JPH09170476A - Idle rotational speed adjusting device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress occurrence of engine stalling due to insufficient air amount when an idle rotational speed is adjusted. SOLUTION: A main bypass passage 22 and an auxiliary bypass passage 24 through which the upstream and downstream sides of a throttle valve 19 are communicated with each other, are arranged in the inlet passage 11 of an engine 1 by being bypassed the throttle valve 19, and an idle speed control valve (ISCV) 23 and an idle adjusting screw 25 adjusted from the outside are arranged on the way of the main bypass passage 22 and the auxiliary bypass passage 24. In the case that the screw 25 is adjusted from the outside when an idle rotational speed is adjusted, an electronic controller (ECU) 51 fixedly controls the opening of the ISCV 23 at a predetermined opening. Fixing control is executed on the basis of a final duty ratio set on the basis of a leaning value when the ISCV 23 is controlled just before the fixing control. Therefore, an enough air flow corresponding to sludge accumulation can be secured even though sludge is secularly accumulated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine idle speed control device, and more particularly, to an idle speed control device having a main bypass passage and an auxiliary bypass passage bypassing a throttle valve. The present invention relates to an idle speed adjusting device for an internal combustion engine, which has a valve and an adjusting mechanism in the middle of an auxiliary bypass passage.

[0002]

2. Description of the Related Art Generally, in an engine idle speed control system, an idle speed control valve (ISCV) is provided in the middle of a bypass passage provided to bypass a throttle valve in addition to an intake passage. By adjusting the opening of the ISCV, the intake air amount of the internal combustion engine is controlled independently of the throttle valve, and the idle speed is controlled.

In an idle speed control system using this kind of technique, a target speed is set during idling, and a learning opening degree of ISCV is calculated according to an operating state of the engine. Then, the opening degree of the ISCV is feedback-controlled so that the actual engine speed becomes the target speed. As a result, the flow rate of air passing through the bypass passage is controlled, and thus the engine speed during idling is controlled.

In the above technique, the idle speed is adjusted appropriately. That is, an auxiliary bypass passage is separately provided in parallel with the bypass passage, and an idle adjusting screw is provided in the auxiliary bypass passage. Then, by manually adjusting the adjusting screw, the air flow rate in the auxiliary bypass passage is adjusted, and thus the idle speed is adjusted.

By the way, for example, Japanese Patent Publication No. 63-16578.
In the technique disclosed in the publication, the ISCV is fixed at a predetermined opening when adjusting the adjusting screw. Thus, by fixing the ISCV to a predetermined opening, workability in adjustment work can be improved.

[0006]

However, in the above-mentioned prior art, blowback of EGR gas and gas from the combustion chamber,
Alternatively, blow-by gas may cause sludge to accumulate in the bypass passage over time. When the sludge is accumulated in this way, when the adjusting screw is adjusted, the opening of the ISCV is fixed to a uniformly set predetermined opening, so that the air amount required for idle operation is sufficient. There was a risk that it could not be secured. As a result, inconvenience such as engine stall may occur.

The present invention has been made in view of the above circumstances, and an object thereof is to have a main bypass passage and an auxiliary bypass passage bypassing a throttle valve, and an idle speed control valve in the middle of the main bypass passage. Provided is an internal combustion engine having an adjusting mechanism in the middle of an auxiliary bypass passage. When adjusting the idle speed, an idle speed adjusting device for an internal combustion engine capable of suppressing the occurrence of engine stall due to insufficient air amount is provided. To do.

[0008]

In order to achieve the above object, in the present invention, as shown in FIG.
Throttle valve M provided in the middle of the intake passage M2
3, a main bypass passage M4 provided so as to bypass the throttle valve M3, an auxiliary bypass passage M5 similarly provided so as to bypass the throttle valve M3, and a middle portion of the main bypass passage M4. An idle speed control valve M6, which is provided and adjusts the air flow rate in the passage M4 by opening and closing, and an operating state detecting means M7 that detects the operating state of the internal combustion engine M1.
And at least during idling of the internal combustion engine M1, based on the detection result of the operating state detection means M7,
Feedback control means M8 for calculating the learning opening of the idle speed control valve M6 and feedback-controlling the opening of the valve M6 based on the learning opening, and provided in the middle of the auxiliary bypass passage M5,
When adjusting the rotational speed of the internal combustion engine M1 during idling, the adjusting mechanism M9 is adjusted from the outside to adjust the air flow rate of the auxiliary bypass passage M5.
And an adjustment-time fixed control means M10 for performing fixed control of the idle speed control valve M6 at a predetermined opening when the number of revolutions of the internal combustion engine M1 during idling is adjusted by the adjustment mechanism M9. In the idle speed adjusting device, the predetermined opening degree of the idle speed control valve M6, which can be fixedly controlled by the adjustment-time fixing control means M10 during adjustment of the adjusting mechanism M9, before adjustment of the adjusting mechanism M9, Predetermined opening degree setting means M11 that is set based on the learning value calculated by the feedback control means M8
It is the gist of the establishment.

