer detachment, and even depolarization. Furthermore, the valve core electrical interface may loosen due to thermal expansion and form an oxide layer due to electrode oxidation, causing poor contact. These problems can all lead to abnormal linearity of the piezoelectric valve excitation, signal transmission distortion, and subsequent valve core jamming, reduced adjustment accuracy, and in severe cases, paralyze the entire fluid control system, causing safety hazards or significant economic losses.

[0004] Currently, the testing methods for piezoelectric valves in high and low temperature environments in the industry are relatively crude, and generally suffer from the following technical pain points: First, there is a lack of a unified linearity judgment benchmark. Most tests rely on manual comparison of excitation-displacement data between high and low temperature environments and room temperature environments. The fluctuation range has not been quantified, which easily leads to human judgment errors and poor consistency of initial screening results. Second, the identification of abnormal inflection points of piezoelectric stack excitation linearity is not accurate enough. The reasonable number of inflection points and judgment criteria for low and high temperature environments are not distinguished, making it difficult to capture hidden defects such as performance degradation of piezoelectric stacks and valve core jamming caused by thermal expansion and contraction, which easily leads to missed judgments and misjudgments.

[0005] Furthermore, with the increasing demand for miniaturization, high precision, and high reliability in aerospace, defense, and other fields, the working environment of piezoelectric valves is becoming increasingly harsh. This places higher demands on their performance stability and signal transmission reliability under high and low temperature conditions. Existing testing methods can no longer meet the testing needs in practical applications. There is an urgent need for a testing method that can accurately, quantitatively, and efficiently complete the high and low temperature environment testing of piezoelectric valves, achieve accurate anomaly identification, and rapid fault location, so as to provide reliable support for the quality control and performance optimization of piezoelectric valves. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a high and low temperature environment testing method and system based on piezoelectric valves, which solves the problem of difficulty in capturing hidden defects such as performance degradation of piezoelectric stacks and valve core jamming caused by thermal expansion and contraction.

