A method for fault analysis of a solenoid valve based on pulse control technology

Abstract

The application discloses a method for fault analysis of an electromagnetic valve based on pulse control technology, and comprises the following steps: S1, sending a pulse measurement signal to the electromagnetic valve and acquiring a pulse measurement voltage V P of the electromagnetic valve; P S2, judging the attraction state of the electromagnetic valve according to the pulse measurement voltage V P ; S3, if the electromagnetic valve is not attracted or the attraction is not in place, sending a direct current measurement signal to the electromagnetic valve, acquiring a direct current measurement voltage V D of the electromagnetic valve, and judging the fault type of the electromagnetic valve according to the direct current measurement voltage V D . The inductance of the electromagnetic valve coil is different when the valve core position of the electromagnetic valve is different, so that a pulse current can be passed through the electromagnetic valve coil, and the position of the valve core can be judged by measuring the voltage value of the electromagnetic valve. When the coil of the electromagnetic valve appears a short circuit or an open circuit fault, the voltage of the coil when passing the direct current deviates from the normal value, so that the reason for the electromagnetic valve not being attracted in place is judged by measuring the voltage value of the electromagnetic valve under the direct current measurement signal, whether the coil is a fault or a mechanical fault.

Description

Technical Field

[0001] The present invention relates to the technical field of wired solenoid valve fault diagnosis, and in particular to a method for performing fault analysis on a solenoid valve based on a pulse control technology. Background Art

[0002] Existing gas alarms are typically connected to a solenoid valve in the gas pipeline. When the gas alarm detects a gas leak, it controls the solenoid valve to close the gas pipeline, preventing further leakage. However, since these solenoid valves are typically wired, the solenoid valve's wiring can often become open or short-circuited due to insect bites, weathering, and corrosion, preventing the gas alarm from properly closing the valve. Furthermore, the solenoid valve itself can become inoperable or fail to close properly due to aging and corrosion over time, making it difficult to control the valve in the event of a gas leak.

[0003] Currently, fault diagnosis and status detection technologies for solenoid valves mostly determine whether the solenoid valve is connected properly by detecting the level of the solenoid valve circuit. This method can only determine whether the solenoid valve is working properly, but cannot accurately determine the type of solenoid valve fault. This requires maintenance personnel to manually troubleshoot the fault type, reducing solenoid valve maintenance efficiency.

[0004] More complex technologies utilize artificial intelligence and other methods to automatically analyze the solenoid valve's current signal, thereby determining its operating status and fault type. However, this requires the gas alarm to have strong data processing capabilities, or to transmit the gas alarm data to a control center for centralized analysis, which undoubtedly increases the cost of using the gas alarm. Summary of the Invention

[0005] In order to solve the technical problem of high cost of fault analysis and detection of wired solenoid valves in the prior art, the present application provides a method for fault analysis of solenoid valves based on pulse control technology, comprising the following steps:

[0006] S1. Send a pulse measurement signal to the solenoid valve and obtain the pulse measurement voltage V of the solenoid valve P ;

[0007] S2, measuring the voltage V according to the pulse P Determining the closed state of the solenoid valve;

[0008] S3: If the solenoid valve is not closed or is not closed properly, a DC measurement signal is sent to the solenoid valve to obtain the DC measurement voltage V of the solenoid valve. D , according to the DC measurement voltage V D Determine the fault type of the solenoid valve.

[0009] The solenoid valve coil's inductance varies depending on the position of the valve core. Therefore, a pulsed current can be passed through the solenoid valve coil, and the valve core position can be determined by measuring the solenoid valve's voltage. Furthermore, when the solenoid valve coil experiences a short circuit or open circuit, the coil's voltage deviates from its normal value when DC current is applied. Therefore, by measuring the solenoid valve's voltage under a DC measurement signal, it can be determined whether the solenoid valve's failure to close is due to a coil fault or a mechanical failure. This eliminates the need for complex data processing, effectively reducing the computing power required of the processing chip and lowering operating costs.

