JP2012202257A - Portable working machine having mounted thereon internal combustion engine with lubricating oil tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique relating to a portable working machine having mounted thereon an internal combustion engine provided with a lubricating oil tank, the technique being configured so that, when there is an abnormality in the amount of lubricating oil retained in the lubricating oil tank, the technique can accurately inform the user of the abnormality.SOLUTION: A portable working machine is provided with: an oil level sensor for detecting the level of lubricating oil retained in a lubricating oil tank; a rotational speed adjusting device capable of adjusting a rotational speed of the internal combustion engine; and a first warning device for informing the user of an abnormality in the level of the lubricating oil. The portable working machine automatically inspects the level of the lubricating oil, which is retained in the lubricating oil tank, during the period from the start of the internal combustion engine to the start of the work of the user. During the inspection of the level of the lubricating oil, if the value detected by the oil level sensor is not within a predetermined range, the portable working machine informs the user of the abnormality by means of the first warning device and prevents a rise in the rotational speed of the internal combustion engine by means of the rotational speed adjusting device.

Description

  The technique disclosed by this specification is related with the portable working machine carrying the internal combustion engine provided with a lubricating oil tank.

  In a portable working machine equipped with an internal combustion engine equipped with a lubricating oil tank, if the work is performed in a state where the lubricating oil stored in the lubricating oil tank is insufficient, problems such as seizure of the internal combustion engine may occur. However, in general, the fuel of the internal combustion engine is consumed quickly in such a portable work machine, but the lubricating oil of the internal combustion engine is not consumed so quickly, so the user of the portable work machine is interested in the shortage of fuel. However, they often do not pay much attention to the lack of lubricating oil. Thus, a technique for automatically inspecting the amount of lubricating oil in an internal combustion engine has been developed. A technique for automatically inspecting the amount of lubricating oil in an internal combustion engine is described in Patent Documents 1-6, for example.

Japanese Patent Application Laid-Open No. 60-30428 JP-A-3-31507 JP-A-3-31508 JP 2003-201944 A JP 2007-239460 A JP 2007-285277 A

  Even if the warning device informs the user that the amount of lubricating oil stored in the lubricating oil tank is insufficient, the user may perform work without noticing. For example, when a warning light is used to inform the user that the amount of lubricating oil is insufficient, the user is not always watching the warning light, and it is used even if the warning light is on. May not notice. Even when a warning alarm is used to notify the user, the noise generated by the internal combustion engine may be difficult to hear, and the user may not be aware even if the warning alarm is sounding.

  If the operation of the internal combustion engine is automatically stopped when the amount of lubricating oil stored in the lubricating oil tank is insufficient, it is possible to prevent the user from working in a state where the amount of lubricating oil is insufficient. . However, in this case, the user may misunderstand that the internal combustion engine has failed. In order to prompt the user to replenish the lubricating oil promptly, the user must be informed that the internal combustion engine is not faulty and the amount of lubricating oil stored in the lubricating oil tank is insufficient. It is necessary to inform accurately.

  This specification provides a technology that can accurately notify the user when there is an abnormality in the amount of lubricating oil stored in a lubricating oil tank in a portable work machine equipped with an internal combustion engine equipped with a lubricating oil tank. To do.

  The present specification discloses a portable working machine equipped with an internal combustion engine including a lubricating oil tank. The portable work machine includes an oil level sensor that detects a liquid level of the lubricating oil stored in the lubricating oil tank, a rotation speed adjusting device that can adjust a rotation speed of the internal combustion engine, and a liquid for lubricating oil to a user. A first warning device for notifying the position abnormality. The portable work machine automatically checks the level of the lubricating oil stored in the lubricating oil tank between the start of the internal combustion engine and the start of work by the user. In the portable work machine, when the detection value of the oil level sensor does not fall within a predetermined range during the inspection of the level of the lubricating oil, the first warning device notifies the user of the abnormality, In addition, an increase in the rotational speed of the internal combustion engine is suppressed by the rotational speed adjusting device.

