WO2011068054A1

WO2011068054A1 - Exhaust purification device

Info

Publication number: WO2011068054A1
Application number: PCT/JP2010/070813
Authority: WO
Inventors: 宏至竹内; 理恵子榊原; 久宜加藤; 一紀中村; 高晴永利; 慶祐安仲; 篤木全; 洋一外山; 貴幸宮里; 大五郎渡辺
Original assignee: トヨタ自動車株式会社
Priority date: 2009-12-01
Filing date: 2010-11-22
Publication date: 2011-06-09
Also published as: CN102630269A; JP2011117328A; BR112012012363A2; JP5381661B2; CN102630269B

Abstract

Disclosed is an exhaust purification device provided in an internal combustion engine, comprising an exhaust pipe, an exhaust purification catalyst, and an exhaust guide portion. The exhaust pipe extends downward from the front side portion of the internal combustion engine, and has a downstream port. The exhaust purification catalyst extends below the internal combustion engine in the longitudinal direction of a vehicle. The exhaust guide portion connects the downstream port to the front end of the exhaust purification catalyst so that the central axis of the exhaust pipe is inclined with respect to the central axis of the exhaust purification catalyst. The exhaust guide portion connects the downstream port to the front end of the exhaust purification catalyst so that at least a part of an extended portion obtained when the downstream port is extended toward the downstream side, abuts with the lower portion of the inner surface of the exhaust guide portion. An expanded portion that expands toward the front side of a vehicle is formed at the portion of the exhaust guide portion, which is located at the front of the extended portion in the vehicle.

Description

Exhaust purification device

The present invention relates to an exhaust purification device.

Vehicles such as automobiles are provided with an exhaust purification device for purifying exhaust gas from an internal combustion engine. As such an exhaust purification device, as shown in FIG. 9, an exhaust pipe 102 extending downward from a front portion of the internal combustion engine 101, an exhaust purification catalyst 104 extending below the engine 101 in the front-rear direction of the vehicle, An exhaust pipe having a downstream port 103 of the exhaust pipe 102 and an exhaust guide 105 connecting the front end of the exhaust purification catalyst 104 is known. In the drawing, “front” and “rear” correspond to the front side and the rear side of the vehicle, respectively. Exhaust gas discharged from the internal combustion engine 101 to the exhaust pipe 102 flows into the exhaust guide portion 105 via the downstream port 103 of the exhaust pipe 102 and further flows into the exhaust purification catalyst 104 from its front end. It is released into the atmosphere after being purified in

The exhaust purification catalyst 104 is provided as close to the front side of the vehicle as possible (upstream in the exhaust flow direction), and the exhaust purification catalyst 104 is heated by the heat of the exhaust so that high-temperature exhaust flows into the exhaust purification catalyst 104. The effective warm-up of is planned. On the other hand, the exhaust pipe 102 that guides the exhaust of the internal combustion engine 101 to the exhaust purification catalyst 104 projects from the front of the internal combustion engine 101 because the exhaust of the internal combustion engine 101 is exhausted from the engine 101 toward the front of the vehicle. It extends downward along the front surface. The exhaust guide portion 105 is formed in a shape bent approximately 90 ° so that the downstream port 103 of the exhaust pipe 102 can be connected to the front end of the exhaust purification catalyst 104.

However, if the exhaust guide portion 105 is bent by approximately 90 ° as described above, the exhaust flowing from the downstream port 103 of the exhaust pipe 102 toward the front end of the exhaust purification catalyst 104 via the exhaust guide portion 105 is the same exhaust gas. Flows through the lower part of the exhaust guide part 105 mainly as indicated by the arrows in the figure. As a result, most of the exhaust gas that has reached the exhaust purification catalyst 104 through the exhaust guide portion 105 flows into the catalyst 104 from the lower half of the front end face of the exhaust purification catalyst 104. Thus, if the inflow of exhaust gas from the front end surface of the exhaust purification catalyst 104 is biased to the lower half of the front end surface, it becomes difficult to effectively purify the exhaust gas at the exhaust purification catalyst 104.

