JP2014101877A - Heat storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat storage device which does not need to form a temperature control unit separately.SOLUTION: A heat storage device 8 warms up catalytic agents 4, 6 provided at an exhaust system of an internal combustion engine 2 of a vehicle and includes: a reactor 8a; an adsorber 8b; and a connection line 8c. The adsorber 8b and a part of a reducer supply device (an urea spray system 7) have a heat exchange structure (for example, a structure where a pipe 7d of an urea spray line 7b is wound around an outer peripheral surface of the adsorber 8b). The connection line 8c and an urea tank 7a have a heat exchange structure (for example, a structure where a pipe 8e of the connection line 8c is arranged in the urea tank 7a).

Description

  The present invention relates to a heat storage device for warming up a catalyst provided in an exhaust system of an internal combustion engine of a vehicle.

  The exhaust system of the vehicle is provided with a catalyst or the like in order to purify environmental pollutants (HC, CO, NOx, etc.) contained in the exhaust gas discharged from the engine. The catalyst has an optimum temperature (activation temperature) for activating the purification capacity. When starting the engine, the temperature of the exhaust gas is low, and it takes time to reach the activation temperature of the catalyst. Therefore, a device for warming up the catalyst is required in order to raise the temperature in a short time to the activation temperature of the catalyst when the temperature of the exhaust gas is low, such as when the engine is started. As this device, there is a heat storage device using reaction heat of a chemical reaction in order to reduce energy loss (fuel consumption loss) and warm up. Patent Document 1 discloses a heat storage device using reaction heat of a chemical reaction that uses ammonia as a reaction medium for the chemical reaction.

JP 2011-58678 A

  When ammonia is used as a reaction medium in a chemical reaction of a heat storage device, ammonia is moved between an adsorber that adsorbs and stores ammonia and a reactor that reacts with ammonia and a reaction material to generate heat. When ammonia is separated from the adsorbent of the adsorber, the temperature of the adsorber is lowered, so that it is difficult to supply ammonia from the adsorber to the reactor. Therefore, it is necessary to keep the temperature of the adsorber at a desired temperature. However, in the case of a conventional heat storage device, a temperature control device such as a heater is provided separately, and the temperature is adjusted by the temperature control device. When such a temperature control device is provided, power for operating the temperature control device is required, resulting in energy loss. Further, in such a heat storage device, after the engine is warmed up, ammonia that has moved to the reactor is separated from the reactor by the heat of the exhaust gas, and can be continuously used by collecting it in the adsorber. However, when ammonia is recovered, since the ammonia that has reached a high temperature flows into the adsorber, it is necessary to keep the temperature of the adsorber at a desired temperature so that the temperature of the adsorber does not become excessively high. Therefore, it is necessary to add parts to the temperature control of the adsorber. The reactor and the adsorber are connected by a pipe (connection line), and ammonia moves through this pipe. It is also conceivable to cool the ammonia by adjusting the temperature of the pipe when high temperature ammonia flows in the pipe. In this case, however, it is necessary to add a part for adjusting the temperature of the pipe.

  Then, this invention makes it a subject to provide the thermal storage apparatus which does not need to provide a temperature control apparatus separately.

  A heat storage device according to the present invention is a heat storage device that warms up at least a part of an exhaust system of an internal combustion engine of a vehicle, and is a reaction that is disposed in the exhaust system and has a reaction material that chemically reacts with ammonia to generate heat. And a reduction line for supplying a reducing agent to the selective reduction catalyst and the selective reduction catalyst in the exhaust system, and a connection line connecting the reactor and the adsorber. An agent supply device is provided at least, and the adsorber or the connection line and a part of the reducing agent supply device have a heat exchange structure.

