JP2010043640A - Reformed gas production device and reformed gas combustion engine system equipped with the same, and activity recovery method of reformed catalyst - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To recover the activity of a reformed catalyst while suppressing the sintering of the reformed catalyst. <P>SOLUTION: The reformed gas generation device 10 is provided with the reformed catalyst 62 for generating reformed gas from ethanol-blended gasoline, an exhaust gas catalyst 60 for heating the reformed catalyst, a pump 20 for reformation and an injector 22 for reformation for supplying the ethanol blended gasoline to the reformed catalyst 62, an upstream side EGR (exhaust gas recirculation) duct 48 for supplying EGR gas to the reformed catalyst 62 and an ECU (electronic control unit) 32. When the reformed catalyst 62 is in a temperature range (500-700°C) lower than a temperature range in which sulfur precipitated in the reformed catalyst 62 in accordance with a reforming reaction can be burnt and removed, the ECU 32 recovers the activity of the reformed catalyst 62 by burning and removing carbon and hydrocarbon precipitated in the reformed catalyst 62 by stopping the supply of the ethanol-blended gasoline to the reformed catalyst 62 and supplying the EGR gas to the reformed catalyst 62. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reformed gas generator, a reformed gas combustion engine system including the reformed gas generator, and a method for recovering the activity of a reformed catalyst.

  Conventionally, the following is known as a method for recovering the activity of a reforming catalyst (see, for example, Patent Document 1). That is, the invention described in Patent Document 1 is a method for controlling catalytic activity in a reforming reaction of an automobile fuel using a catalyst, in which coke and unreacted components deposited on the surface of the catalyst by the reforming reaction are treated with oxygen-enriched components. In this method, burn-off is performed in the presence of chemical air to suppress deterioration of the catalyst.

JP 2005-262040 A Japanese Patent No. 3546658

  However, in the case of burn-off under the condition that air with a high oxygen concentration is supplied to the reforming catalyst and the temperature of the reforming catalyst is in a high temperature range, the activity of the reforming catalyst may be recovered in a relatively short time. In ordinary reforming catalysts, it is considered that the activity gradually decreases due to sintering after long-term use.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a reformed gas generation device and a reformer that can recover the activity of the reforming catalyst while suppressing sintering of the reforming catalyst. The object is to provide a method for recovering the activity of a catalyst.

  Another object of the present invention is to provide a reformed gas combustion engine capable of improving durability and improving fuel efficiency by restoring the activity of the reforming catalyst while suppressing sintering of the reforming catalyst. To provide a system.

  In order to solve the above-mentioned problem, the reformed gas generating apparatus according to claim 1 is a reforming reaction that generates a reformed gas containing hydrogen from a reformed raw material containing sulfur and hydrocarbons by being heated. A reforming catalyst, a heating unit that heats the reforming catalyst using thermal energy of exhaust gas discharged from the engine, and a reforming material supply unit that supplies the reforming material to the reforming catalyst An oxygen-containing gas supply unit that supplies an oxygen-containing gas to the reforming catalyst; and the reforming material supply unit converts the reforming catalyst into the reforming catalyst so that the reformed gas is generated by the reforming catalyst. A reformed gas generation function for supplying a raw material, and the reforming catalyst when the reforming catalyst is in a temperature range lower than a temperature range in which sulfur deposited on the reforming catalyst can be removed by combustion. Before the reforming catalyst by the raw material supply unit The reforming raw material is stopped and the oxygen-containing gas is supplied to the reforming catalyst by the oxygen-containing gas supply unit, so that carbon and hydrocarbons deposited on the reforming catalyst are burned and removed, and the reforming is performed. And a control unit that selectively executes a reforming catalyst activity recovery function that recovers the activity of the catalyst.

  In the reformed gas generation apparatus according to claim 1, when the reformed gas generation function is executed by the control unit, the reformed material is supplied to the reformed catalyst by the reformed material supply unit, and the reformed catalyst is heated. The reformed gas is generated by being heated by the unit.

  Here, when a reforming reaction for generating a reformed gas from a reforming raw material containing sulfur and hydrocarbons is performed in the reforming catalyst, carbon, hydrocarbons, and sulfur are deposited on the reforming catalyst. The deposited carbon, hydrocarbon, and sulfur make it difficult for the reforming reaction to proceed with the reforming catalyst. However, when the deposited carbon, hydrocarbon, and sulfur are removed by combustion, the activity of the reforming catalyst is restored.

  However, it is not necessary for the reforming catalyst to have a high temperature in order to burn and remove (oxidize and remove) carbon and hydrocarbons, but in order to burn and remove sulfur, the reforming catalyst needs to have a high temperature. However, the reforming catalyst is usually in a reducing atmosphere during the reforming reaction, and if the sulfur is burned and removed while the reforming catalyst is at a high temperature, the reforming catalyst is sintered and prolonged due to the high temperature and oxidizing atmosphere. It becomes impossible to withstand the use of time (the reforming catalyst deteriorates).

  On the other hand, as a result of intensive studies, the inventors have found that if the carbon and hydrocarbons are removed by combustion, the activity of the reforming catalyst can be recovered without removing the sulfur by combustion. That is, in order to recover the activity of the reforming catalyst, it is not necessary to burn and remove sulfur, and it is sufficient to burn and remove carbon and hydrocarbons.

  In the reformed gas generation apparatus according to claim 1, the reforming catalyst activity recovery function is executed by the control unit so that the activity of the reforming catalyst is recovered by the sulfur deposited on the reforming catalyst. The temperature range is lower than the temperature range in which combustion can be removed. Accordingly, since the recovery of the activity of the reforming catalyst is performed in a temperature range lower than the high temperature range necessary for burning and removing sulfur, the occurrence of sintering in the reforming catalyst can be suppressed.

  Moreover, although sulfur is not burned and removed, carbon and hydrocarbons can be burned and removed by executing the reforming catalyst activity recovery function by the control unit. Thereby, the activity of the reforming catalyst can be recovered.

  Thus, according to the reformed gas generating apparatus of the first aspect, the activity of the reforming catalyst can be recovered while suppressing sintering of the reforming catalyst.

  The reformed gas generating apparatus according to claim 2 is the reformed gas generating apparatus according to claim 1, wherein the reforming raw material is ethanol-mixed gasoline, and the control unit serves as the reforming catalyst activity recovery function. The recovery of the activity of the reforming catalyst is started when the temperature of the reforming catalyst is 500 to 700 ° C, and the activity of the reforming catalyst is activated when the temperature of the reforming catalyst exceeds 700 ° C. It is configured to perform a function to stop recovery.

  Here, when recovering the activity of the reforming catalyst, if the oxygen-containing gas is supplied to the reforming catalyst when the temperature of the reforming catalyst is below 500 ° C. (for example, at 450 ° C.), the reforming catalyst The recovery operation is not stable, and the activity of the reforming catalyst gradually deteriorates. Further, when the oxygen-containing gas is supplied to the reforming catalyst when the temperature of the reforming catalyst exceeds 700 ° C. (for example, at 750 ° C.), the activity of the reforming catalyst seems to be recovered in a relatively short time. However, the activity of a conventional reforming catalyst gradually decreases due to sintering after a long period of use.

  On the other hand, if an oxygen-containing gas is supplied to the reforming catalyst when the temperature of the reforming catalyst is 500 to 700 ° C., even if carbon and hydrocarbon are deposited on the reforming catalyst, the carbon and hydrocarbon are burned. It can be removed to restore the activity of the reforming catalyst.

  Therefore, according to the reformed gas generating apparatus of the second aspect, the recovery of the activity of the reforming catalyst is started when the temperature of the reforming catalyst is 500 to 700 ° C., and the temperature of the reforming catalyst is 700. Since the recovery of the activity of the reforming catalyst is stopped when the temperature is higher than ° C., the activity of the reforming catalyst can be recovered while suppressing sintering of the reforming catalyst.

  The reformed gas generation apparatus according to claim 3 is the reformed gas generation apparatus according to claim 2, wherein the control unit sets the temperature of the reforming catalyst to 700 ° C as the reforming catalyst activity recovery function. When it exceeds, the oxygen-containing gas supply unit performs a function of stopping the supply of the oxygen-containing gas to the reforming catalyst.

  According to the reformed gas generator of claim 3, since the supply of the oxygen-containing gas to the reforming catalyst is stopped, the recovery of the activity of the reforming catalyst can be stopped.

  The reformed gas generation device according to claim 4 is the reformed gas generation device according to any one of claims 1 to 3, wherein the oxygen-containing gas supply unit is discharged from the engine. A part of the exhaust gas is supplied to the reforming catalyst as the oxygen-containing gas and then introduced into the engine.

  Here, for example, even when the engine is stoichiometrically operated, unburned fuel and oxygen remain in the exhaust gas when passing through the exhaust valve.

  Therefore, as in the reformed gas generating device according to claim 4, if a part of the exhaust gas discharged from the engine is supplied to the reforming catalyst as an oxygen-containing gas and then introduced into the engine, the reforming is achieved. A dedicated device for supplying the oxygen-containing gas to the catalyst can be eliminated. Thereby, an increase in cost can be suppressed.

