exhaust gas cooler

Abstract

Exhaust gas cooler (2), comprising: a heat exchange tube (21) accommodated in the cooling water of an engine (1), through which exhaust gas from the engine (1) passes to exchange heat with the cooling water; and a plate (22) designed to attach the heat exchange tube (21) to the engine (1), wherein the heat exchange tube (21) comprises: a first pipe unit (211) configured to communicate with an inlet hole (121) for exhaust gas and to change a flow direction of the exhaust gas attracted to the inlet hole (121); a second pipe unit (212) configured to communicate with the first pipe unit (211) and to guide the exhaust gas drawn in by the first pipe unit (211) in one direction; and a third pipe unit (213) configured to communicate with an exhaust gas recirculation hole (122) and the second pipe (212) and to change a flow direction of the exhaust gas attracted by the second pipe unit (212) to guide the exhaust gas to the recirculation hole (122), wherein a heat dissipation fin (214) is provided in an inner channel of the second pipe unit (212) such that the heat dissipation fin (214) is not bent in the inner channel through which the exhaust gas passes.

Description

Background of the inventionTechnical field

[0001] Exemplary embodiments of the present invention relate to an exhaust gas cooler, and more particularly to an exhaust gas cooler attached to an engine in which an exhaust gas is recirculated into a combustion chamber so as to cool the recirculation exhaust gas of the engine. State of the art

[0002] In general, vehicle exhaust contains a large amount of harmful substances such as carbon monoxide, nitrogen oxides, and hydrocarbons. In particular, the production rate of pollutants such as nitrogen oxides increases when the temperature of an engine is increased.

[0003] Today, emissions regulations are becoming more stringent in every country. To comply with these stricter emissions regulations, vehicles are equipped with an exhaust gas recirculation (EGR) system to reduce pollutants such as nitrogen oxides contained in the exhaust gas.

[0004] The EGR device delivers exhaust gas of the vehicle along with mixed air into a combustion chamber of the engine, thereby reducing the temperature of the combustion chamber, thereby reducing an emission rate of harmful substances such as nitrogen oxides or sulfur oxides.

[0005] To achieve the above-mentioned purpose, the EGR device includes an exhaust gas cooler (EGR cooler) that reduces the temperature of the exhaust gas drawn into the combustion chamber, so that the temperature of the exhaust gas discharged from the combustion chamber can be reduced to a predetermined temperature before the exhaust gas is drawn into the combustion chamber.

[0006] Examples of a conventional exhaust gas cooler were proposed in KR 10 2012 0121224 A and US 2013 0213368 A1.

[0007] Referring to KR 10 2012 0121224 A, an exhaust gas cooler according to a first conventional art includes a heat exchange tube that cools exhaust gas using engine cooling water. The heat exchange tube is configured so that exhaust gas passes through the heat exchange tube in one direction. A heat dissipation fin is provided in the heat exchange tube so that a heat exchange area of ​​the exhaust gas in the heat exchange line can be increased.

[0008] Referring to US 2013 0213368 A, a second conventional exhaust gas cooler includes a heat exchange tube that cools exhaust gas using engine cooling water. The heat exchange tube is configured such that, in order to increase the length of an exhaust gas flow channel, the flow direction of the exhaust gas introduced into the heat exchange tube in one direction can be reversed to the opposite direction before the exhaust gas is discharged from the heat exchange tube.

[0009] However, conventional exhaust gas coolers are problematic because the heat exchange performance (cooling performance for cooling the exhaust gas) is reduced in a limited space. Specifically, the exhaust gas cooler according to the first conventional art includes the heat dissipation fin to improve heat exchange performance, but since the heat dissipation fin cannot have a curved structure, the heat exchange tube must be formed to extend in one direction. That is, an inlet and an outlet of the heat exchange tube are open in opposite directions on the same axis, and a flow channel connecting the inlet and outlet of the heat exchange tube is formed in a linear direction. Therefore, the length of the exhaust gas flow channel in the heat exchange tube is comparatively short, and the heat exchange performance is reduced.On the other hand, in the exhaust gas cooler according to the second conventional technique, in order to increase the length of the exhaust gas flow channel in the heat exchange tube and improve heat exchange performance, the heat exchange tube is configured so that the flow direction of the exhaust gas introduced into the heat exchange tube in one direction can be changed to the opposite direction before the exhaust gas is discharged from the heat exchange tube. In other words, the inlet and outlet of the heat exchange tube are open in the same direction. A flow channel connecting the inlet and outlet of the heat exchange tube is formed to extend from the inlet of the heat exchange tube in a linear direction, bend along a semicircular line, extend from the bent portion in one direction, and communicate with the outlet of the heat exchange tube.However, since the flow passage is rapidly changed in one direction, the pressure drop of the exhaust gas (the difference between the pressure of the exhaust gas at the inlet of the heat exchange tube and the pressure of the exhaust gas at the outlet of the heat exchange tube) increases, thereby reducing the heat exchange efficiency. Furthermore, since the heat exchange tube is bent, a separate heat dissipation fin cannot be provided in the heat exchange tube. As a result, the improvement in heat exchange performance is limited.

[0010] Further examples of exhaust gas coolers known to date can be found in EP 2 063 097 A1 and JP 2001 254 648 A. Description of the inventionTechnical problem

[0011] An embodiment of the present invention relates to an exhaust gas cooler capable of improving heat exchange performance in a limited space. Technical solution

[0012] The above objects and problems are solved by an exhaust gas cooler according to claim 1. Further embodiments emerge from the dependent claims. An exhaust gas cooler according to a first embodiment of the present invention may include a heat exchange tube accommodated in cooling water of an engine, through which exhaust gas of the engine passes to exchange heat with the cooling water; and a plate configured to attach the heat exchange tube to the engine.The heat exchange tube may include: a first tube unit configured to communicate with an exhaust gas inlet hole and change a flow direction of the exhaust gas attracted by the inlet hole; a second tube unit configured to communicate with the first tube unit and guide the exhaust gas attracted by the first tube unit in one direction; and a third tube unit configured to communicate with an exhaust gas recirculation hole and the second tube and change a flow direction of the exhaust gas attracted by the second tube unit to guide the exhaust gas to the recirculation hole. A heat dissipation fin may be provided in an inner channel of the second tube unit such that the heat dissipation fin is not bent in the inner channel through which the exhaust gas passes.

