JPH0968084A - Idle speed control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve follow up performance to the target rotating speed, and prevent reduction in the idle speed and blowing-up just after conditions of various loads change by correcting a suction air quantity when conditions of the various loads change in an idle condition. SOLUTION: In an idle speed control device of an internal combustion engine having an air quantity control valve 208 which is arranged in a bypass passage 207 to bypass a throttle valve 205 of an internal combustion engine 201 and can control opening of its bypass passage 207, when conditions of various loads change, operation is performed on deviation between a target value and a measured value of a suction air quantity, and the air quantity control valve 208 is driven by a control quantity on the basis of its deviation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for maintaining an engine speed at a target idle speed during idle operation of an internal combustion engine.

[0002]

2. Description of the Related Art When the idling speed decreases, an unpleasant vibration is given to the driver, and an engine stall (hereinafter abbreviated as "engine stall") is apt to occur when the vehicle starts. make worse.
For the above reasons, keep the idle speed as low as possible, and precisely adjust the idle speed so that the idle speed will not drop or stall even if the load fluctuates for some reason. Need to control.

A conventional idle speed control device that meets this demand is equipped with a control valve for adjusting the intake air amount of the internal combustion engine, and when an idle state is detected, a target based on at least various load states applied to the internal combustion engine. The rotation speed is calculated, and the control valve is controlled by a control amount based on the deviation between the target rotation speed and the actual rotation speed, so-called rotation speed feedback control is performed to match the rotation speed with the target rotation speed. ing. Incidentally, in such a conventional device, the rotation speed is set to the target rotation speed by stopping the rotation speed feedback for a preset time from the change of various load states until the rotation speed stabilizes. It prevents it from changing.

The operation of the above-mentioned conventional apparatus will be described in detail with reference to FIG. It is assumed that the idle state is determined before the time t1, and the rotation speed converges to the target rotation speed Xnt0 by controlling the opening degree of the control valve to Xs0 by the rotation speed feedback control. At time t1, when the compressor load of the air conditioner enters,
The rotation speed feedback control is stopped, and at the same time, the target value of the rotation speed is changed to a value Xnt1 preset according to the compressor load, and the opening of the control valve is set to the opening Xs1 preset according to the compressor load. Only Xs0 is opened and Xs1
Is controlled. After that, the rotation speed becomes X due to the generation of the compressor load and the intake delay of the air passing through the control valve.
The engine speed drops to nr1 and rises to a rotational speed Xnr2 at which the output of the internal combustion engine and the output loss including the compressor load are balanced and becomes stable. And after the compressor load has entered,
At time t2 when a preset time Xt has passed,
The rotation speed feedback control is restarted, and at time t3, when the opening degree of the control valve is controlled to Xs2 by the rotation speed feedback control, the rotation speed converges to the target rotation speed Xnt1. At time t4, when the compressor load is cut off, the rotation speed feedback control is stopped, the target value of the rotation speed is changed to Xnt0, and the opening of the control valve is preset according to the compressor load. The opening is closed by the opening Xs1 to Xs0 and controlled to the opening Xs3.
Thereafter, the rotational speed rises to Xnr4 due to the release of the compressor load and the intake delay of the air passing through the control valve, and the rotational speed Xnr at which the output of the internal combustion engine and the output loss are balanced.
It drops to 5 and stabilizes. Then, at time t5 when a preset time Xt has elapsed since the compressor load was cut off, the rotation speed feedback control is restarted, and at time t6, when the opening of the control valve is controlled to Xs4, The number converges to the target rotation speed Xnt0.

[0005]

However, in the above-mentioned conventional apparatus, the time from time t1 to time t3, the time from time t4 to time t6, and the number of revolutions deviate from the target value of the number of revolutions, The longer the time is, the more uncomfortable the driver may be. Also, if the engine speed Xnr1 immediately after the compressor load is excessively reduced causes vehicle vibration, and if the engine speed Xnr4 immediately after the compressor load is excessively increased causes a sense of blowing up the engine speed. There is a problem of giving a person discomfort.

Although the compressor load of the air conditioner is given as an example of the various loads, the same problem occurs even if the alternator load accompanying the headlight lighting, the hydraulic pump load of the power steering, and the like.

The present invention has been made in order to solve or alleviate the above-mentioned problems, and an object thereof is at least the time from the change of the states of various loads to the convergence to the target rotational speed. By reducing the opening degree of the control valve within the time period as compared to the case where it is kept constant, the discomfort given to the driver is eliminated, and the rotation speed fluctuation immediately after the state of each load is changed is reduced. Another object of the present invention is to provide an idle speed control device for an internal combustion engine, which can prevent the vibration of the vehicle body and the feeling of rising of the rotation speed and reduce the discomfort to the driver.

