JP2010065588A - Urea water injection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a urea water injection system for securing sure injection of urea water, by reducing clogging of a nozzle port caused by deposit of urea. <P>SOLUTION: This injection system 11 has a valve member 22 and a cylindrical member 21 slidable in the axial direction, on the outer peripheral side of the valve member 22 for opening the nozzle port 37 on an outer wall 36. The cylindrical member 21 opens-closes the nozzle port 37 by moving in the axial direction. Thus, even if a crystal 40 of the urea is deposited on the valve member 22 around the nozzle port 37, the deposited crystal of the urea is removed by the movement of the cylindrical member 21 when injecting the urea water or stopping injection. Thus, the sure injection of the urea water is secured by reducing the clogging of the nozzle port 37 caused by the deposit of the urea. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a urea water injection device that injects urea into exhaust gas flowing through an exhaust passage of an internal combustion engine.

  An SCR (Selective Catalytic Reduction) system is known as an exhaust purification device that reduces NOx discharged from an internal combustion engine, particularly a diesel engine. An exhaust gas purification apparatus using an SCR system selectively reduces NOx contained in exhaust gas to nitrogen or water by, for example, injecting urea or ammonia as a reducing agent. By the way, urea contained in urea water precipitates as crystals when water evaporates. For this reason, the precipitated urea accumulates in the exhaust pipe portion and the injection valve that form the exhaust passage, and causes a malfunction. Therefore, in Patent Document 1, pressurized air is injected into the exhaust pipe portion to reduce urea adhering to the inner wall of the exhaust pipe portion.

However, in the case of Patent Document 1, although the urea crystals adhering to the inner wall of the exhaust pipe portion are reduced, it is difficult to reduce the urea crystals adhering to the vicinity of the nozzle holes for injecting urea water. Urea deposited in the vicinity of the urea water injection device for injecting urea water in this way causes clogging of the nozzle holes. As a result, there is a problem that the urea water to be injected is insufficient or the urea water injection itself stops.
JP 2005-273579 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a urea water injection device that reduces the clogging of nozzle holes associated with the precipitation of urea and ensures reliable injection of urea water.

  In the first aspect of the present invention, the nozzle hole through which the urea water is injected opens in the outer wall of the valve member provided on the inner peripheral side of the cylindrical member. The valve member having an injection hole in the outer wall and the cylindrical member provided on the outer peripheral side of the valve member relatively move in the axial direction. Therefore, the nozzle hole opened in the outer wall of the valve member is opened and closed by the outer cylindrical member. Thereby, when injecting urea water from a nozzle hole, it is necessary for a valve member to protrude further to the exhaust passage side from the front-end | tip of a cylinder member. As a result, the relative movement of the valve member and the cylindrical member causes urea crystals deposited around the nozzle hole due to urea water adhering to the nozzle hole to move around the outer periphery of the nozzle hole. It is scraped off by the valve member. Therefore, the clogging of the nozzle hole due to urea precipitation can be reduced, and reliable injection of urea water can be ensured.

According to the second aspect of the present invention, of the relatively moving valve member and cylindrical member, the valve member is fixed to the exhaust pipe portion, and the cylindrical member is driven in the axial direction. Therefore, the cylindrical member located on the outer peripheral side of the valve member opens and closes the injection hole that opens in the outer wall of the valve member. Therefore, the clogging of the nozzle hole due to urea precipitation can be reduced, and reliable injection of urea water can be ensured.
According to the third aspect of the present invention, the drive unit drives the cylindrical member. Therefore, the structure of the drive unit can be simplified.
According to the fourth aspect of the present invention, of the relatively moving valve member and cylindrical member, the cylindrical member is fixed to the exhaust pipe portion, and the valve member is driven in the axial direction. Therefore, the cylindrical member located on the outer peripheral side of the valve member opens and closes the injection hole that opens in the outer wall of the valve member. Therefore, the clogging of the nozzle hole due to urea precipitation can be reduced, and reliable injection of urea water can be ensured.

