JP6231871B2 - Exhaust purification device - Google Patents

Description

  The present invention relates to a reducing agent injection valve and an exhaust purification system.

  In some cases, exhaust gas discharged from an internal combustion engine mounted on a vehicle or the like contains nitrogen oxides (NOx). As one of the exhaust gas purification devices for purifying NOx, a reducing agent is injected on the upstream side of a reduction catalyst provided in an exhaust passage of an internal combustion engine, and a reduction reaction between the reducing agent and NOx is promoted by the catalyst. Some are configured to be decomposed into nitrogen, water, carbon dioxide, etc. and released into the atmosphere.

  As such an exhaust purification device, there is a urea SCR (Selective Catalyst Reduction) system using urea aqueous solution or ammonia water as a reducing agent. In the urea SCR system, a NOx selective reduction catalyst having an ammonia adsorption function is used, ammonia generated by hydrolysis of the reducing agent is adsorbed by the reduction catalyst, and NOx in the exhaust gas flowing into the NOx is converted to ammonia. It is purified by reacting.

  For example, Patent Document 1 below describes a configuration of an addition valve for injecting a reducing agent into an exhaust passage of an internal combustion engine (FIG. 2).

JP 2010-255608 A

  In the SCR system, the reducing agent is injected from the reducing agent injection valve into the exhaust passage. The urea aqueous solution used as the reducing agent has a relatively high melting point and freezes below freezing point. Therefore, when the engine is stopped, etc., it is reduced in the path from the tank storing the reducing agent to the reducing agent injection valve and in the reducing agent injection valve. It is envisaged that the agent will freeze. For this reason, after the engine stops, the urea aqueous solution is sucked back into the storage tank.

  In the conventional addition valve structure described in Patent Document 1, the armature (movable core 43) can be reciprocated in the axial direction within the housing 21. And when opening an addition valve, the movable core 43 is attracted | sucked by the fixed core 42, the needle 26 leaves | separates from the valve seat part 25a, and valve opening is performed. At this time, a minute air gap is usually provided between the movable core 43 and the fixed core 42.

  In the configuration described in Patent Document 1, when sucking back urea water, a minute gap between the movable core 43 and the housing 1, a minute gap between the movable core 43 and the fixed core 42, etc. The urea water remains, and the urea water cannot be completely sucked back into the tank. For this reason, the problem that the remaining urea water freezes below freezing point arises. Even after the engine is stopped, the reducing agent injection valve is exposed to high-temperature heat in the exhaust passage. If the urea water remaining in these gaps is exposed to a high temperature by the heat of the exhaust passage, and then the temperature is lowered, it is assumed that the valve is fixed due to crystallization of urea and a malfunction occurs in the valve operation.

  Furthermore, since the movable core 43 is disposed with a predetermined clearance in the radial direction in the housing 21, the movable core 43 is inclined with respect to the housing 21 within the clearance. Due to this inclination, the gap between the movable core 43 and the housing 21 becomes narrower, and in the region where the gap is narrow, or the region where the movable core 43 and the housing 21 are in close contact with each other, the urea water remains remarkably when sucking back. Become.

  Therefore, the present invention has been made in view of the above problems, and the object of the present invention is to reliably perform sucking back of the reducing agent from the reducing agent injection valve with a simple configuration. It is an object of the present invention to provide a new and improved reducing agent injection valve and exhaust purification system.

  In order to solve the above problems, according to an aspect of the present invention, a reducing agent injected into an exhaust passage of an internal combustion engine is supplied to the inside, and is slidably provided inside the housing and closed. An armature that closes the injection hole of the housing at the time of valve opening and is spaced apart from the injection hole of the housing at the time of valve opening and injects a reducing agent to the outside from the injection hole; and a stopper that approaches or contacts the armature at the time of valve opening There is provided a reducing agent injection valve including a reducing agent passage provided in a portion where the armature and the housing or the stopper are close to each other.

  The armature may have a hollow shape, and the passage may be configured by a hole connecting the outer surface of the armature that slides with the inner surface of the housing and the hollow portion of the armature.

  The passage may be constituted by a groove provided on an outer surface of the armature that slides with an inner surface of the housing.

