JP2007046890A - Tubular heat exchanger for egr gas cooler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tubular heat exchanger providing excellent heat exchange efficiency, by introducing EGR gas into a plurality of heat transfer tubes arranged in the tubular heat exchanger for an EGR (Exhaust Gas Recirculation) gas cooler, at a uniform flow rate with a uniform flow velocity distribution. <P>SOLUTION: In this tubular heat exchanger for the EGR gas cooler, a bonnet connected integrally to an EGR gas inlet side of a shell main body constituting the tubular heat exchanger via a tube sheet to bring a cross-sectional shape into a substantially rectangular shape along an axial center of the shell main body, in the shell and tube type tubular heat exchanger in the EGR gas cooler, an EGR gas flow-in tube is provided along a radial direction of an outer circumferential face thereof, and a guide plate is provided on a wall face opposed to the tube sheet in the bonnet, with a prescribed distance from a flow-in port of the EGR gas flow-in tube. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a so-called shell and tube type multi-tube heat exchanger for an EGR gas cooling device, and more specifically, is connected to the EGR gas inflow pipe side of the multi-tube heat exchanger in the heat exchange type EGR gas cooling device, It is possible to introduce the EGR gas with a uniform flow velocity distribution by applying a specific improvement to a bonnet that introduces a high-temperature EGR gas that is a medium to be cooled to the EGR gas cooling device. The present invention relates to a multi-tubular heat exchanger for an EGR gas cooling device that efficiently promotes heat exchange.

  A method of taking a part of the exhaust gas from the exhaust system of the diesel engine, returning it to the intake system of the engine again, and adding it to the air-fuel mixture is called EGR (Exhaust Gas Recirculation), which is the NOx (nitrogen oxide) Many effects such as suppression of generation, reduction of pump loss, reduction of heat dissipation loss to coolant due to lowering of combustion gas temperature, increase of specific heat ratio due to change of working gas amount and composition, and improvement of cycle efficiency associated with it Therefore, it is widely adopted as an effective method for purifying exhaust gas from diesel engines and improving thermal efficiency.

  However, if the temperature of the EGR gas rises and the amount of EGR gas increases, the durability of the EGR valve deteriorates due to its thermal action, and there is a risk of early breakage. There is a need for a structure, and as the intake air temperature rises, the charging efficiency is lowered and the fuel consumption is lowered. In order to avoid such a situation, a device for cooling EGR gas with engine coolant, car air-conditioner refrigerant or cooling air is used, and in particular, gas-liquid that cools EGR gas, which is a gas, with engine coolant. Many heat exchange type EGR gas cooling devices have been proposed and used. Among these gas-liquid heat exchange type EGR gas cooling devices, there is still a strong demand for double-tube heat exchange type EGR gas cooling devices that have a simple structure and can be easily installed even in narrow installation spaces. For example, in an exchanger that arranges an outer tube through which liquid passes outside the inner tube through which high-temperature EGR gas passes and performs heat exchange between the gas and the liquid, a metal corrugated plate is inserted as a fin in the inner tube 2 A double-pipe heat exchanger (see, for example, Patent Document 1), an inner pipe through which a medium to be cooled is circulated, an outer pipe provided so as to surround and surround the outer circumference of the inner pipe, and the inner pipe A number of double-pipe heat exchangers have been proposed, including a double-pipe heat exchanger (see, for example, Patent Document 2) that is composed of heat dissipating fins having a thermal stress relaxation function disposed inside. ing.

  According to the double-pipe heat exchanger having the fin structure with various improvements as described above, although its structure is simple and compact, excellent cooling efficiency can be expected. Therefore, many heat exchangers for cooling EGR gas, such as small cars, that have limited installation space, have already been put to practical use, but the absolute amount of fluid that flows is naturally limited because of its compact structure. As a result, unsolved problems remain in the total heat exchange efficiency. In order to solve such problems, even if the structure is somewhat complicated and the size must be increased, so-called shell-and-tube type multi-tubular heat exchangers must be adopted, and various types of these heat exchangers can be used. Improvements have been made. As an example of a shell-and-tube type multi-tube heat exchanger, a nozzle serving as a cooling water inlet and a cooling water outlet at one end of the outer peripheral portion of the shell main body constituting the cooling jacket are respectively attached to the shell. A bonnet for introducing high-temperature EGR gas is integrally provided at one end in the longitudinal direction of the main body, and a heat-exchanged EGR gas discharging bonnet is integrally provided at the other end via tube sheets attached to the inside of each bonnet. A plurality of flat heat transfer tubes are attached at intervals, and hot EGR gas flows through the flat heat transfer tubes so as to intersect with the cooling water flowing through the shell body, and In addition to the wide heat transfer area formed by the flat heat transfer tube, a U-shaped plate fin is installed on the inner peripheral surface of the flat heat transfer tube to narrow the EGR gas flow that flows. That at the same time, the aim of further increase in the heat transfer area, a multi-tube heat exchanger to obtain excellent heat exchange efficiency (e.g., see Patent Document 3) are disclosed.

