JP6790770B2 - Internal combustion engine control device - Google Patents

Description

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

As a conventional control device for an internal combustion engine, the one described in Patent Document 1 is known. The internal combustion engine control device described in Patent Document 1 includes ISC control that adjusts the engine control amount so that the actual engine rotation speed during idle operation of the internal combustion engine matches the target rotation speed, and throttle valve opening degree. Throttle learning control, which learns the relationship with the amount of intake air passing through the throttle valve, is executed.

In addition, this internal combustion engine control device temporarily performs engine friction learning control that learns the friction acting on the engine output shaft, and fuel injection to the internal combustion engine when the engine rotation speed exceeds a predetermined predetermined speed. The over-rotation prevention control, which executes the fuel cut to stop the internal combustion engine, is executed.

Further, the internal combustion engine control device described in Patent Document 1 resets the learning value of the throttle learning control to the initial value when the fuel cut is executed a plurality of times during the execution of the ISC control, and after the reset, the fuel cut is performed. When the execution is repeated, the learning value of the institutional friction learning control is reset to the initial value.

JP-A-2015-59528

However, in the control device for an internal combustion engine described in Patent Document 1, the initial value of the learned value when resetting prevents engine stall in consideration of friction and the like of each part in an unused state. The decision was made with priority given to this, and it was not set in consideration of aging deterioration due to the use of the internal combustion engine. That is, as compared with the initial production of the internal combustion engine, the friction of each part becomes smaller due to the smoothing of the friction surface and the decrease in the viscosity of the lubricating oil with use.

Therefore, in the control device for the internal combustion engine described in Patent Document 1, when the learning value is reset to the initial value in the state where the friction is reduced, the state in which the engine speed is high continues. In addition, if the engine speed continues to be high, it will take a long time to converge to an appropriate target idle speed.

Therefore, according to the present invention, the internal combustion engine can control the engine speed to an appropriate speed even when the friction is reduced due to use, and can quickly establish the condition for performing ISC learning control. It is intended to provide a control device.

One aspect of the invention of the control device for an internal combustion engine that solves the above problems includes a control unit that controls the engine speed of the internal combustion engine, and the control unit matches the engine speed during idling with the target idle speed. The control device is a control device for an internal combustion engine that sets the throttle opening so as to cause the internal combustion engine to execute ISC learning control that stores the set throttle opening or the air flow rate correlating with the throttle opening as an ISC learning value. If the ISC learning value has not been updated since it was reset to the initial learning value, and the engine rotation speed is greater than or equal to the predetermined engine rotation speed larger than the target idle rotation speed, the initial learning value is reduced and corrected. The suppression control for suppressing the engine rotation speed is started prior to the ISC learning control.

As described above, according to the present invention, the engine speed can be controlled to an appropriate speed even when the friction is reduced due to use, and the condition for performing ISC learning control can be established at an early stage. ..

FIG. 1 is a configuration diagram of a vehicle equipped with a control device for an internal combustion engine according to an embodiment of the present invention. FIG. 2 is a flowchart illustrating the operation of the control device of the internal combustion engine according to the embodiment of the present invention. FIG. 3 is a diagram showing a correction coefficient calculation map of the control device of the internal combustion engine according to the embodiment of the present invention. FIG. 4 is a timing chart illustrating the operation of the control device of the internal combustion engine according to the embodiment of the present invention. FIG. 5 is a diagram showing a throttle opening degree in each state by the operation of the control device of the internal combustion engine according to the embodiment of the present invention.

The control device for an internal combustion engine according to an embodiment of the present invention includes a control unit that controls the engine rotation speed of the internal combustion engine, and the control unit so as to match the engine rotation speed during idling with the target idle rotation speed. It is a control device of an internal combustion engine that sets the throttle opening and stores the set throttle opening or the air flow rate correlating with the set throttle opening as an ISC learning value, and the control unit has an ISC learning value. If the engine speed has not been updated since it was reset to the initial learning value and the engine speed is greater than or equal to the predetermined idling speed, the initial learning value is reduced and corrected to suppress the engine speed. The control is characterized in that the control is started prior to the ISC learning control. As a result, the internal combustion engine control device according to the embodiment of the present invention can control the engine speed to an appropriate speed even when the friction is reduced due to use, and ISC learning control is performed. The conditions to be met can be established at an early stage.

