JP4339572B2 - Control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an internal combustion engine provided with a variable intake valve mechanism capable of controlling the intake air amount by varying the control amount of the intake valve of the internal combustion engine.
[0002]
[Prior art]
In recent years, an internal combustion engine mounted on a vehicle is provided with a variable intake valve mechanism that varies a valve control amount such as a lift amount and opening / closing timing of the intake valve, and the valve of the intake valve according to the accelerator opening, the engine operating state, etc. There is one that can control the intake air amount by varying the control amount. The intake air amount control by this variable intake valve control can reduce the intake air amount without reducing the intake passage with the throttle valve by reducing the lift amount and the valve opening period of the intake valve. There is an advantage that fuel consumption can be improved by reducing.
[0003]
In the conventional intake air amount control by general throttle valve control, the throttle valve opening is reduced to reduce the intake air amount at low load, so the intake air pressure on the downstream side of the throttle valve becomes quite negative. However, in the intake air amount control by the variable intake valve control, the intake valve amount is controlled by changing the lift amount and the valve opening period of the intake valve with the throttle valve opened widely. Regardless of the load, the pressure of the intake air downstream of the throttle valve is maintained at approximately atmospheric pressure, and even at low load, approximately atmospheric pressure air is drawn into the cylinder from the intake port. For this reason, in intake air amount control by variable intake valve control, the flow of air flowing through the intake port at a low load is gentle compared to intake air amount control by throttle valve control, and fuel adhering to the wall of the intake port ( There is a tendency for the vaporization characteristics of the wet fuel) and the flow characteristics of the in-cylinder mixture to decrease. In addition, the intake valve closing timing is advanced from the intake bottom dead center so as to shorten the intake valve opening time at low load, so the piston moves down even after the intake valve closes, and mixing in the cylinder There is a tendency for the air to expand and the temperature to drop. For these reasons, in the intake air amount control by the variable intake valve control, the combustion state may deteriorate at a low load, which may adversely affect drivability and exhaust emission.
[0004]
As a countermeasure against this, as shown in Patent Document 1 (Japanese Patent Application Laid-Open No. 2001-159341), when the intake air amount control by the variable intake valve control is performed, a specific operation condition (for example, idle operation or During low-load operation when the engine is cold, the intake air amount control mode is switched from intake air amount control by variable intake valve control to intake air amount control by throttle valve control. For example, the intake air amount is controlled by the throttle valve control while being fixed at the maximum value to prevent deterioration of the combustion state, and the intake air amount control by the variable intake valve control is performed in the normal operation condition other than the specific operation condition. There is something to do.
[0005]
[Patent Document 1]
JP 2001-159341 A (second page, etc.)
[0006]
[Problems to be solved by the invention]
By the way, when the intake air amount control by the variable intake valve control is performed, the operating condition in which the combustion state is deteriorated may change due to a change in the environment (temperature, humidity, atmospheric pressure, etc.) surrounding the vehicle. However, in the method of the above-mentioned patent document 1, since the intake air amount control by the throttle valve control is always switched under the specific operating conditions set in advance, even under the operating conditions where the combustion state does not actually deteriorate due to environmental changes or the like. However, there is a drawback that the intake air amount control by the throttle valve control may be switched, and the effect of the intake air amount control by the variable intake valve control cannot be fully utilized.
[0007]
In addition, in intake air amount control by variable intake valve control, the lift amount of the intake valve becomes small at low loads, so variation in the actual lift amount with respect to the target lift amount in each cylinder (variation due to component tolerance or assembly tolerance of each cylinder) ) Increases, and variation in intake air amount between cylinders tends to increase. For this reason, when the load is low, the variation in torque and the variation in air-fuel ratio between cylinders may be increased due to the influence of the variation in intake air amount between the cylinders, and drivability and exhaust emission may deteriorate. Against this problem, it is conceivable to switch to intake air amount control by throttle valve control at low load.
[0008]
However, the variation in the actual lift amount has individual differences and changes over time, and therefore, the variation in intake air amount between cylinders does not always increase at the time of low load of intake air amount control by variable intake valve control. Therefore, if the intake air amount control based on the throttle valve control is always switched at low load, the intake air amount control based on the throttle valve control is actually switched even if there is no adverse effect due to variations in the intake air amount among the cylinders. As a result, the effect of the intake air amount control by the variable intake valve control cannot be fully utilized.
[0009]
The present invention has been made in consideration of these circumstances. ,spirit This is to increase the effect of intake air amount control by variable intake valve control while reducing the variation in intake air amount between cylinders.
[0010]
[Means for Solving the Problems]
[0022]
Accordingly, in claim 1 of the present invention, the inter-cylinder variation value representing the variation in the intake air amount between the cylinders of the internal combustion engine is detected by the inter-cylinder variation detecting means, and based on the inter-cylinder variation value. When the variation value between the cylinders is larger than a predetermined determination value Control amount of intake valve To control the intake valve to increase the valve lift and to suppress the change in intake air Control the amount of throttle valve control Adjust the throttle opening to decrease or increase. The intake air amount is controlled, and the inter-cylinder variation value is detected based on at least one of the intake air amount, intake pipe pressure, rotational fluctuation, in-cylinder pressure, ion current, and air-fuel ratio.
[0023]
In this way, the control amount of the intake valve and the control amount of the throttle valve can be controlled according to the actually detected inter-cylinder variation value. Therefore, when the inter-cylinder variation value is large, the intake air amount between the cylinders When the control value of the intake valve or the control value of the throttle valve is controlled in the direction to reduce the variation, and the variation value between cylinders is small, the control amount of the intake valve in the direction to increase the effect of the intake air amount control by the variable intake valve control And the control amount of the throttle valve can be controlled. Thereby, the effect of the intake air amount control by the variable intake valve control can be increased while reducing the variation in the intake air amount between the cylinders generated by the intake air amount control by the variable intake valve control.
