JP2000205096A - Knocking detector for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase an S/N ratio so as to improve knocking detecting accuracy by setting a knocking judging level a value eliminated mechanical vibration noise component and electric noise component from a detected result of knocking detecting means at the time of non-knocking, and judging knocking on the basis of the knocking judging level. SOLUTION: In the case where knocking is detected by an ECU 40, since a peak value of an output signal of a knocking sensor 18 and a back ground level include mechanical vibration noise component NK and electric noise component Nd on the basis of driving of an electric load, those noise components Nk and Nd are eliminated from the peak value of the output signal of the knocking sensor 18 by the CPU, and only vibration component by combustion is taken out. An adapted constant K is multiplied by a value eliminated the noise components Nk, Nd from the back ground level, and a knocking judging level is found out. It is compared whether the vibration component by combustion is larger than the knocking judging level or not, and it is judged whether knocking of an engine 11 is generated or not.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a knock detecting device for an internal combustion engine which detects knocking of the internal combustion engine.

2. Description of the Related Art In an internal combustion engine that compresses an air / fuel mixture and ignites with a spark plug, generally, when a knock sensor detects knocking, the ignition timing is gradually retarded, and when knocking is no longer detected. Feedback control of the ignition timing is performed in which the ignition timing is reversed to optimize the ignition timing.

In such knock detection of the internal combustion engine, the presence or absence of knocking is determined by determining whether the peak value VkPEAK of the output signal of the knock sensor is greater than a knock determination level. The knock determination level is obtained by multiplying the background level BG (output level of the knock sensor when knock does not occur) and the knock determination matching constant K.

[0004]

However, FIG.
As shown in (a) and (b), the peak value VkPEAK of the output signal of the knock sensor and the background level B
G includes a mechanical vibration noise component Nk unrelated to combustion of the internal combustion engine and an electric noise component Nd based on driving of an electric load.
It is included.

Therefore, there is no problem when knocking does not occur in the internal combustion engine as shown in FIG. However, for example, as shown in FIG.
3. When knocking has occurred in the internal combustion engine at T4, knocking at time T3 may not be detected even if knocking at time T3 can be detected. This is because the knock determination level is obtained by multiplying the mechanical vibration noise component Nk and the electric noise component Nd included in the background level BG by a constant. As described above, in the conventional knock detection device, the S / N (signal / noise) ratio is deteriorated, and there is a problem that the accuracy of knock detection is low.

Incidentally, in order to improve the accuracy of knock detection of the internal combustion engine, for example, as shown in Japanese Patent Application Laid-Open No. Hei 6-272607, vibration energy extracted from the knock sensor output via a filter is measured and stored in advance. A technique of subtracting a certain background noise equivalent amount to cancel an unnecessary energy amount such as a mechanical vibration noise component and extracting a knocking vibration component to perform an accurate knocking determination, 5
As disclosed in JP-A-222996, there is disclosed a technique for preventing erroneous detection of knocking by setting a low knock sensor output during fuel cut to a knock determination level when performing engine knock control. Further, as disclosed in Japanese Patent Application Laid-Open No. 6-147079, there is disclosed a technique for surely preventing erroneous ignition timing delay processing due to valve seating noise of a valve train with a variable valve drive mechanism. .

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a knock detection device for an internal combustion engine capable of improving the S / N ratio and detecting knock accurately. It is in.

[0008]

In order to achieve the above object, according to the present invention, there is provided a knock detecting means for detecting a mechanical vibration of an internal combustion engine and outputting a knock signal, and the knock detecting means. A knock determination device that performs knock determination based on a knock signal and a knock determination level of the knock detection device, wherein the knock determination device detects the knock when no knock is detected. The knock determination means removes the mechanical vibration noise component and the electric noise component from the detection result of the knock detection means, and the knock from which the noise has been removed. The gist is to determine knocking based on the determination level.

According to this configuration, the mechanical vibration noise component and the electric noise component are removed from the detection result of the knock detection means, and only the vibration component due to combustion is obtained. The knock determination level is a value obtained by removing the mechanical vibration noise component and the electric noise component from the detection result of the knock detection means when there is no knock, and the knock determination level is also only the vibration component due to combustion. Therefore, by comparing the detection result of the knock detection unit that removes the mechanical vibration noise component and the electric noise component with the knock determination level that removes the mechanical vibration noise component and the electric noise component, the presence or absence of knocking of the internal combustion engine can be accurately determined. Well detected.

