JP2015059528A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine which can reduce a frequency of the execution of re-learning of each learning value while suppressing the repetition of fuel cut by overspeed prevention control.SOLUTION: A control device of an internal combustion engine performs: ISC control; throttle learning control for learning a relationship between a throttle opening and a throttle passage air intake amount; engine friction learning control for learning friction acting on an engine output shaft; and overspeed prevention control for executing a fuel cut when an engine rotation speed reaches a prescribed speed or higher. When the fuel cut in the overspeed prevention control is executed a plurality of times (time t11) during the execution of the ISC control, a throttle characteristic learning value is reset to an initial value. When the execution of the fuel cut is repeated after the reset (time t12), an engine friction learning value is reset to an initial value.

Description

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

  Conventionally, in operation control of an internal combustion engine, idle speed control control (so-called ISC) that adjusts an engine control amount (intake air amount, fuel injection amount, etc.) so that an actual engine rotation speed during idle operation matches a target rotation speed. Control) is being executed.

  In the operation control of the internal combustion engine, learning control for learning various engine parameters is executed in order to execute the various controls precisely in accordance with the engine operation state. As such learning control, the apparatus described in Patent Document 1 executes control (throttle learning control) for learning the relationship between the opening degree of the throttle valve and the amount of air passing through the throttle valve. Further, in the apparatus described in Patent Document 2, as learning control, control for learning the friction acting on the engine output shaft (engine friction learning control) is executed.

  Further, in the operation control of the internal combustion engine, in order to suppress an excessive increase in the engine rotational speed, a so-called fuel that temporarily stops fuel injection to the internal combustion engine when the engine rotational speed exceeds a predetermined speed. It has also been proposed to execute control (over-rotation prevention control) for cutting (see Patent Document 3).

JP 2009-68464 A JP 2008-88942 A JP 2003-343315 A

  Here, factors that cause the fuel cut to be executed by the overspeed prevention control include a value that matches the actual value of the learning value of the throttle learning control (throttle characteristic learning value) and the learning value of the engine friction learning control (engine friction learning value). Is a far-off value. Therefore, if the fuel cut by the overspeed prevention control is executed, if the throttle characteristic learning value and the engine friction learning value are reset to initial values (values suitable for a device having standard operating characteristics), the fuel cut after that It becomes possible to suppress the repetition of. However, when the throttle characteristic learning value and the engine friction learning value are initialized, there arises a problem that these learning values must be learned again.

  The present invention has been made in view of such circumstances, and an object of the present invention is to control an internal combustion engine that can suppress the frequency of re-learning of each learning value while suppressing repetition of fuel cut by over-rotation prevention control. To provide an apparatus.

  An internal combustion engine control apparatus for achieving the above object includes an ISC control for adjusting an engine control amount so that an actual engine rotational speed during idle operation of the internal combustion engine matches a target rotational speed, and an opening degree of a throttle valve. And the throttle learning control that learns the relationship between the amount of intake air that passes through the throttle valve, the engine friction learning control that learns the friction that acts on the engine output shaft, and the engine speed has exceeded a predetermined speed. And an over-rotation prevention control for executing a fuel cut that temporarily stops fuel injection into the internal combustion engine.

  As a result of investigating the cause of the phenomenon that the fuel cut is repeatedly executed by the over-rotation prevention control during the ISC control, the main cause of the occurrence is the replacement or cleaning of the throttle device including the throttle valve and its peripheral part. It was found that this was a change in the operating characteristics of the throttle device.

  In view of this point, in the above control device, when the fuel cut is executed a plurality of times during the execution of the ISC control, the learning value (throttle characteristic learning value) of the throttle learning control is reset to the initial value. Therefore, when the throttle characteristic learning value becomes far from the actual value due to replacement or cleaning of the throttle device, the throttle characteristic learning value is set to the initial value (the value appropriate for the throttle device with standard operating characteristics). ) Can be changed. As a result, the learning value of the throttle characteristic can be brought close to a value suitable for the actual situation, and therefore, subsequent fuel cuts can be suppressed. Further, in this case, since the learning value of the engine friction learning control (engine friction learning value) is not reset to the initial value, compared with a device that resets both the throttle characteristic learning value and the engine friction learning value to the initial value, It is possible to reduce the number of executions of re-learning of learning values and suppress the execution frequency.

