JP4692126B2 - Flow rate measuring device and flow rate measuring method - Google Patents

Description

  The present invention relates to a flow rate measuring device and a flow rate measuring method for measuring a flow rate of a fluid, and more particularly to a flow rate measuring device and a pressure flow rate measuring method for measuring a flow rate of a pressure fluid.

  Conventionally, the flow rate of a fluid is measured by measuring, for example, a pressure change (differential pressure type flow meter) generated by an obstruction placed in the flow or a temperature change generated by the flow (hot wire type flow meter). It was. However, these are intended for low-pressure fluids, and the measurement of the flow rate of a high-pressure fluid has a problem with pressure resistance and cannot be used. Therefore, for example, when handling a high-pressure fluid of 100 MPa or more like an injector used in a diesel engine, the flow rate of the fluid is measured after being injected from the injector, that is, after becoming a low-pressure fluid. Was measured (see Patent Document 1).

  However, when the flow rate is measured after the injection, various errors such as an error due to a temperature change before and after the injection or an error due to leakage of each part accumulate, and the measurement accuracy may be reduced.

JP 2000-321110 A

  In view of the conventional problems, an object of the present invention is to provide a flow rate measuring device and a flow rate measuring method that can measure the flow rate of a pressure fluid.

In order to achieve the above object , a flow rate measuring apparatus according to one aspect of the present invention is a flow rate measuring apparatus for measuring a flow rate of a fluid ejected from an inspection object (10) according to claim 1, (2) and a piston (23) having a front piston rod (24) disposed in the front chamber (21a) and a rear piston rod (25) disposed in the rear chamber (21b). ) In the cylinder (2) to pressurize the fluid with the front piston rod (24) to form a pressure fluid, the front chamber (21a) and the rear chamber (21b) and a working fluid supply section (3) capable of supplying a working fluid for moving the piston in the cylinder (2), and a pressure accumulating section for storing the pressure fluid supplied from the pressure increasing section (2). 4) and the position of the piston The amount of the working fluid is controlled so as to keep the pressure of the position measuring unit (7) to measure and the pressure accumulating unit (4) constant, and the piston of the piston measured by the position measuring unit (7) is controlled. A fluid control unit (11) for controlling a flow rate of the pressure fluid supplied from the pressure increasing unit (2) to the pressure accumulating unit (4) by controlling a supply amount of the working fluid according to a position; An ejection control unit (8) that controls ejection of the pressure fluid from the inspection object (10), and a flow rate calculation unit (15) that calculates the flow rate of the ejected pressure fluid, from the inspection object (10) When the pressure fluid is ejected, the flow rate calculation unit (15) is configured to generate the pressure increase unit (15) based on the movement amount of the piston calculated from the position information of the piston measured by the position measurement unit (7). 2) to the pressure accumulator (4) That determine the flow rate of the pressure fluid, by correcting on the basis of the flow amount to a predetermined correction coefficient, characterized by measuring the flow rate of the fluid to be ejected from said object (10).

  Therefore, the flow rate ejected from the inspection object can be obtained based on the flow rate before the ejection, and the flow rate of the pressure fluid can be measured with high accuracy.

  Furthermore, as described in claim 2, the flow rate calculation unit (15) creates a correction coefficient based on the temperature and pressure measured by the pressure measurement unit (5) and the temperature measurement unit (6). Can do. In this way, the correction coefficient can be accurately calculated, and an accurate flow rate can be obtained.

A flow rate measuring method according to another aspect of the present invention is a flow rate measuring method according to claim 3 , wherein the fluid stored in the pressure accumulating portion is ejected from the inspection target and the flow rate of the ejected fluid is measured. (2) and a piston (23) having a front piston rod (24) disposed in the front chamber (21a) and a rear piston rod (25) disposed in the rear chamber (21b) Or a pressure increasing step of forming a pressure fluid by pressurizing the fluid with the front piston rod (24) by supplying the working fluid to the rear chamber (21b) and moving it in the cylinder (2). And an accumulating step for storing the pressure fluid in the accumulator, and a supply amount of the working fluid so that the pressure fluid is ejected from the test object and the pressure of the accumulator (4) is kept constant. And controlling the supply amount of the working fluid in accordance with the position of the piston, thereby ejecting and supplying the pressure fluid to the pressure accumulating unit, and changing the flow rate of the pressure fluid to the position of the piston. And a flow rate calculating step for determining the flow rate of the ejected fluid by correcting the flow rate based on a predetermined correction coefficient.

  Therefore, the flow rate ejected from the inspection object can be obtained based on the flow rate before the ejection, and the flow rate of the pressure fluid can be measured with high accuracy.

