JP5918154B2 - Engine device for work vehicle - Google Patents

Description

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

  In a work vehicle such as a tractor or wheel loader, an opening / closing fulcrum shaft is arranged at the rear of the bonnet for covering the engine in order to improve the efficiency of maintenance work of the engine arranged at the front of the traveling machine body. The bonnet was rotated. Conventionally, a diesel particulate filter (hereinafter referred to as a DPF case) as an exhaust gas purifying device (exhaust gas aftertreatment device) in the exhaust path of a diesel engine, and a urea selective reduction type catalyst are provided. A technique is known in which an internal case (hereinafter referred to as an SCR case) is provided, exhaust gas is introduced into the DPF case and the SCR case, and the exhaust gas discharged from the diesel engine is purified (for example, Patent Document 1). To 3).

JP 2009-74420 A JP 2012-21505 A JP 2012-177233 A

  When the DPF case and the SCR case are assembled apart from the engine as in Patent Document 1 or 2, the temperature of the exhaust gas supplied from the engine to the DPF case or the SCR case decreases, and the diesel particulate filter Therefore, there is a problem that a special device for maintaining the temperature of the exhaust gas in the SCR case at a high temperature is required.

  On the other hand, when the DPF case and the SCR case are assembled close to the engine as in Patent Document 3, the temperature drop of the exhaust gas supplied from the engine to the SCR case is reduced, and the temperature of the exhaust gas in the SCR case is reduced. However, it is difficult to make the engine room compact and the DPF case or the SCR case cannot be supported compactly. There is. Further, in a narrow engine room, there is a problem that assembly workability or maintenance workability of a DPF case or an SCR case cannot be improved.

  Therefore, the present invention seeks to provide an engine device for a work vehicle that has been improved by examining these current conditions.

In order to achieve the above object, an engine device for a work vehicle according to a first aspect of the present invention includes a first case as a diesel particulate filter that removes particulate matter in the exhaust gas of the engine, and the exhaust gas of the engine. A second case as a urea selective reduction catalyst system that removes the nitrogen oxides of the above, and a urea mixing pipe that connects the first case and the second case, and the vehicle body frame on which the left and right traveling wheels are disposed, in the engine device for a working vehicle equipped with an engine, the engine is arranged between the first case and the urea mixing tube and the second case to the output shaft core direction parallel, the upper surface side of the engine first A case is attached, a DPF outlet pipe is provided on the end surface of the first case on the exhaust gas outlet side, and the second outer peripheral surface of the second case is closer to the exhaust gas inlet. The SCR inlet pipe provided at, through the urea mixing tube and connecting the SCR inlet pipe and the DPF outlet pipe, in which is mounted a urea injection nozzle on the upstream side of the urea mixing tube.

According to a second aspect of the present invention, in the engine device for the work vehicle according to the first aspect, the operation vehicle has a driving cabin disposed behind a bonnet in which the engine is installed, and is provided at a lower portion of the driving cabin. urea solution tank for exhaust gas purification between the provided fuel tank and the engine in which the installed.

According to the first aspect of the invention, a first case as a diesel particulate filter that removes particulate matter in engine exhaust gas, and a urea selective reduction catalyst that removes nitrogen oxides in the engine exhaust gas In an engine device for a work vehicle that includes a second case as a system , and a urea mixing pipe that connects the first case and the second case, and the engine is mounted on a body frame in which left and right traveling wheels are arranged. the engine is arranged between the first case and the urea mixing tube and the second case to the output shaft core direction parallel to, attaching the first case on the upper side of the engine, exhaust gas in the first case A DPF outlet pipe is provided on the end surface on the outlet side, an SCR inlet pipe is provided at a location near the exhaust gas inlet on the longitudinal outer peripheral surface of the second case, and the urea mixing pipe is And by connecting the SCR inlet pipe and the DPF outlet pipe, because those that attach the urea injection nozzle on the upstream side of the urea mixing tube, the first case and the longitudinal direction of the second case is the The first case and the second case can be compactly installed by utilizing the upper surface side or the side surface of the engine so as to be parallel to the output shaft of the engine. Further, the first case and the second case can be fixed to the upper surface or the side surface of the engine with high rigidity by a simple support structure provided on the upper surface or the side surface of the engine. In addition, with respect to the vibration of the engine, etc., the mounting interval between the first case and the second case can be kept constant, and each case formed in a long cylindrical outer shape, Exhaust gas piping between the exhaust gas outlet side and the tail pipe can be simplified.

According to the invention of claim 2, a work vehicle in which to place the driving cabin in the rear of the bonnet to the engine it is internally provided, between the fuel tank and the engine which is provided in the lower portion of the driver cabin Since the urea water tank for exhaust gas purification is installed, the urea water tank can be heated by exhaust heat of the engine and the fuel tank, and the aqueous solution temperature in the urea water tank can be maintained above a predetermined level. It is possible to prevent the exhaust gas purification ability of the second case from being lowered in a cold district or the like. The fuel tank refueling port and the urea water tank water refueling port can be arranged close to each other, the fuel refueling work and the urea aqueous solution water refilling work can be performed at the same work place, and the engine fuel or exhaust gas purification This makes it possible to improve the replenishment workability of the urea aqueous solution.

It is a left view of the diesel engine which shows 1st Embodiment. It is the same right view. It is the same front view. It is a left view of the tractor carrying a diesel engine. It is the same top view. It is a left view of an exhaust gas purification apparatus. It is the same right view. It is the same top view. FIG. 9 is an enlarged explanatory view of FIG. 8. It is an enlarged view of the connection part of an SCR inlet pipe and a urea mixing pipe. It is a fragmentary sectional view of the 2nd case. It is AA sectional view taken on the line of FIG. It is explanatory drawing of an exhaust-gas purification | cleaning case. It is explanatory drawing which shows the modification of an exhaust-gas purification | cleaning case. It is a perspective view of the engine part of the tractor which shows 2nd Embodiment. It is a perspective view of the engine part of the tractor which shows 3rd Embodiment. It is a perspective view of the engine part of the tractor which shows 4th Embodiment. It is a right view of the diesel engine which shows 5th Embodiment. It is the left side view. It is the same top view. It is the same front view. It is the same rear view. It is the left perspective view seen from the front. It is the right perspective view seen from the back. It is a left view of the work vehicle. It is a top view of the work vehicle.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings (FIGS. 1 to 12). FIG. 1 is a left side view where an exhaust manifold of a diesel engine is installed, FIG. 2 is a right side view where an intake manifold of the diesel engine is installed, and FIG. 3 is a front view where a cooling fan of the diesel engine is installed. The overall structure of the diesel engine 1 will be described with reference to FIGS.

