Internal combustion engine control device

Abstract

To provide an internal combustion engine control device capable of improving knock detectability.SOLUTION: An internal combustion engine control device 100 has: a vibration waveform detecting section 20 for detecting a vibration waveform from a vibration detection signal from a knock sensor 11 and an angle detection signal from a crank angle sensor 9; an injector noise correction value calculating section 21 extracting, from the vibration waveform, a waveform in operation of an injector as a waveform within a predetermined period from an operation timing of the injector 3 and calculating a correction value for removing noise caused by the operation of the injector 3 on the basis of the waveform in operation of the injector; a noise vibration waveform removing section 22 performing a noise removal processing by applying the correction value to a waveform, of the vibration waveform, in the predetermined period from the operation timing of the injector 3; and a determining section 23 for determining whether or not knock occurs in an engine 1 on the basis of the waveform after the removal processing.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an internal combustion engine control device. [Background technology]

[0002] A conventional knocking determination device for an internal combustion engine includes a noise waveform storage unit, a removal unit, and a determination unit. The noise waveform storage unit stores noise vibration waveforms other than knock in advance. The removal unit removes a portion corresponding to the stored noise vibration waveform from the detected vibration waveform. The determination unit determines whether or not knock has occurred based on the waveform after the noise vibration waveform has been removed (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4491376 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional knocking determination devices for internal combustion engines, noise vibration waveforms caused by the operation of components of the internal combustion engine vary depending on individual differences between the components, the installation distance between the knock sensor and the component, etc. Even if a predetermined noise vibration waveform is applied to a vibration waveform on which such varying noise vibration waveforms are superimposed, it is not possible to properly remove the noise.

[0005] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide an internal combustion engine control device that can improve knock detection performance. [Means for solving the problem]

[0006] An internal combustion engine control device according to the present disclosure includes an electronic control device that receives as input a vibration detection signal from a knock sensor that detects vibrations occurring in the internal combustion engine and an angle detection signal from a crank angle sensor that detects the crank angle of the internal combustion engine. The electronic control device includes: a vibration waveform detection unit that detects a vibration waveform of a knock natural frequency component from the vibration detection signal and the angle detection signal; an injector noise correction value calculation unit that extracts, from the vibration waveform, an injector operation waveform that is a waveform within a set period from the operation timing of an injector that injects fuel into the internal combustion engine, and calculates a correction value for removing injector noise, which is vibration noise caused by the operation of the injector, from the vibration waveform; a noise vibration waveform removal unit that performs injector noise removal processing by applying the correction value to waveforms within a set period from the operation timing of the injector, from the vibration waveform; and a determination unit that determines whether knock is occurring in the internal combustion engine, based on the waveform after removal processing. [Effects of the Invention]

[0007] According to the internal combustion engine control device of the present disclosure, knocking can be detected more accurately. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing the configuration of an engine and a device for controlling the engine in a first embodiment. [Figure 2] 1 is a block diagram showing an internal combustion engine control device according to a first embodiment. [Figure 3] 3 is a diagram showing a first example of a vibration waveform detected by the vibration waveform detection unit of FIG. 2. FIG. [Figure 4] 3 is a diagram showing a second example of a vibration waveform detected by the vibration waveform detection unit of FIG. 2. FIG. [Figure 5] 10 is a diagram showing a third example of a vibration waveform detected by the vibration waveform detection unit of FIG. 2. FIG. [Figure 6] 10 is a diagram showing a fourth example of a vibration waveform detected by the vibration waveform detection unit of FIG. 2. FIG. [Figure 7] 3 is a diagram illustrating a first correction value calculation method performed by the injector noise correction value calculation unit in FIG. 2. FIG. [Figure 8] 3 is a diagram illustrating a part of the process performed by an injector noise correction value calculation unit and the removal process performed by a noise vibration waveform removal unit in FIG. 2. [Figure 9] 3 is a diagram illustrating a second correction value calculation method performed by the injector noise correction value calculation unit in FIG. 2. FIG. [Figure 10] 3 is a diagram illustrating a part of the process performed by an injector noise correction value calculation unit and the removal process performed by a noise vibration waveform removal unit in FIG. 2. [Figure 11] 3 is a flowchart showing a main part of the operation of the internal combustion engine control device of FIG. 2. [Figure 12] 1 is a configuration diagram showing a first example of a processing circuit that realizes the microcomputer of the first embodiment. FIG. [Figure 13] FIG. 4 is a configuration diagram showing a second example of a processing circuit that realizes the microcomputer according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings.

[0010] Embodiment 1 FIG. 1 is a diagram showing the configuration of an engine and a device for controlling the engine in the first embodiment.

[0011] 1, engine 1 has a cylinder 1a. Cylinder 1a has a combustion chamber 1b which is provided with an intake valve 1c, an exhaust valve 1d, and a piston 1e. Engine 1 also has a spark plug 2 and an injector 3. Spark plug 2 and injector 3 are provided so as to face the inside of combustion chamber 1b.

[0012] The engine 1 is also connected to an intake passage 4. An electronically controlled throttle 5 is provided in the intake passage 4. The electronically controlled throttle 5 adjusts the amount of intake air into the engine 1.

[0013] The electronically controlled throttle 5 includes a throttle valve 5a, a motor 5b, and a throttle opening sensor 5c. The throttle valve 5a adjusts the amount of intake air into the engine 1. The motor 5b drives the throttle valve 5a. The throttle opening sensor 5c detects the opening of the throttle valve 5a.

[0014] The ECU (Electronic Control Unit) 6 is an electronic control unit that controls the engine 1. The accelerator position sensor 8 detects the amount of operation of the accelerator pedal 7. The ECU 6 acquires an output signal from the accelerator position sensor 8 and sends a control signal to the motor 5b. By sending the control signal to the motor 5b, the ECU 6 controls the throttle valve 5a to an appropriate opening.

[0015] The cam angle sensor 10 detects the cam angle of the intake camshaft 1g. The knock sensor 11 detects the vibration of the engine 1.

[0016] The air cleaner 14 is provided in the intake passage 4. The air cleaner 14 removes dust, dirt, etc. from the air drawn into the intake passage 4. The air flow sensor 12 measures the flow rate of the intake air after removal of dust, dirt, etc.

