JP2001152846A - Engine equipped with fuel-reforming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reform gas fuel by utilizing heat energy of exhaust gas, recover energy by driving a turbine with high temperature steam, generated with a heat exchanger, supply part of exhaust gas to a combustion chamber as EGR gas, in an engine equipped with a fuel-reforming device. SOLUTION: This engine 1 has a fuel reforming device 35 for reforming gas fuel, a heat exchanger 4 for generating high-temperature steam, a CO2 separating device 36 for separating CO2 from the exhaust gas, and an EGR control valve 7 for taking in part of the exhaust gas as EGR gas. The fuel reforming device 35 reforms CH4 in the gas fuel into CO and H2 under the presence of hot water heated with the heat exchanger 5, and enhances heat efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention is a fuel reformer for converting fuel gas to the CH ₄ as a main component by utilizing the exhaust gas heat energy to the reforming fuel of CO and H ₂ by thermal decomposition For the equipped engine.

[0002]

2. Description of the Related Art Natural gas is known to have extremely large reserves on the earth, and the most promising fuel for the 21st century is said to be natural gas. In recent years, engines using natural gas as fuel have been developed. However, research has just begun on how to achieve the performance of the engine, and at present, sufficient results have not been achieved.

[0003] In an internal combustion engine, what governs thermal efficiency is a large compression ratio, a combustion rate, and an equivalence ratio, and it is well known that thermal efficiency depends on these three conditions. Even if the above three conditions are satisfied, the theoretical thermal efficiency is at most about 60%. Therefore, in an internal combustion engine using natural gas as a fuel, it is necessary to reuse and recover the heat energy of the exhaust gas in order to ensure a higher thermal efficiency.

Conventionally, a heat shield type engine equipped with a turbocharger has a turbocharger equipped with a turbine and a compressor installed in the first stage of an exhaust system, and energy recovery comprising a turbine having a generator downstream of the turbocharger. Equipment is installed. In the heat shield type engine, the combustion chamber has a heat shield structure, and the thermal energy of the exhaust gas discharged from the combustion chamber is recovered as electric power by a turbocharger or an energy recovery device, or overheated by driving a compressor of the turbocharger. Collected by feeding. An energy recovery system that does not reduce the efficiency of exhaust gas energy recovery with respect to the above-mentioned heat shield type engine is disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 5-17972.

[0005] The cogeneration system is
The motive power is extracted as electric energy by a generator, and the heat energy of the exhaust gas is heated by a heat exchanger provided in an electric power or exhaust passage to make hot water and used for hot water supply.
An example of the cogeneration system is disclosed in Japanese Patent Application Laid-Open No. 6-33707. The cogeneration system is rated for operation and has small load fluctuations, and is expected to be used as a power supply system in urban areas and mountainous areas. It generates steam using exhaust gas energy and recovers the steam energy as electric energy. The turbocharger is driven by exhaust gas energy, and an energy recovery device including a generator provided in the turbocharger is provided.

[0006]

By the way, in order to utilize the heat energy of the exhaust gas, (1) the combustion chamber of the internal combustion engine must be constructed in a heat shielding structure so that the heat energy of the exhaust gas is not radiated to the outside. (2) increasing the thermal efficiency by converting the thermal energy of the exhaust gas into motive power by a mechanical method using a turbocharger or the like, and (3) chemically converting the remaining thermal energy of the thermal energy recovered by the mechanical method (4) Further, the remaining heat energy may be converted into steam energy by evaporating water with a heat exchanger.

[0007] A diesel engine operating in a diesel cycle can be configured to have higher thermal efficiency than a gasoline engine. In a gasoline engine, the compression ratio is about 8 to 10, and the equivalent ratio (theoretical air amount corresponding to fuel / the actual air amount) is about 0.8 to 1.1. The actual thermal efficiency is about 35% even if frictional heat loss is subtracted. On the other hand, in the case of a diesel engine, the compression ratio is about 16 to 20, and the equivalent ratio of theoretical value required for fuel / cylinder intake air is about 0.6 to 0.8. %, And the actual heat efficiency is about 45% even if frictional heat loss is subtracted. Generally, the diesel engine used has a thermal efficiency of about 42% for a normal engine, an exhaust loss of about 30%, a cooling loss of about 20%, and a mechanical loss of about 8%.

