An EGR cooler

Abstract

The present invention relates to an EGR cooler, which comprises a housing, an air inlet hood, an air outlet hood and cooling pipes. Both ends of the housing are connected with mounting plates. A plurality of cooling pipes are provided and are all arranged between the two mounting plates. The air inlet hood is connected to one end of the housing, and the air outlet hood is connected to the other end of the housing. A water inlet pipe and a water outlet are connected to the surface of the housing. The water inlet pipe is arranged at a position of the housing close to the air outlet hood. A heating assembly is arranged in the water inlet pipe. The heating assembly comprises a first heating wire and a controller. The first heating wire is connected to the outer wall of the water inlet pipe. The heating temperature of the first heating wire is lower than the exhaust gas temperature. A heat preservation cover is arranged on the outer wall of the water inlet pipe. The first heating wire is located inside the heat preservation cover. The controller is connected to the surface of the housing. The heating wire is electrically connected to the controller. The present invention improves the cooling effect of the cooler.

Description

Technical Field

[0001] The present invention relates to the technical field of coolers, and more particularly to an EGR cooler. Background Art

[0002] This cooler is a device used to cool a part of the exhaust gas returned to the engine cylinder. In order to reduce the content of nitrogen oxides in vehicle exhaust, a part of the exhaust gas needs to be returned to the engine cylinder. The exhaust gas temperature is as high as 600 °C, and it must be cooled down before entering the engine intake system. Thus, the exhaust gas recirculation cooler came into being.

[0003] Chinese Patent with Publication No. CN112577341A discloses a cast housing type EGR cooler. Its intake joint is connected to a telescopic structure with a corrugated pipe and a sleeve. The outer circumference of the telescopic structure is fixedly connected to the input end flange cover. The input end flange cover is bolted to one end of the cast tube shell through an input end gasket. The other end of the tube shell is bolted to a fixed structure and an output end flange cover with an output pipe joint through an output end sealing ring; the telescopic structure is welded to the tube sheet at one end of the tube bundle, and the tube sheet at the other end of the tube bundle is welded to the fixed structure. In the present invention, a fixed structure is arranged at one end of the tube bundle and a telescopic structure is arranged at the other end, which solves the dislocation formed between the tube shell and the tube bundle due to thermal expansion and contraction. In the telescopic structure, the flexible structure of the double-layer corrugated pipe is used to compensate the axial displacement of the heat exchange core body, reducing the influence of thermal expansion and contraction on the heat exchange core body. The double-layer corrugated pipe is placed at the intake end, combined with the structure of the housing water inlet pipe, increasing the water flow space and ensuring the uniformity of water flow.

[0004] Regarding the above related technologies, the inventor believes that the exhaust gas in the tube bundle will liquefy when cooled. The liquefaction of the high-temperature exhaust gas is mainly related to the temperature of the coolant. The greater the temperature difference between the coolant and the exhaust gas, the easier the exhaust gas is to liquefy. The exhaust gas will appear in the tube bundle in the form of water droplets. When the water droplets stay in the tube bundle and absorb heat when encountering high-temperature exhaust gas, condensate will adhere to the inner wall of the tube bundle, which is the reason for the generation of carbon deposits. The cooler is prone to block the tube bundle after long-term use. The position of the tube bundle close to the water inlet pipe contacts the cooling water first, and the temperature of the cooling water is the lowest at that time. Therefore, the position where the exhaust gas liquefies is concentrated in the area near the water inlet pipe of the cooling tube, thereby reducing the cooling effect of the cooler. Summary of the Invention

[0005] In order to improve the cooling effect of the cooler, the present application provides an EGR cooler.