  As shown in FIGS. 1 to 3, an intake manifold 3 is disposed on one side surface of the cylinder head 2 of the diesel engine 1. The cylinder head 2 is mounted on a cylinder block 5 in which an engine output shaft 4 (crankshaft) and a piston (not shown) are built. An exhaust manifold 6 is disposed on the other side of the cylinder head 2. The front end and the rear end of the engine output shaft 4 are projected from the front and rear surfaces of the cylinder block 5.

  As shown in FIGS. 1 to 3, a flywheel housing 8 is fixed to the rear surface of the cylinder block 5. A flywheel (not shown) is provided in the flywheel housing 8. The flywheel is pivotally supported on the rear end side of the engine output shaft 4. The power of the diesel engine 1 is taken out through the flywheel. Further, an oil pan 11 is disposed on the lower surface of the cylinder block 5.

As shown in FIGS. 1 and 3, an exhaust gas recirculation device (EGR) 15 that takes in exhaust gas for recirculation is arranged in the intake manifold 3. An air cleaner 16 shown in FIG. 4 is connected to the intake manifold 3. The external air that has been dedusted and purified by the air cleaner 16 is sent to the intake manifold 3 and supplied to each cylinder of the diesel engine 1.

  With the above configuration, a part of the exhaust gas discharged from the diesel engine 1 to the exhaust manifold 6 is recirculated from the intake manifold 3 to each cylinder of the diesel engine 1 via the exhaust gas recirculation device 15. The combustion temperature of the diesel engine 1 is lowered, the emission amount of nitrogen oxide (NOx) from the diesel engine 1 is reduced, and the fuel efficiency of the diesel engine 1 is improved.

  A cooling water pump 21 for circulating cooling water in the cylinder block 5 and the radiator 19 shown in FIG. 4 is provided. A cooling water pump 21 is disposed on the side of the diesel engine 1 where the cooling fan 24 is installed. The cooling water pump 21 and the cooling fan 24 are connected to the engine output shaft 4 via the V belt 22 and the like, and the cooling water pump 21 and the cooling fan 24 are driven. While the cooling water is sent from the cooling water pump 21 into the cylinder block 5 via the EGR cooler 18 of the exhaust gas recirculation device 15, the diesel engine 1 is cooled by the cooling fan 24 wind. .

  As shown in FIGS. 1 to 3, as an exhaust gas purifying device 27 for purifying exhaust gas discharged from each cylinder of the diesel engine 1, a diesel parti that removes particulate matter in the exhaust gas of the diesel engine 1. A first case 28 as a curate filter (DPF) and a second case 29 as a urea selective catalytic reduction (SCR) system for removing nitrogen oxides in exhaust gas of the diesel engine 1 are provided. As shown in FIGS. 1 and 2, an oxidation catalyst 30 and a soot filter 31 are provided 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 long cylindrical shape extending in a direction parallel to the output shaft (crankshaft) 4 of the diesel engine 1 in plan view (see FIG. 9). A DPF inlet pipe 34 for taking in exhaust gas and a DPF outlet pipe 35 for discharging exhaust gas are provided on both sides of the first case 28 in the cylindrical shape (one end side and the other end side in the exhaust gas movement direction). Similarly, an SCR inlet pipe 36 that takes in exhaust gas and an SCR outlet pipe 37 that discharges exhaust gas are provided on both sides of the second case 29 (one end side and the other end side in the exhaust gas movement direction).

  Further, a supercharger 38 that forcibly sends 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 SCR is connected to the DPF outlet pipe 35 via the urea mixing pipe 39. The inlet pipe 36 is connected, and the exhaust gas from the first case 28 is introduced into the second case 29. In addition, the DPF outlet pipe 35 and the urea mixing pipe 39 are connected to a bellows-like connecting pipe 41 that can be bent and stretched. In addition, the proximal end side of the pipe support bracket 40 is fixed to the outer peripheral surface of the second case 29, and the SCR inlet pipe 36 and the urea mixing pipe 39 are detachably fixed by the pipe bracket 40.

  As shown in FIG. 1, each of the multi-cylinder injectors (not shown) of the diesel engine 1 includes a fuel pump 42 and a common rail 43 that connect the fuel tank 45 shown in FIG. 4. A common rail 43 and a fuel filter 44 are disposed on the intake manifold 3 installation side of the cylinder head 2, and a fuel pump 42 is disposed on the cylinder block 5 below the intake manifold 3. Each injector has an electromagnetic switching control type fuel injection valve (not shown).

  While the fuel in the fuel tank 45 is sucked into the fuel pump 42 via the fuel filter 44, the common rail 43 is connected to the discharge side of the fuel pump 42, and the cylindrical common rail 43 is connected to each injector of the diesel engine 1. Has been. The surplus of the fuel pumped from the fuel pump 42 to the common rail 43 is returned to the fuel tank 45, high-pressure fuel is temporarily stored in the common rail 43, and the high-pressure fuel in the common rail 43 is used for each diesel engine 1. Supplied inside the cylinder.

  With the above configuration, the fuel in the fuel tank 45 is pumped to the common rail 43 by the fuel pump 42, the high-pressure fuel is stored in the common rail 43, and the fuel injection valves of the injectors are controlled to open and close. The high-pressure fuel in 43 is injected into each cylinder of the diesel engine 1. That is, by electronically controlling the fuel injection valve of each injector, the fuel injection pressure, injection timing, and injection period (injection amount) can be controlled with high accuracy. Therefore, nitrogen oxides (NOx) discharged from the diesel engine 1 can be reduced.

  Next, a tractor 51 equipped with the diesel engine 1 will be described with reference to FIGS. A tractor 51 as a work vehicle shown in FIG. 4 to FIG. 9 is configured to perform a tilling work or the like for plowing a farm field by mounting a tillage working machine or the like (not shown). 4 is a side view of the agricultural tractor, FIG. 5 is a plan view thereof, FIG. 6 is a left side view of the engine portion, FIG. 7 is a right side view of the same portion, FIG. 8 is a plan view of the same portion, and FIG. 8 is an enlarged plan view of FIG. In the following description, the left side in the forward direction of the tractor is simply referred to as the left side, and the right side in the forward direction is also simply referred to as the right side.

  As shown in FIGS. 4 and 5, a farm tractor 51 as a work vehicle supports a traveling machine body 52 with a pair of left and right front wheels 53 and a pair of left and right rear wheels 54. The engine 1 is mounted, and the diesel engine 1 is configured to travel forward and backward by driving the rear wheel 54 and the front wheel 53. The upper surface side and the left and right side surfaces of the diesel engine 1 are covered with an openable / closable bonnet 56.

