JP2013060836A - Fuel supply device for gas engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel supply device for a gas engine, configured to immediately start and actuate the gas engine without preheating a fuel passage by an electric heater even in a low-temperature condition where it is difficult to gasify a liquefied fuel.SOLUTION: To a fuel cylinder 15, a first fuel passage for supplying a fuel delivered therefrom and converted into a gas phase to a mixer, and a second fuel passage 19 for supplying a liquid-phase fuel delivered from the fuel cylinder 15 to the mixer 3 are connected in parallel to each other; a first gas phase/liquid phase operation switching valve 22 which is normally closed, and is opened when the temperature of a gas engine is set above a predetermined value is interposed in the first fuel passage 18; and a second gas phase/liquid phase operation switching valve 42 which is opened at the start and during operation of the gas engine E, and is closed upon opening of the first gas phase/liquid phase operation switching valve 22 is interposed in the second fuel passage 19.

Description

  The present invention includes a fuel cylinder filled with liquefied fuel, a mixer for supplying an air-fuel mixture to a gas engine, a fuel passage for supplying fuel that has been sent from the fuel cylinder into a gas phase to the mixer, and the fuel passage And a fuel supply device for a gas engine provided with a decompression device for decompressing the fuel in the gas phase.

  Conventionally, such a fuel supply device for a gas engine is already known as disclosed in Patent Document 1 below.

JP 2011-85115 A

  In such a conventional fuel supply device, when the gas engine is operated in a low temperature state where it is difficult to vaporize the liquefied fuel, the fuel passage is preheated by an electric heater operated by battery power, and the liquid phase fuel passing through the fuel passage I am trying to vaporize.

  In such a case, the installation of the battery and the electric heater increases the cost, and since it takes time to vaporize the liquid phase fuel in the first fuel passage due to the heating by the electric heater, the gas engine is started immediately. There is an inconvenience that cannot be done.

  The present invention has been made in view of such circumstances. Even in a low temperature state where vaporization of liquefied fuel is difficult, the gas engine can be immediately started and operated without preheating the fuel passage by an electric heater. An object of the present invention is to provide a fuel supply device for a gas engine.

  In order to achieve the above object, the present invention provides a fuel cylinder filled with liquefied fuel, a mixer for supplying an air-fuel mixture to a gas engine, and a fuel which is sent from the fuel cylinder and becomes a gas phase to the mixer. In the fuel supply device for a gas engine, which is provided in the first fuel passage and is provided in the first fuel passage and depressurizes the fuel in the gas phase, the liquid-phase fuel delivered from the fuel cylinder is A second fuel passage for supplying to the mixer is provided in parallel with the first fuel passage, and the first fuel passage is normally closed, and is opened when the gas engine temperature exceeds a predetermined temperature. While interposing a phase / liquid phase operation switching valve, the second fuel passage is opened when the gas engine is started and operated, but in conjunction with the opening of the first gas phase / liquid phase operation switching valve. Second gas phase / liquid phase operation switching to close It has interposed a first said.

  According to the present invention, in addition to the first feature, the decompression device comprises a decompression valve that decompresses the gas-phase fuel passing therethrough to a predetermined pressure by opening the first gas-phase / liquid-phase operation switching valve; A zero governor configured to depressurize the fuel decompressed by the decompression valve to approximately atmospheric pressure and supply the fuel to the mixer. The second gas phase / liquid phase operation switching valve is a gas phase fuel delivered from the decompression valve. A second feature is that the valve is closed in response to the predetermined pressure.

  Further, in addition to the first or second feature, the present invention provides that the second gas phase / liquid phase operation switching valve starts the gas engine when the first gas phase / liquid phase operation switching valve is closed. A third feature is that the valve is configured to open by receiving a negative pressure generated in the crank chamber during operation.

  In addition to the first feature, the present invention further includes a fuel flow rate control valve for controlling the fuel flow rate in the second fuel passage in inverse proportion to the vapor pressure in the fuel cylinder. The intervening feature is the fourth feature.

  In addition to the fourth feature of the present invention, the fuel flow rate control valve increases the fuel flow rate in the second fuel passage according to an increase in the venturi negative pressure generated in the venturi portion of the mixer. The fifth feature is to be configured as follows.

  In addition to the fourth feature of the present invention, the second fuel passage further includes a second fuel passage for controlling a fuel flow rate in the second fuel passage in proportion to an opening of a throttle valve of the mixer. A sixth feature is that a flow control valve is interposed.

  In addition to the first feature, the present invention provides a fuel injection valve capable of injecting liquid phase fuel in the second fuel passage into the mixer when the second gas phase / liquid phase operation switching valve is opened. A seventh feature is that an electronic control unit for controlling the fuel injection amount of the fuel injection valve according to the operating state of the gas engine is connected to the fuel injection valve.

  According to the first feature of the present invention, when the gas phase fuel is difficult to be supplied to the gas engine at a low temperature, the first gas phase / liquid phase operation switching valve is closed to open the first fuel passage. On the other hand, when the gas engine is started, the second gas phase / liquid phase operation switching valve is opened and the second fuel passage is conducted, so that the liquid phase fuel in the fuel cylinder is supplied to the mixer through the second fuel passage. , The gas engine starts and warms up. Thus, since the gas engine can be started and warmed up with liquid phase fuel, the low temperature region in which the gas engine can be operated can be greatly expanded. Therefore, it is possible to immediately start and operate the gas engine without preheating the first fuel passage by the electric heater.

  When the gas engine temperature reaches a predetermined temperature due to the warm-up operation of the gas engine, the second gas phase / liquid phase operation switching valve is closed to shut off the second fuel passage, while the first gas phase / liquid phase operation switching is performed. Since the valve is opened and the first fuel passage is conducted, the fuel that has exited the fuel cylinder is heated by the muffler and the gas engine while passing through the first fuel passage to be converted into a gas-phase fuel, and then the first gas passage. After passing through the phase / liquid phase operation switching valve, the pressure is reduced by the speed reducer and supplied to the mixer. In this way, the gas engine is smoothly switched from operation with liquid phase fuel to operation with gas phase fuel, and the original low fuel consumption is ensured.

  According to the second feature of the present invention, the second gas phase / liquid phase operation switching valve has a predetermined gas phase fuel delivered from the pressure reducing valve when the first gas phase / liquid phase operation switching valve is opened. Since the valve is closed under pressure, the second gas phase / liquid phase operation switching valve can be closed with a simple structure in conjunction with the opening of the first gas phase / liquid phase operation switching valve.

  According to the third feature of the present invention, the second gas phase / liquid phase operation switching valve, which is normally closed at a low temperature, can be opened in conjunction with the starting operation of the gas engine. Startup and operation with liquid fuel can be made possible.

  According to the fourth aspect of the present invention, the amount of liquid-phase fuel supplied from the second fuel passage to the mixer can be controlled in inverse proportion to the vapor pressure in the fuel cylinder, and the empty air-fuel mixture generated by the mixer can be controlled. It is possible to optimize the fuel ratio.

  According to the fifth aspect of the present invention, in addition to controlling the amount of liquid-phase fuel supplied from the second fuel passage to the mixer in inverse proportion to the vapor pressure in the fuel cylinder, the amount of liquid-phase fuel supplied is controlled by the venturi. It can be controlled so as to increase in accordance with the rise of the venturi negative pressure generated in the section, whereby the air-fuel ratio of the air-fuel mixture generated by the mixer can be further optimized.

  According to the sixth aspect of the present invention, in addition to controlling the amount of liquid phase fuel supplied from the second fuel passage to the mixer in inverse proportion to the vapor pressure in the fuel cylinder, the amount of liquid phase fuel supplied is throttled. Control can be performed in proportion to the opening of the valve, thereby further optimizing the air-fuel ratio of the air-fuel mixture generated by the mixer.

  According to the seventh aspect of the present invention, at the start and operation of the gas engine with the liquid phase fuel, the fuel injection amount to the mixer is finely controlled according to the operation state of the gas engine, and the gas engine is controlled from its idling. It is possible to supply an air-fuel mixture with an appropriate air-fuel ratio over a wide operating range up to load operation, which can contribute to improvements in output performance and fuel efficiency.