  Moreover, the said channel | path may be comprised from the groove | channel provided in the end surface which adjoins or contacts the said stopper of the said armature.

  Moreover, the said channel | path may be comprised from the groove | channel provided in the end surface which adjoins or contacts the said armature of the said stopper.

  The passage may be constituted by a groove provided on an inner surface of the housing that slides with the armature.

  In order to solve the above problems, according to another aspect of the present invention, a reducing agent injection valve that injects a reducing agent into an exhaust passage of an internal combustion engine, and a reducing agent supplied to the reducing agent injection valve are stored. A storage tank, and a pump that supplies the reducing agent from the storage tank to the reducing agent injection valve in the first state, and sucks the reducing agent back from the reducing agent injection valve to the storage tank in the second state; The reducing agent injection valve includes a housing in which a reducing agent is supplied, and is slidably provided inside the housing. The reducing agent injection valve closes the injection hole of the housing when the valve is closed, and the housing when the valve is opened. An armature that injects the reducing agent to the outside from the injection hole apart from the injection hole, a stopper that the armature approaches or contacts when the valve is opened, the armature and the housing, or the stopper There exhaust gas purification system and a passage of the reducing agent is provided in a portion adjacent are provided.

  The armature may have a hollow shape, and the passage may be configured by a hole connecting the outer surface of the armature that slides with the inner surface of the housing and the hollow portion of the armature.

  The passage may be constituted by a groove provided on an outer surface of the armature that slides with an inner surface of the housing.

  Moreover, the said channel | path may be comprised from the groove | channel provided in the end surface which adjoins or contacts the said stopper of the said armature.

  Moreover, the said channel | path may be comprised from the groove | channel provided in the end surface which adjoins or contacts the said armature of the said stopper.

  The passage may be constituted by a groove provided on an inner surface of the housing that slides with the armature.

  According to the present invention, it is possible to reliably suck back the reducing agent from the reducing agent injection valve with a simple configuration.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an example of an internal combustion engine exhaust purification apparatus and its peripheral configuration according to an embodiment of the present invention. It is a schematic diagram which shows the structure of a reducing agent injection valve. It is a schematic diagram for demonstrating the basic structure of an armature. It is a schematic diagram which shows the area | region where a reducing agent tends to stay when sucking back a reducing agent. It is a schematic diagram which shows the area | region where a reducing agent tends to stay when sucking back a reducing agent. It is a schematic diagram which shows the area | region where a reducing agent tends to stay when sucking back a reducing agent. It is a schematic diagram which shows the example which provided the some channel | path (hole) which connects the outer peripheral surface of an armature, and the hollow part inside an armature. It is a schematic diagram which shows the example which provided the groove-shaped several channel | path in the outer peripheral surface of an armature. It is a schematic diagram which shows the example which provided the groove-shaped channel | path in the end surface of an armature. It is a schematic diagram which shows the example which provided the groove-shaped channel | path in the end surface of a stopper. It is a schematic diagram which shows the example which provided the groove-shaped channel | path in the inner surface of the housing.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

1. FIG. 1 shows an example of the configuration of an exhaust emission control device 10 for an internal combustion engine according to an embodiment of the present invention and its surroundings. This exhaust purification device 10 is connected to the exhaust passage 11 of the internal combustion engine 5, and includes a reduction catalyst 20, a reducing agent injection device 30, a control device 60 and the like, and exhaust gas discharged from the internal combustion engine 5. It is configured as a urea SCR system that purifies nitrogen oxide (NOx) therein using a urea aqueous solution as a reducing agent. However, the reducing agent that can be used in the present embodiment is not limited to the urea aqueous solution, and may be any one that generates ammonia, such as ammonia water.

  The internal combustion engine 5 is controlled by an ECU (Engine Control Unit) 50. The control device 60 receives control data relating to the control of the internal combustion engine 5 from the ECU 50 via a CAN (Control Area Network) bus system.

  In the exhaust passage 11, an oxidation catalyst 12 (DOC) is disposed between the internal combustion engine 5 and the reduction catalyst 20. The oxidation catalyst 12 has a function of oxidizing hydrocarbons (HC) and carbon monoxide (CO) in the exhaust gas. A known catalyst is appropriately used as the oxidation catalyst 12.

