JPH1136920A - Fuel supply control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly change over the combustion condition from stratified combustion into homogeneous combustion during deceleration. SOLUTION: It is determined that deceleration is started when the degree of acceleration becomes lower than a predetermined value, a new map for computing a desired basic equivalence ratio is selected after a predetermined time DLTFM elapses, and the desired basic equivalence ratio TFBYA00 is computed with the use of thus selected map. Thereafter, a phase delay is compensated for the desired basic equivalence ratio TFBYA00 so as to set a compensated desired basic equivalence ratio TFBYA4 which is then compared with a predetermined equivalence ratio TFVYADF, and the smaller one of them is set as a desired equivalence ratio TFVYA0. Further, a combustion flag FSTRR1 is changed over so as to carry out homogeneous combustion when the desired equivalence ratio TFVYA0 becomes larger than a threshold value TFACH of equivalence ratio with which the combustion is changed over into homogeneous combustion from stratified combustion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply control device for an internal combustion engine, and more particularly to a technique for smoothly switching a combustion state from stratified combustion to homogeneous combustion during deceleration.

[0002]

2. Description of the Related Art Conventionally, fuel supply is stopped during deceleration,
2. Description of the Related Art A fuel supply control device for performing fuel cut control for suppressing HC and improving fuel efficiency is known (JP-A-54-1489).
No. 29).

[0003]

Since such a fuel supply control device is premised on homogeneous combustion in which a combustible air-fuel mixture is burned in the vicinity of a stoichiometric air-fuel ratio, there is almost no change in the target equivalence ratio during deceleration, and the fuel The torque fluctuations during later recovery did not matter much. However, in a direct injection type internal combustion engine, which has been developed in recent years for the purpose of improving exhaust properties and fuel efficiency and injecting fuel directly into a cylinder to perform spark ignition with a spark plug, an ultra-lean lean target equivalent ratio is extremely small. Switching between stratified combustion in which combustion is performed and homogeneous combustion in which the target equivalent ratio is relatively large is switched according to the engine operating state. Therefore, when deceleration is performed in the state where stratified combustion is being performed, it is necessary to switch the target equivalent ratio in accordance with switching from stratified combustion to homogeneous combustion. In this case, if the conventional fuel supply control device is applied as it is, the following problems may occur.

(1) If the target equivalent ratio is switched at the same time as switching from stratified combustion to homogeneous combustion, the air amount at the time of switching becomes excessively large, so that the torque rises sharply and the feeling of deceleration may be impaired. (2) In an internal combustion engine equipped with a device such as an exhaust gas recirculation device that introduces part of the exhaust gas into the intake system and recirculates it, immediately after switching due to the effect of device response delay when switching from stratified combustion to homogeneous combustion, Combustion may become unstable.

(3) If the target equivalence ratio is changed during switching from stratified combustion to homogeneous combustion, the target equivalence ratio is intermediate between stratified combustion and homogeneous combustion. , Exhaust properties may be reduced. Accordingly, the present invention has been made in view of the above-described conventional problems, and by smoothly switching the combustion state from stratified combustion to homogeneous combustion during deceleration, torque fluctuation during switching,
An object of the present invention is to provide a fuel supply control device for an internal combustion engine that prevents combustion instability and deterioration in exhaust properties.

[0006]

According to the present invention, as shown in FIG. 1, the combustion state is changed to a stratified combustion state by switching a combustible mixture in a combustion chamber between a stratified state and a homogeneous state. An internal combustion engine that can be switched to a homogeneous combustion mode. When the deceleration is performed during the stratified combustion, the fuel supply is stopped after a first predetermined time has elapsed since the deceleration was started, and the stratified combustion is switched to the homogeneous combustion. In the fuel supply control device for an internal combustion engine that shifts the target equivalent ratio to switch the combustion state, the fuel supply control device for the internal combustion engine is provided with operating state detecting means A for detecting the engine operating state, and according to the detected operating state. Equivalent ratio calculating means B for calculating the target equivalent ratio by using
And a target equivalence ratio correction means C for correcting a change in the target equivalence ratio with respect to the calculated target equivalence ratio, and a condition for switching from stratified combustion to homogeneous combustion based on the corrected target equivalence ratio. And a combustion state switching means E for switching the combustion state from stratified combustion to homogeneous combustion when a condition for switching to homogeneous combustion is satisfied.

