EP3026387A1

EP3026387A1 - Heat exchange component

Info

Publication number: EP3026387A1
Application number: EP15196478.0A
Authority: EP
Inventors: Masahiro Tokuda; Tatsuo Kawaguchi; Makoto Miyazaki
Original assignee: NGK Insulators Ltd
Current assignee: NGK Insulators Ltd
Priority date: 2014-11-27
Filing date: 2015-11-26
Publication date: 2016-06-01
Anticipated expiration: 2035-11-26
Also published as: CN105651106A; JP6404691B2; JP2016102605A; US20160153719A1; EP3026387B1

Abstract

There is provided a heat exchange component capable of controlling temperatures of fluids between which heat exchange is to be performed. A heat exchange component 30 includes a honeycomb structure 1 having partition walls extending through the honeycomb structure from a first end face 2 (2a) to a second end face 2 (2b) to define a plurality of cells forming a through channel of a first fluid, and including a ceramic material as a main component, a covering member 11 made of a metal and fitted into a circumference of the honeycomb structure 1, a tubular passing portion 32 disposed to come in contact with a circumference of the covering member 11 and forming a through channel of a second fluid, and a circumferential passing portion 33 disposed in a circumference of the tubular passing portion, containing the tubular passing portion 32, and constituting a through channel through which a third fluid is passed to come in contact with the tubular passing portion 32 and the covering member 11.

Description

"The present application is an application based on JP-2014-240567 filed on 11/27/2014 with Japan Patent Office, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a heat exchange component to perform heat exchange between a plurality of fluids.

Description of the Related Art

Improvement of a fuel efficiency of a car is demanded, and for the purpose of preventing deterioration of the fuel efficiency when an engine is cold at, e.g., startup of the engine, a system is expected in which cooling water, engine oil, automatic transmission fluid (ATF) or the like is warmed in early stages to decrease friction losses. Alternatively, for the purpose of activating an exhaust gas purifying catalyst in early stages, a system is expected in which the catalyst is heated.
For the improvement of the fuel efficiency of the car, it is required that an oil temperature is raised in early stages. Consequently, for the purpose of setting the car engine or transmission oil at an optimum temperature, an oil warmer is used to perform heat exchange between the cooling water and the oil. However, the temperature of the cooling water is low immediately after the startup of the engine, and it takes much time to raise the temperature of the cooling water. As a result, even when the oil warmer is used, there is the problem that it takes much time until the temperature of the oil rises.
To rapidly raise the oil temperature at the startup of the engine, it is expected that not only the cooling water but also exhaust heat of an exhaust gas are utilized as heat sources. For example, in Patent Document 1, there is described a heat exchanger constituted of a honeycomb structure (a first fluid passing portion) and a casing (a second fluid passing portion). According to this heat exchanger, it is possible to perform heat exchange between a high-temperature exhaust gas flowing through the first fluid passing portion and a low-temperature liquid flowing through the second fluid passing portion.
[Patent Document 1] WO 2011/071161 A1

SUMMARY OF THE INVENTION

However, for example, when oil is passed as a fluid, the oil has poor heat transfer properties, and hence there is a possibility that the oil is locally excessively heated to cause problems such as quality deterioration and burning damages. That is, in the case of heat exchange between two fluids of a first fluid and a second fluid, heat is transferred from the fluid of a high temperature to the fluid of a low temperature, and hence the temperature of one fluid is dominated by the temperature of the other fluid. Therefore, it has been difficult to obtain a desirable temperature.
An object of the present invention is to provide a heat exchange component capable of controlling temperatures of fluids between which heat exchange is to be performed.
The present inventors have found that the above object can be achieved by disposing a tubular passing portion forming a through channel of a second fluid to come in contact with a circumference of a covering member which covers a honeycomb structure including a through channel of a first fluid and further disposing a circumferential passing portion containing the tubular passing portion. To achieve the above object, according to the present invention, a heat exchange component is provided as follows.

[1] A heat exchange component including a honeycomb structure having partition walls extending through the honeycomb structure from a first end face to a second end face to define a plurality of cells forming a through channel of a first fluid, and including a ceramic material as a main component, a covering member made of a metal and fitted into a circumference of the honeycomb structure, a second fluid passing portion disposed to come in contact with a circumference of the covering member and forming a through channel of a second fluid, and a third fluid passing portion disposed in a circumference of the second fluid passing portion, containing the second fluid passing portion and forming a through channel through which a third fluid is passed to come in contact with the second fluid passing portion and the covering member.
[2] The heat exchange component according to the above [1], wherein the second fluid passing portion is a tubular passing portion, and the tubular passing portion is wound around the circumference of the covering member to come in contact with the circumference and is spirally disposed.
[3] The heat exchange component according to the above [1], wherein the second fluid passing portion is a tubular passing portion, and the tubular passing portion is disposed to come in contact with the circumference of the covering member in a meandering manner.
[4] The heat exchange component according to the above [1], wherein the second fluid passing portion is disposed to come in contact with the circumference of the covering member in a lattice manner.
[5] The heat exchange component according to any one of the above [1] to [4], wherein (a contact area between the second fluid passing portion and the covering member)/(a circumferential surface area of the honeycomb structure) is from 0.01 to 0.3.
[6] The heat exchange component according to any one of the above [1] to [5], wherein (a contact surface area of the second fluid passing portion which comes in contact with the third fluid)/(a volume of the second fluid passing portion) is from 0.3 to 0.8.
[7] The heat exchange component according to any one of the above [1] to [6], wherein a distance between a tubular passing portion and the adjacent tubular passing portion forming the second fluid passing portion is from 0.3 to 7.0 mm.

