Knock abnormal sound source identification method and system, electronic equipment and storage medium

Abstract

The invention provides a knocking abnormal sound source identification method and system, electronic equipment and a storage medium, and relates to the technical field of vehicle NVH, all components of a power assembly are assembled together according to the requirements of a whole vehicle, an NVH test bed is utilized to simulate the operation condition of the power assembly in the vehicle, time domain signals of different NVH data acquisition points are acquired, and the time domain signals are acquired; according to the method, time-domain signals are obtained, time-domain signal segments with abnormal knocking sound are extracted from the time-domain signals, each time-domain signal segment shows the abnormal knocking sound of a certain component of the power assembly in the running process of the power assembly, and the abnormal knocking sound source determined according to the time-domain signal segments is more suitable for the abnormal knocking sound source of the power assembly under the real vehicle running working condition. Compared with knocking abnormal sound recognition of a single engine or a transmission, the knocking problem of the assembly level can be found in advance.

Description

Technical Field

[0001] The present application relates to the field of vehicle NVH technology, and in particular to a method, system, electronic device and storage medium for identifying a knocking noise source. Background Art

[0002] The knocking problem of the powertrain of a traditional fuel engine plus a gearbox is often caused by the engine itself or the gearbox knocking caused by the engine torsional vibration. Therefore, the current mainstream technology is to identify and evaluate the knocking of the engine unit or the gearbox unit separately. However, the absence of knocking in a single engine or gearbox cannot ensure that the combined assembly of the two is knock-free. Moreover, compared with the traditional fuel powertrain, the hybrid powertrain introduces an electric motor power source, and the integrated system is more numerous and complex. Once knocking occurs, it is difficult to determine the source of the abnormal noise. This requires a powertrain-level knocking identification method to deal with the above problems. Summary of the invention

[0003] Based on this, it is necessary to provide a method, system, electronic device and storage medium for identifying the source of knocking noise in response to the above-mentioned technical problems, so as to solve the problem of identifying knocking noise at the powertrain level.

[0004] A method for identifying the source of abnormal knocking noise, the method comprising: using an NVH test bench in a knocking noise source identification system to control a powertrain to run a simulated working condition, and obtaining a time domain signal at an NVH data acquisition point during the operation of the powertrain; extracting a time domain signal segment with abnormal knocking noise from a plurality of the time domain signals; and determining the source of the abnormal knocking noise in the powertrain based on the time domain signal segment.

[0005] In an embodiment of the present application, extracting a time domain signal segment with abnormal knocking sound from a plurality of the time domain signals includes: performing time-frequency analysis on the time domain signals to obtain a time-frequency energy spectrum; determining a characteristic frequency segment where a peak in the time-frequency energy spectrum is located; and extracting a signal segment corresponding to the characteristic frequency segment from the time domain signal as the time domain signal segment with abnormal knocking sound.

[0006] In an embodiment of the present application, before performing time-frequency analysis on the time domain signal and obtaining the time-frequency energy spectrum, it also includes: converting the time domain signal into a first audio so that the test personnel can make a subjective evaluation on whether there is an abnormal knocking sound in the first audio; if the subjective evaluation result corresponding to the time domain signal is that there is an abnormal knocking sound, then executing the step of performing time-frequency analysis on the time domain signal and obtaining the time-frequency energy spectrum.

[0007] In an embodiment of the present application, the step of extracting the signal segment corresponding to the characteristic frequency segment from the time domain signal as the time domain signal segment with the abnormal knocking sound comprises: for each of the time domain signals with the abnormal knocking sound, extracting the signal segment corresponding to each of the characteristic frequency segments from the time domain signal; converting the signal segment corresponding to each of the characteristic frequency segments into a second audio, so that the experimenter can determine the target audio that can exhibit the target abnormal sound feature from all the second audios, wherein the target abnormal sound feature is the overall abnormal sound feature determined by the experimenter for the time domain signal; and using the signal segment corresponding to the target audio as the time domain signal segment with the abnormal knocking sound.

[0008] In an embodiment of the present application, determining the source of the abnormal knocking noise in the powertrain based on the time domain signal segment includes: calculating the energy value of the time domain signal segment; taking the NVH data collection point corresponding to the time domain signal segment with the largest energy value as the target position point; and determining the source of the abnormal knocking noise in the powertrain based on the target position point.

[0009] In an embodiment of the present application, determining the source of the abnormal knocking noise in the powertrain based on the time domain signal segment includes: performing a correlation analysis on signal fluctuations between the time domain signal segment and at least one of the cylinder pressure signal, the engine speed signal, and the acceleration signal of the engine speed of the powertrain; screening out a time domain signal segment with the greatest correlation in signal fluctuations from a plurality of the time domain signal segments; using the NVH data collection point corresponding to the time domain signal segment with the greatest correlation in signal fluctuations as a target position point; and determining the source of the abnormal knocking noise in the powertrain based on the target position point.