In the invention according to claim 5, the drive unit drives the valve member. Therefore, the drive unit can drive the valve member with a relatively large force. Therefore, the urea crystals adhering to the outer wall of the valve member can be more reliably removed.
In the invention according to claim 6 or 7, the valve member has a contact portion that contacts the tip of the cylindrical member. When the contact portion comes into contact with the tip of the cylindrical member, relative movement of the valve member and the cylindrical member in the axial direction is limited. Therefore, when the nozzle hole is closed with the cylindrical member and urea water is not injected from the nozzle hole, the relative positions of the cylindrical member and the valve member can be defined.

  In the invention according to claim 8, the valve member forms a main injection hole and a sub injection hole in the outer wall. For example, when the flow rate of exhaust gas is small, the injection amount of urea water to be injected is smaller than when the flow rate of exhaust gas is large. Therefore, by controlling the relative amount of movement between the valve member and the cylinder member according to the flow rate of exhaust gas, that is, the operating state of the internal combustion engine, the urea water is only in the main nozzle hole on the tip side, or the main nozzle hole and the sub nozzle hole. It is injected from both sides. That is, the urea water injection amount is adjusted by controlling the relative movement amount of the valve member and the cylindrical member. Therefore, an appropriate amount of urea water can be injected according to the operating state of the internal combustion engine.

Hereinafter, a plurality of embodiments of a urea water injection device according to the present invention will be described with reference to the drawings. Note that, in a plurality of embodiments, substantially the same components are denoted by the same reference numerals, and description thereof is omitted.
(First embodiment)
FIG. 1 shows an exhaust purification system to which a urea water injection device (hereinafter referred to as “injection device”) according to a first embodiment of the present invention is applied. The exhaust purification system 10 includes an injection device 11 and a urea water supply device (hereinafter referred to as “supply device”) 12. The exhaust purification system 10 decomposes NOx contained in exhaust gas flowing through an exhaust passage 13 of an internal combustion engine (not shown) using urea water supplied from the supply device 12 and injected from the injection device 11. As the internal combustion engine, for example, a diesel engine, a gasoline engine, a gas turbine engine, or the like is applied. The exhaust pipe portion 14 forms an exhaust passage 13 and one end thereof is connected to an internal combustion engine (not shown). Further, the end of the exhaust pipe 14 opposite to the internal combustion engine is open to the atmosphere.

The exhaust purification system 10 has an SCR catalyst (not shown) on the side closer to the atmosphere than the injector 11, that is, on the downstream side of the injector 11 in the exhaust flow direction. The exhaust purification system 10 may include not only an SCR catalyst but also various catalysts and filters such as an oxidation catalyst, a three-way catalyst, an ammonia oxidation catalyst, or a DPF (Diesel Particulate Filter). The exhaust pipe portion 14 has a cylindrical shape and forms an exhaust passage 13 inside. Exhaust gas discharged from the internal combustion engine is discharged into the atmosphere via an exhaust passage 13 formed by the exhaust pipe portion 14.
The supply device 12 includes a urea water tank 15, a urea water pump 16, and a urea water pipe portion 17. The urea water tank 15 stores urea water, that is, an aqueous solution of urea. The urea water pump 16 supplies urea water stored in the urea water tank 15 to the injection device 11. The urea water pipe portion 17 connects the urea water tank 15 and the injection device 11.

  The exhaust purification system 10 includes a control device 18 such as an ECU (Electronic Control Unit). The control device 18 has a microcomputer composed of a CPU, ROM and RAM (not shown). The control device 18 is connected to, for example, an accelerator opening sensor or a rotational speed sensor (not shown), and detects an operating state of an internal combustion engine (not shown) based on a signal output from the accelerator opening sensor or the rotational speed sensor. . The control device 18 controls the injection device 11 and the urea water pump 16 based on the detected operating state of the internal combustion engine. Thereby, the control device 18 controls the pressure and flow rate of the urea water supplied from the urea water tank 15 to the injection device 11 and the injection timing based on the operating state of the internal combustion engine.