[0006] The EGR cooler provided by the present application adopts the following technical solutions:

[0007] An EGR cooler includes a housing, an air inlet hood, an air outlet hood and cooling tubes. Installation plates are connected to both ends of the housing. A number of cooling tubes are provided and are all arranged between the two installation plates. The air inlet hood is connected to one end of the housing, and the air outlet hood is connected to the other end of the housing. A water inlet pipe and a water outlet are connected to the surface of the housing. The water inlet pipe is arranged at a position of the housing close to the air outlet hood. A heating component is arranged in the water inlet pipe. The heating component includes a first heating wire and a controller. The first heating wire is connected to the outer wall of the water inlet pipe. The heating temperature of the first heating wire is lower than the exhaust gas temperature. A heat preservation cover is arranged on the outer wall of the water inlet pipe. The first heating wire is located inside the heat preservation cover. The controller is connected to the surface of the housing. The first heating wire is electrically connected to the controller.

[0008] By adopting the above technical solution, when it is necessary to heat the coolant, the staff uses the controller to energize the first electric heating wire, so that the first electric heating wire generates heat and transfers it to the pipe wall of the water inlet pipe. The coolant exchanges heat with the heated water inlet pipe before entering the housing, achieving the effect of heating the coolant. The staff uses the controller to control the temperature of the first heating wire to control the temperature of the coolant. The heated coolant contacts the cooling tubes and exchanges heat with the high-temperature exhaust gas through the cooling tubes, reducing the temperature difference between the coolant and the high-temperature exhaust gas, reducing the possibility of liquefaction of the high-temperature exhaust gas in the cooling tubes, thereby reducing the accumulation of carbon deposits, keeping the cooling tubes unobstructed as much as possible, and improving the cooling effect of the cooler.

[0009] Optionally, the cooling tubes are arranged obliquely. The height of the end of the cooling tube close to the air inlet hood is higher than the height of the end of the cooling tube close to the air outlet hood. A collection box for collecting waste liquid is connected to the air outlet hood.

[0010] By adopting the above technical solution, it is inevitable that the high-temperature exhaust gas liquefies in the cooling tubes. The liquefied exhaust gas flows along the inclined direction of the cooling tubes until it enters the collection box, reducing the possibility of the liquefied exhaust gas staying in the cooling tubes and further reducing the occurrence of carbon deposition.

[0011] Optionally, a second heating wire is connected to the installation plate close to the air outlet hood. A waterproof tube is wrapped on the surface of the second heating wire. The second heating wire is electrically connected to the controller. The operating temperature of the second heating wire is lower than the exhaust gas temperature.

[0012] By adopting the above technical solution, the staff uses the controller to energize the second heating wire, so that the second heating wire generates heat and transfers the heat to the installation plate close to the air outlet hood, heating the area near the cooling tubes close to this installation plate. Thus, the temperature difference between the cooling tubes and the high-temperature exhaust gas in this area is shortened, and the possibility of liquefaction of the high-temperature exhaust gas is further reduced.

[0013] Optionally, the air outlet hood is arranged in a frustum shape, the diameter of the air outlet end of the air outlet hood is smaller than that of the air inlet end, a collection groove is formed on the inner wall of the air outlet hood, a guiding ring is connected to the inner wall of the air outlet hood, the guiding ring is used for guiding the waste liquid in the cooling pipe to flow into the collection groove, a collection hole is formed at the lowest position of the collection groove, and the collection hole communicates with the collection box.

[0014] By adopting the above technical solution, due to the influence of waste gas liquefaction, after the high-temperature waste gas passes through the cooling pipe, it itself carries water vapor. The frustum-shaped setting of the air outlet hood enables more high-temperature waste gas to contact the inner wall of the air outlet hood. After the waste gas contacts the air outlet hood, the water vapor in the waste gas adheres to the air outlet hood, forms a liquid and converges to the lowest position of the collection groove, and finally flows into the collection box through the collection hole, realizing the effect of automatically collecting liquefied waste gas.

[0015] Optionally, the collection box is connected to the lowest position on the surface of the air outlet hood, an overflow pipe is connected to the collection box, the overflow pipe is arranged obliquely, a gas-blocking liquid is arranged in the collection box, the height of the water inlet end of the overflow pipe is lower than that of the water outlet end of the overflow pipe, and the water inlet end of the overflow pipe is located in the gas-blocking liquid.

