JP2019027375A - Exhaust emission control device - Google Patents

Abstract

To improve mountability to a vehicle and enhance mixing performance of exhaust gas and a reducing agent in an exhaust emission control device.SOLUTION: An exhaust emission control device 1 includes: a first casing 2 accommodating a filter for collecting particulate matters in exhaust gas in a vehicle 10; a second casing 3 accommodating a selective reduction type catalyst for reducing a constituent in exhaust gas on the downstream side of the first casing 2; an intermediate pipe 4 for communicating the first casing 2 and the second casing 3; and a nozzle 5 for adding a reducing agent into the intermediate pipe 4. The first casing 2 is disposed along a right side member 12 extended in the longitudinal direction. The second casing 3 is disposed along a left side member 11 extended in the longitudinal direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an exhaust emission control device for improving the mountability of an exhaust gas purification filter and a selective reduction catalyst in a vehicle and improving the mixing property of exhaust gas and a reducing agent.

  Conventionally, particulate matter (PM) contained in diesel engine exhaust is collected by a filter (DPF; DieselParticulate Filter) and a reducing agent is added to the exhaust to select nitrogen oxide (NOx) in the exhaust. 2. Description of the Related Art An exhaust gas purification device that removes by a reducing catalyst (SCR: Selective Catalytic Reduction) is known.

  In order to realize the space saving of such an exhaust purification device, Patent Document 1 discloses that two cylindrical casings (casings) each housing DPF and SCR so that their axes are substantially parallel to each other. It has been proposed to place them in close proximity to each other and to connect the far ends of these cases with a communication pipe (intermediate pipe).

  According to the technique of Patent Document 1, it is said that a compact form in which the communication pipe is accommodated in the silhouettes of the two housings can be realized. Further, since the length of the communication pipe can be obtained, it is said that the reducing agent injected into the communication pipe can be uniformly diffused.

JP 2009-85064 A

  However, depending on the configuration of the vehicle, it may not be possible to secure a space for arranging the casing containing the DPF and the casing containing the SCR close to each other. Even if these casings can be arranged close to each other, the arrangement space for the intermediate pipes connecting the casings is limited, so that the shape of the intermediate pipes may be complicated and the exhaust gas and the reducing agent may not be mixed well. is there.

  The exhaust purification device of the present invention has been devised in view of the above-described problems, and an object thereof is to improve the mounting property on a vehicle and to improve the mixing property of exhaust gas and a reducing agent.

  (1) An exhaust emission control device disclosed herein is for a first casing that houses a filter that collects particulate matter in exhaust gas in a vehicle, and for reducing components in the exhaust gas downstream of the first casing. An exhaust emission control device comprising: a second casing containing a selective reduction catalyst; an intermediate pipe communicating the first casing and the second casing; and a nozzle for adding a reducing agent into the intermediate pipe. The first casing is disposed along one of the left and right side members extending in the front-rear direction, and the second casing is disposed along the other of the left and right side members. It is said. Thereby, the arrangement space of the first casing and the second casing can be shortened in the front-rear direction, and the length of the intermediate pipe in the left-right direction is ensured.

(2) The intermediate pipe is arranged above the propeller shaft extending in the front-rear direction and straddles the propeller shaft, and the bent portion is bent downward from both ends of the straddle portion. It is preferable to have. In this case, the intermediate pipe has a shape that easily bypasses the propeller shaft, and the turbulent flow is easily generated in the exhaust gas by changing the flow direction of the exhaust gas by the bent portion.

  According to the disclosed exhaust emission control device, it is possible to improve the mounting property on a vehicle and to improve the mixing property of the exhaust gas and the reducing agent.

1 is a bottom view of a vehicle equipped with an exhaust emission control device according to an embodiment. It is a perspective view which shows the exhaust gas purification apparatus of FIG. 1 with a propeller shaft. FIG. 2 is a schematic diagram for explaining a positional relationship between an intermediate pipe and a propeller shaft of the exhaust purification device of FIG. 1.

  An exhaust emission control device as an embodiment will be described with reference to the drawings. The embodiment described below is merely an example, and there is no intention of excluding various modifications and technical applications that are not explicitly described in the following embodiment.

[1. Constitution]
An exhaust emission control device 1 according to this embodiment is applied to a vehicle 10 shown in FIG. The vehicle 10 is a bus, for example, and has a ladder-type body frame.

  The vehicle body frame of the vehicle 10 includes left and right side members 11 and 12 extending in the front-rear direction, and a plurality of cross members 13 to 18 installed between the side members 11 and 12. The side members 11 and 12 are spaced apart from each other in the left-right direction. Moreover, the cross members 13-18 are arrange | positioned mutually spaced apart in the front-back direction.

