Method and device for determining engine status

Abstract

This application discloses a method and device for determining an engine state. The method comprises obtaining a vibration signal from a cylinder to be inspected in the engine; processing the vibration signal to obtain a harmonic vibration amplitude; and determining that the engine state is a misfire fault state if the harmonic vibration amplitude is greater than a standard vibration amplitude. In this manner, the vibration signal from the cylinder to be inspected in the engine is processed to obtain a resonant vibration amplitude. The resonant vibration amplitude is then compared with the standard vibration amplitude to determine whether the engine is in a misfire fault state. This method can accurately identify an engine in a misfire fault state, improving the accuracy of identifying the engine's state and thereby effectively protecting the engine.

Description

Technical Field

[0001] The present application relates to the field of engine technology, and in particular to a method and device for determining an engine state. Background Art

[0002] Engine misfire can cause unignited combustible gas to enter the after-treatment device along with the exhaust. Under heavy load conditions, the engine exhaust temperature is high, which will ignite this combustible gas, causing the temperature of the after-treatment device to increase sharply, causing damage, and even causing the vehicle to spontaneously combust, posing a huge safety hazard.

[0003] Currently, engine misfire diagnosis is performed based on the change in crankshaft speed. This method requires a large amount of data and cannot accurately diagnose engine misfire, resulting in a low recognition accuracy rate for engine misfire diagnosis. Summary of the Invention

[0004] In view of this, the present application provides a method and device for determining an engine state, which can improve the accuracy of identifying an engine misfire state.

[0005] To solve the above problems, the technical solutions provided by this application are as follows:

[0006] In a first aspect, the present application provides a method for determining an engine state, the method comprising:

[0007] Acquiring a vibration signal of a cylinder to be tested of the engine;

[0008] Processing the vibration signal to obtain a harmonic vibration amplitude;

[0009] If the harmonic vibration amplitude is greater than the standard vibration amplitude, it is determined that the state of the engine is a misfire fault state.

[0010] In one possible implementation, the harmonic vibration amplitude includes a first harmonic vibration amplitude and a second harmonic vibration amplitude, the standard vibration amplitude includes a first standard vibration amplitude and a second standard vibration amplitude, and if the harmonic vibration amplitude is greater than the standard vibration amplitude, determining that the engine is in a misfire fault state includes:

[0011] If the first harmonic vibration amplitude is greater than the first standard vibration amplitude and the second harmonic vibration amplitude is greater than the second standard vibration amplitude, determining that the state of the engine is a single-cylinder misfire fault state;

[0012] If the first harmonic vibration amplitude is not greater than the first standard vibration amplitude and the second harmonic vibration amplitude is greater than the second standard vibration amplitude, it is determined that the state of the engine is a two-cylinder misfire fault state.

[0013] In one possible implementation, after determining that the state of the engine is a misfire fault state, the method further includes:

[0014] performing low-pass filtering on the first harmonic vibration amplitude and the second harmonic vibration amplitude to obtain a filtered vibration amplitude;

[0015] Obtaining the ignition top dead center of the cylinder to be tested;

[0016] determining an energy detection window according to the ignition top dead center;

[0017] Calculating an average filtered amplitude of the filtered vibration amplitudes in the energy detection window;

[0018] The ratio of the average amplitude to the standard average amplitude is used as the detection value;

[0019] The misfiring cylinder is determined based on a comparison result between the detection value and a preset threshold.

[0020] In one possible implementation, determining the energy detection window according to the ignition top dead center includes:

[0021] The interval from the ignition top dead center to 30 degrees after the ignition top dead center is set as the energy detection window.

[0022] In one possible implementation, the method further includes:

[0023] If the state of the engine is a misfire fault state, an alarm message is issued.

[0024] In a second aspect, the present application provides a device for determining an engine state, the device comprising:

[0025] A first acquisition module is used to acquire a vibration signal of a cylinder to be detected of the engine;

[0026] A first processing module is used to process the vibration signal to obtain a harmonic vibration amplitude;

[0027] The first determination module is configured to determine that the engine is in a misfire fault state if the harmonic vibration amplitude is greater than a standard vibration amplitude.