[0007] To achieve the above objectives, the present invention provides a high and low temperature environment testing method based on a piezoelectric valve, comprising the following steps: Step 1: Determine the piezoelectric stack excitation linearity associated with the piezoelectric valve in a normal room temperature environment as the standard linearity. Then, determine the piezoelectric stack excitation linearity generated by the piezoelectric valve in different high and low temperature environments. Compare the different piezoelectric stack excitation linearities with the standard linearity to identify whether the initial test meets the standard. The specific method is as follows: The piezoelectric valve is placed in a normal room temperature environment, and an excitation voltage is applied to the piezoelectric valve. The valve core offset parameters of the piezoelectric valve under the working state are collected by a laser displacement sensor for each set of excitation voltages. Multiple sets of valve core offset parameters are collected for each set of excitation voltages, and the average value of multiple sets of valve core offset parameters is processed to confirm the valve core offset value associated with the corresponding excitation voltage. A two-dimensional coordinate system is constructed with the excitation voltage as the horizontal coordinate axis and the valve core offset value as the vertical coordinate axis. Based on the different valve core offset values ​​associated with different excitation voltages, the relevant points are identified in the two-dimensional coordinate system and connected sequentially to obtain the piezoelectric stack excitation linearity of the piezoelectric valve in a normal room temperature environment, which is recorded as the standard linearity. Based on a preset linear deviation, a fluctuation range is constructed within the standard linearity. The linear trend associated with adjacent coordinate points within the standard linearity is confirmed. Based on the preset linear deviation and the linear trend associated with adjacent coordinate points, the fluctuation trend within the allowable range is locked: the proposed linear trend is Q. k The linear deviation is defined as C, where k represents different linear trends, and Q is used. k ×(1±C)=P kConfirm the two sets of fluctuation trends, and based on the two sets of fluctuation trends and the previous set of coordinate points, lock the position of the fluctuation point of the next set of coordinate points. Then confirm the position of the subsequent fluctuation points in turn, and connect the fluctuation points above the standard linearity in turn to confirm the upper fluctuation line. Then connect the fluctuation points below the standard linearity in turn to confirm the lower fluctuation line. The starting points of the upper fluctuation line and the lower fluctuation line are all the starting points of the standard linearity. Then, the piezoelectric valve was tested in low-temperature and high-temperature environments respectively. The piezoelectric stack excitation linearity associated with the low-temperature environment was locked and recorded as low-temperature linearity. Simultaneously, the piezoelectric stack excitation linearity associated with the high-temperature environment was locked and recorded as high-temperature linearity. Identify whether the confirmed low-temperature linearity and high-temperature linearity are both located between the upper and lower fluctuation lines. If so, proceed with the subsequent confirmation process. If not, directly generate a test failure signal for display. Step 2: Based on the piezoelectric valve's excitation linearity confirmed in low-temperature or high-temperature environments, and based on the linear trend of the preceding and following points, identify whether the number of abnormal inflection points within the piezoelectric stack's excitation linearity exceeds the limit. The specific method is as follows: The low-temperature linearity associated with the low-temperature environment or the high-temperature linearity associated with the high-temperature environment is denoted as the linearity to be processed. Based on the different two-dimensional coordinates associated with different coordinate points within the linearity to be processed, the linear trend associated with adjacent coordinate points is confirmed, and it is identified whether the linear trends ordered before and after are abnormal trends. The first set of linear trends is denoted as QS1, and the second set of linear trends is denoted as QS2. It is then evaluated whether the two sets of linear trends satisfy |QS2-QS1|÷QS1≥2. If they satisfy the condition, the coordinate points with the same linear trends in the two sets are denoted as abnormal inflection points. If they do not satisfy the condition, no marking is made. The number of abnormal inflection points GS1 within the low-temperature linearity is identified. If GS1≥1, a low-temperature oscilloscope retest signal is generated and the subsequent test process is executed. If GS1=0, it means that the piezoelectric valve has passed the test in the low-temperature environment, and a low-temperature test pass signal is output for display. The number of abnormal inflection points GS2 within the high-temperature linearity is identified. If GS2≥3, a high-temperature oscilloscope retest signal is generated and the subsequent test process is executed. If GS2<3, it means that the piezoelectric valve has passed the test in the high-temperature environment, and a high-temperature test pass signal is output for display. Step 3: When the number of abnormal inflection points within the piezoelectric stack excitation linearity exceeds the standard, a signal generator sends an oscilloscope signal to the input end of the valve core. The oscilloscope signals from both the input and output ends of the valve core are collected and compared to identify the standard process. Then, the attenuation level or noise ratio of the corresponding oscilloscope signal within the standard process is identified to determine if it exceeds the standard. Based on the identification results, a related signal is output for display. The specific method is as follows: Record the waveform of the oscilloscope signal at the input end as the input waveform and the waveform of the oscilloscope signal at the output end as the output waveform. Place the input waveform and the output waveform in the same value graph and move the input waveform or the output waveform horizontally. Record the percentage of overlap in duration during the movement process. The time period of the waveform's rising segment within the input or output waveform is denoted as the rising segment, and the time period of the waveform's falling segment is denoted as the falling segment. During the movement process, the overlapping time periods of the input or output waveform that belong to the same rising segment are identified and denoted as the overlapping rising segment. Simultaneously, the overlapping time periods that belong to the same falling segment are identified and denoted as the overlapping falling segment. The total overlap duration of the overlapping rising and falling segments is identified and denoted as ZX. The total duration of the input waveform is denoted as ZS. Using the formula ZX÷ZS=ZB, the overlap ratio ZB associated with the corresponding movement process is identified. Based on the different ZB values ​​associated with different movement processes, the maximum value is selected, and the movement process associated with the maximum value is denoted as the standard process. The method for identifying the results of low-temperature oscilloscope retest signals is as follows: Based on the generated low-temperature oscilloscope retest signal, the piezoelectric valve is placed in a low-temperature environment, and the attenuation of the corresponding oscilloscope signal of the piezoelectric valve is tested and evaluated: According to the established standard procedure, the signal amplitude belonging to the input waveform at the same moment is denoted as SF. o The signal amplitude belonging to the output waveform is denoted as CF. o Where 'o' represents different times, using: SJ o = (SF o -CF o Confirm the attenuation amplitude SJ associated with the corresponding time. o Then, the confirmed attenuation amplitudes SJ o Perform averaging to confirm the average attenuation value JZ, and lock the maximum amplitude Fmax of the input waveform from it. If JZ satisfies: (JZ÷Fmax)≥15%, then directly output the low temperature test failure signal for display. If JZ does not satisfy, then directly output the low temperature test success signal for display. The method for identifying the results of high-temperature oscilloscope retest signals is as follows: Based on the generated high-temperature oscilloscope retest signal, the piezoelectric valve is placed in a high-temperature environment, and the noise ratio of the corresponding oscilloscope signal of the piezoelectric valve is measured and evaluated: According to the established standard process, the waveform segments in the output waveform that do not belong to the overlapping rise or fall period are recorded as clutter segments, and the bus length L1 of the clutter segment is recorded. The bus length of the output waveform is recorded as L2. If L1÷L2≥30%, the high temperature test failure signal is directly output for display. If it does not meet the requirement, the high temperature test success signal is directly output for display.

