JP2005120917A - Engine-driven type compressor whose discharge pressure is variable and discharge pressure changing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an engine stall caused by deficiency in an engine output power needed for a compressor body even if a set value of discharge pressure of the compressor body is changed into a high value in an engine-driven type compressor driven by one engine. <P>SOLUTION: The discharge pressure of the compressor body 60 is beforehand set as a preset discharge pressure value within the predetermined compass. Then, when a compressed fluid discharged from the compressor body 60 is lower than the preset discharge pressure value, within the compass of an output power curve of an engine 80a a revolution speed of the engine 80 is made low with increasing compressed fluid pressure discharged from the compressor body 60, while the revolution speed of the engine 80 is made high with decreasing compressed fluid pressure discharged from the compressor body 60. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an engine-driven compressor discharge pressure changing method and an engine-driven compressor capable of changing the discharge pressure, and more particularly, in a single engine-driven compressor, the discharge pressure of the compressor body. The present invention relates to a method for changing the pressure of the compressed fluid supplied to the consuming side by changing the setting of the above, and an engine-driven compressor in which the discharge pressure can be changed in this way.

  As an example of an engine-driven compressor, an oil-cooled engine-driven compressor will be described as an example. This oil-cooled engine-driven compressor was obtained by compressing air and other fluids to be compressed. A compressor body that discharges the compressed fluid as a gas-liquid mixed fluid together with cooling oil for sealing and cooling the working space of the compressor body; and an engine that drives the compressor body. It has a receiver tank that stores the compressed fluid discharged as the liquid mixture fluid and separates the cooling oil, and takes out the compressed fluid that is stored in this receiver tank and separated from the cooling oil by piping, It is comprised so that it can supply.

  In such an engine-driven compressor, the pressure in the receiver tank is preset by the consumption of the compressed fluid or the like so that the compressed fluid can be constantly supplied to the consumption side. When the pressure is lower than the discharge pressure, the compressor inlet is opened, the compressed fluid is sucked into the compressor body and compressed, and the compressed fluid discharged from the compressor body is introduced into the receiver tank for consumption. When the pressure in the receiver tank exceeds the preset discharge pressure, the suction control is performed to close the suction port of the compressor body and stop introducing the fluid to be compressed into the receiver tank. Or when the pressure in the receiver tank is lower than the preset discharge pressure, the engine speed that drives the compressor body is increased and discharged from the compressor body. While increasing the discharge amount of the compressed fluid, when the pressure in the receiver tank becomes equal to or higher than a preset discharge pressure, the compressed fluid discharged from the compressor body is reduced by reducing the rotational speed of the engine that drives the compressor body. Speed control is performed to reduce the discharge amount.

  As an example of an engine-driven compressor provided with a control device that performs such suction control and speed control, as shown in FIG. 8, a butterfly valve that opens and closes the suction port 61 in the suction port 61 of the compressor body 60, and the like On / off valve 31 and an unloader regulator 32 for operating the on / off valve 31, and a suction control means 30 having a pressure regulator 40 ′ in a control line 90 communicating between the receiver tank 50 and the unloader regulator 32. There is an engine-driven compressor having speed control means including a speed regulator 70 for operating a governor lever 85 of the engine 80 by introducing a compressed fluid downstream of the receiver tank 50 through the regulator 40 '. 50 downstream pressures were preset by the pressure regulator 40 ' When the pressure falls below the output pressure, the compressed fluid downstream of the receiver tank 50 does not pass through the pressure regulator 40 ', the unloader regulator 32 operates the on-off valve 31 to open the inlet 61 of the compressor body 60, and the speed regulator 70 moves the governor lever 85 of the engine 80 to the high speed side, while when the pressure downstream of the receiver tank 50 rises above the discharge pressure preset by the pressure regulator 40 ′, compressed fluid is introduced into the unloader regulator 32. Then, there is a valve in which the on-off valve 31 closes the suction port 61 of the compressor body 60 and the speed regulator 70 performs an operation of moving the governor lever 85 of the engine 80 to the low speed side (see Patent Document 1).

  The engine speed control by the speed control means includes the engine no-load rotational speed (low speed) when the compressor body is in no-load operation, and the engine full-load speed (high speed) when the compressor body is in full-load operation. In this range, the rotational speed of the engine is changed between the high speed and the low speed in accordance with the change of the pressure of the compressed fluid discharged from the compressor body, that is, the pressure downstream of the receiver tank.

  The engine used as the drive source of the compressor body is stabilized in rotational speed by a governor (governor). Of the output curves of the engine in which the governor lever 85 is moved to the high speed side in FIG. Considering the state in which the control region by the governor and the power performance of the compressor body having the first pressure constant intersect (balance point), the state of the compressed fluid discharged from the compressor body 60 from this state is considered. When the pressure rises, the power of the compressor body increases, and until the engine output balances with the power of the compressor body, the amount of fuel supplied to the engine increases to increase the engine output and conversely compress When the pressure of the compressed fluid discharged from the machine main body 60 decreases, the power of the compressor main body decreases, and until the engine output balances with the power of the compressor main body, By reducing the amount of fuel supplied per unit time to reduce the output of the engine.

  In addition to the above-described configuration, the speed control means and the governor are replaced with the pressure regulator 40 'and the speed regulator 70 described above, and the pressure of the compressed fluid discharged from the compressor body 60 is detected by a sensor or the like. The detection signal is input to the controller, and when the pressure reaches a preset value based on the detection signal, the actuator is controlled to reduce the engine speed, and the engine speed is measured by a sensor or the like. There is one that detects and inputs this detection signal to a controller, and controls the actuator so that the engine speed is maintained at a speed preset by the controller (see Patent Document 2).

Prior art document information of the present invention includes the following.
Japanese Utility Model Publication No. 6-23755 (page 1-3, FIG. 1) JP 61-258939 A (page 1-2, FIG. 1)

  An engine-driven compressor takes into account variations in engine output and compressor body power that are permitted in manufacturing, and fluctuations in engine output and compressor body power due to differences in operating environments. An engine having an output curve that is higher than the power performance by a predetermined margin (appropriate margin) is selected. For example, an engine having a rated output that is 5% higher than the rated power of the compressor body is combined.

