JP2003239809A - Gas engine provided with fuel reforming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas engine reforming natural gas into reformed fuel, improving heat efficiency, and ensuring ignition and combustion in an auxiliary chamber. <P>SOLUTION: In the gas engine, an auxiliary chamber control valve 8 is arranged in a communication opening 27 communicating a main chamber 1 with the auxiliary chamber 2, and the natural gas is reformed into the reformed fuel of H<SB>2</SB>and CO by the fuel reforming device 15 arranged on an exhaust pipe 30. A reformed fuel valve 17 is provided in an intake manifold 16 of an intake pipe, and the reformed fuel is fed to the main chamber 1 in a suction stroke. A natural gas fuel valve 3 is arranged in the auxiliary chamber 2 and the natural gas is fed to the auxiliary chamber 2 from the suction stroke to a compression stroke. In a latter half of the compression stroke, the auxiliary chamber control valve 8 is opened, a mixture of air and the reformed fuel is blown into the auxiliary chamber 2 from the main chamber 1, and a glow plug 18 is provided in an upper part of the auxiliary chamber 2 igniting and burning the natural gas in the auxiliary chamber 2 for assisting ignition and combustion of the natural gas. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas engine equipped with a fuel reformer for reforming natural gas into reformed fuel.

[0002]

2. Description of the Related Art Improving the thermal efficiency of an engine is indispensable for solving major global problems such as global warming and exhaustion of energy resources. Since these problems could not be solved as an extension of the conventional technology, fuel reforming was considered as a new method. In order to improve the thermal efficiency, it suffices to increase the power of the effective work generated from the engine, but the thermal efficiency of the diesel engine with the largest compression ratio at present is about 40-48%,
No further improvement is possible. However, since most of the heat is dissipated in the exhaust gas and cooling water, a method of recovering these heats has been considered, but it was possible to improve the thermal efficiency by several percent, but it was impossible to exceed it.

Conventionally, a gas engine using natural gas as a main fuel has been developed as a cogeneration system. The cogeneration system takes out as electric energy from a generator driven by engine power, heats the exhaust gas energy with a heat exchanger to heat water, and uses the hot water for hot water supply. Conventionally, as an engine using natural gas as a fuel, for example, JP-A-6-108865 and JP-A-6-10.
There is one disclosed in Japanese Patent No. 1495.

In the cogeneration type gas engine disclosed in Japanese Patent Laid-Open No. 6-108865, the exhaust gas temperature is lowered through a turbocharger, an energy recovery device and a steam generator, and the low temperature exhaust gas is exhausted.
It is used for GR to reduce NO _X , exhaust gas from a heat shield type gas engine drives a turbocharger, and exhaust gas from the turbocharger drives an energy recovery device equipped with a generator. The cogeneration gas engine sends exhaust gas from an energy recovery device to a steam generator of a heat exchanger, converts water into steam by the steam generator, and drives the steam turbine with the steam to recover electric energy. To do.

As a gas engine using a fuel obtained by reforming natural gas, for example, one disclosed in Japanese Patent Laid-Open No. 11-93777 is known. The natural gas reforming apparatus disclosed in this publication uses CH ₄ which is a main component of natural gas as C
Pyrolysis of O and H ₂ into reformed fuel improves thermal efficiency and reduces the CO ₂ content in the exhaust gas released by using CO ₂ in the exhaust gas for pyrolysis, thereby reducing the generation of NO _x . It suppresses. The natural gas reformer has an exhaust gas passage body that forms an exhaust gas passage in an exhaust gas pipe, a gas fuel case in which gas fuel flows outside the exhaust gas pipe, and a gas fuel passage in the gas fuel case. A porous member made of porous ceramics to be formed is arranged, and the surface of the porous member is coated with a catalyst having an action of converting CH ₄ and CO ₂ into reformed fuels of CO and H ₂ . A heat insulating material is arranged on the outer circumference.

Further, as a heat exchange device, Japanese Patent Laid-Open No. 11-6
There is one disclosed in Japanese Patent No. 601. The heat exchange device includes a first-stage heat exchanger and a second-stage heat exchanger provided in an exhaust passage that heats steam with exhaust gas from the engine. The first-stage heat exchanger is composed of a steam passage arranged in the first casing, through which steam flows, and an exhaust gas passage arranged in the steam passage, in which exhaust gas flows. The second-stage heat exchanger has a water / steam passage arranged in the second casing provided below the first casing and capable of storing water, and an exhaust gas arranged around the water / steam passage for flowing exhaust gas. It is composed of a gas passage. A porous ceramic member is arranged in each passage.

