JP2008298000A - Fuel reforming system and fuel reforming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve fuel economy, increase output and make exhaust gas components clean by improving combustion efficiency of an internal combustion engine. <P>SOLUTION: Exothermic reaction of ethanol fuel and air supplied from an air supply device 46 is performed on a fuel reforming device 24 during start of the internal combustion engine 12, and heat (reformed gas) generated by the exothermal reaction is led out to an exhaust side three-way catalyst 20 via a three-way change over valve 32 and a second circulation passage 34 to warm up the three-way catalyst 20. Endothermic reaction of ethanol fuel, steam and heat in exhaust gas circulated by an exhaust gas circulation passage 28 is performed on the fuel reforming device 24 during normal travel, and reformed gas containing hydrogen formed by the endothermic reaction is sent to the internal combustion engine 12 along a first recirculation passage 26 under a change over action of the three-way change over valve 32. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel reforming system and a fuel that can achieve fuel efficiency improvement, high output, and exhaust gas cleaning by improving fuel efficiency by performing a reforming reaction using a biomass fuel. The present invention relates to a reforming method.

Biomass-based automobile fuels are made from biomass that can be abundant resources as plants such as sugarcane, corn, and non-standard wheat, and have been introduced as alternative fuels in the background of the past oil crisis. In recent years, biomass-based fuels (hereinafter also referred to as bio-based fuels), which are renewable energies, have an effect of suppressing the amount of carbon dioxide (CO ₂ ) generated, and biomass waste is effectively used. Attention has been focused on as one of the important issues for global warming countermeasures.

In particular, in automobile fuels, as a substitute for oxygen-containing fuels (eg, methyl tertiary butyl ether: MTBE) that can be expected to have an effect as an octane number improver, ethanol-mixed gasoline in which biomass-derived ethanol is mixed with gasoline has become widespread. (For example, refer to Patent Document 1).
JP 2004-285346 A (paragraphs 0009 to 0111)

However, regarding the fuel consumption of ethanol fuel-based automobiles, there is a problem that the fuel consumption is lowered according to the amount of mixing because the calorific value of ethanol itself is smaller than that of gasoline.
In addition, regarding the exhaust gas at the start of the ethanol fuel vehicle, the ignition timing cannot be retarded (retarded) due to the ethanol fuel characteristic that the calorific value of ethanol itself is smaller than that of gasoline. There is another problem that the exhaust gas component cannot be suitably purified immediately after starting.

  That is, when gasoline is used as a fuel for automobiles, for example, the three-way catalyst is quickly heated by heating means such as a heater, the exhaust gas temperature is quickly raised, and the ignition timing is retarded to exhaust the three-way catalyst. While it is possible to purify gas components, when ethanol is used as automobile fuel, the amount of heat generated by the ethanol is small compared to gasoline. Immediately after that, another problem arises that the exhaust gas component cannot be purified appropriately.

  The present invention has been made in view of the above problems, and a general object of the present invention is not only to use a biomass fuel such as ethanol or ethanol-mixed gasoline as a fuel for an internal combustion engine, but also an endothermic reaction. It is possible to achieve improved fuel efficiency and higher output by regenerating exhaust energy and improving the combustion efficiency of the internal combustion engine by reforming using hydrogen, converting it to hydrogen gas containing hydrogen and supplying it to the internal combustion engine A fuel reforming system and a fuel reforming method are provided.

  In addition, the main object of the present invention is to use the biomass fuel and raise the temperature of the three-way catalyst by warming up using an exothermic reaction at the start of the internal combustion engine, thereby cleaning the exhaust gas components at the start. It is an object to provide a fuel reforming system and a fuel reforming method capable of achieving the above.

  Furthermore, another object of the present invention is to provide a warm-up using the biomass fuel, performing reforming utilizing an endothermic reaction, converting it into hydrogen gas containing hydrogen and supplying it to an internal combustion engine, and utilizing an exothermic reaction. A fuel reforming system and a fuel reforming method capable of achieving regeneration of exhaust energy, improving fuel efficiency by improving the combustion efficiency of an internal combustion engine, achieving higher output and cleaner exhaust gas components at start-up It is to provide.