[0016] By adopting the above technical solution, there is a possibility that the waste gas enters the collection box from the collection hole. The gas-blocking liquid is used to prevent the waste gas from leaking from the overflow pipe. At the same time, the gas-blocking liquid is converged by the liquefied waste gas, and the water surface rises. When it reaches the highest position of the overflow pipe, it flows out from the overflow pipe.

[0017] Optionally, a plurality of heat dissipation ring plates are connected to the surface of the air outlet hood.

[0018] By adopting the above technical solution, the heat dissipation ring plates are used to increase the heat dissipation area of the air outlet hood, so that the air outlet hood is maintained within a certain temperature range. In this way, it is more conducive to the heat exchange of the waste gas and the collection of water vapor in the waste gas, reducing the possibility that more water vapor floats out of the air outlet hood and mixes with the combustible mixture, affecting the combustion of the combustible mixture in the combustion chamber.

[0019] Optionally, an activated carbon net is installed at the air outlet end of the air outlet hood.

[0020] By adopting the above technical solution, the activated carbon net is used to adsorb the water vapor and toxic substances in the waste gas, reducing the components of water vapor and toxic substances in the waste gas.

[0021] Optionally, the water outlet end of the water inlet pipe communicates with the lowest position on the inner wall of the housing, a plurality of spiral arc plates are connected to the inner wall of the housing, mounting holes are formed on the spiral arc plates, and the cooling pipe is arranged in the mounting holes.

[0022] By adopting the above technical solution, in order to save costs, the coolant in the cooler is usually used for a long time. However, scale will also be generated when the coolant is heated (the amount of scale generated by the coolant is much less than that generated by water). The higher the temperature, the faster the scale is generated. Therefore, scale is extremely likely to form on the surface of the cooling pipe. After the cooler is used for a long time, the scale covering the cooling pipe will affect the heat exchange of the exhaust gas and reduce the cooling effect of the cooler. The staff connects the water outlet end of the water inlet pipe to the lowest part of the inner wall of the housing. In this way, when injecting the coolant, due to inertia, the coolant will flow along the circumferential direction of the inner wall of the housing, and then under the guidance of the spiral arc plate, the coolant will flow along the direction of the spiral arc plate to form a spiral water flow, so as to wash the surface of the cooling pipe and increase the flow rate of the coolant. The cooperation of the two delays the time for the scale to adhere to the surface of the cooling pipe, reduces the cleaning times of the cooler, and improves the cooling efficiency of the cooler. The spiral arc plate is also used to support the cooling pipe, reducing the possibility that the middle position of the cooling pipe is deformed due to the influence of thermal expansion and contraction, resulting in the retention of liquefied exhaust gas in the cooling pipe.

[0023] In summary, the present application includes at least one of the following beneficial technical effects:

[0024] 1. When it is necessary to heat the coolant, the staff uses the controller to energize the first heating wire, so that the first heating wire generates heat and transfers it to the pipe wall of the water inlet pipe. Before the coolant enters the housing from the water inlet pipe, it exchanges heat with the heated water inlet pipe, achieving the effect of heating the coolant. The staff uses the controller to control the temperature of the first heating wire to control the temperature of the coolant. The heated coolant contacts the cooling pipe and exchanges heat with the high-temperature exhaust gas through the cooling pipe, reducing the temperature difference between the coolant and the high-temperature exhaust gas, reducing the possibility of liquefaction of the high-temperature exhaust gas in the cooling pipe, thereby reducing the accumulation of carbon deposits, keeping the cooling pipe unobstructed as much as possible, and improving the cooling effect of the cooler;

[0025] 2. The staff connects the water outlet end of the water inlet pipe to the lowest part of the inner wall of the housing. In this way, when injecting the coolant, due to inertia, the coolant will flow along the circumferential direction of the inner wall of the housing, and then under the guidance of the spiral arc plate, the coolant will flow along the direction of the spiral arc plate to form a spiral water flow, so as to wash the surface of the cooling pipe and increase the flow rate of the coolant. The cooperation of the two delays the time for the scale to adhere to the surface of the cooling pipe, reduces the cleaning times of the cooler, and improves the cooling efficiency of the cooler. The spiral arc plate is also used to support the cooling pipe, reducing the possibility that the middle position of the cooling pipe is deformed due to the influence of thermal expansion and contraction, resulting in the retention of liquefied exhaust gas in the cooling pipe. Description of the Drawings

[0026] Figure 1 is a schematic diagram of the overall structure of an EGR cooler in an embodiment of the present application.