  The reformed gas generator according to claim 5 is the reformed gas generator according to any one of claims 1 to 4, wherein the engine is an engine for driving a vehicle, and the oxygen-containing gas is used. A supply unit supplies a part of the exhaust gas discharged from the engine as the oxygen-containing gas to the reforming catalyst, and the control unit recovers the reforming catalyst activity when the vehicle is decelerating. Is configured to execute.

  Here, when the vehicle is decelerating (for example, during engine braking), the engine sucks a small amount of air and performs intake / exhaust operations.

  Therefore, as in the reformed gas generator according to claim 5, when the vehicle is decelerating, if a part of the exhaust gas discharged from the engine is supplied as an oxygen-containing gas to the reforming catalyst, the vehicle The exhaust gas discharged during deceleration can be used effectively.

  The reformed gas generation device according to claim 6 is the reformed gas generation device according to any one of claims 1 to 5, wherein the control unit is configured to control the carbon and the carbonization in the reforming catalyst. The reforming catalyst activity recovery function is executed when the hydrogen deposition state reaches a predetermined state.

  According to the reformed gas generating apparatus of the sixth aspect, the controller recovers the activity of the reforming catalyst only when the precipitation state of carbon and hydrocarbons in the reforming catalyst reaches a predetermined state. The function is executed. Therefore, the activity of the reforming catalyst can be recovered at an appropriate timing according to the degree of deterioration of the reforming catalyst.

  The reformed gas generation apparatus according to claim 7 is the reformed gas generation apparatus according to any one of claims 1 to 6, wherein the oxygen-containing gas supply unit is configured such that an oxygen concentration is time-averaged. The oxygen-containing gas of 0.1 to 1.0% by volume is supplied to the reforming catalyst.

  Here, when recovering the activity of the reforming catalyst, if the oxygen concentration of the oxygen-containing gas supplied to the reforming catalyst is less than 0.1% by volume on a time average, combustion removal of carbon and hydrocarbons Is insufficient, and the activity recovery of the reforming catalyst is also insufficient. Further, when the oxygen concentration of the oxygen-containing gas supplied to the reforming catalyst exceeds 1.0% by volume on a time average, the temperature rise of the reforming catalyst accompanying the combustion removal of carbon and hydrocarbons increases, Sintering occurs in the reforming catalyst.

  On the other hand, when the oxygen concentration of the oxygen-containing gas supplied to the reforming catalyst is 0.1 to 1.0% by volume on a time average, the carbon and hydrocarbons are removed by combustion while the carbon and hydrocarbons are removed by combustion Also, the temperature increase of the reforming catalyst is suppressed.

  Therefore, as in the reformed gas generator according to claim 7, if the oxygen-containing gas having an oxygen concentration of 0.1 to 1.0% by volume on a time average is supplied to the reforming catalyst. While the carbon and hydrocarbons are being removed by combustion, the temperature rise of the reforming catalyst accompanying the combustion and removal of carbon and hydrocarbons can also be suppressed. Thereby, the activity of the reforming catalyst can be recovered while suppressing the sintering of the reforming catalyst more effectively.

  Moreover, in order to solve the said subject, the reformed gas combustion engine system of Claim 8 is an engine, the reformed gas production | generation apparatus as described in any one of Claims 1-7, The said, A reformed gas supply unit configured to supply the reformed gas generated by the reformed gas generation device to the engine.

  According to the reformed gas combustion engine system of the eighth aspect, since the reformed catalyst can be maintained in a state in which the activity is recovered by the reformed gas generating device, durability can be improved.

  Further, since the reforming reaction is stably performed by the reforming catalyst, the reformed gas can be efficiently generated from the reforming raw material, the combustion stability of the engine can be improved, and a large amount of EGR gas can be put into the engine. Further, the lower heating value of the fuel can be increased by the reformed gas. Fuel economy can be improved for the above two reasons.

  In order to solve the above-mentioned problem, the method for recovering a reforming catalyst according to claim 9 generates a reformed gas containing hydrogen from a reformed raw material containing sulfur and hydrocarbons by being heated. When the temperature of the reforming catalyst at which the reforming reaction is carried out is in a temperature range lower than the temperature range in which sulfur deposited on the reforming catalyst can be removed by combustion, the reforming catalyst is supplied to the reforming catalyst. The supply of the reforming raw material is stopped and an oxygen-containing gas is supplied to the reforming catalyst, so that the reforming catalyst burns and removes the carbon and hydrocarbons precipitated during the reforming reaction, thereby improving the reforming catalyst. This is a method for recovering the activity of the catalyst.

  The reforming catalyst according to the ninth aspect generates the reformed gas by being supplied with the reforming raw material and being heated by the heating unit.

  Here, when a reforming reaction for generating a reformed gas from a reforming raw material containing sulfur and hydrocarbons is performed in the reforming catalyst, carbon, hydrocarbons, and sulfur are deposited on the reforming catalyst. The deposited carbon, hydrocarbon, and sulfur make it difficult for the reforming reaction to proceed with the reforming catalyst. However, when the deposited carbon, hydrocarbon, and sulfur are removed by combustion, the activity of the reforming catalyst is restored.

  However, it is not necessary for the reforming catalyst to have a high temperature in order to burn and remove (oxidize and remove) carbon and hydrocarbons, but in order to burn and remove sulfur, the reforming catalyst needs to have a high temperature. However, the reforming catalyst is usually in a reducing atmosphere during the reforming reaction, and if the sulfur is burned and removed while the reforming catalyst is at a high temperature, the reforming catalyst is sintered and prolonged due to the high temperature and oxidizing atmosphere. It becomes impossible to withstand the use of time (the reforming catalyst deteriorates).

  On the other hand, as a result of intensive studies, the inventors have found that if the carbon and hydrocarbons are removed by combustion, the activity of the reforming catalyst can be recovered without removing the sulfur by combustion. That is, in order to recover the activity of the reforming catalyst, it is not necessary to burn and remove sulfur, and it is sufficient to burn and remove carbon and hydrocarbons.

  In the method for recovering a reforming catalyst according to claim 9, the activity of the reforming catalyst is recovered when the temperature is lower than a temperature range in which sulfur deposited on the reforming catalyst can be removed by combustion. It is said that. Accordingly, since the recovery of the activity of the reforming catalyst is performed in a temperature range lower than the high temperature range necessary for burning and removing sulfur, the occurrence of sintering in the reforming catalyst can be suppressed.

  In addition, sulfur is not burned off, but carbon and hydrocarbons are burned off, so that the activity of the reforming catalyst can be recovered.

  Thus, according to the reforming catalyst recovery method of the ninth aspect, the activity of the reforming catalyst can be recovered while suppressing sintering of the reforming catalyst.

  The method for recovering a reforming catalyst according to claim 10 is the method for recovering a reforming catalyst according to claim 9, wherein ethanol gas mixture is used as the reforming material, and the temperature of the reforming catalyst is 500 to 700 ° C. The recovery of the activity of the reforming catalyst is started when the temperature of the reforming catalyst is reached, and the recovery of the activity of the reforming catalyst is stopped when the temperature of the reforming catalyst exceeds 700 ° C.

  Here, when recovering the activity of the reforming catalyst, if the oxygen-containing gas is supplied to the reforming catalyst when the temperature of the reforming catalyst is below 500 ° C. (for example, at 450 ° C.), the reforming catalyst The recovery operation is not stable, and the activity of the reforming catalyst gradually deteriorates. Further, when the oxygen-containing gas is supplied to the reforming catalyst when the temperature of the reforming catalyst exceeds 700 ° C. (for example, at 750 ° C.), the activity of the reforming catalyst seems to be recovered in a relatively short time. However, the activity of a conventional reforming catalyst gradually decreases due to sintering after a long period of use.

  On the other hand, if an oxygen-containing gas is supplied to the reforming catalyst when the temperature of the reforming catalyst is 500 to 700 ° C., even if carbon and hydrocarbon are deposited on the reforming catalyst, the carbon and hydrocarbon are burned. It can be removed to restore the activity of the reforming catalyst.

  Therefore, according to the method for recovering a reforming catalyst according to claim 10, when the temperature of the reforming catalyst is 500 to 700 ° C., the recovery of the activity of the reforming catalyst is started, and the temperature of the reforming catalyst is Since the recovery of the activity of the reforming catalyst is stopped when the temperature exceeds 700 ° C., the activity of the reforming catalyst can be recovered while suppressing sintering of the reforming catalyst.

  The method for recovering a reforming catalyst according to claim 11 is the method for recovering a reforming catalyst according to claim 10, wherein the temperature of the reforming catalyst exceeds 700 ° C when the temperature of the reforming catalyst exceeds 700 ° C. In this method, the supply of the oxygen-containing gas is stopped.

  According to the method for recovering the reforming catalyst according to the eleventh aspect, since the supply of the oxygen-containing gas to the reforming catalyst is stopped, the recovery of the activity of the reforming catalyst can be stopped.

  The method for recovering a reforming catalyst according to claim 12 is the method for recovering a reforming catalyst according to any one of claims 9 to 11, wherein the reforming catalyst is discharged from an engine of a vehicle on which the reforming catalyst is mounted. In this method, a part of the exhaust gas is supplied to the reforming catalyst as the oxygen-containing gas and then introduced into the engine.

