JPH10169490A - Idling speed controller for stratified combustion internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent combustion from being unstable during idling in an idling speed controller for an internal combustion engine capable of performing stratified combustion. SOLUTION: A fuel injection valve 11 is disposed in the inner wall circumference of a cylinder head 4 located in the vicinity of the first and second intake valves 6a and 6b of an engine 1, and fuel from the fuel injection valve 11 is directly injected into a cylinder 1a. A throttle valve 23 opened/closed by a step motor 22 is provided in an intake duct 20. An electronic controller (ECU) 30 controls an idle rotational number by performing, during idling of the engine 1, not only an idling speed for both stratified combustion and uniform combustion, i.e., a fuel injection amount, but also a intake air amount. Thus, a combustion state is made stable. Also, the ECU 30 uses, for its control, the concept of a control amount according to a combustion state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle speed control device for an internal combustion engine capable of performing stratified charge combustion.

[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.

As a technique capable of performing stratified combustion as described above, for example, a technique disclosed in Japanese Patent Application Laid-Open No. 4-370343 is known. In this technology, either a stratified combustion or a homogeneous combustion combustion method is adopted depending on operating conditions,
At least at low and medium loads, stratified fuel injection and ignition are controlled, and at high loads, homogeneous combustion fuel injection and ignition are controlled. When the engine is idling, only the fuel injection amount is controlled to increase or decrease according to the coolant temperature. With such a technique, stratified combustion at low load is favorably maintained, and warm-up during cold is promoted.

[0005]

However, in the technology described in the above-mentioned conventional publication, the following problems may occur. That is, at the time of idling, when stratified combustion is performed, the combustion state of the engine may be deteriorated. In such a case, if the control of the idle speed by the stratified combustion, that is, the control of increasing or decreasing the fuel injection amount, is performed, there is a possibility that the combustion may become unstable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an idling speed control apparatus for an internal combustion engine capable of performing stratified combustion, in which combustion during idling becomes unstable. It is an object of the present invention to provide an apparatus for controlling the idling speed of a stratified combustion internal combustion engine, which can prevent the occurrence of stagnation.

[0007]

In order to achieve the above object, according to the present invention, as shown in FIG. 1, an internal combustion engine M1 capable of performing stratified combustion and homogeneous combustion is provided.
An operating state detecting means M2 for detecting an operating state of the internal combustion engine M1, and a control amount is calculated based on a detection result of the operating state detecting means M2, and the rotation of the internal combustion engine M1 during idling is calculated based on the control amount. A stratified-combustion internal combustion engine idle speed control device provided with a control means M3 for controlling the number of combustions, wherein the combustion state of the internal combustion engine M1 is determined to be stratified combustion based on the detection result of the operating state detection means M2. Combustion state determining means M for determining whether to perform combustion or homogeneous combustion
4, when the combustion state determined by the combustion state determination means M4 is a homogeneous combustion state, the control amount in the homogeneous combustion state is calculated, and the internal combustion engine M is calculated based on the control amount.
The gist of the invention is to provide a homogeneous idle control means M5 for controlling the number of revolutions at the time of idling.

Further, in the invention according to claim 2,
An internal combustion engine capable of performing stratified combustion and homogeneous combustion, an operating state detecting means for detecting an operating state of the internal combustion engine, and a control amount is calculated based on a detection result of the operating state detecting means.
Control means for controlling the number of revolutions of the internal combustion engine during idling based on the control amount. A combustion state determining means for determining whether the combustion state of the internal combustion engine is stratified combustion or homogeneous combustion; and a stratified combustion state when the combustion state determined by the combustion state determination means is a stratified combustion state. And the stratified idle control means for controlling the idling speed of the internal combustion engine based on the control amount, and the combustion state determined by the combustion state determination means is a homogeneous combustion state. And a homogeneous idle control means for calculating the control amount in the homogeneous combustion state and controlling the number of revolutions of the internal combustion engine during idling based on the control amount. Are you as its gist.