[0010] In an embodiment of the present application, the time domain signal includes a vibration signal and a noise signal; there is a preset spatial distance between the NVH data acquisition point corresponding to the noise signal and the powertrain, and the NVH data acquisition point corresponding to the vibration signal is set at different positions of the powertrain; the NVH data acquisition point corresponding to the vibration signal is set on the powertrain; the method of determining the source of the knocking noise in the powertrain based on the time domain signal segment includes: calculating the energy value of the time domain signal segment of the noise signal; determining the NVH data acquisition point corresponding to the noise signal with the largest energy value to determine the target position of the knocking noise source; screening out a target vibration signal from a plurality of vibration signals according to the target position; performing a correlation analysis of signal fluctuations on the time domain signal segment of the target vibration signal and at least one of the cylinder pressure signal, engine speed signal, and acceleration signal of the engine speed of the powertrain; screening out the time domain signal segment with the largest correlation of signal fluctuations from the time domain signal segments of the plurality of target vibration signals; and using the NVH data acquisition point corresponding to the time domain signal segment with the largest correlation of signal fluctuations as the position point of the knocking noise source.

[0011] A knocking noise source identification system, the system comprising: an NVH test bench and a powertrain of a vehicle; the NVH test bench comprises a test bench, a peripheral function module, a vibration sensor, a microphone, and a calibration control module; the powertrain is installed on the test bench; the peripheral function module is connected to a corresponding port on the powertrain, and is used to provide peripheral functions for the powertrain, so that the powertrain can operate; the vibration sensor is arranged on the powertrain; the microphone is arranged at different positions of the powertrain, and there is a preset spatial distance between the microphone and the powertrain; the data acquisition and analysis equipment is connected to the vibration sensor and the microphone, and is used to collect vibration signals and noise signals; the calibration control module is connected to a control unit of the powertrain, and is used to control the powertrain to operate in a simulated working condition.

[0012] In an embodiment of the present application, the system also includes a pressure sensor and / or a speed collection wire; the pressure sensor is arranged in the engine cylinder of the powertrain; the data collection and analysis equipment is connected to the pressure sensor for collecting the cylinder pressure signal of the powertrain; and / or; one end of the speed collection wire is connected to the signal line of the engine speed sensor in the powertrain; the other end of the speed collection wire is connected to the data collection and analysis equipment for collecting the engine speed signal and the acceleration signal of the engine speed of the powertrain.

[0013] An electronic device comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for identifying the source of abnormal knocking sound as described in any of the above embodiments are implemented.

[0014] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the method for identifying the source of abnormal knocking sound as described in the above embodiment.

[0015] In summary, the knocking noise source identification method, system, electronic device and storage medium proposed in this application assemble the powertrain components together according to the requirements of the whole vehicle, use the NVH test bench to simulate the operating conditions of the powertrain in the vehicle, and when the powertrain is running outside the vehicle in simulated conditions, collect time domain signals from different NVH data collection points, extract time domain signal segments with knocking noises from these time domain signals, and each time domain signal segment shows the knocking noise of a certain component of the powertrain during the operation of the powertrain. The knocking noise source determined based on these time domain signal segments is more in line with the knocking noise source of the powertrain under the actual vehicle operating conditions. Compared with the knocking noise identification of a single engine or transmission, it can detect assembly-level knocking problems in advance. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0017] Figure 1 is a structural schematic diagram of a knocking abnormal sound recognition system according to an exemplary embodiment of the present application; Figure 2 is a flow chart of a method for identifying abnormal knocking sound according to another exemplary embodiment of the present application; Figure 3 is a flow chart of a method for identifying abnormal knocking sound according to another exemplary embodiment of the present application; Figure 4 is a flow chart of a method for identifying abnormal knocking sound according to another exemplary embodiment of the present application; Figure 5 is a flow chart of a method for identifying abnormal knocking sound according to another exemplary embodiment of the present application; Figure 6 is a flow chart of a method for identifying abnormal knocking sound according to another exemplary embodiment of the present application; Figure 7 It is a schematic block diagram of an electronic device according to an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. The embodiments described by reference to the drawings are exemplary and are intended to be used to explain the present application, and cannot be understood as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0019] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, but does not exclude the presence or addition of one or more other features, integers, steps, operations and / or groups thereof.

[0020] It should also be understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0021] As used in the present specification and the appended claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]", depending on the context.

[0022] In addition, in the description of the present specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0023] References to "one embodiment" or "some embodiments" etc. described in the present specification mean that one or more embodiments of the present invention include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the phrases "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. appearing in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0024] This application proposes a knocking noise source identification method that can be applied to the knocking noise source identification system proposed in this application, and can identify the knocking noise of the powertrain without the whole vehicle environment. It can help engineers to timely discover and lock the knocking noise source in the early stage of powertrain product development, and avoid knocking problems after the product is installed on the vehicle.

