JP2010077943A - Non-loaded condition detection method and device for general-purpose internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the non-loaded condition detection method and device for a general-purpose internal combustion engine configured so as to determine non-loaded conditions with high degree of accuracy by setting a threshold value near the throttle opening degree taken at the stable rotation performed in a steady operation region to compare the throttle opening degree to the set threshold value. <P>SOLUTION: The device includes an electronic governor for controlling the rotation number of an engine via an actuator which actuates a throttle valve disposed on an air intake path, determines whether the rotation number of the engine converges to a target rotation number determined based on a load in a general-purpose internal combustion engine coupled with a load and outputting power (S10), sets a threshold value to a value obtained by adding a predetermined value to the throttle opening degree detected when the rotation number of the engine converges to the target value (S12, S14), counts the number of times C when the throttle opening degree detected is less than the threshold value (S16, S18), and determines the engine to be under non-loaded conditions under which the load consumes no power (S20, S22), when the number of times C exceeds a prescribed value n. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a no-load detection method and apparatus for a general-purpose internal combustion engine.

  A general-purpose internal combustion engine is usually connected to a load such as a work machine and outputs power, but if the load is in a no-load state that does not consume that power, leaving it unattended is not preferable in terms of noise and fuel consumption. Like the technique described in Patent Document 1, a no-load state is detected to reduce the engine speed.

In the technique described in Patent Document 1, the internal combustion engine is connected to a pump of a high-pressure washing machine, and the pump is driven to discharge water from the washing gun. The presence or absence of water discharge work, that is, the no-load state of the pump, is determined by comparing the detected throttle opening with a throttle opening (threshold) that is set to increase as the engine speed increases. Is done.
JP 2005-299519 A

  In the technique described in Patent Document 1, a value determined from the engine speed is used as a threshold value with which the throttle opening is compared. However, the threshold value takes into account changes due to the operating state and environment of the internal combustion engine. In such a case, it may be determined that there is no load even when a small load is applied.

  Therefore, the object of the present invention is to solve the above-mentioned problems, and by setting a threshold value near the throttle opening when rotating stably in the steady operation region and comparing it with the throttle opening, no load is applied. It is an object of the present invention to provide a no-load detection method and apparatus for a general-purpose internal combustion engine that accurately determines the state.

  In order to solve the above-described object, according to the first aspect of the present invention, an electronic governor that adjusts the engine speed via an actuator that drives a throttle valve disposed in an intake passage is provided, and is connected to a load for power. In the general-purpose internal combustion engine that outputs the throttle valve, the throttle opening degree detecting means for detecting the opening degree of the throttle valve, the engine speed detecting means for detecting the engine speed, and the detected engine speed according to the load Target rotational speed convergence determining means for determining whether or not the target rotational speed is determined, and when the detected engine rotational speed is determined to have converged to the target rotational speed, the detected Threshold setting means for setting a threshold to a value obtained by adding a predetermined value to the throttle valve opening, and the detected throttle valve opening is less than the threshold When counting means for counting the number of said counted number exceeds a prescribed value, the load is as constituting and a no-load condition determining means for determining that there is a no load condition does not consume power.

  According to a second aspect of the present invention, there is provided a general-purpose internal combustion engine that includes an electronic governor that adjusts the engine speed via an actuator that drives a throttle valve disposed in an intake passage, and that outputs power by being connected to a load. It is determined whether or not the determined engine speed has converged to a target speed determined according to the load, and when it is determined that the detected engine speed has converged to the target speed, A threshold is set to a value obtained by adding a predetermined value to the detected opening of the throttle valve, the number of times that the detected opening of the throttle valve is less than the threshold is counted, and the counted number of times When the load exceeds a specified value, the load is determined to be in a no-load state in which no power is consumed.

  In the no-load detection device for a general-purpose internal combustion engine according to claim 1, it is determined whether or not the detected engine speed has converged to a target speed determined in accordance with the load, and has converged. When the determination is made, a threshold is set to a value obtained by adding a predetermined value to the detected throttle valve opening, and the number of times the detected throttle opening is less than the threshold is counted and counted. When the number of times exceeds the specified value, it is determined that the load is in a no-load state that does not consume power, that is, the throttle opening when the vehicle is rotating stably in the steady operation region is found, Since the threshold value is set at a position above the predetermined value, and when the detected value falls below the threshold value, the number of times exceeds the specified value, it is determined to be in the no-load state. Can be set properly and no load is applied. It can be accurately determined.

