JP4556816B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine that controls idle rotation speed, and more particularly, to control an intake air amount by a variable valve device that can variably control the valve lift characteristics of the intake valve. Relates to the 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 shows a variable valve operating apparatus for an intake valve previously proposed by the present applicant, and a first variable valve mechanism that can simultaneously increase and decrease the lift and operating angle of the intake valve simultaneously ( A lift / operating angle variable mechanism) and a second variable valve mechanism (phase variable mechanism) capable of continuously delaying the central angle of the operating angle, and controlling both independently A technique that can be variably controlled to various lift characteristics is disclosed. According to this type of variable valve mechanism, 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, and so-called throttleless operation, particularly in a small load region. Or, the operation with the throttle valve opening kept sufficiently large can be realized, and the pumping loss can be greatly reduced. In the device of Patent Document 1, the intake air amount is accurately controlled by setting the valve lift amount to a minute amount during idle operation.

  Note that when the intake air amount is controlled by variable control of the valve lift characteristic of the intake valve as in Patent Document 1, if the complete throttle-less configuration without the throttle valve is used, a negative pressure is applied to the intake system. For example, an existing system that recirculates blow-by gas or purge gas from a canister 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. There is a new issue, such as no. Therefore, a so-called electronically controlled throttle valve is provided as a negative pressure control valve in the intake passage, and combined with its opening control, the intake air amount can be controlled by the valve lift characteristics of the intake valve while ensuring a substantially constant negative pressure. It is also considered to do.

For example, in the purge of a canister that uses negative pressure, the required purge amount cannot be secured if there is no suction negative pressure. However, in Patent Document 2, the intake valve opening / closing timing is used to control the intake air amount. By switching between the method for controlling the intake and the method for controlling the opening of the intake throttle valve, it is possible to switch between a state where the suction negative pressure is low and a state where the suction negative pressure is high. Is provided by feedforward control.
JP 2003-74318 A JP 2001-221094 A

  However, an actual actuator in a variable valve mechanism or the like has a response delay and a response speed limit, and there is a time delay until the target value is realized. In addition, this response delay varies greatly depending on the type of actuator. Furthermore, the target value of each actuator required varies depending on the operating conditions of the engine, individual differences, differences in environmental conditions such as atmospheric pressure, and the like.

  Therefore, when the suction negative pressure is switched from a small state to a large state, or when switching from a large state to a small state, the target value setting is simply given by feedforward control according to the switching request, so that the required air amount can be realized. Therefore, the idling speed may be greatly disturbed.

The present invention includes a variable valve mechanism that can continuously change at least one of a lift and an operating angle of an intake valve, a negative pressure control valve that is interposed in an intake passage and that continuously changes in opening degree, and an internal combustion engine An idle determination means for detecting that the engine is in an idle state, and feedback-controls one of the variable valve mechanism and the negative pressure control valve so as to maintain the target rotational speed in the idle state. with the other feed-to-forward control, and depending on the conditions, and a second control state in which the first control state and the suction negative pressure suction negative pressure becomes relatively large, it becomes relatively small the controller of an internal combustion engine switched on, the on switching between the first control state and the second control state, and the current value of the parameter corresponding to the intake air amount, the variable valve mechanism and the negative At least one of the current position of the control valve, based on, and determines either whether the feedback control. For example, the between the first control state, the feedback control of the negative pressure control valve with feedforward controlling the variable valve mechanism, and between said second control state is fed to the negative pressure control valve Forward control and feedback control of the variable valve mechanism, and at the time of switching from the first control state to the second control state, the current position of the variable valve mechanism is the current parameter corresponding to the intake air amount. The negative pressure control valve is feedback controlled until a threshold value corresponding to the value is reached, and the current position of the negative pressure control valve corresponds to the intake air amount when switching from the second control state to the first control state. The variable valve mechanism is feedback controlled until a threshold value corresponding to the current value of the parameter to be reached is reached.