[0008]

In order to solve the above-mentioned problems, an idle speed control device for an internal combustion engine according to a first aspect of the present invention includes a control valve for adjusting the intake air amount of the internal combustion engine, and a rotational speed of the internal combustion engine. The rotational speed detection means for detecting the actual measurement value of the internal combustion engine, the intake air amount detection means for detecting the actual measurement value of the intake air amount of the internal combustion engine, the idle state detection means for detecting the idle state of the internal combustion engine, and various loads applied to the internal combustion engine. Load state detection means for detecting the state of, the temperature detection means for detecting the temperature of the cooling water circulating the internal combustion engine, the target rotation speed calculation means for calculating the target value of the rotation speed of the internal combustion engine, the various load of State, a target intake air amount calculation means for calculating a target value of the intake air amount according to the measured values of the cooling water temperature and the number of revolutions, and a measured value of the intake air amount when the states of the various loads change. Play the deviation from the target value A target deviation calculation means for, in which a driving means for driving the control valve in the control amount based on the deviation.

An idle speed control device for an internal combustion engine according to a second aspect of the present invention is a control valve for adjusting an intake air amount of the internal combustion engine, a rotational speed detecting means for detecting an actual measured value of the internal combustion engine, and an internal combustion engine. An intake pipe pressure detecting means for detecting the pressure of an intake pipe connected to the internal combustion engine, an idle state detecting means for detecting an idle state of the internal combustion engine, a load state detecting means for detecting various load states applied to the internal combustion engine, and an internal combustion engine. Temperature detection means for detecting the temperature of cooling water circulating through the engine, target rotation speed calculation means for calculating a target value of the rotation speed of the internal combustion engine, measurement of the states of the various loads, the temperature and rotation speed of the cooling water A target intake pipe pressure calculating means for calculating a target value of the intake pipe pressure according to the value; and a target deviation calculating means for calculating a deviation between the intake pipe pressure and the target value when the state of the various loads changes. Based on the deviation It is obtained by a drive means for driving the control valve in Ku control amount.

An idle speed control device for an internal combustion engine according to a third aspect of the present invention controls the opening of the control valve so that the measured value of the speed matches a target value at least when the idle state is detected. And a rotation speed feedback control stop / inhibit means for stopping or prohibiting the rotation speed feedback control when the states of the various loads are changed.

In the internal combustion engine idle speed control device according to a fourth aspect of the present invention, the target deviation computing means is configured to, when the state of the various loads changes while the speed feedback control is stopped or prohibited, the intake air. It is configured to calculate the deviation between the actual measured value and the target value.

In the idle speed control device for an internal combustion engine according to a fifth aspect of the present invention, the target deviation computing means is configured to, when the state of the various loads changes while the speed feedback control is stopped or prohibited, the intake pipe. It is configured to calculate the deviation between the pressure and the target value.

According to a sixth aspect of the present invention, in an idle speed control device for an internal combustion engine, a drive stopping means for stopping the driving means when a deviation between the measured value of the intake air amount and a target value is smaller than a preset value. Is further provided.

An idle speed control device for an internal combustion engine according to a seventh aspect of the present invention further comprises drive stop means for stopping the drive means when the deviation between the intake pipe pressure and the target value is smaller than a preset value. It is a thing.

An idle speed control device for an internal combustion engine according to an eighth aspect of the present invention comprises an atmospheric pressure detection means for detecting the pressure of the atmosphere.
A correction unit for correcting the target value of the intake air amount according to the pressure of the atmosphere is further provided.

According to a ninth aspect of the present invention, there is provided an idle speed control device for an internal combustion engine, which comprises atmospheric pressure detecting means for detecting atmospheric pressure,
A correction unit for correcting the detected target value of the intake pipe pressure by the atmospheric pressure is further provided.

According to the present invention, the target value of the intake air amount is set to be smaller as the rotational speed is higher, so that immediately after various loads are applied, the rotational speed at that time is the target rotational speed. The lower it is compared to, the more the intake air amount is increased,
Since the engine torque can be increased, the rotation speed rises quickly. Immediately after the various loads are cut off, as the rotational speed at that time is higher than the target rotational speed, the intake air amount can be reduced and the engine torque can be reduced, so that the rotational speed can be rapidly reduced. Therefore, it is possible to shorten the time from the state of various loads to the convergence of the actual number of revolutions to the target number of revolutions, and to reduce the number of revolutions immediately after the various loads are applied.
Also, it is possible to reduce the increase in the rotational speed immediately after the various loads are cut off.

Further, the target value of the intake air amount is set to be larger as the load is heavier, so that the heavier the load at that time, the larger the engine torque, and the lighter the load,
Since the engine torque can be reduced, it is possible to shorten the time from when the state of various loads changes until the actual rotational speed converges to the target rotational speed, regardless of the type of various loads,
It is possible to reduce the drop in the rotational speed immediately after the various loads are applied and the increase in the rotational speed immediately after the various loads are turned off.

Furthermore, by setting the target value of the intake air amount so that it becomes larger as the temperature of the cooling water becomes lower, the same operation as described above is achieved even in the cold state of the internal combustion engine.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. Embodiment 1. FIG. 1 is a schematic diagram of a rotation speed control device for an internal combustion engine embodying the present invention. In FIG. 1, 201 is an internal combustion engine, and an intake pipe 202 is connected to the internal combustion engine 201. In the intake pipe 202, an air amount sensor 203 as an intake amount detecting means for detecting an intake air amount of the internal combustion engine 201, and a throttle valve 20 whose opening is determined by the depression amount of an accelerator pedal 204 depressed by the driver.
5 and an idle switch 206 as an idle state detecting means for detecting the fully closed state of the throttle valve 205.

