JP2014152705A - Exhaust gas purification device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust gas purification device capable of facilitating assembling work and preventing urea water injected through a urea water injection nozzle from crystallizing.SOLUTION: An exhaust gas purification device comprises: a first case 28 which removes particulate substances in exhaust gas of an engine 1; a second case 29 which removes nitrogen oxide in the exhaust gas of the engine 1; and a urea water mixing pipe 72 which connects an exhaust outlet of the first case 28 with an exhaust inlet of the second case 29. The exhaust gas purification device injects the urea water into the urea mixing pipe 72. The exhaust gas purification device also has a structure where: the first case 28, the second case 29 and the urea mixing pipe 72 are arranged in parallel with a moving direction of exhaust gas; an exhaust gas outlet pipe 35 is provided on an edge face at an exhaust gas outlet side of the first case 28; an exhaust gas inlet pipe 36 is provided on a side face at an exhaust gas inlet side of the second case 29; the urea mixing pipe 72 is connected to the exhaust gas outlet pipe 35 through a bellows connecting pipe 74; and a urea water injection nozzle 76 is arranged between the urea mixing pipe 72 and the bellows connecting pipe 74.

Description

  The present invention relates to an exhaust gas purifying apparatus such as a diesel engine mounted on an agricultural machine (tractor, combine) or construction machine (bulldozer, hydraulic excavator, loader), and more specifically, particulates contained in the exhaust gas. The present invention relates to an exhaust gas purification device that removes substances (soot, particulates), nitrogen oxides (NOx) contained in exhaust gas, and the like.

  Conventionally, an exhaust gas purification case (hereinafter referred to as a DPF case) having a diesel particulate filter or a urea selective catalyst reduction type SCR catalyst has been installed in the exhaust path of a diesel engine as an exhaust gas aftertreatment device. There is known a technique for purifying exhaust gas discharged from a diesel engine by providing an exhaust gas purification case (hereinafter referred to as an SCR case) or the like and introducing exhaust gas into the DPF case or SCR case (for example, patents) References 1-3).

JP 2009-85064 A JP 2009-85065 A JP 2008-196328 A

  As in Patent Document 1, in the structure in which the urea mixing pipe is assembled obliquely with respect to the DPF case and the SCR case so that the exhaust gas flow of the engine is N-shaped, the exhaust gas outlet side of the DPF case is When both end sides of the urea mixing pipe for injecting urea water are connected to the side face and the side face on the SCR case exhaust gas inlet side, it is necessary to form both ends of the urea mixing pipe in a complicated manner. There is a problem that the exhaust passage structure of the case and the SCR case cannot be easily configured.

  On the other hand, as in Patent Document 2 or Patent Document 3, when the urea mixing pipe is piped to the DPF case and the SCR case so that the axis of the urea mixing pipe is parallel to the axis of the DPF case and the SCR case, Compared to Patent Document 1, the exhaust flow path structure of the DPF case and the SCR case can be configured easily, but the DPF case and the SCR case are fixed integrally to each other, and the urea mixing pipe or the welded portion for connecting the deformed portion is deformed. It is necessary to prevent damage, and the exhaust passage structure of the DPF case and the SCR case cannot be configured at low cost. Also, in the structure in which the DPF case, the SCR case, and the urea mixing pipe are integrally formed as a single component as in Patent Document 1, Patent Document 2, or Patent Document 3, the engine is mounted on an agricultural machine or a construction machine. In an assembly plant or the like, it is necessary to handle the DPF case, the SCR case, and the urea mixing tube as a single heavy-weight part, and there is a problem that the assembly workability cannot be easily improved.

  Therefore, the present invention seeks to provide an exhaust gas purifying apparatus that has been improved by examining these current conditions.

  According to the first aspect of the present invention, a first case for removing particulate matter in the exhaust gas of the engine, a second case for removing nitrogen oxides in the exhaust gas of the engine, and an exhaust gas inlet of the second case In the exhaust gas purification apparatus comprising a urea mixing pipe that connects an exhaust gas outlet of the first case, the first case and the second case are arranged in parallel, and urea water is injected into the urea mixing pipe. 1 case, the second case, and the urea mixing pipe are arranged in parallel to the exhaust gas moving direction, and an exhaust gas outlet pipe is provided on an end surface of the first case on the exhaust gas outlet side, An exhaust gas inlet pipe is provided on a side surface of the second case on the exhaust gas inlet side, and an exhaust gas outlet pipe is connected to the urea mixing pipe via a bellows-like connecting pipe, and between the urea mixing pipe and the bellows-like connecting pipe. Urea water injection nose It is obtained by placing a.