  Further, a cabin 57 on which an operator is boarded is installed behind the hood 56 in the upper surface of the traveling machine body 52. Inside the cabin 57, a steering seat 58 on which an operator is seated and steering equipment such as a steering handle 59 as steering means are provided. Further, a pair of left and right steps 60 for the operator to get on and off are provided in the left and right outer portions of the cabin 57, and fuel is supplied to the diesel engine 1 inside the step 60 and below the bottom portion of the cabin 57. A fuel tank 45 to be supplied is provided.

  The traveling machine body 52 includes a transmission case 61 for shifting the output from the diesel engine 1 and transmitting it to the rear wheel 54 (front wheel 53). A tiller working machine (not shown) is connected to the rear portion of the mission case 61 via a lower link 62, a top link 63, a lift arm 64, and the like so as to be movable up and down. Further, a PTO shaft 65 for driving the tilling work machine and the like is provided on the rear side surface of the mission case 61. The traveling machine body 52 of the tractor 51 includes the diesel engine 1, a transmission case 61, a clutch case 66 that connects them, and the like.

  Further, as shown in FIGS. 4 to 7, the DPF inlet pipe 34 is detachably bolted to the exhaust gas outlet pipe 80 of the supercharger 38. In addition, the upper end side of the DPF support leg 81 is welded and fixed to the outer peripheral surface of the end portion on the DPF outlet pipe 35 side in the outer peripheral surface of the first case 28, and on the side surface of the cylinder head 2 or the upper surface of the exhaust manifold 6. The bolt 82 is fastened to the lower end side of the DPF support leg 81 so as to be detachable. That is, the first case 28 is attached to the upper surface side of the diesel engine 1 through the exhaust gas outlet pipe 80 and the DPF support leg 81. The first case 28 is supported in parallel with the exhaust manifold 6 with the longitudinal direction of the cylindrical first case 28 facing the longitudinal direction of the diesel engine 1.

  As shown in FIGS. 6 to 9, an SCR first support leg 83 that supports the second case 29 and an SCR second support leg 84 are provided on the upper surface side of the diesel engine 1. The flange portion of the second case 29 is detachably bolted to the upper ends of the SCR first support leg 83 and the SCR second support leg 84, and the SCR is attached to the side surface of the cylinder head 2 or the upper surface of the intake manifold 3. The lower ends of the first support leg 83 and the SCR second support leg 84 are detachably bolted. Accordingly, the first case 28 and the second case 29 are arranged in parallel in the front-rear direction on the upper surface side of the diesel engine 1, and the first case 28 is located on the left side of the upper surface of the diesel engine 1, and the upper surface of the diesel engine 1. The second case 29 is located on the right side of the.

  In addition, a urea mixing tube 39 is disposed between the first case 28 and the second case 29 in parallel therewith. The first case 28, the second case 29, and the urea mixing pipe 39 are supported at a position higher than the cooling air path of the cooling fan 24, and the left and right sides of the urea mixing pipe 39 are the first case 28 and the second case. It is closed at 29. The temperature of the exhaust gas in the urea mixing pipe 39 is prevented from decreasing, and urea water supplied into the urea mixing pipe 39 is prevented from crystallizing. Further, the urea water supplied into the urea mixing pipe 39 is configured to be mixed as ammonia in the exhaust gas from the first case 28 to the second case 29.

  As shown in FIGS. 4 to 9, a tail pipe 91 is erected on the front surface of the right corner of the cabin 57 of the front surface of the cabin 57, and a lower end side of the tail pipe 91 is extended inside the bonnet 56, so that the SCR outlet The lower end side of the tail pipe 91 is connected to the pipe 37, and the exhaust gas hatched in the second case 29 is discharged from the tail pipe 91 toward the upper side of the cabin 57. A urea water tank 71 is installed on the left side of the bonnet 56 on the opposite side of the front side of the cabin 57 from the right side where the tail pipe 91 is disposed. That is, the tail pipe 91 is disposed on the right side of the rear part of the bonnet 56, and the urea water tank 71 is disposed on the left side of the rear part of the bonnet 56.

  Further, a urea water tank 71 is mounted on the traveling machine body 52 (such as the bottom frame of the cabin 57) on the rear left side of the bonnet 56. An oil filling port 46 of the fuel tank 45 and a water filling port 72 of the urea water tank 71 are provided adjacent to each other at the lower front portion on the left side of the cabin 57. The tail pipe 91 is disposed on the front surface on the right side of the cabin 57 where the operator's boarding / alighting frequency is low, and the oil inlet 46 and the water inlet 72 are disposed on the front surface on the left side of the cabin 57 where the operator's boarding / alighting frequency is high. The cabin 57 is configured so that the operator can get on and off the control seat 58 from either the left side or the right side.

  Further, a urea water injection pump 73 that pumps the urea aqueous solution in the urea water tank 71, an electric motor 74 that drives the urea water injection pump 73, and urea that is connected to the urea water injection pump 73 via a urea water injection pipe 75. A water injection nozzle 76 is provided. A urea water injection nozzle 76 is attached to the urea mixing pipe 39 via an injection base 77, and the urea aqueous solution is sprayed from the urea water injection nozzle 76 into the urea mixing pipe 39.

  With the above configuration, carbon monoxide (CO) and hydrocarbons (HC) in the exhaust gas of the diesel engine 1 are reduced by the oxidation catalyst 30 and the soot filter 31 in the first case 28. Next, urea water from the urea water injection nozzle 7 is mixed with the exhaust gas from the diesel engine 1 inside the urea mixing pipe 39. Then, the SCR catalyst 32 and the oxidation catalyst 33 in the second case 29 reduce nitrogen oxides (NOx) in the exhaust gas mixed with urea water as ammonia, and are released from the tail pipe 91 to the outside of the machine. .

  As shown in FIGS. 1 to 9, a first case 28 for removing particulate matter in the exhaust gas of the diesel engine 1 and a second case 29 for removing nitrogen oxides in the exhaust gas of the diesel engine 1 are provided. In an engine device of a work vehicle in which the diesel engine 1 is mounted on a machine body frame (travel machine body 52) in which left and right traveling wheels (front wheels 53, rear wheels 54) are arranged, in a direction parallel to the output shaft core line of the diesel engine 1 The first case 28 and the second case 29 are arranged. Therefore, the first case 28 and the second case 29 are utilized by utilizing the upper surface side or the side surface of the diesel engine 1 so that the longitudinal directions of the first case 28 and the second case 29 are parallel to the output shaft 4 of the diesel engine 1. 29 can be installed compactly. Further, the first case 28 and the second case 29 can be fixed to the upper surface side or side surface of the diesel engine 1 with high rigidity by a simple support structure provided on the upper surface side or side surface of the diesel engine 1. In addition, with respect to vibration of the diesel engine 1, the case 28, 29 can be maintained at a fixed interval between the first case 28 and the second case 29 and the outer shape is formed in a long cylindrical shape. Further, the exhaust gas piping between the exhaust gas outlet side of the diesel engine 1 and the tail pipe 91 can be simplified.