[0010] Specifically, the closing state of the solenoid valve is determined by the following steps:

[0011] S21, when the system is initialized, the solenoid valve is set to the non-attractive state, the pulse measurement signal is sent to the solenoid valve, and the non-attractive state voltage V is obtained. a , set the solenoid valve to the energized state, send the pulse measurement signal to the solenoid valve, and obtain the energized state voltage V b ;

[0012] S22, calculate the status judgment voltage V1:

[0013] S23, if And V a >V b ,or And V a <V b , the solenoid valve is in the non-attractive state. And V a <V b ,or And V a >V b , the solenoid valve is in the attracted state.

[0014] Specifically, the pulse measurement voltage V P Obtain it by following these steps:

[0015] S11, continuously send a pulse measurement signal to the solenoid valve, and after a first period of time, perform voltage sampling on the solenoid valve to obtain multiple pulse voltage sampling values, and calculate the average value of all the pulse voltage sampling values, which is the pulse measurement voltage V P .

[0016] Specifically, the closing state of the solenoid valve is determined by the following steps:

[0017] S24. When the system is initialized, the solenoid valve is set to an unengaged state, the pulse measurement signal is sent to the solenoid valve, and a voltage interval of the unengaged state is obtained; the solenoid valve is set to an engaged state, the pulse measurement signal is sent to the solenoid valve, and a voltage interval of the engaged state is obtained;

[0018] S25, constructing a voltage interval for insufficient engagement according to the voltage interval in the unengaged state and the voltage interval in the engaged state;

[0019] S26, measuring the voltage V according to the pulse P The position of the solenoid valve is used to determine the closed state of the solenoid valve.

[0020] When the solenoid valve core fails to close due to coil or mechanical reasons, the pulse measurement voltage V P It will be between the un-attracted state voltage V a And the pull-in state voltage V b Therefore, simply dividing the solenoid valve's energizing state into energized or non-energized may lead to misjudgment. P Determining the solenoid valve's energized state by determining the voltage range in which it is located can effectively avoid misjudgment and improve the accuracy of solenoid valve fault classification.

[0021] Specifically, the voltage interval in the non-engaged state is obtained by the following steps:

[0022] S241. Continuously send the pulse measurement signal to the solenoid valve, and after a first period of time, perform voltage sampling on the solenoid valve to obtain a plurality of pulse voltage sampling values, filter out the maximum and minimum values ​​from all the pulse voltage sampling values, and construct the non-engaged state voltage interval.

[0023] Specifically, the voltage interval of the non-attractive state is constructed by the following steps:

[0024] S251. Determine whether the maximum value of the engaged state voltage interval is greater than the maximum value of the unengaged state voltage interval. If so, construct the unengaged voltage interval based on the minimum value of the engaged state voltage interval and the maximum value of the unengaged state voltage interval. If not, construct the unengaged voltage interval based on the maximum value of the engaged state voltage interval and the minimum value of the unengaged state voltage interval.

[0025] Specifically, the fault type of the solenoid valve is determined by the following steps:

[0026] S31, obtain the open circuit state voltage V k , short circuit voltage V d And the normal state voltage V z ;

[0027] S32, calculate the state judgment voltage V1: V1=|V D -V z |;

[0028] S33, if V D <V k , then the solenoid valve is open circuit, if V D >V d , the solenoid valve has a short circuit; if the state judgment voltage V1 is less than or equal to a first threshold, the solenoid valve has a mechanical failure; if the state judgment voltage V1 is greater than the first threshold, the solenoid valve has a coil failure.

[0029] Specifically, the open circuit voltage V k , short circuit voltage V d And the normal state voltage V z Obtain it by following these steps:

[0030] S311: When the system is initialized, the solenoid valve is set to an open circuit state, the DC measurement signal is sent to the solenoid valve, and the open circuit state voltage V is obtained. k , set the solenoid valve to a short-circuit state, send the DC measurement signal to the solenoid valve, and obtain the short-circuit state voltage V d , set the solenoid valve to a normal state, send the DC measurement signal to the solenoid valve, and obtain the normal state voltage V z .