  If the fuel cut by over-rotation prevention control is executed immediately after the throttle characteristic learning value is reset to the initial value, the engine friction learning value may be caused by mislearning or the like as the cause of the above phenomenon. It is suspected that the value is far from the actual value.

  In this regard, in the above control device, when the execution of the fuel cut is repeated after the reset of the throttle characteristic learning value, the learning value of the engine friction learning control is reset to the initial value. Therefore, if the engine friction learning value is far from the actual value, the engine friction learning value can be changed to the initial value (a value suitable for an internal combustion engine with standard operating characteristics) As a result, the engine friction learning value can be brought close to a value suitable for the actual situation, and therefore it is possible to suppress repeated fuel cuts thereafter.

  As described above, according to the control device, when a phenomenon in which the fuel cut is repeatedly performed by the overspeed prevention control during the execution of the ISC control, the throttle characteristic learning value is reset preferentially, thereby It is possible to suppress the re-learning frequency of the engine friction learning value while suppressing the repeated cutting.

1 is a schematic diagram showing a schematic configuration of an embodiment of a control device for an internal combustion engine. The flowchart which shows the execution procedure of a reset process. The timing chart which shows an example of the execution aspect of a reset process.

Hereinafter, an embodiment of a control device for an internal combustion engine will be described.
As shown in FIG. 1, a throttle valve 12 is provided in the intake passage 11 of the internal combustion engine 10. A throttle motor 13 is connected to the throttle valve 12. Then, the opening degree of the throttle valve 12 (throttle opening degree TA) is adjusted through the drive control of the throttle motor 13, thereby changing the passage sectional area of the intake passage 11, and the combustion chamber of the internal combustion engine 10 through the intake passage 11. The amount of air sucked into 15 is adjusted. In the present embodiment, a throttle device 14 is formed by integrally forming a part of the intake passage 11 (the peripheral portion of the throttle valve 12), the throttle valve 12, and the throttle motor 13. The internal combustion engine 10 includes a fuel injection valve 16 that injects fuel and supplies the fuel to the combustion chamber 15.

  The internal combustion engine 10 includes various sensors for detecting the operation state. As various sensors, for example, a throttle sensor 21 for detecting the throttle opening degree TA, an intake air amount sensor 22 for detecting the amount of intake air passing through the intake passage 11 (passage intake air amount GA), engine cooling water, and the like. A water temperature sensor 23 for detecting the temperature (cooling water temperature THW) is provided. Further, an accelerator sensor 24 for detecting an operation amount (accelerator operation amount ACC) of an accelerator operation member such as an accelerator pedal, and a rotation speed of the crankshaft 17 (engine rotation speed NE) as an engine output shaft are detected. A crank sensor 25 and an atmospheric pressure sensor 26 for detecting the atmospheric pressure PA are provided. In addition, an operation switch 27 that is turned on when the internal combustion engine 10 is started and turned off when the internal combustion engine 10 is stopped is also provided.

  The internal combustion engine 10 includes an electronic control unit 20 configured with, for example, a microcomputer. The electronic control unit 20 takes in detection signals from various sensors and performs various calculations, and executes various controls related to engine control such as intake air amount adjustment control and fuel injection control based on the calculation results.

Hereinafter, an execution mode of the intake air amount adjustment control will be described.
In the present embodiment, a physical model that models the internal combustion engine 10 is constructed. This physical model includes a physical model that models an intake passage 11 composed of an air cleaner, an intake pipe, a surge tank, an intake manifold, and the like, and an engine intake system that includes a throttle valve 12, an intake valve, etc., a piston, and a connecting rod. , And a physical model that models the engine body including the crankshaft 17 and the like.

  Then, through the physical model, the control target for the throttle opening degree TA at which the in-cylinder intake amount (required in-cylinder intake amount Tkl, which will be described later) matches the actual in-cylinder intake amount through the physical model. A value (target throttle opening degree Tta) is calculated. Specifically, the amount of air passing through the throttle valve 12 (throttle passage intake amount), the engine speed NE, the in-cylinder intake amount, the pressure in the combustion chamber 15 (in-cylinder pressure), the opening of the throttle valve 12, the atmospheric pressure A model equation having PA as a variable is determined in advance, and the target throttle opening degree Tta is calculated through the model equation. Specifically, the required in-cylinder intake air amount Tkl is calculated based on the accelerator operation amount ACC and the engine speed NE. Then, based on the required in-cylinder intake air amount Tkl, the engine speed NE, and the like, the target throttle opening degree Tta is calculated from the model formula.

