JP7135434B2 - Control device for internal combustion engine - Google Patents

Description

The present invention relates to a control device for an internal combustion engine.

2. Description of the Related Art An internal combustion engine is known that has a variable valve device that changes the valve timing of an intake valve and an exhaust valve. In such an internal combustion engine, various control values are learned in order to improve the control accuracy of valve timing. Various techniques have been proposed to increase opportunities for learning such control values.

For example, in the technique disclosed in Patent Document 1, a reference phase relating to the valve timing of the intake valve is learned as the control value. The mode for driving is changed to a mode suitable for learning control values. More specifically, when the learning process of the reference phase has not been completed, the reference phase is learned by expanding the engine operating region in which the reference phase is set as the target phase of the intake valves from the region during normal operation. I am trying to create more opportunities.

JP 2012-41901 A

By the way, when changing the setting mode of the valve timing from the mode for normal operation to the mode suitable for learning the control value, when the learning of the control value is completed, the setting mode of the valve timing is returned to the mode for normal operation. Become. Here, when the valve timing of the intake valve changes due to such switching of the setting mode, the intake air amount changes suddenly, and the output torque of the internal combustion engine changes, which may cause a torque shock.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control system for an internal combustion engine that can suppress the occurrence of torque shock after learning of control values for a variable valve gear is completed. That's what it is.

A control device for an internal combustion engine that solves the above problems is applied to an internal combustion engine that has a variable valve device that changes the valve timing of an intake valve through the operation of a duty-controlled oil control valve. Then, the control device controls the load range of the internal combustion engine determined by the engine speed and the engine load, in which the valve timing is changed according to the engine speed and the engine load . A learning process is executed to learn a holding duty ratio, which is a drive duty ratio of the oil control valve required to hold the valve timing, in the operating region when the variable valve device is in the operating region. Then, when the learning of the holding duty ratio is not completed, the control device executes an enlargement process for enlarging the operating region compared to when the learning of the holding duty ratio is completed. After the learning of the duty ratio is completed, when the amount of intake air becomes equal to or less than a predetermined value, the enlargement process is terminated.

In this configuration, the hold duty ratio required to hold the valve timing of the intake valve is learned in the operation region as the control value for the variable valve device. Here, when the learning of the holding duty ratio is not completed, the operating region is expanded compared to when the learning of the holding duty ratio is completed . It can be performed in a wider range , which increases the chances of learning the holding duty ratio. Further, after completion of learning of the holding duty ratio, when the intake air amount becomes a low air amount state of a predetermined value or less, the expansion process is ended. Even if the valve timing of the intake valve changes due to the termination of this expansion process, the change in the valve timing does not change the output torque of the internal combustion engine at this time because the intake air quantity is in a low air quantity state. Therefore, according to this configuration, it is possible to suppress the occurrence of a torque shock after the learning of the holding duty ratio is completed. It should be noted that it is preferable that the predetermined value is an intake air amount that is within a range in which the change in the output torque of the internal combustion engine can be tolerated even if the valve timing of the intake valve changes.

1 is a schematic diagram showing an internal combustion engine and a control device according to one embodiment; FIG. FIG. 4 is a conceptual diagram showing a map mode for setting the intake target phase in the same embodiment; 4 is a flowchart showing a processing procedure for setting a learning promotion flag in the same embodiment; 4 is a flowchart showing a processing procedure for switching the intake target phase calculation map in the same embodiment; 4 is a timing chart for explaining the operation of the same embodiment;

An embodiment embodying a control device for an internal combustion engine will be described below with reference to FIGS. 1 to 5. FIG.
As shown in FIG. 1, in the internal combustion engine 1, air is drawn into the combustion chamber 2 through an intake passage 3 and an intake port 3a, and fuel injected from a fuel injection valve 4 is supplied to the combustion chamber 2. When a mixture of air and fuel is ignited by the ignition plug 5, the mixture burns, causing the piston 6 to reciprocate and the crankshaft 7, which is the output shaft of the internal combustion engine 1, to rotate. The air-fuel mixture after combustion is discharged from the combustion chamber 2 to the exhaust passage 8 as exhaust.