  For example, when the margin is too small, the engine whose output is lower than the allowable range is combined with the compressor main body whose power is the upper limit of allowable power, or the engine is operated at high altitude where the output of the engine decreases due to thin air. Sometimes, the power of the compressor body exceeds the output of the engine, and the engine cannot drive the compressor body. If the margin is excessive, the engine becomes large and expensive and manufactured. Engine-driven compressors themselves are expensive and large, and are not economical in terms of increased fuel consumption.

  By the way, when an air compressor used at a construction site or the like is taken as an example, the pressure of the compressed air supplied by the air compressor varies depending on the application.

  For example, compared to compressed air used in air blow work, painting work, concrete spraying work, etc., compressed air used in down-the-hole construction methods, large bore boring work, etc. is required to have a higher pressure. In an engine-driven compressor that supplies compressed air to be used, it is necessary to supply higher-pressure compressed air to the consumption side as compared with a general engine-driven compressor.

  However, as described above, in the combination of the compressor main body and the engine having an output curve with an appropriate margin for the power performance of the compressor main body, only the discharge pressure setting of the compressor main body is set according to the intended use. If the engine power is changed, and the discharge pressure setting is increased, the engine output curve margin becomes too small for the power performance of the compressor body. When used at high altitudes where the output decreases, the engine output becomes insufficient and stalls, or the power required to drive the compressor body exceeds the engine output curve and the engine drives the compressor body Problems such as being unable to do so occur. Conversely, when the discharge pressure setting is decreased, for example, as shown in FIG. 9, when the setting of the pressure of the compressed air discharged from the compressor main body is changed from the first pressure to the second pressure, the engine drives the compressor main body. Although it will not be impossible, it is used in the state where the margin of the output curve of the engine is excessive with respect to the power performance of the compressor main body, and originally has an appropriate margin for the power performance of the compressor main body. Compared to an engine-driven compressor combined with an engine having a given output curve, the engine is large and expensive, and the manufactured engine-driven compressor itself is also expensive and large, and the fuel consumption increases. Not economical in terms.

  Therefore, in the case where the pressure of the compressed air required according to the application or the like is different as described above, an engine driven compressor is prepared separately according to the required pressure of the compressed air, or as described above. However, it is necessary to use the engine-driven compressor in a state that is not economical, and the economic burden is large.

  In the case of an engine-driven compressor that has a built-in speed increasing device in the compressor body and increases the rotational speed output from the engine by the speed increasing device to drive the compressor body, the speed increasing ratio By providing different speed increasing devices, the rotational speed of the compressor main body can be made different even in the same output state by the same engine, so that the setting of the discharge pressure of the compressor main body can be changed. However, in this case, when the discharge pressure setting is lowered, the speed increasing ratio of the speed increasing device is increased to increase the discharge amount of compressed air, and when the discharge pressure setting is increased, the speed increasing device It is necessary to change the speed increasing ratio of the speed increasing device, such as reducing the speed increasing ratio to reduce the discharge amount of compressed air.

  Therefore, even in such an engine-driven compressor, in one engine-driven compressor, it is not a structure that can change the discharge pressure setting of the compressed fluid supplied to the consumption side to be high. .

  Accordingly, an object of the present invention is to solve the above-mentioned drawbacks in the prior art, and is combined with an engine having an output curve with an appropriate margin for the power performance of the compressor body. Engine-driven compression that can prevent engine stall due to insufficient engine output relative to the power of the compressor body, even if the discharge pressure setting of the compressor body is changed to a high level in an engine-driven compressor The purpose is to provide a machine.

In order to achieve the above object, a discharge pressure changing method for an engine-driven compressor according to the present invention is an engine-driven compressor in which a compressor body 60 that introduces and compresses a fluid to be compressed is driven by an engine 80.
When the discharge pressure of the compressor body 60 is set as a preset discharge pressure value in a predetermined range in advance, and the pressure of the compressed fluid discharged from the compressor body 60 is lower than the set discharge pressure value,
Within the range of the output curve of the engine 80, as the pressure of the compressed fluid discharged from the compressor body 60 increases, the rotational speed of the engine 80 is decreased and the pressure of the compressed fluid discharged from the compressor body 60 decreases. Accordingly, the rotational speed of the engine 80 is increased (claim 1).

The range of the set discharge pressure value is within the range of the set maximum pressure and the set minimum pressure, and the engine speed except for the range of the full load speed r ₅ and the no-load maximum speed r ₄ of the engine 80. The number of rotations can be controlled within a range (claim 2).

In the above, the set maximum pressure and the set minimum pressure are the maximum and minimum pressures that can be set as the discharge pressure of the compressor body, and the full load rotation speed r ₅ is the compressor corresponding to the set discharge pressure value. refers to the rotational speed of the engine 80 at the rated power (full load) upon the occurrence of the main body 60, the no-load maximum speed r _5, in a state in which the engine is driven at the rated power corresponding to the set discharge pressure value, This refers to the engine speed that is reached when the compressor body shifts to no-load operation (see FIG. 6).

  In the above-described discharge pressure changing method, a correspondence relationship between the pressure of the compressed fluid discharged from the compressor main body 60 having a power lower than the output curve of the engine 80 by a predetermined margin and the rotational speed of the engine 80 is obtained in advance. The rotational speed of the engine 80 is calculated from the pressure of the compressed fluid discharged from the compressor body 60 based on this correspondence.

  Further, when the pressure of the compressed fluid discharged from the compressor main body 60 is equal to or higher than the preset discharge pressure value, the amount of fuel supplied to the engine 80 per unit time is reduced to reduce the rotational speed of the engine 80. Is preferably reduced (claim 4).

  Furthermore, it is preferable that the suction port of the compressor main body 60 is throttled or closed when the pressure of the compressed fluid discharged from the compressor main body 60 is equal to or higher than the preset discharge pressure value (Claim 5). .