Therefore, in the diesel engine, the combustion chamber and the exhaust pipe are formed in a heat shielding structure in order to provide the exhaust gas with heat energy of cooling loss, thereby preventing heat from being radiated to the outside and reducing the temperature of the exhaust gas. By increasing the temperature, the thermal energy of the exhaust gas can be recovered by driving a turbine or the like, and the thermal efficiency can be improved. Generally, the temperature of exhaust gas discharged from an adiabatic engine is about 800 to 900 ° C and is recovered by driving an exhaust turbine. However, the exhaust gas after passing through the exhaust turbine drops to about 650 to 700 ° C. However, if the exhaust gas is discharged to the outside as it is, large heat energy will be wasted.

Therefore, a Rankine cycle is known as a method for recovering thermal energy from exhaust gas passing through a turbocharger (for example, Japanese Patent Application Laid-Open No. 11-6601). The Rankine cycle uses water as a medium, converts the water into steam with the thermal energy of exhaust gas, converts the steam energy into power, and condenses the steam again. You need a water bowl,
There is a problem that the device itself becomes complicated.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem, and a turbocharger is driven by exhaust gas discharged from a combustion chamber, and the exhaust gas discharged from the turbocharger has Gas fuel is thermally decomposed using heat energy to convert it to reformed fuel, and then the heat energy of the exhaust gas discharged from the fuel reformer is recovered by a heat exchanger and then discharged from the heat exchanger. Part of the exhaust gas is recycled to the combustion chamber through a water separator,
The heat energy of the exhaust gas recirculated to the combustion chamber and the exhaust gas exhausted from the turbocharger converts water into steam, and the generated steam is sent to the turbocharger turbine to increase the torque of the turbine. An engine equipped with a fuel reformer that separates CO ₂ from exhaust gas and uses the hot water generated in the heat exchanger to thermally decompose the gaseous fuel, CH ₄ , to improve the thermal efficiency as a reformed fuel To provide.

According to the present invention, there is provided a turbocharger provided in an exhaust pipe through which exhaust gas discharged from a combustion chamber flows, and provided in a downstream side of a turbine of the turbocharger. A fuel reformer for decomposing and reforming, a CO ₂ separator for separating CO ₂ from the exhaust gas passing through a first heat exchanger provided downstream of the fuel reformer, and the first heat A second heat exchanger for heating the hot water supplied to the exchanger by using thermal energy of EGR gas and intake air sent from a compressor of the turbocharger, and reformed fuel sent from the fuel reformer wherein comprises a fuel supply device for supplying to the combustion chamber, supplying said water heated by the CO ₂ separation and the second heat exchanger the separated CO ₂ and in the apparatus to the fuel reforming apparatus, gas Fee CH ₄ to an engine provided with a fuel reforming apparatus comprising a thermally decomposed into CO ₂ and under CO and H ₂ in the presence of the water.

In the fuel reformer, CH ₄ is thermally decomposed into CO and H ₂ in the presence of CO ₂ and H ₂ O.
A metal catalyst such as Ru, Pt, and Ni is contained.

This engine is provided with an EGR device for sending a part of the exhaust gas passing through the CO ₂ separation device to the combustion chamber by a compressor of the turbocharger.

This engine sends steam generated by the first heat exchanger to the turbine to increase the driving force of the turbine.

This engine is provided with a water separator for eliminating water droplets generated by colliding the exhaust gas passing through the CO ₂ separator with the intake air from the air cleaner.
The dry EGR gas and the intake air that have passed through the water separator are supplied to the combustion chamber by the compressor of the turbocharger.

The engine supplies the water to the second heat exchanger and supplies the hot water heated by the second heat exchanger to the first heat exchanger and the fuel reformer. It has.

