Engine running state monitoring method based on vibration signals

Abstract

The invention relates to the technical field of engine state monitoring, in particular to an engine running state monitoring method based on vibration signals, which comprises the following steps: acquiring engine vibration data in a monitoring period, and synchronously recording engine load data and additional vibration data; the method comprises the following steps: pre-processing extra vibration data, analyzing an environment vibration state, constructing an engine main body vibration index according to engine vibration data, constructing a load threshold value, 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. A resonance model of the engine in the monitoring period is constructed to judge the actual operation state of the engine, and then the actual fault type of the engine is determined; and updating the engine speed alarm system based on the actual operation state of the engine. The engine running state monitoring efficiency based on the vibration signals is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of engine status monitoring, and in particular to a method for monitoring engine operating status based on vibration signals. Background Art

[0002] In recent years, with the development of sensor technology and data analysis methods, the use of vibration signals for mechanical fault diagnosis has become an effective way. However, the existing technology still has certain limitations in vibration signal processing, feature extraction and fault pattern recognition, which limits its application effect.

[0003] Chinese patent publication number CN118565836A discloses a vehicle 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 conditions, an operation monitoring module for analyzing engine vibration conditions, and analyzing vibration change conditions within a monitoring period, and also analyzing abnormal vibration conditions, an adjustment and optimization module for adjusting the analysis process of engine vibration conditions, and optimizing the adjustment process of engine vibration conditions based on the results, a combustion monitoring module for analyzing abnormal combustion conditions, and an abnormal alarm module for analyzing engine operation conditions; it can be seen that when the invention monitors the engine, the engine operation conditions are monitored by comprehensively considering the environment and vibration, and the vibration signals of each engine component and the resonance effect between the engine and the external vibration are not specifically analyzed, and there is a problem of low efficiency in vibration signal analysis; at the same time, it lacks an analysis process for engine knock signals in high-cold areas, and there is an inaccurate problem in monitoring the engine operation conditions. Summary of the invention

[0004] An object of the present invention is to provide a method for monitoring engine operating status based on vibration signals to solve at least one of the problems existing in the prior art.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A method for monitoring engine operating status based on vibration signals, comprising: 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 monitored to construct a resonance model of the engine during the monitoring period to determine the actual operating state of the engine and further determine the actual fault type of the engine.

[0006] Optionally, a vibration factor of each local component of the engine is constructed based on the engine vibration data, and the vibration factor of each local component is used to jointly construct the engine main body vibration index; 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.

[0007] Optionally, a load threshold value Y is constructed based on the load data in the monitoring period, and Y=R / ZR is set; wherein 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.

[0008] Optionally, the engine main body amplitude variation coefficient fb and the engine main body amplitude mean fE are calculated, and an abnormal amplitude threshold YF is set, and YF=fb×fE is set; 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.

[0009] Optionally, 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 to 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 to 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 of 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.

[0010] Optionally, an intake temperature threshold W is set so that when the intake temperature is lower than the intake temperature threshold W, the standard oxygen volume for a complete combustion of the engine is optimized to BY1.

[0011] Optionally, 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.

[0012] Optionally, updating an engine speed warning system based on the actual operating state 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.

[0013] Optionally, engine vibration data within a monitoring period is periodically collected through a sensor network, and engine load data and additional vibration data are simultaneously recorded; 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.

[0014] Optionally, determining whether the ambient 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.

[0015] Compared with the prior art, the beneficial effects of the present invention are: through multi-dimensional data fusion, dynamic threshold adjustment and hierarchical alarm mechanism, the efficiency, accuracy and environmental robustness of engine operating status monitoring are achieved, providing an innovative solution for engine health management. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1Schematic diagram of the structure of the engine operating status monitoring method based on vibration signals in this embodiment.

[0018] Figure 2 Schematic diagram of the structure of the environmental vibration state analysis method of this embodiment.

[0019] Figure 3 It is a schematic diagram of the structure for judging the vibration state of the engine body in this embodiment.

[0020] Figure 4 It is a structural schematic diagram of the method for determining the knock amplitude of the engine of this embodiment. DETAILED DESCRIPTION

[0021] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same reference numerals. It should be understood by those skilled in the art that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0022] It should be noted that, although the terms first, second, third, etc. may be used to describe in the embodiments of the present application, 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 may also be referred to as the second, and similarly, the second may also be referred to as the first.

[0023] Specifically, the engine operating status monitoring method based on vibration signals described in this embodiment is applied to vibration signal monitoring inside a turbocharged automobile engine in high-altitude areas, and is specifically applied to a miniaturized vibration monitoring scheme for compact components of automobile engines to combine with high altitudes; the automobile engine described in this embodiment includes a turbocharger, a timing chain or a high-pressure fuel pump.

[0024] See also Figure 1 As shown, it is a flow chart of the engine operation status monitoring method based on vibration signals according to this embodiment, including: Step S101, periodically collect engine vibration data within a monitoring period through a sensor network, and synchronously record engine load data and additional vibration data; the engine vibration signal includes a bearing signal, a piston signal, and an engine body signal; the additional vibration data is vibration data generated by vehicle road bumps, specifically, the overall vehicle vibration signal; periodically collect engine vibration data, load data, and additional vibration data through a sensor network to ensure the comprehensiveness and real-time nature of the monitoring data; synchronously record external vibration data such as road bumps to provide a data basis for subsequently distinguishing between engine body vibration and external interference.

[0025] Specifically, this embodiment does not impose any specific limitation on the value of the duration of the monitoring period, and those skilled in the art can freely set it as long as the value requirement of the duration of the monitoring period is met. In this embodiment, the value of the duration of the monitoring period can be set to 5 seconds.

[0026] Specifically, the engine vibration signal collection method described in this embodiment is to set various MEMS vibration sensors and set the monitoring period to the sensor upload time to collect the engine vibration signal.

[0027] Please continue reading Figure 1 As shown, the engine operating status monitoring method based on the vibration signal also includes: Step S102, preprocessing the additional vibration data recorded during the monitoring period, and judging the external mechanical vibration state and the environmental noise state by threshold comparison based on the preprocessing result, and then integrating the external mechanical vibration state and the environmental noise state to integrate and analyze the environmental vibration state.

[0028] See also Figure 2 As shown, it is a flow chart of the environmental vibration state analysis method described in this embodiment, including: Step S201 , pre-processing the additional vibration data recorded during the monitoring period.

[0029] Specifically, the process of preprocessing the additional vibration data in step S201 is as follows: Perform fast Fourier transform on the additional vibration data to obtain additional vibration spectrum, and extract additional vibration peak, additional vibration frequency and additional vibration standard deviation; the additional vibration peak includes additional mechanical vibration peak and additional noise vibration peak; the additional vibration frequency includes additional mechanical vibration frequency and additional noise vibration frequency, and the additional vibration standard deviation includes additional mechanical vibration standard deviation and additional noise vibration standard deviation; perform fast Fourier transform on the additional vibration data, extract spectrum features, and improve data processing efficiency and accuracy.

[0030] 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 public technologies. The additional vibration standard deviation is the standard deviation of the additional vibration peaks of each frame, which is used to reflect the volatility index of the additional vibration. It is worth noting that the additional vibration frequency described in this embodiment is the average value within the monitoring period, and the additional vibration peak is the maximum value within the monitoring period.

[0031] Please continue reading Figure 2 As shown, the flow chart of the environmental vibration state analysis method also includes: Step S202, judging the external mechanical state based on the preprocessing result of the additional vibration data, the judging process is as follows: 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 standard deviation of the additional mechanical vibration during the monitoring period, and B is the coefficient of variation threshold. The external mechanical state and environmental noise state are judged by threshold comparison (such as mechanical frequency threshold, coefficient of variation threshold) to effectively distinguish environmental interference from engine abnormalities.

[0032] Specifically, in this embodiment, there is no specific limitation on the values ​​of the mechanical frequency threshold EF and the coefficient of variation threshold B. Those skilled in the art can set them freely as long as the value requirements of the mechanical frequency threshold EF and the coefficient of variation threshold B are met. In this embodiment, the optimal value of the mechanical frequency threshold EF is 120% of the filtering frequency of the additional vibration data collection, and the optimal value of the coefficient of variation threshold B is 0.2.

[0033] Please continue reading Figure 2 As shown, the flow chart of the environmental vibration state analysis method also includes: Step S203: determining the environmental noise state based on the preprocessing result of the additional vibration data and the judgment result of the external mechanical state.

[0034] Specifically, the specific process of determining the ambient noise state in step S203 is as follows: When the external mechanical state is normal, the environmental noise state is determined to be normal; When the external mechanical state is abnormal, if [a1×(Zv-Ev) 2 +a2×(Zσ-Eσ) 2 +a3×(Zf-Ef) 2 ] / 3<K, the environmental noise state is determined to be abnormal; otherwise, the environmental noise state is determined to be normal; Among them, Zv is the additional noise vibration frequency during the monitoring period, Ev is the additional noise vibration peak during the monitoring period, Ev is the noise mechanical vibration standard deviation during 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 combining the preprocessing results of the additional vibration data and the judgment results of the external mechanical state, it is dynamically evaluated whether the environmental noise is abnormal, and the weighted formula is introduced to compare with the threshold K to quantify the difference between environmental noise and mechanical vibration, avoiding the limitations of single indicator analysis. When the external mechanical state is abnormal, the correlation between noise and mechanical vibration is combined to further distinguish environmental interference sources (such as wind speed noise or mechanical resonance) to improve the scientific nature of noise state judgment.