  In the portable work machine described above, when the detection value of the oil level sensor does not fall within a predetermined range during the inspection of the level of the lubricating oil, in addition to notifying the abnormality by the first warning device, the rotation of the internal combustion engine The user is also notified of the abnormality by suppressing the increase in the number. With this configuration, even when the user is not aware of the abnormality notification by the first warning device, the noise and vibration from the internal combustion engine are different from the user's assumptions, and the user feels abnormal. Can be obtained. In addition, since the first warning device notifies the user of the abnormality of the lubricating oil level simultaneously with the suppression of the increase in the rotational speed of the internal combustion engine, the user who senses the abnormality misunderstands that the internal combustion engine has failed. There is nothing to do. When there is an abnormality in the amount of lubricating oil stored in the lubricating oil tank, it is possible to accurately notify the user.

  The term “portable work machine” as used herein means a work machine that is carried by a user and that uses the power of the internal combustion engine. For example, a brush cutter, a mower, or a spray machine. It may be a spreader, an engine blower, a dust collector, or the like.

  The “internal combustion engine” herein may be any engine that lubricates the internal members with the lubricating oil from the lubricating oil tank. For example, the internal combustion engine may be a 4-stroke cycle engine or a separate oil-feeding 2-stroke cycle engine. There may be.

  Here, the “lubricating oil tank” may be an oil pan provided at the lowermost part of the internal combustion engine or an oil tank provided outside the internal combustion engine.

  The “rotation speed adjusting device” here may be any apparatus as long as it can suppress an increase in the rotational speed of the internal combustion engine. For example, the ignition timing of the internal combustion engine ignition device may be advanced or retarded from that during normal operation to lower the rotational speed of the internal combustion engine, or the internal combustion engine ignition device ignition frequency may be reduced during normal operation. It may be reduced more. Alternatively, the control by the user's throttle operation is disabled, and the idling rotation of the internal combustion engine may be maintained.

  As used herein, the “first warning means” may be any device that notifies the user of a warning through vision or hearing, and may be a warning light that notifies the user of an abnormality by lighting, for example, or may be used by sounding. It may be a warning alarm informing the person of abnormality.

  The term “between the start of the internal combustion engine and the start of work by the user” here may be, for example, immediately after the start of the internal combustion engine, or when the internal combustion engine is started and is in an idling state. Therefore, it may be when the user performs an operation to increase the rotational speed of the internal combustion engine in order to start work.

  According to the technology disclosed in the present specification, in a portable working machine equipped with an internal combustion engine having a lubricating oil tank, when there is an abnormality in the amount of lubricating oil stored in the lubricating oil tank, the user is accurately notified. Can do.

It is a figure which shows the external appearance of the brush cutter 2,102,202 of Example 1,2,3. 1 is a front view of engines 6, 104, and 204 of Examples 1, 2, and 3. FIG. FIG. 3 is a longitudinal sectional view taken along line III-III in FIG. 2 showing an internal configuration of engines 6, 104, and 204 of Examples 1, 2, and 3. It is a figure which shows typically the lubricating oil circulation system of the engine 6,104,204 of Example 1,2. FIG. 3 is a block diagram illustrating a configuration of an oil level sensor unit 92 according to the first embodiment. 3 is a flowchart of an oil level inspection process according to the first embodiment. It is a block diagram which shows the structure of the oil level sensor unit 106 of Example 2. FIG. 6 is a flowchart of an oil level inspection process according to a second embodiment. It is a block diagram which shows the structure of the oil level sensor unit 206 of Example 3. FIG. 10 is a flowchart of an oil level inspection process according to a third embodiment.

  The portable work machine according to an embodiment further includes an operation stop device that stops the operation of the internal combustion engine, and a second warning device that notifies the user of an abnormality in the level of the lubricating oil. When a predetermined time has elapsed since the start of the abnormality notification by the first warning device, the operation of the internal combustion engine is stopped by the operation stop device, and the abnormality is notified to the user by the second warning device. By adopting such a configuration, the user can be surely notified that there is an abnormality in the amount of lubricating oil stored in the lubricating oil tank.

  The portable work machine according to an embodiment further includes an inclination sensor that detects an inclination angle of the lubricating oil tank, and the detected value of the inclination sensor is within a predetermined range before the inspection of the liquid level of the lubricating oil. If the detected value of the tilt sensor falls within the predetermined range, the first warning device notifies the user of the abnormality and the rotational speed of the internal combustion engine by the rotational speed adjusting device until the detected value of the tilt sensor falls within the predetermined range. To suppress the rise of With such a configuration, when the lubricating oil tank is not kept horizontal during the inspection of the lubricating oil level, the user can be urged to keep the lubricating oil tank horizontal. It is possible to prevent erroneous detection of the level of the lubricating oil in the oil level sensor by checking the level of the lubricating oil only when the lubricating oil tank is maintained horizontally.

  In the portable work machine according to an embodiment, the number of ignitions of the ignition device in the internal combustion engine is reduced from the normal time, thereby suppressing the rotation speed of the internal combustion engine from the normal time. By setting it as such a structure, consumption of the electric power in an ignition device can be suppressed and the electric power supplied to a 1st warning device or a 2nd warning device can be ensured.

Example 1
FIG. 1 shows the appearance of a brush cutter 2 according to an embodiment of a portable work machine. The brush cutter 2 includes an operating rod 4, an engine 6 attached to the rear end portion of the operating rod 4, a gear head 8 attached to the front end portion of the operating rod 4, and a disc-shaped cutting blade attached to the gear head 8. 10, a safety cover 12 attached to the front end portion of the operation rod 4 so as to cover the cutting blade 10, and a handle 14 attached to an intermediate portion of the operation rod 4.

  The operating rod 4 has a hollow pipe shape and extends linearly. A drive shaft (not shown) is accommodated in the operation rod 4. Torque output from the engine 6 is transmitted to the gear head 8 via the drive shaft inside the operation rod 4 to rotate the cutting blade 10. The handle 14 includes a throttle lever (not shown) that performs a throttle operation of the engine 6, a stop switch (not shown) that stops the engine 6, and the like. The handle 14 further includes a warning LED 16 and a warning alarm 18. The warning LED 16 notifies the user of an abnormality in the oil level of the lubricating oil of the engine 6 by lighting. The warning alarm 18 notifies the user of an abnormality in the oil level of the lubricating oil of the engine 6 by sounding.

  The engine 6 is a so-called 4-stroke cycle engine. As shown in FIG. 2, the engine 6 includes an engine body 20, a fuel tank 22 that stores fuel such as gasoline, an oil pan 24 that stores lubricating oil, and a recoil starter 26 for starting the engine 6. . Further, the engine 6 includes an air cleaner 28 that filters intake air, a carburetor 30 that mixes fuel and intake air, a muffler 32 that cools and discharges high-temperature combustion gas discharged from the engine 6 to the atmosphere, and oil that will be described later A level sensor unit 92 (see FIG. 5) is provided.

  The fuel sent from the fuel tank 22 is vaporized by the carburetor 30 and then sent to the combustion chamber 34 of FIG. 3 through the air supply port. The fuel mixture sent into the combustion chamber 34 is ignited by the spark plug 36 and burns, and the combustion pressure of the combustion gas at that time is transmitted to the piston 38 to rotate the crankshaft 40. The combustion gas in the combustion chamber 34 is sent to the muffler 32 in FIG. 2 through the exhaust port, and is released into the atmosphere as exhaust gas. An intake valve 42 is disposed between the combustion chamber 34 and the intake port in FIG. 3, and an exhaust valve 44 is disposed between the combustion chamber 34 and the exhaust port. The opening and closing operations of the intake valve 42 and the exhaust valve 44 are controlled by a rocker arm 46 that operates in conjunction with the rotation of the crankshaft 40. The intake valve 42 and the exhaust valve 44 alternately perform one opening / closing operation while the crankshaft 40 rotates twice.

  One end (the left end in FIG. 3) of the crankshaft 40 is connected to a drive shaft inside the operation rod 4 in FIG. 1 via a clutch (not shown). The other end of the crankshaft 40 (the right end in FIG. 3) is connected to the recoil starter 26. A magneto circuit 48 is disposed in the vicinity of the crankshaft 40. The magneto circuit 48 generates power using the rotation of the crankshaft 40 and supplies power to the spark plug 36 and an oil level sensor unit 92 described later. The magnet circuit 48 includes a timing adjustment circuit (not shown) and can adjust the ignition timing of the spark plug 36. Further, the magnet circuit 48 includes a rotation speed detection circuit (not shown), and can detect the rotation speed of the crankshaft 40. The crankshaft 40 is provided with a valve drive gear 50 (see FIG. 4). The camshaft 52 (see FIG. 4), the cam follower, and the push rod 54 that follow the valve drive gear 50 prevent the rotational movement of the crankshaft 40 from being locked. This is converted into a periodic motion of the arm 46.