On the other hand, in the shell-and-tube type multi-tube heat exchanger, a large number of the heat transfer tubes arranged in the shell at intervals are formed to form a heat transfer tube group with a uniform flow distribution and flow velocity. The passage of EGR gas as a medium to be cooled is a major requirement for improving the heat exchange efficiency. According to the EGR gas cooling device shown in FIG. 16 (a), the shell body constituting the cooling jacket As shown in FIG. 2B, the heat transfer tube 20 disposed in the portion 10 is close to the axial center, that is, the portion where the EGR gas flows easily, a heat transfer tube 20a having a small diameter is disposed, and the flow of the EGR gas An EGR gas cooling device (see, for example, Patent Document 4) is proposed in which a heat transfer tube 20 having a large tube diameter is disposed in each of the difficult outer portions so as to balance the flow rate and the flow velocity. According to another conventional example shown in FIG. According to the EGR gas cooling device 100 including a multi-tube heat exchanger, the entire length L1 of the bonnet 170-1 connected to the EGR gas inlet 150 side via the tube sheet 160-1 is connected to the EGR gas outlet side. By making the length more than about twice as long as that of the bonnet 170-2, the flow of the EGR gas flowing into the bonnet 170-1 is given a run-up opportunity of a predetermined distance such as collision / diffusion and the like. There has been proposed an EGR gas cooling device (see, for example, Patent Document 5) in which the cooling efficiency is improved by preventing the bias.
Japanese Patent Laid-Open No. 11-23181 (pages 1-6, FIGS. 1-2) JP 2000-1111277 A (pages 1 to 12, FIGS. 1 to 12) JP 2002-107091 A (pages 1 to 4, FIGS. 1 to 6) Japanese Patent Application Laid-Open No. 11-193992 (pages 1 to 4, FIGS. 1 to 6) Japanese Patent Laid-Open No. 11-280563 (pages 1 to 9, FIGS. 1 to 10)

  In each of the above prior arts, in the case of the EGR gas cooling device of the double pipe type disclosed in Patent Documents 1 and 2, the structure is simple and compact as described above, but it is excellent as such. Since cooling efficiency can be expected, many heat exchangers for EGR gas cooling that have limited installation space, such as small automobiles, have already been put to practical use. The absolute amount is naturally limited, and as a result, unsolved problems remain in the total heat exchange efficiency. According to the EGR gas cooling device of Patent Document 3 as a shell-and-tube type multi-tube heat exchanger for solving such a problem, a heat transfer tube disposed in the shell body has a wider heat transfer area. It has been reported that the flat heat transfer tube is equipped with a U-shaped fin structure in the flat heat transfer tube and exhibits excellent heat exchange performance. However, EGR gas introduced into the shell body is reported. No special consideration has been given to equalizing the flow velocity and flow rate, and in the EGR gas cooling device disclosed in Patent Document 4, the diameter of the heat transfer tube disposed in the shell body is the center of the shaft. By making the peripheral part thinner and thicker the part away from it, the flow rate and flow rate distribution of the EGR gas are made uniform, and the expected results have been achieved. Need to be prepared, mounting Since the tube diameter and density of the heat transfer tubes to be produced are not uniform, the processing of the tube sheet is complicated, and it is difficult to secure the direction during assembly. In addition, the bonnet including the EGR gas inflow tube and the shaft of the shell body Various problems remain in the design and processing steps, such as a limitation in layout performance due to the length of the direction being long. Furthermore, in the EGR gas cooling device of Patent Document 5, it is an essential requirement that the hood on the EGR gas inflow side be significantly longer, but the EGR gas cooling device arranged in a limited space is more compact. From what is desired, there remains an unsolved problem that further improvement in layout is desired.

  In each of the above conventional examples, the bonnet for introducing high-temperature EGR gas is integrally connected to the shell main body via the tube sheet, but the EGR gas introduced into the shell main body via the bonnet As long as there is no change in the conditions, the flow velocity and flow rate distribution have the habit of continuing without being corrected according to the inertia once generated. The present invention pays attention to such inertia of the fluid, and by providing a specific guide plate in the connection portion between the inflow pipe of the EGR gas pipe and the bonnet, specifically, in the vicinity of the EGR gas inlet, the inflow into the bonnet. It is intended to promote the diffusion and distribution of EGR gas. That is, the present invention is intended to solve the above-mentioned problems, and by adding an improvement to the hood on the EGR gas inflow side, the EGR gas cooling device is provided with EGR gas despite its simple structure. The present invention provides a multi-tube heat exchanger for an EGR gas cooling device that can be distributed and introduced evenly.

  The multi-tube heat exchanger for an EGR gas cooling device according to the present invention for solving the above-mentioned problems is a shell-and-tube type multi-tube heat exchanger in the EGR gas cooling device and constitutes the multi-tube heat exchanger. A bonnet that is integrally connected to the EGR gas inlet side of the shell main body via a tube sheet is formed in a substantially rectangular cross-sectional shape along the axis of the shell main body, and the EGR gas inflow pipe is connected to the outer peripheral surface of the shell main body. A characteristic component is that a guide plate is provided on the wall surface of the bonnet facing the tube sheet so as to be a predetermined distance from the inlet of the EGR gas inlet pipe. A gist of a multi-tube heat exchanger for an EGR gas cooling device is provided.

  In the multi-tube heat exchanger for an EGR gas cooling device according to the present invention, the cross-sectional shape along the axis of the shell body of the bonnet is substantially semicircular, substantially trapezoidal, or partially inclined or curved. Thus, it is characterized by being formed.

  Furthermore, in the multi-tube heat exchanger for an EGR gas cooling device according to the present invention, the cross-sectional shape of the bonnet has a rectangular shape, a substantially rectangular shape, a substantially elliptical shape or a partial shape corresponding to the cross-sectional shape of the shell body. It is a shape having an inclined surface or a curved surface.

  The multi-tube heat exchanger for an EGR gas cooling device according to the present invention is also configured such that the guide plate is concentric and parallel to the axis of the EGR gas inflow pipe and is corrugated with respect to the flow of the EGR gas that is introduced. It is formed in this.

  In the multi-tube heat exchanger for an EGR gas cooling device according to the present invention, the guide plate is further formed in a substantially V shape having a top portion thereof on an extension line of the axis of the EGR gas inflow pipe. It is what.

