JPH0771291A - Idle speed control device for internal combustion engine - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] A device for controlling the idle speed of an internal combustion engine that executes ignition timing control to ensure appropriate operating characteristics according to the operating state of the internal combustion engine. Secure a stable idle speed regardless of fluctuations. [Structure] In order to secure a target idle speed by controlling a valve opening of an ISCV that controls conduction of a passage bypassing a throttle valve, firstly, an ignition timing advance angle calculated according to an operating state of an internal combustion engine is advanced. The amount ACLD is read, and the valve drive current duty component DACLD corresponding to the appropriate valve opening for that value is searched from the map (step 40).
0,402). If the idle switch (LL) indicating the idle state is on, the IS based on DACLD
While driving CV, when LL is off, ISCV is driven based on the previous value DACLD0 before the idle state is released (steps 404 to 416).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle speed control device for an internal combustion engine, and more particularly, to an idle engine for which an ignition timing control is executed in order to ensure appropriate operating characteristics in accordance with the operating state of the internal combustion engine. The present invention relates to an idle speed control device for an internal combustion engine suitable for speed control.

[0002]

2. Description of the Related Art In-vehicle internal combustion engines are required to be able to maintain a stable idle speed in order to achieve both a comfortable ride at idling and low fuel consumption. Therefore, conventionally, a device for controlling the idle speed of an internal combustion engine has been widespread. As such a device, a passage that bypasses the throttle valve provided in the intake pipe is provided, and by controlling the conduction of this passage, the amount of air that flows when the throttle valve is fully closed during idling is controlled. Things are widely known.

Here, the conduction control of the bypass passage is generally performed by controlling the opening degree of a valve called ISCV (Idle Speed Control Valve).
In this case, ISCV is the cooling water temperature (THW) of the internal combustion engine.
It is possible to maintain an appropriate idle speed by performing feedback control near the reference opening set based on the above.

By the way, it is required for a vehicle-mounted internal combustion engine to ensure good exhaust emission. For this reason, conventionally, a method has been adopted in which a catalyst device for purifying unburned components and the like in exhaust gas is disposed in an exhaust passage of an internal combustion engine mounted on a vehicle, thereby ensuring proper exhaust emission.

Here, the above-mentioned catalyst device cannot exert its purifying function until it reaches a predetermined activation temperature region, and cannot exert its sufficient purifying capability immediately after the internal combustion engine is started. It is a thing. In other words,
In order to obtain good exhaust emission, it is necessary to complete the warm-up of the catalyst device as soon as possible after starting the internal combustion engine.

As a method of satisfying such a demand, there is known a method of retarding the ignition timing immediately after the start of the internal combustion engine. By retarding the ignition timing, the combustion speed of the air-fuel mixture is retarded, and the gas under combustion is discharged as exhaust gas to raise the exhaust gas temperature.

However, such ignition timing retarding control intentionally raises the exhaust temperature by deteriorating the combustion efficiency, and is executed when a high output is required for the internal combustion engine. Not at all. Therefore, in recent years, it has become a mainstream to cancel the ignition timing retard control when the driver performs an acceleration operation and to control the ignition timing to the advance side in order to obtain good acceleration.

Thus, in recent years, in order to achieve both early warm-up of the catalyst device and good output characteristics of the internal combustion engine, ignition timing retard or advance control is generally performed. In an internal combustion engine having such a function, it is necessary to consider the ignition timing when performing the above-mentioned ISCV opening control. This is because, as long as the combustion characteristics of the air-fuel mixture change depending on the ignition timing, the idle speed changes with the change of the combustion characteristics unless some measures are taken.

Japanese Unexamined Patent Publication No. 1-253547 discloses an apparatus which pays attention to the above points and calculates the ISCV opening according to the set ignition timing. That is, when the ignition timing is advanced, the reference value of the valve opening is corrected to a small value in view of the improvement of the combustibility of the air-fuel mixture, and when the ignition timing is retarded, the combustibility deteriorates. In view of the above, the reference value of the valve opening is largely corrected to stabilize the idle speed.

[0010]

By the way, the above-mentioned conventional device is configured to reflect the variation of the ignition timing in the reference opening of the ISCV regardless of whether the internal combustion engine is in the idling state or not. That is, when the ignition timing gradually changes during the idling state, the fluctuation is canceled to stabilize the idling speed, and even when the idling state is canceled such as during acceleration, even if the ignition timing changes. If so, the reference opening of the ISCV is changed accordingly.

