JP2006112404A - Abnormality determination device of variable valve mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abnormality determination device of a variable valve mechanism capable of easily determining the presence or absence of an abnormality in the variable valve mechanism. <P>SOLUTION: An electronic controller 41 detects the trend of intake air volume while emitting drive instructions to the variable valve mechanism 31 to change the lift time area (for example, maximum lift and operating angle) of an intake valve 21, and based on the results of the detection, determines whether the abnormality is present or absent in the variable valve mechanism 31. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an abnormality determination device for a variable valve mechanism that determines whether there is an abnormality in a variable valve mechanism that varies the lift time area of an intake valve.

  In recent years, a variable valve mechanism in which the maximum lift amount and operating angle of the intake valve, that is, the lift time area of the intake valve (the crank angle integral value of the valve lift amount from valve opening to valve closing) is variable has been put into practical use ( For example, see Patent Document 1). In an internal combustion engine having such a variable valve mechanism, engine performance is further improved by appropriately adjusting the lift time area of the intake valve in accordance with the engine operating state.

The variable valve mechanism described in Patent Literature 1 displaces the mediating member interposed on the power transmission path between the intake valve and the camshaft that drives the valve to open and close, and the mediating member to change the lift time area. And an actuator to be used. The mediating member is individually provided for each cylinder, and the power from the actuator is transmitted to each mediating member via a common movable shaft. The lift time area of each intake valve is changed through the displacement of each intermediary member based on this power transmission.
JP 2001-263015 A

  If an abnormality such as sticking occurs in such a variable valve mechanism and the lift time area command value does not coincide with the actual value, there arises a problem such that a desired intake air amount cannot be obtained. Such an abnormality of the variable valve mechanism can be detected by actually measuring the lift mode of the actual intake valve. However, for that purpose, a special sensor is required, resulting in an increase in cost.

  For example, in the variable valve mechanism described in Patent Document 1, a sensor for detecting the amount of movement of the movable shaft according to the change of the lift time area is provided, and the lift mode of the intake valve is grasped through detection of this amount of movement. I have to. As a result, the number of sensors can be reduced as compared with the case where a sensor for actually measuring the lift mode is provided for each valve.

  However, in this configuration, if the interlinkage between the intermediate member and the movable shaft is damaged, for example, if the correlation between the amount of displacement of the intermediate member and the amount of movement of the movable shaft becomes abnormal, the sensor Thus, the lift mode cannot be accurately grasped, and it is difficult to accurately determine whether there is an abnormality in the variable valve mechanism.

  The present invention has been made in view of such a situation, and a problem to be solved is to provide an abnormality determination device for a variable valve mechanism that can more easily determine whether there is an abnormality in the variable valve mechanism. There is.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
The invention according to claim 1 is an abnormality determination device for a variable valve mechanism that determines whether there is an abnormality in a variable valve mechanism that makes the lift time area of an intake valve of an internal combustion engine variable. The gist is to detect the transition of the intake air amount while issuing a drive command to the variable valve mechanism so as to change the area, and to determine the presence or absence of the abnormality based on the detection result.

  According to this configuration, whether there is an abnormality in the mechanism is determined based on the transition of the intake air amount (actual value) when a drive command is issued to the variable valve mechanism so as to change the lift time area of the intake valve. . Therefore, when performing the above determination, it is not necessary to provide a special sensor for the determination by diverting the detection result by the existing sensor used for detecting the intake air amount.

  Further, since the above determination is made based on the transition of the intake air amount (actual value), the actuator driven to change the lift time area and the intake air as in the configuration described in Patent Document 1, for example. Of the plurality of linked members interposed on the power transmission path to the valve, the above determination can be performed accurately even if an abnormality occurs in the correlation between the members (correlation with respect to the displacement amount, etc.). Will be able to.

  The “lift time area” in the present invention refers to an integral value of the crank angle of the valve lift amount from the valve opening to the valve closing. The change in the lift time area is performed, for example, through a change in the maximum lift amount or the operating angle of the intake valve (either or both of them may be used).

  As an aspect of the determination, for example, according to the invention according to claim 2, in the invention according to claim 1, the presence / absence of the abnormality is determined by changing a command value of the lift time area in the drive command. It is possible to employ a method that is performed based on a comparison between the theoretical change amount and the actual change amount of the intake air amount according to the amount. In this configuration, for example, when the absolute value of the difference between the theoretical change amount and the actual change amount becomes larger than a predetermined value, it is determined that there is an abnormality in the variable valve mechanism.

  As an aspect of the determination, for example, according to the invention of claim 3, in the invention of claim 1, the presence / absence of the abnormality is determined by a command value of the lift time area in the drive command. It is also possible to adopt a method that is performed based on the ratio of the actual change amount of the intake air amount to the change amount. According to this, for example, when the ratio of the actual change amount of the intake air amount to the change amount of the command value of the lift time area in the drive command is out of a predetermined range, it is determined that there is an abnormality in the variable valve mechanism.

  Furthermore, as an aspect of the determination, for example, as in the invention according to claim 4, in the invention according to claim 1, the presence / absence of the abnormality is determined based on a command value of the lift time area in the drive command ( It is also possible to adopt a method that is performed based on a comparison between a theoretical absolute amount of the intake air amount corresponding to the absolute amount) and an actual absolute amount. In the same configuration, for example, when the absolute value of the difference between the theoretical absolute amount and the actual absolute amount becomes larger than a predetermined value, it is determined that there is an abnormality in the variable valve mechanism.

  The invention according to claim 5 is an abnormality determination device for a variable valve mechanism that determines whether there is an abnormality in the variable valve mechanism that makes the lift time area of the intake valve of the internal combustion engine variable, wherein the lift time area of the intake valve is Adjusting the throttle opening based on the change amount of the command value in the drive command so that the intake air amount (actual absolute amount) is kept constant while issuing a drive command to the variable valve mechanism to be changed, The gist is to determine that there is an abnormality when the intake air amount (actual absolute amount) thereafter changes.

  According to this configuration, the throttle opening is adjusted so as to eliminate the change in the intake air amount (actual absolute amount) accompanying the change in the lift time area. For example, when an abnormality occurs in the variable valve mechanism and the lift time area is not changed according to the drive command, the throttle opening is adjusted based on the command value change amount in the drive command. The intake air amount (actual absolute amount) cannot be kept constant, that is, the intake air amount (actual absolute amount) thereafter changes. In the present invention, the presence or absence of abnormality in the variable valve mechanism is determined based on the presence or absence of such a change in the intake air amount (actual absolute amount).

  Thus, in the present invention, the above determination is performed based on the detection result of the intake air amount. Therefore, when performing the above determination, it is not necessary to provide a special sensor for the determination by diverting the detection result by the existing sensor used for detecting the intake air amount.

  In addition, since the above determination is performed based on the detection result of the intake air amount, for example, as in the configuration described in Patent Document 1, an actuator that is driven to change the lift time area and an intake valve It is possible to accurately perform the above determination even if an abnormality occurs in a correlation (correlation with respect to a displacement amount, etc.) between any of a plurality of linked members interposed on the power transmission path between become.

  The “lift time area” in the present invention refers to an integral value of the crank angle of the valve lift amount from the valve opening to the valve closing. The change in the lift time area is performed, for example, through a change in the maximum lift amount or the operating angle of the intake valve (either or both of them may be used).

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, when the intake air amount (actual absolute amount) increases in accordance with the drive command, ignition is performed in accordance with the increase. The gist is to retard the timing.

  According to this configuration, an increase in the output (torque) of the internal combustion engine accompanying an increase in the intake air amount (actual absolute amount) according to the drive command is suppressed. That is, the generation of excessive output during the determination is suppressed.

(First embodiment)
A first embodiment in which the present invention is embodied in an abnormality determination device for a variable valve mechanism in a multi-cylinder internal combustion engine mounted on an automobile will be described below with reference to FIGS.

  As shown in FIG. 1, each combustion chamber (only one place is shown in the figure) 12 of the internal combustion engine 11 receives air through an intake passage 13 and is supplied with fuel from a fuel injection valve 14. When the air-fuel mixture is ignited by the spark plug 15, the air-fuel mixture burns, the piston 16 reciprocates, and the crankshaft 17 that is the engine output shaft rotates. The air-fuel mixture after combustion is sent as exhaust gas from each combustion chamber 12 to the exhaust passage 18 and purified by a catalytic converter 19 provided in the passage 18.

  In the internal combustion engine 11, the combustion chamber 12 and the intake passage 13 are communicated and blocked by the opening / closing operation of the intake valve 21, and the combustion chamber 12 and the exhaust passage 18 are communicated and blocked by the opening / closing operation of the exhaust valve 22. The The intake valve 21 and the exhaust valve 22 open and close in accordance with the rotation of the intake camshaft 23 and the exhaust camshaft 24 to which the rotation of the crankshaft 17 is transmitted.

  A variable valve mechanism 31 is provided between the intake camshaft 23 and the intake valve 21 to vary the maximum lift amount and the operating angle of the valve 21 (that is, the operating angle of the intake cam that opens and closes the intake valve 21). ing. These maximum lift amount and operating angle are variably controlled through driving of the variable valve mechanism 31 based on a command signal (drive command) from the electronic control device 41.

  FIG. 2 shows how the maximum lift amount and the operating angle are changed by driving the variable valve mechanism 31. As can be seen from the characteristic curve shown in the figure, the maximum lift amount and the operating angle change in synchronization with each other. For example, the maximum lift amount decreases as the operating angle decreases. The fact that the operating angle becomes smaller means that the opening timing and closing timing of the intake valve 21 are close to each other, and that the opening period of the intake valve 21 is shortened. In the present embodiment, the maximum lift amount and the operating angle can be continuously changed between the characteristic curves shown in FIG.

  In the present embodiment through the variable valve mechanism 31, the adjustment of the amount of air sucked into the combustion chamber 12 (intake air amount adjustment) is performed by adjusting the maximum lift amount and the operating angle according to the engine operating state such as the load of the internal combustion engine 11. This is performed based on the variable control. That is, for example, by reducing the maximum lift amount and the operating angle through the variable control, the amount of air taken into the combustion chamber 12 is reduced. In this case, by reducing the throttle valve, the pumping loss can be reduced as compared with the aspect of reducing the intake air amount, that is, the output loss in the internal combustion engine 11 can be suppressed, and the fuel consumption can be improved. become able to.

Next, the electrical configuration (control system) in the control device for the internal combustion engine 11 will be described in detail (see FIG. 1).
The electronic control device 41 described above forms part of an engine control system that controls the operation of the internal combustion engine 11. Through this electronic control unit 41, fuel injection control of the fuel injection valve 14 in the internal combustion engine 11, ignition timing control of the spark plug 15, variable control of the maximum lift amount and operating angle, and the like are performed.

  The electronic control device 41 calculates the rotational speed (engine rotational speed) of the crankshaft 17 based on the signal from the crank angle sensor 45. Further, the electronic control device 41 is based on a signal from an air flow meter 47 provided in the intake passage 13 and an actual value (actual intake) of the amount of air (intake air amount) taken into the combustion chamber 12 through the intake passage 13. The actual amount of air, that is, the amount of intake air) is calculated. The actual intake air amount data thus obtained is used for determining the fuel injection amount in the fuel injection control.

  The electronic control device 41 outputs a command value (absolute amount) to the variable valve mechanism 31 so as to variably control the maximum lift amount and the operating angle. In the following, for convenience, the command value related to the maximum lift amount and the operating angle is simply referred to as “command value”.

  The ROM provided in the electronic control device 41 stores in advance a control map regarding the relationship between the command value and the theoretical value (theoretical absolute amount) of the intake air amount corresponding to the command value. This control map describes the above relationship under various engine speed conditions. Thereby, the electronic control unit 41, for example, when the internal combustion engine 11 is in a steady operation state such as an idle operation, the intake air amount theory corresponding to the command value is based on the engine rotational speed information from the crank angle sensor 45. The absolute amount can be calculated. Further, the electronic control unit 41 can calculate a theoretical value (theoretical change amount) of the change in the intake air amount according to the change amount of the command value.

  In the abnormality determining device for the variable valve mechanism 31 configured as described above, the presence or absence of abnormality of the mechanism 31 is determined based on the transition of the actual intake air amount. More specifically, the determination of the presence / absence of the abnormality in the present embodiment (hereinafter referred to as abnormality determination) is based on the theoretical change amount and actual change of the intake air amount according to the change amount of the command value in the drive command. This is based on a comparison with the quantity (actual value of change).

  FIG. 3 shows an example of the relationship between the command value and the intake air amount at a certain engine rotation speed during steady operation (for example, engine rotation speed during idle operation). A curve 100 indicated by a solid line in the figure relates to the theoretical absolute amount of the intake air amount corresponding to the command value. A curve 100max indicated by a broken line is set as an upper limit of a normal range (a range that can be regarded as normal) regarding the relationship between the command value and the actual intake air amount, and the curve 100min is also set as the lower limit thereof. It is a thing.

  In the present embodiment, the absolute value of the difference between the actual change amount of the intake air amount and the theoretical change amount when the command value is changed by a predetermined amount, that is, the actual change of the intake air amount according to the change amount of the command value. When the absolute value of the difference between the amount and the theoretical change amount becomes larger than a predetermined reference value A, it is determined that “the variable valve mechanism 31 is abnormal”.

  That is, the actual change amount of the intake air amount according to the predetermined change amount da of the command value is, for example, the theoretical value curve 100 as shown by the actual change amount ds1 in the actual value curve 101 illustrated by a one-dot chain line in FIG. When the theoretical change amount ds0 at is smaller than that of the lower limit curve 100 min, it is determined that “the variable valve mechanism 31 is abnormal”. This abnormality is that the actual change amount of the intake air amount becomes too small with respect to the change amount when the command value is changed in the increasing direction or the decreasing direction.

  Further, the actual change amount of the intake air amount according to the predetermined change amount da of the command value is, for example, the theoretical value in the theoretical value curve 100 as in the actual change amount ds2 in the actual value curve 102 exemplified by the alternate long and short dash line. When the change amount ds0 becomes larger than that of the upper limit curve 100max, it is determined that “the variable valve mechanism 31 is abnormal”. This abnormality is that the actual change amount of the intake air amount becomes excessive with respect to the change amount when the command value is changed in the increasing direction or the decreasing direction.

  On the other hand, if the actual change amount of the intake air amount according to the predetermined change amount da of the command value is less than or equal to the upper limit curve 100max and greater than or equal to the lower limit curve 100min, that is, the normal range. Is determined to be “no abnormality in the variable valve mechanism 31”.

  Hereinafter, procedures such as the abnormality determination process will be described with reference to the flowcharts of FIGS. 4 and 5. These control routines are executed through the electronic control unit 41, for example, by interruption at predetermined time intervals.

First, a control routine related to the abnormality determination process in FIG. 4 will be described.
In this control routine, first, it is determined whether or not a precondition for changing the command value is satisfied (step S110). Examples of the precondition include that the internal combustion engine 11 is in a state suitable for performing the abnormality determination, such as being in a steady operation state such as an idle operation. This step S110 process is repeatedly executed until it is determined that the precondition is satisfied (step S110: YES).

  Then, as the precondition is satisfied, the process proceeds to step S120. Here, the command value is changed in an increasing direction from the current value by a predetermined amount (for example, the change amount da), and a drive command at the command value is issued to the variable valve mechanism 31. Then, the process proceeds to step S130, and the increase command flag is set to “1”.

  In the next step S140, it is determined whether or not an elapsed time since the change of the command value has reached a predetermined value. The predetermined time serving as a reference for this determination is set in consideration of a response delay from the time when the drive command is issued until the variable valve mechanism 31 starts driving. If it is determined that the elapsed time has reached a predetermined value (step S140: YES), the process proceeds to step S150, assuming that sufficient time has passed to make an abnormality determination.

  In step S150, it is determined whether or not the absolute value of the difference between the theoretical change amount of the intake air amount and the actual change amount according to the change amount of the command value is larger than a predetermined reference value A. When this determination result is YES, that is, when the absolute value of the difference is larger than the reference value A, the actual change amount of the intake air amount according to the change amount of the command value is, for example, an upper limit curve. It is determined that there is an abnormality in the variable valve mechanism 31 because it is larger than that related to 100max or smaller than that related to the lower limit curve 100min (step S160).

  On the other hand, when the determination result in step S150 is NO, that is, when the absolute value of the difference is equal to or less than the reference value A, the actual change amount of the intake air amount according to the change amount of the command value is, for example, It is determined that there is no abnormality in the variable valve mechanism 31 as corresponding to the normal range (step S170).

  Next, the command value is returned to the value before the change or the normal value determined from the engine operating state (step S180), and the increase command flag is set to “0” (step S190). Thereafter, this control routine is terminated.

In this way, abnormality determination of the variable valve mechanism 31 is made based on the transition of the intake air amount.
In the present embodiment, the fuel injection amount in the fuel injection valve 14 is not reduced by the increase in the actual intake air amount due to the change in the command value in the increasing direction. It is appropriately controlled according to the amount of air. Therefore, when the actual intake air amount increases as compared with the normal intake air amount adjustment as described above, the output (torque) increases in the internal combustion engine 11, and if this increase becomes excessive, the driver is informed. Concerns such as discomfort arise.

  Therefore, in the present embodiment, when the actual intake air amount increases in accordance with the drive command, this is controlled so as to retard the ignition timing in the spark plug 15 in accordance with the increase. Hereinafter, the processing procedure of such ignition timing control will be described with reference to the flowchart of FIG.

  In this control routine, first, it is determined whether or not “1” is set in the increase command flag, that is, whether or not the command value has been increased (step S510). If the determination result is YES, the process proceeds to step S520 to determine whether or not the actual absolute amount of intake air has increased. That is, it is determined whether or not an increase in the actual absolute amount of the intake air amount has occurred due to an increase in the command value in the abnormality determination process of FIG.

  If the determination result is YES, that is, if it is determined that an increase in the actual absolute amount of the intake air amount has occurred, the process proceeds to step S530 to increase the actual absolute amount of the intake air amount. Accordingly, the ignition timing is retarded. In this process, the ignition timing is controlled so that, for example, the retard amount from the normal ignition timing increases as the actual change amount of the intake air amount increases.

  On the other hand, if the determination result in step S510 or step S520 is NO, the above-described ignition timing delay is not executed, and in step S540, the normal ignition timing is set according to the engine operating state and the like. Will be.

In the present embodiment, the following effects can be obtained.
(1) According to this embodiment, based on the transition of the intake air amount (actual value) when a drive command is issued to the variable valve mechanism 31 so as to change the maximum lift amount and operating angle of the intake valve 21. Whether there is an abnormality in the mechanism 31 is determined. Therefore, when the above determination is made, it is not necessary to provide a special sensor for the determination by diverting the detection result using an existing sensor (for example, the air flow meter 47) used for detecting the intake air amount.

  In addition, among a plurality of linked members interposed on the power transmission path between the actuator and the intake valve that are driven to change the maximum lift amount or the like, for example, the configuration described in Patent Document 1 above, Even if an abnormality occurs in the correlation between the members (correlation regarding the displacement amount or the like), the above determination can be performed accurately.

  (2) When the actual intake air amount increases according to the drive command, the ignition timing is retarded according to the increase. According to this, an increase in the output (torque) of the internal combustion engine 11 accompanying an increase in the actual intake air amount according to the drive command is suppressed. That is, the generation of excessive output during the determination is suppressed.

(Second Embodiment)
In the second embodiment, the presence or absence of abnormality in the variable valve mechanism 31 is determined based on a comparison between the theoretical absolute amount and the actual absolute amount of the intake air amount corresponding to the command value (absolute amount) in the drive command. In other respects, the configuration is the same as that of the first embodiment.

  FIG. 6 shows an example of the relationship between the command value and the intake air amount at a certain engine rotation speed during normal operation (for example, engine rotation speed during idle operation). A curve 200 indicated by a solid line in the figure relates to the theoretical absolute amount of the intake air amount corresponding to the command value. A curve 200max indicated by a broken line is set as an upper limit of a normal range (a range that can be regarded as normal) regarding the relationship between the command value and the actual intake air amount. Similarly, the curve 200min is set as the lower limit. It is a thing. In the figure, the theoretical value curve 200 and the upper limit curve 200max are set such that the difference between the intake air amounts corresponding to the same command value is constant. Similarly to the above, the theoretical value curve 200 and the lower limit curve 200 min are set so that the difference between the intake air amounts corresponding to the same command value is constant.

  In the present embodiment, when the absolute value of the difference between the theoretical absolute amount and the actual absolute amount of the intake air amount according to the command value becomes larger than a predetermined reference value B, this is indicated as “variable valve mechanism 31. It is judged that there is an abnormality. Incidentally, in the present embodiment, when the reference value B is obtained by subtracting the intake air amount corresponding to the same command value in the theoretical value curve 200 from the intake air amount corresponding to the arbitrary command value in the upper limit curve 200max. Is set equal to the difference between Similarly, the reference value B is set equal to the difference when the intake air amount corresponding to an arbitrary command value in the theoretical value curve 200 is subtracted from the intake air amount corresponding to the same command value in the lower limit curve 200 min. Has been.

  That is, for example, as shown in the figure, after changing the command value from an arbitrary value (in the figure, the command value corresponding to the dot S1 is increased by the change amount db), the actual absolute amount of the intake air amount is within the normal range. If it is off, it is determined that “the variable valve mechanism 31 is abnormal”. For example, in the state indicated by the dot S2 in the figure, the actual absolute amount of the intake air corresponding to the same command value is larger than that for the upper limit curve 200max. The actual absolute amount of the corresponding intake air amount is excessive. Further, regarding the state indicated by the dot S3, the actual absolute amount of the intake air amount corresponding to the command value is smaller than that of the lower limit curve 200 min, that is, the suction according to the command value after the change. The actual absolute amount of air is too small. That is, when the actual absolute amount of the intake air amount after the change of the command value is in the state indicated by the dots S2 and S3, it is determined that the abnormality is present.

  On the other hand, in the state indicated by the dot S4, the actual absolute amount of the intake air amount corresponding to the command value is less than that for the upper limit curve 200max and more than that for the lower limit curve 200min. Is determined as “no abnormality in the variable valve mechanism 31”.

  In addition, when the abnormality determination is performed based on the comparison between the theoretical absolute amount of the intake air amount corresponding to the command value and the actual absolute amount as described above, the command value is not changed as described above. It is possible to make the same determination. However, in this embodiment, the command value is not changed, that is, the abnormality after the command value is changed so as to enable detection of an abnormality that may be overlooked in the abnormality determination in the “static state”. Judgment is made. That is, for example, when abnormality such as sticking occurs in the variable valve mechanism 31 while the normal state as indicated by the dot S1 is continued for a long time, the abnormality is detected in the abnormality determination in the “static state”. Can not do it. In this respect, the detection of such an abnormality (determination of “abnormality”) can be made by changing the command value from the state of the dot S1 and referring to the actual absolute amount of the intake air thereafter, as in the present embodiment. It becomes possible.

  Hereinafter, a procedure such as abnormality determination processing according to the present embodiment, which is executed by the time interruption at predetermined time intervals through the electronic control device 41, will be described with reference to the flowcharts of FIGS.

First, a control routine related to the abnormality determination process in FIG. 7 will be described. Each step process in this control routine is the same as that in FIG. 4 except for step S250.
That is, the processes in steps S210, S220, S230, S240, S260, S270, S280, and S290 are the same as those in steps S110, S120, S130, S140, S160, S170, S180, and S190 in FIG. Has become.

  Therefore, in this control routine, in step S250, it is determined whether or not the absolute value of the difference between the theoretical absolute amount and the actual absolute amount of the intake air amount is larger than a predetermined reference value B. Therefore, it is determined that the variable valve mechanism 31 is “abnormal”, and if it is NO, it is determined “abnormal”.

  As in the first embodiment, the increase in the output (torque) of the internal combustion engine 11 due to the increase in the actual intake air amount corresponding to the drive command is suppressed through the execution of the ignition timing control process shown in FIG. I have to.

Also in this embodiment, the same effects as the above (1) and (2) can be obtained.
(Third embodiment)
In the third embodiment, the intake air amount is adjusted through adjustment of the throttle opening in addition to the intake air amount adjustment through variable control of the maximum lift amount and the operating angle. This is different from the first and second embodiments described above. Therefore, in the following, such differences will be mainly described, and the same components as those in the first and second embodiments are denoted by the same reference numerals in the drawings, and redundant description is omitted.

  As shown in FIG. 8, in the internal combustion engine 11 of the present embodiment, a throttle valve 51 is provided in the middle of the intake passage 13 so that the throttle opening is adjusted based on a drive command issued from the electronic control unit 41. It has become. In the present embodiment, the intake air amount is adjusted through the adjustment of the throttle opening together with the above-described variable control of the maximum lift amount and the operating angle.

  Further, in the present embodiment, the electronic control unit 41 is configured to change the maximum lift amount and the operating angle so that the maximum lift amount and the operating angle are changed in a state where the above-described preconditions (for example, the internal combustion engine 11 is in a steady operation state) are satisfied. When the value is changed, the throttle opening is adjusted based on the change amount of the command value so that the actual intake air amount is kept constant. The intake air amount adjustment by both the variable control of the maximum lift amount and the operating angle and the adjustment of the throttle opening is, for example, a region downstream of the throttle valve 51 in the intake passage 13 while keeping the actual intake air amount constant. This is done, for example, when changing the pressure.

  Thus, in the present embodiment, the throttle opening is adjusted so as to eliminate the change in the actual intake air amount accompanying the change in the maximum lift amount and the operating angle. In such an internal combustion engine 11, for example, if there is no abnormality in the variable valve mechanism 31, the actual intake air amount is held constant even if the command value is changed. However, for example, when an abnormality occurs in the variable valve mechanism 31 and the maximum lift amount and the operating angle are not changed according to the drive command, the throttle opening is adjusted based on the change amount of the command value. As a result, the actual intake air amount cannot be kept constant, that is, the actual intake air amount thereafter changes. In the present embodiment, the abnormality determination is performed based on the presence or absence of such a change in the actual intake air amount.

  Hereinafter, a procedure such as abnormality determination processing according to the present embodiment, which is executed by the time interruption at predetermined intervals through the electronic control device 41, will be described with reference to the flowcharts of FIGS. It should be noted that the processing related to the adjustment of the throttle opening is executed in parallel with the processing shown in FIGS. 5 and 9 through the electronic control device 41, for example, by interruption at predetermined time intervals.

First, a control routine related to the abnormality determination process in FIG. 9 will be described. Each step process in this control routine is the same as that in FIG. 4 except for step S350.
That is, the processes of steps S310, S320, S330, S340, S360, S370, S380, and S390 are the same as the processes of steps S110, S120, S130, S140, S160, S170, S180, and S190 in FIG. Has become.

  Therefore, in this control routine, it is determined whether or not the actual absolute amount of the intake air amount has changed in step S350. If this determination result is YES, it is determined that the variable valve mechanism 31 is “abnormal”, and if NO. Is determined as “no abnormality”.

  As in the first and second embodiments, the increase in the output (torque) of the internal combustion engine 11 when the actual intake air amount increases is suppressed through the execution of the ignition timing control process shown in FIG. Yes.

In the present embodiment, the same effects as the above (1) and (2) can be obtained.
In addition, embodiment is not limited above, For example, it is good also as the following aspects.

  In each of the above embodiments, the abnormality determination is performed based on the transition of the intake air amount (actual value) when the command value is changed in the increasing direction. However, the present invention is not limited to this, and the command value is decreased. You may make it perform based on the said transition when changing to a direction.

  In the first embodiment, the abnormality determination is performed based on the comparison between the theoretical change amount and the actual change amount of the intake air amount according to the change amount of the command value. You may make it perform based on ratio (For example, the value of "ds1 / da" in FIG. 3, "ds2 / da", etc.) etc. of FIG. In this case, for example, when the ratio of the actual change amount of the intake air amount to the change amount of the command value deviates from a predetermined range (for example, a range corresponding to the normal range), it is determined that the variable valve mechanism 31 is abnormal. .

The schematic block diagram of the abnormality determination apparatus applied to the variable valve mechanism of 1st Embodiment. The figure which shows the relationship between the lift amount and operating angle of the intake valve in 1st Embodiment. The figure which shows the relationship between the command value and intake air amount in 1st Embodiment. The flowchart of the abnormality determination process in 1st Embodiment. The flowchart of the ignition timing control process in 1st Embodiment. The figure which shows the relationship between the command value and intake air amount in 2nd Embodiment. The flowchart of the abnormality determination process in 2nd Embodiment. The schematic block diagram of the abnormality determination apparatus applied to the variable valve mechanism of 3rd Embodiment. The flowchart of the abnormality determination process in 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Internal combustion engine, 21 ... Intake valve, 31 ... Variable valve mechanism, 41 ... Electronic control unit, 51 ... Throttle valve

Claims (6)

An abnormality determination device for a variable valve mechanism that determines whether or not there is an abnormality in a variable valve mechanism that varies a lift time area of an intake valve of an internal combustion engine,
Abnormality of the variable valve mechanism that detects the transition of the intake air amount while issuing a drive command to the variable valve mechanism so as to change the lift time area of the intake valve, and determines the presence or absence of the abnormality based on the detection result Judgment device. The determination as to whether or not there is an abnormality is made based on a comparison between a theoretical change amount and an actual change amount of the intake air amount according to a change amount of a command value of the lift time area in the drive command. An abnormality determination device for a variable valve mechanism. The abnormality determination of the variable valve mechanism according to claim 1, wherein the determination of the presence or absence of the abnormality is performed based on a ratio of an actual change amount of the intake air amount to a change amount of the command value of the lift time area in the drive command. apparatus. The variable valve according to claim 1, wherein the determination of the presence or absence of the abnormality is performed based on a comparison between a theoretical absolute amount and an actual absolute amount of the intake air amount according to a command value of the lift time area in the drive command. Mechanism abnormality determination device. An abnormality determination device for a variable valve mechanism that determines whether or not there is an abnormality in a variable valve mechanism that varies a lift time area of an intake valve of an internal combustion engine,
While issuing a drive command to the variable valve mechanism so that the lift time area of the intake valve is changed, the throttle opening is set based on the change amount of the command value in the drive command so that the intake air amount is kept constant. An abnormality determination device for a variable valve mechanism, characterized in that the abnormality is determined to be present when a change has occurred in a subsequent intake air amount. The abnormality determination device for a variable valve mechanism according to any one of claims 1 to 5, wherein when the intake air amount increases according to the drive command, the ignition timing is retarded according to the increase.

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