JP2013151863A - Engine working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine working machine in which startability is improved by employing a low-voltage battery.SOLUTION: The machine includes a battery 80, a booster (130) which raises a voltage supplied from the battery 80, a temperature detection means (119) for detecting a temperature, and a solenoid valve 104 for additionally injecting fuel in a cylinder of an engine 10. When the temperature detected by the temperature detection means (119) is not higher than a prescribed value, the solenoid valve 104 is driven by the voltage boosted by the booster (130) to additionally inject fuel in the cylinder. The action of the solenoid valve 104 is executed by a control means having a microcomputer 118.

Description

  The present invention relates to a portable engine work machine such as a chain saw or a brush cutter, and more particularly to an engine work machine provided with a starter that is driven using a small battery.

  In small working machines such as brush cutters and chain saws, small engines are widely used as power sources. FIG. 7 is an external view of a brush cutter as an example of a conventional engine working machine 101. As shown in FIG. 7, an engine work machine 101 equipped with a small two-cycle engine passes a drive shaft (not shown) through a pipe-shaped main pipe 5, and this drive shaft is connected to an engine provided at one end of the main pipe 5. The rotary blade 6 provided at the other end of the main pipe 5 is rotated. In the vicinity of the rotary blade 6, a scattering protection cover 6 a for preventing scattering of the cut grass is provided. The engine work machine 101 is carried by a shoulder strap or the like (not shown), and a handle 4 having a substantially U shape in front view for operation by an operator is attached to the vicinity of the longitudinal center of the main pipe 5. The number of revolutions of the engine is controlled by an operator by a throttle lever (not shown) attached to the grip portion 3. The operation of the throttle lever is transmitted to the carburetor of the engine through the wire 37.

  An engine such as that used in the engine work machine 101 is small and light and can provide a large output, and can be operated for a long time by supplying fuel. In the engine work machine 101, a manual starter is used to start the engine, and various ideas for improving the startability have been proposed. For example, Patent Document 1 proposes an engine work machine in which a battery and a cell motor are built in and startability is improved by the cell motor.

Japanese Patent No. 3400191

  In the engine working machine of Patent Document 1, related equipment (solenoid valve etc.) that matches the battery voltage specification must be used. When using 1-cell or 2-cell lithium batteries for the purpose of weight reduction, comparison is required. There is a problem that a solenoid valve for 12V drive with high general versatility cannot be used as it is.

  The present invention has been made in view of the above background, and an object thereof is to provide an engine working machine capable of reducing the size and weight of a battery in a starter using a battery and a solenoid valve.

  Another object of the present invention is to provide an engine working machine having improved startability by electronically controlling a choke mechanism at the start of a cell motor.

  Still another object of the present invention is to provide an engine working machine having a lightweight and inexpensive starting device.

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

  According to one aspect of the present invention, in a portable engine work machine driven by an engine, a small battery, boosting means for boosting a voltage supplied from the battery, and additional fuel for injecting fuel into the engine A solenoid valve for opening and closing the fuel supply path is provided, and the solenoid valve is driven by the voltage boosted by the boosting means so that fuel is additionally supplied into the cylinder of the engine when the engine is started. Further, a temperature detecting means for detecting the temperature is provided, and the solenoid valve is driven only when the temperature detected by the temperature detecting means is less than a predetermined value. Since the boosting means is used in this way, the output voltage of the battery is set lower than the operating voltage of the solenoid valve.

  According to another aspect of the invention, the battery is a cassette type (or battery pack type) that is detachable from the engine working machine. Although various types of batteries are conceivable, lithium ion secondary batteries are preferable. The boosting means includes a booster circuit, charges the electric double layer capacitor with the voltage boosted by the booster circuit, and drives the solenoid valve.

  According to still another feature of the present invention, a control means for driving the solenoid valve is provided, and when the switch means for starting the engine is turned on, electric power is supplied from the battery to the control means to operate the control means. The control means performs control so as not to supply power to the solenoid valve when the temperature detected by the temperature detection means is equal to or higher than a predetermined value. Further, a cell motor that is driven by the electric power supplied from the boosting means to start the engine is provided, and the control means is configured to start the engine by performing control of the solenoid valve and rotation control of the cell motor.