To achieve the above object, the present invention provides a fuel reforming means provided in a circulation passage for circulating exhaust gas exhausted from an internal combustion engine to the intake side of the internal combustion engine, and having a reforming catalyst;
Biofuel supply means for supplying biomass fuel to the fuel reforming means;
An air supply means connected to the circulation passage for supplying air to the fuel reforming means;
The passage is switched so that the reformed gas provided in the circulation passage and fed from the fuel reforming means is led out to the exhaust side of the internal combustion engine or to the circulation passage on the internal combustion engine side. Switching means;
It is characterized by providing.

  According to the present invention, at the start of the internal combustion engine, the fuel reforming means performs an exothermic reaction between the air supplied from the air supply means and the biomass fuel, and under the switching action of the switching means, Heat generated by the exothermic reaction is derived to the exhaust side of the internal combustion engine. In this case, the three-way catalyst disposed on the exhaust side of the internal combustion engine is warmed up by the heat generated by the exothermic reaction, so that the exhaust gas component can be cleaned quickly.

  On the other hand, according to the present invention, during normal operation, the fuel reforming means performs an endothermic reaction between the heat in the exhaust gas circulated through the circulation passage, the water vapor, and the biomass fuel, and the switching action of the switching means. Below, the reformed gas containing hydrogen generated by the endothermic reaction is fed to the internal combustion engine along a circulation path. As a result, in the internal combustion engine, by introducing the reformed gas containing hydrogen, hydrogen energy increases, and fuel improvement (thermal efficiency improvement) and high output can be achieved by improving the fuel with hydrogen.

  Further, in the present invention, it is preferable to provide a gas circulation blocking means for blocking the circulation of the exhaust gas to the circulation passage when an exothermic reaction is performed at the start of the internal combustion engine. By the gas circulation preventing means, it is possible to ensure a stable supply of air from the air supply means to the fuel reforming means.

  Further, in the present invention, the switching mechanism is controlled when an exothermic reaction utilizing air is performed in the fuel reforming means and when an endothermic reaction is performed utilizing the heat of the exhaust gas circulating along the circulation passage and water vapor. By providing the control means, the flow path of the reformed gas can be easily switched.

The present invention provides a fuel reforming means having a reforming catalyst in a circulation passage for circulating exhaust gas exhausted from an internal combustion engine to the intake side of the internal combustion engine, and biomass fuel to the fuel reforming means. Biofuel supply means for supplying, respectively,
At the time of starting the internal combustion engine, an exothermic reaction is performed between the air and the biomass fuel on the fuel reforming means. On the other hand, during normal operation, heat and water vapor in the exhaust gas circulated along the circulation path An endothermic reaction with the biomass fuel is performed on the fuel reforming means. In this case, an exothermic reaction due to oxidation of the biomass fuel is performed at the start of the internal combustion engine, and the reforming catalyst is baked, and then used for an endothermic reaction during normal operation.

In this case, according to the present invention, the fuel reforming means having the reforming catalyst is provided in the circulation passage for circulating the exhaust gas exhausted from the internal combustion engine to the intake side of the internal combustion engine. After the endothermic reaction on the reforming means, the temperature of the exhaust gas can be lowered and the cooler effect can be exhibited.
According to the present invention, the reformed gas containing hydrogen is supplied to the internal combustion engine by the endothermic reaction, thereby preventing abnormal combustion in the internal combustion engine and suppressing the occurrence of knocking. The load on the pistons and cylinders constituting the internal combustion engine can be reduced and the durability can be improved.
Further, in the present invention, since the exothermic reaction and the endothermic reaction are respectively exhibited by the single fuel reforming means provided in the circulation passage, the entire fuel reforming system can be reduced in size and the manufacturing cost. Can be achieved.

  In the present invention, the raw material used as the reformed fuel is a biomass-based fuel such as ethanol or ethanol-mixed gasoline (ethanol mixing ratio of 3 to 99% can be used), and reformed by using the biomass-based fuel. The reaction can be easily generated. Examples of the biomass fuel include hydrocarbons such as ethanol, gasoline, diesel fuel, natural gas, hydrocarbon gas, and biodiesel. Examples of the hydrocarbons include alkanes, alkenes, alkynes, aromatic compounds, alcohols, aldehydes and the like.

