JP4970297B2 - Vaporizer control device - Google Patents

Description

  The present invention mainly relates to a control device for a carburetor of a general-purpose engine, and in particular, is connected to a throttle lever that opens and closes a throttle valve, opens the throttle valve when the engine is stopped, and depends on the rotational speed when the engine is operated. A governor device that opens and closes the throttle valve, a choke return spring that urges the choke lever that opens and closes the choke valve in the closing direction of the choke valve, and the choke lever that is connected to open the choke valve as the engine temperature rises The present invention relates to an improvement in a control device for a carburetor comprising an auto choke device, wherein a choke lever is connected to an outer end portion of a valve shaft of the choke valve that protrudes above the carburetor body.

Such a throttle valve control device for a carburetor is already known as disclosed in, for example, Patent Document 1.
JP 2006-242143 A

  In the conventional carburetor control device, when the engine is idling, the choke valve is controlled to be fully closed by the auto choke device. Generally, the carburetor is provided with a relief mechanism that opens the choke valve in response to the intake negative pressure on the downstream side of the choke valve rising above a predetermined value. However, in the relief mechanism, it is desirable to set the relief spring set load as small as possible in order to facilitate the opening of the choke valve due to negative intake air pressure in order to prevent excessive fuel injection during cold idling of the engine. However, since the intake negative pressure pulsation is relatively intense when the engine is idling, the choke valve opening becomes unstable due to the intake negative pressure pulsation if the set load is sufficiently reduced. Under these circumstances, the set load of the relief spring cannot be set sufficiently small, and there is room for improvement in fuel efficiency of the engine.

  The present invention has been made in view of such circumstances, and in the cold idling state of the engine, the choke valve is mechanically set to a predetermined intermediate opening degree in conjunction with the closing of the throttle valve to the idle opening degree. An object of the present invention is to provide a control device for a carburetor that can be opened to ensure a stable idling state with low fuel consumption.

In order to achieve the above object, the present invention is connected to a throttle lever that opens and closes a throttle valve, opens the throttle valve when the engine is stopped, and opens and closes the throttle valve according to the rotational speed when the engine is operated. A governor device, a choke return spring that urges a choke lever that opens and closes the choke valve in the closing direction of the choke valve, and an auto choke device that is connected to the choke lever and opens the choke valve in response to an increase in engine temperature. In the carburetor control device, the choke lever is connected to the outer end of the choke valve valve shaft protruding above the carburetor body, and the throttle lever is controlled by the governor device when the engine is cold. The choke lever is moved to the intermediate position of the choke valve in conjunction with the rotation to the idling position or its vicinity. Configure the throttle lever to pivot to the location, and the choke lever, between the carburetor body top surface, color interposed fitted rotatably to the valve shaft of the choke valve to be choked lever in a rotationally The choke return spring is composed of a torsion coil spring whose both ends are locked to the choke lever and the vaporizer main body upper surface, and the coil portion is concentrically surrounded by the outer peripheral surface of the collar. a feature that.

According to the onset bright, after the cold start of the engine, by operation of the governor device, when the throttle lever is rotated in the idle opening position or its vicinity of the throttle valve, the choke lever in conjunction with this choke Since the valve will rotate to the intermediate opening position of the valve, the intermediate opening position of the choke valve is stabilized without being affected by the pulsation of the intake negative pressure, and the fuel injection amount from the fuel nozzle is stably optimized. Therefore, a stable cold idling state can be secured with low fuel consumption of the engine.

Moreover, between the choke lever and the upper surface of the carburetor main body , a collar as an intermediate member that is rotatably fitted to the valve shaft of the choke valve so as to be rotatable relative to the choke lever is interposed. Because it is separated from the upper surface of the vaporizer main body, even when it is cold, rainwater and washing water adhering to the upper surface of the vaporizer main body freezes, and the collar as the intermediate member should be fixed to the vaporizer main body. The rotation of the choke lever is not hindered. Therefore, the choke lever can be reliably rotated against the urging force of the choke return spring by the throttle lever, and the choke valve can be opened to an intermediate opening . In addition, the collar as the intermediate member is supported between the carburetor body and the choke lever just by fitting it to the outer circumference of the valve shaft of the choke valve. Therefore, the valve shaft of the choke valve is used for the support. No special support member is required.

  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.