  In addition, when the number of times the detected throttle valve opening is less than the threshold value exceeds a specified value, it is determined that the throttle valve is in a no-load state by appropriately setting a predetermined value, thereby reducing a small load. The added state is not determined as a no-load state.

  The same applies to the no-load detection method according to claim 2.

  The best mode for carrying out the no-load detection method and apparatus for a general-purpose internal combustion engine according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a schematic view generally showing a no-load detection apparatus for a general-purpose internal combustion engine according to an 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 and uses gasoline as fuel, and has an exhaust amount of about 440 cc, for example.

  A single piston 14 is accommodated in a cylinder (cylinder) formed inside the cylinder block 12 of the engine 10 so as to be capable of reciprocating. A cylinder head 16 is attached to an upper portion of the cylinder block 12, and a combustion chamber 18 formed at a position facing the top of the piston 14, and an intake port 20 and an exhaust port 22 communicating with the combustion chamber 18 are provided. . An intake valve 24 is provided near the intake port 20, and an exhaust valve 26 is provided near the exhaust port 22.

  A crankcase 30 is attached to the lower part of the cylinder block 12, and a crankshaft 32 is rotatably accommodated therein. The crankshaft 32 is connected to the lower part of the piston 14 via a connecting rod 34. A load 36 is connected to one end of the crankshaft 32, and the engine 10 outputs power to the load 36.

  The load means “the mechanical equipment that consumes energy (output) from the prime mover or the magnitude of the power (working rate) consumed by the mechanical equipment”. In this specification, the load 36 is the former, specifically, Used to mean a work machine (snowblower, high pressure washer, etc.). Further, in this specification, the “no load state” means an operation state in which the load 36 does not consume power.

  A flywheel 38, a cooling fan 40, and a start recoil starter 42 are attached to the other end of the crankshaft 32. A power coil (power generation coil) 44 is attached to the crankcase 30 inside the flywheel 38, and a magnet (permanent magnet) 46 is attached to the back of the flywheel 38. The power coil 44 and the magnet 46 constitute a multipolar generator and generate an output synchronized with the rotation of the crankshaft 32.

  A pulsar coil 48 is attached to the crankcase 30 outside the flywheel 38, and a magnet (permanent magnet) 50 is attached to the surface of the flywheel. The pulsar coil 48 generates an output indicating a crank angle corresponding to the ignition timing of the engine 10 every time the magnet 50 passes.

  A camshaft 52 is rotatably accommodated in the crankcase 30 in parallel with the axis of the crankshaft 32 and is connected to and driven by the crankshaft 32 via a gear mechanism 54. The cam shaft 52 includes an intake side cam 52a and an exhaust side cam 52b, and drives the intake valve 24 and the exhaust valve 26 via push rods and rocker arms 56 and 58 (not shown).

  A carburetor 60 is connected to the intake port 20. The carburetor 60 is integrally provided with an intake passage 62, a motor case 64, and a carburetor assembly 66. A throttle valve 68 and a choke valve 70 are disposed in the intake passage 62.

  The motor case 64 houses a throttle electric motor (actuator) 72 that drives the throttle valve 68 and a choke electric motor (actuator) 74 that drives the choke valve 70. The throttle electric motor 72 and the choke electric motor 74 are stepping motors.

  The carburetor assembly 66 is supplied with fuel from a fuel tank (not shown), injects an amount of fuel corresponding to the opening of the throttle valve 68 (and the choke valve 70), and mixes it with the intake air flowing through the intake passage 62. Is generated.

  The generated air-fuel mixture is sucked into the combustion chamber 18 through the intake port 20 and the intake valve 24, and is ignited through the ignition device and burned. Exhaust generated by the combustion is discharged to the outside of the engine 10 through an exhaust valve 26, an exhaust port 22, a silencer (not shown), and the like.

  A throttle opening sensor 76 is disposed in the vicinity of the throttle valve 68 and outputs a signal corresponding to the opening of the throttle valve 68 (hereinafter referred to as “throttle opening”), and a thermistor or the like is provided at an appropriate position of the cylinder block 12. A temperature sensor 78 consisting of is provided to produce an output indicative of the temperature of the engine 10.

  The outputs of the throttle opening sensor 76, the temperature sensor 78, the power coil 44, and the pulsar coil 48 are sent to an electronic control unit (hereinafter referred to as "ECU") 84. The ECU 84 includes a microcomputer including a CPU, a ROM, a RAM, an input / output circuit, and the like, and includes a warning lamp 84a.

  In the ECU 84, the output (AC power) of the power coil 44 is input to the bridge circuit, is full-wave rectified and converted into a DC power source, and is used as an operating power source for the ECU 84, the electric motor 72 for throttle, etc. Converted to a pulse signal. The output of the pulsar coil 48 is used as an ignition signal for the ignition device.

  In the ECU 84, the CPU detects the engine speed based on the converted pulse signal, and based on the detected engine speed, the output of the throttle opening sensor 76 and the temperature sensor 78, the throttle electric motor 72 and the choke electric motor 74. And controlling ignition through an ignition device.

  As described above, the engine 10 includes the electronic governor 90 that adjusts the engine speed through the actuator (throttle electric motor 72) that drives the throttle valve 68 disposed in the intake passage 62.

  Further, in the ECU 84, the CPU determines whether or not the load 36 such as the connected work machine is in a no-load state in which power is not consumed.

  FIG. 2 is a flowchart showing the operation, that is, the operation of the no-load detection apparatus and the no-load detection method according to the embodiment of the present invention. The illustrated program is executed by the ECU 84 every predetermined time, for example, every 10 msec.

  Explaining below, whether or not the engine speed detected in S10 is less than the speed obtained by adding a constant to the target speed and greater than the speed obtained by subtracting the constant from the target speed, In other words, it is determined whether or not the engine speed has converged to the target speed.

  The target rotational speed is an engine rotational speed determined according to the load 36 to be connected. The constant indicates a minute value of about 100 to 200 rpm, for example.

  Thus, in S10, whether or not the engine 10 is stably rotating in the normal rotation range determined according to the load 36, more specifically, the type of the load 36 to be connected (type of work implement). judge.

  When the result in S10 is negative, the subsequent processing is skipped. When the result is affirmative, the process proceeds to S12, and the threshold value is larger than a value (opening) obtained by adding a predetermined value to the detected throttle opening. Determine whether or not. The initial value of the threshold is set to an appropriate value. The predetermined value is, for example, a value of about 3 degrees at the throttle opening.

  When the result in S12 is affirmative, the program proceeds to S14, and the threshold value is changed (set) to a value obtained by adding the predetermined value to the detected throttle opening. When the result in S12 is negative, the process of S14 is skipped.

  Next, in S16, it is determined whether or not the detected throttle opening is less than the changed (set) threshold value. When the result in S16 is negative, the subsequent processing is skipped. When the result is affirmative, the process proceeds to S18 to increment the counter value C by one.

  Next, in S20, it is determined whether or not the counter value C exceeds a specified value n (for example, 300). That is, the value of the counter that counts the number C of times when the throttle opening detected in S18 becomes less than the threshold value is incremented by one.

  Next, in S20, it is determined whether or not the counted value (number of times) C exceeds a specified value n. Since the flowchart of FIG. 2 is executed at predetermined time intervals, the determination in S20 corresponds to determining whether a time corresponding to the specified value n, for example, 3 seconds has elapsed.

  When the result in S20 is negative, the subsequent processing is skipped. When the result is affirmative, the process proceeds to S22, and it is determined that the load 36 is in a no-load state that does not consume the power output from the engine 10. At the same time, the warning lamp 84a is turned on.

  FIG. 3 is a time chart for explaining the processing of FIG.

  The above description will be made with reference to the time chart of FIG. 3. In the determination of the no-load state according to this embodiment, for example, when it is between time t1 and t2, the determination in S12 is affirmed, and the process proceeds to S16 via S14. There it is affirmed. Also, from time t3 to t4, the determination in S12 is denied and the process proceeds to S16, where it is affirmed.

  That is, when the throttle opening is reduced as in those times, the determination in S16 is affirmed. However, it is not determined that there is no load by appropriately setting the specified value n.