Further, in Japanese Patent Laid-Open No. 11-93777,
Discloses a heat exchanger applied to a natural gas reformer
Has been done. The natural gas reformer is a
CH_FourCO and H₂Which is pyrolyzed into the reformed fuel of
To improve thermal efficiency and reduce CO in exhaust gas.₂The heat
CO in exhaust gas emitted when used for solution₂Reduced content
To do. Natural gas reformer is an exhaust gas pipe
The exhaust gas passage body that forms the exhaust gas passage is placed inside,
A gas fuel case in which gas fuel flows outside the exhaust gas pipe
Gas to form a gas fuel passage in the gas fuel case.
A porous member made of porous ceramics is
CH on the surface of the porous member_FourAnd CO₂CO and H ₂Reformed combustion of
Coated with a catalyst that has the function of converting to gas
A heat insulating material is arranged on the outer circumference of the material pipe.

[0008]

[Problems to be Solved by the Invention] However, natural gas
Because the exhaust gas is used as fuel for the engine,
Technical idea of reforming natural gas using energy
, Which is being researched and developed by the present inventor,
Combustion tests show that in the case of natural gas it ignites
Is extremely difficult, and problems such as startability are extremely difficult.
I understood. Reforming natural gas and using reformed gas as fuel
When used as a fuel, the reformed fuel is CO and H₂Next to that
Calorific value increases by about 30% but reforming does not proceed completely
It may be a mixed gas, and its properties are not always stable.
I found it wasn't. Also, gas that uses natural gas as fuel
In the engine, the combustion chamber is made of a material such as ceramics to provide a heat shield structure.
Structure, the compression temperature of air is self-ignition of natural gas.
Since the temperature rises above the temperature, the igniter becomes unnecessary, but
A locking occurs. Therefore, it is an extremely dilute mixture and O
₂Introduce EGR and air to keep concentration low
Introduce fuel in addition to the main combustion chamber to create a rich mixture
A sub-combustion chamber is provided, and the main combustion chamber and sub-combustion chamber are communicated with each other.
A control valve is installed on the
Providing a highly efficient engine for cogeneration
Can be offered. According to this structure,
Exhaust gas of engine when the combustion chamber is structured as a heat shield
Moreover, the temperature rises to over 850 ° C. Heat from hot exhaust gases
Recovers energy to improve engine thermal efficiency
Can be improved.

By the way, the main component of natural gas is meta.
CH_FourAnd has a large amount of heat generation, and is present in nature in large numbers
Therefore, it is expected as an alternative fuel for oil in the future. Well
CH_FourCO₂Pyrolysis via a catalyst in the presence of
If you do, CH_FourIs CO and H ₂Is converted to
H₂The total calorific value of_FourMore than the calorific value of
That is 1.3 times. Therefore, the heat shield type gas engine
CH of the heat energy of the warm exhaust gas_FourUsed for the thermal decomposition of
By reforming natural gas into reformed fuel by
Increase the heat generation of the fuel, improve the thermal efficiency of the engine,
CO as well as resources₂Can suppress the discharge of
It

However, when CH _{4 in} natural gas is changed to CO
_In a natural gas reformer that reforms H ₂ and CO by the heat energy of exhaust gas due to the presence of ₂ , when CO ₂ separated from exhaust gas is used, O ₂ is contained in the separated gas containing CO _2. If included, O ₂ reacts with H ₂ and CO in the catalyst device in the natural gas reformer,
In some cases, there is a risk of reaction explosion. Therefore, it is necessary to reduce O ₂ contained in the separated gas containing CO ₂ separated from the exhaust gas sent to the natural gas reformer as much as possible.

Generally emitted from diesel engines
The exhaust gas is₂Is 75%, CO
₂Is 15% and O₂Is about 10%, but this is not always
O, not a ratio like₂May be included
It In addition, exhaust gas CO₂CO of separator₂Through a separation membrane
CO separated from exhaust gas by₂including
The separation gas is CO₂Is 90%, N₂Is 8% and O₂Is 2
%, Which would normally be the separation gas for such components.
The gas into the natural gas reforming unit
But CO with high exhaust gas concentration₂Abnormality of separation membrane
It is easy to occur, O₂Occurs when 5% or more is included
Sometimes. Therefore, O of 5% or more₂Separation gas containing
Is sent to the natural gas reformer,
H generated ₂And CO in the separated gas are O₂And reaction explosion
However, a very dangerous situation occurs. Struggling as above
Using the reformed fuel generated by
Even if supplied, if the reformed fuel is not completely burned,
The performance of the engine cannot be improved.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to improve the performance by effectively combusting a reformed fuel obtained by reforming natural gas in an engine. Regarding a gas engine that supplies natural gas and its reformed fuel as fuel to the engine, a fuel reformer that reforms the natural gas is provided near the outlet of the exhaust pipe by providing a sub-combustion chamber above the cylinder of the main combustion chamber. Provided is a gas engine equipped with a fuel reformer for premixed compression diesel combustion in which a natural gas before reforming is supplied to a sub-combustion chamber and reformed fuel and air are supplied to an intake pipe. Is.

