JP2013204533A - Engine working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine working machine which is improved in usability by installing both an auto choke mechanism and a manual choke mechanism.SOLUTION: An engine working machine includes a carburetor 35 and an air cleaner box (60), and as a choke means, a manual choke valve 62 that manually narrows an intake passage, and an auto choke valve 65 that is electrically driven by a rotary solenoid 67. The choke means is configured to operate such that either of the choke valves narrows the intake passage of the carburetor 35. The auto choke valve is a plate-like member which turns about a rotary driving shaft 66, and is configured to close all or part of the intake passage by driving the rotary solenoid 67.

Description

  The present invention relates to an engine working machine such as a chain saw or a brush cutter, and more particularly to an engine working machine capable of preventing malfunctions in addition to automation of choke operation.

  In small working machines such as brush cutters and chain saws, small engines are widely used as power sources. FIG. 12 is an external view of a brush cutter as an example of a conventional engine working machine 1001. As shown in FIG. 12, an engine work machine 1001 equipped with a small two-cycle engine passes a drive shaft (not shown) through a pipe-shaped main pipe 1004, and this drive shaft is provided at one end of the main pipe 1004. , The rotary blade 1012 provided at the other end of the main pipe 1004 is rotated. In the vicinity of the rotary blade 1012, a scattering protection cover 1013 for preventing scattering of the grass that has been cut off is provided. The engine work machine 1001 is carried by a shoulder strap (not shown) or the like, and a handle 1008 having a substantially U-shape in front view for operation by an operator is attached to the vicinity of the central portion of the main pipe 1004. The number of revolutions of the engine 1010 is controlled by an operator by a throttle lever 1007 attached to the grip unit 1009. The operation of the throttle lever 1007 is transmitted to the carburetor of the engine 1010 through the wire 1045.

  The engine 1010 used in the engine working machine 1001 is a general-purpose engine that is small and light and can obtain a large output, and can be operated for a long time by replenishing fuel. Manual starters are widely used to start the engine 1010, and various ideas have been proposed to facilitate starting. For example, Patent Document 1 proposes an engine work machine in which a battery and a cell motor are built in and startability is improved by the cell motor.

Japanese Patent No. 3400191

  In the engine working machine of Patent Document 1, the engine can be started using a cell motor, but the choke operation at that time has to be performed manually, and the operation of the choke has been a burden for the operator.

  The present invention has been made in view of the above background, and an object of the present invention is to provide an engine work machine that realizes an auto choke mechanism and improves usability in an engine start operation having a choke mechanism.

  Another object of the present invention is to provide an engine working machine that can prevent malfunctioning of operation while operating a choke, in addition to automation of choke operation.

  Still another object of the present invention is to provide an engine working machine having both an auto choke mechanism and a manual choke mechanism.

  The characteristics of representative ones of the inventions disclosed in the present application will be described as follows.

According to one aspect of the present invention, a carburetor for supplying a fuel / air mixture into the cylinder;
An engine working machine that operates a work device by an engine having a choke means provided on a suction side of a carburetor, the choke means being driven by a first choke valve that manually throttles an intake passage and an electric drive means. And a second choke valve for restricting the intake passage, and when the choke means is operated, either the first or the second choke valve is used to restrict or close the intake passage. An air cleaner chamber (air cleaner box) is provided on the suction side of the vaporizer, and the choke means is provided inside the air cleaner chamber. A rotary solenoid is used as the electric drive means, and the second choke valve is a plate-like member that rotates around the drive shaft of the rotary solenoid. By driving the rotary solenoid, the second choke valve passes through the intake passage. Fully closed or half open. The half-open state mentioned here does not mean that the cross-sectional area of the flow path is narrow, that is, the opposite portion, but refers to a wide opening state that is larger than the fully closed and less than the fully opened. The rotary solenoid is provided outside the air cleaner chamber, and is provided so that its drive shaft extends into the air cleaner chamber. Control means for controlling the driving of the rotary solenoid using the power of the battery is provided.