Further, according to a third aspect of the present invention, in the idle speed control apparatus for a stratified combustion internal combustion engine according to the first or second aspect, the control amount by the homogeneous idle control means is controlled by the intake of the internal combustion engine. The gist is the amount of air.

According to a fourth aspect of the present invention, in the idle speed control apparatus for a stratified combustion internal combustion engine according to the second aspect, the control amount by the stratified idle control means is supplied to the internal combustion engine. The gist is that the fuel amount is

In addition, according to a fifth aspect of the present invention, in the idle speed control apparatus for a stratified combustion internal combustion engine according to any one of the first to fourth aspects, the control amount should be reflected at the next control. The gist is that it is a learning value.

According to a sixth aspect of the present invention, in the idle speed control apparatus for a stratified combustion internal combustion engine according to any one of the first to fifth aspects, the control amount is related to whether or not the engine is in a homogeneous combustion state. The main point is that the parameters are shared as dimensionless parameters.

According to a seventh aspect of the present invention, in the idle speed control apparatus for a stratified combustion internal combustion engine according to the third aspect, the means for adjusting the intake air amount includes:
An electronically controlled throttle mechanism including a throttle valve provided in an intake passage of the internal combustion engine and an actuator for opening and closing the throttle valve; and an idle provided in a bypass intake passage bypassing a throttle valve provided in the intake passage. The gist of the invention is that it is constituted by at least one of an ISC mechanism including a speed control valve and an actuator for opening and closing the valve.

(Operation) According to the first aspect of the present invention, as shown in FIG. 1, the operating state of the internal combustion engine M1 capable of performing stratified combustion and homogeneous combustion is detected by the operating state detecting means M2. The control means M3 calculates a control amount based on the detection result, and controls the number of revolutions of the internal combustion engine M1 during idling based on the control amount.

In the present invention, the operating state detecting means M2
Based on the detection result, whether the combustion state of the internal combustion engine M1 is stratified combustion or homogeneous combustion is determined by the combustion state determination means M4.
Is determined by When the determined combustion state is the homogeneous combustion state, the homogeneous idle control means M5
The control amount in the homogeneous combustion state is calculated, and the number of revolutions of the internal combustion engine M1 during idling is controlled based on the control amount.

Therefore, when the combustion state of the internal combustion engine M1 is poor, the idle speed control in the homogeneous combustion state is performed. Therefore, the combustion state can be stabilized.

Also, in the invention of the second aspect, basically, the same operation as the invention of the first aspect is exerted. That is, when the combustion state determined by the combustion state determination means is a stratified combustion state, the control amount in the stratified combustion state is calculated by the stratified idle control means, and the control amount during idling of the internal combustion engine is calculated based on the control amount. The rotation speed is controlled. On the other hand, when the combustion state determined by the combustion state determination means is a homogeneous combustion state, a control amount in the homogeneous combustion state is calculated by the homogeneous idle control means, and based on the control amount, the idling of the internal combustion engine during idling is performed. The rotation speed is controlled.

Further, according to the third aspect of the present invention,
In addition to the effects of the invention described in claims 1 and 2, the control amount by the homogeneous idle control means is an intake air amount of the internal combustion engine. Therefore, as in a general internal combustion engine (an internal combustion engine that performs only homogeneous combustion), the idle speed is controlled by controlling the intake air amount, and the combustion state is further stabilized.

In addition, according to the invention described in claim 4,
In addition to the effect of the invention described in claim 2, the control amount by the stratified idle control means is a fuel amount supplied to the internal combustion engine. Therefore, the idling speed can be controlled while maintaining the stratified combustion, and the fuel efficiency can be improved.

In addition, according to the invention described in claim 5,
In addition to the effects of the invention described in claims 1 to 4, the control amount is a learning value to be reflected at the next control. Therefore, when the next idle speed control is performed, an appropriate and stable idle speed can be secured regardless of the combustion state.

