JP2010090836A - Urea water supply equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide urea water supply equipment reducing the clogging of a jet hole due to the accumulation of deposits and reducing the jetting of urea water to improper directions by reducing the deposition of the deposits to an outlet side of the jet hole, and removing the deposits even when there is deposition of deposits. <P>SOLUTION: A water jetting nozzle 35 is provided facing a jetting nozzle 25 jetting out urea water. Then, the water jetted out from the water jetting nozzle 35 is sprayed on the outlet side of the jet hole 28 of the jetting nozzle 25. Thus, the urea water adhered to the outlet side of the jet hole 28 is washed by the sprayed water. Deposition and accumulated deposits on the outlet side of the jet hole 28 is dissolved no only by the sprayed water, but destroyed by the physical energy of the sprayed water. As a result, the deposition of deposits on the outlet side of the jet hole 28 is reduced, and the deposits are removed even when there is deposition of deposits. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a urea water supply device that supplies urea water to 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 water or nitrogen by, for example, injecting urea or ammonia as a reducing agent. Urea contained in the urea water generates precipitates that are soluble or insoluble in water due to evaporation of moisture or chemical changes due to heat of exhaust gas. The deposit accumulates on the exhaust pipe portion forming the exhaust passage, the urea water injection nozzle, and the like, causing a malfunction. Therefore, in Patent Document 1, water for cleaning is supplied to a urea water path for supplying urea water, and the deposits deposited in the urea water path are removed.

However, the deposit accumulates not only in the urea water path but also in the injection hole of the urea water injection nozzle that injects the urea water, particularly on the outlet side of the injection hole. Therefore, even if water is supplied to the urea water path, it is difficult to remove the deposits deposited on the outlet side of the nozzle hole. Thus, when deposits accumulate on the outlet side of the nozzle hole, there is a problem that the nozzle hole is blocked or the injection direction of urea water from the nozzle hole is changed to an inappropriate direction.
JP 2005-248924 A

  Accordingly, an object of the present invention is to reduce the precipitation of precipitates on the outlet side of the nozzle hole, and even if the deposits are deposited, the precipitates are removed, and the nozzle holes are clogged and not deposited due to the deposition of the deposits. An object of the present invention is to provide a urea water supply device that reduces injection of urea water in an appropriate direction.

  In invention of Claim 1, the water injection part which injects water toward a nozzle hole is provided. Therefore, the water jetted from the water jetting unit is sprayed to the outlet side of the nozzle hole. Therefore, the deposit deposited on the outlet side of the nozzle hole is destroyed or removed by the physical energy of water. Further, for example, by injecting water from the water injection unit after the injection of urea water from the injection hole is completed, the outlet side of the injection hole is washed with water. Therefore, the deposit on the outlet side of the nozzle hole is reduced. Therefore, the deposit on the outlet side of the nozzle hole can be reduced, and even if the deposit is deposited, the deposit can be removed. Thereby, the clogging of the nozzle hole due to the deposition of precipitates and the injection of urea water in an inappropriate direction can be reduced.

In the invention according to claim 2, the water supply part which changes the pressure of water and supplies it to a water injection part is provided. Thereby, the pressure of the water injected from a water injection part changes. Therefore, for example, the pressure of the water to be sprayed can be changed according to the state of precipitates deposited on the outlet side of the nozzle hole.
In the invention according to claim 3, when the urea water injection from the urea water injection nozzle is completed, the water injection unit injects water. Therefore, the urea water adhering to the outlet side of the nozzle hole after the urea water injection is removed by the water injected from the water injection unit. Therefore, deposit accumulation on the outlet side of the nozzle hole can be reduced.