1 is a schematic diagram of a fuel supply device for a gas engine according to a first embodiment of the present invention. The schematic diagram of the fuel supply apparatus for gas engines which concerns on 2nd Embodiment of this invention. The schematic diagram of the fuel supply apparatus for gas engines which concerns on 3rd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  First, the first embodiment of the present invention shown in FIG. 1 will be described. The gas engine E is equipped with a mixer 3 having an intake passage 2 communicating with the intake port. The mixer 3 is connected to an air cleaner 4 for filtering intake air passing through the intake passage 2. The throttle valve 5 that opens and closes downstream of the venturi 2a is pivotally supported. The gas engine E is used to drive a generator and various work machines.

  A muffler 6 is connected to the exhaust pipe 6 of the gas engine E, and an alternator 8 and a recoil type starter 9 are attached to a crankshaft (not shown) of the gas engine E.

  The mixer 3 includes first and second main nozzles 11 and 12 that open to the venturi portion 2 a of the intake passage 2, and an idle that branches from the second main nozzle 12 and opens to the intake passage 2 downstream of the throttle valve 5. Port 13 is provided.

  The fuel supply device S of the present invention is connected to the first and second main nozzles 11 and 12. This fuel supply device S is connected to a cassette type fuel cylinder 15 liquefied and packed with gas fuel such as butane and propane, and a main fuel passage 16 opened and closed by a manual cock 17 is connected to the fuel cylinder 15. A first fuel passage 18 and a second fuel passage 19 are connected in parallel to the fuel passage 16. The fuel cylinder 15 is accommodated in the heat insulating case 14.

  An automatic opening / closing valve 20, a first gas phase / liquid phase operation switching valve 22, and a pressure reducing valve 23 are sequentially inserted in the first fuel passage 18 from the upstream side. A downstream end of the first fuel passage 18 is connected to a zero governor 24 provided in the mixer 3. The zero governor 24 is disposed in a zero governor chamber 25 formed in the mixer 3, and an upstream end of the first main nozzle 11 is opened in the zero governor chamber 25. The first fuel passage 18 is disposed close to the muffler 6 so as to be heated by the radiant heat of the muffler 6 on the upstream side of the first gas phase / liquid phase operation switching valve 22.

  The automatic open / close valve 20 is configured as a negative pressure responsive type, and a first negative pressure transmission passage 21 extending from the crank chamber 10 of the gas engine E is connected to an operating portion thereof. The negative pressure generated in the chamber 10 is taken in and automatically opened.

  The first gas phase / liquid phase operation switching valve 22 is provided with a first valve housing 27 attached to a high temperature portion of the gas engine E, for example, a cylinder head. The chamber 28, the valve spring chamber 29, the fuel inlet chamber 30, and the fuel outlet chamber 31 are formed coaxially. The cylinder chamber 28 is divided into an upper temperature-sensitive chamber 33 and a lower atmospheric chamber 34 by a temperature-sensitive piston 32 slidably fitted therein. The thermal chamber 33 is provided with a thermal expansion material 35 such as wax. Enclosed.

  The partition wall between the fuel inlet chamber 30 and the fuel outlet chamber 31 includes a valve hole 37 communicating between the chambers 30 and 31, and a valve seat 38 surrounding the valve hole 37 and protruding toward the fuel inlet chamber 30. The valve rod 36 that penetrates the valve hole 37 is coupled to a valve body 39 that opens and closes the valve hole 37 in cooperation with the valve seat 38. The valve rod 36 is further slidably passed through the partition walls between the cylinder chamber 28, the valve spring chamber 29 and the fuel outlet chamber 31 so as to be in contact with the lower surface of the temperature-sensitive piston 32. A valve spring 40 that biases the rod 36 in the valve closing direction of the valve body 39, that is, in the seating direction with the valve seat 38, is accommodated in the valve spring chamber 29.

  The first gas phase / liquid phase operation switching valve 22 is attached to a high temperature portion of the gas engine E, such as a cylinder head, and is heated from the gas engine E. Further, when the thermal expansion material 35 is heated to a predetermined temperature at which gas-phase fuel can be supplied to the gas engine E (for example, 5 ° C. to 10 ° C. in the case of butane), the thermal expansion piston 35 is moved by thermal expansion. The valve body 39 is opened by pressing against the urging force of the valve spring 40, and the valve body 39 is closed by the urging force of the valve spring 40 when the thermal expansion material 35 is below the predetermined temperature. It has become. When the valve body 39 is opened, the vapor phase fuel moves from the fuel inlet chamber 30 to the fuel outlet chamber 31 through the valve hole 37 and heads toward the pressure reducing valve 23.