Further, in order to perform the inflow of exhaust gas from the front end surface of the exhaust purification catalyst uniformly over the entire front end surface, for example, Patent Document 1 discloses the configuration shown in [1] to [3] below in the exhaust purification device. Employment is disclosed.
[1] The central axis of the exhaust pipe connected to the exhaust guide portion is inclined with respect to the central axis of the exhaust purification catalyst, and the inclination angle is set to a small value of less than 45 °.
[2] In the range where the extension portion when the downstream port of the exhaust pipe connected to the exhaust guide portion is extended does not deviate from the front end face of the exhaust purification catalyst, the central axis of the exhaust pipe is relative to the center of the front end face of the exhaust purification catalyst. An exhaust pipe is provided so as to be offset in the inclination direction.
[3] A bulging portion that is curved to bulge outward is formed on the opposite side of the exhaust guide portion from the inclination direction.

In the exhaust emission control device of Patent Document 1, by adopting such a configuration of [1] to [3], it is possible to uniformly flow in exhaust gas from the front end face of the exhaust purification catalyst over the entire front end face. Yes.

Therefore, if the configurations [1] to [3] in Patent Document 1 are applied to the exhaust purification device of FIG. 9, the inflow of exhaust gas from the front end face of the exhaust purification catalyst 104 is biased to the lower half of the front end face. It is considered that the problem that it becomes difficult to effectively purify the exhaust gas by the exhaust purification catalyst 104 due to the fact that it is performed can be solved. Here, FIGS. 10 and 11 show application examples of the above-described configurations [1] to [3] for the exhaust emission control device of FIG. In the example of FIG. 10, the arrangements [1] to [3] can be realized by arranging the exhaust purification catalyst 104 so as to be inclined upward. In the example of FIG. 11, the downstream end of the exhaust pipe 102 is formed so as to extend obliquely toward the rear side and the lower side of the vehicle with a tilt angle of less than 45 ° with respect to the horizontal plane. The configurations 1] to [3] can be realized.

JP 2004-332607 A (paragraphs [0024] to [0032], FIGS. 3 to 5)

By the way, in FIG. 10 and FIG. 11 which are application examples of the configurations [1] to [3] to the exhaust purification apparatus, the exhaust purification catalyst 104 is inclined to the front rising state in the example of FIG. It is highly likely that the exhaust purification catalyst 104 will not fit between the lower part of the internal combustion engine 101 and the road surface, so this example cannot be actually used. On the other hand, in the example of FIG. 11, the exhaust purification catalyst 104 can be arranged so as to extend in the front-rear direction (horizontal direction), so that the exhaust purification catalyst 104 does not fit completely between the lower part of the internal combustion engine 101 and the road surface. Absent. However, in this example, in order to realize the configurations [1] and [2], the downstream end portion of the exhaust pipe 102 must be extended toward the rear side of the vehicle. As a result, the exhaust purification catalyst 104 must be arranged on the downstream side (rear side of the vehicle) in the exhaust flow direction, and it is difficult to effectively warm up the exhaust purification catalyst 104 by the exhaust of the internal combustion engine 101. become.

An object of the present invention is to provide an exhaust gas that can uniformly flow in exhaust gas from the front end face of the exhaust purification catalyst over the entire front end face without shifting the position of the exhaust purification catalyst downstream in the exhaust flow direction. It is to provide a purification device.

In order to achieve the above object, according to one aspect of the present invention, an exhaust emission control device provided in an internal combustion engine mounted on a vehicle is provided. The exhaust purification device includes an exhaust pipe, an exhaust purification catalyst, and an exhaust guide. The exhaust pipe extends downward from a front portion of the internal combustion engine and has a downstream port. The exhaust purification catalyst extends in the front-rear direction of the vehicle below the internal combustion engine. The exhaust guide unit connects the downstream port to the front end of the exhaust purification catalyst so that the central axis of the exhaust pipe is inclined with respect to the central axis of the exhaust purification catalyst. The exhaust guide portion connects the downstream port and the front end of the exhaust purification catalyst so that at least a part of an extended portion obtained when the downstream port is extended to the downstream side hits a lower portion of the inner surface of the exhaust guide portion. . In the exhaust guide portion, a bulging portion that bulges toward the front of the vehicle is formed in a portion on the front side of the vehicle with respect to the extended portion.