In this engine, another water separator for separating moisture from intake air supplied from the second heat exchanger to the combustion chamber is provided in an intake pipe downstream of the second heat exchanger. .

This engine has a third heat exchanger in a water passage from the second heat exchanger to the fuel reformer, and the reformer from the fuel reformer is operated by the third heat exchanger. Fuel is cooled to an appropriate temperature and supplied to the combustion chamber, and the water from the second heat exchanger is heated by the third heat exchanger and sent to the fuel reformer.

[0019] The turbocharger has a generator / motor provided on a shaft connecting the turbine and the compressor.

Alternatively, the present invention provides a fuel reforming apparatus for thermally decomposing and reforming gaseous fuel using exhaust gas heat energy provided in an exhaust pipe through which exhaust gas discharged from a combustion chamber having a heat insulating structure flows. , CO ₂ separating the fuel reforming turbocharger with a generator provided on the downstream of the apparatus, CO ₂ from the exhaust gas passing through the first heat exchanger provided on the downstream of the turbocharger A separator, and a second heat exchanger that heats the hot water supplied to the first heat exchanger by using heat energy generated by compression of EGR gas and intake air sent from the compressor of the turbocharger; and A fuel supply device for supplying reformed fuel sent from a fuel reformer to the combustion chamber;
₍₂ ) CO ₂ separated by the separation device and water heated by the second heat exchanger are supplied to the fuel reformer, and CH ₄ of the gaseous fuel is converted under the presence of CO ₂ and H ₂ O. The present invention relates to an engine provided with a fuel reforming apparatus which is configured to thermally decompose CO and H ₂ in CO.

The engine equipped with the fuel reformer, which is configured as described above, in the fuel reforming apparatus, also CH ₄ of natural gas mainly composed of the presence of the CO ₂ and H ₂ O And thermally decompose to CO and H ₂ efficiently. That is, CH ₄ +
CO ₂ → 2CO + 2H ₂ and CH ₄ + H ₂ O → CO + 3
H ₂ . These reformed fuels are sucked by a pump, compressed and sent to the combustion chamber. The thermal efficiency of the reformed fuel, CO, H _2, and the natural gas, CH ₄ , is as follows. CH ₄ + 2O ₂ → CO ₂ + 2H ₂ O + 191,290 k
cal / kmol 2CO + 2H ₂ + 2O ₂ → 2CO ₂ + 2H ₂ O + 25
0,580 kcal / kmol CO + 3H ₂ + 2O ₂ → CO ₂ + 3H ₂ O + 240,4
70 kcal / kmol Here, rather than mixing and reforming CH ₄ with H ₂ O,
Although reforming by mixing CO ₂ with H ₄ is advantageous in terms of thermal efficiency, C separated from exhaust gas discharged from the combustion chamber
Considering the flow rate of O ₂ , in the reforming of CH ₄ , CO ₂ :
H ₂ O = 2: 1 is practical.

This engine converts water into steam by the thermal energy of the exhaust gas recirculated to the combustion chamber and the exhaust gas exhausted from the turbocharger, and sends the generated steam to the turbine of the turbocharger. Since the rotational force of the exhaust gas is increased, the heat energy of the exhaust gas is converted into steam energy and recovered as power, and the amount of energy recovery can be increased.
Thermal efficiency can be improved.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an engine having a fuel reformer according to the present invention will be described with reference to the drawings. First, an embodiment of an engine provided with a fuel reformer according to the present invention will be described with reference to FIG.