  In other words, by selecting the one with relatively high controllability as the object of feedback control under the control position of the variable valve mechanism or the negative pressure control valve and the intake air amount at that time, the actuator can be operated slightly. A large change in the intake air amount can be obtained. Therefore, at the time of switching between a state where the suction negative pressure is high and a state where the suction negative pressure is low, a change in the intake air amount can be suppressed as much as possible, and a change in the idle rotation speed can be suppressed.

  As the parameter corresponding to the intake air amount, the intake air amount itself can be used, and for example, the current estimated torque of the internal combustion engine can be used.

  According to the present invention, when switching between a state where the suction negative pressure is large and a state where the suction negative pressure is small, for example, for canister purging, the one with relatively high controllability is used. Since feedback control is performed, it is possible to suppress changes in the intake air amount and, in turn, fluctuations in the idle speed.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a configuration explanatory view showing a system configuration of a control device for an internal combustion engine according to the present invention. The internal combustion engine 1 for an automobile has an intake valve 3 and an exhaust valve 4. As the valve operating mechanism, the first variable valve operating mechanism 5 capable of continuously expanding / reducing the lift / operating angle of the intake valve 3 and the central angle of the operating angle can be continuously delayed. A second variable valve mechanism 6 is provided. The intake passage 7 is provided with an electronically controlled throttle valve type 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 provided for the purpose of generating a slight negative pressure (for example, −50 mmHg) necessary for blow-by gas processing in the intake passage 7. The adjustment is basically performed by changing the lift characteristic of the intake valve 3 by the first and second variable valve mechanisms 5 and 6 except in a high load range (second control region) and an idle time described later. Is called. That is, as schematically shown in FIG. 2, in the low to medium load region, the central angle (VTC) is set close to top dead center (set value: large) in order to improve fuel efficiency, and promote internal reflux. The operating angle (VEL) is gradually set to the large operating angle (set value: large) side according to the torque demand. In the first control region, the negative pressure control valve opening BCV is controlled by the normal engine (not the variable valve mechanism but the throttle valve opening so as to keep the intake negative pressure (Boost) at a predetermined value. Compared to the characteristics of the thing (shown as Std-Eng in the figure), it becomes a characteristic with an open feeling. In the middle to high load range, in order to secure torque, the center angle is set close to bottom dead center (setting value: small), internal recirculation is reduced, and the operating angle is set to the large operating angle (setting value: large) side. And constant. When reaching the second control region, that is, the high load region where the air amount does not increase due to the operation of the valve lift characteristic, the valve lift characteristic is fixed in that state, and the negative intake pressure (Boost) is reduced to generate torque. The negative pressure control valve opening BCV opens as in the normal engine.

  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 like as described above is injected from the fuel injection valve 8. Therefore, 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 and the negative pressure control valve 2.

  The control unit 10 includes an accelerator opening signal APO from an accelerator opening sensor 11 provided on an accelerator pedal operated by a driver, a rotation speed signal Ne from an engine rotation speed sensor 12, and an intake air amount sensor. 13 is received, and based on these signals, the target throttle valve opening, fuel injection amount, ignition timing, operating angle target value, and central angle target value are calculated. Then, 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 control signals for realizing the operation angle target value and the center angle target value are sent to the first variable motion. Outputs to the actuator of the valve mechanism 5 and the actuator of the second variable valve mechanism 6, respectively, and controls the opening of the negative pressure control valve 2. 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.

  The target opening of the negative pressure control valve 2 and the target values of the first and second variable valve mechanisms 5 and 6 are all based on a map in which corresponding values are assigned using the accelerator opening APO and the rotational speed Ne as parameters. Desired. FIG. 3 shows an example of a BCV map in which the target opening degree of the negative pressure control valve 2 is set. FIG. 4 shows an example of a target operating angle map in which the target value of the first variable valve mechanism 5 is set. 5 shows an example of a target center angle map in which the target value of the second variable valve mechanism 6 is determined.

  Next, FIG. 6 shows the contents of intake air amount control (including idle rotation speed control) by the control unit 10 as a functional block diagram, which will be described below.

