JP3988450B2 - Control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an internal combustion engine that controls the intake air amount by changing the valve opening / closing operation conditions of both intake valves and intake / exhaust valves of the internal combustion engine.
[0002]
[Prior art]
In recent years, an internal combustion engine mounted on a vehicle is provided with a variable valve mechanism that continuously varies a valve opening / closing operation condition such as a lift amount of an intake valve, and the valve opening / closing operation condition depends on an accelerator opening degree or an engine operating state. It has been proposed that the intake air amount is controlled by varying the opening area and opening time of the suction port of the cylinder by varying. In the intake air amount control by this variable valve control, since the intake air amount sucked into the cylinder can be directly controlled by the intake port of the cylinder, compared with the intake air amount control by the conventional throttle valve control, the throttle valve to the cylinder is controlled. There is no response delay of the air system, the response of the intake air amount control is improved, and there is no need to throttle the intake passage with a throttle valve, so that there is an advantage that the pumping loss can be reduced and the fuel consumption can be improved.
[0003]
In addition, there is an engine that employs an automatic engine stop / start device (so-called idling stop device) for the purpose of reducing fuel consumption, reducing exhaust emissions, and reducing noise. This automatic engine stop / start device, for example, automatically stops the engine when the driver stops the vehicle, and then the driver tries to start the vehicle (for example, brake release operation). The engine is automatically started when it goes.
[0004]
[Problems to be solved by the invention]
By the way, in the intake air amount control by the variable valve control described above, the intake air amount sucked into the cylinder is directly controlled by the intake port of the cylinder. Therefore, the intake air amount is compared with the intake air amount control by the conventional throttle valve control. The time delay until the change of the intake air amount due to the control (variable valve control) is detected by the air flow meter upstream of the intake pipe is increased. For this reason, the intake air amount is controlled with variable valve control, especially during complicated and highly variable transient operations, such as immediately after the start of the engine (immediately after the complete explosion), when the engine speed suddenly increases or decreases and then reaches a stable state. It is difficult to stably control with good response. For this reason, if the intake air amount control by variable valve control is executed immediately after the engine is started, the intake air amount control becomes unstable at the time when the operation state immediately after the engine is not stabilized, thereby causing a torque shock or an air-fuel ratio change. Invitation may lead to deterioration of drivability and exhaust emissions.
[0005]
In vehicles equipped with the aforementioned automatic engine stop / start device, the automatic stop / start of the engine is frequently repeated when driving in urban areas. As a result, drivability and exhaust emission are deteriorated every time the automatic start is performed, and this is a problem that cannot be ignored due to the frequency.
[0006]
The present invention has been made in view of such circumstances. Therefore, the object of the present invention is to control the intake air amount after automatic start of the internal combustion engine in a system in which the intake air amount is controlled by variable valve control. It is an object of the present invention to provide a control device for an internal combustion engine that can stabilize the engine and prevent deterioration of drivability and exhaust emission after automatic start of the internal combustion engine.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a control apparatus for an internal combustion engine according to claim 1 of the present invention is provided with an air flow meter provided in an intake passage of the internal combustion engine and a downstream side of the air flow meter in the intake passage. A throttle valve, a variable valve control means for controlling at least the intake air amount by varying the valve opening / closing operation conditions of both the intake valve and the intake / exhaust valve of the internal combustion engine provided on the downstream side of the throttle valve; Automatic start control means for automatically starting the internal combustion engine when a predetermined automatic start condition is satisfied during the automatic stop of the engine, and a predetermined time until the rotational speed of the internal combustion engine after the automatic start of the internal combustion engine reaches a stable state period (hereinafter referred to as "variable valve control prohibition period") to the intake valve or the variable valve system of the valve opening and closing operation condition of the valve lift amount and the like between the two valve intake and exhaust While it is fixed to a predetermined condition by prohibiting means, in which so as to control the intake air quantity by controlling the opening degree of the throttle valve in the throttle control means located between the intake valve and the air flow meter.
