An engine exhaust particulate matter detection method, device and system

Abstract

This invention relates to the technical field of exhaust gas detection, specifically to a method, device, and system for detecting particulate matter in engine exhaust gas. The method includes: acquiring a main measurement signal from a main channel and a secondary measurement signal from a secondary channel, wherein a trap for capturing particulate matter is installed in the secondary channel; filtering signal interference in the main measurement signal based on the secondary measurement signal to obtain an initial particulate matter signal; attenuating and recovering the initial particulate matter signal according to the deposition coefficients corresponding to the two channels to obtain a target particulate matter signal, wherein the deposition coefficients characterize the degree to which the impedance of the measurement signal acquisition component changes due to exhaust gas deposition; and performing exhaust gas particulate matter detection based on the target particulate matter signal to obtain a detection result. This invention can improve the accuracy of detecting the mass concentration of particulate matter in natural gas engine exhaust gas.

Description

Technical Field

[0001] This invention relates to the technical field of exhaust gas detection, specifically to a method, equipment, and system for detecting particulate matter in engine exhaust. Background Technology

[0002] Natural gas engines have gained widespread use due to their low-carbon, clean, and energy-efficient advantages. However, under conditions such as cold starts, transient operating conditions, high loads, and the involvement of lubricating oil in combustion, natural gas engines still produce a large proportion of nanoscale nucleoside particles, posing a potential impact on human health. Therefore, it is necessary to test the particulate matter in the exhaust of natural gas engines to assess whether their emissions meet standards.

[0003] In existing technologies, the charge method is often used for exhaust gas detection in natural gas engines. The basic principle is as follows: particulate matter in the exhaust gas is passed through a high-voltage discharge zone or a naturally charged zone. After the particulate matter carries a charge, it flows through a ring-shaped induction electrode. The weak current signal induced on the electrode has a certain positive correlation with the mass concentration of particulate matter. By detecting the current signal induced on the electrode and performing certain numerical conversions, the mass concentration of particulate matter in the exhaust gas can be calculated.

[0004] In practice, it was found that the mass concentration measured based on the above process was generally lower than the actual mass concentration. Summary of the Invention

[0005] The purpose of this invention is to provide a method, device, and system for detecting particulate matter in engine exhaust, which solves the technical problem of low accuracy in detecting the mass concentration of particulate matter in the exhaust of natural gas engines in the prior art.

[0006] In a first aspect, one embodiment of the present invention provides a method for detecting particulate matter in engine exhaust gas, the method comprising: Acquire the main measurement signal of the main channel and the slave measurement signal of the slave channel, wherein the main channel and the slave channel are arranged adjacent to each other, the channel structure of the main channel and the channel structure of the slave channel are the same, and the slave channel is provided with a trap for capturing particulate matter, and the signal acquisition time of the slave measurement signal is matched with the working time of the trap; Based on the filtering of signal interference in the main measurement signal from the measurement signal, an initial particulate matter signal is obtained; Based on the deposition coefficients corresponding to the dual channels, the initial particulate matter signal is attenuated and recovered to obtain the target particulate matter signal. The deposition coefficient is used to characterize the degree to which the impedance of the measurement signal acquisition component changes due to the effect of exhaust gas deposition. The deposition coefficient is determined based on the test results of the dual-channel current excitation test. The test current of the current excitation test is a preset value. The measurement signal acquisition component is used to acquire the main measurement signal or the slave measurement signal. Based on the target particulate matter signal, exhaust particulate matter is detected to obtain the detection results.

[0007] In some embodiments, the operating period of the trap includes the signal acquisition period of the measured signal, and the operating duration of the trap is longer than the signal acquisition duration corresponding to the measured signal.

[0008] In some embodiments, the step of obtaining the deposition coefficient corresponding to the dual channels includes: Based on the experimental results of the dual-channel current excitation test, the test current and excitation response voltage are obtained; Calculate the ratio of the excitation response voltage to the test current to obtain the test impedance; The difference between the test impedance and the preset reference impedance is analyzed to obtain the deposition coefficient corresponding to the dual channels, wherein the reference impedance is the calibration impedance of the measurement signal acquisition component.

[0009] In some embodiments, the step of analyzing the difference between the test impedance and a preset reference impedance to obtain the deposition coefficient corresponding to the dual channels includes: Calculate the absolute difference between the test impedance and the preset reference impedance to obtain the impedance change value; When the impedance change value is greater than or equal to the change threshold, the preset coefficient extreme value is determined as the deposition coefficient corresponding to the dual channel, and an abnormal prompt message indicating that the measurement signal acquisition component has a sensing abnormality is output. The change threshold is the product of the reference impedance and the coefficient extreme value, and the coefficient extreme value is greater than 0.6 and less than 1. If the impedance change value is less than the change threshold, the ratio of the impedance change value to the reference impedance is determined as the deposition coefficient corresponding to the dual channel.

