JP2005315130A - Intake control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve acceleration time torque responsiveness restricted by responsiveness of variable valve systems. <P>SOLUTION: A target load tQH0 is calculated from accelerator opening APO and an engine speed Ne. A target angle tVEL of a lift operating angle of the first variable valve system and a target angle tVTC of a central angle of the second variable valve system are determined in response to this target load. In acceleration when the engine speed Ne is a predetermined engine speed cNe or more and a deviation errVTC of the central angle is a reference deviation cerrVTC2 or more, a correction quantity hosQH0 is added to the target load tQH0, and is set as a transition time target load tQH0d. The target load tQH0 is used as it is at steady time. Since a negative pressure control valve target opening arithmetic operation part 43 calculates negative pressure control valve target opening tBCV by using the transition time target load tQH0d, opening becomes larger than the steady time, and suction negative pressure reduces. Thus, actual torque is highly provided, and the torque responsiveness is improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an intake air control device that controls an intake air amount sucked into a cylinder of an internal combustion engine, and more particularly to an internal combustion engine that achieves control of an intake air amount by variable control of valve lift characteristics of an intake valve. The present invention relates to an intake control device.

  In a gasoline engine, the intake air amount is generally controlled by controlling the opening of a throttle valve provided in the intake passage. As is well known, this type of system has a particularly small throttle valve opening. There is a problem that the pumping loss is large at low load. On the other hand, attempts have been made to control the intake air amount without depending on the throttle valve by changing the opening / closing timing of the intake valve and the lift amount. Similarly, it has been proposed to realize a so-called throttle-less configuration in which the intake system is not equipped with a throttle valve.

  Patent Document 1 discloses a variable valve mechanism that can be continuously variably controlled by a lift amount and an operating angle of an intake valve and a central angle of the lift previously proposed by the present applicant. According to this type of variable valve mechanism, as described above, it is possible to variably control the amount of air flowing into the cylinder without depending on the opening degree control of the throttle valve, particularly in a region where the load is small. In other words, so-called throttleless operation or operation with a sufficiently large opening of the throttle valve can be realized, and the pumping loss can be greatly reduced.

  Here, when the intake air amount is controlled by variable control of the valve lift characteristic of the intake valve as in Patent Document 1, the complete throttle-less configuration without the throttle valve has a negative effect on the intake system. Because no pressure is generated, for example, existing systems that recirculate blow-by gas or purge gas from an evaporator to the intake system cannot be used, or negative pressure that is also used as a drive source for various actuators can be easily obtained. New issues such as inability to derive.

For this reason, a negative pressure control valve similar to a so-called electronically controlled throttle valve is provided, and combined with its opening control, the intake air amount is controlled by the valve lift characteristic of the intake valve while ensuring a substantially constant negative pressure. The present applicant is examining this (Patent Document 2).
JP 2001-263105 A JP 2002-256905 A

  However, in the configuration in which the operating angle and the central angle of the intake valve are variably controlled independently of each other according to the engine operating state as described above, two variable valve mechanisms are used during a transient state in which the operating state changes suddenly. Each of which operates with a certain delay relative to the target value, and the respective operation delays can occur at the same time, the intake air amount may deviate from the target value, and the torque responsiveness particularly during acceleration may deteriorate. is there.

  An intake control apparatus for an internal combustion engine according to the present invention includes a first variable valve mechanism that can continuously change the operating angle of the intake valve of the internal combustion engine, and a second variable valve that can continuously change the central angle of the operating angle. A variable valve mechanism; and a negative pressure control valve provided in the intake passage of the internal combustion engine for controlling the intake negative pressure. In addition, an intake valve control means for controlling the first variable valve mechanism and the second variable valve mechanism according to the operating state is provided. That is, the operating angle and the central angle of the intake valve are controlled so that a target air amount can be obtained under a desired intake negative pressure.

  And a target load calculating means for calculating a target load according to the accelerator opening and the engine speed, and a negative pressure control for setting a negative pressure control valve target opening according to the engine speed and the target load. A target valve opening setting unit; an acceleration determination unit that determines whether the current operating state is an acceleration that satisfies a predetermined condition; and when the acceleration determination unit determines a predetermined acceleration, the negative pressure control valve target Negative pressure control valve target opening correction means for correcting the opening larger than the negative pressure control valve target opening at the time of steady state in which the rotational speed and load are equal to the current operating state. Therefore, at the time of acceleration satisfying a predetermined condition, the opening degree of the negative pressure control valve is corrected so as to be larger than that at the normal time, and the suction negative pressure is reduced (that is, approaches the atmospheric pressure), so that the torque response is improved. .

