JP4186655B2 - Knock sensor abnormality detection device and abnormality detection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for detecting an abnormality of a knock sensor provided in an internal combustion engine, and more particularly to a technique for improving the accuracy of detecting an abnormality.
[0002]
[Prior art]
The engine is provided with a knock sensor for detecting knocking in order to grasp the combustion state and perform optimum ignition control. A signal output from the knock sensor is input to a control device such as an ECU (Electronic Control Unit), and predetermined ignition control is executed. Therefore, in order to execute this ignition control accurately, it is necessary to detect whether or not the knock sensor is abnormal.
[0003]
For this purpose, for example, Japanese Patent Laid-Open No. 6-101563 (Patent Document 1) discloses a knock sensor abnormality detection device in which abnormality detection accuracy is improved by variably setting an abnormality determination level. This device includes a knock sensor attached to an internal combustion engine, a first detection circuit for detecting on / off of an electric load of the internal combustion engine, and on / off of the electric load and the rotational speed of the internal combustion engine as parameters. A calculation circuit that calculates an abnormality determination level based on the created map; and a determination circuit that determines whether the knock sensor is abnormal by comparing a signal obtained by integrating the output signal from the knock sensor with the abnormality determination level. .
[0004]
According to the abnormality detection device disclosed in Patent Document 1, when the rotational speed of the internal combustion engine and the on / off of the electric load are detected, an abnormality determination level is calculated based on a map value created in advance. This abnormality determination level is calculated so as not to include the influence of noise generated in the electric load system. For this reason, than the abnormality determination level calculated by only the rotational speed of the internal combustion engine can reduce the possibility of error detection. Thereby, the detection accuracy of the knock sensor abnormality can be improved.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 6-101563 [0006]
[Problems to be solved by the invention]
However, according to the abnormality detection device disclosed in the above publication, the signal from the knock sensor includes the signal in each cylinder of the internal combustion engine, while the abnormality determination level of the knock sensor is commonly used for each cylinder. Therefore, there has been a case where the knock sensor abnormality cannot be accurately detected.
[0007]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a knock sensor abnormality detection device and an abnormality detection method capable of accurately detecting an abnormality of the knock sensor. .
[0008]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a knock sensor abnormality detection device comprising: a receiving means for receiving a signal from a knock sensor; and a signal received from a sensor provided in an internal combustion engine. Recognizing means for recognizing cylinders, acquisition means for acquiring a recognized cylinder determination value from among predetermined determination values for each cylinder, signals received from the knock sensor, and acquired Determination means for determining whether or not the knock sensor is abnormal based on the determination value.
[0009]
According to the first invention, when the recognizing unit recognizes one of the cylinders based on the signal received from the sensor provided in the internal combustion engine, the acquiring unit determines the predetermined value for each cylinder. The determination value of the cylinder recognized from the values is acquired. When the receiving unit receives a signal from the knock sensor, the determining unit determines whether or not the knock sensor is abnormal based on the signal and the determination value. In this way, since the state of the knock sensor can be determined based on the information for each cylinder, it is possible to accurately detect the abnormality of the knock sensor. Thereby, it is possible to provide a knock sensor abnormality detecting device capable of accurately detecting abnormality of the knock sensor.
[0010]
In the knock sensor abnormality detection device according to the second aspect of the invention, in addition to the configuration of the first aspect, the acquisition means pre-determines for each cylinder when the recognized cylinder is a predetermined cylinder. Means for acquiring a determination value of a specific cylinder from the determined determination values is included.
[0011]
According to the second invention, by setting a cylinder serving as a reference for detecting an abnormality of the knock sensor, it is determined whether or not there is an abnormality based on information relating to the cylinder, and a determination based on information relating to other cylinders. Is not done. As a result, it is possible to prevent erroneous detection of the knock sensor.
[0012]
In the knock sensor abnormality detection device according to the third aspect of the invention, in addition to the configuration of the second aspect of the invention, the specific cylinder is a cylinder determined based on a position where the knock sensor is attached to the internal combustion engine.
[0013]
According to the third aspect of the invention, the abnormality of the knock sensor is detected by a signal related to a specific cylinder (for example, a cylinder closest to the knock sensor, a cylinder located on both sides of the knock sensor, etc.) determined based on the position where the knock sensor is attached. It can be detected accurately.