Furthermore, as described in claim 4 , the correction coefficient can be created based on the pressure and temperature of the pressure fluid, and high-precision correction can be performed.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a flow rate measuring device 1 of the present embodiment. In FIG. 1, for easy understanding, the fluid circuit is indicated by a solid line and the signal circuit is indicated by a broken line.

  The flow rate measuring device 1 connects the test object 10 to the pressure accumulating unit 4, causes a pressure test fluid that is a high-pressure test fluid, that is, a pressure fluid, to be ejected from the test object 10, and measures the flow rate ejected from the test object 10. is there. In this embodiment, the test object 10 is an injector for fuel injection of a diesel engine, and the pressure test fluid ejected from the test object 10 is a test oil equivalent to light oil.

  The inspection object 10 connected to the pressure accumulating unit 4 of the flow rate measuring device 1 is driven by a control signal from the ejection control unit 8 and ejects the pressure test fluid. Specifically, in order to eject the pressure test fluid, the ejection control unit 8 applies an injector injection pulse to the injection control electromagnetic valve of the injector. In addition, the number of injections or the injection time can be appropriately determined according to the inspection object and the measurement purpose.

  Further, the flow rate measuring device 1 includes a pressure increasing unit 2 for storing the pressure test fluid in the pressure accumulating unit 4, and the test fluid supplied from the test fluid supplying unit 9 is supplied via the check valve 41 to the pressure increasing unit. Take in 2. Thereafter, the pressure is increased and supplied to the pressure accumulating unit 4 via the check valve 42. In the present embodiment, the pressure increasing portion 2 has a cylinder including a large diameter cylinder portion 21 and a small diameter cylinder portion 22. The large-diameter cylinder portion 21 is provided with a piston 23. By supplying a working fluid to the front chamber 21a or the rear chamber 21b of the large-diameter cylinder portion 21 divided forward and backward by the piston 23, the piston 23 slides back and forth. Moving.

  The piston 23 is provided with a front piston rod 24 extending to the small diameter cylinder portion 22 and a rear piston rod 25 provided at the rear portion. The front piston rod 24 advances to pressurize the inspection fluid taken into the small diameter cylinder portion 21. The pressurized test fluid is supplied to the pressure accumulator 4 through the check valve 42 as a pressurized test fluid. The position measuring unit 7 can determine the position of the piston 23 by measuring the position of the rear piston rod 25. The amount of movement of the piston can also be calculated from the position of the moved piston before and after the movement.

  The working fluid for operating the piston 23 of the pressure increasing unit 2 is supplied from the working fluid supply unit 3. In the working fluid supply unit 3, the working fluid is supplied from the working fluid storage unit 31 to the switching valve 35 by the piston pump 32 driven by the motor 32, and the switching valve 35 is electromagnetically switched, so that the pressure increasing unit 2 is switched. Supply. Normally, the working fluid is oil.

  The switching valve 35 has three switching positions. In the neutral position 35b, all the valves are closed, and no working fluid is supplied to the cylinder. At the retracted position 35a, the working fluid flows into the rear chamber 21b of the large-diameter cylinder portion 21 and returns from the front chamber 21a to the working fluid storage portion 31. As a result, the piston 23 moves backward, and the inspection fluid is taken into the small diameter cylinder portion 22. At the forward movement position 35c, the direction of the working fluid flow is opposite to that of the backward movement position 35a, and the working fluid flows into the front chamber 21a of the large-diameter cylinder section 21 and returns from the rear chamber 21b to the working fluid storage section 31. As a result, the piston 23 moves forward, pressurizes the inspection fluid taken into the small-diameter cylinder portion 22 and supplies it to the pressure accumulating portion 4. The relief valve 36 opens when the pressure of the working fluid becomes too high, and returns the working fluid to the working fluid reservoir 31.

  The fluid control unit 11 monitors the pressure of the pressure accumulating unit 4 with the pressure measuring unit 5 and controls the opening of the switching valve 35 of the working fluid supply unit 3 so that the pressure accumulating unit 4 maintains a predetermined pressure. The opening degree of the switching valve 35 of the working fluid supply unit is controlled according to the position of the piston obtained by the position measurement unit 7. Since the volume occupied by the test fluid changes with the piston position, and the speed of the pressure change varies with the piston position, control of the piston position changes the supply amount of the test fluid according to the piston position. Even if the speed is high, the predetermined pressure is quickly followed. The fluid control unit 11 opens the switching valve 35 of the working fluid supply unit so that the pressure accumulating unit 4 maintains a predetermined pressure even when the pressure test fluid in the pressure accumulating unit 4 is ejected through the test object 10. And the test fluid is supplied to the pressure accumulating unit 4. The above-described control based on the piston position is effective in such a sudden pressure change state.