[0031] Furthermore, the short-circuit voltage V d The process also includes:

[0032] S312, changing the short-circuit position of the solenoid valve multiple times, sending the DC measurement signal to the solenoid valve, and obtaining multiple short-circuit measurement voltages;

[0033] S313, filter out the minimum value from all the short-circuit measurement voltages, which is the short-circuit state voltage V d .

[0034] Specifically, the normal state voltage V z And the first threshold is obtained by the following steps:

[0035] S314: When the system is initialized, the solenoid valve is set to a non-engaged state, the DC measurement signal is continuously sent to the solenoid valve, and after a first period of time, the voltage of the solenoid valve is sampled to obtain a plurality of DC voltage sampling values;

[0036] S315, setting the solenoid valve to an engaged state, continuously sending the DC measurement signal to the solenoid valve, and after a first period of time, performing voltage sampling on the solenoid valve again to obtain multiple DC voltage sampling values;

[0037] S316: Filter out the maximum value and the minimum value from all the DC voltage sampling values ​​obtained, and calculate the average value of the maximum value and the minimum value, which is the normal state voltage V z , calculate the absolute difference between the maximum value and the average value, which is the first threshold.

[0038] Technical effects and advantages of the present invention:

[0039] 1. This invention determines the solenoid valve's engagement state by simply measuring its voltage under a pulsed measurement signal, and determines the reason why the solenoid valve is not engaged or is not fully engaged by measuring its voltage under a DC measurement signal. This effectively identifies the solenoid valve's fault type and improves maintenance efficiency. Furthermore, the computational complexity is minimal, eliminating the need for a high-performance processor to analyze solenoid valve fault types, effectively reducing production and operating costs.

[0040] 2. The electromagnetic valve fault analysis and detection method provided by the present invention can be applied not only to gas alarms, but also to other scenarios where electromagnetic valves are used. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is an overall logic diagram of the solenoid valve fault analysis method provided by the present invention.

[0042] Figure 2 This is an overall logic diagram of the solenoid valve fault analysis method provided in Example 1 of the present invention.

[0043] Figure 3 This is a flow chart for monitoring the daily working status of the solenoid valve provided by the present invention.

[0044] Figure 4 This is a schematic diagram of the solenoid valve engagement state determination process provided in the second embodiment of the present invention. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0046] It should be noted that the numbering of all steps included in the present invention is only for the convenience of identifying each step, and does not limit the execution order of each step. The execution order of each step should be determined based on the content included in each step and the meaning of the context.

[0047] When the current within a solenoid valve's coil fluctuates dramatically, the coil's inductive reactance increases. The position of the valve core significantly influences the magnitude of the coil's inductive reactance. Therefore, the position of the solenoid valve core can be determined by measuring the solenoid valve coil's inductive reactance or the solenoid valve's voltage. For example, with some solenoid valves, when the solenoid valve is engaged, the valve core is inserted into the coil, increasing the coil's inductive reactance. When the solenoid valve is not engaged, the valve core is positioned outside the coil, decreasing the coil's inductive reactance. Furthermore, the further the valve core is inserted into the coil, the greater the coil's inductive reactance. Therefore, the coil's inductive reactance varies with the position of the valve core. Of course, the coil's inductive reactance for solenoid valves of different structures does not necessarily increase as the valve core becomes more engaged; it may also decrease.

[0048] Based on the above analysis, reference Figure 1 The embodiment of the present invention provides a method for fault analysis of a solenoid valve based on pulse control technology, which aims to monitor the state of the solenoid valve and analyze the fault type during daily use. Specifically, the method includes the following steps:

[0049] S1, send a pulse measurement signal to the solenoid valve and obtain the pulse measurement voltage V of the solenoid valve P ;

[0050] S2, measure the voltage V according to the pulse P Determine the closing state of the solenoid valve;

[0051] S3. If the solenoid valve is not closed or is not closed properly, a DC measurement signal is sent to the solenoid valve to obtain the DC measurement voltage V of the solenoid valve. D , according to the DC measurement voltage V D Determine the fault type of the solenoid valve.

[0052] The above method will be further described below with reference to specific embodiments.