  1 is a front view of a part of a general-purpose engine according to the present invention, FIG. 2 is an enlarged view of a main part of FIG. 1, FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 4 is a sectional view taken along the line 5-5 in FIG. 2, FIG. 6 is a sectional view taken along the line 6-6 in FIG. 2, and FIG. 7 is an operation explanatory view of the auto choke device corresponding to FIG. Is another explanatory diagram of the operation of the auto choke device, FIG. 9 is a further explanatory diagram of the operation of the auto choke device, FIG. 10 is an enlarged view of the temperature sensing portion in the auto choke device in FIG. 6, and FIG. 12 is a schematic side view of the governor device, FIG. 13 is an enlarged sectional view taken along line 13-13 of FIG. 4, FIG. 14 is a sectional view taken along line 14-14 of FIG. 13, and FIG. FIG.

  First, in FIGS. 1-3, the code | symbol E shows the 4-cycle engine used as the motive power source of various working machines. The engine E includes a crankcase 2 that supports a crankshaft 1 that is disposed in a vertical direction, a cylinder block 3 that has a cylinder bore 3 a that protrudes horizontally from the crankcase 2, and an outer end portion of the cylinder block 3. The cylinder head 4 includes an intake port 6i and an exhaust port 6e that are opened and closed by an intake valve 7i and an exhaust valve 7e, respectively, and an intake valve 7i and an exhaust valve 7e. A valve operating chamber 9 that houses the valve operating mechanism 8 that operates is provided. A head cover 5 that closes the valve operating chamber 9 is joined to the end face of the cylinder head 4.

  The outer ends of the intake port 6i and the exhaust port 6e are opened on one side surface and the other side surface of the cylinder head 4 facing in opposite directions, respectively, and the carburetor body Ca of the carburetor C is formed in a plate shape on the one side surface. They are joined by a plurality of through bolts 12 with the heat insulating member 10 interposed therebetween. The carburetor main body Ca includes an intake passage 11 connected to the intake port 6 i of the cylinder head 4. The heat insulating member 10 is made of a thermosetting synthetic resin such as phenol resin having excellent heat insulating properties, and thereby heat conduction from the engine E to the vaporizer C is suppressed. An exhaust muffler 14 that communicates with the exhaust port 6 e is attached to the other side of the cylinder head 4. In addition, a fuel tank 17 and a recoil starter 15 are disposed above the engine E. In FIG. 1, reference numeral 16 denotes a spark plug screwed to the cylinder head 4.

  As shown in FIGS. 2 and 4, an air cleaner 13 connected to the upstream side of the intake passage 11 is attached to the carburetor C.

  The carburetor C has a butterfly choke valve 19 that opens and closes the upstream portion of the intake passage 11, a butterfly throttle valve 20 that opens and closes the downstream side thereof, and an opening between the valves 19 and 20. A fuel nozzle (not shown) is provided, and both the valve shafts 19a, 20a of the choke valve 19 and the throttle valve 20 are rotatably supported in a vertical posture on the carburetor body Ca.

  As shown in FIGS. 4 and 13 to 15, the valve shaft 19 a of the choke valve 19 is arranged offset to one side from the center line of the intake passage 11, and the choke valve 19 is choked in its fully closed state. The side of the valve 19 having a large radius is inclined with respect to the center line of the intake passage 11 so as to come to the downstream side of the intake passage 11 from the side having a small radius. A choke lever 22 is attached to the outer end of the valve shaft 19a protruding above the vaporizer body Ca. The choke lever 22 includes a bottomed cylindrical hub 22a that is rotatably fitted to the valve shaft 19a, and a lever arm 22b that protrudes integrally on one side of the hub 22a. Between the lower end surface of 22a and the upper surface of the vaporizer body Ca, the collar 61 is rotatably fitted to the outer peripheral surface of the valve shaft 19a so as to be able to rotate relative to the hub 22a. Inside the hub 22a, a pair of stopper projections 62 and 62 'are formed in the circumferential direction with a certain interval, and a relief lever 63 that can be rotated only between the stopper projections 62 and 62' is formed. A relief spring 64 is provided between the hub 22 a and the relief lever 63 so as to be fixed to the valve shaft 19 a and urged so that the relief lever 63 abuts against one stopper projection 62 located on the closed side of the choke valve 19. The relief lever 63 and the relief spring 64 constitute a relief mechanism 60.

