JP3287863B2 - Idle speed control device for internal combustion engine - Google Patents

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 speed control device for controlling an idle speed according to application and removal of a load in the engine. .

[0002]

2. Description of the Related Art Conventionally, as this kind of technique, for example, a technique disclosed in Japanese Patent Publication No. 64-11616 has been known. In this technique, a bypass intake passage that bypasses a throttle valve provided in an intake passage of an internal combustion engine is provided, and an electromagnetic control valve for opening and closing is provided in the middle of the bypass intake passage. By controlling the electromagnetic control valve, the air flow rate passing through the bypass intake passage is controlled, and by correcting the intake air flow rate of the engine in the idle operation state, the idle speed is controlled. The feedback control is performed so as to be equal to. In addition, the correction amount of the intake air flow rate at the time of idling-up is a large difference between the control target rotation speed when a load such as an air conditioner is applied to the engine and the control target rotation speed when the load is removed. It is controlled to be as large as possible.

[0003]

However, in the above prior art, the intake air is determined based on the difference between the control target rotation speed when the load is applied and the control target rotation speed when the load is removed. The correction amount of the flow rate was determined. Therefore, when a load whose characteristics change according to the engine speed is applied to the engine, even if the difference between the actual speed and the control speed is the same, the required intake air amount differs depending on the speed. However, the actual rotation speed may not be the control target rotation speed.

For example, as shown in FIG. 19, when a shift range is switched from a neutral range or a parking range to a drive range in an automatic vehicle, a so-called drive range load and an electric load such as an air conditioner are as shown in FIG.
It increases as the engine speed increases. At this time, the relationship between the required intake air flow rate when the load is removed (no load) and the required intake air flow rate when the load is applied (with load) is as shown in FIG. Then, as shown in the figure, when the electric load is applied from the no-load point A to the loaded point B when the electric load is applied, and when the electric load is applied from the no-load point C at a higher engine speed. Comparing with the case where the idle-up to the loaded point D at that time, even if the differences a and b between the control target rotational speeds are the same, the correction amounts c and d of the bypass intake air flow rates required in both cases are different. Come. Therefore, in theory, when the increase correction is necessary by the correction amount d, the increase correction is actually performed only by the correction amount c smaller than that,
Conversely, when the increase correction by the correction amount c is sufficient, the increase correction is performed by the correction amount d larger than that. As a result, the intake air flow required for idling up cannot be obtained due to changes in the engine speed,
The application or removal of the load may cause the engine speed to overshoot or undershoot.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has as its object to reduce the rotational speed even when a load whose load characteristics change with a change in rotational speed is applied to or removed from the internal combustion engine. of an internal combustion engine capable of controlling the speed to accurately control target rotational speed idle rotational speed control instrumentation
To provide a location .

[0006]

In order to achieve the above object, according to the present invention, an actual rotation speed of an internal combustion engine is detected, and the engine speed is determined based on a difference between the detected rotation speed and a control target rotation speed. by bypassing the throttle valve
The engine rotation speed during idle operation is controlled to be equal to the control target rotation speed by adjusting the intake air flow rate of the path intake passage, and the control target rotation speed when a predetermined load is applied to the engine and the control target rotation speed The control target rotation speed when the load is removed depends on the engine state at that time.
In the idle speed control device for an internal combustion engine, the two types of control amounts have different transition tendencies depending on the control target rotation speed, and a predetermined load is applied to the engine. First and second control amounts for obtaining the amount of intake air required to maintain the target rotation speed corresponding to the respective control target rotation speeds when the load is removed and when the load is removed First and second storage means which are preset and stored, and control when a predetermined load is applied to the engine when a predetermined load is applied to the engine and when the load is removed. Based on a correction amount calculated from a difference between a first control amount set based on the target rotation speed and a second control amount set based on the control target rotation speed when the load is removed. , Suction in the bypass intake passage And a correcting means for increasing correction or reduction correction air flow rate.

[0007]

According to the above arrangement, two kinds of control amounts having different transition tendencies in accordance with the control target rotational speed, and each of the control amounts in a state where a load is applied and in a state where the load is removed. A first method for obtaining an intake air amount necessary to maintain the target rotation speed corresponding to the target rotation speed.
And the second control amount are set in advance, and the first and second control amounts are set.
Is stored in the storage means. When a predetermined load is applied to the engine and when the load is removed, a first intake air amount required to maintain the control target rotation speed with the load applied is maintained. Is set based on the control target rotational speed, and the second control amount for obtaining the intake air amount necessary to maintain the control target rotational speed in a state where the load is removed is the control target rotational speed. It is set based on the rotation speed. Further, a correction amount of the intake air flow rate is obtained from a difference between the set control amounts, and air having a flow rate based on the correction amount is sucked into the engine. Therefore, even when a load whose load characteristic changes with a change in the rotation speed of the engine is applied to or removed from the engine, the intake air flow rate is corrected by an amount corresponding to the load change. Therefore, the rotation speed of the engine is controlled to be equal to the control target rotation speed.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an idle speed control apparatus for an internal combustion engine according to the present invention;

