JP2015218644A - Fuel supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel supply system capable of treating reformed fuel generated in a reformer after stopping of an internal combustion engine.SOLUTION: A fuel supply system comprises: a reformer 33 provided in exhaust passages 41, 42, and 43 of an internal combustion engine 10 and reforming raw fuel to reformed fuel by exhaust heat of the internal combustion engine 10; an exhaust emission control device 34 provided in the exhaust passages 41, 42, and 43 of the internal combustion engine 10 and purifying exhaust gas of the internal combustion engine 10; a reformed-fuel introduction passage 47 connected to the reformer 33 and introducing the reformed fuel to an intake passage 40 of the internal combustion engine 10; a reformed-fuel discharge passage 48 connected to the reformer 33 and introducing the reformed fuel to the exhaust emission control device 34; and a first open/close mechanism 47a opening or closing the reformed-fuel discharge passage 48.

Description

  The present invention relates to a fuel supply system that generates reformed fuel from a hydrocarbon-based raw fuel by a reforming catalyst and supplies the generated reformed fuel to an internal combustion engine.

  Conventionally, this type of fuel supply system is disclosed in Patent Document 1. In the fuel supply system described in Patent Document 1, a reformer is provided in the exhaust passage, and the raw fuel (methane) is converted into reformed fuel (hydrogen and carbon monoxide), which is a fuel having a larger calorific value, by exhaust heat. It is reformed and introduced into the intake air for combustion.

JP 2001-241364 A

  In the fuel supply system of Patent Document 1, reforming of the raw fuel is continued by the raw fuel and heat remaining in the reformer even after the internal combustion engine is stopped, and reformed fuel is generated. Then, the generated reformed fuel may flow back through the intake passage and leak to the outside, or the intake passage may be filled and abnormal combustion may occur at the next start.

  The present invention has been made to solve the above-described problems, and a main object of the present invention is to provide a fuel supply system capable of processing the reformed fuel generated by the reformer after the internal combustion engine is stopped. There is.

  The present invention is a fuel supply system, provided in an exhaust passage of an internal combustion engine, provided in a reformer for reforming raw fuel into reformed fuel by exhaust heat of the internal combustion engine, and an exhaust passage of the internal combustion engine. An exhaust gas purification device that purifies the exhaust gas of the internal combustion engine; and a reformer; a reformed fuel introduction passage that introduces reformed fuel into the intake passage of the internal combustion engine; and a reformer that is connected to the reformer, It is characterized by comprising a reformed fuel discharge passage to be introduced into the exhaust purification device and a first opening / closing mechanism for opening and closing the reformed fuel discharge passage.

  According to the above configuration, when the internal combustion engine is stopped, the reformed fuel can be introduced into the exhaust purification device via the reformed fuel discharge passage, and the reformed gas can be oxidized by the exhaust purification device. Therefore, after the internal combustion engine is stopped, the reformed gas generated by the raw fuel and exhaust heat remaining in the reformer flows backward in the intake passage and leaks to the outside, or the intake passage is filled and the next time The occurrence of abnormal combustion at the start can be suppressed.

The structure of the electric power generation system which concerns on 1st Embodiment is shown. The flow path at the time of operation | movement of the internal combustion engine in 1st Embodiment is shown. The flow path at the time of the stop of an internal combustion engine in 1st Embodiment is shown. The structure of the electric power generation system which concerns on 2nd Embodiment is shown. The flow path at the time of operation | movement of an internal combustion engine in 2nd Embodiment is shown. The flow path at the time of the stop of an internal combustion engine in 2nd Embodiment is shown. The structure of the electric power generation system which concerns on 3rd Embodiment is shown. The flow path at the time of operation | movement of the internal combustion engine in 3rd Embodiment is shown. The flow path at the time of the stop of an internal combustion engine in 3rd Embodiment is shown. The structure of the electric power generation system which concerns on 4th Embodiment is shown. The flow path at the time of insufficient heat quantity in 4th Embodiment is shown.

  Hereinafter, each embodiment will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals in the drawings, and the description of the same reference numerals is used.

<First Embodiment>
FIG. 1 shows a power generation system according to this embodiment. The power generation system is configured to include a fuel supply system, and is a system that generates power by using power obtained by reforming raw fuel into reformed fuel and burning the reformed fuel.

  The power generation system includes an internal combustion engine 10, an air cleaner 30, a raw fuel tank 31, a raw fuel carburetor 32, a reformer 33, and an exhaust purification device 34. The internal combustion engine 10 is a diesel engine. The air cleaner 30 removes dust and the like from the external air and takes clean air into the power generation system. The raw fuel tank 31 stores raw fuel that is liquid fuel. The raw fuel carburetor 32 includes a raw fuel flow path therein, and evaporates liquid raw fuel to change it into gaseous raw fuel. The reformer 33 includes an exhaust passage 33a and a fuel passage 33b, and heat exchange is possible between a fluid passing through the exhaust passage 33a and a fluid passing through the fuel passage 33b. The exhaust purification device 34 includes a catalyst for purifying exhaust.

  The internal combustion engine 10 includes a cylinder block 11 and a cylinder head 12. A cylinder 13 is formed in the cylinder block 11, and a piston 14 that reciprocates in the vertical direction with respect to the cylinder 13 is disposed in the cylinder 13. The piston 14 is connected to the crankshaft 16 via a connecting rod 15. A combustion chamber 17 defined by a cylinder block 11 and a cylinder head 12 is provided above the piston 14. The combustion chamber 17 is connected to an intake port formed in the cylinder head 12 via an intake valve 18 and an exhaust valve 19. 20 and the exhaust port 21. Further, the cylinder head 12 is provided with an auxiliary fuel supply device 22 for supplying auxiliary fuel to the combustion chamber 17. As the auxiliary fuel, light oil or the like capable of compression ignition is used.