  2. Description of the Related Art An exhaust system for an internal combustion engine of a vehicle includes a heat storage device that quickly raises the temperature of the exhaust system such as when starting the internal combustion engine when the temperature is low. This heat storage device moves ammonia between a reactor in which ammonia and a reaction material chemically generate heat, an adsorber that adsorbs and stores ammonia with an adsorbent, and the reactor and the adsorber. A connection line is provided. In particular, the exhaust system is provided with a selective reduction catalyst, and there is a reducing agent supply device for supplying a reducing agent to the selective reduction catalyst. A reducing agent supply device generally supplies a reducing agent stored at room temperature. A part of the reducing agent supply device (for example, a reducing agent supply line, a reducing agent tank) and an adsorber or a connection line exchange heat. By having such a heat exchange structure, the temperature of the adsorber or the connection line is adjusted by heat exchange with a part of the reducing agent supply device. By this temperature control, the adsorber can be directly heated or cooled, or the temperature of the adsorber can be maintained at a desired temperature by cooling high-temperature ammonia flowing into the adsorber through the connection line. Thus, in this heat storage device, a reducing agent supply device that supplies a reducing agent to the selective reduction catalyst provided in the exhaust system is used, and a part of the reducing agent supply device and the adsorber or the connection line are combined with a heat exchange structure. By doing so, it is possible to adjust the temperature of the adsorber and the connection line without separately providing a temperature control device. As a result, power for operating the temperature control device is not required, energy loss can be reduced, and the cost of separately providing the temperature control device is not required. Moreover, warming up of a catalyst etc. can be performed in a short time. It should be noted that the case where the temperature of the adsorber and the connecting line are controlled together in each part of the reducing agent supply device is also included.

  In the heat storage device of the present invention, it is preferable that the adsorber and a part of the reducing agent supply device have a heat exchange structure.

  By having such a heat exchange structure, in the adsorber, the temperature is adjusted by heat exchange with a part of the reducing agent supply device. By this temperature control, the adsorber is directly warmed and the temperature of the adsorber is maintained at a desired temperature, thereby promoting the separation of ammonia from the adsorbent. As a result, ammonia is smoothly supplied from the adsorber to the reactor, and ammonia reacts with the reactant in the reactor to generate heat. Thus, in this heat storage device, by using a reducing agent supply device that supplies a reducing agent to the selective reduction catalyst provided in the exhaust system, a part of the reducing agent supply device and the adsorber have a heat exchange structure. The adsorber can be temperature controlled without providing a separate temperature control device.

  In the heat storage device of the present invention, it is preferable that the connection line and a part of the reducing agent supply device have a heat exchange structure.

  By having such a heat exchange structure, the temperature of the connection line is adjusted by heat exchange with the reducing agent supply device. By this temperature control, when the ammonia having a high temperature in the reactor returns to the adsorber via the connection line, the high-temperature ammonia can be cooled and returned to the adsorber in the connection line. Thus, in this heat storage device, the reducing agent supply device provided in the exhaust system is used, and the reducing agent supply device and the connection line have a heat exchange structure, so that the reactor is not provided separately. It is possible to cool the high-temperature ammonia from the furnace and prevent the adsorber from becoming hot.

  In the above heat storage device of the present invention, the reducing agent is urea, and the heat exchange structure between the adsorber and a part of the reducing agent supply device is configured such that a part of the reducing agent supply line of the reducing agent supply device is connected to the outer periphery of the adsorber. A structure wound around a surface or a structure disposed in an adsorber may be used.

  The reducing agent supply device includes a reducing agent supply line for supplying urea as a reducing agent and moving and supplying the reducing agent (urea). In the heat storage device, a part of the reducing agent supply line is wound around the outer peripheral surface of the adsorber, whereby heat can be exchanged between the reducing agent supply line and the adsorber. Further, in the heat storage device, a part of the reducing agent supply line is arranged in the adsorber, so that heat can be exchanged between the part of the reducing agent supply line and the adsorber. Thus, this heat storage device can adjust the temperature of the adsorber by using a part of the reducing agent supply line so that heat can be exchanged with the adsorber, and the reducing agent supply line (in particular, the inside of the line). Flowing urea) can also be temperature controlled. When the temperature is adjusted to increase the temperature of urea, urea is easily hydrolyzed to become ammonia.

