JPH06288692A - Heat exchanger and alcohol modified engine using the same - Google Patents

Abstract

PURPOSE:To provide a heat exchanger in which liquid is vaporized by thermal energy from a high temperature gas and an alcohol modified engine in which the exchanger is applied to a fuel modifying unit. CONSTITUTION:A heat exchanger 9A vaporizes liquid flowing to a vaporizing passage 40 with high temperature gas passed through a gas passage 45. The passage 45 is formed of a honeycomblike gas passage 47 formed by laminating corrugated sheets 45 in multiple stages. The passage 40 is formed of a ceramic fluid passage passed through the passage 45 and has a heater 44. A fluid passage is formed of a honeycomblike fluid passage 42 formed of corrugated sheets 41 and flat platelike sheets 43. The sheets 41, 43, 46 are formed of dense ceramics having excellent thermal conductivity such as SiC, AlN, Al2O3, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger for vaporizing a liquid with a high temperature gas and an alcohol reforming engine used in a fuel reformer for thermally decomposing and reforming an alcohol fuel.

[0002]

2. Description of the Related Art In recent years, environmental pollution caused by exhaust gas exhausted from an engine has become a problem, and an alcohol engine has recently attracted attention. In the alcohol engine, the content of carbon dioxide gas and carbide in the exhaust gas is very small compared to fuels such as gasoline and light oil. However, an alcohol engine that uses alcohol fuel has a problem of poor ignition performance. That is,
Alcohol has a higher latent heat for vaporization than gasoline, for example, gasoline requires 0.7% of the latent heat of vaporization of fuel, whereas alcohol requires 5% of the latent heat of vaporization of fuel, This is because alcohol fuel has the property of being difficult to vaporize. Moreover, the alcohol fuel injected from the fuel injection nozzle into the compressed air in the combustion chamber lowers the temperature of the compressed air and the wall surface of the combustion chamber due to vaporization, which worsens ignition.

Conventionally, alcohol reforming engines have been disclosed in JP-A-3-145558 and JP-A-3-145559.
There are some disclosed in Japanese Patent No. For example, JP-A-3-
The alcohol reforming engine disclosed in Japanese Patent No. 145559 crosses each of the above passages, an intake passage through which an air-fuel mixture of alcohol fuel and intake air flows, an exhaust passage through which exhaust gas from a combustion chamber flows, an air passage through which intake air flows. Honeycomb reactor disc that exchanges heat with a fluid and reforms the fuel, a fuel injection nozzle that is disposed in the intake passage upstream of the disc and that injects alcohol fuel, and the disc is rotated. It consists of a driving motor.

[0004]

By the way, it is well known in the art to improve the fuel consumption rate by reforming methanol in an alcohol engine which uses alcohol such as methanol as a fuel. The reason is that methanol decomposes thermally, and by applying heat energy to methanol, it decomposes into hydrogen gas and carbon monoxide. That is, 20 Kca per mole of methanol
When a heat quantity of 1 is given, methanol is thermally decomposed into hydrogen and carbon monoxide [CH ₃ OH + 20 Kcal → 2H ₂ + CO]. Therefore, methanol has hydrogen gas and carbon monoxide as fuel, and the methanol fuel is reformed.

Further, in a heat shield engine, when the combustion chamber has a heat shield structure, the temperature of the exhaust gas exhausted from the combustion chamber is 1500 when the engine is operating at high speed and high load.
It has risen to ℃. Therefore, it is preferable to use the exhaust gas discharged from the heat shield engine to thermally decompose and reform the alcohol fuel. However, when the engine is operating at low speed and low load, the wall surface of the combustion chamber is not in a high temperature state, the fuel takes heat of vaporization from the wall surface, and the vaporization cannot be promoted. When the fuel is alcohol, Since the latent heat for vaporization is high, the phenomenon appears significantly. Therefore, there is a problem of how to reform the alcohol fuel when the temperature of the exhaust gas is low such as when the engine is started.

Therefore, an object of the present invention is to solve the above-mentioned problems, and in order to vaporize a liquid such as alcohol fuel, a ceramic gas passage through which a gas such as exhaust gas flows and an alcohol penetrating the gas passage. It is an object of the present invention to provide a heat exchanger that is composed of a ceramic vaporization passage that introduces a liquid such as fuel and discharges it as a gas, and that favorably transfers the thermal energy of a high-temperature gas to the liquid to be vaporized.

