Engine misfire detection method and device

Abstract

This application provides an engine misfire detection method and device, applicable to the automotive field. The method comprises: collecting an engine speed signal; transforming and processing the speed signal to obtain unbalanced angular momentum of each cylinder in the engine, resulting in unbalanced angular momentum fluctuations; and determining whether a misfire has occurred in the corresponding cylinder based on each unbalanced angular momentum. When a misfire occurs in one or more cylinders, the overall engine balance is disrupted, and the speed exhibits periodic fluctuations. The angular momentum fluctuations can be used to determine which cylinder is causing the abnormal work. Using the angular momentum fluctuations as a detection indicator, the method avoids the influence of engine speed, gear position, and load on the detection results, significantly improving detection accuracy.

Description

Technical Field

[0001] The present application relates to the field of vehicle detection technology, and in particular to an engine misfire detection method and device. Background Art

[0002] With the advancement of society, cars have become an essential means of transportation. However, various problems can arise during vehicle operation, including engine misfires. A misfire occurs when one or more cylinders of an engine malfunction. This condition can affect vehicle emissions, potentially failing to meet national OBD standards. It can also cause engine vibration, which in severe cases can impact vehicle safety. Therefore, detecting engine misfires is crucial.

[0003] To address this issue, existing technologies collect engine speed data and determine the acceleration during the power stroke of each cylinder, or the acceleration between two adjacent cylinders, as characteristic values ​​for misfires, thereby determining which cylinder in the engine is misfiring. However, when the engine is operating at low load and a misfire occurs, the engine speed does not change significantly, making it difficult to distinguish whether a misfire has occurred. Furthermore, when the engine speed increases, the speed fluctuations between adjacent cylinders decrease, and when a misfire occurs, the speed acceleration is not noticeable, making it impossible to accurately determine whether an engine misfire has occurred. Therefore, this method of misfire detection is prone to misjudgment and cannot accurately detect engine misfires, which can be dangerous. Summary of the Invention

[0004] In view of this, embodiments of the present application provide an engine misfire detection method and apparatus, which aim to accurately detect engine misfire conditions.

[0005] In a first aspect, an embodiment of the present application provides an engine misfire detection method, the method comprising:

[0006] Collect engine speed signal;

[0007] The speed signal is transformed and processed to obtain unbalanced angular momentum caused by the angular momentum fluctuation imbalance of each cylinder in the engine; the unbalanced angular momentum has a one-to-one correspondence with the cylinder;

[0008] It is determined whether misfire occurs in the corresponding cylinder according to each unbalanced angular momentum.

[0009] Optionally, the transforming and processing the speed signal to obtain the unbalanced angular momentum caused by the unbalanced angular momentum fluctuation of each cylinder in the engine may include:

[0010] Converting the speed signal to obtain an engine angular momentum signal;

[0011] Processing the engine angular momentum signal to obtain imbalance-related component signals in the engine angular momentum fluctuation signal;

[0012] The unbalanced angular momentum of each cylinder causing the angular momentum fluctuation imbalance is obtained according to the imbalance-related component signals.

[0013] Optionally, processing the engine angular momentum signal to obtain each imbalance-related component signal in the engine angular momentum fluctuation signal may include:

[0014] performing anti-aliasing processing on the engine angular momentum signal to obtain a target engine angular momentum signal;

[0015] Perform high-pass filtering on the target engine angular momentum signal to retain the engine angular momentum fluctuation signal;

[0016] performing band-pass filtering on the engine angular momentum fluctuation signal to retain mixed signals of imbalance-related components in the engine angular momentum fluctuation signal;

[0017] The mixed signals of the imbalance-related components are extracted and separated by band-pass filtering to obtain the signals of the imbalance-related components.

[0018] Optionally, obtaining the unbalanced angular momentum of each cylinder caused by the angular momentum fluctuation imbalance according to each imbalance-related component signal may include:

[0019] performing phase compensation on the imbalance-related component signals to obtain target imbalance-related component signals;

[0020] The target imbalance-related component signals are superimposed to obtain the imbalance angular momentum caused by the angular momentum fluctuation imbalance of each cylinder in the engine.