  In the invention according to claim 4, the water supply unit increases the pressure of the supplied water as the temperature of the exhaust gas flowing through the exhaust passage increases. The temperature of the exhaust flowing through the exhaust passage varies depending on the load of the internal combustion engine. For example, when the load on the internal combustion engine is large, the amount of fuel supplied to the internal combustion engine increases, and the combustion temperature of the air-fuel mixture in each combustion chamber also rises. Therefore, the temperature of the exhaust gas increases as the load on the internal combustion engine increases. On the other hand, when the temperature of the exhaust gas rises, the amount of NOx produced increases, so the urea water injection amount also increases. Thus, when the injection amount of urea water increases, urea water adhering to the outlet side of the nozzle hole and deposits that precipitate are also increased. Therefore, by spraying high-pressure water toward the nozzle hole, cleaning of urea water with an increased amount of adhesion and removal of precipitates with an increased amount of precipitation are promoted. Therefore, according to the operation of the internal combustion engine, cleaning of the outlet side of the nozzle hole and removal of the deposit can be achieved.

In invention of Claim 5, water is injected from the water injection part provided facing the nozzle hole. Thereby, the water jetted from the water jetting unit is easily and reliably sprayed onto the nozzle hole. Therefore, it is possible to remove the deposit that has been washed and deposited on the outlet side of the nozzle hole.
In invention of Claim 6, water is injected from the water injection part provided in the radial direction outer side of the nozzle hole. Thereby, the water jetted from the water jetting unit is easily and reliably sprayed onto the nozzle hole. Further, the nozzle hole and the water injection unit are arranged close to each other. Therefore, it is possible to remove the deposit that has been washed and deposited on the outlet side of the nozzle hole.

Hereinafter, a plurality of embodiments of a urea water supply 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 gas purification system to which a urea water supply device (hereinafter referred to as “supply device”) according to a first embodiment of the present invention is applied. The exhaust purification system 10 includes a supply device 11. The exhaust purification system 10 reduces NOx contained in exhaust flowing through an exhaust pipe portion 13 of an internal combustion engine (not shown) using urea water supplied to the exhaust from the supply 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 13 has one end connected to an internal combustion engine (not shown). Further, the end of the exhaust pipe 13 opposite to the internal combustion engine is open to the atmosphere. The exhaust pipe portion 13 has a cylindrical shape and forms an exhaust passage 14 for discharging the exhaust gas of the internal combustion engine to the atmosphere. The exhaust purification system 10 includes an SCR catalyst (not shown) on the downstream side of the supply device 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) (not shown).

  The supply device 11 includes a urea water injection unit 15 and a water injection unit 16. The urea water injection unit 15 includes a urea water tank 21, a urea water pump 22, an on-off valve 23, a urea water pipe unit 24, and a urea water injection nozzle (hereinafter referred to as “injection nozzle”) 25. The urea water tank 21 stores urea water, that is, an aqueous solution of urea. The urea water pump 22 supplies urea water stored in the urea water tank 21 to the injection nozzle 25. The on-off valve 23 intermittently supplies urea water from the urea water pump 22 to the injection nozzle 25. The urea water pipe portion 24 forms a urea water passage 26 that connects the urea water tank 21 and the injection nozzle 25.

  The urea water pipe portion 24 penetrates the exhaust pipe portion 13 that forms the exhaust passage 14. As shown in FIG. 2, the injection nozzle 25 is connected to the end of the urea water pipe portion 24 on the exhaust passage 14 side. The injection nozzle 25 has a nozzle passage 27 connected to the urea water passage 26 on the inside and an injection hole 28 for injecting urea water at the tip. The nozzle hole 28 is located at the tip of the nozzle passage 27 and is exposed to the exhaust passage 14. The injection nozzle 25 is provided downstream of an internal combustion engine (not shown) in the exhaust flow direction in the exhaust passage 14 and upstream of an SCR catalyst (not shown). The injection nozzle 25 injects urea water into the exhaust flowing through the exhaust passage 14. Thereby, the urea water injected from the injection nozzle 25 is mixed with the exhaust gas and flows into an SCR catalyst (not shown). In the case of this embodiment, the injection nozzle 25 extends in the axial direction of the exhaust pipe part 13 from the end of the urea water pipe part 24 penetrating the exhaust pipe part 13 in the radial direction toward the SCR catalyst side. Thereby, the urea water is injected toward the downstream side, that is, the SCR catalyst along the flow of the exhaust gas from the injection nozzle 25.

  As shown in FIG. 1, the water injection unit 16 includes a water tank 31, a water pump 32, an on-off valve 33, a water pipe unit 34, and a water injection nozzle 35. The water tank 31 stores water. The water pump 32 supplies water stored in the water tank 31 to the water injection nozzle 35. The on-off valve 33 intermittently supplies water from the water pump 32 to the water injection nozzle 35. The water pipe portion 34 forms a water passage 36 that connects between the water tank 31 and the water injection nozzle 35. The water tank 31, the water pump 32, the on-off valve 33, and the water pipe part 34 constitute the water supply part in the claims.

  The water pipe portion 34 penetrates the exhaust pipe portion 13 that forms the exhaust passage 14. As shown in FIG. 2, the water injection nozzle 35 is connected to the end of the water pipe portion 34 on the exhaust passage 14 side. The water injection nozzle 35 forms a water nozzle passage 37 connected to the water passage 36 on the inner side and a jet outlet 38 for jetting water at the tip. The spout 38 is located at the tip of the water nozzle passage 37 and is exposed to the exhaust passage 14. The water injection nozzle 35 is provided in the vicinity of the injection nozzle 25 of the supply device 11. The water injection nozzle 35 injects water toward the injection hole 28 of the injection nozzle 25. Thereby, the water sprayed from the water spray nozzle 35 is sprayed around the nozzle hole 28 of the spray nozzle 25. In the case of this embodiment, the water pipe part 34 connected to the water injection nozzle 35 is provided substantially in parallel with the urea water pipe part 24 connected to the injection nozzle 25. The water injection nozzle 35 is inclined and connected to the injection nozzle 25 side from the end of the water pipe portion 34 so that the injection port 38 faces the injection hole 28.

  The exhaust purification system 10 includes a control device 40 such as an ECU (Electronic Control Unit). The control device 40 has a microcomputer composed of a CPU, ROM and RAM (not shown). The control device 40 is connected to, for example, an accelerator opening sensor 41, a rotation speed sensor 42, and the like. The control device 40 sets a fuel injection amount from an injector (not shown) based on signals output from the accelerator opening sensor 41 and the rotation speed sensor 42, and detects an operating state of an internal combustion engine (not shown). . Further, the control device 40 is connected to a temperature sensor 43 that is an exhaust gas temperature detecting means. The temperature sensor 43 is provided in the exhaust passage 14 and detects the temperature of the exhaust gas flowing through the exhaust passage 14. Based on the operating state of the internal combustion engine detected by the accelerator opening sensor 41 and the rotation speed sensor 42 and the temperature of the exhaust gas flowing through the exhaust passage 14, the control device 40 controls the urea water pump 22, the on-off valve 23, and the water pump 32. And controls the on-off valve 33 and the like. As a result, the control device 40 controls the pressure of the urea water injected from the injection nozzle 25 and the injection timing, and the pressure of the water injected from the water injection nozzle 35 and the injection timing.

The operation of the supply device 11 having the above configuration will be described with reference to FIG.
When the operation of an internal combustion engine (not shown) is started and it is time to inject urea water, the control device 40 performs injection of urea water. At this time, the control device 40 is based on the accelerator pedal depression amount detected by the accelerator opening sensor 41, the rotational speed of the internal combustion engine detected by the rotational speed sensor 42, the exhaust temperature detected by the temperature sensor 43, and the like. It is determined whether to inject urea water. As a result, when injecting urea water, the control device 40 drives the urea water pump 22 to pressurize the urea water stored in the urea water tank 21 and opens the urea water pipe section 24 by the opening / closing valve 23. Urea water is supplied to the injection nozzle 25. Thereby, the urea water supplied from the urea water tank 21 is injected toward the exhaust gas flowing through the exhaust passage 14 from the injection hole 28 of the injection nozzle 25.

  The control device 40 switches the injection pressure of urea water to a low pressure or a high pressure based on the operating state of the internal combustion engine detected by the accelerator opening sensor 41 or the rotation speed sensor 42. For example, when the internal combustion engine is operated with a large load, the flow rate of the exhaust gas increases and the pressure of the exhaust gas increases. Therefore, the control device 40 injects higher-pressure urea water when the load of the internal combustion engine is larger than a predetermined value. The control device 40 changes the amount of urea water pressurized by the urea water pump 22 to control the pressure of the urea water injected from the injection nozzle 25. When urea water is being injected from the injection nozzle 25, the control device 40 stops driving the water pump 32 and closes the water pipe portion 34 by the opening / closing valve 33. Therefore, while urea water is being injected from the injection nozzle 25, water is not injected from the water injection nozzle 35.

  When the urea water injection from the injection nozzle 25 stops with the stop of the operation of the internal combustion engine (not shown), the control device 40 injects water from the water injection nozzle 35. At this time, as shown in FIG. 3, the control device 40 intermittently injects water from the water injection nozzle 35 in a plurality of times. The jet port 38 of the water jet nozzle 35 faces the nozzle hole 28 of the jet nozzle 25. Therefore, the water ejected from the ejection port 38 of the water ejection nozzle 35 is sprayed toward the ejection hole 28 of the ejection nozzle 25.

  A part of the urea water ejected from the nozzle hole 28 is attached around the nozzle hole 28 of the nozzle 25, that is, on the outlet side of the nozzle hole 28. Since the exhaust gas from the internal combustion engine flows through the exhaust passage 14, the exhaust passage 14 has a high temperature of about several hundred degrees Celsius depending on the operating state of the internal combustion engine. When the urea water adhering to the outlet side of the nozzle hole 28 is exposed to such high-temperature exhaust gas, moisture is evaporated or a chemical change occurs. As a result, a precipitate 29 derived from urea contained in the urea water is deposited on the outlet side of the nozzle hole 28. Since the deposited precipitate 29 grows with time, the deposited material 29 is deposited on the outlet side of the nozzle hole 28 as shown in FIG. By spraying water from the water injection nozzle 35 toward the nozzle hole 28, the urea water adhering to the outlet side of the nozzle hole 28 is washed away, and the deposit 29 deposited on the outlet side of the nozzle hole 28 is removed. The deposit 29 deposited and deposited on the outlet side of the nozzle hole 28 contains a component soluble in water and a component insoluble or hardly soluble in water. By jetting water from the water jet nozzle 35, the precipitate 29 made of a water-soluble component is dissolved in water and removed from the outlet side of the nozzle hole 28. On the other hand, the precipitate 29 composed of a component that is insoluble or hardly soluble in water is destroyed by the physical energy of the water jetted from the water jet nozzle 35. As a result, the precipitate 29 made of a component insoluble or hardly soluble in water is also removed from the outlet side of the nozzle hole 28.

  In this way, when the precipitate 29 composed of a component that is insoluble or hardly soluble in water is destroyed by the water jetted from the water jet nozzle 35, the physical energy of the water is proportional to the pressure of the water. That is, the destructive force increases as the pressure of water to be injected increases. For this reason, the pressure of water sprayed from the water spray nozzle 35 is preferably as high as possible. However, since the amount of water required for injection is also proportional to the water pressure, increasing the water pressure increases the total amount of water required, leading to an increase in the size of the water tank 31 that stores water. Therefore, by intermittently injecting water from the water injection nozzle 35, the total amount of water to be injected can be reduced while ensuring the pressure of the water to be injected, that is, maintaining the destructive force.

  Further, the control device 40 controls the pressure of water ejected from the water ejection nozzle 35, that is, the amount of water pressurized by the water pump 32. As described above, the deposit 29 deposited on the outlet side of the injection hole 28 of the injection nozzle 25 is accelerated to break down as the energy of the water to be injected increases. On the other hand, the amount of the deposit 29 deposited on the outlet side of the injection hole 28 of the injection nozzle 25 varies depending on the operating state of the internal combustion engine. For example, when the internal combustion engine is operated with a large load, the combustion temperature rises and the amount of NOx contained in the exhaust increases. Therefore, the amount of urea water injected from the injection nozzle 25 also increases according to the amount of NOx to be reduced, and the amount of urea water attached to the outlet side of the injection hole 28 of the injection nozzle 25 also increases. Further, when the amount of urea water injected from the injection nozzle 25 increases, the temperature of the exhaust gas increases as the combustion temperature increases, so that the urea water adhering to the outlet side of the injection hole 28 of the injection nozzle 25 is exhausted. Water evaporation and chemical changes due to heat are promoted. As a result, when the load during operation of the internal combustion engine is large, the precipitate 29 tends to be deposited on the outlet side of the injection hole 28 of the injection nozzle 25. On the other hand, when the load during operation of the internal combustion engine is small, the temperature of the exhaust gas also decreases compared to when the load is large, and the deposit 29 deposited on the outlet side of the injection hole 28 of the injection nozzle 25 decreases. As described above, the deposit 29 deposited on the outlet side of the injection hole 28 of the injection nozzle 25 correlates with the load during operation of the internal combustion engine, that is, the temperature of the exhaust gas flowing through the exhaust passage 14.

  Therefore, the control device 40 determines the injection nozzle 25 based on the operating state of the internal combustion engine detected by the accelerator opening sensor 41 and the rotational speed sensor 42 and the temperature of the exhaust gas during operation of the internal combustion engine detected by the temperature sensor 43. While calculating the quantity of urea water injected from the nozzle hole 28, the quantity of the deposit 29 deposited on the exit side of the nozzle hole 28 is estimated. And when it is thought that the precipitation amount of the deposit | precipitate 29 estimated is larger than arbitrary predetermined values, the control apparatus 40 pressurizes water to the high pressure by the water pump 32. FIG. Thereby, relatively high pressure water is jetted from the water jet nozzle 35 toward the nozzle hole 28 of the jet nozzle 25. On the other hand, when the estimated precipitation amount of the precipitate 29 is considered to be smaller than an arbitrary predetermined value, the control device 40 pressurizes the water to a lower pressure by the water pump 32. As a result, relatively low pressure water is jetted from the water jet nozzle 35 toward the nozzle hole 28 of the jet nozzle 25. Note that the pressure of the urea water and the pressure of the water are not limited to two stages of high pressure and low pressure as illustrated, and may be switched to three or more stages.

  As described above, in the first embodiment of the present invention, the water jetted from the water jet nozzle 35 is sprayed to the outlet side of the nozzle hole 28 of the jet nozzle 25. Therefore, the deposit 29 deposited and deposited on the outlet side of the nozzle hole 28 is not only dissolved in water but also destroyed by the physical energy of water. That is, after the injection of urea water from the injection hole 28 of the injection nozzle 25 is completed, the urea water attached to the outlet side of the injection hole 28 is washed by injecting water from the water injection nozzle 35 toward the injection hole 28. Then, the deposit 29 deposited on the outlet side of the nozzle hole 28 is removed. Thereby, deposition of the precipitate 29 on the outlet side of the nozzle hole 28 is reduced. Therefore, precipitation of the precipitate 29 on the outlet side of the nozzle hole 28 can be reduced, and even if the precipitate 29 is deposited, the precipitate 29 can be removed. Further, by removing the precipitate 29 around the nozzle hole 28, it is possible to reduce clogging of the nozzle hole 28 due to the deposit 29 and the injection of urea water in an unexpected and inappropriate direction.

  Moreover, in 1st Embodiment, the pressure of the water injected from the water injection nozzle 35 changes based on the driving | running state of an internal combustion engine, etc. Therefore, for example, when the load during operation of the internal combustion engine is large and a large amount of deposits 29 are likely to be deposited on the outlet side of the nozzle hole 28, high-pressure water is generated compared to when the load during operation of the internal combustion engine is small. Be injected. Specifically, the pressure of the supplied water is increased as the temperature of the exhaust gas flowing through the exhaust passage 14 increases. The temperature of the exhaust gas flowing through the exhaust passage 14 varies depending on the load of the internal combustion engine. Further, when the temperature of the exhaust gas rises, the amount of NOx produced increases, so the urea water injection amount also increases. Thus, when the injection amount of urea water increases, the urea water adhering to the outlet side of the nozzle hole 28 and the deposit 29 that precipitates also increase. Therefore, by spraying high-pressure water toward the nozzle hole 28, cleaning of urea water with an increased adhesion amount and removal of the precipitate 29 with an increased precipitation amount are promoted. Therefore, according to the operation of the internal combustion engine, it is possible to clean the outlet side of the nozzle hole 28 and remove the precipitate 29.

  Furthermore, in the first embodiment, water is jetted from a water jet nozzle 35 provided to face the nozzle hole 28. Thereby, the water sprayed from the water spray nozzle 35 is sprayed to the nozzle hole 28 easily and reliably. Therefore, it is possible to remove the precipitate 29 that has been washed and deposited on the outlet side of the nozzle hole 28.

(Second Embodiment)
The principal part of the exhaust gas purification system according to the second embodiment of the present invention is shown in FIG.
In 2nd Embodiment, as shown in FIG. 4, as for the supply apparatus 11, the urea water pipe part 24 of the urea water injection part 15 and the water pipe part 34 of the water injection part 16 are arrange | positioned coaxially. That is, the water pipe part 34 is provided on the outer peripheral side of the urea water pipe part 24 that forms the urea water path 26, and the water path 36 is formed between the urea water pipe part 24 and the water pipe part 34. The urea water pipe portion 24 and the water pipe portion 34 arranged on the same axis are a vertical pipe portion 51 that penetrates the exhaust pipe portion 13 in the radial direction, and a downstream side in the exhaust flow direction from the radially inner end of the vertical pipe portion 51. It is comprised from the side pipe part 52 extended in the axial direction of the exhaust pipe part 13 to the side. A space between the urea water pipe portion 24 and the water pipe portion 34 is supported by a support portion 53.

  A nozzle cap 60 is provided at the ends of the urea water pipe part 24 and the horizontal pipe part 52 of the water pipe part 34. As shown in FIG. 5, the nozzle cap 60 has an injection nozzle 61 as a urea water injection nozzle connected to the urea water passage 26 at the center in the radial direction. The tip of the injection nozzle 61 is an injection hole 62 that is exposed to the exhaust passage 14 and injects urea water. The nozzle cap 60 has a water injection nozzle 63 connected to the water passage 36 on the radially outer side of the injection nozzle 61. The water jet nozzle 63 is inclined with respect to the jet nozzle 61 and forms a jet port 64 at the tip thereof. The jet port 64 is formed on the radially outer side of the nozzle hole 62. In the case of 2nd Embodiment, the water injection nozzle 63 comprises the water injection part of a claim.

  In the present embodiment, four jet ports 64 are provided on the radially outer side of the nozzle holes 62. As shown in FIG. 5, in the cross section including the central axis C1 of the injection nozzle 61, the virtual axis C1 that is parallel to the central axis C1 of the injection nozzle 61 and intersects with the central axis of the water injection nozzle 63 at the outlet 64. Is arranged so as to be shifted in the radial direction of the nozzle cap 60. From the nozzle hole 62, urea water is injected in an angle α range with respect to the central axis C1 of the injection nozzle 61 including the nozzle hole 62. On the other hand, by displacing the central axis C1 of the nozzle hole 62 and the virtual straight line C2 of the nozzle 64, the injection angle of urea water from the nozzle 64 (the nozzle 64 below the nozzle 62 in FIG. 5). Water is jetted at a water jet angle θ = α + β obtained by adding an angle β to α. Here, the angle β corresponds to the inclination angle of the water injection nozzle 63 with respect to the injection nozzle 61. Thereby, the urea water and the precipitate 29 adhering to the outlet side of the nozzle hole 62 are reliably removed by the water jetted from the nozzle 64.

  As shown in FIG. 6, the central axis C <b> 3 of the water injection nozzle 63 is provided in the tangential direction of the injection hole 62 formed at the tip of the injection nozzle 61. That is, the water jet nozzle 63 that forms the jet port 64 is offset to the position of the angle γ with respect to the jet nozzle 61 that forms the nozzle hole 62. Thereby, water is jetted in a swirling manner around the central axis C <b> 1 of the jet nozzle 61 from the jet port 64 formed at the tip of each water jet nozzle 63. As a result, the water jetted from each jet port 64 is sprayed to the outlet side of the nozzle hole 62 without interfering with each other.

  In 2nd Embodiment, the jet nozzle 64 which injects water to the radial direction outer side of the nozzle hole 62 is arrange | positioned. Therefore, the water jetted from the jet port 64 is reliably blown toward the outlet side of the nozzle hole 62. Further, with this configuration, the nozzle hole 62 and the jet port 64 are arranged close to each other. Therefore, the water jetted from the jet port 64 is more reliably sprayed to the outlet side of the nozzle hole 62. Therefore, it is possible to reduce the adhesion of urea water to the outlet side of the nozzle hole 62 and the deposition of the precipitate 29 derived from the urea water, clogging of the nozzle hole 62, and urea water in an unexpected direction. Injection can be reliably reduced.

  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.

The schematic diagram which shows the exhaust gas purification system to which the urea water supply apparatus by 1st Embodiment of this invention is applied. The schematic diagram which shows the cross section of the principal part of the urea water supply apparatus by 1st Embodiment of this invention. Schematic which shows the operation timing of the urea water supply apparatus by 1st Embodiment of this invention. The schematic diagram which shows the cross section of the principal part of the urea water supply apparatus by 2nd Embodiment of this invention. The figure which expanded the nozzle cap vicinity of FIG. Viewed from the direction of arrow VI in FIG.

Explanation of symbols

  In the drawing, 11 is a supply device (urea water supply device), 14 is an exhaust passage, 16 is a water injection unit, 25 is an injection nozzle (urea water injection nozzle), 28 is an injection hole, and 31 is a water tank (water supply unit). 32 is a water pump (water supply part), 33 is an on-off valve (water supply part), 34 is a water pipe part (water supply part), 61 is an injection nozzle (urea water injection nozzle), 62 is an injection hole, and 63 is water. An injection nozzle (water injection part) is shown.

Claims (6)

A urea water supply device for supplying urea water to exhaust gas flowing through an exhaust passage of an internal combustion engine,
A urea water injection nozzle having a nozzle hole for injecting urea water at a tip exposed in the exhaust passage;
A water injection unit for injecting water toward the nozzle hole;
A urea water supply device comprising:   The urea water supply apparatus according to claim 1, further comprising a water supply unit configured to supply water with variable pressure to the water injection unit.   3. The urea water supply apparatus according to claim 1, wherein the water injection unit injects water when the urea water injection from the urea water injection nozzle ends. 4.   The urea water supply apparatus according to claim 2, wherein the water supply unit increases the pressure of the supplied water as the temperature of the exhaust gas flowing through the exhaust passage increases.   The urea water supply apparatus according to any one of claims 1 to 4, wherein the water injection unit is provided to face the injection hole.   The urea water supply device according to any one of claims 1 to 4, wherein the water injection unit is provided on the radially outer side of the injection hole.

Images