WO2024095500A1

WO2024095500A1 - Tank

Info

Publication number: WO2024095500A1
Application number: PCT/JP2022/041270
Authority: WO
Inventors: 久人月元
Original assignee: 三菱自動車工業株式会社
Priority date: 2022-11-04
Filing date: 2022-11-04
Publication date: 2024-05-10

Abstract

This tank stores an additive for vehicle exhaust emission control. The tank comprises a pump that is installed on a bottom wall of the tank and that draws in the additive and discharges the additive to outside the tank, and a storage wall that is erected on the bottom wall so as to be spaced apart from a side outer wall of the tank and surrounds the entire periphery of the pump.

Description

tank

The present invention relates to a tank that stores additives for purifying exhaust gas from vehicles.

　Conventionally, one method for purifying nitrogen oxides (NOx) in exhaust gas emitted from diesel engines involves hydrolyzing an additive such as urea water (additive aqueous solution) on a catalyst to generate ammonia (NH3), which is then used to selectively reduce and purify the nitrogen oxides contained in the exhaust gas. An exhaust purification device with this function is called urea selective catalytic reduction. Vehicles equipped with urea selective catalytic reduction are equipped with a tank for storing the additive.

The urea tank described in Patent Document 1 includes a urea water pump having an inlet through which urea water flows and an outlet through which the urea water sucked in from the inlet is discharged below the urea water tank, and a liquid reservoir wall that is curved around the urea water pump and stands upright from the bottom wall.

Japanese Patent Publication No. 2020-192876

In the technology disclosed in Patent Document 1, when the liquid level of the additive in the tank becomes low, the reservoir wall disrupts the fluidity of the additive that crosses the reservoir wall, and further generates fluidity along the curved surface of the reservoir wall, creating a fluid state in which the additive is less likely to freeze, even in cold regions. By adopting this technology, it is possible to see the effect of making the additive less likely to freeze. However, when it comes to cold region countermeasures for additives, the current situation is that technology that reduces the effects of external temperatures more than ever before is required.

The present invention was made in consideration of these problems, and its purpose is to provide a tank that is less susceptible to the effects of external temperatures.

To achieve the above objective, the present invention has, for example, the following configuration.

(1) A tank for storing an additive for purifying exhaust gas from a vehicle, comprising:
a pump installed on a bottom wall of the tank for sucking the additive and discharging it to the outside of the tank;
a storage wall that is erected on the bottom wall so as to be spaced apart from a side outer wall of the tank and that surrounds the entire periphery of the pump;
A tank comprising:
(2) The storage wall is
A first wall portion surrounding the pump;
a second wall portion surrounding at least a portion of the first wall portion;
having
An inner storage portion surrounded by the first wall portion and an outer storage portion surrounded by the first wall portion and the second wall portion are formed on the inside of the storage wall.
A tank as described in (1).
(3) The storage wall is
A first opening connecting the inner reservoir and the outer reservoir;
A second opening connecting the outer reservoir and an area outside the outer reservoir;
having
In a plan view, the first opening and the second opening are arranged so as to be separated by 180° or more in a circumferential direction relative to the center of the inner storage portion.
A tank as described in (2).
(4) The second wall portion has a first opening side portion located on the first opening side and a second opening side portion located on the second opening side,
The outer side wall has a side wall portion adjacent to the second opening side portion,
the second opening side portion is gradually spaced from the side wall portion as it approaches the second opening;
(3) A tank as described in (3).
(5) The outer storage portion has a widened portion in which a width between the first wall portion and the second wall portion in a plan view is wider than an opening width of the second opening portion in a plan view.
A tank as described in (3) or (4).
(6) The widening portion is provided in the vicinity of the first opening.
A tank as described in (5).
(7) The tank further includes a sub-wall portion provided on the bottom wall of the tank outside the storage wall,
The sub-wall portion is disposed opposite the second opening.
A tank according to any one of (3) to (6).
(8) The sub-wall portion is connected to an outer surface of the storage wall.
(7) A tank as described in (7).
(9) The second wall portion has a first opening side portion located on the first opening side and a second opening side portion located on the second opening side,
The outer side wall has a side wall portion adjacent to the second opening side portion,
the sub-chamber wall extends from the outer surface of the storage wall toward the side wall of the tank,
The sub-chamber wall has a bent portion in the middle of its extension such that a tip portion thereof faces the second opening side.
(8) A tank as described in (8).
(10) The second wall portion has a first opening side portion located on the first opening side and a second opening side portion located on the second opening side,
The outer side wall has a side wall portion adjacent to the second opening side portion,
the sub-wall portion is spaced from the side wall portion of the tank;
A third opening is formed between the sub-wall portion and the side wall portion,
The second opening and the third opening are offset in the vehicle front-rear direction.
A tank according to any one of (7) to (9).
(11) The inner reservoir is provided with a heater disposed adjacent to the pump and configured to heat the additive.
A tank according to any one of (2) to (10).
(12) The tank is elongated in the vehicle front-rear direction,
The pump and the storage wall surrounding the pump are disposed on one side of the tank in a vehicle front-rear direction,
The storage wall has a height on one side greater than a height on the other side in the vehicle front-rear direction.
A tank according to any one of (1) to (11).
(13) The tank has an elongated shape extending in the front-rear direction of the vehicle,
The pump and the storage wall surrounding the pump are disposed on one side of the tank in a vehicle front-rear direction,
The storage wall has a height on one side in the vehicle front-rear direction greater than a height on the other side, with the portion where the sub-wall portion is connected as a boundary.
(8) A tank as described in (8).

