JP2009216055A - Electronic governor device for general purpose engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve responsiveness of a throttle valve when a load is reduced by controlling throttle opening to take a balance with a target engine speed in a range of opening more than a predetermined opening, and thereafter, maintaining balance of opening of the throttle valve in a turning position by turning the throttle valve to the closing direction till the time just before getting instable turning condition, in regard to an electronic governor device for a general purpose engine. <P>SOLUTION: In this electronic governor device 2 for a general purpose engine, when a stable operation determining means 45 determines stable operation, in which engine speed takes a balance with a target speed, an operation range determining means 47 determines a case wherein opening of the throttle valve 9 in stable operation exceeds about 60% of full open of the throttle valve, this device controls the throttle valve 9 to turn to the closing direction per a certain opening, and controls throttle position to turn to the closing direction till the time just before a determination of instability is made, thereby improving the responsiveness of the throttle valve when the load is reduced. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electronic governor device for a general-purpose engine, and more particularly to an electronic governor device for a general-purpose engine that has a throttle valve that is driven to open and close by an actuator and controls the amount of air flowing to a carburetor by opening / closing control of the throttle valve.

For general-purpose engines, mechanical governors consisting of weights and springs have been the mainstream. However, in work machines that do not like rotational fluctuations such as generators, the electronic control that operates the throttle valve of the carburetor with an actuator such as a stepping motor. Some governors are employed.
In general-purpose engines, a structure in which an air-fuel mixture obtained by mixing air and gasoline fuel using a carburetor is ignited by a spark plug in a combustion chamber is employed.

  The relationship between the amount of air flowing through the carburetor with respect to the throttle opening, that is, the relationship between the engine output with respect to the throttle opening, generally decreases because the pressure difference between the upstream side and the downstream side of the throttle valve decreases as the throttle opening increases. As shown in FIG. 8, the smaller the throttle opening, the larger the change in the intake air amount relative to the change in the throttle opening, and the larger the throttle opening, the smaller the change in the intake air amount relative to the change in the throttle opening. It is known to be.

For this reason, Patent Document 1 (Japanese Patent Laid-Open No. 2003-314306) and Patent Document 2 (Japanese Patent Laid-Open No. 2003-2003) are proposed in order to improve the responsiveness of the rotational speed control over the entire range from a small opening to a large opening of the throttle valve. No. 314307) is known.
In this patent document 1, even when the throttle valve is located near the fully open position by interposing the first gear and the second gear, which are eccentric gears, between the output shaft of the actuator and the throttle valve, The response of the throttle valve to the movement is prevented from deteriorating.
Also in Patent Document 2, an output transmission mechanism including a link lever mechanism is interposed so that the response of the throttle valve to the movement of the actuator does not deteriorate even when the throttle valve is located near the fully open position. .

  On the other hand, general-purpose engines are often used at a constant rotational speed, and general-purpose engines for generators need to perform stable constant-rotation operation in order to generate power at a constant frequency. Therefore, stable operation with good responsiveness to load fluctuations (power generation load fluctuations) is desired.

JP 2003-314306 A JP 2003-314307 A

  The techniques described in Patent Document 1 and Patent Document 2 are designed so that the response of the throttle valve does not deteriorate with respect to the movement of the actuator over the entire range from the small opening to the large opening of the throttle valve. However, it is not sufficient for improving the response to load fluctuations.

As described above, in the output characteristics of the general-purpose engine, the smaller the throttle opening, the larger the change in the intake air amount with respect to the change in the throttle opening, and the larger the throttle opening, the more the change in the throttle opening. Therefore, the change in the intake air amount tends to be small.
Therefore, in order to prevent the rotation speed from dropping when the load increases, the throttle valve is fully opened and then moved to the closing side to be in equilibrium with the target rotational speed (see position P in FIG. 8). Thus, the throttle valve opening is controlled to be maintained.
However, when there is a load loss (decrease) from this equilibrium position P, the throttle valve is on the fully open side, so it is not suitable for rapid rotational speed reduction control and has a sufficient response to load loss. It cannot be obtained, and there is a risk that the rotational speed will rise rapidly and damage the driven device of the engine.

  Accordingly, the present invention has been made in view of such a background, and relates to an electronic governor device for a general-purpose engine, and when the load increases, the throttle valve is fully opened and then the throttle valve is turned to the closed side until the target rotational speed is reached. Then, after controlling to the target rotational speed and the equilibrium state, when the throttle opening is equal to or larger than a predetermined value, the throttle valve opening is rotated in the closing direction until the unstable rotation state is reached and the rotation position is reached. Thus, an object of the present invention is to improve the responsiveness of the throttle valve when the load is reduced by maintaining the equilibrium state.