The engine-driven compressor of the present invention configured to be able to change the discharge pressure is an engine-driven compressor in which a compressor main body 60 that introduces and compresses a fluid to be compressed is driven by an engine 80.
When the discharge pressure of the compressor body 60 is set as a preset discharge pressure value in a predetermined range in advance, and the pressure of the compressed fluid discharged from the compressor body 60 is lower than the set discharge pressure value,
Within the range of the output curve of the engine 80, as the pressure of the compressed fluid discharged from the compressor body 60 increases, the rotational speed of the engine 80 is decreased and the pressure of the compressed fluid discharged from the compressor body 60 decreases. Accordingly, the drive control device 1 for increasing the rotational speed of the engine 80 is provided (claim 6).

  In the engine-driven compressor having the above-described configuration, the drive control device 1 determines the pressure of the compressed fluid discharged from the compressor main body 60 having a power lower than the output curve of the engine 80 by a predetermined margin and the engine 80. The number of rotations of the engine 80 is calculated from the pressure of the compressed fluid discharged from the compressor main body 60 based on this storage.

In the engine-driven compressor configured as described above, the drive control device 1 sets the discharge pressure of the compressor body as a set discharge pressure value within a predetermined range, for example, a pressure setting volume 11b such as a changeover switch 11a or a variable resistor. , Pressure setting means 11 (pressure sensor 52) for detecting the pressure of the compressed fluid discharged from the compressor body 60, and rotation speed detection means (rotation speed sensor) for detecting the rotation speed of the engine 80. 53), a fuel supply device 81 that controls the amount of fuel supplied to the engine 80 in response to the received control signal, and an electronic control device 20 that transmits a control signal to the fuel supply device 81,
The electronic control unit 20 includes a storage unit 25 that stores a correspondence relationship between the pressure of the compressed fluid discharged from the compressor main body 60 and the rotational speed of the engine 80, and the detection of the pressure detection unit (pressure sensor 52). When the pressure to be performed is lower than the set discharge pressure value set by the pressure setting means 11 (11a, 11b), the pressure detection means (pressure sensor 52) is based on the correspondence stored in the storage means 25. The rotational speed of the engine 80 for operating the compressor main body 60 with the rated power is calculated from the pressure detected by the engine so that the rotational speed detected by the rotational speed detection means (the rotational speed sensor 53) becomes the calculated rotational speed. It is preferable to further comprise a rotation speed control means 21 for transmitting a control signal to the fuel supply device 81 (Claim 8).

  Further, the rotational speed control means 21 increases the amount of fuel supplied to the engine 80 per unit time when the rotational speed detected by the rotational speed detection means (the rotational speed sensor 53) is lower than the calculated rotational speed. A control signal is transmitted to the fuel supply device 81, and when the rotational speed detected by the rotational speed detection means (the rotational speed sensor 53) is higher than the calculated rotational speed, the amount of fuel supplied to the engine 80 per unit time is set. A decreasing control signal can be transmitted to the fuel supply device 81 (claim 9).

  Furthermore, the electronic control unit 20 further has a pressure detected by the pressure detection means (pressure sensor 52) that is equal to or higher than the set discharge pressure value set by the pressure setting means 11 (11a, 11b). Speed control means 22 may be provided for transmitting a control signal for reducing the amount of fuel supplied to the engine 80 per unit time to the fuel supply device 81 to reduce the engine speed (Claim 10).

Furthermore, a suction control means 30 for restricting or closing the suction port 61 of the compressor body 60 in response to the received control signal is provided,
The electronic control unit 20 further includes the compressor when the pressure detected by the pressure detection means (pressure sensor 52) is equal to or higher than the set discharge pressure value set by the pressure setting means 11 (11a, 11b). There may be provided an operation signal generating means 24 for reducing or stopping the introduction of the fluid to be compressed to the compressor main body 60 by transmitting an operation signal for restricting or closing the suction port 61 of the main body 60 to the suction control means 30 ( Claim 11).

  With the configuration of the present invention described above, the set discharge pressure value of the compressor body can be set with a single engine-driven compressor combined with an engine having an output curve with an appropriate margin for the power performance of the compressor body. To provide a discharge pressure method for an engine-driven compressor and an engine-driven compressor that can prevent engine stall due to insufficient engine output relative to the power of the compressor body even if it is highly changed. I was able to.

  Next, embodiments of the present invention will be described below with reference to the accompanying drawings.

  As shown in FIG. 1, an engine-driven compressor according to the present invention compresses sucked air (compressed fluid) and discharges compressed air (compressed fluid), and the compressor main body 60. An engine 80 for driving and a receiver tank 50 for storing compressed air discharged from the compressor main body 60 are provided, and the pressure of the compressed air discharged from the compressor main body is set discharge set in advance. FIG. 8 shows that a suction control means 30 is provided for reducing or stopping the introduction of compressed air to the compressor body by restricting or closing the suction port 61 of the compressor body when the pressure rises above the pressure value. The engine drive compressor in the prior art described with reference to FIG. 8 is the same as the engine drive compressor in the prior art described above with reference to FIG. In contrast, the vehicle is provided with a speed control means such as a governor for controlling the amount of fuel supplied to the engine 80, a speed regulator 70 for operating the governor lever 85 of this governor, and a pressure regulator 40 '. The compressor includes a rotational speed detection means (rotational speed sensor 53) for detecting the rotational speed of the engine 80 or the compressor main body 60, the pressure of the compressed air discharged from the compressor main body 60 (in the example of FIG. An electronic control unit 20 for providing a pressure detection means (pressure sensor 52) for detecting a downstream pressure) and transmitting a control signal for controlling the fuel supply amount in accordance with detection signals from the detection means, and the electronic A fuel supply device 81 that receives a control signal from the control device 20 and controls the amount of fuel supplied to the engine is provided. Drive control apparatus 1 is configured to perform drive control of the gin-driven compressor.

  Further, in the conventional engine-driven compressor shown in FIG. 8, the compressor body 60 and the engine 80 having an output curve with an appropriate margin for the power performance of the compressor body 60 are combined. When the set discharge pressure value of the compressor main body 60 is increased according to the usage, the output curve of the engine 80 is too small for the power performance of the compressor main body. Although the set discharge pressure value of the main body 60 cannot be changed to a high value, in the embodiment shown in FIG. 1, the electronic control unit 20 previously compresses within the range of the output curve of the engine. Based on the correspondence between the pressure of the compressed fluid discharged from the compressor main body 60 and the rotational speed of the engine 80, the power of the machine main body becomes lower than the engine output curve by a predetermined margin. Pressure When the pressure detected by the sensor 52) is lower than the set discharge pressure value set by the pressure setting means 11 including the changeover switch 11a and the like, the pressure of the engine 80 is detected from the pressure detected by the pressure detection means (pressure sensor 52). A rotational speed is calculated, and a control signal is transmitted to the fuel supply device 81 so that the rotational speed detected by the rotational speed detection means (the rotational speed sensor 53) becomes the calculated rotational speed.

