JP6653911B1 - Mixer and gas supply system for gas engine for power generation - Google Patents

Abstract

[Object] To provide an optimum mixer for supplying gas fuel to a power generation gas engine operable with city gas and LPG. A venturi V contraction section 12 of an inlet pipe section 11 is formed. Outside the contraction section 12, an upper body 1 having an upper space 14 is provided. A lower space 24 is provided outside the portion 22, and an annular space N including the lower space 24 and the upper space 14 is formed. The annular space N has a first inlet portion 251 and a first fuel jet A main body 2 provided with a second inlet portion 261 and a second fuel jet 4B for 4A and LPG fuel; and a throttle body 3 provided with a throttle 32 continuously to the main body 2. An annular slit S as a gap is formed at the narrowest portion of the venturi V between the contraction portion 12 and the peripheral edge of the end portion of the diffusion portion 22, and the first fuel jet 4A and the second fuel jet The exit side of 4B is connected to the main body 2. [Selection diagram] Fig. 1

Description

The present invention separates any one type of gas from a different gas supply source into a power generation gas engine operable with different gas charges such as city gas and LPG (liquefied petroleum gas (propane C ₃ H ₈ etc.)). A mixer for supplying gaseous fuel to a power generation gas engine, wherein the mixer and gas supply system for a power generation gas engine are capable of precisely controlling fuel supply and mixing fuel and air in a homogeneous manner. About.

  A gas engine generator with a displacement of 5,000 cc or less can be used for emergency power supply in the event of a disaster, for power supply on remote islands, and for peak power cuts when the demand for power is near the limit of the power company's supply capacity. . Generally, city gas and LPG (liquefied petroleum gas) are used as fuels for gas engines. City gas is extremely easy to handle, and LPG is easy to transport and highly safe if filled into cylinders. In addition, deterioration and deterioration (sourcing) do not occur over time unlike gasoline and light oil.

  Patent Document 1 (Japanese Patent Application Laid-Open No. 52-113408) discloses an LPG engine. A large number of such gas engines now exist. Further, an engine using fuel that can use city gas together with LPG is expected to be an engine for power generation that is particularly resistant to disasters that regularly use city gas.

  In such a gas engine for power generation that can use both gas fuel of city gas and LPG, only one of the city gas supply source and the LPG supply source is partitioned and selected, and the gas engine for power generation is selected. Must be supplied through a mixer. This gas engine for power generation, which can use both city gas and LPG gas fuel, normally uses city gas. When a disaster such as an earthquake occurs and the supply of city gas is stopped, LPG is supplied to the gas engine for power generation instead of gas.

JP-A-52-113408

  By the way, in a power generation gas engine that can use either the city gas fuel or the LPG fuel, either one of the city gas supply source or the LPG supply source is supplied to the power generation gas engine via a switching valve. Is required. The mixer is a unique functional component in the gas engine for power generation, and is the most important device. The mixer has a function of precisely controlling the flow rate of the fuel supplied to the gas engine for power generation and a function of uniformly mixing the fuel with the air.

  In addition, the mixer included in the power generating gas engine capable of using both the city gas fuel and the LPG fuel must be able to accept two different types of gas fuels, that is, the city gas fuel or the LPG fuel. . However, city gas and LPG are different in various properties such as density and mass, and cannot be used with an ordinary mixer that can use only one kind of gas fuel. In other words, the mixer must use gas fuels having different properties for city gas and LPG in accordance with the respective properties.

  A mixer 3 is used in the LPG engine of Patent Document 1 (Japanese Patent Application Laid-Open No. 52-113408). In this mixer, fuel is ejected from the nozzle 27 of the venturi section. A gas adjusting screw 26 is provided in the passage for guiding the gas fuel, and the passage area is determined by the position of the tapered valve body at the tip. Variations in this position directly affect the control characteristics of the air-fuel ratio.

  In particular, when purifying exhaust gas with a three-way catalyst, the fuel flow rate should be controlled so that the stoichiometric air-fuel ratio (the air-fuel ratio after combustion of the fuel in the cylinder, theoretically, no oxygen or fuel molecules remain). Must-have. In the structure of the mixer (FIG. 3), the fuel passage area is determined by the position of the valve element, so that the required performance cannot be always realized.

  In addition, it is not sufficient to eject fuel from the nozzles 27 (two in the figure) to homogeneously mix the air and the fuel, and it is not possible to avoid uneven distribution of the fuel. The main purpose of the vaporizer 7 (structure shown in FIG. 2) upstream of the mixer 3 is to vaporize the fuel that has flowed in as a liquid.

  It has a function of regulating the pressure of fuel at the inlet of the mixer 3 for controlling the amount of air and the amount of fuel to be taken in by the gas engine for power generation to the same pressure as the pressure immediately before the mixer 3 (after the air cleaner). Not. The above is a problem that occurs when using the LPG fuel in the mixer, but substantially the same problem occurs when using the city gas fuel.

  In particular, an object of the present invention is to provide a mixer suitable for a gas engine for power generation that can cope with the use of both gas fuels of city gas and LPG (liquefied petroleum gas). Then, the air-fuel mixture having the stoichiometric air-fuel ratio is always supplied to the gas engine for power generation that operates at a steady rotation speed while having a simple configuration so that the exhaust gas can be purified by the three-way catalyst. Therefore, the necessary conditions of the mixer are as follows. First, precise control of fuel supply is performed regardless of whether the fuel is city gas or LPG (liquefied petroleum gas). It is an object of the present invention to provide a mixer as an inexpensive and simple structure that the fuel and the air can be homogeneously mixed with any gas fuel of (petroleum gas).

The inventor of the present invention has conducted intensive studies to solve the above-mentioned problems. As a result, the inventors of the present invention have found that the invention of claim 1 has a venturi contraction portion formed below the external air introduction pipe portion, An upper body provided with an inverted U-shaped annular upper space, and a U-shaped annular lower space provided outside the diffusion portion of the venturi connected to the contraction portion. A main body having a first inlet for city gas fuel, a second inlet for the first fuel jet and a second fuel jet for LPG fuel, and a second fuel jet in the lower space from the outer peripheral side; the lower space and the upper space; An annular space having an O-shaped cross section, and a throttle body provided with a throttle continuously to the main body, between the peripheral edge of the contraction portion and the end portion of the diffusion portion, An annular slit is formed at the narrowest part as a gap In addition, the above problem is solved by providing a mixer for a power generating gas engine that is connected to the main body on the outlet side of the first fuel jet and the second fuel jet.

  According to a second aspect of the present invention, in the mixer structure of the gas generator for power generation according to the first aspect, the above problem is solved by providing a mixer of the gas engine for power generation in which the gap of the annular slit as the gap is a constant interval. . According to a third aspect of the present invention, in the mixer structure for a power generating gas engine according to the first aspect, the above problem is solved by providing a mixer for a power generating gas engine in which a gap of an annular slit as the gap has a variable interval. .

  According to a fourth aspect of the present invention, in the mixer structure of the gas generator for power generation according to the first or third aspect, a spacer having an appropriate thickness is interposed in a gap of the annular slit as the gap, and an inner diameter of the spacer is provided. The above-mentioned object is achieved by providing a mixer of a gas engine for power generation, wherein the portion is formed to have the same diameter as the outer shape of the annular space and the outer portion is formed to have the same outer shape as the lower end portion of the upper body. Settled.

