JP3237552B2 - Combustion control device for stratified combustion internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In a conventionally used engine, fuel from a fuel injection valve is injected into an intake port, and a homogeneous mixture of fuel and air is supplied to a combustion chamber in advance. In such an engine (internal combustion 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 (therefore, fuel and air are homogeneously mixed) Is adjusted, and the engine output is controlled accordingly.

[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 technique, when the engine (internal combustion engine) is under a low load, the injected fuel is unevenly supplied around the spark plug, and the throttle valve is opened almost fully to perform stratified combustion. Thereby, the pumping loss is reduced, and the fuel efficiency is improved.

[0004]

[0005] Then, by you switch from the stratified combustion in accordance with an increase in the engine load to the homogeneous combustion side Unishi also switch to stratified combustion side from homogeneous combustion in accordance with the descent of the load of the engine in the opposite
And I Unishi.

When the intake density decreases at high altitude, the switching point from stratified combustion to homogeneous combustion shifts to the low load side, and when the intake density increases, the switching point from stratified combustion to homogeneous combustion is shifted to high load. (Japanese Patent Publication No. 5-12537). With this control, it is possible to prevent the generation of smoke due to stratified combustion in a state where the intake air density is high, and to prevent the output shortage due to the homogeneous combustion in a state where the intake air density is low.

[0007]

[Problems to be solved by the invention]

However, in the prior art, when the intake air density is reduced, the idle speed is usually kept constant.
Reduce the fuel supply to the fuel injector. However, the fuel injection valve has a guaranteed minimum injection amount.Below this minimum injection amount, the injection amount cannot be reduced , and as a result, stratified combustion does not occur in the low load side region. in the medium load region, in particular versus that stratified charge combustion is established
I can't handle it .

The present invention has been made in view of the above-described circumstances, and has as its object to reduce the intake air density when the intake air density is low .
It is an object of the present invention to provide a combustion control device for a stratified combustion internal combustion engine that can achieve stratified combustion at a medium load and improve fuel efficiency by switching to homogeneous combustion at the limit of stratified combustion due to a decrease in intake density at low load. .

[0010]

In order to achieve the above object, according to the present invention, there is provided a fuel injection means for injecting fuel into a combustion chamber of an internal combustion engine, and an ignition means for igniting the fuel in the combustion chamber. Means, intake density detecting means for detecting the intake density, and stratified combustion by controlling the fuel injection means and ignition means at low and medium loads, and controlling the fuel injection means and ignition means at high loads to achieve homogeneous combustion. In a combustion control device for a stratified combustion internal combustion engine provided with a control means for performing, the lower the intake air density according to the intake air density, the higher the limit value, and the lower the intake air density at low load , the lower the limit value at which stratified combustion cannot be performed.
To determine the discrimination injection quantity of, provided with a stratified combustion limit detecting means for the basic injection amount to increase or decrease according to increasing or decreasing the engine load detecting the limit of the stratified charge combustion by whether less than the determination injection amount, the control means The basic injection amount is determined based on the detection result of the stratified combustion limit detection unit from the determination injection amount.
The gist of the present invention is a combustion control device for a stratified combustion internal combustion engine, which switches from stratified combustion to homogeneous combustion when the combustion is smaller .

[0011]

[0012] According to the invention described in (acts) the claim 1, the control hand stage, controls the fuel injection hand Dan及 beauty ignition hand stage at low load, stratified combustion
Was carried out, at the time of high load by controlling the fuel injection hand Dan及 beauty ignition hand stages perform homogeneous combustion, the switching to the homogeneous combustion from stratified charge combustion during intake air density decreases in accordance with the intake air density detecting hand stage of the detection result low Change to load side.

[0013] The stratified combustion limit detecting means is determined as a limit value which is increased as the intake air density becomes lower in accordance with the intake air density and which cannot perform stratified combustion due to a decrease in the intake air density at low load.
When the injection amount is determined and the limit of the stratified combustion is detected based on whether or not the basic injection amount that increases or decreases according to the increase or decrease of the engine load is smaller than the discrimination injection amount , the control unit performs the control based on the detection result of the stratified combustion limit detection unit. The basic injection amount is
When the injection amount is smaller than the discrimination injection amount , switching from stratified combustion to homogeneous combustion is performed.

