WO2018194226A1

WO2018194226A1 - Egr cooler provided with pre-cooling zone

Info

Publication number: WO2018194226A1
Application number: PCT/KR2017/010637
Authority: WO
Inventors: 조형근
Original assignee: 주식회사 코렌스
Priority date: 2017-04-17
Filing date: 2017-09-26
Publication date: 2018-10-25
Also published as: KR101793198B1

Abstract

An EGR cooler, according to the present invention, comprises: a body cell of which two sides in the lengthwise direction are formed in the shape of ducts so that cooling water can be introduced to and discharged from the inside thereof; a plurality of gas tubes installed inside the body cell so as to be separated away from the inner surfaces of the body cell; an end plates coupled so as to cover a lengthwise end of the body cell and provided with an opening at a center part into which an end of the gas tubes are inserted by being fitted; and wave fins inserted inside the gas tubes to be in contact with an inner surface of the gas tubes, and of which one lengthwise end is installed so as to face an inlet on the gas tubes, wherein one lengthwise end of at least one wave fin from among the plurality of wave fins is positioned at a point separated away toward an outlet on the gas tubes from the point where the end plate is installed.

Description

EZR Cooler with Precooling Section

The present invention relates to an EG cooler that cools exhaust gas introduced into an exhaust gas recirculation system (EGR: Exhaust gas) with cooling water, and more particularly, in order for the exhaust gas to exchange heat with the cooling water. It relates to an EG cooler having a section previously exhaust gas is precooled.

In general, Exhaust Gas Recirculation (EGR) is a system in which a part of the exhaust gas is recycled back to the intake system to increase the concentration of CO 2 in the intake air, thereby lowering the temperature of the combustion chamber and thereby reducing the NOx.

On the other hand, the mechanism of NOx generation, in detail, consists of about 79% nitrogen, 21% oxygen and other trace elements. At room temperature, nitrogen and oxygen do not react with each other, but at high temperature (above about 1450 ° C), they react with each other to form nitrogen oxides (thermal NOx). In particular, diesel engines generate combustion by compression ignition method, and the compression ratio is getting higher due to the development of the material of the cylinder, thereby increasing the temperature of the combustion chamber. Increasing the combustion chamber temperature increases the efficiency of the thermodynamic engine, but a large amount of nitrogen oxides are generated due to the high temperature. These nitrogen oxides are the main harmful substances that destroy the global environment, causing acid rain, optical smog, respiratory disorders, and the like.

The principle of NOx reduction by EZR is to lower the maximum temperature of the combustion chamber by recirculating inert gas (steam, carbon dioxide, etc.), second, to prevent the atmosphere of nitrogen oxide formation by lean combustion, and To reduce the ignition delay and lower the local maximum temperature and pressure in the combustion chamber. On the other hand, in the diesel engine, unlike the gasoline, the NOx reduction mechanism by EGR has been reported that the reduction of the oxygen concentration is the root cause and the study that the flame temperature decrease is the cause. At this time, no conclusion about which is right is given, but the contribution of NOx reduction in oxygen concentration and flame temperature has recently been reported to be at the same level.

EZR is equipped with EZR cooler, which reduces NOx without increasing fuel economy and PM due to stricter diesel emission control, and installs a cooler (cooler) using coolant from the engine. It is a device that can be obtained.

In this case, the EZR cooler should be cooled to 700 ℃ to 200 ℃, so it must be heat-resistant and must be compactly designed to be installed inside the car. Should be minimized, and condensation is generated from exhaust gas during heat exchange and sulfuric acid is included in the condensate because it is susceptible to corrosion. Since particulate matter (PM) of the exhaust gas can block the inside of the passage, countermeasure against fouling is required.

With reference to the accompanying drawings will be described in detail with respect to the conventional EZR cooler.

1 is a perspective view of a conventional EZC cooler, FIG. 2 is a cross-sectional perspective view of a conventional EZC cooler, and FIG. 3 is a partial sectional view of a conventional EZC cooler.

In general, an EZR cooler includes a body cell 10 including a coolant inlet pipe 11 and a coolant outlet pipe 12 so that the coolant flows in and out, and a plurality of gases installed in the body cell 10 through which exhaust gas flows. A tube 20, a wave fin 30 inserted into the gas tube 20, and an end plate 40 fixing both ends of the plurality of gas tubes 20 are provided as basic components.

The wave fin 30 inserted into the gas tube 20 is a component for increasing the heat exchange efficiency by transferring the temperature of the exhaust gas introduced into the gas tube 20 to the side wall of the gas tube 20. Is in contact with the inner surface.

