JPH10159642A - Knocking judging device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suitably judge knocking so as to improve accuracy of judgment in a knocking judging device for an internal combustion engine which can perform stratified burning and so on. SOLUTION: A fuel injection valve 11 is arranged in the peripheral part of the inner wall surface of a cylinder head 4 in the vicinity of the first intake valve 6a and second intake valve 6b of an engine 1, and fuel from the fuel injection valve 11 is ejected directly to the inside of an air cylinder 1a. Also, a knock sensor 63 for detecting the knocking of the engine 1 is attached to the cylinder block 2 of the engine 1. In case that stratified burning is executed, a combustion speed is increased considerably in comparison with a case that homogenous combustion is executed, therefore, timing that knocking can occur is also hastened. On the contrary, in case that stratified burning is executed, an electronic control device (ECU) 30 sets a knocking judging period to an early time. Therefore, a judging period can be justified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a knocking determination device for an internal combustion engine, and more particularly, to stratified combustion,
The present invention relates to a knocking determination device for an internal combustion engine including a swirl control valve.

[0002]

2. Description of the Related Art In a conventionally used engine, fuel from a fuel injection valve is injected into an intake port, and a homogeneous mixture of fuel and air is supplied to a combustion chamber in advance. In such an engine, an intake passage is opened and closed by a throttle valve linked to an accelerator operation, and by this opening and closing, the amount of intake air supplied to a combustion chamber of the engine (consequently, a gas mixture in which fuel and air are homogeneously mixed). ) Is adjusted, thereby controlling the engine output.

[0003] However, in the technique based on the so-called homogeneous combustion described above, a large intake negative pressure is generated in accordance with the throttle operation of the throttle valve, and the pumping loss increases to lower the efficiency. On the other hand, by reducing the throttle of the throttle valve and supplying fuel directly to the combustion chamber, a combustible mixture is present near the ignition plug, and the air-fuel ratio of the portion is increased,
There is known a so-called "stratified combustion" technique for improving ignitability. In this technology, when the engine is under a low load, the injected fuel is unevenly supplied around the spark plug, and the throttle valve is opened almost fully to perform stratified combustion. Thereby, the pumping loss is reduced, and the fuel efficiency is improved.

[0004] When such "stratified combustion" is performed or when lean combustion is performed, a swirl may be formed in the mixture of the injected fuel. That is, a swirl control valve (SCV) is provided in the intake port, and the intensity of the swirl (swirl) is controlled by adjusting the opening of the SCV. As a result, the combustibility is improved with a small fuel supply amount.

Generally, an engine is equipped with a knock control system. That is, a knock sensor is attached to the engine body, and the sensor generates an output voltage according to the vibration. When the output voltage from the knock sensor exceeds the knock determination level, it is determined that knocking has occurred. In this case, the determination of knocking is not always performed, but a determination period is provided only for the time when the engine body vibrates, assuming that knocking has occurred immediately after ignition. That is, in order to prevent erroneous determination of other vibrations, knocking is determined by taking in only the signal caught by the sensor during the determination period (see Japanese Patent Application Laid-Open No. 58-158).
No. 2467).

[0006]

However, when the above-mentioned conventional technology (knock control system) is applied to an engine capable of performing the above-described stratified combustion or an engine having an SCV, the following problems occur. Can occur. That is, when stratified combustion is performed or when the SCV is closed and the swirl intensity increases, the combustion speed becomes considerably higher than that of general homogeneous combustion. Therefore, knocking may occur earlier, and knocking may not be detected properly within a predetermined determination period.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a knocking determination apparatus for an internal combustion engine capable of performing stratified combustion or the like so that knocking can be properly determined. It is an object of the present invention to provide a knocking determination device for an internal combustion engine that can improve determination accuracy.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, as shown in FIG. 1, a knock detecting means M2 for detecting knocking of the internal combustion engine M1, A knock determination means M3 for determining that knock has occurred in the internal combustion engine M1 when the detection result of the knock detection means M2 exceeds a predetermined determination level;
3. In the knocking determination device for an internal combustion engine that performs the determination of knocking according to No. 3 only within a predetermined determination period, the combustion speed of the internal combustion engine M1 is different from the combustion speed in a reference combustion state. When the combustion speed difference detection means M4 and the combustion speed difference detection means M4 detect that the combustion speed of the internal combustion engine M1 is different from the reference combustion speed in the combustion state. A judgment period changing means M for changing the judgment period
The main point is that 5 is provided.