According to the present invention, the cylinder head mounted on the cylinder block, the piston reciprocating in the cylinder formed on the cylinder block side, the main combustion chamber formed on the piston side, and the cylinder head are provided. A sub-combustion chamber, a sub-chamber control valve arranged at a communication port that connects the main combustion chamber and the sub-combustion chamber, and natural gas using the thermal energy and CO ₂ of exhaust gas discharged from the main combustion chamber Reformer for reforming hydrogen into H ₂ and CO, a reforming fuel valve provided in a reforming fuel passage arranged in the intake pipe, and a natural gas supply passage for supplying natural gas to the auxiliary combustion chamber The sub-chamber control valve is opened in the latter half of the compression stroke to blow a lean mixture of air and reformed fuel from the main combustion chamber into the sub-combustion chamber. The natural gas in the combustion chamber The present invention relates to a gas engine which comprises igniting and burning a gas.

In this gas engine, a glow plug is arranged above the auxiliary combustion chamber facing the auxiliary chamber control valve.

Since the natural gas valve supplies the natural gas to the auxiliary combustion chamber having a volume ratio of 5 to 20%, the auxiliary chamber control valve is closed from the latter half of the intake stroke to the first half of the compression stroke. Open at the time.

The reforming fuel valve is opened during the intake stroke to supply the reforming fuel to the main combustion chamber.

The sub-chamber control valve is set to open in the latter half of the compression stroke and close in the latter half of the exhaust stroke.

The portions of the sub-combustion chamber and the sub-chamber control valve that come into contact with the combustion gas are coated with corrosion-resistant ceramics such as zirconia.

The fuel reformer is a heat exchanger for recovering the thermal energy of the exhaust gas, and CO ₂ in the exhaust gas.
An adsorbing device for adsorbing hydrogen and a catalytic device for reforming the natural gas into the reformed fuel are provided.

The fuel reformer is provided with a fuel reforming control valve for sequentially supplying the exhaust gas, the natural gas and the steam to the compartments of the rotary container.

The fuel reformer has a cylindrical rotary container which is rotatably supported by a cylindrical housing and whose inside is divided into a plurality of compartments by a partition plate in the rotational direction. Each of the compartments contains a metal porous body carrying an adsorbent, a catalyst, etc., and an exhaust pipe, a steam pipe and a natural gas pipe are connected to the inlet side opening and the outlet side opening of the housing, respectively. .

The fuel reformer includes a fuel reforming control valve for sequentially supplying the exhaust gas from the exhaust pipe, the steam from the steam pipe and the natural gas from the natural gas pipe to the rotary container. ing.

The gas engine equipped with this fuel reforming device is constructed as described above, and the properties of the reformed fuel are not always fixed, and the ignition temperature changes and the air-fuel mixture in the main combustion chamber itself changes. Since a lean mixture is used to prevent ignition, a control valve is placed at the communication port that connects the main combustion chamber and the auxiliary combustion chamber, and the auxiliary combustion chamber is filled with natural gas fuel. When the reformed fuel is supplied and the control valve is opened in the latter half of the compression stroke to send the hot compressed gas into the sub-combustion chamber, the rich mixture comes into contact with the glow plug at the back of the sub-combustion chamber and ignites, resulting in the core of combustion. And the ignition progresses steadily. Further, the combustion in the sub-combustion chamber is configured so that ignition is generated by the heat source of the glow plug, and it seems that little heat is transferred to and from the wall surfaces of the sub-combustion chamber and the sub-chamber control valve that come into contact with the combustion gas. Ceramics such as zirconia are coated. At this time, if the reformed fuel and air with unstable combustion are supplied to the main combustion chamber and the natural gas whose properties such as ignition are determined are supplied to the sub combustion chamber, the ignition conditions in the sub combustion chamber Since it is clear, the opening of the control valve can be made constant and combustion can be steadily performed in the auxiliary combustion chamber. Further, the amount of fuel supplied to the sub-combustion chamber can be changed by changing the gas pressure or the gas feed time, so that the fuel supply amount in the sub-combustion chamber can be changed sequentially.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a gas engine equipped with a fuel reforming apparatus according to the present invention will be described below with reference to the drawings. A gas engine equipped with a fuel reforming apparatus according to the present invention uses natural gas as a fuel, and uses natural gas, that is, CH ₄ as its main component, in the exhaust gas while utilizing the thermal energy of the exhaust gas of the engine. CO ₂ contained in
Is used to reform into a reformed fuel composed of CO and H ₂ ,
It increases the heat quantity of the fuel and improves the thermal efficiency of the engine, and is preferably applied as an engine for cogeneration systems, automobiles, ships and the like.