1 is a diagram schematically illustrating an internal combustion engine to which an exhaust emission control device according to an embodiment of the present invention is applied and an exhaust system thereof. The side view which shows the external shape of the exhaust guide part of FIG. The front view which shows the external shape of the exhaust guide part of FIG. The figure which shows typically the state which looked at the inside of the exhaust guide part of FIG. 1 from the side. The figure which shows typically the state which looked at the inside of the exhaust guide part of FIG. 1 from the front side front. The figure which shows the flow of the exhaust_gas | exhaustion in the inside of the exhaust guide part of FIG. The figure which shows the flow of the exhaust_gas | exhaustion in the inside of the exhaust guide part of FIG. The figure which shows the other example of an exhaust guide part. The figure which shows typically the internal combustion engine to which the conventional exhaust gas purification apparatus is applied, and its exhaust system. The figure which shows typically the internal combustion engine to which the conventional exhaust gas purification apparatus is applied, and its exhaust system. The figure which shows typically the internal combustion engine to which the conventional exhaust gas purification apparatus is applied, and its exhaust system.

Hereinafter, an embodiment in which the present invention is embodied in an exhaust emission control device for purifying exhaust gas of an internal combustion engine mounted on an automobile will be described with reference to FIGS. In the figure, “front” and “rear” correspond to the front side and the rear side of the automobile, respectively.

FIG. 1 schematically shows an internal combustion engine 1 mounted on an automobile and its exhaust system. The internal combustion engine 1 includes an exhaust pipe 2 that extends downward from a front portion (left portion in the figure) of the internal combustion engine 1. In the exhaust pipe 2, an exhaust purification catalyst 3 is provided in the middle of the pipe line so as to extend in the vertical direction. An exhaust guide portion 6 is connected to the downstream port 4 of the exhaust pipe 2, and the exhaust guide portion 6 has a front end of an exhaust purification catalyst 5 that extends in the front-rear direction of the automobile (left-right direction in the figure) below the internal combustion engine 1. It is connected. In other words, the front end of the exhaust purification catalyst 5 is connected to the downstream port 4 of the exhaust pipe by the exhaust guide portion 6.

The exhaust purification device provided in the automobile to purify the exhaust gas of the internal combustion engine 1 includes the exhaust purification catalyst 5, the exhaust guide portion 6 and the like. In an automobile provided with such an exhaust purification device, the exhaust gas emitted from the internal combustion engine 1 to the exhaust pipe 2 is purified by the exhaust purification catalyst 3, and then the exhaust guide section 6 via the downstream port 4 of the exhaust pipe 2. , Further flows into the exhaust purification catalyst 5 from its front end, and after being purified by the exhaust purification catalyst 5, is discharged into the atmosphere. Further, in the exhaust purification apparatus, the exhaust gas is exhausted in order to allow warm exhaust gas to flow into the exhaust purification catalyst 5 located downstream of the exhaust purification catalyst 3 and to effectively warm up the catalyst 5 with the heat of the exhaust gas. The purification catalyst 5 is provided on the upstream side in the exhaust flow direction as much as possible. However, since the exhaust purification catalyst 3 is provided on the front side of the internal combustion engine 1, the exhaust purification catalyst 5 is provided on the lower side of the internal combustion engine 1 as close to the front side of the automobile as possible.

Next, the detailed structure of the exhaust guide 6 that connects the downstream port 4 of the exhaust pipe 2 and the front end of the exhaust purification catalyst 5 will be described with reference to FIGS. FIG. 2 is a side view of the exhaust guide portion 6, and FIG. 3 is a front view of the exhaust guide portion 6. FIG. 4 schematically shows a state in which the inside of the exhaust guide portion 6 is viewed from the side, and FIG. 5 schematically shows a state in which the inside of the exhaust guide portion 6 is viewed from the front side in front. Is.

