JPH0385353A - Abnormality detector of internal combustion engine - Google Patents

Abstract

PURPOSE:To improve accuracy of abnormality judgement by calculating maximum frequency distribution of a knocking signal in the case that the frequency distribution is judged to be less than a specified value, and judging that a knocking controller is abnormal. CONSTITUTION:In a knocking controller M4, mechanical vibration of an internal combustion engine M1 is detected by a knocking signal detection means M2. Detection of knocking generation or control of the knocking generation is performed by a knocking control means M3 based on the detected knocking signal. In this case, a frequency distribution calculation means M5 which calculates the maximum frequency distribution of the knocking signal from the knocking signal detection means M2 is provided. Whether calculated frequency distribution is less than a specified value or not is judged by a distribution judgement means M6. In the case maximum frequency distribution of the knocking signal is less than the specified value, abnormality of the knocking controller M4 is judged by a abnormality judgement means M7.

Description

Detailed Description of the Invention Wataru Otsutachi [Field of Industrial Application] The present invention relates to a device for detecting an abnormality occurring in a knocking control device of an internal combustion engine.

[Prior Art] Conventional As a knocking control device for an internal combustion engine, a knock sensor detects mechanical vibrations generated due to abnormal combustion in the engine as an electrical signal, and the amplitude of this electrical signal reaches a predetermined determination level. (Knock judgment level)
When it exceeds 1:.

A device is used to determine that knocking has occurred, and this device [1] Based on the above determination, the knocking control device was controlling the occurrence of knocking by adjusting the ignition timing, etc. If an abnormality occurs (Part 1), it may become difficult to detect knocking, making it impossible to properly suppress knocking, resulting in severe knocking in the engine, and in some cases, damage to the engine. To detect abnormalities in knocking control devices such as this, which could cause damage, 1:
Conventionally, various abnormality detection methods and abnormality detection devices for knocking control devices have been proposed. For example (e) A device that determines that there is an abnormality in the knocking control device when the output value of the knock signal is less than a predetermined value (abnormality determination level) (Jikkosho 6
0-30473) or a predetermined signal level obtained by integrating the knock signal and an abnormality judgment level proportional to the engine rotation speed, and when the signal level becomes below the abnormality judgment level, knocking is detected. A method of determining that the control device is abnormal (see Japanese Patent Laid-Open No. 19964/1983) is known.

[Problems to be Solved by the Invention] However, the above prior art +1. , If the knock signal is below the abnormality determination level, it is determined that there is an abnormality in the knock control device, so if the knock signal is still insufficient, it is determined that there is an abnormality in the knock sensor, wire harness, or input. When a circuit is disconnected, the amplitude of the knock signal decreases, but in some cases, ignition noise or other noise may get onto the input circuit, causing a signal with a large amplitude that exceeds the abnormality determination level to be detected as a knock signal. The above knock sensor,
When a power supply voltage is applied when a wire harness or an input circuit is short-circuited, a voltage exceeding an abnormality determination level may be detected as a knock signal. In this way, even if an abnormality such as a disconnection or short circuit occurs in the knocking control device, the abnormality may not be detected. The purpose is to provide a detection device.

[Means for Solving the Problems] The present invention has been made to achieve the above object (as illustrated in Table 1), the present invention detects mechanical vibrations of the engine body of the internal combustion engine M1 and knocks. Knock signal detection means M2 that outputs a signal; and knock control means M3 that detects the occurrence of knocking or suppresses the occurrence of knocking based on the knock signal outputted by the knock signal detection means M2. An abnormality detection device for an internal combustion engine that detects an abnormality in the device M4, comprising: frequency distribution calculation means M5 for calculating the frequency distribution of the maximum value of the knock signal outputted by the knock signal detection means M2; distribution width determining means M6 for determining whether the width of the frequency distribution is less than or equal to a predetermined width; The gist of this invention is an abnormality detection device for an internal combustion engine, characterized in that it includes abnormality determining means M6 and 3 for determining that there is an abnormality in the knocking control device M4 when it is determined that there is an abnormality in the knocking control device M4.

