JP2892235B2 - Cogeneration type gas engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cogeneration type gas engine having a gas engine using natural gas as a fuel and generating electric energy and hot water.

[0002]

2. Description of the Related Art Conventionally, a gas engine using natural gas, that is, natural gas as a main fuel, has been developed as a cogeneration type engine by a government research institute or a private company. This cogeneration engine
Power is taken out as electric energy by a generator, and the heat of the exhaust gas energy is heated by a heat exchanger to make hot water and used for hot water supply. This engine is expected to be used as an electricity supply system in a city. That is, when a gas engine is used for a cogeneration system, a general cooling engine has an engine cooling circuit using cooling water and a two-system cooling circuit for cooling exhaust gas. Each of the cooling circuit for cooling the exhaust gas and the engine cooling circuit has a steam / water separation tank or the like, and supplies hot water by a secondary heat exchanger using steam.

[0003] As engines using natural gas as fuel, there are, for example, those disclosed in JP-A-54-156911, JP-A-63-6358, and JP-A-1-232119.

The internal combustion engine disclosed in Japanese Patent Application Laid-Open No. 54-156911 compresses intake air and supplies it to a main combustion chamber, and supplies a part of the intake air to a jet cell ignition chamber.
The paraffinic hydrocarbon fuel is injected into the jet cell ignition chamber to form a rich mixture, the intake air and the mixture are further compressed, and the paraffinic hydrocarbon fuel is injected into the main combustion chamber, while Further compressing the intake air and the mixture to produce a lean mixture in the main combustion chamber and igniting the mixture in the jet cell ignition chamber before full compression of both mixtures is achieved to produce a hot gas stream; the flow of the heat had gas was charged to the mixture in the main combustion chamber to ignite the mixture of the main combustion chamber, thereby reducing the production of NO _X.

A gas engine driven heat pump system disclosed in Japanese Patent Application Laid-Open No. 63-6358 stores a flammable gas in a buffer tank, and the flammable gas is stored in a plurality of heat pumps from the buffer tank. The hot spring water after gas-liquid separation is heated to the required temperature by a heat pump, and the heated hot spring water is supplied to the heat load. And a control means for sequentially decreasing the number of heat pumps to be supplied with gas each time the detection pressure of the buffer tank by the pressure sensor decreases from the high pressure set pressure to the low pressure set pressure.

The engine for hydrogen and liquefied natural gas disclosed in Japanese Patent Application Laid-Open No. 1-223219 supplies either hydrogen as fuel or liquefied natural gas when the engine is in a low-load operation state. A control means for supplying liquefied natural gas as a fuel when the engine is in a high load operation state is provided.

[0007]

However, since the exhaust gas temperature of the heat shield type gas engine is considerably high and the exhaust gas energy, that is, the amount of heat, is large, steam is generated by heating water with the exhaust gas energy. It is easy. Moreover, it is possible to rotate the turbine using the steam.

However, in a gas engine using natural gas as a fuel, since the fuel is a gaseous substance, the fuel gas is drawn from the intake valve, compressed and ignited in the same manner as gasoline, so that the compression ratio must be increased. And the theoretical thermal efficiency (η = heat conversion of work / heat of fuel) is not always high. The commonly used gas engines are
The compression ratio is about 12 to 13, and the theoretical thermal efficiency is only 48%. When the power of the gas engine is electric energy, the thermal efficiency is 34 to 35%, and in some cases, it is less than 30%. Such efficiency. Therefore, the loss of cooling water and the energy of exhaust gas
70% of the hot water is released, and this heat energy is used to generate hot water by a heat exchanger. Even if it is used for hot water supply, the amount of hot water is so large that it cannot be sufficiently used by general facilities. Therefore, electric energy obtained from the gas engine is expensive. Moreover, such a gas engine has a compression ratio of 18
The theoretical thermal efficiency of a diesel engine described above is significantly different from 57%.

Therefore, at the present time, it is desired to improve the thermal efficiency when extracting the power of the gas engine as electric energy. Therefore, it has been considered to adopt a heat shield type gas engine as a gas engine to improve thermal efficiency. A gas engine uses natural gas as a fuel, and the fuel is a gas.
Therefore, when air and gaseous fuel is sucked into the cylinder during the suction stroke, and then compressed and highly compressed, the temperature increases,
The phenomenon of self-ignition occurs, and knocking occurs. However, if the compression ratio of the natural gas is not less than 12, the natural gas will self-ignite.

