JP2018003801A - Fuel reformation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel reformation system capable of continuously executing a reforming operation regardless of an operation state of an engine.SOLUTION: A fuel reformation system 1 for producing a reformed fuel including alcohol by reforming a fuel mainly composed of hydrocarbon by using oxygen, includes a mixer 2 for producing a mixture of an oxydation gas and a fuel, a reforming reactor 3 in which a reforming reaction progresses under action of reforming catalyst and the reformed fuel is discharged from an outlet when the air-fuel mixture is supplied from the mixer 2, an oxidation gas supply device 4 for supplying a new oxidation gas not passing through the reforming reactor 3 to the mixer 2, a gas-liquid separator 73 for separating the reformed fuel of gas-liquid mixture discharged from the outlet of the reforming reactor 3 into a gas phase and a condensate phase, and a gas phase recirculation device 8 for supplying at least a part of the reformed fuel of the gas phase separated by the gas-liquid separator 73 to the mixer 2 as a recirculated oxidation gas.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel reforming system for reforming a fuel mainly composed of hydrocarbons to improve the octane number. More specifically, the present invention relates to a fuel reforming system that can stably reform fuel regardless of the operating state of an internal combustion engine.

  In recent years, with the aim of further improving the thermal efficiency of an internal combustion engine, research on techniques for increasing the compression ratio of the internal combustion engine has been advanced. For example, when the compression ratio is increased in a gasoline engine, the end gas (unburned mixture at a location away from the spark plug) is likely to cause so-called knocking in which self-ignition is caused by compression before the flame reaches the entire combustion chamber. Become. Therefore, to achieve high efficiency of the internal combustion engine, it is important to avoid the occurrence of knocking while maintaining a high compression ratio. Many internal combustion engines with a high compression ratio that have been proposed in recent years often suppress the occurrence of knocking by delaying the ignition timing. However, if the ignition timing is delayed, the thermal efficiency is lowered, so it is not sufficient as a technique for suppressing the occurrence of knocking.

  Therefore, attention has been focused on a technique for improving the octane number of fuel used in an internal combustion engine by reforming fuel supplied to the vehicle from the outside on the vehicle. For example, Patent Document 1 proposes a fuel reforming system that reforms gasoline and generates reformed fuel containing alcohol, which can be mounted on a vehicle, by the present applicant.

  The fuel reforming system described in Patent Document 1 is a mixer that generates a mixture by mixing fuel mainly composed of hydrocarbon and air, and reforms the generated mixture under the action of a reforming catalyst. A reforming reactor for generating alcohol, a condenser for condensing the reformed fuel in a gas-liquid mixed state generated in the reforming reactor, and a reformed fuel tank for storing the condensed reformed fuel. .

International Publication No. 2015/076305

  When fuel and air are supplied to the reforming reactor as described above, gas phase fuel vapor is also generated from the reforming reactor together with liquid phase reformed fuel containing alcohol. For this reason, in order to continuously produce reformed fuel in the reforming reactor, it is necessary to appropriately process the fuel vapor generated by the reforming. Further, as a method for treating fuel vapor, it is known that fuel vapor is released into intake air directly or via a canister by using intake negative pressure of the internal combustion engine and used for combustion of the internal combustion engine.

  However, in this processing method, the timing at which fuel vapor can be processed is limited by the operating state of the internal combustion engine. For this reason, when this processing method is applied to process the fuel vapor generated in the fuel reforming system, it is necessary to use a large canister so that a sufficient amount of fuel vapor can be adsorbed. In order to avoid an increase in the size of the canister, the supply of fuel and air to the reforming reactor may be temporarily stopped in accordance with changes in the operating state of the internal combustion engine. It becomes impossible to continuously reform. Moreover, even if the supply of fuel or air to the reforming reactor is stopped, the generation of fuel vapor does not stop immediately.

  An object of the present invention is to provide a fuel reforming system capable of continuously performing a reforming operation regardless of the operating state of the internal combustion engine.

  (1) A fuel reforming system of the present invention (for example, a fuel reforming system 1 described later) is a system that reforms a hydrocarbon-based fuel using oxygen to produce a reformed fuel containing alcohol. A mixture (for example, a mixer 2 to be described later) that generates a mixture of oxidizing gas and fuel, and when the mixture is supplied from the mixer, a reforming reaction is performed under the action of a reforming catalyst. And a reforming reactor (e.g., reforming reactor 3 described later) that discharges reformed fuel from the outlet, and an oxidizing gas supply device that supplies oxidizing gas that has not passed through the reforming reactor to the mixer ( For example, an oxidizing gas supply device 4) described later and a gas-liquid separator (for example, a gas-liquid separator 73 described later) for separating the gas-liquid mixed reformed fuel discharged from the outlet into a gas phase and a condensed phase. And at least part of the gas-phase reformed fuel separated by the gas-liquid separator The vapor recirculation device for supplying to the mixer as an oxidizing gas (e.g., gas phase recirculation device 8 will be described later) provided with a.

  (2) In this case, the fuel reforming system could not condense with the condenser (for example, the condenser 74 described later) that condenses the reformed fuel discharged from the gas-liquid separator and the condenser. A steam processing device (for example, a second steam processing device 78, which will be described later) for supplying gas-phase reformed fuel into an intake passage (for example, a later-described intake passage E1) of an internal combustion engine (for example, an engine E, which will be described later); It is preferable to further comprise.

  (3) In this case, depending on the operating state of the internal combustion engine, an oxidizing gas supply amount from the oxidizing gas supply device to the mixer and a reflux oxidizing gas supply amount from the vapor phase reflux device to the mixer It is preferable to further include a control device for controlling.

  (4) In this case, it is preferable that the control device increases the supply amount of the reflux oxidizing gas when the internal combustion engine is stopped than when the internal combustion engine is operating.

  (5) In this case, the control device matches the oxidizing gas supply amount and the reflux oxidizing gas supply amount when the internal combustion engine is stopped, compared to when the internal combustion engine is operating. It is preferable to increase the ratio of the reflux oxidizing gas supply amount to the total oxidizing gas supply amount.

  (1) In the present invention, the reformed fuel discharged from the reforming reactor in a gas-liquid mixed state is separated into a gas phase and a condensed phase by the gas-liquid separator, and the gas phase containing fuel vapor and unreacted oxygen At least a part of the reformed fuel is again supplied as refluxing oxidant gas to the reformer mixer. By recirculating the gas-phase reformed fuel generated in the reforming reactor in this way, the amount of fuel vapor to be processed in the internal combustion engine is reduced without temporarily stopping the reforming operation in the reforming reactor. be able to. Therefore, according to the present invention, the reforming operation can be continuously performed regardless of whether the operation state of the internal combustion engine is a state in which the fuel vapor can be processed. In addition, by reducing at least part of the reformed fuel in the gas phase to the mixer to reduce the amount of fuel vapor to be processed by the internal combustion engine, fluctuations in the amount of oxygen and fuel in the cylinder of the internal combustion engine are reduced. Therefore, the reforming operation can be performed without adversely affecting the air-fuel ratio control of the internal combustion engine. In addition, the size of the canister that temporarily adsorbs the fuel vapor during processing by the internal combustion engine can be reduced. Further, in the present invention, the gas-phase reformed fuel that has been heated through the reforming reactor is supplied again to the mixer, so that the air-fuel mixture is mixed in the mixer as compared with the case of supplying freshly cooled oxidizing gas. Energy necessary for raising the temperature can be suppressed.