Hereinafter, the control device for the internal combustion engine according to the embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1, a vehicle 1 equipped with a control device for an internal combustion engine according to an embodiment of the present invention includes an internal combustion engine 2 and an ECU (Electronic Control Unit) 3 as a control unit.

The internal combustion engine 2 is composed of a four-cycle engine that performs a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke while the piston makes two reciprocations in the cylinder.

The pistons housed in each cylinder are connected to the crankshaft via a connecting rod. The connecting rod is designed to convert the reciprocating motion of the piston into the rotational motion of the crankshaft.

Therefore, the internal combustion engine 2 drives the vehicle 1 by reciprocating the piston by burning the air-fuel mixture in the combustion chamber 25 in the cylinder and rotating the crankshaft via the connecting rod. It is designed to generate driving force.

The intake port of the internal combustion engine 2 is provided with an intake manifold 31 for introducing air into the combustion chamber 25. The intake manifold 31 is connected to an intake pipe 32 for sucking outside air. That is, the intake manifold 31 communicates the intake pipe 32 with the intake port of each cylinder.

The upstream portion of the intake manifold 31 forms a surge tank that temporarily stores air. An intake pressure sensor 27 is provided upstream of the intake manifold 31, and the intake pressure sensor 27 detects the pressure of the intake manifold 31 and transmits a detection signal to the ECU 3.

The intake pipe 32 is provided with a throttle valve 33 for adjusting the intake air amount of the internal combustion engine 2. The throttle valve 33 is configured as an electronically controlled throttle valve, and the throttle opening degree is controlled in response to a command signal from the ECU 3 to adjust the intake air amount of the internal combustion engine 2.

The throttle valve 33 is provided with a throttle opening sensor 28, and the throttle opening sensor 28 detects the opening degree of the throttle valve 33 and transmits a detection signal as a throttle opening to the ECU 3.

When the direction in which the fresh air of the intake pipe 32 is introduced is the intake direction, the air flow sensor 21 is provided on the upstream side in the intake direction from the throttle valve 33. The air flow sensor 21 detects the flow rate of the air flowing into the internal combustion engine 2.

The exhaust port of the internal combustion engine 2 is provided with an exhaust manifold 41 for discharging the exhaust gas generated by the combustion of the air-fuel mixture in the combustion chamber 25 to the outside of the vehicle. The exhaust manifold 41 is connected to the exhaust pipe 42. That is, the exhaust manifold 41 communicates the exhaust pipe 42 with the exhaust port of each cylinder.

The exhaust pipe 42 is provided with a three-way catalyst 43, an air-fuel ratio sensor 44, and an oxygen sensor 45. The three-way catalyst 43 purifies the exhaust gas discharged from the combustion chamber 25 of the internal combustion engine 2, that is, the burnt gas.

Here, when the direction in which the exhaust gas is discharged is the exhaust direction, the air-fuel ratio sensor 44 is provided on the upstream side in the exhaust direction with respect to the three-way catalyst 43. Further, the oxygen sensor 45 is provided on the downstream side in the exhaust direction with respect to the three-way catalyst 43.

The air-fuel ratio sensor 44 and the oxygen sensor 45 detect the oxygen concentration contained in the exhaust gas to detect whether the air-fuel ratio is on the rich side or the lean side with respect to the stoichiometric air-fuel ratio, and transmit a detection signal. It is transmitted to the ECU 3.

The oxygen sensor 45 is an oxygen sensor having an output characteristic in which the output suddenly changes between the rich side and the lean side with respect to the air-fuel ratio with reference to the stoichiometric air-fuel ratio. Further, the air-fuel ratio sensor 44 is a sensor having an output characteristic linear with respect to the oxygen concentration.

The fuel tank 51 stores gasoline as a fuel for the internal combustion engine 2 in a normal pressure state. The gasoline stored in the fuel tank 51 is pumped by the fuel pump 51a and injected into the intake port from the injector 24 provided in the intake port of each cylinder.

