Knock detection device

Abstract

To provide a technology for accurately detecting knocking of an internal combustion engine by minimizing influence of vibration which is generated during driving of an injector.SOLUTION: A knocking detection device 20 comprises a data acquisition unit 24, a vibration data unit 26, a noise data unit 28, a correction unit 30 and a knocking determination unit 32. The vibration data unit creates vibration data indicating a vibration level of a frequency component chronologically on the basis of detection data acquired by the data acquisition unit. The noise data unit creates noise data indicating the vibration level of the frequency component chronologically on the basis of detection data which are acquired when an injector is driven. The correction unit creates corrected vibration data by correcting the vibration data using the noise data on the basis of detection data which are acquired in a determination section. The knocking determination unit determines whether or not knocking has occurred on the basis of the corrected vibration data.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a technique for detecting knocking in an internal combustion engine. [Background technology]

[0002] A technique for detecting knocking in an internal combustion engine based on detection data from a knock sensor that detects vibrations in the internal combustion engine is known. When knocking is detected, control such as retarding the ignition timing is performed to suppress the knocking.

[0003] However, if vibrations other than knocking are mixed into the detection data as noise, it may be erroneously determined that knocking has occurred when it has not.If a control such as retarding the ignition timing is performed due to the erroneous determination that knocking has occurred, there is a risk that fuel economy and the torque generated by the internal combustion engine will decrease.

[0004] Furthermore, if a vibration other than knocking occurs as noise when knocking occurs, it may not be possible to detect the occurrence of knocking. If the occurrence of knocking is left undetected, it may result in increased noise due to abnormal combustion or damage to the internal combustion engine.

[0005] Therefore, the technology described in Patent Document 1 attempts to remove, as noise, vibrations that occur when the intake valve opens and closes from the vibrations of the internal combustion engine detected by the knock sensor. In the technology described in Patent Document 1, frequency component analysis is performed on detection data from a knock sensor, and a two-dimensional map of crank angle and frequency is generated as a detection intensity map. Furthermore, for noise generated when the intake valve opens and closes, frequency component analysis is performed on detection data from the knock sensor when it is determined that knocking is not occurring, and a two-dimensional map of crank angle and frequency is generated as a noise component intensity map.

[0006] The technology described in Patent Document 1 attempts to detect knocking based on a binarized noise correction map obtained by subtracting a noise component intensity map from a detection intensity map, using a predetermined threshold value. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2017-190766 Summary of the Invention [Problem to be solved by the invention]

[0008] However, after detailed investigation by the inventors, it was found that the technology described in Patent Document 1 takes into account the vibrations that occur when the intake valve opens and closes, but does not take into account the vibrations that occur when the injector is driven to open and close.

[0009] The vibrations generated when the intake valve opens and closes become smaller as the engine speed decreases. However, the magnitude of the vibrations generated when the injector is driven hardly changes depending on the engine speed. Therefore, the lower the engine speed, the greater the proportion of the vibrations generated when the injector is driven relative to the engine vibrations detected by the knock sensor.

[0010] Furthermore, as the pressure of fuel injected by the injector increases, the vibrations generated when the injector is driven increase. Furthermore, due to the multi-stage fuel injection, vibrations that occur when the injector injects fuel during the compression stroke of the cylinder may overlap with the period during which knocking is determined in another cylinder.

[0011] Therefore, there is a need to detect the vibrations that occur when the injector is driven. One aspect of the present disclosure is to provide a technique for detecting knocking in an internal combustion engine with high accuracy by eliminating as much as possible the influence of vibrations that occur when an injector is driven. [Means for solving the problem]

[0012] A knocking detection device according to one aspect of the present disclosure detects knocking in an internal combustion engine (10) in which fuel is directly injected into cylinders from injectors (12) installed in the cylinders, and includes a data acquisition unit (24, S400, S420), a vibration data unit (26, S402), a noise data unit (28, S422 to S428), a correction unit (30, S406), and a knocking determination unit (32, S410).

[0013] The data acquisition unit acquires detection data from a knock sensor (16) that detects vibrations of the internal combustion engine. The vibration data unit performs frequency component analysis on the detection data acquired by the data acquisition unit, and generates vibration data that represents the vibration levels of the frequency components in a time series.