The throttle valve 205 is provided with a bypass passage 207 so as to bypass the throttle valve 205, and the bypass passage 207 is controlled to control the opening of the bypass passage 207 and adjust the amount of air passing through the bypass passage 207. An air amount control valve 208 as a valve is arranged. Reference numeral 209 is a rotation speed sensor as rotation speed detection means for detecting the rotation speed of the internal combustion engine 201, and 210 is a water temperature sensor as temperature detection means for detecting the temperature of the cooling water circulating in the internal combustion engine 201. Reference numeral 211 is a switch for detecting that the compressor load of the air conditioner is loaded, 212 is a switch for detecting that the hydraulic pump load of the power steering is loaded, and 213 is a switch for detecting that the headlight is turned on. Yes, these switches form the load state detecting means of the present invention. Further, the air amount sensor 203, the idle switch 206, the rotation speed sensor 20
The output signals of the water temperature sensor 210, the switches 211, 212, and 213 of various loads applied to the internal combustion engine are input to the control unit 214, and the target opening of the air amount control valve 208 is controlled by the control unit 214. It is output to the valve 208. still,
The control unit 214 includes a target rotation speed calculation means, a target intake air amount calculation means, a target deviation calculation means, a target intake pipe pressure calculation means, a rotation speed feedback control means of the present invention,
Speed feedback control stop / inhibit means, drive means,
It has a drive stop means, a correction means, and the like. As described in detail below, these means may be configured by software or, in some cases, by hardware such as an electric circuit.

Next, the control executed by the control unit 214 will be described with reference to FIG. FIG. 2 is a flowchart showing the operation of the rotation speed control device according to the present embodiment, which is repeatedly executed at predetermined time intervals. Incidentally, Znr, Zqr, Zwt, Znt, Zqt, Zia, Zib, Zi, which will be described later,
c, Zi, Zt, Znd, Zg, Zqd, and Zs are numerical values temporarily stored in a memory such as a RAM, and are initialized at the beginning of the program.

First, in step S301, the measured value Znr of the rotational speed detected by the rotational speed sensor 209 is stored in the memory, and in step S302, the air amount sensor 20 is stored.
The measured value Zqr of the intake air amount detected using 3 is stored in the memory, and the temperature Zwt of the cooling water detected using the water temperature sensor 210 is stored in the memory in step S303. In step S304, the target value Znt of the rotation speed is calculated and stored in the memory. The target value Znt of the rotational speed is at least the temperature Zwt of the cooling water and the switches 211, 2 for various loads.
It is calculated based on the states 12 and 213 (various load states). Further, in step S305, the target value Z of the intake air amount
Calculate qt and store in memory.

Here, once, the target value Zqt of the intake air amount is
The method of calculating is explained. FIG. 3 is a flowchart of a process (program) for calculating the target value Zqt of the intake air amount, which is executed in synchronization with the program routine shown in the flowchart of FIG. First, step S
At 401, the switch 211 is used to detect the state of the compressor load, and it is determined whether the compressor load is in the ON state. If it is determined that the compressor load is in the ON state, the process proceeds to step S402, and if it is determined that the compressor load is not in the ON state, the process proceeds to step S403. In step S402, a preset value Zqta for the coolant temperature Zwt is calculated using the function f1 shown in FIG. 4 and stored in the memory. In step S403, the switch 213 is used to detect the lighting state of the headlight and determine whether the headlight is in the ON state. Headlights on
If it is determined that it is in the state, the process proceeds to step S404, and if it is determined that it is not in the ON state, the process proceeds to step S405. In step S404, a preset value Zqta for the coolant temperature Zwt is calculated using the function f2 shown in FIG. 4 and stored in the memory. In step S405, the switch 212 is used to detect the turning state of the power steering, and it is determined whether the power steering is in the turning state. If it is determined that the power steering is in the steered state, the process proceeds to step S406, and if it is determined that the power steering is not in the steered state,
It proceeds to step S407. In step S406, FIG.
A preset value Zqta for the water temperature Zwt of the cooling water is calculated by using the function f3 shown in (3) and stored in the memory. In step S407, a preset value Zqta for the coolant temperature Zwt is calculated using the function f4 shown in FIG.
Store in memory. The value Zqt stored in the memory
a is the intake air amount when the rotational speed at which the output of the internal combustion engine 201 at each cooling water temperature Zwt and the output loss due to friction and various loads of the internal combustion engine 201 reach the target value Znt of the rotational speed. To do. In step S408, the measured value Znr of the rotation speed is calculated using the function f5 shown in FIG.
Then, a preset value Zqtb is calculated and stored in the memory. The value Zqtb is set to be smaller as the measured value Znr of the rotation speed is higher. Then, in step S409, the values Zqta and Zq stored in the memory are
The result obtained by adding tb is stored in the memory as the target value Zqt of the intake air amount. After calculating the target value Zqt of the intake air amount as described above, step S30 shown in FIG.
Go to 6.