[0053] Example 1

[0054] refer to Figure 2 After the gas alarm is installed and the solenoid valve is connected, power on the system and initialize it. Perform the following steps:

[0055] S21, set the solenoid valve to the non-attractive state, send a pulse measurement signal to the solenoid valve, and obtain the non-attractive state voltage V a Set the solenoid valve to the closed state, send the pulse measurement signal to the solenoid valve, and obtain the closed state voltage V b ;

[0056] S311, set the solenoid valve to an open circuit state, send a DC measurement signal to the solenoid valve, and obtain the open circuit state voltage V k , set the solenoid valve to short-circuit state, send a DC measurement signal to the solenoid valve, and obtain the short-circuit state voltage V d , set the solenoid valve to normal state, send a DC measurement signal to the solenoid valve, and obtain the normal state voltage V z .

[0057] Specifically, in step S311, the short-circuit state voltage V d The process also includes:

[0058] S312, changing the short-circuit position of the solenoid valve multiple times, sending a DC measurement signal to the solenoid valve, and obtaining multiple short-circuit measurement voltages;

[0059] S313, filter out the minimum value from all short-circuit measurement voltages, which is the short-circuit state voltage V d .

[0060] Specifically, the normal state voltage V z The process also includes:

[0061] S314, setting the solenoid valve to a non-engaged state, continuously sending a DC measurement signal to the solenoid valve, and after a first period of time, sampling the voltage of the solenoid valve to obtain multiple DC voltage sampling values;

[0062] S315, setting the solenoid valve to a closed state, continuously sending a DC measurement signal to the solenoid valve, and after a first period of time, sampling the voltage of the solenoid valve again to obtain multiple DC voltage sampling values;

[0063] S316: Filter out the maximum and minimum values ​​from all the DC voltage sampling values, and calculate the average value of the maximum and minimum values, which is the normal state voltage V z , calculate the absolute difference between the maximum value and the average value, which is the first threshold.

[0064] The solenoid valve coil generates inductive reactance when the current changes. Therefore, the solenoid valve voltage is unstable during the initial power-on phase. The solenoid valve voltage should be sampled after the first time the voltage stabilizes. The specific value of the first time depends on the solenoid valve model and the specific installation location.

[0065] When the gas detector detects a gas leak or other situation that requires shutting down the gas pipeline, it sends a pull-in command to the solenoid valve and waits for the solenoid valve to complete the pull-in action. For example, after sending the pull-in command to the solenoid valve for 3 seconds, it is considered that the solenoid valve has completed the pull-in action and begins to judge the pull-in status of the solenoid valve:

[0066] S1, send a pulse measurement signal to the solenoid valve and obtain the pulse measurement voltage V of the solenoid valve P ;

[0067] Since the working status of the solenoid valve needs to be regularly checked during daily use, the above steps can be periodically executed by a pre-set program to confirm the energized state of the solenoid valve and promptly detect open circuit and short circuit faults of the solenoid valve to ensure timely maintenance of the solenoid valve.

[0068] like Figure 3 As shown, in daily use, a pulse measurement signal is periodically sent to the solenoid valve to obtain the pulse measurement voltage V of the solenoid valve. P ;

[0069] The pulse measurement voltage V P and the open circuit voltage V k and short-circuit voltage V d Compare and determine whether the solenoid valve has an open circuit or short circuit fault;

[0070] If the solenoid valve has neither an open circuit fault nor a short circuit fault, the closed state of the solenoid valve is determined.

[0071] Pulse measurement voltage V P It can be obtained through step S11:

[0072] S11, continuously send pulse measurement signals to the solenoid valve, and after the first time, perform voltage sampling on the solenoid valve to obtain multiple pulse voltage sampling values, and calculate the average value of all pulse voltage sampling values, which is the pulse measurement voltage V P .

[0073] Then judge the closing state of the solenoid valve:

[0074] S2, measure the voltage V according to the pulse P Determine the closing state of the solenoid valve;

[0075] S22, calculate the status judgment voltage V1:

[0076] S23, if And V a >V b ,or And V a ≤Vb , the solenoid valve is in the non-attractive state. And V a ≤V b ,or And V a >V b , the solenoid valve is in the energized state.