According to a second aspect of the present invention, in the knock detection device for an internal combustion engine according to the first aspect, the mechanical vibration noise component is generated when the internal combustion engine is forcibly driven without performing combustion. The gist is a detection result of the knock detection means, and the electric noise component is a detection result of the knock detection means when an electric load is operated without burning the internal combustion engine.

According to such a configuration, the mechanical vibration noise component and the electric noise component can be easily and reliably obtained. The invention described in claim 3 is the invention according to claim 1 or 2
In the knock detection device for an internal combustion engine according to the above, when the internal combustion engine is in a predetermined operating state, updating means for updating the detection result of the knock detection means as a new mechanical vibration noise component and a new electric noise component. The point is to prepare.

According to such a configuration, when the internal combustion engine is brought into a predetermined operation state, the detection result of the knock detection means is updated as a new mechanical vibration noise component and a new electric noise component. Knocking is accurately detected in accordance with the state of use.

[0013]

(First Embodiment) A first embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, an engine 11 as an internal combustion engine includes a cylinder 13 formed in a cylinder block 12, a piston 15 reciprocating vertically in the cylinder 13, a cylinder 13 and a cylinder head. A combustion chamber 16 defined by an upper surface of a piston 15 and a crankshaft 17 which is an output shaft of the engine 11, and a connecting rod 19 for converting a reciprocating motion of the piston 15 into a rotational motion of the crankshaft 17.
And The engine 1 is mounted on the outer wall of the cylinder 13.
A knock sensor 18 is provided as knock detection means for detecting knock 1. A rotation speed sensor 20 for detecting the rotation speed of the crankshaft 17 is provided near the crankshaft 17.

On the other hand, the combustion chamber 1
An intake port 22 and an exhaust port 23 communicating with 6 are provided. In the intake port 22 and the exhaust port 23,
An intake valve 24 and an exhaust valve 25 are provided, respectively.
An intake manifold 26 is connected to the intake port 22, and the inside of the intake manifold 26 is an intake passage 26a. A surge tank 27 is provided in the intake manifold 26, and a fuel injection valve 28 for injecting and supplying fuel to the intake port 22 is provided at an end of the intake manifold 26 on the cylinder head 14 side. . The surge tank 27 is provided with an intake pressure sensor 29 for detecting the intake pressure in the surge tank 27.

Above the cylinder head 14, two camshafts 21a and 21b connected to the crankshaft 17 via a timing belt (not shown) are provided.
Are arranged. Each of these camshafts 21a, 21
b, a variable valve timing mechanism (hereinafter simply referred to as “exhaust VVT”) for varying the opening / closing timing of the exhaust valve 25 is provided at the shaft end of the camshaft 21 b on the exhaust valve 25 side.
30) are provided. The exhaust VVT 30 is driven by hydraulic pressure, and near the exhaust VVT 30
An oil control valve (OCV) 31 for driving the motor is provided.

The cylinder head 14 has a combustion chamber 1
Spark plug 3 for igniting the air-fuel mixture sucked into
2 are provided. An ignition coil 33 and an igniter 34 are electrically connected to the ignition plug 32. The igniter 34 conducts and cuts off current to and from the primary coil of the ignition coil 33 based on an ignition signal output from an electronic control unit (hereinafter, simply referred to as “ECU”) 40. The ignition coil 33 cuts off this primary current. At times, a spark discharge is caused in the spark plug 32 by the high voltage induced on the secondary coil side. That is, the ignition plug 32 ignites according to an ignition signal output from the ECU 40 to the igniter 34.

In the engine 11 having such a structure, four strokes of intake, compression, combustion / expansion, and exhaust are performed in the combustion chamber 16 to obtain the power. That is, first, in the intake stroke, the fuel injected from the fuel injection valve 28 and the intake manifold 26
The mixed gas with the air sucked from the intake port 24 is sucked into the combustion chamber 16 through the intake port 22 by opening the intake valve 24 and moving down the piston 15. Next, in the compression stroke, the piston 15 that has reached the bottom dead center moves upward together with the closing of the intake valve 24. Thereby, the volume of the combustion chamber 16 is reduced, and the mixed gas filled in the combustion chamber 16 is compressed. In the subsequent combustion / expansion stroke, a spark is ignited from the ignition plug 32 at a predetermined ignition timing, and the compressed mixed gas is ignited. As a result, the mixed gas in the combustion chamber 16 explodes, and the piston 15 is pushed down in the direction of the bottom dead center by the combustion expansion of the mixed gas.
Is powered. Then, the mixed gas after combustion is sent out from the exhaust port 23 as exhaust gas with the opening of the exhaust valve 25 at a predetermined timing and the upward movement of the piston 15 in the exhaust stroke.

