JP2005069064A - EGR cooler - Google Patents

Abstract

Cooling water stagnation is prevented without restricting the mounting posture of an EGR cooler on a vehicle.
SOLUTION: A tube 3, a shell 1 surrounding the tube 3, and a core plate 2 provided at both ends of the shell 1 and having both ends of the tube 3 penetrated and fixed, and cooling water 9 is provided inside the shell 1. An EGR cooler that supplies and discharges the exhaust gas 10 through the tube 3 and exchanges heat between the exhaust gas 10 and the cooling water 9. An annular cooling water supply chamber 11 is provided near one end in the axial direction of the shell 1. The cooling water inlet pipe 4 is connected to an appropriate position in the circumferential direction of the cooling water supply chamber 11, and the inside of the cooling water supply chamber 11 and the shell 1 are connected to the shell 1 in the cooling water supply chamber 11. A communication hole 12 is formed by an annular slit that communicates with the inside.
[Selection] Figure 1

Description

  The present invention relates to an EGR cooler attached to an EGR device that recirculates engine exhaust gas to reduce generation of nitrogen oxides and cools the recirculation exhaust gas.

  Conventionally, an EGR device that reduces the generation of nitrogen oxides by recirculating a part of exhaust gas of an engine such as an automobile to the engine is known. In such an EGR device, the exhaust gas recirculated to the engine is known. When the engine is cooled, the temperature of the exhaust gas is lowered and the volume of the exhaust gas is reduced, so that the combustion temperature can be lowered and the generation of nitrogen oxides can be effectively reduced without significantly reducing the engine output. Some engines are equipped with an EGR cooler for cooling the exhaust gas in the middle of the line for recirculating the exhaust gas to the engine.

  FIG. 7 is a cross-sectional view showing an example of the EGR cooler. In FIG. 7, reference numeral 1 denotes a shell formed in a cylindrical shape, and a core plate that closes the end face of the shell 1 at both ends in the axial direction of the shell 1. 2 and 2 are fixed, and both ends of a large number of tubes 3 are fixed to the respective core plates 2 and 2 in a penetrating manner. The large numbers of tubes 3 extend in the axial direction inside the shell 1. Yes.

  A cooling water inlet pipe 4 is attached in the vicinity of one end of the shell 1, a cooling water outlet pipe 5 is attached in the vicinity of the other end of the shell 1, and the cooling water 9 is supplied to the cooling water inlet pipe. 4 is supplied to the inside of the shell 1, flows outside the tube 3, and is discharged from the cooling water outlet pipe 5 to the outside of the shell 1.

  Further, bonnets 6, 6 formed in a bowl shape are fixed to the opposite side of the shells 1 of the core plates 2, 2 so as to enclose the end faces of the core plates 2, 2. An exhaust gas inlet 7 is provided at the center, and an exhaust gas outlet 8 is provided at the center of the other bonnet 6, and engine exhaust gas 10 enters the inside of one bonnet 6 from the exhaust gas inlet 7. After being cooled by heat exchange with the cooling water 9 flowing outside the tube 3 while passing through the tube 3, it is discharged into the other bonnet 6 and recirculated to the engine from the exhaust gas outlet 8. Yes.

  In such a conventional EGR cooler, after flowing into the inside of the shell 1 from the cooling water inlet pipe 4, it is easy to form an obliquely flowing flow at the shortest distance with respect to the cooling water outlet pipe 5. If only the cooling water outlet pipe 5 is provided, stagnation of the cooling water 9 is formed in the vicinity of the corner of the shell 1 facing the cooling water inlet pipe 4. A bypass outlet pipe 5a is provided at a facing position, and a portion of the cooling water 9 is extracted from the bypass outlet pipe 5a to prevent the cooling water 9 from stagnation. The risk of thermal deformation is avoided in advance.

As prior art document information related to the same EGR cooler, the following patent documents 1 and 2 have already been filed by the same applicant as the present invention.
JP 2002-327654 A JP 2000-45884 A

  However, the conventional bypass outlet pipe 5a also serves as an air vent for discharging the air mixed in the shell 1, so that both of them are vertically arranged so that the cooling water inlet pipe 4 is down and the bypass outlet pipe 5a is up. There is a problem that the mounting posture of the EGR cooler on the vehicle is restricted, because it must be disposed opposite to each other in the direction.

  The present invention has been made in view of the above circumstances, and prevents the problem of stagnation of cooling water without restricting the mounting posture of the EGR cooler on the vehicle, and the prevention of this problem with a simple configuration. The goal is to achieve.