[0014]
In addition to the configuration of any one of the first to third aspects, the knock sensor abnormality detection device according to the fourth aspect of the invention corresponds to a predetermined determination value for each cylinder corresponding to the rotational speed of the internal combustion engine. It is a fixed value. The abnormality detection device further includes a rotation speed detection means for detecting the rotation speed of the internal combustion engine. The acquisition means includes means for acquiring a recognized cylinder determination value from among predetermined determination values for each cylinder based on the detected rotational speed of the internal combustion engine.
[0015]
According to the fourth invention, when the rotational speed acquisition means acquires the rotational speed of the internal combustion engine, the cylinder determination value recognized from the predetermined determination values corresponding to the rotational speed of the internal combustion engine is acquired. . If it does in this way, abnormality of a knock sensor can be detected corresponding to the operating state (rotational speed) of an internal-combustion engine.
[0016]
In addition to the configuration of any one of the first to fourth inventions, the abnormality detection device for a knock sensor according to a fifth aspect of the invention is configured such that when the signal received from the knock sensor exceeds a determination value obtained, Means for determining that the sensor is normal.
[0017]
According to the fifth invention, when the signal from the knock sensor exceeds the acquired determination value, the knock sensor is determined to be normal.
[0018]
According to a sixth aspect of the knock sensor abnormality detection device, in addition to the configuration of any one of the first to fourth aspects of the invention, the determination means knocks when the signal received from the knock sensor falls below the acquired determination value. An abnormality determining means for determining that the sensor is abnormal is included.
[0019]
According to the sixth aspect, when the signal from the knock sensor falls below the acquired determination value, the knock sensor is determined to be abnormal.
[0020]
In addition to the configuration of the sixth invention, the abnormality detection device for a knock sensor according to a seventh aspect of the invention calculates the number of times that the abnormality detection device has been determined to be less than the acquired determination value for the signal received from the knock sensor. It further includes a calculation means for The abnormality determining means includes means for determining that the knock sensor is abnormal when the number of times calculated by the calculating means exceeds a predetermined number.
[0021]
According to the seventh aspect, the knock sensor is not determined to be abnormal until the predetermined number of times that the signal received from the knock sensor is determined to be below the determination value. The predetermined number of times is a number of times set in advance based on the characteristic value of each sensor. In this way, it is possible to prevent erroneous detection of the knock sensor by an abnormal signal or the like.
[0022]
According to an eighth aspect of the present invention, there is provided a knock sensor abnormality detection method comprising: receiving a signal from a knock sensor; and receiving one signal from each cylinder based on a signal received from a sensor provided in an internal combustion engine. Based on the recognition step for recognizing, the acquisition step for acquiring the determination value of the recognized cylinder from the predetermined determination values for each cylinder, the signal received from the knock sensor and the acquired determination value, A determination step of determining whether or not the knock sensor is abnormal.
[0023]
According to the eighth invention, when one cylinder is recognized from each cylinder based on a signal received from a sensor provided in the internal combustion engine in the recognition step, each cylinder is recognized in the acquisition step. A cylinder determination value recognized from predetermined determination values is acquired. When a signal from the knock sensor is received in the reception step, it is determined in the determination step whether or not the knock sensor is abnormal based on the signal and the determination value. In this way, since the state of the knock sensor can be determined based on the information for each cylinder, it is possible to accurately detect the abnormality of the knock sensor. Thereby, the abnormality detection method of the knock sensor which can detect the abnormality of a knock sensor exactly can be provided.
[0024]
In the knock sensor abnormality detection method according to the ninth aspect of the invention, in addition to the structure of the eighth aspect of the invention, the acquisition step may be performed in advance for each cylinder when the recognized cylinder is a predetermined specific cylinder. A step of obtaining a determination value of a specific cylinder from the determined determination values is included.
[0025]
According to the ninth aspect, by setting a cylinder serving as a reference for detecting an abnormality of the knock sensor, it is determined whether or not there is an abnormality based on information relating to the cylinder, and a determination based on information relating to other cylinders. Is not done. As a result, it is possible to prevent erroneous detection of the knock sensor.
[0026]
In the knock sensor abnormality detection method according to the tenth aspect of the invention, in addition to the configuration of the ninth aspect, the specific cylinder is a cylinder determined based on a position where the knock sensor is attached to the internal combustion engine.
[0027]
According to the tenth invention, the knock sensor abnormality is detected by a signal related to a specific cylinder (for example, a cylinder closest to the knock sensor, a cylinder located on both sides of the knock sensor, etc.) determined based on a position where the knock sensor is attached. It can be detected accurately.
