JP4014124B2 - Fuel evaporator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel evaporation system for raw fuel in a fuel cell system, and more specifically, a plurality of evaporation chambers are connected so as to be able to vent, and a required amount of raw fuel gas is appropriately responsive to a subsequent reactor with good response. The present invention relates to a fuel evaporation device that can be supplied.
[0002]
[Prior art]
The fuel cell system is a power generation system having a fuel cell as a core for generating power by supplying hydrogen as a fuel gas to the hydrogen electrode of the fuel cell and supplying an oxidizing gas containing oxygen to the oxygen electrode of the fuel cell. This fuel cell system directly converts chemical energy into electrical energy, and has recently attracted attention because of its high power generation efficiency and extremely low emission of harmful substances.
[0003]
A fuel evaporation apparatus used in a conventional fuel cell system is described in, for example, Japanese Patent Application No. 11-125366. As shown in FIG. 12, the fuel evaporation apparatus 100 is a high-temperature heat medium generated by burning off-gas (hydrogen-containing gas) generated in a fuel cell by a catalytic reaction in a catalyst combustor (not shown). An inlet 114 for introducing a certain combustion gas HG into the evaporator main body 110, and the combustion gas HG are passed from the top to the bottom inside the U-shaped heat medium tube 112 from the inlet 112a to the outlet 112b. The evaporating chamber 111 for evaporating the raw fuel FL injected from the injector 140 onto the outer surface of the heating medium tube 112 by the heat obtained from the combustion gas HG, and the combustion gas after evaporating the raw fuel FL Combustion gas passage 113 provided adjacent to bottom surface 110A of evaporation chamber 111 through which HG flows and raw fuel gas FG evaporated in evaporation chamber 111 are Main unit from overheating portion 130. which is formed from overheating chamber 132 and the steam tube 131 Metropolitan for superheated by the combustion gases HG passing through the passage 113 is formed.
[0004]
The operation of the conventional fuel evaporation apparatus 100 configured as described above will be described.
Combustion gas HG, which is a high-temperature heat medium generated by burning off gas generated in the fuel cell in a catalyst combustor (not shown), is introduced into the inlet 114 of the evaporator main body 110. The combustion gas HG introduced into the inlet portion 114 passes from the top to the bottom from the inlet portion 112a to the outlet portion 112b in the U-shaped heat medium tube 112 in the evaporation chamber 111. At that time, in the evaporation chamber 111, the combustion gas HG transmits heat to the outer surface of the heat medium tube 112 to evaporate the raw fuel FL injected by the injector 140. Next, the combustion gas HG after evaporating the raw fuel FL is guided to the superheat chamber 132 of the superheater 130 via the combustion gas passage 113, and the raw fuel gas FG evaporated in the evaporation chamber 111 is converted to the raw fuel gas FG. Further heating is performed from the outside of the steam tube 131. The overheated raw fuel gas FG is introduced into a reactor (not shown), and the combustion gas HG after overheating the raw fuel gas FG is discharged out of the system as exhaust gas.
[0005]
The combustion gas HG, which is a heat source of the conventional fuel evaporation apparatus 100, varies depending on the operation state of the fuel cell, and it is necessary to evaporate the raw fuel FL by a necessary amount using the combustion heat of hydrogen and supply it to the reactor. However, due to various factors such as changes in the amount of supplied heat (changes in operating conditions), thermal mass of the fuel evaporation device itself, changes in the ambient air environment temperature, etc., the evaporation state in the evaporation chamber 111 (for example, the occurrence of a liquid pool) There was a problem that the temperature of FG would change.
[0006]
[Problems to be solved by the invention]
The present invention has been made to solve the above-described problems, and controls the amount of raw fuel supplied to the fuel evaporation apparatus, improves the responsiveness of the evaporation rate as compared with the conventional fuel evaporation apparatus, and is appropriate. An object of the present invention is to provide a fuel evaporation device capable of supplying raw fuel gas to a downstream reactor at a gas flow rate.
[0007]
[Means for Solving the Problems]
To solve the above problems Book The gist of the invention is that in a fuel evaporation apparatus having an evaporation chamber for evaporating raw fuel by a high-temperature heat medium to obtain raw fuel gas, the evaporation chamber is formed by connecting a plurality of evaporation chambers so that they can be ventilated in series. The raw fuel injection means for injecting the raw fuel is provided in each of the plurality of evaporation chambers.
[0008]
In this case, the evaporation chamber having the same capacity as the single chamber is divided into a plurality of evaporation chambers rather than the single chamber, and the raw fuel is injected individually according to the evaporation capacity of each evaporation chamber. Since the dead space during injection and uneven injection to the heat transfer tube (heat medium tube) are reduced, the thermal efficiency per unit volume of the evaporation chamber is increased and evaporation is performed instantaneously. Can be supplied quickly.
[0009]
Also Any one of the evaporation chambers is provided with a plurality of the raw fuel injection means. Burning It is a material evaporation device.
[0010]
Particularly in an evaporation chamber having a large heat capacity and a large evaporation capacity, a large amount of raw fuel gas can be quickly supplied by simultaneously injecting a large amount of raw fuel from a plurality of raw fuel injection means provided at the same time (use during acceleration).
[0011]
Also The raw fuel injection control means for selecting any of the raw fuel injection means and injecting the raw fuel in response to a request signal for requesting the raw fuel gas. Burning It is a material evaporation device.
[0012]
According to this configuration, it is possible to determine which / how many evaporation chambers the raw fuel is injected according to the amount of the required raw fuel gas, and to evaporate with the same capacity as the single chamber rather than the single chamber evaporation chamber. Evaporation chamber unit volume because the chamber is divided into multiple evaporation chambers, and by spraying individually according to the evaporation capacity of each evaporation chamber, there is less uneven injection during dead space and heat transfer tubes (heat transfer tubes) Since the heat efficiency per unit is increased and evaporation is performed instantaneously, the necessary amount of raw fuel gas can be supplied quickly.