  Further, in the prior art shown in FIG. 8, when the pressure downstream of the receiver tank 50 becomes equal to or higher than the discharge pressure determined by the operating pressure of the pressure regulator 40 ′, the suction control means 30 causes the suction port 61 of the compressor main body 60 to move. In the embodiment shown in FIG. 1, in place of the pressure regulator 40 ′, an electromagnetic valve that opens and closes in response to a received signal is configured. 37, and when the pressure of the compressed air discharged from the compressor body detected by the pressure detection means (pressure sensor 52) is equal to or higher than the set discharge pressure value set by the constant pressure setting means 11, When the operation signal for opening the electromagnetic valve 37 is generated and the pressure of the compressed air discharged from the compressor body is less than the set discharge pressure value, the electromagnetic valve 37 is turned on. Actuation signal generating means for generating a Jill actuation signal comprises the aforementioned electronic control unit 20.

[Drive control device]
In the engine-driven compressor shown in FIG. 1, a drive control device 1 that performs engine drive control includes an electronic control device 20, a changeover switch 11 a that is a pressure setting means 11 connected to the electronic control device 20, and a rotational speed. The sensor 53, the pressure sensor 52, and the fuel supply device 81 are included.

[Electronic control device]
The aforementioned electronic control device 20 receives the setting signal received from the aforementioned changeover switch 11a and / or the detection signal from each detection means, and receives the received setting signal and / or the control signal corresponding to the detection signal to each part. As shown in the functional block diagram of FIG. 2, the electronic control unit 20 stores a correspondence between input signals and output signals, for example, a storage means such as a ROM. 25 and an arithmetic processing unit composed of a central processing unit (CPU) or the like for performing arithmetic processing on a signal to be output based on the input signal in accordance with the correspondence stored in the storage means, and according to the input signal The calculation processing unit transmits a control signal based on the correspondence relationship stored in advance in the storage unit 25, whereby each unit is controlled.

  In the present embodiment, the electronic control unit 20 includes at least “revolution speed control means”, “speed control means”, and “storage means”, which will be described later, which constitute a drive control apparatus for an engine-driven compressor. The above-mentioned “operation signal generating means” for transmitting an operation signal to the electromagnetic valve 37 is provided.

  The electronic control device 20 is provided with an input terminal to which various sensors and switches are connected, and an output terminal to which various devices controlled by control signals transmitted from the electronic control device 20 are connected. Of these, pressure detection means (pressure sensor 52) for detecting the pressure of the compressed air discharged from the compressor main body 60 to the input terminal, the pressure on the downstream side of the receiver tank 50 in the illustrated embodiment, the engine 80 or the compression Rotation speed detection means (rotation speed sensor 53) for detecting the rotation speed of the machine main body 60 and preset discharge pressure value of the compressor main body 60 within a predetermined range, for example, a changeover switch 11a, a variable resistor, or the like A pressure setting means 11 comprising a volume 11b is connected, and an engine 8 is connected to an output terminal of the electronic control unit 20 in accordance with a control signal transmitted by the electronic control unit 20. A fuel supply device 81 for controlling the amount of fuel supplied to the valve, a solenoid valve 37 (FIG. 1), a solenoid, a motor, and other actuators (FIG. 5) operated by an operation signal output from the electronic control device 20 are connected. Has been.

(1) Rotational speed control means The rotational speed control means 21 provided in the electronic control unit 20 described above is within a range of the engine output curve stored in the storage means 25 and has a predetermined margin with respect to the engine output curve. 1 is provided downstream of the receiver tank 50 in the embodiment shown in FIG. 1 based on the correspondence relationship between the pressure of the compressed fluid discharged from the compressor main body 60 with lower power and the rotational speed of the engine 80. The pressure detected by the pressure sensor 52 is compared with the set discharge pressure value set by the pressure setting means 11 including the changeover switch 11a, and the pressure downstream of the receiver tank 50 is lower than the set discharge pressure value. Sometimes, the rotational speed of the engine 80 is calculated from the pressure detected by the pressure sensor 52, and the fuel supply device is set so that the rotational speed of the engine 80 becomes the calculated rotational speed. The storage means 25 transmits the control signal to the device 81, and the storage means 25 has a compressor body in which the power of the compressor body is lowered by a predetermined margin with respect to the engine output curve in advance within the range of the engine output curve. 60, the correspondence relationship between the pressure of the compressed fluid discharged from the compressor 60 and the rotational speed of the engine 80 is stored. This correspondence relationship indicates that the rotational speed of the engine 80 is high when the pressure of the compressed fluid discharged from the compressor body 60 is high. When the pressure of the compressed fluid discharged from the compressor main body 60 is low, the rotational speed of the engine 80 is high.

  Further, as shown in FIG. 3, the storage means 25 has a small inclination with respect to the inclination of the power performance of the compressor main body 60 as shown in FIG. If the output is constant, the correspondence relationship between the pressure of the compressed fluid discharged from the compressor main body 60 where the rated power of the compressor main body 60 is substantially the same and the rotational speed of the engine 80 is stored. Good.

  Further, as shown by a chain line in FIG. 7, an engine output margin line lower by a predetermined margin (for example, 5%) than the engine output line is assumed, and the engine output margin line and the power of the compressor main body are assumed. You may memorize | store the rotation speed of the said engine in the point which cross | intersects a line as a corresponding relationship with the pressure of a compressor main body.

