JP2018031262A - Warming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for effectively utilizing heat released from a gas warming member.SOLUTION: A warming device includes a gas flow path member for distributing exhaust gas flowing in an exhaust passage, the gas warming member arranged in the gas flow path member and having a first gas flow path for distributing the exhaust gas from the upstream side to the downstream side of the gas flow path member, and a heat recovery member arranged between the gas warming member and the gas flow path member so as to encircle the outer periphery of the gas warming member, for recovering heat from the gas warming member, the heat recovery member having a second gas flow path for distributing the exhaust gas from the upstream side to the downstream side.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a technique for heating exhaust gas.

  2. Description of the Related Art In recent years, various exhaust gas purifying devices are arranged in the middle of an exhaust passage of an internal combustion engine (for example, Patent Document 1). Examples of these exhaust gas purification devices include a selective reduction catalyst (SCR) device for reducing and purifying NOx and a diesel particulate filter (DPF) for collecting particulate matter (PM). Many of these exhaust gas purification apparatuses have a high activation temperature (for example, 180 degrees or more). Therefore, in the conventional technology, a gas heating member (for example, a regenerator or a heater) is provided in the middle of the exhaust passage. The gas heating member warms the exhaust gas to the activation temperature.

JP 2008-190462 A

  In the prior art, as disclosed in Patent Document 1, for example, an exhaust gas pipe without a gas heating member disposed around an exhaust gas pipe (heating pipe) having a gas heating member arranged therein. The gas heating member has a double structure by covering with (bypass pipe). Thereby, the heat from the gas heating member and the heat from the exhaust gas in the bypass pipe are recovered. However, in the conventional technology, no member for heat recovery is installed around the gas heating member (for example, in the heating pipe) having a large amount of heat radiation to the outside. Therefore, the problem that the heat from a gas heating member cannot be collected effectively may arise. Further, according to the conventional technique, exhaust gas having a temperature lower than that of the gas heating member flows through the bypass pipe arranged around the heating pipe, so that the heat of the gas heating member is increased. Thereby, the electric power required for heating the gas heating member to the target temperature is increased, which may cause a problem that fuel consumption deteriorates. Therefore, conventionally, a technique that can effectively use the heat released from the gas heating member is desired.

  The present invention has been made to solve the above-described problems, and can be realized as the following forms or application examples.

(1) According to one aspect of the present invention, there is provided a heating device that is provided in the middle of an exhaust passage of an internal combustion engine and that warms exhaust gas flowing through the exhaust passage. The heating device includes a gas flow path member for circulating the exhaust gas flowing through the exhaust flow path, and an upstream side of the gas flow path member disposed in the gas flow path member from the downstream side. A gas heating member having a first gas flow path for circulating the exhaust gas, and disposed between the gas heating member and the gas flow path member so as to surround an outer peripheral portion of the gas heating member. A heat recovery member for recovering heat from the gas heating member, wherein the heat recovery member is a second gas flow for circulating the exhaust gas from the upstream side to the downstream side. Has a road. According to this aspect, heat can be stored in the heat recovery member by recovering the heat released from the gas heating member by the heat recovery member. Accordingly, the exhaust gas flowing through the gas flow path member can be heated by the heat stored in the heat recovery member in addition to the heat of the gas heating member. Therefore, the exhaust gas can be heated by effectively utilizing the heat released from the gas heating member.

(2) It is the said form, Comprising: The said heat recovery member may be arrange | positioned so that the clearance gap between the said outer peripheral part of the said gas heating member and the said gas flow path member may be filled up. According to this aspect, the heat recovery member can store heat also by heat conduction from the outer peripheral portion of the gas heating member. Thereby, the heat released from the gas heating member can be used more effectively. Further, when the exhaust gas passes through the gas channel member, the exhaust gas passes through the first gas channel or the second gas channel, so that the exhaust gas can be efficiently heated.

(3) It is the said form, Comprising: The pressure loss of the said 2nd gas flow path may be more than the pressure loss of the said 1st gas flow path. According to this aspect, when exhaust gas is circulated through the flow path of the gas flow path member, the possibility that the amount of exhaust gas flowing through the first gas flow path is reduced can be reduced. Thereby, exhaust gas can be efficiently heated by the heat of a gas heating member.