The reduction catalyst 20 used in the exhaust purification device 10 of the present embodiment adsorbs ammonia generated by hydrolysis of the urea aqueous solution injected into the exhaust passage 11 and promotes the reduction reaction between ammonia and NOx. It has a function. Specifically, in the reduction catalyst 20, ammonia (NH ₃ ) produced by the decomposition of urea in the urea aqueous solution reacts with NOx, so that NOx becomes nitrogen (N ₂ ) and water (H ₂ O). Is broken down into A known catalyst is appropriately used as the reduction catalyst 20.

  Further, a NOx sensor 14 for detecting the NOx concentration in the exhaust gas is provided on the downstream side of the reduction catalyst 20. The sensor signal of the NOx sensor 14 is transmitted to the control device 60, and the control device 60 calculates the NOx concentration in the exhaust gas based on this sensor signal. Further, an exhaust temperature sensor 13 for detecting the temperature of the exhaust gas is provided on the upstream side of the reduction catalyst 20.

(2) Reducing agent injection device The reducing agent injection device 30 is mainly configured by a storage tank 31, a reducing agent injection valve 70, a pump 41, and the like. The storage tank 31 and the pump 41 are connected by a first reducing agent supply passage 57, and the pump 41 and the reducing agent injection valve 70 are connected by a second reducing agent supply passage 58. Among these, the pressure sensor 43 is provided in the second reducing agent supply passage 58. The sensor signal of the pressure sensor 43 is transmitted to the control device 60, and the control device 60 calculates the pressure in the second reducing agent supply passage 58 based on this sensor signal.

  The storage tank 31 is provided with a tank temperature sensor 18 for detecting the temperature of the urea aqueous solution. An electric pump that is driven and controlled by the control device 60 is used as the pump 41. In the present embodiment, the pump 41 is configured such that its output is feedback-controlled so that the pressure in the second reducing agent supply passage 58 detected by the pressure sensor 43 is maintained at a predetermined value. .

  The reducing agent injection valve 70 is an electromagnetically driven on / off valve whose opening / closing is controlled by the control device 60, and is fixed to the exhaust passage 11 upstream of the reduction catalyst 20. The reducing agent injection valve 70 is basically subjected to energization control in a state where the pressure in the second reducing agent supply passage 58 is maintained at a target value. Specifically, the injection amount of the reducing agent into the exhaust passage 11 is adjusted by setting the valve opening DUTY ratio during a predetermined DUTY cycle in accordance with the instructed injection amount obtained by calculation. The command injection amount is determined according to the flow rate of nitrogen oxides in the exhaust gas and the ammonia adsorption amount in the reduction catalyst 20.

  In the present embodiment, the pump 41 can rotate in either the forward or reverse direction. The urea aqueous solution in the storage tank 31 is sucked up by the forward rotation of the pump 41, and the urea aqueous solution is supplied to the reducing agent injection valve 70. Further, the urea aqueous solution is sucked back from the reducing agent injection valve 70 to the storage tank 31 by the reverse rotation of the pump 41. A state in which the reducing agent (urea aqueous solution) is supplied to the reducing agent injection valve 70 is referred to as a first state, and a state in which the reducing agent is sucked back from the reducing agent injection valve 70 is referred to as a second state. Supply of the reducing agent to the reducing agent injection valve 70 (first state) and sucking back of the reducing agent from the reducing agent injection valve 70 (second state) indicate the rotational directions of the pump 41 in both states. The same may be performed by controlling the flow path switching valve. As such a basic configuration of the reducing agent injection device 30, a known configuration can be used.

2. Configuration of Reducing Agent Injection Valve In the SCR system, after the internal combustion engine 5 is stopped, the pump 41 is reversely rotated to return the reducing agent filled in the path from the storage tank 31 to the reducing agent injection valve 70 into the storage tank 31. (Second state). Thereby, it can suppress that the reducing agent with which the path | route from the storage tank 31 to the reducing agent injection valve 70 is frozen at low temperature. Such an operation of returning the reducing agent to the storage tank 31 can also be performed when an error occurs, such as when an error occurs in the CAN signal. When returning the reducing agent to the storage tank 31, the reducing agent injection valve 70 is opened.