An intake passage 3 of the internal combustion engine 1 is provided with a throttle valve 29 for adjusting the amount of intake air. The opening of the throttle valve 29 is adjusted by an electric motor.
An intake port 3a connected to the intake passage 3 is provided with an intake valve 9. As shown in FIG. An exhaust port 8 a connected to the exhaust passage 8 is provided with an exhaust valve 10 . These intake valves 9 and exhaust valves 10 are respectively opened and closed according to the rotation of the intake side camshaft 11 and the exhaust side camshaft 12 to which the rotation of the crankshaft 7 is transmitted.

The intake side camshaft 11 is provided with a hydraulic vane type intake variable valve device 13 that changes the valve timing (opening/closing timing) of the intake valves 9 by changing the relative phase of the intake side camshaft 11 with respect to the crankshaft 7 . is provided. Note that the relative phase of the intake side camshaft 11 with respect to the crankshaft 7 is hereinafter referred to as an intake valve phase.

This intake-side variable valve device 13 is a well-known device that changes the intake valve phase through the operation of an intake-side oil control valve 14 that is duty-controlled. It has The intake side oil control valve 14 is a well-known linear solenoid valve. Controls the lubricating oil supply to the retarding oil chamber. When lubricating oil is supplied to the advance oil chamber through the operation of the intake side oil control valve 14, the intake valve phase changes to the advance side. Further, when lubricating oil is supplied to the retarded angle oil chamber through the operation of the intake side oil control valve 14, the intake valve phase changes to the retarded angle side. When the supply of lubricating oil to the advance oil chamber and the retard oil chamber is cut off through the operation of the intake side oil control valve 14, the intake valve phase is held at the phase at the time of cutoff.

Further, the intake side variable valve device 13 is controlled in such a manner that the intake side oil control valve 14 is not operated, that is, when the intake side oil control valve 14 is prohibited from being energized, a predetermined The valve timing of the intake valve 9 is maintained so as to achieve the specified timing. In this embodiment, when the intake side oil control valve 14 is not operated, the spool valve is returned to the initial position by the biasing force of the spring, thereby supplying lubricating oil to the retarded angle oil chamber of the intake side variable valve device 13. It's like As a result, the specified timing of the intake valve 9 is the most retarded valve timing within the changeable range of the valve timing of the intake valve 9 .

Similarly, the exhaust-side camshaft 12 is provided with a hydraulic vane type exhaust-side variable valve that changes the valve timing (opening/closing timing) of the exhaust valve 10 by changing the relative phase of the exhaust-side camshaft 12 with respect to the crankshaft 7 . A device 16 is provided. Note that the relative phase of the exhaust-side camshaft 12 with respect to the crankshaft 7 is hereinafter referred to as an exhaust valve phase.

This exhaust-side variable valve device 16 is also a well-known device that changes the exhaust valve phase through the operation of an exhaust-side oil control valve 17 whose duty is controlled. It has The exhaust-side oil control valve 17 is also a well-known linear solenoid valve. Controls the lubricating oil supply to the retarding oil chamber. When lubricating oil is supplied to the advance oil chamber through the operation of the exhaust side oil control valve 17, the exhaust valve phase changes to the advance side. Further, when lubricating oil is supplied to the retarded angle oil chamber through the operation of the exhaust side oil control valve 17, the exhaust valve phase changes to the retarded angle side. When the supply of lubricating oil to the advance oil chamber and the retard oil chamber is cut off through the operation of the exhaust side oil control valve 17, the exhaust valve phase is held at the phase at the time of cutoff.