[0008] Preferably, the high and low temperature environment testing system based on a piezoelectric valve includes: For the initial test to determine compliance, the piezoelectric stack excitation linearity associated with the piezoelectric valve in a normal room temperature environment is determined as the standard linearity. Then, the piezoelectric stack excitation linearity generated by the piezoelectric valve in different high and low temperature environments is determined. The different piezoelectric stack excitation linearities are compared with the standard linearity to identify whether the initial test meets the standard. The abnormal inflection point identification end identifies whether the number of abnormal inflection points within the piezoelectric stack excitation linearity is excessive based on the linear trend of the piezoelectric valve in low temperature or high temperature environment and the linear trend of the previous and next points. If the number of abnormal inflection points is excessive, the signal waveform transmission test process is executed. If the number of abnormal inflection points is not excessive, the test pass signal is generated directly. At the output end of the identification results, when the number of abnormal inflection points within the linearity of the piezoelectric stack exceeds the standard, a signal generator sends an oscilloscope signal to the input end of the valve core. Based on the oscilloscope, the oscilloscope signals at the input and output ends of the valve core are collected and compared to identify whether the attenuation degree or noise ratio of the corresponding oscilloscope signal exceeds the standard. Based on the identification results, the associated signal is output for display.

[0009] This invention provides a high and low temperature environment testing method and system based on a piezoelectric valve. Compared with the prior art, it has the following advantages: Using the room temperature standard linearity ±5% fluctuation range as a unified judgment benchmark, we can achieve quantitative comparison of excitation linearity under high and low temperature environments, avoid human judgment errors, and improve the efficiency and consistency of initial screening.

[0010] By automatically identifying abnormal inflection points through the threshold of abrupt changes in the linear trend of adjacent segments, and setting differentiated judgment rules for low-temperature inflection points and high-temperature multiple inflection points, the system can accurately capture hidden defects such as valve core jamming and piezoelectric stack performance degradation caused by thermal expansion and contraction, thereby achieving early fault warning.

[0011] After the inflection point exceeds the standard, an input-output waveform alignment and comparison mechanism is introduced. The standard process is determined by the overlapping matching of the climbing / falling segments. The attenuation of low temperature signals and the proportion of high temperature noise are quantitatively calculated to distinguish the fault type and severity. The judgment results are more objective and reproducible.

[0012] For high and low temperature environments, separate attenuation and noise exceedance criteria are established to enable fault location: low temperature focuses on signal loss caused by increased contact resistance and icing, while high temperature focuses on waveform interference caused by loose contacts and oxidation leakage, making the testing more targeted.

[0013] The entire method forms a graded and progressive testing process, from initial screening of linearity to identification of inflection point anomalies to in-depth verification of waveforms. It can quickly screen out obviously unqualified products and deeply verify suspicious samples, taking into account both testing efficiency and reliability, and comprehensively improving the quality control capability of piezoelectric valves in extreme high and low temperature environments. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the method flow of the present invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] First Embodiment Please see Figure 1 This application provides a high and low temperature environment testing method based on a piezoelectric valve, including the following steps: Step 1: Determine the piezoelectric stack excitation linearity associated with the piezoelectric valve in a normal room temperature environment as the standard linearity. Then, determine the piezoelectric stack excitation linearity generated by the piezoelectric valve in different high and low temperature environments. Compare the different piezoelectric stack excitation linearities with the standard linearity to identify whether the initial test meets the standard. Specifically, the test environment includes: Standard linearity test environment (room temperature reference environment): temperature 25±5℃, humidity ≤60%, no electromagnetic interference, no external force interference, piezoelectric valve in no-load state, consistent with the "initial performance reference test" environment in the early stage of test preparation, to ensure the accuracy and comparability of standard linearity.

[0017] Low temperature test environment: Controlled according to the set parameters, including normal low temperature environment (-40℃) and extreme low temperature environment (-55℃, optional). The temperature change rate must be maintained at 5℃ / min. After reaching the set temperature, it must be kept at the temperature for 60 minutes to ensure that all components of the sample reach thermal equilibrium and there is no condensation interference (dry nitrogen gas is introduced). The piezoelectric valve is in the no-load state (powered-on load condition is optional).

[0018] High temperature test environment: Controlled according to the set parameters, including normal high temperature environment (125℃) and extreme high temperature environment (150℃, optional). The temperature change rate must be maintained at 5℃ / min. After reaching the set temperature, it must be kept at the temperature for 60 minutes to ensure that all components of the sample reach thermal equilibrium. The piezoelectric valve is in no-load state (optional energized load condition).