  According to the invention of claim 1, since the solenoid valve is driven by boosting the voltage supplied from the battery, it is possible to use a relatively versatile solenoid valve called a solenoid valve having a high rated voltage. it can.

  According to the invention of claim 2, since the temperature detection means for detecting the temperature is used for control, the solenoid valve is driven when it is not necessary to supply additional fuel into the cylinder when the engine is sufficiently warm. Can be stopped.

  According to the invention of claim 3, since the output voltage of the battery is lower than the operating voltage of the solenoid valve, a 1-cell and 2-cell lithium ion secondary battery can be used, and the engine working machine can be reduced in size and weight. realizable.

  According to the invention of claim 4, since the battery is a cassette system that can be attached to and detached from the engine working machine, the battery can be removed and charged, and when the battery is consumed, it can be easily replaced with a charged battery. Therefore, it is possible to provide a user-friendly engine working machine.

  According to the invention of claim 5, since the battery is a lithium ion secondary battery, a battery having a small memory effect and a high energy density can be realized.

  According to the sixth aspect of the present invention, since the electric double layer capacitor is charged with the voltage boosted by the boosting means and the solenoid valve is driven, the solenoid valve having a driving current larger than the rated output current of the boosting means is stabilized. Can be driven.

  According to the seventh aspect of the present invention, the control means for driving the solenoid valve is provided, and the control means operates only when the switch means for starting the engine is turned on. Therefore, when the engine is stopped during storage or the like. In addition, the battery can be prevented from being consumed by the control means.

  According to the invention of claim 8, since the control means does not supply power to the solenoid valve when the temperature detected by the temperature detection means is equal to or higher than a predetermined value, it is added when the outside air temperature is high or the engine is warm. Fuel can be prevented from being supplied, and engine fogging and the like can be prevented.

  According to the ninth aspect of the present invention, since the cell motor that is driven by the electric power supplied from the booster and starts the engine is provided, the engine can be started without using a manual starter. Moreover, since a cell motor can be started with a low voltage battery, it can suppress that a battery enlarges for cell motors.

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

It is a longitudinal section showing the internal structure of engine working machine 1 concerning the example of the present invention. It is a rear view of the engine working machine 1 which concerns on the Example of this invention. 1 is a circuit diagram of an engine work machine 1 according to an embodiment of the present invention. It is a flowchart which shows the starting procedure of the engine working machine 1 which concerns on the Example of this invention. It is a circuit diagram of the engine working machine which concerns on 2nd Example of this invention. It is a flowchart which shows the starting procedure of the engine working machine which concerns on 2nd Example of this invention. It is a perspective view which shows an example (brusher) of the conventional engine working machine.

  Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same portions are denoted by the same reference numerals, and repeated description is omitted. Further, in this specification, description will be made assuming that the front, rear, left, right, and up and down directions are directions shown in the drawing.

  FIG. 1 is a longitudinal sectional view showing the internal structure of the engine working machine 1 according to this embodiment. The engine 10 is a two-cycle small engine, the crankshaft 13 is arranged coaxially with the main pipe 5 (see FIG. 7), the cylinder 11 is arranged so as to extend from the crankcase 14 substantially upward in the vertical direction, The piston 12 reciprocates in the cylinder 11 in the vertical direction. One end of a drive shaft (not shown) is connected to the front side (output side) of the crankshaft 13 via a clutch shaft 32 via a centrifugal clutch 29. The magnet rotor 22 to which the centrifugal clutch 29 is attached is integrally formed with engine cooling fins. The centrifugal clutch 29 is a known centrifugal clutch in which the oscillator 30a is connected to the clutch drum 30b by centrifugal force when the rotation speed of the crankshaft 13 becomes equal to or higher than a certain value. The clutch shaft 32 is rotatably held by a bearing 33 held by a housing 34.

  An ignition coil 23 is provided on the outer peripheral portion of the magnet rotor 22, here in the upper portion. The high-voltage current generated by the ignition coil 23 is transmitted to the spark plug 25 through the ignition cord 24 and the plug cap 25a. A fuel tank 27 is provided below the crankcase 14 of the engine 10. The fuel tank 27 contains a mixed oil of gasoline and oil for two cycles, and is sent to a vaporizer 35 described later.