[0021] Optionally, judging whether misfire occurs in the corresponding cylinder according to each unbalanced angular momentum may include:

[0022] When the unbalanced angular momentum is greater than a preset threshold, it is determined that a misfire occurs in the cylinder corresponding to the unbalanced angular momentum.

[0023] In a second aspect, an embodiment of the present application provides an engine misfire detection device, the device comprising:

[0024] An acquisition module is used to acquire the engine speed signal;

[0025] a signal processing module that transforms and processes the speed signal to obtain an unbalanced angular momentum caused by an unbalanced angular momentum fluctuation of each cylinder in the engine; the unbalanced angular momentum has a one-to-one correspondence with the cylinder;

[0026] A judgment module is used to judge whether a misfire occurs in the corresponding cylinder based on each of the unbalanced angular momentums.

[0027] Optionally, the signal processing module may include:

[0028] The first processing unit is used to convert the speed signal into an engine angular momentum signal

[0029] a second processing unit, configured to process the engine angular momentum signal to obtain imbalance-related component signals in the engine angular momentum fluctuation signal;

[0030] The third processing unit is configured to obtain the unbalanced angular momentum of each cylinder causing the angular momentum fluctuation imbalance according to the imbalance-related component signals.

[0031] Optionally, the second processing unit may be specifically configured to:

[0032] performing anti-aliasing processing on the engine angular momentum signal to obtain a target engine angular momentum signal;

[0033] Perform high-pass filtering on the target engine angular momentum signal to retain the engine angular momentum fluctuation signal;

[0034] performing band-pass filtering on the engine angular momentum fluctuation signal to retain mixed signals of imbalance-related components in the engine angular momentum fluctuation signal;

[0035] The mixed signals of the imbalance-related components are extracted and separated by band-pass filtering to obtain the signals of the imbalance-related components.

[0036] Optionally, the third processing unit may be specifically configured to:

[0037] performing phase compensation on the imbalance-related component signals to obtain target imbalance-related component signals;

[0038] The target imbalance-related component signals are superimposed to obtain the imbalance angular momentum caused by the angular momentum fluctuation imbalance of each cylinder in the engine.

[0039] Optionally, the judgment module may be specifically used to:

[0040] When the unbalanced angular momentum is greater than a preset threshold, it is determined that a misfire occurs in the cylinder corresponding to the unbalanced angular momentum.

[0041] This application provides an engine misfire detection method. When executing the method, the speed signal of an engine operating cycle is first acquired in real time. The speed signal is then transformed and processed to obtain the unbalanced angular momentum of each cylinder, which causes the angular momentum fluctuation imbalance. Finally, the misfire is determined in each cylinder based on the unbalanced angular momentum. Using this method, when one or more cylinders misfire, the overall engine balance is disrupted, and the speed exhibits periodic fluctuations. The angular momentum fluctuations can be used to determine which cylinder is causing the abnormal work. Using the angular momentum fluctuations as a detection indicator, the method avoids the influence of speed, gear position, and load on the detection results, significantly improving detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in this embodiment or the prior art, the following briefly introduces the drawings required for use in the embodiment or the prior art description. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 A flow chart of an engine misfire detection method provided in an embodiment of the present application;

[0044] Figure 2 A flowchart of another engine misfire detection method provided in an embodiment of the present application;

[0045] Figure 3 An engine angular momentum signal diagram provided in an embodiment of the present application;

[0046] Figure 4 A target engine angular momentum signal diagram provided in an embodiment of the present application;

[0047] Figure 5 This is a diagram of the engine angular momentum fluctuation signal provided in an embodiment of the present application;

[0048] Figure 6 A mixed signal diagram of unbalanced related components provided in an embodiment of the present application;

[0049] Figure 7 An unbalanced angular momentum diagram of the angular momentum imbalance caused by each cylinder provided in an embodiment of the present application;

[0050] Figure 8 A schematic structural diagram of an engine misfire detection device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0051] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the embodiments described are only part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts are within the scope of protection of this application.