In step S306, the basic air amount Zia that is at least necessary to maintain the target value Znt of the rotational speed is stored in the memory. The basic air amount Zia is at least the temperature Zwt of the cooling water and the switch 21 for various loads.
Calculation is performed based on the states of 1, 212, and 213. In step S307, the idle switch 206 is used to determine whether it is in the idle state. If it is determined not to be in the idle state, the process proceeds to step S313, and if it is determined to be in the idle state, the process proceeds to step S308. Step S308
Then, it is determined whether or not the states of the switches 211, 212, and 213 of various loads have changed, as compared with the previous execution of this program routine. If it is determined that there is no change, the process proceeds to step S310, and if it is determined that there is a change, the process proceeds to step S309 to store the preset value of Xt in the counter memory Zt. The counter memory Zt is a down counter that subtracts Xdt in step S501 at the timing of an interrupt signal generated every predetermined time, as shown in the flowchart of FIG. In step S310, the counter memory Z
It is determined whether t has a value of 0. Counter memory Zt
When it is determined that = 0, the process proceeds to step S311, and the correction amount Zib of the rotation speed feedback control is calculated and stored in the memory.

Here, a method of calculating the correction amount Zib of the rotation speed feedback control will be described with reference to the flowchart of FIG. FIG. 7 is a flowchart of a process (program) for calculating the correction amount Zib of the rotation speed feedback control, which is executed in synchronization with the program routine shown in the flowchart of FIG. In step S801, a value obtained by subtracting the target value Znt from the measured value Znr of the rotation speed is stored in the memory as the deviation Znd of the rotation speed. In step S802, it is determined whether or not the absolute value | Znd | of the deviation Znd of the rotational speed is equal to or greater than a preset value Xnd. If it is determined that | Znd | ≧ Xnd, step S
In step 803, a control gain Zg set in advance for the deviation Znd of the rotational speed is calculated using the function f6 shown in FIG. 8 and stored in the memory. If it is determined in step S802 that | Znd | ≧ Xnd is not satisfied, step S802
In step 804, the control gain Zg is stored in the memory as a value of 0. Then, in step S805, a value obtained by adding the control gain Zg to the previous correction amount Zib is stored in the memory as the current correction amount Zib. After calculating the correction amount Zib by the rotational speed feedback control as described above, the process proceeds to step S313 in FIG.

If it is determined in step S310 that the counter memory Zt is not 0, the flow advances to step S312 to calculate a correction amount Zic for intake air amount feedback control and store it in the memory. Here, a method of calculating the correction amount Zic of the intake air amount feedback control will be described with reference to FIG.
This will be described with reference to the flowchart in FIG. FIG. 9 is a flowchart of a process (program) for calculating the correction amount Zic of the intake air amount feedback control, which is executed in synchronization with the program routine shown in the flowchart of FIG. First, in step S1001, it is determined whether or not the correction amount Zic when the program routine was last executed is 0 or more. If it is determined that Zic ≧ 0,
In step S1002, the value Zic obtained by subtracting the preset value Xdq from the previous correction amount Zic is stored in the memory again. After the calculation in step S1002, the correction amount Zic
If the value shifts from a positive value to a negative value, step S100
At 3, the value of 0 is stored as the correction amount Zic. If it is determined in step S1001 that Zic ≧ 0 is not established, the process advances to step S1004 and the previous correction amount Z
The value obtained by adding the preset value Xdq to ic is stored again in Zic. After the calculation in step S1004, if the correction amount Zic shifts from a negative value to a positive value, step S1005
Then, a value of 0 is stored as the correction amount Zic. In step S1006, the switches 21 of various loads are
It is determined whether or not the states of 1, 212, and 213 have changed, as compared with the previous execution of this program routine. If it is determined that there is a change, the process proceeds to step S1007, and if it is determined that there is no change, the process proceeds to step S1009. In step S1007, the measured value Zqr of the intake air amount
The difference between the intake air amount Zqd and the target value Zqt
As stored in the memory. In step S1008,
Using the function f7 shown in FIG. 10, a preset correction amount Zic is calculated with respect to the deviation Zqd of the intake air amount and stored in the memory. After the correction amount Zic of the intake air amount feedback control is calculated as described above, step S100
At 9, the program routine of FIG. 9 is exited and the process proceeds to step S313 of FIG.

Further, in step S313, the basic air amount Z
ia, the correction amount Zib of the rotation speed feedback control and the correction amount Zic of the intake air amount are summed, and the calculation result is stored in the memory as the target value Zi of the bypass air amount passing through the air amount control valve 208. In step S314, FIG.
The target value Zi of the bypass air amount is converted into the target opening Zs of the air amount control valve 208 by using the function f8 shown in the above, and the calculation result is stored in the memory. The function f8 is
It shows the correlation between the bypass air amount and the opening degree of the air amount control valve 208, and is a so-called flow rate characteristic of the air amount control valve 208. Then, in step S315, the target opening Zs
The air amount control valve 208 is driven in accordance with the above.

Next, the operation of this embodiment will be described with reference to FIG. Before time t1, it is determined that the idle switch is in the idle state, and the switches 211, 212, and 213 of various loads are in the no-load state. The temperature Zwt of the cooling water is detected as Xwt, and the measured value Zqr of the intake air amount is detected as Xqr0. From the result of the cooling water temperature Xwt and the no-load state, the target value Znt of the rotational speed is set to Xnt0 and the basic air amount Zia is set to Xia0. Then, at least by the determination of the idle state, the rotation speed feedback control is executed to converge the rotation speed Znr to the target value Xnt0.
Before the time t1, the correction value Zib has a value of 0, so the bypass air amount Zi is set to Xia0.

