Internal combustion engine control device

Abstract

To provide an internal combustion engine control device capable of improving detection accuracy of knocking when determining presence / absence of knocking of an internal combustion engine on the basis of an input result of a detection signal from a vibration sensor to a filter.SOLUTION: An ECU 40 includes: a processing device 43 performing processing for determining presence / absence of knocking on the basis of a detection signal from a vibration sensor 35 that detects vibration of an engine 1; and a storage device 41 storing information necessary for the determination made by the processing device 43. The processing device 43 includes: a filter processing section 53 inputting the detection signal from the vibration sensor 35 to at least one filter and extracting a vibration component of a specific frequency band; an integration calculation section 54 performing integration calculation on the basis of an output signal from the filter of the filter processing section 53; a knocking determination section 58 determining presence / absence of knocking on the basis of a calculation result obtained by the integration calculation section 54; and a knocking window correction section 52 correcting an integration period of the integration calculation section 54 relative to a preset period in accordance with filter properties.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to an internal combustion engine control device for controlling a positive displacement internal combustion engine, and more particularly to an internal combustion engine control device for determining whether or not knocking has occurred in the internal combustion engine based on a detection signal from a vibration sensor that detects vibrations in the internal combustion engine. [Background technology]

[0002] In positive displacement internal combustion engines (hereinafter sometimes referred to as "engines") such as reciprocating engines, a phenomenon known as knocking can occur during operation. Knocking is a phenomenon in which unburned gas at the end of the engine's combustion chamber self-ignites, generating a strong shock wave inside the combustion chamber that propagates to the engine body as vibration. Knocking is likely to occur during the engine's combustion stroke, and can be detected by a vibration sensor attached to the engine as vibration components in a frequency band specific to knocking.

[0003] One known technology for detecting engine knocking is a knocking detection device for an internal combustion engine described in Patent Document 1. This knocking detection device includes a knocking detector (vibration sensor) that detects vibration elements corresponding to the knocking phenomenon of an internal combustion engine, a filter circuit connected to the knocking detector and having a plurality of filters with filter characteristics for different frequency bands in a knocking frequency band, and a filter control circuit that selects a predetermined output from the plurality of filters depending on the engine state and outputs it from the filter circuit. This knocking detection device for an internal combustion engine switches between filters depending on the engine operating state, using a low-frequency band filter characteristic when vibration noise generated in the engine is relatively small in the low-frequency band, and conversely, using a high-frequency band filter when vibration noise is large in the low-frequency band. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 56-000637 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, a method for detecting knocking involves frequency analysis of the detection signal of a vibration sensor within a knock window, which indicates a period during which engine knocking may occur, in order to separate vibrations (noise) generated during operation of an injector, a valve, etc., from vibrations specific to knocking. The knock window can be set in advance as a predetermined range of the crank angle detected by a crank angle sensor, for example. Let us consider a case in which a method for detecting knocking within such a limited period (knock window) is applied to the knocking detection device for an internal combustion engine described in Patent Document 1.

[0006] In the knocking detection device for an internal combustion engine described in Patent Document 1, a detection signal from a vibration sensor is input to a selected filter from among multiple filters in a filter circuit to extract vibration components in a frequency band specific to knocking. However, a response delay may occur depending on the characteristics of the selected filter. With a filter with such characteristics, even if a vibration component indicating the occurrence of knocking is input, at least a portion of the filter's output waveform may fall outside a preset knock window due to the response delay. In this case, the knocking determination is made without taking into account the output waveform that falls outside the knock window, which raises concerns about an erroneous determination that misses the occurrence of knocking.

[0007] The present invention has been made to solve the above problems, and its purpose is to provide an internal combustion engine control device that can improve the accuracy of knocking detection when determining whether or not knocking occurs based on the result of inputting the detection signal of a vibration sensor into a filter. [Means for solving the problem]

[0008] The present application includes a plurality of means for solving the above-mentioned problems. One example is an internal combustion engine control device including a processing device that performs a process of determining whether or not knocking has occurred in the internal combustion engine based on a detection signal from a vibration sensor that detects vibrations in the internal combustion engine, and a storage device that stores information necessary for the determination process of the processing device, wherein the processing device includes a filter processing unit that inputs the detection signal from the vibration sensor to at least one filter to extract vibration components in a specific frequency band, an integration calculation unit that performs an integration calculation based on an output signal from the filter of the filter processing unit, a determination unit that determines whether or not knocking has occurred in the internal combustion engine based on the calculation result of the integration calculation unit, and a period correction unit that corrects an integration period of the integration calculation unit with respect to a preset period in accordance with the characteristics of the filter. the filter processing unit has a plurality of filters having different characteristics from each other, and the plurality of filters are configured to differ in at least one of the center frequency of a frequency band for extracting vibration components, the width of the frequency band for extracting vibration components, the filter order, and the filter type; the filter processing unit is configured to process the detection signal of the vibration sensor using the plurality of filters; the integral calculation unit is configured to perform an integral calculation based on the output signal of each of the plurality of filters; the period correction unit is configured to correct the integral period of the integral calculation unit in accordance with the characteristics of each of the plurality of filters; the storage device has stored in advance a correction amount map in which the correction amount of the integral period of the integral calculation unit is set for each of the plurality of filters in accordance with the characteristics of each of the plurality of filters; and the period correction unit of the processing device is configured to correct the start point and end point of the integral period of the integral calculation unit using the correction amount determined from the correction amount map. . [Effects of the Invention]