[0027] Figure 2 isFigure 1 Enlarged view of part A

[0028] Figure 3 It is a cross-sectional view used to show the internal structure of the cooler in the embodiment of the present application.

[0029] Figure 4 It is a cross-sectional view used to show the position of the water inlet pipe in the embodiment of the present application.

[0030] Figure 5 It is a cross-sectional view used to show the structure of the air outlet hood in the embodiment of the present application.

[0031] Explanation of reference numerals: 1. Housing; 11. Water inlet pipe; 12. Water outlet; 13. Spiral arc plate; 2. Air inlet hood; 3. Air outlet hood; 31. Activated carbon net; 32. Heat dissipation ring plate; 33. Collection tank; 34. Collection hole; 35. Guide ring; 4. Cooling pipe; 41. Mounting plate; 5. Heating component; 51. First heating wire; 511. Heat preservation cover; 52. Controller; 6. Second heating wire; 7. Collection box; 71. Overflow pipe. Detailed implementation manners

[0032] The following further elaborates on the present application in conjunction with the Figures 1-5 drawings.

[0033] The embodiment of the present application discloses an EGR cooler. Referring to Figure 1 , Figure 2 and Figure 3 , an EGR cooler includes a housing 1, an air inlet hood 2, an air outlet hood 3 and a cooling pipe 4. The housing 1 is arranged as a cylinder, and both ends of the housing 1 are connected with mounting plates 41 by bolts. A plurality of cooling pipes 4 are provided and are all arranged between the two mounting plates 41. The cooling pipes 4 are arranged obliquely. In this embodiment, the inclination angle of the cooling pipes 4 is 1 degree, and the height of the air inlet end of the cooling pipes 4 is higher than that of the air outlet end. The air inlet hood 2 and the air outlet hood 3 are both connected to the housing 1 by flanges.

[0034] Referring to Figure 1 , Figure 3 and Figure 4 , a water inlet pipe 11 and a water outlet 12 are fixedly connected to the surface of the housing 1. The water outlet end of the water inlet pipe 11 communicates with the lowest part of the inner wall of the housing 1, and the water inlet end of the water outlet 12 communicates with the highest part of the inner wall of the housing 1. A plurality of spiral arc plates 13 are fixedly connected to the inner wall of the housing 1. Mounting holes are formed at positions corresponding to the cooling pipes 4 on the spiral arc plates 13, and the cooling pipes 4 are installed in the mounting holes. The cooperation between the water inlet pipe 11 and the spiral arc plates 13 is used to make the coolant form a spiral water flow, increasing the flow rate of the coolant to wash the surface of the cooling pipes 4. The spiral arc plates 13 are also used to assist in supporting the cooling pipes 4.

[0035] Referring to Figure 1 andFigure 2 The water inlet pipe 11 is provided with a heating component 5. The heating component 5 includes a first heating wire 51 and a controller 52. The first heating wire 51 is wound around the surface of the water inlet pipe 11. The operating temperature of the first heating wire 51 is lower than the exhaust gas temperature. In this embodiment, 90 degrees is taken as an example. A heat insulation cover 511 is fixedly connected to the surface of the water inlet pipe 11, and the first heating wire 51 is located inside the heat insulation cover 511. The controller 52 is installed on the surface of the housing 1, and the first heating wire 51 is electrically connected to the controller 52.

[0036] When heating the coolant, the staff uses the controller 52 to energize the first heating wire 51, so that the first heating wire 51 generates heat and transfers it to the pipe wall of the water inlet pipe 11. The coolant exchanges heat with the heated water inlet pipe 11 before entering the housing 1 from the water inlet pipe 11, achieving the effect of heating the coolant.