According to the sixth aspect of the present invention, in addition to the functions of the first to fifth aspects, the control amount is a dimensionless parameter irrespective of whether the combustion state is homogeneous. It is shared. Therefore, it is possible to control different control targets with one logic, thereby simplifying the control.

Further, according to the invention described in claim 7,
In addition to the function of the invention described in claim 3, the means for adjusting the intake air amount is an electronic device comprising a throttle valve provided in an intake passage of the internal combustion engine and an actuator for opening and closing the throttle valve. And a controllable throttle mechanism, and at least one of an ISC mechanism including an idle speed control valve provided in a bypass intake passage for bypassing a throttle valve provided in the intake passage and an actuator for opening and closing the valve. I have. Therefore, there is no need to provide a separate actuator for controlling the idle speed.

[0023]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an idling speed control apparatus for a stratified combustion internal combustion engine according to the present invention.

FIG. 2 is a schematic configuration diagram showing an idle speed control device of a direct injection engine mounted on a vehicle in the present embodiment. Engine 1 as internal combustion engine
Has, for example, four cylinders 1a, and each of these cylinders 1a
3 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 on an upper portion of the cylinder block 2.
A combustion chamber 5 is formed between the two. 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. Two intake ports, 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. This spark plug 10 includes:
The igniter 12 via a distributor (not shown)
Is applied. And
The ignition timing of the ignition plug 10 is determined by the igniter 1
2 is determined by the output timing of the high voltage. Further, a fuel injection valve 11 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, so that not only homogeneous combustion but also so-called stratified combustion is performed. I have.

As shown in FIG. 2, a first intake port 7a and a 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 17 is arranged in each second intake passage 15b. These swirl control valves 17 are connected via a common shaft 18 to a step motor 19 as an actuator. The step motor 19 is controlled based on an output signal from an electronic control unit (hereinafter simply referred to as “ECU”) 30 described later.

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 this 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 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 control means, combustion state determination means, homogeneous idle control means, and stratified idle control means.

The accelerator pedal 24 is connected to an accelerator sensor 26A for generating 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 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.

In this embodiment, the throttle sensor 25, the accelerator sensor 26A,
B, a top dead center sensor 27, a crank angle sensor 28, a swirl control valve sensor 29, an intake pressure sensor 61, a water temperature sensor 62, and the like constitute an operating state detecting means.

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, based on signals from the sensors 25 to 29, 61, and 62, the ECU 30 operates according to a control program stored in the ROM 33,
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 related to various controls according to the present embodiment in the idling speed control apparatus for a stratified combustion engine having the above-described configuration will be described with reference to flowcharts. That is, FIG. 4 shows the learning values (the homogeneous combustion learning value DJDG and the stratified combustion learning value TJD) when performing the idle speed control in the present embodiment.
9 is a flowchart showing a “learning value calculation routine” for calculating G), which is executed by the ECU 30 at, for example, an interruption every predetermined crank angle. The learning value calculated in this routine (the learning value for homogeneous combustion DJDG)
And the stratified combustion learning value TJDG) are controlled by a final control amount DCA at the time of idling in a later-described routine.
This is reflected in the calculation of L. Further, in a separate routine, the ECU 30 executes the above-mentioned sensors 25 to 29, 61,
Based on the signal from 62, it is determined whether to execute stratified combustion or homogeneous combustion, and the combustion state is controlled according to the determination result. For example, when the cooling water temperature THW is lower than a predetermined temperature at the time of starting or the like, since the atomization of the fuel is not so good, the homogeneous combustion is executed. In addition, low
In the case of medium rotation speed and low / medium load, stratified combustion is executed. Further, when the engine speed is high and the load is high, homogeneous combustion is performed.

When the processing shifts to this routine, the ECU
30 first determines in step 101 whether the learning condition is satisfied. Here, the learning conditions include that the engine is currently idling, that the engine speed NE does not fluctuate significantly, and that there is no other disturbance. When the learning condition is not satisfied, the subsequent processing is temporarily terminated. On the other hand, if the learning condition is satisfied, step 102
Move to.