  In the heat storage device of the present invention, the reducing agent is urea, and the heat exchange structure between the adsorber and a part of the reducing agent supply device is a structure in which the adsorber is disposed in the reducing agent tank of the reducing agent supply device. Also good.

  The reducing agent supply device includes a reducing agent tank for supplying urea as a reducing agent and storing the reducing agent (urea). In this heat storage device, the adsorber is arranged in the reducing agent tank of the reducing agent supply device, so that heat can be exchanged between the reducing agent tank and the adsorber. In this way, this heat storage device can control the temperature of the adsorber by adopting a structure that can exchange heat with the adsorber using the reducing agent tank, and even if the adsorber is damaged during a vehicle collision, Ammonia is released into the atmosphere, and ammonia release into the atmosphere can be prevented.

  In the above heat storage device of the present invention, the reducing agent is urea, and the heat exchange structure between the connection line and a part of the reducing agent supply device is such that a part of the connection line is disposed in the reducing agent tank of the reducing agent supply device. It is good also as a structure to do. Thus, this heat storage device can effectively cool the high-temperature ammonia from the reactor in the reducing agent tank by arranging a part of the connection line in the reducing agent tank so that heat can be exchanged. .

  In the heat storage device of the present invention, it is preferable that a part of the connection line arranged in the reducing agent tank has a structure that is easily broken by an impact force generated when the vehicle collides. As described above, in this heat storage device, a part of the connection line arranged in the reducing agent tank is easily broken by the impact force of the vehicle collision, so that the part has priority over other parts at the time of the vehicle collision. As a result, the ammonia is released into the reducing agent tank from the destroyed part, and the release of ammonia into the atmosphere can be prevented.

  According to the present invention, by using a reducing agent supply device that supplies a reducing agent to a selective reduction catalyst provided in an exhaust system, a part of the reducing agent supply device and an adsorber or a connection line have a heat exchange structure. The adsorber and the connection line can be temperature-controlled without separately providing a temperature control device.

It is a schematic block diagram of the exhaust purification system provided with the heat storage apparatus which concerns on this Embodiment. It is an example of the pipe structure of the connection line arrange | positioned in the urea tank of FIG. 1, (a) is a structure which has a level | step difference, (b) is a structure which has a notch. It is a schematic block diagram of the exhaust gas purification system provided with the heat storage apparatus which concerns on other embodiment.

  Hereinafter, an embodiment of a heat storage device according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected about the element which is the same or it corresponds in each figure, and the overlapping description is abbreviate | omitted.

  In the present embodiment, the heat storage device according to the present invention is applied to a heat storage device provided in an exhaust purification system provided in an exhaust system of a vehicle engine. The exhaust purification system according to the present embodiment is a system that purifies harmful substances (environmental pollutants) contained in exhaust gas discharged from an engine (particularly a diesel engine). The exhaust purification system according to the present embodiment includes a catalyst DOC [Diesel Oxidation Catalyst] and an SCR [Selective Catalytic Reduction] and a filter DPF [Diesel Particulate Filter], and also includes a chemical heat storage device for warming up the catalyst. ing. The exhaust purification system according to the present embodiment also includes a urea spray system in which the SCR is a urea SCR system and sprays urea water as a reducing agent.

  With reference to FIG.1 and FIG.2, the exhaust gas purification system 1 which concerns on this Embodiment is demonstrated. FIG. 1 is a schematic configuration diagram of an exhaust purification system including a heat storage device according to the present embodiment. FIG. 2 is an example of a pipe structure of a connection line disposed in the urea tank of FIG. 1, (a) is a structure having a step, and (b) is a structure having a notch.