On the other hand, the wave fin 30 is installed to fill the entire inner space of the gas tube 20 to maximize the heat exchange efficiency, the end of the wave fin 30 (left end in Figure 3) is a gas tube The end plate 40 of the inner space of the 20 is extended to the combined portion. At this time, since the end plate 40 of the gas tube 20 is not mounted in contact with the coolant, the end portion of the gas tube 20 is overheated.

As such, when the overheating of the gas tube 20 occurs, not only does the boiling phenomenon of boiling water boil in the corresponding portion, but also a large amount of thermal stress is generated, there is a problem that the parts can be damaged.

The present invention has been proposed to solve the above problems, it is possible to prevent the phenomenon that the inlet side of the gas tube is overheated to prevent the cooling water boiling phenomenon and the thermal stress concentration phenomenon, to maximize the heat exchange amount to exhaust gas cooling An object of the present invention is to provide an EG cooler that can maintain high efficiency.

Easy R cooler according to the present invention for achieving the above object is formed in the duct shape of the both sides in the longitudinal direction open the body cell in which the coolant flows out; A plurality of gas tubes mounted in the body cell so as to be spaced apart from the inner surface of the body cell; An end plate coupled to cover the longitudinal end of the body cell and having an opening formed at a central portion thereof in which an end of the gas tube is inserted in a fitting manner; And a wave fin inserted into the gas tube to be in contact with the inner surface of the gas tube, the wave fin being mounted such that one longitudinal end thereof faces the inlet of the gas tube. Is located at a point spaced one end in the longitudinal direction from the point at which the end plate is mounted toward the outlet of the gas tube.

The separation distance between the longitudinal end of the wave fin and the end plate is set to less than twice the height of the gas tube internal flow path.

The plurality of gas tubes are formed in a rectangular tube shape having a width larger than the thickness thereof, and are stacked in the thickness direction, and the upper and lower wave fins have one end in the longitudinal direction from the point where the end plate is mounted. It is located at a point spaced towards the exit.

The wave fin further includes an extension portion extending from the longitudinal end toward the inlet of the gas tube and spaced apart from the inner surface of the gas tube.

All wave fins are located at a point where the longitudinal end is spaced away from the point at which the end plate is mounted toward the outlet of the gas tube.

The extension part is manufactured through a process of cutting the upper and lower one side in the longitudinal direction of the wave fin.

Since the inlet side of the gas tube is not overheated, the EG cooler according to the present invention can prevent cooling water boiling phenomenon and concentration of heat stress, and maximize the heat exchange rate to maintain high exhaust gas cooling efficiency. have.

1 is a perspective view of a conventional RG cooler.

2 is a cross-sectional perspective view of a conventional EZC cooler.

3 is a partial cross-sectional view of a conventional RG cooler.

4 is a partial cross-sectional view of an EG cooler according to the present invention.

Fig. 5 is a partial cross-sectional view of an EZR cooler according to a second embodiment of the present invention.

6 is a partial cross-sectional view of the third embodiment of an EZR cooler according to the present invention.

7 is a partial cross-sectional view of the fourth embodiment of an EZR cooler according to the present invention.

8 is an enlarged perspective view of a wave fin included in the fourth embodiment of an EZR cooler according to the present invention.

Hereinafter, an embodiment of an EG cooler having a precooling section according to the present invention will be described in detail with reference to the accompanying drawings.

The EG cooler according to the present invention is a device for transferring a high temperature exhaust gas with a low temperature cooling water and cooling it to a predetermined level, and then transferring the exhaust gas to an exhaust gas recirculation (EGR) system, as shown in FIG. 4. A plurality of gas tubes 200 mounted in the body cell 100 to be spaced apart from the inner side of the body cell 100 and the inner surface of the body cell 100 is formed in an open duct shape in both directions in the open duct shape And an end plate 400 coupled to cover the longitudinal end of the body cell 100 and having an opening formed at the center of the gas tube 200 in a fitting manner. Is inserted into the inside of the 200 is in contact with the inner surface of the gas tube 200 is mounted so that the longitudinal end (left end in Figure 4) toward the inlet (left end in Figure 4) of the gas tube 200 Wave pin 300 is provided as a basic component.

In this case, the EG cooler according to the present invention is not located at the point where the end plate 400 is mounted at one end in the longitudinal direction of the wave fin 300, but the gas tube from the point at which the end plate 400 is mounted. The biggest feature of the configuration is that it is located at a point spaced toward the exit of 200.

The high temperature exhaust gas exhausted from the engine is introduced into the gas tube 200 through an inlet formed at one side (left side in this embodiment) of the gas tube 200, as shown in the conventional EZR cooler shown in FIG. 3. When the wave fins 30 are installed throughout the inner space of the gas tube 20, the heat of the exhaust gas flowing into the inlet of the gas tube 20 is transferred to the gas tube 20 as it is riding the wave fins 30. In the gas tube 20, a portion of the gas tube 20 which is not in contact with the cooling water, that is, the portion where the end plate 40 is mounted, is overheated, and thus the water phenomena due to the cooling water boiling and the concentration of thermal stress are frequently generated.