The present invention provides a tank that is less susceptible to the effects of external temperatures.

FIG. 2 is a bottom view of a vehicle to which the tank of the present invention can be applied. FIG. 2 is an external perspective view of the tank shown in FIG. 1 . FIG. 4 is a bottom view showing the mounting structure of the tank. FIG. 2 is a plan view showing a tank and its accessories mounted on the vehicle shown in FIG. 1 . FIG. FIG. 6 is an enlarged view of the tank of FIG. FIG. 2 is an enlarged perspective view of a main portion inside the tank. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 6.

Below, a tank according to one embodiment of the present invention will be described with reference to the drawings. Note that in the description with reference to each figure, the vehicle is described as having a front-to-rear direction, a left-to-right direction (vehicle width direction), and a top-to-bottom direction as seen by the driver (passenger) of the vehicle. Also, in each figure, the directions of the vehicle's front-to-rear direction, left-to-right direction, and top-to-bottom direction are indicated by arrows.

FIG. 1 is a bottom view of a vehicle to which the tank of the present invention can be applied.
A vehicle 1 shown in Fig. 1 is equipped with a diesel engine and an additive selective catalytic reduction (SCR) system using, for example, urea, in order to purify nitrogen oxides in the exhaust gas discharged from the engine. The additive selective catalytic reduction system is a system in which an additive is injected into an exhaust pipe 7 through which exhaust gas passes, and nitrogen oxides are reduced to nitrogen on a catalyst using ammonia produced by hydrolysis of the additive as a reducing agent and discharged. The additive selective catalytic reduction system is applied to vehicles equipped with diesel engines and lean burn engines where nitrogen oxide emissions are a problem.

As shown in Figure 1, the body structure of the vehicle 1 is a structure in which the body is mounted on a frame that includes

side members

2, 2, which are two front and rear frames that extend in the fore-and-aft direction of the vehicle 1, and cross members 4, which are left and right frames that connect the

side members

2, 2 in the width direction (left and right direction) of the vehicle 1.

The

side members

2, 2 are located under the floor at least near the rear of the vehicle 1 and are spaced apart in the vehicle width direction. In FIG. 1, only the portions of the

side members

2, 2 at least near the rear of the vehicle 1 are shown.

Cross members 4 are provided in multiple locations along the front-to-rear direction, and a floor panel that forms part of the body is fixed to the upper surfaces of the

side members

2, 2. Note that in Figure 1, only one cross member 4 located rearward of the axle (drive shaft) 5 located between the left and right

rear wheels

3, 3 is shown, and the other cross members 4 are not shown.

In addition, in this embodiment, a differential is disposed between the left and

right axles

5, 5, and a propeller shaft, transmission, etc. are connected to the differential in this order toward the front. Also, the

rear wheels

3, 3 shown in the figure are drive wheels, but the front wheels may be drive wheels instead of the

rear wheels

3, 3.

An emergency tire wheel 6 (hereafter referred to as the spare tire 6) is stored under the floor panel near the rear of the vehicle 1. The spare tire 6 is detachably suspended and fixed to the cross member 4 rearward of the axle 5 via a specified fastener (e.g., bolts and nuts). Note that in some cases, the spare tire 6 can be raised and lowered by winding up and down a chain.

An exhaust pipe 7 extending from the engine is disposed under the floor panel of the vehicle 1. In this exhaust pipe 7, an exhaust purification device 50 consisting of urea selective catalytic reduction, a muffler (silencer) 8, and the like are provided along the flow direction of the exhaust gas. Here, the exhaust purification device 50 is part of the additive selective catalytic reduction system described above. A nozzle (not shown) for injecting the additive is provided inside the exhaust pipe 7 (including inside the exhaust purification device 50). The nozzle for injecting the additive is generally disposed upstream of the exhaust purification device 50, but the injection position is selected appropriately depending on the specifications.

