WO2017002773A1

WO2017002773A1 - Knocking determination device and knocking determination method

Info

Publication number: WO2017002773A1
Application number: PCT/JP2016/069058
Authority: WO
Inventors: 太郎笠原; 政祥大▲高▼; 優志村; 克行末吉; 太一池田; 莉紗 ▲高▼橋; 道夫村瀬; 志強翁
Original assignee: 株式会社小野測器
Priority date: 2015-06-29
Filing date: 2016-06-28
Publication date: 2017-01-05

Abstract

Provided is a knocking determination device that determines the presence or absence of knocking. The knocking determination device is provided with: a determination signal selecting unit that selects a determination signal from among obtained signals; a target signal selecting unit that selects a plurality of target signals from among the obtained signals; and a determination unit that determines whether the determination signal is a signal that represents knocking. The determination unit is configured so as to: estimate a statistical parameter from values based on the spectra of the plurality of target signals; obtain normalized values by normalizing values based on the spectra of the target signals using the statistical parameter for variations in multiple dimensions of the same values; obtain a normalized value by normalizing a value based on the spectrum of the determination signal using the statistical parameter for variations in multiple dimensions; and determine that the determination signal is a signal that represents knocking on the basis of the degree of separation being large between the set of the normalized values for the plurality of target signals and the normalized value for the determination signal.

Description

Knocking determination apparatus and knocking determination method

The present invention relates to a knocking determination device that determines knocking that occurs in an internal combustion engine, and a knocking determination method.

Generally, the ignition timing in an internal combustion engine such as a gasoline engine is advanced as much as possible within a range of crank angles where knocking does not occur, in order to improve output torque. Therefore, in the process of adapting the ignition timing to the crank angle in the process of designing or adjusting the engine, it is determined by the knocking determination device whether knocking is occurring or not. An example of such a knocking determination device is described in Patent Document 1.

The knocking determination device described in Patent Document 1 calculates a cross-correlation value between an output signal from a pressure sensor that detects an in-cylinder pressure and an output signal from a microphone that detects a sound emitted by an engine, and knocks the cross-correlation value. We handle as strength of.

JP 2003-314349 A

According to the knocking determination device described in Patent Document 1, it is possible to determine the presence or absence of knocking without the person separately hearing the knocking sound. However, in the knocking determination device described in Patent Document 1, the magnitude of the knocking noise and the background noise, which differ depending on the operating conditions of the internal combustion engine such as the change in rotational speed, lowers the determination accuracy as to whether knocking occurs or not. There is a fear. Therefore, it is desirable for the above-described knocking determination device to be able to suitably perform knocking determination under various conditions.

An object of the present invention is to provide a knocking determination device and a knocking determination method capable of suitably performing a knocking determination under various conditions.

A knocking determination device that solves the above problems determines the presence or absence of knocking on the basis of an acquisition signal indicating a physical quantity based on a pressure fluctuation generated in an internal combustion engine, and selects a determination signal for determining the presence or absence of knocking from the acquisition signal. A target signal selection unit for selecting a plurality of target signals based on a condition determined from the acquired signal based on the relationship with the determination signal, and calculating values based on the spectra of the plurality of target signals A second calculation unit that calculates a value based on the spectrum of the determination signal; and a determination unit that determines whether the determination signal is a signal indicating knocking, the determination unit Estimating statistical parameters from values based on the spectra of the plurality of target signals, and using the statistical parameters to estimate values based on the spectra of the respective target signals Normalize with multi-dimensional variations of values to obtain normalized values, and using the statistical parameters, normalize values based on the spectrum of the determination signal with multi-dimensional variations to obtain normalized values, It is determined that the determination signal is a signal indicating knocking based on the fact that the degree of divergence between a set of normalized values for a plurality of target signals and the normalized value of the determination signal is large. Configured

A knocking determination device that solves the above problems determines the presence or absence of knocking on the basis of an acquisition signal indicating a physical quantity based on a pressure fluctuation generated in an internal combustion engine, and selects a determination signal for determining the presence or absence of knocking from the acquisition signal. A target signal selector for selecting a target signal based on a condition determined from the acquired signal in relation to the determination signal; and a calculator for calculating a value based on a spectrum of the determination signal; A determination unit configured to determine whether the determination signal is a signal indicating knocking; and an update unit configured to update a statistical parameter based on a value based on a spectrum of the target signal, the determination unit including the statistic A value based on the spectrum of the determination signal is normalized with variations in multiple dimensions using parameters to obtain a normalized value, and a predetermined determination value Configured to determine that the determination signal based on the degree of divergence between the values after the normalization is large is a signal indicating the knocking.

The knocking determination method for solving the above problems is executed by a knocking determination device that determines the presence or absence of knocking based on an acquired signal indicating a physical quantity based on a pressure fluctuation generated in an internal combustion engine, and the knocking determination device determines from the acquired signal Selecting a determination signal for determining the presence or absence of knocking, selecting the plurality of target signals from the acquired signal based on a condition determined in relation to the determination signal, the knocking determination device, and the knocking determination device. The determination apparatus calculates values based on the spectra of the plurality of target signals, the knocking determination apparatus calculates values based on the spectrum of the determination signal, and the knocking determination apparatus determines the determination signal. Performing a determination as to whether or not the signal is indicative of knocking, the determining comprising: Estimating a statistical parameter from values based on the spectra of a plurality of target signals, normalizing the values based on the spectra of the respective target signals with variations in the same multidimensional value using the statistical parameters and calculating the normalized values Obtaining, using the statistical parameter, normalizing the value based on the spectrum of the determination signal with variations in multiple dimensions to obtain a normalized value, and the normalized value of the plurality of target signals It includes determining that the determination signal is a signal indicating knocking based on the fact that the degree of divergence between the set and the normalized value of the determination signal is large.

The block diagram which shows an example of a connection aspect with various apparatuses when a knocking determination apparatus measures knocking of an engine about 1st Embodiment which actualized the knocking determination apparatus. The block diagram which shows schematic structure of the knocking determination apparatus of embodiment of FIG. The schematic diagram shown about the outline of the acquisition signal processed by the knocking determination apparatus of embodiment of FIG. 1, an object signal, and the determination signal. The flowchart which shows each processing process in order of implementation about the data collection process which the knocking determination apparatus of embodiment of FIG. 1 performs. The flowchart which shows each processing process in order of implementation about the determination value calculation process which the knocking determination apparatus of embodiment of FIG. 1 performs. The flowchart which shows each processing process in order of implementation about the determination processing which the knocking determination apparatus of embodiment of FIG. 1 performs. The schematic diagram which shows typically the outline about the update about the information which the knocking determination apparatus of embodiment of FIG. 1 performs. The flowchart which shows each processing process in order of implementation about the learning process of the object signal which the knocking determination apparatus of embodiment of FIG. 1 performs. The block diagram which shows schematic structure of a knocking determination apparatus about 2nd Embodiment which actualized the knocking determination apparatus. FIG. 10 is a schematic view showing an outline of a determination signal to be processed by the knocking determination apparatus of the embodiment of FIG. 9 and an advance signal; The flowchart which shows each processing process in order of implementation about the data collection process which the knocking determination apparatus of embodiment of FIG. 9 performs. The flowchart which shows each processing process in order of implementation about the determination value calculation process which the knocking determination apparatus of embodiment of FIG. 9 performs. The flowchart which shows each processing process in order of implementation about the determination processing which the knocking determination apparatus of embodiment of FIG. 9 performs. The schematic diagram shown about the outline about the update of the information which the knocking determination apparatus of embodiment of FIG. 9 performs. The flowchart which shows each processing process in order of implementation about the learning process of the prior signal which the knocking determination apparatus of embodiment of FIG. 9 performs. The block diagram which shows schematic structure of a knocking determination apparatus about 3rd Embodiment which actualized the knocking determination apparatus. The flowchart which shows each processing process in order of implementation about the determination value calculation process which the knocking determination apparatus of embodiment of FIG. 16 performs. The flowchart which shows each processing process in order of implementation about the determination processing which the knocking determination apparatus of embodiment of FIG. 16 performs. The block diagram which shows schematic structure of a knocking determination apparatus about 4th Embodiment which actualized the knocking determination apparatus. FIG. 20 is a schematic view showing an outline of update of information performed by the knocking determination device of the embodiment of FIG. 19; The flowchart which shows each processing process in order of implementation about the update process of the statistical parameter which the knocking determination apparatus of embodiment of FIG. 19 performs. The block diagram which shows the example by which the spectrum is hold | maintained at the memory | storage part of the knocking determination apparatus about other embodiment which materialized the knocking determination apparatus. The flowchart which shows each processing process in order of implementation about the determination value calculation process which the knocking determination apparatus of embodiment of FIG. 22 performs. FIG. 23 is a schematic view showing an outline of an acquisition signal, an object signal, a determination signal, and a rejection signal processed by the knocking determination device of the embodiment of FIG. 22; (A) is a figure which shows typically the relationship of a target signal and a determination signal about other embodiment of a knocking determination apparatus, Comprising: The figure which shows about the case where a target signal is temporally after a determination signal, b) is a figure which shows typically the relationship of a target signal and a determination signal about the further another embodiment of a knocking determination apparatus, and is a figure shown about the case where a target signal has time back and front with respect to a determination signal. The block diagram which shows schematic structure which acquires the signal which shows the in-pipe pressure of an engine, and the physical quantity of acceleration about the further another embodiment which materialized the knocking determination apparatus. The block diagram which shows schematic structure of a knocking determination apparatus about further another embodiment which materialized the knocking determination apparatus.

First Embodiment
Hereinafter, a first embodiment of the knocking determination device and the knocking determination method will be described with reference to FIGS. 1 to 8. In the test of the engine 1 for a vehicle, which is an example of an internal combustion engine, a test such as adjustment of the advance amount of ignition timing or a confirmation test of the adjusted ignition timing is performed. A knocking determination device is used in these tests of ignition timing, and the knocking determination method is implemented by the knocking determination device.

As shown in FIG. 1, the engine 1 to be tested is mounted on a vehicle 3. In addition, the engine 1 of test object may be used in the state which is not mounted in the vehicle 3, for example, a single state. An engine ECU 2 that controls driving of the engine 1 is connected to the engine 1. The engine ECU 2 is an engine control unit, and includes a CPU, a ROM, a RAM, other storage devices, and the like. The engine ECU 2 controls the drive of the engine 1 while acquiring various information necessary for the drive control of the engine 1 from the outside of the engine ECU 2 by performing arithmetic processing on programs stored in the ROM and other storage devices by the CPU. . The engine ECU 2 has, as an operating condition under which the engine 1 is in test operation, a normal operating condition under which knocking does not occur in the engine 1 and a test operating condition under which the engine 1 is operating. There is. In the present embodiment, the engine 1 is operated under test operation conditions. Here, knocking is a phenomenon in which a pressure fluctuation (shock wave) caused by abnormal combustion generated in a cylinder of the engine 1 is amplified by the natural frequency of the cylinder and a large vibration occurs in the engine 1. That is, vibration based on pressure fluctuation generated at the time of fuel combustion in the cylinder occurs in the engine 1, and this vibration can be acquired as a physical quantity.

A sound pressure sensor 4 is installed near the engine 1. The sound pressure sensor 4 detects a sound generated from the engine 1 and outputs a sound pressure signal based on the detected sound to the data acquisition device 5. More specifically, the sound pressure sensor 4 detects a sound pressure which is an example of a physical quantity based on a pressure fluctuation generated in the engine 1 and generates a sound pressure signal indicating the magnitude of the detected sound pressure. Therefore, when the engine 1 is not knocking, the sound pressure signal output from the sound pressure sensor 4 does not include the sound generated based on the knocking. On the other hand, when knocking is occurring in the engine 1, the sound pressure signal output from the sound pressure sensor 4 is a sound generated based on the knocking, and the sound having a correlation with the knocking is included.