[0013]
Also The bottom of any one of the evaporation chambers is provided with a heat receiving portion that is provided adjacent to the bottom and receives heat from the heat source means for generating the high-temperature heat medium, and the other evaporation chamber adjacent to the evaporation chamber An inclined portion with the heat receiving portion side down is provided at the bottom of the heat sink. Burning It is a material evaporation device.
[0014]
As a result, the raw fuel stored in the bottom portion without being evaporated in each evaporation chamber is moved to the heat receiving portion that has been quickly moved to the high temperature by the inclined portion, and is evaporated. Therefore, a predetermined amount of raw fuel gas can be obtained with good responsiveness.
[0015]
Also Any of the evaporation chambers has a heat transfer area larger than that of the other evaporation chambers, and the bottom of any of the evaporation chambers is provided with the heat receiving portion. Burning It is a material evaporation device.
[0016]
In the evaporation chamber with a large heat transfer area (more heat medium tubes) and a heat receiving part at the bottom, more heat can be applied, so the raw fuel gas can be obtained instantly and the response The raw fuel gas can be supplied well.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a fuel evaporation apparatus 1 according to the present invention will be described with reference to FIGS. 1 is an overall system diagram of a fuel cell system according to the present invention, FIG. 2 is a plan partial sectional view of a fuel evaporation apparatus according to the present invention, FIG. 3 is a sectional view taken along line AA in FIG. 2 is a cross-sectional view taken along line BB in FIG. 2, FIG. 5 is a cross-sectional view taken along line CC in FIG. 2, and FIG. 6 is a control block diagram of raw fuel injection control means of the fuel evaporation apparatus according to the present invention.
FIG. 7 is a diagram showing the temperature change of the raw fuel gas in the evaporation chamber due to the difference in the raw fuel injection position, and FIG. The figure which shows the target temperature range of fuel gas, FIG.8 (b) is a figure which shows the basic injection pattern of the injector of the fuel evaporation apparatus which concerns on this invention, FIG. 9 is the injection position of the injector of the fuel evaporation apparatus which concerns on this invention 5 is a control flowchart in the case of controlling the temperature of the raw fuel gas by switching the.
FIG. 10 is a control flow chart for ensuring the amount of raw fuel evaporation during acceleration of the vehicle of the fuel evaporation apparatus according to the present invention, and FIG. 11 is the raw material injection control means of the fuel evaporation apparatus according to the present invention. It is a figure which shows the control result of fuel gas temperature.
[0018]
First, the entire fuel cell system FCS according to the present invention will be described with reference to FIG. 1 and FIG.
The fuel cell system FCS mounted on the vehicle is a high-temperature heat medium generated by catalytic combustion of the off-gas OG of the hydrogen electrode of the fuel cell 5 in the catalyst combustor 20 inside the evaporation chamber 11 of the evaporator main body 10. A number of U-shapes that evaporate the raw fuel FL injected from the injectors 41A, 41B, and 41C, which are raw fuel injection means controlled by the raw fuel injection control means 30 on the outer surface of the combustion gas HG. The fuel evaporation device 1 provided with the heat medium tubes 12A, 12B, and 12C, and the raw fuel gas FG generated by evaporating the raw fuel FL in the fuel evaporation device 1 are reacted on the solid catalyst to produce the fuel gas. A reformer 2 which is a reactor to be used, a CO remover 3 for removing carbon monoxide in the fuel gas produced by the reformer 2, and a fuel gas supplied from the CO remover 3 A fuel cell 5 that generates electricity by reacting hydrogen with oxygen in the air compressed by an air compressor 4 that is an oxidant supply means, and a gas that separates and removes moisture from the off-gas OG at the hydrogen electrode of the fuel cell 5. The liquid separator 6 and the hydrogen gas off-gas OG and auxiliary fuel supplied from the gas-liquid separator 6 are combusted to generate combustion gas HG, which is a high-temperature heat medium that becomes a heating source of the fuel evaporation device 1 at the time of start-up And a combustion burner 7 having an auxiliary fuel (not shown) supply line (not shown).
[0019]
The operation of the fuel cell system FCS configured as described above will be described.
A predetermined amount of raw fuel FL (for example, a mixed fuel of methanol and water) is supplied from the raw fuel storage tank T to the fuel evaporation device 1 by a pump. The raw fuel FL supplied to the evaporator main body 10 of the fuel evaporator 1 is supplied to the evaporator main body 10 by injectors 41A1, 41A2, 41A3, 41B, 41C which are raw fuel injection means controlled by the raw fuel injection control means 30. Injected onto the outer surfaces of a number of U-shaped heat medium tubes 12A, 12B, 12C provided in the evaporation chamber 11. A combustion gas HG generated by burning off-gas OG at the hydrogen electrode of the fuel cell 5 flows in the heating medium tubes 12A, 12B, and 12C in the evaporation chamber 11, and the raw fuel FL is transferred to the heating medium. It evaporates as raw fuel gas FG in the evaporation chamber 11 by heat obtained from the combustion gas HG through the tubes 12A, 12B, and 12C. As a heating source of the evaporation apparatus main body 10, during operation, the catalytic combustor 20 uses off-gas OG at the hydrogen electrode of the fuel cell 5 and combustion gas HG generated by catalytic combustion of auxiliary fuel. When there is no heating source, auxiliary fuel (for example, methanol) is burned by the combustion burner 7 so that the necessary amount of heat can be secured. On the contrary, when the heating source becomes excessive, the combustion gas HG can be bypassed immediately after the catalytic combustor 20 and partially exhausted to the outside.