  As shown in FIGS. 1 to 9, a first case 28 is attached above the exhaust manifold 6 of the diesel engine 1 on the upper surface side of the diesel engine 1, and a second case 29 is located above the intake manifold 3 of the diesel engine 1. Is installed. Therefore, the upper surface side space of the diesel engine 1 can be effectively utilized, and the first case 28 and the second case 29 that are formed in a long cylindrical shape can be installed in a compact manner. In addition, the first case 28 and the second case 29 can be fixed to the upper surface side of the diesel engine 1 with high rigidity by a simple support structure that stands on the upper surface side of the diesel engine 1.

  As shown in FIGS. 4 to 9, it is a work vehicle in which a driving cabin 57 is arranged behind a hood 56 in which the diesel engine 1 is installed, and a fuel tank 45 provided in a lower portion of the driving cabin 57 and the diesel engine 1. A urea water tank 71 for exhaust gas purification is installed between them. Therefore, the urea water tank 71 can be heated by the exhaust heat of the diesel engine 1 and the fuel tank 45, the temperature of the aqueous solution in the urea water tank 71 can be maintained at a predetermined level or more, and the exhaust gas purification of the second case 29 can be performed in cold regions. It is possible to prevent the ability from decreasing. The fuel supply port of the fuel tank 45 and the water supply port of the urea water tank 71 can be disposed close to each other, the fuel supply work and the urea aqueous solution water supply work can be executed at the same work place, and the fuel or exhaust gas purification for the diesel engine 1 is performed. This makes it possible to improve the replenishment workability of the aqueous urea solution.

  Next, as shown in FIG. 10, the pipe bracket 40 that connects the SCR inlet pipe 36 and the urea mixing pipe 39 includes an inlet flange 92 that is welded and fixed to the exhaust gas inlet side of the SCR inlet pipe 36, and the exhaust gas from the urea mixing pipe 39. It has an outlet side flange 93 that is welded to the gas outlet side. A ring-shaped inlet flange 92 is fixed to the exhaust gas inlet side end portions of the outer tube 86 and the inner tube 87 of the SCR inlet tube 36 having a double tube structure, and similarly, the urea mixing tube 39 having a double tube structure is also provided. A ring-shaped outlet side flange 93 is fixed to the exhaust gas outlet side ends of the outer pipe 88 and the inner pipe 89. The inlet side flange 92 and the outlet side flange 93 are fastened and fixed by bolts 94 and nuts 95, and the SCR inlet pipe 36 and the urea mixing pipe 39 are connected.

  Further, as shown in FIG. 10, the outer tube 86 of the SCR inlet tube 36 and the outer tube 88 of the urea mixing tube 39 are formed of the same diameter pipe, and the inner tube 87 of the SCR inlet tube 36 and the urea mixing tube 39. The inner pipe 89 is also formed of a pipe having the same diameter. The pipe thickness of each inner pipe 87, 89 is made thinner than the pipe thickness of each outer pipe 86, 88. Further, a fitting small-diameter portion 89 a is formed at the end of the inner tube 89 of the urea mixing tube 39 by drawing, and the fitting small-diameter portion 89 a is inserted into the inner tube 87 of the SCR inlet tube 36. The end portion of the inner tube 87 of the SCR inlet tube 36 to which the inlet side flange 92 is fixed is fitted to the end portion (the fitting small diameter portion 89a) of the inner tube 89 of the urea mixing tube 39 to which the outlet side flange 93 is fixed. Let

  That is, the exhaust gas in the urea mixing pipe 39 is configured to move to the SCR inlet pipe 36 without contacting the inner hole surface of the inlet side flange 92 or the outlet side flange 93. When exhaust gas comes into contact with the inner hole surface of the inlet side flange 92 or the outlet side flange 93, the temperature of the exhaust gas decreases, and the urea component in the exhaust gas crystallizes, and the inlet side flange 92 or the outlet side flange 93 And a crystal lump of urea component is formed on the inner hole surface of the inlet side flange 92 or the outlet side flange 93, and a defect that hinders the movement of exhaust gas is likely to occur. On the other hand, as shown in FIG. 10, the inner hole surface of the inlet side flange 92 or the outlet side flange 93 is shielded by the small diameter portion 89a of the inlet side flange 92 or the outlet side flange 93. The exhaust gas is prevented from coming into contact with the exhaust gas, and the formation of a urea component crystal lump on the inner hole surface of the inlet side flange 92 or the outlet side flange 93 is prevented.

  Next, the structure of the SCR inlet pipe 36 of the second case 29 will be described with reference to FIGS. 11 and 12. As shown in FIGS. 11 and 12, the elbow tubular outer tube 86 constituting the SCR inlet tube 36 has a pair of half-cracked cylinders 86a obtained by dividing the cylinder into two in the longitudinal direction, and the pair of half-cracked cylinders 86a. The end portion in the longitudinal direction is bent outward to form a joint flange portion 86b at the portion. Similarly, an elbow tubular inner tube 87 constituting the SCR inlet tube 36 has a pair of half-cracked cylinders 87a obtained by dividing the cylinder into two in the longitudinal direction, and ends of the pair of half-cracked cylinders 87a in the longitudinal direction. Is bent outward to form a joint flange portion 87b at the portion. In a state where the joint flange portions 87b of the pair of half cracked cylinders 87a are welded and fixed to each other, the joint flange portions 87b are sandwiched and fixed by welding with the joint flange portions 86b of the pair of half cracked cylinders 86a. The tube 86 and the inner tube 87 are integrally formed.

  Further, both end sides of the inner tube 87 are protruded from the cylindrical openings at both ends of the elbow tubular outer tube 86, and the inlet side flange 92 is welded and fixed to one end opening edge of the outer tube 86 and the inner tube 87. On the other hand, one end side of the cylindrical inlet side inner tube 96 is welded and fixed to the other end side opening edge of the inner tube 87, and then one end side of the cylindrical inlet side outer tube 97 is connected to the other end side opening edge of the outer tube 86. The welding is fixed. The other end of the inlet side outer tube 97 is inserted into the inlet opening 98 of the second case 29 and fixed by welding, and the exhaust gas supply chamber of the second case 29 is opened from the other end side opening of the inlet side outer tube 97. The other end side of the inlet side inner pipe 96 is projected toward the inside 99.