According to this configuration, after the target equivalence ratio is set by the target equivalence ratio calculation means in accordance with the operating state, the target equivalence ratio correction means corrects the target equivalence ratio to delay the change of the target equivalence ratio. When the switching condition determination means determines that the switching condition from stratified combustion to homogeneous combustion is satisfied based on the corrected target equivalent ratio, the combustion state switching means switches from stratified combustion to homogeneous combustion.

Therefore, when the combustion state is switched from stratified combustion to homogeneous combustion, the target equivalence ratio gradually changes, so that the air amount does not become excessive immediately after switching to homogeneous combustion, and the torque does not increase. Sharp rise is prevented. According to a second aspect of the present invention, the target equivalence ratio calculating means changes the target equivalence ratio to be calculated from the target equivalence ratio in the stratified charge combustion in the homogeneous combustion when the second predetermined time has elapsed since the start of the deceleration. The control for switching to the target equivalent ratio is performed.

With this configuration, when the second predetermined time has elapsed after the start of deceleration, the target equivalent ratio to be calculated is switched to the target equivalent ratio in homogeneous combustion. Even if a device such as an exhaust gas recirculation device is provided, the response delay of the device at the time of switching is absorbed. According to a third aspect of the present invention, the switching condition determination unit includes a condition establishment prohibition unit that inhibits establishment of a switching condition from stratified combustion to homogeneous combustion until the first predetermined time elapses. .

According to such a configuration, the condition for switching to homogeneous combustion is prohibited from being satisfied until the first predetermined time has elapsed since the start of deceleration, that is, switching to homogeneous combustion is prohibited. Combustion is prevented from occurring at an equivalence ratio between combustion and homogeneous combustion. According to a fourth aspect of the present invention, when the target equivalence ratio corrected by the target equivalence ratio correction device becomes equal to or greater than a predetermined equivalence ratio threshold value, the switching condition determination means switches from stratified combustion to homogeneous combustion. The configuration is such that it is determined that the switching condition is satisfied.

With this configuration, when the corrected target equivalence ratio becomes equal to or greater than the predetermined equivalence ratio threshold value, the condition for switching to homogeneous combustion is satisfied, that is, switching to homogeneous combustion is performed. In addition, the switching condition determination processing is very easily performed. According to a fifth aspect of the present invention, the condition prohibition means includes:
Within the first predetermined time, a limiting means for limiting the target equivalent ratio corrected by the target equivalent ratio correcting means to less than the equivalent ratio threshold is included.

According to this configuration, the corrected target equivalence ratio is limited to less than the equivalence ratio threshold value within the first predetermined time, so that the target equivalence ratio becomes smaller within the first predetermined time,
Since the switching to the homogeneous combustion is not performed, the exhaust properties are improved, and the torque fluctuation when the fuel supply is stopped is suppressed. The invention according to claim 6 is an internal combustion engine capable of switching a combustion state between stratified combustion and homogeneous combustion by switching a combustible mixture in a combustion chamber between a stratified state and a homogeneous state, and decelerates during stratified combustion. When the fuel supply is stopped after a predetermined time has elapsed since the start of deceleration,
In a fuel supply control device for an internal combustion engine that shifts a target equivalence ratio to switch a combustion state from stratified combustion to homogeneous combustion, the engine operation is performed when the fuel supply control device for the internal combustion engine is switched from stratified combustion to homogeneous combustion. The target equivalent ratio calculated according to the state is gradually changed.

With this configuration, when the combustion state is switched from stratified combustion to homogeneous combustion, the target equivalent ratio calculated according to the engine operating state gradually changes. Does not become excessive, and a sharp increase in torque is prevented.

[0014]

As described above, according to the first or sixth aspect of the present invention, when the combustion state is switched from stratified combustion to homogeneous combustion, a sharp increase in torque is prevented.
It is possible to suppress a decrease in the sense of deceleration. According to the second aspect of the invention, when switching the combustion state from stratified combustion to homogeneous combustion, the response delay of the device is absorbed, so that combustion immediately after the switching can be stabilized.

According to the third aspect of the invention, when the combustion state is switched from stratified combustion to homogeneous combustion, combustion is prevented from being performed at an equivalence ratio intermediate between stratified combustion and homogeneous combustion. Exhaust properties in a state where the supply is not stopped can be improved. According to the fourth aspect of the present invention, the switching determination process from the stratified combustion to the homogeneous combustion is performed extremely easily, so that the load on the on-vehicle control device can be reduced.