According to the above arrangement, the intake air amount during operation of the internal combustion engine M1 is adjusted by opening and closing the throttle valve M3 provided in the intake passage M2 of the internal combustion engine M1. By this adjustment, the rotation speed of the internal combustion engine M1 is basically adjusted. Further, a main bypass passage M provided so as to bypass the throttle valve M3
4, an idle speed control valve M6 for adjusting the air flow rate in the passage M4 by opening and closing is provided, and the opening degree of the valve M6 is adjusted,
The intake air amount during idling, and thus the rotation speed, is adjusted. That is, the operating state detecting means M7 detects the operating state of the internal combustion engine M1, and at least the internal combustion engine M
Based on the detection result when idling 1
The feedback control means M8 calculates the learning opening degree of the idle speed control valve M6, and feedback-controls the opening degree of the valve M6 based on the learning opening degree.

Further, an adjusting mechanism M9 is provided in the middle of an auxiliary bypass passage M5 provided so as to bypass the throttle valve M3, and this adjusting mechanism is used when adjusting the rotational speed of the internal combustion engine M1 during idling. M
9 is adjusted from the outside. By this adjustment, the air flow rate of the auxiliary bypass passage M5 is adjusted, and by extension, the idling speed is adjusted. Here, when the rotational speed of the internal combustion engine M1 during idling is adjusted by the adjusting mechanism M9, the idling speed control valve M6 is fixedly controlled at a predetermined opening degree by the fixed control means during adjustment M10. By this fixed control, a predetermined amount of air is introduced into the internal combustion engine M1, so that the workability of adjustment work is improved.

In the present invention, at the time of adjusting the adjusting mechanism M9, fixed control is performed by the adjusting-time fixed control means M10 based on the learned value calculated by the feedback control means M8 before the adjustment of the adjusting mechanism M9. The predetermined opening degree of the idle speed control valve M6 that can be set is set by the predetermined opening setting means M11. Therefore, even if sludge is accumulated in the main bypass passage M4, the predetermined opening degree is set based on the learning value at the time of feedback control in consideration of the air flow, which corresponds to the accumulation. Therefore, a sufficient air flow rate is secured when adjusting the adjusting mechanism M9.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which an idle speed adjusting device for an internal combustion engine according to the present invention is embodied in a gasoline engine will now be described in detail with reference to the drawings.

FIG. 2 is a schematic configuration diagram showing an idle speed adjusting device of the engine 1 as an internal combustion engine in the present embodiment. An engine 1 mounted on an automobile has a plurality of cylinders, and a cylinder block 2 that constitutes the engine 1
There are formed cylinder bores 3 for the number of cylinders. A cylinder head 4 is mounted on the upper side of the cylinder block 2 so as to close each cylinder bore 3. A piston 5 is provided in each cylinder bore 3 so as to be vertically movable, and the piston 5 is connected to a crankshaft (not shown) via a connecting rod 6. And the cylinder bore 3
Inside, the space surrounded by the piston 5 and the cylinder head 4 is the combustion chamber 7. Further, lubricating oil in an oil pan (not shown) is supplied to the respective parts such as the cylinder bore 3 and the connecting rod 6 during operation of the engine 1.

The cylinder head 4 is provided with spark plugs 8 corresponding to the respective combustion chambers 7. Also,
The cylinder head 4 is provided with an intake port 9 and an exhaust port 10 communicating with each combustion chamber 7, respectively. An intake passage 11 and an exhaust passage 12 are connected to each of the ports 9, 10, respectively. Furthermore, the intake port 9
An opening / closing intake valve 13 and an exhaust valve 14 are provided at each open end of the exhaust port 10 communicating with the combustion chamber 7. The intake valve 13 and the exhaust valve 14 are opened and closed in conjunction with the rotation of a crankshaft by a valve train including a camshaft (not shown). The opening and closing timings of these valves 13 and 14 are opened and closed in synchronization with the rotation of the crankshaft. That is, each of the valves 13 and 14 is adapted to be opened and closed at a predetermined timing in synchronization with a series of strokes of an intake stroke, a compression stroke, an explosion / expansion stroke and an exhaust stroke.