  In the multi-tube heat exchanger for an EGR gas cooling device according to the present invention, the guide plate is a flat plate perpendicular to the axis of the EGR gas inflow tube.

  In the multi-tube heat exchanger for an EGR gas cooling device according to the present invention, the guide plate is a flat plate provided concentrically and perpendicularly to the axis of the EGR gas inflow pipe. It is what.

Furthermore, in the multi-tube heat exchanger for an EGR gas cooling device according to the present invention,
The guide plate is formed in an arcuate curved surface that is concentric and perpendicular to the axis of the EGR gas inflow pipe.

  In the multi-tube heat exchanger for an EGR gas cooling device according to the present invention, the guide plate is disposed to be inclined with respect to the axis of the EGR gas inflow pipe.

  In the multi-tube heat exchanger for an EGR gas cooling device according to the present invention, a gap is provided at a predetermined interval between the guide plate and the inner peripheral surface of the bonnet in the vicinity of the EGR gas inlet. Is.

    Furthermore, in the multi-tube heat exchanger for an EGR gas cooling device according to the present invention, at least one or more through holes or slits are formed in the guide plate.

  In the multi-tube heat exchanger for an EGR gas cooling device according to the present invention, the guide plate is made of a metal plate material, and the joining means to the inner wall surface of the bonnet includes welding, brazing, sticking, and other joining methods. It is preferably selected from the above, and is preferably joined integrally.

  In the multi-tube heat exchanger for an EGR gas cooling device according to the present invention, the metal plate material forming the guide plate is made of austenitic stainless steel such as SUS304, SUS304L, SUS316, SUS316L, and the plate thickness is 0. The preferred embodiment is 2 to 0.5 mm.

  According to the shell-and-tube type multi-tube heat exchanger for the EGR gas cooling device according to the present invention, the EGR gas inlet side of the shell body constituting the multi-tube heat exchanger is integrated with the tube sheet via the tube sheet. The bonnet connected as a cross-sectional shape along the axial center of the shell body is formed in a substantially rectangular, substantially semicircular, substantially trapezoidal shape or partially inclined or curved surface, and a cross-section of the transverse cross section The shape is formed in a rectangular shape, a substantially rectangular shape, a substantially elliptical shape, or a shape having a partially inclined surface or a curved surface corresponding to the cross-sectional shape of the cross section of the shell body, and the EGR gas inlet pipe is formed on the outer peripheral surface of the bonnet. A guide plate is provided in a radial direction and on a wall surface facing the tube sheet in the bonnet so as to be a predetermined distance from the inlet of the EGR gas inflow pipe. By having such a structure, the flow of high-temperature EGR gas that has flowed into the inlet through the EGR gas inlet pipe is rectified, and the tube body of the shell body has a constant amount. The flow of the EGR gas that has been introduced into the plurality of heat transfer tubes arranged at intervals is introduced so as to be evenly distributed. As a result, the flow rate and flow velocity distribution of the high-temperature EGR gas flowing through the heat transfer tube can be made uniform, and heat can be exchanged efficiently and evenly in all the heat transfer tubes. A fluid such as EGR gas has a property of flowing in a direction with less pressure loss from the beginning, and once the flow path is determined, it flows down in the same direction due to its inertia unless the condition is changed. If there is a part where an excessive amount of gas flows relative to the design value, the gas temperature is not cooled to a predetermined temperature range, but is discharged outside the system, and conversely, a high temperature EGR gas is small. Although sufficient cooling proceeds at the part where only the flow occurs, the amount of exchange heat is greatly reduced because the fluid flow rate is less than the design value. Therefore, even in the conventional EGR gas cooling device, in the bonnet before being introduced into the shell body, various contrivances have been made to the shape of the bonnet itself in order to evenly rectify the distribution of the fluid. In addition to various improvements as described above, the EGR gas introduced through the EGR gas pipe is rectified at the inlet provided in the radial direction of the outer peripheral surface of the bonnet. Therefore, a structural feature is that a guide plate is provided at a predetermined distance from the inflow port.

  In another embodiment of the present invention, the guide plate may be formed in a corrugated shape that is concentric with the axis of the EGR gas inlet pipe and parallel to the flow of the flowing gas, The top has a substantially V shape with the EGR gas inflow pipe extending along the axis of the EGR gas inflow pipe, the guide plate is a flat plate perpendicular to the axis of the EGR gas inflow pipe, or the flat plate is formed into an arcuate curved surface. The guide plate is inclined with respect to the axis of the EGR gas inflow pipe, a gap is provided at a predetermined interval between the guide plate and the inner peripheral surface of the bonnet, On the other hand, it is desirable to form at least one or more through holes and / or slits. With such a configuration, the EGR gas flowing into the bonnet is effectively diffused and divided, and as a result, introduced into the EGR gas cooling device. EGR gas However, since it is distributed evenly and introduced into the cooling device main body with a uniform flow velocity distribution maintained, it is possible to maximize the heat exchange performance of the EGR gas cooling device and obtain excellent cooling efficiency. it can. The guide plate according to the present invention can be manufactured by a very simple process, and although the means for attaching it to the bonnet is easy, the obtained effect is remarkably excellent. The multi-tube heat exchanger can be expected to make a great contribution from the viewpoint of energy saving, such as being able to reduce the size and weight of the EGR gas cooling device at low cost.

    Hereinafter, embodiments of the present invention will be described in more detail and specifically based on the accompanying drawings and examples, but the present invention is not restricted thereby, and the structure of the bonnet and the shape of the guide plate are not limited. In addition, the design can be freely changed within the scope of the gist of the present invention.