  The pressure reducing valve 23 is a known one, and its inlet communicates with the fuel outlet chamber 31 so that the pressure of the gas phase fuel exiting the fuel outlet chamber 31 is reduced to a predetermined pressure of, for example, 10 kPa. .

  The zero governor 24 is also a known one, and the pressure of the gas-phase fuel decompressed by the pressure reducing valve 23 is reduced to approximately atmospheric pressure. Therefore, when the valve element 39 is opened, the zero governor chamber 25 is filled with the vapor fuel at substantially atmospheric pressure. The pressure reducing valve 23 and the zero governor 24 constitute a pressure reducing device.

  The second fuel passage 19 is connected to the second main nozzle 12, and the second gas phase / liquid phase operation switching is performed to control the fuel supply cut-off from the second fuel passage 19 to the second main nozzle 12. A valve 42 and a fuel flow rate control valve 43 that controls the flow rate of fuel supplied to the second main nozzle 12 are disposed in the mixer 3.

  The second gas phase / liquid phase operation switching valve 42 includes a second valve housing 44 formed on one side of the mixer 3, and the second valve housing 44 includes a first diaphragm chamber 45 and an outer side thereof. And a second diaphragm chamber 46 adjacent thereto. The first diaphragm chamber 45 is provided with a first diaphragm 49 that divides the inside into an inner (mixer 3 side) spring chamber 48 and an outer first pressure receiving chamber 47, and the second diaphragm 49 includes a second diaphragm 49. A piston valve 54 that opens and closes a portion of the fuel passage 19 passing through the mixer 3 is connected. The first pressure receiving chamber 47 is connected to a pressure transmission passage 53 branched from the first fuel passage 18 downstream from the pressure reducing valve 23 so that the outlet pressure of the pressure reducing valve 23 is supplied to the first pressure receiving chamber 47. It has become. The spring chamber 48 accommodates a valve opening spring 55 that urges the piston valve 54 in the opening direction via the first diaphragm 49.

  The second diaphragm chamber 46 is provided with a second diaphragm 52 that divides the interior of the second diaphragm chamber 46 into an inner atmosphere chamber 50 and an outer second pressure receiving chamber 51, and the first and second diaphragm chambers are provided on the second diaphragm 52. An actuating rod 56 that slidably penetrates the partition wall 44 and 45 and contacts the rear end of the piston valve 54 so as to be separable is connected. The second pressure receiving chamber 51 accommodates a valve closing spring 57 that biases the operating rod 56 in the closing direction of the piston valve 54 via the second diaphragm 52. Further, the second pressure receiving chamber 51 is connected to a second negative pressure transmission passage 58 extending from the crank chamber 10 of the gas engine E, and takes in the negative pressure generated in the crank chamber 10 when the gas engine E is started and operated. The second diaphragm 52 is displaced in the retracting direction of the operating rod 56 against the set load of the valve closing spring 57.

  In the above, the set load of the valve closing spring 57 is set larger than the set load of the valve opening spring 55.

  The fuel flow control valve 43 includes a main jet 61 that connects the second fuel passage 19 in the mixer 3 and the second main nozzle 12, and a needle valve 62 that adjusts the opening area of the main jet 61. The needle valve 62 is connected to a control piston 64 slidably fitted in a cylinder chamber 63 formed in the mixer 3. The cylinder chamber 63 is partitioned by the control piston 64 into a spring chamber 65 and a third pressure receiving chamber 66 communicating with the second fuel passage 19, and the control piston 64 is placed on the third pressure receiving chamber 66 side in the spring chamber 65. A biasing control spring 67 is accommodated. Further, the cylinder chamber 63 is provided with stoppers 68 and 69 that define the lowering and raising limits of the control piston 64.

  The mixer 3 is further provided with a diaphragm chamber 70 adjacent to the lower side of the cylinder chamber 63. The diaphragm chamber 70 is provided with a diaphragm 73 that divides the inside into an upper atmosphere chamber 71 and a lower pressure receiving chamber 72. The pressure receiving chamber 72 is connected to the venturi portion 2 a of the intake passage 2 through a venturi negative pressure transmission passage 74. The diaphragm 73 is connected to a piston rod 75 extending from the control piston 64 and slidably passing through a partition between the cylinder chamber 28 and the diaphragm chamber 70.

  Next, the operation of the first embodiment will be described.

  When the gas engine E is operated, first, the cassette-type fuel cylinder 15 heated to room temperature or body temperature is accommodated in the heat insulating case 14 and the fuel cock 17 is opened.

  It is assumed that the gas phase fuel supply to the gas engine E is difficult at a low temperature. In this case, in the first gas phase / liquid phase operation switching valve 22, the thermal expansion material 35 contracts and the temperature-sensitive piston 32 rises, and the valve spring 40 pushes up the valve rod 36 by its urging force to cause the valve body. 39 is closed. As a result, the first fuel passage 18 is cut off. Therefore, since the outlet pressure of the pressure reducing valve 23 located downstream from the first gas phase / liquid phase operation switching valve 22 is atmospheric pressure, the second pressure communicating with the outlet of the pressure reducing valve 23 via the pressure transmission passage 53 is provided. The first pressure receiving chamber 47 of the gas phase / liquid phase operation switching valve 42 also becomes atmospheric pressure. Along with this, the valve opening spring 55 is urged to open the piston valve 54 via the first diaphragm 49 by its urging force, but the set load of the valve opening spring 55 is smaller than the set load of the valve closing spring 57. Therefore, at this stage, the piston valve 54 is still kept closed.

  On the other hand, the third pressure received by the fuel flow control valve 43 is transmitted through the second fuel passage 19 by the opening of the manual cock 17, and the control piston 64 receives the pressing force by the vapor pressure. The needle valve 62 is moved to a position where the load of the control spring 67 is balanced, and the opening degree of the main jet 61 is controlled to an opening degree suitable for starting and operation of the gas engine E.

  Therefore, when the manual cock 17 is opened and the recoil type starter 9 is operated in order to start the gas engine E, the negative pressure generated in the crank chamber 10 of the gas engine E causes the second gas phase / liquid phase operation switching valve 42 to operate. Since it transmits to the 2nd pressure receiving chamber 51, the 2nd diaphragm 52 is displaced against the urging | biasing force of the valve-closing spring 57, and the actuating rod 56 is retracted, The piston valve 54 is opened by the urging force of the valve-opening spring 55. Then, the second fuel passage 19 is made conductive. Therefore, the high-pressure liquid-phase fuel that has flowed from the fuel cylinder 15 to the second fuel passage 19 passes through the second gas-phase / liquid-phase operation switching valve 42 and then the flow rate is controlled by the fuel flow rate control valve 43 while the idle port 13 or the second main nozzle 12 is injected into the intake passage 2 and mixed with the intake air passing through the intake passage 2 to generate an air-fuel mixture. Therefore, the gas engine E starts by sucking the air-fuel mixture and warms up. Enter the driving state. At this time, the idle port 13 mainly ejects fuel during idling of the gas engine E, and the second main nozzle 12 mainly ejects fuel during load operation.

  Thus, during operation of the gas engine E with liquid phase fuel, the venturi negative pressure generated in the venturi portion 2a of the intake passage 2 is transmitted to the pressure receiving chamber 72 through the venturi negative pressure transmission passage 74, and the diaphragm 73 is moved to the piston rod. Since the pressure is drawn downward together with 75, the control force for the control piston 64 is added with a venturi negative pressure, in other words, an intake air amount element in addition to the vapor pressure in the fuel cylinder 15. As a result, the amount of liquid fuel ejected from the second main nozzle 12 is controlled to be inversely proportional to the vapor pressure in the fuel cylinder 15 and proportional to the intake air amount, and the air-fuel ratio of the air-fuel mixture generated by the mixer 3 is controlled. Is optimized.

  The first gas phase / liquid phase operation switching valve 22 is heated by the gas engine E in operation with such liquid phase fuel, and the first fuel passage 18 is heated by the muffler 6.

  Thus, since the gas engine E can be started and warmed up by liquid phase fuel, the low temperature region in which the gas engine E can be operated can be greatly expanded.

  When the thermal expansion material 35 of the first gas phase / liquid phase operation switching valve 22 is heated by the gas engine E to a temperature at which the gas fuel can be supplied to the gas engine E, the thermal expansion of the thermal expansion material 35 As a result, the temperature-sensitive piston 32 descends against the urging force of the valve spring 40, and the valve body 39 is opened via the valve rod 36, whereby the first fuel passage 18 is brought into a conducting state.

  Thus, the liquefied fuel in the fuel cylinder 15 passes through the first fuel passage 18 heated by the muffler 6 to become gas phase fuel, and passes through the first gas phase / liquid phase operation switching valve 22. Since the pressure is reduced to a predetermined pressure by the pressure reducing valve 23 and further reduced to substantially the atmospheric pressure by the zero governor 24 to fill the zero governor chamber 25, the gas phase fuel passes from the first main nozzle 11 through the venturi portion 2 a of the intake passage 2. The air is sucked out by the intake air, and is mixed with the intake air and is sucked into the gas engine E.

  Further, as soon as the pressure reducing operation of the pressure reducing valve 23 is started, the outlet pressure is supplied to the first pressure receiving chamber 47 of the second gas phase / liquid phase operation switching valve 42 through the pressure transmission passage 53, The first diaphragm 49 that has received the pressure is displaced against the urging force of the valve opening spring 55 to immediately open the piston valve 54, shut off the second fuel passage 19, and liquid-phase fuel to the intake passage 2. Stop erupting.

  In this way, the gas engine E is smoothly switched from the operation using the liquid phase fuel to the operation using the gas phase fuel, and the original low fuel consumption is ensured.

  Next, a second embodiment of the present invention shown in FIG. 2 will be described.

  In the second embodiment, a first fuel flow rate control valve 43 ′ and a second fuel flow rate control valve 80 are interposed in series in the second fuel passage 19. The first fuel flow control valve 43 'is the same as the fuel flow control valve 43 of the first embodiment except that it does not include the venturi negative pressure control system including the diaphragm 73. It is the same composition as. The second fuel flow control valve 80 includes a second jet 81 in the second fuel passage 19 connecting the main jet 61 and the second main nozzle 12, and a second needle valve that adjusts the opening area of the second jet 81. The throttle valve 5 is connected to the second needle valve 82 via an interlocking mechanism 83 so that the second needle valve 82 operates in the opening direction in response to an increase in the opening of the throttle valve 5. The interlocking mechanism 83 includes a pinion 84 that interlocks with the rotation of the valve shaft of the throttle valve 5, and a rack 85 that is formed on the outer periphery of the second needle valve 82 and is driven by the pinion 84. Since other configurations are the same as those of the first embodiment, portions corresponding to those of the first embodiment are denoted by the same reference numerals in FIG.

  Thus, since the opening of the throttle valve 5 reflects the intake air amount of the gas engine E, according to the third embodiment, as in the first embodiment, when the gas engine E is operated with the liquid phase fuel. The amount of fuel ejected from the second main nozzle 12 is controlled so as to be inversely proportional to the vapor pressure in the fuel cylinder 15 and proportional to the intake air amount. The air-fuel ratio can be optimized.

  Finally, a third embodiment of the present invention shown in FIG. 3 will be described.

  In the third embodiment, instead of the second main nozzle 12 and the idle port 13 in the first embodiment, a fuel injection valve 90 capable of injecting liquid phase fuel into the intake passage 2 downstream from the throttle valve 5 is mixed. 3, an electronic control unit 91 is connected to the fuel injection valve 90. The electronic control unit 91 is supplied with electric power from the alternator 8, and outputs an engine rotation speed sensor 92 for detecting the rotation speed of the gas engine E and an output signal of the throttle sensor 93 for detecting the opening degree of the throttle valve 5. The fuel injection amount of the fuel injection valve 90 is controlled based on the gas engine operation information. Since other configurations are the same as those of the first embodiment, portions corresponding to those of the first embodiment are denoted by the same reference numerals in FIG.

  According to the third embodiment, when the gas engine E is started and operated with liquid phase fuel, the fuel injection amount to the mixer 3 is finely controlled according to the gas engine speed and the throttle opening, Therefore, it is possible to supply an air-fuel mixture having an appropriate air-fuel ratio over a wide operating range from idling to load operation, which can contribute to improvement in output performance and fuel efficiency.

  The present invention is not limited to the above embodiments, and various design changes can be made without departing from the scope of the invention. In the first gas phase / liquid phase operation switching valve 22, a diaphragm can be used instead of the temperature-sensitive piston 32.

E ... Gas engine S ... Fuel supply device 3 ... Mixer 5 ... Throttle valve 10 ... Crank chamber 15 ... Fuel cylinder 18 ... First fuel passage 19 ... Second fuel passage 22 ... First gas phase / liquid phase operation switching valve 23, 24 ... Pressure reducing device (pressure reducing valve, zero governor)
42... Second gas phase / liquid phase operation switching valve 43... Fuel flow control valve 43 ′ Fuel flow control valve (first fuel flow control valve)
80... Second fuel flow control valve (second fuel flow control valve)
90 ... Fuel injection valve 91 ... Electronic control unit

Claims (7)

A fuel cylinder (15) filled with liquefied fuel, a mixer (3) for supplying an air-fuel mixture to the gas engine (E), and a fuel that has been sent from the fuel cylinder (15) into a gas phase is supplied to the mixer (3 ) And a decompression device (23, 24) provided in the first fuel passage (18) for decompressing the fuel in the gas phase. In the device,
A second fuel passage (19) for supplying liquid fuel delivered from the fuel cylinder (15) to the mixer (3) is provided in parallel with the first fuel passage (18);
The first fuel passage (18) is normally closed and is provided with a first gas phase / liquid phase operation switching valve (22) that opens when the gas engine temperature exceeds a predetermined temperature,
The second fuel passage (19) is opened when the gas engine (E) is started and operated, but is closed in conjunction with the opening of the first gas phase / liquid phase operation switching valve (22). A fuel supply device for a gas engine, comprising a two-gas phase / liquid phase operation switching valve (42). The fuel supply device for a gas engine according to claim 1,
The pressure reducing device includes a pressure reducing valve (23) for reducing the gas-phase fuel passing therethrough to a predetermined pressure by opening the first gas phase / liquid phase operation switching valve (22), and the pressure reducing valve (23). A zero governor (24) for reducing the decompressed fuel to approximately atmospheric pressure and supplying it to the mixer (3) is provided. The second gas phase / liquid phase operation switching valve (42) includes the pressure reducing valve (23 The gas engine fuel supply device is configured to be closed by receiving the predetermined pressure of the vapor-phase fuel delivered from the gas generator. The fuel supply device for a gas engine according to claim 1 or 2,
The second gas phase / liquid phase operation switching valve (42) is configured such that when the first gas phase / liquid phase operation switching valve (22) is closed, when the gas engine (E) is started and operated, its crank chamber (10) A fuel supply device for a gas engine, which is configured to open by receiving a negative pressure generated in the gas engine. The fuel supply device for a gas engine according to claim 1,
The second fuel passage (19) has a fuel flow control valve (43, 43 ') for controlling the fuel flow rate in the second fuel passage (19) in inverse proportion to the vapor pressure in the fuel cylinder (15). A fuel supply device for a gas engine, characterized in that The fuel supply device for a gas engine according to claim 4,
The fuel flow control valve (43) is configured to increase the fuel flow rate in the second fuel passage (19) in response to an increase in the venturi negative pressure generated in the venturi section of the mixer (3). A fuel supply device for a gas engine. The fuel supply device for a gas engine according to claim 4,
The second fuel passage (19) has a second fuel flow rate control for controlling the fuel flow rate in the second fuel passage (19) in proportion to the opening of the throttle valve (5) of the mixer (3). A fuel supply device for a gas engine, characterized by comprising a valve (80). The fuel supply device for a gas engine according to claim 1,
A fuel injection valve (90) capable of injecting liquid phase fuel in the second fuel passage (19) when the second gas phase / liquid phase operation switching valve (42) is opened is attached to the mixer (3). The fuel injection valve (90) is connected to an electronic control unit (91) for controlling the fuel injection amount of the fuel injection valve (90) according to the operating state of the gas engine (E). Engine fuel supply system.

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