An air cleaner 1 is provided on the inlet side of the intake passage 11.
5 are provided. In the middle of the intake passage 11,
A surge tank 16 for smoothing the pulsation of the air passing through the passage 11 is provided. Further, on the downstream side of the surge tank 16, near the intake port 9 for each cylinder, an injector 17 for fuel injection is provided. Fuel of a predetermined pressure is supplied to these injectors 17 from a fuel tank (not shown) by a fuel pump. On the other hand, on the outlet side of the exhaust passage 12, a catalytic converter 18 having a built-in three-way catalyst for purifying exhaust gas is provided.

The engine 1 has an air cleaner 15
Is taken in through the intake passage 11 including the surge tank 16. Further, when fuel is injected from each injector 17 simultaneously with the introduction of the outside air, a mixture of the outside air and the fuel is taken into the combustion chamber 7 in synchronization with the opening of the intake valve 13 in the intake stroke. Further, when the air-fuel mixture taken into the combustion chamber 7 is ignited by the spark plug 8, the air-fuel mixture explodes and burns, so that the engine 1 can obtain a driving force. The exhaust gas after the explosion and combustion is guided to the exhaust passage 12 in synchronization with the opening of the exhaust valve 14 in the exhaust stroke, and is discharged from the exhaust passage 12 to the outside through the catalytic converter 18 and the like.

On the upstream side of the surge tank 16, there is provided a throttle valve 19 which opens and closes in conjunction with the operation of an accelerator pedal (not shown). Then, by opening and closing the throttle valve 19, the intake amount of outside air into the intake passage 11, that is, the intake air amount is adjusted.

A throttle sensor 31 for detecting the opening of the valve 19, that is, the throttle opening TA is provided near the throttle valve 19. The throttle sensor 31 outputs a signal of the throttle opening TA and outputs an idle signal by an idle contact that is turned on only when the throttle valve 19 is at the fully closed position. On the downstream side of the air cleaner 15, there is provided an air flow meter 32 for detecting an intake air amount Q to the intake passage 11. In addition, the intake passage 1 is provided between the air cleaner 15 and the air flow meter 32.
An intake air temperature sensor 33 is provided to detect the temperature of the air taken in 1, that is, the intake air temperature THA.

Further, in the middle of the exhaust passage 12, an oxygen sensor 34 for detecting the oxygen concentration OX in the exhaust, that is, for detecting the exhaust air-fuel ratio in the exhaust passage 12 is provided. Further, the cylinder block 2 is provided with a water temperature sensor 35 that detects the temperature of the cooling water of the engine 1, that is, the cooling water temperature THW.

The ignition signal distributed by the distributor 20 is applied to the ignition plug 8 for each cylinder. The distributor 20 distributes the high voltage output from the igniter 21 to each ignition plug 8 in synchronization with the rotation of the crankshaft, that is, the crank angle. The ignition timing of each ignition plug 8 is determined by the high voltage output timing from the igniter 21.

The distributor 20 incorporates a rotor (not shown) which is rotated in association with the rotation of the crankshaft. And the distributor 20
A rotation speed sensor 36 for detecting the rotation speed of the engine 1, that is, the engine rotation speed NE from the rotation of the rotor is provided. Similarly, the distributor 20 is provided with a cylinder discrimination sensor 37 that detects a crank angle reference signal of the engine 1 at a predetermined rate according to the rotation of the rotor. In this embodiment, the crankshaft makes two rotations for a series of strokes in the engine 1,
The rotation speed sensor 36 detects the crank angle at a rate of 30 ° CA per pulse. The cylinder discrimination sensor 37 is 1
The crank angle is detected at a rate of 360 ° CA per pulse. Further, an automatic transmission 2 drivingly connected to the engine 1
7 is provided with a vehicle speed sensor 38 for detecting the speed of the vehicle, that is, the vehicle speed SP.