As shown in FIG. 1, the engine 1 uses a gas such as natural gas as a fuel and can be applied to, for example, a cogeneration system or an automobile engine. The engine 1 has, for example, a suction stroke, a compression stroke,
It is operated in a diesel cycle by sequentially repeating four strokes of an expansion stroke and an exhaust stroke.
It is preferable to apply the present invention to an engine having a small load fluctuation in a stationary cogeneration system. The engine 1 is configured as a multi-cylinder engine, and has an exhaust manifold 31 for discharging exhaust gas from each combustion chamber 2.
And an intake manifold 27 for supplying intake air to the combustion chamber 2 through the intake pipe 25. The intake air from the intake pipe 25 and the EGR gas are supplied to the combustion chamber 2 of each cylinder through the intake manifold 27, and the exhaust gas from each combustion chamber 2 is collected by the exhaust manifold 31 and discharged to the exhaust pipe 12. The combustion chamber 2 and the exhaust pipe 12 are formed in a heat shielding structure by a ceramic member, a heat shielding layer, and the like.

The engine 1 drives the turbine 20 of the turbocharger 3 with the exhaust gas discharged from the combustion chamber 2 to mechanically recover the exhaust gas energy. under CO and H ₂ in the presence of a CH ₄ CO ₂ and H ₂ O by utilizing thermal energy
It is characterized in that it is thermally decomposed into reformed fuel and chemically recovered, and further, the heat energy of the exhaust gas is recovered by the heat exchanger 4. The engine 1 supplies steam generated by a kind of Rankine cycle (not provided with a condenser) provided in an exhaust system through which exhaust gas discharged from the combustion chamber 2 flows to the turbine 20 of the turbocharger 3. To increase the driving force of the turbine 20 and
2 and an energy recovery device for recovering exhaust gas energy for driving the compressor 21 (mechanical recovery of exhaust gas energy). In particular, the engine 1 is heated by CO ₂ separated from the exhaust gas and the thermal energy of the exhaust gas and uses hot water (H ₂ O) to generate CH 2 of a gas fuel such as natural gas by the thermal energy of the exhaust gas. It is characterized by improving thermal efficiency by thermally decomposing ₄ (chemical recovery of exhaust gas energy). The gas fuel is supplied from the fuel tank 40 having the fuel pump 47 to the fuel reformer 35 through the mixing chamber 39. Further, the engine 1 uses a part of the exhaust gas as E
An EGR device that recirculates the GR gas to the combustion chamber 2 is provided.

The engine 1 equipped with this fuel reformer is
Exhaust mainly for flowing exhaust gas discharged from the combustion chamber 2
Turbocharger 3, turbocharger provided in pipe 12
The exhaust gas heat provided downstream of the turbine 20 of the jaw 3
Fuel that reforms gas fuel by thermal decomposition using energy
The heat provided downstream of the reformer 35 and the fuel reformer 35
Exchanger 4 (first heat exchanger), exhaust gas passing through heat exchanger 4
From gas to CO_TwoTo separate CO_TwoSeparator 36 and heat
Heat exchanger 5 for generating hot water to be supplied to the heat exchanger 4 (second heat exchanger 5).
Heat exchanger), and the reformer delivered from the fuel reformer 35.
Supply device (fuel pump) for supplying high quality fuel to the combustion chamber 2
38 and a fuel injection nozzle 46). engine
1 is the CO 2 in the above configuration._TwoSeparated by the separation device 36
CO _TwoAnd hot water heated by heat exchanger 5 for fuel reforming
Supplied to the device 35 and the gas fuel CH_FourTo CO_TwoAnd H_TwoO
CO and H in the presence of_TwoIs thermally decomposed into

The gas fuel mainly composed of CH ₄ in the fuel tank 40 is fed into the mixing chamber 39 through the fuel supply pipe 42 by the fuel pump 48 provided in the fuel tank 40.
The CO ₂ and H ₂ O are mixed in the mixing chamber 39 and the fuel reformer 3
It is sent to 5. The fuel reformer 35 is formed of a catalytic heat exchanger, in which CH ₄ is reformed into CO and H _2, and the reformed gaseous fuel passes through the fuel supply pipe 44 by the operation of the fuel pump 38. It is sucked into the exchanger 37 (third heat exchanger), cooled by the heat exchanger 37 and supplied to each combustion chamber 2 through the fuel supply pipe 45. Further, the turbocharger 3 includes a turbine 20 driven by exhaust gas,
Compressor 21 attached to shaft 23 connecting turbine 20 and turbine 20 and compressor 21
And a generator / motor 22 provided on the shaft 23. The generator / motor 22 is a turbine 20
And the exhaust gas energy can be recovered as electric energy.