The outer shape of the exhaust guide 6 is the shape shown in FIGS. The exhaust guide portion 6 connects the downstream port 4 of the exhaust pipe 2 and the front end of the exhaust purification catalyst 5 so as to realize the following configurations [a] to [c].
[A] As shown in FIG. 4, the central axis C1 of the exhaust pipe 2 is inclined with respect to the central axis C2 of the exhaust purification catalyst 5 (including 90 °), and more specifically, the internal combustion engine 1 is sandwiched. Thus, the inclination angle θ formed by the central axis C1 and the central axis C2 is set to a value within the range of 45 to 135 °.
[B] As shown in FIG. 4, at least a part (all in this example) of the extended portion obtained when the downstream port 4 of the exhaust pipe 2 is extended downstream as shown by the broken line in the figure, It hits the lower part of the inner surface of the exhaust guide 6.
[C] As shown in FIG. 5, the central axis C <b> 1 of the exhaust pipe 2 is positioned away from the central axis C <b> 2 of the exhaust purification catalyst 5 in the horizontal direction.

As shown in FIG. 4, in the exhaust guide portion 6, a portion on the front side of the vehicle with respect to the extended portion (broken line in the drawing) of the downstream port 4 of the exhaust pipe 2 swells toward the front of the vehicle. A curved bulging portion 7 is formed.

Next, the flow of exhaust flowing from the exhaust pipe 2 to the exhaust purification catalyst 5 via the exhaust guide 6 will be described with reference to FIGS. 6 schematically shows a state of the inside of the exhaust guide portion 6 viewed from the side, and FIG. 7 schematically shows a state of the inside of the exhaust guide portion 6 viewed from the front side. Is.

As shown in FIG. 6, the exhaust gas that has entered the exhaust guide portion 6 from the downstream port 4 of the exhaust pipe 2 hits the lower inner surface of the exhaust guide portion 6, and is divided into the rear side and the front side of the automobile, and is divided into the rear side. The exhausted gas flows into the catalyst 5 from the lower half of the front end face of the exhaust purification catalyst 5. On the other hand, the exhaust gas that has flowed to the front side flows forward along the inner surface of the bulging portion 7 of the exhaust guide portion 6, and turns to the upper side and further to the rear side by the inner surface to change the direction of the front end surface of the exhaust purification catalyst 5. It flows into the catalyst 5 from the upper half. The inner surface of the bulging portion 7 and the upper inner surface of the exhaust guide portion 6 are curved so that the exhaust gas flowing along them is smoothly guided to the upper half of the exhaust purification catalyst 5.

The amount of exhaust gas that splits into the rear side of the vehicle after the exhaust gas that has entered the exhaust guide unit 6 from the downstream port 4 of the exhaust pipe 2 hits the lower inner surface of the exhaust guide unit 6 and the amount of exhaust gas that flows into the front side of the vehicle This ratio varies depending on the inclination angle θ formed by the central axis C1 and the central axis C2 with the internal combustion engine 1 in between. Incidentally, the inclination angle θ in this example is a value within the range of 45 to 135 ° described above, and the amount of exhaust gas diverted to the rear side of the vehicle is equal to the amount of exhaust gas diverted to the front side of the vehicle. A value (for example, 95 °) is set.

Further, as shown in FIG. 7, the central axis C1 of the exhaust pipe 2 is located away from the central axis C2 of the exhaust purification catalyst 5 in the horizontal direction. Exhaust gas that has entered the interior of the exhaust gas 6 and then diverted to the front side of the automobile by hitting the inside of the lower surface of the exhaust gas guide 6 flows as indicated by an arrow Y in FIG. That is, the exhaust gas draws a spiral trajectory around the central axis C <b> 2 of the exhaust purification catalyst 5 when flowing forward along the inner surface of the bulging portion 7 (FIG. 6) of the exhaust guide portion 6. . Thereby, it is suppressed that the flow of the exhaust gas diverted to the front side of the automobile interferes with the flow of exhaust gas that enters the exhaust guide portion 6 from the downstream port 4 of the exhaust pipe 2.

