JP2000297676A - Fuel injection control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection control device of an internal combustion engine for which engine operation does not become unstable by enabling injection synchronous with air intake to be rapidly switched to injection asynchronous with air intake as necessary, even with heavy fuel. SOLUTION: When fuel is decided to be a heavy fuel (t2), injection in synchronism with air intake (t2 to t3) is temporarily executed after an engine start-up, after which it shifts to injection asynchronous with air intake (t3). Injection synchronous with air intake is temporary and does not rely on coolant temperature or the like. As a result, injection synchronous with the air intake can be switched rapidly to injection asynchronous with the air intake when necessary. Then, the fuel quantity is temporary increased during the switch (t3) to injection asynchronous with the air intake. Accordingly, immediately after the switch to injection asynchronous with air intake, it is possible to prevent the fuel content during air intake from temporarily becoming lean, to prevent the decline in engine output, and maintain stability of engine operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection control apparatus for an internal combustion engine, and more particularly to a fuel injection control apparatus for adjusting a fuel injection timing in accordance with a property of fuel.

[0002]

2. Description of the Related Art When fuel is injected into an intake pipe to supply an air-fuel mixture to a combustion chamber of an internal combustion engine, the injected fuel adheres to an inner wall of the intake pipe, an intake valve, and the like. At this time, when the internal combustion engine is cold, there is a problem that the attached fuel is not sufficiently evaporated and a sufficient amount of fuel is not supplied to the combustion chamber in the subsequent intake stroke. In particular, when the fuel is a heavy fuel having low volatility (for example, a fuel whose volatility has been reduced by adding an anti-knock agent to increase the octane number), this problem becomes remarkable, and a good air-fuel ratio is obtained. Control cannot be performed, and the rotation of the internal combustion engine may become unstable.

In order to solve such a problem of the heavy fuel, the nature of the fuel is determined. If the fuel is a heavy fuel, the fuel injection timing is made closer to the intake stroke as the cooling water temperature of the internal combustion engine is lower. A fuel injection control for injection has been proposed (Japanese Patent Laid-Open No. 3-194149). That is, when the cooling water temperature is the lowest, the fuel injection timing is synchronized with the intake stroke so that heavy fuel is sucked into the combustion chamber at the same time as fuel injection, and is prevented from adhering to the intake pipe inner wall or the intake valve. .

[0004]

However, in the above prior art, it is possible to completely shift to the asynchronous intake injection after the cooling water temperature has risen sufficiently. Therefore, despite the fact that the temperature of the inner wall of the intake pipe and the intake valve has reached a state in which fuel can be evaporated quickly enough, since it depends on the cooling water temperature, the asynchronous intake I can't return. Therefore, the fuel injection is delayed for a long time, and the vaporization time of the fuel mist until the combustion is insufficient, which may cause a problem on the performance of the internal combustion engine such as the fuel consumption rate and the exhaust gas purification rate for a long time.

In order to solve this problem, it is conceivable to execute the intake synchronous injection in a relatively short time without depending on the cooling water temperature, and then immediately shift to the intake asynchronous injection. However, in such a case, the temperature of the inner wall of the intake pipe, the intake valve, and the like may not reach a state where the fuel can be evaporated quickly enough. In such a case, the fuel concentration in the intake air temporarily becomes lean immediately after the shift to the asynchronous intake injection. For this reason, the rotation of the internal combustion engine becomes unstable, and there is a possibility that the idle speed may decrease or the acceleration may be slow.

According to the present invention, even when the fuel is a heavy fuel, it is possible to quickly switch from the intake synchronous injection to the intake asynchronous injection as needed, and the rotation of the internal combustion engine becomes unstable. It is an object of the present invention to provide a fuel injection control device for an internal combustion engine without the above.

[0007]

According to a first aspect of the present invention, there is provided a fuel injection control device for an internal combustion engine which is used for an internal combustion engine which forms a mixture by injecting fuel into an intake passage and supplies the mixture to a combustion chamber. In the injection control device, a fuel determination unit that determines whether the fuel is heavy fuel, and when the fuel determination unit determines that the fuel is heavy fuel, in a period after the start of the internal combustion engine, Fuel injection timing control means for temporarily performing intake synchronous injection in which fuel injection is synchronized with an intake stroke, and thereafter shifting to intake asynchronous injection in which fuel injection is performed before the intake stroke; and With the transition from intake synchronous injection to intake asynchronous injection by
Output increasing means for temporarily performing an output increasing process on the internal combustion engine.

When it is determined that the fuel is heavy fuel, the fuel injection timing control means performs the fuel injection in synchronization with the intake stroke in a period after the internal combustion engine is started, for example, in a period such as idling. The synchronous injection is temporarily executed, and thereafter, the fuel injection is shifted to the intake asynchronous injection that is performed before the intake stroke.

As described above, the intake synchronous injection is temporary, and does not depend on the cooling water temperature or the like. Therefore, it is possible to quickly switch from the intake synchronous injection to the intake asynchronous injection as needed.

With the shift from the synchronous intake injection to the asynchronous intake injection, the output increasing means temporarily performs an output increasing process on the internal combustion engine. Therefore, even in a situation where the fuel concentration in the intake air temporarily becomes lean immediately after the shift to the asynchronous intake injection, the output increase processing is performed on the internal combustion engine to maintain the rotation stability. .

According to a second aspect of the present invention, in the fuel injection control device for an internal combustion engine according to the first aspect, the output increasing means gradually increases the output increasing amount when the output increasing process is completed. It is characterized in that the output increase is eliminated through the process of decreasing.

In this way, when the power increase processing is terminated, the processing is performed so that the power increase is gradually reduced, so that a shock is applied to the rotation of the internal combustion engine as in the case where the power increase suddenly disappears. This does not occur, and can further contribute to the stabilization of the rotation of the internal combustion engine in addition to the effect of the first aspect.

According to a third aspect of the present invention, in the fuel injection control device for an internal combustion engine according to the first or second aspect, the output increasing means temporarily injects fuel into the internal combustion engine as the output increasing process. It is characterized in that the amount is increased.

As described above, the output increasing process includes a process for temporarily increasing the fuel injection amount. Thereby, the operation and effect of claim 1 or 2 can be produced. The fuel injection control device for an internal combustion engine according to claim 4 is
In addition to the configuration according to any one of claims 1 to 3, further comprising a load state detecting means for detecting a load state of the internal combustion engine, wherein the output increasing means includes a load state of the internal combustion engine detected by the load state detecting means. Is larger than the power increase reference value,
The output increase process for the internal combustion engine is not executed.

