JP2014070603A - Gas engine and work machine using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas engine capable of improving startability in replacing a gas cylinder or at a low temperature so that an air remaining in a regulator can be automatically discharged by operating a choke mechanism.SOLUTION: A pressing mechanism 90 is disposed to forcibly press a second diaphragm 77 of a regulator 7 from the external in conjunction with a choke lever 60 in operating a choke mechanism by moving a choke plate 61. In operating the choke mechanism, the second diaphragm 77 is pressed with the pressing mechanism 90 to open a needle valve 79, so that communication between the first pressure reducing chamber 75 and a second pressure reducing chamber 75 is established. Thus the remaining air can be excluded from the first and second pressure reducing chambers to effectively supply an evaporated fuel gas to a crank case 4 side even in a cold starting, and startability of an engine can be remarkably improved. A check valve 63 is disposed on the choke plate 61 to prevent leakage of the fuel gas flowing into the diaphragm 7, to the external.

Description

  The present invention relates to a gas engine, and more particularly to a gas engine for a portable working machine used for a brush cutter using a cassette type gas cylinder filled with liquefied fuel, and a gas engine working machine using the same.

  For example, as shown in Patent Document 1, a gas engine using a cassette type gas cylinder filled with liquefied petroleum gas is known. FIG. 14 is a perspective view showing the entire brush cutter 1001 equipped with a two-cycle gas engine that uses liquefied petroleum gas (LPG) or the like filled in a cassette gas cylinder as a fuel. The brush cutter 1001 has a rotary blade 1003 attached to the tip of the operating rod 1002 and a gas engine attached to the rear end of the operating rod 1002. The output of the gas engine is supplied to the rotary blade 1003 via a drive shaft (not shown) inserted through the operation rod 1002. The operator operates the brush cutter 1001 by holding the handle 1004 attached to the operation rod 1002. The cassette type gas cylinder is accommodated in a gas cylinder case 1005. Many of these cassette type gas cylinders generally use liquefied butane.

  11 to 13 show the configuration of a fuel supply unit used in a conventional gas engine. FIG. 11 is a partial cross-sectional view illustrating a structure for taking out fuel from the gas cylinder 20 to the regulator 107 in a conventional gas engine. In FIG. 11, the gas cylinder 20 is set horizontally so that the leading end 23 a of the extraction pipe 23 bent in an L shape provided in the gas cylinder 20 faces downward. In the gas cylinder 20 set in this way, liquid fuel 22 accumulates below due to gravity, and vaporized fuel 21 accumulates at its saturated vapor pressure above. For this reason, the liquid fuel 22 is always supplied from the take-out pipe 23 to the gas engine. When the stem 25 at the tip of the gas cylinder 20 is inserted into the socket 27, it flows to the fuel passage 9 through the check valve 29 and the fuel passage 28 (passages 28 a and 28 b). The fuel passage 9 is a metal conduit that also functions as a vaporizer by being bent around the side of the cylinder 3. In the portion (vaporizer portion 9b) of the fuel passage 9 disposed near the cylinder, the liquid fuel 22 is vaporized in the fuel passage 9 by the heat of the cylinder 3 and the like, and the gaseous gas is sent to a known regulator 107. To do. In the regulator 107, the first pressure reducing chamber 71 and the second pressure reducing chamber 75 are passed through and adjusted to a predetermined gas pressure, and then mixed with the air flowing in from the intake port 85 and supplied to the cylinder through the crankcase. To do.

  FIG. 12 is an enlarged longitudinal sectional view of the regulator 107 of FIG. As shown in FIG. 12, generally, in the first decompression chamber 71 of the regulator 107, the first lever 72, the first diaphragm 73, and the first spring 74 are about 350 mmAq (gauge pressure). The pressure is adjusted to 0035 MPa (gauge pressure). In the second decompression chamber 75, the second lever 76, the needle valve 79, the second diaphragm 77, and the second spring 78 are about 0 mmAq (gauge pressure), and about 0 MPa (gauge pressure) (= atmospheric pressure) in terms of ISO. Pressure is adjusted. A cover 187 having an opening hole is provided in the second decompression chamber. When the pressure in the first decompression chamber 71 becomes higher than about 0.0035 MPa (gauge pressure), the first diaphragm 73 is pushed down against the urging force of the first spring 74 by the gas pressure. Then, the connection side 72b of the first diaphragm 73 of the first lever 72 is lowered, and the passage 81 is closed by swinging around the fulcrum 72c so that the valve portion 72a on the other end side is raised. Conversely, when the pressure in the first decompression chamber 71 becomes lower than about 0.0035 MPa (gauge pressure), the first diaphragm 73 is pushed up by the urging force of the first spring 74, and the first lever 72 is moved in the opposite direction. The valve portion 72a swings around the fulcrum 72c and opens the passage 81 to flow in. When a predetermined pressure is reached, the valve portion 72a closes the passage 81 and maintains a constant pressure.

