JPH07103049A - Fuel injection control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To completely prevent respectively a misfire from being generated and an NOX generating amount from increasing even when not realized-a desired recirculation rate due to an adjusting delay by actuating together two kinds of fuel injection valves when detected the adjusting delay of recirculated exhaust gas amount. CONSTITUTION:An internal combustion engine is provided with the first fuel injection valve 7 for attaining stratified combustion by directly injecting fuel into a combustion chamber 1 and the second fuel injection valve 10 for attaining uniform combustion by injecting fuel to an intake passage 3 in the downstream of a throttle valve 9. On the other hand, the intake passage 3 in the downstream of the throttle valve 9 communicates with an exhaust passage 5 in an exhaust gas recirculating passage 11, to arrange therein a control valve 12 for controlling a recirculating exhaust gas amount. Here in a control device 20, based on each detection signal from each sensor 21 to 23 for detecting an operating condition of the internal combustion engine, both the fuel injection valves 7, 10 are switched to be actuated. When an adjusting delay of the recirculating exhaust gas amount is detected at switching time, both the fuel injection valves 7, 10 are actuated together.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention particularly has a first exhaust gas recirculation device for directly injecting fuel into a cylinder.
The present invention relates to a fuel injection control device in an internal combustion engine that uses a fuel injection valve and a second fuel injection valve that injects fuel into an intake passage by switching between them according to an engine operating state.

[0002]

2. Description of the Related Art A first fuel injection valve for directly injecting fuel into a cylinder and a second fuel injection valve for injecting fuel into an intake passage are provided. Internal combustion engine that realizes low fuel consumption stratified combustion by using 1 fuel injection valve and realizes uniform combustion by using the 2nd fuel injection valve when operating in the high load side above a predetermined engine load. Is known.

On the other hand, in exhaust gas recirculation, exhaust gas, whose main component is inert gas, is recirculated to the combustion chamber to lower the combustion temperature due to the heat capacity of the inert gas and reduce the amount of NOx produced. It is what makes me. The greater the amount of exhaust gas to be recirculated, the more the NOx reduction effect described above is improved, and the pumping loss can be reduced accordingly. Therefore, the proportion of the exhaust gas amount in the cylinder (hereinafter referred to as EG
It is preferable that the R ratio) be as large as possible. However, since exhaust gas recirculation is accompanied by deterioration of ignitability and combustibility, the EGR rate for each engine load is set to the maximum value within a range where reliable ignitability and desired output are obtained. . The EGR rate set in this way becomes smaller as the engine load increases in the same combustion, and when comparing stratified combustion and uniform combustion, the former has better ignitability. The EGR rate during stratified combustion is higher than that during uniform combustion under the same engine load. The actual control of the EGR rate is performed by controlling the opening degree of the control valve arranged in the exhaust gas recirculation passage.

Therefore, in the internal combustion engine in which the stratified combustion and the uniform combustion are switched as described above, the opening of the control valve changes considerably in order to realize a desired EGR rate at this switching. However, even if the control valve is rapidly opened and closed, the amount of exhaust gas to be recirculated does not immediately increase or decrease, and the desired EGR rate cannot be realized during this period. If it exceeds the desired EGR rate, misfire may occur due to deterioration of ignitability, and if it falls below the desired EGR rate, the amount of NOx generated increases.

Japanese Unexamined Patent Publication No. 63-154816 discloses that both fuel injection valves are used for a predetermined time when switching between stratified combustion and uniform combustion. As a result, when the stratified charge combustion is switched to the uniform burner, the stratified charge combustion is also used for a predetermined time, so that the allowable EG
Even if the R rate rises and exceeds the desired EGR rate, the occurrence of misfire can be prevented. Conversely, when the homogeneous combustion is switched to the stratified combustion, the homogeneous combustion is used for a predetermined time. The air-fuel mixture formed in the peripheral portion of the exhaust gas becomes richer than the over-lean one during stratified combustion, and NOx is less likely to be generated, and the NOx generation amount can be reduced even if the recirculated exhaust gas amount is the same.

[0006]

In the above-mentioned prior art, since the period of time in which both fuel injection valves are used together is always a predetermined time, the engine load change is particularly caused by a predetermined load when switching between stratified combustion and uniform combustion. If it is relatively large, the desired EGR rate may not be obtained even after the lapse of a predetermined time, and the above-mentioned problem still occurs at this time.

