Knock signal credibility detection method and system, engine and motor vehicle

Abstract

The invention relates to a knock signal credibility detection method and system, an engine and a motor vehicle, and the method comprises the steps: obtaining a signal of a knock sensor, extracting a background noise signal of a combustion window, and a signal corresponding to a set range in front of a cylinder compression top dead center in the non-combustion window in a continuous non-combustion window period and a combustion window period, and recording the signals as Pre window signals; a Pre window signal is credible, and when consistency calibration is carried out, if a difference value between a background noise signal of a current cylinder combustion window and a weighted value of background noise of other cylinder combustion windows exceeds a set threshold value, a signal obtained by a knock sensor in the combustion window drifts; when consistency calibration is not carried out, if the difference value between the background noise signal of the combustion window of the current cylinder and the signal of the Pre window exceeds a set threshold value, the signal obtained by the knock sensor in the combustion window drifts, and when the drifting frequency exceeds the limit, the corresponding knock judgment result is incredible. The signals of the non-combustion window and the signals of the plurality of knock sensors are used for mutual verification.

Description

Technical Field

[0001] The present invention relates to the technical field of engine control, and specifically to a method and system for detecting the credibility of knock signals, an engine, and a motor vehicle. Background Art

[0002] The statements in this part only provide background technical information related to the present invention, and do not necessarily constitute prior art.

[0003] The knock sensor monitors the vibration signal during engine operation to identify the knock phenomenon. If the occurrence of knock combustion is identified, ignition will be adjusted to avoid continuous knock combustion, such as measures like fuel cut-off, mixture enrichment, throttle restriction, etc. to protect the engine.

[0004] The knock sensor collects voltage signals in the combustion window corresponding to the cylinder, and determines whether knock occurs by processing the signals. At the same time, the diagnosis of the knock sensor is also carried out within this window. Therefore, the determination and diagnosis of the knock signal depend on the signal situation in the combustion window. If, in some cases, the signal obtained by the knock sensor in the combustion window is interfered with, it will affect the determination of knock. Summary of the Invention

[0005] In order to solve the technical problems existing in the above background art, the present invention provides a method and system for detecting the credibility of knock signals, an engine, and a motor vehicle. By using the signals in the non-combustion window and cross-checking the signals of multiple knock sensors, it assists in judging the quality of the knock signal and performs corresponding degradation when a problem is determined.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The first aspect of the present invention provides a method for detecting the credibility of knock signals, including the following steps:

[0008] During continuous non-combustion windows and combustion windows, obtain the signals of the knock sensor, extract the background noise signal of the combustion window, and the signals corresponding to the set range before the top dead center of cylinder compression in the non-combustion window, denoted as the Pre-window signal;

[0009] If the Pre-window signal is credible and after consistency calibration, if the difference between the background noise signal of the current cylinder's combustion window and the weighted value of the background noise of other cylinders' combustion windows exceeds the set threshold, then the signal obtained by the knock sensor in the combustion window drifts;

[0010] If the Pre-window signal is credible but has not undergone consistency calibration, if the difference between the background noise signal of the current cylinder's combustion window and the Pre-window signal exceeds the set threshold, then the signal obtained by the knock sensor in the combustion window drifts;

[0011] When the number of times that the signal obtained by the knock sensor drifts during the combustion window exceeds the limit, the corresponding knock determination result is not credible, and the ignition advance angle is corrected.

[0012] Furthermore, the ignition advance angle is corrected as follows: the knock retard angle is used to correct the ignition advance angle, and the knock retard angle = correction coefficient x * average value of the knock retard angles of other cylinders + correction coefficient y * maximum value of the knock retard angles of other cylinders.

[0013] Furthermore, when the Pre window signal is not credible, the ignition advance angle is corrected.

[0014] Furthermore, if the deviation between the obtained Pre window signal and the preset value does not exceed the set value, the Pre window signal is credible; if the deviation exceeds the set value, the Pre window signal is not credible.

[0015] Furthermore, when the Pre window signal is credible and the engine has passed the consistency calibration, if the difference between the background noise signal of the current cylinder combustion window and the weighted value of the Pre window signals of other cylinders exceeds the set threshold, the signal obtained by the knock sensor drifts during the combustion window.