The internal combustion engine 2 is provided with a variable valve timing mechanism 26 on the intake side and the exhaust side, respectively, and by controlling the variable valve timing mechanism 26 by the ECU 3, the intake timing, the exhaust timing, and the valve overlap amount can be adjusted. It has become.

A canister 52 that adsorbs evaporative fuel is connected to the fuel tank 51. A purge pipe 53 is connected to the canister 52, and an intake manifold 31 is connected to the end opposite to the canister 52 of the purge pipe 53. The evaporated fuel adsorbed in the canister 52 is introduced into the intake manifold 31 as a purge gas together with air through the purge pipe 53.

The purge pipe 53 is provided with a purge valve 54. The opening and closing of the purge valve 54 is controlled by the ECU 3. The ECU 3 controls the amount of purge gas introduced into the intake manifold 31 by controlling the opening and closing of the purge valve 54.

The ECU 3 is composed of a computer unit including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an input port, and an output port.

The ROM of the ECU 3 stores various control constants, various maps, and the like, as well as a program for causing the computer unit to function as the ECU 3. That is, when the CPU executes the program stored in the ROM, the computer unit functions as the ECU 3.

In addition to the above-mentioned air flow sensor 21, air-fuel ratio sensor 44, and oxygen sensor 45, various sensors such as an accelerator opening sensor 22, an idle switch 29, and a crank angle sensor 23 are connected to the input port of the ECU 3.

The accelerator opening sensor 22 detects the accelerator opening indicating the amount of operation of the accelerator pedal 22A, and transmits a detection signal to the ECU 3. The idle switch 29 transmits an on signal to the ECU 3 when the accelerator pedal 22A is not depressed.

The crank angle sensor 23 detects the rotation angle of the crankshaft of the internal combustion engine 2. The ECU 3 calculates the engine speed (engine rotation speed) of the internal combustion engine 2 based on the detection result input from the crank angle sensor 23.

Further, the ECU 3 is adapted to calculate the amount of intake air (intake air amount) per unit time based on the signal from the airflow sensor 21. On the other hand, various devices such as an injector 24, a throttle valve 33, and a purge valve 54 are connected to the output port of the ECU 3.

The ECU 3 sets the throttle opening degree so that the engine speed during idling of the internal combustion engine 2 matches the target idle speed. Then, the ECU 3 executes ISC learning control that stores and holds the set throttle opening degree as an ISC learning value. The ISC learning value may be an air flow rate having a correlation with the throttle opening instead of the throttle opening.

The operation by the control device of the internal combustion engine according to the present embodiment configured as described above will be described with reference to the flowchart of FIG.

In FIG. 2, the ECU 3 determines whether or not the ISC learning value has been updated from the initial learning value (step S1), and if not, determines whether or not the idle switch 29 is on (step S1). Step S2). If it is determined in step S1 that the ISC learning value has been updated, or if it is determined in step S2 that the idle switch 29 is off, the ECU 3 ends this operation.

When it is determined in step S2 that the idle switch 29 is on, the ECU 3 determines whether or not the engine speed is equal to or higher than the predetermined engine speed (step S3), and if it is equal to or higher than the predetermined engine speed, The weight loss correction coefficient is determined (step S4), and the initial learning value is weight loss corrected by multiplying the weight loss correction coefficient by the initial learning value (step S5).

The ECU 3 repeats steps S4 and S5 until the engine speed becomes less than the predetermined engine speed. Steps S4 and S5 constitute the suppression control in the present invention. The suppression control for reducing and correcting the initial learning value to suppress the engine speed is continued until it is completed by step S9 described later.

When it is determined in step S3 that the engine speed is less than the predetermined engine speed, the ECU 3 repeats the determination of whether or not the learning condition capable of starting ISC learning is satisfied (step S6). There are a plurality of learning conditions for each of a plurality of ISC learning values that differ depending on the vehicle state.

For example, there are learning conditions corresponding to a cold state where the cooling water temperature is low and a warm-up completion state where the cooling water temperature is high. In addition, there are learning conditions for each operating area of the internal combustion engine (engine speed, engine load, torque, etc.). In addition, there are learning conditions for each transmission stage or gear ratio, and whether or not auxiliary equipment such as an air conditioner is operated.