Accordingly, an object of the present invention is to have an exhaust gas recirculation device and to inject fuel directly into a cylinder.
In an internal combustion engine that switches between stratified charge combustion using a fuel injection valve and uniform combustion using a second fuel injection valve that injects fuel into an intake passage in accordance with the engine operating state, recirculation exhaust gas Desired EG due to increase / decrease delay
It is an object of the present invention to provide a fuel injection control device capable of completely preventing the occurrence of misfire and the increase in the amount of NOx generated even if the R rate is not realized.

[0008]

A first fuel injection control device for an internal combustion engine according to the present invention is an exhaust gas recirculation device and a first fuel injection control device for directly injecting fuel into a cylinder to realize stratified charge combustion.
A fuel injection valve, a second fuel injection valve for injecting fuel into the intake passage to achieve uniform combustion, and the exhaust gas recirculation device, which are provided in the exhaust gas recirculation device, and have an optimum E according to a combustion method and an engine operating state.
A fuel injection control device for an internal combustion engine, comprising: a control valve that controls an amount of exhaust gas to be recirculated so that a GR rate is realized, the first fuel injection valve and the first fuel injection valve according to an engine operating state. 2 first fuel injection control means for switching between two fuel injection valves to execute fuel injection, detection means for detecting an increase / decrease delay in the amount of recirculated exhaust gas via the control valve when switching fuel injection, and the above detection Second fuel injection control means for executing fuel injection by both of the first and second fuel injection valves while the increase / decrease delay is detected by the means.

A second fuel injection control device for an internal combustion engine according to the present invention is an exhaust gas recirculation device, a first fuel injection valve for injecting fuel directly into a cylinder to realize stratified charge combustion, and an intake air A second fuel injection valve for injecting fuel into the passage to achieve uniform combustion, and the exhaust gas recirculation device are provided in the exhaust gas recirculation device so as to realize an optimum EGR rate according to the combustion method and the engine operating condition. A fuel injection control device for an internal combustion engine, comprising: a control valve for controlling the amount of exhaust gas to be circulated; the fuel injection control device switching between the first fuel injection valve and the second fuel injection valve according to an engine operating state. First fuel injection control means for executing injection, detection means for detecting an increase / decrease delay in the amount of recirculated exhaust gas through the control valve when switching fuel injection, and the increase / decrease delay is detected by the detecting means. While the Switching stopping means for stopping the switching of the fuel injection by the fuel injection control means, characterized by including the capital.

[0010]

The above-described first fuel injection control device for the internal combustion engine is
An exhaust gas recirculation device, a first fuel injection valve for injecting fuel directly into the cylinder to achieve stratified combustion, and a second fuel injection valve for injecting fuel into the intake passage to achieve uniform combustion, Fuel injection control for an internal combustion engine having a control valve provided in an exhaust gas recirculation device, the control valve controlling the amount of exhaust gas to be recirculated so that an optimum EGR rate according to a combustion method and an engine operating state is realized In the device, the first fuel injection control means switches the first fuel injection valve and the second fuel injection valve according to the engine operating state to execute fuel injection, and the detection means transmits the fuel injection via the control valve when switching the fuel injection. Of the recirculation exhaust gas amount is detected, and while the second fuel injection control means detects the increase or decrease delay of the recirculation exhaust gas amount by the detection means, the fuel is supplied by both the first and second fuel injection valves. Let the jet run.

The above-described second fuel injection control device for an internal combustion engine is an exhaust gas recirculation device, a first fuel injection valve for directly injecting fuel into a cylinder to realize stratified charge combustion, and an intake passage. A second fuel injection valve for injecting fuel to achieve uniform combustion and an exhaust gas recirculation device, and recirculates so as to realize an optimal EGR rate according to the combustion method and engine operating conditions. A fuel injection control device for an internal combustion engine, comprising: a control valve for controlling an exhaust gas amount, wherein the first fuel injection control means sets the first fuel injection valve and the second fuel injection valve according to an engine operating state. Switch to execute fuel injection,
The detecting means detects the increase / decrease delay of the recirculated exhaust gas amount via the control valve at the time of switching the fuel injection, and the switching stop means is the first while the detecting means detects the increase / decrease delay of the recirculated exhaust gas amount. Switching of fuel injection by the fuel injection control means is stopped.

