JP2009138680A - Exhaust emission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device provided with a filter (DPF) reducing particulate matter (PM) contained in exhaust gas and a catalyst tank storing a selective reduction type NOx catalyst (SCR) selectively reducing and eliminating NOx in exhaust gas under existence of urea water, which can be mounted on a vehicle even if the vehicle is a short vehicle. <P>SOLUTION: In the exhaust emission control device provided with the filter collecting particulate matter contained in the exhaust gas and the catalyst tank storing the selective reduction type NOx catalyst selectively reducing and eliminating NOx in exhaust gas under existence of urea water in an exhaust gas passage of an internal combustion engine loaded on a vehicle in an order from an upstream side of exhaust gas flow, the filter and the catalyst tank are mounted on a vehicle body respectively and are connected by piping, and the catalyst tank is provided below a vehicle component mounted on a chassis frame provided with extending in a longitudinal direction of the vehicle. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an exhaust emission control device, and in particular, traps particulate matter contained in exhaust gas in the exhaust passage of an internal combustion engine such as a diesel engine mounted on a vehicle in order from the upstream side of the exhaust flow. The present invention relates to an exhaust gas purification apparatus provided with a filter to collect and a catalyst tank containing a selective reduction type NOx catalyst that selectively reduces and purifies NOx in exhaust gas in the presence of urea water.

  In an internal combustion engine such as an automobile engine, particularly a diesel engine, air is compressed to a high pressure in a combustion chamber so as to have a high temperature, and fuel is injected to cause spontaneous ignition. It contains a large amount of particulate matter (hereinafter referred to as PM), nitrogen oxide (hereinafter referred to as NOx), and the like.

  2. Description of the Related Art Conventionally, as a purification device for reducing PM in this type of exhaust gas, an exhaust purification device in which a diesel particulate filter (hereinafter referred to as DPF) is provided in the exhaust passage of exhaust gas from a diesel engine is known. Yes. In such an exhaust purification device, PM in exhaust gas can be collected by DPF, and the amount of PM released into the atmosphere can be reduced.

  On the other hand, as a purification device for reducing NOx in exhaust gas, a selective catalytic reduction (hereinafter referred to as a selective catalytic reduction catalyst) that selectively reduces NOx in exhaust gas using urea water as a reducing agent in an exhaust gas exhaust passage of a diesel engine. 2. Description of the Related Art An exhaust gas purification device provided with an SCR) is known. In such an exhaust purification device, when urea water is added to the exhaust gas upstream of the SCR, the added urea water is heated and hydrolyzed by the heat of the exhaust gas to produce ammonia and carbon dioxide. This ammonia functions as a reducing agent that purifies NOx in the exhaust gas by SCR, and can reduce the amount of NOx released to the atmosphere.

In addition to the exhaust gas purification device provided with only one of the DPF and the SCR, an exhaust gas purification device provided with both the DPF and the SCR is also known. As an exhaust gas purification apparatus equipped with both such a DPF and an SCR, for example, Patent Document 1 discloses a pre-stage catalyst that generates NO ₂ by oxidizing NO in exhaust gas in the flow direction of exhaust gas from an internal combustion engine of a vehicle. An exhaust gas purification apparatus in which a DPF that collects PM in exhaust gas, an SCR that purifies NOx in exhaust gas by adding urea water, and a rear catalyst that oxidizes surplus NH ₃ to generate N ₂ are sequentially installed A first housing for housing the front catalyst and the DPF, a second housing for housing the SCR and the rear catalyst, and extending in the width direction of the vehicle, An exhaust emission control device is disclosed that includes a connecting pipe that connects a second housing and has a first housing and a second housing disposed with a vehicle frame in between.

JP 2007-40224 A

In recent years, in particular, reduction of PM and NOx in exhaust gas discharged from diesel engines has been demanded, and regulations tend to be stricter. For this reason, it is required to provide an exhaust purification device including both a DPF and an SCR, for example, in a short vehicle such as a dump truck, a mixer, and a garbage truck.
Therefore, it is conceivable to mount the exhaust purification device disclosed in Patent Document 1 on the short vehicle. However, the exhaust purification device disclosed in Patent Document 1 includes a first casing, a second casing, and the like. Positioning adjacent to the frame, although using a smaller space than arranging the first housing and the second housing together in one place by placing them apart from each other It is indispensable to secure a space for disposing the first housing and a space for disposing the second housing, respectively. Therefore, in a short vehicle having a short frame length, the first housing It is difficult to secure a space for mounting the body and the second housing. Therefore, it is difficult to mount the exhaust purification device disclosed in Patent Document 1 on a short vehicle.