  According to another aspect of the present invention, the first and second choke valves are plate-like members that are pivotally supported so as to rotate in the same plane as the opening of the intake passage in the air cleaner. An operation lever for operating the choke valve is provided outside the air cleaner chamber. Detection means for detecting that the first choke valve is in an open position that does not restrict the intake passage is provided, and driving of the electric drive means is performed only when the detection means detects that the first choke valve is in the open position. Allow. The detection means is a switch means having a movable piece, and the output of the switch means changes when a part of the moving first choke valve moves the movable piece. Temperature measuring means for measuring the engine or the temperature around the engine is provided, and the control means sets the opening of the second choke valve based on the measured temperature.

According to the first aspect of the present invention, there is provided an engine working machine equipped with both an auto choke valve and a manual choke valve since the intake passage is throttled by the first or second choke valve when the choke means is operated. it can. For this reason, even if the battery for operating the auto choke valve runs out, the engine can be started well using the manual choke valve.
According to the invention of claim 2, since the auto choke valve operates only when it is detected by the detecting means that the first choke valve is in the open position, the auto choke valve operates during the operation of the manual choke valve. Can be prevented.
According to the invention of claim 3, since the detecting means is a switch means having a movable piece, it is possible to realize a detecting means for detecting the operating state of the first choke valve using inexpensive parts.
According to the invention of claim 4, since the choke means is provided in the air cleaner chamber, it is not necessary to change the configuration on the carburetor side, and the choke mechanism of the present invention can be realized only by changing the configuration on the air cleaner chamber side.
According to the invention of claim 5, since the first and second choke valves are plate-like members that are pivotally supported so as to rotate in the same plane as the opening of the intake passage in the air cleaner, In addition, the choke mechanism can be realized with a simple configuration. In addition, since an operation lever for operating the first choke valve is provided outside the air cleaner chamber, a manual choke means with good operability can be realized.
According to the invention of claim 6, the second choke valve is a flat plate member that rotates about the drive shaft by the rotary solenoid, and rotates so as to cover the whole or part of the intake passage (opening thereof). Therefore, an auto choke mechanism can be realized by providing electric drive means having a simple configuration.
According to the seventh aspect of the present invention, since the rotary solenoid is provided outside the air cleaner chamber and its drive shaft extends into the air cleaner chamber, the rotary solenoid can be prevented from being contaminated by the air flowing in the air cleaner chamber. Moreover, since it is not accommodated in the air cleaner chamber, it is possible to prevent the volume of the air cleaner chamber from being reduced, and to prevent adverse effects on the effect of reducing the suction sound.
According to the eighth aspect of the present invention, since the control means for controlling the driving of the rotary solenoid is provided, not only simple opening / closing control for opening or closing the intake passage, but also 1/4 closing of the opening area of the intake passage, High-precision control in multiple stages such as 1/2 closing and 3/4 closing can be performed.
According to the invention of claim 9, since the control means sets the opening of the second choke valve based on the measured temperature, it is possible to set the operation of the efficient choke valve based on the engine temperature. it can.

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

It is a longitudinal section showing the internal structure of engine working machine 1 concerning the example of the present invention. It is a rear view of the engine working machine 1 which concerns on the Example of this invention. It is sectional drawing of the AA part of FIG. It is a perspective view which shows the structure of the carburetor 35 and the air cleaner base member 60 of the engine which concerns on the Example of this invention. FIG. 5 is a side view of the air cleaner base member 60 portion of FIG. 4 and shows a state in which an intake passage 39 is closed by an auto choke valve 65. It is a rear view of the carburetor 35 and the air cleaner base member 60 of the engine which concerns on the Example of this invention. It is a bottom view of the carburetor 35 and the air cleaner base member 60 of the engine which concerns on the Example of this invention. FIG. 5 is a side view of the air cleaner base member 60 portion of FIG. 4 and shows a state during normal operation of the engine 10. FIG. 5 is a side view of the air cleaner base member 60 portion of FIG. 4, showing a state in which an intake passage 39 is closed by a manual choke valve 62. It is a block diagram which shows the whole structure containing the control circuit 70 which concerns on the Example of this invention. It is a flowchart which shows the starting procedure of the engine working machine 1 which concerns on the Example of this invention. It is a perspective view which shows an example (brusher) of the conventional engine working machine 1001. FIG.