  A recoil starter 40 is provided as the starting device of the present embodiment. The recoil starter 40 is a starting device for starting the engine that has stopped rotating, and the starter rope 42 wound around the reel 41 is wound by an operator pulling a starter handle 36 (described later). The reel 41 is released and rotated at a high speed. As the reel 41 rotates, the one-way clutch 46 protrudes radially outward by centrifugal force, and the drum 47 is rotated in close contact with the drum 47. Since the drum 47 is fixed to the crankshaft 13, rotation of the drum 47 means rotation of the crankshaft 13, and the piston 12 can also reciprocate to start the engine. The released starter rope 42 is wound around the reel 41 by the restoring force of the spiral spring 43.

  Electric power is supplied to the engine 10 from the battery accommodating portion 39 to the solenoid through the power line 52. The battery accommodating portion 39 is provided separately from, for example, the two grip portions 3 (see FIG. 7) held by the operator, and is detachably provided on the handle 4, for example. When starting the engine 10, the stop switch 38 (described later) is set to “operation”, the switch 110 is turned on, and then the recoil starter 36 (described later) is pulled. When stopping the engine 10 during operation, a stop switch 38 (described later) is switched from “operation” to “stop”. A battery 80 that is substantially cylindrical and can be attached and detached is housed inside the battery housing portion 39. The battery 80 has a substantially cylindrical shape and is configured in a so-called cassette type so that it can be attached to and detached from the battery housing 39. The battery 80 has two hook portions 81 a formed therein, and holds the battery 80 by engaging with a recess (not shown) formed on the inner wall of the battery housing portion 39. To remove the battery 80, the battery 80 is pulled out from the battery housing portion 39 while pressing the release button 81.

  For example, one 14500-size lithium ion battery cell (not shown) is accommodated in the battery 80. The shape of the rear end portion (lower side in the drawing) of the battery 80 is formed so as to cover the opening 39 a at the lower end of the battery housing portion 39. A terminal base 85 is provided at the other end of the mounting space of the battery 80 following the opening 39a, and a plurality of terminals 84 are provided so as to extend from the terminal base 85 toward the opening 39a. A plurality of terminals 83 are provided at the front end portion (upper side in the figure) of the battery 80, and the terminal 83 comes into contact with the terminal 84 formed on the battery housing portion 39 side by attaching the battery 80 to the battery housing portion 39. Therefore, the power of the battery 80 is supplied to the control circuit 102 described later by turning the terminal 84.

  FIG. 2 is a rear view of the engine working machine 1 according to the embodiment of the present invention. A carburetor 35 is provided on the left side of the engine 10 via an insulator 19 that connects an intake port of the engine 10, and an air cleaner cover 26 that forms a storage space for an air cleaner that filters inhaled air on the left side of the carburetor 35. Is provided. A muffler 16 is provided on the right side of the engine 10, and an exhaust port 16 a serving as an exhaust gas outlet is provided on the rear surface side of the muffler 16. The muffler 16 is covered with a resin muffler cover 8 to prevent the operator from touching it directly. The upper portion of the engine 10 is covered by the upper cover 7. A recoil starter 40 (see FIG. 1) is provided coaxially with the crankshaft 13 and at the rear end thereof, and the recoil starter 40 is covered with a starter case 9. A starter handle 36 is provided on the left side of the starter case 9. A fuel tank 27 is provided below the crankcase 14. The fuel tank 27 is a container formed of a translucent polymer resin, and a mixed fuel in which gasoline and a predetermined ratio of oil are mixed can be put in by removing the cap 28 attached to the opening.

  FIG. 3 is a circuit diagram of the engine working machine 1 according to the present embodiment. The engine working machine 1 is provided with a starting device using a solenoid valve 104, and the starting device is electronically controlled by a control circuit 102 (control means). The solenoid valve 104 functions as an auto choke at the time of starting, and opens and closes a fuel supply path (not shown) for additionally injecting fuel into the engine. A location where the solenoid valve 104 is attached is not shown, but may be provided between the cylinder 11 and the vaporizer 35, for example. The control circuit 102 includes four FETs (Field Effect Transistors) 107, 117, 122, 133, resistors 108, 109, 111, 112, 120, 136, 137, a switch 110, capacitors 113, 114, 115, 135, a regulator 116, a microcomputer 118, a thermistor 119, an inductor 132, and a diode 134.