[0007] Another object of the present invention is to solve the above-mentioned problems, and the thermal energy of exhaust gas is absorbed by alcohol fuel to thermally decompose the alcohol into hydrogen gas and carbon monoxide for reforming. Is provided with the heat exchanger, and the high temperature exhaust gas is passed through the heat exchanger to thermally decompose the alcohol fuel with the thermal energy of the exhaust gas to reduce the calorific value of the fuel. increases, an intermediate product, such as pungent smell, HC, to suppress the generation of NO _X, is that by recovering exhaust gas energy to provide alcohol reforming engines to improve fuel economy.

[0008]

In order to achieve the above object, the present invention is configured as follows. That is, the present invention is a heat exchanger having a gas passage formed in a case for passing a high temperature gas, and a vaporization passage for introducing a liquid and discharging the gas for converting the liquid into a gas through the gas passage. In the above, the gas passage is arranged with a heat shield layer interposed in the case, and the gas passage is composed of a large number of honeycomb-shaped gas passages formed by stacking corrugated sheets made of porous ceramics in multiple stages, The vaporizing passage relates to a heat exchanger characterized in that it is constituted by a ceramic fluid passage having a dense outer side and a porous inner side which penetrates the gas passage and has a heater in the passage.

Further, in this heat exchanger, the fluid passage forming the vaporization passage is composed of a large number of honeycomb-like fluid passages formed by laminating a pair of ceramic corrugated sheets to form the gas passage. The honeycomb-shaped gas passages are arranged on both sides of the vaporization passage.

In this heat exchanger, at least the honeycomb-shaped fluid passage forming the vaporization passage is
A dense flat sheet is interposed between the porous corrugated sheets, and the top surface of the corrugated sheet is joined to the flat sheet.

Further, in this heat exchanger, the honeycomb-shaped gas passages forming the gas passages are arranged in a link shape by sequentially stacking the cylindrical sheets in the radial direction, and arranging them from the periphery of the gas passages. A plurality of heat conducting cores extending to the vaporization passage in the center are arranged at intervals.

Further, in this heat exchanger, the material forming the gas passage is made of dense ceramics having a good thermal conductivity such as SiC, AlN, and Al ₂ O ₃ .

Further, in this heat exchanger, the material forming the porous corrugated passage of the vaporization passage has N inside.
It is composed of ceramics containing a metal such as i, Cu, and Pt. The ceramics are Al ₂ O ₃ and cordierite (2MgO.2Al ₂ O ₃ .5SiO ₂ ).

Alternatively, according to the present invention, a sub-chamber formed in a cylinder head having an exhaust port in which at least an exhaust valve is arranged and provided with a fuel introduction port, a main chamber formed on a cylinder side where a piston reciprocates, A communication hole that connects the sub chamber and the main chamber, a fuel supply unit that supplies alcohol fuel from a fuel tank to the sub chamber through a fuel introduction passage, a fuel introduction control valve disposed at the fuel introduction port of the sub chamber, A fuel reformer comprising a control valve arranged in the communication hole, a heat exchanger for thermally decomposing and reforming the alcohol fuel provided in the fuel introduction passage, and the fuel reformer and the exhaust port are communicated with each other. An exhaust gas passage is provided, wherein the fuel reformer connects a gas passage to the exhaust gas passage and connects the fuel introduction passage to a vaporization passage.
The present invention relates to an alcohol reforming engine, which is configured by the heat exchanger described in 2, 3, 4 or 5.

Further, in this alcohol reforming engine, the fuel introduction control valve is opened from the intake stroke to the middle of the compression stroke, and the control valve is opened near the end of the compression stroke and branched from the exhaust gas passage. And an switching valve that is switched to connect the exhaust port to the fuel reformer or the external opening passage.

[0016]

The heat exchanger and the alcohol reforming engine using the same according to the present invention are configured as described above,
It works as follows. That is, in this heat exchanger, the gas passages are arranged in the case with a heat shield layer interposed, and the gas passages are formed by stacking a plurality of ceramic corrugated sheets in a multi-tiered manner, and the top surfaces of the adjacent sheets are mutually adjacent. It is composed of a large number of small gas passages formed by joining, and the vaporization passage penetrating the gas passage is composed of a ceramic small passage and is provided with a heater, so that the vaporization passage and the gas passage are fluid leaked. It is possible to configure a stable passage without heat, to efficiently receive the heat energy of high-temperature gas in a liquid and vaporize it, and when the gas temperature is low, heat the vaporization passage with the heater to make the liquid efficient. Can be vaporized. However, in general, it is difficult to conduct heat from a gas to a liquid, but in this heat exchanger, the gas-side passage cross-sectional area can be made larger than the liquid-side passage cross-sectional area, and the heat Energy can be received by the liquid.