[0019] The specific method for identifying whether the initial test of the piezoelectric valve meets the standards is as follows: The piezoelectric valve is placed in a normal room temperature environment, and excitation voltages (0V, 25V, 50V, 75V, 100V) are applied to the piezoelectric valve. The valve core offset parameters under each excitation voltage are collected by a laser displacement sensor. Multiple sets of valve core offset parameters are collected for each excitation voltage, with no less than three sets. The average value of the multiple sets of valve core offset parameters is processed to confirm the valve core offset value associated with the corresponding excitation voltage. Then, a two-dimensional coordinate system is constructed with the excitation voltage as the horizontal coordinate axis and the valve core offset value as the vertical coordinate axis. Based on the different valve core offset values ​​associated with different excitation voltages, the relevant points are identified in the two-dimensional coordinate system and connected sequentially to obtain the piezoelectric stack excitation linearity of the piezoelectric valve in a normal room temperature environment, which is recorded as the standard linearity. Based on a preset linear deviation (±5%), a fluctuation range is constructed within the standard linearity. The linear trend associated with adjacent coordinate points within the standard linearity is confirmed. The coordinates associated with the next coordinate point are determined to be (X1, Y1), and the coordinates associated with the previous coordinate point are determined to be (X2, Y2). The linear trend is calculated as: Linear trend = (Y1-Y2) ÷ (X1-X2). Based on the preset linear deviation and the linear trend associated with adjacent coordinate points, the fluctuation trend within the allowable range is locked: the proposed linear trend is Q. k The linear deviation is defined as C, where k represents different linear trends, and Q is used. k ×(1±C)=P k Confirm the two sets of fluctuation trends, and based on the two sets of fluctuation trends and the previous set of coordinate points, lock the position of the fluctuation point of the next set of coordinate points. Then, based on the previous set of coordinate points, confirm the position of the subsequent fluctuation points. Then, connect the fluctuation points above the standard linearity to confirm the upper fluctuation line. Then, connect the fluctuation points below the standard linearity to confirm the lower fluctuation line. The starting points of the upper and lower fluctuation lines are all the starting points of the standard linearity. Then, the piezoelectric valve was tested in a low-temperature environment (-40℃) or a high-temperature environment (125℃). The piezoelectric stack excitation linearity associated with the low-temperature environment was locked and recorded as the low-temperature linearity. At the same time, the piezoelectric stack excitation linearity associated with the high-temperature environment was locked and recorded as the high-temperature linearity (the confirmation method is the same as the method for confirming the standard linearity in the standard room temperature environment). If the confirmed low-temperature linearity and high-temperature linearity are both located between the upper and lower fluctuation lines, the preliminary test is considered qualified and the subsequent confirmation process is executed. If not, the preliminary test is considered unqualified, and the piezoelectric valve core is severely affected by low and high temperatures, and an inspection failure signal is directly generated and displayed. Specifically, regardless of whether the piezoelectric valve is in a low-temperature or high-temperature environment, due to the thermal expansion and contraction of the piezoelectric valve, a corresponding linear deviation is allowed during the testing process. The degree of deviation must not exceed 5%. Therefore, in the actual testing process, the low-temperature test corresponds to the piezoelectric stack excitation linearity, and the high-temperature test corresponds to a set of piezoelectric stack excitation linearities. Based on the standard linearity determined in the standard testing environment and the confirmed fluctuation range, it is possible to effectively confirm whether the corresponding piezoelectric stack excitation linearities confirmed at low and high temperatures are within the corresponding fluctuation range, thereby comprehensively evaluating whether the piezoelectric valve meets the standards in the initial testing process.