  Examples of the modifier include at least one selected from air, oxygen, oxygen-enriched air, nitrogen-enriched air, water, and carbon dioxide. In addition to pure water, rain water, tap water, primary treated waste water, or the like can be used as water. Note that the oxygen-enriched air used as the oxidant can be implemented in a concentration range where oxygen is 25 to less than 100%. In general, it is desirable that the oxygen-enriched air has an oxygen concentration of 35 to 45%. This is because as the oxygen concentration increases, the load on the gas separation membrane increases and the total energy efficiency decreases.

  In the present invention, the exhaust gas components discharged from the internal combustion engine include nitrogen, oxygen, carbon monoxide, carbon dioxide, water, nitric oxide, nitrogen dioxide, nitric oxide, and hydrocarbons. . Examples of the hydrocarbons include alkanes, alkenes, alkynes, aromatics, polycyclic aromatics, alcohols, aldehydes and the like.

  In the present invention, the reforming reaction is performed by a method using at least one selected from a catalyst, a low temperature plasma, and a low temperature plasma-catalyst composite system. Here, the “catalyst” means a catalyst such as a metal oxide system, a zeolite system, a metal support system, or a noble metal support system. In addition, “low temperature plasma” means plasma in which electrons, ions, and neutral molecules are not in a thermal equilibrium state. In the low temperature plasma reactor using this low temperature plasma, although the electron temperature reaches 8000 ° C. to 80000 ° C., the gas temperature has an advantage that it can be suppressed to substantially room temperature.

  In the present invention, the biomass fuel reforming reaction is at least one of a complete oxidation method, a partial oxidation method, a steam reforming method, and an autothermal reforming method in which the partial oxidation method and the steam reforming method are combined. One reaction may be used.

  In the present invention, any conventionally known fuel reforming means can be used and is not particularly limited. Examples of such a reaction apparatus include a fixed bed flow reactor and a batch reactor. Also, any conventionally known apparatus for generating low-temperature plasma can be used and is not particularly limited. As such a low-temperature plasma apparatus, for example, a pulse corona type, a silent discharge type, a packed bed type, or the like can be used.

  In the present invention, the fuel reforming reaction can be carried out in a temperature range from room temperature to about 1200 ° C. In the fuel reforming reaction, the hydrogen concentration in the reformed gas can be adjusted by the vapor pressure of the product.

  In the present invention, as the fuel reforming means, the fuel may be directly introduced into the reaction apparatus, but may be introduced into the reaction apparatus after being vaporized into a background gas such as air. Although there is no restriction | limiting in particular in reaction pressure, Preferably it is set as a normal pressure of 1 atmosphere.

  In the present invention, the membrane used for gas separation is not particularly limited, and conventionally known membranes can be used. Examples of such a gas separation membrane include a polyimide hollow fiber and a polydimethylsiloxane flat membrane.

  According to the present invention, it is possible to provide a fuel reforming system and a fuel reforming method that can improve fuel efficiency by improving combustion efficiency, increase output, and clean exhaust gas. As a result, a fuel reforming system and a fuel reforming method capable of realizing carbon neutral can be provided.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. FIG. 1 is a schematic block diagram of an automobile system to which a fuel reforming system according to an embodiment of the present invention is applied.

  As shown in FIG. 1, the automobile system 10 includes an internal combustion engine 12 (hereinafter referred to as the engine 12). The engine 12 has a cylinder block (not shown) provided with a combustion chamber, and an intake passage 14 for sucking an air-fuel mixture via an intake valve (not shown) and a combustion chamber via an exhaust valve (not shown). Is connected to an exhaust passage 16 for exhausting the combustion gas generated in (1) to the outside.

  In this embodiment, biomass-based automobile fuel such as ethanol or ethanol-mixed gasoline is used as the fuel. Hereinafter, a case where ethanol is used will be described as an example.

  In the exhaust passage 16, an oxygen sensor 18 that detects the concentration of oxygen contained in the exhaust gas, a three-way catalyst 20 that purifies exhaust gas components contained in the exhaust gas, and a temperature of the three-way catalyst 20 are detected. A first temperature sensor 22 is provided.