  FIG. 1 is a side view of an essential part schematically showing a shell main body and a bonnet of a multi-tube heat exchanger according to a first embodiment of the present invention, and FIG. 2 is a diagram showing the hood, guide plate, and EGR gas in the same embodiment. FIG. 3 is a cross-sectional view of a main part schematically showing the flow of the EGR gas, FIG. 3 is a cross-sectional view of a main part schematically showing the flow of the bonnet, guide plate, and EGR gas according to the second embodiment of the present invention. FIG. 5 is a cross-sectional view of the main part schematically showing the bonnet, the guide plate, and the flow of EGR gas according to the third embodiment. FIG. 5 shows the bonnet, the guide plate, and the flow of EGR gas according to the fourth embodiment of the present invention. FIG. 6 is a cross-sectional view of an essential part schematically showing a bonnet, a guide plate, and a flow of EGR gas according to another embodiment of the present invention, and FIG. 7 is a cross-sectional view according to the present invention. Further, a bonnet, a guide plate, and a flow of EGR gas according to another embodiment are schematically shown. FIG. 8 is a fragmentary sectional view, FIG. 8 is a fragmentary sectional view schematically showing a bonnet, a guide plate, and a flow of EGR gas according to still another embodiment of the present invention. FIG. 9 is a fifth embodiment according to the present invention. FIG. 10 is a cross-sectional view of a main part schematically showing a bonnet, a guide plate, and a flow of EGR gas. FIG. 10 is a bonnet incorporating a shell main body and a guide plate of a multi-tubular heat exchanger according to a sixth embodiment of the present invention. FIG. 11 is a side view of an essential part schematically showing the flow of EGR gas, FIG. 11 is a shell body of a multitubular heat exchanger according to a seventh embodiment of the present invention, a bonnet incorporating a guide plate, and EGR gas. FIG. 12 is a main part schematically showing a shell body of a multi-tube heat exchanger according to an eighth embodiment of the present invention and a bonnet incorporating a guide plate. FIG. 13 is a side view, and FIG. 13 shows the multitubular heat according to the ninth embodiment of the present invention. FIG. 14 schematically shows the bonnet, the guide plate, and the flow of the EGR gas in the tenth embodiment according to the present invention. FIG. 15 is a fragmentary sectional view schematically showing a bonnet, a guide plate, and a flow of EGR gas in an eleventh embodiment according to the present invention.

  The multi-tube heat exchanger 1 for an EGR gas cooling apparatus according to the first embodiment of the present invention maintains airtightness in the shell body 2 on both sides of the shell body 2 as shown in FIG. A plurality of heat transfer tubes 2-2 are arranged on the tube sheet 2-1 joined together (illustrated with the EGR gas outlet side omitted, the same applies hereinafter) to form a heat transfer tube group. The bonnet 3 having a substantially rectangular cross-sectional shape along the axis of the shell body 2 is integrally attached to the outside via the tube sheet 2-1. In addition, the cross-sectional shape of the cross section of the bonnet 3 in this example is formed in a cylindrical shape corresponding to the cross-sectional shape of the cylindrical shell body 2 as shown in FIG. The side surface of the bonnet 3, that is, the EGR gas inflow pipe 4 is joined in the radial direction, the EGR gas inflow port 4-1 is formed at the joined part, and the vertical wall surface facing the tube sheet 2-1 of the bonnet 3. 3-1. Concentrically with the axis of the EGR gas inlet pipe 4 and at a predetermined distance from the EGR gas inlet 4-1 so as to be parallel to the EGR gas inlet pipe 4 A corrugated plate made of SUS304L austenitic stainless steel having a thickness of 0.5 mm is pre-joined as a guide plate 5, but the guide plate 5 in this embodiment is substantially an EGR gas as shown in FIG. It is concentric and parallel to the inflow pipe 4 and is formed in a wave shape at a position away from the EGR gas inlet 4-1 by a predetermined distance. Thus, the multi-tube heat exchanger 1 according to the first embodiment of the present invention as shown in FIG. 1 is partially omitted, and the obtained multi-tube heat exchanger 1 is used for the EGR gas cooling device. As a result of being incorporated in the gas flow path in the EGR gas cooling system and subjected to the cooling performance test, the high temperature EGR gas that flows through the EGR gas inlet pipe 4 and flows into the hood 3 from the EGR gas inlet 4-1 When flowing in parallel with the EGR gas inflow pipe 4, the flow is complicatedly stirred by the corrugated guide plate 5 provided at a position slightly away from the EGR gas inflow port 4-1. A vortex that circulates in the cylindrical bonnet 3 over the plate 5 is formed and introduced into the heat transfer tube 2-2 over time. As a result, the flow rate and flow rate distribution of the EGR gas are made uniform, and the shell body Heat transfer tubes 2- The EGR gas discharged from the hood on the EGR gas outlet side is cooled to a predetermined temperature range by efficiently exchanging heat to the cooling jacket on the outer periphery of the heat transfer tube. It was confirmed that

  The manufacturing method of the cylindrical bonnet 3 according to the present embodiment is not particularly limited, and is manufactured using various types of stainless steel and other steel pipes, castings, forgings, and the like as an EGR gas inlet 4-1. Are formed by pressing, hydraulic bulging, and casting. In addition, in the present example, welding is employed for joining the tube sheet 2-1 and the shell body 2, the tube sheet 2-1 and the heat transfer tube 2-2, and the tube sheet 2-1 and the bonnet 3. For joining the bonnet 3 to the shell body 2, a flange is provided on the shell 2 side of the bonnet 3, and similarly, a connection by bolting with a flange previously attached to the shell body 2 or brazing is preferably employed. The

  As shown in FIG. 3, the guide plate 5a is formed in a substantially V shape, and at the same time, a plurality of through holes 5a-1 and slits 5a-2 are arbitrarily formed on the plate-like surface, and the V-shaped top portion is formed. However, except that the V-shaped center line is provided substantially in parallel with the EGR gas inflow pipe 4a on the extension line of the axis of the EGR gas inflow pipe 4a, a multi-tube is provided. A heat exchanger 1a (not shown, the same applies below) was obtained. As a result of incorporating the obtained multi-tube heat exchanger 1a according to this example into the gas flow path in the EGR gas cooling system and subjecting it to the same cooling test as in Example 1, in addition to the V-shaped guide plate 5a, It is confirmed that the plurality of through holes 5a-1 and slits 5a-2 formed on the plate surface further promote the stirring action on the flow of EGR gas, and the cooling efficiency equal to or higher than that of Example 1 can be obtained. It was.

  The guide plate 5b is formed into a substantially arcuate curved surface that curves backward from the EGR gas inlet 4b-1, and at the same time, a plurality of through holes 5b-1 and slits 5b- As shown in FIG. 4, the central portion of the guide plate 5b having an arcuate curved surface is provided on the extension line of the axis of the EGR gas inflow pipe 4b and perpendicular to the EGR gas inflow pipe. A multitubular heat exchanger 1b was obtained in the same manner as in Example 2 except that. The obtained multi-tube heat exchanger 1b according to the present example was incorporated into a gas flow path in the EGR gas cooling system and subjected to the same cooling test as in Example 2. As a result, in addition to the guide plate 5b having an arcuate curved surface, It is confirmed that the plurality of through holes 5b-1 and slits 5b-2 formed on the plate surface promote the stirring action on the flow of EGR gas and can obtain substantially the same cooling efficiency as in Example 2. It was done.

  The guide plate 5c is basically a flat plate and is inclined with respect to the axis of the EGR gas inflow tube 4c as shown in FIG. 5, and at the same time, a plurality of through holes 5c-1 are arbitrarily formed on the plate-like surface. The slit 5c-2 was formed, and the others were the same as in Example 3 to obtain a multi-tube heat exchanger 1c. The obtained multi-tube heat exchanger 1c according to the present example was incorporated into a gas flow path in the EGR gas cooling system and subjected to the same cooling test as in Example 3, and as a result, the EGR gas inlet 4c-1 to the inside of the hood 3c The EGR gas that has flowed into the chamber becomes negative pressure by flowing along the inclined guide plate 5c, and is guided by the gap 5c-3 provided between the guide plate 5c and the inner peripheral surface of the bonnet 3c. The EGR gas staying in the positive pressure portion on the back surface of the plate 5c works to attract from the narrow gap 5c-3, and prevents carbon from accumulating on the back surface of the guide plate 5c to form on the plate surface. In consideration of the stirring action provided by the plurality of through holes 5c-1 and slits 5c-2, the amount of gas introduced into each heat transfer tube and the flow velocity are made more uniform, which is substantially equivalent to that of the third embodiment. Cooling efficiency It has been confirmed.

  The bonnet 3g in the present embodiment corresponds to the cross-sectional shape of the shell body 2d (not shown) having a rectangular cross section with a substantially square cross section, and the cross-sectional shape of the cross section of the bonnet 3g is as shown in FIG. The EGR gas inflow pipe 4g is joined through the outer peripheral surface 3g-2 of the axial center portion on the side surface of the bonnet 3g, and the EGR gas inlet 4g-1 is formed at the joined portion. Further, a predetermined distance from the EGR gas inlet 4g-1 is concentric with the vertical wall surface 3g-1 of the bonnet 3g facing the tube sheet 2b-1 and concentric with the axis of the EGR gas inlet pipe 4g. A guide plate 5g made of a corrugated plate substantially the same as that of the first embodiment is incorporated in substantially the same manner as in the first embodiment so as to be parallel to the EGR gas inlet pipe 4g. There. In this way, a multi-tube heat exchanger 1d (not shown, the same applies hereinafter) according to the present embodiment is formed, and the obtained multi-tube heat exchanger 1d constitutes an EGR gas cooling device, and EGR gas cooling As a result of being incorporated into the gas flow path in the system and subjected to the cooling performance test under the same conditions as in Example 1, the high temperature of the high temperature flowing through the EGR gas inlet pipe 4g and flowing into the bonnet 3g through the EGR gas inlet 4g-1 The EGR gas is agitated in a complicated manner by a corrugated guide plate 5g provided at a position slightly away from the EGR gas inlet 4g-1, and passes through the guide plate 5g to form a substantially square rectangular tubular bonnet. As a result, the flow rate and flow rate of the EGR gas are made uniform and distributed to the plurality of heat transfer tubes 2d-2 in the shell main body 2d almost uniformly, and the heat transfer tubes are formed. Outside Heat exchange to the cooling jacket is efficiently promoted, EGR gas discharged from the EGR gas outlet side of the hood, it was confirmed to be cooled to a predetermined temperature range.

  The cross-sectional shape along the axis of the shell body 2e of the bonnet 3h is formed in a substantially trapezoidal shape as shown in FIG. 10, and a cylindrical EGR gas inflow pipe 4h is formed through substantially the central portion in the longitudinal direction of the outer peripheral surface. Joining and forming the EGR gas inlet 4h-1, at the same time, at a position slightly away from the EGR gas inlet 4h-1, the inner surface 3h-3 of the side wall of the bonnet 3h is arbitrarily attached to the plate surface A multi-tube heat exchanger 1e is formed in substantially the same manner as in Example 5 except that a corrugated guide plate 5h in which a slit 5h-2 and a through hole 5h-1 having a desired shape are formed is previously incorporated. The resulting multi-tube heat exchanger 1e constitutes an EGR gas cooling device, which is incorporated into a gas flow path in the EGR gas cooling system, and subjected to a cooling performance test under the same conditions as in Example 5, Equivalent excellent cooling efficiency It was confirmed that may be.