  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 this specification, description will be made assuming that the front, rear, left, right, and up and down directions are directions shown in the drawing.

  FIG. 1 is a longitudinal sectional view showing the internal structure of the engine working machine 1 according to this embodiment. The engine 10 is a two-cycle small engine, the crankshaft 13 is disposed coaxially with the main pipe 1004 (see FIG. 12), and the cylinder 11 is disposed so as to extend substantially upward in the vertical direction from the crankcase 14, The piston 12 reciprocates in the cylinder 11 in the vertical direction. The high-voltage current generated by the ignition coil 23 is transmitted to the spark plug 25 through the ignition cord 24 and the plug cap 25a. A fuel tank 27 is provided below the crankcase 14 of the engine 10. The fuel tank 27 contains a mixed oil of gasoline and oil for two cycles and is sent to a vaporizer described later.

  One end of a drive shaft (not shown) is connected to the front side (output side) of the crankshaft 13 via a clutch shaft 32 via a centrifugal clutch 29. An engine cooling fan is integrally formed with the magnet rotor 22 to which the centrifugal clutch 29 is attached. The centrifugal clutch 29 is a known centrifugal clutch in which the oscillator 30a is connected to the clutch drum 30b by centrifugal force when the rotation speed of the crankshaft 13 becomes equal to or higher than a certain value. The clutch shaft 32 is rotatably held by a bearing 33 held by a housing 34.

  A decompressor 31 is provided at a position adjacent to the combustion chamber of the cylinder 11 (a side surface of the cylinder 11 in FIG. 1). The decompression 31 is a decompression mechanism, and is a mechanism for releasing part of the pressure in the combustion chamber when the engine 10 is started to facilitate the compression work by the piston 12 and making the engine 10 easier to start. In this embodiment, the decompression 31 is provided with a decompression button 31a which is an operation button, and a part of the pressure in the cylinder 11 is released by pushing the decompression button 31a (moving the decompression button 31a from the rear to the front side). be able to. When the first combustion (first explosion) immediately after the rotation of the crankshaft 13 occurs, the decompression 31 automatically returns due to the pressure fluctuation.

  As a starting device of the present embodiment, a manual recoil starter 40 is provided on the rear end side of the crankshaft 13. The recoil starter 40 is rotated at a high speed by pulling a starter rope 42 wound around a reel 41 with a starter handle, which will be described later, and the one-way clutch 46 protrudes radially outward by centrifugal force and comes into close contact with the drum 47. Rotate. Since the drum 47 is fixed to the crankshaft 13, when the drum 47 rotates, the crankshaft 13 also rotates and the engine can be started. The released starter rope 42 is wound around the reel 41 by the restoring force of the spiral spring 43. When starting the engine 10, the power switch (not shown) is turned on, and then the engine 10 is started using the recoil starter 40. When stopping the engine 10 during operation, the engine 10 is stopped by switching the power switch from “ON (operation)” to “OFF (stop)”.

  FIG. 2 is a rear view of the engine working machine 1 according to the embodiment of the present invention. A carburetor 35 is provided on the left side of the engine 10 via an insulator 19 that connects an intake port of the engine 10, and a storage space for an air cleaner that filters inhaled air is formed on the outside (left side) of the carburetor 35. An air cleaner cover 61 is provided. A muffler 16 is provided on the side (right side) of the engine 10, and an exhaust port 16 a serving as an exhaust gas outlet is provided on the rear surface side of the muffler 16. The muffler 16 is covered with a resin muffler cover 8 to prevent the operator from touching it directly. The upper part of the engine 10 is covered with a cylinder cover 7. A recoil starter 40 (see FIG. 1) is provided coaxially with the crankshaft 13 and at the rear end thereof, and the recoil starter 40 is covered with a starter case 9. A starter handle 36 is provided on the left side of the starter case 9. A fuel tank 27 is provided below the crankcase 14. The fuel tank 27 is a container formed of a translucent polymer resin, and a mixed fuel in which gasoline and a predetermined ratio of oil are mixed can be put in by removing the cap 28 attached to the opening. A decompression button 31 a is arranged above the starter case 9 so as to be exposed to the outside from a part of the cylinder cover 7. When starting the engine 10, first, the power switch is turned on, and the engine is started by pushing the decompression button 31a and then pulling the starter handle.

