JP2522756Y2 - Exhaust gas recirculation system - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to an exhaust gas recirculation system.
More specifically, the present invention relates to a structure of an exhaust gas recirculation device used in an intake / exhaust system equipped with an exhaust brake.

[0002]

As is well known, In the automotive engine, harmful components in the exhaust gas, in particular, the combustion temperature taken into the combustion chamber is taken out a portion of the exhaust gas in order to suppress the generation amount of the NO _X An exhaust gas recirculation device (hereinafter, referred to as an EGR device) is provided to suppress the exhaust gas recirculation.

FIG. 6 shows an example of an intake / exhaust system incorporating the above-described EGR device. In this case, a bypass C is provided between an exhaust path A and an intake path B, and the bypass C is provided in the bypass C. An on-off control valve D is arranged. The opening / closing control valve D described above has a concrete structure, as shown in FIG. 7, for setting the opening / closing amount of a housing 2 having an internal space partitioned by a diaphragm 1 and an exhaust port in a bypass C in the housing 2. And an EGR valve 3.

The above-mentioned housing 2 is provided with a diaphragm 1
A communication port 2A1 for the above-described EGR valve 3 for setting the pilot pressure of the EGR valve 3 is formed in one of the spaces 2A, and a main body of the EGR valve 3 is provided in an upper part of the one space. Has been fixed. Furthermore, one side of this space 2A
Is provided with a spring 4 for maintaining the diaphragm 1 in an equilibrium state in cooperation with the above-described negative pressure generating means.

On the other hand, the other space 2B partitioned by the diaphragm 1 is open to the atmosphere, and a lower portion thereof is provided with a passage 2C for communicating the exhaust side and the intake side of the bypass C. The valve body 3A of the EGR valve 3 faces the exhaust port 2C1. The above-mentioned EGR valve 3 sets the lift amount of the valve body 3A according to the engine operating state by a drive signal of a control unit (not shown) and controls the electromagnetic valve 18 to reach the set lift amount.
Engine operation by adjusting the pressure in the space 2A
A rod 3B extending from the one space 2A to the exhaust port 2C1 is provided, and an EGR amount corresponding to the state can be introduced to the intake side. The middle of the rod 3B is connected to the diaphragm 1 so as to be interlocked. In the opening / closing control valve D having such a structure, the pressure is set by the spring 4 located in one side 2A of the space and the negative pressure generating means.
The state where the valve body 3A closes the exhaust port 2C1 of the passage 2C via the diaphragm 1 is set to the normal state.
The open / close control valve D in the normal position is controlled by the engine
The EGR valve 3 is driven in accordance with the operation state to push the diaphragm 1 against the urging of the negative pressure generating means and the spring 4, so that the opening of the valve body 3A with respect to the exhaust port 2C1 is adjusted. It has become.

[0006]

[Problems to be Solved by the Invention] By the way, E
In the intake / exhaust system incorporating the GR device, for example,
When an exhaust brake is provided, there are the following problems.

That is, in FIG. 6, an on-off valve E arranged in the exhaust passage to constitute an operating portion of the exhaust brake is set to close the exhaust passage when the exhaust brake is operated. To reduce exhaust emissions,
When the discharge of the exhaust gas is suppressed, the pressure in the exhaust path increases, and as a result, a pressure is applied to push up the valve element 3A of the on-off control valve D of the EGR device, and the negative pressure is applied to the valve element 3A in the normal state. The spring is opened against the urging means and the spring 4. Therefore, when the valve body 3A is opened, the back pressure to the cylinder side increased by the on-off valve E as the exhaust brake does not act for the exhaust brake but acts for the recirculation in the EGR device. As a result, the effect of the exhaust brake is reduced.

Accordingly, an object of the present invention is to prevent the effect of the exhaust brake from being reduced in view of the above-described problem in the case where the EGR device is incorporated in the intake and exhaust system equipped with the exhaust brake. It is to obtain an exhaust gas recirculation device.

[0009]

In order to achieve this object, the present invention relates to an exhaust gas recirculation system used for an intake and exhaust system equipped with an exhaust brake. An on-off control valve disposed on the recirculation bypass provided, an exhaust port closed by a valve element of the on-off control valve, and an urging portion for imparting a habit of bringing the valve element into close contact with the exhaust port. And a sub-bypass provided between the sub-bypass,
When the pressure on the exhaust port reaches a predetermined value, the exhaust port
And a check valve for allowing the flow of the exhaust gas from the air to the urging portion.

