JP2002188445A - Control system for autoignition/spark ignition type internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine which maintains stable and high efficiency of autoignition combustion, despite deterioration and changes due to time passage, dispersion in production or the like. SOLUTION: A combustion condition detection part 2 is provided with sensors to detect combustion conditions, detects a first parameter correlating to the knocking strength and detects a second parameter correlating to the stability of combustion. An ECU 3 is provided with a first autoignition limit determining part 9 for determining whether it is possible to continue autoignition combustion based on the first parameter, a a second autoignition limit determining part 10 for determining whether it is possible to continue autoignition combustion based on the second parameter, and a combustion pattern determining part 5 for switching combustion styles from autoignition to spark ignition, when the autoignition limit determining parts 9, 10 have determined that it is not possible to continue autoignition combustion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-ignition engine which selectively uses spark ignition combustion and self-ignition combustion depending on operating conditions.
The present invention relates to a control device for a spark ignition type internal combustion engine.

[0002]

2. Description of the Related Art Self-ignition combustion, in which a mixture which has become high temperature and high pressure by compression self-ignites and starts combustion, starts combustion at multiple points in a combustion chamber, so that the combustion speed is high, so that normal spark ignition combustion is performed. In comparison, stable combustion can be achieved even when the air-fuel ratio is lean. For this reason, it is possible to improve the fuel consumption rate, and because the air-fuel ratio is lean, the combustion temperature is reduced. Can also be significantly reduced. If the fuel and air are sufficiently premixed, the air-fuel ratio becomes more uniform, and the NOx Can be reduced.

[0003] In the high-speed, high-load region, normal spark ignition combustion is performed. In the low-speed, low-medium-load region, the combustion mode is switched from spark ignition combustion to self-ignition combustion. , High output, low fuel consumption at low rotation and low medium load, and reduction of NOx.

In the field of a two-cycle type spark ignition type internal combustion engine, in order to eliminate fuel instability at the time of partial load and to reduce HC (unburned hydrocarbon) emission,
A technique that actively utilizes self-ignition combustion in a combustion chamber has been proposed.

For example, Japanese Patent Application Laid-Open No. 7-71279 discloses that a part of the exhaust passage is closed at a low load to increase the residual gas concentration in the cylinder, thereby increasing the cylinder pressure and temperature at the start of the compression stroke. A technique for controlling the combustion timing of self-ignition has been disclosed.

In order to stably cause self-ignition combustion,
It is necessary that the temperature and the pressure of the working gas become higher than a certain level near the compression top dead center. As means therefor, a large amount of EGR gas is used in combination with a high compression ratio as in the above-described conventional example, or simply by increasing the compression ratio, the cylinder temperature and the cylinder pressure become higher than a certain level. Combustion parameters are determined in advance, and control is performed so as to be the parameters according to the load.

Autoignition combustion is strongly affected by combustion parameters. Taking the air-fuel ratio as an example, when the air-fuel ratio becomes richer than the target air-fuel ratio, the combustion becomes sharp and knocking occurs. Further, when the air-fuel ratio becomes leaner than the target air-fuel ratio, combustion becomes unstable, causing deterioration in drivability. Therefore, it is necessary to control each combustion parameter to a target value.

[0008]

However, in such a conventional spark ignition type internal combustion engine which performs self-ignition combustion, a problem arises due to the accumulation of deposits and soot in the combustion chamber in the process of using the internal combustion engine.

If the deposit or soot is deposited on the wall of the combustion chamber, knocking is likely to occur, and the required octane value increases (S
AE Trans Vol. 64, P76, 195
6). For this reason, a predetermined combustion parameter, for example, the degree of throttle of the exhaust passage in the conventional example,
In general self-ignition combustion, the air-fuel ratio, the EGR amount, the compression ratio, and the like are parameters. However, if so-called soot or deposition of deposits occurs, the engine may knock.

Further, if the control parameters of the engine are determined in advance from the relationship between the air-fuel ratio and the generated torque in a state where deposits and soot are deposited by simulating the process of using the engine, new products such as those shipped from a factory can be obtained. In this state, since no deposit or soot is deposited, self-ignition is unlikely to occur, and the combustion of the engine becomes unstable.

As described above, in the conventional example, knocking occurs when deposits and soot are deposited, so that not only the noise caused by knocking is unpleasant, but also engine deterioration due to an increase in thermal load. In addition, there is a problem that the engine may be deteriorated due to an increase in mechanical pressure load.

In commercial engines, the compression ratio may be slightly different for each engine due to production variations and the like. Alternatively, the temperature of the combustion chamber may be different for each engine due to variations in the water jacket of the engine and the like. In such a case, the target combustion parameter differs for each engine, and there is a problem that combustion instability or knocking occurs in an engine having a large variation width.

When one engine is considered, there is a possibility that the compression ratio and the combustion chamber temperature differ for each cylinder for the above-described reason. Even in such a case, there is a problem that a target combustion parameter differs for each cylinder, and combustion instability or knocking occurs in a cylinder having a large variation width.

In a spark ignition engine, a technique described in Japanese Patent Application Laid-Open No. 8-151951 is known as a technique for coping with variations in characteristics of the engine, knock sensor, and the like, changes over time, and the like. According to this technique, the correction value of the knock determination level, the ignition timing correction, and the like are changed based on the detection value of the knock sensor in the steady operation state.

In the self-ignition combustion, there are a case where knocking becomes a problem and a case where combustion stability becomes a problem under operating conditions. Therefore, when the above technology is applied to self-ignition combustion, there is a problem that the combustion parameters cannot be controlled to the target combustion parameters, and the combustion performance such as fuel consumption and emission deteriorates.

In view of the above-mentioned problems, an object of the present invention is to provide a self-ignition / spark ignition type internal combustion engine that uses spark ignition combustion and self-ignition combustion depending on the operating state, regardless of deterioration with time or changes with time. Another object of the present invention is to provide an internal combustion engine capable of stably maintaining the efficiency of self-ignition combustion at a high level.

Another object of the present invention is to provide an internal combustion engine capable of stably maintaining a high degree of self-ignition combustion efficiency even when engine production variation occurs. Another object of the present invention is to improve the fuel efficiency and exhaust gas of the internal combustion engine by expanding the operation range in which the self-ignition combustion operation is performed.