  A power generator (not shown) is connected to the crankshaft 16, and power is generated by the power generator by the rotation of the crankshaft 16 as the piston 14 moves up and down, and power is supplied to an external device or a power storage device.

  The intake port 20 of the internal combustion engine 10 is connected to the air cleaner 30 via the intake passage 40, and the exhaust port 21 of the internal combustion engine 10 is connected to the exhaust passage 33 a of the reformer 33 via the first exhaust passage 41. Connected to the exhaust inlet. On the other hand, the exhaust outlet of the exhaust passage 33 a of the reformer 33 is connected to the exhaust inlet of the exhaust purification device 34 by the second exhaust passage 42, and the purification exhaust outlet of the exhaust purification device 34 is connected to the third exhaust passage 43. It is connected to the.

  The raw fuel tank 31 is connected to the raw fuel inlet of the raw fuel carburetor 32 via a raw fuel passage 44 provided with a fuel pump 44a for delivering raw fuel. The vaporized raw fuel outlet of the raw fuel carburetor 32 is connected to the fuel supply port of the fuel passage 33 b of the reformer 33 via the vaporized raw fuel passage 45. The vaporized raw fuel passage 45 is provided with a fuel cutoff valve 45 a that adjusts or cuts off the amount of raw fuel flowing from the raw fuel carburetor 32 to the fuel passage 33 b of the reformer 33. The fuel cutoff valve 45 a has a function of a third opening / closing mechanism that opens and closes the vaporized raw fuel passage 45 that supplies raw fuel to the reformer 33. The raw fuel carburetor 32 is connected to the internal combustion engine 10 via the heat exchange passages 46a and 46b, and heat generated in the internal combustion engine 10 can be supplied to the raw fuel flowing through the raw fuel carburetor 32. It has become a structure. A reformed fuel outlet of the fuel passage 33 b of the reformer 33 is connected to an intake passage 40 interposed between the air cleaner 30 and the intake port 20 via a reformed fuel introduction passage 47.

  On the other hand, the reformed fuel introduction passage 47 is provided with two branch portions, and the reformed fuel discharge passage 48 has a second branch portion on the reformed fuel outlet side branch portion of the fuel passage 33b of the reformer 33. One end is connected, and the first end of the air introduction passage 49 is connected to the branch portion on the intake passage 40 side. On the other hand, the second end of the reformed fuel discharge passage 48 is connected to the second exhaust passage 42, and the second end of the air introduction passage 49 is connected to the first end and the second end of the reformed fuel discharge passage 48. Connected between.

  At the connecting portion between the reformed fuel introduction passage 47 and the reformed fuel discharge passage 48, either the reformed fuel introduction passage 47 or the reformed fuel discharge passage 48 is closed, thereby providing a reformed fuel flow path. A passage switching valve 47 a that switches to either the reformed fuel introduction passage 47 or the reformed fuel discharge passage 48 is provided. That is, the passage switching valve 47 a has a function of a first opening / closing mechanism that opens and closes the reformed fuel discharge passage 48 and a function of a second opening / closing mechanism that opens and closes the reformed fuel introduction passage 47.

  The air introduction passage 49 includes a blower 49 a that sends air from the air introduction passage 49 to the reformed fuel discharge passage 48 by rotation of the blower fan, and an air amount that is sent from the air introduction passage 49 to the reformed fuel discharge passage 48. And an air shut-off valve 49b for shutting off the air introduction passage 49 and the reformed fuel discharge passage 48 are provided. The air shut-off valve 49b functions as a fourth opening / closing mechanism that opens and closes the air introduction passage 49.

  Further, the internal combustion engine 10 is provided with a crank angle sensor 60 that detects the number of rotations of the crankshaft 16 of the internal combustion engine 10 as a measuring device, and a temperature sensor that detects the exhaust temperature is provided in the third exhaust passage 43. 61 is provided.

  The power generation system includes a control device 70, and the rotational speed of the crankshaft 16 of the internal combustion engine 10 detected by the crank angle sensor 60 and the exhaust temperature detected by the temperature sensor 61 are input to the control device 70. Further, based on a power generation system drive command input from the outside or a power generation system drive command generated in the control device, the fuel pump 44a, the fuel cutoff valve 45a, the passage switching valve 47a, the blower 49a, the air cutoff A control signal is transmitted to the valve 49b. Here, the control device 70 functions as a fuel passage control device by performing opening / closing control of the passage switching valve 47a, and functions as an air passage control device by performing opening / closing control of the air cutoff valve 49b.

  In the power generation system according to the present embodiment, the raw fuel supplied from the raw fuel tank 31 is methanol. The methanol supplied from the raw fuel tank 31 to the reformer 33 is reformed in the reformer 33 into hydrogen and carbon monoxide by a chemical reaction that is an endothermic reaction shown in the following thermochemical equation 1. . The hydrogen and carbon monoxide produced by this chemical reaction become the reformed fuel.

排気浄化装置３４では、触媒により、下記熱化学方程式２に示す発熱反応である化学反応により、改質燃料を酸化する。

In the exhaust purification device 34, the reformed fuel is oxidized by a catalyst by a chemical reaction that is an exothermic reaction shown in the following thermochemical equation 2.

図２は、本実施形態に係る発電システムにおいて、内燃機関１０へ改質燃料及び副燃料を供給して燃焼させて発電を行う際の、内燃機関１０の運転時の、原燃料、改質燃料、空気及び排気の通路を示している。制御装置７０から送信される制御信号により、燃料遮断弁４５ａは気化原燃料通路４５を開放しており、通路切替弁４７ａは、改質燃料導入通路４７を開放し、改質燃料排出通路４８を閉塞している。また、空気遮断弁４９ｂは空気導入通路４９を閉塞している。

FIG. 2 shows the raw fuel and the reformed fuel during operation of the internal combustion engine 10 when generating power by supplying the reformed fuel and auxiliary fuel to the internal combustion engine 10 and burning them in the power generation system according to the present embodiment. Figure 2 shows air and exhaust passages. The fuel cutoff valve 45a opens the vaporized raw fuel passage 45 by a control signal transmitted from the control device 70, and the passage switching valve 47a opens the reformed fuel introduction passage 47 and opens the reformed fuel discharge passage 48. Blocked. The air shut-off valve 49b closes the air introduction passage 49.

