JPH1151110A - Control method at the time of idling of variable vibrationproof support device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress excessive rise of an engine speed and prevent the worsening of operation characteristics and a fuel consumption rate by stopping the introduction change-over process of suction negative pressure and atmospheric pressure in a variable vibrationproof support device when the engine speed exceeds a predetermined speed at the time of idling of an internal combustion engine. SOLUTION: Atmospheric pressure is introduced into a variable engine mount 2 when a vacuum switching valve VSV 16 communicates the variable engine mount 2 with a passage 14 and suction negative pressure is introduced therein when the vacuum switching valve VSV 16 communicates a passage 15 by the control of an electronic control unit ECU 31. When an engine speed exceeds a target engine speed by more than a predetermined speed at the time of idling of an internal combustion engine 1, the ECU 31 stops the control of the variable engine mount 2. As a result, atmospheric pressure which flows from the variable engine mount 2 into a surge tank 6 when atmospheric pressure introduction is changed over to negative pressure introduction is decreased, thereby decreasing a fuel injection amount. Consequently, it is possible to prevent excessive rise of an engine speed at the time of idling, namely, the worsening of operation characteristics and a fuel consumption rate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-vibration support device for mounting an internal combustion engine or the like on a vehicle body in an automobile or the like so that vibration of the internal combustion engine is not transmitted to the vehicle body. The present invention relates to a control method at the time of idling of a variable vibration isolating support device that changes vibration isolating characteristics according to a vibration state.

[0002]

2. Description of the Related Art In a vehicle or the like, a vibration-proof bearing device is used for supporting an internal combustion engine, a transmission, or the like so that vibrations are not transmitted to a vehicle body. As this vibration isolator, there is known a liquid filled type vibration isolator described in Japanese Utility Model Laid-Open No. 4-77041.

[0003] The liquid-filled type vibration damping device described in the above publication has a hydraulic fluid chamber in which a part of the chamber wall is formed by a vibration-isolating base made of an elastic body, and a first orifice in the hydraulic fluid chamber. A first compensating liquid chamber formed in communication with a part of the chamber wall of the first diaphragm, a first air chamber separated from the first compensating liquid chamber via the first diaphragm, and a hydraulic fluid; The chamber communicates with the second orifice through a second orifice, and
A second compensating liquid chamber formed by a diaphragm; and a second compensating liquid chamber separated from the second compensating liquid chamber via the second diaphragm.
An air chamber is provided.

The diameter of the second orifice is larger than that of the first orifice so that atmospheric pressure or negative pressure of intake air can be selectively introduced into the second air chamber, and atmospheric pressure is introduced into the first air chamber. It is configured as follows. As a method of introducing the atmospheric pressure and the intake negative pressure into the second air chamber, for example,
An intake negative pressure passage is connected downstream of the throttle valve of the intake passage of the internal combustion engine, and an atmospheric pressure passage is connected upstream of the throttle valve of the intake passage. These passages and the second air chamber are electrically connected. There is known a method of switching between the introduction of atmospheric pressure and the introduction of intake negative pressure to the second air chamber by connecting through a three-way valve and controlling the duty of the three-way valve.

[0005] In the liquid-filled type vibration damping device configured as described above, the atmospheric pressure is always introduced into the first air chamber.
The diaphragm is always movable, whereby the volume of the first compensating liquid chamber is variable. When the atmospheric pressure is introduced into the second air chamber, the second diaphragm also becomes movable, whereby the volume of the second compensating liquid chamber also becomes variable. Since the second orifice is formed larger in diameter than the first orifice, the movement of the liquid at the time of vibration input is mainly performed between the working fluid chamber and the second compensating fluid chamber.

When the atmospheric pressure is introduced into the second air chamber as described above, the liquid in the apparatus moves quickly, so that the pressure in the working fluid chamber does not increase and the dynamic spring constant of the entire apparatus decreases. . As a result, relatively high-frequency vibrations such as idle vibrations can be absorbed and reduced.

Further, when a vacuum pressure is introduced into the second air chamber, the second diaphragm comes into close contact with the wall surface of the second air chamber and its movement is restricted, so that the volume of the second compensation liquid chamber is reduced. It becomes constant, and the movement of the liquid between the working fluid chamber and the second compensation liquid chamber is suppressed. Therefore, the movement of the liquid at the time of the vibration input is mainly performed between the working fluid chamber and the first compensation fluid chamber,
Since the first orifice is formed smaller in diameter than the second orifice, the liquid passing through the first orifice receives a greater resistance than when passing through the second orifice.

As described above, when the vacuum pressure is introduced into the second air chamber, the movement of the liquid in the apparatus is restricted, so that the hydraulic pressure in the working liquid chamber increases and the damping coefficient of the entire apparatus increases. . As a result, relatively low frequency vibrations such as engine shake can be suppressed.