The details of the raw fuel injection control means 30 for controlling the injection amount of the raw fuel FL and the injection positions of the injectors 41A, 41B, 41C of the fuel evaporator 1 will be described later.
[0020]
The raw fuel gas FG generated in the evaporator main body 10 is introduced into the reformer 2, and the raw fuel gas FG introduced into the reformer 2 reacts on a solid catalyst (for example, a Cu—Zn-based catalyst). To produce hydrogen-rich fuel gas. Further, the hydrogen-rich fuel gas generated in the reformer 2 is oxidized with hydrogen in the fuel gas supplied from the CO remover 3 after carbon monoxide in the gas is removed by the CO remover 3. It is introduced into a fuel cell 5 that generates electricity by reacting with oxygen in the air compressed by an air compressor 4 that is an agent supply means. The off-gas OG at the hydrogen electrode of the fuel cell 5 is separated and removed by the gas-liquid separator 6 and then burned again by the catalytic combustor 20 to become a heating source for the evaporator main body 10.
[0021]
Hereinafter, a characteristic configuration of the fuel evaporation apparatus 1 according to the present invention will be described in detail with reference to FIGS. 1 to 11.
As shown in FIG. 3 to FIG.
In each of the evaporation chambers 11A, 11B, and 11C, the heat medium tubes 12A, 12B, and 12C and tube holding portions 12Aa, 12Ba, and 12Ca that hold both ends of the heat medium tube are disposed, and these three evaporation chambers 11A are disposed. , 11B, 11C connected in series so as to be able to ventilate, and an evaporation chamber main body 10 composed of combustion gas passages P1 to P11 routed around the evaporation chamber 11,
A raw fuel injection device 40 formed of a raw fuel supply pipe 42 for supplying the raw fuel FL to the evaporation chamber 11 and injectors 41A, 41B, 41C which are raw fuel injection means provided below the raw fuel supply pipe 42; ,
A catalytic combustor 20 which is a heat source means provided in the lower part of the evaporation chamber 11A and which generates combustion gas HG that is a high-temperature heat medium serving as a heat source of the evaporation chamber 11;
A raw fuel injection control means 30 for receiving a request signal for the raw fuel gas FG, selecting one of the injectors 41A, 41B, 41C, and controlling to inject a predetermined amount of raw fuel FL from the selected injector;
The main part consists of
[0022]
The evaporator main body 10 includes an evaporation chamber 11 and combustion gas passages P1 to P11 routed around the evaporation chamber 11.
As shown in FIG. 3, the evaporation chamber 11 has the largest evaporation capability (the largest number of heat medium tubes 12A), the first evaporation chamber 11A, and the second largest evaporation capability (of the heat medium tube 12B). The second evaporating chamber 11B has the second largest number), and the third evaporating chamber 11C has the smallest evaporating capacity (the smallest number of heat medium tubes 12C). It is a box-type room that is connected in series so that the area of the boundary surface between them is substantially the same, so that air can pass through in series.
The order in which the evaporation chambers 11 are connected in series is not particularly limited. For example, the first evaporation chamber 11A may be disposed at an intermediate position between the second evaporation chamber 11B and the third evaporation chamber 11C.
In the evaporation chamber 11, a predetermined amount of raw fuel FL from the injector whose injection amount and injection position are selected by the raw fuel injection control means 30 in accordance with the evaporation capacity of each of the evaporation chambers 11 A, 11 B, and 11 C is removed from the heat medium tube. Sprayed on the surface. The direction in which the injectors 41A, 41B, 41C inject the raw fuel FL is on the inlet side (the side into which the combustion gas HG enters) of the heat medium tubes 12A, 12B, 12C provided in the respective evaporation chambers 11A, 11B, 11C. It is jetted toward.
In this way, the evaporation chamber having the same capacity as the single chamber is divided into a plurality of evaporation chambers rather than the single chamber, and the raw fuel FL is injected individually according to the evaporation capacity of each evaporation chamber. As a result, the dead space at the time of injection and the injection unevenness to the heat transfer tube as the heat transfer tube are reduced, so that the thermal efficiency per unit volume of the evaporation chamber is increased. As a result, since evaporation is performed instantaneously, the necessary amount of raw fuel gas can be quickly supplied when necessary.
[0023]
The raw fuel injection device 40 is provided in the upper part of the evaporation chamber 11, and as shown in FIG. 3, the raw fuel supply pipe 42, which is a manifold pipe for supplying the raw fuel FL to the injectors 41A, 41B, 41C, and each evaporation chamber 11A. , 11B, 11C, and an injector 41A that injects the raw fuel FL by suitably controlling the injection amount and injection position of the raw fuel FL supplied from the raw fuel supply pipe 42 by the raw fuel injection control means 30. , 41B, 41C.
The injectors 41A, 41B, and 41C are single fluid nozzles, and the flow rate is controlled by the nozzle back pressure. As shown in FIG. 2, there are three (41A) on the upper rear side of the first evaporation chamber 11A having the largest evaporation capability (the largest number of heat medium tubes 12A). ₁ , 41A ₂ , 41A _Three ) The second evaporating capacity is the second largest (the number of the heat medium tubes 12B is the second largest) and the second evaporating capacity is the smallest (the number of the heat medium tubes 12C is the smallest). One (41B and 41C) is provided on the upper front side of the evaporation chamber 11C.
In this way, a large amount of raw fuel gas is quickly supplied by injecting a large amount of raw fuel simultaneously from a plurality of injectors, which are raw fuel injection means, particularly in an evaporation chamber having a large heat capacity and a large evaporation capacity. Yes (use during acceleration). Therefore, even if there is a sudden large load request, it is possible to respond sufficiently.
[0024]
In each of the evaporation chambers 11A, 11B, and 11C, the combustion gas HG, which is a high-temperature heat medium generated from the catalytic combustor 20, is passed through the interior, and a large amount of heat that evaporates the raw fuel FL that contacts the outer surface thereof. Medium tubes 12A, 12B, and 12C are provided respectively.