The water pump 9 has a function of supplying water to the heat exchanger 5 and a function of supplying hot water heated by the heat exchanger 5 to the heat exchanger 4 and the fuel reformer 35. The water supplied to the heat exchanger 5 is supplied from a water source such as a water tank or a tap to a water pump 9.
Is supplied to the heat exchanger 5 through the water passage 26.
In the heat exchanger 5, the water fed by the water pump 9 is supplied to the EG sent from the compressor 21 of the turbocharger 3.
Heating is performed using the thermal energy of the R gas and the intake air.
Hot water generated by the heat exchanger 5, that is, hot water, is partially
Then, the fuel is sent to the heat exchanger 37 through the heat exchanger 3, and the reformed fuel from the fuel reformer 35 is cooled to an appropriate temperature by the heat exchanger 37. The reformed fuel adjusted to an appropriate temperature by the heat exchanger 37 is sent from the fuel injection nozzle 46 to the combustion chamber 2 by the fuel pump 38. The remaining hot water generated by the heat exchanger 5, ie, hot water, is sprayed by the water injection nozzle 50 through the water passage 24 and sent to the heat exchanger 4. The steam generated by the heat exchanger 4 is The gas is sent to the turbine 20 of the turbocharger 3 through the passage 19 and
Performs the function of increasing the driving force of the motor.

The CO ₂ separation device 36 is constituted by, for example, a separation membrane or the like, and the exhaust gas whose temperature has decreased (for example, 150 ° C.) is sent through the heat exchanger 4. If the temperature of the exhaust gas is about 150 ° C., the separation membrane can separate CO ₂ contained in the exhaust gas, and the separated CO ₂ is supplied to the gas fuel and the hot water through a CO ₂ supply pipe 41. Is supplied to the mixing chamber 39 to which is supplied. The exhaust pipe 14 downstream of the CO ₂ separation device 36 is provided with an EGR control valve 7 for supplying a part of the exhaust gas to the combustion chamber 2 as EGR gas. The EGR control valve 7 sends a part of the exhaust gas as the EGR gas to the water separator 8 through the EGR gas passage 16 and discharges the rest of the exhaust gas to the outside through the exhaust pipe 15.

The fuel reforming unit 35 is configured as a catalytic heat exchanger.
And CH_FourTo CO_TwoAnd H_TwoIn the presence of O and CO
H_TwoMetal catalyst such as Ru, Pt, Ni etc.
Is housed. In the fuel reformer 35, natural gas
Main component CH_FourIs CO_TwoAnd H _TwoCO in the presence of O
And H_TwoThermal decomposition efficiently. That is, CH_Four+ CO_Two→
2CO + 2H_TwoAnd CH_Four+ H_TwoO → CO + 3H_Twothis
These reformed fuels are sucked by the fuel pump 38, compressed and burned.
Send to room 2. Natural gas CH_FourTo CO_TwoAnd H_TwoO
CO and H using heat energy of exhaust gas_TwoWhen
When pyrolyzed to reformed fuel_FourTo H_TwoMix O
CH rather than reforming_FourTo CO_TwoMixing and reforming
Is more advantageous in terms of thermal efficiency, but is discharged from the combustion chamber 2.
CO separated from exhaust gas_TwoInsufficient absolute flow rate
Therefore, water from the water source is supplied to the heat exchanger 5 by the water pump 9.
Heating through a heat exchanger 37 to produce hot water as mixing water 39.
And send to H_TwoUse O. Therefore, CH_FourHeat
In solution reforming, CO_TwoAnd H_TwoThe ratio with O is about 2 to 1.
The degree is realistic.