[0018]

According to the first aspect of the present invention,
In order to achieve the above object, control of a self-ignition / spark ignition type internal combustion engine that performs operation by self-ignition combustion in a predetermined self-ignition operation region and performs operation by spark ignition combustion in an operation region outside the self-ignition operation region In the apparatus, the first detection means for detecting a first determination parameter correlated with the knocking intensity, the second detection means for detecting a second determination parameter correlated with the combustion stability, and performing operation by self-ignition combustion A determination means for determining whether the self-ignition combustion can be continued based on the two determination parameters, and a spark from the self-ignition combustion when it is determined that the self-ignition combustion cannot be continued. A switching means for switching a combustion mode to ignition combustion is provided.

According to a second aspect of the present invention, there is provided a control apparatus for a self-ignition / spark ignition type internal combustion engine according to the first aspect, wherein the first detecting means includes a sensor for detecting an in-cylinder pressure. One or more of a sensor that detects an angular velocity of a crankshaft, a sensor that detects vibration of a combustion chamber component, a sensor that detects sound of a combustion chamber component, and a sensor that detects current or voltage due to ions in combustion gas. The gist is to detect knocking intensity or sound vibration intensity as the first determination parameter.

According to a third aspect of the present invention, there is provided a control apparatus for a self-ignition / spark ignition type internal combustion engine according to the first aspect, wherein the second detecting means detects a pressure in the cylinder. One or more of a sensor that detects an angular velocity of a crankshaft, a sensor that detects vibration of a combustion chamber component, a sensor that detects sound of a combustion chamber component, and a sensor that detects current or voltage due to ions in combustion gas. The gist is to detect combustion stability or misfire as the second determination parameter.

According to a fourth aspect of the present invention, there is provided a control apparatus for a self-ignition / spark ignition type internal combustion engine according to the first aspect of the present invention, wherein the judging means comprises: When the first determination parameter exceeds the allowable range in the region, it is determined that continuation of self-ignition combustion is impossible, while the second determination parameter is allowable in the low load side region of the self-ignition operation region. The gist is to judge that continuation of self-ignition combustion is impossible when the temperature exceeds the range.

According to a fifth aspect of the present invention, there is provided a control apparatus for a self-ignition / spark ignition type internal combustion engine according to the first aspect of the present invention, wherein the knocking strength and the combustion intensity are controlled when the self-ignition operation is performed. Knocking intensity control means for changing the first determination parameter closer to a target value by changing a combustion control parameter that affects both the stability, and the knocking intensity control means controls the combustion control parameter by the knocking intensity control means. When the second parameter exceeds a permissible range as a result of the change, it is determined that the self-ignition combustion cannot be continued.

According to a sixth aspect of the present invention, there is provided a control device for a self-ignition / spark ignition type internal combustion engine according to the first aspect of the present invention, wherein the knocking intensity and the combustion intensity are controlled when the self-ignition operation is performed. The apparatus further includes combustion stability control means for changing the second determination parameter closer to a target value by changing a combustion control parameter that affects both the stability and the combustion stability control means. The gist is to judge that the self-ignition combustion cannot be continued when the first judgment parameter exceeds the allowable range as a result of the change of the control parameter.

According to a seventh aspect of the present invention, there is provided a control device for a self-ignition / spark ignition type internal combustion engine according to any one of the first to sixth aspects of the present invention, in order to achieve the above object. Is stored for each operating condition to change the self-ignition operation region during operation.

According to an eighth aspect of the present invention, there is provided a control device for a self-ignition / spark ignition type internal combustion engine according to any one of the first to fourth aspects. The first detection means and the second detection means are configured to detect and the second determination parameter for each cylinder, and the determination means and the switching means are provided for each cylinder. .

According to a ninth aspect of the present invention, there is provided a control apparatus for a self-ignition / spark ignition type internal combustion engine according to the fifth aspect of the present invention, wherein the first determination parameter and the second
The first detection means and the second detection means are configured to detect the determination parameter for each cylinder, and the determination means, the switching means, and the knocking intensity control means are provided for each cylinder. And

According to a tenth aspect of the present invention, in the control device for a self-ignition / spark ignition type internal combustion engine according to the sixth aspect of the present invention, the first determination parameter and the second determination parameter are set differently. The first detection is performed for each cylinder.
The gist of the present invention is that the detection means and the second detection means are configured, and the determination means, the switching means, and the combustion stability control means are provided for each cylinder.

According to an eleventh aspect of the present invention, in the control device for a self-ignition / spark ignition type internal combustion engine according to any one of the eighth to tenth aspects, a combustion mode of a majority of cylinders is provided. When is switched to spark ignition combustion, the gist is that the switching means of the remaining cylinder switches the combustion mode to spark ignition combustion irrespective of the judgment of the judgment means of the cylinder.

[0029]

According to the first aspect of the present invention, the self-ignition operation is performed in the predetermined self-ignition operation region while the operation by the spark ignition combustion is performed in the operation region outside the self-ignition operation region. In the control device for the spark ignition type internal combustion engine, first detection means for detecting a first determination parameter correlated with knocking intensity, second detection means for detecting a second determination parameter correlated with combustion stability, When operating by self-ignition combustion, it is determined that the self-ignition combustion can be continued based on the two determination parameters, and that the self-ignition combustion cannot be continued. Switching means for switching the combustion mode from self-ignition combustion to spark ignition combustion,
The mechanism of the knocking intensity and the combustion stability generated during the self-ignition combustion operation is different.
The self-ignition limit can be determined by detecting the judgment parameter for each of the two self-ignition limits. As a result, there is an effect that the combustion mode can be changed from self-ignition combustion to spark ignition combustion without deteriorating the operability of the engine.

According to the second aspect of the present invention, in addition to the effect of the first aspect, the first detecting means includes a sensor for detecting an in-cylinder pressure, a sensor for detecting an angular velocity of a crankshaft, and a combustion chamber. The sensor includes at least one of a sensor that detects vibration of a constituent member, a sensor that detects sound of a combustion chamber constituent member, and a sensor that detects a current or a voltage due to ions in the combustion gas. Since the knocking intensity or the sound vibration intensity is detected, there is an effect that the knocking intensity limit or the sound vibration intensity limit, which is one of the self-ignition combustion limits during the self-ignition combustion operation, can be accurately predicted.

According to the third aspect of the present invention, in addition to the effect of the first aspect, the second detecting means includes a sensor for detecting an in-cylinder pressure, a sensor for detecting an angular velocity of a crankshaft, and a combustion chamber. The sensor includes at least one of a sensor that detects vibration of a component, a sensor that detects a sound of a combustion chamber component, and a sensor that detects a current or a voltage due to ions in the combustion gas. Since the combustion stability or misfire is detected, there is an effect that the stability limit or misfire limit, which is the other self-ignition combustion limit during the self-ignition combustion operation, can be accurately predicted.

