JP2006329031A - Turbocharged internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine with a turbocharger capable of improving exhaust efficiency in the internal combustion engine with the turbocharger. <P>SOLUTION: An expanded pipe part (40) is formed near an exhaust downstream side of the turbocharger (20). The expanded pipe part comprises a hollow area (40a) and an outer peripheral area (40b) and a flow straightening plate (42) is provided in the outer peripheral area. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an internal combustion engine with a turbocharger, and more particularly to a technique for improving exhaust efficiency downstream of the turbocharger.

As a means for improving the performance of an internal combustion engine (hereinafter referred to as an engine), a turbocharger that supercharges intake air by rotating a compressor synchronously by rotating a turbine using exhaust energy is generally used.
In an engine equipped with such a turbocharger, in the exhaust system, a strong vortex is generated in the exhaust downstream of the turbine due to the rotation of the turbine, and the exhaust drifts to the outer peripheral side of the exhaust passage due to the centrifugal force of the vortex. Therefore, there arises a problem that the exhaust efficiency is lowered such as a decrease in flow velocity in the exhaust transport direction and an increase in exhaust resistance. In addition, when exhaust purification means such as a catalyst is provided downstream of the turbine, if the exhaust gas flows into the exhaust purification means in a non-uniform state, exhaust purification performance cannot be fully exhibited and purification efficiency is reduced. There is also a problem that it falls.

In view of this, a technology is disclosed that rectifies the swirled exhaust gas and flows into the catalyst in a configuration in which the exhaust pipe downstream of the turbine has a bent portion and the catalyst is provided immediately below the bent portion on the exhaust downstream side. (See Patent Document 1).
JP 2003-49640 A

However, in the technique disclosed in Patent Document 1, since the rectifying plate is provided at the bent portion, the exhaust resistance at the bent portion increases, so that the exhaust pressure increases and the exhaust efficiency of the engine decreases. There is.
The present invention has been made to solve such problems, and an object of the present invention is to provide an internal combustion engine with a turbocharger that can improve the exhaust efficiency of the internal combustion engine having the turbocharger. is there.

  In order to achieve the above object, in the internal combustion engine with a turbocharger according to claim 1, the compressor disposed in the intake passage is rotated by rotating the turbine disposed in the exhaust passage of the internal combustion engine by exhaust gas. A turbocharger that supercharges intake air, a pipe expansion portion that is formed on the exhaust downstream side of the turbine of the exhaust passage and has a passage cross-sectional area that is larger than a passage cross-sectional area of the exhaust passage, and an inside of the pipe expansion portion And a rectifying plate that rectifies the vortex of the exhaust generated by the rotation of the turbine into a flow in the direction of exhaust transport.

In other words, by forming a pipe expansion part with a rectifying plate inside the exhaust downstream of the turbine, the pressure of the exhaust flow is reduced inside the pipe expansion part, and the vortex generated by the rotation of the turbine by the rectification plate is exhausted in the direction of exhaust transportation. Rectify to
In an internal combustion engine with a turbocharger according to a second aspect of the present invention, in the first aspect, the inside of the expanded pipe portion is characterized in that a central portion is hollow toward the exhaust transport direction.

That is, the central part inside the expanded pipe part is hollow in the exhaust transport direction, and the rectifying plate is provided only on the outer peripheral side of the expanded pipe part, so that the exhaust flow in the exhaust transport direction out of the exhaust flow flowing into the expanded pipe part. Passes through the hollow portion toward the exhaust downstream side, and the vortex generated by the rotation of the turbine is rectified in the exhaust transport direction by the rectifying plate toward the outer peripheral side of the expanded pipe portion by centrifugal force.
A turbocharged internal combustion engine according to a third aspect of the present invention is the turbocharger-equipped internal combustion engine according to the first or second aspect, wherein the rectifying plate is curved so that the exhaust upstream side is along the direction of the vortex flow of the exhaust, and the exhaust downstream side extends in the exhaust transport direction. It is characterized by being.

That is, the vortex flow that has flowed into the expanded pipe portion is guided and rectified by the rectifying plate in the exhaust transport direction.
According to a fourth aspect of the present invention, there is provided an internal combustion engine with a turbocharger according to any one of the first to third aspects, wherein the downstream end of the expanded pipe portion is connected to an exhaust pipe, and the exhaust downstream side of the expanded pipe section gradually reaches the passage cross-sectional area of the exhaust passage. It is characterized by being reduced to.