Furthermore, a tank 10 that stores a certain amount of additive for purifying the exhaust gas of the vehicle 1 is mounted under the floor panel and close to the spare tire 6 in order to supply the additive into the exhaust pipe 7. In the illustrated example, the spare tire 6 is located in the center of the vehicle 1 in the left-right direction, and the tank 10 is located on the left side, which is outside the spare tire 6 in the left-right direction. The location of the tank 10 is not particularly limited, and for example, the tank 10 may be located to the right of the spare tire 6.

Figure 2 is an external perspective view of the tank shown in Figure 1. Figure 3 is a bottom view showing the mounting structure of the tank. Figure 4 is a plan view showing the tank and its accessories mounted on the vehicle shown in Figure 1. Figure 5 is a horizontal cross-sectional view of the tank. Figure 6 is an enlarged view of the tank in Figure 5. Figure 7 is an enlarged perspective view of the main parts inside the tank.

As shown in FIG. 4, an additive injection pipe 31, a leveling pipe 32, and a vent pipe 33 are connected to the top of the tank 10 (the side facing the paper of FIG. 4).

The additive injection pipe 31 is a pipe member that refills additives such as urea water into the tank 10. The additive injection pipe 31 is, for example, a passage that is pulled out from an injection port 31c provided in the front wall 12c of the tank 10 and refills additives from the outside through an inlet 31b of an additive filler 31a provided in an appropriate position on the vehicle 1.

The leveling pipe 32 is a passage that allows air inside the tank 10 to escape to the additive filler 31a side when refilling the additive.

The vent pipe 33 is a passage that releases the internal gas to the atmosphere when the pressure inside the tank 10 increases. An atmosphere release valve that opens and closes the passage is provided midway along the vent pipe 33. The atmosphere release valve opens when the internal pressure of the tank 10 reaches or exceeds a set pressure.

A signal cable 34 and a power cable 35 are connected to the tank 10 to drive the components of the electrical system.

An additive supply pipe 36 that sends additives to the exhaust pipe 7 is connected to the bottom of the tank 10 (the back side of the paper in FIG. 4). By the action of the pump 18 described below, the additives are sent from a delivery port 36c (see FIG. 5) provided in the bottom wall 11 of the tank 10 through the additive supply pipe 36 to the exhaust pipe 7.

The tank 10 may be a molded product made of, for example, a metal with excellent corrosion resistance such as stainless steel, a resin such as polyethylene or polypropylene, or a fiberglass reinforced plastic (FRP). The tank 10 may also be made by integrally molding multiple molded members using known techniques such as welding, gluing, or fusion.

A cover (not shown) is attached as a protective member to the bottom of the tank 10 so as to cover all or part of the tank 10. This cover protects the tank 10 from impacts and preferably has a certain level of insulation to prevent excessive temperature changes in the additives.

As shown in FIG. 2, the tank 10 has a hollow structure formed by joining the open sides of a bottomed, concave lower member 10b that opens upward and has a bottom wall 11, and a bottomed, concave upper member 10a that opens downward and has a top wall 13.

As shown in Figures 5 to 7, a recess 11b that is deeper than other portions is recessed into the bottom wall 11 of the lower member 10b of the tank 10. In the illustrated example, the recess 11b has a circular cross section, but the shape of the recess 11b is not particularly limited. Also, in the illustrated example, the recess 11b is located on one side in the front-to-rear direction (the rear side in the illustrated example) of the tank 10, which is elongated in the front-to-rear direction, but the location of the recess 11b is not particularly limited.

Inside the recess 11b, there is provided a pump 18 that sucks in the additive using the driving force of a motor or the like and discharges it outside the tank 10, and a heater 19 that is arranged adjacent to the pump 18 and heats the additive to an appropriate predetermined temperature. The additive is sent out by the pump 18 from the delivery port 36c provided in the recess 11b through the additive supply pipe 36 (see FIG. 4) to the exhaust pipe 7 side. In addition, a storage wall 20 is provided on the bottom wall 11 so as to surround the recess 11b, the details of which will be described later.

The tank 10 has side outer walls 12 that define the four sides of the tank 10: front, rear, left and right. The side outer walls 12 include an outer wall 12a located on the left and right outer side member 2 side (left side), an arc-shaped inner wall 12b located on the left and right inner side spare tire 6 side (right side), a front wall 12c located on the front side, and a rear wall 12d located on the rear side. The outer wall 12a, inner wall 12b, front wall 12c, and rear wall 12d are connected to each other and close the tank 10 on all four sides: front, rear, left and right.