  Further, in the present embodiment, as one of the processes related to the intake air amount adjustment control, an idle learning process (so-called ISC control) for learning the intake air amount at which a target idle rotation speed is obtained during the idling operation of the internal combustion engine 10 is obtained. Executed. This ISC control is executed as follows.

  That is, first, a control target value (target rotational speed Tne) for the engine rotational speed NE is calculated based on the coolant temperature THW. Here, since the engine combustion state tends to become unstable as the coolant temperature THW is lower, a high speed is set as the target rotation speed Tne to avoid this. Thereafter, a deviation ΔNE (= NE−Tne) between the engine rotational speed NE and the target rotational speed Tne is calculated, and an ISC learning value is calculated based on the deviation ΔNE. Specifically, the ISC learning value is added with a predetermined value when the engine speed NE is lower than the target speed Tne (deviation ΔNE <0), while the engine speed NE is equal to or higher than the target speed Tne. In some cases (deviation ΔNE ≧ 0), a predetermined value is subtracted from the ISC learning value. The ISC learning value is stored in the electronic control unit 20, and the stored value is updated each time the ISC learning value is calculated. In the intake air amount adjustment control, the required in-cylinder intake air amount Tkl is corrected by the ISC learned value so that the ISC learned value is added to the required in-cylinder intake air amount Tkl.

  As described above, in the present embodiment, the required in-cylinder intake amount Tkl is feedback-controlled in accordance with the deviation ΔNE so that the engine rotational speed NE and the target rotational speed Tne during the idling operation of the internal combustion engine 10 coincide with each other. As described above, the ISC control is executed.

  Furthermore, in the present embodiment, throttle learning control for learning the relationship (flow rate characteristics) between the opening degree of the throttle valve 12 and the amount of air passing through the throttle is executed as one of the processes related to the intake air amount adjustment control. This throttle learning control is performed on the condition that the execution condition that the throttle opening degree TA is equal to or greater than the predetermined opening degree and the operation state of the internal combustion engine 10 is a stable operation state with very little change is established. It is executed as follows.

  That is, first, based on the engine rotational speed NE, the throttle opening degree TA, and the atmospheric pressure PA, the cylinder intake air amount (basic cylinder interior) when the throttle device 14 is assumed to have a standard flow characteristic from the above model equation. Intake amount) is calculated. Further, the actual in-cylinder intake amount is calculated from the above model formula based on the passage intake amount GA, the engine rotational speed NE, the throttle opening degree TA, and the atmospheric pressure PA. Then, a value capable of compensating for the deviation between the basic in-cylinder intake air amount and the actual in-cylinder intake air amount is calculated, and the learning value (throttle characteristic learning value) of the throttle learning control is updated based on the same value. And remembered. Note that the learning of the throttle characteristic learning value is executed in such a manner that the throttle characteristic learning value is gradually changed to a value suitable for the actual situation in order to suppress adverse effects due to erroneous learning.

  As the model formula, a model formula is set that can specify the throttle passage intake air amount by the differential pressure between the upstream side and the downstream side of the throttle valve 12 and the throttle opening TA. In view of this point, in the present embodiment, the throttle characteristic learning value is a value that enables the throttle passage intake air amount to be accurately identified based on the differential pressure and the throttle opening degree TA (more specifically, the model equation above) Is calculated and stored.

  The throttle characteristic learning value updated in this way is applied to the model equation. As a result, even if the flow rate characteristic of the throttle device 14 changes due to adhesion of deposits to the throttle valve 12, the model formula can be made to be a formula that matches the actual flow rate characteristic. A value commensurate with the flow rate characteristic can be calculated as the target throttle opening degree Tta.

  Note that the intake air amount through the throttle gradually decreases as the throttle device 14 changes with time, such as deposit adhesion. Therefore, as the throttle device 14 changes with time, the throttle characteristic learning value gradually changes to a value suitable for the throttle device 14 with a small throttle passage intake amount, that is, a value that increases the engine torque. become.