Therefore, when the internal combustion engine shifts to the acceleration state and the ignition timing is reversed to the advance angle control from the situation where the large ISCV opening is secured in the idling state under the ignition timing retarding control, this is accompanied. Thus, the ISCV opening is controlled to be small. In this case, since the total amount of air flowing through the intake pipe and the bypass passage affects the operating condition of the internal combustion engine, the change in the ISCV opening degree does not cause any adverse effect.

However, when the internal combustion engine is brought into the idling state again from such a situation, the ignition timing retard control is instantaneously restored, while the opening of the ISCV and the air flowing through the bypass passage in accordance with the opening. There is a problem because it takes a certain amount of time for the amount to return to a large value corresponding to the retard control.

That is, after the return of the idling state is detected from the state of the internal combustion engine, I
The time required for the SCV to open significantly and the time for the air that has passed through the ISCV that has been largely opened to reach the internal combustion engine after flowing through the bypass passage etc. The idle speed control is executed with an excessively small air amount corresponding to the ISCV corrected to be small, which causes a temporary decrease in the speed.

The present invention has been made in view of the above-mentioned points. When the internal combustion engine is in the idling state, the ISCV is driven at the reference opening according to the ignition timing, while when the idling state is exited. It is an object of the present invention to provide an idle speed control device for an internal combustion engine, which can solve the above problems by driving the ISCV based on the reference opening when the idling state is released.

[0015]

FIG. 1 shows a principle block diagram of an idle speed control device for an internal combustion engine which achieves the above object. That is, the above-mentioned object is, as shown in FIG. 1, an operation state detecting means 2 for detecting an operation state so as to control an ignition timing according to an operation state of the internal combustion engine 1, and a detection result of the operation state detecting means 2. An ignition timing control means 4 for supplying an ignition signal to an ignition plug 3 at a predetermined ignition timing calculated on the basis of the above, which is an apparatus for controlling an idle speed of an internal combustion engine, wherein an intake pipe 5 of the internal combustion engine 1 is provided. A bypass valve 7 for controlling the conduction of a passage bypassing the throttle valve 6 provided therein, and the bypass valve 7 capable of ensuring an appropriate idle speed for the ignition timing set by the ignition timing control means 4. In the idling engine speed control device for an internal combustion engine, which comprises a valve opening calculation means 8 for calculating the opening degree of the internal combustion engine 1, the internal combustion engine 1 is in the idling state by the operating state detection means 2. If Rukoto is detected, driving the bypass valve 7 according to the result of the operation of the valve opening calculating means 8, the operation state detection means 2
When it is detected that the internal combustion engine 1 is not in the idling state, the bypass valve 7 is driven to the opening degree set based on the calculation result of the valve opening degree calculation means 8 at the time when the idling state is released. This is achieved by an idle speed control device for an internal combustion engine, which is provided with valve drive means 9.

[0016]

In the idle speed control system for an internal combustion engine according to the present invention, when the internal combustion engine 1 is in the idling state, the throttle valve 6 is fully closed, so that the amount of air passing through the bypass valve 7 is changed. The idle speed is determined.

On the other hand, the internal combustion engine 1 is provided with the ignition timing control means 4 and has a function of varying the ignition timing according to the state detected by the operating state detection means 2. In this case, since the fluctuation of the ignition timing accompanies the change of the combustibility of the air-fuel mixture, it is necessary to correct the opening degree of the bypass valve 7 according to the fluctuation of the ignition timing in order to maintain a stable idle speed. .

The valve opening calculating means 8 calculates an opening for ensuring an appropriate idle speed with respect to the ignition timing set by the ignition timing controlling means 4 in consideration of such characteristics. Therefore, when the internal combustion engine is in the idling state, if the bypass valve 7 is driven according to the calculation result of the valve opening calculation means 8, a stable idle speed can be obtained.

However, the valve opening calculating means 8 is
When the ignition timing set by the ignition timing control means 4 fluctuates, the valve opening is updated to a new value regardless of the cause of the fluctuation. Then, the ignition timing control means 4
When the operating state detecting means 2 detects a state in which the ignition timing should be changed, the ignition timing is updated to correspond to the state change.

