JP2008031931A - Exhaust gas reforming device and exhaust gas reforming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inhibit temperature drop of exhaust gas to be reformed. <P>SOLUTION: The exhaust gas reforming device 20 forms reformed gas containing hydrogen by reforming mixture of fuel Fr for reforming and exhaust gas Ex exhausted from an internal combustion engine by a reforming catalyst. The exhaust gas reforming device 20 is provided with: a main exhaust gas passage 25C of which inside exhaust gas Ex passes through and of which inner surface conversion catalyst is carried on; and a reforming passage 25R inside of which the reforming catalyst is carried, which is arranged with crossing the main exhaust gas passage 25C, and which a part of exhaust gas Ex passes through. The main exhaust gas passage 25C and the reforming passage 25R are stored in a casing 21. Exhaust gas Ex introduced in the exhaust gas reforming device 20 is branched in an exhaust gas introduction casing H and is divided to the main exhaust gas passage 25C and the reforming passage 25R. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exhaust gas reforming apparatus and an exhaust gas reforming system for recirculating a reformed gas containing hydrogen obtained by reforming a mixture of fuel and exhaust gas discharged from an internal combustion engine to an intake passage of the internal combustion engine. About.

  A modification of the exhaust gas is made so that a reformed gas obtained by adding a hydrocarbon-based fuel to the exhaust gas discharged from the internal combustion engine and reforming the mixture of the two with a reforming catalyst can be supplied to the intake pipe of the internal combustion engine. A quality device is known (for example, Patent Document 1).

JP-A-6-264732

  However, the technique disclosed in Patent Document 1 requires a pipe for supplying exhaust gas discharged from the internal combustion engine to the reformer. As a result of the heat energy of the exhaust gas escaping from the pipe, the exhaust gas used for reforming. As a result, there is a problem that the reforming efficiency is lowered and the amount of generated hydrogen is lowered. Therefore, the present invention has been made in view of the above, and an object thereof is to provide an exhaust gas reforming apparatus and an exhaust gas reforming system that can suppress a temperature drop of exhaust gas to be reformed.

  In order to solve the above-described problems and achieve the object, an exhaust gas reforming apparatus according to the present invention is produced by reforming a mixture of fuel and exhaust gas discharged from an internal combustion engine with a reforming catalyst. The reformed gas containing hydrogen is recirculated to the intake passage of the internal combustion engine, and the main exhaust gas passage through which the exhaust gas passes, and the reforming catalyst is provided therein, and the main exhaust gas passage And a reforming passage through which a part of the exhaust gas discharged from the internal combustion engine passes, a housing for storing the main exhaust gas passage and the reforming passage therein, and an inlet side of the exhaust gas And an exhaust gas distribution unit that distributes the exhaust gas discharged from the internal combustion engine inside the casing and distributes the exhaust gas to the main exhaust gas passage and the reforming passage.

  The exhaust gas reforming apparatus according to the present invention splits the reforming exhaust gas inside the reforming apparatus, and flows the split exhaust gas through the reforming passage and the main exhaust passage. As a result, the path through which the exhaust gas for reforming passes can be shortened. As a result, since the amount of heat released from the exhaust gas used for reforming can be suppressed before being introduced into the reforming passage, the temperature reduction of the exhaust gas used for reforming can be suppressed.

  The exhaust gas reforming apparatus according to the present invention is characterized in that, in the exhaust gas reforming apparatus, a purification catalyst for purifying the exhaust gas is provided inside the main exhaust gas passage.

  The exhaust gas reforming apparatus according to the present invention is characterized in that, in the exhaust gas reforming apparatus, the casing is cylindrical.

  In the exhaust gas reforming apparatus according to the present invention, the exhaust gas reforming apparatus is configured to introduce the exhaust gas into the reforming passage in the exhaust gas distribution section on the exhaust gas inlet side of the reforming passage. An exhaust gas guide is provided, and a passage for guiding the exhaust gas to the reforming passage is formed between the exhaust gas guide and the housing.

  The exhaust gas reforming apparatus according to the present invention is characterized in that, in the exhaust gas reforming apparatus, the exhaust gas guide is provided with a protrusion protruding toward the housing.

  In the exhaust gas reforming apparatus according to the next aspect of the present invention, in the exhaust gas reforming apparatus, moisture supply means for supplying moisture to the exhaust gas flowing into the reforming passage, and cooling the reformed gas to the intake passage A boiling cooling device that generates steam using heat of the gas cooling means to be refluxed and supplies the steam to the moisture supply means.

  An exhaust gas reforming apparatus according to the present invention includes, in the exhaust gas reforming apparatus, a stirring container into which the fuel is injected, and the fuel is injected into the stirring container and then flows into the reforming passage. The exhaust gas is supplied to the exhaust gas.

  The exhaust gas reforming apparatus according to the present invention is characterized in that, in the exhaust gas reforming apparatus, the boiling cooling device generates steam by using heat of at least one of the gas cooling means or the stirring vessel. And

  An exhaust gas reforming system according to the present invention includes an internal combustion engine, the exhaust gas reformer provided in the middle of an exhaust gas passage through which exhaust gas discharged from the internal combustion engine flows, and the reformer generated by the exhaust gas reformer. A gas recirculation passage for recirculating gas to the intake passage of the internal combustion engine; and a recirculation flow rate adjusting means provided between the exhaust gas reforming device and the intake passage.

  This exhaust gas reforming system includes the reforming device, splits the reforming exhaust gas inside the reforming device, and flows the split exhaust gas through the reforming passage and the main exhaust passage. As a result, the path through which the exhaust gas for reforming passes can be shortened. As a result, since the amount of heat released from the exhaust gas used for reforming can be suppressed before being introduced into the reforming passage, the temperature reduction of the exhaust gas used for reforming can be suppressed.

  In the exhaust gas reforming system according to the next aspect of the present invention, in the exhaust gas reforming system, the pulsation of the reformed gas is provided in the middle of the gas recirculation passage and between the exhaust gas reforming device and the recirculation flow rate adjusting means. A pulsation reducing container for reducing the above is provided.

  The exhaust gas reforming system according to the present invention is directed to the exhaust gas reforming apparatus in the exhaust gas reforming system and in the middle of the gas recirculation passage and between the exhaust gas reforming apparatus and the pulsation reducing container. A check valve for suppressing the flow of the reformed gas is provided.

  The exhaust gas reforming apparatus and the exhaust gas reforming system according to the present invention can suppress a decrease in the temperature of exhaust gas used for reforming.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited by the best mode for carrying out the invention (hereinafter referred to as an embodiment). In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, or substantially the same, so-called equivalent ranges. The present invention can be preferably applied particularly to an internal combustion engine mounted on a vehicle such as a passenger car, a bus, or a truck.

(Embodiment 1)
The first embodiment is characterized in that the amount of heat released from the reforming exhaust gas is suppressed by diverting the exhaust gas to be reformed inside the exhaust gas reforming apparatus, thereby suppressing the temperature drop of the reforming exhaust gas.

FIG. 1 is an overall configuration diagram of an exhaust gas reforming system according to a first embodiment. The overall configuration of the exhaust gas reforming system according to this embodiment will be described with reference to FIG. An exhaust gas reforming system 100 according to this embodiment includes an internal combustion engine 1 and an exhaust gas reforming device 20. Part of the exhaust gas Ex discharged from the internal combustion engine 1 is led to an exhaust gas reforming device 20 (hereinafter referred to as a reforming device) which is an exhaust gas reforming means. Then, hydrogen (H ₂ ) is generated by supplying fuel (reforming fuel) Fr for reforming, including hydrocarbon (HC), to the exhaust gas Ex led to the reformer 20. Then, a gas containing hydrogen (hereinafter referred to as reformed gas) Exr obtained by the reforming reaction is recirculated to the internal combustion engine 1.

Although the internal combustion engine 1 has four cylinders arranged in series, the number of cylinders and the cylinder arrangement are not limited to this. The internal combustion engine 1 may be a so-called rotary internal combustion engine. The fuel (fuel for the internal combustion engine) Fe supplied to the internal combustion engine 1 is supplied to the port injection valve 6 through the fuel passage 73 for the internal combustion engine by the feed pump 71 in the fuel tank 70. The internal combustion engine fuel Fe is injected into the intake passage 3 from the port injection valve 6 and forms an air-fuel mixture with the air A passing through the intake passage 3. The mixture is introduced through the intake manifold 7 _{1-7 4} constituting the intake passage to each cylinder 1s ₁ ~1s _4.

In this embodiment, the fuel Fe for the internal combustion engine is supplied to each cylinder of the internal combustion engine 1 by the single port injection valve 6, but the port injection valves are prepared for the number of cylinders, and the intakes of the cylinders 1s _{1 to} 1s ₄ The internal combustion engine fuel Fe may be supplied to the manifolds 7 _{1 to} 7 ₄ . Further, the internal combustion engine fuel Fe may be supplied to the internal combustion engine 1 by using a so-called direct injection valve that directly injects fuel into the cylinder instead of the port injection valve. Further, a port injection valve and a direct injection valve may be provided, and the fuel injection ratio of both may be changed according to the operating conditions of the internal combustion engine 1 to supply the internal combustion engine fuel Fe to the internal combustion engine 1.

  The air A supplied to the internal combustion engine 1 is sent to the internal combustion engine 1 after dust and the like are removed by an air cleaner 13 attached to the inlet of the intake passage 3. The flow rate of the air A supplied to the internal combustion engine 1 is adjusted by a throttle valve 4 provided in the intake passage 3. The opening degree of the throttle valve 4 is interlocked with the accelerator 47P. In this embodiment, the opening degree of the accelerator 47P is detected by the accelerator opening degree sensor 47 and is taken into the engine ECU 50. The engine ECU 50 adjusts the opening of the throttle valve 4 based on the accelerator opening information from the accelerator opening sensor 47.

  When the accelerator opening increases, the opening of the throttle valve 4 increases, and when the accelerator opening decreases, the opening of the throttle valve 4 decreases. The flow of air supplied to the internal combustion engine 1 is measured by an air flow sensor 42 provided in the intake passage 3 and upstream of the throttle valve 4, and the measured value is taken into an engine ECU (Electronic Control Unit) 50. The engine ECU 50 determines the fuel injection amount Qf for the internal combustion engine 1 from the intake air amount Ga measured by the air flow sensor 42 and the engine rotational speed NE of the internal combustion engine 1 measured by the rotational speed sensor 43.

The air-fuel mixture burned in each cylinder 1 s _{1 to 1} s ₄ of the internal combustion engine 1 becomes exhaust gas Ex and is discharged to the exhaust manifold 8. The exhaust gas Ex is introduced into the reformer 20 through the exhaust passage 9 and gives heat for reforming the exhaust gas Ex. The exhaust gas Ex discharged from the reformer 20 is released into the atmosphere. An A / F (Air / Fuel) sensor 45 is attached to the exhaust passage 9 and measures the air-fuel ratio of the exhaust gas Ex. Then, the combustion state of the internal combustion engine 1 is determined from the air-fuel ratio of the exhaust gas Ex, and when it deviates from the predetermined air-fuel ratio, the fuel injection amount determined by the engine ECU 50 is corrected.

  A reformer 20 is connected to the exhaust passage 9, and exhaust gas Ex discharged from the internal combustion engine 1 is supplied to the reformer 20. The reformer 20 according to this embodiment has a configuration in which a part of the exhaust gas Ex discharged from the internal combustion engine 1 is reformed and the remaining exhaust gas is purified by a purification catalyst. A part of the exhaust gas Ex supplied to the exhaust gas reforming device 20 is divided as reforming exhaust gas inside the reforming device 20. The exhaust gas Ex that is not subjected to reforming is purified by a purification catalyst included in the reforming device 20 in the process of passing through the reforming device 20.

  In this embodiment, when the reforming fuel Fr is supplied to the exhaust gas Ex to be reformed, the reforming fuel Fr is injected into the stirring vessel 16 connected to the reformer 20, and the After the reforming fuel Fr is stirred, the reforming fuel Fr is supplied to the exhaust gas Ex. A reforming fuel injection valve 2 is attached to the stirring vessel 16. The reforming fuel Fr is supplied to the reforming fuel injection valve 2 from the feed pump 71 in the fuel tank 70 through the reforming fuel passage 72. The reforming fuel injection valve 2 supplies the reforming fuel Fr into the stirring container 16, and the reforming fuel Fr is sufficiently stirred in the stirring container 16. This facilitates mixing of the reforming fuel Fr and the exhaust gas Ex used for reforming.

The stirring vessel 16 is connected to a path through which the reforming exhaust gas Ex is supplied to the reformer 20, and the stirred reforming fuel Fr is exhaust gas that is used for reforming in the reformer 20. Supplied to Ex. In the reformer 20, the reforming fuel Fr and the exhaust gas Ex are mixed to form the reforming mixture Gmr. In this embodiment, the reforming fuel Fr is a part of the internal combustion engine fuel Fe supplied to the cylinders 1s ₁ to 1s _{4 of} the internal combustion engine 1, and the operating conditions of the internal combustion engine 1 and the reforming catalyst. The injection amount Qfr of the reforming fuel Fr is determined according to the temperature and the like.

  Here, since the stirring vessel 16 is disposed in the vicinity of the reformer 20 that is exposed to a high temperature, the reforming fuel injection valve 2 is exposed to a high temperature, which may reduce durability. For this reason, the stirring vessel 16 includes exhaust gas cooling means for cooling the temperature of the exhaust gas Ex. As the exhaust gas cooling means, for example, a water jacket is used and attached to the stirring vessel 16. As a result, the stirring vessel 16 is cooled, the temperature rise of the reforming fuel injection valve 2 is suppressed, and a decrease in the durability of the reforming fuel injection valve 2 is suppressed.

  The reforming gas mixture Gmr generated in the reformer 20 is reformed by the reforming catalyst provided in the reformer 20. Although the detailed configuration of the reforming device 20 will be described later, a schematic configuration of the reforming device 20 will be described here. The reformer 20 includes a reforming passage through which the reforming gas mixture Gmr passes. A reforming catalyst is provided in the reforming passage (for example, a reforming catalyst is provided on the inner surface of the reforming passage). Carry). Further, the reformer 20 is provided with a main exhaust gas passage through which the exhaust gas Ex passes separately from the reforming passage, and the exhaust gas Ex that is not guided to the reforming passage passes through the main exhaust gas passage. In this embodiment, a purification catalyst is provided inside the main exhaust gas passage (for example, a purification catalyst is carried on the inner surface of the main exhaust gas passage), and the exhaust gas passing through the main exhaust gas passage is purified.

With such a configuration, the reformer 20 constitutes a heat exchanger, gives heat of the exhaust gas Ex not guided to the reforming passage to the reforming catalyst, and the temperature of the reforming catalyst (hereinafter referred to as reforming catalyst temperature). Is maintained at the activation temperature Ta or higher, the reforming gas mixture Gmr flowing in the reforming passage is reformed, and the reformed gas Exr containing hydrogen is generated. Here, as the reforming catalyst, for example, a rhodium (Rh) -based catalyst, a catalyst in which rhodium (Rh) and alumina (Al ₂ O ₃ ) are combined, or the like is used.

  A reforming catalyst bed temperature sensor 44 is attached to the reformer 20 in order to measure the temperature of the reforming catalyst. Since it is difficult to measure the temperature of the reforming catalyst itself, the temperature of the catalyst bed carrying the reforming catalyst is measured to obtain the reforming catalyst temperature. When the reforming catalyst temperature is low, the hydrogen concentration in the reformed gas Exr is low, and the hydrogen concentration in the reformed gas Exr increases as the reforming catalyst temperature increases. For this reason, the reforming catalyst temperature is monitored by the reforming catalyst bed temperature sensor 44 so that the reforming of the exhaust gas Ex is started after the reforming catalyst temperature becomes equal to or higher than the activation temperature Ta. When a rhodium-based reforming catalyst is used, the activation temperature Ta is about 600 ° C.

A gas recirculation passage 10 that connects the reforming passage of the reforming device 20 and the intake passage 3 is attached to the reforming device 20. The gas recirculation passage 10 recirculates the exhaust gas Ex or the reformed gas Exr to the intake side of the internal combustion engine 1, that is, the intake passage 3. As a result, the reformed gas Exr is recirculated to the combustion chambers of the cylinders 1 s _{1 to 1} s ₄ of the internal combustion engine 1. A gas cooler 12 is provided in the gas recirculation passage 10 to cool the reformed gas Exr. Further, a reflux flow rate adjusting valve 5 as a reflux flow rate adjusting means is provided between the gas cooler 12 and the outlet 10o of the gas reflux passage 10 and is caused to return to the intake passage 3 in response to a command from the engine ECU 50. The flow rate of the reformed gas Exr is adjusted.

In this embodiment, although the reformed gas Exr is refluxed at once to the intake passage 3 of the internal combustion engine 1, provided with a reflux flow control valve 5 for each cylinder 1s ₁ ～1S ₄ of the internal combustion engine 1, each cylinder 1s _The reformed gas Exr may be refluxed individually for each of _{1 to} 1s ₄ . The flow rate of the reformed gas Exr to be recirculated to the intake passage 3 is adjusted by the opening degree of the recirculation flow rate adjusting valve 5 and the valve opening time.

  In this embodiment, a check valve 15 that suppresses the flow of the reformed gas Exr toward the exhaust gas reformer 20 is provided at the outlet of the gas cooler 12 to suppress the backflow of the reformed gas Exr. Further, a pulsation reducing container 14 is provided between the check valve 15 and the reflux flow rate adjustment valve 5. Since the gas recirculation passage 10 is connected to the exhaust passage 9 via the reforming passage of the reformer 20, there is a risk that the reformed gas Exr may also pulsate due to the pulsation of the exhaust gas Ex discharged from the internal combustion engine 1. There is. As a result, the flow rate of the reformed gas Exr to be recirculated to the intake passage 3 may be inaccurate. For this reason, the pulsation of the reformed gas Exr is reduced by the pulsation reducing container 14 and the check valve 15. Thus, the reformed gas Exr is recirculated to the intake passage 3 at the determined flow rate, and the internal combustion engine 1 can be operated stably. Further, the moisture contained in the reformed gas Exr can be removed by the pulsation reducing container 14, and protection of the gas cooler 12 can be expected by reducing the pulsation of the reformed gas Exr. Next, the reforming reaction in the reformer 20 will be described.

The reforming gas mixture Gmr of the reforming fuel Fr and the exhaust gas Ex is reformed by the reforming reaction shown in the equation (1) by the reforming catalyst provided on the inner surface of the reforming passage of the reformer 20. Reformed gas Exr.
_{1.56 (7.6CO 2 + 6.8H 2 O} + 40.8N 2) + 3C 7.6 H 13.6 + 4122kJ → 31H 2 + 34.7CO + 63.6N 2 ··· (1)

  Here, the first term on the left side represents the exhaust gas Ex, the second term on the left side represents fuel (hydrocarbon CH, gasoline in this embodiment), and the right side represents the reformed gas Exr. Hydrogen contained in the reformed gas Exr on the right side is 24 vol% with respect to the total reformed gas volume. Further, this reforming reaction is an endothermic reaction, whereby the thermal energy of the exhaust gas Ex is recovered. In this way, since the exhaust gas Ex is reformed by the endothermic reaction, even if the amount of fuel supplied to the internal combustion engine 1 is the same, the amount of heat generated in the combustion in the internal combustion engine 1 by the amount absorbed by the heat of the exhaust gas Ex. Will increase.

The calorific value of hydrogen (H ₂ ) is 241.7 kJ / mol, and the calorific value of gasoline (CH _1.869 ) is 596.5 kJ / mol. However, the reforming reaction of the formula (1) generates 31 moles of hydrogen from 3 moles of gasoline (fuel). Therefore, when the calorific value is multiplied by the change in the number of moles due to the reforming of the formula (1), the calorific value of the reformed gas Exr is greatly increased as compared with the case where gasoline alone is combusted. As a result, the output torque of the internal combustion engine 1 is increased and the fuel consumption is reduced.

  The reformed gas Exr generated by the reformer 20 is introduced into the intake passage 3 through the gas recirculation passage 10. Since the reformed gas Exr becomes a high temperature around 700 ° C., it is cooled by the gas cooler 12 provided in the middle of the gas recirculation passage 10 and then introduced into the intake passage 3. The flow rate (recirculation flow rate) of the reformed gas Exr introduced into the intake passage 3 is controlled by the recirculation flow rate adjustment valve 5. The flow rate of the reformed gas Exr introduced into the intake passage 3 is determined based on the operating conditions of the internal combustion engine 1 so that the maximum reformed gas under the operating conditions can be introduced into the internal combustion engine 1. Will be described later. In this case, in consideration of the amounts of hydrogen and carbon monoxide (CO) contained in the reformed gas Exr, the fuel injection amount of the port injection valve 6 is reduced to optimize the air-fuel ratio A / F.

Hydrogen (H ₂ ) contained in the reformed gas Exr has a maximum ignition energy of about 1/10 as compared with gasoline, and a maximum combustion rate of slightly less than 10 times. For this reason, hydrogen burns faster than gasoline. When the reformed gas Exr containing hydrogen obtained by the reforming reaction is supplied to the internal combustion engine 1, the combustion improvement effect is obtained by the hydrogen in the reformed gas Exr. In the operation of the internal combustion engine 1, so-called EGR (Exhaust Gas Recirculation) in which the exhaust gas Ex is recirculated to the intake side may be executed.

  If EGR is executed when the internal combustion engine 1 is operated at a light load, the pump loss is reduced and fuel consumption can be reduced. However, if the exhaust gas Ex has an excessive flow rate (EGR amount), the combustion speed becomes slow and combustion occurs. Gets worse. As a result, the output torque of the internal combustion engine 1 is lowered and drivability is deteriorated. In the internal combustion engine 1 according to this embodiment, since the reformed gas Exr containing hydrogen is recirculated to the internal combustion engine 1, even when the recirculation amount of the reformed gas Exr is increased, rapid combustion of hydrogen causes deterioration of combustion. Is suppressed. As a result, it is possible to suppress a decrease in output torque due to deterioration in combustion and suppress deterioration in drivability.

  Further, if the EGR is performed when the internal combustion engine 1 is in a high load (for example, operation in the WOT region or operation in a region where the load factor exceeds about 80%), the temperature of the combustion chamber can be lowered. = 1) The range that can be operated is expanded. However, combustion may deteriorate due to EGR, output torque may decrease, and drivability may deteriorate. Since the internal combustion engine 1 according to this embodiment recirculates not only the exhaust gas Ex but also the reformed gas Exr containing hydrogen to the internal combustion engine 1, the deterioration of combustion is suppressed by rapid combustion of hydrogen in the reformed gas Exr. The Further, since knocking can be improved by rapid combustion of hydrogen, the ignition timing can be advanced and the output torque of the internal combustion engine 1 can be improved. As a result, it is possible to suppress a decrease in output torque due to deterioration in combustion and suppress deterioration in drivability. Next, the structure of the reformer 20 will be described.

  FIG. 2-1 is a perspective view illustrating the exhaust gas reforming apparatus according to the first embodiment. FIG. 2-2 is a cross-sectional view illustrating the exhaust gas reforming apparatus according to the first embodiment. FIG. 2-3 is an AA arrow view of FIG. 2-2. FIG. 2-4 is a BB view of FIG. 2-2. FIG. 3-1 is a perspective view illustrating a heat exchange structure provided in the exhaust gas reforming apparatus according to the first embodiment. FIG. 3-2 is a front view illustrating the heat exchange structure included in the exhaust gas reforming apparatus according to the first embodiment. FIG. 3C is a plan view of the heat exchange structure included in the exhaust gas reforming apparatus according to the first embodiment. 3-4 is a side view showing the heat exchange structure included in the exhaust gas reforming apparatus according to Embodiment 1. FIG. 3-5 is a partial perspective view illustrating another example of the heat exchange structure provided in the exhaust gas reforming apparatus according to Embodiment 1. FIG.

  As illustrated in FIGS. 2A and 2B, the reformer 20 according to this embodiment is configured by disposing a heat exchange structure 24 in a housing 21. The casing 21 includes an exhaust gas introduction section casing 21H, a trunk section 21B, and an exhaust gas discharge section casing 21F. As shown in FIGS. 2-1, 2-3, and 2-4, the body 21B of the casing 21 has a cylindrical shape, and is in the axial direction of the casing 21 (parallel to the direction in which the exhaust gas Ex flows through the main exhaust gas passage). The cross-sectional shape perpendicular to) is a circle. Further, the exhaust gas introduction unit housing 21H and the exhaust gas discharge unit housing 21F have a truncated cone shape, and the cross-sectional shape perpendicular to the axial direction of the housing 21 is a circle. Thus, the housing | casing 21 is comprised by the cylindrical shape as a whole. Thereby, the rigidity of the housing 21 can be improved. As a result, the vibration of the casing 21 due to pulsation in the exhaust passage can be suppressed, and the radiated sound from the casing 21 can be reduced.

  The shape of the heat exchange structure 24 is a rectangular parallelepiped (quadrangular prism shape), and is stored inside the trunk portion 21 </ b> B constituting the housing 21. A space (outer main exhaust gas passage) 25CS formed between the side portion 24S1 of the heat exchanging structure 24 where the reforming passage 25R is not open and the inner surface 21I of the casing 21 facing the side portion 24S1 is formed. The exhaust gas Ex discharged from the internal combustion engine 1 and not subjected to reforming flows.

  As shown in FIGS. 2-2 and 2-4, the side 24S2 of the heat exchanging structure 24 where the inlet 25RI of the reforming passage 25R opens, and the inner surface 21I of the casing 21 facing the side 24S2 In the space formed between the two, an exhaust gas outlet side sealing means 27E is provided on the exhaust gas discharge unit casing 21F side. As a result, an opening O is formed on the exhaust gas introduction part casing 21H side of the space, and exhaust gas (reforming exhaust gas) Ex used for reforming flows into the space from the opening. The reforming fuel Fr is supplied to the inflowing exhaust gas Ex to form a reforming mixture Gmr. The space functions as a reforming gas mixture 26I for introducing the reforming gas mixture Gmr into the reforming passage 25R of the heat exchange structure 24.

  Further, as shown in FIGS. 2-2, 2-3, and 2-4, the side 24S3 of the heat exchanging structure 24 in which the outlet 25RE of the reforming passage 25R is opened faces the side 24S3. In the space formed between the inner surface 21I of the casing 21, the exhaust gas inlet side sealing means 27I is provided on the exhaust gas introduction section casing 21H side, and the exhaust gas outlet side sealing means 27E is provided on the exhaust gas discharge section casing 21F side. . Thus, the space functions as a reformed gas reservoir 26E in which the reformed gas Exr generated by reforming the reforming gas mixture Gmr with the reforming catalyst in the reforming passage 25R is collected.

  Next, the structure of the heat exchange structure 24 will be described. As shown in FIGS. 3-1 to 3-4, the heat exchange structure 24 is formed with a main exhaust gas passage 25C and a reforming passage 25R. As shown in FIG. 2B, since the heat exchange structure 24 is stored in the housing 21, the main exhaust gas passage 25C provided in the heat exchange structure 24 and the inside of the housing 21 are disposed. The reforming passage 25 </ b> R is stored inside the housing 21.

  Like the heat exchange structure 24 ′ shown in FIG. 3-5, the reforming passage 25R ′ is divided into a plurality of portions in the penetration direction (flow direction of the exhaust gas Ex) of the main exhaust passage 25C ′. The main exhaust gas passage 25C ′ may be divided in the penetration direction of the reforming passage 25R ′ (the flow direction of the reforming mixture Gmr). In this way, since the surface areas of the reforming passage 25R ′ and the main exhaust gas passage 25C ′ can be increased, the heat transfer efficiency from the main exhaust gas passage 25C ′ to the reforming passage 25R ′ can be improved. As a result, the reforming efficiency can be improved.

  In this embodiment, the main exhaust gas passage 25 </ b> C and the reforming passage 25 </ b> R are formed in a common structure and constitute a heat exchange structure 24. By doing so, the strength of the heat exchanging structure 24 can be improved, and assembly is not required, so that the manufacture of the heat exchanging structure 24 can be simplified.

  The exhaust gas introduction housing 21H constituting the housing 21 of the reformer 20 is connected to the exhaust passage 9 (see FIGS. 1, 2-1, and 2-2), and the exhaust gas flowing from the exhaust passage 9 Ex is shunted inside the exhaust gas introduction section housing 21H and distributed to the main exhaust gas passage 25C and the reforming passage 25R. That is, a part of the exhaust gas Ex flowing from the exhaust passage 9 flows into the reforming passage 25R as reforming exhaust gas, and the remaining exhaust gas Ex flows through the main exhaust passage 25C.

  As described above, the exhaust gas introducing unit casing 21H constituting the casing 21 included in the reformer 20 functions as an exhaust gas distributing unit. The reforming exhaust gas Ex is split in the reformer 20, and the exhaust gas Ex that is shunted and used for reforming is an exhaust gas introduction unit housing 21 </ b> H in the reformer 20, and the reformer. The flow path of the reforming exhaust gas Ex can be shortened because it only flows through the reforming gas mixture 26I in 20. As a result, the temperature reduction of the reforming exhaust gas Ex can be suppressed.

  As shown in FIGS. 2-2 and 2-3, the reforming passage 25R is arranged to intersect the main exhaust gas passage 25C. In this embodiment, the reforming passage 25R is orthogonal to the main exhaust gas passage 25C. Note that the angle at which the reforming passage 25R and the main exhaust gas passage 25C intersect (flow passage intersection angle) is not limited to 90 degrees. A reforming catalyst is supported on the inner surface of the reforming passage 25R. Further, exhaust gas Ex is purified on the inner surface of the main exhaust gas passage 25C, the side portion 24S1 of the heat exchanging structure 24 in which the reforming passage 25R is not open, and the inner surface 21I of the casing 21 facing the side portion 24S1. A purifying catalyst is supported. In this embodiment, a three-way catalyst is used as the purification catalyst, but the type of the purification catalyst is not limited to this, and can be appropriately changed depending on the type of the internal combustion engine 1.

  The reforming catalyst carried on the inner surface of the reforming passage 25R is heated by the exhaust gas Ex flowing through the main exhaust gas passage 25C. Further, the reforming catalyst supported on the inner surface of the reforming passage 25R is also heated by the heat generated when the purifying catalyst supported on the inner surface of the main exhaust gas passage 25C purifies the exhaust gas. Furthermore, the temperature drop of the reforming exhaust gas Ex can be suppressed by shortening the path through which the reforming exhaust gas Ex passes. By these actions, the reforming catalyst supported on the inner surface of the reforming passage 25R is efficiently heated, so that the reforming reaction is promoted and hydrogen can be generated efficiently. The production amount also increases.

  Reforming fuel Fr is supplied from the stirring vessel 16 to the reforming gas reservoir 26I (see FIG. 2-2). In order to promote the mixing of the exhaust gas Ex to be reformed and the reforming fuel Fr, the reforming fuel Fr is supplied from the inlet side (internal combustion engine 1 side) of the exhaust gas Ex of the reforming gas reservoir 26I. It is preferable to input. More preferably, it is preferable to introduce the reforming fuel Fr on the exhaust gas Ex inlet side from the opening of the reforming passage 25R of the heat exchange structure 24. In this way, the mixing of the reforming exhaust gas Ex and the reforming fuel Fr is promoted, and a more uniform reforming mixture Gmr is generated, so that the reforming can be performed efficiently.

  In order to input the reforming fuel Fr from the inlet side of the exhaust gas Ex of the reforming gas mixture 26I, the reforming fuel input port 16S from the stirring vessel 16 is connected to the exhaust gas Ex of the reformer 20 as much as possible. Provide on the side. Further, in order to introduce the reforming fuel Fr on the inlet side of the exhaust gas Ex from the opening of the reforming passage 25R of the heat exchange structure 24, the inlet of the exhaust gas Ex from the opening of the reforming passage 25R. A reforming fuel input port 16S is provided on the side. Next, another configuration of the heat exchange structure 24 will be described.

  4A to 4D are perspective views illustrating other configuration examples of the heat exchange structure according to the first embodiment. The structure for heat exchange shown in FIGS. 4-1 to 4-4 constitutes a main exhaust gas passage 25C and a reforming passage 25R by combining a plurality of tubes and a plurality of plates. In the heat exchanging structure 24a shown in FIG. 4A, a plurality of square tubes 28 having an outer cross-sectional shape and a rectangular inner cross-sectional shape are used as the reforming passage 25R. A plate-like member 29 in which a plurality of openings corresponding to the openings of the square tube 28 are formed is attached to the openings at both ends of the square tube 28. That is, the heat exchanging structure 24 a is configured by sandwiching the openings at both ends of the square tube 28 between the two plate-like members 29. A space surrounded by the adjacent square tubes 28 becomes the main exhaust gas passage 25C.

  In the heat exchanging structure 24b shown in FIG. 4B, a plurality of circular pipes 30 whose outer cross-sectional shape and inner cross-sectional shape are rectangular are used as the reforming passage 25R. A plate-like member 31 in which a plurality of openings corresponding to the openings of the circular pipe 30 is formed is attached to the openings at both ends of the circular pipe 30. That is, the heat exchange structure 24 b is configured by sandwiching the opening portions at both ends of the circular tube 30 between the two plate-like members 31. In the heat exchanging structure 24b, the space between the circular tubes 30 becomes the main exhaust gas passage 25C. For this reason, the purification catalyst is carried on the outer surface of the circular tube 30.

  Since this heat exchanging structure 24b can increase the number of circular tubes 30, the heat transfer area of the reforming passage 25R formed inside the circular tube 30 can be increased. As a result, the heat transfer performance is improved, so that the temperature increase rate of the reforming catalyst supported on the reforming passage 25R, that is, the inner surface of the circular tube 30, can be increased, and the reforming efficiency can be improved and the amount of hydrogen generated can be increased. Can be planned. In addition, since the area of the outer surface of the circular tube 30 can be increased, the area on which the purification catalyst is carried can be increased to easily ensure the purification performance.

  In the heat exchange structure 24c shown in FIG. 4C, a plurality of rectangular tubes 32 having an outer cross-sectional shape and a rectangular inner cross-sectional shape are defined as a main exhaust gas passage 25C. A plate-like member 33 in which a plurality of openings corresponding to the openings of the square tube 32 is formed is attached to the openings at both ends of the square tube 32. That is, the heat exchange structure 24 c is configured by sandwiching the opening portions at both ends of the square tube 32 between the two plate-like members 33. A space surrounded by the adjacent square tubes 32 becomes the reforming passage 25R.

  The heat exchanging structure 24d shown in FIG. 4-4 includes a plurality of circular pipes 34 having a circular outer cross-sectional shape and a circular inner cross-sectional shape as the main exhaust gas passage 25C. For this reason, the purification catalyst is carried on the inner surface of the circular tube 34. A plate-like member 35 in which a plurality of openings corresponding to the openings of the circular pipe 34 is formed is attached to the openings at both ends of the circular pipe 34. That is, the heat exchanging structure 24 d is configured by sandwiching the openings at both ends of the circular tube 34 between the two plate-like members 35. In this heat exchange structure 24d, the space between the circular tubes 34 becomes the reforming passage 25R. For this reason, the reforming catalyst is carried on the outer surface of the circular pipe 34.

  Since this heat exchanging structure 24d can increase the number of the circular pipes 34, the heat transfer area of the reforming passage 25R formed between the circular pipes 34 can be increased. As a result, the heat transfer performance is improved, so that the temperature increase rate of the reforming catalyst supported on the outer surface of the reforming passage 25R, that is, the circular pipe 34 can be increased, improving the reforming efficiency and increasing the amount of hydrogen generated. Can be planned. In addition, since the area of the inner surface of the circular tube 34 can be increased, the area on which the purification catalyst is carried can be increased to ensure the purification performance. Next, a reformer according to a modification of the first embodiment will be described.

(Modification)
The reformer according to the modification of the first embodiment is substantially the same as the reformer according to the first embodiment, but in the axial direction of the reformer (a direction parallel to the flow direction of exhaust gas not subjected to reforming). The difference is that the orthogonal cross-sectional shape is elliptical. Other configurations are the same as those of the reformer according to the first embodiment.

  FIG. 5-1 is a cross-sectional view illustrating an exhaust gas reforming apparatus according to a modification of the first embodiment. FIG. 5B is a cross-sectional view taken along the line CC of FIG. As described above, in the reformer 20e according to the modification of the first embodiment, the cross-sectional shape orthogonal to the axis Z direction of the reformer 20e is substantially elliptical. By doing so, the casing 21e of the reforming apparatus 20e can make the ratio of the flat portion to a minimum (no flat portion in this modification), and thus the rigidity of the casing 21e can be improved. As a result, radiated sound from the housing 21e can be reduced.

  In this modification, the reforming passage 25Re formed in the heat exchanging structure 24e included in the reformer 20e is formed so as to be parallel to the long side of the ellipse. In this way, the heat transfer area between the main exhaust gas passage 25Ce and the reforming passage 25Re can be increased, so that the temperature of the reforming catalyst carried on the reforming passage 25Re can be raised faster. And the reforming catalyst can be maintained at a higher temperature. As a result, the reformed gas Exr can be generated more efficiently, and the amount of hydrogen contained in the reformed gas Exr also increases.

  As described above, in this embodiment and the modification thereof, the exhaust gas for reforming is shunted inside the reformer, and the exhaust gas to be used for reforming includes the exhaust gas introduction unit housing in the reformer, and the reformer It only flowed through the reforming gas mixture. As a result, the path through which the reforming exhaust gas passes can be shortened. As a result, since the amount of heat released from the reforming exhaust gas before being introduced into the reforming passage including the reforming catalyst can be suppressed, the temperature reduction of the reforming exhaust gas before being introduced into the reforming passage including the reforming catalyst. Can be suppressed. In addition, as a result of suppressing the temperature drop of the reforming exhaust gas, the reforming catalyst can be easily maintained at a required temperature (activation temperature) or higher, so that the operating range of the reformable internal combustion engine is expanded.

  Furthermore, since the temperature drop of the reforming exhaust gas before being introduced into the reforming passage provided with the reforming catalyst can be suppressed, the temperature drop of the exhaust gas not subjected to reforming is reduced during the reforming. Thereby, when the purification catalyst is disposed downstream of the reformer, the warm-up time of the purification catalyst can be shortened. In addition, by dividing the reforming exhaust gas inside the reformer, the reforming exhaust gas pipe around the outside of the reformer becomes unnecessary, so that the reformer can be made compact. As a result, the mountability on the vehicle is improved. Note that the configurations disclosed in the first embodiment and the modifications thereof can be appropriately applied to the following embodiments.

(Embodiment 2)
The reformer according to Embodiment 2 is substantially the same as the reformer according to Embodiment 1, but before introducing the reforming exhaust gas into the heat exchange structure, the exhaust gas is transferred to the heat exchange structure. The difference is that an exhaust gas guide is provided. Other configurations are the same as those of the reformer according to the first embodiment.

  FIG. 6A is a cross-sectional view illustrating the exhaust gas reforming apparatus according to the second embodiment. FIG. 6B is an enlarged cross-sectional view illustrating a configuration of an exhaust gas guide included in the exhaust gas reforming apparatus according to the second embodiment. The reformer 20f according to this embodiment includes an exhaust gas guide that guides the reformed exhaust gas Ex to the reformed gas mixture 26I on the inlet side of the exhaust gas Ex in the housing 21, that is, on the exhaust gas introduction unit housing 21H side. 36 is provided.

  As shown in FIGS. 6A and 6B, the exhaust gas guide 36 is a plate-like member, and is manufactured by, for example, processing a metal plate into a sheet metal, and the casing 21 by a joining means such as welding. Alternatively, it is attached to at least one of the heat exchange structures 24. As shown in FIG. 6B, the exhaust gas guide 36 is provided so that the exhaust gas outlet side end portion 36et of the exhaust gas guide 36 overlaps the inlet 26Ii of the reforming gas mixture 26I. A passage (introduction passage) 37 that guides the reforming exhaust gas Ex to the reforming passage 25R is formed between the exhaust gas guide 36 and the housing 21 (exhaust gas introduction portion housing 21H).

  In the reforming apparatus 20f according to this embodiment, the introduction passage 37 is provided on the path before the reforming exhaust gas Ex is guided to the reforming gas mixture 26I. Therefore, the reforming exhaust gas Ex is passed through the reforming path 25R. Can lead to sure. Further, it is possible to prevent the exhaust gas Ex to flow into the main exhaust gas passage 25C from being mixed into the reforming gas mixture Gmr flowing into the reforming passage 25R. Furthermore, it is possible to suppress the reforming fuel Fr from flowing into the main exhaust gas passage 25C due to the exhaust pulsation and mixing with the exhaust gas Ex that is not used for reforming, and therefore, wasteful consumption of the reforming fuel Fr can be suppressed. . By these actions, the reforming efficiency can be improved. In addition, since mixing of the reforming fuel Fr and the exhaust gas Ex that is not used for reforming can be suppressed, the exhaust gas having an appropriate air-fuel ratio passes through the main exhaust gas passage 25C, so that a reduction in purification performance can be suppressed.

  The reforming fuel input port 16S from the stirring vessel 16 is preferably provided closer to the exhaust gas inlet 37i side of the introduction passage 37 than the exhaust gas outlet side end portion 36et of the exhaust gas guide 36. Alternatively, the reforming fuel input port 16S from the stirring vessel 16 is preferably provided closer to the exhaust gas inlet 37i side of the introduction passage 37 than the opening of the reforming passage 25R. Thereby, the mixing of the reforming fuel Fr and the reforming exhaust gas Ex is promoted, and a more uniform reforming gas mixture Gmr can be supplied to the reforming passage 25R.