[0009] According to the present invention, by correcting the integration period of the integration calculation performed by the integration calculation unit based on the output signal of the filter with respect to a preset period in accordance with the characteristics of the filter, it is possible to reduce the effect of the response delay (characteristics) of the filter on the integration period of the integration calculation, thereby suppressing erroneous determination of the presence or absence of knocking determined based on the calculation result of the integration calculation.In other words, it is possible to improve the accuracy of knocking detection when determining the presence or absence of knocking based on the result of inputting the detection signal of the vibration sensor to the filter. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram showing an internal combustion engine system including an internal combustion engine control device according to an embodiment of the present invention. [Figure 2] 2 is a block diagram showing the hardware configuration of the internal combustion engine control device according to the embodiment of the present invention shown in FIG. 1. FIG. [Figure 3]FIG. 10 is a diagram showing an example of an analysis result of frequency components of vibrations of an internal combustion engine when knocking is not occurring in the internal combustion engine. [Figure 4] 4 is a characteristic diagram showing an example of an analysis result of frequency components of vibrations of an internal combustion engine when knocking occurs in the internal combustion engine. [Figure 5] FIG. 3 is an explanatory diagram showing an example of a method for determining whether or not knocking has occurred in an internal combustion engine. [Figure 6] 10 is an explanatory diagram showing an erroneous determination of the occurrence of knocking due to a response delay of a filter that extracts frequency components specific to knocking; FIG. [Figure 7] 3 is a block diagram showing a function of knocking determination in the internal combustion engine control device according to the embodiment of the present invention shown in FIG. 2. FIG. [Figure 8] 8 is a diagram showing an example of settings of knock window correction amounts (knock window correction map) for the filters in the knock window correction unit of the internal combustion engine control device according to the embodiment of the present invention shown in FIG. 7. FIG. [Figure 9] FIG. 9 is an explanatory diagram showing a method for determining the knock window correction amount (knock window correction map) shown in FIG. [Figure 10] 8 is a diagram showing another example of settings of knock window correction amounts (knock window correction map) for the filters in the knock window correction unit of the internal combustion engine control device according to the embodiment of the present invention shown in FIG. 7. FIG. [Figure 11] 8 is a flowchart showing an example of a procedure for determining knocking in the internal combustion engine control device according to the embodiment of the present invention shown in FIG. [Figure 12] 12 is a flowchart showing an example of a process procedure for selecting and switching filters in the flowchart of knocking determination of the internal combustion engine control device according to the embodiment of the present invention shown in FIG. [Figure 13] 12 is a flowchart showing an example of a processing procedure for correcting a knock window in the flowchart of knocking determination of the internal combustion engine control device according to the embodiment of the present invention shown in FIG. [Figure 14]5 is a time chart showing an example of a corrected knock window and a filter switching timing in knocking determination of an internal combustion engine control device according to an embodiment of the present invention. [Figure 15] 3 is a flowchart showing an example of a processing procedure for calculating the ignition timing of the engine in the internal combustion engine control device according to the embodiment of the present invention shown in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an internal combustion engine control device according to the present invention will now be described with reference to the accompanying drawings. In the present embodiment, a reciprocating engine will be described as an example of an object to be controlled by the internal combustion engine control device.

[0012] First, a schematic configuration of an internal combustion engine system including an internal combustion engine control device according to an embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a schematic configuration diagram showing an internal combustion engine system including an internal combustion engine control device according to an embodiment of the present invention.

[0013] In Figure 1, internal combustion engine 1 (hereinafter referred to as engine) is a spark-ignition reciprocating engine mounted, for example, on an automobile as a prime mover, and includes multiple cylinders 2 (only one is shown in Figure 1), a cylinder head 3 attached to one side of the cylinders 2, pistons 4 arranged to be able to reciprocate within each cylinder 2, and a crankshaft 5 that converts the reciprocating motion of pistons 4 into rotational motion. Cylinder head 3 is provided with intake valves 6 and exhaust valves 7 that open and close. A combustion chamber 9 is formed by cylinders 2, cylinder head 3, pistons 4, intake valves 6, and exhaust valves 7.

[0014] The engine 1 has an injector 11 corresponding to each cylinder 2. The injector 11 is disposed, for example, upstream of the intake valve 6 and injects fuel supplied from a fuel tank (not shown). The injector 11 may be of a direct injection type that injects fuel directly into the cylinder 2.

[0015] Spark plugs 13 corresponding to each cylinder 2 are arranged in the cylinder head 3 so as to face the combustion chamber 9. The spark plugs 13 of each cylinder 2 are electrically connected to an ignition coil 14 via a distributor 15. As a result, the high voltage generated by the ignition coil 14 is distributed by the distributor 15 and supplied to the spark plugs 13 of each cylinder 2.

[0016] An intake pipe 21 is provided on the intake valve 6 side of the engine 1 and is connected to an air cleaner 23 via a duct 22. The air cleaner 23 filters the air taken into the engine 1. A throttle valve 24 that can adjust the amount of air taken in is disposed in the intake pipe 21. An exhaust pipe 26 is provided on the exhaust valve 7 side of the engine 1.

[0017] An air flow sensor 31 is installed in the duct 22 on the upstream side of the intake pipe 21. The air flow sensor 31 detects the amount of intake air (the amount of air flowing through the duct 22) and outputs a detection signal corresponding to the detected amount of intake air to an internal combustion engine control device 40, which will be described later. A throttle opening sensor 32 is installed in the throttle valve 24 and detects the throttle opening of the throttle valve 24.

[0018] An exhaust sensor 33 is installed in the exhaust pipe 26. The exhaust sensor 33 detects the concentration of components (e.g., oxygen concentration) contained in the exhaust gas from the engine 1, and outputs a detection signal corresponding to the detected concentration of the component to an internal combustion engine control device 40, which will be described later.

[0019] A crank angle sensor 34 is provided on the crankshaft 5. The crank angle sensor 34 is capable of detecting the crank angle and engine speed. The crank angle sensor 34 outputs, for example, a Ref signal indicating a reference position (Ref position) for each rotation of the crankshaft 5 and a Pos signal indicating a position moved a predetermined angle from the reference position to an internal combustion engine control device 40, which will be described later.

[0020] A vibration sensor 35 that detects vibrations of the engine 1 is installed in the cylinder 2. The vibration sensor 35 outputs a detection signal corresponding to the detected vibrations to an internal combustion engine control device 40, which will be described later.

[0021] In the internal combustion engine system configured as described above, air that has passed through the air cleaner 23 has its flow rate adjusted by the throttle valve 24 and is then mixed with fuel injected into the intake pipe 21 from the injector 11. This air-fuel mixture is drawn into the combustion chamber 9 of the engine 1. The mixture in the combustion chamber 9 is compressed by the piston 4 and ignited by the spark plug 13. After explosion, the mixture is discharged to the outside via the exhaust pipe 26.

[0022] The internal combustion engine control device 40 is an electronic control device (hereinafter, sometimes referred to as an ECU (Electric Control Unit)) that manages overall control of the engine 1 based on various types of information. The ECU 40 according to this embodiment determines whether or not knocking has occurred in the engine 1, and executes processing to calculate the ignition timing of the engine 1 according to the determination result.

[0023] Next, the hardware configuration of the ECU according to one embodiment of the present invention will be described with reference to Fig. 2. Fig. 2 is a block diagram showing the hardware configuration of the ECU according to one embodiment of the present invention shown in Fig. 1.

[0024] The ECU 40 receives detection signals from various sensors, calculates the amount of fuel supply, ignition timing, etc. based on the received detection signals, and outputs control signals according to the calculation results to the injector 11, the ignition coil 14, and the throttle valve 24 (drive motor). The ECU 40 is equipped with a microcomputer including a ROM 41 (Read Only Memory) and a RAM 42 (Random Access Memory) as storage devices, an MPU 43 (Micro Processor Unit) as a processing device, an input circuit 44, and a driver 45. The ROM 41, the RAM 42, and the MPU 43 are connected via a bus 46.