[0008]
In this configuration, the variable valve control prohibition period after the automatic start of the internal combustion engine, that is, a period including a complicated and highly variable transition period immediately after the automatic start, the valve opening / closing operation conditions are fixed and the suction by the variable valve control is performed. The air amount control is prohibited, and instead, the intake air amount is controlled by the throttle valve control, which has a smaller detection delay of the intake air amount during the transition than the variable valve control. As a result, the intake air amount can be stably controlled by the throttle valve control when the operation state after the automatic start of the internal combustion engine is not stable, and the deterioration of the drivability and the exhaust emission after the automatic start of the internal combustion engine is prevented. can do.
[0009]
In this case, if the difference between the target valve opening / closing operation condition initially set at the time of automatic start of the internal combustion engine and the valve opening / closing operation condition fixed in the variable valve control prohibition period after completion of the automatic start is large, the internal combustion engine is automatically started. Before and after the completion, the valve opening / closing operation condition changes drastically and suddenly, the sudden change of the valve opening / closing operation condition may appear as a torque shock or exhaust emission deterioration.
[0010]
Therefore, as in claim 2, it is preferable to fix the valve opening / closing operation condition to the target valve opening / closing operation condition at the time of automatic starting of the internal combustion engine during the variable valve control prohibition period after completion of the automatic starting of the internal combustion engine. In this way, the valve opening / closing operation condition can be maintained constant before and after the completion of the automatic start of the internal combustion engine, and the change in the valve opening / closing operation condition can be eliminated. Emission deterioration can be prevented.
[0011]
Further, the variable valve control prohibition period after the automatic start of the internal combustion engine may be a fixed value set in advance. However, as described in claims 3 and 4 , the variable valve control prohibition period may be changed according to the number of automatic stop or automatic start of the internal combustion engine. A control prohibition period may be set. In this way, for example, when the number of automatic stops (or the number of automatic starts) of the internal combustion engine after the start of traveling is small, it is determined that the frequency of adverse effects such as drivability due to variable valve control and deterioration of exhaust emissions is low. As a result, it is possible to shorten the variable valve control prohibition period and to start variable valve control at an early stage after the automatic start so that priority is given to performance improvement such as fuel efficiency improvement by variable valve control. When the number of automatic stops (or the number of automatic starts) of the internal combustion engine after the start of traveling increases, it is determined that the frequency of adverse effects due to variable valve control has increased, and the variable valve control prohibition period is lengthened. Thus, it is possible to perform control such that prevention of adverse effects by variable valve control is given priority over performance improvement by variable valve control.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, a schematic configuration of the entire engine control system will be described with reference to FIG. An air cleaner 13 is provided at the most upstream portion of the intake pipe 12 of the engine 11 that is an internal combustion engine, and an air flow meter 14 that detects the intake air amount is provided downstream of the air cleaner 13. On the downstream side of the air flow meter 14, a throttle valve 15 whose opening is adjusted by a DC motor or the like and a throttle opening sensor 16 for detecting the throttle opening are provided.
[0013]
Further, a surge tank 17 is provided on the downstream side of the throttle valve 15, and an intake pipe pressure sensor 18 for detecting the intake pipe pressure is provided in the surge tank 17. The surge tank 17 is provided with an intake manifold 19 for introducing air into each cylinder of the engine 11, and a fuel injection valve 20 for injecting fuel is attached in the vicinity of the intake port of the intake manifold 19 of each cylinder. Yes. A spark plug 21 is attached to each cylinder of the engine 11 for each cylinder, and the air-fuel mixture in the cylinder is ignited by spark discharge of each spark plug 21.
[0014]
Further, the intake valve 28 and the exhaust valve 29 of the engine 11 are provided with variable valve lift mechanisms 30 and 31 for varying the valve lift amount, respectively. Further, the intake valve 28 and the exhaust valve 29 may each be provided with a variable valve timing mechanism that varies the valve timing (opening / closing timing).