[0052] See also Figure 1 , Figure 1 The flow chart of the engine misfire detection method provided in the embodiment of the present application includes:

[0053] S101: Collecting engine speed signals.

[0054] Specifically, a coaxial signal sensor can be used to collect the original speed signal of one engine working cycle in real time. The engine is analyzed as a whole and the speed signal of one working cycle is processed to improve detection robustness.

[0055] S102: transforming the rotational speed signal to obtain unbalanced angular momentum caused by unbalanced angular momentum fluctuation of each cylinder in the engine.

[0056] Unbalanced angular momentum is used to indicate the fluctuations in the operation of each cylinder in an engine, and there is a one-to-one correspondence between each cylinder and the unbalanced angular momentum. By converting the collected engine speed signal into the unbalanced angular momentum that causes the unbalanced angular momentum fluctuations in each cylinder, the corresponding cylinder can be identified based on the unbalanced angular momentum, as there is a one-to-one correspondence between unbalanced angular momentum and cylinders. By converting the speed signal into unbalanced angular momentum and using angular momentum fluctuation as a detection indicator, the test results are less affected by speed, gear position, and load.

[0057] S103: Determine whether misfire occurs in the corresponding cylinder according to each unbalanced angular momentum.

[0058] In a specific embodiment provided by the present invention, determining whether a misfire occurs in a corresponding cylinder based on each unbalanced angular momentum may include:

[0059] When the unbalanced angular momentum is greater than a preset threshold, it is determined that a misfire occurs in the cylinder corresponding to the unbalanced angular momentum.

[0060] The preset threshold represents the unbalanced angular momentum when the engine is not misfiring. The present embodiment does not specifically limit the method for determining the preset threshold, and the threshold may be determined based on actual circumstances. As an example, the preset threshold may be the maximum value of the unbalanced angular momentum when the engine is operating normally. As another example, the threshold may be calculated and determined by an engineer based on the engine model and vehicle parameters. The unbalanced angular momentum is compared with the preset threshold. If the unbalanced angular momentum is greater than the preset threshold, it indicates that the angular momentum fluctuation imbalance of the corresponding cylinder is beyond the normal range, indicating that the cylinder is in an abnormal operating state, and a misfire is determined in the cylinder.

[0061] This embodiment provides an engine misfire detection method. During execution, the method first acquires a speed signal for one engine operating cycle in real time. Then, the speed signal is transformed and processed to obtain the unbalanced angular momentum of each cylinder, which causes the angular momentum fluctuation imbalance. Finally, the misfire is determined for each cylinder based on the unbalanced angular momentum. Using this method, when one or more cylinders misfire, the overall engine balance is disrupted, and the speed exhibits periodic fluctuations. The angular momentum fluctuations can be used to determine which cylinder is causing the abnormal work. Using the angular momentum fluctuations as a detection indicator eliminates the influence of speed, gear position, and load on the detection results, significantly improving detection accuracy.

[0062] In the embodiment of the present application, the above Figure 1 There are multiple possible implementations of step S102, which are described below. It should be noted that the implementations described below are only for illustrative purposes and do not represent all implementations of the embodiments of the present application.

[0063] See also Figure 2 , Figure 2 A flowchart of another engine misfire detection method provided in an embodiment of the present application.

[0064] S201: Collecting engine speed signals.

[0065] S202: Convert the speed signal to obtain an engine angular momentum signal.

[0066] S203: Processing the engine angular momentum signal to obtain imbalance-related component signals in the engine angular momentum fluctuation signal.

[0067] In one embodiment of the present invention, processing the engine angular momentum signal to obtain each imbalance-related component signal in the engine angular momentum fluctuation signal may include:

[0068] The engine angular momentum signal is subjected to anti-aliasing processing to obtain a target engine angular momentum signal; the target engine angular momentum signal is subjected to high-pass filtering processing to retain an engine angular momentum fluctuation signal; the engine angular momentum fluctuation signal is subjected to band-pass filtering processing to retain mixed signals of various imbalance-related components in the engine angular momentum fluctuation signal; and the mixed signals of various imbalance-related components are extracted and separated by band-pass filtering to obtain the signals of various imbalance-related components.

