JP3204163B2 - 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 system for an internal combustion engine, and more particularly to an idle speed control structure suitable for an internal combustion engine provided with a pneumatic operating mechanism such as an active control mount. It is about implementation.

[0002]

2. Description of the Related Art Generally, an internal combustion engine such as an automobile engine has a piston reciprocally movable within a cylinder block, and the piston is connected to a crankshaft (output shaft) of the internal combustion engine via a connecting rod. . The reciprocating movement of the piston is converted into rotation of the crankshaft by the connecting rod. A cylinder head is attached to the cylinder block, and a combustion chamber is provided between the cylinder head and the head of the piston. Further, the cylinder head is provided with an intake passage and an exhaust passage communicating with the combustion chamber, a fuel injection valve for injecting fuel into the combustion chamber, and an ignition plug for igniting a mixed gas in the combustion chamber. Have been.

[0003] In the intake stroke of the internal combustion engine,
While air is sucked into the combustion chamber through the intake passage,
Fuel is injected from the fuel injection valve toward the combustion chamber in an amount corresponding to the amount of intake air into the combustion chamber, and the combustion chamber is filled with a mixed gas comprising the air and the fuel. Thereafter, in the compression stroke of the internal combustion engine, the mixed gas in the combustion chamber is compressed by the movement of the piston. The compressed gas mixture is ignited by the spark plug and explodes, and the explosive force causes the piston to move in the opposite direction to move the internal combustion engine to the explosion stroke. Thereafter, in the exhaust stroke of the internal combustion engine, the exhaust gas in the combustion chamber is discharged to the outside via the exhaust passage by the movement of the piston.

In such an internal combustion engine, a throttle valve for adjusting the amount of air taken into the combustion chamber via an intake passage is provided, and when the valve is fully closed, the internal combustion engine enters an idle state. Become. A bypass passage bypassing the throttle valve is provided in the intake passage, and an idle speed control valve (ISCV) is provided in the passage so as to be adjustable in opening. When the internal combustion engine is idling, most of the air taken into the combustion chamber passes through the bypass passage.
By adjusting the opening degree of V, the amount of air (as a result, the amount of mixed gas) drawn into the combustion chamber is adjusted. By adjusting the intake air amount during idling in this manner, the idle speed of the internal combustion engine is adjusted to be a preset target speed.

The above-mentioned internal combustion engine is mounted on an automobile via an engine mount having a cushioning material. When the engine is mounted, the transmission of vibration from the engine to the vehicle body is prevented by the cushioning material of the engine mount. In addition, since the vibration is not constant in the internal combustion engine, even in such an engine mount, for example, the cushioning material becomes soft at a high rotation speed of the internal combustion engine and becomes hard at a low rotation speed. It is desirable that the hardness of the cushioning material be changed according to the state. Further, since the vibration of the internal combustion engine becomes the largest when the mixed gas explodes, if the buffer material is softened or hardened in accordance with the explosion, the vibration of the internal combustion engine can be suitably suppressed.

Therefore, a so-called active control mount (hereinafter referred to as ACM) that varies the hardness of the cushioning material according to the operating state and vibration state of the internal combustion engine.
Has been proposed. Such an ACM has an air chamber whose volume changes based on the displacement of the diaphragm, and the hardness as a cushioning material is changed by adjusting the amount of air filled in the air chamber.

[0007] The air chamber of the ACM is connected to an atmosphere passage and a negative pressure passage via a vacuum switching valve (VSV). This atmosphere passage communicates with, for example, an upstream side of a throttle valve in an intake passage of an internal combustion engine,
The negative pressure passage communicates with the downstream side of the throttle valve in the intake passage. On the other hand, the VSV is provided with an electromagnetic solenoid, and the duty of the voltage application to the electromagnetic solenoid is controlled so that the amount of air supplied to the air chamber via the atmosphere passage and the VSV, and the VSV and the negative pressure passage from the air chamber are controlled. The amount of air exhausted to the intake passage via is adjusted. That is, by duty-controlling the voltage application of the electromagnetic solenoid, the amount of air filled in the air chamber of the ACM is adjusted, and the hardness of the ACM as a buffer material is adjusted.

In such an ACM, the duty control is performed so that a predetermined amount of air is filled in the air chamber when the mixed gas explodes in the internal combustion engine, and the air is discharged from the air chamber after the explosion. Will be And
By performing this duty control, the ACM becomes soft as a buffer only when the mixed gas explodes, in which the vibration of the internal combustion engine increases, and the vibration of the engine is suitably suppressed.

[0009]

In the internal combustion engine supported by the ACM, air may flow from the VSV side to the negative pressure passage depending on the driving state of the VSV. In this case, the air flowing from the VSV side to the negative pressure passage is
The air flows into the intake passage downstream of the throttle valve, and as a result, the amount of air taken into the combustion chamber increases. Then, when the internal combustion engine is idling, when the intake air amount is increased based on the inflow of air from the negative pressure passage into the intake passage, the fuel injection amount is also increased, and the mixed gas filled in the combustion chamber increases,
The idle speed of the internal combustion engine becomes higher than the target speed. That is, when air flows from the negative pressure passage into the intake passage,
The idle speed cannot be maintained at the target speed.

[0010] The present invention has been made in view of such circumstances, and it is an object of the present invention to reduce the idling speed to the target speed even in an internal combustion engine provided with an air pressure operating mechanism such as an active mount control. It is an object of the present invention to provide an idle speed control device for an internal combustion engine which can be suitably held.

[0011]

In order to achieve the above object, according to the present invention, an intake air amount detecting means for detecting an amount of air taken into an internal combustion engine, and an intake passage when the engine is idling. An idle speed control device for an internal combustion engine that includes intake air amount adjusting means for adjusting the amount of air taken into the engine through the engine and controls the engine speed to a predetermined target speed at the time of idling. There based on supply and discharge of air through the negative pressure passage connected to the throttle valve downstream of the air passage and the intake passage is introduced, oscillating
A pneumatically operated mechanism which operates for suppressing cushioning material to, before
Hardness adjustment as cushioning material of pneumatic operation mechanism is performed
As the air and the air supply and exhaust adjusting means for adjusting the air supply and discharge between the air passage and the negative pressure passage and said pneumatic actuation mechanism, the air supply and exhaust adjusting means from the negative pressure passage to the intake passage And an intake air amount correcting means for correcting an adjustment position of the intake air amount adjusting means in a direction in which the intake air amount is reduced when the air is flowing.

In this structure, the air supply and exhaust between the air passage through which the air is introduced and the negative pressure passage connected to the intake passage of the internal combustion engine and the air pressure operating mechanism are controlled by air supply and exhaust adjustment means. Adjusted. When the air supply / discharge adjustment means is in an adjustment state in which air flows from the negative pressure passage to the intake passage, the adjustment position of the intake air amount adjustment means is in a direction in which the intake air amount of the internal combustion engine is reduced by the intake air amount correction means. Is corrected to Therefore, even if air flows from the negative pressure passage to the intake passage, the amount of air passing through the intake passage does not increase, and an increase in the idling speed of the internal combustion engine based on the increase in the air amount is prevented. The rotation speed can be suitably maintained at the target rotation speed.

[0013] In the second aspect of the present invention, the intake air amount correction means is configured to compensate the intake air amount to the internal combustion engine based on the adjustment position of the air supply / discharge adjustment means. The adjustment position correction amount is determined.

According to this structure, the adjustment position correction amount of the intake air amount adjusting means by the intake air amount correcting means is finely adjusted based on the amount of air flowing from the negative pressure passage to the intake passage. Therefore, when air flows from the negative pressure passage to the intake passage, the idle speed can be more appropriately maintained at the target speed.

According to the third aspect of the present invention, when the adjustment position of the intake air amount adjusting means, which is corrected by the intake air amount correcting means, becomes a position below the lower limit guard value, the negative pressure passage changes to the intake passage. An air supply / discharge correction unit for correcting an adjustment position of the air supply / discharge adjustment unit in a direction in which an amount of air flowing to the air supply unit is reduced.

In this structure, when the adjustment position of the intake air amount adjusting means, which is corrected by the intake air amount correcting means, is below the lower limit guard value, the air supply / discharge correcting means draws air from the negative pressure passage. The adjustment position of the air supply / discharge adjustment means is corrected in the direction in which the amount of air flowing to the passage is reduced. Therefore, in this case, the adjustment position of the intake air amount adjusting means is not excessively adjusted in the intake air amount decreasing direction. If the adjustment position of the air supply / discharge adjustment means is not corrected as described above, the adjustment position of the intake air amount adjustment means is gradually adjusted in the direction of reducing the intake air amount of the internal combustion engine. The amount will reach a minimum. In this state, even if the adjustment position of the intake air amount adjusting means is further adjusted in the intake air amount decreasing direction, the intake air amount does not decrease, so that the adjustment position of the intake air amount adjusting means is the intake air amount. The adjustment is performed up to the end position in the decreasing direction. As a result, when the air stops flowing from the negative pressure passage to the intake passage, the adjustment position of the intake air amount adjusting means is in an excessively adjusted state of the intake air amount decreasing side. Even if the adjustment position of the intake air amount adjusting means is adjusted in the direction of increasing the intake air amount so as to maintain the target rotation speed, the intake air amount cannot be increased immediately, and the idle rotation speed may drop.
Therefore, when the adjustment position of the intake air amount adjusting means is corrected to a position below the lower limit guard value by the intake air amount correcting means, the amount of air flowing from the negative pressure passage to the intake passage is reduced. According to the configuration in which the adjustment position of the supply / discharge adjusting means is corrected, it is possible to suppress the drop in the idle speed.

According to a fourth aspect of the present invention, the air supply / discharge correction means determines an adjustment position correction amount of the air supply / discharge adjustment means such that air is prevented from flowing from the negative pressure passage into the intake passage. To do.

In this configuration, when the adjustment position of the intake air amount adjusting means, which is corrected by the intake air amount correcting means, becomes a position below the lower limit guard value, the air supply / discharge correcting means takes the air from the negative pressure passage through the negative pressure passage. The adjustment position correction amount of the air supply / discharge adjustment means is determined so that the inflow of air into the passage is prohibited. Therefore, in this case, it is possible to more suitably prevent the adjustment position of the intake air amount adjusting means from being excessively adjusted in the intake air amount decreasing direction.

According to the fifth aspect of the present invention, when the adjustment position of the intake air amount adjusting means, which is corrected by the intake air amount correcting means, is below the lower limit guard value, the air supply / discharge adjusting means is turned on by the air supply / discharge adjusting means. On condition that it is in an adjustment state of increasing the amount of air flowing from the negative pressure passage to the intake passage,
There is further provided a lower limit guard value changing means for changing the lower limit guard value of the intake air amount adjusting means to a smaller value.

Generally, the lower limit guard value at the adjustment position of the intake air amount adjusting means is set to be relatively large in consideration of the dimensional tolerance of the intake air amount adjusting means. Even when it is the same as above, it is possible to further reduce the intake air amount by further adjusting the adjustment position of the means in the intake air amount decreasing direction. In this configuration, the lower limit guard value of the intake air amount adjusting means is a guard value changing means, provided that the air supply / discharge adjusting means is in an adjusting state of increasing the amount of air flowing from the negative pressure passage to the intake passage. Will be changed to a smaller value. By changing the lower limit guard value of the intake air amount adjusting means to a smaller value in this way, it is possible to expand the adjustment position region in the intake air amount adjusting means capable of operating the pneumatic operation mechanism.

According to a sixth aspect of the present invention, the adjustment position of the intake air amount adjusting means is learned in accordance with the engine load during idling and the target engine speed.
There is further provided learning inhibition means for inhibiting the learning when the lower guard value is changed by the lower guard value changing means.

According to this configuration, when the lower limit guard value of the intake air amount adjusting unit is changed to a smaller value, the adjustment position control of the intake air amount adjusting unit is performed in the adjustment position region where the control is not originally performed. Therefore, the idle speed may become unstable. As described above, learning of the adjustment position of the intake air amount adjusting means at which the idling rotational speed becomes unstable in accordance with the engine load during idling and the target rotational speed thereof is prohibited by the learning prohibiting means. Therefore,
It is possible to prevent an inappropriate adjustment position of the intake air amount adjusting means from being learned.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) A first embodiment in which the present invention is applied to an in-line four-cylinder automobile engine will be described below with reference to FIGS.

As shown in FIG. 1, a cylinder block 11a of an engine 11 is provided with four pistons (only one is shown in FIG. 1) 12 so as to be reciprocally movable.
Is connected via a connecting rod 13 to a crankshaft 14 which is an output shaft of the engine 11. Piston 12
Is converted into rotation of the crankshaft 14 by the connecting rod 13.

A signal rotor 14a is attached to the crankshaft 14. This signal rotor 14
A plurality of protrusions 14b are provided at equal angles around the axis of the crankshaft 14 on the outer peripheral portion of a. A crank sensor 14c is provided on the side of the signal rotor 14a. And crankshaft 1
4 rotates, and each projection 14b of the signal rotor 14a sequentially passes by the side of the crank sensor 14c, so that the sensor 14c outputs a pulse-like detection signal corresponding to the passage of each projection 14b. Become like

On the other hand, the cylinder block 11a is provided with a water temperature sensor 11b for detecting the temperature of the cooling water in the engine 11. A cylinder head 15 is provided at the upper end of the cylinder block 11a, and a combustion chamber 16 is provided between the cylinder head 15 and the piston 12. An intake port 17 and an exhaust port 18 provided on the cylinder head 15 communicate with the combustion chamber 16. Further, the intake port 17 and the exhaust port 18 are provided with an intake valve 19 and an exhaust valve 20, respectively.

An intake camshaft 21 and an exhaust camshaft 22 for opening and closing the intake valve 19 and the exhaust valve 20 are rotatably supported on the cylinder head 15. These intake and exhaust camshafts 21,
22 is connected to the crankshaft 14 via a timing belt (not shown), and the rotation of the crankshaft 14 is controlled by the belt to intake and exhaust camshafts 21, 22.
To be transmitted to Then, when the intake camshaft 21 rotates, the intake valve 19 is driven to open and close, and the intake port 17 and the combustion chamber 16 are communicated and shut off. When the exhaust camshaft 22 rotates, the exhaust valve 20 is opened and closed to drive the exhaust port 18 and the combustion chamber 1.
6 is communicated / blocked.

In the cylinder head 15, on the side of the exhaust camshaft 22, a cam sensor 22b for detecting a projection 22a provided on the outer peripheral surface of the shaft 22 and outputting a detection signal is provided. Then, when the exhaust camshaft 22 rotates, the projection 22a of the shaft 21 passes by the side of the cam sensor 22b. In this state, a detection signal is output from the cam sensor 22b at predetermined intervals corresponding to the passage of the protrusions 22a.

The intake port 17 and the exhaust port 18 include
An intake pipe 30 and an exhaust pipe 31 are connected to each other.
The interior of the intake pipe 30 and the interior of the intake port 17 include an intake passage 32.
The exhaust pipe 31 and the exhaust port 18 form an exhaust passage 33.

An air flow meter 34 is provided at an upstream end of the intake pipe 30. This air flow meter 34
Detects the amount of air taken into the combustion chamber 16 via the intake passage 32, and generates an output signal corresponding to the detected amount of intake air. On the other hand, a fuel injection valve 50 for injecting fuel into the combustion chamber 16 is provided at a downstream end of the intake pipe 30. When the air in the intake passage 32 is sucked into the combustion chamber 16, the fuel injection valve 50 injects fuel toward the combustion chamber 16 to form a mixed gas including fuel and air.

In the intake passage 32, a throttle valve 46 is provided downstream of the air flow meter 34.
Is provided. The opening of the throttle valve 46 (throttle opening) is adjusted based on the amount of depression of an accelerator pedal 47 (accelerator opening) provided in the interior of the vehicle,
By adjusting the opening of the throttle valve 46, the combustion chamber 16 is controlled.
The amount of air drawn into is adjusted. A throttle sensor 46a is provided near the throttle valve 46. The throttle sensor 46a detects a throttle opening and generates an output signal corresponding to the opening.

Further, a bypass passage 49 is connected to the intake passage 32 so as to bypass the throttle valve 46 and communicate between the upstream side and the downstream side of the throttle valve 46. The bypass passage 49 is provided with a linear solenoid type idle speed control valve (ISCV) 49a for adjusting the flow rate of air flowing through the passage 49. The opening of the ISCV 49a is adjusted based on the duty control of the voltage applied to the electromagnetic solenoid 49b, and the amount of air flowing through the bypass passage 49 (hereinafter referred to as ISCV air) is adjusted by adjusting the opening.

The relationship between the ISCV air amount and the duty ratio is shown in the graph of FIG. As is clear from this graph, when the duty ratio is 20% or more, the ISCV air amount increases in response to the increase in the duty ratio. When the duty ratio is 20% or less, the ISCV air amount becomes the minimum value and becomes constant with respect to the change in the duty ratio. This is ISCV4
9a is because the valve structure is such that the ISCV air amount does not decrease even when the opening degree is reduced due to the duty ratio being 20% or less. Therefore, in the present embodiment, a value of the duty ratio of 20% is set as the lower limit guard value corresponding to the opening of the ISCV 49a.

On the other hand, the combustion chamber 1
An ignition plug 51 for igniting the mixed gas filled in the inside 6 is provided. This spark plug 51
Is a distributor 52 provided in the engine 11.
Through an igniter (not shown). The ignition timing of the ignition plug 51 is determined by the output timing of the high voltage output by the igniter. Therefore, by changing the output timing of the high voltage from the igniter, the ignition timing of the engine 11 can be adjusted.

In such an engine 11, during the intake stroke, the combustion chamber 16
A negative pressure is generated in the internal combustion engine, and air is sucked into the combustion chamber 16 through the intake passage 32 by the negative pressure. Also, the fuel injection valve 5
From 0, an amount of fuel corresponding to the amount of air sucked into the combustion chamber 16 is injected toward the combustion chamber 16, and as a result, the combustion chamber 16 is filled with a mixed gas composed of air and fuel. You.

Thereafter, in the compression stroke of the engine 11, the rising of the piston 12 compresses the mixed gas in the combustion chamber 16. The mixed gas compressed in the combustion chamber 16 is ignited by the ignition plug 51 and explodes, and the explosive force lowers the piston 12 to move the engine 11 to an explosion stroke. By this explosion stroke, the engine 11 obtains the driving force. The mixed gas thus combusted in the combustion chamber 16 is exhausted to the outside through the exhaust passage 33 as exhaust gas by the rise of the piston 12 in the exhaust stroke of the engine 11.

When the engine 11 is idling, the depression amount of the accelerator pedal 47 is "0" and the throttle valve 46 is fully closed, so that most of the air sucked into the combustion chamber 16 is bypassed. It will pass through the passage 49. Therefore, when the engine 11 is in an idle state, the opening degree of the ISCV 49a is adjusted to adjust the amount of air taken into the combustion chamber 16 so that the engine 1
The idle speed of 1 is adjusted.

When the engine 11 constructed as described above is mounted in the engine room of the automobile, the crankshaft 14 of the engine 11 is drivingly connected to the wheels of the automobile via, for example, an automatic transmission (automatic transmission). The machine and wheels are not shown). Also, the engine 11 mounted in the engine room has an active control mount (ACM) that can appropriately change its hardness as its own cushioning material.
It is supported by 61. The detailed structure of the ACM 61 is shown in FIG.

As shown in the figure, the ACM 61 has a cylindrical main body case 62 whose bottom is closed. The main body case 62 is a member (not shown) in the engine room.
Through a vehicle body side bracket 63. The inner bottom of the main body case 62 is filled with a cushioning rubber 64, and the main body case 6 located above the cushioning rubber 64 in the drawing.
An isolation member 65 is fitted in the inside 2.

On the upper surface of the separating member 65 in the figure, a sheet-like diaphragm 66 is provided. The entire edge of the diaphragm 66 is pressed against the isolation member 65 by a fixing ring 66a fitted over the isolation member 65. An air chamber 67 is provided between the diaphragm 66 and the isolation member 65, and a supply / discharge passage 68 connected to the air chamber 67 is provided in the isolation member 65 and the main body case 62. By supplying / discharging air to / from the air chamber 67 via the supply / discharge passage 68, the volume of the air chamber 67 expands / contracts.

Inside the main body case 62, a rubber body 69 is fitted on the upper side of the diaphragm 66 in the drawing. The rubber body 69 is provided with a connector 71 that is connected to an engine-side bracket 70 (FIG. 1) attached to the engine 11. Further, a space between the rubber body 69 and the cushion rubber 64 is partitioned by the separating member 65 into a pair of fluid chambers 72a and 72b. These fluid chambers 72
A and 72b are filled with oil or the like, and the oil or the like communicates through a communication passage (not shown) provided in the separating member 65. Accordingly, when the rubber body 69 is elastically deformed by the vibration of the vehicle body or the engine 11, the fluid chamber 72
Since the volumes of a and 72b change, a fluid such as oil flows between the fluid chambers 72a and 72b via the communication passage.

In the ACM 61 having the above structure, as the amount of air in the air chamber 67 increases, the cushioning material becomes softer, and when the amount of air in the air chamber 67 is "0", the cushioning material becomes the hardest. By adjusting the amount of air inside, the hardness of the ACM 61 as a cushioning material is adjusted. The adjustment of the hardness of the ACM 61 is performed according to the operating state of the engine 11, such as making the ACM 61 soft at the time of high rotation and hardening at the time of low rotation.

In the ACM 61, a predetermined amount of air is normally held in the air chamber 67 when the mixed gas explodes in the combustion chamber 16 of the engine 11, and otherwise, the air is removed from the air chamber 67. Become so. By supplying and discharging the air to and from the air chamber 67, the ACM 61 is used as a buffer when the mixed gas explodes, so that the vibration of the engine 11 caused by the explosion of the mixed gas is appropriately suppressed.

Next, an air supply and discharge mechanism for supplying and discharging air to and from the air chamber 67 of the ACM 61 will be described with reference to FIG. As shown in the figure, the supply / discharge passage 68 of the ACM 61 is connected via a vacuum switching valve (VSV) 73 to
It is connected to the atmosphere passage 74 and the negative pressure passage 75. The atmosphere passage 74 communicates with the intake passage 32 upstream of the throttle valve 46, and the negative pressure passage 75 communicates with the intake passage 3.
2 and communicates with the downstream side of the throttle valve 46. The negative pressure passage 75 is provided with a negative pressure tank 75a.

The VSV 73 includes a valve body 76 and an electromagnetic solenoid 7.
7 is provided. The drive control of the VSV 73 is performed by duty control of voltage application to the electromagnetic solenoid 77. When the duty ratio for the duty control is 0%, the valve body 76 shuts off the supply / discharge passage 68 and the negative pressure passage 75 by the urging force of a coil spring (not shown), It is held at a position communicating with the atmosphere passage 74. On the other hand, when the duty ratio is 100%, the valve
8 and the negative pressure passage 75, and the supply / discharge passage 6
8 and to the position where the air passage 74 is cut off. Also,
If the duty ratio is between 0% and 100%,
The valve body 76 moves to a predetermined position between the two positions according to the duty ratio.

By controlling the drive of the VSV 73, the air in the intake passage 32 is supplied to the air chamber 67 (FIG. 2) of the ACM 61 via the atmosphere passage 74 and the VSV 73.
Alternatively, the air in the air chamber 67 is discharged to the intake passage 32 through the VSV 73 and the negative pressure passage 75. Then, by appropriately supplying and discharging air to and from the air chamber 67 of the ACM 61 and adjusting the amount of air in the air chamber 67, A
The hardness of the CM 61 as a cushioning material is adjusted. Further, the duty control is executed and the electromagnetic solenoid 7 is operated.
7 is alternately performed, and the same duty control is performed in the combustion chamber 1
If the process is performed in accordance with the explosion of the mixed gas in Step 6, the ACM 61 is appropriately softened as a cushioning material at the time of the explosion.

The relationship between the amount of air flowing into the intake passage 32 from the negative pressure passage 75 (hereinafter referred to as ACM exhaust air) and the duty ratio is as shown in the graph of FIG. As is clear from this graph, when the duty ratio is 0% and 100%, the ACM exhaust air amount is “0”. When the duty ratio is a value between 30% and 70%, the ACM exhaust air amount is constant and maximum with respect to a change in the duty ratio. Further, the ACM exhaust air amount increases in response to the increase of the duty ratio when the duty ratio is between 0% and 30%, and increases when the duty ratio is between 70% and 100%. The amount is reduced according to the increase in the duty ratio.

As described above, when the duty ratio is 0% to 100%
The reason why the ACM exhaust air is generated when the value is between is that the valve body 76 is held at a position where the atmosphere passage 74 and the negative pressure passage 75 communicate with each other at the duty ratio. That is, when the atmosphere passage 74 and the negative pressure passage 75 communicate with each other, the atmosphere passage 7 is moved from the intake passage 32 upstream of the throttle valve 46 to the atmosphere passage 7.
4. The valve 46 through the VSV 73 and the negative pressure passage 75
Air flows to the intake passage 32 on the downstream side, and ACM exhaust air is generated.

Next, the electrical configuration of the idle speed control device according to the present embodiment will be described with reference to FIG. This idle speed control device includes an electronic control unit (hereinafter referred to as “ECU”) for controlling the operation state of the engine 11 such as ignition timing control, fuel injection timing control, and fuel injection amount control.
92). This ECU 92 has a ROM
93, CPU 94, RAM 95, and backup RAM
It is configured as a logical operation circuit having 96 or the like.

Here, the ROM 62 is a memory that stores various control programs and maps and the like that are referred to when executing the various control programs.
The arithmetic processing is executed based on various control programs and maps stored in M93. Also, the RAM 95 stores the CPU 9
4 is a memory for temporarily storing the calculation results in step 4, data input from each sensor, and the like.
Is a nonvolatile memory for storing data to be stored when the engine 11 is stopped. And ROM93, CPU
The RAM 94, the RAM 95, and the backup RAM 96 are connected to each other via a bus 97, and are also connected to an external input circuit 98 and an external output circuit 99.

The external input circuit 98 includes a water temperature sensor 11
b, the crank sensor 14c, the cam sensor 22b, the air flow meter 34, the throttle sensor 46a, the vehicle speed sensor 78, the shift position switch 79, and the air conditioner switch 80 are connected. On the other hand, the ISCV 49a, the fuel injection valve 50, and the VSV 73 are connected to the external output circuit 99.

Although not shown in FIG. 1,
The vehicle speed sensor 78 detects the vehicle speed of the vehicle based on the rotation of a gear provided in an automatic transmission (not shown), and outputs a detection signal corresponding to the detected vehicle speed. The shift position switch 79 outputs a position signal corresponding to the switching position of the shift lever in the automatic transmission. Further, the air conditioner switch 80 outputs an on / off signal corresponding to on / off of an air conditioner provided in the automobile.

Next, a procedure for calculating and storing the duty ratio for driving the VSV 73 will be described with reference to FIGS. FIGS. 6 and 7 are flowcharts showing a processing routine for calculating and storing the duty ratio. This processing routine is executed by the ECU 92 at an angle interruption every predetermined crank angle.

In the processing routine, the ECU 92 reads various signals from the sensors and the like as the processing of step S101. Then, the process proceeds to step S102, where EC
U92 determines whether or not the vehicle speed is lower than 50 km / h based on the detection signal from the vehicle speed sensor 78. When it is determined that the vehicle speed is 50 km / h or more, that is, when the vehicle is running at a high speed, the process proceeds to step S103. The ECU 92 executes V
After setting the duty ratio command value for SV73 drive to 0%, the process proceeds to step S104 (FIG. 7).

In step S104, the duty ratio command value ("0%") is stored in the RAM 95, and then stored in the ECU 95.
Reference numeral 92 temporarily ends this processing routine. Thus R
When the duty ratio command value is stored in AM95, the ECU
92 is a VSV 73 based on the Tuty Ratio command value.
The duty control of the voltage application to the electromagnetic solenoid 77 in is performed. Then, as a result of the duty control, air is supplied to the air chamber 67 of the ACM 61 as a cushioning material through the atmosphere passage 74, the VSV 73, and the supply / discharge passage 68.
CM61 is the softest cushioning material and AC
The M exhaust air amount is “0”.

On the other hand, if it is determined in step S102 that the vehicle speed is lower than 50 km / h, that is, if the vehicle is running at a low speed or is stopped, the process proceeds to step S105. The ECU 92 determines whether or not the vehicle speed is equal to or higher than 3 km / h as the process of step S105. When the vehicle speed is 3 km / h or more, that is, when the vehicle is running at a low speed, the process proceeds to step S106. The ECU 92 performs the process of step S106 as follows:
After setting the duty ratio for driving the VSV 73 to 100%, the process proceeds to step S104 (FIG. 7).

After the duty ratio command value (“100%”) is stored in the RAM 95 in step S104,
The CU 92 temporarily ends this processing routine. When the duty ratio command value is stored in the RAM 95 as described above, E
The CU 92 determines the VSV based on the duty ratio command value.
Duty control is applied to the voltage application to the electromagnetic solenoid 77 at 73. Then, as a result of the duty control, A
Air is discharged from the air chamber 67 of the CM 61 through the supply / discharge passage 68, the VSV 73, and the negative pressure passage 74. After the air is completely discharged, the ACM 61 becomes the hardest as a cushioning material, and the ACM discharge air amount is “0”. ".

If it is determined in step S105 that the vehicle speed is lower than 3 km / h, that is, if the vehicle is stopped or running at a low speed, step S105 is executed.
Proceed to 107. The processing after step S107 is particularly suitable for reducing the transmission of idle vibration of the engine 11 to the vehicle body when the vehicle is stopped.
73 is for calculating the drive duty ratio.
The reason why the transmission of the idle vibration of the engine 11 to the vehicle body when the vehicle is stopped is reduced because a person riding the vehicle can easily sense the idle vibration transmitted to the vehicle body. Therefore, by reducing the transmission of the idle vibration to the vehicle body, the riding comfort of the vehicle can be improved.

The ECU 92 determines in step S107 whether the shift lever of the automatic transmission is in the drive range (D range) based on the position signal from the shift position switch 79, that is, the idle vibration of the engine 11. It is determined whether or not is large. If it is determined that the shift lever is not in the D range and idle vibration is not large, step S106 is performed.
When it is determined that the shift lever is in the D range and the idle vibration is large, the process proceeds to step S108.
Proceed to.

The ECU 92 determines in step S108 whether or not the engine speed is smaller than 1000 rpm based on the detection signal from the crank sensor 14c, that is, whether or not the engine speed can be regarded as the idle speed. to decide. And the engine speed is 100
0 rpm or more, that is, the engine 1
If the current engine speed is so high that 1 cannot be considered to be in the idle state, the process proceeds to step S106. If it is determined that the engine speed is smaller than 1000 rpm, that is, if the current engine speed is low enough to be considered that the engine 11 is in the idle state, the process proceeds to step S109 (FIG. 7).

The ECU 92 determines whether or not the temperature of the cooling water of the engine 11 is 70 ° C. or more based on the detection signal from the water temperature sensor 11b as the process of step S109. If the water temperature is equal to or higher than 70 ° C., the process proceeds to step S110. If the water temperature is lower than 70 ° C., the process proceeds to step S111. The ECU 92 determines in step S
110 and S111, the air conditioner switch 80
It is determined whether or not the air conditioner is turned on based on the signal from.

[0062] Then, if YES is determined in the step S110, the process proceeds to a step S112. If NO is determined, the process proceeds to a step S113. If YES is determined in step S111, step S11
Then, if NO is determined, the process proceeds to step S115.
Proceed to.

When the process proceeds to step S112, the map shown in FIG. 8A to FIG.
When the map of FIG. 8A is selected and the process proceeds to step S113, the map of FIG. 8B is selected. When the process proceeds to step S114, the map in FIG. 8C is selected, and when the process proceeds to step S115, the map in FIG.
Map is selected. These maps are for calculating a duty ratio command value for driving the VSV 73 based on the engine speed.

Incidentally, the rate of change of the duty ratio command value with respect to the change of the engine speed is the same in any of the above maps. When the duty ratio is calculated from each map at the same engine speed, FIG.
8 is the largest, and the duty ratios calculated from the maps of FIGS. 8B, 8C, and 8D sequentially decrease. This is because the water temperature state and the air conditioner state are respectively set at step S112,
This is because the idle vibration of the engine 11 becomes smaller sequentially after going through S113, S114, and S115.

After the selection of the map, the ECU 92 calculates the duty ratio command value based on the engine speed with reference to the selected map, as the process of the subsequent step S116. The calculated duty ratio command value is "0
% "And" 100% ", but a value between 0% and 100%. Thereafter, the ECU 92 proceeds to step S1
In step 04, the duty ratio command value calculated as described above is stored in the RAM 95, and then the processing routine is temporarily terminated.

As described above, the duty ratio command value is stored in the RAM 9
5, the ECU 92 controls the electromagnetic solenoid 77 of the VSV 73 based on the duty ratio command value.
Duty control of voltage application to As a result of the duty control, a predetermined amount of air is held in the air chamber 67 of the ACM 61, and the ACM 61 has a predetermined hardness as a cushioning material and generates a predetermined amount of ACM exhaust air.

Next, the driving procedure of the VSV 73 will be described with reference to FIGS. Note that FIG.
10A shows a processing routine for setting the interrupt flag F, and FIG. 10B shows a processing routine for bringing the VSV 73 into the non-driving state. FIG. 11 shows the VSV 73
2 shows a processing routine for controlling the driving of. These processing routines are executed through the ECU 92.

The processing routine shown in FIG. 10A is executed by interruption every time a detection signal is input from the cam sensor 22b. The ECU 92 sets “1” as the interrupt flag F in the RAM 95 in the processing of step S201, and then temporarily ends the processing routine.

On the other hand, the processing routine shown in FIG. 11 is executed by interruption every time a detection signal is input from the crank sensor 14c. In the same processing routine, the ECU 9
2 determines whether or not the interrupt flag F is set to "1" as the process of step S301. If it is determined that “F = 1”, step S
Proceeding to 302, the ECU 92 resets the counter C to "0" and resets the interrupt flag F to "0". If it is determined in step S301 that “F = 1” is not satisfied, the process proceeds to step S303 and the ECU proceeds to step S303.
92 adds “1” to the counter C. Here, the counter C is for detecting a crank angle based on the count value.

The ECU 92 calculates the number of revolutions of the engine 11 based on the detection signal from the crank sensor 14c as the process of the subsequent step S304. Thereafter, the process proceeds to step S305, and the ECU 92 determines whether or not the crankshaft 14 is located at 30 ° CA after the top dead center based on the value of the counter C. Then, step S30
In 5, in the case of NO, this processing routine is temporarily ended, and in the case of YES, the process proceeds to step S 306. EC
U92 performs the processing of step S306 by using the RAM 95
It is determined whether or not the duty ratio command value for driving the VSV 73 stored in is stored as “0%”.

If it is determined that the duty ratio command value for driving the VSV 73 is "0%", the flow proceeds to step S307. The ECU 92 holds the VSV 73 in a non-driving state without applying a voltage to the electromagnetic solenoid 77 of the VSV 73 as a process of step S307, and thereafter ends the processing routine once. If it is determined in step S307 that the duty ratio command value for driving the VSV 73 is not “0%”, the process proceeds to step S308.

The ECU 92 calculates the next interruption time T1 when the processing routine shown in FIG. 10B is executed by time interruption as the processing of step S308. That is, the interruption time T1 is obtained by multiplying the time required for the crankshaft 14 to rotate by 180 ° CA determined from the engine speed by the duty ratio command value for driving the VSV 73, and multiplying the multiplied value by "100". Is divided by the current time (the crankshaft 14 is, for example, 30 ° CA after the top dead center of the piston 12 of the first and fourth cylinders).
At the time of being located at (T). The ECU 92 performs the duty control of the voltage application to the electromagnetic solenoid 77 of the VSV 73 based on the duty ratio command value as the process of the subsequent step S309. After the VSV 73 is driven, the ECU 9
2 temporarily terminates this processing routine.

The processing routine shown in FIG. 10B is executed by interruption every time the interruption time T1 is reached. In the same processing routine, the ECU 92 determines in step S
As the processing of 401, the electromagnetic solenoid 77 of the VSV 73
Is stopped, and the VSV 73 is brought into a non-driving state.

Here, the above steps S308 and S309
(FIG. 11) and step S401 (FIG. 10)
The transition of the driving state of the VSV 73 with time based on the process (b) will be described with reference to the time chart of FIG. As shown in the drawing, for example, when the crankshaft 14 is located at 30 ° CA after the top dead center of the piston 12 of the first and fourth cylinders, the VSV 73 is driven. From this time (the current time T) to the interrupt time T1, the VSV 73 is kept in the driving state. In addition, piston 1 of the first and fourth cylinders
2 when the crank angle is advanced by 180 ° from 30 ° CA after the top dead center, the top dead center 30 of the piston 12 of the third and second cylinders
The crankshaft 14 is located at ° CA. From the time at this time (current time T), the interrupt time T
1 (not shown in FIG. 9), the VSV 73 is kept in the driving state.

The interruption time T1, which is the driving end time of the VSV 73, changes based on the duty ratio command value for driving the VSV 73. For example, when the duty ratio command value is “0%”, when the process of step S308 is executed and the interrupt time T1 is calculated, the interrupt time T1 is the same as the current time T (the time T and the time T1). Is "0"). Therefore, immediately after each piston 12 is located at 30 ° CA after the top dead center, the interruption time T1, which is the drive end time of the VSV 73, comes. Therefore, in this case, even if each piston 12 is positioned at 30 ° CA after the top dead center, the VSV 73 is not driven and remains in a non-driven state.

When the duty ratio command value is, for example, "50%", the process of step S308 is executed and the interrupt time T1 is calculated. 90 °
This is the sum of the time required to proceed to CA. Therefore, when each piston 12 is located at 120 ° CA after the top dead center, the interruption time T1, which is the drive end time of the VSV 73, comes. Therefore, in this case, when each piston 12 is located at 120 ° CA after the top dead center,
The VSV 73 is switched from a driving state to a non-driving state.

Further, when the duty ratio command value is "100
% ", When the processing of step S108 is executed and the interrupt time T1 is calculated, the interrupt time T1 is calculated.
1 indicates that the crankshaft 14 is at 180 ° CA at the current time T.
The time required to proceed is added. for that reason,
The VSV 73 that has been driven at 30 ° CA after the top dead center of the piston 12 of a predetermined cylinder (for example, the first and fourth cylinders)
Means that the crank angle is 2 after top dead center of the piston 12 of the cylinder.
When 10 ° CA is reached, the interruption time T1, which is the drive end time of the VSV 73, comes. However, the above crank angle is different for other cylinders (third and second cylinders).
Since the piston 12 corresponds to 30 ° CA after the top dead center of the piston 12, the VSV 73 does not enter the non-driving state but remains held in the driving state.

By setting the drive period of the VSV 73 as described above, when the duty ratio is larger than “0%” and smaller than “100%”, only when the explosion of the mixed gas occurs in the combustion chamber 16. Air room 67 of ACM61
Air is retained inside. That is, only immediately after the explosion of the mixed gas in which the vibration increases, the hardness of the ACM 61 as a cushioning material becomes soft, so that the vibration caused by the explosion of the mixed gas in each cylinder is appropriately absorbed by the ACM 61, and more suitable during idling. Engine vibration can be reduced.

Next, the driving procedure of the ISCV 49a will be described with reference to FIGS. This FIG.
FIG. 14 is a flowchart showing a processing routine for driving and controlling the ISCV 49a. This processing routine is executed by the ECU 92 at a time interruption of, for example, every 100 ms.

In the processing routine, the ECU 92 determines whether or not the vehicle speed is lower than 3 km / h as the processing of step S501. When it is determined that the vehicle speed is 3 km / h or more, the process proceeds to step S504 (FIG. 13), and when it is determined that the vehicle speed is less than 3 km / h, the process proceeds to step S502.

The ECU 92 determines whether or not the throttle opening TA is equal to or less than 0.5 ° based on the detection signal from the throttle sensor 46a as the process of step S502. When it is determined that the throttle opening TA is not less than 0.5 °, the process proceeds to step S504 (FIG. 13), and when it is determined that the throttle opening TA is less than 0.5 °, step S503 is performed. Proceed to.

The ECU 92 determines whether or not the temperature of the cooling water for the engine 11 is higher than 70 ° C. in the process of step S503. If it is determined that the water temperature is 70 ° C. or lower, the process proceeds to step S504.

The operation state of the vehicle when the process proceeds from step S501 to S504 to step S504 includes, for example, a state in which the vehicle is descending downhill with the accelerator off, or a state immediately after the start of the cold engine 11. .

The ECU 92 calculates the duty ratio command value for driving the ISCV 49a according to the water temperature, the vehicle speed and the engine speed with reference to a map (not shown) as the process of step S504. The map is obtained by an experiment in advance so that a duty ratio command value suitable for the operating state of the automobile and the engine 11 is calculated.
After calculating the duty ratio command value in this way, step S
Proceed to 517.

On the other hand, if it is determined in step S503 that the water temperature is higher than 70 ° C.
Proceed to 505. Steps S505 to S516, which will be described later, show a procedure for performing feedback control so that the actual idle speed of the engine 11 becomes the target speed. By the way, the ECU 92 determines in step 5
In step 05, it is determined whether or not the shift lever of the automatic transmission is in the neutral range (N range). When it is determined that the shift lever is in the N range, the process proceeds to step S506, and when it is determined that the shift lever is not in the N range, the process proceeds to step S507.

The ECU 92 determines in steps S506 and S50
In the process of 7, it is determined whether or not the air conditioner is turned on. If YES is determined in step S506, the process proceeds to step S508, and if NO is determined, the process proceeds to step S509. Step S
If YES is determined in step 507, step S510 is performed.
The process proceeds to step S511 if NO is determined.

In step S508, the ECU 92 sets the idling target rotation speed to 800 rpm, and in step S509, sets the idling target rotation speed to 7 rpm.
Set to 00 rpm. Further, in step S510, the target rotation speed during idling is set to 700 rpm,
In step S511, the target rotation speed during idling is set to 600 rpm.

After setting the idling target rotational speed in any of steps S508 to S511, the flow advances to step S512 (FIG. 13). ECU 92
Determines whether or not the value obtained by subtracting the set target speed from the actual engine speed at the present time is greater than 30 rpm as the process of step S512.
If YES is determined in the step S512, the process proceeds to a step S513 to reduce the duty ratio command value for driving the ISCV 49a by a predetermined amount from the current value and reset it as a new duty ratio command value. If NO is determined in step S512, the process proceeds to step S512.
Proceed to 514.

The ECU 92 determines whether or not the value obtained by subtracting the actual engine speed at the present time from the target engine speed at the time of idling is greater than 30 rpm as the process of step S514. Then, in step S514, Y
If determined to be ES, the process proceeds to step S515, in which the duty ratio command value for driving the ISCV 49a is increased by a predetermined amount from the current value and reset as a new duty ratio command value. If NO is determined in step S514, the process proceeds to step S516. The ECU 92
In step S516, the current ISC
The V49a drive duty ratio command value is reset as a new duty ratio command value and RAM
95 is stored as a duty ratio storage value.

By executing such a storage process, the RAM 95 stores four types of duty ratio storage values. The four types of duty ratio stored values correspond to the case where the shift lever is in the N range and the air conditioner is on (after step S508) and the case where the shift lever is in the N range and the air conditioner is in the N range. What corresponds to the case where it is off (step S50)
9), the one corresponding to the case where the shift lever is not in the N range and the air conditioner is on (the one after step S510), and the one
This corresponds to the case where the air conditioner is not in the range and the air conditioner is off (after step S511).

The above four types of duty ratio stored values are learning values and are used when executing various subsequent controls. It is also used when the shift lever is switched from another range to the N range, from the N range to another range, or when the air conditioner is turned off from on or off to on. You. That is,
When the shift lever or the air conditioner is switched, the target rotation speed at the time of idling is switched, so that the duty ratio command value for driving the ISCV 49a must also be switched instantaneously according to the switching of the target rotation speed. Immediately after such switching of the shift lever and the air conditioner, the ECU 92 stores the duty ratio stored value corresponding to the state after the switching in the RAM 9.
5 and the read duty ratio stored value is used as the duty ratio command value immediately after the switching.

Now, the above steps S513, S515,
After the duty ratio command value for driving the ISCV 49a is newly set in S516, the process proceeds to Step S517. The ECU 92 executes I
A lower limit guard process is performed on the duty ratio command value for driving the SCV 49a. That is, when the duty ratio command value for driving the ISCV 49a when the process proceeds to step S517 is smaller than the lower limit guard value (20% in the present embodiment) corresponding to the opening of the ISCV 49a, the lower limit guard value is set to a new duty. Reset as ratio command value. When the duty ratio command value is larger than the lower limit guard value, the duty ratio command value is not reset as described above.

The ECU 92 determines in the following step S518 (FIG. 14) whether or not the duty ratio command value for driving the VSV 73 obtained by the processing routine shown in FIGS. 6 and 7 is larger than 5%. I do. Then, when it is determined that the above-mentioned duty ratio command value is 5% or less, the process proceeds to step S521, and when it is determined that the value is greater than 5%, the process proceeds to step S519. The ECU 92
In the process of step S519, it is determined whether the duty ratio command value for driving the VSV 73 is smaller than 95%. If it is determined that the duty ratio command value is equal to or more than 95%, the process proceeds to step S521, and
If it is determined that it is smaller than%, step S520
Proceed to.

When the process proceeds to step S520,
Duty ratio command value for VSV73 drive is 5% to 95%
Is taken. When the voltage application to the electromagnetic solenoid 77 of the VSV 73 is duty-controlled based on the duty ratio command value, the ACM 61 is driven such that the ACM exhaust air amount increases as is clear from the graph shown in FIG. The ECU 92 determines in step S5
In the process of 20, the value obtained by subtracting 3% from the current duty ratio command value for driving the ISCV 49a is reset as a new duty ratio command value for driving the ISCV 49a.

The ECU 92 performs an output process of the following step S521 based on the above-mentioned Tuty ratio command value.
After duty control of voltage application to the electromagnetic solenoid 49b of the CV 49a, this processing routine is temporarily terminated.
By performing such processing, when the ACM exhaust air amount is large, the duty ratio command value for driving the ISCV 49a is reduced by 3%, so that the amount of air passing through the intake passage 32 does not increase. This prevents an increase in the idle speed of the engine 11 due to the increase in the air amount.

According to the present embodiment in which the processing described in detail above is performed, when the ACM 61 is driven such that the ACM exhaust air increases, the duty ratio command value for driving the ISCV 49a is reduced by 3%. An increase in the amount of air passing through the intake passage 32 is prevented. Therefore, an increase in the idle speed of the engine 11 due to the increase in the air amount is prevented, and the idle speed can be accurately maintained at the target speed.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. This embodiment is different from the first embodiment only in the processing routine for controlling the drive of the ISCV 49a, and the detailed description of the same parts as the other first embodiments will be omitted.

FIGS. 15 to 17 are flowcharts showing the processing routine of the present embodiment for controlling the drive of the ISCV 49a. The same processing routine is also executed by the ECU 92 by interruption every 100 ms, for example.

In the same processing routine, step S60
1 to S617 (FIGS. 15 and 16) correspond to steps S501 to S517 (FIGS. 12 and 1) in the first embodiment.
Since this is the same as 3), the description is omitted here. By the way, in the same processing routine, when the process proceeds to step S618 (FIG. 17) via step S617, the ECU 92
The correction amount B is calculated from the duty ratio command value for driving the VSV 73 with reference to the map shown in FIG.

The change corresponding to the change in the duty ratio command value for driving the VSV 73 in the correction amount B calculated from the above map is similar to the change in the ACM exhaust air amount with respect to the change in the duty ratio command value shown in FIG. Shows the tendency.
That is, when the duty ratio is 0% and 100%, the correction amount B is “0”. Moreover, the duty ratio is 30% or more.
When the value is between 70%, the correction amount B is constant and maximum with respect to the change in the duty ratio. Further, the correction amount B
Increases when the duty ratio is between 0% and 30%, and increases when the duty ratio is between 70% and 100%. You will lose weight.

After calculating the correction amount B in this manner, the process proceeds to step S619, where the ECU 92 determines whether the current ISC
The value obtained by subtracting the correction amount B from the duty ratio command value for driving the V49a is reset as a new duty ratio command value for driving the ISCV49a. Thereafter, the process proceeds to step S620 where the same processing as step S521 (FIG. 14) of the first embodiment is performed.

In the present embodiment, at step S618, the AC
The correction amount B corresponding to the M exhaust air amount is calculated, and the correction amount B is subtracted from the current duty ratio command value for driving the ISCV 49a in step S619. Therefore, when controlling the ISCV 49a in the closing direction based on the generation of the ACM exhaust air, the control amount can be finely adjusted in accordance with the ACM exhaust air amount. Therefore, AC
When the M exhaust air is generated, the idle rotation speed can be more preferably maintained at the target rotation speed.

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIGS. This embodiment is different from the first embodiment only in a processing routine for calculating and storing a duty ratio command value for driving the VSV 73, and a detailed description of the same parts as the other first embodiments will be omitted. .

FIGS. 19 and 20 are flow charts showing a processing routine of this embodiment for calculating and storing the duty ratio. The processing routine is executed by the ECU 9
2 is executed at an angle interruption every predetermined crank angle.

In the same processing routine, step S70
Steps S1 to S708 are performed in step S10 in the first embodiment.
1 to S108 (FIG. 6), the description is omitted here. Now, in the same processing routine, step S
If YES is determined in step 708, step S709 is performed.
Proceed to. The ECU 92 sets, as the subtraction value A, the value obtained by subtracting the lower limit guard value (20%) corresponding to the opening of the ISCV 49a from the current duty ratio command value for driving the ISCV 49a as the process of step S709. Subsequently, the process proceeds to step S710, where the ECU 92
It is determined whether or not the subtraction value A is 0% or more, that is, whether or not the duty ratio command value obtained by the processing routine (FIGS. 12 to 14) for driving and controlling the ISCV 49a is smaller than the lower limit guard value. .

Then, in step S710, "A
If it is determined that ≧ 0% ”, the process proceeds to step S71.
Go to 1 (FIG. 20). In this processing routine, the processing of steps S711 to S718 is the same as that of steps S109 to S116 (FIG. 7) in the first embodiment.
That is, the air conditioner is turned on when the cooling water temperature of the engine 11 is 70 ° C. or higher, the air conditioner is turned off when the water temperature is 70 ° C. or higher, the air conditioner is turned on when the water temperature is lower than 70 ° C., and the air conditioner is turned off when the water temperature is lower than 70 ° C. The duty ratio command value for the VSV drive is calculated from different maps.

On the other hand, in step S710, “A ≧
If it is determined that it is not “0%”, the process proceeds to step S719, and the ECU 92 sets the duty ratio command value for driving the VSV 73 to 0%. Then, step S704
Proceed to (FIG. 20). In step S719, the VSV 73
By setting the duty ratio command value for driving to 0%, AC
Since the drive of the VSV 73 is controlled so as not to generate the M exhaust air, the ISCV 49a is not excessively controlled in the closing direction.

If the drive control of the VSV 73 is not performed as described above, the ISCV smaller than the lower limit guard value is set.
ISCV4 based on duty ratio command value for 49a drive
The opening of 9a gradually decreases, and finally the ISCV air amount reaches the minimum value. In this state,
Even if the opening of ISCV49a becomes smaller, ISCV
Since the air amount does not decrease, the opening of the ISCV 49a is reduced to the minimum value based on the duty ratio command value. As a result, when the ACM exhaust air amount becomes “0”, the ISCV 49a is in the state of being excessively controlled in the closing direction, so that the ISCV air amount is maintained as usual to maintain the idle speed at the target speed. When increasing the amount, the increase cannot be performed immediately, and the idle speed may drop.

However, in this embodiment, the ISCV 49a
When the duty ratio command value for driving is smaller than the lower limit guard value, the duty ratio command value for VSV73 driving is set to 0%, so that the ACM exhaust air amount becomes “0” and the duty ratio for driving ISCV49a becomes The ratio command value is prevented from becoming smaller than the lower limit guard value. Therefore, it is possible to suppress the drop in the idle speed as described above.

According to the present embodiment in which the processing described in detail above is performed, when the duty ratio command value for driving the ISCV 49a is smaller than the lower limit guard value, the VSV 73 is driven and controlled so that the ACM exhaust air is not generated. . As a result of such control, the duty ratio command value for driving the ISCV 49a is prevented from becoming smaller than the lower limit guard value, and the drop in the idle speed is also suppressed.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described with reference to FIGS. This embodiment is different from the first embodiment in a processing routine for driving and controlling the ISCV 49a.
A processing routine for lowering the lower limit guard value (20%) corresponding to the opening of the CV 49a to a value smaller than usual is added. Here, detailed description of the same portions as those of the first embodiment is omitted.

FIG. 21 is a flowchart showing a processing routine for making the lower limit guard value smaller than usual. This processing routine is executed by the ECU 92 at an angle interruption every predetermined crank angle.

In the same processing routine, the ECU 92 sets “0” in the RAM 95 as the guard flag FG in the processing of step S801. Then, step S8
02, the ECU 92 determines that the current ISCV4
9a drive duty ratio command value is lower limit guard value (20
%) Is determined. When it is determined that the duty ratio command value is equal to or larger than the lower limit guard value, the ECU 92 temporarily ends the processing routine.
If it is determined that the duty ratio command value is smaller than the lower limit guard value, the process proceeds to step S803.

The ECU 92 sets “1” in the RAM 95 as the guard flag FG in step S803. Thereafter, the process proceeds to step S804, where the ECU 92
Determines whether the duty ratio command value for driving the VSV 73 is 5% or more. If it is determined that the duty ratio command value is smaller than 5%, step S is executed.
The process advances to step 806, and if it is determined that the duty ratio is 5% or more, the process advances to step S805.

The ECU 92 determines that the duty ratio command value for driving the ISCV 49a is 9 in step S805.
It is determined whether it is 5% or more. When it is determined that the duty ratio command value is not equal to or more than 95%, the process proceeds to step S807, and when it is determined that the duty ratio command value is 95% or more, the process proceeds to step S806. The ECU 92 resets the lower limit guard value as a new duty ratio command value in the process of step S806.

On the other hand, steps S805 to S8
When the process proceeds to step S07, as the process of step S807, the ECU 92 determines whether the duty ratio command value for driving the ISCV 49a is smaller than a value obtained by subtracting 3% from the lower limit guard value. Then, if NO is determined in the step S807, the ECU 92 temporarily ends the processing routine. If YES is determined, the process proceeds to step S808, where the ECU 92 sets the lower limit guard value at 3%.
After resetting the subtracted value as a new duty ratio command value, the processing routine is temporarily terminated.

By executing the above processing routine, the ISCV 49a is driven under the condition that the driving state of the VSV 73 such that the ACM exhaust air amount increases, that is, the duty ratio command value for driving the VSV 73 is 5% to 95%. The drive duty ratio command value is 3% more than the lower limit guard value.
Only be reduced. The reason why the lower limit guard value of the duty ratio command value can be further reduced as described above is that the lower limit guard value corresponding to the opening of the ISCV 49a is generally set to be larger in consideration of the dimensional tolerance at the time of manufacture in the ISCV 49a. That is because. By changing the lower limit guard value to a value smaller than usual (-3%), the opening area of the ISCV 49a in which the ACM 61 can be operated is expanded.

Next, a procedure for controlling the driving of the ISCV 49a will be described with reference to FIGS. FIG. 22 to FIG. 24
Steps S901 to S92 in the processing routine shown in FIG.
1 is the same as steps S501 to S521 of the first embodiment (FIGS. 12 to 14), and a description thereof will not be repeated.

The difference between the present embodiment and the first embodiment is that the process proceeds to step S923 instead of directly proceeding to step S916 when NO is determined in step S914 (FIG. 23). In the process of step S923, the ECU 92 sets the guard flag FG to “0”.
Is set. Then, when it is determined that the guard flag FG is set to “0”, the process proceeds to step S916 and proceeds to step S91.
Go to 7. If it is determined that the guard flag FG is not set to “0” (FG = “1”), the process proceeds to step S917 without performing the process of step S916.

When the process proceeds to step S916, E
The CU 92 stores the duty ratio command value for driving the ISCV 49a at that time in the RAM 95 as a duty ratio storage value. This duty ratio storage value is a learning value and is used when executing various subsequent controls.

In general, when the lower limit guard value of the duty ratio command value for driving the ISCV 49a is made smaller than usual (FG = “1”), the ISCV 49a controls the opening in the opening region where the control is not originally performed. Therefore, the idle speed may become unstable. However, when the lower guard value is smaller than usual, that is, when the guard flag FG is set to “1”, in the present embodiment,
Since the storage of the duty ratio stored value in the RAM 95 is prohibited by the process of step S923, the improper duty ratio stored value is not stored in the RAM 95.

According to the present embodiment in which the processing described in detail above is performed, the following effects can be obtained. The opening area of the ISCV 49a that can operate the ACM 61 can be expanded.

The storage of an improper duty ratio stored value in the RAM 95 can be prevented. In addition, each of the above embodiments can be modified, for example, as follows.

In the fourth embodiment, the lower limit guard value corresponding to the degree of opening of the ISCV 49a is set to a value smaller by 3% than in the normal state, but the value of 3% may be changed as appropriate.
However, even when changing the lower guard value in this way,
The lower limit guard value deviation after the change is preferably smaller than 3%.

In the third embodiment, when the duty ratio command value for driving the ISCV 49a becomes smaller than the lower limit guard value, the duty ratio command value for driving the VSV 73 is set to 0.
Although set to%, it may be set to 100% instead. As described above, even if the duty ratio command value is set to 100%, the ACM exhaust air amount can be set to “0”, and the same effect as in the third embodiment can be obtained.

In the third embodiment, when the duty ratio command value for driving the ISCV 49a becomes smaller than the lower limit guard value, the duty ratio command value for driving the VSV 73 is set to 0.
%, The ACM exhaust air amount is set to “0”, but the present invention is not limited to this. That is, ISCV4
When the duty ratio command value for the 9a drive becomes smaller than the lower limit guard value, the duty ratio command value for the VSV73 drive may be set to a value such that the ACM exhaust air amount decreases. As a result of such control, the duty ratio command value for driving the ISCV 49a is increased, so that the duty ratio command value is less likely to be smaller than the lower limit guard value.
Therefore, it is possible to prevent the ISCV 49a from being excessively controlled in the closing direction. Further, in such control, since the VSV 73 is not drive-controlled so that the ACM exhaust air amount becomes “0”, it is possible to supply and discharge a little air to and from the ACM 61, and to secure the minimum necessary operation of the ACM 61. You will be able to do it.

In the first embodiment, when ACM exhaust air is generated, the ISCV air amount is reduced by subtracting 3% from the duty ratio command value for driving the ISCV 49a. May be set to a value. Also in this case, it is preferable that the value is not excessively increased.

In the first embodiment, when the duty ratio command value for driving the VSV 73 is 5% to 95%, the ISCV4
Although 3% is subtracted from the duty ratio command value for 9a driving, the present invention is not limited to this. That is, IS
The range of the duty ratio command value for driving the VSV 73 when the duty ratio command value for driving the CV 49a is subtracted by 3% may be changed from the above 5% to 95%. Even in this case, it is preferable not to make the range too narrow.

In the first embodiment, FIGS.
In the drive routine of the ISCV 49a shown in FIG. 5, the control structure is such that the process proceeds from step S504 to step S517.
The control structure may be such that the process proceeds from step 4 to step S521. In this case, when the feedback control for setting the idle speed to the target speed is not performed, that is, when the process proceeds to step S504 in FIG. 13, the duty ratio command value for driving the ISCV 49a becomes 3
% Will not be reduced.

If the duty ratio command value for driving the VSV 73 is, for example, 5 to 95% and a state occurs in which no ACM exhaust air is generated due to a failure of the ACM 61, the control structure of the first embodiment will be described. There is a possibility that the duty ratio command value for driving the ISCV 49a decreases and the engine 11 stops. However, in the above control structure in which the process proceeds from step S504 to step S521, if the feedback control is not performed,
The duty ratio command value for driving the ISCV 49a does not decrease as in the case of the first embodiment. Therefore, the ACM61 is more effective than the control configuration of the first embodiment.
It is easy to avoid stopping the engine 11 due to a failure of the engine.

In the above embodiments, the opening of the ISCV 49a was controlled to adjust the amount of air taken into the combustion chamber 16 during idling. Instead, an electronically controlled throttle valve was employed. The intake air amount during idling may be adjusted by controlling the opening degree.

When such an electronically controlled throttle valve is employed, the throttle valve is connected not to the accelerator pedal 47 but to a step motor, which is opened and closed by the motor. An accelerator sensor is provided in the vicinity of the accelerator pedal, and a detection signal in accordance with the amount of depression of the accelerator pedal 47 by the driver, that is, a detection signal corresponding to the accelerator opening is output to the external input circuit 98 of the ECU 92 from the sensor. The opening of the throttle valve is adjusted by controlling the step motor in accordance with the accelerator opening, the engine speed, and the like.

In the first, second, and third embodiments, the lower limit guard processing of the duty ratio command value for driving the ISCV 49a (steps S517, S617, S917)
After the duty ratio command value is finally set (S
520, S619, and S920). In this case, the duty ratio command value does not fall below the lower limit guard value.

In the above embodiments, the atmosphere passage 74 is communicated with the intake passage 32 upstream of the throttle valve 46. Alternatively, the atmosphere passage 74 may be open to the atmosphere.

In the above embodiments, the VSV 73 is used to supply and exhaust air to and from the air chamber 67 of the ACM 61. However, a valve other than the VSV 73 may be used. In the above embodiments, the present invention is applied to the engine 11 employing the ACM 61, but the present invention is not limited to this. For example, the present invention may be applied to an engine employing a pneumatic operation mechanism such as a brake booster driven by utilizing a negative pressure in the intake passage 32. In this case, the same effects as those of the above embodiments can be obtained.

[0136]

According to the first aspect of the present invention, when the air supply / exhaust adjusting means is in the adjustment state of flowing air from the negative pressure passage to the intake passage, the adjustment position of the intake air amount adjusting means is reduced by the intake air amount. Therefore, the amount of air passing through the intake passage of the internal combustion engine does not increase. Therefore, it is possible to prevent an increase in the idle speed of the internal combustion engine based on the increase in the air amount, and to appropriately maintain the idle speed at the target speed.

According to the second aspect of the invention, the adjustment position correction amount of the intake air amount adjusting means by the intake air amount correcting means can be finely adjusted based on the amount of air flowing from the negative pressure passage to the intake passage. Become like Therefore, when air flows from the negative pressure passage to the intake passage, the idle speed can be more appropriately maintained at the target speed.

According to the third aspect of the invention, when the adjustment position of the intake air amount adjusting means, which is corrected by the intake air amount correcting means, is below the lower limit guard value, the negative pressure is adjusted by the air supply / discharge correcting means. The adjustment position of the air supply / discharge adjustment means is corrected in a direction in which the amount of air flowing from the passage to the intake passage is reduced. Therefore, when the adjustment position of the intake air amount adjustment means is corrected to a position below the lower limit guard value by the intake air amount correction means, the intake air amount adjustment means is not excessively adjusted in the intake air amount decrease direction. Can be prevented.

According to the fourth aspect of the invention, when the adjustment position of the intake air amount adjusting means, which is corrected by the intake air amount correcting means, is below the lower limit guard value, the negative pressure is adjusted by the air supply / discharge correcting means. The adjustment position correction amount of the air supply / discharge adjustment means is determined so that the inflow of air from the passage into the intake passage is prohibited. Therefore, in this case, it is possible to more suitably prevent the adjustment position of the intake air amount adjusting means from being excessively adjusted in the intake air amount decreasing direction.

According to the fifth aspect of the present invention, the lower limit guard of the intake air amount adjusting means is provided on condition that the air supply / exhaust adjusting means is in the adjusting state of increasing the amount of air flowing from the negative pressure passage to the intake passage. The value is changed to a smaller value by the guard value changing means. The reason that the lower limit guard value of the intake air amount adjusting means can be changed to a smaller value as described above is that the lower limit guard value is generally set to be relatively large in consideration of the dimensional tolerance of the intake air amount adjusting means. Because it is. Then, by changing the lower limit guard value to a smaller value as described above, it is possible to expand the adjustment position region in the intake air amount adjustment means that can operate the pneumatic operation mechanism.

According to the invention, when the lower limit guard value of the intake air amount adjusting means is changed to a smaller value, the control of the intake air amount adjusting means in the adjustment position region where control is not originally performed is performed. Since the adjustment position control is performed, the idle speed may become unstable. Since the adjustment position of the intake air amount adjusting means at which the idling rotational speed becomes unstable is prohibited from being learned, an inappropriate adjustment for use in controlling the adjustment position of the intake air amount adjusting means is made. The position can be prevented from being learned.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an overall configuration of an engine to which an idle speed control device according to a first embodiment is applied.

FIG. 2 is a sectional view showing an internal structure of an active control mount.

FIG. 3 is a block diagram showing an electrical configuration of the idle speed control device of the embodiment.

FIG. 4 is a graph showing a relationship between a duty ratio for VSV driving and an ACM exhaust air amount.

FIG. 5 is a graph showing a relationship between an ISCV driving duty ratio and an ISCV air amount.

FIG. 6 is a flowchart illustrating a procedure for calculating and storing a duty ratio command value for VSV drive according to the first embodiment.

FIG. 7 is a flowchart illustrating a procedure for calculating and storing a duty ratio command value for VSV drive according to the first embodiment.

FIG. 8 is a map referred to when calculating a duty ratio command value for VSV driving.

FIG. 9 is a time chart illustrating an example of a VSV driving mode.

FIG. 10 is a flowchart illustrating a VSV drive control procedure;

FIG. 11 is a flowchart illustrating a VSV drive control procedure.

FIG. 12 is a flowchart illustrating a drive control procedure of the ISCV according to the first embodiment.

FIG. 13 is a flowchart illustrating a drive control procedure of the ISCV according to the first embodiment.

FIG. 14 is a flowchart illustrating a drive control procedure of the ISCV according to the first embodiment.

FIG. 15 is a flowchart illustrating a drive control procedure of the ISCV according to the second embodiment.

FIG. 16 is a flowchart illustrating a drive control procedure of the ISCV according to the second embodiment.

FIG. 17 is a flowchart illustrating a drive control procedure of the ISCV according to the second embodiment.

FIG. 18 is a map referred to when calculating a correction amount of a duty ratio command value for ISCV driving in the second embodiment.

FIG. 19 is a flowchart illustrating a procedure for calculating and storing a duty ratio command value for VSV drive according to the third embodiment.

FIG. 20 is a flowchart illustrating a procedure for calculating and storing a duty ratio command value for VSV drive according to the third embodiment.

FIG. 21 is a flowchart illustrating a procedure for setting an ISCV lower limit guard value according to the fourth embodiment;

FIG. 22 is a flowchart illustrating a drive control procedure of an ISCV according to a fourth embodiment.

FIG. 23 is a flowchart illustrating a drive control procedure of the ISCV according to the fourth embodiment.

FIG. 24 is a flowchart illustrating a drive control procedure of the ISCV according to the fourth embodiment.

[Explanation of symbols]

11 engine, 16 combustion chamber, 32 intake passage, 34
... air flow meter, 46 ... throttle valve, 49a
… Idle speed control valve (ISCV),
49b: electromagnetic solenoid, 61: active control mount (ACM), 73: vacuum switching valve (VSV), 74: atmosphere passage, 75: negative pressure passage,
92: electronic control unit (ECU), 95: RAM.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification code FI F02D 41/16 F02D 41/16 P F16F 13/26 F16F 13/00 630D (56) References JP-A-2-308942 (JP, A) JP-A-4-314943 (JP, A) JP-A-5-139165 (JP, A) JP-A-8-165970 (JP, A) JP-A-5-306728 (JP, A) −149543 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 41/00-41/40 F02D 9/00-11/10 F02D 29/04 B60K 5/12 F16F 13 / 00

Claims (6)

(57) [Claims] 1. An intake air amount detection means for detecting an amount of air taken into an internal combustion engine, and an intake air amount adjustment device for adjusting an amount of air taken into the engine via an intake passage when the engine is idling. Means for controlling the engine speed at the time of idling to a predetermined target engine speed, comprising: a negative air passage connected to an air passage through which air is introduced and a throttle valve downstream of the intake passage. Based on the supply and exhaust of air through the pressure passage, a pneumatic operating mechanism that operates as a buffer that suppresses vibration and a hardness adjustment of the pneumatic operating mechanism as a buffer are performed.
So that, the air supply and exhaust adjusting means for adjusting the air supply and discharge between the air passage and the negative pressure passage and said pneumatic actuating mechanism, to the intake passage air supply and exhaust adjusting means from the negative pressure passage An intake air amount correction unit that corrects an adjustment position of the intake air amount adjustment unit in a direction in which the amount of intake air is reduced when the air is adjusted to flow. Idle speed control device. 2. The intake air amount correction means determines an adjustment position correction amount of the intake air amount adjustment means in such a manner that the intake air amount to the internal combustion engine can be compensated based on the adjustment position of the air supply / discharge adjustment means. 2. The idle speed control device for an internal combustion engine according to claim 1, wherein: 3. The idle speed control device for an internal combustion engine according to claim 1, wherein an adjustment position of said intake air amount adjusting means, which is corrected by said intake air amount correcting means, is below a lower limit guard value. An air supply / discharge correction unit for correcting an adjustment position of the air supply / discharge adjustment unit in a direction in which an amount of air flowing from the negative pressure passage to the intake passage is reduced. Idle speed control device. 4. The air supply / discharge correction means determines an adjustment position correction amount of the air supply / discharge adjustment means such that the inflow of air from the negative pressure passage into the intake passage is prohibited. 3. The idle speed control device for an internal combustion engine according to claim 3. 5. The idle speed control device for an internal combustion engine according to claim 1, wherein an adjustment position of said intake air amount adjusting means, which is corrected by said intake air amount correcting means, is below a lower limit guard value. The lower limit guard value of the intake air amount adjusting unit is reduced to a smaller value on condition that the air supply / exhaust adjusting unit is in an adjusting state of increasing the amount of air flowing from the negative pressure passage to the intake passage. An idle speed control device for an internal combustion engine, further comprising a lower limit guard value changing means for changing the guard value. 6. An idle speed control apparatus for an internal combustion engine according to claim 5, wherein an adjustment position of said intake air amount adjusting means is learned according to an engine load during idling and a target speed thereof. An idling speed control device for an internal combustion engine, further comprising learning inhibition means for inhibiting the learning when the lower limit guard value is changed by the lower limit guard value changing means.