According to the fourth aspect of the present invention, in addition to the effect of the first aspect of the present invention, the determining means may determine that the first determination parameter is within an allowable range in a high load region of the self-ignition operation region. When the second determination parameter exceeds the allowable range in the low load side region of the self-ignition operation region, it is determined that the continuation of the self-ignition combustion is impossible when the value exceeds the predetermined value. Since it was determined that it is impossible, during low load operation, it is possible to accurately predict the stability limit or misfire limit, which is the self-ignition combustion limit occurring during low load operation, while at high load operation,
It is possible to accurately predict a knocking intensity limit or a sound vibration intensity limit, which is a self-ignition combustion limit generated during a high-load operation. As a result, there is an effect that the combustion mode can be changed from the self-ignition combustion to the spark ignition combustion without deteriorating the operability of the engine regardless of the load of the operating condition.

According to the fifth aspect of the present invention, in addition to the effect of the first aspect of the present invention, a combustion control parameter which affects both the knocking intensity and the combustion stability when operating by self-ignition combustion. By changing the first
Knocking intensity control means for bringing the judgment parameter closer to a target value, wherein the judgment means changes the combustion control parameter by the knocking intensity control means so that the second judgment parameter exceeds an allowable range. Since it is determined that continuation of self-ignition combustion is not possible, self-ignition combustion is possible in the current state of the engine even when engine aging, aging, or engine production variation occurs. The operating range can be accurately determined. As a result, there is an effect that the self-ignition combustion region can be maximized, and the fuel efficiency and exhaust of the engine can be improved.

According to the sixth aspect of the invention, in addition to the effects of the first aspect, a combustion control parameter which affects both the knocking intensity and the combustion stability when operating by self-ignition combustion. By changing the second
Further comprising combustion stability control means for bringing the judgment parameter closer to a target value, wherein the judgment means has changed the combustion control parameter by the combustion stability control means, and the first judgment parameter has exceeded an allowable range. Sometimes, it is determined that continuation of self-ignition combustion is impossible, so even if engine aging, aging, or engine production variations occur, self-ignition combustion will not occur in the current engine state. It is possible to accurately determine a possible operating range. As a result, there is an effect that the self-ignition combustion region can be maximized, and the fuel efficiency and exhaust of the engine can be improved.

According to the seventh aspect of the present invention, in addition to the effects of the first to sixth aspects of the present invention, the self-ignition operation region is stored by storing the judgment result of the judgment means for each operation condition. Since the change is made during the operation, the first or second determination parameter is prevented from repeatedly exceeding the allowable range, and there is an effect that the quietness and the operability of the engine can be improved.

According to the eighth aspect of the invention, in addition to the effects of the first to fourth aspects, the first determination parameter and the second determination parameter are detected for each cylinder. Since the first detecting means and the second detecting means are provided, and the determining means and the switching means are provided for each cylinder, when the aging and the aging change between cylinders are different or due to production variation. Even when the combustion performance of each cylinder differs, the self-ignition limit can be accurately determined for each cylinder, and the combustion mode can be switched from self-ignition combustion to spark ignition combustion without deteriorating drivability. There is an effect that can be.

According to the ninth aspect of the present invention, in addition to the effect of the fifth aspect of the present invention, the first detection parameter and the second determination parameter are detected for each cylinder. Means and the second detecting means, and the judging means, the switching means and the knocking intensity control means are provided for each cylinder. Even if the combustion performance of each cylinder differs due to variations,
The operating range in which self-ignition combustion can be performed can be accurately determined for each cylinder. As a result, the self-ignition combustion area of each cylinder can be maximized, and the fuel efficiency and exhaust of the engine can be further improved.

According to the tenth aspect, the sixth aspect is provided.
In addition to the effects of the invention described above, the first detection means and the second detection means are configured to detect the first determination parameter and the second determination parameter for each cylinder, and the determination means And the switching means and the combustion stability control means are provided for each cylinder, so even if the aging and aging changes between cylinders differ, or even if the combustion performance of each cylinder differs due to production variation, The operating range in which self-ignition combustion can be performed can be accurately determined for each cylinder. As a result, the self-ignition combustion region of each cylinder can be maximized, and the fuel efficiency and exhaust of the engine can be improved.

According to the eleventh aspect, according to the eighth aspect,
In addition to the effects of the invention described in claim 10, when the combustion mode of the majority of the cylinders is switched to spark ignition combustion,
Since the switching means for the remaining cylinder switches the combustion mode to spark ignition combustion regardless of the determination by the determination means for the cylinder, there is an effect that control can be simplified.

[0040]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system configuration diagram showing a configuration of a first embodiment in which a control device for a self-ignition / spark ignition type internal combustion engine according to the present invention is applied.

In this embodiment, it is possible to switch between self-ignition combustion and spark ignition combustion in accordance with the operating range. In FIG. 1, an internal combustion engine includes an engine main body 1 and a combustion state detecting unit 2 serving as first detecting means and second detecting means.
, An engine control unit (hereinafter abbreviated as ECU) 3 as a determination unit and a switching unit, and a combustion parameter control unit 4.

The combustion state detecting section 2 is a cylinder pressure sensor that detects a cylinder pressure, a crankshaft angular velocity detector that detects a crankshaft angular velocity, and a sensor that detects vibration of a combustion chamber member. Various sensors, such as a vibration detector, an acoustic detector that detects the sound of the components of the combustion chamber, and an ion detector in the combustion gas that detects the current or voltage due to ions in the combustion gas in the combustion chamber. And constitutes a first detecting means and a second detecting means.

The determination of the self-ignition combustion limit in the ECU 3 may be defined as the self-ignition combustion limit of the engine when the representative cylinder in which the sensor of the combustion state detection unit 2 is installed reaches the self-ignition combustion limit. The self-ignition limit may be detected for each cylinder, and the time when at least one or more cylinders reaches the self-ignition limit may be defined as the self-ignition combustion limit of the engine.

The combustion state detecting section 2 may be provided with a sensor of the first type for directly detecting the state in the cylinder for each cylinder so that the cylinder having reached the self-ignition combustion limit can be determined. Alternatively, a specific cylinder may be set as a representative cylinder and installed only in that cylinder.

Alternatively, as the second type, a type that can determine that at least one cylinder has reached the self-ignition combustion limit may be used.

As an example of the first type, a combustion state is measured by measuring a current or a voltage due to ions in the combustion gas using an in-cylinder pressure sensor for measuring a combustion pressure in a cylinder and an electrode of a spark plug. There is a device for measuring ions in combustion gas that can be diagnosed. The latter is disclosed in, for example,
This is described in detail in Japanese Patent Publication No. 87036.

