JP2003083116A - Control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress generation of a torque difference in level and to improve fuel economy and exhaust performance, in an internal combustion engine provided with a variable valve timing device. SOLUTION: This internal combustion engine is provided with the variable valve timing device. In a transient operation condition in which valve timing is changed (S1 to S5), correction quantity of intake air quantity is calculated according to a change of valve timing and the opening of a throttle is adjusted according to the correction quantity (S6 and S7). Fuel injection quantity is adjusted according to a difference of target intake negative pressure to be generated in the operation condition at that time and a detected actual intake negative pressure (S8 to S12).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine equipped with a variable valve timing device, and more particularly to control in a transient state where the actual valve timing changes.

[0002]

2. Description of the Related Art In an internal combustion engine equipped with a variable valve timing device that variably controls the opening / closing timing (valve timing) of an intake valve or an exhaust valve, as a technique for suppressing a torque step generated when switching valve timing,
For example, there is one described in JP-A No. 11-324733.

This engine calculates the required torque to be generated by the engine on the basis of a preset three-dimensional map of accelerator opening, engine rotation speed and required torque, and calculates the engine rotation speed set in advance. By calculating the required throttle opening based on the three-dimensional map of the required torque and the required throttle valve opening, the change in the generated engine torque is smoothed.

[0004]

However, the above-mentioned three-dimensional map is necessary for the valve timing in the steady state set according to the accelerator opening and the engine rotation speed, or the engine rotation speed and the required torque. Since the torque or the required throttle opening is obtained, there are the following problems.

In a transitional operating region in which the actual valve timing changes momentarily according to the change in the target valve timing, even if the throttle opening and the engine rotation speed are the same, the actual valve timing changes in accordance with the change. Since the amount of intake air in the cylinder changes, a feeling of a step difference in the generated torque occurs.
That is, in the above-mentioned conventional technique, the torque step in the steady state can be suppressed, but the torque step in the transient state cannot be sufficiently suppressed.

Further, the fuel injection amount is calculated on the basis of the intake air amount detected by the intake air amount detecting means provided on the upstream side of the collector.
Since the intake response delay due to the inertia of the intake system volume is not taken into consideration, a deviation from the actual cylinder intake air amount occurs. Therefore, rebound such as lean / rich air-fuel ratio occurs.

The present invention has been made in view of the above problems, and suppresses the occurrence of a torque step even under a transient operating condition where the valve timing is changed, and improves the fuel consumption and the exhaust performance. The purpose is to let.

[0008]

Therefore, an invention according to claim 1 is a control device for an internal combustion engine equipped with a variable valve timing device, wherein the valve timing is changed under transient operating conditions in which the valve timing changes. It is characterized in that the throttle opening is adjusted so as to suppress the fluctuation of the intake air amount while estimating the intake air amount taken into the cylinder based on the throttle opening and the engine rotation speed.

The invention according to claim 2 is characterized in that the throttle opening is adjusted according to the difference between the estimated intake air amount and the intake air amount detection value detected on the upstream side of the throttle valve. The invention according to claim 3 is characterized in that the estimation of the intake air amount is performed with reference to a three-dimensional map of the throttle opening, the engine rotation speed, and the valve timing.

According to a fourth aspect of the present invention, there is provided a control device for an internal combustion engine equipped with a variable valve timing device, wherein the valve timing, the throttle opening, the engine rotation speed, and the engine speed are changed under a transient operating condition in which the valve timing changes. The target intake negative pressure is calculated based on the above, and the fuel injection amount is adjusted based on the difference between the calculated target intake negative pressure and the intake negative pressure detection value.

According to a fifth aspect of the present invention, the difference between the target intake negative pressure and the actual intake negative pressure with respect to the basic fuel injection amount set based on the intake air amount detected on the upstream side of the throttle valve is determined. It is characterized in that the correction is performed in accordance therewith. The invention according to claim 6 is characterized in that the target suction negative pressure is calculated with reference to a three-dimensional map of the throttle opening, the engine rotation speed, and the valve timing.

The invention according to claim 7 is characterized in that the variation of the intake air amount sucked into the cylinder is suppressed by adjusting the throttle opening degree with respect to the change of the valve timing.

[0013]

According to the invention of claim 1, based on the valve timing, the throttle opening and the engine speed,
The throttle opening is adjusted so that the actual intake air amount does not fluctuate based on the estimated intake air amount while estimating the intake air amount taken into the cylinder. It is possible to improve an unintended torque step and improve fuel efficiency and exhaust performance without rebounding drivability.