According to a second aspect of the present invention, in the knocking determination device for an internal combustion engine according to the first aspect, the determination period changing means M5 is controlled by the combustion speed difference detection means M4. The gist of the present invention is to accelerate the determination period when it is detected that the combustion speed is faster than the reference combustion state.

Further, in the invention according to claim 3, in the knocking determination device for an internal combustion engine according to claim 1 or 2, the internal combustion engine M1 can perform homogeneous combustion and stratified combustion. It has a swirl control valve which is opened and closed so that a fuel mixture introduced into the internal combustion engine M1 can form a vortex, and has an EGR valve for adjusting an exhaust gas recirculation amount to the internal combustion engine M1. The gist of the present invention is that it has at least one of the following: being capable of changing the pressure of the fuel supplied to the internal combustion engine M1.

According to a fourth aspect of the present invention, in the knocking determination device for an internal combustion engine according to any one of the first to third aspects, the degree of difference in the combustion speed detected by the combustion speed difference detection means M4. The point is that the larger the is, the greater the degree of change of the determination period changed by the determination period changing means M5 is.

In addition, according to the invention described in claim 5, in the knocking determination device for an internal combustion engine according to any one of claims 1 to 4, the degree of difference in the combustion speed detected by the combustion speed difference detection means M4. The gist is that the determination level is changed according to.

Furthermore, in the invention according to claim 6,
6. The knocking determination apparatus for an internal combustion engine according to claim 5, wherein the determination level is determined by multiplying a detection average value of the knock detection means M2 by a coefficient, and a variation in the coefficient. The point is that the larger the degree of the difference in the combustion speed detected by the combustion speed difference detecting means M4, the greater the degree.

(Operation) According to the first aspect of the present invention, as shown in FIG. 1, knocking of the internal combustion engine M1 is detected by the knock detection means M2, and the detection result exceeds a predetermined determination level. Knocking determination means M
In 3, it is determined that knocking has occurred in the internal combustion engine M1. Further, the knocking determination by the knocking determination means M3 is performed only within a predetermined determination period, thereby preventing erroneous determination of other vibrations as knocking.

In the present invention, when it is detected by the combustion speed difference detecting means M4 that the combustion speed of the internal combustion engine M1 is different from the reference combustion speed, the determination period is changed. The determination period is changed by means M5. For this reason, even if the combustion speed fluctuates with the fluctuation of the combustion state and the timing at which knocking occurs fluctuates, the occurrence of knocking can be reliably determined.

According to the second aspect of the present invention, in addition to the operation of the first aspect of the present invention, the determination period changing means M5 is controlled by the combustion speed difference detecting means M4 so that the internal combustion engine M1 is controlled by the combustion speed difference detecting means M4. When it is detected that the combustion speed is higher than the reference combustion speed, the determination period is advanced. Therefore, even if knocking occurs earlier, the occurrence of knocking can be reliably determined.

Further, according to the third aspect of the present invention,
In addition to the effects of the first and second aspects of the invention, the following effects are achieved. That is, when the internal combustion engine M1 can perform the homogeneous combustion and the stratified combustion, the combustion speed when the stratified combustion is performed is higher than that when the homogeneous combustion is performed. When the internal combustion engine M1 has a swirl control valve that opens and closes so that the fuel mixture introduced into the internal combustion engine M1 can form a vortex, when the swirl control valve is closed, the intensity of the vortex increases. And the burning rate increases. Further, the internal combustion engine M1
EGR for adjusting the amount of exhaust gas recirculated to the internal combustion engine M1
When a valve is provided, the combustion speed increases due to the decrease in the EGR amount. In addition, when the internal combustion engine M1 is capable of changing the pressure of the fuel supplied to the internal combustion engine M1, the atomization is improved and the combustion speed is increased by increasing the fuel pressure. As described above, even when a difference occurs in the combustion speed, occurrence of knocking can be reliably determined.

