An engine operating state monitoring method based on vibration signals

Abstract

The present invention relates to the technical field of engine condition monitoring, and in particular to an engine operating condition monitoring method based on vibration signals, including: collecting engine vibration data within a monitoring period, and synchronously recording engine load data and additional vibration data; preprocessing the additional vibration data, analyzing the environmental vibration state, constructing an engine main body vibration index based on the engine vibration data, and constructing a load threshold, thereby judging the vibration state of the engine main body, extracting the abnormal amplitude of the engine main body, and adjusting the judgment process of the vibration state of the engine main body, constructing a resonance model of the engine within the monitoring period to judge the actual operating state of the engine, and further determining the actual fault type of the engine; updating the engine speed alarm system based on the actual operating state of the engine. The present invention effectively improves the monitoring efficiency of the engine operating state based on vibration signals.

Description

Technical Field

[0001] The present invention relates to the technical field of engine condition monitoring, and particularly to an engine operating condition monitoring method based on vibration signals. Background Art

[0002] In recent years, with the development of sensor technology and data analysis methods, using vibration signals for mechanical fault diagnosis has become an effective method. However, there are still certain limitations in the existing technology in terms of vibration signal processing, feature extraction, and fault mode recognition, resulting in limited application effects.

[0003] Chinese Patent Publication No. CN118565836A discloses an automobile engine operation data monitoring system, including: a data acquisition module for real-time acquisition of engine operation data and environmental data, and also for acquiring engine parameter data; an environmental analysis module for analyzing abnormal working environment states; an operation monitoring module for analyzing the engine vibration state, analyzing the vibration change state within the monitoring period, and also analyzing abnormal vibration states; an adjustment and optimization module for adjusting the analysis process of the engine vibration state and optimizing the adjustment process of the engine vibration state based on the results; a combustion monitoring module for analyzing abnormal combustion states; and an abnormal alarm module for analyzing the engine operation state. It can be seen that when this invention monitors the engine, it comprehensively monitors the engine operation state considering the environment and vibration, without specifically analyzing the vibration signals of each engine component and the resonance effect between the engine and external vibrations, resulting in a problem of low analysis efficiency of vibration signals. At the same time, it lacks an analysis process for engine knock signals in the alpine environment, and there are inaccuracies in the monitoring of the engine operation state. Summary of the Invention

[0004] The purpose of the present invention is to provide an engine operating condition monitoring method based on vibration signals to solve at least one of the problems existing in the prior art.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] An engine operating condition monitoring method based on vibration signals, characterized by including:

[0007] Construct an engine main body vibration index based on the engine vibration data within the monitoring period, and construct a load threshold based on the engine load data, and then judge the engine main body vibration state based on the load threshold and the engine main body vibration index;

[0008] When the vibration state of the engine body is abnormal, extract the abnormal amplitude of the engine body, and combine the engine intake data to determine the knock amplitude of the engine during the monitoring period, and then adjust the judgment process of the vibration state of the engine body;

[0009] Integrate the vibration state of the engine body and the environmental vibration state during the monitoring period to construct a resonance model of the engine during the monitoring period to judge the actual operating state of the engine, and then determine the actual fault type of the engine.

[0010] Optionally, construct vibration factors for each local component of the engine based on the engine vibration data, and jointly construct the engine body vibration index with the vibration factors of each local component;

[0011] The specific process of constructing the vibration factors of each local component of the engine is as follows:

[0012] Construct the bearing vibration factor α(i), and set α(i)=Qv(i) / r(i)×Qσ(i);

[0013] Among them, Qv(i) represents the vibration frequency of the i-th bearing, r(i) represents the rotational speed of the i-th bearing, and Qσ(i) represents the standard deviation of the vibration amplitude of the i-th bearing;

[0014] Construct the piston vibration factor β(j), and set β(j)=Hv(j) / n(j)×Hσ(j);

[0015] Among them, n(j) represents the frequency of the j-th piston during the monitoring period, Hv(j) represents the vibration frequency of the j-th piston, and Hσ(j) represents the standard deviation of the vibration amplitude of the j-th piston;

[0016] The specific process of constructing the engine body vibration index is as follows:

[0017] ;

[0018] Among them, b1 is the bearing weight, b2 is the piston weight, ZP is the engine body vibration frequency, I is the number of bearings, and J is the number of pistons.

[0019] Optionally, construct a load threshold Y based on the load data during the monitoring period, and set Y=R / ZR; where R is the engine speed and ZR is the rotational speed of the transmission shaft;

[0020] The specific process of judging the vibration state of the engine body is as follows:

[0021] If Y×(1 - η) ≤ γ < Y×(1 + η), it is determined that the vibration state of the engine body during the monitoring period is normal; otherwise, it is determined that the vibration state of the engine body during the monitoring period is abnormal;

[0022] Among them, η is the offset coefficient, 0 < η < 0.3.