As described above, the output increasing means does not execute the output increasing process for the internal combustion engine when the load state of the internal combustion engine is larger than the output increase reference value. This is because when the load on the internal combustion engine is increased due to a state such as a large intake flow rate, for example, when the engine is not in the idling state, the fuel concentration is reduced due to switching from the intake synchronous injection to the intake asynchronous injection. This is because the ratio of the influence on the rotational stability of the internal combustion engine becomes extremely small.

Therefore, in addition to the effects of any one of the first to third aspects, by stopping unnecessary control, it is possible to avoid injecting extra fuel or executing other power increase processing. .

According to a fifth aspect of the present invention, there is provided a fuel injection control device for an internal combustion engine, further comprising a rotational speed detecting means for detecting a rotational speed of the internal combustion engine in addition to any one of the first to fourth aspects. Determines whether the fuel is heavy fuel based on the behavior of the rotation speed of the internal combustion engine detected by the rotation speed detecting means at the time of switching between intake synchronous injection and intake asynchronous injection. It is characterized by the following.

As described above, the fuel judging means detects the rotational speed of the internal combustion engine detected by the rotational speed detecting means at the time of switching between intake synchronous injection and intake asynchronous injection performed at any timing. Based on the behavior,
It can be determined whether the fuel is a heavy fuel. For example, the property of the fuel can be determined by detecting the position of the rotation speed of the internal combustion engine, the degree of the rotation speed change, or the increase / decrease of the rotation speed fluctuation when switching between the intake synchronous injection and the intake asynchronous injection.

Thus, in addition to the function and effect of any one of the first to fourth aspects, it is determined whether or not the fuel is heavy fuel without providing a special device for measuring the evaporability of the fuel. be able to.

According to a sixth aspect of the present invention, in addition to the configuration of the fifth aspect, the fuel injection timing control means executes a short-time intake synchronous injection immediately after the start of the internal combustion engine. Thereafter, the process proceeds to intake asynchronous injection, and when the fuel determination unit determines that the fuel is heavy fuel at the time of the transition, the intake synchronous injection is temporarily restarted, and then the operation is returned to intake asynchronous injection. I do.

As described above, the operation shifts from the intake synchronous injection performed for a short time immediately after the start to the intake asynchronous injection. After that, when the fuel determining means determines that the fuel is heavy fuel at this transition, the intake synchronous injection is performed. After the injection is temporarily resumed, the injection timing is controlled so as to return to the intake asynchronous injection. Thereby, the effects of claims 1 to 4 can be obtained.

In addition, the fuel determination means according to claim 5 can be started to determine the nature of the fuel at the timing of shifting from the intake synchronous injection to the intake asynchronous injection immediately after the start. There is no need to provide time for investigating fuel properties. Therefore, in addition to the operation and effect described in the fifth aspect, the fuel injection timing corresponding to the type of fuel can be set immediately after the start, which can further contribute to the rotational stability of the internal combustion engine.

According to a seventh aspect of the present invention, in the fuel injection control device for an internal combustion engine according to the sixth aspect, the fuel injection timing control means may temporarily stop the fuel injection timing when the intake synchronous injection is temporarily restarted. Is gradually changed to the intake synchronization state.

In the case of heavy fuel, when a transition is made from the intake synchronous injection to the intake asynchronous injection immediately after the start, the rotational speed of the internal combustion engine, which has been rapidly increased immediately after the start, is rapidly reduced. Next, since the intake synchronous injection is temporarily restarted, the second rapid increase in the rotational speed may occur regardless of the depression of the accelerator pedal. Such a phenomenon may lead to a deterioration in driving feeling.

However, in the present invention, when the intake synchronous injection is temporarily restarted, the fuel injection timing is gradually changed to the intake synchronous state. For this reason, the second rapid increase in the rotational speed is suppressed. Therefore, the driving feeling can be maintained together with the operation and effect of the sixth aspect.

According to an eighth aspect of the present invention, in addition to the configuration of the sixth or seventh aspect, when the intake-synchronous injection is temporarily restarted by the fuel injection timing control means, the fuel injection control apparatus for the internal combustion engine may temporarily stop the injection. An output reduction means for performing an output reduction process on the internal combustion engine is provided.

As described above, the output reduction means may temporarily reduce the output of the internal combustion engine when the intake synchronous injection is temporarily restarted. The second rapid increase in the rotational speed is suppressed. Therefore, the same operation and effect as those of the seventh aspect are obtained.

According to a ninth aspect of the present invention, in the fuel injection control device for an internal combustion engine according to the eighth aspect, the output decreasing means gradually decreases the output decreasing amount when ending the output decreasing process. It is characterized in that the output decrease is eliminated through the decrease processing.

As described above, when the output reduction process is terminated, the output reduction amount is gradually reduced, so that a shock is applied to the rotation of the internal combustion engine as in the case where the output reduction amount suddenly disappears. This does not occur, and further contributes to the stabilization of the rotation of the internal combustion engine in addition to the effect of the eighth aspect.

According to a tenth aspect of the present invention, in the fuel injection control device for an internal combustion engine according to the eighth or ninth aspect, the output reduction means temporarily controls the intake air for the internal combustion engine as the output reduction process. It is characterized in that the amount is reduced.

As described above, the output reduction processing includes a temporary intake air amount reduction processing. Thereby, the operation and effect according to claim 8 or 9 can be produced.

[0032]

[First Embodiment] FIG. 1 is a block diagram showing a schematic configuration of a gasoline engine to which the above-mentioned invention is applied and a fuel injection control device therefor. A gasoline engine (hereinafter simply referred to as an engine) 1 as an internal combustion engine includes a cylinder block 1a and a cylinder head 1b. The cylinder block 1a includes a plurality of cylinders (four in this embodiment) including the combustion chamber 1c.

Intake port 2 provided for each cylinder
, The air sucked into the intake passage 4 from the air cleaner 3 flows. An injector 5 provided for each cylinder injects fuel to an intake manifold constituting the intake passage 4. The mixture of the intake air and the fuel is introduced into the combustion chamber 1c when the intake port 2 is opened by the intake valve 6 provided for each cylinder.