  The cross-sectional shape along the axis of the shell main body 2f of the bonnet 3i is formed in a semi-elliptical shape as shown in FIG. 11, and passes through the upper part of the longitudinal center of the outer peripheral surface substantially in the longitudinal direction. To form the EGR gas inlet 4i-1, and at the same time, at a position slightly away from the EGR gas inlet 4i-1, via the inner peripheral surface 3i-3 of the side wall of the bonnet 3i, Except that the guide plate 5i having a curved surface in which slits 5i-2 and through-holes 5i-1 having any desired shape are formed is previously incorporated, a multi-tubular heat exchange is performed in substantially the same manner as in the sixth embodiment. An EGR gas cooling device is formed by the obtained multi-tube heat exchanger 1f, and is incorporated into a gas flow path in the EGR gas cooling system, and is used for a cooling performance test under the same conditions as in Example 6. As a result, the spherical music The guide plate 5i having the above and the bonnet 3i having the inner peripheral surface 3i-3 formed in a semi-elliptical shape act synergistically, and the inflowing EGR gas causes a suitable swirl flow in the bonnet 3i. Each of the heat transfer tubes 2f-2 that is stirred while being incorporated in the multi-tube heat exchanger 1f is introduced with a substantially uniform flow rate and flow rate, and is equivalent to or better than the above embodiments. It was confirmed that cooling efficiency could be achieved.

  The cross-sectional shape along the axis of the shell body 2g of the bonnet 3j is formed in a semi-oval shape as shown in FIG. 12, and the EGR gas inflow pipe 4j is joined to the side surface of the bonnet 3j, that is, in the radial direction. An EGR gas inlet 4j-1 is formed at the joint portion, and the curved wall surface 3j-1 facing the tube sheet 2g-1 on the inner peripheral surface 3j-3 of the bonnet 3j is connected to the shaft of the EGR gas inlet pipe 4j. A corrugated plate substantially the same as that of the first embodiment so as to be parallel to the EGR gas inlet pipe 4j at a predetermined distance from the EGR gas inlet 4j-1 and concentric with the heart. The multi-tube heat exchanger 1g is formed in substantially the same manner as in Example 7 except that the guide plate 5j made of is previously incorporated, and the EGR gas cooling device is formed by the obtained multi-tube heat exchanger 1g. Configure and EGR Incorporated into the gas flow path in scan cooling system, the result subjected to cooling performance tested under the same conditions as in Example 7, it was confirmed that can achieve excellent cooling efficiency comparable to Example 7.

  The cross-sectional shape along the axis of the shell body 2h of the bonnet 3k is formed in a substantially semicircular shape (dome shape) having a partially curved surface as shown in FIG. The EGR gas inflow pipe 4k is joined, an EGR gas inlet 4k-1 is formed at the joined portion, and a substantially vertical wall surface 3k facing the tube sheet 2h-1 on the inner peripheral surface 3k-3 of the bonnet 3k. -1, concentrically with the axis of the EGR gas inflow pipe 4k and at a predetermined distance from the EGR gas inflow port 4k-1 so as to be parallel to the EGR gas inflow pipe 4k, A multi-tubular heat exchanger 1h was formed in substantially the same manner as in Example 8 except that a guide plate 5k made of a corrugated plate substantially similar to that in Example 8 was previously incorporated. By tube type heat exchanger 1h As a result of configuring an EGR gas cooling device, incorporating it into a gas flow path in the EGR gas cooling system, and subjecting it to a cooling performance test under the same conditions as in Example 8, the same excellent cooling efficiency as in Example 8 was achieved. Confirmed to get.

  The cross-sectional shape of the cross section of the bonnet 3l corresponds to the cross-sectional shape of the cross-section of the shell body 2i (not shown, the same applies hereinafter), and is formed into an elliptical cylindrical shape as shown in FIG. The EGR gas inflow pipe 4l is joined to the side of 3l, that is, in the radial direction, and an EGR gas inlet 4l-1 is formed at the joined part, and further, the tube sheet 2i-1 of the shell body 2i of the bonnet 3l is opposed. A guide plate 5l having a V-shaped cross section is built in the vertical wall surface 3l-1, and a plurality of through holes 5l-1 and slits 5l-2 are arbitrarily formed on the plate-like surface of the guide plate 5l. Example 1 except that the V-shaped top portion is provided on the extension line of the axis of the EGR gas inflow pipe 4l and the V-shaped center line is substantially parallel to the EGR gas inflow pipe 4l. Multi-tube heat exchange in the same way 1i is formed, and the obtained multi-tube heat exchanger 1i constitutes an EGR gas cooling device, which is incorporated into a gas flow path in the EGR gas cooling system, and is used for a cooling performance test under the same conditions as in Example 1. As a result, the bonnet 3l having an elliptical cross-sectional shape and the guide plate 5l having a V-shaped cross-section and provided with a plurality of through holes 5i-1 and slits 5i-2 on the plate surface act synergistically. The EGR gas that flowed in is stirred while generating a suitable swirling flow in the bonnet 3l, and has a substantially uniform flow velocity and flow rate in each of the heat transfer tubes 2i-2 incorporated in the multi-tube heat exchanger 1i. It was confirmed that excellent cooling efficiency equivalent to or higher than that of Example 1 can be achieved.