  FIG. 4 shows a lubricating oil circulation system of the engine 6. A suction part 56 for sucking lubricating oil is provided inside the oil pan 24. The suction part 56 has a tube 58 formed of an elastic material such as rubber, and a weight 60 with a suction port attached to the tip of the tube 58. Even when the engine 6 is used in a tilted state, the weight 60 moves in the direction of the action of gravity inside the oil pan 24, so that the suction port of the suction part 56 is always sunk below the liquid level of the lubricating oil. Include.

  The suction port of the suction portion 56 communicates with the crank chamber 64 in which the crankshaft 40 is accommodated via the first oil feeding passage 62. A one-way valve 66 is provided in the first oil feeding passage 62. The opening communicating with the crank chamber 64 of the first oil feeding passage 62 is closed by the piston 38 while the piston 38 is lowered, and is opened when the piston 38 rises to near the top dead center. When the piston 38 rises to near the top dead center, the inside of the crank chamber 64 tends to become negative pressure, and the lubricating oil is sucked up from the oil pan 24 and supplied to the crank chamber 64. The lubricating oil introduced into the crank chamber 64 from the first oil supply passage 62 is misted into oil mist, and lubricates the crank chamber 64.

  A lower portion of the crank chamber 64 communicates with the oil pan 24 through a reed valve 75. A second oil feeding passage 72 is opened near the center of the oil pan 24, and the oil pan 24 communicates with the gear chamber 74 via the second oil feeding passage 72. The gear chamber 74 accommodates a valve drive gear 50, a cam gear 52, and the like. The gear chamber 74 communicates with the valve operating chamber 78 via the third oil feeding passage 76. The valve operating chamber 78 accommodates the rocker arm 46, the intake valve 42, the exhaust valve 44, and the like. The valve operating chamber 78 communicates with the crank chamber 64 via the fourth oil feeding passage 80. The opening communicating with the crank chamber 64 of the fourth oil feeding passage 80 is closed by the piston 38 while the piston 38 is lowered, and is opened when the piston 38 is raised to the vicinity of the top dead center. When the piston 38 descends from the top dead center toward the bottom dead center, the crank chamber 64 tends to become positive pressure, the reed valve 75 is opened, and the oil mist in the crank chamber 64 becomes the oil pan 24, the second It is sent to the gear chamber 74 through the oil feed passage 72. The oil mist sent to the gear chamber 74 is lubricated in the gear chamber 74 and then sent to the valve operating chamber 78 via the third oil feeding passage 76. The oil mist sent to the valve operating chamber 78 is lubricated in the valve operating chamber 78 and then sent to the crank chamber 64 via the fourth oil supply passage 80 when the piston 38 rises to near the top dead center. . A part of the oil mist sent from the crank chamber 64 to the oil pan 24 is liquefied and stored in the oil pan 24.

  The gear chamber 74 communicates with the crank chamber 64 through a return passage 77. The lubricating oil liquefied in the gear chamber 74 and accumulated in the gear chamber 74 is returned to the crank chamber 64 via the return passage 77 when the crank chamber 64 tends to have a negative pressure. Further, a flow rate adjusting passage 79 is provided between the gear chamber 74 and the first oil feeding passage 62. The flow rate adjusting passage 79 adjusts the flow rate of the lubricating oil flowing through the first oil feeding passage 62 by allowing air to flow between the gear chamber 74 and the first oil feeding passage 62.

  The valve operating chamber 78 communicates with the air cleaner 28 via a breather passage 82. A one-way valve 84 is provided in the breather passage 82. Air containing oil mist and blow-by gas in the valve operating chamber 78 is sent to the air cleaner 28 via the breather passage 82.

  In the air cleaner 28, the oil mist is liquefied by the oil separator 86 and the lubricating oil is separated from the air containing blow-by gas. The blow-by gas is sent to the carburetor 30 together with air. The liquefied lubricating oil is sent to the crank chamber 64 via the fifth oil feeding passage 88. A one-way valve 90 is provided in the fifth oil supply passage 88.

  An oil level sensor 98 is attached to the oil pan 24. The oil level sensor 98 is an electric resistance type level sensor. The oil level sensor 98 includes a ground electrode (not shown), an upper electrode 94 and a lower electrode 96. The oil level sensor 98 includes a state where the level of the lubricating oil is below the lower electrode 96, a state where the level of the lubricating oil is above the lower electrode 96 and below the upper electrode 94, and lubrication. A different signal is output for each of the states where the oil level is above the upper electrode 94.