[0077] When the solenoid valve is judged to be in the non-engaged state, the fault type of the solenoid valve is analyzed:

[0078] S3. If the solenoid valve is not closed or is not closed properly, a DC measurement signal is sent to the solenoid valve to obtain the DC measurement voltage V of the solenoid valve. D , according to the DC measurement voltage V D Determine the fault type of the solenoid valve.

[0079] Specifically, determine the fault type of the solenoid valve through the following steps:

[0080] S31, obtain the open circuit state voltage V k , short circuit voltage V d And the normal state voltage V z ;

[0081] S32, calculate the state judgment voltage V1: V1=|V D -V z |;

[0082] S33, if V D <V k , then the solenoid valve is open circuit, if V D >V d , the solenoid valve has a short circuit; if the state judgment voltage V1 is less than or equal to the first threshold, the solenoid valve has a mechanical failure; if the state judgment voltage V1 is greater than the first threshold, the solenoid valve has a coil failure.

[0083] There are many reasons why a solenoid valve may not engage properly. For example, a partial short circuit or open circuit in the coil winding may cause a decrease in the number of turns actually involved in generating the induced magnetic field, reducing the strength of the generated magnetic field and preventing the valve from engaging. Alternatively, the valve core may become stuck due to corrosion, rust, impurities, or damage, preventing the valve from engaging.

[0084] When the winding of the solenoid valve coil has a partial short circuit or open circuit, the voltage of the coil will deviate from the normal value when DC power is applied. When the solenoid valve core cannot move due to mechanical failure, the voltage of the coil when DC power is applied is still within the normal range. Therefore, by measuring the voltage value of the solenoid valve under the DC measurement signal, it can be determined whether the reason why the solenoid valve cannot be fully engaged is a coil failure or a mechanical failure.

[0085] Example 2

[0086] When the solenoid valve core fails to close due to coil or mechanical reasons, the pulse measurement voltage V P It will be between the un-attracted state voltage V a And the pull-in state voltage V b Therefore, simply classifying the solenoid valve's engagement state as engaged or not engaged can lead to misjudgment. In the event of a combustible gas leak, a solenoid valve that is not fully engaged can prevent the gas source from being shut off, leading to serious consequences. Therefore, it is necessary to improve the above judgment steps to determine whether the solenoid valve core is fully engaged.

[0087] Considering that the impedance of the solenoid valve coil is not a stable fixed value, but fluctuates within a fixed range, the solenoid valve's energized state is determined by the energized state voltage range, the non-energized state voltage range, and the partially energized state voltage range. The specific steps are as follows:

[0088] S24. When the system is initialized, the solenoid valve is set to the unengaged state, a pulse measurement signal is sent to the solenoid valve to obtain the unengaged state voltage range, the solenoid valve is set to the engaged state, a pulse measurement signal is sent to the solenoid valve to obtain the engaged state voltage range;

[0089] S25, constructing a voltage interval for insufficient energization based on the voltage interval in the unenergized state and the voltage interval in the energized state;

[0090] S26, measure the voltage V according to the pulse P The position of the solenoid valve determines the closing state of the solenoid valve.

[0091] refer to Figure 4 , when the pulse measurement voltage V P When the voltage falls within the pull-in state range, the solenoid valve is judged to be in the pull-in state. P When the voltage falls within the non-attractive state range, the solenoid valve is judged to be in the non-attractive state. P When the voltage falls within the under-attractive voltage range, the solenoid valve is determined to be in an under-attractive state.

[0092] Specifically, the voltage range in the non-energized state is obtained by the following steps:

[0093] S241, set the solenoid valve to the non-engaged state, continue to send the pulse measurement signal to the solenoid valve, after a first time, perform voltage sampling on the solenoid valve, obtain multiple pulse voltage sampling values, and select the maximum value V from all the pulse voltage sampling values. a 'With the minimum value V a , construct the voltage range of the non-attracted state.

[0094] Minimum V a It can be used as the non-attractive state voltage V used in the first embodiment. a .