FIG. 1 is a diagram showing a schematic configuration of a gasoline engine system to which an idle speed control device for an internal combustion engine in this embodiment is applied. The engine 1 as an internal combustion engine takes in outside air from an air cleaner 3 through an intake passage 2 constituting an intake system. In addition, the engine 1 takes in the outside air and
The fuel injected from the injector 4 provided for each cylinder is taken in the vicinity of a. And
A mixture of the taken-in fuel and the outside air is introduced into the combustion chamber 1a through the intake valve 5 provided for each cylinder, and exploded and burned in the combustion chamber 1a to obtain a driving force. Further, the exhaust gas after the explosion and combustion is led out of the combustion chamber 1a to an exhaust passage 7 through which an exhaust manifold for each cylinder is collected via an exhaust valve 6, and is discharged to the outside.

In the middle of the intake passage 2, there is provided a throttle valve 8 which opens and closes in response to operation of an accelerator pedal (not shown). And this throttle valve 8
Is opened and closed, the amount of air taken into the intake passage 2 is adjusted. On the downstream side of the throttle valve 8,
A surge tank 9 for smoothing the pulsation of the intake air is provided.

In the middle of the intake passage 2, there is provided a bypass intake passage 10 for communicating between an upstream side and a downstream side of the throttle valve 8. In the middle of the bypass intake passage 10, a linear solenoid type idle speed valve for adjusting the flow rate of air flowing through the passage 10 is provided.
A control valve (ISCV) 11 is provided. When the throttle valve 8 is closed and the engine 1 is in an idle state, the ISCV 11 is opened and closed under feedback control by duty control, and regulates the air flow rate in the bypass intake passage 10. Thus, the idle speed of the engine 1 is controlled.

Further, the vehicle is provided with a compressor 12 constituting an air conditioner. The compressor 12 is driven and connected to the crankshaft of the engine 1 when the magnet clutch 13 is turned on. A magnet clutch relay 14 is electrically connected to the magnet clutch 13, and the magnet clutch 13 is turned on / off by on / off control of the magnet clutch relay 14, and the air conditioner is driven / stopped (on / off).
Off).

An intake air temperature sensor 21 for detecting the intake air temperature is provided near the air cleaner 3 in the intake passage 2. In the vicinity of the throttle valve 8, a throttle sensor 22 for detecting the opening thereof is provided, and an idle switch 23 for turning on when the throttle valve 8 is fully closed to detect an idle state is provided. I have. Further, the surge tank 9 is provided with an intake pressure sensor 24 which communicates with the tank 9 and detects intake air pressure (intake pressure).

On the other hand, an oxygen sensor 25 for detecting the oxygen concentration in the exhaust gas is provided in the exhaust passage 7. Further, the engine 1 is provided with a water temperature sensor 26 for detecting the temperature of the cooling water.

An ignition signal distributed by a distributor 16 is applied to an ignition plug 15 provided for each cylinder of the engine 1. The distributor 16 distributes the high voltage output from the igniter 17 to the ignition plugs 15 in synchronization with the crank angle of the engine 1. The ignition timing of each ignition plug 15 is the high voltage output timing from the igniter 17. Is determined by

The distributor 16 is provided with a rotation speed sensor 27 for detecting the rotation speed NE (engine rotation speed) NE of the engine 1 from the rotation of a rotor (not shown) built in the distributor 16. Also,
The distributor 16 is also provided with a crank angle sensor 28 that detects a change in the crank angle of the engine 1 at a predetermined rate according to the rotation of the rotor. further,
In this embodiment, a vehicle speed sensor 29 that is attached to a transmission (not shown) and detects a vehicle speed is provided.

Further, a neutral switch 30 is provided at the base end of a shift lever (not shown), and the shift range indicating the position of the shift lever is a neutral range (N range) or a drive range other than the neutral range. (D range).

Further, the engine 1 is provided with a T terminal 31 for diagnosing an abnormal item. This T terminal 3
Numeral 1 is short-circuited at the time of maintenance or the like in order to activate the diagnosis function.

Each of the sensors 21, 22, 24 to
29, by each switch 23, 30 and T terminal 31,
The operating state of the engine 1 and the like are appropriately detected.

Further, each injector 4, ISCV11,
The magnet clutch relay 14 and the igniter 17 are electrically connected to an electronic control unit (hereinafter simply referred to as “ECU”) 41, and the operation timing of the ECU 41 controls their drive timing.