[0024]
In this case, the claim 1 In the invention according to the present invention, the inter-cylinder variation value is detected based on at least one of the intake air amount, intake pipe pressure, rotational fluctuation, in-cylinder pressure, ion current, and air-fuel ratio. Since the intake air pressure detected by the intake pipe and the intake pipe pressure detected by the intake pipe pressure sensor, etc. change in accordance with the intake stroke of each cylinder, if the intake air quantity or intake pipe pressure is monitored, the intake air between the cylinders It is possible to detect an inter-cylinder variation value that reflects the amount variation. In addition, since the air-fuel ratio of each cylinder changes according to the intake air amount of each cylinder, if the air-fuel ratio detected by an air-fuel ratio sensor or the like is monitored, the inter-cylinder variation value reflecting the intake air amount variation between the cylinders can be obtained. Can be detected. Also, the combustion state of each cylinder changes according to the intake air amount of each cylinder, and the rotational fluctuation, in-cylinder pressure, and ionic current change according to the combustion state. By monitoring, it is possible to detect a variation value between cylinders that reflects a variation in intake air amount between the cylinders.
[0025]
By the way, when the intake air amount control using the inter-cylinder variation value changes in a direction in which the intake air amount variation (cylinder variation value) between the cylinders increases, the intake air amount variation (cylinder variation value) between the cylinders. In order to control the intake valve control amount and throttle valve control amount in the direction of decreasing the intake air amount, the variation in intake air amount between cylinders (the variation value between cylinders) is small during normal operation. If the intake valve control amount is greatly changed while the intake air amount variation between cylinders (cylinder variation value) increases to some extent due to the above, the intake air amount variation (cylinder variation value) between cylinders will increase more and more. There is a possibility.
[0028]
Claims 2 As described above, it may be determined whether there is an abnormality in the components of the intake air amount control system by determining whether the opening degree of the throttle valve is equal to or less than a predetermined abnormality determination value by the abnormality determination means. Normally, in order to reduce the pumping loss and improve fuel efficiency, the throttle valve opening degree is set to a predetermined value in order to control the intake air amount by varying the control amount of the intake valve while the throttle valve is wide open. Whether or not there is an abnormality in the components of the intake air amount control system can be easily determined based on whether or not it is equal to or less than the abnormality determination value.
[0029]
In this case, the claim 3 As described above, when an abnormality is detected by the abnormality determination means, the intake air amount control at the time of abnormality is performed in which the intake valve control amount is fixed and the intake air amount is controlled by controlling the throttle valve opening. good. As described above, when the abnormality is detected, it is more likely that the intake air amount can be controlled with higher accuracy than the case where the intake air amount is controlled by the variable valve control when the intake air amount is controlled by the throttle control.
[0030]
At this time, the claim 4 As described above, during the execution of the abnormal intake air amount control, when the inter-cylinder variation detecting value detected by the inter-cylinder variation detecting means is smaller than a predetermined value, it is determined that the variable intake valve mechanism is abnormal. good. During the execution of the abnormal intake air amount control, the intake air amount is controlled by the throttle control. Therefore, the variation value between cylinders is reduced by the abnormal intake air amount control (throttle control). This means that the intake air amount is controlled with high accuracy (the drive system and control system of the throttle valve are normal). Therefore, if the inter-cylinder variation value becomes smaller during execution of the abnormal intake air amount control, it can be determined that the variable intake valve mechanism is abnormal.
[0031]
Claims 5 As described above, whether or not the variable intake valve mechanism is operating normally when the inter-cylinder variation detection value detected by the inter-cylinder variation detection means is equal to or greater than a predetermined value during the execution of the abnormal intake air amount control. If it is determined that the motor is operating normally, it may be determined that the throttle valve drive system / control system is abnormal. That is, when the abnormal intake air amount control is executed, the variation value between the cylinders increases, which means that the intake air amount variation between the cylinders is not reduced even by the intake air amount control by the throttle control. This means that there is a possibility that the drive system / control system of the system is out of order. In this case, there is a possibility that both the throttle valve drive system and control system and the variable intake valve mechanism are out of order, so it is determined whether or not the variable intake valve mechanism is operating normally. If it is determined that there is an abnormality, it can be determined that the drive system / control system of the throttle valve is abnormal.
[0032]
At this time, the claim 6 As described above, it is preferable to determine whether or not the variable intake valve mechanism is operating normally by comparing the output of the sensor that detects the position of the intake valve and the control amount of the intake valve. In this way, it can be accurately determined whether or not the variable intake valve mechanism is operating normally.
[0033]
Claims 7 As described above, the intake valve control amount and / or the throttle valve control amount set by the intake air amount control unit is learned by the learning unit, and the intake air amount control unit is based on the control amount learned by the learning unit. The control amount may be set. In this way, the control amount of the intake valve and the control amount of the throttle valve can be quickly controlled to appropriate values without being affected by manufacturing variations of the control system, changes with time, and the like.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
<< Embodiment (1) >>
Hereinafter, an embodiment (1) of the present invention will be described with reference to FIGS. First, a schematic configuration of the entire engine control system will be described with reference to FIG. An air cleaner 13 is provided at the most upstream portion of the intake pipe 12 of the engine 11 that is an internal combustion engine, and an air flow meter 14 that detects the intake air amount is provided downstream of the air cleaner 13. On the downstream side of the air flow meter 14, a throttle valve 15 whose opening is adjusted by a DC motor or the like and a throttle opening sensor 16 for detecting the throttle opening are provided.
[0035]
Further, a surge tank 17 is provided on the downstream side of the throttle valve 15, and an intake pipe pressure sensor 18 for detecting the intake pipe pressure is provided in the surge tank 17. The surge tank 17 is provided with an intake manifold 19 for introducing air into each cylinder of the engine 11, and a fuel injection valve 20 for injecting fuel is attached in the vicinity of the intake port of the intake manifold 19 of each cylinder. Yes. A spark plug 21 is attached to each cylinder of the engine 11 for each cylinder, and the air-fuel mixture in the cylinder is ignited by spark discharge of each spark plug 21.
[0036]
Further, the intake valve 28 and the exhaust valve 29 of the engine 11 are provided with variable valve lift mechanisms 30 and 31 for varying the valve lift amount, respectively. Further, the intake valve 28 and the exhaust valve 29 may each be provided with a variable valve timing mechanism that varies the valve timing (opening / closing timing). The exhaust valve 29 may be provided with only the variable valve timing mechanism without providing the variable valve lift mechanism 31.
[0037]
On the other hand, the exhaust pipe 22 of the engine 11 is provided with a catalyst 23 such as a three-way catalyst that purifies CO, HC, NOx, etc. in the exhaust gas, and detects the air-fuel ratio of the exhaust gas upstream of the catalyst 23. An air-fuel ratio sensor 24 is provided. Further, a water temperature sensor 25 that detects the coolant temperature and a crank angle sensor 26 that outputs a pulse signal each time the crankshaft of the engine 11 rotates by a certain crank angle (for example, 30 ° C. A) are attached to the cylinder block of the engine 11. It has been. Based on the output signal of the crank angle sensor 26, the crank angle and the engine speed are detected.