[0015]
On the other hand, the exhaust pipe 22 of the engine 11 is provided with a catalyst 23 such as a three-way catalyst for reducing CO, HC, NOx and the like in the exhaust gas. / Air-fuel ratio sensor 24 (linear air-fuel ratio sensor, oxygen sensor, etc.) for detecting lean is provided. A cooling water temperature sensor 25 that detects the cooling water temperature and a crank angle sensor 26 that detects the engine rotation speed are attached to the cylinder block of the engine 11.
[0016]
Outputs of these various sensors are input to an engine control circuit (hereinafter referred to as “ECU”) 27. The ECU 27 is mainly composed of a microcomputer, and executes various control programs stored in a built-in ROM (storage medium), thereby allowing the fuel injection amount and ignition of the fuel injection valve 20 according to the engine operating state. The ignition timing of the plug 21 is controlled.
[0017]
Next, the configuration of the variable valve lift mechanism 30 of the intake valve 28 will be described based on FIGS. Note that the variable valve lift mechanism 31 of the exhaust valve 29 has substantially the same configuration as the variable valve lift mechanism 30 of the intake valve 28, and thus description thereof is omitted.
[0018]
As shown in FIG. 2, a link arm 34 is provided between a camshaft 32 for driving the intake valve 28 and a rocker arm 33, and a stepping motor (not shown) is provided above the link arm 34. A control shaft 35 that is rotationally driven is provided. The control shaft 35 is provided with an eccentric cam 36 so as to be integrally rotatable, and the link arm 34 swings via a support shaft (not shown) at a position eccentric with respect to the axis of the eccentric cam 36. It is supported movably. A swing cam 38 is provided at the center of the link arm 34, and a side surface of the swing cam 38 is in contact with an outer peripheral surface of a cam 37 provided on the cam shaft 32. Further, a pressing cam 39 is provided at the lower end portion of the link arm 34, and the lower end surface of the pressing cam 39 is in contact with the upper end surface of the roller 40 provided at the central portion of the rocker arm 33.
[0019]
Accordingly, when the cam 37 rotates due to the rotation of the cam shaft 32, the swing cam 38 of the link arm 34 moves to the left and right following the outer peripheral surface shape of the cam 37, and the link arm 34 swings to the left and right. . When the link arm 34 swings left and right, the pressing cam 39 moves left and right. Therefore, the roller 40 of the rocker arm 33 moves up and down according to the lower end surface shape of the pressing cam 39, and the rocker arm 33 swings up and down. Move. The intake bubble 28 moves up and down by the up and down movement of the rocker arm 33.
[0020]
On the other hand, when the eccentric cam 36 is rotated by the rotation of the control shaft 35, the position of the support shaft of the link arm 34 is moved, and the initial contact point position between the pressing cam 39 of the link arm 34 and the roller 40 of the rocker arm 33 ( (See FIGS. 3 and 4). Further, as shown in FIG. 2, the lower end surface of the pressing cam 39 of the link arm 34 has a curvature at a left side so that the pressing amount of the rocker arm 33 is 0 (the valve lift amount of the intake valve 28 is 0). A curved surface 39a is formed, and the pressing curved surface 39b is formed with such a curvature that the amount of pressing of the rocker arm 33 increases (the valve lift amount of the intake valve 28 increases) from the base curved surface 39a to the right.
[0021]
As shown in FIG. 3, in the high lift mode in which the valve lift amount of the intake valve 28 is increased, the initial contact between the pressing cam 39 of the link arm 34 and the roller 40 of the rocker arm 33 by the rotation of the control shaft 35. Move the point position to the right. Thereby, when the pressing cam 39 moves to the left and right due to the rotation of the cam 37, the section of the lower end surface of the pressing cam 39 that contacts the roller 40 moves to the right, so that the maximum pressing amount of the rocker arm 33 increases. As a result, the maximum valve lift amount of the intake valve 28 increases, the period during which the rocker arm 33 is pressed becomes longer, and the valve opening period of the intake bubble 28 becomes longer.