  A pair of stopper walls 65 and 65 'are formed on the outer periphery of the lower portion of the hub 22a at intervals in the circumferential direction. A stopper pin 66 disposed between the stopper walls 65 and 65' is a vaporizer body Ca. Projected on the outer surface.

And Thus, by one of the stopper wall 65 abuts against the stopper pin 66, is defined a closed position C of the choke valve 19, by the other stopper wall 65 'abuts against the stopper pin 66, the choke valve 19 An opening position O is defined. The choke lever 22 is urged toward the closed position C by the urging force of the choke return spring 21. The choke return spring 21 is composed of a torsion coil spring, and the coil portion 21a is disposed so as to concentrically surround the collar 61, and its one end portion 21b protrudes from the upper surface of the vaporizer body Ca. The other end portion 21c is locked to the stopper wall 65 of the hub 22a to the locking pin 68 provided.

  When the intake negative pressure of the engine exceeds a certain value when the choke valve 19 is fully closed or when the opening is small, the rotational moment due to the intake negative pressure acting on the larger radius side of the choke valve 19 and the radius of the choke valve 19 are smaller. The difference from the rotational moment due to the intake negative pressure acting on the side overcomes the rotational moment due to the relief spring 64 and increases the opening degree of the choke valve 19. It is regulated by contacting '.

  Connected to the lever arm 22b of the choke lever 22 is an auto choke device A that automatically controls the opening of the choke valve 19 according to the temperature change of the engine E. The auto choke device A will be described with reference to FIGS.

  First, in FIGS. 2 to 6, the auto choke device A is connected to a temperature sensing portion 25 that receives heat from the cylinder head 4 of the engine E, particularly around the intake port 6i, and between the temperature sensing portion 25 and the lever arm 22b. The heat receiving operation of the temperature sensing unit 25 is composed of an output unit 26 that transmits the choke lever 22 as movement in the opening direction of the choke valve 19. The temperature sensing portion 25 is a cylindrical shape that is disposed in a storage chamber 27 formed in the cylinder head 4 by a peripheral wall 4a of the intake port 6i and a surrounding wall 4b (see FIGS. 2 and 3) that stands from the upper portion of the peripheral wall 4a. The housing 30 is provided. Similarly to the intake port 6 i, the storage chamber 27 opens at one side of the cylinder head 4 with one end as an inlet, and the opposite end toward the center of the cylinder head 4 is closed. In addition, one side of the accommodation chamber 27 is appropriately opened in consideration of the moldability of the surrounding wall 4b and the assembling property of the temperature sensing portion 25.

The housing 30 is made of a metal having an excellent thermal conductivity, for example, made of Al and having a cup-shaped first portion 30a having a bottom portion 30a ', and a synthetic resin having an excellent heat insulating property, for example, a phenol resin, and the first portion 30a is opened. It comprises a cylindrical second portion 30b that is fitted with a seal stamp at the end and joined by a screw 46 (see FIG. 2). The second portion 30b is integrally connected to the heat insulating member 10 interposed between the cylinder head 4 and the vaporizer C. Therefore, the housing 30 is attached to the cylinder head 4 without providing a dedicated attachment member. Will be.

  The first portion 30 a has its bottom 30 a ′ facing the back side of the storage chamber 27, that is, the central portion (high temperature portion) of the cylinder head 4, and its bottom 30 a ′ and peripheral wall are in contact with the inner surface of the storage chamber 27 or a minute gap is formed. And arranged so as to face each other. The second portion 30 b is disposed on the inlet side of the storage chamber 27, that is, on the side away from the center of the cylinder head 4.

  As shown in FIG. 10, the temperature sensing unit 25 is made of a metal such as Al having excellent thermal conductivity and has a bottomed movable cylinder 31, and a guide member 32 that is caulked and coupled to the open end of the movable cylinder 31. The guide member 32 is slidably supported. The rod-like fixed piston 33 penetrating the guide member 32 and the fixed piston 33 in the movable cylinder 31 are covered with the open end between the movable cylinder 31 and the guide member 32. An elastic bag 34 sandwiched between the two and a wax 35 sealed in the movable cylinder 31 so as to cover the elastic bag 34, and the outer end of the fixed piston 33 is the bottom of the first portion 30 a of the housing 30. The movable cylinder 31 is slidably fitted into the first portion 30a of the housing 30 while being in contact with the inner surface of 30a ′.