According to the fifth aspect of the present invention, since the switching to the homogeneous combustion is not performed until the first predetermined time has elapsed, the exhaust characteristics are improved and the torque at the time of stopping the fuel supply is improved. Since the fluctuation is suppressed, the riding comfort can be improved.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the attached drawings. FIG. 2 shows an embodiment in which the fuel supply control device according to the present invention is applied to a direct injection internal combustion engine. First, a direct injection internal combustion engine (hereinafter referred to as "engine")
The configuration of No. 10 will be described. Top surface 11a of piston 11 (hereinafter referred to as “piston top surface”) and cylinder head 1
A combustion chamber 13 having a predetermined volume is formed between the two lower surfaces. Cylinder head 1 located above combustion chamber 13
2, the wall of the cylinder head combustion chamber 13a formed below the cylinder head 12,
Intake port 15 opened and closed by an exhaust valve 16
Exhaust ports 17 which are opened and closed by
Formed one by one.

Between the intake ports 15 of the cylinder head 12, there is provided a fuel injection valve 18 which directs fuel into the combustion chamber 13 with the injection port facing the combustion chamber 13. A spark plug 19 for spark-igniting a combustible mixture of fuel and air is provided substantially at the center of the wall surface of the cylinder head combustion chamber 13a.
Is arranged. The fuel injection valve 1 is provided on the piston top surface 11a.
A cavity 20 having an opening on the upper surface is formed at a position below a line connecting the spark plug 8 and the spark plug 19.

Air is sucked into the combustion chamber 13 of the engine 10 through an air cleaner 21, an intake duct 22, an intake collector 23, an intake port 15, and an intake valve 14. An electronically controlled throttle valve (hereinafter referred to as an “electronically controlled throttle valve”) 24 that changes the opening area of a passage in the intake duct 22 is interposed in the intake duct 22, and an actuator that is controlled based on an engine operating state. Via 25, the intake air flow Q to the engine is controlled.

In the low-load and medium-load regions, fuel spray is injected into the cavity 20 at a later stage of the compression stroke, and a combustible air-fuel mixture is formed below the ignition plug 19 to perform stratified combustion. In the above, fuel spray is injected into the combustion chamber 13 during the intake stroke to form a substantially homogeneous combustible mixture in the combustion chamber 13 and homogeneous combustion is performed. Further, the engine 10 is provided with an evaporative fuel processing device 30 for processing the evaporative fuel generated in the fuel supply system. That is, the fuel tank 3
Evaporated fuel accumulated in the upper space of 1 is guided to the canister 33 via the evaporated fuel passage 32 while the engine 10 is stopped, and is temporarily adsorbed by the adsorbent 33a such as activated carbon in the canister 33. The upper space of the canister 33 is connected to the intake collector 23 via a purge passage 34.
The purge passage 34 is provided with an electronically controlled purge valve 35 for opening and closing the purge passage 34.

Further, the engine 10 is provided with an exhaust gas recirculation device 40 for introducing a part of the exhaust gas into the intake system and recirculating the exhaust gas. That is, the E connected to the exhaust port 17 of the engine 10
Part of the exhaust gas is recirculated to the intake collector 23 through the GR passage 41. The EGR passage 41 has an electronically controlled EG that controls the amount of exhaust gas that is recirculated according to the operating state of the engine.
An R control valve 42 is interposed. By controlling the opening and closing of the EGR control valve 42 according to the engine operating state, the exhaust gas is introduced into the intake collector 23 using the suction negative pressure, and is sucked into the combustion chamber 13 together with the suction air.

Here, a control system of the engine 10 having such a configuration will be described. A control unit 50 with a built-in microcomputer has a potentiometer type accelerator sensor 51 for detecting an accelerator pedal operation amount (hereinafter referred to as "accelerator operation amount") APS, a crank angle sensor 52 for detecting the engine speed Ne, and an engine temperature. A water temperature sensor 53 for detecting the representative cooling water temperature Tw, an air flow meter 54 for detecting the intake air flow rate Q, a potentiometer type throttle valve opening sensor 55 for detecting the throttle valve opening θ of the electronically controlled throttle valve 24, and exhaust air. signal of the O ₂ sensor 56 for detecting the oxygen concentration of the input.

Various sensors such as an accelerator sensor 51 correspond to operating state detecting means, and
0 has functions as a target equivalence ratio calculating means, a target equivalence ratio correcting means, a switching condition determining means, a combustion state switching means, a fulfillment condition prohibiting means and a limiting means. The control unit 50 controls the opening degree θ of the electronically controlled throttle valve 24 and sets the ignition timing in accordance with the operating state detected based on the various signals that have been input, and sets the ignition timing to Controls spark ignition of the mixture.