[0037] Refer to Figure 3 and Figure 4 As shown in FIG. and FIG., a plurality of second heating wires 6 are fixedly connected to the mounting plate 41 near the air outlet hood 3. The second heating wires 6 are electrically connected to the controller 52. The operating temperature of the second heating wires 6 is lower than the exhaust gas temperature. In this embodiment, 90 degrees is taken as an example. The surface of the second heating wires 6 is wrapped with a waterproof pipe. The second heating wires 6 are used to heat the area of the cooling pipe 4 near the air inlet hood 2.

[0038] Refer to Figure 5 As shown in FIG., the air outlet hood 3 is arranged in a frustum shape, and the air inlet end of the air outlet hood 3 is close to the housing 1. An installation groove is opened at the air outlet end of the air outlet hood 3, and an activated carbon net 31 is connected in the installation groove by bolts. The activated carbon net 31 is used to adsorb water vapor and toxic substances in the exhaust gas. A plurality of heat dissipation ring plates 32 are fixedly connected to the surface of the air outlet hood 3, and the heat dissipation ring plates 32 are used to increase the heat dissipation area of the air outlet hood 3. The cooperation between the heat dissipation ring plates 32 and the frustum-shaped air outlet hood 3 is beneficial to the heat exchange of the exhaust gas and the collection of water vapor in the exhaust gas.

[0039] Refer to Figure 5 As shown in FIG., a collection groove 33 is opened on the inner wall of the air outlet hood 3. A collection hole 34 is opened at the lowest part of the collection groove 33. A guiding ring 35 is fixedly connected to the inner wall of the air outlet hood 3. The guiding ring 35 is used to guide the liquefied exhaust gas in the cooling pipe 4 to flow into the collection groove 33. A collection box 7 is fixedly connected to the lowest part of the outer surface of the air outlet hood 3. The collection hole 34 communicates with the collection box 7. An overflow pipe 71 is fixedly connected to the surface of the collection box 7. The overflow pipe 71 is arranged obliquely, and the height of the water outlet end of the overflow pipe 71 is higher than the height of the water inlet end. A gas-blocking liquid is arranged in the collection box 7, and the height of the water inlet end of the overflow pipe 71 is lower than the horizontal plane height of the gas-blocking liquid. The gas-blocking liquid is used to prevent the exhaust gas from leaking from the overflow pipe 71.

[0040] The waste gas liquefied in the cooling pipe 4 flows into the collection tank 33 through the guiding ring 35. The waste gas flowing out of the cooling pipe 4 encounters the inner wall of the air outlet cover 3, causing water vapor to adhere to the bottom wall of the collection tank 33, and finally being drained into the collection box 7 through the collection holes 34. When the level of the air-blocking liquid in the collection box 7 is higher than the water outlet end of the overflow pipe 71, the air-blocking liquid flows out from the overflow pipe 71.

[0041] The implementation principle of an EGR cooler in an embodiment of this application is as follows: When it is necessary to cool high-temperature waste gas, the staff passes the waste gas into the intake hood 2, enabling the waste gas to enter the cooling pipe 4. The waste gas transfers heat to the cooling pipe 4. The first heating wire 51 is energized through the controller 52. Subsequently, the coolant enters the housing 1 through the water inlet pipe 11. During this process, the coolant is heated and rises in temperature, and flows along the direction of the spiral arc plate 13, exchanging heat with the cooling pipe 4. A part of the waste gas after heat exchange starts to liquefy, appears in the form of water droplets, and flows out of the cooling pipe 4 along the direction of the cooling pipe 4 and enters the cooling tank. At the same time, the waste gas with water vapor floats out of the cooling pipe 4 and encounters the inner wall of the air outlet cover 3. A part of the waste gas is liquefied again to lower the temperature, and the liquefied waste gas accumulates more and more on the bottom wall of the collection tank 33, and finally flows into the collection box 7 through the collection holes 34. The toxic substances and residual water vapor in the cooled waste gas are adsorbed by the activated carbon net 31, and then the waste gas flows out of the air outlet cover 3, achieving the effect of cooling the waste gas.