  (2) In the present invention, the reformed fuel discharged from the gas-liquid separator is condensed by the condenser, and the gas phase reformed fuel that has not been condensed by the condenser is converted into the intake passage of the internal combustion engine by the steam processing device. Supply in. Therefore, in the present invention, the amount of reformed fuel flowing into the condenser is reduced by supplying again to the mixer at least a part of the reformed gas in the gas phase separated by the gas-liquid separator by the gas-phase reflux apparatus. Therefore, the consumption of energy necessary for condensing the reformed fuel with the condenser can be suppressed, and the size of the condenser can be reduced.

  (3) Since the steam processing device supplies gas containing fuel vapor to the intake passage of the internal combustion engine, the amount of gas that can be processed by the steam processing device varies depending on the operating state of the internal combustion engine. Further, when the amount of refluxing oxidizing gas supplied from the gas phase reflux device is increased, the amount of gas to be processed by the steam processing device is reduced, but an oxidizing gas with a relatively high oxygen concentration that can be supplied from the oxidizing gas supply device by that amount. The amount of supply must be reduced. Therefore, in the present invention, the oxidizing gas supply amount from the oxidizing gas supply device and the reflux oxidizing gas supply amount from the gas phase recirculation device according to the operating state of the internal combustion engine correlated with the amount of gas that can be processed by the steam processing device. Control. Thus, the oxidizing gas supply amount and the reflux oxidizing gas supply amount can be changed in accordance with the change in the gas processing capacity in the steam processing apparatus.

  (4) In the present invention, when the internal combustion engine is stopped, the reflux oxidizing gas supply amount is increased more than when the internal combustion engine is operating. As a result, even when the internal combustion engine is stopped and the gas-phase reformed fuel cannot be supplied from the steam processing device to the intake passage, the reforming operation in the reforming reactor is continued and sent to the steam processing device. The amount of gas phase reformed fuel produced can be reduced.

  (5) In the present invention, when the internal combustion engine is stopped, the ratio of the recirculated oxidizing gas supply amount to the total oxidizing gas supply amount is increased more than when the internal combustion engine is operating. As a result, even when the internal combustion engine is stopped and the gas-phase reformed fuel cannot be supplied from the steam processing device to the intake passage, the reforming operation in the reforming reactor is continued and sent to the steam processing device. The amount of gas phase reformed fuel produced can be reduced.

It is a figure showing composition of a fuel reforming system concerning one embodiment of the present invention. The final results are obtained when the reformed fuel that has been reacted with the unreformed fuel is mixed at a predetermined ratio and reformed, and when the reformed fuel that has been reacted with the unreformed fuel is reformed without mixing. It is the figure which compared the oxidation progress per hour of the obtained reformed fuel. It is a flowchart which shows the procedure which supplies oxidizing gas, a fuel, etc. to a mixer using an oxidizing gas supply apparatus, a gaseous-phase reflux apparatus, etc.

An embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a fuel reforming system 1 according to the present embodiment. The fuel reforming system 1 is mounted on a vehicle (not shown). The fuel reforming system 1 includes a reforming reactor 3 and includes alcohol, ketone, and the like by the reforming reactor 3 using a hydrocarbon-based fuel (for example, gasoline) and air as an oxidizing gas. The reformed fuel is generated, and the reformed fuel is supplied to the engine E that is a power generation source of the vehicle. FIG. 1 shows only the configuration of the fuel reforming system 1, the engine E, and its intake system. In the intake passage E1 of the engine E1, an air cleaner box E2 provided with an air filter for removing foreign matters in the intake air in order from the upstream side, a supercharger E3 that compresses intake air using exhaust energy, and an intake throttle valve E4. In FIG. 1, the path and piping of the condensed phase material are mainly indicated by solid arrows, and the path and piping of the gas phase material are mainly indicated by broken arrows.

  The fuel reforming system 1 includes a mixer 2 that generates a mixture of oxidizing gas and fuel, a reforming reactor 3 that undergoes a reforming reaction when the mixture is supplied, and discharges the reformed fuel from an outlet thereof. The oxidizing gas supply device 4 that supplies oxygen-containing oxidizing gas to the mixer 2, the unreformed fuel supply device 5 that supplies unreformed fuel supplied from outside the vehicle to the mixer 2, and the mixer 2 are modified. Main catalyst supply device 6 for supplying a catalyst for promoting the reforming reaction in the quality reactor 3, and reformed fuel circulation for recovering the reformed fuel discharged from the reforming reactor 3 and supplying it again to the mixer 2 An apparatus 7, a gas phase recirculation apparatus 8 for mainly recovering the reformed fuel discharged from the reforming reactor 3 and supplying it again to the mixer 2, and these electronic control units (hereinafter referred to as “ ECU ”) 9).

  The oxidant gas supply device 4 includes a main supply pipe 41, a sub supply pipe 42, an introduction path switching valve 43, a sub air pump 45, and an oxidant gas processing device 46, and these are used to define the intake passage E1. A part of the flowing intake air is supplied to the mixer 2 as an oxidizing gas.

  The main supply pipe 41 is a pipe that connects the supercharger E3 and the intake throttle valve E4 to the mixer 2 in the intake passage E1. The intake air flowing through the intake passage E1 and compressed by the supercharger E3 is supplied to the mixer 2 via the main supply pipe 41. The sub supply pipe 42 is a pipe connecting the downstream side of an air filter (not shown) of an air cleaner box E2 provided on the upstream side of the supercharger E3 in the intake passage E1. A part of the intake air flowing on the upstream side of the supercharger E3 in the intake passage E1 is supplied to the mixer 2 via the sub supply pipe 42. The sub air pump 45 is provided in the sub supply pipe 42, compresses a part of the intake air flowing upstream of the supercharger E 3 in the intake passage E 1 in accordance with a control signal from the ECU 9, and compresses the compressed air into the mixer 2. To supply. In the intake passage E1, the upstream side of the supercharger E3 has a lower pressure than the downstream side of the supercharger E3. Therefore, the intake air on the downstream side of the supercharger E3 can be supplied to the mixer 2 without using a pump, but the intake air on the upstream side of the supercharger E3 is mixed unless the sub air pump 45 is driven. Cannot be supplied to vessel 2. In the following, the case where the sub supply pipe 42 is connected to the air cleaner box E2 upstream of the supercharger E3 will be described. However, the connection destination of the sub supply pipe 42 may be upstream of the air cleaner box E2 or outside the intake passage. Good.