  FIG. 5 shows the configuration of the oil level sensor unit 92. The oil level sensor unit 92 includes an oil level sensor 98 and a control circuit 100. Based on the signal from the oil level sensor 98, the control circuit 100 determines whether or not the level of the lubricating oil stored in the oil pan 24 is within a predetermined range. The control circuit 100 transmits an instruction regarding ignition of the spark plug 36 to the magneto circuit 48. Further, the control circuit 100 controls lighting of the warning LED 16 and sounding of the warning alarm 18 as necessary.

  When the engine 6 is started by the recoil starter 26 and electric power is generated by the magneto circuit 48, the brush cutter 2 starts the oil level inspection process shown in FIG.

  In step S <b> 102, the control circuit 100 detects the level of the lubricating oil inside the oil pan 24 by the oil level sensor 98.

  In step S104, the control circuit 100 determines whether or not the lubricant level detected by the oil level sensor 98 is within a predetermined range. If the level of the lubricating oil is within the predetermined range (in the case of YES), the oil level inspection process is terminated and the engine 6 is shifted to normal operation. When the level of the lubricating oil is not within the predetermined range (in the case of NO), the process proceeds to step S106.

  In step S106, the control circuit 100 turns on the warning LED 16 and further sounds the warning alarm 18 to notify the user of the abnormality of the lubricating oil level.

  In step S108, the magnet circuit 48 determines whether or not the engine 6 is idling. Whether or not the engine 6 is idling is determined, for example, by comparing the rotational speed of the engine 6 with a predetermined threshold value. When the engine 6 is idling (in the case of YES), the process returns to step S106 without limiting the rotational speed of the engine 6.

  In step S110, the magneto circuit 48 suppresses an increase in the rotational speed of the engine 6. While the increase in the rotational speed of the engine 6 is suppressed, even if the user performs an operation to increase the rotational speed of the engine 6 with the throttle lever, the rotational speed of the engine 6 does not increase, and noise and vibration from the engine 6 Is for low rotation. Thus, since the operation of the engine 6 is different from the user's assumption, the user can be made aware of the abnormality. After step S110, the process returns to step S106.

  The increase in the rotational speed of the engine 6 in step S110 can be suppressed by various methods. For example, by limiting the number of times of ignition by the spark plug 36 to be less than that during normal operation, an increase in the rotational speed of the engine 6 can be suppressed. Specifically, an increase in the rotational speed of the engine 6 can be suppressed by making the spark plug 36 misfire. When the rotational speed of the engine 6 is thus suppressed, the power consumed by the spark plug 36 is suppressed, and the power generated by the magnet circuit 48 can be efficiently supplied to the warning LED 16 and the warning alarm 18.

  Alternatively, the increase in the rotational speed of the engine 6 in step S110 can be suppressed by advancing or retarding the timing of ignition by the spark plug 36 relative to that during normal operation.

  In step S106, instead of notifying the user of the abnormality of the lubricant level using both the warning LED 16 and the warning alarm 18 as described above, the abnormality is notified to the user using only the warning LED 16. Alternatively, the user may be notified of the abnormality using only the warning alarm 18.

  In the brush cutter 2 of this embodiment, the level of the lubricating oil is inspected when the engine 6 is started. Normally, when the engine 6 is started, the engine 6 is kept horizontal, and therefore the oil pan 24 is kept horizontal. The oil level sensor 98 can appropriately detect the level of the lubricating oil.

  In the brush cutter 2 of this embodiment, the level of the lubricating oil is inspected only when the engine 6 is started, and the level of the lubricating oil is not inspected during the subsequent normal operation. Since there are restrictions due to fuel capacity, worker fatigue, etc., a single operation using the brush cutter 2 usually does not take several hours. For this reason, the lubricating oil does not rapidly decrease in one operation. In particular, when the engine 6 is a four-stroke cycle engine, unlike the case of the two-stroke cycle engine, the decrease in the lubricating oil in a single operation is negligible. If it is confirmed that the oil level is appropriate, it is not necessary to check the liquid level of the lubricating oil again until the end of the work. According to the brush cutter 2 of the present embodiment, the level of the lubricating oil is inspected with the minimum necessary frequency, and if the level of the lubricating oil is abnormal, the user can be surely notified.