[0020] Step 2: Based on the piezoelectric stack excitation linearity confirmed by the piezoelectric valve in low temperature or high temperature environment, and based on the linear trend of the points before and after, identify whether the number of abnormal inflection points in the piezoelectric stack excitation linearity exceeds the standard. If it exceeds the standard, execute the signal waveform transmission test process. If it does not exceed the standard, directly generate a test qualified signal. The specific identification and processing method is as follows: The low-temperature linearity associated with a low-temperature environment or the high-temperature linearity associated with a high-temperature environment is denoted as the linearity to be processed. Based on the different two-dimensional coordinates associated with different coordinate points within the linearity to be processed, the linear trend associated with adjacent coordinate points is confirmed. The coordinates associated with the next coordinate point are defined as (X1, Y1), and the coordinates associated with the previous coordinate point are defined as (X2, Y2). The linear trend is calculated as: linear trend = (Y1-Y2) ÷ (X1-X2). The linear trends are then identified as abnormal trends. The first set of linear trends is denoted as QS1, and the second set of linear trends is denoted as QS2. The two sets of linear trends are evaluated to see if they satisfy |QS2-QS1| ÷ QS1 ≥ 2. If they satisfy this condition, the coordinate points with the same linear trends in the two sets are marked as abnormal inflection points. If they do not satisfy this condition, no marking is made. The number of abnormal inflection points GS1 within the low-temperature linearity is identified. If GS1≥1, it means that there is an abnormal inflection point. Under normal circumstances, there will be no abnormal inflection points in the low-temperature environment. Its trend is basically the same as the overall trend of the standard linearity and there will be no drastic fluctuations. A low-temperature oscilloscope retest signal is generated and the subsequent test process is executed. If GS1=0, it means that the piezoelectric valve has passed the test in the low-temperature environment and a low-temperature test pass signal is output for display. The number of abnormal inflection points GS2 within the high-temperature linearity is identified. If GS2 ≥ 3, it means that there are too many abnormal inflection points. Under normal circumstances, only when the valve core is damaged or broken will the parameters between the excitation voltage and the valve core deviate significantly, resulting in too many abnormal inflection points. For this situation, oscilloscope testing is required to evaluate the working state of the piezoelectric valve in the corresponding environment, generate a high-temperature oscilloscope retest signal, and execute the subsequent test process. If GS2 < 3, it means that the piezoelectric valve has passed the test in the high-temperature environment, and a high-temperature test pass signal is output for display. Step 3: When the number of abnormal inflection points within the linearity of the piezoelectric stack exceeds the standard, a signal generator is used to send an oscilloscope signal to the input end of the valve core. Based on the oscilloscope, the oscilloscope signals at the input and output ends of the valve core are collected and compared to identify whether the attenuation degree or noise ratio of the corresponding oscilloscope signal exceeds the standard. Based on the identification results, the associated signal is output for display. The specific recognition test processing method is as follows: Record the waveform of the oscilloscope signal at the input end as the input waveform and the waveform of the oscilloscope signal at the output end as the output waveform. Place the input waveform and the output waveform in the same value graph and move the input waveform or the output waveform horizontally. Record the percentage of overlap in duration during the movement process. The time period of the waveform's rising segment within the input or output waveform is denoted as the rising segment, and the time period of the waveform's falling segment is denoted as the falling segment. During the movement process, the overlapping time periods of the input or output waveform that belong to the same rising segment are identified and denoted as the overlapping rising segment. Simultaneously, the overlapping time periods that belong to the same falling segment are identified and denoted as the overlapping falling segment. The total overlap duration of the overlapping rising and falling segments is identified and denoted as ZX. The total duration of the input waveform is denoted as ZS. Using the formula ZX÷ZS=ZB, the overlap ratio ZB associated with the corresponding movement process is identified. Based on the different ZB values ​​associated with different movement processes, the maximum value is selected, and the movement process associated with the maximum value is denoted as the standard process. Based on the generated low-temperature oscilloscope retest signal, the piezoelectric valve is placed in a low-temperature environment, and the attenuation of the corresponding oscilloscope signal of the piezoelectric valve is tested and evaluated: According to the established standard procedure, the signal amplitude belonging to the input waveform at the same moment is denoted as SF. o The signal amplitude belonging to the output waveform is denoted as CF. o Where 'o' represents different times, using: SJ o = (SF o -CF o Confirm the attenuation amplitude SJ associated with the corresponding time. o Then, the confirmed attenuation amplitudes SJ oPerform averaging to confirm the attenuation value JZ, and lock the maximum amplitude Fmax of the input waveform from it. If JZ satisfies (JZ÷Fmax)≥15%, it means that the attenuation is too severe, and the corresponding piezoelectric valve fails the test in the low temperature environment. In this case, the low temperature test failure signal will be directly output for display. If JZ does not meet the requirement, the low temperature test pass signal will be directly output for display. Based on the generated high-temperature oscilloscope retest signal, the piezoelectric valve is placed in a high-temperature environment, and the noise ratio of the corresponding oscilloscope signal of the piezoelectric valve is measured and evaluated: According to the established standard process, the waveform segments in the output waveform that do not belong to the overlapping rise or fall period are recorded as noise segments, and the bus length L1 of the noise segment is recorded. The bus length of the output waveform is recorded as L2. If L1÷L2≥30%, it means that the noise is too serious, and it means that the corresponding piezoelectric valve fails the test in the high temperature environment. In this case, the high temperature test failure signal is directly output for display. If it does not meet the requirements, the high temperature test pass signal is directly output for display. In low-temperature environments, signals are attenuated, while in high-temperature environments, excessive noise exists within the signal. Under high-temperature conditions, the valve core electrical interface and piezoelectric stacked electrodes may loosen due to thermal expansion. At the same time, high temperatures accelerate the oxidation of the electrode surface, forming an oxide layer, which leads to unstable contact resistance, fluctuating between large and small values, causing output signal fluctuations and generating noise. In addition, high temperatures cause the insulation layer of the wires to soften and age, which may also cause slight leakage between wires, generating noise interference. Meanwhile, low temperatures may cause residual moisture at the interface to condense into ice, further increasing the contact resistance. According to Ohm's law, increased resistance will lead to increased energy loss during signal transmission, thus causing signal amplitude attenuation. This is the main reason for signal attenuation at low temperatures.

