JP2010019197A - Exhaust emission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device in which the improper supply of an additive into an exhaust gas passage caused by a deposit accumulated on an edge surface of an injector is prevented. <P>SOLUTION: The injector for injecting the additive into the exhaust gas passage 12 communicating with an engine 11 is fixed in a communication passage 61 communicating with the exhaust gas passage 12 in a state of exposing the edge surface 52 where its nozzle 51 is opened. The communication passage 61 is formed to be arranged with a scratching means 80 for scratching and removing the deposit accumulated on the edge surface 52 of the injector 50 by a sliding member 81 which slides on the edge surface 52 of the injector 50. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an exhaust purification device that purifies exhaust gas discharged from an engine.

  In exhaust gas exhausted from engines mounted on automobiles, especially diesel engines, carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and particulate matter (PM) ) Etc. are included. For this reason, in general, for example, a three-way catalyst for decomposing (reducing, etc.) the pollutants and a particulate filter for capturing PM in an exhaust passage through which exhaust gas discharged from the engine passes. Etc., so that the exhaust gas is discharged into the atmosphere as harmless as possible.

  In such a particulate filter, since PM accumulates in the filter and the passage resistance increases with use, it is necessary to perform a regeneration process as necessary. As such regeneration processing, a heating device is provided in the particulate filter, and PM is burned and removed by heating. However, fuel (light oil) is added to the oxidation catalyst provided upstream of the particulate filter. A method is also proposed in which a hydrocarbon-based liquid such as) is introduced to cause an exothermic reaction and the particulate filter is regenerated by this heat.

  In diesel engines, nitrogen oxides (NOx) are particularly likely to be generated. For this reason, in order to efficiently decompose NOx in exhaust gas, many so-called NOx trap catalysts that decompose and reduce NOx by repeatedly adsorbing and reducing NOx, for example, are often used in diesel engines. ing.

  Since such NOx trap catalyst decomposes (reduces) adsorbed NOx, it is necessary to appropriately supply a reducing agent (additive) from the outside to the NOx trap catalyst. For this reason, in general, fuel (light oil) or the like is supplied as a reducing agent into the exhaust passage so as to be supplied to the NOx trap catalyst. For example, there is one in which fuel is injected into an exhaust passage by an injector provided in an exhaust pipe, and exhaust gas mixed with the fuel is supplied to a NOx trap catalyst (see, for example, Patent Document 1).

  Since NOx trap catalyst also adsorbs sulfur oxide (SOx) together with NOx, fuel (reducing agent) is supplied to the NOx trap catalyst to raise the temperature of the NOx trap catalyst, thereby decomposing (reducing) SOx. Things are also done.

JP-A-2005-214100

  There is a possibility that so-called deposits gradually accumulate on the tip surface of the injector and the periphery thereof, and problems such as nozzle clogging may occur.

  Specifically, the tip surface of the injector nozzle that injects a reducing agent such as fuel into the exhaust passage is exposed in the exhaust passage and exposed to high-temperature exhaust gas. It becomes relatively hot. For this reason, when the reducing agent (for example, fuel) injected from the injector adheres to the tip end surface of the injector, the volatile component of the attached reducing agent evaporates and the remaining component is denatured and gradually accumulates as deposit. Further, the adhering reducing agent becomes a binder, soot in the exhaust gas adheres and gradually accumulates as a deposit.

  If deposits accumulate on the tip surface of the injection in this way, the nozzles of the injector may become clogged, and the reducing agent may not be supplied satisfactorily to the exhaust passage. Further, deposits accumulate on the wall surface of the communication passage, and the passage of the reducing agent injected from the nozzle is narrowed. Similarly, there is a possibility that the reducing agent cannot be supplied satisfactorily to the exhaust passage.

  When deposits are deposited on the injector or the like in this way, it is necessary to perform maintenance work for removing the deposited deposits by removing the injectors. To remove the injector, it is necessary to remove the mounting member to which the injector is attached, the reducing agent (fuel) pipe attached to the injector, the cooling water pipe around it, etc. Work requires considerable effort.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an exhaust purification device that prevents poor supply of additives into the exhaust passage due to deposits deposited on the tip surface of an injector.

