WO2017221841A1

WO2017221841A1 - Egr gas cooler and engine system

Info

Publication number: WO2017221841A1
Application number: PCT/JP2017/022378
Authority: WO
Inventors: 隆道細野; 正憲東田; 雅英餝; 英和岩▲崎▼; 中島　隆博; 和巳庄司; 和彦高山
Original assignee: 川崎重工業株式会社; 川崎エンジニアリング株式会社
Priority date: 2016-06-21
Filing date: 2017-06-16
Publication date: 2017-12-28
Also published as: JP6749150B2; CN109312694A; KR20190012257A; KR102073795B1; CN109312694B; JP2017227153A

Abstract

An EGR gas cooler according to one aspect of the present invention is provided with: a case that has a pair of opposing end surfaces and a pair of opposing side surfaces, and that, by means of the pair of end surfaces and pair of side surfaces, sections off a flow channel through which an EGR gas flows vertically downward; a fin group comprising a plurality of fins positioned in the flow channel and aligned parallel to the pair of end surfaces; a tube which passes through the fins of the fin group and inside of which a refrigerant flows; and barriers that are disposed along the side surfaces and that extend horizontally.

Description

EGR gas cooler and engine system

The present invention relates to an EGR gas cooler and an engine system.

Exhaust gas recirculation (EGR) technology that recirculates exhaust gas to the engine has a large NOx emission reduction effect and is widely applied to low environmental load engines. This EGR is also effective for large marine diesel engines. However, if the temperature of the exhaust gas (EGR gas) to be recirculated is high, the supply ratio of the scavenging gas is reduced and the fuel consumption is deteriorated. Therefore, an EGR gas cooler for cooling the EGR gas is required.

Also, since large marine diesel engines use heavy oil as fuel, the exhaust gas contains a large amount of sulfur oxide (SOx) and particulate matter (PM). Therefore, a wet cleaning device (scrubber) that cleans EGR gas with a cleaning liquid is also required (see Patent Document 1). In addition, when there are few SOx and PM contained in EGR gas, a scrubber may be comprised integrally with an EGR gas cooler (refer patent document 2). Then, in the EGR gas cooler, condensed water generated by cooling the EGR gas or a cleaning liquid for cleaning the EGR gas (hereinafter referred to as “internal fluid”) flows.

JP 2011-157959 A International Publication No. 2014/148048

Here, it has been found that when the EGR gas cooler is of a fin tube type, the flow of the internal liquid in the EGR gas cooler is biased. If the flow of the internal liquid is biased, the temperature of the internal liquid at the outlet of the EGR gas cooler increases, so that the temperature of the EGR gas in contact with the internal liquid also rises, and the EGR gas may not be sufficiently cooled. is there.

The present invention has been made in view of the circumstances as described above, and an object thereof is to suppress the uneven flow of the internal liquid in the fin tube type EGR gas cooler.

An EGR gas cooler according to an aspect of the present invention has a pair of opposing end surfaces and a pair of opposing side surfaces, and defines a flow path through which EGR gas flows downward in the vertical direction by the pair of end surfaces and the pair of side surfaces. A case, a fin group consisting of a plurality of fins positioned in the flow path and arranged in parallel to the pair of end faces, a tube that passes through the fin group and into which refrigerant flows, and along the side surface And a horizontally extending barrier.

When the internal liquid flowing through the fin tube type EGR gas cooler passes between the fins, the surface tension works and slowly flows down. Further, the flow direction changes every time the tube is contacted. For this reason, the internal liquid concentrates on the side surface without the fin tube, and actively flows downward along the side surface in the vertical direction. As a result, the flow of the internal liquid flow is biased.

On the other hand, in the EGR gas cooler described above, since the internal liquid flowing along the side surface can be blocked by the barrier, the internal liquid flowing can be suppressed from flowing along the side surface, and thus the flow of the internal liquid flow. Can be suppressed.

In the EGR gas cooler, the barrier may be disposed at least between a vertical upper end and a vertical lower end of the fin group.