  As the correction of the negative pressure control valve target opening, the negative pressure control valve target opening setting means may finally correct the value set according to the rotation speed and the target load, which will be described later. As in the embodiment, the correction of the target opening of the negative pressure control valve can be realized by correcting the target load that is input to the negative pressure control valve target opening setting means.

  One of the determination conditions in the acceleration determination means can include that the rotational speed of the internal combustion engine is equal to or greater than a predetermined value. That is, no correction is made at low rotations with high use frequency, and torque response at high rotations is improved.

  One of the determination conditions in the acceleration determination means may include that the target operating angle of the second variable valve mechanism is a predetermined value or less. Since the operating angle is basically large on the high load side, correction is performed only when the load is high, and correction is not performed when the load is frequently used and the torque response is improved only when the load is high.

  One of the determination conditions in the acceleration determination means may include that the difference between the target operating angle and the actual operating angle of the second variable valve mechanism is a predetermined value or more. The above difference indicates whether acceleration is rapid or slow. Therefore, the correction is not performed when the acceleration request is frequently used and the torque response is improved only when the acceleration request is abrupt.

  Further, as the correction in the negative pressure control valve target opening correction means, the correction amount may be changed according to the rotational speed of the internal combustion engine. As a result, the correction amount can be set according to the speed of development of the negative pressure.

  Alternatively, the correction amount may be changed according to the target operating angle or the actual operating angle of the second variable valve mechanism. That is, the correction amount can be set according to the current required load or actual load.

  Furthermore, the correction amount may be changed according to the difference between the target operating angle and the actual operating angle of the second variable valve mechanism. That is, the correction amount can be set according to the current acceleration request.

  According to the present invention, during acceleration that satisfies a predetermined condition, the opening degree of the negative pressure control valve is made larger than that in the steady state and the suction negative pressure is reduced, so that the torque response can be improved.

  FIG. 1 is a configuration explanatory view showing the system configuration of an intake control device for an internal combustion engine according to the present invention. The internal combustion engine 1 has an intake valve 3 and an exhaust valve 4, and the valve of the intake valve 3 is operated. As a mechanism, the first variable valve mechanism (VEL) 5 capable of continuously expanding / reducing the lift / operation angle of the intake valve 3 and the center angle of the operation angle can be continuously delayed. A second variable valve mechanism (VTC) 6 is provided. The intake passage 7 is provided with a negative pressure control valve 2 whose opening degree is controlled by an actuator such as a motor. Here, the negative pressure control valve 2 is used to generate a slight negative pressure (for example, −50 mmHg) necessary for blowby gas processing or the like in the intake passage 7. The adjustment is basically performed by changing the lift characteristics of the intake valve 3 by the first and second variable valve mechanisms 5 and 6.

  More specifically, in the low load side region (first region), the opening degree (target opening degree tBCV) of the negative pressure control valve 2 is controlled so that the suction negative pressure is constant (for example, −50 mmHg). And in the high load side region (second region) where the required load exceeds the maximum load that can be realized by changing the lift characteristic while generating this constant negative pressure, it is fixed to the lift characteristic at the point that becomes the limit, As the load, for example, the accelerator opening APO increases, the opening of the negative pressure control valve 2 further increases. That is, the intake air amount is adjusted by changing the lift characteristic of the intake valve 3 while maintaining a relatively weak intake negative pressure up to a certain load, and in the high load side region close to the fully open region, the intake negative pressure is adjusted. The amount of intake air is adjusted by reducing.

  The first and second variable valve mechanisms 5 and 6 and the negative pressure control valve 2 are controlled by the control unit 10.

  A fuel injection valve 8 is disposed in the intake passage 7, and an amount of fuel corresponding to the intake air amount adjusted by the intake valve 3 or the negative pressure control valve 2 as described above is supplied from the fuel injection valve 8. Be injected. Accordingly, the output of the internal combustion engine 1 is controlled by adjusting the intake air amount by the first and second variable valve mechanisms 5 and 6 in the first region, and the negative pressure control valve 2 in the second region. Is controlled by adjusting the intake air amount.

  The control unit 10 includes an accelerator opening signal APO from an accelerator angle sensor 11 provided on an accelerator pedal operated by a driver, an engine speed signal Ne from an engine speed sensor 12, and an intake air amount sensor. 13 is received, and based on these signals, the fuel injection amount, the ignition timing, the negative pressure control valve target opening, the first variable valve mechanism target angle (operating angle target value), the first 2 The variable valve mechanism target angle (center angle target value) is calculated. The fuel injection valve 8 and the spark plug 9 are controlled so as to realize the required fuel injection amount and ignition timing, and the negative pressure control valve target opening, the first variable valve mechanism target angle, and the second variable valve are controlled. Control signals for realizing the mechanism target angle are output to the actuator of the negative pressure control valve 2, the actuator of the first variable valve mechanism 5, and the actuator of the second variable valve mechanism 6, respectively. The first variable valve mechanism 5 and the second variable valve mechanism 6 have known mechanical configurations, and have, for example, the same configuration as the device described in Patent Document 1 described above. Therefore, the detailed description is abbreviate | omitted.

  FIG. 2 is a schematic flowchart of processing for calculating the first variable valve mechanism target angle tVEL, the second variable valve mechanism target angle tVTC, and the negative pressure control valve target opening degree tBCV in the configuration of the above embodiment. . First, the target load tQH0 is calculated from the accelerator opening APO and the engine speed Ne (step 01), and the second variable valve mechanism target angle tVTC and the first variable valve mechanism are calculated from the target load tQH0 and the engine speed Ne. A target angle tVEL is calculated (steps 02 and 03). Next, a transient target load tQH0d is calculated (step 04), and a negative pressure control valve target opening tBCV including correction during acceleration is calculated using the transient target load tQH0d (step 05).

  FIG. 3 is a flowchart showing a calculation process of the target angle tVTC of the second variable valve mechanism 6 and shows the details of step 02 described above. In this embodiment, the target angle tVTC of the second variable valve mechanism 6 is also corrected at the time of transition. First, based on the target load tQH0 calculated in Step 01 and the engine speed Ne, the second variable valve mechanism steady target angle tVTCs is searched from a predetermined map (Step 11). Next, the actual center angle at that time, that is, the second variable valve mechanism actual angle rVTC is read (step 12), and the second variable valve mechanism deviation amount errVTC is calculated as the difference between the two (step 13). This is compared with the reference deviation amount cerrVTC1 (step 14). If errVTC ≧ cerrVTC1, it is determined that the state is a sudden transition state, and the second variable valve mechanism correction amount chosVTC is added to the second variable valve mechanism steady target angle tVTCs to obtain the second variable valve mechanism target angle. tVTC is calculated (step 15). On the other hand, if errVTC <cerrVTC1 in step 14, it is a steady or moderate transition, so the second variable valve mechanism steady target angle tVTCs is directly used as the second variable valve mechanism target angle tVTC (step 16).

  FIG. 4 is a flowchart showing a calculation process of the target angle tVEL of the first variable valve mechanism 5 and shows details of step 03 described above. In this embodiment, the target angle tVEL of the first variable valve mechanism 5 is also corrected at the time of transition. First, the first variable valve mechanism steady target angle tVELs is searched from a predetermined map based on the target load tQH0 calculated in step 01 and the engine speed Ne (step 21). Next, as in step 14, the second variable valve mechanism deviation amount errVTC at that time and the reference deviation amount cerrVTC1 are compared (step 22), and if errVTC ≧ cerrVTC1, it is determined that there is an abrupt transition. Then, the first variable valve mechanism correction amount hosVEL is calculated by multiplying the second variable valve mechanism deviation amount errVTC by the first variable valve mechanism correction gain gaVEL (step 23), and the first variable valve mechanism correction steady target. A first variable valve mechanism target angle tVEL is calculated by adding the first variable valve mechanism correction amount hosVEL to the angle tVELs (step 24). On the other hand, if errVTC <cerrVTC1 in step 23, it is a steady or moderate transition, so the first variable valve mechanism steady target angle tVELs is used as it is as the first variable valve mechanism target angle tVEL (step 25).

  As described above, by correcting the second variable valve mechanism target opening tVTC and the first variable valve mechanism target opening tVEL at the time of transition, the torque responsiveness at the time of transient is improved. In the invention, it is not necessarily essential.

  FIG. 5 is a functional block diagram showing the contents of the second variable valve mechanism target angle calculation process of FIG. Here, tQH0 is the target load, Ne is the engine speed, and based on these, the second variable valve mechanism steady target angle map mpVTC21 is used to retrieve the second variable valve mechanism steady target angle tVTCs. Calculated. Then, a deviation between the second variable valve mechanism actual angle rVTC and the second variable valve mechanism steady target angle tVTCs is obtained at the addition point 22. If the second variable valve mechanism deviation amount errVTC is determined to be greater than or equal to the reference deviation amount cerrVTC1 at the block 23 during sudden acceleration, the second variable valve mechanism correction unit 24 surrounded by a dotted line makes the second allowable value. A value obtained by correcting the variable valve mechanism steady target angle tVTCs is selected via the block 25 and is output as the second variable valve mechanism target angle tVTC.

  The second variable valve mechanism steady target angle tVTCs is corrected by adding a preset second variable valve mechanism correction amount chosVTC at the addition point 26 to the second variable valve mechanism steady target opening tVTCs. Thus, the second variable valve mechanism target angle tVTC is obtained. If the second variable valve mechanism deviation errVTC is less than the reference deviation cerrVTC1, the second variable valve mechanism steady target opening tVTCs is output as the second variable valve mechanism target angle tVTC without being corrected. .

  Similarly, FIG. 6 shows the contents of the first variable valve mechanism target angle calculation process of FIG. 4 as a functional block diagram. Here, tQH0 is the target load, Ne is the engine speed, and by searching from the first variable valve mechanism steady target angle map mpVEL31 based on these, the first variable valve mechanism steady target angle tVELs is obtained. Calculated. When it is determined in block 32 that the above-described second variable valve mechanism deviation amount errVTC is equal to or greater than the reference deviation amount cerrVTC1, the first variable valve mechanism correction unit 33 surrounded by a dotted line performs the first variable valve operation correction unit 33. A value obtained by correcting the valve mechanism steady target angle tVELs is selected via the block 34 and is output as the first variable valve mechanism target angle tVEL.

  As the correction of the first variable valve mechanism steady target angle tVELs, the first variable valve mechanism correction amount hosVEL is obtained by multiplying the second variable valve mechanism deviation amount errVTC by the first variable valve mechanism correction gain gaVEL in block 35. At the addition point 36, the first variable valve mechanism target angle tVEL is obtained by adding the first variable valve mechanism correction amount hosVEL to the first variable valve mechanism steady target opening degree tVELs. If the second variable valve mechanism deviation errVTC is less than the reference deviation cerrVTC1, the first variable valve mechanism target target angle tVEL is output without correction of the first variable valve mechanism steady target opening tVELs. .

  Next, FIG. 7 is a flowchart showing the flow of correction control, which is the main part of the present invention, and shows details of step 04 described above. In this embodiment, during acceleration in which the engine speed is equal to or greater than a predetermined value and the second variable valve mechanism deviation amount is equal to or greater than a predetermined value, the target load is corrected in a direction to increase to obtain the transient target load. First, the engine speed Ne is compared with the reference engine speed cNe (step 31). If Ne ≧ cNe, the routine proceeds to step 32, where the second variable valve mechanism deviation errVTC is set. It is compared with a predetermined reference deviation amount errVTC2. If errVTC ≧ cerrVTC2 in step 32, the process proceeds to step 33, where the target load correction amount hosQH0 is calculated by multiplying the second variable valve mechanism deviation amount errVTC by the target load correction gain gaQH0. The corrected target load tQH0d0 is calculated by adding the target load correction amount hosQH0 to tQH0.

  On the other hand, if Ne <cNe in step 31 and errVTC <cerrVTC2 in step 32, the process proceeds to step 35, and the target load tQH0 is set as the corrected target load tQH0d0 as it is. Finally, the corrected target load tQH0d0 after step 34 or 35 is compared with a predetermined maximum load maxQH0, whichever is smaller (Select Low), and is output as a transient target load tQH0d (step 36). .

  The reference deviation amount cerrVTC2 may be the same value as the cerrVTC1 described above. In the present embodiment, cerrVTC2> cerrVTC1.

  FIG. 8 is a functional block diagram showing the contents of the correction control of this embodiment. Here, APO is the accelerator opening, and Ne is the engine speed. Based on these values, the target load calculation unit 41 calculates the target load tQH0. Then, the transient target load tQH0d is calculated by the transient target load calculator 42 surrounded by the dotted line, and the negative pressure control valve target opening calculator is calculated based on the transient target load tQH0d and the engine speed Ne. At 43, a negative pressure control valve target opening tBCV is calculated. Further, based on the target load tQH0 and the engine speed Ne, the first variable valve mechanism target angle calculation unit 44 and the second variable valve mechanism target angle calculation unit 45 use the first variable valve mechanism target angle tVEL and Second variable valve mechanism target angle tVTC is calculated. The first variable valve mechanism target angle calculator 44 and the second variable valve mechanism target angle calculator 45 have been described with reference to FIGS. 6 and 5, respectively.

  The correction of the transient target load includes the condition that the engine speed Ne of the block 46 is equal to or higher than a predetermined reference engine speed cNe, and the second variable valve mechanism deviation amount errVTC of the block 47 is a predetermined reference deviation amount. When the AND condition 48 of the condition that it is greater than or equal to cerrVTC2 is satisfied, the corrected value of the target load tQH0 is selected via the block 49. Specifically, in block 50, the target load correction amount hosQH0 is calculated by multiplying the second variable valve mechanism deviation amount errVTC by the target load correction gain gaQH0, and the target load correction amount hosQH0 is added to the target load tQH0 at the addition point 51. Is added to calculate the corrected target load tQH0d0. Then, in the “Select Low” block 52, the smaller one of the corrected target load tQH0d0 and the maximum load QH0 is selected and output as the transient target load tQH0d.

  FIG. 9 is a time chart showing the action at the time of transition (acceleration) according to the above embodiment. This shows the action when the driver performs acceleration traveling in which the engine speed Ne increases as the accelerator pedal depression amount (accelerator opening APO) is increased, and (a) the target load, (B) First variable valve mechanism angle, (c) Second variable valve mechanism angle, (d) Negative pressure control valve opening, (e) Suction negative pressure, (f) Engine torque, (g) Engine rotation It shows the change in number. In addition, the suction negative pressure of (e) is shown in a direction in which the upper side in the drawing is the atmospheric pressure side and the lower side is the vacuum side.

  When the amount of depression of the accelerator opening is increased from time t1 to time t5 during traveling, the target load tQH0 corresponding to the accelerator opening APO is obtained as shown by the line A11 in (a).

  Here, the operation when the target load tQH0 is directly given as a final target value will be described first.

  First, when the first variable valve mechanism target angle and the second variable valve mechanism target angle are not corrected during the transition, the first variable valve mechanism target angle tVEL is expressed by the sign of (b). Like the line indicated by B11, the second variable valve mechanism target angle tVTC is indicated by the reference numeral D11 in (d), and the negative pressure control valve target opening degree tBCV is indicated by the reference numeral D11 in (d). Each is output like a line. Since the actual angle and opening change with a delay from the target value, the lines indicated by the reference numeral B21 in (b), the reference numeral C21 in (c), and the reference numeral D21 in (d), respectively. It becomes a characteristic. As a result, the actual torque of the internal combustion engine has a characteristic as indicated by a line indicated by reference numeral F1 in (f).

  Further, as described above, when the first variable valve mechanism target angle and the second variable valve mechanism target angle are corrected at the time of transition, the second variable valve mechanism deviation amount errVTC is a predetermined reference deviation amount. As a result of correction of each target angle from time t2 to time t7 that is equal to or greater than errVTC1, the first variable valve mechanism target angle tVEL is calculated as shown by the line B12 in FIG. The two variable valve mechanism target angle tVTC is calculated as shown by the line indicated by reference numeral C12 in (c). Since the negative pressure control valve target opening degree tBCV is not corrected, the negative pressure control valve target opening degree tBCV is calculated in the same manner as in the above example, and becomes the characteristic of the symbol D11 in (d). Since each actual angle and opening change with a delay from the target value, as shown by lines B22 in (b), C22 in (c), and D21 in (d), respectively. It becomes a characteristic. As a result, the actual torque of the internal combustion engine has a characteristic as indicated by a line indicated by a symbol F2 in (f).

  In any case, since the negative pressure control valve target opening tBCV remains set along the steady state, the suction negative pressure is stable around a predetermined constant value as indicated by the line E1 in (e). To do.

  On the other hand, in the present embodiment in which the target load tQH0 is corrected to improve the response at the time of transition, from the time t3 to the time t6 when the second variable valve mechanism deviation amount errVTC is equal to or greater than the predetermined reference deviation amount errVTC2. The period overlapped with the period after time t4 when the engine speed Ne indicated by the sign G1 in (g) is equal to or greater than a predetermined reference engine speed cNe (line G0 in (g)), that is, The target load tQH0 is corrected from time t4 to time t6 when both conditions are satisfied simultaneously. Specifically, it is corrected according to the second variable valve mechanism deviation amount errVTC, and the transient target load tQH0d is calculated as indicated by a line indicated by reference numeral A12 in FIG. At this time, the transient target load tQH0d is limited so as not to exceed the maximum load indicated by the symbol A10 in FIG. Since the negative pressure control valve target opening degree tBCV is calculated using this transient target load tQH0d, the characteristic is as indicated by a line indicated by reference numeral D12 in (d). That is, it is given as a larger value than the negative pressure control valve target opening degree tBCV in the steady state. As a result, the suction negative pressure temporarily decreases as indicated by the line E2 in (e), so that the torque of the internal combustion engine can be obtained with the characteristic as indicated by the line indicated by F3 in (f). That is, the torque response is higher than the characteristics of the symbols F1 and F2 when the above-described correction is not performed.

BRIEF DESCRIPTION OF THE DRAWINGS Configuration explanatory drawing which shows the system configuration | structure of the intake control device of the internal combustion engine which concerns on this invention. The flowchart which shows the whole intake control. The flowchart of a 2nd variable valve mechanism target opening degree calculation process. The flowchart of a 1st variable valve mechanism target opening degree calculation process. The functional block diagram which shows a 2nd variable valve mechanism target opening calculation process. The functional block diagram which shows a 1st variable valve mechanism target opening degree calculation process. The flowchart of the target load calculation process at the time of a transition. The functional block diagram which shows the whole intake control. The time chart which shows the correction | amendment at the time of the acceleration by an Example.

Explanation of symbols

2 ... Negative pressure control valve 5 ... First variable valve mechanism 6 ... Second variable valve mechanism 10 ... Control unit 11 ... Accelerator opening sensor

Claims (8)

A first variable valve mechanism capable of continuously changing the operating angle of the intake valve of the internal combustion engine;
A second variable valve mechanism capable of continuously changing the central angle of the operating angle;
A negative pressure control valve provided in the intake passage of the internal combustion engine for controlling the intake negative pressure;
An intake control device for an internal combustion engine comprising:
An intake valve control means for controlling the first variable valve mechanism and the second variable valve mechanism according to an operating state;
A target load calculating means for calculating a target load according to the accelerator opening and the rotational speed of the internal combustion engine;
Negative pressure control valve target opening setting means for setting a negative pressure control valve target opening according to the rotational speed of the internal combustion engine and the target load;
Acceleration determination means for determining whether the current driving state is acceleration satisfying a predetermined condition;
When the acceleration determining means determines that the acceleration is a predetermined acceleration, the negative pressure control valve target opening is corrected to be larger than the steady-state negative pressure control valve target opening at the time when the rotation speed and load are equal to the current operating state. Negative pressure control valve target opening correction means,
An intake control device for an internal combustion engine, comprising:   2. The intake control apparatus for an internal combustion engine according to claim 1, wherein the acceleration determination means includes that the rotational speed of the internal combustion engine is equal to or greater than a predetermined value.   The intake control apparatus for an internal combustion engine according to claim 1 or 2, wherein the acceleration determination means includes, in the above condition, that a target operating angle of the second variable valve mechanism is a predetermined value or less.   The acceleration determination means includes the condition that a difference between a target operating angle and an actual operating angle of the second variable valve mechanism is a predetermined value or more. An intake control device for an internal combustion engine according to claim 1.   The intake control device for an internal combustion engine according to any one of claims 1 to 4, wherein the negative pressure control valve target opening degree correcting means changes a correction amount in accordance with the rotational speed of the internal combustion engine.   6. The negative pressure control valve target opening degree correction means changes a correction amount according to a target operating angle or an actual operating angle of the second variable valve mechanism. An intake control device for an internal combustion engine.   7. The negative pressure control valve target opening correction means changes a correction amount according to a difference between a target operating angle and an actual operating angle of the second variable valve mechanism. An intake control device for an internal combustion engine according to claim 1. The negative pressure control valve target opening correction means realizes correction of the negative pressure control valve target opening by correcting the target load that is input to the negative pressure control valve target opening setting means. An intake control device for an internal combustion engine according to any one of claims 1 to 7.

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