  The microcomputer 118 is driven by a constant voltage supplied by the regulator 116, and a plurality of A / D conversion ports have an output signal of the thermistor 119 indicating the engine temperature, and a signal indicating the voltage of the battery 80 by the resistors 112 and 114. The output signal of the rotation detection coil 105 is input. The engine rotation signal is detected by converting magnetic flux from a magnet attached to the engine 10 into a voltage by the rotation detection coil 105 and inputting the voltage to the microcomputer 118. The microcomputer 118 performs a predetermined logical operation from these input values and sends out gate signals of the FETs 117, 122, and 133, thereby controlling conduction or blocking between the source and drain of the FETs 117, 122, and 133.

  The FET 122 serves as a switch for opening the solenoid valve 104, and the source and drain of the FET 122 are brought into conduction by a command from the microcomputer 118 (supply of a gate signal), and the solenoid valve 104 is opened. The solenoid valve 104 is provided in the vicinity of the carburetor. When the solenoid valve 104 is opened at the time of starting, rich fuel is supplied to the inside of the cylinder of the engine 10 so that the startability can be improved.

  The step-up circuit 130 is a step-up chopper circuit including an inductor 132, an FET 133, a diode 134, a capacitor 135, and resistors 136 and 137. The step-up operation is performed by switching the FET 133 by the microcomputer 118. At the same time, the voltage divided by the resistors 136 and 137 is input to the A / D conversion input terminal of the microcomputer 118 to monitor the boosted voltage, and by controlling the switching ON duty of the FET 133, the boosted voltage is always set to the solenoid valve 104. Feedback control is performed so that the voltage is the same as the voltage specification. By using the booster circuit 130, a necessary voltage for driving the 12V solenoid valve 104 from the 3.6V battery 80 can be obtained.

  Next, a series of operations of the engine work machine 1 of the present invention will be described with reference to the flowchart of FIG. First, when the starter switch 110 is turned on (step 201), the gate voltage of the FET 107 is applied by the resistors 108 and 109, the FET 107 is turned on (step 202), and the voltage is supplied to the regulator 116. The The regulator 116 is a constant voltage source for supplying a constant voltage to the microcomputer 118 and the like. The capacitors 114 and 115 are for stabilizing the output voltage of the regulator 116.

  When a predetermined voltage is input to the power supply terminal of the microcomputer 118, the microcomputer 118 is activated (step 203). Next, the microcomputer 118 supplies the gate signal to turn on the FET 117 (conduction between the source and drain), and keeps the FET 107 on even after the switch 110 is opened (step 204).

  Next, the microcomputer 118 measures the battery voltage (step 205). In this embodiment, the battery 80 is one lithium ion battery with a rated voltage of 3.6V. The battery voltage is measured by smoothing the voltage divided by the resistors 111 and 112 with the capacitor 113 and inputting it to the A / D conversion input terminal of the microcomputer 118. Here, it is determined whether the battery voltage is 3.0 V or less. This 3.0V is a threshold voltage value for determining whether or not the battery of this embodiment can be used. If the detected battery voltage is 3.0V or less, it is determined that the battery is in an overdischarged state. In step 213, the FET 117 is turned OFF, and the power supply of the microcomputer 118 is shut down. On the other hand, when the detected battery voltage is 3.0 V or more, the routine proceeds to step 206. The voltage value serving as the threshold used in step 205 is not limited to 3.0 V, and an optimal value may be set as appropriate in consideration of the internal resistance, capacity and characteristics of the battery 80, capacity and characteristics of the cell motor, circuit resistance, and the like. .