[0025] The knock source identification system may include the NVH test bench and the vehicle's powertrain; The NVH test bench includes a test bench, peripheral function modules, vibration sensors, microphones, and calibration control modules; The powertrain is installed on the test bench; The peripheral function module is connected to the corresponding port on the powertrain and is used to provide peripheral functions for the powertrain so that the powertrain can operate; The vibration sensor is arranged on the powertrain; The microphones are arranged at different positions of the powertrain, and there is a preset spatial distance between the microphones and the powertrain; The data acquisition and analysis equipment is connected to the vibration sensor and the microphone to collect vibration signals and noise signals; The calibration control module is connected to the control unit of the powertrain and is used to control the powertrain to run in simulated working conditions.

[0026] In some embodiments, the test bench is placed in an acoustic test chamber, such as a semi-anechoic chamber.

[0027] In some embodiments, the above peripheral function modules include an intake module, an exhaust module, a fuel supply module, a temperature control module, and a battery simulation module; the intake module and the exhaust module are placed in an acoustic test room; the intake module is connected to the intake end of the engine in the hybrid powertrain to be tested through a first soundproof pipeline; the exhaust module is connected to the exhaust end of the engine in the hybrid powertrain to be tested through a second soundproof pipeline, so as to prevent the intake and exhaust noise from affecting the recognition of abnormal knocking noise.

[0028] The fuel supply module, temperature control module, and battery simulation module are all placed outside the acoustic test room; The fuel supply module is connected to the fuel delivery port on the hybrid powertrain to be tested through a fuel delivery pipeline; The temperature control module is connected to the coolant port on the hybrid powertrain to be tested through a cooling line; The battery simulation module is connected to the power port on the hybrid powertrain to be tested through a high-voltage wiring harness.

[0029] In some embodiments, the knocking noise source identification system also includes a pressure sensor and / or a speed collection wire; the pressure sensor is arranged in the engine cylinder of the powertrain; the data collection and analysis equipment is connected to the pressure sensor for collecting the cylinder pressure signal of the powertrain; and / or; one end of the speed collection wire is connected to the signal line of the engine speed sensor on the powertrain; the other end of the speed collection wire is connected to the data collection and analysis equipment for collecting the engine speed signal and the acceleration signal of the engine speed of the powertrain.

[0030] It should be noted that the data acquisition and analysis equipment in the implementation of this application may be a device or system that can collect, process and analyze data from various sources; all sensors involved in this application can be connected to the above-mentioned data acquisition and analysis equipment, and the data acquisition and analysis equipment will obtain the electrical signal of the sensor, and convert the electrical signal into a digital signal for analysis and processing.

[0031] For example, Figure 1 , which is a schematic diagram of a knocking noise source identification system, and uses an NVH test bench to identify the knocking noise source of a hybrid powertrain. Figure 1It includes a hybrid powertrain 1, a test bench 2 in the NVH test bench, a semi-anechoic chamber 3 where the test bench is located, a fuel supply module 4, a temperature control module 5, an intake module 6, an exhaust module 7, a battery simulation module 8, a vibration and noise test module 9, and a calibration control module 10.

[0032] The hybrid powertrain 1 is assembled according to the conditions of the whole vehicle and is suspended on a test bench 2 (the test bench can be understood as a test bench body of the NVH test bench) in the NVH test bench through suspension elements. The test bench 2 is located in a semi-anechoic chamber 3.

[0033] The test bench motor is placed outside the semi-anechoic chamber 3, and the motor wire is connected to the hybrid powertrain 1 through a through-wall shaft.

[0034] The hybrid powertrain 1 is cooled without using a vehicle cooler, but the cooling pipeline is connected to the temperature control module 5 of the NVH test bench.

[0035] The power high-voltage wiring harness of the hybrid powertrain 1 is connected to the battery simulation module 8; The air inlet of the engine is connected to the air inlet module 6 of the test bench 2 through a soundproof pipeline, and the air outlet of the engine is connected to the exhaust module 7 through a soundproof pipeline.

[0036] Figure 1 The vibration and noise test module 9 may include a vibration sensor, a microphone, a cylinder pressure sensor, a speed sensor and a data acquisition and analysis device; a plurality of vibration sensors are respectively installed on the active side of the suspension element of the hybrid powertrain 1, the passive side of the suspension element, the engine cylinder block, the hybrid transmission housing and other positions; microphones are set in all directions of the hybrid powertrain 1, cylinder pressure sensors are arranged in each cylinder of the engine, the engine speed sensor signal is led out through a wire breaking needle, a hole is opened on the housing at the gear position of the hybrid transmission to install a speed sensor for measuring the gear speed, all of the above sensors are connected to the data acquisition and analysis device through a wiring harness, and the calibration control module 10 is connected to the control unit of the hybrid powertrain 1 through a wiring harness to control the power output of the hybrid powertrain 1.