In addition, as shown in FIGS. 2 and 3, the intake passage 11 of this embodiment has a main bypass passage that bypasses the throttle valve 19 and connects the upstream side and the downstream side of the valve 19 to each other. 22 is provided. A known linear solenoid type idle speed control valve (ISCV) 23 is provided in the middle of the main bypass passage 22.
Is provided. The main bypass passage 22 is opened and closed by controlling the drive of the ISCV 23 based on a predetermined control signal. This ISCV
Reference numeral 23 denotes the engine 1 in which the throttle valve 19 is fully closed.
When the engine is idling, it is operated to stabilize the idling state, and the actual number of rotations is feedback-controlled so as to reach the target number of rotations when idling. Therefore, when the engine 1 is idling, by controlling the opening degree of the ISCV 23 and the valve opening time thereof, that is, by performing the ISC control,
The amount of air flowing through the main bypass passage 22 is adjusted, and the amount of intake air Q to the combustion chamber 7 is adjusted.

The intake passage 11 is also provided with an auxiliary bypass passage 24 that bypasses the throttle valve 19 and connects the upstream side and the downstream side of the valve 19 to each other. An idle adjusting screw 25 as an adjusting mechanism is provided in the middle of the auxiliary bypass passage 24. The screw 25 is adjusted from the outside by the operator's hand when adjusting the idle speed. That is, by rotating the screw 25, the opening area of the auxiliary bypass passage 24 is adjusted, and by extension, the idle speed is adjusted. In addition, this idol adjusting screw 2
5 is adjusted, idle speed adjustment switch 4
1 is turned on.

At the same time, the engine 1 is provided with a starter 26 for imparting a rotational force to the engine 1 by cranking when the engine 1 is started. Further, the starter 26 is provided with a starter switch 39 for detecting the operation / non-operation of the starter 26. As is well known, the starter switch 39 is turned on / off by operating an ignition switch (not shown), and the starter 26 is operated while the ignition switch is being operated. The starter signal STS of "on" is output.

The automatic transmission 27 constitutes a part of an external load together with, for example, an air conditioner (air conditioner) which is not shown. In addition, a neutral start switch 40 is provided inside the automatic transmission 27. The neutral start switch 40 detects that the current shift position ShP is in a neutral range [N range (including P range)]. That is, it is possible to detect whether the current shift position ShP is in the N range or the drive range (D range).

The injector 17, the igniter 21, and the ISCV 23 are electronic control units (hereinafter simply referred to as "EC
U ”) 51, and their drive timing is controlled by the operation of the ECU 51. The ECU 51 constitutes feedback control means, fixed adjustment control means, and predetermined opening degree setting means. This E
The CU 51 includes the above-mentioned throttle sensor 31, air flow meter 32, intake air temperature sensor 33, oxygen sensor 34,
Water temperature sensor 35, rotation speed sensor 36, cylinder discrimination sensor 3
7, a vehicle speed sensor 38, a starter switch 39, a neutral start switch 40, and an idle speed adjustment switch 41 (all or a part of these constitutes operating state detection means) are connected. And EC
The U51 controls each of the sensors 31 to 38, in order to control the ignition timing control of the engine 1, the fuel injection amount control, the ISC control, and the like.
Based on the output signals from the starter switch 39, the neutral start switch 40, and the idle speed adjustment switch 41, the injectors 17, the igniter 21, and the ISCV 23 are suitably driven and controlled.

Here, the electrical configuration of the ECU 51 will be described with reference to the block diagram of FIG. The ECU 51 includes a central processing unit (CPU) 52, a read-only memory (ROM) 53 that stores a predetermined control program and the like in advance, and a CPU 52.
A random access memory (RAM) 54 for temporarily storing the calculation results of the above, a backup RAM 55 for storing the stored data, a timer counter 56, and the like, and these units, an external input circuit 57, an external output circuit 58, and the like.
It is configured as a theoretical operation circuit connected by 9. In this embodiment, the ROM 53 stores IS such as "ISCV feedback control routine" described later.
A program related to C, or a predetermined map is stored in advance. In the present embodiment, the timer counter 56 not only performs a plurality of counting operations, but also outputs an interrupt signal at every predetermined time.

The external input circuit 57 includes the above-mentioned throttle sensor 31, air flow meter 32, and intake air temperature sensor 3.
3, oxygen sensor 34, water temperature sensor 35, rotation speed sensor 3
6, a cylinder discrimination sensor 37, a vehicle speed sensor 38, a starter switch 39, a neutral start switch 40, an idle speed adjusting switch 41, etc. are connected. Further, the external output circuit 58 includes the injectors 1
7, the igniter 21 and the ISCV 23 are connected to each other.