  The cross-sectional shape of the cross section of the bonnet 3m itself is formed into a rectangular rectangular cylinder as shown in FIG. 15, corresponding to the cross-sectional shape of the cross-section of the shell body 2j (not shown, the same applies hereinafter). Example 1 except that a guide plate 5m having substantially the same cross-sectional waveform as that of the above example is incorporated in a vertical wall surface 3m-1 facing the tube sheet 2j-1 of the 3m shell body 2j. The multi-tube heat exchanger 1j is formed in the same manner as described above, and the obtained multi-tube heat exchanger 1j constitutes an EGR gas cooling device, which is incorporated in the gas flow path in the EGR gas cooling system, and the first embodiment. As a result of being subjected to a cooling performance test under the same conditions as in Example 1, it was confirmed that excellent cooling efficiency equivalent to or higher than that of Example 1 could be achieved.

  The guide plate according to the present invention can be provided in various forms in addition to the above-described embodiments as long as the intended purpose can be achieved. For example, the corrugated guide of the above-described first embodiment By forming a plurality of through holes and / or slits in the plate 5, it is possible to allow fluid to flow between both surfaces of the guide plate 5, and to promote stirring of EGR gas in the bonnet 3. In the V-shaped guide plate 5a in Example 2, the guide plate 5b having an arcuate curved surface in Example 3, and the inclined guide plate 5c in Example 4, a straight flat plate material that does not form any through holes or slits is used. It is also possible to form only one of the through hole or slit, or the shape and density of the through hole or slit to be formed can be changed as appropriate. The Further, in the corrugated guide plate 5 in the first embodiment, the wave height and the corrugated pitch can be changed as appropriate, and the surface of the substantially V-shaped guide plate 5a in the second embodiment is corrugated. The V-shaped angle can be arbitrarily changed. In the guide plate 5b having an arcuate curved surface in the third embodiment, the curved R value can be appropriately changed, or curved surfaces having different curvature radii can be combined. In some cases, a vertical flat plate having no curved arcuate curved surface as shown in FIG. 8 is one option, and the inclination angle of the guide plate 5c provided in an inclined manner in the fourth embodiment is determined. It is also possible to arbitrarily change, and no gap is provided between the inner peripheral surface of the bonnet 3d as shown in FIG. 6, or the gap 5e-3 is extremely narrowed as shown in FIG. Along with the guide plate 5e It is also possible to design so as not to form a through-hole or a slit in ones. In addition, these forms are appropriately and appropriately changed in design according to the capacity of the multi-tubular heat exchanger to be formed and the required reference value, and can maximize the functions of these devices. It is.

  As is clear from the above embodiments, the shell-and-tube multi-tubular heat exchanger for the EGR gas cooling device according to the present invention is connected to the EGR gas inflow side of the shell body through a tube sheet. The cross section of the cross section of the cross section of the cross section of the cross section of the cross section of the cross section of the cross section of the cross section of the cross section along the axis of the shell body. Corresponding to the cross-sectional shape of the cross-section of the shell body, the shape is formed into a substantially circular cross section including a square or a rectangle, a substantially circular cross section including an ellipse, or a shape partially having an inclined surface or a curved surface, An EGR gas inflow pipe is provided in a radial direction of the outer peripheral surface, and a predetermined wall is provided on the wall surface of the bonnet facing the tube sheet from the EGR gas inflow port of the EGR gas inflow pipe. In spite of the simple structure of providing a guide plate consisting essentially of a metal flat plate, the flow of the high-temperature EGR gas flowing into the bonnet is rectified, The introduced EGR gas flow is configured to be evenly distributed and introduced into a plurality of heat transfer tubes arranged at regular intervals in the tube sheet. Therefore, the EGR gas introduced into the EGR gas cooling device is distributed evenly and introduced into the cooling device main body while maintaining a uniform flow velocity distribution, so that the heat exchange performance of the EGR gas cooling device is maximized. This makes it possible to achieve excellent cooling efficiency and contribute greatly to energy saving. In addition, the guide plate according to the present invention can be manufactured by a very simple process, and the obtained effect is remarkably excellent although the means for attaching the guide plate to the bonnet is easy. The attached multitubular heat exchanger is expected to be widely adopted as a multitubular heat exchanger in the technical field, such as being able to reduce the size and weight of the EGR gas cooling device at low cost.

It is a principal part side view which shows typically the shell main body and bonnet of the multi-tube heat exchanger which concerns on 1st Example of this invention. It is a principal part cutting front view which shows typically the bonnet of the Example, a guide plate, and the flow of EGR gas. It is principal part sectional drawing which shows typically the bonnet of the 2nd Example which concerns on this invention, a guide plate, and the flow of EGR gas. It is principal part sectional drawing which shows typically the bonnet of 3rd Example which concerns on this invention, a guide plate, and the flow of EGR gas. It is principal part sectional drawing which shows typically the bonnet of 4th Example which concerns on this invention, a guide plate, and the flow of EGR gas. It is principal part sectional drawing which shows typically the bonnet of another Example which concerns on this invention, the guide plate, and the flow of EGR gas. It is principal part sectional drawing which shows typically the bonnet of another Example based on this invention, the guide plate, and the flow of EGR gas. It is principal part sectional drawing which shows typically the bonnet of another Example based on this invention, the guide plate, and the flow of EGR gas. It is principal part sectional drawing which shows typically the bonnet in 5th Example which concerns on this invention, a guide plate, and the flow of EGR gas. It is a principal part side view which shows typically the shell main body of the multitubular heat exchanger by 6th Example which concerns on this invention, the bonnet which incorporated the guide plate, and the flow of EGR gas. It is a principal part side view which shows typically the shell main body, the bonnet which incorporated the guide plate, and the flow of EGR gas by the 7th Example by this invention. It is a principal part side view which shows typically the shell main body and the bonnet which incorporated the guide plate of the multitubular heat exchanger by 8th Example which concerns on this invention. It is a principal part side view which shows typically the shell main body of the multi-tube heat exchanger by 9th Example which concerns on this invention, and the bonnet which incorporated the guide plate. It is principal part sectional drawing which shows typically the bonnet in the 10th Example which concerns on this invention, a guide plate, and the flow of EGR gas. It is principal part sectional drawing which shows typically the bonnet in the 11th Example which concerns on this invention, a guide plate, and the flow of EGR gas. A conventional multi-tube EGR gas cooling device is shown, (a) is a partially cutaway side view, and (b) is a plan view schematically showing an example of an arrangement state of heat transfer tubes according to the main part. The other multi-tube type EGR gas cooling device of another prior art example is shown, (a) is the partially broken longitudinal side view, (b) is the front view, (c) is the sectional view on the AA line in (a). is there.

