JP2009264264A - General-purpose internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a general-purpose internal combustion engine provided with a choke valve on-off mechanism driving a choke valve without newly employing an actuator. <P>SOLUTION: The general-purpose internal combustion engine, provided with a throttle valve 60 and an electric motor 70 driving the throttle valve 60 includes: a throttle valve on-off mechanism 72 opening and closing the throttle valve between a full closed position and a position exceeding a full opened position by a prescribed opening according to operation of the electric motor; and the choke valve on-off mechanism 90 opening and closing the choke valve 62 in linking with operation of the throttle valve on-off mechanism. The choke valve on-off mechanism 90 retains the choke valve 62 at the full opened position when the throttle valve 60 is between the full closed position and the full opened position, and opens and closes the choke valve 62 between the full opened position and full closed position when the throttle valve is at the full opened position and a position exceeding the full opened position by the prescribed opening. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a general-purpose internal combustion engine, and more particularly to a general-purpose internal combustion engine provided with an actuator that drives a throttle valve.

  Conventionally, in general-purpose internal combustion engines that are used as a drive source in various applications such as generators and agricultural machinery, an electronically controlled throttle device (electronic governor) that opens and closes a throttle valve with an actuator such as a stepping motor is used. It is widely performed to control the rotational speed with high accuracy.

By the way, in recent years, a technique for improving engine startability by using an auto choke device that opens and closes a choke valve of a general-purpose internal combustion engine with an actuator has been proposed. When this auto choke device is provided in the above-described general-purpose internal combustion engine, for example, as in the technique described in Patent Document 1, it is common to newly install an actuator for a choke valve in addition to an actuator for a throttle valve.
JP 2007-23838 A (paragraphs 0022, 0036, FIG. 2, etc.)

  However, when the actuator for the choke valve is added as in the technique described in Patent Document 1, a space for arranging the actuator is required, which causes a problem that the entire general-purpose internal combustion engine is enlarged.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a general-purpose internal combustion engine that includes the choke valve opening / closing mechanism that drives the choke valve without newly using an actuator.

  In order to solve the above-described object, according to claim 1, in a general-purpose internal combustion engine including a throttle valve disposed in an intake passage and an actuator for driving the throttle valve, the throttle valve and the actuator are connected. And a throttle valve opening / closing mechanism for opening / closing the throttle valve between a fully closed position and a position where the fully opened position exceeds a predetermined opening according to the operation of the actuator, and a choke valve disposed in the intake passage, A choke valve opening / closing mechanism connected to the throttle valve opening / closing mechanism and the choke valve and opening / closing the choke valve in conjunction with the operation of the throttle valve opening / closing mechanism, and the choke valve opening / closing mechanism includes: When between the fully closed position and the fully open position, The choke valve is opened and closed between the fully open position and the fully closed position when the throttle valve is in the fully open position while the throttle valve is between the fully open position and the fully open position exceeding a predetermined opening degree. Configured.

  In the general-purpose internal combustion engine according to claim 2, the choke valve opening / closing mechanism includes a link having one end connected to the choke shaft supporting the choke valve and the other end connected to the throttle valve opening / closing mechanism. Thus, the link is displaced in conjunction with the operation of the throttle valve opening / closing mechanism and rotates the choke shaft to open / close the choke valve.

  In the general-purpose internal combustion engine according to claim 1, a throttle valve opening / closing mechanism that opens and closes the throttle valve between a fully closed position and a position exceeding the fully opened position in accordance with an operation of an actuator that drives the throttle valve; A choke valve opening / closing mechanism that opens and closes the choke valve in conjunction with the operation of the throttle valve opening / closing mechanism, and the choke valve opening / closing mechanism fully opens the choke valve when the throttle valve is between the fully closed position and the fully open position. The choke valve is configured to open and close between the fully open position and the fully closed position when the fully open position is between the fully open position and the position that exceeds the fully open position, that is, the throttle valve is opened from the fully open position. Further, the valve is opened and closed to a position exceeding a predetermined opening in the valve opening direction, and the throttle valve is a position where the fully open position exceeds a predetermined opening. In some cases, the choke valve is configured to open and close, so the choke valve can be driven by the actuator that drives the throttle valve. In other words, both the throttle valve and the choke valve are driven by a single actuator. Is possible. Thus, the choke valve can be driven without using a new actuator, and a space for arranging the actuator can be eliminated. In addition, since the actuator for the choke valve used in Patent Document 1 and the corresponding drive circuit and harness can be reduced, it is advantageous in terms of power consumption and cost.