Then, the CPU 52 reads, as an input value, each signal input from each of the sensors 31 to 38, the starter switch 39, the neutral start switch 40, and the idle speed adjusting switch 41 via the external input circuit 57. Further, the CPU 51, based on the read input values, each injector 17, igniter 21 and I.
The SCV 23 is preferably drive-controlled.

Next, various processing operations in the engine idle speed adjusting device configured as described above will be described with reference to FIGS. FIG. 5 is a flow chart for explaining the “ISCV feedback control routine” executed by the ECU 51 during idling, and the routine is executed by a regular interruption every predetermined time on the assumption that the engine 1 is idling. .

When the processing shifts to this routine, first, at step 101, the ECU 51 causes the rotation speed sensor 3 to operate.
Based on 6, etc., various signals such as engine speed NE are read.

Next, at step 102, it is judged if the engine speed NE read this time is equal to the target speed NT. Here, the target rotation speed NT is a rotation speed suitable for idling and may be a predetermined constant value or a value calculated by a separate routine. Then, the engine speed NE is the target speed N
If equal to T, jump to step 106.

On the other hand, the engine speed NE is equal to the target speed N.
If it is not equal to T, the routine proceeds to step 103, where it is judged whether the engine speed NE read this time is larger than the target speed NT. And the engine speed N
If E is larger than the target rotation speed NT, it is determined that the idle rotation speed needs to be reduced in the future. Step 1
Move to 04. In step 104, a value obtained by subtracting the predetermined value d from the basic feedback value Di so far is set as a new basic feedback value Di, and the process proceeds to step 106.

The engine speed NE is equal to the target speed N.
If it is smaller than T, it is determined that the idle speed needs to be increased in the future, and the routine proceeds to step 105.
In step 105, a value obtained by adding the predetermined value d to the basic feedback value Di so far is set as a new basic feedback value Di, and the process proceeds to step 106.

After shifting from step 102, 104 or 105, in step 106, the correction term α is calculated based on the detection signals which have been read this time and which indicate various operating states. The correction term α is a comprehensive correction value that is determined based on the cooling water temperature THW, the intake air temperature THA, and the like at that time, for example.

Then, in the following step 107,
A value obtained by adding the correction term α calculated this time to the basic feedback value Di is set as the control duty ratio DUTY,
Thereafter, the processing is temporarily terminated.

As described above, in the above-mentioned "ISCV feedback control routine", the basic feedback value Di is set according to the engine speed NE at that time, and the correction term .alpha. Considering various operating states is added. Above, the control duty ratio DUTY is set. Then, the ECU 51 drives and controls the ISCV 23 based on the control duty ratio DUTY. As a result, when the engine 1 is operated, the engine speed NE, particularly during idling, is appropriately feedback-controlled.

Next, a learning process for ISC will be described. FIG. 6 is a flowchart showing a “learning processing routine” executed by the ECU 51. This routine is also the "ISCV feedback control routine" described above.
Similar to the above, on the assumption that the engine 1 is idling, it is executed by a regular interruption every predetermined time.

When the processing shifts to this routine, the EC
First, in step 201, the U51 detects the water temperature sensor 3
Based on 5, etc., various signals such as the cooling water temperature THW are read, and the basic feedback value Di set in the above "ISCV feedback control routine" is read.

Next, at step 202, it is judged whether or not the cooling water temperature THW read this time is equal to or higher than a predetermined water temperature H set in advance. Then, if the cooling water temperature THW is lower than the predetermined water temperature H, it is determined that the learning condition is not satisfied yet, and the subsequent processing is temporarily terminated.

Further, when the cooling water temperature THW is equal to or higher than the predetermined water temperature H, it is determined whether or not the present time is at a predetermined learning timing. Then, if the learning timing is not currently reached, it is determined that the learning should be abandoned this time, and the subsequent processing is once terminated as described above. If the learning timing is currently reached, the process proceeds to step 204 to update the learning value DG thereafter.

At step 204, the learning value DG at the present time and the basic feedback value Di read this time are read.
Determine if and are equal. Then, when the learning value DG at the present time is equal to the basic feedback value Di, it is determined that the learning value DG does not need to be newly updated, and the subsequent processing is temporarily ended. On the other hand, when the learning value DG at the present time is not equal to the basic feedback value Di, the process proceeds to step 205.