When the learning condition is satisfied in step S6, the ECU 3 permits the first ISC learning control, that is, the first learning (step S7).

Following step S7, the ECU 3 repeatedly determines whether or not the ISC learning is completed (step S8), and when the ISC learning is completed, ends the weight loss correction of the initial learning value (step S9), and the flowchart of FIG. To finish.

It should be noted that in step S2, whether or not the idle switch 29 is turned on is determined by the driver when it is determined in step S3 that the engine speed is equal to or higher than the predetermined engine speed. This is to distinguish whether or not it is due to a request (accelerator pedal operation).

Further, the predetermined engine speed used as the threshold value in step S3 is preferably set based on the vehicle state. For example, when the shift range is a running range such as R (reverse) range or D (forward) range, the predetermined engine speed is set to a low value, and the shift range is P (parking) range or N (neutral) range. In the non-traveling range, the predetermined engine speed may be set to a high value.

Further, in step S3, instead of comparing the engine speed with the predetermined engine speed, the difference rotation between the actual engine speed and the target speed may be compared with the predetermined threshold. However, in this case, if the target rotation speed suddenly changes due to a change in the operating state of the auxiliary machine or the like, the difference rotation between the target rotation speed and the engine rotation speed also suddenly changes. Therefore, it is desirable to control the engine speed so that the engine speed can be converged without being affected by such a sudden change.

FIG. 3 is a map referred to when calculating the weight loss correction coefficient in step S4 of FIG. This map is obtained in advance by an experiment or the like and is stored in the ECU 3.

In this map, the correlation between the weight loss correction coefficient and the engine speed is defined. In the region where the engine speed is less than the predetermined engine speed, the weight loss correction coefficient is 1.0 (without weight loss correction) and the engine speed. However, in the region where the engine speed is equal to or higher than the predetermined engine speed, the weight loss correction coefficient is set to decrease as the engine speed increases. In other words, as the engine speed increases, the amount of correction for reducing and correcting the initial learning value increases.

The operation of FIG. 2 will be described with reference to the timing chart of FIG. This timing chart shows the state change after the internal combustion engine 2 is started in the state where the ISC learning value is not updated after being reset to the initial learning value.

More specifically, this timing chart shows the time course of the engine speed, the suppression control flag, and the learning permission flag. Here, the suppression control flag is established when it is determined in step S3 of the flowchart of FIG. 2 that the engine speed is equal to or higher than the predetermined engine speed. Further, the learning permission flag is set when it is determined in step S6 of the flowchart of FIG. 2 that the learning condition is satisfied and the first learning is permitted in step S7.

At time t1, the engine speed increases as shown by the solid line due to the input of disturbance such as the load of the auxiliary machine. After that, at time t2, when the engine speed rises above the predetermined engine speed, the suppression control flag is established and the suppression control is started.

In this suppression control, the engine speed is suppressed by the reduction correction for the ISC learning value. As a result, the engine speed converges to the target engine speed, and the learning permission flag is established at time t3. In this timing chart, the case where the disturbance such as the load of the auxiliary machine is not input and the engine speed does not increase significantly is shown by the broken line.

FIG. 5 shows an example of the throttle opening in each state related to the ISC learning value. The vertical axis of FIG. 5 is the throttle opening, and the horizontal axis is the state after learning the ISC learning value, the state after resetting the ISC learning value to the initial learning value (before learning), and after executing the suppression control from the left. It is in the state of.

Further, each state indicates a case where the air conditioner is operating and the shift range is the D range. The vertical axis may be an air flow rate having a correlation with the throttle opening instead of the throttle opening.

In FIG. 5, after learning the ISC learning value, the learning value, the correction amount for the A / C correction due to the operation of the air conditioner, and the correction amount for the D range correction due to the shift range being the D range. The sum of and is the throttle opening.

After resetting to the initial learning value (before learning), the sum of the initial learning value, the correction amount for the A / C correction, and the correction amount for the D range correction is the throttle opening degree. After the suppression control is executed, the sum of the initial learning value corrected for weight loss, the correction amount for A / C correction, and the correction amount for D range correction becomes the throttle opening.

