JP3888518B2 - Exhaust purification device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust emission control device for purifying exhaust gas discharged from an internal combustion engine (hereinafter, the internal combustion engine is referred to as an “engine”).
[0002]
[Prior art]
For example, as disclosed in JP-A-6-26328, JP-A-2001-65333 and JP-A-10-212931, nitrogen oxides contained in exhaust gas exhausted from an engine such as a diesel engine ( In order to remove (NOx), an exhaust purification system in which a reducing agent is added and introduced to the inlet side of a NOx catalyst installed in the exhaust system of the engine is known. As the reducing agent, a hydrocarbon-based reducing agent is used. In the case of a diesel engine, light oil as a fuel can be used as the reducing agent. An exhaust gas purification system installed in an engine exhaust system includes the above-described NOx catalyst and an exhaust gas purification device that is installed upstream of the NOx catalyst and introduces fuel as a reducing agent.
2. Description of the Related Art Conventionally, an exhaust emission control device includes an electromagnetic valve that is driven in response to supplied electric power, a fuel pipe that is supplied with fuel, a nozzle portion that is injected with fuel, and the like.
[0003]
[Problems to be solved by the invention]
However, in the case of a conventional exhaust purification system, the solenoid valve, fuel piping, and nozzle portion of the exhaust purification device have different configurations and forms for each applied engine or exhaust purification system, and the exhaust purification device itself is configured. It has not been. Therefore, there is an advantage that the configuration and form of the exhaust purification device can be optimized in accordance with the engine to which the exhaust purification device is applied, while the design and setting of the exhaust purification device is required for each applied engine.
As a result, there is a problem that the product cannot be standardized as an exhaust purification device of the exhaust purification system, and the cost of the exhaust purification device and thus the exhaust purification system is increased.
[0004]
SUMMARY OF THE INVENTION An object of the present invention is to provide an exhaust emission control device that can be easily standardized and set according to the engine to be applied.
[0005]
[Means for Solving the Problems]
According to the exhaust emission control device of the first aspect of the present invention, the functional part having the on-off valve and the solenoid and the holding mounting part for mounting the functional part on the exhaust system of the engine are configured separately. Therefore, it can be set as the structure and form which standardized the function part, and only the structure and form of a holding | maintenance mounting part can be changed according to the engine applied. Therefore, the setting according to the engine to which it is applied can be easily performed.
[0006]
According to the exhaust emission control device of the second aspect of the present invention, the holding and mounting portion has the holding means, the introducing portion, the delivery port, and the mounting means that are not included in the functional portion. For this reason, the functional unit is composed of an on-off valve and a driving means, and standardization of the functional unit can be easily performed.
According to the exhaust emission control device of the third aspect of the present invention, the holding and mounting portion is composed of a plurality of accommodating members capable of accommodating the functional portion. By dividing the holding and mounting portion into a plurality of receiving members, the functional portion can be easily stored in the holding and mounting portion.
[0007]
According to the exhaust emission control device of the fourth aspect of the present invention, the plurality of housing members are combined to form a holding mounting portion. That is, after accommodating a functional part in a holding | maintenance mounting part, a some accommodating member is couple | bonded. Therefore, it is easy to handle the holding mounting portion and the functional portion.
According to the exhaust emission control device of the fifth aspect of the present invention, the functional part is coupled to one of the plurality of accommodating members divided. Therefore, the holding and mounting portion and the functional portion are integrally formed, and the holding and mounting portion and the functional portion are easy to handle.
[0008]
According to the exhaust emission control device of the sixth aspect of the present invention, the plurality of housing members and the functional portion and the housing member are coupled by welding or mechanically coupled by, for example, screws. Therefore, the holding function unit and the function unit can be configured to be a strong integrated structure.
According to the exhaust emission control device of the seventh aspect of the present invention, the functional portion and the holding mounting portion are sealed in a liquid-tight manner. Therefore, leakage of the reducing agent can be prevented.
[0009]
According to the exhaust emission control device of the eighth aspect of the present invention, the nozzle portion is formed separately from the functional portion. Therefore, the configuration and form of the nozzle portion can be changed according to the applied engine. Therefore, it is possible to easily carry out setting according to the applied engine.