(4) In the above embodiment, the heat recovery member may be longer than the gas heating member in the flow direction of the exhaust gas. According to this aspect, more of the heat released from the gas heating member can be recovered by the heat recovery member.

(5) It is the said form, Comprising: The heat conductivity of the said heat recovery member may be below the heat conductivity of the said gas flow path member. According to this embodiment, it is possible to suppress the heat released from the gas heating member and stored in the heat recovery member from moving to the gas flow path member due to heat conduction. Therefore, the heat released from the gas heating member can be used more effectively for heating the exhaust gas.

(6) In the above embodiment, the second gas flow path may have a honeycomb shape. According to this aspect, the strength of the heat recovery member forming the second gas flow path can be improved, and the exhaust gas can be made to flow uniformly throughout the second gas flow path.

(7) In the above form, the heat recovery member may contain at least one of Si, Mg, Al, C, or an oxide of Si, an oxide of Mg, and an oxide of Al. . According to this aspect, the heat recovery member can be made of a material containing at least one of Si, Mg, Al, C, or an oxide of Si, an oxide of Mg, and an oxide of Al.

(8) In the above-described form, further, a bypass channel member for circulating the exhaust gas flowing through the exhaust channel, wherein the bypass forms a channel different from the channel of the gas channel member A flow path member, a branch portion located upstream of the gas flow path member and the bypass flow path member, and branching the flow path of the gas flow path member and the flow path of the bypass flow path member; A merging portion located downstream of the gas flow path member and the bypass flow path member, where the flow path of the gas flow path member and the flow path of the bypass flow path member merge, and circulation of the exhaust gas You may provide the flow path switching part which can switch a path | route to either the said flow path of the said gas flow path member, or the said flow path of the said bypass flow path member. According to this aspect, the flow path switching unit can switch the flow path of the exhaust gas to either the flow path of the gas flow path member or the flow path of the bypass flow path member.

  The present invention can be realized in various forms, and can be realized in a mode such as a heating method, a heating device control method, and a heating device control program in addition to the heating device. it can.

It is explanatory drawing which shows roughly a vehicle provided with the heating apparatus as 1st Embodiment. It is a figure for demonstrating schematic structure of a heating apparatus. It is F2-F2 sectional drawing of FIG. It is a figure for demonstrating the heating apparatus of 2nd Embodiment. It is a figure for demonstrating the modification about arrangement | positioning of a heat recovery member.

A. First embodiment:
FIG. 1 is an explanatory diagram schematically showing a vehicle 500 including a heating device 20 as a first embodiment of the present invention. The heating device 20 is a component of the heating control device 60. In addition to the heating device 20, the heating control device 60 includes a control unit 40 for controlling the operation of the heating device 20 and the liquid supply unit 18 described later.

  The vehicle 500 includes a diesel engine (hereinafter referred to as “engine”) 510 as an internal combustion engine, four wheels 520, and the exhaust gas purification system 10. The heating control device 60 is provided in the exhaust gas purification system 10. The engine 510 uses light oil as fuel, and outputs driving force by explosive combustion of the fuel. Exhaust gas containing NOx (nitrogen oxide) and PM (particulate matter) accompanying the explosion combustion is discharged to the atmosphere through an exhaust gas purification system 10 provided in the exhaust system. Note that the vehicle configuration shown in FIG. 1 used in the first embodiment can be used in other embodiments as well.

  The exhaust gas purification system 10 includes various exhaust gas purification devices that are provided in the middle of the exhaust flow path (exhaust pipe) 11 and constitute a part of the exhaust flow path 11. The exhaust passage 11 is connected to the engine 510 via the manifold 11a on the engine 510 side (upstream side of the exhaust gas flow). The exhaust passage 11 has a muffler end pipe 11b disposed on the most downstream side of the exhaust gas flow. In this specification, “upstream side” and “downstream side” are based on the flow direction of the exhaust gas flowing through the exhaust passage 11.

The exhaust gas purification system 10 includes a diesel oxidation catalyst (DOC) 12, a diesel particulate filter (DPF) 13, a heating device 20, a selective reduction catalyst (SCR) device 14, an ammonia slip diesel, in order from the upstream side. Oxidation catalyst (NH ₃ DOC) 15. Each of the various exhaust gas purifying devices 12, 13, 20, 14, 15 is provided in the middle of the exhaust passage 11. A fuel injection device 17 is disposed upstream of the DOC 12 in the exhaust passage 11. A temperature sensor 192 for detecting the temperature on the downstream side in the DPF 13 is disposed in the DPF 13.

The DOC 12 supports a noble metal such as platinum (Pt) or palladium (Pd) as a catalyst. The DOC 12 oxidizes carbon monoxide (CO) and hydrocarbons (HC), which are unburned gas components contained in the exhaust gas, and converts them into carbon dioxide (CO ₂ ) and water (H ₂ O). Then, nitric oxide (NO) contained in the exhaust gas is oxidized and converted to nitrogen dioxide (NO ₂ ).

The DPF 13 is a filter that collects particulate matter (PM) contained in the exhaust gas through a fine gap between porous ceramics or metal. A metal catalyst such as platinum is applied to the surface of the filter. The DPF 13 is converted into carbon dioxide (CO ₂ ) and water (H ₂ O) in the presence of NOx produced by the DOC 12 by causing the particulate matter to chemically react with the catalyst in an atmosphere of 250 to 300 degrees. It is naturally regenerated. The DPF 13 supplies fuel to the DOC 12 directly from the engine 510 via the fuel injection device 17 or through an exhaust stroke, and captures the exhaust temperature at 450 degrees or more by catalytically burning fuel-derived hydrocarbons. It can also be regenerated by forced regeneration which oxidizes the particulate matter formed.

In addition to the type in which particulate matter is physically collected and the particulate matter is oxidized by catalytic combustion of hydrocarbons, the DPF 13 generates low-temperature plasma in the plasma generator and activates mainly O _3. A plasma DPF that generates seeds, supplies the generated active species to the DPF 13, and converts (oxidizes) particulate matter components such as HC and C into H ₂ O and CO ₂ may be used. In the plasma DPF, the particulate matter can be oxidized without using fuel, but the particulate matter is not collected in the physical form, so the amount of active species corresponding to the amount of the particulate matter to be processed in advance. Therefore, it is required to design a plasma generating apparatus so as to be able to generate the above.

The SCR device 14 is a device that includes a NOx reduction catalyst that carries a zeolite catalyst or a vanadium catalyst and selectively reduces NOx. In general, the SCR device 14 includes an ammonia (NH ₃ ) gas generated through a hydrolysis reaction of urea water supplied from the upstream side (previous stage) of the SCR device 14 and a NOx reduction catalyst. The NOx component of is converted to nitrogen (N ₂ ) and water (H ₂ O). Therefore, the SCR device 14 that receives the supply of urea water can obtain a desired NOx reduction function satisfactorily unless the temperature (activation temperature) for obtaining ammonia gas from the urea water, for example, a temperature of 180 ° C. or higher. Can not.

  A liquid supply unit 18 is disposed in the supply flow channel 19 between the heating device 20 and the SCR device 14 in the exhaust flow channel 11. Specifically, the liquid supply part 18 is arrange | positioned between the SCR apparatus 14 and the junction part which the heating apparatus 20 mentions later. The liquid supply unit 18 supplies urea water stored in a urea water tank (not shown) into the supply flow path 19 in accordance with an instruction from the control unit 40. The urea water contains urea and pure water as components. The liquid supply unit 18 is disposed so that the tip injection hole (supply hole) is located in the supply flow path 19. The liquid supply unit 18 realizes injection or stoppage of urea water at a high pressure by opening and closing the injection hole with an electromagnetic or piezoelectric actuator.

  The heating device 20 is disposed between the DPF 13 and the SCR device 14 in the exhaust gas flow direction. The heating device 20 has a function of heating the exhaust gas so that the NOx reduction function of the SCR device 14 can be satisfactorily exhibited. Specifically, it has a function of heating the exhaust gas to a temperature equal to or higher than the temperature for obtaining ammonia gas from the urea water supplied (injected) from the liquid supply unit 18. The generated ammonia gas is supplied to the SCR device 14 and used as a reducing agent for reducing NOx. Details of the heating device 20 and the control unit 40 included in the heating control device 60 will be described later.

NH ₃ DOC 15 carries the same catalyst as DOC 12 and oxidizes and decomposes ammonia that has not been subjected to the reaction in the SCR device 14 to generate nitrogen or NOx.

  FIG. 2 is a diagram for explaining a schematic configuration of the heating device 20. 3 is a cross-sectional view taken along line F2-F2 of FIG. The direction of the arrow YG shown in FIG. 2 indicates the flow direction of the exhaust gas. In other figures, the flow direction of the exhaust gas is indicated by the direction of the arrow YG as necessary.

  The heating device 20 (FIG. 2) includes a gas flow path member 24, a gas heating member 30, a heat recovery member 28, a bypass flow path member 25, a branching section 20A, a merging section 20B, and a flow path switching. Part 80.

  The gas flow path member 24 is a tubular member made of metal (for example, SUS304). In the present embodiment, as shown in FIG. 3, the gas flow path member 24 has a rectangular frame shape with a cross-sectional shape orthogonal to the direction in which the gas flow path member 24 extends. The gas flow path member 24 forms a flow path 21 through which the exhaust gas flowing through the exhaust flow path 11 flows. The cross-sectional shape of the gas flow path member 24 is not limited to this, and may be any other shape as long as the flow path 21 through which the exhaust gas flows can be formed. For example, the cross-sectional shape of the gas flow path member 24 may be a circular or elliptical frame shape. That is, the gas flow path member 24 may be cylindrical.

  The gas heating member 30 is used for heating the exhaust gas flowing through the flow path 21. The gas heating member 30 is disposed in the middle of the flow path 21 in the gas flow path member 24. The gas heating member 30 is a heater that heats the surroundings by radiating heat according to instructions from the control unit 40. The gas heating member 30 is a resistance heating element (heating member) that generates heat when energized. The gas heating member 30 may be a linear metal material such as a nichrome wire, a copper wire, or a tungsten wire, or a plate-like bare metal material such as a stainless steel material, a copper material, or an aluminum material. The gas heating member 30 may be a three-dimensional heater. The heater formed in a three-dimensional manner can be created by, for example, forming a disk shape by winding a metal foil (metal plate) having a plurality of through-holes having burrs (protrusions) at the periphery. . In the present embodiment, the gas heating member 30 has a spiral shape made of a plate-shaped metal material (for example, copper). The shape of the gas heating member 30 is not limited to this, and the cross section may be a frame shape or a circular shape. As shown in FIG. 3, the gas heating member 30 has a first gas flow path 32 for flowing exhaust gas from the upstream side to the downstream side of the flow path 21 of the gas flow path member 24. The first gas flow path 32 is formed by a gap between adjacent metal materials among plate-like metal materials formed in a spiral shape. The gas heating member 30 further has an outer peripheral portion 34 that faces the gas flow path member 24.

The heat recovery member 28 is a member for recovering heat generated from the gas heating member 30. That is, the heat recovery member 28 functions as a heat storage body. The heat recovery member 28 is formed of one or more materials selected from metal materials (for example, stainless steel), ceramics, mixed materials including ceramics and metals, and the like. The heat recovery member 28 may be a member containing at least one of Si, Mg, Al, C, or an oxide of Si, an oxide of Mg, and an oxide of Al. The heat recovery member 28 may be a member containing at least one of SiO ₂ , MgO ₂ , and Al ₂ O ₃ in order to increase the thermal conductivity to some extent and improve the efficiency of heat recovery. Further, the thermal conductivity (W / m · K) of the heat recovery member 28 is preferably equal to or lower than the thermal conductivity of the gas flow path member 24. By doing so, it is possible to suppress the heat released from the gas heating member 30 and stored in the heat recovery member 28 from moving to the gas flow path member 24 due to heat conduction. Therefore, the heat released from the gas heating member 30 can be effectively used for heating the exhaust gas. In addition, what is necessary is just to measure heat conductivity using a well-known heat conductivity measuring device.

  The heat recovery member 28 has a second gas passage 29 for circulating the exhaust gas from the upstream side to the downstream side. In the present embodiment, the heat recovery member 28 has a mesh structure, and the second gas flow path 29 is formed by this structure. The heat recovery member 28 has a predetermined length La (FIG. 2) along the exhaust gas flow direction. The heat recovery member 28 is disposed between the gas heating member 30 and the gas flow path member 24 so as to surround the outer peripheral portion 34 of the gas heating member 30. In the present embodiment, the heat recovery member 28 is disposed so as to fill a gap between the outer peripheral portion 34 of the gas heating member 30 and the gas flow path member 24. That is, the heat recovery member 28 is in contact with the outer peripheral portion 34 of the gas heating member 30 and the inner surface of the gas flow path member 24.

  The heat recovery member 28 is preferably longer than the gas heating member 30 in the flow direction of the exhaust gas flowing through the flow path 21. In the present embodiment, the length La of the heat recovery member 28 is longer than the length Lb of the gas heating member 30. Thereby, more of the heat released from the gas heating member 30 can be recovered by the heat recovery member 28. The flow direction of the exhaust gas flowing through the flow path 21 is a direction from the upstream end to the downstream end of the gas flow path member 24, and in FIG.

  Moreover, it is preferable that the pressure loss of the 2nd gas flow path 29 is more than the pressure loss of the 1st gas flow path. By doing so, when exhaust gas is circulated through the flow path of the gas flow path member 24, the possibility that the amount of exhaust gas flowing through the first gas flow path 32 is reduced can be reduced. Thereby, the exhaust gas can be efficiently heated by the heat of the gas heating member 30. Here, in order to make the pressure loss of the second gas flow path 29 equal to or higher than the pressure loss of the first gas flow path 32, for example, the following method may be mentioned. For example, the channel cross-sectional area of the second gas channel 29 is set to be equal to or smaller than the channel cross-sectional area of the first gas channel 32. Further, for example, a part of the flow path of the second gas flow path 29 is bent or meandered. Further, for example, the channel length of the second gas channel 29 is set to be longer than the channel length of the first gas channel 32.

  The bypass flow path member 25 (FIG. 2) distributes the exhaust gas flowing through the exhaust flow path 11. The bypass channel member 25 forms a channel (bypass channel) 22 different from the channel 21 of the gas channel member 24. Unlike the gas flow path member 24, the gas heating member 30 and the heat recovery member 28 are not arranged in the bypass flow path member 25. The bypass channel member 25 has a rectangular frame shape with a cross-sectional shape orthogonal to the direction in which the bypass channel member 25 extends. The cross-sectional shape of the bypass flow path member 25 is not limited to this, and may be any other shape as long as the flow path 22 through which the exhaust gas flows can be formed. For example, the cross-sectional shape of the bypass flow path member 25 may be a circular or elliptical frame.

  The branch portion 20 </ b> A is located upstream of the gas flow path member 24 and the bypass flow path member 25. The branch portion 20A branches the flow path 21 of the gas flow path member 24 and the bypass flow path 22 of the bypass flow path member 25. The branch portion 20A is connected to the upstream ends of the gas flow path member 24 and the bypass flow path member 25, and introduces exhaust gas flowing through the exhaust flow path 11 into the flow path 21 or the bypass flow path 22.

  The flow path switching unit 80 switches the exhaust gas flow path to either the flow path 21 of the gas flow path member 24 or the bypass flow path 22 of the bypass flow path member 25 in accordance with an instruction from the control unit 40. It is. The flow path switching unit 80 selectively closes the opening formed at the upstream end of the gas flow path member 24 and the opening formed at the upstream end of the bypass flow path member 25, thereby reducing the flow path of the exhaust gas. Switch.

The flow path switching unit 80 may use, for example, any of the following methods 1 to 3.
<Method 1>
A method of selectively switching the flow path when a plate-like valve body swings about an axis provided at one end.
<Method 2>
A system in which a flow path is selectively switched by rotating a rotary valve body having a communication path inside about one axis.
<Method 3>
A system that selectively switches the flow path when the plate-shaped valve element moves linearly.

  Examples of the actuator that drives the valve body include motors such as stepping motors, electromagnetic actuators, and fluid actuators such as air and oil. Note that the flow path may not be selectively switched, that is, not exclusively. Therefore, a method that does not selectively switch the flow channel as the flow channel switching unit 80 may be adopted. For example, the flow path switching unit 80 may be provided in each of the gas flow path member 24 and the bypass flow path member 25. In this case, the flow path switching unit 80 is configured to be able to adjust the flow path cross section of the flow path 21 of the gas flow path member 24 and the bypass flow path 22 of the bypass flow path member 25 by changing the opening of the valve body. May be.

  The junction 20B is located downstream of the gas flow path member 24 and the bypass flow path member 25, and the flow path 21 of the gas flow path member 24 and the bypass flow path 22 of the bypass flow path member 25 merge. The junction 20B discharges the exhaust gas flowing through the exhaust passage 11 toward the SCR device 14 at the subsequent stage.

  For example, the control unit 40 performs the following processing starting from the fact that the ignition switch is turned on and the engine is started. Further, the following processing ends when, for example, the ignition switch is turned OFF and the engine is stopped.

  Based on the detected temperature detected by the temperature sensor 192 (FIG. 1), the control unit 40 controls the operation of the flow path switching unit 80 to switch the flow path of the exhaust gas. Specifically, when the temperature detected by the temperature sensor 192 is 200 ° C. or higher, the control unit 40 uses the gas flow path member 24 by the flow path switching unit 80 so that the exhaust gas flow path becomes the bypass flow path member 25. Block the upstream end opening. On the other hand, when the detected temperature of the temperature sensor 192 is less than 200 degrees, the upstream end opening of the bypass flow path member 25 is closed by the flow path switching unit 80 so that the exhaust gas flow path becomes the gas flow path member 24. Further, when the exhaust gas flow path is the gas flow path member 24, the control unit 40 supplies power to the gas heating member 30 to cause the gas heating member 30 to generate heat. As a result, the exhaust gas passing through the flow path 21 of the gas flow path member 24 is raised to a temperature (for example, 200 degrees) or more that can effectively exhibit the NOx reduction function of the SCR device 14. The control unit 40 sprays urea water on the supply channel 19 at regular intervals using the liquid supply unit 18. Here, the control unit 40 may always supply power to the gas heating member 30 to cause the gas heating member 30 to generate heat, starting from the ignition switch being turned on.

  According to the said 1st Embodiment, it has the heat recovery member 28 arrange | positioned so that the outer peripheral part 34 of the gas heating member 30 may be surrounded (FIG. 2). Thereby, heat can be stored in the heat recovery member 28 by recovering the heat released from the gas heating member 30 by the heat recovery member 28. Thereby, the exhaust gas flowing through the gas flow path member 24 can be heated by the heat stored in the heat recovery member 28 in addition to the heat released from the gas heating member 30. Therefore, the exhaust gas can be heated by effectively using the heat released from the gas heating member 30. In particular, in the first embodiment, the heat recovery member 28 is disposed so as to fill a gap between the outer peripheral portion 34 of the gas heating member 30 and the gas flow path member 24. Thereby, heat is also stored in the heat recovery member 28 by heat conduction from the outer peripheral portion 34 of the gas heating member 30. Thereby, the heat released from the gas heating member 30 can be used more effectively. Further, when the exhaust gas passes through the gas passage member 24, the exhaust gas passes through the first gas passage 32 or the second gas passage 29, so that the exhaust gas can be heated efficiently.

  Further, according to the first embodiment, the flow path switching unit 80 switches the flow path of the exhaust gas to either the flow path 21 of the gas flow path member 24 or the bypass flow path 22 of the bypass flow path member 25. be able to. Thereby, based on the driving | running state of the vehicle 500, the flow path of exhaust gas can be switched to either the flow path 21 of the gas flow path member 24, or the bypass flow path 22 of the bypass flow path member 25. FIG. For example, when the temperature of the exhaust gas is less than the activation temperature at which the function of the SCR device 14 can be satisfactorily performed, the flow path switching unit 80 sets the flow path of the exhaust gas as the flow path 21 of the gas flow path member 24. Thus, the exhaust gas can be heated to the activation temperature or higher by the gas heating member 30 or the heat recovery member 28. In the present embodiment, the heating device 20 raises the exhaust gas to a temperature at which the NOx catalytic function of the SCR device 14 can be effectively exhibited. However, the heating device 20 is not limited to this, and the heating device 20 has a catalytic function. You may use for the auxiliary heating for exhibiting effectively.

B. Second embodiment:
FIG. 4 is a diagram for explaining the heating device 20a of the second embodiment. FIG. 4 corresponds to FIG. The difference between the heating device 20a and the heating device 20 of the first embodiment is the shape of the second gas flow path 29a of the heat recovery member 28a. Since the warming device 20a and the warming device 20 have the same configuration with respect to other configurations, the same configurations are denoted by the same reference numerals and description thereof is omitted. Moreover, the heating apparatus 20a has a configuration such as the bypass flow path member 25 and the flow path switching unit 80 as shown in FIG. 2 as in the first embodiment.

  The second gas channel 29a has a honeycomb shape. That is, the heat recovery member 28a is a honeycomb structure in which regular hexagonal columns are arranged without gaps. As a result, the strength of the heat recovery member 28a forming the second gas flow path 29a can be improved, and the exhaust gas can be made to flow uniformly throughout, thereby improving the efficiency of heat recovery. Note that the honeycomb shape is not limited to a regular hexagonal prism as in the present embodiment, and may be, for example, a regular quadrangular prism or a regular triangular prism. The honeycomb structure may be an aggregate having a uniform shape.

C. Variations:
In addition, this invention is not restricted to said embodiment, In the range which does not deviate from the summary, it can implement in a various aspect.

C-1. First modification:
In each of the above embodiments, the heat recovery members 28 and 28a are disposed so as to fill the gap between the outer peripheral portion 34 of the gas heating member 30 and the gas flow path member 24. However, the heat recovery members 28 and 28a are disposed. Is not limited to this. If the heat recovery members 28 and 28 a are disposed between the outer peripheral portion 34 of the gas heating member 30 and the gas flow path member 24 so as to surround the outer peripheral portion 34 of the gas heating member 30, the gas heating member 30. A gap may be formed between the outer peripheral portion 34 and the inner surface of the gas flow path member 24.

  FIG. 5 is a view for explaining a modified example of the arrangement of the heat recovery member 28a. The heat recovery member 28a is the heat recovery member 28a of the second embodiment, and the flow path direction of the second gas flow path 29a is formed in one direction (the left-right direction in FIG. 5). The gas flow path member 24 has an annular protrusion 243 that protrudes inward from the inner surface. The heat recovery member 28 a is disposed so as to contact the protruding portion 243 and the outer peripheral portion 34 of the gas heating member 30. The heat recovery member 28 a is not in contact with the inner surface of the gas flow path member 24. Even if it does in this way, there exists the same effect in the point which has the structure similar to the said each embodiment. For example, heat can be stored in the heat recovery member 28 by recovering heat released from the gas heating member 30 by the heat recovery member 28. Thereby, the exhaust gas flowing through the gas flow path member 24 can be heated by the heat stored in the heat recovery member 28 in addition to the heat released from the gas heating member 30. Therefore, the exhaust gas can be heated by effectively using the heat released from the gas heating member 30. Further, in the present modification, the gap 248 between the heat recovery member 28 a and the gas flow path member 24 is generated by the protrusion 243 and the second gas flow path 29 a extending in one direction from the upstream side to the downstream side. Can be prevented from flowing into Thereby, since it can suppress that the exhaust gas which flows through the flow path 21 passes through parts other than the 1st gas flow path 32 and the 2nd gas flow path 29a, the heat recovery member 28a and the gas heating member 30 are used. The exhaust gas can be heated efficiently.

C-2. Second modification:
In each of the above embodiments, the heating devices 20 and 20a have the flow path switching unit 80, the bypass flow path member 25, the branching section 20A, and the merging section 20B (FIG. 2), but may be omitted. Good.

C-3. Third Modification In each of the above embodiments, the heating devices 20 and 20a are disposed between the DPF 13 and the SCR device 14 (FIG. 1), but are not limited to the above. For example, the heating devices 20 and 20a may be disposed in front of the DOC 12.

  The present invention is not limited to the above-described embodiments, examples, and modifications, and can be realized with various configurations without departing from the spirit thereof. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in each embodiment described in the summary section of the invention are to solve some or all of the above-described problems, or In order to achieve part or all of the above effects, replacement or combination can be performed as appropriate. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 10 ... Exhaust gas purification system 11 ... Exhaust flow path 11a ... Manifold 11b ... Muffler end pipe 12 ... Diesel oxidation catalyst 14 ... Selective reduction catalyst apparatus 17 ... Fuel injection apparatus 18 ... Liquid supply part 19 ... Supply flow path 20, 20a ... Addition Temperature device 20A ... Branching portion 20B ... Merge portion 21 ... Channel 22 ... Bypass channel 24 ... Gas channel member 25 ... Bypass channel member 28, 28a ... Heat recovery member 29, 29a ... Second gas channel 30 ... Gas Heating member 32 ... 1st gas flow path 34 ... Outer peripheral part 40 ... Control part 60 ... Heating control apparatus 80 ... Flow path switching part 192 ... Temperature sensor 243 ... Protrusion part 248 ... Gap 500 ... Vehicle 510 ... Engine 520 ... Wheel

Claims (8)

A heating device provided in the middle of an exhaust passage of an internal combustion engine for heating exhaust gas flowing through the exhaust passage,
A gas flow path member for circulating the exhaust gas flowing through the exhaust flow path;
A gas heating member disposed in the gas flow path member and having a first gas flow path for circulating the exhaust gas from the upstream side to the downstream side of the gas flow path member;
A heat recovery member for recovering heat from the gas heating member, disposed between the gas heating member and the gas flow path member so as to surround an outer periphery of the gas heating member; Prepared,
The heating device, wherein the heat recovery member has a second gas flow path for circulating the exhaust gas from the upstream side to the downstream side. The heating device according to claim 1,
The said heat recovery member is a heating apparatus arrange | positioned so that the clearance gap between the said outer peripheral part of the said gas heating member and the said gas flow path member may be filled. The heating device according to claim 1 or 2,
The heating device, wherein the pressure loss of the second gas channel is greater than or equal to the pressure loss of the first gas channel. It is a heating apparatus as described in any one of Claim 1- Claim 3, Comprising:
The heating device, wherein the heat recovery member is longer than the gas heating member in a flow direction of the exhaust gas. It is a heating apparatus as described in any one of Claim 1- Claim 4, Comprising:
The heating device, wherein the heat recovery member has a heat conductivity equal to or less than a heat conductivity of the gas flow path member. It is a heating apparatus as described in any one of Claim 1- Claim 5, Comprising:
The heating device, wherein the second gas channel has a honeycomb shape. It is a heating apparatus as described in any one of Claim 1- Claim 6, Comprising:
The heat recovery member is a heating apparatus containing Si, Mg, Al, C, or at least one of an oxide of Si, an oxide of Mg, and an oxide of Al. The heating apparatus according to any one of claims 1 to 7, further comprising:
A bypass flow path member for circulating the exhaust gas flowing through the exhaust flow path, wherein the bypass flow path member forms a flow path different from the flow path of the gas flow path member;
A branching portion located upstream of the gas flow path member and the bypass flow path member and branching the flow path of the gas flow path member and the flow path of the bypass flow path member;
A merging portion located downstream of the gas flow path member and the bypass flow path member, where the flow path of the gas flow path member and the flow path of the bypass flow path member merge;
A heating apparatus comprising: a flow path switching unit capable of switching a flow path of the exhaust gas to one of the flow path of the gas flow path member and the flow path of the bypass flow path member.

Images