At step 205, the learning value DG at the present time is set to the basic feedback value Di read this time.
Is greater than or equal to. Then, if the learning value DG at the present time is larger than the basic feedback value Di, it is determined that the learning value DG needs to be updated to a smaller value than that, and the routine proceeds to step 206. Then, in step 206, a value obtained by subtracting the predetermined value e previously determined from the learning value DG up to that point is updated and set as a new learning value DG, and the subsequent processing is once ended.

If the learning value DG at the present time is smaller than the basic feedback value Di in step 205, it is judged that the learning value DG needs to be updated to a value larger than that, Move to 207. Then, in step 207, the value obtained by adding the predetermined value e determined in advance to the learning value DG up to that point is updated and set as the new learning value DG, and the subsequent processing is temporarily terminated.

As described above, in the "learning processing routine", when the learning condition is satisfied, the learning value DG is appropriately updated and set based on the basic feedback value Di set in the "ISCV feedback control routine". To be done. Therefore, for example, when sludge is accumulated in the main bypass passage 22 and the actual passage opening area becomes small, the basic feedback value Di becomes a relatively large value, so that the learning value DG also increases. It will be set to a relatively large value that is commensurate.

Next, when adjusting the idle speed,
The processing contents of the fixed control of the ISCV 23 controlled by the ECU 51 will be described. That is, when adjusting the idle speed, the idle adjusting screw 25 is adjusted from the outside by the operator's hand. Then, at this time, the ISCV as described in the related art is used.
Fixed control at a predetermined opening of 23 is executed. FIG. 7 shows E
"Fixed control routine during adjustment" executed by CU51
It is a flowchart which shows.

When the processing shifts to this routine, the ECU
First, in step 301, the water temperature sensor 35
Based on the above, various signals such as the cooling water temperature THW are read. The signal includes the switch signal TE1 of the idle speed adjustment switch 41 that is turned on when the idle adjusting screw 25 is adjusted, the air conditioner signal AC1 that is turned on when the air conditioner operates, and the like. There is. Further, the learning value DG set in the "learning processing routine" is also read.

Next, at step 302, it is judged whether or not the switch signal TE1 of the idle speed adjustment switch 41 read this time is on. When the switch signal TE1 is off, it is determined that it is not necessary to execute the fixed control in this routine, and the subsequent processing is temporarily terminated. If the switch signal TE1 is turned on in step 302, step 3
Shift to 03.

In step 303, it is determined whether or not the cooling water temperature THW read this time is equal to or higher than a predetermined temperature X. When the cooling water temperature THW is lower than the predetermined temperature X, it is determined that there is no fixed control condition,
Thereafter, the processing is temporarily terminated. When the cooling water temperature THW is equal to or higher than the predetermined temperature X, the process proceeds to step 304 to execute the fixed control thereafter.

In step 304, it is determined whether or not the air conditioner signal AC1 read this time is off.
When the air conditioner signal AC1 is off, it is determined that there is at least no load due to the operation of the air conditioner, and the process proceeds to step 305.

In step 305, the learning value DG set in the above "learning processing routine" and read this time is set as the stored value ACCA for the time being. Further, in the following step 306, it is determined whether or not the learning value DG is equal to or larger than the initial no-load initial value Y. here,
The no-load initial value Y is a value that is set in consideration of when the battery is removed, and is a value that is assumed when the air conditioner has no load. When the learning value DG is equal to or more than the no-load initial value Y, the process jumps to step 308. If the learning value DG is less than the no-load initial value Y, in step 307, the no-load initial value Y is set as the stored value ACCA in consideration of the influence of sludge or the like. That is, when the learning value DG is lower than the no-load initial value Y, the no-load initial value Y is set as the memory value ACCA, and the learning value DG is set.
Is equal to or greater than the no-load initial value Y, the learning value DG is set as the stored value ACCA.

Then, in step 308, the currently set storage value ACCA is set to the final duty ratio GA.
The setting is made as iSC, and the subsequent processing is once ended.

On the other hand, in step 304, when the air conditioner signal AC1 is on, it is determined that there is at least a load due to the operation of the air conditioner, and it is necessary to secure the intake air amount in consideration of this, and step 309 Move to.