[0014] The noise data unit performs frequency component analysis on the detection data acquired by the data acquisition unit when the injector is driven, and generates noise data that time-series represents the vibration levels of the frequency components when the injector is driven. The correction unit corrects, based on the noise data, the vibration data generated by the vibration data unit based on the detection data acquired by the data acquisition unit in a determination section for determining whether knocking has occurred. The knocking determination unit determines whether knocking has occurred based on the corrected vibration data generated by the correction unit.

[0015] According to this configuration, vibration data obtained by frequency component analysis of detection data from the knock sensor detected in a determination section in which it is determined whether knocking has occurred is corrected with noise data obtained by frequency component analysis of detection data when the injector is driven.

[0016] This makes it possible to remove noise that occurs when the injector is driven from the vibration data generated in the determination section where it is determined whether knocking has occurred, thereby enabling knocking in an internal combustion engine to be detected with high accuracy. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a block diagram showing the configuration of a knocking detection device according to an embodiment of the present invention; [Figure 2] 1 is a schematic diagram showing the stroke of each cylinder of an internal combustion engine. [Figure 3] 10 is a time chart showing the difference in vibration depending on whether or not injector noise is present. [Figure 4] 4 is a flowchart showing a knocking detection process. [Figure 5] FIG. 4 is an explanatory diagram illustrating removal of injector noise. [Figure 6] FIG. 4 is an explanatory diagram illustrating knocking detection using determination reference data. [Figure 7] FIG. 10 is an explanatory diagram showing determination criteria data according to frequency ranges. [Figure 8] 10 is another flowchart showing the knocking detection process. [Figure 9] FIG. 10 is an explanatory diagram illustrating generation of determination criterion data. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. [1. Configuration] 1 is mounted on a vehicle and detects knocking that occurs in an internal combustion engine 10. Hereinafter, the internal combustion engine will also be referred to as an engine. A crank angle, which represents the rotational angle position of a crankshaft 2 that drives the engine 10, is detected by an angle sensor (not shown).

[0019] The engine 10 is, for example, a direct injection engine in which fuel is directly injected into each of four cylinders from an injector 12 installed in each cylinder. The fuel injected into the cylinders is ignited by a spark plug 14.

[0020] The knock sensor 16 is installed, for example, near the center of the four cylinders arranged in a row, and detects vibrations of the engine 10 and outputs detection data. The knocking detection device 20 is a well-known microcomputer including a CPU, ROM, RAM, and bus lines connecting these components (not shown). By executing a program stored in the ROM, the knocking detection device 20 functions as a combustion control unit 22, a data acquisition unit 24, a vibration data unit 26, a noise data unit 28, a correction unit 30, and a knock determination unit 32.

[0021] The combustion control unit 22 controls the opening and closing timing of the injector 12 based on the crank angle, thereby controlling the injection amount and injection timing of the injector 12. Furthermore, the combustion control unit 22 controls the ignition timing of the spark plug 14 based on the crank angle, thereby controlling the combustion timing of the fuel. The data acquisition unit 24 acquires detection data from the knock sensor 16.

[0022] The vibration data unit 26 performs frequency component analysis on the detection data acquired from the knock sensor 16 by the data acquisition unit 24 in a determination section described later, and generates vibration data that represents the vibration levels of the frequency components in a time series.

[0023] First, the vibration data unit 26 generates a two-dimensional map of frequency and time, which represents the relationship between time and the vibration level of each frequency component as vibration data representing the vibration level of each frequency component in a time series. In the two-dimensional map, the vibration level of each frequency component is represented on coordinates defined by time and frequency.

[0024] Furthermore, the vibration data unit 26 converts time into crank angle based on the rotation speed of the engine 10, thereby generating a two-dimensional map of frequency and crank angle as vibration data.

[0025] The noise data unit 28 performs frequency component analysis on the detection data acquired by the data acquisition unit 24 when the injector 12 is driven and opened / closed during the intake stroke of each cylinder, which is a section where knocking does not occur, for each injector 12 of each cylinder. As a result of the analysis, the noise data unit 28 generates noise data for each injector 12 of each cylinder, which represents, in time series, the vibration levels of frequency components when the injector 12 is driven.

[0026] The noise data unit 28 generates, as noise data, a two-dimensional map of frequency and time that shows the relationship between time and the vibration level of each frequency component, similar to the vibration data. In the two-dimensional map, the vibration level of each frequency component is represented on coordinates defined by time and frequency, similar to the vibration data.