  Here, for example, even when the engine is stoichiometrically operated, unburned fuel and oxygen remain in the exhaust gas when passing through the exhaust valve.

  Therefore, if a part of the exhaust gas discharged from the engine is supplied as an oxygen-containing gas to the reforming catalyst and then introduced into the engine as in the method for recovering a reforming catalyst according to claim 12, the modification A dedicated apparatus for supplying the oxygen-containing gas to the catalyst can be eliminated. Thereby, an increase in cost can be suppressed.

  The method for recovering a reforming catalyst according to claim 13 is the method for recovering a reforming catalyst according to any one of claims 9 to 12, wherein a vehicle on which the reforming catalyst is mounted is decelerated. When the temperature of the reforming catalyst is in a temperature range lower than the temperature range in which the sulfur can be removed by combustion, a part of the exhaust gas discharged from the engine of the vehicle is converted into the oxygen-containing gas. And supplying the reforming catalyst to recover the activity of the reforming catalyst.

  Here, when the vehicle is decelerating (for example, during engine braking), fuel injection to the engine is stopped, and the engine sucks a small amount of air and performs intake / exhaust operations.

  Therefore, as in the method for recovering a reforming catalyst according to claim 13, when a part of the exhaust gas discharged from the engine is supplied to the reforming catalyst as an oxygen-containing gas when the vehicle is decelerating, The exhaust gas discharged when the vehicle decelerates can be used effectively.

  The method for recovering a reforming catalyst according to claim 14 is the method for recovering a reforming catalyst according to any one of claims 9 to 13, wherein the carbon and the hydrocarbon are precipitated in the reforming catalyst. When the state becomes a predetermined state, and the temperature of the reforming catalyst is in a temperature range lower than the temperature range in which the sulfur can be burned and removed, the reforming catalyst contains the oxygen In this method, gas is supplied to recover the activity of the reforming catalyst.

  According to the method for recovering a reforming catalyst according to claim 14, the activity of the reforming catalyst is turned on only when the precipitation state of carbon and hydrocarbons in the reforming catalyst reaches a predetermined state. . Therefore, the activity of the reforming catalyst can be recovered at an appropriate timing according to the degree of deterioration of the reforming catalyst.

  The method for recovering a reforming catalyst according to claim 15 is the method for recovering a reforming catalyst according to any one of claims 9 to 14, wherein the oxygen concentration is 0.1 to 1. In the method, the oxygen-containing gas of 0% by volume is supplied to the reforming catalyst.

  Here, when recovering the activity of the reforming catalyst, if the oxygen concentration of the oxygen-containing gas supplied to the reforming catalyst is less than 0.1% by volume on a time average, combustion removal of carbon and hydrocarbons Is insufficient, and the activity recovery of the reforming catalyst is also insufficient. Further, when the oxygen concentration of the oxygen-containing gas supplied to the reforming catalyst exceeds 1.0% by volume on a time average, the temperature rise of the reforming catalyst accompanying the combustion removal of carbon and hydrocarbons increases, Sintering occurs in the reforming catalyst.

  On the other hand, when the oxygen concentration of the oxygen-containing gas supplied to the reforming catalyst is 0.1 to 1.0% by volume on a time average, the carbon and hydrocarbons are removed by combustion while the carbon and hydrocarbons are removed by combustion Also, the temperature increase of the reforming catalyst is suppressed.

  Therefore, as in the method for recovering a reforming catalyst according to claim 15, if an oxygen-containing gas having an oxygen concentration of 0.1 to 1.0% by volume on a time average is supplied to the reforming catalyst. While the carbon and hydrocarbons are being removed by combustion, the temperature rise of the reforming catalyst accompanying the combustion and removal of carbon and hydrocarbons can also be suppressed. Thereby, the activity of the reforming catalyst can be recovered while suppressing the sintering of the reforming catalyst more effectively.

  As described in detail above, according to the present invention, the activity of the reforming catalyst can be recovered while suppressing sintering of the reforming catalyst.

It is a figure showing the whole reformed gas combustion engine system composition concerning a first embodiment of the present invention. It is a figure which shows the engine and exhaust system of FIG. It is a figure which shows the reformer of FIG. 1 more concretely. It is a flowchart showing the flow of operation | movement of ECU in 1st embodiment of this invention. It is a flowchart showing the flow of operation | movement of ECU in 2nd embodiment of this invention. It is a figure which shows the whole structure of the reformed gas combustion engine system which concerns on 3rd embodiment of this invention. It is a flowchart showing the flow of operation | movement of ECU in 3rd embodiment of this invention. It is a flowchart showing the flow of operation | movement of ECU in 3rd embodiment of this invention. It is a figure which shows the whole structure of the reformed gas combustion engine system which concerns on 3rd embodiment of this invention. It is a flowchart showing the flow of operation | movement of ECU in 4th embodiment of this invention. It is explanatory drawing which shows deterioration of a reforming catalyst, recovery | restoration, and the change of adsorption | suction to the catalyst of sulfur. It is a figure which shows the result of having experimented about the effect of supplying oxygen at the time of recovery | restoration of a reforming catalyst. It is a figure which shows the result of having investigated the quantity of sulfur and carbon adsorb | sucked by the reforming catalyst. It is a figure which shows the result investigated about the difference when changing the temperature at the time of a reforming reaction, and the temperature at the time of a recovery reaction about a reforming catalyst. It is a figure which shows the result investigated about the difference when changing the temperature at the time of a reforming reaction, and the temperature at the time of a recovery reaction about a reforming catalyst. It is a figure which shows a result when carrying out recovery reaction at 650 degreeC by making oxygen concentration 1.0% about a reforming catalyst. It is a figure which shows a result when carrying out recovery reaction at 650 degreeC by making oxygen concentration 0.5% about a reforming catalyst. It is a figure which shows a result when carrying out recovery reaction at 600 degreeC by making oxygen concentration 0.5% about a reforming catalyst. It is a figure which shows a result when carrying out recovery reaction at 550 degreeC by making oxygen concentration 0.5% about a reforming catalyst. It is a figure which shows a result when carrying out recovery reaction at 500 degreeC by making oxygen concentration 0.5% about a reforming catalyst. It is a figure which shows the experimental examination result at the time of using another thing as a reforming catalyst. It is an image figure of deterioration and recovery of a reforming catalyst. It is a figure which shows the result of having examined the difference in the performance of a reforming catalyst. It is a figure which shows the result of having examined the difference in the performance of a reforming catalyst. It is a figure explaining the definition of the recovery rate of a reforming catalyst.

[First embodiment]
First, a first embodiment of the present invention will be described.

  FIG. 1 shows an overall configuration of a reformed gas combustion engine system 100 according to the first embodiment of the present invention. The reformed gas combustion engine system 100 shown in this figure is suitably mounted on a vehicle such as a passenger car, for example, and has the following configuration.

  That is, the reformed gas combustion engine system 100 includes an engine 12, a fuel tank 14, a fuel pump 16, a fuel injection injector 18, a reforming pump 20, a reforming injector 22, and an EGR mechanism 24. The reformer 26, the reforming catalyst temperature sensor 28, the exhaust oxygen concentration sensor 30, and the ECU 32 as a control unit are provided as main components.

  The engine 12 is for driving a vehicle, and is, for example, a spark ignition engine. The engine 12 includes a cylinder 34, a piston 36, an intake system 38, an exhaust system 40, an intake valve 42, an exhaust valve 44, and a spark plug 46.

  The fuel tank 14 is for storing ethanol-mixed gasoline as a reforming raw material containing sulfur and hydrocarbons, and the fuel pump 16 is a fuel injection injector 18 that uses the ethanol-mixed gasoline stored in the fuel tank 14. It is set as the structure supplied to. The fuel injection injector 18 is configured to inject the ethanol mixed gasoline supplied from the fuel pump 16 into the intake system 38.

  The reforming pump 20 is configured to supply the ethanol mixed gasoline stored in the fuel tank 14 to the reforming injector 22, and the reforming injector 22 is configured to mix the ethanol mixed supplied from the reforming pump 20. The gasoline is injected into an upstream EGR passage 48 of the EGR mechanism 24 described later.

  The EGR mechanism 24 includes an upstream EGR passage 48, a downstream EGR passage 50, a cooler 52, and an EGR valve 54. The upstream EGR passage 48 is provided on the upstream side with respect to the reforming catalyst 62 described later, and communicates the reforming catalyst 62 with the upstream side with respect to the reformer 26 in the exhaust system 40.

  On the other hand, the downstream EGR passage 50 is provided on the downstream side with respect to the reforming catalyst 62, and communicates the reforming catalyst 62 and the EGR valve 54. The cooler 52 is provided in an intermediate portion of the downstream EGR passage 50, and the EGR valve 54 is configured to supply the EGR gas conveyed by the downstream EGR passage 50 to the intake system 38.

  Here, FIG. 2 shows the engine 12 and the exhaust system 40. As shown in this figure, the upstream EGR passage 48 is configured to extract part of the exhaust gas as EGR gas from the upstream side of the collecting portion 58 in the exhaust manifold 56. The reason for this configuration is that if the EGR gas is collected from a position close to the exhaust valve 44, the oxygen concentration in the EGR gas is easily secured.