  Between the left and right side members 11, 12, there are an engine 21 that is a drive source of the vehicle 10, a transmission 22 for changing the output rotation torque, rotation speed, and rotation direction of the engine 21, and a transmission 22. A propeller shaft 24 and a differential device 25 for transmitting output rotation to the left and right rear wheels 23, 23 are arranged.

  The engine 21 is mounted between the left and right front wheels 26 and 26 of the vehicle 10. Further, the transmission 22 is disposed adjacent to the rear of the engine 21. Further, the propeller shaft 24 extends from the rear end portion of the transmission 22 toward the differential device 25 in the front-rear direction at substantially the center in the left-right direction of the vehicle 10. The differential 25 is disposed between the left and right rear wheels 23 and 23. The output rotation of the engine 21 is distributed to the left and right rear wheels 23 and 23 through the transmission 22, the propeller shaft 24, and the differential device 25 in this order.

  The exhaust purification device 1 is for purifying exhaust (combustion gas) of the engine 21 and is interposed in the exhaust passage of the engine 21. Specifically, the exhaust purification device 1 includes a DPF (filter) that collects PM in exhaust gas, and an SCR (selective reduction catalyst) for reducing NOx (component) in exhaust gas downstream of the DPF. Use to detoxify the exhaust.

The exhaust emission control device 1 includes a DPF casing (first casing) 2 containing DPF, an SCR casing (second casing) 3 containing SCR, an intermediate pipe 4 connecting these casings 2, 3, The pipe 4 includes a nozzle 5 for adding urea water (reducing agent). The exhaust gas is collected in the DPF casing 2 by DPF and then mixed with urea water injected from the nozzle 5 in the process of flowing through the intermediate pipe 4, and ammonia generated by hydrolysis of the urea water is used as a reducing agent. NOx is reduced and removed by the SCR in the SCR casing 3. Then, the gas is discharged to the outside of the vehicle 10 through the exhaust pipe 27 connected to the downstream end of the SCR casing 3.

  Both the DPF casing 2 and the SCR casing 3 are formed in a cylindrical shape. In this embodiment, the case where the DPF casing 2 is disposed along the right side member 12 and the SCR casing 3 is disposed along the left side member 11 is illustrated. The DPF casing 2 and the SCR casing 3 are provided apart from each other in the left-right direction. A propeller shaft 24 is located between the DPF casing 2 and the SCR casing 3.

  The DPF casing 2 of this embodiment is disposed in front of the SCR casing 3. That is, the rear end portion 2 a of the DPF casing 2 is positioned in front of the front end portion 3 a of the SCR casing 3. The DPF casing 2 is fixed to the right side member 12 via a bracket (not shown). Similarly, the SCR casing 3 is fixed to the left side member 11 via a bracket (not shown).

  Note that the DPF casing 2 of the present embodiment is mounted in a posture in which its axis is slightly inclined with respect to the front-rear direction so as to be positioned as far as possible while avoiding interference with the transmission 22. On the other hand, the SCR casing 3 is mounted in a posture in which the axis is along the front-rear direction (that is, in a posture parallel to the left side member 11). In the present embodiment, the case where both the DPF casing 2 and the SCR casing 3 are arranged in a region inside the left and right side members 11 and 12 is illustrated. However, at least one of the DPF casing 2 and the SCR casing 3 You may arrange | position in the area | region outside the left and right side members 11 and 12. FIG.

  The intermediate pipe 4 forms an exhaust passage from the DPF casing 2 to the SCR casing 3, and communicates the rear end portion 2 a of the DPF casing 2 and the front end portion 3 a of the SCR casing 3. As shown in FIG. 2, the intermediate pipe 4 of the present embodiment includes an addition portion 4 a where the nozzle 5 is disposed, a straddling portion 4 b disposed above the propeller shaft 24 and straddling the propeller shaft 24, and straddling It has bending parts 4c and 4d provided on both sides of the part 4b.

  The addition part 4a is a part extending rearward from the DPF casing 2. The nozzle 5 of the present embodiment is attached to a substantially intermediate portion in the front-rear direction of the adding portion 4a. The straddling portion 4b is formed downstream of the adding portion 4a. The straddling portion 4b is the highest part (located on the upper side) in the intermediate pipe 4. In this embodiment, the case where the extending portion 4b extends in the left-right direction and is substantially orthogonal to the propeller shaft 24 in a top view or a bottom view is illustrated.

  The bent portions 4c and 4d are portions bent downward from both left and right ends of the extending portion 4b. One bending part 4c is provided between the addition part 4a and the straddling part 4b. The other bent portion 4 d is provided between the straddling portion 4 b and the upstream end 3 a of the SCR casing 3.