[0027] Furthermore, the noise data unit 28 converts time into crank angle based on the rotation speed of the engine 10, thereby generating a two-dimensional map of frequency and crank angle as noise data.

[0028] For a cylinder subject to knocking detection, the correction unit 30 subtracts and removes noise data generated when the injector 12 is driven during a stroke of another cylinder that overlaps with the vibration data of the determination section of the combustion stroke. In this way, the correction unit 30 removes injector noise, which is vibration noise generated when the injector 12 is driven, from the vibration of the engine 10 detected by the knock sensor 16, to generate corrected vibration data.

[0029] The knocking determination unit 32 determines whether or not knocking has occurred in the engine 10 based on the corrected vibration data generated by the correction unit 30. [1-2. Operation of Engine 10] As shown in FIG. 2, each cylinder of the four-cylinder engine 10 executes an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke such that the same strokes do not overlap with each other.

[0030] In the direct injection engine 10, it is desirable to improve fuel economy and emissions by increasing fuel pressure and using multi-stage injection. In the multi-stage injection of this embodiment, fuel is injected in multiple stages during both the intake stroke and the compression stroke of each cylinder. The fuel injected in multiple stages during the intake stroke and the compression stroke is ignited by the spark plug 14 during the combustion stroke.

[0031] Knocking of the engine 10 occurs when fuel injected from the injector 12 is ignited at a timing other than the predetermined timing by the spark plug 14, resulting in abnormal combustion.

[0032] 2, in the knocking determination section indicated by diagonal lines in the combustion stroke of each cylinder, it is determined whether or not knocking has occurred in engine 10 based on the detection data of knock sensor 16. For example, the determination section is from 0° CA to 90° CA in the combustion stroke.

[0033] Here, due to the multi-stage fuel injection, the determination interval during the combustion stroke of each cylinder overlaps with the drive interval of the injector 12 during the compression stroke of any other cylinder. The determination interval does not overlap with the drive interval during the intake stroke. In Figure 2, the determination interval of the first cylinder overlaps with the drive interval of the third cylinder, the determination interval of the third cylinder overlaps with the drive interval of the fourth cylinder, the determination interval of the fourth cylinder overlaps with the drive interval of the second cylinder, and the determination interval of the second cylinder overlaps with the drive interval of the first cylinder.

[0034] During the drive period of the injector 12, vibrations occur when the valve is opened and closed as the injector 12 is driven to inject fuel. The vibrations generated by fuel injection during the drive period of the compression stroke are mixed as injector noise into the detection data detected by the knock sensor 16 during the determination period of the combustion stroke of the other cylinder.

[0035] 3 shows the difference between the detection data 200 indicated by the dotted line output by the knock sensor 16 when the injector 12 is injecting, and the detection data 202 indicated by the solid line output by the knock sensor 16 when the injector 12 is not injecting. It can be seen that the detection data 200 when the injector 12 is injecting varies more significantly than the detection data 202 when the injector 12 is not injecting.

[0036] If injector noise generated when the injector 12 is driven occurs in the determination section of another cylinder that is the subject of knocking determination, there is a risk that knocking may be erroneously determined to have occurred. Furthermore, if injector noise occurs as a vibration other than knocking when knocking occurs, it may not be possible to detect the occurrence of knocking.

[0037] Since the intensity of the injector noise hardly changes depending on the engine speed, the lower the engine speed and the smaller the vibration of the engine 10, the greater the cause of the vibration detected by the knock sensor 16 becomes due to the injector noise.

[0038] Therefore, in this embodiment, the occurrence of knocking is determined by removing injector noise that occurs in the drive interval of other cylinders that overlap with the judgment interval from the vibration of the engine 10 detected by the knock sensor 16 in the judgment interval of the cylinder that is the target of knocking judgment.

[0039] However, if the vibration of the engine 10 in the determination section where knocking may occur is removed as injector noise from the vibration of the engine 10, there is a possibility that the vibration due to knocking will also be removed.

[0040] Therefore, for other cylinders in which the injector 12 is driven during the compression stroke that overlaps with the determination section of the cylinder for which knocking is to be determined, the vibration generated when the injector 12 is driven during the intake stroke that does not overlap with the determination section of the cylinder for which knocking is to be determined is used as injector noise. In other words, this injector noise during the intake stroke is removed from the vibration of the engine 10 during the determination section of the cylinder for which knocking is to be determined.