As shown in FIG. 5, the tank 10 includes an extension 10d in which the pump 18 and heater 19 are disposed, and a connection 10c extending forward from the extension 10d to a front wall 12c in which an inlet 31c for an additive from outside is provided. The extension 10d is wider in the left-right direction than the connection 10c, forming a large space capable of accommodating the pump 18 and heater 19. The extension 10d is formed toward the rear of the tank 10 so that the additive can easily flow in when the vehicle 1 is inclined upward. In order to secure this large space, the extension 10d utilizes a large space on the rear side of the vehicle 1 from the center of the spare tire 6, which is circular in plan view (see FIGS. 1 and 4). The center of the spare tire 6 is the center position of the wheel of the spare tire 6.

The rear expansion section 10d of the tank 10 is set to a maximum width L2 in the left-right direction. Furthermore, the length L1 in the vehicle's fore-and-aft direction is greater than the maximum width L2 in the left-and-aft direction (L1>L2). Therefore, the tank 10 is elongated and extends in the vehicle's fore-and-aft direction.

As shown in Figures 2 to 4, the side outer wall 12 of the tank 10, which is elongated in the front-rear direction, is provided with multiple brackets 29 that protrude in the left-right direction of the vehicle. In the illustrated example, three brackets 29 are provided, with one bracket 29 protruding outward in the left-right direction from the rear of the outer wall 12a of the side outer wall 12, and two

brackets

29, 29 protruding inward in the left-right direction from the front and rear of the inner wall 12b of the side outer wall 12, respectively. The tank 10 is detachably attached to the underside of the floor panel via the multiple brackets 29. The brackets 29 are provided with mounting holes 29a through which fastening members such as bolts can pass to detachably attach the tank 10.

Of the multiple brackets 29, the left bracket 29 provided on the outer wall 12a is directly fixed to the side member 2 by a bolt or the like inserted into the mounting hole 29a.

Of the multiple brackets 29, the two

right brackets

29, 29 provided on the inner wall 12b are attached to the cross member 4 via a first auxiliary frame 41 and a second auxiliary frame 42. The first auxiliary frame 41 and the second auxiliary frame 42 extend from the cross member 4 in the fore-and-aft direction of the vehicle above the spare tire 6 (see FIG. 1). The two

brackets

29, 29 are fixed to the first auxiliary frame 41 and the second auxiliary frame by bolts or the like inserted into mounting

holes

29a, 29a.

As shown in FIG. 4, the arc-shaped inner wall 12b of the tank 10 is adjacent to the spare tire 6 over almost its entire surface with only a small gap between them, so it is less susceptible to temperature changes from the outside than the other parts of the side outer wall 12 (the outer wall 12a, the front wall 12c, and the rear wall 12d).

The tank 10 is also positioned to the left of the spare tire 6, and the exhaust pipe 7 is positioned to the right of the spare tire 6. This suppresses the thermal effects of the hot components of the exhaust pipe 7 and the exhaust gas released into the atmosphere, and prevents the temperature of the tank 10 and the additives inside the tank 10 from rising excessively. It is also possible to reverse the left and right positions of the openings 9 of the tank 10 and exhaust pipe 7, so that the tank 10 is positioned to the right of the spare tire 6 and the exhaust pipe 7 is positioned to the left of the spare tire 6.

As shown in Figures 5 to 7, a storage wall 20 is provided on the bottom wall 11 within the expansion section 10d of the tank 10 so as to be spaced apart from the side outer wall 12. The storage wall 20 rises vertically (upward) from the bottom wall 11 outside the recess 11b. The storage wall 20 also surrounds the entire circumference of the pump 18. "Surviving the entire circumference of the pump 18" means that the storage wall 20 is provided over 360° or more in the circumferential direction centered on the pump 18. Therefore, the storage wall 20 has a so-called spiral shape in a plan view.

In this way, since the storage wall 20 is provided so as to surround the entire circumference of the pump 18, the movement of the additive due to the change in acceleration accompanying the acceleration/deceleration or turning of the vehicle 1 is restricted, and the additive can be retained inside the storage wall 20. As a result, even if the amount of additive remaining in the tank 10 is small, for example, the additive can be retained near the pump 18, and the additive can be reliably flowed into the pump 18. In addition, since the storage wall 20 surrounding the pump 18 is provided so as to be spaced away from the outer side wall 12 of the tank 10, the additive near the pump 18 inside the storage wall 20 is prevented from coming into direct contact with the outer side wall 12 of the tank 10. This reduces the effect of the temperature outside the tank 10 on the additive near the pump 18.

In the illustrated example, a heater 19 is provided in the recess 11b and is disposed adjacent to the pump 18. Therefore, the storage wall 20 surrounds not only the pump 18 but also the entire periphery of the heater 19.

The storage wall 20 has a first wall portion 21 that is disposed outside the pump 18 and the heater 19 and surrounds the pump 18 and the heater 19, and a second wall portion 22 that is disposed outside the first wall portion 21 and surrounds at least a portion of the first wall portion 21. On the inside of the storage wall 20, an inner storage portion 23 surrounded by the first wall portion 21, and an outer storage portion 24 surrounded by the first wall portion 21 and the second wall portion 22 are formed.

In this way, the inner reservoir 23 surrounded by the first wall 21 and the outer reservoir 24 surrounded by the first wall 21 and the second wall 22 are formed inside the reservoir wall 20, so that a plurality of reservoir areas for the additive are provided. This makes it possible to suppress the movement of the additive away from the pump 18. As a result, it is possible to enhance the effect of retaining the additive near the pump 18.
Furthermore, since the first wall portion 21 and the second wall portion 22 are provided at a double-walled portion at a predetermined distance from each other, the heat insulating effect of the storage wall 20 can be enhanced. This makes it possible to more effectively reduce the influence of the external temperature of the tank 10.

The inner reservoir 23 is provided with not only the pump 18 but also a heater 19 that is disposed adjacent to the pump 18 and heats the additive. This makes it possible to more reliably prevent the additive flowing into the pump 18 from freezing.

The first wall portion 21 and the second wall portion 22 are formed into a continuous spiral shape on the vehicle front side and left side of the storage wall 20. The storage wall 20 is provided near the continuous portion between the first wall portion 21 and the second wall portion 22, and has a first opening 21h that connects the inner storage portion 23 and the outer storage portion 24, and a second opening 22h that connects the outer storage portion 24 and the area outside the outer storage portion 24 (the auxiliary chamber 30 described below).

As shown in FIG. 6, the inner starting end 21a of the first wall portion 21, which is the inner starting end of the spiral shape of the storage wall 20, is located forward and to the left of the pump 18 and heater 19. The first wall portion 21 extends in an arc from the starting end 21a so as to surround the pump 18 and heater 19. The end 21b of the first wall portion 21 is positioned in front of the starting end 21a with a gap therebetween, and a first opening 21h is provided between the end 21b and the starting end 21a.

The second wall portion 22 has a first opening side portion 221 located on the side of the first opening 21h, and a second opening side portion 222 located on the side of the second opening 22h.

The first opening side portion 221 has an L-shaped cross section, with a left-right extending portion 221a that connects to the end 21b of the first wall portion 21 and extends to the left, and a front-rear extending portion 221b that extends rearward from the left end of the left-right extending portion 221a. The front-rear extending portion 221b is disposed approximately parallel to the outer wall 12a of the side outer wall 12 at a predetermined distance.

The second opening side portion 222 is connected to the rear end of the first opening side portion 221 and extends in the left-right direction behind the first wall portion 21. The rear wall 12d of the side outer wall 12 is a side wall portion adjacent to the second opening side portion 222. From the left end of the second opening side portion 222 to near the center in the left-right direction, it is arranged approximately parallel to the rear wall 12d of the side outer wall 12 at a predetermined distance, but curves forward so as it moves from near the center in the left-right direction toward the right side, i.e., as it approaches the second opening 22h.

By configuring the second wall portion 22 in this way, the space inside the tank 10 can be used efficiently. Furthermore, since the second opening 22h can be positioned away from the rear side wall 12d, the effect of the temperature outside the tank on the additive flowing in from the second opening 22h can be reduced.

The end 222a of the second opening side portion 222 of the second wall portion 22, which is the outer end of the spiral shape of the storage wall 20, is located rearward and to the right of the pump 18 and heater 19. A second opening 22h is formed between this end 222a and the first wall portion 21. The second opening 22h connects the outer storage portion 24 to the auxiliary chamber 30, which is the area outside the outer storage portion 24.

As shown in FIG. 6, the first opening 21h and the second opening 22h are positioned so as to be separated by 180° or more in the circumferential direction with respect to the center C of the inner storage section 23 in a plan view.

In this way, the first opening 21h and the second opening 22h are positioned so that they are separated by 180° or more in the circumferential direction relative to the center C of the inner storage portion 23 in a plan view, so that the outer storage portion 24 can be provided with a curved shape that is long in the circumferential direction and is 180° or more. This improves the ability of the outer storage portion 24 to retain additives. In addition, because the portion where the first wall portion 21 and the second wall portion 22 are doubled is long, the effect of the external temperature on the tank 10 can be reduced.