  FIG. 3 is a vertical cross-sectional view of the AA portion of FIG. 1 in a plane perpendicular to the crankshaft 13 of the engine working machine 1. The engine 10 is a two-cycle single-cylinder engine that includes a crankcase 14 and a cylinder 11 that extends substantially vertically above the crankcase 14. Since the engine intake-compression-explosion-exhaust stroke is the same as that of a known two-cycle engine, a detailed description thereof will be omitted. In the present embodiment, the cylinder 11 is formed by integrally casting a cylinder main body, a head portion, and a heat dissipating fin, for example, with an aluminum alloy, and a spark plug 25 is attached to the upper portion of the cylinder 11.

  The cylinder cover 7 is a cover made of synthetic resin such as plastic, for example, and mainly covers the cylinder 11 that becomes hot during operation so that an operator cannot directly touch them. The cylinder 11 is provided with a carburetor 35 via an insulator 19. A fuel pipe 50 for supplying fuel from the fuel tank 27 is connected to the inlet of the carburetor 35 to be described later. A filter 51 is provided at one end of the fuel pipe 50, and the other end is connected to an inlet (not shown) of the carburetor 35 through the through hole 27 b of the fuel tank 27. A filter 51 is provided at the tip of the fuel pipe 50. A return pipe 54 is connected to a surplus fuel discharge port (not shown) of the carburetor 35, and an end of the return pipe 54 opens into the fuel tank 27 through the through hole 27 c. Rubber bushes 52 and 53 for preventing fuel leakage are provided in the through holes 27b and 27c.

  The carburetor 35 is provided with a priming pump 37 for sucking the mixed fuel from the fuel tank 27 to the carburetor 35. The priming pump 37 is a hemispherical transparent valve, and the operator sucks the fuel into the carburetor 35 by repeatedly pushing the priming pump 37 until the fuel flows through the return pipe 54 immediately before the engine 10 is started. The operator can visually confirm that the fuel has reached the vaporizer 35 when the mixed fuel has reached the transparent valve portion of the priming pump 37.

  An air cleaner base member 60 that forms an air cleaner chamber is attached to the suction side (left side) of the vaporizer 35, and an opening of the air cleaner base member 60 is covered with an air cleaner cover 61. An air filter (not shown) is provided in the air cleaner chamber. A muffler 16 is provided on the opposite side of the cylinder 11 from the vaporizer 35. A catalyst (not shown) is preferably provided in the muffler 16 for purification of exhaust gas. The muffler 16 is directly fixed to the cylinder 11 by two muffler fastening bolts 17 (only one is visible in the figure).

  Next, a specific configuration and operation of the choke mechanism (choke means) according to the present embodiment will be described with reference to FIGS. It is a perspective view which shows the structure of the carburetor 35 and the air cleaner base member 60 of the engine which concerns on the Example of this invention. In the present embodiment, an air cleaner box is provided on the suction side of the carburetor 35 attached to the cylinder 11 via an insulator 19 (see FIG. 3). The air cleaner box includes an air cleaner base member 60 and an air cleaner cover 61 (see FIG. 3) covering the air cleaner base member 60, and FIG. 4 shows a state in which the air cleaner cover 61 and the air cleaner element are removed. The air cleaner base member 60 is fixed to the vaporizer 35 and is a container having a predetermined volume with one surface opened. In the present embodiment, the choke means according to the present invention is disposed inside the air cleaner base member 60. The choke means is mainly composed of two choke valves, one is a manual choke valve (first choke valve) 62 for manual operation by an operator, and the other is movable by electric drive means. An auto choke valve (second choke valve) 65 is provided. The choke means is a member for adjusting the air-fuel ratio of the air-fuel mixture burned in the cylinder to temporarily increase, and the intake negative pressure from the combustion chamber is reduced by opening and closing the intake passage opening with a choke valve. Increase the fuel mixing ratio to facilitate engine start, especially cold start. In this embodiment, the manual choke valve 62 and the auto choke valve 65 are constituted by a thin metal plate or an integrally molded member made of synthetic resin. Further, on one surface of the manual choke valve 62 and the auto choke valve 65, an elastic body such as rubber (not shown) is attached to a position where the air cleaner base member 60 comes into contact with the opening of the intake passage 39 to seal the air. May be increased. Both the manual choke valve 62 and the auto choke valve 65 are pivotally supported in the vicinity of one end portion, and the vicinity of the tip end on the other end side that rotates is formed in a flat plate shape suitable for covering the circular opening of the intake passage 39. . If the manual choke valve 62 and the auto choke valve 65 have a shape that can effectively close or throttle the intake passage from the suction inlet of the atmosphere to the fuel supply port of the carburetor, where is the arrangement position? The configuration of the overall shape is arbitrary.