[0023] Optionally, calculate the coefficient of variation fb of the engine body amplitude and the mean value fE of the engine body amplitude, and set the abnormal amplitude threshold YF, where YF = fb × fE;

[0024] Compare the vibration amplitude of the engine body within the monitoring period with the abnormal amplitude threshold YF, and set the vibration amplitude of the engine body exceeding the abnormal amplitude YF as the abnormal amplitude of the engine body.

[0025] Optionally, determine the knock state by combining the abnormal amplitude of the engine body with the engine intake data: If fy × L < BY, it is determined that the knock risk within the monitoring period is high, and min{zf(z)} is set as the knock amplitude of the engine within the monitoring period; otherwise, it is determined that the knock risk within the monitoring period is normal, and max{zf(z)} is set as the knock amplitude of the engine within the monitoring period; where zf(z) represents the abnormal amplitude of the z-th engine body within the monitoring period, fy is the proportion of oxygen in the engine intake within the monitoring period, L is the volume of the engine intake, and BY is the standard oxygen volume for one complete combustion of the engine;

[0026] Furthermore, adjust the judgment process of the engine vibration state based on the knock amplitude of the engine within the monitoring period: Adjust the construction process of the engine body vibration index to γ’, and the specific process is as follows:

[0027] , b3 is the knock weight.

[0028] Optionally, set the intake air temperature threshold W to optimize the standard oxygen volume BY1 for one complete combustion of the engine when the intake air temperature is lower than the intake air temperature threshold W.

[0029] Optionally, when the vibration state of the engine body is normal and the vibration state of the environment is normal, it is determined that the actual operating state of the engine is normal;

[0030] When the vibration state of the engine body is abnormal and the vibration state of the environment is normal, no resonance model is constructed. At this time, if γ < Y × (1 + η), it is determined that the actual operating state of the engine is that the turbine blade is damaged; otherwise, it is determined that the actual operating state of the engine is that the monitoring component is damaged;

[0031] When the vibration state of the engine body is normal and the vibration state of the environment is abnormal, it is determined that the actual operating state of the engine is normal;

[0032] When the vibration state of the engine body is abnormal and the vibration state of the environment is abnormal, construct an engine resonance model, and the construction process is as follows:

[0033] μ = exp{-[(Ev - ZP) / ZP] 2-[(Ef - fE) / fE] 2}; where μ is the excitation coefficient;

[0034] Based on the excitation coefficient, level alarms are given to the user. If μ < U1, it is determined that the actual operating state of the engine is a third - level resonance risk, and a third - level resonance alarm is given to the user; if U1 ≤ μ < U2, it is determined that the actual operating state of the engine is a second - level resonance risk, and a second - level resonance alarm is given to the user; if μ ≥ U2, it is determined that the actual operating state of the engine is a first - level risk, and a first - level resonance alarm is given to the user; where U1 and U2 are the first excitation threshold and the second excitation threshold respectively.

[0035] Optionally, update the engine speed alarm system based on the actual operating state of the engine;

[0036] When the actual operating state of the engine is a first - level resonance alarm or a second - level resonance alarm, it is recommended that the user stop driving;

[0037] When the actual operating state of the engine is that the turbine blade is damaged or the monitoring component is damaged, if |γ - Y×(1 + η)| / Y < η, set the engine alarm speed to ZS1, and set ZS1 = ZS×{1 - |γ - Y×(1 + η)| / Y}; otherwise, it is recommended that the user stop driving;

[0038] When the actual operating state of the engine is a third - level resonance alarm, set the engine alarm speed to ZS2, and set ZS2 = ZS×{μ - |γ - Y×(1 + η)| / Y}.

[0039] Optionally, periodically collect the engine vibration data within the monitoring period through the sensor network, and synchronously record the engine load data and the additional vibration data;

[0040] Pre - process the additional vibration data recorded within the monitoring period;

[0041] Based on the pre - processing result of the additional vibration data, judge the external mechanical state: when Ev < EF, it is determined that the external mechanical state within the monitoring period is normal; when Ev ≥ EF, if Ef / Eσ < B, it is determined that the external mechanical state within the monitoring period is normal; otherwise, it is determined that the external mechanical state within the monitoring period is abnormal;

[0042] Where Ef is the peak of the additional mechanical vibration within the monitoring period, EF is the mechanical frequency threshold, Ev is the additional mechanical vibration frequency within the monitoring period, Eσ is the standard deviation of the additional mechanical vibration within the monitoring period, and B is the coefficient of variation threshold.