  In the general-purpose internal combustion engine according to claim 2, the choke valve opening / closing mechanism includes a link having one end connected to the choke shaft and the other end connected to the throttle valve opening / closing mechanism, and the link is a throttle valve opening / closing mechanism. Since the choke valve is opened and closed by displacing in conjunction with the movement of the choke shaft and rotating the choke shaft, the choke valve can be driven with a simple configuration in addition to the above effects. Space can be saved.

  The best mode for carrying out a general-purpose internal combustion engine according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is an overall view of a general-purpose internal combustion engine according to a first embodiment of the present invention.

  In FIG. 1, reference numeral 10 denotes a general-purpose internal combustion engine (hereinafter referred to as “engine”). The engine 10 is an air-cooled four-cycle single-cylinder OHV type engine (with a displacement of 440 cc, for example), and is used as a drive source in various applications such as a generator and an agricultural machine.

  The engine 10 includes a single cylinder (cylinder) 12, and a piston 14 is accommodated therein so as to be capable of reciprocating. An intake valve 20 and an exhaust valve 22 are disposed at a position facing the combustion chamber 16 of the engine 10, and opens and closes between the combustion chamber 16 and the intake port 24 or the exhaust port 26. A temperature sensor 28 is disposed in the vicinity of the cylinder 12 and generates an output indicating the temperature of the engine 10.

  The piston 14 is connected to a crankshaft 30, and the crankshaft 30 is connected to a camshaft 34 via a cam gear mechanism 32. Further, a load (not shown) such as a generator is connected to one end of the crankshaft 30, while a flywheel 36 is attached to the other end.

  A plurality of permanent magnets 38 are arranged inside the flywheel 36, and a power coil (power generation coil) 40 and a fuel cut solenoid valve coil (described later) are arranged so as to face the permanent magnet 38 inside the flywheel 36. 4 (hereinafter referred to as “FS coil”), the pulsar coil 42 is installed so as to face the permanent magnet 38 on the outside. The power coil 40, the pulsar coil 42, and the FS coil generate an output (alternating current) synchronized with the rotation of the crankshaft 30. In addition, a recoil starter 44 that starts the engine 10 by an operator's manual operation is attached to the crankshaft 30.

  A carburetor 46 is connected to the intake port 24.

  FIG. 2 is an enlarged cross-sectional view of the carburetor 46 shown in FIG.

  As shown in FIG. 2, the carburetor 46 integrally includes an intake passage 50, a motor case 52, and a carburetor assembly 54. The intake passage 50 has a downstream side connected to the intake port 24 via an insulator 56 and an upstream side connected to an air cleaner (not shown) via an air cleaner elbow 58. A throttle valve 60 is disposed in the intake passage 50, and a choke valve 62 is disposed upstream of the throttle valve 60 in the intake passage 50. Further, the intake passage 50 is reduced in diameter between the throttle valve 60 and the choke valve 62 to form a venturi 64.

  A cover 66 is attached to the motor case 52, and an electric motor (actuator) 70 that drives the throttle valve 60 and the choke valve 62 is disposed in an internal space formed by the motor case 52 and the cover 66. The electric motor 70 is specifically a stepping motor and includes a stator and a rotor around which coils are wound. The electric motor 70 is connected to the throttle valve 60 via a throttle valve opening / closing mechanism (gear mechanism) 72.

  FIG. 3 is a plan view of the carburetor 46 shown in FIG. 2 with the cover 66 of the motor case 52 removed. FIG. 3 shows a state in which the throttle valve 60 is in the fully closed position and the choke valve 62 is in the fully open position, as indicated by an imaginary line.

  As shown in FIGS. 2 and 3, the throttle valve opening / closing mechanism 72 includes four gears. Each gear is an external gear. Specifically, a first gear 74 is attached to the output shaft 70 </ b> S of the electric motor 70, and the first gear 74 is meshed with a second gear 76 that is rotatably supported inside the motor case 52. The A third gear (eccentric gear) 78 that rotates integrally with the second gear 76 is attached coaxially with the second gear 76. As can be seen from FIG. 3, the teeth of the third gear 78 are formed only on a part of the outer periphery of the third gear 78 (part connected to a fourth gear (described later)).