  Thus, the wax 35 expands when heated and compresses the elastic bag 34 so as to squeeze the elastic bag 34, thereby pushing the fixed piston 33 outward of the guide member 32. Since the fixed piston 33 whose outer end is in contact with the inner surface of 30a 'is immovable, the reaction of the movable piston 31 causes the movable cylinder 31 to move in the first portion 30a in the direction of arrow F (see FIG. 11) away from the bottom 30a'. Will move forward.

  The outer peripheral surface of the movable cylinder 31 has a small diameter on the opposite side to the guide member 32, a distance collar 36 is fitted to the small diameter portion 31a, a retainer 37 that contacts the distance collar 36, and a heat insulating member. 10, a coiled return spring 38 that biases the movable cylinder 31 toward the outer end side of the fixed piston 33 via the distance collar 36 is contracted. Therefore, the retainer 37 is sandwiched between the distance collar 36 and the return spring 38.

As shown in FIGS. 5 and 6, the output portion 26 includes rods 43 that penetrate the heat insulating member 10 and connect one end portion 43 a to the retainer 37, and both sides of the bracket 10 a that is integrally formed with the heat insulating member 10. The first and second levers 41 and 42 are supported by a common pivot 40 on the surface and can be individually rotated, and the other end 43b of the rod 43 bent in an L shape is provided on the first lever 41. The first lever 41 is rotated in the direction of the arrow R in FIG. 6 by the axial movement of the rod 43 that is connected and moves forward F of the movable cylinder 31. The rod 43 is connected to the retainer 37 by sandwiching the enormous end portion 43 a at one end of the rod 43 between the retainer 37 and the end surface of the movable cylinder 31.

  The first and second levers 41 and 42 have contact portions 41a and 42a that come into contact with each other so as to be separated along the rotational direction of the both, and the first lever 41 has the contact portions 41a and 42a. When rotating relative to the second lever 42 in the direction of arrow R, they are separated from each other. The first and second levers 41 and 42 are provided with spring engaging portions 41b and 42b, and both levers 41 and 42 are brought into contact with the contact portions 41a and 42a. Both ends of the connecting spring 44 urging in the contact direction are locked.

  The second lever 42 is integrally formed with an operating arm 42c operatively opposed to a driven pin 22c provided on the lever arm 22b. When the second lever 42 rotates in the direction of arrow R, the operating arm 42c is formed. However, the choke lever 22 is rotated in the opening direction of the choke valve 19.

  In FIG. 12, a governor device G that automatically controls the opening and closing of the throttle valve 20 will be described. A throttle lever 23 is fixed to the outer end portion of the valve shaft 20a of the throttle valve 20, and a long arm portion 52a of a governor lever 52 fixed to the outer end of the rotary support shaft 51 supported by the engine E is attached to the throttle lever 23. Are connected via a link 53. An output control lever 56 that is supported by the engine E or the like and can rotate in a range from the idling position to the full load position is connected to the governor lever 52 via a governor spring 54. The governor spring 54 normally biases the throttle valve 20 in the opening direction, and the spring load is obtained by rotating the output control lever 56 from the idling position to the full load position or in the opposite direction. Increase or decrease is set.

  Further, an output shaft 55a of a known centrifugal governor 55 driven by the crankshaft 1 of the engine E is connected to the short arm portion 52b of the governor lever 52, and the centrifugal governor 55 that increases with an increase in the rotational speed of the engine E is connected. The output acts on the short arm portion 52b in the closing direction of the throttle valve 20.

  Therefore, when the engine E is stopped, the throttle lever 23 is held at the fully open position of the throttle valve 20 by the set load of the governor spring 54. During the operation of the engine E, the governor lever 52 is output by the output of the centrifugal governor 55. The opening degree of the throttle valve 20 is automatically controlled by the balance between the moment and the moment of the governor lever 52 due to the set load of the governor spring 54.

  4 and 7, the throttle lever 23 is integrally formed with a drive arm 24 that protrudes toward the choke lever 22 side. The drive arm 24 drives the lever arm 22b of the choke lever 22 so that the choke valve 19 is opened from the fully closed position to a predetermined intermediate opening degree when the throttle valve 20 is closed to an idle opening or a vicinity thereof. In addition, the engagement surface 24a of the drive arm 24 with the lever arm 22b is formed in an arc shape centering on the valve shaft 20a of the throttle valve 20, and the throttle valve 20 has an idle opening or When the lever arm 22b is closed in its vicinity, the tip of the lever arm 22b is pressed against the engagement surface 24a in the direction toward the valve shaft 20a of the throttle valve 20 by the urging force of the choke return spring 21.