[0025] The ROM 41 stores various programs for controlling the engine 1, such as determining knocking and calculating the fuel supply amount and ignition timing. It also stores information necessary for the MPU 43 to make the determinations described below. The input circuit 44 converts various input detection signals (analog signals) into digital signals, such as a detection signal corresponding to the intake air amount Q detected by the airflow sensor 31, a Ref signal (Ref position) and a Pos signal detected by the crank angle sensor 34, a detection signal from the exhaust sensor 33, a detection signal V corresponding to vibration detected by the vibration sensor 35, a detection signal from the throttle opening sensor 32, a detection signal from the accelerator opening sensor 37 that detects the accelerator opening, and a detection signal from the engine water temperature sensor 38 that detects the engine water temperature. The MPU 43 executes various calculations according to the programs read from the ROM 41. The RAM 42 temporarily stores various data necessary for the MPU 43 to perform calculations. The driver 45 generates various control signals such as a fuel injection time signal indicating the fuel injection amount, an ignition timing signal indicating the ignition timing, and an opening signal indicating the opening of the throttle valve 24 according to the calculation results of the MPU 43, and outputs the generated control signals to various actuators such as the injector 11, the ignition coil 14, and the throttle valve 24 (drive motor).

[0026] The ECU 40 of this embodiment determines whether or not knocking has occurred in the engine 1 based on the output signal V of the vibration sensor 35 in accordance with a program stored in the ROM 41, and adjusts the ignition timing of the engine 1 according to the determination result.

[0027] <General principles of knock detection> Next, a general method for detecting engine knocking will be described with reference to Figures 3 to 5. When an engine knocks, vibrations specific to the knocking occur in the engine. However, engine vibrations contain many vibration components caused by piston friction, crankshaft rotation, and operation of intake and exhaust valves. Moreover, these vibration components change depending on the operating state of the engine. Therefore, whether knocking has occurred is determined by separating the vibrations specific to the knocking from the vibrations of the entire engine detected by a vibration sensor. The separation of the vibrations detected by the vibration sensor is performed using a filter with characteristics that allow only a predetermined frequency band to be extracted.

[0028] FIG. 3 is a diagram showing the analysis results of the frequency components of the detection results (output) of the vibration sensor when the engine is not knocking. Note that this analysis result is for when the engine is in a first operating state (a certain engine speed). This analysis result illustrates an example of a range slightly exceeding 20 kHz. However, the analysis range of frequency components for knocking is not limited to this range. The same applies to the following diagrams of analysis results.

[0029] Fig. 4 is a diagram showing the analysis results of the frequency components of the detection results (output) of the vibration sensor when knocking occurs in the engine. The analysis results are for two different operating states of the engine: a first operating state (a relatively low first engine speed) and a second operating state (a relatively high second engine speed). In Fig. 4, the solid line D1 shows the analysis results for the first operating state, and the dotted line D2 shows the analysis results for the second operating state.

[0030] Comparing Figure 3 and Figure 4, it can be seen that when knocking occurs, there are vibration components of multiple different resonance frequencies compared to when knocking does not occur. It can be seen that the vibration components of these resonance frequencies are vibration components in the frequency band specific to knocking. For example, the frequency f 10 , f 01 , f 11Knocking accompanied by vibrations in the frequency range occurs.

[0031] Furthermore, from a comparison of the analysis results D1 and D2 in FIG. 4, it can be seen that the frequency band specific to knocking changes depending on the difference in the engine operating state (difference in engine speed). For example, in the first operating state, the frequency f 10 , f 01 , f 11 On the other hand, in the second operating state, knocking occurs with vibrations in the frequency band g 10 , g 01 , g 30 , g 11 Knocking occurs accompanied by vibrations in the frequency range (see dotted line D2).

[0032] Therefore, by switching the setting of the frequency band extracted by the filter in response to changes in the operating state of the engine, it becomes possible to separate the vibration components in the frequency band specific to knocking, which changes depending on the operating state of the engine, thereby enabling highly reliable determination of whether knocking has occurred.

[0033] 5 is a diagram illustrating the general principle of determining whether or not knocking occurs by using a knocking determination index. In the following description, for convenience, the resonance frequency f 10 (approx. 6.3KHz) and f 01 An example will be described in which the knocking determination index is calculated using the vibration intensity of a resonance frequency (approximately 18.0 KHz). However, the vibration intensity of the resonance frequency for calculating the knocking determination index is not limited to this, and the vibration intensity of any two or more resonance frequencies can be used.

[0034] The vibration sensor detects a combination of vibration caused by knocking and background vibration (vibration caused by factors other than knocking). When knocking is not occurring, the knocking determination index I becomes index Ib corresponding to the background vibration. On the other hand, when knocking occurs, the knocking determination index I is calculated by combining index Ib corresponding to the background vibration and index Ik corresponding to the vibration caused by knocking.

[0035] Specifically, the knocking determination index I can be expressed by the following equation (1) using the vibration components of the main resonance frequencies shown in FIG. 4. P(f) is the vibration intensity of the resonance frequency f. ω is a real value determined by the engine speed. Note that ω can also take on two values, 1 and 0.

[0036] I=ω 10 P(f 10 )+ω 20 P(f 20 )+ω 01 P(f 01 )+ω 11 P(f 11 ) … Formula (1) As shown in Figure 5, the index Ib, which is indicated by the vibration intensity of the resonance frequency of background vibration, and the index Ik, which is indicated by the vibration intensity of the resonance frequency caused by the occurrence of knocking, have different directions and magnitudes. This corresponds to the fact that, as is clear from hearing tests conducted by humans, the engine sound when there is no knocking can be distinguished from the sound, for example, a crunching sound, when knocking occurs.

[0037] The knocking judgment index I is the threshold I when the vibration caused by knocking is added to the background vibration. th The knocking determination index I exceeds the threshold value I th If it exceeds the above, it is determined that knocking has occurred. Note that the knocking determination index (hereinafter referred to as the knock index) is defined as an index calculated using a combination of vibration components of multiple resonance frequencies contained in the output of the vibration sensor, not limited to the four terms on the right side of equation (1).

[0038] In this way, the knock indicator is calculated by taking into consideration not only background vibration but also vibration of a specific frequency component due to the occurrence of knocking. Therefore, even if the background vibration becomes large, it is possible to determine whether knocking has occurred.

[0039] <Basic Concept of Knocking Detection in the Present Embodiment> The ECU 40 according to this embodiment performs the following calculations when calculating the knock indicator. By constantly filtering the detection signal (vibration of the engine 1) output from the vibration sensor 35, the ECU 40 extracts vibration components in a frequency band specific to knocking based on the detection signal from the vibration sensor 35. The vibration components in the frequency band specific to knocking extracted by the filter (filter output) are integrated over a preset knock window as an integration interval (integration period). The result of this integration calculation is compared with a threshold value to determine whether knocking has occurred. The knock window is a period during which knocking may occur in the engine 1, and is preset, for example, as a predetermined range of crank angles. The determination of knocking is made based on the magnitude of an integral value of the period during which knocking may occur, based on the filter output. A filter having characteristics corresponding to a frequency band specific to knocking, which varies depending on the operating state of the engine 1 (for example, engine speed), is selected as the filter for processing the detection signal from the vibration sensor 35.

[0040] However, depending on the characteristics of the selected filter, even if a vibration component indicating the occurrence of knocking is input, at least a portion of the output waveform of the filter may fall outside the knock window, which is a preset integration period, due to a response delay. In this case, the knocking determination is made without taking into account the portion of the filter output waveform that falls outside the knock window, which raises the concern of an erroneous determination that the occurrence of knocking is overlooked.

[0041] Figure 6 shows an example of the principle behind the incorrect determination of whether or not knocking has occurred due to a filter's response delay (characteristics). In Figure 6, Filter A and Filter B have the same center frequency and frequency bandwidth, but Filter B has a higher order than Filter A. The same vibration waveform indicating the occurrence of knocking is input to Filter A and Filter B, which have such characteristics.

[0042] In filter A, the entire output waveform indicating the occurrence of knocking falls between the start point Ws and the end point We of the knock window. Therefore, if the knock window is used as the integration period and the output waveform of filter A is integrated, the occurrence of knocking can be accurately determined.

[0043] In contrast, with Filter B, a portion of the output waveform indicating the occurrence of knocking falls outside the knock window due to a response delay of the filter. For this reason, if the presence or absence of knocking is determined using the result of integrating the output waveform of Filter B using the knock window as the integration period, it will erroneously be determined that knocking is not occurring, even though knocking is actually occurring.

[0044] Furthermore, if noise that is not attenuated by the processing of filter A or filter B occurs immediately before the start point Ws of the knock window, there is a concern that the noise component will enter the knock window due to the response delay of filter A or filter B. In this case, there is a risk of erroneously determining that knocking is occurring even when it is not.

[0045] The ECU 40 of this embodiment corrects the start and end points of the knock window, which is used as the integration period for the integral calculation performed to calculate the knock indicator, according to the characteristics of the filter, thereby reducing erroneous determination of knocking due to a response delay of the filter, thereby improving the accuracy of knocking detection regardless of whether the engine 1 is operating steadily or transiently.

[0046] Next, the knocking determination function section in the ECU according to one embodiment of the present invention will be described with reference to Figures 7 to 10. Figure 7 is a block diagram showing the knocking determination function in the internal combustion engine control device according to one embodiment of the present invention shown in Figure 2.

[0047] 7, the ECU 40 includes functional units such as a filter switching unit 51, a knock window correction unit 52, a filter processing unit 53, a filter output integration calculation unit 54, an overall intensity calculation unit 55, a smoothing processing unit 56, a knock index calculation unit 57, and a knock determination unit 58 as processing functions of the MPU 43 (see FIG. 2) that determines whether knocking has occurred based on the detection signal of the vibration sensor 35. The ECU 40 changes the ignition timing of the spark plug 13 depending on the determination results of the functional units 51 to 58, that is, whether knocking has occurred. The control by the ECU 40 that changes the ignition timing of the spark plug 13 depending on whether knocking has occurred will be outlined later (see FIG. 15, which will be described later).

[0048] The filter switching unit 51 selects and switches the filter used in the filter processing unit 53 depending on the operating state of the engine 1. The resonance frequency specific to the vibration caused by knocking changes depending on the operating state of the engine 1. Therefore, the filter switching unit 51 selects a filter having a characteristic capable of extracting the vibration component of the resonance frequency specific to knocking corresponding to the operating state of the engine 1. For example, in the case of the first operating state shown in FIG. 4, the filter having the frequency f 01 Frequency bands including frequency f 10 In the second operating state shown in FIG. 4, the frequency g 10 , frequency g 01 , frequency g 30 , frequency g 11The filter switching unit 51 can be configured to select a plurality of filters having characteristics capable of extracting vibration components in a frequency band including the frequency components of the above. As the filter, a high-pass filter, a low-pass filter, a band-pass filter, or the like can be used. For example, the filter switching unit 51 can be implemented by an FIR filter or an IIR filter. The filter switching unit 51 is configured to execute a process of selecting and switching filters in response to the input of the Ref signal from the crank angle sensor 34. That is, the filter switching by the filter switching unit 51 is performed when the position of the crankshaft 5 detected by the crank angle sensor 34 reaches the Ref position.

[0049] The knock window correction unit 52 corrects the knock window (the integration period of the filter output integration calculation unit 54) according to the characteristics of the filter selected and switched by the filter switching unit 51. Specifically, the correction amount is calculated using a window correction amount map, and the start and end points of the knock window are corrected using the calculated correction amount. The Ref position (the reference position of the crankshaft 5) and the start and end points of the knock window are set in advance and stored in the ROM 41. The window correction amount map is a map in which correction amounts are set in advance for each of a plurality of filters and the correction amount is output by map search, and is pre-stored in the ROM 41. The Ref position indicates the filter switching timing (switching position) of the filter processing unit 53. The end point of the knock window is basically corrected using the correction amount in the window correction amount map. However, if the end point of the knock window corrected using the correction amount in the window correction amount map exceeds the Ref position, the end point of the knock window is corrected using the Ref position. This is to prevent the filter from being switched during the corrected knock window as an integration period.

[0050] Fig. 8 is an example of a window correction amount map. In the window correction amount map M1 shown in Fig. 8, +Ta is set as the window correction amount for filter A, and +Tb is set as the window correction amount for filter B. The window correction amount is set in accordance with the characteristics of filter A and filter B. This window correction amount map M1 is based on the output when no filter is used, and the correction amount is determined, for example, as follows.

[0051] Figure 9 shows the response delays of Filter A and Filter B, with the output without the filter as the reference, when a sine waveform of the same frequency is input to each of Filter A, Filter B, and Filter B. Filter A has characteristics of frequency bandwidth A1, center frequency A2, and filter order A3. Filter B has characteristics of frequency bandwidth B1, center frequency B2, and filter order B3.

[0052] The rise time of the sine waveform when no filter is used is taken as the reference time T0. In this case, the output of filter A is delayed in response by time Ta until the rise of the sine waveform. On the other hand, the output of filter B is delayed in response by time Tb until the rise of the sine waveform. The response delay of filter A over time Ta and the response delay of filter B over time Tb are set as the correction amounts of filter A and filter B in the window correction amount map, respectively. These correction amounts Ta and Tb can be obtained in advance as times or angles by measurement or calculation.

[0053] The window correction amount map M1 shown in Fig. 8 sets the amount of correction compared to when there is no filter. However, the window correction amount map can also set the amount of correction based on the response delay of the reference filter. Fig. 10 shows another example of a window correction amount map. In the window correction amount map M2 shown in Fig. 10, filter B is used as the reference filter, and the response delay of filter B is set to 0, while the response delay of filter A is set to Ta - Tb (< 0).

[0054] When the knock window is adapted without a filter, the window correction amount map M1 shown in Fig. 8 is used. On the other hand, when the knock window is adapted using filter B as the reference filter, the window correction amount map M2 shown in Fig. 10 is used.