[0013] The heat dissipation fin may extend in one direction.

[0014] The first pipe unit and / or the third pipe unit can be detachably coupled to the second pipe unit.

[0015] The first pipe unit, the second pipe unit, and the third pipe unit may be accommodated in the cooling water.

[0016] The first tube unit and / or the third tube unit may comprise: a linear part having a flow channel extending in one direction; and a curved part extending from the linear part and having a curved flow channel, wherein a unidirectional additional heat dissipation fin is provided in an inner flow channel of the linear part.

[0017] An uneven surface may be formed in a side wall of the first pipe unit and / or the second pipe unit and / or the third pipe unit.

[0018] A second distance between a center point of an inlet of the first pipe unit and a center point of an outlet of the third pipe unit may be longer than a first distance between the center point of the inlet of the first pipe unit and a center point of an outlet of the first pipe unit and shorter than twenty times the first distance. The second distance may be longer than a third distance between a center point of an inlet of the third pipe unit and a center point of an outlet of the third pipe unit and shorter than twenty times the third distance.

[0019] The first tube unit and / or the third tube unit can be bent based on a predetermined radius of curvature. The radius of curvature can be greater than 6 mm and less than 30 mm.

[0020] The first tube unit and / or the third tube unit may be bent at a predetermined first angle from the second tube unit.

[0021] The first angle can be a right angle.

[0022] The first angle can be an obtuse angle.

[0023] The first tube unit and / or the third tube unit bent from the second tube unit may include: a first portion bent from the second tube unit at a first angle; and a second portion bent from the first portion at a predetermined second angle. The second angle may be an obtuse angle.

[0024] The first pipe unit may comprise a single first pipe unit, and a single flow channel may be formed in the first pipe unit. The second pipe unit may comprise a plurality of second pipe units, and a plurality of flow channels may be formed in the second pipe unit. The third pipe unit may comprise a single first pipe unit, and a single flow channel may be formed in the third pipe unit. The flow channel of the single first pipe unit may communicate with the flow channels of the plurality of second pipe units. The flow channel of the single third pipe unit may communicate with the flow channels of the plurality of second pipe units.

[0025] The first pipe unit can be configured such that a cross-sectional area of ​​the flow channel of the first pipe unit is equal to or greater than a sum of cross-sectional areas of the flow channels of the second pipe units. The third pipe unit can be configured such that a cross-sectional area of ​​the flow channel of the third pipe unit is equal to or greater than a sum of cross-sectional areas of the flow channels of the second pipe units.

[0026] The heat exchange tube may include a plurality of heat exchange tubes, and the plurality of heat exchange tubes may be arranged in a multi-stage structure to be spaced apart from each other.

[0027] A heat exchange tube provided in at least one stage among the plurality of heat exchange tubes may extend in a direction inclined to a stacking direction of the multi-stage heat exchange tubes and form a single column structure.

[0028] A heat exchange tube provided in at least one stage among the plurality of heat exchange tubes may include a plurality of heat exchange tubes arranged in a multi-stage structure to be spaced apart from each other in a direction inclined relative to a stacking direction of the multi-stage heat exchange tubes.

[0029] The heat exchange tube and plate may form an exterior or a structural unit and be installed in a cooling water flow channel of the engine.

[0030] The exhaust gas cooler may comprise: a housing having a cooling water inlet opening through which cooling water discharged from the engine is drawn into the housing, a cooling water receiving space for receiving cooling water drawn from the cooling water inlet opening, and a cooling water outlet opening configured to return cooling water from the cooling water receiving space to the engine, wherein the housing may be provided outside the engine, and the heat exchange tube and the plate may be provided in the cooling water receiving space of the housing. Beneficial effects

[0031] In an exhaust gas cooler according to the present invention, a heat exchange tube includes a first tube unit that changes the flow direction of the exchange from the extracted heat exchange tube, a second tube unit that guides exhaust gas extracted in a direction from the first tube unit, and a third tube unit that changes the flow direction of the exhaust gas extracted from the second tube unit and guides the exhaust gas out of the heat exchange tube. A heat dissipation fin is provided in the inner flow channel of the second tube unit. Therefore, the length of a flow channel of the exhaust gas passing through the heat exchange tube in a confined space is increased. The direction of the flow channel can be smoothly changed, thereby reducing the pressure drop of the exhaust gas. In addition, a heat exchange area of ​​the exhaust gas can be increased. Consequently, heat exchange performance in the confined space can be improved. Short description of the drawings Fig. 1 is a perspective view showing an exhaust gas cooler according to an embodiment of the present invention. Fig. 2 is an exploded perspective view of Fig. 1. Fig. 3 is a cross-sectional view along line II of Fig. 1. Fig. 4 is a cross-sectional view showing an exhaust gas cooler mounted on an engine of Fig. 1 shows. Fig. 5 to 7 are cross-sectional views showing other embodiments of a heat exchange tube of Fig. Show 1. Fig. 8 is an exploded perspective view showing an exhaust gas cooler according to another embodiment of the present invention. Fig. 9 is a cross-sectional view along the line II-II of Fig. . Fig. 10 to 13 are exploded perspective views showing exhaust gas coolers in accordance with other embodiments of the present invention. Fig. 14 to 15 are perspective sectional views showing exhaust gas coolers according to other embodiments of the present invention. Fig. 16 is an exploded perspective view showing an exhaust gas cooler according to still another embodiment of the present invention. Description of the embodiments

[0032] Hereinafter, an exhaust gas cooler according to the present invention will be described with reference to the accompanying drawings.

