JP2004315318A - Fuel reformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reforming efficiency by securely preventing liquefied fuel from flowing into a reform catalyst. <P>SOLUTION: A fuel reformer 20 for reforming a fuel-air mixture is equipped with a reform reaction part 23 containing the reforming catalyst for reforming the fuel-air mixture, a fuel-trapping chamber 28 for recovering the fuel which is liquefied before being introduced into the reform reaction part 23, a gas-liquid separation fin 29 etc. The fuel-trapping chamber 28 is connected via a connecting pipe L3 having an on-off valve 18 at the midpoint to a by-pass pipe L2 for supplying air to the reform reaction part 23. The fuel trapped into the fuel-trapping chamber 28 is re-supplied into the by-pass pipe L2 via the connecting pipe L3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel reformer for reforming a mixture of fuel and air.
[0002]
[Prior art]
BACKGROUND ART Conventionally, as a fuel reforming apparatus for obtaining a reformed gas to be supplied to a combustion chamber of a vehicle engine, a mixture of a hydrocarbon-based fuel and air is partially oxidized by a reforming catalyst to obtain CO and H 2. _One that generates a reformed gas containing No. ₂ is known (for example, see Patent Document 1). In such a conventional fuel reformer, at the time of startup, fuel is sent from a fuel tank to a fuel vaporizer, and the fuel vaporized by the fuel vaporizer is supplied to the reforming catalyst. Further, in such a conventional fuel reforming apparatus, when the temperature of the reforming catalyst becomes higher than a predetermined temperature, the fuel vaporized using the heat of the reforming catalyst is supplied to the reforming catalyst.
[0003]
[Patent Document 1]
JP-A-3-179121
[Problems to be solved by the invention]
However, in the conventional fuel reforming apparatus described above, especially when the temperature of the reforming catalyst is not sufficiently high, the fuel liquefies before reaching the reforming catalyst, and the liquid fuel flows into the reforming catalyst. It can happen. As described above, when the fuel is liquefied before being introduced into the reforming catalyst, it becomes impossible to stably supply the air-fuel mixture of the uniformly mixed fuel and air to the reforming catalyst. It becomes impossible to obtain a desired reforming efficiency, that is, an amount of reformed gas close to the theoretical value. Also, when liquid fuel flows into the reforming catalyst, the amount of unreformed fuel (unreformed HC) from the reforming device increases, so that unreformed HC and the like in the engine exhaust are reduced to zero. Is difficult to approach.
[0005]
Therefore, an object of the present invention is to provide a fuel reforming apparatus capable of reliably preventing liquefied fuel from flowing into a reforming catalyst and improving reforming efficiency.
[0006]
[Means for Solving the Problems]
A fuel reforming apparatus according to the present invention is a fuel reforming apparatus for reforming an air-fuel mixture of fuel and air, comprising: a reforming reaction section including a reforming catalyst for reforming the air-fuel mixture; And liquefied fuel recovery means for recovering liquefied fuel before being introduced into the section.
[0007]
In this fuel reforming apparatus, for example, even if the fuel is liquefied before being introduced into the reforming reaction section when the temperature of the reforming catalyst is not sufficiently increased, the fuel is liquefied with respect to the reforming reaction section. Inflow of fuel is prevented by the liquefied fuel recovery means. Therefore, in this fuel reforming apparatus, a gas mixture of fuel and air uniformly mixed can be stably supplied to the reforming reaction section, so that the desired reforming efficiency, that is, a reforming amount close to the theoretical value, is achieved. Quality gas can be obtained. Further, in this fuel reforming apparatus, since the liquefied fuel is reliably prevented from flowing into the reforming reaction section, the amount of unreformed fuel (unreformed HC) from the fuel reforming apparatus is extremely reduced. It becomes possible.
[0008]
In this case, it is preferable to further include an air supply path for supplying air to the reforming reaction section, and a connection path connecting the liquefied fuel recovery unit and the air supply path.
[0009]
If such a configuration is adopted, the fuel recovered by the liquefied fuel recovery means can be mixed with the air in the air supply path and re-supplied to the reforming reaction section.