[0038]
Outputs of these various sensors are input to an engine control circuit (hereinafter referred to as “ECU”) 27. The ECU 27 is mainly composed of a microcomputer, and executes various engine control programs stored in a built-in ROM (storage medium) to thereby determine the fuel injection amount of the fuel injection valve 20 according to the engine operating state. The ignition timing of the spark plug 21 is controlled.
[0039]
Next, the configuration of the variable valve lift mechanism (variable intake valve lift mechanism) 30 of the intake valve 28 will be described with reference to FIG. Note that the variable valve lift mechanism (variable exhaust valve lift mechanism) 31 of the exhaust valve 29 has substantially the same configuration as the variable intake valve lift mechanism 30, and thus the description thereof is omitted.
[0040]
As shown in FIG. 2, a link arm 34 is provided between the camshaft 32 and the rocker arm 33 for driving the intake valve 28, and a motor 41 such as a stepping motor is rotated above the link arm 34. A control shaft 35 that is driven by movement is provided. The control shaft 35 is provided with an eccentric cam 36 so as to be integrally rotatable, and the link arm 34 swings via a support shaft (not shown) at a position eccentric with respect to the axis of the eccentric cam 36. It is supported movably. A swing cam 38 is provided at the center of the link arm 34, and the side surface of the swing cam 38 is in contact with the outer peripheral surface of a cam 37 provided on the cam shaft 32. Further, a pressing cam 39 is provided at the lower end portion of the link arm 34, and the lower end surface of the pressing cam 39 is in contact with the upper end surface of the roller 40 provided at the central portion of the rocker arm 33.
[0041]
Accordingly, when the cam 37 rotates due to the rotation of the cam shaft 32, the swing cam 38 of the link arm 34 moves to the left and right following the outer peripheral surface shape of the cam 37, and the link arm 34 swings to the left and right. . When the link arm 34 swings left and right, the pressing cam 39 moves left and right. Therefore, the roller 40 of the rocker arm 33 moves up and down according to the lower end surface shape of the pressing cam 39, and the rocker arm 33 swings up and down. Move. The intake bubble 28 moves up and down by the up and down movement of the rocker arm 33.
[0042]
On the other hand, when the eccentric cam 36 is rotated by the rotation of the control shaft 35, the position of the support shaft of the link arm 34 is moved, and the initial contact point position between the pressing cam 39 of the link arm 34 and the roller 40 of the rocker arm 33 is changed. Change. Also, the lower end surface of the pressing cam 39 of the link arm 34 is formed with a base curved surface 39a with a curvature such that the pressing amount of the rocker arm 33 is 0 (the valve lift amount of the intake valve 28 is 0) on the left side. The pressing curved surface 39b is formed with such a curvature that the pressing amount of the rocker arm 33 increases (the valve lift amount of the intake valve 28 increases) as it goes rightward from the base curved surface 39a.
[0043]
In the high lift mode in which the valve lift amount of the intake valve 28 is increased, the initial contact point position between the pressing cam 39 of the link arm 34 and the roller 40 of the rocker arm 33 is moved rightward by the rotation of the control shaft 35. Let Thereby, when the pressing cam 39 moves to the left and right due to the rotation of the cam 37, the section of the lower end surface of the pressing cam 39 that contacts the roller 40 moves to the right, so that the maximum pressing amount of the rocker arm 33 increases. As a result, the maximum valve lift amount of the intake valve 28 increases, the period during which the rocker arm 33 is pressed becomes longer, and the valve opening period of the intake bubble 28 becomes longer.
[0044]
On the other hand, in the low lift mode in which the valve lift amount of the intake valve 28 is reduced, the initial contact point position between the pressing cam 39 of the link arm 34 and the roller 40 of the rocker arm 33 is set to the left by the rotation of the control shaft 35. Move to. As a result, when the pressing cam 39 moves to the left and right due to the rotation of the cam 37, the section of the lower end surface of the pressing cam 39 that contacts the roller 40 moves to the left, so that the maximum pressing amount of the rocker arm 33 is reduced. Accordingly, the maximum valve lift amount of the intake valve 28 is reduced, the period during which the rocker arm 33 is pressed is shortened, and the valve opening period of the intake bubble 28 is shortened.
[0045]
In the variable intake valve lift mechanism 30 described above, if the control shaft 35 is rotated by the motor 41, the initial contact point position between the pressing cam 39 of the link arm 34 and the roller 40 of the rocker arm 33 is continuously moved. The maximum valve lift amount and the valve opening period (hereinafter simply referred to as “valve lift amount”) of the intake valves 28 of all the cylinders can be continuously varied.
[0046]
The ECU 27 controls the variable intake valve lift mechanism 30 according to the target intake air amount set based on the accelerator opening and the like, and continuously varies the valve lift amount of the intake valve 28 to control the intake air amount. . In the case of a system using both the variable intake valve lift mechanism 30 and the variable intake valve timing mechanism, the intake air amount may be controlled by continuously varying both the valve lift amount and the valve timing.
[0047]
As described above, the intake air amount control by the variable intake valve control has the effect of reducing the pumping loss and improving the fuel consumption. However, the combustion state deteriorates at low load when the valve lift amount is reduced, and the driver is reduced. May adversely affect the performance and exhaust emissions.
[0048]
Therefore, the ECU 27 executes the intake air amount control program shown in FIG. 3 stored in the ROM to detect the combustion instability based on the rotational fluctuation or the like, and the combustion instability is determined from a predetermined determination value. When the combustion state tends to deteriorate, the valve lift amount and the throttle opening are corrected in a direction to stabilize the combustion state. On the other hand, when the degree of combustion instability is equal to or less than a predetermined determination value and the combustion state is stable, the valve lift amount and the throttle opening are corrected so as to increase the effect of intake air amount control by variable intake valve control. Hereinafter, the processing content of the intake air amount control program of FIG. 3 executed by the ECU 27 will be described.
[0049]
The intake air amount control program shown in FIG. 3 is executed in a predetermined cycle after an ignition switch (not shown) is turned on, and plays a role as intake air amount control means in the claims. When this program is started, first, in step 101, the warm-up of the engine 11 is completed depending on whether or not the coolant temperature detected by the water temperature sensor 25 is higher than a predetermined warm-up determination water temperature T0 (for example, 80 ° C.). It is determined whether or not.