In addition, the engine ECU 2 outputs angle information indicating the current rotation angle of the engine 1 to the data acquisition device 5. The angle information includes, for example, a rotation pulse and a crank angle pulse. The rotation pulse is a signal that is output at an angle at which the rotation angle of the crankshaft is defined as the origin, and for example, one pulse is output each time the crankshaft rotates once. The crank angle pulse is a signal that is output each time the rotation angle of the crankshaft advances by a unit angle, and for example, when one pulse is output every one degree, four steps of suction, compression, combustion and exhaust are In a four-stroke engine, which is a cycle, 720 pulses are output during two rotations of the crankshaft during one cycle. If the angle information is output to the data acquisition device 5, the angle from the origin sensor that detects the origin of the rotational angle of the crankshaft without passing through the engine ECU 2 or the angle sensor that detects the rotational angle of the crankshaft Information may be output to the data collection device 5.

The data acquisition device 5 receives the sound pressure signal from the sound pressure sensor 4 and performs A / D conversion. Further, the data acquisition device 5 acquires current angle information from the engine ECU 2 at the timing when the sound pressure signal is input. Then, the data acquisition device 5 acquires a sound pressure signal for one cycle of the engine 1 based on the angle information, and uses this as an acquisition signal. Therefore, the data acquisition device 5 generates 1500 acquisition signals per minute if the rotational speed is 3000 r / min and the number corresponds to the rotational speed of the engine 1 per unit time. In addition, angular information acquired together with each sound pressure signal is associated with some or all of the acquired signals. Then, the data acquisition device 5 outputs the acquisition signal associated with the angle information to the knocking determination device 10. Note that the data collection device 5 may temporarily hold the generated acquisition signal or temporarily store it, and then output it to the knocking determination device 10. In addition, the data collection device 5 may associate time information with the acquired signal.

As shown in FIG. 3, assuming that “unit time / rotational speed of engine 1” is a sampling interval d, the data collection device 5 generates “predetermined period / sampling interval d” number of acquisition signals in a predetermined period. Do. For example, when the number of data required for the knocking determination process to be performed later is m, the predetermined period required for the data collection device 5 to generate the required number m of data is “sampling interval d × required number m”. It is calculated.

As shown in FIG. 1, the knocking determination device 10 receives an acquisition signal and angle information from the data acquisition device 5. The knocking determination device 10 executes an operation for determining whether the determination signal is a signal indicating knocking or not based on the target signal selected from the acquisition signal and the determination signal selected from the acquisition signal, and the calculation result Is output to the monitor 6 or the like.

Next, the knocking determination device 10 will be described.
As shown in FIG. 2, the knocking determination device 10 is configured of a CPU, a ROM, a RAM, other storage devices, and the like. The knocking determination device 10 is a processor or processing circuit that performs arithmetic processing related to knocking determination processing by performing arithmetic processing of a program stored in a ROM or a storage device with a CPU. The knocking determination device 10 may be a personal computer (PC) or the like having a program for executing the knocking detection method.

The knocking determination device 10 acquires an acquisition signal output from the data acquisition device 5 and angle information associated with the acquisition signal. The acquired signal corresponds to a physical quantity based on pressure fluctuation generated in each cylinder of the engine 1 per cycle. The acquired signal includes a spectrum (frequency component) in a partial section or a whole section in one cycle. The knocking noise is mainly included in the section including the ignition timing in one cycle, and the knocking noise appears as a feature amount in the spectrum.

First, with reference to FIG. 3, the relationship between the acquired signal, the target signal, and the determination signal in the knocking determination will be described.
The knocking determination device 10 acquires an acquisition signal including a sound pressure signal for one cycle of the engine 1 from the data acquisition device 5 at each sampling interval d, and holds the acquired signal. Further, the knocking determination device 10 determines the latest acquired signal as a determination signal for performing the knocking determination. In response to the determination of the determination signal, the knocking determination device 10 selects, as target signals, the necessary number m of acquisition signals acquired earlier than the determination signal and starting with signals that are closer in time to the determination signal. Therefore, a plurality of target signals are acquired as target signals from the “previous signal” immediately before the determination signal to the “oldest signal” of the past by the required number m. The time difference from the acquisition time of the determination signal to the acquisition time of the “oldest signal” is “sampling interval d × m necessary number”. Even if the engine 1 is in operation, if the time difference from the acquisition time of the determination signal to the acquisition time of the “oldest signal” is short, there is a low possibility that the operating conditions will change during the time difference. Therefore, by shortening the time difference from the acquisition time of the determination signal to the acquisition time of the "oldest signal" in an appropriate range, the increase of the possibility that the operating condition of the engine 1 changes can be suppressed. Therefore, knocking determination device 10 uses a plurality of target signals from “immediately before signal” to “oldest signal” as a reference for comparison, compares this with the determination signal, and determines whether the determination signal is a signal indicating knocking or not Determine

As shown in FIG. 2, the knocking determination device 10 includes a storage unit 20 that holds acquisition signals and the like, a management unit 60 that causes the storage unit 20 to hold signals necessary for knocking determination processing, and a knocking determination process from the storage unit 20. And a signal selection unit 30 for selecting a signal necessary for the In addition, knocking determination device 10 determines whether spectrum calculation unit 40 that calculates the spectrum of the acquired signal, bispectrum calculation unit 41 that calculates the bispectrum of the acquired signal, and whether the determination signal is a signal that indicates knocking. And a determination unit 50.

The storage unit 20 is configured by part or all of a storage device constituting the knocking determination device 10, and can store and delete acquisition signals, angle information, and the like. The storage unit 20 includes an acquisition signal area 201 which is a storage area related to an acquisition signal input by the knocking determination device 10 and a target signal area 202 which is a storage area related to a plurality of target signals used as comparison targets in knocking determination. It is provided. Further, the storage unit 20 is used as a determination signal area 203 which is a storage area related to a determination signal for which it is determined whether or not it is a signal indicating knocking, and a reference for determining whether it is a signal indicating knocking or not. A determination value area 204, which is a storage area related to the determination value, is provided.

The acquisition signal area 201 holds the acquisition signal input by the knocking determination device 10. The target signal area 202 holds information on a plurality of target signals selected from the acquired signals. For example, the number of target signals held in the target signal region 202 is the required number m or more required for the knocking determination process. The determination signal area 203 holds information on the determination signal selected from the acquired signal for performing the knocking determination. The determination value area 204 holds information on a determination value used to determine the presence or absence of knocking.

The management unit 60 associates the time information with the acquisition signal input by the knocking determination device 10, and stores the time information in the storage unit 20.
The management unit 60 determines and processes addition or non-existence of an acquisition signal as a determination signal to a target signal, and a data organizing unit that arranges acquisition signals and the like stored in the storage unit 20. And 63.

When the determination signal determined by the determination unit 50 as a signal indicating knocking is input as a result of the knocking determination process, the learning addition unit 62 does not add an acquisition signal corresponding to the determination signal to the target signal. That is, the determination signal is not included in the target signal. On the other hand, when the determination unit 50 determines that the signal is not a signal indicating knocking, an acquisition signal corresponding to the determination signal is added to the target signal. That is, the determination signal is included in the target signal.

In addition, the learning addition unit 62 sets the latest acquired signal as the target signal when the acquired signal is newly input even if the latest acquired signal is not selected as the determination signal, for example, before the knocking determination process is started. I will add it. Therefore, among the acquisition signals prior to the determination signal, an acquisition signal that is closer in time to the determination signal is prepared as the target signal.

In addition, the learning addition unit 62 causes the target signal region 202 to hold the target signal in the required number m or more required for the knocking determination process. The number of target signals to be held may not be set by the number, but may be set by the sampling interval d and the period.

The data organizing unit 63 organizes the acquired signal, the target signal, the determination signal, and the determination value stored in the storage unit 20 according to the defined conditions. For example, for the acquisition signal, the target signal, and the determination signal, the old acquisition signal, the target signal, or the determination signal exceeding the holding period is deleted. Also, for example, for the acquisition signal, the target signal, and the determination signal, the old acquisition signal, the target signal, or the determination signal exceeding the number of holdings is deleted. Furthermore, for example, when a new determination value is stored in the storage unit 20, the old determination value is deleted.

The signal selection unit 30 selects the target signal or the determination signal from the acquired signal based on the selection condition 31 for selecting the target signal and the determination signal. The selection condition 31 includes a condition for selecting a determination signal and a condition for selecting a target signal. The signal selection unit 30 selects the latest signal of the acquired signals as a determination signal whose presence or absence of knocking is determined based on the condition for selecting the determination signal (determination signal selection step). Further, based on the condition for selecting the target signal of the selection condition 31, the signal selection unit 30 corresponds to an acquisition signal closer to the determination signal in time among the acquisition signals prior to the determination signal from the target signal of the storage unit 20. The necessary number of signals are selected (target signal selection step). The necessary number is set, for example, in order to appropriately perform the knocking determination process. This required number is, for example, the number required to calculate the Mahalanobis distance.

Further, as the condition for selecting the target signal, a condition for acquiring the target signal from within a predetermined time range prior to the determination signal is also set. Normally, if the determination signal is closer in time, the operating condition of the engine 1 is less likely to change from the operating condition when the determination signal is obtained, and conversely, the operating condition of the engine 1 increases in time Is more likely to change from the operating condition when the determination signal is obtained. Therefore, a range in which the possibility of change from the operating condition is suppressed to a low level is set as a predetermined time range. By selecting the target signal from the acquisition signals prior to the determination signal, it is possible to determine whether the determination signal is a signal indicating a knocking signal under the current operating conditions.

In the present embodiment, the determination signal selection unit includes the signal selection unit 30, and the target signal selection unit includes the signal selection unit 30 and the learning addition unit 62 of the management unit 60.
The signal selection unit 30 determines an angle range in which knocking may occur from the target signal or the determination signal, and within the determined angle range (cut-out angle range) of the sound pressure signal included in the target signal or the determination signal. A signal cutting out unit 32 for cutting out a sound pressure signal is provided. The signal cut-out unit 32 specifies and cuts out the determined cut-out angle range based on the fact that the length of the target signal or the determination signal is one cycle. The cutting angle range is defined as a sound pressure signal within an angle range of about 90 degrees from the vicinity of an ignition position or TDC (Top Dead Center) specified from the start position of the target signal or the determination signal. In this embodiment, although the cutting angle range remains fixed even if the ignition timing is changed, the cutting angle range may be changed according to the change of the ignition timing.

The spectrum calculation unit 40 performs discrete Fourier transform on the target signal or the determination signal extracted by the signal extraction unit 32 in the time frequency domain to calculate a frequency component (spectrum). The discrete Fourier transform is performed, for example, by fast Fourier transform (FFT) that calculates discrete Fourier transform at high speed.

The bispectrum calculation unit 41 calculates a bispectrum as a value based on a spectrum from the frequency component calculated by the spectrum calculation unit 40. Here, it is assumed that the sound pressure signal cut out by the signal cutting out unit 32 at time t is x (t). When the sound pressure signal x (t) is subjected to FFT processing, a Fourier coefficient X (f) having the frequency f as a variable is calculated. The bispectrum B (f ₁ , f ₂ ) based on the Fourier coefficient X (f) is expressed by the following equation (1). The bispectrum B (f ₁ , f ₂ ) is the cube of the spectrum.