According to the second aspect of the present invention, the throttle opening is adjusted according to the difference between the estimated intake air amount and the intake air amount detection value detected on the upstream side of the throttle valve. It is possible to suppress a torque step and a lean / rich spike caused by a response delay. According to the invention of claim 3, the cylinder intake air amount can be easily estimated by creating a three-dimensional map of the throttle opening, the engine rotation speed, and the valve timing in advance.

Further, such a map is used for the control according to the second aspect of the present invention, and the throttle opening that makes the estimated intake air amount constant is obtained from the map with respect to the detected engine speed and valve timing. It is also possible to directly control the throttle valve. According to the invention of claim 4, the target suction negative pressure is calculated based on the valve timing, the throttle opening, and the engine rotation speed, and the target suction negative pressure is calculated according to the difference between the calculated target suction negative pressure and the suction negative pressure detection value. By adjusting the fuel injection amount, the fuel injection amount according to the actual cylinder intake air amount can be set, and the lean / air ratio of the air-fuel ratio can be adjusted.
Fuel efficiency can be improved without the bouncing of enrichment.

According to the fifth aspect of the present invention, the target intake negative pressure and the detected actual intake negative pressure are set with respect to the basic fuel injection amount set based on the intake air amount detection value having a response delay. Since the correction is performed in accordance with the difference between, the fuel injection amount can be set in consideration of the fluctuation amount between the detected intake air amount and the air amount actually sucked into the cylinder, and the fluctuation of the air-fuel ratio can be suppressed.

The cylinder intake air amount is estimated based on the difference between the target intake negative pressure and the detected actual intake negative pressure.
It is also possible to directly set the fuel injection amount based on the estimated cylinder intake air amount. According to the sixth aspect of the present invention, the target suction negative pressure can be easily calculated by creating the three-dimensional map of the throttle opening, the engine rotation speed, and the valve timing in advance.

According to the invention of claim 7, it is possible to suppress the torque step and the lean / rich spike that occur due to the change of the valve timing, and also suppress the fluctuation of the air-fuel ratio, so that the fuel efficiency and the exhaust performance can be further improved. .

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram of an engine according to an embodiment of the present invention, and FIG. 2 is a control block diagram. 1 and 2
In the intake passage 2 of the engine 1, the air cleaner 3, the air flow meter 4, the throttle valve 5,
A collector 6 is provided. The air flow meter 4 detects the flow rate of the passing air (intake air amount Qa), and the throttle valve 5 opens its valve opening (throttle opening TVO).
The air flow rate is controlled by.

Each cylinder of the engine 1 is provided with a fuel injection valve 8 for injecting fuel into the combustion chamber 7, and a spark plug 9 for performing spark ignition in the combustion chamber 7, which is sucked in via an intake valve 10. Fuel is injected from the fuel injection valve 8 to the generated air to form a mixture, which is compressed in the combustion chamber 7 and ignited by spark ignition by a spark plug 9.

Combustion exhaust gas is discharged from the combustion chamber 7 to the exhaust passage 12 via the exhaust valve 11 and released into the atmosphere via an exhaust purification catalyst and a muffler (not shown). The intake valve 10 and the exhaust valve 11 are opened and closed by cams provided on the intake side cam shaft 13 and the exhaust side cam shaft 14, respectively. The intake-side camshaft 13 is provided with a variable valve timing device 15 that variably controls the opening / closing timing (valve timing) of the intake valve 10 by changing the rotational phase of the camshaft with respect to the crankshaft.

As such a variable valve timing device, a publicly known device can be used, so a detailed description thereof will be omitted. For example, there is a device described in Japanese Patent Laid-Open No. 10-18869. The variable valve timing device 15 controls the opening / closing timing of the intake valve 10 by advancing / retarding, thereby controlling the period in which both the intake valve 10 and the exhaust valve 11 are open (valve overlap amount). it can.

The ECU 30 includes an air flow meter (AFM) 4 and a suction negative pressure sensor 1 for detecting a suction negative pressure.
6, a water temperature sensor 17 for detecting the engine cooling water temperature, a throttle opening sensor 18 for detecting the opening of the throttle valve 5, an accelerator opening sensor 1 for detecting the accelerator opening
The signal from 9 is input. Further, the engine rotation speed Ne calculated by the rotation speed calculation circuit 34 based on the signal from the crank angle sensor 20, the crank angle sensor 20
Also, the current operating angle (actual VTC operating angle) of the intake side camshaft 13 calculated by the Valtai calculation circuit 35 based on the signal from the cam angle sensor 21 is input.