  Next, the operation of this embodiment will be described.

  In the cold and stopped state of the engine E, as shown in FIG. 10, the wax 35 of the temperature sensing unit 25 is in a contracted state, so that the movable cylinder 31 is moved to the first portion of the housing 30 by the elastic force of the return spring 38. It is held in a retracted position close to the bottom 30a 'of 30a. Accordingly, as shown in FIG. 6, the operating arm 42 c of the second lever 42 of the output unit 26 is held at a position away from the lever arm 22 b of the choke lever 22. The choke valve 19 is held in the closed position by the urging force 21.

  On the other hand, the throttle valve 20 is held in a fully opened state by the governor spring 54 due to the inoperative state of the centrifugal governor 55 (see FIGS. 4 and 6). At this time, when the output control lever 56 is set to the idling position, the load of the governor spring 54 is set to the minimum.

  Therefore, if the recoil starter 15 is operated to start the engine E and the crankshaft 1 is cranked, a large negative pressure is generated in the intake passage 11 downstream of the choke valve 19 in the carburetor C, Since a relatively large amount of fuel is ejected from the fuel nozzle opening at that location and the air-fuel mixture generated in the intake passage 11 is enriched, the engine E can be started smoothly.

  When the engine E is started, the centrifugal governor 55 generates an output corresponding to the rotational speed of the crankshaft 1, and the governor lever 52 is in a direction in which the moment of the governor lever 52 by this output and the moment of the governor lever 52 by the spring force of the governor spring 54 are balanced. As shown in FIG. 7, the throttle valve 20 is closed to the idle opening by the throttle lever 23. In the closing process of the throttle valve 20, the drive arm 24 integrated with the throttle lever 23 is choked. The lever arm 22 b of the lever 22 is rotated in the opening direction of the choke valve 19 against the urging force of the choke return spring 21. Thus, when the choke valve 19 is opened at a predetermined intermediate opening (for example, 30 °), the tip end of the lever arm 22b comes into contact with the arcuate engagement surface 24a of the drive arm 24. As a result, the air amount necessary for idling the engine E can be smoothly taken into the intake passage 11 without depending on the operation of the relief mechanism 60, and the fluctuation of the choke valve 19 due to the pulsation of the intake negative pressure of the engine can be prevented. This prevents the fuel from being ejected excessively from the fuel nozzle and stabilizes the fuel ejection. Therefore, the air-fuel ratio supplied to the engine is adjusted to an appropriate air-fuel ratio corresponding to the cold idling state. As a result, the fuel efficiency of the engine E can be improved.

  Moreover, in this state, the lever arm 22b is pressed against the engagement surface 24a of the drive arm 24 by the repulsive force of the choke return spring 21, and the fluctuation of the throttle lever 23 is also suppressed by the frictional force generated therebetween. Therefore, a more stable cold idling state of the engine can be obtained.

  In particular, the engagement surface 24 a is formed of an arc surface centered on the valve shaft 20 a of the throttle valve 20 as described above, and the tip end portion of the lever arm 22 b has the urging force of the choke return spring 21 to form the engagement surface. Since the pressure contact is made in the direction toward the valve shaft 20a of the throttle valve 20 with respect to 24a, the wobbling of the throttle lever 23 can be effectively suppressed by the frictional force generated in the pressure contact portion, and the throttle lever Even if the valve 23 slightly rotates in the vicinity of the idling opening of the throttle valve 20, the choke valve 19 can be maintained at the intermediate opening.

  By the way, in cold weather, rain water and washing water collected on the upper surface of the vaporizer body Ca may freeze, and in this case, if the lower surface of the choke lever 22 is in direct contact with the upper surface of the vaporizer body Ca, the choke lever 22 Is fixed to the carburetor main body Ca by the icing, and the rotation of the choke lever 22 by the drive arm 24 of the throttle lever 23 is obstructed, but between the hub 22a of the choke lever 22 and the upper surface of the carburetor main body Ca. Since the collar 61 that can rotate relative to the hub 22a is interposed to prevent the choke lever 22 from coming into direct contact with the vaporizer body Ca, rainwater and washing water adhering to the upper surface of the vaporizer body Ca are frozen. Even so, the collar 61 is only fixed and the fixing of the choke lever 22 can be avoided. Therefore, after the engine E is started, the choke lever 22 is reliably rotated against the urging force of the choke return spring 21 by the drive arm 24 in the process of closing the throttle valve 20 to the idle opening by the throttle lever 23. The choke valve 19 can be opened to a predetermined intermediate opening. Moreover, the collar 61 is supported between the carburetor body Ca and the choke lever 22 just by fitting it to the outer periphery of the valve shaft 19a of the choke valve 19, so that the valve shaft 19a of the choke valve 19 is supported by the collar 61. Used, no special support member is required.

Next, when the output control lever 56 is rotated from the idling position to an appropriate load position in order to apply a working machine or other load to the engine E, the load of the governor spring 54 increases accordingly, and this governor spring 54 is increased. The opening of the throttle valve 20 increases when the load of the engine and the output of the centrifugal governor 55 are balanced. When the opening degree of the throttle valve 20 increases beyond the idle opening degree, the drive arm 24 of the throttle lever 23 is released from the pressing force from the lever arm 22b of the choke lever 22, but the engine speed increases and becomes stable. As a result, the operation of the centrifugal governor 55 is stabilized, and the throttle lever 23 does not fluctuate.

  The intake negative pressure generated downstream of the intake passage 11 is also stabilized by the increase in the intake air amount accompanying the increase in the opening degree of the throttle valve 20, and when the intake negative pressure exceeds a predetermined value, the rotation radius of the choke valve 19 is increased. The difference between the rotational moment due to the intake negative pressure acting on the larger side of the choke valve 19 and the rotational moment due to the intake negative pressure acting on the smaller radius side of the choke valve 19 balances the rotational moment due to the relief spring 64 in the choke lever 22. In the meantime, since the choke valve 19 is opened, excessive fuel ejection from the fuel nozzle is suppressed to prevent over-concentration of the air-fuel mixture generated in the intake passage 11 and to ensure a good warm-up operation state. At this stage, since the intake negative pressure is relatively stabilized as the intake amount increases as described above, the choke valve 19 may be staggered even if the choke valve 19 is not forcibly opened by the drive arm 24 of the throttle lever 23. There is no.

  When the temperature of the cylinder head 4 rises as the engine E warms up, the temperature sensing portion 25 in the storage chamber 27 adjacent to the intake port 6i is heated from the inner wall of the storage chamber 27 and is movable. As described above, the elastic bag 34 is squeezed by the thermal expansion of the wax 35 in the cylinder 31 and the movable cylinder 31 resists the elastic force of the return spring 38 due to the reaction of trying to push out the fixed piston 33. The forward movement of the movable cylinder 31 advances in the F direction, and the first lever 41 is rotated in the arrow R direction via the rod 43. Since the first lever 41 and the second lever 42 are initially in a connected state in which the contact portions 41a and 42a are in contact with each other by the urging force of the connection spring 44, as shown in FIG. Also, the operating arm 42c is rotated integrally with the first lever 41 so that the driven pin 22c, that is, the choke lever 22 is rotated in the opening direction of the choke valve 19 against the urging force of the choke return spring 21. become. Accordingly, the opening degree of the choke valve 19 increases as the temperature of the storage chamber 27 increases, so that the negative pressure on the fuel nozzle in the intake passage 11 is reduced as the warm-up operation of the engine E progresses. Thus, it is possible to appropriately correct the air-fuel ratio of the air-fuel mixture generated in the intake passage 11 by reducing the fuel ejection amount of the fuel nozzle. Then, when the warm-up operation of the engine E is completed, the temperature in the accommodation chamber 27 is sufficiently increased, and the choke valve 19 is controlled to be fully opened as shown in FIG.

  As described above, when the choke valve 19 is opened by the choke lever 22, the choke lever 22 moves away from the drive arm 24 of the throttle lever 23 as shown in FIG. After the warm-up operation is completed, the output control lever 56 is returned to the idling position, and the load of the governor spring 54 is controlled to the minimum, so that the choke lever 55 is not obstructed. The throttle lever 23 can be rotated to the idle opening of the throttle valve 20 by the output.