[0035] Specifically, in this embodiment, the value of the environmental noise vibration index K is not specifically limited, and technical personnel in this field can set it freely as long as the value requirement of the environmental noise vibration index K is met. In this embodiment, the optimal value of the environmental noise vibration index K can be 0.2; it is worth noting that the environmental noise state is specifically the vibration state caused by environmental factors such as wind speed. The smaller the vibration difference between the environmental noise state and the external mechanical state, the stronger the vibration superposition effect.

[0036] Please continue reading Figure 2 As shown, the flow chart of the environmental vibration state analysis method also includes: Step S204, combining the analysis results of the external mechanical vibration state and the environmental noise state to perform a fusion analysis on the environmental vibration state.

[0037] Specifically, the specific process of the step S204 for fusion analysis of the environmental vibration state is as follows: If the external mechanical state is normal and the environmental noise state is normal, the environmental vibration state is determined to be normal; if the external mechanical state is abnormal and the environmental noise state is normal, the environmental vibration state is determined to be mechanical abnormality; if the external mechanical state is abnormal and the environmental noise state is abnormal, the environmental vibration state is determined to be abnormal; When the environmental vibration state is abnormal and the machinery is abnormal, a structural maintenance signal is sent to the user.

[0038] In step S204, the external mechanical state and the environmental noise state are logically integrated (normal, mechanical abnormality, overall abnormality) to form a multi-dimensional conclusion of the environmental vibration state. By excluding the unreasonable scenario of "external machinery is normal but environmental noise is abnormal" (system preset logic), the judgment process is simplified, redundant analysis is reduced, and computing efficiency is improved. When the environmental vibration state is abnormal, the structural maintenance signal is clearly triggered to provide users with targeted maintenance suggestions, thereby enhancing the practicality of the system.

[0039] It can be understood that in this embodiment, the situation of "the external mechanical state is normal and the environmental noise state is abnormal" does not occur.

[0040] Please continue reading Figure 1 As shown, the engine operating status monitoring method based on the vibration signal also includes: Step S103, constructing an engine main body vibration index according to the engine vibration data within the monitoring period, and constructing a load threshold according to the engine load data, and then judging the engine main body vibration state based on the load threshold and the engine main body vibration index.

[0041] It is understandable that the present embodiment requires preprocessing of the engine vibration data, and the preprocessing process is the same as the preprocessing process of the additional vibration data, which will not be described in detail in the present embodiment.

[0042] See also Figure 3 As shown, it is a schematic diagram of the flow chart of judging the vibration state of the engine body according to this embodiment, including: Step S301: constructing vibration factors of local components of the engine based on engine vibration data, and jointly constructing the engine main body vibration index with the vibration factors of the local components.

[0043] Specifically, the specific process of constructing the vibration factors of each local component of the engine in step S301 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 i-th piston, and Hσ(j) represents the standard deviation of the vibration amplitude of the j-th piston; The specific process of constructing the engine body vibration index is as follows: ; Where b1 is the bearing weight, b2 is the piston weight, ZP is the vibration frequency of the engine body, I is the number of bearings, and J is the number of pistons. The vibration index is jointly constructed based on the bearing vibration factor (α(i)) and the piston vibration factor (β(j)). Combined with the weight distribution (b1, b2), the influence of the vibration of each engine component on the overall state is quantified to enhance the targeted analysis.

[0044] It can be understood that the engine body vibration frequency described in this embodiment is obtained by preprocessing the engine vibration data, and the engine body vibration frequency is specifically the vibration frequency of the outside of the engine body; at the same time, in this embodiment, b1+b2=1, and b2>b1, and its specific value is set by the user, and it only needs to meet the b1 and b2 value requirements; the piston frequency is the frequency of the piston's piston movement.

[0045] Please continue reading Figure 3 As shown, the method for determining the vibration state of the engine body also includes: Step S302: construct a load threshold based on the load data in the monitoring period, and then determine the vibration state of the engine body based on the load threshold and the engine body vibration index.

[0046] Specifically, the step S032 constructs a load threshold value Y based on the load data in the monitoring period, and sets Y=R / ZR; wherein 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; Among them, η is the offset coefficient, 0<η<0.3; the load threshold (Y=R / ZR) is used to dynamically judge whether the vibration state is abnormal, and the offset coefficient (η) is combined to improve the fault tolerance and adaptability of the judgment.

[0047] Specifically, this embodiment does not make any specific limitation on the value of the offset coefficient η, and 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 is worth noting 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 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 body.

[0048] Please continue reading Figure 1 As shown, the engine operating status monitoring method based on the vibration signal also includes: Step S104, 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.

[0049] See also Figure 4 As shown, the method for determining the knock amplitude of the engine described in this embodiment includes: Step S401, when the vibration state of the engine body is abnormal, extract the abnormal amplitude of the engine body.