[0037] The present invention assembles the powertrain components together according to the requirements of the vehicle, uses a test bench, peripheral function modules and calibration control modules to simulate the operating state of the powertrain in the vehicle, uses a vibration and noise test module to obtain the vibration and noise of the hybrid powertrain during operation, and determines the source of the abnormal knocking noise by analyzing the vibration and noise. Compared with the identification of the abnormal knocking noise of a single engine or gearbox, the present invention can detect the knocking problem at the assembly level in advance, and also eliminates the influence of other components of the vehicle except the powertrain, which is conducive to determining the real source of the abnormal knocking noise.

[0038] Figure 2This is a flow chart of a method for identifying the source of abnormal knocking sound proposed in an embodiment of the present application, such as Figure 2 As shown, the method includes: S201, using the NVH test bench in the knocking noise source identification system, controlling the powertrain to run a simulated working condition, and obtaining the time domain signal at the NVH data collection point during the operation of the powertrain.

[0039] The calibration control module in the NVH test bench sends control signals to the powertrain control unit to control the powertrain to run in simulated conditions.

[0040] For example, the simulated operating condition may be any one of a variety of operating conditions such as start-stop, idling, fixed gear acceleration / deceleration or cruising operating conditions of the powertrain running on the whole vehicle.

[0041] In some embodiments, the sources of abnormal knocking noises that may occur in the powertrain under different operating conditions can be identified by switching simulated operating conditions.

[0042] Furthermore, the temperature, power level and other external conditions during the operation of the powertrain can be adjusted as needed to detect abnormal knocking noises of the powertrain under various conditions, thereby increasing the coverage of the identification of the source of the abnormal knocking noises.

[0043] For example, the temperature control module of the NVH test bench can be used to adjust the operating temperature of each component of the powertrain according to demand. The battery simulation module of the NVH test bench can be used to adjust the power supply of the powertrain according to demand.

[0044] In the embodiment of the present application, when the powertrain is running under simulated working conditions, the time domain signals at the NVH data collection points are collected through various sensors and other signal collection devices in the NVH test bench.

[0045] Signal acquisition devices are provided at the NVH data acquisition points. These signal acquisition devices are used to collect NVH-related time domain signals during the operation of the powertrain. For example, vibration sensors are provided at some NVH data acquisition points to collect vibration signals at the points; microphones are provided at some NVH data acquisition points to collect noise signals at the points.

[0046] S202, extracting a time domain signal segment having abnormal knocking sound from a plurality of time domain signals.

[0047] For the time domain signals collected at different NVH collection points, the time domain signals with abnormal knocking noise can be screened out; then, the time domain signal segment where the abnormal knocking noise is located is extracted from the time domain signals with the abnormal knocking noise.

[0048] S203: Determine the source of abnormal knocking noise in the powertrain according to the time domain signal segment.

[0049] It is not difficult to understand that other locations adjacent to or associated with the source of the abnormal knocking noise may also exhibit abnormal vibrations and / or the noise at these locations may be mixed with abnormal knocking noises of varying degrees of clarity.

[0050] Therefore, the screened time domain signal segment with abnormal knocking noise may contain time domain signals belonging to the source of the abnormal knocking noise, or time domain signals belonging to other position points close to or associated with the source of the abnormal knocking noise.

[0051] The embodiment of the present application can screen the determined time domain signal segments, select the time domain signal segments with the most obvious knocking noise characteristics, and determine the knocking noise source in the powertrain with reference to the NVH data collection points corresponding to the time domain signal segments with the most obvious knocking noise characteristics.

[0052] The source of the knocking noise may be any component in the powertrain, or any position on any component in the powertrain. The corresponding relationship between the NVH data collection points and the components in the powertrain can be pre-calibrated before the test begins.

[0053] For example, an NVH data collection point set on the engine motor is used as an observation point to determine whether there is abnormal knocking noise in the engine motor. The presence of abnormal knocking noise in the engine motor can be determined by analyzing whether there is abnormal knocking noise in the time domain signal collected by the NVH data collection point. If there is abnormal knocking noise, the engine motor is the source of the abnormal knocking noise.

[0054] For another example, an NVH data collection point set at a certain position of the powertrain is used as an observation point to determine whether there is abnormal knocking noise in multiple components at that position (the correspondence between the position and the component can be pre-defined). By analyzing whether there is abnormal knocking noise in the time domain signal collected by the NVH data collection point, it can be determined whether any of the multiple components at that position has abnormal knocking noise; if there is abnormal knocking noise in the time domain signal, the multiple components at that position are regarded as the source of the abnormal knocking noise. In this case, the component determined as the source of the abnormal knocking noise can be further observed and analyzed.