[0033] Fig. 1 is a perspective view illustrating an exhaust gas cooler according to an embodiment of the present invention, Fig. 2 is an exploded perspective view of Fig. 1, Fig. 3 is a cross-sectional view along line II of Fig. 1 and Fig. Fig. 4 is a cross-sectional view showing an exhaust gas cooler mounted on an engine of Fig. 1 shows.

[0034] With reference to the Fig. 1 to 4, the exhaust gas cooler 2 according to the embodiment of the present invention may include a heat exchange tube 21 accommodated in cooling water of the engine 1 and passing through the exhaust gas of the engine 1 to exchange heat with the cooling water, and may include a plate 22 provided for attaching the heat exchange tube 21 to the engine 1.

[0035] The heat exchange tube 21 may include a first tube unit 211 communicating with an exhaust gas inlet hole 121, a third tube unit 213 communicating with an exhaust gas recirculation hole 122, a second tube unit 212 connecting the first tube unit 211 and the third tube unit 213, and a heat dissipation fin 214 provided in an inner flow channel formed in the second tube unit 212.

[0036] The exhaust gas inlet hole 121 and the exhaust gas recirculation hole 122 provided in the engine 1 may be formed in the same plane at positions spaced from each other and may be open in the same direction.

[0037] Here, a direction from the exhaust gas inlet hole 121 to the exhaust gas recirculation hole 122 refers to the +x-axis direction (in the left direction in Fig. 4). A direction opposite to the +x-axis direction refers to the -x-axis direction (in the right direction in Fig. 4). A direction in which the exhaust gas inlet hole 121 and the exhaust gas inlet hole 122 are open refers to the +y-axis direction (in the upward direction in Fig. 4). A direction opposite to the +y-axis direction refers to the -y-axis direction (downward in Fig. 4). A direction perpendicular to the x-axis and the y-axis refers to the +z-axis direction (in the direction drawn into the sheet of Fig. 4). A direction opposite to the +z-axis direction refers to the -z-axis direction (in the direction emerging from the sheet of Fig. 4 emerges).

[0038] The first pipe unit 211 may be configured to change the flow direction of the exhaust gas drawn from the exhaust inlet hole 121 in the +y-axis direction to the +x-axis direction and guide the exhaust gas into the second pipe unit 212. In the case of the present embodiment, the first pipe unit 211 may be curved based on a predetermined radius of curvature (R) so that the exhaust gas flowing through the first pipe unit 211 can flow smoothly and evenly, reducing the pressure drop of the exhaust gas and increasing the flow velocity thereof, thereby improving the heat exchange efficiency.

[0039] The radius of curvature R of the first tube unit 211 is defined as the distance from a center of curvature O of the first tube unit 211 to the center of a flow channel (hereinafter referred to as "first flow channel") of the first tube unit 211. It is preferable that the radius of curvature R is greater than 6 mm to enable manufacturing of the first tube unit, and less than 30 mm to avoid a problem in which it is impossible to install the heat exchange tube 21 in a limited space due to an increase in the overall size of the heat exchange tube 21.

[0040] The first tube unit 211 may be formed from a single tube unit, in contrast to the second tube unit 212, which is formed from a plurality of tube units described later herein. Specifically, a single first flow channel is formed. In order to enable the single first flow channel to be connected to all the flow channels (hereinafter referred to as “second flow channels”) of the second tube units 212, the cross-sectional area of ​​the first flow channel may be equal to or greater than the sum of the cross-sectional areas of the second flow channels. In contrast to the present embodiment, when the first tube unit 211 is formed from a plurality of tube units (ie,When a plurality of first flow channels are formed, the sum of the cross-sectional areas of the first flow channels may be smaller than the cross-sectional area of ​​the exhaust inlet hole 121, and the resistance increases when exhaust gas is drawn from the exhaust inlet hole 121 into the first pipe unit 211. As a result, the pressure drop of the exhaust gas can be increased. In view of this, the first pipe unit 211 according to the present embodiment may be formed from a single pipe unit to mitigate the pressure drop of the exhaust gas in an inlet of the first pipe unit 211.

[0041] The first tube unit 211 may be removably coupled to the second tube unit 212 so that the heat exchange tube 21 may include the heat exchange tube 21 in the second tube unit 212, and the direction of the exhaust gas flow may be changed at the opposite ends of the second tube unit 212.

[0042] In order to facilitate the manufacturing process and reduce the manufacturing cost, the first pipe unit 211 may include a first first pipe piece 211A arranged on one side based on a first imaginary surface containing an exhaust gas flow passing through the first flow channel, and a second first pipe piece 211B arranged on the other side based on the first imaginary surface and coupled to the first first pipe piece 211A.

[0043] The second pipe unit 212 extends in one direction, allowing the exhaust gas flowing through the second pipe unit 212 to flow in one direction (the x-axis direction). Specifically, the second pipe unit 212 may be configured to maintain the flow direction of the exhaust gas extracted from the first pipe unit 211 in the +x-axis direction, and to discharge the exhaust gas from the second pipe unit 212 in the +x-axis direction and then guide it into the third pipe unit 213.

[0044] The second tube unit 212 may be formed from a plurality of tube units so that the heat exchange area thereof can be increased. The plurality of second tube units 212 may be stacked in a multi-tiered structure to be spaced from each other in the y-axis direction, or they may be stacked in a multi-column structure to be spaced from each other in the z-axis direction. In the present embodiment, the second tube units 212 may be stacked in the y-axis direction.

[0045] In order to facilitate the manufacturing process and reduce the manufacturing cost, the second pipe unit 212 may include a first second pipe piece 212A arranged on one side based on a second imaginary surface containing an exhaust gas flow passing through the second flow channel, and a second second pipe piece 212B arranged on the other side based on the second imaginary surface and coupled to the first second pipe piece 212A.