[0017] Air drawn into the intake passage 4 passes through the electronically controlled throttle 5, surge tank 15, and intake valve 1c and is introduced into the combustion chamber 1b. The intake air introduced into the combustion chamber 1b mixes with fuel injected from the injector 3. This forms an air-fuel mixture. The mixture is ignited by spark discharge from the spark plug 2 and burns.

[0018] The combustion pressure of the air-fuel mixture is transmitted to the piston 1e, causing it to reciprocate. The reciprocating motion of the piston 1e is transmitted to the crankshaft 1f via the connecting rod 1h, and is thereby converted into the rotational motion of the crankshaft 1f.

[0019] The crank angle sensor 9 detects the crank angle that changes with the rotational movement of the crankshaft 1f and outputs the detected crank angle to the ECU 6 as an angle detection signal.

[0020] The air-fuel mixture after combustion becomes exhaust gas and passes through the exhaust valve 1d and the exhaust manifold 16. The exhaust gas is then purified by the catalyst 17 and emitted into the atmosphere.

[0021] The ECU 6 acquires output signals from various sensors (not shown), including an accelerator position sensor 8, a crank angle sensor 9, a cam angle sensor 10, an airflow sensor 12, and a knock sensor 11. Based on the acquired output signals, the ECU 6 determines the ignition timing, the fuel injection amount, and the like. Based on the determined values, the ECU 6 then drives the injector 3 to inject and supply fuel into the combustion chamber 1b. Based on the determined values, the ECU 6 drives the ignition coil 13. This causes a spark to be discharged from the plug gap of the spark plug 2.

[0022] FIG. 2 is a block diagram showing the internal combustion engine control device according to the first embodiment.

[0023] 2, the internal combustion engine control device 100 includes an ECU 6. The ECU 6 also includes an I / F (Interface) circuit 61 and a microcomputer 62.

[0024] Output signals from various sensors are input to the I / F circuit 61. In Fig. 2, a vibration detection signal from the knock sensor 11 and an angle detection signal from the crank angle sensor 9 are input to the I / F circuit 61.

[0025] The I / F circuit 61 has a low-pass filter (LPF) 18. The low-pass filter 18 removes high-frequency components from the vibration detection signal output from the knock sensor 11.

[0026] Furthermore, low-pass filter 18 biases the vibration detection signal so that the vibration component is centered at, for example, 2.5 V. Low-pass filter 18 also performs gain conversion so that the vibration component falls within a range of 0 to 5 V centered at 2.5 V. When the vibration component is small, low-pass filter 18 amplifies the vibration component centered at 2.5 V. When the vibration component is large, low-pass filter 18 reduces the vibration component centered at 2.5 V. Therefore, all vibration components are captured in A / D conversion unit 19 at the subsequent stage.

[0027] The microcomputer 62 has an A / D conversion unit 19, a vibration waveform detection unit 20, an injector noise correction value calculation unit 21, a noise vibration waveform removal unit 22, a determination unit 23, and a control amount calculation unit 24. The determination unit 23 has a knock determination threshold calculation unit 231 and a knock determination unit 232. In the drawings, the injector may be referred to as "INJ."

[0028] The A / D conversion unit 19 A / D converts the vibration detection signal that has passed through the low-pass filter 18, and sends the digital signal to the vibration waveform detection unit 20. The A / D conversion unit 19 performs A / D conversion at regular time intervals, such as 10 μs or 20 μs.

[0029] The A / D conversion unit 19 may always perform A / D conversion and send only the digital signals required for subsequent processing to the vibration waveform detection unit 20. Alternatively, the A / D conversion unit 19 may only A / D convert the vibration detection signals required for subsequent processing and send them to the vibration waveform detection unit 20.

[0030] Vibration waveform detection unit 20 performs frequency analysis using digital signal processing to calculate the vibration waveform of the knock natural frequency component. As digital signal processing, vibration waveform detection unit 20 performs processes such as a discrete Fourier transform (DFT) and a short-time Fourier transform (STFT). Vibration waveform detection unit 20 calculates the spectrum of the knock natural frequency component for each predetermined time or each predetermined crank angle by performing digital signal processing. Hereinafter, the spectrum of the knock natural frequency component will be referred to as vibration intensity. Furthermore, the change in vibration intensity for each time or each crank angle will be referred to as the vibration waveform.

[0031] Vibration waveform detection unit 20 may use filter processing such as an infinite impulse response (IIR) filter or a finite impulse response (FIR) filter as digital signal processing. Vibration waveform detection unit 20 may also perform digital signal processing each time A / D conversion is performed by A / D conversion unit 19. Vibration waveform detection unit 20 may also accumulate data from A / D conversion unit 19 and perform digital signal processing collectively in response to interrupt processing synchronized with the rotation of engine 1.

[0032] Vibrations other than knocking are superimposed as noise on the vibration waveform detected by the vibration waveform detection unit 20. Such vibration noise includes those caused by the operation of components such as the injector 3, intake valve 1c, and exhaust valve 1d. Other examples include vibration noise caused by the operation of the piston 1e and vibration noise caused by the combustion of the air-fuel mixture.

[0033] If these vibration noises are superimposed on the vibration waveform, it will be impossible to accurately determine whether or not knock has occurred in the downstream determination unit 23. For this reason, it is necessary to remove the vibration noises.

[0034] Among the vibration noises, the waveform of noise caused by the operation of the injector 3 in particular changes depending on the engine state, environment, etc. at each point in time, as follows.

[0035] The injector 3 opens and closes a plunger provided in the device itself using electromagnetic force generated by energizing a coil. Mechanical collisions that occur during the opening and closing operations of the plunger cause vibrations.

[0036] A load is applied to the plunger in the closing direction by a spring provided in the injector 3. When the engine 1 is running, the plunger is subjected to the pressure inside the cylinder and the fuel pressure. Therefore, when the pressure inside the cylinder and the fuel pressure change, the impact force when the plunger opens and closes also changes.

[0037] Furthermore, the electromagnetic force generated when current is applied to the coil varies depending on the applied voltage and temperature, so the impact force during opening and closing also varies depending on the voltage and temperature conditions.

