KR20190012257A - EGR gas cooler and engine system - Google Patents

Abstract

An EGR gas cooler according to an embodiment of the present invention has a pair of side faces facing a pair of opposite end faces, and the EGR gas flows downward in the vertical direction by the pair of end faces and the pair of side faces A case having a case for partitioning the flow path, a pin group which is located in the flow path and which is composed of a plurality of fins arranged in parallel to a pair of end faces, a tube through which the fins of the pin group pass and in which the refrigerant flows, And has an extended barrier.

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 the exhaust gas to the engine has a large effect of reducing NOx emissions and is widely applied to low environmental load engines. These EGRs are also effective in large marine diesel engines. However, if the temperature of the exhaust gas (EGR gas) to be recirculated is high, the ratio of supply of the scavenging gas is lowered and the fuel efficiency is deteriorated. Therefore, an EGR gas cooler for cooling the EGR gas is required.

In addition, heavy-duty marine diesel engines contain heavy sulfur oxides (SOx) and particulate matter (PM) in the exhaust gas because they use heavy oil as fuel. Therefore, a wet scrubber (scrubber) for scrubbing EGR gas with a scrubbing liquid is also required (see Patent Document 1). Here, when the SOx and PM contained in the EGR gas are small, the scrubber may be integrally formed with the EGR gas cooler (see Patent Document 2). According to this, in the EGR gas cooler, a cleaning liquid (hereinafter referred to as " internal fluid ") for cleaning the condensed water or EGR gas generated by the cooling of the EGR gas flows.

Japanese Patent Application Laid-Open Specification No. 2011-157959 International Publication No. 2014/148048

It has been found that when the EGR gas cooler is of the fin tube type, there is a bias in the flow of the internal fluid in the EGR gas cooler. When a deflection occurs in the flow of the internal fluid, the temperature of the internal fluid at the outlet of the EGR gas cooler increases, and the temperature of the EGR gas in contact with the internal fluid also rises, possibly preventing the EGR gas from cooling sufficiently .

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress the deflection of the flow of the internal fluid in the fin tube type EGR gas cooler.

An EGR gas cooler according to an embodiment of the present invention includes a pair of side surfaces opposed to a pair of end surfaces facing each other, and the EGR gas is supplied vertically by the pair of end surfaces and the pair of side surfaces. A pin group formed in the flow path and composed of a plurality of fins arranged in parallel to the pair of end faces; a tube through which the fins of the pin group pass and in which the coolant flows; And a barrier disposed along the side surface and extending in the horizontal direction.

The internal fluid flowing through the fin-tube EGR gas cooler drops slowly due to surface tension when passing between the pins. Further, the flow direction changes every time the tube is brought into contact with the tube. Therefore, the internal fluid is concentrated on the side where the fin tube is not present, and flows positively toward the downward direction in the vertical direction. As a result, there is a bias in the flow of the internal fluid.

On the other hand, since the EGR gas cooler can block the inner fluid flowing along the side by the barrier, it is possible to suppress the inner fluid from flowing along the side surface, thereby suppressing the deflection of the flow of the inner fluid can do.

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

According to this configuration, the flow direction of the internal fluid that has been guided by the fins and reaches the side surface can be changed again by the barrier, and the internal fluid can be returned to the central point of the flow path. Therefore, the deflection of the flow of the internal fluid can be effectively suppressed.

In the EGR gas cooler, the pin group includes a first short pin group composed of a plurality of pins arranged at the same vertical position, and a plurality of pins arranged at the same vertical position, Group, and the barrier may be disposed between the first-stage pin group and the second-stage pin group.

According to this configuration, it is possible to arrange the barrier between the upper end in the vertical direction and the lower end in the vertical direction of the pin group without processing the pin into a complicated shape.

In the EGR gas cooler, the barrier is located vertically above the vertically upper end of the pin group.

With this configuration, the flow along the side surface of the internal fluid can be suppressed upstream of the pin group. Therefore, the deflection of the flow of the internal fluid can be effectively suppressed.