The EGR device provided in the engine 1 is a CO ₂ device.
A part of the exhaust gas passing through the separator 36 is sent as EGR gas into the combustion chamber 2 by the compressor 21 of the turbocharger 3, and is sucked from the exhaust gas passing through the CO ₂ separator 36 and the air cleaner 28 through the intake pipe 17. A water separation device 8 is provided to eliminate water droplets generated by colliding with air. The dry EGR gas and the intake air that have passed through the water separator 8 are supplied to the heat exchanger 5 by the compressor 21 of the turbocharger 3, cooled by the heat exchanger 5, and supplied to the combustion chamber 2.

In the engine 1, since a part of the exhaust gas from the EGR control valve 7 is sent as EGR gas to the compressor 21 of the turbocharger 3, the EGR gas passage 16 extending from the EGR control valve 7 supplies intake air to the compressor 21. And the EGR gas passage 1
A water separation device 8 is provided at the junction of the intake pipe 6 and the intake pipe 17. The intake air is supplied to the water separation device 8 through the air cleaner 28, mixed with the EGR gas in the water separation device 8, and supplied to the combustion chamber 2 using the gas from which moisture has been removed as intake air. It will be drained. Furthermore, the EGR sent out from the compressor 21
The intake air of the gas and the intake air is cooled by the heat exchanger 5, thereby lowering the saturated steam pressure and generating a small amount of water. The water is separated by the water separator 11, cooled, and cooled. The separated dry intake air is supplied from the intake manifold 27 to each of the combustion chambers 2, and the water is drained from the drain pipe 34 to the outside. In some cases, the water discharged from the drain pipes 33 and 34 is supplied to the water separation devices 8 and 11.
Can be used to cool the water separators 8 and 11 by spraying water to the outside.

The EGR device provided in the engine 1 is provided with an EGR device provided in an exhaust pipe 14 downstream of the heat exchanger 4.
The exhaust gas flow rate is controlled by the control valve 7 in accordance with the operating state of the engine 1. Engine 1
Are provided with a load sensor 29 for detecting an engine load, a rotation sensor 30 for detecting an engine speed, and a temperature sensor 32 for detecting an exhaust gas temperature. The controller 10 controls the flow rate of water supplied to the heat exchangers 4 and 5 by controlling the water pump 9 while controlling the flow rate of exhaust gas in accordance with detection signals from the load sensor 29, the rotation sensor 30 and the temperature sensor 32. And an optimal energy recovery system can be configured. EGR control valve 7 to E
The exhaust gas sent into the GR gas passage 16 is separated from the water by the water separator 8 and the air cleaner 2.
The air is mixed with the intake air taken in from 8 to generate intake air.

Hot water sprayed from the heat exchanger 5 through the water passage 24 by the water injection nozzle 50 and sent to the heat exchanger 4 is heated by the heat energy of the exhaust gas in the heat exchanger 4 to generate high-temperature steam. Is converted to The high-temperature steam generated in the heat exchanger 4 passes through the steam passage 19 and is sent to the exhaust pipe 12 with the steam flow controlled by the control valve 6. The high-temperature steam sent to the exhaust pipe 12 is mixed with the exhaust gas from the combustion chamber 2 and acts on the turbine 20 of the turbocharger 3 to increase the driving force of the turbine 20. In other words, the water heated by the heat exchanger 5 is further heated by the heat exchanger 4 to become high-temperature steam, and the steam energy is given to the turbine 20 to constitute a part of an energy recovery device. In addition, the controller 10 consumes the power generated by the generator operation of the generator / motor 22 with the auxiliary machine,
Alternatively, control for storing power in the battery is performed. Controller 1
0 indicates that the generator / motor 22 is operated as a motor, and the compressor 2 is operated using the electric power stored in the battery.
The control for supercharging or the like by the control unit 1 is performed.