  First, the fuel pump 44 a is operated by the control signal transmitted from the control device 70 to the fuel pump 44 a, and the raw fuel stored in the raw fuel tank 31 is supplied to the raw fuel carburetor 32 through the raw fuel passage 44. Is done. The raw fuel supplied to the raw fuel carburetor 32 is vaporized by heat flowing from the internal combustion engine 10 through the heat exchange passages 46a and 46b. The vaporized raw fuel is supplied to the raw fuel inlet of the fuel passage 33b of the reformer 33 through the vaporized raw fuel passage 45, passes through the fuel passage 33b of the reformer 33, and is modified by the above-described chemical reaction. It is reformed to quality fuel. The reformed fuel sent from the reformed fuel outlet of the fuel passage 33 b of the reformer 33 passes through the reformed fuel introduction passage 47 and flows into the intake passage 40. On the other hand, the air sucked from the air cleaner 30 also flows into the intake passage 40. In the intake passage 40, the reformed fuel and air are mixed to form an air-fuel mixture, and the air-fuel mixture is supplied to the intake port 20.

  The air-fuel mixture supplied to the intake port 20 flows into the combustion chamber 17 as the intake valve 18 is opened during the intake stroke. In the compression stroke, as the piston 14 rises, the air-fuel mixture is compressed, and the inside of the combustion chamber 17 becomes high temperature and pressure. Here, if the crank angle sensor 60 detects that the piston 14 has risen to near the top dead center, the auxiliary fuel is supplied from the auxiliary fuel supply device 22 into the combustion chamber 17 in accordance with a command from the control device 70. The The supplied secondary fuel is self-ignited in a high-temperature and high-pressure environment, and the generated flame propagates to the reformed fuel and the reformed fuel is burned. As a result of the combustion of the auxiliary fuel and the reformed fuel, the air-fuel mixture in the combustion chamber 17 expands and the piston 14 descends. When the piston 14 moves down to near the bottom dead center, the exhaust valve 19 is opened and the exhaust is discharged from the exhaust port 21.

  The exhaust discharged from the exhaust port 21 flows into the exhaust inlet of the exhaust passage 33a of the reformer 33 through the first exhaust passage 41, and exchanges heat with the raw fuel in the fuel passage 33b of the reformer 33. After that, it flows from the exhaust outlet of the exhaust passage 33a of the reformer 33 to the exhaust inlet of the exhaust purification device 34 through the second exhaust passage 42 and is purified. The purified exhaust gas is discharged from the purified exhaust outlet of the exhaust purification device 34 to the outside through the third exhaust passage 43.

  FIG. 3 shows the reformed fuel, air, and exhaust passages when the internal combustion engine 10 is stopped in the power generation system according to the present embodiment. By the control signal transmitted from the control device 70, the fuel cutoff valve 45a closes the vaporized raw fuel passage 45, the passage switching valve 47a closes the reformed fuel introduction passage 47, and the reformed fuel discharge passage 48. It is open. The air shut-off valve 49b opens the air introduction passage 49.

  Since the fuel cutoff valve 45a is closed, the supply of raw fuel to the reformer 33 is stopped. However, raw fuel remains in the reformer 33 and heat also remains. Therefore, the reforming reaction continues in the reformer 33, and reformed fuel is generated. The generated reformed fuel flows into the reformed fuel discharge passage 48.

  On the other hand, the air flowing from the air cleaner 30 flows backward through the reformed fuel introduction passage 47 and flows into the air introduction passage 49. In the air introduction passage 49, the blower 49 a is operated by a control signal from the control device 70, and the inflowing air is sent to the reformed fuel discharge passage 48.

  The reformed fuel that has joined the air in the reformed fuel discharge passage 48 flows into the exhaust purification device 34 through the second exhaust passage 42. The reformed fuel that has flowed into the exhaust purification device 34 is oxidized by the chemical reaction of the thermochemical equation 2 described above, and is discharged to the outside through the third exhaust passage 43.

  By the way, as shown in the thermochemical equation 2 above, the chemical reaction occurring in the exhaust purification device 34 is an exothermic reaction. Therefore, it is possible to estimate the amount of reformed fuel flowing into the exhaust purification device 34 by detecting the change with time of the exhaust temperature by the temperature sensor 61. The control device 70 approximates the amount of reformed fuel that flows into the exhaust purification device 34 based on the exhaust temperature detected by the temperature sensor 61. Then, the rotational speed of the blower fan of the blower 49a and the air shutoff valve 49b are set so that the amount of air introduced from the air introduction passage 49 to the reformed fuel discharge passage 48 is sufficient for oxidizing the reformed fuel. To control the opening degree.

  With the above configuration, the fuel supply system according to the present embodiment has the following effects.

  (1) When the internal combustion engine 10 is stopped, the reformed fuel can be introduced into the exhaust purification device 34 via the reformed fuel discharge passage 48, and the reformed fuel can be oxidized by the exhaust purification device 34. Therefore, after the internal combustion engine 10 is stopped, the reformed fuel generated by the raw fuel remaining in the reformer 33 and the exhaust heat flows back through the intake passage 40 and leaks to the outside or fills the intake passage 40. Thus, occurrence of abnormal combustion at the next start-up can be suppressed.

  (2) If the supply of the raw fuel to the reformer 33 is continued when the internal combustion engine 10 is stopped, the reforming is performed by the exhaust heat remaining in the reformer 33 and the supplied raw fuel. Fuel will be generated. In the present embodiment, since the supply of raw fuel to the reformer 33 is shut off when the internal combustion engine 10 is stopped, the reformed fuel generated in the reformer 33 after the internal combustion engine 10 is stopped is the reformer 33. It is only produced from the raw fuel remaining inside. Therefore, the amount of reformed fuel produced after the internal combustion engine 10 is stopped can be reduced.

  (3) When the reformed fuel is introduced into the exhaust purification device 34, an oxidation reaction of the reformed fuel is performed. However, when oxygen sufficient for the oxidation reaction of the reformed fuel is not introduced into the exhaust purification catalyst, the reformed fuel that has not been oxidized is discharged from the exhaust purification device 34. In this embodiment, since the air introduction passage 49 for introducing air into the reformed fuel discharge passage 48 is provided, the reformed fuel introduced into the exhaust purification device 34 through the reformed fuel discharge passage 48 is sufficiently oxidized. As a result, discharge of the non-oxidized reformed fuel from the exhaust purification device 34 can be suppressed. In addition, since the air shut-off valve 49 b is provided in the air introduction passage 49, it is possible to prevent exhaust from flowing back through the air introduction passage 49 when the internal combustion engine 10 is operating.

Second Embodiment
FIG. 4 shows a power generation system according to this embodiment. Similar to the power generation system according to the first embodiment, the power generation system is configured to include a fuel supply system, and the power obtained by reforming raw fuel into reformed fuel and burning the reformed fuel. It is a system that generates electricity by

  In addition to the internal combustion engine 10, the air cleaner 30, the raw fuel tank 31, the raw fuel carburetor 32, the reformer 33, and the exhaust purification device 34, the power generation system includes a turbocharger 35 and an air reservoir 36. It is comprised including. The turbocharger 35 is constituted by a compressor 35a and a turbine 35c connected by the compressor 35a and a rotating shaft 35b. The air reservoir 36 accumulates compressed air inside.

  The intake port 20 of the internal combustion engine 10 is connected to the air cleaner 30 via an intake passage 40 ', and the exhaust port 21 of the internal combustion engine 10 is exhausted from the reformer 33 via a first exhaust passage 41'. It is connected to the exhaust inlet of the passage 33a. A compressor 35a and a turbine 35c of the turbocharger 35 are provided in the intake passage 40 'and the first exhaust passage 41', respectively. The exhaust outlet of the exhaust passage 33 a of the reformer 33 is connected to the exhaust inlet of the exhaust purification device 34 by the second exhaust passage 42, and the purified exhaust outlet of the exhaust purification device 34 is connected to the third exhaust passage 43. ing.

  The raw fuel tank 31 is connected to the raw fuel inlet of the raw fuel carburetor 32 through a raw fuel passage 44 provided with a fuel pump 44a for sending out raw fuel and a fuel cutoff valve 44b. The fuel cutoff valve 44 b has a function of a third opening / closing mechanism that switches between opening and closing of the raw fuel passage 44. On the other hand, the vaporized raw fuel outlet of the raw fuel carburetor 32 is connected to the raw fuel inlet of the fuel passage 33 b of the reformer 33 via the vaporized raw fuel passage 45. The raw fuel carburetor 32 is connected to the internal combustion engine 10 via the heat exchange passages 46a and 46b so as to be able to exchange heat. The reformed fuel outlet of the fuel passage 33 b of the reformer 33 is connected to an intake passage 40 ′ interposed between the compressor 35 a of the turbocharger 35 and the intake port 20 via the reformed fuel introduction passage 47. ing.

  The reformed fuel introduction passage 47 is provided with a branch portion, and the first end of the reformed fuel discharge passage 48 is connected to the branch portion. The second end of the reformed fuel discharge passage 48 is connected to the second exhaust passage 42. At the connecting portion between the reformed fuel introduction passage 47 and the reformed fuel discharge passage 48, either the reformed fuel introduction passage 47 or the reformed fuel discharge passage 48 is closed, thereby providing a reformed fuel flow path. A passage switching valve 47 a that switches to either the reformed fuel introduction passage 47 or the reformed fuel discharge passage 48 is provided. That is, the passage switching valve 47 a has a function of a first opening / closing mechanism that opens and closes the reformed fuel discharge passage 48 and a function of a second opening / closing mechanism that opens and closes the reformed fuel introduction passage 47.

  A branch portion is provided between the compressor 35a and a branch portion of the intake passage 40 'with the reformed fuel introduction passage 47, and an air inflow passage provided with a check valve 50a in the branch portion. 50 first ends are connected. On the other hand, the second end of the air inflow passage 50 is connected to the air inflow portion of the air reservoir 36. The check valve 50a is attached in such a direction as to allow inflow of air from the intake passage 40 'to the air reservoir 36 and to block outflow of air from the air reservoir 36 to the intake passage 40'.

  A first end of an air introduction passage 51 provided with an air shutoff valve 51 a is connected to the air outflow portion of the air reservoir 36. The second end of the air introduction passage 51 is connected to the raw fuel flow path inside the raw fuel carburetor 32. The air shut-off valve 51 a functions as a fourth opening / closing mechanism that opens and closes the air introduction passage 51.

  The control device 70 included in the power generation system includes a fuel pump 44a, a fuel cutoff valve 44b, and a passage switch based on a power generation system drive command input from the outside or a power generation system drive command generated in the control device 70. A control signal is transmitted to the valve 47a and the air cutoff valve 51a. Here, the control device 70 functions as a fuel passage control device by performing opening / closing control of the passage switching valve 47a, and functions as an air passage control device by performing opening / closing control of the air cutoff valve 51a.

  FIG. 5 shows the raw fuel and reformed fuel during operation of the internal combustion engine 10 when generating power by supplying reformed fuel and auxiliary fuel to the internal combustion engine 10 and burning them in the power generation system according to the present embodiment. Figure 2 shows air and exhaust passages. The fuel cutoff valve 44b opens the raw fuel passage 44 by the control signal transmitted from the control device 70, and the passage switching valve 47a opens the reformed fuel introduction passage 47 and closes the reformed fuel discharge passage 48. doing. The air shut-off valve 51a closes the air introduction passage 51.

  First, the fuel pump 44 a is operated by the control signal transmitted from the control device 70 to the fuel pump 44 a, and the raw fuel stored in the raw fuel tank 31 is supplied to the raw fuel carburetor 32 through the raw fuel passage 44. Is done. The raw fuel supplied to the raw fuel carburetor 32 is vaporized by heat flowing from the internal combustion engine 10 through the heat exchange passages 46a and 46b. The vaporized raw fuel is supplied to the raw fuel inlet of the fuel passage 33b of the reformer 33 through the vaporized raw fuel passage 45, passes through the fuel passage 33b of the reformer 33, and is modified by the above-described chemical reaction. It is reformed to quality fuel. The reformed fuel sent from the reformed fuel outlet of the fuel passage 33b of the reformer 33 passes through the reformed fuel introduction passage 47 and flows into the intake passage 40 '. On the other hand, the air sucked from the air cleaner 30 becomes compressed air by the compressor 35a. A part of the compressed air flows from the air inflow passage 50 into the air reservoir 36 and is used for filling the air reservoir 36. Further, the remaining compressed air is mixed with reformed fuel in the intake passage 40 ′ to become an air-fuel mixture, and the air-fuel mixture is supplied to the intake port 20.

  The air-fuel mixture supplied to the intake port 20 flows into the combustion chamber 17 as the intake valve 18 is opened during the intake stroke. In the compression stroke, as the piston 14 rises, the air-fuel mixture is compressed, and the inside of the combustion chamber 17 becomes high temperature and pressure. Here, when the crank angle sensor 60 detects that the piston 14 has risen to the vicinity of the top dead center, the auxiliary fuel is supplied from the auxiliary fuel supply device 22 into the combustion chamber 17. The supplied secondary fuel is self-ignited in a high-temperature and high-pressure environment, and the generated flame propagates to the reformed fuel and the reformed fuel is burned. As a result of the combustion of the auxiliary fuel and the reformed fuel, the air-fuel mixture in the combustion chamber 17 expands and the piston 14 descends. When the piston 14 moves down to near the bottom dead center, the exhaust valve 19 is opened and the exhaust is discharged from the exhaust port 21.

  The exhaust discharged from the exhaust port 21 passes through the turbine 35 c in the first exhaust passage 41 ′ and then flows into the exhaust inlet of the exhaust passage 33 a of the reformer 33. At this time, the exhaust gas flowing through the first exhaust passage 41 rotates the turbine 35c, and the rotation of the turbine 35c is transmitted to the compressor 35a by the rotating shaft 35b, so that the compressor 35a is driven. The exhaust gas flowing into the exhaust inlet of the exhaust passage 33a of the reformer 33 exchanges heat with the raw fuel in the fuel passage 33b of the reformer 33, and then passes through the exhaust outlet of the exhaust passage 33a of the reformer 33. 2 It flows into the exhaust purification device 34 through the exhaust passage 42 and is purified. The purified exhaust gas is discharged from the purified exhaust outlet of the exhaust purification device 34 to the outside through the third exhaust passage 43.

  FIG. 6 shows passages of raw fuel, reformed fuel, air, and exhaust when the internal combustion engine 10 is stopped. The fuel cutoff valve 44b closes the raw fuel passage 44 by the control signal transmitted from the control device 70, the passage switching valve 47a closes the reformed fuel introduction passage 47, and opens the reformed fuel discharge passage 48. doing. The air shut-off valve 51a opens the air introduction passage 51.

  Since the fuel cutoff valve 44b is closed, the supply of raw fuel from the raw fuel tank 31 to the raw fuel carburetor 32 is stopped. Further, since the air shutoff valve 51 a opens the air introduction passage 51, the compressed air accumulated in the air reservoir 36 flows into the raw fuel carburetor 32 through the air introduction passage 51. The compressed air flows together with the raw fuel remaining in the raw fuel carburetor 32 from the raw fuel carburetor 32 through the vaporized raw fuel passage 45 and into the fuel passage 33b of the reformer 33. In the fuel passage 33 b of the reformer 33, the raw fuel that has flowed together with the compressed air is reformed into reformed fuel, and flows into the exhaust purification device 34 through the reformed fuel discharge passage 48 and the second exhaust passage 42. . The reformed fuel that has flowed into the exhaust purification device 34 together with air is oxidized by the chemical reaction of the thermochemical equation 2 described above, and is discharged to the outside through the third exhaust passage 43.

  With the above configuration, the power generation system according to the present embodiment has the following effects in addition to the effects (1) and (2) exhibited by the first embodiment.

  (4) By introducing air from the raw fuel inlet of the fuel passage 33b of the reformer 33, the raw fuel and reformed fuel remaining in the reformer 33 can be pushed out by the air and discharged. Accordingly, the amount of raw fuel and reformed fuel remaining in the reformer 33 can be reduced, and the air used to push out the raw fuel and reformed fuel remaining in the reformer 33 can be reduced. The raw fuel and the reformed fuel can be oxidized in the exhaust purification device 34.

  (5) Since the compressed air filled in the air reservoir 36 using the turbocharger 35 is used, the blower 49a and the like for introducing air into the reformed fuel discharge passage 48 can be omitted.

<Third Embodiment>
FIG. 7 shows a power generation system according to this embodiment. Similar to the power generation system according to the first embodiment and the power generation system according to the second embodiment, the power generation system is configured to include a fuel supply system, which reforms raw fuel into reformed fuel, This is a system that generates power by using power obtained by burning reformed fuel.

  The power generation system according to the present embodiment is different from the power generation system according to the second embodiment in the introduction destination of the compressed air from the air reservoir 36. That is, a first end of an air introduction passage 51 ′ provided with an air shutoff valve 51a ′ is connected to an air outflow portion of the air reservoir 36, and a second end of the air introduction passage 51 is connected to the reformed fuel discharge. It is connected to the passage 48. The air shut-off valve 51a 'functions as a fourth opening / closing mechanism that opens and closes the air introduction passage 51'.

  FIG. 8 shows the raw fuel and reformed fuel during operation of the internal combustion engine 10 when generating power by supplying the reformed fuel and auxiliary fuel to the internal combustion engine 10 and burning them in the power generation system according to the present embodiment. Figure 2 shows air and exhaust passages. The fuel cutoff valve 44b opens the raw fuel passage 44 by the control signal transmitted from the control device 70, and the passage switching valve 47a opens the reformed fuel introduction passage 47 and closes the reformed fuel discharge passage 48. doing. The air shutoff valve 51a 'closes the air introduction passage 51'.

  First, the fuel pump 44 a is operated by the control signal transmitted from the control device 70 to the fuel pump 44 a, and the raw fuel stored in the raw fuel tank 31 is supplied to the raw fuel carburetor 32 through the raw fuel passage 44. Is done. The raw fuel supplied to the raw fuel carburetor 32 is vaporized by heat flowing from the internal combustion engine 10 through the heat exchange passages 46a and 46b. The vaporized raw fuel is supplied to the raw fuel inlet of the fuel passage 33b of the reformer 33 through the vaporized raw fuel passage 45, passes through the fuel passage 33b of the reformer 33, and is modified by the above-described chemical reaction. It is reformed to quality fuel. The reformed fuel sent from the reformed fuel outlet of the fuel passage 33b of the reformer 33 passes through the reformed fuel introduction passage 47 and flows into the intake passage 40 '. On the other hand, the air sucked from the air cleaner 30 becomes compressed air by the compressor 35a. A part of the compressed air flows from the air inflow passage 50 into the air reservoir 36 and is used for filling the air reservoir 36. Further, the remaining compressed air is mixed with reformed fuel in the intake passage 40 ′ to become an air-fuel mixture, and the air-fuel mixture is supplied to the intake port 20.

  The air-fuel mixture supplied to the intake port 20 flows into the combustion chamber 17 as the intake valve 18 is opened during the intake stroke. In the compression stroke, as the piston 14 rises, the air-fuel mixture is compressed, and the inside of the combustion chamber 17 becomes high temperature and pressure. Here, when the crank angle sensor 60 detects that the piston 14 has risen to the vicinity of the top dead center, the auxiliary fuel is supplied from the auxiliary fuel supply device 22 into the combustion chamber 17. The supplied secondary fuel is self-ignited in a high-temperature and high-pressure environment, and the generated flame propagates to the reformed fuel and the reformed fuel is burned. As a result of the combustion of the auxiliary fuel and the reformed fuel, the air-fuel mixture in the combustion chamber 17 expands and the piston 14 descends. When the piston 14 moves down to near the bottom dead center, the exhaust valve 19 is opened and the exhaust is discharged from the exhaust port 21.

  The exhaust discharged from the exhaust port 21 passes through the turbine 35 c in the first exhaust passage 41 ′ and then flows into the exhaust inlet of the exhaust passage 33 a of the reformer 33. At this time, the exhaust gas flowing through the first exhaust passage 41 rotates the turbine 35c, and the rotation of the turbine 35c is transmitted to the compressor 35a by the rotating shaft 35b, so that the compressor 35a is driven. The exhaust gas flowing into the exhaust inlet of the exhaust passage 33a of the reformer 33 exchanges heat with the raw fuel in the fuel passage 33b of the reformer 33, and then passes through the exhaust outlet of the exhaust passage 33a of the reformer 33. 2 It flows into the exhaust purification device 34 through the exhaust passage 42 and is purified. The purified exhaust gas is discharged from the purified exhaust outlet of the exhaust purification device 34 to the outside through the third exhaust passage 43.

  FIG. 9 shows passages of raw fuel, reformed fuel, air, and exhaust when the internal combustion engine 10 is stopped. The fuel cutoff valve 44b closes the raw fuel passage 44 by the control signal transmitted from the control device 70, the passage switching valve 47a closes the reformed fuel introduction passage 47, and opens the reformed fuel discharge passage 48. doing. The air shut-off valve 51a 'opens the air introduction passage 51'.

  Since the fuel cutoff valve 44b is closed, the supply of raw fuel from the raw fuel tank 31 to the raw fuel carburetor 32 is stopped. However, raw fuel remains in the reformer 33 and heat also remains. Therefore, the reforming reaction continues in the reformer 33, and reformed fuel is generated. The generated reformed fuel flows into the reformed fuel discharge passage 48. On the other hand, since the air shut-off valve 51a 'opens the air introduction passage 51', the compressed air accumulated in the air reservoir 36 flows into the reformed fuel discharge passage 48 through the air introduction passage 51 '.

  The reformed fuel that has joined the air in the reformed fuel discharge passage 48 flows into the exhaust purification device 34 through the second exhaust passage 42. The reformed fuel that has flowed into the exhaust purification device 34 is oxidized by the chemical reaction of the thermochemical equation 2 described above, and is discharged to the outside through the third exhaust passage 43.

  With the above configuration, the power generation system according to the present embodiment has the same effects as the effects (1) and (2) that the first embodiment has, and the same effects as the effect (5) that the second embodiment has. Play.

<Fourth embodiment>
FIG. 10 shows a power generation system according to this embodiment. Similar to the power generation system according to the first embodiment, the power generation system according to the second embodiment, and the power generation system according to the third embodiment, the power generation system is configured to include a fuel supply system. This is a system that generates power using power obtained by reforming into reformed fuel and burning the reformed fuel.

  The power generation system according to this embodiment is different from the power generation system according to the first embodiment in that a heat exchanger 37 is provided in the third exhaust passage 43. The heat exchanger 37 is, for example, a hot water heater, and an exhaust passage and a liquid passage are provided therein so that heat can be exchanged. Exhaust gas flowing from the exhaust purification device 34 into the third exhaust passage 43 passes through the exhaust passage. Pass through and raise the temperature of the water passing through the liquid flow path.

  In the present embodiment, the flow paths of air, raw fuel, and reformed fuel when the internal combustion engine 10 is operating and when the internal combustion engine 10 is stopped are the same flow paths as in the first embodiment.

  By the way, when the amount of heat required for the heat exchanger 37 is increased, for example, when the amount of hot water supply is increased, the amount of heat may be insufficient with only the exhaust heat of the internal combustion engine 10. As described above, the chemical reaction when the reformed fuel is oxidized by the exhaust purification device 34 is an exothermic reaction. Therefore, in this embodiment, when the amount of heat required for the heat exchanger 37 increases, the reformed fuel is supplied to the exhaust purification device 34 without being supplied to the internal combustion engine 10.

  FIG. 11 shows air, raw fuel, and reformed fuel flow paths when the amount of heat required for the heat exchanger 37 is increased in the power generation system according to the present embodiment. The control device 70 controls the opening degree of the fuel cutoff valve 45a and the air cutoff valve 49b based on the exhaust gas temperature measured by the temperature sensor 61 and the required amount of heat. Further, the passage switching valve 47 a closes the reformed fuel introduction passage 47 and opens the reformed fuel discharge passage 48 by a control signal from the control device 70.

  Air sucked from the air cleaner 30 is introduced into the intake port 20 via the intake passage 40 and flows into the combustion chamber 17 as the intake valve 18 is opened. In the combustion chamber 17, the auxiliary fuel supplied from the auxiliary fuel supply device 22 is combusted, thereby generating electric power in the internal combustion engine 10. The exhaust discharged from the exhaust port 21 flows into the reformer 33 through the first exhaust passage 41.

  On the other hand, the raw fuel that has flowed into the reformer 33 is reformed into reformed fuel in the reformer 33 by the heat of the exhaust gas accompanying the combustion of the auxiliary fuel. The reformed fuel passes through the reformed fuel discharge passage 48, merges with the exhaust gas in the second exhaust passage 42, and flows into the exhaust purification device 34.

  A part of the air sucked from the air cleaner 30 also flows into the reformed fuel introduction passage 47 from the connection portion between the intake passage 40 and the reformed fuel introduction passage 47 and flows backward through the reformed fuel introduction passage 47. It flows into the air introduction passage 49. The blower 49 a is driven by a control signal from the control device 70, and air is supplied to the exhaust purification device 34 via the reformed fuel discharge passage 48 and the second exhaust passage 42. In the exhaust purification device 34, the chemical reaction according to the thermochemical equation 2 described above occurs, the reformed fuel is purified, and heat accompanying the chemical reaction is released.

  Then, the exhaust gas flows into the heat exchanger 37 provided in the third exhaust passage 43, performs heat exchange in the heat exchanger 37, and is then discharged from the third exhaust passage 43 to the outside.

  With the configuration described above, the power generation system according to the present embodiment has the following effects in addition to the effects (1) to (3) exhibited by the first embodiment.

  (5) If the reformed fuel is directly introduced into the exhaust purification device 34, the energy generated by the oxidation reaction of the reformed fuel can be used as thermal energy rather than as power for the internal combustion engine 10. Therefore, when the amount of heat required for the heat exchanger 37 is increased as compared with the power required for the internal combustion engine 10, the reformed fuel is introduced into the exhaust gas purification device 34 to be supplied to the heat exchanger 37. The amount of heat generated can be increased.

<Modification>
-In each figure which concerns on said each embodiment, the width | variety of each channel | path is represented typically and does not necessarily show the diameter and flow volume of an actual channel | path.

  In the first, third, and fourth embodiments, the air introduction passages 49 and 51 ′ are connected to the reformed fuel discharge passage 48. However, the connection destination of the air introduction passages 49 and 51 ′ is not limited to the reformed fuel discharge passage 48, and may be connected to the second exhaust passage 42, and a structure in which air directly flows into the exhaust purification device 34. It may be. That is, any structure may be used as long as the reformed fuel and air are mixed when the reformed fuel is discharged.

  In the second embodiment, the air introduction passage 51 is connected to the raw fuel carburetor 32, and the compressed air accumulated in the air reservoir 36 is sent to the raw fuel carburetor 32 when the internal combustion engine 10 is stopped. However, the connection destination of the air introduction passage 51 is not limited to the raw fuel carburetor 32, and may be connected to the vaporization raw fuel passage 45, for example. In this case, the fuel cutoff valve 44b may be provided, for example, as a vaporized raw fuel outlet of the raw fuel carburetor 32. That is, the air introduction passage 51 can be connected to an arbitrary position between the reformer 33 and the raw fuel tank 31, and at that time, the fuel cutoff valve 44 b is more than the connection portion of the air introduction passage 51. What is necessary is just to be provided in the raw fuel tank 31 side.

  In each of the above embodiments, the reformed fuel flow path is switched to the reformed fuel introduction path 47 and the reformed fuel discharge path 48 by the path switching valve 47a. However, the mechanism for switching the flow path of the reformed fuel is not limited to this. For example, each of the reformed fuel introduction passage 47 and the reformed fuel discharge passage 48 is provided with a valve for switching between an open state and a closed state, and the control device 70 controls the open / close state of each valve, thereby reforming. The fuel flow path may be switched.

  -Each valve in each said embodiment should just have a function which can switch at least opening and closing of a channel | path, and the specific structure can be designed arbitrarily.

  -Raw fuel is not limited to methanol. In addition, raw fuel that requires air, water, or the like can be used for reforming. In that case, a configuration may be adopted in which air, water, or the like is supplied to the fuel passage 33b of the reformer 33.

  In each of the above embodiments, in the internal combustion engine 10, the flame generated by burning the auxiliary fuel is propagated to the reformed fuel, and the reformed fuel is burned. However, depending on the reformed fuel to be supplied, the auxiliary fuel supply device 22 may not be provided in the internal combustion engine 10, but an ignition plug may be provided, and the reformed fuel may be burned by the spark generated by the ignition plug.

  The heat exchanger 37 shown in the fourth embodiment may be provided in the power generation system according to the second and third embodiments.

  The position of the fuel shut-off valve 45a in the first and fourth embodiments and the position of the fuel shut-off valve 44b in the third embodiment are not limited to the positions described above, but from the raw fuel tank 31 to the reformer 33. It can be changed to a position where the supply of raw fuel can be stopped.

  In the second and third embodiments, the turbocharger 35 is used to supply air to the internal combustion engine 10 and the air reservoir 36, but the internal combustion engine 10 and air are used using a mechanical supercharger. Air may be supplied to the reservoir 36. In the first and fourth embodiments, air may be supplied to the internal combustion engine 10 using a turbocharger or a mechanical supercharger.

  -In 1st, 4th embodiment, the air blower 49a provided with a ventilation fan is used as a ventilation mechanism, In 2nd, 3rd embodiment, although the air reservoir 36 is used as a ventilation mechanism, Other air blowing mechanisms can also be employed. For example, a positive displacement motor may be provided in the reformed fuel discharge passage 48, and the rotation output may be transmitted to the positive displacement blower to blow air. By doing so, while the reformed fuel is generated by the raw fuel and heat remaining in the reformer 33 and the reformed fuel flows out of the reformer 33, the positive displacement motor is driven to drive the positive displacement blower. The positive displacement motor is stopped when the blowout of the reformed fuel is finished and the blowout from the positive displacement blower is stopped accordingly.

  In the fourth embodiment, the heat exchanger 37 is provided in the third exhaust passage 43, but the position where the heat exchanger 37 is provided is not limited to the third exhaust passage 43. For example, the exhaust purification device 34 may have a heat exchange function.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 33 ... Reformer, 34 ... Exhaust gas purification device, 40 ... Intake passage, 41 ... First exhaust passage, 42 ... Second exhaust passage, 43 ... Third exhaust passage, 47 ... Reformed fuel introduction passage 47a ... passage switching valve, 48 ... reformed fuel discharge passage.

Claims (12)

A reformer (33) provided in an exhaust passage (41, 41 ', 42, 43) of the internal combustion engine (10) for reforming raw fuel into reformed fuel by exhaust heat of the internal combustion engine;
An exhaust purification device (34) provided in an exhaust passage of the internal combustion engine for purifying exhaust of the internal combustion engine;
A reformed fuel introduction passage (47) connected to the reformer and for introducing the reformed fuel into the intake passage (40, 40 ′) of the internal combustion engine;
A reformed fuel discharge passage (48) connected to the reformer and introducing the reformed fuel into the exhaust gas purification device;
A fuel supply system comprising: a first opening / closing mechanism (47a) for opening and closing the reformed fuel discharge passage. A second opening / closing mechanism (47a) for opening and closing the reformed fuel introduction passage;
A fuel passage control device (70) for performing opening / closing control of the first opening / closing mechanism and the second opening / closing mechanism,
The fuel supply system according to claim 1, wherein the fuel passage control device opens the first opening / closing mechanism and closes the second opening / closing mechanism when the internal combustion engine is stopped.   The fuel supply system according to claim 1 or 2, further comprising a third opening / closing mechanism (44b, 45a) for opening / closing a fuel passage for supplying the raw fuel to the reformer. An air introduction passage (49, 51, 51 ′) for introducing air into the reformed fuel discharge passage;
The fuel supply system according to any one of claims 1 to 3, further comprising a fourth opening / closing mechanism (49b, 51a, 51a ') for opening and closing the air introduction passage.   The fuel supply system according to claim 4, wherein the air introduction passage (49, 51 ') introduces air between the reformer and the exhaust purification device.   The fuel supply system according to claim 4, wherein the air introduction passage (51) introduces air into a fuel passage (45) for supplying the raw fuel to the reformer.   The fuel supply system according to any one of claims 4 to 6, wherein a blowing mechanism (36, 49a) is provided in the air introduction passage.   The fuel supply system according to claim 7, wherein the blower mechanism is a blower (49a) that sends out air by rotation of a blower fan.   The fuel supply system according to claim 7, wherein the air blowing mechanism is an air reservoir (36) for storing compressed air. A turbocharger (35) driven by the exhaust gas flowing through the exhaust passage;
The fuel supply system according to claim 9, wherein the turbocharger fills the air reservoir with compressed air. An air passage control device for controlling opening and closing of the fourth opening and closing mechanism;
The air passage control device closes the fourth opening / closing mechanism when the internal combustion engine is operated, and opens the fourth opening / closing mechanism when the internal combustion engine is stopped. Item 11. The fuel supply system according to any one of Items 4 to 10. A heat exchanger (37),
2. The reformed fuel generated by the reformer is introduced into the exhaust gas purification device according to the amount of heat required by the heat exchanger when the internal combustion engine is in operation. The fuel supply system of any one of -11.

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