[Function] The abnormality detection device for an internal combustion engine of the present invention (1) as illustrated in FIG. A knocking signal is output, and the knocking control means M3 detects the occurrence of knocking or suppresses the occurrence of knocking based on the knocking signal.Then, the frequency distribution calculating means M5 detects the knocking output from the knocking signal detecting means M2. Find the frequency distribution of the maximum value of the signal,
Furthermore, the frequency distribution calculation means M is determined by the distribution width determination means M6.
It is determined whether the width of the frequency distribution obtained in step 5 is less than or equal to a predetermined width. Then, when the distribution width determining means M6 determines that the width of the frequency distribution of the maximum value of the knock signal is less than or equal to a predetermined width, the abnormality determining means M6 determines that there is an abnormality in the knocking control device M4.

In other words, if the knocking control device M4 is normal, 1
Since the frequency distribution of the maximum value of the knock signal has a predetermined spread, in the present invention (i), when the width of the frequency distribution of the maximum value of the knock signal is narrower than the predetermined width, knock control device M4 It is determined that there is an abnormality.

[Example] Next, a preferred example of the present invention will be described in detail based on the drawings. FIG. 2 shows a system configuration of an engine abnormality detection device according to a first embodiment of the present invention.

Ugly In the first embodiment, an example will be described in which a knock signal smoothing circuit is not used.

As shown in the figure 1: Engine abnormality detection device 1 (upper
It includes a four-cylinder engine 2 and an electronic control unit (hereinafter simply referred to as ECU) 3 that controls the engine.

On the engine 21, the first cylinder (#1) 11, the second cylinder (#
2) 12, 3rd cylinder (#3) 13, 4th cylinder (#4) 1
4, each cylinder 11. 12. 13°14 (top)
Spark plug 15. 16. 17. 18 are arranged. These spark plugs 15, 16° 17.18 in 1
The high voltage necessary for ignition generated by the igniter 19 equipped with an ignition coil is transferred to a distributor 20 equipped with a camshaft that interlocks with a crankshaft (not shown).
It is distributed and supplied via.

The engine abnormality detection device 1 serves as a detector for the engine 2.
a resonant knock sensor 31 that is disposed in the cylinder block and outputs mechanical vibration as an electrical knock signal;
Built in the distributor 20, a cylinder discrimination signal (G signal) is generated every 1/4 rotation of the camshaft of the distributor 20 (i.e., every 180 degrees of crank angle).
cylinder discrimination sensor 32 and distributor 2 that generate
A rotation angle sensor 33 that also serves as a rotation speed sensor that generates a rotation angle signal (Ne signal) every 1/24 rotation of the camshaft 1:, that is, every 30[@] crank angle, and an intake pipe inside the intake manifold. It includes an intake pipe pressure sensor 34 that measures pressure, and a water temperature sensor 35 that measures the engine temperature from the temperature of the cooling water of the engine 2. The detection signal 1LEctJ3 of each of these sensors is input to 25ECLJ3 to control the engine 2.

E CU 31 companies MPU 3 a, ROM 3
b, RAM3 c, Backup RAM
3d, configured as a logic operation circuit centering on timer 3e Input/output sections 3g, 3h via common path 3f
is connected to perform input/output with the outside.