[0022]
On the other hand, as shown in FIG. 4, in the low lift mode in which the valve lift amount of the intake valve 28 is reduced, the initial rotation between the pressing cam 39 of the link arm 34 and the roller 40 of the rocker arm 33 by the rotation of the control shaft 35. Move the contact point position to the left. As a result, when the pressing cam 39 moves to the left and right due to the rotation of the cam 37, the section of the lower end surface of the pressing cam 39 that contacts the roller 40 moves to the left, so that the maximum pressing amount of the rocker arm 33 is reduced. Accordingly, the maximum valve lift amount of the intake valve 28 is reduced, the period during which the rocker arm 33 is pressed is shortened, and the valve opening period of the intake bubble 28 is shortened.
[0023]
In the variable valve lift mechanism 30 described above, if the control shaft 35 is rotated by the stepping motor and the initial contact point position between the pressing cam 39 of the link arm 34 and the roller 40 of the rocker arm 33 is continuously moved, As shown in FIG. 5, the maximum valve lift amount and the valve opening period of the intake valve 28 can be continuously varied.
[0024]
The ECU 27 executes a variable valve lift control program (not shown) stored in the ROM, so that the variable valve lift mechanisms 30 and 31 of the intake valve 28 and the exhaust valve 29 are based on the accelerator opening, the engine operating state, and the like. , And functions as variable valve control means for continuously varying the valve lift amounts of the intake valve 28 and the exhaust valve 29 to control the intake air amount. In the case of a system using both the variable valve lift mechanisms 30 and 13 and the variable valve timing mechanism, the intake air amount may be controlled by continuously varying both the valve lift amount and the valve timing.
[0025]
Further, the ECU 27 executes an automatic stop control program (not shown) stored in the ROM to automatically stop the engine 11 when a predetermined automatic stop condition is satisfied during engine operation.
[0026]
At that time, the ECU 27 executes the automatic start control program of FIG. 6 stored in the ROM, and when a predetermined automatic start condition is established during the automatic stop of the engine 11, as shown in the time chart of FIG. The engine 11 is automatically started. Then, until the elapsed time after the completion of the engine automatic start exceeds the variable valve control prohibition time KCAST, the valve lift amounts of the intake valve 28 and the exhaust valve 29 are fixed to the target valve lift amount at the time of automatic engine start. The control of the intake air amount by the control is prohibited, and during that period, the opening amount of the throttle valve 15 is controlled to control the intake air amount.
[0027]
Hereinafter, the processing content of the automatic start control program of FIG. 6 executed by the ECU 27 will be described.
The automatic start control program of FIG. 6 is repeatedly executed at a predetermined cycle while the engine 11 is automatically stopped. When the program is started, first, at step 101, it is determined whether or not an automatic start condition is satisfied. Here, in the case of a manual transmission vehicle (MT vehicle), the automatic start condition is to satisfy all of the following conditions (1) to (3), for example.
[0028]
(1) The vehicle speed is 0 km / h, that is, the vehicle is stopped. (2) The clutch pedal is depressed. (3) The brake pedal is not depressed. All the above conditions (1) to (3) are satisfied. If the condition is satisfied, the automatic start condition is satisfied. However, if any one of the conditions (1) to (3) is not satisfied, the automatic start condition is not satisfied.
[0029]
In addition, the automatic start condition may be changed as appropriate. In the case of a vehicle equipped with an automatic transmission (AT vehicle), for example, when the shift lever is shifted to the drive range or the like while the brake pedal is depressed, An automatic start condition may be satisfied. In short, in both the AT and MT cars, the automatic start condition may be satisfied when it becomes possible to determine that the driver has performed any operation for starting the vehicle. .