The initial learning value is larger than the idle speed, which is excellent in fuel efficiency and quietness, in order to prevent stall in a state of high friction when the internal combustion engine 2 is first started after being produced in the factory. .. Therefore, the ISC learning value obtained by learning becomes a value smaller than the initial learning value.

Here, when the ISC learning value is reset to the initial learning value, the first learning is performed on condition that the engine speed is stable. Therefore, before the engine speed has converged, the initial learning has not been performed, and the initial learning value has not been updated.

Therefore, in this embodiment, if the engine speed does not converge in a state where the ISC learning value has not been updated since it was reset to the initial learning value, the initial learning value is multiplied by the weight loss correction coefficient to correct the weight loss. By performing control using the initial learning value, the engine speed is converged so that the initial learning can be performed at an early stage.

As described above, in the present embodiment, the ECU 3 sets the throttle opening so that the engine speed during idling matches the target idle speed, and sets the set throttle opening or the air flow rate correlating with the set throttle opening to the ISC. ISC learning control to be stored as a learning value is executed.

Then, when the ISC learning value has not been updated since the ISC learning value was reset to the initial learning value and the engine speed is greater than or equal to the predetermined engine speed larger than the target idle speed, the ECU 3 reduces the initial learning value. Then, the suppression control for suppressing the engine speed is started prior to the ISC learning control.

According to this embodiment, since the initial learning value is reduced and corrected to suppress the engine speed, the engine speed can be appropriately suppressed without being affected by the driving state of the auxiliary machine or the like. That is, since the engine speed is not suppressed by an excessive correction amount considering the load of the auxiliary machine, the engine speed is controlled to an appropriate speed without the internal combustion engine 2 stalling due to the excessive correction amount. it can. Further, by suppressing the engine speed, the condition for performing ISC learning control can be satisfied at an early stage.

As a result, even if the friction is reduced with use, the engine speed can be controlled to an appropriate speed, and the condition for performing ISC learning control can be satisfied at an early stage.

Further, in the present embodiment, the ECU 3 increases the correction amount for reducing and correcting the initial learning value as the engine speed increases.

According to this embodiment, as the engine speed increases, the initial learning value is reduced and corrected with a larger correction amount, so that the engine speed can be quickly converged.

Further, in this embodiment, the ECU 3 ends the suppression control when a predetermined correction end condition is satisfied. The correction end condition is either that the engine speed converges to the target idle speed or that the ISC learning value is updated.

According to this embodiment, the suppression control is continued until either the engine speed converges to the target idle speed or the ISC learning value is updated, so that the ISC learning control is performed. The conditions to be performed can be satisfied at an early stage, and the ISC learning value can be reliably updated by the ISC learning control.

Further, in this embodiment, the ECU 3 sets a predetermined engine speed based on the vehicle state.

According to this embodiment, the condition for performing the ISC learning control can be satisfied at an early stage for all the ISC learning values for each vehicle state.

Although the embodiments of the present invention have been disclosed, it is clear that some skilled in the art can make changes without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the following claims.

2 Internal combustion engine 3 ECU (control unit)

Claims (4)

Equipped with a control unit that controls the engine speed of the internal combustion engine
The control unit
The throttle opening is set so that the engine speed during idling matches the target idle speed, and ISC learning control is executed to store the set throttle opening or the air flow rate correlating with the set throttle opening as an ISC learning value. It is a control device for an internal combustion engine.
The control unit
When the ISC learning value has not been updated since it was reset to the initial learning value, and the engine speed is greater than or equal to the predetermined engine speed greater than the target idle speed.
A control device for an internal combustion engine, characterized in that suppression control for suppressing the engine speed by reducing the initial learning value is started prior to the ISC learning control. The control unit
The control device for an internal combustion engine according to claim 1, wherein the correction amount for reducing and correcting the initial learning value is increased as the engine speed is increased. The control unit
When the predetermined correction end condition is satisfied, the suppression control is terminated, and the suppression control is terminated.
Claim 1 or claim that the correction end condition is either that the engine speed converges to the target idle speed or that the ISC learning value is updated. 2. The control device for an internal combustion engine according to 2. The control unit
The control device for an internal combustion engine according to any one of claims 1 to 3, wherein the predetermined engine speed is set based on a vehicle state.

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