[0046] The third tube unit 213 may be formed symmetrically to the first tube unit 211 based on a third imaginary surface that is perpendicular to the x-axis and includes the center of the second tube unit 212.

[0047] The third pipe unit 213 may be configured to change the direction of the exhaust gas flow attracted by the second pipe unit 212 in the +x-axis direction to the -y-axis direction and guide the exhaust gas into the exhaust gas recirculation hole 122. In the case of the present embodiment, the third pipe unit 213 may be curved based on a predetermined radius of curvature (R) so that the exhaust gas flowing through the third pipe unit 213 can flow smoothly and evenly, reducing a pressure loss of the exhaust gas and increasing the flow velocity thereof, thereby improving the heat exchange efficiency.

[0048] The radius of curvature R of the third tube unit 213 is defined as the distance from a center of curvature O of the third tube unit 213 to the center of a flow channel (hereinafter referred to as “third flow channel”) of the third tube unit 213. It is preferable that the radius of curvature R is greater than 6 mm to make it possible to manufacture the third tube unit 213, and less than 30 mm to avoid a problem in which it is impossible to install the heat exchange tube 21 in a limited space due to an increase in the overall size of the heat exchange tube 21.

[0049] The third pipe unit 213 may be formed from a single unit in the same manner as the first pipe unit 211, so that a pressure drop of the exhaust gas at an outlet of the third pipe unit 213 can be mitigated. Specifically, a single third flow channel is formed. To enable the single first flow channel to be connected to the plurality of second flow channels, the cross-sectional area of ​​the third flow channel may be equal to or greater than the sum of the cross-sectional areas of the second flow channels.

[0050] The third tube unit 213 may be removably coupled to the second tube unit 212 so that the heat exchange tube 21 may include the heat exchange tube 21 in the second tube unit 212, and the direction of the exhaust gas flow at the opposite ends of the second tube unit 212 may be changed.

[0051] The heat dissipation fin 214 may be installed in the second tube unit 212 in a state where the first tube unit 211 and the third tube unit 213 are spaced apart from the second tube unit 212.

[0052] In order to facilitate the manufacturing process and reduce the manufacturing cost, the third pipe unit 213 may include a first third pipe piece 213A arranged on one side based on a fourth imaginary surface with an exhaust gas flow passing through the third flow channel, and a second third pipe piece 213B arranged on the other side based on the fourth imaginary surface and coupled to the first third pipe piece 213A.

[0053] In order to increase the length of a flow path for exhaust gas in a closed space and reduce the pressure drop of the exhaust gas, the heat exchange tube 21 is formed of the first tube unit 211, the second tube unit 212, and the third tube unit 213, wherein a y-axial first distance D1 between a center C11 of the inlet of the first tube unit 211 and a center C12 of an outlet of the first tube unit 211 may be the same as a y-axial third distance D3 between a center C31 of the inlet of the third tube unit 213 and a center C32 of the outlet of the third tube unit 213, and an x-axial second distance D2 between a center C11 of the inlet of the first tube unit 211 and a center C32 of the outlet of the third tube unit 213 may be longer than the first distance D1 or the third distance D3.In order to reduce the pressure loss of the exhaust gas and facilitate the manufacturing process, it is preferable that the second distance D2 is longer than the first distance D1 or the third distance D3 and shorter than 20 times the first distance D1 or 20 times the third distance D3, in order to avoid a problem in which it becomes impossible to install the heat exchange tube 21 in a closed space due to an increase in the overall size of the heat exchange tube 21.

[0054] The heat dissipation fin 214 may include a plurality of heat dissipation plates 214A extending in one direction and having a wave shape formed in Fig. 2, or have an offset type shown in Fig. 8. The heat dissipation fin 214 may have a rectangular overall shape such that the heat dissipation plates 214A are arranged parallel to each other at positions spaced apart from each other. As such, the heat dissipation fin 214 may generally have a shape extending in one direction.

[0055] Here, the heat dissipation fin 214 generally cannot have a curved shape because it is formed from wave or offset heat dissipation plates 214A. If the heat dissipation fin 214 extends in one direction and then bends, at least some flow passages in the heat dissipation fin 214 may be blocked, thereby reducing the heat exchange efficiency or causing a crack in the heat dissipation plates 214A. Considering this, the heat dissipation fin 214 according to the present embodiment may not be curved, may be provided in non-bent portions of the heat exchange tube 21, and may extend in one direction and be provided in a linear portion (in the second tube unit 212) of the heat exchange tube 21.

[0056] The plate 22 may include a body part 221 having a planar shape and forming the appearance of the plate 22, a first connection hole 222 formed in one end of the body part 221 and connecting the inlet of the first pipe unit 211 to the exhaust gas inlet hole 121, a second connection hole 223 formed in the other end of the body part 221 and connecting the outlet of the third pipe unit 213 to the exhaust gas recirculation hole 122, and a coupling hole 224 formed in the periphery of the body part 221 such that a fastening member (not shown) for fastening the plate 22 to the engine 1 is inserted into the coupling hole 224.

[0057] As in Fig. As shown in Figure 4, the heat exchange tube 21 and the plate 22 form the appearance of the exhaust gas cooler 2 with the above-mentioned configuration. The exhaust gas cooler 2 can be installed in a cooling water channel provided in the engine 1. In detail, the exhaust gas cooler 2 can be modularized into the heat exchange tube 21 and the plate 22, so that the exhaust gas cooler 2 can be removably coupled to the cooling water channel in the engine 1. Fig. 4, reference numeral 11 denotes a part of the engine 1 serving as a housing 23 of the exhaust gas cooler 2, which accommodates the cooling water therein. Reference numeral 12 denotes another part of the engine 1, which defines a cooling water accommodation space S together with the portion 11 of the engine 1 and serves as a cover 24 of the exhaust gas cooler 2, which has the exhaust gas inlet hole 121 and the exhaust gas recirculation hole 122. Thanks to the modularization, the number of parts, size, weight, manufacturing cost, and replacement cost of the exhaust gas cooler 2 can be reduced. Furthermore, the total number of parts, size, weight, manufacturing cost, and maintenance cost of the engine 1 mounted with the exhaust gas cooler 2 can be reduced.