[0041] Injector noise occurs when the injector 12 is driven to open and close, i.e., at the injection start and end timings. The injection start and end timings and injection duration may differ between the compression stroke and the intake stroke.

[0042] Therefore, when the injector noise during the intake stroke is used as the injector noise during the compression stroke, the injector noise is removed from the vibration of the engine 10 at a crank angle position different from the injector noise occurring in the determination section of the knocking determination target.

[0043] Therefore, in this embodiment, the crank angle position at which injector noise occurs during the intake stroke is corrected according to the injection start timing and injection end timing during the compression stroke, and is used as the injector noise occurring during the compression stroke. The injection start timing may be set based on the injection period and injection end timing, and the injection end timing may be set based on the injection period and injection start timing.

[0044] The injection start timing and injection end timing are determined based on the rising and falling timings of an injection command pulse that the knocking detection device 20 uses to instruct the injector 12 to inject fuel.

[0045] As shown in Figure 3, the injection start timing lags behind the rising timing of the injection command pulse. The injection end timing lags behind the falling timing of the injection command pulse. Taking these delays into account, the injection start timing and injection end timing are determined from the injection command pulse.

[0046] The vibration level of injector noise is approximately the same if the fuel pressure is the same. Furthermore, the fuel pressure rarely changes suddenly while the engine 10 is running. Therefore, the injector noise generated during the intake stroke of a cylinder whose compression stroke overlaps with the determination interval of the cylinder for which knocking is to be detected can be used as the injector noise generated during the determination interval.

[0047] [1-3. Processing] (1) Knocking detection processing Next, a description will be given of the knocking detection process executed by the knocking detection device 20. The flowchart of the knocking detection process shown in Fig. 4 is executed for each cylinder after the determination section shown in Fig. 2 ends, using the detection data acquired in the determination section.

[0048] In S400 of FIG. 4, the data acquisition unit 24 acquires the detection data detected by the knock sensor 16 in the determination interval. In S402, the vibration data unit 26 performs frequency component analysis on the acquired detection data. The frequency component analysis is to analyze the magnitude of the vibration level of the frequency components in the detection data. The vibration data unit 26 generates vibration data that represents the magnitude of the vibration level of the frequency components in a time series in the determination section as a two-dimensional map of frequency and crank angle.

[0049] In S404, the correction unit 30 refers to the noise data generated and stored by the noise data unit 28. This noise data is noise data of the injector 12 that is generated during the compression stroke of another cylinder and overlaps with the determination section of the cylinder that is the target of knocking determination. However, as described above, the crank angle position of the noise data of the injector 12 that is generated during the intake stroke of the other cylinder is corrected and the noise data is adopted as the noise data generated during the compression stroke.

[0050] As described above, the noise data is a two-dimensional map of frequency and crank angle, in which the magnitude of the vibration level of frequency components is represented in time series, similar to the vibration data generated in S402. The noise data is generated for each injector 12 of each cylinder.

[0051] 5, the correction unit 30 performs correction by subtracting the noise data of the injector 12 referred to by the noise data unit 28 in S404 from the vibration data generated by the vibration data unit 26 in S402. If the value obtained by subtracting the vibration level of the noise data from the vibration level of the vibration data at each coordinate is a negative value, the vibration level at the corresponding coordinate is set to 0.

[0052] By executing S406, corrected vibration data is generated from the vibration of the engine 10 detected by the knock sensor 16 in the judgment section of each cylinder, in which injector noise that occurs when the injector 12 of another cylinder is driven overlapping with the judgment section has been removed.

[0053] In S408, the knocking determination unit 32 refers to the determination reference data to determine whether or not knocking has occurred based on the corrected vibration data from which the injector noise has been removed in S406.

[0054] The determination reference data is data that defines which coordinates, expressed by frequency and crank angle, are to be used for determining whether knocking has occurred, with respect to the corrected vibration data. The generation of the criterion data will be described below.

[0055] Before the vehicle is shipped, the number of injections and injection timing of the injector 12 are controlled so that injector noise is not generated in the knock determination period, and the ignition timing is forcibly advanced to cause knocking.