In addition, according to the invention described in claim 4,
In addition to the effect of the invention according to claims 1 to 3, the degree of the change of the determination period changed by the determination period change unit M5 as the degree of the difference in the combustion speed detected by the combustion speed difference detection unit M4 increases. Is made larger. Therefore, the determination period is further optimized, and the accuracy of the determination is improved.

In addition, according to the invention described in claim 5, in addition to the effects of the inventions described in claims 1 to 4, in addition to the above-mentioned effects, the combustion speed difference detecting means M4 determines the degree of difference in the combustion speed. The judgment level is changed. Therefore, the average value detected by knock detection means M2 differs due to the difference in combustion speed. However, the determination level is optimized accordingly, and the accuracy of the determination is improved.

Further, in the invention according to claim 6,
In addition to the effect of the invention according to claim 5, the determination level is determined by multiplying a detection average value of the knock detection means M2 by a coefficient, and the variation of the coefficient is determined. The degree depends on the combustion speed difference detecting means M4.
The larger the degree of the difference in the combustion speed detected by the above, the larger the value. Therefore, the operation of the invention described in claim 5 is more reliably achieved.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, a first embodiment embodying a knocking determination device for an internal combustion engine according to the present invention will be described.
This will be described in detail with reference to the drawings.

FIG. 2 is a schematic diagram showing a knocking determination device for a direct injection engine mounted on a vehicle in the present embodiment. The engine 1 as an internal combustion engine includes, for example, four cylinders 1a, and the combustion chamber structure of each of the cylinders 1a is shown in FIG. As shown in these drawings, the engine 1 includes a piston in a cylinder block 2, and the piston reciprocates in the cylinder block 2. A cylinder head 4 is provided above the cylinder block 2, and a combustion chamber 5 is formed between the piston and the cylinder head 4. Further, in the present embodiment, four valves are arranged per cylinder 1a, and in the figure, the first intake valve 6a, the second intake valve 6b, the first intake port 7a, and the first intake port 7b in the figure. 2
An intake port, a pair of exhaust valves as 8, and a pair of exhaust ports as 9 are shown.

As shown in FIG. 3, the first intake port 7a
Is composed of a helical intake port, and the second intake port 7
b consists of a straight port extending almost straight.
In addition, an ignition plug 10 is disposed at the center of the inner wall surface of the cylinder head 4. Further, a fuel injection valve 11 as a fuel injection means is disposed around the inner wall surface of the cylinder head 4 near the first intake valve 6a and the second intake valve 6b. That is, in the present embodiment, the fuel from the fuel injection valve 11 is directly injected into the cylinder 1a.

As shown in FIG. 2, the first intake port 7a and the second intake port 7b of each cylinder 1a are respectively connected via a first intake path 15a and a second intake path 15b formed in each intake manifold 15. Connected to the surge tank 16. A swirl control valve (SCV) 17 is arranged in each second intake passage 15b.
These SCVs 17 are connected to a step motor 19 via a common shaft 18. This step motor 19 is connected to an electronic control unit (hereinafter simply referred to as “ECU”).
) Is controlled based on an output signal from the control unit 30.

The surge tank 16 includes an intake duct 20
Is connected to the air cleaner 21 through the intake duct 20.
Inside, a throttle valve 23 which is opened and closed by a separate step motor 22 is provided. That is, the throttle valve 23 of this embodiment is of a so-called electronic control type, and basically, the step motor 22 is
The throttle valve 23 is opened and closed by being driven based on the output signal from 0. By opening and closing the throttle valve 23, the amount of intake air introduced into the combustion chamber 5 through the intake duct 20 is adjusted. In the present embodiment, the intake duct 20, the surge tank 16, the first intake path 15a and the second intake path 15
The intake passage is constituted by b and the like. In addition, near the throttle valve 23, its opening (throttle opening T
A throttle sensor 25 for detecting A) is provided. An exhaust manifold 14 is connected to the exhaust port 9 of each cylinder. The exhaust gas after combustion is discharged to an exhaust duct (not shown) via the exhaust manifold 14.