[0050] Specifically, the process of determining the abnormal amplitude of the engine main body in this embodiment is as follows: 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 abnormal amplitude threshold YF is used to compare the vibration amplitude of the engine body during the monitoring period, and the vibration amplitude of the engine body that exceeds the abnormal amplitude YF is set as the abnormal amplitude of the engine body. The abnormal amplitude threshold (YF=fb×fE) is dynamically set through the amplitude variation coefficient (fb) and the mean (fE) to avoid the limitations of the fixed threshold and improve the sensitivity of abnormal detection.

[0051] See also Figure 4 As shown, the method for determining the knock amplitude of the engine also includes: Step S402, determining the knock amplitude of the engine within the monitoring period based on the abnormal amplitude of the engine body in combination with the engine intake data, and then adjusting the judgment process of the vibration state of the engine body.

[0052] Specifically, the adjustment process of the vibration state of the engine body is as follows: 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; the knock risk is determined by combining the intake data (oxygen ratio, volume) and the knock amplitude (min / max{zf(z)}), and the vibration index is adjusted with the knock weight (b3) to enhance the adaptability to high cold or extreme working conditions.

[0053] Specifically, the value of the knock weight b3 is not specifically limited in this embodiment, and those skilled in the art can freely set it as long as the value requirement of the knock weight b3 is met. In this embodiment, the optimal value of the knock weight b3 is 0.5.

[0054] Please continue reading Figure 4 As shown, the method for determining the knock amplitude of the engine also includes: Step S403, further optimizing the judgment process of the engine vibration state according to the intake air temperature within the monitoring period.

[0055] Specifically, the step S403 sets the intake temperature threshold W, so that when the intake temperature is lower than the intake temperature threshold W, the standard oxygen volume for full combustion of the engine is optimized to BY1, and BY1=exp{(Ww) / W}×BY is set; for extreme environments (high altitudes, cold regions), the standard oxygen volume is adjusted adaptively by temperature to compensate for the problem that the traditional method ignores the effect of the intake temperature on combustion, and the robustness of the monitoring system under complex working conditions is improved. The formula design (exponential function) ensures the nonlinear response of BY1 to temperature changes, which is more in line with the nonlinear relationship between actual combustion efficiency and temperature.

[0056] Specifically, in this embodiment, the value of the intake air temperature threshold W is set to the optimal intake air temperature of the engine as the optimal value.

[0057] Please continue reading Figure 1 As shown, the engine operating status monitoring method based on the vibration signal also includes: Step S105, comprehensively monitoring the vibration state of the engine body and the ambient vibration state during the monitoring period to construct a resonance model of the engine during the monitoring period to determine the actual operating state of the engine and further determine the actual fault type of the engine.

[0058] Specifically, the specific process of determining the actual engine fault type in step S105 is as follows: 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; The user is given a graded alarm 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 issued 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 issued 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 issued to the user; among them, U1 and U2 are the first excitation threshold and the second excitation threshold, respectively; the engine vibration state and the environmental vibration state are combined to construct an excitation coefficient (μ) to quantify the resonance risk level and realize multi-dimensional fault diagnosis; according to the degree of deviation between the environmental vibration state and the engine main vibration index, the fault type (such as damaged turbine blades, damaged monitoring components) is accurately distinguished to reduce misjudgment.

[0059] 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 set them freely 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.

[0060] Please continue reading Figure 1 As shown, the engine operating status monitoring method based on the vibration signal also includes: Step S106: updating the engine speed alarm system based on the actual operating status of the engine.

[0061] Specifically, the process of updating the engine speed alarm system is as follows: 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; the alarm speed (ZS1, ZS2) is dynamically adjusted according to the actual operating state, and graded alarm suggestions (such as suggesting to stop driving or limit the speed) are provided in combination with the resonance risk level and the degree of component damage to improve user operation safety.

[0062] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. 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 monitored to construct a resonance model of the engine during the monitoring period to determine the actual operating state of the engine and further determine the actual fault type of the engine.

2. The engine operating status monitoring method based on vibration signals according to claim 1, characterized in that: 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.

3. The engine operating status monitoring method based on vibration signals according to claim 2 is 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.

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4. The engine operating status monitoring method based on vibration signals according to claim 3 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.

5. The engine operating status monitoring method based on vibration signals according to claim 4 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.

6. The engine operating status monitoring method based on vibration signals according to claim 5, 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.

7. The engine operating status monitoring method based on vibration signals according to claim 6, 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.

8. The engine operating status monitoring method based on vibration signals according to claim 7, 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.

9. The engine operating status monitoring method based on vibration signals according to claim 8, 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.

10. The engine operating status monitoring method based on vibration signals according to claim 9, 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.

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