  Further, the rotational speed control means 21 compares the rotational speed of the engine 80 detected by the rotational speed sensor 53 with the calculated rotational speed, and the rotational speed detected by the rotational speed sensor 53 is determined as described above. When the rotational speed is lower than the calculated rotational speed, a control signal for increasing the amount of fuel supplied per unit time to the engine 80 is transmitted to the fuel supply device 81, and the rotational speed of the engine 80 detected by the rotational speed sensor 53 When the rotational speed detected by the rotational speed sensor 53 is higher than the calculated rotational speed, the amount of fuel supplied to the engine 80 per unit time is reduced. A control signal is transmitted to the fuel supply device 81.

  Alternatively, the maximum rotational speed of the engine 80 is stored in the storage means 25, and the rotational speed control means 21 stores the engine 80 in which the rotational speed detected by the rotational speed sensor 53 is stored as the calculated rotational speed. When the engine speed is lower than any of the lower engine speeds, a control signal for increasing the amount of fuel supplied per unit time to the engine 80 is transmitted to the fuel supply device 81, and the engine speed is increased. When the rotational speed detected by the sensor is higher than any of the low rotational speeds by comparing the calculated rotational speed with the stored maximum rotational speed of the engine 80, the fuel per unit time for the engine 80 A control signal for reducing the supply amount of the engine 80 is transmitted to the fuel supply device 81, and the engine speed is stored as the above-mentioned calculated engine speed and the maximum engine speed. DOO can be so controlled to be low rotational speed either by comparing the.

(2) Speed Control Unit The electronic control unit 20 described above further includes a speed control unit 22 that performs the above-described speed control. The speed control unit 22 corresponds to the pressure of the compressed air discharged from the compressor body 60. The speed of the engine 80 is controlled between a high speed and a low speed, and the control corresponding to the control performed by the pressure regulator 40 ′ and the speed regulator 70 in the prior art described with reference to FIG. 8 is performed. The speed control by the speed control means 22 is different from the control by the rotation speed control means 21 described above, when the pressure detected by the pressure sensor 52 is equal to or higher than the set discharge pressure value set by the pressure setting means 11. The control is performed.

  The speed control means 22 includes the pressure of the compressed air discharged from the compressor main body 60, the pressure of the compressed air detected by the pressure sensor 52 provided downstream of the receiver tank 50 in the embodiment shown in FIG. When the pressure downstream of the receiver tank 50 is equal to or higher than the set discharge pressure value, the set discharge pressure value set based on the operation of the changeover switch 11a as the pressure setting means 11 is compared. A control signal for reducing or minimizing the amount of fuel supplied per unit time to the engine 80 is transmitted to the fuel supply device 81 so that the rotational speed of the engine 80 is reduced or unloaded, and from the compressor main body. The discharge amount of the compressed air to be discharged is controlled to maintain the pressure downstream of the receiver tank 50 at the set discharge pressure value. When the pressure downstream of the receiver tank 50 is less than the set discharge pressure value, control by the rotation speed control means 21 is performed.

(3) Actuation signal generating means The electronic control unit 20 described above further includes an actuation signal generating means 24 for transmitting a control signal for opening and closing the solenoid valve 37 in FIG. The operation signal generating means 24 provided in the electronic control device 20 does not constitute the drive control device 1 that controls the drive of the engine of the engine-driven compressor described above. However, in the present embodiment, this is provided in the electronic control device 20 constituting the drive control device 1 described above. For convenience of explanation, the drive control device described above is provided. 1 and will be described here.

  The operation signal generating means 24 is set by the changeover switch 11a which is the pressure setting means 11 so that the pressure of the compressed air discharged from the compressor body 60 is set by the detection signal received by the pressure sensor 52. When it is recognized that the discharge pressure value is exceeded, a drive signal for opening the solenoid valve 37 is transmitted.

  The device composed of the combination of the pressure sensor 52, the operation signal generating means 24 and the electromagnetic valve 37 compresses the suction control means 30 when the pressure downstream of the receiver tank 50 exceeds a set discharge pressure value. Although it operates in the same manner as the pressure regulator 40 ′ in the conventional engine-driven compressor described with reference to FIG. 8 in that the introduction of the fluid is started, Based on the set discharge pressure value set by switching the changeover switch 11a, the pressure regulator 40 ′ described above is variable in that the pressure downstream of the receiver tank 50 that starts the introduction of compressed air to the suction control means 30 is variable. Is different.

[Inhalation control means]
In the embodiment shown in FIG. 1, the aforementioned compressor body 60 has an intake control means 30 comprising an on-off valve 31 such as a butterfly valve that opens and closes an intake port 61 and an unloader regulator 32 that operates the on-off valve 31. The above-described electromagnetic valve 37 is provided in a control line 90 that is provided and communicates between the downstream of the receiver tank 50 and the unloader regulator 32, and is a receiver tank that is the pressure of compressed air discharged from the compressor body 60. When the pressure sensor 52 detects that the pressure downstream of the pressure 50 becomes equal to or higher than the set discharge pressure value set by the changeover switch 11a which is the pressure setting means 11, the operation signal output means 24 sends a control signal. The electromagnetic valve 37 is opened, and the unloader regulator 32 of the suction control means 30 is supplied with compressed air downstream of the receiver tank. Is input, throttle the intake port 61 of the compressor body 60 or closed is configured to start operating.

[Operation]
In the engine-driven compressor configured as described above, when the set discharge pressure value of the compressor main body 60 is changed to a high pressure, the above-described changeover switch 11a is operated and this switch is set to the “high pressure” position. Switch to.

  By operating the changeover switch 11a, a setting signal indicating that the changeover switch 11a has changed to “high voltage” is output to the electronic control unit 20.

  If the compressed air is compressed by driving the compressor main body 60 by the engine 80 after the changeover switch 11a is switched to “high pressure” in this way, the downstream of the receiver tank 50 is shortly after the compressor main body is started. Is less than the high set discharge pressure value set by the changeover switch 11a, the rotational speed control means 21 provided in the electronic control device 20 is based on the correspondence stored in the storage means 25. From the pressure detected by the pressure sensor 52, the rotational speed of the engine 80 for operating the compressor main body 60 with the rated power is calculated. A control signal for increasing the amount of fuel supplied per unit time to the engine 80 is transmitted to the fuel supply device 81 until the rotational speed detected by the rotational speed sensor 53 increases to the calculated rotational speed. When the rotational speed detected by the rotational speed sensor 53 is higher than the calculated rotational speed, a control signal for decreasing the amount of fuel supplied per unit time to the engine 80 is sent to the fuel supply device 81. To call. The pressure downstream of the receiver tank 50 always fluctuates depending on the balance between the supply amount of compressed air discharged from the compressor body and the consumption amount of compressed air consumed on the consumption side. The rotational speed of the engine 80 for operating the compressor main body 60 with the rated power is repeatedly calculated, and the rotational speed of the engine 80 is controlled to be the above-described calculated rotational speed.