As shown in FIGS. 4 and 5, these heat medium tubes 12 </ b> A, 12 </ b> B, 12 </ b> C have an inclined portion in which at least a part of the upper piping is inclined downward toward the tube holding portions 12 </ b> Aa, 12 </ b> Ba, 12 </ b> Ca. It has a formed U shape.
Moreover, tube holding | maintenance part 12Aa, 12Ba, 12Ca which hold | maintains the both ends of these heat-medium tube 12A, 12B, 12C is provided. By forming in this way, the droplets of the raw fuel FL adhering to the upper part of the heat medium tube are preferably moved from the catalyst combustor 20 toward the tube holding portions 12Aa, 12Ba, and 12Ca that are heated by heat conduction. Can be evaporated. Further, by providing the tube holding portions 12Aa, 12Ba, and 12Ca as wall portions, the combustion gas HG and the raw fuel gas FG can be prevented from being mixed in the respective evaporation chambers 11A, 11B, and 11C. Furthermore, the pipes in the evaporation chambers 11A, 11B, and 11C of the heat medium tubes 12A, 12B, and 12C are arranged so that the top is rough and the bottom is dense. By doing so, the thermal mass at the bottom of each of the evaporation chambers 11A, 11B, and 11C is increased to make it difficult for a liquid pool to occur.
The piping diameters of the heat medium tubes 12A, 12B, and 12C are the same for all the heating medium tubes 12A, 12B, and 12C.
[0025]
Further, a partition plate 11P is provided between the first evaporation chamber 11A and the second evaporation chamber 11B as shown in FIG. The partition plate 11P is provided with an upper opening provided in the upper part at the same height as the thickness of the upper tube group of the heat medium tube 12A, and a lower opening between the bottom plate 11b as a heat receiving part and the partition plate 11P. ing. The lower opening is partially or entirely open at the joint. As for the cross-sectional shape of the partition plate 11P, the upper side has a rectangular shape with the upper opening interposed therebetween, and the lower side has an inverted Y shape. A similar partition plate 11P is also provided between the second evaporation chamber 12B and the third evaporation chamber 12C.
[0026]
Further, a large number of heat medium tubes 12A are disposed therein, and the catalyst combustor 20 is adjacent to the bottom thereof, so that the evaporation chamber 11A is disposed above the first evaporation chamber 11A having the largest evaporation capability. Three injectors 41A for injecting raw fuel FL into ₁ , 41A ₂ , 41A _Three In addition, in order to be able to mix and supply the amount of air (AIR) required for the reforming reaction of the reformer 2 which is a subsequent stage reactor with the raw fuel gas FG, air (AIR) as shown in FIG. ) An inlet 15 is provided. The air (AIR) inlet 15 is preferably provided in an evaporation chamber having a large heat capacity and the largest evaporation capacity.
In this way, when the raw fuel gas FG moves in each of the evaporation chambers 11A, 11B, and 11C toward the outlet side of the evaporation chamber body 10, it is provided in each of the evaporation chambers 11A, 11B, and 11C. Since the air (AIR) and the raw fuel gas FG can be completely mixed by colliding with the heat medium tubes 12A, 12B, 12C and the partition plate 11P, the reformer 2 which is a subsequent reactor is uniformly mixed. A raw fuel gas FG having a composition can be introduced.
[0027]
In addition, a bottom plate 11b as a heat receiving portion is in close contact with the ceiling plate 20t of the catalytic combustor 20 as a heat source means as shown in FIGS. 3 and 4 at the bottom of the first evaporation chamber 11A having the largest evaporation capability. Is provided. By providing the bottom plate 11b in close contact with the ceiling plate 20t, heat from the catalyst combustor 20 can be reliably transmitted to the evaporation chamber 11A. Further, by increasing the amount of combustion gas in the catalyst combustor 20, the evaporation chamber 11A can always supply the necessary amount of heat.
The catalytic combustor 20 may be provided at the bottom of another evaporator.
As described above, one of the evaporation chambers has a heat transfer area larger than that of the other evaporation chambers (a larger number of heat medium tubes), and the bottom of the evaporation chamber is provided with a bottom plate that is a heat receiving portion. Thus, raw fuel gas can be obtained instantaneously by giving a large amount of heat to the evaporation chamber having a large heat transfer area.
[0028]
Further, the bottom plate 11b of the second evaporation chamber 11B and the third evaporation chamber 11C is a single plate connected to the bottom plate 11b of the first evaporation chamber 11A. As shown in FIG. An inclined portion with the 11A side down is formed.
As described above, the catalyst combustor 20 that is a heat source means for generating the combustion gas HG that is a high-temperature heat medium provided adjacent to the bottom of any evaporation chamber is provided, and the heat receiving unit that receives the heat of the catalyst combustor 20. The bottom plate of the other evaporation chamber adjacent to the evaporation chamber is provided with an inclined portion with the heat receiving portion side down, so that the original material stored in the bottom portion without being evaporated in each evaporation chamber is provided. The fuel FL is collected by the heat receiving part which is moved by the inclined part and quickly becomes high temperature, and is evaporated. Therefore, a predetermined amount of raw fuel gas can be obtained with good responsiveness.
[0029]
As shown in FIGS. 3 and 4, the catalytic combustor 20 has a rectangular cross-sectional shape and is provided adjacent to the bottom of the evaporation chamber 11 </ b> A.