Here, heat is transferred by the heater 19 in the following order: additive in the inner storage section 23, additive in the first opening 21h, additive in the outer storage section 24, and additive in the second opening 22h. Therefore, the larger the separation angle between the first opening 21h and the second opening 22h is set beyond 180°, the greater the additive retention capacity of the outer storage section 24 and the effect of reducing the external temperature influence by doubling the storage wall 20 will be, but it will be more difficult for the heater 19 to heat the additive in the outer storage section 24 and the second opening 22h, and there is a risk that the additive will freeze in these locations in a cold climate. Therefore, from the viewpoint of achieving both the additive retention capacity of the outer reservoir 24 and the reduction of the influence of external temperature due to the doubling of the reservoir wall 20, and the prevention of freezing of the additive in the outer reservoir 24 and the second opening 22h, it is preferable that the first opening 21h and the second opening 22h are 180° or more and 360° or less in the circumferential direction relative to the center C of the inner reservoir 23 in a plan view. In the example of FIG. 6, the first opening 21h and the second opening 22h are arranged so as to be exactly 180° apart in the circumferential direction relative to the center C of the inner reservoir 23 in a plan view.

The outer storage section 24 also has a front widening section 25 and a rear widening section 26 in which the widths L4, L5 between the first wall section 21 and the second wall section 22 in a plan view are wider than the opening width L3 of the second opening 22h in a plan view. In the illustrated example, the widths L4, L5 of the front widening section 25 and the rear widening section 26 are wider than the opening width L3 of the second opening 22h, and are also wider than the opening width of the first opening 21h.

The front widening portion 25 is located at the front and left corner of the storage wall 20. That is, the front widening portion 25 is located closer to the first opening 21h than the second opening 22h. More specifically, the front widening portion 25 is formed between the first wall portion 21 and the corner where the left-right extending portion 221a and the front-rear extending portion 221b of the first opening side portion 221 of the second wall portion 22 are connected.

The rear widening portion 26 is located at the rear and left corner of the storage wall 20. That is, the rear widening portion 26 is located approximately halfway between the first opening 21h and the second opening 22h. More specifically, the rear widening portion 26 is formed between the first wall 21 and the corner where the front-rear extending portion 221b of the first opening side portion 221 of the second wall 22 and the second opening side portion 222 are connected.

In this way, by having the outer storage section 24 with the wide front widening section 25 and rear widening section 26, it is possible to store more additive within the outer storage section 24.

Furthermore, the front widening portion 25 is provided near the first opening 21h. In this way, by providing the front widening portion 25 at a location close to the first opening 21h, the amount of additive stored in the area of the outer storage portion 24 close to the inner storage portion 23 can be increased. Here, when the frozen additive is thawed, the additive is thawed in order from the portion closest to the first opening 21h. Therefore, by providing the front widening portion 25 at a location close to the first opening 21h, the thawing of the additive can be progressed more efficiently.

The tank 10 further has a sub-wall portion 28 erected on the bottom wall 11 of the tank 10 outside the storage wall 20. The sub-wall portion 28 rises vertically (upward) from the bottom wall 11. The sub-wall portion 28 is disposed so as to face the second opening 22h. In other words, the sub-wall portion 28 is located on an extension line of the second opening 22h in the opening direction.

By arranging the sub-wall portion 28 opposite the second opening 22h in this manner, a storage area that can be called a sub-chamber 30 in which additives can be secondarily stored can be formed in the opposing area between the sub-wall portion 28 and the second opening 22h on the outside of the storage wall 20.

The sub-wall portion 28 does not necessarily have to be connected to the outer surface of the storage wall 20, but in this embodiment, the base 28a of the sub-wall portion 28 is connected to the outer surface of the storage wall 20. In the illustrated example, the base 28a of the sub-wall portion 28 is connected to the right side and near the center in the front-to-rear direction of the outer surface of the arc-shaped first wall portion 21. Therefore, the front of the sub-chamber 30 formed by the sub-wall portion 28 and the second opening 22h is closed, so that the additive can be more reliably stored in the sub-chamber 30.

The sub-wall portion 28 extends from the outer surface of the storage wall 20 toward the rear wall 12d (side wall portion) of the tank 10. Furthermore, the sub-wall portion 28 has a bent portion 28c in the middle of its extension so that its tip portion 28b faces the second opening 22h side (left side). More specifically, the sub-wall portion 28 has a base portion 28a that connects to the outer surface 20a of the storage wall 20, an inclined portion 28d that inclines to the right as it extends rearward from the base portion 28a, a bent portion 28c that is the tip of the inclined portion 28d, an extension portion 28e that extends rearward from the bent portion 28c, and a tip portion 28b that is the tip of the extension portion 28e. The inclined portion 28d extends at an angle of about 45° in the left-right direction relative to the front-rear direction, and the extension portion 28e extends approximately parallel to the front-rear direction.

In this way, the sub-wall portion 28 has a bent portion 28c that is bent midway through its extension so that its tip portion 28b faces the second opening 22h, so that the additive can be more reliably stored in the sub-chamber 30, which is the area surrounded by the storage wall 20 and the sub-wall portion 28.