According to a fifth aspect of the present invention, in the mixer structure of the gas engine for power generation according to the first, second, third or fourth aspect, the square of the diameter of the narrowest part of the venturi and the first fuel jet and the second fuel jet are used. The above problem has been solved by using a mixer for a gas engine for power generation in which the ratio of the square of the orifice diameter is kept constant. According to a sixth aspect of the present invention, in the mixer structure of the gas engine for power generation according to the first, second, third or fourth aspect, a first boss portion and a second boss portion are formed on an outer peripheral side of the main body. The first boss portion is provided with the first inlet portion and the first fuel jet, and the second boss portion is provided with the second inlet portion and the second fuel jet, and an outer periphery of the main body. The above-mentioned problem has been solved by providing a mixer for a power generation gas engine provided at a position on both sides in the radial direction of the venturi or on the periphery of the outer periphery.

The invention according to claim 7 is characterized in that a gas engine for power generation capable of using city gas and LPG, and a venturi contraction section formed below the external air introduction pipe section, and an inverted U An upper body provided with a U-shaped annular upper space, and a U-shaped annular lower space provided outside the diffusion portion of the Venturi that is continuous with the contraction portion ; From the side, a main body provided with a first inlet for city gas fuel, a first inlet for fuel gas and a second inlet for LPG fuel and a second fuel jet, and an O-shaped cross section comprising the lower space and the upper space -Shaped annular space, and a throttle body provided with a throttle continuously to the main body, between a narrow end portion of the venturi, between the contraction portion and an end periphery of the diffusion portion. An annular slit is formed as a gap In both cases, outlets of the first fuel jet and the second fuel jet are connected to the mixer connected to the main body, a city gas supply source, an LPG supply source, a valve chamber, and a valve chamber through which city gas flows in and out. A valve body provided with a first inflow path and a first outflow path, a second inflow path through which LPG flows in and out, and a second outflow path; and the first inflow path and the first outflow path housed in the valve body. A gas supply switching valve having a valve body that opens one of a flow path formed by the second flow path and a flow path formed by the second inflow path and the second outflow path and shuts off the other. A source and a first inlet of the mixer are communicated via the first inflow path and the first outflow path of the gas supply switching valve, and the LPG supply source and a second inlet of the mixer are connected to the gas inlet. The second inflow path of the supply switching valve and the first Detchi Metropolitan has solved the above problems by having a gas supply system of the power generation gas engine comprising communicates through.

  The invention according to claim 8 is the gas supply system for a gas engine for power generation according to claim 7, further comprising an ECU and a low-pressure adjusting valve, wherein the low-pressure adjusting valve is appropriately controlled by the low-pressure adjusting valve in accordance with a gas type according to a command from the ECU. The above problem has been solved by providing a gas supply system for a power generating gas engine that operates to a pressure. The invention according to claim 9 is the gas supply system for a gas engine for power generation according to claim 7 or 8, further comprising an ECU, wherein the gas supply switching valve is provided with a gas discriminating sensor and is connected to the ECU. The above object has been attained by providing a gas supply system for a power generating gas engine in which the type of gas passing through a supply switching valve is determined by the gas determination sensor and the ECU.

  In particular, the present invention is a gas engine for LPG (liquefied petroleum gas), CNG (compressed natural gas), or LNG (liquefied natural gas). It is a so-called gas engine that can be used with household propane gas (including butane) and city gas.

  According to the first aspect of the present invention, the mixer is configured such that the first boss portion and the second boss portion each have a main body provided with a fuel jet and a simple air-fuel mixture with a stoichiometric air-fuel ratio at a steady rotational speed. In addition to being able to provide a gas engine for power generation that operates on a fuel cell, it has the greatest advantage that fuel gas and air can be mixed homogeneously with an extremely simple configuration, and high efficiency fuel efficiency can be realized. .

  Further, a first boss provided with a first inlet for city gas fuel and a second boss provided with a second inlet for LPG fuel are separately provided on a main body of the mixer. I have. The size of the inner diameter of the gas fuel passage in each set of the first boss portion and the first inlet portion and the second boss portion and the second inlet portion can be appropriately set. The portion can be optimally sized as a passage for city gas fuel, and the second boss and the second inlet can be optimally sized as a passage for LPG (liquefied petroleum gas) fuel. Thus, the gas engine for power generation can use both the city gas fuel and the LPG (liquefied petroleum gas) fuel, regardless of whether the city gas fuel or the LPG (liquefied petroleum gas) fuel is used. Gas fuel can be appropriately supplied to the gas engine for power generation via the power supply.

  According to the second aspect of the present invention, since the gap of the annular slit as the gap is a constant interval, the city gas fuel or the LPG (liquefied petroleum gas) fuel is extremely stable and uniform with respect to the power generating gas engine. Can be supplied. According to the third aspect of the present invention, since the gap of the annular slit as the gap is variable, the ejection of gas fuel from the gap can be appropriately changed, and appropriate gas fuel supply can be performed depending on the size of the power generating gas engine. It can be carried out. According to the invention of claim 4, a spacer having an appropriately different thickness is interposed in the gap of the annular slit as the gap, and the inner diameter portion of the spacer is formed to have the same diameter as the outer shape of the annular space. Since the outer shape is formed to be the same as the outer cross-sectional shape of the lower end portion of the upper body, the variable gap structure can be made extremely simple, and the gap changing operation can also be simplified.

  According to the fifth aspect of the invention, the ratio of the square of the diameter of the narrowest part of the venturi to the square of the diameter of the orifice of the fuel jet is kept constant, so that the generation of city gas fuel and LPG (liquefied petroleum gas) fuel can be achieved. Supply to the gas engine can be optimized. In the invention of claim 6, a first boss portion and a second boss portion are formed on an outer peripheral side of the main body, and the first boss portion is provided with the first inlet portion and the first fuel jet, The second boss portion is provided with the second inlet portion and the second fuel jet, and is provided at a position on the outer periphery of the main body and on both sides in the radial direction of the venturi or on the outer periphery. Thus, the entrances of the city gas fuel and the LPG (liquefied petroleum gas) fuel are less likely to be erroneously recognized, and the gas fuel supply system of the gas engine for power generation can always easily make correct settings. Further, since the first boss portion and the second boss portion are provided on the outer circumference, the first boss portion and the second boss portion are set at an appropriate angle to each other without being on a straight line. Therefore, it can be installed according to the conditions used.

  According to the seventh aspect of the present invention, a city gas supply source and an LPG (liquefied petroleum gas) can be easily and quickly supplied from a city gas supply source and an LPG supply source via a mixer to a power generation gas engine capable of using both gas fuels. The gas flow can be partitioned. Gas engines for power generation usually use city gas, and when the supply of city gas is stopped in an emergency in the event of a disaster such as an earthquake, an LPG (liquefied petroleum gas) Can be used as a gas fuel for the power generation gas engine immediately after the occurrence of a disaster, and the power generation gas engine can be continuously operated. According to the eighth and ninth aspects, a circuit that can easily separate the city gas and the LPG in the power generation gas engine that can use both the city gas and the LPG (liquefied petroleum gas) can be formed with a very simple configuration. .