  Further, the exhaust gas supply chamber 99 of the second case 29 is formed between the exhaust gas receiving end surface of the SCR catalyst 32 and the side lid body 100 in which the surface facing the SCR catalyst 32 is recessed in a concave shape. An exhaust gas in which urea water is mixed as ammonia is introduced into the exhaust gas supply chamber 99 from the other end side of the inlet-side inner pipe 96, and the exhaust gas is allowed to pass through the SCR catalyst 32 and the oxidation catalyst 33 so that the exhaust gas is contained in the exhaust gas. The nitrogen oxides (NOx) are reduced.

  Next, the structure of the urea mixing tube 39 will be described with reference to FIGS. As shown in FIGS. 9 and 13, the urea mixing pipe 39 includes an elbow pipe portion 39 a connected to the bellows-like connecting pipe 41 and a long cylindrical straight pipe connected to the SCR inlet pipe 36 via the pipe bracket 40. It has a part 39b. The injection base 77 is welded and fixed to the elbow pipe part 39a in the vicinity where the elbow pipe part 39a and the straight pipe part 39b are joined, and the urea water injection nozzle 76 is opened from the elbow pipe part 39a toward the inner hole of the straight pipe part 39b. Let

  Further, as shown in FIG. 13, the urea water injection direction 112 of the urea water injection nozzle 76 is set with respect to the cylindrical axis 111 of the cylindrical straight pipe portion 39b (the exhaust gas flow direction in the straight pipe portion 39b). The elbow pipe portion 39a is inclined to the lower side of the exhaust gas by a predetermined inclination angle 113 (about 4 degrees). That is, urea water is injected from the urea water injection nozzle 76 toward the inner wall surface 114a on the curved inner diameter side of the elbow pipe portion 39a in the inner wall surface 114 of the straight pipe portion 39b. The urea water injected from the urea water injection nozzle 76 is out of the curvature of the elbow pipe portion 39a in the inner wall surface 114 of the straight pipe portion 39b due to the discharge pressure of the exhaust gas moving from the elbow pipe portion 39a to the straight pipe portion 39b. It diffuses toward the inner wall surface 114b on the radial side and is mixed as ammonia in the exhaust gas.

  The inclination angle 113 (urea water injection direction 112) of the urea water injection nozzle 76 with respect to the cylindrical axis 111 of the straight pipe portion 39b is the inner diameter of the elbow pipe portion 39a and the straight pipe portion 39b, or standard work (diesel engine 1). The operation is performed based on the exhaust gas flow velocity at the rated rotation of the engine). For example, when the inclination angle 113 is excessive, urea water adheres to the inner wall surface 114a on the curved inner diameter side of the elbow pipe portion 39a, and urea tends to crystallize on the inner wall surface 114a on the curved inner diameter side. Further, when the inclination angle 113 is too small, urea water adheres to the inner wall surface 114b on the curved outer diameter side of the elbow pipe portion 39a, and urea tends to crystallize on the inner wall surface 114b portion on the curved outer diameter side.

  Next, an arrangement structure of the first case 28 and the second case 29 of the second embodiment will be described with reference to FIG. As shown in FIG. 15, the first case 28 is attached to the upper surface side of the diesel engine 1, and the side of the diesel engine 1 on which the intake manifold 3, the exhaust gas recirculation device 15, the fuel filter 44, and the like are installed. The second case 29 is attached to the traveling machine body 52. That is, the second case 29 is attached to the traveling body 52 at the lower right side of the diesel engine 1, the second case 29 is disposed between the right front surface of the cabin 57 and the right front wheel 53, and urea mixing is performed above the diesel engine 1. A pipe 39 is extended in a transverse shape, and a tail pipe 91 is connected to the rear end side of the second case 29.

  As shown in FIG. 15, the first case 28 is attached to the upper surface side of the diesel engine 1, and the second case 29 is attached to the side of the diesel engine 1 where the intake manifold 3 is installed. Accordingly, the tail pipe 91 connected to the exhaust gas outlet side of the second case 29 and the second case 29 are brought close to each other on the side of the airframe (the right side of the airframe) on the side where the operator gets in and out of the tractor 51 or the like. Can be arranged compactly. Further, the fuel tank 45 for the diesel engine 1 or the exhaust gas purifying is disposed on the other side of the airframe where the operator gets on and off frequently (the left side of the airframe away from the high temperature portion such as the tail pipe). The urea water tank 71 or the like can be provided to improve the replenishment workability of the fuel for the diesel engine 1 or the urea aqueous solution for exhaust gas purification.

  Next, an arrangement structure of the first case 28 and the second case 29 of the third to fourth embodiments will be described with reference to FIGS. 16 and 17. In the third embodiment shown in FIG. 16, the second case 29 is disposed above the first case 28 on the side where the exhaust manifold 6 of the diesel engine 1 is installed. The first case 28 and the second case 29 are offset from the side of the diesel engine 1 on the left side opposite to the side where the intake manifold 3, exhaust gas recirculation device 15 and fuel filter 44 are installed. In addition, the second case 29 on the low temperature side (lower exhaust side), the urea mixing tube 39, and the like can be supported above the first case 28 on the high temperature side (upper exhaust side). 29 and the urea mixing pipe 39 can be reduced in temperature, and the exhaust gas purification function can be properly maintained.

  On the other hand, in the fourth embodiment shown in FIG. 17, the second case 29 is arranged below the first case 28 on the side where the exhaust manifold 6 of the diesel engine 1 is installed. Below the first case 28 on the high temperature side (upper exhaust side) connected to the exhaust manifold 6, the second case 29 on the low temperature side (lower exhaust side), the urea mixing pipe 39 and the like can be supported. The second case 29 can be attached close to the fuel tank 45 or the urea water tank 71 to be mounted, and the bonnet height required for installing the first case 28 and the second case 29 can be formed low.

  Further, as shown in FIGS. 16 and 17, when the second case 29 is arranged on the upper side or the lower side of the first case 28 on the side where the exhaust manifold 6 of the diesel engine 1 is installed, the exhaust of the diesel engine 1. The first case 28 and the second case 29 can be placed close to each other on the manifold 6 side in a compact manner. With the exhaust heat on the exhaust manifold 6 side of the diesel engine 1, the temperature of the first case 28 or the second case 29 can be easily maintained at the temperature required for exhaust gas purification.

  Next, an arrangement structure of the first case 28 and the second case 29 of the fifth embodiment will be described with reference to FIGS. In the first embodiment, the exhaust gas movement direction of the first case 28 and the second case 29 is on the upper surface side of the diesel engine 1 so that it is parallel to the output shaft 4 (crankshaft) axis of the diesel engine 1. Whereas the first case 28 and the second case 29 are arranged, in the fifth embodiment, the exhaust gas moving direction of the first case 28 and the second case 29 is the output shaft 4 (crankshaft) shaft of the diesel engine 1. A first case 28 and a second case 29 are arranged on the upper surface side of the diesel engine 1 so as to be orthogonal to the core wire.

  A fifth embodiment will be described with reference to the drawings. 18 is a right side view where an intake manifold of a diesel engine is installed, FIG. 19 is a left side view where an exhaust manifold of the diesel engine is installed, FIG. 20 is a plan view thereof, and FIG. 21 is a cooling fan of the diesel engine. 22 is a rear view in which a flywheel of a diesel engine is installed, and FIGS. 23 and 24 are perspective views of the diesel engine. The overall structure of the diesel engine 1 will be described with reference to FIGS.

  As shown in FIGS. 18 to 24, an intake manifold 3 is disposed on one side surface of the cylinder head 2 of the diesel engine 1. The cylinder head 2 is mounted on a cylinder block 5 in which an engine output shaft 4 (crankshaft) and a piston (not shown) are built. An exhaust manifold 6 is disposed on the other side of the cylinder head 2. The front end and the rear end of the engine output shaft 4 are projected from the front and rear surfaces of the cylinder block 5.

  A flywheel housing 8 is fixed to the rear surface of the cylinder block 5. A flywheel 9 is provided in the flywheel housing 8. A flywheel 9 is pivotally supported on the rear end side of the engine output shaft 4. The power of the diesel engine 1 is taken out via the flywheel 9. Further, an oil pan 11 is disposed on the lower surface of the cylinder block 5.

  As shown in FIGS. 18 and 20, an exhaust gas recirculation device (EGR) 15 that takes in exhaust gas for recirculation is arranged in the intake manifold 3. An air cleaner 16 is connected to the intake manifold 3. The external air that has been dedusted and purified by the air cleaner 16 is sent to the intake manifold 3 and supplied to each cylinder of the diesel engine 1.

  With the above configuration, a part of the exhaust gas discharged from the diesel engine 1 to the exhaust manifold 6 is recirculated from the intake manifold 3 to each cylinder of the diesel engine 1 via the exhaust gas recirculation device 15. The combustion temperature of the diesel engine 1 is lowered, the emission amount of nitrogen oxide (NOx) from the diesel engine 1 is reduced, and the fuel efficiency of the diesel engine 1 is improved.

  A cooling water pump 21 that circulates cooling water in the cylinder block 5 and the radiator 19 is disposed on the cooling fan 24 installation side of the diesel engine 1. The cooling water pump 21 and the cooling fan 24 are connected to the engine output shaft 4 via the V belt 22 and the like, and the cooling water pump 21 and the cooling fan 24 are driven. While the cooling water is sent from the cooling water pump 21 into the cylinder block 5, the diesel engine 1 is cooled by the cooling fan 24 wind.

  As shown in FIGS. 18 to 24, as an exhaust gas purifying device 27 for purifying exhaust gas discharged from each cylinder of the diesel engine 1, diesel particulates that remove particulate matter in the exhaust gas of the diesel engine 1 are used. A first case 28 as a curate 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. 20, an oxidation catalyst 30 and a 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. A DPF inlet pipe 34 for taking in exhaust gas and a DPF outlet pipe 35 for discharging exhaust gas are provided on both cylindrical sides of the first case 28 (one end side and the other end side in the exhaust gas movement direction). Similarly, an SCR inlet pipe 36 for taking in the exhaust gas and an SCR outlet pipe 37 for discharging the exhaust gas are provided on both cylindrical sides of the second case 29 (one end side and the other end side in the exhaust gas moving direction). Yes.

  Further, a supercharger 38 that forcibly sends air to the diesel engine 1 is disposed at the exhaust gas outlet of the exhaust manifold 6. The DPF inlet pipe 34 communicates 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 DPF outlet pipe 35 enters the SCR inlet via the urea mixing pipe 39. The pipe 36 is connected, and the exhaust gas of the first case 28 is introduced into the second case 29. The exhaust gas outlet side of the end of the urea mixing pipe 39 is detachably connected to the SCR inlet pipe 36 via the pipe bracket 40.

  As shown in FIG. 18, a fuel pump 42 and a common rail 43 that connect a fuel tank 45 are provided to injectors (not shown) for multiple cylinders of the diesel engine 1. A common rail 43 and a fuel filter 44 are disposed on the intake manifold 3 installation side of the cylinder head 2, and a fuel pump 42 is disposed on the cylinder block 5 below the intake manifold 3. Each injector has an electromagnetic switching control type fuel injection valve (not shown).

  While the fuel in the fuel tank 45 is sucked into the fuel pump 42 via the fuel filter 44, the common rail 43 is connected to the discharge side of the fuel pump 42, and the cylindrical common rail 43 is connected to each injector of the diesel engine 1. It is connected.

  With the above configuration, the fuel in the fuel tank 45 is pumped to the common rail 43 by the fuel pump 42, high-pressure fuel is stored in the common rail 43, and the fuel injection valves of the injectors are controlled to open and close. The high-pressure fuel inside is injected into each cylinder of the diesel engine 1. That is, by electronically controlling the fuel injection valve of each injector, the fuel injection pressure, injection timing, and injection period (injection amount) can be controlled with high accuracy. Therefore, nitrogen oxides (NOx) discharged from the diesel engine 1 can be reduced.

  Next, with reference to FIG. 25 and FIG. 26, the tractor 51 of 5th Embodiment carrying the diesel engine 1 shown in FIGS. 18-24 is demonstrated. Similar to the first embodiment shown in FIGS. 4 and 5, the tractor 51 of the fifth embodiment as a work vehicle includes a pair of left and right front wheels 53 and a pair of left and right front wheels 53 as shown in FIGS. 25 and 26. The diesel engine 1 is mounted on the front part of the traveling machine body 52, and the rear wheel 54 and the front wheel 53 are driven by the diesel engine 1 so as to travel forward and backward. Yes. The upper surface side and the left and right side surfaces of the diesel engine 1 are covered with an openable / closable bonnet 56.

  On the other hand, a cabin 57 on which an operator is boarded is installed behind the hood 56 in the upper surface of the traveling machine body 52. Inside the cabin 57, a steering seat 58 on which an operator is seated and steering equipment such as a steering handle 59 as steering means are provided. Further, a pair of left and right steps 60 for the operator to get on and off are provided in the left and right outer portions of the cabin 57, and fuel is supplied to the diesel engine 1 inside the step 60 and below the bottom portion of the cabin 57. A fuel tank 45 to be supplied is provided.