[0010]
Further, it is preferable that the liquefied fuel recovery means can vaporize the recovered fuel by utilizing heat generated in the reforming reaction section. With such a configuration, the recovered fuel can be uniformly mixed with air and re-supplied to the reforming reaction section.
[0011]
Further, the liquefied fuel collecting means may further include an adsorbent capable of adsorbing the liquefied fuel. By employing such a configuration, it is possible to reliably suppress the liquefied fuel from being mixed with the air again.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a fuel reformer according to the present invention will be described in detail with reference to the drawings.
[0013]
FIG. 1 is a schematic configuration diagram showing a vehicle C provided with a fuel reforming device according to the present invention. The vehicle C shown in the figure has an engine (internal combustion engine) 1 as a driving source for traveling. The engine 1 generates power by burning an air-fuel mixture containing a combustion component inside a combustion chamber 3 formed in an engine block 2 and reciprocating a piston 4 in the combustion chamber 3. In this embodiment, the engine 1 is configured as a four-cylinder engine, as can be seen from FIG. 2 (however, FIG. 1 shows only one cylinder).
[0014]
An intake port of each combustion chamber 3 is connected to an intake pipe 5a forming an intake manifold 5, and an exhaust port of each combustion chamber 3 is connected to an exhaust pipe 6a forming an exhaust manifold 6, respectively. An intake valve Vi for opening and closing an intake port and an exhaust valve Ve for opening and closing an exhaust port are provided for each combustion chamber 3 in a cylinder head of the engine 1. Each intake valve Vi and each exhaust valve Ve are opened and closed by, for example, a valve operating mechanism (not shown) having a variable valve timing function. Further, a plurality of spark plugs 7 are arranged on the cylinder head of the engine 1 so as to face the respective combustion chambers 3. The exhaust manifold 6 is connected to a catalyst device (three-way catalyst) not shown.
[0015]
As can be seen from FIGS. 1 and 2, each intake pipe 5a constituting the intake manifold 5 is connected to a surge tank 8, and the intake manifold 5 (each intake pipe 5a) and the surge tank 8 are connected to the engine 1 Configure the intake system. An air supply pipe L1 is connected to the surge tank 8, and the air supply pipe L1 is connected via an air cleaner 9 to an air inlet (not shown). A throttle valve (in the present embodiment, an electronic throttle) 10 is incorporated in the middle of the air supply pipe L1 (between the surge tank 8 and the air cleaner 9).
[0016]
Further, an air flow meter AFM is provided in the air supply pipe L1 so as to be located between the air cleaner 9 and the throttle valve 10. A bypass pipe (air supply path) L2 is branched from the air supply pipe L1 at a branch portion BP defined between the throttle valve 10 and the air flow meter AFM. The bypass pipe L2 has an air pump 11 and an on-off valve 12 in the order from the branch portion BP side, and the tip thereof (the end opposite to the end on the branch portion BP side) has the reforming property according to the present invention. (Reformer) 20. As the on-off valve 12, an electromagnetic valve or a motor valve is used.
[0017]
As shown in FIG. 2, the reformer 20 has a cylindrical main body 21 having both ends closed. A region on one end side (right end side in FIG. 2) of the main body 21 is defined as a mixing chamber 22, and the air from the bypass pipe L <b> 2 and the fuel injection valve 15 are injected into the mixing chamber 22. A mixture with fuel is introduced. Further, inside the main body 21 of the reformer 20, a reforming reaction section 23 is defined so as to be adjacent to the mixing chamber 22, and the reforming reaction section 23 has, for example, zirconia loaded with rhodium. A reforming catalyst is provided. Furthermore, inside the main body 21 of the reformer 20, a reformed gas distribution chamber (reformed gas supply unit) 24 is defined. The reformed gas distribution chamber 24 is located on the opposite side of the mixing chamber 22 across the reforming reaction section 23, that is, on the downstream side of the reforming reaction section 23.