Then, the ECU 30 basically calculates the torque to be generated by the engine based on the input accelerator opening signal and the input engine speed Ne, and based on the calculated torque and the engine speed Ne. The target throttle opening and target operating angle (target VTC operating angle) are set, and AF
According to the intake air amount Qa detected in M4, the basic fuel injection amount (basic fuel injection pulse width) Tp is set so as to obtain a predetermined air-fuel ratio.

The air amount control circuit 31 controls the throttle valve 5 so that the target throttle opening degree is obtained, and the fuel injection control circuit 32 controls the fuel injection valve 8 to inject the fuel which is set to change the variable valve. The control circuit 33 uses the intake camshaft 13
The variable valve timing device 15 is controlled so that is the target operating angle (VTC target angle). Here, in the present embodiment, under transient operating conditions in which the valve timing changes momentarily, first, the throttle opening TVO is adjusted to change the intake air amount actually sucked into the cylinder. I try to suppress it.

Then, the fluctuation of the air-fuel ratio is suppressed by accurately injecting the amount of fuel corresponding to the amount of air actually sucked into the cylinder. The intake air amount control and the fuel injection amount control according to the present invention will be described below. First, the intake response delay will be described. FIG. 3 shows changes in the in-cylinder intake air amount, the collector 6 outlet air flow rate, and the air flow meter 4 passing air flow rate due to advance control of the valve timing of the intake valve 10 (VTC advance control).

In the figure, the engine operating condition changes from a VTC non-operating region to a VTC operating region, for example, from a low / medium speed / low load region to a low / medium speed / high load region by accelerating with a constant throttle opening (TVO). When the transition is made, the phase angle of the intake side camshaft 13 changes from the position of the most retarded angle to the target VTC angle for a short time (t
The transition (advance) is made in 1 to t2). Then intake valve 10
Of the intake air amount in the cylinder even if the throttle opening TVO and the engine speed Ne are the same, because the closing timing IVC of the Will increase. Therefore, a torque step that the driver does not intend occurs.

The air flow rate at the outlet of the collector 6 increases by the amount of increase in the cylinder intake air amount, but a response delay ta due to inertia of the intake system volume from the intake valve 10 to the collector 6 occurs. Although the flow rate of the air passing through the AFM 4 increases by the increase in the in-cylinder intake air amount, similarly, a response delay tb due to the intake system volume from the intake valve 10 to the AFM 4 occurs.

Therefore, the increase in the in-cylinder intake air amount due to the VTC advance control is not reflected in the air flow rate passing through the AFM 4 instantaneously due to the influence of the response delay (intake response delay). Therefore, more air temporarily flows into the cylinder than the intake air amount Qa detected by the AFM4, but the fuel injection amount Tp is the intake air amount Q detected by the AFM4.
Since it is set based on a, a lean spike occurs.

When the vehicle is decelerated by turning off the throttle,
The operating condition of the engine is from the VTC operating range to the VTC non-operating range,
For example, when shifting from the low / medium speed / high load region to the low / medium speed / low load region, the phase angle of the intake side camshaft 13 shifts from the advanced position to the most retarded position in a short time (delay angle). To do. At this time, contrary to the case of FIG. 3 described above, the throttle opening T
Even if the VO and the engine rotation speed Ne are the same, the amount of intake air in the cylinder decreases, so that a torque step that the driver does not intend occurs.

The decrease of the intake air amount in the cylinder is instantaneously caused by the influence of the response delay due to the inertia of the intake system volume.
Since it is not reflected in the flow rate of air passing through M4, less air than the amount detected by AFM4 temporarily flows into the cylinder, and a rich spike occurs. Therefore, during the VTC operation in which the valve timing changes, the throttle opening TVO is adjusted so as to suppress the fluctuation of the cylinder intake air amount.

Specifically, the throttle opening TVO, the engine rotation speed Ne, and the valve timing (actual VTC operating angle) are detected, and the cylinder intake air amount (estimated intake air amount Qt) sucked into the cylinder at this time is detected. ) Is estimated. Then, the throttle opening TVO is adjusted according to the difference between the estimated intake air amount Qt and the intake air amount Qa having the response delay detected by the AFM 4, thereby suppressing the variation of the in-cylinder intake air amount.