[0055] In some embodiments, when determining the time domain signal segment with the most obvious abnormal knocking noise, it can be achieved in the following way: the time domain signal segment can be directly converted into audio, and the audio can be played to the test personnel, who can subjectively evaluate the obviousness of the abnormal knocking noise appearing in these audios, thereby determining the time domain signal segment with the most obvious abnormal knocking noise.

[0056] In summary, the method for identifying the source of abnormal knocking noise proposed in this application assembles the various components of the powertrain together according to the requirements of the whole vehicle, uses the NVH test bench to simulate the operating conditions of the powertrain in the vehicle, and in the process of simulating the operating conditions of the powertrain, collects time domain signals from different NVH data collection points, extracts time domain signal segments with abnormal knocking noises from these time domain signals, and each time domain signal segment shows the abnormal knocking noise of a certain component of the powertrain during the operation of the powertrain. The source of the abnormal knocking noise determined based on these time domain signal segments is more in line with the source of the abnormal knocking noise of the powertrain under the actual vehicle operating conditions. Compared with the identification of abnormal knocking noises of a single engine or transmission, it can detect the knocking problem at the assembly level in advance, and at the same time, it also eliminates the influence of other components of the whole vehicle except the powertrain, which is conducive to determining the true source of the abnormal knocking noise.

[0057] Based on the above embodiments, Figure 3 As shown, in the above step S202, "extracting the time domain signal segment with the abnormal knocking sound from the multiple time domain signals" includes the following steps: S301, performing time-frequency analysis on the time domain signal to obtain a time-frequency energy spectrum.

[0058] S302, determining a characteristic frequency segment where a peak value in the time-frequency energy spectrum is located; S303: extracting a signal segment corresponding to the characteristic frequency segment from the time domain signal as a time domain signal segment with abnormal knocking sound.

[0059] In an embodiment of the present application, a wavelet transform analysis method is used to perform time-frequency analysis on the time domain signal to obtain a power spectrum corresponding to the time domain signal or a time-frequency two-dimensional color energy spectrum corresponding to the time domain signal (i.e., the time-frequency energy spectrum in the above step S301).

[0060] The power spectrum shows the power distribution of the signal at different frequencies, that is, the distribution of the signal's energy at different frequencies.

[0061] The time-frequency energy spectrum can intuitively display the energy distribution and change process of the signal in the two dimensions of time and frequency, and reveal the change process of its frequency components over time.

[0062] In the embodiment of the present application, after obtaining the time-frequency energy spectrum corresponding to the time-domain signal, the characteristic frequency segment where the peak value in the spectrum is located is determined.

[0063] For example, the frequency at which the maximum peak in the spectrum is located is taken as the center frequency, and based on the preset bandwidth and the center frequency, the characteristic frequency segment at which the maximum peak is located is determined.

[0064] A bandpass filter can be used to extract a signal segment corresponding to a characteristic frequency segment from the time domain signal as the time domain signal segment with the abnormal knocking sound.

[0065] The time domain signal in the embodiment of the present application may be a vibration signal on the powertrain and / or a noise signal at different locations outside the powertrain.

[0066] It is important to understand that knocking noises are caused by abnormal contact or collision between objects. Collisions release energy quickly, and the energy carried by the signal increases significantly at the moment the knock occurs. In this embodiment, by performing time-frequency analysis on the time domain signal to obtain a time-frequency energy spectrum, focusing on the energy changes of the time domain signal, cutting out the characteristic frequency segments where the energy peaks appear, and determining the time domain signal segments where abnormal knocking sounds exist from the signal segments corresponding to these characteristic frequency segments. In this way, all signal segments that may exhibit abnormal knocking sound characteristics can be included for further analysis and accurate location of the source of the abnormal knocking sound; at the same time, redundant information in the time domain signal is discarded to reduce the workload of subsequent further analysis.

[0067] Based on the above embodiments, Figure 4 As shown, before "performing time-frequency analysis on the time domain signal to obtain a time-frequency energy spectrum" in the above step S301, the method for identifying the source of abnormal knocking sound further includes the following steps: S401, converting the time domain signal into a first audio frequency, so that a tester can make a subjective evaluation on whether there is an abnormal knocking sound in the first audio frequency; S402, if the subjective evaluation result corresponding to the time domain signal is that there is an abnormal knocking sound, then a step of performing time-frequency analysis on the time domain signal to obtain a time-frequency energy spectrum is executed.