Alternatively, this alcohol reforming engine
A fuel reformer for arranging a control valve in a communication hole that communicates between the sub chamber and the main chamber and thermally decomposing and reforming the alcohol fuel in a fuel introduction passage for supplying alcohol fuel from a fuel tank to the sub chamber is provided. Since the fuel reformer is constituted by the heat exchanger, the fuel introduction control valve is arranged at the fuel introduction port of the sub chamber, and the exhaust port and the fuel reformer are connected by the exhaust gas passage. When the exhaust gas temperature is high, the alcohol fuel can be thermally decomposed by the thermal energy of the exhaust gas to be reformed into carbon monoxide and hydrogen to increase the calorific value of the fuel. Also, when the exhaust gas temperature is low at the time of starting,
The alcohol fuel can be vaporized or thermally decomposed by a heater provided in the heat exchanger to be reformed into carbon monoxide and hydrogen. If the fuel is vaporized, the thermal energy is small but it can operate as a gas engine.

In this alcohol reforming engine, the fuel introduction control valve is opened in the intake stroke, and the introduction of fuel into the sub chamber is completed by the middle of the compression stroke. Next, the communication hole opens near the end of the compression stroke, compressed air is introduced from the main chamber to the sub chamber, and combustion is started. With the mechanism configured at such timing, a high compression ratio can be realized, and the thermal efficiency of the engine can be improved.

Alcohol fuel is 9000 kcal.
/ Kg, but the temperature of alcohol fuel is 500 ° C-60
It receives thermal energy from the exhaust gas at 0 ° C. and thermally decomposes it into a mixed gas of CO and H ₂ , and the mixed gas is 12,000.
Thermal energy is increased to kcal / kg and reformed. Further, the mixed gas that has been modified, since the faster and lower combustion temperature combustion speed, smoke, the generation of NO _X can be suppressed. Further, by opening the communication valve by the control valve, highly compressed intake air flows into the sub chamber from the main chamber to mix the gas fuel generated by reforming the alcohol fuel with the intake air. ignited by the occurrence of the NO _X is suppressed at high burn in large fuel-rich equivalence ratio.

[0020]

Embodiments of the heat exchanger according to the present invention and an alcohol reforming engine using the same will be described below with reference to the drawings. First, an embodiment of the heat exchanger according to the present invention will be described. FIG. 1 is a perspective view showing an embodiment of a heat exchanger according to the present invention. The heat exchanger 9A has a gas passage 45 formed in a case 26 such as a cover for passing a high temperature gas G, and a vaporization passage 40 for flowing a fluid F penetrating the gas passage 45. The vaporization passage 40 can be used for introducing a liquid and releasing the gas in order to convert the liquid into a gas. The gas passage 45 is arranged in the case 26 with the heat shield layer 35 interposed therebetween, and the gas passage 45 is formed by stacking a plurality of sheets including at least a ceramic corrugated sheet 46 in multiple stages to form a large number of honeycomb-shaped gas passages 47. It consists of The vaporization passage 40 is
A ceramic fluid passage penetrating the gas passage 45 is provided with a heater 44, and the fluid passage comprises a pair of ceramic corrugated sheets 41 and a flat sheet 43 arranged between the corrugated sheets 41. It is composed of a number of honeycomb-shaped fluid passages 42 formed by stacking. The honeycomb-shaped gas passages 47 forming the gas passages 45 are arranged on both sides of the vaporization passage 40.

In this heat exchanger, the porous corrugated sheets 41 and 46 are formed by forming a ceramic sheet of SiC, AlN, Al ₂ O ₃ or the like into a corrugated shape by, for example, a gear-shaped forming machine. Can be made. The sheets forming the vaporization passage 40 and the gas passage 45 are arranged alternately in a corrugated form.
1, 46 and the flat sheet 43, 48, and the top surface of the corrugated sheet 41, 46 is the flat sheet 43,
It is joined to 48. By joining the top surfaces of the corrugated sheets 41, 46 to the dense flat sheet sheets 43, 48, the joining surfaces can be strengthened,
The honeycomb-shaped gas passage 47 and the honeycomb-shaped fluid passage 42 form small passages isolated from each other. Moreover, the vaporization passage 40 is arranged so as to intersect the gas passage 45 at a right angle. Further, the material of each sheet constituting the gas passage 45 is made of ceramics having good thermal conductivity such as SiC, AlN, Al ₂ O _{3 and the} like, and its plate thickness is 0.5.
It is formed to about 1 mm. The joint surfaces of the adjacent sheets are joined so that the gas G or the fluid F does not leak. The material forming the porous corrugated passage of the vaporization passage 40 is a ceramic containing metal such as Ni, Cu, Pt, etc., and the ceramic is A
l ₂ O ₃ , cordierite (2MgO · 2Al ₂ O ₃
・ 5SiO ₂ ).

In particular, the honeycomb-shaped fluid passage 42 constituting the vaporization passage 40 is arranged so that the porous corrugated sheet 41 is sandwiched between the dense flat sheet 43 and the top surface of the corrugated sheet 41 is a flat sheet. It is firmly joined to 43 to prevent the fluid F from leaking from the honeycomb fluid passage 42 to the honeycomb gas passage 47. However, since the periphery of the gas passage 45 is covered with the heat shield layer 35 and the case 26, it is easy to configure so that the gas G does not leak to the outside. Therefore, many honeycomb-shaped gas passages 47 are flat sheet-like sheets. It is also possible to form only the corrugated sheet 46 without using the above. Also,
Since the heater 44, that is, the heating wire is embedded in the sheet forming the vaporization passage 40, when the gas passing through the gas passage 45 is not at a high temperature, the flow of the gas G to the gas passage 45 is blocked and the heater is heated. By passing an electric current through 44, the fluid F, that is, the liquid flowing through the vaporizing passage 40 can be vaporized.

Next, another embodiment of the heat exchanger according to the present invention will be described. FIG. 2 is a perspective view showing another embodiment of the heat exchanger according to the present invention. The heat exchanger 9B of this embodiment is substantially functional as compared with the heat exchanger 9A of the above embodiment except that the shape of the heat exchanger itself, the structure of the vaporization passage, and the heat conduction core are provided. Are equivalent to each other, parts having the same functions are designated by the same reference numerals, and duplicate description will be omitted here.

In the heat exchanger 9A of this embodiment, the honeycomb-shaped gas passages 47 forming the gas passages 45 are formed in a tubular shape, and the corrugated sheets 46 are sequentially laminated in the radial direction and arranged in a link shape. ing. The vaporization passage 40 penetrates through the center of the gas passage 45. In addition, the gas passage 45
A plurality of heat-conducting cores 49 extending from the periphery to the central vaporization passage 40 and extending in the flow direction of the gas G (in FIG. 2,
(4 pieces) are arranged apart from each other. The heat conducting core 49 functions as a pillar of the corrugated sheet 46 and also serves to conduct the heat energy of the gas G around the gas passage 45 to the central vaporizing passage 40.

Next, an embodiment of an alcohol reforming engine in which the above heat exchangers 9A and 9B are constituted as a fuel reforming device will be described with reference to the drawings. 3 is a schematic explanatory view showing an embodiment of the alcohol reforming engine according to the present invention, FIG. 4 is an explanatory view showing the lower surface of the cylinder head of FIG. 3,
5 and 6 are explanatory views showing an example of valve timing in the alcohol reforming engine of FIG. This alcohol reforming engine is a sub-chamber engine that uses alcohol such as methanol as a fuel, and the alcohol fuel, that is, liquid is thermally decomposed and reformed into a mixed gas of carbon dioxide CO and hydrogen gas H _2. It improves the thermal efficiency. Further, the high temperature gas uses exhaust gas emitted from the engine.

This alcohol reforming engine includes a cylinder block 39, a cylinder head 4 fixed to the cylinder block 39, an intake port 25 formed in the cylinder head 4, and an exhaust port 2 formed in the cylinder head 4.
4, an intake valve seat 31 communicating with the intake port 25 and an exhaust valve seat 30 communicating with the exhaust port 24 are formed and arranged in the hole 29 of the cylinder head 4
0, the intake valve 27 arranged in the intake valve seat 31, the exhaust valve 6 arranged in the exhaust valve seat 30, and the auxiliary chamber wall body 23 of the heat shield structure arranged in the hole 29 formed in the cylinder head 4. The sub-chamber 2, the cylinder liner 22 fitted in the hole formed in the cylinder block 39, the cylinder liner 22
A piston 3 which reciprocates in a cylinder 21 formed in
It has a main chamber 1 of a heat shield structure formed on the cylinder 21 side, and a communication hole 5 formed in a sub chamber wall body 23 that connects the main chamber 1 and the sub chamber 2 with each other. Although the intake port 25 is formed in the cylinder head 4, the intake port may be formed in the lower portion of the cylinder instead of being formed in the cylinder head 4.

In this alcohol reforming engine, the main chamber 1 is on the cylinder 21 side where the piston 3 reciprocates, and is formed by the headliner 20 fitted in the large diameter hole 29 formed in the cylinder head 4. There is. The head liner 20 is composed of a liner upper part that constitutes a part of the cylinder 21 and a head lower surface part. A sub-chamber engine wall body 23 forming the sub-chamber 2 is integrally formed on the upper surface of the lower surface of the head. The sub-chamber wall 23 is provided with the cylinder head 4
It is fitted in the hole 29 of the.

In this alcohol reforming engine, a fuel tank 17 containing alcohol fuel, a fuel pump 16 as a fuel supply means for supplying alcohol fuel from the fuel tank 17 to the sub chamber 2 through a fuel introduction passage 19, and a fuel tank 17 are provided. Fuel storage chamber 1 that temporarily stores alcohol fuel from
5, a fuel introduction passage 19 for supplying fuel from the fuel tank 17 to the sub chamber 2, a fuel reformer 9 provided in the fuel introduction passage 19, and a fuel introduction port 2 communicating the fuel introduction passage 19 with the sub chamber 2.
8, a fuel introduction control valve 8 arranged in the fuel introduction port 28 of the sub chamber 2, a communication hole 5 for communicating the sub chamber 2 and the main chamber 1, a control valve 7 arranged in the communication hole 5, an exhaust port 24 and a fuel reformer. Exhaust gas passage 33 communicating with the quality control device 9, an external opening passage 32 connected to the exhaust gas passage 33, a switching valve 12 arranged in the exhaust gas passage 33, and a switching valve 11 arranged in the external opening passage 32.
Is to have. Of course, these switching valves 11, 12
Can also be configured by a single switching valve arranged at a branch portion between the exhaust gas passage 33 and the external open passage 32.

This alcohol reforming engine is particularly characterized by applying the heat exchanger 9A or 9B to the fuel reforming device 9. That is, the fuel reformer 9
The gas passage 4 of the heat exchanger 9A or 9B is provided in the exhaust gas passage 33.
5 and the fuel introduction passage 19 is connected to the heat exchanger 9A or 9B.
Of the heat exchanger 9A by connecting to the vaporization passage 40 of
Or 9B can be applied. A heater 44 is embedded in the fuel introduction passage 19, and the heater 44 is configured to be heated by a command from the controller 10.

Further, the fuel storage chamber 15 temporarily stores the alcohol fuel from the fuel tank 17 by the operation of the fuel pump 16. Since the fuel fuel is stored in the fuel storage chamber 15, the alcohol fuel is used as a heating device. Ceramic glow plug 18 with excellent corrosion resistance to
Are arranged. The fuel reformer 9 is the heat exchanger 9A or 9B described above, and is provided in the fuel introduction passage 19 downstream of the fuel storage chamber 15. The fuel reforming device 9 receives the heat energy of the high-temperature exhaust gas to thermally decompose the alcohol fuel and reform it into a mixed gas consisting of carbon dioxide CO and hydrogen gas H ₂ . The pressure of the fuel sent from the fuel tank 17 to the fuel storage chamber 15 by the fuel pump 16 is
The pressure is low at about 1 kg / cm ² . Therefore, the fuel storage chamber 1
5 is provided with a glow plug 18, and the alcohol fuel is heated by electric energy, and the alcohol fuel is vaporized into vapor and sent to the fuel reformer 9, and the fuel reformer 9 promotes vaporization of the fuel.

In the fuel reformer 9, for example, a vaporization passage 40 made of ceramics having a high corrosion resistance to alcohol fuel penetrates through the center of a casing or case 26, and a honeycomb is provided outside the vaporization passage 40. Gas passage 4
5 are arranged. A heater 44 is embedded in the vaporization passage 40 so as to promote the vaporization of fuel.

Further, as shown in FIG. 5, the fuel introduction control valve 8 is opened from the intake stroke to the middle of the compression stroke to open the fuel introduction port 28 of the sub-chamber 2, and the fuel introduction passage 19 and the sub-chamber 2 are opened. And the reformed fuel reformed by the fuel reservoir 15 or the fuel reformer 9 are supplied to the sub chamber 2. Furthermore, the control valve 7
As shown in FIG. 3, the communication hole 5 opened near the end of the compression stroke is opened to connect the main chamber 1 and the sub chamber 2 with each other, and the compressed air compressed in the main chamber 1 is Is supplied to the sub chamber 2. In some cases, the fuel introduction control valve 8 is driven by electromagnetic force, and the fuel introduction control valve 8 can be set so as to determine the valve opening period in response to the operating state of the engine load. It is also possible to supply a large amount of reformed fuel to the sub chamber 2.

In this alcohol reforming engine, the switching valves 11 and 12 are opened / closed or switched by operating the valve actuators 13 and 14 in response to a command from the controller 10. When the exhaust gas temperature is below a predetermined value, the controller 10 energizes or operates the glow plug 18 arranged in the fuel storage chamber 15 provided in the fuel introduction passage 19 to heat the alcohol fuel to be thermally decomposed and thermally reformed. At the same time, the switching valve 11 is opened and the switching valve 12 is closed so that exhaust gas is discharged to the outside through the external opening passage 32. In addition, the controller 10
Is the glow plug 1 when the exhaust gas temperature is above a specified value.
8 is turned off, that is, deactivated, the switching valve 11 is closed and the switching valve 12 is opened, and exhaust gas is supplied to the fuel reformer 9 to heat the alcohol fuel to heat it. Control to decompose and heat reform.

Further, in this alcohol reforming engine, the combustion chambers of the main chamber 1 and the sub chamber 2 and the piston head portion of the piston 3 are constructed to have a heat shield structure with low thermal conductivity ceramics and heat resistant ceramics. Therefore, it is preferable to maintain the exhaust gas temperature at a high temperature, increase the exhaust gas energy, and efficiently perform the thermal decomposition of the alcohol fuel. For example, as the heat shield structure for the main chamber 1, the sub chamber 2 and the piston head portion, ceramics such as silicon nitride and silicon carbide having high temperature strength and excellent heat resistance are used as the wall body of the surface exposed to the combustion gas. By disposing a heat shield material such as aluminum titanate or potassium titanate inside the wall body, a high degree of heat shield can be secured.

This alcohol reforming engine is constructed as described above and is operated as follows. This alcohol reforming engine, as shown in FIG.
It is operated by sequentially repeating four strokes of a compression stroke, an expansion stroke and an exhaust stroke. First, at the start of the engine and during a predetermined period after the start, the valve actuator 13 is operated by a command of the controller 10 to switch the valve. 11
Is opened and the valve actuator 14 is operated to close the switching valve 12, and further, the glow plug 18 and the heater 44 are opened.
To heat or thermally decompose the alcohol fuel to produce a mixed gas of CO and H _2, that is, a reformed fuel. Then, in the intake stroke, the intake valve 27 opens the intake port 25 to supply intake air to the main chamber 1, and the control valve 7 arranged in the communication hole 5 closes the communication hole 5 to close the fuel introduction control valve 8 And the reformed fuel is supplied from the fuel storage chamber 15 to the sub chamber 2 through the fuel introduction passage 19. At this time, since the exhaust gas after combustion remains in the sub chamber 2, when the reformed fuel from the fuel storage chamber 15 is introduced, the reformed fuel receives heat and is activated in the sub chamber 2. To do.

Next, in this alcohol reforming engine, in the compression stroke, the communication hole 5 is closed by the control valve 7, and the intake air is highly compressed in the main chamber 1 to increase the compression ratio. Next, the control valve 7 is connected to the communication hole 5 near the end of the compression stroke.
Is opened, and compressed air of high compression and high temperature is allowed to flow from the main chamber 1 to the sub chamber 2 through the communication hole 5, the intake air promotes mixing with the activated reformed fuel, and is ignited and burned. It rapidly progresses and burns in a fuel-rich state with NO _X reduced, then the flame of the sub-chamber 2 is ejected into the main chamber 1 and shifts to the expansion stroke to mix with the fresh air existing in the main chamber 1. Promote to complete secondary combustion in a short period of time. In this expansion stroke, the communication hole 5
While maintaining the open state, the flame is jetted from the sub chamber 2 to the main chamber 1 to perform work, and the communication hole 5 is closed by operating the control valve 7 near the end of the exhaust stroke.