  The third gear 78 meshes with a fourth gear (eccentric gear) 82 attached to a throttle shaft 80 that supports the throttle valve 60. As a result, the output of the electric motor 70 is transmitted to the throttle shaft 80 while being decelerated in accordance with the gear ratio of the gears 74, 76, 78, 82, thereby opening and closing the throttle valve 60. One of the characteristic features of the throttle valve opening / closing mechanism 72 according to this embodiment is that the throttle valve 60 is opened / closed between a fully closed position and a position where the fully opened position exceeds a predetermined opening according to the operation of the electric motor 70, That is, the throttle valve 60 is opened and closed from the fully opened position to a position exceeding a predetermined opening in the valve opening direction, which will be described later.

  A throttle return spring 84 (shown in FIG. 2) is disposed on the outer periphery of the throttle shaft 80. The throttle return spring 84 is a torsion coil spring. One end of the throttle return spring 84 is connected to a fourth gear 82 attached to the throttle shaft 80, and the other end is connected to a hook pin 86 (shown in FIG. 2) protruding inside the motor case 52. Connected. The winding direction of the throttle return spring 84 is set to a direction in which the throttle valve 60 is opened via the throttle shaft 80.

  A choke valve 62 is connected to the throttle valve opening / closing mechanism 72 configured as described above via a choke valve opening / closing mechanism 90. Therefore, the electric motor 70 is connected to the throttle valve 60 via the throttle valve opening / closing mechanism 72 and also connected to the choke valve 62 via the throttle valve opening / closing mechanism 72 and the choke valve opening / closing mechanism 90.

  The choke valve opening / closing mechanism 90 is attached to a choke shaft 92 that supports the choke valve 62 and rotates the choke shaft 92. The arm 94 and the throttle valve opening / closing mechanism 72 (more precisely, the throttle valve opening / closing mechanism 72 It consists of a link 96 connecting the third gear 78).

  The link 96 is supported inside the motor case 52 so as to be rotatable about the rotation shaft 100. In the link 96, an end (one end) 96a on the arm 94 side is provided with a first pin 96b extending upward in FIG. The first pin 96 b is inserted through a long hole 94 a formed in the arm 94.

  In the link 96, a second pin 96d protrudes upward from an end (other end) 96c on the third gear 78 side in FIG. The second pin 96d is brought into contact with a portion where teeth are not formed on the outer periphery of the third gear 78. The portion where the teeth are not formed on the outer periphery of the third gear 78 (that is, the portion where the second pin 96d abuts) has a substantially disc shape and includes a concave portion. Hereinafter, a concave portion formed on the outer periphery of the third gear 78 is referred to as a “first contact portion” and is denoted by reference numeral 78a. Further, the remaining portion (substantially disk-shaped portion) other than the first contact portion 78a in the portion where the outer peripheral teeth of the third gear 78 are not formed is referred to as a “second contact portion”, which is denoted by reference numeral 78b. Show. The positions where the first and second contact portions 78a and 78b are formed on the outer periphery of the third gear 78 will be described later.

  As shown in FIG. 2, a choke return spring 102 is disposed on the outer periphery of the choke shaft 92. Similarly to the throttle return spring 84, the choke return spring 102 is also a torsion coil spring. One end of the choke return spring 102 is connected to the arm 94, and the other end is connected to a hook pin 104 protruding inside the motor case 52. The winding direction of the choke return spring 102 is set to a direction in which the choke valve 62 is closed via the choke shaft 92.

  In the choke valve opening / closing mechanism 90, the choke valve 62 is provided with a choke return spring 102 that urges the choke valve 62 in the valve closing direction (fully closed position). Is transmitted to. Accordingly, a counterclockwise force acts on the link 96 around the rotation shaft 100, so that the second pin 96 d of the link 96 is connected to the outer peripheral surface of the third gear 78 (specifically, the first or the second 2 abutting portions 78a and 78b), while being always pressed (pressed).

  In this way, the link 96 has one end 96a connected to the choke shaft 92 via the first pin 96b and the arm 94, and the other end 96c connected to the throttle valve opening / closing mechanism 72 (via the second pin 96d). Precisely, it is connected (contacted) to the first contact portion 78a or the second contact portion 78b) of the third gear 78.