[0016] Furthermore, the combustion window is the time period from the ignition of the spark plug to the end of combustion in the cylinder. During this time period, the crankshaft rotates from x° to y°.

[0017] Furthermore, the non-combustion window is the set range before the top dead center of cylinder compression, and the corresponding crankshaft angle range is z° - x°, where the crankshaft reaches x° corresponding to the top dead center of cylinder compression.

[0018] The second aspect of the present invention provides a knock signal credibility detection system, including:

[0019] A signal acquisition unit, configured to: during continuous non-combustion windows and combustion windows, acquire the signal of the knock sensor, extract the background noise signal of the combustion window, and the signal corresponding to the set range before the top dead center of cylinder compression in the non-combustion window, denoted as the Pre window signal;

[0020] A knock signal credibility detection unit, configured to: when the Pre window signal is credible and after passing the consistency calibration, if the difference between the background noise signal of the current cylinder combustion window and the weighted value of the background noises of other cylinder combustion windows exceeds the set threshold, the signal obtained by the knock sensor drifts during the combustion window;

[0021] The knock signal credibility detection unit is further configured to: when the Pre window signal is credible but has not passed the consistency calibration, if the difference between the background noise signal of the current cylinder combustion window and the Pre window signal exceeds the set threshold, the signal obtained by the knock sensor drifts during the combustion window;

[0022] A correction unit is configured to correct the ignition advance angle when the number of times of signal drift of the knock sensor during the combustion window exceeds the limit and the corresponding knock determination result is untrustworthy.

[0023] The third aspect of the present invention provides an engine equipped with a controller, and the controller executes the steps in the above-mentioned knock signal credibility detection method.

[0024] The fourth aspect of the present invention provides a motor vehicle having an in-vehicle computer, and the in-vehicle computer executes the steps in the above-mentioned knock signal credibility detection method.

[0025] Compared with the prior art, the above one or more technical solutions have the following beneficial effects:

[0026] In the traditional signal processing method, the signal obtained by the knock sensor during the combustion window period is used as the basis for judging the occurrence of knock. When the signal obtained by the knock sensor during the combustion window is interfered, it will affect the determination of knock. However, in this solution, the signal during the non-combustion window and the mutual verification of the signals of multiple knock sensors are used instead of the signal during the combustion window period to assist in judging the quality of the knock signal. When it is determined that the signal obtained by the knock sensor during the combustion window period drifts, it is considered that the signal is interfered, and at this time the knock determination result is untrustworthy. By correcting the ignition advance angle, the corresponding downgrade control is realized, which can better protect the engine from knock when the signal of the knock sensor is interfered and misjudgment may occur. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0028] Figure 1 It is a schematic diagram of the knock signal credibility detection process provided by one or more embodiments of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0030] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0032] Term Explanation:

[0033] Knock: It refers to the process in which the local mixture in the engine cylinder undergoes self-ignition before the normal flame front arrives, and there are two or more (including two) flame fronts (ignition + self-ignition) acting violently in the cylinder, causing impacts on the cylinder wall, piston, etc.

[0034] Combustion window refers to the time period during which the combustion process occurs in a certain cylinder during the engine working cycle. Specifically, it refers to the time period from the ignition of the spark plug to the end of combustion.

[0035] The process of the knock sensor obtaining signals within the combustion window and realizing knock detection and judgment is a complex mechanism that combines mechanical vibration detection, signal processing, and real-time control. The combustion window is the time period from the ignition of the spark plug to the end of combustion of a certain cylinder (usually from a few milliseconds to dozens of milliseconds), and knock usually occurs in the middle and late stages of combustion (i.e., about 10 - 30° crankshaft angle after ignition), at which time abnormal superposition of in-cylinder pressure waves is likely to cause knock.

[0036] When the engine generates high-frequency vibrations (frequency range is usually 5 - 20 kHz) due to knock, the knock sensor generates a signal (electrical signal or magnetic signal) proportional to the vibration intensity. The ECU performs band-pass filtering on the signal output by the sensor, only retaining the knock characteristic frequency range (such as 5 - 15 kHz), filtering out other mechanical noises of the engine (such as low-frequency vibrations of valve opening and closing, piston movement, etc.), and then through processes such as threshold comparison, frequency analysis, and duration determination, it is determined that knock has occurred in this cylinder. The ECU then issues corresponding instructions according to the current working condition of the engine to suppress knock and avoid mechanical damage to the engine, such as retarding the ignition timing, adjusting the air-fuel ratio, turbocharging control, etc.