[0014]

[0015]

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

FIG.1Is mounted on the vehicle in this embodiment.
Schematic structure showing a combustion control device for a direct injection type engine,
FIG. The engine 1 as an internal combustion engine is, for example, 4
Combustion chamber structure of each of the cylinders 1a.
Is a figure2Is shown in As shown in these figures,
Gin 1 has a piston in cylinder block 2
The piston reciprocates in the cylinder block 2.
You. A cylinder head 4 is provided above the cylinder block 2.
Provided between the piston and the cylinder head 4
A combustion chamber 5 is formed. In the present embodiment, 1
Four valves are arranged for each cylinder 1a.
And a first intake valve 6a and a second intake valve 6b.
Valve, first intake port as 7a, second intake port as 7b
Port 8 as a pair of exhaust valves and 9 as a pair of exhaust ports.
Are shown respectively. Figure2As shown in the first
The intake port 7a includes a helical intake port,
Intake port 7b is a straight port that extends almost straight
Consist of Also, the center of the inner wall surface of the cylinder head 4
A spark plug 10 is provided in the section. In addition,
Cylinder head near first intake valve 6a and second intake valve 6b
4 A fuel injection valve 1 as a fuel injection means is provided around the inner wall surface.
1 is arranged. That is, in this embodiment,
Means that the fuel from the fuel injection valve 11 is directly supplied to the cylinder 1a.
Is to be injected.

As shown in FIG. 1 , 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 (SCV) 17 is arranged in each second intake passage 15b.
These SCVs 17 are connected to a step motor 19 via a common shaft 18. This step motor 19 is connected to an electronic control unit (hereinafter simply referred to as “ECU”).
) Is controlled based on an output signal from the control unit 30.

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

Further, in 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-mentioned 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 stratified combustion limit detection means and control means.

An accelerator sensor 26A for generating an output voltage proportional to the amount of depression of the accelerator pedal 24 is connected to 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.

Further, in the present embodiment, the atmospheric pressure P
Atmospheric pressure sensor 63 as atmospheric pressure detecting means for detecting A
The output of the atmospheric pressure sensor 63 is input to the input port 35 via the A / D converter 37.

[0027] In this embodiment, these throttle sensor 25, an accelerator sensor 26 A, fully closed switch 26
B, the top dead center sensor 27, the crank angle sensor 28, the swirl control valve sensor 29, and the like constitute an operating state detecting means.

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

Next, a program related to control according to the present embodiment in the engine combustion control device having the above configuration will be described with reference to a flowchart. That is, FIG. 3 is a flowchart showing the “required combustion mode determination routine when the intake air density is low” in the present embodiment, which is executed, for example, by interruption every predetermined crank angle.

When the processing shifts to this routine, the ECU
First, at step 101, it is determined whether or not the highland switching flag XQHACi-1 in the previous control routine is "0". This high altitude switching flag XQH
If ACi-1 is "0", the process proceeds to a step 102, and if "1", the process proceeds to a step 105.

In step 102, it is determined whether or not the basic fuel injection amount QALLINJB is smaller than a highland switching determination injection amount (hereinafter referred to as a determination injection amount) QHAC.
Here, the basic fuel injection amount is calculated in a separate injection amount calculation routine. Based on various signals such as the engine speed NE and the accelerator opening ACCP at the time of this control, the basic injection amount QALLINJB is calculated. It has been calculated.

Also, the discrimination injection amount QHAC is determined in step 1
It is calculated from tMQHAC map of FIG. 5 in 02. In the figure, the tMQHAC map indicates the atmospheric pressure tP.
The higher the A (KPa), the smaller the determined injection amount QHAC, and the lower the atmospheric pressure tPA (KPa), the larger the determined injection amount QHAC (mm ³ / st). Here, mm ³ / st represents the injection amount in one stroke of the cylinder. This discrimination injection amount QHAC
Is determined by an experiment or the like such that when the atmospheric pressure is reduced and the intake air density is reduced, stratified charge combustion becomes a limit value. Then, in step 102,
The atmospheric pressure PA detected and input by the atmospheric pressure sensor 63 is represented by tP
A represents the discrimination injection amount QHA corresponding to the atmospheric pressure tPA.
After C is determined, determination is performed.