  The manual choke valve 62 can be swung by an operation lever 64 and is fixed to the rotating shaft by a screw 63 provided coaxially with the rotating shaft. A rotation shaft (not shown) penetrates from the through hole (not shown) of the air cleaner base member 60 to the outside on the vaporizer 35 side and is connected to the operation lever 64. The auto choke valve 65 is a choke valve that can be rotated by a rotary solenoid 67 provided on the carburetor 35 side of the air cleaner base member 60, and is fixed to a rotary drive shaft 66 of the rotary solenoid 67. The rotary solenoid 67 is a known electric drive that uses a cylindrical permanent magnet for the rotor to rotate by repulsion and attraction between the permanent magnet of the rotor and the magnetic pole generated at the yoke, and to rotate the rotating shaft instantaneously by a certain angle. Means. The rotary solenoid 67 is driven by electric power supplied from a battery 71 (not shown). When the energization is cut off, the rotary shaft is moved to the initial position (by the force of the return spring disposed in the rotary solenoid 67). It returns to the position of FIG. Although there is no problem in performance even if the rotary solenoid 67 without the return spring is used, there is an advantage that consumption of the battery 71 can be suppressed if the specification with the return spring is used.

  In FIG. 5, the manual choke valve 62 is in an open position (a position where the intake passage 39 is not closed by the choke valve), and a switch 69 (choke state detection unit) that operates when the manual choke valve 62 is in the open position is provided in the air cleaner base member 60. It is provided in a part of the inner wall. The switch 69 is a push button switch that switches an electric circuit connected to the switch 69 to an on or off state when a movable piece 69a such as a plunger moves, and when the manual choke valve 62 is at the illustrated position, A part of the abutting portions 62b pushes the movable piece 69a (moves backward), whereby the switch 69 is turned on. In this embodiment, the output of the switch 69 is transmitted to the control means for controlling the operation of the auto choke valve 65, and the auto choke valve 65 is configured to be operable when the switch 69 is in the on state.

  On the other hand, in FIG. 5, the auto choke valve 65 is in a closed position (a position where the intake passage 39 is closed by the choke valve). This state can be positioned by energizing the rotary solenoid 67 from the control means (control circuit 70). At this time, the longitudinal center line of the auto choke valve 65 (a one-dot chain line connecting the rotation drive shaft 66 and the choke hole 65a) 83 is a longitudinal center line of the manual choke valve 62 (a point connecting the choke hole 62a from the screw 63). The positional relationship is almost perpendicular to the chain line 81.

  FIG. 6 is a rear view of the carburetor 35 and the air cleaner base member 60 of the engine according to the embodiment of the present invention. A priming pump 37 is provided below the carburetor 35, and a discharge port 38b to which a return pipe 54 for returning excess fuel to the fuel tank is connected is provided in the vicinity of the priming pump 37. The operating lever 64 is an operating means for operating the manual choke valve 62, and a rotating shaft 68 (not shown) provided in a through hole (not shown) of the air cleaner base member 60 is provided on the upper portion thereof.