In step 309, the value obtained by adding the correction term GAC considering the load of the air conditioner to the learned value DG read this time is set as the stored value ACCA for the time being.

Further, in the following step 310, it is determined whether or not the value obtained by adding the correction term GAC to the learning value DG is equal to or larger than the initial loaded initial value Z. Here, the loaded initial value Z is a value that is set in consideration of the time when the battery is removed, and is a value that is assumed when the air conditioner has a load. Then, the value obtained by adding the correction term GAC to the learning value DG is the loaded initial value Z.
In the above case, the process jumps to step 312. If the value obtained by adding the correction term GAC to the learned value DG is less than the loaded initial value Z, in step 311, the loaded initial value Z is considered in consideration of the influence of sludge or the like.
Is set as the stored value ACCA. That is, the learning value D
When the value obtained by adding the correction term GAC to G is less than the loaded initial value Z, the loaded initial value Z is set as the stored value ACCA, and the value obtained by adding the correction term GAC to the learned value DG is the loaded value. When it is equal to or larger than the initial value Z, the learning value DG is set as the stored value ACCA.

Then, in step 312, the currently set stored value ACCA is set to the final duty ratio GA.
The setting is made as iSC, and the subsequent processing is once ended.

Thus, the "fixed control routine during adjustment"
In, the final duty ratio GAiSC during fixed control is set based on the immediately preceding learned value DG set in the "learning processing routine" described above. Then, when the idle adjusting screw 25 is adjusted from the outside and the idle speed is adjusted, the opening of the ISCV 23 is fixedly controlled to a predetermined opening based on the final duty ratio GAiSC. Further, in this routine, the final duty ratio GAiS depends on whether or not the air conditioner is operating.
C is variable.

As described above, according to this embodiment, the following operational effects can be obtained. (B) That is, Idol adjusting screw 2
When 5 is adjusted from the outside and the idle speed is adjusted, the opening of the ISCV 23 is fixedly controlled to a predetermined opening. Therefore, workability in the adjustment work can be improved as compared with the case where the ISCV 23 is fully closed.

(B) When the opening of the ISCV 23 is fixedly controlled to the predetermined opening in this way, the final duty ratio GAiSC is set based on the learning value DG immediately before that. Then, the opening degree of the ISCV 23 is fixed based on the final duty ratio GAiSC.

Here, as shown in FIG. 8, when sludge is accumulated in the main bypass passage 22 over time due to EGR gas, blowback of gas from the combustion chamber 7, blow-by gas, or the like, As shown by the dashed line in FIG.
Even if the opening degree of the SCV 23 is the same, it becomes difficult to secure the intake flow rate as compared with the initial case (shown by the solid line). But,
In the present embodiment, even if the sludge accumulates over time in this manner, the predetermined opening degree is set based on the learning value DG that is associated with the accumulation and that is taken into consideration in the air flow rate during feedback control. Become. Therefore, a sufficient air flow rate is ensured when adjusting the idle adjusting screw 25. As a result, it is possible to suppress the occurrence of engine stall due to insufficient air volume.

(C) Further, in the present embodiment, in consideration of the immediately preceding learning value DG, the final duty ratio GAiSC is set so as not to fall below the initial initial values Y and Z. For this reason, the above-mentioned effects can be made more reliable.

(D) In addition, in the present embodiment, the correction term GAC is taken into consideration when setting the final duty ratio GAiSC depending on whether the air conditioner is operating or not. Therefore, more appropriate fixed control can be executed, and engine stall or the like due to the presence of a load such as air conditioner operation can be prevented.

The present invention is not limited to the above embodiment, but may be configured as follows, for example. (1) In the above embodiment, the final duty ratio GAiS
When setting C, the correction term GAC is taken into consideration depending on whether or not the air conditioner is operating, but the load may not be taken into consideration. Moreover, you may make it consider other loads (for example, automatic transmission 27) etc.

(2) In the above embodiment, the final duty ratio GAiSC is set so as not to fall below the initial values Y and Z in consideration of the immediately preceding learning value DG. That is, the lower limit of the learning value DG is set to the initial values Y and Z. On the other hand, a value larger than the initial values Y and Z may be set as the lower limit value.

(3) In the above embodiment, the present invention is embodied in the engine 1 equipped with the electronically controlled fuel injection device, but it is not limited to the electronically controlled type. Further, instead of the gasoline engine, for example, it may be embodied in a diesel engine.