Here, f ₁ and f ₂ represent frequencies, and * represents complex conjugate.

In the present embodiment, the first calculation unit and the second calculation unit are configured by the spectrum calculation unit 40 and the bispectrum calculation unit 41. Further, each of the first calculation step and the second calculation step is composed of a spectrum calculation process and a bispectrum calculation process.

The determination unit 50 determines whether the determination signal is a signal indicating knocking.
Knocking is a kind of resonance phenomenon in a cylinder, and when knocking occurs, a shock wave is generated in the cylinder, and the vibration or sound generated from the engine due to the shock wave is a plurality of natural frequencies of the cylinder. The components of (resonance frequency) and their harmonic components (especially double frequency components) are included. The bispectrum of f ₁ = f _{2 in} the bispectrum reflects the magnitude of the second-order harmonic component at each frequency.

The natural frequency (resonance frequency) f _{p, q} of the cylinder of the engine is expressed by the following equation (2).

Where C is the velocity of sound, D is the bore diameter, p and q are vibration modes, and Ρ _{p and q} are constants in vibration mode (p, q). For example, when the vibration mode (p, q) is (1, 0) mode, P _1,0 = 1.841. In the knocking determination process, the entire frequency region of the acquired signal may be targeted. However, since knocking occurs according to the natural frequency of the engine cylinder of each vibration mode determined according to the engine 1, a sound resulting from knocking occurs in the natural frequency or its harmonics. Therefore, the presence or absence of knocking is appropriately determined by monitoring the natural frequency of each vibration mode and the periphery thereof and the harmonics thereof. That is, when performing the knocking determination process, the range of the spectrum or bispectrum is narrowed down to a predetermined frequency range including the natural frequency of the engine of each vibration mode determined according to the engine 1 to improve comparison accuracy or calculation load. Mitigation is planned. For example, for one acquired signal, a spectrum or five vibration modes of (1, 0), (2, 0), (0, 1), (3, 0), and (1, 1) are taken into consideration. By narrowing the frequency range of the bispectrum, it is possible to improve the comparison accuracy and reduce the calculation load.

The determination unit 50 includes a statistical parameter calculation unit 51 that calculates an average and a variance-covariance matrix of a plurality of target signals, and a normalization unit 52 that normalizes the target signal and the determination signal using the calculated statistical parameters. . In addition, the determination unit 50 calculates a determination value for knocking determination based on the normalized target signal, and a comparison unit that compares the determination value for knocking determination with the normalized determination signal. And 54.

First, the determination unit 50 normalizes the bispectrum B (f ₁ , f ₂ ) calculated by the bispectrum calculation unit 41.
The statistical parameter calculation unit 51 assumes that the bispectral variation of all target signals is a multidimensional probability distribution, and estimates the average and the variance covariance due to the bispectral variations of all target signals as statistical parameters ( calculate. At this time, the statistical parameter calculation unit 51 calculates statistical parameters from the frequency range in which the feature amount (frequency component of the bispectrum) of each vibration mode in the bispectrum occurs. For example, the statistical parameter calculation unit 51 calculates an absolute value from the feature amount of each vibration mode calculated for each of the plurality of target signals, and calculates an average value and a variance-covariance matrix for the plurality of target signals. By using this average value and the variance covariance matrix, it is possible to calculate the Mahalanobis distances for a plurality of target signals. The variance-covariance matrix is a matrix in which covariances, which are average values of products of deviations from the averages of the frequency components of the bispectrum, are arranged.

The normalization unit 52 calculates the Mahalanobis distance for the target signal and the bispectrum of the determination signal. Here, normalization is performed in multiple dimensions by calculating the Mahalanobis distance. Since the variance-covariance matrix used to calculate the Mahalanobis distance is a matrix in which covariances, which are the average value of products of deviations from the average of each frequency component of the bispectrum, are arranged, calculating the Mahalanobis distance is multidimensional. Normalization is performed at. More specifically, the dispersion of the intensity of each frequency of the spectrum of the target signal or judgment signal is compared with the dispersion (multidimensional) of the intensity of each frequency contained in the spectrum of the signal according to the dispersion-covariance matrix used to calculate the Mahalanobis distance And will be normalized.

At the time of determination value calculation processing, the normalization unit 52 calculates the Mahalanobis distance using the average value and the variance-covariance matrix of a plurality of target signals for all of the bispectrum of the plurality of target signals. Thereby, the Mahalanobis distance for all of the bispectrum of a plurality of target signals is calculated. That is, variation in the intensity of the spectrum of the target signal with respect to the statistical parameter is calculated. Then, based on these calculated Mahalanobis distances, a determination value used for knocking determination is calculated.

At the time of determination processing, the normalization unit 52 calculates the Mahalanobis distance for the bispectrum of the determination signal using an average value and a variance-covariance matrix for a plurality of target signals.
Thus, a value obtained by normalizing the frequency range included in the spectrum of the target signal or the determination signal can be obtained as a value obtained by normalizing with variations in multiple dimensions. In addition, since the frequency range included is normalized, there is a possibility that the knocking noise included in the determination signal may be extracted even if the vibration mode is not specified or slightly deviated. Therefore, normalization improves the possibility of determining whether the determination signal is a signal indicating knocking.

The determination value calculation unit 53 calculates a determination value that determines the degree of divergence between the normalized set obtained from the bispectrum of the target signal and the normalized value obtained from the bispectrum of the determination signal. . Here, the normalized set obtained from the bispectrum of a plurality of target signals is a set of Mahalanobis distances calculated for the bispectrum of each target signal. Also, the normalized value obtained from the bispectrum of the determination signal is the value of the Mahalanobis distance calculated for the bispectrum of the determination signal. That is, the determination value calculation unit 53 calculates a determination value that determines the degree of divergence between the set of Mahalanobis distances based on the plurality of target signals and the value of the Mahalanobis distance based on the determination signal.

The determination value calculation unit 53 calculates a determination value so as to have a margin for each of the Mahalanobis distances obtained for a plurality of target signals. For example, the determination value is determined as a value obtained by adding a predetermined value to an average value or a maximum value of a set of Mahalanobis distances, or a value obtained by multiplying a predetermined magnification, and a margin is calculated for the calculated Mahalanobis distance. Have. The determination value thus calculated is used to determine whether the determination signal is a signal indicating knocking.

The comparison unit 54 compares the Mahalanobis distance based on the determination signal with the determination value calculated by the determination value calculation unit 53 to determine whether the determination signal is a signal indicating knocking. If the value of the Mahalanobis distance based on the determination signal is larger than the determination value, the comparison unit 54 determines that the degree of deviation from the set of Mahalanobis distances based on each target signal is high, and the determination signal is a signal indicating knocking Determine Conversely, if the value of the Mahalanobis distance based on the determination signal is equal to or less than the determination value, the comparison unit 54 determines that the degree of deviation from the set of Mahalanobis distances based on each target signal is small, and the determination signal indicates knocking. Determine that it is not.

Next, the knocking determination process by the knocking determination device 10 will be described with reference to FIGS. 4 to 6. The knocking determination process exemplifies a case where the operating condition of the engine 1 is maintained constant. Operating conditions include conditions related to engine control such as changes in rotational speed of the engine 1 and engine mechanism (for example, valve opening / closing timing), ignition timing, EGR (Exhaust Gas Recirculation) amount changes, and external conditions such as load conditions. included. For example, it is desirable that the rotational speed of the engine 1 be the same when the determination signal is obtained and when a plurality of target signals are obtained. In addition, although there exists a possibility that determination accuracy may fall, this embodiment can be used also when driving | running conditions change gently. That is, even if the rotational speed at the time of obtaining the target signal is somewhat different, it may be a difference within the range where the determination signal including the knocking sound can be determined. In addition, with respect to sounds other than knocking detected from the engine 1, changes in operating conditions are permitted as long as the difference is in the range where the difference is suppressed to a small degree.

First, with reference to FIG. 4, data collection processing by the knocking determination device 10 will be described. The data acquisition process is performed in response to the acquisition signal being output from the data acquisition device 5.

As shown in FIG. 4, when the acquisition signal is output from the data collection device 5, the knocking determination device 10 inputs the acquired acquisition signal (step S 10), and the management unit 60 inputs the time to the acquisition signal. In association (step S11), the acquired signal area 201 of the storage unit 20 is stored so as to be in time order (step S12). The time to be associated here may be any one that can specify the relative order with respect to other acquired signals and the relative time difference. For example, the acquisition signal may be in a mode in which the time, a counter value, a code linked to the time, or the like may be associated or acquisition information may be arranged at a predetermined position of a list having an area for each sampling interval d. It is also good. When the previously stored acquisition signal is not selected as the determination signal, the management unit 60 adds the previously stored acquisition signal as the immediately preceding target signal.

Then, the data organizing unit 63 of the knocking determination device 10 organizes the data of the storage unit 20 (step S13), and ends the data collection process. Data organization deletes the oldest acquired signal in time when the capacity (number) of the acquired signal, the target signal, and the determination signal stored in the storage unit 20 exceeds a predetermined capacity (maximum number) respectively. Perform processing etc.

Subsequently, the determination value calculation process by the knocking determination device 10 will be described with reference to FIG. The determination value calculation process is performed in response to selection of the determination signal.
As shown in FIG. 5, when the determination value calculation process is started, the knocking determination device 10 acquires the latest acquisition signal by selecting it as a determination signal by the signal selection unit 30 (step S20). The time is acquired (step S21). The time of the determination signal is obtained from the time associated with the determination signal. Subsequently, the knocking determination device 10 selects a plurality of target signals that match the selection condition based on the relationship with the time of the determination signal in the signal selection unit 30 (step S22). That is, a plurality of target signals suitable for the selection condition based on the relationship with the determination signal based on the relationship with the time of the determination signal are selected. When a plurality of target signals are selected, knocking determination device 10 calculates the spectrum of each target signal in spectrum calculation unit 40 (step S23). The calculated spectrum is held in the storage unit 20, for example, the target signal area 202. Further, the knocking determination device 10 calculates the bispectrum from the spectrum of each target signal in the bispectrum calculation unit 41 (step S24). The bispectrum calculation unit 41 calculates the bispectrum of the target signal from the spectrum of each target signal held in the storage unit 20, and holds the calculated bispectrum of each target signal in the target signal region 202 of the storage unit 20. . In the knocking determination device 10, the statistical parameter calculation unit 51 extracts mode-specific feature quantities from the bispectrum of each target signal (step S25). That is, the frequency range corresponding to the vibration mode of the cylinder of the engine 1 is extracted from the bispectrum of each target signal. Next, the knocking determination device 10 calculates statistical parameters by the statistical parameter calculation unit 51 (step S26). The statistical parameter includes an average (μ) calculated from bispectrum of a plurality of target signals and a variance-covariance matrix (Σ), and the mean and the variance-covariance matrix are calculated for each vibration mode. The calculated statistical parameters are stored in the determination value area 204 of the storage unit 20. In the knocking determination device 10, the normalization unit 52 normalizes each target signal based on the statistical parameters calculated in step S26 (step S27). More specifically, the Mahalanobis distance of each target signal is normalized by calculation for each vibration mode. In the knocking determination device 10, the determination value calculation unit 53 determines the determination value for each mode (step S28), and ends the determination value calculation process.