  According to a second aspect of the present invention, in the exhaust gas purifying apparatus according to the first aspect, an exhaust connection pipe for taking in the exhaust gas of the engine is connected to a side surface of the first case on the exhaust gas inlet side, The second case is displaced to the exhaust gas outlet side of the first case, and the end surface on the exhaust gas outlet side of the second case protrudes from the end surface on the exhaust gas outlet side of the first case, The bellows-like connecting pipe is disposed on the outer side of the second case on the exhaust gas outlet side.

  According to the first aspect of the invention, the first case for removing particulate matter in the exhaust gas of the engine, the second case for removing nitrogen oxides in the exhaust gas of the engine, and the exhaust gas inlet of the second case In the exhaust gas purifying apparatus, wherein the exhaust gas purifying apparatus includes a urea mixing pipe that connects an exhaust gas outlet of the first case, the first case and the second case are arranged in parallel, and urea water is injected into the urea mixing pipe. The first case, the second case, and the urea mixing pipe are arranged in parallel to the exhaust gas movement direction, and an exhaust gas outlet pipe is provided on an end surface of the first case on the exhaust gas outlet side. An exhaust gas inlet pipe is provided on a side surface of the second case on the exhaust gas inlet side, and an exhaust gas outlet pipe is connected to the urea mixing pipe via a bellows-like connecting pipe, and the urea mixing pipe and the bellows-like connecting pipe are connected to each other. Urea water jet Since the nozzles are arranged, the first case and the second case are separately performed on the engine or the traveling machine body by separately performing the first case and the second case. Can be connected to the first case and the second case via the bellows-like connecting pipe. That is, the exhaust flow path structure of the first case and the second case can be configured easily and at low cost, but in an assembly plant or the like where an engine is mounted on an agricultural machine or a construction machine, the first case and The second case can be handled as parts independent from each other, and assembly workability can be easily improved. In particular, by adjusting the mounting position of the bellows-like connecting pipe, the second case can be easily attached to a support member different from the first case, and the exhaust gas movement lower side of the bellows-like connecting pipe, By spraying urea water from the urea water injection nozzle toward the urea mixing pipe, it is possible to prevent the urea water injected from the urea water injection nozzle from adhering to the inner surface of the bellows-like connecting pipe and crystallization. It is.

  According to the invention of claim 2, the exhaust connection pipe for taking in the exhaust gas of the engine is connected to the side surface of the first case on the exhaust gas inlet side and the exhaust gas outlet side of the first case is connected to the exhaust gas outlet side. The second case is deflected so that the end surface on the exhaust gas outlet side of the second case protrudes from the end surface on the exhaust gas outlet side of the first case, and the outer side of the second case on the exhaust gas outlet side Since the bellows-like connecting pipe is disposed on the side, exhaust gas can be supplied from both side surfaces to the first case and the second case, and inside each of the first case and the second case. Can ensure good diffusion of exhaust gas. Further, the urea mixing tube and the bellows-like connecting tube can be compactly supported inside a rectangular frame (plan view) surrounding the first case and the second case, and the bellows-like connecting tube is provided on the side surface of the second case. Can be installed close to each other, can reduce the temperature drop of the bellows-like connecting pipe, and easily lowers the temperature of the exhaust gas from the first case to the urea mixing pipe when passing through the bellows-like connecting pipe Can be prevented.

It is a right view of the exhaust-gas purification apparatus which shows 1st Embodiment. It is the left side view. It is the same top view. It is the same rear view. It is the same front view. It is the back perspective view seen from the left side. It is the front perspective view seen from the same right side. It is an expansion perspective view of the front side of an exhaust-gas purification apparatus. It is an expansion perspective view of the back side of an exhaust gas purification device.

  DESCRIPTION OF EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings. 1 is a right side view of the exhaust gas purifying device, FIG. 2 is a left side view thereof, FIG. 3 is a plan view thereof, FIG. 4 is a rear view thereof, FIG. 5 is a front view thereof, and FIGS. is there. The overall structure of the exhaust gas purification device will be described with reference to FIGS.