The knock signal output by the knock sensor 31 has an impedance conversion effect and has a frequency band specific to knocking (
7 to 8 [K day Z]) as a pass band, and a peak hold circuit 3j that holds the maximum amplitude of the knock signal that has passed through the band pass filter circuit 31 according to the control signal of the MPU 3a % MP
The output of the peak hold circuit 3 is A/D converted according to the control signal of U3a, and the A/D conversion end interrupt signal is
A/D converter 3k, input/output port 3 outputting to PU3a
The cylinder discrimination signal (G signal) detected by the MPU3al discrimination sensor 32 (upper buffer 3m, interrupt request signal forming circuit 3n) is transmitted via MPLJ3 as an interrupt signal and rotational speed signal from the input/output boat 3h via the buffer 3p, interrupt request signal forming circuit 3n, and speed signal forming circuit 3q, respectively.
input to a. Furthermore, the detection signal of the intake pipe pressure sensor 34 is inputted to the buffer 3', and the detection signal of the water temperature sensor 35 is inputted to the buffer 3sl; It is input to the MPU 3a from the output port 3h. On the other hand, the MPU 3al outputs a control signal to the drive circuit 3v via the input/output port 3g, and the igniter]9
to control ignition timing.

Ugly Knock Suppression Control (Knock Sensor 31 above)
This is executed by a device configuration (hereinafter referred to as a knocking control device) consisting of an ECU 3, a wire harness connecting them, and the like.

Next 1: The processing of the first embodiment executed by the ECU 3 will be explained based on FIGS. 3 to 7.

First, the knocking detection start time calculation process will be explained based on the flowchart shown in FIG. This knocking detection start time calculation process 1 is executed in response to an interrupt signal generated at each predetermined specific crank angle (top dead center (TDC) in this embodiment).

First, in step 100, a process of reading various data is performed.In subsequent step 110, a process of calculating the upper knocking detection start time t1 is performed.Here,
Knocking detection start time t11 The starting crank angle of the predetermined knocking detection period (in this example, one
For example, l@ATDCIO~20 [”CAI l, detected current crank angle Cθ[”CAI, timer 3e
is calculated based on the current clock value TM. Next, the process proceeds to step 120, where the knocking detection start time t1 calculated in step 110 is set in the register inside the MPU 3a, and then -jJ this process is ended.

From then on, step 10 for each specific crank angle of this process 1
Repeat steps 0 to 120.

Next 1: 0-knocking detection end time calculation process, which describes the knocking detection end time calculation process based on the flowchart shown in FIG. Executed in response to the input signal.

First, in step 200 (top peak hold circuit 3)
The peak hold circuit 3 j IJ starts the peak hold operation of the knock signal through the process of step 200 in which a high level ("1") control signal is output. In the next step 210, the process of reading various data is performed.The next step 220
The process proceeds to step 21, and a process of calculating the knocking detection end time t2 is performed. Here, knocking detection end time t2ft,
The crank angle from the start time to the end time of the predetermined knocking detection period (in this example)
1.60 to 90 ["CAI), the detected current crank angle Cθ["CAI, is calculated based on the current clock value TM of the timer 3e. Proceeding to the subsequent step 230, the knocking detection end time t2 calculated in step 220 is set in the register inside the MPU 3a, and then the present processing is terminated. Afterwards, this process (
Steps 200 to 230 are repeatedly executed each time an interrupt signal occurs.

Next 1: The A/D conversion start process is explained based on the flowchart in FIG. Executed with a signal.

First, in step 300, a process of outputting a high level ("1") control signal to the liA/D conversion circuit 3k is performed. By the process of this step 300, the A/D conversion circuit 3k
m Start A/D conversion of the knock signal. After performing the process of this step 300, this process ends. Thereafter, this process (Table 1) Step 300 is repeatedly executed every time an interrupt signal occurs.

Next, the knocking detection process will be explained based on the flowchart of FIG. This process is performed prior to the main failure detection process shown in FIG. 7, which will be described later, and shows the process of detecting knocking, controlling the ignition timing, and correcting the frequency average value B.

The area average of the frequency distribution regarding this frequency average value B and the amplitude value of the maximum value of the output voltage of the knock signal (knock signal amplitude value a) is shown.Specially, this process; Upper A/D converter 3
It is activated in response to the A/D conversion end interrupt signal (in this embodiment, for example, generated when 10[m5ecl] has elapsed after the start of A/D conversion) output by the A/D conversion end interrupt signal.