  In step 206, the microcomputer 118 detects the temperature from the output signal of the thermistor 119. This temperature detection is performed by inputting the voltage divided by the thermistor 119 and the resistor 120 to the A / D conversion input terminal of the microcomputer 118. If the measured temperature is equal to or higher than a predetermined value (for example, 20 ° C.), the microcomputer 118 proceeds to step 213. This is because if the temperature is 20 ° C. or higher, additional fuel injection by the solenoid valve 104 is not necessary, and conversely, if additional fuel is injected, fogging may occur. If the measured temperature is less than a predetermined value (for example, 20 ° C.), the booster circuit 130 is activated to prepare for supplying a direct current equal to or higher than the voltage supplied from the battery 80 to the solenoid valve 104. The microcomputer 118 detects whether or not the rotation signal of the engine 10 is detected (step 208), and waits until it is detected. The rotation signal of the engine 10 can be detected by the output of the rotation detection coil 105.

  When the user pulls the starter handle 36 (see FIG. 2), the engine 10 rotates, and an engine rotation signal is generated in the rotation detection coil 105 every rotation. When the engine rotation signal is detected, the microcomputer 118 proceeds to step 209 to turn on the FET 122 for a predetermined time and energize the solenoid valve 104, thereby closing the additional fuel supply unit (not shown) closed by the solenoid valve. To make additional fuel injection.

  Next, in step 210, it is determined whether the solenoid valve 104 has been turned ON a predetermined number (for example, 10 times). If it has not reached 10 times, the process returns to step 208 and waits for the next engine rotation signal. Steps 208 to 210 are repeated, and the process proceeds to step 211 when the number reaches 10 times. In step 210, it is determined whether the number of times of opening and closing has reached 10. However, the number of times is not limited to 10 and may be appropriately set according to the characteristics of the engine.

  In step 211, it is determined whether or not the engine has started. This can be determined based on whether or not the engine rotation signal is periodically detected by the microcomputer 118. If the engine is not running, the process proceeds to step 212, the count value for measuring the number of times the solenoid valve is turned on is reset to 0, and the process returns to step 208 again. If the microcomputer 118 determines in step 211 that the engine has started, the process proceeds to step 213, where the microcomputer 118 turns off the FET 117 and shuts down the power supply of the control circuit 102 itself.

  As described above, according to the embodiment of the present invention, when the rotation signal of the engine 10 is detected, the microcomputer 118 turns on the solenoid valve 104 to open or close more fuel than the amount supplied from the normal carburetor to the engine 10. In addition, the solenoid valve 104 is turned on to perform additional injection into the cylinder. The solenoid valve 104 is a general-purpose product with a low component cost for 12V, and is driven by a low voltage battery using a booster circuit. As a result, an electronically controlled starting device (solenoid valve and control circuit) that improves starting performance can be driven by a low-voltage small battery such as one lithium ion battery. Can be realized.

  In the above-described embodiment, the engine 10 is started using the recoil starter 40. However, the present invention can be similarly applied not only to the recoil starter 40 but also to an engine working machine provided with a cell motor. FIG. 5 is a circuit diagram of an engine work machine according to a second embodiment of the present invention. In the circuit diagram shown in FIG. 3, the same components as those in the first circuit diagram are denoted by the same reference numerals, and the repetitive description will be omitted. 5 is different from the first embodiment in that a cell motor 106 controlled through the FET 121 is added. In addition, a cell switch 125 and a resistor 124 for starting the cell motor 106 are added. The microcomputer 118 further receives a terminal voltage of the resistor 124 for detecting the open / closed state of the cell switch 125.

  Although it is conceivable that the cell motor 106 is driven by the voltage of the battery 80 without boosting, the cell motor 106 is driven by the voltage boosted by the boosting circuit 130 in this embodiment. If comprised in this way, the cell motor 106 for 6V or 12V can be driven with low voltage small batteries, such as one lithium ion battery. One of the cell switches 125 is installed on the ground, and the other is connected to the A / D port of the microcomputer 118. The A / D port is further connected to the drain of the FET 107 via the resistor 124. When the cell switch 125 is turned on, the A / D port of the microcomputer 118 is installed. It can be detected that it is turned on.

  FIG. 6 is a flowchart showing a starting procedure of the engine working machine in the second embodiment. The basic control procedure is the same as the control procedure in the first embodiment shown in FIG. 4, and the same reference numerals are given to the same steps as the control procedure, except that the cell motor 106 is driven. In order to do this, step 401 and step 402 are added. If it is confirmed in step 205 that the battery voltage is 3.0 V or more, the microcomputer 118 determines in step 401 whether the cell switch 125 is pressed (turned on). Here, if the cell switch 125 remains OFF, it waits until it is turned ON. When the cell switch 125 is turned on, the microcomputer 118 turns on the FET 121 to supply a predetermined direct current to the cell motor 106 to rotate the cell motor 106 (step 402). The control after the rotation of the cell motor 106 is started, that is, the control in steps 206 to 214 is the same as that in the first embodiment.