[0037] As introduced in the background technology, the knock sensor collects voltage signals in the combustion window of the corresponding cylinder to determine whether knock occurs, and the diagnosis of the knock sensor is also carried out within this window. Therefore, the determination and diagnosis of the knock signal depend on the signal situation of the combustion window. If in some cases, the signal obtained by the knock sensor in the combustion window is interfered with, it cannot be determined whether the signal obtained by the knock sensor at this time is reliable, which will affect the determination of knock.

[0038] Therefore, the following embodiments provide a method and system for detecting the credibility of knock signals, an engine, and a motor vehicle. By using signals in the non-combustion window and cross-checking multiple knock sensor signals, it assists in determining the quality of knock signals and performs corresponding degradation when problems are detected.

[0039] Embodiment 1:

[0040] In the prior art, the signal obtained by the knock sensor during the combustion window is used as the basis for determining whether knock occurs. In this embodiment, in addition to considering the combustion window, the non-combustion window period before the combustion window is also considered, and the Pre-window signal is obtained. Here, the Pre-window signal refers to the signal obtained by the knock sensor within a set range before the top dead center (TDC) of cylinder compression.

[0041] The combustion window is the time period from the ignition of the spark plug to the end of combustion in the cylinder. This time period corresponds to the rotation angle of the crankshaft, that is, when the crankshaft rotates from x° to y°, the cylinder goes from the ignition of the spark plug to the end of combustion.

[0042] The top dead center (TDC) of cylinder compression is the highest point reached by the piston during the compression stroke. At this time, the cylinder volume is the smallest and the pressure is the largest. The ignition time of the spark plug is usually close to TDC, but not necessarily at TDC. The choice of ignition time depends on the engine design and operating conditions, with the aim of igniting the air-fuel mixture at the optimal time to achieve efficient combustion. Therefore, the ignition time may be before TDC (advanced ignition) or after TDC (retarded ignition), which is specifically adjusted by the engine control unit (ECU) according to factors such as engine speed and load.

[0043] The Pre-window signal obtained in this embodiment refers to the signal obtained by the knock sensor within a set range before the top dead center of cylinder compression. Here, the set range can be expressed as the angle range rotated by the crankshaft. For example, assuming that the "top dead center of cylinder compression" is 0°, the combustion window is 0° - a°, and the non-combustion window is b° - 0°, where a is a positive value and b is a negative value.

[0044] The main implementation process of this embodiment is as follows:

[0045] When the deviation between the current Pre-window signal and the bench preset value is within a certain range, the Pre-window signal is considered credible.

[0046] If the knock signal consistency of each cylinder has been ensured to be relatively good through calibration means or strategy means in the early stage, the background noise signal of the current cylinder's combustion window can be compared with the weighted value of the background noise of other cylinders' combustion windows, or the background noise signal of the current cylinder's combustion window can be compared with the weighted value of other cylinders' Pre-window signals. When any of these comparison methods exceeds the limit, it is considered that the knock signal in the combustion window has drifted.

[0047] When it is determined that knocking occurs in the prior art, the ignition advance angle will be corrected. Since the knocking signal is not credible and the knocking determination situation of the current cylinder is also not credible, in the problem working condition, the ignition advance angle calculated by the problem cylinder will no longer be used for correction, but the knocking retard angle of other cylinders without problems will be used as the correction for the problem cylinder. The knocking retard angle is the average value of the knocking retard angles of other cylinders multiplied by the correction coefficient x plus the maximum value of the knocking retard angles of other cylinders multiplied by the correction coefficient y, and the correction coefficients can be calibrated.

[0048] If the knocking signal consistency of each cylinder cannot be ensured by calibration means or strategy means in the early stage, only the comparison between the background noise signal of the current cylinder combustion window and the Pre window signal will be carried out. When the problem working condition and the problem cylinder are determined, the same downgrading operation as above will be performed.