First, in step 400, a process of reading various data is performed.Next, in step 405, a process of setting the 1-up A/D conversion value A/D as the knock signal amplitude value a is performed.Next, in step 410 Then, a process is performed to output a peak hold end control signal to the peak hold circuit 3j. That is, a low level ("O") control signal is output to the peak hold circuit 3j of the MPU 3al.

In the following step 415, it is determined whether or not the abnormality determination flag F is the value O. If an affirmative determination is made here, that is, if it is determined that the knocking control device is normal, the process proceeds to step 420; , if the negative judgment is that it is not normal, the process proceeds to step 425.In this step 425, the
The ignition timing retardation correction value θ is set to a safe retardation correction amount 2 that does not cause knocking.

In the above step 420, it is determined whether the knock determination level KXB, which determines the occurrence of knocking, is greater than or equal to the knock signal amplitude value a, and if an affirmative determination is made here, that is, knocking has not occurred (, If it is determined, the process proceeds to step 430, whereas if it is determined to be negative, the process proceeds to step 435.
Proceed to. In particular, the above values include coefficients (in this example, (for example, [
(=2), and the value B is the frequency average value of the above-mentioned knock signal amplitude value a, and is updated sequentially.

Then, in step 430, which is executed when it is determined that no knocking has occurred, the count value of a counter n that counts the number of consecutive times in which no knocking occurs is set to 1.
Determine whether it is 0 or more, and if it is affirmative, step 44
On the other hand, if the determination is negative, the process advances to step 445.

In step 445, which is executed when this knock-free state is less than 10 consecutive ignition cycles, the process proceeds to step 455 after performing a process of adding 1 to the count value of counter n.

On the other hand, if the state without knocking is 10 consecutive ignition cycles
In step 440, which is executed when the retardation correction value θk of the ignition timing is reduced by the crank angle Y, a process of advancing the ignition timing is performed. This value is used in the well-known ignition timing calculation process that is executed at every predetermined crank angle. The basic ignition timing θO is calculated according to the map stored in the
This basic ignition timing θO is corrected by a retardation correction value θ, to calculate a target ignition timing θ·. Therefore, step 440
By processing target ignition timing θ° (friend crank angle Y
The angle is advanced by

In the following step 450 (↓) After performing a process of resetting the counter n to the value O, the process proceeds to step 455.

Furthermore, in step 435, which is executed when knocking occurs, a process of increasing the ignition timing retard correction value θ by the crank angle X, that is, a process of retarding the ignition timing, is performed. Time θ° 1 company Crank angle retarded by X Knocking is suppressed.

Thereafter, the process proceeds to step 455 via step 450.

Next, in step 455, it is determined whether or not the frequency average value B is greater than or equal to the knock signal amplitude value a. If a negative determination is made here, the process proceeds to step 465, where the frequency average value B is set to a value of 1.
is added to perform an increase correction, and the process proceeds to step 475.

On the other hand, if it is determined in step 455 that the frequency average value B is equal to or greater than the knock signal amplitude value a, the process proceeds to step 460, where it is determined whether the frequency average value B is equal to the knock signal amplitude value a. However, if they are equal, the process directly advances to step 475 to perform a failure detection process to be described later. If they are not equal, the value 1 is subtracted from the frequency average value B in step 470 to correct the decrease, and the process advances to step 475.

In other words, if it is determined in steps 455 and 460 that the frequency average value B exceeds the currently measured knock signal amplitude value a, and if the frequency average value B is biased towards the larger knock signal amplitude value a Therefore, in step 470, taking into consideration the current data, the frequency average value B
This is a reduction correction. In addition, the opposite case is 1: when the frequency average value B is lower than the knock signal amplitude value a (
Since this indicates that the frequency average value B is biased toward the smaller knock signal amplitude value a, the frequency average value B is corrected to increase in step 465.