The tip 28b of the sub-wall 28 is spaced apart from the rear wall 12d (side wall) of the tank 10. A third opening 28h is formed between the tip 28b of the sub-wall 28 and the rear wall 12d (side wall).

The second opening 22h and the third opening 28h are offset in the fore-and-aft direction of the vehicle 1. In the example of FIG. 6, the length of the extension portion 28e is set so that the tip end 28b of the sub-wall portion 28 is located rearward of the second opening 22h. As a result, the third opening 28h is offset rearward from the second opening 22h.

In this way, by offsetting the second opening 22h and the third opening 28h in the fore-and-aft direction of the vehicle 1, direct, linear flow of additive between the second opening 22h and the third opening 28h is suppressed, the auxiliary chamber 30 can be effectively used as a storage area, and the additive can be stored more reliably.

As described above, the tank 10 is configured in an elongated shape (L1>L2) that extends in the fore-and-aft direction of the vehicle 1. When the tank 10 is long in the fore-and-aft direction of the vehicle like this, additives may move in the fore-and-aft direction and become unevenly distributed when the vehicle 1 accelerates or decelerates or travels on an incline. However, the pump 18 and the storage wall 20 that surrounds it are provided on one side of the tank 10 in the fore-and-aft direction of the vehicle (the rear side in this embodiment), which makes it easier to store unevenly distributed additives.

Figure 8 is a cross-sectional view taken along line VIII-VIII in Figure 6. As shown in Figure 8, the storage wall 20 is formed so that the height H2 on one side (front side) in the vehicle fore-and-aft direction is greater than the height H1 on the other side (rear side) (H2>H1).

More specifically, referring also to FIG. 6, of the storage wall 20, (i) the portion of the first wall portion 21 from the starting end 21a to the point where the base 28a of the sub-wall portion 28 is connected, and (ii) the portion of the second wall portion 22 including the front-rear extending portion 221b of the first opening side portion 221 and the second opening side portion 222 are set to a relatively low constant height H1.

On the other hand, the height H2 of (i) the portion of the storage wall 20 from the point where the base 28a of the sub-wall portion 28 of the first wall portion 21 is connected to the end 21b, and (ii) the left-right extending portion 221a of the first opening side portion 221 of the second wall portion 22 is set higher than the height H1 (H2>H1). In particular, (i) the portion of the first wall portion 21 from the point where the base 28a of the sub-wall portion 28 is connected to the end 21b is inclined upward so that the height H2 gradually increases toward the front side, and the height H2 reaches a maximum value H2max near the front end. Also, (ii) the height H2 of the left-right extending portion 221a of the first opening side portion 221 of the second wall portion 22 is the maximum value H2max.

In this way, the height H2 of the other side (front side) of the storage wall 20 is set to be higher than the height H2 of one side (rear side), with the boundary being the portion of the storage wall 20 where the base 28a of the sub-wall portion 28 is connected.

In this way, the storage wall 20 is formed with a higher height H2 on the other side (front side) opposite to the side (rear side) on which the storage wall 20 and the pump 18 are provided, so that the additive can be retained within the storage wall 20 even when the vehicle 1 is accelerating or decelerating or when driving on an incline.
In addition, since the storage wall 20 has high and low parts, when an additive is injected from the outside into the tank 10 through the additive injection pipe 31 (see FIG. 4), the additive can be smoothly supplied into the storage wall 20 by climbing over the low height H1 part of the storage wall 20. On the other hand, if the entire storage wall 20 is made high, it becomes difficult to supply the additive into the storage wall 20 by climbing over the top of the storage wall 20, and the additive must pass through the path of the third opening 28h → auxiliary chamber 30 → second opening 22h → outer storage section 24 → first opening 21h → inner storage section 23, which is not preferable.

Furthermore, the boundary where the height of the storage wall 20 changes is the part where the base 28a of the sub-wall portion 28 is connected. This allows a portion of the additive stored in the sub-chamber 30 to be supplied directly to the inner storage portion 23 from the first wall portion 21, which has a reduced height, thereby shortening the supply time of the additive.

The above describes an embodiment of the present invention, but the present invention can be modified as appropriate within the scope of its technical concept. For example, in the above embodiment, the storage wall 20 is provided in a spiral shape, but this is not limited to this shape. Also, in the above embodiment, the storage wall 20 is approximately circular, but this is not limited to this and it may be, for example, elliptical or polygonal. Also, in the above embodiment, the auxiliary wall portion 28 is provided with a bent portion 28c, but this is not limited to this and it may be a straight shape without the bent portion 28c, or a curved shape.