[0095] The process of obtaining the voltage range of the pull-in state is the same:

[0096] S242, setting the solenoid valve to the energized state, continuously sending the pulse measurement signal to the solenoid valve, sampling the voltage of the solenoid valve after the first time, obtaining multiple pulse voltage sampling values, and screening out the maximum value V from all the pulse voltage sampling values. b 'With the minimum value V b , construct the voltage range of the attracted state.

[0097] Minimum V b It can be used as the pull-in state voltage V used in the first embodiment. b .

[0098] When the solenoid valve is in an open circuit state or a short circuit state, it will also cause the solenoid valve to fail to engage normally. In both the open circuit state and the short circuit state, since current no longer flows through the solenoid valve coil, the solenoid valve voltage measured under the pulse measurement signal and the solenoid valve voltage measured under the DC measurement signal will not differ significantly. For example, in the open circuit state, the solenoid valve voltage under the pulse measurement signal or the DC measurement signal is very small. In the short circuit state, the solenoid valve voltage under the pulse measurement signal or the DC measurement signal is very large. In step S241, the solenoid valve voltage is sampled in the normal connected state. Therefore, the obtained non-engaged state voltage interval is only used to determine whether the solenoid valve coil is not engaged when in the normal state.

[0099] Based on the above analysis, reference Figure 4 , you can take the following steps to obtain the voltage range of the non-attractive state:

[0100] S243, filter out the maximum and minimum values ​​from all pulse voltage sampling values, and combine them with the short-circuit state voltage V d and the open circuit voltage V k Construct the voltage range of the un-attracted state.

[0101] Of course, the voltage V can also be measured according to the pulse in step S26. P When judging the closing state of the solenoid valve by the position of P If it is not in any voltage range, the pulse measurement voltage V P and the short-circuit voltage V d and the open circuit voltage V k For comparison, if the pulse measurement voltage V P Less than the open circuit voltage V kOr greater than the short-circuit voltage V d , the solenoid valve is not closed.

[0102] If the unattracted state voltage interval constructed in step S243 is used, then when constructing the unattracted state voltage interval subsequently, only the maximum and minimum values ​​of the pulse voltage sampling values ​​obtained when sampling the voltages in the attracted state and the unattracted state should be considered.

[0103] Therefore, based on step S241, the voltage interval for insufficient pull-in is constructed by the following steps:

[0104] S251. Determine whether the maximum value of the voltage interval in the energized state is greater than the maximum value of the voltage interval in the unenergized state. If so, construct a voltage interval for insufficient energization based on the minimum value of the voltage interval in the energized state and the maximum value of the voltage interval in the unenergized state. If not, construct a voltage interval for insufficient energization based on the maximum value of the voltage interval in the energized state and the minimum value of the voltage interval in the unenergized state.

[0105] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for fault analysis of a solenoid valve based on pulse control technology, characterized in that: The following steps are involved: S1. Send a pulse measurement signal to the solenoid valve and obtain the pulse measurement voltage V of the solenoid valve P ; S2, measuring the voltage V according to the pulse P Determining the closed state of the solenoid valve; S3: If the solenoid valve is not closed or is not closed properly, a DC measurement signal is sent to the solenoid valve to obtain the DC measurement voltage V of the solenoid valve. D , according to the DC measurement voltage V D Determine the fault type of the solenoid valve; the fault type of the solenoid valve is determined by the following steps: S31, obtain the open circuit state voltage V k , short circuit voltage V d And the normal state voltage V z ; S32, calculate the state judgment voltage V1: V1=|V D -V z |; S33, if V D <V k , then the solenoid valve is open circuit, if V D >V d , the solenoid valve has a short circuit; if the state judgment voltage V1 is less than or equal to a first threshold, the solenoid valve has a mechanical failure; if the state judgment voltage V1 is greater than the first threshold, the solenoid valve has a coil failure.

2. The method for fault analysis of a solenoid valve based on pulse control technology according to claim 1, characterized in that: The closing state of the solenoid valve is determined by the following steps: S21, when the system is initialized, the solenoid valve is set to the non-attractive state, the pulse measurement signal is sent to the solenoid valve, and the non-attractive state voltage V is obtained. a , set the solenoid valve to the energized state, send the pulse measurement signal to the solenoid valve, and obtain the energized state voltage V b ; S22, calculate the status judgment voltage V1: S23, if And V a >V b ,or And V a <V b , the solenoid valve is in the non-attractive state. And V a <V b ,or And V a >V b , the solenoid valve is in the attracted state.