  As shown in FIG. 3, the output curve of the engine 80 has a small slope with respect to the slope of the power performance of the compressor body 60, and the output remains substantially the same within the rated output constant range even if the rotational speed changes. The power of the compressor main body 60 is discharged from the compressor main body 60 where the power of the compressor main body 60 is lower by a predetermined margin than the engine output curve and the rated power of the compressor main body 60 is substantially the same. When the correspondence relationship between the pressure of the compressed fluid and the rotational speed of the engine 80 is stored, the relationship between the pressure detected by the pressure sensor 52 and the rotational speed calculated by the rotational speed control means 21 is the compression of FIG. When the pressure downstream of the receiver tank 50 detected by the pressure sensor 52 is low as indicated by the constant rated power of the machine main body, the calculated rotational speed is high, and the pressure downstream of the receiver tank 50 detected by the pressure sensor. Rotational speed calculated as increases gradually decreases, the rotation speed of the engine 80 varies along the rated power constant linear.

  When the maximum rotational speed of the engine 80 is stored in the storage means 25, the rotational speed control means 21 compares the calculated rotational speed with the stored maximum rotational speed of the engine 80. The engine 80 is controlled so that the engine speed becomes any low speed. FIG. 4 shows a line with a constant rated power and a line with the maximum number of revolutions of the engine 80, and each line intersects the pressure detected by the pressure sensor 52 at the first pressure.

  When the pressure downstream of the receiver tank 50 detected by the pressure sensor 52 is lower than the first pressure, the calculated rotation speed is compared with the stored maximum rotation speed of the engine 80, and the highest engine 80 pressure is detected. Since the rotational speed is low, the rotational speed of the engine 80 detected by the rotational speed sensor 53 is compared with the maximum rotational speed of the engine 80 so that the engine 80 is operated at the maximum rotational speed. When the rotational speed detected by the sensor 53 is lower than the maximum rotational speed of the engine 80, a control signal for increasing the amount of fuel supplied per unit time to the engine 80 is transmitted to the fuel supply device 81, and the rotational speed sensor 53 is compared with the maximum rotational speed of the engine 80, and the rotational speed detected by the rotational speed sensor 53 is When higher than the high rotational speed, it transmits a control signal to decrease the amount of fuel supplied per unit time with respect to the engine 80 to the fuel supply device 81.

  When the pressure downstream of the receiver tank 50 detected by the pressure sensor 52 is higher than the first pressure, the calculated rotational speed is compared with the stored maximum rotational speed of the engine 80 to compare the above-described calculated rotational speed. Since the calculated rotational speed is low, the rotational speed of the engine 80 detected by the rotational speed sensor 53 is compared with the calculated rotational speed so that the engine 80 is operated at the calculated rotational speed. When the rotational speed detected by the rotational speed sensor 53 is lower than the calculated rotational speed, a control signal for increasing the amount of fuel supplied per unit time to the engine 80 is transmitted to the fuel supply device 81. The rotation speed of the engine 80 detected by the rotation speed sensor 53 is compared with the calculated rotation speed, and the rotation speed detected by the rotation speed sensor 53 is compared with the calculated rotation speed. When higher than numbers, it transmits the control signal to decrease the amount of fuel supplied per unit time with respect to the engine 80 to the fuel supply device 81 (rotation speed control).

  On the consumption side, when the pressure downstream of the receiver tank 50 becomes equal to or higher than the high set discharge pressure value set by the operation of the change-over switch 11a because the consumption of compressed air is stopped or the consumption is reduced, the pressure sensor The operation signal output means 24 of the electronic control unit 20 that has received the detection signal from 52 outputs an operation signal for opening the electromagnetic valve 37 provided in the control line 90, and the control line 90 open. Accordingly, compressed air downstream of the receiver tank 50 is introduced into the unloader regulator 32, and the unloader regulator 32 throttles or closes the suction port 61 of the compressor main body 60 by the introduced compressed air (suction control).

  Further, when the pressure downstream of the receiver tank 50 detected by the pressure sensor 52 rises above the “high pressure” set discharge pressure value set by the changeover switch 11 a, the speed control means 22 of the electronic control unit 20 is applied to the engine 80. A control signal for reducing or minimizing the supply amount of fuel per unit time is transmitted to the fuel supply device 81 to shift the engine to low speed operation (speed control).

  On the other hand, when “low pressure” is set by the operation of the changeover switch 11a, a setting signal is transmitted to the electronic control unit 20 by the operation of the changeover switch 11a.

  Thus, after the changeover switch 11a is switched to “low pressure”, the operation of the rotation speed control means 21 provided in the electronic control device is the operation of the rotation speed control when the above-described changeover switch 11a is switched to “high pressure”. When the pressure downstream of the receiver tank 50 is lower than the set discharge pressure value by comparing with the set discharge pressure value set by the pressure setting means 11 including the changeover switch 11a and the like, the The number of revolutions of the engine 80 for operating the compressor main body 60 with rated power is calculated from the pressure detected by the pressure sensor 52, and the fuel supply device is configured so that the number of revolutions of the engine 80 becomes the above-described calculated number of revolutions. A control signal is transmitted to 81. In the case where the maximum rotational speed of the engine 80 is stored in the storage means 25, the calculated rotational speed is compared with the stored maximum rotational speed of the engine 80, so that any one of the low rotational speeds is obtained. A control signal is transmitted to the fuel supply device 81 so that the rotational speed of the engine 80 becomes the same. In FIG. 4, the low pressure set by the changeover switch 11a is the first pressure at which the line with the constant rated power and the line with the maximum rotational speed of the engine 80 intersect, so the rotational speed of the engine 80 is constant with the rated power. Does not drop along the line.