[0012]

1 is a schematic sectional view of an internal combustion engine provided with a fuel injection control device according to the present invention. In the figure,
1 is a combustion chamber, 2 is a piston, 3 is an intake passage communicating with the combustion chamber 1 via an intake valve 4, and 5 is a combustion chamber 1 via an exhaust valve 6.
It is an exhaust passage leading to. Reference numeral 7 is a first fuel injection valve for directly injecting fuel into the combustion chamber 1. 8 is a spark plug.

A throttle valve 9 is arranged in the intake passage 3, and a second fuel injection valve 10 for injecting fuel into the intake passage 3 is installed downstream of the throttle valve 9. Further, the throttle valve 9 downstream of the intake passage 3 and the exhaust passage 5 are connected by an exhaust gas recirculation passage 11, and a control for controlling the amount of exhaust gas to be recirculated in the exhaust gas recirculation passage 11. A valve 12 is arranged. Reference numeral 13 is a drive device such as a step motor for driving the control valve 12.

Reference numeral 20 is a control device which is in charge of fuel injection control through the first fuel injection valve 7 and the second fuel injection valve 10 and opening control of the control valve 12 through the drive device 13. An engine such as an accelerator pedal stroke sensor 21 for detecting the amount of depression of an accelerator pedal as an engine load, a rotation sensor 22 for detecting an engine speed, and a cooling water temperature sensor 23 for detecting a cooling water temperature as an engine temperature. A sensor is connected to determine the operating condition.

As already known, the above-mentioned internal combustion engine realizes stratified combustion with low fuel consumption by injecting fuel at the end of the compression stroke using the first fuel injection valve when the load is less than a predetermined value. Further, when the load is equal to or higher than a predetermined load, the second fuel injection valve is used to inject fuel before or during the intake stroke to realize uniform combustion with high output.

The opening of the control valve 12 is controlled by the map shown in FIG. 2 based on the accelerator pedal depression amount L as the engine load detected by the accelerator pedal stroke sensor 21 for each engine revolution. This map shows that for each engine load, the control valve 1 that realizes the maximum EGR rate in the range where reliable ignition performance and desired output are obtained.
The opening degree θ of 2 is set. Therefore, this opening θ is
It is set so that the larger the engine load is, the smaller it becomes in the same combustion. Further, comparing the stratified charge combustion and the uniform combustion, the former has better ignitability. The EGR rate can be made larger than that at the time of uniform combustion under the same engine load, and the opening degree θ is set so as to largely change at the predetermined load L1.

In the control of the opening degree of the control valve 12 as described above, if the engine combustion load range is such that the same combustion is performed, the change in the opening degree of the control valve 12 with respect to the change in the load is relatively small, and the opening degree of the control valve 12 is changed. A corresponding amount of exhaust gas can be recirculated, and the desired EGR at the load after an instantaneous change can be obtained.
The rate can be realized. However, when a load change across the load L1 that switches between stratified combustion and uniform combustion occurs, the change in the opening of the control valve 12 becomes extremely large, and at this time, the amount of exhaust gas to be recirculated immediately increases or decreases to the desired amount. Therefore, the desired EGR rate cannot be realized during this period.

The fuel injection control system of the present embodiment uses the first fuel injection valve 7 and the second fuel injection valve according to the first flow chart shown in FIG.
The fuel injection control by the fuel injection valve 10 is performed. This flow chart is executed every engine revolution. First, at step 101, the accelerator pedal stroke sensor 21 detects the depression amount L of the accelerator pedal as the engine load, the rotation sensor 22 detects the engine speed N, and the cooling water temperature sensor 23 measures the cooling water temperature T as the engine temperature. Is detected.

Next, at step 102, it is judged if the current load L is equal to or higher than the load L1 at which combustion is switched. When this determination is affirmative, the routine proceeds to step 103, where the fuel injection amount Q1 at the time of uniform combustion is determined based on the current load L, the rotational speed N, and the engine temperature T detected at step 101, and the routine proceeds to step 104. move on.

At step 104, it is judged whether the flag F is 0, and when this judgment is affirmed,
This indicates that the combustion in the previous processing is uniform combustion, and the routine proceeds to step 105, and this time also the second fuel injection valve 1
0 is used to execute the fuel injection of the fuel injection amount Q1 determined in step 103, and the flag F is set to 0 in step 106, and the process ends.