According to this configuration, the flow direction of the internal liquid flow that has been guided by the fins and reached the side surface can be changed again by the barrier, and the internal flow liquid can be returned to the center side of the flow path. Therefore, it is possible to efficiently suppress the uneven flow of the internal liquid flow.

In the EGR gas cooler described above, the fin group includes a first-stage fin group including a plurality of fins arranged at the same vertical position and a plurality of fins arranged at the same vertical position. A second-stage fin group that is vertically separated from the fin group, and the barrier may be disposed between the first-stage fin group and the second-stage fin group.

According to this configuration, the barrier can be disposed between the vertical upper end and the vertical lower end of the fin group without processing the fin into a complicated shape.

In the above EGR gas cooler, the barrier may be positioned above the vertical upper end of the fin group in the vertical direction.

According to this configuration, the flow along the side surface of the internal fluid can be suppressed upstream of the fin group. Therefore, it is possible to efficiently suppress the uneven flow of the internal liquid flow.

In the above EGR gas cooler, the barrier may have an inclined surface that is inclined downward in the vertical direction from the side surface toward the center of the flow path.

According to this configuration, it is possible to guide the internal liquid flowing along the side surface of the inclined surface toward the center of the flow path. Therefore, the direction of the flow of the internal liquid can be greatly changed, and the uneven flow of the internal liquid can be suppressed.

In the EGR gas cooler described above, in the opposing direction of the pair of side surfaces, the position of the flow path center side end portion of the barrier disposed along the side surfaces is the same as the position of the central axis of the tube adjacent to the side surfaces or It may be closer to the center of the flow path than the position of the central axis.

According to this configuration, the internal liquid liquid guided by the barrier goes to the center of the flow path through the tube close to the side surface. Therefore, it is possible to further suppress the uneven flow of the internal liquid flow.

The EGR gas cooler may further include a cleaning nozzle that is positioned vertically above the fin group and that injects a cleaning liquid downward in the vertical direction.

As described above, even when the EGR gas cooler includes the cleaning nozzle that injects the cleaning liquid, by providing the barrier as described above, it is possible to suppress the cleaning liquid (internal liquid flow) from flowing along the side surface. .

An engine system according to an aspect of the present invention includes the EGR gas cooler described above.

An engine system according to another aspect of the present invention includes the above-described EGR gas cooler, and a scrubber that is located upstream of the EGR gas cooler and that cleans the EGR gas using a cleaning liquid.

Thus, even when the engine system includes a scrubber positioned upstream of the EGR gas cooler, the condensed water (internal fluid) generated by cooling the EGR gas is provided on the side surface by providing the barrier as described above. It can suppress flowing along.

According to the above EGR gas cooler, it is possible to suppress the bias of the internal liquid flow.

FIG. 1 is a schematic configuration diagram of an engine system according to the first embodiment. FIG. 2 is a cross-sectional view of the EGR gas cooler shown in FIG. 3 is a cross-sectional view taken along arrow III-III in FIG. FIG. 4 is a diagram illustrating the flow of the cleaning liquid in the comparative example. FIG. 5 is a diagram illustrating the flow of the cleaning liquid in the first embodiment. FIG. 6 is a view showing a modification of the first embodiment. FIG. 7 is a schematic configuration diagram of an engine system according to the second embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Below, the same code | symbol is attached | subjected to the element which is the same or it corresponds through all the drawings, and the overlapping description is abbreviate | omitted.

(First embodiment)
<Engine system>
First, a schematic configuration of the engine system 100 according to the first embodiment will be described. FIG. 1 is a schematic configuration diagram of an engine system 100 according to the first embodiment. In FIG. 1, the thick dashed line indicates the flow of exhaust gas and EGR gas, and the thick solid line indicates the flow of fresh air and scavenging gas.