  Although not shown, the carburetor assembly 54 is connected to a float chamber connected to the fuel tank, a main nozzle connected to the float chamber via the main jet and the main fuel passage, and a slow fuel passage branched from the main fuel passage. An idle port and a slow port. The main nozzle is disposed at a position facing the venturi 64, while the idle port and the slow port are disposed at a position facing the vicinity of the throttle valve 60.

  When the opening degree of the throttle valve 60 is large, fuel is injected from the main nozzle by the negative pressure of the intake air passing through the venturi 64, and an air-fuel mixture is generated. On the other hand, when the opening degree of the throttle valve 60 is small, the fuel is injected from the idle port or the slow port by the negative pressure of the intake air passing through the throttle valve 60. Further, when the choke valve 62 is closed, the negative pressure in the intake passage 50 caused by the lowering of the piston 14 increases, so that the fuel injection amount increases and the air-fuel ratio is enriched. Hereinafter, a state in which the air-fuel ratio in the intake passage 50 is enriched is referred to as a “rich air-fuel ratio state”.

  In FIG. 2, reference numeral 106 denotes a fuel cut solenoid valve (hereinafter referred to as “FS valve”). A valve portion (not shown) of the FS valve 106 is disposed between the float chamber and the main jet, and closes when the coil (shown in FIG. 4 described later) is energized to block the passage of fuel.

  Returning to the description of FIG. 1, the air-fuel mixture generated as described above is sucked into the combustion chamber 16 through the intake port 24 and the intake valve 20. The air-fuel mixture sucked into the combustion chamber 16 is ignited and burned by a spark plug (shown in FIG. 4 described later), and the generated combustion gas passes through an exhaust valve 22, an exhaust port 26, a silencer (not shown), and the like. It is discharged outside the engine 10.

  A rotation speed setting volume 110 is disposed at a position that can be operated by the operator, and an output indicating the target engine rotation speed is generated according to the operation of the operator. Outputs of the temperature sensor 28, the power coil 40, the pulsar coil 42, and the rotation speed setting volume 110 are input to an ECU (Electronic Control Unit) 112 formed of a microcomputer.

  A combination switch 114 is disposed at a position that can be operated by the operator. The combination switch 114 is connected to the ECU 112. The ECU 112 controls the operation of the engine 10 (for example, the operation of the electric motor 70) based on the position of the combination switch 114 and various inputs by the operator.

  FIG. 4 is an explanatory diagram showing the configuration of the ECU 112 and the combination switch 114.

  As shown in FIG. 4, ECU 112 includes rectifier circuit 116, NE (engine speed) detection circuit 120, and control circuit 122. The output of the power coil 40 is input to the rectifier circuit 116, converted into a 12V DC current, and supplied as an operating current to each part of the engine 10 including the ECU 112 via a circuit (not shown). The output of the power coil 40 is also input to the NE detection circuit 120 and converted into a pulse signal. The pulse signal is input to the control circuit 122, where the engine speed is detected. The ECU 112 further includes a signal shaping circuit 124 and an ignition circuit 126. The output of the pulsar coil 42 is input to a signal shaping circuit 124 where it is shaped into an ignition signal synchronized with the rotation of the crankshaft 30 and input to the ignition circuit 126 and the control circuit 122.

  The combination switch 114 includes first and second switches 114a and 114b. In FIG. 4, the switches 114a and 114b when the combination switch 114 is operated to the off position are indicated by solid lines, and when the combination switch 114 is operated to the on position, they are indicated by imaginary lines.

  The first switch 114 a is interposed between the FS coil 130 and the FS valve (specifically, the coil) 106. When the second switch 114 b is turned on, a DC current of 12 V generated from the output of the power coil 40 is input to the control circuit 122 and the DC / DC converter 132. The DC / DC converter 132 is connected to the primary coil of the ignition coil 136 via the capacitor 134 and charges the capacitor 134. The secondary coil of the ignition coil 136 is connected to the spark plug 140, and the capacitor 134 is grounded via the thyristor 142.

  The ignition circuit 126 energizes the gate of the thyristor 142 in accordance with the ignition signal from the signal shaping circuit 124 or the control circuit 122, discharges the electric charge charged in the capacitor 134, and energizes the primary coil of the ignition coil 136. Along with this, a high voltage is generated in the secondary coil and a spark is generated between the electrodes of the spark plug 140 to ignite the air-fuel mixture in the combustion chamber 16.