Further, the exhaust side variable valve device 16 is controlled in such a manner that the exhaust side oil control valve 17 is not operated, that is, when the exhaust side oil control valve 17 is prohibited from being energized. The valve timing of the exhaust valve 10 is maintained so as to achieve the specified timing. In this embodiment, when the exhaust side oil control valve 17 is not operated, the spool valve is returned to the initial position by the biasing force of the spring, thereby supplying lubricating oil to the advance oil chamber of the exhaust side variable valve device 16. It's like As a result, the specified timing of the exhaust valve 10 is the most advanced valve timing within the range of change of the valve timing of the exhaust valve 10 .

The control device 100 performs various controls of the internal combustion engine 1 by controlling the throttle valve 29, the fuel injection valve 4, the spark plug 5, the intake side variable valve device 13, the exhaust side variable valve device 16, and the like. The control device 100 includes a CPU 120 and a memory 130 composed of a ROM and a RAM.

When performing various controls, the control device 100 detects the amount of intake air GA detected by the airflow meter 31, the throttle opening TA that is the opening of the throttle valve 29 detected by the throttle sensor 30, and the water temperature sensor 33. The detected cooling water temperature THW and the engine rotation speed NE calculated from the output signal Scr of the crank angle sensor 34 are referred to. The control device 100 also controls the output signal Scai of the intake cam angle sensor 35 that detects the rotation angle of the intake camshaft 11 and the output signal Scai of the exhaust cam angle sensor 36 that detects the rotation angle of the exhaust camshaft 12. See Scae. The control device 100 also refers to an output signal of an accelerator position sensor 28 that detects an operation amount (accelerator operation amount ACCP) of an accelerator pedal 27 operated by a driver of a vehicle equipped with the internal combustion engine 1 .

The control device 100 selects one of a plurality of prepared intake target phase calculation maps for valve timing control of the intake valve 9, and calculates the target value of the intake valve phase based on the engine speed NE, the engine load KL, and the like. is calculated as the intake target phase VTpi.

In this embodiment, an idle map, a normal map, an output priority map, and a learning map are prepared as intake target phase calculation maps.
The idle map is a map selected when the engine operating state is the idle state. In the idling state, the engine rotation speed NE, the engine load KL, etc. are substantially constant. Therefore, when this idle map is selected, the intake target phase VTpi is set to a constant value. In this embodiment, the target intake phase VTpi in the idling state is set to the most retarded phase of the intake valve phase, that is, the most retarded phase. At this time, the intake oil control valve 14 is not operated. Its energization state is controlled as follows.

The normal map is a map selected during normal operation in which the internal combustion engine 1 is operated in a normal operating range (an operating range in which the engine speed is higher than the idling speed). Here, when the load region of the internal combustion engine in which the valve timing of the intake valve 9 is varied according to the engine speed NE and the engine load KL is defined as the operation region of the intake side variable valve device 13, this The operating region in the normal map is indicated by solid lines in FIG.

In FIG. 2, the area surrounded by solid lines is the operating area of the normal map. In this normal map, the operating region is set in the high load region, and the valve timing of the intake valve 9 is variously changed during the high load operating state. On the other hand, in the engine operating region outside the operating region, the most retarded phase of the intake valve phase is set as the intake target phase VTpi, and the intake side oil control valve 14 is controlled so as not to operate.

The output priority map is a map that is selected when an acceleration request or the like is generated. Also, the intake target phase VTpi is set based on the engine load KL and the like. Note that the learning map will be described later.

After calculating the intake target phase VTpi in this manner, the control device 100 calculates the actual intake valve phase, which is the actual value of the intake valve phase detected based on the output signal Scr of the crank angle sensor 34 and the output signal Scai of the intake side cam angle sensor 35. The intake side variable valve device 13 is controlled so that the phase VTfi becomes the intake target phase VTpi. In this embodiment, when the intake valve phase is the most retarded phase, that is, the prescribed timing of the intake valve 9 is set to "0", the advance amount of the valve timing from this most retarded phase is By controlling , the valve timing of the intake valve 9 is changed.