[0056] Under these conditions, frequency component analysis is performed on each of the detection data acquired from knock sensor 16 over multiple cycles. Then, for each of the detection data that has undergone frequency component analysis, a two-dimensional map is generated in which time is converted into crank angles based on the engine speed, as in S402. Note that a cycle refers to a cycle in which each cylinder performs one intake stroke, compression stroke, combustion stroke, and exhaust stroke.

[0057] A plurality of two-dimensional maps generated in a plurality of cycles are compared, and the maximum value of the vibration level of the coordinates represented by the frequency and the crank angle is set. Then, as shown on the left side of Fig. 6, judgment reference data is generated in which the coordinate area where the maximum value of the set vibration level is equal to or greater than a predetermined value is displayed in black, and the coordinate area where the maximum value is less than the predetermined value is displayed in white.

[0058] In the determination reference data shown on the left side of Fig. 6, the black area indicates a determination area that is a target for knocking determination, and the white area indicates a non-determination area that is not a target for knocking determination.

[0059] In S410, the knocking determination unit 32 adds all vibration levels at coordinates corresponding to the determination region indicated in black in the determination reference data to the corrected vibration data from which the injector noise has been removed in S406. The determination region is indicated by a solid-line frame 210 on the right side of Figure 6.

[0060] Then, in S410, the knocking determination unit 32 determines that knocking has occurred if the value of the vibration level added up for all coordinates in the determination area is equal to or greater than a predetermined value. Depending on the type of engine 10 and vehicle, the vibration level of the engine 10 may always be high in a specific frequency range, regardless of whether knocking occurs. A frequency range in which the vibration level is high even when knocking does not occur is not suitable as judgment criterion data.

[0061] Therefore, when the low-frequency vibration level is high even when knocking is not occurring, only the high-frequency region is selected as the determination region, as shown in the lower left of Fig. 7. On the other hand, when the high-frequency vibration level is high even when knocking is not occurring, only the low-frequency region is selected as the determination region, as shown in the lower right of Fig. 7.

[0062] (2) Noise data generation process Next, a description will be given of the process of generating noise data of the injector 12 executed by the knocking detection device 20. The flowchart of the noise data generation process shown in Fig. 8 is executed when the drive section in which the injector 12 is driven ends during the intake stroke of each cylinder.

[0063] In S420 of FIG. 8, the data acquisition unit 24 acquires, as detection data of the knock sensor 16, vibrations generated by driving the injector 12 during the intake stroke of each cylinder where knocking does not occur, rather than during the determination section.

[0064] In S422, the noise data unit 28 performs frequency component analysis on the detection data acquired from the knock sensor 16. Then, for each piece of detection data that has been subjected to frequency component analysis, the noise data unit 28 generates noise data in the form of a two-dimensional map in which time is converted into crank angles based on the engine speed, in the same manner as in S402 of FIG.

[0065] In S424, the noise data unit 28 compares the maximum value set in the previous cycle with the vibration level value set in the current cycle for the vibration level of the coordinates represented by the crank angle and frequency of the noise data, as shown in Fig. 9. As a result of the comparison, the noise data unit 28 sets the larger value as the maximum value of the vibration level of the coordinates corresponding to the noise data.

[0066] If the determination in S426 is Yes, that is, if the maximum value of the vibration level for each coordinate of the noise data is set for the predetermined number of cycles of the intake stroke, the noise data unit 28 stores the noise data for which the maximum value is set in S428. The noise data stored in S428 is referenced in S404 of FIG. 4 described above.

[0067] [2.Effects] According to the embodiment described above, the following effects can be obtained. (2a) Since injector noise generated when the injector 12 is driven is removed from the detection data obtained from the knock sensor 16, it is possible to detect with high accuracy whether knocking is occurring based on the detection data obtained from the knock sensor 16.

[0068] (2b) The injector noise generated during the intake stroke of other cylinders where knocking is not occurring is used as the injector noise generated during the compression stroke of other cylinders that overlap with the detection interval of the cylinder for knocking detection. This allows noise data of the injector noise to be generated without being affected by vibrations caused by knocking.

[0069] (2c) The judgment criterion data is variably set based on the detection data obtained from the knock sensor 16 while the engine 10 is in operation after the vehicle is shipped, so that judgment criterion data that reflects changes over time can be generated.

[0070] (2d) The noise data is variably set based on the detection data obtained from the knock sensor 16 while the engine 10 is in operation after the vehicle is shipped, so that noise data that reflects changes over time can be generated.