  As described above, the oxidizing gas supply device 4 includes the main supply pipe 41 through which intake air from the downstream side of the supercharger E3 flows in the intake passage E1, and the intake air from the upstream side of the supercharger E3 in the intake passage E1. There are provided two intake introduction paths for the sub-supply pipe 42 through which the gas flows. The introduction path switching valve 43 is a three-way valve provided at a branch portion of the sub supply pipe 42 in the main supply pipe 41. The introduction path switching valve 43 passes the intake introduction path on the downstream side of the supercharger E3 (main supply pipe 41 side) and the upstream side of the supercharger E3 (sub supply pipe 42 side) according to a control signal from the ECU 9. And switch selectively. That is, when the introduction path switching valve 43 is set on the downstream side of the supercharger E3, the intake air compressed by the supercharger E3 is supplied to the mixer 2. Further, when the introduction path switching valve 43 is set on the upstream side of the supercharger E3 and the sub air pump 45 is driven, intake air on the upstream side of the supercharger E3 is supplied to the mixer 2.

  The oxidizing gas processing device 46 is provided on the downstream side of the introduction path switching valve 43 in the main supply pipe 41 and reinforces the oxidizing power of the air that flows through the main supply pipe 41 and is supplied to the mixer 2. More specifically, the oxidizing gas processing device 46 includes an oxygen-enriched film 461 provided in the main supply pipe 41 and an ozone generator 462 provided on the downstream side of the oxygen-enriched film 461 in the main supply pipe 41. And comprising.

  The oxygen-enriched film 461 removes nitrogen in the intake air (air) flowing through the main supply pipe 41, thereby increasing the oxygen concentration of the intake air. As a material used for the oxygen-enriched membrane 461, a known material such as a silicon membrane or a hollow fiber membrane is used. Further, the ozone generator 462 excites a part of oxygen in the intake air flowing through the main supply pipe 41 in accordance with a control signal from the ECU 9 to generate ozone.

  Next, a specific control procedure for supplying the oxidizing gas to the mixer 2 using the oxidizing gas supply device 4 will be described. As described above, the oxidizing gas supply device 4 includes two intake introduction paths, a path acquired from the downstream side of the supercharger E3 and a path acquired from the upstream side of the supercharger E3. The ECU 9 controls the introduction path switching valve 43 according to the operating state of the engine E, and supplies the intake air as the oxidizing gas to the mixer 2 while selecting an appropriate path.

  More specifically, for example, when the operating state of the engine E is in a supercharging region where intake air is compressed by the supercharger E3, the ECU 9 sets the introduction path switching valve 43 on the downstream side of the supercharger E3. To do. Accordingly, a part of the intake air compressed by the supercharger E3 is supplied to the mixer 2 via the main supply pipe 41. Further, the ECU 9 drives the ozone generator 462 to generate ozone in the oxidizing gas while the oxidizing gas flows through the main supply pipe 41 and is supplied to the mixer 2. Thereby, when the operating state of the engine E is within the supercharging region, a part of the intake air can be supplied to the mixer 2 without the sub air pump 45 being driven.

  When the operating state of the engine E is in the non-supercharging region where the intake air is not compressed by the supercharger E3, the ECU 9 sets the introduction path switching valve 43 on the upstream side of the supercharger E3 and the sub air Turn pump 45 on. Thereby, a part of the intake air on the upstream side of the supercharger E3 is supplied to the mixer 2 via the sub supply pipe 42 and the main supply pipe 41. Further, the ECU 9 drives the ozone generator 462 to generate ozone in the oxidizing gas while the oxidizing gas flows through the main supply pipe 41 and is supplied to the mixer 2 as described above. Thereby, even if the operating state of the engine E is in the non-supercharging region, the oxidizing gas whose flow rate is adjusted by the sub air pump 45 can be supplied to the mixer 2.

  As described above, the oxidizing gas supplied by the oxidizing gas supply device 4 uses intake air or outside air, and therefore has not passed through the reforming reactor 3 even once. Therefore, hereinafter, the oxidant gas supplied by the oxidant gas supply device 4 is also referred to as a new oxidant gas in order to distinguish it from the oxidant gas supplied by the gas-phase reflux device 8.

  The unreformed fuel supply device 5 includes a fuel supply fuel tank 51, a fuel supply pipe 52, a feed pump 53, a fuel supply valve 54, a high-pressure fuel pump 55, and a direct injector 56, and these are used. Thus, unreformed fuel that has not yet passed through the reforming reactor 3 is supplied to the mixer 2 and the engine E.

  The fuel supply fuel tank 51 stores unreformed fuel (for example, gasoline) mainly composed of hydrocarbons. The unreformed fuel supplied from outside the vehicle is first supplied to the fuel supply fuel tank 51. The fuel supply pipe 52 is a pipe that connects the fuel supply fuel tank 51 and the direct injector 56 provided in the mixer 2 and the engine E. Unreformed fuel flows through the fuel supply pipe 52 and is supplied to the inside of the mixer 2 or directly to the injector 56.

  The feed pump 53 pressure-feeds unreformed fuel stored in the fuel supply fuel tank 51 into the fuel supply pipe 52 in response to a control signal from the ECU 9. The fuel supply valve 54 is provided on the mixer 2 side of the fuel supply pipe 52 and opens and closes in response to a control signal from the ECU 9. As a result, an amount of unreformed fuel corresponding to the open / close period is supplied from the fuel supply valve 54 into the mixer 2. When the ECU 9 reforms the fuel in the reforming reactor 3, the ratio of the oxygen in the reforming reactor 3 to the fuel that is a combination of unreformed fuel and a reformed reformed fuel that will be described later is determined. The feed pump 53 and the fuel supply valve 54 are driven so as to be maintained within a predetermined target range, and the flow rate of unreformed fuel supplied to the mixer 2 is controlled.

  The high-pressure fuel pump 55 uses the rotation of the crankshaft of the engine E to compress the low-pressure unreformed fuel supplied through the fuel supply valve 54 to a higher pressure and supply the compressed fuel directly to the injector 56. The direct injector 56 opens and closes in response to a control signal from the ECU 9 and directly injects the high-pressure fuel supplied from the high-pressure fuel pump 55 into the cylinder of the engine E. Note that a description of a specific procedure of fuel injection control in the engine E is omitted.

  The refueling fuel tank 51 is provided with an unreformed fuel vapor processing device 57 that processes fuel vapor generated in the tank 51. The unreformed fuel vapor processing device 57 is provided in the vapor passage 571 for connecting the fuel supply fuel tank 51 and the air cleaner box E2 of the intake passage E1 to the downstream side of the connection portion of the sub supply pipe 42. A canister 572. The fuel vapor generated from the unreformed fuel stored in the fuel supply fuel tank 51 is once adsorbed by the canister 572. The fuel vapor adsorbed by the canister 572 is purged at a timing when a negative pressure is generated in the intake passage E1, and is supplied to the intake passage E1 through the steam passage 571.