[0021] Second Embodiment A high and low temperature environment testing system based on piezoelectric valves includes: For the initial test to determine compliance, the piezoelectric stack excitation linearity associated with the piezoelectric valve in a normal room temperature environment is determined as the standard linearity. Then, the piezoelectric stack excitation linearity generated by the piezoelectric valve in different high and low temperature environments is determined. The different piezoelectric stack excitation linearities are compared with the standard linearity to identify whether the initial test meets the standard. The abnormal inflection point identification end identifies whether the number of abnormal inflection points within the piezoelectric stack excitation linearity is excessive based on the linear trend of the piezoelectric valve in low temperature or high temperature environment and the linear trend of the previous and next points. If the number of abnormal inflection points is excessive, the signal waveform transmission test process is executed. If the number of abnormal inflection points is not excessive, the test pass signal is generated directly. At the output end of the identification results, when the number of abnormal inflection points within the linearity of the piezoelectric stack exceeds the standard, a signal generator sends an oscilloscope signal to the input end of the valve core. Based on the oscilloscope, the oscilloscope signals at the input and output ends of the valve core are collected and compared to identify whether the attenuation degree or noise ratio of the corresponding oscilloscope signal exceeds the standard. Based on the identification results, the associated signal is output for display.

[0022] It also includes testing equipment, specifically: a high and low temperature alternating test chamber (temperature control accuracy ±0.5℃, temperature change rate adjustable from 1 to 10℃ / min, volume sufficient for sample + fixture placement, and temperature profile programming function), a laser displacement sensor (accuracy ±0.1μm, used to monitor valve core displacement changes), a sealing test device (gas / liquid medium, pressure adjustable), an insulation resistance tester, a high-definition camera (used to observe appearance changes), an electrical performance tester (used to monitor valve core drive signal, contact resistance, and piezoelectric stack excitation response), a data acquisition instrument (synchronously acquires valve core electrical parameters and displacement and temperature data), a signal generator (used to output standard drive signals and assist in verifying transmission stability), and an oscilloscope (used to capture drive signal waves). (For shape analysis and signal integrity), during the test, the marked piezoelectric valve is installed in a special fixture, ensuring it is firmly fixed and without looseness; connect the laser displacement sensor (aligned with the valve core to monitor displacement changes), the temperature probe (closely attached to key parts), and the sealing test device (if simultaneous sealing testing is required); place the fixture in a high and low temperature test chamber, connect the electrical circuitry (not only for subsequent performance testing, but also for connecting the electrical performance tester, oscilloscope, and signal generator for real-time monitoring and comparison of the valve core's electrical performance during the cycle), close the test chamber door, and debug the equipment to ensure that the data acquisition of temperature, displacement, sealing detection, and valve core electrical parameters is normal; calibrate the electrical performance tester and oscilloscope in advance with standard calibration parts to ensure the accuracy of the calibration data.

[0023] Some of the data in the above formulas are numerical calculations with dimensions removed, and the contents not described in detail in this specification are all prior art known to those skilled in the art.

[0024] The above embodiments are only used to illustrate the technical methods of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical methods of the present invention without departing from the spirit and scope of the technical methods of the present invention.