[0055] The filter processing unit 53 processes the detection signal of the vibration sensor 35 (the A / D value converted by the A / D conversion of the input circuit 44) using the filter selected and switched by the filter switching unit 51, extracts and outputs vibration components in a specific frequency band. As described in the description of the filter switching unit 51, the filter processing unit 53 can use a plurality of filters having different characteristics, and these plurality of filters each output.

[0056] Filter output integral calculation unit 54 performs integration based on the filter output, using the knock window corrected by knock window correction unit 52 as the integration interval (integration period). This integral calculation integrates the absolute value of the filter output value. When multiple filters are used, the absolute value of the output value of each filter is integrated. For example, filter output integral calculation unit 54 integrates the absolute value of the vibration component of each frequency band specific to knocking. In other words, it calculates the vibration intensity of each frequency band.

[0057] The overall intensity calculation unit 55 adds up all integral values ​​based on the output from each filter of the calculation results of the filter output integral calculation unit 54. For example, the overall intensity calculation unit 55 adds up all integral values ​​of vibration components in each frequency band specific to knocking, thereby calculating the overall vibration intensity F including multiple frequency bands specific to knocking.

[0058] The smoothing processing unit 56 calculates a background level BGL by smoothing processing. The background level BGL is, for example, a weighted average of the overall intensity F calculated by the overall intensity calculation unit 55 and the calculation result of the smoothing processing unit 56 in the previous knocking determination cycle.

[0059] The knock indicator calculation unit 57 calculates the SN ratio as a knock indicator. The SN ratio is calculated by dividing the overall intensity F calculated by the overall intensity calculation unit 55 by the background level BGL calculated by the smoothing processing unit 56 (SN ratio = F / BGL).

[0060] The knock determination unit 58 determines whether knocking has occurred by comparing the knock index (SN ratio) calculated by the knock index calculation unit 57 with a threshold value. If the knock index (SN ratio) is greater than the threshold value, it determines that knocking has occurred, and otherwise it determines that knocking has not occurred. The threshold value used for the determination is, for example, preset and stored in the ROM 41. Note that the threshold value can also be configured to be changed depending on the operating conditions, etc. For example, it is possible to use a map that defines in advance the correspondence between the operating conditions, such as the engine speed and engine water temperature, and the threshold value.

[0061] Next, an example of a processing procedure for knocking determination in an ECU according to an embodiment of the present invention will be described with reference to Figures 11 to 13. Figure 11 is a flowchart showing an example of the processing procedure for knocking determination in an internal combustion engine control device according to an embodiment of the present invention shown in Figure 7. Figure 12 is a flowchart showing an example of the processing procedure for filter selection and switching in the flowchart for knocking determination in an internal combustion engine control device according to an embodiment of the present invention shown in Figure 11. Figure 13 is a flowchart showing an example of the processing procedure for correcting a knock window in the flowchart for knocking determination in an internal combustion engine control device according to an embodiment of the present invention shown in Figure 11. The flowchart shown in Figure 11 is executed for each explosion cycle of the engine 1, and is executed by the MPU 43 shown in Figure 2 by issuing an interrupt to the MPU 43.

[0062] 11, the MPU 43 (filter switching unit 51 shown in FIG. 7) first selects and switches the filter used in the filter processing unit 53 shown in FIG. 7 according to the operating state of the engine 1 (step S101). Specifically, at the timing when the Ref signal detected by the crank angle sensor 34 rises, information such as the engine speed, engine load, engine water temperature, and combustion cylinder is read from the RAM 42, and the operating state of the engine 1 is determined based on the read information. Furthermore, a filter corresponding to the determined operating state is selected, and the selected filter is set as the filter of the filter processing unit 53.

[0063] An example of a specific processing procedure of step S101 for selecting and switching a filter will be described with reference to Fig. 12. In order to ensure sufficient time for the filter output to stabilize after filter switching, the flowchart shown in Fig. 12 starts execution, for example, at the Ref position (rising edge of the Ref signal) that is earlier than the start point (start position) of the knock window.

[0064] The MPU 43 (filter switching unit 51) first reads the engine speed N as information on the operating state from the RAM 42 (step S201), and compares and determines whether the read engine speed N is greater than a threshold value Nc read from the ROM 41 (step S202). If the engine speed N is equal to or less than the threshold value Nc, i.e., if the answer is NO in step S202, the filter A (see FIG. 9) described above is set as the filter to be used in the filter processing unit 53 (step S203). On the other hand, if the engine speed N is less than the threshold value Nc, i.e., if the answer is YES in step S202, the filter B (see FIG. 9) described above is set as the filter to be used in the filter processing unit 53 (step S204).

[0065] For simplicity of explanation, this flowchart shows an example in which two types of filters are selected depending on the engine speed N. However, it is also possible to configure the system so that filter characteristics are switched based on engine load or engine water temperature information or for each combustion cylinder, and it is also possible to configure the system so that multiple filters are switched at the same time.

[0066] Returning to FIG. 11, the MPU 43 (knock window correction unit 52 shown in FIG. 7) calculates the amount of correction for the knock window corresponding to the filter selected in step S101, and corrects the start and end points of the knock window based on the calculated amount of correction (step S102). This correction is performed for each selected filter. An example of a specific processing procedure for correcting the knock window in step S102 will be described with reference to FIG. 13.

[0067] 13, the MPU 43 (knock window correction unit 52) ​​reads information about the filter selected in step S101 from the ROM 41 (step S301). In addition, information about the reference start point Wsb, the reference end point Web, and the Ref position of the preset knock window is read from the ROM 41 (step S302).

[0068] Next, the MPU 43 calculates the knock window correction amount T dly Specifically, for example, by searching the window correction amount map M1 shown in FIG. 8, the correction amount corresponding to the filter selected in step S101 is calculated as the correction amount T dly Although the example in which the map M1 shown in FIG. 8 is used as the window correction amount map has been shown, a configuration in which the map M2 shown in FIG. 10 is used is also possible.

[0069] Next, the MPU 43 sets the corrected start point Ws of the knock window (step S304). Specifically, the corrected start point Wsc of the knock window is calculated by multiplying the reference start point Wsb of the knock window by the correction amount T calculated in step S303. dlyThat is, Wsc=Wsb+T dly This becomes:

[0070] Next, the MPU 43 calculates the correction amount T calculated in step S303 for the reference end point Web of the knock window. dly It is determined whether the calculation result obtained by adding Web+T exceeds (is ahead of) the Ref position (step S305). dly > Determine whether it is a Ref.

[0071] If the determination in step S305 is NO, the corrected end point Wec of the knock window is calculated by subtracting the correction amount T calculated in step S303 from the reference end point Web of the knock window. dly The result of the addition is set (step S306). That is, Wec=Web+T dly is.

[0072] On the other hand, if the determination in step S305 is YES, the Ref position is set as the corrected end point Wec of the knock window (step S307). That is, Wec = Ref. The reason for setting the Ref position as the corrected end point Wec of the knock window in step S307 is that, since filter selection switching by filter switching unit 51 (step S101) is performed at the Ref position, the corrected end point Wec of the knock window (i.e., the end point of the integration interval for the integration calculation of the filter output) must be prevented from occurring after the Ref position (filter switching position).