According to the exhaust emission control device of the ninth aspect of the present invention, the nozzle hole formed in the nozzle portion is formed on the downstream side of the flow of exhaust gas in the intake system. Foreign matter such as fine particles contained in the exhaust is conveyed along the flow of the exhaust. Therefore, by forming the nozzle hole on the downstream side, it is possible to prevent the nozzle hole from being clogged with foreign matter contained in the exhaust gas.
[0010]
According to the exhaust emission control device of the tenth or eleventh aspect of the present invention, the nozzle portion is coupled to the holding mounting portion or the functional portion. For this reason, the nozzle portion is integrated with the holding and mounting portion or the functional portion, and the nozzle portion is easy to handle.
According to the exhaust emission control device of the twelfth aspect of the present invention, the nozzle portion and the functional portion or the holding mounting portion are coupled by welding or mechanically coupled by, for example, screws. Therefore, the nozzle part and the functional part or the holding / mounting part can be formed into a strong integrated structure.
According to the exhaust emission control device of the thirteenth aspect of the present invention, the gap between the nozzle portion and the functional portion is liquid-tightly sealed. Therefore, leakage of the reducing agent can be prevented.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example showing an embodiment of the present invention will be described with reference to the drawings.
FIG. 2 shows an exhaust gas purification system for a diesel engine to which an exhaust gas purification apparatus according to an embodiment of the present invention is applied. In this embodiment, an example in which the exhaust emission control device of the present invention is applied to a 4-cylinder diesel engine will be described.
As shown in FIG. 2, the exhaust purification system 1 mainly includes an exhaust purification device 10, a NOx catalyst 2, and a reducing agent supply device 3.
[0012]
The exhaust purification device 10 is mounted on an exhaust pipe 6 that constitutes an exhaust system of the diesel engine 5, and injects a reducing agent into the exhaust flowing through the exhaust pipe 6. The exhaust purification device 10 is installed on the NOx catalyst 2 inlet side of the exhaust pipe 6. In the case of a diesel engine equipped with a supercharger (not shown), the exhaust purification device 10 may be installed on either the inlet side or the outlet side of the supercharger installed in the middle of the exhaust pipe 6.
[0013]
The exhaust system includes the aforementioned exhaust pipe 6 and an exhaust manifold 61 that branches from the exhaust pipe 6 to each cylinder 51 of the diesel engine 5. In the exhaust pipe 6, the exhaust purification device 10 and the NOx catalyst 2 are sequentially installed in the exhaust flow direction.
[0014]
The exhaust emission control device 10 intermittently injects the reducing agent according to a command from the ECU 7. Various types of information such as the intake air flow rate, the intake pressure, the rotational speed of the diesel engine 5 and the accelerator opening are input to the ECU 7 from various sensors installed in the diesel engine 5. The ECU 7 controls the injection amount of fuel injected into each cylinder 51 of the diesel engine 5 from the input information and also controls the exhaust purification device 10. The ECU 7 calculates the NOx emission amount that correlates with the rotational speed of the diesel engine 5, the accelerator opening, and the like. Based on the calculated NOx emission amount, the ECU 7 determines the injection amount and the injection timing of the reducing agent injected from the exhaust purification device 10. Set. Then, the ECU 7 controls the exhaust purification device 10 based on the set injection amount and timing of the reducing agent.
For the NOx catalyst 2, for example, a catalyst in which a noble metal-based active component such as Pt or Pd is supported on a carrier such as ceramic or metal oxide is used. The NOx catalyst 2 is formed into, for example, a monolith type or a pellet type.
[0015]
The reducing agent supply device 3 includes a reducing agent tank and a feed pump (not shown), and a feed pipe 8. The reducing agent supply device 3 supplies the reducing agent stored in the reducing agent tank to the exhaust gas purification device 10. The reducing agent stored in the reducing agent tank is supplied to the exhaust gas purification device 10 via the feeding pipe 8 by the feeding pump. As the reducing agent, a hydrocarbon-based reducing agent is used, and in the case of the present embodiment, light oil that is a fuel of the diesel engine 5 is used as the reducing agent.