Further, in the present embodiment, a known exhaust gas circulation (EGR) device 51 is provided. This EG
The R device 51 includes an EGR passage 5 as an exhaust gas circulation passage.
2 and an EGR valve 53 as an exhaust gas circulation valve provided in the middle of the passage 52. EGR passage 5
2 is an intake duct 20 downstream of the throttle valve 23;
It is provided so as to communicate with the exhaust duct. Further, the EGR valve 53 has a built-in valve seat, valve body, and step motor (all not shown), and these constitute an EGR mechanism. The opening degree of the EGR valve 53 fluctuates when the stepping motor intermittently displaces the valve body with respect to the valve seat. And the EGR valve 5
When the valve 3 opens, a part of the exhaust gas discharged to the exhaust duct flows to the EGR passage 52. The exhaust gas is
It flows to the intake duct 20 via the EGR valve 53. That is, a part of the exhaust gas is recirculated into the intake air-fuel mixture by the EGR device 51. At this time, the recirculation amount of the exhaust gas is adjusted by adjusting the opening degree of the EGR valve 53.

The above-described ECU 30 is composed of a digital computer, and is connected to a RAM (random access memory) 3 via a bidirectional bus 31.
2, a ROM (Read Only Memory) 33, a CPU (Central Processing Unit) 34 composed of a microprocessor, an input port 35 and an output port 36. In the present embodiment, the ECU 30 constitutes a knocking determination unit, a combustion speed difference detection unit, and a determination period changing unit.

The accelerator pedal 24 is connected to an accelerator sensor 26A that generates an output voltage proportional to the amount of depression of the accelerator pedal 24.
Accelerator opening ACCP is detected by 6A. The output voltage of the accelerator sensor 26A is input to the input port 35 via the AD converter 37. Similarly, the accelerator pedal 24 has a fully-closed switch 26B for detecting that the depression amount of the accelerator pedal 24 is "0".
Is provided. That is, the fully closed switch 26B
Generates a signal of "1" as the fully closed signal when the depression amount of the accelerator pedal 24 is "0", and generates a signal of "0" otherwise. And the fully closed switch 26
The output voltage of B is also input to the input port 35.

The top dead center sensor 27 generates an output pulse when the first cylinder 1a reaches the intake top dead center, for example.
This output pulse is input to the input port 35. The crank angle sensor 28 has a crankshaft of 30 ° CA, for example.
An output pulse is generated each time the motor rotates, and the output pulse is input to the input port. In the CPU 34, the top dead center sensor 2
7 and the output pulse of the crank angle sensor 28, the engine speed NE is calculated (read).

Further, the rotation angle of the shaft 18 is
The swirl control valve sensor 29 detects the swirl control valve (SCV).
Seventeen opening degrees are detected. The output of the swirl control valve sensor 29 is input to the input port 35 via the A / D converter 37.

At the same time, the throttle sensor 25 detects the throttle opening degree TA. The output of the throttle sensor 25 is input to an input port 35 via an A / D converter 37.

In addition, in the present embodiment, an intake pressure sensor 61 for detecting the pressure (intake pressure PiM) in the surge tank 16 is provided. Further, a water temperature sensor 62 that detects the temperature of the cooling water of the engine 1 (cooling water temperature THW) is provided. The output of both sensors 61 and 62 is also A /
The data is input to the input port 35 via the D converter 37.

Further, a knock sensor 63 as a knock detecting means for detecting knocking of the engine 1 is attached to the cylinder block 2 of the engine 1. The knock sensor 64 is a kind of vibration pickup, and for example, has a characteristic tuned so that the detection capability is maximized when the vibration generated by knocking and the natural frequency of the detection element match and resonate. have. The output of the knock sensor 63 is also input to the input port 35 via the A / D converter 37. The ECU 30 has a gate signal generator, and the generator outputs an open / close signal to the input port 35 based on a signal from the CPU. That is, the detection signal from the knock sensor 63 is input to the input port 35 by the open gate signal from the CPU, and is cut off by the close gate signal. For this reason, a predetermined period is provided for the detection (determination) of knocking.

On the other hand, the output port 36 is connected to each fuel injection valve 11 and each step motor 1 via a corresponding drive circuit 38.
9, 22, the igniter 12 and the EGR valve 53 (step motor). Then, the ECU 30 operates according to a control program stored in the ROM 33 based on signals from the sensors 25 to 29 and 61 to 63 and the like.
The fuel injection valve 11, the step motors 19 and 22, the igniter 12, the EGR valve 53 and the like are suitably controlled.

Next, a program relating to various controls according to the present embodiment in the engine knocking determination device having the above-described configuration will be described with reference to flowcharts. That is, FIG. 4 is a flowchart showing a “determination period setting routine” for setting the knocking determination period in the present embodiment, which is executed by interruption every predetermined crank angle (for example, “180 ° CA”). You.

When the processing shifts to this routine, the ECU
First, in step 101, it is determined whether or not the current combustion state is stratified combustion. Here, whether or not stratified combustion is being performed is determined based on the engine speed NE and the fuel injection amount at that time. If the current combustion state is stratified combustion, the process proceeds to step 102.

In step 102, the timing of outputting a gate open signal (gate open timing) AGAT
Set EO to 5 ° after top dead center. Also, the following step 1
At 03, the timing of outputting the gate close signal (gate close timing) AGATEC is set to 75 ° after the top dead center. Then, the subsequent processing ends once.

On the other hand, when the current combustion state is not stratified combustion (when homogeneous combustion is being executed), step 1 is executed.
Move to 04. In step 104, the timing for outputting the gate open signal (gate open timing) AG
Set ATEO to 15 ° after top dead center. In the subsequent step 105, the gate close signal output timing (gate close timing) AGATEC is set to 90
Set to °. Then, the subsequent processing ends once.

As described above, in the "determination period setting routine", the gate open timing AGATEO and the gate close timing AGA are determined according to the combustion state at that time.
The TEC is set at different times. That is,
When stratified charge combustion is being performed, a period during which knock detection is allowed (determination period) is set earlier than when homogeneous charge combustion is being performed.

Next, the operation and effect of this embodiment will be described. (A) When stratified combustion is performed, the combustion speed is considerably higher than when general homogeneous combustion is performed. For this reason, knocking may occur earlier. In contrast, in the present embodiment,
As described above, when stratified charge combustion is being performed, the knocking determination period is set earlier than when homogeneous charge combustion is being performed. Therefore, even if the time when knocking can occur is advanced, the knocking can be reliably determined. As a result, the knocking can be properly determined, and the accuracy of the determination can be improved.

(Second Embodiment) Next, a second embodiment of the present invention will be described. However, since the configuration and the like of this embodiment are the same as those of the above-described first embodiment, the same members and the like are denoted by the same reference numerals and description thereof is omitted. And, below, the first
The following description focuses on differences from the first embodiment.

This embodiment is different from the first embodiment in that the knocking determination period is changed depending on the opening of the SCV 17 (hereinafter, referred to as “SCV opening” SCVP).

That is, FIG. 5 is a flowchart showing the "determination period setting routine" in the present embodiment, which is executed by interruption every predetermined crank angle (for example, "180 ° CA").

When the process proceeds to this routine, the ECU
First, in step 201, the map (m) shown in FIG. 6 is used based on the SCV opening SCVP at that time.
ApA) is taken into consideration, and a gate open signal output timing (gate open timing) AGATEO is set. Therefore, when the SCV opening SCVP is small and the swirl strength is large, the gate open time AGATEO is
Set early. Conversely, when the SCV opening SCVP is large and the swirl intensity is small, the gate open timing AGATEO is set to a late timing.

In the following step 202, a timing (gate closing timing) AGATEC for outputting a gate closing signal based on the current SCV opening SCVP and also taking into account a map (mapB) shown in FIG.
Set. Therefore, the SCV opening SCVP is small,
If the swirl intensity is high, the gate closing time A
GATEC is set earlier so as to match the gate open time AGATEO. Conversely, when the SCV opening SCVP is large and the swirl strength is small,
The gate close time AGATEC is set to a later time in accordance with the gate open time AGATEO. Then, the ECU 30 once ends the subsequent processing.

As described above, in the "determination period setting routine", the gate opening timing AG is determined according to the current SCV opening SCVP, that is, the swirl intensity.
The ATEO and the gate closing time AGATEC are set at different times. In other words, when the swirl intensity is high, the period during which knocking detection is allowed (determination period) is set earlier than when the swirl intensity is low or no swirl is formed.

Next, the operation and effect of this embodiment will be described. (A) When the swirl strength is high, the combustion speed is considerably higher than when the swirl strength is low or no swirl is formed. For this reason, knocking may occur earlier. On the other hand, in the present embodiment, as described above, when the swirl intensity is large, the knocking determination period is set earlier. For this reason, even if knocking occurs earlier, knocking can be reliably determined, and as a result, knocking can be properly determined, thereby improving determination accuracy. Can be.

(B) In the present embodiment, the greater the swirl intensity, the greater the degree to which the determination period is advanced. Therefore, the determination period is further optimized, and the accuracy of the determination can be further improved.

(Third Embodiment) Next, a third embodiment of the present invention will be described. However, in the configuration and the like of the present embodiment, description of the change of the determination period in the above-described first and second embodiments is omitted. In the following, the contents of control accompanying this will be described.

The present embodiment is characterized in that the content of the determination at the time of knocking determination, particularly the determination level KLEVEL, is changed by the SCV opening SCVP and the like.

FIG. 7 is a flowchart showing a "knock control system (KCS) routine" in the present embodiment, which is executed in the main routine.

When the processing shifts to this routine, the ECU
First, in step 301, the value obtained by A / D conversion of the voltage peak value detected by the knock sensor 63 (peak A / D value VAD) is used as the knock sensor peak value VK.
Set as PEAK.

Next, at step 302, a value obtained by averaging the latest knock sensor peak value VKPEAK is calculated and set as a peak average value VKBG.
In step 303, the determination level coefficient KVAL is calculated based on the current engine speed NE and SCV opening SCVP by referring to a map (mapC) (not shown).

In the following step 304, the judgment level coefficient KVAL is added to the peak average value VKBG.
And the value is set as the determination level KLEVEL.

Further, in step 305, the knock sensor peak value VKPEAK is calculated in step 304.
It is determined whether or not the value exceeds the determination level KLEVEL set in. And the knock sensor peak value VKPEAK
Exceeds the determination level KLEVEL, it is determined that knocking has occurred, and the routine proceeds to step 306.

In step 306, knocking occurrence flag XKNOCK is set to "ON". And
Thereafter, the processing is temporarily terminated. On the other hand, if knock sensor peak value VKPEAK does not exceed determination level KLEVEL, it is determined that knocking has not occurred, and in step 307, knocking occurrence flag XKNOCK is set to “OFF”. Then, the subsequent processing ends once.

As described above, in the "KCS routine", the determination level KLEVEL is determined by the peak average value VK.
It is determined by multiplying BG by the judgment level coefficient KVAL. The determination level coefficient KVAL is determined based on the engine speed NE and the SCV opening SCVP at that time.

Next, the operation and effect of this embodiment will be described. (A) As described above, when the swirl intensity is high, the combustion speed is considerably higher than when the swirl intensity is low or no swirl is formed. In addition, when the combustion speed increases, the vibration of the engine 1 also increases, and the peak average value VKBG also increases. On the other hand, in the present embodiment, the determination level coefficient KVAL and, consequently, the determination level KLEVEL are changed according to the different degrees of the combustion speed, that is, according to the SCV opening SCVP. Therefore, the peak average value VKBG also fluctuates due to the difference in the combustion speed. However, the determination level KLEVEL is optimized accordingly, and the determination accuracy can be further improved.

(B) In the present embodiment, not only the SCV opening SCVP but also the engine speed NE is taken into consideration. Therefore, a further determination level KLE
VEL can be optimized and the determination accuracy can be improved.

The present invention is not limited to the above embodiments, and may be configured as follows, for example. (1) In the first embodiment, the SCV is used in the second embodiment based on whether or not the stratified combustion is performed.
Although the determination period is changed based on the opening SCVP, the determination period may be changed based on another operating state in which the combustion speed fluctuates. The operating state includes, for example, the degree of the EGR amount and the magnitude of the fuel pressure. For example, as the EGR amount increases, the combustion speed increases, and as the fuel pressure increases, atomization improves and the combustion speed increases. As described above, even when there is a difference in the combustion speed, it is possible to reliably determine the occurrence of knocking by applying the above processing contents.