  The main catalyst supply device 6 includes a main catalyst tank 61, a catalyst supply pipe 62, and a catalyst metering pump 64, and constitutes a reforming catalyst that promotes a reforming reaction in the reforming reactor 3 by using these. The main catalyst is fed to the mixer 2. The main catalyst tank 61 stores a liquid main catalyst supplied from outside the vehicle. The specific structure of the main catalyst will be described later in detail together with the structure of the promoter described later. The catalyst supply pipe 62 is a pipe that connects the main catalyst tank 61 and the mixer 2. The main catalyst flows through the catalyst supply pipe 62 and is supplied into the mixer 2. The catalyst metering pump 64 measures the main catalyst stored in the main catalyst tank 61 in accordance with a control signal from the ECU 9 and supplies it to the mixer 2 with a predetermined supply pressure. The ECU 9 drives the catalyst metering pump 64 to adjust the flow rate of the fuel supplied to the mixer 2 when reforming the fuel by supplying unreformed fuel, oxidizing gas, or the like to the reforming reactor 3. The main catalyst is supplied at a corresponding flow rate.

  The mixer 2 is filled with a mixing container 25 provided with an oxidizing gas introduction part 21, an unreformed fuel introduction part 22, a catalyst introduction part 23, and a reformed fuel introduction part 24, and the inside of the mixing container 25. A particulate substance or a porous substance (not shown) and a heater (not shown) for heating the fluid introduced into the mixing container 25 are provided. A main supply pipe 41 of an oxidant gas supply device is connected to the oxidant gas introduction part 21. The oxygen-containing oxidizing gas whose flow rate has been adjusted by the oxidizing gas supply device 4 or the gas-phase reflux device 8 described later is supplied into the mixing container 25 via the oxidizing gas introduction unit 21. A fuel supply pipe 52 of the unreformed fuel supply device 5 is connected to the unreformed fuel introduction unit 22. The unreformed fuel whose flow rate is adjusted by the unreformed fuel supply device 5 is supplied into the mixing container 25 through the unreformed fuel introduction unit 22. A catalyst supply pipe 62 of the main catalyst supply device 6 is connected to the catalyst introduction part 23. The main catalyst whose flow rate is adjusted by the main catalyst supply device 6 is supplied into the mixing container 25 via the catalyst introduction part 23. A reformed fuel supply pipe 75 (described later) of the reformed fuel circulation device 7 is connected to the reformed fuel introduction unit 24. The reformed fuel whose flow rate has been adjusted by the reformed fuel circulation device 7 is supplied into the mixing container 25 via the reformed fuel introduction unit 24.

  As the particulate matter in the mixer 2, for example, quartz stone, silicon dioxide, zeolite or the like is used. As the porous material, for example, porous stainless steel that is a sintered body of stainless steel, other porous metals, or the like is used. The fluid introduced from each of the introduction portions 21 to 24 is uniformly mixed inside the mixing container 25, and the air-fuel mixture thus generated is evenly pressurized to the inlets of the plurality of air-fuel mixtures of the reforming reactor 3. These particulate substances and porous substances are evenly filled in the mixing container 25 so as to be supplied at the same time.

  While the fluid such as air and unreformed fuel introduced into the mixing container 25 through the introduction parts 21 to 24 is heated to a temperature suitable for the reforming reaction in the reforming reactor 3 by the heater, The flow is dispersed, transformed, and converted (rotated) by the particulate material or the porous material provided in the mixing container 25, and a uniform air-fuel mixture is generated. The air-fuel mixture generated inside the mixing vessel 25 is pushed out to the inlets of the plurality of air-fuel mixtures of the reforming reactor 3 connected to the mixer 2.

  The reforming reactor 3 includes a plurality of reaction tubes (not shown) that serve as a flow path for the air-fuel mixture generated by the mixer 2, and a cylindrical body 32 that accommodates the plurality of reaction tubes. 32 is a multi-tube heat exchanger in which a refrigerant flow path through which a refrigerant flows around the reaction tube is formed.

  The inlet of each reaction tube communicates with the inside of the mixer 2 described above. Each reaction tube is filled with a particulate material or a porous material carrying a promoter that constitutes a reforming catalyst for promoting the reforming reaction. The air-fuel mixture pushed up to the inlet of each reaction tube by the mixer 2 at an equal pressure flows through each reaction tube and is discharged from the outlet. The air-fuel mixture formed by mixing the air, the main catalyst, the unreformed fuel, and the reformed fuel at a predetermined ratio in the mixer 2 flows under the action of the reforming catalyst in the process of flowing inside each reaction tube 31. Then, the reforming reaction using oxygen proceeds and is discharged from the outlet as a reformed fuel in a gas-liquid mixed state. In addition, each reaction tube 31 may be provided in parallel with the horizontal direction so that the air-fuel mixture supplied from the mixer 2 flows along the horizontal direction, or the air-fuel mixture supplied from the mixer 2 has its own weight. The outlet of each reaction tube may be made higher than the inlet and parallel to the vertical direction so that it flows from the lower side to the upper side along the vertical direction.

  A refrigerant introduction part 33 for receiving a refrigerant supplied from the outside is provided on the outlet side of the reaction tube in the body 32, and a refrigerant for discharging the refrigerant from the inside of the body 32 on the inlet side of the reaction tube in the body 32. A discharge part 34 is provided. The refrigerant introduction part 33 and the refrigerant discharge part 34 are connected to a cooling water circulation circuit (not shown) through which cooling water for cooling the engine circulates. As a result, cooling water whose temperature is adjusted by the radiator flows using the engine as a heat source in the body 32.

  The temperature of the cooling water supplied to the reforming reactor 3 is preferably in the range of 70 to 110 ° C., for example. When the temperature of the cooling water is less than 70 ° C., the effect of increasing the reforming reaction rate in each reaction tube is reduced. Moreover, the effect of increasing the reforming reaction rate increases as the temperature of the cooling water increases. However, when the temperature of the cooling water exceeds 110 ° C., it becomes difficult to use the engine cooling water. Therefore, when it is time to reform the fuel using the reforming reactor 3 and the temperature of the cooling water is within the above temperature range, the ECU 9 drives the cooling water pump of the cooling water circulation circuit to reform the fuel. When the cooling water is circulated in the reactor 3 and the temperature of the cooling water is outside the above temperature range, the cooling water pump is stopped and the circulation of the cooling water is stopped. As a result, when the reforming reaction in the reaction tube proceeds and the temperature in the reaction tube has already reached a high temperature, the cooling water acts to cool the reaction tube, and the temperature in the reaction tube is reduced at the initial stage of the reforming reaction. When the temperature is low, the cooling water acts to warm the reaction tube. Thereby, the reforming reaction rate of the air-fuel mixture in each reaction tube is improved.

  Next, specific configurations of the main catalyst and the cocatalyst will be described. As the main catalyst supplied to each reaction tube via the mixer 2 by the main catalyst supply device 6 described above, one that acts to extract hydrogen atoms from hydrocarbons in gasoline to generate alkyl radicals is used. . Specifically, an N-hydroxyimide group-containing compound having an N-hydroxyimide group is used as the main catalyst. Among these, N-hydroxyphthalimide (hereinafter referred to as “NHPI”) and NHPI derivatives are preferably used since the above-described effects are remarkable.

