JP2018100596A - Exhaust gas warming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust gas warming device capable of efficiently warming an exhaust emission control member.SOLUTION: This invention relates to an exhaust gas warming device provided in an exhaust gas pipe line of an internal combustion engine. The exhaust gas warming device includes an exhaust emission control member and an exhaust gas warming member. The exhaust emission control member modifies or collects environmental pollutants in exhaust gas. The exhaust gas warming member warms the exhaust gas. At least part of the exhaust gas warming member is embedded in the exhaust emission control member in a flowing direction of the exhaust gas. A filling material is filled in part of an air gap between the embedded portion of the exhaust gas warming member and the exhaust emission control member.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an exhaust gas heating device.

  In order to comply with regulations regarding exhaust gas components of an internal combustion engine, an exhaust gas purification device is often installed in the exhaust gas pipeline of the internal combustion engine. For example, in the case of a diesel engine, an exhaust gas purification member such as a diesel oxidation catalyst (DOC), a diesel particulate filter (DPF), and a selective catalyst reduction (SCR) catalyst is used for the exhaust gas purification device.

  Such an exhaust gas purification member requires a certain temperature in order to reform or collect environmental pollutants. On the other hand, the exhaust gas temperature varies according to the operating state of the internal combustion engine. In particular, the exhaust gas temperature is low during cold start or deceleration. Therefore, the exhaust gas purification member may not function sufficiently.

  In view of this, a technique has been proposed in which an electric heating element is arranged upstream of the exhaust gas purification member to heat the exhaust gas, thereby increasing the temperature of the exhaust gas purification member (see Patent Document 1).

Japanese Patent Laying-Open No. 2015-033911

  When the exhaust gas heating member is installed on the upstream side of the exhaust gas purification member as in Patent Document 1, heat transfer or heat conduction to the metal pipe constituting the exhaust gas pipe line occurs. Due to such heat radiation to the outside, the heating efficiency of the exhaust gas, and hence the exhaust gas purification member, is lowered. As a result, energy such as electric power consumed by the exhaust gas heating member increases, and the fuel consumption of the internal combustion engine deteriorates.

  An object of one aspect of the present disclosure is to provide an exhaust gas heating device that can efficiently heat an exhaust gas purification member.

  One aspect of the present disclosure is an exhaust gas heating device provided in an exhaust gas pipe of an internal combustion engine. The exhaust gas heating device includes an exhaust gas purification member and an exhaust gas heating member. The exhaust gas purification member reforms or collects environmental pollutants in the exhaust gas. The exhaust gas heating member warms the exhaust gas. At least a part of the exhaust gas heating member is embedded in the exhaust gas purification member in the exhaust gas flow direction. At least a part of the gap between the embedded portion of the exhaust gas heating member and the exhaust gas purification member is filled with a filler.

  According to such a configuration, since the exhaust gas heating member is embedded in the exhaust gas purification member, heat outflow from the heated exhaust gas to the surrounding piping can be suppressed. Further, since the space between the exhaust gas heating member and the exhaust gas purification member is filled with the filler, the amount of heat carried downstream by the exhaust gas passing between these members, that is, the heating of the exhaust gas purification member is contributed. The amount of heat not to be reduced can be reduced. As a result, the exhaust gas purification member can be efficiently heated and the fuel consumption can be reduced.

  In one embodiment of the present disclosure, the entire space may be filled with a filler as viewed from the flow direction of the exhaust gas. According to such a structure, it can suppress that exhaust gas flows between an exhaust-gas heating member and an exhaust-gas purification member, and flows downstream. Therefore, the exhaust gas purification member can be heated more efficiently.

  In one embodiment of the present disclosure, at least a most upstream portion in the flow direction of the exhaust gas in the gap may be sealed with a filler. According to such a configuration, the exhaust gas that has entered between the exhaust gas heating member and the exhaust gas purification member moves upstream after colliding with the filler, and transfers heat to the upstream piping. It is suppressed. As a result, the exhaust gas purification member can be heated more efficiently.

  In one aspect of the present disclosure, in the exhaust gas heating member, an upstream end in the exhaust gas flow direction may be covered with a filler. According to such a structure, it is suppressed that the exhaust gas which contact | connected the exposed part of the upstream of an exhaust gas heating member conveys heat to piping. As a result, the exhaust gas purification member can be heated more efficiently.

  In one embodiment of the present disclosure, at least the most downstream portion in the flow direction of the exhaust gas in the gap may be sealed with a filler. According to such a configuration, the exhaust gas caught between the exhaust gas heating member and the exhaust gas purification member from the downstream side is prevented from moving downstream and transferring heat to the downstream piping. . As a result, the exhaust gas purification member can be heated more efficiently.