Then, in step 475, a failure detection process is performed, and in step 480, various calculated or updated data are stored in the RAM 3c or backup RAM 3d, and then this process ends. .

Next, step 47, which is the main process of this embodiment, is performed.
The failure detection process No. 5 will be explained based on the flowchart of FIG. 1: Based on the frequency average value B of the maximum value of the knock signal, as shown in Figure 8 0),
A boundary value is set on one side of the frequency distribution, and if the maximum value of the knock signal occurs more than usual in a range smaller than this boundary value b (region A in Fig. 8 (i)), It is determined that there is an abnormality in the
If the frequency distribution does not have a normal spread (for example, the graph shown in Figure 8 (11)), it is determined to be abnormal.

First, in step 500, a coefficient of 1.5 is added to the frequency average value B.
The value multiplied by is set as the boundary value of a predetermined range (width). In the following step 510, the boundary value is set to a predetermined voltage (
For example, corresponding to 10 mV), it is determined whether or not the voltage is equal to or higher than 0 current, and if a positive determination is made, the process proceeds to step 520, while if a negative determination is made, the process proceeds to step 530, where a boundary value of 10 counts is set. Low Reason for setting a guard of 10 counts for this judgment value 1i If the value of A/D is 0 counts, B=Q, so BXl, 5=○ and b=o
This is because when the knock signal amplitude value a = O (the counter q, which will be described later), becomes the value O, making it impossible to detect a failure.

In step 520, it is determined whether or not the boundary value is less than or equal to the knock signal amplitude value a, that is, the knock signal amplitude value a is on the voltage side (
Determine whether or not it has appeared in the mouth area (in FIG. 8(i)),
If an affirmative determination is made here, the process proceeds to step 540, sets the value O to the counter q, and ends the sample processing. On the other hand, when it is determined that the knock signal amplitude value a is within a predetermined range,
The process proceeds to step 550, where an increase correction is performed by adding the value 1 to the counter q, and the process proceeds to step 550. In other words, the counter qI counts the number of times the knock signal amplitude value a appears within a predetermined range.

In step 560, it is determined whether the 1↓ counter q exceeds the value 25, and if it is affirmatively determined that it exceeds, the process proceeds to step 570, where the abnormality determination flag F is set to the value 1,
- End sample processing. On the other hand, if it is determined that the value is lower than the value (as shown in the table), the sample processing ends.

That is, if the knock signal amplitude value a is within the range of the predetermined frequency distribution,
Above: The number of times is added sequentially, and the result is 2
If the knock signal amplitude value a appears within a predetermined range five times in a row (because the spread of the frequency distribution is small, it is determined that the knocking control device is abnormal.On the other hand, if one of the 25 measurements If the knock signal amplitude value a appears outside the predetermined range even when the knock signal amplitude value a appears outside the predetermined range, that is, if the knock signal amplitude value a appears outside the predetermined range by 4% or more of the total , it is determined that the knocking control device is normal.

In addition, considering the case where the knock signal amplitude value a appears on both sides of the frequency average value B, this embodiment detects an abnormality when 2% of the total knock signal amplitude values a appear outside the predetermined range. It is determined that

As described above, the process of the first embodiment (1) determines the state of occurrence of the knock signal amplitude value a, and determines whether the knock signal amplitude value a is
If the knocking control device frequently appears within a predetermined range including the frequency average value B, it is determined that there is an abnormality in the knocking control device. Therefore, even if a short circuit occurs in, for example, the peak hold circuit 3, the power supply voltage is applied, the peak hold value exceeds the abnormality determination level, and conventionally it would not be determined to be abnormal, this embodiment It is possible to reliably detect an abnormality in the knocking control device based on the width of the frequency distribution.As a result, incorrect control of knocking can be prevented, so appropriate knocking suppression control can be performed to prevent engine damage due to frequent knocking. It has the remarkable effect of being able to prevent this from happening.