[0049] A method for detecting the credibility of a knocking signal, comprising the following steps:

[0050] During continuous non-combustion windows and combustion windows, obtain the signal of the knocking sensor, extract the background noise signal of the combustion window, and the signal corresponding to the set range before the top dead center of cylinder compression in the non-combustion window, denoted as the Pre window signal;

[0051] When the Pre window signal is credible and has passed the consistency calibration, if the difference between the background noise signal of the current cylinder combustion window and the weighted value of the background noise of other cylinder combustion windows exceeds the set threshold, the signal obtained by the knocking sensor in the combustion window drifts;

[0052] When the Pre window signal is credible but has not passed the consistency calibration, if the difference between the background noise signal of the current cylinder combustion window and the Pre window signal exceeds the set threshold, the signal obtained by the knocking sensor in the combustion window drifts;

[0053] When the number of times that the signal obtained by the knocking sensor in the combustion window drifts exceeds the limit, the corresponding knocking determination result is not credible, and the ignition advance angle is corrected.

[0054] As a further implementation manner, the ignition advance angle is corrected specifically as follows: the ignition advance angle is corrected using the knocking retard angle, and the knocking retard angle = the average value of the knocking retard angles of other cylinders multiplied by the correction coefficient x plus the maximum value of the knocking retard angles of other cylinders multiplied by the correction coefficient y.

[0055] As a further implementation manner, when the Pre window signal is not credible, the ignition advance angle is corrected.

[0056] As a further implementation manner, if the deviation between the obtained Pre window signal and the preset value does not exceed the set value, the Pre window signal is credible; if the deviation exceeds the set value, the Pre window signal is not credible.

[0057] As a further implementation, the Pre-window signal is reliable, and when the engine has passed the consistency calibration, the difference between the background noise signal of the current cylinder's combustion window and the weighted value of the Pre-window signals of other cylinders exceeds the set threshold, and the signal obtained by the knock sensor during the combustion window drifts.

[0058] Specifically, as Figure 1 shown: When |Current Pre-window signal - Bench preset value| < Threshold 1, the Pre-window signal is reliable; if it is not less than Threshold 1, the Pre-window signal is considered unreliable.

[0059] When the Pre-window signal is reliable, it is judged whether the engine has passed the consistency calibration. Specifically:

[0060] If the signals of each cylinder have been calibrated for consistency during the calibration phase, or the consistency correction strategy has been started, and |Background noise signal of the current cylinder's combustion window - fac1 * Weighted value of the Pre-window signals of each cylinder| > Threshold 2, or |Background noise signal of the current cylinder's combustion window - fac2 * Weighted value of the background noise of each cylinder's combustion window| > Threshold 3, then the knock signal in the combustion window drifts; if any of the above judgments does not exceed the corresponding threshold, then the knock signal in the combustion window does not drift.

[0061] If the signals of each cylinder have not been calibrated for consistency during the calibration phase, or the consistency correction strategy has not been started, but |Background noise signal of the current cylinder's combustion window - Current cylinder's Pre-window signal| > Threshold 4, then the knock signal in the combustion window drifts.

[0062] When the knock signal in the combustion window drifts, count the number of times exceeding the threshold under each working condition of the current cylinder. If the counted number exceeds the limit, then there is a problem with the background noise signal of the current cylinder under the corresponding working condition, and the corresponding knock determination result is unreliable; if the Pre-window signal is unreliable, the corresponding knock determination result is also considered unreliable.

[0063] Therefore, for the cylinders with problems, instead of using the ignition advance angle for correction, the knock retard angle of other cylinders without problems is used as the correction for the problem cylinder. Knock retard angle = fac4 * Average value of the knock retard angles of other cylinders + fac5 * Maximum value of the knock retard angles of other cylinders.

[0064] If the counted number does not exceed the limit, return for re-judgment.

[0065] In this embodiment, fac1 - fac5 are all correction coefficients (i.e., weighting coefficients). Among them, fac4 corresponds to the correction coefficient x, and fac5 corresponds to the correction coefficient y. All correction coefficients can be calibrated through experiments, simulations, or other similar methods.