  A first aspect of the present invention that solves the above problems is an exhaust purification catalyst that is interposed in an exhaust passage communicating with an engine, and is provided upstream of the exhaust purification catalyst and added to the exhaust passage. An injector for injecting the agent, and the injector is fixed in an exposed state in a communicating path connected to the exhaust passage, and the leading end surface of the injector slides in the communicating path. In the exhaust emission control device, scraping means for scraping the deposit accumulated on the tip surface of the injector by a sliding member is provided.

  In the first aspect, even if deposits are accumulated on the tip surface of the injector, the deposits are scraped off at a predetermined timing by the sliding member of the scraping means. Therefore, it is possible to prevent occurrence of problems such as clogging of the nozzle of the injector or narrowing of the communication path, and it is possible to always supply the additive into the exhaust path satisfactorily.

  According to a second aspect of the present invention, in the exhaust emission control device according to the first aspect, the sliding member also functions as a part of a peripheral wall of the communication path.

  In this second aspect, the sliding member of the scraping means itself does not narrow the communication path which is the flow path of the additive, and the additive is satisfactorily supplied into the exhaust passage through the communication path.

  In a third aspect of the present invention, the sliding member is made of a plate-shaped shape memory alloy that is disposed along the circumferential direction of the communication path and has one end fixed to the peripheral wall of the communication path. In the exhaust emission control device of the first or second aspect.

  In the third aspect, since the deposit can be scraped off by utilizing the deformation of the sliding member itself, the structure of the scraping means can be simplified.

  In a fourth aspect of the present invention, the scraping means includes the sliding member and a moving means for moving the sliding member, and the moving means moves the sliding member to the communication path. A first biasing member comprising a spring member biasing toward the center, and a second biasing member capable of biasing the sliding member against a biasing force by the spring member under a predetermined condition; The exhaust emission control device according to the first or second aspect is characterized by comprising:

  In the fourth aspect, the sliding member can be reliably slid with respect to the tip surface of the injector by the moving means having a relatively simple structure.

  According to a fifth aspect of the present invention, in the exhaust emission control device according to the fourth aspect, the second urging member is made of a shape memory alloy storing a shape in a contracted state.

  In the fifth aspect, the sliding member can be reliably slid relative to the tip surface of the injector by the moving means having a relatively simple structure.

  According to a sixth aspect of the present invention, the exhaust gas purification according to the fourth aspect, wherein the second biasing member is an air actuator that biases the sliding member by setting the inside to a negative pressure. In the device.

  In the sixth aspect, the sliding member can be reliably slid with respect to the tip surface of the injector by the moving means having a relatively simple structure.

  According to a seventh aspect of the present invention, in the exhaust emission control device according to any one of the first to sixth aspects, the sliding member is provided at least downstream of the exhaust passage of the communication passage. is there.

  In the seventh aspect, since the sliding member is provided on the downstream side of the exhaust pipe passage of the communication passage where deposits are likely to accumulate, the sliding member itself and deposits around the sliding member are dropped by the movement of the sliding member. be able to.

  In the present invention, since the deposit accumulated on the tip end surface of the injector is scraped off by the scraping means, the additive can be satisfactorily supplied to the exhaust passage. In addition, there is no need to perform maintenance work for disassembling the apparatus and removing deposits deposited on the tip surface of the injector.

  Hereinafter, embodiments of the present invention will be described in detail.

(Embodiment 1)
FIG. 1 is a diagram showing a schematic configuration of an exhaust emission control device according to the present embodiment. As shown in FIG. 1, the exhaust purification device 10 has a plurality of exhaust purification catalysts and exhaust purification filters, and the plurality of exhaust purification catalysts and exhaust purification filters are installed in a vehicle. An exhaust pipe (exhaust passage) 12 of a cylinder diesel engine (hereinafter simply referred to as an engine) 11 is interposed.

  The engine 11 includes a cylinder head 13 and a cylinder block 14, and a piston 16 is accommodated in each cylinder bore 15 of the cylinder block 14 so as to be reciprocally movable. A combustion chamber 17 is formed by the piston 16, the cylinder bore 15, and the cylinder head 13. The piston 16 is connected to a crankshaft 19 via a connecting rod 18 so that the crankshaft 19 is rotated by the reciprocating motion of the piston 16.