Next, a second embodiment of the present invention will be explained in detail based on the drawings.This embodiment will be explained in step 475 in FIG.
This is another example of the failure detection process of
Since this is similar to the embodiment, the explanation will be omitted. The main difference between this second embodiment and the first embodiment is that this embodiment judges the width of the frequency distribution on both sides of the frequency average value B, rather than on one side, and If there is a high probability that a knock signal will appear in Table 1, an abnormality is determined.

The failure detection process executed in the second embodiment will be explained based on the flowchart of FIG. 9.

First, in step 600, an increase correction is performed by adding a value of 1 to the counter g that counts the total number of times the knock signal amplitude value a appears, and in step 605, a coefficient of 1 is added to the frequency average value B.
．． Multiply by 5 to set the boundary value on the large amplitude side.

In the following step 610, it is determined whether the [;L boundary value S, is greater than or equal to the knock signal amplitude value a, and if an affirmative determination is made here, the process proceeds to step 615, whereas if a negative determination is made, the process proceeds to step 630. .

In step 615, it is determined that the knock signal amplitude value a is smaller than the boundary value (a).
The value divided by 5 is set as the boundary value b2 on the small amplitude side. In the following step 620, it is determined whether or not the boundary value b2 is less than or equal to the knock signal amplitude value a, and if an affirmative determination is made, the process proceeds to step 625, where a process is performed in which the value 1 is added to the counter q to correct the increase. On the other hand, if the determination is negative, the process advances to step 630.

That is, through the processing of steps 600 to 625, the knock signal amplitude value a falls within a predetermined width range (boundary value s, ~b).
2), and the number of occurrences is counted by a counter q.

Next, in step 630, it is determined whether or not the friend counter g is 100 or more. It is determined whether or not the above is true, and if an affirmative determination is made, the process proceeds to step 640, and on the other hand,
If the determination is negative, the process advances to step 645. That is, through the processing of steps 630 and 635, it is determined whether the knock signal amplitude value a has appeared within a predetermined range with a probability of 96/100 or more.

Then, in step 640, it is determined that the knock signal amplitude value a has appeared with the above probability, and the knocking control device is found to be abnormal. The value 1 is set to the abnormality determination flag F indicating the value 1, and the present processing is terminated. Meanwhile, in step 645 (t,.

In order to start counting from the beginning again, the value O is set in the counter g, and in the following step 650, the value 0 is also set in the counter q.
is set, and this process ends once.

As mentioned above, the processing of the second embodiment (Table
In other words, if it occurs with a probability of 96% or more (see above), it is determined that there is an abnormality in the knocking control device.
Since the abnormality is determined based on the determination of whether the knock signal amplitude value a appears within a predetermined range set around the frequency average value B, even if the output of the knock sensor 31 is 0 or a small output, it is determined that there is an abnormality. Can judge. For example, even if the resolution of the A/D value is low and is only about 2 volts, it is possible to accurately detect an abnormality in the knocking control device. Ugly This eliminates the need for the 10-count guard of the first embodiment.

Furthermore, ignition noise generated when the knock sensor 31 or wire harness etc. is disconnected, that is, a signal that causes erroneous judgment, often appears on the large amplitude side of the knock signal amplitude value a, and appears on the small amplitude side of the knock signal amplitude value a. Since there are few,
As in this example, 1: Boundary values bI on both sides of the frequency average value B
, b2 to determine an abnormality, it is possible to accurately detect a failure even when the number of occurrences of noise is large. Especially in this embodiment, if randomly superimposed noise appears by 2% or more on the large amplitude side of the knock signal amplitude value a, it is considered normal, so based on the characteristics of the device to which this embodiment is applied, It is desirable to appropriately set the percentage (for example, 3% or 5%) as a reference for abnormality determination in advance.