Next, this alcohol reforming engine
When the combustion is vigorously performed and the temperature of the exhaust gas becomes high, the valve actuator 13 is operated to close the switching valve 11 and the valve actuator 14 is operated to open the switching valve 12 according to a command from the controller 10, and the glow plug is further activated. The power supply to 18 and the heater 44 is stopped. The exhaust gas is sent from the exhaust port 24 to the fuel reformer 9 through the exhaust gas passage 33. Since the exhaust gas has a high temperature, the exhaust gas energy is applied to the alcohol fuel to heat and thermally decompose the alcohol fuel to produce a mixed gas of CO and H _2, that is, a reformed fuel. The reformed fuel is supplied to the sub chamber 2 by the opening of the fuel introduction control valve 8 and burns in the same manner as described above. In the intake stroke, intake port 2
The intake air sucked into the main chamber 1 from the control valve 7 is connected to the communication hole 5
Is closed and the intake air is not supplied to the sub chamber 2, the piston 3 is compressed in the upward compression stroke, so that even if the intake air is highly compressed in the main chamber 1, it is supplied to the sub chamber 2. Since the reformed fuel is shut off from the main chamber 1 by the control valve 7, self-ignition does not occur and knocking does not occur.

Further, since the control valve 7 opens the communication hole 5, intake air having a high compression ratio flows from the main chamber 1 into the sub chamber 2, the reformed fuel and intake air are mixed and ignited, High-speed combustion is performed in a fuel-rich state where the equivalence ratio is large, and the generation of NO _X is suppressed. Furthermore, in the sub-chamber 2 containing the exhaust gas after combustion,
The reformed fuel is introduced from the fuel storage chamber 15 through the fuel reformer 9, and the reformed fuel receives heat in the sub chamber 2 and is activated.

[0039]

The heat exchanger and the alcohol reforming engine using the same according to the present invention are configured as described above and have the following effects. That is, in this heat exchanger, the gas passage is arranged in the case with a heat shield layer interposed therebetween.
The gas passage is composed of a large number of small gas passages formed by laminating a plurality of ceramic corrugated sheets in multiple stages and joining the top surfaces of the adjacent sheets to each other, and the vaporization passage passing through the gas passages is Since it is composed of a ceramic small passage and is provided with a heater, the vaporization passage and the gas passage can be formed as stable passages without fluid leakage, and the heat energy of the high temperature gas is efficiently received by the liquid to be vaporized. Further, when the gas temperature is low, the heater can heat the vaporization passage to efficiently vaporize the liquid.

Moreover, since this heat exchanger can efficiently conduct the heat energy of the high temperature gas to the liquid and vaporize it, it is effectively applied as a heat exchanger of the fuel reformer of the alcohol reforming engine. be able to. That is, in the alcohol reforming engine to which the heat exchanger is applied as a fuel reforming device, a control valve that is opened near the end of the compression stroke is arranged in a communication hole that communicates between the sub chamber and the main chamber. The alcohol fuel of the above is supplied to the sub chamber through the fuel introduction passage, the alcohol fuel provided in the fuel introduction passage is thermally decomposed and reformed by the fuel reforming device, and the fuel introduction control valve disposed at the fuel introduction port of the sub chamber is provided. Is opened from the intake stroke to the middle of the compression stroke to supply the reformed fuel to the sub chamber, and the exhaust port and the fuel reformer are communicated with each other through the exhaust gas passage,
Since the exhaust port is communicated with the fuel reformer or the external open passage by the switching valve, alcohol fuel can be thermally decomposed by the exhaust gas energy to be reformed into CO and H ₂ by the fuel reformer, and ignition can be performed. Since the exhaust gas energy can be effectively used as well as the heat energy can be improved, the exhaust gas energy can be effectively recovered.

In addition, this alcohol reforming engine is controlled by the controller when the exhaust gas temperature is below a predetermined value.
The heating device disposed in the fuel reservoir provided in the fuel introduction passage is operated to heat and reform the alcohol fuel, and the switching valve is switched to the side where exhaust gas is exhausted through the external opening passage, and the exhaust gas temperature is also changed. Is above a certain value,
Control for switching the switching valve so as to connect the exhaust port to the fuel reformer for heating and reforming the alcohol fuel by supplying exhaust gas to the fuel reformer while heating the heating device in a non-operating state. Therefore, the alcohol fuel can be effectively reformed.

Further, since the intake air is introduced into the main chamber in a state in which the control of the communication hole is closed and the main chamber and the sub chamber are shut off, a high compression ratio for highly compressing the intake air can be realized. Further, when the control valve is actuated and the communication hole is opened, the air highly compressed and heated to a high temperature from the main chamber flows into the sub chamber at once, and the mixture of the reformed fuel and the intake air at once. promoting ignites, since the in auxiliary chamber is fast combusted in large fuel-rich equivalence ratio, occurrence of the NO _X is suppressed. Then, the pressure in the sub chamber rapidly rises due to the combustion, and the combustion is promoted, and at the same time, the flame blows from the sub chamber to the main chamber all at once through the communication hole, and the flame is fresh in the main chamber. And premixed combustion are promoted to increase the combustion speed and complete the ideal secondary combustion. Accordingly, the alcohol reforming engine, NO _X, can significantly reduce the generation of HC and the like, can provide a high efficiency of the engine.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a heat exchanger according to the present invention.