In the engine 11, the knock sensor 18, the rotation speed sensor 20, the intake pressure sensor 29, and the OCV 31 are provided together with the igniter 34 by the EC.
It is electrically connected to U40. The configuration of the ECU 40 will be described with reference to FIG.

The ECU 40 has a ROM (Read Only Memory).
y) 41, and a predetermined control program and the like are recorded in the ROM 41 thereof. Also, the ECU 40 has a ROM
A CPU 42 for executing arithmetic processing based on various control programs recorded in 41 and a RAM (Random Access Memory) 43 for temporarily storing an arithmetic result of the CPU 42, data input from each sensor, and the like. I have.
Further, the ECU 40 has a backup RAM for storing data to be stored when the engine 11 is stopped.
44.

The CPU 42, the ROM 41, and the RAM
43 and a backup RAM 44 are connected to each other via a bus 45, and the input interface 4
6 and the output interface 47. The input interface 46 is connected to the rotation speed sensor 20, the intake pressure sensor 29, and the knock sensor 18. The output interface 47 is connected to the OCV 31 and the igniter 34. These OCV31
The operation of the igniter 34 is controlled by an output signal output based on a control program executed by the CPU 42. Therefore, the opening / closing timing of the exhaust valve 25 becomes variable by controlling the operation of the OCV 31, and the ignition timing of the ignition plug 32 becomes variable by controlling the operation of the igniter 34.

In the present embodiment, the ECU 40 detects the occurrence of knocking of the engine 11, and when knocking occurs, the occurrence of knocking is prevented by ignition timing control. The ignition timing control is performed by controlling the operation timing of the igniter 34 described above. In the ROM 41 of the ECU 40, in addition to the various control programs as described above, a map indicating a knock determination adaptation constant K for obtaining a knock determination level required to determine whether knocking has occurred in the engine 11 is recorded in advance. Have been. In the knock detection by the ECU 40, the peak value VkPEAK of the output signal of the knock sensor 18 and the background level BG (output level of the knock sensor when knocking does not occur) are not related to combustion in the engine 11. Since the mechanical vibration noise component Nk and the electric noise component Nd based on the driving of the electric load are included, a map indicating the initial mechanical vibration noise component Nk and the initial electric noise component Nd is recorded in the ROM 41 in advance. A map of the mechanical vibration noise component Nk and the electric noise component Nd is recorded for each valve timing of the VVT 30.

To set the initial electric noise component, the ignition switch is turned on in a vehicle equipped with the engine 11 and the output of the knock sensor 18 when the engine 11 is not rotating and various electric loads are driven. The peak value VkPEAK of the signal is used. For setting the initial mechanical vibration noise component, the peak value VkPEAK of the output signal of the knock sensor 18 when the engine 11 is forcibly rotated by a motor or the like without performing combustion in the engine 11 is used. At this time, by changing the valve timing of the VVT 30 to an arbitrary value, an initial mechanical vibration noise component for each valve timing of the VVT 30 is obtained.

The mechanical vibration noise component Nk includes the seating noise of the intake valve 24 and the exhaust valve 25, the slap noise of the piston 15, the friction noise of the piston skirt, and the like. In particular,
In the VVT 30, the seating noise overlaps with the change in the valve timing, and the mechanical vibration noise increases. The electric noise component Nd includes ignition noise at the ignition plug 32, headlamp driving noise, alternator noise, idle speed control valve (ISCV) driving noise, and the like. These mechanical vibration noise components N
k and the electrical noise component Nd are the S / N of the knock sensor 18
(Signal / noise) ratio is deteriorated.

For this reason, the CPU 42 controls the knock sensor 1
By subtracting the mechanical vibration noise component Nk and the electric noise component Nd from the peak value VkPEAK of the output signal of No. 8, only the vibration component due to combustion (VkPEAK-Nk-Nd) is extracted. Further, the CPU 42 multiplies a value (BG-Nk-Nd) obtained by subtracting the mechanical vibration noise component Nk and the electric noise component Nd from the background level BG by the adaptation constant K, thereby obtaining a knock determination level (BG).
−Nk−Nd) * K is determined. Then, the CPU 42 calculates the vibration component (VkPEAK-Nk-N)
d) is the knock determination level (BG-Nk-N)
d) It is determined whether or not knocking has occurred in the engine 11 by comparing whether or not it is larger than * K. That is, the vibration component due to combustion (VkPEAK-Nk-N
If d) is larger than the knock determination level (BG-Nk-Nd) * K, the CPU 42 determines that knocking has occurred, and the vibration component due to combustion (VkPEAK-Nk-Nd).
Is equal to or lower than the knock determination level (BG-Nk-Nd) * K, the CPU 42 determines that there is no knock.