  The invention according to claim 1 includes a tube, a shell surrounding the tube, and a core plate provided at both ends of the shell and having both ends of the tube penetrated and fixed, and cooling water is provided inside the shell. An EGR cooler that supplies and discharges heat and exchanges heat between the exhaust gas and the cooling water through the inside of the tube, and an annular cooling water supply chamber is fitted around one end in the axial direction of the shell. A cooling water inlet pipe is connected to an appropriate position in the circumferential direction of the cooling water supply chamber, and the shell in the cooling water supply chamber communicates with the inside of the cooling water supply chamber and the inside of the shell. The present invention relates to an EGR cooler characterized in that a communication port is formed by a slit.

  According to a second aspect of the present invention, the communication port is a tapered communication port in which the slit width decreases as the distance from the connection portion of the cooling water inlet tube in the circumferential direction decreases, and cooling water is supplied from the cooling water inlet tube. 2. The EGR cooler according to claim 1, wherein the cooling water supplied into the chamber is introduced into the shell substantially uniformly in the circumferential direction.

  According to a third aspect of the present invention, the communication port is provided at a position offset in the axial direction of the shell in the cooling water supply chamber, and the cooling water supplied from the cooling water inlet pipe to the inside of the cooling water supply chamber is the shell. 3. The EGR cooler according to claim 1, wherein the EGR cooler is introduced into the shell through the communication port after colliding with the overhanging portion.

  According to a fourth aspect of the present invention, the leg plate of the cooling water supply chamber is fixed to the shell and the core plate, respectively, and the communication port is provided between the inner surface of the core plate side leg plate of the cooling water supply chamber and the end surface of the shell. The EGR cooler according to any one of claims 1 to 3, wherein the EGR cooler is formed.

  Thus, in the configuration described above, the cooling water introduced into the cooling water supply chamber from the cooling water inlet pipe flows in the circumferential direction inside the cooling water supply chamber and is distributed and introduced into the shell from the communication port formed by the annular slit. Therefore, the problem that the cooling water stagnates inside the shell is prevented.

  In addition, according to the tapered communication port whose slit width decreases as the distance from the connection point of the cooling water inlet pipe decreases in the circumferential direction, the cooling water supplied from the cooling water inlet pipe to the inside of the cooling water supply chamber is substantially omitted in the circumferential direction. It will be evenly introduced inside the shell.

  According to the communication port provided at a position offset in the axial direction of the shell in the cooling water supply chamber, the cooling water supplied from the cooling water inlet pipe to the cooling water supply chamber collides with the shell, and thereby along the outer surface of the shell. It becomes easy to flow in the circumferential direction.

  According to the EGR cooler of the present invention described above, since the communication port by the annular slit is provided, the cooling water introduced into the cooling water supply chamber can be dispersedly introduced into the shell from the circumferential direction. Since the problem of the formation of starch inside can be prevented, the heat exchange efficiency between the exhaust gas and the cooling water can be greatly improved and the heat deformation due to the local high temperature of the tube can be surely prevented. . Further, the uppermost part of the communication port by the annular slit serves as an air vent for exhausting air from the inside of the shell. Therefore, the EGR cooler is rotated around the axis of the shell, so that the cooling water inlet pipe Can be freely changed, and restrictions on the mounting posture of the EGR cooler on the vehicle can be greatly relaxed compared to the conventional case.

  In addition, the communication port formed by the annular slit is a tapered communication port whose slit width decreases as the distance from the connection point of the cooling water inlet pipe decreases in the circumferential direction, so that the cooling water inlet pipe supplies the cooling water to the inside of the cooling water supply chamber. The cooling water is introduced into the shell substantially evenly in the circumferential direction, so that the heat exchange efficiency between the exhaust gas and the cooling water is further improved, and the heat deformation due to the local high temperature of the tube is further ensured. Can be prevented.

  By providing the communication port of the annular slit so as to be offset in the axial direction of the shell inside the cooling water supply chamber, the cooling water supplied from the cooling water inlet pipe to the inside of the cooling water supply chamber is introduced into the projecting portion of the shell. Since it collides and flows in the circumferential direction along the outer peripheral surface, the cooling water introduced from the communication port into the shell is further made uniform in the circumferential direction.

  Further, since the communication port by the annular slit can be formed by cutting the shell, the manufacture of the EGR cooler is facilitated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 to 3 show an example of an embodiment of the present invention. FIG. 1 is a cross-sectional view of an EGR cooler, FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1, and FIG. FIG. 8 is an enlarged cross-sectional view of a portion, and the same reference numerals are given to the same portions as those in FIG.