[0058] The operation and effect of the exhaust gas cooler 2 according to the present embodiment will be described below.

[0059] Exhaust gas discharged from a combustion chamber (not shown) of the engine 1 may be guided to the exhaust inlet hole 121 formed in the engine 1 and then discharged from the exhaust inlet hole 121.

[0060] Exhaust gas discharged from the exhaust inlet hole 121 can be cooled while passing through the exhaust cooler 2. More specifically, the exhaust gas discharged from the exhaust inlet hole 121 can be cooled by the cooling water accommodated in the heat exchange tube 21 while passing through an internal flow channel of the heat exchange tube 21. Here, heat exchange between the exhaust gas and the cooling water can be generated not only in the second tube unit 212 of the heat exchange tube 21, but also in the first tube unit 211 and the third tube unit 213.

[0061] The exhaust gas cooled by the cooling water can be discharged from the heat exchange pipe 21 and drawn into the exhaust gas recirculation hole 122 formed in the engine 1.

[0062] The exhaust gas drawn into the exhaust gas recirculation hole 122 is drawn into the combustion chamber (not shown) of the engine 1 together with the mixing of air, thereby reducing the temperature of the combustion chamber (not shown), whereby the generation of nitrogen oxides or sulfur oxides can be prevented.

[0063] The exhaust gas cooler 2 according to the present embodiment includes the first tube unit 211 that changes the flow direction of the exhaust gas drawn into the heat exchange tube 21 in the +y-axis direction to the +x-axis direction, the second tube unit 212 that guides and discharges in the +x-axis direction an exhaust gas drawn in the +x-axis direction by the first tube unit 211, the third tube unit 213 that changes the flow direction of the exhaust gas drawn in the +x-axis direction by the second tube unit 212 to the -y-axis direction, and the heat dissipation fin 214 provided in the flow channel provided in the second tube unit 212. Therefore, the length of the flow channel of the exhaust gas passing through the heat exchange tube 21 is increased in a limited space. The direction of the flow channel can be slightly changed so that the pressure drop of the exhaust gas can be reduced.Additionally, the heat exchange surface of the exhaust gas can be increased. Consequently, the heat exchange performance between the exhaust gas and the cooling water in the confined space can be improved.

[0064] Furthermore, the exhaust gas cooler 2 is modularized into the heat exchange tube 21 and the plate 22 and is designed to be detachably installed in the cooling water passage of the engine 1. Therefore, the number of parts, size, weight, manufacturing cost, and replacement cost of the exhaust gas cooler 2 can be reduced. In addition, the total number of parts, size, weight, manufacturing cost, and maintenance cost of the engine 1 mounted with the exhaust gas cooler 2 can also be reduced.

[0065] In the present embodiment, the first tube unit 211 and the third tube unit 213 are curved at the predetermined radius of curvature R relative to the second tube unit 212. The heat dissipation fin 214 is provided in the inner flow channel of the second tube unit 212. However, other embodiments may also be used, as shown in the Fig. 5 to 7 shown.

[0066] Fig. Fig. 5 is a sectional view showing another embodiment of the heat exchange tube of Fig. 1 shows.

[0067] With reference to Fig. 5, the first tube unit 211 and / or the third tube unit 213 is bent from the second tube unit 212 at a preset first angle α based on the z-axis. The first angle α may be a right angle. The first angle α is defined as a small angle formed between the flow of the second tube 212 and any of the flows of the first and third tube units 211 and 213. In the embodiment shown in Fig. 5, the first tube unit 211 and the third tube unit 213 can be bent from the second tube unit 212 at the first angle α. The design and operating effects of the Fig. 5 may be practically the same as those of the above-described embodiment. Regarding the structure in which the first tube unit 211 and the third tube unit 213 are inserted into the first connecting hole 222 and the second connecting hole 223 of the plate 22 in the embodiment of Fig. 5, the direction (the y-axis direction) in which the first pipe unit 211 and the third pipe unit 213 extend is parallel to the direction (the y-axis direction) in which the first connection hole 22 and the second connection hole 223 extend. Therefore, compared with the above-mentioned embodiment, the first pipe unit 211 and the third pipe unit 213 can be more easily inserted into and connected to the first connection hole 222 and the second connection hole 223. The first pipe unit 211 and / or the third pipe unit 213 may include a linear part 2111, 2131 having a flow channel extending in one direction and a bent part 2112, 2132 extending from the linear part 2111, 2131 and having a bent flow channel. An additional heat dissipation fin 2151, 2152 extending in one direction may be provided in an inner flow channel of the linear part 2111, 2131.As in . Fig. 5, the first tube unit 211 may include a first linear part 2111 and a first bent part 2112. The third tube unit 213 may include a second linear part 2131 and a second bent part 2132. A first additional heat dissipation fin 2151 may be provided in the first linear part 2111. A second additional heat dissipation fin 2152 may be provided in the second linear part 2131. In this case, compared with the above-mentioned embodiment, a heat exchange area of ​​the exhaust gas passing through the heat exchange tube is increased, whereby the heat exchange performance can be further improved. The linear part 2111, 2131 and the additional heat dissipation fin 2151, 2152 provided in the linear part 2111, 2131 may also be provided in other embodiments.

[0068] Fig. Fig. 6 is a sectional view showing another embodiment of the heat exchange tube of Fig. 1 shows.

[0069] With reference to Fig. 6, the first tube unit 211 and / or the third tube unit 213 is bent by the second tube unit 212 at a preset first angle α based on the z-axis. The first angle α may be an obtuse angle. In the present embodiment, the first tube unit 211 and the third tube unit 213 may be bent by the second tube unit 212 at the first angle α. The configuration and operating effects of the Fig. 6 can be practically the same as those of the embodiments described above. In comparison to the embodiment shown in Fig. 5, the flow direction of the exhaust gas flowing through the first pipe unit 211 and the third pipe unit 213 can be changed more smoothly.