The engine system 100 according to the present embodiment is a marine engine system, which is an engine main body 10 that is a two-stroke diesel engine, a scavenging flow passage 20 that supplies scavenging gas to the engine main body 10, and exhausted from the engine main body 10. An exhaust passage 30 that discharges the exhaust gas to the outside, a supercharger 40 that is driven by the energy of the exhaust gas and boosts fresh air, and an EGR that extracts the exhaust gas from the exhaust passage 30 and supplies it to the scavenging passage 20 Unit 50.

The scavenging flow path 20 is provided with an air cooler 21 that cools fresh air. The fresh air cooled by the air cooler 21 merges with the EGR gas supplied from the EGR unit 50 at the merge point 22. The scavenging gas is generated by the combination of the fresh air and the EGR gas, and the generated scavenging gas is supplied to the engine body 10 via the water mist catcher 23. Note that the water mist catcher 23 collects condensed water or the like generated when fresh air is cooled by the air cooler 21.

The EGR unit 50 includes an EGR flow path 51 that connects the scavenging flow path 20 and the exhaust flow path 30, an EGR gas cooler 53 that is provided in the EGR flow path 51 and cools EGR gas, and an EGR gas cooler 53 that is provided in the EGR flow path 51. It has an EGR water mist catcher 54 that collects the condensed water and washing water that is discharged, and an EGR blower 55 that is provided in the EGR flow path 51 and boosts the exhaust gas and adjusts the flow rate of the EGR gas.

<EGR gas cooler>
Next, a detailed configuration of the EGR gas cooler 53 will be described. 2 is a cross-sectional view of the EGR gas cooler 53, and FIG. 3 is a cross-sectional view taken along arrows III-III in FIG. In FIG. 2, the upper side of the paper is the upper side in the vertical direction, and the lower side of the paper is the lower side in the vertical direction. As shown in FIGS. 2 and 3, the EGR gas cooler 53 of this embodiment is a so-called fin tube type cooler, and includes a case 61, a fin group 62, a tube 63, a barrier 64, and a cleaning nozzle 65. ,have.

As shown in FIG. 3, the case 61 divides the rectangular outer frame member 70 in the horizontal sectional view, the first partition member 71 that partitions the inner space of the outer frame member 70, and the inner space of the outer frame member 70. A second partition member 72. The case 61 has a pair of opposed end surfaces 73 and a pair of opposed side surfaces 74. One of the end surfaces 73 is an inner surface of the first partition member 71, and the other is an inner surface of the second partition member 72. Further, the side surface 74 is a portion located between the first partition member 71 and the second partition member 72 in the inner surface of the outer frame member 70.

The pair of end surfaces 73 and the pair of side surfaces 74 define a rectangular channel 75 in a horizontal sectional view. The EGR gas flows through the channel 75 downward in the vertical direction (downward in the drawing of FIG. 2). A refrigerant supply chamber 76 is defined by the outer surface of the first partition member 71 and the inner surface of the outer frame member 70, and a refrigerant discharge chamber 77 is defined by the outer surface of the second partition member 72 and the inner surface of the outer frame member 70. Yes.

The fin group 62 is located in the flow path 75 and includes a plurality of fins 80 arranged in parallel to the end face 73. As shown in FIG. 2, the fin group 62 includes a first-stage fin group 81, a second-stage fin group 82, and a third-stage fin group 83 in order from the upper side in the vertical direction. The first stage fin group 81 and the second stage fin group 82 are separated in the vertical direction, and the second stage fin group 82 and the third stage fin group 83 are separated in the vertical direction.

The first-stage fin group 81 is composed of a plurality of fins 80 arranged at the same vertical position. Similarly, the second-stage fin group 82 includes a plurality of fins 80 arranged at the same vertical position, and the third-stage fin group 83 includes a plurality of fins arranged at the same vertical position. 80.

As shown in FIG. 3, the tube 63 passes through the plurality of fins 80 constituting the fin group 62 and extends from one end surface 73 to the other end surface 73. The tube 63 has one end opened to the refrigerant supply chamber 76 and the other end opened to the refrigerant discharge chamber 77. The refrigerant supply room 76 and the refrigerant discharge room 77 are filled with a refrigerant for cooling the EGR gas. The pressure in the refrigerant supply chamber 76 is higher than the pressure in the refrigerant discharge chamber 77. Therefore, the refrigerant flows from the refrigerant supply chamber 76 through the inside of the tube 63 toward the refrigerant discharge chamber 77.

The barrier 64 extends in the horizontal direction from one end surface 73 to the other end surface 73 and is disposed along both side surfaces 74. The barrier 64 is located above the upper end in the vertical direction of the fin group 62 and below the lower end in the vertical direction of the fin group 62. Further, the barrier 64 is located between the upper end in the vertical direction and the lower end in the vertical direction of the fin group 62. Specifically, the barrier 64 is disposed between the first-stage fin group 81 and the second-stage fin group 82, and is disposed between the second-stage fin group 82 and the third-stage fin group 83. .

The barrier 64 of the present embodiment is a rod-shaped member having a rectangular cross section, and is fixed to the side surface 74. However, the barrier 64 may have a shape other than a rectangular cross section, as will be described in a later-described modification. Further, the barrier 64 may be formed in a straight line shape, or may be formed in a shape other than a straight line shape such as a wave shape. The barrier 64 may be divided at a plurality of locations. Further, the barrier 64 may be fixed to the fin group 62 instead of being fixed to the side surface 74.

Further, as shown in FIG. 2, in the opposing direction of both side surfaces 74 (left and right direction in FIG. 2), the position of the end of the barrier 64 on the channel center side is closest to the side surface 74 to which the barrier 64 is fixed. It is the same as the position of the central axis of the tube 63 to be performed. However, the flow path center side edge part of the barrier 64 may be located near the center of the flow path rather than the central axis of the tube 63 closest to the side face 74 to which the barrier 64 is fixed.

The cleaning nozzle 65 is positioned above the fin group 62 in the vertical direction, and sprays the cleaning liquid 101 downward in the vertical direction. The cleaning nozzle 65 is attached to a cleaning pipe 66 that extends from one side surface 74 to the other side surface 74. The cleaning liquid 101 is supplied from a cleaning tank (not shown) to the cleaning pipe 66 and is sprayed from the cleaning pipe 66 through the cleaning nozzle 65. A plurality of cleaning pipes 66 are arranged between both end faces 73.

<Flow of cleaning liquid>
Next, the flow of the cleaning liquid 101 in the EGR gas cooler 53 will be described. First, the flow of the cleaning liquid 101 in the EGR gas cooler 53 of the comparative example will be described. FIG. 4 is a diagram illustrating the flow of the cleaning liquid 101 in the comparative example. The EGR gas cooler 53 of the comparative example does not have the barrier 64. Further, in the EGR gas cooler 53 of the comparative example, the fin group 62 is not divided in the vertical direction. That is, the fin group 62 of the comparative example does not have the first-stage fin group 81, the second-stage fin group 82, and the third-stage fin group 83. However, except for the above points, the EGR gas cooler 53 of the comparative example has the same configuration as the EGR gas cooler 53 of the present embodiment.

As described above, the cleaning nozzle 65 provided in the EGR gas cooler 53 injects the cleaning liquid 101 downward in the vertical direction. The sprayed cleaning liquid 101 changes the flow direction in a plane perpendicular to the tube 63 by contacting the tube 63. Here, if the EGR gas cooler 53 does not have the fins 80, the cleaning liquid 101 in contact with the tube 63 flows along the outer peripheral surface of the tube 63, and then falls downward in the vertical direction by gravity.

However, in the case of the EGR gas cooler 53 having the fins 80, the surface tension acts on the cleaning liquid 101 passing between the fins 80, and flows slowly between the fins 80 while the flow direction is changed by the tubes 63. On the other hand, the cleaning liquid 101 that is guided to the side surface 74 and flows along the side surface 74 hardly comes into contact with the fins 80 and does not come into contact with the tubes 63, so that the velocity of flowing downward in the vertical direction is high. As a result, the cleaning liquid 101 in the vicinity of the side surface 74 is easily drawn into the side surface, and the cleaning liquid 101 is more easily collected on the side surface 74. As a result, as shown in FIG. 4, a large amount of the cleaning liquid 101 flows along the side surface 7, and the flow of the cleaning liquid 101 is biased.

Subsequently, the flow of the cleaning liquid 101 in the EGR gas cooler 53 of this embodiment will be described. FIG. 5 is a view showing the flow of the cleaning liquid 101 in the EGR gas cooler 53 of the present embodiment. Also in the EGR gas cooler 53 of the present embodiment, the cleaning liquid 101 ejected downward from the cleaning nozzle 65 in the vertical direction changes in the flow direction by coming into contact with the tube 63 and easily collects on the side surface 74 having a small fluid resistance.

However, the EGR gas cooler 53 of this embodiment includes a barrier 64 provided along the side surface 74. Therefore, the cleaning liquid 101 that flows downward in the vertical direction along the side surface 74 is blocked by the barrier 64. Thereby, in this embodiment, it can suppress that the washing | cleaning liquid 101 flows along the side surface 74, and can suppress the bias | inclination of the flow of the washing | cleaning liquid 101. FIG. As a result, it is possible to suppress the EGR gas from being heated by the cleaning liquid 101 in the vicinity of the outlet of the EGR gas cooler 53, and thus the EGR gas can be sufficiently cooled.

Further, as described above, in the present embodiment, in the facing direction of the both side surfaces 74, the position of the flow path center side end portion of the barrier 64 is the central axis of the tube 63 closest to the side surface 74 to which the barrier 64 is fixed. The position is the same. Therefore, the cleaning liquid 101 blocked by the barrier 64 is guided toward the center of the flow path 75 beyond the tube 63 closest to the side surface 74. As a result, the uneven flow of the cleaning liquid 101 can be further suppressed.

Of the barriers 64 provided at a plurality of locations, the barrier 64 positioned above the fin group 62 in the vertical direction blocks the cleaning liquid 101 sprayed directly from the cleaning nozzle 65 onto the side surface 74 before reaching the fin group 62. be able to. Further, the barrier 64 positioned below the fin group 62 in the vertical direction can suppress the flow rate of the cleaning liquid 101 toward the vertical direction. Thereby, it can suppress that the washing | cleaning liquid 101 of the side surface 74 vicinity is drawn in to the side surface 74 side.

In addition, in order to install each barrier 64, a notch may be formed in a predetermined portion of the fin 80, and the barrier 64 may be inserted into the notch. However, as in the present embodiment, the fin group 62 is separated in the vertical direction, and the vertical direction of the separated fin groups (first-stage fin group 81, second-stage fin group 82, third-stage fin group 83) is vertically If the barrier 64 is provided on the fin 80, it is not necessary to process the fin 80 into a complicated shape.

In the above description, the case where the cross-sectional shape of the barrier 64 is rectangular has been described, but the cross-sectional shape of the barrier 64 is not limited thereto. For example, as shown in FIG. 6, the cross-sectional shape of the barrier 64 may be triangular, and may have an inclined surface 67 that is inclined downward in the vertical direction from the side surface 74 toward the center of the flow path 75. According to this configuration, the flow direction of the cleaning liquid 101 flowing along the side surface 74 can be changed to the direction toward the center of the flow path 75 by the inclined surface 67. For this reason, the uneven flow of the cleaning liquid 101 can be further suppressed.

The inclined surface 67 may have a shape that is curved in a cross-sectional view. Even in this case, the flow direction of the cleaning liquid 101 can be changed to a direction toward the center of the flow path 75. Further, the barrier 64 may be formed in a plate shape and may be installed so as to be inclined downward in the vertical direction from the side surface 74 toward the center of the flow path 75. Even in this case, the barrier 64 has the inclined surface 67 inclined downward in the vertical direction from the side surface 74 toward the center of the flow path 75.

In the above description, the case where the tube 63 is linear and extends from one end surface 73 to the other end surface 73 has been described, but the shape of the tube 63 is not limited thereto. For example, the tube 63 may have a shape in which S-shapes are connected, and may be formed so as to be folded back multiple times in the flow path 75, and one tube 63 may penetrate a plurality of locations of the fin group 62.

(Second Embodiment)
Next, an engine system 200 according to the second embodiment will be described. FIG. 7 is a schematic configuration diagram of an engine system 200 according to the second embodiment. As shown in FIG. 7, the engine system 200 according to the present embodiment has a scrubber 52 upstream of the EGR gas cooler 53. In the scrubber 52, the EGR gas is cleaned using the cleaning liquid 101. That is, the EGR gas that has been cleaned is supplied to the EGR gas cooler 53 of the present embodiment.

In the present embodiment, the EGR gas cooler 53 does not have the cleaning nozzle 65 for injecting the cleaning liquid 101, and does not perform cleaning of the EGR gas. However, with respect to other points, the EGR gas cooler 53 of the present embodiment and the EGR gas cooler 53 of the first embodiment have the same configuration. As described above, in the present embodiment, the EGR gas containing a large amount of moisture by the scrubber 52 is cooled by the EGR gas cooler 53, so that a large amount of condensed water is generated in the EGR gas cooler 53.

This condensed water flows in the EGR gas cooler 53 in the same manner as the cleaning liquid 101 of the first embodiment. And since the EGR gas cooler 53 of this embodiment also has the barrier 64 mentioned above, it can suppress that the condensed water which flows along the side surface 74 is dammed up by the barrier 64, and that the flow of condensed water arises unevenly. it can. As a result, the EGR gas is prevented from being heated by the condensed water in the vicinity of the outlet of the EGR gas cooler 53, and the EGR gas can be sufficiently cooled.

52 Scrubber 53 EGR gas cooler 61 Case 62 Fin group 63 Tube 64 Barrier 65 Cleaning nozzle 66 Cleaning pipe 67 Inclined surface 73 End surface 74 Side surface 75 Channel 80 Fin 81 First stage fin group 82 Second stage fin group 83 Third

stage fin group

100, 200 Engine system 101 Cleaning fluid (internal fluid)

Claims

A case having a pair of opposed end surfaces and a pair of opposed side surfaces, and defining a flow path in which EGR gas flows downward in the vertical direction by the pair of end surfaces and the pair of side surfaces;
A fin group consisting of a plurality of fins positioned in the flow path and arranged in parallel to the pair of end faces;
A tube that passes through the fins of the fin group and in which a refrigerant flows;
An EGR gas cooler comprising: a barrier disposed along the side surface and extending in a horizontal direction.
The EGR gas cooler according to claim 1, wherein the barrier is disposed at least between a vertical upper end and a vertical lower end of the fin group.
The fin group includes a first-stage fin group including a plurality of fins arranged at the same vertical position and a plurality of fins arranged at the same vertical position, and is perpendicular to the first-stage fin group. A second stage fin group spaced apart in the direction,
The EGR gas cooler according to claim 2, wherein the barrier is disposed between the first-stage fin group and the second-stage fin group.
The EGR gas cooler according to any one of claims 1 to 3, wherein the barrier is positioned vertically above a vertical upper end of the fin group.
The EGR gas cooler according to any one of claims 1 to 4, wherein the barrier has an inclined surface that is inclined downward in the vertical direction from the side surface toward the center of the flow path.
In the facing direction of the pair of side surfaces, the position of the flow channel central side end portion of the barrier disposed along the side surfaces is the same as the position of the central axis of the tube adjacent to the side surfaces or the position of the central axis. The EGR gas cooler according to claim 1, which is also close to the center of the flow path.
The EGR gas cooler according to any one of claims 1 to 6, further comprising a cleaning nozzle that is positioned above the fin group in the vertical direction and injects a cleaning liquid downward in the vertical direction.
An engine system comprising the EGR gas cooler according to claim 7.
An engine system comprising: the EGR gas cooler according to claim 1; and a scrubber located upstream of the EGR gas cooler and cleaning the EGR gas using a cleaning liquid.