[0010] In some embodiments, the step of attenuating and recovering the initial particulate matter signal based on the deposition coefficients corresponding to the dual channels to obtain the target particulate matter signal includes: When the acquisition cycle count of the main measurement signal and the slave measurement signal is less than or equal to the count threshold, the initial particulate matter signal is attenuated and recovered according to the deposition coefficient corresponding to the dual channels to obtain the target particulate matter signal; If the number of acquisition cycles is greater than the number of counts, the deposition coefficient corresponding to the dual channels is reduced according to the difference between the number of acquisition cycles and the number of counts to obtain a correction coefficient. The initial particulate matter signal is then attenuated and recovered according to the correction coefficient to obtain the target particulate matter signal.

[0011] In some embodiments, the step of reducing the deposition coefficient corresponding to the dual channels based on the difference between the acquisition cycle count and the count threshold to obtain a correction coefficient includes: Calculate the difference between the acquisition cycle count and the count threshold to obtain the count difference; The product of the count difference and a preset rate decay factor is calculated to obtain the rate decay value, wherein the rate decay factor is less than 0.01; The rate attenuation value is numerically converted to obtain a coefficient correction value, wherein the sum of the coefficient correction value and the rate attenuation value is 1; Calculate the product of the coefficient correction value and the deposition coefficient corresponding to the dual channels to obtain the real-time coefficient for the current acquisition cycle; Based on the real-time coefficient of the current acquisition cycle and the real-time coefficient or deposition coefficient of the N-1 acquisition cycles prior to the current acquisition cycle, coefficient smoothing is performed to obtain the correction coefficient of the current acquisition cycle, where N is the counting threshold.

[0012] In some embodiments, the step of performing coefficient smoothing based on the real-time coefficient of the current acquisition cycle and the real-time coefficients or deposition coefficients of the N-1 acquisition cycles prior to the current acquisition cycle to obtain the correction coefficient of the current acquisition cycle includes: The correction coefficient for the current acquisition cycle is obtained by weighting the real-time coefficient of the current acquisition cycle with the real-time coefficients or deposition coefficients of the N-1 acquisition cycles prior to the current acquisition cycle. The coefficient calculation weight of the corresponding acquisition cycle is positively correlated with the time domain priority of the corresponding acquisition cycle. The time domain priority is used to indicate the time domain distance between the corresponding acquisition cycle and the current acquisition cycle.

[0013] In some embodiments, the deposition coefficient is positively correlated with the signal strength of the target particulate signal.

[0014] Secondly, another embodiment of the present invention provides an engine exhaust particulate matter detection device, comprising: a processor, a memory, and a program stored in the memory and executable on the processor, wherein the program, when executed by the processor, implements the steps of the engine exhaust particulate matter detection method as described in the first aspect.

[0015] Thirdly, another embodiment of the present invention also provides an engine exhaust particulate matter detection system, comprising: The signal acquisition module is used to acquire the main measurement signal of the main channel and the slave measurement signal of the slave channel. The main channel and the slave channel are arranged adjacent to each other. The channel structure of the main channel and the channel structure of the slave channel are the same. The slave channel is provided with a trap for capturing particulate matter. The signal acquisition time of the slave measurement signal is matched with the working time of the trap. An interference filtering module is used to filter signal interference in the main measurement signal based on the secondary measurement signal to obtain an initial particulate matter signal; The attenuation recovery module is used to attenuate and recover the initial particulate matter signal according to the deposition coefficients corresponding to the dual channels to obtain the target particulate matter signal. The deposition coefficient is used to characterize the degree of change in the impedance of the measurement signal acquisition component due to the effect of exhaust gas deposition. The deposition coefficient is determined based on the test results of the dual-channel current excitation test. The test current of the current excitation test is a preset value. The measurement signal acquisition component is used to acquire the main measurement signal or the slave measurement signal. The exhaust gas detection module is used to detect exhaust gas particulate matter based on the target particulate matter signal and obtain the detection result.