Therefore, even when the internal combustion engine 1 shifts from the idling state accompanied by the retard control of the ignition timing to the acceleration state, the ignition timing is advanced to ensure a high output, and as a result, the valve opening is performed. The calculation result of the degree calculation means 8 is
The opening is updated to a smaller value than when idling.

In this case, the bypass valve 7
If the opening degree is changed in accordance with the update of the calculation result, the idling speed is not appropriate due to the response speed of the bypass valve 7 and the air circulation time immediately after the idling state is restored again. There will be a decline.

On the other hand, in the present invention, while the valve driving means 9 drives the bypass valve 7 according to the calculation result of the valve opening calculating means 8 when the internal combustion engine 1 is in the idling state, When the internal combustion engine 1 is not in the idling state, it has a function of driving the bypass valve 7 based on the calculation result of the valve opening degree calculating means 8 at the time when the idling state is released.

Therefore, when the internal combustion engine 1 comes out of the idling state, the update of the calculation value executed by the valve opening calculating means 8 is not reflected in the opening degree of the bypass valve 7, and the idling state is maintained. At the time of return of, the appropriate idle speed will be secured immediately.

[0024]

FIG. 2 is a system configuration diagram of an internal combustion engine equipped with an idle speed control device according to an embodiment of the present invention.
In this embodiment, a multi-cylinder 4-cycle spark ignition type internal combustion engine 20 is used.
An example in which the present invention is applied is shown in the figure, and the figure shows a structural cross-sectional view of any one of multiple cylinders. In this internal combustion engine 20, each system unit is controlled by an electronic control unit (hereinafter referred to as ECU) 21 described later.

In the figure, a piston 23 that reciprocates in the vertical direction in the figure is housed in a cylinder block 22 of an internal combustion engine 20, and a combustion chamber 24 is connected to an intake manifold 25 via an intake valve 26. , Exhaust valve 2
It is connected to the exhaust manifold 28 via 7. An ignition plug 29 is provided in the combustion chamber 24 so that the plug gap projects.

An upstream side of the intake manifold 25 is connected to an intake pipe 31 via a surge tank 30 in common for multiple cylinders. The intake pipe 31 is provided with an intake air amount sensor 32 that generates a voltage signal according to the amount of air flowing, and a throttle valve 33 that controls the amount of air flowing through the intake pipe 31.

Here, the throttle valve 33 is constructed so that the opening degree is adjusted in association with the accelerator pedal,
When the accelerator pedal is fully closed, the intake pipe 31 is in a fully closed state to cut off the conduction. The opening is configured to be detected by a throttle position sensor 34 incorporating an idle switch LL that detects a fully closed state.

Further, the intake pipe 31 is provided with a bypass passage 36 that bypasses the throttle valve 33 and connects the upstream side and the downstream side of the throttle valve 33. Then, in the middle of the bypass passage 36, an ISCV in which the valve opening degree according to the duty ratio of the drive current is obtained
(Idle Speed Control Valve) 37 is attached. The ISCV is a valve corresponding to the bypass valve described above.

Therefore, even if the throttle valve 33 is fully closed, if the ISCV 37 is opened at an appropriate valve opening degree, air corresponding to the valve opening degree will generate air according to the valve opening degree.
3 will be bypassed and distributed. The idle speed control device of the present embodiment controls the idle speed when the throttle valve 33 is fully closed by appropriately controlling the opening of the ISCV 37.

Here, the intake air amount sensor 32 described above is used.
Is a configuration that always detects the total amount of air flowing through the intake pipe 31 and the amount of air flowing through the bypass passage 36 regardless of the opening of the throttle valve 33 and the opening of the ISCV 37. Therefore, the amount of fuel to be injected from the injector 38 in order to make the air-fuel mixture have an appropriate air-fuel ratio is I
It is sufficient that calculation is performed based on the detection result of the intake air amount sensor 32 regardless of the opening degree of the SCV 37 and the like.