  The exhaust purification system 1 includes a diesel oxidation catalyst (DOC) 4, a diesel exhaust particulate removal filter (DPF) 5, and a selective reduction catalyst (from the upstream side to the downstream side of the exhaust passage 3 connected to the exhaust side of the engine 2. SCR) 6 and a urea spray system 7 for the SCR 6. In the present embodiment, the engine 2 corresponds to the internal combustion engine described in the claims, the DOC4 and SCR6 correspond to the catalyst described in the claims, and the SCR6 corresponds to the selective reduction catalyst described in the claims. The urea spray system 7 corresponds to the reducing agent supply device described in the claims.

DOC4 is a catalyst that oxidizes HC, CO, etc. contained in the exhaust gas. The DPF 5 is a filter that collects and removes PM contained in the exhaust gas. The SCR 6 is a catalyst that reduces and purifies NOx by chemically reacting ammonia (NH ₃ ) hydrolyzed from urea water as a reducing agent and NOx contained in the exhaust gas.

  The urea spray system 7 is a system for spraying urea water (reducing agent) upstream of the SCR 6 in the exhaust passage 3. Specifically, the urea spray system 7 includes a pump (not shown), a urea tank 7a, a urea spray line 7b, an injector 7c, and the like. The urea tank 7a is a tank that stores urea water. When the pump is operated, urea water is sent from the urea tank 7a to the urea spray line 7b. The urea spray line 7b is a pipe line that connects the urea tank 7a and the injector 7c and moves urea water from the urea tank 7a to the injector 7c. The injector 7 c is disposed between the DPF 5 and the SCR 6 in the exhaust passage 3 and sprays urea water into the exhaust passage 3. The sprayed urea water is hydrolyzed at a high temperature by being sprayed into the exhaust gas, and becomes ammonia. In the present embodiment, the urea tank 7a corresponds to the reducing agent tank described in the claims, and the urea spray line 7b corresponds to the reducing agent supply line described in the claims.

  In addition, the urea tank 7a is installed in the location which becomes normal temperature (for example, 25 degreeC) in a vehicle, for example, is installed in a trunk room. Therefore, the urea tank 7a (urea water in the tank) and the urea spray line 7b through which the urea water flows are usually at a temperature near normal temperature. The temperature of the heat storage device 8 (particularly the adsorber 8b) is controlled using the urea tank 7a and the urea spray line 7b near the normal temperature. The structure for adjusting the temperature of the heat storage device 8 will be described in detail later.

  The DOC 4 and the SCR 6 have a temperature range that can exhibit the ability to purify environmental pollutants, that is, an activation temperature. For example, the lower limit of the activation temperature of DOC4 is about 150 ° C, and the lower limit of the activation temperature of SCR6 is about 180 ° C. On the other hand, immediately after the engine 2 is started, the temperature of the exhaust gas immediately after being discharged from the engine 2 is a relatively low temperature of about 100 ° C. Thus, even immediately after the engine 2 is started, the temperature at the DOC 4 and the SCR 6 needs to be set to the activation temperature in order to exert the purification capability with the DOC 4 and the SCR 6. Therefore, the exhaust purification system 1 also includes a heat storage device 8 that warms up the catalyst. The exhaust purification system 1 is provided with a temperature sensor that detects the temperature of exhaust gas (or the temperature of the catalyst) discharged from the engine 2.

  The heat storage device 8 is a chemical heat storage device that warms up the catalyst without energy. That is, the heat storage device 8 normally stores the heat (exhaust heat) of the exhaust gas, and uses the heat to warm up the catalyst when necessary. The heat storage device 8 warms up the DOC 4 that is a catalyst located upstream on the exhaust passage 3. The heat storage device 8 includes a reactor 8a, an adsorber 8b, a connection line 8c, an on-off valve 8d, and the like.

The reactor 8a is provided along the outer peripheral surface of the DOC4. The reactor 8a has a molded body containing a solid or powdery reaction material that chemically reacts with ammonia. The reaction material, for _example, MgCl _2, CaCl _2, there is _{NiCl 2, ZnCl 2, SrCl 2} .