[0043] Optionally, determine whether the ambient noise state is normal based on the pre - processing result of the additional vibration data and the judgment result of the external mechanical state;

[0044] Based on the analysis results of the comprehensive external mechanical vibration state and the ambient noise state, the environmental vibration state is analyzed through fusion to determine whether the environmental vibration state is normal.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows: through multi-dimensional data fusion, dynamic threshold adjustment, and a hierarchical alarm mechanism, the high efficiency, accuracy, and environmental robustness of engine operating state monitoring are achieved, providing an innovative solution for engine health management. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0047] Figure 1 It is a schematic structural diagram of the method for monitoring the operating state of an engine based on vibration signals in this embodiment.

[0048] Figure 2 It is a schematic structural diagram of the method for analyzing the environmental vibration state in this embodiment.

[0049] Figure 3 It is a schematic structural diagram for determining the vibration state of the engine main body in this embodiment.

[0050] Figure 4 It is a schematic structural diagram of the method for determining the knock amplitude of the engine in this embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0051] In order to more clearly illustrate the present invention, the following further describes the present invention in conjunction with preferred embodiments and the drawings. Similar components in the drawings are denoted by the same reference numerals. Those skilled in the art should understand that the specific content described below is illustrative rather than restrictive, and should not limit the protection scope of the present invention.

[0052] It should be noted that although terms such as first, second, and third may be used in the embodiments of the present application for description, these descriptions should not be limited to these terms. These terms are only used to distinguish the descriptions. For example, without departing from the scope of the embodiments of the present application, the first can also be referred to as the second, and similarly, the second can also be referred to as the first.

[0053] Specifically, the method for monitoring the operating state of an engine based on vibration signals according to this embodiment is applied to the monitoring of vibration signals inside a turbocharged vehicle engine in a high-altitude area, and is specifically applied to a miniaturized vibration monitoring scheme for compact components of the vehicle engine to combine with high altitude; the interior of the vehicle engine described in this embodiment includes a turbocharger, a timing chain, or a high-pressure fuel pump.

[0054] Please refer to Figure 1 as shown, which is a schematic flowchart of the method for monitoring the operating state of an engine based on vibration signals according to this embodiment, including:

[0055] Step S101, periodically collect the engine vibration data within the monitoring period through a sensor network, and synchronously record the engine load data and additional vibration data; the engine vibration signals include bearing signals, piston signals, and engine body signals; the additional vibration data is the vibration data generated by the vehicle road bumps, specifically the overall vehicle vibration signal; periodically collect the engine vibration data, load data, and additional vibration data through the sensor network to ensure the comprehensiveness and real-time nature of the monitoring data; synchronously record the external vibration data such as road bumps to provide a data basis for subsequent distinguishing the engine body vibration from external interference.

[0056] Specifically, this embodiment does not specifically limit the value of the duration of the monitoring period. Those skilled in the art can freely set it as long as it meets the value requirements of the duration of the monitoring period. In this embodiment, the value of the duration of the monitoring period can be set to 5 seconds.

[0057] Specifically, in this embodiment, the acquisition method of the engine vibration signal is to set various MEMS vibration sensors and set the monitoring period as the sensor upload duration to collect the engine vibration signal.

[0058] Please continue to refer to Figure 1 as shown, the method for monitoring the operating state of an engine based on vibration signals further includes:

[0059] Step S102, preprocess the additional vibration data recorded within the monitoring period, and judge the external mechanical vibration state and environmental noise state in the form of threshold comparison based on the preprocessing result, and then comprehensively analyze the external mechanical vibration state and environmental noise state to fuse and analyze the environmental vibration state.

[0060] Please refer to Figure 2 as shown, which is a schematic flowchart of the environmental vibration state analysis method according to this embodiment, including:

[0061] Step S201, preprocess the additional vibration data recorded within the monitoring period.

[0062] Specifically, the process of preprocessing the additional vibration data in step S201 is as follows:

[0063] Perform a fast Fourier transform on the additional vibration data to obtain an additional vibration spectrum, and extract the additional vibration peaks, additional vibration frequencies, and additional vibration standard deviations; the additional vibration peaks include additional mechanical vibration peaks and additional noise vibration peaks; the additional vibration frequencies include additional mechanical vibration frequencies and additional noise vibration frequencies, and the additional vibration standard deviations include additional mechanical vibration standard deviations and additional noise vibration standard deviations; perform a fast Fourier transform on the additional vibration data, extract spectral features, and improve the efficiency and accuracy of data processing.

[0064] Specifically, in this embodiment, the process of extracting "additional vibration peaks and additional vibration frequencies" based on the additional vibration spectrum can be extracted through existing publicly available technologies. The additional vibration standard deviation is the standard deviation of the additional vibration peaks for each frame, which is used to reflect the volatility index of the additional vibration; it should be noted that the additional vibration frequency described in this embodiment takes the average value within the monitoring period, and the additional vibration peak takes the maximum value within the monitoring period.