Claims

1. A high and low temperature environment testing method based on a piezoelectric valve, characterized in that, Includes the following steps: Step 1: Determine the piezoelectric stack excitation linearity associated with the piezoelectric valve in a normal room temperature environment as the standard linearity. Then, determine the piezoelectric stack excitation linearity generated by the piezoelectric valve in different high and low temperature environments. Compare the different piezoelectric stack excitation linearities with the standard linearity to identify whether the initial test meets the standard. Step 2: Based on the piezoelectric valve's excitation linearity in low-temperature or high-temperature environments, and based on the linear trend of the preceding and following points, identify whether the number of abnormal inflection points within the piezoelectric stack excitation linearity exceeds the standard. Step 3: When the number of abnormal inflection points within the linearity of the piezoelectric stack exceeds the standard, a signal generator is used to send an oscilloscope signal to the input end of the valve core. Based on the oscilloscope, the oscilloscope signals at the input and output ends of the valve core are collected and compared to lock the standard process. Then, the attenuation degree or noise ratio of the corresponding oscilloscope signal in the standard process is identified as exceeding the standard, and the associated signal is output and displayed based on the identification results.

2. The high and low temperature environment testing method based on a piezoelectric valve according to claim 1, characterized in that, In step one, the specific method for identifying whether the initial test of the piezoelectric valve meets the standard is as follows: A two-dimensional coordinate system is constructed with the excitation voltage as the horizontal coordinate axis and the valve core offset value as the vertical coordinate axis. Based on the different valve core offset values ​​associated with different excitation voltages, the relevant points are identified in the two-dimensional coordinate system and connected sequentially to obtain the piezoelectric stack excitation linearity of the piezoelectric valve in a normal room temperature environment, which is recorded as the standard linearity. Based on a preset linear deviation, a fluctuation range is constructed within the standard linearity. The linear trend associated with adjacent coordinate points within the standard linearity is confirmed. Based on the preset linear deviation and the linear trend associated with adjacent coordinate points, the fluctuation trend within the allowable range is locked: the proposed linear trend is Q. k The linear deviation is defined as C, where k represents different linear trends, and Q is used. k ×(1±C)=P k Confirm the two sets of fluctuation trends, and based on the two sets of fluctuation trends and the previous set of coordinate points, lock the position of the fluctuation point of the next set of coordinate points. Then confirm the position of the subsequent fluctuation points in turn, and connect the fluctuation points above the standard linearity in turn to confirm the upper fluctuation line. Then connect the fluctuation points below the standard linearity in turn to confirm the lower fluctuation line. The starting points of the upper fluctuation line and the lower fluctuation line are all the starting points of the standard linearity. Then, the piezoelectric valve was tested in low-temperature and high-temperature environments respectively. The piezoelectric stack excitation linearity associated with the low-temperature environment was locked and recorded as low-temperature linearity. Simultaneously, the piezoelectric stack excitation linearity associated with the high-temperature environment was locked and recorded as high-temperature linearity. Identify whether the confirmed low-temperature linearity and high-temperature linearity are both located between the upper and lower fluctuation lines. If so, proceed with the subsequent confirmation process. If not, directly generate a test failure signal for display.

3. The high and low temperature environment testing method based on a piezoelectric valve according to claim 2, characterized in that, The valve core offset value is determined as follows: The piezoelectric valve is placed in a normal room temperature environment, and an excitation voltage is applied to the piezoelectric valve. The valve core offset parameters of the piezoelectric valve under the working state are collected by a laser displacement sensor for each set of excitation voltages. Multiple sets of valve core offset parameters are collected for each set of excitation voltages, and the average value of multiple sets of valve core offset parameters is processed to confirm the valve core offset value associated with the corresponding excitation voltage.

4. The high and low temperature environment testing method based on a piezoelectric valve according to claim 1, characterized in that, In step two, the specific method for determining the abnormal inflection point is as follows: The low-temperature linearity associated with the low-temperature environment or the high-temperature linearity associated with the high-temperature environment is denoted as the linearity to be processed. Based on the different two-dimensional coordinates associated with different coordinate points within the linearity to be processed, the linear trend associated with adjacent coordinate points is confirmed, and it is identified whether the linear trends ordered before and after are abnormal trends. The first set of linear trends is denoted as QS1, and the second set of linear trends is denoted as QS2. It is then evaluated whether the two sets of linear trends satisfy |QS2-QS1|÷QS1≥2. If they satisfy the condition, the coordinate points with the same linear trends in the two sets are denoted as abnormal inflection points. If they do not satisfy the condition, no marking is made. The number of abnormal inflection points GS1 within the low-temperature linearity is identified. If GS1≥1, a low-temperature oscilloscope retest signal is generated and the subsequent test process is executed. If GS1=0, it means that the piezoelectric valve has passed the test in the low-temperature environment, and a low-temperature test pass signal is output for display.