Next, an outline of the operation of the present embodiment will be described.
This will be described with reference to the timing chart of FIG. This timing chart shows how the target equivalent ratio and the combustion state change when switching from stratified combustion to homogeneous combustion when deceleration is performed during stratified combustion operation. First, when the driver releases the accelerator pedal, the accelerator operation amount falls below a predetermined value, and deceleration is started. That is, when the accelerator operation amount becomes equal to or less than the predetermined value, it is determined that the deceleration has been started.

When the deceleration is started, the basic target equivalence ratio map is not immediately switched from the stratified charge combustion mode to the homogeneous charge combustion map, but a predetermined time DL after the switching control is started.
After the TFM has elapsed, the basic target equivalent ratio map is switched. The predetermined time DLTFM may be a constant or may be set based on an engine operating state such as the engine speed Ne and the target torque tTc. in this way,
If the basic equivalent ratio map is switched from stratified charge combustion to homogeneous charge combustion when a predetermined time DLTFM has elapsed since the start of deceleration, response delay of devices such as the evaporative fuel treatment device 30 and the exhaust gas recirculation device 40 can be achieved. Can be absorbed to prevent unstable homogeneous combustion immediately after switching due to a response delay of the device.

Next, the engine speed Ne and the target torque t
The basic target equivalent ratio TFBYA00 is set with reference to the basic target equivalent ratio map based on Tc. The basic target equivalence ratio map referred to here is referred to for stratified charge combustion until a predetermined time DLTFM has elapsed from the start of deceleration,
After the lapse of the predetermined time DLTFM, reference is made to the one for homogeneous combustion.

Then, phase delay correction is performed on the basic target equivalent ratio TFBYA00, and the corrected target equivalent ratio TFBYA
Set 4. The reason for performing the phase lag correction is that when the basic target equivalent ratio TFBYA00 changes due to a change in the engine operating state, even if the throttle valve is controlled so that the target intake air flow rate matches the change in the basic target equivalent ratio TFBYA00, While the change in the intake air flow rate is delayed due to the delay in the operation of the throttle valve or the volume of the intake system, the fuel injection amount has almost no delay and can follow the change in the basic target equivalent ratio TFBYA00. This is because a delay occurs with respect to a change in the basic target equivalent ratio. Therefore, by performing the phase lag correction, the torque fluctuation at the time of switching from stratified combustion to homogeneous combustion can be made smooth.

The final target equivalence ratio TFBYA0 is equal to the predetermined equivalence ratio TFBYA0 within the cut-in delay time CFD at which the fuel cut is actually started after the deceleration is started.
Limited to DF. That is, the cut-in delay time CF
In D, the correction target equivalent ratio TFBYA4 and the predetermined equivalent ratio T
Compared to FBYADF, the smaller one is the target equivalent ratio TF
Set as BYA0. Then, the target equivalent ratio TFBY
When A0 becomes equal to or higher than the equivalence ratio threshold value TFACH for determining whether to switch from stratified combustion to homogeneous combustion, the combustion flag FSTRR1 is switched to homogeneous combustion. In this way, since the switching of the combustion state from stratified combustion to homogeneous combustion is prohibited within the cut-in delay time CFD, it is possible to prevent a decrease in the exhaust properties until the fuel cut is performed. .

FIGS. 4 and 5 are flow charts showing the contents of the actual switching control of the target equivalent ratio and the combustion state described above. Step 1 (abbreviated as “S1” in the figure)
In the following), it is determined whether or not the engine 10 is decelerating based on the accelerator operation amount APS detected by the accelerator sensor 51. Specifically, when the detected accelerator operation amount APS is equal to or smaller than the predetermined value, it is determined that the engine 10 is decelerating. If the engine 10 is decelerating (Yes), the process proceeds to step 2 and the engine 10 must not be decelerating. (No) Go to step 3.

In step 2, fuel cut control during deceleration is performed. That is, as shown in FIG. 3, the basic injection pulse width is gradually reduced immediately after the start of deceleration, and the basic injection pulse width is set to 0 after the cut-in delay time CFD has elapsed.
Is performed, the fuel cut control is performed.
The fuel cut control in this step is generally performed by an electronically controlled fuel injection device.
The control contents are publicly known.

In step 3, fuel supply control is performed when the vehicle is not decelerating. That is, the basic fuel supply amount Tp is set based on the engine rotation speed Ne, the intake air flow rate Q, and the like, and various corrections are made in consideration of the cooling water temperature Tw and the like, and the effective fuel supply amount Tp
e is calculated, and fuel is injected with a basic injection pulse width corresponding to the effective fuel supply amount Te. Then, this routine ends.