[0065] Please continue to refer to Figure 2 As shown, the flow diagram of the environmental vibration state analysis method further includes:

[0066] Step S202, judge the external mechanical state based on the preprocessing result of the additional vibration data, and the judgment process is as follows:

[0067] When Ev < EF, it is determined that the external mechanical state within the monitoring period is normal; when Ev ≥ EF, if Ef / Eσ < B, it is determined that the external mechanical state within the monitoring period is normal; otherwise, it is determined that the external mechanical state within the monitoring period is abnormal;

[0068] Among them, Ef is the additional mechanical vibration peak within the monitoring period, EF is the mechanical frequency threshold, Ev is the additional mechanical vibration frequency within the monitoring period, Eσ is the additional mechanical vibration standard deviation within the monitoring period, and B is the coefficient of variation threshold; judge the external mechanical state and environmental noise state through threshold comparison (such as mechanical frequency threshold, coefficient of variation threshold), and effectively distinguish environmental interference from engine body abnormalities.

[0069] Specifically, in this embodiment, no specific limitations are placed on the values of the mechanical frequency threshold EF and the coefficient of variation threshold B. Those skilled in the art can freely set them as long as they meet the value requirements of the mechanical frequency threshold EF and the coefficient of variation threshold B. In this embodiment, the optimal value of the mechanical frequency threshold EF is 120% of the filtering frequency for collecting additional vibration data, and the optimal value of the coefficient of variation threshold B is 0.2.

[0070] Please continue to refer toFigure 2 As shown, the flowchart of the environmental vibration state analysis method further includes:

[0071] Step S203: Determine the environmental noise state based on the preprocessing result of the additional vibration data and the judgment result of the external mechanical state.

[0072] Specifically, the specific process of determining the environmental noise state in step S203 is as follows:

[0073] When the external mechanical state is normal, determine that the environmental noise state is normal;

[0074] When the external mechanical state is abnormal, if [[a1×(Zv - Ev)]] 2 + a2×(Zσ - Eσ)]] 2 + a3×(Zf - Ef)]] 2 / 3 < K, determine that the environmental noise state is abnormal; otherwise, determine that the environmental noise state is normal;

[0075] Where Zv is the additional noise vibration frequency within the monitoring period, Ev is the additional noise vibration peak within the monitoring period, Eσ is the standard deviation of the noise mechanical vibration within the monitoring period, a1 is the frequency weight, a2 is the standard deviation weight, a3 is the frequency weight, a1 + a2 + a3 = 1, and K is the environmental noise vibration index; by comprehensively considering the preprocessing result of the additional vibration data and the judgment result of the external mechanical state, dynamically evaluate whether the environmental noise is abnormal, introduce the comparison of the weighted formula with the threshold K, quantify the difference between the environmental noise and the mechanical vibration, avoid the limitation of single-index analysis, and when the external mechanical state is abnormal, further distinguish the environmental interference sources (such as wind speed noise or mechanical resonance) in combination with the correlation between the noise and the mechanical vibration, improving the scientificity of the noise state determination.

[0076] Specifically, in this embodiment, the value of the environmental noise vibration index K is not specifically limited, and those skilled in the art can freely set it as long as it meets the value requirement of the environmental noise vibration index K. The best value of the environmental noise vibration index K in this embodiment can be 0.2; it should be noted that the environmental noise state is specifically the vibration state caused by environmental factors such as wind speed, and the smaller the vibration difference between it and the external mechanical state, the stronger the vibration superposition effect.

[0077] Please continue to refer to Figure 2 As shown, the flowchart of the environmental vibration state analysis method further includes:

[0078] Step S204: Integrate the analysis results of the external mechanical vibration state and the environmental noise state to perform a fusion analysis on the environmental vibration state.

[0079] Specifically, the specific process of performing a fusion analysis on the environmental vibration state in step S204 is as follows:

[0080] If the external mechanical state is normal and the ambient noise state is normal, determine that the environmental vibration state is normal; if the external mechanical state is abnormal and the ambient noise state is normal, determine that the environmental vibration state is mechanical abnormal; if the external mechanical state is abnormal and the ambient noise state is abnormal, determine that the environmental vibration state is abnormal;

[0081] When the environmental vibration state is abnormal or mechanical abnormal, send a structural maintenance signal to the user.

[0082] In step S204, the external mechanical state and the ambient noise state are logically fused (normal, mechanical abnormal, overall abnormal) to form a multi-dimensional conclusion of the environmental vibration state. By excluding the unreasonable scenario of "normal external machinery but abnormal ambient noise" (system preset logic), the judgment process is simplified, redundant analysis is reduced, and the calculation efficiency is improved. When the environmental vibration state is abnormal, a structural maintenance signal is clearly triggered, providing targeted maintenance suggestions for the user and enhancing the practicality of the system.

[0083] It can be understood that in this embodiment, there is no situation where "the external mechanical state is normal and the ambient noise state is abnormal".