  In the present embodiment, engine friction learning control for learning the friction acting on the crankshaft 17 is executed as one of the processes related to the intake air amount adjustment control. That is, first, an estimated value (estimated engine speed Vne) of the engine speed NE is calculated from the above model formula based on the throttle opening degree TA, the atmospheric pressure PA, and the like. Then, a value capable of compensating for the deviation between the estimated engine speed Vne and the actual engine speed NE is calculated, and a learning value (engine friction learning value) of the engine friction learning control is calculated based on the same value. Updated and remembered. The learning of the engine friction learning value is executed in such a manner that the engine friction learning value is gradually changed to a value suitable for the actual situation in order to suppress adverse effects due to erroneous learning. In the present embodiment, the engine friction learning value is a value that can accurately identify the friction acting on the crankshaft 17 based on the engine rotational speed NE (specifically, the calculation coefficient in the above model equation). Is calculated and stored.

  Note that the friction acting on the crankshaft 17 basically increases gradually as the internal combustion engine 10 and its auxiliary equipment change over time. Therefore, the engine friction learning value gradually changes to a value suitable for the internal combustion engine 10 having a large friction, that is, a value that increases the engine torque, along with the change with time of the internal combustion engine 10 and accessories. It becomes like this.

  As described above, in the present embodiment, the in-cylinder intake air amount is determined based on the ISC learning value learned through ISC control, the throttle characteristic learning value learned through throttle learning control, and the engine friction learning value learned through engine friction learning control. Adjustment control is executed.

  In the present embodiment, as one of the processes related to the fuel injection control, the fuel injection to the internal combustion engine 10 is temporarily stopped when the engine rotational speed NE becomes equal to or higher than a predetermined speed when the ISC control is executed. The over-rotation prevention control for executing the fuel cut is executed.

  In the present embodiment, a speed range that can be taken by the engine speed NE when the operation control of the internal combustion engine 10 is properly executed in the idle operation state and the internal combustion engine 10 is operating properly is obtained in advance. A speed slightly higher than the upper limit of the range is set to the predetermined speed. When the engine speed NE becomes unnecessarily high during the idling operation of the internal combustion engine 10, the fuel cut is executed over a predetermined period (for example, a period in which the crankshaft 17 rotates once) by the overspeed prevention control. The rotational speed NE is reduced, and overheating of the internal combustion engine 10 is suppressed.

  Here, the cause of the fuel cut being executed by the over-rotation prevention control is that the throttle characteristic learning value and engine friction learning are caused by erroneous learning of the throttle characteristic learning value and engine friction learning value, replacement of the throttle device 14, internal cleaning, and the like. The value is far from the value that matches the actual situation. Therefore, when the fuel cut is performed, the throttle characteristic learning value and the engine friction learning value are reset to initial values (values suitable for a device having a standard operating characteristic), thereby repeating the fuel cut thereafter. Can be avoided.

  However, if the throttle characteristic learned value and the engine friction learned value are simultaneously reset to the initial values, both the reset of the throttle characteristic learned value and the reset of the engine friction learned value act to reduce the in-cylinder intake amount. Therefore, at this time, the in-cylinder intake amount may be greatly reduced to cause an unnecessary decrease in engine torque, and in some cases, the internal combustion engine 10 may be stalled. Further, when the throttle characteristic learning value and the engine friction learning value are reset, there arises a disadvantage that the learning values must be learned again for each.

  In view of this point, in the present embodiment, by resetting the throttle characteristic learning value and the engine friction learning value at appropriate timings different from each other, it is possible to re-learn each learning value while suppressing repetition of fuel cut by the overspeed prevention control. The frequency of execution is reduced. Hereinafter, a process (reset process) for resetting each learning value to an initial value will be described.

  FIG. 2 shows a specific execution procedure of the reset process. The series of processes shown in the flowchart of FIG. 2 conceptually shows the execution procedure of the reset process, and the actual process is executed by the electronic control unit 20 as an interrupt process at predetermined intervals. .

  As shown in FIG. 2, in this process, first, it is determined whether or not the number of times that the fuel cut by the over-rotation prevention control is executed during the execution of the ISC control is equal to or greater than a predetermined number (“3 times” in this embodiment). Determination is made (step S11). The electronic control unit 20 includes a counter that counts the number of executions of the fuel cut during the execution of the ISC control. The count value of the counter is incremented every time the fuel cut is executed, and is reset to “0” when the count value reaches a predetermined value (“3” in the present embodiment). In the process of step S11, when the count value reaches a predetermined value, it is determined that the number of times that the fuel cut has been executed has become a predetermined number or more.