[0050]
If it is determined in step 101 that the warm-up has not been completed, the process proceeds to step 102 where intake air amount control is performed by throttle valve control. In this case, with the valve lift amount (maximum valve lift amount and valve opening period) of the intake valve 28 fixed at, for example, a maximum value, the intake air amount is controlled by varying only the throttle opening.
[0051]
Thereafter, if it is determined in step 101 that the warm-up has been completed, the process proceeds to step 103, where a map of the throttle opening learning value GTA shown in FIG. And the throttle opening learning value GTA in the operation region corresponding to the target intake air amount GNtg) is read and set as the throttle opening TA.
TA = GTA
[0052]
The map shown in FIG. 4A is divided into a plurality of operating regions using the engine speed NE and the target intake air amount GNtg as parameters, and a throttle opening learning value GTA is stored for each operating region. .
[0053]
Thereafter, the routine proceeds to step 104, where a map of the valve lift learned value GVL shown in FIG. 4B is searched, and the valve in the operating region corresponding to the current operating state (engine rotational speed NE and target intake air amount GNtg). The lift learning value GVL is read and set as the valve lift amount VL.
VL = GVL
[0054]
The map shown in FIG. 4B is divided into a plurality of operation regions using the engine speed NE and the target intake air amount GNtg as parameters, and a valve lift learning value GVL is stored for each operation region.
[0055]
Thereafter, the process proceeds to step 105, and the combustion instability is calculated. Focusing on the relationship that the value of the rotational fluctuation changes according to the combustion state of each cylinder, in this step 105, the combustion instability is calculated as follows based on the rotational fluctuation. First, the time T30 required for the crankshaft to rotate at a predetermined crank angle (for example, 30 ° C. A) is calculated based on the output signal of the crank angle sensor 26, and the maximum T30 is calculated for each period corresponding to the combustion stroke of each cylinder. The rotational fluctuation ΔNE of each cylinder is calculated based on the difference between the value and the minimum value. Then, the degree of variation (for example, standard deviation) of the rotational fluctuation ΔNE of each cylinder is calculated and used as the combustion instability. The process of step 105 serves as a combustion instability detection means in the claims.
[0056]
Since the in-cylinder pressure and ion current also change according to the combustion state of each cylinder, the instability of combustion may be calculated based on the in-cylinder pressure and ion current in step 105.
[0057]
When calculating the degree of combustion instability based on the in-cylinder pressure, an in-cylinder pressure sensor (not shown) is provided for each cylinder, and the in-cylinder pressure sensor for each cylinder is provided for each period corresponding to the combustion stroke of each cylinder. The in-cylinder pressure characteristic value (for example, the in-cylinder pressure peak value, average value, area, in-cylinder pressure detection value at a predetermined crank angle, etc.) is calculated based on the in-cylinder pressure detected in (5). Then, the degree of variation (for example, standard deviation) in the in-cylinder pressure characteristic value of each cylinder is calculated and set as the combustion instability.
[0058]
On the other hand, when calculating the combustion instability based on the ion current, the ion current characteristic value (peak) is calculated based on the ion current detected through the ignition plug 21 of each cylinder for each period corresponding to the combustion stroke of each cylinder. Value, average value, area, ion current detection value of a predetermined crank angle, etc.) are calculated, and the degree of dispersion (for example, standard deviation) of the ion current characteristic value of each cylinder is calculated as the combustion instability.
Further, the degree of combustion instability may be calculated based on two or more of rotational fluctuation, in-cylinder pressure, and ion current.
[0059]
After calculating the combustion instability, the routine proceeds to step 106, where the combustion instability is compared with a predetermined judgment value Krough, and if the combustion instability is larger than the judgment value Krough, it is judged that the combustion state tends to deteriorate. Then, the routine proceeds to step 107, and in order to stabilize the combustion state, the valve lift amount VL is increased and corrected by a predetermined amount kVL1 by the following equation.
VL = VL + kVL1
[0060]
On the other hand, if it is determined in step 106 that the combustion instability is equal to or less than the determination value Krough, it is determined that the combustion state is stable, and the routine proceeds to step 108 where variable intake valve control is performed. In order to increase the effect of the intake air amount control, the valve lift amount VL is corrected to decrease by a predetermined amount kVL2 by the following equation.
VL = VL-kVL2
[0061]
After the valve lift amount VL is corrected to increase or decrease in step 107 or 108, a change in the engine rotational speed NE (change in the intake air amount GN) due to the correction of the valve lift amount VL is performed by the processing in the following steps 109 to 111. Therefore, the throttle opening degree TA is corrected to be decreased or increased.
[0062]
First, at step 109, the engine rotational speed NE is compared with the target rotational speed NEtg. If the engine rotational speed NE is higher than the target rotational speed NEtg, the routine proceeds to step 110, where the throttle opening degree TA is set to a predetermined amount kTA1 by the following equation. Correct weight loss.
TA = TA-kTA1
[0063]
On the other hand, if it is determined that the engine rotational speed NE is equal to or lower than the target rotational speed NEtg, the routine proceeds to step 111, where the throttle opening degree TA is increased and corrected by a predetermined amount kTA2.
TA = TA + kTA2
[0064]
In step 109, it may be determined whether the intake air amount GN is larger than the target intake air amount GNtg. In general, the stability of the engine rotational speed NE is more important than the output torque during idle operation, and the output torque (intake air amount GN) is greater than the stability of the engine rotational speed NE during normal operation other than idle operation. ) During idling, it is determined in step 109 whether the engine speed NE is higher than the target speed NEtg. In normal operation other than idling, the intake air is determined in step 109. It may be determined whether or not the amount GN is larger than the target intake air amount GNtg.
[0065]
After the throttle opening TA is reduced or increased at step 110 or 111, the routine proceeds to step 112, where the throttle opening learning value GTA of the operating region read at step 103 is updated with the corrected throttle opening TA. .
GTA = TA
[0066]
Thereafter, the process proceeds to step 113, and the valve lift learned value GVL in the operation region read in step 104 is updated with the corrected valve lift amount VL.
GVL = VL
The processing of these steps 112 and 113 serves as learning means in the claims.