  Further, the traveling machine body 52 includes a transmission case 61 for shifting the output from the diesel engine 1 and transmitting it to the rear wheel 54 (front wheel 53). A tiller working machine (not shown) is connected to the rear portion of the mission case 61 via a lower link 62, a top link 63, a lift arm 64, and the like so as to be movable up and down. Further, a PTO shaft 65 for driving the tilling work machine and the like is provided on the rear side surface of the mission case 61. The traveling machine body 52 of the tractor 51 includes the diesel engine 1, a transmission case 61, a clutch case 66 that connects them, and the like.

    The exhaust gas exhaust structure of the diesel engine 1 will be described with reference to FIGS. 1, 3, 8, and 11. As shown in FIGS. 1, 3, and 11, one end of a flexible heat-resistant rubber gas discharge pipe 171 is connected to the exhaust gas outlet pipe 80 of the supercharger 38, and the gas discharge pipe 171 is connected to the DPF inlet pipe 34. The other end side of the exhaust manifold 6 is connected, the first case 28 is communicated with the supercharger 38 via the gas discharge pipe 171, and the exhaust gas of the exhaust manifold 6 is moved from the supercharger 38 to the first case 28. doing.

  Further, one end side of a metal bellows-like connecting pipe 41 is connected to the DPF outlet pipe 35, and the other end side of the bellows-like connecting pipe 41 is connected to the exhaust gas inlet side of the urea mixing pipe 39 (the elbow pipe in FIGS. 13 and 20). Part 39a) is integrally disposed, and the DPF outlet pipe 35 is connected to one end side of the urea mixing pipe 39 via the bellows-like connecting pipe 41, and the exhaust gas outlet side of the urea mixing pipe 39 (FIGS. 13 and 20). The SCR inlet pipe 36 is connected via a pipe bracket 40 to the straight pipe portion 39b). That is, the SCR inlet pipe 36 is connected to the DPF outlet pipe 35 via the bellows-like connecting pipe 41 and the urea mixing pipe 39, the second case 29 is connected to the first case 28, and the second case 29 is connected to the second case 29. The case 29 is configured to move the exhaust gas. The bellows-like connecting pipe 41 is formed in a bellows shape so as to be foldable and extendable. When the first case 28 and the second case 29 are assembled, the bellows-like connecting pipe 41 is deformed to form the first bellows-like connecting pipe 41. An assembly dimension error between the case 28 and the second case 29 is corrected.

  As shown in FIGS. 18, 25, and 26, the urea water tank 71 that stores urea water, the urea water injection nozzle 76 for supplying urea, and the urea water in the urea water tank 71 are pumped to the urea water injection nozzle 76. A urea water injection pump 73 is provided. As in the first embodiment shown in FIGS. 4 and 5, the urea water tank 71 is installed in the traveling machine body 52 between the diesel engine 1 and the fuel tank 45. The urea water injection pump 73 is driven by the output of the electric motor 74. The urea water injection nozzle 76 is disposed on the injection base 77 of the urea mixing tube 39.

  With the above configuration, the urea water in the urea water tank 71 is pumped from the urea water injection pump 73 to the urea water injection nozzle 76, the urea water is injected from the urea water injection nozzle 76 into the urea mixing pipe 39, and the urea mixing pipe The urea water from the urea water injection nozzle 7 is mixed with the exhaust gas from the diesel engine 1 inside 39. The exhaust gas mixed with urea water passes through the second case 29 (SCR catalyst 32, oxidation catalyst 33), nitrogen oxides (NOx) in the exhaust gas are reduced, and discharged from the SCR outlet pipe 37 to the outside. The By spraying urea water into the exhaust gas, ammonia gas is generated in the exhaust gas by hydrolysis, and the ammonia gas and the exhaust gas are mixed and introduced into the second case 29 from the SCR inlet pipe 36. Then, nitrogen oxides (NOx) in the exhaust gas are removed by the catalysts 32 and 33 in the second case 29.

  Next, with reference to FIGS. 18-24, the attachment structure of the exhaust-gas purification apparatus 27 is demonstrated. A first support leg 181 that supports the DPF inlet pipe 34 side of the first case 28 and a second support leg 182 that supports the DPF outlet pipe 35 side of the first case 28 are provided. The lower end side of the first support leg 181 is fastened to the side face of the cylinder head 2 on the exhaust manifold 6 arrangement side, and the first support leg 181 is erected on one side face of the cylinder head 2. The DPF inlet pipe 34 side of the first case 28 is detachably fixed to the upper end side of the first support leg 181 with a fastening band 186.

  Further, the lower end side of the second support leg 182 is fastened to the side surface of the cylinder head 2 on the side of the intake manifold 3 arrangement side and the side of the cooling water pump 21 arrangement side, and bolts 184 and 185 are fastened. A second support leg 182 is erected on the other side. The DPF outlet pipe 35 side of the first case 28 is detachably fixed to the upper end side of the second support leg 182 with a fastening bolt 187. That is, the first support leg 181 and the second support leg 182 are erected on the opposing 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, as shown in FIGS. 18 and 19, a radiator 19 disposed to face the cooling fan 24 is provided. A body frame 191 is erected on the upper surface side of the traveling body 52. The body frame 191 supports the radiator 19 and the wind tunnel plate 192. The cooling fan 24 is covered by the wind tunnel plate 192, and the cooling fan 24 sucks outside air through the radiator 19, and supplies cooling air from the cooling fan 24 to the diesel engine 1 by the guidance of the wind tunnel plate 192. Cooling water is circulated by the cooling water pump 21 to each part of the diesel engine 1 and the radiator 19 to cool the diesel engine 1.

  As shown in FIGS. 18 and 19, the SCR support leg 193 protrudes from the second case 29 toward the lower surface, and the lower end side of the SCR support leg 193 is detachably fastened to the machine body frame 191. doing. A second case 29 is disposed substantially immediately above the cooling fan 24. A wind tunnel plate 192 as a shroud is interposed between the upper surface side of the cooling fan 24 and the lower surface side of the second case 29. The upper ends of the first support leg 181 and the second support leg 182 are provided at a higher position than the uppermost end of the wind tunnel plate 192, and the first case 28 is positioned higher than the uppermost end of the wind tunnel plate 192. The second case 29 is supported at a higher position than the first case 28 via the body frame 191 and the SCR support leg 193.

  The first case 28 and the first case 28 so that the exhaust gas moving directions (cylindrical axis) of the first case 28 and the second case 29 are orthogonal to the output shaft 4 of the diesel engine 1 extending in the front-rear direction. The second case 29 is extended in the left-right direction. Of the upper surface side of the diesel engine 1, the first case 28 and the second case 29 are arranged in parallel on the upper surface side of the cooling fan 24 installation portion, and urea is disposed above the opposing side surface of the first case 28 and the second case 29. Mixing tubes 39 are extended in parallel. Further, the first case 28 and the second case 29 are arranged at a higher position than the cooling fan 24 air passage of the diesel engine 1 formed by the wind tunnel plate 192, and the first case 28 and the second case 29 are arranged at a higher position than the first case 28. Two cases 29 are arranged. That is, the first case 28 and the second case 29 are disposed at a position higher than the upper surface of the wind tunnel plate 192 (cooling fan shroud) of the diesel engine 1, and the second case 29 is disposed immediately above the cooling fan 24.