Although the heat exchangers 4, 5, and 37 do not show their structures in detail, they have, for example, a structure in which the heat contact area of a porous ceramic member or the like is increased. Further, the electric power generated by the electric generator / motor 22 is stored in a battery or consumed for driving an auxiliary machine.
In the engine 1, the water heated by the heat exchangers 4 and 5 is converted into high-temperature steam, which drives the turbine 20 and is discharged from the exhaust pipe 15 while being included in the exhaust gas. Since it is separated from the steam and the intake air at 8 and 11 and discharged to the outside from the drain pipes 33 and 34, this Rankine cycle does not have a condenser and the structure is simplified.

Next, another embodiment of the engine provided with the fuel reformer according to the present invention will be described with reference to FIG.
The embodiment shown in FIG. 2 has the same configuration and the same function except that the fuel reformer 35 is arranged upstream of the turbocharger 3 as compared with the embodiment shown in FIG. Therefore, the same reference numerals are given to the same components, and the duplicate description will be omitted here. In this embodiment, the fuel reformer 35 is first disposed in the exhaust pipe 12 through which the exhaust gas discharged from the engine 1 passes, and the turbocharger 3 is disposed in the exhaust pipe 13 downstream. Before the exhaust gas drives the turbocharger 3, the exhaust gas thermal energy can most effectively affect the pyrolysis of the gaseous fuel.

[0037]

Since the engine provided with the fuel reformer according to the present invention is constructed as described above, the fuel reformer utilizes the heat energy of the exhaust gas driven by the turbine by the turbocharger. The thermal efficiency is improved by reforming the fuel, and the thermal energy of the exhaust gas recovered by the heat exchanger is recovered by driving the turbine to improve the thermal efficiency. Part of the exhaust gas is converted into EGR gas to the combustion chamber. Supply and NO _X
The occurrence of is reduced. That is, in this engine, a part of the exhaust gas from which the heat energy is recovered in the first heat exchanger is supercharged by the compressor as EGR gas, and the intake air composed of the EGR gas and the intake air is further supplied to the second heat exchanger. Further cooled,
Can supply a large amount of EGR gas into the combustion chamber, it is possible to reduce the occurrence of NO _X. In this engine, particularly, a large amount of EGR gas is supplied to the combustion chamber, so that even if the fuel has a high compression ratio, diesel ignition can be performed, engine performance can be improved, and generation of NO _X can be suppressed. Moreover, in this engine, since CO ₂ in the exhaust gas is separated by the CO ₂ separation device and used for reforming the gaseous fuel, the C
O ₂ is reduced to about 1/3 as compared with a general engine.

The water heated by the first and second heat exchangers is converted into high-temperature steam and recovered as energy for driving the turbocharger turbine, and the driving force of the turbine is generated by the electric power generated by the generator / motor. And is consumed to operate the compressor, the exhaust gas energy is effectively recovered and the thermal efficiency can be improved. Further, in this engine, an EGR gas flow rate is controlled by a controller in an operation state of the engine, and a water flow rate sent to the second heat exchanger is controlled in accordance with the exhaust gas temperature, thereby providing an extremely appropriate energy recovery device. Can be. Further, in this engine, since the heat energy of the exhaust gas is recovered by the fuel reformer and the heat exchanger, there is no loss due to the back pressure generated by the conventional recovery turbine, and the heat of the exhaust gas is effectively reduced. Since energy is recovered, fuel efficiency can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of an engine provided with a fuel reformer according to the present invention.

FIG. 2 is a schematic explanatory view showing another embodiment of the engine provided with the fuel reforming apparatus according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Engine 2 Combustion chamber 3 Turbocharger 4 Heat exchanger (1st heat exchanger) 5 Heat exchanger (2nd heat exchanger) 6 Control valve 7 EGR control valve 8, 11 Water separation device 9 Water pump 10 Controller 12, 13, 14, 15 exhaust pipe 16 EGR gas passage 17,18,25 intake pipe 19 steam passage 20 turbine 21 compressor 22 motor-generator 24,26,43 water passage 35 fuel reformer 36 CO ₂ separation device 37 heat exchanger (Third heat exchanger) 39 mixing chamber 40 fuel tank 41 CO ₂ supply pipe 42, 44, 45 fuel supply pipe 46 fuel injection nozzle