On the other hand, when the determination at step 102 is affirmative, the routine proceeds to step 107, where the fuel injection amount at the time of stratified charge combustion is based on the present load L, rotation speed N, and engine temperature T detected at step 101. Q2 is determined and the process proceeds to step 108. In step 108, it is determined whether or not the flag F is 1, and when this determination is affirmative, it indicates that the combustion in the previous processing is stratified combustion, and the process proceeds to step 109, and this time also the first Fuel injection of the fuel injection amount Q2 determined in step 107 is executed using the fuel injection valve 7, and step 110
In, the flag F is set to 1 and the process ends.

When the determination in step 104 is negative, that is, when the previous combustion is not uniform combustion, the routine proceeds to step 111. At this time, it is time to switch from stratified combustion to uniform combustion, and as described above, a decrease delay of the exhaust gas to be recirculated occurs, and the desired EGR rate R shown by the dotted line is obtained as shown in the time chart of FIG. On the other hand, the actual EGR rate R ′ shown by the solid line exceeds it for a while.
In this flowchart, in step 112, the actual EGR rate R ′ is calculated by the following equation (1). R ′ = R ′ − (R′−R) * x1 (1) Here, R ′ on the left side is the previous actual EGR rate, and is initially the EGR rate in the previous stratified charge combustion. R
Is the desired EGR rate in this uniform combustion, x1
Is the reduction rate of the EGR rate in the execution interval of this flowchart.

Next, at step 113, the calculated current actual EGR rate R'and the desired EGR rate R at this time are calculated.
Is judged to be less than or equal to a predetermined value A near 0, and initially this judgment is denied and the routine proceeds to step 113.
The fuel injection amount Q1 determined in step 103 is injected at each injection timing using both the first fuel injection valve 7 and the second fuel injection valve amount, and the flag F is set to 2 in step 114, and the process ends.

In the next processing, since the flag F is set to 2, the determination in step 104 is denied, the processing of step 111 and subsequent steps is repeated, and the determination in step 112 is affirmed, that is, the desired When the EGR rate is substantially achieved, the routine proceeds to step 105, where fuel injection using only the second fuel injection valve 10 is executed.

In this way, the actual EGR rate is equal to the desired EGR in uniform combustion due to the delay in the reduction of the recirculated exhaust gas.
While the fuel consumption is higher than the rate, the fuel injection by the first fuel injection valve 7 is also executed and the stratified charge combustion is also used, so that the allowable EGR rate of combustion is increased and misfire can be prevented.

On the other hand, when the determination in step 108 is negative, that is, when the previous combustion is not stratified combustion, the routine proceeds to step 115. At this time, it is the time when the uniform combustion is switched to the stratified combustion, and the increase in the exhaust gas to be recirculated is delayed as described above, and the desired EGR rate R shown by the dotted line is obtained as shown in the time chart of FIG. On the other hand, the actual EGR rate R ′ shown by the solid line is lower than that for a while.
In this flowchart, in step 110, the actual EGR rate R ′ is calculated by the following equation (2). R ′ = R ′ + (R−R ′) * x2 (1) Here, R ′ on the left side is the previous actual EGR rate, and is initially the EGR rate in the previous uniform combustion. R
Is the desired EGR rate in this stratified combustion, x2
Is the increase rate of the EGR rate in the execution interval of this flowchart.

Next, at step 117, the desired EGR rate R at this time and the calculated current actual EGR rate R '
Is judged to be equal to or smaller than a predetermined value A near 0, and initially this judgment is denied and the routine proceeds to step 117.
The fuel injection amount Q2 determined in step 107 is injected at each injection timing using both the first fuel injection valve 7 and the second fuel injection valve amount, and the flag F is set to 2 in step 118 and the process ends.

In the next processing, since the flag F is set to 2, the determination in step 108 is denied, the processing in step 115 and subsequent steps is repeated, and when the determination in step 110 is affirmed, that is, the desired When the EGR rate is substantially achieved, the routine proceeds to step 109, where fuel injection using only the first fuel injection valve 7 is executed.

In this way, the actual EGR rate is changed to the desired EGR in the stratified charge combustion due to the increase in the recirculated exhaust gas.
While the rate is below the rate, fuel injection by the second fuel injection valve 10 is also executed, and uniform combustion is also used, so that the combustion chamber 1
The air-fuel mixture formed in the surrounding area becomes richer than the over-lean one during stratified combustion, and NOx is less likely to be generated.
The amount of NOx generated can be reduced without recirculating a desired amount of exhaust gas.