[0016]
Next, the exhaust emission control device 10 will be described in detail.
As shown in FIGS. 1 and 3, the exhaust emission control device 10 according to this embodiment includes a functional unit 20, a holding / mounting unit 70, and a nozzle unit 80.
The functional unit 20 includes an on-off valve 30 that intermittently injects the reducing agent from the nozzle unit 80, and a driving unit 40 that drives the on-off valve 30. The functional unit 20 includes a cylindrical member 21, and a fluid passage 22 is formed inside the cylindrical member 21.
[0017]
The on-off valve 30 has a valve member 31 and a valve body 32. A contact portion 33 is formed on the outer periphery of the valve member 31, and the contact portion 33 can contact a valve seat portion 34 formed on the inner periphery of the valve body 32. The flow of the reducing agent is released when the contact portion 33 is separated from the valve seat portion 34, and the flow of the reducing agent is blocked when the contact portion 33 is seated on the valve seat portion 34.
[0018]
The driving means 40 includes a coil 41, a stator 42, a stator housing 43 and a core 44. The coil 41 is accommodated in the stator 42 and the stator housing 43, and generates a magnetic field when energized. A terminal portion 45 is connected to the coil 41, and an end portion of the terminal portion 45 on the side opposite to the coil is installed on the connector 23. The terminal portion 45 is electrically connected to the ECU 7, and power is supplied from the ECU 7 to the coil 41.
[0019]
The stator 42 and the stator housing 43 are made of a magnetic material, and form a magnetic circuit with the core 44 by a magnetic field generated in the coil 41. The stator 42 and the stator housing 43 are joined together by welding, for example. The stator housing 43 is formed with a valve chamber 46 on the inner peripheral side, and a valve member 31 of the on-off valve 30 is accommodated in the valve chamber 46 so as to be capable of reciprocating in the axial direction. The valve body 32 is coupled to the end of the stator housing 43 by welding, for example. The core 44 is integrally coupled to the valve member 31 at the end of the on-off valve 30 on the side opposite to the valve member 31. A fluid passage 441 through which the reducing agent flows is formed in the core 44.
[0020]
When electric power is supplied from the ECU 7 to the coil 41, a magnetic field is generated in the coil 41, and a magnetic circuit is formed in the stator 42, the stator housing 43 and the core 44 installed around the coil 41. Thereby, a magnetic attractive force is generated between the stator 42 and the core 44, and the core 44 is attracted toward the stator 42. Therefore, the valve member 31 moves upward in FIG. 1, and the contact portion 33 is separated from the valve seat portion 34. A stopper 24 is installed between the stator housing 43 and the valve body 32, and the upward movement of the valve member 31 in FIG. 1 is restricted.
[0021]
The stator 42 is provided with a coil 41 on the outer peripheral portion, and an accommodating chamber 48 for accommodating a spring 47 of a driving means is formed on the inner peripheral portion. One end of the spring 47 is in contact with the stator 42, and the other end is in contact with the core 44 integral with the valve member 31, and the contact portion 33 seats the valve member 31 on the valve seat portion 34. Energizing in the direction. Therefore, when the supply of power to the coil 41 is stopped, the magnetic attractive force between the stator 42 and the core 44 disappears, and the urging force of the spring 47 moves the valve member 31 downward in FIG. The contact portion 33 is seated on the valve seat portion 34.
[0022]
The cylinder member 21 has a fluid passage 22 formed therein. One end of the cylindrical member 21 is coupled to the stator 42 by welding, for example.
The stator 42, the stator housing 43, the cylindrical member 20, and the connector 23 are covered with a resin mold 25.
[0023]
The holding and mounting portion 70 includes a housing connector 71 and a housing body 72 that are formed as separate members. The housing connector 71 and the housing body 72 as holding means are formed in a cylindrical shape, and the functional unit 20 is accommodated and held therein. The housing connector 71 is formed with a clamp base 73 as mounting means for fixing the exhaust purification device 10 to the exhaust pipe 6. The housing connector 71 and the housing body 72 are joined together by welding, for example. The housing body 72 and the stator housing 43 of the functional unit 20 are joined together by welding, for example.