  The idle state determination unit B1 in the figure determines whether or not the vehicle is in the idle state based on the accelerator opening APO, the engine rotational speed Ne, and the vehicle speed. For example, as shown in the flowchart of FIG. 7, the accelerator opening APO is not more than a predetermined value (step 1), the rotational speed Ne is within a predetermined upper limit and lower limit (step 2), and the vehicle speed is not more than a predetermined value (step 2). When the three conditions of step 3) are satisfied, it is determined as idle (step 4). Otherwise, it is determined as non-idle (step 5).

The non-thro-throttling switching request determination unit B2 determines whether or not there is a request for switching between the first control state in which the suction negative pressure is large and the second control state in which the suction negative pressure is small. “Throttling” corresponds to the first control state, which means a state where the opening of the negative pressure control valve 2 is small, that is, a state where the suction negative pressure is large, and “non-thro (abbreviation of non-throttling)” This corresponds to the second control state and means a state where the opening degree of the negative pressure control valve 2 is large, that is, a state where the suction negative pressure is small. In this embodiment, for example, it is assumed that there is a request to be in the “throttling” state when the canister needs to be purged. The output of the air-fuel ratio sensor (not shown), the air-fuel ratio correction coefficient in the fuel injection control, The opening of the purge valve in the canister (not shown) is input, and based on this, the presence / absence of a switching request is determined. For example, as shown in the flowchart of FIG. 8, the air-fuel ratio feedback control (λ control) is being performed (step 1), the canister is being purged (step 2), and the air-fuel ratio correction coefficient is not more than a predetermined value. When the three conditions (Step 3) are satisfied, it is determined that there is a request to be in the “throttling” state (Step 4). Otherwise, there is no request (Step 5). judge. As is well known, the air-fuel ratio correction coefficient indirectly indicates the purge gas concentration. If the purge gas concentration is estimated by other control, the result may be used.

  The non-thro-throttling switching determination unit B3 determines whether to actually perform switching in response to the switching request. As shown in the flowchart of FIG. 9, in the idle state (step 1), there is a throttling request (step 2), and the center angle VTC by the second variable valve mechanism 6 is within a predetermined range (step 3). In addition, “throttling”, that is, reduction of the opening of the negative pressure control valve 2 is permitted, and otherwise “throttling” is not permitted.

  The feedback (abbreviated as F / B in the figure) target determination unit B4 determines which of the negative pressure control valve 2 and the first variable valve mechanism 5 is the target of feedback control, and is a throttling device. Existence of demand, intake air amount and VEL actual value (current value of lift / operating angle by first variable valve mechanism 5 or current position of actuator) or actual value of negative pressure control valve 2 opening (negative pressure control valve) The target of feedback control is determined using a predetermined relationship with the current value of the two openings or the current position of the actuator.

  FIG. 10 is a flowchart showing an example of the process. First, in step 1, it is determined whether or not the non-throttling request remains, and if YES, the process proceeds to step 2. In step 2, it is determined whether or not the current feedback control target is the first variable valve mechanism 5. Basically, in the “non-throttling” state, the negative pressure control valve 2 opening is increased by feedforward control, and the idling rotational speed control is realized by feedback controlling the first variable valve mechanism 5 side, On the other hand, in the “throttling” state, the first variable valve mechanism 5 is maintained at a relatively higher lift / operating angle than that in “non-throttling” by feedforward control, and the negative pressure control valve 2 side is feedback-controlled. By doing so, idle rotation speed control is realized. Therefore, if “YES” in the step 2, it is determined that the switching from the “throttling” state to the “non-throttling” state is not being performed, and the process proceeds to the step 3 to set the feedback control target on the first variable valve mechanism 5 side. The routine is terminated. If “NO” in the step 2, it is determined that the “throttling” state is being switched to the “non-throttling” state, and the process proceeds to the step 4.