  The adsorber 8b is installed at a place where the urea spray line 7b can be installed. The adsorber 8b incorporates activated carbon as an adsorbent that physically adsorbs ammonia. Therefore, in the adsorber 8b, ammonia is stored in a state of being physically adsorbed with the activated carbon. In order for the adsorber 8b to physically adsorb ammonia with the activated carbon or to separate the ammonia from the activated carbon, it is necessary to maintain the temperature of the adsorber 8b at a desired temperature (for example, near normal temperature). In order to maintain this desired temperature, the adsorber 8b needs to be temperature-controlled.

  The adsorber 8b is provided with a temperature sensor (not shown) for detecting the internal temperature and a pressure sensor (not shown) for detecting the pressure. When the temperature and pressure detected by each sensor satisfy predetermined conditions, it can be determined that ammonia has returned from the reactor 8a to the adsorber 8b and that all the ammonia has been physically adsorbed with the activated carbon. As this predetermined condition, a conventionally known condition is applied.

  The connection line 8c is a pipe line that connects the reactor 8a and the adsorber 8b and moves ammonia between the reactor 8a and the adsorber 8b. The connection line 8c is arranged so that a part thereof passes through the urea tank 7a. The on-off valve 8d is disposed in the middle of the connection line 8c. When the on-off valve 8d is opened, ammonia can be transferred between the reactor 8a and the adsorber 8b via the connection line 8c. The opening / closing control of the opening / closing valve 8d is performed by an ECU [Electronic Control Unit] (not shown) that controls the engine 2.

  A structure for controlling the temperature of the heat storage device 8 (particularly the adsorber 8b) using the urea spraying system 7 (particularly the urea tank 7a and the urea spray line 7b) will be described. As a structure for adjusting the temperature, there are a structure in which a part of the urea spray line 7b and the adsorber 8b exchange heat, and a structure in which the urea tank 7a and a part of the connection line 8c exchange heat.

  A heat exchange structure between a part of the urea spray line 7b and the adsorber 8b will be described. As described above, the adsorber 8b is installed at a place where the urea spray line 7b is installed. Then, a part of the pipe 7d in the urea spray line 7b is wound along the outer peripheral surface of the adsorber 8b, whereby heat is exchanged between the wound pipe 7d and the adsorber 8b. With this structure, the adsorber 8b can be warmed by the pipe 7d through which urea water near normal temperature flows, and the temperature of the adsorber 8b is maintained at a desired temperature (for example, near normal temperature). Separation can be promoted. Also, with this structure, the pipe 7d can be warmed by the adsorber 8b, and the hydrolysis of urea water flowing in the pipe 7d can be promoted.

  Although FIG. 1 depicts a state in which the pipe 7d is wound around the adsorber 8b about 2 to 3 times, actually, the pipe 7d is wound as much as possible around the adsorber 8b. The pipe 7d is wound in close contact with the adsorber 8b. The longer the length of the pipe 7d wound around the adsorber 8b, the more heat exchange is performed between the pipe 7d and the adsorber 8b, and the temperature control effect becomes higher.

  A heat exchange structure between the urea tank 7a and a part of the connection line 8c will be described. As described above, the connection line 8c is arranged so that a part thereof passes through the urea tank 7a. A part of the pipe 8e in the connection line 8c is inserted into the urea tank 7a and arranged in a loop shape, so that the pipe 8e in the urea tank 7a and the urea tank 7a (particularly urea water in the tank) are arranged. ) To exchange heat with each other. With this structure, high-temperature ammonia (ammonia regenerated in the reactor 8a and returning to the adsorber 8b) flowing in the pipe 8e can be cooled, and the adsorber 8b can be prevented from reaching a high temperature.