At time t1, when the driver turns on the air conditioner, the compressor load switch 211 is turned on.
This is detected by using, and the rotation speed feedback control is stopped, and the basic air amount Zia is set to Xia1. Further, the target value Znt of the rotation speed is changed to Xnt1 corresponding to the compressor load, and the target value Zqt of the intake air amount is calculated based on the measured value Znr of the rotation speed, the cooling water temperature Xwt, and the compressor load Xqt1. Set to. The correction value Zic is set to a value Xic1 based on the deviation between the target value Xqt1 of the intake air amount and the actual measurement value Xqr0, and then set to 0x by Xdq every predetermined time.
Is gradually reduced until the value of is reached. (The bypass air amount Zi at this time is set to Zia + Zib + Zic.) Along with this, the rotational speed Znr depends on the generation of the compressor load and the air amount control valve 2
Due to the intake delay of the air passing through 08, the engine speed drops to Xnr1 and then rises to and stabilizes at a rotational speed Xnr2 at which the output of the internal combustion engine 201 and the output loss including the compressor load are balanced. Then, at time t2 when a preset time Xt has elapsed since the compressor load was applied, the rotation speed feedback control is restarted, and at time t3, when the correction value Zib is corrected to Xib3, the rotation speed Znr
Converges to the target value Xnt1.

At time t4, when the driver turns off the air conditioner, it is detected by the switch 211 of the compressor load, the rotation speed feedback control is stopped, and the basic air amount Zia is set to Xia4. Further, the target value Znt of the rotation speed is changed to Xnt0 corresponding to the no-load state, and the target value Zqt of the intake air amount is changed to the measured value Znr of the rotation speed.
And a value Xqt4 calculated based on the cooling water temperature Xwt and the compressor load. The correction value Zic is a value Xic based on the deviation between the target value Xqt4 of the intake air amount and the measured value Xqr4.
After being set to 4, the value is gradually increased by Xdq every predetermined time until the value becomes zero. (The bypass air amount Zi at this time is Zia
It is set to + Zib + Zic. ) Accordingly, the rotation speed Znr
Is increased to Xnr4 due to the release of the compressor load and the intake delay of the air passing through the air amount control valve 208, and then is decreased to the rotational speed Xnr5 at which the output of the internal combustion engine 201 and the output loss are balanced and stabilized. Then, at time t5 when a preset time Xt has elapsed since the compressor load was turned off, the rotation speed feedback control is restarted, and at time t6, when the correction value Zib is corrected to Xib6, the rotation speed Znr becomes It converges to the target value Xnt0.

As described above, according to this embodiment,
Regardless of the warm-up state of the internal combustion engine, immediately after the compressor load is applied, the intake air amount can be increased and the engine torque can be increased as the rotational speed at that time is lower than the target rotational speed. Rises quickly. Immediately after the compressor load is turned off, as the rotational speed at that time is higher than the target rotational speed, the intake air amount can be reduced and the engine torque can be reduced, so that the rotational speed rapidly decreases. Therefore, it is possible to shorten the time from when the state of the compressor load changes until it converges to the target number of revolutions, as well as the drop in the number of revolutions immediately after the compressor load is applied and the number of revolutions immediately after the compressor load is cut off. You can reduce the blowing up of.

In the present embodiment, the compressor load of the air conditioner is given as an example of the load applied to the internal combustion engine, but it is the alternator load associated with headlight lighting and the hydraulic pump load associated with power steering. Also has the same effect. Even for loads other than the above, by providing a switch or the like for detecting the state of the load and inputting the detection signal to the control unit 214, the same operational effect can be obtained.

Further, in the present embodiment, when the state of various loads changes, the rotation speed feedback control is stopped and the intake air amount feedback control is executed, but the apparatus which does not have the rotation speed feedback control is provided. In, it is also possible to implement intake air amount feedback control. Furthermore, a plurality of conditions for stopping or prohibiting the rotation speed feedback control are provided, and during the stop or prohibition of the rotation speed feedback control by any of the plurality of conditions, when the state of various loads changes, The intake air amount feedback control may be performed.

Furthermore, it is possible to carry out the intake air amount feedback control while the rotation speed feedback control is being carried out. In this case, when the intake air amount feedback control is performed when the states of various loads change, the intake air amount is quickly controlled to the intake air amount required to maintain the target rotation speed, so that the engine rotation speed is quickly changed. Stabilize. Therefore, the time during which the rotation speed feedback control should be stopped / prohibited (when the rotation speed is higher than the target rotation speed and the intake air amount is less than the intake air amount required to stabilize at the target rotation speed). , Or the state in which the rotational speed is lower than the target rotational speed and the intake air amount is larger than the air amount necessary to stabilize at the target rotational speed), it can be shortened compared to the conventional one
There is a possibility that the rotation speed feedback control can be continued even immediately after the state of various loads changes. In this way, when the state of various loads changes, the rotation speed feedback control is continuously executed, and the intake air amount feedback control is executed to reduce the time for the rotation speed to deviate from the target rotation speed. As compared with the case where the intake air amount feedback control is performed by stopping / prohibiting the rotation speed feedback control, it is possible to further reduce the feeling of discomfort given to the driver, and the decrease in the rotation speed immediately after various loads are applied. It is possible to reduce the increase in the number of revolutions immediately after the various loads are cut off, prevent the vibration of the vehicle body and the feeling of the increase in the number of revolutions, and reduce the discomfort given to the driver.

Although the idle switch 206 is used as the means for detecting the idle state in the present embodiment, instead of this, (1) the opening of the throttle valve 205 is detected, and the opening is a predetermined opening. It is also possible to use means for making the idle state when it is smaller, or (2) means for detecting the intake air amount or pressure of the intake pipe and making the idle state when the detected value is smaller than a predetermined value.

Further, the means for adjusting the intake air amount to the internal combustion engine in the present embodiment is the means for controlling the opening degree of the air amount control valve 208 provided in the bypass passage 207, but the throttle valve 205 is provided. A means for adjusting the opening degree of the throttle valve 205 by providing a connected actuator and controlling the actuator may be used.
In this case, the control valve of the present invention is constituted by the throttle valve 205.

Further, it is not necessary to limit the rotation speed feedback control to the above-mentioned means, and modifications can be made without departing from the spirit of the present invention. For example, the correction amount Zib in the present embodiment is added to the basic air amount Zia, but may be added to the basic air amount Zia.

The correction amount Zib in the present embodiment is used regardless of the state of various loads, but a plurality of correction amounts Zib are prepared and the plurality of correction amounts Zib are set according to the states of various loads. The correction amount Zib may be switched. In this case, the following effects can be obtained. That is, the causes of the change in the air amount for maintaining the idle target speed are (1) when the frictional force of the sliding portion of the internal combustion engine changes over time due to wear, (2) the intake air of the throttle valve, ISC, etc. When fine dust floating in the air adheres to the system gap and the flow rate characteristics change, (3) the gas pressure in the air conditioner changes and the compressor load changes, etc. If you do, Originally, the purpose of the rotational speed feedback control is to correct the changes over time in (1) to (3) above. However, a plurality of correction amounts Zib are prepared and the plurality of correction amounts Zib are set according to the states of various loads. When the correction amount Zib of (3) is switched, the change over time in (3) can be corrected particularly accurately.

It is not necessary to limit the counter memory Zt to the one described above, and modifications can be made without departing from the spirit of the present invention. For example, the counter memory Zt in the present embodiment subtracts Xdt by timing with an interrupt signal generated every predetermined time, but it may be executed in synchronization with the program routine shown in the flowchart of FIG. Good. Further, the counter memory Zt in the present embodiment is one in which Xdt is subtracted,
The counter memory Zt may be integrated for each Xdt, and it may be determined whether or not the rotation speed feedback control is stopped depending on whether the value of the counter memory Zt is equal to or less than a preset value. Further, although the counter memory Zt in the present embodiment stores a preset value of Xt regardless of the type of various loads when the state of various loads changes, a plurality of values Xt are prepared. Alternatively, the plurality of values Xt may be switched according to the states of various loads.

The intake air amount feedback control does not have to be limited to the above-mentioned means, and modifications can be made without departing from the spirit of the present invention. The above-mentioned correction value Zib is the deviation Zqd
Although it is a means for gradually reducing the value based on the deviation Zqd after setting the value based on the deviation Zqd, for example, (1) a means for gradually reducing the correction value Zib to the value based on the deviation Zqd. Alternatively, (2) means for setting the correction value Zib to a value based on the deviation Zqd and then gradually decreasing it by each value based on the deviation Zqd, or the like may be used.

The method of setting the target value of the intake air amount does not have to be limited to the above-mentioned means, and modifications can be made without departing from the spirit of the present invention. For example, when the target value Znt of the rotation speed is calculated based on at least the temperature of the cooling water, the value Zqt calculated based on the temperature Zwt of the cooling water.
a is a value Zqta calculated based on the target value Znt of the rotation speed
May be replaced with Further, the value Zqtb calculated on the basis of the measured value Znr of the rotation speed was added to the value Zqta calculated on the basis of the temperature Zwt of the cooling water, but it may be integrated.

The target opening Zs according to this embodiment is obtained by calculating the target value Zi of the bypass air amount according to various information and converting the target value Zi of the bypass air amount into the target opening Zs. Is. However, depending on various information,
The target opening Zs may be calculated directly. In this case, the target opening Zs is calculated according to at least the temperature Zwt of the cooling water and information on the states of the switches 211, 212, 213 of various loads (various load states).

Embodiment 2. In the intake air amount feedback control of the first embodiment, the deviation Z of the intake air amount
The calculation of the correction amount Zic may be stopped when qd is smaller than a preset value. Here, the correction amount Z
The method of calculating ic will be described.