  In the brush cutter 2 of the present embodiment, in addition to notifying the user of the presence of an abnormality using a warning device such as the warning LED 16 or the warning alarm 18 when the liquid level of the lubricating oil is not within the predetermined range, The presence of the abnormality is also notified to the user by suppressing the increase in the rotational speed of the engine 6. At the stage where the engine 6 is started and the work is started, the user does not necessarily watch the warning LED 16, and the noise from the engine 6 makes it difficult to hear the warning alarm 18, so the warning LED 16 and the warning alarm 18 are not heard. The user may not be aware of anomaly notification due to. However, if the increase in the rotational speed of the engine 6 is suppressed as described above, the noise and vibration from the engine 6 will be different from those assumed by the user of the brush cutter 2, so that the engine 6 is in a normal state. I feel that there is no. Further, since the warning LED 16 and the warning alarm 18 are notified together with the suppression of the increase in the rotational speed of the engine 6, the user operates the operation different from the assumption of the engine 6 due to the failure of the engine 6 itself. It can be known that this is due to an abnormality in the liquid level. According to the brush cutter 2 of the present embodiment, it is possible to reliably notify the user of an abnormality in the level of the lubricating oil.

  In the brush cutter 2 of the present embodiment, when the abnormality of the lubricating oil level is reported, the increase in the rotational speed of the engine 6 is suppressed, but the rotation of the engine 6 is not completely stopped. Therefore, the power for turning on the warning LED 16 and sounding the warning alarm 18 can be supplied from the magneto circuit 48. There is no need to separately provide a dedicated power source for operating the warning LED 16 and the warning alarm 18.

(Example 2)
The brush cutter 102 according to the present embodiment has substantially the same configuration as the brush cutter 2 according to the first embodiment. Below, only the point which is different from the brush cutter 2 of Example 1 is demonstrated in detail. The engine 104 of the brush cutter 102 includes an oil level sensor unit 106.

  As shown in FIG. 7, the oil level sensor unit 106 includes an oil level sensor 98, a control circuit 108, a capacitor 110, and a timer 112. The capacitor 110 is charged using the power of the magnet circuit 48 while the magnet circuit 48 is generating power. The capacitor 110 supplies power to the control circuit 108, the warning LED 16, and the warning alarm 18 after the magneto circuit 48 finishes generating the power. The timer 112 counts elapse of a predetermined time.

  When the engine 104 is started by the recoil starter 26 and electric power is generated by the magneto circuit 48, the brush cutter 102 starts the oil level inspection process shown in FIG.

  In step S 202, the control circuit 108 detects the level of the lubricating oil inside the oil pan 24 by the oil level sensor 98.

  In step S204, the control circuit 108 determines whether or not the lubricant level detected by the oil level sensor 98 is within a predetermined range. When the level of the lubricating oil is within the predetermined range (in the case of YES), the oil level inspection process is terminated and the engine 104 is shifted to normal operation. If the level of the lubricating oil is not within the predetermined range (in the case of NO), the process proceeds to step S206.

  In step S206, the control circuit 100 starts counting by the timer 112.

  In step S208, the control circuit 100 turns on the warning LED 16 to notify the user of the oil level abnormality.

  In step S210, the magnet circuit 48 determines whether or not the engine 104 is idling. If the engine 104 is idling (in the case of YES), the process proceeds to step S214 without limiting the rotational speed of the engine 104.

  In step S <b> 212, the magneto circuit 48 suppresses an increase in the rotational speed of the engine 104. Thereby, even when the user does not notice the lighting of the warning LED 16, the user can be made aware of the abnormality through the noise and vibration from the engine 104. After step S212, the process proceeds to step S214.

  In step S214, the control circuit 108 determines whether the timer 112 has finished counting. If the counting by the timer 112 has not ended (in the case of NO), the process returns to step S208. When the counting by the timer 112 is completed (in the case of YES), the process proceeds to step S216.

  In step S216, the magneto circuit 48 prohibits ignition by the spark plug 36. As a result, the rotation of the engine 104 ends.

  In step S218, the control circuit 108 sounds the warning alarm 18 to notify the user that the operation of the engine 104 has been stopped due to an abnormality in the lubricating oil level. After step S218, the oil level inspection process is terminated.