[0042] The staff uses the controller 52 to control the temperature of the first heating wire 51 to control the temperature of the coolant. The heated coolant contacts the cooling pipe 4, and through the heat exchange between the cooling pipe 4 and the high-temperature waste gas, the temperature difference between the coolant and the high-temperature waste gas is reduced, reducing the possibility of the high-temperature waste gas liquefying in the cooling pipe 4, thereby reducing the accumulation of carbon deposits, keeping the cooling pipe 4 unblocked as much as possible, and improving the cooling effect of the cooler.

[0043] The above are all the preferred embodiments of this application, and the protection scope of this application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. An EGR cooler, comprising a housing (1), an intake hood (2), an exhaust hood (3) and cooling tubes (4). Both ends of the housing (1) are connected with mounting plates (41). A plurality of cooling tubes (4) are provided and are all arranged between the two mounting plates (41). The intake hood (2) is connected to one end of the housing (1), and the exhaust hood (3) is connected to the other end of the housing (1). A water inlet pipe (11) and a water outlet (12) are connected to the surface of the housing (1), and it is characterized in that: The water inlet pipe (11) is arranged at a position of the housing (1) close to the air outlet hood (3). A heating assembly (5) is arranged in the water inlet pipe (11). The heating assembly (5) includes a first heating wire (51) and a controller (52). The first heating wire (51) is connected to the outer wall of the water inlet pipe (11). The heating temperature of the first heating wire (51) is lower than the waste gas temperature. A heat preservation cover (511) is arranged on the outer wall of the water inlet pipe (11). The first heating wire (51) is located in the heat preservation cover (511). The controller (52) is connected to the surface of the housing (1). The first heating wire (51) is electrically connected to the controller (52). The cooling pipe (4) is arranged obliquely. The height of one end of the cooling pipe (4) close to the air inlet hood (2) is higher than the height of the other end of the cooling pipe (4) close to the air outlet hood (3). A collection box (7) for collecting waste liquid is connected to the air outlet hood (3). The air outlet hood (3) is arranged in a frustum shape. The diameter of the air outlet end of the air outlet hood (3) is smaller than the diameter of the air inlet end. A collection groove (33) is formed on the inner wall of the air outlet hood (3). A guiding ring (35) is connected to the inner wall of the air outlet hood (3). The guiding ring (35) is used for guiding the waste liquid in the cooling pipe (4) to flow into the collection groove (33). A collection hole (34) is formed at the lowest position of the collection groove (33). The collection hole (34) communicates with the collection box (7). The collection box (7) is connected to the lowest position of the surface of the air outlet hood (3). An overflow pipe (71) is connected to the collection box (7). The overflow pipe (71) is arranged obliquely. A gas-blocking liquid is arranged in the collection box (7). The height of the water inlet end of the overflow pipe (71) is lower than the height of the water outlet end of the overflow pipe (71), and the water inlet end of the overflow pipe (71) is located in the gas-blocking liquid.

2. An EGR cooler according to claim 1, characterized in that: A second heating wire (6) is connected to the mounting plate (41) close to the air outlet hood (3). A waterproof pipe is wrapped on the surface of the second heating wire (6). The second heating wire (6) is electrically connected to the controller (52). The working temperature of the second heating wire (6) is lower than the waste gas temperature.

3. An EGR cooler according to claim 1, characterized in that: A plurality of heat dissipation ring plates (32) are connected to the surface of the air outlet hood (3).

4. An EGR cooler according to claim 3, characterized in that: An activated carbon net (31) is installed at the air outlet end of the air outlet hood (3).

5. An EGR cooler according to claim 4, characterized in that: The water outlet end of the water inlet pipe (11) communicates with the lowest position of the inner wall of the housing (1). A plurality of spiral arc plates (13) are connected to the inner wall of the housing (1). Mounting holes are formed in the spiral arc plates (13). The cooling pipe (4) is arranged through the mounting holes.

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