(A) is a longitudinal sectional view of the mixer according to the first embodiment of the present invention, (B) is a plan view of (A), (C) is a sectional view taken along the line X1-X1 of (A), and (D) is ( 3A is a sectional view taken along the line X2-X2 in FIG. FIG. 7 is a vertical sectional view of a mixer according to a second embodiment of the present invention, which is separated. (A) is a plan view of a spacer for a mixer of the second embodiment, (B) is a cross-sectional view of (A), and (C) is a part of a cross-sectional view of spacers having various thicknesses. FIG. 1A is an overall view of a gas supply system to a power generating gas engine using a mixer according to the present invention, and FIG. 1B is a system diagram of a main part of FIG. (A) is a system diagram in which a first gas supply channel is operating in a gas supply system using a mixer according to the present invention, and (B) is a second gas supply channel in a gas supply system using a mixer according to the present invention. FIG. 2 is a system diagram in which is operating. (A) is an enlarged sectional view of the first and second fuel jets for adjusting a fuel flow rate in the present invention, and (B) is a state diagram of a throttle portion. It is a state figure which expanded a part of low pressure regulation valve, shutoff valve, and gas supply switching valve. (A) is a vertical cross-sectional side view of the gas supply switching valve, (B) is a sectional view showing the state of the valve body when the first gas supply passage is in operation, and (C) is when the second gas supply passage is in operation. It is sectional drawing which shows the state of a valve body. (A) is a data table showing the characteristics of the mixer of the present invention when using city gas, and (B) is a data table showing the characteristics of the mixer of the present invention when using LPG (liquefied petroleum gas).

  Hereinafter, the mixer A according to the present invention will be described, and then the gas supply system centered on the mixer A will be described. The mixer A according to the present invention switches between two different types of gas fuel and supplies only one of them to a power generating gas engine 93 that can use two different types of gas as gas fuel.

  The different types of gas fuels are specifically city gas and LPG (liquefied petroleum gas). LPG (liquefied petroleum gas) is also referred to as LP gas. The power generating gas engine 93 used in the present invention is classified as a reciprocating internal combustion engine (engine). Therefore, the gas turbine engine 93 of the present invention does not include a gas turbine engine.

  First, the mixer A according to the present invention has three embodiments. In the first embodiment, as shown in FIG. 1, it is composed of an upper body 1, a main body 2, and a throttle body 3 as a basic structure. The basic structure in the first embodiment is common to the second and third embodiments. The three members of the upper body 1, the main body 2, and the throttle body 3 are connected and fixed by two or more through bolts 16. The reason why each body has a three-part structure is to facilitate its manufacture.

In the following, the mixer of the first embodiment will be described. In the upper body 1, a lower body 13 is formed at the lower end of an introduction pipe portion 11, and a Venturi V contraction portion 12 is formed inside the lower body 13. (See FIG. 1A). The lowermost peripheral edge of the contraction portion 12 is configured as the diameter D of the narrowest portion of the venturi V. Inwardly of and the lower body 13 at the outer side of the vena contracta 12 is inverted U-shaped circular ring-shaped upper space 14 is provided [see FIG. 1 (A)].

Next, the main body 2 is configured to form a pair with the upper body 1, and includes a lower tube 21 and a diffusion portion 22. The lower tube 21 is located at a lower end, and an upper side is located above the lower tube 21. The diffusion part 22 which gradually expands toward is formed. The diffusion part 22 is connected to the contraction part 12 of the upper body 1, and the lower pipe 21 is connected to the pipe 31 of the throttle body 3. The uppermost peripheral edge of the diffusion portion 22 is configured as the diameter D of the narrowest portion of the venturi V. That is, the Venturi V is formed by the contraction portion 12 of the upper body 1 and the diffusion portion 22 of the main body 2. Further, on the outside of the main body 2 of the diffuser portion 22, the lower space 24 of the U-shaped ring shape it is provided. That is, the upper space 14 of the upper body 1 and the lower space 24 of the main body 2 form an annular space N having an O-shaped cross section.

A first boss 25 having a first inlet 251 and a second boss 26 having a second inlet 261 are formed at the lower end of the main body 2. The first boss portion 25 plays a role of allowing the city gas fuel to flow into the mixer A via the first inlet portion 251. Further, the second boss portion 26 plays a role of flowing LPG (liquefied petroleum gas) into the mixer A via the second inlet portion 261.

  The first boss portion 25 and the second boss portion 26 are formed in a cylindrical shape that projects cylindrically along the diametrical direction of the diffusion portion 22 or the lower tube 21. More specifically, it is formed so as to protrude from both sides of the outer peripheral side surface of the main body 2 on an extended line along the diameter direction of the diffusion portion 22. That is, the first boss portion 25 and the second boss portion 26 are formed in a substantially linear direction along an arbitrary diameter line of the diffusion portion 22 or the lower tube 21 (see FIG. 1B).

  In addition, the first boss 25 and the second boss 26 may be formed at appropriate positions on the outer periphery of the main body 2 with the center of the diameter of the diffusion portion 22 or the lower tube 21 as a center [FIG. B) (see the second boss portion 26 by the two-dot chain line). In other words, the diffusion part 22 or the lower pipe 21 may be located at a position other than 180 degrees with respect to the center of the diameter of the diffusion part 22 or the lower pipe 21, and may be arranged on one straight line along the radial direction. It is not necessary.

  The first boss portion 25 is a hollow cylindrical tube as described above, and the inside thereof is formed as a cylindrical void portion 25a. Further, a first entrance 251 is formed in the first boss 25. The first inlet portion 251 is formed as a first inlet hole 251 h in the first boss portion 25, and allows gas fuel supplied from outside the mixer A to flow into the cylindrical gap portion 25 a of the first boss portion 25. It plays the role of flowing into

  The first inlet portion 251 specifically includes a hollow tubular sleeve 251a and a gap-like pipe 251b. The pipe 251b and the first inlet hole 251h are continuous. The pipe 251b communicates with the cylindrical gap 25a of the first boss 25 via the first inlet hole 251h, and communicates with a first fuel jet 4A described later [FIG. A) and (C)].

  The cylindrical gap 25a of the first boss 25 communicates with a lower space 24 described later. Further, in the cylindrical gap portion 25a of the first boss portion 25, an outer inner screw portion 25b on the outer side of the main body 2 and an inner inner screw 25c on the inner side are formed, respectively. A blind plug 27 having an external screw portion 27a screwed to the external inner screw portion 25b is fixedly fastened to the outer inner screw portion 25b, and closes the outer end side of the cylindrical gap portion 25a of the first boss portion 25.

  Further, a first fuel jet 4A having an external screw portion 41a screwed with the inner screw 25c of the cylindrical gap portion 25a of the first boss portion 25 is screwed and fixed. The pipe 251b of the first inlet 251 and the cylindrical gap 25a of the first boss 25 constitute a gas fuel flow path. The first inlet 251 and the first boss 25 define This constitutes the entrance of the city gas fuel in the mixer A.

  Further, the second boss portion 26 is a hollow cylindrical tube like the first boss portion 25, and the inside thereof is formed as a cylindrical void portion 26a. Further, the second boss portion 26 has a second inlet portion 261 formed therein. The second inlet portion 261 is formed as a second inlet hole 261 h in the second boss portion 26, and allows gas fuel supplied from the outside of the mixer A to flow into the cylindrical gap portion 26 a of the second boss portion 26. It plays the role of flowing into

  The second inlet 261 has substantially the same configuration as the first inlet 251, and specifically includes a hollow tubular sleeve 261 a and a hollow pipe 261 b. The pipe 261b is continuous with the second inlet hole 261h, and the pipe 261b communicates with the cylindrical gap 26a of the second boss 26 via the second inlet hole 261h. And communicates with a second fuel jet 4B to be described later (see FIGS. 1A and 1D).