Further, as valve timing control of the exhaust valve 10, the control device 100 refers to an exhaust target phase calculation map based on the engine rotation speed NE, the engine load KL, and the like, and calculates an exhaust target phase VTpe, which is a target value of the exhaust valve phase. Calculate Here, the exhaust target phase VTpe is set so that the valve overlap amount of the intake valve 9 and the exhaust valve 10 becomes an appropriate amount according to the purification request of the exhaust gas. For example, when the valve overlap amount increases, the internal EGR amount increases. Atomization is promoted by raising the temperature. Therefore, the combustion state of the air-fuel mixture is improved, and the amount of HC emissions, for example, is reduced. In addition, the amount of HC emissions is reduced by reburning the unburned fuel contained in the residual gas. Therefore, in the present embodiment, when the internal combustion engine 1 is cold-started, an exhaust target phase VTpe that can ensure an appropriate valve overlap amount for suppressing the amount of HC emissions is calculated. Exhaust gas is adjusted so that the actual exhaust phase VTfe, which is the actual value of the exhaust valve phase detected based on the output signal Scr of the crank angle sensor 34 and the output signal Scae of the exhaust cam angle sensor 36, becomes the target exhaust phase VTpe. It controls the side variable valve device 16 . In this embodiment, when the exhaust valve phase is the most advanced phase, that is, the prescribed timing of the exhaust valve 10 is set to "0", the amount of retardation of the valve timing from this most advanced phase is By controlling the valve timing of the exhaust valve 10 is changed.

In addition, the control device 100 sets the holding duty ratio HD, which is the driving duty ratio of the intake side oil control valve 14 required to hold the intake valve phase, to a value in which the engine operating state is within the operating region shown in FIG. Execute the learning process to learn when Since such a learning process is well known, a detailed description thereof will be omitted. Basically, when a state in which the target intake phase VTpi and the actual intake phase VTfi match each other for a predetermined time or longer, the actual intake phase VTfi changes to the target intake phase. can be considered to be held in phase VTpi. Therefore, the drive duty ratio at the point in time when the target intake phase VTpi and the actual intake phase VTfi have been matched for a predetermined time or more is learned as a holding duty ratio HD and stored in the memory 130 .

In addition, until the learning of the hold duty ratio HD is completed, the accuracy of the intake valve phase when holding the intake valve phase is low. There is a possibility that the wrap amount cannot be secured. Therefore, the control device 100 executes prohibition processing to prohibit the exhaust-side variable valve device 16 from changing the valve timing of the exhaust valve 10 until the learning of the holding duty ratio HD is completed. Since the exhaust side oil control valve 17 is controlled so as not to operate while this prohibition process is being executed, the valve timing of the exhaust valve 10 is the most advanced side within the change range, as described above. valve timing is maintained. That is, the exhaust valve phase is maintained at the most advanced phase.

As described above, in the present embodiment, the holding duty ratio HD is learned when the valve timing of the intake valve 9 is varied, that is, within the operating range of the normal map. The operating regions in this normal map are concentrated in high load regions that are rarely used during normal operation. Therefore, in this state, it is not possible to sufficiently secure learning opportunities for the holding duty ratio HD, and the period during which the change of the valve timing of the exhaust valve 10 is prohibited by the prohibition process may become longer.

Therefore, in the present embodiment, the learning map, which is one of the above-described intake target phase calculation maps, is prepared to promote learning of the holding duty ratio HD.
In FIG. 2, the region surrounded by the dashed line is the learning map operating region, and the learning map operating region is expanded to the low load side compared to the normal map operating region. When the learning of the holding duty ratio HD is not completed, the learning map is selected so that the learning of the holding duty ratio HD can be performed in a wider engine operating range, thereby providing an opportunity to learn the holding duty ratio HD. are trying to increase

Further, when the learning of the holding duty ratio HD is completed, the learning map is switched to another map, thereby ending the enlargement processing for enlarging the operating region. If the valve timing of the intake valve 9 changes due to the termination of the enlargement processing by this map switching, the intake air amount suddenly changes and the output torque of the internal combustion engine 1 changes, which may cause a torque shock. Therefore, in the present embodiment, map switching is performed in an appropriate state, thereby suppressing the torque shock from occurring after the learning of the holding duty ratio HD is completed.