In step 102, the current learning value tDG is calculated. Here, the current learning value tDG is a dimensionless parameter, like the control amount DCAL, and is, for example, a ratio to a predetermined reference amount (for example, a fuel injection amount at no load or a throttle opening). This is the value represented by That is, when the operation in the stratified combustion is currently being performed, the control of the idle speed is performed by directly controlling the fuel injection amount, so that the target fuel injection during the feedback control at that time is performed. The current learning value tDG is calculated based on the amount (unit: [mm ³ / st]). On the other hand, when the operation in the homogeneous combustion is currently performed, the control of the idle speed is performed by controlling the intake air amount by controlling the opening and closing of the throttle valve 23. Based on the target throttle opening (unit is [°]) during control,
The current learning value tDG is calculated.

Next, at step 103, it is determined whether or not the engine is currently operating in homogeneous combustion. Then, when the operation in the homogeneous combustion is performed, the process proceeds to step 104. In step 104, the current learning value tDG calculated this time is used as the homogeneous combustion learning value DJ.
DG is set, and the subsequent processing ends once.

If the engine is not currently operating in homogeneous combustion, in step 105, the current learning value tDG calculated this time is set as the stratified combustion learning value TJDG, and the subsequent processing is temporarily terminated. .

As described above, the "learning value calculation routine"
In, the current learning value tDG is set as the homogeneous combustion learning value DJDG or the stratified combustion learning value TJDG, respectively, according to the combustion state.

Next, how the learning values calculated and set as described above (the homogeneous combustion learning value DJDG and the stratified combustion learning value TJDG) are reflected will be described. That is, FIG. 5 shows a learning value (the homogeneous combustion learning value D) when performing the idle speed control in the present embodiment.
FIG. 9 is a flowchart illustrating a “learning value reflection processing routine” that calculates a final control amount DCAL during idling using JDG and the stratified combustion learning value TJDG), and thereby performs idle speed control. For example, it is executed by interruption every predetermined crank angle.

When the processing shifts to this routine, the ECU
30 first determines in step 201 whether or not the current time is the starting time. Here, at the time of starting, in order to ensure good combustion and good engine startability, operation with homogeneous combustion is performed. Therefore, if the current time is the start time, the process proceeds to step 204 described later. On the other hand, if the current time is not the start time, the process proceeds to step 202.

In step 202, it is determined whether stratified combustion is currently required. If stratified combustion is required, the process proceeds to step 203. In step 203, the currently set stratified charge combustion learning value TJDG is set as the learning value DG.
Then, the process proceeds to step 205.

In step 202,
If stratified combustion is not required, it is determined that homogeneous combustion is required, and the process proceeds to step 204 as in the case where an affirmative determination is made in step 201. Step 2
In step 04, the currently set homogeneous combustion learning value DJDG is set as the learning value DG. Then, the process proceeds to step 205.

After shifting from step 203 or step 204, in step 205, the control amount DCAL is calculated and set based on the learning value DG set this time. That is, with respect to the learning value DG set this time, separately calculated correction terms (water temperature correction term DTHW, start time correction term DSTA, torque converter correction term DE, air conditioner correction term DA)
C, the power steering correction term DPS, etc.) is set as a new control amount DCAL. Note that these correction terms are determined values regardless of whether stratified combustion is performed or homogeneous combustion is performed. Then, the ECU 30 once ends the subsequent processing.

As described above, in the "learning value reflection processing routine", the learning value for homogeneous combustion DJDG or the learning value for stratified combustion TJDG is set as the learning value DG in accordance with the combustion state at that time. The control amount DCAL during idling is set. Further, the control amount DCAL set in this manner is reflected in the idle speed control in the following manner according to each combustion state. In other words, if operation in stratified combustion is currently being performed,
As described above, the control of the idle speed is performed by controlling the fuel injection amount. Therefore, the fuel injection amount QFisc at that time is set by the following equation (1).

QFisc = DCAL × Kf−α (1) where Kf is a unit conversion coefficient [mm ³ / st /%], and α is an offset amount. In addition, when the operation in the homogeneous combustion is currently performed, the idle speed control is performed by controlling the opening and closing of the throttle valve 23 to control the intake air amount as described above. Therefore, the throttle opening QAisc at that time is set by the following equation (2).

QAisc = DCAL × Ka−β (2) where Ka is a unit conversion coefficient [° /%] and β is an offset amount. Next, the operation and effect of the present embodiment will be described.

(A) In the present embodiment, in the idling speed control of the engine 1 performing the stratified combustion, the engine 1
Depending on the operating state of the engine, the idle speed control in stratified combustion, that is, the idle speed control in the homogeneous combustion, that is, the opening of the throttle valve 23, The intake air amount is controlled by controlling the degree. Therefore, the combustion state can be stabilized.

(B) In this embodiment, when the stratified combustion state is set, the idling speed control in the stratified combustion is performed. For this reason, by controlling the fuel injection amount supplied to the engine 1, the idling speed can be controlled while maintaining the stratified combustion, and the fuel efficiency can be improved.

(C) Further, in this embodiment, the control amount DCA
The concept of L was used. This control amount DCAL
Is shared as a dimensionless parameter regardless of whether it is in a homogeneous combustion state or not. Therefore, it is possible to control different control targets such as the fuel injection valve 11 and the step motor 22 with one logic, and the control can be significantly simplified.

(D) In addition, simply, the control amount D during stratified combustion
When CAL is used as it is during homogeneous combustion, or when control amount DCAL during homogeneous combustion is used as it is during stratified combustion, the control target is different, and the fuel injection amount or intake air amount is different from the required amount. In some cases. In such a case, overshoot or undershoot of the engine speed may be a concern. In the present embodiment, however, when calculating the control amount DCAL, that is, when using the learning value DG, the learning value D for homogeneous combustion is used.
JDG or the learning value for stratified combustion TJDG is selectively used depending on the combustion state at that time.

For this reason, as shown in FIG. 6, when the characteristics of the fuel injection valve 11 and the step motor 22 do not correspond to each other due to the functional difference between the individual fuel injection valve 11 and the step motor 22. However, by using the learning value DJDG for homogeneous combustion or the learning value TJDG for stratified combustion, it is possible to secure the expected fuel injection amount or intake air amount. As a result, deterioration of controllability can be suppressed.

(E) In addition, in the present embodiment, when calculating the control amount DCAL, the learning value DG to be reflected at the next control is adopted. For this reason, when the next idle speed control is performed, an appropriate and stable idle speed can be ensured regardless of the combustion state.

(F) Further, in this embodiment, the throttle valve 2 is used as a means for adjusting the intake air amount.
3 and an electronically controlled throttle mechanism including a step motor 22. Therefore, it is not necessary to provide a separate actuator for controlling the idle speed, so that an increase in cost can be suppressed.

The embodiment is not limited to the above, but may be modified as follows. (1) In the above embodiment, the intake air amount is adjusted by employing the electronically controlled throttle mechanism including the throttle valve 23 and the step motor 22. On the other hand, the intake air amount may be adjusted by an ISC mechanism including an idle speed control valve provided in a bypass intake passage that bypasses a throttle valve 23 provided in the intake passage and an actuator for opening and closing the valve. Good.

(2) 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.

(3) In the above embodiment, the present invention is embodied in the case of the gasoline engine 1 as the internal combustion engine. However, the present invention can be embodied in the case of a diesel engine or the like.

(4) The content of the control may be such that the correction term in the above embodiment is not considered.

[0062]

As described in detail above, according to the present invention,
In an idle speed control device for an internal combustion engine capable of performing stratified combustion, an excellent effect is obtained in that combustion during idling can be prevented from becoming unstable.