  The reformer 26 is provided integrally with the exhaust system 40 and includes an exhaust catalyst 60 serving as a heating unit and a reforming catalyst 62. The exhaust catalyst 60 is composed of, for example, a three-way catalyst and has a function of purifying exhaust gas flowing through the exhaust system 40.

  Here, FIG. 3 shows the reformer 26 more specifically. As shown in this figure, the reformer 26 has a configuration in which, for example, reforming catalysts 62 and exhaust catalysts 60 are alternately arranged. In the reformer 26, the exhaust catalyst 60 is configured to heat the reforming catalyst 62 using the thermal energy of the exhaust gas flowing through the exhaust system 40 described above. That is, the reformer 26 is configured as a heat exchange type reformer.

  On the other hand, the reforming catalyst 62 is configured to include, for example, a zirconia-based carrier material (for example, manufactured by First Rare Elemental Chemical Co., Ltd.). The reforming catalyst 62 is heated by the exhaust catalyst 60 when EGR gas, which is part of the exhaust gas, and ethanol mixed gasoline (reformed raw material) are supplied from the upstream EGR passage 48 described above. The reformed gas is generated. That is, when the reforming catalyst 62 is heated by the exhaust catalyst 60, the reforming catalyst 62 performs a reforming reaction for generating a reformed gas by steam reforming ethanol-mixed gasoline with steam in the EGR gas. It has come to be.

  The reforming catalyst temperature sensor 28 shown in FIG. 1 is provided integrally with the above-described reforming catalyst 62 and outputs a signal corresponding to the temperature of the reforming catalyst 62 to the ECU 32. On the other hand, the exhaust oxygen concentration sensor 30 is provided integrally with the exhaust system 40 and is configured to output a signal corresponding to the oxygen concentration in the exhaust gas flowing through the exhaust system 40 to the ECU 32.

  The ECU 32 is configured to control the pump, the reforming injector 22, and the EGR valve 54 in accordance with signals output from the reforming catalyst temperature sensor 28 and the exhaust oxygen concentration sensor 30. Details of the operation of the ECU 32 will be described later.

  In the present embodiment, the reforming pump 20 and the reforming injector 22 correspond to the reforming material supply unit in the present invention. The upstream EGR passage 48 and the EGR valve 54 correspond to the oxygen-containing gas supply unit in the present invention. Further, the downstream EGR passage 50, the cooler 52, and the EGR valve 54 correspond to the reformed gas supply unit in the present invention.

  Further, in the reformed gas combustion engine system 100, the reforming catalyst 62, the exhaust catalyst 60 (heating unit), the reforming pump 20, the reforming injector 22 (reforming raw material supply unit), the upstream EGR passage 48, and The reformed gas generator 10 is configured by the EGR valve 54 (oxygen-containing gas supply unit).

  Next, the operation of the reformed gas combustion engine system 100 according to the first embodiment of the present invention will be described.

  FIG. 4 shows a flowchart showing the flow of operation of the ECU 32. The ECU 32 executes the program shown in the flowchart of FIG.

  That is, when the program shown in the flowchart of FIG. 4 is started, the ECU 32 opens the EGR valve 54 in step S1, and the EGR gas (water vapor-containing gas) that is part of the exhaust gas flowing through the exhaust system 40 is upstream. The side EGR passage 48, the reforming catalyst 62, and the downstream side EGR passage 50 are circulated.

  Subsequently, in step S <b> 2, the ECU 32 operates the reforming pump 20 and the reforming injector 22 to supply ethanol-mixed gasoline as a reforming raw material stored in the fuel tank 14 to the upstream EGR passage 48.

  As a result, the reforming catalyst 62 is heated by the exhaust catalyst 60, and the reforming catalyst 62 performs a reforming reaction in which the ethanol-mixed gasoline is steam reformed with the steam in the EGR gas to generate reformed gas. The reformed gas generated by the reforming catalyst 62 is supplied to the intake system 38 through the downstream EGR passage 50, the cooler 52, and the EGR valve 54. The reformed gas supplied to the intake system 38 is supplied into the cylinder 34 together with the fuel gas of ethanol mixed gasoline injected from the fuel injector 18 and burned in the cylinder 34.

  In step S3, the ECU 32 detects the signal output from the reforming catalyst temperature sensor 28. In step S4, the ECU 32 detects the temperature of the reforming catalyst 62 based on the signal output from the reforming catalyst temperature sensor 28. It is determined whether or not it is within a preset range (600 to 700 ° C.).

  Subsequently, when the ECU 32 determines in step S4 that the temperature of the reforming catalyst 62 is within a preset range (600 to 700 ° C.), the ECU 32 outputs the temperature from the exhaust oxygen concentration sensor 30 in step S5. A signal is detected, and in step S6, a range in which the oxygen concentration in the exhaust gas is preset based on the signal output from the exhaust oxygen concentration sensor 30 (0.1 to 1.0% by volume on a time average). It is judged whether it is in.

  Here, when the ECU 32 determines in step S4 that the temperature of the reforming catalyst 62 is not within the preset range (600 to 700 ° C.), or in step S6, the oxygen concentration in the exhaust gas is preset. If it is determined that it is not within the range (0.1 to 1.0% by volume on a time average), the process returns to step S2, and the supply of the ethanol-mixed gasoline to the upstream EGR passage 48 is continued. Thereby, the generation of the reformed gas in the reforming catalyst 62 is continued.

  On the other hand, when the ECU 32 determines in step S6 that the oxygen concentration in the exhaust gas is within a preset range (time average 0.1 to 1.0% by volume), in step S7, EGR. While the valve 54 is opened, the reforming pump 20 and the reforming injector 22 are stopped.

  As a result, the supply of the ethanol mixed gasoline to the reforming catalyst 62 is stopped, and EGR gas (oxygen-containing gas) is supplied from the upstream EGR passage 48 to the reforming catalyst 62, whereby the reforming catalyst 62 is supplied. The deposited carbon and hydrocarbons are burned and removed, and the activity recovery of the reforming catalyst 62 is started.

  Then, when a preset time has elapsed since the start of the recovery of the activity of the reforming catalyst 62, the ECU 32 returns to step S2 and resumes the supply of ethanol-mixed gasoline to the upstream EGR passage 48. Thereby, the activity recovery of the reforming catalyst 62 is stopped, and the generation of the reformed gas in the reforming catalyst 62 is resumed.

  When the ECU 32 determines that the oxygen concentration in the EGR gas discharged from the reforming catalyst 62 has become higher than a preset oxygen concentration after the start of the activity recovery of the reforming catalyst 62, the ECU 32 proceeds to step S2. You can go back. Further, the ECU 32 may return to step S2 when it is determined that the temperature of the reforming catalyst 62 has once increased and then decreased after the start of recovery of the activity of the reforming catalyst 62.

  Then, the ECU 32 repeatedly executes the program shown in the flowchart of FIG. 4 until the engine 12 is stopped.

  In the present embodiment, step S2 executed by the ECU 32 corresponds to the reformed gas generation function in the present invention, and steps S3 to S7 executed by the ECU 32 correspond to the reformed catalyst activity recovery function in the present invention.

  Next, the operation and effect of the first embodiment of the present invention will be described.

  In the reformed gas generation apparatus 10 according to the first embodiment of the present invention, as described above, when step S2 (reformed gas generation function) is executed by the ECU 32, the reforming pump 20 and the reforming injector 22 are performed. The reforming catalyst 62 is supplied with ethanol-mixed gasoline as a reforming raw material, and the reforming catalyst 62 is heated by the exhaust catalyst 60 to generate reformed gas.

  Here, when a reforming reaction is performed in the reforming catalyst 62 to generate reformed gas from ethanol mixed gasoline containing sulfur and hydrocarbons, carbon, hydrocarbons, and sulfur are deposited on the reforming catalyst 62. The deposited carbon, hydrocarbon, and sulfur make it difficult for the reforming reaction to proceed in the reforming catalyst 62. However, when the deposited carbon, hydrocarbon, and sulfur are removed by combustion, the activity of the reforming catalyst 62 is restored. .

  However, the reforming catalyst 62 does not need to be at a high temperature to remove carbon (hydrocarbon) by oxidation (oxidation), but the reforming catalyst 62 has a high temperature (for example, 750 ° C. or more) to remove sulfur by combustion. There must be. However, the reforming catalyst 62 is normally in a reducing atmosphere during the reforming reaction. When sulfur is burned and removed while the reforming catalyst 62 is at a high temperature, the reforming catalyst 62 is sintered due to the high temperature and oxidizing atmosphere. Thus, it cannot withstand long-term use (the reforming catalyst 62 deteriorates).

  On the other hand, as a result of intensive studies, the inventors have found that if carbon and hydrocarbons are removed by combustion, the activity of the reforming catalyst 62 can be recovered without removing sulfur by combustion. That is, in order to restore the activity of the reforming catalyst 62, it is not necessary to burn and remove sulfur, and it is sufficient to burn and remove carbon and hydrocarbons.