  In step 4, feedback control is performed based on the relationship between the preset intake air amount, the negative pressure control valve 2 opening degree, and the lift / operating angle (VEL) of the first variable valve mechanism 5 as shown in FIG. Decide whether to target. The “equal Q line” in FIG. 11 indicates a combination of the negative pressure control valve 2 opening degree and the lift / operating angle (VEL) at which the intake air amount becomes a certain value Q. That is, there are innumerable combinations of the negative pressure control valve 2 opening and the lift / operating angle (VEL) at which the intake air amount becomes a certain value Q, and the negative pressure control valve 2 opening is large as shown in the figure. Under conditions, the lift / operating angle at which a constant intake air amount Q is obtained is small, and under conditions where the lift / operating angle is large, the opening of the negative pressure control valve 2 at which a constant intake air amount Q is obtained is small. Here, in step 4, the actual lift / operating angle value (VEL) at that time is compared with the threshold value A in FIG. 11, and if it is larger than the threshold value A, the initial state of switching to the “non-throttling” state. The process proceeds to step 6 to select the negative pressure control valve (abbreviated as BCV in the figure) 2 as the target of feedback control, and this routine is terminated. At this time, the first variable valve mechanism 5 is provided with a value (relatively small lift / operation angle value) suitable for the “non-throttling” state as a target value by feedforward control. The lift / operating angle (VEL) of the valve gradually decreases. If the actual lift / operating angle value (VEL) is less than or equal to the threshold value A in step 4, the process proceeds to step 3, the first variable valve mechanism 5 is selected as the target of feedback control, and this routine is terminated. That is, after switching to the “non-throttling” state, the negative pressure control valve 2 is feedback-controlled until the actual lift / operating angle (VEL) value decreased by the feedforward control becomes the threshold value A. At this point, the feedback control target is switched from the negative pressure control valve 2 to the first variable valve mechanism 5. At the same time, the negative pressure control valve 2 is given a target value (relatively large opening) suitable for the “non-throttling” state by feedforward control.

  On the other hand, if NO in step 1, the process proceeds to step 5 to determine whether or not the current feedback control target is the negative pressure control valve 2. If “YES” in the step 5, it is determined that the switching from the “non-throttling” state to the “throttling” state is not being performed, and the process proceeds to the step 6 to maintain the feedback control target on the negative pressure control valve 2 side. Then, this routine is finished. If “NO” in the step 5, it is determined that the “non-throttling” state is being switched to the “throttling” state, and the process proceeds to the step 7.

  Step 7 is similar to Step 4 described above, and the intake air amount, the negative pressure control valve 2 opening degree, and the lift / operating angle (VEL) of the first variable valve mechanism 5 as shown in FIG. It is determined which one is subject to feedback control from Here, the actual opening degree of the negative pressure control valve 2 at that time is compared with the threshold value B of FIG. 11, and if it is larger than the threshold value B, it is determined as the initial state of switching to the “throttling” state. Proceeding to Step 3, the first variable valve mechanism 5 is selected as a target for feedback control, and this routine is terminated. At this time, a value (relatively small opening) suitable for the “throttling” state is given as a target value to the negative pressure control valve 2 by feedforward control, so that the actual opening gradually increases. Get smaller. If it is determined in step 7 that the actual negative pressure control valve 2 opening is equal to or less than the threshold value B, the process proceeds to step 6 where the negative pressure control valve 2 is selected as a target for feedback control, and this routine is terminated. That is, after switching to the “throttling” state, the first variable valve mechanism 5 is feedback-controlled until the opening of the negative pressure control valve 2 that decreases by feedforward control reaches the threshold value B, and becomes the threshold value B or less. At the time, the target of feedback control is switched from the first variable valve mechanism 5 to the negative pressure control valve 2. At the same time, the first variable valve mechanism 5 is given a target value (relatively large lift / operation angle) suitable for the “throttling” state by feedforward control.