  The co-catalyst supported inside the reaction tube 31 has an ability to reduce an alkyl hydroperoxide generated from an alkyl radical to generate an alcohol, and to react this alcohol with the alkyl radical to generate a ketone. What you have is used. Specifically, a transition metal compound is used as the promoter. Among these, a compound selected from the group consisting of a cobalt compound, a manganese compound, and a copper compound is preferably used. Cobalt acetate (II) or the like is used as the cobalt compound, manganese (II) acetate or the like is used as the manganese compound, and copper (I) chloride or the like is used as the copper compound.

In each reaction tube of the reforming reactor, the following reforming reaction proceeds under the action of the reforming catalyst comprising the main catalyst and the cocatalyst as described above. First, as shown in the following reaction formula (1), the reforming reaction of the present embodiment is initiated by a hydrogen abstraction reaction in which hydrogen atoms are extracted from hydrocarbons in gasoline to generate alkyl radicals. This hydrogen abstraction reaction proceeds by the action of the main catalyst, radicals, oxygen molecules and the like.
[Chemical 1]
RH-> R ... Reaction formula (1)
[In Reaction Formula (1), RH represents a hydrocarbon, and R. represents an alkyl radical. ]

Next, as shown in the following reaction formula (2), the alkyl radical generated by the hydrogen abstraction reaction is combined with oxygen molecules to generate an alkyl peroxy radical.
[Chemical formula 2]
R · + O ₂ → ROO · ... Reaction formula (2)
[In Reaction Formula (2), O ₂ represents an oxygen molecule, and ROO · represents an alkyl peroxy radical. ]

Next, as shown in the following reaction formula (3), the alkyl peroxy radical generated by the reaction formula (2) pulls out hydrogen atoms from hydrocarbons contained in gasoline to generate an alkyl hydroperoxide.
[Chemical formula 3]
ROO · + RH → ROOH + R · ... Reaction formula (3)
[In reaction formula (3), ROOH represents alkyl hydroperoxide. ]

Next, as shown in the following reaction formula (4), the alkyl hydroperoxide produced by the reaction formula (3) is reduced to an alcohol by the action of a promoter.
[Chemical formula 4]
ROOH → ROH ... Reaction formula (4)
[In the reaction formula (4), ROH represents an alcohol. ]

Moreover, the alkyl hydroperoxide produced | generated by Reaction formula (3) decomposes | disassembles into an alkoxy radical and a hydroxy radical by the effect | action of a promoter or a heat | fever as shown in following Reaction formula (5).
[Chemical formula 5]
ROOH → RO ・ + ・ OH ... Reaction formula (5)
[In reaction formula (5), RO / represents an alkoxy radical, and · OH represents a hydroxy radical. ]

Subsequently, the alkoxy radical produced | generated by Reaction formula (5) draws out a hydrogen atom from the hydrocarbon contained in gasoline, and produces | generates alcohol.
[Chemical 6]
RO · + RH → ROH + R · ... Reaction formula (6)

  As described above, hydrocarbons mainly contained in gasoline are oxidized and reformed and converted to alcohol. More specifically, since hydrocarbons contained in gasoline are hydrocarbons having 4 to 10 carbon atoms, these hydrocarbons are converted into alcohols having 4 to 10 carbon atoms. Of the alcohol ROH produced as described above, the majority is secondary alcohol R—CHOH—R ′.

Next, the secondary alcohol R—CHOH—R ′ produced as described above reacts with an alkyl radical such as an alkyl peroxy radical ROO. The alkyl radical R—C.OH—R ′ is generated.
[Chemical 7]
R-CHOH-R '+ ROO · → RC · OH-R' + ROOH
... Reaction formula (7)
[In Reaction Formula (7), R—CHOH—R ′ represents a secondary alcohol, and R—C · OH—R ′ represents a hydroxyalkyl radical. ]

Next, the hydroxyalkyl radical R—C.OH—R ′ is further reacted with an alkyl radical such as an alkyl peroxy radical ROO. -R 'is generated.
[Chemical 8]
RC-OH-R '+ ROO- → RC = O-R' + ROOH
... Reaction formula (8)
[In Reaction Formula (8), R—C═O—R ′ represents a ketone. ]

  As described above, in the fuel reforming system 1 of the present embodiment, gasoline supplied from the outside can be reformed into a high octane fuel containing ketone, and the octane number of the fuel can be improved.

  The reformed fuel circulation device 7 includes a reformed fuel tank 71, a reformed fuel recovery pipe 72, a gas-liquid separator 73, a condenser 74, a reformed fuel supply pipe 75, a circulation pump 76, a first A steam processing device 77 and a second steam processing device 78 are provided, and by using these, the reformed fuel is circulated in a circulation path including the reforming reactor 3.

  The gas-liquid separator 73 is connected to the outlet of each reaction tube of the reforming reactor 3, and the reformed fuel discharged from the outlet in a gas-liquid mixed state is separated into a gas phase and a condensed phase, and is separated from each other. Discharge to piping. More specifically, the gas-liquid separator 73 supplies the gas-phase reformed fuel to the gas-phase reflux device 8 to be described later via the gas-phase discharge section 731, and the condensed-phase reformed fuel for the condensed-phase reformed fuel. The fuel is discharged from the discharge unit 732 to the reformed fuel recovery pipe 72. When the gas-phase reformed fuel cannot be circulated in the gas-phase recirculation device 8 to be described later and there is no destination, the gas-phase reformed fuel is modified via the condensed-phase discharge unit 732. It is discharged to the quality fuel recovery pipe 72.

  The reformed fuel recovery pipe 72 is a pipe extending from the condensed phase discharge part 732 of the gas-liquid separator 73 to the reformed fuel tank 71. The reformed fuel that has been reacted and is discharged from the outlet of the reforming reactor 3 and discharged from the condensed phase discharge section 732 via the gas-liquid separator 73 is passed through the reformed fuel recovery pipe 72. It is supplied to the tank 71.

  The condenser 74 is provided in the reformed fuel recovery pipe 72, and uses a traveling wind generated by the traveling of the vehicle or a cooling wind generated by driving an electric fan (not shown), so that the gas-liquid separator 73 is used. The reformed fuel that has been reacted (mainly the condensed phase as described above) discharged from the condensed phase discharge portion 732 is condensed. The condenser 74 also has a function of a gas-liquid separator. Among the reformed fuels condensed by the condenser 74, the reformed fuel in the gas phase that cannot be completely condensed is supplied from the gas phase discharge unit 741 as described below. The two-phase steam treatment device 78 is discharged, and the condensed phase reformed fuel is supplied from the condensed phase discharge section 742 to the reformed fuel tank 71. If the second steam treatment device 78 described later cannot process the gas-phase reformed fuel and there is no place to go, the gas-phase reformed fuel is reformed via the reformed fuel recovery pipe 72. It is discharged to the fuel tank 71. Here, the condensed phase material includes alcohol and other by-products generated by the reforming reaction, and the gas phase material includes nitrogen, oxygen, and other by-products generated by the reforming reaction. Products etc. are included.