The second flow chart shown in FIG. 4 is another flow chart for fuel injection control by the first fuel injection valve 7 and the second fuel injection valve 10. Only the differences from the above-mentioned first flowchart will be described.

In this flowchart, in step 204, it is judged whether or not the flag F is 0, and when this judgment is negative, that is, when the previous combustion is not uniform combustion, the routine proceeds to step 211, where it is the same as described above. The EGR rate R ′ is calculated, and when the determination in step 212 similar to the above is denied, the processing from step 207 onward is executed. That is, the fuel injection amount Q during stratified combustion in the current engine operating state determined in step 207
2 is injected using the first fuel injection valve 7.

As described above, the actual EGR rate is equal to the desired EGR in uniform combustion due to the delay in the reduction of the recirculated exhaust gas.
While the ratio is higher than the above, the fuel is injected by the first fuel injection valve 7 to execute the stratified charge combustion, that is, until the desired EGR ratio is realized as shown in FIG. 7 corresponding to FIG. 5 described above. Since the combustion is not switched, the allowable EGR rate is increased and misfire can be prevented.

On the other hand, in step 208, the flag F
Is judged to be 1, and when this judgment is denied, that is, when the previous combustion is not stratified combustion, the routine proceeds to step 215, where the actual EGR rate R ′ is calculated in the same manner as described above, and the same steps as described above are executed. When the determination in 216 is denied, the processing from step 203 onward is executed. That is, the second fuel injection valve 10 is used to inject the fuel injection amount Q1 at the time of uniform combustion in the current engine operating state determined in step 203.

In this way, the actual EGR rate is changed to the desired EGR in the stratified charge combustion due to the increase in the recirculated exhaust gas.
While the rate is below the range, the second fuel injection valve 10 injects fuel to perform uniform combustion, that is, until the desired EGR rate is realized as shown in FIG. 8 corresponding to FIG. 6 described above. Since the combustion is not switched, the air-fuel mixture formed in the peripheral portion of the combustion chamber 1 becomes richer than the over-lean one at the time of stratified combustion, so that NOx is less likely to be generated and the amount of NOx generated can be reduced. it can.

In the fuel injection in step 113 in the above-mentioned first flow chart, the amount of fuel injected by the first fuel injection valve 7 is actually E with a predetermined amount as the upper limit.
The smaller the difference between the GR rate R'and the desired EGR rate is, the smaller the control is performed, and the amount of fuel injected by the second fuel injection 10 is calculated from the fuel injection amount Q1 determined in step 103. The amount is reduced. Further, the amount of fuel injected by the second fuel injection valve 10 in step 117 is also controlled so as to be gradually reduced,
The amount of fuel injected by the first fuel injection valve 7 is reduced from the fuel injection amount Q2 determined in step 107. As a result, combustion that matches the actual EGR rate can be realized.

However, the present invention is not limited to such fuel injection amount control, and, for example, the second injection in step 117 is performed.
Similarly to the above, the fuel amount injected by the fuel injection valve 10 is set to a predetermined amount as an upper limit, and the actual EGR rate R'and the desired E
The smaller the difference from the GR rate, the smaller the control, and the smaller the fuel injection amount Q2 determined in step 107, and the smaller the fuel injection amount Q2 determined in step 107. As a result, the air-fuel mixture formed in the peripheral portion of the combustion chamber can be made richer, whereby NOx generated at this time can be further reduced.

[0037]

As described above, according to the first fuel injection control apparatus for the internal combustion engine of the present invention, the exhaust gas recirculation apparatus and the first fuel injection control apparatus for directly injecting fuel into the cylinder to realize the stratified charge combustion are provided. A fuel injection valve, a second fuel injection valve for injecting fuel into the intake passage to achieve uniform combustion, and an exhaust gas recirculation device, which are provided in the exhaust gas recirculation device to realize an optimum EGR rate according to the combustion method and engine operating conditions. In the fuel injection control apparatus for the internal combustion engine, the first fuel injection control means includes the first fuel injection valve and the second fuel injection valve according to the engine operating state. The fuel injection valve is switched to perform fuel injection, the detection means detects a delay in the increase / decrease in the amount of recirculated exhaust gas via the control valve at the time of switching the fuel injection, and the second fuel injection control means causes the detection means to re-detect. Delay in increase / decrease in circulating exhaust gas amount The while it is detected first and second
In order to perform fuel injection by both fuel injection valves,
When the desired EGR rate is not realized due to the increase or decrease in the amount of recirculated exhaust gas, and the actual EGR rate exceeds that, in combination with stratified combustion, the allowable EGR rate of combustion is increased to prevent misfire, and when it falls below In order to prevent an increase in the amount of NOx generated, it is possible to prevent NOx from being generated easily by making the air-fuel mixture formed in the peripheral portion of the combustion chamber richer than that in the stratified charge combustion in combination with uniform combustion. it can.