Claims (10)

[Claims] An exhaust gas through which exhaust gas discharged from a combustion chamber flows.
A turbocharger installed in the trachea, said turbocharger
Exhaust gas thermal energy installed downstream of the turbine
Fuel reformer that reforms gas fuel by pyrolysis using gas
, A first heat exchanger provided downstream of the fuel reformer
From the exhaust gas passing through_TwoTo separate CO_TwoMinute
Hot water supplied to the separation device and the first heat exchanger.
-EGR sent out from the compressor of the booster
Utilizes thermal energy from the compression of gas and intake air to produce water
Heat from the second heat exchanger and the fuel reformer.
Fuel supply device for supplying the reformed fuel discharged to the combustion chamber
And the CO_TwoCO separated by the separation device_TwoWhen
The water heated by the second heat exchanger and the fuel reformer
To the gas fuel CH_FourTo CO_TwoAnd H_TwoExistence with O
CO and H under the _TwoReforming consisting of pyrolysis into coal
Engine with equipment. 2. The fuel reformer has a structure in which CH ₄ is CO _2.
Provided with for thermally decomposed under CO and H ₂ in the presence of H ₂ O, Ru, Pt, a fuel reforming apparatus according to claim 1 which consists of a metal catalyst such as Ni are accommodated Engine. 3. The fuel reformer according to claim 1, further comprising an EGR device for feeding a part of the exhaust gas passing through the CO ₂ separation device to the combustion chamber by a compressor of the turbocharger. With an engine. 4. The engine provided with the fuel reforming apparatus according to claim 1, wherein the steam generated in the first heat exchanger is sent to the turbine to increase the driving force of the turbine. 5. A dry EGR gas passing through the water separation device, further comprising a water separation device for eliminating water droplets generated by colliding the exhaust gas passing through the CO ₂ separation device with intake air from an air cleaner. An engine provided with a fuel reforming apparatus according to claim 1, comprising supplying air and intake air to the combustion chamber by a compressor of the turbocharger. 6. A water pump that supplies the water to the second heat exchanger and supplies hot water heated by the second heat exchanger to the first heat exchanger and the fuel reformer. An engine provided with the fuel reformer according to claim 1, comprising: 7. A separate water separator for separating moisture from intake air supplied from the second heat exchanger to the combustion chamber.
The engine provided with the energy recovery device according to claim 1, wherein the engine is provided in an intake pipe downstream of the heat exchanger. 8. A third heat exchanger is provided in a water passage from the second heat exchanger to the fuel reformer, and reformed fuel from the fuel reformer is supplied by the third heat exchanger. 2. The fuel reformer according to claim 1, wherein the fuel is cooled to an appropriate temperature and supplied to the combustion chamber, and the water from the second heat exchanger is heated by the third heat exchanger and sent to the fuel reformer. With an energy recovery device. 9. The engine according to claim 1, wherein the turbocharger includes a generator / motor provided on a shaft connecting the turbine and the compressor. 10. A fuel reformer for thermally decomposing and reforming gaseous fuel using exhaust gas thermal energy provided in an exhaust pipe through which exhaust gas discharged from a combustion chamber having an adiabatic structure is provided. turbocharger with a generator provided on the downstream of the quality system, CO ₂ separating device for separating CO ₂ from the exhaust gas passing through the first heat exchanger provided on the downstream of the turbocharger, and A second heat exchanger for heating the hot water to be supplied to the first heat exchanger by using heat energy generated by compression of EGR gas and intake air sent from a compressor of the turbocharger, and the fuel reformer reformed fuel comprises a fuel supply device for supplying to the combustion chamber, the CO ₂ separation the fuel reformer has been the water heating are separated in the apparatus was CO ₂ and in the second heat exchanger fed from Supply to , Engine with a fuel reforming apparatus comprising a thermal decomposition in under CO and H ₂ in the presence of a CH ₄ gas fuel and CO ₂ and H ₂ O.