  The cylindrical gap 26a of the second boss 26 communicates with a lower space 24 described later. Further, an outer inner screw portion 26b on the outer side of the main body 2 and an inner inner screw 26c on the inner side are formed in the cylindrical gap portion 26a of the second boss portion 26, respectively. A blind plug 27 having an external screw portion 27a screwed to the external inner screw portion 26b is fixedly fastened to the outer inner screw portion 26b, thereby closing the outer end side of the cylindrical void portion 26a of the second boss portion 26.

  Further, a second fuel jet 4B having an external screw portion 41a screwed with the inner screw 26c of the cylindrical gap portion 26a of the second boss portion 26 is screwed and fixed. The pipe 261b of the second inlet portion 261 and the cylindrical gap portion 26a of the second boss portion 26 constitute a gas fuel flow path. The second inlet portion 261 and the second boss portion 26 It constitutes the entrance of LPG (liquefied petroleum gas) in mixer A.

  The inner diameter of the cylindrical gap 25a of the first boss 25, the inner diameter of the pipe 251b of the first inlet 251 and the inner diameter of each of the first inlet holes 251h are determined by the inner diameter of the cylindrical gap 26a of the second boss 26, The pipes 261b of the second inlet 261 and the inner diameters of the second inlet 261 and the first inlet 251h are formed to be larger than the respective inner diameters. That is, LPG (liquefied petroleum gas) flows into the mixer A at one time through the first inlet 251 and the first boss 25, and the LPG (liquefied petroleum gas) flows into the mixer A at the second inlet 261 and the second boss 26. Is set to be larger than the amount flowing at once through the

  The first boss 25 is provided with a first fuel jet 4A for controlling the flow rate of the city gas fuel. A second fuel jet 4B for controlling the flow rate of LPG (liquefied petroleum gas) fuel is mounted on the second boss portion 26. The structure of the first fuel jet 4A and the second fuel jet 4B will be described. The structure of the first fuel jet 4A and the structure of the second fuel jet 4B are the same, and the signs of the respective parts are common. Each of the first fuel jet 4A and the second fuel jet 4B is provided with an external thread portion 41a on the outer periphery of the jet main body 41.

  A large diameter portion 42 is formed from the inlet side, and an orifice 43 having a small hole diameter d is formed to have a length w and communicate with the outlet side. The outlet side of the orifice 43 communicates with the lower space 24 of the main body 2. Here, the inlet side and the outlet side of the first fuel jet 4A and the second fuel jet 4B respectively correspond to the first fuel jet 4A in the first boss portion 25 and the second fuel jet 4B in the second boss portion 26. The entrance side is a position outside each of the first boss portion 25 and the first boss portion 25, and the exit side is a position facing inward of the main body 2. .

  Further, as described above, the blind plug 27 closes the outer distal end of the cylindrical gap 25a of the first boss 25 and the outer distal end of the cylindrical gap 26a of the second boss 26. . A first inlet hole 251h, into which city gas flows, is opened between the blind plug 27 and the first fuel jet 4A in the cylindrical gap portion 25a in the first boss portion 25. The relationship between the small hole diameter d and the minimum diameter D of the venturi V will be described later. A groove 44 is formed on the outer end surface of the first fuel jet 4A, and is configured to be rotatable for inserting a flathead screwdriver.

  In a tube 31 of the throttle body 3, a throttle 32 is fixedly mounted on a throttle shaft 33 which is pivotally supported, and is attached to be freely opened and closed. When idling is set to a very low rotational speed, the negative pressure in the venturi portion is small, so that the fuel is mainly supplied from the idle hole 34 opened where the negative pressure downstream of the throttle 32 is large [FIG. )reference〕.

The passage area is adjustable by an idle fuel flow rate adjusting needle 35. The rotation stop which becomes a resistance so that the needle 35 does not rotate during the operation of the engine is performed by a fixed spring 36. Alternatively, a lock nut may be used. In particular, when the idling speed is set to be low, the opening of the throttle 32 is small, so that fuel can be supplied even when a sufficient venturi negative pressure has not yet been generated in the process of opening the throttle 32. There is time to step hole 37 is opened port to the tube body 31 of the position where the the after flow slightly opened.

  The step hole 37 and the idle hole 34 are configured such that fuel can be supplied through a vertical through hole 38 communicating with the lower space 24 of the main body 2. The through hole 38 is a part that is continuous with the main body 2 and the throttle body 3. Further, the lower end of the through hole 38 is closed, and the outer end of the step hole 37 is also closed. The fuel may be controlled by the diameter of the step hole 37. In an engine for power generation, the idle speed i is often set to a normal speed or a slightly lower speed. In this case, the step hole 37, the needle 35, the fixed spring 36, and the idle hole 34 become unnecessary.

  Next, the gas supply switching valve 7 is provided with a city gas supply source 91 or an LPG (liquefied petroleum gas) supply source 92 of different types, and without mixing them, one of the gas fuels is surely passed through the mixer A. And supplies it to the gas engine 93 for power generation. The gas supply switching valve 7 includes a valve body 71, a valve body 72, and an operation unit 73 (see FIG. 8). In the valve body 71, a valve chamber 712 is formed inside a housing-shaped body body 711. The valve chamber 712 is a chamber in which a valve body 72 described later is arranged (see FIG. 8). The valve body 71 includes a main body side part 711a, a top part 711b, and a bottom part 711c. The main body side portion 711a, the top portion 711b, and the bottom portion 711c constitute a valve chamber 712 having a gap therein (see FIG. 8).

  An operation through hole 711d for connecting a valve body 72 and an operation lever, which will be described later, is provided at the top 711b of the body main body 711. The main body side portion 711a is a cylindrical, rectangular parallelepiped, or cubic cylindrical body. The valve chamber 712 is a cylindrical void chamber. The peripheral wall of the cylindrical main body side portion 711a is shared with the first inflow channel 713, the second inflow channel 714, and the common outflow channel 715, which are in the form of through holes that communicate the outside of the body body 711 and the valve chamber 712 therein. An inflow channel 716, a first outflow channel 717, and a second outflow channel 718 are provided (see FIG. 8).

  Further, in the common outflow passage 715, an outflow inner peripheral concave portion 715a is formed in a circumferential direction at an opening location on the inner peripheral side surface of the valve chamber 712 (see FIG. 8). The outflow inner peripheral concave portion 715 a is a portion formed as a concave groove along the circumferential direction on the inner peripheral side surface 712 a of the valve chamber 712, and communicates with the inner peripheral opening of the valve chamber 712 of the shared outflow passage 715. Then, in the rotation range of the valve body 72 in the switching operation, the outlet inner circumference 722m of the switching inflow passage 722 of the valve body 72 is always in a range that can communicate with the outlet inner circumferential recess 715a. The formation range of the concave portion 715a in the circumferential direction is set (see FIG. 8B).

  In the common inflow passage 716, an inflow inner peripheral concave portion 716a is formed in a circumferential direction at an opening position on the inner peripheral side surface 712a of the valve chamber 712 (see FIG. 8). The inflow inner peripheral concave portion 716 a is a portion formed as a concave groove along the circumferential direction on the inner peripheral side surface 712 a of the valve chamber 712, and communicates with the inner peripheral opening of the valve chamber 712 of the common inflow passage 716. Then, in the rotation range of the valve body 72 in the switching operation, the inflow inner circumference is set so that the opening 723m on the inlet side of the switching outflow passage 723 of the valve body 72 can always communicate with the inflow inner circumference concave portion 716a. The formation range of the concave portion 716a in the circumferential direction is set (see FIG. 8C).

  The first inflow channel 713, the second inflow channel 714, and the common outflow channel 715 are arranged and formed at positions near the top 711b side of the main body side portion 711a and on the same circumference. The first inflow channel 713 and the first outflow channel 717 have the same flow direction, and similarly, the second inflow channel 714 and the second outflow channel 718 have the same flow direction. [See FIGS. 8B and 8C]. The direction of the flow path of the set of the first inflow path 713 and the first outflow path 717 is different from the direction of the flow path of the set of the second inflow path 714 and the second outflow path 718.

  Specifically, the first inflow passage 713 and the first outflow passage 717 are located at positions different in angle by about 90 degrees at the center of the diameter of the valve chamber 712 having a circular cross section. Similarly, the second inflow channel 714 and the second outflow channel 718 are located at positions that differ by about 90 degrees in angle at the center of the diameter of the valve chamber 712 having a circular cross section. The directions of the flow paths in the common outflow channel 715 and the common inflow channel 716 are the same. A through-hole 711e for the operation unit 73 is formed in the top 711b. The first inflow channel 713 and the first outflow channel 717 have the same flow direction.

  The valve body 72 includes a valve body 721, a switching inflow path 722, and a switching outflow path 723. The switching inflow path 722 and the switching outflow path 723 are formed in the valve body 721 in such a positional relationship as to be displaced along the axis L (see FIG. 8A). The valve body 721 is formed in a cylindrical shape. An axial core L is set in the axial direction of the cylindrical valve body 721, and the valve body 721 is configured to be rotatable in the valve chamber 712 about the axial core L as a center of rotation. The outer periphery 721a of the valve body 721 of the valve body 72 is configured to be able to rotate smoothly while being in close contact with the inner peripheral side wall surface of the valve chamber 712 of the valve body 71.

  The valve main body 721 of the valve body 72 is provided with an operation unit 73. The operating section 73 serves to rotate the valve body 72 from outside the valve body 71 with respect to the valve body 71. The operation unit 73 includes an operation shaft 731 and an operation lever 732. The operation shaft 731 is a shaft member formed to protrude from one axial end of the valve main body 721 along the axial direction of the valve body 72.

  An operation lever 732 is provided at a shaft end of the operation shaft 731. The operation lever 732 includes a lever portion 732a and a lever boss portion 732b, and an operation shaft 731 penetrates the lever boss portion 732b, and both are fixed to each other. Specifically, a screw portion is provided in the vicinity of the shaft end of the operation shaft 731, and a nut 733 to be screwed with the screw portion is provided. The operation shaft 731 and the operation lever 732 are fixed by tightening the nut 733. Is done.

  The valve body 72 is disposed in the valve chamber 712 of the valve body 71. The valve body 72 can be rotated inside the valve chamber 712 of the valve body 71 by rotating the operation lever 732 from outside the valve body 71. By operating the operation lever 732 of the operation unit 73, the valve body 72 rotates around the axis L in the valve chamber 712.

  The axis L of the valve body 72 is a line that becomes a rotation center axis when the valve body 72 rotates inside the valve chamber 712 of the valve body 71. As described above, in the valve body 72, the switching inflow path 722 and the switching outflow path 723 are formed integrally with the valve body 721. Thus, the operator can switch the flow path between the first gas supply flow path P1 and the second gas supply flow path P2 with a single operation of the operation unit 73, and can prevent erroneous operation. It is.

  The gas supply switching valve 7 of the present invention is applied to a gas supply system of a power generation gas engine that operates by using two types of different gas fuels depending on the situation. First, a different type of gas (city gas or LPG) is switched and partitioned, and the required gas fuel is supplied to the power generation gas engine 93 via the mixer A. The gas supply switching valve 7 constitutes a first gas supply passage P1, a second gas supply passage P2, and a low-pressure adjustment passage Pc in the gas supply system.

  The first gas supply flow path P1 constitutes a supply flow path for supplying city gas from the city gas supply source 91 to the mixer A, and includes a first inflow path 713, a switching inflow path 722, a common outflow path 715, and a common outflow path 715. The inflow path 716, the switching outflow path 723, the first outflow path 717, and the first suction flow path 61 constitute a flow path (see FIGS. 4 and 5A). The second gas supply passage P2 constitutes a supply passage for supplying LPG (liquefied petroleum gas) from the LPG (liquefied petroleum gas) supply source 92 to the mixer A. The inflow path 722, the common outflow path 715, the common inflow path 716, the switching outflow path 723, the second outflow path 718, and the second suction flow path 62 constitute a flow path.

  Here, the city gas is supplied from pipes such as branch pipes and gas pipes. The LPG (liquefied petroleum gas) supply source 92 has a gas cylinder 92a filled with LPG (liquefied petroleum gas), and the gas cylinder 92a is installed. Further, the gas cylinder 92a is provided with a manual valve 92b. The LPG (liquefied petroleum gas) gas cylinder 92a is an emergency one in the event of an emergency when the supply of city gas is stopped, and can complement the period until the city gas is restored.

  Further, a low-pressure adjusting flow path Pc is provided between the common outflow path 715 and the common inflow path 716. A low-pressure adjusting valve 51 is provided in the low-pressure adjusting channel Pc. The low-pressure adjustment flow path Pc is a common flow path between the first gas supply flow path P1 and the second gas supply flow path P2. That is, both the first gas supply flow path P1 and the second gas supply flow path P2 have a common low-pressure adjustment flow path Pc (see FIGS. 4 and 5B).

  In other words, when the first gas supply channel P1 is selected by the gas supply switching valve 7, the low pressure adjustment channel Pc constitutes a part of the first gas supply channel P1. It is included in the channel (see FIG. 4A). When the second gas supply flow path P2 is selected, the low-pressure adjustment flow path Pc is included in a flow path that forms a part of the second gas supply flow path P2 (see FIG. 4B). Then, each gas from the city gas supply source 91 or the LPG (liquefied petroleum gas) supply source 92 passes through this low-pressure adjustment flow path Pc, is set to an appropriate pressure by the low-pressure adjustment valve 51, and Supply gas fuel to gas engine.

  Next, a configuration for the mixer A of the present invention to function as a part of the engine system will be described with reference to FIGS. The air taken in by the power generating gas engine 93 is filtered by the filter 97 a of the air cleaner 97 and is taken into the mixer A. However, since the airflow resistance of the filter 97a cannot be avoided, the pressure is slightly lower than the atmospheric pressure. Therefore, a pressure is detected by an absolute pressure sensor 821 made of a pressure-sensitive diode or the like, and a signal is sent to an ECU (engine control unit) 81 (hereinafter, referred to as “ECU 81”).

  Air from the air cleaner 97 and fuel from the low-pressure regulating valve 51 flow into the mixer A, where they are mixed and sucked into the gas generating engine 93 through the intake manifold 94. The exhaust gas enters the muffler (not shown) from the exhaust manifold 95 through the three-way catalyst 96, is silenced, and is discharged to the atmosphere.

  Next, a process until fuel (LPG) vaporized from the gas supply source flows into the mixer A will be described. In this description, the gas supply source is the LPG supply source 92. When the manual valve 92b, which is closed when the cylinder 92a of the LPG supply source 92 is replaced, is opened, the fuel in the cylinder 92a is reduced in pressure by the primary pressure reducing valve 92c and passes through the electromagnetic shut-off valve 52 to turn off the gas. Flows into the low pressure regulating valve 51. Here, in the case of LPG, at room temperature, most of the inside of the cylinder 92a is liquid and the internal pressure is about 10 atm. The pressure is reduced to several atmospheres (3.5 atmospheres or less) by the primary pressure reducing valve 92c. The fuel (LPG) at this pressure is regulated to the same pressure downstream of the filter 97 a by the electromagnetic low-pressure regulating valve 51 and supplied to the mixer A.

  Since the power generation gas engine 93 is for power generation, it is maintained at a steady speed (for example, 2400 rpm) regardless of the magnitude of the load. The control for keeping the rotation speed constant is performed by controlling the opening of the throttle 32 in FIGS. 6A and 6B. The opening degree of the throttle 32 is adjusted by a step motor type actuator 39 attached to the throttle shaft 33 by an electric output from the ECU 81 in accordance with a signal from the crank angle sensor 83 of the electromagnetic pickup.

  When the electric load increases, the required torque of the engine increases, and the resistance reduces the engine speed. The electrical signal of the rotation speed is always detected by the crank angle sensor 83 and sent to the ECU 81. When the ECU 81 determines that the rotation speed has become lower than the predetermined rotation speed, a signal is issued to the actuator 39 to open the throttle 32. The signal from the ECU 81 and the engine speed are also constantly detected by the ECU 81.

  The mixture required to maintain the engine speed constant is drawn from the mixer A of the present invention into the cylinder of the gas engine 93 for power generation via the intake manifold 94. Here, a broken line connected to the ECU 81 is a signal from each sensor, and a solid line signal output from the ECU 81 is an output signal for operating the actuator.

  Next, the electromagnetic shutoff valve 52 and the low pressure adjusting valve 51 will be described with reference to FIG. Note that members common to the shut-off valve 52 and the low-pressure regulating valve 51 have the same name. When the engine is started, the coils 51b and 52b of both solenoid valves are energized by the output from the ECU 81. The lines of magnetic force form a magnetic field that extends from the magnetic poles of the magnetic cores 51a and 52a to the movable iron cores (armatures) 51c and 52c of the magnetic material.

  As a result, the cores 51a and 52a attract the movable iron cores 51c and 52c. As a result, the movable iron cores 51c and 52c overcome the forces of the springs 51d and 52d, and open the fuel passage previously closed by the elastic sealing members 51e and 52e such as rubber. The shutoff valve 52 provided for safety is a simple on / off valve for the fuel passage, and the coils 51b and 52b are always energized while the power generating gas engine 93 is operating.

  An absolute pressure sensor 822 having the same characteristics as the absolute pressure sensor 821 mounted in the air cleaner 97 is mounted in a fuel chamber 51f provided in the low pressure regulating valve 51. The ECU 81 compares the signals from the two sensors. If the pressure in the absolute pressure sensor 822 is high, the power supply to the coil 51b is turned off.

When the fuel in the fuel chamber 51f is consumed by the mixer, the internal pressure of the fuel chamber 51f decreases, so that the coil 51b is energized to open the seal member 51e, and the fuel flows into the fuel chamber 51f. Thus the pressure of fuel supplied to the mixer can be one coercive the same as the pressure downstream of the air filter 97a of the air cleaner 97.

  Here, the time during which the fuel passage is shut off increases as the volume of the fuel chamber 51f increases, and the time during which the fuel throttle 51g is open decreases as the inner diameter increases. That is, the on / off time can be adjusted based on the volume of the fuel chamber 51f and the inner diameter of the fuel throttle 51g.

The principle by which the target air-fuel ratio (mass of intake air / mass of supplied fuel) can be obtained by the mixer having the structure shown in FIG. 1 will be described.
The following applies to both city gas and LPG (liquefied petroleum gas).
Air density ρ _A (kg / m ³ )
Fuel density ρ _F (kg / m ³ )
Venturi air velocity V _A (m / s)
Orifice fuel velocity v _F (m / s)
Venturi diameter D (m)
Orifice diameter d (m)
Mass _m A of air flowing per unit time (kg / s)
Mass of fuel flowing per unit time m _F (kg / s)
Air-fuel ratio _{A / F = m A / m} F
Then, the mass per unit time of the air flowing through the venturi is
m A _{= (the} area of the venturi section) × (air velocity venturi section) × (density of air)
= Π / 4 · D ² · V _A · ρ _A (kg / s)

Similarly, the mass of fuel flowing through the orifice per unit time is
^{_{m F = π / 4 · d}} 2 · V F · ρ F (kg / s)
Accordingly, the air-fuel ratio A / F = (π / 4 · D 2 · V A · ρ A) / (π / 4 · d 2 · V F · ρ F) =
_{^{(D 2 · V A · ρ}} A) / (d 2 · V F · ρ F) ···· (1)
On the other hand, the negative pressure P (Pa) generated in the venturi is calculated by Bernoulli's theorem.
P = 1/2 · ρ _A · V _A ² (Pa)
Becomes This negative pressure fills the space N around the venturi and becomes the negative pressure at the outlet of the orifice 43. That is, as described above, the pressure at the inlet of the orifice 43 is adjusted to be the same as the pressure of the air flowing into the mixer downstream of the air filter 97a of the air cleaner 97. Is the same P (= ρ · ρ _A · V _A ² ) (Pa) as the venturi negative pressure.
(P =) 1/2 · ρ _A · v _A ² = １ ／ · ρ _F · v _F ²

（２）を（１）のＶ_Ｆに代入して整理すると、

Than this,

(2) a and rearranging are substituted into _{V F} (1),

は一定となり、空然比は一義的にベンチュリ最狭部の径の二乗とオリフィス径の二乗の比で決まる。 As described above, if the density of air and gaseous fuel is determined, an arbitrary air-fuel ratio can be obtained by a selective combination of the venturi diameter and the orifice diameter.
That is, if the pressure is constant, ρ _A and ρ _F are constants, that is, constants because they are physical property values. Therefore

Is constant, and the air ratio is uniquely determined by the ratio of the square of the diameter of the narrowest part of the venturi to the square of the diameter of the orifice.

これよりオリフィス径ｄ1は８.４１mmとなる。 Hereinafter, the orifice diameter d1 of the first fuel jet 4A for city gas and the orifice diameter d2 of the second fuel jet 4B for LPG (liquefied petroleum gas) are determined. First, in the case of city gas (methane CH ₄ ), the orifice diameter d1 for designing a mixer that maintains the air-fuel ratio at 16.8, which is the stoichiometric air-fuel ratio of city gas, is determined.
If the venturi diameter D is 30 mm, the density of city gas is ρ. ^{= 0.714 (kg / m 3)} , when the density of the air and ρ _A = 1.25kg / ^{m 3,}

Thus, the orifice diameter d1 is 8.41 mm.

これよりオリフィス径ｄ2は６.７９mmとなる。 Next, in the case of LPG (liquefied petroleum gas, propane C ₃ H ₈ ), the orifice diameter d2 for designing a mixer that maintains this air-fuel ratio at 15.6 which is the theoretical air-fuel ratio of LPG (propane) is determined.
When the venturi diameter D = 30 mm, the density of LPG is ρ. = 1.96 (kg / m3), when the density of the air and ρ _A = 1.25kg / ^{m 3,}

Thus, the orifice diameter d2 is 6.79 mm.

となる。このように、都市ガス燃料用の第１燃料ジェット４Aのオリフィス４３の直径ｄ1は、ＬＰＧ(液化石油ガス)燃料用の第２燃料ジェット４Bのオリフィス４３の直径ｄ2よりもい大きい。 From the above, the magnitude relationship between the orifice diameter d1 of the first fuel jet 4A and the orifice diameter d2 of the second fuel jet 4B is

Becomes Thus, the diameter d1 of the orifice 43 of the first fuel jet 4A for city gas fuel is larger than the diameter d2 of the orifice 43 of the second fuel jet 4B for LPG (liquefied petroleum gas) fuel.

  FIG. 9 shows the control characteristics of the air-fuel ratio when the mixer A of the present invention is mounted on an 860 cc two-cylinder LPG engine. The rotation speed was 2400 rpm, and the idling rotation speed at the time of the experiment was 900 rpm. The interval H between the annular slits S is formed by slightly shortening the end of the upper body 1 (see FIG. 1A). Alternatively, the end of the main body 2 may be cut to form the gap H without cutting off the end of the upper body 1. Furthermore, both may be cut out little by little.

  The horizontal axis in FIG. 8 is the throttle opening, and the vertical axis is the excess air ratio. The excess air ratio is a value obtained by dividing the air-fuel ratio at that time by the stoichiometric air-fuel ratio. When 1 is the stoichiometric air-fuel ratio, it means that the air is more mixed and the air-fuel mixture is thinner. Conversely, if it is smaller than 1, it means that the air is in short supply, that is, it is dense. A mixer equipped with an orifice calculated to have a stoichiometric air-fuel ratio as described above has a target stoichiometric air-fuel ratio from a medium load to a full load at a throttle opening of 30 ° or more at which a sufficient pressure of a Betchuri is generated. You can see that it is maintained.

  However, without the idle adjustment and the step hole 37, the excess air ratio increases in a region where the negative pressure of the venturi is small and fuel cannot be sucked out. That is, it becomes thinner than the stoichiometric air-fuel ratio. With the idle adjust and the step hole, the target air-fuel ratio is maintained close to the target air-fuel ratio even in a place where the throttle opening is small as shown by the broken line.

Here, the relationship between the inner diameter D of the venturi shown in FIG. 1, the annular slit S, and the orifice 43 shown in FIGS. 1 and 6A will be described. The area of the annular slit S through which the gas fuel passes is πD × H (m ² ). H of the induction type is the interval between the annular slits S. If this is not larger than the passage area of the orifice 43, the area of the annular slit S becomes rate-determining, and the orifice 43 cannot exert the throttle effect.

When this is made into the formula,
π × D × H ≧ π / 4 · (d1 or d2) ²
That is, H ≧ (d1 or d2) ² / 4D.
Conversely, if it is too large, the fuel will flow from a part of the annular slit S instead of the entire circumference, and the mixing with the air will be poor. Therefore, as a range (interval H) of the annular slit S,
1.5x (d1 or ^{d2) 2/4 · D ≧} H ≧ (d1 or ^d2) 2/4 · D
It is good to do.
When the value of the hole diameter d of the orifice is different from that of the city gas and the LPG, the larger value is used as the value of this equation (the larger the value of the city gas). This is because the area of the slit is always larger than the area of the orifice so that the minimum passage area is the orifice portion.

  In the case of an engine with a small engine displacement (300 cc or less), if the idling speed is slightly increased, an excess air ratio of about 1 can be maintained even at a low load without idle adjustment and a step hole.

In order to absorb subtle changes in the air-fuel ratio due to changes in altitude and temperature, clogging of air filters, and the accuracy of parts, etc. and detecting an air-natural ratio in the O ₂ sensor 84 mounted, performs feedback control.

  If it is thin, the energization time to the coil 51b is increased so that the absolute pressure in the fuel chamber 51f detected by the actuator becomes higher than the absolute pressure of the air at the inlet of the mixer detected by the absolute pressure sensor 82. Conversely, if the fuel density is high, the time for energizing the coil 51b is reduced so that the absolute pressure in the fuel chamber 51f is reduced. This further improves the accuracy of maintaining the theoretical air-fuel ratio.

  A description will be given of a simple structure in which an annular slit S is formed all around the narrowest portion diameter D of the Venturi V in order to uniformly mix LPG of fuel with air. In FIG. 1, the structure in which the peripheral edge of the contraction portion 12 of the upper body 1 is slightly recessed to form the annular slit S has been described. The annular slit S has a functional relationship with the smallest diameter D of the venturi V and the orifice diameter d1 or d2 of the orifice 43.

  If the fuel orifice diameter d1 of the first fuel jet 4A or the orifice diameter d2 of the second fuel jet 4B is increased to enrich the fuel, it is necessary to widen the annular slit S as well. That is, the gap H is widened. The same applies when the Venturi V is increased to increase the output. Furthermore, processing cost is required to make the center of the upper body 1 more accurate than the surroundings. In addition, if the cutting is performed too deeply, the surroundings are cut, and if the cutting is performed consistently, it takes time to process.

  A second embodiment of the present invention will be described with reference to FIGS. First, both the upper body 1 and the main body 2 are flattened at the same height as the periphery of the Venturi V portion, and a spacer 19 having a thickness t in the form of a gasket as shown in FIGS. Then, an interval H between the annular slits S is created. At this time, the interval H is set to the thickness t.

  Further, in the thickness t of the spacer 19, appropriate thicknesses t1, t2, t3 and the like having different thicknesses t are often arranged to enable fine adjustment (see FIG. 3C). Further, the spacer 19 may be made of a thin plate of stainless steel or aluminum. In the spacer 19, the inner diameter portion 19a is formed to have the same diameter as the outer shape of the annular space N.

  The outer portion 19b of the spacer 19 is formed to have the same or substantially the same outer cross-sectional shape as the lower end of the upper body 1 or the upper end of the main body 2 (see FIGS. 2 and 3). Although a plan view of the upper body 1 is omitted in FIG. 2, it has the same shape as the upper body 1 shown in FIG. Specifically, if the shape of the lower end portion of the upper body 1 is substantially elliptical, the outer portion 19b of the spacer 19 is also substantially elliptical. If the shape of the lower end portion of the upper body 1 is a substantially rectangular shape such as a square or a rectangle, the outer shape portion 19b of the spacer 19 is also a substantially similar rectangular shape.

  If gas leakage is a concern, a thin liquid packing may be applied between the spacer 19 and the upper body 1 and the main body 2. Further, an O-ring may be formed by digging a ground groove on the lower surface of the upper body 1 and the upper surface of the main body 2. While maintaining a constant ratio of the square of the diameter of the narrowest part of the venturi and the square of the diameter of the orifice, the fuel is supplied so as to have a target air-fuel ratio, and the annular slit is formed so that the air and the fuel are homogeneously mixed. The area may be equal to or less than 1.5 times the area of the orifice diameter.

  Next, the configuration of a gas supply system of a power generating gas engine 93 including the mixer A of the present invention will be described (see FIGS. 4 and 5). This system includes an ECU 81, and a valve body 71 of the gas supply switching valve 7 is provided with a gas discriminating sensor 85 for discriminating the type of gas fuel circulating. The ECU 81 uses the gas discrimination sensor 85 to determine the type of gas, that is, whether the gas is city gas or LPG (liquefied petroleum gas).

  In the present invention, a city gas supply source 91 and an LPG (liquefied petroleum gas) supply source 92 are provided in the system. The gas supply switching valve 7 is in communication with both the city gas supply source 91 and the LPG (liquefied petroleum gas) supply source 92. By switching the operation lever 732 of the operation unit 73 of the gas supply switching valve 7, The flow path is switched and partitioned so that only one of the first gas supply flow path P1 and the second gas supply flow path P2 is opened, and the other is shut off. The operation of the operation lever 732 of the operation unit 73 in the gas supply switching valve 7 is manually performed by an operator.

  Here, the first gas supply passage P1 is dedicated to city gas, and the second gas supply passage P2 is dedicated to LPG (liquefied petroleum gas). Normally, city gas is used for the power generation gas engine 93, the gas supply switching valve 7 opens the first gas supply passage P 1, and the city gas passes through the first inlet 251 of the mixer A. The gas is supplied to the power generating gas engine 93 via the power supply. Then, in the normal state, the gas supply switching valve 7 keeps the second gas supply passage P2 shut off (see FIGS. 4A and 4B).

  In an emergency, city gas will be shut down. The emergency is specifically when a disaster such as an earthquake occurs. At this time, the manual valve 92b of the gas cylinder 92a of the LPG (liquefied petroleum gas) supply source 92 is opened, and then the operation lever 732 of the operation section 73 of the gas supply switching valve 7 is operated to switch the first gas supply flow path P1 from the first gas supply flow path P1. Switching to the second gas supply channel P2, the first gas supply channel P1 is shut off, and the second gas supply channel P2 is opened. As a result, LPG (liquefied petroleum gas) is supplied to the gas engine 93 for power generation via the second inlet 261 of the mixer A.

  Then, in the power generating gas engine 93, normally, the air taken in by the power generating gas engine 93 is filtered by a filter 97a of an air cleaner 97 (not shown) and then sucked into the mixer A. In the mixer A, the gas depressurized by passing either the city gas or LPG (liquefied petroleum gas) separated by the switching operation of the gas supply switching valve 7 through the low pressure regulating valve 51 of the low pressure regulating flow path Pc. The fuel flows in, where it is mixed and drawn into the engine 7 through the intake manifold 71. Exhaust gas enters the muffler (not shown) from the exhaust manifold 71 through the three-way catalyst 96, is silenced, and is emitted to the atmosphere.

  Although the present invention has been described for use in a gas engine for power generation, the present mixer has a simple structure, and the air-fuel ratio of the air-fuel mixture sucked by the gas engine is set to the stoichiometric air-fuel ratio (16.8 for city gas, propane In the case of, it is 15.6). Even without complicated control, harmful components HC (hydrocarbon), CO (carbon monoxide) and NOx (nitrogen oxide) in exhaust gas are simultaneously emitted by the mixer and the three-way catalyst 96 disposed in the exhaust system. Since it can be greatly reduced, it can also be used for gas engines for automobiles.

DESCRIPTION OF SYMBOLS 1 ... Upper body, 12 ... Contraction part, 14 ... Upper space, 19 ... Spacer,
2 ... main body, 21 ... lower space, 22 ... diffusion part, 25 ... first boss part,
251, a first inlet portion, 26, a second boss portion, 261, a second inlet portion, 3, a throttle body, 32, a throttle, 4A, a first fuel jet, 4B, a second fuel jet,
51: low pressure regulating valve, 7: gas supply switching valve, 71: valve body,
713: first inflow channel, 714: second inflow channel, 717: first outflow channel, 718: second outflow channel,
72: valve element, 73: operation unit, 81: ECU, 85: gas discrimination sensor,
91: city gas supply source, 92: LPG supply source, 93: gas engine for power generation,
V: Venturi, N: annular space, S: annular slit.

Claims (9)

An upper body having a Venturi contraction portion formed below the external air introduction pipe portion and having an inverted U-shaped annular upper space provided outside the contraction portion; the outer diffusion of successive venturi is provided a lower space of the U-shaped annular, and the lower part space for the first inlet and the first fuel jet and LPG fuel for town gas fuel from the outer periphery A main body provided with a second inlet portion and a second fuel jet, an annular space having an O-shaped cross section including the lower space and the upper space, and a throttle body provided with a throttle continuously to the main body; An annular slit as a gap is formed at a narrowest portion of the venturi between the contraction portion and an end portion periphery of the diffusion portion, and the first fuel jet and the second The exit side of the fuel jet is Mixer power generation gas engine, characterized by comprising communicating with the body.   The mixer for a power generating gas engine according to claim 1, wherein a gap between the annular slits as the gap is a constant interval.   2. The mixer for a power generating gas engine according to claim 1, wherein a gap of said annular slit as said gap is a variable interval.   4. The mixer structure for a power generating gas engine according to claim 1, wherein a spacer having an appropriate thickness is interposed in the gap of the annular slit as the gap, and an inner diameter portion of the spacer is formed in the annular space. A mixer for a gas engine for power generation, wherein the mixer is formed to have the same diameter as the outer shape, and the outer portion is formed to have the same outer cross-sectional shape as the lower end of the upper body. 5. The mixer structure for a gas engine for power generation according to claim 1, wherein the ratio of the square of the diameter of the narrowest portion of the venturi to the square of the orifice diameter of the first fuel jet and the second fuel jet is set. 6. A mixer for a gas engine for power generation, characterized in that it is kept constant.   6. The mixer structure for a gas engine for power generation according to claim 1, wherein a first boss portion and a second boss portion are formed on an outer peripheral side of the main body, and the first boss portion is formed on the first boss portion. Is provided with the first inlet portion and the first fuel jet, and the second boss portion is provided with the second inlet portion and the second fuel jet, and is provided on an outer periphery of the main body and in a radial direction of the venturi. The power supply gas engine mixer is provided at a position on both sides or on the outer circumference. A gas engine for power generation that can use city gas and LPG, and a Venturi contraction part formed below the external air introduction pipe, and an inverted U-shaped annular upper part is formed outside the contraction part. an upper body space is provided, on the outside of the diffusion part of the venturi continuous with the contraction flow portion is provided lower space of the U-shaped annular, and the lower part space for the city gas fuel from the outer periphery A main body including a first inlet, a first fuel jet and a second inlet for the LPG fuel and a second fuel jet, an annular space having an O-shaped cross section including the lower space and the upper space, An annular slit as a gap is provided at a narrowest portion of the venturi between the contraction portion and an end peripheral edge of the diffusion portion, the throttle body having a throttle body provided continuously with the main body. And the first fuel Outlets of the jet and the second fuel jet are connected to the main body, a mixer, a city gas supply source, an LPG supply source, a valve chamber, and a first inflow passage through which city gas flows in and out. An outflow path, a valve body having a second inflow path and a second outflow path through which LPG flows in and out, and a flow path housed in the valve body and formed by the first inflow path and the first outflow path, or A gas supply switching valve having a valve body that opens one of the flow paths formed by the second inflow path and the second outflow path and shuts off the other, and a second one of the city gas supply source and the mixer A first inlet portion is communicated with the first inflow passage of the gas supply switching valve via the first outflow passage, and the LPG supply source and a second inlet portion of the mixer are connected to the second inlet portion of the gas supply switching valve. (2) Link through the inflow channel and the first outflow channel Gas supply system of the power generation gas engine, characterized by comprising a.   8. The gas supply system for a gas engine for power generation according to claim 7, further comprising an ECU and a low-pressure regulating valve, wherein the low-pressure regulating valve operates so as to have an appropriate pressure according to a gas type according to a command from the ECU. A gas supply system for a power generation gas engine. The gas supply system for a gas engine for power generation according to claim 7 or 8, further comprising an ECU, a gas supply switching valve being provided with a gas discrimination sensor, being connected to the ECU, and passing through the gas supply switching valve. A gas supply system for a power generation gas engine, wherein a species is determined by the gas determination sensor and the ECU.

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