The ECU 41 includes the above-described intake air temperature sensor 21, throttle sensor 22, idle switch 2
3, intake pressure sensor 24, oxygen sensor 25, water temperature sensor 2
6, rotation speed sensor 27, crank angle sensor 28, vehicle speed sensor 29, neutral switch 30, and T terminal 31
And an electric load switch 3 that is connected to another electric load and outputs an ON signal when the electric load is turned on.
2 are connected respectively. Accordingly, the ECU 41 determines that the sensors 21, 22, 24-29 and the switches 2
3, 30, the TSC terminal 31, and the output signal from the electric load switch 32, the injector 4, ISCV11,
The magnet clutch relay 14 and the igniter 17 are suitably controlled.

Next, the configuration of the ECU 41 will be described with reference to the block diagram of FIG. The ECU 41 includes a central processing unit (CPU) 42, a read-only memory (ROM) 43 in which a predetermined control program, a map, and the like are stored in advance, a CPU 42
, A random access memory (RAM) 44 for temporarily storing the calculation results, etc., a backup RAM 45 for storing previously stored data, etc.
6, a logical operation circuit in which the external output circuit 47 and the like are connected by a bus 48.

The external input circuit 46 includes the above-described intake air temperature sensor 21, throttle sensor 22, idle switch 2
3, intake pressure sensor 24, oxygen sensor 25, water temperature sensor 2
6, a rotational speed sensor 27, a crank angle sensor 28, a vehicle speed sensor 29, a neutral switch 30, a T terminal 31, an electric load switch 32, and the like are connected to each other.
Then, the CPU 42 receives the respective sensors 21, 22, 24 to 29, the respective switches 23, 30, and T via the external input circuit 46.
The output signals from the terminal 31 and the electric load switch 32 are read as input values. The CPU 42 suitably controls the injector 4, the ISCV 11, the magnet clutch relay 14, and the igniter 17 connected to the external output circuit 47 based on these input values.

In this embodiment, when the CPU 42 determines that the engine 1 is in an idle state based on the detection result of the idle switch 23, the engine speed NE is controlled to a control target speed (hereinafter referred to as a target speed). The intake air flow rate (total idle-up flow rate) required to converge to NT is calculated, and the ISCV 11 is feedback-controlled based on the calculation result.

Next, among the various processes executed by the ECU 41, a process for calculating the total idle-up flow rate GAISC will be described with reference to the flowchart of FIG.

FIG. 3 is a graph showing a difference I depending on the on / off switching of the air conditioner when the engine 1 is running at a low speed, that is, when the engine 1 is idling.
9 shows a routine for calculating the duty ratio of the SCV 11, which is executed by a periodic interruption every predetermined time.

When the process proceeds to this routine, first, at step 101, the magnet clutch relay 14
It is determined whether or not the air conditioner is on based on the on / off switching of. Then, when the air conditioner is on, in the next step 102, the total idle up flow rate GAISC is calculated.

This total idle-up flow rate GIAS
C is calculated according to the following equation (A). GAISC = GAC + GI + GE + GB (A) Here, GAISC is a total idle-up flow rate, and indicates a final command value for controlling the ISCV11. By adjusting this value, the engine speed can be accurately adjusted. It is controlled. GAC is an air conditioner idle-up correction term, which indicates a correction amount for performing feedback control to the target rotation speed NT when the air conditioner is turned on, and is “0” when the air conditioner is turned off. GI is an idle rotation feedback correction term, and indicates a correction amount for performing feedback control to the target rotation speed NT when the air conditioner is turned off. GE is a D range load correction term, and indicates a correction amount when a D range load is applied. GB is an electric load correction term, and indicates a correction amount when another electric load is applied.

On the other hand, if the air conditioner is off in step 101, the total idle up flow rate GAISC is calculated in step 103 according to the following equation (B).

GAISC = GI + GE + GB (B) That is, the correction amount of the total idle-up flow rate GAISC differs between the case where the air conditioner is turned on and the case where the air conditioner is turned off by the air-conditioner idle-up correction term GAC.

In step 104 following step 102 or step 103, the duty ratio DUT of the ISCV 11 is calculated. This duty ratio DU
As shown in FIG. 10, T is obtained by referring to a map in which the relationship between the duty ratio DUT and the total idle-up flow rate GAISC is predetermined.

Then, in step 105, the ISCV 11 is duty-controlled based on the duty ratio DUT, and the subsequent processing is temporarily terminated. Next, of the various processes executed by the ECU 41 described above, a process for setting a learning target rotation speed serving as an index for setting the target rotation speed NT will be described with reference to a flowchart of a learning routine shown in FIG. .

In this learning routine, first, in step 201, in the condition of the learning mode, that is, in the state where the T terminal 31 is short-circuited at the time of maintenance or the like,
It is determined whether or not all of the conditions for 5 seconds or more after the idle state are satisfied. That is, this routine is executed when substantially all the conditions of the learning mode are satisfied.

In step 201, if all the conditions for the learning mode are not satisfied,
The subsequent processing ends. On the other hand, if it is determined in step 201 that all the requirements for the learning mode are satisfied, the process proceeds to the next step 202.

In step 202, it is determined whether the air conditioner is on. If the air conditioner is on, in the next step 203, it is determined whether or not the vehicle is an AT vehicle. In this embodiment, it is determined whether or not the vehicle is an AT vehicle based on whether the neutral switch 30 has been turned on / off at least once in the past. And if it is not an AT car,
In step 204, the engine speed NE at that time is set as the air conditioner learning speed KGNEAC, and the subsequent processing is temporarily terminated.

If it is determined in step 203 that the vehicle is an AT car, it is determined in step 205 whether or not the shift range at that time is the D range based on a signal from the neutral switch 30. If it is determined that the range is not the D range, in step 204, the air conditioner learning rotation speed KGNEA is performed in the same manner as described above.
C is set, and the subsequent processing is temporarily ended. If it is determined in step 205 that the camera is in the D range, step 20 is executed.
In 6, the engine speed NE at that time is set as the air conditioner drive learning rotation speed KGNEAD,
Thereafter, the processing is temporarily terminated.

On the other hand, if the air conditioner is off in step 202, it is determined in step 207 whether or not the vehicle is an AT vehicle. If the vehicle is not an AT vehicle, in step 208, the engine speed NE at that time is set as the no-load learning rotation speed KGNE, and the subsequent processing is temporarily terminated. If it is determined in step 207 that the vehicle is an AT vehicle, it is determined in step 209 whether the shift range at that time is the D range. If the range is not the D range, in step 208, the no-load learning rotation speed KGNE is set in the same manner as described above, and the subsequent processing is temporarily terminated. If the range is the D range in step 209, the engine speed NE at that time is set as the drive learning rotation speed KGNED in step 210, and the subsequent processing is temporarily terminated.

As described above, the learning rotational speeds KGNEAD, KGNEAC, and KGN under various load conditions are set.
ED and KGNE are set. Note that each of these learning rotation speeds KGNEAD, KGNEAC, KGNED, KGN
E is updated each time the learning mode is established.

Next, each of the learning rotational speeds KGNEAD, KGNEAC, KGNED, KGN set as described above.
A process for setting the target rotation speed NT based on E will be described with reference to the flowchart of FIG.

FIG. 5 shows a calculation routine for setting the target rotation speed NT, which is executed by a periodic interruption every predetermined time. When the process proceeds to this routine, first, in step 301, it is determined whether or not the air conditioner is on. If the air conditioner is on, in step 302, it is determined whether the vehicle is an AT vehicle. If it is not an AT car, step 3
03, the air-conditioner learning rotation speed K previously set
GNEAC is set as the target rotation speed NT, and the subsequent processing is temporarily terminated.

If it is determined in step 302 that the vehicle is an AT vehicle, it is determined in step 304 whether the shift range at that time is the D range. If it is not the D range, step 303 is executed in the same manner as described above.
, The air conditioner learning rotation speed KGNEAC is set as the target rotation speed NT, and the subsequent processing is temporarily terminated. If it is determined in step 304 that the engine is in the D range, in step 305, the previously set air conditioner drive learning rotation speed KGNEAD is set as the target rotation speed NT, and the subsequent processing is temporarily terminated.

On the other hand, if the air conditioner is off in step 301, it is determined in step 306 whether or not the vehicle is an AT vehicle. If the vehicle is not an AT vehicle, in step 307, the previously set no-load learning rotation speed KGNE is set as the target rotation speed NT, and the subsequent processing is temporarily terminated.

If it is determined in step 306 that the vehicle is an AT car, it is determined in step 308 whether the shift range at that time is the D range. If the range is not the D range, the no-load learning rotation speed KGNE is set as the target rotation speed NT in step 307 as described above, and the subsequent processing is temporarily terminated.

If it is determined in step 308 that the engine is in the D range, in step 309, the previously set drive learning rotation speed KGNED is set as the target rotation speed NT, and the subsequent processing is temporarily terminated.

As described above, the target rotation speed NT is set according to the load application and removal conditions such as the on / off state of the air conditioner and the shift range state. Next, a method of calculating each correction term of the above-described total idle-up flow rate GAISC will be described. First, an air conditioner idle-up correction term GA that is corrected when the air conditioner is turned on.
The process for setting C will be described with reference to the flowchart in FIG.

The flowchart of FIG. 6 shows a routine for calculating the air conditioner idle-up correction term GAC, which is executed by a periodic interruption every predetermined time. When the process proceeds to this routine, first, at step 401, it is determined whether or not the air conditioner is on. Then, when the air conditioner is off, in step 402, the count value CNT1 of the counter is reset to "0". However, this counter is incremented for each unit time in another processing routine.

In step 403, an air conditioner learning correction term GACM is calculated. This air conditioner learning correction term GA
The CM refers to a map such as that shown in FIG.
This is set based on the EAC. In step 404, a no-load learning correction term GIDL is calculated. The no-load learning correction term GIDL is set based on the no-load learning rotation speed KGNE with reference to a map as shown in FIG.

In step 405, the air conditioner idle-up correction term GAC is calculated from the difference between the air conditioner learning correction term GACM and the no-load learning rotation speed KGNE calculated in steps 403 and 404. That is, an air conditioner learning correction term GACM, which is a correction term for obtaining an intake air amount required to hold the target rotation speed NT when the air conditioner is turned on, and a target rotation speed NT when the air conditioner is turned off. The air-conditioner idle-up correction term GAC is set based on the difference from the no-load learning correction term GIDL, which is a correction term for obtaining the intake air amount necessary for holding. Then, the subsequent processing ends once.

On the other hand, if the air conditioner is in the ON state in step 401, it is determined in step 406 whether or not the current state is the idle state based on the signal from the idle switch 23. Then, if it is not in the idle state, the subsequent processing is temporarily ended, and if it is in the idle state, the process proceeds to the next step 407.

In step 407, the count value C
It is determined whether or not NT1 is longer than 2 seconds, that is, whether or not more than 2 seconds have elapsed since the idle state. If the count value CNT1 is equal to or less than 2 seconds, the subsequent processing is temporarily terminated. Step 40
In step 7, if the count value CNT1 is larger than 2 seconds, the process proceeds to the next step 408.

In step 408, the engine speed NE is compared with the target speed NT. If the engine rotational speed NE is lower than the target rotational speed NT, in step 409, a value obtained by adding the predetermined amount x to the air conditioner idle up correction term GAC set in the previous control cycle is used as a new air conditioner idle speed. It is set as the up correction term GAC. However, when the count value CNT1 in the previous control cycle is 2 seconds or less, the value calculated in step 405 is directly applied as the air conditioner idle-up correction term GAC. When the engine speed NE is equal to the target speed NT,
The routine proceeds to step 410, where the previous air conditioner idle up correction term GAC is set as it is as the air conditioner idle up correction term GAC. Further, the engine speed N
If E is higher than the target rotation speed NT, step 4
At 11, the previous air conditioner idle-up correction term G
A value obtained by subtracting a predetermined amount x from AC is set as a new air conditioner idle-up correction term GAC. Then, when a new air conditioner idle-up correction term GAC is set in step 409, step 410, or step 411, the subsequent processing is temporarily terminated.

As described above, the air conditioner idle-up correction term GAC when the air conditioner is turned on is set. Next, a process for setting the idle rotation feedback correction term GI will be described with reference to the flowchart of FIG.

FIG. 7 is a flowchart for explaining a routine for calculating the idle rotation feedback correction term GI, which is executed by a periodic interruption every predetermined time. When the process proceeds to this routine, first, at step 501, it is determined whether or not the air conditioner is on. Then, when the air conditioner is off, in step 502, the count value CNT2 by another counter is reset to “0”. However, this counter is also incremented for each unit time by another processing routine, similarly to the above.

Next, in step 503, a predetermined value α set in advance is set as an idle rotation feedback correction term GI, and the subsequent processing is temporarily terminated. On the other hand, if the air conditioner is on in step 501, it is determined in step 504 whether or not the air conditioner is currently idle. If it is not in the idle state, the processes of steps 502 and 503 are executed as described above.

If it is determined in step 504 that the vehicle is in the idle state, it is determined in step 505 whether the count value CNT2 is greater than 2 seconds, that is, more than 2 seconds since the idle state. It is determined whether or not it has elapsed. If the count value CNT2 is equal to or less than 2 seconds, the process of step 503 is executed, and the subsequent process is temporarily terminated. That is, when the air conditioner is in the off state, not in the idle state, or when the idle state has not passed for 2 seconds, the idle rotation feedback correction term GI is uniformly set to the predetermined value α. In step 505, the count value CNT
If 2 is greater than 2 seconds, the process proceeds to step 506.

In step 506, the engine speed NE is compared with the target speed NT. If the engine rotational speed NE is lower than the target rotational speed NT, in step 507, the result of adding the predetermined amount y to the idle rotational feedback correction term GI in the previous control cycle is used as a new idle rotational feedback correction term. Set as GI. However, if the count value CNT2 in the previous control cycle is 2 seconds or less, step 5
The predetermined value α set in 03 is directly applied as the idle rotation feedback correction term GI. If the engine rotation speed NE is equal to the target rotation speed NT, in step 508, the previous idle rotation feedback correction term GI is set as it is as the idle rotation feedback correction term GI. Further, when the engine speed NE is higher than the target speed NT, in step 509, a result obtained by subtracting the predetermined amount y from the previous idle speed feedback correction term GI is set as a new idle speed feedback correction term GI. Then, step 507, step 508 or step 5
At 09, a new idle rotation feedback correction term GI is set, and the subsequent processing is once ended.

As described above, the idle rotation feedback correction term GI when the air conditioner is turned off is set. Next, a process for calculating the D range load correction term GE will be described with reference to the flowchart in FIG.

FIG. 8 is a flowchart for explaining a routine for calculating the D range load correction term GE, which is executed by a periodic interruption every predetermined time. When the process proceeds to this routine, first in step 601, the vehicle
It is determined whether the vehicle is a T car. If the vehicle is not an AT vehicle, in step 602, the D range load correction term GE is set to “0”, and the subsequent processing is temporarily terminated.

On the other hand, if it is determined in step 601 that the vehicle is an AT vehicle, it is determined in step 603 whether or not the current shift range is the D range. And D
If it is not in the range, that is, if it is in the N range, in step 602, the D range load correction term GE is set to “0” in the same manner as described above, and the subsequent processing is temporarily terminated. If it is determined in step 603 that the current shift range is the D range, the process proceeds to step 604.

In step 604, it is determined whether the air conditioner is on. If the air conditioner is on, in step 605, the air conditioner drive learning correction term GACDM is calculated. The air conditioner drive learning correction term GACDM is set based on the air conditioner drive learning rotational speed KGNEAD with reference to a map as shown in FIG. Next, in step 606, the no-load learning correction term GIDL is calculated with reference to the map shown in FIG.

Then, at step 607, a D range load correction term GE is calculated from the difference between the air conditioner drive learning correction term GACDM and the no-load learning correction term GIDL.
That is, the D-range load correction term GE is a correction term for obtaining the amount of intake air required to maintain the target rotation speed when the air conditioner is turned on and the shift range is in the D range. A correction term GACDM;
A no-load learning correction term GIDL, which is a correction term for obtaining an intake air amount necessary to maintain a target rotation speed at no load.
Is determined by the difference between Then, the subsequent processing ends once.

On the other hand, if the air conditioner is off in step 604, a drive learning correction term GDM is calculated in step 608. The drive learning correction term GDM is stored in advance in the ROM 43 in FIG.
Is set based on the drive learning rotational speed KGNED with reference to a map as shown in FIG. Next, in step 609, the no-load learning correction term GIDL is calculated with reference to the map shown in FIG.

Then, in step 610, the D range load correction term GE is calculated from the difference between the drive learning correction term GDM and the no-load learning correction term GIDL. That is, the D range load correction term GE is a drive learning correction term that is a correction term for obtaining an intake air amount necessary to maintain the target rotation speed when the air conditioner is turned off and the shift range is the D range. It is determined by the difference between GDM and a no-load learning correction term GIDL, which is a correction term for obtaining an intake air amount necessary to maintain the target rotation speed at no load. Then, the subsequent processing ends once.

As described above, the D range load correction term GE according to the shift range state is set. Next, a process for calculating the electric load correction term GB will be described with reference to the flowchart in FIG.

FIG. 9 is a flowchart illustrating a routine for calculating the electric load correction term GB, which is executed by a periodic interruption every predetermined time. When the process proceeds to this routine, first, in step 701, it is determined based on a signal from the electric load switch 32 whether or not other electric loads are on. If the electric load is not in the on state, that is, if the electric load is in the off state, in step 702, the electric load correction term GB is set to “0”, and the subsequent processing is temporarily ended. If it is determined in step 701 that the electric load is on, the process proceeds to step 703.

In step 703, it is determined whether the air conditioner is on. If the air conditioner is on, it is determined in step 704 whether the vehicle is an AT vehicle. If the vehicle is not an AT car, in step 705, as shown in FIG. 15, an electric load correction term GB is calculated with reference to a map in which the electric load correction term GB for the air conditioner learning rotation speed KGNEAC is predetermined. Processing is once ended.

On the other hand, if it is determined in step 704 that the vehicle is an AT car, it is determined in step 706 whether the shift range is the D range. If the shift range is not the D range, in step 705, the electric load correction term GB is calculated in the same manner as described above, and the subsequent processing is temporarily terminated. If the shift range is the D range in step 706, the electric load correction term GB for the air conditioner drive learning rotation speed KGNEAD is referenced in step 707 with reference to a map as shown in FIG. Electric load correction term G
B is calculated, and the subsequent processing is temporarily terminated.

On the other hand, if the air conditioner is off in step 703, it is determined in step 708 whether or not the vehicle is an AT vehicle. If the vehicle is not an AT vehicle, the process proceeds to step 709, and as shown in FIG. 17, the electric load correction term GB for the no-load learning rotation speed KGNE is calculated with reference to a predetermined map. Then, the subsequent processing ends once.

If it is determined in step 708 that the vehicle is an AT car, it is determined in step 710 whether the shift range is the D range. If the shift range is not the D range, in step 709, the electric load correction term GB is calculated in the same manner as described above, and the subsequent processing is temporarily terminated. If the shift range is the D range in step 710, the electric load correction term GB with respect to the drive learning rotational speed KGNED is referred to in step 711 by referring to a predetermined map as shown in FIG. Calculate the correction term GB,
Thereafter, the processing is temporarily terminated.

As described above, the electric load correction term GB in the on / off state of the other electric loads is set. That is, when the air conditioner is on and the D range is not set, the map shown in FIG. 15 is referred to. When the air conditioner is turned on and the D range is set, the map shown in FIG. 16 is referred to.
When the air conditioner is off and the D range is not set, the map shown in FIG. 17 is referred.
B is calculated.

Then, the total idle-up flow rate GAISC is determined based on the correction terms GAC, GI, GE, and GB determined as described above, and the duty ratio DU
T is determined, and the ISCV 11 is duty-controlled.

As described in detail above, in this embodiment, the total idle-up flow rate term GAISC is used for the air-conditioner idle-up correction term GAC, the idle rotation feedback correction term GI, the D range load correction term GE, and the electric load correction term GB. Calculated by summation. In addition, each of the correction terms is set to have an appropriate value according to the learning rotation speed that differs depending on various load conditions. Therefore, the amount of intake air required to maintain the target rotation speed NT can be obtained, and as a result, the engine rotation speed can be accurately controlled according to various load conditions.

In this embodiment, step 4 in FIG.
As described in FIG. 03, when the air conditioner is off, the air conditioner idle-up correction term GAC is a correction term for obtaining an intake air amount necessary to maintain the target rotation speed NT when the air conditioner is turned on. The calculation is based on the difference between the learning correction term GACM and the no-load learning correction term GIDL, which is a correction term for obtaining the amount of intake air required to maintain the target rotation speed NT when the air conditioner is turned off. I have. Then, after the air conditioner is turned on, feedback control is performed based on the set value. Therefore, even when the load of the air conditioner varies depending on the engine speed, the actually required intake air flow rate can be accurately corrected in accordance with the load change, and the engine speed NE becomes equal to the target engine speed NT.
Is controlled so that

Further, in this embodiment, as described with reference to FIG. 7, when the air conditioner is off, feedback control of the idle rotation feedback correction term GI is performed. The speed NE is controlled to reach the target rotation speed NT.

In addition, in this embodiment, as described in step 605 of FIG. 8, the D range load correction term G
E is an air conditioner drive learning correction which is a correction term for obtaining an intake air flow rate necessary for maintaining the target rotation speed NT in this state when the shift range is the D range and the air conditioner is on. A term GACDM and a no-load learning correction term G, which is a correction term for obtaining an intake air flow rate necessary to maintain the target rotation speed NT at no load.
It is set by the difference from IDL. Along with this, D
The range load correction term GE is set as follows:
In addition, when the air conditioner is off, a drive learning correction term GDM, which is a correction term for obtaining an intake air flow rate necessary to maintain the target rotation speed NT in this state, is provided.
And a no-load learning correction term GIDL, which is a correction term for obtaining an intake air flow rate necessary to maintain the target rotation speed NT at no load.
Therefore, since the D range load correction term GE can be made to correspond with a change over time, it is possible to correct an actually necessary amount, and therefore, it is necessary to control the engine speed NE to be the target speed NT. Can be. in addition,
In this embodiment, as described with reference to FIG. 9, even when other electric loads are turned on, the electric load correction term GB
Is calculated with reference to the maps shown in FIGS. 15 to 18 under various load conditions. Therefore, an electric load correction term GB corresponding to each load condition is obtained, and the intake air flow rate is corrected. Therefore, the engine speed N
E can be controlled to be the target rotation speed NT.

As described above, according to the engine idle speed control device of this embodiment, the engine speed NE
Even if a load whose load characteristics change with the change of the load is applied or removed, each correction term G can be controlled so that the target rotation speed NT can be controlled according to various load conditions.
AC, GI, GE, and GB are appropriately calculated to determine the total idle-up flow rate GAISC. Therefore, the amount of air that is actually proportional to the change in each load condition is supplied to the engine 1, so that the engine speed NE can be accurately controlled to always be equal to the target speed NT. Therefore, even if a load that changes according to the engine speed NE is applied or removed, it is possible to prevent an overshoot or undershoot of the engine speed from occurring.

The present invention is not limited to the above-described embodiment, and may be implemented as follows, with a part of the configuration being appropriately changed without departing from the spirit of the invention. (1) In the above embodiment, one bypass intake passage 10 is provided, but two or more bypass passages may be provided.

(2) In the above embodiment, the linear solenoid type ISCV 11 provided separately from the throttle valve 8 is provided as the intake air amount adjusting means. However, a step motor type, a rotary solenoid type, and a throttle valve direct acting type are used. May be provided.

[0079]

As described above in detail, according to the present invention, two types of control amounts having different transition tendencies in accordance with the control target rotational speed, and in a state where the load is applied and the load is removed. The first and second control amounts for obtaining the intake air amount necessary to maintain the target rotation speed corresponding to the respective control target rotation speeds in the set state are set in advance, and the first and second control amounts are set. 2 is stored in the storage means. When a predetermined load is applied to the engine and when the load is removed, a first intake air amount required to maintain the control target rotation speed with the load applied is maintained. Is set based on the control target rotational speed, and the second control amount for obtaining the intake air amount necessary to maintain the control target rotational speed in a state where the load is removed is the control target rotational speed. It is set based on the rotation speed. Furthermore,
Since the correction amount of the intake air flow rate is obtained from the difference between the set control amounts, even when a load whose load characteristic changes with a change in the rotation speed of the internal combustion engine is applied or removed, accurate correction is performed. Therefore, an excellent effect is obtained that the overshoot and undershoot of the rotation speed due to the application or removal of the load can be prevented beforehand.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a gasoline engine system to which an idle speed control device for an internal combustion engine is applied in an embodiment embodying the present invention;

FIG. 2 is a block diagram showing a configuration of an ECU in one embodiment.

FIG. 3 is a flowchart illustrating a routine for calculating a total idle-up flow rate at the time of idling executed by an ECU according to one embodiment.

FIG. 4 is a flowchart illustrating a processing routine for setting each learning rotational speed executed by an ECU in one embodiment.

FIG. 5 is a flowchart illustrating a target rotation speed calculation routine executed by an ECU in one embodiment.

FIG. 6 is a flowchart illustrating an air conditioner idle-up correction term calculation routine executed by an ECU in one embodiment.

FIG. 7 is a flowchart illustrating an idle rotation feedback correction term calculation routine executed by an ECU in one embodiment.

FIG. 8 is a flowchart illustrating a process executed by an ECU according to an embodiment;
9 is a flowchart illustrating a range load correction term calculation routine.

FIG. 9 is a flowchart illustrating an electric load correction term calculation routine executed by an ECU in one embodiment.

FIG. 10 is a map showing the relationship between the duty ratio of ISCV and the total idle-up flow rate in one embodiment.

FIG. 11 is a map showing a relationship between an air conditioner learning rotation speed and an air conditioner learning correction term in one embodiment.

FIG. 12 is a map showing a relationship between a no-load learning rotation speed and a no-load learning correction term in one embodiment.

FIG. 13 is a map showing a relationship between an air conditioner drive learning rotational speed and an air conditioner drive learning correction term in one embodiment.

FIG. 14 is a map showing a relationship between a drive learning rotational speed and a drive learning correction term in one embodiment.

FIG. 15 is a map showing a relationship between an electric load correction term and an air conditioner learning rotation speed in one embodiment.

FIG. 16 is a map showing a relationship between an electric load correction term and an air conditioner drive learning rotation speed in one embodiment.

FIG. 17 is a map showing a relationship between an electric load correction term and a no-load learning rotation speed in one embodiment.

FIG. 18 is a map showing a relationship between an electric load correction term and a drive learning rotation speed in one embodiment.

FIG. 19 is a graph showing the relationship between load and engine speed in a conventional example.

FIG. 20 is a graph showing the relationship between the engine rotation speed and the intake air flow rate when there is no load and when there is a load in the conventional example.

[Description of Signs] 1 ... Engine as internal combustion engine, 8 ... Throttle valve, 10 ... Bypass intake passage, 11 ... ISCV, 12 ...
compressor.

Claims (1)

(57) [Claims] An intake of a bypass intake passage which bypasses a throttle valve of an internal combustion engine according to a difference between the detected rotational speed and a control target rotational speed. While controlling the air flow rate so that the engine rotation speed during idling operation becomes equal to the control target rotation speed, the control target rotation speed when a predetermined load is applied to the engine and the load are removed. Control target rotation speed according to the engine state at that time.
In the idle speed control device for an internal combustion engine, which is changed, two types of control amounts each having a different transition tendency according to the control target speed, and when a predetermined load is applied to the engine. The first and second control amounts for obtaining the intake air amount required to maintain the target rotation speed corresponding to the respective control target rotation speeds when the same load is removed are as follows. First and second storage means preset and stored; and control when a predetermined load is applied to the engine when a predetermined load is applied to the engine and when the load is removed. The correction amount calculated from the difference between the first control amount set based on the target rotation speed and the second control amount set based on the control target rotation speed when the load is removed is calculated. Based on the bypass Idle speed control apparatus for an internal combustion engine characterized by comprising a correction means for increasing correction or reduction correction intake air flow rate of the gas passage, a.