[0028] In one possible implementation, the harmonic vibration amplitude includes a first harmonic vibration amplitude and a second harmonic vibration amplitude, the standard vibration amplitude includes a first standard vibration amplitude and a second standard vibration amplitude, and the first determining module is specifically configured to:

[0029] If the first harmonic vibration amplitude is greater than the first standard vibration amplitude and the second harmonic vibration amplitude is greater than the second standard vibration amplitude, determining that the state of the engine is a single-cylinder misfire fault state;

[0030] If the first harmonic vibration amplitude is not greater than the first standard vibration amplitude and the second harmonic vibration amplitude is greater than the second standard vibration amplitude, it is determined that the state of the engine is a two-cylinder misfire fault state.

[0031] In one possible implementation, after determining that the state of the engine is a misfire fault state, the device further includes:

[0032] a second processing module, configured to perform low-pass filtering on the first harmonic vibration amplitude and the second harmonic vibration amplitude to obtain a filtered vibration amplitude;

[0033] A second acquisition module is used to obtain the ignition top dead center of the cylinder to be tested;

[0034] A second determining module is used to determine an energy detection window according to the ignition top dead center;

[0035] A calculation module, configured to calculate an average filtered amplitude of the filtered vibration amplitudes in the energy detection window;

[0036] a detection value acquisition module, configured to use the ratio of the average amplitude to the standard average amplitude as a detection value;

[0037] The third determining module is configured to determine the misfiring cylinder according to a comparison result between the detection value and a preset threshold.

[0038] In a possible implementation, the second determining module is specifically configured to set an interval from the ignition top dead center to 30 degrees after the ignition top dead center as an energy detection window.

[0039] In one possible implementation, the device further includes:

[0040] The alarm module is used to issue an alarm message if the state of the engine is a misfire fault state.

[0041] In a third aspect, the present application provides an engine status determination device, comprising: a processor, a memory, and a system bus;

[0042] The processor and the memory are connected via the system bus;

[0043] The memory is used to store one or more programs, and the one or more programs include instructions. When the instructions are executed by the processor, the processor executes the method for determining the engine status described in the first aspect above.

[0044] In a fourth aspect, the present application provides a computer-readable storage medium, in which instructions are stored. When the instructions are executed on a terminal device, the terminal device executes the method for determining the engine status described in the first aspect above.

[0045] It can be seen that this application has the following beneficial effects:

[0046] This application provides a method and device for determining an engine state. The method obtains a vibration signal from a cylinder to be tested in the engine; processes the vibration signal to obtain a harmonic vibration amplitude; and if the harmonic vibration amplitude is greater than a standard vibration amplitude, determines that the engine state is a misfire fault state. In this manner, the vibration signal from the cylinder to be tested in the engine is processed to obtain a resonant vibration amplitude. The resonant vibration amplitude is compared with the standard vibration amplitude to determine whether the engine is in a misfire fault state. This method accurately identifies the engine as being in a misfire fault state, improves the accuracy of identifying the engine's state, and thus effectively protects the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A flow chart of a method for determining an engine status provided in an embodiment of the present application;

[0048] Figure 2 A schematic diagram of the structure of a system for determining an engine state provided in an embodiment of the present application;

[0049] Figure 3 A comparison chart of the 0.5 harmonic vibration amplitude and the 1 harmonic vibration amplitude of an engine in a normal combustion state and the 0.5 harmonic vibration amplitude and the 1 harmonic vibration amplitude of an engine in a single-cylinder misfire fault state provided by an embodiment of the present application;

[0050] Figure 4 A schematic diagram of the engine status diagnosis process provided in an embodiment of the present application;

[0051] Figure 5 A schematic diagram of a flow chart for determining a misfiring cylinder provided in an embodiment of the present application;

[0052] Figure 6 This is a 2-cylinder combustion excitation spectrum diagram provided in the embodiment of the present application;

[0053] Figure 7 This is a 5-cylinder combustion excitation spectrum diagram provided in the embodiment of the present application;

[0054] Figure 8 A schematic diagram of an energy detection window provided in an embodiment of the present application;

[0055] Figure 9A schematic structural diagram of a device for determining engine status provided in an embodiment of the present application. DETAILED DESCRIPTION

[0056] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0057] In this application, the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0058] In order to facilitate understanding and explanation of the technical solutions provided by the embodiments of the present application, the background technology of the present application will be described below.