  The temperature sensor 28 and the rotation speed setting volume 110 are connected to the control circuit 122. The control circuit 122 determines target openings of the throttle valve 60 and the choke valve 62 based on outputs from the temperature sensor 28, the rotation speed setting volume 110, the NE detection circuit 120, and the like, and performs control according to the determined target opening. A signal is output to the motor driver 144 to operate the electric motor 70, and the valves 60 and 62 are opened and closed to adjust the engine speed and the amount of fuel supplied to the engine 10.

  When the combination switch 114 is operated to the on position by the operator, the first switch 114a is turned off, and the supply of the operating current to the FS valve 106 is cut off. The FS valve 106 is a normally open type, and enables fuel injection from the carburetor 46 when the supply of operating current is interrupted. On the other hand, when the second switch 114b is turned on and the recoil starter 44 is operated in this state, the power coil 40 and the pulsar coil 42 generate outputs as the crankshaft 30 rotates, and a 12V DC current and an ignition signal are generated. The engine 10 is generated (formed), the ECU 112 is started, and the engine 10 is started.

  When the combination switch 114 is operated to the off position, the second switch 114b is turned off, whereby the control circuit 122, which has been cut off from the supply of the operating current, performs the ignition cut and stops the engine 10. In addition, the first switch 114a is turned on, the FS coil 130 and the FS valve 106 are conducted, and fuel cut is performed. In other words, since the rotation of the crankshaft 30 does not stop immediately even after the ignition cut is performed, the power generation of the FS coil 130 is continued. Close the valve (fuel cut).

  Next, the opening / closing operation of the throttle valve 60 and the choke valve 62 will be described with reference to FIG. 3 and FIG. 5 and thereafter, focusing on the operations of the electric motor 70, the throttle valve opening / closing mechanism 72, and the choke valve opening / closing mechanism 90.

  FIG. 5 is an explanatory diagram showing the characteristics of the opening / closing operation of the throttle valve 60 and the choke valve 62.

  When the throttle valve 60 is in the fully closed position, the electric motor 70 rotates the throttle shaft 80 via the first to fourth gears 74, 76, 78, 82 of the throttle valve opening / closing mechanism 72, and the throttle valve 60. Is closed to the fully closed position shown in FIG. 3 and FIG. At this time, as can be seen from FIG. 3, the second pin 96d of the link 96 is in contact with the second contact portion 78b of the third gear 78, and the choke valve 62 is in the fully open position.

  When opening the throttle valve 60 from the fully closed position to the fully opened position, the electric motor 70 rotates the first to fourth gears 74, 76, 78, and 82 in the directions indicated by the arrows in FIG. The throttle shaft 80 is rotated counterclockwise, and the throttle valve 60 is opened to the fully open position. At this time, the second pin 96d slides to the vicinity of the first contact portion 78a, but is still in contact with the second contact portion 78b, and therefore also shown in FIG. Thus, the choke valve 62 is held in the fully open position. Thus, the choke valve opening / closing mechanism 90 holds the choke valve 62 in the fully open position when the throttle valve 60 is between the fully closed position and the fully open position.

  Also, when the choke valve 62 is closed to enrich the air-fuel ratio, such as when the engine 10 is started, the electric motor 70 operates the throttle valve opening / closing mechanism 72 and displaces the link 96 in conjunction with it to move the choke shaft 92 Is used to open and close the choke valve 62. Specifically, the electric motor 70 rotates the gears 74, 76, 78, and 82 in the directions indicated by the arrows in FIG. 7 to further rotate the throttle shaft 80 counterclockwise to fully open the throttle valve 60. The valve is opened to a position exceeding the predetermined opening degree α (hereinafter referred to as “over fully open position”).

  At this time, the second pin 96d slides to the first contact portion 78a by the rotation of the third gear 78. Thereby, the link 96 is displaced counterclockwise around the rotation shaft 100, and the first pin 96b displaces the arm 94 while sliding in the long hole 94a. Due to the displacement of the arm 94, the choke shaft 92 is rotated clockwise in the figure, so that the choke valve 62 is closed to the fully closed position as shown in FIG.