[0069] See also Figure 3 The signal in the figure is the engine angular momentum signal. By performing anti-aliasing processing on the engine angular momentum signal and reducing the influence of the sampling frequency and interference frequency, we can obtain Figure 4 The target engine angular momentum signal shown in ; then the target engine angular momentum signal is subjected to high-pass filtering, and the low-frequency signal and DC component in the engine angular momentum signal can be filtered out by high-pass filtering, and the engine angular momentum fluctuation signal is retained, and the target engine angular momentum signal is obtained. Figure 5 Finally, the engine angular momentum fluctuation signal is subjected to bandpass filtering to filter out the interference frequency signal in the engine angular momentum fluctuation signal and retain only the unbalanced related component mixed signal in the engine angular momentum fluctuation signal to obtain Figure 6 The unbalanced related component mixed signal shown in , wherein the unbalanced related component mixed signal is a mixed signal of multiple unbalanced related component signals, therefore, the unbalanced related component mixed signal is separated by bandpass filtering to obtain each unbalanced related component signal.

[0070] By performing anti-aliasing processing, high-pass filtering, and band-pass filtering on the engine angular momentum signal, the noise reduction of the engine angular momentum signal is completed, and the imbalance-related component mixed signal in the engine angular momentum fluctuation signal is separated and extracted to obtain each imbalance-related component signal, eliminating the influence of the interference signal on the detection process, reducing errors, and more accurately detecting the working status of the engine and whether there is a misfire, thereby greatly improving the detection accuracy.

[0071] S204: Obtaining the unbalanced angular momentum of each cylinder causing the angular momentum fluctuation imbalance according to the imbalance-related component signals.

[0072] In one embodiment of the present invention, obtaining the unbalanced angular momentum of each cylinder caused by the angular momentum fluctuation imbalance according to each imbalance-related component signal may include:

[0073] Phase compensation is performed on the imbalance-related component signals to obtain target imbalance-related component signals; and the target imbalance-related component signals are superimposed to obtain the imbalance angular momentum caused by the angular momentum fluctuation imbalance of each cylinder in the engine.

[0074] Since the signal after filtering will have phase offset, it is necessary to perform phase compensation on each imbalance-related component signal to eliminate the influence of phase offset on detection accuracy; then the target imbalance-related component signals are superimposed to obtain the unbalanced angular momentum caused by the angular momentum imbalance of each cylinder.

[0075] See also Figure 7 , Figure 7 The unbalanced angular momentum caused by the angular momentum imbalance of each cylinder is shown in . Taking a six-cylinder engine as an example, Figure 7 The horizontal axis represents the crankshaft angle, 0-720° is a working cycle of the engine, and the vertical axis represents the unbalanced angular momentum, where 0-120° corresponds to the operation of cylinder No. 1, 120-240° corresponds to the operation of cylinder No. 2, and so on. 480-600° corresponds to the operation of cylinder No. 5. It can be seen from the figure that at 480-600°, the corresponding unbalanced angular momentum fluctuates significantly, that is, the unbalanced angular momentum corresponding to 480-600° is the unbalanced angular momentum that causes the unbalanced angular momentum of cylinder No. 5 to be unbalanced.

[0076] S205: Determine whether misfire occurs in the corresponding cylinder based on each unbalanced angular momentum.

[0077] In a specific embodiment provided by the present invention, determining whether a misfire occurs in a corresponding cylinder based on each unbalanced angular momentum may include:

[0078] When the unbalanced angular momentum is greater than a preset threshold, it is determined that a misfire occurs in the cylinder corresponding to the unbalanced angular momentum.

[0079] by Figure 7 Taking the unbalanced angular momentum of each cylinder causing angular momentum imbalance as an example, if the preset threshold is 0, the unbalanced angular momentum corresponding to cylinder No. 5 is greater than the preset threshold, indicating that the current angular momentum fluctuation imbalance of cylinder No. 5 exceeds the normal range, and the cylinder is in an abnormal working state, then it is determined that cylinder No. 5 has misfired.

[0080] This embodiment provides an engine misfire detection method. During execution, the method first acquires a speed signal for one engine operating cycle in real time. The speed signal is then transformed and processed to obtain an engine angular momentum signal, which is then processed to obtain various imbalance-related component signals. Unbalance angular momentum is then obtained based on the imbalance-related component signals. Finally, misfire is determined for each cylinder based on the imbalance angular momentum. Using this method, when one or more cylinders misfire, the overall engine balance is disrupted, and the speed exhibits periodic fluctuations. The angular momentum fluctuations can be used to determine which cylinder is causing the abnormal work. Using the angular momentum fluctuations as a detection indicator eliminates the influence of speed, gear position, and load on the detection results, significantly improving detection accuracy.

[0081] The above are some specific implementations of the engine misfire detection method provided in the embodiments of the present application. Based on this, the present application also provides a corresponding device. The device provided in the embodiments of the present application will be introduced from the perspective of functional modularization.

[0082] See also Figure 8 The structure diagram of the engine misfire detection device 200 shown in FIG. 2 includes an acquisition module 210 , a signal processing module 220 and a judgment module 230 .

[0083] The acquisition module 210 is used to acquire the engine speed signal;

[0084] The signal processing module 220 transforms and processes the speed signal to obtain the unbalanced angular momentum of each cylinder in the engine, which causes the angular momentum fluctuation to be unbalanced; the unbalanced angular momentum has a one-to-one correspondence with the cylinder;

[0085] The judgment module 230 is configured to judge whether misfire occurs in the corresponding cylinder based on each unbalanced angular momentum.

[0086] In one embodiment provided in this application, the signal processing module 220 may include:

[0087] a first processing unit, configured to convert the speed signal into an engine angular momentum signal;

[0088] a second processing unit, configured to process the engine angular momentum signal to obtain imbalance-related component signals in the engine angular momentum fluctuation signal;

[0089] The third processing unit is configured to obtain the unbalanced angular momentum of each cylinder causing the angular momentum fluctuation imbalance according to the imbalance-related component signals.

[0090] In one embodiment provided in the present application, the second processing unit may be specifically configured to:

[0091] performing anti-aliasing processing on the engine angular momentum signal to obtain a target engine angular momentum signal;

[0092] Perform high-pass filtering on the target engine angular momentum signal to retain the engine angular momentum fluctuation signal;

[0093] performing band-pass filtering on the engine angular momentum fluctuation signal to retain mixed signals of imbalance-related components in the engine angular momentum fluctuation signal;

[0094] The mixed signals of the imbalance-related components are extracted and separated by band-pass filtering to obtain the signals of the imbalance-related components.

[0095] In one embodiment provided in the present application, the third processing unit may be specifically configured to:

[0096] performing phase compensation on the imbalance-related component signals to obtain target imbalance-related component signals;

[0097] The target imbalance-related component signals are superimposed to obtain the imbalance angular momentum caused by the angular momentum fluctuation imbalance of each cylinder in the engine.

[0098] In one embodiment provided in this application, the determination module 230 may be specifically configured to:

[0099] When the unbalanced angular momentum is greater than a preset threshold, it is determined that a misfire occurs in the cylinder corresponding to the unbalanced angular momentum.

[0100] This embodiment provides an engine misfire detection device that first collects the engine's speed signal over one operating cycle in real time; then, transforms and processes the speed signal to obtain the unbalanced angular momentum of each cylinder, which causes the angular momentum fluctuation imbalance; and finally, determines whether a misfire has occurred in each cylinder based on the unbalanced angular momentum. Through this method, when one or more cylinders misfire, the overall engine balance is disrupted, and the speed exhibits periodic fluctuations. The angular momentum fluctuations can be used to determine which cylinder is causing the abnormal work. Using the angular momentum fluctuations as a detection indicator, the device mitigates the influence of speed, gear position, and load on the detection results, significantly improving detection accuracy.