  In the brush cutter 102 of the present embodiment, when an abnormality in the liquid level of the lubricating oil is detected, first the warning LED 16 is turned on and the number of revolutions of the engine 104 is suppressed along with notification to the user. Thereafter, when a predetermined time elapses, the rotation of the engine 104 is stopped, and the user is notified by sounding the warning alarm 18. In a state where the increase in the rotational speed of the engine 104 is suppressed, the engine 104 is still rotating, and the noise from the engine 104 makes it difficult to hear the sound of the warning alarm 18. Therefore, in such a state, the warning LED 16 is turned on, but the warning alarm 18 is not sounded. Thereafter, in a state where ignition of the spark plug 36 is prohibited in order to stop the rotation of the engine 104, the noise from the engine 104 is reduced, so that notification by the sounding of the warning alarm 18 is performed again. With such a configuration, it is possible to reliably notify the user of an abnormality in the level of the lubricating oil.

  In this embodiment, the power generated by the magnet circuit 48 is charged in the capacitor 110, and after the ignition of the spark plug 36 is prohibited, the power is supplied from the capacitor 110 to the warning alarm 18. With such a configuration, it is possible to reliably supply power to the warning alarm 18. Even in the case where the capacitor 110 is not provided, since a certain amount of time is required until the rotation of the crankshaft 40 is completely stopped after the ignition of the spark plug 36 is prohibited, the magneto circuit 48 is generated during that time. It is also possible to notify the abnormality by the warning alarm 18 using the power to be used.

(Example 3)
The brush cutter 202 according to the present embodiment has substantially the same configuration as the brush cutter 2 according to the first embodiment. Below, only the point which is different from the brush cutter 2 of Example 1 is demonstrated in detail. The engine 204 of the brush cutter 202 includes an oil level sensor unit 206.

  As shown in FIG. 9, the oil level sensor unit 206 includes an oil level sensor 98, a control circuit 208, and a tilt sensor 210. The tilt sensor 210 can detect the tilt angle of the oil pan 24 from the horizontal level, that is, the tilt angle of the engine 204 from the horizontal level.

  When the engine 204 is started by the recoil starter 26 and electric power is generated by the magneto circuit 48, the brush cutter 202 starts the oil level inspection process shown in FIG.

  In step S <b> 302, the control circuit 208 detects the tilt angle of the oil pan 24 by the tilt sensor 210.

  In step S304, it is determined whether or not the oil pan 24 is kept horizontal. Specifically, it is determined whether or not the inclination angle of the oil pan 24 is within a predetermined range. If the oil pan 24 is not kept horizontal (in the case of NO), the process proceeds to step S306.

  In step S306, the control circuit 208 turns on the warning LED 16 and further sounds the warning alarm 18 to notify the user of the abnormal posture of the oil pan 24.

  In step S308, the magnet circuit 48 determines whether or not the engine 204 is idling. If the engine 204 is idling (in the case of YES), the process returns to step S302 without limiting the number of revolutions of the engine 204.

  In step S <b> 310, the magneto circuit 48 suppresses an increase in the rotational speed of the engine 204. Thereby, even when the user does not notice the lighting of the warning LED 16 or the ringing of the warning alarm 18, the user can be notified of the abnormality through the noise and vibration from the engine 204. After step S310, the process returns to step S302.

  If the oil pan 24 is kept horizontal in step S304 (in the case of YES), the process proceeds to step S312. In step S <b> 312, the control circuit 208 detects the level of the lubricating oil inside the oil pan 24 by the oil level sensor 98.

  In step S314, the control circuit 208 determines whether or not the lubricating oil level detected by the oil level sensor 98 is within a predetermined range. If the level of the lubricating oil is within the predetermined range (in the case of YES), the lighting of the warning LED 16 and the ringing of the warning alarm 18 are stopped in step S322, and the engine 204 is shifted to normal operation. If it is determined in step S314 that the level of the lubricating oil is not within the predetermined range (in the case of NO), the process proceeds to step S316.

  In step S316, the control circuit 208 turns on the warning LED 16 and further sounds the warning alarm 18 to notify the user of the abnormality of the lubricating oil level.

  In step S318, the magnet circuit 48 determines whether or not the engine 204 is idling. If the engine 204 is idling (in the case of YES), the process returns to step S316 without limiting the number of revolutions of the engine 204.

  In step S320, the magnet circuit 48 suppresses the rotational speed of the engine 204. Thereby, even when the user does not notice the lighting of the warning LED 16 or the ringing of the warning alarm 18, the user can be notified of the abnormality through the noise and vibration from the engine 204. After step S320, the process returns to step S316.

  In the brush cutter 202 of the present embodiment, the engine 204 is kept horizontal when the engine 204 is started, and only when the level of the lubricating oil in the oil pan 24 is within a predetermined range. In other cases, the engine 204 is switched to the normal operation, and in addition to the notification using the warning LED 16 and the warning alarm 18, the rotational speed of the engine 204 is suppressed. Accordingly, even when the engine 204 is not kept horizontal when the engine 204 is started and therefore the oil level sensor 98 cannot properly detect the liquid level of the lubricating oil, the user can be notified of the abnormality. In this case, if the engine 204 is returned to the horizontal state and it is determined that the level of the lubricating oil is normal in that state, the engine 204 can be shifted to normal operation.

  Even in the brush cutter 202 of the present embodiment, in step S310, instead of notifying the user of the abnormality using both the warning LED 16 and the warning alarm 18 as described above, only the warning LED 16 is used to notify the user of the abnormality. Or the user may be notified of the abnormality using only the warning alarm 18.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

  For example, the brush cutter 102 of the second embodiment can be combined with the tilt sensor 210 of the third embodiment so that the level of the oil pan 24 is ensured when the level of the lubricating oil is inspected.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and achieving one of the objects itself has technical utility.

2, 102, 202 Brush cutter; 4 Operating rod; 6, 104, 204 Engine; 8 Gear head; 10 Cutting blade; 12 Safety cover; 14 Handle; 16 Warning LED; 18 Warning alarm; 20 Engine body; 24 Oil pan; 26 Recoil starter; 28 Air cleaner; 30 Carburetor; 32 Muffler; 34 Combustion chamber; 36 Spark plug; 38 Piston; 40 Crankshaft; 42 Intake valve; 44 Exhaust valve; 46 Rocker arm; 48 Magneto circuit; Drive gear; 52 Cam gear; 54 Push rod; 56 Suction part; 58 Tube; 60 Weight; 62 First oil supply passage; 64 Crank chamber; 66 One-way valve; 72 Second oil supply passage; 74 Gear chamber; 76 Third oil feed passage; 77 Return passage; 7 8 valve chamber; 79 flow rate adjusting passage; 80 fourth oil feeding passage; 82 breather passage; 84 one-way valve; 86 oil separator; 88 fifth oil feeding passage; 90 one-way valve; 92, 106, 206 oil level sensor Unit: 94 Upper electrode; 96 Lower electrode; 98 Oil level sensor; 100, 108, 208 Control circuit; 110 Capacitor; 112 Timer; 210 Tilt sensor

Claims (4)

A portable work machine equipped with an internal combustion engine having a lubricating oil tank,
An oil level sensor for detecting a level of lubricating oil stored in the lubricating oil tank;
A rotation speed adjustment device capable of adjusting the rotation speed of the internal combustion engine;
A first warning device for notifying the user of an abnormality in the level of the lubricating oil;
Between the start of the internal combustion engine and the start of work by the user, the liquid level of the lubricating oil stored in the lubricating oil tank is automatically inspected,
When the detected value of the oil level sensor does not fall within a predetermined range during the inspection of the level of the lubricating oil, the first warning device notifies the user of the abnormality, and the rotation speed adjusting device A portable working machine that suppresses an increase in the rotational speed of the internal combustion engine. An operation stop device for stopping the operation of the internal combustion engine;
A second warning device for notifying the user of abnormality in the level of the lubricating oil;
When a predetermined time has elapsed since the start of the abnormality notification by the first warning device, the operation of the internal combustion engine is stopped by the operation stop device, and the abnormality is notified to the user by the second warning device. The portable work machine according to claim 1, wherein: An inclination sensor for detecting an inclination angle of the lubricating oil tank;
If the detected value of the tilt sensor does not fall within a predetermined range before the inspection of the liquid level of the lubricating oil, the first warning device will continue until the detected value of the tilt sensor falls within the predetermined range. The portable work machine according to claim 1, wherein an abnormality notification to the user is performed and an increase in the rotational speed of the internal combustion engine is suppressed by the rotational speed adjustment device.   4. The engine according to claim 1, wherein the rotation speed adjustment device suppresses the rotation speed of the internal combustion engine from that in a normal state by reducing the number of ignitions of the ignition device in the internal combustion engine from that in a normal time. The portable work machine according to any one of the items.

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