  The flow rate calculating unit 15 calculates the flow rate of the test fluid supplied from the pressure increasing unit 2 to the pressure accumulating unit 4 from the movement amount of the piston 23, and this is a correction coefficient that is a compression rate determined by the temperature and pressure of the pressure accumulating chamber 4. The flow rate ejected from the inspection object 10 is calculated by correcting by the above. The measurement values input to the flow rate calculation unit 15 are the position information of the piston 23 and the output values from the pressure measurement unit 5 and the temperature measurement unit 6 that measure the pressure and temperature of the pressure accumulation chamber 4. The movement amount of the piston 23 is calculated from information on the initial position and the movement end position of the piston 23. The obtained ejection flow rate is displayed and recorded by an appropriate display device or recording device (not shown).

  2A and 2B are diagrams for explaining the principle of flow rate calculation according to this embodiment. In FIG. 2A, it is assumed that the cylinder 50 including the piston 60 and the piston rod 61 is filled with fluid, and the pressure in the cylinder 50 is maintained at a predetermined high pressure.

  Next, the fluid in the cylinder 50 flows out through the outlet 53. In this case, the fluid pressure is monitored by the pressure gauge 82, and the piston is moved by the pressure control unit 70 so as to maintain the fluid pressure at a predetermined high pressure. In the present embodiment, the total volume at a high pressure changes depending on the piston position, and the required compression amount also changes. As described above, the movement of the piston is also controlled according to the position of the piston. As shown in FIG. 2B, when the movement amount ΔL of the piston when the fluid outflow stops, the sectional area of the piston is S, the volume of the fluid flowing out is obtained as ΔLS, and the outflow flow rate is obtained. .

  However, when the fluid is a high-pressure fluid, the compression rate or expansion rate related to the pressure P or the temperature T cannot be ignored. In the present invention, the flow rate is corrected in consideration of pressure and temperature. In the present embodiment, a correction coefficient k (p, T) indicating the compression rate is created by actual measurement and stored in the flow rate measurement unit as a correction table. At this time, the flow rate Q is obtained as follows.

Q = ΔLS / k (p, T)
In the present embodiment, the correction coefficient that is the compression rate is obtained by actual measurement, but can also be obtained by calculation or simulation.

  The operation of this embodiment will be described below based on the flowchart of FIG.

  First, in step S <b> 1, the injector that is the inspection object 10 is coupled to the pressure accumulator 4. When the injector is used in a production line for mass production, the injector carried on the pallet is automatically coupled to the pressure accumulating unit 4. Next, the injector is electrically connected to the ejection control unit 8 and can be driven by a signal from the ejection control unit 8.

  In step S <b> 2, the working fluid is supplied to the front portion 21 b of the large diameter cylinder portion 21 of the pressure increasing portion 2, the piston 23 is retracted, and the inspection fluid from the inspection fluid supply portion 9 is taken into the small diameter cylinder portion 22. Note that step S2 can be performed simultaneously with or before step S1.

  Next, in step S3, the working fluid is supplied to the rear portion 21a of the large-diameter cylinder portion 21 of the pressure increasing portion 2, the working fluid in the front portion 21b is discharged, and the piston 23 is advanced. The inspection fluid in the small-diameter cylinder part 22 is pressurized to 180 MPa in the predetermined high pressure embodiment, and is sent to the pressure accumulating part 4 as a pressure inspection fluid. In the pressure accumulating unit 4, the pressure of the pressure accumulating unit 4 is monitored by the pressure measuring unit 5, and the opening degree of the switching valve 35 of the working fluid supply unit 3 is controlled by the fluid control unit 11 so as to maintain 180 MPa.

  In step S <b> 4, the ejection control unit 8 applies an injector injection pulse to the injection control electromagnetic valve of the injector that is the inspection object 10 so as to cause fuel injection, and ejects light oil that is the inspection fluid.

  At the same time, in step S5, the fluid control unit 11 maintains the pressure of the pressure accumulating unit 4 at 180 MPa and supplies a supply amount corresponding to the piston position measured by the position measuring unit 7. The opening degree of the three switching valves 35 is controlled. Therefore, the piston 23 of the pressure increasing unit 2 moves forward quickly, supplies the pressure test fluid to the pressure accumulating unit 4, and keeps the pressure of the pressure accumulating unit 4 constant. Thus, since the piston 23 moves forward rapidly so as to maintain the pressure in the pressure accumulating portion at 180 MPa, the pressure is supplied to the pressure accumulating portion 4 quickly and accurately by the amount of the ejected test fluid.

  In step S6, the flow rate calculation unit 15 obtains the piston movement amount ΔL from the change in the position measured by the position measurement unit 7, that is, the difference between the movement start position and the movement end position, and the movement amount ΔL and the cross-sectional area of the cylinder are obtained. The volume ΔLS of the inspection fluid is obtained from S.