  The second decompression chamber 75 is operated in the same manner, and when the piston (not shown) rises, the crankcase chamber side below the piston becomes negative pressure, and the piston (not shown) serves as a cylinder air supply port (not shown). When it rises further upward, it is sucked out to the crankcase chamber side, and the pressure in the second decompression chamber 75 communicating with the intake port 85 becomes lower than about 0 MPa (gauge pressure). Then, since the front surface (the side far from the main jet 83) of the second diaphragm 77 is open to the atmospheric pressure, it is pushed forward (to the main jet 83 side) by the differential pressure between the front and rear surfaces of the second diaphragm 77. Since one end side (upper end side) 76 b of the second lever 76 is in contact with the second diaphragm 77, the upper end side 76 b of the second lever 76 is pushed by the second diaphragm 77 against the urging force of the second spring 78. The fulcrum 76c swings (the fulcrum 76c moves clockwise in the figure), and the lower end 76a of the second lever 76 moves to the second diaphragm 77 side. A needle valve 79 is attached to the lower end side 76a of the second lever 76, and the needle valve 79 moves to the second diaphragm 77 side. Then, the passage 82 and the needle valve 79 are gradually opened, and the first decompression chamber 71 and the second decompression chamber 75 communicate with each other through the passage 82. Since the pressure in the first decompression chamber 71 is about 0.0035 MPa (gauge pressure) and the second decompression chamber 75 is a negative pressure, it flows from the first decompression chamber 71 side to the second decompression chamber 75 side, As a result, the air is mixed with the air from the intake port 85 and the air cleaner (not shown) through the main jet 83 and flows into the cylinder 3 through the crankcase. This operation continues while the gas engine is running. When the gas engine is stopped and the piston (not shown) stops, the crankcase under the piston does not become a negative pressure, so suction to the crankcase side is eliminated. Then, the second decompression chamber 75 communicated from the intake port 85 becomes atmospheric pressure, and the second diaphragm 77 returns to the original position. The second lever 76 is also swung so that the upper end side 76b of the second lever 76 moves away from the main jet 83 by the biasing force of the second spring 78, and the lower end side 76a of the second lever 76 moves toward the needle valve 79 side. Moving. As a result, the needle valve 79 also moves forward, returns to the original position, closes the passage 82, and keeps the pressure in the second decompression chamber 75 constant (about 0 MPa (gauge pressure)). At this time, the vaporized fuel flow is completely stopped.

JP-A-7-34980

  By the way, in the gas engine of patent document 1, since the cylinder and the vaporizer part of the vicinity of the cylinder are cold at the time of starting in a low temperature environment around 5 ° C., the vaporization of the liquid fuel supplied from the gas cylinder becomes insufficient. Startability may deteriorate. Further, particularly at the start immediately after the gas cylinder is set for the first time at the beginning of the operation of this type of working machine, the liquid fuel 22 is extruded at a stretch with the saturated vapor pressure of the fuel in the gas cylinder 20 as shown in FIG. The cross-sectional area and volume of the vaporizer portion 9b in the fuel passage 9 are very small, and the temperature of the vaporizer portion 9b is low at the time of startup, so that the liquid fuel 22 flows through the passage in the vaporizer portion 9b. Therefore, as shown in FIG. 13, the air 55 in the original fuel passage 9 before setting the gas cylinder 20 is pushed out to the regulator 107 side by the liquid fuel 22. When the valve portion 72a of the first lever 72 of the regulator 107 becomes about 0.0035 MPa (gauge pressure) or more, the passage 81 is closed, so that the valve portion 72a is immediately closed and flows in from the valve portion 72a of the first lever 72 and the gas cylinder 20 side. The air 55 in the original vaporizer section 9b remains confined while being compressed between the liquid fuel and the liquid level 50 shown in FIG. In the compressed air 55 remaining in the confinement, the fuel gas evaporated from the liquid surface is mixed, and the pressure becomes the same as the saturated vapor pressure of the liquid fuel at this temperature. Since the remaining air 55 that has been trapped is compressed first, the amount of fuel gas is very small. In this state, the first decompression chamber 71 of the regulator 107 is still confined with air in which the fuel gas is dilute, and the second decompression chamber 75 contains only air and has no fuel gas content.

  Even if the starter rope is pulled and the crankshaft is turned to start the gas engine in this state, there is little fuel gas that can be sucked into the crankcase side via the regulator 107 at the beginning, and therefore an ignition explosion occurs in the cylinder. I can't start. By pulling the starter rope further and performing cranking that rotates many crankshafts, the air initially trapped in the regulator 107 and the vaporizer unit 9b can be sucked out and extracted. As a result, it had to be sucked into the cylinder, which sometimes resulted in work involving fatigue. Further, the saturated vapor pressure around 5 ° C. of liquefied butane which is a general fuel is about 0.02 MPa (gauge pressure), and the extrusion pressure from the gas cylinder is low, so that the liquid in the vaporizer portion 9 b of the fuel passage 9 is low. The arrival position (height) of the liquid level 50 of the fuel is shortened, and the location where the fuel component is present is the position far from the regulator 107. That is, the lower the temperature, the more insufficient the fuel supply into the cylinder 3 and the worse the startability.

  The present invention has been made in view of the above problems, and has a good startability and good operability even when a cassette type gas cylinder filled with liquefied fuel is set for the first time at a low temperature or at the beginning of work, and a It aims at providing the used engine working machine.