1 Vehicle 2 Side member 3 Rear wheel 5 Axle 4 Cross member 6 Tire wheel (spare tire)
7 Exhaust pipe 8 Muffler 10 Tank

10a Upper member

10b Lower member

10c Connection portion

10d Extension portion 11 Bottom wall 11b Recess 12 Side outer wall

12a Outer wall

12b Inner wall

12c Front wall 12d Rear wall (side wall portion)
13: top wall 18: pump 19: heater 20: storage wall 21: first wall portion 21a: start end 21b: end end 21d: rear wall (first outer side wall)
21h First opening 22 Second wall portion 22h Second opening 221 First opening side portion 221a Left-right direction extending portion 221b Front-rear direction extending portion 222 Second opening side portion 222a End portion 23 Inner storage portion 24 Outer storage portion 25 Front widening portion (widening portion)
26 Rear widening portion (widening portion)
28 Sub-wall portion

28a Base portion

28b Tip portion

28c Bent portion 28d Inclined portion 28e Extension portion 28h Third opening 29 Bracket 29a Mounting hole 30 Sub-chamber 31 Additive injection tube 31a Additive filler 31b Supply port 31c Inlet 32 Leveling tube 33 Vent tube 36 Additive supply tube 36c Delivery port 41 First auxiliary frame 42 Second auxiliary frame 50 Exhaust gas purification device C Center H1, H2 Height

Claims

A tank for storing an additive for purifying exhaust gas from a vehicle,
a pump installed on a bottom wall of the tank for sucking the additive and discharging it to the outside of the tank;
a storage wall that is erected on the bottom wall so as to be spaced apart from a side outer wall of the tank and that surrounds the entire periphery of the pump;
A tank comprising:
The storage wall is
A first wall portion surrounding the pump;
a second wall portion surrounding at least a portion of the first wall portion;
having
An inner storage portion surrounded by the first wall portion and an outer storage portion surrounded by the first wall portion and the second wall portion are formed on the inside of the storage wall.
The tank according to claim 1.
The storage wall is
A first opening connecting the inner reservoir and the outer reservoir;
A second opening connecting the outer reservoir and an area outside the outer reservoir;
having
In a plan view, the first opening and the second opening are arranged so as to be separated by 180° or more in a circumferential direction relative to the center of the inner storage portion.
3. The tank according to claim 2.
the second wall portion has a first opening side portion located on the first opening side and a second opening side portion located on the second opening side,
The outer side wall has a side wall portion adjacent to the second opening side portion,
the second opening side portion is gradually spaced from the side wall portion as it approaches the second opening;
The tank according to claim 3.
The outer storage portion has a widening portion in which a width between the first wall portion and the second wall portion in a plan view is wider than an opening width of the second opening portion in a plan view.
A tank as claimed in claim 3 or 4.
The widening portion is provided in the vicinity of the first opening.
The tank according to claim 5.
The tank further includes a sub-wall portion extending from the bottom wall of the tank to the outside of the storage wall,
The sub-wall portion is disposed opposite the second opening.
A tank as claimed in any one of claims 3 to 6.
The secondary wall portion is connected to an outer surface of the storage wall.
The tank according to claim 7.
the second wall portion has a first opening side portion located on the first opening side and a second opening side portion located on the second opening side,
The outer side wall has a side wall portion adjacent to the second opening side portion,
the sub-chamber wall extends from the outer surface of the storage wall toward the side wall of the tank,
The sub-chamber wall has a bent portion in the middle of its extension such that a tip portion thereof faces the second opening side.
The tank according to claim 8.
the second wall portion has a first opening side portion located on the first opening side and a second opening side portion located on the second opening side,
The outer side wall has a side wall portion adjacent to the second opening side portion,
the sub-wall portion is spaced from the side wall portion of the tank;
A third opening is formed between the sub-wall portion and the side wall portion,
The second opening and the third opening are offset in the vehicle front-rear direction.
A tank as claimed in any one of claims 7 to 9.
The inner reservoir is provided with a heater disposed adjacent to the pump and configured to heat the additive.
A tank according to any one of claims 2 to 10.
The tank has an elongated shape extending in the front-rear direction of the vehicle,
The pump and the storage wall surrounding the pump are disposed on one side of the tank in a vehicle front-rear direction,
The storage wall has a height on one side greater than a height on the other side in the vehicle front-rear direction.
A tank according to any one of claims 1 to 11.
The tank has an elongated shape extending in the front-rear direction of the vehicle,
The pump and the storage wall surrounding the pump are disposed on one side of the tank in a vehicle front-rear direction,
The storage wall has a height on one side in the vehicle front-rear direction greater than a height on the other side, with the portion where the sub-wall portion is connected as a boundary.
The tank according to claim 8.