Next 1: A third embodiment of the present invention will be explained.

The major difference between this third embodiment and each of the above embodiments is that this embodiment uses a smoothing circuit (not shown). 3), and thereby the knock signal amplitude value aFL output from the bandpass filter circuit 3 is inputted to the A/D converter 3k via the smoothing circuit. Since this is the same as in the above embodiment, the explanation will be omitted.

That is, in this embodiment, high frequency noise and the like are removed by the smoothing circuit connected in parallel with the peak hold circuit 3 in Table 1, thereby preventing the input of a signal that would cause an erroneous determination. As a result, in addition to the effects of the first embodiment or the second embodiment,
This has the advantage that abnormalities in the knocking control device can be detected more accurately.

This means that the circuitry is usually well shielded, so
Noise is not superimposed when the peak hold circuit 3j is disconnected, but it is known that noise is likely to be superimposed when the knock sensor 31 is broken or the wire harness is disconnected, and the effect of this noise is removed by the smoothing circuit. Therefore, abnormalities in the knocking control device can be accurately detected.

Further 1: Even if the peak hold circuit 3j etc. is short-circuited, in the same manner as in the first and second embodiments described above,
Abnormalities in the knocking control device can be detected.

In this way, there is a remarkable effect that all kinds of failures can be appropriately dealt with and abnormalities in the knocking control device can be accurately detected.

Although several embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and can be implemented in various forms without departing from the gist of the present invention. Of course.

Oita! □ Nijiri As detailed above, the internal combustion engine abnormality detection device 1 of the present invention
(a) Find the frequency distribution of the maximum value of the knock signal, determine whether the width of the frequency distribution is less than or equal to a predetermined width, and when it is determined that the width of the frequency distribution is less than or equal to the predetermined width] Yo
It is determined that there is an abnormality in the knocking control device. Therefore,
Even if the knock control device is disconnected and noise is superimposed, the effect of the noise can be reduced and the accuracy of abnormality judgment can be improved. This has the effect that an abnormality can be accurately detected even when erroneous determination is likely to occur. Further 1: Since failure detection is performed based on the width of the frequency distribution, the influence of variations in the output of the knock sensor and variations in the vibration state of the engine is reduced, and the abnormality determination level can be easily determined. Therefore, the reliability of the abnormality detection device is increased because malfunctions are less likely to occur, and the durability of the internal combustion engine is also improved by effectively executing knocking suppression control based on the detection results.

[Brief explanation of drawings]

Figure 1 shows the content of the present invention conceptually; Figure 2 shows the basic configuration shown in two examples; Figure 2 shows the system configuration of the first embodiment;
@ 5 @ Figures 6 and 7 are flowcharts showing the same control, Figure 8 is a graph explaining the principle of control in the first embodiment, and Figure 9 is a flowchart showing control in the second embodiment. be. 1 2 3 4 5 6 7 Internal combustion engine knock signal detection means Knocking control means Knocking control device Frequency distribution calculation means Distribution width determination means Abnormality determination means Engine abnormality detection device Engine electronic control unit (ECU) a PU knock sensor

Claims (1)

[Claims] 1. Knock signal detection means for detecting mechanical vibrations of the engine body of an internal combustion engine and outputting a knock signal, and knocking detection or detection based on the knock signal output by the knock signal detection means. A frequency distribution for determining the frequency distribution of the maximum value of the knock signal output by the knock signal detection means, in an internal combustion engine abnormality detection device for detecting an abnormality in a knock control device, comprising: a knock control means for suppressing knocking; a calculation means; a distribution width determination means for determining whether the width of the frequency distribution calculated by the frequency distribution calculation means is less than or equal to a predetermined width; and a maximum value of the knock signal determined by the distribution width determination means. Abnormality determination means for determining that there is an abnormality in the knocking control device when the width of the frequency distribution of is determined to be less than or equal to the predetermined width; Device