[0038] As described above, the waveform of the vibration noise caused by the operation of the injector 3 changes depending on the engine rotation speed, engine load state, ambient temperature, fuel pressure, applied voltage, etc. Therefore, it is necessary to remove the vibration noise caused by the operation of the injector 3 after capturing the current waveform of the vibration noise.

[0039] On the other hand, knocking occurs for a certain period after ignition. Therefore, whether or not knocking has occurred is determined based on the vibration waveform for a certain period after ignition. This period is called the knock window open period.

[0040] If vibration noise is superimposed during this knock window open period, it may be determined that a knock is occurring even though a knock is not actually occurring. In particular, in a multi-cylinder engine with many cylinders, the knock sensor 11 also detects vibration noise from the other cylinders. For this reason, the detection intervals for vibration noise are narrower in a multi-cylinder engine than in a single-cylinder engine, making it easier for vibration noise to be superimposed on the vibration waveform.

[0041] A specific example will be used below for explanation.

[0042] Fig. 3 is a diagram showing a first example of a vibration waveform detected by the vibration waveform detection unit 20 of Fig. 2. Fig. 3 also focuses on the third cylinder of a six-cylinder engine and shows an example of a waveform when vibration noise from the injector of the second cylinder is superimposed. In Fig. 3, a vibration waveform due to knocking is not detected.

[0043] In Figure 3, the horizontal axis represents the crank angle relative to the top dead center (TDC) of the third cylinder. Ignition timing SA is the timing at which ignition starts in the third cylinder. Opening timing SOI is the timing at which the injector starts opening, and opening timing SOI(#2) is the timing at which the injector for the second cylinder starts opening. Closing timing EOI is the timing at which the injector starts closing, and closing timing EOI(#2) is the timing at which the injector for the second cylinder starts closing.

[0044] Furthermore, the knock window open period after the ignition timing SA is the target period for knock detection in the third cylinder.

[0045] Intake valve closing timing IVC(#6) is the timing at which the intake valve of cylinder 6 starts to close, and exhaust valve closing timing EVC(#4) is the timing at which the exhaust valve of cylinder 4 starts to close.

[0046] In Figure 3, vibration noise caused by the operation of the injector of cylinder 2 is superimposed after both the opening operation timing SOI(#2) and the closing operation timing EOI(#2). This vibration noise caused by the operation of the injector is called injector noise.

[0047] In Figure 3, the injector noise of cylinder 2 occurs outside the knock window open period, so there is no erroneous knock detection due to injector noise.

[0048] Additionally, the start of closing of the exhaust valve of cylinder 4 near top dead center (TDC) occurs while the knock window is open. However, the noise level is small, so this does not lead to an erroneous determination. Similarly, the start of closing of the intake valve of cylinder 6 does not need to be taken into consideration because the noise level is also small.

[0049] Fig. 4 is a diagram showing a second example of a vibration waveform detected by vibration waveform detection section 20 of Fig. 2. Fig. 4 is also a diagram showing a vibration waveform when knocking occurs.

[0050] In the case of Figure 4, the injector noise of cylinder 2 is also superimposed on the vibration waveform. However, the injector noise occurs outside the knock window open period. Therefore, in Figure 4, the injector noise does not affect the determination of whether knock is occurring.

[0051] Fig. 5 is a diagram showing a third example of a vibration waveform detected by the vibration waveform detection unit 20 of Fig. 2. In Fig. 5, the injector of the second cylinder performs fuel injection twice for one ignition, unlike Fig. 3. This type of injection mode is called split injection.

[0052] In addition, the opening operation timing SOI1 in Figure 5 is the timing when the injector starts opening for the first injection. The closing operation timing EOI1 is the timing when the injector starts closing for the first injection. The opening operation timing SOI2 is the timing when the injector starts opening for the second injection. The closing operation timing EOI2 is the timing when the injector starts closing for the second injection.

[0053] In Figure 5, the injector noise after the opening timing SOI2 and the injector noise after the closing timing EOI2 overlap within the knock window open period of cylinder 3. This may result in a misjudgment that knock is occurring even when knock is not actually occurring.

[0054] FIG. 6 is a diagram showing a fourth example of a vibration waveform detected by the vibration waveform detection unit 20 of FIG. 2. Like FIG. 5, FIG. 6 shows a vibration waveform in which split injection is performed in the second cylinder and knock is occurring in the third cylinder. In addition to the occurrence of knock, the injector noise after the opening operation timing SOI2 and the injector noise after the closing operation timing EOI2 are superimposed, so the vibration intensity during the knock window open period is higher than in FIG. 5. In this case, the result of the knock threshold determination and the control amount for suppressing knock are affected.

[0055] 2 calculates a correction value for removing such injector noise, and a noise vibration waveform removal unit 22 performs a process of removing the injector noise by applying the calculated correction value.

[0056] The injector noise correction value calculation unit 21 and the noise vibration waveform elimination unit 22 will be described below.

[0057] The injector noise correction value calculation unit 21 calculates a correction value for performing a removal process on the injector noise. This correction value is referred to as the injector noise correction value. The injector noise correction value calculation unit 21 extracts an injector operation waveform, which is a waveform within a set period from the operation timing of the injector 3. This operation timing of the injector 3 may be an opening operation timing or a closing operation timing. The injector noise correction value calculation unit 21 also calculates the injector noise correction value based on the extracted injector operation waveform.

[0058] FIG. 7 is a diagram illustrating a first correction value calculation method performed by the injector noise correction value calculation unit 21 in FIG.

[0059] In Figure 7, the predetermined set period is equivalent to 2 msec. For example, the vibration waveform detection unit 20 performs discrete Fourier transform processing on 72 sample data using values ​​A / D converted at 10 μsec intervals. The vibration waveform detection unit 20 also outputs the calculation results while shifting the target range of the 72 sample data by 1 / 4 sample at a time. In this case, the calculation results of the discrete Fourier transform are output every 180 μsec.