[0067]
According to this embodiment (1) described above, combustion instability is detected based on rotational fluctuations, etc., and when the combustion instability is greater than the judgment value Krough and the combustion state tends to deteriorate, combustion The valve lift amount VL is corrected to increase so as to stabilize the state, and when the combustion instability is equal to or less than the determination value Krough and the combustion state is stable, the effect of the intake air amount control by the variable intake valve control is increased. The valve lift amount VL is corrected to decrease. Further, the throttle opening degree TA is corrected to be decreased or increased so as to suppress the change in the engine speed NE (change in the intake air amount GN) due to the correction of the valve lift amount VL. This increases the fuel efficiency improvement effect of the intake air amount control by the variable intake valve control while preventing the deterioration of the combustion state caused by the intake air amount control by the variable intake valve control and improving the drivability and the exhaust emission. Can do.
[0068]
In this embodiment (1), the valve lift VL and the throttle opening TA set based on the combustion instability are stored as the valve lift learning value GVL and the throttle opening learning value GTA, and these valves are stored. Since the lift learning value GVL and the throttle opening learning value GTA are corrected and the next valve lift amount VL and throttle opening TA are set, there is no influence of manufacturing variations of the control system, changes over time, etc. The valve lift amount VL and the throttle opening degree TA can be quickly controlled to appropriate values.
[0069]
<< Embodiment (2) >>
Next, Embodiment (2) of this invention is demonstrated using FIG.6 and FIG.7.
In intake air amount control by variable intake valve control, the intake air amount variation between cylinders increases at low load when the valve lift amount is reduced, resulting in greater torque variation and air-fuel ratio variation between cylinders. There is concern that emissions will deteriorate.
[0070]
Therefore, in the present embodiment (2), by executing the intake air amount control program shown in FIG. 6, the inter-cylinder variation value representing the intake air amount variation between the cylinders is detected, and the inter-cylinder variation value is a predetermined value. When the value is larger than the determination value, the valve lift amount and the throttle opening are corrected in a direction to reduce the variation between cylinders. On the other hand, when the inter-cylinder variation value is equal to or smaller than a predetermined determination value, the valve lift amount and the throttle opening are corrected in a direction to increase the effect of intake air amount control by variable intake valve control.
[0071]
The program of FIG. 6 is obtained by changing the processing of steps 105 and 106 of the program of FIG. 3 described in the embodiment (1) to the processing of steps 105a and 106a, and other processing is the same as FIG. is there.
[0072]
When the intake air amount control program of FIG. 6 is started, in steps 101 to 104, after completion of warm-up, the throttle opening learning value GTA of the operation region corresponding to the current operation state is read, and is used as the throttle opening TA. At the same time, the valve lift learning value GVL of the operation region corresponding to the current operation state is read and set as the valve lift amount VL.
[0073]
Thereafter, the process proceeds to step 105a, and the inter-cylinder variation value representing the variation in intake air amount among the cylinders is calculated. As shown in FIG. 7, since intake pulsation occurs in the intake pipe 12 of the engine 11 corresponding to the intake stroke of each cylinder, the waveform of the intake pipe pressure detected by the intake pipe pressure sensor 18 is The pulsation waveform corresponding to the intake stroke, that is, the pulsation waveform reflecting the intake air amount of each cylinder.
[0074]
Therefore, in step 105a, the inter-cylinder variation value is calculated based on the intake pipe pressure detected by the intake pipe pressure sensor 18. In this case, the intake pipe pressure characteristic value (minimum value, maximum value, average value, amplitude value, area, trajectory length) based on the intake pipe pressure detected by the intake pipe pressure sensor 18 for each period corresponding to the intake stroke of each cylinder. Etc.). Then, the degree of variation (for example, standard deviation) in the intake pipe pressure characteristic value of each cylinder is calculated, and this is used as the variation value between cylinders. The processing in step 105a serves as a cylinder-to-cylinder variation detecting means in the claims.
[0075]
When the air flow meter 14 capable of detecting the backflow of the intake air is used, the waveform of the intake air amount detected by the air flow meter 14 is also a pulsation waveform corresponding to the intake stroke of each cylinder, that is, each cylinder. Since the pulsation waveform reflects the intake air amount, the inter-cylinder variation value may be calculated based on the intake air amount detected by the air flow meter 14. In this case, the intake air amount characteristic value (minimum value, maximum value, average value, amplitude value, area, trajectory length, etc.) based on the intake air amount detected by the air flow meter 14 for each period corresponding to the intake stroke of each cylinder. And the variation degree (for example, standard deviation) of the intake air amount characteristic value of each cylinder is calculated to obtain the variation value between cylinders.
[0076]
Alternatively, an intake air amount sensor may be provided in each intake manifold 19 of each cylinder, and the inter-cylinder variation value may be calculated based on the intake air amount of each cylinder detected by the intake air amount sensor of each cylinder.
[0077]
Further, since the air-fuel ratio of the exhaust gas of each cylinder changes according to the intake air amount of each cylinder, the inter-cylinder variation value may be calculated based on the air-fuel ratio of the exhaust gas detected by the air-fuel ratio sensor 24. good. In this case, the air-fuel ratio of each cylinder is estimated based on the output signal of the air-fuel ratio sensor 24 in consideration of the exhaust system delay time required until the exhaust gas discharged from the engine 11 is detected by the air-fuel ratio sensor 24. Then, the variation degree (for example, standard deviation) of the estimated air-fuel ratio of each cylinder is calculated to obtain the variation value between cylinders.
[0078]
Alternatively, air-fuel ratio characteristic values (average value, area, locus length, etc.) are calculated based on the air-fuel ratio detected by the air-fuel ratio sensor 24 for each period corresponding to the exhaust stroke of each cylinder, and the air-fuel ratio characteristics of each cylinder are calculated. A variation degree between values (for example, standard deviation) may be calculated to obtain an inter-cylinder variation value.
[0079]
In addition, the combustion state of each cylinder changes according to the intake air amount of each cylinder, and the rotational fluctuation, in-cylinder pressure, and ionic current change according to the combustion state. The inter-cylinder variation value may be calculated based on this.
[0080]
When calculating the inter-cylinder variation value based on the rotation fluctuation, the rotation fluctuation ΔNE of each cylinder is calculated based on the difference between the maximum value and the minimum value of T30 for each period corresponding to the combustion stroke of each cylinder. The degree of variation (for example, standard deviation) of the rotational fluctuation ΔNE is calculated to obtain the variation value between cylinders.