  Therefore, in view of the problems of the prior art, the present invention reduces particulate matter (PM) contained in exhaust gas that can be mounted on a vehicle even in a short vehicle such as a dump truck, a mixer, and a garbage truck. An object of the present invention is to provide an exhaust emission control device provided with a filter (DPF) and a catalyst tank containing a selective reduction type NOx catalyst (SCR) that selectively reduces and purifies NOx in exhaust gas in the presence of urea water. .

In order to solve the above problems, in the present invention,
In the exhaust passage of the internal combustion engine mounted on the vehicle, in order from the upstream side of the exhaust flow, a filter that collects particulate matter contained in the exhaust gas and NOx in the exhaust in the presence of urea water are selected In the exhaust gas purification apparatus provided with a catalyst tank containing a selective reduction type NOx catalyst for reducing and purifying in an effective manner, the filter and the catalyst tank are respectively attached to a vehicle body and connected by piping, and the catalyst tank Is disposed below a vehicle part attached to a chassis frame extending in the front-rear direction of the vehicle.

By connecting the filter and the catalyst tank with a pipe, positions where the filter and the catalyst tank are disposed are dispersed, so that the mountability is improved.
In addition, by arranging the catalyst tank below the vehicle parts attached to the chassis frame that extends in the vehicle longitudinal direction, the layout can be greatly increased even when there is no space to install the catalyst tank on the chassis frame. The catalyst tank can be mounted without changing to the above, and it is possible to mount an exhaust purification device including both a DPF and an SCR even for a short vehicle or the like.
The catalyst tank is only required to be disposed on the lower side of the vehicle component. For example, the catalyst tank may be attached to the vehicle component directly or via a support member such as a bracket, and is disposed on the chassis frame or other neighborhood. It may be attached to the vehicle component directly or via a support member such as a bracket.

The catalyst tank may have an arcuate cross section at the top, and the vehicle parts may have a flat bottom surface and are coupled to each other in a line contact state.
In the catalyst tank, a reduction reaction occurs in which NOx in the exhaust gas is reduced, and the reduction reaction is an exothermic reaction, so that the temperature of the catalyst tank rises when the exhaust gas treatment is performed.
The upper part of the catalyst tank has an arc-shaped cross section, and the bottom surface of the vehicle part on which the catalyst tank is disposed on the lower side has a flat shape. Since they are coupled in contact, the increase in the catalyst tank temperature due to the exothermic reaction in the catalyst tank is not easily transmitted to the vehicle parts above the catalyst tank, and the temperature increase in the vehicle parts above the catalyst tank can be reduced. .
This is particularly effective when the vehicle part disposed on the upper side of the catalyst tank is a part for which it is desired to avoid the temperature rise.

  Further, the filter is disposed inside the chassis frame and the catalyst tank and the vehicle parts are disposed outside the chassis frame, and from the chassis frame in a pipe connecting the filter and the tank. Also, an injection device for injecting urea water is provided inside the vehicle, and the exhaust inlet portion of the catalyst tank is provided outside the vehicle from the exhaust outlet portion of the catalyst tank.

The exhaust gas from which particulate matter (PM) has been reduced by the filter (DPF) is introduced into the tank containing the SCR through a pipe connecting the filter and the tank. By injecting urea water into the pipe connecting the tank containing DPF and SCR, the urea water is hydrolyzed in the pipe by the heat of the exhaust gas as shown in the chemical formula (1), and ammonia (NH ₃ ) Carbon dioxide (CO ₂ ) is generated.
(NH ₂ ) ₂ CO + H ₂ O → 2NH ₃ + CO ₂ (1)
Then, using the ammonia (NH ₃ ) generated in the formula (1) as a reducing agent, NOx is decomposed into water and nitrogen by the SCR as shown in the following formulas (2) and (3).
4NH ₃ + 4NO + O ₂ → 4N ₂ + 6H ₂ O (2)
4NH ₃ + 2NO ₂ + O ₂ → 3N ₂ + 6H ₂ O (3)