That is, the vortex flow that flows into the expanded pipe portion and expands to the outer peripheral side due to centrifugal force is rectified by the rectifying plate, converges again to the cross-sectional area of the exhaust passage downstream of the expanded pipe portion, and flows out to the downstream side of the exhaust.
An internal combustion engine with a turbocharger according to a fifth aspect of the present invention is the engine according to any one of the first to third aspects, further comprising exhaust purification means for purifying exhaust gas in the exhaust passage, wherein an exhaust upstream end of the exhaust purification means is an exhaust gas of the expanded pipe portion. It is connected to the downstream end.

  That is, the exhaust gas purification means is directly connected to the exhaust downstream end of the expanded pipe portion.

  According to the turbocharged internal combustion engine of the present invention using the above means, the vortex generated by the rotation of the turbine is rectified by the rectifying plate, so that the resistance due to the vortex is removed and the exhaust resistance is reduced. The pressure of the exhaust flow can be made uniform. Further, since the rectifying plate is provided in the expanded pipe portion, it is possible to easily rectify the vortex flow by the rectifying plate due to the pressure drop of the exhaust flow due to the expanded pipe.

Thereby, the exhaust efficiency of the internal combustion engine can be improved.
In addition, since the flow velocity distribution of the exhaust is made uniform by rectifying the vortex well and making the pressure in the exhaust pipe uniform, if the exhaust purification means is provided on the downstream side of the exhaust, the purification efficiency will be reduced. Therefore, the exhaust gas purification performance of the exhaust gas purification means can be sufficiently exhibited.
According to the turbocharged internal combustion engine of claim 2, the expanded pipe portion can rectify only the vortex without affecting the exhaust flow in the exhaust transport direction, so that the exhaust pressure is kept uniform while preventing the exhaust resistance from increasing. The exhaust resistance can be reduced more efficiently.

According to the turbocharged internal combustion engine of claim 3, the vortex flow that has flowed into the expanded pipe portion is formed such that the exhaust upstream side of the rectifying plate is curved along the vortex direction and the exhaust downstream side extends in the exhaust transport direction. Can be smoothly guided and reduced in the exhaust transport direction with less resistance.
According to the turbocharged internal combustion engine of the fourth aspect, the pressure in the exhaust pipe downstream of the expanded pipe can be made uniform by rectifying the vortex flowing in the expanded pipe and converging on the downstream side of the exhaust. .

According to the turbocharged internal combustion engine of the fifth aspect, the vortex generated by the rotation of the turbine is rectified in the expanded pipe portion, and the flow velocity distribution is made uniform and flows into the exhaust gas purification means. And the exhaust gas purification performance of the exhaust gas purification means can be sufficiently exerted.
Further, it is possible to reduce the size by directly connecting the expanded pipe portion to the exhaust gas purification means.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, the first embodiment will be described.
Referring to FIGS. 1 to 3, FIG. 1 shows a schematic configuration diagram of an internal combustion engine with a turbocharger according to a first embodiment of the present invention, and FIG. 2 is taken along line AA in FIG. A cross-sectional view is shown, and FIG. 3 shows a cross-sectional view along the line BB in FIG. Hereinafter, description will be made based on FIGS. 1 to 3.

  As shown in FIG. 1, an intake pipe 4 (intake passage) is connected to an intake side of an engine 1 (internal combustion engine) mounted on a vehicle via an intake manifold 2. The intake pipe 4 is provided with an air cleaner 6 at the intake upstream end, a turbocharger 20 for supercharging the intake air is provided on the intake downstream side, and further cools the intake air that has been supercharged and heated at the intake downstream side. An intercooler 8 is provided.

On the other hand, an exhaust pipe 12 (exhaust passage) is connected to the exhaust side of the engine 1 via an exhaust manifold 10. The exhaust pipe 12 is provided with a turbocharger 20 in the middle thereof, an expanded pipe portion 40 is formed in the vicinity of the exhaust downstream side, and an exhaust purification device 50 (exhaust gas) provided with a catalyst for purifying exhaust on the exhaust downstream side. Purification means) is provided.
As shown in FIG. 2, the turbocharger 20 is configured by connecting a compressor housing 22 and a turbine housing 24 by a center housing 26. A compressor impeller 28 (compressor) is provided in the compressor housing 22, and a turbine impeller 30 (turbine) is provided in the turbine housing 24. The compressor impeller 28 and the turbine impeller 30 are accommodated in the center housing 26. The rotating shaft 32 is connected so as to rotate synchronously.