  FIG. 7 is a bottom view of the carburetor 35 and the air cleaner base member 60 of the engine according to the embodiment of the present invention. The carburetor 35 of the present embodiment has the same structure as a known carburetor used in an engine working machine of a conventional example. The carburetor 35 is connected to the fuel pipe 50 at the position of the priming pump 37 and the discharge port 38b. These arrangements are the same as in the conventional example. However, the shape of the air cleaner box attached to the carburetor 35, that is, the shape of the air cleaner base member 60, the choke mechanism attached to the air cleaner base member 60, and the driving means of the choke mechanism are different. A rotary solenoid 67 is provided on the side (vaporizer side) of the air cleaner base member 60, and an operation lever 64 of the manual choke valve 62 is disposed on the side away from the rotary solenoid 67. The operation lever 64 is connected to the rotating shaft 68 of the manual choke valve 62. Although not shown in FIG. 7, two power lines (not shown) are connected to the rotary solenoid 67 and a direct current for driving the rotary solenoid 67 is supplied. Electric power for driving the rotary solenoid 67 is controlled by a control circuit 70 (not shown).

FIG. 8 is a side view of the air cleaner base member 60 portion. In the state of FIG. 4, the intake passage 39 is fully open, and shows a state when the engine is operating after starting. Both the manual choke valve 62 and the auto choke valve 65 are in a normal position (a state where the choke mechanism is not operated). In the normal position, the manual choke valve 62 turns on the switch 69 when the contact portion 62b pushes (moves backward) the movable piece 69a of the contact portion 62b. Manual choke valve 62 the rotation shaft a pivotable about a (screw 63 coaxial) by rocking angle theta _1, the longitudinal centerline of the manual choke valve 62 in the normal position becomes the position of the dashed line 81, The center line in the longitudinal direction of the manual choke valve 62 at the choke position is the position of the alternate long and short dash line 82. This operation can be operated by the operator moving the operation lever 64 by θ _{1 in the} direction of the arrow.

On the other hand, the auto choke valve 65 can be rotated about the rotation drive shaft 66 by the swing angle θ ₂ . The auto choke valve 65 can be rotated about the rotation drive shaft 66 by a swing angle θ ₂ , and the longitudinal center line of the auto choke valve 65 at the normal position is a position indicated by a one-dot chain line 84. The center line in the longitudinal direction of the valve 65 is the position of the alternate long and short dash line 83. When the auto choke valve 65 is in the normal position, a part of the abutment portion 65 b abuts against the inner wall of the air cleaner base member 60, thereby serving as a stopper for the rotation position of the auto choke valve 65.

  FIG. 9 is a side view of the air cleaner base member 60 and shows a state where the intake passage 39 is closed by the manual choke valve 62 (a state at the choke position). The manual choke valve 62 can be set at the choke position by moving an operation lever 64 provided outside the air cleaner base member 60 in the direction of the arrow 85. At this time, since the contact portion 62b of the manual choke valve 62 is separated from the movable piece 69a of the switch 69, the movable piece 69a is released by the repulsive force of a spring (not shown), and the switch 69 is turned off. The control means 70 detects from the output of the switch 69 that the manual choke valve 62 is operating, and at this time, power is not supplied to the rotary solenoid 67. This configuration may be configured such that the drive current is not supplied to the rotary solenoid 67 by, for example, short-circuiting the wiring for supplying power to the rotary solenoid 67 when the switch 69 is turned off. With this configuration, the auto choke valve 65 does not act when the manual choke valve 62 is not in the normal position, so that malfunction can be prevented.