[0068] For example, the vibration signals collected from various components of the powertrain are converted into audio, and the audio is played to the test personnel, who then make a subjective evaluation of whether there is abnormal knocking noise in the audio; the subjective evaluation result is the presence of abnormal knocking noise, or the absence of abnormal knocking noise; If the subjective evaluation result corresponding to a time domain signal is that there is an abnormal knocking sound, then continue to perform time-frequency analysis on the time domain signal to obtain the time-frequency energy spectrum corresponding to the time domain signal; If the subjective evaluation result corresponding to a time domain signal is that there is no abnormal knocking sound, the time domain signal is discarded.

[0069] Before objectively analyzing the time domain signal, the embodiment of the present application first screens the time domain signal through subjective analysis, which reduces the workload of objective signal analysis on the one hand, and considers the user's subjective feelings when identifying the abnormal sound source on the other hand, and identifies the abnormal sound source that affects the user's auditory perception for optimization.

[0070] On the basis of the above embodiment, when the tester makes a subjective evaluation on whether there is an abnormal knocking sound in the first audio, the tester may further record the abnormal sound characteristics of the abnormal knocking sound.

[0071] The abnormal sound characteristics can be understood as the sound characteristics of the abnormal knocking sound, which may include but are not limited to characteristics such as pitch and timbre.

[0072] The abnormal sound feature is affected by the frequency of the vibration signal / noise signal and changes with the frequency. For example, the higher the frequency, the higher the pitch of the sound, and the lower the frequency, the lower the pitch of the sound.

[0073] For example, some knocking noises appear as a "da da" sound, some appear as a "dang dang" sound, or even as a sharper knocking sound, or a duller knocking sound, and so on.

[0074] In this case, the above step S303 of "extracting the signal segment corresponding to the characteristic frequency segment from the time domain signal as the time domain signal segment with the knocking abnormal sound" can be implemented in the following way: converting the signal segment corresponding to each characteristic frequency segment into a second audio, so that the experimenter can determine the target audio that can show the target abnormal sound feature from all the second audios, and the target abnormal sound feature is the overall abnormal sound feature determined by the experimenter for the time domain signal; using the signal segment corresponding to the target audio as the time domain signal segment with the knocking abnormal sound For example, after obtaining multiple vibration signals and noise signals, these signals are converted into first audio signals, and then these first audio signals are played to the test personnel, who judge whether there is a knocking abnormal sound in each of the played first audio signals. If there is a knocking abnormal sound, the overall abnormal sound feature of the knocking abnormal sound in the first audio signal is recorded as the above-mentioned target abnormal sound feature. For example, the overall abnormal sound feature of the knocking abnormal sound is recorded as a "dangdang" sound; Then, for each vibration signal and noise signal with abnormal knocking noise, a time-frequency analysis is performed, and the characteristic frequency segment corresponding to each peak is determined from the time-frequency energy diagram, and the signal segment corresponding to each characteristic frequency segment is further intercepted from the vibration signal / noise signal; Then, each signal segment of the time domain signal with knocking noise is converted into a second audio, and the second audio is played to the experimenter. The experimenter subjectively judges whether the abnormal sound characteristics of the second audio are consistent with the target abnormal sound characteristics pre-recorded for the time domain signal, and selects a second audio with the most consistent abnormal sound characteristics from all the second audios as the target audio.

[0075] In this way, for each time domain signal with abnormal knocking sound, a target audio can be determined, and the signal segment corresponding to the target audio is used as the time domain signal segment with abnormal knocking sound.

[0076] Optionally, the experimenter may further screen the multiple target audios that have been determined, for example, screening out several target audios whose abnormal sound characteristics are most consistent with the "dangdang" sound.

[0077] In this way, several time domain signal segments where the knocking noise is most obvious can be determined.

[0078] Based on the above embodiments, Figure 5 As shown, the above step S202 of "determining the source of the abnormal knocking noise in the powertrain according to the time domain signal segment" includes the following steps: S501, calculating the energy value of the time domain signal segment.

[0079] The embodiment of the present application calculates the root mean square (RMS) of each time domain signal segment to obtain the energy of the abnormal knocking sound component in the time domain signal where the time domain signal segment is located. The embodiment of the present application records the RMS value of the time domain signal segment as the above energy value.

[0080] S502, taking the NVH data collection point corresponding to the time domain signal segment with the largest energy value as the target position point.

[0081] The time domain signal segment with the largest energy value is selected from multiple time domain signal segments, and the NVH data collection point corresponding to the time domain signal segment with the largest energy value (i.e., the NVH data collection point where the time domain signal to which the time domain signal segment belongs is collected) is used as the target position point.

[0082] S503: Determine the source of abnormal knocking noise in the powertrain according to the target position point.

[0083] In the embodiment of the present application, the NVH data collection points may include those set at the first type of collection points and the second type of collection points; The first type of collection point is used to place the vibration sensor, and the first type of collection point is located on the powertrain. The first type of collection point can be positioned on different components of the powertrain as needed, and the vibration signal on the first type of collection point is collected based on the vibration sensor.