  The injection device 11 is provided downstream of the internal combustion engine in the exhaust flow direction in the exhaust passage 13 and upstream of an SCR catalyst (not shown). The injection device 11 injects urea water into the exhaust flowing through the exhaust passage 13. Thereby, the urea water injected from the injection device 11 is mixed with the exhaust gas and flows into the SCR catalyst. As shown in FIGS. 1 to 3, the injection device 11 includes a cylindrical member 21, a valve member 22, and a drive unit 23. The cylindrical member 21 is formed in a cylindrical shape, and accommodates the valve member 22 inside in a slidable manner. The tubular member 21 is provided through the exhaust pipe portion 14, and the tip projects into the exhaust passage 13. The cylinder member 21 is provided in the exhaust pipe portion 14 so as to be movable in its own axial direction, that is, in the radial direction of the exhaust pipe portion 14. The cylindrical member 21 has a flange 24 that protrudes annularly radially outward at an end on the drive unit 23 side.

The valve member 22 is provided inside the cylindrical member 21. The valve member 22 is assembled integrally with the drive unit 23 and is fixed to the exhaust pipe unit 14. The valve member 22 is provided coaxially with the cylindrical member 21, and the tip projects into the exhaust passage 13. The valve member 22 assembled integrally with the drive unit 23 is fixed to the exhaust pipe unit 14. Thereby, the valve member 22 does not move with respect to the exhaust pipe portion 14.
The valve member 22 has a large-diameter portion 25 having a larger outer diameter than other portions at the tip. The large diameter portion 25 protrudes radially outward from the other portion of the valve member 22. The large-diameter portion 25 has an end surface on the drive portion 23 side that contacts the tip 26 of the cylindrical member 21. That is, the large diameter portion 25 has a contact portion 27 that contacts the cylindrical member 21 on the drive portion 23 side. The cylindrical member 21 is in contact with the contact portion 27, so that the movement to the side opposite to the drive portion 23, that is, the exhaust passage 13 side is restricted.

  The drive unit 23 includes a coil 31, a core 32, and an elastic member 33. The coil 31 is connected to the control device 18 and generates a magnetic field when energized from the control device 18. When a magnetic field is generated by energizing the coil 31, a magnetic attractive force is generated between the magnetic core 32 that houses the coil 31 and the cylindrical member 21. Therefore, when the coil member 31 is energized by forming the cylindrical member 21 with a magnetic material, the cylindrical member 21 moves to the coil 31 side. The cylinder member 21 is not limited to a magnetic material, and may be formed of a non-magnetic material. In this case, a magnetic attractive force is generated between the core 32 and the core 32 by forming a part of the core 32 with a magnetic material or providing a magnetic material at the end of the core 32. The elastic member 33 is constituted by a spring member such as a coil spring, for example. The elastic member 33 has one end in contact with the core 32 and the other end in contact with the flange 24 of the cylindrical member 21. The elastic member 33 applies forces in directions away from each other between the core 32 and the cylindrical member 21. That is, the elastic member 33 applies a force in the direction opposite to the magnetic attractive force generated by the coil 31. Thereby, when the coil 31 is not energized, the cylindrical member 21 is pressed against the side opposite to the coil 31 by the elastic member 33, that is, the exhaust passage 13 side. Further, the cylinder member 21 is restricted from further movement, that is, movement to the side opposite to the drive unit 23, when the tip 26 contacts the contact part 27 of the valve member 22.