The second type includes a vibration detector for detecting vibration of a cylinder head and a cylinder block which are members of a combustion chamber, and an acoustic detector for detecting the sound of a cylinder head and a cylinder block which are members of a combustion chamber. vessel,
There is a crankshaft angular velocity detector.

As the vibration detector, a detector conventionally used as a knock sensor can be used. A microphone can be used as the acoustic detector. One vibration detector and one sound detector may be provided in the engine, and the detection result may be detected as the engine's self-ignition limit based on the detection result.

In the case of an in-line four-cylinder engine, for example, two or three detectors are arranged between the cylinders, and a combination of the plurality of detector output levels determines whether a particular cylinder has reached the self-ignition limit. Then, it can be determined that the combustion limit is self-ignition.

The crankshaft angular velocity detector can detect the crankshaft angular velocity by time-differentiating the output signal of the crankshaft angular velocity sensor or measuring the time required for a constant rotational angle. The knocking limit can be determined from the change in the angular velocity, that is, the angular acceleration, and the stability limit can be determined from the rate of change in the angular velocity.

For example, a cylinder having a knock limit or a cylinder having a stability limit can be determined from an angular velocity in a crankshaft rotation phase corresponding to an expansion stroke of each cylinder. As described above, hardware for detecting the combustion state or software such as a detection method is a known technique.

The ECU 3 obtains an operating region based on the load and the engine speed from the accelerator opening and the crank angle sensor signal, and determines whether or not the operating region is a self-ignition operation region. A spark ignition combustion control unit 6 that controls the combustion time, a self-ignition combustion control unit 7 that performs the control during self-ignition combustion, a combustion parameter setting unit 8 that sets various combustion parameters during the self-ignition combustion, and a combustion state detection unit 2. A first self-ignition limit determining unit 9 for determining whether or not a self-ignition combustion limit is determined by determining various sensor output signal levels; a second self-ignition limit determining unit 10; and target combustion for storing various combustion parameters. Parameter storage unit 1
1 is provided.

The self-ignition combustion limit determined by the first self-ignition limit determination section 9 is a knocking intensity limit or a sound vibration (sound / vibration) intensity limit. The self-ignition limit determined by the second self-ignition limit determination unit 10 is a stability combustion limit or a misfire limit.

An example of a determination method of the first and second self-ignition limit determination sections 9 and 10 corresponding to the combustion state detected by the various sensors of the combustion state detection section 2 will be described below. The sensors used for determining the self-ignition combustion limit may be any one of the following sensors or an arbitrary combination of a plurality of sensors.

When the in-cylinder pressure sensor is used, when the frequency exceeding the first peak combustion pressure corresponding to the load or air-fuel ratio stored in advance reaches a predetermined level, it is determined that the knocking intensity limit or the sound vibration intensity limit has been reached. . Alternatively, it is determined that the knocking limit or the sound vibration intensity limit has been reached when the in-cylinder pressure change, that is, the pressure rise rate reaches a predetermined level.

When the stability limit is detected by the sensor, when the frequency of falling below the second peak combustion pressure corresponding to the previously stored load or air-fuel ratio reaches a predetermined level, it is determined that the stability limit or the misfire limit has been reached. judge. Alternatively, it is determined that the stability limit or the misfire limit has been reached when the change in the in-cylinder pressure, that is, the pressure rise rate becomes equal to or lower than a predetermined level.

When the knocking intensity limit or the sound vibration intensity is detected by the crankshaft angular velocity detector, when the change in angular velocity, that is, the angular acceleration reaches a predetermined level, it is determined that the knocking intensity limit or the sound vibration intensity limit is reached.

When the stability limit or the misfire limit is detected by the detector, when the rate of change of the angular velocity reaches a predetermined level, it is determined that the stability limit or the misfire limit is reached. Alternatively, if the frequency at which the angular velocity in the rotational phase corresponding to the expansion stroke of a specific cylinder is smaller than the angular velocity in another rotational phase by a predetermined ratio exceeds a predetermined level, it is determined that the cylinder has reached the stability limit or the misfire limit. I do.

When the knocking intensity limit or the sound vibration intensity limit is detected by the ion measuring device in the combustion gas,
If the frequency at which the peak value of the current waveform of the combustion chamber by the combustion gas ion detector exceeds the first predetermined value exceeds a predetermined level, it is determined that the cylinder has reached the knocking intensity limit or the sound vibration intensity limit.

When the stability limit or the misfire limit is detected by the ion measuring device in the combustion gas, the frequency at which the peak value of the waveform of the current flowing through the combustion chamber by the ion detector in the combustion gas falls below the second predetermined value. If it exceeds the predetermined level, it is determined that the cylinder has reached the stability limit or the misfire limit.

The combustion parameter control unit 4 includes devices such as an ignition timing control device, a fuel injection timing control device, and a fuel injection amount control device, and controls combustion parameters such as an ignition timing, a fuel injection timing, and a fuel injection amount. Is what you do.

FIG. 2 is a diagram showing a configuration of a first embodiment in which a control device for a self-ignition / spark ignition type internal combustion engine according to the present invention is applied. The engine body 1 in the figure includes an intake port 21, an exhaust port 22, a piston 23, an intake valve 2
4, an exhaust valve 25, a crank angle sensor 26, a fuel injection device 27, and a spark plug 28.

The ECU 3 for controlling the engine body 1
As shown in FIG. 1, a combustion pattern determination unit 5, a spark ignition combustion control unit 6, a self-ignition combustion control unit 7, a combustion parameter setting unit 8, and a first self-ignition limit determination unit 9
And a second self-ignition limit determination unit 10 and a target combustion parameter storage unit 11, which are implemented as a microcomputer program.

The ECU 3 determines operating conditions based on an engine speed signal detected by the crank angle sensor 26 and an accelerator opening signal (load) detected by an accelerator opening sensor (not shown), and determines combustion conditions. Judge the pattern.
Further, the fuel injection amount, the fuel injection timing, and the ignition timing are calculated according to the operating conditions. Then, a signal is sent to the fuel injection device 27 and the spark plug 28 based on the calculation result.

Although not shown, an intake system including a throttle valve for adjusting the air amount, an air flow meter for measuring the air amount, an air cleaner, and piping is provided upstream of the intake port 21.

Under such a configuration, in the present embodiment, self-ignition combustion is performed under specific operation conditions of low rotation and low and medium load as shown in FIG. In, spark ignition combustion is performed.