[0081]
When calculating the inter-cylinder variation value based on the in-cylinder pressure, the in-cylinder pressure is detected based on the in-cylinder pressure (see FIG. 5) detected by the in-cylinder pressure sensor of each cylinder for each period corresponding to the combustion stroke of each cylinder. A pressure characteristic value (peak value, average value, area, trajectory length, etc.) is calculated, and a variation degree (for example, standard deviation) of the in-cylinder pressure characteristic value of each cylinder is calculated as a variation value between cylinders.
[0082]
Alternatively, the inter-cylinder variation value may be calculated based on the in-cylinder pressure value immediately before ignition of each cylinder or the in-cylinder pressure characteristic value (average value, area, trajectory length, etc.) for a predetermined period before ignition. .
[0083]
Also, when calculating the inter-cylinder variation value based on the ionic current, the ionic current characteristic value (peak) is calculated based on the ionic current detected through the ignition plug 21 of each cylinder for each period corresponding to the combustion stroke of each cylinder. Value, average value, area, etc.), and the variation degree (for example, standard deviation) of the ion current characteristic value of each cylinder is calculated to obtain the variation value between cylinders.
Further, the inter-cylinder variation value may be calculated based on two or more of the intake pipe pressure, intake air amount, air-fuel ratio, rotation fluctuation, in-cylinder pressure, and ion current.
[0084]
After calculating the inter-cylinder variation value, the process proceeds to step 106a, where the inter-cylinder variation value is compared with the determination value Krough. If the inter-cylinder variation value is larger than the determination value Krough, the process proceeds to step 107, and the intake air amount between the cylinders In order to reduce the variation, the valve lift amount VL is corrected to be increased by a predetermined amount kVL1.
[0085]
On the other hand, if it is determined in step 106a that the inter-cylinder variation value is equal to or less than the determination value Krough, the process proceeds to step 108, in order to increase the effect of the intake air amount control by the variable intake valve control. The valve lift amount VL is corrected to decrease by a predetermined amount kVL2.
[0086]
Thereafter, the throttle opening degree TA is corrected to decrease or increase so as to suppress the change of the engine speed NE (change of the intake air amount GN) due to the correction of the valve lift amount VL (steps 109 to 111).
[0087]
Thereafter, the throttle opening learning value GTA is updated with the corrected throttle opening TA, and the valve lift learning value GVL is updated with the corrected valve lift VL (steps 112 and 113).
[0088]
In the present embodiment (2) described above, the cylinder-to-cylinder variation value representing the variation in the intake air amount between the cylinders is detected. The valve lift amount VL is corrected to increase so as to decrease, and when the inter-cylinder variation value is equal to or smaller than the determination value Krough, the valve lift amount VL is corrected to decrease so as to increase the effect of intake air amount control by variable intake valve control. Further, the throttle opening degree TA is corrected to be decreased or increased so as to suppress the change in the engine speed NE (change in the intake air amount GN) due to the correction of the valve lift amount VL. As a result, the fuel consumption improvement effect of the intake air amount control by the variable intake valve control is improved while reducing the variation in the intake air amount between the cylinders generated by the intake air amount control by the variable intake valve control and improving the drivability and the exhaust emission. Can be increased.
[0089]
In each of the above embodiments (1) and (2), first, after correcting the valve lift amount VL based on the degree of combustion instability (or the variation value between cylinders), the throttle opening degree TA is corrected. On the contrary, first, the valve lift amount VL may be corrected after the throttle opening degree TA is corrected based on the degree of combustion instability (or the variation value between cylinders).
[0090]
In each of the above embodiments (1) and (2), the stepping motor is used as the drive source of the variable valve lift mechanisms 30 and 31, but other electromagnetic actuators or hydraulic actuators are used. Also good. Alternatively, the valve lift amount, the valve timing, and the like may be varied by directly driving the intake valve 28 and the exhaust valve 29 with an electromagnetic actuator.
[0091]
<< Embodiment (3) >>
Next, an embodiment (3) of the present invention will be described with reference to FIGS. This embodiment (3) may be implemented in combination with the embodiment (1) or the embodiment (2).
[0092]
In this embodiment (3), the execution region of intake air amount control by variable intake valve control is limited to a region where combustion stability can be secured to some extent (or a region where variations in intake air amount between cylinders can be reduced to some extent), and An abnormality diagnosis function and a fail-safe function are provided. The processing contents of each program that realizes these functions will be described below.
[0093]
[Variable intake valve control execution flag set / reset]
The variable intake valve control execution flag set / reset program shown in FIG. 8 is executed in a predetermined cycle after an ignition switch (not shown) is turned on, and also serves as a control amount restriction control means in the claims. When this program is started, first, in step 201, it is determined whether or not the combustion instability is equal to or greater than a predetermined value K1 (or whether the inter-cylinder variation value is equal to or greater than a predetermined value K2). Here, the predetermined value K1 (or K2) is a determination value that determines the boundary of the execution region of the variable intake valve control, and may be set to an appropriate value through experiments or simulations.
[0094]
When the degree of combustion instability is smaller than the predetermined value K1 (or when the inter-cylinder variation value is smaller than the predetermined value K2), combustion stability can be ensured even if intake air amount control is performed by variable intake valve control (or In step 202, the variable intake valve control execution flag is set to “1”, and intake air amount control by variable intake valve control is executed.
[0095]
In contrast, when the degree of combustion instability is equal to or greater than the predetermined value K1 (or when the inter-cylinder variation value is equal to or greater than the predetermined value K2), when the intake air amount control by the variable intake valve control is performed, the combustion state is It is determined that there is a possibility of deterioration (or there is a possibility that the variation in intake air amount between cylinders will increase), the process proceeds to step 203, the variable intake valve control execution flag is reset to “0”, and variable intake valve control is performed. The valve lift amount VL is fixed to the maximum valve lift amount VLmax, and the intake air amount control by the throttle control is executed. At this time, the valve lift amount VL may be fixed to a lift amount other than the maximum valve lift amount VLmax.
[0096]
In this program, when the combustion instability is equal to or greater than the predetermined value K1 (or when the inter-cylinder variation value is equal to or greater than the predetermined value K2), the intake air amount control by the variable intake valve control is prohibited, and the valve lift Although the amount VL is fixed, the intake air amount control by the variable intake valve control is prohibited when the combustion instability is equal to or greater than the predetermined value K1 (or when the inter-cylinder variation value is equal to or greater than the predetermined value K2). Instead, the valve lift amount VL of the variable intake valve control may be guarded with a predetermined guard value, or the variable range of the valve lift amount VL may be narrowed. The variable range of VL may be appropriately limited. At this time, the intake air amount may be controlled by using the variable intake valve control and the throttle control together.