Further, an oxygen concentration detection sensor (O ₂ sensor)
Reference numeral 39 is a sensor which is provided so as to partially penetrate the exhaust manifold 28 and detects the oxygen concentration in the exhaust gas before entering the catalyst device 40. This catalytic device 40
Is a member for purifying unburned components (CO, HC, etc.) and oxides (NOx, etc.) in the exhaust gas, and is the most efficient exhaust gas when the air-fuel ratio of the air-fuel mixture is maintained near the stoichiometric air-fuel ratio. The gas can be purified. O ₂ sensor 3 mentioned above
In view of such characteristics of the catalyst device 40, the internal combustion engine 20
It is provided in order to execute the feedback control so that the air-fuel mixture supplied to is accurately maintained near the stoichiometric air-fuel ratio.

A water temperature sensor 42 is provided in the cylinder block 22 of the internal combustion engine 20 so as to penetrate a part of the cylinder block 22 and project the tip into the water jacket. The water temperature sensor 42 is a sensor that emits an electric signal corresponding to the cooling water temperature THW of the internal combustion engine, and the ECU 21 detects the warm-up state of the internal combustion engine 20 based on the supplied electric signal and responds to the warm-up state. It executes various controls.

An igniter 43 is connected to the ECU 21 to generate a high-pressure ignition signal in accordance with an ignition timing signal transmitted by the ECU 21 at a predetermined timing.
The igniter 43 is connected to a distributor 44 that appropriately distributes the ignition signal generated by the igniter 43 to the ignition plugs 29 of each cylinder according to the rotation angle of the crankshaft.

Further, the distributor 44 incorporates a cylinder discrimination sensor 45 which generates a reference position detection signal of the crankshaft, and a rotation angle sensor 46 which generates a rotation speed signal of the internal combustion engine, for example, every 30 ° C. A. The pulse signals generated by the cylinder discrimination sensor 45 and the rotation sensors 46 are supplied to the ECU 21. Then, the ECU 21
Determines the transmission timing of the above-mentioned ignition timing signal using these pulse signals as reference signals.

By the way, the above-mentioned catalyst device 40 has a characteristic of exhibiting the function of purifying unburned components and the like in the exhaust gas only after the temperature is raised to a predetermined activation temperature range. Therefore, the above function of the exhaust gas is not exerted immediately after the internal combustion engine 20 is started, and it is necessary to warm up to the activation temperature region as early as possible in order to improve the exhaust emission.

In this case, it is effective to control the ignition timing to retard the exhaust temperature to raise the temperature. For this reason, the ECU 21 of the present embodiment is configured so that
When the cooling water temperature THW detected by 2 is not sufficiently warmed up, the ignition timing is retarded under constant conditions,
After that, the amount of retard angle is reduced with an increase in THW, and the process of ending the retard angle control is eventually performed.

By the way, when such a variation of the ignition timing occurs when the internal combustion engine 20 is idling, if the intake air amount is the same, the idling speed naturally varies. Therefore, in the device for stabilizing the idle speed by adjusting the opening of the ISCV 37 as in this embodiment, it is necessary to correct the opening of the ISCV 37 according to the variation of the ignition timing. Therefore, in this embodiment, ISCV3
Duty ratio Duty of drive current that determines valve opening of 7
Are set in the configuration as shown in FIG.

Here, DG in FIG. 3 is a basic duty component and is set to about 7% in this embodiment. Further, DTHW is a duty component set according to the cooling water temperature THW, and is 35% as shown in Table 1 below.
An appropriate value is set within the range.

[0039]

[Table 1]

The component indicated by DACLD in FIG. 3 is the duty component corresponding to the variation of the ignition timing described above, and in this embodiment, an appropriate value is set within the range of 18% as shown in Table 2 below. I am going to do it.

[0041]

[Table 2]

Here, in Table 2 above, ACLD represents the advance amount of the ignition timing, and is a value indicating how many times before the top dead center (BTDC) the ignition timing is set. That is, the case where the ACLD is 0 [° BTDC] is taken as a reference, and the case where the angle is retarded more than this (when ACLD is negative) is the case where the angle is advanced from this to compensate for the deterioration of the combustibility of the mixture (When ACLD is positive), the valve opening is largely corrected by the DACLD component in order to meet the request for improving the combustibility.

By the way, when the catalyst device 40 is warmed up early by retarding the ignition timing, if the retarding control is not canceled even when an acceleration request is generated during warming up, the operating characteristics are significantly deteriorated. It will be. Ignition timing retard control is
This is because the exhaust temperature is raised by intentionally deteriorating the combustibility of the air-fuel mixture, which is accompanied by the deterioration of the output characteristics.