  The reformed fuel tank 71 is discharged from the reforming reactor 3 and stores mainly the reformed fuel in the condensed phase that has passed through the gas-liquid separator 73 and the condenser 74 as described above. The reformed fuel tank 71 is provided with an engine reformed fuel supply device 79 and a level sensor 711. The level sensor 711 detects the water level of the reformed fuel stored in the reformed fuel tank 71 and transmits a signal corresponding to the detected value to the ECU 9. In the ECU 9, the remaining amount of the reformed fuel in the reformed fuel tank 71 is grasped using the detection signal from the level sensor 711.

  The engine reformed fuel supply device 79 includes an engine fuel pump 791, an engine reformed fuel supply pipe 792, and a port injector 793. The engine reformed fuel supply pipe 792 is a pipe connecting the reformed fuel tank 71 and the port injector 793. The engine fuel pump 791 pressure-feeds the reformed fuel stored in the reformed fuel tank 71 to the port injector 793 via the engine reformed fuel supply pipe 792 in response to a control signal from the ECU 9. The port injector 793 is provided at the intake port of the engine E, and opens and closes in response to a control signal from the ECU 9. As a result, the amount of reformed fuel corresponding to the open / close period is supplied from the port injector 793 into the intake port of the engine E. Note that a description of a specific procedure of fuel injection control in the engine E is omitted.

  The reformed fuel supply pipe 75 is a pipe from the reformed fuel tank 71 to the reformed fuel introduction part 24 of the mixer 2. The reacted reformed fuel recovered in the reformed fuel tank 71 is supplied to the mixer 2 through the reformed fuel supply pipe 75. The reformed fuel supply pipe 75 is provided with a return pipe 751 branched from the reformed fuel supply pipe 75 and reaching the reformed fuel tank 71 again, and a control valve 752 provided at the branch portion. The control valve 752 is a three-way valve that switches the flow path of the reformed fuel between the mixer 2 side (hereinafter referred to as “supply side”) and the return pipe 751 side (hereinafter referred to as “return side”). The control valve 752 selectively switches the reformed fuel supply path between the supply side and the return side in accordance with a control signal from the ECU 9. The circulation pump 76 is provided in the reformed fuel tank 71, and the reformed fuel stored in the reformed fuel tank 71 in accordance with a control signal from the ECU 9 is supplied to the mixer 2 via the reformed fuel supply pipe 75. To pump. The ECU 9 sets the control valve 752 on the supply side and drives the circulation pump 76 when supplying the reacted reformed fuel having the effect of improving the reforming reaction rate as described later to the mixer 2. Thus, the flow rate of the reformed fuel supplied from the reformed fuel tank 71 to the mixer 2 is adjusted. On the other hand, when the ECU 9 determines that it is not necessary to supply the reformed fuel that has been reacted to the mixer 2, the control valve 752 is set to the return side and the supply of the reformed fuel to the mixer 2 is stopped. To do.

  The first steam processing device 77 includes a first steam passage 771 and a canister 772, and uses these to process fuel vapor generated from the reformed fuel stored in the reformed fuel tank 71. The first steam passage 771 is a pipe that connects the reformed fuel tank 71 and the downstream side of the connection portion of the sub supply pipe 42 in the air cleaner box E2 of the intake passage E1. Most of the fuel vapor generated from the reformed fuel stored in the reformed fuel tank 71 is once adsorbed by a canister 772 provided in the first steam passage 771. The fuel vapor adsorbed by the canister 772 is purged at a timing when a negative pressure is generated in the intake passage E1, and is supplied to the intake passage E1 through the first steam passage 771.

  Next, an experiment conducted to verify the effect of supplying the reformed fuel that has been reacted through the reforming reactor to the reforming reactor again using the reformed fuel circulation device 7 as described above and its The results will be described. In this experiment, the reforming reactor 3 was used to reform a predetermined amount of unreformed fuel over a predetermined time, and the oxidation progress degree correlated with the rate of increase in octane number of the finally obtained reformed fuel [ %] Was measured. In particular, in this experiment, when the unreformed fuel, the reformed fuel, the air, and the main catalyst are supplied to the reforming reactor 3 as in the fuel reforming system 1 of the above-described embodiment, The oxidation progress when a fixed amount of the reformed fuel that has been reacted is mixed and supplied to the reforming reactor 3, and unreformed fuel, air, main catalyst, and the like in the reforming reactor as in the conventional fuel reforming system. In other words, the degree of oxidation progress in the case of supplying unreformed fuel to the reforming reactor 3 without mixing the reformed fuel was obtained and compared.

  FIG. 2 shows that the unreacted reformed fuel is mixed with the unreformed fuel at a predetermined ratio (the ratio of the unreformed fuel is 0.25 when the reacted reformed fuel is 1.0). More specifically, the reformed fuel with the target octane number is mixed with unreformed fuel at a ratio of about 17%, and the reformed fuel that has reacted to the unreformed fuel is mixed. It is the figure which compared the oxidation progress per one hour of the reformed fuel finally obtained when it reformed without mixing (left side of Drawing 2).

  As shown in FIG. 2, when the reformed fuel that has been reacted is mixed with the unreformed fuel and supplied to the reforming reactor, only the unreformed fuel is supplied to the reforming reactor without mixing them. In comparison, the oxidation progress per hour increases. That is, when reforming a fuel using a reforming reaction using oxygen, the reacted reformed fuel has the effect of increasing the reforming reaction rate in the reforming reactor and promptly increasing the octane number. . This is considered that the reformed fuel that has been reacted has polarity, and thus the reaction rate is improved. In addition, when such a reformed fuel is supplied, the solubility of the main catalyst in the air-fuel mixture increases, thereby increasing the concentration of the main catalyst in the air-fuel mixture. For this reason, the reaction rate is improved. It is thought that.

  Returning to FIG. 1, the second steam processing device 78 includes an upstream steam pipe 781, a downstream steam pipe 782, and a flow path switching valve 783, and is not completely condensed by the condenser 74 from the gas phase discharge unit 741. Fuel vapor that has been discharged and is generated by continuously performing reforming operation in the reforming reactor 3 is supplied into the intake passage E1 of the engine E.

  The upstream steam pipe 781 is a pipe that connects the gas phase discharge part 741 of the condenser 74 and the upstream side of the intake throttle valve E4 and the supercharger E3 in the intake passage E1. The upstream flow path of the fuel vapor from the gas phase discharge part 741 to the upstream side of the supercharger E3 is constituted by this upstream steam pipe 781. The downstream steam pipe 782 is a pipe branched from the upstream steam pipe 781 and reaching the downstream side of the intake throttle valve E4 in the intake passage E1. The downstream path of the fuel vapor from the gas phase discharge part 741 to the downstream side of the intake throttle valve E4 is configured by combining the upstream steam pipe 781 and the downstream steam pipe 782. The flow path switching valve 783 is a three-way valve provided at a branch portion of the downstream steam pipe 782 in the upstream steam pipe 781. The flow path switching valve 783 blocks the flow of the fuel vapor from the gas phase discharge part 741 side to the intake passage E1 side in accordance with a control signal from the ECU 9, or any of the above-described upstream flow path and downstream flow path. Switch with.

  Here, a specific control procedure for processing the fuel vapor by the second steam processing device 78 will be described. While the oxidizing gas and fuel are supplied to the reforming reactor 3 and the reforming operation is continuously performed in the reforming reactor 3, a sufficient amount of gas phase is obtained by the gas-phase reflux device 8 described later. When the reformed fuel cannot be recirculated to the mixer 2, fuel vapor generated in the reforming operation is discharged from the gas phase discharge portion 741 of the condenser 74. Therefore, in order to perform the reforming operation continuously in the reforming reactor 3, the fuel vapor discharged from the gas phase discharge section 741 is supplied to an appropriate location in the intake passage E1 by the second steam processing device 78. To do.

  The ECU 9 performs the reforming operation in the reforming reactor 3, and therefore, depending on the operating state of the engine E, the fuel vapor may be discharged from the gas phase discharge unit 741 of the condenser 74. The flow path switching valve 783 is controlled. More specifically, when the engine E is operating and negative pressure is generated in the intake passage E1, the ECU 9 sets the flow path switching valve 783 to either the upstream flow path or the downstream flow path. Set. As a result, the fuel vapor discharged from the gas phase discharge portion 741 is introduced into the intake passage E1 using negative pressure and is used for combustion in the engine E.

  Further, when the engine E is stopped due to idle stop, no negative pressure is generated in the intake passage E1. Therefore, when the engine E is stopped, the ECU 9 sets the flow path switching valve 783 to the cutoff side. As a result, the fuel vapor discharged from the gas phase discharge part 741 cannot be supplied into the intake passage E1, and the destination is lost. However, even in such a case, according to the fuel reforming system 1 of the present embodiment, the fuel vapor that has lost its destination can be recirculated to the mixer 2 again by using the vapor phase recirculation device 8 described below. Therefore, it is not necessary to stop the reforming operation in the reforming reactor 3 while appropriately processing the fuel vapor.

  For example, when the flow path switching valve 783 is set to the shut-off side and the fuel vapor cannot be recirculated by the vapor phase recirculation device 8 described later, the fuel vapor is condensed into the condensed phase of the condenser 74. It flows into the reformed fuel tank 71 via the discharge part 742. However, since the fuel vapor flowing into the reformed fuel tank 71 is supplied into the intake passage E1 at an appropriate timing via the canister 772 by the first steam processing device 77, the flow path switching valve 783 is shut off. Even when set to, the reforming operation in the reforming reactor 3 can be continued.

  The gas-phase reflux apparatus 8 includes a gas-phase reflux pipe 81, a gas-phase reflux pump 82, and an oxidizing gas switching valve 83. By using these, the gas-phase reflux apparatus 8 discharges from the gas-phase discharge section 731 of the gas-liquid separator 73. At least a part of the reformed gas-phase reformed fuel is supplied to the mixer 2. Here, when an air-fuel mixture is supplied to the reforming reactor 3, the reformed fuel in a gas-liquid mixed state is discharged from the reforming reactor 3. The reformed fuel in the gas phase obtained by separating the reformed fuel with the gas-liquid separator 73 is used for the reforming reaction in the process of not only fuel vapor but also the mixture passing through the reforming reactor 3. It contains not a little unreacted oxygen. The gas-phase reflux apparatus 8 is a mixer that serves as an oxidizing gas so that at least a part of the oxygen-containing gas-phase reformed fuel obtained by the gas-liquid separator 73 is used for the reforming reaction in the reforming reactor 3 again. 2 is supplied. Hereinafter, the oxidizing gas supplied to the mixer 2 by the vapor phase reflux device 8 is also referred to as refluxing oxidizing gas in order to distinguish it from the new oxidizing gas supplied by the oxidizing gas supply device 4.

  The gas-phase reflux pipe 81 is a pipe that extends from the gas-phase discharge part 731 and is connected between the oxidizing gas processing device 46 and the mixer 2 in the main supply pipe 41 of the oxidizing gas supply device 4. The reflux oxidizing gas discharged from the gas phase discharge section 731 is supplied to the mixer 2 through the gas phase reflux pipe 81. The gas-phase recirculation pump 82 is provided in the gas-phase recirculation pipe 81, compresses the gas-phase reformed fuel discharged from the gas-phase discharge unit 731 in accordance with a control signal from the ECU 9, and mixes it as the recirculated oxidizing gas. To supply. In this way, by supplying the reflux oxidizing gas to the mixer 2 using the gas phase reflux device 8 while continuing the reforming operation in the reforming reactor 3, the gas is discharged from the gas phase discharge portion 741 of the condenser 74. The amount of fuel vapor to be processed by the second steam processing device 78 can be reduced to zero or reduced.

  The oxidant gas switching valve 83 is a three-way valve provided at a connection portion between the gas-phase reflux pipe 81 and the main supply pipe 41, and the oxidant gas switching valve 83 is connected to the oxidant gas flow path to the mixer 2 in accordance with a control signal from the ECU 9. The connection destination is selectively switched between the oxidizing gas supply device 4 and the gas phase reflux device 8. That is, when the mixer 2 and the oxidizing gas supply device 4 are connected by the oxidizing gas switching valve 83, a new oxidizing gas can be supplied from the oxidizing gas supply device 4 to the mixer 2. And the gas-phase reflux apparatus 8 can be connected to the mixer 2 from the gas-phase reflux apparatus 8.

  The ECU 9 includes an I / O interface for A / D converting sensor detection signals, a RAM and ROM for storing various data and various programs, a CPU for executing various programs, and an oxidizing gas supply in a manner determined under this process. The microcomputer is composed of a drive circuit for driving various devices constituting the device 4, the unreformed fuel supply device 5, the main catalyst supply device 6, the reformed fuel circulation device 7, the gas-phase recirculation device 8, and the like. . Here, the programs executed in the ECU 9 include a new oxidizing gas supply amount by the oxidizing gas supply device 4, an unreformed fuel supply amount by the unreformed fuel supply device 5, and a main catalyst supply amount by the main catalyst supply device 6. A program for controlling the reformed fuel supply amount by the reformed fuel circulation device 7 and the recirculated oxidizing gas supply amount by the gas phase recirculation device 8 (see the program of FIG. And a program for driving the cooling water pump in accordance with the timing of reforming the air-fuel mixture in the reforming reactor 3.

  FIG. 3 is a flowchart showing a procedure for supplying oxidizing gas, fuel, and the like to the mixer using an oxidizing gas supply device, a gas phase reflux device, and the like. The process of FIG. 3 is executed at predetermined intervals in the ECU while the ignition switch is turned on.

  First, in S1, the ECU determines whether fuel reforming by the fuel reforming system is completed. Here, whether or not fuel reforming is completed is determined based on whether or not reformed fuel higher than the target octane number and larger than the target remaining amount is stored in the reformed fuel tank, for example. Here, the remaining amount of the reformed fuel in the reformed fuel tank can be obtained using the output of the level sensor. As a method of estimating the octane number of the reformed fuel, a method of estimating the octane number based on the timing at which occurrence of knocking is detected when the ratio of the unreformed fuel and the reformed fuel of the fuel supplied to the engine is changed. Alternatively, a known estimation method such as a method of estimating the octane number based on the value of the feedback correction coefficient in the feedback control using the air-fuel ratio sensor is used.

  If the determination in S1 is NO, the ECU supplies the mixture to the reforming reactor by supplying oxidizing gas, unreformed fuel, main catalyst, and reacted reformed fuel to the mixer. A reforming operation is performed in which the fuel is supplied and reformed in the reforming reactor (refer to S2 and thereafter). In S2, the ECU controls the unreformed fuel supply amount, the main catalyst supply amount, and the reformed fuel supply amount to have predetermined ratios, and the mixer has reacted with the unreformed fuel and the main catalyst. Of reformed fuel. More specifically, the ECU turns on the feed pump and opens the fuel supply valve, turns on the catalyst metering pump, sets the control valve on the supply side, and turns on the circulation pump. In addition, as described below, the reforming reactor is supplied with the unreformed fuel and the main catalyst by supplying the oxidizing gas to the mixer using the oxidizing gas supply device and the gas phase reflux device. An air-fuel mixture obtained by mixing quality fuel and oxidizing gas is supplied.

  Next, a specific control procedure for supplying the oxidizing gas to the mixer using the oxidizing gas supply device and the gas phase reflux device will be described. When the oxidizing gas is supplied using the oxidizing gas supply device 4 as described above, the reforming reactor is supplied with a new oxidizing gas whose oxidizing power is enhanced by the oxidizing gas processing device. Although there is an effect that the quality reaction rate can be improved, the fuel vapor generated in the reforming operation must be processed by the second steam processing device. On the other hand, when refluxing oxidizing gas is supplied to the mixer using a gas-phase reflux apparatus, only the unreacted oxygen is supplied to the reforming reactor, so the effect of improving the reforming reaction rate in the reforming reactor is Although it is low, the processing load of the fuel vapor in the second steam processing apparatus can be reduced. Therefore, the ECU switches the oxidizing gas switching valve in accordance with the operating state of the engine, thereby providing a new oxidizing gas supply amount from the oxidizing gas supply device to the mixer and a reflux oxidizing gas supply amount from the gas phase reflux device to the mixer. To control.

  More specifically, in S3, the ECU determines whether the engine is stopped due to idling stop. When the determination in S3 is NO, the flow path switching valve of the second steam processing apparatus is set on the upstream flow path side or the downstream flow path side as described above, and the fuel vapor can be processed by the second steam processing apparatus. In this case, the ECU sets the oxidant gas switching valve to the oxidant gas supply device side (see S4), further reduces the supply amount of the recirculated oxidant gas from the vapor phase recirculation device to 0, and performs a new oxidation from the oxidant gas supply device. Gas is supplied (see S5). Thereby, while improving the reforming reaction rate in the reforming reactor, the fuel vapor generated thereby can be appropriately processed by the second steam processing apparatus.

  When the determination in S3 is YES, the flow path switching valve of the second steam processing apparatus is set to the shut-off side as described above, and the second steam processing apparatus cannot sufficiently process the fuel vapor. In this case, the ECU sets the oxidizing gas switching valve on the gas-phase reflux device side (see S6), and increases the amount of refluxing oxidizing gas supplied from the gas-phase reflux device to the mixer more than when the engine is operating. At the same time, the supply amount of the new oxidizing gas from the oxidizing gas supply device to the mixer is set to 0 (see S7), so that the fuel vapor in the second steam processing device is maintained while continuing the reforming operation in the reforming reactor. The processing burden can be reduced.

  Further, when the determination of S1 is YES, that is, when reformed fuel that is higher than the target octane number and larger than the target remaining amount can be acquired in the reformed fuel tank by performing the reforming operation of S2 to S7. The ECU stops the supply of unreformed fuel, main catalyst, reformed fuel, and oxidizing gas to the mixer, and stops the reforming operation in the reforming reactor (see S8).

Although one embodiment of the present invention has been described above, the present invention is not limited to this.
For example, in the above embodiment, the case where the main catalyst is supplied to the mixer together with the unreformed fuel has been described, but the present invention is not limited to this. For example, the main catalyst may be supported on a particulate material or a porous material filled in the reaction tube of the reforming reactor, like the promoter.

  Further, in the above embodiment, when supplying the oxidizing gas, the oxidizing gas switching valve is controlled according to the operating state of the engine, and either the new oxidizing gas from the oxidizing gas supply device or the refluxing oxidizing gas from the gas phase reflux device is selected. (Refer to S3 to S7 in FIG. 3), the present invention is not limited to this. For example, the ratio of the recirculated oxidant gas supply amount to the total oxidant gas supply amount, which is the sum of the new oxidant gas supply amount and the recirculated oxidant gas supply amount, may be continuously changed according to the operating state of the engine. In this case, when the engine is stopped, it is preferable to increase the ratio of the recirculated oxidizing gas supply amount to the total oxidizing gas supply amount as compared with the case where the engine is operating.

DESCRIPTION OF SYMBOLS 1 ... Fuel reforming system 2 ... Mixer 3 ... Reforming reactor 4 ... Oxidizing gas supply device 7 ... Reformed fuel circulation device 73 ... Gas-liquid separator 74 ... Condenser 78 ... Second steam processing device (steam processing device) )
8 ... Gas-phase reflux device 9 ... ECU (control device)
E ... Engine (Internal combustion engine)
E1 ... Intake passage

Claims (5)

A fuel reforming system for reforming a hydrocarbon-based fuel with oxygen to produce a reformed fuel containing alcohol,
A mixer for producing a mixture of oxidizing gas and fuel;
A reforming reactor in which a reforming reaction proceeds under the action of a reforming catalyst and a reformed fuel is discharged from an outlet when an air-fuel mixture is supplied from the mixer;
An oxidizing gas supply device that supplies the mixing gas with the oxidizing gas that has not passed through the reforming reactor;
A gas-liquid separator that separates the reformed fuel of the gas-liquid mixture discharged from the outlet into a gas phase and a condensed phase;
A fuel reforming system comprising: a gas phase recirculation device that supplies at least a part of the gas phase reformed fuel separated by the gas-liquid separator to the mixer as a reflux oxidizing gas. A condenser for condensing the reformed fuel discharged from the gas-liquid separator;
2. The fuel reforming system according to claim 1, further comprising: a steam processing device that supplies a gas-phase reformed fuel that cannot be condensed by the condenser into an intake passage of the internal combustion engine.   A control device for controlling an oxidizing gas supply amount from the oxidizing gas supply device to the mixer and a reflux oxidizing gas supply amount from the gas-phase reflux device to the mixer according to an operating state of the internal combustion engine; The fuel reforming system according to claim 2, further comprising:   4. The fuel according to claim 3, wherein the control device increases the supply amount of the recirculated oxidizing gas when the internal combustion engine is stopped than when the internal combustion engine is operating. Reforming system.   When the internal combustion engine is stopped, the control device provides a total oxidizing gas supply amount that combines the oxidizing gas supply amount and the reflux oxidizing gas supply amount, compared to when the internal combustion engine is operating. 5. The fuel reforming system according to claim 3, wherein the ratio of the supply amount of the refluxing oxidant gas is increased.

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