[0016] The present invention has the following beneficial effects: By setting up dual channels with adjacent locations and identical structures, the main and secondary channels are placed in the same exhaust gas environment. Then, utilizing the difference in whether or not a filter is installed in the main and secondary channels, the main channel faces exhaust gas containing particulate matter, while the secondary channel faces exhaust gas without particulate matter. This allows for the acquisition of a main measurement signal generated by the combined effects of particulate matter and environmental interference, and a secondary measurement signal generated solely by environmental interference. The secondary measurement signal is then used to filter out signal interference in the main measurement signal, yielding an initial particulate matter signal that roughly reflects the mass concentration of exhaust gas particulate matter. A deposition coefficient is obtained through current excitation experiments conducted within the dual channels. This deposition coefficient characterizes the passivation of the measurement sensitivity of the signal acquisition component due to exhaust gas deposits. Based on this, the initial particulate matter signal is attenuated and recovered to compensate for hardware interference caused by exhaust gas deposits, resulting in a target particulate matter signal that accurately reflects the mass concentration of exhaust gas particulate matter. Finally, exhaust gas particulate matter detection is performed, bringing the measured mass concentration closer to the actual mass concentration and improving the accuracy of particulate matter mass concentration detection in natural gas engine exhaust. Attached Figure Description

[0017] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic flowchart of a method for detecting particulate matter in engine exhaust provided by an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of an engine exhaust particulate matter detection system provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of an engine exhaust particulate matter detection device provided in an embodiment of the present invention. Detailed Implementation

[0019] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of an engine exhaust particulate matter detection method, device, and system proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] The following description, in conjunction with the accompanying drawings, details the specific solution of the engine exhaust particulate matter detection method, equipment, and system provided by the present invention.

[0022] In one embodiment, such as Figure 1 As shown, the present invention provides a method for detecting particulate matter in engine exhaust, the method comprising: Step S1: Obtain the master measurement signal of the master channel and the slave measurement signal of the slave channel.

[0023] The main channel and the slave channel are arranged adjacent to each other. The channel structure of the main channel and the channel structure of the slave channel are the same. The slave channel is equipped with a trap for capturing particulate matter. The signal acquisition time of the slave measurement signal is matched with the working time of the trap.

[0024] In this invention, both the main channel and the slave channel are charge induction channels located in the exhaust emission area / exhaust gas detection area of ​​the natural gas engine. The main channel and the slave channel are equipped with measurement signal acquisition components and charged structures that are completely identical in structure, size and material, so as to obtain the corresponding main measurement signal and slave measurement signal through the measurement signal acquisition components. Specifically, this invention uses a ring induction electrode as the measurement signal acquisition component, and the discharge voltage of the charged structure is between 5kV and 15kV.

[0025] The difference between the main channel and the secondary channel is that a trap is installed at the inlet or front end of the secondary channel to fully capture particulate matter in the exhaust gas. In this invention, a controllable electrostatic trap is used as the trap.

[0026] An excitation structure for performing current excitation tests is also provided. This excitation structure includes two output terminals, one located in the main channel and the other in the slave channel. The two output terminals synchronously apply AC excitation signals to the measurement signal acquisition components of the main and slave channels to obtain the corresponding test results. In application, the real-time output frequency f (unit: kHz) and excitation voltage U (unit: V) corresponding to the two output terminals of the excitation structure are recorded to ensure that the excitation parameters of the main and slave channels are completely consistent, thereby avoiding test errors caused by differences in excitation parameters. Furthermore, the output frequency of the excitation structure is 100kHz-1MHz, and the output frequency can be dynamically adjusted according to engine operating conditions. For example, during transient engine operating conditions (such as acceleration and deceleration), the output frequency is increased to 500kHz-1MHz to enhance the accuracy of the test results; during steady-state operating conditions, an output frequency of 100kHz-300kHz is used to reduce energy consumption and improve measurement stability.

[0027] Analysis revealed that in the exhaust gas environment, the measurement signals of the measurement signal acquisition component are mainly affected by both particulate matter and environmental interference factors. Among these, the composition of environmental interference factors is complex and variable. If each environmental interference item is processed individually, it is difficult to avoid the problem of missing environmental interference items. To address this issue, this invention utilizes a dual-channel setup of a main channel and a slave channel, starting from the more controllable particulate matter side. By using a trap, the main measurement signal generated by the combined effects of particulate matter and environmental interference factors is acquired on the main channel side, while the slave measurement signal generated solely by environmental interference factors is simultaneously acquired on the slave channel side. The slave measurement signal is then used to filter signal interference in the main measurement signal, thereby effectively suppressing signal measurement errors caused by environmental interference.

[0028] In this invention, matching the signal acquisition time of the measured signal with the working time of the trap specifically means that the working time of the trap includes the signal acquisition time of the measured signal, and the working time of the trap is longer than the signal acquisition time corresponding to the measured signal.

[0029] This setup effectively shields particulate matter from interfering with the acquisition of measurement signals, ensuring the accuracy and reliability of the acquired measurement signals.