Therefore, in this embodiment, as shown in Table 3 below, when the idle switch LL is on,
The advance amount of the ignition timing is set in three cases where the intake air amount Q / N per one revolution of the engine, which represents the load state of the internal combustion engine 20, is small and large.

[0045]

[Table 3]

In this case, the advance amounts ACLD set in Tables 3 to 3 are both set to the advance side (positive value) when the cooling water temperature THW is below −10 ° C. in extreme cold. This is because under such a circumstance, the operation of the internal combustion engine 20 in a stable state has priority over early warm-up of the catalyst device 40, and therefore advance control that is advantageous for combustion of the air-fuel mixture should be performed.

When THW is near 0 ° C., Table 3
As shown in the middle of the figure, a negative value is executed to execute the ignition timing retard control, and as shown in Table 3, when the idling state is released, a positive value is secured to ensure good output characteristics. The values are set as ACLD.

Therefore, the DAC shown in FIG.
The LD component varies not only as a function of the cooling water temperature THW but also depending on the load state of the internal combustion engine. For example, when THW is 10 ° C. and the engine is rapidly accelerated from the idling state, the ACLD becomes “−”. As it changes from 10 "to" 3 "(Table 3), it decreases from 14% to around 0% (Table 2).

FIG. 4 shows the state of change of the engine speed NE (FIG. 4A), the state of change of the idle switch LL (FIG. 3B), and the ignition timing advance value AC when such a situation occurs.
Change state of LD (FIG. 7C), change state of the DACLD component (FIG. 3D), and intake air amount G per revolution supplied to the internal combustion engine 20 via the bypass passage 36.
The change status of / N ((E) in the figure) is shown.

In other words, when the idling state is released at time t ₁ (FIG. 2B) and the NE rises accordingly (FIG. 2A), as described above in order to respond to the change. The ACLD ((C) in the figure) and the DACLD change (the situation shown by the broken line in the (D) in the figure).

Therefore, if the change in DACLD is reflected in the opening of the bypass valve 37, the Q / N reaching the internal combustion engine 20 via the bypass passage 36 is delayed in the response of the bypass valve 37. And bypass valve 37
From the internal combustion engine 20 to the internal combustion engine 20 with a delay resulting in a decrease as indicated by the broken line in FIG.

When the Q / N decreases in this way, at time t ₂ , the throttle valve 33 is fully closed and the idling state is restored ((B) in the figure), and at the same time, A
Even if CLD ((C) in the same figure) and DACLD are restored (the situation shown by the broken line in (D) in the same figure), as long as a predetermined delay time elapses as shown in (E) in the figure, Q / Since N does not return, the engine speed NE is temporarily reduced unreasonably (the situation indicated by the broken line in FIG. 7A).

The idle speed control system of the present embodiment prevents the engine speed NE from being lowered and smoothly returns to a stable idling state as shown by a solid line or a one-dot chain line in FIG. 4 (A). It is characterized in that it can be achieved.

In the following, the ECU 21 is designed to exert such a function.
The processing executed by will be described in detail.

FIGS. 5 and 6 are flowcharts of an example of an A / D conversion routine for calculating a parameter value indicating the operating state of the internal combustion engine 20 from the outputs of various sensors connected to the ECU 21, and a main routine. Show. In the present embodiment, the ECU 21 implements the above-mentioned operation state detecting means 2 by performing these processes.

That is, as shown in FIG. 5, the ECU 21
The A / D conversion is performed on the output signal of the throttle position sensor 34 every 8 ms for the throttle opening TA whose state changes relatively frequently (step 100), and every 64 ms for the cooling water temperature THW which changes relatively slowly. The output signal of the water temperature sensor 42 is A / D converted to (step 10
2) and 4 for the intake air amount GA that changes frequently
The output signal of the intake air amount sensor 32 is A / D converted every ms (step 104) to grasp the situation change.

Then, the main routine shown in FIG. 6 is executed based on the value converted into a digital signal by executing the above routine and the pulse signal representing NE supplied from the rotation angle sensor 46, and the throttle opening TA, The cooling water temperature THW and the intake air amount G / N per one revolution obtained from the intake air amount GA and the engine speed NE are calculated (steps 200 to 208).