[0018]
As shown in FIGS. 1 and 2, one end of the number of pipes 25 corresponding to the number of combustion chambers 3 of the engine 1 (four chambers in the present embodiment) is provided in the main body 21 of the reformer 20. Are connected so as to communicate with the reformed gas distribution chamber 24. As shown in FIGS. 1 and 2, the other end of each pipe 25 is connected to one corresponding intake pipe 5a. Thus, the intake port of each combustion chamber 3 of the engine 1 can communicate with the inside of the reformed gas distribution chamber 24 via the intake pipe 5a and the pipe 25.
[0019]
A fuel injection valve 15 for supplying fuel to the reformer 20 is connected to a fuel tank via a fuel pump (not shown), and is capable of injecting hydrocarbon fuel such as gasoline. As shown in FIG. 3, the fuel injection valve 15 is housed inside a valve housing 26 connected to the main body 21 of the reformer 20. The distal end of the bypass pipe L2 including the air pump 11 and the on-off valve 12 is connected to the valve housing 26 so that air is blown into the vicinity of the fuel injection hole 15a of the fuel injection valve 15 in the valve housing 26. ing. That is, the bypass pipe L2 is connected to the valve housing 26 so that air is blown from the side to the fuel injection valve 15 (fuel injection hole 15a).
[0020]
A nozzle member 16 is connected to a tip of the fuel injection valve 15. The nozzle member 16 has a plurality of air injection holes 16a radially formed in the radial direction, and a nozzle mixing chamber 16b formed to extend in the axial direction and communicate with each air injection hole 16a. The nozzle mixing chamber 16b of the nozzle member 16 communicates with the inside of the mixing chamber 22 of the reformer 20, as shown in FIG. O-rings 17a and 17b are interposed between the valve housing 26 and the fuel injection valve 15 and the nozzle member 16 to prevent fuel and air from leaking outside.
[0021]
On the other hand, a sleeve 27 is fixed to the main body 21 of the reformer 20 so as to cover the periphery of the mixing chamber 22. The sleeve 27 is formed so that the outer diameter gradually increases from one end side to the other end side (from the valve accommodating section 26 to the reforming reaction section 23), and the liquid is filled in one place inside the sleeve 27. It is configured to be easy to accumulate. A fuel trapping chamber 28 is defined between the inner wall surface of the sleeve 27 and the outer peripheral face of the main body 21 so as to be located on the outer periphery of the mixing chamber 22. The mixing chamber 22 and the fuel trapping chamber 28 Communicate with each other through a plurality of holes 21a formed in the holes. Gas-liquid separation fins 29 are fixed around the hole 21a of the main body 21. The gas-liquid separation fins 29 are formed and arranged so that liquid around the hole 21a can be guided into the hole 21a.
[0022]
Further, one end of a connection pipe (connection path) L3 having the on-off valve 18 in the middle is connected to the periphery of the portion of the sleeve 27 having the largest outer diameter. The other end of the connection pipe L3 is connected to the bypass pipe L2 on the downstream side of the on-off valve 12, and the fuel capturing chamber 28 and the bypass pipe L2 can communicate with each other via the connection pipe L3. As shown in FIG. 3, inside the bypass pipe L2, a Venturi pipe 19 having a narrowest part (throat part) with the smallest inner diameter at the center in the longitudinal direction is fixed, and the connection pipe L3 is a Venturi pipe. The Venturi tube 19 penetrates the center in the longitudinal direction, and its tip is viewed from the vicinity of the narrowest portion of the Venturi tube 19 into the bypass tube L2. In addition, as the on-off valve 18, a solenoid valve, a motor valve, or the like is employed.
[0023]
Now, as shown in FIG. 1, the engine 1 of the vehicle C includes an electronic control unit (hereinafter, referred to as “ECU”) 30 functioning as control means. The ECU 30 includes a CPU, a ROM, a RAM, an input / output port, a storage device, and the like, all of which are not shown. The ECU 30 includes the above-described ignition plug (igniter) 7, a valve mechanism (not shown), a throttle valve 10, an air pump 11, an on-off valve 12 for a bypass pipe L2, a fuel injection valve 15, an on-off valve 18 for a connection pipe L3, and an air flow meter. An AFM or the like is connected, and the ECU 30 controls these devices in accordance with detection values of various sensors that detect the operating state of the engine 1, various control programs, maps, and the like.
[0024]
When operating the vehicle C configured as described above, the ECU 30 operates the fuel injection valve 15 to start fuel injection to the reformer 20, and at the same time, opens the on-off valve 12 and activates the air pump 11 By operating, the air supply from the bypass pipe L2 to the reformer 20 is started. Thereby, the air pump 11 sucks in air from the air supply pipe L1 via the bypass pipe L2 and discharges it. The air discharged from the air pump 11 is sent from the bypass pipe L2 to the vicinity of the fuel injection hole 15a of the fuel injection valve 15 in the valve accommodating portion 26, and is supplied to the nozzle mixing chamber 16b through each air injection hole 16a of the nozzle member 16. Reach. The air from the bypass pipe L2 mixes with the hydrocarbon-based fuel injected from the fuel injection holes 15a in the nozzle mixing chamber 16b of the nozzle member 16, and flows into the mixing chamber 22 of the reformer 20.
[0025]
The mixture of the fuel and the air supplied from the nozzle member 16 into the mixing chamber 22 flows toward the reforming reaction section 23 as indicated by the white arrow in FIG. Here, in the case where the temperature of the reforming catalyst in the reforming reaction section 23 is not sufficiently high, after being injected from the fuel injection hole 15a, the fuel which is vaporized in the nozzle mixing chamber 16b and mixed with the air, It may be liquefied before reaching the reforming reaction section 23, and the liquefied fuel may adhere to the inner wall surface of the mixing chamber 22 (main body 21).
[0026]
In view of this point, in the reformer 20, as described above, the fuel trapping chamber 28 communicating with the mixing chamber 22 through the plurality of holes 21a is defined on the outer periphery of the mixing chamber 22, and Gas-liquid separation fins 29 are arranged around the hole 21a, and the fuel capture chamber 28 and the gas-liquid separation fins 29 function as liquefied fuel recovery means. That is, in the reformer 20 according to the present invention, even if the fuel flows from the nozzle member 16 into the mixing chamber 22 and then liquefies before reaching the reforming reaction section 23, the liquid that has reached the inner wall surface of the mixing chamber 22 The fuel is separated from the air-fuel mixture by the gas-liquid separation fins 29, guided to the holes 21 a, and flows into the fuel trapping chamber 28.
[0027]
As a result, in the reformer 20, it is possible to reliably prevent the liquefied fuel from flowing into the reforming reaction section 23. Therefore, according to the reformer 20, a mixture of the fuel and the air, which are uniformly mixed, can be stably supplied to the reforming reaction section 23, so that a desired reforming efficiency, that is, an amount close to the theoretical value can be obtained. Reformed gas can be obtained. Further, in the reformer 20, since the liquefied fuel is reliably prevented from flowing into the reforming reaction section 23, the amount of unreformed fuel (unreformed HC) from the reformer 20 is extremely reduced. It is also possible. As a result, unreformed HC and the like in the exhaust gas of the engine 1 can be brought close to zero.
[0028]
The fuel liquefied as described above is separated and recovered, and the air-fuel mixture in the mixing chamber 22 in which the vaporized fuel and air are uniformly mixed flows into the reforming reaction unit 23. In the reforming reaction section 23, the hydrocarbon-based fuel and air are reacted by the reforming catalyst, and the partial oxidation reaction represented by the following equation (1) proceeds.
C _m H _n + (m / 2) O ₂ → mCO + (n / 2) H ₂ (1)
Then, as the reaction of the above formula (1) proceeds, a reformed gas containing CO and H ₂ as combustion components is generated, and the obtained reformed gas is supplied from the reformed gas distribution chamber 24 to the pipe line. The air is supplied to the inside of each of the intake pipes 5a through the air inlet 25.
[0029]
Air is introduced into the surge tank 8 through the throttle valve 10 of the air supply pipe L1 whose opening is adjusted by the ECU 30, and the air in the surge tank 8 is distributed into each intake pipe 5a. Therefore, the reformed gas introduced into each intake pipe 5a from the reformed gas distribution chamber 24 is mixed with the air in the intake pipe 5a, and then sucked into each combustion chamber 3. In the present embodiment, since air to the reformer 20 is taken out from the air supply pipe L1 downstream of the air flow meter AFM and the indicated value of the air flow meter AFM indicates the total intake air amount of the engine 1, the combustion of each combustion The air-fuel ratio control in the chamber 3 can be performed well.
[0030]
When a mixture of reformed gas and air is supplied to each fuel chamber 3 and each ignition plug 7 is ignited at a predetermined timing, the combustion components CO and H ₂ are burned in each combustion chamber 3. Then, the piston 4 is reciprocated. As a result, the engine 1 operates, and the wheels W are rotationally driven via the transaxle T including the torque converter, the transmission, the differential mechanism, and the like.
[0031]
Further, the ECU 30 opens the on-off valve 18 of the connection pipe L3 at the stage when the supply of the air-fuel mixture to the reformer 20 is started and the reforming reaction is started in the reforming reaction section 23, and the fuel trapping chamber 28 And the bypass pipe L2. At this time, a negative pressure is generated near the end of the connection pipe L3 on the side of the bypass pipe L2 by the venturi pipe 19 in the bypass pipe L2. The fuel vaporized in the fuel trap chamber 28 is sucked into the bypass pipe L2 via the connection pipe L3.
[0032]
As a result, the liquefied fuel in the fuel trap chamber 28 and the fuel vaporized there are ejected from the end of the connecting pipe L3 into the bypass pipe L2 by the action of the venturi pipe 19, and are converted into air flowing through the bypass pipe L2. Mix evenly. As a result, in the reformer 20, it is possible to uniformly mix the fuel collected in the fuel trap chamber 28 with the air in the bypass pipe L2 and to resupply the fuel from the mixing chamber 22 to the reforming reaction section 23. Become. In the present embodiment, the ECU 30 closes the on-off valve 18 of the connection pipe L3 when the supply of the air-fuel mixture to the reformer 20 is stopped and the reforming reaction in the reforming reaction unit 23 is stopped. The resupply of the fuel in the fuel trapping chamber 28 to the reforming reaction section 23 via the connection pipe L3 is stopped.
[0033]
FIG. 4 is an enlarged sectional view showing another embodiment of the fuel reformer according to the present invention. In the reformer 20A shown in FIG. 4, the sleeve 27A that defines the fuel trapping chamber 28 together with the main body 21 extends not only so as to cover not only the outer periphery of the mixing chamber 22 but also the outer periphery of the reforming reaction section 23 so that its length is longer. Is extended in the direction. Thereby, in the reformer 20A, the fuel capture chamber 28 is defined around the mixing chamber 22 and the reforming reaction section 23. In this case, the outer diameter of the sleeve 27A is formed so as to gradually increase from both ends toward the center, and the liquid is easily accumulated near the center in the longitudinal direction. The connection pipe L3 is connected near the center of the sleeve 27A where the outer diameter is the largest.
[0034]
In the reformer 20A thus configured, since the fuel trapping chamber 28 is also formed on the outer periphery of the reforming reaction section 23, the heat generated in the reforming reaction section 23 due to the reforming reaction is generated by the main body 21. Through the fuel trap chamber 28. Therefore, according to the reformer 20A, it is possible to vaporize the liquid fuel remaining in the fuel trap chamber 28 by using the heat generated in the reforming reaction section 23.
[0035]
The fuel vaporized in the fuel trap chamber 28 is ejected from the end of the connection pipe L3 to the air in the bypass pipe L2 by the action of the venturi pipe 19, and is uniformly mixed with the air flowing through the bypass pipe L2. Mix. As a result, according to the reformer 20A, the fuel collected in the fuel trapping chamber 28 is mixed with the air in the bypass pipe L2 extremely and uniformly, and then the fuel is recovered from the mixing chamber 22 to the reforming reaction section 23. Can be resupplied. In addition, in the reformer 20A of FIG. 4, the on-off valve 18 of the connection pipe L3 may be omitted.
[0036]
FIG. 5 is an enlarged sectional view showing still another embodiment of the fuel reformer according to the present invention. The reformer 20B shown in FIG. 5 has basically the same configuration as the reformer 20 shown in FIG. 3 and the like, but the inside of the fuel trapping chamber 28 of the reformer 20B contains zeolite. An adsorbent 40 capable of adsorbing a hydrocarbon (fuel) such as carbon or activated carbon is disposed. In the present embodiment, the adsorbent 40 is arranged near the portion of the sleeve 27 having the largest outer diameter so as to be continuous with the end of the connection pipe L3.
[0037]
In the reformer 20B configured as described above, the liquid fuel collected in the fuel capturing chamber 28 by the gas-liquid separation fins 29 and the like is adsorbed by the adsorbent 40, so that the efficiency of capturing the liquefied fuel is improved. It becomes possible. Further, the fuel (hydrocarbon) adsorbed by the adsorbent 40 is vaporized and desorbed from the adsorbent 40 when the ambient temperature of the adsorbent 40 becomes equal to or higher than a predetermined temperature. Therefore, in the reformer 20B, it is possible to reliably prevent the fuel collected in the fuel trapping chamber 28 from flowing into the bypass pipe L2 from the connection pipe L3 in a liquid state. As a result, also by the reformer 20B, the fuel collected in the fuel trapping chamber 28 is mixed with the air in the bypass pipe L2 extremely and uniformly, and then the fuel is recovered from the mixing chamber 22 to the reforming reaction section 23. It becomes possible to supply again.
[0038]
Further, in the reformer 20B, when the operation of the air pump 11 and the fuel injection valve 15 is stopped and the supply of the air-fuel mixture to the reformer 20B is stopped, the hydrocarbon remaining in the mixing chamber 22 is removed. The fuel is adsorbed by the adsorbent 40 in the fuel trap chamber 28. Therefore, in the reformer 20B, after the supply of the air-fuel mixture to the reforming reaction section 23 is stopped, the reforming reaction in the reforming reaction section 23 can be stopped immediately.
[0039]
【The invention's effect】
As described above, according to the present invention, it is possible to realize a fuel reforming apparatus capable of reliably preventing liquefied fuel from flowing into a reforming catalyst and improving reforming efficiency.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram for explaining a fuel reformer according to the present invention.
FIG. 2 is a schematic configuration diagram for explaining a fuel reforming apparatus according to the present invention.
FIG. 3 is an enlarged sectional view showing a fuel reforming apparatus according to the present invention.
FIG. 4 is an enlarged sectional view showing another embodiment of the fuel reforming apparatus according to the present invention.
FIG. 5 is an enlarged sectional view showing still another embodiment of the fuel reforming apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Engine 3 Combustion chamber 11 Air pump 12, 18 On-off valve 15 Fuel injection valve 19 Venturi pipe 20, 20A, 20B Reformer 21 Main body 22 Mixing chamber 23 Reforming reaction part 24 Reformed gas distribution chamber 26 Valve accommodation parts 27, 27A Sleeve 28 Fuel trap chamber 29 Gas-liquid separation fin 30 ECU
40 Adsorbent C Vehicle L1 Air supply pipe L2 Bypass pipe L3 Connecting pipe

Claims (4)

In a fuel reformer for reforming a mixture of fuel and air,
A reforming reaction section including a reforming catalyst for reforming the air-fuel mixture;
A fuel reforming apparatus comprising: a liquefied fuel recovery unit configured to recover liquefied fuel before being introduced into the reforming reaction unit. 2. The air conditioner according to claim 1, further comprising an air supply path for supplying air to the reforming reaction unit, and a connection path connecting the liquefied fuel recovery unit and the air supply path. 3. Fuel reformer. 3. The fuel reformer according to claim 1, wherein the liquefied fuel recovery unit can vaporize the recovered fuel using heat generated in the reforming reaction unit. 4. 4. The fuel reformer according to claim 1, wherein the liquefied fuel recovery unit further includes an adsorbent capable of adsorbing the liquefied fuel.

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