[0060] When the vibration waveform detection unit 20 outputs a vibration waveform under the above conditions, the number of samples that are equal to or greater than 2 msec and close to 2 msec is 12. Therefore, as shown in (1) of FIG. 7, the injector noise correction value calculation unit 21 extracts 12 pieces of sample data from the timing when the injector 3 changes from the closed state to the open state. Then, as shown in (2) of FIG. 7, the injector noise correction value calculation unit 21 stores the extracted 12 pieces of sample data as data for calculating a correction value.

[0061] Next, the numerical conditions for the injector noise correction value will be explained.

[0062] Generally, a knock determination threshold used for knock determination is calculated based on a background level (BGL), which is the vibration intensity when no knock is occurring. If a vibration intensity greater than the knock determination threshold is detected, it is determined that a knock is occurring.

[0063] As will be described later, the correction is performed by subtracting the injector noise correction value from the value detected by the vibration waveform detection unit 20. If the injector noise correction value is excessively large, the vibration intensity after subtracting the injector noise correction value becomes too small. If the vibration intensity becomes too small, the background level and knock determination threshold also become too small, making it difficult to detect knock.

[0064] For this reason, the injector noise correction value calculation unit 21 performs a calculation process on the correction stored value, which is the original waveform, so that the injector noise correction value does not become excessively large. Note that in Fig. 7, the correction stored value is a vibration waveform for 12 samples from the operation timing of the injector 3. Then, the injector noise correction value calculation unit 21 sets the waveform after this calculation process as the injector noise correction value.

[0065] 7, the injector noise correction value calculation unit 21 multiplies the stored correction value by a set value, subtracts the set value from the stored correction value, or performs both multiplication and subtraction. The injector noise correction value calculation unit 21 calculates the injector noise correction value through this calculation process.

[0066] 7(3) is the waveform of the injector noise correction value calculated by multiplication. The injector noise correction value calculation unit 21 calculates the injector noise correction value by multiplying the stored correction value by a set value.

[0067] The solid line waveform in (4) of Figure 7 is the waveform of the injector noise correction value calculated by subtraction. The injector noise correction value calculation unit 21 calculates the injector noise correction value by subtracting a set value from the correction storage value. If the subtraction result is a negative value, the injector noise correction value calculation unit 21 performs lower limit clipping processing so that a predetermined lower limit value, for example, the lower limit value becomes 0. This lower limit value may be a value that takes into account the background level.

[0068] The injector noise correction value calculation unit 21 may calculate the injector noise correction value by performing both calculations, such as subtracting a set value from the correction storage value and then multiplying it by another set value.

[0069] The set value used for multiplication when calculating the injector noise correction value may be a single value. The set value used for subtraction when calculating the injector noise correction value may be a single value.

[0070] Alternatively, the injector noise correction value calculation unit 21 may use map data that associates engine rotation speeds with set values ​​to determine the set values ​​used for multiplication or subtraction. In this case, the injector noise correction value calculation unit 21 derives the set value from the current engine rotation speed using the map data.

[0071] Alternatively, the injector noise correction value calculation unit 21 may use map data that associates engine load states with set values ​​to determine the set values ​​used for multiplication or subtraction. In this case, the injector noise correction value calculation unit 21 derives the set values ​​from the current engine load state using the map data.

[0072] In this way, the injector noise correction value calculation unit 21 multiplies or subtracts the original stored correction value to set the injector noise correction value. This prevents the BGL and knock determination threshold from becoming excessively small. This prevents a situation in which knock determination cannot be performed normally.

[0073] 7 shows a method for calculating the injector noise correction value for the opening operation of the injector 3, but the same applies to the closing operation. That is, the injector noise correction value calculation unit 21 extracts and stores vibration waveforms within a set period for each of the opening operation timing and closing operation timing of the injector 3.

[0074] 8(1) and 8(2) are diagrams showing part of the operation of the injector noise correction value calculation unit 21 during the closing operation of the injector 3. Here, the vibration waveform during the closing operation of the injector 3 is extracted and stored.

[0075] The occurrence of injector noise may differ between the opening operation and the closing operation of the injector 3. In the examples of (1) and (2) in Figure 7, 12 samples after the opening operation of the injector 3 are stored to calculate the injector noise correction value. In contrast, in the examples of (1) and (2) in Figure 8, 14 samples after the closing operation of the injector 3 are stored to calculate the injector noise correction value.

[0076] In this way, the storage times for the opening operation and the closing operation may be the same, or may be different in accordance with the characteristics of the injector 3.

[0077] Thereafter, the injector noise correction value calculation unit 21 performs subtraction or multiplication to calculate the injector noise correction value at the time of the closing operation of the injector 3. The details are the same as those in (3) and (4) of FIG.

[0078] Next, the noise vibration waveform elimination unit 22 will be described. The noise vibration waveform elimination unit 22 subtracts an injector noise correction value from the vibration waveform detected by the vibration waveform detection unit 20. By performing subtraction using the injector noise correction value in this way, the noise vibration waveform elimination unit 22 performs processing to eliminate injector noise and obtains a waveform that is to be used for knock determination. Here, the waveform that is to be used for knock determination after the elimination processing is referred to as a knock vibration waveform.

[0079] (3) and (4) of FIG. 8 are diagrams for explaining the removal process by the noise vibration waveform removal unit 22 of FIG.

[0080] The correction for the waveform after the closing operation is performed using the injector noise correction value calculated based on the waveform after the opening operation. Therefore, the subtraction process is performed using the injector noise correction value only for the 12 samples after the closing operation.

[0081] Figure 8 (3) shows an example of a case where subtraction processing is performed using the injector noise correction value shown in Figure 7 (3). In Figure 8 (3), the dashed line shows the wave waveform shown in Figure 8 (1), and the solid line shows the knock vibration waveform after correction.

[0082] Also, (4) in Fig. 8 is an example of a case where subtraction processing is performed using the injector noise correction value shown in (4) in Fig. 7. In (4) in Fig. 8, the dashed line is the wave waveform shown in (1) in Fig. 8, and the solid line is the knock vibration waveform after correction.

[0083] As will be described later, the peak value is important in determining knock. Although there is a difference in the shape of the corrected waveform between (3) in Figure 8 and (4) in Figure 8, the peak value, which is an important factor, is about the same.

[0084] Next, a process for removing injector noise, which is partially different from the above, will be described.