  The valve member 22 has a vertical hole 34 and a horizontal hole 35. The vertical hole 34 is provided to extend in the axial direction inside the valve member 22. The vertical hole 34 has one end extending to the vicinity of the tip of the valve member 22, but does not penetrate the tip of the valve member 22. The horizontal hole 35 is connected to the end of the vertical hole 34 on the tip side, that is, the end opposite to the drive unit 23. The end of the horizontal hole 35 opposite to the vertical hole 34 opens in the outer wall 36 of the valve member 22. An end of the lateral hole 35 that opens to the outer wall 36 forms a nozzle hole 37. The vertical hole 34 is connected to the urea water pipe portion 17 on the side opposite to the end connected to the horizontal hole 35. As a result, the urea water supplied from the supply device 12 is supplied to the vertical hole 34 of the injection device 11 via the urea water pipe portion 17.

  As described above, the tubular member 21 is provided on the outer peripheral side of the valve member 22 fixed to the exhaust pipe portion 14, and is driven in the axial direction by the drive portion 23. Therefore, the tubular member 21 and the valve member 22 are relatively movable in the axial direction as shown in FIGS. The inner diameter of the cylindrical member 21 is set slightly larger than the outer diameter of the valve member 22. Thereby, the cylinder member 21 and the valve member 22 slide each other. As the cylindrical member 21 and the valve member 22 slide in this manner, the nozzle hole 37 opened in the outer wall 36 of the valve member 22 is opened and closed by the cylindrical member 21 moving on the outer peripheral side. That is, the nozzle hole 37 is closed by the cylindrical member 21 as shown in FIG. 2 when moving until the cylindrical member 21 contacts the contact portion 27. On the other hand, the nozzle hole 37 is opened as shown in FIGS. 1 and 3 when the cylindrical member 21 is moving toward the core 32 of the drive unit 23.

Next, the operation of the injection device 11 configured as described above will be described.
When the operation of the internal combustion engine is stopped, the control device 18 does not energize the urea water pump 16. Therefore, the supply of urea water from the supply device 12 to the injection device 11 is stopped. Further, the control device 18 does not energize the coil 31 of the injection device 11. Therefore, no magnetic field is generated from the coil 31, and no magnetic attractive force is generated between the core 32 and the cylindrical member 21. Thereby, the cylindrical member 21 moves to the exhaust passage 13 side by the pressing force of the elastic member 33, and the cylindrical member 26 contacts the contact portion 27. As a result, the nozzle hole 37 is closed by the cylindrical member 21 as shown in FIG.

  When the operation of the internal combustion engine is started, the control device 18 starts injection of urea water from the injection device 11. When it is time to inject the urea water, the control device 18 drives the urea water pump 16 and energizes the coil 31. By driving the urea water pump 16, the urea water stored in the urea water tank 15 is supplied to the injection device 11 via the urea water pipe portion 17. When the control device 18 energizes the coil 31, a magnetic field is generated from the coil 31, and a magnetic attractive force is generated between the core 32 and the cylindrical member 21. Thereby, the cylindrical member 21 moves toward the core 32 against the pressing force of the elastic member 33, and the cylindrical member 26 is separated from the contact portion 27. Further movement of the cylindrical member 21 is restricted when the flange portion 24 contacts the core 32. As the cylindrical member 21 moves to the core 32 side, the closing of the injection hole 37 by the cylindrical member 21 is released as shown in FIG. 3, and the injection hole 37 is exposed to the exhaust passage 13. The urea water supplied from the urea water pump 16 is supplied to the injection device 11 via the urea water pipe portion 17. Therefore, the supplied urea water is injected from the injection hole 37 to the exhaust passage 13 via the vertical hole 34 and the horizontal hole 35.

  Although most of the urea water supplied to the nozzle hole 37 is injected into the exhaust passage 13, a part of the urea water adheres to the outer wall 36 of the valve member 22 around the nozzle hole 37. Since the high-temperature exhaust gas discharged from the internal combustion engine flows through the exhaust passage 13, the moisture of the urea water attached to the outer wall 36 of the valve member 22 evaporates. Therefore, urea contained in the urea water precipitates as crystals 40 as shown in FIG. 3 and accumulates around the nozzle holes 37 on the outer wall 36 of the valve member 22. When urea water is continuously ejected from the nozzle hole 37, the nozzle hole 37 is not blocked by the deposited urea crystals 40. However, if the injection of urea water from the nozzle hole 37 is stopped, the grown urea crystal 40 may block the nozzle hole 37 and hinder the injection of urea water from the next time.