[0071] (2e) Noise data is generated for each injector 12 of each cylinder, so that noise data is generated that incorporates differences in vibration characteristics of each injector 12 that arise due to differences in the distance between the knock sensor 16 and each injector 12.

[0072] (2f) For multiple noise data generated over a predetermined number of cycles, the maximum value of the vibration level at coordinates expressed by the crank angle and frequency is set as the vibration level value at the corresponding coordinate of the noise data. This ensures that injector noise is removed from the vibration data when the noise data is subtracted from the vibration data.

[0073] (2g) The crank angle is used as a unit of time series for vibration data and noise data. This allows the vibration data and noise data to be generated as a two-dimensional map of frequency and crank angle without being affected by changes in engine speed.

[0074] 3. Other Embodiments Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modifications.

[0075] (3a) In the above-described embodiment, the two-dimensional map of frequency versus time is converted into a two-dimensional map of frequency versus crank angle to remove injector noise from the vibration data. However, the injector noise may be removed from the vibration data in the form of a two-dimensional map of frequency versus time.

[0076] (3b) The vibration data and noise data of the injector 12 do not need to be expressed as a two-dimensional map of frequency versus time or crank angle, as long as frequency component analysis is performed on the data detected by the knock sensor 16 and the vibration level of the frequency components is expressed in time series.

[0077] (3c) In the above-described embodiment, noise data is generated for each injector 12 of each cylinder. However, noise data common to the injectors 12 of each cylinder may be generated. (3d) In the above-described embodiment, noise data generated over multiple cycles was compared, and the maximum value of the vibration level at the coordinates represented by the frequency and crank angle was used as the vibration level at the coordinates corresponding to the noise data used to correct the vibration data.

[0078] Alternatively, in noise data generated over a plurality of cycles, the average value of the vibration levels of coordinates represented by frequency and crank angle may be used as the vibration level of the coordinates corresponding to the noise data for correcting the vibration data.

[0079] (3e) In the above-described embodiment, the determination criterion data was variably set based on a plurality of corrected vibration data that were determined to indicate the occurrence of knocking during operation of the engine 10 after the vehicle was shipped. However, the determination criterion data may be generated by experiments or the like before the vehicle is shipped and used as fixed data.

[0080] (3f) In the above-described embodiment, the noise data is variably set based on the detection data obtained from the knock sensor 16 while the engine 10 is in operation after the vehicle is shipped. However, noise data generated for each fuel pressure by experiments or the like before the vehicle is shipped may be used as fixed data.

[0081] (3g) The knocking detection apparatus 20 and methods described in this disclosure may be implemented by a special purpose computer provided by configuring a processor and memory programmed to perform one or more functions embodied in a computer program.

[0082] Alternatively, the knock detection apparatus 20 and techniques described in this disclosure may be implemented by a special purpose computer provided by configuring a processor with one or more special purpose hardware logic circuits.

[0083] Alternatively, the knock detection apparatus 20 and techniques described herein may be implemented by one or more special purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits.

[0084] The computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium. The method for realizing the functions of the knocking detection device 20 and each of the components included therein does not necessarily need to include software, and all of the functions may be realized using one or more pieces of hardware.

[0085] (3h) In the above-described embodiments, multiple functions of one component may be realized by multiple components, and one function of one component may be realized by multiple components.

[0086] Furthermore, multiple functions possessed by multiple components may be realized by a single component, or a single function realized by multiple components may be realized by a single component. Also, part of the configuration of the above-described embodiments may be omitted. Furthermore, at least part of the configuration of the above-described embodiments may be added to or substituted for the configuration of another embodiment.

[0087] (3i) In addition to the knocking detection device 20 described above, the present disclosure can also be realized in various forms, such as a system including the knocking detection device 20 as a component, a program for causing a computer to function as the knocking detection device 20, a non-transient physical recording medium such as a semiconductor memory on which this program is recorded, and an electronic control method.