  An intake port 20 is formed in the cylinder head 13, and an intake pipe (intake passage) 22 including an intake manifold 21 is connected to the intake port 20. The intake port 20 is provided with an intake valve 23, and the intake port 20 is opened and closed by the intake valve 23. An exhaust port 24 is formed in the cylinder head 13, and an exhaust pipe (exhaust passage) 12 including an exhaust manifold 25 is connected to the exhaust port 24. The exhaust port 24 is provided with an exhaust valve 26. Like the intake port 20, the exhaust port 24 is opened and closed by the exhaust valve 26. A turbocharger 27 is provided in the middle of the intake pipe 22 and the exhaust pipe 12, and an exhaust purification catalyst and an exhaust purification catalyst that constitute the exhaust purification apparatus 10 are disposed downstream of the turbocharger 27 of the exhaust pipe 12. A filter is installed.

  The turbocharger 27 has a turbine (not shown) and a compressor connected to the turbine. When exhaust gas flows from the engine 11 into the turbocharger 27, the turbine is rotated by the flow of the exhaust gas, and the rotation of the turbine. Along with this, the compressor rotates to suck air from the intake pipe 22a into the turbocharger 27 and pressurize it. The air pressurized by the turbocharger 27 is supplied to each intake port 20 of the engine 11 through the intake pipe 22b.

  The cylinder head 13 is provided with an electronically controlled fuel injection valve 31 that directly injects fuel into the combustion chamber 17 of each cylinder. The fuel injection valve 31 has a predetermined fuel pressure from a common rail (not shown). Controlled high pressure fuel is supplied.

  Here, in the present embodiment, a diesel oxidation catalyst (hereinafter simply referred to as an oxidation catalyst) 32 and a NOx trap catalyst 33 which are exhaust purification catalysts, an exhaust purification filter, and an exhaust pipe 12 downstream of the turbocharger 27. A diesel particulate filter (DPF: Diesel Particulate Filter: hereinafter referred to as DPF) 34 is arranged in order from the upstream side. Further, as will be described in detail later, an injector that injects fuel (light oil) as a reducing agent (additive) into the exhaust pipe (exhaust passage) 12a in the exhaust pipe 12a between the turbocharger 27 and the oxidation catalyst 32. 50 is provided.

The oxidation catalyst 32 is formed, for example, by supporting a noble metal such as platinum (Pt) or palladium (Pd) on a honeycomb structure carrier made of a ceramic material. In the oxidation catalyst 32, when exhaust gas flows, nitrogen monoxide (NO) in the exhaust gas is oxidized to generate nitrogen dioxide (NO ₂ ). In addition, in order for the oxidation reaction in the oxidation catalyst 32 to occur, the oxidation catalyst 32 needs to be heated to a predetermined temperature or higher. Therefore, the oxidation catalyst 32 may be disposed as close to the engine 11 as possible. preferable. This is because the oxidation catalyst 32 is heated by the heat of the engine 11 and the oxidation catalyst 32 can be heated to a predetermined temperature or higher in a relatively short time even when the engine is started.

In the NOx trap catalyst 33, for example, a noble metal such as platinum (Pt) or palladium (Pd) is supported on a honeycomb structure carrier made of aluminum oxide (AL ₂ O ₃ ), and barium (Ba) or the like is used as a trapping agent. An alkali metal or alkaline earth metal is supported. The NOx trap catalyst 33 temporarily traps NOx in the oxidizing atmosphere, that is, NO ₂ generated by the oxidation catalyst 32, or NO remaining in the exhaust gas without being oxidized by the oxidation catalyst 32, for example, In a reducing atmosphere containing carbon (CO), hydrocarbon (HC), etc., NOx is released and reduced to nitrogen (N ₂ ) or the like.

Further, most of the NO ₂ produced by the oxidation catalyst 32 is adsorbed / decomposed (reduced) by the NOx trap catalyst 33, and the remaining NO _{2 that} has not been adsorbed / decomposed is purified by the reaction in the DPF 34. .