The present invention also relates to an exhaust gas recirculation device used in an intake / exhaust system equipped with an exhaust brake, and an opening / closing control disposed in a recirculation bypass provided in the intake / exhaust system to constitute the exhaust gas recirculation device. A sub-bypass provided between the valve and an exhaust port closed by the valve element of the opening / closing control valve and an urging portion for imparting a habit of bringing the valve element into close contact with the exhaust port; A first solenoid valve provided in the sub-bypass for opening and closing the sub-bypass, and an air passage connected to a biasing portion of the opening / closing control valve for opening and closing this passage A second solenoid valve for connecting the solenoid valves to an output side, and a control unit connected to an input side to an exhaust brake switch and a pressure sensor for detecting a pressure in an exhaust path. The control unit controls the exhaust When the key switch is turned on, the second solenoid valve is set to the closed position, and when the pressure in the exhaust passage reaches a predetermined value or more in this state, the first solenoid valve is set to the open position. Then, exhaust gas is introduced from the exhaust port side toward the biasing portion.

Further, the present invention relates to an exhaust gas recirculation device used in an intake / exhaust system equipped with an exhaust brake, and an opening / closing control arranged in a recirculation bypass provided in the intake / exhaust system to constitute the exhaust gas recirculation device. A first electromagnetic valve disposed in an air passage connected between the valve and a biasing portion of the on-off control valve and a boost pressure generating portion of the turbocharger for opening and closing the passage; A second solenoid valve for opening and closing this passage, and a second solenoid valve for opening and closing this passage, and each of the solenoid valves connected to an output side, and an input side Has a control unit connected to an exhaust brake switch and a pressure sensor for detecting the pressure in the exhaust passage. The control unit operates the second solenoid valve when the exhaust brake switch is turned on. Set to the closed position,
In this state, when the pressure in the exhaust passage reaches a predetermined value or more, the first solenoid valve is set to the open position and the boost pressure of the turbocharger is applied to the urging portion. It is characterized in that.

[0012]

According to the present invention, when the exhaust brake is activated and the pressure in the exhaust passage reaches a predetermined value, the urging portion for the valve body of the on-off control valve disposed in the recirculation bypass is provided. Exhaust gas is introduced to the valve to increase the adhesion of the valve body to the exhaust port at the on-off valve.

Further, according to the present invention, the exhaust brake described above is provided.
When the key is operated and the pressure in the exhaust passage reaches a predetermined value or more, boost pressure from the turbocharger is applied to the urging portion, so that the valve body with respect to the exhaust side port. Is increased.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail with reference to FIGS.

FIG. 1 is a sectional view corresponding to FIG. 7 showing a structure of a main part of an exhaust gas recirculation device according to an embodiment of the present invention. That is, the opening / closing control valve 10 used in the exhaust gas recirculation device according to the present embodiment includes a housing 12 having a space partitioned by a diaphragm 11, as in the case shown in FIG.
An EGR valve 13 is provided, and one of the spaces 12A in the housing 12 is provided with a vacuum pump as negative pressure means.
(Not shown) and a communication port 12A1 to the solenoid valve 18
And a spring 14 for setting the diaphragm 11 in an equilibrium state together with the negative pressure generating means, so as to provide a fitting behavior of the valve body to the exhaust port described later. They are in the army.

The other side 12B of the space is open to the atmosphere, and a lower portion thereof is formed with a passage 12C for communicating the exhaust side and the intake side in the bypass C shown in FIG. exhaust side port of the - the door 12C1 is, EG
The valve body 13A of the R valve 13 is opposed. The above-described EGR valve 13 is set to a lift amount according to the engine operating state , for example, by a drive signal of a control unit (not shown).
A rod 13B extending from the one space 12A to the exhaust port 2C1 can introduce an EGR amount corresponding to the engine operating state to the intake side. And the rod 13B
Is connected to the diaphragm 1 so as to be interlocked. On the other hand, one of the above-mentioned spaces forming the urging portion 1
2A and the exhaust port 12C1, there is a sub-bypass 1
The sub-bypass 15 is provided with a check valve 16. The above-described check valve 16 has a habit of allowing the flow of exhaust gas from the exhaust port 12C1 toward one side 12A of the urging portion when the pressure in the exhaust passage reaches a predetermined value. In this case, the predetermined pressure acts on the valve body 13A to lift the valve body 13A away from the exhaust port and 12C1 because the state of equilibrium by the negative pressure means and the spring 14 at the urging portion is broken. When trying to pressure it.