(3) In the above embodiment, the present invention is embodied in the in-cylinder injection type engine 1. However, the present invention is embodied in a so-called general stratified combustion or weak stratified combustion type. You may. For example, the intake ports 7a, 7b
Of the type which injects toward the back side of the umbrella portion of the intake valves 6a and 6b. Although a fuel injection valve is provided on the intake valves 6a and 6b side, a type in which fuel is injected directly into the cylinder bore (combustion chamber 5) is also included. Further, the present invention can be embodied in an engine having an SCV 17 capable of performing lean burn.

(4) Further, in each of the above embodiments, the present invention is embodied in the case of the gasoline engine 1 as the internal combustion engine. However, the present invention can also be embodied in the case of a diesel engine or the like.

[0063]

As described in detail above, according to the present invention,
The knocking determination device for an internal combustion engine capable of performing stratified combustion or the like has an excellent effect that knocking can be properly determined and thus the accuracy of the determination can be improved.

[Brief description of the drawings]

FIG. 1 is a conceptual configuration diagram showing a basic concept of the present invention.

FIG. 2 is a schematic configuration diagram illustrating an engine knocking determination device according to the first embodiment.

FIG. 3 is an enlarged sectional view showing a cylinder portion of the engine.

FIG. 4 is a flowchart showing a “determination period setting routine” executed by the ECU.

FIG. 5 is a flowchart illustrating a “determination period setting routine” according to the second embodiment.

FIG. 6 is a map showing a relationship between an SCV opening degree and a gate open time and a gate close time.

FIG. 7 is a flowchart illustrating a “KCS routine” executed by an ECU according to the third embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine as an internal combustion engine, 11 ... Fuel injection valve, 1
7 ... swirl control valve, 19 ... step motor, 28 ... crank angle sensor, 29 ... swirl control valve sensor, 30 ... knocking determination means, combustion speed difference detection means and EC constituting determination period changing means
U, 53: EGR valve; 63: Knock sensor as knock detection means.

Claims (6)

[Claims] 1. Knock detection means for detecting knocking of an internal combustion engine, and knocking for determining that knocking has occurred in the internal combustion engine when a detection result of the knock detection means exceeds a predetermined determination level. A knocking determination device for the internal combustion engine, wherein the combustion speed of the internal combustion engine is a reference combustion state. And a combustion speed difference detecting means for detecting that the combustion speed of the internal combustion engine is different from a combustion speed in a reference combustion state. A determination period changing means for changing the determination period when the knocking is detected. Setting device. 2. The knocking determination device for an internal combustion engine according to claim 1, wherein the determination period changing unit performs combustion in a combustion state in which a combustion speed of the internal combustion engine is a reference by the combustion speed difference detection unit. A knocking determination device for an internal combustion engine, wherein when it is detected that the speed is higher than the speed, the determination period is advanced. 3. The knocking determination device for an internal combustion engine according to claim 1, wherein the internal combustion engine is capable of performing homogeneous combustion and stratified combustion, and a fuel mixture introduced into the internal combustion engine is provided. A swirl control valve that is opened and closed so as to form a vortex; an EGR valve for adjusting an exhaust gas recirculation amount to the internal combustion engine; and a supply to the internal combustion engine. An apparatus for determining knocking of an internal combustion engine, comprising at least one of those capable of changing the pressure of fuel. 4. The knocking determination device for an internal combustion engine according to claim 1, wherein the degree of difference in the combustion speed detected by the combustion speed difference detection means is changed by the determination period change means. The knocking determination device for an internal combustion engine, wherein the degree of the change of the determination period is increased. 5. The knocking determination device for an internal combustion engine according to claim 1, wherein the determination level is changed according to a different degree of the combustion speed detected by the combustion speed difference detection means. A knocking determination device for an internal combustion engine, characterized in that: 6. The knocking determination device for an internal combustion engine according to claim 5, wherein the determination level is determined by multiplying a detection average value of the knock detection unit by a coefficient, and The knocking determination device for an internal combustion engine, wherein the degree of the change in the coefficient increases as the degree of the difference in the combustion speed detected by the combustion speed difference detection means increases.