  In one aspect of the present disclosure, in the exhaust gas heating member, an end portion on the downstream side in the exhaust gas flow direction may be covered with a filler. According to such a configuration, the exhaust gas in contact with the exposed portion on the downstream side of the exhaust gas heating member is suppressed from transferring heat to the pipe. As a result, the exhaust gas purification member can be heated more efficiently.

  In one aspect of the present disclosure, the filler may include at least a part of a material constituting the exhaust gas purification member. According to such a configuration, the difference in thermal expansion between the exhaust gas purification member and the filler can be reduced. As a result, distortion of the device due to heating can be suppressed.

  In one aspect of the present disclosure, the exhaust gas purification member may be based on a non-conductive material. According to such a structure, the effort which insulates an exhaust-gas purification member and an exhaust-gas heating member can be saved.

  In one aspect of the present disclosure, the internal combustion engine may be a diesel engine. Further, the exhaust gas purification member may be a diesel oxidation catalyst, a diesel particulate filter, a selective catalyst reduction catalyst, or a combination of these. According to such a structure, the fuel consumption of a diesel engine provided with an exhaust gas purification device can be improved.

It is typical sectional drawing which shows the exhaust gas heating apparatus of embodiment. It is a typical perspective view which shows the exhaust-gas purification member of the exhaust-gas heating apparatus of FIG. 3A is a schematic front view showing the arrangement of the exhaust gas heating member of the exhaust gas heating apparatus of FIG. 1, and FIG. 3B is a schematic view showing the arrangement of the exhaust gas heating member different from FIG. 3A. 3C is a front view, and FIG. 3C is a schematic front view showing an arrangement of the exhaust gas heating member different from FIGS. 3A and 3B. It is a typical fragmentary sectional view explaining transmission of the heat from an exhaust-gas heating member in case there is no filler. FIG. 5A is a schematic partial cross-sectional view showing an exhaust gas heating apparatus according to an embodiment different from FIG. 1, and FIG. 5B shows an exhaust gas heating apparatus according to an embodiment different from FIGS. FIG. 5C is a schematic partial cross-sectional view, FIG. 5C is a schematic partial cross-sectional view showing an exhaust gas heating apparatus according to an embodiment different from FIGS. 1, 5A and 5B, and FIG. FIG. 5A is a schematic partial cross-sectional view showing an exhaust gas heating apparatus according to an embodiment different from those shown in FIGS. 5A, 5B, and 5C. It is typical sectional drawing which shows the exhaust gas heating apparatus of embodiment different from FIG.

Hereinafter, embodiments to which the present disclosure is applied will be described with reference to the drawings.
[1. First Embodiment]
[1-1. Constitution]
An exhaust gas heating device (hereinafter, also simply referred to as “heating device”) 1 shown in FIG. 1 is provided in an exhaust gas pipe 100 of an internal combustion engine. The heating device 1 includes an exhaust gas purification member 2 and an exhaust gas heating member 3, and removes environmental pollutants in the exhaust gas G.

  The internal combustion engine provided with the warming device 1 is not particularly limited, but the warming device 1 can be particularly preferably used for the exhaust gas discharged from the diesel engine. Examples of diesel engines include those used for driving or power generation in transportation equipment such as automobiles, railways, ships, construction machinery, and power generation facilities.

(Exhaust gas purification member)
The exhaust gas purification member 2 is a member that modifies or collects environmental pollutants in the exhaust gas G. Here, the “environmental pollutant” means carbon monoxide (CO), nitrogen oxide (NOx), particulate matter (PM), sulfur oxide (SOx), hydrocarbons (HC), and the like.

  Specific examples of the exhaust gas purification member 2 include, for example, a diesel oxidation catalyst (DOC), a diesel particulate filter (DPF), a selective catalyst reduction (SCR) catalyst, and the like. DOC is a catalyst that oxidizes soluble organic components (SOF), CO, and HC in PM contained in exhaust gas. The DPF is a filter that collects PM contained in exhaust gas. SCR is a technology that reduces NOx to nitrogen.

  Further, the exhaust gas purification member 2 may be a composite of two or more of DOC, DPF and SCR catalyst. For example, it is assumed that the exhaust gas purification member 2 is used as a composite catalyst that serves as both a DPF and an SCR catalyst.

  As shown in FIG. 2, the exhaust gas purification member 2 is a cylindrical body having a honeycomb structure. When the exhaust gas passes through the inside of the honeycomb structure, the environmental pollutant in the exhaust gas is modified by the catalytic metal included in the exhaust gas purification member 2 or is captured on the surface of the exhaust gas purification member 2.

  The material of the exhaust gas purification member 2 is appropriately selected depending on its function. The exhaust gas purification member 2 used as a catalyst is composed of a catalyst metal having a catalytic function and a base material supporting the catalyst metal. On the other hand, the exhaust gas purification member 2 used as a filter is usually composed of only a base material. However, when the functions of the catalyst are combined as described above, the catalyst metal is supported by the base material.

  The base material of the exhaust gas purification member 2 is appropriately selected depending on the required function. Examples of the base material include ceramic, silicon carbide (SIC), stainless steel, and the like. Similarly, the catalyst metal is appropriately selected depending on the function. Examples of the catalyst metal include platinum (Pt) and palladium (Pd).

Further, as the base material of the exhaust gas purification member 2, a non-conductive material is preferable. By making the base material of the exhaust gas purification member 2 nonconductive, it is not necessary to insulate the exhaust gas purification member 2 and the exhaust gas heating member 3 when the exhaust gas heating member 3 is an electric heater or the like. Therefore, it is possible to reduce the cost of the insulating member and the labor of arrangement. “Non-conductive material” means a material having an electrical resistivity of 1 × 10 ⁻⁴ Ωm or more.

  The exhaust gas purification member 2 has one or more through holes for embedding the exhaust gas heating member 3. The one or more through holes are formed so as to penetrate the exhaust gas purification member 2 in the exhaust gas flow direction.

(Exhaust gas heating member)
The exhaust gas heating member 3 is a member that indirectly heats the exhaust gas purification member 2 by heating the exhaust gas. The exhaust gas heating member 3 is not particularly limited as long as the exhaust gas can be heated, and for example, an electrothermal heater can be adopted.

  The shape of the exhaust gas heating member 3 is not particularly limited. The exhaust gas heating member 3 may be a member in which a plurality of rod-like bodies as shown in FIG. 3A are arranged at regular intervals, for example. Further, the exhaust gas heating member 3 may be a single plate-like body curved in a bellows shape as shown in FIG. 3B. Further, the exhaust gas heating member 3 may be a cylindrical body arranged so as to surround the exhaust gas purification member 2 as shown in FIG. 3C.

  In the present embodiment, the exhaust gas heating member 3 is entirely embedded in the exhaust gas purification member 2 as shown in FIG. That is, the exhaust gas heating member 3 is inserted so as to be accommodated in the through hole of the exhaust gas purification member 2. Further, the upstream end and the downstream end of the exhaust gas heating member 3 in the exhaust gas flow direction are both located on the inner side of the upstream end and the downstream end of the exhaust gas purification member 2.

(Filler)
The filler 4 is filled in a gap between the embedded portion of the exhaust gas heating member 3 and the exhaust gas purification member 2 and seals the gap. In the present embodiment, as shown in FIGS. 3A, 3B, and 3C, the entire space is sealed with the filler 4 when viewed from the flow direction of the exhaust gas. That is, the entire periphery of the exhaust gas heating member 3 is sealed in the flow direction of the exhaust gas.

  Further, as shown in FIG. 1, among the gaps between the embedded portion of the exhaust gas heating member 3 and the exhaust gas purification member 2, the most upstream portion and the most downstream portion in the exhaust gas flow direction are at least a filler 4. It is sealed by. Note that the gap between the most upstream part and the most downstream part is not sealed.

  Further, in the present embodiment, the upstream end portion and the downstream end portion of the exhaust gas heating member 3 in the exhaust gas flow direction are respectively covered with the filler 4. That is, both end surfaces of the exhaust gas heating member 3 are covered with the filler 4.

  The material of the filler 4 is not particularly limited as long as the exhaust gas can be prevented from passing therethrough. However, from the viewpoint of reducing the difference in thermal expansion between the exhaust gas purification member 2 and the filler 4, the filler 4 may include at least a part of the material (particularly the base material) constituting the exhaust gas purification member 2. . By reducing the difference in thermal expansion between the exhaust gas purification member 2 and the filler 4, distortion of the device caused by heating can be suppressed.

  Here, the effect | action of the filler 4 of the heating apparatus 1 is demonstrated using FIG. In addition, the arrow in FIG. 4 shows the movement of heat. As shown in FIG. 4, when the filler 4 is not present, the exhaust gas passes through the gap between the exhaust gas purification member 2 and the exhaust gas heating member 3. As a result, a part of the heat generated by the exhaust gas heating member 3 is carried downstream by the exhaust gas as indicated by the arrow in the figure, resulting in a heat loss.

  On the other hand, when the filler 4 exists between the exhaust gas purification member 2 and the exhaust gas heating member 3 as shown in FIG. 1, the passage of the exhaust gas is blocked, so that heat loss to the downstream is suppressed. It is done. In particular, in the present embodiment, since the filler 4 is present in the most upstream portion of the gap, the passage of exhaust gas can be almost eliminated. Furthermore, in this embodiment, since the filler 4 exists also in the most downstream part of a space | gap, it is suppressed that exhaust gas is drawn into a space | gap from a downstream and takes heat away.

[1-2. Production method]
The heating device 1 includes a step of producing the exhaust gas purification member 2, a step of forming a hole for embedding the exhaust gas heating member 3 in the exhaust gas purification member 2, and an exhaust gas warming in the exhaust gas purification member 2. It can be obtained by a manufacturing method including a step of embedding the member 3 and a step of filling the gap 4 with the filler 4.

<Exhaust gas purification member manufacturing process>
In this step, the exhaust gas purification member 2 is produced. As a specific method, for example, a method of extruding the base material of the exhaust gas purification member 2 and firing the obtained molded product can be employed. When the exhaust gas purification member 2 is a catalyst, the metal catalyst is supported after the base material is fired.

<Hole formation process>
In this step, a through hole is formed in the exhaust gas purification member 2. The through hole can be formed by cutting, for example.

<Embedding process>
In this step, the exhaust gas purification member 2 is inserted and embedded in the through hole of the exhaust gas purification member 2. The exhaust gas heating member 3 is fixed in the through hole by the filler 4 in the next filling step.

<Filling process>
In this step, the filler 4 is disposed in the gap between the exhaust gas purification member 2 and the exhaust gas heating member 3. Specifically, for example, the filler 4 is applied into the gap with a dispenser or the like, and then baked to fill the gap with the filler 4. The firing temperature of the filler 4 needs to be equal to or lower than the boiling point of the metal catalyst carried by the exhaust gas purification member 2.

[1-3. effect]
According to the embodiment detailed above, the following effects can be obtained.
(1a) Since the exhaust gas heating member 3 is embedded in the exhaust gas purification member 2, heat outflow from the heated exhaust gas to the surrounding piping can be suppressed. In particular, in this embodiment, since the exhaust gas heating member 3 is entirely embedded in the exhaust gas purification member 2, the heat outflow suppression effect is high. Therefore, the exhaust gas purification member 2 can be efficiently heated, and the fuel consumption can be reduced.

  (1b) Since the space between the exhaust gas heating member 3 and the exhaust gas purification member 2 is sealed with the filler 4, it is carried downstream by the exhaust gas and consequently does not contribute to the heating of the exhaust gas purification member 2. The amount of heat can be reduced. Therefore, the exhaust gas purification member 2 can be efficiently heated, and the fuel consumption can be reduced.

  (1c) Since the entire gap between the exhaust gas heating member 3 and the exhaust gas purification member 2 is sealed when viewed from the flow direction of the exhaust gas, the exhaust gas is exhausted from the exhaust gas heating member 3 and the exhaust gas. Passing between the gas purification member 2 and flowing downstream can be reliably suppressed.

  (1d) Of the gap between the exhaust gas heating member 3 and the exhaust gas purification member 2, the most upstream portion and the most downstream portion in the exhaust gas flow direction are sealed. Therefore, it can be suppressed that the exhaust gas moves from the gap to the upstream side and transfers heat to the pipe, and that the exhaust gas caught in the gap from the downstream side moves again downstream and transfers the heat to the pipe.

  (1e) Since the exhaust gas warming member 3 is covered with the filler 4 at the upstream end and the downstream end in the flow direction of the exhaust gas, the upstream side and the downstream side of the exhaust gas warming member 3 Exhaust gas in contact with the exposed portion on the side can be prevented from transferring heat to the pipe.

[2. Other Embodiments]
As mentioned above, although embodiment of this indication was described, it cannot be overemphasized that this indication can take various forms, without being limited to the above-mentioned embodiment.

  (2a) In the heating device 1 of the above-described embodiment, the gap between the exhaust gas heating member 3 and the exhaust gas purification member 2 is not necessarily filled with the filler 4 as viewed from the exhaust gas flow direction. May be. That is, as in the heating device 1A shown in FIG. 5A, it is only necessary that at least a part of the gap viewed from the exhaust gas flow direction is filled with the filler 4.

  (2b) Further, even when the entire gap viewed from the flow direction of the exhaust gas is sealed, as in the heating device 1B shown in FIG. 5B, one or a plurality of fillers 4 are arranged in the flow direction of the exhaust gas. You may arrange | position in a different position. However, as shown by an arrow in FIG. 5B, if the filler 4 is disposed near the center in the exhaust gas flow direction, heat is transferred to the upstream pipe by the exhaust gas rebounding from the filler 4. For this reason, at least the most upstream part of the gap may be sealed as in the heating device 1C of FIG. 5C.

  Furthermore, when only the uppermost stream portion of the gap is sealed as in the heating device 1C shown in FIG. 5C, heat loss occurs due to the exhaust gas that is drawn in from the downstream side and flows downstream again as indicated by the arrows. Cheap. Therefore, it is better to seal the most downstream part together with the most upstream part of the gap as in the heating device 1 of FIG. In addition, what sealed only the most downstream part of the space | gap is also in the range which this indication intends.

  (2c) In the heating device 1 of the above embodiment, the upstream end and the downstream end of the exhaust gas heating member 3 do not necessarily have to be covered with the filler 4. That is, as in the heating device 1D shown in FIG. 5D, the end of the exhaust gas heating member 3 may be exposed. Alternatively, only one of the upstream end and the downstream end of the exhaust gas heating member 3 may be covered.

  (2d) In the heating device 1 of the above embodiment, the exhaust gas heating member 3 does not have to be entirely embedded in the exhaust gas purification member 2. That is, the exhaust gas heating member 3 may have an upstream end or a downstream end in the exhaust gas flow direction protruding beyond the end surface of the exhaust gas purification member 2. In this case, the portion protruding from the end face of the exhaust gas purification member 2 may be covered with the filler 4.

  (2e) In the heating device 1 of the above embodiment, the hole for embedding the exhaust gas heating member 3 may not be a through hole. That is, the exhaust gas heating member 3 may be embedded in a bottomed cylindrical hole having a bottom at one end.

  (2f) A second exhaust gas purification member in which the exhaust gas heating member 3 is not embedded downstream of the exhaust gas purification member 2 in which the exhaust gas heating member 3 is embedded, as in the heating device 1E shown in FIG. 12 may be arranged. The reaction area of the exhaust gas purification member 2 is reduced by embedding the exhaust gas heating member 3. Therefore, the deterioration of the purification function can be compensated by additionally installing the second exhaust gas purification member 12 on the downstream side.

  (2g) The functions of one constituent element in the above embodiment may be distributed as a plurality of constituent elements, or the functions of a plurality of constituent elements may be integrated into one constituent element. Moreover, you may abbreviate | omit a part of structure of the said embodiment. In addition, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of the other embodiment. In addition, all the aspects included in the technical idea specified from the wording described in the claims are embodiments of the present disclosure.

1, 1A, 1B, 1C, 1D, 1E ... heating device, 2 ... exhaust gas purification member,
3 ... exhaust gas heating member, 4 ... filler, 12 ... second exhaust gas purification member,
100: exhaust gas line, G: exhaust gas.

Claims (9)

An exhaust gas heating device provided in an exhaust gas pipe of an internal combustion engine,
An exhaust gas purification member for reforming or collecting environmental pollutants in the exhaust gas;
An exhaust gas heating member for heating the exhaust gas,
At least a part of the exhaust gas heating member is embedded in the exhaust gas purification member in the exhaust gas flow direction,
An exhaust gas heating apparatus, wherein a filler is filled in at least a part of a gap between the embedded portion of the exhaust gas heating member and the exhaust gas purification member.   The exhaust gas heating apparatus according to claim 1, wherein the filler is filled in the entire space as viewed from the flow direction of the exhaust gas.   3. The exhaust gas heating device according to claim 1, wherein at least a most upstream portion of the gap in a flow direction of the exhaust gas is sealed with the filler.   The exhaust gas warming device according to claim 3, wherein the exhaust gas warming member is coated with the filler at an upstream end in a flow direction of the exhaust gas.   The exhaust gas heating device according to any one of claims 1 to 4, wherein at least a most downstream portion of the gap in the flow direction of the exhaust gas is sealed with the filler.   The exhaust gas warming device according to claim 5, wherein the exhaust gas warming member is covered with the filler at a downstream end in a flow direction of the exhaust gas.   The exhaust gas heating device according to any one of claims 1 to 6, wherein the filler includes at least a part of a material constituting the exhaust gas purification member.   The exhaust gas heating device according to any one of claims 1 to 7, wherein the exhaust gas purification member uses a non-conductive material as a base material. The internal combustion engine is a diesel engine;
The exhaust gas purification member according to any one of claims 1 to 8, wherein the exhaust gas purification member is a diesel oxidation catalyst, a diesel particulate filter, a selective catalyst reduction catalyst, or a combination thereof. Temperature device.

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