  As described above, the positions at which the first and second contact portions 78a and 78b are formed in the third gear 78 are determined when the second pin 96d contacts the second contact portion 78b, that is, 3 or 6, the choke valve 62 is in the fully open position, the third gear 78 is rotated clockwise in the drawing by the electric motor 70, and the second pin 96 d is in the first contact position. When contacting the contact portion 78a (in the state shown in FIG. 7), the choke valve 62 is set to the fully closed position.

  As described above and as shown in FIGS. 5A to 5C, the choke valve opening / closing mechanism 90 opens and closes the choke valve 62 in conjunction with the operation of the throttle valve opening / closing mechanism 72. More specifically, the throttle valve When 60 is between the fully closed position and the fully open position, the choke valve 62 is held in the fully open position, while the throttle valve 60 is between the fully open position and the over fully open position (the position where the fully open position exceeds the predetermined opening α). In some cases, the choke valve 62 is configured to open and close between a fully open position and a fully closed position.

  In the above description, the operation of the choke valve 62 has been described in two types, the fully open position and the fully closed position. However, since the first contact portion 78a is formed in a concave shape, the second pin 96d and the first contact By appropriately adjusting the contact position with the contact portion 78a, the choke valve 62 can be set to an arbitrary opening degree. That is, the choke valve 62 can be freely opened and closed between the fully open position and the fully closed position by appropriately adjusting the throttle valve 60 between the fully open position and the over fully open position.

  Next, the opening / closing operation of the throttle valve 60 and the choke valve 62 when the engine 10 is started will be described.

  FIG. 8 is a flowchart showing the control of the operation of the throttle valve 60 when the engine 10 is started, among the operations of the ECU 112. The illustrated program is executed only once when the engine 10 is started. Before the engine 10 is started, the throttle valve 60 and the choke valve 62 are in the state shown in FIGS. 7 and 5C. Specifically, the throttle valve 60 is set to the fully open position by the biasing force of the throttle return spring 84. At the same time, the choke valve 62 is brought into a fully closed position by the choke return spring 102.

  Hereinafter, the opening / closing operation of the throttle valve 60 and the choke valve 62 will be described with reference to the flowchart of FIG. After the combination switch 114 is operated to the on position by the operator, the recoil starter 44 is operated, the power coil 40 starts generating power, and the ECU 112 is activated. First, in S10, the throttle valve 60 is in the over fully open position. The operation of the electric motor 70 is controlled so as to be driven (opened / closed) between the fully opened position and the fully opened position. By driving the throttle valve 60 as described above, the choke valve 62 is opened and closed between the fully closed position and the fully open position, as shown in FIGS. As a result, the air-fuel ratio in the intake passage 50 is enriched (a rich air-fuel ratio state is set), and the startability of the engine 10 is improved.

  Next, the routine proceeds to S12, where it is determined whether or not the choke is necessary, in other words, whether or not the warm-up operation is finished and the rich air-fuel ratio state by the choke valve 62 needs to be stopped. The determination in S12 is made based on the output of the NE detection circuit 120, and when the engine speed exceeds a predetermined value (for example, 3000 rpm), it is determined that choke is not necessary.

  When the result in S12 is negative, the process returns to S10. When the result is affirmative, the process proceeds to S14, where the normal control of the throttle valve 60 is executed, thereby stopping the rich air-fuel ratio state by the choke valve 62. Specifically, the throttle valve 60 is driven between the fully closed position and the fully opened position (more precisely, the throttle valve 60 is set to the target in order to maintain the target engine speed input by the speed setting volume 110). The operation of the electric motor 70 is controlled so that the opening degree is reached. By driving the throttle valve 60 between the fully closed position and the fully open position, the choke valve 62 is held in the fully open position as shown in FIGS. Is canceled.

  Next, the opening / closing operation of the throttle valve 60 and the choke valve 62 when the engine 10 is stopped will be described.

  FIG. 9 is a flowchart showing control of the operation of the throttle valve 60 when the engine 10 is stopped, among the operations of the ECU 112. The illustrated program is executed in the ECU 112 at predetermined intervals (for example, 100 msec).

  First, in S100, it is determined whether or not an instruction to stop the engine 10 has been input, specifically, whether or not the combination switch 114 has been operated to the off position. When the result in S100 is negative, the subsequent processing is skipped, while when the result is positive, the process proceeds to S102 to control the operation of the electric motor 70 so that the throttle valve 60 is driven (opened) to the over fully open position. By driving the throttle valve 60 as described above, the choke valve 62 is closed to the fully closed position as shown in FIG.