Next, the operation of the present embodiment will be described. FIG. 4 shows a range in which self-ignition combustion is established with respect to the air-fuel ratio. Fuel injection is performed at a time when the angle is sufficiently advanced from the top dead center, and the air-fuel mixture is in a premixed state. As the air-fuel ratio becomes leaner, the combustion stability deteriorates, and the torque fluctuation of the engine increases. For this reason, the stability limit which is a design value as an internal combustion engine or a stability limit which is acceptable as a characteristic of a vehicle equipped with the internal combustion engine is a stability limit value Sth
Becomes the lean limit.

On the other hand, when the air-fuel ratio is made rich, the knocking strength increases. This gives the knocking limit Nt
The air-fuel ratio AFR at h becomes the rich limit. Therefore,
Stability limit air-fuel ratio AFL and knocking limit air-fuel ratio AFR
The air-fuel ratio region surrounded by is the auto-ignition combustion establishment range.
As described above, self-ignition is established only in a limited air-fuel ratio range. Here, the air-fuel ratio A / F has been described as an example as an index representing the ratio of gas to fuel. Residual gas or EG
The same tendency is exhibited when R gas is included, and in this case, the horizontal axis represents the total gas amount including fresh air and burned gas and the fuel amount ratio G / F.

Here, the knocking strength is a parameter defining the self-ignition limit on the A / F side on the rich side.
When a detecting means for detecting the sound vibration intensity is used, the sound vibration intensity may be used. Similarly, although the A / F sets the parameter that defines the lean-side self-ignition limit as stability, if the detection means for detecting engine misfire is used,
It is good also as a misfire limit.

As described above, in the self-ignition combustion, the combustion limit is defined by two determination parameters of the knocking strength and the stability. Therefore, in the present invention, the combustion limit of self-ignition combustion is determined using two determination parameters of knocking strength and stability.

FIG. 5 shows an area for performing the self-ignition limit determination in the first embodiment. In the present embodiment, in the knocking strength determination region near the high load limit of the self-ignition combustion region,
The knocking intensity or the sound vibration intensity, which is the first determination parameter, is determined. If the intensity exceeds a predetermined value, it is determined that the self-ignition combustion cannot be continued, and the self-ignition combustion is switched to the spark ignition combustion. Switch.

On the other hand, in the stability determination region near the low load limit in the self-ignition combustion region, the determination of the combustion stability or misfire as the second determination parameter is performed, and if the combustion stability or misfire exceeds the predetermined value. Then, it is determined that continuation of the self-ignition combustion is impossible, and the self-ignition combustion is switched to the spark ignition combustion.

FIG. 6 shows a main flowchart for controlling the combustion pattern according to the present embodiment. Step 11 (hereafter,
In step S, the engine speed N and the load T are detected. Next, in S12, a combustion pattern is determined from the combustion determination basic map shown in FIG. 3 as to whether the operation region determined by the engine speed N and the load T is the self-ignition combustion region or the spark ignition combustion region outside thereof. If it is determined that spark ignition combustion has been performed, spark ignition combustion control is performed in S14.

If it is determined in S12 that the combustion is self-ignition, a combustion determination is made in S15 based on the self-ignition limit determination. That is, it is determined whether the self-ignition combustion can be continued based on the detection result detected by the combustion state detection unit 2 based on whether or not the self-ignition limit has been exceeded. Can be continued, and if the self-ignition limit is exceeded, the self-ignition combustion cannot be continued and a determination is made to switch the combustion mode to spark ignition combustion.

When the self-ignition is determined in S15, the self-ignition combustion is controlled in S16. If the combustion determination is spark ignition in S15, the process proceeds to S14 to control spark ignition combustion even if self-ignition is performed in the basic map for combustion determination.

FIG. 7 shows a flowchart of the self-ignition limit judgment of this embodiment. First, in S21, the engine speed N and the load T are detected. Next, in S22, the operating region is determined from the map of FIG. 5 based on the engine speed N and the load T. If the operation area is the stability judgment area,
In S23, the stability is detected, and in S24, it is determined whether or not the stability exceeds the stability limit. If the stability limit is exceeded and the judgment is N.P. G. FIG. In the case of, the combustion determination flag is set to spark ignition in S25. In S24, the determination of the stability limit is made by O.D. K. If it becomes, proceed to S26,
The combustion determination flag is set to self-ignition.

If it is determined in S22 that the operation region is other than the stability determination region and the knocking intensity determination region, the process proceeds to S2.
Proceeding to 6, the combustion determination flag is set to self-ignition. S
If it is determined in step 22 that the knocking determination area has been reached, S2
At 7, the knocking intensity is detected. Next, in S28, it is determined whether or not the knocking intensity exceeds the knocking intensity limit. In S28, the judgment is made without exceeding the knocking strength limit.
K. If the answer is S, the combustion determination flag is set to self-ignition in S26. In S28, the knocking strength is determined by N. G. FIG. If the answer is S, the combustion determination flag is set to spark ignition in S29.

By performing the above-described control, it is possible to optimally set the self-ignition combustion region even when there is aging, aging, or production variation of the engine.

Next, a second embodiment will be described. The system configuration and hardware configuration of the control device for a self-ignition / spark ignition internal combustion engine according to the second embodiment of the present invention are the same as the system configuration (FIG. 1) and the hardware configuration (FIG. 2) of the first embodiment.

FIG. 8 shows an area where the self-ignition limit is determined in the second embodiment. In the present embodiment, the self-ignition limit is determined in all the self-ignition combustion regions. For example, as shown in FIG. 8, a region on a higher load side than a certain load value is a knocking intensity determination region for determining a knocking intensity limit, and a region on a lower load side than the load value is a stability for determining a stability limit. This is a determination area.

FIG. 9 is a flowchart of the self-ignition limit judgment according to the second embodiment. The flowchart of the self-ignition limit determination of the second embodiment is almost the same as the flowchart of the first embodiment (FIG. 7), and only different points will be described. In S32, the operation region is determined based on the engine speed N and the load T. As a result of this determination, the process proceeds to S33 for stability detection in the case of the stability determination region, and proceeds to S37 for knock detection in the case of the knocking determination region.

Next, a third embodiment will be described. The system configuration and hardware configuration of the control device for a self-ignition / spark ignition internal combustion engine according to the third embodiment of the present invention are the same as the system configuration (FIG. 1) and the hardware configuration (FIG. 2) of the first embodiment.

FIG. 10 shows an area where the self-ignition limit is determined in the third embodiment. In the third embodiment, the low load region of the self-ignition combustion region is used as a stability determination region for determining the stability limit, and the high load region of the self-ignition combustion region is used for both the knocking limit determination and the stability limit determination. This is the stability and knocking strength determination area to be performed.