A heat exchange component has a through channel of a third fluid in addition to a through channel of a first fluid and a through channel of a second fluid to perform heat exchange, temperatures of the first fluid and the second fluid are controlled by the third fluid, and hence excessive temperature rise can be prevented. In particular, the heat exchange component includes a tubular passing portion disposed to come in contact with a circumference of a covering member which covers a honeycomb structure, and forming the through channel of the second fluid, and a circumferential passing portion containing the tubular passing portion, whereby the temperatures of the respective fluids are easy to be controlled. The heat exchange component of the present invention can be utilized even with a fluid (e.g., oil) having low heat transfer properties.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1A is a schematic view showing a heat exchange component of Embodiment 1 in an axial direction;
Fig. 1B is a schematic view showing a cross section vertical to the axial direction of the heat exchange component of Embodiment 1;
Fig. 2A is a schematic view showing a honeycomb structure;
Fig. 2B is a schematic view showing that the honeycomb structure and a covering member are integrated;
Fig. 2C is a schematic view showing a heat exchange member in which the honeycomb structure and the covering member are integrated;
Fig. 3A is a cross-sectional view in the axial direction of Embodiment 1;
Fig. 3B is a cross-sectional view showing an embodiment in which a sectional shape of a tubular passing portion is elliptic;
Fig. 3C is a cross-sectional view showing an embodiment in which a sectional shape of a tubular passing portion is rectangular;
Fig. 4A is a schematic view showing a heat exchange component of Embodiment 2 in an axial direction;
Fig. 4B is a schematic view showing a cross section vertical to the axial direction of the heat exchange component of Embodiment 2;
Fig. 5A is a schematic view showing a heat exchange component of Embodiment 3 in an axial direction;
Fig. 5B is a schematic view showing a cross section vertical to the axial direction of the heat exchange component of Embodiment 3;
Fig. 6 is a schematic view showing a heat exchange component of Embodiment 4 in an axial direction; and
Fig. 7 is a schematic view showing a heat exchange component of Comparative Example 1 in an axial direction.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and changes, modifications and improvements can be added to the invention without departing from the gist of the invention.

(Embodiment 1)

(Heat Exchange Component)

Fig. 1A and Fig. 1B show Embodiment 1 of a heat exchange component 30. The heat exchange component 30 includes a honeycomb structure 1 having partition walls 4 extending through the honeycomb structure from a first end face 2 (2a) to a second end face 2 (2b) to define a plurality of cells 3 forming a through channel of a first fluid, and including a ceramic material as a main component, a covering member 11 made of a metal and fitted into a circumference of the honeycomb structure 1, a tubular passing portion 32 disposed to come in contact with a circumference of the covering member 11 and forming a through channel of a second fluid, and a circumferential passing portion 33 disposed in a circumference of the tubular passing portion, containing the tubular passing portion 32 and forming a through channel through which a third fluid is passed to come in contact with the tubular passing portion 32 and the covering member 11. That is, the heat exchange component 30 includes a first fluid passing portion 25 of the honeycomb structure 1 which is the through channel of the first fluid, a second fluid passing portion 26 of the tubular passing portion 32 which is the through channel of the second fluid, and a third fluid passing portion 27 of the circumferential passing portion 33 which is the through channel of the third fluid. In the heat exchange component 30, the fluids are passed through the through channels without being mixed with each other. That is, heat exchange between the fluids is mutually performed while separating the fluids.
The heat exchange component 30 not only can perform the heat exchange between the first fluid and the second fluid but also includes the through channel of the third fluid on a circumferential side of the second fluid, and hence the heat exchange component has a function of enabling temperature control of the second fluid. For example, when the first fluid has a higher temperature than the second fluid and the third fluid has a lower temperature than the second fluid before the heat exchange, the temperature of the second fluid rises due to the heat exchange between the second fluid and the first fluid, but the temperature can be lowered by the heat exchange between the second fluid and the third fluid.
The heat exchange component 30 has the through channel of the third fluid in addition to the through channel of the first fluid and the through channel of the second fluid to perform the heat exchange, so that the temperatures of the first fluid and the second fluid can be controlled by the third fluid, and excessive temperature rise can be prevented. For example, when the heat exchange component 30 is attached to a vehicle and an exhaust gas as the first fluid, oil as the second fluid and water as the third fluid are passed, heat from the exhaust gas is transferred to the oil in the tubular passing portion 32 via a contact portion between the circumference of the covering member 11 and the tubular passing portion 32. That is, the heat is transferred from the exhaust gas to the oil, and hence the temperature of the oil can rapidly be raised. In addition, the water is passed as the third fluid, and hence even when the temperature of the exhaust gas heightens, an oil contact surface is not excessively heated, and deterioration of the oil can be prevented. Specifically, the heat exchange component can be utilized as in (a) to (c) mentioned below.

(a) When the oil temperature is low (the oil is to be heated), the heat from the exhaust gas is transferred to the tubular passing portion 32 via the contact portion between the circumference of the covering member 11 and the tubular passing portion 32. In consequence, the temperature of the oil flowing through the tubular passing portion 32 can be raised. In addition, the tubular passing portion 32 is wound in a coil manner (a spiral manner) to lengthen retention time of the oil, and hence the temperature of the oil having poor heat transfer properties can efficiently be raised.
(b) After the oil temperature rises or even when the exhaust gas temperature is high, cooling water is in contact with a circumferential surface 11h of the covering member 11 and the circumference of the tubular passing portion 32, the oil contact surface is not excessively heated, and hence the deterioration of the oil can be prevented.
(c) Flow rates of the cooling water and the oil are varied, and hence balance adjustment of an amount of the heat to be transferred can be achieved. Specifically, when the oil is to be preferentially heated, an amount of the cooling water is decreased to heighten the water temperature, a temperature difference between the cooling water and the oil is increased, and hence the amount of the heat to be transferred to the oil can be increased. In addition, when the oil temperature excessively rises, the amount of the cooling water is increased, and hence the oil temperature rise can be inhibited.

Additionally, in the heat exchange component 30, inflow of each fluid is turned ON/OFF, and hence it is possible to only perform heat exchange between the through channels which the heat exchange is to be performed. For example, when the first fluid is a gas, the second fluid is a liquid and the third fluid is a liquid and the third fluid is only turned OFF (does not flow inside), it is possible to perform the heat exchange only between the gas (the first fluid) and the liquid (the second fluid). Additionally, when the first fluid is only turned OFF (does not flow inside), it is possible to perform the heat exchange only between the liquid (the second fluid) and the liquid (the third fluid). Alternatively, when all the fluids flow inside, it is possible to perform the heat exchange between two of the gas (the first fluid) and the liquid (the second fluid) and the liquid (the third fluid). That is, the heat exchange component 30 is usable in the heat exchange between the two fluids by inhibiting one of the first fluid to the third fluid from flowing inside. Alternatively, the heat exchange component 30 may include a through channel other than the first fluid passing portion 25, the second fluid passing portion 26 and the third fluid passing portion 27 as another fluid through channel, and may be used in heat exchange among four fluids or more.
Hereinafter, each constituent member will specifically be described.

(Honeycomb Structure)

Fig. 2A shows a schematic view of the honeycomb structure 1. The honeycomb structure 1 is made of a pillar-shaped ceramic material, and has fluid through channels extending through the honeycomb structure from the first end face 2 (2a) to the second end face 2 (2b) in an axial direction. The honeycomb structure 1 has the partition walls 4, and a large number of cells 3 forming the fluid through channels are defined by the partition walls 4. The honeycomb structure 1 has the partition walls 4, and hence the heat from the fluid flowing through the honeycomb structure 1 can efficiently be collected and transferred to the outside.
An outer shape of the honeycomb structure 1 is not limited to a round pillar shape, and a cross section of the honeycomb structure which is vertical to the axial (longitudinal) direction may be elliptic. In addition, the outer shape of the honeycomb structure 1 may be prismatic columnar, i.e., the cross section vertical to the axial (longitudinal) direction may be a quadrangular shape or other polygonal shape.
In the heat exchange component 30, the honeycomb structure 1 includes the ceramic material as the main component, and hence thermal conductivities of the partition walls 4 and a circumferential wall 7 heighten, and as a result, it is possible to efficiently perform the heat exchange in which the partition walls 4 and the circumferential wall 7 are interposed. It is to be noted that when it is described in the present description that the ceramic material is included as the main component, it is meant that 50 mass% or more of the ceramic material is included.
The porosity of the honeycomb structure 1 is preferably 10% or less, more preferably 5% or less, and further preferably 3% or less. When the porosity is 10% or less, the thermal conductivity can improve.
In particular, when heat transfer properties are taken into consideration, the honeycomb structure 1 preferably includes SiC (silicon carbide) having high heat transfer properties as the main component. It is to be noted that the main component is silicon carbide whose content ratio is 50 mass% or more of the honeycomb structure 1.
Further specifically, as the material of the honeycomb structure 1, there can be employed Si-impregnated SiC, (Si+Al)-impregnated SiC, metal composite SiC, recrystallized SiC, Si₃N₄, SiC or the like. However, in the case of a porous body, a high thermal conductivity might not be obtained, and hence to obtain the high thermal conductivity, a dense structure (a porosity of 5% or less) is preferably employed, and Si-impregnated SiC or (Si+Al)-impregnated SiC is preferably employed. SiC has a high thermal conductivity and is easy to radiate heat, but SiC impregnated with Si exhibits a high thermal conductivity or heat resistance, is also densely formed and indicates a sufficient strength as a heat transfer member. For example, in the case of a porous body of SiC (silicon carbide), the thermal conductivity is about 20 W/(m·K), but in the case of the dense body, the thermal conductivity can be about 150 W/(m·K). As to measurement of the thermal conductivity, a value of a test piece cut out from the honeycomb structure 1 at room temperature is calculated by using a thermal diffusivity measured in an AC method, specific heat measured in a DSC (differential scanning calorimetry) method and a value of a density measured in an Archimedes method.
As a cell shape of the cross section vertical to the axial direction of the cells 3 of the honeycomb structure 1, a desirable shape may suitably be selected from a round shape, an elliptic shape, and polygonal shapes such as a triangular shape, a quadrangular shape and a hexagonal shape.
There is not any special restriction on a cell density (i.e., the number of cells per unit sectional area) of the honeycomb structure 1, and the cell density may suitably be designed in accordance with a purpose, and is preferably in a range of 25 to 2000 cells/square inch (4 to 320 cells/cm²). When the cell density is 25 cells /square inch or more, not only a strength of the partition walls 4 but also a strength of the honeycomb structure 1 itself and an effective GSA (geometric surface area) can sufficiently be obtained. In addition, when the cell density is 2000 cells/square inch or less, a pressure loss in a case where a heat medium flows can be prevented from being increased.
An isostatic strength of the honeycomb structure 1 is preferably 1 MPa or more and further preferably 5 MPa or more. When the honeycomb structure has such a strength, a durability can sufficiently be obtained.
The isostatic strength is obtained by the following method. A urethane rubber sheet having a thickness of 0.5 mm is wound around the circumferential surface of the honeycomb structure 1. Furthermore, a disc having a thickness of 20 mm and made of aluminum is disposed on each of both end faces of the honeycomb structure via a round urethane rubber sheet. The aluminum disc and the urethane rubber sheet each having the same radius as a radius of each end face of the honeycomb structure is used. A vinyl tape is wound along a circumference of the aluminum disc, to seal a space between the circumference of the aluminum disc and the urethane rubber sheet, thereby obtaining a testing sample.
The prepared testing sample is put in a pressure container in which water is contained. Further, a pressure is raised at a rate of 0.3 to 3.0 MPa/minute to apply a predetermined hydrostatic pressure to the testing sample, and breakdown of the honeycomb structure and generation of cracks are confirmed. Presence/absence of the generation of the cracks is judged by confirming breakdown noise during a test and visually checking an appearance of the honeycomb structure after the test, and when any cracks are not generated, the hydrostatic pressure is further raised to evaluate the isostatic strength.
A diameter of the honeycomb structure 1 is preferably 200 mm or less, and further preferably 100 mm or less. With such a diameter, a heat exchange efficiency can improve.
There is not any special restriction on a thickness (a wall thickness) of the partition walls 4 of the cells 3 of the honeycomb structure 1, and the thickness may suitably be designed in accordance with the purpose. The wall thickness is preferably from 0.1 to 1 mm, and further preferably from 0.2 to 0.6 mm. When the wall thickness is 0.1 mm or more, a mechanical strength can sufficiently be obtained, and damages due to impact or thermal stress can be prevented. In addition, when the wall thickness is 1 mm or less, it is possible to prevent the disadvantage that the pressure loss of the fluid increases or that the exchange ratio decreases.
A density of the partition walls 4 of the cells 3 of the honeycomb structure 1 is preferably from 0.5 to 5 g/cm³. When the density is 0.5 g/cm³ or more, the partition walls 4 have a sufficient strength, and it is possible to prevent the partition walls 4 from being broken by the pressure when the first fluid flows through the through channel. In addition, when the density is 5 g/cm³ or less, the honeycomb structure 1 can be lightened. When the density is in the above range, the honeycomb structure 1 can be strengthened, and an effect of improving the thermal conductivity can be obtained.
In the honeycomb structure 1, the thermal conductivity is preferably 50 W/(m·K) or more, more preferably from 100 to 300 W/(m·K), and further preferably from 120 to 300 W/(m·K). When the thermal conductivity is in this range, the heat transfer properties improve, and the heat in the honeycomb structure 1 can efficiently be discharged to the outside of the covering member 11.
In the heat exchange component 30, when the exhaust gas is passed as the first fluid, a catalyst is preferably loaded onto the partition walls 4 of the honeycomb structure 1. When the catalyst is loaded onto the partition walls 4 in this manner, CO, NO_x, HC or the like in the exhaust gas can be converted into a harmless substance by a catalyst reaction, and additionally reaction heat generated in the catalyst reaction is usable in the heat exchange. The catalyst for use in the honeycomb structure 1 of the present invention may contain at least one selected from the group consisting of noble metals (platinum, rhodium, palladium, ruthenium, indium, silver and gold), aluminum, nickel, zirconium, titanium, cerium, cobalt, manganese, zinc, copper, tin, iron, niobium, magnesium, lanthanum, samarium, bismuth and barium. The catalyst mentioned herein may be a metal, an oxide, or another compound.
An amount of the catalyst (a catalyst metal + a carrier) to be loaded onto the partition walls 4 of the cells 3 of the first fluid passing portion 25 of the honeycomb structure 1 through which the first fluid (a high temperature side) flows is preferably from 10 to 400 g/L, and when the catalyst is the noble metal, the amount is further preferably from 0.1 to 5 g/L. When the amount of the catalyst (the catalyst metal + the carrier) to be loaded is 10 g/L or more, a catalysis is easily developed. On the other hand, when the amount is 400 g/L or less, the pressure loss can be suppressed, and increase of manufacturing cost can be inhibited.

(Covering Member)

The covering member 11 is a tube made of a metal and fitted into the circumference of the honeycomb structure 1. In the present description, a combination of the honeycomb structure 1 and the covering member 11 is called a heat exchange member 10. As shown in Fig. 2B, the honeycomb structure 1 is inserted into the covering member 11 and integrated by shrink fitting, and as shown in Fig. 2C, the heat exchange member 10 can be formed. It is to be noted that when the honeycomb structure 1 is bonded to the covering member 11, press-in, brazing, diffusion bonding or the like may be used in addition to the shrink fitting.
The covering member 11 which covers the honeycomb structure 1 does not pass therethrough (is not permeated by) the first fluid or the second fluid, and the covering member preferably has suitable heat transfer properties, heat resistance and corrosion resistance. Examples of the covering member 11 include a metal tube and a ceramic tube. As a material of the metal tube, for example, stainless steel, titanium alloy, copper alloy, aluminum alloy, brass or the like is usable.
The covering member 11 covers a circumferential surface 7h of the honeycomb structure 1, and hence the first fluid flowing through the honeycomb structure 1 and the second fluid flowing through the outer side of the honeycomb structure 1 are passed without being mixed with each other, and the heat exchange between the fluids can be performed. In addition, the heat exchange member 10 includes the covering member 11, and hence the heat exchange member can easily be processed in accordance with a disposing place or a disposing method, and a degree of freedom is high. The heat exchange member 10 is strong even against impact from the outside, because the honeycomb structure 1 can be protected by the covering member 11.

(Tubular Passing Portion)

The tubular passing portion 32 is disposed to come in contact with the circumference of the covering member 11. The tubular passing portion 32 constituting the second fluid passing portion 26 is preferably made of a material which is not permeated by the second fluid or the third fluid and has suitable heat transfer properties, heat resistance and corrosion resistance. Examples of the material to form the tubular passing portion 32 include a metal and a ceramic material. As the metal, for example, stainless steel, titanium alloy, copper alloy, aluminum alloy, brass or the like is usable.
In Embodiment 1 shown in Fig. 1A and Fig. 1B, the tubular passing portion 32 is wound around the circumferential surface 11h of the covering member 11 to come in contact with the surface and is disposed in a spiral manner.
Examples of a sectional shape of the tubular passing portion 32 include a circle, an ellipse, and quadrangular shapes (a square and a rectangle), but the sectional shape is not limited to these examples. Embodiment 1 of Fig. 1A is an example where the sectional shape of the tubular passing portion 32 is round. In addition, Fig. 3A is a cross-sectional view of Embodiment 1 in the axial direction. The heat from the first fluid (e.g., the exhaust gas) is transferred to the second fluid (e.g., the oil) in the tubular passing portion 32 via the contact portion between the circumference of the covering member 11 and the tubular passing portion 32. Additionally, the third fluid (e.g., the water) is in contact with the circumferential surface 11h of the covering member 11 and the circumference of the tubular passing portion 32, and hence the third fluid can control the temperatures of the first fluid and the second fluid and prevent excessive temperature rise. In addition, Fig. 3B is a cross-sectional view showing an embodiment where the sectional shape of the tubular passing portion 32 is elliptic. Furthermore, Fig. 3C is a cross-sectional view showing an embodiment where the sectional shape of the tubular passing portion 32 is rectangular.

(Circumferential Passing Portion)

The circumferential passing portion 33 constituting the third fluid passing portion 27 contains the heat exchange member 10 (the honeycomb structure 1 and the covering member 11) and the tubular passing portion 32. There is not any special restriction on a shape of the circumferential passing portion 33 as long as the circumferential passing portion is disposed to contain the tubular passing portion 32 and the honeycomb structure 1. The circumferential passing portion 33 constituting the third fluid passing portion 27 preferably is not permeated by the third fluid, and has suitable heat transfer properties, heat resistance and corrosion resistance. Examples of a material constituting the circumferential passing portion 33 include a metal and a ceramic material. As the metal, for example, stainless steel, titanium alloy, copper alloy, aluminum alloy, brass or the like is usable.

(Manufacturing Method of Heat Exchange Component)

Next, a manufacturing method of the heat exchange component 30 will be described. First, a kneaded material including ceramic powder is extruded into a desirable shape, and a honeycomb formed body is prepared. As a material of the honeycomb structure 1, the abovementioned ceramic material is usable. However, for example, when the honeycomb structure 1 including a Si-impregnated SiC composite material as a main component is manufactured, a predetermined amount of SiC powder, a binder, water or an organic solvent is kneaded to obtain the kneaded material, and formed to obtain the honeycomb formed body having the desirable shape. Further, the honeycomb formed body is dried, and the honeycomb formed body is impregnated with metal Si and is fired in a decompressed inert gas or vacuum, whereby it is possible to obtain the honeycomb structure 1 in which the plurality of cells 3 forming the through channel of the gas are defined by the partition walls 4.
Subsequently, the temperature of the covering member 11 is raised, and as shown in Fig. 2B and Fig. 2C, the honeycomb structure 1 is inserted into the covering member 11 and integrated by the shrink fitting, so that the heat exchange member 10 can be formed. It is to be noted that when the honeycomb structure 1 is bonded to the covering member 11, press-in, brazing, diffusion bonding or the like may be used in addition to the shrink fitting.
Afterward, the tubular passing portion 32 made of the metal is disposed to come in contact with the heat exchange member 10. Afterward, the circumferential passing portion 33 covers these components, and the heat exchange component 30 constituted of three through channels can be obtained.

(Embodiment 2)

Fig. 4A and Fig. 4B show a heat exchange component 30 of Embodiment 2. A tubular passing portion 32 is disposed to come in contact with a circumference of a covering member 11 in a meandering manner. In Embodiment 2 shown in Fig. 4A, the tubular passing portion 32 meanders along an axial direction, but may meander along a peripheral direction.

(Embodiment 3)

Fig. 5A and Fig. 5B show a heat exchange component 30 of Embodiment 3. A tubular passing portion 32 is disposed to come in contact with a circumference of a covering member 11 in a lattice manner. Embodiment 3 shown in Fig. 5A includes an axial direction passing portion 32j along an axial direction and a peripheral direction passing portion 32k along a peripheral direction. Both ends of each of the plurality of axial direction passing portions 32j are connected to the peripheral direction passing portion 32k, a second fluid flowing through the peripheral direction passing portion 32k branches to flow through the axial direction passing portions 32j, and these fluids are then collected in the peripheral direction passing portion 32k.

(Embodiment 4)

Fig. 6 shows a heat exchange component 30 of Embodiment 4. In the embodiment of Fig. 6, a tubular passing portion 32 is wound around a circumference of a covering member 11 to come in contact with the circumference as in Embodiment 1, and is disposed in a spiral manner, and additionally, the tubular passing portion 32 is bent in an axial direction. In consequence, a length of the tubular passing portion 32 increases, heat exchange is easy to occur, and a heat exchange efficiency can improve. In Embodiment 4, the tubular passing portion 32 of Embodiment 1 is bent, but the bending of the tubular passing portion 32 in this manner is not limited to Embodiment 1, and can similarly be performed in the other embodiments.
In each of Embodiments 1 to 4, (a contact area between the tubular passing portion and the covering member)/(a circumferential surface area of the honeycomb structure) is preferably from 0.01 to 0.3, more preferably from 0.05 to 0.2, and further preferably from 0.1 to 0.2. An area of the circumferential surface 7h of the honeycomb structure 1 contributes to the heat exchange, and hence in the above formula, the circumferential surface area of the honeycomb structure 1 is a denominator. The larger a numeric value of the above formula is, the more the heat exchange efficiency between the first fluid and the second fluid can improve. However, for example, when the second fluid is oil, deterioration and burning damages of the oil are easy to occur. When the ratio is in this range, the heat exchange efficiency can improve, and the deterioration and burning damages of the second fluid can be prevented. Especially in Embodiments 2 and 3, to prevent the burning damages, an upper limit of the numeric value of the above formula is preferably suppressed.
In each of Embodiments 1 to 4, (a contact surface area of the tubular passing portion which comes in contact with the third fluid)/(a volume of the tubular passing portion) is preferably from 0.3 to 0.8, more preferably from 0.5 to 0.8, and further preferably from 0.7 to 0.8. The larger a numeric value is, the more the heat exchange efficiency between the second fluid and the third fluid can improve, and when the second fluid is the oil, the deterioration and burning damages of the oil are hard to occur. When the numeric value is larger, the heat exchange efficiency can improve, and the deterioration and burning damages of the second fluid can be prevented, but preparation becomes difficult, and a resistance of flow of the second fluid increases. Especially, in Embodiments 2 and 3, to prevent the burning damages, the numeric value of the above formula is preferably large.
In each of Embodiments 1 to 4, a distance between the tubular passing portion 32 and the adjacent tubular passing portion 32 forming the second fluid passing portion is preferably from 0.3 to 7.0 mm, further preferably from 0.3 to 4.0 mm, and further preferably from 0.3 to 2.0 mm. When the numeric value is small, the contact area between the tubular passing portion 32 and the covering member 11 can be large, but the preparation becomes difficult.

(Examples)

Hereinafter, the present invention will be described in more detail on the basis of examples, but the present invention is not limited to these examples.

(Example 1)

(Manufacturing of Honeycomb Structure)

A honeycomb structure 1 including a Si-impregnated SiC composite material as a main component was prepared as follows. First, a forming raw material obtained by kneading a predetermined amount of SiC powder, a binder, water, an organic solvent or the like was extruded into a desirable shape, and dried to obtain a honeycomb formed body. A lump of metal Si was mounted on the honeycomb formed body, and fired in vacuum or a decompressed inert gas. In this firing, the lump of metal Si mounted on the honeycomb formed body was molten, and a circumferential wall 7 and partition walls 4 were impregnated with metal Si. The honeycomb structure 1 prepared in this manner was a dense material in which metal Si was charged into spaces among SiC particles, and indicated high heat transfer properties having a thermal conductivity of about 150 W/(m·K). A shape of the honeycomb structure 1 had a diameter of 40 mm and a length of 100 mm, and in a cell structure portion, a thickness of the partition walls 4 was about 0.4 mm and a cell pitch was about 1.8 mm.

(Preparation of Fluid Through Channel)

A stainless metal tube (a covering member 11) was fitted into a circumferential surface 7h of the honeycomb structure 1 by shrink fitting, to manufacture a heat exchange member 10 (see Fig. 2B and Fig. 2C), and a tubular passing portion 32 made of stainless steel was disposed to come in contact with a circumference of the heat exchange member 10. Afterward, a circumferential passing portion 33 made of stainless steel covers their outer sides, and a fluid through channel constituted of three through channels was prepared (see Fig. 1A).

(Heat Exchange Efficiency Test)

A first fluid (a gas) was passed through cells 3 of the honeycomb structure 1 of the heat exchange member 10, a second fluid (oil) flowed into the tubular passing portion 32, a third fluid (water) flowed into the circumferential passing portion 33, and a heat exchange efficiency was measured. As the first fluid, an atmospheric gas was used, and the gas was passed through the cells 3 at a temperature of 400°C and at a flow rate of 10 g/sec (0.464 Nm³/min). In addition, as the second fluid, the oil was used, and was passed in a direction facing the first fluid at 60°C and at a flow rate of 10 L/min. As the third fluid, the water was used, and passed at 30°C and at a flow rate of 0 to 10 L/min. However, also in a case where the third fluid was not present (without the water), measurement was carried out, and a reference of "oil temperature drop from a state where the water was not present" was obtained.
A temperature of the first fluid flowing on an upstream side of 20 mm from inlets of the cells 3 of the heat exchange member 10 was defined as "an inlet gas temperature", and a temperature of the first fluid flowing on a downstream side of 200 mm from outlets of the cells 3 was defined as "an outlet gas temperature". A temperature of the oil passing an inlet of the tubular passing portion 32 was defined as "an inlet oil temperature", and a temperature of the oil passing an outlet of the tubular passing portion 32 was defined as "an outlet oil temperature". A temperature of the water passing an inlet of the circumferential passing portion 33 was defined as "an inlet water temperature", and a temperature of the water passing an outlet of the circumferential passing portion 33 was defined as "an outlet water temperature".
From these temperatures, a heat exchange efficiency (%) between the gas and the oil was calculated by the following equation. Heat exchange efficiency (%) = (the inlet gas temperature - the outlet gas temperature)/(the inlet gas temperature - the inlet oil temperature) x 100
Table 1 shows a result of a heat exchange efficiency test between the gas (the first fluid) and the oil (the second fluid) in a case where the water (the third fluid) was not present or in a case where the water (the third fluid) was not passed, and a result of a heat exchange efficiency test between the gas (the first fluid) and the oil (the second fluid) in a case where the water (the third fluid) was passed.

(Comparative Example 1)

(Manufacturing of Honeycomb Structure)

The same honeycomb structure 1 as in Example 1 was prepared.

(Preparation of Fluid Through Channel)

A stainless metal tube was fitted into a circumferential surface 7h of a honeycomb structure 1 by shrink fitting, to manufacture a heat exchange member 10, and the heat exchange member 10 was disposed in a casing 41 made of stainless steel. Comparative Example 1 was a heat exchange component 40 which did not include a tubular passing portion 32 differently from the above example (see Fig. 7). The casing 41 corresponded to a circumferential passing portion 33, but oil flowed into the circumferential passing portion 33. Additionally, in Example 1, the oil flowed into the tubular passing portion 32, but in Comparative Example 1, the tubular passing portion 32 was not disposed, a first fluid (a gas) was passed through cells 3 of the honeycomb structure 1 of the heat exchange member 10, and a second fluid (oil) flowed into the casing 41.