If each target signal for which the statistical parameter is calculated does not contain a signal indicating knocking or if it is small, the Mahalanobis distance calculated based on this statistical parameter is an index indicating the similarity to a signal not indicating knocking. Therefore, the Mahalanobis distance of the signal not indicating knocking is obtained as a small value, and the Mahalanobis distance of the signal indicating knocking is obtained as a large value. In addition, if the Mahalanobis distance corresponds to the frequency range corresponding to the vibration mode, the probability that the increase of the value is caused by the loud sound caused by knocking becomes high. Therefore, it is possible to determine whether or not the determination signal is a signal indicating knocking by using the determination value for each vibration mode defined here.

Subsequently, determination processing (determination step) of knocking determination by knocking determination apparatus 10 will be described with reference to FIG. This determination process is performed subsequent to the determination value calculation process.
As shown in FIG. 6, when the determination process is started, knocking determination device 10 obtains the determination signal selected by signal selection unit 30 (step S30), and obtains the time of the determination signal (step S31). ). When the determination signal is acquired, the knocking determination device 10 calculates the spectrum of the determination signal by the spectrum calculation unit 40 (step S32). The calculated spectrum is held in the determination signal area 203 of the storage unit 20. Further, the knocking determination device 10 calculates the bispectrum from the spectrum of the determination signal in the bispectrum calculation unit 41 (step S33). The bispectrum of the calculated determination signal is held in the determination signal area 203 of the storage unit 20. The knocking determination device 10 extracts the mode-specific feature amount from the bispectrum of the determination signal in the normalization unit 52 (step S34). That is, the frequency range corresponding to the vibration mode is extracted from the bispectrum of the determination signal. Then, the knocking determination device 10 normalizes the determination signal in the normalization unit 52 using the statistical parameter calculated in the determination value calculation process (step S26) (step S35). More specifically, the mean (μ) and the variance covariance matrix (Σ) are selected from the storage unit 20 for each vibration mode, and the Mahalanobis of the determination signal is selected based on the selected mean (μ) and the variance covariance matrix (Σ). It is normalized by calculating the distance. The knocking determination device 10 obtains the determination value for each vibration mode from the storage unit 20 by the comparison unit 54 (step S36), and compares the Mahalanobis distance of the determination signal with the determination value for each mode by the comparison unit 54 (step S37). ). That is, the Mahalanobis distance of each vibration mode of the determination signal is compared with the determination value of the corresponding vibration mode. Then, if the Mahalanobis distance of the determination signal is less than the determination value of the compared vibration mode, it is determined that knocking has not occurred in the vibration mode, and conversely, if it is larger than the determination value of the compared vibration mode It is determined that knocking has occurred in the vibration mode. Then, knocking determination device 10 outputs the determination result (step S38), and ends the determination value calculation process. The determination result to be output is, for example, whether or not knocking has occurred, and a vibration mode in which knocking has occurred or has not occurred. Thereby, the convenience concerning adjustment of the engine 1 is improved.

Next, with reference to FIGS. 7 and 8, updating of the target signal in the knocking determination device 10 will be described.
First, with reference to FIG. 7, the outline of the update of the target signal by the knocking determination device 10 will be described.

When the latest acquisition signal is sequentially input, the knocking determination device 10 selects the input acquisition signal as the next determination signal. When the latest acquisition signal is input, the management unit 60 adds the determination signal so far to the target signal as the previous signal. On the other hand, when the number of target signals increases and exceeds the required number m, the management unit 60 counts the number of required signals more than m, for example, when one is added, the oldest target of the increased number of target signals. Remove the signal from the signal of interest. In this way, the required number m of target signals from the immediately preceding signal to the oldest signal are selected. In addition, the time difference from the acquisition time of the latest signal to the acquisition time of the oldest signal is also maintained at “sampling period d × m necessary number”.

That is, in response to a new determination signal being selected, the management unit 60 adds the previously acquired acquisition signal to the target signal, and updates the target signal by removing the oldest signal of the target signal. Note that the update of the target signal may be performed in response to the new acquisition signal being input to the knocking determination device 10, even if a new determination signal is not selected.

With reference to FIG. 8, when the selected determination signal is a signal indicating knocking, a learning process in which this determination signal is not added to the target signal will be described. This learning process is performed following the end of the knocking determination of the determination signal.

When the learning process is started, the management unit 60 of the knocking determination device 10 acquires the determination result of the determination signal (step S40), and determines whether the determination result is no knocking (step S41). If it is not determined that knocking has not occurred (NO in step S41), the learning addition unit 62 does not add the determination signal to the target signal (step S44). Then, the learning process is ended.

On the other hand, if it is determined that knocking is not present (YES in step S41), the learning addition unit 62 of the knocking determination device 10 adds the determination signal to the target signal (step S42). Then, the data organizing unit 63 of the knocking determination device 10 organizes data (step S43), and ends the learning process.

Thereby, when the acquisition signal corresponding to the determination signal determined to be a signal indicating knocking or not is a signal indicating knocking, the acquisition signal is not included in the target signal, so the signal indicating knocking is included. The possibility of not being Then, the accuracy of the knocking determination can be further enhanced by comparing the determination signal with the target signal.

As described above, according to the present embodiment, the following effects can be obtained.
(1) The target signal to be compared with the determination signal whose presence or absence of knocking is determined is selected based on the condition determined by the relationship with the determination signal (for example, the relationship in time or the operating condition). That is, by selecting based on the relationship with the determination signal, the target signal can be selected as one suitable for comparison with the determination signal. Thereby, knocking determination can be suitably performed under various conditions.

Then, using statistical parameters (average and variance-covariance matrix) determined from values based on the spectrum of each target signal (such as sound and vibration), values based on the spectrum of each target signal are normalized with variations in multiple dimensions of the same value. To obtain normalized values, and the above statistical parameters are used to normalize values based on the spectrum of the determination signal with variations in multiple dimensions to obtain normalized values. Then, the degree of divergence between the set of normalized values of the plurality of target signals and the normalized value of the determination signal is determined. That is, it is determined that the determination signal is a signal indicating knocking because the degree of deviation is large. In addition, there is a Mahalanobis distance as an example of a value obtained by normalizing with variations in multiple dimensions.

(2) The bispectrum in which the feature quantity at the frequency appears largely is used to determine whether the determination signal is a signal indicating knocking or not. Thereby, the presence or absence of knocking can be determined. Knocking is a kind of resonance phenomenon in a cylinder. When knocking occurs, a shock wave is generated in the cylinder, and the vibration or sound emitted from the engine is a component of multiple natural frequencies (resonance frequencies) of the cylinder. And their harmonic components (especially double frequency components). Since the bispectrum is a feature that reflects the co-occurrence relation of frequency components, the possibility of extraction of knocking included in the spectrum is increased.

Further, the determination accuracy of knocking can be improved by making the determination based on the natural frequency of the cylinder of the engine 1 where knocking appears in the determination of whether the determination signal is a signal indicating knocking or not.

(3) The target signal is selected from the acquired signal acquired at a point close to the time when the determination signal is obtained. That is, an acquisition signal that is temporally distant from the acquisition time of the determination signal is not selected as the target signal. As a result, an acquisition signal having a high possibility that the operating condition of the internal combustion engine does not change or the change is small because it is close in time to the acquisition time of the determination signal is selected as the target signal, and the knocking determination accuracy is improved. It is possible.

Further, a predetermined number of target signals are selected from a plurality of acquired signals obtained within a predetermined period from the acquisition time of the determination signal. That is, by setting the time interval between the acquisition time of the determination signal and the acquisition time of the target signal within a predetermined period, the operating condition of the internal combustion engine when the determination signal and the target signal are respectively acquired does not change. Or, the change is likely to be small. It is possible to more appropriately determine whether the determination signal is a signal indicating knocking or not by comparing with the target signal.

(4) Since an acquisition signal to be a target signal is already acquired at the time when the determination signal is acquired, it is immediately determined whether the determination signal is a signal indicating knocking, for example, knocking determination processing in real time It can be done. That is, the time from the selection of the determination signal to the determination as to whether or not the determination signal is a signal indicating knocking can be shortened.

(5) Since the acquisition signal corresponding to the determination signal determined to indicate knocking is not included in the target signal in subsequent selection, the relative difference between the determination signal indicating knocking and the target signal is increased, and the target signal It is determined with higher accuracy whether the determination signal is a signal indicating knocking or not by the comparison of.

(6) Since the normalized values based on a plurality of target signals, which are compared with the normalized values based on the determination signal, are corrected to be large values, that is, to include the margin, it takes a determination of knocking Adjustment of sensitivity and improvement of accuracy can be achieved.

Second Embodiment
Hereinafter, a second embodiment of the knocking determination device and the knocking determination method will be described with reference to FIGS. 9 to 15. The knocking determination apparatus and the knocking determination method according to this embodiment are different from the first embodiment in that the knocking determination process is performed based on a target signal acquired in advance for each operating condition. Hereinafter, differences from the first embodiment will be mainly described. In addition, for convenience of explanation, the same reference numerals are given to the same configuration, and the description is omitted.

The knocking determination device 10 of the present embodiment shown in FIG. 9 performs the knocking determination process of the determination signal after preparing the prior signal in the data collection process for acquiring the prior signal.
First, with reference to FIG. 10, the relationship between the advance signal and the determination signal in knocking determination will be described. The knocking determination device 10 holds a predetermined number of advance signals for each rotational speed. For example, the rotational speed is divided into 1000 to 5000 [r / min] every 100 [r / min], and the predetermined number of advance signals for each rotational speed is R 1000 to R 5000, respectively. Then, when the rotation speed of the determination signal is 3000 [r / min], a signal of 3000 [r / min] which is the same rotation speed as the prior signal is selected as the target signal. At this time, when the number of target signals of the same rotation speed is insufficient to the required number m, signals included in a range where the rotation speed is similar (close) (for example, 2900 [r / min] or 3100 [r / min] Signal) is also selected as the target signal.

The knocking determination device 10 shown in FIG. 9 obtains an acquisition signal, angle information, and various current operating conditions of the engine 1 from the data collection device 5. The data acquisition device 5 associates the acquired information with the angle information and the current various operating conditions of the engine 1 output by the engine ECU 2 and outputs the information to the knocking determination device 10. The data acquisition device 5 associates angle information and operating conditions with the sound pressure signal of part or all of the acquired signal. The various operating conditions include conditions that affect the sound generated from the engine 1, for example, rotational speed, engine mechanism change (e.g., valve opening and closing timing), EGR amount change, operation mode, load condition, and the like.

The management unit 60 of the knocking determination device 10 includes a pre-addition unit 61, a learning processing unit 64, and a data organizing unit 65, and the storage unit 20 includes an a priori signal area 211 and a target signal area 212 for holding a prior signal. And are provided. The knocking determination device 10 uses the prior signal held in the prior signal region 211 for the knocking determination process on the determination signal.

The pre-addition unit 61 is a data collection process performed in advance of the knocking determination process, in which acquisition signals acquired in advance from the engine 1 under each of the operating conditions operated under a plurality of operating conditions under the condition that knocking does not occur , And stored in the prior signal area 211.

When it is determined that the determination signal is not a signal indicating knocking, the learning processing unit 64 adds the determination signal to the prior signal region 211 of the acquisition signal acquired in advance under the operating condition of the determination signal.

The data organizing unit 65 performs data organizing such as deleting each of the advance signal, the target signal, the determination signal, and the determination value based on a predetermined condition.
The prior signal area 211 holds the previously acquired prior signal as one or more prior signals classified for each driving condition.

The target signal area 212 holds the target signal selected from the prior signals that are the same as or similar to the operating conditions of the determination signal each time the determination signal is selected.
Subsequently, the data collection process by the knocking determination device 10 will be described with reference to FIG. The knocking determination device 10 acquires sound pressure signals and angle information of the engine 1 operated under a plurality of operating conditions in which the rotational speed is changed under normal operating conditions in which knocking does not occur during operation in preparation for determination. This acquisition takes place until prior signals of the type and number of operating conditions for which acquisition is required are obtained. In the present embodiment, the case where the operating condition to be changed is the rotational speed is exemplified, but the type of the operating condition to be changed may be other than the rotational speed.