  In order to solve the above-mentioned problems, the present invention provides an electronic governor device for a general-purpose engine in which a throttle valve of a carburetor provided in an intake passage is driven to open and close by an actuator. The operation region for determining whether the throttle opening is about 60% or more of the throttle fully opened when the stable operation determination unit determines that the stable operation is performed. When the determination means and the operation region determination means determine that the throttle opening is about 60% or more, the throttle valve is rotated in the closing direction at every fixed opening, and the stable operation determination means And stable throttle control means for controlling the rotation of the throttle position until immediately before being determined.

  According to this invention, the operation region determination means for determining whether or not the slot opening during the stable operation is in an opening region that is about 60% or more of the throttle fully open, in equilibrium with the target rotational speed, and the operation region determination When it is determined by the means that it is in an area of about 60% or more, the throttle valve is rotated in the closing direction at every predetermined opening, and the throttle position is immediately before it is determined to be unstable by the stable operation determining means. And a stable throttle control means for controlling the rotation of the throttle valve. Therefore, in the stable state in a large region where the throttle valve opening is about 60% or more, the throttle valve opening is adjusted until immediately before the unstable rotation state is reached. By rotating in the closing direction and maintaining the equilibrium state at the rotation position, the response of the throttle valve at the time of load reduction can be improved.

That is, since the equilibrium state with the target rotational speed is established as close as possible, even when there is a request for a load drop from the equilibrium state, for example, a reduction in the power generation load of the generator, the throttle against the load reduction. The movement of the valve can be followed quickly, and a responsive operation is possible.
As a result, it is possible to avoid the possibility that the engine speed is suddenly increased and the driven device of the engine is damaged when the load is reduced such as a load drop.

  Preferably, load increasing throttle control means is provided for controlling the throttle valve to a closed state by fully opening the throttle valve when the engine load is increased, and then rotating the throttle valve to the target rotational speed so as to be in equilibrium with the target rotational speed. After the control by the ascending throttle control means, the control by the stable throttle control means may be performed based on the determination results of the stable operation determination means and the operation region determination means.

According to such a configuration, when the engine load increases, the load increase throttle control means first opens the throttle valve fully in order to avoid a drop in the engine speed, and then rotates the throttle valve to the closed side until the target speed. Control is performed to bring the target rotational speed into equilibrium with the target rotational speed, and in this equilibrium state, control by the stable throttle control means is performed based on the determination results of the stable operation determination means and the operation region determination means.
Therefore, even when the throttle opening is in an equilibrium state on the fully open side by the throttle control, the throttle opening is moved in the closing direction while maintaining the equilibrium state. Responsiveness can be improved.

  Preferably, the throttle opening of the operating region determination means is about 50 ° or more with respect to 80 ° in the fully open state. Specifically, this means that the generator shown in FIG. According to the test results, when the fully open state is about 50 ° or more with respect to the throttle opening of 80 °, the power generation output changes little with respect to the throttle opening, so it is judged whether the stable operation state is in this region. By doing so, the throttle opening can be moved in the closing direction while maintaining an equilibrium state.

Preferably, the engine has a target rotational speed input unit for setting the target rotational speed, the engine is a generator engine, and the target rotational speed according to the power generation frequency is set by the target rotational speed input unit. .
According to such a configuration, the rotation speed according to the power generation frequency can be set by the target rotation speed setting means, and stable power can be output even if the power generation load varies.

  Further, preferably, the actuator is a stepping motor, and the throttle position control by the stable throttle control means may close the throttle opening for each step of the stepping motor, and the throttle valve opening for each step using the stepping motor. Since the control can be performed, the throttle opening degree can be reliably controlled.

  According to the present invention, an electronic governor device for a general-purpose engine, after the throttle valve is fully opened when the load is increased, and then the throttle valve is turned to the closed side until the target rotational speed is controlled to be in equilibrium with the target rotational speed. When the throttle opening is equal to or greater than a predetermined value, the throttle valve opening is rotated in the closing direction until the unstable rotation state is reached, so that the equilibrium state is maintained at the rotation position. It is possible to provide an electronic governor device that improves the response of the throttle valve when lowered.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, and are merely illustrative examples. Only.