In this gas engine, the combustion chamber has a heat shield structure.
Configured and driven by a diesel cycle fueled by natural gas
It is driven and mainly reciprocates in the cylinder 4.
The main combustion chamber provided on the moving piston 5 side, that is, the main chamber 1 and the cylinder
Has a sub-combustion chamber or sub-chamber 2 provided in
The sub-chamber control valve 8 is provided at the communication port 27 that connects the chamber 1 and the sub-chamber 2 to each other.
An intake pipe 33 for supplying intake air and an intake manifold are provided in the main chamber 1.
CO and H obtained by reforming natural gas through the nib 16₂Or
The reformed fuel and air are supplied to the sub chamber 2 and natural gas is supplied.
Is directly supplied and the auxiliary chamber control valve 8 is opened at the end of the compression stroke.
Then, a mixture of air and reformed fuel is introduced from the main chamber 1 into the sub chamber 2.
Blowing the natural gas supplied to the sub chamber 2
It is ignited and burned with the help of the lug 18. This gas
Immediately after the exhaust pipe 30, the engine heats the exhaust pipe 30.
The fuel reformer 15 consisting of a heat exchanger that absorbs energy is
The fuel reformer 15 is provided with
CO ₂Zeolite that absorbs (zeolite) and / or
Is an adsorption device for activated carbon and Pt, R for reforming natural gas
u, Ni, Pd, Al₂O₃And a catalytic device consisting of
It has been burned.

This gas engine, as shown in FIG.
The cylinder head 12 is fixed to the cylinder block 11 via the intermediate head 13, and a sub-chamber structure 21 that forms the sub-chamber 2 of the heat shield structure is arranged in a hole formed in the cylinder head 12. The hole 50 formed in the intermediate head 13 fixed to the cylinder head 12, that is, the cylinder head 1.
A combustion chamber member 14 that forms the main chamber 1 of the heat shield structure is disposed in the cavity of No. 2. This gas engine has a cylinder liner 3 in the hole formed in the cylinder block 11.
4 are fitted to each other, and the piston 5 reciprocates in the cylinder 4 formed in the cylinder liner 34. A communication port 27 that connects the main chamber 1 and the sub chamber 2 is formed in the sub chamber structure 21.

Further, as shown in FIG. 2, the combustion chamber member 14
The sub-chamber control valve 8 for opening and closing the communication port 27 is arranged in the communication port 27 formed in the above. The sub-chamber structure 21 is
The sub chamber control valve 8 is arranged so as to penetrate the sub chamber 2, and a seal ring 24 is arranged on the stem of the sub chamber control valve 8 to seal the sub chamber 2. The sub chamber control valve 8 is, for example, the valve mechanism 2
The valve is opened by 0 and closed by the return spring 23. A natural gas supply port 28 connected to the natural gas passage 22 is formed in an upper portion of the sub chamber 2, and a natural gas valve 3 which is driven to open and close by a cam is arranged in the natural gas supply port 28. Therefore, the natural gas supply port 28 is configured to be opened and closed by the natural gas valve 3. Further, a glow plug 18 is arranged at an upper portion of the sub chamber 2 opposite to the communication port 27. The glow plug 18 has a function of assisting the ignition and combustion of the natural gas, and is provided in the upper portion or the inner portion of the sub-chamber 2, so that the natural gas supplied into the sub-chamber 2 remains from the sub-chamber 2 due to the ignition and combustion. It is surely ejected into the main chamber 1 without performing.

This gas engine has a cylinder head 12
An intake port 9 and an exhaust port 10 are formed in the. The combustion chamber member 14 is composed of a liner upper portion 35 and a head lower surface portion 36 which form a part of the cylinder 4. Ports corresponding to the intake port 9 and the exhaust port 10 formed in the cylinder head 12 are formed in the head lower surface portion 36, and although not shown, an exhaust valve and an intake valve are arranged in the port. A heat shield air layer 31 is formed between the cavity of the cylinder head 12 and the outer surface of the combustion chamber member 14, and a heat shield air layer 31 is formed so that the main chamber 1 has a heat shield structure. Further, a heat shield air layer 3 is provided between the wall surface of the cavity of the cylinder head 12 and the outer surface of the sub chamber structure 21.
2 is formed, and the sub chamber 2 has a heat shield structure. The piston 5 is composed of a piston head 6 made of ceramics such as silicon nitride having excellent heat resistance, and a piston skirt 37 fixed to the piston head 6 with a coupling ring. The piston head 6 has a main chamber 1 formed of a concave cavity 7. A heat-shielding air layer 38 is formed between the piston head 6 and the piston skirt 37, and the main chamber 1 has a heat-shielding structure.

The sub-chamber structure 21 is fitted into the cavity of the cylinder head 12, specifically, the hole 50 of the intermediate head 13 which is a part of the cylinder head, with a gasket 62 interposed if necessary. Has been done. The lower portion of the sub-chamber structure 21 is fitted into the hole 39 formed in the combustion chamber member 14, and the communication port 27 formed in the sub-chamber structure 21 has the main chamber 1
Communicates with the sub chamber 2. Therefore, the combustion chamber structure is composed of the sub chamber structure 21 forming the sub chamber 2 and the combustion chamber member 14 forming the main chamber 1, and the sub chamber structure 21 is formed by the combustion chamber member 14.
Is arranged in a hole 39 formed in the center of the combustion chamber member 14, and a communication port 27 formed in the sub chamber structure 21 connects the main chamber 1 and the sub chamber 2 to each other in the center of the combustion chamber member 14. Is formed in. Therefore, the sub-chamber 2 formed in the sub-chamber structure 21
Are located approximately in the center of the cylinder axis. Also,
A gas fuel passage 22 is formed in the cylinder head 12,
It communicates with the natural gas supply port 28 formed in the sub chamber structure 21.

Natural gas as a fuel is stored in a fuel supply source such as a tank provided at an appropriate place. The natural gas fuel of the gas fuel supply source is pressurized to, for example, 5 to 7 kg / cm ² by the operation of the fuel transfer fuel pump, and the pressurized natural gas fuel is supplied to the gas fuel passage 22 through the fuel supply passage. Sent in. As for the natural gas fuel in the gas fuel passage 22, the natural gas valve is the natural gas supply port 2
It is supplied to the sub chamber 2 by opening 8.

In this gas engine, the piston head 6 forming the main chamber 1, the sub-chamber structure 21 forming the sub-chamber 2, and the cylinder liner 34 are made of, for example, silicon nitride, silicon carbide, sialon or the like having excellent heat resistance. It is made of ceramics. In addition, since the piston head 6 and the sub-chamber structure 21 become hot, the sub-chamber control valve 8 arranged at the communication port 27 is made of a heat-resistant metal having high temperature strength and excellent in heat resistance, ceramics such as silicon nitride and silicon carbide. It is manufactured.

In this gas engine, the fuel reformer 15
Is arranged in the exhaust pipe 30 in the immediate vicinity of the exhaust port 9, and is configured to utilize the thermal energy of the exhaust gas. The reforming fuel passage 40 is connected to the intake manifold 16 communicating with the intake port 10, and the reforming fuel passage 4 is connected.
Reforming fuel supply port 29 in which 0 opens in the intake manifold 16
A reforming fuel valve 17 which is an electromagnetic valve is arranged in the. The reforming fuel valve 17 is configured to be opened and closed according to a command from the controller 25, and to be opened and closed in synchronization with the intake valve actuator 26. Therefore, the reformed fuel obtained by reforming the natural gas by the fuel reformer 15 flows from the fuel reformer 15 through the reforming fuel passage 40 to the main chamber 1 through the intake manifold 16 by opening the reforming fuel valve 17 together with air. Is configured to be supplied. That is, the natural gas accommodated in the fuel supply source is sent to the fuel reforming device 15 arranged in the exhaust pipe 30, receives the heat energy of the exhaust gas, and is reformed into reformed fuel of H ₂ and CO. The fuel is supplied to the main chamber 1 through the fuel supply passage by the fuel pump.

This gas engine is constructed as described above and is operated as follows. As shown in FIG. 4, this gas engine is operated by sequentially repeating four strokes of an exhaust stroke, an intake stroke, a compression stroke and an expansion stroke. In this gas engine, the reformed fuel valve 17 opens the reformed fuel supply port 29 that opens to the intake pipe 33 and the intake manifold 16 from the beginning to the latter half of the intake stroke when the intake valve opens the intake port 6 to the main chamber 1. Then, the reformed fuel is supplied from the reformed fuel device 15 into the intake manifold 16 together with the intake air into the main chamber 1. On the other hand, from the latter half of the intake stroke to the first half of the compression stroke in which the intake valve closed the intake port 6, the natural gas supply port 28 is passed through the natural gas passage 22.
The natural gas valve 3 is opened, and natural gas is supplied to the sub chamber 2. The ratio of the fuel supplied to the main chamber 1 and the sub chamber 2 is, for example, about 5 to 20% of the total amount of the fuel flow rate of the natural gas supplied to the sub chamber 2 and supplied to the main chamber 1. The supplied amount of the reformed fuel is about 95 to 80% of the total amount of the fuel flow rate, and is a lean air-fuel mixture that does not self-ignite in the main chamber 1.

In this gas engine, at the end of the compression stroke, the sub-chamber control valve 8 opens the communication port 27, and the compressed mixture of reformed fuel and air is compressed from the main chamber 1 into the sub-chamber. It flows into the chamber 2 and, as shown in the pressure diagram shown in FIG.
The natural gas in the sub chamber 2 becomes high pressure and high temperature, and the glow plug 1
With the help of 8, the sub-chamber 2 is ignited and burned, the pressure in the sub-chamber 2 rises at once, and the combustion flame from the sub-chamber 2 to the main chamber 1 passes through the communication port 27 and natural gas remains in the sub-chamber 2. The flame is blown out and the whole amount is ejected. Then, the combustion propagates to the mixture of reformed fuel and air in the main chamber 1 to complete the secondary combustion in a short time to improve the thermal efficiency and shift to the expansion stroke. Work by pushing down the piston 5. In the sub chamber control valve 8, the exhaust valve opens the exhaust port 10 and shifts to the exhaust stroke, and closes the communication port 27 in the latter half of the exhaust stroke. Next, the exhaust valve closes the exhaust port 10, the intake valve opens the intake port 9 and shifts to the intake stroke, and the engine is driven by repeating these strokes.

Next, an example of the fuel reformer 15 will be described with reference to FIGS. 5 and 6. The fuel reformer 15 is mainly a control valve device for sequentially pumping exhaust gas, steam, natural gas, and air, that is, an exhaust gas valve 66, a steam valve 6
7, a natural gas fuel valve 68 and an air valve 65 are provided. The fuel reformer 15 has a plurality of inlet-side openings 5 on one end surface.
2 and a cylindrical housing 41 having a plurality of outlet-side openings 53 formed on the other end surface thereof, which is rotatably supported by the housing 41 and whose inside is divided by a partition plate 49 into a plurality of compartments 55 in the rotational direction. It has a rotary container 42 in the shape of a circle. In the fuel reformer 15, the exhaust pipe 30, the water vapor pipe 45, the natural gas pipe 46 for introducing the natural gas, and the air introduction pipe 64 are sealed in the inlet side opening 52 of the housing 41 via the seal member 59. The exhaust pipe 30, the steam pipe 45, the reforming fuel pipe 40 for sending out the reformed gas, and the air introduction pipe 64 are connected to the outlet side opening 53 of the housing 41 in a sealed state via the seal member 59. Has been done. Further, the air introduction pipe 64 on the outlet side and the reformed fuel pipe 40 are connected and communicate with the intake pipe 33.
The natural gas pipe 46 and the reformed fuel passage 40 are positioned so as to correspond to the longitudinal direction. In particular, each of the compartments 55 of the rotary container 42 accommodates the metal porous body 43 and has a function of reforming natural gas.

The rotating container 42 includes a housing 41 and bearings 5.
It is fixed to a rotary shaft 54 which is rotatably attached via 6. Inlet 4 formed on one end surface of the rotary container 42
7 is positioned so that it can be aligned with the inlet side opening 52 of the housing 41. Also, the rotating container 4
The outlet 48 formed on the other end surface of the housing 2 is positioned so that it can be aligned with the outlet side opening 53 of the housing 41. The fuel pipe is the inlet side opening 5 of the housing 41
A natural gas pipe 46 for introducing the natural gas connected to 2;
The reformed fuel passage 40 for sending out reformed fuel is connected to the outlet side opening 53 of the housing 41.
6 and the reformed fuel passage 40 are positioned corresponding to the longitudinal direction of the rotary container 42. The rotary container 42 is rotatably supported by a base 57 in a vacuum layer 58 formed in the housing 41 via a bearing 56. Further, the rotary container 42 is rotationally driven by a motor 51 whose rotational speed is controlled by a command from the controller 25.

The metal porous body 43 is made of a metal material such as Ni, Cr and Fe. The surface of the metal porous body 43 is coated with alumina, and the surface of the alumina is coated with zeolite powder that captures CO ₂ in the exhaust gas. Furthermore, on the surface of the zeolite powder, Pt, Ru, Ni, Pd (palladium), Al, which serves as a catalyst when thermally decomposing natural gas into reformed fuel of H ₂ and CO, is formed.
A catalyst layer such as ₂ O ₃ is arranged.

In response to a command from the controller 25, the rotary container 42
A motor 51 that can variably control the rotation, stop, intermittent rotation, and rotation speed of the rotary container 42 is attached to the. In the fuel reformer 15, exhaust gas is introduced into the compartment 55 of the rotary container 42 through the exhaust pipe 30, CO ₂ in the exhaust gas is adsorbed by the zeolite on the surface of the metal porous body 43, and then the exhaust gas Exhaust gas containing oxygen is discharged from the compartment 55 by introducing steam vaporized by heat energy into the compartment 55 through the steam pipe 45, and then the natural gas introduced into the compartment 55 through the natural gas pipe 46 is zeolite. And / or CO ₂ adsorbed by activated carbon and in the presence of water vapor,
It reforms natural gas by reacting it with CO and H ₂ .

The rotary container 42 is formed in a cylindrical body such as a cylinder. The rotary container 42 is partitioned by a plurality of partition plates 49 extending in the radial direction into compartments 55 that form a plurality of spaces 61. The spaces 61 are filled with metal porous bodies 43 made of heat-resistant metal. ing. When the rotary container 42 rotates in the housing 41, the reformed fuel device 15 has an inlet 4 formed in the rotary container 42.
7 and the outlet 48 sequentially pass through the inlet side opening 52 and the outlet side opening 53 of the housing 41 to which the exhaust pipe 30, the steam pipe 45, the natural gas pipe 46, and the air introduction pipe 64 are connected. . The controller 25 places the rotary vessel 42 in an optimal operating state for reforming natural gas,
An operation command is issued to the motor 51 to control the rotary operation of the rotary container 42.
It is possible to control stop, continuous rotation, or intermittent rotation.

Since the fuel reformer 15 applied to this gas engine is constructed as described above, the exhaust gas is introduced into the compartment 55 of the rotary container 42 through the exhaust pipe 30, and the CO in the exhaust gas is reduced. ₂ is adsorbed by the zeolite and / or activated carbon on the surface of the porous metal body 43, and then the steam vaporized by the heat energy of the exhaust gas is discharged into the compartment 5
Fed to 5, the O ₂ remaining in compartment 55 is removed by water vapor, where natural gas is fed into the compartment 55, of CO ₂ in the natural gas CH ₄ are trapped in a zeolite and / or activated carbon In the presence of CO and H ₂ reformed fuel and CH ₄ and H ₂ O to reformed CO and H ₂ reformed fuel, thereby converting all natural gas to CO The reformed fuel is reacted with H ₂ and reformed, and air is sent from the air introduction pipe 64 to the compartment 55 to supply the reformed fuel together with the air to the engine through the intake pipe 33 and then the intake manifold 16. is there.

The fuel reforming apparatus applicable to this gas engine is not limited to the above-mentioned configuration, but may be of a simple structure as shown in FIGS. 7 and 8. 7 and 8 showing the simplified fuel reformer 15S, the same members as those of the fuel reformer 15 shown in FIGS. 5 and 6 are designated by the same reference numerals. The simple fuel reformer 15S is
An exhaust pipe 30, a natural gas pipe 46 for introducing natural gas, a steam pipe 45, and an air introduction pipe 64, which are connected to each other in a sealed state via a seal member 59, are connected to the inlet side opening 52 of the housing 41, and Exhaust pipe 3 connected to the outlet side opening 53 through a seal member 59 in a sealed state.
0, the reformed fuel passage 40 for sending out reformed gas, and the air introduction pipe 64 are connected. In addition, the compartment 55 of the rotary container 42
Control valve device for sequentially pumping exhaust gas, natural gas, water vapor and air to the exhaust gas, ie, exhaust gas valve 66, natural gas fuel valve 6
8, a water vapor valve 67 and an air valve 65 are provided. In the simplified fuel reformer 15S, a motor 51 capable of variably controlling rotation, stop, intermittent rotation, and rotation speed of the rotary container 42 is attached to the rotary container 42 in response to a command from the controller 25. ing.

Since the simple fuel reformer 15S is constructed as described above, the exhaust gas is introduced into the compartment 55 of the rotary container 42 through the exhaust pipe 30, and the zeolite on the surface of the metal porous body 43 is introduced. and / or CO ₂ in the exhaust gas by the activated carbon is adsorbed, then fed natural gas, O ₂ and is reacted with CH ₄ with is converted to CO and H ₂ in the exhaust gas, and CO ₂ CH ₄ was reacted to reform the reformed fuel of CO and H ₂ O, and then steam vaporized by the heat energy of the exhaust gas was introduced into the compartment 55 through the steam pipe 45 to delay the reaction C.
H ₄ is reformed by steam, that is, H ₂ O to form CO and H ₂
To reform the fuel, and thereby all natural gas reacts with the reformed fuel of CO and H ₂ to reform, and air is sent from the air introduction pipe 64 to the compartment 55 to reform. Fuel is supplied to the engine together with air through the intake pipe 33 and then the intake manifold 16.

[0043]

As described above, the gas engine having the fuel reforming device according to the present invention is installed in the main chamber in a state where the communication port that connects the main chamber and the sub chamber is blocked by the sub chamber control valve. Since the reformed fuel of natural gas and air are supplied and the natural gas is supplied to the sub chamber, it is possible to reliably ignite and burn the natural gas having a constant property in the sub chamber at a predetermined temperature.
The combustion flame ejected from the sub chamber is propagated by combustion to the mixture of reformed fuel and air existing in the main chamber 1, and the combustion period of the secondary combustion can be shortened to improve the thermal efficiency.
Further, the natural gas is effectively reformed into a reformed fuel of CO and H ₂ by the reforming fuel device by utilizing the thermal energy of the exhaust gas and CO ₂ in the exhaust gas to improve the thermal efficiency of the engine. Can be made.

[Brief description of drawings]

1 is a sectional view showing an embodiment of a gas engine having a natural gas reforming apparatus according to the present invention.

FIG. 2 is an enlarged cross-sectional view showing a sub chamber of the gas engine of FIG.

FIG. 3 is a schematic explanatory view showing a fuel supply system in this gas engine.

FIG. 4 is a diagram showing the valve timing of this gas engine.

5 is a cross-sectional view taken along the line BB of FIG. 6, showing an example of the fuel reformer provided in this gas engine.

6 is a cross-sectional view taken along the line AA of FIG. 5, showing the fuel reformer of FIG.

FIG. 7 is a cross-sectional view taken along line DD of FIG. 8, showing another example of the fuel reformer provided in this gas engine.

8 is a cross-sectional view of the fuel reformer of FIG. 5, taken along the line CC of FIG.

[Explanation of symbols]

1 main room 2 Sub-chamber 3 natural gas valves 4 cylinders 5 pistons 8 Sub-chamber control valve 11 cylinder block 12 cylinder head 13 Middle head 14 Combustion chamber members 15 Fuel reformer 16 intake manifold 17 Reforming fuel valve 18 glow plug 22 Natural gas passage 25 controller 27 Contact 30 exhaust pipe 33 Intake pipe 40 Reformed fuel passage 41 housing 42 rotating container 43 Metal porous body 45 steam pipe 46 Natural gas pipe 49 bulkhead plate 52 Entrance side opening 53 Exit side opening 55 compartments 56 bearing 57 base 58 vacuum layer 59 Seal member 60 reforming fuel pipe 61 space 62 gasket 63 Zirconia 64 air introduction pipe 65 air valve 66 Exhaust gas valve 67 Steam valve 68 Natural Gas Fuel Valve

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02B 19/10 101 F02B 19/10 101 23/02 23/02 N F02M 27/02 F02M 27/02 F K F-term (reference) 3G023 AA01 AB05 AB08 AC03 AC07 AD02 AD24 AE04 AE06 4G040 EA03 EA05 EA06 EA09 EB03 EB13 EB41 EB43

Claims (10)

[Claims] 1. A cylinder head attached to a cylinder block, a piston reciprocating in a cylinder formed on the cylinder block side, a main combustion chamber formed on the piston side, and a sub-combustion provided on the cylinder head. Chamber, a sub-chamber control valve disposed at a communication port that connects the main combustion chamber and the sub-combustion chamber, and heat energy of the exhaust gas discharged from the main combustion chamber and CO ₂
A fuel reforming device for reforming into ₂ and CO, a reforming fuel valve provided in a reforming fuel passage arranged in an intake pipe, and a natural gas supply passage for supplying natural gas to the auxiliary combustion chamber The sub-chamber control valve is opened in the latter half of the compression stroke to blow a lean mixture of air and reformed fuel from the main combustion chamber into the sub-combustion chamber. A gas engine comprising igniting and burning said natural gas. 2. The gas engine according to claim 1, wherein a glow plug is arranged above the auxiliary combustion chamber facing the auxiliary chamber control valve. 3. The natural gas valve has a volume ratio of 5 to 20%.
3. The gas according to claim 1 or 2, wherein the natural gas is supplied to the auxiliary combustion chamber by opening the auxiliary chamber control valve in a closed state from the latter half of the intake stroke to the first half of the compression stroke. engine. 4. The gas engine according to claim 1, wherein the reformed fuel valve is opened during an intake stroke to supply the reformed fuel to the main combustion chamber. 5. The sub chamber control valve according to claim 1, wherein the sub chamber control valve is set to open in the latter half of the compression stroke and close in the latter half of the exhaust stroke. Gas engine. 6. The sub-combustion chamber and a portion of the sub-chamber control valve which comes into contact with combustion gas are coated with ceramics such as corrosion resistant zirconia, according to any one of claims 1 to 5. The described gas engine. 7. The fuel reformer comprises a heat exchanger for recovering heat energy of the exhaust gas, CO in the exhaust gas.
The gas engine according to claim 1, further comprising: an adsorption device that adsorbs ₂ and a catalyst device that reforms the natural gas into the reformed fuel. 8. The fuel reformer comprises a fuel reforming control valve for sequentially supplying the exhaust gas, the natural gas and steam to the compartments of the rotary container. The gas engine according to any one of 1 to 7. 9. The fuel reformer comprises a tubular rotary container rotatably supported by a tubular housing, and the inside of which is divided into a plurality of compartments by a partition plate in a rotational direction. A porous metal body carrying an adsorbent, a catalyst and the like is housed in each of the compartments of the rotary container, and an exhaust pipe, a steam pipe and a natural gas pipe are connected to an inlet side opening and an outlet side opening of the housing, respectively. The gas engine according to claim 1, wherein the gas engine comprises: 10. The fuel reforming control valve for sequentially supplying the exhaust gas from the exhaust pipe, the steam from the steam pipe and the natural gas from the natural gas pipe to the rotary container in the fuel reformer. The gas engine according to claim 9, comprising: