JP2015121151A - Internal combustion engine system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine system capable of reducing or curbing performance degradation of a reforming catalyst due to oxidation.SOLUTION: An internal combustion engine system comprises: an internal combustion engine which has a combustion chamber, an air intake passage and an exhaust passage connected to the combustion chamber, and an exhaust circulation passage connected to the exhaust passage and the air intake passage; a fuel supply device which supplies reforming fuel to an inside of the exhaust circulation passage; and a reformer which is arranged in the exhaust circulation passage and has a reforming catalyst generating reformed gas including hydrogen through a reforming reaction by using exhaust in the exhaust circulation passage and the reforming fuel. The internal combustion engine system performs: an oxidative regeneration treatment supplying oxidation gas to a carbon component generated on the reforming catalyst through the reforming reaction; and a reductive regeneration treatment supplying reducing gas to an oxidative component generated on the reforming catalyst through the oxidative regeneration treatment.

Description

  The present invention relates to an internal combustion engine system. More specifically, the present invention relates to an internal combustion engine system that can suppress or prevent a performance degradation of a reforming catalyst in a reformer disposed in an exhaust gas circulation passage.

  Conventionally, there has been proposed an internal combustion engine system that can realize a longer life of a reforming catalyst without detecting degradation or deterioration of the performance of the reforming catalyst (see Patent Document 1). This internal combustion engine system includes an internal combustion engine having an exhaust circulation path for circulating exhaust gas from a combustion chamber to an intake path, and reforming fuel injection for injecting reforming fuel into the exhaust gas flowing through the exhaust circulation path A reformer provided with a reforming catalyst for generating a hydrogen-containing gas from the reforming fuel, and opening the exhaust circuit at every predetermined regeneration timing of the reforming catalyst to convert the oxygen-containing gas into the reforming catalyst. And reforming catalyst regeneration means for regenerating the reforming catalyst by oxidizing the carbon that is circulated and deposited on the reforming catalyst with oxygen in the exhaust gas.

JP 2012-188963 A

  However, in the internal combustion engine system described in Patent Document 1, since the oxygen-containing gas is circulated through the exhaust circulation path and regeneration is performed by oxidation removal of the carbon component deposited on the reforming catalyst, the surface of the reforming catalyst As a result, the performance of the reforming catalyst deteriorates, and there is room for improvement in that the desired reformed gas may not be obtained when the operation of the internal combustion engine is resumed.

  The present invention has been made in view of such problems of the prior art. Then, an object of the present invention is to provide an internal combustion engine system that can suppress or prevent performance degradation due to oxidation of the reforming catalyst.

  The inventors of the present invention have made extensive studies in order to achieve the above object. As a result, an oxidation regeneration process for supplying an oxidizing gas to the carbon component generated by the reforming reaction is performed on the reforming catalyst, and a reducing gas is supplied to the oxidizing component generated by the oxidation regeneration process on the reforming catalyst. It has been found that the above-described object can be achieved by carrying out reduction regeneration treatment, and the present invention has been completed.

  That is, an internal combustion engine system of the present invention includes an internal combustion engine having a combustion chamber, an intake passage and an exhaust passage connected to the combustion chamber, an exhaust passage and an exhaust circulation passage connected to the intake passage, A fuel supply device for supplying reforming fuel into the circulation channel, and a reformer that is disposed in the exhaust circulation channel and contains hydrogen by a reforming reaction that uses the exhaust gas in the exhaust circulation channel and the reforming fuel. And a reformer having a reforming catalyst for generating a quality gas. The internal combustion engine system performs an oxidation regeneration process for supplying an oxidizing gas to the carbon component generated by the reforming reaction on the reforming catalyst, and a reducing gas for the oxidizing component generated by the oxidation regeneration process on the reforming catalyst. Reduction regeneration processing is performed to supply.

  According to the present invention, an internal combustion engine having a combustion chamber, an intake passage connected to the combustion chamber, an exhaust passage, an exhaust passage and an exhaust circulation passage connected to the intake passage, A reformer containing hydrogen is generated by a reforming reaction that uses the exhaust gas in the exhaust circulation passage and the reforming fuel. And a reformer having a reforming catalyst for performing an oxidation regeneration process for supplying an oxidizing gas to a carbon component generated by a reforming reaction on the reforming catalyst, and generating by an oxidation regeneration process on the reforming catalyst. The reduction regeneration process for supplying the reducing gas to the oxidizing component is performed. Therefore, it is possible to provide an internal combustion engine system that can suppress or prevent performance degradation due to oxidation of the reforming catalyst.

FIG. 1 is an explanatory diagram illustrating an outline of the internal combustion engine system according to the first embodiment. FIG. 2 is a graph illustrating a method for supplying a reducing gas in the internal combustion engine system of each example. FIG. 3 is an explanatory diagram illustrating an outline of the internal combustion engine system according to the second embodiment. FIG. 4 is an explanatory diagram showing an outline of the internal combustion engine system of the third embodiment.

  Hereinafter, an internal combustion engine system according to an embodiment of the present invention will be described in detail.

(First embodiment)
An internal combustion engine system according to a first embodiment includes an internal combustion engine having a combustion chamber, an intake passage connected to the combustion chamber, an exhaust passage, an exhaust passage, and an exhaust circulation passage connected to the intake passage. A fuel supply device for supplying reforming fuel into the exhaust circulation passage, and hydrogen that is provided in the exhaust circulation passage, and reforming reaction using the exhaust in the exhaust circulation passage and the reforming fuel. And a reformer having a reforming catalyst that generates reformed gas. The internal combustion engine system of the present embodiment performs an oxidation regeneration process for supplying an oxidizing gas to the carbon component generated by the reforming reaction on the reforming catalyst, and an oxidation component generated by the oxidation regeneration process on the reforming catalyst. A reduction regeneration process for supplying a reducing gas is performed.

  Thus, the internal combustion engine having the combustion chamber, the intake passage connected to the combustion chamber, the exhaust passage, the exhaust passage and the exhaust circulation passage connected to the intake passage, and the exhaust circulation passage are modified. A fuel supply device for supplying quality fuel and a reformer that is disposed in the exhaust circulation passage and generates reformed gas containing hydrogen by a reforming reaction that uses the exhaust gas in the exhaust circulation passage and the reforming fuel. A reformer having a catalyst, and an oxidation regeneration process for supplying an oxidizing gas to a carbon component generated by a reforming reaction on the reforming catalyst, and an oxidation generated by an oxidation regeneration process on the reforming catalyst. By performing a reduction regeneration process that supplies reducing gas to the components, it is possible to reduce and regenerate the oxidation components that are generated on the reforming catalyst during the oxidation regeneration process, so that the hydrogen generation ability of the reforming catalyst is restored. Reduces the performance degradation due to reforming catalyst oxidation It is possible to prevent stone. Moreover, since the desired reformed gas can be obtained, the fuel efficiency of the internal combustion engine system can be improved.

  In the present embodiment, for example, it is preferable to perform reduction regeneration processing when the internal combustion engine is started. By performing the reduction regeneration process when the internal combustion engine is started, the recovery of the hydrogen generation ability of the reforming catalyst is accelerated, and the performance degradation due to the oxidation of the reforming catalyst is suppressed or prevented. The reformed gas can be obtained.

  In the present embodiment, for example, it is preferable to perform the reduction regeneration process when the exhaust gas circulation in the internal combustion engine is started. When the exhaust gas circulation in the internal combustion engine is started, the reduction regeneration treatment is performed, so that the recovery of the hydrogen generation ability of the reforming catalyst is accelerated, and the performance degradation due to the oxidation of the reforming catalyst is suppressed or prevented. A desired reformed gas can be obtained immediately after the start of exhaust gas circulation.

  Furthermore, in the present embodiment, for example, when the reforming reaction in the reformer is started, it is preferable to perform the reduction regeneration process. By performing the reduction regeneration process when the reforming reaction in the reformer is started, the hydrogen generation ability of the reforming catalyst is quickly recovered, and the performance deterioration due to the oxidation of the reforming catalyst is suppressed or prevented. The desired reformed gas can be obtained immediately after the start of the reforming reaction in the mass device.

  Further, in the present embodiment, for example, at least one of an oxidizing gas whose oxygen concentration is higher than that of the oxidizing gas supplied in the oxidation regeneration process and an oxidizing gas supplied in a larger amount than the oxidizing gas supplied in the oxidation regeneration process. It is preferable to perform an emergency reduction regeneration process in which a reducing gas is supplied to the oxidizing component produced on the reforming catalyst when exposed to the catalyst. Emergency reduction regeneration when the reforming catalyst is exposed to at least one of an oxidizing gas having a higher oxygen concentration than the oxidizing gas supplied in the oxidation regeneration process and an oxidizing gas supplied in a larger amount than the oxidizing gas supplied in the oxidation regeneration process By performing the treatment immediately, the hydrogen production ability of the reforming catalyst can be quickly recovered, the performance degradation due to the oxidation of the reforming catalyst can be suppressed or prevented, and the desired reformed gas can be obtained immediately after the emergency reduction regeneration treatment. it can.

  Furthermore, in the present embodiment, for example, the supply amount of the reducing gas is preferably a fixed value. By carrying out reduction regeneration treatment of the reforming catalyst with the supply amount of reducing gas as a fixed value, the recovery of the hydrogen generation ability of the reforming catalyst can be accelerated, and the performance degradation due to oxidation of the reforming catalyst can be suppressed or prevented. In particular, it is not necessary to control the supply amount of the reformed gas, and the reduction regeneration process can be easily performed.

  On the other hand, in the present embodiment, for example, the supply amount of the reducing gas is preferably a variable value. By performing the reduction regeneration process according to the environment where the reforming catalyst is exposed with the supply amount of the reducing gas as a variable value, the hydrogen generation ability of the reforming catalyst is quickly recovered, and the performance is reduced due to the oxidation of the reforming catalyst. If this can be suppressed or prevented, the reduction regeneration process can be performed more reliably and without waste.

  Further, in the present embodiment, when the supply amount of the reducing gas is set to a variable value, for example, it is preferable to set the variable value to be set according to the operating load of the internal combustion engine. By performing the reduction regeneration process by setting the supply amount of the reducing gas according to the operating load of the internal combustion engine, the reduction regeneration process can be performed according to the ease with which the reforming catalyst is regenerated.

  Furthermore, when the supply amount of the reducing gas is set to a variable value in the present embodiment, for example, it is preferable to set a variable value that is set according to the exhaust gas circulation rate in the internal combustion engine. By performing the reduction regeneration process by setting the supply amount of the reducing gas according to the exhaust gas circulation rate in the internal combustion engine, the reduction regeneration process capable of promptly shifting to the reforming reaction in the reformer can be performed.

(Second Embodiment)
Further, the internal combustion engine system according to the second embodiment is different from the internal combustion engine system according to the first embodiment in that a reformed catalyst reduction / regeneration device that performs a reduction regeneration process is separately provided. Since the reduction regeneration process is performed by the reforming catalyst reduction regeneration apparatus provided separately, there is an advantage that the reduction regeneration process can be performed under any circumstances. Moreover, since the desired reformed gas can be obtained, the fuel efficiency of the internal combustion engine system can be improved.

(Third embodiment)
Further, in the internal combustion engine system according to the third embodiment, the fuel supply device supplies more reducing gas than the reducing gas supply amount set in accordance with the operating load of the internal combustion engine and the exhaust gas circulation rate in the internal combustion engine. Thus, the configuration for supplying the reforming fuel and performing the reduction regeneration process is different from the internal combustion engine system according to the first embodiment. The reduction regeneration process is performed by causing the fuel supply device to supply reforming fuel so as to supply more reducing gas than the amount of reducing gas supplied that is set according to the operating load of the internal combustion engine and the exhaust gas circulation rate in the internal combustion engine. By performing this, there is an advantage that the reduction regeneration process can be performed without the necessity of separately providing a reforming catalyst reduction regeneration apparatus (for example, a hydrogen cylinder or the like). Moreover, since the desired reformed gas can be obtained, the fuel efficiency of the internal combustion engine system can be improved.

(Fourth embodiment)
The internal combustion engine system according to the fourth embodiment further includes a partial oxidation reaction air supply device that supplies partial oxidation reaction air into the exhaust circulation passage, and the reforming fuel supplied by the fuel supply device When the partial oxidation reaction is caused to occur by using the air supplied by the partial oxidation reaction air supply device, the structure for performing the reduction regeneration treatment by reducing the supply of the reforming fuel intermittently and step by step, This is different from the internal combustion engine system according to the first embodiment. A partial oxidation reaction air supply device for supplying partial oxidation reaction air into the exhaust circulation channel is separately provided, and the reforming fuel supplied by the fuel supply device and the air supplied by the partial oxidation reaction air supply device are used. Then, when the partial oxidation reaction is caused, the reduction regeneration process is performed by reducing the supply of the reforming fuel to the fuel supply apparatus intermittently and stepwise, thereby performing the reforming catalyst reduction regeneration apparatus (for example, There is an advantage that reduction regeneration treatment can be performed even when the temperature of the reforming catalyst is low. Moreover, since the desired reformed gas can be obtained, the fuel efficiency of the internal combustion engine system can be improved.

  Furthermore, in the present embodiment, it is preferable that the partial oxidation reaction air supply device performs oxidation regeneration treatment. By performing the oxidation regeneration process using the partial oxidation reaction air supply device, there is an advantage that the oxidation regeneration process can be performed regardless of the operating state of the internal combustion engine.

(Fifth embodiment)
Further, the internal combustion engine system according to the fifth embodiment is different from the internal combustion engine system according to the first embodiment in that a reforming catalyst oxidation regeneration device that performs oxidation regeneration processing is separately provided. The configuration in which the oxidation regeneration process is performed by the separately provided reforming catalyst oxidation regeneration apparatus has an advantage that the oxidation regeneration process can be performed regardless of the operating state of the internal combustion engine. Moreover, since the desired reformed gas can be obtained, the fuel efficiency of the internal combustion engine system can be improved.

  Hereinafter, an internal combustion engine system of the present invention will be described in detail based on some embodiments with reference to the drawings.

Example 1
FIG. 1 is an explanatory diagram illustrating an outline of the internal combustion engine system according to the first embodiment. As shown in FIG. 1, the internal combustion engine system 1 </ b> A of the present example includes a four-cycle engine 10 that is an example of a reciprocating internal combustion engine, a fuel supply device 20, and a reformer 30.

  The engine 10 includes a combustion chamber 11, an intake passage (hereinafter referred to as “intake pipe”) 12 connected to the intake port 11 a of the combustion chamber 11, and an exhaust passage connected to the exhaust port 11 b of the combustion chamber 11. (Hereinafter referred to as “exhaust pipe”) 13 and an exhaust circulation passage (hereinafter referred to as “exhaust pipe”) for connecting a part of the exhaust gas from the exhaust pipe 13 to the intake pipe 12, that is, refluxing. EGR (Exhaust Gas Recirculation) pipe ”) 14. Further, the engine 10 diverts a part of the exhaust gas that has been stoichiometrically combusted in the combustion chamber 11 from the exhaust pipe 13 to the EGR pipe 14, adds reforming fuel to the exhaust gas by the fuel injection device 20, and the reformer 30. Thus, the reforming fuel can be reformed into reformed gas containing hydrogen and recirculated to the intake pipe 12.

  Further, the engine 10 includes an intake valve 11c that opens and closes the intake port 11a, an exhaust valve 11d that opens and closes the exhaust port 11b, a piston 11e that reciprocates in the combustion chamber 11, and an air-fuel mixture in the combustion chamber 11. A spark plug 11f that displaces electric sparks is disposed.

  Further, the intake pipe 12 is provided with a main fuel supply device 12a in the vicinity of the intake port 11a, and the air flowing in the intake pipe 12 toward the combustion chamber 11 on the upstream side in the intake direction of the main fuel supply device 12a. An intake control valve 12b for controlling the amount of air is further provided. Here, the main fuel supply device 12 a has a function of injecting main fuel into the combustion chamber 11 or the intake pipe 12.

  Further, the exhaust pipe 13 is provided with an exhaust control valve 13 a for controlling the exhaust amount of the exhaust flowing through the exhaust pipe 13.

  Further, the EGR pipe 14 includes a fuel supply device 20 that supplies reforming fuel into the EGR in a direction from the upstream side to the downstream side in the exhaust gas flow direction (indicated by an arrow α in the figure). A reformer 30 having a quality catalyst, an EGR cooler 14b, and an EGR valve 14c are sequentially arranged. The reforming fuel may be the same as or different from the main fuel. Here, the reforming catalyst generates reformed gas containing hydrogen by a reforming reaction using the exhaust gas in the EGR pipe 14 and the reforming fuel. Typically, it has a function of reacting the reforming fuel and at least a part of the exhaust, and reforming the fuel to generate a reformed gas containing hydrogen, such as a noble metal, more specifically May include rhodium. Normally, since exhaust contains heat and moisture, the reforming catalyst promotes at least one of a thermal decomposition reaction, a steam reforming reaction, and a water gas shift reaction by adding a reforming fuel, and hydrogen. The reformed gas containing is generated. The EGR cooler 14b has a function of cooling exhaust gas and reformed gas. The EGR valve 14c has a function of controlling the flow rate of exhaust gas and reformed gas.

  Further, in this example, the EGR pipe 14 is reduced to the oxidation component generated by the oxidation regeneration process on the reforming catalyst, upstream of the reformer 30 in the exhaust gas flow direction (indicated by arrow α in the figure). A reforming catalyst reduction and regeneration device 14a that performs a reduction and regeneration process for supplying gas is provided.

  Furthermore, the controller 40 including a central processing unit (CPU), an interface circuit, and the like includes a main fuel supply device 12a, an intake control valve 12b, an exhaust control valve 13a, a fuel supply device 20, an EGR valve 14c, a reforming catalyst reduction regeneration device. 14a, and further connected to a control unit (not shown) such as an intake valve 11c, an exhaust valve 11d, and a piston 11e, inputs / outputs signals related to control, and operates them appropriately by executing a predetermined program. It has become.

  On the reforming catalyst of the reformer 30, while reformed gas containing hydrogen is obtained from the reforming fuel by a reforming reaction, a part of the reformed gas may be generated (deposited) as a carbon component.

  Therefore, in the internal combustion engine system 1A of the present example, for example, the supply of the reforming fuel by the fuel injection device 20 is stopped and the oxidizing gas such as oxygen contained in the exhaust gas stoichiometrically combusted in the combustion chamber 11 is modified. Oxidation regeneration treatment can be performed by supplying the carbon component on the catalyst. Furthermore, in the internal combustion engine system 1A of this example, the reforming catalyst reduction regeneration device 14a can perform the reduction regeneration process by supplying the reducing gas to the oxidation component generated by the oxidation regeneration process on the reforming catalyst. .

  In this way, the oxidation regeneration process for supplying the oxidizing gas to the carbon component generated by the reforming reaction is performed on the reforming catalyst, and the reducing gas is supplied to the oxidizing component generated by the oxidation regeneration process on the reforming catalyst. By adopting a regenerative treatment configuration, the hydrogen generation ability of the reforming catalyst can be quickly recovered, and performance degradation due to oxidation of the reforming catalyst can be suppressed or prevented without detecting degradation or deterioration of the performance of the reforming catalyst. be able to. Moreover, since the desired reformed gas can be obtained, the fuel efficiency of the internal combustion engine system can be improved. However, since the reforming catalyst has low reforming performance, it takes time to reduce the oxidizing component produced on the reforming catalyst with a small amount of hydrogen generated by the reforming catalyst itself, and the performance is reduced. It goes without saying that the decline can be recovered.

  More specifically, the process in which the deposited carbon is oxidized will be described. The carbon component deposited on the catalyst is oxidized at a temperature higher than the temperature at which the oxidation reaction can proceed and is supplied with oxygen at a certain concentration or higher. Desorbed from the catalyst surface in the state of carbon or oxygen monoxide. At that time, since the catalyst surface is exposed to the oxygen-containing gas at a high temperature, the catalyst surface is oxidized. Note that the oxidation temperature and the required oxygen concentration vary depending on the catalyst specifications.

  Further, the process of reducing the catalyst surface will be described more specifically. The catalyst surface is reduced by supplying a reducing component to the catalyst surface oxidized by the above process at a certain temperature or higher. As the reducing component, hydrogen is desirable, but a hydrocarbon capable of generating hydrogen can be substituted. Similarly to the oxidation, the reducible temperature and the hydrogen concentration necessary for the reduction vary depending on the catalyst specifications.

  Further, in the internal combustion engine system 1A of this example, for example, at any time such as when the internal combustion engine is started, when exhaust gas circulation in the internal combustion engine is started, or when a reforming reaction is started in the reformer. Reduction regeneration processing can be performed. Here, the timing at which the internal combustion engine is started can be determined by a signal input to the controller 40 from the main fuel supply device 12a, the intake control valve 12b, the intake valve 11c, the piston 11e, and the like. Further, the timing at which exhaust gas circulation in the internal combustion engine is started can be determined by a signal input from the exhaust control valve 13a to the controller 40, for example. Furthermore, the timing at which the reforming reaction in the reformer is started can be determined by, for example, a signal input from the fuel supply device 20 to the controller 40. Since the reforming catalyst and the atmospheric temperature are high at the timing when exhaust gas circulation is started, the reduction regeneration process can be performed in a shorter time. The timing at which the reforming reaction is started in the reformer is, for example, in the internal combustion engine system 1A of this example, in which the temperature sensor 14d indicated by a broken line is disposed in the reformer 30, and the controller 40 and the temperature sensor are connected. When connected (not shown) and configured to input and output signals relating to control, it can also be determined by a signal input to the controller 40 from the temperature sensor 14d. Since the reforming catalyst and the atmospheric temperature are higher at the timing when the reforming reaction is started, the reduction regeneration process can be performed in a shorter time. In addition, when the reduction regeneration process is performed at this time, there is an advantage that it is possible to shift directly to the EGR reforming operation in which reforming is performed in the reformer.

  Further, in the internal combustion engine system 1A of the present example, for example, the oxygen sensor 14e indicated by a broken line is disposed in the reformer 30, the controller 40 and the oxygen sensor 14e are connected (not shown), and signals relating to control are transmitted. When the input / output is configured, the reforming catalyst has at least an oxidizing gas having a higher oxygen concentration than the oxidizing gas supplied in the oxidation regeneration process and an oxidizing gas supplied in a larger amount than the oxidizing gas supplied in the oxidation regeneration process. It is also possible to determine the timing of exposure to one by a signal input from the oxygen sensor 14e to the controller 40 and perform an emergency reduction regeneration process for supplying a reducing gas to an oxidizing component generated on the reforming catalyst. For example, even during the EGR reforming operation, when suddenly exposed to a predetermined oxidizing gas, the reducing gas can be urgently supplied to the oxidizing component generated on the reforming catalyst. Recovery of the hydrogen generation ability of the reforming catalyst is accelerated, and performance degradation due to oxidation of the reforming catalyst can be suppressed or prevented without detecting performance degradation / degradation of the reforming catalyst.

  Further, in the internal combustion engine system 1A of this example, the supply amount of the reducing gas may be any supply amount that can reduce the surface of the reforming catalyst. For example, as shown in FIG. A certain amount may be supplied for a certain time. Moreover, you may supply with a variable value. Further, in the internal combustion engine system 1A of this example, a variable value set in accordance with the operating load of the internal combustion engine as shown in FIG. 2 (B) and the exhaust gas circulation rate in the internal combustion engine as shown in FIG. 2 (C). It is good. In this case, the reforming catalyst surface can be reliably reduced without waste. In some cases, a temperature of a certain level or more is required for the reduction of the catalyst surface. In that case, reducing gas such as hydrogen supplied at a certain temperature or less does not contribute to the reduction of the reforming catalyst surface, and more reducing gas such as hydrogen is required until the reduction of the reforming catalyst surface is completed. Need to be supplied. Therefore, it is preferable to supply a reducing gas such as hydrogen according to the operating load of the internal combustion engine and the exhaust gas circulation rate. That is, if the operating load of the internal combustion engine is known, the exhaust gas temperature can be estimated, and it can be determined whether or not the reforming catalyst surface is at a reducible temperature. When the operating load of the internal combustion engine is not more than a certain load, the reduction gas such as hydrogen for reduction regeneration treatment is not supplied, and when the operation load is more than a certain load, the reduction gas such as hydrogen for reduction regeneration treatment is not supplied. Supply. In addition, the higher the temperature of the reforming catalyst, the faster the reduction regeneration speed. Therefore, if the required amount of hydrogen can be supplied, the reduction regeneration surface of the reforming catalyst surface can be performed in a shorter time. Therefore, it is preferable to change the supply amount of the reducing gas according to the operation load of the internal combustion engine. The fixed value may be set in advance by a preliminary experiment according to each configuration of the internal combustion engine system, and the variable value also depends on each configuration of the internal combustion engine system, the operating load of the internal combustion engine, and the exhaust gas circulation rate of the internal combustion engine. Thus, a map that can be set in advance by a preliminary experiment may be set.

(Example 2)
FIG. 3 is an explanatory diagram illustrating an outline of the internal combustion engine system according to the second embodiment. In addition, about the structure same as Example 1, the overlapping description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  As shown in FIG. 3, the fuel reforming system 1B of this example has a reforming catalyst reduction regeneration upstream of the reformer 30 of the EGR pipe 14 in the exhaust gas flow direction (indicated by an arrow α in the figure). The device 14a is not provided, and the fuel supply device 20 is modified so as to supply more reducing gas than the amount of reducing gas supplied that is set according to the operating load of the internal combustion engine and the exhaust gas circulation rate in the internal combustion engine. The configuration for supplying the quality fuel and performing the reduction regeneration process is different from the internal combustion engine system of the first embodiment. Although not shown, a reforming catalyst reduction regeneration device 14a may be separately provided.

  In this way, the oxidation regeneration process for supplying the oxidizing gas to the carbon component generated by the reforming reaction is performed on the reforming catalyst, and the reducing gas is supplied to the oxidizing component generated by the oxidation regeneration process on the reforming catalyst. By adopting a regenerative treatment configuration, the hydrogen generation ability of the reforming catalyst can be quickly recovered, and performance degradation due to oxidation of the reforming catalyst can be suppressed or prevented without detecting degradation or deterioration of the performance of the reforming catalyst. be able to. Moreover, since the desired reformed gas can be obtained, the fuel efficiency of the internal combustion engine system can be improved. When supplying reforming fuel capable of generating hydrogen instead of hydrogen, if the temperature of the reforming catalyst is too low, carbon deposition may occur. Therefore, depending on the operating load of the internal combustion engine and the exhaust gas circulation rate of the internal combustion engine, as shown in FIG. It is preferable to supply to. In particular, in the internal combustion engine system of the present example, when the reducing gas necessary for the reduction regeneration process is supplied by supplying the reforming fuel more excessively than during the normal EGR reforming operation, the fuel from the fuel supply device 20 By changing the supply amount, it is possible to quickly shift to the EGR reforming operation.

  More specifically, the process in which the deposited carbon is oxidized will be described. The carbon component deposited on the catalyst is oxidized at a temperature higher than the temperature at which the oxidation reaction can proceed and is supplied with oxygen at a certain concentration or higher. Desorbed from the catalyst surface in the state of carbon or oxygen monoxide. At that time, since the catalyst surface is exposed to the oxygen-containing gas at a high temperature, the catalyst surface is oxidized. Note that the oxidation temperature and the required oxygen concentration vary depending on the catalyst specifications.

  Further, the process of reducing the catalyst surface will be described more specifically. The catalyst surface is reduced by supplying a reducing component to the catalyst surface oxidized by the above process at a certain temperature or higher. As the reducing component, hydrogen is desirable, but a hydrocarbon capable of generating hydrogen can be substituted. Similarly to the oxidation, the reducible temperature and the hydrogen concentration necessary for the reduction vary depending on the catalyst specifications.

  Further, in the internal combustion engine system 1B of the present example, for example, at any time such as when the internal combustion engine is started, when exhaust gas circulation in the internal combustion engine is started, or when a reforming reaction is started in the reformer. Although reduction regeneration processing can be performed, from the viewpoint of high exhaust temperature, the reduction regeneration processing is performed at a timing such as when the exhaust gas circulation in the internal combustion engine is started or when the reforming reaction in the reformer is started. Preferably it is done. Here, the timing at which the internal combustion engine is started can be determined by a signal input to the controller 40 from the main fuel supply device 12a, the intake control valve 12b, the intake valve 11c, the piston 11e, and the like. Further, the timing at which exhaust gas circulation in the internal combustion engine is started can be determined by a signal input from the exhaust control valve 13a to the controller 40, for example. Furthermore, the timing at which the reforming reaction in the reformer is started can be determined by, for example, a signal input from the fuel supply device 20 to the controller 40. Since the reforming catalyst and the atmospheric temperature are high at the timing when exhaust gas circulation is started, the reduction regeneration process can be performed in a shorter time. Further, the timing at which the reforming reaction is started in the reformer is, for example, in the internal combustion engine system 1B of this example, the temperature sensor 14d indicated by the broken line is disposed in the reformer 30, and the controller 40, the temperature sensor 14d, Can be determined by a signal input to the controller 40 from the temperature sensor 14d. Since the reforming catalyst and the atmospheric temperature are higher at the timing when the reforming reaction is started, the reduction regeneration process can be performed in a shorter time. Moreover, there exists an advantage that it can transfer to EGR reforming operation which reforms in a reformer as it is.

  Further, in the internal combustion engine system 1B of the present example, for example, an oxygen sensor 14e indicated by a broken line is disposed in the reformer 30, and the controller 40 and the oxygen sensor 14e are connected (not shown), and signals relating to control are transmitted. When the input / output is configured, the reforming catalyst has at least an oxidizing gas having a higher oxygen concentration than the oxidizing gas supplied in the oxidation regeneration process and an oxidizing gas supplied in a larger amount than the oxidizing gas supplied in the oxidation regeneration process. It is also possible to determine the timing of exposure to one by a signal input from the oxygen sensor 14e to the controller 40 and perform an emergency reduction regeneration process for supplying a reducing gas to an oxidizing component generated on the reforming catalyst. For example, even during the EGR reforming operation, when suddenly exposed to a predetermined oxidizing gas, the reducing gas can be urgently supplied to the oxidizing component generated on the reforming catalyst. It is possible to suppress or prevent performance degradation due to oxidation of the reforming catalyst without detecting performance degradation / degradation of the reforming catalyst.

(Example 3)
FIG. 4 is an explanatory diagram showing an outline of the internal combustion engine system of the third embodiment. In addition, about the structure same as Example 1, the overlapping description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  As shown in FIG. 4, the internal combustion engine system 1 </ b> C of this example has a reforming catalyst reduction and regeneration device upstream of the reformer 30 of the EGR pipe 14 in the exhaust gas flow direction (indicated by an arrow α in the figure). 14a is not provided, and a partial oxidation reaction air supply device 14f for supplying partial oxidation reaction air is provided in the EGR pipe 14, and the reforming fuel and the fuel supplied by the fuel supply device 20 are partially provided. When the partial oxidation reaction is caused by using the air supplied by the oxidation reaction air supply device 14f, the reduction regeneration supply is performed intermittently and stepwise to perform the reduction regeneration process. This is different from the internal combustion engine system of the third embodiment. Although not shown, a reforming catalyst reduction regeneration device 14a may be separately provided. In the internal combustion engine system 1C of this example, the partial oxidation reaction air supply device 14f may be subjected to oxidation regeneration treatment, and the exhaust gas flow direction (arrow α in the figure) from the reformer 30 of the EGR pipe 14 may be used. A reforming catalyst oxidation regeneration device (not shown) such as a secondary air supply device may be separately provided on the upstream side.

  In this way, the oxidation regeneration process for supplying the oxidizing gas to the carbon component generated by the reforming reaction is performed on the reforming catalyst, and the reducing gas is supplied to the oxidizing component generated by the oxidation regeneration process on the reforming catalyst. By adopting a regenerative treatment configuration, the hydrogen generation ability of the reforming catalyst can be quickly recovered, and performance degradation due to oxidation of the reforming catalyst can be suppressed or prevented without detecting degradation or deterioration of the performance of the reforming catalyst. be able to. Moreover, since the desired reformed gas can be obtained, the fuel efficiency of the internal combustion engine system can be improved. When supplying reforming fuel that can generate hydrogen instead of hydrogen, if the temperature of the reforming catalyst is too low, carbon deposition may occur, but the partial oxidation reaction proceeds from a lower temperature than the steam reforming reaction. Therefore, it is suitable when the temperature of the reforming catalyst is low. Therefore, in accordance with the operating load of the internal combustion engine and the exhaust gas circulation rate of the internal combustion engine, as shown by the solid line in FIG. It is preferable to supply it intermittently and in stages. Note that air may be supplied as indicated by a broken line in FIG. 2E, and it is needless to say that it is not necessary to supply air separately if the oxygen concentration in the exhaust gas is sufficient for the partial oxidation reaction.

  More specifically, the process in which the deposited carbon is oxidized will be described. The carbon component deposited on the catalyst is oxidized at a temperature higher than the temperature at which the oxidation reaction can proceed and is supplied with oxygen at a certain concentration or higher. Desorbed from the catalyst surface in the state of carbon or oxygen monoxide. At that time, since the catalyst surface is exposed to the oxygen-containing gas at a high temperature, the catalyst surface is oxidized. Note that the oxidation temperature and the required oxygen concentration vary depending on the catalyst specifications.

  Further, the process of reducing the catalyst surface will be described more specifically. The catalyst surface is reduced by supplying a reducing component to the catalyst surface oxidized by the above process at a certain temperature or higher. As the reducing component, hydrogen is desirable, but a hydrocarbon capable of generating hydrogen can be substituted. Similarly to the oxidation, the reducible temperature and the hydrogen concentration necessary for the reduction vary depending on the catalyst specifications.

  Further, in the internal combustion engine system 1C of the present example, for example, at any time such as when the internal combustion engine is started, when exhaust gas circulation in the internal combustion engine is started, or when a reforming reaction is started in the reformer. Although the reduction regeneration process can be performed, it is preferable to perform the reduction regeneration process at a time such as when the internal combustion engine is started from the viewpoint that the exhaust gas temperature is low. Here, the timing at which the internal combustion engine is started can be determined by a signal input to the controller 40 from the main fuel supply device 12a, the intake control valve 12b, the intake valve 11c, the piston 11e, and the like. Further, the timing at which exhaust gas circulation in the internal combustion engine is started can be determined by a signal input from the exhaust control valve 13a to the controller 40, for example. Furthermore, the timing at which the reforming reaction in the reformer is started can be determined by, for example, a signal input from the fuel supply device 20 to the controller 40. Since the reforming catalyst and the atmospheric temperature are high at the timing when exhaust gas circulation is started, the reduction regeneration process can be performed in a shorter time. The timing at which the reforming reaction in the reformer is started is, for example, in the internal combustion engine system 1B of the present example, where the reformer 30 is provided with a diagrammatic temperature sensor 14d indicated by a broken line, and the controller 40 and the temperature sensor 14 Is connected (not shown), and a signal related to control is input / output, it can also be determined by a signal input to the controller 40 from the temperature sensor 14d. Since the reforming catalyst and the atmospheric temperature are higher at the timing when the reforming reaction is started, the reduction regeneration process can be performed in a shorter time. Moreover, there exists an advantage that it can transfer to EGR reforming operation which reforms in a reformer as it is.

  Further, in the internal combustion engine system 1C of this example, for example, an oxygen sensor 14e indicated by a broken line is disposed in the reformer 30, and the controller 40 and the oxygen sensor 14e are connected (not shown), and signals relating to control are transmitted. When the input / output is configured, the reforming catalyst has at least an oxidizing gas having a higher oxygen concentration than the oxidizing gas supplied in the oxidation regeneration process and an oxidizing gas supplied in a larger amount than the oxidizing gas supplied in the oxidation regeneration process. It is also possible to determine the timing of exposure to one by a signal input from the oxygen sensor 14e to the controller 40 and perform an emergency reduction regeneration process for supplying a reducing gas to an oxidizing component generated on the reforming catalyst. For example, even during the EGR reforming operation, when suddenly exposed to a predetermined oxidizing gas, the reducing gas can be urgently supplied to the oxidizing component generated on the reforming catalyst. It is possible to suppress or prevent performance degradation due to oxidation of the reforming catalyst without detecting performance degradation / degradation of the reforming catalyst.

  Furthermore, in the internal combustion engine system 1C of the present example, when the reformer 30 and the atmospheric temperature thereof are lower than the temperature at which the steam reforming reaction proceeds and above the temperature at which the partial oxidation reaction proceeds, the fuel supply device 20 When the partial oxidation reaction is caused to occur by using the reforming fuel supplied by the air and the air supplied by the partial oxidation reaction air supply device 14f, the supply of the reforming fuel is reduced intermittently and stepwise. In addition, when the reduction regeneration process is performed and the temperature is equal to or higher than the temperature at which the steam reforming reaction proceeds, the fuel supply device 20 is configured to reduce the reducing gas set according to the operating load of the internal combustion engine and the exhaust gas circulation rate in the internal combustion engine. It is necessary to separately provide a reforming catalyst reduction and regeneration device (for example, a hydrogen cylinder) by supplying the reforming fuel so as to supply more reducing gas than the supply amount and performing the reduction and regeneration process. Ku, there is the advantage that it is possible to perform the reduction regeneration treatment. Of course, a reforming catalyst reduction / regeneration device may be provided separately, and when the temperature is lower than the temperature at which the partial oxidation reaction proceeds, hydrogen gas may be supplied from the reforming catalyst reduction / regeneration device to perform reduction regeneration processing.

  As mentioned above, although this invention was demonstrated with some embodiment and an Example, this invention is not limited to these, A various deformation | transformation is possible within the range of the summary of this invention.

  That is, the configuration described in the fuel reforming system of each embodiment and each example described above is not limited to each embodiment or example. For example, the configuration of each embodiment or example has been described above. Combinations other than the respective embodiments and examples can be made, and details of the configuration can be changed.

  Further, for example, in each of the above-described embodiments, a reciprocating internal combustion engine is exemplified as the internal combustion engine. However, the present invention is not limited to this and can be applied to a conventionally known internal combustion engine.

1A, 1B, 1C Internal combustion engine system 10 Engine 11 Combustion chamber 11a Intake port 11b Exhaust port 12c Intake valve 13d Exhaust valve 11e Piston 11f Spark plug 12 Intake pipe 12a Main fuel supply device 12b Intake control valve 13 Exhaust pipe 13a Exhaust control valve 14 EGR pipe 14a Reforming catalyst reduction regenerator 14b EGR cooler 14c EGR valve 14d Temperature sensor 14e Oxygen sensor 14f Partial oxidation reaction air supply device (reforming catalyst oxidation regenerator)
20 Fuel Injection Device 30 Reformer 40 Controller

Claims (14)

An internal combustion engine having a combustion chamber, an intake passage and an exhaust passage connected to the combustion chamber, and an exhaust circulation passage connected to the exhaust passage and the intake passage;
A fuel supply device for supplying reforming fuel into the exhaust circulation passage;
A reformer having a reforming catalyst that is disposed in the exhaust circulation channel and generates a reformed gas containing hydrogen by a reforming reaction using the exhaust gas in the exhaust circulation channel and the reforming fuel; With
Reduction for supplying an oxidizing gas to the carbon component generated by the reforming reaction on the reforming catalyst and supplying a reducing gas to the oxidizing component generated by the oxidation regeneration process on the reforming catalyst An internal combustion engine system that performs a regeneration process.   The internal combustion engine system according to claim 1, wherein the reduction regeneration process is performed when the internal combustion engine is started.   The internal combustion engine system according to claim 1 or 2, wherein the reduction regeneration process is performed when exhaust gas circulation in the internal combustion engine is started.   The internal combustion engine system according to any one of claims 1 to 3, wherein the reduction regeneration process is performed when a reforming reaction in the reformer is started.   When the reforming catalyst is exposed to at least one of an oxidizing gas having a higher oxygen concentration than the oxidizing gas supplied in the oxidation regeneration process and an oxidizing gas supplied in a larger amount than the oxidizing gas supplied in the oxidation regeneration process, The internal combustion engine system according to any one of claims 1 to 4, wherein an emergency reduction regeneration process is performed in which a reducing gas is supplied to an oxidizing component generated on the reforming catalyst.   6. The internal combustion engine system according to claim 1, wherein a supply amount of the reducing gas is a fixed value.   6. The internal combustion engine system according to claim 1, wherein a supply amount of the reducing gas is a variable value.   The internal combustion engine system according to claim 7, wherein the supply amount of the reducing gas is a variable value set in accordance with an operation load of the internal combustion engine.   9. The internal combustion engine system according to claim 7, wherein the supply amount of the reducing gas is a variable value set according to an exhaust gas circulation rate in the internal combustion engine.   The internal combustion engine system according to claim 1, further comprising a reforming catalyst reduction and regeneration device that performs the reduction and regeneration process.   The fuel supply device supplies the reforming fuel so as to supply more reducing gas than the amount of reducing gas supplied in accordance with the operating load of the internal combustion engine and the exhaust gas circulation rate in the internal combustion engine; The internal combustion engine system according to any one of claims 1 to 10, wherein the reduction regeneration process is performed. A partial oxidation reaction air supply device for supplying partial oxidation reaction air into the exhaust circulation channel;
When the partial oxidation reaction is caused to occur using the reforming fuel supplied by the fuel supply device and the air supplied by the partial oxidation reaction air supply device, the supply of the reforming fuel is intermittently and stepwise. The internal combustion engine system according to any one of claims 1 to 11, wherein the reduction regeneration process is performed in a reduced manner.   The internal combustion engine system according to claim 12, wherein the partial oxidation reaction air supply device performs the oxidation regeneration process.   The internal combustion engine system according to any one of claims 1 to 13, further comprising a reforming catalyst oxidation regeneration device that performs the oxidation regeneration treatment.

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