  FIG. 1 is a side view of an external appearance of a main part of a general-purpose engine 1 according to the present invention from which a fuel tank, a fan cover, a starter, and an air cleaner are removed as viewed from the crankshaft direction. FIG. 3 is an overall configuration block diagram including the electronic governor device 2 according to the present invention.

  1 and 2, the general-purpose engine 1 is composed of a single-cylinder four-cycle engine. The engine body 3 is inclined and an intake passage 5 is connected to a side portion of the engine body 1. A carburetor 7 is attached upstream of the carburetor 7 and a throttle valve 9 (FIG. 3) is disposed inside the carburetor 7. A stepping motor (actuator) 11 for driving the throttle valve is disposed at the end of the carburetor 7. Opened and closed.

  A stepping motor 11 that opens and closes the throttle valve 9 is operated by a command from a motor driver unit 13 of the electronic governor device 2. A mixture of air and fuel adjusted by the throttle valve 9 is supplied to the engine combustion chamber and burned, and then discharged from the exhaust muffler 15 through the exhaust passage.

  In addition, as shown in FIG. 2, an example is shown in which a generator 19 is mounted on the output shaft 17 although various engine loads can be mounted. A flywheel 21 connected to a crankshaft is attached to the opposite side of the output shaft 17, and the generated alternating current is converted into direct current by a flywheel magnet 23 and a power generation coil 25 through a rectifier circuit (not shown) and then ignited. It is supplied to the spark plug 31 via the ignition coil 29 of the device 27. The ignition device 27 is started to operate when the main switch 33 (FIG. 3) is turned on.

  Further, a crank angle sensor (rotation angle sensor) 35 including a pickup (not shown) is provided in the vicinity of the flywheel 21, and a pulse is output at every predetermined crank angle and input to the rotation speed detection unit 37 of the electronic governor device 2. . The ignition signal from the ignition coil 29 is also input to the rotation speed detection unit 37 as an ignition pulse. A cooling fan 39 for cooling that is rotated by a crankshaft is mounted outside the flywheel 21.

  Next, the electronic governor device 2 in the general-purpose engine 1 configured as described above will be described. As shown in FIG. 3, the electronic governor device 2 includes a target rotation speed input unit 41, a rotation speed detection unit 37, a throttle opening calculation unit 43, and a motor driver unit 13.

In the target rotational speed input unit 41, a target engine rotational speed is set according to the application of the engine load attached to the output shaft 17. In the case of the generator 19, the target rotational speed is set to the rotational speed corresponding to the power generation frequency.
The rotation speed detector 37 detects the rotation pulse signal from the crank angle sensor (rotation angle sensor) 35 and the ignition pulse signal from the ignition coil 29 and outputs the engine rotation speed signal to the throttle opening calculation means 43. .
The motor driver unit 13 receives a throttle operation command signal from the throttle opening calculation means 43 and outputs an operation control signal to the stepping motor 11 of the throttle valve 9.

  The throttle opening calculation means 43 includes a stable operation determination means 45 for determining whether the engine is operating at a stable rotational speed with respect to the target rotational speed set by the target rotational speed input unit 41, and the stable operational determination. When the means 45 determines that the slot opening is about 60% or more of the throttle fully open, the operation area determination means 47 for determining whether or not the slot opening is about 60% or more. When the determination is made, the stable throttle control means for rotating the throttle valve 9 in the closing direction at every predetermined opening degree and controlling the rotation of the position of the throttle valve 9 until immediately before the stable operation determining means 45 determines that it is unstable. 49, and further, when the engine load is increased, the throttle valve is fully opened, and then the throttle valve is turned to the closed side until the target rotational speed to control the target rotational speed to be balanced. It is configured to include a load increase throttle control unit 51 for.

Next, the control of the throttle opening calculation means 43 will be described with reference to the flowchart shown in FIG.
First, when starting in step S1, the generated voltage from the generator coil 25 is confirmed in step S2, and it is confirmed whether the stepping motor 11 is in a drivable state. Thereafter, in step S3, the throttle position is initialized. Since the opening position of the throttle valve 9 is clearer than the fully closed state and is in the 80 ° rotation position, the number of operation steps of the stepping motor 11 at that position (for example, a stepping motor that moves 1 ° in one step) In this case, the position of the throttle valve 9 and the position of the stepping motor 11 are initialized on the basis of 80 steps fully opened).

  Next, in step S4, the target rotational speed is calculated based on the target rotational speed signal from the target rotational speed input unit 41. In step S5, the engine speed is calculated based on the engine speed signal from the speed detector 37.