[0066] In the traditional signal processing method, the signal obtained by the knock sensor during the combustion window period is used as the basis for judging the occurrence of knock. When the signal obtained by the knock sensor during the combustion window is interfered with, it will affect the judgment of knock. However, this solution does not use the signal during the combustion window period, but uses the signal during the non-combustion window and the mutual verification of the signals of multiple knock sensors to assist in judging the quality of the knock signal. When it is judged that the signal obtained by the knock sensor during the combustion window period drifts, it is considered that the signal is interfered with, and at this time, the knock judgment result is not credible. By correcting the ignition advance angle, the corresponding downgrade control is realized, which can better protect the engine from knock when the signal of the knock sensor is interfered with and misjudgment may occur.

[0067] Embodiment 2:

[0068] The second aspect of the present invention provides a knock signal credibility detection system, including:

[0069] A signal acquisition unit, configured to: during continuous non-combustion window and combustion window periods, acquire the signal of the knock sensor, extract the background noise signal of the combustion window, and the signal corresponding to the set range before the top dead center of cylinder compression during the non-combustion window, denoted as the Pre-window signal;

[0070] A knock signal credibility detection unit, configured to: when the Pre-window signal is credible and after consistency calibration, if the difference between the background noise signal of the current cylinder combustion window and the weighted value of the background noise of other cylinder combustion windows exceeds the set threshold, then the signal obtained by the knock sensor during the combustion window drifts;

[0071] The knock signal credibility detection unit is further configured to: when the Pre-window signal is credible but has not undergone consistency calibration, if the difference between the background noise signal of the current cylinder combustion window and the Pre-window signal exceeds the set threshold, then the signal obtained by the knock sensor during the combustion window drifts;

[0072] A correction unit, configured to: when the number of times that the signal obtained by the knock sensor during the combustion window drifts exceeds the limit, the corresponding knock judgment result is not credible, and correct the ignition advance angle.

[0073] In the traditional signal processing method, the signal obtained by the knock sensor during the combustion window period is used as the basis for judging the occurrence of knocking. When the signal obtained by the knock sensor during the combustion window is interfered with, it will affect the judgment of knocking. In this solution, instead of using the signal during the combustion window, the signals during the non-combustion window and the signals of multiple knock sensors are used to mutually verify each other to assist in judging the quality of the knock signal. When it is judged that the signal obtained by the knock sensor during the combustion window period drifts, it is considered that the signal is interfered with, and at this time, the knocking judgment result is not credible. By correcting the ignition advance angle, the corresponding downgrade control is achieved, which can better protect the engine from knocking when the signal of the knock sensor is interfered with and misjudgment may occur.

[0074] Embodiment 3:

[0075] An engine is equipped with a controller, and the controller executes the steps in the above-mentioned knock signal credibility detection method.

[0076] The controller does not limit the specific structural form, can call the signal obtained by the knock sensor and process the corresponding signals during the combustion window and the non-combustion window, and issue corresponding instructions to the engine.

[0077] In the traditional signal processing method, the signal obtained by the knock sensor during the combustion window period is used as the basis for judging the occurrence of knocking. When the signal obtained by the knock sensor during the combustion window is interfered with, it will affect the judgment of knocking. In this solution, instead of using the signal during the combustion window, the signals during the non-combustion window and the signals of multiple knock sensors are used to mutually verify each other to assist in judging the quality of the knock signal. When it is judged that the signal obtained by the knock sensor during the combustion window period drifts, it is considered that the signal is interfered with, and at this time, the knocking judgment result is not credible. By correcting the ignition advance angle, the corresponding downgrade control is achieved, which can better protect the engine from knocking when the signal of the knock sensor is interfered with and misjudgment may occur.

[0078] Embodiment 4:

[0079] A motor vehicle has an on-vehicle computer, and the on-vehicle computer executes the steps in the above-mentioned knock signal credibility detection method.

[0080] In the traditional signal processing method, the signal obtained by the knock sensor during the combustion window period is used as the basis for judging the occurrence of knock. When the signal obtained by the knock sensor during the combustion window is interfered with, it will affect the judgment of knock. However, this solution does not use the signal during the combustion window period, but uses the signal outside the combustion window and the mutual verification of the signals of multiple knock sensors to assist in judging the quality of the knock signal. When it is judged that the signal obtained by the knock sensor during the combustion window period drifts, it is considered that the signal is interfered with, and at this time, the knock judgment result is not credible. By correcting the ignition advance angle, the corresponding downgrade control is realized, which can better protect the engine from knock when the signal of the knock sensor is interfered with and misjudgment may occur.