[0030] In application, to ensure environmental consistency between the main channel and the slave channel, and to reduce the energy consumption of the trap, the trap is set to operate periodically. It should be understood that the main measurement signal and the slave measurement signal will be collected multiple times periodically. Similarly, the trap will also be turned on and off periodically. Before the slave measurement signal of the corresponding period is collected, the trap will be turned on in advance (e.g., 3-10 seconds in advance) to achieve sufficient capture of particulate matter in the exhaust gas. The trap will stop its operation in the current period only after the slave measurement signal of the corresponding period is collected. That is, the trap is turned on and off periodically according to the periodic operation of the measurement signal acquisition component of the slave channel.

[0031] That is, within each acquisition cycle, the start time of the trap is earlier than the start time of signal acquisition corresponding to the measurement signal, and the end time of the trap is later than the end time of signal acquisition corresponding to the measurement signal.

[0032] Specifically, the duration of a single acquisition cycle can be 5-30 seconds, and the interval between adjacent acquisition cycles can be 20-120 minutes.

[0033] In addition, to ensure the accuracy of the acquired master measurement signal and slave measurement signal, in the corresponding acquisition cycle, the average value of multiple measurement signals acquired by the master channel measurement signal acquisition component is used as the master measurement signal, and the average value of multiple measurement signals acquired by the slave channel measurement signal acquisition component is used as the slave measurement signal.

[0034] In this invention, the measurement signal is specifically a current signal acquired based on the corresponding ring-shaped induction electrode.

[0035] Step S2: Filter the signal interference in the main measurement signal based on the secondary measurement signal to obtain the initial particulate matter signal.

[0036] Specifically, the initial particulate matter signal can be obtained by subtracting the secondary measurement signal from the primary measurement signal.

[0037] It should be noted that the unburned gaseous hydrocarbons and trace amounts of oily components in the exhaust gas of natural gas engines will deposit and adhere to the surface of the measurement signal acquisition component when it flows through it. These sticky substances will accumulate and form a layer of organic insulating film with poor conductivity. This organic insulating film will block the charge conduction between charged particles and the sensing end of the acquisition component, reduce the charge capture and collection efficiency, and cause the initial particulate matter signal obtained in the aforementioned steps to still have a large deviation from the actual signal value.

[0038] To address this problem, the present invention obtains a deposition coefficient through a current excitation experiment conducted in a dual-channel environment. The deposition coefficient is used to characterize the passivation of the measurement sensitivity of the measurement signal acquisition component affected by exhaust gas deposits. Based on this, the initial particulate matter signal is attenuated and recovered to compensate for hardware interference caused by exhaust gas deposits, thereby obtaining a target particulate matter signal that accurately reflects the mass concentration of exhaust gas particulate matter.

[0039] Step S3: Based on the deposition coefficients corresponding to the dual channels, the initial particulate matter signal is attenuated and recovered to obtain the target particulate matter signal.

[0040] The deposition coefficient is used to characterize the degree to which the impedance of the measurement signal acquisition component changes due to the deposition of exhaust gas. The deposition coefficient is determined based on the test results of a dual-channel current excitation test, where the test current of the current excitation test is a preset value. The measurement signal acquisition component is used to acquire the main measurement signal or the slave measurement signal.

[0041] Specifically, the process of the dual-channel current excitation test is as follows: The excitation structure generates an excitation current according to the preset excitation parameters. The same excitation current (i.e., test current) is synchronously output to the main channel and the slave channel through two output terminals. The voltage data fed back by the measurement signal acquisition components of the main channel and the slave channel are collected respectively. The excitation current and voltage data are then combined to form the test results, thus completing one current excitation test.

[0042] In applications, the corresponding current excitation test can be completed during the time interval between two acquisition cycles.

[0043] In this invention, the step of obtaining the deposition coefficient corresponding to the dual channels includes: Based on the experimental results of the dual-channel current excitation test, the test current and excitation response voltage are obtained; Calculate the ratio of the excitation response voltage to the test current to obtain the test impedance; The difference between the test impedance and the preset reference impedance is analyzed to obtain the deposition coefficient corresponding to the dual channels, wherein the reference impedance is the calibration impedance of the measurement signal acquisition component.

[0044] It should be understood that the excitation response voltage is the average value of the voltage data fed back by the measurement signal acquisition component of the main channel and the measurement signal acquisition component of the secondary channel, respectively. The reference impedance can be obtained from the factory information of the measurement signal acquisition component, or determined by testing the actual impedance value exhibited by the measurement signal acquisition component in a clean environment without exhaust gas.