In this embodiment, the engine 1
At the time of the ignition timing retard control of 1, the control (exhaust valve opening retard control) for delaying the timing (open timing) of opening the exhaust valve 25 is also performed. This exhaust valve opening retard control is also performed through the ECU 40. That is, the ECU 40
The opening timing of the exhaust valve 25 is made variable by controlling the operation amount of the exhaust VVT 30 via the OCV 31. In the ROM 41 of the ECU 40, together with various control programs, a map indicating the optimal opening timing of the exhaust valve 25 corresponding to the pressure change in the combustion chamber 16 due to the retard amount during the ignition timing retard control is recorded in advance. CPU42
Calculates the retard amount of the opening timing of the exhaust valve 25 corresponding to the retard amount of the ignition timing with reference to this map. And
The opening timing of the exhaust valve 25 is controlled based on the calculated retard amount. If the opening timing of the exhaust valve 25 is too late, the exhaust valve starts to open after the piston 15 reaches BDC, and consequently the output is reduced. Valve 25 must be opened.

When the operating state of the engine 11 becomes a predetermined operating state, the ECU 40 uses the detection result of the knock sensor 18 as a new mechanical vibration noise component and a new electric noise component at the valve timing of the VVT 30 at that time. Learn and backup RAM as a map of new mechanical vibration noise component and new electrical noise component
Record at 44. More precisely, the difference between the mechanical vibration noise component Nk and the electric noise component Nd recorded in the ROM 41 is recorded as the correction amount of the mechanical vibration noise component and the electric noise component.

The learning of the electric noise component is performed in an operating state where the ignition switch is turned on and the engine 11 is not rotating and various electric loads are driven. The peak value VkPEAK of the output signal of knock sensor 18 at this time is obtained as a new electric noise component. The learning of the mechanical vibration noise component is performed when the vehicle is running downhill, when the fuel is cut, or the like, or when the starter switch is turned on and immediately before the first explosion. In these operating states, there is no combustion of the engine 11 and no vibration component due to the combustion. Therefore, the peak value VkPEAK of the output signal of the knock sensor 18 includes only the updated electric noise component other than the mechanical vibration noise component. By removing the electric noise component from the peak value VkPEAK, a new mechanical vibration noise component corresponding to the valve timing at that time is obtained.

Next, the procedure of the knock determination process in the above-described embodiment will be described with reference to the flowchart shown in FIG. This routine is executed by the R
Based on the control program recorded in the OM 41, the CP
It is repeatedly executed, for example, every predetermined time under the control of U42.

When the ignition switch is turned on, the CPU 42 firstly inputs the peak value VkPEAK of the output signal of the knock sensor 18 and the background level BG in step 61.
In addition to reading the adaptation constant K from the map stored in the ROM 41, the initial mechanical vibration noise component Nk
And the initial electrical noise component Nd.

In the following step 62, the CPU 42 determines whether the electric noise component Nd and the mechanical vibration noise component N
It is determined whether or not the learning mode is k.

(1) The ignition switch is turned on and the engine 11 is not rotating. (2) The starter switch is turned on and immediately before the first explosion.

(3) The fuel is cut off. Then, in the process of step 62, the CPU 42
If it is determined that none of the above conditions (1) to (3) is satisfied, the process proceeds to step 64.

In the process of step 62, the CP
If U42 determines that any one of the above conditions (1) to (3) is satisfied, the process proceeds to step 63. In step 63, the CPU 42 acquires a new mechanical vibration noise component and a new electric noise component based on the peak value VkPEAK of the output signal of the knock sensor 18, and obtains the mechanical vibration noise component Nk and the electric noise component N.
Update d.

In step 64, the CPU 42 determines whether or not the engine 11 is in a knock control area.
In this determination, for example, after the warm-up operation and when the engine speed is 5000 to 6000 rpm, it is determined that the engine is in the knock control region.

In the process of step 64, the CPU 42
Determines that the engine 11 is not in the knock control area,
This processing ends. Further, in the process of step 64, when the CPU 42 determines that the engine 11 is in the knock control region, the process proceeds to step 65.