However, the EZR cooler according to the present invention is located at a point spaced at a distance from one end in the longitudinal direction of the wave fin 300 to the rear (more specifically, toward the outlet of the gas tube 200, the right direction in FIG. 4). In this case, since an empty space A in which the wave fin 300 does not exist is provided at the inlet side of the internal flow path of the gas tube 200, the heat of the exhaust gas introduced into the inlet of the gas tube 200 is empty. While passing through (A), it is not quickly delivered to the gas tube 200, but is rapidly delivered to the gas tube 200 only when the wave fin 300 is mounted.

That is, the EG cooler according to the present invention is not heated to a high temperature from the inlet of the gas tube 200 when the exhaust gas flows into the gas tube 200, but is spaced a predetermined distance from the inlet of the gas tube 200. From (more specifically from the point where the longitudinal end of the wave fin 300 is located) is heated to a high temperature, the end plate 400 is mounted to prevent the phenomenon of overheating the site where the coolant is not smoothly contacted, Accordingly, there is an advantage that the problem of component damage due to cooling water boiling and concentration of thermal stress is prevented. In addition, the EG cooler according to the present invention is in contact with the wave fin 300 after the exhaust gas is slightly cooled while passing through the empty space A, that is, precooling the empty space A. Since it is used as a section, it is also possible to obtain the effect of reducing the thermal shock applied to the wave fin 300.

EZR cooler according to the present invention can reduce the cooling water boiling and thermal stress concentration as the size of the empty space (A) used as a pre-cooling section is large, and greatly reduces the thermal shock applied to the wave fin 300 Although it can be obtained, if the size of the empty space (A) is secured too large, the length of the wave fin 300 is shortened by that, there is a problem that the heat exchange amount between the exhaust gas and the cooling water is reduced. Therefore, the separation distance L between the longitudinal end of the wave fin 300 and the end plate 400 is a cross-sectional specification of the gas tube 200 or the flow rate of the exhaust gas, the wave fin 300 and the gas tube 200. It is preferable to select appropriately according to various conditions such as heat transfer coefficient of.

At this time, when the separation distance (L) between the longitudinal end of the wave fin 300 and the end plate 400 becomes twice the height (H) of the internal flow path of the gas tube 200, a portion of the empty space in contact with the coolant Since is sufficiently secured, the above-mentioned cooling water boiling phenomenon and thermal stress concentration prevention effect and wave fin 300 thermal shock reduction effect is no longer increased significantly. Therefore, the distance L between the longitudinal end of the wave fin 300 and the end plate 400 is preferably set to two times or less of the height H of the inner channel of the gas tube 200.

The plurality of gas tubes 200 included in the present invention are formed in a rectangular tube shape having a width larger than the thickness thereof, and are stacked in the thickness direction (up and down direction in this embodiment), and both ends of the longitudinal direction of all the gas tubes 200 are end portions. It is coupled to penetrate the central portion of the plate 400.

At this time, the coolant flowing into the body cell 100 is mainly discharged toward the gas tube 200 located in the center, the gas tube 200 located on the uppermost side and the gas tube 200 located on the lowermost side. Compared to the gas tube 200 positioned in the center, the cooling water boiling and thermal stress concentration, and the wave fin 300 thermal shock phenomenon may occur frequently.

Therefore, in the EG cooler according to the present invention, one end in the longitudinal direction of the upper and lower wave fins 300 is spaced toward the outlet of the gas tube 200 from the point where the end plate 400 is mounted. Located at the point, one end of the longitudinal wave fin 300 in the longitudinal direction may be set to be mounted to the point where the end plate 400 is mounted. Of course, if there is a risk that the cooling water boiling and thermal stress concentration and the wave fin 300 thermal shock phenomenon may occur in the gas tube 200 positioned in the middle, as shown in FIG. It should be set to be located at a point spaced toward the outlet of the gas tube 200.

FIG. 7 is a partial cross-sectional view of the fourth embodiment of the IR cooler according to the present invention, and FIG. 8 is an enlarged perspective view of the wave fin 300 included in the fourth embodiment of the IR cooler according to the present invention.

As the lengthwise end of the wave fin 300 moves away from the inlet of the gas tube 200, a large space A is secured to reduce cooling water boiling, concentration of thermal stress, and thermal shock of wave fin 300. However, the contact area between the exhaust gas and the wave fins 300 may be reduced, so that the exhaust gas cooling performance may be somewhat degraded.