[0045] The step of analyzing the difference between the test impedance and the preset reference impedance to obtain the deposition coefficient corresponding to the dual channels includes: Calculate the absolute difference between the test impedance and the preset reference impedance to obtain the impedance change value; When the impedance change value is greater than or equal to the change threshold, the preset coefficient extreme value is determined as the deposition coefficient corresponding to the dual channel, and an abnormal prompt message indicating that the measurement signal acquisition component has a sensing abnormality is output. The change threshold is the product of the reference impedance and the coefficient extreme value, and the coefficient extreme value is greater than 0.6 and less than 1. If the impedance change value is less than the change threshold, the ratio of the impedance change value to the reference impedance is determined as the deposition coefficient corresponding to the dual channel.

[0046] In practical applications, as the organic insulating film thickens, the test impedance also increases accordingly. When the organic insulating film thickens to a certain extent, it will significantly interfere with the acquisition of the main measurement signal and the slave measurement signal. In this case, the acquired main measurement signal and slave measurement signal will have a large risk of distortion, which will affect the accuracy of the target particulate matter signal obtained in subsequent processing. However, this invention can identify the situation of excessively thick organic insulating film in a timely manner by changing the threshold setting, and use the output of abnormal prompt information to guide relevant personnel to deal with the organic insulating film covering the surface of the measurement signal acquisition component in a timely manner, while also indicating the possible error risk of the current output detection result.

[0047] In this invention, the extreme value of the coefficient is set to 0.78 based on experience. In application, the measurement signal acquisition component can be covered with organic insulating films of different thicknesses, and the difference between the actual measurement signal and the true measurement signal under the organic insulating film covering the measurement signal acquisition component of different thicknesses can be obtained. Then, among multiple differences, the difference that does not exceed the preset error value and corresponds to the organic insulating film with the largest thickness is determined as the target difference. Then, based on the preset impedance calibration curve, the impedance change corresponding to the target difference is obtained, and the ratio of the impedance change to the reference impedance is determined as the aforementioned extreme value of the coefficient. The aforementioned impedance calibration curve is used to reflect the numerical mapping relationship between the impedance change and the actual measurement signal.

[0048] The step of attenuating and recovering the initial particulate matter signal based on the deposition coefficients corresponding to the dual channels to obtain the target particulate matter signal includes: When the acquisition cycle count of the main measurement signal and the slave measurement signal is less than or equal to the count threshold, the initial particulate matter signal is attenuated and recovered according to the deposition coefficient corresponding to the dual channels to obtain the target particulate matter signal; If the number of acquisition cycles is greater than the number of counts, the deposition coefficient corresponding to the dual channels is reduced according to the difference between the number of acquisition cycles and the number of counts to obtain a correction coefficient. The initial particulate matter signal is then attenuated and recovered according to the correction coefficient to obtain the target particulate matter signal.

[0049] In application, it was found that the deposition thickness of the organic insulating film exhibits a non-linear variation. Specifically, the growth rate of the deposition thickness gradually slows down over time. To address this, this invention adaptively distinguishes between the early and late deposition stages of the organic insulating film by setting a counting threshold. In the early deposition stage, the calculated deposition coefficient is directly used to characterize the degree of interference of the organic insulating film on signal measurement. In the late deposition stage, the calculated deposition coefficient is reduced based on the current acquisition cycle count, and the correction coefficient is used to accurately characterize the degree of interference of the organic insulating film on signal measurement, thereby adapting to the non-linear variation of the deposition thickness of the organic insulating film in the late stage.

[0050] The above-mentioned acquisition cycle count can be understood as the count value of the cumulative acquisition operation frequency from the first acquisition cycle of the scheme implementation to the current acquisition cycle. For example, if the current acquisition cycle is the first acquisition cycle of the scheme implementation, the acquisition cycle count is 1, and so on. It should be noted that after the dual-channel collaborative detection scheme is completed once, the surface of the measurement signal acquisition components of the main channel and the slave channel needs to be cleaned.

[0051] The deposition coefficient is positively correlated with the signal strength of the target particulate matter signal. That is, the larger the deposition coefficient, the more severe the interference of the organic insulating film on the signal measurement, the more significant the attenuation of the initial particulate matter signal compared to the target particulate matter signal, and the larger the target particulate matter signal recovered based on the initial particulate matter signal.

[0052] Specifically, based on the deposition coefficients corresponding to the dual channels, the initial particulate matter signal is attenuated and recovered to obtain the target particulate matter signal. It can be represented as: In the above formula, This represents the number of acquisition cycles when the count is less than or equal to the counting threshold. Indicates the number of acquisition cycles. The main measurement signal acquired at that time, Indicates the number of acquisition cycles. The measurement signal acquired in time, Indicates the number of acquisition cycles. The initial particulate matter signal at that time, Indicates the number of acquisition cycles. The latest obtained sedimentation coefficient, The value is a positive integer and is less than or equal to the aforementioned counting threshold. Based on experience, the present invention sets the counting threshold to 5.