  As shown in FIGS. 1 to 3, in the EGR cooler of this embodiment, an annular cooling water supply chamber 11 is externally fitted near one end in the axial direction of the shell 1 (near the left end in FIG. 1), and the cooling water The cooling water inlet pipe 4 is connected to an appropriate position in the circumferential direction of the supply chamber 11 (the lowermost part in the drawing).

  A communication port 12 is formed in the shell 1 in the cooling water supply chamber 11 by an annular slit that communicates the inside of the cooling water supply chamber 11 and the inside of the shell 1.

  In the example shown in FIG. 1, an annular cooling water discharge chamber 14 is also fitted to the vicinity of the other end in the axial direction of the shell 1 (near the right end in FIG. 1). A cooling water outlet pipe 5 is connected to an appropriate position in the circumferential direction (the uppermost part in the drawing), and the inside of the cooling water discharge chamber 14 and the inside of the shell 1 are communicated with the shell 1 in the cooling water discharge chamber 14. Although the communication port 15 is formed by the annular slit, only the cooling water outlet pipe 5 may be disposed without providing the cooling water supply chamber 11 as in the conventional case. That is, on the discharge side of the cooling water 9, the main heat exchange has already been completed and the temperature difference between the exhaust gas 10 and the cooling water 9 is small, and the locality of the tube 3 due to the stagnation of the cooling water 9 is reduced. This is because the formation of stagnation of the cooling water 9 is not considered as a problem because there is no concern about high temperatures. However, in order to discharge the air inside the shell 1 regardless of the direction of the cooling water outlet pipe 5, a cooling water discharge chamber 14 is also provided in the cooling water outlet pipe 5 and a communication port 15 by an annular slit is provided in the shell 1. Is preferred.

  The cooling water supply chamber 11 shown in FIG. 3 forms a substantially U-shaped annular shape with inner sides opened by the left and right leg plates 16, 17 and the outer peripheral plate 18. An inlet pipe 4 is attached. In this configuration, the short shell 19 is formed by cutting the vicinity of the end portion of the shell 1 fixed to the core plate 2 at a required interval S, and the short shell 19 is fixed to the core plate 2, thereby An annular communication port 12 having a slit width of S is formed between the shell 19 and the end face 1 a of the shell 1. The leg plates 16 and 17 of the cooling water supply chamber 11 are fitted and fixed to the outer peripheral surface of the short shell 19 and the outer peripheral surface of the shell 1.

  At this time, the communication port 12 is placed in the cooling water supply chamber 11 so that the end surface on the communication port 12 side of the short shell 19 and the inner surface 16a of the leg plate 16 on the core plate 2 side of the cooling water supply chamber 11 are in the same position. The protruding portion 13 is formed in the cooling water supply chamber 11 so that the end surface 1a of the shell 1 protrudes.

  FIG. 4 shows another example of the embodiment shown in FIG. 3. Without providing the short shell 19, one leg plate 16 of the cooling water supply chamber 11 is directly fixed to the core plate 2, and the other leg plate 17. Is fixed to the outer peripheral surface of the shell 1, so that one leg plate 16 is longer in length than the other leg plate 17, and the inner surface of the one leg plate 16 and the inner surface of the shell 1 are the same. I'm doing it. The communication port 12 formed by the annular slit is formed between the inner surface 16 a on the core plate 2 side of the cooling water supply chamber 11 and the end surface 1 a of the overhanging portion 13 of the shell 1.

  1 to 4, the cooling water 9 supplied from the cooling water inlet pipe 4 to the inside of the cooling water supply chamber 11 flows in the cooling water supply chamber 11 in the circumferential direction and is formed by the annular slit. Since it is introduced into the inside of the shell 1 through the communication port 12, it is possible to prevent stagnation inside the shell 1. Therefore, the heat exchange efficiency between the exhaust gas 10 and the cooling water 9 is greatly improved, and thermal deformation due to local high temperature of the tube 3 is reliably prevented.

  Even if the EGR cooler is not mounted on the vehicle in such a posture that the cooling water inlet pipe 4 faces downward, the uppermost portion of the communication port 12 by the annular slit provided in the shell 1 Since it serves as an air vent for discharging, the orientation of the cooling water inlet pipe 4 can be freely changed by rotating the attitude of the EGR cooler around the axis of the shell 1.