  As shown in FIG. 3, when the intermediate pipe 4 is viewed in the front-rear direction, the straddling portion 4b and the bent portions 4c, 4d form a C-shape that opens downward. The straddling portion 4 b and the bent portions 4 c and 4 d are arranged so as to surround the propeller shaft 24. That is, the intermediate pipe 4 is extended by the straddling portion 4b and the bent portions 4c and 4d so as to bypass the propeller shaft 24 from the upper side.

[2. Action, effect]
(1) According to the exhaust purification device 1 described above, the DPF casing 2 is disposed along the right side member 12 and the SCR casing 3 is disposed along the left side member 11. The space in the direction can be saved, and the length of the intermediate pipe 4 can be secured. That is, as shown in FIG. 1, the DPF casing 2 and the SCR casing 3 are arranged so as to be shifted to the left and right, so that the distance d in the front-rear direction of the DPF casing 2 and the SCR casing 3 can be kept short. The path length can be secured long in the left-right direction.

  For this reason, according to the exhaust emission control device 1, it is possible to improve the mountability to the vehicle 10, and it is possible to improve the mixing property of urea water and exhaust gas in the intermediate pipe 4. Moreover, since the mounting property to the vehicle 10 is improved in this way, it becomes possible to share the exhaust purification device 1 even in a vehicle type having a different wheel base, for example. Therefore, it can contribute to cost reduction.

  (2) Since the intermediate pipe 4 has the extending portion 4b disposed above the propeller shaft 24 and the bent portions 4c and 4d bent downward from both ends of the extending portion 4b, the intermediate pipe 4 While preventing the interference with the propeller shaft 24, the intermediate pipe 4 can be made difficult to interfere with the road surface.

  If the intermediate pipe 4 is bent downward and the propeller shaft 24 is detoured, the intermediate pipe 4 is close to the road surface, so that it easily interferes with the road surface. On the other hand, if the intermediate pipe 4 has the above-described straddling portion 4b and bent portions 4c and 4d, the propeller shaft 24 can be bypassed at a position where the intermediate pipe 4 is away from the road surface. Therefore, it can contribute to protection of the intermediate pipe 4.

  Further, by providing the bent portions 4c and 4d downstream of the adding portion 4a of the intermediate pipe 4, the path length of the intermediate pipe 4 can be made longer and the flow direction of the exhaust gas along the bent portions 4c and 4d. Can be made easy to produce turbulent flow. Thereby, mixing with exhaust_gas | exhaustion and urea water can be accelerated | stimulated.

[3. Modified example]
Regardless of the embodiment described above, various modifications can be made without departing from the spirit of the invention. Each structure of this embodiment can be selected as needed, or may be combined appropriately.

  For example, when the exhaust outlet from the engine 21 is on the left side of the engine 21, the DPF casing 2 is disposed along the left side member 11 symmetrically with the above-described arrangement, and the SCR casing 3 is on the right side. It may be disposed along the side member 12. Further, the rear end portion 2 a of the DPF casing 2 may be located behind the front end portion 3 a of the SCR casing 3. That is, the DPF casing 2 and the SCR casing 3 may be arranged so as to be wrapped in the front-rear direction.

  The configuration of the intermediate pipe 4 described above is an example. The intermediate pipe 4 only needs to communicate at least the DPF casing 2 and the SCR casing 3, and the above-described straddling portion 4b and the bent portions 4c and 4d may be omitted.

  The reducing agent added by the nozzle 5 is not limited to urea water. Moreover, the attachment position of the nozzle 5 is not limited to the position mentioned above. For example, the nozzle 5 may be attached to the upstream end portion of the addition portion 4 a or may be attached to a portion other than the addition portion 4 a of the intermediate pipe 4.

1 Exhaust purification device 2 DPF casing (first casing)
2a Rear end 3 SCR casing (second casing)
3a Front end portion 4 Intermediate pipe 4a Addition portion 4b Stretched portion 4c, 4d Bending portion 5 Nozzle 10 Vehicle 11 Left side member 12 Right side member 13-18 Cross member 21 Engine 22 Transmission 23 Rear wheel 24 Propeller shaft 25 Difference Moving device 26 Front wheel 27 Exhaust pipe d Distance

Claims (2)

A first casing containing a filter for collecting particulate matter in exhaust in a vehicle; a second casing containing a selective catalytic reduction catalyst for reducing components in the exhaust downstream of the first casing; An exhaust purification device comprising an intermediate pipe communicating the first casing and the second casing, and a nozzle for adding a reducing agent into the intermediate pipe,
The first casing is disposed along one of the left and right side members extending in the front-rear direction, and the second casing is disposed along the other of the left and right side members. Exhaust purification device. The intermediate pipe has a straddle portion that is disposed above the propeller shaft extending in the front-rear direction and straddles the propeller shaft, and a bent portion that is bent downward from both ends of the straddle portion. The exhaust emission control device according to claim 1, wherein

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