[0059] Current methods for diagnosing vehicle engine misfires involve obtaining the engine's angular velocity using an angular velocity sensor and the acceleration associated with the vehicle's vertical vibration using an acceleration sensor. The acceleration is then compared with an acceleration threshold to determine whether the vehicle is traveling on an undulating road and to diagnose whether a misfire has occurred. Misfire diagnostic results are obtained in a first test environment where the vehicle is traveling on an undulating road without a forced misfire, and in a second test environment where the vehicle is traveling on an undulating road with a forced misfire. Current methods often rely on changes in crankshaft speed, resulting in a high algorithm workload, limited ECU processing power, and delayed processing results. Consequently, the accuracy of identifying whether the engine is in a misfire state is low, making it ineffective in protecting the engine.

[0060] Based on this, an embodiment of the present application provides a method and apparatus for determining an engine state, which obtains a vibration signal from a cylinder to be tested in the engine; processes the vibration signal to obtain a harmonic vibration amplitude; and if the harmonic vibration amplitude is greater than a standard vibration amplitude, determines that the engine state is a misfire fault state. In this way, the vibration signal from the cylinder to be tested in the engine is processed to obtain a resonant vibration amplitude, and the resonant vibration amplitude is compared with the standard vibration amplitude to determine whether the engine is in a misfire fault state. This can accurately identify that the engine is in a misfire fault state, improve the accuracy of identifying the engine's current state, and effectively protect the engine.

[0061] In order to facilitate understanding of the technical solution provided by the embodiment of the present application, a method and device for determining the engine status provided by the embodiment of the present application are described below with reference to the accompanying drawings.

[0062] First, it should be noted that the method for determining the engine state provided in the embodiment of the present application is applied to a vehicle having an engine structure, and the embodiment of the present application is not limited to a specific type of vehicle. Figure 1 , this figure is a flow chart of a method for determining the engine status provided in an embodiment of the present application, and the method specifically includes S101-S103.

[0063] S101: Acquire a vibration signal of a cylinder to be detected of the engine.

[0064] The present application does not limit the specific method of obtaining the vibration signal. In one possible implementation, the vibration signal can be obtained through a knock sensor. Figure 2 This figure is a schematic diagram of the structure of an engine status determination system provided by an embodiment of the present application. The system primarily comprises a knock sensor, an ECU, a crankshaft speed sensor, and a camshaft phase sensor. The knock sensor is used to collect engine body vibration signals, namely, vibration signals from the engine cylinders; the ECU is used for data processing and storage; and the crankshaft speed sensor and camshaft phase sensor are used to identify ignition top dead center.

[0065] For example, two knock sensors are typically installed on the upper portion of a six-cylinder engine, one on cylinders 2 and 5. These sensors collect vibration signals at these sampling points. The knock sensors transmit these signals to the ECU in real time.

[0066] S102: Process the vibration signal to obtain harmonic vibration amplitude.

[0067] In one possible implementation, processing the vibration signal includes performing a Fourier transform on the vibration signal to convert the collected time-domain signal into a frequency-domain signal. The harmonic vibration amplitudes include a first harmonic vibration amplitude and a second harmonic vibration amplitude. Taking a 6-cylinder engine as an example, during normal engine operation, its 0.5 harmonic and 1 harmonic are balanced, and the corresponding 0.5 harmonic vibration amplitudes and 1 harmonic vibration amplitudes are relatively small. The first harmonic vibration amplitude corresponds to the 0.5 harmonic vibration amplitude, and the second harmonic vibration amplitude corresponds to the 1 harmonic vibration amplitude. Harmonics are multiples or fractions of the rotational frequency; a harmonic of 0.5 represents vibration at 0.5 times the rotational frequency, and a harmonic of 1 represents vibration at 1 times the rotational frequency. If the engine is in a misfire state, the combustion excitation of the misfired cylinder becomes smaller than that of other cylinders, disrupting the vibration balance between the 0.5 harmonic and 1 harmonic of the engine, and increasing the 0.5 harmonic vibration amplitude and the 1 harmonic vibration amplitude.