[Table 1]

	Flow rate of water (third fluid) [L/min]	Heat exchange efficiency between gas (first fluid) and oil (second fluid)	Oil burning damages	Oil temperature drop from state where water is not present [°C]
Comparative example 1 (without tubular passing portion)	Without water	27%	Present	0
Example 1 (With tubular passing portion)	Without water	33%	Present	0 (reference)
	0	32%	None		2
	5	32%	None	2.5
	10	32%	None		3

As shown in Fig. 1A, Example 1 had the tubular passing portion 32, and a way of use was usually assumed in which the oil flowed into the tubular passing portion 32 while the water flowed into the circumferential passing portion 33. However, as the reference of "the oil temperature drop from the state where the water was not present", measurement was carried out in the case where "the water was not present", but even when the oil burning damages were caused in the state where "the water was not present", the oil burning damages were removed in the state where the water was passed, and there were not any problems. Additionally, in Example 1, when the oil flowed even in the case where "the water was not present", a long contact distance (time) with the circumference of the heat exchange member 10 was acquired, the flow of the oil was easy to be disturbed, and hence the temperature of the whole oil was efficiently raised.
Additionally, in Example 1, in each of the case where "the water was not present" and the case where the water was passed, the heat exchange between the gas (the first fluid) and the oil (the second fluid) was efficiently performed, and the oil temperature was efficiently raised. Furthermore, the flow rate of the water was adjusted to enable oil temperature control in a broad temperature range. Additionally, when the water was used, disadvantages such as the oil burning damages onto a pipe inner wall were not seen.
On the other hand, in Comparative Example 1, the oil passed through a short route in the axial direction, and hence the contact distance (time) with the circumference of the heat exchange member 10 shortened. Furthermore, the flow of the oil was hard to be disturbed, and hence the temperature of the whole oil was hard to be raised. In Comparative Example 1, heat from the exhaust gas was directly transferred to the oil through the covering member 11, but the oil in the vicinity of the surface of the covering member 11 was excessively heated, and hence quality deterioration or the burning damages occurred. In addition, retention time of the oil was short, and the efficiency of the heat exchange was poor.
The heat exchange component of the present invention is usable in a use application in which heat exchange is performed between a heating body (a high temperature side) and a body to be heated (a low temperature side). When the heat exchange component is used in a use application in which exhaust heat is collected from an exhaust gas in a car field, the heat exchange component can be useful for improvement of a fuel efficiency of a car.

Description of Reference Numerals

1: honeycomb structure, 2: end face (in an axial direction), 2a: first end face, 2b: second end face, 3: cell, 4: partition wall, 7: circumferential wall, 7h: circumferential surface (of the honeycomb structure), 10: heat exchange member, 11: covering member, 11h: circumferential surface (of the covering member), 25: first fluid passing portion, 26: second fluid passing portion, 27: third fluid passing portion, 30: heat exchange component, 32: tubular passing portion, 32j: axial direction passing portion, 32k: peripheral direction passing portion, 33: circumferential passing portion, 40: heat exchange component, and 41: casing.

Claims

A heat exchange component comprising:
a honeycomb structure having partition walls extending through the honeycomb structure from a first end face to a second end face to define a plurality of cells forming a through channel of a first fluid, and including a ceramic material as a main component;

a covering member made of a metal and fitted into a circumference of the honeycomb structure;

a second fluid passing portion disposed to come in contact with a circumference of the covering member and forming a through channel of a second fluid; and

a third fluid passing portion disposed in a circumference of the second fluid passing portion, containing the second fluid passing portion and forming a through channel through which a third fluid is passed to come in contact with the second fluid passing portion and the covering member.
The heat exchange component according to claim 1,
wherein the second fluid passing portion is a tubular passing portion, and the tubular passing portion is wound around the circumference of the covering member to come in contact with the circumference and is spirally disposed.
The heat exchange component according to claim 1,
wherein the second fluid passing portion is a tubular passing portion, and the tubular passing portion is disposed to come in contact with the circumference of the covering member in a meandering manner.
The heat exchange component according to claim 1,
wherein the second fluid passing portion is disposed to come in contact with the circumference of the covering member in a lattice manner.
The heat exchange component according to any one of claims 1 to 4,
wherein (a contact area between the second fluid passing portion and the covering member)/(a circumferential surface area of the honeycomb structure) is from 0.01 to 0.3.
The heat exchange component according to any one of claims 1 to 5,
wherein (a contact surface area of the second fluid passing portion which comes in contact with the third fluid)/(a volume of the second fluid passing portion) is from 0.3 to 0.8.
The heat exchange component according to any one of claims 1 to 6,
wherein a distance between a tubular passing portion and the adjacent tubular passing portion forming the second fluid passing portion is from 0.3 to 7.0 mm.