  In this process, when the number of times of the fuel cut during the execution of the ISC control is less than the predetermined number (step S11: NO), the following processes (steps S12 to S14) are not executed, and the process of step S11 Is repeatedly executed.

  When the number of fuel cuts executed during the execution of the ISC control exceeds the predetermined number (step S11: YES), the throttle characteristic learning value is reset to the initial value (step S12). In the present embodiment, when the throttle characteristic learning value is reset in this manner, the throttle characteristic learning value is maintained until the operation switch 27 is turned off to stop the operation of the internal combustion engine 10 thereafter. The initial value is retained.

  Thereafter, it is determined whether or not fuel cut by over-rotation prevention control is executed in a state where the throttle characteristic learning value is reset to the initial value (step S13). When the fuel cut by the overspeed prevention control is not executed (step S13: NO), the following process (step S14) is not executed and the process of step S13 is repeatedly executed. Thereafter, this process is repeatedly executed, and when the fuel cut by the overspeed prevention control is executed with the throttle characteristic learning value being the initial value (step S13: YES), the engine friction learning value is reset to the initial value. (Step S14).

Hereinafter, an effect of executing such a reset process will be described with reference to FIG.
As a result of the inventor investigating the cause of the occurrence of the phenomenon that the fuel cut is repeatedly executed by the overspeed prevention control during the execution of the ISC control, the main cause of the occurrence is the same as the throttle device 14 is replaced or cleaned. It has been found that the operating characteristics of the are greatly changed. Specifically, when the operating characteristics of the throttle device 14 change greatly due to replacement (or cleaning), the throttle characteristic learning value remains at a value commensurate with the operating characteristics of the throttle device 14 before replacement (or before cleaning). Therefore, the throttle characteristic learning value is far from the value that matches the actual condition (specifically, the operating characteristic of the throttle device 14 after replacement [or after cleaning)). When the internal combustion engine 10 is operated in this state, the engine torque becomes unnecessarily large due to the deviation in the throttle characteristic learning value, and the engine rotational speed NE increases accordingly. The execution of the cut is repeated.

  As shown in FIG. 3, in the reset process, when the fuel cut (FIG. [B]) is executed a predetermined number of times during execution of ISC control (time t11), the throttle characteristic learning value (FIG. [ c)) and the engine friction learning value ([d] in the figure), only the throttle characteristic learning value is reset to an initial value (a value suitable for a throttle device having a standard operating characteristic).

  Thereby, if the situation at this time is a situation where the throttle characteristic learning value is far from the actual value due to replacement or cleaning of the throttle device 14, the throttle characteristic learning value is set to a value appropriate to the actual situation. You can get closer. Therefore, an increase in engine torque due to a deviation in the throttle characteristic learning value is suppressed, and an unnecessary increase in the engine speed NE (FIG. [A]) thereafter, and thus the repetition of the fuel cut are also suppressed. .

  Also, in this case, the engine friction learning value is not reset to the initial value, so compared with a device that simultaneously resets the throttle characteristic learning value and the engine friction learning value to the initial value to suppress repeated fuel cuts due to overspeed prevention control. Thus, the number of executions of relearning of learning values can be reduced and the execution frequency can be suppressed.

  Even if the throttle characteristic learning value is reset to the initial value in this way, the subsequent increase in the engine speed NE cannot be properly suppressed, and the fuel cut by the overspeed prevention control is performed during the execution of the ISC control. May occur repeatedly. In this case, as a cause of occurrence of the above phenomenon, it is suspected that the engine friction learning value is far from the value that matches the actual condition due to erroneous learning or the like.

  In view of this point, in the reset process, when the fuel cut execution by the overspeed prevention control is repeated even though the throttle characteristic learning value is reset (time t12), the engine friction learning value is set to the initial value. The value is reset to (a value suitable for an internal combustion engine with standard operating characteristics). In the reset process, it is determined that the throttle characteristic learning value is reset when the throttle characteristic learning value is the initial value. In addition, it is determined that the fuel cut by the overspeed prevention control has been repeated even though the throttle characteristic learning value has been reset because the fuel cut by the overspeed prevention control has been executed in such a situation (see FIG. 2 (see step S13).