[0068] S103: If the harmonic vibration amplitude is greater than the standard vibration amplitude, it is determined that the state of the engine is a misfire fault state.

[0069] If the above-mentioned harmonic vibration amplitude is greater than the standard vibration amplitude, it indicates that the engine is in a misfire fault state, wherein the standard vibration amplitude is a preset multiple value of the harmonic vibration amplitude obtained in the previous cycle, that is, a preset multiple value of the vibration amplitude obtained by the engine under normal combustion state.

[0070] For details, see Figure 3 , Figure 3 This is a comparison of the 0.5 harmonic vibration amplitude and 1 harmonic vibration amplitude of the engine in a normal combustion state and the 0.5 harmonic vibration amplitude and 1 harmonic vibration amplitude of the engine in a single-cylinder misfire fault state in the embodiment of the present application. The normal combustion state means that the engine does not misfire. Figure 3In the text, the 0.5 harmonic vibration amplitude is abbreviated as "0.5 harmonic" and the 1 harmonic vibration amplitude is abbreviated as "1 harmonic." It can be seen that when the engine is in a single-cylinder misfire fault state, its 0.5 harmonic vibration amplitude is 10 times higher than the 0.5 harmonic vibration amplitude in the normal combustion state, and the 1 harmonic vibration amplitude is 2 times higher than the 1 harmonic vibration amplitude in the normal combustion state. The difference is large, and the difference is more obvious when the engine is running at high load. The engine vibration signal is periodically collected and processed, and the obtained results are compared with the standard vibration amplitude. Accordingly, the standard vibration amplitude also includes a first standard vibration amplitude and a second standard vibration amplitude. The first standard vibration amplitude is 5 times the 0.5 harmonic vibration amplitude in the normal combustion state, and the second standard vibration amplitude is 1.5 times the 1 harmonic vibration amplitude in the normal combustion state. If at least one of the first harmonic vibration amplitude and the second harmonic vibration amplitude obtained after Fourier transform of the vibration signals collected by the two explosion sensors is much larger than the standard vibration amplitude, for example, the first harmonic vibration signal is significantly larger than the first standard vibration signal, and / or the second harmonic vibration signal is significantly larger than the second standard vibration signal, it indicates that the engine is in a misfire fault state.

[0071] In one possible implementation, the method further includes: if the engine is in a misfire state, issuing an alarm message. The embodiment of the present application does not limit the specific form of the alarm message, including but not limited to voice alarm and text alarm, which can be selected according to actual needs.

[0072] As an example, take the cylinders 2 and 5 to be tested of a 6-cylinder engine as an example. Figure 4 , Figure 4 A schematic diagram of the diagnostic process of the engine status provided in an embodiment of the present application. The vibration signal of cylinder 2 is Fourier transformed into the first harmonic vibration amplitude (i.e., 0.5 harmonic vibration amplitude) and the second harmonic vibration amplitude (i.e., 1 harmonic vibration amplitude) of cylinder 2. If it is determined that the 0.5 harmonic vibration amplitude is less than or equal to the first standard vibration amplitude, and the 1 harmonic vibration amplitude is less than or equal to the second standard vibration amplitude, the vibration signal of cylinder 5 is Fourier transformed into the first harmonic vibration amplitude (i.e., 0.5 harmonic vibration amplitude) and the second harmonic vibration amplitude (i.e., 1 harmonic vibration amplitude) of cylinder 5, and a judgment is made. If the 0.5 harmonic vibration amplitude of cylinder 5 is less than or equal to the first standard vibration amplitude, and the 1 harmonic vibration amplitude is less than or equal to the second standard vibration amplitude, the engine is in a normal combustion state. If the 0.5 harmonic vibration amplitude of cylinder 2 is greater than the first standard vibration amplitude, or the 1 harmonic vibration amplitude of cylinder 2 is greater than the second standard vibration amplitude, or the 0.5 harmonic vibration amplitude of cylinder 5 is greater than the first standard vibration amplitude, or the 1 harmonic vibration amplitude of cylinder 5 is greater than the second standard vibration amplitude, it indicates that the engine is in a misfire fault state.