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

According to this configuration, the inner fluid flowing along the side surface of the inclined surface can be guided to the center of the flow path. Therefore, the direction of the flow of the internal fluid can be largely changed, and the deflection of the flow of the internal fluid can be suppressed.

In the EGR gas cooler, the position of the center side end portion of the barrier disposed along the side surface in the opposite direction of the pair of side surfaces is the same as the position of the center axis of the tube close to the side surface, It may be closer to the center of the flow path.

With this arrangement, the inner fluid guided by the barrier is directed to the center of the flow path beyond the tube near the side. Therefore, the deflection of the flow of the internal fluid can be further suppressed.

The EGR gas cooler may further include a cleaning nozzle located above the pin group in the vertical direction and injecting the cleaning liquid downward in the vertical direction.

Accordingly, even when the EGR gas cooler is provided with the cleaning nozzle for jetting the cleaning liquid, it is possible to prevent the cleaning liquid (the inner fluid) from flowing along the side surface by providing such a barrier.

The engine system according to an embodiment of the present invention includes the EGR gas cooler.

An engine system according to another embodiment of the present invention includes a scrubber positioned upstream of the EGR gas cooler and the corresponding EGR gas cooler and cleaning the EGR gas using a cleaning liquid.

Therefore, even when the engine system is provided with a scrubber positioned upstream of the EGR gas cooler, it is possible to prevent the condensed water (the internal fluid) generated by cooling the EGR gas from flowing along the side surface by providing such a barrier.

According to the EGR gas cooler, the deflection of the internal fluid can be suppressed.

1 is a schematic configuration diagram of an engine system according to the first embodiment.
2 is a sectional view of the EGR gas cooler shown in Fig.
3 is a sectional view taken along the line III-III in Fig.
4 is a view showing the flow of the cleaning liquid in the comparative example.
5 is a view showing the flow of the cleaning liquid in the first embodiment.
6 is a view showing a modification of the first embodiment.
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. In the following description, the same or corresponding elements are denoted by the same reference numerals throughout the drawings, and redundant description will be omitted.

(Embodiment 1)

<Engine system>

First, a schematic configuration of the engine system 100 according to the first embodiment will be described. 1 is a schematic configuration diagram of an engine system 100 according to a first embodiment. In FIG. 1, the thick dotted lines indicate the flows of the exhaust gas and the EGR gas, and the thick solid lines indicate the flows of fresh gas and scavenging gas.

The engine system 100 according to the present embodiment is a marine engine system and includes an engine main body 10 as a two stroke diesel engine, a scavenging flow passage 20 for supplying scavenging gas to the engine main body 10, An exhaust gas passage 30 for exhausting the exhaust gas discharged from the engine 10 to the outside, a supercharger 40 for boosting the output of the engine by the energy of the exhaust gas, And an EGR unit (50) for supplying the EGR gas (20).

The scavenging passage 20 is provided with an air cooler 21 for cooling the fresh air. The cooler cooled in the air cooler 21 joins the EGR gas supplied from the EGR unit 50 at the junction point 22. The combined gas and EGR gas generates a desired gas, and the generated desired gas is supplied to the engine body 10 through a water mist catcher 23. Here, in the water mist catcher 23, condensed water generated when the fresh air is cooled by the air cooler 21 is collected.

The EGR unit 50 includes an EGR passage 51 connecting the blanket passage 20 and the exhaust passage 30, an EGR gas cooler 53 installed in the EGR passage 51 for cooling the EGR gas, An EGR water mist catcher 54 provided in the EGR passage 51 for collecting condensed water and cleansing water discharged from the EGR gas cooler 53 and an EGR water mist catcher 54 provided in the EGR passage 51 for increasing the exhaust gas flow rate, And an EGR blower 55 for regulating the EGR amount.