  Normally, most of the exhaust gas discharged from the engine 11 is occupied by NO and the amount of HC is very small. Therefore, the inside of the NOx trap catalyst 33 becomes an oxidizing atmosphere, and the NOx trap catalyst 33 only adsorbs NOx. NOx that has been released is not decomposed (reduced). For this reason, when a predetermined amount of NOx is adsorbed to the NOx trap catalyst 33, fuel (light oil) as an additive is injected from the injector 50 fixed to the exhaust pipe 12 a between the turbocharger 27 and the oxidation catalyst 32. It has become so. As a result, the exhaust gas mixed with fuel passes through the oxidation catalyst 32 and is supplied to the NOx trap catalyst 33. The inside of the NOx trap catalyst 33 becomes a reducing atmosphere, and the adsorbed NOx is decomposed (reduced). The NOx trap catalyst 33 traps and decomposes (reduces) sulfur oxide (SOx) as well as nitrogen oxide (NOx).

  The DPF 34 is a filter having a honeycomb structure made of, for example, a ceramic material. In the DPF 34, for example, an exhaust gas passage 38 in which an upstream end is opened and a downstream end is closed and a downstream end are provided. Exhaust gas passages 39 opened and closed at the upstream end are alternately arranged. The exhaust gas first flows into the exhaust gas passage 38 whose upstream end is opened, and the exhaust whose downstream end is opened from the porous wall surface provided between the adjacent exhaust gas passages 39. The gas flows into the gas passage 39 and flows downstream, and in this process, particulate matter (PM) in the exhaust gas collides with the wall surface or is adsorbed and captured.

The trapped PM is oxidized (combusted) by NO ₂ in the exhaust gas and discharged as CO ₂ , and NO ₂ remaining in the DPF 34 is decomposed into N ₂ and discharged. That is, the DPF 34 can purify the exhaust gas and greatly reduce PM and NOx emissions. Moreover, the performance of the DPF 34 is regenerated to some extent by burning PM.

Here, since NOx is normally adsorbed by the NOx trap catalyst 33 as described above, the amount of NO _{2 in} the exhaust gas supplied to the DPF 34 is small, and PM is gradually deposited on the DPF 34. When a predetermined amount of PM accumulates in the DPF 34, a predetermined amount of fuel is injected from the injector 50 fixed to the exhaust pipe 12a. As described above, when the fuel is mixed with the exhaust gas, the NOx trapped by the NOx trap catalyst 33 is reduced, so that NOx (NO ₂ ) contained in the exhaust gas is not absorbed by the NOx trap catalyst 33. To the DPF 34. As a result, PM combustion in the DPF 34 is promoted.

  An exhaust temperature sensor 40 is provided in the vicinity of the upstream side of the oxidation catalyst 32, the NOx trap catalyst 33 and the DPF 34, and in the vicinity of the downstream side of the DPF 34, respectively. The temperature of the exhaust gas flowing into the NOx trap catalyst 33 and the DPF 34 and the temperature of the exhaust gas discharged from the oxidation catalyst 32, the NOx trap catalyst 33 and the DPF 34 are detected. Further, an oxygen concentration sensor 41 for detecting the oxygen concentration in the exhaust gas is provided in the vicinity of the upstream side of the oxidation catalyst 32 and the DPF 34. The vehicle is provided with an electronic control unit (ECU) (not shown). The ECU includes an input / output device, a storage device for storing a control program and a control map, a central processing unit, a timer and a counter. There is a kind. The ECU performs comprehensive control of the engine 11 and the exhaust purification device 10 based on information from the sensors.

  FIG. 2 is an enlarged cross-sectional view showing a main part of the exhaust emission control device according to the first embodiment, and FIG. As shown in FIG. 2, the injector 50 for injecting fuel as a reducing agent is disposed in a direction substantially orthogonal to the exhaust pipe (exhaust passage) 12a and is fixed to the exhaust pipe 12a in this embodiment. It is held by the member 60 and a fixing member 70 fixed to the mounting member 60.

  The mounting member 60 is formed with a communication passage 61 having one end communicating with an exhaust pipe (exhaust passage) 12a. A mounting hole 62 in which the injector 50 is mounted is formed at the other end of the communication passage 61. Yes. Further, a cooling water channel 63 that is a cooling water channel is formed around the mounting hole 62. The injector 50 is mounted in the mounting hole 62 of the mounting member 60, and is fixed to the mounting member 60 by the fixing member 70 in a state where the distal end surface 52 where the nozzle 51 opens is exposed in the communication path 61. The fixing member 70 is detachably fixed to the mounting member 60 by a fastening member such as a bolt, for example.