[0053] The step of reducing the deposition coefficient corresponding to the dual channels based on the difference between the acquisition cycle count and the count threshold to obtain the correction coefficient includes: Calculate the difference between the acquisition cycle count and the count threshold to obtain the count difference; The product of the count difference and a preset rate decay factor is calculated to obtain the rate decay value, wherein the rate decay factor is less than 0.01; The rate attenuation value is numerically converted to obtain a coefficient correction value, wherein the sum of the coefficient correction value and the rate attenuation value is 1; Calculate the product of the coefficient correction value and the deposition coefficient corresponding to the dual channels to obtain the real-time coefficient for the current acquisition cycle; Based on the real-time coefficient of the current acquisition cycle and the real-time coefficient or deposition coefficient of the N-1 acquisition cycles prior to the current acquisition cycle, coefficient smoothing is performed to obtain the correction coefficient of the current acquisition cycle, where N is the counting threshold.

[0054] For example, the coefficient correction value for the current acquisition period It can be represented as: in, This represents the aforementioned rate decay factor. This represents the number of acquisition cycles when the count exceeds the counting threshold. N represents the counting threshold. Based on experience, this invention sets the rate decay factor to 0.002.

[0055] It should be noted that the coefficient correction value for any acquisition period is limited to being greater than or equal to the limit threshold, which can be set to 0.1 based on experience.

[0056] Specifically, the step of smoothing the coefficients based on the real-time coefficients of the current acquisition cycle and the real-time coefficients or deposition coefficients of the N-1 acquisition cycles prior to the current acquisition cycle to obtain the correction coefficients for the current acquisition cycle includes: The correction coefficient for the current acquisition cycle is obtained by weighting the real-time coefficient of the current acquisition cycle with the real-time coefficients or deposition coefficients of the N-1 acquisition cycles prior to the current acquisition cycle. The coefficient calculation weight of the corresponding acquisition cycle is positively correlated with the time domain priority of the corresponding acquisition cycle. The time domain priority is used to indicate the time domain distance between the corresponding acquisition cycle and the current acquisition cycle.

[0057] In the above settings, the weighted calculation method is used to suppress the calculation interference caused by extreme values, making the calculated correction coefficients more accurate and reliable. The method of determining the coefficient calculation weight according to the time domain priority can amplify the numerical influence of recent real-time coefficients or sedimentation coefficients, and realize rapid tracking of the current working conditions.

[0058] In this invention, based on experience, the coefficient calculation weights for the current acquisition cycle and the N-1 acquisition cycles prior to it are set to 0.3, 0.25, 0.2, 0.15 and 0.1 respectively.

[0059] Step S4: Detect exhaust particulate matter based on the target particulate matter signal to obtain the detection result.

[0060] As mentioned above, the target particulate matter signal can represent the mass concentration of particulate matter in the exhaust gas. Therefore, the exhaust gas particulate matter detection performed in this invention is specifically as follows: the target particulate matter signal is compared with a preset threshold signal. If the target particulate matter signal is greater than or equal to the threshold signal, the detection result of non-compliance of exhaust gas emissions is output to prompt relevant personnel to carry out maintenance on the natural gas engine. If the target particulate matter signal is less than the threshold signal, the detection result of compliance of exhaust gas emissions is output.

[0061] In this invention, the threshold signal is empirically set to 2 (unit: mg / m³). 3 or μg / m 3 ).

[0062] In summary, this invention establishes two adjacent and identical channels, placing the main and secondary channels in the same exhaust gas environment. Utilizing the difference in whether or not a trap is installed in the main and secondary channels, the main channel faces exhaust gas containing particulate matter, while the secondary channel faces exhaust gas without particulate matter. This allows for the acquisition of a main measurement signal generated by the combined effects of particulate matter and environmental interference, and a secondary measurement signal generated solely by environmental interference. The secondary measurement signal is then used to filter out interference in the main measurement signal, yielding an initial particulate matter signal that roughly reflects the mass concentration of exhaust gas particulate matter. A deposition coefficient is obtained through current excitation experiments conducted within the dual channels. This deposition coefficient characterizes the passivation of the measurement sensitivity of the signal acquisition component due to exhaust gas deposits, and the initial particulate matter signal is attenuated and recovered to compensate for hardware interference caused by exhaust gas deposits. This results in a target particulate matter signal that accurately reflects the mass concentration of exhaust gas particulate matter. Finally, exhaust gas particulate matter detection is performed, bringing the measured mass concentration closer to the actual mass concentration and improving the accuracy of particulate matter mass concentration detection in natural gas engine exhaust.