  Further, the communication port 12 formed by the annular slit is disposed in the cooling water supply chamber 11 so as to be offset toward the core plate 2 side, and the projecting portion 13 of the shell 1 is formed in the cooling water supply chamber 11. Since the cooling water 9 supplied to the inside of the cooling water supply chamber 11 collides with the overhanging portion 13 of the shell 1 and flows in the circumferential direction along the outer surface of the overhanging portion 13, the cooling water 9 It is distributed in the direction and introduced into the shell 1 from the communication port 12 by the annular slit.

  Further, by providing the communication port 12 so as to be offset toward the core plate 2 in the cooling water supply chamber 11, the cooling water 9 is supplied from the communication port 12 to the vicinity of the end of the tube 3 close to the core plate 2. Therefore, the heat exchange efficiency of the tube 3 is increased.

  FIGS. 5 and 6 show other forms of the communication port 12 by the annular slit shown in FIGS. 3 and 4. In FIGS. 5 and 6, the cooling water inlet pipe 4 is connected. A tapered communication port 12 is formed in which the interval S (slit width) decreases as the interval S ′ increases away from the location in the circumferential direction. 5 and 6, a tapered communication port 12 'is formed by making the end surface of the overhanging portion 13 of the shell 1 into an inclined surface 1b. Therefore, in this case, the tapered communication port 12 'can be formed by cutting the end portion of the shell 1 so as to be the inclined surface 1b.

  As shown in FIGS. 5 and 6, when the tapered communication port 12 ′ having a slit width that decreases in the circumferential direction from the connection portion of the cooling water inlet pipe 4 is formed, the cooling water supply chamber is formed from the cooling water inlet pipe 4. The cooling water 9 supplied to the inside of the gas generator 11 is distributed substantially evenly in the circumferential direction and introduced into the shell 1, so that the heat exchange efficiency between the exhaust gas 10 and the cooling water 9 is further improved. In addition, thermal deformation due to local high temperature of the tube 3 can be prevented more reliably.

  Note that the EGR cooler of the present invention is not limited to the above-described embodiments, and various changes can be made without departing from the scope of the present invention.

An example of the embodiment of the present invention is shown, and is a cross-sectional view of an EGR cooler. It is sectional drawing of the II-II arrow of FIG. It is an expanded sectional view of the III part of FIG. It is sectional drawing which shows the other example of the form of FIG. It is sectional drawing which shows the form which made the communicating port in the structure of FIG. 3 the taper-shaped communicating port. It is sectional drawing which shows the form which made the communicating port in the structure of FIG. 4 the taper-shaped communicating port. It is sectional drawing which shows an example of the conventional EGR cooler.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shell 1a End surface 2 Core plate 3 Tube 4 Cooling water inlet pipe 9 Cooling water 10 Exhaust gas 11 Cooling water supply chamber 12 Communication port 12 'Tapered communication port 13 Overhanging portion 14 Cooling water discharge chamber 15 Communication port 16a Inner surface S interval ( Slit width)
S 'interval (slit width)

Claims (4)

  A tube, a shell that surrounds the tube, and a core plate that is provided at both ends of the shell and through which both ends of the tube are fixed. The cooling water is supplied to and discharged from the shell and the tube An EGR cooler configured to exchange heat between the exhaust gas and the cooling water through the exhaust gas, wherein an annular cooling water supply chamber is externally fitted near one end in the axial direction of the shell, and the cooling water supply chamber A cooling water inlet pipe is connected to an appropriate position in the circumferential direction of the above, and a communication port is formed in the shell in the cooling water supply chamber by an annular slit that connects the inside of the cooling water supply chamber and the inside of the shell. A featured EGR cooler.   Cooling water supplied from the cooling water inlet pipe to the inside of the cooling water supply chamber is formed as a tapered communication opening in which the slit width decreases as it goes away from the connection location of the cooling water inlet pipe in the circumferential direction. The EGR cooler according to claim 1, wherein the EGR cooler is introduced into the shell substantially uniformly in the circumferential direction.   The communication port is provided at a position offset in the axial direction of the shell in the cooling water supply chamber, and the communication port after the cooling water supplied from the cooling water inlet pipe to the inside of the cooling water supply chamber collides with the protruding portion of the shell. The EGR cooler according to claim 1, wherein the EGR cooler is introduced into the shell from the inside.   The cooling water supply chamber leg plate is fixed to the shell and the core plate, respectively, and the communication port is formed between the inner surface of the cooling water supply chamber core plate side leg plate and the end surface of the shell. Item 4. The EGR cooler according to any one of Items 1 to 3.

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