With respect to the detected engine speed Ne and the detected valve timing (actual VTC operating angle), the throttle opening is calculated so as to keep the cylinder intake air amount immediately before the valve timing changed, and the throttle opening is obtained. The valve 5 may be directly controlled. This suppresses the occurrence of torque step and the occurrence of lean / rich spike. Therefore, in the present embodiment, when the control for advancing the valve timing of the intake valve 10 (VTC advance control) is being performed, the throttle opening is adjusted in the direction of narrowing, and the control for delaying the valve timing ( When VTC retard control) is being performed, the throttle opening is adjusted in the opening direction.

Further, at the time of VTC advance control and immediately after the end of control, the intake air negative pressure is in the process of developing due to the influence of the intake response delay. Even if is adjusted, it cannot be said that the intake air amount Qa detected by the AFM 4 sufficiently reflects the fluctuation of the in-cylinder intake air amount actually sucked into the cylinder.

Therefore, in order to suppress the fluctuation of the air-fuel ratio and improve the fuel consumption performance and the exhaust performance, the actual cylinder intake air amount is estimated more accurately, and based on this estimated cylinder intake air amount. It is necessary to set the fuel injection amount. Where V
The fluctuation of the intake negative pressure, the fluctuation of the intake air amount, and the fluctuation of the required value of the fuel injection amount in the steady state due to the TC advance control have a relationship as shown in FIG. 4, and the intake air amount corresponding to the intake negative pressure. It is possible to obtain the required fuel injection amount.

Therefore, the actual in-cylinder intake air amount may be accurately estimated in consideration of the undeveloped intake negative pressure to set the fuel injection amount directly.
The basic fuel injection amount Tp set on the basis of the intake air amount Qa detected in M4 is corrected according to the undeveloped amount of the suction negative pressure to suppress the fluctuation of the air-fuel ratio.

Specifically, the throttle opening TVO, the engine speed Ne, the valve timing (actual VTC operating angle) are detected, and the preset throttle opening TVO,
Referring to the three-dimensional map of the engine speed Ne and the valve timing, the target suction negative pressure (target B) that should be generated in that state
ost) is calculated. Then, an actual intake negative pressure (actual Boost) having a calculated target intake negative pressure (target Boost) and a response delay detected by the intake negative pressure sensor 16.
The set basic fuel injection amount (fuel injection pulse width) Tp is corrected in accordance with the difference between and.

The target suction negative pressure (target Boost) is the suction negative pressure that should be generated in a steady state under the engine operating conditions at that time. As a result, lean / rich air-fuel ratio can be prevented and fuel efficiency can be improved. Therefore, in the present embodiment, the throttle opening is adjusted so as to suppress the fluctuation of the in-cylinder intake air amount, and thus the set basic fuel injection amount Tp is decreased during the VTC advance angle control and immediately thereafter. Corrected to the direction, VTC
During the retard control and immediately thereafter, the set basic fuel injection amount Tp is adjusted to increase.

The above control is shown in the flow chart of FIG. In step 1, it is determined whether or not the VTC operation permission condition is satisfied. If the VTC operation permission condition is satisfied, the process proceeds to step 2, and if not, this control is ended. In step 2, the engine speed Ne, the fuel injection amount (fuel injection pulse width) Tp, and the actual VTC operating angle are read.

In step 3, the target VTC operating angle is calculated. This is calculated by the Valtai arithmetic circuit 35 based on the operating conditions of the engine. In step 4, it is determined whether or not the difference (absolute value) between the target operating angle and the actual operating angle is equal to or more than the VTC control dead zone Δθ. This control ends.

In step 5, the variable valve timing device 15 rotates the intake camshaft 13 to the target VTC operating angle, and valve timing control is executed. In step 6, the required correction air amount according to the actual VTC operating angle is calculated. Specifically, an estimated value (estimated in-cylinder intake air amount) Qt of the intake air amount taken into the cylinder is calculated, and
The actual intake air amount Qa is detected by the AFM 4, and the difference Δ
Calculate Q (required corrected air amount).

Here, the estimated in-cylinder intake air amount Qt is
The throttle opening TVO, the engine speed Ne, and the valve timing (actual VTC operating angle of the intake camshaft 13) are detected and calculated by referring to a three-dimensional map as shown in FIG. 6, for example. In step 7, the intake air amount is corrected. Specifically, the estimated in-cylinder intake air amount Qt and AFM
The throttle opening ΔTVO corresponding to the difference ΔQ from the intake air amount Qa detected in 4 is calculated, and the opening of the throttle valve 5 is adjusted by ΔTVO.

As a result, the fluctuation of the in-cylinder intake air amount due to the VTC advance angle control or the retard angle control is prevented, and the occurrence of the torque step and the lean / rich spike are suppressed. In step 8, the current suction negative pressure (actual Boost) is detected by the suction negative pressure sensor 16. In step 9, a target suction negative pressure (target Boost) is calculated.

Here, the target suction negative pressure is detected by detecting the throttle opening TVO, the engine speed Ne and the valve timing (actual VTC operating angle of the intake side cam shaft 13), and for example, as shown in FIG. It is calculated by referring to the dimension map. In step 10, a difference (absolute value) between the target suction negative pressure and the current suction negative pressure is calculated, and it is determined whether or not the difference is equal to or larger than the suction negative pressure correction threshold ΔPb.

[0045] For example, this control ends without correcting the fuel injection amount. In step 11, the fuel injection amount correction value ΔTp corresponding to the difference between the target intake negative pressure and the current intake negative pressure is calculated by searching a table or the like shown in FIG.

In step 12, the fuel injection amount correction value ΔTp calculated in step 11 is subtracted from the basic fuel injection amount (basic fuel injection pulse width) Tp set based on the intake air amount Qa detected by the AFM 4. The basic fuel injection amount Tp is corrected with. Then, the corrected fuel injection amount (fuel injection pulse width) Tp ′ is output to execute the fuel injection.

This makes it possible to inject a quantity of fuel that corresponds to the actual cylinder intake air quantity, and prevent rebound of the lean / rich air-fuel ratio. FIG. 9 compares a time chart of this control during VTC advance control with that of the conventional control. The VTC advance angle control may be, for example, idle stop or start acceleration from self-propelling, or re-acceleration from coasting deceleration (idle SW ON).

As shown in the figure, in the conventional control, VTC
Since the throttle opening TVO is constant during the advance control, as described above, the suction negative pressure (Boost) decreases, and the cylinder intake air amount temporarily increases sharply and then increases as the volume efficiency improves. To do. Since the basic fuel injection amount (basic fuel injection pulse width) Tp is set according to the intake air amount Qa detected by the air flow meter 4, it does not reflect the fluctuation of the cylinder intake air amount. Therefore, when the amount of intake air in the cylinder increases suddenly, a lean spike occurs and a torque step occurs.

On the other hand, in this control, the throttle opening TVO is corrected so as to be reduced so as to suppress the increase in the in-cylinder intake air amount due to the advance of the VTC operation angle, so that the torque step and the lean spike are generated. Can be suppressed. For the fuel injection amount (fuel injection pulse width) Tp ′, the basic fuel injection amount Tp (broken line) set according to the intake air amount Qa detected by the air flow meter 4 is calculated by using the target intake negative pressure (target Boost:
The correction is set according to the difference between the broken line) and the actual negative suction pressure (real Boost: solid line). As a result, the fuel injection amount can be set according to the actual cylinder intake air amount.

FIG. 10 compares a time chart of this control during VTC retard control with that of the conventional control. The VTC retard control may be, for example, accelerator deceleration from a partial range (VTC operating condition) or shift UP with constant accelerator acceleration. The VT
Contrary to the C advance control, in the conventional control, the intake negative pressure (Boost) increases during the VTC retard control, and the cylinder intake air amount temporarily decreases sharply, and then the decrease in volume efficiency decreases. To do. Therefore, a rich spike occurs and a torque step occurs when the in-cylinder intake air amount is temporarily reduced.

On the other hand, in this control, the throttle opening TVO is adjusted in the opening direction so as to suppress the decrease in the cylinder intake air amount due to the VTC retardation control. As a result, it is possible to suppress the occurrence of torque step and the occurrence of rich spike. The fuel injection amount (fuel injection pulse width) Tp ′ is the intake air amount Qa detected by the air flow meter 4 as in the VTC advance control.
The basic fuel injection amount Tp (broken line) set in accordance with the above is corrected and set according to the difference between the target intake negative pressure (target Boost: broken line) and the actual intake negative pressure (actual Boost: solid line). As a result, the fuel injection amount can be set according to the actual cylinder intake air amount.

In the above description, the internal combustion engine in which the valve timing of the intake valve is variably controlled has been described, but the invention is not limited to this. For example, in the internal combustion engine in which the valve timing of the intake valve and the exhaust valve is variably controlled. Can also be applied. In this case, the valve timing of the intake valve and the exhaust valve is detected as the valve timing.

[Brief description of drawings]

FIG. 1 is a diagram showing a system configuration of an embodiment of the present invention.

FIG. 2 is a control block diagram of the same.

FIG. 3 is a diagram showing changes in an in-cylinder intake air amount, a collector outlet air flow rate, and an AFM passing air flow rate according to a VTC advance control.

FIG. 4 is a diagram showing changes in intake negative pressure, intake air amount, and fuel injection amount with changes in valve overlap amount.

FIG. 5 is a flowchart showing intake air amount control and fuel injection amount control of the present invention.

FIG. 6 is a diagram showing an example of a map for calculating a predicted value Qt of a cylinder intake air amount.

FIG. 7 is a diagram showing an example of a map for calculating a target suction negative pressure.

FIG. 8 is a diagram showing an example of a table for calculating a fuel injection correction amount ΔTp.

FIG. 9 is a time chart (A) of conventional control and a time chart (B) of control according to the present invention during VTC advance control.

FIG. 10 is a time chart (A) of conventional control and a time chart (B) of control according to the present invention during VTC retard control.

[Explanation of symbols]

1 Internal combustion engine 2 Intake passage 4 Air flow meter (AFM) 5 Throttle valve 6 collector 7 Combustion chamber 8 fuel injection valves 10 Intake valve 11 Exhaust valve 13 Intake side camshaft 14 Exhaust side camshaft 15 Variable valve timing device 16 Suction negative pressure sensor 18 Throttle opening sensor 20 crank angle sensor 21 Cam angle sensor 30 ECU

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 41/18 F02D 41/18 E 43/00 301 43/00 301H 301K 301Z F term (reference) 3G084 BA00 BA05 BA09 BA13 BA23 CA00 DA05 DA10 DA11 FA07 FA10 FA20 FA33 FA38 3G092 AA01 AA06 AA11 BA02 BA04 BB01 DA01 DA08 DA12 DC03 DE03S FA04 FA06 FA15 FA24 GA11 HA01Z HA05X HA05Z HA06Z HA13X HB01X HE01Z HE03Z HE01Z04G14 MA01 MA11 NC02 PA01Z PA07Z PA11Z PB03Z PE01Z PE03Z

Claims (7)

[Claims] 1. A control device for an internal combustion engine, comprising a variable valve timing device, comprising: an in-cylinder cylinder based on a valve timing, a throttle opening, and an engine speed under a transient operating condition in which the valve timing changes. A control device for an internal combustion engine, wherein the throttle opening is adjusted so as to suppress the fluctuation of the intake air amount while estimating the intake air amount sucked into the engine. 2. The control of an internal combustion engine according to claim 1, wherein the throttle opening is adjusted according to the difference between the estimated intake air amount and the intake air amount detection value detected on the upstream side of the throttle valve. apparatus. 3. The estimation of the intake air amount is performed by referring to a three-dimensional map of throttle opening, engine speed, and valve timing. Control device for internal combustion engine. 4. A control device for an internal combustion engine, comprising a variable valve timing device, wherein a target intake negative value is based on a valve timing, a throttle opening and an engine speed under a transient operating condition where the valve timing changes. A control device for an internal combustion engine, which calculates a pressure and adjusts a fuel injection amount based on a difference between the calculated target intake negative pressure and a detected value of the intake negative pressure. 5. A basic fuel injection amount set on the basis of an intake air amount detected on the upstream side of a throttle valve is corrected according to a difference between the target intake negative pressure and an actual intake negative pressure. The control device for an internal combustion engine according to claim 4, wherein 6. The target suction negative pressure is a throttle opening,
The control device for an internal combustion engine according to claim 4 or 5, wherein the control device is calculated by referring to a three-dimensional map of the engine rotation speed and the valve timing. 7. The method according to any one of claims 4 to 6, wherein the variation of the intake air amount sucked into the cylinder is suppressed by adjusting the throttle opening degree with respect to the change of the valve timing. 1. A control device for an internal combustion engine according to any one of the above.