[0010] In particular, in a cogeneration type gas engine, reducing the level of exhaust gas is an important issue. EGR (exhaust gas recirculation) is said to be effective in reducing nitrogen oxides. However, in the heat shielding type gas engine, the exhaust gas discharged is high temperature,
Exhaust gas used as the lower the temperature, there is a phenomenon that occurs of the NO _X can be reduced. Further, in the heat shield type gas engine, since the wall surface temperature of the combustion chamber rises, the self-ignition problem that the fuel supplied to the combustion chamber self-ignites before the ignition timing increases. That is, in the heat shield type gas engine, since the wall temperature of the combustion chamber rises to about 600 ° C. or more, when natural gas, gasoline, or the like is used as a fuel, if the compression ratio is configured to be high, the fuel from the intake valve will When the gas and air are mixed and highly compressed, self-ignition occurs, and combustion starts shortly before the top dead center TDC, which causes knocking and does not work as an engine.

[0011] Accordingly, an object of the present invention is to solve the above problems, performs EGR using an exhaust gas discharged from the gas engine for reducing the NO _X,
This is to reduce the temperature of exhaust gas used for EGR. In particular, it is used for EGR in a state where the temperature of exhaust gas of a heat shield type gas engine is lowered, and the exhaust gas energy is recovered as electric energy by an energy recovery device. Then, water is heated in the first heat exchanger by the exhaust gas from the energy recovery device to generate steam, and the steam is used to rotate the steam turbine to recover as electric energy. It is an object of the present invention to provide a cogeneration type gas engine for performing EGR by sending exhaust gas whose temperature has been lowered by absorbing thermal energy to a compressor of a turbocharger.

[0012]

The present invention is configured as follows to achieve the above object. That is,
The present invention relates to a cogeneration type gas engine having a gas engine using natural gas as a fuel and a generator mounted on a rotating shaft of the gas engine to extract electric energy, and a turbocharger driven by exhaust gas energy of the gas engine. An energy recovery device including a turbine driven by exhaust gas energy exhausted from the turbocharger and a generator, a steam generator for generating steam using thermal energy of exhaust gas exhausted from the turbine, A steam turbine provided in the energy recovery device driven by steam discharged from the heat exchanger, a heat exchanger into which steam discharged from the steam turbine is fed, and exhaust gas discharging exhaust gas passing through the steam generation device. Passage and compressor of the turbocharger The exhaust gas recirculation passage having a control valve that communicates the air passage for supplying air to a cogeneration type gas engine, characterized in that it comprises a.

This cogeneration type gas engine has a sensor for detecting an engine load, and in response to a detection signal from the sensor, operates or controls the operation state of a plurality of cylinders to control the engine load per cylinder. And a controller for performing control for increasing the pressure as high as possible.

[0014]

The cogeneration type gas engine according to the present invention is configured as described above, and operates as follows. That is, the cogeneration gas engine includes a turbocharger driven by exhaust gas energy, an energy recovery device including a turbine and a generator driven by exhaust gas energy exhausted from the turbocharger, and an exhaust gas from the turbine. A steam generator that generates steam with the thermal energy of the exhaust gas to be discharged, and communicates an exhaust passage that discharges exhaust gas that has passed through the steam generator with an air passage that supplies air to a compressor of the turbocharger. The exhaust gas supplied to the compressor through the exhaust gas recirculation passage has a low temperature because of having the exhaust gas recirculation passage provided with the adjusting valve.

Therefore, in this cogeneration type gas engine, low temperature exhaust gas can be used for EGR,
The effect of GR increases. That is, CO, C in exhaust gas
When O ₂ increases the amount of gas in the air and CO and CO ₂ are appropriately dispersed in the air and the temperature is low, there is an effect that NO _X is reduced. Further, the low temperature of the exhaust gas be mixed fresh air, without increasing the intake air, since no high too compression end temperature, to reduce the generation of the NO _X and can control the combustion temperature low This has the effect. Furthermore, if the temperature of the exhaust gas used for EGR is low,
A predetermined amount of fresh air can be supplied to the engine without expanding the fresh air. In addition, since the compressor of a turbocharger is usually made of an aluminum alloy, passing high-temperature exhaust gas through the compressor causes problems such as corrosion.However, this cogeneration gas engine uses low-temperature exhaust gas. Since it is used for EGR, problems such as corrosion do not occur.