  Although FIG. 1 depicts a state where the pipe 8e is looped about two to three times in the urea tank 7a, the pipe 8e is actually looped as many times as possible in the urea tank 7a. As the length of the pipe 8e in the urea tank 7a is longer, more heat exchange is performed between the pipe 8e and the urea tank 7a (urea water in the tank), and the temperature control effect is enhanced.

  Furthermore, it is preferable that a predetermined portion of the pipe 8e inserted into the urea tank 7a is easily broken. The structure that is easily destroyed is that when the vehicle collides, the impact force of the collision acts on the connection line 8c, and when the pipe 8e in the urea tank 7a is stressed accordingly, It is a structure that is easier to break than the place. Examples of the structure that is easily destroyed include a structure in which the portion is easily broken, a structure that is easily detached, and a structure that is easily perforated.

As the disrupted structure easy, for example, to increase the level difference of a predetermined portion of the pipe 8e ₁ as a pipe 8e ₁ shown in FIG. 2 (a), as the pipe 8e ₂ shown in FIG. 2 (b) The pipe 8e ₂ has a structure in which a notch is provided at a predetermined location. Such a step or notch may be formed in the middle of one pipe, or two pipes having different diameters may be joined or two pipes having notched ends may be joined. Good.

  The operation of the heat storage device 8 and its temperature control function in the exhaust purification system 1 configured as described above will be described. While the vehicle is stopped (the engine 2 is stopped), the on-off valve 8d is closed. Therefore, even if ammonia is separated from the activated carbon in the adsorber 8b, ammonia is not supplied to the reactor 8a via the connection line 8c.

When the temperature of the exhaust gas discharged from the engine 2 is lower than a predetermined temperature (a temperature lower than the activation temperature of the DOC 4 or SCR 6) after the engine 2 is started (such as immediately after the engine 2 is started), the on-off valve 8d is controlled by the ECU. It is opened and ammonia is supplied to the reactor 8a via the connection line 8c. At this time, the pressure of the adsorber 8b is higher than the pressure of the reactor 8a, and ammonia moves to the reactor 8a side. In the reactor 8a, the supplied ammonia and a reaction material (for example, MgCl ₂ ) contained in the molded body chemically react and chemisorb (coordinate bond), and generate heat from the molded body. That is, the reaction from the left side to the right side in the following reaction formula occurs. And each temperature of DOC4 and SOC6 rises with the heat | fever generate | occur | produced from the molded object of the reactor 8a, and rises to the activation temperature suitable for purification | cleaning of the environmental pollutant in exhaust gas.
MgCl ₂ + 6NH ₃ ⇔MgCl ₂ · 6 (NH ₃ ) + heat

  At this time, if the urea water in the urea tank 7a is injected from the injector 7c through the urea spray line 7b, between the pipe 7d of the urea spray line 7b wound around the adsorber 8b and the adsorber 8b. Heat exchange takes place. As a result, the temperature of the adsorber 8b tends to decrease as ammonia is separated from the activated carbon in the adsorber 8b, but the adsorber 8b is warmed by heat exchange between the pipe 7d and the adsorber 8b, and the adsorber 8b The temperature drop is suppressed, and the temperature of the adsorber 8b is maintained at a desired temperature. Therefore, separation of ammonia from the activated carbon in the adsorber 8b is promoted, and ammonia is smoothly supplied from the adsorber 8b to the reactor 8a through the connection line 8c. As a result, the chemical reaction between ammonia and the reactant contained in the molded body is smoothly performed in the reactor 8a, and it is possible to prevent the generation of heat from taking time. As a result, the temperatures of DOC4 and SOC6 rise to the activation temperature in a short time.

When the temperature of the exhaust gas discharged from the engine 2 becomes higher than a predetermined temperature (a temperature higher than the activation temperature of the DOC 4 or SCR 6), exhaust heat of the exhaust gas is given to the molded body of the reactor 8a, whereby ammonia and a reaction material (MgCl ₂ ) separates and high temperature ammonia is generated. That is, the reaction from the right side to the left side in the above reaction formula occurs. Then, the separated ammonia returns from the reactor 8a to the adsorber 8b through the connection line 8c. At this time, the pressure of the reactor 8a is higher than the pressure of the adsorber 8b, and ammonia moves to the adsorber 8b side. In the adsorber 8b, activated carbon physically adsorbs and stores ammonia.

  At this time, heat exchange is performed between the urea tank 7a (particularly urea water in the tank) and the pipe 8e of the connection line 8c inserted in the urea tank 7a. As a result, the ammonia coming out of the reactor 8a is hot, but the hot ammonia is cooled by heat exchange with the pipe 8e in the urea tank 7a, and the adsorber 8b is heated to high temperature by the ammonia returned to the adsorber 8b. It is suppressed. Along with this, the pipe 7d of the urea spray line 7b wound around the adsorber 8b is also suppressed from becoming high temperature.

  As described above, the temperature and pressure of the adsorber 8b are detected by each sensor, and when the detected temperature and pressure satisfy predetermined conditions, all the ammonia is physically adsorbed with the activated carbon in the adsorber 8b. It is judged as a state. When it is determined in this way, the on-off valve 8d is closed under the control of the ECU.

  Further, when the impact force of the collision acts on the connection line 8c when the vehicle collides, the easily damaged portion of the pipe 8e in the urea tank 7a is destroyed. Ammonia leaks into the urea tank 7a from this destruction location, but ammonia dissolves in the urea water in the urea tank 7a. As a result, ammonia is not released into the atmosphere.

  According to this exhaust purification system 1 (particularly, the temperature control structure of the heat storage device 8), the urea spray system 7 provided in the exhaust purification system 1 is used, and the pipe 7d of the urea spray line 7b and the adsorber 8b exchange heat. By adopting such a structure, the temperature of the adsorber 8b can be adjusted without separately providing a temperature control device, and the separation of ammonia from the activated carbon in the adsorber 8b can be promoted. Since a separate temperature control device is not provided, power for operating the temperature control device is not required, energy loss can be reduced, and the cost of providing a separate temperature control device is not required. Moreover, warming up with respect to DOC4 and SCR6 can be performed in a short time. Furthermore, the temperature of the urea water supplied through the urea spray line 7b can be controlled by employing a structure in which the pipe 7d of the urea spray line 7b is wound around the outer peripheral surface of the adsorber 8b. When the temperature is adjusted and the temperature of the urea water rises, the hydrolysis of the urea water can also be promoted.

  Moreover, according to the exhaust gas purification system 1, the temperature control apparatus is configured by using the urea spray system 7 provided in the exhaust gas purification system 1 so as to exchange heat between the urea tank 7a and the pipe 8e of the connection line 8c. Without providing it separately, it is possible to cool the high-temperature ammonia from the reactor 8a and prevent the adsorber 8b from reaching a high temperature. In particular, by arranging the pipe 8e in a loop shape in the urea tank 7a to exchange heat, the high-temperature ammonia in the pipe 8e can be effectively cooled in the urea tank 7a.

  Further, according to the exhaust gas purification system 1, the pipe 8e of the connection line 8c disposed in the urea tank 7a has a structure that is easily broken by the impact force of the vehicle collision. Therefore, ammonia leaks into the urea tank 7a from the destroyed portion, and the release of ammonia into the atmosphere can be prevented.

  As mentioned above, although embodiment which concerns on this invention was described, this invention is implemented in various forms, without being limited to the said embodiment.

  For example, in the present embodiment, the present invention is applied to an exhaust purification system including DOC and SCR as catalysts and DPF as a filter. However, various other configurations are possible as long as the system purifies exhaust gas by supplying a reducing agent to the catalyst. Applicable to exhaust gas purification systems. For example, the present invention can be applied to a system that reduces NOx by supplying light oil as a reducing agent to the SCR.

  Further, in this embodiment, the reactor of the heat storage device is arranged on the outer peripheral surface of the DOC in order to warm up the catalyst. However, it may be arranged in other places depending on the catalyst to be warmed up. For example, if the catalyst to be warmed up is an SCR, it may be disposed at a predetermined location in the exhaust passage upstream of the SCR or the outer peripheral surface of the SCR, or even in the case of a DOC, the exhaust upstream of the DOC. You may arrange | position in the predetermined location of a channel | path. Further, in this embodiment, the catalyst (DOC) is warmed up by the heat storage device, but the target to be directly warmed up by the heat storage device is not limited to the catalyst, and the dispersion plate and the exhaust pipe itself arranged upstream of the catalyst are used. You may make it raise the temperature of exhaust gas by warming.

  Further, in this embodiment, as a heat exchange structure between the adsorber and a part of the urea spray system, the urea spray line pipe is wound around the outer peripheral surface of the adsorber, but the urea spray line pipe is placed in the adsorber. Other arrangements may be employed, such as insertion and arrangement such that the urea tank and the adsorber are brought into contact with each other, or an adsorber 8b built in the urea tank 7a as shown in FIG. When the adsorber is built in the urea tank, when the vehicle collides, the adsorber is destroyed and ammonia leaks out, the ammonia is dissolved in the urea water of the urea tank, and the ammonia is not released into the atmosphere.

  In the present embodiment, the pipe of the connection line is arranged in a loop shape in the urea tank as a heat exchange structure between a part of the connection line and the urea tank. Other configurations such as winding around the surface or arranging the pipe in the urea tank in a state other than the loop may be adopted.

DESCRIPTION OF SYMBOLS 1 ... Exhaust purification system, 2 ... Engine, 3 ... Exhaust passage, 4 ... Diesel oxidation catalyst (DOC), 5 ... Diesel exhaust particulate removal filter (DPF), 6 ... Selective reduction catalyst (SCR), 7 ... Urea spray system, 7a ... urea tank, 7b ... urea spray line, 7c ... injector, 7d ... pipe, 8 ... heat storage device, 8a ... reactor, 8b ... adsorber, 8c ... connection line, 8d ... off valve, _8e, 8e 1, 8e ₂ ... pipe.

Claims (7)

A heat storage device for warming up at least a part of an exhaust system of an internal combustion engine of a vehicle,
A reactor disposed in the exhaust system and having a reactant that chemically reacts with ammonia to generate heat;
An adsorber for adsorbing and storing ammonia with an adsorbent;
A connection line connecting the reactor and the adsorber;
With
The exhaust system is provided with at least a selective reduction catalyst and a reducing agent supply device for supplying a reducing agent to the selective reduction catalyst,
The heat storage device, wherein the adsorber or the connection line and a part of the reducing agent supply device have a heat exchange structure.   The heat storage device according to claim 1, wherein the adsorber and a part of the reducing agent supply device have a heat exchange structure.   The heat storage device according to claim 1, wherein the connection line and a part of the reducing agent supply device have a heat exchange structure. The reducing agent is urea;
The heat exchange structure between the adsorber and a part of the reducing agent supply device is a structure in which a part of the reducing agent supply line of the reducing agent supply device is wound around the outer peripheral surface of the adsorber or disposed in the adsorber. The heat storage device according to claim 2, wherein the heat storage device has a structure. The reducing agent is urea;
The heat exchange structure between the adsorber and a part of the reducing agent supply device is a structure in which the adsorber is arranged in a reducing agent tank of the reducing agent supply device. Thermal storage device. The reducing agent is urea;
The heat exchange structure between the connection line and a part of the reducing agent supply device is a structure in which a part of the connection line is arranged in a reducing agent tank of the reducing agent supply device. The heat storage device described in 1.   7. The heat storage device according to claim 6, wherein a part of the connection line disposed in the reducing agent tank has a structure that is easily broken by an impact force generated when a vehicle collides.

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