FIG. 13 is a flow chart of a process (program) for calculating the correction amount of the intake air amount feedback control, which is executed in synchronization with the program routine shown in the flow chart of FIG. First, step S1
At 401, it is determined whether or not the correction amount Zic when the program routine was last executed is 0 or more. Zic ≧ 0
If it is determined that it is, the process proceeds to step S1402, and the value obtained by subtracting the preset value Xdq from the previous correction amount Zic is stored as Zic in the memory again. Incidentally, step S1
When the correction amount Zic shifts from a positive value to a negative value after the calculation of 402, a value of 0 is stored in the correction amount Zic in step S1403. Also, step S1401.
If it is determined that Zic ≧ 0 is not satisfied, then step S140.
4, the value obtained by adding the previously set value Xdq to the previous correction amount Zic is stored again in the memory as Zic. If the correction amount Zic shifts from a negative value to a positive value after the calculation in step S1404, the correction amount Zic is changed in step S1405.
The value of 0 is stored. Step S1
In 406, switches 211, 212, 21 of various loads
It is determined whether or not the state of 3 has changed compared with the time when this program routine was executed last time. If it is determined that there is a change, the process proceeds to step S1407, and if it is determined that there is no change, the process proceeds to step S1410. Step S1
At 407, a value obtained by subtracting the target value Zqt from the measured value Zqr of the intake air amount is stored in the memory as the deviation Zqd of the intake air amount.

In step S1408, it is determined whether or not the absolute value | Zqd | of the deviation Zqd of the intake air amount is greater than or equal to a preset value Xqd. If it is determined that | Zqd | ≧ Xqd, the process proceeds to step S1409, and if it is determined that | Zqd | ≧ Xqd is not satisfied, the process proceeds to step S1410. Step S1
At 409, the correction amount Zic set in advance for the deviation Zqd is calculated using the function f7 shown in FIG. 10 and stored in the memory. After the correction amount Zic of the intake air amount feedback control is calculated as described above, step S141
At 0, the program routine of FIG. 13 is exited and the process proceeds to step S313 of FIG.

As described above, according to the present embodiment, when the absolute value of the deviation Zqd of the intake air amount is small, the calculation of the correction amount Zic is stopped, so that the rotation speed immediately after the state of various loads is changed. The same effects as in the first embodiment can be obtained without meaningless control.

In this embodiment, | Zqd | ≧ Xqd
If it is determined that it is not, the correction amount Zic may be forcibly set to a value of 0.

Embodiment 3 FIG. 14 shows another embodiment of the present invention. In this embodiment, the intake pipe pressure sensor 215 that detects the pressure of the intake pipe 202 without using the air amount sensor 203 in the first and second embodiments.
The intake pipe 202 on the downstream side of the throttle valve 205.
The output signal of the intake pipe pressure sensor 215 is provided in the control unit 214. Thus, even if the detected value of the intake pipe pressure sensor 215 is treated as the intake air amount, the same operational effect as that of the first and second embodiments can be obtained.

Embodiment 4 FIG. 15 shows still another embodiment of the present invention. In this embodiment, the atmospheric pressure is low by detecting the atmospheric pressure and correcting the detected value of the intake pipe pressure sensor 215 or the target value of the intake air amount by the atmospheric pressure in the third embodiment. In high altitudes, it is possible to obtain the same effects as those of the first and second embodiments. As shown in FIG. 15, an intake pipe 20 is provided as means for detecting the pressure of the atmosphere.
The pressure sensor 216 may be provided in the vicinity of the inlet of the second pressure sensor 216, and the output signal of the pressure sensor 216 may be input to the control unit 214 to use the detection value of the pressure sensor 216 as the atmospheric pressure, or instead of the pressure sensor 216. In addition, the intake pipe pressure sensor 215 may be used, and the detection value of the intake pipe pressure sensor 215 when the internal combustion engine is stopped may be used as the atmospheric pressure.

As described above, according to the present invention, regardless of the warm-up state of the internal combustion engine and the types of various loads applied to the internal combustion engine, immediately after the various loads are applied, the rotational speed at that time is the target rotational speed. The lower it is compared to, the more the intake air amount is increased,
Since the engine torque can be increased, the rotation speed rises quickly. Immediately after the various loads are cut off, the intake air amount is reduced as the rotational speed at that time is higher than the target rotational speed.
Since the engine torque can be reduced, the rotation speed drops quickly. Therefore, the time from the change in the state of various loads to the convergence to the target speed is shortened at least as compared with the case where the opening degree of the control valve is kept constant within the time, and the driver feels uncomfortable. In addition to eliminating the above, the decrease in the number of revolutions immediately after various loads are applied, and the increase in the number of revolutions immediately after the various loads have been reduced are reduced to prevent the vibration of the vehicle body and the feeling of the increase in the number of revolutions. The discomfort given to the driver can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall configuration of an idle speed control device for an internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is a flow chart of a program showing a control operation according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing a process of calculating a target value of intake air amount according to the present invention.

FIG. 4 is a characteristic diagram showing a function for calculating a preset value for the water temperature of cooling water according to the present invention.

FIG. 5 is a characteristic diagram showing a function for calculating a preset value with respect to an actual measured value of the rotation speed according to the present invention.

FIG. 6 is a flow chart showing a process of counting switch state changes of various loads according to the present invention.

FIG. 7 is a flow chart showing a process of calculating a correction amount for rotation speed feedback control according to the present invention.

FIG. 8 is a characteristic diagram showing a function for calculating a preset control gain with respect to the deviation of the number of revolutions according to the present invention.

FIG. 9 is a flowchart showing a process for calculating a correction amount for intake air amount feedback control according to the present invention.