FIG. 11 is a flowchart of the self-ignition limit judgment according to the third embodiment. The flowchart of the self-ignition limit determination of the second embodiment is almost the same as the flowchart of the first embodiment (FIG. 7), and only different points will be described. In S42, the operating region is determined based on the engine speed N and the load T. If the operating region is the stability and knocking determination region, the process proceeds to S47, and knocking intensity is detected.

Next, a knocking strength judgment is made in S48.
Judgment of knocking strength is N. G. FIG. If it becomes,
Proceeding to 49, the combustion determination flag is set to spark ignition.
In S48, the knocking strength is determined by O.D. K. If the answer is S, the process proceeds to S50, and the stability is detected. Next, in S51, the determination of the stability limit is made by N.P. G. FIG. In step S49, the combustion determination flag is set to spark ignition in step S49. In S49, the determination of the stability limit is made by O.D. K. In the case of, the flag of the combustion determination is set to self-ignition in S52.

Next, a fourth embodiment will be described. The system configuration and hardware configuration of the control device for a self-ignition / spark ignition internal combustion engine according to the fourth embodiment of the present invention are the same as the system configuration (FIG. 1) and the hardware configuration (FIG. 2) of the first embodiment.

FIG. 12 shows an area where the self-ignition limit is determined in the fourth embodiment. In the fourth embodiment, a high-load region in the self-ignition combustion region is a knocking intensity control region for performing knocking intensity control. FIG. 13 shows a pressure waveform of self-ignition combustion partially using spark ignition combustion performed in a high load region of the self-ignition combustion region. In this example, part of the fuel is spark-ignited and the remaining fuel is self-ignited using the combustion temperature and pressure. By taking such a combustion form, the combustion timing can be controlled by the ignition timing ADV.

FIG. 14 shows the relationship between the knocking intensity and the combustion timing θ50 with respect to the ignition timing ADV. Ignition timing AD
By retarding V, the combustion timing θ50 can be retarded from the top dead center TDC. Combustion timing θ50
Is retarded from the top dead center, combustion is performed when the piston descends, so that the combustion speed is reduced, and the knocking intensity and the sound vibration intensity can be reduced.

FIG. 15 shows the relationship between the stability with respect to the ignition timing ADV and the combustion timing θ50. If the ignition timing ADV is retarded, the combustion timing θ50 is retarded, so that the stability is deteriorated. Thus, the knocking strength and the stability have a trade-off relationship.

FIG. 16 shows a self-ignition combustion region with respect to the A / F and the ignition timing ADV. The auto-ignition combustion region is a region between the knocking strength limit and the stability limit. The higher the load, that is, the richer the A / F, the worse the knocking. Therefore, the ignition timing ADV is retarded to reduce the knocking intensity.
Therefore, the IT range in which the self-ignition combustion is established is narrowed. Therefore, the A / F at which the knocking strength limit and the stability limit overlap is the high load limit at which auto-ignition combustion is established.

In the fourth embodiment, the ignition timing ADV, which is a combustion parameter, is
To control combustion. At that time, the stability is detected, and when the stability limit is reached, the combustion state is switched from self-ignition combustion to spark ignition combustion. By performing such control, it is possible to maximize the range of the self-ignition combustion without increasing the drivability.

FIG. 17 is a flowchart of the self-ignition limit judgment according to the fourth embodiment. In S81, the engine speed N and the load T are detected. In S82, the operating region is determined based on the engine speed N and the load T. When it is determined in S82 that the vehicle is outside the knocking intensity control region from the map of FIG. 12, the process proceeds to S83, and the combustion determination flag is not changed. S
If it is determined in 82 that the knocking intensity control area,
In S84, the knocking intensity is detected. In S85, the knocking strength is determined.

If it is determined in S85 that the knocking intensity is weaker than the target range, ADV is advanced in S86, and the process returns to S84. If it is determined in S85 that the knocking intensity is higher than the target range, the stability is detected in S87. In S88, the stability limit is determined. In S88, the stability is N.P. G. FIG. If it is determined that the load exceeds the high load limit in the self-ignition region, the combustion determination flag is set to spark ignition in S90. In S88, the stability is O. K. If it is determined that the ADV is determined, the ADV is retarded in S89, and the process returns to S84.

If the knocking intensity is within the target range in S85, the process proceeds to S91, and the ADV is not changed. Next, the stability is detected in S92. In S93, the stability is determined. G. FIG. In the case of, the combustion flag is set to spark ignition in S90. In S93, the stability is O. K. When it is determined that the ignition is not performed, the combustion determination flag is set to self-ignition in S94.

Next, a fifth embodiment will be described. The system configuration and the hardware configuration of the control device for a self-ignition / spark ignition internal combustion engine according to the fifth embodiment of the present invention are the same as the system configuration (FIG. 1) and the hardware configuration (FIG. 2) of the first embodiment.

FIG. 18 shows an area where the self-ignition limit is determined in the fifth embodiment. In the fifth embodiment, the high-load region of the self-ignition combustion region is a stability control region for performing stability control. In the fourth embodiment, the knocking limit is controlled, the stability is monitored and detected, and the self-ignition limit is determined. On the other hand, in the fifth embodiment, the self-ignition limit is determined by monitoring the knocking intensity by controlling to the stability limit. Even with such control, the same effects as in the fourth embodiment can be obtained.

FIG. 19 shows a flowchart of the self-ignition limit judgment of the fifth embodiment. In S101, the engine speed N and the load T are detected. In S102, the engine speed N
And the load T is used to determine the operating region. If it is determined in S102 that it is outside the stability control region, the process proceeds to S103,
The combustion determination flag is not changed. If it is determined in S102 that the area is the stability control area, the stability is detected in S104. The stability is determined in S105. If the stability is determined to be better than the target value in S105, A is determined in S106.
The DV is retarded, and the process returns to S104.

If it is determined in step S105 that the stability is lower than the target value, knocking is detected in step S107.
In S108, a knocking limit is determined. In S108, the knocking is N. G. FIG. If it is determined that the load exceeds the high load limit in the self-ignition region, the combustion determination flag is set to spark ignition in S110. In step S108, knocking is performed. K. When it is determined that ADV is advanced in S109, the process returns to S104.

If the stability is within the target range in S105, the process proceeds to S111, and the ADV is not changed. Then S
At 112, the knocking intensity is detected. In step S113, knocking is determined. G. FIG. In the case of S1
At 10, the combustion flag is set to spark ignition. The stability is O. K. If it is determined that the ignition has been performed, the combustion determination flag is set to self-ignition in S114.