[0085] Fig. 9 is a diagram illustrating a second correction value calculation method performed by the injector noise correction value calculation unit 21 in Fig. 2. Fig. 9 also shows a method for acquiring the maximum value of a preset sample period as the stored correction value.

[0086] There is a difference in the state of force applied to the plunger during the opening and closing operations of the injector 3. For this reason, the timing at which the peak value of the injector noise occurs may differ between the opening and closing operations.

[0087] Furthermore, even if the opening operation and the closing operation are in the same operational state, the timing at which the peak value of the injector noise occurs may differ depending on the operating state of the vehicle, the timing of the discrete Fourier transform calculation process, and the like.

[0088] To reduce the influence of variations in the timing of these occurrences, the injector noise correction value calculation unit 21 uses the maximum value of a preset sampling period as the stored correction value. Figure 9 (1) and (2) show a method of taking the maximum value of three samplings.

[0089] The method of calculating the injector noise correction value shown in (3) and (4) of FIG. 9 is the same as the multiplication and subtraction method shown in (3) and (4) of FIG.

[0090] (1) and (2) in Fig. 10 show part of the operation of the injector noise correction value calculation unit 21 during the closing operation. The injector noise correction value calculation unit 21 extracts 14 samples after the closing operation of the injector 3. Then, the injector noise correction value calculation unit 21 performs a modification process that adopts the maximum value described with reference to (1) and (2) in Fig. 9. Then, the injector noise correction value calculation unit 21 stores the injector noise correction value after the modification process as a correction storage value.

[0091] (3) and (4) of Fig. 10 are diagrams for explaining a method of removing injector noise by the noise vibration waveform removing unit 22 of Fig. 2. Also, (3) and (4) of Fig. 10 are diagrams showing the removal process of injector noise using the injector noise correction value obtained by the method of Fig. 9.

[0092] In (3) and (4) of FIG. 10, the injector noise is removed by the same method as that described in (3) and (4) of FIG.

[0093] Here, the peak values ​​of the spectrum after removal processing shown in (3) and (4) of Figure 10 are similar to those shown in (3) and (4) of Figure 8. Therefore, even when the second correction value calculation method is used, it is possible to calculate the peak value, which is an important factor in determining knock, to the same extent. In addition, by using the second correction value calculation method, it is possible to reduce the influence of timing variations.

[0094] When the split injections shown in Figures 5 and 6 are performed, the waveforms after the closing operation timing EOI1 and the opening operation timing SOI2 are corrected by the injector noise correction value using the vibration waveform after the opening operation timing SOI1. The waveform after the closing operation timing EOI2 is corrected by the injector noise correction value using the vibration waveform after the closing operation timing EOI1. As shown in Figures 5 and 6, the opening operation timing SOI1 is the timing at which the injector 3 starts opening its first injection, and the closing operation timing EOI1 is the timing at which the injector 3 starts closing its first injection. The opening operation timing SOI2 is the timing at which the injector 3 starts opening its second injection, and the closing operation timing EOI2 is the timing at which the injector 3 starts closing its second injection.

[0095] The same applies to split injection when three or more injections are performed per ignition. That is, the waveforms after the first closing operation timing EOI and the second and subsequent opening operation timings SOI are corrected by the injector noise correction value calculated using the vibration waveform after the first closing operation timing EOI. Also, the waveforms after the second and subsequent closing operation timings EOI are corrected by the injector noise correction value calculated using the vibration waveform after the first closing operation timing EOI.

[0096] Returning to Fig. 2, the following description will be given of the determination unit 23. A knock determination threshold calculation unit 231 of the determination unit 23 calculates a knock determination threshold VTH based on the peak value VP of the knock vibration waveform. The following (Equation 1) to (Equation 4) are used to calculate the knock determination threshold VTH.

[0097] First, the knock determination threshold calculation unit 231 performs a filter process on the peak value VP for each stroke of the engine 1. Then, the knock determination threshold calculation unit 231 calculates a peak average background level VBGL, which is a background level equivalent to the average value of the peak value VP.

[0098] VBGL[n]=KBGL×VBGL[n-1]+(1-KBGL)×VP[n] ...(Formula 1) VBGL[n]: Peak average background level VP[n]: Peak value of knock vibration waveform KBGL: Filter coefficients

[0099] Next, the knock determination threshold calculation unit 231 calculates the variance VVAR and the standard deviation VSGM of the peak value VP. VVAR[n]=KVAR×VVAR[n-1] +(1-KVAR)×(VP[n]-VBGL[n]) 2 ...(Formula 2) VSGM[n]=VVAR[n] 1 / 2 ...(Formula 3) VSGM[n]: Standard deviation of VP VVAR[n]: variance of VP, KVAR: Filter coefficients

[0100] Next, the knock determination threshold calculation unit 231 calculates the knock determination threshold VTH. VTH[n]=VBGL[n]+KTH×VSGM[n] (Formula 4) VTH[n]: Knock detection threshold KTH: Knock determination threshold calculation coefficient

[0101] The knock determination section 232 of the determination section 23 determines whether or not a knock has occurred using the following (Equation 5): Further, the knock determination section 232 outputs a signal according to the knock intensity. VK[n]=(VP[n]-VBGL[n]) / (VTH[n]-VBGL[n]) ...(Formula 5) VK[n]: Knock intensity

[0102] Knock determination unit 232 determines that a knock has occurred if the result of equation 5 is VK[n]>0. On the other hand, knock determination unit 232 determines that a knock has not occurred if the result of equation 5 is VK[n]≦0.

[0103] The control amount calculation unit 24 calculates the delay amount corresponding to the knock intensity using the following (Equation 6) to (Equation 7). First, the control amount calculation unit 24 calculates the delay amount corresponding to the knock intensity for each ignition. ΔθR[n]=max(-VK[n]×KR,θmin) (Formula 6) ΔθR[n]: Retard amount per ignition KR: Retard angle reflection coefficient θmin: Maximum retard amount

[0104] Next, the control amount calculation unit 24 calculates the knock control amount for the ignition timing by accumulating the retard amount for each ignition. If it is determined that knock has not occurred, the control amount calculation unit 24 returns the ignition timing to the advance angle. θR[n]=min(θR[n-1]+ΔθR[n]+KA,θmax) ...(Formula 7) θR[n]: Knock control amount KA[n]: Lead angle return coefficient θmax: Maximum advance angle

[0105] It should be noted that the above (Equation 1) to (Equation 7) are merely examples for explaining the operation of the first embodiment, and the present invention is not limited to these equations.