FIG. 10 is a characteristic diagram showing a function for calculating a preset correction amount for the deviation of the intake air amount according to the present invention.

FIG. 11 is a characteristic diagram showing a flow rate characteristic of the control valve according to the present invention.

FIG. 12 is an operating characteristic diagram according to the first embodiment of the present invention.

FIG. 13 is a flowchart showing a process of calculating a correction amount for intake air amount feedback control in an idle speed control device for an internal combustion engine according to a third embodiment of the present invention.

FIG. 14 is a schematic diagram showing an overall configuration of an idle speed control device for an internal combustion engine according to a third embodiment of the present invention.

FIG. 15 is a schematic diagram showing an overall configuration of an idle speed control device for an internal combustion engine according to a fourth embodiment of the present invention.

FIG. 16 is an operation characteristic diagram of a conventional idle speed control device for an internal combustion engine.

[Explanation of symbols]

201 internal combustion engine, 203 air amount sensor (intake amount detection means), 205 throttle valve, 206 idle switch (idle state detection means), 208 air amount control valve (control valve), 209 rotation speed sensor (rotation speed detection means), 210 water temperature sensor (temperature detection means), 211,
212, 213 Switches for various loads applied to the internal combustion engine (load state detection means), 214 Control unit (target rotation speed calculation means, target intake air amount calculation means, target deviation calculation means, target intake pipe pressure calculation means, rotation speed feedback control Means, rotation speed feedback control stop / inhibit means, drive means, drive stop means, correction means), 215 intake pipe pressure sensor (intake pipe pressure detection means), 216 pressure sensor (atmospheric pressure detection means).

Claims (9)

[Claims] 1. A control valve for adjusting an intake air amount of an internal combustion engine, a rotation speed detecting means for detecting a measured value of a rotation speed of the internal combustion engine, and an intake amount detection for detecting a measured value of an intake air amount of the internal combustion engine. Means, an idle state detecting means for detecting an idle state of the internal combustion engine, a load state detecting means for detecting a state of various loads applied to the internal combustion engine, and a temperature detecting means for detecting a temperature of cooling water circulating in the internal combustion engine. A target rotation speed calculating means for calculating a target value of the rotation speed of the internal combustion engine, and a target intake air calculating a target value of the intake air amount according to the states of the various loads, the temperature of the cooling water, and the measured values of the rotation speed. An amount calculation means, a target deviation calculation means for calculating a deviation between a measured value of the intake air amount and a target value when the states of the various loads are changed, and the control valve is driven by a control amount based on the deviation. Equipped with drive means, An idle speed control device for an internal combustion engine characterized by the above. 2. A control valve for adjusting an intake air amount of an internal combustion engine, a rotation speed detecting means for detecting a measured value of a rotation speed of the internal combustion engine, and an intake pipe for detecting a pressure of an intake pipe connected to the internal combustion engine. Pressure detection means, idle state detection means for detecting the idle state of the internal combustion engine, load state detection means for detecting the state of various loads applied to the internal combustion engine, and temperature detection for detecting the temperature of the cooling water circulating in the internal combustion engine. Means, target rotation speed calculation means for calculating a target value of the rotation speed of the internal combustion engine, and a target value of the intake pipe pressure according to the measured values of the states of the various loads, the temperature of the cooling water, and the rotation speed. Target intake pipe pressure calculation means, target deviation calculation means for calculating a deviation between the intake pipe pressure and a target value when the states of the various loads change, and the control valve is driven by a control amount based on the deviation. Drive means, An idle speed control device for an internal combustion engine, comprising: 3. A rotation speed feedback control means for controlling the opening degree of the control valve so that the measured value of the rotation speed matches a target value at least when the idle state is detected, and states of the various loads. 3. The idle speed control of the internal combustion engine according to claim 1 or 2, further comprising rotation speed feedback control stop / inhibit means for stopping or prohibiting the rotation speed feedback control when the engine speed changes. apparatus. 4. The target deviation calculation means calculates a deviation between a measured value of the intake air amount and a target value when the state of the various loads changes while the rotation speed feedback control is stopped or prohibited. The idle speed control device for an internal combustion engine according to claim 3, wherein 5. The target deviation calculation means calculates a deviation between the intake pipe pressure and a target value when the states of the various loads change while the rotation speed feedback control is stopped or prohibited. The idle speed control device for an internal combustion engine according to claim 3. 6. The drive stop means for stopping the drive means when the deviation between the measured value of the intake air amount and the target value is smaller than a preset value, further comprising: Idle speed control device for internal combustion engine. 7. The internal combustion engine according to claim 5, further comprising drive stopping means for stopping the driving means when the deviation between the intake pipe pressure and the target value is smaller than a preset value. Idle speed controller. 8. An atmospheric pressure detecting means for detecting atmospheric pressure, and a correcting means for correcting the target value of the intake air amount according to the atmospheric pressure. 7. The idle speed control device for an internal combustion engine according to any one of 4 and 6. 9. An atmospheric pressure detecting means for detecting atmospheric pressure, and a correcting means for correcting the detected target value of the intake pipe pressure by the atmospheric pressure. 8. The idle speed control device for an internal combustion engine according to any one of 2, 3, 5 and 7.