The catalytic combustor 20 is generated by burning an off-gas OG, an inlet portion 21 for introducing an off-gas OG of the hydrogen electrode of the fuel cell 5 as a combusted body, a catalyst layer 22 for burning the off-gas OG by a combustion reaction, and the like. And an outlet 23 having a partition plate 24 in which the flow direction of the combustion gas HG, which is a high-temperature heat medium, can be changed by 180 degrees. The partition plate 24 also serves as a partition plate that prevents the combustion gas HG at the outlet side of the evaporation chamber 11 </ b> A from mixing with the combustion gas HG at the outlet portion 24 of the catalytic combustor 20.
[0030]
Further, around each of the evaporation chambers 11A, 11B, and 11C, combustion gas passages P1 to P11 through which the combustion gas HG exiting from each of the evaporation chambers 11A, 11B, and 11C flows are formed. By providing the combustion gas passages P1 to P11, the temperature in the evaporation chamber can be kept and heated, so that the raw fuel FL can be more suitably evaporated.
[0031]
Next, the operation of the fuel evaporation apparatus 1 according to the present invention will be described with reference to FIGS.
As shown in FIG. 4, the off-gas OG at the hydrogen electrode of the fuel cell 5, which is a combusted body, passes through the inlet portion 21 of the fuel evaporation device 1 to the catalyst layer 22 that performs the combustion reaction of the catalytic combustor 20 as it is. The off-gas OG is combusted to generate a combustion gas HG that is a high-temperature heat medium, and is discharged to the combustion gas passage P1 that is the base end. The generated high-temperature combustion gas HG flows from bottom to top in a U-shaped heat medium tube 12A (combustion gas passage P2) provided in the evaporation chamber 11A. When the combustion gas HG passes through the U-shaped heat medium tube 12A in the evaporation chamber 11A, the raw fuel FL injected by the injector 41A to the outer surface of the heat medium tube 12A is evaporated, and the raw fuel gas FG is generated.
[0032]
Next, the combustion gas HG after evaporating the raw fuel FL becomes the outlet 12A of the heat medium tube 12A. _OUT As shown in FIG. 2, combustion gas passages P3 (front side of the evaporation chamber 11A) and P4 (left side of the front of the evaporation chamber 11A) provided so as to surround the evaporation chamber 11A are provided. It flows and reaches the combustion gas passage P6 via the combustion gas passage P5 (rear side of the evaporation chamber 11A). Further, as shown in FIG. 5, the combustion gas HG which is a high-temperature heat medium branches into two from the combustion gas passage P6 and flows in the heat medium tubes 12B and 12C (combustion gas passages P7 and P8) from the top to the bottom. The combustion gas passage P10 provided at the bottom of the evaporation chambers 11B and 11C and the evaporation chambers 11B and 11C through the combustion gas passage P9 on the lower side of the evaporation chambers 11B and 11C when viewed from the front (side). It is discharged to the outside as exhaust gas through the combustion gas passage P11 at the end of the side portion. In addition, the effect | action here demonstrated the effect | action when the injection | throwing-in of a standard injection pattern is performed with the injector 41A in the evaporation chamber 11A by the raw fuel injection control means 30 mentioned later.
[0033]
On the other hand, the raw fuel gas FG evaporated in the first evaporation chamber 11A passes through the opening of the partition plate 11P in series to the second evaporation chamber 11B and the third evaporation chamber 11C as shown in FIG. It is introduced and introduced into the reformer 2, which is a subsequent reactor.
[0034]
Next, the raw fuel injection control means 30 for controlling the injection amount and the injection position of the raw fuel FL of the injectors 41A, 41B, 41C which are the raw fuel injection means of the fuel evaporation apparatus 1 according to the present invention will be described. Here, the raw fuel injection control means 30 of the fuel evaporation apparatus 1 when the fuel cell system FCS is mounted on a vehicle will be described.
The idling here refers to the operation of the auxiliary equipment (compressor, heater, air conditioner, etc.) of the fuel cell 5 even if the fuel cell 5 does not require the amount of the raw fuel gas FG. In order to cover the electric power necessary for maintaining, the fuel evaporation device 1 is generating a small amount of raw fuel gas FG.
In addition, the low load state refers to a constant depressing state where the accelerator opening is small, and refers to a state where the required amount of the raw fuel gas FG is larger than that during idling.
Further, the accelerator fully open (WOT) refers to a state where the required amount of raw fuel gas is the maximum when the accelerator opening is the maximum.
[0035]
Initially, the attachment position of the temperature sensor currently attached to the fuel evaporation apparatus 1 is demonstrated.
As shown in FIGS. 3 to 5, three temperature sensors for the combustion gas HG and three temperature sensors for the raw fuel gas FG are attached.
T _gin The combustion gas temperature at the outlet of the catalyst combustor (the gas temperature at the inlet of the first evaporation chamber 11A)
T _g1 The combustion gas temperature at the outlet of the first evaporation chamber 11A
T _g2 The combustion gas temperatures at the inlets of the second evaporation chamber 11B and the third evaporation chamber 11C
T _V1 The raw fuel gas temperature at the outlet of the first evaporation chamber 11A
T _V2 The raw fuel gas temperature at the outlet of the second evaporation chamber 11B
T _V3 The raw fuel gas temperature at the outlet of the third evaporation chamber 11C
It is.
The raw fuel injection control means 30 is a control for selecting an injector for injecting the raw fuel FL and controlling the injection amount based on the above temperature measurement data, a stack operating state signal required from the fuel cell body, and an accelerator opening signal. Means. FIG. 6 shows a control block diagram of the raw fuel injection control means 30.
[0036]
Next, how the temperature of the raw fuel gas FG obtained by the raw fuel injection position of the injector changes depending on the load will be described with reference to FIG. FIG. 7 shows the results of a test conducted using a separate test apparatus to determine how raw fuel gas in a suitable temperature range can be obtained by injecting raw fuel into the evaporation chamber. As a test method, three injectors A, B, and C are provided at the uppermost part of the evaporation chamber of a single chamber provided with a heat medium tube from the innermost side by changing the distance from the outlet side of the evaporation chamber. Thus, the temperature of the raw fuel gas at the evaporating chamber outlet when the same injection amount is injected for each injector is measured.
As shown in FIG. 7, when the raw fuel was injected from the injector A located at the back of the evaporation chamber with reference to the outlet of the evaporation chamber, the temperature of the raw fuel gas was highest at both idling and low load. . Further, when the raw fuel was injected from the injector C closest to the outlet of the evaporation chamber, the temperature of the raw fuel gas was the lowest at the time of idling and low load (the injection amount was the same). When the raw fuel was injected from the injector B located at the center of the injectors A and C, the temperature of the raw fuel gas was intermediate between the injectors A and C (the injection amount was the same).
[0037]
Therefore, in the case of a fuel evaporation apparatus in which the evaporation chambers are connected so as to be able to ventilate in series and each of the evaporation chambers is provided with raw fuel injection means, the position of the injector for injecting the raw fuel is switched and the depth of the evaporation chamber is changed. By injecting the raw fuel from, the temperature of the raw fuel gas at the evaporating chamber outlet can be increased. On the other hand, the temperature of the raw fuel gas at the evaporating chamber outlet can be lowered by injecting the raw fuel from the near side near the evaporating chamber outlet.
[0038]
Based on the test results of the raw fuel gas temperature at these injection positions, the control is performed as follows.
With reference to FIG. 8, how to determine the basic injection pattern (S3) of FIG. 9 will be described.
(1) First, a temperature threshold T to be controlled so that the temperature of the raw fuel gas FG with respect to the operation output of the fuel cell falls within the target temperature range shown in FIG. _vhigh And T _vlow Set.
Here, T in FIG. _vhigh Is the upper limit of the target temperature range, T _vlow Is the lower limit of the target temperature range. T _vmax Is the upper limit of the allowable temperature range, T _vmin Is the lower limit of the allowable temperature range.
(2) Next, using the basic injection pattern shown in FIG. 8 (b), the injection amount of the raw fuel FL is calculated from the operation request output of the fuel cell 5, and which injector is used to inject the raw fuel FL. Decide.
As shown in FIG. 8B, when the fuel cell 5 is idling (idle), the basic injection pattern is the injector 41A. _Three Is used. In addition, the two injectors 41A at low load when the required output increases. ₂ , 41A _Three Inject with. When the required output further increases, the two injectors 41A ₂ , 41A _Three Two injectors 41A having a larger injection amount than the combination of ₁ , 41A _Three Switch to the combination. As in the case where the accelerator opening is fully open (WOT), the place where the maximum output is required is three injectors 41A. ₁ , 41A ₂ , 41A _Three It comes to inject with. On the other hand, the injectors 41B and 41C are always in a stopped state. By doing so, the evaporation chambers 11B and 11C on the downstream side are always in an empty state, so that the temperature of the raw fuel gas FG at the outlet of the evaporation chamber 11 is suitably controlled by switching the injection position of the injector. can do.
In this way, it is required by receiving the request signal for requesting the raw fuel gas FG, selecting any one of the raw fuel injection means, and providing the raw fuel injection control means 30 for injecting the raw fuel FL. It is possible to determine which / how many evaporation chambers the raw fuel is injected according to the amount of the raw fuel gas FG, and the evaporation chamber having the same capacity as the single chamber rather than the single chamber evaporation chamber. By individually injecting into the chamber, there is less injection unevenness with respect to dead space and heat transfer tubes (heat medium tubes) at the time of injection, so that the thermal efficiency per unit volume of the evaporation chamber increases. As a result, since evaporation is performed instantaneously, a necessary amount of raw fuel gas can be quickly supplied. Therefore, even if there is a sudden load request, it is possible to cope with it sufficiently.
[0039]
Next, referring to FIG. 9, an injector 41 </ b> A (41 </ b> A) that is a raw fuel injection means in the evaporation chamber 11. ₁ , 41A ₂ , 41A _Three ), The control flow of the raw fuel injection control means 30 when the temperature of the raw fuel gas FG is controlled by switching the injection positions of 41B and 41C.
1. It is determined whether or not the fuel evaporation device 1 is in a warm-up operation (S1).
If the warm-up operation is being performed, the warm-up operation subroutine is entered (S17) and the warm-up operation is maintained.
2. If the engine is not warming up, the throttle opening increment (Δθ _th ) Is confirmed (S2).
Throttle opening increment (Δθ _th ), The acceleration subroutine is entered (S18) and the acceleration state is maintained.
3. Throttle opening increment (Δθ _th When the steady operation is not performed, the reference injection pattern shown in FIG. 8B is read from the table (S3). That is, 41A is selected as the injector to be injected. A map showing the relationship between the injector injection time Ti and the raw fuel injection amount Q is read (S4). Actually required injection time Ti is calculated from various correction terms (correction terms based on battery voltage or the like) (S5). The raw fuel FL is intermittently injected while the injection time Ti is pulse-controlled by the selected injector 41A (S6).
4). Raw fuel gas temperature T at the outlet of the third evaporation chamber 11C after injection _V3 And temperature threshold T on the high temperature side _Vhigh Are compared (S7).
5). Raw fuel gas temperature T at the outlet of the third evaporation chamber 11C after injection _V3 Is the temperature threshold T on the high temperature side _Vhigh If it exceeds, it is processed as follows.
(A) The measured raw fuel gas temperature T _V1 , T _V2 , T _V3 To ΔT on the raw fuel gas FG side _V Is calculated (S8).
(B) Measured combustion gas temperature T _gin , T _g1 , T _g2 To the combustion gas HG side temperature gradient ΔT _g Is calculated (S9).
(C) ΔT _V -The injection pattern table is read (S10).
(D) ΔT _V -The injection position of the injector 41A is switched based on the injection pattern (S11).
As a specific example, 41A ₁ , 41A ₂ , 41A _Three T _V3 > T _Vhigh 41A ₁ ΔT so that the injection position is switched from to 41C _V -A table of injection patterns is provided. By this series of processing, the temperature T of the raw fuel gas FG _V3 Can be lowered within the target temperature range.
Thereafter, the process returns to S1.
6). Raw fuel gas temperature T at the outlet of the third evaporation chamber 11C after the raw fuel FL is injected in S6 _V3 Is the temperature threshold T on the high temperature side _Vhigh In the following cases, the raw fuel gas temperature T at the outlet of the third evaporation chamber 11C is further increased. _V3 Is the temperature threshold T on the low temperature side _Vlow (S12).
Raw fuel gas temperature T _V3 Is the temperature threshold T on the low temperature side _Vlow In the following cases, the process returns to S1.
Raw fuel gas temperature T _V3 Is the temperature threshold T on the low temperature side _Vlow If it exceeds, it is processed as follows.
(E) Measured raw fuel gas temperature T _V1 , T _V2 , T _V3 To ΔT on the raw fuel gas FG side _V Is calculated (S13).
(F) Measured combustion gas temperature T _gin , T _g1 , T _g2 To the combustion gas HG side temperature gradient ΔT _g Is calculated (S14).
(G) ΔT _V -The injection pattern table is read (S15).
(H) ΔT _V -The injection position of the injector 41A is switched based on the injection pattern (S16).
As a specific example, 41A _Three T _V3 <T _Vlow Then, the injector 41A _Three To 41A ₁ ΔT to switch the injection position to _V -A table of injection patterns is provided. By this series of processing, the temperature T of the raw fuel gas FG _V3 Can be raised within the target temperature range.
Thereafter, the process returns to S1.
Thus, based on the reference injection pattern, the outlet gas temperature T of the raw fuel gas FG in the third evaporation chamber 11C when the raw fuel FL is injected by the injector. _V3 Measured raw fuel gas temperature T in order to make the target temperature range _V1 , T _V2 , T _V3 And combustion gas temperature T _gin , T _g1 , T _g2 Temperature gradient ΔT _g And ΔT _V And the value is calculated as ΔT _V -A new injector can be selected for injection by comparing with the values in the injection pattern table. As a result, the required raw fuel gas can be supplied in an appropriate amount to the reformer 2 which is a subsequent reactor with good response. Further, since the temperature controllability of the raw fuel gas FG has been improved, the heating unit that has been provided on the outlet side of the conventional fuel evaporation apparatus is not necessary.
[0040]
Next, the control flow of the raw fuel injection control means 30 that performs control so as to ensure the amount of raw fuel evaporation during vehicle acceleration will be described with reference to FIG.
7). Throttle opening increment (Δθ _th ) Is measured to check whether there is an increase in the opening (S21).
Throttle opening increment (Δθ _th ), The steady operation routine is entered (S38) and the current operation state is maintained.
8). Throttle opening increment (Δθ _th ), The throttle opening increment (Δθ compared to the acceleration threshold k) _th ) Is intermediate acceleration or full-open acceleration (S22).
9. Throttle opening increment (Δθ _th ) Exceeds the threshold value k, that is, when the vehicle is at intermediate acceleration or full acceleration, the injector 41A (41A) ₁ , 41A ₂ , 41A _Three ) It is determined whether the drive status of 41B and 41C is stopped (S23).
(A) Injecting fuel injector 41A calculates the raw fuel injection amount as the actually required injection time Ti from various correction terms (correction terms based on battery voltage, etc.) in order to enter the driving state (S27). Next, the injector increase map 3 is read (S28). The injector 41A that is not driven is operated to inject the raw fuel FL. The raw fuel FL is intermittently injected while the injection time Ti is pulse-controlled (S29).
By injecting the injector that opposes the heat transfer surface that is not injected with the raw fuel FL in this way, the generation of the amount of the raw fuel gas corresponding to the acceleration increase can be compensated with good responsiveness.
(B) During operation, the injector 41A injects an increased amount of fuel, so that the incremental raw fuel injection amount is calculated as an actually required injection time (addition time) Ti from various correction terms (correction terms based on battery voltage or the like) (S24). ). Next, the injector increase map 2 is read (S25). The raw fuel FL is intermittently injected while the injection time Ti is pulse-controlled (S26).
(C) As a result of the injection of the raw fuel FL in S26 and S29, the combustion gas temperature T at the inlets of the second evaporation chamber 11B and the third evaporation chamber 11C _g2 Is the temperature threshold T on the low temperature side _glow If it exceeds, the process returns to S27.
(D) Combustion gas temperature T at the inlet of the second evaporation chamber 11B and the third evaporation chamber 11C _g2 Is the temperature threshold T on the low temperature side _glow In the following cases, the operation of the injector 41B and the injector 41C is stopped (S31), and the injector 41A (41A ₁ , 41A ₂ 41A _Three ) Is increased (S32).
Thereby, even if the temperature of the combustion gas HG decreases, it is possible to secure the amount of the raw fuel gas FG generated and maintain the temperature of the raw fuel gas FG. Thereafter, the process returns to S21.
10. Throttle opening increment (Δθ _th ) Is less than or equal to the acceleration threshold k, that is, when the acceleration request of the vehicle is weak, the injector 41A (41A ₁ , 41A ₂ 41A _Three ) It is determined whether or not the operating conditions of 41B and 41C are in operation (S33).
The stopped injector 41A maintains the stopped state as it is (S37). Thereafter, the process returns to S21.