  On the consumption side, the pressure downstream of the receiver tank 50 is equal to or higher than the low set discharge pressure value (first pressure) set by the operation of the changeover switch 11a because the consumption of compressed air is stopped or the consumption is reduced. Then, the actuation signal output means 24 of the electronic control unit 20 that has received the detection signal from the pressure sensor 52 outputs an actuation signal for opening the solenoid valve 37 provided in the control line 90. The control line 90 is opened. Accordingly, compressed air downstream of the receiver tank 50 is introduced into the unloader regulator 32, and the unloader regulator 32 restricts or closes the suction port 61 of the compressor main body 60 by the introduced compressed air.

  Further, when the pressure downstream of the receiver tank 50 detected by the pressure sensor 52 rises above the “low pressure” set discharge pressure value set by the changeover switch 11a, the speed control means 22 of the electronic control unit 20 causes the engine 80 to A control signal for decreasing or minimizing the amount of fuel supplied per unit time is transmitted to the fuel supply device 81 to shift the engine 80 to low speed operation (speed control).

  Thus, for example, the pressure of the compressed fluid discharged from the compressor main body 60 and the rotation of the engine 80 in which the power of the compressor main body is previously reduced by a predetermined margin with respect to the engine output curve within the engine output curve range. Or a correspondence relationship between the pressure of the compressed fluid discharged from the compressor body 60 and the rotational speed of the engine 80 for operating the compressor body 60 at a constant rated power. Storing the preset discharge pressure value of the compressor main body 60 within a predetermined range, and storing the pressure when the pressure of the compressed fluid discharged from the compressor main body 60 is lower than the set discharge pressure value. On the basis of the pressure of the compressed fluid discharged from the compressor body 60, the rotational speed of the engine 80 for operating the compressor body 60 with rated power is calculated, and the rotational speed of the engine 80 is calculated. The set discharge pressure value of the compressed air discharged from the compressor body 60 driven by the engine 80 is changed by controlling the amount of fuel supplied to the engine 80 per unit time so as to be the rotational speed. In addition, when the set discharge pressure value of the compressor main body is reduced, the discharge amount of compressed air increases due to the increase in the rotation speed, and extremely efficient work can be performed.

[Modification]
The configuration example of the engine-driven compressor of the present invention has been described above with reference to FIG. 1, but the drive control device of the present invention is not limited to the configuration of the embodiment shown in FIG. As shown in FIG. 5 described below, it can be modified.

  In the above embodiment described with reference to FIG. 1, the case has been described in which the set discharge pressure value set by the pressure setting means 11 is set to two kinds of pressures, high pressure and low pressure. May be set to three or more types, for example, low pressure, high pressure, and intermediate pressure, or the pressure may be changed steplessly, and is limited to the above-described embodiments. Not.

  In the embodiment shown in FIG. 5, the pressure of the compressed air discharged from the engine-driven compressor can be changed in multiple stages as described above. Instead of the changeover switch 11a in FIG. It is provided as setting means 11.

  Further, in the embodiment shown in FIG. 1, the suction control means 30 provided at the suction port of the compressor body 60 includes an unloader regulator 32 that operates using compressed air downstream of the receiver tank 50 as an operating pressure. However, in the embodiment shown in FIG. 5, the suction port 31 of the compressor main body 60 is configured to be electrically opened and closed instead of this configuration.

  In the embodiment shown in FIG. 5, the suction control means 30 operates a butterfly valve 31 that opens and closes the suction port 61 of the compressor body 60 and other valve bodies 31 ′ by an actuator 32 ′ such as a solenoid or a linear motor. Thus, upon reception of the detection signal from the pressure sensor 52 that detects the pressure of the compressed air discharged from the compressor body 60, the electronic control unit 20 causes the actuator 32 ′ to respond to the pressure indicated by the received detection signal. An operation signal for operating these in response to the pressure is output to control opening and closing of the suction port of the compressor body.

  In the engine-driven compressor provided with the drive control device 1 configured as described above, the pressure setting volume 11b is operated to set the set discharge pressure value to, for example, the low pressure (first pressure) and the high pressure in FIGS. If the pressure is set to an arbitrary pressure, the operation of the rotation speed control means 21 of the electronic control unit 20 is the same as the rotation speed control operation when the changeover switch 11a is switched to “high pressure” or “low pressure”. Yes, when the pressure downstream of the receiver tank 50 rises above the discharge pressure (first pressure) between the low pressure and the high pressure set as the set discharge pressure value by operating the pressure setting volume 11b, the operation of the electronic control unit 20 The signal output means 24 outputs an operation signal for opening the valve body 31 ′ to the actuator 32 ′ of the suction control means 30, and throttles or closes the suction port 61 of the compressor body 60. . Further, when the pressure downstream of the receiver tank 50 rises to a value equal to or higher than the set discharge pressure value set by the pressure setting volume 11b, the speed control means 22 of the electronic control unit 20 sets the fuel supply amount per unit time to the engine 80. A control signal to be reduced or minimized is transmitted to the fuel supply device 81, and the engine 80 is shifted to a low speed operation.

  In the engine drive type compressor provided with the drive control device 1 configured as described above, the compressed air supplied from the engine drive type compressor can be set by the pressure setting volume 11b in multiple stages or continuously. It is possible to set the pressure.

  The drive control apparatus of the present invention described with reference to FIGS. 1 to 5 is an oil-cooled engine drive type that uses oil for sealing and cooling the working space of the compressor body in the illustrated examples. Although shown as what is provided in a compressor, the engine drive type compressor 1 in which the drive control apparatus 1 of this invention is provided is not limited to the thing provided with the receiver tank 50 and the oil cooler 58, For example, a compressor main body The present invention can be applied to, for example, an oil-free screw compressor or the like that does not require cooling oil or the like for sealing and cooling the working space 60 and therefore does not require the receiver tank 50 or the oil cooler 58.