When the data collection process is started, the knocking determination device 10 sets an operating condition (rotational speed) of an acquisition signal to be acquired (step S50). The operating condition (rotational speed) set by the knocking determination device 10 is shared by the engine ECU 2 so that the advance signal necessary for the knocking determination process can be appropriately acquired. The knocking determination device 10 acquires the acquisition signal by the advance addition unit 61 (step S51), and acquires the operating condition (rotational speed) associated with the acquisition signal (step S52). The knocking determination device 10 classifies the acquired signal according to the operating condition (rotational speed) by the preliminary adding unit 61 (step S53), and causes the preliminary signal area 211 to hold the signal as the preliminary signal for each operating condition (rotational speed) (step S54). In the knocking determination device 10, the advance addition unit 61 determines whether or not the acquisition signal is acquired under the same operating condition (step S55). Here, when the prior signal of the set operating condition (rotational speed) does not reach the predetermined number prepared in advance, it is determined that acquisition is further necessary, and when the predetermined number is reached, it is determined that further acquisition is not necessary. Be done. Here, when it is determined that acquisition is necessary under the same operating condition (rotational speed) (YES in step S55), the knocking determination device 10 returns the process to step S51 and executes the subsequent steps.

On the other hand, when it is determined that no further acquisition is necessary under the same operating condition (rotational speed) (NO in step S55), knocking determination device 10 determines whether to change the operating condition (rotational speed) (step S56). Here, when there is an operating condition (rotational speed) for which the prior signal has not been acquired, it is determined that the operating condition (rotational speed) is changed, and there is no operating condition (rotational speed) for which the prior signal is not acquired. It is determined that the condition (rotational speed) is not changed. Here, when it is determined that the operating condition (rotational speed) is to be changed (YES in step S56), knocking determination device 10 returns the process to step S50, and no advance signal is acquired for the operating condition (rotational speed) Set the operating condition (rotational speed) and execute the subsequent steps. On the other hand, when it is determined that the operating condition (rotational speed) is not changed (NO in step S56), a predetermined number of advance signals are held for each operating condition (rotational speed), and knocking determination device 10 performs data organization The operation (step S57) ends the data collection process.

Thereby, the knocking determination device 10 acquires an acquisition signal when the engine 1 is operated under the normal operation condition, for each rotational speed. For example, a predetermined number, for example, R 1000, of acquired signals when the rotational speed is 1000 [r / min] is acquired and held in the prior signal area 211 as an a priori signal with the rotational speed as the operation condition. Similarly, a predetermined number of acquisition signals, for example, R1100 to R5000, are acquired every 100 [r / min] up to a rotational speed of 1100 to 5000 [r / min], and the advance signal is used as a prior signal with the rotational speed as the operating condition. The signal area 211 is held.

When the prior signal is held, knocking determination device 10 acquires an acquisition signal when engine 1 is operated under the test operation condition, selects the acquired acquisition signal as a determination signal, and performs knocking determination on the selected determination signal. Do the processing.

First, determination value calculation processing by knocking determination device 10 will be described with reference to FIG. 12. The determination value calculation process is performed each time selection of a determination signal is performed.
As shown in FIG. 12, when the knocking determination device 10 starts the determination value calculation process, the signal selection unit 30 acquires the latest acquisition signal as a determination signal (step S60), and the operating condition of the determination signal (rotation The speed is acquired (step S61). The operating condition (rotational speed) of the determination signal is obtained from the operating condition associated with the determination signal. Subsequently, the knocking determination device 10 selects a plurality of target signals conforming to the selection condition 33 based on the relationship with the operation condition of the determination signal in the signal selection unit 30 (step S62). That is, a plurality of target signals that match the selection condition 33 which is the operating condition of the determination signal are selected.

For example, assuming that the rotational speed as the operating condition of the determination signal is 3000 [r / min], the signal selecting unit 30 similarly has the rotational speed as the operating condition of 3000 [r / min] according to the selection condition 33. The necessary number m of pre-signals are acquired, and these are set as a plurality of target signals. When the required number m of advance signals can not be acquired under the same operation condition as the determination signal, the advance signal under the same operation condition as the operation condition of the determination signal is also acquired. For example, in the case where the number of prior signals having a rotational speed of 3000 [r / min] does not meet the required number of m, the similar range is different by 100 [r / min] in the range (2900 to 3100 [r / min] In the meantime, the preliminary signal is supplemented, and if it is not enough, a necessary number m of preliminary signals are acquired in a similar wider range of operating conditions.

The subsequent processing procedure is the same as that of the first embodiment. That is, when a plurality of target signals are selected, knocking determination device 10 calculates the spectrum of each target signal by spectrum calculation unit 40 (step S23) and causes storage unit 20 to hold the spectrum, and bispectral calculation unit 41 makes each target The bispectrum is calculated from the spectrum of the signal (step S24) and stored in the storage unit 20. In the knocking determination device 10, the statistical parameter calculation unit 51 extracts the feature quantity classified by mode from the bispectrum of each target signal (step S25), and the statistical parameter calculation unit 51 calculates statistical parameters (step S26). Hold. The normalization unit 52 normalizes each target signal (calculates the Mahalanobis distance) based on the calculated statistical parameters (step S27), and the determination value calculation unit 53 determines mode-specific determination values (step S28), The determination value calculation process ends.

Subsequently, determination processing by the knocking determination device 10 will be described with reference to FIG. This determination process is performed subsequent to the determination value calculation process.
As shown in FIG. 13, when the determination processing is started, knocking determination device 10 obtains the determination signal selected by signal selection unit 30 (step S70), and obtains the operating condition (rotational speed) of the determination signal. (Step S71). Since the determination process is performed subsequent to the determination value calculation process, the processes of steps S70 and S71 are replaced with the processes performed in step S60 and step S61 of the determination value calculation process. In addition, when there is no need to re-execute the determination value calculation process such as no change in the operating conditions, the determination process may be performed without performing the determination value calculation process. In that case, since the process of step S60 and step S61 of the determination value calculation process is not performed, the process of step S70 and step S71 is performed in the determination process to acquire a determination signal. In addition, it is preferable to use the operating condition of the determination signal acquired in the determination process for determining whether the determination based on the target signal is appropriate.

The subsequent processing procedure is the same as that of the first embodiment. That is, when the determination signal is selected, knocking determination apparatus 10 calculates the spectrum of the determination signal by spectrum calculation unit 40 (step S 32) and causes storage unit 20 to hold the spectrum, and bispectrum calculation unit 41 calculates the spectrum of the determination signal The bispectrum is calculated (step S33) and stored in the storage unit 20. The normalization unit 52 extracts feature quantities classified by mode from the bispectrum of the determination signal (step S34), and the normalization unit 52 normalizes the determination signal using the statistical parameters calculated in the determination value calculation process (step S26). (Calculation of the Mahalanobis distance) is performed (step S35). The comparison unit 54 acquires the determination value for each vibration mode from the storage unit 20 (step S36), and the comparison unit 54 compares the Mahalanobis distance of the determination signal with the determination value for each mode (step S37). Then, the determination result is output (step S38), and the determination value calculation process is ended.

Next, with reference to FIG. 14 and FIG. 15, the learning processing of the advance signal in the knocking determination device 10 will be described.
First, with reference to FIG. 14, an outline of the updating of the advance signal by the knocking determination device 10 will be described. The knocking determination device 10 adds a determination signal determined to be not a signal indicating knocking in the knocking determination process to the prior signal held in the prior signal area 211. For example, the learning processing unit 64 determines the determination signal of the operation condition (rotational speed) 3000 [r / min] determined not to be the signal indicating knocking by the determination unit 50 as the prior signal of the rotational speed 3000 [r / min]. Add as. Further, for example, the learning processing unit 64 adds a determination signal of the operating condition (rotational speed) 3050 [r / min] determined not to be a signal indicating knocking by the determination unit 50 as a priori signal. At this time, since the prior signal of the operating condition (rotational speed) 3050 [r / min] is not held in the prior signal area 211, the rotational speed 3050 [r / min] is selected as the new operating condition (rotational speed). Is added, and the rotational speed 3050 [r / min] of this added operating condition (rotational speed) is added as a prior signal.

The procedure of the learning process for adding the determination signal to the prior signal area 211 will be described with reference to FIG. This learning process is performed when the knocking determination process of the determination signal ends.
When the learning process is started, the knocking determination device 10 causes the learning processing unit 64 to obtain the determination result of the determination signal (step S40), and determines whether the determination result is no knocking (step S41). If it is not determined that knocking has not occurred (NO in step S41), the learning processing unit 64 does not add the determination signal to the prior signal (step S441). Then, the learning process is ended.

On the other hand, if it is determined that knocking is not present (YES in step S41), the knocking determination device 10 adds the determination signal to the advance signal in the learning processing unit 64 (step S421). Then, the knocking determination device 10 causes the data organizing unit 63 to organize data (step S431), and ends the learning process.

In this manner, the learning process is expected to increase the accuracy of the target signal selected from the prior signals by increasing the number of prior signals for the operating conditions, and the determination signal to be compared with the selected target signal. The determination accuracy of the knocking determination can be improved.

In addition, by adding a new type of operating condition (rotational speed) by learning processing, the possibility that the determination signal is compared with the prior signal that is more similar to the operating condition is increased, so the determination accuracy of knocking determination is improved. Is taken.

As described above, according to the present embodiment, in addition to the effects described in (2) and (6) of the first embodiment, the effects described below can be exhibited.
(7) The target signal to be compared with the determination signal whose presence or absence of knocking is determined is selected based on the condition determined by the relationship with the determination signal (the relationship in the operating condition). That is, by selecting the target signal based on the relationship with the determination signal, the target signal can be selected as one suitable for comparison with the determination signal. Thereby, knocking determination can be suitably performed under various conditions.

(8) Since the prior signal to be the target signal has already been acquired when the determination signal is acquired, it is immediately determined whether the determination signal is a signal indicating knocking, for example, knocking determination processing in real time It can be done. That is, the time from the selection of the determination signal to the determination as to whether or not the determination signal is a signal indicating knocking can be shortened.

(9) Since the acquisition signal is acquired in advance under a plurality of operating conditions as not including knocking, it is possible to acquire a target signal of the operating condition suitable for determining whether the determination signal is a signal indicating knocking or not. it can.

Also, signals having operating conditions highly relevant to the operating conditions of the determination signal are acquired as target signals, and these are compared with the determination signal. As a result, for the determination signal acquired while the operating condition changes sequentially, the target signal having the operating condition close to the operating condition at the time of acquisition is selected, and the knocking determination is suitably performed.

(10) The relevance of the operating conditions can be determined by the rotational speed of the engine 1. Since the rotational speed of the engine 1 also affects the magnitude and frequency of the sound generated in the engine 1, the determination accuracy of knocking can be improved by comparing the acquired signal with a target signal having a similar rotational speed of the engine 1.

(11) Since the determination signal in which knocking has not occurred is added to the prior signal, the prior signal can be enhanced to improve the determination accuracy of knocking. Also, the advance signal may be added with an advance signal of a new operating condition.