[0088] [Technical idea disclosed in this specification] [Item 1] A knocking detection device for detecting knocking in an internal combustion engine in which fuel is directly injected into a cylinder from an injector installed in each cylinder, a data acquisition unit configured to acquire detection data from a knock sensor that detects vibrations of the internal combustion engine; a vibration data unit configured to perform frequency component analysis on the detection data acquired by the data acquisition unit and generate vibration data representing vibration levels of frequency components in time series; a noise data unit configured to perform the frequency component analysis on the detection data acquired by the data acquisition unit when the injector is driven, and to generate noise data that represents, in time series, the vibration levels of the frequency components when the injector is driven; a correction unit configured to correct, based on the noise data, the vibration data generated by the vibration data unit based on the detection data acquired by the data acquisition unit in a determination section in which it is determined whether knocking has occurred; and a knocking determination unit configured to determine whether or not knocking has occurred based on the corrected vibration data generated by the correction unit; A knocking detection device comprising:

[0089] [Item 2] The knocking detection device according to item 1, the vibration data unit is configured to generate the vibration data as a two-dimensional map of frequency and the crank angle that changes over time, the noise data unit is configured to generate the noise data as the two-dimensional map of the frequency and the crank angle. Knock detection device.

[0090] [Item 3] The knocking detection device according to item 1 or 2, the noise data unit is configured to generate the noise data for each of the injectors installed in each cylinder. Knock detection device.

[0091] [Item 4] The knocking detection device according to any one of items 1 to 3, the noise data unit is configured to generate the noise data based on the detection data acquired by the data acquisition unit when the injector is driven in a section in which the knocking does not occur. Knock detection device.

[0092] [Item 5] Item 4. The knocking detection device according to item 4, The noise data unit and the correction unit are configured to set a section that is not the determination section as the section in which knocking does not occur. Knock detection device.

[0093] [Item 6] 6. A knocking detection device according to any one of items 1 to 5, the noise data unit is configured to compare a plurality of the noise data generated in a plurality of cycles, and to set a maximum value of the vibration level corresponding to the frequency component and the position on the time series as the vibration level corresponding to the frequency component and the position on the time series of the noise data when the correction unit corrects the vibration data. Knock detection device. [Explanation of symbols]

[0094] 10: Engine (internal combustion engine), 12: Injector, 16: Knock sensor, 20: Knock detection device, 24: Data acquisition unit, 26: Vibration data unit, 28: Noise data unit, 30: Correction unit, 32: Knock detection unit

Claims

1. A knocking detection device for detecting knocking in an internal combustion engine (10) in which fuel is directly injected into a cylinder from an injector (12) installed in each cylinder, comprising: a data acquisition unit (24, S400, S420) configured to acquire detection data from a knock sensor (16) that detects vibrations of the internal combustion engine; a vibration data unit (26, S402) configured to perform frequency component analysis on the detection data acquired by the data acquisition unit and generate vibration data representing vibration levels of frequency components in time series; a noise data unit (28, S422 to S428) configured to perform the frequency component analysis on the detection data acquired by the data acquisition unit when the injector is driven, and to generate noise data representing the vibration levels of the frequency components when the injector is driven in time series; a correction unit (30, S406) configured to correct, based on the noise data, the vibration data generated by the vibration data unit based on the detection data acquired by the data acquisition unit in a determination section for determining whether knocking has occurred, to generate corrected vibration data; a knocking determination unit (32, S410) configured to determine whether or not knocking has occurred based on the corrected vibration data generated by the correction unit; A knocking detection device comprising:

2. The knocking detection device according to claim 1, the vibration data unit is configured to generate the vibration data as a two-dimensional map of frequency and the crank angle that changes over time, the noise data unit is configured to generate the noise data as the two-dimensional map of the frequency and the crank angle. Knock detection device.

3. The knocking detection device according to claim 1 or 2, the noise data unit is configured to generate the noise data for each of the injectors installed in each cylinder. Knock detection device.

4. The knocking detection device according to claim 1 or 2, the noise data unit is configured to generate the noise data based on the detection data acquired by the data acquisition unit when the injector is driven in a section in which the knocking does not occur. Knock detection device.

5. The knocking detection device according to claim 4, The noise data unit and the correction unit are configured to set a section that is not the determination section as the section in which knocking does not occur. Knock detection device.

6. The knocking detection device according to claim 1 or 2, the noise data unit is configured to compare a plurality of the noise data generated in a plurality of cycles, and to set a maximum value of the vibration level corresponding to the frequency component and the position on the time series as the vibration level corresponding to the frequency component and the position on the time series of the noise data when the correction unit corrects the vibration data. Knock detection device.

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