[0073] In this way, the MPU 43 is configured to correct the start and end points of the knock window by executing the series of processes in steps S301 to S307.

[0074] 11, the MPU 43 receives an A / D value obtained by A / D conversion of the detection signal from the vibration sensor 35 via the input circuit 44 (step S103). In step S103, it is possible to buffer the detection signal from the vibration sensor 35 within a specific angle range that can be calculated from the detection value of the crank angle sensor 34, and to receive the buffered signal data at the timing of an interrupt process to the MPU 43. Furthermore, when the filter processing unit 53 shown in FIG. 7 is realized by hardware such as a circuit device, it is also possible to constantly receive the detection signal from the vibration sensor 35 at a predetermined sampling rate.

[0075] Next, the MPU 43 (filter processing unit 53) extracts vibration components in a frequency band specific to knocking from the captured A / D value using the filter selected and switched in step S101 (step S104). Although only one filter is selected in the flowchart shown in Fig. 12, multiple filters can be used depending on the frequency components specific to knocking.

[0076] Next, the MPU 43 (filter output integration unit 54 shown in FIG. 7) uses the knock window corrected in step S102 as the integration period and performs integration based on the filter output resulting from the processing in step S104 (step S105). That is, in this integration calculation, the corrected start point Wsc of the knock window is set as the start point of the integration interval and the corrected end point Wec of the knock window is set as the end point of the integration interval according to the processing result of step S102, and the absolute value of the filter output is integrated over the set integration interval. This integration calculation is performed separately for the output of each filter, and the integration interval (knock window) is corrected according to the characteristics of each filter.

[0077] Next, the MPU 43 (total intensity calculation unit 55 shown in FIG. 7) calculates total intensity F of the multiple frequency bands corresponding to the multiple filters by adding up all of the integral values ​​f1, f2, f3, ... of the multiple filter outputs, which are the calculation results of step S105 (step S106). Since the multiple frequency bands match frequency components specific to knocking, it is possible to improve the accuracy of knocking detection.

[0078] Furthermore, the MPU 43 (knock index calculation unit 57 shown in FIG. 7) calculates the S / N ratio as the knock index S (step S107). Specifically, the S / N ratio is calculated by dividing the overall intensity F calculated in step S106 by the background level BGL calculated by the smoothing processing unit 56 shown in FIG. 7 (the calculation result in step S109, described below, in the previous cycle of knocking determination). That is, S=F / BGL.

[0079] The MPU 43 (knock determination unit 58 shown in FIG. 7) compares the knock index S calculated in step S107 to determine whether it is greater than a threshold value (step S108). If the knock index S is greater than the threshold value (YES), the process proceeds to step S111, and otherwise (NO), the process proceeds to step S109.

[0080] If the result in step S108 is NO, the MPU 43 determines that knocking has not occurred, updates the background level BGL (step S109), and sets a knock determination flag indicating the determination that knocking has occurred to "0" (step S110). The background level BGL is updated, for example, by calculating a weighted average of the overall intensity F obtained as a result of the calculation in step S106 and the background level BGL obtained as a result of the calculation in step S109 of the previous knocking determination calculation cycle.

[0081] On the other hand, if the answer is YES in step S108, the MPU 43 determines that knocking has occurred and sets the knock determination flag to "1" (step S111). The knock determination flag in steps S110 and S111 is used in the calculation process (control task) of the ignition timing, which will be described later.

[0082] Next, the operation and effect of the knocking determination by the ECU according to one embodiment of the present invention will be described with reference to Fig. 14. Fig. 14 is a time chart showing an example of the corrected knock window and filter switching timing in the knocking determination by the internal combustion engine control device according to one embodiment of the present invention.

[0083] In Fig. 14, the reference start point Wsb and the reference end point Web of the knock window are preset after the top dead center (TDC) of piston 4 of combustion cylinder #1 and the top dead center (TDC) of combustion cylinder #2. In the time chart shown in Fig. 14, filter B is selected when determining whether there is a knock in the explosion cycle of combustion cylinder #1, and filter A is selected when determining whether there is a knock in the explosion cycle of combustion cylinder #2. This is a time chart showing the correction process for the knock window when switching is performed based on the selection of such filters.

[0084] In determining whether knocking occurs during the explosion cycle of combustion cylinder #1, the start point of the knock window is shifted from the reference start point Wsb to a corrected start point Wsc, which is delayed by +Tb (see map M1 in FIG. 8), in accordance with the response delay characteristics of filter B. Furthermore, if the end point of the knock window were set to a position delayed by +Tb from the reference end point Web, the filter would switch beyond the Ref position, so the end point is shifted from the reference end point Web to a corrected end point Wec, which is corrected to the Ref position (step S307 in the flowchart shown in FIG. 13). The output of filter B is integrated over this corrected integration period.

[0085] In the subsequent knocking determination for the explosion cycle of combustion cylinder #2, similar to the case of filter B, the start point of the knock window is shifted from the reference start point Wsb to a corrected start point Wsc, which is delayed by +Ta (see map M1 in FIG. 8), in accordance with the response delay characteristics of filter A. Meanwhile, unlike the case of filter B, the end point of the knock window is shifted to a corrected end point Wec, which is delayed by +Ta from the reference end point Web, because the end point still precedes the Ref position even when delayed by +Ta from the reference end point Web (step S306 in the flowchart shown in FIG. 13). The output of filter A is integrated over this corrected integration period.

[0086] In this way, in the ECU 40 according to this embodiment, the knock window, which is the integration period for the integral calculation of the filter output, is corrected in accordance with the characteristics (response delay) of the filter used in the filter processing unit 53, thereby reducing erroneous determination of knocking due to the effect of the response delay of the filter.

[0087] Next, the procedure for calculating the ignition timing of the ignition device in the ECU according to one embodiment of the present invention will be described with reference to Fig. 15. Fig. 15 is a flowchart showing an example of the procedure for calculating the ignition timing of the engine in the internal combustion engine control device according to one embodiment of the present invention shown in Fig. 2.

[0088] The ECU 40 adjusts the ignition timing according to the result of the determination of whether or not knocking has occurred. Therefore, by improving the accuracy of the knocking determination, the adjustment of the ignition timing can also be improved. The ECU 40 periodically (for example, every 10 msec) executes the following series of calculations for the ignition timing of the ignition device.

[0089] In FIG. 14, the MPU 43 of the ECU 40 first reads the engine speed N detected by the crank angle sensor 34 and the intake air amount Q detected by the air flow sensor 31 via the RAM 42 (step S401).