  Another object of the present invention is to provide a gas engine that can automatically discharge air remaining in a regulator by operating a choke mechanism, and an engine working machine using the same.

  Still another object of the present invention is to provide a gas engine that can be easily improved in startability only by changing a regulator without changing the basic structure on the engine body side or gas cylinder storage chamber side, and an engine working machine using the same. Is to provide.

  A gas engine according to a first aspect of the present invention includes a socket having a fuel flow path that is attached to a detachable gas cylinder filled with a liquefied gas and communicates with the gas cylinder, and a gas from the gas cylinder is supplied to a first decompression chamber and a second decompression chamber. A regulator that regulates pressure through the chamber and mixes with air from the air inlet, and a fuel passage that communicates the regulator and the socket and has a vaporizer section that vaporizes liquid fuel. In a gas engine having a first diaphragm in a connected first decompression chamber and a second diaphragm in a second decompression chamber that communicates with the first decompression chamber and is connected to an intake port, the second diaphragm is pressed to press the second diaphragm. And a pressing means for forcibly communicating the intake port. Further, choke means for closing the intake port at the start of the gas engine is provided, and the pressing means operates in conjunction with operation of the choke means. The choke means has a swingable choke lever having a choke plate for opening and closing the intake port at one end and an operating portion at the other end, and the pressing means puts the second diaphragm into a pressed state when the choke lever is operated. Including a cam mechanism configured to maintain.

  According to another aspect of the present invention, the cam mechanism is configured to convert the rotational motion of the choke lever by a predetermined angle into the linear motion of the pin member that presses the second diaphragm. The cam mechanism has one end facing the shaft core portion of the second diaphragm in the second decompression chamber and the other end having an uneven surface in the axial direction, and a spring-biased pin member movable in the axial direction, and the pin member A drive cam member capable of engaging with or disengaging from the concave and convex surface of the pin and pushing out the pin member in the axial direction, and a lever extending in a radial direction from the drive cam member. The lever of the drive cam member and the choke lever are engaged. The other lever is also operated by operating one lever.

  According to still another feature of the present invention, the cam mechanism is attached to a cover that covers the second decompression chamber of the regulator, and is arranged so that the swing surface of the choke lever and the rotation surface of the lever of the drive cam member are orthogonal to each other. good. A small diameter air hole (through hole) is formed in the choke plate, and a check valve that allows air to flow only in the intake direction is provided in the air hole.

According to the first aspect of the present invention, since the pressing means for pressing the second diaphragm to connect the second decompression chamber and the intake port is provided, even at the start immediately after the gas cylinder is set for the first time at a low temperature or at the beginning of work. By operating the pressing means, the second diaphragm can be pushed to bring the fuel passage from the second decompression chamber to the crankcase into communication, and high-concentration fuel can be sent into the crankcase. In addition, since the vaporized fuel gas is slightly higher than the atmospheric pressure, it is possible to expel the remaining air that is initially trapped in the regulator and vaporizer without cranking, and the fuel gas content can be quickly removed. It can flow into the crankcase. Further, since the fuel continuously flows at this time, the crankcase is in a rich fuel supply state. Therefore, if cranking is performed, the vaporized fuel enters the cylinder from the crankcase, so that it is easy to ignite and explode even during cold start at low temperatures, and the startability of the gas engine can be improved with a simple operation process. .
According to the invention of claim 2, since the pressing means can be operated in conjunction with the operation of the choke means, the residual air in the second decompression chamber can be extracted only by operating the choke lever.
According to the invention of claim 3, since the pressing means includes the cam mechanism that keeps the second diaphragm in the pressing state when the choke lever moves, the choke without the operator being aware of the operation of the pressing means. Just operate the lever.
According to the invention of claim 4, since the cam mechanism converts the rotational movement of the choke lever into the linear movement of the pin member that presses the second diaphragm, it is possible to press the second diaphragm with a simple cam mechanism. Thus, an increase in manufacturing cost for implementing the present invention can be suppressed.
According to the invention of claim 5, the cam mechanism is constituted by a pin member movable in the axial direction, a drive cam member rotatable in the radial direction, and a lever extending in a radial direction from the drive cam member. Therefore, it is possible to realize a mechanism for pressing the second diaphragm with a simple cam mechanism having a small number of components.

According to the invention of claim 6, since the cam mechanism is attached to the cover covering the second decompression chamber of the regulator, the regulator used in the present invention can be easily realized only by changing the cover portion covering the second decompression chamber of the regulator. .
According to the seventh aspect of the present invention, the rocking surface of the choke plate and the rotating surface of the lever of the drive cam member are arranged so as to be orthogonal to each other, so that this arrangement is not affected by the arrangement relationship with other devices of the regulator. The pressing mechanism of the invention can be arranged.
According to the eighth aspect of the present invention, since the choke plate is formed with a small air hole and the air hole is provided with the check valve that allows air to flow only in the intake direction, the second diaphragm is pushed to continuously intake the air passage. Even if vaporized fuel gas with a pressure slightly higher than atmospheric pressure flows into the intake port, the closed part of the choke plate closes the inlet and the air cleaner extends from the air hole to the outside, improving safety. Can do. Further, if cranking is performed thereafter, a small amount of air can be sucked in, so that startability can be improved while improving safety.
According to the ninth aspect of the invention, since the work equipment is driven using the gas engine according to any one of the first to seventh aspects, an engine working machine that is easy to handle and has good startability can be realized.