[0084] Please continue to refer to Figure 1 As shown, the engine operating state monitoring method based on vibration signals further includes:

[0085] Step S103, construct an engine main body vibration index based on the engine vibration data within the monitoring period, and construct a load threshold based on the engine load data, and then judge the engine main body vibration state based on the load threshold and the engine main body vibration index.

[0086] It can be understood that in this embodiment, the engine vibration data needs to be preprocessed, and the preprocessing process is the same as that of the additional vibration data, so it will not be elaborated in this embodiment.

[0087] Please refer to Figure 3 As shown, which is a flow schematic diagram for judging the engine main body vibration state in this embodiment, including:

[0088] Step S301, construct vibration factors of each local component of the engine based on the engine vibration data, and jointly construct an engine main body vibration index with the vibration factors of each local component.

[0089] Specifically, the specific process of constructing the vibration factors of each local component of the engine in step S301 is as follows:

[0090] Construct a bearing vibration factor α(i), and set α(i) = Qv(i) / r(i) × Qσ(i);

[0091] Among them, Qv(i) represents the vibration frequency of the i-th bearing, r(i) represents the rotational speed of the i-th bearing, and Qσ(i) represents the standard deviation of the vibration amplitude of the i-th bearing;

[0092] Construct the piston vibration factor β(j), and set β(j)=Hv(j) / n(j)×Hσ(j);

[0093] Among them, n(j) represents the frequency of the j-th piston within the monitoring period, Hv(j) represents the vibration frequency of the i-th piston, and Hσ(j) represents the standard deviation of the vibration amplitude of the j-th piston;

[0094] The specific process of constructing the engine body vibration index is as follows:

[0095] ;

[0096] Among them, b1 is the bearing weight, b2 is the piston weight, ZP is the engine body vibration frequency, I is the number of bearings, and J is the number of pistons; based on the bearing vibration factor (α(i)) and the piston vibration factor (β(j)), the vibration index is jointly constructed, combined with the weight distribution (b1, b2), to quantify the influence of the vibration of each component of the engine on the overall state, and enhance the pertinence of the analysis.

[0097] It can be understood that the engine body vibration frequency in this embodiment is obtained through the preprocessing of the engine vibration data, and the engine body vibration frequency is specifically the vibration frequency outside the engine body; at the same time, in this embodiment, b1 + b2 = 1, and b2 > b1, and their specific values are set by the user themselves, as long as the value requirements of b1 and b2 are met; the piston frequency is the frequency of the piston performing piston motion.

[0098] Please continue to refer to Figure 3 As shown, the method for judging the vibration state of the engine body further includes:

[0099] Step S302, construct a load threshold based on the load data within the monitoring period, and then judge the vibration state of the engine body based on the load threshold and the engine body vibration index.

[0100] Specifically, in step S032, a load threshold Y is constructed based on the load data within the monitoring period, and Y = R / ZR is set; where R is the engine speed and ZR is the transmission shaft speed;

[0101] The specific process of judging the vibration state of the engine body is as follows:

[0102] If Y×(1 - η) ≤ γ < Y×(1 + η), it is determined that the vibration state of the engine body within the monitoring period is normal; otherwise, it is determined that the vibration state of the engine body within the monitoring period is abnormal;

[0103] Among them, η is the offset coefficient, where 0 < η < 0.3; the vibration state is dynamically judged as abnormal through the load threshold (Y = R / ZR), and the offset coefficient (η) is combined to improve the fault tolerance and adaptability of the judgment.

[0104] Specifically, in this embodiment, no specific limitation is imposed on the value of the offset coefficient η, and it only needs to meet the value requirement of the offset coefficient η. The optimal value of the offset coefficient η in this embodiment is 0.15; it should be noted that in this embodiment, the phenomenon of γ ≥ Y×(1 + η) indicates that the vibration of the monitoring component is the main cause of the abnormal vibration state of the engine main body; γ < Y×(1 + η) indicates that the vibration of the monitoring component is not the main cause of the abnormal vibration state of the engine main body.

[0105] Please continue to refer to Figure 1 As shown, the engine operating state monitoring method based on vibration signals further includes:

[0106] Step S104, when the vibration state of the engine main body is abnormal, extract the abnormal amplitude of the engine main body, and combine the engine intake data to determine the knock amplitude of the engine within the monitoring period, and then adjust the judgment process of the vibration state of the engine main body.

[0107] Please refer to Figure 4 As shown, it is the knock amplitude determination method of the engine described in this embodiment, including:

[0108] Step S401, when the vibration state of the engine main body is abnormal, extract the abnormal amplitude of the engine main body.