[0028]
In the knock sensor abnormality detection method according to the eleventh aspect of the invention, in addition to the configuration of any of the eighth to tenth aspects of the invention, the predetermined determination value for each cylinder corresponds to the rotational speed of the internal combustion engine. It is a fixed value. The abnormality detection method further includes a rotation speed detection step of detecting the rotation speed of the internal combustion engine. The acquisition step includes a step of acquiring a recognized cylinder determination value from among predetermined determination values for each cylinder based on the detected rotational speed of the internal combustion engine.
[0029]
According to the eleventh invention, when the rotational speed of the internal combustion engine is acquired in the rotational speed acquisition step, the cylinder determination value recognized from the predetermined determination values corresponding to the rotational speed of the internal combustion engine. Is acquired. If it does in this way, abnormality of a knock sensor can be detected corresponding to the operating state (rotational speed) of an internal-combustion engine.
[0030]
In the knock sensor abnormality detection method according to the twelfth invention, in addition to the configuration of any of the eighth to eleventh inventions, if the determination step exceeds the determination value obtained by the signal received from the knock sensor, Determining that the sensor is normal.
[0031]
According to the twelfth aspect, when the signal from the knock sensor exceeds the acquired determination value, it is determined that the knock sensor is normal.
[0032]
In the knock sensor abnormality detection method according to the thirteenth aspect of the present invention, in addition to the configuration of any of the eighth to eleventh aspects of the invention, the determination step knocks when the signal received from the knock sensor falls below the acquired determination value. An abnormality determination step for determining that the sensor is abnormal is included.
[0033]
According to the thirteenth aspect, when the signal from the knock sensor falls below the acquired determination value, the knock sensor is determined to be abnormal.
[0034]
In addition to the configuration of the thirteenth invention, the knock sensor abnormality detection method according to the fourteenth invention further includes a calculating step of calculating the number of times that the signal received from the knock sensor is determined to be below the acquired determination value. Including. The abnormality determination step includes a step of determining that the knock sensor is abnormal when the number of times calculated in the calculation step exceeds a predetermined number.
[0035]
According to the fourteenth aspect, the knock sensor is not determined to be abnormal until the predetermined number of times that the signal received from the knock sensor is determined to be lower than the determination value. The predetermined number of times is a number of times set in advance based on the characteristic value of each sensor. In this way, it is possible to prevent erroneous detection of the knock sensor by an abnormal signal or the like.
[0036]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.
[0037]
<First Embodiment>
A first embodiment of the present invention will be described with reference to FIGS.
[0038]
FIG. 1 is a block diagram of a knock sensor abnormality detection device according to the present embodiment. This knock sensor abnormality detection process is executed by engine ECU 100.
[0039]
The abnormality detection device includes an engine ECU 100, a knock sensor 140, a cam angle sensor 150, a crank angle sensor 160, and an igniter 170 connected to the engine 130.
[0040]
Engine ECU 100 receives a signal from engine 130 via knock sensor 140, cam angle sensor 150, and crank angle sensor 160.
[0041]
Knock sensor 140 is attached to a cylinder block (not shown) of engine 130 and detects knocking based on vibration of engine 130. For example, a piezoelectric ceramic is used for the knock sensor 140, but is not limited thereto.
[0042]
Cam angle sensor 150 detects the angle of a camshaft (not shown) and transmits a signal for recognizing the cylinder of engine 130 to engine ECU 100.
[0043]
Crank angle sensor 160 detects the angle of a crankshaft (not shown) and transmits a signal necessary for controlling the ignition timing to engine ECU 100.
[0044]
Engine ECU 100 controls ignition by an ignition coil (not shown) by controlling igniter 170.
[0045]
Engine ECU 100 includes a sensor input processing circuit 102, a cylinder recognition circuit 104, a gate timing setting circuit 106, an ignition timing control circuit 108, a knock sensor abnormality determination circuit 110, a knocking determination circuit 112, and a memory 120. .
[0046]
The sensor input processing circuit 102 processes the signal received from the knock sensor 140 based on a predetermined condition.
[0047]
The cylinder recognition circuit 104 recognizes a cylinder in which combustion is performed in the engine 130 based on a signal received from the cam angle sensor 150. The recognized cylinder information is output to the sensor input processing circuit 102 or the ignition timing control circuit 108.