5. The high and low temperature environment testing method based on a piezoelectric valve according to claim 4, characterized in that, In step two, the specific methods for determining the abnormal inflection point also include: The number of abnormal inflection points GS2 within the high-temperature linearity is identified. If GS2≥3, a high-temperature oscilloscope retest signal is generated and the subsequent test process is executed. If GS2<3, it means that the piezoelectric valve has passed the test in the high-temperature environment, and a high-temperature test pass signal is output for display.

6. The high and low temperature environment testing method based on a piezoelectric valve according to claim 1, characterized in that, In step three, the specific method for locking the standard process is as follows: Record the waveform of the oscilloscope signal at the input end as the input waveform and the waveform of the oscilloscope signal at the output end as the output waveform. Place the input waveform and the output waveform in the same value graph and move the input waveform or the output waveform horizontally. Record the percentage of overlap in duration during the movement process. The time intervals within the rising segment of the input or output waveform are denoted as the rising segment, and the time intervals within the falling segment are denoted as the falling segment. During the movement process, the overlapping segments of the input or output waveforms belonging to the rising segment are identified and denoted as the overlapping rising segment. Simultaneously, the overlapping segments belonging to the falling segment are identified and denoted as the overlapping falling segment. The total overlap duration of the overlapping rising and falling segments is identified and denoted as ZX. The total duration of the input waveform is denoted as ZS. The overlap ratio ZB associated with the corresponding movement process is identified using the formula: ZX ÷ ZS = ZB. Based on the different ZB values ​​associated with different movement processes, the maximum value is selected, and the movement process associated with the maximum value is denoted as the standard process.

7. The high and low temperature environment testing method based on a piezoelectric valve according to claim 6, characterized in that, In step three, the method for identifying the results of the low-temperature oscilloscope retest signal is as follows: Based on the generated low-temperature oscilloscope retest signal, the piezoelectric valve is placed in a low-temperature environment, and the attenuation of the corresponding oscilloscope signal of the piezoelectric valve is tested and evaluated: According to the established standard procedure, the signal amplitude belonging to the input waveform at the same moment is denoted as SF. o The signal amplitude belonging to the output waveform is denoted as CF. o Where 'o' represents different times, using: SJ o = (SF o -CF o Confirm the attenuation amplitude SJ associated with the corresponding time. o Then, the confirmed attenuation amplitudes SJ o Perform averaging to confirm the average attenuation value JZ, and lock the maximum amplitude Fmax of the input waveform from it. If JZ satisfies: (JZ÷Fmax)≥15%, then directly output the low temperature test failure signal for display. If JZ does not satisfy, then directly output the low temperature test success signal for display.

8. The high and low temperature environment testing method based on a piezoelectric valve according to claim 6, characterized in that, In step three, the method for identifying the results of the high-temperature oscilloscope retest signal is as follows: Based on the generated high-temperature oscilloscope retest signal, the piezoelectric valve is placed in a high-temperature environment, and the noise ratio of the corresponding oscilloscope signal of the piezoelectric valve is measured and evaluated: According to the established standard process, the waveform segments in the output waveform that do not belong to the overlapping rise or fall period are recorded as clutter segments, and the bus length L1 of the clutter segment is recorded. The bus length of the output waveform is recorded as L2. If L1÷L2≥30%, the high temperature test failure signal is directly output for display. If it does not meet the requirement, the high temperature test success signal is directly output for display.

9. A high and low temperature environment testing system based on a piezoelectric valve, wherein the system operates according to any one of claims 1-8, characterized in that, include: For the initial test to determine compliance, the piezoelectric stack excitation linearity associated with the piezoelectric valve in a normal room temperature environment is determined as the standard linearity. Then, the piezoelectric stack excitation linearity generated by the piezoelectric valve in different high and low temperature environments is determined. The different piezoelectric stack excitation linearities are compared with the standard linearity to identify whether the initial test meets the standard. The abnormal inflection point identification end identifies whether the number of abnormal inflection points within the piezoelectric stack excitation linearity is excessive based on the linear trend of the piezoelectric valve in low temperature or high temperature environment and the linear trend of the previous and next points. If the number of abnormal inflection points is excessive, the signal waveform transmission test process is executed. If the number of abnormal inflection points is not excessive, the test pass signal is generated directly. At the output end of the identification results, when the number of abnormal inflection points within the linearity of the piezoelectric stack exceeds the standard, a signal generator sends an oscilloscope signal to the input end of the valve core. Based on the oscilloscope, the oscilloscope signals at the input and output ends of the valve core are collected and compared to identify whether the attenuation degree or noise ratio of the corresponding oscilloscope signal exceeds the standard. Based on the identification results, the associated signal is output for display.

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