  In step S7, a correction coefficient which is a compression rate is obtained from a correction coefficient table created in advance based on the pressure obtained by the pressure measurement unit 5 and the temperature obtained by the temperature measurement unit 6, and the ejection volume ΔLS of the inspection fluid is corrected. The flow rate of the inspection fluid is obtained.

  As described above, in this embodiment, the movement of the piston of the pressure increasing unit 2 is moved while holding the pressure constant, the position of the piston 23 of the pressure increasing unit 2 is measured, and the flow rate of the pressure fluid is obtained. By correcting the flow rate with the compression rate obtained based on the temperature and pressure of the pressure test fluid, the ejection flow rate of the pressure test fluid can be measured on the upstream side, and highly accurate flow rate measurement is possible. Furthermore, since the movement of the piston of the pressure intensifying unit 2 is controlled so that the flow rate to be supplied is appropriate according to the piston position, there is no delay in keeping the pressure constant.

  In the present embodiment, the inspection object is an injector and the inspection fluid is light oil. A general fluid may be used.

It is a figure which shows one Embodiment of the flow measuring device of this invention. (A), (b) is a figure explaining the flow measurement of this embodiment. It is a figure which shows the operation | movement flow of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flow measuring device 2 Pressure increase part 3 Working fluid supply part 4 Pressure accumulation part 5 Pressure measurement part 6 Temperature measurement part 7 Position measurement part 8 Injection control part 9 Inspection fluid supply part 10 Inspection object 11 Fluid control part 15 Flow rate calculation part

Claims (4)

A flow rate measuring device for measuring a flow rate of fluid ejected from an inspection object (10),
A piston (23) having a cylinder (2), a front piston rod (24) disposed in the front chamber (21a), and a rear piston rod (25) disposed in the rear chamber (21b); 23) is moved in the cylinder (2) to pressurize the fluid with the front piston rod (24) to form a pressure fluid; (2)
A working fluid supply section (3) capable of supplying a working fluid for moving a piston in a cylinder (2) to the front chamber (21a) and the rear chamber (21b);
A pressure accumulator (4) for storing the pressure fluid supplied from the pressure intensifier (2);
A position measuring unit (7) for measuring the position of the piston;
The supply amount of the working fluid is controlled so as to keep the pressure of the pressure accumulating section (4) constant, and the supply amount of the working fluid according to the position of the piston measured by the position measurement section (7). and by controlling the fluid control unit for controlling the flow rate supplied said pressurizing portion (2) the accumulator portion of the pressure fluid to (4) (11),
An ejection control unit (8) for controlling ejection of the pressure fluid from the inspection object (10);
A flow rate calculation unit (15) for calculating the flow rate of the jetted pressure fluid,
When the pressurized fluid is ejected from the inspection object (10), the flow rate calculation unit (15) calculates the movement amount of the piston calculated from the position information of the piston measured by the position measurement unit (7). based obtains the flow rate of the pressure fluid supplied to the pressure accumulating section (4) from said pressurizing portion (2), by correcting on the basis of the flow rate to a predetermined correction coefficient, from the test object (10) A flow rate measuring device for measuring a flow rate of a jetted fluid.   A pressure measuring unit (5) that measures the pressure and temperature of the pressure accumulating unit (4); and a temperature measuring unit (6), and the flow rate calculating unit (15) includes the pressure measuring unit (5) and the temperature measuring unit. The flow rate measuring device according to claim 1, wherein the correction coefficient is created based on the temperature and pressure measured by (6). It is a flow rate measuring method for ejecting the fluid stored in the pressure accumulating part from the inspection target and measuring the flow rate of the ejected fluid,
A piston (23) having a cylinder (2), a front piston rod (24) disposed in the front chamber (21a) and a rear piston rod (25) disposed in the rear chamber (21b) is connected to the front chamber ( 21a) or by increasing the pressure in the front piston rod (24) to form a pressure fluid by supplying the working fluid to the rear chamber (21b) and moving the cylinder in the cylinder (2). Steps,
A pressure accumulation step of storing the pressure fluid in the pressure accumulation section; and
While the pressure fluid is ejected from the inspection target, the supply amount of the working fluid is controlled so as to keep the pressure of the pressure accumulating section (4) constant, and the supply amount of the working fluid is determined according to the position of the piston A jet and supply step of supplying the pressure fluid to the pressure accumulating unit by controlling
Calculated based on the flow rate of the pre Ki圧 force fluid to the position of the piston, by correcting on the basis of the flow amount to a predetermined correction coefficient, and having a flow rate calculating step of calculating the flow rate of the fluid to be ejected Flow measurement method.   The flow rate measuring method according to claim 3, wherein the correction coefficient is created based on a pressure and a temperature of the pressure fluid.

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