Next, a sixth embodiment will be described. The system configuration and hardware configuration of the sixth embodiment of the control device for a self-ignition / spark ignition internal combustion engine according to the present invention are the same as the system configuration (FIG. 1) and the hardware configuration (FIG. 2) of the first embodiment.

The sixth embodiment is different from the fourth embodiment and the fifth embodiment.
When performing the control of the embodiment, the present invention is characterized in that a combustion parameter and a combustion determination flag are learned and stored.

By learning and storing the combustion parameters and the combustion determination flag, the next time the same conditions are met, the storage can be called up and the combustion mode can be optimally selected.

FIG. 20 is a flowchart showing an example of the sixth embodiment in which the combustion parameters and the combustion determination flag are learned and stored in the case of the fifth embodiment. A similar flowchart is used in the case of the fourth embodiment. Only different points from the flowchart of the fifth embodiment (FIG. 19) will be described. If the combustion determination flag is set to spark ignition in S130, the value of the combustion determination flag = spark ignition is stored at the position of the corresponding operating condition on the map of FIG. If the combustion determination is self-ignition in S135, the ADV value, which is a combustion parameter, is stored in the corresponding operating condition position in the map of FIG. 22 in S136, and the combustion determination flag value = self-ignition in S137. It is stored in the position of the corresponding operating condition on the map of FIG.

Next, a seventh embodiment will be described. FIG. 23 shows the system configuration of a seventh embodiment of the control apparatus for a self-ignition / spark ignition internal combustion engine according to the present invention. The hardware configuration of the seventh embodiment is the same as the hardware configuration of the first embodiment (FIG. 2).
Is the same as The seventh embodiment is characterized in that self-ignition limit control is performed for each cylinder.

In FIG. 23, the internal combustion engine of the seventh embodiment has an engine body 1 and a combustion state detecting unit 102 for each cylinder.
, An ECU 3 and a combustion parameter control unit 104 for each cylinder.

The ECU 3 determines a combustion pattern from the accelerator opening and the crank angle sensor signal, a combustion pattern control unit 5 for controlling during spark ignition combustion, and a self-ignition control for performing self-ignition combustion. A combustion control unit 7, a cylinder-specific combustion parameter setting unit 108 for setting various combustion parameters for each cylinder during self-ignition combustion, and various sensor output signal levels of the cylinder-specific combustion state detection unit 102 to determine the self-ignition combustion for each cylinder A cylinder-specific first self-ignition combustion limit determination unit 109 and a cylinder-specific second self-ignition combustion determination unit 110 for determining whether or not the limit is reached, and set values of various combustion parameters in the self-ignition combustion limit are stored for each cylinder. And a target combustion parameter storage unit 111 for each cylinder.

The cylinder-by-cylinder combustion state detecting unit 102 is one or more of an in-cylinder pressure sensor, a crankshaft angular velocity detector, a vibration detector, an acoustic detector, and an ion detector in combustion gas, as in the above-described embodiments. Multiple combinations.

The combustion parameter control unit 104 for each cylinder
Are ignition timing,
One or a combination of a plurality of fuel injection timings and fuel injection amounts.

FIG. 24 shows a control flow according to the seventh embodiment. The control flow of the seventh embodiment is basically the same as the first to sixth embodiments. In the present embodiment,
A four-cylinder engine is described as an example. In S141, a crank angle signal is detected. In S142, cylinder determination is performed. S1
If it is determined at # 42 that the engine is # 1 (first cylinder), the process proceeds to S14.
In step 3, the combustion pattern is determined. This is based on the flowchart (FIG. 6) for determining the combustion pattern described in the first embodiment.
This is performed only for one cylinder. Next, the self-ignition limit is determined in S144. This is the self-ignition limit determination flowchart (FIGS. 7, 9, 11, 15, 17, 19, and 20) described in the first to sixth embodiments.
Is performed only for the # 1 cylinder. In S142, # 2, # 3,
The case where # 4 is determined is the same as # 1.

By controlling in this way, even when the aging and aging changes for each cylinder are different or when the combustion performance of each cylinder is different due to production variation, the operability is not deteriorated, and the self-reliability of each cylinder is maintained. The ignition region can be set optimally.

Next, an eighth embodiment will be described. The system configuration and the hardware configuration of the control device for a self-ignition / spark ignition type internal combustion engine according to the eighth embodiment of the present invention are the system configuration of the seventh embodiment (FIG. 23) and the hardware configuration (FIG. 2).
Is the same as The eighth embodiment is characterized in that when the combustion mode of the majority of the cylinders is spark ignition combustion, the combustion of all cylinders is spark ignition combustion.

FIG. 25 shows a flowchart of control in a case where a four-cylinder engine is used as an example. In the following description, the combustion determination flag of the n-th cylinder is indicated by Fn, and when the combustion determination result of the n-th cylinder is spark ignition, Fn = 1, and when self-ignition is performed, Fn = 0.
And

First, in step S161, a combustion determination flag for the # 1 cylinder is called. In S162, it is determined whether the combustion determination flag is spark ignition. In the case of self-ignition, F1 is set to 0 in S163. If spark ignition is determined in S162, S
At 164, F1 is set to 1. In steps S165 to S176, the same processing is performed for cylinders # 2 to # 4. S17
7 (F1 + F2 + F3 +
It is determined whether or not F4) exceeds 2. If the number of cylinders is two or less, the process proceeds to S178, and the combustion determination flag is not changed.
When there are three or more cylinders, the combustion determination flags of all cylinders are set to spark ignition in S179.

When the present embodiment is applied to an engine other than a four-cylinder engine, when the number of cylinders is n, when the number of cylinders exceeds n / 2, that is, when the majority of the cylinders are spark-ignited, the remaining cylinders are also used. As the spark ignition, all the cylinders are set to the spark ignition operation.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a first embodiment of a control device for a self-ignition / spark ignition type internal combustion engine according to the present invention.

FIG. 2 is a hardware configuration diagram of the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a combustion pattern with respect to an engine speed N and a load T.

FIG. 4 is a diagram illustrating knocking intensity, stability, and combustion timing with respect to an air-fuel ratio during self-ignition combustion.

FIG. 5 is a diagram illustrating a self-ignition limit determination region according to the first embodiment.

FIG. 6 is a flowchart of combustion pattern control according to the first embodiment.

FIG. 7 is a flowchart of a self-ignition limit determination control according to the first embodiment.

FIG. 8 is a diagram illustrating a self-ignition limit determination region according to a second embodiment.