  Thus, in the engine according to the first embodiment of the present invention, the throttle valve 60 exceeds the fully closed position and the fully opened position beyond the predetermined opening α in accordance with the operation of the electric motor 70 that drives the throttle valve 60. A throttle valve opening / closing mechanism 72 that opens and closes between positions (over fully open positions), and a choke valve opening / closing mechanism 90 that opens and closes the choke valve 62 in conjunction with the operation of the throttle valve opening / closing mechanism 72. However, when the throttle valve 60 is between the fully closed position and the fully open position, the choke valve 62 is held at the fully open position, while the fully open position and the position where the fully open position exceeds the predetermined opening α (over full open position). In some cases, the choke valve 62 is configured to open and close between a fully open position and a fully closed position, that is, the throttle valve 60 is fully opened. And the choke valve 62 is opened and closed when the throttle valve 60 is in the over fully open position, so that the electric motor 70 for driving the throttle valve 60 is opened. Thus, the choke valve 62 can also be driven. In other words, both the throttle valve 60 and the choke valve 62 can be driven by one electric motor 70. As a result, the choke valve 62 can be driven without using a new electric motor, and a space for arranging the electric motor can be eliminated. Further, the electric motor for the choke valve used in Patent Document 1, the corresponding motor driver (drive circuit) (both shown by imaginary lines in FIG. 4) and harnesses can be reduced, which is advantageous in terms of power consumption and cost. It is.

  The choke valve opening / closing mechanism 90 includes a link 96 having one end 96a connected to the choke shaft 92 and the other end 96c connected to the throttle valve opening / closing mechanism 72. The link 96 operates the throttle valve opening / closing mechanism 72. Since the choke valve 62 is opened and closed by rotating the choke shaft 92 by interlocking displacement, the choke valve 62 can be driven with a simple configuration, and further space saving can be achieved. Can do.

  Next, an engine according to a second embodiment of the present invention will be described.

  FIG. 10 is a schematic diagram showing the vicinity of the intake passage 50 of the engine according to the second embodiment of the present invention. In addition, about the structure common to 1st Example, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The description will focus on the differences from the first embodiment. In the second embodiment, the fuel cut is performed by the fuel cut needle valve 150 instead of the FS valve 106, and the fuel is cut. The cut needle valve 150 was configured to be driven by the arm 94. In the second embodiment, it is assumed that the choke valve 62 is manually operated by an operator.

  More specifically, the fuel cut needle valve 150 is connected to the arm 94, and the injection port 152a of the main nozzle 152 can be sealed in accordance with the rotation (displacement) of the arm 94. More specifically, when the throttle valve 60 is between the fully closed position and the fully open position, the fuel cut needle valve 150 is positioned so as to open the injection port 152a, and fuel can be injected from the main nozzle 152. State. On the other hand, when the throttle valve 60 is in the over fully open position, the arm 94 rotates and the fuel cut needle valve 150 moves downward in the drawing to seal the injection port 152a and shut off the fuel supply. .

  Accordingly, when the throttle valve 60 is driven between the fully closed position and the fully opened position, that is, when the normal control of the throttle valve 60 is executed, the fuel cut needle valve 150 is positioned so as to open the injection port 152a. Therefore, fuel can be supplied from the main nozzle 152. Further, if the throttle valve 60 is driven to the fully open position when the engine 10 is stopped, the fuel cut needle valve 150 moves downward to seal the injection port 152a. That is, fuel cut can be executed.

  As described above, in the engine according to the second embodiment of the present invention, both the throttle valve 60 and the fuel cut needle valve 150 are driven by the electric motor 70. When an additional cutting device is installed, the fuel-cut needle valve 150 can be driven without using a new electric motor, so there is no need for a space for installing the electric motor for the fuel-cut needle valve. Space can be achieved.

  Since the remaining effects are the same as those of the first embodiment, description thereof is omitted.

  As described above, in the first embodiment of the present invention, the general-purpose internal combustion engine (engine) 10 including the throttle valve 60 disposed in the intake passage 50 and the actuator (electric motor) 70 that drives the throttle valve. The throttle valve is connected to the throttle valve and the actuator and opens / closes the throttle valve between a fully closed position and a position where the fully opened position exceeds a predetermined opening α (over fully opened position) in accordance with the operation of the actuator. A choke valve connected to the valve opening / closing mechanism 72, the choke valve 62 disposed in the intake passage, the throttle valve opening / closing mechanism and the choke valve, and opening / closing the choke valve in conjunction with the operation of the throttle valve opening / closing mechanism. An opening / closing mechanism 90 and the choke valve opening / closing mechanism When the throttle valve 60 is between the fully closed position and the fully open position, the choke valve 62 is held at the fully open position, while the throttle valve 60 opens the fully open position and the fully open position at a predetermined opening degree. The choke valve 62 is configured to open and close between the fully open position and the fully closed position when it is between the positions exceeding α.

  The choke valve opening / closing mechanism 90 has one end 96a connected to the choke shaft 92 that supports the choke valve 62, and the other end 96c connected to the throttle valve opening / closing mechanism 72 (more precisely, the throttle valve opening / closing mechanism 72). The link 96 is connected to a third gear 78), and the link 96 is displaced in conjunction with the operation of the throttle valve opening / closing mechanism 72 to rotate the choke shaft 92 to open / close the choke valve 62. It was configured as follows.

  In the above, the actuator (electric motor 70) for driving the throttle valve 60 and the like is a stepping motor. However, other electric motors or electromagnetic solenoids may be used, and the pump is driven by the electric motor. It may be a hydraulic device.

  Further, in conjunction with the operation of the throttle valve opening / closing mechanism 72, the choke valve 62 is driven in the first embodiment, and the fuel cut / needle valve 150 is driven in the second embodiment. You may comprise so that the cock valve to perform may be driven.

  Further, the fuel is supplied by the carburetor 46, but the present invention is not limited to this, and an injector (fuel injection valve) may be arranged in the intake port 24 to supply the fuel.

1 is an overall view of a general-purpose internal combustion engine (engine) according to a first embodiment of the present invention. It is an expanded sectional view of the carburetor shown in FIG. It is a top view which shows the state which removed the cover of the motor case of the carburetor shown in FIG. It is explanatory drawing which shows the structure of the electronic control unit and combination switch shown in FIG. It is explanatory drawing which shows the characteristic of the opening / closing operation | movement of the throttle valve and choke valve shown in FIG. It is a top view of the carburetor similar to FIG. It is a top view of the carburetor similar to FIG. 2 is a flowchart showing control of the operation of a throttle valve at the time of starting a general-purpose internal combustion engine (engine) among the operations of the electronic control unit shown in FIG. 2 is a flowchart showing control of the operation of a throttle valve when the general-purpose internal combustion engine (engine) is stopped, among the operations of the electronic control unit shown in FIG. 1. It is a schematic diagram which shows the intake passage vicinity of the general purpose internal combustion engine (engine) which concerns on 2nd Example of this invention.

Explanation of symbols

  10 engine (general-purpose internal combustion engine), 50 intake passage, 60 throttle valve, 62 choke valve, 70 electric motor (actuator), 72 throttle valve opening / closing mechanism, 90 choke valve opening / closing mechanism, 92 choke shaft, 96 link, 96a (link ) One end, 96c The other end (of the link)

Claims (2)

  In a general-purpose internal combustion engine that includes a throttle valve disposed in an intake passage and an actuator that drives the throttle valve, the throttle valve is connected to the throttle valve and the actuator, and the throttle valve is fully closed according to the operation of the actuator. A throttle valve opening / closing mechanism that opens and closes between a position exceeding a predetermined opening degree and a fully open position; a choke valve disposed in the intake passage; and the throttle valve opening / closing mechanism and the choke valve connected to the throttle valve opening / closing A choke valve opening / closing mechanism that opens and closes the choke valve in conjunction with the operation of the mechanism, and the choke valve opening / closing mechanism is configured such that the choke valve opens when the throttle valve is between the fully closed position and the fully open position. While holding the slot in the fully open position. A general-purpose internal combustion engine configured to open and close the choke valve between the fully open position and the fully closed position when a torque valve is between the fully open position and a position exceeding the fully open position by a predetermined opening degree. .   The choke valve opening / closing mechanism includes a link having one end connected to the choke shaft that supports the choke valve and the other end connected to the throttle valve opening / closing mechanism, and the link serves to operate the throttle valve opening / closing mechanism. The general-purpose internal combustion engine according to claim 1, wherein the choke valve is opened and closed by rotating the choke shaft in conjunction with the displacement.

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