  In the case of the first embodiment, when stopping the injection of urea water, the control device 18 stops energizing the urea water pump 16 and stops energizing the coil 31. As a result, the magnetic attractive force between the core 32 and the cylindrical member 21 disappears, and the cylindrical member 21 moves until the cylindrical member 26 contacts the contact portion 27 by the pressing force of the elastic member 33 as shown in FIG. . At this time, since the tubular member 21 slides on the valve member 22, the urea crystals 40 deposited around the nozzle hole 37 are scraped off by the tubular member 21 that moves toward the tubular member 26. As a result, the urea crystal 40 deposited around the nozzle hole 37 is removed by the cylindrical member 21 every time the injection of urea water from the nozzle hole 37 is stopped.

  Further, when it is time to inject urea water again, the cylindrical member 21 moves to the core 32 side. After the urea water is injected from the injection device 11, a part of the urea water remaining in the vertical hole 34 and the horizontal hole 35 may enter a slight gap between the tubular member 21 and the valve member 22 and precipitate as crystals. . Thus, the crystal deposited between the tubular member 21 and the valve member 22 after the urea water injection is also destroyed when the tubular member 21 moves to the core 32 side when the urea water is injected. Therefore, the urea crystals deposited around the nozzle hole 37 are removed not only after the urea water injection but also before the urea water injection.

In the first embodiment described above, the cylindrical member 21 slides on the outer peripheral side of the valve member 22 in which the injection hole 37 opens in the outer wall 36. Therefore, even if urea crystals 40 derived from urea water adhering to the periphery of the nozzle hole 37 are deposited on the valve member 22, the accumulated urea crystals are still in the tubular member 21 when urea water is injected or stopped. Removed by moving. Therefore, clogging of the injection hole 37 accompanying urea deposition can be reduced, and reliable injection of urea water can be ensured.
Moreover, in 1st Embodiment, it has the drive part 23 which drives the cylinder member 21 by the electricity supply to the coil 31. FIG. Therefore, the movement of the cylinder member 21 is achieved without incurring a complicated structure. Therefore, clogging of the injection hole 37 can be reduced without increasing the number of parts and complicating the structure.

(Modification of the first embodiment)
A modification of the first embodiment is shown in FIG.
In the case of the modification, a stay 50 is provided in the exhaust pipe portion 14. The stay 50 is formed integrally or separately with the valve member 22 and is fixed to the exhaust pipe portion 14. In the stay 50, the end surface 51 on the drive unit 23 side contacts the end surface 52 on the exhaust passage 13 side of the flange portion 24 of the cylindrical member 21. On the other hand, the valve member 22 does not have a large diameter portion that forms a contact portion. Thus, even when the valve member 22 does not have a contact portion, the movement of the tubular member 21 toward the exhaust passage 13 is restricted by the flange portion 24 contacting the stay 50.

  In the case of the modification, the moving distance of the cylindrical member 21, that is, the stroke of the cylindrical member 21 is set by the length of the stay 50 in the axial direction. Therefore, even when a dimensional error occurs in the tubular member 21 and the valve member 22, the moving distance of the tubular member 21 is maintained constant by adjusting the length of the stay 50. This facilitates adjustment of the moving distance of the cylindrical member 21 and does not require high dimensional accuracy for the sliding cylindrical member 21 and valve member 22. Therefore, it is possible to easily process the parts and reduce the number of processing steps.

(Second Embodiment)
A urea water injection apparatus according to the second embodiment is shown in FIG.
In the case of the second embodiment, as shown in FIG. 6, the injection device 60 includes a cylindrical member 61, a valve member 62, and a drive unit 63. The cylindrical member 61 is formed in a cylindrical shape, and accommodates the valve member 62 in a slidable manner inside. The cylindrical member 61 is fixed through the exhaust pipe portion 14, and the tip projects into the exhaust passage 13.