  As shown in FIGS. 1 to 7, as an exhaust gas purification device 27 for purifying exhaust gas discharged from each cylinder of the multi-cylinder diesel engine 1, diesel that removes particulate matter in the exhaust gas of the diesel engine 1. A first case 28 as a particulate filter (DPF case) and a second case 29 as a urea selective catalytic reduction system (SCR case) for removing nitrogen oxides in the exhaust gas of the diesel engine 1 are provided. As shown in FIG. 3, the oxidation catalyst 30 and the soot filter 31 are installed in the first case 28. The second case 29 includes an SCR catalyst 32 and an oxidation catalyst 33 for reducing urea selective catalyst.

  Exhaust gas discharged from each cylinder of the diesel engine 1 to the exhaust manifold 6 is discharged to the outside via the exhaust gas purification device 27 and the like. The exhaust gas purification device 27 is configured to reduce carbon monoxide (CO), hydrocarbons (HC), particulate matter (PM), and nitrogen oxides (NOx) in the exhaust gas of the diesel engine 1. doing.

  The first case 28 and the second case 29 are configured in a substantially cylindrical shape extending long in the horizontal direction perpendicular to the output shaft (crankshaft) 4 of the diesel engine 1 in plan view. Of the peripheral side surface of the first case 28, a DPF inlet pipe 34 for taking in exhaust gas is provided on the peripheral side surface on the upper side in the exhaust gas movement direction. Further, a DPF outlet pipe 35 for discharging exhaust gas is provided on the side end surface of the first case 28 on the lower side in the exhaust gas movement direction. Similarly, an SCR inlet pipe 36 for taking in exhaust gas is provided on the peripheral side surface of the second case 29 on the upper side in the exhaust gas movement direction. In addition, an SCR outlet pipe 37 that exhausts exhaust gas is provided on the side end surface of the second case 29 on the lower side in the exhaust gas movement direction.

  Further, a supercharger 38 for forcibly sending air to the diesel engine 1 is disposed at the exhaust gas outlet of the exhaust manifold 6. The DPF inlet pipe 34 is communicated with the exhaust manifold 6 via the supercharger 38 to introduce the exhaust gas of the diesel engine 1 into the first case 28, while the urea mixing pipe 72 described later is connected to the DPF outlet pipe 35. The SCR inlet pipe 36 is connected, and the exhaust gas from the first case 28 is introduced into the second case 29. A urea mixing pipe 72 is detachably bolted to the SCR inlet pipe 36 by a flange body 40.

  As shown in FIGS. 1 to 3, one end side of a flexible heat-resistant rubber gas discharge pipe 71 is connected to the exhaust gas outlet pipe 70 of the supercharger 38, and the other end of the gas discharge pipe 71 is connected to the DPF inlet pipe 34. The first case 28 is connected to the supercharger 38 via the gas discharge pipe 71, and the exhaust gas of the exhaust manifold 6 is moved from the supercharger 38 to the first case 28. .

  Further, one end side of a metal bellows-like connecting pipe 74 is connected to the DPF outlet pipe 35, and the other end side of the bellows-like connecting pipe 74 is connected to the exhaust gas inlet side of the elbow pipe-shaped urea water injection pipe 73, The exhaust gas outlet side of the urea water injection pipe 73 is connected to one end side of the urea mixing pipe 72, and the SCR inlet pipe 36 is connected to the other end side of the urea mixing pipe 72 by the flange body 40. That is, the SCR inlet pipe 36 is connected to the DPF outlet pipe 35 via the bellows-like connecting pipe 74, the urea water injection pipe 73, and the urea mixing pipe 72, and the second case 29 is connected to the first case 28. The exhaust gas is configured to move from the first case 28 to the second case 29. The bellows-like connecting pipe 74 has a bellows shape and is formed to be foldable and extendable.

  As shown in FIG. 1, a urea water tank 75 that stores urea water, a urea water injection nozzle 76 for supplying urea, and a urea water injection electric pump 77 that pumps the urea water in the urea water tank 75 to the urea water injection nozzle 76. Is provided. A urea water injection nozzle 76 is disposed on the nozzle support portion 78 of the urea water injection pipe 73. The urea water injected from the urea water injection nozzle 76 toward the inside of the urea mixing pipe 72 is hydrolyzed at the exhaust gas temperature and generated as ammonia.