[0048]
The gate timing setting circuit 106 detects an angle of a crankshaft (not shown) included in the engine 130 based on a signal received from the crank angle sensor 160.
[0049]
The ignition timing control circuit 108 transmits a control signal to the igniter 170 based on a signal processed by another circuit.
[0050]
Knock sensor abnormality determination circuit 110 determines whether knock sensor 140 is abnormal based on signals received from sensor input processing circuit 102 and cylinder recognition circuit 104.
[0051]
The knocking determination circuit 112 determines whether or not the recognized cylinder is knocked based on signals received from the sensor input processing circuit 102 and the cylinder recognition circuit 104. Further, knocking determination circuit 112 outputs an advance angle or delay angle instruction to ignition timing control circuit 108 in order to optimize the ignition timing of engine 130 based on the determination result.
[0052]
The memory 120 stores a predetermined abnormality determination value for each cylinder of the engine 130 as will be described later.
[0053]
The data stored in advance in the memory 120 will be described with reference to FIG. FIG. 2 shows an abnormality determination value for each cylinder that is predetermined for each rotation speed of engine 130. This determination value is determined in advance based on the output characteristics of engine 130 and other operating conditions.
[0054]
With reference to FIG. 3, a control structure of a program executed by the knock sensor abnormality detection device according to the present embodiment will be described based on a flowchart.
[0055]
In step (hereinafter, “step” is represented as S) 302, engine ECU 100 receives a signal from each sensor. In S304, engine ECU 100 processes the received signal based on a predetermined condition. This process includes, for example, a process of removing noise from the signal or a process of smoothing the signal.
[0056]
In S306, engine ECU 100 recognizes a specific cylinder of engine 130 based on the processed signal.
[0057]
In S308, engine ECU 100 acquires a determination value corresponding to the recognized cylinder from the determination values (FIG. 2) stored in memory 120.
[0058]
In S310, engine ECU 100 determines whether the processing result of the signal processed in S304 is below the determination value acquired in S308. When the processing result falls below the determination value (YES in S310), the process proceeds to S312. Otherwise (NO in S310), the process proceeds to S318.
[0059]
In S312, engine ECU 100 increments the abnormality counter by one. This abnormality counter represents the number of times that the processing result exceeds the determination value in S310. This number of times is used as a reference for finally determining that knock sensor 140 is abnormal, as will be described in S314. This can prevent erroneous determination of knock sensor 140 due to, for example, a temporary abnormality in the received signal.
[0060]
In S314, engine ECU 100 determines whether or not the abnormality counter exceeds a predetermined reference value n. When the abnormality counter exceeds reference value n (YES in S314), the process proceeds to S316. Otherwise (NO in S314), the process returns to S302 and the determination process is continued.
[0061]
In S316, engine ECU 100 determines that knock sensor 140 is abnormal. In S318, engine ECU 100 determines that knock sensor 140 is normal.
[0062]
In S320, engine ECU 100 clears the abnormality counter.
In S322, engine ECU 100 outputs the determination result. For example, if it is determined that the knock sensor is abnormal, a signal notifying the abnormality is transmitted to a vehicle diagnostic device (not shown) or a warning light provided in the driver's seat, and the maintenance or inspection of the vehicle is promoted. .
[0063]
The operation of the knock sensor abnormality detection device according to the present embodiment based on the above structure and flowchart will be described.
[0064]
When a signal is input from each sensor to engine ECU 100 (S302), each signal is processed based on a predetermined condition (S304), and a cylinder burning in engine 130 is recognized (S306). When the determination value corresponding to the cylinder is acquired from the memory 120 (S308), when the processed signal falls below the determination value (S310), the abnormality counter is incremented by 1 (S312).
[0065]
When the abnormality counter exceeds reference value n (YES in S314), knock sensor 140 is determined to be abnormal (S316). Thereafter, the determination result is output to a vehicle diagnostic apparatus (not shown) (S322) and recorded as information about the engine 130.
[0066]
As described above, according to the knock sensor abnormality detection device according to the present embodiment, the cylinder is recognized based on the signal received from the sensor, and the knock sensor is abnormal based on the determination value corresponding to the cylinder. Therefore, the accuracy of knock sensor abnormality detection can be improved.
[0067]
<Second Embodiment>
Hereinafter, a second embodiment of the present invention will be described.