[0101] The "first" and "second" (if any) in the names mentioned in the embodiments of this application are only used as name identifiers and do not mean the first or second in order.

[0102] Through the description of the above embodiments, it can be known that those skilled in the art can clearly understand that all or part of the steps in the above embodiment methods can be implemented by means of software plus a general hardware platform. Based on this understanding, the technical solution of the present application can be embodied in the form of a software product, which can be stored in a storage medium, such as a read-only memory (ROM) / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network communication device such as a router) to execute the methods described in each embodiment or certain parts of the embodiments of the present application.

[0103] 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 the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple. For the relevant parts, refer to the partial description of the method embodiment. Some or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment. Those of ordinary skill in the art can understand and implement it without paying any creative work.

[0104] The above description is merely an exemplary embodiment of the present application and is not intended to limit the scope of protection of the present application.

Claims

1. An engine misfire detection method, characterized in that: The method comprises: Collect engine speed signal; Converting the speed signal to obtain an engine angular momentum signal; performing anti-aliasing processing on the engine angular momentum signal to obtain a target engine angular momentum signal; Perform high-pass filtering on the target engine angular momentum signal to retain the engine angular momentum fluctuation signal; performing band-pass filtering on the engine angular momentum fluctuation signal to retain mixed signals of imbalance-related components in the engine angular momentum fluctuation signal; Extracting and separating the imbalance-related component mixed signals by bandpass filtering to obtain the imbalance-related component signals; Obtaining the unbalanced angular momentum of each cylinder causing the angular momentum fluctuation imbalance according to the imbalance-related component signals; there is a one-to-one correspondence between the unbalanced angular momentum and the cylinder; It is determined whether misfire occurs in the corresponding cylinder according to each unbalanced angular momentum.

2. The method according to claim 1, characterized in that The step of obtaining the unbalanced angular momentum of each cylinder caused by the angular momentum fluctuation imbalance according to each imbalance-related component signal includes: performing phase compensation on the imbalance-related component signals to obtain target imbalance-related component signals; The target imbalance-related component signals are superimposed to obtain the imbalance angular momentum caused by the angular momentum fluctuation imbalance of each cylinder in the engine.

3. The method according to claim 1, characterized in that The determining whether misfire occurs in the corresponding cylinder according to each unbalanced angular momentum includes: When the unbalanced angular momentum is greater than a preset threshold, it is determined that a misfire occurs in the cylinder corresponding to the unbalanced angular momentum.

4. An engine misfire device, characterized in that: The device comprises: An acquisition module is used to acquire the engine speed signal; Signal processing module, including: The first processing unit is used to convert the speed signal into an engine angular momentum signal a second processing unit, configured to perform anti-aliasing processing on the engine angular momentum signal to obtain a target engine angular momentum signal; perform high-pass filtering on the target engine angular momentum signal to retain an engine angular momentum fluctuation signal; perform band-pass filtering on the engine angular momentum fluctuation signal to retain mixed signals of imbalance-related components in the engine angular momentum fluctuation signal; and extract and separate the mixed signals of the imbalance-related components through band-pass filtering to obtain the imbalance-related component signals; a third processing unit, configured to obtain the unbalanced angular momentum of each cylinder causing the angular momentum fluctuation imbalance according to each imbalance-related component signal; A judgment module is used to judge whether a misfire occurs in the corresponding cylinder based on each of the unbalanced angular momentums.

5. The device according to claim 4, characterized in that The third processing unit is specifically configured to: performing phase compensation on the imbalance-related component signals to obtain target imbalance-related component signals; The target imbalance-related component signals are superimposed to obtain the imbalance angular momentum caused by the angular momentum fluctuation imbalance of each cylinder in the engine.

6. The device according to claim 4, characterized in that The judgment module is specifically used for: When the unbalanced angular momentum is greater than a preset threshold, it is determined that a misfire occurs in the cylinder corresponding to the unbalanced angular momentum.

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