[0084] The second type of collection points are used to place microphones. The second type of collection points are distributed in various directions of the powertrain and have a preset spatial distance from the powertrain, that is, the second type of collection points are not located on the powertrain, but are located around the powertrain. The microphone collects noise signals at the second type of collection points.

[0085] For example, vibration sensors are installed on the active and passive sides of the hybrid powertrain suspension, the engine block, cylinder head, fuel pump, timing system housing, hybrid transmission housing, etc.; microphones are arranged at a distance of 1m from each surface based on a cube that can envelop the entire hybrid powertrain.

[0086] In some embodiments, when the target position point is the NVH data collection point where a vibration sensor is set, the target position point can be determined as the position point where the knocking noise source in the powertrain is located, such as the knocking noise source is a position point on the engine cylinder head; or the component where the target position point is located can be determined as the knocking noise source in the powertrain, such as the knocking noise source is a cylinder of the engine.

[0087] In other embodiments, when the target position point is the NVH data collection point where a microphone is set, the direction represented by the target position point can be determined as the direction where the knocking noise source is located in the powertrain, and the component covered by the direction can be determined as the knocking noise source (the relationship between the direction and the component it covers can be pre-defined).

[0088] Based on the above embodiments, Figure 6 As shown, in the above step S203, "determining the source of the abnormal knocking noise in the powertrain according to the time domain signal segment" includes: S601, calculating the energy value of the time domain signal segment of the noise signal; S602, determining the NVH data collection point corresponding to the noise signal with the largest energy value to determine the target orientation; S603, selecting a target vibration signal from the plurality of vibration signals according to the target orientation; S604, performing a correlation analysis of signal fluctuations between the time domain signal segment of the target vibration signal and at least one of a cylinder pressure signal of a powertrain, an engine speed signal, and an acceleration signal of an engine speed; S605, selecting a time domain signal segment having the greatest correlation with signal fluctuations from the time domain signal segments of the plurality of target vibration signals; S606, taking the NVH data collection point corresponding to the time domain signal segment with the largest correlation of signal fluctuation as the location point of the knocking abnormal sound source.

[0089] In the embodiment of the present application, the energy value of the time domain signal segment corresponding to the noise signal is calculated, the time domain signal segment with the largest energy value is screened out, and the orientation of the NVH data acquisition point corresponding to the noise signal to which the time domain signal segment belongs is determined as the target orientation; Filter out vibration signals at a plurality of NVH data collection points set on the powertrain at the target orientation as target vibration signals; Perform signal fluctuation correlation analysis on the time domain signal segment of the target vibration signal and at least one of the cylinder pressure signal of the powertrain, the engine speed signal, and the acceleration signal of the engine speed; screen out the time domain signal segment with the greatest correlation in signal fluctuation; and use the NVH data collection point corresponding to the time domain signal segment with the greatest correlation in signal fluctuation as the location point of the knocking noise source.

[0090] The embodiment of the present application determines the orientation of the source of the abnormal knocking noise by analyzing the noise signal, and then analyzes the vibration conditions of each component of the powertrain at each orientation, and performs correlation analysis between the time domain signal segments of the vibration signal finally screened out and the operating status of each component of the powertrain, and finally determines the time domain signal segment with the greatest correlation, and uses the collection point corresponding to the time domain signal segment as the location point of the source of the abnormal knocking noise, thereby increasing the accuracy of identifying the source of the abnormal knocking noise.

[0091] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0092] In order to implement the above embodiment, the present application embodiment also proposes an electronic device 700, such as Figure 7 As shown, the electronic device 700 may specifically include: a memory 701, a processor 702, and a computer program stored in the memory 701 and executable on the processor 702. When the processor 702 executes the program, the steps of the abnormal knocking sound recognition method shown in the above embodiment are implemented.

[0093] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0094] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0095] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for identifying the source of abnormal knocking sound, characterized in that: The method comprises: Using the NVH test bench in the knocking abnormal sound source identification system, controlling the powertrain to run a simulated working condition, and obtaining a time domain signal at an NVH data collection point during the operation of the powertrain; Extracting a time domain signal segment having abnormal knocking sound from the multiple time domain signals; The source of abnormal knocking noise in the powertrain is determined according to the time domain signal segment.

2. The method according to claim 1, characterized in that The step of extracting a time domain signal segment having abnormal knocking sound from the plurality of time domain signals comprises: Performing time-frequency analysis on the time domain signal to obtain a time-frequency energy spectrum; Determine the characteristic frequency segment where the peak value in the time-frequency energy spectrum is located; A signal segment corresponding to the characteristic frequency segment is extracted from the time domain signal as the time domain signal segment with the abnormal knocking sound.