  With the above configuration, the urea water in the urea water tank 75 is pumped from the urea water injection pump 77 to the urea water injection nozzle 76, the urea water is injected from the urea water injection nozzle 76 into the urea water injection pipe 73, and the urea water Inside the injection pipe 73 or the connecting pipe 39, urea water from the urea water injection nozzle 76 is mixed with the exhaust gas from the diesel engine 1 as ammonia. The exhaust gas mixed with ammonia (urea water) passes through the second case 29 (SCR catalyst 32, oxidation catalyst 33), nitrogen oxides (NOx) in the exhaust gas are reduced, and the SCR outlet pipe 37 is connected to the outside. To be released. By spraying urea water in the exhaust gas, ammonia gas is generated in the exhaust gas, and the ammonia gas and the exhaust gas are mixed and introduced into the second case 29 from the SCR inlet pipe 36, and the second Nitrogen oxides (NOx) in the exhaust gas are removed by the catalysts 32 and 33 in the case 29.

  Next, with reference to FIGS. 1-9, the attachment structure of the exhaust-gas purification apparatus 27 is demonstrated. A first support leg 81 that supports the DPF inlet pipe 34 side of the first case 28 and a second support leg 82 that supports the DPF outlet pipe 35 side of the first case 28 are provided. A first support leg 81 and a second support leg 82 are erected on the cylinder head 2 of the diesel engine 1. A first case 28 is detachably fixed to the cylinder head 2 via a first support leg 81 and a second support leg 82.

  That is, the first support leg 81 and the second support leg 82 are erected on the opposite side surfaces of the cylinder head 2, and the first case 28 is supported in a posture straddling the cylinder head 2. The longitudinal direction (exhaust gas movement direction) of the cylindrical first case 28 is configured to be directed in the horizontal transverse direction intersecting the engine output shaft 4.

  On the other hand, a radiator 90 arranged to face the cooling fan 24 of the diesel engine 1 is provided. A body frame 91 is erected on the upper surface side of the machine 56 on which the diesel engine 1 is mounted. The radiator 90 is supported on the machine body frame 91. The cooling fan 24 sucks outside air through the radiator 90 and supplies cooling air from the cooling fan 24 to each part of the diesel engine 1.

  1 and 2, the SCR support leg 93 is projected from the second case 29 toward the lower surface, and the lower end side of the SCR support leg 93 is detachably bolted to the body frame 91. Yes. A second case 29 is disposed above the cooling fan 24 or the radiator 90 via the body frame 91 and the SCR support leg 93. The first case 28 is supported at a higher position than the uppermost end of the cooling fan 24 via the first support leg 81 and the second support leg 82, and via the body frame 91 and the SCR support leg 93. The second case 29 is supported at a higher position than the first case 28.

  As shown in FIGS. 1 to 9, a first case 28 for removing particulate matter in the exhaust gas of the diesel engine 1, a second case 29 for removing nitrogen oxides in the exhaust gas of the diesel engine 1, A urea mixing pipe 72 for connecting the exhaust gas outlet of the first case 28 to the exhaust gas inlet of the two cases 29 is provided. The first case 28 and the second case 29 are arranged in parallel, and urea water is placed in the urea mixing pipe 72. In the exhaust gas purifying apparatus for injecting exhaust gas, the first case 28, the second case 29, and the urea mixing pipe 72 are arranged in parallel to the exhaust gas movement direction, and the exhaust gas outlet of the first case 28 A DPF outlet pipe 35 as an exhaust gas outlet pipe is provided on the side end face, an SCR inlet pipe 36 as an exhaust gas inlet pipe is provided on the side surface of the second case 29 on the exhaust gas inlet side, and a urea mixing pipe 72 is provided. Via the bellows-shaped connecting pipe 74 to connect the DPF outlet pipe 35, are arranged urea injection nozzle 76 between the urea mixing tube 72 and the bellows connecting pipe 74. Therefore, the assembly operation of the first case 28 and the assembly operation of the second case 29 are performed separately on the diesel engine 1 or the machine, respectively, so that the first case 28 and the second case 29 are independent. In this state, the urea mixing pipe 72 can be connected to the first case 28 and the second case 29 via the bellows-like connecting pipe 74.

  That is, while the exhaust flow path structure of the first case 28 and the second case 29 can be configured easily and at low cost, in an assembly plant or the like in which the diesel engine 1 is mounted on an agricultural machine or a construction machine, etc. The first case 28 and the second case 29 can be handled as parts independent from each other, and the assembly workability can be easily improved. In particular, the second case 29 can be easily attached to a support member different from the first case 28 by adjusting the attachment position of the deformable bellows-like connecting pipe 74 (correcting the assembling dimensions), and the bellows-like shape can be provided. The urea water injected from the urea water injection nozzle 76 is injected into the bellows-like connection pipe 74 by injecting urea water from the urea water injection nozzle 76 toward the urea mixing pipe 72 on the exhaust gas moving lower side of the connection pipe 74. It can prevent crystallization by adhering to the inner surface.