<EGR gas cooler>

Next, the detailed configuration of the EGR gas cooler 53 will be described. Fig. 2 is a sectional view of the EGR gas cooler 53, and Fig. 3 is a sectional view taken along the line III-III in Fig. In Fig. 2, the upper side of the paper surface is the upper side in the vertical direction, and the lower side of the paper is the lower side in the vertical direction. 2 and 3, the EGR gas cooler 53 of the present embodiment is a so-called fin tube type cooler and includes a case 61, a pin group 62, a tube 63, a barrier 64 ), And a cleaning nozzle 65. The cleaning nozzle

3, the case 61 includes a frame member 70, which is rectangular when viewed in a horizontal section, a first partition member 71 that divides the inner space of the frame member 70, And a second partitioning member (72) for dividing the inner space of the second partition member (70). Further, the case 61 has a pair of end faces 73 facing each other and a pair of side faces 74 facing each other. One of the end faces 73 is the inner face of the first partitioning member 71 and the other is the inner face of the second partitioning member 72. The side surface 74 is a portion of the inner surface of the frame member 70 located between the first partitioning member 71 and the second partitioning member 72.

The rectangular passage 75 is defined by the pair of end surfaces 73 and the pair of side surfaces 74 when seen in a horizontal section. The EGR gas flows downward in the vertical direction (downward in FIG. 2) of the flow path 75. The refrigerant supply chamber 76 is partitioned by the outer surface of the first partition member 71 and the inner surface of the frame member 70 and the outer surface of the second partition member 72 and the inner surface of the frame member 70 The refrigerant discharge chamber 77 is partitioned.

The pin group 62 is located in the flow path 75 and is constituted by a plurality of pins 80 arranged in parallel to the end surface 73. 2, the pin group 62 includes a first-stage pin group 81, a second-stage pin group 82, a third-stage pin group 83 and a third-stage group 83 in this order from the upper side in the vertical direction, Lt; / RTI &gt; The first stage pin group 81 and the second stage pin group 82 are vertically spaced apart and the second stage pin group 82 and third stage stage pin group 83 are vertically spaced apart .

The first stage pin group 81 is composed of a plurality of pins 80 arranged at the same vertical position with respect to each other. Similarly, the second stage pin group 82 is composed of a plurality of pins 80 arranged at the same vertical position with respect to each other, and the third stage pin group 83 includes a plurality of pins (80).

The tube 63 penetrates through the plurality of pins 80 constituting the pin group 62 and extends from one end face 73 to the other end face 73 as shown in Fig. One end of the tube 63 is opened in the refrigerant supply chamber 76 and the other end is opened in the refrigerant discharge chamber 77. The coolant supply chamber 76 and the coolant discharge chamber 77 are filled with a coolant for cooling the EGR gas. The pressure of the refrigerant supply chamber 76 is higher than the pressure of the refrigerant discharge chamber 77. Therefore, the refrigerant flows from the refrigerant supply chamber 76 through the inside of the tube 63 to the refrigerant discharge chamber 77. [

The barrier 64 extends horizontally from one end face 73 to the other end face 73 and is disposed along both side faces 74. The barrier 64 is located above the upper end in the vertical direction of the pin group 62 and below the lower end in the vertical direction of the pin group 62. Furthermore, the barrier 64 is also located between the upper vertical direction and the lower vertical direction of the pin group 62. Specifically, the barrier 64 is disposed between the first-stage pin group 81 and the second-stage pin group 82, and between the second-stage pin group 82 and the third-stage pin group 83 Respectively.

In this embodiment, the barrier 64 is a rod-shaped member having a square cross section and is fixed to the side surface 74. [ However, the barrier 64 may have a shape other than a quadrangle in cross section, as described in a modified example to be described later. Further, the barrier 64 may be formed in a linear shape, or may be formed in a shape other than a linear shape such as a wave shape. Further, the barrier 64 may be divided at a plurality of locations. Further, the barrier 64 may be fixed to the pin group 62 instead of being fixed to the side surface 74.

2, the position of the flow path center side end portion of the barrier 64 in the opposite direction of the both side surfaces 74 (the left and right direction of the paper surface of Fig. 2) Is the same as the position of the center axis of the tube 63 that is closest to the tube 74. The end of the barrier 64 at the center of the flow path may be located closer to the center of the flow path than the center axis of the tube 63 closest to the side surface 74 to which the barrier 64 is fixed.

The cleaning nozzle 65 is positioned above the pin group 62 in the vertical direction and ejects the cleaning liquid 101 toward the downward direction in the vertical direction. The cleaning nozzle 65 is installed in a cleaning pipe 66 extending from one side 74 to the other side 74. The cleaning liquid 101 is supplied from the cleaning tank outside the drawing to the cleaning pipe 66 and is injected from the cleaning pipe 66 through the cleaning nozzle 65. A plurality of cleaning pipes 66 are disposed between both end faces 73.

<Flow of Cleaning Solution>

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. 4 is a view showing 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. The EGR gas cooler 53 of the comparative example is not divided in the vertical direction in the pin group 62. That is, The second-stage pin group 82 and the third-stage pin group 83. In addition to the above points, in the EGR gas cooler 53 of the comparative example, And has the same configuration as the EGR gas cooler 53 of the 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 its direction of flow in the plane perpendicular to the tube 63 by contacting the tube 63. Here, if the EGR gas cooler 53 does not have the pin 80, the cleaning liquid 101 that has contacted the tube 63 flows along the outer circumferential surface of the tube 63 and then falls downward in the vertical direction by gravity do.

However, in the case of the EGR gas cooler 53 having the fin 80, the surface tension is applied to the cleaning liquid 101 passing between the fins 80, and the flow direction between the fins 80 is made by the tube 63 Flowing slowly while changing. On the other hand, since the cleaning liquid 101 which is attracted to the side surface 74 and flows along the side surface 74 does not mostly contact the fins 80 and does not contact the tube 63, the rate of flowing downward in the vertical direction is large . Therefore, the cleaning liquid 101 in the vicinity of the side surface 74 is easily drawn to the side, and the cleaning liquid 101 is more likely to gather in 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 74, causing a deflection in the flow of the cleaning liquid 101.

Next, the flow of the cleaning liquid 101 in the EGR gas cooler 53 of this embodiment will be described. 5 is a view showing the flow of the cleaning liquid 101 in the EGR gas cooler 53 of the present embodiment. In the EGR gas cooler 53 of the present embodiment as well, the cleaning liquid 101 injected toward the downward direction in the vertical direction from the cleaning nozzle 65 comes into contact with the tube 63 to change its flow direction, It is easy to gather.

However, the EGR gas cooler 53 according to the present embodiment has a barrier 64 provided along the side surface 74 thereof. Therefore, the cleaning liquid 101 flowing downward along the side surface 74 in the vertical direction is clogged by the barrier 64. Accordingly, in this embodiment, the cleaning liquid 101 can be prevented from flowing along the side surface 74, and the deflection of the flow of the cleaning liquid 101 can be suppressed. As a result, the EGR gas is prevented from being heated by the cleaning liquid 101 near the outlet of the EGR gas cooler 53, and the EGR gas can be sufficiently cooled.

As described above, in the present embodiment, the position of the flow path center side end portion of the barrier 64 in the opposite direction of the both side surfaces 74 is the same as the position of the end portion of the tube 64 closest to the side surface 74, (63). Therefore, the cleaning liquid 101 blocked by the barrier 64 is guided to the center of the flow path 75 beyond the tube 63 closest to the side surface 74. As a result, deflection of the flow of the cleaning liquid 101 can be further suppressed.

The barrier 64 positioned above the pin group 62 in the vertical direction among the plurality of the barriers 64 provided at the plurality of locations is constructed by connecting the cleaning liquid 101 directly sprayed from the cleaning nozzle 65 to the side surface 74, (62). Furthermore, the barrier 64 positioned below the pin group 62 in the vertical direction can suppress the flow rate of the cleaning liquid 101 flowing downward in the vertical direction. According to this, it is possible to prevent the cleaning liquid 101 in the vicinity of the side surface 74 from being pulled toward the side surface 74.

Here, in order to provide each of the barriers 64, a notch may be formed at a predetermined position of the fin 80, and a barrier 64 may be inserted into the notch. However, as in the present embodiment, the pin group 62 is separated in the vertical direction, and the separated pin group (the first stage pin group 81, the second stage pin group 82, the third stage pin group 83 ), It is not necessary to process the fin 80 into a complicated shape by providing the barrier 64 on the upper and lower sides in the vertical direction.