[0106] FIG. 11 is a flowchart showing the main part of the operation of the internal combustion engine control device 100 of FIG.

[0107] In step S101, vibration waveform detection unit 20 detects a vibration waveform based on the vibration detection signal from knock sensor 11 and the angle detection signal from crank angle sensor 9.

[0108] The vibration waveform is detected so as to include at least a knock detection interval and an injector noise vibration waveform calculation interval. Here, the knock detection interval is an interval that includes the above-mentioned knock window open period, for example, an interval from top dead center TDC to 60 [deg. ATDC] (ATDC: After Top Dead Center). The injector noise vibration waveform calculation interval is a crank angle interval that is experimentally determined in advance based on the crank angle, for example, from -60 [deg. ATDC] to 60 [deg. ATDC].

[0109] In step S102, the injector noise correction value calculation unit 21 extracts and stores the injector operating waveform, which is a waveform within a set period from the timing of the operation of the injector 3.

[0110] Here, in step S102, the injector noise correction value calculation unit 21 may use the second method shown in (1) and (2) of Fig. 9. In this case, the injector noise correction value calculation unit 21 performs a transformation process on the extracted injector operation waveform. This transformation process is a process of performing a target waveform extraction process and a replacement process.

[0111] The waveform of interest extraction process is a process of extracting a waveform included within a period of the design sample number as a waveform of interest from the extracted injector operating waveform. The design sample number is a number of samples designed in advance. In the examples of (1) and (2) in Figure 9, the design sample number is three. The period of the design sample number is a period including three samples.

[0112] The replacement process is a process of replacing the maximum value in the waveform of interest with the value of the transformed waveform during injector operation.

[0113] As a modification process, the injector noise correction value calculation unit 21 repeatedly performs the target waveform extraction process and the replacement process while sliding the period of the design sample number.

[0114] In step 103, the injector noise correction value calculation unit 21 multiplies or subtracts a predetermined set value from the extracted vibration waveform, or performs both. As a result, the noise vibration waveform elimination unit 22 calculates the injector noise correction value.

[0115] In step S104, if injector noise is superimposed on the knock detection section, the noise vibration waveform elimination unit 22 performs processing to eliminate the injector noise, thereby obtaining a knock vibration waveform.

[0116] In step S105, the noise vibration waveform elimination unit 22 calculates a peak value VP of the knock vibration waveform in the knock detection section.

[0117] In step S106, the knock determination threshold calculation unit 231 calculates the knock determination threshold VTH based on the peak value VP.

[0118] In step S107, knock determination unit 232 determines whether a knock has occurred based on peak value VP and knock determination threshold VTH. If knock determination unit 232 determines that a knock has occurred, it proceeds to step S108. If knock determination unit 232 determines that a knock has not occurred, it proceeds to step S109.

[0119] The control amount calculation unit 24 retards the ignition timing in step S108, and advances the ignition timing in step S109.

[0120] As described above, the vibration noise caused by the operation of the injector 3 is affected by the fuel pressure applied to the injector 3, the power supply voltage, the injector temperature, etc. For this reason, even if a correction value is prepared in advance and applied to the injector noise caused by the operation of the injector 3, the noise cannot be adequately removed.

[0121] In contrast to this, the internal combustion engine control device 100 in the first embodiment can correct injector noise that occurs thereafter based on injector noise that occurs when the injector 3 opens or closes during operation. This makes it possible to perform injector noise removal processing with high accuracy without being affected by various operating conditions.

[0122] Injector noise correction is required when a change in the injector operating state occurs while the knock window is open. In particular, in the operating range where the engine speed is low, the background level is relatively low, so the impact of injector noise is significant. Therefore, injector noise removal processing may be performed only when the engine speed or engine load is low. This reduces the processing load of the program. In this case, in FIG. 11, steps S102 to S104 are performed only when either the engine speed or the engine load is within a predetermined range.

[0123] In the first embodiment, the injector noise correction value calculation unit 21 extracts, from the vibration waveform, an injector operating waveform that is a waveform within a set period from the timing of operation of the injector 3. The injector noise correction value calculation unit 21 also calculates an injector noise correction value based on the extracted injector operating waveform. The noise vibration waveform elimination unit 22 performs an injector noise elimination process by applying the injector noise correction value to a waveform within a set period from the timing of operation of the injector 3, from the vibration waveform. The determination unit 23 also determines whether or not knocking has occurred in the engine 1, based on the waveform after the elimination process. This improves the detectability of knocking.

[0124] Furthermore, the injector noise correction value calculation unit 21 performs a transformation process on the extracted injector operating waveform and calculates a correction value based on the transformed injector operating waveform. As part of this transformation process, the injector noise correction value calculation unit 21 repeatedly performs a target waveform extraction process and a replacement process while sliding the period of the design sample number. This makes it possible to reduce the influence of timing variations without impairing the peak value, which is an important factor in determining knock.

[0125] Furthermore, the injector noise correction value calculation unit 21 calculates the injector noise correction value by multiplying the injector operating waveform by a set value, by subtracting the set value, or by performing both multiplication and subtraction. This makes it possible to avoid a state in which knock determination cannot be performed normally.

[0126] Furthermore, the injector noise correction value calculation unit 21 uses, as a set value for multiplication or subtraction, a value determined in advance based on either the rotation speed or the load state of the engine 1. This makes it possible to obtain an injector noise correction value that matches the state of the engine 1 at each point in time.

[0127] Furthermore, if the result of applying the injector noise correction value is a negative value, the noise vibration waveform elimination unit 22 performs lower limit clipping processing so that the result becomes a preset lower limit value. This makes it possible to prevent the result of applying the injector noise correction value from falling outside the set range.

[0128] Furthermore, when the injector 3 performs one fuel injection per ignition, the injector noise correction value calculation unit 21 extracts an injector operation waveform when the injector 3 is opening. The injector noise correction value calculation unit 21 calculates an injector noise correction value as an opening operation correction value based on the extracted injector operation waveform. The noise vibration waveform elimination unit 22 then applies the opening operation correction value to the waveform when the injector is closing. This makes it possible to generate an injector noise correction value that is suited to the current environment and to apply the injector noise correction value immediately.

[0129] Furthermore, when the injector 3 performs multiple fuel injections per ignition, the injector noise correction value calculation unit 21 extracts the injector operation waveform during the first opening operation of the injector 3. The injector noise correction value calculation unit 21 calculates the injector noise correction value as the opening operation correction value based on the extracted injector operation waveform. The noise vibration waveform removal unit 22 applies the opening operation correction value to the waveform during the second or subsequent opening operations of the injector 3.

[0130] Therefore, even when the injector 3 performs multiple fuel injections for one ignition, an injector noise correction value that is suited to the current environment can be generated and applied immediately.

[0131] Furthermore, the injector noise correction value calculation unit 21 and the noise vibration waveform elimination unit 22 operate only when either the rotation speed or the load state of the internal combustion engine is within a predetermined range, thereby reducing the processing load of the program.

[0132] Each function of the microcomputer 62 of the first embodiment is realized by a processing circuit. Fig. 12 is a configuration diagram showing a first example of the processing circuit that realizes each function of the microcomputer 62 of the first embodiment. The processing circuit 150 of the first example is dedicated hardware.

[0133] The processing circuit 150 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. Each function of the microcomputer 62 may be realized by a separate processing circuit 150. Alternatively, all functions of the microcomputer 62 may be realized by the processing circuit 150.

[0134] 13 is a diagram showing a second example of a processing circuit that realizes each function of the microcomputer 62 according to the first embodiment. The processing circuit 160 of the second example includes a processor 161 and a memory 162.

[0135] In the processing circuit 160, each function of the microcomputer 62 is realized by software, firmware, or a combination of software and firmware. The software and firmware are written as programs. The software and firmware are stored in the memory 162. The processor 161 realizes the function of each unit by reading and executing the programs stored in the memory 162.

[0136] It can be said that the programs stored in memory 162 cause the computer to execute the procedures or methods of the above-mentioned sections. Here, memory 162 corresponds to non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable and Programmable Read Only Memory), etc. Also, magnetic disks, flexible disks, optical disks, compact disks, minidisks, DVDs, etc. correspond to memory 162.

[0137] The functions of the above-described units may be partially realized by dedicated hardware and partially realized by software or firmware.

[0138] In this way, the processing circuit can realize the functions of each of the above-mentioned units by hardware, software, firmware, or a combination of these.

[0139] Although the embodiments have been described in detail above, the present invention is not limited to the embodiments, and various modifications and substitutions can be made thereto.

[0140] Below, aspects of the present disclosure are summarized as appendices. (Appendix 1) an electronic control device to which a vibration detection signal from a knock sensor that detects vibrations occurring in the internal combustion engine and an angle detection signal from a crank angle sensor that detects a crank angle of the internal combustion engine are input, The electronic control device a vibration waveform detection unit that detects a vibration waveform of a knock natural frequency component from the vibration detection signal and the angle detection signal; an injector noise correction value calculation unit that extracts an injector operating waveform from the vibration waveform, which is a waveform within a set period from the timing of operation of an injector that injects fuel into the internal combustion engine, and calculates a correction value based on the extracted injector operating waveform to remove injector noise, which is vibration noise caused by the operation of the injector, from the vibration waveform; a noise vibration waveform elimination unit that applies the correction value to a waveform within the set period from the timing of the operation of the injector, among the vibration waveforms, to perform a process of eliminating the injector noise; a determination unit that determines whether knocking is occurring in the internal combustion engine based on the waveform after the removal process; An internal combustion engine control device comprising: (Appendix 2) the injector noise correction value calculation unit performs a transformation process on the extracted injector operation waveform, and calculates the correction value based on the injector operation waveform after the transformation process; 2. The internal combustion engine control device according to claim 1, wherein the modification process is a process of repeatedly performing a waveform-of-interest extraction process of extracting a waveform included within a period of a design sample number from the extracted injector operation waveform as a waveform of interest, and a replacement process of replacing the maximum value within the waveform of interest with the value of the modified injector operation waveform, while sliding the period of the design sample number. (Appendix 3) 3. The internal combustion engine control device according to claim 1, wherein the injector noise correction value calculation unit calculates the correction value by multiplying the injector operation waveform by a set value, subtracting a set value from the injector operation waveform, or performing both the multiplication and the subtraction. (Appendix 4) 4. The internal combustion engine control device according to claim 3, wherein the injector noise correction value calculation unit uses a value determined in advance based on either a rotation speed or a load state of the internal combustion engine as the set value for multiplication or subtraction. (Appendix 5) 5. The internal combustion engine control device according to claim 1, wherein, when a result of applying the correction value becomes a negative value, the noise vibration waveform elimination unit performs lower limit clipping processing so that the result becomes a preset lower limit value. (Appendix 6) When the injector injects fuel once for each ignition, the injector noise correction value calculation unit extracts the injector operation waveform during an opening operation of the injector, and calculates the correction value as an opening operation correction value based on the extracted injector operation waveform; 6. The internal combustion engine control device according to claim 1, wherein the noise vibration waveform elimination unit applies the opening operation correction value to a waveform during a closing operation of the injector. (Appendix 7) When the injector injects fuel multiple times for one ignition, the injector noise correction value calculation unit extracts the injector operation waveform during a first opening operation of the injector, and calculates the correction value as an opening operation correction value based on the extracted injector operation waveform; the noise vibration waveform elimination unit applies the opening operation correction value to a waveform at the second or subsequent opening operation of the injector; the injector noise correction value calculation unit extracts the injector operation waveform during a first closing operation of the injector, and calculates the correction value as a closing operation correction value based on the extracted injector operation waveform; 6. The internal combustion engine control device according to claim 1, wherein the noise vibration waveform elimination unit applies the closing operation correction value to a waveform at the time of a second or subsequent closing operation of the injector. (Appendix 8) 8. The internal combustion engine control device according to claim 1, wherein the injector noise correction value calculation unit and the noise vibration waveform elimination unit operate only when either a rotation speed or a load state of the internal combustion engine is within a predetermined range. [Explanation of symbols]

[0141] 1 engine, 6 ECU (electronic control unit), 9 crank angle sensor, 11 knock sensor, 20 vibration waveform detection unit, 21 injector noise correction value calculation unit, 22 noise vibration waveform removal unit, 23 determination unit, 100 internal combustion engine control unit.