[0081] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A knock signal credibility detection method, characterized in that: The following steps are involved: During the continuous non-combustion window and combustion window, the signal of the knock sensor is obtained, the background noise signal of the combustion window is extracted, and the signal corresponding to the set range before the cylinder compression top dead center in the non-combustion window is recorded as the Pre window signal; The Pre window signal is credible and, after consistency calibration, if the difference between the background noise signal of the current cylinder combustion window and the weighted value of the background noise of other cylinder combustion windows exceeds the set threshold, the signal obtained by the knock sensor in the combustion window drifts; The Pre window signal is credible, but has not been calibrated for consistency. If the difference between the background noise signal of the current cylinder combustion window and the Pre window signal exceeds the set threshold, the signal obtained by the knock sensor in the combustion window will drift; The number of times the signal obtained by the knock sensor in the combustion window drifts exceeds the limit, the corresponding knock determination result is unreliable, and the ignition advance angle is corrected.

2. The knock signal credibility detection method according to claim 1, characterized in that: The ignition advance angle is corrected, specifically: the ignition advance angle is corrected using the knock recession angle, where the knock recession angle = correction coefficient x*average value of the knock recession angles of other cylinders+correction coefficient y*maximum value of the knock recession angles of other cylinders.

3. The knock signal credibility detection method according to claim 1, characterized in that: When the Pre window signal is unreliable, the ignition advance angle is corrected.

4. The knock signal credibility detection method according to claim 1, characterized in that: If the deviation between the obtained Pre window signal and the preset value does not exceed the set value, the Pre window signal is credible; if the deviation exceeds the set value, the Pre window signal is unreliable.

5. The knock signal credibility detection method according to claim 1, characterized in that: When the Pre window signal is credible and the engine has been calibrated for consistency, the difference between the background noise signal of the current cylinder combustion window and the weighted value of the Pre window signal of other cylinders exceeds the set threshold, and the signal obtained by the knock sensor in the combustion window drifts.

6. The knock signal credibility detection method according to claim 1, characterized in that: The combustion window is the time period from the ignition of the spark plug to the end of combustion in the cylinder. During this time period, the crankshaft rotates from x° to y°.

7. The knock signal credibility detection method according to claim 1, characterized in that: The non-combustion window is a set range before the compression top dead center of the cylinder, and the corresponding crankshaft angle range is z°-x°, where the crankshaft rotates to x° corresponding to the compression top dead center of the cylinder.

8. A knock signal credibility detection system, characterized in that: include: A signal acquisition unit is connected to the knock sensor and is used to obtain the signal of the knock sensor during the continuous non-combustion window and the combustion window, and extract the background noise signal of the combustion window and the signal corresponding to the set range before the cylinder compression top dead center in the non-combustion window, which is recorded as the Pre window signal; The knock signal credibility detection unit is configured as follows: if the Pre window signal is credible and after consistency calibration, if the difference between the background noise signal of the current cylinder combustion window and the weighted value of the background noise of other cylinder combustion windows exceeds a set threshold, then the signal obtained by the knock sensor in the combustion window drifts; The knock signal credibility detection unit is further configured as follows: when the Pre window signal is credible but has not been calibrated for consistency, if the difference between the background noise signal of the combustion window of the current cylinder and the Pre window signal exceeds a set threshold, the signal obtained by the knock sensor in the combustion window drifts; The correction unit is configured to correct the ignition advance angle when the number of times the signal obtained by the knock sensor in the combustion window drifts exceeds a limit and the corresponding knock determination result is unreliable.

9. An engine, characterized in that: A controller is provided, which executes the steps in the knock signal credibility detection method as described in any one of claims 1-7.

10. A motor vehicle, characterized in that: A vehicle-mounted computer is provided, and the vehicle-mounted computer executes the steps in the knock signal credibility detection method as described in any one of claims 1-7.

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