  FIG. 10 is a block diagram showing the overall configuration including the control circuit 70 according to the embodiment of the present invention. The control circuit 70 is driven by using the battery 71 as a power source, and can be configured using, for example, a microcomputer. The control circuit 70 controls the rotation of the engine 10 using the outputs of the rotation speed detection unit 74 and the temperature detection unit 73 and also controls the auto choke mechanism of this embodiment. The control means 70 controls the rotary solenoid 67 according to the output of the choke state detection unit (switch) 69, and the state of the manual choke valve 62 by the choke state display means 72 attached at a position where it can be seen by the operator. Configured to display. As the choke state display means 72, for example, an LED is desirably used, and it may be provided on a flange portion near the main body, a side surface of the air cleaner base member 60, or the like, which is a position where visual observation is easy when using the recoil starter. According to this, the operator can appropriately grasp which of the manual and automatic choke valves is in operation, and can prevent forgetting to release the choke valve. The control circuit 70 performs control so that the operation of the auto choke valve 65 is canceled when the driving of the engine 10 is detected. The determination as to whether or not the engine 10 has been driven is made based on the rotational speed detected by the rotational speed detection unit 74. The rotational speed detection unit 74 has, for example, a Hall IC attached to the housing on the side surface of the magnet rotor. Configured.

  Next, the operation procedure of the auto choke mechanism of the engine work machine 1 according to the embodiment of the present invention will be described using the flowchart of FIG. First, when a power switch (not shown) is turned on before starting the engine, a control circuit 70 (not shown) is activated (step 101). Next, the operator operates the priming pump 37 to suck the fuel into the vaporizer 35 and operates the manual choke valve 62 by operating the operation lever 64 as necessary, or uses the auto choke valve 65. Therefore, the manual choke valve 62 is not operated. Next, the control circuit 70 detects whether or not the manual choke valve 62 has been operated by the operator based on the output of the signal from the switch 69 (step 102). Here, when the operator operates the manual choke valve 62, it is not necessary to operate the auto choke valve 65, so the routine proceeds to step 107. On the other hand, when the operator does not operate the manual choke valve 62, the control circuit 70 measures the temperature of the engine by the temperature detector 73 (step 103). The temperature measured here may be, for example, a temperature detected by a temperature sensor provided near the cylinder of the engine, but the auto choke valve 65 is operated after measuring and considering not only the temperature of the engine but also the atmospheric temperature. May be determined.

  Next, it is determined whether or not the auto choke valve 65 needs to be operated based on the measured temperature (step 104). For example, when the atmospheric temperature is higher than 40 degrees, or when it has not been time since the engine was stopped, it is not necessary to operate the auto choke valve 65, so the operation flow of the auto choke mechanism is skipped. , Go to Step 107. Next, the control circuit 70 sets the opening of the auto choke valve 65, that is, the choke opening, and operates the auto choke valve 65 (steps 105 and 106). The choke opening may be set according to the engine temperature and / or the outside air temperature. For example, when the engine is cold and the outside air temperature is less than 10 degrees, the entire opening area of the intake passage 39 is automatically choked. When the valve 65 is closed and the angle is 10 degrees or more and less than 20 degrees, 1/4 of the opening area is closed (fully closed state). A half-open state may be set such that the opening area is ½ closed when the angle is 20 degrees or more and less than 30 degrees, and the opening area is 3/4 closed when the angle is 30 degrees or more and less than 40 degrees. Note that the relationship between the temperature range and the degree of opening is not limited to the above example, and optimal conditions may be set according to the type of engine, fuel, oil, and the like.

  Next, the control circuit 70 determines whether or not the engine has started depending on whether the engine 10 continues to rotate (step 107). If not, the operation of steps 102 to 106 is repeated (step 107). . When starting at step 107, if the auto choke valve 65 is operating, the control circuit 70 releases the operation and returns to the normal position shown in FIG. 8 (step 108). When the auto choke valve 65 is not operated, the operator releases the manual choke valve 62 by operating the operation lever 64, and the control of the flowchart shown in FIG.

  As described above, in this embodiment, since the operation of the choke means is automated, the operator can easily perform the operation at the time of starting, and an easy-to-use engine work machine with improved startability can be realized. Further, since the auto choke valve 65 driven by the rotary solenoid 67 operated by the control circuit 70 is made variable in the region where the intake passage 39 is closed in accordance with the fluctuation of the environmental temperature, an optimum choke valve suitable for the environmental temperature is provided. Operation can be realized. Furthermore, in the present invention, since the engine is started using the auto choke means, the startability can be dramatically improved in a general-purpose engine used for an engine working machine. Further, even when the remaining amount of the battery 71 is not present, the startability equivalent to that of a conventional general-purpose engine can be secured by using a manual choke valve.