For example, in the case of a gas engine, when the combustion chamber is constructed as a heat shielding structure and is configured as a heat shielding type gas engine, the temperature of the exhaust gas becomes about 900 ° C., and the exhaust gas becomes a turbine of a turbocharger. , The temperature of the exhaust gas is reduced to about 700 ° C. Next, the exhaust gas discharged from the turbine drives the turbine of the energy recovery device, and the temperature of the exhaust gas is 600 ° C to 50 ° C.
Lowers to 0 ° C. Next, the exhaust gas discharged from the turbine of the energy recovery device is passed through a steam generator, and the temperature of the exhaust gas whose thermal energy has been absorbed by the steam generator is 3.
The temperature drops to about 00 ° C. The steam generated by the steam generator is sent to a heat exchanger for hot water supply, and the steam temperature becomes 2
It falls to 00 ° C to 100 ° C. Therefore, the exhaust gas used for EGR is about 300 ° C., and the temperature of the exhaust gas is set to 100 ° C. to 200 ° C. depending on the structure of the steam generator.
And the generation of NO _X can be reduced.

This cogeneration type gas engine drives a turbocharger by exhaust gas energy of a heat shield type gas engine, and has an energy recovery device having a generator with exhaust gas energy exhausted from a turbine of the turbocharger. The exhaust gas exhausted from the turbine of the energy recovery device converts water into heat by exchanging water with a steam generation device, and the steam drives a steam turbine provided in the energy recovery device. Since high-temperature steam discharged from the steam turbine is heat-exchanged by a heat exchanger to heat water for hot water supply, exhaust gas energy can be converted into steam and recovered as electric energy and hot water supply, thereby providing a highly efficient system. can do.

That is, if the thermal efficiency of the heat shield type gas engine is about 40%, about 15% of heat energy is recovered as electric energy by the turbocharger and the energy recovery apparatus, and about 5% is recovered by the steam turbine. % Of thermal energy is recovered as electrical energy, providing a highly efficient engine with a total thermal efficiency of about 60%.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cogeneration type gas engine according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic explanatory view showing one embodiment of a cogeneration type gas engine according to the present invention, FIG. 2 is a schematic sectional view showing one embodiment of a turbocharger incorporated in the cogeneration type gas engine, and FIG. FIG. 4 is a schematic sectional view showing an embodiment of an energy recovery device incorporated in a cogeneration type gas engine. FIG. 4 is a schematic sectional view showing an embodiment of a heat shield type gas engine incorporated in the cogeneration type gas engine. 5 is a cross-sectional view taken along line AA of FIG.

This cogeneration type gas engine has a gas engine using natural gas, that is, natural gas as a fuel, and a generator 60 attached to a rotating shaft 61 of the gas engine to take out electric energy. It can supply hot water. Further, in this embodiment, a heat shield type gas engine 50 is used as the gas engine.

The cogeneration type gas engine includes a turbocharger 51 driven by exhaust gas energy of a heat shield type gas engine 50, a turbine 59 driven by exhaust gas energy exhausted from a turbine 56 of the turbocharger 51, and a power generator. Recovery device 52 provided with a heat generator 57, a steam generator 54 which is a heat exchanger that generates high-temperature steam by thermal energy of exhaust gas exhausted from a turbine 59 of the energy recovery device 52, and steam from the steam generator 54 A steam turbine 58 provided in an energy recovery device 52 driven by the steam turbine, and a hot water supply heat exchanger 53 for generating hot water with high-temperature steam discharged from the steam turbine 58.

In this cogeneration type gas engine, water is heated by the heat exchanger 53 using steam discharged from the steam turbine 58 to make hot water, and the hot water can be used for hot water supply. The turbocharger 51 may use a TC consisting of a turbine and a compressor, or, as shown in FIG. 2, a turbine 56 driven by exhaust gas from a heat shielding type gas engine 50,
Including a compressor 71 connected to a shaft 73 and a generator / motor 72 provided on the shaft 73
Can also be used. In addition, the energy recovery device 5
3, a turbine 59 driven by exhaust gas energy from the turbocharger 51 and a steam turbine 58 driven by steam from the steam generator 54 are connected by a shaft 74 as shown in FIG. Is provided with a generator 57 provided in the energy recovery device 52.

In this cogeneration type gas engine, exhaust gas generated by the heat shield type gas engine 50 is sent to the turbine 56 of the turbocharger 51 through the exhaust passage 70, and the exhaust gas energy of the exhaust gas is The electric energy is collected by the electric motor 72 and stored in the electric power combining means 33, and the compressor 71 is driven. By driving the compressor 71, the intake air is supercharged to the heat shield type gas engine 50 through the intake passage 69. The exhaust gas exhausted from the turbine 56 is sent to the turbine 59 of the energy recovery device 52 through the exhaust passage 65, and the exhaust gas energy of the exhaust gas is recovered as electric energy by the power generator 57 and stored in the electric power combining means 33. . Further, since the exhaust gas exhausted from the turbine 59 of the energy recovery device 52 is not high-speed but has a considerably high temperature and thermal energy, the exhaust gas passes through the exhaust passage 66 to the steam generator 54. And heat the water with the exhaust gas to generate steam. Exhaust gas generated by heating water is deprived of thermal energy, has a low temperature, and has little velocity energy, and is discharged through the exhaust passage 67.

[0024] In particular, the cogeneration type gas engine is to reduce the occurrence of the NO _X using a low temperature exhaust gas EGR, the exhaust passage 67 for discharging exhaust gas passing through the steam generator 54 Air passage 37 for supplying air to compressor 71 of turbocharger 51
And an exhaust gas recirculation passage 36 that communicates with the exhaust gas. In addition, an adjustment valve 35 is provided at a connection between the exhaust gas recirculation passage 36 and the air passage 37 to adjust the flow rate of the exhaust gas of the EGR. As described above, by providing the exhaust gas recirculation passage 36, the exhaust gas transfers heat energy to the turbocharger 51 and the energy
The exhaust gas which has been sufficiently absorbed by the steam generator 2 and the steam generator 54 and whose temperature has decreased can be used for EGR. If lowering the temperature of the exhaust gas, even with exhaust gas to EGR, it is possible to reduce the generation of nitrogen oxides NO _X,
Extremely effective. As shown in FIG. 4, in a gas engine having a communication hole valve 4 that shuts off communication between the main chamber 1 and the sub-chamber 2, NO _X is mainly generated in the main chamber 1, but exhaust gas is exhausted to the main chamber 1. By sending the gas as EGR, the generation of NO _X generated in the main chamber 1 can be suppressed.

For example, when a heat shield type gas engine is used, the temperature of the exhaust gas is about 900 ° C., and the exhaust gas drives the turbine 56 of the turbocharger 51 to raise the temperature of the exhaust gas to about 700 ° C. To decline. Next, the exhaust gas discharged from the turbine 56 is supplied to the energy recovery device 52.
, And the temperature of the exhaust gas is 600
To 500 ° C. Next, the exhaust gas discharged from the turbine 59 of the energy recovery device 52 is passed through the steam generator 54, and the temperature of the exhaust gas having absorbed the thermal energy by the steam generator 54 is reduced to about 300 ° C.
Therefore, the exhaust gas used for EGR is about 300 ° C., and the temperature of the exhaust gas can be reduced to 100 ° C. to 200 ° C. depending on the configuration of the steam generator 54, thereby reducing the generation of NO _{X in} the gas engine. can do. Further, the steam generated by the steam generator 54 is sent to the hot water supply heat exchanger 53, the steam temperature drops to 200 ° C. to 100 ° C., the steam is released, and the heat energy is radiated to the atmosphere.

Further, in this cogeneration type gas engine, when performing EGR, the concentration of CO _{2 in} the exhaust gas of the EGR always becomes a problem. Accordingly, a sensor for detecting an engine load in a gas engine, and control for stopping or operating the operation states of a plurality of cylinders in response to a detection signal from the sensor to increase the engine load per cylinder as much as possible. Is provided. For example, when the gas engine is partially loaded, the cylinders determined in advance by the controller are deactivated and the cylinders are operated with reduced cylinders, thereby increasing the load per cylinder and increasing the engine load. It is preferable as an exhaust gas.

Further, the steam generated by the steam generator 54 is sent to a steam turbine 58 of the energy recovery device 52 through a steam passage 62. The steam blown from the nozzle 75 of the steam turbine 58 rotates the blade 76 to generate a rotating force of the shaft 74 and is collected by the generator 57 as electric energy. Since the steam discharged from the steam turbine 58 is still hot, it is sent to the heat exchanger 53 through the steam passage 63. In the heat exchanger 53, the steam heats the water to make hot water, and the hot water becomes clean hot water, and is used for hot water supply through the hot water passage 68. The steam is deprived of heat energy by the heat exchanger 53 and is released as water. In some cases, the water can be sent again to the steam generator 54 by a water pump or the like and circulated.

This cogeneration type gas engine uses a heat shield type gas engine 50. The exhaust gas temperature is considerably high and the amount of heat is large, so that it is easy to generate steam with the exhaust gas. is there. The steam turbine 58 can be rotated by using the steam, and the hot water can be supplied by the heat exchanger 53 by using the heat energy of the remaining exhaust gas after the steam turbine 58 is rotated. It is. Since the heat shield type gas engine 50 is not provided with a cooling system, if the heat efficiency of the heat shield type gas engine 50 is burned at, for example, 40% or more, the remaining 60% of the heat amount becomes exhaust gas energy and the amount of heat is reduced. Moving. 15% of the exhaust gas energy is converted into power by the turbocharger 51 and the energy recovery device 52. The remaining thermal energy is
Is used to convert the water supplied to the steam generator 54 through the passage 64 into steam by the steam generator 54 to generate a large amount of steam. The steam drives a steam turbine 58 provided in the energy recovery device 52, and the generator 57 recovers 5% of power as electric energy. Then, the high-temperature steam in the heat exchanger 53 is used to heat the energy from the water supply source 34 such as tap water to generate hot water used for hot water supply through the passage 68. As described above, in this cogeneration type gas engine, 60% thermal efficiency is obtained because electric energy is generated, and an engine with extremely high efficiency as electric energy can be provided.

Next, an embodiment of the heat shield type gas engine 50 will be described with reference to FIGS. The heat shield type gas engine includes a cylinder block 14 and a cylinder block 14.
, An intake port 25 formed in the cylinder head 7, an intake valve 20 arranged in the intake port 25, an exhaust port 31 formed in the cylinder head 7, and an exhaust valve arranged in the exhaust port 31 32, a sub-chamber 2 formed by a wall 3 of a heat shielding structure arranged in a hole 19 formed in the cylinder head 7, a cylinder liner 22 fitted in a hole 21 formed in the cylinder block 14, and a cylinder liner 22. It has a piston 15 reciprocating in the formed cylinder 18, a main chamber 1 of a heat shielding structure formed on the cylinder 18 side, and a communication hole 30 formed in a wall 3 communicating the main chamber 1 and the sub-chamber 2. doing.

In the heat shield type gas engine 50, the main room 1
Is formed by a head liner 10 which is a wall fitted into a hole 9 formed in the cylinder head 7. The headliner 10 has a liner upper part 28 which forms a part of the cylinder 18.
And a head lower surface 11. On the upper surface of the head lower surface 11, a wall 3 constituting the sub chamber 2 is integrally formed. The wall 3 has a hole 19 in the cylinder head 7.
An upper wall body 12 and a lower wall body 13 fitted to each other. A valve seat 26 for the intake / exhaust valves 20 and 32 and a valve seat 24 for the communication hole valve 4 are formed on the lower surface 11 of the head.

In the heat shield type gas engine 50, a fuel tank 27 containing natural gas as fuel, a pressure accumulating chamber 6 for accumulating natural gas from the fuel tank 27,
In order to supply the natural gas in the accumulator 6 from the fuel inlet 23 to the sub-chamber 2, the gas is disposed in the fuel passage 8 communicating the sub-chamber 2 and the accumulator 6, and the communication hole 30 communicating the main chamber 1 and the sub-chamber 2. A communication hole valve 4 is provided at the fuel inlet 23 and has a fuel valve 5 which is opened in the suction stroke and supplies natural gas to the sub-chamber 2. Since the temperature of the communication hole 30 becomes high due to the combustion gas, the communication hole valve 4 disposed in the communication hole 30 is made of ceramics such as silicon nitride and silicon carbide having high temperature strength and excellent heat resistance. The fuel valve 5 has an electromagnetic valve driving device that is opened and closed by an electromagnetic force, and a valve opening period is determined according to an engine load. When the fuel valve 5 opens the fuel inlet 23, a necessary amount of natural gas, ie, gas fuel, is supplied from the accumulator 6 to the sub-chamber 2.

The piston 15 has a piston head 16 made of ceramics such as silicon nitride having excellent heat resistance.
And a piston skirt 17 fixed to the piston head 16 by a metal ring with a coupling ring 29. The headliner 10, the upper wall 12 and the lower wall 13 constituting the wall 3, the cylinder liner 22, and the piston head 16 are made of ceramics such as silicon nitride having excellent heat resistance. Therefore, even if the gas temperature in the latter stage of combustion increases, the gas has sufficient strength, the emission of unburned hydrocarbons HC and the like is reduced, and a highly efficient engine can be achieved.

The heat shield type gas engine 50 is operated by sequentially repeating four strokes of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. First, in the intake stroke, the intake valve 20 is connected to the intake port. Open 25 and main room 1
Air is supplied to the communication hole 30 and the communication hole 30
The fuel valve 5 is opened with the valve closed, and natural gas fuel is supplied from the accumulator 6 to the sub-chamber 2 through the fuel passage 8. At this time, since the exhaust gas after combustion remains in the sub chamber 2, when the gas fuel from the pressure accumulating chamber 6 is introduced,
The gas fuel receives heat and is activated in the sub-chamber 2.

Next, in the compression stroke, the communication hole 30 is closed by the communication hole valve 4, and the compression ratio of the intake air in the main chamber 1 is increased. Next, at the end of the compression stroke, the communication hole valve 4 opens the communication hole 30, and high-compression and high-temperature air flows from the main chamber 1 into the sub-chamber 2 through the communication hole 30, and the intake air is activated gas fuel. To promote ignition and combustion, the combustion progresses rapidly, and the flame of the sub-chamber 2 blows out to the main chamber 1, moves to the expansion stroke, and promotes mixing with fresh air existing in the main chamber 1. Complete combustion in a short time. In this expansion stroke, the communication hole 30 is kept open and a flame is blown from the sub chamber 2 to the main chamber 1 to perform work, and the communication hole 30 is closed at the end of the exhaust stroke.

The heat shield type gas engine 50 is provided with a communication hole 30 and a fuel inlet 23 in the sub-chamber 2, and accumulates natural gas from the fuel tank 27 storing natural gas in the accumulator 6. Natural gas is supplied from the fuel inlet 23 into the sub-chamber 2 while the communication hole 30 is closed by the communication hole valve 4, and the intake air sucked into the main chamber 1 from the intake port 25 into the main chamber 1 is communicated by the communication hole valve 4. Is closed and the intake air is not supplied to the sub-chamber 2 in the compression stroke of the ascent of the piston 15 in a state where the intake air is not supplied. The supplied fuel does not self-ignite and knocking does not occur. When the communication hole valve 4 opens the communication hole 30, the intake air with a high compression ratio flows from the main chamber 1 into the sub-chamber 2, where the fuel gas and the intake air are mixed and ignited. generation of the NO _X is suppressed at high burn in a rich state. Further, gas fuel from the accumulator 6 is introduced into the sub-chamber 2 containing the exhaust gas after combustion, and the gas fuel receives heat and is activated. Also,
Even if the intake air has a high compression ratio in the main chamber 1, the sub-chamber 2 is closed by the communication hole valve 4, so that the activated gas fuel in the sub-chamber 2 does not self-ignite and knocking occurs. Nothing.

Further, when the communication hole 30 is opened, high-compression and high-temperature air flows from the main chamber 1 into the sub-chamber 2, and the mixing of the gas fuel and the intake air is promoted at a stretch to ignite.
NO _X and fast burn in large fuel-rich equivalence ratio
Is suppressed. Then, the pressure in the sub-chamber 2 rises at once, and the combustion is promoted. At the same time, the flame blows out from the sub-chamber 2 to the main chamber 1 through the communication hole 30 at a stretch, and the flame is mixed with fresh air in the main chamber 1 Promotes the combustion speed to complete the ideal secondary combustion. Accordingly, the thermal barrier engine, NO _X, the generation of HC and the like can be greatly reduced. The fuel valve 5 is driven by an electromagnetic force, and the fuel valve 5 can be set so as to determine the valve opening period by a controller in response to a detection signal of a load sensor that detects an operation state of an engine load.

[0037]

The cogeneration gas engine according to the present invention is configured as described above and has the following effects. That is, the cogeneration gas engine includes a turbocharger driven by exhaust gas energy, an energy recovery device including a turbine and a generator driven by exhaust gas energy exhausted from the turbocharger, and an exhaust gas from the turbine. A steam generator that generates steam with the thermal energy of the exhaust gas to be discharged, and communicates an exhaust passage that discharges exhaust gas that has passed through the steam generator with an air passage that supplies air to a compressor of the turbocharger. The exhaust gas recirculation passage provided with an adjusting valve that adjusts the adjusting valve to supply the exhaust gas of EGR to the compressor through the exhaust gas recirculating passage. Exhaust gas that has passed through is absorbed by thermal energy and has a low temperature. Therefore, can be used to recirculate the gas engine low temperature exhaust gas as EGR, it is possible to reduce the generation of NO _X.

For example, in the case of a heat shield type gas engine, the temperature of the exhaust gas is about 900 ° C., but the exhaust gas energy drives the turbine of the turbocharger and the turbine of the energy recovery device. And
Further, by absorbing the heat energy through the steam generator, the temperature of the exhaust gas can be reduced to about 300 ° C, and in some cases, the temperature of the exhaust gas can be reduced to 100 ° C to 200 ° C. becomes highly preferred temperature, it is possible to reduce the generation of NO _X.

Further, the turbocharger is driven by the exhaust gas energy of the heat shield type gas engine, and the energy recovery device provided with the generator is driven by the exhaust gas energy exhausted from the turbine of the turbocharger. A steam generator that generates steam by the thermal energy of exhaust gas exhausted from the turbine of the turbine, and drives the steam turbine of the energy recovery device by the steam released from the steam generator, whereby the exhaust gas Can be converted into electric energy, so that a system with high thermal efficiency can be provided. Furthermore, extremely high energy recovery can be achieved by heating the high-temperature steam discharged from the steam turbine with a hot water supply heat exchanger to generate hot water.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing one embodiment of a cogeneration type gas engine according to the present invention.

FIG. 2 is a schematic sectional view showing one embodiment of a turbocharger incorporated in the cogeneration type gas engine.

FIG. 3 is a schematic sectional view showing one embodiment of an energy recovery device incorporated in the cogeneration type gas engine.

FIG. 4 is a schematic sectional view showing an embodiment of a heat shield type gas engine incorporated in the cogeneration type gas engine.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

[Explanation of symbols]

 35 adjustment valve 36 exhaust gas recirculation passage 37 air passage 50 heat-shielded gas engine (gas engine) 51 turbocharger 52 energy recovery device 53 heat exchanger 54 steam generator 56, 59 turbine 57 generator 58 steam turbine 60 generator 61 Rotary shaft 67 Exhaust passage 71 Compressor

Claims (2)

(57) [Claims] 1. A co-generation type gas engine having a gas engine using natural gas as a fuel and a generator mounted on a rotating shaft of the gas engine to extract electric energy, wherein a turbo driven by exhaust gas energy of the gas engine is provided. An energy recovery device including a charger, a turbine driven by energy of exhaust gas exhausted from the turbocharger, and a generator, a steam generator for generating steam by thermal energy of exhaust gas exhausted from the turbine, and the steam generation A steam turbine provided in the energy recovery device driven by steam discharged from the device, a heat exchanger into which steam discharged from the steam turbine is fed, and an exhaust passage discharging exhaust gas passing through the steam generation device And the compressor of the turbocharger A cogeneration type gas engine having an exhaust gas recirculation passage having an adjustment valve communicating with an air passage for supplying air to the air. 2. A sensor for detecting an engine load, and a control for stopping or operating the operation states of a plurality of cylinders in response to a detection signal from the sensor to increase an engine load per cylinder as much as possible. The cogeneration type gas engine according to claim 1, further comprising: a controller that performs the following.