  Further, as shown in FIGS. 1 to 9, a gas discharge pipe 71 as an exhaust connection pipe for taking in the exhaust gas of the diesel engine 1 is connected to the side surface of the first case 28 on the exhaust gas inlet side, and The second case 29 is displaced to the exhaust gas outlet side of the first case 28 so that the end surface on the exhaust gas outlet side of the second case 29 protrudes from the end surface of the first case 28 on the exhaust gas outlet side. A bellows-like connecting pipe 74 is disposed outside the two cases 29 on the exhaust gas outlet side. Therefore, the exhaust gas can be supplied to both the first case 28 and the second case 29 from the respective side surfaces, and the diffusion of the exhaust gas inside each of the first case 28 and the second case 29 can be ensured satisfactorily.

  Further, the second case 29 is displaced in the exhaust gas movement direction with respect to the first case 28, and the exhaust gas inlet side end surface of the second case 29 is located more than the exhaust gas inlet side end surface of the first case 28. The exhaust gas movement lower end side is displaced and the exhaust gas outlet side end surface of the second case 29 is displaced toward the exhaust gas movement lower end side with respect to the exhaust gas outlet side end surface of the first case 28. That is, the second case 29 is displaced to the exhaust gas outlet side of the first case 28, and the end surface of the second case 29 on the exhaust gas outlet side is more exhaust gas than the end surface of the first case 28 on the exhaust gas outlet side. Since it protrudes on the moving lower side, the urea mixing pipe 72 and the bellows-like connecting pipe 74 can be compactly supported inside a rectangular frame (plan view) surrounding the first case 28 and the second case 29.

  In addition, the bellows-like connecting pipe 74 is brought close to the exhaust gas outlet side end surface of the first case 28 and the side surface of the second case 29, so that the exhaust gas outlet side end surface of the first case 28 and the side surface of the second case 29 The bellows-like connecting pipe 74 can be installed in the formed recessed space, the temperature drop of the bellows-like connecting pipe 74 can be reduced, and the temperature of the exhaust gas from the first case 28 to the urea mixing pipe 72 is reduced by the bellows-like connecting pipe 74. It can be easily prevented from lowering when passing. Therefore, even if urea water flows backward into the bellows-like connecting pipe 74, crystallization of urea water inside the bellows-like connecting pipe 74 can be prevented.

1 Diesel engine 28 1st case 29 2nd case 35 DPF outlet pipe (exhaust gas outlet pipe)
36 SCR inlet pipe (exhaust gas inlet pipe)
71 Gas exhaust pipe (exhaust connection pipe)
72 urea mixing pipe 74 bellows-like connecting pipe 76 urea water injection nozzle

Claims (2)

A first case for removing particulate matter in the exhaust gas of the engine, a second case for removing nitrogen oxides in the exhaust gas of the engine, and an exhaust gas of the first case at the exhaust gas inlet of the second case In an exhaust gas purifying apparatus comprising a urea mixing pipe connecting an outlet, arranging the first case and the second case in parallel, and injecting urea water into the urea mixing pipe,
The first case, the second case, and the urea mixing pipe are arranged in parallel to the exhaust gas movement direction, and an exhaust gas outlet pipe is provided on an end surface of the first case on the exhaust gas outlet side. An exhaust gas inlet pipe is provided on a side surface of the second case on the exhaust gas inlet side, and an exhaust gas outlet pipe is connected to the urea mixing pipe via a bellows-like connecting pipe, so that the urea mixing pipe and the bellows-like connecting pipe are provided. An exhaust gas purifying device characterized in that a urea water injection nozzle is disposed between the two. An exhaust connection pipe for taking in the exhaust gas of the engine is connected to a side surface of the first case on the exhaust gas inlet side, and the second case is displaced to the exhaust gas outlet side of the first case. The end surface on the exhaust gas outlet side of the second case protrudes from the end surface on the exhaust gas outlet side of the first case, and the bellows-like connecting pipe is provided outward of the exhaust gas outlet side of the second case. The exhaust gas purification device according to claim 1, wherein the exhaust gas purification device is disposed.

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