  The valve member 62 is provided inside the cylindrical member 61 so as to be movable in the axial direction. Thus, the valve member 62 is provided so as to be movable in the radial direction of the exhaust pipe portion 14 through the exhaust pipe portion 14 on the inner peripheral side of the cylindrical member 61. The valve member 62 is provided coaxially with the cylindrical member 61, and the tip projects into the exhaust passage 13. The valve member 62 has a vertical hole 64 and a horizontal hole 65 as in the first embodiment. The vertical hole 64 extends in the axial direction inside the valve member 62 without penetrating the tip of the valve member 62. The horizontal hole 65 is provided so as to extend in the radial direction of the valve member 62 from the end portion on the distal end side of the vertical hole 64. An end of the horizontal hole 65 opposite to the vertical hole 64 forms an injection hole 67 in the outer wall 66 of the valve member 62. Further, the valve member 62 has a connection hole 68. The connection hole 68 connects the urea water pipe portion 17 and the vertical hole 64.

  The drive unit 63 includes a motor 71 and a transmission unit 72. The motor 71 is connected to the control device 18 and generates a driving force by energization from the control device 18. The transmission unit 72 includes a rack 73 and a pinion 74. The motor 71 drives the pinion 74 to rotate. The rack 73 is provided on a support portion 75 that extends to the opposite side of the valve member 62 from the exhaust passage 13. The support portion 75 is provided integrally with the valve member 62. The rotational motion of the motor 71 is converted into a linear motion of the valve member 62 in the transmission portion 72 constituted by the rack 73 and the pinion 74. By controlling the amount and direction of rotation of the motor 71 by the control device 18, the valve member 62 moves relative to the cylindrical member 61.

  As described above, the tubular member 61 accommodates the valve member 62 fixed to the exhaust pipe portion 14 and driven in the axial direction by the drive portion 63 on the inner peripheral side. Therefore, the cylinder member 61 and the valve member 62 are relatively movable in the axial direction. The inner diameter of the tubular member 61 is set slightly larger than the outer diameter of the valve member 62. Thereby, the cylinder member 61 and the valve member 62 slide on each other. As the cylindrical member 61 and the valve member 62 slide in this way, the nozzle hole 67 opened in the outer wall 66 of the valve member 62 is opened and closed by the cylindrical member 61 provided on the outer peripheral side. That is, the nozzle hole 67 is closed by the cylindrical member 61 when the valve member 62 moves upward in FIG. On the other hand, the nozzle hole 67 is opened when the cylindrical member 61 moves downward in FIG.

Next, the operation of the injection device 6 according to the second embodiment will be described.
When the operation of the internal combustion engine is stopped, the drive unit 63 drives the valve member 62 on the side opposite to the exhaust passage 13, that is, upward in FIG. Thereby, the valve member 62 is accommodated on the inner peripheral side of the cylindrical member 61 when the operation of the internal combustion engine is stopped and urea water is not injected. As a result, the nozzle hole 67 is closed by the cylindrical member 61.

When the operation of the internal combustion engine is started, the control device 18 starts injection of urea water from the injection device 60. When it is time to inject urea water, the control device 18 drives the urea water pump 16 and energizes the motor 71. By driving the urea water pump 16, the urea water stored in the urea water tank 15 is supplied to the injection device 60 via the urea water pipe portion 17. When the control device 18 energizes the motor 71, the motor 71 drives the valve member 62 to the exhaust passage 13 side, that is, downward in FIG. 6 via the transmission portion 72. Thereby, the valve member 62 moves to the exhaust passage 13 side by the driving force of the driving unit 63. As a result, the closing of the injection hole 67 by the cylindrical member 61 is released, the injection hole 67 is exposed to the exhaust passage 13, and the urea water supplied from the urea water pump 16 is injected from the injection hole 67 to the exhaust passage 13.
When it is time to stop the injection of urea water, the controller 18 drives the motor 71 again to drive the valve member 62 to the opposite side of the exhaust passage 13, that is, upward in FIG. As a result, the valve member 62 is again accommodated in the cylindrical member 61, and the injection hole 67 is closed by the cylindrical member 61. As a result, the injection of urea water from the nozzle hole 67 is stopped.

  In the second embodiment described above, the valve member 62 in which the injection hole 67 opens in the outer wall 66 slides on the inner peripheral side of the cylindrical member 61. Therefore, even if urea crystals derived from urea water adhering to the periphery of the nozzle hole 67 are deposited on the valve member 62, the accumulated urea crystals remain in the valve member 62 when the urea water is injected or stopped. Removed by movement. Therefore, clogging of the nozzle hole 67 due to urea precipitation can be reduced, and reliable injection of urea water can be ensured.

  In the second embodiment, the valve member 62 is driven by a drive unit 63 having a motor 71. Therefore, the driving force of the valve member 62 can be increased according to the output of the motor 71. Thus, for example, even when a large force is required to remove urea crystals deposited on the valve member 62, the urea crystals can be removed using the large driving force of the motor 71. Therefore, the reliable movement of the valve member 62 is achieved, the clogging of the injection hole 67 accompanying the precipitation of urea can be reduced, and the reliable injection of urea water can be ensured.

  Furthermore, in 2nd Embodiment, even if the energization to the motor 71 of the drive part 63 stops by driving the valve member 62 with the motor 71, the position of the valve member 62 is maintained. Therefore, it is not necessary to continue energization in order to maintain the position of the valve member 62 at the raised position or the lowered position. Therefore, power consumption can be reduced.

(Third embodiment)
A urea water injection device according to a third embodiment of the present invention is shown in FIG.
In 3rd Embodiment, as shown in FIG. 7, the injection apparatus 60 is equipped with the structure similar to 2nd Embodiment. In the case of the third embodiment, the valve member 62 of the injection device 60 has a first horizontal hole 81 and a second horizontal hole 82 that branch from the vertical hole 64. The first horizontal hole 81 extends radially outward from the tip end of the vertical hole 64 in the same manner as the horizontal hole of the second embodiment, and forms a main injection hole 83 in the outer wall 66 of the valve member 62. On the other hand, the second horizontal hole 82 penetrates the valve member 62 from the end portion on the front end side of the vertical hole 64 slightly toward the drive portion 63 side. The second lateral hole 82 forms a sub injection hole 84 in the outer wall 66 of the valve member 62.

  In the case of the third embodiment, only the main injection hole 83 or both the main injection hole 83 and the sub injection hole 84 of the valve member 62 of the injection device 60 is exposed to the exhaust passage 13 according to the amount of movement in the axial direction. That is, when the amount of movement of the valve member 62 in the axial direction is small, the cylinder member 61 opens only the main injection hole 83 and keeps the sub injection hole 84 closed. On the other hand, when the amount of movement of the valve member 62 in the axial direction increases, the cylindrical member 61 opens not only the main injection hole 83 but also the sub injection hole 84. Thereby, when the amount of movement of the valve member 62 in the axial direction is small, urea water is injected only from the main injection hole 83, and when the amount of movement of the valve member 62 in the axial direction becomes large, not only the main injection hole 83 but also the sub injection Urea water is also injected from the hole 84.

  The amount of urea water injected from the injection device 60 is controlled according to the operating state of the internal combustion engine. For example, when the load of the internal combustion engine is large and the flow rate of the exhaust gas is large, the injection amount of urea water increases compared to when the load is small and the flow rate of the exhaust gas is small. In the third embodiment, the amount of urea water injected is controlled by controlling the amount of movement of the valve member 62 in accordance with the operating state of the internal combustion engine. Therefore, an appropriate amount of urea water can be injected according to the operating state of the internal combustion engine.