According to the embodiment described above in detail, the following advantages can be obtained.
(1) The exhaust pipe 2 is arranged so that an extended portion (broken line in FIG. 4) obtained when the downstream port 4 of the exhaust pipe 2 is extended is detached from the front end face of the exhaust purification catalyst 5 toward the front side of the automobile. As a result, the central axis C1 of the exhaust pipe 2 is made to stand with respect to the central axis C2 of the exhaust purification catalyst 5. In such a configuration, the exhaust purification catalyst is shifted toward the rear side of the vehicle so that the downstream end portion of the exhaust pipe is laid down with respect to the central axis of the exhaust purification catalyst as in the prior art (see FIG. 11). There is no need. Further, the exhaust gas that has entered the exhaust guide portion 6 from the downstream port 4 of the exhaust pipe 2 hits the lower inner surface of the exhaust guide portion 6 and is divided into the rear side and the front side of the automobile. 5 flows into the catalyst 5 from the lower half of the front end face. On the other hand, the exhaust gas that has flowed to the front side flows forward along the inner surface of the bulging portion 7 of the exhaust guide portion 6, and turns to the upper side and further to the rear side by the inner surface to change the direction of the front end surface of the exhaust purification catalyst 5. It flows into the catalyst 5 from the upper half. For this reason, it is possible to prevent the exhaust purification catalyst 5 from being biased in the exhaust purification catalyst 5 such that the exhaust gas flows only from the lower half of the front end face thereof. As described above, the inflow of exhaust gas from the front end surface of the exhaust purification catalyst 5 is made uniform over the entire front end surface without shifting the position of the exhaust purification catalyst 5 to the downstream side (rear side of the automobile) in the exhaust flow direction. Will be able to do.

(2) Exhaust gas that has entered the exhaust guide portion 6 from the downstream port 4 of the exhaust pipe 2 hits the lower inner surface of the exhaust guide portion 6 and is divided into the rear side and the front side of the vehicle. When flowing forward along the inner surface of the bulging portion 7 of the portion 6, a spiral locus is drawn around the central axis C <b> 2 of the exhaust purification catalyst 5. This is because the central axis C1 of the exhaust pipe 2 is located away from the central axis C2 of the exhaust purification catalyst 5 in the horizontal direction. Then, as the exhaust gas diverted to the front side of the automobile flows in a spiral locus as described above, the exhaust gas bypasses the flow of the exhaust gas that enters the exhaust guide portion 6 from the downstream port 4 of the exhaust pipe 2. And will begin to flow. As a result, it is possible to suppress the flow of the exhaust gas diverted to the front side of the automobile from interfering with the flow of exhaust gas entering the exhaust guide portion 6 from the downstream port 4 of the exhaust pipe 2, and the exhaust gas diverted to the front side of the automobile is It becomes possible to flow toward the upper half of the front end face of the exhaust purification catalyst 5 efficiently.

(3) By setting the inclination angle θ of the central axis C1 of the exhaust pipe 2 with respect to the central axis C2 of the exhaust purification catalyst 5 to a value within the range of 45 ° to 135 °, exhaust from the downstream port 4 of the exhaust pipe 2 When this flow hits the lower inner surface of the exhaust guide section 6, it is possible to suppress the amount of exhaust flowing to the front side of the automobile or the amount of exhaust flowing to the rear side of the automobile from being excessively reduced. Therefore, the amount of exhaust gas flowing into the catalyst 5 from the upper half of the front end surface of the exhaust purification catalyst 5 is excessively reduced, or the exhaust gas flowing into the catalyst 5 from the lower half of the front end surface of the exhaust purification catalyst 5. It can suppress that the quantity of becomes too small.

(4) More specifically, the inclination angle θ is a value within the range of 45 ° to 135 ° described above, and the flow of exhaust from the downstream port 4 of the exhaust pipe 2 is below the exhaust guide 6. A value (95 ° in this example) is set so that the amount of exhaust gas diverted to the rear side of the vehicle and the amount of exhaust gas diverted to the front side of the vehicle when hitting the inner surface are equal. For this reason, the amount of exhaust gas that flows into the rear side of the automobile and flows into the catalyst 5 from the lower half at the front end portion of the exhaust purification catalyst 5 is the same as that from the upper half of the exhaust purification catalyst 5 that flows into the front side of the automobile. The amount of exhaust gas flowing into the catalyst 5 becomes equal. Therefore, the inflow of exhaust gas from the front end surface of the exhaust purification catalyst 5 can be performed more accurately and uniformly over the entire front end surface.