  In the compressor housing 22 and the turbine housing 24, an intake outlet passage 22a and an exhaust inlet passage 24a are formed on the outer circumferences of the compressor impeller 28 and the turbine impeller 30, respectively. The compressor housing 22 and the turbine housing 24 are respectively formed with an intake inlet portion 22b connected to the intake pipe 4 and an exhaust outlet portion 24b connected to the exhaust pipe 12 in the axial direction of the rotary shaft 32. Has been.

And it is connected with the intake pipe 4 at the intake outlet passage 22a and the intake inlet portion 22b, and is connected to the exhaust pipe 12 at the exhaust inlet passage 24a and the exhaust outlet portion 24b.
Further, a pipe expansion portion 40 is formed in the vicinity of the exhaust downstream of the exhaust pipe 12 connected to the exhaust outlet portion 24b.
The pipe expansion portion 40 is formed to have a passage cross-sectional area (hereinafter referred to as an expanded pipe cross-sectional area) that is larger than a passage cross-sectional area of the exhaust pipe 12 (hereinafter referred to as an exhaust pipe cross-sectional area). Specifically, the exhaust upstream side of the pipe expansion portion 40 gradually increases from the exhaust pipe cross-sectional area at the exhaust upstream end, which is a connection portion with the exhaust pipe 12, to the pipe cross-sectional area toward the downstream side. On the other hand, the exhaust downstream side of the expanded pipe portion 40 is formed so as to gradually decrease from the expanded cross-sectional area to the exhaust pipe passage sectional area at the exhaust downstream end.

  Further, as shown in FIG. 3, the inside of the pipe expanding portion 40 includes a hollow area 40a on the extension of the exhaust pipe 12 and an outer peripheral area 40b on the outer peripheral side of the hollow area 40a. Are provided with four rectifying plates 42. The four rectifying plates 42 are perpendicular to the rotational direction R of the turbine impeller 30 and are arranged at equal intervals as seen in the cross section of FIG. Further, in the exhaust transport direction, the rectifying plate 42 is curved so that the exhaust upstream side follows the exhaust vortex generated by the rotation of the turbine impeller 30, and the exhaust downstream side extends in the exhaust transport direction. is doing.

Hereinafter, the operation of the turbocharged internal combustion engine according to the first embodiment of the present invention configured as described above will be described.
Exhaust gas discharged by driving the engine 1 flows from the exhaust manifold 10 through the exhaust pipe 12 into the exhaust inlet passage 24a of the turbine housing 24.
The exhaust flow passes through the exhaust inlet passage 24a, hits the turbine impeller 30, and rotates the turbine impeller 30. When the turbine impeller 30 rotates, the compressor impeller 28 rotates synchronously via the rotating shaft 32, and the intake air is supercharged by the rotation of the compressor impeller 28.

  On the other hand, the exhaust flow after rotating the turbine impeller 30 flows out from the exhaust outlet 24 b of the turbine housing 24 to the exhaust pipe 12. At this time, the exhaust flow toward the exhaust pipe 12 generates a vortex W1 that is a strong vortex component flow due to the rotation of the turbine impeller 30. By generating the vortex W1 in this manner, the exhaust resistance of the exhaust flow increases, and the vortex W1 is biased toward the outer peripheral side in the exhaust pipe 12 due to centrifugal force, and the pressure on the center side in the exhaust pipe 12 decreases.

Then, the exhaust flow flows into the expanded pipe portion 40.
The exhaust flow that has flowed into the expanded pipe portion 40 is reduced in exhaust pressure due to an increase in the cross-sectional area of the passage, and among the exhaust flow, the vortex W1 is expanded to the outer peripheral region 40b by centrifugal force, and the flow W2 in the transport direction is It flows through the hollow portion 40a on the extension of the exhaust pipe 12.
The vortex flow W1 flowing in the outer peripheral region 40b is rectified by the flow in the vortex direction being induced in the exhaust transport direction by the rectifying plate 42 having the above shape. At this time, since the rectifying plate 42 is curved on the exhaust upstream side along the vortex W1, the vortex W1 is smoothly guided by the rectifying plate 42 in the exhaust transport direction with little resistance.