  When the temperature of the cylinder head 4 further rises and the temperature of the storage chamber 27 also rises, the movable cylinder 31 advances excessively due to further thermal expansion of the wax 35, and the first lever 41 is moved by the arrow R through the rod 43. The second lever 42 is further prevented from rotating by the choke lever 22 in the fully open position, so that only the first lever 41 is connected to the coupling spring 44 as shown in FIG. The contact portion 41a of the first lever 41 moves away from the contact portion 42a of the second lever 42 by rotating in the direction of the arrow R while extending the distance. Therefore, the overstroke operation of the movable cylinder 31 of the temperature sensing unit 25 is absorbed by the extension of the coupling spring 44. This means that loads greater than the set load of the connecting spring 44 do not act on each part from the auto choke device A to the choke valve 19, thereby avoiding the occurrence of excessive stress in each part and the durability of each part. Sex can be secured. In addition, since the first and second levers 41 and 42 that can rotate relative to each other are attached to the bracket 10a via the common pivot 40, the number of parts of the output portion 26 can be reduced and the structure can be simplified. .

  After that, when the operation of the engine E is stopped, as long as the engine E continues to be in a high temperature state, the inside of the storage chamber 27 continues to be in a high temperature state. The choke valve 19 is held open via the output unit 26. Therefore, when the engine E in a high temperature state is restarted, the open state of the choke valve 19 can be secured to prevent the air-fuel mixture from being excessively concentrated and to improve the restartability.

  When the engine E is cooled after being shut down, in the temperature sensing unit 25, the movable cylinder 31 moves backward due to the thermal contraction of the wax 35 and the action of the return spring 38, so that the output unit 26 is driven by the choke return spring 21. Then, the choke lever 22 is allowed to rotate in the closing direction of the choke valve 19.

  In addition, this invention is not limited to the said Example, A various design change is possible in the range which does not deviate from the summary. For example, instead of the centrifugal governor device G, an electronic type or other type of governor device may be provided. Instead of the wax-type auto choke device A, an electric heating type or other type of auto choke device may be provided.

The front view which cut through a part of general purpose engine concerning the present invention longitudinally. The principal part enlarged view of FIG. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. FIG. 5 is a sectional view taken along line 5-5 of FIG. FIG. 6 is a sectional view taken along line 6-6 of FIG. FIG. 7 is an operation explanatory diagram of the auto choke device corresponding to FIG. 6. Another action explanatory view of an auto choke device. Another operation explanatory view of an auto choke device. The enlarged view of the temperature sensing part in the auto choke apparatus in FIG. Action explanatory drawing corresponding to FIG. The schematic side view of a governor apparatus. FIG. 13 is an enlarged sectional view taken along line 13-13 of FIG. FIG. 14 is a sectional view taken along line 14-14 of FIG. FIG. 15 is a sectional view taken along line 15-15 in FIG. 13;

A ... Auto choke device C ... Vaporizer Ca ... Evaporator body E ... Engine G ... Governor device 19 ... Choke valve 19a ...・ Valve shaft 20 ... Throttle valve 21 ... Choke return spring
21a ... Coil portion of choke return spring
21b: one end of the choke return spring
21c: the other end 22 of the choke return spring ... the choke lever 23 ... the throttle lever 61 ... the collar

Claims (1)

The throttle valve (20) is connected to a throttle lever (23) that opens and closes. When the engine (E) is stopped, the throttle valve (20) is opened. When the engine (E) is operated, the throttle valve is set according to the rotational speed. governor for opening and closing (20) and (G), the choke valve and a choke lever (22) a choke valve for opening and closing (19) the choke return spring biases the closing direction (19) (21), Ji Yokureba ( 22) and an auto choke device (A) that opens the choke valve (19) in response to an increase in the engine temperature. The choke lever (22) is connected to the valve shaft (19a) of the choke valve (19). In the control device for the carburetor connected to the outer end protruding above the carburetor body (Ca),
During the cold operation of the engine (E), the choke lever (22) is interlocked with the throttle lever (23) being rotated by the governor device (G) to the idle opening position of the throttle valve (20) or in the vicinity thereof. ) Is configured to rotate to the intermediate opening position of the choke valve (19), and the throttle lever (23) is configured,
A collar rotatably fitted to the valve shaft (19a) of the choke valve (19) between the choke lever (22) and the upper surface of the vaporizer body (Ca) so as to be able to rotate relative to the choke lever (22). (61) interposed,
The choke return spring (21) is constituted by a torsion coil spring in which both end portions (21b, 21c) are respectively locked to the choke lever (22) and the upper surface of the vaporizer body (Ca). (21a), characterized in that it is surrounded concentrically on the outer peripheral surface of the collar (61), the control equipment of the vaporizer.

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