FIG. 7 shows ignition based on the operating state of the internal combustion engine 20 detected by executing the routines shown in FIGS. 5 and 6 and the ACLD map shown in Table 3 which the ECU 21 stores in advance. The flowchart of an example of the routine which calculates the advance amount of a time is shown. In the present embodiment, the ignition timing control means 4 is realized by the ECU 21 executing such a routine.

That is, when the routine shown in FIG. 7 is started, first, at step 300, the value of the cooling water temperature THW is input, and at step 302, whether the idle switch LL is on, that is, whether the internal combustion engine 20 is idling or not. Determine. If it is determined that the LL is not turned on, the process proceeds to step 304 and the internal combustion engine 20
It is determined whether or not the G / N representing the load state of No. exceeds a predetermined value.

As shown in Table 3 above, in this embodiment, three maps (Table 3 to) are set for THW according to the load state of the internal combustion engine 20, and which map should be referred to. This is to determine whether.

When the load state of the internal combustion engine 20 is specified by the processing of steps 302 and 304, the process proceeds to any one of steps 306, 308 and 310 according to the state and the ACLD map shown in Table 3 The corresponding map of is searched by THW. Then, when the advance amount ACLD corresponding to the load state and the warm-up state of the internal combustion engine 20 is searched in this way, the search result is stored in the memory in step 312, and then the process proceeds to step 314.

Step 314 is a step for obtaining the final calculated value AOP of the ignition timing. In this embodiment,
In addition to the above-mentioned ACLD, the concept of the reference advance value ABSE calculated from various parameters according to the characteristics of the internal combustion engine 20 is also introduced, and these added values are used as the final calculated value AOP.
I am trying.

Thereafter, the routine proceeds to step 306, where the igniter 43 is based on the ignition timing AOP thus obtained.
The ignition timing signal is output toward and the present routine ends. As a result, in the internal combustion engine 20, the catalyst device 40
The early warming up and the operating characteristics during the warming up are compatible with each other.

In response to the ignition timing control executed in this way, the ECU 21 executes the ISCV duty ratio calculation routine shown in FIG. 8 to stabilize the idle speed. Hereinafter, with reference to FIG. 8 which is a flowchart of an example of the ISCV duty ratio calculation routine, the ECU 21 described above calculates the valve opening degree calculation means 8
The contents of the processing executed to realize the valve driving means 9 will be described.

When the routine shown in FIG. 8 is started, first, at step 400, the advance amount ACLD calculated in the routine shown in FIG. 7 is input. This routine is a routine that is executed in order to maintain a stable idle rotation speed in consideration of fluctuations in the ignition timing.
This is because it is a prerequisite to detect

Then, when the input of the ACLD is completed, the process proceeds to step 402, the DACLD map shown in the above Table 2 is searched by the input ACLD, and the search result is stored as tDACLD. The idle speed control device of this embodiment is
The feature is that the tDACLD thus stored is used only when the internal combustion engine 20 is in the idling state.

That is, after the processing of the above step 402 is completed, it is determined in the following step 404 whether the idle switch LL is on. If it is determined that the LL is not on, the previous DAC is executed in step 406.
A process of loading the LD value DACLD0 is performed. Then, in step 410, this DACLD0 is changed to the current DAC.
It is stored as an LD, and in step 412, the previous DACLD0 is stored again as a new DACLD0.

Whether or not the engine is idling depends on whether or not the idle switch LL is turned on as described above, whether the change amount ΔG / N of the intake air amount G / N is larger than a predetermined judgment value, or the throttle valve. Change amount Δ of the opening degree TA of 33
It can also be determined by whether TA exceeds a predetermined determination value, or the like.

On the other hand, if it is determined in step 404 that LL is on, that is, the internal combustion engine 20 is in the idling state, then the routine jumps to step 410, and the value obtained this time and stored in tDACLD. Is stored as a new DACLD, and its value is stored as a new DACLD0 in step 412.

As a result, the value of DACLD stored in step 410 is appropriately updated to a new value when the internal combustion engine 20 is in the idling state, but when the idling state is released, immediately before the release. It will be fixed to the DACLD required for.