  Further, in this embodiment, a projection 36T is formed in the middle of the exhaust gas guide 36 so as to protrude toward the housing 21 (exhaust gas introduction portion housing 21H), that is, toward the inside of the introduction passage 37. The protrusion 36T is not necessarily provided, but by providing the protrusion 36T, the exhaust gas Ex not subjected to reforming flows into the reforming gas mixture 26I, and the reforming fuel Fr is reformed by the exhaust pulsation. It is possible to more effectively suppress mixing with the exhaust gas Ex that is not supplied to the exhaust gas and the backflow of the reforming exhaust gas Ex toward the main exhaust gas passage 25C due to exhaust pulsation. As a result, the reforming efficiency can be improved, and the deterioration of the gas purification performance can be suppressed.

  As described above, in this embodiment, the reforming exhaust gas is divided into the reformer, and the exhaust gas guide is provided to guide the reforming exhaust gas to the reforming gas mixture. As a result, the temperature reduction of the reforming exhaust gas can be suppressed and the reforming efficiency can be improved. In addition, the exhaust gas guide can suppress the reforming air-fuel mixture and reforming fuel from flowing into the main exhaust gas passage, so that the reforming efficiency can be improved, the amount of hydrogen generation can be increased, and the exhaust gas purification performance Can be suppressed. Note that the configuration disclosed in the second embodiment can be appropriately applied to the following embodiments.

(Embodiment 3)
The exhaust gas reforming system according to Embodiment 3 is substantially the same as the exhaust gas reforming system according to Embodiment 1, but water is further added in the form of water vapor to the exhaust gas to be used for reforming to improve the reforming efficiency. The point to improve is different. Other configurations are the same as those of the reformer according to the first embodiment.

FIG. 7 is an overall configuration diagram of the exhaust gas reforming system according to the third embodiment. In the exhaust gas reforming system 100g shown in FIG. 7, a boiling cooling device 60 that is a steam generating means is provided in the gas cooler 12 that is provided in the gas recirculation passage 10 and cools the reformed gas Exr. The gas cooler 12 is a water-cooled cooler that cools the reformed gas Exr using water (H ₂ O). The boiling cooling device 60 and the gas cooler 12 are a first cooling water passage 63 that returns the water returned to the liquid by the boiling cooling device 60 to the gas cooler 12, and the water that has been heated by the gas cooler 12. It is connected with the 2nd cooling water channel 64 sent to 60. A check valve 66 is provided in the first cooling water passage 63 to prevent the backflow of water from the gas cooler 12 to the boiling cooling device 60.

  When cooling the reformed gas Exr, the boiling cooling device 60 generates steam (steam) for use in reforming by using heat taken by the gas cooler 12 from the reformed gas Exr. The steam obtained by cooling the reformed gas Exr with the gas cooler 12 is stored in the steam reservoir 60 </ b> E of the boiling cooling device 60. The boiling cooling device 60 takes out the steam in the steam reservoir 60 </ b> E from the steam flow rate adjustment valve 62. And the taken-out steam is supplied into the stirring container 16 from the steam supply valve 11 which is a water supply means through the steam supply passage 65, and is used for reforming. The opening degree of the steam flow rate adjustment valve 62 is controlled by the engine ECU 50 in terms of valve opening amount and valve opening time, and the amount of steam supplied into the stirring vessel 16 is controlled.

  The steam that has not been supplied into the stirring vessel 16 is cooled by the cooling unit 60C of the boiling cooling device 60, returned to water, and supplied again to the gas cooler 12 to cool the reformed gas Exr. The cooling unit 60C is cooled by traveling wind, fan wind, or the like, and promotes liquefaction of steam. When steam is supplied into the stirring vessel 16, the amount of water flowing to the gas cooler 12 decreases, and the cooling capacity of the reformed gas Exr decreases. For this reason, the boiling cooling device 60 includes an auxiliary tank 61 for replenishment, and supplies the reduced water supplied to the stirring container 16 from the auxiliary tank 61 to compensate.

  In the exhaust gas reforming system 100g according to this embodiment, steam is generated using the heat of the reformed gas Exr, and this is used for reforming. Thereby, since the heat of evaporation of water can be supplemented by the heat of the reformed gas Exr, the heat used for the evaporation of water can be reduced when water (water vapor) is supplied to the stirring vessel 16. As a result, heat necessary for reforming can be ensured, so that it is possible to increase the amount of hydrogen generated by supplying water and improve reforming efficiency. Further, the heat of the reformed gas Exr can be used effectively. Furthermore, the cooling efficiency of the reformed gas Exr by the gas cooler 12 is improved, and cooling of the gas cooler 12 itself can be expected. Next, a modification of the third embodiment will be described.

(Modification)
The modification of the third embodiment has substantially the same configuration as that of the third embodiment, but the steam supplied to the reforming exhaust gas is generated by a boiling cooling device connected to the cooling means of the stirring vessel for stirring the reforming fuel. The point to do is different. Other configurations are the same as those of the third embodiment.

FIG. 8 is an explanatory diagram illustrating a configuration of a variation of the boiling cooling device provided in the exhaust gas reforming system according to the third embodiment. In the example shown in FIG. 8, a boiling cooling device 60 that is a steam generating means is provided in a water jacket 16W that cools the stirring vessel 16 (see FIG. 7) to which the reforming fuel Fr is supplied. The water jacket 16W is a water-cooled cooler that cools the stirring vessel 16 using water (H ₂ O). The boiling cooling device 60 and the water jacket 16W include the first cooling water passage 63 that returns the water returned to the liquid by the boiling cooling device 60 to the water jacket 16W, and the water heated by the gas cooler 12 to the boiling cooling device 60. It connects with the 2nd cooling water channel 64 to send. A check valve 66 is provided in the first cooling water passage 63 to prevent the back flow of water from the water jacket 16 </ b> W to the boiling cooling device 60.

  When cooling the stirring vessel 16, the boiling cooling device 60 generates steam (steam) to be used for reforming by using the heat taken by the water jacket 16 </ b> W from the stirring vessel 16. The steam obtained by cooling the stirring vessel 16 with the water jacket 16W is stored in the steam reservoir 60E of the boiling cooling device 60. The boiling cooling device 60 takes out the steam in the steam reservoir 60 </ b> E from the steam flow rate adjustment valve 62. And the taken-out steam is supplied into the stirring container 16 from the steam supply valve 11 which is a water supply means through the steam supply passage 65, and is used for reforming. The opening degree of the steam flow rate adjustment valve 62 is controlled by the engine ECU 50 in terms of valve opening amount and valve opening time, and the amount of steam supplied into the stirring vessel 16 is controlled.

  The steam that has not been supplied into the stirring vessel 16 is cooled by the cooling unit 60C of the boiling cooling device 60, returned to water, and supplied again to the gas cooler 12 to cool the reformed gas Exr. The cooling unit 60C is cooled by traveling wind, fan wind, or the like, and promotes liquefaction of steam. When steam is supplied into the stirring vessel 16, the amount of water flowing to the gas cooler 12 decreases, and the cooling capacity of the reformed gas Exr decreases. For this reason, the boiling cooling device 60 is provided with an auxiliary tank 61 for replenishment, and supplements the reduced water supplied from the auxiliary tank 61 by supplying it to the stirring vessel 16. Also in this modification, the same operation and effect as the exhaust gas reforming system according to Embodiment 3 can be obtained. Further, since the cooling efficiency of the stirring vessel 16 is improved, the reforming fuel injection valve 2 can be cooled more effectively, and the durability can be more effectively suppressed.

  As mentioned above, in this embodiment and its modification, since the steam is generated using the heat of the reformed gas and used for reforming, the heat used for water evaporation can be reduced. As a result, heat necessary for reforming can be secured, so that the amount of hydrogen generated by supplying water can be increased and the reforming efficiency can be improved. Further, the heat of the reformed gas Exr can be used effectively. In addition, the cooling efficiency of the reformed gas and the like is improved.

  As described above, the exhaust gas reforming apparatus and the exhaust gas reforming system according to the present invention are useful for exhaust gas reforming in which fuel is supplied to exhaust gas to generate reformed gas containing hydrogen. It is suitable for suppressing the temperature drop of the exhaust gas to be provided.

1 is an overall configuration diagram of an exhaust gas reforming system according to Embodiment 1. FIG. 1 is a perspective view showing an exhaust gas reforming apparatus according to Embodiment 1. FIG. 1 is a cross-sectional view showing an exhaust gas reforming apparatus according to Embodiment 1. FIG. It is AA arrow line view of FIG. It is a BB arrow line view of Drawing 2-2. It is a perspective view which shows the structure for heat exchange with which the exhaust gas reforming apparatus which concerns on Embodiment 1 is provided. It is a front view which shows the structure for heat exchange with which the exhaust gas reforming apparatus which concerns on Embodiment 1 is provided. It is a top view which shows the structure for heat exchange with which the exhaust gas reforming apparatus which concerns on Embodiment 1 is provided. It is a side view which shows the structure for heat exchange with which the exhaust gas reforming apparatus which concerns on Embodiment 1 is provided. It is a partial perspective view which shows the other example of the structure for heat exchange with which the exhaust gas reforming apparatus which concerns on Embodiment 1 is provided. FIG. 6 is a perspective view illustrating another configuration example of the heat exchange structure according to the first embodiment. FIG. 6 is a perspective view illustrating another configuration example of the heat exchange structure according to the first embodiment. FIG. 6 is a perspective view illustrating another configuration example of the heat exchange structure according to the first embodiment. FIG. 6 is a perspective view illustrating another configuration example of the heat exchange structure according to the first embodiment. It is sectional drawing which shows the exhaust gas reforming apparatus which concerns on the modification of Embodiment 1. It is CC sectional drawing of FIGS. It is sectional drawing which shows the exhaust gas reforming apparatus which concerns on Embodiment 2. FIG. It is an expanded sectional view which shows the structure of the exhaust gas guide with which the exhaust gas reforming apparatus which concerns on Embodiment 2 is provided. It is a whole block diagram of the exhaust gas reforming system which concerns on Embodiment 3. It is explanatory drawing which shows the structure of the modification of the boiling cooling device with which the exhaust gas reforming system which concerns on Embodiment 3 is provided.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Reforming fuel injection valve 3 Intake passage 5 Recirculation flow rate adjustment valve 9 Exhaust passage 10 Gas recirculation passage 11 Steam supply valve 12 Gas cooler 13 Air cleaner 14 Pulsation reduction container 15 Check valve 16 Stirring container 16W Water jacket 16S Reforming fuel inlet 20, 20e, 20f Reforming device (exhaust gas reforming device)
21, 21e Housing 21B Body 21F Exhaust gas discharge housing 21H Exhaust gas introduction housing 21I Inner surface 24, 24 ', 24a, 24b, 24c, 24d, 24e Heat exchange structure 25R, 25Re reforming passage 25C, 25Ce Main exhaust gas passage 26E Reformed gas reservoir 26I Reforming mixture reservoir 27E Exhaust gas outlet side sealing means 27I Exhaust gas inlet side sealing means 36 Exhaust gas guide 36T Projection 36et Exhaust gas outlet side end portion 37 Introductory passage 50 Engine ECU
60 Boiling cooler 61 Auxiliary tank 62 Steam flow rate adjustment valve 65 Steam supply passage 66 Check valve 100, 100 g Exhaust gas reforming system

Claims (11)

A reformed gas containing hydrogen produced by reforming an air-fuel mixture of fuel and exhaust gas discharged from the internal combustion engine with a reforming catalyst is recirculated to the intake passage of the internal combustion engine;
A main exhaust gas passage through which the exhaust gas passes;
Inside, the reforming catalyst is provided, and is disposed so as to intersect with the main exhaust gas passage, and a reforming passage through which a part of the exhaust gas discharged from the internal combustion engine passes,
A housing that houses the main exhaust gas passage and the reforming passage;
An exhaust gas distribution unit that divides the exhaust gas discharged from the internal combustion engine inside the housing on the exhaust gas inlet side, and distributes the exhaust gas to the main exhaust gas passage and the reforming passage;
An exhaust gas reforming apparatus comprising:   The exhaust gas reforming apparatus according to claim 1, wherein a purification catalyst for purifying the exhaust gas is provided inside the main exhaust gas passage.   The exhaust gas reforming apparatus according to claim 1 or 2, wherein the casing is cylindrical.   An exhaust gas guide for introducing the exhaust gas into the reforming passage is provided in the exhaust gas distribution portion on the exhaust gas inlet side of the reforming passage, and the reforming is provided between the exhaust gas guide and the casing. The exhaust gas reforming apparatus according to any one of claims 1 to 3, wherein a passage for guiding the exhaust gas to the passage is formed.   The exhaust gas reformer according to claim 4, wherein the exhaust gas guide is provided with a protrusion protruding toward the housing. Moisture supply means for supplying moisture to the exhaust gas flowing into the reforming passage;
A boiling cooling device that generates steam using the heat of the gas cooling means that cools the reformed gas and then recirculates to the intake passage, and supplies the steam to the moisture supply means;
The exhaust gas reforming apparatus according to any one of claims 1 to 5, wherein the exhaust gas reforming apparatus is provided. A stirring vessel into which the fuel is injected;
The exhaust gas reforming apparatus according to any one of claims 1 to 6, wherein the fuel is supplied to the exhaust gas flowing into the reforming passage after being injected into the stirring vessel.   The exhaust gas reforming apparatus according to claim 7, wherein the boiling cooling device generates steam by using heat of at least one of the gas cooling means or the stirring vessel. An internal combustion engine;
The exhaust gas reforming apparatus according to any one of claims 1 to 8, provided in the middle of an exhaust gas passage through which exhaust gas discharged from the internal combustion engine flows.
A gas recirculation passage for recirculating the reformed gas generated by the exhaust gas reformer to the intake passage of the internal combustion engine;
A reflux flow rate adjusting means provided between the exhaust gas reforming device and the intake passage;
An exhaust gas reforming system comprising:   The pulsation reduction container for reducing the pulsation of the reformed gas is provided in the middle of the gas recirculation passage and between the exhaust gas reformer and the recirculation flow rate adjusting means. Exhaust gas reforming system.   A check valve is provided in the middle of the gas recirculation passage and between the exhaust gas reforming device and the pulsation reducing container to suppress the flow of the reformed gas toward the exhaust gas reforming device. The exhaust gas reforming system according to claim 10.

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