  Next, in step S6, it is determined whether the rotational speed is stable. This determination is made when the deviation between the target engine speed in step S4 and the actual engine speed in step S5 converges within a certain value. If the deviation is within a certain value, it is determined that the rotational speed is stable, and the process proceeds to step S7, where it is determined by the operation region determination means 47 whether the opening of the throttle valve 9 exceeds 50 °. If so, the throttle valve 9 is driven in step S10 so that the throttle valve 9 is closed by one step in step S8.

That is, the motor driver unit 13 is commanded to the stepping motor 11 to operate in the closing direction by one step.
Thus, the opening degree control of the throttle valve 9 can be controlled for each step using the stepping motor 11, so that the throttle opening degree can be reliably controlled.

  If the throttle valve 9 is less than 50 ° in step S7, it is determined that the air amount is not in the throttle valve opening region where the air amount is stable with respect to the change in the throttle valve opening, and the process returns to step S4.

  If it is determined in step S6 that the rotational speed is not stable, the routine proceeds to step S9, where the throttle operation amount is calculated so as to be stable, and the throttle valve 9 is driven in step S10. That is, the throttle operation amount is calculated by the detailed routine of step S9 shown in FIG. 5, and the result is instructed to the motor driver unit 13.

  Next, proceeding to step S11, it is determined whether or not the main switch has been turned off. If it is turned off, stop processing is performed at step S12 and the process ends at step S13. If the main switch is not turned off, Returning from step S11 to S4 again, the procedure from step S4 is repeated.

The opening degree of the throttle valve 9 is set to 50 ° based on the result of an output test using an actual general-purpose engine and a generator as a load, as shown in FIG.
Since the throttle valve 9 is in a fully open state of 80 °, the power generation output changes little with respect to the throttle opening when the opening is about 50 ° (about 62%) or more with respect to the fully opened throttle opening.
FIG. 7 shows the relationship between throttle opening and output at a predetermined engine speed (for example, 1800 rpm, 2400 rpm, etc.) with the throttle opening on the horizontal axis and the generator output on the vertical axis. It is shown.

  By determining whether or not it is in the range of about 50 ° or more at any rotation speed, it is determined that the output is stable even if the throttle opening is changed and the output is stable. it can. As a result, when the throttle opening exceeds 50 °, there is no large fluctuation in the output even if the throttle opening is moved in the closing direction while maintaining the equilibrium state, and the throttle valve is maintained in the stable output state. The throttle valve can be moved to the closed side.

  That is, in the prior art, when the load is increased, the throttle valve is fully opened and then moved to the closing side to be in equilibrium with the target rotational speed, the throttle valve opening at the position P in FIG. However, in the present invention, the throttle valve can be moved to the Q position on the closing side while maintaining stable output from the P position in FIG.

  Next, a detailed routine of step S9 will be described with reference to FIG. First, when starting in step S21, a deviation between the target engine speed in step S4 and the actual engine speed in step S5 is calculated in step S22, and an operation amount θth of the throttle valve 9 corresponding to the deviation is calculated in step S23. To do. In step S24, a time Tth required to move the operation amount θth is calculated. The operation time Tth is calculated based on the motor rotation speed of the 1-2 phase control of the stepping motor 11.

  In step S25, the control cycle, that is, the control cycle calculated from the engine speed (cycle number) is compared with the operation time Tth calculated in step S24. If the operation time Tth is longer than the control cycle, Proceeding to step S26, the stepping motor 11 is operated by the two-phase control. When the operation time Tth is not longer than the control cycle, the process proceeds to step S27, and the stepping motor 11 is operated by 1-2 phase control. Then, the process ends in step S28 and returns to the main routine of FIG.

As a modified example of the flowchart shown in FIG. 4, before determining whether or not the rotational speed in step S4 is stable, it is determined whether or not there has been load increase control from the stable state as shown in FIG. May be added. Other steps are the same as those in FIG.
As shown in FIG. 6, it is determined in step S16 whether the load increase control from the stable state has been performed. This load increase control is performed by the load increase throttle control means 51, and when the engine speed is operating in a stable state with respect to the target speed, the engine load increases, for example, the power generation load of the generator 19 increases. As a result, the engine load has increased, and in order to avoid a drop in the engine speed, the throttle valve is fully opened, and then the throttle valve 19 is operated to the closed side until the target speed is reached. This is the control of the throttle valve.

If it is determined in step S16 that the load increase control has been performed, the process proceeds to step S6 to determine whether the rotational speed is stable. The subsequent steps are the same as those after step S6 described in FIG. If there is no load increase control in step S16, the process proceeds to step S9, the throttle operation amount is calculated, and the process proceeds to control for driving the throttle valve 9 in step S10.
Thus, by determining whether or not the load increase control has been performed in step S16, it is possible to determine whether the equilibrium state with the target rotational speed has occurred on the fully open side of the throttle opening, so that the throttle valve after step S7 is closed. The effect by the moving control can be obtained with certainty.

According to the electronic governor device 2 of the above embodiment, when the opening degree of the throttle valve 9 is in a large opening range exceeding 50 ° and is in a stable state, the throttle valve 9 is in a stable state until immediately before the unstable rotation state is reached. Since the opening degree is rotated in the closing direction and the equilibrium state is maintained at the rotation position, the responsiveness of the throttle valve 9 at the time of load reduction can be improved.
That is, an equilibrium state with the target rotational speed is established on the closed side as much as possible. Therefore, even when there is a request for a load drop from the equilibrium state, for example, a reduction in the power generation load of the generator 19, etc. As a result, the movement of the throttle valve 9 can be quickly followed, and an operation with good responsiveness is possible.

  According to the present invention, an electronic governor device for a general-purpose engine, after the throttle valve is fully opened when the load is increased, and then the throttle valve is turned to the closed side until the target rotational speed is controlled to be in equilibrium with the target rotational speed. When the throttle opening is equal to or greater than a predetermined value, the throttle valve opening is rotated in the closing direction until the unstable rotation state is reached, so that the equilibrium state is maintained at the rotation position. Since the responsiveness of the throttle valve at the time of lowering can be improved, it is useful when applied to an electronic governor device of a general-purpose engine.

1 is an external side view of a general-purpose engine according to the present invention. It is an external appearance top view of the general purpose engine concerning the present invention. 1 is an overall configuration block diagram including an electronic governor device according to the present invention. It is a flowchart which shows control of a throttle opening calculating means. FIG. 5 is a flowchart showing details of a throttle operation amount calculation unit in FIG. 4. The modification of the flowchart of FIG. 4 is shown. It is explanatory drawing which shows the test result of a throttle valve opening degree and an engine output. It is explanatory drawing which shows the relationship between a throttle-valve opening degree and air quantity (engine output).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 General purpose engine 2 Electronic governor device 3 Engine main body 7 Vaporizer 9 Throttle valve 11 Stepping motor (actuator)
Reference Signs List 13 motor driver section 27 ignition device 37 rotation speed detection section 41 target rotation speed input section 43 throttle opening calculation means
45 Stable operation determination means 47 Operation region determination means 49 Stable throttle control means 51 Load increase throttle control means

Claims (5)

In an electronic governor device of a general-purpose engine that opens and closes a throttle valve of a carburetor provided in an intake passage by an actuator,
A stable operation determining means for determining whether the engine speed is in a balanced state with respect to the target speed and a stable operation, and the throttle opening when the stable operation determining means determines that the engine is in a stable state is the throttle fully open. An operating region determining means for determining whether or not it is approximately 60% or more, and when the operating region determining means determines that the throttle opening is approximately 60% or more, the throttle valve is closed at every constant opening. A general-purpose engine electronic governor apparatus, comprising: a stable throttle control unit that rotates in a direction and controls the throttle position until it is determined to be unstable by the stable operation determination unit.   When the engine load increases, the throttle valve is fully opened, and then the throttle valve is closed to the target rotational speed, and is controlled to be in equilibrium with the target rotational speed. 2. The electronic governor device for a general-purpose engine according to claim 1, wherein after the control is performed, control by the stable throttle control unit is performed based on determination results of the stable operation determination unit and the operation region determination unit.   2. The electronic governor device for a general-purpose engine according to claim 1, wherein the throttle opening degree of the operation region determination means is about 50 degrees or more with respect to 80 degrees in a fully opened state.   A target rotational speed input unit for setting the target rotational speed is provided, the engine is a generator engine, and a target rotational speed corresponding to a power generation frequency is set by the target rotational speed input unit. Item 10. An electronic governor device for a general-purpose engine according to Item 1.   2. The electronic governor device for a general-purpose engine according to claim 1, wherein the actuator comprises a stepping motor, and the throttle position is controlled at each step of the stepping motor by the throttle position control by the stable throttle control means.

Images