[0024]
The housing connector 71 is provided with an introduction portion 74 into which fuel is introduced. The introduction unit 74 is connected to the feeding pipe 8, and the reducing agent is supplied from the reducing agent supply device 3 through the feeding pipe 8. An end portion of the introduction portion 74 of the housing connector 71 serves as a delivery port 75, and the reducing agent introduced from the introduction portion 74 is delivered from the delivery port 75 to the fluid passage 22 of the functional unit 20. An O-ring 26 that is a seal member is installed between the inner peripheral portion of the housing connector 71 and the outer peripheral portion of the cylindrical member 20. The O-ring 26 provides a liquid-tight seal between the housing connector 71 and the cylindrical member 20, and prevents the reducing agent delivered from the delivery port 75 from leaking between the functional unit 20 and the holding mounting unit 70. . Further, an O-ring 27 is also provided between the outer peripheral side of the stator housing 43 and the inner peripheral side of the housing body 72 to seal the space between the stator housing 43 and the housing body 72 in a liquid-tight manner. Prevents leakage.
[0025]
The nozzle portion 80 has a nozzle body 81, and the nozzle body 81 is installed at the end of the housing body 72. The nozzle body 81 is coupled to the housing body 72 by screwing with the retaining nut 11. A gasket 28 is installed between the housing body 72 and the nozzle body 81 to seal the space between the housing body 72 and the nozzle body 81 and prevent leakage of the reducing agent together with the O-ring 27. Yes.
[0026]
The nozzle body 81 has a nozzle sack 82 and a nozzle hole 83 formed therein. The nozzle sack 82 is formed along the axial direction of the nozzle body 81, and feeds the reducing agent sent out by opening the on-off valve 30 to the nozzle hole 83. The nozzle hole 83 has one end opened to the nozzle sack 82 and the other end opened to the outer peripheral side of the nozzle body 81. The nozzle hole 83 is formed at a predetermined angle with respect to the axis of the nozzle body 81. The opening on the outer peripheral side of the nozzle body 81 of the nozzle hole 83 is located in the downstream direction of the exhaust gas flowing through the exhaust pipe 6, that is, on the NOx catalyst 2 side.
[0027]
As shown in FIG. 4, the exhaust purification device 10 is fixed to the attachment portion 62 of the exhaust pipe 6 by fitting a clamp 90 to a clamp base 73 of the housing connector 71. As shown in FIG. 3, since the functional unit 20 and the holding and mounting unit 70 are configured separately, the functional unit 20 is held without changing the shape of the functional unit 20 according to the form of the installed diesel engine 5. Only the shape of the mounting portion 70 can be changed.
[0028]
Next, the operation of the exhaust emission control device 10 according to one embodiment of the present invention will be described.
Exhaust gas discharged from each cylinder 51 of the diesel engine 5 is collected by the exhaust manifold 61 into the exhaust pipe 6. The exhaust collected in the exhaust pipe 6 flows in the direction of the NOx catalyst 2 in the exhaust pipe 6.
[0029]
In the ECU 7, the NOx emission amount contained in the exhaust gas is calculated from the rotational speed of the diesel engine 5 and the accelerator opening, and the injection amount and injection timing of the reducing agent injected from the exhaust purification device 10 are set. Then, the ECU 7 applies a pulse current to the coil 41 based on the set reducing agent injection amount and injection timing. When a current is applied to the coil 41, a magnetic field is generated in the coil 41. A magnetic circuit is formed in the stator 42, the stator housing 43 and the core 44 by the generated magnetic field, and the core 44 is attracted to the stator 42.
[0030]
When the core 44 is attracted by the stator 42, the valve member 31 formed integrally with the core 44 moves upward in FIG. 1 against the urging force of the spring 47, and from the valve seat portion 34 to the contact portion 33. Sits away. The reducing agent introduced into the exhaust purification device 10 from the introduction part 74 flows into the fluid passage 22 of the cylindrical member 21 from the delivery port 75 and is formed in the through hole 421 formed in the stator 42, the accommodation chamber 48, and the core 44. It is supplied to the inlet side of the nozzle portion 80 via the fluid passage 441 formed in the stator housing 43, the valve chamber 46 formed in the stator housing 43, and the fluid passage 241 formed in the stopper 24. When the abutting portion 33 is separated from the valve seat portion 34, the reducing agent passes between the valve seat portion 34 and the abutting portion 33, and passes through the nozzle sac 82 of the nozzle portion 80 from the nozzle hole 83. It is injected into the exhaust pipe 6.
[0031]
Exhaust gas discharged from each cylinder 51 of the diesel engine 5 flows in the exhaust pipe 6 in the direction of arrow A shown in FIG. 4, and the reducing agent injected from the exhaust gas purification device 10 is mixed with the exhaust gas. The exhaust gas mixed with the reducing agent is fed to the NOx catalyst 2, and the NOx contained in the exhaust gas is reduced by the NOx catalyst 2. Exhaust gas that has passed through the NOx catalyst 2 is released into the atmosphere.
[0032]
When a predetermined amount of reducing agent is injected from the exhaust purification device 10 at a predetermined time, the ECU 7 stops applying current to the coil 41. Therefore, the magnetic attractive force between the stator 42 and the core 44 disappears, and the valve member 31 integrated with the core 44 moves downward in FIG. 1 by the urging force of the spring 47. Then, when the contact portion 33 is seated on the valve seat portion 34, the injection of the reducing agent is terminated.
[0033]
As described above, according to the exhaust emission control device 10 according to the embodiment of the present invention described above, the functional unit 20 including the opening / closing valve 30 and the driving means 40 for driving the opening / closing valve 30 includes the housing connector 71 and the housing body 72 of the holding mounting unit 70. , And the nozzle unit 80 are configured separately. As a result, only by changing the form of the housing connector 71 or the housing body 72 of the holding and mounting part 70, the exhaust purification apparatus 10 is mounted according to the configuration and form of the engine to which the functional part 20 is applied without changing the shape of the functional part 20. be able to. For example, the position where the exhaust purification device 10 is mounted on the exhaust pipe 6, the size of the exhaust pipe 6, the shape of the portion where the nozzle portion 80 protrudes to the exhaust pipe 6, and the size, shape, or formation angle of the injection hole 83 And the like can be easily set without changing the specifications of the functional unit 20. Therefore, the exhaust emission control device 10 can standardize the specifications of the functional unit 20 regardless of the engine to which it is applied. Further, by standardizing the specifications of the functional unit 20, the versatility of the members constituting the functional unit 20 can be improved, and the cost of the exhaust emission control device 10 can be reduced.
[0034]
In addition, according to the exhaust gas purification apparatus 10 according to one embodiment of the present invention, the nozzle hole 83 formed in the nozzle portion 80 is formed to open in the downstream direction of the exhaust gas flow, that is, on the NOx catalyst 2 side. Therefore, foreign matter such as fine particles contained in the exhaust does not adhere to the periphery of the nozzle hole 83, and the nozzle hole 83 can be prevented from being clogged.
[0035]
As described above, in the embodiment of the present invention described above, the stator housing of the functional part and the housing body of the holding mounting part, and the connector housing and the housing body are joined by welding, and the housing body of the holding mounting part and the nozzle body of the nozzle part An example in which the screw is coupled with a retaining nut has been described. However, in the present invention, it is possible to change the portion connected by welding to a screw connection or other mechanical connection, and it is also possible to change the portion connected to the screw to welding or other mechanical connection. is there. Further, although the liquid tightness in each part of the exhaust purification device is secured by the O-ring and the gasket, the liquid tightness may be secured by other means and is not limited to the O-ring or the gasket.
[0036]
Furthermore, in the embodiment of the present invention, the case where the functional part, the holding / mounting part, and the nozzle part are configured separately has been described. However, the nozzle part may be integrated with the functional part or the holding / mounting part. Moreover, it is also possible to configure the functional part and the holding / mounting part integrally with only the nozzle part as a separate body.
Furthermore, in the embodiment of the present invention, the example in which the exhaust purification device is applied to a diesel engine has been described. However, the present invention can be applied not only to a diesel engine but also to an engine such as a gasoline engine.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an exhaust emission control device according to an embodiment of the present invention.