Further, a spark plug 7 provided for each cylinder is provided.
Is activated, the air-fuel mixture explodes in the combustion chamber 1c.
The piston 8 operates by burning, and the driving force of the engine 1 is obtained. Thereafter, when the exhaust port 9 is opened by the exhaust valve 9 provided for each cylinder, the burned gas is discharged as exhaust gas from the combustion chamber 1c to the exhaust passage 11, further purified by the catalyst 12, and discharged to the outside. You.

The throttle valve 13 provided in the middle of the intake passage 4 operates by operating an accelerator pedal (not shown) to open and close the intake passage 4. The operation of the throttle valve 13 causes the intake air amount Q
Is adjusted. An intake bypass passage 30a is provided in parallel with the throttle valve 13. An ISC valve (hereinafter, referred to as ISCV) 30 for executing idle speed control (hereinafter, referred to as ISC) is provided in the middle of the intake bypass passage 30a.
The opening degree of the ISCV 30 adjusts the amount of intake air Q supplied to the combustion chamber 1c via the intake bypass passage 30a mainly during idling, thereby controlling the engine speed during idling.

An intake air temperature sensor 31 provided in the vicinity of the air cleaner 3 detects the temperature THA of the air taken into the intake passage 4 (intake air temperature) and outputs a signal corresponding to the temperature. An air flow meter 32 provided near the air cleaner 3 detects an intake air amount Q in the intake passage 4 and outputs a signal corresponding to the intake air amount Q. A throttle sensor 33 provided near the throttle valve 13 detects an opening TA (throttle opening) TA of the throttle valve 13 and outputs a signal corresponding to the opening.
The throttle sensor 33 also detects a state where the throttle valve 13 is fully closed.

On the other hand, the oxygen sensor 34 provided in the exhaust passage 11 detects the concentration Ox of oxygen remaining in the exhaust gas and outputs a signal corresponding to the concentration. The water temperature sensor 35 provided in the cylinder block 1a detects the temperature (cooling water temperature) THW of the cooling water flowing for cooling the cylinder block 1a, and outputs a signal corresponding to the temperature.

The distributor 14 is connected to each spark plug 7
To be applied to the ignition signal. Igniter 15
Outputs a high voltage to the distributor 14 in synchronization with a change in the crank angle of the engine 1. The ignition timing of each ignition plug 7 is determined by the output timing of the high voltage in the igniter 15.

A rotation speed sensor 36 provided in the distributor 14 has an engine rotation speed NE based on the rotation of a rotor (not shown) built in the distributor 14.
And outputs a pulse signal corresponding to. Similarly, a cylinder discrimination sensor 37 provided in the distributor 14 detects a reference position of the crank angle of the engine 1 based on the rotation of the rotor, and outputs a signal corresponding to the detection.

Here, an electronic control unit (ECU) 41
Inputs signals output from the various sensors 31 to 37 described above. The ECU 41, based on these input signals,
Each injector 5, igniter 15 and ISCV30
Control.

As shown in the block diagram of FIG.
1 is a central processing unit (CPU) 42, a read-only memory (ROM) 43, a random access memory (RAM) 4
4 and a backup RAM 45 and a timer counter 46. The ECU 41 controls these units 42 to 46
, An external input circuit 47, an external output circuit 48 and the like are connected by a bus 49 to constitute a logical operation circuit. Here, the ROM 43 stores in advance control programs required for various controls such as fuel injection control, ignition timing control, and ISC. The RAM 44 temporarily stores the calculation results of the CPU 42 and the like. The backup RAM 45 stores necessary data even when the power is turned off. The timer counter 46 determines the operation timing and the like in various controls by measuring the time. The external input circuit 47 includes a buffer, a waveform shaping circuit, an A / D converter, and the like, and inputs signals output from various sensors 31 to 37. The external output circuit 48 includes a drive circuit and the like, and outputs necessary drive signals to each injector 5, the igniter 15, and the ISCV 30 at necessary timing.

The CPU 42 executes fuel injection amount control including air-fuel ratio control, fuel injection timing control, ignition timing control, ISC, etc., based on signals from various sensors 31 to 37 input via the external input circuit 47. For this purpose, each injector 5, the igniter 15 and the ISCV 30 are controlled.

In the fuel injection amount control, the amount of fuel injected from each injector 5 is controlled according to the operating state of the engine 1 detected by the air flow meter 32, the oxygen sensor 34, etc., and is suitable for the combustion chamber 1c. An air-fuel mixture with a high fuel concentration is supplied.

In the fuel injection timing control, the timing at which fuel is injected from each injector 5 is controlled in accordance with the operating state of the engine 1 and the nature of the fuel. In this embodiment, in particular, after the engine 1 is started, the intake synchronous injection and the intake asynchronous injection are selected and executed as necessary.

In the ignition timing control, the discharge timing at each ignition plug 7 is controlled according to the operating state of the engine 1. In ISC, engine 1
Is in an idling state, the engine speed is controlled to an appropriate state according to the operating state of the engine 1.

Here, as shown in FIG. 3, the intake-synchronous injection means that the fuel injected from each injector 5 is injected from each injector 5 into the intake passage 4 while the engine 1 is in the intake stroke. Is an injection timing control for immediately flowing into the combustion chamber 1c by the flow of the intake air. As shown in FIG. 3, the asynchronous intake injection is
Before the engine 1 enters the intake stroke, fuel is injected from each injector 5 into the intake passage 4 communicating with each combustion chamber 1c, and thereafter, the fuel evaporated in the intake passage 4 is removed by the flow of intake air in the intake stroke. This is the injection timing control to flow into 1c.

Next, among the various controls executed by the ECU 41, the processing contents of the fuel injection control for controlling the fuel injection amount and the fuel injection timing are shown in the flowchart of FIG. The ECU 41 executes this processing in a time cycle. Each processing step in the flowchart is represented by “S「 ”.

When this process is started, first, for example, the intake air temperature THA, the intake air amount Q, the throttle opening TA, the cooling water temperature THW, the engine speed, based on the detection signals from the sensors 31 to 37 and the like. Each value such as NE and an injection amount increase correction value B described later is read (S10).
0).

Next, the ECU 41 calculates the value of the basic fuel injection amount TAU according to the operating state of the engine 1 based on the values of the various parameters THA, Q, TA, THW, NE, B, etc. read this time ( S110).

Next, it is determined whether the current injection timing is set to intake synchronous injection or intake asynchronous injection (S130). The setting of the intake synchronous injection or the intake asynchronous injection is set based on an injection timing setting process that is executed in parallel with the present fuel injection process from the start of the engine 1 to the start of the engine 1 as described later.

Here, if intake synchronous injection is set, a timing Ta included in the intake stroke as the injection timing Tθ.
(For example, ATDC 60 °) is set (S14).
0). Also, if intake asynchronous injection is set, the injection timing Tθ includes a timing Tb (for example,
(BTDC 75 °) is set (S150). In step S140 or S150, the injection timing Tθ may be further corrected according to the operating state of the engine 1 or the basic fuel injection amount TAU.

Step S140 or step S150
When the injection timing Tθ is set according to
The actual fuel injection amount τ is obtained by making necessary corrections to the basic fuel injection amount TAU obtained at 110 (S160).

Then, control data corresponding to these data is set in the drive circuit of the external output circuit 48 so that the injector 5 injects the actual fuel injection amount τ at the injection timing Tθ (S170).

Thus, the process is once terminated. Thereafter, the fuel injection control process is periodically repeated, and the combustion is controlled at an appropriate fuel injection amount and fuel injection timing according to the operating state of the engine 1.

Here, the start-time injection timing setting processing for deciding between intake synchronous injection and intake asynchronous injection in step S130 will be described. FIGS. 5 and 6 show flowcharts of the start-time injection timing setting process. This processing is executed once each time the ignition switch is turned on.

When the process is started, first, it is determined whether or not the engine 1 has been started by determining an increase in the engine speed NE or the like (S220). While the engine has not been started ("NO" in S220), the determination in step S220 is repeated to wait for the start.

If the engine 1 is started ("Y" in S220)
ES "), intake synchronous injection is set as the injection timing (S222). Then, from the setting of the intake synchronous injection, S0
It is determined whether or not seconds have elapsed (S224). If S0 seconds have not elapsed ("NO" in S224), the determination in step S224 is repeated again. As a result, S0
Wait for seconds. S0 seconds is a short time,
For example, one second is set.

If S0 seconds have elapsed in the intake synchronous injection state ("YES" in S224), then asynchronous intake injection is set as the injection timing (S230). Then, it is determined whether the engine speed NE is smaller than the heavy fuel determination engine speed NE0 (S240). At the time of cold start, during intake asynchronous injection, when the fuel is heavy fuel having low volatility, the engine speed NE drops extremely low. However, the heavy fuel determination speed NE0 is set to the low engine speed. This is a value for determining the state of several NEs.

If NE ≧ NE0 (“N” in S240)
O "), and it is determined whether or not S seconds have elapsed since the start of the asynchronous intake injection in step S230 (S25).
0). For example, a value of several tens of seconds is set as S seconds. S
If the second has not elapsed ("NO" in S250), the process returns to step S240 again to compare the engine speed NE with the heavy fuel determination engine speed NE0.

If the state of NE ≧ NE0 continues for S seconds (“YES” in S250), it is determined that there is no drop in the engine speed NE that occurs when the fuel is heavy, and the start-time injection timing setting processing is terminated as it is. I do. That is, assuming that no heavy fuel is used, the fuel injection timing is set to the intake asynchronous injection immediately after the start.

On the other hand, if NE <NE0 before S seconds elapse ("YES" in S240), it can be estimated that heavy fuel is being used, so that the fuel injection timing is returned to the intake synchronous injection next. (S260) The further reduction of the engine speed NE is prevented. Then, it is determined whether or not C seconds have elapsed in the intake synchronous injection state (S270). As C seconds, for example, a time of about 20 to 40 seconds is set. If C seconds have not elapsed ("NO" in S270), the process returns to step S270 again. That is, it waits for C seconds.

After C seconds have elapsed (“YE” in S270).
S "), because even with heavy fuel, there is no rapid decrease in the engine speed NE immediately after a cold start, the intake asynchronous injection is set as the next injection timing (S280).

Then, it is determined whether or not the current engine load is smaller than the output increase reference value M0 (S29).
0). As the engine load, for example, the air flow meter 3
2 or the throttle opening TA detected by the throttle sensor 33.

When the engine load is large to some extent, there is almost no problem of the engine speed NE dropping due to the switching of the injection timing, and it is not necessary to increase the amount of fuel for preventing the engine speed NE described below from dropping. Accordingly, when the engine load ≧ M0 (“NO” in S290), the start-time injection timing setting process ends.

If the engine load is less than M0 (S2
("YES" at 90) Next, the basic fuel injection amount TAU performed at step S160 of the fuel injection control process described above.
The initial value B is set to the increase correction value B used for the increase correction for
0 is set (S300). Then, it is determined whether or not a short time ΔT has elapsed since the setting of the increase correction value B (S
310). If ΔT has not elapsed (“N” in S310
O "), the determination process of step S310 is repeated. That is, the process waits for a time ΔT.

When ΔT has elapsed (“YE” in S310)
S "), and then the increase correction value B is decreased by a gradually decreasing amount b as shown in the following equation 1 (S320).

[0067]

## EQU1 ## Next, it is determined whether or not the increase correction value B is equal to or less than 0 (S33).
0). If B> 0 ("NO" in S330), the processes of steps S310 and S320 are repeated again. Therefore, thereafter, as long as B> 0 (“NO” in S330),
That is, as long as the increase in the fuel injection amount is substantially present,
The processing of steps S310 and S320 is executed, and b /
At the speed of ΔT, the increase correction value B decreases.

When B ≦ 0 (“YES” in S 330), the start-time injection timing setting process ends. FIG. 7 is a timing chart showing an example of the start-up injection timing setting process when the fuel is heavy fuel.

From time t0 to t1, the engine 1 is started to perform intake synchronous injection (S222), and at time t1 after the start, switching to intake asynchronous injection is performed (S23).
0). Further, immediately after the intake asynchronous injection (time t2), the engine speed NE becomes lower than the heavy fuel determination engine speed NE0 ("YES" in S240). Therefore, the process returns to the intake synchronous injection again (S260).

Thereafter, the intake synchronous injection continues for C seconds (time t2 to t3) and ends at time t3 ("YES" in S270). Then, the mode is switched to the intake asynchronous injection (S280). At this time, even if the injection is switched from the synchronous intake injection to the asynchronous intake injection, the engine speed NE does not drop sharply. The rotation speed NE decreases.

For this reason, at the timing (time t3) at which the synchronous injection is switched to the asynchronous intake injection, the fuel injection amount is increased to maintain the air-fuel ratio and maintain the engine speed NE. FIG. 8 is a timing chart showing an example of the start-time injection timing setting process when the fuel is a light fuel, that is, a fuel having sufficiently high volatility.

That is, between times t10 and t11, the engine 1 is started to perform intake synchronous injection (S22).
2) At time t11 after the start, switching to intake asynchronous injection is performed (S230). However, even immediately after the intake asynchronous injection, the engine speed NE does not fall below the heavy fuel determination engine speed NE0 ("YE" in S250).
S "). Therefore, the intake asynchronous injection is maintained.

Of the processing described above, steps S240 and S240
250 corresponds to processing as fuel determination means, and steps S220 to S230, S260 to S280 correspond to processing as fuel injection timing control means, and steps S300 to S300.
S330 corresponds to a process as output increasing means.

According to the first embodiment described above, the following effects can be obtained. (I). In the start-time injection timing setting process, when it is determined that the fuel is heavy fuel (“YES” in S240), the intake-synchronous injection is temporarily (C seconds) performed during the period after the engine 1 is started. (S260, S270), and thereafter, the process proceeds to intake asynchronous injection (S280). As described above, the intake synchronous injection is temporary, and the engine 1
It does not depend on the cooling water temperature etc. Therefore, it is possible to quickly switch from the intake synchronous injection to the intake asynchronous injection as needed (S280).

With the transition from the intake synchronous injection to the intake asynchronous injection, an output increase process (S300 to S330) is temporarily performed on the engine 1 by increasing the amount of fuel. Therefore, it is possible to prevent the fuel concentration in the intake air from temporarily becoming lean immediately after the shift to the intake asynchronous injection, and to prevent the output of the engine 1 from decreasing. This maintains the stability of the engine rotation.

(B). Output increase processing (S300 to S33
In the case of ending 0), processing is performed so as to gradually decrease the fuel increase. Therefore, the increase correction value B does not suddenly disappear, and no shock occurs in the engine rotation. Therefore, it can further contribute to stabilization of the engine rotation.

(C). When returning to intake asynchronous injection (S2
80), when the load state of the engine 1 (here, the intake air amount Q) is larger than the output increase reference value M0 (S290)
In the case of “NO”, the output increasing process for the engine 1 (S300 to S330) is not executed. That is, when the load of the engine 1 is large, the proportion of the effect of the leaning of the fuel concentration caused by the switching from the intake synchronous injection to the intake asynchronous injection on the rotational stability of the engine 1 becomes extremely small. Because.

For this reason, by stopping unnecessary control, it is possible to prevent unnecessary fuel injection and prevent adverse effects on emissions. (D). The determination of the fuel type is made based on the behavior of the engine speed (here, the position of the engine speed) at the time of switching from the intake synchronous injection to the intake asynchronous injection (S230). As a result, it is possible to determine whether the fuel is a heavy fuel or not, without providing a device for specifically measuring the evaporability of the fuel and the like, without increasing the weight and size of the engine 1.

(E). Immediately after the start, at the timing of transition from intake synchronous injection to intake asynchronous injection (S230), the position of the engine speed is investigated to determine the nature of the fuel. For this reason, it is not necessary to provide a special time for investigating the properties of the fuel. Therefore, the fuel injection timing corresponding to the type of fuel can be set promptly after the start, and this can further contribute to the rotational stability of the engine 1.

[Embodiment 2] The present embodiment 2 is different from FIG.
The second embodiment is different from the first embodiment in that a process as shown in FIG. 9 (steps S410 to 440) is performed instead of the process in step S260 shown in FIG. Other configurations are basically the same as those of the first embodiment. Thus, in the second embodiment, the injection timing is gradually changed from the rotation angle phase of the intake asynchronous injection to the rotation angle phase of the intake synchronous injection.

First, in the process shown in FIG. 5, if "YES" is determined in step S240 and it is estimated that heavy fuel is being used, then, as shown in FIG. Is set (S410). This process is the same as step S260 in the first embodiment.
However, in the second embodiment, the timing Ta initially set as the intake synchronous injection timing is the timing T set as the intake asynchronous injection timing.
The same timing as b is set. Therefore, even if the intake synchronous injection is simply set at the injection timing (S410),
This is substantially an intake asynchronous injection state.

Then, as shown in the following equation 2, a delay process for a minute angle dT is performed on the timing Ta (S42).
0).

[0083]

[Formula 2] Ta ← Ta + dT [Equation 2] Next, the rotational phase at which the timing Ta is actually the intake synchronous injection,
Here, it is determined whether or not the timing is after ATDC 60 ° (crank angle) (S430). If Ta <ATDC60 [deg.] ("N" in S430)
O "), and then a very short time ΔT from the processing in step S420.
Is determined (S432). If ΔT has not elapsed (“NO” in step S432), step S
The determination process at 432 is repeated. That is, it waits for a time ΔT.

If ΔT has elapsed (“YE” in S432)
S "), the retard processing of step S420 is performed again.
Thereafter, as long as “NO” is determined in the step S430, the time waiting process in the step S432 and the step S42
0, and the timing of the intake synchronous injection set in step S140 of FIG. 4 is dT / ΔT
Gradually approaches the timing at which the intake synchronous injection is substantially performed.

If Ta ≧ ATDC60 ° (“YES” in S430), the ATDC 60
Is set (S440), and step S shown in FIG.
Move to the process of 270. The subsequent processing is the same as the processing of the first embodiment.

Here, a processing example in the case of heavy fuel is shown in the timing chart of FIG. Time t20 to t2
Up to 2, the transition is the same as in the first embodiment. However, if it is determined that the fuel is heavy ("YE" in S240).
S ": At time t22), the fuel injection timing does not return instantaneously from intake asynchronous injection to intake synchronous injection, but gradually returns from intake asynchronous injection to intake synchronous injection (time t2).
2 to t23). After time t23, the state changes in the same manner as in the first embodiment.

In the above processing, step S220
To S230, S410 to S440, S270, S280
Corresponds to processing as fuel injection timing control means. Others are as described in the first embodiment.

According to the second embodiment described above, the following effects can be obtained. (I). The effects (a) to (e) of the first embodiment are obtained. (B). In the case of heavy fuel, in a case where the transition from the intake synchronous injection to the intake asynchronous injection is made immediately after the start (time t21), the engine speed once increased immediately after the start is decreased. Then, the intake synchronous injection is temporarily restarted (time t22). However, simply shifting from the intake asynchronous injection to the intake synchronous injection is one point in FIG. 10 depending on the type of engine regardless of the depression of the accelerator pedal. As shown by the difference line, the second rapid increase in the number of revolutions may occur.

In the second embodiment, when the intake synchronous injection is temporarily restarted (time t22), the fuel injection timing is gradually changed to the intake synchronous state (S410 to S44).
0). Therefore, as shown by the solid line in FIG. 10, the second rapid increase in the rotational speed is suppressed. Therefore, the driving feeling can be maintained.

[Third Embodiment] The third embodiment is different from the second embodiment in that the intake air amount reduction control is further performed as shown in FIG. Another configuration is the second embodiment.
Is the same as This intake air amount reduction control is performed when the injection timing temporarily returns from intake asynchronous injection to intake synchronous injection.
This is a process for reducing the intake air amount by correcting the opening of the ISCV 30 to decrease.

If the accelerator pedal is released after the start of the engine 1, the ISC is executed in parallel with the processing of the second embodiment. In this ISC, ISCV3
The engine rotation speed NE is adjusted to an appropriate value by feedback control of the opening degree of 0. The intake air amount reduction control shown in FIG. 11 is a process for temporarily reducing the opening of the ISCV 30 used in this ISC separately from the feedback control.

The intake air amount reduction control is a process started at the timing when step S410 shown in FIG. 9 is executed. When the process is started, first, an initial value A0 is set as the weight reduction correction value A (S510). Next, the weight loss correction value A
It is determined whether or not a short time ΔT has elapsed from the setting (S520). If ΔT has not elapsed (“NO” in S520), the process of step S520 is repeated. That is, waiting for a time of ΔT is performed.

When ΔT has elapsed (“YE” in S520)
S "), and then, as shown in the following equation 3, the decrease correction value A is decreased by the minute value dA (S530).

[0094]

A ← A−dA [Equation 3] Next, it is determined whether the weight loss correction value A is equal to or less than 0 (S54).
0). If A> 0 (“NO” in S540), the process returns to step S520 again, and waits for a time until ΔT has elapsed since the decrease correction value A was set to decrease in the previous step S530 (S520). The decrease correction value A is set to decrease again (S530).

As described above, the weight reduction correction value A becomes dA / Δ
It gradually decreases at the speed of T. As a result, in the ISC being executed in parallel, the decrease correction for the opening degree of the ISCV 30 gradually becomes smaller. Then, if A ≦ 0 (“YES” in S540), 0 is set as the decrease correction value A (S550), and the process ends.

An example of control according to the third embodiment is shown in FIG.
The timing chart is shown in FIG. In the case of the third embodiment, when it is determined that the fuel is heavy after the engine is started, the asynchronous intake injection is gradually switched to the intake synchronous injection (at time t).
32-t33). At the time of this switching, the output of the ISCV 30 is temporarily reduced by temporarily reducing the opening of the ISCV 30 at the same time.

In the above processing, step S510
Steps S550 to S550 correspond to processing as output reduction means.
According to the third embodiment described above, the following effects can be obtained.

(A). The effects (a) and (b) of the second embodiment are obtained. (B). In the third embodiment, as in the case of the second embodiment, when the intake synchronous injection is temporarily restarted (at time t).
From 32 to t33), the fuel injection timing is gradually changed to the intake synchronous injection state (S410 to 440). At the same time, the opening of the ISCV 30 controlled by the ISC is temporarily reduced and corrected. From this, ISC
The second rapid increase in the rotational speed, which cannot be quickly dealt with by the feedback control described above, can be more effectively suppressed. Therefore, the driving feeling can be maintained more favorably.

[Other Embodiments] In the first to third embodiments, the type of fuel is determined based on the value of the engine speed at the time of switching from intake synchronous injection to intake asynchronous injection. In addition, for example, the determination may be made based on the degree of decrease in the engine speed or the degree of increase in the engine speed fluctuation at the same switching.

In the third embodiment, when the fuel injection timing is temporarily returned from intake asynchronous injection to intake synchronous injection,
Although the injection timing is gradually changed and the intake air amount is temporarily reduced, the injection timing may be changed instantaneously and only the intake air amount may be temporarily reduced. Even in this manner, the second rapid increase in the rotational speed is suppressed, and the driving feeling can be maintained.
As another output reduction process, the fuel injection amount may be temporarily reduced, or the ignition timing may be temporarily retarded.

In the first embodiment, when returning from the intake synchronous injection to the intake asynchronous injection when the fuel is heavy fuel, the fuel injection amount is temporarily increased.
The opening degree of the CV 30 may be increased and corrected to temporarily increase the intake air amount.

In step S290 of the first embodiment, the engine load was directly investigated.
The degree of the engine load may be determined based on whether or not the engine is idling. That is, if the vehicle is idling, “YES” is determined in step S290,
The process may proceed to the output increasing process (S300 to S330), and if it is not the idling state, “NO” may be determined in step S290 and the process may be terminated.

Although the embodiments of the present invention have been described above, the embodiments of the present invention include the following various technical items in addition to the technical items described in the claims. It should be noted that it has.

(1). After starting the internal combustion engine, the fuel injection control device for the internal combustion engine temporarily executes the intake synchronous injection in which the fuel injection is synchronized with the intake stroke, and thereafter switches the fuel injection to the intake asynchronous injection performed before the intake stroke. And fuel determination means for determining whether the fuel is heavy fuel, and when the fuel determination means determines that the fuel is heavy fuel, if intake synchronous injection is being performed, intake synchronous injection is performed. A fuel injection timing control means for temporarily resuming intake synchronous injection when the mode has already been shifted to intake asynchronous injection, and an intake air extended or temporarily resumed by the fuel injection timing control means. A fuel injection control device for an internal combustion engine, comprising: output increasing means for temporarily performing an output increasing process on the internal combustion engine at the end of synchronous injection.

(2). 3. The fuel injection control device for an internal combustion engine according to claim 1, wherein the output increasing unit temporarily increases the intake air amount to the internal combustion engine as the output increasing process.

(3). 10. The fuel injection control device for an internal combustion engine according to claim 8, wherein the output reduction unit temporarily reduces the fuel injection amount for the internal combustion engine as the output reduction process.

(4). In addition to the configuration according to any one of claims 1 to 3, further comprising an idling state detecting means for detecting whether or not the internal combustion engine is in an idling state, wherein the output increasing means is configured to detect whether the internal combustion engine is in an idling state by the idling state detecting means. A fuel injection control device for an internal combustion engine that does not execute an output increasing process for the internal combustion engine when it is detected that the fuel injection control is not performed.