[0070] Fig. Fig. 7 is a sectional view showing another embodiment of the heat exchange tube of Fig. 1 shows.

[0071] With reference to Fig. 7, the first tube unit 211 and / or the third tube unit 213 is bent by the second tube unit 212 at a preset first angle α based on the z-axis. The first angle α may be an obtuse angle. Of the first tube unit 211 and the third tube unit 213, the tube unit bent by the second tube unit 212 may have a first section P1 bent by the second tube unit 212 at the first angle α based on the z-axis, and a second section P2 bent by the first section P1 at a preset second angle β based on the z-axis. The second angle β may be an obtuse angle. The second angle β is defined as a small angle formed between a flow of the first section P1 and a flow of the second section P2. In the embodiment shown in Fig. 7, the first and third tube units 211 and 213 may have a first section P1 bent from the second tube unit 212 at the first angle α, and a second section P2 bent from the first section P1 at the second angle β. The design and operating effects of the Fig. 7 are practically the same as those of the above-described embodiments. Regarding the structure in which the first tube unit 211 and the third tube unit 213 are inserted into the first connecting hole 222 and the second connecting hole 223 of the plate 22 in the embodiment of Fig. 7, the direction (the y-axis direction) in which the first tube unit 211 and the third tube unit 213 extend is parallel to the direction (the y-axis direction) in which the first connection hole 22 and the second connection hole 223 extend. Therefore, compared to the above-mentioned embodiments, the first tube unit 211 and the third tube unit 213 can be more easily inserted into and coupled with the first connection hole 222 and the second connection hole 223.

[0072] In the case of the present embodiment, the second pipe unit 212 is formed from the first second pipe piece 212A and the second second pipe piece 212B, which are coupled to each other, and the first pipe unit 211 and the third pipe unit 213 are removably coupled to the second pipe unit 212. However, other embodiments may also exist, as shown in the Fig. 8 to 13.

[0073] Fig. 8 is an exploded perspective view illustrating an exhaust gas cooler according to another embodiment of the present invention. Fig. 9 is a sectional view along the line II-II of Fig. 8.

[0074] With reference to the Fig. 8 and Fig. 9, the second tube unit 212 may have an integrated structure, and the first tube unit 211 and the third tube unit 213 may be removably coupled to the second tube unit 212. The heat dissipation fin 214 may be inserted into the second flow channel in the discharge direction of the second flow channel in a state in which the first and / or third tube units 211 and 213 are separated from the second tube unit 212. The configuration and operating effects of the Fig. 8 and Fig. 9 may be practically the same as those of the above-described embodiments. However, in this case, unlike the above-mentioned embodiments, a coupling surface between the first second pipe section 212A and the second second pipe section 212B can be removed, and a coupling surface between the first pipe unit 211 and the second pipe unit 212 can be reduced, and a coupling surface between the third pipe unit 213 and the second pipe unit 212 can be reduced. Therefore, exhaust gas can be prevented from passing through the coupling surfaces to the cooling water, or the cooling water can be prevented from leaking through the coupling surfaces to the exhaust gas. Fig. 8 and Fig. 9, the heat exchange area can be reduced because the second tube unit 212 has an integrated structure. Taking this into account, an uneven surface E can be formed in a side wall of the first tube unit 211 and / or the second tube unit 212 and / or the third tube unit 213. As shown in Fig. As shown in Fig. 9, the uneven surface E may be formed such that an inner surface of the sidewall in which the uneven surface E is formed is convex and concave, and an outer surface of the sidewall is also convex and concave. The uneven surface E can increase the heat exchange area between the heat exchange tube 21 and the exhaust gas and increase the heat exchange area between the heat exchange tube 21 and the cooling water, thereby improving heat exchange performance. Furthermore, the uneven surface E can induce turbulence in the exhaust gas and the cooling water, thereby further improving heat exchange performance. The uneven surface E having such a structure may also be formed in other embodiments.

[0075] Fig. 10 is an exploded perspective view illustrating an exhaust gas cooler according to another embodiment of the present invention.

[0076] With reference to Fig. 10, the second tube unit 212 may have an integrated structure. The first or third tube unit 211 and 213 may be formed integrally with the second tube unit 212. The other of the first or third tube units 211 and 213 may be removably coupled to the second tube unit 212. The heat dissipation fin 214 may be inserted into the second flow channel in the discharge direction of the second flow channel in a state in which the corresponding one of the first and third tube units 211 and 213 is separated from the second tube unit 212. The configuration and operating effects of the Fig. 10 are practically the same as those of the above-described embodiments. However, in this case, compared to the above-mentioned embodiments, the coupling areas between the first pipe unit 211, the second pipe unit 212, and the third pipe unit 213 can be further reduced. As a result, exhaust gas can be more reliably prevented from passing through the coupling surfaces to the cooling water, or the cooling water can be more reliably prevented from passing through the coupling surfaces to the exhaust gas.

[0077] Fig. 11 is an exploded perspective view illustrating an exhaust gas cooler according to another embodiment of the present invention.

[0078] With reference to Fig. 11, the second pipe unit 212 may include a first second pipe section 212A disposed on one side of a fifth imaginary surface inclined relative to the extending direction of the second pipe unit 212, and a second second pipe section 212B disposed on the other side of the fifth imaginary surface and coupled to the first second pipe section 212A. The first pipe unit 211 may be integrally formed with the first second pipe section 212A. The third pipe unit 213 may be integrally formed with the second second pipe section 212B.In this embodiment, the heat dissipation fin 214 may be provided in the internal flow channel of the second tube unit 212 such that, in a state where the first second tube piece 212A and the second second tube piece 212B are separated from each other, one end of the heat dissipation fin 214 is inserted into the first second tube piece 212A and the other end of the heat dissipation fin 214 is inserted into the second second tube piece 212B. The configuration and operating effects of the heat dissipation fin 214 shown in FIG. Fig. 11 are practically the same as those shown in Fig. 10 described embodiment.

[0079] Fig. 12 and Fig. 13 are exploded perspective views illustrating exhaust gas coolers in accordance with other embodiments of the present invention.

[0080] With reference to Fig. 12 or Fig. 13, the heat exchange tube 21 may include a first heat exchange tube piece 21A disposed on one side of a sixth imaginary surface containing an exhaust gas flow passing through the heat exhaust tube 21, and a second heat exchange tube piece 21B disposed on the other side of the sixth imaginary surface and coupled to the first heat exchange tube piece 21A. The first heat exchange tube piece 21A may have an integrated structure and include a first portion 211a of the first tube unit 211, a first portion 212a of the second tube unit 212, and a first portion 213a of the third tube unit 213. The second heat exchange tube piece 21B may have an integrated structure and include a second portion 211b of the first tube unit 211, a second portion 212b of the second tube unit 212, and a second portion 213b of the third tube unit.The heat dissipation fin 214 can be installed in the second flow channel of the second tube unit 212 by disposing the heat dissipation fin 214 between the first heat exchange tube piece 21A and the second heat exchange tube piece 21B when the first heat exchange tube piece 21A is coupled to the second heat exchange tube piece 21B. The configuration and operating effects of the heat exchanger shown in FIG. Fig. 12 or the embodiment shown in Fig. 13 are practically the same as those in Fig. 10 shown embodiment.

[0081] In the case of the present embodiment, a single heat exchange tube 21 is provided, but other embodiments may also be provided, as shown in the Fig. 14 and Fig. 15 is shown.

[0082] Fig. 14 is a perspective cross-sectional view illustrating an exhaust gas cooler according to another embodiment of the present invention.

[0083] With reference to Fig. 14, a plurality of heat exchange tubes 21 are provided. The heat exchange tubes 21 are stacked in a multi-stage structure to be spaced apart from each other in the y-axis direction. A heat exchange tube 21 provided at least one stage below the heat exchange tubes 21 may extend in the z-axis direction to have a single columnar structure. The design and operating effects of the heat exchange tubes 21 shown in Fig. The embodiments shown in Figure 14 may be virtually the same as those of the above-described embodiments. However, in this case, the heat exchange area between the exhaust gas and the cooling water is increased, so that the heat exchange performance can be improved.

[0084] Fig. 15 is a perspective sectional view illustrating an exhaust gas cooler according to another embodiment of the present invention.

[0085] With reference to Fig. 15, a plurality of heat exchange tubes 21 are provided. The heat exchange tubes 21 are stacked in a multi-stage structure to be spaced apart from each other in the y-axis direction. Heat exchange tubes 21 may be provided at least one stage below the heat exchange tubes 21 and arranged in a multi-column structure to be spaced apart from each other in the z-axis direction. The configuration and operating effects of the heat exchange tubes 21 shown in Fig. The embodiment shown in Figure 15 may be virtually the same as those of the above-described embodiments. However, in this case, the heat exchange area between the exhaust gas and the cooling water is further increased, so that the heat exchange performance can be further improved.

[0086] Although not shown, a plurality of heat exchange tubes 21 may be provided in a single step structure or a single column structure.

[0087] In the case of the present embodiment, the exhaust gas cooler 2 may be modularized into the heat exchange tube 21 and the plate 22 and installed in the cooling water passage in the engine 1. However, there may be another embodiment as shown in Fig. 16 is shown.

[0088] Fig. 16 is an exploded perspective view illustrating an exhaust gas cooler according to another embodiment of the present invention.

[0089] With reference to Fig.16, the exhaust gas cooler 2 may include the heat exchange tube 21, the plate 22, and a housing 23 disposed outside the engine 1 and accommodating the heat exchange tube 21 and the plate 22. The housing 23 may include a cooling water inlet port 231 through which cooling water discharged from the engine 1 is drawn into the housing 23, a cooling water receiving space S that receives cooling water drawn by the cooling water inlet port 231, and a cooling water outlet port 232 that returns cooling water from the cooling water receiving space S to the engine 1. The heat exchange tube 21 and the plate 22 may be provided in the cooling water receiving space S of the housing 23. In this case, the exhaust gas cooler 2 may be modularized into the heat exchange tube 21, the plate 22, and the housing 23, and removably attached to the outer surface of the engine 1. Therefore, the degree of freedom of the design of the exhaust gas cooler 2 itself can be improved and the maintenance of the exhaust gas cooler can be facilitated.In this case, the exhaust gas cooler 2 may further comprise a cover 24 covering the cooling water receiving space S of the housing 23, a first sealing element 25 disposed between the housing 23 and the plate 22, and a second sealing element 26 disposed between the plate 22 and the cover 24.

[0090] In the present embodiment, the heat exchange tube 21 can be applied to the exhaust gas cooler 2, in which cooling water flows outside the heat exchange tube 21 and exhaust gas passes through the interior of the heat exchange tube 21, whereby exhaust gas can be cooled by cooling water. Additionally, the heat exchange tube 21 can be applied to other heat exchange devices (not shown) in which the first fluid flows outside the heat exchange tube 21 and the second fluid flows through the interior of the heat exchange tube 21, whereby any one of the first fluid and the second fluid can be cooled by the other of the first fluid and the second fluid. Industrial applicability

[0091] The present invention can provide an exhaust gas cooler capable of improving heat exchange performance in a limited space.