Since the present embodiment has the above structure,
Now, when the exhaust brake is not operated, the pressure in the exhaust passage against the valve body 13A which is in close contact with the exhaust side port 12C1 does not increase, so that the diaphragm 11 is in an equilibrium state. The lift amount of the valve body 13A of the EGR valve 13 is controlled in accordance with the engine operating state , and the normal EGR control is executed.

On the other hand, when the exhaust brake is activated, the on-off valve in the exhaust path is set to be closed,
When the pressure in the exhaust passage reaches the above-described predetermined pressure value, the check valve 16 is opened, and the urging portion is moved from the exhaust port 12C1.
The exhaust gas flows toward (for convenience, reference numeral 12A). Accordingly, in the urging portion 12A, the pressure on the diaphragm 11 increases by the amount of the exhaust pressure taken in from the exhaust port 12C1, and as a result, the diaphragm 1
The valve body 13A is strengthened in close contact with the exhaust port 12C1 via the rod 13B connected to the exhaust port 1, and the exhaust gas is prevented from being recirculated to the EGR device side in the exhaust path. The result is that the working pressure of the exhaust air is not reduced.

By the way, in this embodiment, it is also possible to surely suppress a decrease in the pressure acting on the on-off valve in the exhaust passage during the exhaust brake operation.

FIG. 2 shows the above-mentioned case. In this case, a first solenoid valve for opening and closing the sub-bypass 15 is used instead of the check valve 16 provided in the sub-bypass 15. 17 as the second solenoid valve, and
A magnetic valve 18 is provided. And the second solenoid valve 18
It is connected to a vacuum pump 22, and drives controlled by a control part 19 of the respective solenoid valves 17, 18. That is, the control unit 19 controls the exhaust
A key operation switch 20 and a pressure sensor 21 for detecting the pressure in the exhaust passage are connected, and the above-mentioned solenoid valves 17 and 18 are connected to the output side via a drive unit (not shown). In the control unit 19, the second solenoid valve 18 is closed when the exhaust brake operation switch 20 is turned on, and the pressure (P) in the exhaust path becomes a predetermined value as shown in FIG. When the value is equal to or more than the value (P ₀ ), the first solenoid valve 1
7 is opened. That is, the second solenoid valve
By closing the valve 18 , the valve body 13A is connected to the exhaust port 12C.
The action of the negative pressure generating means for giving the habit of setting the lift away from the port is released, and the exhaust pressure from the exhaust port 12C1 promotes the close contact of the valve body 13A with the exhaust port 12C1. It is made to let.

Therefore, in this structure, the valve body 13 for the exhaust port 12C1 is different from the structure shown in FIG.
It is possible to further increase the contact force of A, and to minimize the decrease in the exhaust pressure on the on-off valve of the exhaust brake to improve the effectiveness of the exhaust brake.

By the way, in the structure shown in FIG. 1 and FIG. 2, the exhaust port 12C1 with respect to the urging portion 12A.
In this case, the displacement of the diaphragm 11 is promoted by taking in the exhaust air from the airbag, but in this case, the inside of the urging portion 12A may be contaminated by the exhaust air.

Therefore, in this embodiment, it is also possible to adopt a structure for preventing the above-mentioned biasing portion from being contaminated.

That is, FIG. 4 shows a structure in the above-described case. In this structure, a passage 23 connected to the turbocharger 22 is connected to the urging portion 12A instead of the sub-bypass 15. The first solenoid valve is provided in the passage 23.

In this structure, in the flowchart of FIG. 5 for explaining the operation of the control section, it is determined whether or not the exhaust brake operation switch 20 (referred to as an exhaust for convenience in the drawing) is turned on. When the switch is turned on, the pilot pressure at the time of performing the lift control of the valve body 13A by the EGR valve 13 by closing the second electromagnetic valve 18 is eliminated, and the pressure in the exhaust passage by the pressure sensor 21 is reduced. When the predetermined value is reached, the first solenoid valve 17 is opened and the
The boost pressure from the jar 22 is applied to the urging portion 12A,
The pressure of the exhaust path maintains its state position until the predetermined value or less, if it becomes less than the predetermined value, the first solenoid valve 1
7 closed state position and controls the second solenoid valve 18 to perform the normal EGR control.

According to such a structure, the air introduced into the urging section 12A is the same fresh air as the intake air, so that the inside of the urging section 12A is not contaminated by, for example, soot.

[0027]

As described above, according to the present invention, when the exhaust brake is activated, the exhaust gas is taken in the on-off control valve in the bypass located between the exhaust path and the intake path on the EGR device side. The close contact of the valve body with the side opening can be enhanced. Therefore, during the operation of the exhaust brake, it is possible to prevent the pressure in the exhaust passage from rising and the exhaust gas from flowing into the EGR device, thereby reducing the effect of the exhaust brake. It can be avoided beforehand.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a main structure of an exhaust gas recirculation device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view corresponding to FIG. 1 for explaining a partially modified example of the main part structure shown in FIG. 1;

FIG. 3 is a diagram for explaining operation characteristics of the structure shown in FIG. 2;

FIG. 4 is a sectional view corresponding to FIG. 2 for explaining another modification of the main part of the structure shown in FIG. 2;

FIG. 5 is a flowchart for explaining the operation according to the modification shown in FIG. 4;

FIG. 6 is a model diagram for explaining a configuration of a conventional exhaust gas recirculation device.

FIG. 7 is a cross-sectional view corresponding to FIG. 1 for explaining a main part of the exhaust gas recirculation device shown in FIG. 6;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Opening-and-closing control valve 11 Diaphragm 12 Housing 12A One of the spaces partitioned by a diaphragm and forming an urging portion 12A1 A communication port to a negative pressure generating means 12B The other of a space partitioned by a diaphragm 12C A passage connecting the exhaust side and the intake side. 12C1 Exhaust port 13 EGR valve 13A Valve body 13B Rod 15 Sub-bypass 16 Check valve 17 First solenoid valve 18 Second solenoid valve 19 Control unit 20 Exhaust brake operation switch 21 Pressure sensor in exhaust path 22 Turbocharger

Claims (3)

(57) [Scope of request for utility model registration] 1. An exhaust gas recirculation device used in an intake / exhaust system equipped with an exhaust brake, comprising: an open / close control valve arranged in a recirculation bypass provided in the intake / exhaust system to constitute the exhaust gas recirculation device. A sub-bypass provided between an exhaust port closed by a valve element of the on-off control valve and an urging portion for imparting a habit of bringing the valve element into close contact with the exhaust port; A check valve that is arranged inside the exhaust port and allows the flow of exhaust gas from the exhaust port toward the urging portion when the pressure of the exhaust port reaches a predetermined value. An exhaust gas recirculation device characterized by the above-mentioned. 2. An exhaust gas recirculation device used in an intake / exhaust system equipped with an exhaust brake, comprising: an open / close control valve disposed on a recirculation bypass provided in the intake / exhaust system to constitute the exhaust gas recirculation device. A sub-bypass provided between an exhaust port closed by a valve element of the on-off control valve and an urging portion for imparting a habit of bringing the valve element into close contact with the exhaust port; A first solenoid valve for opening and closing the sub-bypass, an air passage connected to a biasing portion of the on-off control valve, and a first solenoid valve for opening and closing the passage. An electromagnetic valve connected to an output side, and a control unit connected to an input side to an exhaust brake switch and a pressure sensor for detecting pressure in an exhaust path. Is the exhaust brake switch. Is turned on, the second solenoid valve is set to a closed position, and in this state, when the pressure in the exhaust passage reaches a predetermined value or more, the first solenoid valve is set to an open position. An exhaust gas recirculation device, wherein exhaust gas is introduced from the exhaust port side toward the biasing portion. 3. An exhaust gas recirculation device used in an intake / exhaust system equipped with an exhaust brake, comprising: an open / close control valve arranged on a recirculation bypass provided in the intake / exhaust system to constitute the exhaust gas recirculation device. A first solenoid valve disposed in an air passage connected between the urging portion of the opening / closing control valve and the boost pressure generating portion of the turbocharger to open and close the passage; A second solenoid valve for opening and closing the passage, which is provided in an air passage connected to the urging portion of the on-off control valve; A control unit connected to a brake switch and a pressure sensor for detecting a pressure in the exhaust passage, wherein the control unit closes the second electromagnetic valve when the exhaust brake switch is turned on. And in this state the pressure in the exhaust The exhaust gas recirculation is characterized in that the first solenoid valve is set to the open position when the pressure exceeds the value, and the boost pressure of the turbocharger is applied toward the urging portion. apparatus.