At this time, if the chemical reaction shown in the formula (1) does not occur sufficiently, the amount of ammonia (NH ₃ ) generated is reduced. As a result, ammonia (NH) for causing the chemical reaction in the formula (2) (3) ₃ ) Since the amount is reduced, the NOx purification rate may be reduced, but the filter is placed inside the chassis frame and the catalyst tank and vehicle parts are placed outside the chassis frame. And an injection device for injecting urea water to the inside of the vehicle than the chassis frame. The exhaust inlet of the catalyst tank is connected to the exhaust of the selected catalyst tank. By providing the vehicle outside the outlet, the urea water crosses the chassis frame from the position inside the chassis frame, and outside the vehicle from the exhaust outlet of the catalyst tank. Since the urea water is introduced into the catalyst tank through the pipe extending to the inlet located at, the urea water is easily mixed with the exhaust water in the pipe, and the chemical reaction of formula (1) occurs sufficiently. The NOx purification rate is improved.

  In addition, the vehicle component is a battery mounted on a vehicle, and two locations on both ends of the battery in the vehicle front-rear direction are fixed to the frame via brackets having a U-shaped cross-section, respectively. Each of the U-shaped brackets is attached with a second bracket that extends in the vehicle outer direction and is located on the lower side of the battery, and is provided with a heat insulating plate between the second brackets and on the lower side of the battery. Features.

The battery mounting height position is changed by attaching the battery, which is a vehicle component with the catalyst tank below, to the chassis frame via the U-shaped bracket rather than directly to the chassis frame. It becomes possible. Accordingly, it is possible to deal with batteries having different dimensions. The height of the lower surface of the catalyst tank from the ground can be adjusted by adjusting the mounting height of the U-shaped bracket to the chassis frame, so that the necessary ground height from the ground to the bottom of the catalyst tank can be secured. It becomes possible.
Further, by attaching the battery to the chassis frame via the U-shaped bracket, a space is created at a position surrounded by the battery, the chassis frame, and the two U-shaped brackets. The battery usually has a cable extending from a terminal provided on the upper part, and the cable is connected to other parts located inside the vehicle through a hole provided in the chassis frame. By passing the cable through the space surrounded by the battery, chassis frame, and two U-shaped brackets, and through holes provided in the chassis frame, the cable wiring can be changed to the lower side without greatly changing the cable wiring. It is possible to dispose a catalyst tank.

  Furthermore, by providing a second bracket attached to the U-shaped bracket and a heat insulating plate, the increase in the catalyst tank temperature due to the chemical reaction in the catalyst tank is not easily transmitted to the battery, and the battery temperature rises. Can be reduced.

Further, the two U-shaped brackets have a U-shaped open side as a vehicle front side and a rear side, and at least one of the two U-shaped brackets, The length in the vehicle longitudinal direction of the surface facing the chassis frame is shorter than the length in the vehicle longitudinal direction of the surface facing the battery.
As a result, other members such as rivets for leaf spring gussets can be disposed at positions where the length of the surface of the U-shaped bracket facing the chassis frame is shortened in the vehicle longitudinal direction. Space saving is possible.

Further, a spacer is interposed between the U-shaped bracket and the chassis frame.
A body is attached to the upper portion of the chassis frame via a subframe, a spacer, and a vertical joist. By interposing a spacer between the U-shaped bracket and the chassis frame, it is possible to absorb even if the attachment position of any of the sub-frame, the spacer and the vertical joist on the upper part of the chassis frame is shifted in the vehicle outer direction.

  As described above, according to the present invention, a filter (DPF) that reduces particulate matter (PM) contained in exhaust gas that can be mounted on a vehicle even in a short vehicle such as a dump truck, a mixer, and a garbage truck. And an exhaust purification device provided with a catalyst tank containing a selective reduction type NOx catalyst (SCR) that selectively reduces and purifies NOx in the exhaust in the presence of urea water.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

FIG. 1 is a partial plan view of a vehicle on which the exhaust emission control device 1 according to the first embodiment is mounted, and shows a right front portion of the vehicle.
As shown in FIG. 1, a chassis frame 70 extends from the vehicle in the front-rear direction of the vehicle. Further, a transmission 63 and a differential device 64 connected to the transmission 63 via a drive shaft 65 are provided inside the chassis frame 70. Further, an axle 66 having one end engaged with the gear of the differential device 64 and extending in the vehicle width direction and having the right rear wheel 61 attached to the other end is provided, and a leaf that suspends the axle 66 is provided. A spring 50 is attached to the chassis frame 70.

  In addition, an air tank 62 for storing compressed air used for brakes and suspensions is fixed to the chassis frame 70 on the vehicle outer side of the chassis frame 70, and various lamps such as headlights and brake lamps, wipers, A battery 30 that supplies electricity to electrical components such as a power window is attached to the chassis frame 70 via a U-shaped bracket 11 described later.

Furthermore, an exhaust emission control device 1 that is a characteristic configuration of the present invention is provided.
The configuration of the exhaust purification device 1 and its fixing will be described with reference to FIGS.
2 is a side view of the exhaust purification device 1 and its peripheral devices, FIG. 3 is a perspective view of the exhaust purification device 1 and its peripheral devices, and FIG. 4 is for fixing a catalyst tank 20 containing a selective reduction type NOx catalyst (SCR). It is a perspective view of the mounting bracket 10 for this. 5 is a schematic view showing the positional relationship between the chassis frame 70 and the battery 30. FIG. 6 is a view for explaining the periphery of the attachment portion of the U-shaped bracket to the chassis frame. A) is a side view of the U-shaped bracket, chassis frame and leaf spring around the attachment portion of the U-shaped bracket to the chassis frame, and FIG. 6B is a cross-sectional view taken along the line AA in FIG. is there.

The exhaust emission control device 1 includes a diesel particulate filter (DPF) 40 that collects particulate matter (PM) in engine exhaust (not shown), and a selective reduction type NOx catalyst (SCR) that selectively reduces NOx in the exhaust. ), A center pipe 22 that connects the DPF 40 and the catalyst tank 20, a urea injector 23 that adds urea water called urea into the center pipe 22, and exhaust from the catalyst tank 20 to the outside. It is mainly comprised from the exhaust pipe 21 which does.
The DPF 40 is disposed inside the vehicle of the chassis frame 70, and the catalyst tank 20 is disposed below the battery 30. Further, the positional relationship between the center pipe 22 and the exhaust pipe 21 is such that the connection position between the center pipe 22 and the catalyst tank 20 is outside the vehicle with respect to the connection position between the exhaust pipe 21 and the catalyst tank 20.

The catalyst tank 20 is attached to the chassis frame 70 together with the battery 30 via the mounting bracket 10.
As shown in FIG. 4, the mounting bracket 10 includes two U-shaped brackets 11, two band brackets 14, a heat insulating plate 13, and an SCR bracket 15.
The two U-shaped brackets 11 have a U-shaped cross section, and are arranged so that the open side of the U-shape faces the opposite side. Further, mounting holes 11a, 11b, and 11c (not shown) are provided on three surfaces forming the U-shape, respectively, and by inserting a bolt into the mounting hole 11a, the U-shaped bracket 11 is It is attached to the side wall surface of the chassis frame 70. The mounting hole 11b is used for mounting the battery 30, and the mounting hole 11c is used for mounting the band bracket 14.

The two band brackets 14 have an L-shaped cross section, and are provided with mounting holes 14a, 14b, and 14c. The band bracket 14 has a longitudinal direction in a direction perpendicular to the surface to which the mounting hole 11a of the U-shaped bracket 11 is attached and the surface to which the attachment hole 11b is attached, and on the surface side to which the attachment hole 11b is attached. A bolt is inserted into the mounting hole 11 c of the U-shaped bracket 11 and the mounting hole 14 c of the band bracket so as to protrude, and the U-shaped bracket 11 is mounted.
The heat insulating plate 13 and the SCR bracket 15 are attached between the two band brackets 14 via bolts inserted into the attachment holes 14b.

The mounting bracket 10 composed of the U-shaped bracket 11, the heat insulating plate 13, the band bracket 14 and the SCR bracket 15 is attached to the U-shaped bracket 11 as shown in FIGS. 1 to 3. It is attached to the side wall surface of the chassis frame 70 by inserting a bolt into the provided attachment hole 11a.
More preferably, a spacer 18 is interposed between the U-shaped bracket 11 and the chassis frame 70. As shown in FIG. 2, a body 74 is attached to the upper portion of the chassis frame 70 via a subframe 71, a frame spacer 72, and a vertical joist 73, but between the U-shaped bracket 11 and the chassis frame 70. By interposing the spacer 18, even if the attachment position of any of the sub frame 71, the frame spacer 72, and the vertical joist 73 on the chassis frame 70 is shifted in the vehicle outer side, the shift is absorbed, and the sub frame 71, This is because the frame spacer 72 and the vertical joist 73 can be prevented from interfering with the U-shaped bracket 11.
The height of the U-shaped bracket 11 attached to the chassis frame 70 is determined so that the ground height of the lower surface of the catalyst tank 20 when a tank 20 described later is attached to the mounting bracket 10 is a desired height. To do.

Further, the battery 30 and the catalyst tank 20 are attached to the mounting bracket 10 so that the battery 30 is positioned above the catalyst tank 20.
The battery 30 is attached to the mounting bracket 10 as follows.
A pair of battery mounting members 31 fixed to the battery are attached to the battery 30 so as to cover the bottom surface and two side surfaces of the battery, and mounting holes are provided on one side of the battery mounting member. The battery 30 can be fixed to the U-shaped bracket 11 via the battery mounting member 31 by inserting a bolt between the mounting hole and the mounting hole 11 a of the U-shaped bracket 11. The U-shaped bracket is provided with a plurality of mounting holes 11b in the vertical direction, so that the battery 30 with different dimensions can be accommodated.

On the other hand, the catalyst tank 20 is attached to the attachment bracket 10 as follows.
A band 17 is attached to each of the plurality of attachment holes 14 a provided in the band bracket 14, and the catalyst tank 20 is supported by the band 17. A tank spacer 16 having an upper portion fixed to the SCR bracket 15 by bolts 15 a and a lower portion extending along the upper surface of the tank 20 is applied to the upper surface of the catalyst tank 20 below the SCR bracket 15. It is provided as such.
The catalyst tank 20 is fixed by supporting the lower side of the catalyst tank 20 with the band 17 and supporting the upper side of the catalyst tank 20 with the tank spacer 16.
The temperature of the catalyst tank 20 rises by performing a chemical reaction in the catalyst tank 20, but the raised catalyst tank 20 temperature is increased by the battery 30 by making the top surface of the catalyst tank 20 arcuate in cross section and further providing a heat insulating plate 13. The temperature rise of the battery can be reduced.

Further, the height position of the catalyst tank 20 is determined by the height position of the U-shaped bracket 11 attached to the chassis frame 70 as described above.
Further, the attachment position of the center pipe 22 that supplies exhaust gas into the catalyst tank 20 to the catalyst tank 20 is outside the vehicle, that is, the chassis frame 70, than the attachment position of the exhaust pipe 21 that discharges exhaust gas from the catalyst tank 20 to the tank 20. Keep it on the far side.

  In this manner, the catalyst tank 20 can be saved on the lower side of the battery 30 by using the mounting bracket 10 to save space.

  Further, a space 34 is formed at a position surrounded by the battery 30, the chassis frame 70, and the two U-shaped brackets 11. The battery 30 has a cable 33 extending from a terminal 32 provided on the upper portion, as shown in the schematic diagram showing the positional relationship between the chassis frame 70 and the battery 30 in FIG. Therefore, it is connected to other parts located inside the vehicle through the hole provided in the chassis frame 70 without causing extreme bending. By passing the cable 33 through the space 34 surrounded by the battery 30, the chassis frame 70, and the two U-shaped brackets 11 and the holes provided in the chassis frame 70, the cable wiring on the vehicle inner side than the chassis frame 70 is performed. The size and height position of the battery 30 can be changed without changing the position, that is, the mounting bracket 10 including the U-shaped bracket 11 that supports the battery 30 and the catalyst tank 20 supported by the mounting bracket 10. Since the height position can be changed, the versatility in terms of cable wiring is high.