At step 65, the CPU 42
(VkPEAK-Nk-Nd)> (BG-Nk-Nd)
A knock determination is made based on whether or not * K. In the process of step 65, (VkPEAK-Nk-N
d)> (BG-Nk-Nd) * K, that is, if it is determined that knocking of the engine 11 has not occurred, the process ends.

In the process of step 65, the CP
U42 is (VkPEAK-Nk-Nd)> (BG-N
If (k−Nd) * K, that is, if it is determined that knocking of the engine 11 has occurred, the routine proceeds to step 66. In step 66, the CPU 42 performs ignition timing retard control on the ignition timing calculated based on the output signals of the rotation speed sensor 20 and the intake pressure sensor 29,
This processing ends.

As described in detail above, according to the present embodiment, the following effects can be obtained. In the present embodiment, the vibration component due to combustion is subtracted from the peak value VkPEAK of the output signal of the knock sensor 18 by subtracting the mechanical vibration noise component Nk unrelated to the combustion of the engine 11 and the electric noise component Nd based on the driving of the electric load. (VkPEAK-Nk-Nd) is taken out, and the value (BG−) obtained by subtracting the mechanical vibration noise component Nk and the electric noise component Nd from the background level BG.
Nk-Nd) is multiplied by the adaptation constant K to determine a knock determination level (BG-Nk-Nd) * K. Then, the vibration component due to combustion (VkPEAK-Nk-N
By comparing d) with the knock determination level (BG-Nk-Nd) * K, it is determined whether or not knocking has occurred in the engine 11. Therefore, S / N (signal /
Noise) ratio is improved, and as shown in FIG.
When knocking has occurred in engine 11 at two times T1 and T2, knocking at both times T1 and T2 can be reliably detected, and knock detection can be performed accurately. FIG. 4A shows the engine 11.
Shows a case where knocking does not occur.

In the present embodiment, when the engine 11 enters a predetermined operating state, the mechanical vibration noise component Nk and the electric noise component Nd are learned.
The mechanical vibration noise component Nk and the electrical noise component Nd are also updated in accordance with the aging deterioration associated with the long-term use of No. 1, so that the knock determination level is not affected by the deterioration, and the knock detection accuracy can be kept good. Further, by learning and updating the mechanical vibration noise component Nk and the electric noise component Nd, it is possible to absorb variations in knock determination levels for each knock sensor 18, each engine 11, and each vehicle.

Since the mechanical vibration noise component Nk and the electric noise component Nd are set and updated at each valve timing of the VVT 30, the change of the mechanical vibration noise component due to the change of the seating timing of the exhaust valve 25. And the accuracy of knock determination can be further improved.

(Second Embodiment) Next, a second embodiment in which the present invention is applied to a hybrid vehicle having two types of prime movers, such as an engine and an electric motor, and switching between the prime movers according to the running state. Will be described with reference to FIG.

As shown in FIG. 5, a crankshaft 72, which is an output shaft of an engine 71 mounted on a hybrid vehicle, is connected to wheels 76 via a power split device 73, a transmission 74, and an axle shaft 75. . When the rotation of the crankshaft 72 is transmitted to the wheels 76 by the power split device 73 and the like, the wheels 76 rotate and the hybrid vehicle runs.

The crankshaft 72 of the engine 71 is
It is also connected to a generator 78 via a power split device 73. When the rotation of the crankshaft 72 is transmitted to the generator 78 via the power split device 73, the generator 78
Generates power. Further, the generator 78 has a function as a starter motor of the engine 71, and forcibly rotates the crankshaft 72 when the engine 71 is started.

The generator 78 is connected to a power converter 79, and the power converter 79 is connected to a battery 80 and a motor 81.
It is connected to the. The electric motor 81 is connected to the transmission 74.
And a wheel 76 via an axle shaft 75. The electric motor 81 is driven by power supply from the generator 78 and the battery 80. When the rotation of the electric motor 81 is transmitted to the wheels 76 and the wheels 76 rotate, the hybrid vehicle starts running. Therefore, the hybrid vehicle according to the present embodiment includes the engine 71 and the electric motor 81.
And two types of prime movers
And it runs by the electric motor 81.

A knock sensor 77 similar to the knock sensor 18 of the first embodiment is attached to a cylinder block of the engine 71. The output signal of knock sensor 77 is supplied to ECU 8 similar to ECU 40 of the first embodiment.
5 is output.