  The exhaust flow W1 thus rectified converges to the central side of the expanded pipe portion 40 along the reduced shape of the expanded pipe portion 40 on the downstream side of the expanded pipe portion 40, and merges with the flow W2 in the transport direction. It flows out into the exhaust pipe 12 on the exhaust downstream side as W3. The exhaust flow W3 flowing out into the exhaust pipe 12 is rectified by the vortex flow W1 in the expanded portion 40, thereby reducing the exhaust resistance due to the vortex flow W1, making the pressure in the exhaust pipe 12 uniform, and the flow velocity distribution of the exhaust gas. Is also made uniform.

  Then, the rectified and uniform exhaust flow W3 that passes through the expanded pipe portion 40 flows into the exhaust purification device 50 through the exhaust pipe 12, and is purified by the catalyst provided in the exhaust purification device 50. Discharged into the atmosphere. At this time, the exhaust flow flowing into the exhaust purification device 50 is rectified in the pipe expansion section 40, and the flow velocity distribution is made uniform to circulate in the catalyst. The exhaust is purified.

  As described above, in the pipe expansion section 40, the vortex flow W1 generated by the rotation of the turbine impeller 30 can be rectified into the flow in the exhaust transport direction by the rectifying plate 42 in the outer peripheral region 40b. W2 can pass through the hollow region 40a having no particular resistance. That is, the expanded pipe portion 40 can rectify only the vortex flow W1 without affecting the exhaust flow W2 in the exhaust transport direction, thereby making it possible to equalize the exhaust pipe pressure while preventing an increase in exhaust resistance. Moreover, the said expanded pipe part 40 can reduce an exhaust pressure because the passage cross-sectional area is enlarged rather than the exhaust pipe 12, and can make it easy to rectify | straighten the said eddy current W1.

Thereby, in the first embodiment of the present invention, the exhaust efficiency can be improved and the purification efficiency of the catalyst can be improved in the turbocharged internal combustion engine.
Next, a second embodiment will be described.
Referring to FIGS. 4 to 6, FIG. 4 is a schematic configuration diagram of an internal combustion engine with a turbocharger according to a second embodiment of the present invention, and FIG. 5 is a cross-sectional view taken along line CC in FIG. 6 is a cross-sectional view taken along line DD in FIG. This will be described below with reference to FIGS. In addition, the same code | symbol is used about the same member as the said 1st Example, and description is abbreviate | omitted about the same function.

The second embodiment has a configuration in which an exhaust purification device 70 is directly connected to an expanded pipe portion 62 formed in the exhaust pipe 60 in the vicinity of the exhaust downstream of the turbocharger 20.
Specifically, in the exhaust pipe 60 connected to the exhaust outlet portion 24 b of the turbine housing 24, a pipe expansion portion 62 is formed in the vicinity of the exhaust downstream of the turbine housing 24.
The expanded pipe portion 62 is gradually expanded from the exhaust pipe cross-sectional area to the expanded cross-sectional area of the expanded pipe portion 62 on the exhaust upstream side.

On the other hand, the exhaust downstream side of the expanded pipe portion 62 is directly connected to the exhaust upstream end of the exhaust purification device 70, and the connection portion is further expanded from the expanded sectional area to the expanded section sectional area. It is formed to gradually expand until.
Further, as shown in FIG. 6, the inside of the expanded pipe portion 62 is composed of a hollow region 62a on the extension of the exhaust pipe 60 and an outer peripheral region 62b on the outer peripheral side of the hollow region 62a. Are provided with four rectifying plates 64. The four rectifying plates 64 are arranged in a cross shape extending from the outer peripheral side toward the center of the expanded tube portion 62 except for the hollow region 62a when viewed in the cross section of FIG. Further, the rectifying plate 64 has a linear shape extending in the exhaust transport direction in the exhaust transport direction.

A catalyst 72 is provided in the exhaust purification device 70.
The operation of the turbocharged internal combustion engine according to the second embodiment of the present invention thus configured will be described below.
As in the first embodiment, an exhaust flow in which a vortex W4 that is a strong vortex component flow generated by the rotation of the turbine impeller 30 is generated flows into the pipe expansion portion 62.