The processing for setting the learning acceleration flag SUP, which is operated to select the learning map, and the processing for selecting the intake target phase calculation map will be described below.
FIG. 3 shows a processing procedure for setting the learning promotion flag SUP. The processing shown in FIG. 3 is performed by CPU 120 executing a program stored in memory 130 of control device 100 at predetermined intervals. In the following description, step numbers are represented by numerals prefixed with "S".

When this process is started, the control device 100 determines whether or not the learning completion flag GDV is "OFF" (S100). The learning completion flag GDV is set in a separate process, and the learning completion flag GDV is set to "OFF" until the learning of the holding duty ratio HD is completed. Then, when learning of the holding duty ratio HD is completed through execution of the learning process, the learning completion flag GDV is set to "ON".

In the process of S100, when it is determined that the learning completion flag GDV is "OFF" (S100: YES), the control device 100 determines whether the current intake air amount GA is equal to or less than the predetermined value α. is determined (S110). This predetermined value α is an amount of intake air that is within a permissible range of changes in the output torque of the internal combustion engine 1 even if the valve timing of the intake valve 9 changes. When the state is the idle state, it is determined that the current intake air amount GA is equal to or less than a predetermined value α.

Then, when it is determined that the intake air amount GA is equal to or less than the predetermined value α (S110: YES), the control device 100 sets the learning promotion flag SUP to "OFF" (S120). Terminate the process once. When the learning promotion flag SUP is set to "OFF", a map other than the learning map is selected from among the intake target phase calculation maps.

On the other hand, when it is determined that the intake air amount GA is not equal to or less than the predetermined value α (S110: NO), the control device 100 sets the learning promotion flag SUP to "ON" (S130), Terminate the process once. When the learning promotion flag SUP is set to "ON", the learning map is selected from among the intake target phase calculation maps.

On the other hand, in the process of step S100, when the learning completion flag GDV is "ON" (S100: NO), the controller 100 determines whether the current intake air amount GA is equal to or less than the predetermined value α. It is determined whether or not (S140). The process of step S140 is the same as the process of step S110.

Then, when it is determined that the intake air amount GA is equal to or less than the predetermined value α (S140: YES), the control device 100 sets the learning promotion flag SUP to "OFF" (S150). Terminate the process once.

On the other hand, when it is determined that the intake air amount GA is not equal to or less than the predetermined value α (S140: NO), the control device 100 once terminates this process. Therefore, when a negative determination is made in step S140, the currently set value of the learning promotion flag SUP is maintained as it is.

FIG. 4 shows a processing procedure for selecting the intake target phase calculation map. The processing shown in FIG. 4 is also performed by CPU 120 executing a program stored in memory 130 of control device 100 at predetermined intervals. The processing shown in FIG. 4 is executed when the engine operating state is other than the idle operating state. When the engine operating state is the idle operating state, the idle map is used as described above. The intake target phase VTpi is calculated.

When this process is started, the control device 100 determines whether or not the current throttle opening TA is equal to or less than the first determination value TAL (S200). Based on the fact that the throttle opening TA is equal to or less than the first determination value TAL, the first determination value TAL can accurately determine that the current engine operating state is suitable for use of the normal map. so that the magnitude of its value is set.

Then, when it is determined that the throttle opening degree TA is equal to or less than the first determination value TAL (S200: YES), the control device 100 determines whether or not the current learning promotion flag SUP is "ON". (S210).

When it is determined that the learning promotion flag SUP is "ON" (S210: YES), the control device 100 selects the learning map and calculates the intake target phase VTpi using the learning map. Execute (S230). Then, this process is terminated once.

On the other hand, when it is determined in the process of step S210 that the learning promotion flag SUP is not "ON" (S210: NO), that is, when the learning promotion flag SUP is "OFF", control device 100 selects the normal map and calculates the intake target phase VTpi using the normal map (S240). Then, this process is terminated once.