  Here, as shown in FIGS. 2 and 3, scraping means 80 having a sliding member 81 is disposed in the communication path 61 of the mounting member 60 in the vicinity of the injector 50. The scraping means 80 scrapes off deposits deposited on the tip surface 52 as the sliding member 81 slides on the tip surface 52 of the injector 50 as described below.

  The scraping means 80 includes a sliding member 81 and a biasing member 82 that biases the sliding member 81. The sliding member 81 is formed of a plate-like member made of a unidirectional shape memory alloy that memorizes the shape along the peripheral wall of the communication path 61, and only one end thereof is fixed to the peripheral wall portion of the communication path 61. .

  The urging member 82 is disposed between the other end portion of the sliding member 81 and the mounting member 60 and urges the sliding member 81 toward the central portion of the communication path 61, that is, the injector 50. Specific examples of the urging member 82 include a compression coil spring, but the shape and the like are not particularly limited as long as the sliding member 81 can be urged.

  In addition, the mounting member 60 is formed with a recess 64 in the peripheral wall portion of the communication path 61 in which the sliding member 81 is accommodated. The sliding member 81 stores the shape accommodated in the concave portion 64. When the sliding member 81 becomes a predetermined temperature or more as the temperature in the communication passage 61 rises, the sliding member 81 is deformed by its restoring force. The recess 64 is accommodated. At this time, the sliding member 81 is accommodated in the recess 64 without substantially protruding. That is, the sliding member 81 constitutes a part of the peripheral wall of the communication path 61 in a state where it is accommodated in the recess 64.

  In the present embodiment, when the engine 11 is in an operating state and the sliding member 81 is at a predetermined temperature or higher due to high-temperature exhaust gas flowing through the exhaust pipe (exhaust passage) 12a and the communication passage 61, the sliding member 81 A part of the peripheral wall of the communication path 61 is held while being accommodated in the recess 64 (see FIG. 3A).

  On the other hand, when the engine 11 is stopped and the temperature of the sliding member 81 is lower than a predetermined temperature, for example, room temperature, the sliding member 81 is driven by the spring force of the biasing member 82 as shown in FIG. Is deformed toward the center portion of the communication path 61 and slides on the tip surface 52 of the injector 50. When the engine 11 is restarted from a stopped state and the temperature of the sliding member 81 becomes equal to or higher than a predetermined temperature, the sliding member 81 is deformed by its restoring force and slides on the tip surface 52 of the injector 50, and again. Then, it is accommodated in the recess 64 of the mounting member 60 (FIG. 3A).

  Thus, the sliding member 81 exhibits a restoring force stronger than the spring force of the biasing member 82 when the temperature is equal to or higher than the predetermined temperature. On the other hand, when the temperature of the sliding member 81 is lower than the predetermined temperature, the sliding member 81 is flexible enough to be deformed by the spring force of the biasing member 82. That is, the biasing member 82 exhibits a spring force that can deform the sliding member 81 when the temperature is lower than the predetermined temperature.

  Then, as described above, the sliding member 81 slides on the front end surface 52 of the injector 50, so that the deposit accumulated on the front end surface 52 of the injector 50 is scraped off.

  In such an exhaust purification device 10 of this embodiment, problems such as clogging of the nozzle 51 due to deposit do not occur even if the maintenance work for periodically removing the injector 50 and removing the deposit is not performed. In the present embodiment, since the sliding member 81 constitutes a part of the peripheral wall of the communication path 61, fuel injection is not hindered by the sliding member 81. That is, the communication passage 61 that is a passage through which the fuel passes is not narrowed. Therefore, the fuel can always be supplied satisfactorily from the injector 50 into the exhaust pipe (exhaust passage) 12a. Furthermore, since the scraping means 80 operates according to the temperature change accompanying the on / off of the engine 11 as described above, for example, the deposit can be reliably removed without requiring electrical control or the like.

  In the present embodiment, the sliding member 81 is formed of a unidirectional shape memory alloy, but may be formed of, for example, a bidirectional shape memory alloy. That is, the scraping means 80 may be composed of only the sliding member 81 made of a bidirectional shape memory alloy. Of course, even with such a configuration, the sliding member 81 slides on the front end surface 52 of the injector 50 as the engine 11 is turned on and off, and the deposit accumulated on the front end surface 52 of the injector 50 is scraped off.

(Embodiment 2)
FIG. 4 is an enlarged cross-sectional view showing a main part of the exhaust emission control device according to the second embodiment, and FIG. 5 is a cross-sectional view taken along the line BB ′ of FIG.

  As shown in FIGS. 4 and 5, the present embodiment is an example in which the scraping means 80A includes a sliding member 81A and a moving means 90 for moving the sliding member 81A. That is, the sliding member 81A does not deform itself and moves with the deformation of the moving means 90 connected to the sliding member 81A.

  The moving means 90 is provided with a first urging member 91 made of a spring member that urges the sliding member 81A toward the central portion of the communication path 61, and the urging force of the first urging member 91 under a predetermined condition. The second biasing member 92 is configured to be capable of biasing the sliding member 81A.

  For example, a compression coil spring is preferably used as the first urging member 91, but the first urging member 91 may be any member that can urge the sliding member 81 </ b> A by a spring force, and its material and shape. Etc. are not particularly limited.

  In the present embodiment, the second urging member 92 is made of a shape memory alloy that stores a contracted shape, and a plurality of second urging members 92 are arranged around the first urging member 91. When the second urging member 92 becomes a predetermined temperature or higher as the temperature in the communication passage 61 rises, the sliding member 81A is urged against the urging force of the first urging member 91. That is, the second urging member 92 exerts a restoring force (urging force) stronger than the first urging member 91 to move the sliding member 81 </ b> A when the temperature exceeds a predetermined temperature. The second urging member 92 is formed in a coil shape in the present embodiment, but of course, the shape of the second urging member 92 is not particularly limited.

  In the exhaust purification apparatus 10 having such a configuration, the engine 11 is in an operating state, and the second urging member 92 exceeds a predetermined temperature by the high-temperature exhaust gas flowing through the exhaust pipe (exhaust passage) 12a and the communication passage 61. Then, the sliding member 81 </ b> A is held in the recessed portion 64 by the restoring force (biasing force) of the second urging member 92. That is, the sliding member 81A is accommodated in the recess 64 by the urging force of the second urging member 92 resisting the urging force (spring force) of the first urging member 91 (FIG. 4A).

  On the other hand, when the engine 11 is stopped and the temperature of the second urging member 92 is lower than a predetermined temperature, for example, room temperature, the urging force of the second urging member 92 is weakened and the first urging member 91 is reduced. The urging power of is demonstrated. Due to the urging force of the first urging member 91, the sliding member 81A moves toward the central portion of the communication path 61 and slides on the tip surface 52 of the injector 50 (FIG. 4B). When the engine 11 is restarted and the second urging member 92 reaches a predetermined temperature or higher, the restoring force (the urging force) of the second urging member 92 against the urging force of the first urging member 91. The sliding member 81A slides on the distal end surface 52 of the injector 50 and is accommodated in the recess 64 (FIG. 4A).

  Even in such an exhaust purification device 10 of this embodiment, the deposit accumulated on the injector 50 is surely scraped off by the sliding member 81A as in the above-described embodiment, so that the exhaust pipe (exhaust gas) is discharged from the injector 50. The fuel can always be satisfactorily supplied into the passage 12a.

  In the present embodiment, a plurality of second urging members 92 are arranged around the first urging member 91 to constitute the moving means 90. However, the first urging member 91 and the second urging member 91 are configured as described above. The arrangement, the number, and the like of the urging members 92 are not particularly limited, and may be appropriately determined in consideration of the urging forces exerted by the first urging member 91 and the second urging member 92.

  The sliding member 81 </ b> A may be provided at any position on the inner peripheral surface of the communication passage 61, but is preferably provided on the downstream side of the exhaust passage 12 a of the communication passage 61. Since deposits are likely to accumulate on the inner surface of the communication passage 61 on the downstream side of the exhaust passage 12a, the deposit can be scraped off more favorably by providing the sliding member 81A at this portion.

  Furthermore, in this embodiment, one scraping means 80 is provided around the injector 50, but a plurality of scraping means 80 may of course be provided.

(Embodiment 3)
FIG. 6 is an enlarged cross-sectional view showing a main part of the exhaust gas purification apparatus according to the third embodiment.

  As shown in FIG. 6, the present embodiment is an example in which the scraping means 80B includes a sliding member 81B and a moving means 90A for moving the sliding member. That is, as in the second embodiment, the sliding member 81B does not deform itself and moves with the deformation of the moving means 90A connected to the sliding member 81B.

  The moving means 90A of the present embodiment includes a first urging member 91A composed of a spring member that urges the sliding member 81B toward the center of the communication path 61, and a first urging member 91A under a predetermined condition. And a second urging member 92A capable of urging the sliding member 81A against this urging force.

  For example, a compression coil spring is preferably used as the first urging member 91A. However, the first urging member 91 only needs to be able to urge the sliding member 81B by a spring force, and its material and shape are used. Etc. are not particularly limited.

  The second urging member 92A is an air actuator that urges the sliding member 81B by making the inside negative pressure, and is arranged in the first urging member 91A that is a compression coil spring. For example, a vacuum pump (not shown) used for opening and closing various valves and the like is connected to the second urging member 92A via a suction pipe 93. For this reason, when the engine 11 is in an operating state, the inside of the second urging member 92A is sucked through the suction pipe 93 and has a negative pressure, and the first urging member 91A has a negative pressure. The sliding member 81B is urged against the urging force (spring force). Therefore, the sliding member 81B is accommodated in the recessed part 64, and the state is maintained.

  On the other hand, when the engine 11 is stopped, the pressure inside the second urging member 92A gradually rises to atmospheric pressure, and the spring force of the first urging member 91A acts on the sliding member 81B. That is, the sliding member 81B slides on the distal end surface 52 of the injector 50 by the biasing force (spring force) of the first biasing member 91A.

  Of course, even in the exhaust purification device 10 of the present embodiment, the deposit is reliably scraped off by the sliding member 81B as in the above-described embodiment, so that the fuel is injected from the injector 50 into the exhaust pipe (exhaust passage) 12a. Can always supply well.

  In the present embodiment, the sliding member 81B is biased toward the central portion of the communication path 61 by the first biasing member 91A. However, the sliding is performed by the first biasing member 91A made of a spring member. The member 81B may be biased in the reverse direction (toward the peripheral wall of the communication path 61). In this case, an air actuator that urges the sliding member 81B by increasing the internal pressure may be employed as the second urging member 92A.

(Other embodiments)
Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment. For example, in the above-described embodiment, the sliding member constitutes a part of the peripheral wall of the communication path, but the sliding member is arranged so as not to prevent the injection of fuel (reducing agent) from the injector. Of course, it is not necessary to constitute a part of the peripheral wall of the communication path.

  In the above-described Embodiments 2 and 3, the moving means for moving the sliding member is illustrated, but of course, the moving means is not limited to these configurations. For example, a motor or the like is employed. You can also.

  In the above-described embodiment, as an exhaust purification device, an oxidation catalyst and NOx trap catalyst that are exhaust purification catalysts and a DPF that is an exhaust purification filter are provided in an exhaust pipe (exhaust passage) from the upstream side as an oxidation catalyst, Although an example in which the NOx trap catalyst and the DPF are arranged in the order is given, the arrangement and types of the exhaust purification catalyst and the exhaust purification filter are not particularly limited.

  For example, as shown in FIG. 7A, the NOx trap catalyst 33, the oxidation catalyst 32, and the DPF 34 may be arranged in this order in the exhaust pipe 12 on the downstream side of the turbocharger 27. Further, for example, as shown in FIG. 7B, the NOx trap catalyst 33 and the DPF 34 may be sequentially arranged in the exhaust pipe 12 on the downstream side of the turbocharger 27 without providing the oxidation catalyst 32. . Further, for example, as shown in FIG. 7C, a configuration may be adopted in which only the DPF 34A having a catalytic function is provided without providing the exhaust purification catalyst. That is, only the DPF 34A, which is an exhaust purification filter that also serves as an exhaust purification catalyst, may be provided. In any case, the above-described effects can be obtained by adopting the present invention as long as the configuration has an injector for injecting an additive such as fuel upstream of the exhaust purification catalyst or the exhaust purification filter.

  In the above-described embodiment, the NOx trap catalyst that decomposes (reduces) NOx using fuel (light oil) as a reducing agent is exemplified as the exhaust gas purification catalyst that decomposes (reduces) NOx, but is not limited thereto. For example, a so-called SCR (Selective Catalytic Reduction) that selectively adsorbs NOx in exhaust gas to a catalyst and injects ammonia or urea as a reducing agent from an injector to decompose (reduce) NOx may be used.

  In the above-described embodiment, the example in which the reducing agent is added as the additive has been described. However, the additive is not limited to the purpose of the reducing action, and if it is added to the exhaust system, for example, by combustion A fuel for the purpose of raising the temperature may be used.

  Furthermore, in the above-described embodiment, an example of the configuration of an intake / exhaust system including a turbocharger as a supercharger is shown. However, the present invention is not particularly limited thereto. For example, the supercharger is not necessarily provided. Further, a cooling exhaust gas recirculation device having a cooling exhaust gas recirculation passage between the exhaust passage and the intake passage, that is, a so-called EGR device may be provided.

1 is a diagram illustrating a schematic configuration of an exhaust purification device according to Embodiment 1. FIG. FIG. 3 is an enlarged cross-sectional view showing a main part of the exhaust emission control device according to the first embodiment. 1 is a cross-sectional view showing a main part of an exhaust purification device according to Embodiment 1. FIG. FIG. 4 is an enlarged cross-sectional view showing a main part of an exhaust purification device according to a second embodiment. FIG. 5 is a cross-sectional view showing a main part of an exhaust emission control device according to Embodiment 2. FIG. 6 is an enlarged cross-sectional view showing a main part of an exhaust emission control device according to Embodiment 3. It is a schematic block diagram which shows the modification of an exhaust gas purification apparatus.

Explanation of symbols

10 Exhaust purification device 11 Engine 12 Exhaust pipe (exhaust passage)
13 Cylinder Head 14 Cylinder Block 15 Cylinder Bore 16 Piston 17 Combustion Chamber 18 Connecting Rod 19 Crankshaft 20 Intake Port 21 Intake Manifold 22 Intake Pipe 23 Intake Valve 24 Exhaust Port 25 Exhaust Manifold 26 Exhaust Valve 27 Turbocharger 31 Fuel Injection Valve 32 Oxidation Catalyst 33 NOx trap catalyst 34 DPF
40 Exhaust Temperature Sensor 41 Oxygen Concentration Sensor 50 Injector 51 Nozzle 52 Front End Surface 60 Mounting Member 61 Communication Path 62 Mounting Hole 63 Cooling Water Channel 64 Recess 70 Fixing Member 80 Scraping Means 81 Sliding Member 82 Biasing Member 90 Moving Means 91 First Urging member 92 second urging member 93 suction pipe

Claims (7)

An exhaust purification catalyst disposed in an exhaust passage communicating with the engine, and an injector provided upstream of the exhaust purification catalyst and injecting an additive into the exhaust passage;
The injector is fixed in a communicating path connected to the exhaust passage in a state in which the tip end face is exposed, and the communicating path is attached to the tip end face of the injector by a sliding member that slides on the tip end face of the injector. An exhaust emission control device comprising scraping means for scraping the deposited deposit.   The exhaust purification device according to claim 1, wherein the sliding member also functions as a part of a peripheral wall of the communication path.   The said sliding member consists of a plate-shaped shape memory alloy which is distribute | arranged along the circumferential direction of the said communicating path, and one end was fixed to the surrounding wall of the said communicating path. Exhaust purification equipment.   The scraping means has the sliding member and a moving means for moving the sliding member, and the moving means biases the sliding member toward the central portion of the communication path. A first urging member made of a member, and a second urging member capable of urging the sliding member against the urging force of the spring member under a predetermined condition. The exhaust emission control device according to claim 1 or 2.   The exhaust emission control device according to claim 4, wherein the second urging member is made of a shape memory alloy that stores a shape in a contracted state.   The exhaust emission control device according to claim 4, wherein the second urging member is an air actuator that urges the sliding member by setting a negative pressure inside.   The exhaust purification device according to claim 1, wherein the sliding member is provided at least on the downstream side of the exhaust passage of the communication passage.

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