Claims

1. an electronic control device to which a vibration detection signal from a knock sensor that detects vibrations occurring in the internal combustion engine and an angle detection signal from a crank angle sensor that detects a crank angle of the internal combustion engine are input, The electronic control device a vibration waveform detection unit that detects a vibration waveform of a knock natural frequency component from the vibration detection signal and the angle detection signal; an injector noise correction value calculation unit that extracts an injector operating waveform from the vibration waveform, which is a waveform within a set period from the timing of operation of an injector that injects fuel into the internal combustion engine, and calculates a correction value based on the extracted injector operating waveform to remove injector noise, which is vibration noise caused by the operation of the injector, from the vibration waveform; a noise vibration waveform elimination unit that applies the correction value to a waveform within the set period from the timing of the operation of the injector, among the vibration waveforms, to perform a process of eliminating the injector noise; a determination unit that determines whether knocking is occurring in the internal combustion engine based on the waveform after the removal process; It has the injector noise correction value calculation unit performs a transformation process on the extracted injector operation waveform, and calculates the correction value based on the injector operation waveform after the transformation process; The transformation process is a process of repeatedly performing a waveform-of-interest extraction process of extracting a waveform included within a period of a design sample number from the extracted injector operation waveform as a waveform of interest, and a replacement process of replacing the maximum value within the waveform of interest with the value of the transformed injector operation waveform, while sliding the period of the design sample number.

2. 2. The internal combustion engine control device according to claim 1, wherein the injector noise correction value calculation unit calculates the correction value by multiplying the injector operating waveform by a set value, subtracting a set value from the injector operating waveform, or performing both the multiplication and the subtraction.

3. 3. The internal combustion engine control device according to claim 2, wherein the injector noise correction value calculation unit uses a value determined in advance based on either a rotation speed or a load state of the internal combustion engine as the set value for multiplication or subtraction.

4. 2. The internal combustion engine control device according to claim 1, wherein, when a result of applying the correction value is a negative value, the noise vibration waveform elimination unit performs lower limit clipping processing so that the result becomes a preset lower limit value.

5. An internal combustion engine control device as described in claim 1, wherein the injector noise correction value calculation unit and the noise vibration waveform removal unit operate only when either the rotational speed or load condition of the internal combustion engine is within a predetermined range.

6. An electronic control device is provided to which a vibration detection signal from a knock sensor that detects vibrations occurring in an internal combustion engine and an angle detection signal from a crank angle sensor that detects a crank angle of the internal combustion engine are input, The electronic control device a vibration waveform detection unit that detects a vibration waveform of a knock natural frequency component from the vibration detection signal and the angle detection signal; an injector noise correction value calculation unit that extracts an injector operating waveform from the vibration waveform, which is a waveform within a set period from the timing of operation of an injector that injects fuel into the internal combustion engine, and calculates a correction value based on the extracted injector operating waveform to remove injector noise, which is vibration noise caused by the operation of the injector, from the vibration waveform; a noise vibration waveform elimination unit that applies the correction value to a waveform within the set period from the timing of the operation of the injector, among the vibration waveforms, to perform a process of eliminating the injector noise; a determination unit that determines whether knocking is occurring in the internal combustion engine based on the waveform after the removal process; It has When the injector injects fuel once for each ignition, the injector noise correction value calculation unit extracts the injector operation waveform during an opening operation of the injector, and calculates the correction value as an opening operation correction value based on the extracted injector operation waveform; The noise vibration waveform elimination unit applies the opening operation correction value to a waveform during a closing operation of the injector.

7. An electronic control device is provided to which a vibration detection signal from a knock sensor that detects vibrations occurring in an internal combustion engine and an angle detection signal from a crank angle sensor that detects a crank angle of the internal combustion engine are input, The electronic control device a vibration waveform detection unit that detects a vibration waveform of a knock natural frequency component from the vibration detection signal and the angle detection signal; an injector noise correction value calculation unit that extracts an injector operating waveform from the vibration waveform, which is a waveform within a set period from the timing of operation of an injector that injects fuel into the internal combustion engine, and calculates a correction value based on the extracted injector operating waveform to remove injector noise, which is vibration noise caused by the operation of the injector, from the vibration waveform; a noise vibration waveform elimination unit that applies the correction value to a waveform within the set period from the timing of the operation of the injector, among the vibration waveforms, to perform a process of eliminating the injector noise; a determination unit that determines whether knocking is occurring in the internal combustion engine based on the waveform after the removal process; It has When the injector performs multiple fuel injections for one ignition, the injector noise correction value calculation unit extracts the injector operation waveform during a first opening operation of the injector, and calculates the correction value as an opening operation correction value based on the extracted injector operation waveform; the noise vibration waveform elimination unit applies the opening operation correction value to a waveform at the second or subsequent opening operation of the injector; the injector noise correction value calculation unit extracts the injector operation waveform during a first closing operation of the injector, and calculates the correction value as a closing operation correction value based on the extracted injector operation waveform; The noise vibration waveform elimination unit applies the closing operation correction value to a waveform at the second or subsequent closing operations of the injector.

8. The injector noise correction value calculation unit performs a transformation process on the extracted injector operating waveform, and calculates the correction value based on the injector operating waveform after the transformation process; 8. The internal combustion engine control device according to claim 6, wherein the modification process is a process of repeatedly performing a waveform-of-interest extraction process of extracting a waveform included within a period of a design sample number from the extracted injector operation waveform as a waveform of interest, and a replacement process of replacing the waveform of interest with a maximum value within the waveform of interest as the value of the modified injector operation waveform, while sliding the period of the design sample number.

Images