That is, as the internal combustion engine 20 is cold-started and warmed up, the advance amount A during idling is increased.
When the CLD fluctuates, this fluctuation of the ACLD is appropriately reflected in the DACLD, and the ISCV is controlled to a valve opening degree that can maintain a stable idle speed.
When the ACLD changes as the load state of the internal combustion engine 20 changes as shown in FIG. 4, the DACLD is not affected by the change as shown by the solid line in FIG.

Therefore, in the idle speed control system of the present embodiment, the opening degree of the ISCV 37 does not fluctuate after the time t _{1 in} FIG. 4, and therefore the G / A that reaches the internal combustion engine 20 via the ISCV 37 is changed. N also does not change as shown by the solid line in FIG. 4 (E), and when the idling state is restored at time t ₂ , immediately after that, as shown by the solid line in FIG. 4 (A), a stable idle speed is obtained. Will be secured.

As described above, the duty ratio Duty of the drive signal of the ISCV 37 is a value obtained by adding the fluctuation component DACLD corresponding to the advance amount ACLD to the fluctuation component corresponding to the cooling water temperature THW and the fixed component DG. . For this reason, when the processing up to step 412 is completed, then step 4
The routine proceeds to step 14, where Duty = DTHW + DACLD + DG is calculated, and in step 416, the ISCV 37 is driven based on the calculated value, and this routine is ended.

FIG. 9 shows a flowchart of another example of the ISCV duty ratio calculation routine executed by the ECU 21 of this embodiment to execute the valve opening calculation means 8 and the valve drive means 9. In addition, step 500 in the figure
The processing contents of 504, 510 to 516 are the same as those of steps 400 to 404, 410 to 416 in FIG.

That is, the routine shown in FIG. 9 is characterized by the processing contents of steps 506 and 508 executed when it is determined in step 504 that the idle switch LL is not on.

That is, when it is detected in step 504 that LL is off (the internal combustion engine 20 is in the non-idling state), in this routine, the DACLD immediately before the idling state is released in step 506, that is, the previous DACLD. From the value DACLD0 of the predetermined value α
Is subtracted and the value is stored as DACLD1.

Further, step 508 is a step of guarding DACLD1 so as not to be less than the predetermined value β, and DACLD1 calculated in step 506 above.
If is less than β, the process of substituting β in DACLD1 is performed.

When the value of DACLD1 is determined in this way, the DACLD1 is subsequently determined in the same manner as the routine shown in FIG.
The value of 1 is stored as new DACLD and DACLD0 (steps 510 and 512), and the ISCV 37 is driven based on the new DACLD (steps 514 and 51).
6) The current process ends.

After this, every time this routine is started, the processing from step 500 onward is repeatedly executed, and step 5
When it is continuously determined that the internal combustion engine 20 is in the non-idling state in 04, DACLD gradually decreases within the range of the predetermined value α with β being the minimum value. And
As soon as the idling state returns, the ignition timing advance amount ACL
The value set according to D is adopted as DACLD (steps 500 to 504, 510).

Assuming that such processing is performed, FIG.
As indicated by the alternate long and short dash line therein, at time t ₁ , the internal combustion engine 2
When the idling state of 0 is released, D
The ACLD decreases, and as a result, the air amount G / N reaching the internal combustion engine 20 via the ISCV 37 also gradually decreases with a predetermined delay time.

By the way, the internal combustion engine 20 shifts from the idling state to the non-idling state at time t ₁ ,
After that, when the non-idling state continues for a relatively long period of time, the warm-up of the internal combustion engine 20 progresses during that period and the THW
Will rise. In this case, the amount of retardation required at the time of returning to the idling state is smaller than that required before the idling state is released, and immediately after returning (time t in FIG. 4).
₂ Immediately after) DACLD is released from idling state (Fig. 4)
It is desirable that it is appropriately reduced as compared with the DACLD at the middle time t ₁ ).

On the other hand, when this routine is executed, the DAC in the non-idling state as described above is used.
The LD is gradually reduced. For this reason, it is possible to properly match the required value of DACLD at the time of returning to the idling state and the value of DACLD in the non-idling state, which is more practical than when the routine shown in FIG. 8 is executed. Along with this, it is possible to realize control.