[0097]
[Abnormal diagnosis]
The abnormality diagnosis program shown in FIG. 9 is executed in a predetermined cycle after an ignition switch (not shown) is turned on, and plays a role as an abnormality diagnosis in the claims. When this program is started, first, at step 211, the abnormality determination value K3 is calculated by a map or the like based on the target air amount. Thereafter, in steps 212 and 213, it is determined whether or not the abnormality diagnosis execution condition is satisfied depending on whether or not the following two conditions (1) and (2) are satisfied.
[0098]
(1) The engine speed is within a predetermined range (step 212).
(2) The engine load is within a predetermined range (step 213).
If there is a condition that does not satisfy either of these two conditions (1) and (2), the abnormality diagnosis execution condition is not satisfied, and the program is terminated as it is.
[0099]
On the other hand, if the above two conditions (1) and (2) are satisfied at the same time, the abnormality diagnosis execution condition is satisfied, the process proceeds to the next step 214, and the abnormality determination that the throttle opening degree TA is calculated in step 211 is performed. Whether there is an abnormality in the components of the intake air amount control system is determined based on whether the value is equal to or less than the value K3. As a result, if the throttle opening degree TA is determined to be equal to or less than the abnormality determination value K3, it is determined that there is an abnormality in the components of the intake air amount control system, and the process proceeds to step 215, which means that the abnormality determination flag Xfail is abnormal. Set to “1”, reset the variable intake valve control execution flag to “0”, prohibit the intake air amount control by the variable intake valve control, and fix the valve lift amount VL to the maximum valve lift amount VLmax. Then, abnormal intake air amount control for controlling the intake air amount by throttle control is executed. At this time, the valve lift amount VL may be fixed to a lift amount other than the maximum valve lift amount VLmax.
[0100]
On the other hand, if it is determined in step 214 that the throttle opening degree TA is larger than the abnormality determination value K3, it is determined that there is no abnormality in the components of the intake air amount control system, and the process proceeds to step 216. The determination flag Xfail is reset to “0”, which means no abnormality, and the variable intake valve control execution flag is set to “1” to execute intake air amount control by variable intake valve control.
[0101]
[Abnormal point judgment]
The abnormality location determination program shown in FIG. 10 is executed in a predetermined cycle after an ignition switch (not shown) is turned on, and plays a role as an abnormality diagnosis in the claims together with the abnormality diagnosis program of FIG.
[0102]
When this program is started, first, in step 221, it is determined whether or not the abnormality determination flag Xfail is set to “1” indicating that there is an abnormality, and the abnormality determination flag Xfail is “0” indicating that there is no abnormality. ", The program is terminated without performing the subsequent processing.
[0103]
On the other hand, if the abnormality determination flag Xfail is set to “1” which means that there is an abnormality, the process proceeds to step 222 and whether or not the combustion instability is equal to or less than a predetermined value K4 (or the inter-cylinder variation value). Is less than or equal to a predetermined value K5). Here, the predetermined value K4 (or K5) is a determination value for determining whether or not the variable intake valve lift mechanism 30 has failed, and may be set to an appropriate value through experiments, simulations, or the like.
[0104]
If it is determined in step 222 that the degree of combustion instability is equal to or less than the predetermined value K4 (or the inter-cylinder variation value is equal to or less than the predetermined value K5), the process proceeds to step 223, where a failure of the variable intake valve lift mechanism 30 is detected. judge.
[0105]
On the other hand, if it is determined that the combustion instability is larger than the predetermined value K4 (or the inter-cylinder variation value is larger than the predetermined value K5), the routine proceeds to step 224, where the variable intake valve lift mechanism abnormality diagnosis of FIG. Based on the diagnosis result by the program, it is determined whether or not the variable intake valve lift mechanism 30 is normal. As a result, if it is determined that the variable intake valve lift mechanism 30 is normal, the routine proceeds to step 225, where it is determined that a component other than the variable intake valve lift mechanism 30 has failed. If it is determined that the variable intake valve lift mechanism 30 is not normal, the routine proceeds to step 223, where it is determined that the variable intake valve lift mechanism 30 has failed.
[0106]
[Variable intake valve lift mechanism abnormality diagnosis]
The variable intake valve lift mechanism abnormality diagnosis program shown in FIG. 11 is executed at a predetermined cycle after an ignition switch (not shown) is turned on, and functions as an abnormality diagnosis in the scope of claims together with the programs of FIGS. 9 and 10. Fulfill. In this program, the presence or absence of a failure of the variable intake valve lift mechanism 30 is determined as follows based on the time required for the actual valve lift amount to converge to the target valve lift amount. First, in step 231, it is determined whether or not the amount of change in the target valve lift amount is equal to or less than a predetermined value K6. This program is finished without
[0107]
On the other hand, if it is determined in step 231 that the amount of change in the target valve lift amount is equal to or less than the predetermined value K6, the process proceeds to step 232 and the actual valve lift of the intake valve 28 detected by the lift sensor (not shown). It is determined whether or not the amount has converged to the target valve lift amount within a predetermined time K7. Here, the predetermined time K7 corresponds to the longest time in the normal range of time required for the actual valve lift amount to converge to the target valve lift amount when the change amount of the target valve lift amount is the predetermined value K6. An appropriate value may be set by simulation or the like.
[0108]
If it is determined in step 232 that the actual valve lift amount has converged to the target valve lift amount within the predetermined time K7, the process proceeds to step 233, where it is determined that the variable intake valve lift mechanism 30 is normal. On the other hand, if it is determined that the actual valve lift amount has not converged to the target valve lift amount within the predetermined time K7, the routine proceeds to step 234, where it is determined that the variable intake valve lift mechanism 30 has failed.
[0109]
According to the embodiment (3) described above, when the valve lift amount VL is changed in a state in which the combustion state has deteriorated to some extent due to operating conditions or the like (or in a state in which the variation in intake air amount between cylinders has increased to some extent). If the combustion instability is greater than or equal to the predetermined value K1 in consideration of the possibility that the combustion state will worsen (or the variation in the intake air amount between the cylinders may increase). (When the variation value between the cylinders is equal to or greater than the predetermined value K2), since the valve lift amount VL is fixed, the combustion state has deteriorated to some extent (or the intake air amount variation between cylinders has increased to some extent). By virtue of forcibly changing the valve lift amount VL, the vicious cycle of exacerbating the combustion state (or increasing the variation in intake air amount between cylinders) is avoided. It is possible.