Therefore, the EG cooler according to the present invention may be configured to increase the contact area between the exhaust gas and the wave fin 300 while reducing the cooling water boiling phenomenon, the thermal stress concentration phenomenon, and the thermal shock phenomenon of the wave fin 300. .

For example, the wave fin 300 may include an extension 310 extending from one end in the longitudinal direction toward the inlet of the gas tube 200 as shown in FIGS. 7 and 8. Exhaust gas introduced through the inlet of the gas tube 200 is first contacted with the extension 310 to transfer heat to the wave fin 300, which is directly connected to the gas tube 200. Since it is not in contact with the heat transmitted to the extension 310 is passed through the body of the wave fin 300 is transferred to the gas tube 200. That is, when the extension part 310 is additionally provided in the wave fin 300, the efficiency of transferring the heat of the exhaust gas to the gas tube 200 through the wave fin 300 is increased, and the end of the gas tube 200 is increased. Since the phenomenon in which the plate 400 is mounted is not overheated, it is possible to obtain an effect of improving the cooling performance of the exhaust gas while preventing the cooling water boiling phenomenon, the thermal stress concentration phenomenon, and the wave fin 300 thermal shock phenomenon. do.

In this case, the longer the extension length of the extension portion 310, the better the exhaust gas cooling performance, but if the extension length of the extension portion 310 is made too long, the end of the extension portion 310 outside the gas tube 200 There is a risk of protruding into the bar, the end of the extension 310 is preferably located at the point where the end plate is mounted in the inner space of the gas tube 200, as shown in FIG.

On the other hand, when the extension 310 is provided in the wave fin 300 as mentioned above, since the cooling performance of the exhaust gas can be maintained high, all the wave fin 300 is one end in the longitudinal direction of the end plate 400 It is preferably set to be located at a point spaced toward the outlet of the gas tube 200 from the mounting point.

In addition, the shape of the extension portion 310 may be formed in a flat plate shape as shown in this embodiment, or may be formed in a wave plate shape to further widen the contact area with the exhaust gas. That is, the shape of the extension 310 may be variously modified according to various conditions, a detailed description thereof will be omitted.

On the other hand, in order to manufacture the extension 310 separately to be coupled to one end in the longitudinal direction of the wave fin 300, not only takes a lot of time to manufacture the extension 310, but also takes a long time to combine the extension 310 There is a problem. In addition, if the extension portion 310 is manufactured separately and then coupled, the extension portion 310 may not be smoothly manufactured, which may interfere with the flow of the exhaust gas.

Therefore, the manufacturer may cut the upper and lower portions of one side in the longitudinal direction of the conventional wave fin 30 shown in FIG. 3 to process the wave fin 300 so that the remaining portion is the extension portion 310. As such, when the extension part 310 is formed by cutting the upper and lower sides of the wave fin 300 in the longitudinal direction, the extension part 310 may not only be easily manufactured, but also the exhaust gas may be smoothly flown. There is an advantage. In addition, since the conventional wave fin 30 can be recycled, there is an advantage that can reduce the waste of resources.

As mentioned above, although this invention was demonstrated in detail using the preferable Example, the scope of the present invention is not limited to a specific Example and should be interpreted by the attached Claim. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

Claims

Body cells in which both sides of the longitudinal direction are formed in an open duct shape and flow coolant therein;

A plurality of gas tubes mounted in the body cell so as to be spaced apart from the inner surface of the body cell;

An end plate coupled to cover the longitudinal end of the body cell and having an opening formed at a central portion thereof in which an end of the gas tube is inserted in a fitting manner; And

A wave fin inserted into the gas tube and in contact with an inner surface of the gas tube, the wave fin being mounted such that one longitudinal end thereof faces the inlet of the gas tube;

Including,

At least one of the plurality of wave fins is located at a point at which one longitudinal end is spaced from the point at which the end plate is mounted toward the outlet of the gas tube,

The wave fin further comprises an extension extending from the longitudinal end toward the inlet of the gas tube and spaced apart from the inner surface of the gas tube.
The method according to claim 1,

The separation distance between the longitudinal end of the wave fins and the end plate is less than twice the height of the inner channel of the gas tube cooler.
The method according to claim 1,

The plurality of gas tubes are formed in the shape of a square tube having a width larger than the thickness is laminated in the thickness direction,

The top and bottom wave fins are located in the zigzag cooler, characterized in that the longitudinal end is located at a point away from the point where the end plate is mounted toward the outlet of the gas tube.
The method according to claim 1,

And wherein all the wave fins are located at a point longitudinally spaced apart from the point at which the end plate is mounted toward the outlet of the gas tube.
The method according to claim 1,

The extension unit, an EG cooler, characterized in that the manufacturing process by cutting the upper and lower one side in the longitudinal direction of the wave fins.