In addition, the said embodiment can also be changed as follows, for example.
As shown in FIG. 8, on the inner surface of the exhaust guide portion 6, it protrudes toward the downstream port 4 at a position overlapping with an extended portion (broken line) obtained when the downstream port 4 of the exhaust pipe 2 is extended downstream. You may form the diversion part 8 which diverts a part of exhaust_gas | exhaustion which flows from the downstream port 4 to the front side (left side in a figure) of a motor vehicle.

According to this configuration, by adjusting the inclination or the like of the flow dividing portion 8 with respect to the flow direction of the exhaust gas from the downstream port 4 of the exhaust pipe 2, It is possible to appropriately adjust the amount of exhaust flowing to the front side of the vehicle and the amount of exhaust flowing to the rear side of the vehicle. Therefore, the adjustment of the exhaust amount can be performed more finely and accurately by adjusting by the flow dividing section 8 together with the adjustment by the inclination angle θ. In addition, when it is going to change the said inclination-angle (theta), it will be inevitable that the influence on arrangement | positioning etc. of other components by the change will become large. In the configuration including the flow dividing section 8, the amount of exhaust gas flowing to the front side of the automobile and the amount of exhaust gas flowing to the rear side of the automobile are adjusted only by adjusting the inclination of the flow dividing section 8 while fixing the inclination angle θ. It is also possible to prevent the change of the tilt angle θ from causing a great influence on the arrangement of other components.

The range of 45 to 135 ° is exemplified as the range of the inclination angle θ, but a more preferable range is 70 to 120 °, and the most preferable range is 80 to 110 °.

As an example of setting the inclination angle θ, 95 ° has been described, but this value can be changed as appropriate.
The exhaust guide portion 6 includes the downstream port 4 of the exhaust pipe 2 and the exhaust purification catalyst so that a part of the extended portion obtained when the downstream port 4 of the exhaust pipe 2 is extended to the downstream side hits the lower part of the inner surface of the exhaust guide portion 6. 5 may be connected to the front end.

Claims

In an exhaust emission control device provided in an internal combustion engine mounted on a vehicle,
An exhaust pipe extending downward from a front portion of the internal combustion engine and having a downstream port;
An exhaust purification catalyst extending in the longitudinal direction of the vehicle below the internal combustion engine;
An exhaust guide that connects the downstream port to the front end of the exhaust purification catalyst so that the central axis of the exhaust pipe is inclined with respect to the central axis of the exhaust purification catalyst;
The exhaust guide part connects the downstream port and the front end of the exhaust purification catalyst so that at least a part of the extension obtained when the downstream port is extended downstream is in contact with the lower part of the inner surface of the exhaust guide part. ,
In the exhaust guide portion, an exhaust purification device in which a bulge portion that bulges toward the front of the vehicle is formed in a portion on the front side of the vehicle with respect to the extended portion.
2. The exhaust guide portion connects the downstream port and a front end of the exhaust purification catalyst so that a central axis of the exhaust pipe is positioned in a horizontal direction with respect to a central axis of the exhaust purification catalyst. Exhaust purification equipment.
The inclination angle of the center axis of the exhaust pipe with respect to the center axis of the exhaust purification catalyst is divided into the rear side of the vehicle when the exhaust gas that has entered the exhaust guide portion from the downstream port hits the lower inner surface of the exhaust guide portion. The exhaust emission control device according to claim 1, wherein the exhaust purification device is set to a value at which an amount of exhaust gas to be discharged and an exhaust gas flow to the front side of the vehicle are equal.
The flow dividing portion that projects toward the downstream port and diverts a part of the exhaust flowing from the downstream port to the front side of the vehicle is formed at a position overlapping the extended portion on the inner surface of the exhaust guide portion. Exhaust gas purification device described in 1.
The exhaust purification device according to claim 1, wherein an inclination angle formed by a central axis of the exhaust purification catalyst and a central axis of the exhaust pipe across the internal combustion engine is a value within a range of 45 ° to 135 °. .