Explanation of symbols

1, 1e, 1f, 1g, 1h Multi-tube heat exchanger 2, 2e, 2f, 2g, 2h Shell body 2-1, 2e-1, 2f-1, 2g-1, 2h-1 Tube sheet 2-2 2e-2, 2f-2, 2g-2, 2h-2 Heat transfer tubes 3, 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h,
3i, 3j, 3k, 3l, 3m Bonnet 3-1, (3g-1), 3k-1 Vertical wall surface 3h-1 Inclined wall surface 3i-1, 3j-1 Curved wall surface 3-2, 3g-2, 3h-2 3i-2, 3j-2, 3k-2,
3l-2, 3k-2 outer peripheral part 3-3, 3g-3, 3h-3, 3i-3, 3j-3, 3k-3,
3l-3, 3m-3 inner peripheral surface 4, 4a, 4b, 4c, 4d, 4e, 4f, 4g,
4h, 4i, 4j, 4k, 4l, 4m EGR gas inlet pipe 4-1, 4a-1, 4b-1, 4c-1, 4d-1, 4e-1, 4f-1,
4g-1, 4h-1, 4i-1, 4j-1, 4k-1, 4l-1,
4m-1 EGR gas inlet 5, 5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i,
5j, 5k, 5l, 5m Guide plate 5a-1, 5b-1, 5c-1, 5h-1, 5i-1, 5l-1 Through hole 5a-2, 5b-2, 5c-2, 5h-2, 5i-2, 5l-2 slit 5c-3, 5e-3, 5f-3, 5f-4, 5h-3, 5i-3 gap g EGR gas

Claims (12)

In the shell-and-tube type multi-tube heat exchanger in the EGR gas cooling device, a bonnet integrally connected to the EGR gas inlet side of the shell body constituting the multi-tube heat exchanger via a tube sheet, A cross-sectional shape along the axial center of the shell body is formed in a substantially rectangular shape, and an EGR gas inflow pipe is provided in the radial direction of the outer peripheral surface thereof, and the EGR gas is provided on a wall surface facing the tube sheet in the bonnet. A multi-tube heat exchanger for an EGR gas cooling apparatus, characterized in that a guide plate is provided so as to be a predetermined distance from the inlet of the inflow pipe. 2. The EGR gas according to claim 1, wherein a cross-sectional shape along the axis of the shell body of the bonnet is substantially semicircular, substantially trapezoidal, or partially formed with an inclined surface or a curved surface. Multi-tube heat exchanger for cooling equipment. The cross-sectional shape of the cross section of the bonnet is a rectangle, a substantially rectangular shape, a substantially oval shape, or a shape having a partially inclined surface or a curved surface corresponding to the cross-sectional shape of the cross section of the shell body. Item 3. The multi-tube heat exchanger for an EGR gas cooling device according to Item 1 or 2. 4. The guide plate according to claim 1, wherein the guide plate is concentric and parallel to the axis of the EGR gas inflow pipe and has a wave shape with respect to the flow of the EGR gas that flows in. A multitubular heat exchanger for an EGR gas cooling device as described in the paragraph. 5. The EGR gas cooling according to claim 1, wherein the guide plate is formed in a substantially V shape having a top portion thereof on an extension line of an axis of the EGR gas inflow pipe. Multi-tube heat exchanger for equipment. 6. The EGR gas cooling apparatus according to claim 1, wherein the guide plate is a flat plate provided concentrically and vertically with respect to an axis of the EGR gas inflow pipe. Multi-tube heat exchanger. The EGR gas cooling device according to any one of claims 1 to 6, wherein the guide plate is concentric and perpendicular to the axis of the EGR gas inflow pipe and has an arcuate curved surface. Multi-tube heat exchanger. The multi-tube heat exchanger for an EGR gas cooling apparatus according to any one of claims 1 to 7, wherein the guide plate is provided to be inclined with respect to an axis of the EGR gas inflow pipe. The EGR gas cooling device according to any one of claims 1 to 8, wherein a gap is provided at a predetermined interval between the guide plate and a bonnet inner peripheral surface in the vicinity of the EGR gas inlet. Multitubular heat exchanger. The multi-tubular heat exchanger for an EGR gas cooling apparatus according to any one of claims 1 to 9, wherein at least one through hole or slit is formed in the guide plate. The guide plate is made of a metal plate material, and the joining means to the inner wall surface of the bonnet is appropriately selected from welding, brazing, sticking, and other joining methods, and joined together. Item 11. A multi-tube heat exchanger for an EGR gas cooling device according to any one of Items 1 to 10. The metal plate material forming the guide plate is made of austenitic stainless steel such as SUS304, SUS304L, SUS316, SUS316L, and the thickness thereof is 0.2 to 0.5 mm. The multi-tube heat exchanger for an EGR gas cooling device according to any one of the above.