FIG. 2 is a schematic diagram showing an exhaust purification system to which an exhaust purification apparatus according to an embodiment of the present invention is applied.
FIG. 3 is a schematic cross-sectional view showing a state where an exhaust emission control device according to an embodiment of the present invention is separated into a functional part, a holding / mounting part, and a nozzle part.
FIG. 4 is a schematic cross-sectional view showing a mounting portion where an exhaust emission control device according to an embodiment of the present invention is mounted on an exhaust pipe.
[Explanation of symbols]
5 Diesel engine (internal combustion engine)
6 Exhaust pipe (exhaust system)
DESCRIPTION OF SYMBOLS 10 Exhaust gas purification apparatus 20 Function part 30 On-off valve 31 Valve member 32 Valve body 40 Driving means 70 Holding mounting part 71 Housing connector (holding means, accommodating member)
72 Housing body (holding means, receiving member)
73 Clamp base (mounting means)
74 Introduction part 75 Delivery port 80 Nozzle part 83 Injection hole

Claims (13)

An exhaust purification device mounted on an exhaust system of an internal combustion engine,
An introduction part into which the reducing agent is introduced;
A nozzle part from which the reducing agent introduced from the introduction part is injected;
An on-off valve for intermittently injecting the reducing agent from the nozzle part, and a functional part having a driving means for driving the on-off valve;
A holding and mounting portion that is formed separately from the functional portion and for mounting the functional portion on the exhaust system ;
The on-off valve has a valve member capable of reciprocating in the axial direction, and a valve body on which the valve member is seated or separated,
The nozzle portion has a nozzle body that is formed separately from the valve body on the downstream side of the valve body in the flow direction of the reducing agent and is provided with an injection hole for injecting the reducing agent.
The drive means includes a coil that generates a magnetic field when energized, a stator and a stay housing that are formed of a magnetic material and covers the core, and a core that faces the stator.
When the coil is energized, a magnetic circuit is formed in the stator, the stator housing and the core, and the core is attracted to the stator side together with the valve member by a magnetic attraction force generated between the stator and the core. The valve member is separated from the valve seat,
The exhaust purifying apparatus , wherein the holding mounting part holds the on-off valve, the driving means, and the nozzle part . The holding mounting part is connected to holding means for holding the functional part, the introducing part, a delivery port for sending a reducing agent from the introducing part to the functional part, and the exhaust system of the internal combustion engine. The exhaust emission control device according to claim 1, further comprising a mounting means. The exhaust purification device according to claim 1 or 2, wherein the holding and mounting portion includes a plurality of housing members divided so as to be capable of housing the functional portion. The exhaust emission control device according to claim 3, wherein the plurality of housing members are coupled to each other. The exhaust emission control device according to claim 4, wherein the functional unit is coupled to any of the plurality of housing members. 6. The exhaust emission control device according to claim 4 or 5, wherein the plurality of housing members, and the functional portion and the housing member are joined together by welding or mechanically. The exhaust purification device according to claim 1 or 2, wherein a liquid-tight seal is provided between the functional unit and the holding and mounting unit. An exhaust purification device mounted on an exhaust system of an internal combustion engine,
An introduction part into which the reducing agent is introduced;
A nozzle part from which the reducing agent introduced from the introduction part is injected;
A function part that is separate from the nozzle part and has an on-off valve for intermittently injecting the reducing agent from the nozzle part, and a driving means for driving the on-off valve;
A holding mounting portion for mounting the functional portion on the exhaust system;
An exhaust emission control device comprising: 9. The exhaust emission control device according to claim 8, wherein the nozzle portion has at least one injection hole that opens to the downstream side of the exhaust flow of the exhaust system. The exhaust purification device according to claim 8 or 9, wherein the nozzle portion is coupled to the holding mounting portion. The exhaust purification device according to claim 8 or 9, wherein the nozzle portion is coupled to the functional portion. The exhaust emission control device according to claim 10 or 11, wherein the nozzle portion and the holding mounting portion or the functional portion are coupled by welding or mechanically. The exhaust emission control device according to claim 8, wherein a liquid-tight seal is provided between the nozzle portion and the functional portion.

Images