  The automobile system 10 includes a fuel reforming device (fuel reforming means) 24, and the fuel reforming device 24 includes a first circulation passage 26 communicating with a predetermined portion of the intake passage 14 adjacent to the engine 12. The engine 12 is connected to the engine 12 through an exhaust circulation passage 28 communicating with a predetermined portion of the exhaust passage 16 adjacent to the engine 12. In this case, the fuel reformer 24, the first circulation passage 26, the engine 12, and the exhaust circulation passage 28 constitute a closed loop (circulation passage). The fuel reformer 24 is provided with a second temperature sensor 30 for detecting the catalyst temperature (the temperature of the three-way catalyst 20 in the embodiment described later is detected). The first circulation passage 26 will be described as appropriate by dividing it into a first circulation passage 26a on the fuel reformer side and a first circulation passage 26b on the engine side with a three-way switching valve to be described later in between.

  Further, the automobile system 10 is provided with a three-way switching valve (switching means) 32 in the middle of the first circulation passage 26, and the secondary side (output side) of the three-way switching valve 32 is connected to the fuel reformer side. A second circulation passage 34 that connects the first circulation passage 26a and the exhaust circulation passage 28 is connected.

  That is, the three-way switching valve 32 is composed of, for example, a three-port solenoid valve or the like, and an inlet port 36a provided in a valve body (not shown) is connected to the first circulation passage 26a on the fuel reformer side and provided in the valve body. The first outlet port 36b thus connected is connected to the first circulation passage 26b on the engine side, and the second outlet port 36c provided on the valve body is connected to the second circulation passage 34, respectively.

  In this case, an inlet port 36a (first circulation passage 26a), a first outlet port 36b (first circulation passage 26b), and a second outlet port 36c (in accordance with a control signal (ON / OFF signal) output from the ECU described later. A communication state between the second circulation passage 34) and the second circulation passage 34) can be switched through a valve body (not shown).

  The exhaust circulation passage 28 has a valve body (not shown) that opens and closes the exhaust circulation passage 28, and an exhaust gas recirculation valve (switching between a valve opening state and a valve closing state is controlled by a control signal introduced from the ECU 40 ( Gas circulation prevention means) 42 and an air supply device (air supply means) 46 (for example, a compressor) for supplying air to the fuel reformer 24 via the communication passage 44 are provided.

  Therefore, the three-way switching valve 32 supplies the reformed gas containing hydrogen supplied from the fuel reformer 24 to the engine 12 via the first circulation passages 26a and 26b, and the fuel reforming. The second switching position for supplying the reformed gas containing air supplied from the gas purification device 24 to the three-way catalyst 20 via the second circulation passage 34, the exhaust circulation passage 28, and the exhaust passage 16 is provided to be switchable. .

  The engine 12 is composed of, for example, a 4-cylinder engine that can be operated with gasoline or a fuel mixture of gasoline and alcohol. A throttle valve 50 is provided upstream of the intake passage 14 of the engine 12, and a throttle valve opening sensor 52 that detects the throttle valve opening is attached to the throttle valve 50. A detection signal corresponding to the throttle valve opening detected by the throttle valve opening sensor 52 is sent to an ECU (control means) 40 (Electronic Control Unit) and used for controlling the fuel injection amount to the engine 12.

  The first fuel injection valve 54 a is provided in each cylinder in the middle of the intake passage 14 and slightly upstream of the intake valve (not shown) between the engine 12 and the throttle valve 50. Furthermore, a second fuel injection valve (biofuel supply means) 54b for supplying fuel to the fuel reformer 24 is provided. The first fuel injection valve 54a and the second fuel injection valve 54b are connected to a fuel tank 58 through a fuel supply passage 56, respectively. The second fuel injection valve 54 b is connected to the exhaust circulation passage 28 via the fuel reformer 24. The first fuel injection valve 54a and the second fuel injection valve 54b may be configured identically in order to share parts.

  In this case, the first fuel injection valve 54a and the second fuel injection valve 54b are electrically connected to the ECU 40, respectively, and the valve opening time is controlled based on a control signal output from the ECU 40.