  As described above, in the second embodiment, the battery 80 is used to drive both the solenoid valve 104 and the cell motor 106. In addition, since the voltage boosted by the booster circuit 130 is used for them, the battery 80 having a lower output voltage than the operable voltage of the cell motor 106 and the solenoid valve 104 can be used, thereby reducing the number of cells of the battery 80. It is possible to achieve small size and light weight.

  As mentioned above, although this invention was demonstrated based on the Example, this invention is not limited to the above-mentioned Example, A various change is possible within the range which does not deviate from the meaning. For example, although the above-described engine working machine has been described as a brush cutter, the engine working machine is not limited to a brush cutter, but may be other engine working machines such as a cutter, a chain saw, and a lawn mower.

DESCRIPTION OF SYMBOLS 1 Engine working machine 2 Main-body part 3 Grip part 4 Handle 5 Main pipe 6 Rotary blade 6a Spattering prevention cover 7 Upper cover
8 Muffler cover 9 Starter case 10 Engine 11 Cylinder 12 Piston 13 Crankshaft 14 Crankcase 16 Muffler 16a Exhaust port 19 Insulator 22 Magnet rotor 23 Ignition coil 24 Ignition cord 25 Spark plug 25a Plug cap 26 Air cleaner cover 27 Fuel tank 28 Cap 29 Centrifugal Clutch 30a Oscillator 30b Clutch drum 31 Decompression 32 Clutch shaft 33 Bearing 34 Housing 35 Vaporizer 36 Starter handle 37 Wire 38 Stop switch 39 Battery accommodating part 39a Opening 40 Recoil starter 41 Reel 42 Starter rope 43 Spiral spring 46 One-way clutch 47 Drum 52 Power line 80 Battery 81 Lily Button 81a hooking portion 83 terminal 84 terminal 85 terminal base 102 control circuit 104 solenoid valve 105 rotation detecting coil 106 starter motor 107,117,121,122,123,133 FET
108, 109, 111, 112, 120, 124, 136, 137 Resistor 110 Switch 113, 114, 115, 135 Capacitor 116 Regulator 118 Microcomputer 119 Thermistor 125 Cell switch 130 Boost circuit 132 Inductor 134 Diode

Claims (9)

An engine working machine driven by an engine,
Battery,
Boosting means for boosting the voltage supplied from the battery;
A solenoid valve for additionally injecting fuel into the engine is provided, the solenoid valve is driven by a voltage boosted by the boosting means, and fuel is additionally supplied into the cylinder of the engine when the engine is started. Engine working machine.   The engine working machine according to claim 1, wherein temperature detecting means for detecting temperature is provided, and the solenoid valve is driven when the temperature detected by the temperature detecting means is less than a predetermined value.   The engine working machine according to claim 1 or 2, wherein an output voltage of the battery is lower than an operating voltage of the solenoid valve.   The engine work machine according to any one of claims 1 to 3, wherein the battery is of a cassette type that is detachable from the engine work machine.   The engine working machine according to any one of claims 1 to 4, wherein the battery is a lithium ion secondary battery.   6. The engine working machine according to claim 5, wherein the boosting means includes a boosting circuit, and the capacitor is charged with a voltage boosted by the boosting circuit to drive the solenoid valve. Providing a control means for driving the solenoid valve;
The engine according to any one of claims 1 to 6, wherein when the switch means for starting the engine is turned on, electric power is supplied from the battery to the control means to operate the control means. Work machine.   The engine work machine according to claim 7, wherein the control means does not supply power to the solenoid valve when the temperature detected by the temperature detection means is equal to or higher than a predetermined value. A cell motor that is driven by the electric power supplied from the booster and starts the engine is provided,
9. The engine working machine according to claim 8, wherein the control unit starts the engine by performing control of the solenoid valve and rotation control of the cell motor.

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