FIG. 9 is a flowchart of a self-ignition limit determination control according to a second embodiment.

FIG. 10 is a diagram illustrating a self-ignition limit determination area according to a third embodiment.

FIG. 11 is a flowchart of self-ignition limit determination control according to a third embodiment.

FIG. 12 is a diagram illustrating a self-ignition limit determination region according to a fourth embodiment.

FIG. 13 is a diagram for explaining an in-cylinder pressure waveform of self-ignition combustion by spark ignition.

FIG. 14 is a diagram illustrating the relationship between knocking intensity and combustion timing θ50 with respect to ignition timing ADV.

FIG. 15 shows the stability with respect to the ignition timing ADV and the combustion timing θ.
It is a figure explaining 50 relations.

FIG. 16 is a diagram illustrating a self-ignition region with respect to an air-fuel ratio A / F and an ignition timing ADV.

FIG. 17 is a flowchart of a self-ignition limit determination control according to a fourth embodiment.

FIG. 18 is a diagram illustrating a self-ignition limit determination region according to a fifth embodiment.

FIG. 19 is a flowchart of a self-ignition limit determination control according to a fifth embodiment.

FIG. 20 is a flowchart of a self-ignition limit determination control according to a sixth embodiment.

FIG. 21 is a diagram showing a combustion control flag map for learning control.

FIG. 22 is a diagram showing an ADV map for learning control.

FIG. 23 is a system configuration diagram of a seventh embodiment of the present invention.

FIG. 24 is a control flowchart of the seventh embodiment.

FIG. 25 is a flowchart of control according to the eighth embodiment.

[Description of Signs] 1 Engine main body 2 Combustion state detection unit 3 ECU 4 Combustion parameter control unit 5 Combustion pattern determination unit 6 Spark ignition combustion control unit 7 Self-ignition combustion control unit 8 Combustion parameter setting unit 9 First self-ignition combustion limit Judgment unit 10 Second self-ignition combustion limit judgment unit 11 Target combustion parameter storage unit 21 Intake port 22 Exhaust port 23 Piston 24 Intake valve 25 Exhaust valve 26 Crank angle sensor 27 Fuel injection device 28 Spark plug

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F02D 45/00368 F02D 45/00 368A 368S 368Z (72) Inventor Akihiko Kadokata 2 Takara-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan F-term (reference) in Automobile Co., Ltd. PF03Z

Claims (11)

[Claims] 1. A control device for a self-ignition / spark ignition type internal combustion engine which performs an operation by self-ignition combustion in a predetermined self-ignition operation region and performs an operation by spark ignition combustion in an operation region outside the self-ignition operation region. First detection means for detecting a first determination parameter correlated with knocking intensity; second detection means for detecting a second determination parameter correlated with combustion stability; and when operating by self-ignition combustion. Determining means for determining whether the self-ignition combustion can be continued based on the two determination parameters; and determining that the self-ignition combustion cannot be continued.
Switching means for switching the combustion mode from self-ignition combustion to spark ignition combustion; and a control device for a self-ignition / spark ignition internal combustion engine. 2. A sensor for detecting in-cylinder pressure, a sensor for detecting an angular velocity of a crankshaft, a sensor for detecting vibration of a combustion chamber constituent member, and a sensor for detecting a sound of a combustion chamber constituent member. The sensor according to claim 1, further comprising at least one of a sensor for detecting a current or a voltage due to ions in the combustion gas, and detecting knocking intensity or sound vibration intensity as the first determination parameter. Of self-ignition and spark ignition type internal combustion engine. 3. The sensor according to claim 2, wherein the second detecting means detects a pressure in the cylinder, a sensor for detecting an angular velocity of a crankshaft, a sensor for detecting vibration of a combustion chamber component, and a sensor for detecting a sound of the combustion chamber component. The sensor according to claim 1, further comprising at least one of a sensor for detecting a current or a voltage due to ions in the combustion gas, and detecting combustion stability or misfire as the second determination parameter. Control device for self-ignition / spark ignition type internal combustion engine. 4. The determination means determines that continuation of self-ignition combustion is not possible when the first determination parameter exceeds an allowable range in a high-load side area of the self-ignition operation area. The self-ignition device according to claim 1, wherein when the second determination parameter exceeds an allowable range in a low-load side region of the self-ignition operation region, it is determined that continuation of self-ignition combustion is impossible. Control device for ignition / spark ignition type internal combustion engine. 5. A knocking intensity control that brings the first determination parameter closer to a target value by changing a combustion control parameter that affects both the knocking intensity and the combustion stability during an operation by self-ignition combustion. Means for determining whether the combustion control parameter has been changed by the knocking intensity control means and the second determination parameter exceeds an allowable range, so that autoignition combustion cannot be continued. The control device for a self-ignition / spark ignition type internal combustion engine according to claim 1, wherein the determination is performed. 6. A combustion stability in which the second determination parameter is brought close to a target value by changing a combustion control parameter that affects both knocking intensity and combustion stability during operation by self-ignition combustion. Control means, wherein the determination means determines that if the first control parameter exceeds an allowable range as a result of the change of the combustion control parameter by the combustion stability control means, autoignition combustion cannot be continued. The control device for a self-ignition / spark ignition type internal combustion engine according to claim 1, wherein it is determined that the internal combustion engine is present. 7. The self-ignition operation area is changed during operation by storing a result of the judgment by the judgment means for each operation condition. Of self-ignition and spark ignition type internal combustion engine. 8. The first detecting means and the second detecting means for detecting the first determining parameter and the second determining parameter for each cylinder, and the determining means and the switching means. The control device for a self-ignition / spark ignition type internal combustion engine according to any one of claims 1 to 4, wherein the control device is provided for each cylinder. 9. The first detection means and the second detection means for detecting the first judgment parameter and the second judgment parameter for each cylinder, and the judgment means and the switching means 6. The control device for a self-ignition / spark ignition type internal combustion engine according to claim 5, wherein said knocking intensity control means and said knocking intensity control means are provided for each cylinder. 10. The first determination parameter and the second determination parameter.
The first detection means and the second detection means are configured to detect the determination parameter for each cylinder, and the determination means, the switching means, and the combustion stability control means are provided for each cylinder. The control device for a self-ignition / spark ignition type internal combustion engine according to claim 6. 11. When the combustion mode of the majority of the cylinders is switched to spark ignition combustion, the switching means of the remaining cylinders switches the combustion mode to spark ignition combustion regardless of the determination of the cylinder. The control device for a self-ignition / spark ignition type internal combustion engine according to any one of claims 8 to 10.