  Therefore, the cooling air from the cooling fan 24 is moved and guided to the upper surface side of the diesel engine 1 by the engine cooling air guide action of the first support leg 181 and the second support leg 182 as case brackets. A cooling wind guide body (not shown) is provided between the first case 28 and the wind tunnel plate body 92, and the cooling wind guide body is guided from the wind tunnel plate body 192 side toward the upper surface side of the diesel engine 1. The cooling air from the cooling fan 24 can also be moved.

  As shown in the first embodiment (FIGS. 1 to 14) and the fifth embodiment (FIGS. 18 to 24), the first case 28 for removing particulate matter in the exhaust gas of the diesel engine 1, and the diesel engine 1. A second case 29 for removing nitrogen oxides in the exhaust gas, and a urea mixing pipe 39 for connecting the exhaust gas outlet of the first case 28 to the exhaust gas inlet of the second case 29. In the exhaust gas purifying apparatus in which the two cases 29 are arranged in parallel and the urea water is injected into the urea mixing pipe 39, the first case 28, the second case 29, and the urea mixing pipe 39 are arranged in the exhaust gas moving direction. The DPF outlet pipe 35 as an exhaust gas outlet pipe is provided on the end face of the first case 28 on the exhaust gas outlet side, and the exhaust gas inlet is provided on the side surface of the second case 29 on the exhaust gas inlet side. Tube and The SCR inlet pipe 36 is provided, the DPF outlet pipe 35 is connected to the urea mixing pipe 39 via the bellows-like connecting pipe 41, and the urea water injection nozzle 76 is connected between the urea mixing pipe 39 and the bellows-like connecting pipe 41. It is arranged. Therefore, the assembly operation of the first case 28 and the assembly operation of the second case 29 are respectively performed on the diesel engine 1 or the vehicle (the traveling machine body 52), and the first case 28 and the second case 29 are separately performed. The urea mixing tube 39 can be connected to the first case 28 and the second case 29 via the bellows-like connecting pipe 41 in a state where the case 29 is assembled independently.

  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, by adjusting the mounting position of the deformable bellows-like connection pipe 41 (correcting the assembly dimension error), a support member (SCR first support leg 83, SCR, separate from the DPF support leg 81 of the first case 28). The second case 29 can be easily attached to the second support leg 84). Also, urea water injected from the urea water injection nozzle 76 is bellows-like by injecting urea water from the urea water injection nozzle 76 toward the urea mixing pipe 39 on the lower side of the exhaust gas movement of the bellows-shaped connecting pipe 41. It can prevent that it adheres to the inner surface of the connection pipe 41, and crystallizes.

  Further, as shown in the first embodiment (FIGS. 1 to 9, 13), the position of the DPF inlet pipe 34 is aligned with the exhaust gas outlet pipe 80, and the second case 29 is provided on the exhaust gas inlet side of the first case 28. The first case 28 and the second case 29 can be arranged within the front-rear width of the diesel engine 1 by being displaced. On the other hand, as shown in the first embodiment (FIG. 14) and the fifth embodiment (FIGS. 18 to 24), an exhaust gas outlet pipe 80 as an exhaust connection pipe for taking in the exhaust gas of the diesel engine 1 is provided. The first case 28 is connected to the side surface 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 bellows rather than the end surface of the first case 28 on the exhaust gas outlet side. The end face of the second case 29 on the exhaust gas outlet side protrudes by the installation width dimension L of the second connection pipe 41, and the bellows-like connection pipe 41 is arranged on the outer peripheral side of the second case 29 on the exhaust gas outlet side. You can also. 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 secured satisfactorily.

  Further, the second case 29 is displaced with respect to the first case 28 in the exhaust gas movement direction, and the difference between the lengths of the first case 28 and the second case 29 in the exhaust gas movement direction and the bellows-like connection The exhaust gas inlet side end surface of the second case 29 is positioned on the lower side of the exhaust gas movement with respect to the exhaust gas inlet side end surface of the first case 28 by the step size M of the mounting width generated by the installation width dimension L of the pipe 41. Deviate. Further, as described above, the exhaust gas outlet side end surface of the second case 29 is located on the lower side of the exhaust gas movement with respect to the exhaust gas outlet side end surface of the first case 28 by the installation width dimension L of the bellows-like connecting pipe 41. It is deviated. 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 tube 39 and the bellows-like connecting pipe 41 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 41 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 41 can be installed in the formed recess space, the temperature drop of the bellows-like connecting pipe 41 can be reduced, and the temperature of the exhaust gas from the first case 28 to the urea mixing pipe 39 It can be easily prevented from lowering when passing. Therefore, even if urea water flows backward into the bellows-like connection pipe 41, crystallization of urea water inside the bellows-like connection pipe 41 can be prevented.

1 Diesel Engine 3 Intake Manifold 4 Engine Output Shaft 6 Exhaust Manifold 28 First Case 29 Second Case 45 Fuel Tank 52 Traveling Airframe (Airframe Frame)
53 Front wheel (traveling wheel)
54 Rear wheel (traveling wheel)
56 Bonnet 57 Cabin 71 Urea water tank

Claims (2)

A first case as a diesel particulate filter for removing particulate matter in engine exhaust gas, a second case as a urea selective reduction catalyst system for removing nitrogen oxides in the engine exhaust gas, and the second case In an engine device for a work vehicle, which includes a urea mixing pipe that connects one case and the second case, and the engine is mounted on a body frame in which left and right traveling wheels are arranged.
The engine is arranged between the first case and the urea mixing tube and the second case to the output shaft core direction parallel to, attaching the first case on the upper side of the engine, exhaust gas in the first case A DPF outlet pipe is provided on an end face on the outlet side, an SCR inlet pipe is provided at a position near the exhaust gas inlet on the longitudinal outer peripheral surface of the second case, and the DPF outlet pipe and the SCR inlet pipe are interposed via the urea mixing pipe. And a urea water injection nozzle is attached to the upstream side of the urea mixing pipe,
Engine device for work vehicle. A working vehicle having a driving cabin disposed behind a hood in which the engine is installed, wherein a urea water tank for exhaust gas purification is installed between a fuel tank provided at a lower portion of the driving cabin and the engine. ing,
An engine device for a work vehicle according to claim 1.

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