[0030]
When the automatic start condition is satisfied during the automatic engine stop, it is determined that there is an engine start request, and the routine proceeds to step 102, where the target valve lift amount at the automatic engine start of the intake valve 28 and the exhaust valve 29 is calculated. The target valve lift amount at the time of automatic engine start may be a fixed value set in advance for simplification of calculation processing. However, the operating conditions at the time of automatic start (for example, cooling water temperature, oil temperature, intake air temperature, outside air temperature) The engine stop time or the like may be set by a map or a mathematical expression.
[0031]
Thereafter, the routine proceeds to step 103, where variable valve lift control is executed, and the intake valve 28 and the exhaust valve 29 are exhausted so that the valve lift amounts of the intake valve 28 and the exhaust valve 29 become the target valve lift amounts at the time of automatic engine start, respectively. The variable valve lift mechanisms 30 and 31 of the valve 29 are controlled.
[0032]
Thereafter, the routine proceeds to step 104, where it is determined whether or not the valve lift amounts of the intake valve 28 and the exhaust valve 29 are the target valve lift amounts at the time of automatic engine start, and the valve lifts of the intake valve 28 and the exhaust valve 29 are determined. When both the amounts become the target valve lift amount at the time of automatic engine start, the routine proceeds to step 105, where automatic start control is executed, the starter (not shown) is turned on, and the engine 11 is automatically started. The processing in step 105 serves as automatic start control means in the claims.
[0033]
Thereafter, the routine proceeds to step 106, and after the completion of the automatic engine start, the valve lift amounts of the intake valve 28 and the exhaust valve 29 are fixed at the target valve lift amount at the time of the automatic engine start, and the intake air amount by the variable valve lift control is fixed. While prohibiting the control, the throttle control is started, and the opening degree of the throttle valve 15 is controlled to control the intake air amount.
[0034]
Thereafter, the routine proceeds to step 107, where it is determined whether or not the elapsed time CAST after completion of the engine automatic start exceeds the variable valve control inhibition time KCAST. The variable valve control prohibition time KCAST is set to a time required until the operation state is stabilized to some extent after a period including a complex and highly varied transient immediately after the completion of the automatic start from the completion of the automatic start of the engine. . In this case, the variable valve control prohibition time KCAST may be a fixed value set in advance for simplification of calculation processing, but after searching for a map of the variable valve control prohibition time KCAST shown in FIG. The variable valve control inhibition time KCAST may be set according to the number of automatic engine stops (or the number of automatic start).
[0035]
Since the frequency of adverse effects such as drivability due to variable valve lift control and deterioration of exhaust emission increases as the number of engine automatic stops (or the number of automatic starts) after the start of traveling increases, the map in FIG. The variable valve control inhibition time KCAST becomes longer as (or the number of times of automatic start) increases, and the adverse effect due to the variable valve lift control can be reduced. In the example of the map of FIG. 7, when the number of engine automatic stops (or the number of automatic starts) is a predetermined number A or less, the variable valve control inhibition time KCAST is constant at the lower limit value, and the number of engine automatic stops (or automatic start) In the region where the number of times) is equal to or greater than the predetermined number B, the variable valve control inhibition time KCAST is constant at the upper limit value.
[0036]
If it is determined in step 107 that the elapsed time CAST after the completion of the automatic engine start does not exceed the variable valve control prohibition time KCAST, the process returns to step 106 and the intake valve 28 and the intake valve 28 until the variable valve control prohibition time KCAST is exceeded. The valve lift amount of the exhaust valve 29 is fixed to the target valve lift amount at the time of automatic engine start, the intake air amount control by the variable valve lift control is prohibited, and the opening degree of the throttle valve 15 is controlled to control the intake air amount. Continue processing. The processing of these steps 106 and 107 serves as variable valve control prohibiting means and throttle control means in the claims.