If it is determined in step 102 that the basic fuel injection amount QALLINJB is smaller than the discrimination injection amount QHAC, the process proceeds to step 103, and the process proceeds to step 103.
, The high altitude switching flag XQHAC is set to “1”. In the next step 104, the combustion mode (operation mode) FMODE is set to "3", and this routine is ended once. Step 102 corresponds to the stratified combustion limit detection means of the present invention.

In this embodiment, under the control of the ECU 30, the engine 1 can take each of the combustion states of stratified combustion, weakly stratified combustion, homogeneous lean combustion, and homogeneous combustion. Then, in a required combustion mode setting routine separate from the “required combustion mode determination routine when the intake air density decreases”, the engine speed NE and the accelerator opening AC
When the combustion state required based on the CP is stratified combustion, the combustion mode FMODE is set to “0”. When the combustion state is weakly stratified combustion, the combustion mode FMODE is set to “1”.
, The combustion mode FMODE is set to “2” in the case of homogeneous lean combustion, and the combustion mode FMODE is set to “3” in the case of homogeneous combustion.

If it is determined in step 102 that the basic fuel injection amount QALLINJB is equal to or greater than the discrimination injection amount QHAC, the process proceeds to step 105. Step 101,
Alternatively, when the routine proceeds from step 102 to step 105, the basic fuel injection amount QALLINJB becomes equal to the determination injection amount QH.
It is determined whether or not the value exceeds a value obtained by adding a predetermined value β to AC. When the process proceeds from step 101 to step 105, that is, the highland switching flag XQ
When HACl-1 is "1", the atmospheric pressure tPA of the tMQHAC map is a predetermined value α (>
0) is defined as tPA, and the value obtained by subtracting
The determination injection amount QHAC corresponding to the PA is determined from the map tMQHAC.

Also, from step 102 to step 105
, That is, when XQHACi-1 is "0", the atmospheric pressure tPA of the tMQHAC map
Is based on the current atmospheric pressure PA as tPA, and determines the determined injection amount corresponding to this tPA from the map tMQHAC based on the determined injection amount Q
Ask for HAC. The predetermined value β (> 0) is the basic value when the high altitude switching flag XQHACi-1 is “0”.
The fuel injection amount QALLINJB is for setting a predetermined range of QHAC ≦ QALLINJB ≦ QHAC + β, that is, for setting the determination sensitivity. The fuel injection amount QALLINJB is determined in advance by experiments or the like and stored in the ROM 33. Accordingly, the determination sensitivity decreases as the predetermined value β increases, and the determination sensitivity increases as the determination value β decreases.

In step 105, if the basic fuel injection amount QALLINJB is equal to or less than a value obtained by adding a predetermined value β to the discrimination injection amount QHAC, this routine is temporarily ended.

In step 105, the basic fuel injection amount QALLINJB is added to the discrimination injection amount QHAC by a predetermined value β.
If it exceeds the value obtained by adding, the process proceeds to step 106. In step 106, it is determined whether or not the current engine speed NE satisfies K1 ≦ NE ≦ K2. In this embodiment, K1 and K2 are a rotation speed (rpm) in a medium speed range and a rotation speed (rpm) in a high speed range, respectively. The reason why the step of determining whether or not the engine speed NE is within these predetermined ranges is provided is that the operation mode (combustion mode) is temporarily changed from homogeneous combustion to stratified combustion when the engine speed NE is outside this predetermined range. Is switched, torque torque occurs. Therefore, in the combustion mode determination routine when the intake air density is low, the torque shock is alleviated by enabling the switching from the homogeneous combustion to the stratified combustion only within this predetermined range, and the combustion mode is switched stepwise within this range. It is.

In step 106, if the engine speed NE is not K1≤NE≤K2, this processing routine is temporarily terminated. Also, if the engine speed NE is K1 ≦
If NE ≦ K2, the process proceeds to step 107, where the highland switching flag XQHAC is reset to “0”. Then, in the next step 108, the combustion mode FMOD
E is set to "0", and this processing routine is temporarily ended.