Third Embodiment
The third embodiment of the knocking determination device and the knocking determination method will be described below with reference to FIGS. 16 to 18. The knocking determination apparatus and the knocking determination method according to this embodiment are different from the first and second embodiments in that the knocking determination process is performed by normalizing the spectrum without calculating the bispectrum. Hereinafter, for convenience of explanation, differences from the first embodiment will be mainly described, and the same reference numerals are given to the same configurations, and the description will be omitted.

The knocking determination device 10 will be described with reference to FIG.
The knocking determination device 10 includes the storage unit 20, the management unit 60, the signal selection unit 30, the spectrum calculation unit 40, and the determination unit 50, as in the first embodiment, while the bispectral calculation is performed. The unit 41 is not provided. In the present embodiment, the first calculation unit and the second calculation unit are configured by the spectrum calculation unit 40.

Therefore, the determination unit 50 normalizes the spectrum calculated by the spectrum calculation unit 40 as a value based on the spectrum.
That is, assuming that the dispersion of spectra of all target signals is a multidimensional probability distribution, the statistical parameter calculation unit 51 estimates (calculates an average and a variance covariance due to the dispersion of spectra of all target signals as statistical parameters (calculation ). At this time, the statistical parameter calculation unit 51 calculates statistical parameters from a frequency range in which a feature amount (frequency component of spectrum) in each vibration mode in the spectrum is generated.

In addition, the normalization unit 52 calculates the Mahalanobis distance for the spectrum of the target signal or the determination signal. The variance-covariance matrix used to calculate the Mahalanobis distance is a matrix in which covariances, which are the mean value of products of deviations from the average of each frequency component of the spectrum, are arrayed, so calculating the Mahalanobis distance is multidimensional. Normalization is performed at.

At the time of determination value calculation processing, the normalization unit 52 calculates the Mahalanobis distance for all of the spectra of the plurality of target signals. Then, based on these calculated Mahalanobis distances, a determination value used for knocking determination is calculated.

At the time of determination processing, the normalization unit 52 calculates the Mahalanobis distance with respect to the determination signal with respect to the spectrum of the determination signal.
Furthermore, the determination value calculation unit 53 calculates a determination value that determines the degree of divergence between the normalized set obtained from the spectrum of the target signal and the normalized value obtained from the spectrum of the determination signal. . Here, the normalized set obtained from the spectra of a plurality of target signals is a set of Mahalanobis distances calculated for the spectra of each target signal. Also, the normalized value obtained from the spectrum of the determination signal is the value of the Mahalanobis distance calculated for the spectrum of the determination signal. That is, the determination value calculation unit 53 calculates a determination value that determines the degree of divergence between the set of Mahalanobis distances based on the plurality of target signals and the value of the Mahalanobis distance based on the determination signal. The determination value calculation unit 53 calculates a determination value so as to have a margin for the Mahalanobis distance obtained based on a plurality of target signals.

Further, the comparison unit 54 determines whether the determination signal is a signal indicating knocking or not based on comparing the Mahalanobis distance based on the spectrum of the determination signal with the determination value calculated by the determination value calculation unit 53. .

As described above, whether or not the determination signal is a signal indicating knocking is also determined by the value obtained by normalizing the spectrum of the target signal and the value obtained by normalizing the spectrum of the determination signal.
Next, with reference to FIG. 17, the determination value calculation process by the knocking determination device 10 will be described. The determination value calculation process of the present embodiment is different from the determination value calculation process of the first embodiment only in that the procedure of the bispectrum calculation (step S24) is removed.

That is, as shown in FIG. 17, when the determination value calculation process is started, the knocking determination device 10 selects and acquires the latest acquisition signal as a determination signal in the signal selection unit 30 (step S20) Time is acquired (step S21). Subsequently, the signal selection unit 30 selects a plurality of target signals that match the selection condition based on the relationship with the time of the determination signal (step S22), and calculates the spectrum of each selected target signal (step S23).

Then, the knocking determination device 10 uses the statistical parameter calculation unit 51 to extract the mode-specific feature quantities from the spectrum of each target signal (step S25), and calculate the frequency range corresponding to the vibration mode of the engine 1 from the spectrum of each target signal. Statistical parameters are calculated (step S26). The normalization unit 52 normalizes each target signal based on the statistical parameters calculated in step S26 (step S27), and the determination value calculation unit 53 compares the Mahalanobis distance of each target signal for each vibration mode by mode. The determination value is determined (step S28), and the determination value calculation process ends.

Subsequently, the determination process by the knocking determination apparatus 10 will be described with reference to FIG. This determination process is performed subsequent to the determination value calculation process. The determination process of the present embodiment is different from the determination process of the first embodiment only in that the procedure of the bispectrum calculation (step S33) is removed.

That is, as shown in FIG. 18, when the determination process is started, knocking determination device 10 obtains the determination signal selected by signal selection unit 30 (step S30), and obtains the time of the determination signal (step S30) Step S31). Then, the spectrum calculation unit 40 calculates the spectrum of the determination signal (step S32). The normalization unit 52 extracts mode characteristic quantities from the spectrum of the determination signal (step S34), and normalizes the spectrum of the determination signal using statistical parameters corresponding to the frequency range corresponding to the vibration mode of the engine 1 Perform (step S35). The comparison unit 54 acquires the determination value for each vibration mode from the storage unit 20 (step S36), and compares the Mahalanobis distance of the determination signal with the determination value for each mode (step S37). Then, the determination result is output (step S38), and the determination value calculation process is ended.

In this way, it is also determined whether the determination signal is a signal indicating knocking or not based on the normalized value of the spectrum of the target signal and the normalized value of the spectrum of the determination signal.
As described above, according to the present embodiment, in addition to the effects described in (1) and (3) to (6) of the first and second embodiments, the following effects can be achieved.

(12) By not performing the bispectral calculation process, an increase in the processing load can be suppressed, and it becomes easy to ensure real-time property.
Fourth Embodiment
The fourth embodiment of the knocking determination device and the knocking determination method will be described below with reference to FIGS. 19 to 21. The knocking determination apparatus and the knocking determination method according to this embodiment are different from the first to third embodiments in that statistical parameters are updated without being sequentially calculated from a target signal. Hereinafter, for convenience of explanation, differences from the first embodiment will be mainly described, and the same reference numerals are given to the same configurations, and the description will be omitted.

The knocking determination device 10 will be described with reference to FIG.
As shown in FIG. 19, the knocking determination device 10 includes a storage unit 20, a signal selection unit 30, a spectrum calculation unit 40, a bispectrum calculation unit 41, and a determination unit 50.

The storage unit 20 is provided with an acquisition signal area 201, a determination signal area 203, a determination value area 204, and a statistical parameter area 213 which is a storage area related to statistical parameters used for knocking determination.

The statistical parameter area 213 holds the statistical parameter calculated by the determination unit 50 and also holds the initial value of the statistical parameter. As the initial value of the statistical parameter, a value set in advance, a value calculated in the mode described in the first to third embodiments, and the like can be mentioned.

The signal selection unit 30 includes a signal extraction unit 32. The signal selection unit 30 selects, based on the condition for selecting the determination signal, the latest signal among the acquired signals as a determination signal for which the presence or absence of knocking is determined.

The determination unit 50 includes a statistical parameter calculation unit 51A as a target signal selection unit and an update unit, a normalization unit 52 as a calculation unit, a determination value acquisition unit 53A, and a comparison unit 54 as a determination unit.

The statistical parameter calculation unit 51A, as described in the first embodiment, assumes that the variation of the bispectrum of all the target signals is a multidimensional probability distribution, and averages the variation of the bispectrum of all the target signals. And the variance / covariance as statistical parameters. In the present embodiment, the statistical parameter calculation unit 51A does not actually calculate using all target signals, but calculates statistical parameters by a method equivalent to calculation using all target signals.

The statistical parameter calculation unit 51A will be described with reference to FIG. Here, it is assumed that the immediately preceding signal is present in the past closest to the determination signal, and a plurality of target signals are present in the past relative to the immediately preceding signal. First, it is assumed that the previous statistical parameters (average, variance covariance) are calculated based on each spectrum acquired from a plurality of target signals. When a new immediately preceding signal under predetermined conditions is added to the plurality of target signals, the spectrum of the immediately preceding signal is calculated, and the calculated spectrum of the immediately preceding signal is input to the statistical parameter calculation unit 51A. The predetermined condition is that the signal corresponds to the position immediately before the determination signal in terms of the determination signal.

The statistical parameter calculation unit 51A updates the statistical parameter with the spectrum of the immediately preceding signal input. That is, the statistical parameter calculation unit 51A updates the statistical parameter to obtain a new statistical parameter by reflecting the value obtained from the spectrum of the previous signal on the corresponding parameter of the statistical parameter (average, variance covariance) Do the processing. For example, the statistical parameter calculation unit 51A gives a weight of “α” to the value obtained from the spectrum of the immediately preceding signal, gives a weight of “1-α” to the value of the old statistical parameter (average), Perform update processing. Thus, the new statistical parameter is such that the contribution of the immediately preceding signal is greater than the contribution of the statistical parameter. As the statistical parameter updating process is repeated, the degree of contribution to the statistical parameter becomes smaller as the previous signal is the largest and the past signal.

The normalization unit 52 calculates the Mahalanobis distance for the bispectrum of the determination signal. That is, at the time of determination processing, the normalization unit 52 calculates the Mahalanobis distance for the bispectrum of the determination signal based on the statistical parameter.

The determination value acquisition unit 53A acquires a determination value to be compared with the calculated Mahalanobis distance from the determination value area 204 of the storage unit 20.
The comparison unit 54 determines whether or not the determination signal is a signal indicating knocking, on the basis of comparing the Mahalanobis distance based on the determination signal with the determination value acquired by the determination value acquisition unit 53A.

The statistical parameter update process will be described with reference to FIG. This update process is performed following the end of the knocking determination of the determination signal.
When the update process is started, the parameter calculation unit 51A of the knocking determination device 10 acquires the determination result of the determination signal (step S40), and determines whether the determination result is no knocking (step S41). If it is determined that knocking is present (NO in step S41), the parameter calculation unit 51A does not update statistical parameters (step S46). On the other hand, if it is determined that knocking is not present (YES in step S41), the parameter calculation unit 51A updates the statistical parameter (step S45). Then, the statistical parameter update process is ended.

As described above, according to the present embodiment, in addition to the effects described in (1) to (6) of the first embodiment, the following effects can be achieved.
(13) By updating the statistical parameter itself, it is possible to reduce the number of past acquired signals and target signals required for calculating the statistical parameter. That is, it is possible to reduce the time and effort required to manage and select the target signal. For example, proper maintenance of a predetermined number of signals may be unnecessary. In addition, since the statistical parameters calculated in the past are used, the processing load can be reduced, for example, by reducing the process of calculating statistical parameters from the target signal.

(14) By adjusting the weight at the time of updating the statistical parameter, it is possible to adjust the responsiveness, stability, accuracy and the like related to knocking determination.
(Other embodiments)
In addition, said each embodiment can also be implemented with the following forms which changed this suitably.

In the above-described embodiments, in step S37 of the determination process, it is determined whether knocking has occurred by comparison with the Mahalanobis distance calculated as the determination value. However, even if it is determined whether or not knocking has occurred by comparing the Mahalanobis distance calculated based on the determination signal with a value determined merely to determine an abnormal value without performing the comparison in step S37. Good.

-In each said embodiment, although illustrated about the case where a Mahalanobis distance is calculated | required on the assumption that it is multidimensional probability distribution, multidimensional probability distribution assumed the occurrence probability that assumed other multidimensional probability distributions, such as mixing Gaussian distribution, It may be determined whether knocking is occurring or not. In the case of other multidimensional probability distributions, the value obtained by taking the logarithm of the probability density function is taken as the anomalous degree.