  Here, when FIG. 11 is added, in FIG. 11, only one “equal Q line” is representatively shown, but actually, it can be shown in contour lines for each intake air amount Q. The above thresholds A and B are determined for each intake air amount Q, and therefore can be shown as a boundary line L as a whole. That is, in the region on the lower right side of the boundary line L, the negative pressure control valve 2 is selected as a target for feedback control, and in the region on the upper left side, the first variable valve mechanism 5 is selected as a target for feedback control. The FIG. 12 is an explanatory diagram for explaining the controllability (sensitivity) of the controlled object in each region, and as described above, the opening degree of the negative pressure control valve 2 at which the intake air amount becomes a certain value Q. There are an infinite number of combinations of lift and operating angle (VEL), but in the “throttling” state (especially steady state) where the suction negative pressure is large, it is operated with the characteristics near the region C, and the suction negative pressure is reduced. In the “non-throttling” state (particularly in the steady state), operation is performed with characteristics in the vicinity of the region D. Here, when the intake air amount Q is constant and the opening degree of the negative pressure control valve (BCV) 2 is changed by a certain amount, as shown in the figure, the corresponding change in lift / operating angle (VEL). The width is very large in region C and very small in region D. That is, in the vicinity of the region C, the negative pressure control valve 2 opening degree is relatively higher in control sensitivity than the lift / operating angle (VEL), and therefore, suction is performed by slightly changing the negative pressure control valve 2 opening degree. A large change in the air quantity Q is obtained. Conversely, in the vicinity of the region D, the lift / operating angle (VEL) has a relatively higher control sensitivity than the negative pressure control valve 2, and therefore the intake air amount can be changed by slightly changing the lift / operating angle. A large change in Q is obtained. As described above, the boundary line L in FIG. 11 described above indicates which of the two controlled objects has higher sensitivity.

  In order to avoid the control hunting in the vicinity of the boundary line L, an appropriate hysteresis may be given to the thresholds A and B as shown in FIG. That is, the actual switching lines L1 and L2 to which hysteresis is added are set across the boundary line L determined from the sensitivity (change width) of both, and the switching lines L1 and L2 are crossed in the direction of the arrow. Sometimes, the target of feedback control is switched.

  Next, block B5 in FIG. 6 is a VEL feedback target value calculation unit for obtaining a target value at the time of feedback control of the first variable valve mechanism 5, and block B6 is feedforward control of the first variable valve mechanism 5. VEL feedforward target value calculation unit for obtaining a target value at the time, and based on the determination result of the feedback target determination unit B4 described above, one of the target values is the final lift / operation angle target via the switching unit B7. Selected as value tVEL.

  Similarly, block B8 in FIG. 6 is a BCV feedback target value calculation unit for obtaining a target value at the time of feedback control of the negative pressure control valve 2, and block B9 is a target value at the time of feedforward control of the negative pressure control valve 2. BCV feedforward target value calculation unit for calculating the target value, and any one of the target values is selected as the final opening target value tBCV via the switching unit B10 based on the determination result of the feedback target determination unit B4. .

  FIG. 14 is a flowchart showing the processing of the VEL feedback target value calculation unit B5 and the BCV feedback target value calculation unit B8. First, in step 1, the presence / absence of each feedback control request is determined. If there is, in step 2, each control target value (lift / operating angle target value or negative pressure control valve opening target value) is obtained as a function of the deviation between the current actual rotational speed Ne and the target idle rotational speed. If there is no feedback control request, in step 3, the current lift / operating angle (VEL) or negative pressure control valve 2 opening is maintained as the target value. The target value obtained in step 3 is not actually used (it is not selected by the switching units B7 and B10), but the current value is always set so that the target value does not change suddenly when the next feedback control starts. keeping.

  FIG. 15 is a flowchart showing the processes of the VEL feedforward target value calculation unit B6 and the BCV feedforward target value calculation unit B9, and whether or not there is a request to set the “non-throttling” state in step 1. If YES, each target value suitable for the “non-throttling” state is obtained in step 2. If NO, each target value suitable for the “throttling” state is obtained in step 3. As shown in FIG. 16, target values suitable for the “non-throttling” state are, for example, BCV1 and VEL1, and target values suitable for the “throttling” state are, for example, BCV2 and VEL2. become.

  FIG. 17 is a time chart showing the operation in the embodiment as described above, and during the idle operation, the suction negative pressure is increased for the purge gas treatment as shown in FIG. An example when a request (throttling request) is output is shown. (B) shows the change in lift / operating angle (VEL) together with its control state (whether feedback control or feedforward control), and (c) shows the opening of the negative pressure control valve 2. Is shown together with its control state (whether it is feedback control or feedforward control). During idle operation, basically, the engine is operated in the “non-throttling” state to reduce the pumping loss. Therefore, before the time t1, the lift / operating angle is feedback-controlled as shown in FIG. The control valve opening is feedforward controlled. When a throttling request is issued at time t1, the target value by feedforward control of the negative pressure control valve 2 changes from c1 to c2 in the figure, and after that, the actual negative pressure control valve opening gradually increases. To drop. At this time, the feedback control of the first variable valve mechanism 5 is continued, and the lift / operating angle increases so as to maintain the target idle rotation speed against the increase of the suction negative pressure (the portion indicated by the symbol E). However, as described above, under this condition, the lift / operating angle has a higher sensitivity to the intake air amount. Therefore, the transient increase in the intake air amount due to the response delay of the negative pressure control valve 2 and the idle rotation speed A rise is avoided. At time t2, when the actual negative pressure control valve opening is below the threshold value B described above, the feedback control target is switched to the negative pressure control valve 2 side. At the same time, the target value by feedforward control is given to the first variable valve mechanism 5 as b1, and the actual lift / operating angle changes toward this target value b1.

  The same is true when the non-throttling request is completed at time t3, and the target value of the lift / operating angle changes from b1 to b2 by feedforward control, and the actual lift / operating angle gradually increases after this. Decrease. On the negative pressure control valve 2 side, the feedback control is continued, and the negative pressure control valve opening degree is increased so as to maintain the idling rotational speed against the decrease of the lift / operating angle (the portion indicated by the symbol F). Under this condition, since the sensitivity of the negative pressure control valve opening to the intake air amount is higher, a transient increase in the intake air amount due to a response delay of the first variable valve mechanism 5 and an increase in the idle rotation speed are therefore caused. Avoided. At time t4, when the actual lift / operation angle falls below the threshold A described above, the feedback control target is switched to the first variable valve mechanism 5 side. Simultaneously, the target value by feedforward control is given to the negative pressure control valve 2 as c3.

  FIG. 18 shows, as a reference example, the operation when the target of feedback control is switched simultaneously with the presence or absence of a throttling request. That is, at time t1 when the throttling request is output, the first variable valve mechanism 5 is switched from feedback control to feedforward control, and the negative pressure control valve 2 is switched from feedforward control to feedback control. In this case, as indicated by the symbol G, the negative pressure control valve opening is decreased by feedback control immediately after t1, but at this stage, the influence of the change in the negative pressure control valve opening on the intake air amount is relative. Since the lift / operating angle is dominant, the response delay of the lift / operating angle cannot be offset by feedback control of the negative pressure control valve opening, resulting in a transient increase in intake air volume. As a result, the idle rotation speed increases. The same applies when the throttling request disappears at time t3, the negative pressure control valve opening follows the target value change by feedforward control with delay, and the lift / operating angle becomes feedback control from time t3. However, in the portion indicated by the symbol H, the influence of the change in lift and operating angle on the intake air amount is relatively small, and the negative pressure control valve opening degree is more dominant. As a result, the idle rotation speed increases.

  By the way, the relationship of the boundary line L in FIG. 11 described above is based on the premise that there is no significant difference in the response speeds of the actuators of the negative pressure control valve 2 and the first variable valve mechanism 5 and has been described with reference to FIG. Thus, the magnitude of the change width of the negative pressure control valve opening under the same intake air amount Q (this is the BCV change width) and the change width of the lift / operating angle (this is the VEL change width) From the relationship, if “BCV change width> VEL change width”, the first variable valve mechanism 5 is subject to feedback control, and if “BCV change width ≦ VEL change width”, the negative pressure control valve 2 is feedback controlled. It is targeted.