[0110]
Further, during normal operation, in order to reduce the pumping loss and improve the fuel efficiency, the throttle valve opening VL is controlled by varying the valve lift amount VL while the throttle valve 15 is largely opened. In consideration of the fact that the engine is largely open, it is determined whether there is an abnormality in the components of the intake air amount control system depending on whether the throttle opening is equal to or less than the abnormality determination value K3. Therefore, the abnormality diagnosis function can be realized while satisfying the demand for cost reduction without adding new sensors.
[0111]
In addition, when an abnormality is detected in the components of the intake air amount control system, the intake air amount control by the variable intake valve control is prohibited, and the valve lift amount VL is fixed to the maximum valve lift amount VLmax so that the reliability is high. Since the intake air amount control at the time of abnormality that controls the intake air amount by the throttle control is executed, the intake air amount can be controlled with higher accuracy than when the intake air amount control by the variable intake valve control is executed at the time of abnormality detection. Probability is high.
[0112]
During the execution of the abnormal intake air amount control, since the intake air amount is controlled by the throttle control, the instability of combustion is reduced by the abnormal intake air amount control (throttle control) (or the inter-cylinder variation value is reduced). ) Means that a stable combustion state can be obtained by controlling the intake air amount by throttle control (or the variation in intake air amount between cylinders becomes small), and consequently, the intake air amount can be accurately controlled by throttle control. (The drive system / control system of the throttle valve 15 is normal).
[0113]
Considering this point, in the present embodiment (3), whether or not the combustion instability is equal to or less than a predetermined value K4 during execution of the abnormal intake air amount control (or the inter-cylinder variation value is equal to or less than a predetermined value K5). Whether or not the variable intake valve lift mechanism 30 has failed is determined based on whether the variable intake valve lift mechanism 30 is faulty or not, so that the abnormality diagnosis function of the variable intake valve lift mechanism 30 can be reduced at low cost without adding new sensors. It can be realized while satisfying the demands of the system.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an entire engine control system according to an embodiment (1) of the present invention.
FIG. 2 is a front view of a variable valve lift mechanism.
FIG. 3 is a flowchart showing a processing flow of an intake air amount control program according to the embodiment (1).
4A is a diagram conceptually showing a map of a throttle opening learned value GTA, and FIG. 4B is a diagram conceptually showing a map of a valve lift learned value GVL.
FIG. 5 is a time chart showing the behavior of in-cylinder pressure.
FIG. 6 is a flowchart showing a process flow of an intake air amount control program according to the embodiment (2).
FIG. 7 is a time chart showing the behavior of intake pipe pressure.
FIG. 8 is a flowchart showing a flow of processing of a variable intake valve control execution flag set / reset program according to the embodiment (3).
FIG. 9 is a flowchart showing a flow of processing of the abnormality diagnosis program of the embodiment (3).
FIG. 10 is a flowchart showing a flow of processing of an abnormal point determination program according to the embodiment (3).
FIG. 11 is a flowchart showing the flow of processing of a variable intake valve lift mechanism abnormality diagnosis program of the embodiment (3).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Engine (internal combustion engine), 12 ... Intake pipe, 14 ... Air flow meter, 15 ... Throttle valve, 18 ... Intake pipe pressure sensor, 20 ... Fuel injection valve, 21 ... Spark plug, 22 ... Exhaust pipe, 24 ... Air-fuel ratio Sensor 26, crank angle sensor 27, ECU (intake air amount control means, combustion instability detection means, inter-cylinder variation detection means, learning means, control amount restriction means, abnormality determination means) 28, intake valve 29 ... exhaust valve, 30, 31 ... variable valve lift mechanism.

Claims (7)

In a control device for an internal combustion engine having a variable intake valve mechanism capable of controlling an intake air amount by varying a control amount of an intake valve of the internal combustion engine,
An inter-cylinder variation detecting means for detecting an inter-cylinder variation value representing an intake air amount variation between cylinders of the internal combustion engine;
Based on the inter-cylinder variation value, when the inter-cylinder variation value is larger than a predetermined determination value , the control amount of the intake valve is controlled to increase and correct the intake valve valve lift amount by a predetermined amount, and the intake air amount change It controls a control amount of the throttle valve so as to suppress an intake air amount control means for controlling the reduction correction or extender corrected intake air amount of the throttle opening degree,
The inter-cylinder variation detecting means detects the inter-cylinder variation value based on at least one of intake air amount, intake pipe pressure, rotational fluctuation, in-cylinder pressure, ion current, and air-fuel ratio. Control device for internal combustion engine. To claim 1, characterized in that opening of the throttle valve is provided with an abnormality determination means for determining the presence or absence of an abnormality of the components of the intake air amount control system at or less than a predetermined abnormality judgment value The internal combustion engine control device described. The intake air amount control means fixes an intake valve control amount when an abnormality is detected by the abnormality determination means, and controls the intake air amount by controlling the opening of the throttle valve. The control apparatus for an internal combustion engine according to claim 2 , wherein: The abnormality determination unit determines that the variable intake valve mechanism is abnormal when the inter-cylinder variation detection value detected by the inter-cylinder variation detection unit during execution of the abnormal intake air amount control is smaller than a predetermined value. The control device for an internal combustion engine according to claim 3 . The abnormality determining means is configured to operate the variable intake valve mechanism normally when the inter-cylinder variation detection value detected by the inter-cylinder variation detecting means is equal to or greater than a predetermined value during execution of the abnormal intake air amount control. The internal combustion engine according to claim 3 or 4 , wherein if it is determined whether or not the engine is operating normally, it is determined that the drive system / control system of the throttle valve is abnormal. Control device. The abnormality determining means determines whether or not the variable intake valve mechanism is operating normally by comparing an output of a sensor that detects the position of the intake valve and a control amount of the intake valve. The control device for an internal combustion engine according to claim 5 . Learning means for learning the control amount of the intake valve and / or the control amount of the throttle valve set by the intake air amount control means;
The control apparatus for an internal combustion engine according to any one of claims 1 to 6 , wherein the intake air amount control means sets a next control amount based on the control amount learned by the learning means.

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