[0063] In one embodiment, the present invention also provides an engine exhaust particulate matter detection system, such as... Figure 2 As shown, the engine exhaust particulate matter detection system 200 includes: The signal acquisition module 201 is used to acquire the main measurement signal of the main channel and the slave measurement signal of the slave channel. The main channel and the slave channel are arranged adjacent to each other. The channel structure of the main channel and the channel structure of the slave channel are the same. The slave channel is provided with a trap for capturing particulate matter. The signal acquisition time of the slave measurement signal is matched with the working time of the trap. Interference filtering module 202 is used to filter signal interference in the main measurement signal based on the secondary measurement signal to obtain an initial particulate matter signal; The attenuation recovery module 203 is used to attenuate and recover the initial particulate matter signal according to the deposition coefficients corresponding to the dual channels to obtain the target particulate matter signal. The deposition coefficient is used to characterize the degree of change of the impedance of the measurement signal acquisition component due to the effect of exhaust gas deposition. The deposition coefficient is determined based on the test results of the dual-channel current excitation test. The test current of the current excitation test is a preset value. The measurement signal acquisition component is used to acquire the main measurement signal or the slave measurement signal. The exhaust gas detection module 204 is used to detect exhaust gas particulate matter based on the target particulate matter signal and obtain the detection result.

[0064] It should be noted that the system provided in the above embodiments is only an example of the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the computer device can be divided into different functional modules to complete all or part of the functions described above. In addition, the engine exhaust particulate matter detection system and the engine exhaust particulate matter detection method embodiment provided in the above embodiments belong to the same concept, and their specific implementation process can be found in the method embodiment, which will not be repeated here.

[0065] This invention also provides an engine exhaust particulate matter detection device. Please refer to [link / reference]. Figure 3 The engine exhaust particulate matter detection device may include a processor 301, a memory 302, and a program 3021 stored in the memory 302 and capable of running on the processor 301.

[0066] When program 3021 is executed by processor 301, it can achieve the following: Figure 1 Any steps in the corresponding method embodiments and the achievement of the same beneficial effects will not be repeated here.

[0067] Those skilled in the art will understand that all or part of the steps of the methods described in the above embodiments can be implemented by hardware related to program instructions, and the program can be stored in a readable medium.

[0068] This invention also provides a readable storage medium storing a computer program, which, when executed by a processor, can perform the above-described functions. Figure 1 Any step in the corresponding method embodiment can achieve the same technical effect, and will not be repeated here to avoid repetition.

[0069] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

Claims

1. A method for detecting particulate matter in engine exhaust, characterized in that, The method includes: Acquire the main measurement signal of the main channel and the slave measurement signal of the slave channel, wherein the main channel and the slave channel are arranged adjacent to each other, the channel structure of the main channel and the channel structure of the slave channel are the same, and the slave channel is provided with a trap for capturing particulate matter, and the signal acquisition time of the slave measurement signal is matched with the working time of the trap; Based on the filtering of signal interference in the main measurement signal from the measurement signal, an initial particulate matter signal is obtained; Based on the deposition coefficients corresponding to the dual channels, the initial particulate matter signal is attenuated and recovered to obtain the target particulate matter signal. The deposition coefficient is used to characterize the degree to which the impedance of the measurement signal acquisition component changes due to the effect of exhaust gas deposition. The deposition coefficient is determined based on the test results of the dual-channel current excitation test. The test current of the current excitation test is a preset value. The measurement signal acquisition component is used to acquire the main measurement signal or the slave measurement signal. Based on the target particulate matter signal, exhaust particulate matter is detected to obtain the detection results.

2. The method for detecting particulate matter in engine exhaust according to claim 1, characterized in that, The operating period of the trap includes the signal acquisition period of the measured signal, and the operating duration of the trap is longer than the signal acquisition duration corresponding to the measured signal.

3. The method for detecting particulate matter in engine exhaust according to claim 1, characterized in that, The steps for obtaining the deposition coefficient corresponding to the dual channels include: Based on the experimental results of the dual-channel current excitation test, the test current and excitation response voltage are obtained; Calculate the ratio of the excitation response voltage to the test current to obtain the test impedance; The difference between the test impedance and the preset reference impedance is analyzed to obtain the deposition coefficient corresponding to the dual channels, wherein the reference impedance is the calibration impedance of the measurement signal acquisition component.