In step 4, the homogeneous combustion switching flag FS
"0" is set to TR0. Homogeneous combustion switching flag FS
TR0 is set to "0" when switching to homogeneous combustion, and "1" to maintain stratified combustion. In step 5, it is determined whether or not a predetermined time DLTFM has elapsed since the start of deceleration, that is, whether or not a predetermined time DLTFM has elapsed since the homogeneous combustion switching flag FSTR0 changed from "1" to "0". When the predetermined time DLTFM has elapsed (Yes), the process proceeds to step 6, where the predetermined time DLTFM
If M has not elapsed (No), the process proceeds to step 7.

At step 6, an equivalent ratio map reference flag FSTR1 is set to "0". The equivalence ratio map reference flag FSTR1 is set to “0” when referring to the homogeneous combustion map, and is set to “1” when referring to the stratified combustion map. In step 7, a map (homogeneous combustion map or stratified combustion map) corresponding to the equivalence ratio map reference flag FSTR1 is selected, and the basic target equivalence ratio TF based on the engine speed Ne and the target torque tTc is selected.
Calculate BYA00. Here, the target torque tTc is:
For example, it is set based on the accelerator operation amount APS and the engine speed Ne. Note that the processing in step 6 corresponds to a target equivalent ratio calculating means.

In step 8, correction control of the intake air flow rate Q is performed. That is, as shown in FIG. 3, by performing control to gradually reduce the throttle opening in consideration of the response delay of the throttle valve, the actual throttle opening changes as indicated by the dotted line in the figure. I do. In step 9, a phase delay correction process is performed on the basic target equivalent ratio TFBYA00. Specifically, the corrected target equivalent ratio after the correction processing is set to T
If FBYA4 is set, the correction is performed by the following equation.

TFBYA4 = FLOAD × TFBYA00 + (1−FLOAD) × TFBYA4 (n−1) Here, FLOAD is a weighted average coefficient set according to the engine operation state, and TFBYA4 (n−1) is This is a correction target equivalent ratio. Note that the processing in step 9 corresponds to a target equivalent ratio correction unit.

In step 10, the combustion determination flag FST
Based on RR, it is determined whether or not stratified combustion is currently in progress,
When the stratified combustion operation is being performed (Yes), the process proceeds to step 11, and when the homogeneous combustion operation is being performed (No), this routine is ended. Note that the combustion determination flag FSTRR is set to “0” during homogeneous combustion, and is set to “1” during stratified combustion.

In step 11, it is determined whether a predetermined time CFD has elapsed since the start of deceleration, that is, whether a predetermined time CFD has elapsed since the homogeneous combustion switching flag FSTR0 changed from "1" to "0". If it is determined that the predetermined time CFD has elapsed (Yes), the process proceeds to step 12, and if the predetermined time CFD has not elapsed (No), the process proceeds to step 13.

In step 12, the target equivalent ratio TFBYA
As 0, the correction target equivalent ratio TFBYA4 is set. In step 13, it is determined whether or not the corrected target equivalent ratio TFBYA4 is equal to or greater than the predetermined equivalent ratio TFBYADF.
If YA4 ≧ TFBYADF (Yes), the process proceeds to step 14, where TFBYA4 <TFBYADF (No)
If so, go to step 12.

In step 14, the target equivalent ratio TFBYA
The predetermined equivalence ratio TFBYADF is set to 0. That is, in the processing of steps 12 to 14, the smaller of the corrected target equivalent ratio TFBYA4 and the predetermined equivalent ratio TFBYADF is selected and set as the final target equivalent ratio TFBFA0. Note that the processing of steps 12 to 14 corresponds to the condition satisfaction prohibiting means, and in particular, the processing of step 14 corresponds to the limiting means.

In step 15, it is determined whether or not to switch the combustion state from stratified combustion to homogeneous combustion. Specifically, the target equivalence ratio TFBYA0 is equal to the equivalence ratio threshold value TFAC.
H is determined to be greater than or equal to H, TFBYA0 ≧ TFAC
If H (Yes), the process proceeds to step 16 where TFBY
If A0 <TFACH (No), this routine ends. Note that the processing in step 15 corresponds to a switching condition determination unit.