When it is determined in the process of step S200 that the throttle opening TA exceeds the first determination value TAL (S200: NO), the controller 100 determines that the current throttle opening TA is the second determination value TAH. It is determined whether or not the above is satisfied (S250). The second determination value TAH is set to a value larger than the first determination value TAL, and based on the fact that the throttle opening TA is equal to or greater than the second determination value TAH, the current engine operating state is the output The magnitude of the value is set so that it can be accurately determined that the driving state is suitable for using the priority map.

Then, when it is determined that the throttle opening degree TA is equal to or greater than the second determination value TAH (S250: YES), the control device 100 selects the output priority map and calculates the intake target phase VTpi based on the output priority map. is calculated (S260). Then, this process is terminated once.

On the other hand, when it is determined in the process of step S250 that the throttle opening degree TA is less than the second determination value TAH (S250: NO), the control device 100 controls the normal map and the output priority map. An interpolated value is calculated by an appropriate method, and the calculated interpolated value is set as the target intake phase VTpi (S270), and this process is temporarily terminated.

Next, the operation of this embodiment will be described.
FIG. 5 shows changes in the intake target phase calculation map selected when the throttle opening TA is equal to or less than the first judgment value TAL.

First, when the learning completion flag GDV is set to "OFF" and the engine operating state is in the idle state, the learning promotion flag SUP is set to "OFF" through the series of processes shown in FIG. At the same time, the idle map is selected.

After that, when the engine load increases and the engine operating state changes from the idling state to the normal operating state (the state in which the internal combustion engine 1 is operated in the normal operating region) (time t1), the process of step S110 in FIG. Since the determination is negative, the learning promotion flag SUP is set to "ON" and the learning map is selected. This increases opportunities for learning the holding duty ratio HD in the normal operating state.

After that, at time t2, when the learning of the holding duty ratio HD is completed, the learning completion flag GDV is set to "ON". Here, even if the learning completion flag GDV is "ON" (S100 in FIG. 3: NO), until the intake air amount GA becomes equal to or less than the predetermined value α, that is, in the present embodiment, the engine operating state Since a negative determination is made in the process of S140 shown in FIG. 3 until the transition from the normal operation state to the idle state, the learning promotion flag SUP is kept "ON". Therefore, the learning map is continuously selected after time t2.

After that, at time t3, when the engine operating state changes from the normal operating state to the idle state, the determination in S140 shown in FIG. The calculation map is switched from the learning map to the idle map. Thus, when the intake air amount GA becomes equal to or less than the predetermined value α after the learning of the holding duty ratio HD is completed, the learning promotion flag SUP is changed from "ON" to "OFF". By switching the target phase calculation map from the learning map to another map, the above-described enlargement processing for enlarging the operating region is terminated.

After that, at time t4, when the engine operating state changes from the idling state to the normal operating state, the determination in S140 shown in FIG. 3 is affirmative. to select the normal map. After the learning of the holding duty ratio HD is completed in this way, the normal map is selected instead of the learning map in the normal operating state.

According to this embodiment described above, the following effects can be obtained.
(1) When the learning of the holding duty ratio HD is not completed, the learning map is selected instead of the normal map in the normal operating state. Therefore, when the learning of the holding duty ratio HD is not completed, the operating region of the intake side variable valve device 13 is expanded compared to when the learning of the holding duty ratio HD is completed. Therefore, learning of the holding duty ratio HD can be performed in a wider engine operating range, thereby increasing opportunities for learning the holding duty ratio HD.

(2) After the learning of the holding duty ratio HD is completed, when the intake air amount GA is in a low air amount state with a predetermined value α or less, the intake target phase calculation map is switched from the learning map to another map. The enlargement processing for enlarging the operating area described above is terminated. Even if the valve timing of the intake valve 9 changes due to the termination of this expansion process, the output torque of the internal combustion engine 1 changes little due to the change in the valve timing because the intake air amount is in a low air amount state at this time. Therefore, even if the expansion processing of the operating region is terminated by switching the intake target phase calculation map after the learning of the holding duty ratio HD is completed, the occurrence of torque shock can be suppressed.