[0009]

By the way, in the above-described liquid-filled type vibration damping device, when the atmospheric pressure is switched from the atmospheric pressure to the negative pressure, the air in the device passes through the intake negative pressure passage and the intake passage. And the intake air amount of the internal combustion engine increases. Then, an increase in the intake air amount is detected by means for detecting the intake air amount of the internal combustion engine, and the fuel injection amount is increased in accordance with the increase amount. As a result, the idle speed of the internal combustion engine increases.

On the other hand, an internal combustion engine has a bypass passage for bypassing an intake passage whose flow rate is controlled by a throttle valve, and a valve (so-called idle speed control valve) for opening and closing this bypass passage. At the time of idling at which the engine is fully closed, an idle speed control device that adjusts the opening of the idle speed control valve and feedback-controls the engine speed so that the idle speed becomes a desired target speed is provided. Are known.

In the internal combustion engine provided with such an idle speed control device, when the idle speed changes due to the operation of the vibration isolator, the opening of the idle speed control valve is adjusted accordingly. In addition, control can be performed so that the engine speed converges to the target speed.

In the idle speed control device, the duty ratio for driving and controlling the idle speed control valve and the amount of air passing through the idle speed control valve are normally in a proportional relationship. Since the relationship is lost, a lower limit guard is provided for the duty ratio.

In this case, the engine speed becomes equal to or higher than the target speed due to the flow of the atmosphere from the vibration isolator to the intake system, and the opening of the idle speed control valve (control value: duty ratio) at that time becomes the lower limit guard. If it has, the opening of the idle speed control valve cannot be further reduced, and the engine speed remains excessively high, which adversely affects the driving characteristics, fuel consumption rate, and the like.

The present invention has been made in view of the above-mentioned problems, and in an internal combustion engine provided with a variable vibration-isolation support device, it is possible to suppress an excessive increase in the engine speed during idling,
It is intended to prevent deterioration of driving characteristics and fuel consumption rate.

[0015]

The present invention employs the following means in order to solve the above-mentioned problems. That is,
The present invention provides an internal combustion engine that selectively introduces an intake negative pressure generated in an intake passage of an internal combustion engine and atmospheric pressure to change a vibration isolation characteristic, and does not transmit vibration of the internal combustion engine to a vehicle body side. A variable vibration-isolating support device, an intake air amount detecting means for detecting the amount of intake air taken into the internal combustion engine, and controlling the intake air amount so that the engine rotation speed becomes a desired target rotation speed when the internal combustion engine is idling. In the internal combustion engine provided with an idle speed control valve, when the engine speed is equal to or higher than a predetermined speed during idling of the internal combustion engine, the variable vibration damping support device switches between the intake negative pressure and the atmospheric pressure. Is stopped.

According to this method, when the atmospheric pressure and the intake negative pressure are selectively introduced by the variable vibration isolating support device, particularly when switching from the introduction of the atmospheric pressure to the introduction of the intake negative pressure, the variable vibration isolator is used. Atmosphere introduced into the vibration isolator is guided to the intake passage by the intake negative pressure, and the intake air amount of the internal combustion engine increases. When the amount of increase in the intake air amount is detected by the intake amount detection means, the fuel injection amount of the internal combustion engine is increased according to the increase amount, and the engine speed increases. At this time, according to the present invention, when the engine speed after the rise becomes equal to or higher than a predetermined speed, the process of switching the introduction of the intake negative pressure and the atmospheric pressure to the variable vibration isolation support device is stopped. The air stops flowing from the air to the intake passage. As a result, the intake air amount detected by the intake air amount detecting means decreases, and the fuel injection amount decreases accordingly.
The engine speed does not drop below the predetermined speed and the engine speed during idling does not increase excessively.

Further, when the control range of the idle speed control valve is set, particularly when the minimum opening of the idle speed control valve is set, the engine speed during idling becomes higher than the target speed. And, when the opening of the idle speed control valve at that time is not more than the minimum opening,
The switching process between the intake negative pressure and the atmospheric pressure in the variable vibration isolation support device may be stopped.

That is, when the engine speed becomes equal to or higher than the target engine speed, the opening of the idle speed control valve is reduced to reduce the engine speed. If the opening is less than the minimum opening, the opening of the idle speed control valve cannot be further reduced, and the engine speed cannot be reduced below the target speed. Therefore, in the present invention, the process of switching the introduction of the intake negative pressure and the atmospheric pressure in the variable vibration isolation support device is stopped, and the flow of the atmosphere from the variable vibration isolation support device to the intake passage is cut off.

In this case, since the intake air amount detected by the intake air amount detecting means decreases, the fuel injection amount is reduced in accordance with the decrease, and the engine speed of the internal combustion engine falls below the target engine speed. Subsequently, since the opening of the idle speed control valve is increased to increase the engine speed to the target speed, the opening of the idle speed control valve becomes larger than the minimum opening, and the idle speed control valve falls within the controllable range. Opening degree. As a result, the idle speed control valve can continue the control so that the engine speed becomes the target speed.

The target rotation speed of the internal combustion engine not provided with the variable vibration isolation support device is set in a rotation range where idle vibration is reduced. In view of the anti-vibration effect of the variable vibration isolator, the rotational speed is set to be lower than that of the internal combustion engine not equipped with the variable vibration isolator. The vibration gets worse.

Therefore, according to the present invention, the target rotation speed may be increased by a predetermined amount when the process of switching the introduction of the atmospheric pressure and the intake negative pressure in the variable vibration isolator is stopped. According to this method, the idle speed of the internal combustion engine is increased to a rotation range where the idle vibration is reduced, and the idle vibration of the internal combustion engine is not transmitted to the vehicle body side.

Further, when the engine rotational speed becomes equal to or higher than a predetermined rotational speed, the process of switching the introduction between the intake negative pressure and the atmospheric pressure in the variable vibration isolator is stopped without stopping the intake negative pressure and the atmospheric pressure. May be reduced by a predetermined amount to reduce the amount of air flowing from the variable vibration isolator to the intake passage.

Further, even when the engine speed is equal to or higher than the target speed and the opening of the idle speed control valve is a controllable minimum opening, the intake negative pressure in the variable vibration isolation support device can be reduced. Without stopping the process of switching the introduction between pressure and atmospheric pressure,
The switching frequency between the intake negative pressure and the atmospheric pressure may be reduced by a predetermined amount to reduce the amount of air flowing from the variable vibration isolator to the intake passage.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an idle control method for a variable vibration isolator according to the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine to which the present invention is applied. The internal combustion engine 1 has a plurality of cylinders 29, and each cylinder 29 has a piston 18 slidable in the axial direction.
The piston 18 is connected to a crankshaft 27 which is an engine output shaft. A combustion chamber 19 is formed above the piston 18, and an ignition plug 20 is attached to face the combustion chamber 19.
The open ends of the intake port 21 and the exhaust port 22
The intake valve 2 is formed to open and close these open ends.
3 and an exhaust valve 24 are provided. The intake valve 23 and the exhaust valve 24 are driven to open and close by an intake camshaft 25 and an exhaust camshaft 26, respectively.

Subsequently, the internal combustion engine 1 has a crank position sensor 28 comprising a timing rotor 28a rotating integrally with a crankshaft 27 and an electromagnetic pickup 28b, and a water temperature for outputting an electric signal corresponding to the temperature of the cooling water. A sensor 30 is attached, and output signals of the crank position sensor 28 and the water temperature sensor 30 are input to an electronic control unit for engine control: ECU 31 via electric wiring.

Next, the intake port 21 is connected to the internal combustion engine 1.
And communicates with the intake branch pipe 5 attached to the intake branch pipe 5.
Is connected to a surge tank 6, and the surge tank 6 is connected to an air cleaner box 9 via an intake pipe 7. In addition, the injection hole is provided in the intake branch pipe 5 with the intake port 2.
1, a fuel injection valve 17 is mounted on the intake pipe 7. The intake pipe 7 is provided with a throttle valve 8 for opening and closing an intake passage in the intake pipe 7 in conjunction with an accelerator pedal (not shown).

Subsequently, an air flow meter 12 which outputs an electric signal in accordance with the mass of air (intake) flowing through the intake pipe 7 and an intake flow rate which corresponds to the temperature of intake air are provided in the intake pipe 7 upstream of the throttle valve 8. Intake air temperature sensor 13 that outputs an electric signal
Are mounted, and these sensors 12 and 13 are connected to the ECU 31 via electric wiring.

Further, a bypass passage 10 for connecting the upstream and downstream of the throttle valve 8 is connected to the intake pipe 7, and the flow passage of fresh air flowing through the bypass passage 10 is adjusted in the bypass passage 10. An idle speed control valve (ISCV) 11 is mounted.

The idle speed control valve 11 comprises a valve element which repeats opening and closing, and a solenoid for driving the valve element, and has a drive pulse having a duty ratio corresponding to the ratio between the fully open time and the fully closed time of the valve element. When a signal is input, the solenoid drives the valve element according to the drive pulse signal to adjust the air flow rate in the bypass passage 10. Thus, the idle speed control valve 11 realizes the idle speed control valve according to the present invention.

Next, the internal combustion engine 1 is supported on the vehicle body side 4 of the automobile by a variable engine mount 2, an engine mount 3, and the like. The variable engine mount 2 is an example of a variable vibration isolation bearing device according to the present invention, and is shown in FIGS.
As shown in the figure, the upper part is formed of an outer cylinder fitting 32, and a disk-shaped rigid body having an outer diameter substantially the same as the inner diameter of the outer cylinder fitting 32. A vibration isolating base 35 which is press-fitted into a space above the partition plate 33 and is fixed to the outer cylinder 32, and an elastic body such as rubber,
A vibration isolating base 36 which is press-fitted into a space below the partition plate 33 and is fixed to the outer cylinder fitting 32.

A space is formed above the partition plate 33 so as to be surrounded by the vibration isolating base 35 and the partition plate 33, and the space is formed by a diaphragm whose peripheral edge is fixed to the partition plate 33. The space portion 37 is divided into a space portion 41 and a space portion 41 by 39, and a liquid is sealed in the space portion 37 (hereinafter, the space portion 37 is referred to as a working fluid chamber 37).

A space 38 is formed below the partition plate 33 of the variable engine mount 2 so as to be surrounded by the vibration-isolating base 36 and the partition plate 33. Is filled with a liquid. And
The space 38 and the space 37 communicate with each other via an orifice 40 formed in the partition plate 33.

Further, the partition plate 33 and the outer cylinder fitting 32 have a communication passage 3 for communicating the space 41 with the outside.
The communication passage 34 communicates with the vacuum switching valve VSV16.

Here, the VSV 16 is connected to the communication passage 34, the passage 14 connected to the intake pipe 7 downstream of the air flow meter 12 and upstream of the throttle valve 8, and to the surge tank 6. A three-way valve connected to the connected passage 15, and communication between the variable engine mount 2 and the passage 14 (blockage of the passage 15).
And a valve body for switching between communication between the variable engine mount 2 and the passage 15 (blockage of the passage 14), and an ECU
And a solenoid for driving the valve element according to a drive current from the solenoid.

When the variable engine mount 2 and the passage 14 are communicated by the VSV 16, FIG.
As shown in the figure, the atmosphere (pressure) flowing in the intake pipe 7 is introduced into the space 41 of the variable engine mount 2, and the volume of the space 41 is increased and at the same time the volume of the working fluid chamber 37 is reduced. As a result, the pressure inside the working fluid chamber 37 is increased.

On the other hand, when the variable engine mount 2 and the passage 15 are communicated with each other by the VSV 16, the negative pressure of the intake air in the surge tank 6 is transferred to the space 41 of the variable engine mount 2 as shown in FIG. Introduced, space part 41
The inside air is sucked out and the diaphragm 39 is separated from the partition plate 33.
And the volume of the space 41 is reduced, and at the same time, the volume of the working fluid chamber 37 is increased. As a result, the pressure in the working fluid chamber 37 is reduced.

Next, the ECU 31 determines the operating state of the internal combustion engine 1 from the output signals from the respective sensors, and then determines the ignition plug 20, the fuel injection valve 17,
Idle speed control valve 11, or V
It controls the SV16.

First, when the internal combustion engine 1 is idling, the ECU 31 repeatedly executes an idle speed control valve feedback control routine at predetermined time intervals to control the idle speed control valve 11. At that time, the ECU 31 calculates a target idle speed corresponding to the operating state of the internal combustion engine 1 and calculates an actual engine speed from an output signal of the crank position sensor 28, and then calculates the target idle speed and the actual idle speed. And the optimum duty ratio is calculated to reduce the deviation between the two. Then, the ECU 31 applies a drive pulse corresponding to the duty ratio to the idle speed control valve 11.

As described above, the ECU 31 performs feedback control of the idle speed control valve 11 so that the actual engine speed becomes the target idle speed. When controlling the VSV 16, the ECU 31 controls the ignition timing of each cylinder 29 (or the timing of the explosion stroke).
Thus, the vibration direction of the internal combustion engine 1 generated by the combustion of the air-fuel mixture in each cylinder 29 is determined, and the VSV 16 is controlled so as to absorb the vibration in the vibration direction. Here, the internal combustion engine 1 uses the crankshaft 27 every time the cylinder 29 explodes.
At this time, a force in the compression direction is applied to the variable engine mount 2. Therefore, the ECU 31 controls the VSV 16 so that the variable engine mount 2 and the passage 15 communicate with each other. As a result, the working fluid chamber 37 is depressurized as described in the above description of FIG. 3, so that the vibration in the compression direction is easily absorbed.

Subsequently, when the internal combustion engine 1 rotates in the opposite direction due to the reaction of the rotation described above, a force in the pulling direction is applied to the variable engine mount 2. Then E
The CU 31 controls the VSV 16 so that the variable engine mount 2 and the passage 14 communicate with each other. As a result, the pressure in the hydraulic fluid chamber 37 is increased as described in the above description of FIG. 2, so that the vibration in the pulling direction is easily absorbed. Hereinafter, the operation and effect of the present embodiment will be described.

First, the ECU 31 repeatedly executes an idle speed control valve feedback control routine as shown in FIG. 4, and performs control so that the idle speed of the internal combustion engine 1 becomes a desired target idle speed.

In the idle speed control valve feedback control routine, the ECU 31
In S401, it is determined whether or not the idling state of the internal combustion engine 1 is stable. Specifically, the ECU 31 determines whether a predetermined time has elapsed since the vehicle speed became zero,
It is determined whether or not the idle state is stable by determining whether or not the cooling water temperature is equal to or higher than a predetermined temperature.

When the ECU 31 determines in step S401 that the idle state is not stable,
When this routine is completed and it is determined in step S401 that the idle state is stable, the process proceeds to step S402.

In step S402, the ECU 31 calculates a target idle speed according to the operating state of the internal combustion engine 1. The parameters for determining the operating state of the internal combustion engine 1 include, for example, a cooling water temperature, a battery voltage, an electric load switch signal of an electronic component such as an air conditioner compressor and a headlight, and the like.

Subsequently, the ECU 31 proceeds to S403,
Based on the output signal of the crank position sensor 28,
An actual engine speed (hereinafter, referred to as an actual engine speed) is calculated. Next, the ECU 31 proceeds to S404, and proceeds to S40.
It is determined whether or not the target idle speed calculated in 2 and S403 matches the actual speed.

If it is determined in step S404 that the target idle speed and the actual speed match, the ECU 31 ends this routine. When it is determined in step S404 that the target idle speed does not match the actual speed, the ECU 31 proceeds to step S405 and determines whether the actual speed is higher than the target idle speed. Is determined.

If it is determined in S405 that the actual rotation speed is higher than the target idle rotation speed, EC
U31 proceeds to S406 and calculates a duty ratio based on the deviation between the target idle speed and the actual speed to reduce the actual speed to the target idle speed.

Subsequently, the ECU 31 proceeds to S407,
It is determined whether the duty ratio calculated in S406 is equal to or smaller than the lower limit guard. If it is determined in S407 that the duty ratio is equal to or smaller than the lower limit guard, the ECU 31 performs a duty ratio lower limit guard process. That is, as shown in FIG. 5, when the duty ratio of the idle speed control valve 11 is equal to or lower than the lower limit guard: DOPMN, the ECU 31 sets the amount of intake air passing through the idle speed control valve 11 to a fixed value: “D”. Set the duty ratio.
The ECU 31 outputs a drive pulse signal corresponding to the duty ratio to the idle speed control valve 1.
1 and the routine is terminated.

If it is determined in step S407 that the duty ratio is larger than the lower limit guard,
31 applies a drive pulse signal corresponding to the duty ratio to the solenoid of the idle speed control valve 11, and terminates this routine.

On the other hand, if it is determined in step S405 that the actual rotation speed is lower than the target idle rotation speed, the ECU 31 proceeds to step S409, and calculates a deviation between the target idle rotation speed and the actual rotation speed. Thus, the duty ratio is calculated to increase the actual rotation speed to the target idle rotation speed. Then, the ECU 31 applies a drive pulse signal corresponding to the calculated duty ratio to the solenoid of the idle speed control valve 11.

When the internal combustion engine 1 is idling, the ECU 31 executes an idle control routine as shown in FIG. This idle control routine is a routine that is repeatedly executed at predetermined time intervals.

In the idle control routine, the ECU 31 first determines in S601 whether the feedback control of the idle speed control valve 11 is being performed, that is, whether the above-described idle speed control valve feedback control routine is being executed. Is determined.

If the ECU 31 determines in step S601 that the idle speed control valve feedback control routine is not being executed, the ECU 31 terminates this routine, and if it determines that the idle speed control valve feedback control routine is being executed, , To S602.

In step S602, the ECU 31 compares the actual engine speed Ne with the target idle speed NRT calculated in the idle speed control valve feedback control routine, and determines that the actual engine speed Ne is the target. It is determined whether or not the engine speed is higher than the idle speed: NRT by a predetermined speed: α or more.

At S602, the actual engine speed:
Ne is a predetermined idle speed from the target idle speed: NRT: α
If it is determined that the value is higher than the above, the ECU 31 proceeds to S603 and determines whether or not the control value (duty ratio): DOP of the idle speed control valve 11 is equal to or less than a preset lower limit: DOPMN, that is, the idle speed control valve. It is determined whether or not the opening of No. 11 is equal to or less than a preset minimum opening.

In step S603, the control value: DOP
Is less than or equal to the lower limit: DOPMN,
The control value (duty ratio) of the VSV 16 is “0%” (atmosphere is introduced into the variable engine mount 2) or “100%”.
% "(Introducing the intake negative pressure into the variable engine mount 2).

When it is determined in S604 that the control value of the VSV 16 is a value other than "0%" or "100%", that is, the atmospheric pressure and the intake negative pressure are alternately introduced into the variable engine mount 2. If the ECU 31 determines that the current state is set, the ECU 31 proceeds to S605, turns on the variable engine mount / idle control suppression flag: XACMDC, and ends this routine.

When it is determined in step S602 that the actual engine speed Ne is not higher than the target idle speed NRT by a predetermined speed α or more, or in step S603, the control value DOP is equal to the lower limit value. : D
If it is determined that it is larger than OPMN, the ECU 31
Proceeding to S606, the variable engine mount / idle control suppression flag: XACMDC is turned off, and normal control of the variable engine mount 2 is permitted.

Further, in S604 described above, the V
When it is determined that the control value of the SV 16 is “0%” or “100%”, the ECU 31 stops the switching control between the introduction of the atmospheric pressure and the introduction of the intake negative pressure in the variable engine mount 2 (atmospheric pressure). The state is fixed to the introduction state or the intake negative pressure introduction state), and this routine ends.

Subsequently, the ECU 31 executes a variable engine mount idle control value update routine as shown in FIG. In this routine, the ECU 31 first determines whether the variable engine mount / idle control suppression flag is on or off (S
701).

If the ECU 31 determines in step S701 that the variable engine mount / idle control suppression flag is in the ON state, the ECU 31 proceeds to step S702, in which a preset map value, that is, the VSV 16 is set to be controlled. The duty ratio is changed to a learning value.

Specifically, the map includes the internal combustion engine 1
Since the duty ratio according to the operating state is set, the ECU 31 determines the operating state at that time, and then reads the duty ratio: DACMi-1 according to the determined operating state from the map. And E
The CU 31 calculates a learning value: DACMi by subtracting a predetermined amount: DDEC from the duty ratio: DACMi-1.

Subsequently, the ECU 31 proceeds to S703,
After performing the guard processing of the learning value: DACMi calculated in S702, the map is accessed, and the duty ratio: DACMi-1 is rewritten to the learning value: DACMi.

In this case, the VSV 16 is determined by the learning value: D
Since it is controlled by the ACMi, the frequency of switching between the introduction of the atmospheric pressure and the introduction of the intake negative pressure in the variable engine mount 2 is reduced, and the space 41 of the variable engine mount 2 is reduced.
The frequency at which the air inside flows into the surge tank 6 decreases, and the amount of air flowing from the variable engine mount 2 to the surge tank 6 decreases. In response to this, the amount of intake air detected by the air flow meter 12 decreases, so that the ECU 31
Reduces the amount of fuel injected from the fuel injection valve 17.
As a result, the engine speed of the internal combustion engine 1 drops below the target idle speed.

As described above, according to the idle control value update routine, the idle speed of the internal combustion engine 1 can be reduced while the control of the variable engine mount 2 is continued. The transmitted idle vibration can be minimized.

On the other hand, if it is determined in step S701 that the variable engine mount / idle control suppression flag is in the off state, the ECU 31 proceeds to step S703 to perform interpolation calculation of the map, and substitutes the calculated value with the learning value. : DACMi.

According to the above-described embodiment, when the internal combustion engine 1 is idling, the engine speed becomes higher than the target idle speed by a predetermined speed or more, and the opening of the idle speed control valve 11 at that time is determined by the ECU 31. When the opening degree is equal to or smaller than the controllable minimum opening degree, the air flowing from the variable engine mount 2 to the surge tank 6 is reduced by reducing the control frequency of the variable engine mount 2, and the intake air amount detected by the air flow meter 12 is reduced. Can be reduced, the fuel injection amount is accordingly reduced, and as a result, the engine speed becomes lower than the predetermined speed.

As a result, an excessive increase in the engine speed at the time of idling is prevented, and the deterioration of the driving characteristics and the fuel consumption rate are prevented. Furthermore, since the control of the variable engine mount 2 can be continued while reducing the control frequency of the variable engine mount 2, the transmission of the idle vibration of the internal combustion engine 1 to the vehicle body can be minimized. .

Further, since the control frequency of the variable engine mount 2 is reduced, the engine speed is reduced.
The ECU 31 controls to increase the opening of the idle speed control valve 11 so that the engine speed becomes the target idle speed. As a result, the opening of the idle speed control valve 11 becomes larger than the minimum opening, and the ECU 31 can continue the feedback control of the idle speed control valve 11. <Other Embodiments> In the above embodiment, the internal combustion engine 1
Although the example in which the control frequency of the variable engine mount 2 is reduced when the idle speed of the engine becomes equal to or higher than the predetermined speed has been described, the control of the variable engine mount 2 may be stopped. In this case, the ECU 31 executes an idle control routine as shown in FIG.

That is, in the idle control routine, the ECU 31 first determines in S801 whether the feedback control of the idle speed control valve 11 is being performed.

If the ECU 31 determines in step S801 that the feedback control of the idle speed control valve 11 is not being performed, the ECU 31 ends this routine. If it determines that the idle speed control valve feedback control routine is being performed, S8
Go to 02.

In step S802, the ECU 31 compares the actual engine speed Ne with the target idle speed NRT calculated in the idle speed control valve feedback control routine, and determines that the actual engine speed Ne is the target. It is determined whether or not the engine speed is higher than the idle speed: NRT by a predetermined speed: α or more.

At S802, the actual engine speed:
Ne is a predetermined idle speed from the target idle speed: NRT: α
If it is determined that the value is higher than the above, the ECU 31 proceeds to S803, and determines whether or not the control value (duty ratio): DOP of the idle speed control valve 11 is equal to or less than a preset lower limit: DOPMN, ie, the idle speed control valve. It is determined whether or not the opening of No. 11 is equal to or less than a preset minimum opening.

In step S803, the control value: DOP
Is less than or equal to the lower limit: DOPMN,
The control value (duty ratio) of the VSV 16 is “0%” (atmosphere is introduced into the variable engine mount 2) or “100%”.
% "(Introducing the intake negative pressure into the variable engine mount 2).

If it is determined in step S804 that the control value of the VSV 16 is "0%" or "100%", the ECU 31 switches the control of the variable engine mount 2 between the introduction of the atmospheric pressure and the introduction of the intake negative pressure. It is determined that it is stopped (fixed to the atmospheric pressure introduction state or the intake negative pressure introduction state), and this routine ends.

In step S804, the VSV1
6 is determined to be a value other than “0%” or “100%”, that is, it is determined that the switching control between the introduction of the atmospheric pressure and the introduction of the intake negative pressure in the variable engine mount 2 is performed. If so, the ECU 31 determines in S805
Then, control of the variable engine mount 2 is prohibited.

Subsequently, the ECU 31 proceeds to S806,
The target idle speed used for feedback control of the idle speed control valve 11 is set higher by a predetermined speed.

As described above, when the introduction switching process between the atmospheric pressure and the intake negative pressure is stopped in the variable engine mount 2, the air does not flow from the variable engine mount 2 to the surge tank 6, and the intake air amount of the internal combustion engine 1 is reduced. That is, the amount of intake air detected by the air flow meter 12 decreases.
At this time, the ECU 31 decreases the fuel injection amount in accordance with the decrease in the intake air amount, so that the engine speed of the internal combustion engine 1 drops below the target idle speed.

When the engine speed has dropped below the target engine speed, the ECU 31 performs control to increase the opening of the idle speed control valve 11 so that the engine speed matches the target idle engine speed. become. As a result, the opening of the idle speed control valve 11 becomes larger than the minimum opening, and the ECU 3
1 can continue the feedback control of the idle speed control valve 11.

Further, the target idle speed of the internal combustion engine supported by the variable engine mount is set to a lower rotation range than that of the internal combustion engine supported by the normal engine mount, in consideration of the vibration damping effect of the variable engine mount. Therefore, when the variable engine mount is stopped, the idle vibration deteriorates.However, by setting the target idle speed at the time when the variable engine mount is stopped to a predetermined high speed, the engine speed of the internal combustion engine is usually reduced. Is substantially the same as the idle speed of the internal combustion engine supported by the engine mount. As a result, even when the variable engine mount 2 is stopped, deterioration of idle vibration is suppressed.

Returning to FIG. 8, in S802, the actual engine speed: Ne is replaced by the target idle speed:
When it is determined that the rotational speed is not higher than NRT by a predetermined number of revolutions: α or in S603, the control value: DOP
Is larger than the lower limit value: DOPMN, the ECU 31 proceeds to S807 and permits the control of the variable engine mount 2. In this case, the ECU 31 continues the normal control of the variable engine mount 2 and the normal control of the idle speed control valve 11.

Therefore, according to the present embodiment, when the engine speed during idling of the internal combustion engine 1 excessively increases,
By stopping the switching control between the introduction of the atmospheric pressure and the introduction of the intake negative pressure in the variable engine mount 2, the engine speed of the internal combustion engine 1 can be reduced, and the operating characteristics are deteriorated due to an excessive increase in the engine speed. The deterioration of the fuel consumption rate is prevented. Further, in the present embodiment, when the control of the variable engine mount 2 is stopped, the target idle speed is set to be higher by a predetermined speed, so that the deterioration of the idle vibration can be prevented.

In the above-described embodiment, the idle speed control valve 11 is taken as an example of the idle speed control valve according to the present invention. However, the idle speed is controlled by the throttle valve 8 when the engine is idle. It may be a mechanism. In short, any configuration is possible as long as the intake air amount of the internal combustion engine 1 can be changed when the internal combustion engine 1 is idle.

[0085]

According to the present invention, when the engine speed becomes equal to or higher than the predetermined speed while the internal combustion engine is idling, the process of switching the introduction of the intake negative pressure and the atmospheric pressure to the variable vibration isolator is stopped. The amount of intake air of the internal combustion engine can be reduced, the engine speed can be reduced, and deterioration of operating characteristics or fuel consumption rate can be prevented.

When the control range of the idle speed control valve is set, particularly when the minimum opening of the idle speed control valve is set, the engine speed during idling becomes higher than the target speed. And, when the opening of the idle speed control valve at that time is not more than the minimum opening,
Since the process of switching the introduction of the intake negative pressure and the atmospheric pressure in the variable vibration isolator is stopped, the amount of intake air of the internal combustion engine is reduced. At this time, the amount of decrease in the intake air amount is detected by the intake amount detection means, and the fuel injection amount is reduced in accordance with the decrease, so that the engine speed falls below the target speed.

Since the opening of the idle speed control valve is increased to increase the engine speed to the target speed, the opening of the idle speed control valve becomes larger than the minimum opening. The opening of the idle speed control valve is an opening within the control range.

Subsequently, when the process of switching the introduction between the atmospheric pressure and the intake negative pressure in the variable vibration isolator is stopped, if the target rotational speed is increased by a predetermined amount, the idle rotational speed of the internal combustion engine becomes Since the idling vibration increases to the rotation speed at which the idling vibration decreases, the vibration of the internal combustion engine is not transmitted to the vehicle body side.

Further, when the engine rotation speed becomes equal to or higher than the predetermined rotation speed, the process of switching the introduction between the intake negative pressure and the atmospheric pressure in the variable vibration isolation support device is not stopped, and the intake negative pressure and the atmospheric pressure are not stopped. If the frequency of introduction switching is reduced by a predetermined amount, the vibration isolating effect of the variable vibration isolating support device can be obtained, and at the same time, the engine speed can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine to which an idle control method of a variable vibration isolating support device according to the present invention is applied;

FIG. 2 is a longitudinal sectional view showing a configuration of a variable engine mount.

FIG. 3 is a diagram showing a state of a variable engine mount when an intake negative pressure is introduced.

FIG. 4 is a flowchart showing an idle speed control valve feedback control routine;

FIG. 5 is a diagram illustrating a lower limit guard process of the idle speed control valve.

FIG. 6 is a flowchart showing an idle control routine.

FIG. 7 is a flowchart showing an idle control value update routine for a variable engine mount.

FIG. 8 is a flowchart illustrating an idle control routine according to another embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Variable engine mount (variable anti-vibration bearing device) 4 ... Body side 10 ... Bypass pipe 11 ... Idle speed control valve (idle speed control valve) 31 ... ECU

Claims (5)

[Claims] 1. An anti-vibration characteristic is changed by selectively introducing an intake negative pressure generated in an intake passage of an internal combustion engine and an atmospheric pressure,
A variable vibration isolating support device for supporting the internal combustion engine so as not to transmit the vibration of the internal combustion engine to the vehicle body side, intake air amount detecting means for detecting an intake air amount sucked into the internal combustion engine, and an engine when the internal combustion engine is idling An idle speed control valve for controlling an intake air amount so that the speed becomes a desired target speed. When the engine speed is equal to or higher than a predetermined speed when the internal combustion engine is idling, the variable vibration isolation An idle control method for a variable vibration-isolation support device, wherein the process of switching the introduction of the intake negative pressure and the atmospheric pressure in the support device is stopped. 2. When the internal combustion engine is idling, when the engine speed is equal to or higher than the target speed and the opening of the idle speed control valve is a controllable minimum opening, the variable vibration isolation is performed. 2. The control method according to claim 1, wherein the switching process between the intake negative pressure and the atmospheric pressure in the support device is stopped. 3. The variable according to claim 1, wherein the target rotation speed is increased by a predetermined amount when the process of switching the introduction between the atmospheric pressure and the intake negative pressure in the variable vibration isolation support device is stopped. An idle control method for the vibration isolator. 4. When the internal combustion engine is idling, when the engine speed is equal to or higher than the predetermined speed, the frequency of switching between the introduction of the intake negative pressure and the atmospheric pressure in the variable vibration isolation support device is reduced by a predetermined amount. 2. The idle control method for a variable vibration isolator according to claim 1, wherein: 5. When the internal combustion engine is idling, when the engine speed is equal to or higher than the target speed and the opening of the idle speed control valve is a controllable minimum opening, the variable vibration isolation is performed. 5. The method according to claim 4, wherein the frequency of switching between the intake negative pressure and the atmospheric pressure in the bearing device is reduced by a predetermined amount.
An idle control method for the variable vibration isolator according to the above.