According to the second fuel injection control device for the internal combustion engine of the present invention, the exhaust gas recirculation device and the first fuel injection valve for directly injecting fuel into the cylinder to realize stratified charge combustion. A second fuel injection valve for injecting fuel into the intake passage to achieve uniform combustion and an exhaust gas recirculation device are provided so that an optimum EGR rate according to a combustion method and an engine operating state is realized. A fuel injection control device for an internal combustion engine having a control valve for controlling the amount of exhaust gas to be recirculated, wherein the first fuel injection control means has a first fuel injection valve and a second fuel injection according to an engine operating state. The valve is switched to perform fuel injection, and the detection means detects the increase / decrease delay in the amount of recirculated exhaust gas via the control valve when switching the fuel injection, and
While the fuel injection control means detects the increase / decrease delay of the recirculated exhaust gas amount by the detecting means, the fuel injection control means stops the switching of the fuel injection by the first fuel injection control means. If the actual EGR rate is not achieved and the actual EGR rate exceeds it, stratified charge combustion is continued to prevent misfire as described above, and if lower than that, uniform combustion is sustained to increase NOx generation rate as described above. Can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an internal combustion engine provided with a fuel injection control device according to the present invention.

FIG. 2 is a map for controlling the opening of a control valve.

FIG. 3 is a first flowchart for fuel injection control.

FIG. 4 is a second flowchart for fuel injection control.

FIG. 5: EGR when switching from stratified combustion to uniform combustion
It is a time chart of rate change.

FIG. 6 EGR when switching from uniform combustion to stratified combustion
It is a time chart of rate change.

FIG. 7 is a time chart similar to FIG.

FIG. 8 is a time chart similar to FIG.

[Explanation of symbols]

 1 ... Combustion chamber 2 ... Piston 3 ... Intake passage 5 ... Exhaust passage 7 ... First fuel injection valve 8 ... Spark plug 9 ... Throttle valve 10 ... Second fuel injection valve 11 ... Exhaust gas recirculation passage 12 ... Control valve

Claims (2)

[Claims] 1. An exhaust gas recirculation device, a first fuel injection valve for injecting fuel directly into a cylinder to realize stratified combustion, and a second fuel injection valve for injecting fuel into an intake passage to achieve uniform combustion. Internal combustion engine having a fuel injection valve and a control valve provided in the exhaust gas recirculation device for controlling the amount of exhaust gas to be recirculated so that an optimum EGR rate according to a combustion method and an engine operating state is realized. And a first fuel injection control means for executing fuel injection by switching between the first fuel injection valve and the second fuel injection valve according to an engine operating state. By means of both the detection means for detecting the increase / decrease delay of the recirculated exhaust gas amount through the control valve at the time of switching, and the first and second fuel injection valves while the increase / decrease delay is detected by the detection means. Run fuel injection A fuel injection control device for an internal combustion engine, comprising: a second fuel injection control means; 2. An exhaust gas recirculation device, a first fuel injection valve for injecting fuel directly into a cylinder to realize stratified combustion, and a second fuel injection valve for injecting fuel into an intake passage to achieve uniform combustion. Internal combustion engine having a fuel injection valve and a control valve provided in the exhaust gas recirculation device for controlling the amount of exhaust gas to be recirculated so that an optimum EGR rate according to a combustion method and an engine operating state is realized. And a first fuel injection control means for executing fuel injection by switching between the first fuel injection valve and the second fuel injection valve according to an engine operating state. Detection means for detecting an increase / decrease delay in the amount of recirculated exhaust gas through the control valve at the time of switching, and switching of fuel injection by the first fuel injection control means while the increase / decrease delay is detected by the detecting means. To stop A fuel injection control device for an internal combustion engine, comprising: switching stop means.