  On the other hand, since the threshold value is decreased so as to be equal to the throttle opening + predetermined value at time t3 (it is time t3 for convenience of understanding, but is actually decreased at time t1), for example, the load decreases at time t5. Even so, as a result of the negative result in S16, the state in which such a small load is applied is not determined as a no-load state.

  Even when the determination at S16 is affirmed at time t6, the no-load state is determined accurately at time t7 when the time T (time corresponding to the specified value n) has elapsed. Can do.

  As described above, in this embodiment, the electronic governor 90 that adjusts the engine speed (engine speed) via the throttle electric motor (actuator) 72 that drives the throttle valve 68 disposed in the intake passage 62. And a throttle opening sensor (throttle opening detecting means) 76 for detecting the opening of the throttle valve 68 in an engine (general-purpose internal combustion engine) 10 connected to a load 36 and outputting power, and the engine rotation Power coil 44 for detecting the number (engine speed), ECU 84 (engine speed detecting means), and determining whether or not the detected engine speed has converged to a target speed determined in accordance with the load And target engine speed convergence determining means (ECU84, S10), and the detected engine speed converges to the target engine speed. A threshold value setting means (ECU84, S12, S14) for setting (changing) a threshold value to a value obtained by adding a predetermined value to the detected throttle valve opening, Counting means (ECU 84, S18) for counting the number C of times when the throttle valve opening is less than the threshold value, and when the counted number C exceeds a specified value n, the load does not consume power. No load state determination means (ECU 84, S20, S22) for determining that there is no load state, that is, find the throttle opening when rotating stably in the steady operation region, more than that Since a threshold value is set at a position above a predetermined value, and when the number of times C exceeds a specified value n when the detected value is less than the threshold value, it is determined that there is no load. The no-load condition can be appropriately set the threshold can be determined accurately.

In addition, when the number C of times when the detected opening of the throttle valve has become less than the threshold value exceeds a specified value n, it is determined that the no-load state is established, so that the predetermined value is appropriately set to be small. A state where a load is applied is not determined as a no-load state.
did.

  In the above description, constants and predetermined values are fixed values, but may be changed according to the load 36.

  In addition, when it is determined that there is no load, the warning lamp 84a is turned on to notify the user, but it may be notified via another display device or sound.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an overall no-load detection device for a general-purpose internal combustion engine according to an embodiment of the present invention. It is a flowchart which shows operation | movement of the apparatus shown in FIG. It is a time chart explaining the process of FIG.

Explanation of symbols

  10 engine (general-purpose internal combustion engine), 44 power coil (engine speed detection means), 60 carburetor, 68 throttle valve, 72 electric motor for throttle (actuator), 76 throttle opening sensor (throttle opening detection means), 84 ECU (Electronic control device. Engine speed detection means, no-load determination device), 90 electronic governor

Claims (2)

In a general-purpose internal combustion engine that includes an electronic governor that adjusts the engine speed via an actuator that drives a throttle valve disposed in an intake passage, and that outputs power by being connected to a load.
a. Throttle opening detecting means for detecting the opening of the throttle valve;
b. Engine speed detecting means for detecting the engine speed;
c. Target rotational speed convergence determination means for determining whether or not the detected engine rotational speed has converged to a target rotational speed determined according to the load;
d. Threshold setting means for setting a threshold to a value obtained by adding a predetermined value to the detected opening of the throttle valve when it is determined that the detected engine speed has converged to the target speed When,
e. Counting means for counting the number of times the detected throttle valve opening is less than the threshold;
f. When the counted number exceeds a specified value, a no-load state determination unit that determines that the load is in a no-load state that does not consume power,
A no-load detection device for a general-purpose internal combustion engine, comprising: In a general-purpose internal combustion engine that includes an electronic governor that adjusts the engine speed via an actuator that drives a throttle valve disposed in an intake passage, and that outputs power by being connected to a load.
a. It is determined whether or not the detected engine speed has converged to a target speed determined according to the load,
b. When it is determined that the detected engine speed has converged to the target speed, a threshold is set to a value obtained by adding a predetermined value to the detected throttle valve opening;
c. Count the number of times the detected throttle valve opening is less than the threshold,
d. When the counted number exceeds a specified value, it is determined that the load is in a no-load state that does not consume power.
A non-load detection method for a general-purpose internal combustion engine comprising steps.

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