In step 16, since all the conditions for switching to homogeneous combustion are satisfied, the combustion determination flag FSTRR is set to "0" (during homogeneous combustion) to switch to homogeneous combustion. Then, combustion control based on the combustion determination flag FSTRR is performed by another routine (not shown) (combustion state switching means). According to such processing, the predetermined time CFD has elapsed since the start of deceleration, and the basic target equivalent ratio T
When the correction target equivalence ratio TFBYA4 obtained by performing the phase delay correction on FBYA00 becomes equal to or higher than the equivalence ratio threshold value TFACH, it is determined that the condition for switching the combustion state from stratified combustion to homogeneous combustion during deceleration is satisfied. You. Therefore,
Since the target equivalent ratio TFBYA0 is gradually switched, torque fluctuation during switching of the combustion state can be smoothed. Further, by delaying the timing of switching the map for calculating the target equivalent ratio TFBYA0, it is possible to absorb a response delay of a device such as an evaporative fuel processing device or an exhaust gas recirculation device, and combustion immediately after the switching becomes unstable. Is prevented. Further, since the switching to the homogeneous combustion is prohibited until the fuel cut is performed at the time of deceleration, it is possible to prevent the deterioration of the exhaust properties.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claim 1 of the present invention.

FIG. 2 is a system configuration diagram showing an embodiment of the present invention.

FIG. 3 is a timing chart showing control contents of the above.

FIG. 4 is a flowchart showing control contents of the above.

FIG. 5 is a flowchart showing control contents of the above.

[Explanation of symbols]

 Reference Signs List 10 in-cylinder internal combustion engine 13 combustion chamber 18 fuel injection valve 50 control unit 51 accelerator sensor 52 crank angle sensor

Claims (6)

[Claims] An internal combustion engine capable of switching a combustion state between stratified combustion and homogeneous combustion by switching a combustible mixture in a combustion chamber between a stratified state and a homogeneous state, wherein deceleration is performed during stratified combustion. A fuel supply control device for an internal combustion engine that stops the fuel supply after a first predetermined time has elapsed from the start of deceleration and shifts a target equivalent ratio to switch the combustion state from stratified combustion to homogeneous combustion. Operating state detecting means for detecting an operating state; target equivalent ratio calculating means for calculating a target equivalent ratio in accordance with the detected operating state; and a method for delaying a change in the target equivalent ratio with respect to the calculated target equivalent ratio. Target equivalent ratio correction means for correcting,
A switching condition determining means for determining whether a condition for switching from stratified combustion to homogeneous combustion is established based on the corrected target equivalence ratio, and a combustion condition for stratified combustion when the condition for switching to homogeneous combustion is satisfied. And a combustion state switching means for switching from a combustion mode to a homogeneous combustion mode. 2. The target equivalence ratio calculating means calculates a target equivalence ratio to be calculated from a target equivalence ratio in stratified combustion to a target equivalence ratio in homogeneous combustion when a second predetermined time has elapsed since the start of deceleration. 2. The fuel supply control device for an internal combustion engine according to claim 1, wherein the control is performed to switch the fuel supply to the internal combustion engine. 3. The switching condition judging means includes a condition satisfaction prohibiting means for prohibiting establishment of a switching condition from stratified combustion to homogeneous combustion until the first predetermined time has elapsed. 3. The fuel supply control device for an internal combustion engine according to claim 1 or 2. 4. The switching condition determining means determines that a condition for switching from stratified combustion to homogeneous combustion is satisfied when the target equivalence ratio corrected by the target equivalence ratio correction means becomes equal to or greater than a predetermined equivalence ratio threshold value. 4. The configuration according to claim 1, wherein the determination is made.
The fuel supply control device for an internal combustion engine according to any one of the above. 5. The condition satisfaction inhibiting means includes limiting means for limiting the target equivalence ratio corrected by the target equivalence ratio correcting means to less than the equivalence ratio threshold value within the first predetermined time. The fuel supply control device for an internal combustion engine according to claim 4, wherein the control device is a fuel supply control device. 6. An internal combustion engine capable of switching a combustion state between stratified combustion and homogeneous combustion by switching a combustible mixture in a combustion chamber between a stratified state and a homogeneous state, wherein deceleration is performed during stratified combustion. Sometimes, the fuel supply is stopped after a lapse of a predetermined time from the start of deceleration, and the fuel supply control device for the internal combustion engine that shifts the target equivalent ratio to switch the combustion state from stratified combustion to homogeneous combustion. A fuel supply control device for an internal combustion engine, wherein a target equivalent ratio calculated according to an engine operating state is gradually changed when switching a combustion state to combustion.