[0109] Specifically, the judgment process of the abnormal amplitude of the engine main body in this embodiment is as follows:

[0110] Calculate the amplitude variation coefficient fb of the engine main body and the average amplitude fE of the engine main body, and set the abnormal amplitude threshold YF, where YF = fb×fE;

[0111] Compare the vibration amplitude of the engine main body within the monitoring period with the abnormal amplitude threshold YF, and set the vibration amplitude of the engine main body exceeding the abnormal amplitude YF as the abnormal amplitude of the engine main body; dynamically set the abnormal amplitude threshold (YF = fb×fE) through the amplitude variation coefficient (fb) and the average value (fE) to avoid the limitations of a fixed threshold and improve the sensitivity of abnormal detection.

[0112] Please refer to Figure 4 As shown, the knock amplitude determination method of the engine described above further includes:

[0113] Step S402, determine the knock amplitude of the engine within the monitoring period by combining the abnormal amplitude of the engine main body with the engine intake data, and then adjust the judgment process of the vibration state of the engine main body.

[0114] Specifically, the adjustment process of the vibration state of the engine body is as follows:

[0115] Determine the knocking state by combining the abnormal amplitude of the engine body extracted with the engine intake data: If fy×L < BY, it is determined that the knocking risk is high during the monitoring period, and min{zf(z)} is set as the knocking amplitude of the engine during the monitoring period; otherwise, it is determined that the knocking risk is normal during the monitoring period, and max{zf(z)} is set as the knocking amplitude of the engine during the monitoring period; where zf(z) represents the abnormal amplitude of the z-th engine body during the monitoring period, fy is the oxygen ratio of the engine intake during the monitoring period, L is the intake volume of the engine, and BY is the standard oxygen volume for complete combustion of the engine once.

[0116] Furthermore, based on the knocking amplitude of the engine during the monitoring period, adjust the judgment process of the engine vibration state: Adjust the construction process of the engine body vibration index to γ’, and the specific process is as follows:

[0117] , b3 is the knocking weight; combine the intake data (oxygen ratio, volume) and the knocking amplitude (min / max{zf(z)}) to determine the knocking risk, and adjust the vibration index with the knocking weight (b3) to enhance the adaptability to alpine or extreme working conditions.

[0118] Specifically, the value of the knocking weight b3 is not specifically limited in this embodiment, and those skilled in the art can freely set it as long as it meets the value requirements of the knocking weight b3. The best value of the knocking weight b3 in this embodiment is 0.5.

[0119] Please continue to refer to Figure 4 As shown, the method for determining the knocking amplitude of the engine further includes:

[0120] Step S403, further optimize the judgment process of the engine vibration state according to the intake temperature during the monitoring period.

[0121] Specifically, in step S403, an intake temperature threshold W is set. When the intake temperature is lower than the intake temperature threshold W, the standard oxygen volume for complete combustion of the engine once is optimized to BY1, and it is set that BY1 = exp{(W - w) / W}×BY; for extreme environments (high altitude, alpine regions), the standard oxygen volume is adaptively adjusted by temperature to make up for the problem that the traditional method ignores the influence of intake temperature on combustion, and improve the robustness of the monitoring system under complex working conditions. The formula design (exponential function) ensures the non-linear response of BY1 to temperature changes, which is more in line with the non-linear relationship between actual combustion efficiency and temperature.

[0122] Specifically, in this embodiment, the intake air temperature threshold W is set with the optimal intake air temperature of the engine as the optimal value.

[0123] Please continue to refer to Figure 1 As shown, the engine operating state monitoring method based on vibration signals further includes:

[0124] Step S105, comprehensively monitor the vibration state of the engine body and the environmental vibration state within the monitoring period to construct a resonance model of the engine within the monitoring period, so as to judge the actual operating state of the engine, and further determine the actual fault type of the engine.

[0125] Specifically, the specific process of determining the actual fault type of the engine in step S105 is as follows:

[0126] When the vibration state of the engine body is normal and the environmental vibration state is normal, it is judged that the actual operating state of the engine is normal;

[0127] When the vibration state of the engine body is abnormal and the environmental vibration state is normal, the resonance model is not constructed. At this time, if γ < Y×(1 + η), it is determined that the actual operating state of the engine is that the turbine blade is damaged, otherwise, it is determined that the actual operating state of the engine is that the monitoring component is damaged;

[0128] When the vibration state of the engine body is normal and the environmental vibration state is abnormal, it is determined that the actual operating state of the engine is normal;

[0129] When the vibration state of the engine body is abnormal and the environmental vibration state is abnormal, construct the engine resonance model, and its construction process is as follows:

[0130] μ = exp{-[(Ev - ZP) / ZP] 2 -[(Ef - fE) / fE] 2}; where μ is the excitation coefficient;

[0131] According to the excitation coefficient, level alarms are given to the user. If μ < U1, it is determined that the actual operating state of the engine is a third-level resonance risk, and a third-level resonance alarm is given to the user; if U1 ≤ μ < U2, it is determined that the actual operating state of the engine is a second-level resonance risk, and a second-level resonance alarm is given to the user; if μ ≥ U2, it is determined that the actual operating state of the engine is a first-level risk, and a first-level resonance alarm is given to the user; where U1 and U2 are the first excitation threshold and the second excitation threshold respectively; comprehensively considering the engine vibration state and the environmental vibration state, construct the excitation coefficient (μ) to quantify the resonance risk level, realize multi-dimensional fault diagnosis; according to the deviation degree between the environmental vibration state and the engine body vibration index, accurately distinguish the fault types (such as turbine blade damage, monitoring component damage), and reduce misjudgment.

[0132] Specifically, in this embodiment, the values of the first excitation threshold and the second excitation threshold are not specifically limited, and those skilled in the art can freely set them as long as the value requirements of the first excitation threshold and the second excitation threshold are met. In this embodiment, the optimal value of U1 is 0.6, and the optimal value of U2 is 0.8.

[0133] Please continue to refer to Figure 1 As shown, the engine operating state monitoring method based on vibration signals further includes:

[0134] Step S106, updating the engine speed alarm system based on the actual operating state of the engine.

[0135] Specifically, the specific process of updating the engine speed alarm system is as follows:

[0136] When the actual operating state of the engine is a first-level resonance alarm or a second-level resonance alarm, it is recommended that the user stop driving;

[0137] When the actual operating state of the engine is that the turbine blade is damaged or the monitoring component is damaged, if |γ - Y×(1 + η)| / Y < η, set the engine alarm speed to ZS1, and set ZS1 = ZS×{1 - |γ - Y×(1 + η)| / Y}; otherwise, it is recommended that the user stop driving;

[0138] When the actual operating state of the engine is a third-level resonance alarm, set the engine alarm speed to ZS2, and set ZS2 = ZS×{μ - |γ - Y×(1 + η)| / Y}; dynamically adjust the alarm speed (ZS1, ZS2) according to the actual operating state, and combine the resonance risk level and the degree of component damage to provide a hierarchical alarm recommendation (such as recommending to stop driving or restricting the speed) to improve the safety of user operations.

[0139] So far, the technical solution of the present invention has been described in combination with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present invention.

Claims

1. A method for monitoring engine operating status based on vibration signals, characterized in that: include: An engine main body vibration index is constructed based on the engine vibration data within a monitoring period, and a load threshold is constructed based on the engine load data, and then the engine main body vibration state is determined based on the load threshold and the engine main body vibration index; When the vibration state of the engine body is abnormal, the abnormal amplitude of the engine body is extracted, and the knock amplitude of the engine within the monitoring period is determined in combination with the engine intake data, thereby adjusting the judgment process of the vibration state of the engine body; The vibration state of the engine body and the ambient vibration state during the monitoring period are comprehensively considered to construct a resonance model of the engine during the monitoring period, so as to judge the actual operating state of the engine and further determine the actual fault type of the engine; Based on the engine vibration data, the vibration factors of each local component of the engine are constructed, and the vibration index of the engine body is jointly constructed with the vibration factors of each local component; The specific process of constructing the vibration factors of each local component of the engine is as follows: Construct the bearing vibration factor α(i), and set α(i)=Qv(i) / r(i)×Qσ(i); Among them, Qv(i) represents the vibration frequency of the i-th bearing, r(i) represents the speed of the i-th bearing, and Qσ(i) represents the standard deviation of the vibration amplitude of the i-th bearing; Construct the piston vibration factor β(j), and set β(j)=Hv(j) / n(j)×Hσ(j); Where n(j) represents the frequency of the jth piston in the monitoring period, Hv(j) represents the vibration frequency of the jth piston, and Hσ(j) represents the standard deviation of the vibration amplitude of the jth piston; The specific process of constructing the engine body vibration index is as follows: ； Among them, b1 is the bearing weight, b2 is the piston weight, ZP is the engine body vibration frequency, I is the number of bearings, and J is the number of pistons.

2. The engine operating status monitoring method based on vibration signals according to claim 1, characterized in that: The load threshold Y is constructed based on the load data in the monitoring period, and Y=R / ZR is set; where R is the engine speed and ZR is the transmission shaft speed; The specific process of judging the vibration state of the engine body is as follows: If Y×(1-η)≤γ<Y×(1+η), it is determined that the vibration state of the engine body during the monitoring period is normal; otherwise, it is determined that the vibration state of the engine body during the monitoring period is abnormal; Wherein, η is the offset coefficient, 0<η<0.

3.

3. The engine operating status monitoring method based on vibration signals according to claim 2 is characterized in that: Calculate the engine main body amplitude variation coefficient fb and the engine main body amplitude mean fE, and set the abnormal amplitude threshold YF, setting YF=fb×fE; The vibration amplitude of the engine body within the monitoring period is compared with the abnormal amplitude threshold value YF, and the vibration amplitude of the engine body exceeding the abnormal amplitude YF is set as the abnormal amplitude of the engine body.

4. The engine operating status monitoring method based on vibration signals according to claim 3 is characterized in that: The knock state is determined by combining the extracted abnormal amplitude of the engine main body with the engine intake data: if fy×L<BY, it is determined that the knock risk in the monitoring period is high, and min{zf(z)} is set as the knock amplitude of the engine in the monitoring period; otherwise, it is determined that the knock risk in the monitoring period is normal, and max{zf(z)} is set as the knock amplitude of the engine in the monitoring period; wherein zf(z) represents the abnormal amplitude of the zth engine main body in the monitoring period, fy is the engine intake oxygen ratio in the monitoring period, L is the engine intake volume, and BY is the standard oxygen volume for a full combustion of the engine; Then, the judgment process of the engine vibration state is adjusted according to the knock amplitude of the engine during the monitoring period: the construction process of the engine main body vibration index is adjusted to γ'. The specific process is as follows: , b3 is the knock weight.

5. The engine operating status monitoring method based on vibration signals according to claim 4 is characterized in that: The intake air temperature threshold W is set so that when the intake air temperature is lower than the intake air temperature threshold W, the standard oxygen volume for a complete combustion of the engine is optimized to BY1.

6. The engine operating status monitoring method based on vibration signals according to claim 5, characterized in that: When the vibration state of the engine body is normal and the ambient vibration state is normal, it is determined that the actual operating state of the engine is normal; When the vibration state of the engine body is abnormal and the ambient vibration state is normal, the resonance model is not constructed. At this time, if γ<Y×(1+η), the actual operating state of the engine is determined to be that the turbine blade is damaged. Otherwise, the actual operating state of the engine is determined to be that the monitoring component is damaged. When the vibration state of the engine body is normal and the ambient vibration state is abnormal, determining that the actual operating state of the engine is normal; When the vibration state of the engine body is abnormal and the ambient vibration state is abnormal, an engine resonance model is constructed, and the construction process is as follows: μ=exp{-[(Ev-ZP) / ZP] 2 -[(Ef-fE) / fE] 2 }; where μ is the excitation coefficient; A level alarm is given to the user based on the excitation coefficient. If μ<U1, the actual operating state of the engine is determined to be a third-level resonance risk, and a third-level resonance alarm is given to the user; if U1≤μ<U2, the actual operating state of the engine is determined to be a second-level resonance risk, and a second-level resonance alarm is given to the user; if μ≥U2, the actual operating state of the engine is determined to be a first-level risk, and a first-level resonance alarm is given to the user; wherein, U1 and U2 are the first excitation threshold and the second excitation threshold, respectively.

7. The engine operating status monitoring method based on vibration signals according to claim 6, characterized in that: Update the engine speed warning system based on the actual operating status of the engine; When the actual operating state of the engine is the first-level resonance alarm or the second-level resonance alarm, it is recommended that the user stop driving; When the actual operating state of the engine is that the turbine blade is damaged or the monitoring component is damaged, if |γ-Y×(1+η)| / Y<η, the engine alarm speed is set to ZS1, and ZS1=ZS×{1-|γ-Y×(1+η)| / Y}; otherwise, it is recommended that the user stop driving; When the actual operating state of the engine is the third-level resonance alarm, the engine alarm speed is set to ZS2, and ZS2=ZS×{μ-|γ-Y×(1+η)| / Y} is set.

8. The engine operating status monitoring method based on vibration signals according to claim 7, characterized in that: The sensor network periodically collects engine vibration data during the monitoring period, and simultaneously records engine load data and additional vibration data; Pre-processing of additional vibration data recorded during the monitoring period; The external mechanical state is judged based on the preprocessing result of the additional vibration data: when Ev<EF, the external mechanical state within the monitoring period is judged to be normal; when Ev≥EF, if Ef / Eσ<B, the external mechanical state within the monitoring period is judged to be normal; otherwise, the external mechanical state within the monitoring period is judged to be abnormal; Among them, Ef is the additional mechanical vibration peak during the monitoring period, EF is the mechanical frequency threshold, Ev is the additional mechanical vibration frequency during the monitoring period, Eσ is the additional mechanical vibration standard deviation during the monitoring period, and B is the coefficient of variation threshold.

9. The engine operating status monitoring method based on vibration signals according to claim 8, characterized in that: Determining whether the environmental noise state is normal based on the preprocessing result of the additional vibration data and the judgment result of the external mechanical state; The analysis results of the external mechanical vibration state and the environmental noise state are integrated to perform a fusion analysis of the environmental vibration state to determine whether the environmental vibration state is normal.

Images