As described above, the urea water injection device to which the plurality of embodiments are individually applied has been described. However, the plurality of embodiments may be combined and applied to the urea water injection device. For example, the configuration of the first embodiment or the second embodiment may be applied in combination with the third embodiment.
The present invention described above is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

Sectional drawing which shows the outline of the urea water injection system to which the injection apparatus by 1st Embodiment of this invention is applied. It is sectional drawing which shows the outline of the injection device by 1st Embodiment of this invention, and is a figure which shows the state which the cylinder member has closed the nozzle hole It is sectional drawing which shows the outline of the injection apparatus by 1st Embodiment of this invention, and is a figure which shows the state which the cylinder member has opened the nozzle hole It is sectional drawing which shows the outline of the injection apparatus by 1st Embodiment of this invention, and is a figure which shows the state which has removed the crystal | crystallization which the cylindrical member precipitated Sectional drawing which shows the outline of the injection apparatus by the modification of 1st Embodiment of this invention Sectional drawing which shows the outline of the injection apparatus by 2nd Embodiment of this invention Sectional drawing which shows the outline of the injection apparatus by 3rd Embodiment of this invention.

Explanation of symbols

  In the drawings, 11 and 60 are injection devices (urea water injection devices), 13 is an exhaust passage, 14 is an exhaust pipe portion, 21 and 61 are cylinder members, 22 and 62 are valve members, 23 and 63 are drive portions, and 25 is Large diameter portion, 26 is a tip, 27 is a contact portion, 34 and 64 are vertical holes, 35 and 65 are horizontal holes, 36 and 66 are outer walls, 37 and 67 are injection holes, 81 is a first horizontal hole, and 82 is a first hole. Two horizontal holes, 83 is a main injection hole, and 84 is a sub injection hole.

Claims (8)

A urea water injection device for injecting urea water into exhaust flowing through an exhaust passage of an internal combustion engine,
A tubular member having a tip projecting into the exhaust passage;
Provided on the inner peripheral side of the cylindrical member so as to be slidable in the axial direction with respect to the cylindrical member, and through the exhaust pipe portion forming the exhaust passage, the tip can protrude toward the exhaust passage side from the cylindrical member. A valve member;
Provided on the opposite side of the tubular member or the exhaust passage of the valve member, and provided with a drive unit for driving the tubular member and the valve member relatively in the axial direction;
The valve member has a longitudinal hole extending in the axial direction to the vicinity of the exhaust passage side tip on the inside, and an end portion of the longitudinal hole extending radially from the tip of the exhaust passage side on the opposite side to the longitudinal hole. A horizontal hole forming a nozzle hole opening in the
The urea water injection device according to claim 1, wherein the cylindrical member opens and closes the injection hole when the cylindrical member and the valve member relatively move in the axial direction.   The urea water injection device according to claim 1, wherein the valve member is fixed to the exhaust pipe portion, and the cylindrical member is provided so as to penetrate the exhaust pipe portion so as to be movable in an axial direction.   The urea water injection device according to claim 2, wherein the driving unit reciprocates the cylindrical member in the axial direction.   The urea water injection device according to claim 1, wherein the cylindrical member is fixed to the exhaust pipe portion, and the valve member is provided so as to penetrate the exhaust pipe portion so as to be movable in an axial direction.   The urea water injection device according to claim 4, wherein the drive unit reciprocates the valve member in the axial direction.   6. The urea water according to claim 1, wherein the valve member has a contact portion that can come into contact with a tip of the cylindrical member on the exhaust passage side at a tip of the exhaust passage. Injection device.   The urea water injection device according to claim 6, wherein the contact portion is provided in a large diameter portion having an outer diameter larger than that of the valve member.   The valve member branches from the vertical hole toward the distal end side on the exhaust passage side to form a main injection hole in the outer wall, and the drive from the vertical hole to the first horizontal hole is greater than the first horizontal hole. The urea water injection device according to any one of claims 1 to 7, further comprising a second horizontal hole that branches toward a portion side and forms a sub-injection hole in the outer wall.

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