  The above and other objects and novel features of the present invention will become apparent from the following description and drawings.

It is a gas engine rear view concerning the present invention, and is a figure showing the inside of gas cylinder case 10 with a sectional view. It is a longitudinal cross-sectional view of the regulator 7 in the cross section of the AA part of FIG. FIG. 3 is a front view (partial cross section) of the regulator as viewed from the front side in FIG. 2 (when the lever 95 is not operated). FIG. 4 is a cross-sectional view taken along the line CC of FIG. 3 and is a rear view of the regulator 7. FIG. 3 is a front view (partial cross section) of the regulator as viewed from the front side of FIG. 2 (when the lever 95 is operated). It is a rear view of the regulator 7 seen from the CC cross section of FIG. It is a longitudinal cross-sectional view of the regulator 7 when the lever 95 is pushed down as shown in FIG. It is sectional drawing of the DD section of FIG. FIG. 3 is a side view of a pin member 91 and a drive cam member 94 of FIG. 2. FIG. 3 is a perspective view of a pin member 91 and a drive cam member 94 in FIG. 2. It is a fragmentary sectional view explaining the taking-out structure of the fuel from the gas cylinder 20 in the conventional gas engine to the regulator 107. FIG. 12 is an enlarged vertical sectional view of the regulator 107 in FIG. 11. It is a fragmentary sectional view explaining the taking-out structure of the fuel from the gas cylinder case 10 to the regulator 107 in the conventional gas engine. (Part 2). The perspective view of the brush cutter carrying the gas engine which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same portions are denoted by the same reference numerals, and repeated description is omitted. Further, in the present specification, description will be made assuming that the front and rear directions and the up and down directions are directions shown in the drawing. FIG. 1 is a rear view of a gas engine 1 according to the present invention, and shows a gas cylinder case 10 in a cross-sectional view.

  The gas engine 1 includes a cylinder 3 with an ignition plug 14 attached to the upper part, a crankcase 4 attached to the lower part of the cylinder 3, a muffler 5 attached to an exhaust port (not shown) of the cylinder 3, and a cylinder. 3, a regulator 7 and an air cleaner box 6 attached to an intake port (not shown) side of the gas cylinder 3 via an insulator 8, a gas cylinder case 10 attached to the lower part of the crankcase 4 with a plurality of bolts 13, and a gas cylinder case 10 The regulator 7 includes a fuel passage 9 that forms a fuel supply passage. The gas cylinder case 10 has the same configuration as that of the conventional engine working machine, and the gas container 20 can be a cassette stove fuel container specified in JIS standard S2148, a so-called “household gas cylinder”. In this embodiment, the two-cycle gas engine 1 is screwed to the crankcase 4. The gas cylinder case 10 corresponds to the outer diameter shape of the gas cylinder 20 and is an approximately cylindrical container inside, and an opening 10a for inserting the gas cylinder 20 is formed on the right side. A removable cap 11 is attached to the opening 10a. A spring 12 is provided inside the cap 11 and urges the gas cylinder 20 to be pressed against the socket 27 by the spring 12.

  The fuel passage 9 has one end 9 a connected to the gas cylinder case 10 and the other end 9 c connected to the regulator 7. The fuel passage 9 is, for example, a pipe made of metal such as steel, stainless steel, aluminum alloy or the like, and the pipe is piped so as to be located around the radiating fin of the cylinder 3. The vaporization of the liquefied gas in the pipe line is promoted by heating a part of the gas (vaporizer portion 9b). The length of the vaporizer 9b and how the vaporizer 9b is arranged around the radiation fins can be appropriately set.

  A socket 27 for mounting the gas cylinder 20 is provided at the bottom of the accommodation space of the gas cylinder 20 of the gas cylinder case 10. The socket 27 is an attachment member for connecting and fixing the stem 25 of the gas cylinder 20, for example, and a positioning projection 27a is provided on a part of the ring-shaped seat surface. The positioning protrusion 27a is provided for fitting the gas cylinder 20 in the correct direction by fitting the notch 26a of the flange 26. In order to mount the gas cylinder 20, the notch 26 a of the flange 26 of the gas cylinder 20 is aligned with the positioning protrusion 27 a of the socket 27, and the gas cylinder 20 is mounted to the socket 27. When the gas cylinder 20 is correctly installed, the operator attaches the cap 11. In this embodiment, the opening 10a and the cap 11 of the gas cylinder case 10 are fixed by screws, but may be fixed detachably by a latch or other known fixing methods.

  In the vicinity of the center of the flange 26, a cylindrical recess that abuts the connection pipe 24 from the gas cylinder 20 is formed, a through hole is formed in the center of the recess, a check valve 29 is provided in the through hole, and the connection pipe 24. The check valve 29 is opened by pressing the stem 25 at the tip of the cylinder in the axial direction, and the gas can be released from the gas cylinder 20 to the fuel passage 9. The take-out pipe 23 of the gas cylinder 20 is an L-shaped pipe as shown in the figure, and the direction bent perpendicularly from the axial direction is the same direction as the notch 26 a formed in the flange 26. Accordingly, by mounting the socket 27 having the positioning protrusion 27a, the direction of the L-shaped take-out pipe 23 of the gas cylinder 20 can be set correctly downward, and the liquid fuel 22 is sent out in the liquid state until the remaining amount of fuel is reduced. The The reverse valve 29 to the fuel passage 9 are connected by a passage 28a extending in the left-right direction and a passage 28b extending in the up-down direction. In the present embodiment, the passage 28a is configured integrally with the socket 27, but the configuration of the passage 28 is arbitrary.

  Next, the detailed structure of the regulator 7 is demonstrated using FIGS. FIG. 2 is a vertical cross-sectional view of the regulator 7 in a cross section taken along line AA in FIG. The same components and the same components as those of the regulator 107 of the conventional example described in FIG. The main difference between the regulator 7 of this embodiment and the regulator 107 of the conventional example is that a pressing mechanism 90 is provided on the cover 87 of the second decompression chamber 75 of the regulator 7. The pressing mechanism 90 mainly includes a pin member 91 housed in a cup-shaped cover 98, a drive cam member 94 that engages with the pin member 91, and biases the pin member 91 toward the drive cam member 94. A spring 97 and a lever 95 that rotates the drive cam member 94 are configured. When the pressing mechanism 90 is operated by the lever 95, the pressing mechanism 90 forcibly presses the vicinity of the center of the second diaphragm 77 from the outside of the cover 87 of the second decompression chamber 75 so that the second diaphragm 77 moves to the main jet 83 side. Act on. The lever 95 manufactured integrally with the drive cam member 94 is locked with a choke lever 60 (described later), and the drive cam member 94 rotates in conjunction with the operation of the choke mechanism by operating the choke lever 60. Thus, the pin member 91 is moved in the axial direction (on the main jet 83 side) by the action of the drive cam mechanism.

  FIG. 3 is a front view (partially a cross-sectional view) of the regulator as viewed from the front side of FIG. 2 and shows a state when the lever 95 is not operated. The lever 95 is connected to the drive cam member 94 by integral molding or screwing or the like. The lever 95 extends radially outward from the drive cam member 94, and the outer peripheral end (tip 95 a) is the length of the choke lever 60. It arrange | positions so that the hole part 60a may be penetrated. On the upper end side of the choke lever 60, an operation portion 60b is formed by bending the protruding portion into an L shape. As is well known in an engine working machine, the operator can operate the choke mechanism by pushing down the operation unit 60b with a finger. At this time, since the lever 95 passes through the elongated hole portion 60a of the choke lever 60, the lever 95 also moves in conjunction with the movement of the choke lever 60, and the drive cam member 94 rotates by a predetermined angle.

  FIG. 4 is a cross-sectional view taken along the line CC of FIG. 3 and is a side view of the regulator 7. The air cleaner box 6 is connected to the intake port 85 of the regulator 7, and the choke lever 60 is pivotally supported by the swing shaft 64 inside the air cleaner box 6. An elongated hole portion 60a through which the lever 95 passes is formed on one end side of the choke lever 60, and an operation portion 60b is formed in the vicinity of the elongated hole portion 60a. A choke plate (closing plate) 61 is provided on the other end side of the choke lever 60. The choke plate 61 is large enough to close the intake port 85, and a small through hole (air hole) 62a for sucking a minimum amount of air from the outside is provided at the center. A check valve (described later) that allows air to flow only in the intake direction is provided in the vicinity of the through hole 62a. The structure thereof will be described in detail.

  Next, the state when the choke mechanism operates by operating the choke lever 60 will be described with reference to FIGS. FIG. 5 is a front view of the regulator as viewed from the front side of FIG. 2 and shows a state in which the operation portion 60b of the choke lever 60 is pushed down in the direction of the arrow 57 from the state of FIG. Since the tip of the lever 95 passes through the long hole portion 60a of the choke lever 60, the lever 95 rotates about 70 degrees clockwise in the drawing by pushing down the operation portion 60b in the direction of the arrow 57. As the lever 95 rotates, the drive cam member 94 manufactured integrally with the lever 95 rotates, and the relative positional relationship between the drive cam member 94 and the pin member 91 changes. At this time, since the cam mechanism is provided between the drive cam member 94 and the pin member 91, the pin member 91 moves so as to approach the drive cam member 94. Although not understood in FIG. 5, the pin member 91 is held so as not to rotate in the circumferential direction of the cover 98, and can only move in the axial direction.

  FIG. 6 is a cross-sectional view taken along the line CC of FIG. 5 and is a side view of the regulator 7. When the operation portion 60 b of the choke lever 60 is pushed down in the direction of the arrow 57, the choke lever 60 rotates around the swing shaft 64 and the choke plate 61 closes the intake port 85. At this time, since the tip end portion 95a of the lever 95 passes through the long hole portion 60a of the choke lever 60, the lever 95 also rotates in the direction of the arrow 57 together with the choke lever 60. Here, it can be understood that the swinging surface of the choke lever 60 (choke plate 61) and the rotating surface of the lever 95 connected to the drive cam member 94 are arranged to be orthogonal to each other. This state is a state in which the gas engine 1 is started. When the choke mechanism is operated as shown in FIG. 6, the starter knob 40 is pulled and the crankshaft is rotated to start the gas engine 1. Thus, by arranging the lever 95 that operates the pressing mechanism 90 and the rotation surface of the choke lever 60 to be orthogonal to each other, the two mechanisms can be operated or released by an operation by one operation unit 60b. For this reason, the operator can operate the pressing mechanism 90 without being conscious only by performing exactly the same procedure as before (depressing the choke lever 60 at the time of starting), and high startability can be realized.

  7 is a longitudinal sectional view of the regulator 7 when the state shown in FIGS. 5 and 6, that is, when the operation portion 60 b is pushed down as indicated by an arrow 57 and the choke lever 60 is closed. When the lever 95 is pushed down, the substantially cylindrical drive cam member 94 rotates. Since the drive cam member 94 is held so as not to move in the axial direction (see the arrow in the figure), the pin member 91 that is movable in the axial direction is moved by the action of a cam mechanism (not shown). And move toward the second diaphragm 77 in the axial direction. As a result, the pin member 91 protrudes greatly from the cover 87 to the inside, and presses the vicinity of the center of the second diaphragm 77. This is the same state as the state in which the second decompression chamber 75 becomes negative pressure and the needle valve 79 is opened by the second diaphragm 77.

  FIG. 8 is a cross-sectional view taken along the line DD in FIG. In this embodiment, the rotation surface of the choke lever 60 (or the choke plate 61) and the rotation surface of the lever 95 connected to the pressing mechanism 90 (or the rotation surface of the drive cam member 94) are in a perpendicular relationship. Therefore, the configuration of the air cleaner box 6 side can be realized without changing the configuration except for the configuration of the choke lever 60 portion. As shown in FIG. 8, a circular choke plate (closing plate) 61 that is formed at the tip of the choke lever 60 and can close the inlet 85 a is connected to the inlet 85 a of the air inlet 85 in the air cleaner box 6. An operating portion 60b is connected to the other end, and is supported by a swing shaft 64 near the center. A through hole 61a serving as a small-diameter air hole is formed at the center of the choke plate 61, and a case 62 for fixing the check valve 63 is attached to the outside of the through hole 61a. The case 62 has a sufficient internal space for the butterfly check valve 63 to swing, for example, and is provided with a through hole 62a coaxially with the through hole 61a and having the same diameter as the through hole 61a. The check valve 63 is formed inside the cup-shaped case 62 and inside the choke plate 61. Due to the action of the check valve 63, only air flow in the intake direction (direction of arrow F) is allowed in the through holes 61a and 62a, and backflow of air and fuel gas from the regulator 7 side to the air cleaner box 6 side is prevented. The

  The pin member 91 has a convex portion 91 f to be described later on the outer periphery thereof. The convex portion 91 f engages with a guide groove 98 a extending in the axial direction of the inner periphery of the cover 98, whereby the pin member 91 is circumferential with respect to the cover 98. Is held so as to be movable only in the axial direction. A spring 97 is interposed between the inner wall of the cover 98 and the pin member 91 to urge the pin member 91 in the axial direction toward the drive cam member 94. The tip 91e of the pin member 91 is inserted into a hole formed in the center of the cover 87, and when the pin member 91 moves in the axial direction as shown in FIG. (Center part) 77a is arranged to be pressed.

  Next, the shapes of the pin member 91 and the drive cam member 94 will be described with reference to FIGS. 9 and 10. FIG. 9A is a side view of the pin member 91 in the regulator 7 of this embodiment, and FIG. 9B is a side view of the drive cam member 94. The pressing mechanism 90 in the present embodiment includes a pin member 91 that is not rotatable in the circumferential direction and is movable only in the axial direction, and a through hole 94d that penetrates the pin shaft 91d of the pin member 91 and is rotatable in the circumferential direction. A drive cam member 94 that cannot move in the axial direction is included. The pin member 91 has an uneven surface portion in the axial direction from the reference surface 91g and on the drive cam member 94 side. The uneven surface portion is formed with two claw mountain portions 91a and claw valley portions 91b in the circumferential direction. The portion from the claw mountain portion 91a to the claw valley portion 91b is smoothly connected by the inclined portion 91c. Near the central axis of the pin member 91, a cylindrical pin shaft 91d that extends greatly toward the drive cam member 94 is formed. The pin shaft 91d is inserted into a through hole formed at the center of the cover 87 that covers the second decompression chamber 75, and has a shape that allows the shaft core portion 77a of the second diaphragm 77 to be pressed by the tip portion 91e. Is done.

  The drive cam member 94 has a through hole 94d into which the pin shaft 91d is fitted and inserted into the shaft center. Around the through hole 94d, a claw peak portion 94b, an inclined portion 94c, a claw valley, A portion 94a is formed. A lever 95 (see FIG. 8) extends on the outer peripheral surface of the drive cam member 94. In this embodiment, the drive cam member 94 and the lever 95 are manufactured by integral molding of metal or synthetic resin, screwing, or the like. Is done. The drive cam member 94 is rotatable around the pin shaft 91d, and is turned to a position where the claw peak portion 94b and the claw valley portion 94a mesh with the claw peak portion 91a and the claw valley portion 91b of the pin member 91. , Or at a position where the engagement is disengaged. When the meshing state is released, the pin member 91 and the drive cam member 94 are separated (separated) in the axial direction. The pin member 91 is constantly urged toward the drive cam member 94 by a spring 97. By rotating the drive cam member 94, the pin member 91 resists the urging force of the spring 97 by the action of the inclined portions 91c and 94c. 91 moves to the axial spring 97 side. When the drive cam member 94 is rotated from the state where the pin member 91 and the drive cam member 94 are separated, the pin member 91 moves to the drive cam member 94 side by the biasing force of the spring 97. This axial movement is performed by rotating the drive cam member 94 while the inclined portion 91c and the inclined portion 94c are in contact with each other. Thus, by rotating the drive cam member 94 by a predetermined angle in the circumferential direction, the pin member 91 can be moved in the axial direction. When the pin member 91 approaches the drive cam member 94, the pin shaft 91d The tip 91e travels from the through hole of the cover 87 to the second diaphragm 77 side, and the shaft core 77a of the second diaphragm 77 can be pressed.

  According to the gas engine 1 configured as described above, initially, as shown in FIGS. 2 to 4, the positions of the lever 95 of the regulator 7 and the operation portion 60 b of the choke lever 60 are in the upper position. That is, as shown in FIG. 10A, the pin member 91 is a position where the claw crest 94b of the drive cam member 94 and the claw crest 91a of the pin member 91 are in contact with each other, and from the end surface 94e of the drive cam member 94. The protrusion of the pin shaft 91 d is small, and the tip end portion 91 e of the pin member 91 remains at a position where it does not contact the shaft core portion 77 a of the second diaphragm 77. In this state, the second diaphragm 77 is in a normal free position balanced with the atmospheric pressure of the outside air. Further, the inlet of the intake port 85 in the air cleaner box 6 is in a normal open state.

  Before the gas cylinder 20 is set for the first time, the passages 28a and 28b and the fuel passage 9 and the first decompression chamber 71 and the second decompression chamber 75 of the regulator 7 are filled with air as in the state shown in FIG. Yes. At the time of starting in a low temperature environment around 5 ° C., immediately after the gas cylinder 20 is set for the first time at the beginning of the work, the vaporizer section 9b is also cooled and has a small passage cross-sectional area, so as in the conventional example shown in FIG. The liquid fuel 22 in the gas cylinder 20 is extruded at a time with the saturated vapor pressure (approximately 0.02 MPa (gauge pressure) at that time, and from the vaporizer portion 9b of the fuel passage 9 through the passages 28a and 28b while pushing in the air before setting. As a result, the valve portion 72a of the first lever 72 also closes the passage 81 when the pressure becomes equal to or greater than about 0.0035 MPa (gauge pressure) in the regulator 7. The air 5 in the original vaporizer section 9b between the valve section 72a and the liquid level 50 of the liquid fuel 22 flowing in from the gas cylinder 20 side. 11 remains compressed and remains as shown in Fig. 11. A small amount of fuel gas evaporated from the liquid surface is mixed in the remaining air 55, which is the same as the saturated vapor pressure of the liquid fuel at this temperature. Since the remaining air 55 that has been confined is compressed first, the amount of fuel gas is very small, and in the first decompression chamber 71 of the regulator 7, air that is further diluted with fuel gas is confined.

  When the engine is started in this state after setting the gas cylinder 20 as described above, the lever 95 is pushed down as shown in FIG. 5 to FIG. The tip of the lower part also moves together. Then, the contact between the claw peak portions 91a and 94b is released by the turning of the drive cam member 94, and as shown in FIG. 10B, the claw peak portion 91a and the claw valley portion 94a, and the claw valley portion 91b and the claw peak portion 91 94b meshes neatly. Since the pin member 91 is biased by the spring 97, the pin member 91 moves toward the second diaphragm 77 in the axial direction, and the shaft core portion 77a of the second diaphragm 77 is pushed in by the tip end portion 91e. At the same time, the choke plate 61 of the choke lever 60 closes the inlet 85 a of the air inlet 85 in the air cleaner box 6. Since the second diaphragm 77 is pushed, the fuel passage to the crankcase is in communication. Since the vaporized fuel gas is a little higher than the atmospheric pressure, the remaining air that is initially trapped in the regulator 7 and the vaporizer unit 9b is expelled into the crankcase without cranking, and the amount of fuel gas is reduced. It flows into the crankcase 4. Since the fuel gas flows continuously, the crankcase 4 is in a state where a thick fuel is supplied. Further, since the check valve 63 that flows only in the intake direction is provided in the vicinity of the through hole 61a of the choke plate 61 of the choke lever 60, even if vaporized fuel gas having a pressure slightly higher than the atmospheric pressure flows into the intake port 85, The choke plate 61 of the choke lever 60 is not closed and leaks to the outside through the air cleaner box 6.

  If cranking is performed, the vaporized fuel enters the cylinder 3 from the crankcase 4. Since the fuel is butane or the like, the fuel is surely vaporized even when the fuel is excessively concentrated, so there is no problem because the ignition plug electrode does not get wet like gasoline and does not cause poor ignition. Therefore, it is easy to ignite and explode even at a cold start at a low temperature, and the startability of the gas engine 1 can be improved. When the gas engine 1 is started, as shown in FIGS. 2 to 4, the operation unit 60 b is returned to the upper position of the normal position. According to the present embodiment, the pressing mechanism 90 can be operated in conjunction with the same simple operation process as in the prior art in which only the choke lever is operated, and the startability can be greatly improved.

  As mentioned above, although this invention was demonstrated based on the Example, this invention is not limited to the above-mentioned Example, A various change is possible within the range which does not deviate from the meaning. For example, the gas engine according to the present invention can be applied to a chain saw, a hedge trimmer, and the like in addition to the brush cutter 1001. Further, the claw crests for moving the pin member 91 in the axial direction are provided on both the pin member 91 and the drive cam member 94. Although it was provided around the entire circumference, a linear arrangement may be used. Further, the lever 95 is operated in conjunction with the choke lever 60 side, but the choke lever 60 with the lever 95 as the driving side may be moved in conjunction therewith.

DESCRIPTION OF SYMBOLS 1 Gas engine 2 Upper cover 3 Cylinder 4 Crankcase 5 Muffler 6 Air cleaner box 7 Regulator 8 Insulator 9 Fuel passage 9a End part 9b Vaporizer part 9c End part 10 Gas cylinder case 10a Opening part 11 Cap 12 Spring 13 Bolt 14 Ignition plug 20 Gas cylinder 21 Vaporized fuel 22 Liquid fuel 23 Extraction pipe 23a Tip 24 Connection pipe 25 Stem 26 Flange 26a Notch 27 Socket
27a Protrusion 28 Fuel passage 28a, 28b Passage 29 Check valve 40 Starter knob 50 Liquid level 55 Air 60 Choke lever 60a Long hole portion 60b Operation portion 61 Choke plate 61a Through hole 62 Case 62a Through hole 63 Check valve 64 Oscillating shaft 71 First decompression chamber 72 First lever 72a Valve portion 72b Connection side 72c Support point 74 First spring 73 First diaphragm 75 Second decompression chamber 76 Second lever 76a Lower end side 76b Upper end side 76c Support point 77 Second diaphragm 77a Shaft core 78 Second spring 79 Needle valve 81, 82 Passage 83 Main jet 85 Inlet 85a (Inlet) Inlet 87 Cover 90 Press mechanism 91 Pin member 91a Nail crest 91b Nail valley 91c Inclined 91d Pin shaft 91e Tip 91f Convex 94 Drive cam member 94a Claw valley portion 94b Claw mountain portion 94c Inclined part 94d Through hole 94e End face 95 Lever 95a Tip part 97 Spring 98 Cover 98a Guide groove 107 Regulator 1001 Brush cutter 1002 Operating rod 1003 Rotary blade 1004 Handle 1005 Gas cylinder case

Claims (9)

A socket having a fuel flow path to which a detachable gas cylinder filled with liquefied gas is attached and communicated with the gas cylinder;
A regulator that regulates the gas from the gas cylinder through the first decompression chamber and the second decompression chamber and mixes it with the air from the intake port;
A fuel passage that communicates the regulator and the socket and has a vaporizer section that vaporizes the liquid fuel;
A gas engine having a first diaphragm in the first decompression chamber connected to the vaporizer section and a second diaphragm in the second decompression chamber connected to the intake port in communication with the first decompression chamber in the regulator. In
A gas engine comprising a pressing means for pressing the second diaphragm to connect the second decompression chamber and the intake port. Providing a choke means for closing the intake port when the gas engine is started;
2. The gas engine according to claim 1, wherein the pressing unit causes the second decompression chamber and the intake port to communicate with each other when the choke unit is operated. The choke means has a swingable choke lever having a choke plate that opens and closes the intake port at one end and an operating portion at the other end,
The gas engine according to claim 2, wherein the pressing means includes a cam mechanism that keeps the second diaphragm in a pressed state when the choke lever moves.   The gas engine according to claim 3, wherein the cam mechanism converts the rotational movement of the choke lever into a linear movement of a pin member that presses the second diaphragm. The cam mechanism is
A pin member having one end facing the shaft core portion of the second diaphragm in the second decompression chamber, the other end having an uneven surface in the axial direction, and being spring-biased so as to be movable in the axial direction;
A driving cam member that engages or disengages with the uneven surface of the pin member and can push the pin member in an axial direction;
A lever extending radially from the drive cam member;
The gas engine according to claim 4, wherein the lever of the drive cam member and the choke lever are locked, and the other lever is also operated by operating one of the levers.   The gas engine according to claim 5, wherein the cam mechanism is attached to a cover that covers a second decompression chamber of the regulator.   The gas engine according to claim 5 or 6, wherein the swinging surface of the choke lever and the rotating surface of the lever of the drive cam member are arranged to be orthogonal to each other.   The gas engine according to any one of claims 1 to 7, wherein a small air hole is formed in the choke plate, and a check valve that allows air to flow only in an intake direction is provided in the air hole. . A work machine is driven using the gas engine according to any one of claims 1 to 8. A gas engine working machine characterized by things.

Images