FIG. 2 is a perspective view showing another embodiment of the heat exchanger according to the present invention.

FIG. 3 is an explanatory view showing an embodiment of an alcohol reforming engine using the heat exchanger according to the present invention.

FIG. 4 is an explanatory view showing a lower surface of a cylinder head of the alcohol reforming engine of FIG.

5 is an explanatory diagram showing an example of valve timing in the alcohol reforming engine of FIG. 3. FIG.

[Explanation of symbols]

 1 Main chamber 2 Sub chamber 3 Piston 4 Cylinder head 5 Communication hole 6 Exhaust valve 7 Control valve 8 Fuel introduction control valve 9 Fuel reformer 10 Controller 11, 12 Switching valve 15 Fuel reservoir chamber 16 Fuel pump 17 Fuel tank 18 Glow plug (Heating device) 19 Fuel introduction passage 21 Cylinder 24 Exhaust port 26 Case 28 Fuel introduction port 33 Exhaust gas passage 40 Evaporation passage 41,46 Corrugated sheet 42 Honeycomb fluid passage 43,48 Flat sheet 45 Gas passage 47 Honeycomb Gas passage 49 Heat conduction core

Claims (8)

[Claims] 1. A heat exchanger having a gas passage formed in a case for passing a high-temperature gas, and a vaporization passage for penetrating the gas passage and introducing the liquid to convert the liquid into a gas and discharging the gas. The gas passages are arranged in the case with a heat shield layer interposed therebetween, and the gas passages are composed of a large number of honeycomb-shaped gas passages formed by stacking corrugated sheets made of porous ceramics in multiple stages. The heat exchanger is characterized by comprising a ceramic fluid passage having a dense outer side and a porous inner side which penetrates the gas passage and has a heater in the passage. 2. The honeycomb-shaped gas passage that constitutes the gas passage is constituted by a number of honeycomb-shaped fluid passages that are formed by stacking a pair of ceramic corrugated sheets. The heat exchanger according to claim 1, wherein the heat exchangers are arranged on both sides of the vaporization passage. 3. The honeycomb fluid passage forming at least the vaporization passage has a dense flat sheet interposed between the porous corrugated sheets, and the top surface of the corrugated sheet is the flat sheet. The heat exchanger according to claim 2, wherein the heat exchanger is joined. 4. The gas passages forming the gas passages are arranged in a link shape by sequentially stacking the cylindrical sheets in the radial direction, and the vaporization passages in the center from the periphery of the gas passages. The heat exchanger according to claim 1, wherein a plurality of heat conducting cores extending up to are arranged at intervals. 5. The material forming the gas passage is SiC,
The heat exchanger according to claim 1, wherein the heat exchanger is made of ceramics having good thermal conductivity such as AlN and Al ₂ O ₃ . 6. The heat exchange according to claim 1, wherein the material forming the porous corrugated passage of the vaporization passage is a ceramic containing metal such as Ni, Cu, Pt, etc. inside. vessel. 7. A sub-chamber formed in a cylinder head having an exhaust port in which at least an exhaust valve is arranged and provided with a fuel introduction port, a main chamber formed on a cylinder side where a piston reciprocates, the sub-chamber and the sub-chamber. A communication hole communicating with the main chamber, a fuel supply means for supplying alcohol fuel from a fuel tank to the sub chamber through a fuel introduction passage, a fuel introduction control valve arranged at the fuel introduction port of the sub chamber, and the communication hole. A control valve arranged, a fuel reformer comprising a heat exchanger for thermally decomposing and reforming alcohol fuel provided in the fuel introduction passage, and an exhaust gas passage communicating the fuel reformer with the exhaust port. 7. The fuel reformer according to claim 1, wherein the fuel reformer has a gas passage connected to the exhaust gas passage and the fuel introduction passage connected to a vaporization passage. Heat exchange An alcohol reforming engine, which is configured by a converter. 8. The fuel introduction control valve is opened from the intake stroke to the middle of the compression stroke, the control valve is opened near the end of the compression stroke, and has an external open passage branched from the exhaust gas passage. The alcohol reforming engine according to claim 7, further comprising a switching valve that is switched to connect the exhaust port to the fuel reformer or the external open passage.