[0073] In one possible implementation, the harmonic vibration amplitude includes a first harmonic vibration amplitude and a second harmonic vibration amplitude, and the standard vibration amplitude includes a first standard vibration amplitude and a second standard vibration amplitude. If the harmonic vibration amplitude is greater than the standard vibration amplitude, then determining that the state of the engine is a misfire fault state includes: if the first harmonic vibration amplitude is greater than the first standard vibration amplitude and the second harmonic vibration amplitude is greater than the second standard vibration amplitude, then determining that the state of the engine is a single-cylinder misfire fault state; if the first harmonic vibration amplitude is not greater than the first standard vibration amplitude and the second harmonic vibration amplitude is greater than the second standard vibration amplitude, then determining that the state of the engine is a dual-cylinder misfire fault state.

[0074] By determining the 0.5 harmonic vibration amplitude and the 1 harmonic vibration amplitude, it is possible to accurately identify whether the engine is in a single-cylinder misfire fault state or a dual-cylinder misfire fault state. Specifically, the engine cylinders to be tested have a mapping relationship. At the 0.5 harmonic, cylinder 1 corresponds to cylinder 6, cylinder 2 corresponds to cylinder 5, and cylinder 3 corresponds to cylinder 4. If the engine is in a dual-cylinder misfire fault state, and the two cylinders are cylinders 1 and 6, or cylinders 2 and 5, or cylinders 3 and 4, the 0.5 harmonic vibration balance will not be disturbed. However, the 1 harmonic vibration balance will still be disturbed. Therefore, if the 0.5 harmonic vibration amplitude is not greater than the first standard vibration amplitude, and the 1 harmonic vibration amplitude is greater than the second standard vibration amplitude, the engine state is determined to be a dual-cylinder misfire fault state. Determining the specific state of the engine misfire fault allows for rapid engine repair.

[0075] Based on the relevant contents of S101-S103 above, it can be known that the vibration signal of the cylinder to be tested of the engine is processed to obtain the resonant vibration amplitude, and the resonant vibration amplitude is compared with the standard vibration amplitude to determine whether the engine is in a misfire fault state. This can accurately identify that the engine is in a misfire fault state, thereby improving the accuracy of identifying the engine's state and effectively protecting the engine.

[0076] The following describes the process of determining a specific misfiring cylinder provided in an embodiment of the present application.

[0077] See also Figure 5 , Figure 5This is a flow chart illustrating a misfiring cylinder. In one possible implementation, after determining that the engine is in a misfire state, the method further includes: performing low-pass filtering on the first harmonic vibration amplitude and the second harmonic vibration amplitude to obtain a filtered vibration amplitude; obtaining the ignition top dead center of the cylinder to be detected; determining an energy detection window based on the ignition top dead center; calculating an average filtered amplitude of the filtered vibration amplitude within the energy detection window; using the ratio of the average amplitude to a standard average amplitude as a detection value; and determining the misfiring cylinder based on a comparison of the detection value with a preset threshold.

[0078] It should be noted that the preset threshold value may include a preset upper threshold value and a preset lower threshold value, and the preset upper threshold value and the preset lower threshold value may be obtained through calibration. During the actual operation of the sensor, the response results are different at different speeds and different working conditions, resulting in greater difficulty in determining the preset upper threshold value and the preset lower threshold value of the cylinder to be detected at different speeds and different working conditions. In the embodiment of the present application, a dimensionless parameter, the ratio of the average amplitude of the cylinder to be detected to the standard average amplitude of the standard cylinder 1, is introduced. Because the ratio of the average amplitude of different cylinders to the corresponding standard average amplitude of the standard cylinder 1 is only related to the structure of the engine and does not change with the speed and working conditions, it can greatly reduce the calibration time and improve the efficiency of determining the engine misfiring cylinder.

[0079] After determining that the engine is in a misfire fault state, in order to reduce the risk of engine combustion caused by high temperature, the engine quickly reduces the load and enters the limp state, and at the same time confirms the specific misfire cylinder of the engine.

[0080] See also Figure 6 and Figure 7 , Figure 6 This is a 2-cylinder combustion excitation spectrum diagram provided in the embodiment of this application. Figure 7 This is a 5-cylinder combustion excitation spectrum diagram provided by the embodiment of this application. The combustion excitation energy is mainly concentrated in the low frequency, and the harmonic vibration amplitude is low-pass filtered from 1Hz to 500Hz. The ignition top dead center of the cylinder to be tested is determined based on the crankshaft speed sensor and camshaft phase sensor. Figure 8 , Figure 8 A schematic diagram of an energy detection window provided for an embodiment of the present application. In one possible implementation, determining the energy detection window based on the ignition top dead center includes setting the interval from the ignition top dead center to 30 degrees after the ignition top dead center as the energy detection window. If the engine is in a misfire fault state, the corresponding vibration energy within the energy detection window of the misfire cylinder will be significantly reduced, so the calculated average amplitude of the vibration amplitude of the energy detection window angle interval of the cylinder to be detected is obtained. The calculation formula of the average amplitude is shown in the following formula (1).

[0081]

[0082] Among them, A j is the average vibration acceleration within the energy detection window of cylinder j, j = 1, 2, 3, 4, 5, 6.

[0083] a i is the vibration acceleration value at i degrees after ignition top dead center, i = 1, 2...30.

[0084] The average value A in the energy detection window of the cylinder to be detected j The ratio of the average value A1 of the cylinder 1 is used as the detection value. j The calculation formula is shown in the following formula (2).

[0085]

[0086] Preset upper and lower thresholds are obtained through calibration. In one possible implementation, the misfiring cylinder is determined based on the comparison of the detection value with the preset threshold. Specifically, when the engine is in a single-cylinder misfire state, if the detection value of a cylinder to be detected is less than the preset lower threshold, the cylinder to be detected is determined to be the misfiring cylinder; if the detection values ​​of all five cylinders to be detected are greater than the preset upper threshold, standard cylinder 1 is determined to be the misfiring cylinder. When the engine is in a dual-cylinder misfire state, if the detection values ​​of two of the five cylinders to be detected are less than the preset lower threshold, the two cylinders to be detected with detection values ​​less than the preset lower threshold are determined to be the misfiring cylinders; if the detection values ​​of four of the five cylinders to be detected are greater than the preset upper threshold, standard cylinder 1 and the cylinders to be detected with detection values ​​not greater than the preset upper threshold are determined to be the misfiring cylinders. Vibration data from both knock sensors is used in the diagnosis of the engine's misfiring cylinders, improving diagnostic efficiency. In a possible implementation, the ignition top dead center of the cylinder to be detected determined based on the crankshaft speed sensor and the camshaft phase sensor is described.

[0087] The engine is equipped with a crankshaft speed sensor and a camshaft phase sensor. These sensors use crankshaft and camshaft tooth signal pulses to determine engine speed and ignition top dead center (TDC). Specifically, the crankshaft is divided into 60 equal sections, each containing 58 teeth and two sections without teeth. The crankshaft speed sensor identifies the tooth-free sections. The camshaft has five teeth, four of which are spaced 90 degrees apart. The fifth tooth is spaced 15 degrees apart from one of the teeth. The camshaft phase sensor identifies the position of the fifth tooth. Based on the identification of the tooth-free section and the fifth tooth, TDC (toc) can be determined, i.e., the TDC angle.

[0088] In one possible implementation, after the target misfiring cylinder is identified, an alert is sent to the user. The ECU can then use a correction algorithm to correct the misfiring cylinder. If the correction resolves the misfire, the engine returns to normal operation. If the correction is not possible, the engine remains in limp mode and continues to send alerts to the user, prompting them to initiate repairs as soon as possible.

[0089] The above embodiment of the present application provides a method for determining the engine misfire state based on the above. Next, an apparatus for determining the engine misfire state provided in the embodiment of the present application is described. The apparatus performs the above Figure 1 The method shown in FIG. 1 is used to describe the function of the engine misfire state determination device. The structure diagram of the engine misfire state determination device is shown in FIG. Figure 9 As shown, it includes: a first acquisition module 901, a first processing module 902, and a first determination module 903:

[0090] A first acquisition module 901 is used to acquire a vibration signal of a cylinder to be detected of the engine;

[0091] A first processing module 902 is used to process the vibration signal to obtain a harmonic vibration amplitude;

[0092] The first determining module 903 is configured to determine that the engine is in a misfire fault state if the harmonic vibration amplitude is greater than a standard vibration amplitude.

[0093] In one possible implementation, the harmonic vibration amplitude includes a first harmonic vibration amplitude and a second harmonic vibration amplitude, the standard vibration amplitude includes a first standard vibration amplitude and a second standard vibration amplitude, and the first determining module 903 is specifically configured to:

[0094] If the first harmonic vibration amplitude is greater than the first standard vibration amplitude and the second harmonic vibration amplitude is greater than the second standard vibration amplitude, determining that the state of the engine is a single-cylinder misfire fault state;

[0095] If the first harmonic vibration amplitude is not greater than the first standard vibration amplitude and the second harmonic vibration amplitude is greater than the second standard vibration amplitude, it is determined that the state of the engine is a two-cylinder misfire fault state.

[0096] In one possible implementation, after determining that the state of the engine is a misfire fault state, the device further includes:

[0097] a second processing module, configured to perform low-pass filtering on the first harmonic vibration amplitude and the second harmonic vibration amplitude to obtain a filtered vibration amplitude;

[0098] A second acquisition module is used to obtain the ignition top dead center of the cylinder to be tested;

[0099] A second determining module is used to determine an energy detection window according to the ignition top dead center;

[0100] A calculation module, configured to calculate an average filtered amplitude of the filtered vibration amplitudes in the energy detection window;

[0101] a detection value acquisition module, configured to use the ratio of the average amplitude to the standard average amplitude as a detection value;

[0102] The third determining module is configured to determine the misfiring cylinder according to a comparison result between the detection value and a preset threshold.

[0103] In a possible implementation, the second determining module is specifically configured to set an interval from the ignition top dead center to 30 degrees after the ignition top dead center as an energy detection window.

[0104] In one possible implementation, the device further includes:

[0105] The alarm module is used to issue an alarm message if the state of the engine is a misfire fault state.

[0106] An embodiment of the present application provides a device for determining the state of an engine, which includes a first acquisition module, a first processing module, and a first determination module. The first acquisition module is used to acquire the vibration signal of the cylinder to be detected of the engine; the first processing module is used to process the vibration signal to obtain the harmonic vibration amplitude; the first determination module is used to determine that the state of the engine is a misfire fault state if the harmonic vibration amplitude is greater than the standard vibration amplitude. In this way, the vibration signal of the cylinder to be detected of the engine is processed to obtain the resonant vibration amplitude, and the resonant vibration amplitude is compared with the standard vibration amplitude to determine whether the engine is in a misfire fault state. It is possible to accurately identify that the engine is in a misfire fault state, thereby improving the accuracy of identifying the state of the engine, and thus effectively protecting the engine.

[0107] Based on the determination of an engine state provided by the above method embodiment, an embodiment of the present application further provides a device for determining an engine state, comprising: a processor, a memory, and a system bus;

[0108] The processor and the memory are connected via the system bus;

[0109] The memory is used to store one or more programs, and the one or more programs include instructions. When the instructions are executed by the processor, the processor executes the method for determining the engine status described in any one of the above embodiments.

[0110] A computer-readable storage medium is provided based on the above method embodiment, and the computer-readable storage medium stores instructions. When the instructions are executed on a terminal device, the terminal device executes a method for determining an engine status as described in any one of the above embodiments.

[0111] Each embodiment in this specification is described in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple. For relevant parts, refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without expending creative work.

[0112] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0113] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for determining an engine state, characterized in that: The method comprises: Acquiring a vibration signal of a cylinder to be tested of the engine; Processing the vibration signal to obtain a harmonic vibration amplitude; If the harmonic vibration amplitude is greater than the standard vibration amplitude, determining that the state of the engine is a misfire fault state; The harmonic vibration amplitude includes a first harmonic vibration amplitude and a second harmonic vibration amplitude, the standard vibration amplitude includes a first standard vibration amplitude and a second standard vibration amplitude, and if the harmonic vibration amplitude is greater than the standard vibration amplitude, determining that the state of the engine is a misfire fault state includes: If the first harmonic vibration amplitude is greater than the first standard vibration amplitude and the second harmonic vibration amplitude is greater than the second standard vibration amplitude, determining that the state of the engine is a single-cylinder misfire fault state; If the first harmonic vibration amplitude is not greater than the first standard vibration amplitude and the second harmonic vibration amplitude is greater than the second standard vibration amplitude, determining that the state of the engine is a two-cylinder misfire fault state; After determining that the state of the engine is a misfire fault state, the method further includes: performing low-pass filtering on the first harmonic vibration amplitude and the second harmonic vibration amplitude to obtain a filtered vibration amplitude; Obtaining the ignition top dead center of the cylinder to be tested; determining an energy detection window according to the ignition top dead center; Calculating an average amplitude of the filtered vibration amplitudes in the energy detection window; The ratio of the average amplitude to the standard average amplitude is used as the detection value; The misfiring cylinder is determined based on a comparison result between the detection value and a preset threshold.

2. The method according to claim 1, characterized in that The determining of the energy detection window according to the ignition top dead center includes: The interval from the ignition top dead center to 30 degrees after the ignition top dead center is set as the energy detection window.

3. The method according to claim 1, characterized in that The method further comprises: If the state of the engine is a misfire fault state, an alarm message is issued.

4. A device for determining an engine state, characterized in that: The device comprises: A first acquisition module is used to acquire a vibration signal of a cylinder to be detected of the engine; A first processing module is used to process the vibration signal to obtain a harmonic vibration amplitude; a first determining module, configured to determine that the state of the engine is a misfire fault state if the harmonic vibration amplitude is greater than a standard vibration amplitude; The harmonic vibration amplitude includes a first harmonic vibration amplitude and a second harmonic vibration amplitude, the standard vibration amplitude includes a first standard vibration amplitude and a second standard vibration amplitude, and the first determining module is specifically configured to: If the first harmonic vibration amplitude is greater than the first standard vibration amplitude and the second harmonic vibration amplitude is greater than the second standard vibration amplitude, determining that the state of the engine is a single-cylinder misfire fault state; If the first harmonic vibration amplitude is not greater than the first standard vibration amplitude and the second harmonic vibration amplitude is greater than the second standard vibration amplitude, determining that the state of the engine is a two-cylinder misfire fault state; After determining that the state of the engine is a misfire fault state, the device further includes: a second processing module, configured to perform low-pass filtering on the first harmonic vibration amplitude and the second harmonic vibration amplitude to obtain a filtered vibration amplitude; A second acquisition module is used to obtain the ignition top dead center of the cylinder to be tested; A second determining module is used to determine an energy detection window according to the ignition top dead center; A calculation module, configured to calculate an average amplitude of the filtered vibration amplitudes in the energy detection window; a detection value acquisition module, configured to use the ratio of the average amplitude to the standard average amplitude as a detection value; The third determining module is configured to determine the misfiring cylinder according to a comparison result between the detection value and a preset threshold.

5. The device according to claim 4, characterized in that The second determining module is specifically configured to set the interval from the ignition top dead center to 30 degrees after the ignition top dead center as the energy detection window.

6. The device according to claim 4, characterized in that The device further comprises: The alarm module is used to issue an alarm message if the state of the engine is a misfire fault state.

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