[0090] Next, the MPU 43 calculates the basic ignition timing θ from the basic ignition timing map based on the engine speed N and intake air amount Q read in step S401. base Specifically, the intake air amount Q / N (basic fuel injection amount) per unit rotation speed is calculated, and the fuel injection time width Ti is calculated from the intake air amount Q / N per unit rotation speed obtained as a result of the calculation. The basic ignition timing θ is calculated using a basic ignition timing map from the intake air amount Q / N obtained as a result of the calculation and the engine rotation speed N that has been read. base The basic ignition timing map is calculated based on the intake air amount Q / N per unit rotation speed, engine rotation speed N, and basic ignition timing θ base This is a data map that describes the correspondence between the

[0091] Next, the MPU 43 determines whether knocking has occurred (step S403). Specifically, the MPU 43 determines whether knocking has occurred based on a knock flag (the processing result executed according to the flowchart shown in FIG. 11 described above), which is the processing result of the knocking determination. If the knock flag is "1" (YES), that is, if the MPU 43 determines that knocking has occurred, the MPU 43 proceeds to step S412. On the other hand, if the knock flag is "0" (NO), that is, if the MPU 43 determines that knocking has not occurred, the MPU 43 proceeds to step S404.

[0092] If YES in step S403, the MPU 43 calculates the lead angle θ adv to a predetermined retard amount Δθ ret (step S412). This subtraction retards the ignition timing of the ignition device. Next, the MPU 43 initializes a count value A (step S413) and proceeds to step S408. The count value A is a variable for counting the number of times knocking occurs. How the count value A is used will be explained in the steps described later.

[0093] If the answer is NO in step S403, the MPU 43 counts up the count value A by one (step S404) and determines whether the count value A has reached a predetermined value (for example, 50 in FIG. 14) (step S404). If the count value A has reached the predetermined value (YES), the process proceeds to step S406, whereas if it has not reached the predetermined value (NO), the process skips to step S408.

[0094] If YES in step S405, the MPU 43 calculates the lead angle θ adv A predetermined advance angle Δθ adv (step S406). This addition is for recovering the ignition timing that was retarded in step S412. If this flowchart is executed every 10 msec, 0.5 seconds will have passed since count value A was initialized when it reaches 50. In other words, this step S406 recovers the ignition timing every 0.5 seconds that have passed since the ignition timing was retarded in response to the occurrence of knocking. Next, the MPU 43 initializes count value A (step S407), and the process proceeds to step S408.

[0095] In step S408, the MPU 43 calculates the basic ignition timing θ base For lead angle θ adv By adding ign Calculate the following. .

[0096] Next, the MPU 43 calculates the maximum advance value θ from the maximum advance value map based on the engine speed N and the intake air amount Q / N per unit rotation speed obtained in steps S401 and S402. res The maximum advance angle map is calculated based on the relationship between the intake air amount Q / N per unit rotation speed, the engine rotation speed N, and the maximum advance angle θ res This is a data map that describes the correspondence between the

[0097] Next, the MPU 43 calculates the ignition timing θ ignis the maximum advance angle value θ calculated in step S409. res It is determined whether the ignition timing θ ign is the maximum advance angle θ res If it does not exceed (NO), skip. On the other hand, the ignition timing θ ign is the maximum advance angle θ res If it exceeds (YES), the ignition timing θ ign Maximum advance angle value θ res (Step S411). This is because the ignition timing θ ign Maximum advance angle value θ res is limited to In this way, the ECU 40 according to the present embodiment adjusts the ignition timing θ in accordance with the determination result of whether or not knocking has occurred. ign Therefore, by improving the accuracy of determining whether or not knocking has occurred, it becomes possible to appropriately set the ignition timing of the ignition device of the engine 1.

[0098] As described above, the ECU 40 (internal combustion engine control device) according to one embodiment of the present invention includes a processing device 43 that performs processing to determine whether or not knocking has occurred in the engine 1 (internal combustion engine) based on a detection signal from the vibration sensor 35 that detects vibrations of the engine 1 (internal combustion engine), and a storage device 41 that stores information necessary for the determination processing of the processing device 43. The processing device 43 includes a filter processing unit 53 that inputs the detection signal from the vibration sensor 35 to at least one filter to extract vibration components in a specific frequency band, an integration calculation unit 54 that performs an integration calculation based on the output signal from the filter of the filter processing unit 53, a knock determination unit 58 (determination unit) that determines whether or not knocking has occurred in the engine 1 (internal combustion engine) based on the calculation result of the integration calculation unit 54, and a knock window correction unit 52 (period correction unit) that corrects the integration period of the integration calculation unit 54 with respect to a knock window (a preset period) in accordance with the characteristics of the filter.

[0099] According to this configuration, by correcting the integration period of the integration calculation performed by filter output integration calculation unit 54 based on the output signal of the filter of filter processing unit 53 with respect to the knock window (a preset period) in accordance with the characteristics of the filter, it is possible to reduce the effect of the response delay (characteristics) of the filter on the integration period of the integration calculation, thereby suppressing erroneous determination of the presence or absence of knocking based on the calculation result of the integration calculation. In other words, it is possible to improve the accuracy of knock detection when determining the presence or absence of knocking based on the result of inputting the detection signal of vibration sensor 35 to the filter.

[0100] In this embodiment, the filter processing unit 53 has a filter A and a filter B (plurality of filters) having different characteristics. The filter A and the filter B (plurality of filters) are configured to differ in at least one of the center frequency of the frequency band for extracting the vibration component, the width of the frequency band for extracting the vibration component, the filter order, and the filter type.

[0101] According to this configuration, by using a plurality of filters with different characteristics, it is possible to extract vibration components specific to knocking more effectively, thereby reducing erroneous determination of knocking and improving the accuracy of knocking detection.

[0102] In this embodiment, filter processing unit 53 is configured to process the detection signal of vibration sensor 35 using a plurality of filters, and filter output integration calculation unit 54 (integration calculation unit) is configured to perform integration calculation based on the output signals of the plurality of filters. Knock window correction unit 52 (period correction unit) is configured to correct the integration period of integration calculation unit 54 in accordance with the characteristics of each of the plurality of filters.

[0103] According to this configuration, by correcting the integration period of the integration calculation of the output of each filter in accordance with the characteristics of that filter, the effect of the response delay of each filter in the integration calculation of the output of each filter can be reduced, thereby reducing erroneous determination of knocking and improving the accuracy of knocking detection.

[0104] In addition, in this embodiment, the processing device 43 further has the function of a filter switching unit 51 that selects at least one filter from filter A and filter B (multiple filters) of the filter processing unit 53 depending on the operating state of the engine 1 (internal combustion engine) and switches it as the filter that performs the processing of the filter processing unit 53.

[0105] According to this configuration, even if the vibration component specific to knocking changes due to a change in the operating state of the engine 1 (internal combustion engine), erroneous determination of knocking can be reduced by using a filter that corresponds to the change.

[0106] Furthermore, in this embodiment, a correction amount map in which the correction amount of the integration period of integration calculation unit 54 is set for each of filter A and filter B (plurality of filters) in accordance with the characteristics of each of the plurality of filters is stored in advance in storage device 41. Knock window correction unit 52 (period correction unit) of processing device 43 is configured to correct the start point of the integration period of integration calculation unit 54 using the correction amount determined from the correction amount map, and to correct the end point of the integration period of integration calculation unit 54 using either the correction amount determined from the correction amount map or the filter switching timing of filter switching unit 51.