6A is a side view of the U-shaped bracket, the chassis frame 70 and the leaf spring 50 around the attachment portion of the U-shaped bracket 11 to the chassis frame 70, and FIG. AA sectional view in A) is shown. As shown in FIGS. 6A and 6B, the longitudinal direction of the chassis frame 70 on the surface facing the chassis frame 70 of the U-shaped bracket 11, that is, the length in the vehicle front-rear direction is the surface facing the battery. It was shorter than the length in the vehicle longitudinal direction.
The vehicle is provided with the leaf spring 50 as described above, and the leaf spring 50 is attached to the chassis frame 70 by a rivet 53 with a gusset 52 provided via an eyeball 51.
As described above, the surface of the U-shaped bracket 11 facing the chassis frame 70 is made shorter than the surface facing the battery 30 in the longitudinal direction of the vehicle, so that the gusset 52 And the rivet 53 can be arrange | positioned, and further space saving is attained in arrangement | positioning in a short vehicle.

If for purifying exhaust using such an exhaust gas purification device 1, to generate the NO ₂ is first to oxidize NO in the exhaust at the stage catalyst, not shown, supplies the DPF40 the NO ₂ as oxidizing agent. The front catalyst may be provided separately from the DPF 40, but may be integrated into a front catalyst and a DPF that are housed in the same casing as the DPF 40 and house the front catalyst and the DPF.

In the DPF 40, PM in exhaust gas is collected and removed, and the collected PM is combusted by reaction with NO ₂ supplied from the preceding catalyst.

The exhaust gas collected and removed by the DPF 40 is mixed with urea water called urea injected from the urea injector 23 through the center pipe 22 and supplied to the SCR stored in the catalyst tank 20. The urea water is an aqueous solution of urea, and an aqueous solution of 32.5% urea that can be supplied at a truck station or the like can be used. The urea water is stored in a urea water tank (not shown), and is supplied into the center pipe 22 from the urea injector 23 when the vehicle starts operation and exhausts.
When urea water is injected into the exhaust gas, the urea water is atomized and diffused in the center pipe 22 and is hydrolyzed by the heat of the exhaust gas as shown in the chemical formula (1) below, and ammonia (NH ₃ ) and Carbon dioxide (CO ₂ ) is generated.
(NH ₂ ) ₂ CO + H ₂ O → 2NH ₃ + CO ₂ (1)
At this time, if the center pipe 22 cannot secure a sufficient length, the urea water does not atomize and diffuse well, and the exhaust and urea water reach the catalyst tank 20 before the reaction (1) occurs. However, the DPF 40 is disposed inside the chassis frame 70 and the catalyst tank 20 is disposed outside the chassis frame 70, and the exhaust inlet portion of the center pipe 22 to the catalyst tank 20 is connected to the exhaust outlet portion of the catalyst tank 20. The exhaust pipe and the urea water cross the chassis frame 70 from the position inside the chassis frame 70 to reach the inlet portion located outside the vehicle rather than the exhaust outlet portion of the catalyst tank 20. Since it is introduced into the catalyst tank 20 via the inside 22, a sufficient length of the center pipe 22 can be ensured, and the urea water is fed into the center pipe. Are uniformly mixed with the exhaust water in the 2, (1) chemical reaction formula occurs sufficiently.

In the catalyst tank 20, the SCR decomposes NOx into water and nitrogen as shown in the following formulas (2) and (3) using the ammonia (NH ₃ ) generated in the formula (1) as a reducing agent.
4NH ₃ + 4NO + O ₂ → 4N ₂ + 6H ₂ O (2)
4NH ₃ + 2NO ₂ + O ₂ → 3N ₂ + 6H ₂ O (3)
(2) Ammonia (NH ₃ ) is required for the reaction of formula (3) to occur, but in this embodiment, the length of the center pipe 22 for generating the reaction of formula (1) is sufficiently long. since the secured, ammonia (NH ₃₎ amount sufficient can be secured, it is possible to ensure a high NOx purification rate.