In the first to third embodiments, calculation of the variance-covariance matrix in the statistical parameters may be performed by a minimum-covariance-determination (MCD) method.

In the first embodiment, the case where the acquisition signal corresponding to the determination signal determined not to be the signal indicating knocking is added to the target signal is illustrated. However, the present invention is not limited to this, and regardless of the knocking determination result, an acquired signal corresponding to the determination signal may be added to the target signal. If a signal indicating knocking is added to the target signal, the accuracy of the knocking determination may decrease, but if the other target signal is not a signal indicating knocking, the target signal indicates knocking from the determination signal. In some cases the signal can be determined.

In the second embodiment, the case where the acquired signal corresponding to the determination signal determined not to be the signal indicating knocking is added to the prior signal is illustrated. However, the present invention is not limited to this, and the determination signal or the acquisition signal may be added to the advance signal regardless of the knocking determination result. Also in this case, the knocking determination process may be performed based on the advance signal, as described above.

In the second embodiment, the knocking determination device 10 changes the rotational speed of the engine 1 by 100 [r / min], and holds a predetermined number of advance signals for each rotational speed. However, the present invention is not limited to this, and the knocking determination device may sweep-change the rotational speed of the engine to acquire and hold the advance signal. In this case, the signal selection unit selects a predetermined number of signals whose rotational speed is close to the determination signal as the target signal. Further, the rotational speed of the engine may be changed in one direction of the low speed direction or the high speed direction, or may be changed to repeat the low speed direction and the high speed direction. Even with such advance signals, it is possible to select the required number of advance signals corresponding to the rotational speed close to the determination signal as target signals.

In the second embodiment, the case where the acquired signal corresponding to the determination signal determined not to be the signal indicating knocking is added to the prior signal is illustrated. However, the present invention is not limited to this, and regardless of the knocking determination result, the acquisition signal corresponding to the determination signal may not be added to the advance signal. Even in this case, the knocking determination process can be performed based on the existing advance signal.

In each of the above embodiments, the case where the determination signal or the spectrum or bispectrum of the target signal is calculated each time the determination value calculation process or the determination process is illustrated. However, the present invention is not limited to this, and the spectrum or bispectrum of the determination signal or the target signal may be calculated in advance and held in the storage unit. As a result, it is possible to adjust the timing of calculating the spectrum or the bispectrum to share the load of the arithmetic processing.

For example, as shown in FIG. 22, the storage unit 20 may be provided with an acquisition signal spectrum area 205 for holding the spectrum of the acquisition signal.
At this time, as shown in FIG. 23, in the determination value calculation process, the spectrum acquisition of the target signal (step S221) is performed instead of the target signal selection (step S22) and the spectrum calculation (step S23) of the first embodiment. To be executed. More specifically, the signal selection unit 30 selects a target signal that matches the selection condition based on the relationship with the time of the determination signal, and the spectrum corresponding to the selected target signal is acquired from the acquired signal spectrum region 205 of the storage unit 20. It may be selected.

-In the said, 1st and 3rd embodiment, it illustrated about the case where the acquisition signal before a determination signal is selected in order close in time to a determination signal, and it is set as several object signal. However, the present invention is not limited to this, and the target signal may be selected to skip, for example, so as not to include a part of the acquired signal in the target signal.

As shown in FIG. 24, a part of the acquisition signal may not be adopted as the rejection signal to the target signal, and the past acquisition signals may be adopted as the target signal by the number of rejection signals. In this case, the time difference between the acquisition time of the determination signal and the acquisition time of the oldest signal is “sampling interval d × (n target signals + n rejection signals k)”, but this time difference can be selected as the target signal If it is within the time range, a plurality of target signals can be selected with a part of the acquired signal as a rejection signal. Note that the rejection signal is an acquisition signal that can be relatively easily determined to be abnormal, such as a signal that includes noise that is likely to adversely affect knocking determination. This suppresses the selection of an inappropriate acquisition signal as the target signal, and the knocking determination accuracy is maintained.

-In the said, 1st and 3rd embodiment, it illustrated about the case where the newest signal is selected as a determination signal among acquisition signals. However, the present invention is not limited to this, and the determination signal may be arbitrarily selected from acquired acquisition signals. Even in this case, the knocking determination process can be performed on the determination signal by selecting the target signal before the determination signal. In addition, it is possible to perform knocking determination processing on past data and the like of the acquired signal.

-In the said, 1st and 3rd embodiment, it illustrated about the case where the acquisition signal of time earlier than a determination signal is made into a several object signal. However, the present invention is not limited to this, a plurality of target signals may be selected from acquisition signals temporally after the determination signal, or even if a plurality of target signals are selected from acquisition signals temporally before and after the determination signal. Good. In particular, when knocking determination processing is to be performed later based on log data of the acquired signal, etc., it is possible to select a target signal to be used for knocking determination processing from before the determination signal in time. It can be selected later in time, or can be selected in time before or after the determination signal.

For example, as shown in FIG. 25A, the necessary number m of target signals may be selected from the acquired signals after the determination signal is selected. At this time, the time difference from the acquisition time of the determination signal to the acquisition time of the latest signal is “sampling interval d × m required number”. However, if this time difference is within the time range selectable as the target signal, A plurality of target signals can be selected from acquired signals of Then, the target signal is prepared as an acquisition signal closer in time to the determination signal among the acquisition signals after the determination signal.

According to such a configuration, a signal obtained after the determination signal can be used for determination. For example, if the acquisition signal acquired before the determination signal is not suitable for comparison with the determination signal, the acquisition signal acquired after the determination signal can be used. This makes it possible to more suitably determine whether the determination signal is a signal indicating knocking.

Further, for example, as shown in FIG. 25B, a required number m of target signals may be selected from acquired signals before and after the determination signal. At this time, the time difference between the acquisition times of the target signal and the acquisition time of the determination signal can be reduced by selecting the target signals in order from the smallest absolute value of the time difference from the acquisition time of the determination signal to the acquisition time of the latest signal. For example, the maximum value of the time difference from the acquisition time of the determination signal to the acquisition time of the latest signal is “sampling interval d × preselection number m1” or “sampling interval d × post selection number m2” (however, the required number m = pre-selection number m1 + post-selection number m2). If there is an acquisition signal before and after the determination signal, the maximum value of the time difference here is the time difference when acquiring the target signal from the acquisition time earlier than the acquisition time of the determination signal, and acquisition of the determination signal The operation condition is similar when the target signal is obtained, which is shorter than any of the time differences when acquiring the target signal from the acquisition time after the time, and the operation signal when the determination signal is obtained is similar. The possibilities are even greater. Then, the target signal is prepared as an acquisition signal that is closer in time to the determination signal among the acquisition signals before and after the determination signal. In addition, since the possibility that the maximum value of the time difference is within the time range selectable as the target signal is also increased, the possibility of appropriately performing the knocking determination process is also increased.

According to such a configuration, since the time difference between the acquisition time of the target signal and the acquisition time of the determination signal can be further shortened, the operating condition and the determination signal when the target signal is obtained are obtained. The possibility that the operating conditions at the time are the same is further enhanced, and the accuracy in determining whether the determination signal is a signal indicating knocking can be improved.

In each of the above embodiments, the case where the knocking determination process is performed in consideration of the frequency range in which the feature amount (frequency component of the spectrum) of each vibration mode in the bispectrum or spectrum occurs is exemplified. However, the present invention is not limited to this, and the knocking determination process may be performed in consideration of the entire frequency band of a bispectrum or spectrum or a predetermined frequency range arbitrarily determined.

-In each said embodiment, it illustrated about the case where a sound pressure signal is acquired by the sound pressure sensor 4 as a sound which is a vibration of air, based on the physical quantity based on the pressure fluctuation which generate | occur | produces in the engine 1. FIG. However, the present invention is not limited to this, and the physical quantity based on pressure fluctuation generated in the internal combustion engine is not limited to the sound which is a signal of air, and may be a physical quantity correlating to knocking. It may be acceleration (vibration) of the internal combustion engine.

For example, as shown in FIG. 26, the engine 1 may be provided with an in-cylinder pressure sensor 7, and a signal related to the pressure from the in-cylinder pressure sensor 7 may be input to the data acquisition device 5 to generate an acquisition signal. Further, an acceleration sensor 8 may be provided in the engine 1 and a signal related to the acceleration from the acceleration sensor 8 may be input to the data acquisition device 5 to generate an acquisition signal. That is, various physical quantities obtained from the engine 1 can be used for the knocking determination process.

-In each above-mentioned embodiment, a case where an acquisition signal close in time to the determination signal is a target signal, and a case in which a preliminary signal whose operation condition is close to the determination signal is a target signal have been described. . However, the present invention is not limited to this, and may have both a configuration in which an acquisition signal that is temporally close to the determination signal is a target signal, and a configuration in which a preliminary signal whose driving condition is close to the determination signal is a target signal. Then, depending on the operating conditions of the engine 1, a determination method may be selected in which the determination of the knocking determination process can be performed with high accuracy.

For example, as shown in FIG. 27, the knocking determination device 10 includes the learning addition unit 62 and the first data organizing unit 63 in the management unit 60, and the pre-addition unit 61, the learning processing unit 64, and the second data organizing unit And 65. In addition, the storage unit 20 includes an acquisition signal area 201, a first target signal area 202, a determination signal area 203, and a determination value area 204, and also includes an a priori signal area 211 and a second target signal area 212. Furthermore, the signal selection unit 30 includes the selection condition 31, the signal extraction unit 32, and the determination method selection unit 35. Thereby, the knocking determination device 10 causes the advance addition unit 61 to hold the advance signal in the advance signal area 211, causes the learning processing unit 64 to learn, and causes the second data organizing unit 65 to organize. In the knocking determination apparatus 10, the management unit 60 causes the acquisition signal area 201 to hold the acquisition signal for the target signal selected according to the temporal condition, and causes the learning addition unit 62 to add the determination signal to the target signal. The first data organizing unit 63 organizes the signals and the like. The first target signal area 202 holds the first target signal, and the second target signal area 212 holds the second target signal. The first data organizing unit 63 organizes data on the first target signal, and the second data organizing unit 65 organizes data on the second target signal.

Then, based on the operation condition, the determination method selection unit 35 of the signal selection unit 30 performs the knocking determination process with the first target signal selected from the acquired signal based on the temporal condition based on the method selection condition. It is determined whether to perform with the second target signal selected from the prior signals. More specifically, the selection based on the temporal condition is the first selection, and the condition determined in relation to the determination signal is close to the time when the determination signal is obtained and within a predetermined period from the determination signal. This is a condition for selecting a plurality of target signals from the condition for selecting a predetermined number of signals from a certain acquired signal. Further, the selection based on the operating condition is the second selection, and the condition determined by the relationship with the determination signal is set as the operating condition highly relevant to at least one condition of the operating condition corresponding to the determination signal, This is a condition for selecting a plurality of target signals from the prior signals.

As an example of the method selection condition, when the operating condition changes or greatly changes, the determination based on the target signal by the second selection is performed, and the determination based on the target signal by the first selection is performed otherwise It is a condition. According to this, the second selection is performed while the operating condition of the engine 1 is changing, and the acquired signal in the changing operating condition is the target signal, and the knocking determination accuracy that may occur when the first selection is adopted Can be prevented. In addition, another example of the method selection condition is that the determination based on the target signal by the first selection is performed when there is no prior signal or there is a shortage, and the determination based on the target signal by the second selection otherwise. Is a condition to According to this, it is possible to prevent the lowering of the knocking determination accuracy caused by the lack of the advance signal.

The operating condition of the engine 1 causes a change in the pressure fluctuation generated in the engine 1, and the tendency of the value indicating the physical quantity contained in the acquired signal indicating the physical quantity based on this also changes significantly. Therefore, if the operating conditions of the engine 1 are largely different between the target signal and the determination signal, it is appropriately determined whether the determination signal is a signal indicating knocking even if the comparison is based on the target signal and the determination signal. It is difficult to do. On the other hand, according to this configuration, according to the operating conditions of the engine 1, the signal to be compared with the determination signal is the first selection (temporal condition) for the determination signal, and the second selection It is switched to one of (corresponding operating conditions). Thereby, it is determined whether the determination signal is a signal indicating knocking or not based on the target signal selected in consideration of the operating condition of the engine 1.

Alternatively, the second selection may be selected when the operating condition of the engine 1 largely changes within a predetermined period from the time when the acquisition signal is acquired. That is, when it is not appropriate to use the target signal according to the first selection due to fluctuation of the operating condition of the engine 1 to determine whether the acquired signal is a signal indicating knocking, the target signal according to the second selection Can be used to properly determine knocking.

-In said other embodiment, the structure which makes an object signal an acquisition signal close | temporally to a determination signal as object signal, and the structure which makes an object signal a prior signal whose operation condition is close to a determination signal is object, The case where the determination method which can perform determination of a knocking determination process with high precision was selected according to conditions was illustrated. However, the present invention is not limited to this, and an acquisition signal that is temporally close to the determination signal and a prior signal whose operation condition is close to the determination signal may be selected and used as the target signal. For example, in the above other embodiments, the first selection and the second selection are both selected, and the number of selection of acquisition signals temporally close to the determination signal is set as the first allocation number, The selection number of the prior signals whose operating conditions are close to the signal may be set as the second allocation number, and these may be combined and selected as the target signal. At this time, the sum of the first allocation number and the second allocation number may be set to be the required number which is the number of data necessary for the knocking determination process. The ratio between the first allocation number and the second allocation number may be half or half, or an appropriate ratio may be set based on experience, experiments, theory, or the like.

For example, this will be described using FIG. 27 for the sake of convenience. The signal selection unit 30 selects the condition determined by the relationship with the determination signal from the acquired signal that is close to the time when the determination signal is obtained and within a predetermined period from the determination signal, for the first allocation number. And, a second assignment number is selected from the advance signals associated with the highly relevant operating conditions to at least one of the operating conditions corresponding to the determination signal. Then, the signal selection unit 30 selects a combination of the selected acquisition signal of the first allocation number and the advance signal of the second allocation number as a plurality of target signals. Based on the plurality of target signals thus selected, it is determined whether or not knocking of the determination signal has occurred.

The operating conditions of the engine 1 controlled under many conditions may be difficult to predict its change. On the other hand, according to this configuration, both the acquired signal in which the determination signal is selected based on the temporal condition with respect to the determination signal, and the advance signal selected in accordance with the corresponding operating condition are combined. It is compared with the signal of interest. This makes it possible to more suitably determine whether the determination signal is a signal indicating knocking or not by comparison with a target signal that is a highly flexible signal with respect to fluctuations in the operating conditions of the engine 1.

If it is explained that it is a signal with high flexibility, from the acquired signal selected based on the temporal condition, the target signal becomes the noise that is generated by the operation of the engine 1 at that time, the fluctuation of the operation at that time It is selected in the form that includes Then, knocking determination is performed based on the target signal on which such fluctuation is reflected. In addition, when processing in real time, in order to make a determination immediately after acquisition of a determination signal, the signal used for determination may be constrained to a past signal, or securing of the number of appropriate data that can be used for determination can not be guaranteed. is there. On the other hand, the acquisition signal selected based on the operating condition is not only a signal close to the operating condition but also a signal in the direction in which the operating condition changes from now on, so the operating condition changes from the current condition. Knocking determination can be performed in consideration of the manner in which the vehicle is moving. Note that the fluctuation of the sound occurring in the engine 1 and the fluctuation of the sound of the prior signal may be largely different. That is, by mixing the acquisition signal selected based on the temporal condition and the acquisition signal selected based on the operating condition, the advantage in the determination based on each signal is taken advantage of, and the determination based on each signal It also compensates for weaknesses.

Claims

A knocking determination device that determines the presence or absence of knocking based on an acquired signal indicating a physical quantity based on a pressure fluctuation generated in an internal combustion engine, comprising:
A determination signal selection unit configured to select a determination signal for determining the presence or absence of knocking from the acquired signal;
A target signal selection unit that selects a plurality of target signals from the acquired signal based on conditions determined in relation to the determination signal;
A first calculator configured to calculate values based on the spectra of the plurality of target signals;
A second calculator configured to calculate a value based on the spectrum of the determination signal;
And a determination unit that determines whether the determination signal is a signal indicating knocking,
The determination unit is
Estimating statistical parameters from values based on the spectra of the plurality of target signals;
Normalizing the value based on the spectrum of each of the target signals using the statistical parameter with the variation in the same value in multiple dimensions to obtain a normalized value,
Normalizing the value based on the spectrum of the determination signal with variations in multiple dimensions using the statistical parameter to obtain a normalized value,
It is determined that the determination signal is a signal indicating knocking based on the fact that the degree of divergence between a set of normalized values for the plurality of target signals and the normalized value for the determination signal is large. As configured, the knocking determination device.
The value based on the spectrum of each target signal is a bispectral value calculated based on the spectrum of each target signal, and the value based on the spectrum of the determination signal is calculated based on the spectrum of the determination signal The knocking determination device according to claim 1, which is a value of the bispectrum.
The determination unit uses, as a value based on the spectrum of each of the target signals, a value of a frequency range that takes into account the natural frequency of a cylinder in the internal combustion engine, and as a value based on the spectrum of the determination signal in the internal combustion engine The knocking determination device according to claim 1, wherein the knocking determination device is configured to use a value of a frequency range that takes into account a natural frequency of a cylinder.
The target signal selection unit is configured to obtain a predetermined number of acquisition signals among a plurality of acquisition signals obtained within a predetermined period from a time when the determination signal is obtained, near the time when the determination signal is obtained. The knocking determination device according to any one of claims 1 to 3, configured to be selected as the plurality of target signals.
The knocking determination device according to claim 4, wherein the target signal is a signal obtained before a time when the determination signal is obtained.
The knocking determination device according to claim 4, wherein the target signal is a signal obtained before and after a time when the determination signal is obtained.
The knocking determination device according to claim 4, wherein the target signal is a signal obtained after a time when the determination signal is obtained.
The target signal selection unit is configured not to include an acquisition signal corresponding to the determination signal in the target signal when the determination unit determines that the determination signal is a signal indicating knocking. The knocking determination device according to any one of 1 to 7.
The acquisition signal includes a plurality of advance signals previously acquired from the internal combustion engine when the internal combustion engine is operated under a plurality of operating conditions including a condition in which knocking does not occur.
The target signal selection unit selects a plurality of target signals from the prior signals obtained under operating conditions highly relevant to at least one of the plurality of operating conditions corresponding to the determination signal. The knocking determination device according to any one of claims 1 to 3, which is configured to select.
The knocking determination device according to claim 9, wherein the operating condition is a rotational speed of an internal combustion engine.
The knocking determination apparatus according to claim 9, further comprising a learning processing unit that adds the determination signal that is determined not to be a signal indicating knocking by the determination unit to the prior signal.
The acquisition signal includes a plurality of advance signals previously acquired from the internal combustion engine when the internal combustion engine is operated under a plurality of operating conditions including a condition in which knocking does not occur.
The target signal selection unit acquires a first allocation number from a plurality of acquisition signals obtained within a predetermined period from a time when the determination signal is obtained, near the time when the determination signal is obtained. Among the plurality of operating conditions, a second allocation number of the second allocated number from the prior signal obtained under the operating condition highly relevant to at least one operating condition corresponding to the determination signal, as well as selecting the signal. The system according to any one of claims 1 to 3, wherein a prior signal is selected, and the acquisition signal of the selected first assignment number and the prior signal of the second assignment number are used as the plurality of target signals. The knocking determination device according to any one of the preceding claims.
The acquisition signal includes a plurality of advance signals previously acquired from the internal combustion engine when the internal combustion engine is operated under a plurality of operating conditions including a condition in which knocking does not occur.
The target signal selection unit selects the plurality of target signals from a plurality of acquisition signals obtained within a predetermined period from a time when the determination signal is obtained, near the time when the determination signal is obtained. Among the plurality of operating conditions, a plurality of target signals are obtained from the prior signals obtained under operating conditions highly relevant to at least one of the plurality of operating conditions corresponding to the determination signal. Configured to perform alternatively the second selection process of selecting
The target signal selection unit is configured to select and execute any one of the first selection process and the second selection process according to the operating condition of the internal combustion engine. The knocking determination device according to any one of the preceding claims.
The target signal selection unit selects and executes the second selection process in response to a large change in the operating condition of the internal combustion engine within a predetermined period from the time when the determination signal is acquired. The knocking determination device according to claim 13, configured to select and execute the first selection process when the second selection process is not selected.
The determination unit corrects the value after normalization for each of the target signals to be large, and compares the corrected set of normalized values with the value after normalization for the determination signal. The knocking determination device according to any one of claims 1 to 14, which is configured as follows.
A knocking determination device that determines the presence or absence of knocking based on an acquired signal indicating a physical quantity based on a pressure fluctuation generated in an internal combustion engine, comprising:
A determination signal selection unit configured to select a determination signal for determining the presence or absence of knocking from the acquired signal;
A target signal selection unit that selects a target signal from the acquired signal based on a condition determined based on a relationship with the determination signal;
A calculation unit that calculates a value based on the spectrum of the determination signal;
A determination unit that determines whether the determination signal is a signal indicating knocking;
The updating unit updating the statistical parameter based on the value based on the spectrum of the target signal;
The determination unit normalizes the value based on the spectrum of the determination signal using the statistical parameter with variation in multiple dimensions to obtain a normalized value, and a predetermined determination value and the normalized value A knocking determination device configured to determine that the determination signal is a signal indicating knocking based on the fact that the degree of deviation is large.
The target signal selection unit is configured to include in the target signal a determination signal that is determined by the determination unit not to be a signal indicating knocking.
17. The apparatus according to claim 16, wherein the updating unit is configured to update the statistical parameter in a manner of weighting each of the statistical parameter and a value based on a spectrum of the target signal immediately before the determination signal. Knocking judgment device.
A knocking determination method performed by a knocking determination device that determines the presence or absence of knocking based on an acquired signal indicating a physical quantity based on a pressure fluctuation generated in an internal combustion engine,
Selecting the determination signal for determining the presence or absence of knocking from the acquired signal;
The knocking determination device selects a plurality of target signals from the acquired signal based on conditions determined in relation to the determination signal;
The knocking determination device calculates values based on the spectra of the plurality of target signals, respectively;
The knocking determination device calculates a value based on a spectrum of the determination signal;
The knocking determination device determines whether the determination signal is a signal indicating knocking;
The above determination is
Estimating statistical parameters from values based on the spectra of the plurality of target signals;
Normalizing the values based on the spectrum of each of the target signals with variations in the same multidimensional values using the statistical parameters to obtain normalized values;
Normalizing the value based on the spectrum of the determination signal with variations in multiple dimensions using the statistical parameter to obtain a normalized value;
It is determined that the determination signal is a signal indicating knocking based on the fact that the degree of divergence between a set of normalized values for the plurality of target signals and the normalized value for the determination signal is large. Knocking judgment method including