[0107] This configuration makes it possible to prevent the end point of the integration period of the integration calculation unit 54 from occurring after the filter is switched.

[0108] In addition, in this embodiment, the correction amount for each of filter A and filter B (multiple filters) in the correction amount map is set as the delay time of the output of each of filter A and filter B (multiple filters) compared to when there is no filter.

[0109] According to this configuration, the amount of correction for the integration period can be easily set.

[0110] In addition, in this embodiment, the correction amount for each of filter A and filter B (plurality of filters) in the correction amount map is set as the delay time of the output of each of filter A and filter B (plurality of filters) when compared with the output of filter B (a certain reference filter).

[0111] According to this configuration, the amount of correction for the integration period can be easily set.

[0112] [Other embodiments] It should be noted that the present invention is not limited to the present embodiment, and various modifications are included. The above-described embodiment has been described in detail to clearly explain the present invention, and is not necessarily limited to an embodiment including all of the described configurations. It is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0113] For example, in the above-described embodiment, the ECU 40 executes software to execute each step of the knocking determination process. However, it is also possible to implement the steps by implementing hardware such as a circuit device having the same function as the execution of the software. For example, it is also possible to implement any one of the following functional units by a circuit device: a filter that extracts vibration components in a specific frequency band; an integration calculation unit 54 that integrates the filter output; an overall intensity calculation unit 55; a smoothing process 56; a knock indicator calculation unit 57; and a knock determination unit 58.

[0114] In addition, in the embodiment, the ratio (S / N ratio) of the overall intensity to the background level BGL is calculated as the knock index for that frequency component. However, instead of the ratio (S / N ratio) of the overall intensity to the background level BGL, a configuration is also possible in which the difference of the overall intensity from the background level is used as the knock index.

[0115] Furthermore, in the above-described embodiment, an example has been shown in which a correction amount map in which the correction amount of the integration period of integration calculation unit 54 for each of filter A and filter B is set in accordance with the characteristics of each of the multiple filters is stored in advance in storage device 41, and knock window correction unit 52 of processing device 43 corrects the start point of the integration period of integration calculation unit 54 using the correction amount determined from the correction amount map, and corrects the end point of the integration period of integration calculation unit 54 using either the correction amount determined from the correction amount map or the filter switching timing of filter switching unit 51.

[0116] However, it is also possible to configure the system so that a correction amount map is stored in advance in ROM 41 (storage device), in which the correction amount for the integration period of integration calculation unit 54 is set for each of a plurality of filters according to the characteristics of each of the plurality of filters, and knock window correction unit 52 (period correction unit) of processing device 43 uses the correction amount determined from the correction amount map to correct the start point and end point of the integration period of integration calculation unit 54. This configuration is applicable when a plurality of filters are used simultaneously without being switched. [Explanation of symbols]

[0117] 1... engine (internal combustion engine), 35... vibration sensor, 40... ECU (internal combustion engine control unit), 41... ROM (storage device), 43... MPU (processing device), 51... filter switching unit, 52... knock window correction unit (period correction unit), 53... filter processing unit, 54... filter output integral calculation unit (integral calculation unit), 58... knock determination unit (determination unit)

Claims

1. A processing device that performs processing to determine whether or not knocking has occurred in an internal combustion engine based on a detection signal from a vibration sensor that detects vibrations in the internal combustion engine; an internal combustion engine control device including a storage device that stores information necessary for the determination processing of the processing device, The processing device includes: a filter processing unit that inputs the detection signal of the vibration sensor to at least one filter to extract vibration components in a specific frequency band; an integration calculation unit that performs integration calculation based on the output signal from the filter of the filter processing unit; a determination unit that determines whether or not knocking has occurred in the internal combustion engine based on the calculation result of the integral calculation unit; a period correction unit that corrects an integration period of the integration calculation unit with respect to a preset period in accordance with characteristics of the filter, the filtering unit has a plurality of filters having different characteristics; the plurality of filters are configured to differ in at least one of a center frequency of a frequency band for extracting vibration components, a width of the frequency band for extracting vibration components, a filter order, and a filter type; the filter processing unit is configured to process the detection signal of the vibration sensor using the plurality of filters; the integration calculation unit is configured to perform integration calculations based on the output signals of the plurality of filters, respectively; the period correction unit is configured to correct the integration period of the integration calculation unit in accordance with the characteristics of each of the plurality of filters, the storage device pre-stores a correction amount map in which a correction amount for the integration period of the integral calculation unit is set for each of the plurality of filters in accordance with the characteristics of each of the plurality of filters; The period correction unit of the processing device is configured to correct the start point and end point of the integration period of the integration calculation unit using the correction amount determined from the correction amount map. An internal combustion engine control device characterized by:

2. A processing device that performs processing to determine whether or not knocking has occurred in the internal combustion engine based on a detection signal from a vibration sensor that detects vibrations in the internal combustion engine; an internal combustion engine control device including a storage device that stores information necessary for the determination processing of the processing device, The processing device includes: a filter processing unit that inputs the detection signal of the vibration sensor to at least one filter to extract vibration components in a specific frequency band; an integration calculation unit that performs integration calculation based on the output signal from the filter of the filter processing unit; a determination unit that determines whether or not knocking has occurred in the internal combustion engine based on the calculation result of the integral calculation unit; a period correction unit that corrects an integration period of the integration calculation unit with respect to a preset period in accordance with characteristics of the filter, the filtering unit has a plurality of filters having different characteristics; the plurality of filters are configured to differ in at least one of a center frequency of a frequency band for extracting vibration components, a width of the frequency band for extracting vibration components, a filter order, and a filter type; the processing device further includes a function of a filter switching unit that selects at least one filter from the plurality of filters of the filtering unit in accordance with an operating state of the internal combustion engine and switches the filter as the filter that performs processing of the filtering unit, the storage device pre-stores a correction amount map in which a correction amount for the integration period of the integral calculation unit is set for each of the plurality of filters in accordance with the characteristics of each of the plurality of filters; The period correction unit of the processing device is configured to correct a start point of an integration period of the integration calculation unit using a correction amount determined from the correction amount map, and to correct an end point of the integration period of the integration calculation unit using either the correction amount determined from the correction amount map or a filter switching timing of the filter switching unit. An internal combustion engine control device characterized by:

3. 3. The internal combustion engine control device according to claim 1, The correction amount for each of the plurality of filters in the correction amount map is set as a delay time of the output of each of the plurality of filters compared to when there is no filter. An internal combustion engine control device characterized by:

4. 3. The internal combustion engine control device according to claim 1, The correction amount for each of the plurality of filters in the correction amount map is set as a delay time of the output of each of the plurality of filters when compared with the output of a certain reference filter. An internal combustion engine control device characterized by:

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