The exhaust flow that has flowed into the expanded pipe portion 62 has a reduced exhaust pressure due to an increase in the cross-sectional area of the passage, and among the exhaust flow, the vortex W4 expands to the outer peripheral region 62b in the expanded pipe portion 62 due to centrifugal force. The flow W5 to the left flows through the hollow portion 60a.
The vortex flow W4 flowing in the outer peripheral region 62b is rectified by the flow in the vortex direction being guided in the exhaust transport direction by the rectifying plate 64 having the above shape, and the flow velocity in the exhaust transport direction is accelerated.

The rectified exhaust flow W4 flows into the exhaust purification device 70 as it is.
In the exhaust purification device 70, since the catalyst 72 serves as a resistor, the rectified exhaust flow W4 and the exhaust flow W5 that has passed through the hollow region 62a in the expanded pipe portion 62 are uniformly dispersed on the front surface of the catalyst 72, while in the catalyst 72. It will be distributed to. Since the exhaust gas flowing through the catalyst 72 is made uniform in this way, the purification performance of the catalyst 72 is sufficiently exhibited, and the exhaust gas is reliably purified.

From the above, in addition to the effects of the first embodiment, a compact configuration can be achieved by directly connecting the expanded pipe portion 62 and the exhaust purification device 70, and a straight straightening rectifying plate 64 is used. However, it is possible to sufficiently rectify the vortex and make the exhaust gas uniform, and also in the second embodiment of the present invention, it is possible to improve the exhaust efficiency in the turbocharged internal combustion engine.
Although the description of the embodiment of the internal combustion engine with a turbocharger according to the present invention is finished above, the embodiment is not limited to the above embodiment.

For example, in the above-described embodiment, four rectifying plates are disposed. However, for example, one rectifying plate can be sufficiently rectified, and the number of rectifying plates may be any number. Further, the shape of the current plate is not limited to the shape in the above embodiment.
Moreover, in the said embodiment, although the pipe expansion part is provided in the exhaust downstream vicinity of a turbocharger, it is not restricted to this position, For example, you may provide in an exhaust downstream. However, in order to rectify the vortex generated by the rotation of the turbine impeller at an early stage, it is preferable to provide a pipe expansion part in the vicinity of the exhaust gas downstream of the turbocharger.

  Moreover, although the catalyst is provided in the exhaust purification apparatus in the above embodiment, a DPF or the like that is not limited to this may be provided.

1 is a schematic configuration diagram of an internal combustion engine with a turbocharger according to a first embodiment of the present invention. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which follows the BB line of FIG. It is a schematic block diagram of the internal combustion engine with a turbocharger which concerns on 2nd Example of this invention. It is sectional drawing which follows the CC line of FIG. It is sectional drawing which follows the DD line | wire of FIG.

Explanation of symbols

1 engine (internal combustion engine)
12, 60 Exhaust pipe (exhaust passage)
20 Turbocharger 24 Turbine housing 24b Exhaust outlet 30 Turbine impeller (turbine)
40, 62 Expanded pipe portion 42, 64 Current plate 50, 70 Exhaust gas purification device 72 Catalyst

Claims (5)

A turbocharger that supercharges intake air by rotating a compressor disposed in an intake passage by rotating a turbine disposed in an exhaust passage of the internal combustion engine by exhaust;
An expanded pipe portion formed on the exhaust downstream side of the turbine of the exhaust passage and having a passage cross-sectional area that is larger than a passage cross-sectional area of the exhaust passage;
An internal combustion engine with a turbocharger, comprising: a rectifying plate that is provided inside the expansion portion and rectifies an exhaust vortex generated by rotation of the turbine into a flow in an exhaust transport direction.   The turbocharged internal combustion engine according to claim 1, wherein a central portion of the inside of the expanded pipe portion is hollow toward the exhaust transport direction.   The turbocharger with turbocharger according to claim 1 or 2, wherein the rectifying plate is formed so that the exhaust upstream side is curved along the direction of the vortex flow of the exhaust, and the exhaust downstream side extends in the exhaust transport direction. Internal combustion engine.   The turbocharger according to any one of claims 1 to 3, wherein a downstream end of the expanded pipe portion is connected to an exhaust pipe, and an exhaust downstream side of the expanded pipe portion is gradually reduced to a passage cross-sectional area of the exhaust passage. Internal combustion engine. The exhaust passage further includes exhaust purification means for purifying exhaust,
The turbocharged internal combustion engine according to any one of claims 1 to 3, wherein an exhaust upstream end of the exhaust purification means is connected to an exhaust downstream end of the expansion portion.

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