Further, the exhaust gas obtained by decomposing NOx into water and nitrogen by the SCR in the catalyst tank 20 oxidizes ammonia (NH ₃ ) surplus in the SCR by a later stage catalyst (not shown) to generate N _2, and at the DPF 40 When CO is generated with the combustion of PM, it is oxidized to generate CO ₂ . The rear catalyst is stored in the catalyst tank 20 together with the SCR.

  In this way, the exhaust gas can be purified by the front stage catalyst, the DPF 40, the center pipe 22, the SCR in the catalyst tank 20, and the rear stage catalyst. Furthermore, since the catalyst tank 20 is disposed below the battery 30, the catalyst tank 20 constituting the exhaust gas purification device 1 can be installed in a small space. Therefore, even a short vehicle such as a dump truck, a mixer, a garbage truck, etc. Can be mounted on a vehicle.

  Even short vehicles such as dump trucks, mixers, and garbage trucks can be mounted in the vehicle and exhausted in the presence of a filter (DPF) that reduces particulate matter (PM) contained in the exhaust gas and urea water. The present invention can be used as an exhaust emission control device provided with a catalyst tank containing a selective reduction type NOx catalyst (SCR) that selectively reduces and purifies NOx therein.

1 is a partial plan view of a vehicle on which an exhaust emission control device 1 according to a first embodiment is mounted. It is a side view of the exhaust emission control device 1 and its peripheral equipment. 1 is a perspective view of an exhaust purification device 1 and its peripheral devices. It is a perspective view of the mounting bracket 10 for fixing the catalyst tank 20 which accommodated the selective reduction type NOx catalyst (SCR). 4 is a schematic diagram showing a positional relationship between a chassis frame 70 and a battery 30. FIG. It is a figure for demonstrating the attachment part periphery to the chassis frame of a U-shaped bracket.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exhaust purification device 10 Mounting bracket 11 U-shaped bracket 13 Heat insulation plate 14 Band bracket 15 SCR bracket 16 Tank spacer 17 Band 18 Spacer 20 Catalyst tank 21 Exhaust pipe 22 Center pipe 30 Battery 40 Diesel particulate filter (DPF)
70 Chassis frame

Claims (6)

In the exhaust passage of the internal combustion engine mounted on the vehicle, in order from the upstream side of the exhaust flow, a filter that collects particulate matter contained in the exhaust gas and NOx in the exhaust in the presence of urea water are selected In an exhaust purification device provided with a catalyst tank containing a selective reduction type NOx catalyst for reducing and purifying automatically,
The filter and the catalyst tank are each attached to a vehicle body and connected by piping,
An exhaust emission control device, wherein the catalyst tank is disposed below a vehicle part attached to a chassis frame extending in the front-rear direction of the vehicle.   2. The exhaust emission control device according to claim 1, wherein the catalyst tank has an arcuate cross section at the top, and the vehicle parts have a planar shape at the bottom, and are coupled to each other in a line contact state. The filter is disposed inside the chassis frame and the catalyst tank and the vehicle parts are disposed outside the chassis frame.
An injection device for injecting urea water is provided on the vehicle inner side than the chassis frame in the pipe connecting the filter and the tank,
The exhaust emission control device according to claim 1 or 2, wherein the exhaust inlet portion of the catalyst tank is provided outside the vehicle with respect to the exhaust outlet portion of the catalyst tank. The vehicle component is a battery mounted on a vehicle,
Two locations on both ends of the battery in the longitudinal direction of the battery are fixed to the frame via brackets having a U-shaped cross section,
Each of the two U-shaped brackets is attached with a second bracket that extends in the vehicle outer direction and is located on the lower side of the battery, and has a heat insulating plate between the second brackets and on the lower side of the battery. The exhaust emission control device according to claim 3 provided. The two U-shaped brackets, the open side of the U-shaped cross section as the vehicle front side and the rear side,
For at least one U-shaped bracket of the two U-shaped brackets, the length of the surface facing the chassis frame in the vehicle longitudinal direction is greater than the length of the surface facing the battery in the vehicle longitudinal direction. The exhaust emission control device according to claim 4, wherein the exhaust purification device is shortened.   The exhaust emission control device according to claim 4 or 5, wherein a spacer is interposed between the U-shaped bracket and the chassis frame.

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