  FIG. 2 is a schematic diagram showing the configuration of the reducing agent injection valve 70. As shown in FIG. 2, the reducing agent injection valve 70 includes a housing 72, an armature 74, a stopper 76, a compression spring 78, a coil 80, an adjustment sleeve 82, and a filter 84. The housing 72 constitutes a main body of the reducing agent injection valve 70, and an armature 74, a stopper 76, and a compression spring 78 are disposed in the housing 72.

  More specifically, the armature 74 and the stopper 76 are inserted into the cylindrical interior of the housing 72, the armature 74 is movable in the axial direction, and the stopper 76 is fixed to the housing 72. The armature 74 and the stopper 76 are made of metal such as iron. A coil 80 is disposed on the outer periphery of the stopper 76.

  The adjustment sleeve 82 is fixed to the stopper 76. One end of the compression spring 78 is in contact with the adjustment sleeve 82, and the other end is in contact with the contact surface 74 a of the armature 74. The armature 74, the stopper 76, and the adjustment sleeve 82 all have a space inside. The stopper 76 and the adjustment sleeve 82 have a hollow pipe shape, and the armature 74 has a hollow shape except for the tip 74h.

  The tip 74h of the armature 74 has a spherical shape. On the other hand, an orifice 72 a is provided at the tip of the housing 72. When the coil 80 is not energized, the armature 74 is urged toward the distal end side of the housing 72 by the urging force of the compression spring 78, and the distal end portion 74 h of the armature 74 is provided inside the distal end of the housing 72. 72b abuts.

  On the other hand, when the coil 80 is energized, the armature 74 is attracted toward the stopper 76 by the magnetic force, and the end surface 74b of the armature 74 and the end surface 76a of the stopper 76 come close to each other. At this time, a portion for restricting the movement of the armature 74 is separately provided so that a predetermined air gap is provided between the end surface 74 b of the armature 74 and the end surface 76 a of the stopper 76. The gap when the end surface 74b and the end surface 76a are close to each other can be set to a value of about 20 μm, for example. Thereby, the magnetic force by the coil 80 at the time of attraction | suction can fully be enlarged.

  Further, the end surface 74b of the armature 74 and the end surface 76a of the stopper 76 may be in contact with each other. In this case, by forming a plating layer having a predetermined thickness on the end surface 74b of the armature 74, the gap of about 20 μm can be eliminated and the end surface 74b and the end surface 76a can be in contact with each other.

  The reducing agent is supplied from the direction of arrow A <b> 1 in FIG. 2, passes through the filter 84, and is supplied to the adjustment sleeve 82. Since the adjustment sleeve 82 and the stopper 76 have a hollow pipe shape, the reducing agent passes through the adjustment sleeve 82 and the stopper 76 and is supplied to the armature 74.

  As shown in FIG. 2, the armature 74 is provided with a hole 74i for connecting the inside and the outside. The reducing agent is supplied to the inside of the armature 74 from the stopper 76 side, is sent to the outside of the armature 74 through the hole 74i, and is sent in the direction of the tip end portion 74h.

  As described above, when the coil 80 is not energized, the tip 74 h of the armature 74 is in contact with the valve seat 72 b provided inside the tip of the housing 72. Therefore, the reducing agent sent from the hole 74i in the direction of the tip 74h is not injected from the orifice 72a.

  On the other hand, when the coil 80 is energized, the armature 74 is attracted toward the stopper 76, and the end surface 74b of the armature 74 and the end surface 76a of the stopper 76 come close to each other. As a result, the tip 74h of the armature 74 is separated from the valve seat 72b, and the reducing agent is injected to the outside of the housing 72 through the orifice 72a.

  FIG. 3 is a schematic diagram for explaining the basic configuration of the armature 74. As shown in FIG. 3, the armature 74 is provided with an outer peripheral surface 74c that slides with respect to the inner surface 72d of the housing 72 on the end surface 74b side. The clearance between the outer peripheral surface 74c and the inner surface 72d of the housing 72 is set to a predetermined value (for example, about 100 μm). In the outer peripheral surface 74c, the clearance between the housing 72 and the housing 72 is a predetermined value within the range of the length D on the end surface 74b side, and in other regions, the outer peripheral surface 74c and the inner surface of the housing 72 The clearance between 72d is set to a value larger than a predetermined value.

  FIGS. 4 to 6 show a state in which the armature 74 is inserted into the housing 72, and are schematic views showing regions where the reducing agent tends to stay when the reducing agent is sucked back. Since the clearance is provided between the inner surface 72d of the housing 72 and the outer peripheral surface 74c, the central axis C2 of the armature 74 may be inclined with respect to the central axis C1 of the inner surface 72d of the housing 72. FIG. 4 shows a case where the center axis C2 of the armature 74 is not inclined with respect to the center axis C1 of the inner surface 72d of the housing 72. In this case, the reducing agent tends to accumulate on the lower side (region R1) in the gravity direction in the gap between the inner surface 72d of the housing 72 and the outer peripheral surface 74c. This is because the clearance between the inner surface 72d of the housing 72 and the outer peripheral surface 74c is the smallest on the lower side in the gravity direction, and the reducing agent moves in the gravity direction.

  FIG. 5 shows a case where the center axis C2 of the armature 74 is inclined with respect to the center axis C1 of the inner surface 72d of the housing 72, and the tip 74h of the armature 74 is moved upward. In this case, the clearance between the armature 74 and the inner surface 72d of the housing 72 is narrowed in the region R2 shown in FIG. 5, and the reducing agent tends to accumulate in the region R2.

  FIG. 6 shows a case where the center axis C2 of the armature 74 is inclined with respect to the center axis C1 of the inner surface 72d of the housing 72, and the tip 74h of the armature 74 moves downward. In this case, the clearance between the armature 74 and the inner surface 72d of the housing 72 is narrowed in the region R3 shown in FIG. 6, and the reducing agent tends to accumulate in the region R3.

  As described above, when the reducing agent is sucked back into the storage tank 31, the reducing agent easily collects in a region where the clearance between the armature 74 and the inner surface 72 d of the housing 72 is narrow. Further, when the reducing agent is sucked back into the storage tank 31, the reducing agent easily collects between the end surface 74 b of the armature 74 and the end surface 76 a of the stopper 76. For this reason, it is assumed that the reducing agent remaining without being sucked back is frozen below freezing point or crystallized by exhaust heat.

  For this reason, in the present embodiment, in the housing 72, the armature 74, and the stopper 76, a passage through which the reducing agent passes is provided at a site where the reducing agent contacts. Hereinafter, a specific configuration of the passage through which the reducing agent passes will be described with reference to FIGS.

  FIG. 7 is a schematic view showing an example in which a plurality of passages 74d (holes) that connect the outer peripheral surface 74c of the armature 74 and the hollow portion inside the armature 74 are provided. By providing the passage 74d, when the reducing agent is sucked back, the reducing agent flows in the direction of the arrow shown in FIG. Thereby, in particular, the reducing agent staying between the outer peripheral surface 74c of the armature 74 and the inner surface 72d of the housing 72 flows through the passage 74d to the hollow portion inside the armature 74, and passes through the hollow portion of the stopper 76 and the sleeve 82. And sucked back to the storage tank 31 side. Therefore, the reducing agent staying between the armature 74 and the housing 72 can be surely sucked back.

  FIG. 8 is a schematic diagram showing an example in which a plurality of groove-shaped or slit-shaped passages 74 e are provided on the outer peripheral surface 74 c of the armature 74. In the example shown in FIG. 8, the passage 74 e is provided so as to extend in the circumferential direction of the outer peripheral surface 74 c and the axial direction of the armature 74. By providing the passage 74e, when the reducing agent is sucked back, the reducing agent flows in the direction of the arrow shown in FIG. Thereby, in particular, the reducing agent staying between the outer peripheral surface 74c of the armature 74 and the inner surface 72d of the housing 72 flows into the hollow portion inside the armature 74 through the passage 74e, and passes through the hollow portion of the stopper 76 and the sleeve 82. And sucked back to the storage tank 31 side. Therefore, the reducing agent staying between the armature 74 and the housing 72 can be surely sucked back.

  FIG. 9 is a schematic view showing an example in which groove-like or slit-like passages 74f and 74g are provided on the end face 74b of the armature 74. As shown in FIG. In the example shown in FIG. 9, the passage 74f is provided on the end surface 74b, and is provided in an annular shape along the outer peripheral surface 74c. Further, the passage 74g is provided so as to connect the outer peripheral surface 74c and the inner hollow portion at four locations of the annular passage 74f. By providing the passages 74f and 74g, it is possible to reliably suck back the reducing agent staying between the end surface 74b and the end surface 76a of the stopper 76. Further, by providing the passages 74f and 74g, the reducing agent staying between the outer peripheral surface 74c and the inner surface 72d of the housing 72 flows through the passages 74f and 74g to the hollow portion inside the armature 74. It is possible to reliably suck back the reducing agent staying between the housing 72 and the housing 72.

  FIG. 10 is a schematic view showing an example in which groove-like or slit-like passages 76b and 76c are provided on the end surface 76a of the stopper 76. As shown in FIG. In the example shown in FIG. 10, the passage 76 b is provided on the end surface 76 a and is provided in an annular shape along the outer peripheral surface of the stopper 76. Further, the passage 76c is provided so as to connect the outer peripheral surface of the stopper 76 and the inner hollow portion at four locations of the annular passage 76b. By providing the passages 76b and 76c, the reducing agent staying between the outer peripheral surface 74c and the inner surface 72d of the housing 72 flows through the passages 76b and 76c to the hollow portion inside the armature 74. It is possible to reliably suck back the reducing agent staying between 74b and the end surface 76a of the stopper 76.

  FIG. 11 is a schematic view showing an example in which a groove-like or slit-like passage 72c is provided on the inner surface 72d of the housing 72. As shown in FIG. In the example shown in FIG. 11, the passage 72 c is provided so as to extend in the axial direction of the armature 74. When the reducing agent is sucked back by providing the passage 72c, the reducing agent flows in the passage 72c toward the stopper 76 as in FIG. Thereby, in particular, the reducing agent staying between the outer peripheral surface 74c of the armature 74 and the inner surface 72d of the housing 72 flows to the stopper 76 side through the passage 72c and is sucked back to the storage tank 41 side. Therefore, the reducing agent staying between the armature 74 and the housing 72 can be surely sucked back.

  In addition, the structure shown in FIGS. 7-11 may be comprised independently, and may be comprised combining several.

  As described above, according to the present embodiment, since the passage through which the reducing agent passes is provided at the site where the reducing agent in the reducing agent injection valve 70 contacts, it is ensured that the reducing agent remains at the time of sucking back. Can be deterred. Therefore, it is possible to reliably suppress the remaining reducing agent from being frozen or crystallized by heat. As a result, it is possible to surely prevent the malfunction of the operation of the reducing agent injection valve 70 from occurring.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

5 Internal combustion engine 31 Storage tank 41 Pump 70 Reducing agent injection valve 72 Housing 72d Inner surface 72a Orifice 74 Armature 76 Stopper 74b End surface 74c Outer peripheral surface 74d, 74e, 74f, 74g Passage stopper 76
End face 76a

Claims (10)

A housing in which a reducing agent injected into the exhaust passage of the internal combustion engine is supplied;
An armature that is slidably provided inside the housing, closes the injection hole of the housing when the valve is closed, and separates from the injection hole of the housing when the valve is opened to inject the reducing agent to the outside from the injection hole; ,
A stopper that the armature approaches or contacts when the valve is opened; and
A passage of a reducing agent provided at a site where the armature and the housing or the stopper are close to each other;
Equipped with a,
In the reducing agent injection valve in which the reducing agent is supplied from the stopper in the direction of the armature,
The armature is a hollow shape, said passage is characterized Rukoto constituted by holes connecting the outer surface and the hollow portion of the armature of the armature to the inner surface and the sliding of the housing, the reducing agent injection valve.   A housing in which a reducing agent injected into the exhaust passage of the internal combustion engine is supplied;
  An armature that is slidably provided inside the housing, closes the injection hole of the housing when the valve is closed, and separates from the injection hole of the housing when the valve is opened to inject the reducing agent to the outside from the injection hole; ,
  A stopper that the armature approaches or contacts when the valve is opened; and
  A passage of a reducing agent provided at a site where the armature and the housing or the stopper are close to each other;
  With
  In the reducing agent injection valve in which the reducing agent is supplied from the stopper in the direction of the armature,
The passage includes a plurality of circumferential grooves on the outer circumferential surface provided on an outer circumferential surface of the armature that slides on an inner surface of the housing and a plurality of grooves in the axial direction of the armature. , Reducing agent injection valve. A housing in which a reducing agent injected into the exhaust passage of the internal combustion engine is supplied;
  An armature that is slidably provided inside the housing, closes the injection hole of the housing when the valve is closed, and separates from the injection hole of the housing when the valve is opened to inject the reducing agent to the outside from the injection hole; ,
  A stopper that the armature approaches or contacts when the valve is opened; and
  A passage of a reducing agent provided at a site where the armature and the housing or the stopper are close to each other;
  With
In the reducing agent injection valve in which the reducing agent is supplied in the direction of the armature from the stopper.
  The reducing agent injection valve according to claim 1, wherein the passage is constituted by a groove provided in an end face that is close to or in contact with the stopper of the armature.   A housing in which a reducing agent injected into the exhaust passage of the internal combustion engine is supplied;
  An armature that is slidably provided inside the housing, closes the injection hole of the housing when the valve is closed, and separates from the injection hole of the housing when the valve is opened to inject the reducing agent to the outside from the injection hole; ,
  A stopper that the armature approaches or contacts when the valve is opened; and
  A passage of a reducing agent provided at a site where the armature and the housing or the stopper are close to each other;
  With
In the reducing agent injection valve in which the reducing agent is supplied in the direction of the armature from the stopper.
The reducing agent injection valve according to claim 1, wherein the passage is configured by a groove provided on an end surface of the stopper that is close to or in contact with the armature.   A housing in which a reducing agent injected into the exhaust passage of the internal combustion engine is supplied;
  An armature that is slidably provided inside the housing, closes the injection hole of the housing when the valve is closed, and separates from the injection hole of the housing when the valve is opened to inject the reducing agent to the outside from the injection hole; ,
  A stopper that the armature approaches or contacts when the valve is opened; and
  A passage of a reducing agent provided at a site where the armature and the housing or the stopper are close to each other;
  With
In the reducing agent injection valve in which the reducing agent is supplied in the direction of the armature from the stopper.
The reducing agent injection valve according to claim 1, wherein the passage is configured by a groove provided on an inner surface of the housing that slides with the armature. A reducing agent injection valve for injecting the reducing agent into the exhaust passage of the internal combustion engine;
A storage tank for storing a reducing agent supplied to the reducing agent injection valve;
A pump for supplying a reducing agent from the storage tank to the reducing agent injection valve in the first state, and a pump for sucking the reducing agent back from the reducing agent injection valve to the storage tank in the second state;
The reducing agent injection valve is
A housing in which a reducing agent is supplied;
An armature that is slidably provided inside the housing, closes the injection hole of the housing when the valve is closed, and separates from the injection hole of the housing when the valve is opened to inject the reducing agent to the outside from the injection hole; ,
A stopper that the armature approaches or contacts when the valve is opened; and
A passage of a reducing agent provided at a site where the armature and the housing or the stopper are close to each other;
Equipped with a,
In the first state, the reducing agent is supplied from the stopper toward the armature in the reducing agent injection valve,
The armature is a hollow shape, said passage is characterized Rukoto constituted by holes connecting the outer surface and the hollow portion of the armature of the armature to the inner surface and the sliding of the housing, an exhaust purification system.   A reducing agent injection valve for injecting the reducing agent into the exhaust passage of the internal combustion engine;
  A storage tank for storing a reducing agent supplied to the reducing agent injection valve;
  A pump for supplying a reducing agent from the storage tank to the reducing agent injection valve in the first state, and a pump for sucking the reducing agent back from the reducing agent injection valve to the storage tank in the second state;
  The reducing agent injection valve is
  A housing in which a reducing agent is supplied;
  An armature that is slidably provided inside the housing, closes the injection hole of the housing when the valve is closed, and separates from the injection hole of the housing when the valve is opened to inject the reducing agent to the outside from the injection hole; ,
  A stopper that the armature approaches or contacts when the valve is opened; and
  A passage of a reducing agent provided at a site where the armature and the housing or the stopper are close to each other;
  With
In the first state, the reducing agent is supplied from the stopper toward the armature in the reducing agent injection valve,
The passage includes a plurality of circumferential grooves on the outer circumferential surface provided on an outer circumferential surface of the armature that slides on an inner surface of the housing and a plurality of grooves in the axial direction of the armature. , Exhaust purification system.   A reducing agent injection valve for injecting the reducing agent into the exhaust passage of the internal combustion engine;
  A storage tank for storing a reducing agent supplied to the reducing agent injection valve;
  A pump for supplying a reducing agent from the storage tank to the reducing agent injection valve in the first state, and a pump for sucking the reducing agent back from the reducing agent injection valve to the storage tank in the second state;
  The reducing agent injection valve is
  A housing in which a reducing agent is supplied;
  An armature that is slidably provided inside the housing, closes the injection hole of the housing when the valve is closed, and separates from the injection hole of the housing when the valve is opened to inject the reducing agent to the outside from the injection hole; ,
  A stopper that the armature approaches or contacts when the valve is opened; and
  A passage of a reducing agent provided at a site where the armature and the housing or the stopper are close to each other;
  With
In the first state, the reducing agent is supplied from the stopper toward the armature in the reducing agent injection valve,
2. The exhaust gas purification system according to claim 1, wherein the passage is configured by a groove provided on an end face that is close to or in contact with the stopper of the armature.   A reducing agent injection valve for injecting the reducing agent into the exhaust passage of the internal combustion engine;
  A storage tank for storing a reducing agent supplied to the reducing agent injection valve;
  A pump for supplying a reducing agent from the storage tank to the reducing agent injection valve in the first state, and a pump for sucking the reducing agent back from the reducing agent injection valve to the storage tank in the second state;
  The reducing agent injection valve is
  A housing in which a reducing agent is supplied;
  An armature that is slidably provided inside the housing, closes the injection hole of the housing when the valve is closed, and separates from the injection hole of the housing when the valve is opened to inject the reducing agent to the outside from the injection hole; ,
  A stopper that the armature approaches or contacts when the valve is opened; and
  A passage of a reducing agent provided at a site where the armature and the housing or the stopper are close to each other;
  With
In the first state, the reducing agent is supplied from the stopper toward the armature in the reducing agent injection valve,
2. The exhaust gas purification system according to claim 1, wherein the passage is constituted by a groove provided on an end surface of the stopper that is close to or in contact with the armature.   A reducing agent injection valve for injecting the reducing agent into the exhaust passage of the internal combustion engine;
  A storage tank for storing a reducing agent supplied to the reducing agent injection valve;
  A pump for supplying a reducing agent from the storage tank to the reducing agent injection valve in the first state, and a pump for sucking the reducing agent back from the reducing agent injection valve to the storage tank in the second state;
  The reducing agent injection valve is
  A housing in which a reducing agent is supplied;
  An armature that is slidably provided inside the housing, closes the injection hole of the housing when the valve is closed, and separates from the injection hole of the housing when the valve is opened to inject the reducing agent to the outside from the injection hole; ,
  A stopper that the armature approaches or contacts when the valve is opened; and
  A passage of a reducing agent provided at a site where the armature and the housing or the stopper are close to each other;
  With
In the first state, the reducing agent is supplied from the stopper toward the armature in the reducing agent injection valve,
The exhaust gas purification system according to claim 1, wherein the passage is configured by a groove provided on an inner surface of the housing that slides with the armature.

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