3. The method for fault analysis of a solenoid valve based on pulse control technology according to claim 1, characterized in that: The pulse measurement voltage V P Obtain it by following these steps: S11, continuously send a pulse measurement signal to the solenoid valve, and after a first period of time, perform voltage sampling on the solenoid valve to obtain multiple pulse voltage sampling values, and calculate the average value of all the pulse voltage sampling values, which is the pulse measurement voltage V P .

4. The method for fault analysis of a solenoid valve based on pulse control technology according to claim 1, characterized in that: The closing state of the solenoid valve is determined by the following steps: S24. When the system is initialized, the solenoid valve is set to an unengaged state, the pulse measurement signal is sent to the solenoid valve, and a voltage interval of the unengaged state is obtained; the solenoid valve is set to an engaged state, the pulse measurement signal is sent to the solenoid valve, and a voltage interval of the engaged state is obtained; S25, constructing a voltage interval for insufficient engagement according to the voltage interval in the unengaged state and the voltage interval in the engaged state; The voltage range of the non-attractive state is constructed by the following steps: S251, determining whether the maximum value of the engaged state voltage interval is greater than the maximum value of the unengaged state voltage interval; if so, constructing the unengaged voltage interval based on the minimum value of the engaged state voltage interval and the maximum value of the unengaged state voltage interval; if not, constructing the unengaged voltage interval based on the maximum value of the engaged state voltage interval and the minimum value of the unengaged state voltage interval; S26, measuring the voltage V according to the pulse P The position of the solenoid valve is used to determine the closed state of the solenoid valve.

5. The method for fault analysis of a solenoid valve based on pulse control technology according to claim 4, characterized in that: The voltage interval in the non-energized state is obtained by the following steps: S241. Continuously send the pulse measurement signal to the solenoid valve, and after a first period of time, perform voltage sampling on the solenoid valve to obtain a plurality of pulse voltage sampling values, filter out the maximum and minimum values ​​from all the pulse voltage sampling values, and construct the non-engaged state voltage interval.

6. The method for fault analysis of a solenoid valve based on pulse control technology according to claim 1, characterized in that: The open circuit state voltage V k , short circuit voltage V d And the normal state voltage V z Obtain it by following these steps: S311: When the system is initialized, the solenoid valve is set to an open circuit state, the DC measurement signal is sent to the solenoid valve, and the open circuit state voltage V is obtained. k , set the solenoid valve to a short-circuit state, send the DC measurement signal to the solenoid valve, and obtain the short-circuit state voltage V d , set the solenoid valve to a normal state, send the DC measurement signal to the solenoid valve, and obtain the normal state voltage V z .

7. The method for fault analysis of a solenoid valve based on pulse control technology according to claim 6, characterized in that: Get the short-circuit voltage V d The process also includes: S312, changing the short-circuit position of the solenoid valve multiple times, sending the DC measurement signal to the solenoid valve, and obtaining multiple short-circuit measurement voltages; S313, filter out the minimum value from all the short-circuit measurement voltages, which is the short-circuit state voltage V d .

8. The method for fault analysis of a solenoid valve based on pulse control technology according to claim 1, characterized in that: The normal state voltage V z And the first threshold is obtained by the following steps: S314: When the system is initialized, the solenoid valve is set to a non-engaged state, the DC measurement signal is continuously sent to the solenoid valve, and after a first period of time, the voltage of the solenoid valve is sampled to obtain a plurality of DC voltage sampling values; S315, setting the solenoid valve to an engaged state, continuously sending the DC measurement signal to the solenoid valve, and after a first period of time, performing voltage sampling on the solenoid valve again to obtain multiple DC voltage sampling values; S316: Filter out the maximum value and the minimum value from all the DC voltage sampling values ​​obtained, and calculate the average value of the maximum value and the minimum value, which is the normal state voltage V z , calculate the absolute difference between the maximum value and the average value, which is the first threshold.

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