Claims

[1] Exhaust gas cooler (2), comprising: a heat exchange tube (21) accommodated in the cooling water of an engine (1), through which exhaust gas from the engine (1) passes to exchange heat with the cooling water; and a plate (22) designed to attach the heat exchange tube (21) to the engine (1), wherein the heat exchange tube (21) comprises: a first pipe unit (211) configured to communicate with an inlet hole (121) for exhaust gas and to change a flow direction of the exhaust gas attracted to the inlet hole (121); a second pipe unit (212) configured to communicate with the first pipe unit (211) and to guide the exhaust gas drawn in by the first pipe unit (211) in one direction; and a third pipe unit (213) configured to communicate with an exhaust gas recirculation hole (122) and the second pipe (212) and to change a flow direction of the exhaust gas attracted by the second pipe unit (212) to guide the exhaust gas to the recirculation hole (122), wherein a heat dissipation fin (214) is provided in an inner channel of the second pipe unit (212) such that the heat dissipation fin (214) is not bent in the inner channel through which the exhaust gas passes. [2] Exhaust gas cooler (2) according to claim 1, wherein the heat dissipation fin (214) extends in one direction. [3] Exhaust gas cooler (2) according to claim 2, wherein the first pipe unit (211) and / or the third pipe unit (213) is detachably coupled to the second pipe unit (212). [4] Exhaust gas cooler (2) according to claim 1, wherein the first pipe unit (211), the second pipe unit (212), and the third pipe unit (213) are accommodated in the cooling water. [5] Exhaust gas cooler (2) according to claim 4, wherein the first pipe unit (211) and / or the third pipe unit (213) comprises: a linear part (2111, 2131) having a flow channel extending in one direction; and a curved part (2112, 2132) extending from the linear part (2111, 2131) and having a curved flow channel, wherein an additional heat dissipation fin (2151, 2152) extending in one direction is provided in an inner flow channel of the linear part (2111, 2131). [6] Exhaust gas cooler (2) according to claim 4, wherein an uneven surface (E) is formed in a side wall of the first pipe unit (211) and / or the second pipe unit (212) and / or the third pipe unit (213). [7] Exhaust gas cooler (2) according to claim 1, wherein a second distance (D2) between a center point (C11) of an inlet of the first pipe unit (211) and a center point (C32) of an outlet of the third pipe unit (213) is longer than a first distance (D1) between the center point (C11) of the inlet of the first pipe unit (211) and a center point (C12) of an outlet of the first pipe unit (211) and is shorter than twenty times the first distance (D1), and wherein the second distance (D2) is longer than a third distance (D3) between a center point (C31) of an inlet of the third pipe unit (213) and a center point (C32) of an outlet of the third pipe unit (213) and is shorter than twenty times the third distance (D3). [8] Exhaust gas cooler (2) according to claim 1, wherein the first pipe unit and / or the third pipe unit is bent based on a predetermined radius of curvature (R), and where the radius of curvature (R) is greater than 6mm and less than 30mm. [9] Exhaust gas cooler (2) according to claim 1, wherein the first pipe unit and / or the third pipe unit is bent at a predetermined first angle (α) from the second pipe unit (212). [10] Exhaust gas cooler (2) according to claim 9, wherein the first angle (α) is a right angle. [11] Exhaust gas cooler (2) according to claim 9, wherein the first angle (α) is an obtuse angle. [12] Exhaust gas cooler (2) according to claim 11, wherein the first pipe unit (211) and / or the third pipe unit (213) bent from the second pipe unit (212) comprises: a first section (P1) bent from the second tube unit (212) at the first angle (α); and a second portion (P2) bent from the first portion (P1) at a predetermined second angle (β), where the second angle (β) is an obtuse angle. [13] Exhaust gas cooler (2) according to claim 1, wherein the first pipe unit (211) comprises a single first pipe unit and a single flow channel is formed in the first pipe unit (211), wherein the second pipe unit (212) comprises a plurality of second pipe units and a plurality of flow channels are formed in the second pipe unit (212), wherein the third pipe unit (213) comprises a single first pipe unit and a single flow channel is formed in the third pipe unit (213), wherein the flow channel of the single first pipe unit (211) is connected to the flow channels of the plurality of second pipe units (212), and wherein the flow channel of the single third pipe unit (213) is connected to the flow channels of the plurality of second pipe units (212). [14] Exhaust gas cooler (2) according to claim 13, wherein the first pipe unit (211) is designed such that a cross-sectional area of ​​the flow channel of the first pipe unit (211) is equal to or greater than a sum of cross-sectional areas of the flow channels of the second pipe units (212), and wherein the third pipe unit (213) is designed such that a cross-sectional area of ​​the flow channel of the third pipe unit (213) is equal to or greater than a sum of cross-sectional areas of the flow channels of the second pipe units (212). [15] The exhaust gas cooler (2) according to claim 1, wherein the heat exchange tube (21) comprises a plurality of heat exchange tubes, and the plurality of heat exchange tubes (21) are arranged in a multi-stage structure to be spaced apart from each other. [16] The exhaust gas cooler (2) according to claim 15, wherein a heat exchange tube (21) provided in at least one stage among the plurality of heat exchange tubes (21) extends in a direction inclined with respect to a stacking direction of the multi-stage heat exchange tubes (21) and forms a single column structure. [17] The exhaust gas cooler (2) according to claim 15, wherein a heat exchange tube (21) provided in at least one stage among the plurality of heat exchange tubes (21) comprises a plurality of heat exchange tubes (21) arranged in a multi-stage structure to be spaced apart from each other in a direction inclined relative to a stacking direction of the multi-stage heat exchange tubes (21). [18] Exhaust gas cooler (2) according to claim 1, wherein the heat exchange tube (21) and the plate (22) form an exterior and are installed in a cooling water flow channel of the engine (1). [19] Exhaust gas cooler (2) according to claim 1, further comprising: a housing (23) with a cooling water inlet opening (231) through which cooling water discharged from the engine (1) is drawn into the housing (23), a cooling water receiving space (S) for receiving cooling water drawn from the cooling water inlet opening (231), and a cooling water outlet opening (232) designed to return cooling water from the cooling water receiving space (S) to the engine (1), wherein the housing (23) is provided outside the engine (1) and the heat exchange tube (21) and the plate (22) are provided in the cooling water receiving space (S) of the housing (23).

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