In the hybrid vehicle thus constructed, the ROM provided in the ECU 85 has a map indicating the adaptation constant K for determination, a map indicating the initial mechanical vibration noise component Nk and the initial electric noise component Nd. Are recorded in advance. The learning of the mechanical vibration noise component Nk and the electric noise component Nd is performed by the knock sensor 7 during the cranking of the engine 71 by the generator 78.
7 is obtained based on the peak value of the output signal.

Therefore, in this embodiment, the mechanical vibration noise component Nk and the electric noise component Nd can be easily obtained. The embodiment of the present invention may be modified as follows.

In an engine having no VVT 30, the learning of the mechanical vibration noise component and the electric noise component in the above embodiment is performed, and the detection result of the knock sensor and the engine speed (from cranking to red zone)
Learn the correlation with. Then, the mechanical vibration noise Nk at another engine speed may be estimated based on the mechanical vibration noise Nk when the engine is cranked in a certain vehicle.

No ignition, ignition (no knock),
And the difference between the frequency components of the signals input to the knock sensor in the three cases of ignition and knock (with knock),
Set the frequency with the largest signal level difference to the knock sensor frequency.

Next, other technical ideas that can be understood from the above embodiments will be described. The knock detection device for an internal combustion engine according to claim 3, wherein the internal combustion engine is mounted on a hybrid vehicle including both an electric motor as a prime mover and an internal combustion engine cranked by a starter, wherein the mechanical vibration noise is reduced. A knock detection device for an internal combustion engine, wherein a component and an electric noise component are detection results of the knock detection means when the starter cranks the internal combustion engine.

According to this configuration, the mechanical vibration noise component and the electric noise component can be easily obtained.

[0053]

According to the first to third aspects of the present invention, S
/ N ratio can be improved, and knock detection can be performed with high accuracy.

According to the second aspect of the present invention, it is possible to easily and reliably acquire the mechanical vibration noise component and the electric noise component. According to the invention described in claim 3,
When the internal combustion engine enters a predetermined operating state, the mechanical vibration noise component and the electric noise component are updated, so that knock detection can be accurately performed according to the internal combustion engine and according to its use state.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view and a block diagram showing an engine according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an electrical configuration of an ECU according to the embodiment.

FIG. 3 is a flowchart showing a knock determination process according to the embodiment.

FIG. 4 is an explanatory diagram showing an operation of knock detection.

FIG. 5 is a schematic diagram showing a drive system of a hybrid vehicle according to a second embodiment.

FIG. 6 is an explanatory view showing the operation of a conventional knock detection.

[Explanation of symbols]

11: engine as internal combustion engine, 13: cylinder, 1
5 piston, 16 combustion chamber, 17 crankshaft, 18 knock sensor, 20 rotation speed sensor, 21
a, 21b: camshaft, 25: exhaust valve, 29: intake pressure sensor, 30: exhaust VVT (variable valve timing mechanism), 40: electronic control unit (ECU).

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G022 AA00 BA01 CA01 CA09 DA02 EA02 EA10 FA01 FA03 FA04 FA05 FA08 GA00 GA05 GA07 GA12 GA13 3G084 AA00 BA17 CA01 CA04 DA04 DA20 EA01 EA11 EB12 EB17 EB20 EC02 EC03 FA13 FA19 FA25 FA36 FA36

Claims (3)

[Claims] 1. Knock detecting means for detecting mechanical vibration of an internal combustion engine and outputting a knock signal, and knock determining means for determining knocking based on a knock signal of the knock detecting means and a knock determination level. A knock detection device for an internal combustion engine, comprising: a knock determination unit that sets the knock determination level to a value obtained by removing a mechanical vibration noise component and an electrical noise component from a detection result of the knock detection unit when there is no knock. A knock detection device for an internal combustion engine that performs knock determination based on a value obtained by removing the mechanical vibration noise component and the electric noise component from a detection result of a knock detection unit and a knock determination level from which the noise has been removed. 2. The knock detection device for an internal combustion engine according to claim 1, wherein the mechanical vibration noise component is a detection result of the knock detection means when the internal combustion engine is forcibly driven from the outside without performing combustion. And a knock detection device for the internal combustion engine, wherein the electric noise component is a detection result of the knock detection means when the electric load is operated without performing the combustion of the internal combustion engine. 3. The knock detection device for an internal combustion engine according to claim 1, wherein when the internal combustion engine is brought into a predetermined operation state, the detection result of the knock detection means is used as a new mechanical vibration noise component and a new one. A knock detection device for an internal combustion engine, comprising: an updating unit that updates the electrical noise component.