[0037]
Thereafter, when it is determined in step 107 that the elapsed time CAST after the completion of the automatic engine start has exceeded the variable valve control inhibition time KCAST, the routine proceeds to step 108 where the variable valve lift control is permitted and the throttle control is terminated. Thus, after the variable valve control prohibition time KCAST has elapsed since the completion of the engine automatic start, the valve lift amounts of the intake valve 28 and the exhaust valve 29 are continuously varied based on the accelerator opening, the engine operating state, and the like. Control intake air volume. While the intake air amount control by the variable valve lift control is being executed, the throttle valve 15 is fixed at, for example, the fully open position to reduce the intake resistance.
[0038]
In the case of a system using both the variable valve lift mechanisms 30 and 31 and the variable valve timing mechanism, the valve lift amount and the valve timing are respectively set until the variable valve control prohibition time KCAST elapses after the engine automatic start is completed. The target valve lift amount at the time of automatic engine start and the target valve timing at the time of automatic engine start may be fixed.
[0039]
In the present embodiment described above, the intake air amount control by the variable valve lift control is performed by fixing the valve lift amounts of the intake valve 28 and the exhaust valve 29 until the variable valve control prohibition time KCAST elapses after the engine automatic start is completed. Since the intake air amount is controlled by prohibiting and controlling the opening of the throttle valve 15, the intake air amount control is performed by the conventional system in a period including a complex and large variation immediately after the engine is automatically started. As a result, the intake air amount can be stably controlled by the proven throttle valve control, and drivability after exhausting the engine automatically and deterioration of exhaust emission can be prevented.
[0040]
Furthermore, in the present embodiment, after the engine automatic start is completed, the valve lift amounts of the intake valve 28 and the exhaust valve 29 are fixed to the target valve lift amount at the time of engine automatic start (before completion of automatic start). Before and after the completion of the automatic start, the valve lift amount can be kept constant to eliminate the change in the valve lift amount, and the torque shock and the exhaust emission deterioration due to the change in the valve lift amount can be prevented.
[0041]
The valve lift amount to be fixed after the engine automatic start is not necessarily limited to the target valve lift amount at the time of the engine automatic start, and the valve lift amount to be fixed after the engine automatic start is set to a preset fixed value, Or you may make it set with a map or a numerical formula etc. according to the driving | running conditions (cooling water temperature, oil temperature, intake air temperature, external temperature, engine automatic stop time etc.) at the time of engine automatic start.
[0042]
Further, in the present embodiment, the variable valve control prohibition time KCAST becomes longer as the engine automatic stop count (or automatic start count) increases, so the engine automatic stop count (automatic start count) after the start of traveling is small, When the frequency of adverse effects such as drivability and exhaust emission deterioration due to variable valve lift control is low, the variable valve control prohibit time KCAST is shortened, and variable valve lift control is started early after the automatic engine start. It is possible to prioritize performance improvement such as fuel efficiency improvement by valve lift control. When the number of automatic engine stops after the start of travel (the number of automatic start) increases and the frequency of adverse effects due to variable valve lift control increases, the variable valve control inhibition time KCAST is lengthened to increase the variable valve The prevention of adverse effects by the variable valve lift control can be prioritized over the performance improvement by the lift control.
[0043]
In this embodiment, the stepping motor is used as the drive source of the variable valve lift mechanisms 30 and 31, but other electromagnetic actuators or hydraulic actuators may be used. Alternatively, the valve opening / closing operation conditions (valve lift amount, valve timing, etc.) may be varied by directly driving the intake valve (exhaust valve) with an electromagnetic actuator.
[0044]
In this embodiment, the present invention is applied to a system that varies the valve opening / closing operation conditions of both the intake valve and the exhaust valve. However, the present invention is applied to a system that varies the valve opening / closing operation conditions of only the intake valve. May be.