4. The method for detecting particulate matter in engine exhaust gas according to claim 3, characterized in that, The step of analyzing the difference between the test impedance and the preset reference impedance to obtain the deposition coefficient corresponding to the dual channels includes: Calculate the absolute difference between the test impedance and the preset reference impedance to obtain the impedance change value; When the impedance change value is greater than or equal to the change threshold, the preset coefficient extreme value is determined as the deposition coefficient corresponding to the dual channel, and an abnormal prompt message indicating that the measurement signal acquisition component has a sensing abnormality is output. The change threshold is the product of the reference impedance and the coefficient extreme value, and the coefficient extreme value is greater than 0.6 and less than 1. If the impedance change value is less than the change threshold, the ratio of the impedance change value to the reference impedance is determined as the deposition coefficient corresponding to the dual channel.

5. The method for detecting particulate matter in engine exhaust according to claim 1, characterized in that, The step of attenuating and recovering the initial particulate matter signal based on the deposition coefficients corresponding to the dual channels to obtain the target particulate matter signal includes: When the acquisition cycle count of the main measurement signal and the slave measurement signal is less than or equal to the count threshold, the initial particulate matter signal is attenuated and recovered according to the deposition coefficient corresponding to the dual channels to obtain the target particulate matter signal; If the number of acquisition cycles is greater than the number of counts, the deposition coefficient corresponding to the dual channels is reduced according to the difference between the number of acquisition cycles and the number of counts to obtain a correction coefficient. The initial particulate matter signal is then attenuated and recovered according to the correction coefficient to obtain the target particulate matter signal.

6. The method for detecting particulate matter in engine exhaust gas according to claim 5, characterized in that, The step of reducing the deposition coefficient corresponding to the dual channels based on the difference between the acquisition cycle count and the count threshold to obtain the correction coefficient includes: Calculate the difference between the acquisition cycle count and the count threshold to obtain the count difference; The product of the count difference and a preset rate decay factor is calculated to obtain the rate decay value, wherein the rate decay factor is less than 0.01; The rate attenuation value is numerically converted to obtain a coefficient correction value, wherein the sum of the coefficient correction value and the rate attenuation value is 1; Calculate the product of the coefficient correction value and the deposition coefficient corresponding to the dual channels to obtain the real-time coefficient for the current acquisition cycle; Based on the real-time coefficient of the current acquisition cycle and the real-time coefficient or deposition coefficient of the N-1 acquisition cycles prior to the current acquisition cycle, coefficient smoothing is performed to obtain the correction coefficient of the current acquisition cycle, where N is the counting threshold.

7. The method for detecting particulate matter in engine exhaust according to claim 6, characterized in that, The steps for obtaining the correction coefficient for the current acquisition cycle by smoothing the coefficients based on the real-time coefficients of the current acquisition cycle and the real-time coefficients or deposition coefficients of the N-1 acquisition cycles prior to the current acquisition cycle include: The correction coefficient for the current acquisition cycle is obtained by weighting the real-time coefficient of the current acquisition cycle with the real-time coefficients or deposition coefficients of the N-1 acquisition cycles prior to the current acquisition cycle. The coefficient calculation weight of the corresponding acquisition cycle is positively correlated with the time domain priority of the corresponding acquisition cycle. The time domain priority is used to indicate the time domain distance between the corresponding acquisition cycle and the current acquisition cycle.

8. The method for detecting particulate matter in engine exhaust according to any one of claims 1-7, characterized in that, The deposition coefficient is positively correlated with the signal strength of the target particulate matter signal.

9. An engine exhaust particulate matter detection device, characterized in that, include: A processor, a memory, and a program stored in the memory and executable on the processor, wherein the program, when executed by the processor, implements the steps of the engine exhaust particulate matter detection method as described in any one of claims 1 to 8.

10. An engine exhaust particulate matter detection system, characterized in that, include: The signal acquisition module is used to acquire the main measurement signal of the main channel and the slave measurement signal of the slave channel. The main channel and the slave channel are arranged adjacent to each other. The channel structure of the main channel and the channel structure of the slave channel are the same. The slave channel is provided with a trap for capturing particulate matter. The signal acquisition time of the slave measurement signal is matched with the working time of the trap. An interference filtering module is used to filter signal interference in the main measurement signal based on the secondary measurement signal to obtain an initial particulate matter signal; The attenuation recovery module is used to attenuate and recover the initial particulate matter signal according to the deposition coefficients corresponding to the dual channels to obtain the target particulate matter signal. The deposition coefficient is used to characterize the degree of change in the impedance of the measurement signal acquisition component due to the effect of exhaust gas deposition. The deposition coefficient is determined based on the test results of the dual-channel current excitation test. The test current of the current excitation test is a preset value. The measurement signal acquisition component is used to acquire the main measurement signal or the slave measurement signal. The exhaust gas detection module is used to detect exhaust gas particulate matter based on the target particulate matter signal and obtain the detection result.

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