After terminating this control routine, the ECU 30 operates the fuel injection valve 11 in order to cause stratified charge combustion or homogeneous combustion in the required combustion (operation) mode set in this control routine. In addition to performing fuel control and ignition control of the ignition plug 10, the step motor 1
The control of the intake system such as 9, 22 is performed.

In the control of the fuel injection valve 11, the ignition plug 10, and the intake system, in this embodiment, the combustion mode FMODE is changed from "0" to "0" by the determination of the "required combustion mode determination routine when the intake density is low". 3 ", that is, when shifting from the stratified combustion mode to the homogeneous combustion mode, the shift is controlled without passing through the intermediate combustion mode (homogeneous lean combustion, weak stratified combustion).

The determination of the "requested combustion mode determination routine when the intake air density decreases" determines the combustion mode FMO.
When DE is changed from “3” to “0”, that is,
When transitioning from the homogeneous combustion mode to the stratified combustion mode, an intermediate combustion mode (homogeneous lean combustion, weak stratified combustion)
Through the control. By doing so, torque shock is prevented from occurring.

The steps 105 and 10
If it is determined to be “NO” in step 6, the fuel control of the fuel injection valve 11 and the ignition plug 1 are performed in accordance with the combustion mode set in the separate required combustion mode setting routine.
0 ignition control and the step motors 19 and 2
Control of the intake system such as 2 is performed.

[0044] For the additional requirements combustion mode setting routine is well known, here, although not described in detail, FIG. 4
The switching of the combustion mode will be briefly described with reference to FIG. That is, when the intake air density is the vehicle in low-lying not decreased, and the stratified combustion, when switching between the homogeneous combustion, where the parameters of the basic fuel injection amount QALLINJB and the engine rotational speed NE shown in FIG. 4 The required combustion mode is determined depending on whether there is any, and the switching control of the required combustion mode is performed according to the determined required combustion mode.

In the figure, the vertical axis represents the basic fuel injection amount QA.
LLINJB, the horizontal axis is the engine speed NE. Therefore, for example, the engine is currently in the stratified combustion region and the engine speed N
When E is NE1, the basic fuel injection amount QALLIN
When JB increases according to the engine load, the switching line X
Each time the basic fuel injection amount QALLINJB exceeds 3, X2, X1, the required combustion mode switches to weak stratified charge combustion, homogeneous lean combustion, and homogeneous combustion. Conversely, when the requested combustion mode is currently in the homogeneous combustion region and the basic fuel injection amount QALLINJB decreases according to the engine load, the switching lines X1, X2, X3 are changed to the basic fuel injection amount QAL.
Each time LINJB is exceeded, the required combustion mode switches to homogeneous lean combustion, weak stratified combustion, and stratified combustion.

When the engine speed NE is equal to a certain speed N
In case of exceeding E2, 2 of homogeneous lean and homogeneous combustion
There are only two required combustion zones, and the engine speed N
When E exceeds the high-speed side rotational speed NE3, the combustion is controlled in the combustion mode of only the homogeneous combustion regardless of the basic fuel injection amount QALLINJB.

The operation and effect of the embodiment configured as described above will now be described. (B) in the flowchart of FIG. 3, Step 10
1 is “YES”, and in step 102, “YES”
In step 102, the lower the atmospheric pressure tPA becomes, the more the discrimination injection amount QHAC becomes the atmospheric pressure tP
A is made variable according to A, and the discrimination injection amount QHAC increases. Then, in the subsequent step 104, the combustion mode FMODE is set to “3”.
Under the control of the ECU 30, control of homogeneous combustion is performed.

As a result, in a low load region in which stratified charge combustion is not established due to a decrease in the intake air density, the atmospheric pressure t
The lower the PA, the easier it is to set the combustion mode FMODE to "3", so that homogeneous combustion can be performed.

In step 101 to step 104, since the high altitude switching flag XQHACi-1 has been reset to "0" in the previous control cycle determination routine, In, stratified combustion is being performed.

[0050] Thus, lowered atmospheric pressure, when lowered intake air density, the switching line of the stratified combustion region in FIG. 4 Y1
From the state where the control of the stratified combustion has been performed until now, the control can be promptly shifted to the control of the homogeneous combustion.

[0051] In (b) the flowchart of FIG. 3,
Step 101 is "YES" and step 102 is "N
In step 105, it is determined as "YES" when the basic fuel injection amount QALLINJB is as follows.

QHAC + β <QALLINJB In this case, if the engine speed NE at that time is in the range between K1 and K2 in step 106, it is determined that stratified combustion is possible in the medium load range, and in step 108, The combustion mode FMODE was set to "0".

As a result, stratified charge combustion can be performed in a medium load range, and fuel efficiency can be improved.
Emission can be reduced. (C) In the flowchart of FIG. 3 , “NO” is determined in step 101, and step 105
In the case of shifting to the high altitude switching flag XQHACi-1
Is set to “1”. Therefore, step 105
When the injection quantity QHAC is determined by the tMQHAC map shown in FIG. 5 , the atmospheric pressure tPA is a value obtained by subtracting a predetermined value α from the current atmospheric pressure PA (= PA−α), and the determination corresponding to the tPA is performed. A determination injection amount QHAC was obtained from the injection amount map tMQHAC.

Therefore, if "YES" is determined in steps 105 and 106, and in step 108, the combustion mode FMODE is set to "0",
The ECU 30 controls stratified combustion.

As a result, when switching from stratified combustion to homogeneous combustion, the control from stratified combustion to homogeneous combustion is performed by the switching line Y1 in FIG. 4 , whereas when switching from homogeneous combustion to stratified combustion is performed. , it can be performed by switching the stratified charge combustion from homogeneous combustion at switching line Y2 in FIG.

The embodiments are not limited to the above embodiments, and may be configured as follows, for example. (A) In the above embodiment, the present invention is embodied in the in-cylinder injection type engine 1. However, the invention may be embodied in a type that performs so-called general stratified combustion or weakly stratified combustion. . For example, the intake valves 6 of the intake ports 7a and 7b
a and 6b include those of the type that sprays toward the back side of the umbrella portion. 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.

[0057]

[0058]

As described in detail above, according to the present invention,
By switching to homogeneous combustion at the limit of stratified combustion, due to reduced intake density at low load when intake air density is low ,
An excellent effect is achieved in that stratified combustion can be achieved at a medium load and fuel efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a combustion control of an engine according to an embodiment of the present invention.
The schematic block diagram which shows a control apparatus.

FIG. 2 is an enlarged sectional view showing a cylinder portion of the engine.

FIG. 3 is a diagram showing a “combustion mode determination routine” executed by the ECU .
Flowchart showing "Chin".

FIG. 4 shows a switching area for switching a combustion mode .
FIG.

FIG. 5 is an explanatory diagram showing a fuel injection amount map.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Stratified combustion internal combustion engine, 11 ... Fuel injection valve, 17 ... Swirl control valve, 19 ... Step motor, 28 ... Crank angle sensor, 29 ... Swirl control valve sensor, 30 ... Stratified combustion limit detection means and control means An atmospheric pressure sensor as atmospheric pressure detecting means.

Claims (1)

(57) [Claims] A fuel injection means for injecting fuel into a combustion chamber of an internal combustion engine; an ignition means for igniting the combustion chamber; an intake density detection means for detecting an intake density; In a combustion control device for a stratified-combustion internal combustion engine having a control means for controlling the ignition means to perform stratified combustion and controlling the fuel injection means and the ignition means to perform homogeneous combustion at a high load, the intake density is determined according to the intake density. Is determined, the discrimination injection amount is determined as a limit value at which the stratified combustion cannot be performed due to a decrease in the intake air density at a low load, and the stratification is determined based on whether the basic injection amount that increases or decreases according to the increase or decrease of the engine load is smaller than the discrimination injection amount. comprising a stratified combustion limit detecting means for detecting the limit of combustion, the control means, based on a detection result of the stratified combustion limit detecting means, the basic injection amount is the Small than another injection quantity
A combustion control device for a stratified combustion internal combustion engine, which switches from stratified combustion to homogeneous combustion at a time .