3. The method according to claim 2, characterized in that Before performing time-frequency analysis on the time domain signal to obtain the time-frequency energy spectrum, the method further includes: Converting the time domain signal into a first audio frequency, so that a tester can make a subjective evaluation on whether there is an abnormal knocking sound in the first audio frequency; If the subjective evaluation result corresponding to the time domain signal is that there is an abnormal knocking sound, the step of performing time-frequency analysis on the time domain signal to obtain a time-frequency energy spectrum is executed.

4. The method according to claim 3, characterized in that The step of extracting the signal segment corresponding to the characteristic frequency segment from the time domain signal as the time domain signal segment with the abnormal knocking sound comprises: For each of the time domain signals having abnormal knocking sounds, extracting a signal segment corresponding to each of the characteristic frequency segments from the time domain signal; Converting the signal segment corresponding to each of the characteristic frequency segments into a second audio frequency, so that the experimenter can determine a target audio frequency that can exhibit a target abnormal sound feature from all of the second audio frequencies, wherein the target abnormal sound feature is an overall abnormal sound feature determined by the experimenter for the time domain signal; The signal segment corresponding to the target audio is used as the time domain signal segment with the abnormal knocking sound.

5. The method according to claim 1, characterized in that Determining the source of the abnormal knocking noise in the powertrain according to the time domain signal segment includes: Calculating the energy value of the time domain signal segment; The NVH data acquisition point corresponding to the time domain signal segment with the largest energy value is used as the target position point; According to the target position point, a source of abnormal knocking noise in the power assembly is determined.

6. The method according to claim 1, characterized in that Determining the source of the abnormal knocking noise in the powertrain according to the time domain signal segment includes: Performing a correlation analysis of signal fluctuations between the time domain signal segment and at least one of a cylinder pressure signal of the powertrain, an engine speed signal, and an acceleration signal of the engine speed; Filtering out a time domain signal segment having the greatest correlation with signal fluctuations from the plurality of time domain signal segments; The NVH data collection point corresponding to the time domain signal segment with the largest correlation of the signal fluctuation is used as the target position point; According to the target position point, a source of abnormal knocking noise in the power assembly is determined.

7. The method according to claim 1, characterized in that The time domain signal includes a vibration signal and a noise signal; there is a preset spatial distance between the NVH data collection point corresponding to the noise signal and the powertrain, and the NVH data collection point is set at different positions of the powertrain; the NVH data collection point corresponding to the vibration signal is set on the powertrain; Determining the source of the abnormal knocking noise in the powertrain according to the time domain signal segment includes: Calculating the energy value of the time domain signal segment of the noise signal; Determine the NVH data collection point corresponding to the noise signal with the largest energy value, so as to determine the target position of the knocking noise source; According to the target orientation, selecting a target vibration signal from the plurality of vibration signals; Performing a correlation analysis of signal fluctuations between the time domain signal segment of the target vibration signal and at least one of a cylinder pressure signal of the powertrain, an engine speed signal, and an acceleration signal of the engine speed; Selecting a time domain signal segment with the greatest correlation of signal fluctuations from a plurality of time domain signal segments of the target vibration signal; The NVH data collection point corresponding to the time domain signal segment with the largest correlation of the signal fluctuation is used as the location point of the knocking noise source.

8. A system for identifying the source of abnormal knocking sound, characterized in that: The system includes: an NVH test bench and a powertrain of a vehicle; The NVH test bench includes a test bench, a peripheral function module, a vibration sensor, a microphone, and a calibration control module; The powertrain is installed on the test bench; The peripheral function module is connected to a corresponding port on the powertrain and is used to provide peripheral functions for the powertrain so that the powertrain can operate; The vibration sensor is arranged on the power assembly; The microphones are arranged at different positions of the power assembly, and there is a preset spatial distance between the microphones and the power assembly; The data acquisition and analysis device is connected to the vibration sensor and the microphone, and is used to collect vibration signals and noise signals; The calibration control module is connected to the control unit of the powertrain and is used to control the powertrain to run a simulated operating condition.

9. The system according to claim 8, characterized in that The system also includes a pressure sensor and / or a speed acquisition wire; The pressure sensor is arranged in the engine cylinder of the powertrain; The data acquisition and analysis device is connected to the pressure sensor and is used to acquire the cylinder pressure signal of the powertrain; and / or; One end of the speed acquisition wire is connected to a signal line of an engine speed sensor in the powertrain; The other end of the speed acquisition wire is connected to the data acquisition and analysis device, and is used to acquire the engine speed signal and the acceleration signal of the engine speed of the powertrain.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the method for identifying the source of abnormal knocking sound as described in any one of claims 1 to 7 are implemented.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method for identifying the source of abnormal knocking sound as described in any one of claims 1 to 7 are implemented.

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