However, in practice, since the response speed of each actuator differs to some extent, it is more desirable to consider each response speed. That is, the ratio (BCV change speed) of the response speed of the actuator of the negative pressure control valve 2 (this is the BCV change speed) and the response speed of the actuator of the first variable valve mechanism 5 (this is the VEL change speed). / VEL change rate) is multiplied by the VEL change width, and this may be compared with the BCV change width .

Further, the lift / operating angle changes at the position immediately before the cylinder, whereas the negative pressure control valve opening degree changes on the upstream side, so that there is a difference between the air response speeds. Therefore, it is more desirable to consider each air response speed. That is, the ratio (BCV air speed / VEL air speed) of the air response speed of the negative pressure control valve opening (this is referred to as BCV air speed) and the air response speed of the lift / operating angle (this is referred to as VEL air speed). ) Is multiplied by the VEL change width , and this is compared with the BCV change width. In addition, you may make it multiply together the response speed ratio of said actuator.

BRIEF DESCRIPTION OF THE DRAWINGS Configuration explanatory drawing which shows the system configuration | structure of the control apparatus of the internal combustion engine which concerns on this invention. The characteristic view which showed roughly the change of each parameter when the accelerator opening was increased. The characteristic diagram of a BCV map. The characteristic diagram of an operating angle map. The characteristic diagram of a center angle map. The functional block diagram which shows one Example of this invention. The flowchart of idle state determination part B1. 10 is a flowchart of a non-thro-throttling switching request determination unit B2. The flowchart of non-thro-throttling judgment part B3. The flowchart of feedback object determination part B4. The characteristic view which shows the relationship between a negative pressure control valve opening degree, a lift and an operating angle, and intake air amount. The characteristic view similar to FIG. 11 for demonstrating each control sensitivity. The same characteristic view which shows the switching line at the time of giving a hysteresis to a threshold value. The flowchart of feedback target value calculation part B5, B8. The flowchart of feedforward target value calculation part B6, B9. The characteristic view similar to FIG. 11 which shows the example of a feedforward target value. The time chart which shows an example of the effect | action by a present Example. The time chart which shows an example of the effect | action by a reference 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 (3)

A variable valve mechanism that can continuously change at least one of the lift and operating angle of the intake valve, a negative pressure control valve that is interposed in the intake passage and continuously changes in opening degree, and the internal combustion engine is in an idle state And an idle determination means for detecting whether the variable valve mechanism and the negative pressure control valve are feedback-controlled and the other is fed so as to maintain the target rotational speed in the idle state. and forward control, and depending on the condition, the suction negative pressure is relatively large ones become the first control state and the suction negative pressure becomes relatively small second control state and to switch the internal combustion engine In the control device of
At the time of switching between the first control state and the second control state, a current value of a parameter corresponding to the intake air amount, a current position of at least one of the variable valve mechanism and the negative pressure control valve, A control apparatus for an internal combustion engine, which determines which one is to be feedback controlled based on.   2. The control apparatus for an internal combustion engine according to claim 1, wherein a current estimated torque of the internal combustion engine is used as a parameter corresponding to the intake air amount. The variable valve mechanism is feedforward controlled during the first control state and the negative pressure control valve is feedback controlled, and the negative pressure control valve is feedforward controlled during the second control state. And feedback control of the variable valve mechanism,
At the time of switching from the first control state to the second control state, the negative pressure control valve is turned on until the current position of the variable valve mechanism reaches a threshold value corresponding to a current value of a parameter corresponding to the intake air amount. Feedback control,
When switching from the second control state to the first control state, the variable valve mechanism is operated until the current position of the negative pressure control valve reaches a threshold value corresponding to a current value of a parameter corresponding to the intake air amount. 3. The control apparatus for an internal combustion engine according to claim 1 , wherein feedback control is performed .