  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, although a rotary type carburetor is used for the general-purpose engine used in the engine working machine described above, the present invention can be similarly applied to a cubic type carburetor and other types of carburetors. In the above-described embodiments, the brush cutter is used as an example of the engine working machine. However, not only the brush cutter, but also other engine work that operates the work equipment using a general-purpose engine such as a cutter, a chain saw, or a lawn mower. The same applies to the machine.

1 Engine work machine 7 Cylinder cover
8 Muffler cover 9 Starter case 10 Engine 11 Cylinder 12 Piston 13 Crankshaft 14 Crankcase 16 Muffler 16a Exhaust port 17 Bolt 19 Insulator 22 Magnet rotor 23 Ignition coil 24 Ignition cord 25 Spark plug 25a Plug cap 27 Fuel tank 27b, 27c Through hole 28 Cap 29 Centrifugal clutch 30a Oscillator 30b Clutch drum 31 Decompression 31a Decompression button 32 Clutch shaft 33 Bearing 34 Housing 35 Vaporizer 36 Starter handle 37 Priming pump 38a Inlet 38b Discharge port 39 Intake passage 40 Recoil starter 41 Reel 42 Starter rope 43 spiral spring 46 one-way clutch
47 Drum 50 Fuel pipe 51 Filter 52 Rubber bush 54 Return pipe 60 Air cleaner base member 61 Air cleaner cover 62 Manual choke valve 62a Choke hole 62b Abutting part 63 Screw 64 Operation lever 65 Auto choke valve 65a Choke hole 65b Abutting part 66 Rotation drive Shaft 67 Rotary solenoid 68 Rotating shaft 69 Switch 69a Movable piece 70 Control circuit (control means) 71 Battery 72 Choke state display means 73 Temperature detection part 74 Rotation speed detection part 1001 Engine work machine 1004 Main pipe 1007 Throttle lever 1008 Handle 1009 Grip part 1010 Engine 1012 Rotary blade 1013 Spattering protection cover 1045 Wire

Claims (9)

A carburetor for supplying a mixture of fuel and air into the cylinder via an intake passage;
An engine working machine for operating a working device by an engine having a choke means provided on the suction side of the vaporizer,
The choke means has a first choke valve that manually varies the opening degree of the intake passage, and a second choke valve that is driven by electric drive means and makes the opening degree of the intake passage variable. ,
When the choke means is operated, the engine working machine is characterized in that the intake passage is fully closed or half-opened by the first or second choke valve. Detecting means for detecting that the first choke valve is in an open position not restricting the intake passage;
2. The engine working machine according to claim 1, wherein driving of the electric drive unit is permitted when the detection unit detects that the first choke valve is in an open position. The detection means is a switch means having a movable piece,
3. The engine working machine according to claim 2, wherein an output of the switch unit is changed by a part of the moving first choke valve moving the movable piece. 4. An air cleaner chamber is provided on the suction side of the vaporizer,
The engine working machine according to any one of claims 1 to 3, wherein the choke means is provided in the air cleaner chamber. The first and second choke valves are flat members that are pivotally supported so as to rotate in the same plane as the opening of the intake passage in the air cleaner,
The engine working machine according to claim 4, wherein an operation lever for operating the first choke valve is provided outside the air cleaner chamber. Using a rotary solenoid as the electric drive means,
The second choke valve is a flat plate member that rotates around a drive shaft by the rotary solenoid,
6. The engine working machine according to claim 1, wherein the second choke valve causes the intake passage to be fully closed or half-opened by driving the rotary solenoid.   6. The engine working machine according to claim 5, wherein the rotary solenoid is provided outside the air cleaner chamber, and is provided so that a drive shaft thereof extends into the air cleaner chamber.   The engine working machine according to any one of claims 1 to 6, further comprising a control unit that controls driving of the electric driving unit using electric power of a battery. Providing a temperature measuring means for measuring the temperature of the engine or the surroundings of the engine;
9. The engine working machine according to claim 8, wherein the control means sets the opening of the second choke valve based on the measured temperature.

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