  And in the reformed gas production | generation apparatus 10 which concerns on 1st embodiment of this invention, as mentioned above, ECU32 performs step S3-step S7 (reformation catalyst activity recovery function) of the reforming catalyst 62. The activity is restored when the temperature of the reforming catalyst 62 is 600 to 700 ° C., which is lower than the temperature range in which sulfur deposited on the reforming catalyst 62 can be removed by combustion (for example, 750 ° C. or more). It is said that it is in the temperature range. Accordingly, since the recovery of the activity of the reforming catalyst 62 is performed in a temperature range lower than the high temperature range necessary for burning and removing sulfur, the occurrence of sintering in the reforming catalyst 62 can be suppressed.

  In addition, although sulfur is not burned and removed, the ECU 32 can execute steps S3 to S7 (reforming catalyst activity recovery function) to burn and remove carbon and hydrocarbons. Thereby, the activity of the reforming catalyst 62 can be recovered.

  Thus, according to the reformed gas generation device 10 according to the first embodiment of the present invention, the activity of the reforming catalyst 62 can be recovered while suppressing sintering of the reforming catalyst 62.

  In the reformed gas generation apparatus 10 according to the first embodiment of the present invention, EGR gas whose oxygen concentration is 0.1 to 1.0% by volume on a time average is supplied to the reforming catalyst 62.

  Here, when recovering the activity of the reforming catalyst 62, if the oxygen concentration of the oxygen-containing gas supplied to the reforming catalyst 62 is below 0.1% by volume on a time average, carbon and hydrocarbons Combustion removal is insufficient, and the activity recovery of the reforming catalyst 62 is also insufficient. Further, if the oxygen concentration of the oxygen-containing gas supplied to the reforming catalyst 62 exceeds 1.0 vol% on a time average, the temperature rise of the reforming catalyst 62 accompanying the combustion removal of carbon and hydrocarbons is large. Thus, sintering occurs in the reforming catalyst 62.

  On the other hand, when the oxygen concentration of the oxygen-containing gas supplied to the reforming catalyst 62 is 0.1 to 1.0% by volume on a time average, the combustion of carbon and hydrocarbons is performed while burning and removing carbon and hydrocarbons. The temperature rise of the reforming catalyst 62 accompanying the removal is also suppressed.

  Therefore, as described above, if EGR gas whose oxygen concentration is 0.1 to 1.0% by volume on a time average is supplied to the reforming catalyst 62, carbon and hydrocarbons are burned and removed. Moreover, the temperature rise of the reforming catalyst 62 accompanying the combustion removal of carbon and hydrocarbons can also be suppressed. Thereby, the activity of the reforming catalyst 62 can be recovered while suppressing the sintering of the reforming catalyst 62 even more effectively.

  For example, even when the engine 12 is stoichiometrically operated, unburned fuel and oxygen remain in the exhaust gas when passing through the exhaust valve 44.

  Therefore, like the reformed gas generator 10 according to the first embodiment of the present invention, the engine is supplied after supplying EGR gas, which is part of the exhaust gas discharged from the engine 12, to the reforming catalyst 62 as an oxygen-containing gas. 12, a dedicated device for supplying oxygen-containing gas to the reforming catalyst 62 can be eliminated. Thereby, an increase in cost can be suppressed.

  Further, according to the reformed gas combustion engine system 100 provided with the reformed gas generator 10, the reformed catalyst 62 can be maintained in a state in which the activity has been recovered by the reformed gas generator 10. Durability can be improved.

  Further, since the reforming reaction is stably performed by the reforming catalyst 62, the reformed gas can be efficiently generated from the ethanol mixed gasoline which is the reforming raw material, the combustion stability of the engine 12 is improved, and the EGR gas is converted into the engine 12 Can be put in a lot. Further, the lower heating value of the fuel can be increased by the reformed gas. Fuel economy can be improved for the above two reasons.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.

  In the second embodiment of the present invention, the ECU 32 in the reformed gas combustion engine system 100 according to the first embodiment of the present invention described above is caused to execute the program shown in the flowchart of FIG.

  That is, the ECU 32 is configured to execute steps S11 to S14 in addition to steps S1 to S7.

  That is, the ECU 32 detects a signal output from the reforming catalyst temperature sensor 28 in step S11 after step S7, and reforms based on the signal output from the reforming catalyst temperature sensor 28 in step S12. It is determined whether or not the temperature of the catalyst 62 exceeds 700 ° C.

  Here, while the ECU 32 determines in step S12 that the temperature of the reforming catalyst 62 does not exceed 700 ° C., in step S13, a predetermined time has elapsed after the start of recovery of the activity of the reforming catalyst 62. Steps S11 to S13 are repeatedly executed until it is determined. Thereby, the activity recovery of the reforming catalyst 62 is continuously performed.

  On the other hand, if the ECU 32 determines in step S12 that the temperature of the reforming catalyst 62 is higher than 700 ° C., the ECU 32 closes the EGR valve 54 in step S14. As a result, the supply of EGR gas (oxygen-containing gas) from the upstream EGR passage 48 to the reforming catalyst 62 is stopped, and the activity recovery of the reforming catalyst 62 is stopped. Then, the ECU 32 returns to step S2.

  Thereby, when the temperature of the reforming catalyst 62 is 600 to 700 ° C., the activity recovery of the reforming catalyst 62 is started again, and the temperature of the reforming catalyst 62 is not 600 to 700 ° C. In this case, the reformed catalyst 62 generates reformed gas. Further, after the recovery of the activity of the reforming catalyst 62 is started and when the temperature of the reforming catalyst 62 exceeds 700 ° C., the recovery of the activity of the reforming catalyst 62 is stopped.

  Then, the ECU 32 repeatedly executes the program shown in the flowchart of FIG. 5 until the engine 12 is stopped.

  Next, the operation and effect of the second embodiment of the present invention will be described.

  In the second embodiment of the present invention, as described above, the activity recovery of the reforming catalyst 62 is started when the temperature of the reforming catalyst 62 is 600 to 700 ° C., and the temperature of the reforming catalyst 62 is 700 ° C. When the temperature exceeds ℃, the recovery of the activity of the reforming catalyst 62 is stopped.

  Here, when the activity of the reforming catalyst 62 is recovered, when the oxygen-containing gas is supplied to the reforming catalyst 62 when the temperature of the reforming catalyst 62 is lower than 600 ° C. (for example, at 550 ° C.), The recovery operation of the reforming catalyst 62 is not stable, and the activity of the reforming catalyst 62 gradually deteriorates. Further, when the oxygen-containing gas is supplied to the reforming catalyst 62 when the temperature of the reforming catalyst 62 exceeds 700 ° C. (for example, at 750 ° C.), the activity of the reforming catalyst 62 is increased in a relatively short time. Even if it seems to have recovered, the activity of the ordinary reforming catalyst 62 gradually decreases due to sintering after a long period of use.

  On the other hand, if an oxygen-containing gas is supplied to the reforming catalyst 62 when the temperature of the reforming catalyst 62 is 600 to 700 ° C., even if carbon and hydrocarbons are deposited on the reforming catalyst 62, The activity of the reforming catalyst 62 can be recovered by burning off hydrogen.

  Therefore, as in the second embodiment of the present invention, when the temperature of the reforming catalyst 62 is 600 to 700 ° C., the activity recovery of the reforming catalyst 62 is started, and the temperature of the reforming catalyst 62 is 700 ° C. If the recovery of the activity of the reforming catalyst 62 is stopped when it exceeds the upper limit, the activity of the reforming catalyst 62 can be recovered while suppressing the sintering of the reforming catalyst 62.

  In the present embodiment, when the temperature of the reforming catalyst 62 exceeds 700 ° C., the supply of the EGR gas to the reforming catalyst 62 is maintained and the reforming pump 20 and the reforming injector 22 are maintained. Is activated and the generation of the reformed gas in the reforming catalyst 62 is started, so that the activity recovery of the reforming catalyst 62 may be stopped.

[Third embodiment]
Next, a third embodiment of the present invention will be described.

  FIG. 6 shows an overall configuration of a reformed gas combustion engine system 200 according to the third embodiment of the present invention. In the reformed gas combustion engine system 200 according to the third embodiment of the present invention, a CPU 72 is connected to the ECU 32 with respect to the above-described reformed gas combustion engine system 100 according to the first embodiment of the present invention. Has been modified to work as follows:

  The CPU 72 is for vehicle integrated control, and is configured to output to the ECU 32 a signal corresponding to a signal output from a switch that detects an on / off operation state of an accelerator pedal (not shown).

  Next, the operation of the reformed gas combustion engine system 200 according to the third embodiment of the present invention will be described.

  7 and 8 are flowcharts showing the flow of the operation of the ECU 32. The ECU 32 executes the program shown in the flowchart of FIG. 7 while it is determined that the accelerator pedal is turned off based on the signal output from the CPU 72 (that is, while the vehicle is decelerating). Note that, before the ECU 32 executes the program shown in the flowchart of FIG. 7, the EGR valve 54 is closed, and the reforming pump 20 and the reforming injector 22 are stopped.

  When the program shown in the flowchart of FIG. 7 is started, the ECU 32 detects the signal output from the reforming catalyst temperature sensor 28 in step S21, and the signal output from the reforming catalyst temperature sensor 28 in step S22. Based on the above, it is determined whether or not the temperature of the reforming catalyst 62 is in a preset range (600 to 700 ° C.).

  If the ECU 32 determines in step S22 that the temperature of the reforming catalyst 62 is not within a preset range (600 to 700 ° C.), the ECU 32 proceeds to step S26 described later (that is, no action is taken). Without keeping the EGR valve 54 closed).

  On the other hand, if the ECU 32 determines in step S22 that the temperature of the reforming catalyst 62 is within a preset range (600 to 700 ° C.), the ECU 32 opens the EGR valve 54 in step S23.

  As a result, the EGR gas (oxygen-containing gas) is supplied from the upstream EGR passage 48 to the reforming catalyst 62, whereby carbon and hydrocarbons deposited on the reforming catalyst 62 are burned and removed, and the activity of the reforming catalyst 62 is increased. Recovery begins.

  Subsequently, the ECU 32 detects a signal output from the reforming catalyst temperature sensor 28 in step S24, and in step S25, based on the signal output from the reforming catalyst temperature sensor 28, the temperature of the reforming catalyst 62 is detected. It is determined whether or not the temperature exceeds 700 ° C.

  Here, the ECU 32 repeatedly executes steps S21 to S25 while determining that the temperature of the reforming catalyst 62 does not exceed 700 ° C. in step S25. Thereby, the activity recovery of the reforming catalyst 62 is continuously performed.

  On the other hand, if the ECU 32 determines in step S25 that the temperature of the reforming catalyst 62 is higher than 700 ° C., the ECU 32 closes the EGR valve 54 in step S26. As a result, the supply of EGR gas (oxygen-containing gas) from the upstream EGR passage 48 to the reforming catalyst 62 is stopped, and the activity recovery of the reforming catalyst 62 is stopped. Then, the ECU 32 returns to step S21.

  Thereby, when the temperature of the reforming catalyst 62 is 600 to 700 ° C., the activity recovery of the reforming catalyst 62 is started again, and the temperature of the reforming catalyst 62 is not 600 to 700 ° C. In this case, the recovery of the activity of the reforming catalyst 62 is not started. Further, after the recovery of the activity of the reforming catalyst 62 is started and when the temperature of the reforming catalyst 62 exceeds 700 ° C., the recovery of the activity of the reforming catalyst 62 is stopped.

  Then, the ECU 32 repeatedly executes the program shown in the flowchart of FIG. 7 until the accelerator pedal is turned on.

  In the present embodiment, steps S21 to S26 executed by the ECU 32 correspond to the reforming catalyst activity recovery function in the present invention.

  On the other hand, the ECU 32 executes the program shown in the flowchart of FIG. 8 while determining that the accelerator pedal is on based on the signal output from the CPU 72 (that is, while the vehicle is accelerating). To do.

  That is, when the program shown in the flowchart of FIG. 8 is started, the ECU 32 determines whether to open the EGR valve 54 or to close the EGR valve 54 in step S31 by comparing with a request map preset in the CPU 72. To do. At this time, the ECU 32 may determine whether to open the EGR valve 54 or close the EGR valve 54 based on, for example, an acceleration signal output from the CPU 72 according to the acceleration state of the vehicle.

  If the ECU 32 determines in step S31 that the EGR valve 54 is to be opened, the ECU 32 opens the EGR valve 54 and activates the reforming pump 20 and the reforming injector 22 in step S32. The ethanol mixed gasoline stored in the tank 14 is supplied to the upstream EGR passage 48.

  As a result, the reforming catalyst 62 is heated by the exhaust catalyst 60, and the reforming catalyst 62 performs a reforming reaction in which the ethanol-mixed gasoline is steam reformed with the steam in the EGR gas to generate reformed gas. The reformed gas generated by the reforming catalyst 62 is supplied to the intake system 38 through the downstream EGR passage 50, the cooler 52, and the EGR valve 54. The reformed gas supplied to the intake system 38 is supplied into the cylinder 34 together with the fuel gas of ethanol mixed gasoline injected from the fuel injector 18 and burned in the cylinder 34.

  On the other hand, if the ECU 32 determines in step S31 that the EGR valve 54 is to be closed, the ECU 32 closes the EGR valve 54 in step S33. Thereby, when the recovery of the activity of the reforming catalyst 62 has been executed before the ECU 32 executes the program shown in the flowchart of FIG. 8, the EGR gas from the upstream EGR passage 48 to the reforming catalyst 62 is recovered. The supply of (oxygen-containing gas) is stopped, and the activity recovery of the reforming catalyst 62 is stopped.

  Then, the ECU 32 repeatedly executes the program shown in the flowchart of FIG. 8 until the accelerator pedal is turned off.

  In the present embodiment, step S32 executed by the ECU 32 corresponds to the reformed gas generation function in the present invention.

  Next, the operation and effect of the third embodiment of the present invention will be described.

  In the third embodiment of the present invention, the ECU 32 executes steps S21 to S26 (reforming catalyst activity recovery function) when the vehicle on which the engine 12 is mounted is decelerating.

  Here, when an accelerator pedal (not shown) is turned off and the vehicle is decelerating (for example, when the engine 12 is braked), the engine 12 sucks a small amount of air and performs an intake / exhaust operation.

  Accordingly, when the vehicle is decelerating as in this embodiment, if EGR gas, which is part of the exhaust gas discharged from the engine 12, is supplied as an oxygen-containing gas to the reforming catalyst 62, the vehicle is decelerated. The exhaust gas discharged can be used effectively.

[Fourth embodiment]
Next, a fourth embodiment of the present invention will be described.

  FIG. 9 shows an overall configuration of a reformed gas combustion engine system 300 according to the fourth embodiment of the present invention. The reformed gas combustion engine system 300 according to the fourth embodiment of the present invention has an exhaust gas temperature sensor 74 added to the above-described reformed gas combustion engine system 100 according to the first embodiment of the present invention. The ECU 32 is modified so as to operate as follows.

  The exhaust temperature sensor 74 is provided integrally with the exhaust system 40 and outputs a signal corresponding to the temperature of the exhaust gas flowing through the exhaust system 40 to the ECU 32.

  Next, the operation of the reformed gas combustion engine system 300 according to the fourth embodiment of the present invention will be described.

  FIG. 10 shows a flowchart showing the flow of operation of the ECU 32. In this embodiment, ECU32 is comprised so that step S41-step S45 may be performed between the above-mentioned step S6 and step S7.

  That is, after step S6, the ECU 32 detects the signal output from the exhaust temperature sensor 74 in step S41 and also detects the signal output from the reforming catalyst temperature sensor 28. In step S42, the ECU 32 detects the exhaust gas. The difference between the temperature and the temperature of the reforming catalyst 62 is calculated.

  Subsequently, in step 43, the ECU 32 compares the previously stored map of calculated values of the degree of deterioration and the temperature difference of the reforming catalyst 62 with the calculated value of the temperature difference, and in step 44, the reforming catalyst. 62 is determined (that is, the deposition state of carbon and hydrocarbons in the reforming catalyst 62).

  The steam reforming reaction of ethanol-mixed gasoline is an endothermic reaction, and when an endothermic reaction occurs in the reforming catalyst 62, the temperature of the reforming catalyst 62 is the temperature of the exhaust catalyst 60 that is heating the reforming catalyst 62. Less than. Therefore, in the present embodiment, the degree of deterioration of the reforming catalyst 62 is utilized by utilizing the fact that the difference between the temperature of the reforming catalyst 62 and the temperature of the exhaust catalyst 60 (exhaust gas temperature) decreases when the reforming catalyst 62 deteriorates. To detect. In other words, for example, the smaller the difference between the temperature of the exhaust gas and the temperature of the reforming catalyst 62, the more the reforming catalyst 62 is degraded.

  In step 45, the ECU 32 determines whether or not the degree of deterioration of the reforming catalyst 62 has reached a predetermined upper limit value, that is, a predetermined deposition state of carbon and hydrocarbons in the reforming catalyst 62. By determining whether or not it is in a state, it is determined whether or not the activity recovery of the reforming catalyst 62 is necessary.

  Here, when the ECU 32 determines in step 45 that the degree of deterioration of the reforming catalyst 62 has not reached the predetermined upper limit value, that is, when it is determined that the recovery of the activity of the reforming catalyst 62 is not necessary. Returns to step S2 and continues to supply the ethanol-mixed gasoline to the upstream EGR passage 48. Thereby, the generation of the reformed gas in the reforming catalyst 62 is continued.

  On the other hand, when the ECU 32 determines in step 45 that the degree of deterioration of the reforming catalyst 62 has reached a predetermined upper limit value, that is, when it is determined that the activity recovery of the reforming catalyst 62 is necessary. In step S7, the reforming pump 20 and the reforming injector 22 are stopped while the EGR valve 54 is kept open.

  As a result, the supply of the ethanol mixed gasoline to the reforming catalyst 62 is stopped, and EGR gas (oxygen-containing gas) is supplied from the upstream EGR passage 48 to the reforming catalyst 62, whereby the reforming catalyst 62 is supplied. The deposited carbon and hydrocarbons are burned and removed, and the activity recovery of the reforming catalyst 62 is started.

  Then, when a preset time has elapsed since the start of the recovery of the activity of the reforming catalyst 62, the ECU 32 returns to step S2 and resumes the supply of ethanol-mixed gasoline to the upstream EGR passage 48. Thereby, the activity recovery of the reforming catalyst 62 is stopped, and the generation of the reformed gas in the reforming catalyst 62 is resumed.

  When the ECU 32 determines that the oxygen concentration in the EGR gas discharged from the reforming catalyst 62 has become higher than a preset oxygen concentration after the start of the activity recovery of the reforming catalyst 62, the ECU 32 proceeds to step S2. You can go back. Further, the ECU 32 may return to step S2 when it is determined that the temperature of the reforming catalyst 62 has once increased and then decreased after the start of recovery of the activity of the reforming catalyst 62.

  Then, the ECU 32 repeatedly executes the program shown in the flowchart of FIG. 10 until the engine 12 is stopped.

  In the present embodiment, step S2 executed by the ECU 32 corresponds to the reformed gas generation function in the present invention, and step S7 executed by the ECU 32 corresponds to the reformed catalyst activity recovery function in the present invention.

  Next, operations and effects of the fourth embodiment of the present invention will be described.

  In the fourth embodiment of the present invention, when it is determined from the difference between the temperature of the exhaust gas and the temperature of the reforming catalyst 62 that the degree of deterioration of the reforming catalyst 62 has reached a predetermined upper limit value, that is, When it is determined that the carbon and hydrocarbon deposition state in the reforming catalyst 62 is in a predetermined state, step S7 (reforming catalyst activity recovery function) is executed by the ECU 32.

  According to this configuration, in the ECU 32, when the degree of deterioration of the reforming catalyst 62 reaches a predetermined upper limit value, that is, the deposition state of carbon and hydrocarbons in the reforming catalyst 62 is set to a predetermined state. Only when this occurs, step S7 (reforming catalyst activity recovery function) is executed. Therefore, the activity of the reforming catalyst 62 can be recovered at an appropriate timing according to the degree of deterioration of the reforming catalyst 62.

  In the present embodiment, step S3 to step S6 and step S41 to step S45 may be interchanged. In this case, step S3 to step S7 executed by the ECU 32 after step S41 to step S45 correspond to the reforming catalyst activity recovery function in the present invention.

  In the present embodiment, the supply of EGR gas to the reforming catalyst 62 is stopped when the temperature of the reforming catalyst 62 exceeds 700 ° C., so that the recovery of the activity of the reforming catalyst 62 is stopped. May be.

  Moreover, step S41-step S45 may be performed between step S22 and step S23 in the above-mentioned third embodiment of the present invention. In this case, if it is determined in step 45 that the degree of deterioration of the reforming catalyst 62 has not reached the predetermined upper limit value, that is, if it is determined that the activity recovery of the reforming catalyst 62 is not necessary. Return to step S21.

  Next, the experimental examination result regarding the reformed gas generation apparatus according to the first embodiment of the present invention will be described.

  FIG. 11 is an explanatory diagram showing deterioration and recovery of the reforming catalyst and changes in adsorption of sulfur to the catalyst. As shown in this figure, as the deterioration of the reforming catalyst proceeds, the concentration of hydrogen in the reformed gas produced by the reforming catalyst decreases, but when the reforming catalyst deteriorates to a predetermined degree of deterioration, the reforming catalyst reforms. By restoring the quality catalyst, the concentration of hydrogen in the reformed gas produced by the reforming catalyst increases.

  Further, since the activity of the reforming catalyst is restored when it is in a temperature range lower than the temperature range in which sulfur can be removed by combustion, the sulfur content in the reforming catalyst becomes constant in a saturated state. However, this figure shows that the reforming catalyst can be recovered by burning off carbon and hydrocarbons.

  FIG. 12 is a diagram showing the results of experiments on the effectiveness of supplying oxygen when the reforming catalyst is recovered. The fuel is a mixture of ethanol and gasoline (ethanol 85% by volume, gasoline 15% by volume), and the reforming catalyst is a cordierite honeycomb coated with 240g / L of zirconia-based carrier and Rh (rhodium) at 2g / L. What was done was used. Further, the reforming catalyst was put in an electric furnace set at 650 ° C., and the reforming reaction (20 minutes) and the recovery reaction (15 minutes) were alternately performed. Each data is measured three times in 20 minutes for each reforming reaction for a reforming catalyst supplied with oxygen (oxygen concentration of 1% by volume in oxygen-containing gas) at the time of recovery and a reforming catalyst not supplied with oxygen at the time of recovery ( This is a result of measuring the concentration of hydrogen in the reformed gas produced by each reforming catalyst when one measurement takes 1 minute and 30 seconds). From this figure, it was found that the hydrogen concentration in the reformed gas was higher when oxygen was supplied during recovery than when oxygen was not supplied during recovery, and the reforming catalyst was recovered.

  However, when recovering the activity of the reforming catalyst, if the oxygen concentration of the oxygen-containing gas supplied to the reforming catalyst is less than 0.1% by volume on a time average, the combustion and removal of carbon and hydrocarbons are prevented. It becomes insufficient, and the activity recovery of the reforming catalyst is also insufficient. Further, when the oxygen concentration of the oxygen-containing gas supplied to the reforming catalyst exceeds 1.0% by volume on a time average, the temperature rise of the reforming catalyst accompanying the combustion removal of carbon and hydrocarbons increases, Sintering occurs in the reforming catalyst. Therefore, the oxygen concentration of the oxygen-containing gas supplied to the reforming catalyst should be 0.1 to 1.0% by volume on a time average.

  FIG. 13 is a graph showing the results of examining the amounts of sulfur and carbon adsorbed on the reforming catalyst after the reforming catalyst recovers when oxygen is supplied during recovery of the reforming catalyst and when oxygen is not supplied. It is. As shown in this figure, the activity of the reforming catalyst is restored when it is in a temperature range lower than the temperature range in which sulfur can be burned and removed. Therefore, regardless of whether oxygen is supplied or not, Sulfur is constant in saturation. On the other hand, it was found from this figure that carbon is burned and removed more when oxygen is supplied when the reforming catalyst is recovered than when oxygen is not supplied.

  FIG. 14 and FIG. 15 are diagrams showing the results of examining the difference when the temperature during the reforming reaction and the temperature during the recovery reaction are changed for the reforming catalyst. As the reforming catalyst, a reforming reaction was performed at 750 ° C. and a recovery reaction was performed at 750 ° C., and a reforming reaction was performed at 600 ° C. and a recovery reaction was performed at 650 ° C. (two types). . Note that oxygen is not supplied during recovery. As shown in FIG. 14, the reforming catalyst in which the reforming reaction was performed at 750 ° C. and the recovery reaction was performed at 750 ° C. first deteriorated after the fuel was added, but the major deterioration was not observed. In addition, the reforming catalyst that had undergone the reforming reaction at 600 ° C. and the recovery reaction at 650 ° C. gradually deteriorated after the fuel was added. Further, as shown in FIG. 15, when the reforming reaction was performed at 750 ° C. and the recovery reaction was performed at 750 ° C., the reforming catalyst became high temperature, so that a large amount of sulfur was reduced. However, when the recovery reaction was performed at 750 ° C., the reforming catalyst was not deteriorated in a short time, but the reforming catalyst was sintered when used for a long time. Therefore, the temperature at the time of recovery of the reforming catalyst should be 700 ° C. or lower.

  FIG. 16 is a diagram showing the results when the reforming catalyst is subjected to a recovery reaction at 650 ° C. with an oxygen concentration in the oxygen-containing gas of 1.0%. As shown in this figure, it is found that when the oxygen concentration in the oxygen-containing gas is 1.0% and the recovery reaction is performed at 650 ° C., the reforming catalyst can be recovered stably. It was.

  17-20 is a figure which shows a result when carrying out recovery reaction at 500-650 degreeC by making oxygen concentration in oxygen-containing gas 0.5% about a reforming catalyst. All reforming reactions were performed at 600 ° C. As shown in FIG. 17, it was found that when the reforming catalyst was allowed to recover at 650 ° C., the reforming catalyst could be recovered stably. Further, as shown in FIG. 18, it was found that when the reforming catalyst was subjected to a recovery reaction at 600 ° C., the reforming catalyst was not rapidly deteriorated and the reforming catalyst could be stably recovered. . On the other hand, as shown in FIG. 19, it was found that when the reforming catalyst was subjected to a recovery reaction at 550 ° C., the recovery of the reforming catalyst was not stable and the reforming catalyst gradually deteriorated. Further, as shown in FIG. 20, it was found that when the reforming catalyst was subjected to a recovery reaction at 500 ° C., the reforming catalyst gradually deteriorated. Therefore, in this case, the temperature at the time of recovery of the reforming catalyst should be 600 ° C. or higher.

  In the above embodiment, a cordierite honeycomb with 240 g / L coat of zirconia-based carrier and 2 g / L of Rh (rhodium) is used as the reforming catalyst. The experimental results in the case of using cerium oxide as the main component (80 wt%), containing 11 wt% aluminum oxide, 9 wt% zirconium oxide, and carrying 2 wt% Rh (rhodium) as a noble metal are shown. .

  FIG. 21 shows a reforming catalyst in which cerium oxide is a main component (80 wt%), contains 11 wt% aluminum oxide, 9 wt% zirconium oxide, and carries 2 wt% Rh (rhodium) as a noble metal. It is a figure which shows the experimental result at the time of using. The experimental conditions in this case are the same as in FIG. The horizontal axis represents the total time that fuel is supplied to the reforming catalyst during reforming of the reforming catalyst. The reforming catalyst was recovered at 500 ° C. with an oxygen concentration of 1% in the oxygen-containing gas.

Further, as a new finding, sulfur in gasoline does not become hydrogen sulfide (H ₂ S) at the time of reforming, but sulfur oxide (SO ₂ ) together with carbon and intermediately generated carbides during the recovery operation of the reforming catalyst. ) And was found to have been removed. That is, sulfur remains in the reforming catalyst up to a certain amount even if it is initially oxidized, but when it exceeds that, it is oxidized and removed together with surrounding carbon.

  The hydrogen sulfide during reforming was measured with a detector tube, but could not be detected (the amount was 1000 ppb or less). Hydrogen sulfide during recovery of the reforming catalyst was measured with a hydrogen sulfide meter based on the ultraviolet absorption method. For easy understanding, FIG. 22 shows an image diagram of deterioration and recovery of the reforming catalyst for reference. E85 indicates a fuel containing 85% by volume of ethanol and 15% by volume of gasoline. In this case, if there is no oxygen, E85 is covered with carbon and the activity is lost.

  23 to 25 show the catalyst examined this time (made of cerium oxide, zirconium oxide, and aluminum oxide and carrying 2 wt% of Rh (rhodium) as a noble metal) and the catalyst examined earlier (in FIG. 12). A comparison of the reformed catalysts studied, in which a cordierite honeycomb is loaded with 240 g / L zirconia-based support and 2 g / L of Rh (rhodium) is shown. As shown in FIG. 25, the recovery rate is the hydrogen concentration B in the reformed gas in a state recovered from the initial state after deterioration (after t seconds) with respect to the hydrogen concentration A in the reformed gas in the initial state. The ratio is as follows. As shown in FIG. 23, when the reforming catalyst is recovered at 650 ° C., when the oxygen concentration at the time of recovery is high, both have the same recovery rate, but when the oxygen concentration at the time of recovery is low The catalyst examined this time has a higher recovery rate than the catalyst examined last time. Further, as shown in FIG. 24, when the oxygen concentration at the time of recovery is recovered at 0.5% by volume, when the temperature at the time of recovery is high (600 ° C. or higher), both have the same recovery rate. However, when the temperature at the time of recovery is low (500 ° C. or higher and lower than 600 ° C.), the catalyst examined this time has a higher recovery rate than the catalyst examined earlier. Thus, it was found that the catalyst examined this time can be sufficiently recovered at low oxygen concentration and low temperature. Therefore, in this case, the temperature at the time of recovery of the reforming catalyst should be 500 ° C. or higher.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited above, Of course, it can change and implement variously within the range which does not deviate from the main point. .

10 reformed gas generator 20 reforming pump (part of reforming raw material supply unit)
22 Reformer injector (part of reforming raw material supply unit)
32 ECU (control unit)
48 Upstream EGR passage (part of oxygen-containing gas supply section)
50 Downstream EGR passage (part of reformed gas supply unit)
52 Cooler (part of reformed gas supply unit)
54 EGR valve (part of oxygen-containing gas supply part, part of reformed gas supply part)
60 Exhaust catalyst (heating unit)
62 Reforming Catalyst 100, 200, 300 Reformed Gas Combustion Engine System

Claims (15)

A reforming catalyst that undergoes a reforming reaction that generates a reformed gas containing hydrogen from a reformed raw material containing sulfur and hydrocarbons by being heated; and
A heating unit for heating the reforming catalyst using thermal energy of exhaust gas discharged from the engine;
A reforming material supply unit for supplying the reforming material to the reforming catalyst;
An oxygen-containing gas supply unit for supplying an oxygen-containing gas to the reforming catalyst;
A reforming gas generating function for supplying the reforming material to the reforming catalyst by the reforming material supply unit so that the reforming gas is generated by the reforming catalyst; Stop supply of the reforming raw material to the reforming catalyst by the reforming raw material supply unit when the temperature is lower than the temperature range in which sulfur deposited on the reforming catalyst with combustion can be removed by combustion. In addition, the oxygen-containing gas is supplied to the reforming catalyst by the oxygen-containing gas supply unit, so that the reforming catalyst recovers the activity of the reforming catalyst by burning and removing carbon and hydrocarbons deposited on the reforming catalyst. A controller that selectively executes the catalyst activity recovery function;
A reformed gas generation apparatus comprising: The reforming raw material is ethanol mixed gasoline,
The controller, as the reforming catalyst activity recovery function, starts the activity recovery of the reforming catalyst when the temperature of the reforming catalyst is 500 to 700 ° C., and the temperature of the reforming catalyst is 700 Executing a function of stopping the activity recovery of the reforming catalyst when the temperature exceeds
The reformed gas production | generation apparatus of Claim 1. The control unit stops the supply of the oxygen-containing gas to the reforming catalyst by the oxygen-containing gas supply unit when the temperature of the reforming catalyst exceeds 700 ° C. as the reforming catalyst activity recovery function Execute the function
The reformed gas production | generation apparatus of Claim 2. The oxygen-containing gas supply unit supplies a part of the exhaust gas discharged from the engine as the oxygen-containing gas to the reforming catalyst and then introduces it into the engine.
The reformed gas production | generation apparatus as described in any one of Claims 1-3. The engine is an engine for driving a vehicle,
The oxygen-containing gas supply unit supplies a part of the exhaust gas discharged from the engine to the reforming catalyst as the oxygen-containing gas,
The control unit executes the reforming catalyst activity recovery function when the vehicle is decelerating,
The reformed gas production | generation apparatus as described in any one of Claims 1-4. The control unit executes the reforming catalyst activity recovery function when the deposition state of the carbon and the hydrocarbon in the reforming catalyst reaches a predetermined state.
The reformed gas production | generation apparatus as described in any one of Claims 1-5. The oxygen-containing gas supply unit supplies the oxygen-containing gas whose oxygen concentration is 0.1 to 1.0% by volume on a time average to the reforming catalyst.
The reformed gas production | generation apparatus as described in any one of Claims 1-6. Engine,
The reformed gas generator according to any one of claims 1 to 7,
A reformed gas supply unit for supplying the reformed gas generated by the reformed gas generator to the engine;
A reformed gas combustion engine system. The temperature of the reforming catalyst in which the reforming reaction for generating the reformed gas containing hydrogen from the reforming raw material containing sulfur and hydrocarbons is performed by heating is performed according to the reforming catalyst. By stopping the supply of the reforming raw material to the reforming catalyst and supplying an oxygen-containing gas to the reforming catalyst when the temperature is lower than the temperature range in which sulfur deposited on the catalyst can be burned and removed. , To recover the activity of the reforming catalyst by burning and removing carbon and hydrocarbons deposited in the reforming catalyst in the reforming reaction,
A method for recovering the activity of a reforming catalyst. Using ethanol mixed gasoline as the reforming raw material, when the temperature of the reforming catalyst is 500 to 700 ° C, recovery of the activity of the reforming catalyst is started, and the temperature of the reforming catalyst exceeds 700 ° C. Stopping the recovery of the activity of the reforming catalyst,
The method for recovering the activity of the reforming catalyst according to claim 9. Stopping the supply of the oxygen-containing gas to the reforming catalyst when the temperature of the reforming catalyst exceeds 700 ° C .;
The method for recovering the activity of the reforming catalyst according to claim 10. A part of exhaust gas discharged from an engine of a vehicle on which the reforming catalyst is mounted is introduced into the engine after being supplied to the reforming catalyst as the oxygen-containing gas,
The method for recovering the activity of a reforming catalyst according to any one of claims 9 to 11. When the vehicle on which the reforming catalyst is mounted is decelerating and the temperature of the reforming catalyst is in a temperature range lower than the temperature range in which the sulfur can be burned and removed, the engine of the vehicle A part of the exhaust gas discharged is supplied to the reforming catalyst as the oxygen-containing gas to recover the activity of the reforming catalyst;
The method for recovering the activity of a reforming catalyst according to any one of claims 9 to 12. The temperature range in which the temperature of the reforming catalyst is lower than the temperature range in which the sulfur can be burnt and removed, when the precipitation state of the carbon and the hydrocarbon in the reforming catalyst is in a predetermined state. The oxygen-containing gas is supplied to the reforming catalyst to restore the activity of the reforming catalyst.
The method for recovering the activity of the reforming catalyst according to any one of claims 9 to 13. Supplying the oxygen-containing gas having an oxygen concentration of 0.1 to 1.0% by volume on a time average to the reforming catalyst;
The method for recovering the activity of the reforming catalyst according to any one of claims 9 to 14.

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