[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 showing an idle speed control device for a stratified combustion engine according to one embodiment.

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

FIG. 4 is a flowchart illustrating a “learning value calculation routine” executed by the ECU.

FIG. 5 is a flowchart showing a “learning value reflection processing routine” executed by the ECU.

FIG. 6 is a timing chart showing an example of a behavior of a control amount in different combustion states.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine as internal combustion engine, 11 ... Fuel injection valve, 2
2 Step motor, 23 Throttle valve, 25 Throttle sensor forming operating state detecting means, 26A Accelerator sensor forming operating state detecting means, 26B Fully-closed switch forming operating state detecting means, 27 Operating Top dead center sensor constituting state detection means, 28 ... Crank angle sensor constituting operation state detection means, 29 ... Swirl control valve sensor constituting operation state detection means,
30 ... ECU constituting control means, combustion state determination means, homogeneous idle control means, stratified idle control means, 61 ...
Intake pressure sensor constituting the operating state detecting means, 62... Water temperature sensor constituting the operating state detecting means.

Claims (7)

[Claims] An internal combustion engine capable of performing stratified combustion and homogeneous combustion; an operating state detecting means for detecting an operating state of the internal combustion engine; and a control amount calculated based on a detection result of the operating state detecting means. Control means for controlling the number of revolutions of the internal combustion engine during idling based on the control amount, the idle speed control apparatus for a stratified combustion internal combustion engine, based on a detection result of the operating state detection means, Combustion state determining means for determining whether the combustion state of the internal combustion engine is stratified combustion or homogeneous combustion; and when the combustion state determined by the combustion state determination means is a homogeneous combustion state, A stratified-combustion internal combustion engine, comprising: a homogeneous idle control means for calculating the control amount and controlling the idling speed of the internal combustion engine based on the control amount. Idle speed control device. 2. An internal combustion engine capable of performing stratified combustion and homogeneous combustion; operating state detecting means for detecting an operating state of the internal combustion engine; and calculating a control amount based on a detection result of the operating state detecting means. Control means for controlling the number of revolutions of the internal combustion engine during idling based on the control amount, the idle speed control apparatus for a stratified combustion internal combustion engine, based on a detection result of the operating state detection means, Combustion state determining means for determining whether the combustion state of the internal combustion engine is stratified combustion or homogeneous combustion; and if the combustion state determined by the combustion state determination means is a stratified combustion state, the stratified combustion state A stratified idle control means for controlling the idling speed of the internal combustion engine based on the control amount, and a fuel level determined by the combustion state determination means. When the state is the homogeneous combustion state, the control amount in the homogeneous combustion state is calculated, and the homogeneous idle control means for controlling the number of revolutions of the internal combustion engine during idling based on the control amount is provided. An idle speed control device for a stratified combustion internal combustion engine. 3. The idling speed control device for a stratified combustion internal combustion engine according to claim 1, wherein the control amount by the homogeneous idle control means is an intake air amount of the internal combustion engine. 4. The apparatus according to claim 2, wherein the control amount by the stratified idle control means is a fuel amount supplied to the internal combustion engine. 5. The idle speed control device for a stratified combustion internal combustion engine according to claim 1, wherein the control amount is a learning value to be reflected at the next control. 6. The stratified combustion internal combustion engine according to claim 1, wherein the control amount is shared as a dimensionless parameter regardless of whether the combustion state is homogeneous. Engine idle speed control device. 7. An electronically controlled throttle mechanism comprising a throttle valve provided in an intake passage of the internal combustion engine, an actuator for opening and closing the throttle valve, and an intake passage. IS comprising an idle speed control valve provided in a bypass intake passage for bypassing a throttle valve provided in the engine and an actuator for opening and closing the valve.
The idle speed control device for a stratified combustion internal combustion engine according to claim 3, wherein the device is configured by at least one of a C mechanism.