It should be noted that when the idling state is restored at time t ₂ , DA that is still required before time t ₁
Even if a DACLD equivalent to CLD is required,
Since DACLD is guarded at β or more, the gap is small, and the engine speed NE does not unduly decrease as shown by the alternate long and short dash line in FIG. 4 (A).

By the way, in the routines shown in FIGS. 8 and 9, it is determined whether the DACLD is updated or frozen at any time according to the advance amount ACLD based on the state of the idle switch LL. However, in addition to this, the determination may be performed by paying attention to, for example, the sign of the advance amount ACLD, the value of DACLD, or the change amount of DACLD (the size of DACLD0-DACLD).

[0085]

As described above, according to the present invention, when the ignition timing fluctuates according to the change in the operating state of the internal combustion engine, the opening degree of the bypass valve fluctuates according to the fluctuation. Therefore, the change in the combustibility of the air-fuel mixture due to the change in the ignition timing is offset by the change in the amount of air supplied to the internal combustion engine during idling, and an appropriate idle speed is maintained.

When the opening of the bypass valve has no direct effect on the operating characteristics of the internal combustion engine, even when the ignition timing changes, the change is reflected as a change in the opening of the bypass valve. Therefore, the opening of the bypass valve when the idling state is restored is
It is possible to smoothly restore the stable idling state without largely deviating from the opening that can secure an appropriate idle speed.

As described above, according to the idle speed control device for an internal combustion engine of the present invention, various characteristics required for the internal combustion engine are appropriately ensured by performing the ignition timing control, and at the time of idling, It has the feature that an appropriate idle speed can be secured.

[Brief description of drawings]

1 is a principle configuration diagram of an idle speed control device for an internal combustion engine according to the present invention.

FIG. 2 is an overall configuration diagram of an idle speed control device for an internal combustion engine that is an embodiment of the present invention.

FIG. 3 is a diagram illustrating components of a duty ratio of an ISCV drive signal.

FIG. 4 is a time chart for explaining the operation of the device of this embodiment.

FIG. 5 is an A / D executed by an electronic control unit of the apparatus of this embodiment.
It is a flowchart of an example of a conversion routine.

FIG. 6 is a flowchart of an example of a main routine executed by the electronic control unit of the apparatus of this embodiment.

FIG. 7 is a flowchart of an example of an advance angle value calculation routine executed by the electronic control unit of the apparatus of this embodiment.

FIG. 8 is an ISC executed by the electronic control unit of the apparatus of this embodiment.
9 is a flowchart of an example of a V duty ratio calculation routine.

FIG. 9 is an ISC executed by the electronic control unit of the apparatus of this embodiment.
8 is a flowchart of another example of the V duty ratio calculation routine.

[Explanation of symbols]

1, 20 Internal combustion engine 2 Operating state detecting means 3,29 Spark plug 4 Ignition timing control means 5,31 Intake pipe 6,33 Throttle valve 7 Bypass valve 8 Valve opening calculation means 9 Valve driving means 21 Electronic control unit (ECU) 32 Intake air amount sensor 34 Slitter position sensor 36 Bypass passage 37 ISCV 38 Injector 39 O ₂ sensor 40 Catalyst device 42 Water temperature sensor 46 Rotation angle sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F02D 41/16 D 8011-3G F02P 5/15

Claims (1)

[Claims] 1. A driving state detecting means for detecting a driving state so as to control an ignition timing according to a driving state of an internal combustion engine,
An apparatus for controlling an idle speed of an internal combustion engine, comprising: an ignition timing control means for supplying an ignition signal to an ignition plug at a predetermined ignition timing calculated based on a detection result of the operating state detection means. A bypass valve that controls conduction of a passage that bypasses the throttle valve in the intake pipe of the engine, and an opening degree of the bypass valve that can secure an appropriate idle speed with respect to the ignition timing set by the ignition timing control means In the idling engine speed control device for an internal combustion engine, comprising: a valve opening calculation means for performing a calculation of the valve opening calculation means when the operating state detection means detects that the internal combustion engine is in an idling state. The bypass valve is driven according to the result, and the internal combustion engine is not in the idling state by the operating state detecting means. Is detected, the valve drive means for driving the bypass valve to an opening set based on the calculation result of the valve opening calculation means at the time when the idling state is released is provided. Idle speed control device for internal combustion engine.