The injector 41A in operation calculates the incremental raw fuel injection amount as an actually required injection time Ti from various correction terms (correction terms based on battery voltage or the like). Next, the injector increase map 1 is read (S35). The raw fuel FL is intermittently injected while the injection time Ti is pulse-controlled based on the calculated value and the injector increase map 1 (S36). By processing in this way, it is possible to meet the demand for increasing the raw fuel gas FG with respect to slight acceleration of the vehicle. Return to S21.
In this way, it is determined whether or not the vehicle is accelerating from the increment of the throttle opening, and the temperature of the raw fuel gas FG is controlled by controlling the injection amount of the raw fuel FL and the injection position of the injector according to the operating condition of the injector. The necessary amount of the raw fuel gas FG during acceleration can be reliably ensured without adjustment.
[0041]
Next, the control result of the raw fuel gas temperature by the raw fuel injection means 30 is shown in FIG. Conventionally, when the operating output of the fuel cell 5 is high, if the temperature of the raw fuel gas FG is set to a suitable temperature range as indicated by the parallel broken lines, the operating output of the fuel cell 5 is low. In the case of time or medium load, there is a problem that the temperature is shifted to a high temperature side exceeding a suitable temperature range as shown in FIG. According to the raw fuel injection control means 30 of the present invention, as shown in the embodiments so far, the operating output of the fuel cell 5 is supplied to the raw fuel gas FG over a wide range from a low load to a high load. Can be controlled.
[0042]
【The invention's effect】
As is apparent from the above configuration and operation, according to the present invention,
(1) An appropriate amount of raw fuel gas can be supplied to the reactor stably in an appropriate temperature range against fluctuations in the evaporation heat source in various operation modes, environments, and the like.
(2) At the time of the acceleration signal, the supply of the evaporation heat source accompanying the increase in the amount of raw fuel gas required for the fuel evaporation device is delayed, so that the raw fuel is injected in the operation mode using the thermal mass effect of the evaporation device. By injecting an injector that is opposed to the heat transfer surface that is not in operation (air-spreading state), the generation of the raw fuel gas amount corresponding to the acceleration increase can be compensated with good responsiveness.
Therefore, the raw fuel gas can be supplied to the reactor with good responsiveness in response to a request for acceleration of the vehicle.
[Brief description of the drawings]
FIG. 1 is an overall system diagram of a fuel cell system according to the present invention.
FIG. 2 is a plan partial sectional view of a fuel evaporation apparatus according to the present invention.
3 is a cross-sectional view taken along the line AA in FIG.
4 is a cross-sectional view taken along the line BB in FIG.
FIG. 5 is a cross-sectional view taken along the line CC of FIG.
FIG. 6 is a control block diagram of raw fuel injection control means of the fuel evaporation apparatus according to the present invention.
FIG. 7 is a view showing a temperature change of raw fuel gas in the evaporation chamber due to a difference in raw fuel injection position.
8A is a diagram showing a target temperature range of raw fuel gas with respect to an operation output of a fuel cell of a fuel evaporation apparatus according to the present invention. FIG.
(B) It is a figure which shows the basic injection pattern of the injector of the fuel evaporation apparatus which concerns on this invention.
FIG. 9 is a control flowchart for controlling the temperature of the raw fuel gas by switching the injection position of the injector of the fuel evaporation apparatus according to the present invention.
FIG. 10 is a control flowchart for securing the amount of raw fuel evaporation during acceleration of the vehicle of the fuel evaporation apparatus according to the present invention.
FIG. 11 is a diagram showing a control result of the raw fuel gas temperature by the raw fuel injection control means of the fuel evaporation apparatus according to the present invention.
FIG. 12 is a front sectional view of a conventional fuel evaporation apparatus.
[Explanation of symbols]
1 Fuel evaporation system
10 Evaporator body
11 Evaporation chamber
11b Bottom plate (heat receiving part)
12A, 12B, 12C Heat transfer tube
P1-P11 Combustion gas passage
20 catalytic combustor (heat source means)
30 Raw fuel injection control means
40 Raw fuel injection device
41A, 41B, 41C Injector
FG raw fuel gas
HG combustion gas (high temperature heat medium)

Claims (4)

In a fuel evaporation apparatus provided with an evaporation chamber for evaporating raw fuel with a high-temperature heat medium to obtain raw fuel gas,
The evaporation chamber is composed of a plurality of evaporation chambers connected in series so as to allow ventilation.
Raw fuel injection means for injecting the raw fuel is provided in each of the plurality of evaporation chambers ,
A bottom portion of any one of the evaporation chambers is provided with a heat receiving portion that is provided adjacent to the bottom portion and receives heat from the heat source means that generates the high-temperature heat medium. A fuel evaporation device, wherein a bottom portion is provided with an inclined portion with the heat receiving portion side down . 2. The evaporation chamber according to claim 1, wherein any one of the evaporation chambers has a larger heat transfer area than the other evaporation chambers, and the bottom portion of the evaporation chamber includes the heat receiving portion. Fuel evaporation device. In a fuel evaporation apparatus provided with an evaporation chamber for evaporating raw fuel with a high-temperature heat medium to obtain raw fuel gas,
A plurality of raw fuel injection means for injecting the raw fuel, provided in the evaporation chamber at different distances from the outlet side of the evaporation chamber;
The target temperature of the raw fuel gas is set, and based on the set target temperature and the required injection amount of the raw fuel, the temperature of the raw fuel gas becomes a set target temperature. Raw fuel injection control means for selecting the raw fuel injection means, and injecting the raw fuel with the selected raw fuel injection means,
A fuel evaporation apparatus comprising: The evaporation chamber is connected to a plurality of evaporation chambers so that they can be ventilated in series.
The raw fuel injection means is provided in each of the plurality of evaporation chambers,
The fuel evaporation apparatus according to claim 3, wherein a plurality of raw fuel spraying means are arranged in the most upstream evaporation chamber among the plurality of evaporation chambers.

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