[0108]

In the fuel injection control apparatus for an internal combustion engine according to the first aspect, the fuel injection timing control means, when it is determined that the fuel is heavy fuel, for a period after the start of the internal combustion engine, for example, During a period such as idling, intake synchronous injection in which fuel injection is performed in synchronization with the intake stroke is temporarily executed, and thereafter, there is a shift to intake asynchronous injection in which fuel injection is performed before the intake stroke. As described above, the intake synchronous injection is temporary, and does not depend on the cooling water temperature or the like.
Therefore, it is possible to quickly switch from the intake synchronous injection to the intake asynchronous injection as needed. Then, with the transition from the intake synchronous injection to the intake asynchronous injection, the output increasing means temporarily performs an output increasing process on the internal combustion engine. Therefore, even in a situation where the fuel concentration in the intake air temporarily becomes lean immediately after the shift to the asynchronous intake injection, the output increase processing is performed on the internal combustion engine to maintain the rotation stability. .

According to a second aspect of the present invention, in the fuel injection control device for an internal combustion engine according to the first aspect, the output increasing means gradually increases the output increasing amount when the output increasing process is completed. After that, the output increase is eliminated. As described above, when the power increase process is terminated, the output increase amount is gradually reduced, so that a shock may occur in the rotation of the internal combustion engine as when the output increase amount suddenly disappears. Therefore, in addition to the effect of the first aspect, it is possible to further contribute to stabilization of the rotation of the internal combustion engine.

In the fuel injection control device for an internal combustion engine according to the third aspect,
The output increasing means temporarily increases the fuel injection amount for the internal combustion engine as the output increasing process. As described above, the output increasing process includes a process of temporarily increasing the fuel injection amount. Thereby, the effect of claim 1 or 2 can be produced.

According to a fourth aspect of the present invention, there is provided a fuel injection control apparatus for an internal combustion engine, further comprising a load state detecting means for detecting a load state of the internal combustion engine, The means does not execute the output increase processing for the internal combustion engine when the load state of the internal combustion engine detected by the load state detection means is larger than the output increase reference value. As described above, the output increasing unit does not execute the output increasing process for the internal combustion engine when the load state of the internal combustion engine is larger than the output increase reference value. This is because when the load on the internal combustion engine is increased due to a state such as a large intake flow rate, for example, when the engine is not in the idling state, the fuel concentration is reduced due to switching from the intake synchronous injection to the intake asynchronous injection. This is because the ratio of the influence on the rotational stability of the internal combustion engine becomes extremely small. For this reason, in addition to the effect of any one of the first to third aspects, by stopping unnecessary control, it is possible to avoid injecting extra fuel or executing other output increase processing.

A fuel injection control device for an internal combustion engine according to a fifth aspect of the present invention further includes, in addition to any one of the first to fourth aspects, a rotational speed detecting means for detecting a rotational speed of the internal combustion engine, The means determines whether the fuel is heavy fuel based on the behavior of the rotation speed of the internal combustion engine detected by the rotation speed detection means when switching between the intake synchronous injection and the intake asynchronous injection. You are going to. As described above, the fuel determination means is based on the behavior of the rotation speed of the internal combustion engine detected by the rotation speed detection means at the time of switching between intake synchronous injection and intake asynchronous injection performed at any timing. Thus, it can be determined whether the fuel is a heavy fuel. For example, the property of the fuel can be determined by detecting the position of the rotation speed of the internal combustion engine, the degree of the rotation speed change, or the increase / decrease of the rotation speed fluctuation when switching between the intake synchronous injection and the intake asynchronous injection. Thereby, in addition to the effect of any one of claims 1 to 4,
It is possible to determine whether the fuel is a heavy fuel or not, without providing a device for measuring the evaporability of the fuel.

According to a sixth aspect of the present invention, in addition to the configuration of the fifth aspect, the fuel injection timing control means executes a short-time intake synchronous injection immediately after the start of the internal combustion engine. After that, the process shifts to intake asynchronous injection, and when the fuel determination unit determines that the fuel is heavy fuel at the time of the shift, the intake synchronous injection is temporarily resumed, and then the operation is returned to the intake asynchronous injection. . As described above, the operation shifts from the intake synchronous injection performed for a short time immediately after the start to the intake asynchronous injection, and thereafter, when the fuel determination unit determines that the fuel is heavy fuel at this transition, the intake synchronous injection is temporarily stopped. After the restart, the injection timing is controlled so as to return to the intake asynchronous injection. Thereby, claim 1
~ 4 effects can be produced. In addition, the fuel determination means according to claim 5 can be activated to determine the nature of the fuel at the timing of transition from the intake synchronous injection to the intake asynchronous injection immediately after the start of the engine. There is no need to provide time to investigate properties. For this reason, in addition to the effect described in claim 5, the fuel injection timing corresponding to the type of fuel can be set quickly after the start, which can further contribute to the rotational stability of the internal combustion engine.

According to a seventh aspect of the present invention, in the fuel injection control device for an internal combustion engine, the fuel injection timing control means may include a fuel injection control device for temporarily resuming the intake synchronous injection. The timing is gradually changed to the intake synchronous state. In the case of heavy fuel, when a shift is made from the intake synchronous injection to the intake asynchronous injection immediately after the start, the internal combustion engine speed, which once rises rapidly immediately after the start, rapidly decreases. And
Next, since the intake-synchronous injection is temporarily restarted, the second rapid increase in the rotational speed may occur regardless of the depression of the accelerator pedal. Such a phenomenon may lead to a deterioration in driving feeling. However, in the present invention, when the intake synchronous injection is temporarily restarted, the fuel injection timing is gradually changed to the intake synchronous state. For this reason, the second rapid increase in the rotational speed is suppressed. Therefore, the driving feeling can be maintained together with the effect of the sixth aspect.

In the fuel injection control device for an internal combustion engine according to the eighth aspect, in addition to the configuration of the sixth or seventh aspect, when the intake-synchronous injection is temporarily restarted by the fuel injection timing control means, the fuel injection timing control means temporarily stops the injection. Is provided with output reduction means for performing output reduction processing on the internal combustion engine. As described above, the output reduction means may temporarily perform the output reduction processing on the internal combustion engine when the intake synchronous injection is temporarily restarted. The rapid increase in the number of revolutions is suppressed. Therefore, the same effect as the seventh aspect is obtained.

According to a ninth aspect of the present invention, in the fuel injection control device for an internal combustion engine according to the eighth aspect, the output decreasing means gradually decreases the output decreasing amount when ending the output decreasing process. Through the process of reducing the output, the output reduction is eliminated. As described above, when the output reduction process is ended, the output reduction amount is gradually reduced, so that a shock may occur in the rotation of the internal combustion engine as if the output reduction amount suddenly disappeared. Therefore, in addition to the effect of claim 8, it is possible to further contribute to stabilization of the rotation of the internal combustion engine.

According to a tenth aspect of the present invention, in the fuel injection control device for an internal combustion engine according to the eighth or ninth aspect, the output reduction means temporarily takes in the internal combustion engine as the output reduction processing. The air volume is to be reduced. As described above, the output reduction process includes a temporary intake air amount reduction process. Thereby, the effect of claim 8 or 9 can be produced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a gasoline engine and a fuel injection control device according to a first embodiment.

FIG. 2 is a block diagram showing a control system of the fuel injection control device.

FIG. 3 is an explanatory diagram of timings of intake synchronous injection and intake asynchronous injection.

FIG. 4 is a flowchart of a fuel injection control process performed by the fuel injection control device.

FIG. 5 is a flowchart of a startup injection timing setting process performed by the fuel injection control device.

FIG. 6 is a flowchart of a startup injection timing setting process performed by the fuel injection control device.

FIG. 7 is a timing chart showing an example of a start-up injection timing setting process when the fuel is heavy fuel in the first embodiment.

FIG. 8 is a timing chart showing an example of a start-up injection timing setting process when the fuel is light fuel in the first embodiment.

FIG. 9 is a flowchart of a start-time injection timing setting process performed by the fuel injection control device in the second embodiment.

FIG. 10 is a timing chart showing an example of a start-up injection timing setting process when the fuel is heavy fuel according to the second embodiment.

FIG. 11 is a flowchart of an intake air amount reduction control process performed by a fuel injection control device in a third embodiment.

FIG. 12 is a timing chart showing an example of a start-up injection timing setting process and an intake air amount reduction control process when the fuel is heavy fuel in the third embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 1a ... Cylinder block, 1b ... Cylinder head, 1c ... Combustion chamber, 2 ... Intake port, 3 ... Air cleaner, 4 ... Intake passage, 5 ... Injector, 6 ... Intake valve, 7 ... Spark plug, 8 ... Piston , 9 ... exhaust valve, 10 ... exhaust port, 11 ... exhaust passage, 12 ... catalyst,
13 ... Throttle valve, 14 ... Distributor,
15: igniter, 30: idle speed control valve (ISCV), 30a: intake bypass passage, 31:
Intake air temperature sensor, 32: air flow meter, 33: throttle sensor, 34: oxygen sensor, 35: water temperature sensor,
36: rotation speed sensor, 37: cylinder discrimination sensor, 41: electronic control unit (ECU), 42: central processing unit (CP)
U), 43 read-only memory (ROM), 44 random access memory (RAM), 45 backup RAM, 46 timer counter, 47 external input circuit, 48 external output circuit, 49 bus.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) NA08 NC08 ND01 NE01 NE04 NE06 NE09 NE12 NE23 PA01Z PA10Z PA11Z PA14A PA14Z PA17Z PB02B PB02Z PD03A PE01Z PE03Z PE04Z PE08Z

Claims (10)

[Claims] 1. A fuel injection control device for use in an internal combustion engine that forms a fuel-air mixture by injecting fuel into an intake passage and supplies the mixture to a combustion chamber, and determines whether the fuel is heavy fuel. Fuel determination means; and, when the fuel determination means determines that the fuel is heavy fuel, temporarily executes intake synchronous injection in which fuel injection is synchronized with an intake stroke during a period after the start of the internal combustion engine. After that, the fuel injection timing control means shifts to the intake asynchronous injection in which the fuel injection is performed before the intake stroke, and, with the shift from the intake synchronous injection to the intake asynchronous injection by the fuel injection timing control means, temporarily. A fuel injection control device for an internal combustion engine, comprising: an output increasing unit that performs an output increasing process on the internal combustion engine. 2. The power increase means according to claim 1, wherein, when ending said power increase processing, the output increase is eliminated through processing for gradually decreasing the output increase amount.
A fuel injection control device for an internal combustion engine according to claim 1. 3. The fuel injection control device for an internal combustion engine according to claim 1, wherein the output increasing unit temporarily increases the fuel injection amount to the internal combustion engine as the output increasing process. . 4. A load condition detecting means for detecting a load condition of an internal combustion engine, wherein the load increasing means is detected by the load condition detecting means. A fuel injection control device for an internal combustion engine, wherein an output increase process for the internal combustion engine is not executed when a load state of the internal combustion engine is larger than an output increase reference value. 5. In addition to the configuration according to any one of claims 1 to 4, further comprising a rotation speed detection means for detecting a rotation speed of the internal combustion engine, wherein the fuel determination means is provided between an intake synchronous injection and an intake asynchronous injection. A fuel injection control device for an internal combustion engine, which determines whether or not fuel is heavy fuel based on the behavior of the rotation speed of the internal combustion engine detected by the rotation speed detection means at the time of switching. . 6. The fuel injection timing control means executes a short-time synchronous intake injection immediately after the start of the internal combustion engine, and then shifts to intake asynchronous injection. At the time of the shift, the fuel determining means determines that the fuel is heavy fuel. 6. The fuel injection control device for an internal combustion engine according to claim 5, wherein when it is determined that the injection is synchronous, the intake synchronous injection is temporarily restarted, and then the operation is returned to the intake asynchronous injection. 7. The internal combustion engine according to claim 6, wherein the fuel injection timing control means gradually changes the fuel injection timing to the intake synchronous state when the intake synchronous injection is temporarily restarted. Fuel injection control device. 8. An output reduction for temporarily performing an output reduction process on an internal combustion engine when the fuel injection timing control means temporarily resumes intake synchronous injection, in addition to the configuration of claim 6 or 7. And a fuel injection control device for an internal combustion engine. 9. The output reduction unit according to claim 8, wherein, when terminating the output reduction process, the output reduction is canceled through a process of gradually reducing the output reduction amount.
A fuel injection control device for an internal combustion engine according to claim 1. 10. The fuel injection control device for an internal combustion engine according to claim 8, wherein the output reduction unit temporarily reduces the intake air amount for the internal combustion engine as the output reduction process. .