[0068]
Note that the hardware configuration of the knock sensor abnormality detection device according to the present embodiment is the same as that of the knock sensor abnormality detection device (FIG. 1) according to the first embodiment, and thus the description thereof will be repeated. Absent.
[0069]
With reference to FIG. 4, the determination value used in the knock sensor abnormality detection device according to the present embodiment will be described. FIG. 4 shows a predetermined determination value for each revolution number of the engine 130 for the representative cylinder. This determination value is stored in the memory 120 in advance. Here, the representative cylinder is a cylinder closest to the knock sensor 140 among a plurality of cylinders constituting the engine 130. In this way, by determining the representative cylinder, it is possible to accurately detect the abnormality of the knock sensor 140.
[0070]
The representative cylinder is not limited to a specific cylinder, and a plurality of cylinders may be set as the representative cylinder. For example, the cylinders on both sides of knock sensor 140 may be set as the representative cylinder. Such setting can be performed based on the position of knock sensor 140 in engine 130.
[0071]
With reference to FIG. 5, the control structure of the program executed by the knock sensor abnormality detection device according to the present embodiment will be described based on a flowchart. In addition, the same number is attached | subjected to the step which performs the process same as the process which concerns on 1st Embodiment, and description about them is not repeated.
[0072]
In S508, engine ECU 100 determines whether or not the cylinder recognized in S306 is a representative cylinder. When the recognized cylinder is the representative cylinder (YES in S508), the process proceeds to S510. Otherwise (NO in S508), the process proceeds to S322.
[0073]
In S510, engine ECU 100 obtains a determination value corresponding to the representative cylinder from memory 120.
[0074]
The operation of the knock sensor abnormality detection device according to the present embodiment based on the above structure and flowchart will be described. The description of the same operation as that according to the first embodiment will not be repeated.
[0075]
A cylinder is recognized based on a signal input to engine ECU 100 from each sensor (S306), and when that cylinder is a representative cylinder (YES in S508), a determination value corresponding to that representative cylinder is stored in memory 120. Is acquired (S510). If the process result falls below this determination value (YES in S310), a predetermined process is executed to determine whether knock sensor 140 is abnormal.
[0076]
As described above, the knock sensor abnormality detection device according to the present embodiment determines knock sensor abnormality only based on a signal received from a predetermined specific cylinder (representative cylinder). It is possible to prevent erroneous detection of the knock sensor by using a signal other than the above. Thereby, abnormality of a knock sensor can be detected accurately.
[0077]
<Modification of Second Embodiment>
Hereinafter, modifications of the second embodiment will be described.
[0078]
With reference to FIG. 6, data used in the knock sensor abnormality detection device according to the present modification will be described. FIG. 6 shows determination values determined for each cylinder set as the representative cylinder. This determination value is stored in the memory 120. A plurality of representative cylinders are defined (representative cylinder 1, representative cylinder 2,...), And a determination value is set for each rotation speed of the engine 130 for each cylinder.
[0079]
It should be noted that the number of revolutions of engine 130 may not be every 500 revolutions as shown in FIG. The representative cylinder can be determined based on the positions of the engine 130 and the knock sensor 140 provided thereon.
[0080]
By using such a determination value, when engine ECU 100 recognizes one of the representative cylinders based on the received signal, it can acquire the determination value corresponding to that representative cylinder from memory 120. Therefore, since the frequency of determining the abnormality of knock sensor 140 is increased compared to the case where only one representative cylinder is defined, the abnormality of knock sensor 140 can be detected at an early stage.
[0081]
As described above, according to the knock sensor abnormality detection device according to the second embodiment of the present invention and the modification thereof, the abnormality of knock sensor 140 is detected based on the information related to the cylinder that is previously determined as the representative cylinder. Thus, the abnormality determination based on the information on the cylinders other than the representative cylinder is not performed. By doing so, it is possible to prevent the determination of the cylinder for which it is not easy to obtain accurate information, and therefore it is possible to accurately detect the knock sensor abnormality.
[0082]
The abnormality counter used in the first embodiment and the second embodiment may be set as a counter common to each cylinder, or an individual counter may be set for each cylinder. Good. As a result, the accuracy of knock sensor abnormality detection performed for each cylinder can be further increased.
[0083]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[Brief description of the drawings]
FIG. 1 is a control block diagram of a vehicle equipped with a knock sensor abnormality detection device according to an embodiment of the present invention.
FIG. 2 is data (part 1) stored in the memory shown in FIG. 1;
FIG. 3 is a flowchart showing a control structure of knock sensor abnormality detection processing according to the first embodiment of the present invention.
4 is data (part 2) stored in the memory shown in FIG.
FIG. 5 is a flowchart showing a control structure of knock sensor abnormality detection processing according to a second embodiment of the present invention.
6 is data (part 3) stored in the memory shown in FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 Engine ECU, 102 Sensor input processing circuit, 104 Cylinder recognition circuit, 106 Gate timing set circuit, 108 Ignition timing control circuit, 110 Knock sensor abnormality determination circuit, 112 Knock determination circuit, 120 Memory, 130 Engine, 140 Knock sensor, 150 Cam angle sensor, 160 crank angle sensor, 170 igniter.

Claims (10)

An apparatus for detecting an abnormality of a knock sensor for detecting knocking of an internal combustion engine having a plurality of cylinders,
Receiving means for receiving a signal from the knock sensor;
Recognition means for recognizing one of the plurality of cylinders as a cylinder in which combustion is performed based on a signal received from a sensor provided in the internal combustion engine;
When the recognized cylinder is a predetermined representative cylinder that is the cylinder closest to the knock sensor among the plurality of cylinders, a predetermined determination value corresponding to the representative cylinder is acquired. Acquisition means;
A determination means for determining whether or not the knock sensor is abnormal based on the signal received from the knock sensor and the acquired determination value only when the recognized cylinder is the representative cylinder. An abnormality detection device for a knock sensor, including:   The knock sensor abnormality detection device according to claim 1, wherein the representative cylinder is a cylinder determined based on a position where the knock sensor is attached to the internal combustion engine. Before SL determination means, when the signal received from the previous SL knock sensor calculates the number of times it is determined that below the obtained determination value exceeds the number of times that the calculated predetermined said knock sensor The knock sensor abnormality detection device according to claim 1, wherein the knock sensor abnormality detection device determines that the abnormality is present. The predetermined determination value is a value determined in plural corresponding to the rotational speed of the internal combustion engine,
The abnormality detection device further includes a rotation speed detection means for detecting the rotation speed of the internal combustion engine,
The acquisition unit according to any one of claims 1 to 3, wherein the acquisition unit acquires a recognized determination value of the one cylinder from the plurality of determined values based on the detected rotational speed of the internal combustion engine. The knock sensor abnormality detection device according to claim 1.   The knock sensor abnormality detection device according to any one of claims 1 to 4, wherein the determination unit determines that the knock sensor is normal when a signal received from the knock sensor exceeds an acquired determination value. . A method for detecting abnormality of a knock sensor for detecting knocking of an internal combustion engine having a plurality of cylinders,
A receiving step of receiving a signal from the knock sensor;
Recognizing one of the plurality of cylinders as a cylinder in which combustion is performed based on a signal received from a sensor provided in the internal combustion engine;
An acquisition step of acquiring a predetermined determination value corresponding to the representative cylinder when the recognized cylinder is a predetermined representative cylinder that is the cylinder closest to the knock sensor among the plurality of cylinders. When,
Only when the recognized cylinder is the representative cylinder, a determination step of determining whether or not the knock sensor is abnormal based on a signal received from the knock sensor and the acquired determination value; Including a knock sensor abnormality detection method.   The knock sensor abnormality detection method according to claim 6, wherein the representative cylinder is a cylinder determined based on a position where the knock sensor is attached to the internal combustion engine. Before SL determination step, when the signal received from the previous SL knock sensor calculates the number of times it is determined that below the obtained determination value exceeds the number of times that the calculated predetermined said knock sensor The knock sensor abnormality detection method according to claim 6, wherein the knock sensor abnormality is determined to be abnormal. The predetermined determination value is a value determined in plural corresponding to the rotational speed of the internal combustion engine,
The abnormality detection method further includes a rotational speed detection step of detecting the rotational speed of the internal combustion engine,
9. The acquisition step according to claim 6, wherein the acquiring step acquires a recognized determination value of the one cylinder from the plurality of determined values based on the detected rotational speed of the internal combustion engine. The knock sensor abnormality detection method according to claim 1.   The knock sensor abnormality detection method according to any one of claims 6 to 9, wherein the determination step determines that the knock sensor is normal when a signal received from the knock sensor exceeds an acquired determination value. .

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