(4) Learning value DG in the above embodiment
A separate method may be adopted as the setting method of. For example, the control duty ratio DUTY may be used as it is as the learning value.

The technical idea which is not described in the claims and can be grasped from the above-mentioned embodiment will be described below together with the effect thereof. (A) In the idle speed adjusting device for an internal combustion engine according to claim 1, the predetermined opening degree setting means also sets an external load applied to the internal combustion engine when setting the predetermined opening degree of the idle speed control valve. It is characterized by being considered.

With the above structure, the occurrence of engine stall due to the presence of a load can be suppressed, and the function and effect of the present invention can be made more reliable.

[0069]

As described in detail above, according to the present invention,
In an internal combustion engine that has a main bypass passage bypassing the throttle valve and an auxiliary bypass passage, an idle speed control valve in the middle of the main bypass passage, and an adjusting mechanism in the middle of the auxiliary bypass passage, When making the adjustment, it is possible to suppress the occurrence of engine stall due to insufficient air volume.

[Brief description of the drawings]

FIG. 1 is a conceptual configuration diagram illustrating a basic conceptual configuration of the present invention.

FIG. 2 is a schematic configuration diagram showing an engine idle speed adjustment device according to an embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view showing an intake passage and the like near a throttle valve.

FIG. 4 is a block diagram showing an electrical configuration of an ECU.

FIG. 5 is a flowchart showing an “ISCV feedback control routine” executed by the ECU.

FIG. 6 is a "learning processing routine" executed by the ECU.
It is a flowchart which shows.

FIG. 7 is a flowchart showing a “fixed control routine during adjustment” executed by the ECU.

FIG. 8 is a graph showing the relationship of the air flow rate of the main bypass passage with respect to the opening degree of ISCV.

[Explanation of symbols]

1 ... Engine as internal combustion engine, 12 ... Intake passage, 19
... Throttle valve, 22 ... Main bypass passage, 23 ... Idle speed control valve (ISCV), 24
... auxiliary bypass passage, 25 ... idle adjusting screw as adjusting means, 31 ... throttle sensor constituting operating state detecting means, 32 ... air flow meter constituting operating state detecting means, 33 ... suction constituting operating state detecting means Temperature sensor, 34 ... Oxygen sensor constituting operating state detecting means, 35 ... Water temperature sensor constituting operating state detecting means, 36 ... Rotation speed sensor constituting operating state detecting means, 37 ... Cylinder constituting operating state detecting means Discrimination sensor, 38 ... Vehicle speed sensor constituting driving state detection means, 3
9: Starter switch which constitutes the operating state detecting means, 4
0 ... Neutral start switch constituting operating state detecting means, 41 ... Idle speed adjusting switch constituting operating state detecting means, 51 ... Feedback control means,
E that constitutes fixed control means during adjustment and predetermined opening degree setting means
CU.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F02D 33/00 318L

Claims (1)

[Claims] 1. A throttle valve provided in the middle of an intake passage of an internal combustion engine, a main bypass passage provided so as to bypass the throttle valve, and a main bypass passage provided so as to bypass the throttle valve. An auxiliary bypass passage, an idle speed control valve provided in the middle of the main bypass passage for adjusting an air flow rate in the passage by opening and closing, an operating state detecting means for detecting an operating state of the internal combustion engine, and at least the internal combustion engine At the time of idling of the engine, a feedback control means for calculating a learning opening degree of the idle speed control valve based on the detection result of the operating state detecting means, and feedback controlling the opening degree of the valve based on the learning opening degree. The internal combustion engine is provided in the middle of the auxiliary bypass passage. When adjusting the number of revolutions during idling, the adjusting mechanism adjusts the air flow rate of the auxiliary bypass passage by being adjusted from the outside, and the number of revolutions during idling of the internal combustion engine is adjusted by the adjusting mechanism. In this case, in an idle speed adjusting device for an internal combustion engine, which comprises an adjusting fixed control means for fixedly controlling the idle speed control valve at a predetermined opening degree, in adjusting the adjusting mechanism, the adjusting fixed control means is used. A predetermined opening degree setting means for setting a predetermined opening degree of the idle speed control valve that can be fixedly controlled based on a learning value calculated by the feedback control means before adjustment of the idle speed adjusting mechanism is provided. An idle speed adjustment device for an internal combustion engine, characterized by: