JP2001221108A - Exhaust recirculation control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust recirculation control device for an internal combustion engine enabling both of preventing the collision between a valve element and a valve seat caused by vibration of the valve element in an exhaust recirculation control valve, and improving the emission performance of the internal combustion engine at high-grade. SOLUTION: A control computer 41 calculates a target opening on the basis of an operating state of an internal combustion engine 101, and controls an exhaust recirculation control valve 12 at the target opening. The control computer 41 calculates a collision opening area where vibration is produced on the valve element 27 of the exhaust recirculation control valve 12 and the valve element 27 intermittently collides with the valve seat 28 due to the vibration and corrects the target opening to fully closing when the target opening is within the collision opening area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas recirculation control device for an internal combustion engine for recirculating a part of exhaust gas flowing through an exhaust passage to an intake passage.

[0002]

2. Description of the Related Art Conventionally, it has been proposed to provide an internal combustion engine with an exhaust gas recirculation control device in order to improve the emission characteristics of the internal combustion engine. The exhaust gas recirculation control device includes an exhaust gas recirculation control valve between the exhaust passage and the intake passage of the internal combustion engine. The exhaust gas recirculation control valve is configured to control a conduction state between an exhaust passage and an intake passage of the internal combustion engine by moving a valve body toward and away from a valve seat.

The amount of contact and separation of the valve body with respect to the valve seat, that is, the opening of the exhaust gas recirculation control valve, is adjusted in accordance with the operating condition of the internal combustion engine. Refluxed to The exhaust gas recirculated to the intake passage is drawn into the combustion chamber of the internal combustion engine. By the introduction of the exhaust gas, the combustion temperature in the combustion chamber is reduced, and N 2
Ox (nitrogen oxide) generation is suppressed, and the emission characteristics of the internal combustion engine are improved.

[0004]

However, depending on the operation state of the internal combustion engine, the cycle of the pressure pulsation of the exhaust gas and the natural frequency of the valve element in the exhaust gas recirculation control valve coincide with each other, and resonance oscillation occurs in the valve element. May occur. When resonance vibration occurs in the valve body, the valve body intermittently collides with the valve seat to generate abnormal noise and vibration, or the valve body and the valve seat may be worn.

In order to solve such a problem, it is conceivable to employ, for example, a technique disclosed in Japanese Patent Application Laid-Open No. 10-9064. The technique of this publication discloses that when the internal combustion engine is in an operating state in which resonance vibration is applied to the valve body of the exhaust gas recirculation control valve, the valve body is seated on the valve seat, in other words, the exhaust gas recirculation control valve is forcibly forced. The valve is fully closed to suppress the resonance vibration of the valve body.

[0006] However, even if the valve body of the exhaust gas recirculation control valve resonates and vibrates due to the pressure pulsation of the exhaust gas, the phenomenon that the valve body intermittently collides with the valve seat does not necessarily occur in all cases. In other words, if the vibration width of the valve body is small enough not to interfere with the valve seat even if the valve body resonates and vibrates, from a different perspective, the valve body is more resilient to the valve seat than the vibration width of the resonance vibrating valve body. If the valve is positioned at a distance, the valve will not collide with the valve seat even if resonance vibration occurs in the valve. For this reason, if the technique disclosed in Japanese Patent Application Laid-Open No. 10-9064 is adopted, the exhaust gas is unnecessarily introduced into the intake passage even under the situation where the valve body does not intermittently collide with the valve seat. Is stopped, and during this stop period, the emission characteristics of the internal combustion engine cannot be improved.

SUMMARY OF THE INVENTION It is an object of the present invention to achieve, at a high level, both the prevention of collision between a valve body and a valve seat based on the vibration of the valve body in an exhaust gas recirculation control valve and the improvement of emission characteristics of an internal combustion engine. An object of the present invention is to provide a possible exhaust gas recirculation control device for an internal combustion engine.

[0008]

The means for achieving the above object and the effects thereof will be described below. The invention according to claim 1 calculates, based on an operation state of the internal combustion engine, a collision opening region in which the valve body of the exhaust gas recirculation control valve is in a state where the valve body intermittently collides with a valve seat due to vibration generated in the valve body, When the target opening is within the calculated collision opening area,
An exhaust gas recirculation control device for an internal combustion engine, wherein the target opening is corrected to a retreat opening that does not cause intermittent collision between a valve body and a valve seat.

In this configuration, even if the internal combustion engine is in an operating state in which the valve body of the exhaust gas recirculation control valve causes vibration, the target opening is corrected to the retreat opening in all cases. is not. That is, if the target opening is out of the collision opening range, it is determined that the valve body does not collide with the valve seat even if it vibrates, and the target opening of the exhaust gas recirculation control valve is maintained as it is. Accordingly, Japanese Patent Application Laid-Open No. 10-9064
Unnecessary exhaust gas as compared with the technology disclosed in Japanese Unexamined Patent Publication (Kokai) No. 7-216 (where the exhaust gas recirculation control valve is completely closed in an operating state where the internal combustion engine generates vibrations in the valve body). Stop of the recirculation to the intake passage can be suppressed. As a result, intermittent collision between the valve body and the valve seat based on the vibration of the valve body can be prevented, and the emission characteristics of the internal combustion engine can be improved at a high level.

According to a second aspect of the present invention, in the first aspect of the present invention, the retreat opening degree at which the intermittent collision between the valve body and the valve seat does not occur is an opening degree corresponding to the full closing of the exhaust gas recirculation control valve. It is characterized by being.

In this configuration, for example, as compared with the case where a value exceeding the collision opening range is adopted as the retreat opening,
When this retreat opening degree is realized, there is no fear that the recirculation amount of the exhaust gas becomes excessive.

According to a third aspect of the present invention, in the first or second aspect of the invention, the parameter used for calculating the collision opening area includes an intake air amount of the internal combustion engine or a physical amount correlated with the intake air amount. It is characterized by having.

The intake air amount of the internal combustion engine reflects, for example, the atmospheric pressure and the outside air temperature. In addition, it has been found that the amount of intake air of the internal combustion engine has a large effect on the presence or absence of vibration of the valve body and the vibration width. Therefore, grasping the intake air amount as the operating state of the internal combustion engine leads to calculation of a highly accurate (in other words, a narrow area) collision opening area in consideration of fluctuations in the atmospheric pressure, the outside air temperature, and the like. Therefore, the intermittent collision between the valve body and the valve seat based on the vibration of the valve body can be prevented, and the emission characteristics of the internal combustion engine can be improved at a higher level.

According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the exhaust gas recirculation control valve includes a spring member for urging the valve body in a direction to approach or separate from the valve seat. A valve drive unit that applies an urging force in a direction opposite to the urging force of the spring material to the valve body and that can change the urging force from the outside; the urging force from the spring material and the urging force from the valve driving unit Is characterized in that the valve body is positioned at a position where the valve body is balanced.

In this configuration, the valve element is positioned by a delicate balance of the urging forces opposing each other. Therefore, the valve body tends to vibrate, and when the valve body vibrates, the vibration width becomes large. As described above, the embodiment of the exhaust gas recirculation control device adopting the exhaust gas recirculation control valve, which is likely to cause a problem in configuration, is particularly effective for achieving the effect.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an exhaust gas recirculation control device for an internal combustion engine according to the present invention will be described below with reference to FIGS.

(Outline of Exhaust Gas Recirculation System for Internal Combustion Engine) FIG. 1 shows exhaust gas recirculation (so-called EGR = Exhaust Gas Recirculat).
FIG. 2 is a model diagram showing an internal combustion engine 101 including a control device. The internal combustion engine 101 is composed of a diesel engine. The internal combustion engine 101 has a fuel injection device 105. The supercharger 106 is connected to the intake passage 10 of the internal combustion engine 101.
2 and the exhaust passage 103, and performs a supercharging operation using the exhaust energy of the internal combustion engine 101. The intake throttle valve mechanism 107 is disposed in the intake passage 102 and controls the conduction state of the intake passage 102 in conjunction with the accelerator pedal 108. The intake throttle valve mechanism 107 allows a larger amount of air to flow through the intake passage 102 as the accelerator pedal 108 is depressed.

The exhaust gas recirculation control device comprises an internal combustion engine 101
An exhaust gas recirculation passage 11 provided between the intake passage 102 and the exhaust gas passage 103 of the vehicle, and an exhaust gas recirculation control valve 12 arranged in the middle of the exhaust gas recirculation passage 11 and capable of adjusting the opening of the passage 11
And a control system 13 for controlling the exhaust gas recirculation control valve 12.

Then, the exhaust gas recirculation control device
By recirculating a part of the exhaust gas flowing through the exhaust passage 103 of the internal combustion engine 101 to the intake passage 102 via the exhaust recirculation passage 11, the recirculated exhaust gas (inert gas)
Is sucked into the combustion chamber 104 of the internal combustion engine 101 together with fresh air. The introduction of the inert gas lowers the combustion temperature in the combustion chamber 104 and suppresses the generation of NOx due to this combustion.

However, when the combustion temperature in the combustion chamber 104 is excessively lowered, incomplete combustion occurs and CO (carbon monoxide) and HC (hydrocarbon) increase, and the internal combustion engine 1
01 also decreases. Therefore, the control system 13 controls the exhaust gas recirculation control valve 12 in accordance with the operation state of the internal combustion engine 101, thereby suitably adjusting the amount of exhaust gas recirculated to the intake passage 102. As a result, by providing the exhaust gas recirculation control device of the present embodiment, the internal combustion engine 101 can improve the emission characteristics without lowering the output.

Hereinafter, the exhaust gas recirculation control device will be described in detail. (Exhaust gas recirculation passage and exhaust gas recirculation control valve) As shown in FIG.
The exhaust pipe 21 connected to the intake pipe 03 and the intake pipe 22 connected to the intake passage 102 are connected by a joint pipe 23. The exhaust gas recirculation control valve 12 is disposed in the joint pipe 23 in the exhaust gas recirculation passage 11. That is, the joint pipe 2
3, an inflow passage 24 connected to the exhaust pipe 21;
An outlet passage 25 connected to the intake pipe 22;
A communication path 26 that communicates the communication paths 4 and 25 is formed. The inflow passage 24, the outflow passage 25, and the communication passage 26 constitute a part of the exhaust gas recirculation passage 11 in the joint pipe 23. The valve body 27 is arranged in the outflow passage 25 in the joint pipe 23, and the conduction state between the outflow passage 25 and the communication passage 26 can be changed. That is, the valve element 2 in the joint pipe 23
The periphery of the opening of the communication passage 26 opposed to 7 functions as a valve seat 28, and the communication passage 26 is a kind of valve hole.

A low-pressure actuator 29 is disposed outside the joint pipe 23. The low pressure actuator 29 includes a diaphragm 31 inside the housing 30.
Is provided. A diaphragm 31 is provided in the housing 30.
Thus, the atmospheric pressure chamber 32 in the lower part of the drawing and the control pressure chamber 3 in the upper part
3 are formed adjacent to each other in a cutoff state. The pressure in the control pressure chamber 33 is adjusted from the outside with the atmospheric pressure as an upper limit. In the low-pressure actuator 29, the diaphragm 31, the atmospheric pressure chamber 32, and the control pressure chamber 33 constitute a valve driving unit.

The control pressure chamber 33 accommodates an urging spring 34 composed of a coil spring as a spring material. The urging spring 34 extends the center of the diaphragm 31 downward in the drawing to increase the volume of the control pressure chamber 33. Energize. Diaphragm 31
Of the housing 30 and the joint pipe 2
3 is operatively connected via an operating rod 35 inserted therethrough. Therefore, the valve body 27 is interlocked with the vertical movement of the central portion of the diaphragm 31 via the operation rod 35. Valve 27
Is moved up and down in conjunction with the diaphragm 31, the shortest distance of the valve body 27 to the valve seat 28, that is, the lift amount of the valve body 27 also changes. When the lift amount of the valve body 27 changes, the opening degree of the communication passage 26, that is, the exhaust gas recirculation passage 11 also changes. The amount of exhaust gas recirculated from the exhaust passage 103 of the internal combustion engine 101 to the intake passage 102 depends on the opening degree of the communication passage 26 and the exhaust passage 103
And the pressure difference between the intake passage 102 and the intake passage 102.

In the exhaust gas recirculation control valve 12, the central part (the valve body 27) of the diaphragm 31 is provided with an urging force (from the valve drive unit) directed upward in the drawing based on the pressure difference between the control pressure chamber 33 and the atmospheric pressure chamber 32 acting on it. Is positioned at a position where the biasing force of the biasing spring 34 and the downwardly directed biasing force of the biasing spring 34 are balanced. This is because the influence of the pressure of the inflow passage 24 and the outflow passage 25 acting on the valve body 27 is ignored.

For example, when the pressure in the control pressure chamber 33 decreases and the urging force based on the pressure difference with the atmospheric pressure chamber 32 increases, the central portion of the diaphragm 31 moves upward so as to compensate for the increase. The urging force of the urging spring 34 is increased. Therefore, the lift amount of the valve body 27 increases, the opening degree of the communication passage 26 increases, and the recirculation amount of the exhaust gas also increases. Conversely, when the pressure in the control pressure chamber 33 rises and the urging force based on the pressure difference with the atmospheric pressure chamber 32 decreases, the central portion of the diaphragm 31 moves downward so as to compensate for this decrease, and the urging force is increased. The biasing force of the spring 34 is reduced. Therefore, the lift amount of the valve body 27 is reduced, the opening degree of the communication passage 26 is reduced, and the recirculation amount of the exhaust gas is also reduced.

When the atmospheric pressure chamber 32 and the control pressure chamber 33 are pressure-equalized, the urging force of the urging spring 34 directed downward in the drawing is dominant in positioning the valve body 27. Therefore, the valve body 27 is seated on the valve seat 28 and further downward movement is regulated,
The lift amount of the valve body 27 becomes “0” (the state shown in FIG. 1). When the lift amount of the valve body 27 is “0”, the opening degree of the communication passage 26 is fully closed, and the exhaust gas is not recirculated.

(Control System) As shown in FIG. 1, the low-pressure control valve 37 is disposed in a low-pressure source lower than the atmospheric pressure, such as the intake passage 102 of the internal combustion engine 101. Valve control passage 3
8 communicates the low pressure control valve 37 with the control pressure chamber 33 of the exhaust gas recirculation control valve 12. The low pressure control valve 37 is composed of a solenoid valve,
The operation is switched by an external electrical control between an on state where the low pressure source communicates with the valve control passage 38 and an off state where the atmospheric pressure region communicates with the valve control passage 38.
Therefore, when the low-pressure control valve 37 is turned on, a low pressure is guided to the control pressure chamber 33 of the exhaust gas recirculation control valve 12 via the valve control passage 38. Conversely, when the low-pressure control valve 37 is turned off, the control pressure chamber is turned off. Atmospheric pressure is led to 33.

The exhaust gas recirculation control device is provided with a control computer 41 for controlling the entire control. The control computer 41 normally controls the internal combustion engine 101 with respect to the fuel injection device 105 and the like.
In addition, an interruption process for the exhaust gas recirculation control device is periodically performed. Intake air amount sensor 42, internal combustion engine 101
The rotational speed sensor 43 for detecting the rotational speed Ne of the output shaft of the vehicle, the accelerator opening sensor 44 for detecting the amount of depression of the accelerator pedal 108 (hereinafter referred to as accelerator opening) Ac, the fuel injection device 105 and the low pressure Control valve 37
Are connected to the control computer 41, respectively.
The intake air amount sensor 42 is configured to detect the intake air amount Gn of the internal combustion engine 101 or a physical amount (for example, intake air pressure) correlated with the intake air amount Gn.

The control of the fuel injection device 105 by the control computer 41 is performed according to the following well-known procedure. The basic fuel injection amount is calculated based on the rotation speed Ne from the rotation speed sensor 43 and the accelerator opening Ac from the accelerator opening sensor 44. The rotation speed Ne from the rotation speed sensor 43 and the intake air amount Gn from the intake air amount sensor 42
The maximum fuel injection amount is calculated based on The basic fuel injection amount is compared with the maximum fuel injection amount.
v. Then, the fuel injection device 105 is operated to achieve the fuel injection amount Qv.

Further, the control computer 41 determines the intake air amount Gn from the intake air amount sensor 42, the rotation speed Ne from the rotation speed sensor 43, and the fuel injection device 105.
, An appropriate duty ratio is calculated based on the calculated fuel injection amount Qv, and a drive signal at this duty ratio is output to the low-pressure control valve 37. The low pressure control valve 37 is switched between an on state and an off state at a time ratio corresponding to a duty ratio of a drive signal provided from the control computer 41. Therefore, the control pressure chamber 3 of the exhaust gas recirculation control valve 12
Reference numeral 3 denotes a pressure corresponding to the duty ratio, and the lift amount of the valve body 27, that is, the opening degree of the communication passage 26 (the exhaust gas recirculation passage 11) is determined according to the pressure.

(Details of Control of Exhaust Gas Recirculation Control Valve by Control Computer) The control computer 41 controls the opening of the exhaust gas recirculation control valve 12 according to a procedure shown in a flowchart of FIG. 2 based on a program stored in advance. . The routine in FIG. 2 is a periodic interrupt routine that is started, for example, every several milliseconds.

That is, when controlling the opening degree of the exhaust gas recirculation control valve 12, first, at step S1, the rotational speed Ne as the operating state of the internal combustion engine 101 and another routine (fuel injection amount control of the internal combustion engine 101, not described in detail). The target opening degree of the exhaust gas recirculation control valve 12, that is, the target lift amount Lmap of the valve body 27 is calculated based on the fuel injection amount Qv calculated in the routine). This target lift amount Lmap is
It is calculated by referring to a map created in advance based on the relationship between the rotation speed Ne and the fuel injection amount Qv.

Here, in the exhaust gas recirculation control valve 12 having the above configuration, the valve body 27 may vibrate regardless of the control by the control computer 41. For example, if the cycle of the pressure pulsation of the exhaust gas coincides with the natural frequency of the valve body 27 and the pressure of the exhaust gas is so high that the valve body 27 is displaced, the valve body 27 resonates and vibrates. is there. This valve body 27
Is generated when the operation state of the internal combustion engine 101 enters a certain region, and furthermore, the vibration width is variously changed according to the operation state of the internal combustion engine 101. For example, the internal combustion engine 1
01 rotation speed Ne, fuel injection amount Qv and intake air amount G
It is known that n greatly affects the cycle of the pressure pulsation of the exhaust gas and the pressure of the exhaust gas, that is, the presence or absence of vibration of the valve body 27 and the vibration width.

Therefore, in step S2, the limited lift amount Llim is obtained from the rotational speed Ne, the fuel injection amount Qv, and the intake air amount Gn by using the calculation formula shown in the frame.
Is calculated. The limit lift amount Llim means that the valve body 27 may collide with the valve seat 28 due to vibration if the lift amount is less than the limit lift amount Llim. When the lift amount is “0”, the valve body 27 is seated on the valve seat 28, so that the internal combustion engine 101
Vibration does not occur in the valve body 27 irrespective of the operation state of. That is, in step S2, the limited lift amount Lli
Calculating m is essentially calculating a collision lift amount region (collision opening degree region) that exceeds “0” and is equal to or less than the limit lift amount Llim.

The coefficients "a", "b", "c", and "d" in the calculation formula of step S2 are the same as those of the internal combustion engine 1.
01 is calculated by a regression analysis from the limited lift amount Llim for each operating state obtained by an experiment in which various operating states are set. “E” is the internal combustion engine 101
Are correction values in consideration of the fact that the limit lift amount Llim varies depending on the configuration of the exhaust gas recirculation control valve 12 even in the same operation state.

In step S3, it is determined whether or not the target lift amount Lmap calculated in step S1 is "0", and the limit lift amount Ll calculated in step S2 is determined.
im is determined. In other words, in step S3, it is determined whether the target lift amount Lmap is outside the collision lift amount region.

If the determination in step S3 is YES, that is, with the target lift amount Lmap, the valve body 27 does not vibrate (when Lmap = 0), or even if the valve body 27 vibrates, the vibration width is small. If it is determined that the vehicle will not collide with the seat 28 (when Lmap> Llim), the target lift amount Lmap is maintained as it is. Therefore, the drive signal output to the low-pressure control valve 37 in step S4 is the target lift amount Lmap calculated in step S1.
In accordance with the duty ratio. As a result, the internal combustion engine 1
The recirculation amount of the exhaust gas from the exhaust passage 103 to the intake passage 102 in FIG. 01 is suitable for the operating state of the internal combustion engine 101.

On the other hand, if the determination in step S3 is NO, that is, the target lift amount Lm calculated in step S1.
When it is determined that the valve body 27 may collide with the valve seat 28 when the valve body 27 vibrates, the target lift amount Lmap is corrected to “0” as the retraction lift amount (retreat opening degree) in step S5. Is done. Therefore, in step S4, the drive signal for the low-pressure control valve 37 has a duty ratio corresponding to the target lift amount Lmap (= 0) corrected in step S5. As a result, in the exhaust gas recirculation control valve 12, the valve body 27 is seated on the valve seat 28, and the vibration of the valve body 27 is suppressed. Therefore, generation of abnormal noise and vibration due to intermittent collision between the valve body 27 and the valve seat 28 can be suppressed, and wear of the valve body 27 and the valve seat 28 can be prevented.

According to the above configuration, the following effects can be obtained. (1) In the present embodiment, even when the internal combustion engine 101 is in an operating state in which the valve body 27 of the exhaust gas recirculation control valve 12 generates vibration, the valve body 27 moves the retraction lift (= 0) is not forcibly displaced. In other words, even if the valve body 27 vibrates, if the vibration width is small enough not to interfere with the valve seat 28, from another viewpoint, the valve body 27 moves with respect to the valve seat 28 more than the vibration width of the valve body 27. If they are positioned separately, the exhaust gas recirculation passage 11 does not have the retreat opening degree. Therefore, the technology disclosed in Japanese Patent Application Laid-Open No. Hei 10-9064 (a configuration in which the exhaust gas recirculation passage 11 is completely closed in an operating state where the internal combustion engine 101 generates vibration in the valve body 27).
As compared with the case of adopting the above, it is possible to suppress the unnecessary stop of the recirculation of the exhaust gas to the intake passage 102. As a result, the valve body 27 and the valve seat 2 based on the vibration of the valve body 27
Intermittent collision with the internal combustion engine 10 and the internal combustion engine 10
1 can be improved at a high level.

(2) In the present embodiment, a fixed value “0” is adopted as the evacuation lift amount. Therefore, in comparison with the case where a value exceeding the limit lift amount Llim is adopted as the evacuation lift amount (described in another example later), when the evacuation lift amount is realized, the recirculation amount of the exhaust gas becomes excessive. There is no fear of becoming. Further, it is not necessary to take a procedure of changing the evacuation lift amount every time the limit lift amount Llim is calculated, and the program can be shortened, and the memory consumption of the control computer 41 can be reduced.

(3) In the present embodiment, in calculating the limit lift amount Llim, the operating state of the internal combustion engine 101 refers not only to the rotational speed Ne and the fuel injection amount Qv, but also to the intake air amount Gn. . The intake air amount Gn of the internal combustion engine 101 reflects, for example, the supercharging state of the supercharger 106, the atmospheric pressure, and the outside air temperature. Further, it is known that the intake air amount Gn of the internal combustion engine 101 has a large influence on the presence or absence of vibration of the valve body 27 and the vibration width.
Therefore, as the operating state of the internal combustion engine 101, the intake air amount G
In order to grasp n, it is necessary to take account of the occurrence of a response delay or the like in the supercharger 106 in the transient state of the internal combustion engine 101 and the fluctuation of the atmospheric pressure and the outside air temperature. Also, it leads to calculation of the limit lift amount Llim. Therefore, the valve body 27 based on the vibration of the valve body 27
Intermittent collision of the internal combustion engine 101 with the valve seat 28 and improvement of the emission characteristics of the internal combustion engine 101 can be achieved at a higher level.

In particular, a diesel engine (internal combustion engine 10
In 1), the intake air amount Gn is not always reflected in the fuel injection amount Qv (when the basic fuel injection amount is the fuel injection amount Qv). Therefore, ascertaining the intake air amount Gn in addition to the fuel injection amount Qv as the operating state of the diesel engine (internal combustion engine 101) is particularly effective in calculating the highly accurate limited lift amount Llim.

(4) In the present embodiment, the rotational speed Ne, the fuel injection amount Qv, and the intake air amount Gn of the internal combustion engine 101 used for calculating the limit lift amount Llim are:
All of these data are used when the fuel injection device 105 of the internal combustion engine 101 is controlled. Therefore, a special sensor only for calculating the limited lift amount Llim is not required, and the present invention can be applied to, for example, an existing exhaust gas recirculation control device only by adding logic. The existing exhaust gas recirculation control device is the same as the present embodiment in terms of hardware (FIG. 1), and is similar in software to step S1 in FIG.
The same configuration except that the exhaust gas recirculation control valve 12 is always controlled by the target lift amount Lmap calculated in the same manner as in the first embodiment.

(5) In this embodiment, the valve body 27 of the exhaust gas recirculation control valve 12 has an urging force based on a pressure difference between the control pressure chamber 33 and the atmospheric pressure chamber 32, and an urging spring opposing the urging force. Positioning is performed by a delicate balance with the urging force of. Therefore, vibration is easily generated in the valve body 27. Further, when vibration is generated in the valve body 27, the vibration width becomes large. It is particularly effective to embody the present invention in the exhaust gas recirculation control device employing the exhaust gas recirculation control valve 12 in which such a problem is likely to occur in terms of configuration.

The present invention can be practiced in the following modes without departing from the spirit of the present invention. A lift amount exceeding the limit lift amount Llim is set as a retreat lift amount (retreat opening degree). In this case, in order to prevent the recirculation amount of the exhaust gas from becoming excessive when the evacuation lift amount is realized, the evacuation lift amount is set to the target lift amount Lmap.
, That is, a value approaching the limit lift amount Llim. Therefore, the evacuation lift amount is equal to the limit lift amount Llim.
(For example, the evacuation lift amount = Llim + constant value).

In step S2 in FIG. 2, the limit lift amount Llim is calculated only from the rotational speed Ne of the internal combustion engine 101 and the intake air amount Gn. If the amount of data to be handled is reduced, the process of calculating the limited lift amount Llim in the control computer 41 also becomes faster.

In step S2 in FIG. 2, the limit lift amount Llim is calculated only from the rotational speed Ne of the internal combustion engine 101 and the fuel injection amount Qv. If the amount of data to be handled is reduced, the process of calculating the limited lift amount Llim in the control computer 41 also becomes faster.

In the exhaust gas recirculation control valve 12, the action direction of the urging force of the urging spring 34, the control pressure chamber 33 and the atmospheric pressure chamber 3
The direction of action of the urging force based on the pressure difference between the second embodiment and the second embodiment is opposite to that of the above embodiment. That is, the urging force of the urging spring 34 acts in a direction to separate the valve body 27 from the valve seat 28, and the urging force based on the pressure difference between the control pressure chamber 33 and the atmospheric pressure chamber 32 causes the valve body 27 to move. This is a configuration that acts in a direction to approach the valve seat 28.

As a valve drive unit of the exhaust gas recirculation control valve 12,
An electromagnetic configuration in which an urging force based on an electromagnetic attraction force is applied to the valve body 27. By doing so, the control computer 41 can directly electrically control the exhaust gas recirculation control valve 12. Therefore, the low-pressure control valve 37 and the valve control passage 38 can be omitted, and the configuration of the control system 13 can be simplified, and the control accuracy of the exhaust gas recirculation control valve 12 and the control accuracy of the exhaust gas recirculation amount can be improved.

As the actuator of the exhaust gas recirculation control valve 12, a structure comprising a step motor and a gear mechanism for converting the rotation of the step motor into linear movement of the valve body 27 is adopted. In this configuration, the valve body 27 is locked at the control position by the stop state holding capability peculiar to the step motor control. Therefore, even if vibration occurs in the valve body 27, the vibration width is as small as the amount of backlash existing in the gear mechanism, for example. From another point of view, there is still a possibility that vibration may occur in the valve body 27 although it is small compared to the above-described embodiment, and implementation in such a configuration deviates from the gist of the present invention. It does not do.

In the above embodiment, the control of the exhaust gas recirculation control valve 12 by the control computer 41 is open control. However, the present invention is not limited to this. A sensor for detecting the lift amount of the valve body 27 is provided, and the control computer 41 controls the exhaust gas recirculation so that the detected lift amount from this sensor becomes the target lift amount Lmap. The valve 12 may be configured to perform feedback control.

An internal combustion engine 10 composed of a gasoline engine
1 to be embodied in the exhaust gas recirculation control device. The technical idea that can be grasped from the above embodiment will be described.

(1) The exhaust gas recirculation control device for an internal combustion engine according to any one of claims 1 to 4, wherein the parameter used for calculating the collision opening degree range includes a rotation speed of the internal combustion engine. In this configuration, it is possible to calculate the collision opening degree region with high accuracy in consideration of the presence / absence of vibration of the valve body and the rotational speed that greatly affects the vibration width.

(2) The exhaust gas recirculation control device for an internal combustion engine according to any one of (1) to (4) and (1), wherein the parameter used for calculating the collision opening area includes a fuel injection amount of the internal combustion engine. .

In this configuration, it is possible to calculate the collision opening degree region with high accuracy in consideration of the presence / absence of vibration of the valve body and the amount of fuel injection which greatly affects the vibration width. (3) The internal combustion engine is composed of a diesel engine, and the parameters used for calculating the collision opening area include an intake air amount of the internal combustion engine or a physical amount correlated with the intake air amount and a fuel injection amount. Item 1. The exhaust gas recirculation control device for an internal combustion engine according to item 1 or (1).

In this configuration, the collision opening area can be calculated with high accuracy. (4) The exhaust gas recirculation control device for an internal combustion engine according to claim 3, wherein the internal combustion engine includes a supercharger that operates using the exhaust energy.

In this configuration, it is considered that a response delay or the like occurs in the supercharger in a transient state of the internal combustion engine.
Accurate calculation of the collision opening area can be performed.

[Brief description of the drawings]

FIG. 1 is a model diagram schematically showing the configuration of an embodiment of an exhaust gas recirculation control device according to the present invention.

FIG. 2 is a flowchart showing a control procedure.

[Explanation of symbols]

12 ... exhaust gas recirculation control valve, 27 ... valve element, 28 ... valve seat, 41
... A control computer for overall control, 101 an internal combustion engine, 102 an intake passage, 103 an exhaust passage.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuyoshi Ishizaka 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Co., Ltd. (72) Koji Hayashi 3-1-1 1-1 Hinodai, Hino City, Tokyo Hino Motors, Ltd. F term (reference) 3G062 AA05 EA04 EB15 EC02 FA09 GA01 GA04 GA06 GA15 GA21

Claims (4)

[Claims] 1. By bringing a valve body into and out of contact with a valve seat,
An exhaust gas recirculation control valve that controls the state of conduction between the exhaust passage and the intake passage of the internal combustion engine is provided, and the opening of the exhaust gas recirculation control valve is controlled to the target opening according to the operating state of the internal combustion engine. In an exhaust gas recirculation control device for an internal combustion engine that adjusts a recirculation amount of exhaust gas flowing through an exhaust passage to an intake passage, the valve body of the exhaust gas recirculation control valve is caused by vibration generated in a valve element of the exhaust gas recirculation control valve based on an operation state of the internal combustion engine. A collision opening area in which the valve seat intermittently collides is calculated, and when the target opening falls within the calculated collision opening area, the target opening is intermittently set between the valve body and the valve seat. An exhaust gas recirculation control device for an internal combustion engine, wherein the evacuation opening degree is corrected so as not to cause a serious collision. 2. The internal combustion engine according to claim 1, wherein the retreat opening degree at which the intermittent collision between the valve body and the valve seat does not occur is an opening degree corresponding to a full closing of the exhaust gas recirculation control valve. Exhaust gas recirculation control device. 3. The exhaust gas recirculation of an internal combustion engine according to claim 1, wherein the parameters used for calculating the collision opening degree range include an intake air amount of the internal combustion engine or a physical quantity correlated with the intake air amount. Control device. 4. An exhaust gas recirculation control valve comprising: a spring member for urging a valve body toward or away from a valve seat; and an urging force in a direction opposite to the urging force of the spring member. A valve drive unit that is operable and is capable of changing the biasing force from outside, wherein the valve body is positioned at a position where the biasing force from the spring material and the biasing force from the valve drive unit are balanced. Item 4. An exhaust gas recirculation control device for an internal combustion engine according to any one of Items 1 to 3.