  Therefore, if the situation at this time is a situation where the engine friction learning value is far from the actual value, it is possible to bring the engine friction learning value closer to the actual value. The increase in engine torque due to the deviation of the learning value is suppressed, and the subsequent fuel cut is also suppressed.

  As described above, according to the present embodiment, when a phenomenon occurs in which the fuel cut is repeatedly performed by the overspeed prevention control during the execution of the ISC control, the throttle characteristic learning value is reset preferentially, thereby It is possible to suppress the re-learning frequency of the engine friction learning value while suppressing the repeated cutting.

As described above, according to the present embodiment, the following effects can be obtained.
(1) When the fuel cut in the overspeed prevention control is executed a plurality of times during the execution of the ISC control, the throttle characteristic learning value is reset to the initial value, and after the reset, the fuel cut is repeated. The engine friction learning value was reset to the initial value. Therefore, it is possible to suppress the frequency of re-learning the engine friction learning value while suppressing the fuel cut from being repeated.

The above embodiment may be modified as follows.
The condition for resetting the count value of the counter that counts the number of executions of the fuel cut to “0” is not limited to the condition that “the count value has reached a predetermined value”, but “the operation switch 27 is A condition that “on operation (or off operation) has been performed” and a condition that “execution of ISC control has been started (or stopped)” may be defined.

  When the number of times of fuel cut by over-rotation prevention control during the execution of ISC control reaches a predetermined number, if the throttle characteristic learning value is the initial value, the engine friction learning value is reset to the initial value. It may be. In this case, although the fuel cut is repeated during the execution of the ISC control, since the throttle characteristic learning value is already the initial value, the throttle characteristic learning value is set to the initial value through the reset process (see FIG. 2). By the way, the throttle characteristic learning value does not change at all, and the effect of suppressing the occurrence of the phenomenon of repeating the fuel cut cannot be obtained. In this regard, according to the above apparatus, in such a case, the engine friction learning value can be reset to the initial value without executing the reset of the throttle characteristic learning value, so that the occurrence of the above phenomenon can be suppressed early. Can do.

  In the above embodiment, when the throttle characteristic learning value is reset to the initial value in the reset process (step S12 in FIG. 2), the throttle characteristic learning value is set until the operation switch 27 is turned off thereafter. The initial value was retained. In this case, the throttle characteristic learning value may be learned and updated instead of holding the throttle characteristic learning value as the initial value.

  In the reset process (FIG. 2), when the fuel cut by the overspeed prevention control is executed with the throttle characteristic learning value being the initial value (step S13: YES), the engine friction learning value is reset to the initial value. (Step S14). The conditions for resetting the engine friction learning value can be changed as appropriate as long as it is possible to determine that the fuel cut by the overspeed prevention control has been repeated despite the fact that the throttle characteristic learning value has been reset. it can. As such conditions, for example, the following [Condition A] and [Condition B] can be adopted. [Condition A] After the engine speed NE has started to increase with the stop of the fuel cut by the overspeed prevention control, the engine speed NE has continued to increase and has exceeded a predetermined speed. [Condition B] The fuel cut by the over-rotation prevention control is executed when the execution of the ISC control is continued after the fuel cut by the over-rotation prevention control is stopped.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Intake passage, 12 ... Throttle valve, 13 ... Throttle motor, 14 ... Throttle device, 15 ... Combustion chamber, 16 ... Fuel injection valve, 17 ... Crankshaft, 20 ... Electronic control unit, 21 ... Throttle Sensor: 22 ... Intake amount sensor, 23 ... Water temperature sensor, 24 ... Accelerator sensor, 25 ... Crank sensor, 26 ... Atmospheric pressure sensor.

Claims (1)

The relationship between the ISC control that adjusts the engine control amount so that the actual engine speed during idling of the internal combustion engine matches the target engine speed, and the amount of intake air that passes through the throttle valve Throttle learning control to learn, engine friction learning control to learn the friction that acts on the engine output shaft, and temporarily stop fuel injection to the internal combustion engine when the engine speed exceeds a predetermined speed In the control device for the internal combustion engine that performs the over-rotation prevention control that performs the fuel cut to be performed,
The control device resets the learning value of the throttle learning control to an initial value when the fuel cut is executed a plurality of times during the execution of the ISC control, and the execution of the fuel cut is repeated after the reset. Sometimes, the engine friction learning control learning value is reset to an initial value.