[0045]
Further, the present invention is not limited to a vehicle that travels only with the driving force of the engine as long as the vehicle is equipped with an engine automatic stop / start device, and the driving force of the engine and a driving force other than the engine such as a motor are used in combination. You may apply to a hybrid car.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an entire engine control system showing an embodiment of the present invention. FIG. 2 is a front view of a variable valve lift mechanism. FIG. 3 is a diagram for explaining an operation of the variable valve lift mechanism in a high lift mode. FIG. 4 is a diagram for explaining the operation of the variable valve lift mechanism in the low lift mode. FIG. 5 is a valve lift characteristic diagram for explaining the continuously variable operation of the valve lift amount by the variable valve lift mechanism. 6 is a flowchart showing the flow of processing of an automatic start control program. FIG. 7 is a diagram showing an example of a map that defines the relationship between the number of automatic engine stops and variable valve control inhibition time. FIG. 8 is an example of execution of this embodiment. Time chart shown 【Explanation of symbols】
DESCRIPTION OF SYMBOLS 11 ... Engine (internal combustion engine), 15 ... Throttle valve, 20 ... Fuel injection valve, 21 ... Spark plug, 26 ..., 27 ... ECU (variable valve control means, automatic start control means, variable valve control prohibition means, throttle control means , 28 ... Intake valve, 29 ... Exhaust valve, 30, 31 ... Variable valve lift mechanism, 32 ... Cam shaft, 33 ... Rocker arm, 34 ... Link arm, 35 ... Control shaft, 36 ... Eccentric cam, 37 ... Cam.

Claims (4)

An air flow meter provided in an intake passage of the internal combustion engine for detecting an intake air amount;
A throttle valve provided downstream of the air flow meter in the intake passage;
Variable valve control means for controlling at least the intake air amount by varying the valve opening / closing operation conditions of both intake valves and intake / exhaust valves of the internal combustion engine;
In a control device for an internal combustion engine comprising automatic start control means for automatically starting the internal combustion engine when a predetermined automatic start condition is satisfied during automatic stop of the internal combustion engine,
Both the intake valve and the intake and exhaust valves during a predetermined period (hereinafter referred to as “variable valve control prohibition period”) until the rotational speed of the internal combustion engine reaches a stable state after the internal combustion engine is automatically started by the automatic start control means. Variable valve control prohibiting means for fixing the valve opening / closing operation condition to a predetermined condition;
The opening degree of the throttle valve located between the air flow meter and the intake valve is controlled with the valve opening / closing operation conditions of both the intake valve and the intake / exhaust valve fixed to predetermined conditions during the variable valve control prohibition period. And a throttle control means for controlling the intake air amount.   2. The internal combustion engine according to claim 1, wherein the variable valve control prohibiting unit fixes the valve opening / closing operation condition to a target valve opening / closing operation condition when the internal combustion engine is automatically started during the variable valve control prohibiting period. Control device.   The control apparatus for an internal combustion engine according to claim 1 or 2, wherein the variable valve control prohibiting means sets the variable valve control prohibition period according to the number of automatic stop or automatic start of the internal combustion engine. Variable valve control means for controlling at least the intake air amount by varying the valve opening / closing operation conditions of both intake valves and intake / exhaust valves of the internal combustion engine;
In a control device for an internal combustion engine comprising automatic start control means for automatically starting the internal combustion engine when a predetermined automatic start condition is satisfied during automatic stop of the internal combustion engine,
Variable valve control prohibiting means for fixing the valve opening / closing operation condition to a predetermined condition during a predetermined period after the internal combustion engine is automatically started by the automatic start control means (hereinafter referred to as “variable valve control prohibition period”);
Throttle control means for controlling the amount of intake air by controlling the opening of a throttle valve provided in the intake passage of the internal combustion engine during the variable valve control prohibition period;
The control apparatus for an internal combustion engine, wherein the variable valve control prohibiting means sets the variable valve control prohibition period according to the number of automatic stop or automatic start of the internal combustion engine.

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