In the above, 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, even if the sectional shape of the barrier 64 is triangular and the inclined surface 67 inclined downward in the vertical direction from the side surface 74 toward the center of the flow path 75 good. 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. [ Therefore, the deflection of the flow of the cleaning liquid 101 can be further suppressed.

Here, the inclined surface 67 may have a curved shape when viewed in section. In this case as well, the flow direction of the cleaning liquid 101 can be changed to the direction toward the center of the flow path 75. Further, the barrier 64 may be formed in a plate shape, and may be provided so as to be inclined downward in the vertical direction from the side surface 74 toward the center of the flow path 75. In this case as well, 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 straight and extends from one end face 73 to the other end face 73 has been described, but the shape of the tube 63 is limited to this. For example, the tube 63 may be shaped like an S-shaped connection, and one tube 63 formed so as to be turned back a plurality of times in the flow path 75 may pass through a plurality of points of the pin group 62.

(Second Embodiment)

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

In the present embodiment, the EGR gas cooler 53 does not include the cleaning nozzle 65 for spraying the cleaning liquid 101, and does not clean the EGR gas. However, the EGR gas cooler 53 of this embodiment and the EGR gas cooler 53 of the first embodiment have the same configuration, except for these points. As described above, in this embodiment, a large amount of condensed water is generated in the EGR gas cooler 53 because the EGR gas containing a large amount of water is cooled by the EGR gas cooler 53 by cleaning the scrubber 52.

The condensed water flows in the EGR gas cooler 53 like the cleaning liquid 101 of the first embodiment. Since the EGR gas cooler 53 of the present embodiment also has the above-described barrier 64, it is possible to prevent the condensation water flowing along the side surface 74 from being blocked by the barrier 64 and causing deflection in the flow of the condensed water can do. As a result, the EGR gas is prevented from being heated by the condensed water near 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: Pin group
63: tube 64: barrier
65: Cleaning nozzle 66: Cleaning pipe
67: slope 73: section
74: side 75:
80: pin 81: first stage pin group
82: second stage pin group 83: third stage pin group
100, 200: engine system 101: cleaning liquid (internal fluid)

Claims (9)

A case having a pair of opposed side faces and a pair of side faces and a pair of side faces to define a flow path in which the EGR gas flows downward in the vertical direction,
A pin group formed of a plurality of pins located in the flow path and arranged parallel to the pair of end faces,
A tube through which the pin of the pin group passes and through which the refrigerant flows,
And a barrier disposed along the side surface and extending in the horizontal direction.
The method according to claim 1,
Wherein the barrier is disposed in at least one of a vertically upper end of the pin group, a lower vertical direction of the pin group, or a vertically upper end and a vertically lower end of the pin group.
3. The method of claim 2,
Wherein the pin group includes a first short pin group composed of a plurality of pins arranged in the same vertical direction position and a plurality of pins arranged in the same vertical direction position to each other, Gt; pin group &lt; / RTI &gt;
And said barrier is disposed between said first stage pin group and said second stage pin group.
4. The method according to any one of claims 1 to 3,
Wherein the barrier is positioned above the vertically upper end of the pin group in the vertical direction.
5. The method according to any one of claims 1 to 4,
Wherein the barrier has an inclined surface inclined downward in the vertical direction from the side surface toward the center of the flow path.
6. The method according to any one of claims 1 to 5,
The position of the center side end of the barrier disposed along the side face in the opposite direction of the pair of side faces is the same as the position of the center axis of the tube close to the side face or closer to the center of the channel than the position of the center axis EGR gas cooler.
7. The method according to any one of claims 1 to 6,
Further comprising a cleaning nozzle located above the pin group in the vertical direction and spraying the cleaning liquid downward in the vertical direction.
An engine system comprising an EGR gas cooler according to claim 7.
An engine system comprising: an EGR gas cooler according to any one of claims 1 to 6; and a scrubber disposed upstream of the EGR gas cooler and cleaning the EGR gas using a cleaning liquid.

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