(3) Until learning of the holding duty ratio HD is completed, prohibition processing is executed to prohibit the exhaust side variable valve device 16 from changing the valve timing of the exhaust valve 10 . Here, as described above, in the present embodiment, by selecting a learning map and expanding the operating region of the intake side variable valve operating device 13, opportunities for learning the holding duty ratio HD increase. Therefore, there is a high possibility that the learning of the holding duty ratio HD will be completed during engine operation. The prohibition of changing the valve timing of the exhaust valve 10 by the prohibition process is released. Therefore, it becomes possible to control the valve overlap amount immediately after the engine is started, and it is possible to reduce the amount of HC discharged, for example, at the time of cold start.

In addition, this embodiment can be changed and implemented as follows. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
・In the processing of S110 and S140 shown in FIG. 3, it is determined that the current intake air amount GA is equal to or less than the predetermined value α when the current engine operating state is the idling state. However, such determinations may be made in other ways. For example, such a determination may be made based on the throttle opening TA, accelerator operation amount ACCP, intake air amount GA, and the like. When the vehicle is stopped, it is determined that the current intake air amount GA is equal to or less than the predetermined value α. It may be determined that the

- The output priority map may be omitted from among the plurality of prepared intake target phase calculation maps. Also, by adding the set values of the idle map to the normal map, the normal map may also serve as the idle map.

- The exhaust side variable valve device 16 may be omitted. Even in this case, at least the effects described in (1) and (2) above can be obtained.
- The control device 100 is not limited to having the CPU 120 and the memory 130 and executing software processing. For example, a dedicated hardware circuit (such as an ASIC, for example) that processes at least part of the software processing performed in the above embodiments may be provided. That is, the control device 100 may have any one of the following configurations (a) to (c). (a) A processing device that executes all of the above processes according to a program, and a program storage device such as a memory that stores the program. (b) A processing device and a program storage device for executing part of the above processing according to a program, and a dedicated hardware circuit for executing the remaining processing. (c) provide dedicated hardware circuitry to perform all of the above processing; Here, there may be a plurality of software processing circuits including a processing device and a program storage device, or a plurality of dedicated hardware circuits. That is, the processing may be performed by a processing circuit comprising at least one of one or more software processing circuits and one or more dedicated hardware circuits.

Reference Signs List 1 Internal combustion engine 2 Combustion chamber 3 Intake passage 3a Intake port 4 Fuel injection valve 5 Ignition plug 6 Piston 7 Crankshaft 8 Exhaust passage 8a Exhaust port 9: Intake valve 10: Exhaust valve 11: Intake side camshaft 12: Exhaust side camshaft 13: Intake side variable valve device 14: Intake side oil control valve 16: Exhaust side variable valve device 17 Exhaust side oil control valve 27 Accelerator pedal 28 Accelerator position sensor 29 Throttle valve 30 Throttle sensor 31 Air flow meter 33 Water temperature sensor 34 Crank angle sensor 35 Intake cam Angle sensor 36 Exhaust side cam angle sensor 100 Control device 120 CPU 130 Memory.

Claims (1)

Applied to an internal combustion engine equipped with a variable valve gear that changes the valve timing of an intake valve through the operation of a duty-controlled oil control valve ,
A load region of the internal combustion engine determined by the engine speed and the engine load, in which the valve timing is changed according to the engine speed and the engine load, is defined as an operating region of the variable valve gear. a control device for executing a learning process for learning a holding duty ratio, which is a drive duty ratio of the oil control valve required to hold the valve timing, in the operating region when
When the learning of the holding duty ratio is not completed, an expansion process is executed to expand the operating region compared to when the learning of the holding duty ratio is completed, and the learning of the holding duty ratio is completed. A control device for an internal combustion engine that executes a process of ending the expansion process when the intake air amount becomes equal to or less than a predetermined value later.

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