  The fuel reformer 24 uses exhaust gas, water, oxygen in the air, or the like as an oxidant, reacts with the fuel to generate hydrogen (endothermic reaction), and reacts with the fuel at the time of startup to generate heat. (Exothermic reaction) and the function of warming the three-way catalyst 20 by the heat. The utilization ratio of the oxidant is controlled by the ECU 40 so as to be optimized in accordance with the fuel component, the temperature of the combustion exhaust gas, the supply amount of hydrogen, the supply amount of heat, the supply timing, and the like.

  In addition, the fuel reformer 24 is preferably at least one reaction selected from an oxidation reaction, a partial oxidation method, a steam reforming method, and an autothermal reforming method combining these with a reforming catalyst. . By using such a reforming method, the reaction is accelerated and a mixed gas of hydrogen, carbon dioxide, water, and carbon monoxide is generated. As the fuel reformer 24, all conventionally known devices can be used. For example, a flow reactor, a batch reactor, etc. (not shown) are used.

  The ethanol reforming reaction formula using each reforming method is shown in FIGS. 5A to 5D for reference. Here, the partial oxidation method refers to a reaction in which hydrocarbons are reformed with oxygen to generate hydrogen and carbon dioxide. The steam reforming method refers to a reaction in which hydrocarbons are reformed with steam to generate hydrogen and carbon dioxide. The autothermal method is a combination of a steam reforming method and a partial oxidation method, and both oxygen and steam act as oxidizing agents. Specifically, oxygen in the air promotes a partial oxidation reaction and a steam reforming reaction, and steam promotes a steam reforming reaction. For this reason, when autothermal reforming of automobile fuel, it is important to control the amount of oxygen and water vapor present during the reforming reaction.

  The automobile system 10 to which the fuel reforming system according to the present embodiment is applied is basically configured as described above. Next, the function and effect will be described.

First, the starting time of the engine 12 will be described.
When starting the engine 12, the ECU 40 derives an urging signal to the air supply device 46 to drive the air supply device 46, and supplies air (oxygen) to the fuel reformer 24 via the communication path 44. Supply. At the same time, the ECU 40 derives a control signal to a solenoid unit (not shown) of the three-way switching valve 32 to switch the valve body (not shown) to the second switching position, and the first circulation passage 26a and the second circulation on the fuel reformer side. The passage 34 is communicated (see the solid line in the three-way switching valve 32 in FIG. 1). Further, the ECU 40 derives a control signal to the exhaust gas recirculation valve 42 and shuts off the exhaust gas recirculation at the time of start to the fuel reformer side with the exhaust gas recirculation valve 42 as the closed position.

  Accordingly, an ignition switch (not shown) is energized, and the air supplied from the air supply device 46 is in the starting state of the engine 12 in which the exhaust gas of the engine 12 flows toward the three-way catalyst side through the exhaust passage 16. While being supplied into the fuel reformer 24, ethanol is supplied from the fuel tank 58 through the second fuel injection valve 54 b into the fuel reformer 24. Therefore, air (oxygen) and fuel (ethanol) react with each other through a catalyst (not shown) provided in the fuel reformer 24 to generate heat, and the reformed gas having the generated heat quantity is the first gas. The three-way catalyst 20 is introduced into the three-way catalyst 20 through the one-circulation passage 26 a, the three-way switching valve 32, the second circulation passage 34, a part of the engine-side exhaust gas circulation passage 28, and the exhaust passage 16. The catalyst 20 can be suitably warmed up. Note that the solid line in FIG. 4 shows a simplified exothermic reaction when the engine is started.

  In other words, the fuel reformer 24 uses the air (oxygen) supplied from the air supply device 46 as an oxidant and reacts with the fuel (ethanol) discharged from the second fuel injection valve 54b to generate heat. By conducting the exothermic reaction and introducing the reformed gas having the generated heat into the three-way catalyst 20, the temperature characteristics of the three-way catalyst 20 at the time of starting the engine can be rapidly increased. As a result, the three-way catalyst 20 functions smoothly by the high temperature rise of the three-way catalyst 20 to purify the exhaust gas component at the time of starting the engine, thereby achieving early cleanup.

  After the engine 12 has been started for a predetermined time, the ECU 40 derives a deactivation signal to the air supply device 46 and supplies air (oxygen) from the air supply device 46 to the fuel reforming device 24. And a control signal is derived to the three-way switching valve 32 to switch the valve body (not shown) to the first switching position (see the broken line in the three-way switching valve in FIG. 1). The 1 circulation path 26a and the 1st circulation path 26b by the side of an engine are connected. At the same time, the ECU 40 derives a control signal to the exhaust gas recirculation valve 42 and switches the exhaust gas recirculation valve 42 to the open position so that the exhaust gas can recirculate to the fuel reformer side.

  In such a normal running state (during steady operation) after the engine 12 has been started for a predetermined time, the exhaust gas of the engine 12 is introduced into the fuel reformer 24 via the exhaust circulation passage 28 and the fuel reforming is performed. In the gas generator 24, hydrogen (water vapor) contained in the exhaust gas, heat (heat amount) held by the exhaust gas, and fuel (ethanol) discharged by the second fuel injection valve 54b are reacted to generate hydrogen. An endothermic reaction is carried out. Hydrogen generated by such an endothermic reaction is introduced into the engine 12 via the three-way switching valve 32, and by increasing the hydrogen energy, the exhaust energy is regenerated, the fuel efficiency is improved and the output is increased by improving the combustion efficiency of the internal combustion engine. can do. The broken line in FIG. 4 shows the endothermic reaction in a simplified manner.

In the normal running state, the fuel reformer 24, the first circulation passage 26, the engine 12, and the exhaust circulation passage 28 form a closed loop, and the reformed gas containing hydrogen generated by the intake reaction described above is closed loop. Are always generated continuously.
As described above, the present embodiment has been described based on the internal combustion engine 12 mounted on the automobile system 10, but the present invention is not limited to this. For example, the internal combustion engine such as a ship, a cultivator, or a generator (not shown) may be used. Of course, it can be applied.

Next, the present invention will be further described in detail based on examples in which the effects of the present invention have been confirmed. In addition, this invention is not limited to this Example. In the fuel reformer, Rh / Al ₂ O ₃ was used as the catalyst, and ethanol was used as the biofuel.

First, a method for adjusting the catalyst will be described.
[Adjustment of catalyst γAl ₂ O ₃ ]
About 100 g of the prepared γAl ₂ O ₃ (AKP-G015 manufactured by Sumitomo Chemical Co., Ltd.) was suspended in 300 mL of ultrapure water in a 1000 mL beaker. A Teflon (registered trademark) stirrer piece was put into the obtained suspension solution, and gently stirred at room temperature for several minutes with a magnetic stirrer with a hot plate. After stirring, water was removed and the above operation was repeated three times. Thereafter, the obtained γAl ₂ O ₃ was covered so as not to enter dust, and vacuum-dried at 80 ° C. overnight to distill off water. After drying, it was transferred to a storage container and stored in a desiccator until use.

[Adjustment of fuel reforming catalyst Rh / Al ₂ O ₃ (impregnation method)]
25 g of dried γAl ₂ O ₃ powder was weighed. On the other hand, rhodium nitrate [Rh (NO ₃ ) ₃ ] was weighed so that the mass fraction of rhodium (Rh) metal was 5%.
(Catalyst support)
In a beaker having a volume of 1000 mL, rhodium nitrate [Rh (NO ₃ ) ₃ ] and 350 mL of ultrapure water were added, stirred and heated, and set to 60 ° C. Into the 1000 mL beaker, γAl ₂ O ₃ powder was slowly added little by little so that the temperature of 60 ° C. could be maintained. After adding γAl ₂ O ₃ powder, the mixture was stirred at 60 ° C. for 1 hour. Thereafter, water was distilled off from the slurry, and the slurry was placed in an oven at 100 ° C. for 12 hours to dry. The dried catalyst was placed in an electric furnace at 600 ° C. for 4 hours and calcined.

[Adjustment of catalyst Ag / Al ₂ O ₃ (impregnation method)]
25 g of dried γAl ₂ O ₃ powder was weighed. On the other hand, silver nitrate [AgNO ₃ ] was weighed so that the mass fraction of silver (Ag) metal was 2%.
(Catalyst support)
Silver nitrate [AgNO ₃ ] and 350 mL of ultrapure water were placed in a 1000 mL beaker and stirred and heated to set the temperature at 60 ° C. Into the 1000 mL beaker, γAl ₂ O ₃ powder was slowly added little by little so that the temperature of 60 ° C. could be maintained. After adding γAl ₂ O ₃ powder, the mixture was stirred at 60 ° C. for 1 hour. Thereafter, water was distilled off from the slurry, and the slurry was placed in an oven at 100 ° C. for 12 hours to dry. The dried catalyst was placed in an electric furnace at 600 ° C. for 4 hours and calcined.

[Reforming reaction conditions for biofuels]
In this example, the catalyst Rh / Al ₂ O ₃ was used for the reforming reaction. In addition, a partial oxidation reaction was performed as biofuel reforming. Specific reaction conditions were as follows.

The GHSV for the catalyst (Gas hourly space velocity = reaction gas space velocity per hour) was carried out in the range of 1000 to 100,000 h ⁻¹ . Air was used as the background gas, and the mass ratio A / F ratio of air (Air) to fuel (Fuel) was in the range of 1-30. The temperature of the reforming reaction was performed within a range of 250 ° C to 1000 ° C. The quantitative analysis of the organic compound was performed using GC (GL Science GC-390B, Unipack S) equipped with a FID (flame ionization detector) as a detector. Moreover, quantitative analysis of hydrogen was performed using GC (Shimadzu GC-390B, MS-5A) equipped with a TCD (thermal conductivity detector) as a detector.

<Comparison study on fuel consumption>
As a comparative example, a general FFV (Flexible Fuel Vehicle) without the fuel reformer 24 is used, and the fuel reformer 24 having the structure of the automobile system 10 shown in FIG. FIG. 2 shows an experimental result of comparing fuel consumption using FFV (Flexible Fuel Vehicle). That is, this experiment was conducted to examine how the presence or absence of a fuel reforming system affects fuel consumption. The FFV according to the comparative example and the FFV according to the present embodiment have the same structure, fuel, operating conditions, and the like of the FFV used except that the presence or absence of the fuel reformer 24 is different.

  As can be seen from FIG. 2, in the comparative example, the fuel consumption decreases as the blend ratio (mixing ratio) of ethanol increases. This is because the calorific value of ethanol is smaller than that of gasoline. In contrast, in this example as well, the fuel efficiency decreased with an increase in the ethanol blending ratio. However, in this example, the fuel efficiency improved by about 15% of the comparative example over the entire range of the ethanol blending ratio. It was recognized that

  It is determined that the fuel efficiency has been improved by increasing the amount of hydrogen energy by, for example, about 20% by the endothermic reaction of the fuel and by improving the combustion with hydrogen. Further, when the blend ratio of ethanol was about 70% or less, the fuel consumption exceeded that of the gasoline vehicle when the fuel consumption of the gasoline vehicle was 100% (reference value). From these experimental results, in this embodiment, it can be confirmed that the use of the fuel reforming system improves the fuel consumption and is useful compared to the comparative example not using the fuel reforming system. did it.

<Comparison study on three-way catalyst temperature>
FIG. 3 shows the experimental results comparing the temperature change of the three-way catalyst 20 with respect to time using the same FFV as in the comparative example regarding fuel efficiency and this example. The temperature of the three-way catalyst 20 was detected by a first temperature sensor 22 shown in FIG.

  In both the comparative example and the present example, the temperature of the three-way catalyst 20 increases with the passage of time. However, in the comparative example, it took about 310 seconds for the temperature of the three-way catalyst 20 to reach about 350 ° C. or higher, whereas in this example, the time required to reach 350 ° C. or higher was about In about 30 seconds, it was able to be reached in a time that is about one tenth of that of the comparative example (see FIG. 3).

  From this, in this example, it was suggested that the temperature of the three-way catalyst 20 can be increased by warming up due to the exothermic action, and that the exhaust gas can be quickly cleaned at the time of starting (of the three-way catalyst 20). This is because it is presumed that the exhaust component purifying effect is suitably exhibited by warm-up). As a result, in this embodiment, the use of the fuel reforming system makes it possible to increase the temperature of the three-way catalyst 20 at a higher speed than in the comparative example not using the fuel reforming system, and it is confirmed that there is utility. We were able to.

1 is a schematic configuration block diagram of an automobile system to which a fuel reforming system according to an embodiment of the present invention is applied. It is a characteristic view which shows the relationship between the ethanol mixing rate and fuel consumption concerning a present Example and a comparative example. It is a temperature characteristic figure of the three way catalyst concerning this example and a comparative example. FIG. 2 is a block configuration diagram for explaining an exothermic reaction and an endothermic reaction of the fuel reforming system in the automobile system shown in FIG. 1. (A)-(d) is explanatory drawing which showed the ethanol reforming reaction type | formula using each reforming method.

Explanation of symbols

12 Internal combustion engine
Reference Signs List 14 intake passage 16 exhaust passage 20 three-way catalyst 24 fuel reformer 26 (26a, 26b) first circulation passage 28 exhaust circulation passage 32 three-way switching valve (switching means)
34 Second circulation passage 40 ECU (control means)
42 Exhaust gas recirculation valve (gas circulation prevention means)
46 Air supply device (air supply means)
54b Fuel injection valve (biofuel supply means)

Claims (7)

Fuel reforming means provided in a circulation passage for circulating exhaust gas exhausted from the internal combustion engine to the intake side of the internal combustion engine, and having a reforming catalyst;
Biofuel supply means for supplying biomass fuel to the fuel reforming means;
An air supply means connected to the circulation passage for supplying air to the fuel reforming means;
The passage is switched so that the reformed gas provided in the circulation passage and fed from the fuel reforming means is led out to the exhaust side of the internal combustion engine or to the circulation passage on the internal combustion engine side. Switching means;
A fuel reforming system comprising: The fuel reforming system according to claim 1, wherein
At the start of the internal combustion engine, an exothermic reaction is performed on the fuel reforming unit between the air supplied from the air supply unit and the biomass fuel, and the heat generated by the exothermic reaction is generated by the internal combustion engine. The fuel reforming is conducted to the three-way catalyst provided on the exhaust side, and on the other hand, during normal operation, the endothermic reaction is performed between the heat in the exhaust gas circulated by the circulation passage, water vapor, and the biomass fuel. The fuel reforming system is characterized in that a control means for controlling the switching means is provided so that the reformed gas containing hydrogen is supplied to the internal combustion engine through the circulation passage. The fuel reforming system according to claim 2, wherein
A fuel reforming system, characterized in that, when performing the exothermic reaction, a gas circulation preventing means is provided for preventing the exhaust gas exhausted from the internal combustion engine from circulating toward the fuel reforming means side. A fuel reforming means having a reforming catalyst in a circulation passage for circulating exhaust gas exhausted from the internal combustion engine to the intake side of the internal combustion engine, and a biofuel supply for supplying biomass fuel to the fuel reforming means Means are provided,
At the time of starting the internal combustion engine, an exothermic reaction is performed between the air and the biomass fuel on the fuel reforming means. On the other hand, during normal operation, heat and water vapor in the exhaust gas circulated along the circulation path An endothermic reaction with the biomass fuel is performed on the fuel reforming means. The fuel reforming method according to claim 4, wherein
The biomass fuel includes ethanol or ethanol-mixed gasoline, and the reforming reaction of the biomass fuel includes at least a complete oxidation method, a partial oxidation method, a steam reforming method, and the partial oxidation method and the steam reforming method. A fuel reforming method comprising any one reaction of an autothermal reforming method in combination with The fuel reforming method according to claim 4 or 5,
The reforming reaction of the biomass fuel is performed in any one of exhaust gas, air, oxygen-enriched air, nitrogen-enriched air, oxygen, nitrogen, and steam atmosphere. . The fuel reforming method according to any one of claims 4 to 6,
A fuel reforming method characterized in that an exothermic reaction due to oxidation of the biomass fuel is performed at the start of the internal combustion engine, and the reforming catalyst is baked and then used for an endothermic reaction during normal operation. .

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