  Thus, when the drive control device of the present invention is provided in an engine-driven compressor that does not include the receiver tank 50 or the like, for example, a control pipe that communicates between the discharge side of the compressor body 60 and the unrotor regulating radar 32. A pressure sensor 52 is provided in the discharge pipe connected in the passage 90 or downstream of the compressor body 60.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic explanatory drawing of the engine drive type compressor provided with the drive control apparatus of this invention. The functional block diagram of an electronic control apparatus. The graph which shows the power performance of an engine output curve and a compressor main body. The graph showing the relationship between the pressure which a pressure sensor detects, and the rotation speed which the rotation speed control means calculated. BRIEF DESCRIPTION OF THE DRAWINGS Schematic explanatory drawing of the engine drive type compressor provided with the drive control apparatus of this invention. The graph for demonstrating the control range of the rotation speed of an engine. The graph for demonstrating the relationship between the rotation speed of an engine and the motive power of a compressor main body. The schematic explanatory drawing of the engine drive type compressor provided with the conventional drive control apparatus. The graph which shows the output curve of the conventional engine, and the power performance of a compressor main body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drive control device 11 Pressure setting means 11a Changeover switch 11b Pressure setting volume 20 Electronic control device 21 Rotational speed control means 22 Speed control means 23 Speed control means 24 Actuation signal output means 25 Storage means 30 Suction control means 31 Open / close valve 31 'valve Body 32 Unloader regulator 32 'Actuator 40' Pressure regulator 50 Receiver tank 52 Pressure sensor 53 Speed sensor 58 Oil cooler 60 Compressor body 61 Suction port 70 Speed regulator 80 Engine 81 Fuel supply device 85 Governor lever 90 Control line 91, 92 Branch Pipeline

Claims (11)

In an engine-driven compressor that drives an engine with a compressor body that introduces and compresses a fluid to be compressed,
When the discharge pressure of the compressor body is set as a preset discharge pressure value in a predetermined range in advance, and when the pressure of the compressed fluid discharged from the compressor body is lower than the set discharge pressure value,
Within the range of the engine output curve, the engine speed decreases as the pressure of the compressed fluid discharged from the compressor body increases, and the engine rotates as the pressure of the compressed fluid discharged from the compressor body decreases. A method for changing the discharge pressure of an engine-driven compressor, wherein the number is increased.   The range of the set discharge pressure value is within the range of the set maximum pressure and the set minimum pressure, and the engine speed is within the engine speed range excluding the range of the engine full load speed and the no-load maximum speed. The method for changing the discharge pressure of the engine-driven compressor according to claim 1 to be controlled.   A correspondence relationship between the pressure of the compressed fluid discharged from the compressor main body having a power lower than the output curve of the engine by a predetermined margin and the engine speed is obtained in advance, and the compressor is determined based on the correspondence relationship. 3. The method for changing the discharge pressure of an engine-driven compressor according to claim 1, wherein the engine speed is calculated from the pressure of the compressed fluid discharged from the main body.   The engine speed is reduced by reducing the amount of fuel supplied to the engine per unit time when the pressure of the compressed fluid discharged from the compressor body is equal to or higher than the set discharge pressure value. Item 4. A method for changing discharge pressure of an engine-driven compressor according to any one of Items 1 to 3.   5. The suction port of the compressor main body is throttled or closed when the pressure of the compressed fluid discharged from the compressor main body is equal to or higher than the set discharge pressure value. A method for changing the discharge pressure of an engine-driven compressor. In an engine-driven compressor that drives an engine with a compressor body that introduces and compresses a fluid to be compressed,
When the discharge pressure of the compressor body is set as a preset discharge pressure value in a predetermined range in advance, and when the pressure of the compressed fluid discharged from the compressor body is lower than the set discharge pressure value,
Within the range of the engine output curve, the engine speed decreases as the pressure of the compressed fluid discharged from the compressor body increases, and the engine rotates as the pressure of the compressed fluid discharged from the compressor body decreases. An engine-driven compressor provided with a drive control device for increasing the number.   The drive control device stores in advance a correspondence relationship between the pressure of the compressed fluid discharged from the compressor main body of the power that is lower by a predetermined margin than the output curve of the engine and the rotational speed of the engine. The engine-driven compressor according to claim 6, wherein the engine speed is calculated from the pressure of the compressed fluid discharged from the compressor body based on the compressor. The drive control device includes: a pressure setting unit that sets a discharge pressure of the compressor body as a set discharge pressure value within a predetermined range; a pressure detection unit that detects a pressure of a compressed fluid discharged from the compressor body; A rotational speed detection means for detecting the rotational speed, a fuel supply device for controlling the amount of fuel supplied to the engine in response to the received control signal, and an electronic control device for transmitting a control signal to the fuel supply device; With
The electronic control device includes storage means for storing a correspondence relationship between the pressure of the compressed fluid discharged from the compressor body and the engine speed, and the pressure detected by the pressure detection means is set by the pressure setting means. When the pressure is lower than the set discharge pressure value, the engine speed is calculated from the pressure detected by the pressure detecting means based on the correspondence stored in the storage means, and the rotation detected by the speed detecting means is detected. 8. The engine-driven compressor according to claim 7, further comprising a rotation speed control means for transmitting a control signal to the fuel supply device so that the number becomes the calculated rotation speed.   The rotation speed control means transmits a control signal for increasing the amount of fuel supplied per unit time to the engine to the fuel supply device when the rotation speed detected by the rotation speed detection means is lower than the calculated rotation speed. A control signal for reducing the amount of fuel supplied per unit time to the engine is transmitted to the fuel supply device when the rotational speed detected by the rotational speed detection means is higher than the calculated rotational speed. Item 9. The engine-driven compressor according to Item 8.   The electronic control unit further controls to reduce the amount of fuel supplied to the engine per unit time when the pressure detected by the pressure detection unit is equal to or higher than the set discharge pressure value set by the pressure setting unit. 10. The engine-driven compressor according to claim 8, further comprising speed control means for transmitting a signal to the fuel supply device to reduce the engine speed. In response to the received control signal, a suction control means for restricting or closing the suction port of the compressor body is provided,
The electronic control device further provides an operation signal for restricting or closing the suction port of the compressor body when the pressure detected by the pressure detection means is equal to or higher than the set discharge pressure value set by the pressure setting means. The engine-driven compression according to any one of claims 8 to 10, further comprising an operation signal generating means that transmits to the suction control means and reduces or stops introduction of a fluid to be compressed into the compressor body. Machine.

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