JP2006105656A - Flow rate measuring device and flow rate measurement method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow rate measuring device and a flow rate measurement method for reducing measurement time and measuring a jetting flow rate precisely. <P>SOLUTION: The flow rate measuring device 10 comprises a housing 12; a pressure sensor 20; a micro syringe 30; and an on/off valve 40. A fuel injection valve 1 is mounted to the housing 12 liquid-tightly. The side of the pressure sensor 20 in a sealed chamber 14 formed inside the housing 12 is filled with a jetted liquid 16, and the space at a side where the fuel injection valve 1 is mounted in the sealed chamber 14 is filled with air 18. The pressure sensor 20 detects a change in the volume of the jetted liquid 16 at the side of the pressure sensor 20 in the sealed chamber 14, in a communicating pipe 100, and in a liquid chamber 26 as a change in pressure. The microsyringe 30 reduces the amount of projection of a piston 36 projecting from a variable capacity chamber 34 each time when the fuel injection valve 1 injects fuel, and increase the volume of the variable capacity chamber 34. When the on/off valve 40 is opened, the boundary surface position between the jetted liquid 16 and air 18 in the sealed chamber 14 is set to an initial position. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a flow rate measuring device and a flow rate measuring method for measuring an ejection flow rate of a liquid ejected by a fluid ejection valve.

As a device for measuring an injection flow rate of a liquid ejected by a fluid injection valve such as a fuel injection valve, a fluid flow rate flowing through a supply passage for supplying an injection liquid to the fluid injection valve is changed to a gear as described in Patent Document 1, for example. What is measured with a type flow meter is known.
It is also conceivable to measure the flow rate of the liquid ejected by the fluid ejection valve by receiving the liquid ejected by the fluid ejection valve in a container and measuring the weight of the ejected liquid.

Japanese Utility Model Publication No. 51-38777

  However, the liquid in the supply passage that is installed upstream of the fluid injection valve and supplies the injection liquid to the fluid injection valve is usually pressurized to the actual injection pressure, and thus the temperature is increased. Since the liquid having a high temperature easily changes in viscosity and specific gravity under the influence of pressure fluctuation or temperature fluctuation, it is difficult to measure the injection flow rate of the fluid injection valve with high accuracy.

Also, when measuring the flow rate of the jet liquid flowing through the supply passage installed upstream of the fluid injection valve, if the gear-type flow meter described above is used as the flow meter, the flow rate of the liquid flowing continuously through the supply passage is measured. Therefore, there is a problem that the measurement time becomes long.
On the other hand, when the liquid ejected by the fluid ejection valve is received by the container and the weight of the ejected liquid is measured downstream of the flow rate ejection valve, the fluid is ejected into the atmosphere at a lower pressure than the upstream side of the fluid ejection valve. Therefore, it is difficult to be affected by pressure fluctuations and temperature fluctuations, and the injected liquid can be directly measured.

However, when a liquid is ejected into the atmosphere, the ejected liquid may evaporate and the weight of the ejected liquid may not be measured with high accuracy. Moreover, it is difficult to measure the weight with high accuracy for a small amount of injection.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a flowmeter side device and a flow rate measurement method that can shorten the measurement time and measure the injection flow rate with high accuracy.

  According to the first to twelfth aspects of the present invention, the fluid injection valve detects a change in the volume of the injection liquid injected into the sealed chamber of the housing. That is, a change in the volume of the ejected liquid ejected by the fluid ejecting valve is detected on the downstream side of the fluid ejecting valve, which has a lower pressure than the upstream side of the fluid ejecting valve and is less susceptible to pressure fluctuations and temperature fluctuations. Therefore, the injection flow rate of the fluid injection valve can be measured with high accuracy from the detected volume change of the injection liquid.

Moreover, since it injects to a sealed chamber, the injected injection liquid is hard to evaporate. Therefore, the volume change of the jet liquid can be detected with high accuracy.
In addition, since the volume change of the injection liquid injected by the fluid injection valve is detected instead of the flow rate of the supply passage supplying the injection liquid to the fluid injection valve, the injection flow rate of the fluid injection valve is increased even if the number of injections is small. It can be measured accurately. Therefore, the measurement time for each fluid injection valve can be shortened.

  According to the second and eighth aspects of the present invention, when liquid is injected into the sealed chamber filled with gas, the gas is compressed by the volume of the injected liquid, and the pressure of the gas increases. By detecting the volume change of the liquid ejected from this gas pressure rise, the ejection flow rate of the fluid ejection valve can be measured. Further, since the liquid is injected into the gas in the sealed chamber, a fluid injection valve in an operating environment that injects the liquid into the gas can be injected in a similar environment. Therefore, the injection flow rate can be measured with high accuracy.

According to the third and ninth aspects of the present invention, since the liquid is ejected into the sealed chamber filled with the liquid that hardly changes in volume by increasing or decreasing the pressure, the volume change of the ejected liquid is detected as the position displacement. Alternatively, it can be detected with high accuracy as a pressure change.
According to the fourth and tenth aspects of the present invention, since the fluid injection valve side of the sealed chamber is filled with gas, the fluid injection valve injects liquid into the gas. Therefore, any fluid injection valve in an operating environment that injects liquid into gas can be injected in a similar environment, so that the flow rate can be measured with high accuracy. In addition, since the other part of the sealed chamber is filled with the liquid, the change in volume of the liquid ejected by the fluid ejection valve into the sealed chamber can be detected as the positional displacement of the liquid in the sealed chamber or as a change in pressure.

  According to the invention described in claim 5 of the present invention, in the configuration of the invention described in claim 4, further comprising an on-off valve for intermittently connecting the atmosphere side and the sealed chamber, and the on-off valve opens to open the sealed chamber. The boundary surface position between the liquid and gas is set to the initial position. According to this configuration, for example, if the on-off valve is opened before measuring each fluid injection valve, the boundary surface between the gas and the liquid in the sealed chamber can be easily set to the initial position.

According to the sixth aspect of the present invention, the fluid injection valve is opened for a predetermined time and the injection amount injected per injection is set as the set injection amount, and only the product of the number of injections of the fluid injection valve and the set injection amount is used. If the volume of the variable volume chamber is increased with the variable volume device, the injection amount of the fluid injection valve can be measured from the change in volume of the liquid detected by the detection means and the set injection amount.
Further, the volume change amount of the ejection liquid detected by the detection means is the difference between the product of the number of injections of the fluid injection valve and the set injection quantity and the flow rate actually injected by the fluid injection valve. The volume change amount of the ejected liquid is small. Therefore, the volume change of the jetted liquid can be detected with high accuracy by the high-precision detection means for detecting a minute volume change.

According to the twelfth aspect of the present invention, when the fluid injection valve opens for a predetermined time and the injection amount injected per time is set as the set injection amount, and the fluid injection valve injects a plurality of times, Since the volume of the space communicating with the chamber is increased by the product of the number of injections and the set injection amount, the detected volume change amount of the injection liquid is actually the product of the number of injections of the fluid injection valve and the set injection amount. It becomes a difference from the flow rate injected by the fluid injection valve. Accordingly, the injection flow rate of the fluid injection valve can be measured from the detected volume change of the injection liquid and the set injection amount.
In addition, since the volume change amount of the jetted liquid to be detected becomes small, it is possible to detect the volume change of the liquid with high accuracy using a high-accuracy detection unit that detects a minute volume change.

Hereinafter, one embodiment of a flow measuring device of the present invention is described based on figures.
As shown in FIG. 1, the flow rate measuring device 10 includes a housing 12, a pressure sensor 20, a microsyringe 30, and an on-off valve 40. The fuel injection valve 1 that is a fluid injection valve is, for example, an electromagnetically driven fuel injection valve that injects fuel into a combustion chamber of an internal combustion engine. The fuel injection valve 1 is attached to the housing 12 in a liquid-tight manner.

The housing 12 forms a sealed chamber 14 therein. The pressure sensor 20 side of the sealed chamber 14 is filled with the injection liquid 16, and the space on the side of the sealed chamber 14 where the fuel injection valve 1 is attached is filled with air 18.
The pressure sensor 20 as a detection means has a housing 22 and a diaphragm 24. A space in the housing 22 is separated into a liquid chamber 26 and an atmospheric chamber 28 by a diaphragm 24. The liquid chamber 26 communicates with the sealed chamber 14 via the communication pipe 100, and the inside of the communication pipe 100 and the liquid chamber 26 are filled with the jet liquid 16 as in the pressure sensor 20 side of the sealed chamber 14. The pressure sensor 20 detects the volume change of the jet liquid in the pressure sensor 20 side of the sealed chamber 14, the communication pipe 100, and the liquid chamber 26 as a pressure change due to the displacement of the diaphragm 24, and the pressure signal is electronically controlled ( ECU) 50.

  The microsyringe 30 that is a variable volume device has a housing 32 and a piston 36 that is slidably supported by the housing 32, and is attached to the housing 12 through the peripheral wall of the housing 12. The housing 32 forms a variable volume chamber 34 that communicates with the sealed chamber 14. One end of the piston 36 protrudes into the variable volume chamber 34, and the other end of the piston 36 is connected to a servo motor (not shown). The amount by which the piston 36 protrudes into the variable volume chamber 34 is controlled by a servo motor.

The on-off valve 40 is installed in the atmosphere-side open pipe 102 opened to the atmosphere side and the sealed chamber 14. As the on-off valve 40 opens and closes, the communication between the sealed chamber 14 and the atmosphere side is interrupted.
The ECU 50 as the measuring means controls the drive current supplied to the coil 2 of the fuel injection valve 1 and controls the opening and closing of the fuel injection valve 1. Further, the ECU 50 measures the volume change of the injected liquid injected into the sealed chamber 14 based on the pressure signal received from the pressure sensor 20, that is, the flow rate of the injected liquid injected from the fuel injection valve 1. The ECU 50 controls the servo motor to adjust the protruding amount of the piston 36 of the microsyringe 30.

Next, a method for measuring the flow rate of the fuel injection valve 1 by the flow rate measuring device 10 will be described.
(1) First, the servo motor is controlled to cause the piston 36 to protrude into the variable volume chamber 34 by a predetermined amount.
(2) The fuel injection valve 1 is attached to the housing 12.
(3) Open the on-off valve 40 and open the sealed chamber 14 to the atmosphere. As a result, the jet liquid sprayed into the sealed chamber 14 during the previous measurement is discharged from the atmosphere open pipe 102 to the atmosphere side. The initial position is set to open in the sealed chamber 14. When the flow of the jet liquid 16 flowing out from the atmosphere opening pipe 102 to the atmosphere side stops, the on-off valve 40 is closed.

(4) The ECU 50 sends to the fuel injection valve 1 a pulse signal for injecting a predetermined number of times with the same injection time width. At this time, the ECU 50 presets and stores the injection amount that the fuel injection valve 1 injects once, and the volume of the variable volume chamber 34 becomes the set injection amount every time the fuel injection valve 1 injects once. The piston 36 is moved in the left direction in FIG. 1 by controlling the servo motor so as to increase only the amount of protrusion of the piston 36 protruding into the variable volume chamber 34.

(5) When the fuel injection valve 1 injects the predetermined number of times and stops the injection, the ECU 50 changes the pressure signal detected by the pressure sensor 20 as the fuel injection valve 1 injects the injection liquid into the sealed chamber 14 the predetermined number of times. Is recognized as a pressure change ΔP.
Here, by moving the piston 36 during the injection, the volume of the variable volume chamber 34 is increased by the product Q × N of the set injection amount Q and the number of injections N, so the total injection of the fuel injection valve 1 If the amount is equal to the product Q × N of the set injection amount Q and the number N of injections, the pressure change ΔP in the sealed chamber 14 should be zero. If the total injection amount of the fuel injection valve 1 and Q × N are not equal, the pressure of the air 18 in the sealed chamber 14 increases or decreases due to the difference. By the increase / decrease of the pressure of the air 18, the pressure of the jet liquid 16 in the sealed chamber 14, the communication pipe 100, and the liquid chamber 26 is increased / decreased. The pressure sensor 20 detects an increase or decrease in the pressure of the jet liquid 16 as a pressure change ΔP.
(6) Then, the ECU 50 calculates the total injection amount N times of the fuel injection valve 1 from the pressure change ΔP after N times of injection, that is, the volume change of the injection liquid after N times of injection and the set injection amount. The injection flow rate per time of the fuel injection valve 1 is measured.

In the flow rate measuring device 10 of the present embodiment described above, the fuel injection valve 1 injects the injection liquid into the air in the sealed chamber 14, and therefore the intake pipe or the combustion chamber in which the fuel injection valve 1 actually injects fuel, The environment is similar. Further, not the flow rate of the pressurized injection liquid upstream of the fuel injection valve 1, but the volume change of the injection liquid injected into the air by the fuel injection valve 1 on the downstream side of the fuel injection valve 1 is measured. It is hardly affected by pressure fluctuation and temperature fluctuation. Furthermore, since the injection liquid is injected into the sealed chamber 14, evaporation of the injection liquid can be prevented. Therefore, the flow rate of the injection liquid injected by the fuel injection valve 1 can be measured with high accuracy.
Moreover, in the said embodiment, the volume change of the injection liquid which the fuel injection valve 1 injected into the sealing chamber 14 is detected instead of the flow volume of the injection liquid which flows through a channel | path. Since the volume change of the injection fluid injected by the fuel injection valve 1 can be detected with high accuracy with a small number of injections, the flow rate measurement time can be shortened. The number of injections for measuring the injection flow rate may be one.

(Other embodiments)
In the above embodiment, the pressure sensor 20 side of the sealed chamber 14 is filled with the jet liquid 16 and the fuel injection valve 1 side of the sealed chamber 14 is filled with the air 18, but the sealed chamber 14 may be entirely filled with the air 18. In this case, the diaphragm 24 of the pressure sensor 20 is in contact with air on both sides. As a result of the injection liquid being injected into the sealed chamber 14, the pressure sensor 20 changes the pressure change ΔP of the sealed chamber 14 filled with air as the difference between the actual injection amount of the fuel injection valve 1 and the set injection amount Q. And the injection flow rate per one time of the fuel injection valve 1 can be measured. However, when all of the sealed chamber 14 is filled with air, the pressure change due to air is small, and therefore the volume of the entire sealed chamber 14 is preferably as small as possible.
Alternatively, all of the sealed chamber 14 may be filled with the injection liquid, and the injection liquid may be injected from the fuel injection valve 1 into the injection liquid.

In the above embodiment, each time the fuel injection valve 1 injects once, the protruding amount of the piston 36 protruding into the variable volume chamber 34 is controlled so that the volume of the variable volume chamber 34 increases by the set injection amount. The timing for increasing the volume of the volume chamber 34 may be before or after the fuel injection valve 1 injects, or at the same time as the injection. Further, the volume of the variable volume chamber 34 may be increased by the product of the number of injections and the set injection amount before and after the fuel injection valve 1 injects a plurality of times instead of every time the fuel injection valve 1 injects once. Good.
Alternatively, the injection flow rate may be measured by detecting the total amount of injection liquid injected by the fuel injection valve 1 as the pressure change ΔP without using the microsyringe 30.

In addition, the volume change of the injection liquid injected by the fuel injection valve 1 is detected as the pressure change ΔP by the pressure sensor 20, but the position sensor detects the volume change of the injection liquid injected by the fuel injection valve 1 as the displacement amount of the detection unit. May be used as detection means.
In the above embodiment, the flow rate of the fuel injection valve 1 of the internal combustion engine is measured. However, the flow rate of the present invention is not limited to this, and particularly when the injection flow rate of the fluid injection valve that injects a small amount of liquid is measured with high accuracy. The measuring device or the flow rate measuring method is effective.

It is typical explanatory drawing which shows the flow volume measuring apparatus by a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel injection valve (fluid injection valve), 10 Flow measuring device, 12 Housing, 14 Sealing chamber, 20 Pressure sensor (detection means), 30 Micro syringe (volume variable device), 34 Variable volume chamber, 36 Piston (movable member) , 40 On-off valve, 50 ECU (electronic control unit)

Claims (12)

In the flow rate measuring device that measures the jet flow rate of the liquid jetted by the fluid jet valve,
A housing having a sealed chamber, wherein the fluid ejection valve ejects liquid into the sealed chamber;
Detecting means connected to the sealed chamber for detecting a volume change of the liquid ejected from the fluid ejection valve to the sealed chamber;
A flow rate measuring device comprising:   The flow rate measuring device according to claim 1, wherein the sealed chamber is filled with gas in a state before measurement.   The flow rate measuring device according to claim 1, wherein the sealed chamber is filled with a liquid in a state before measurement.   2. The flow rate according to claim 1, wherein in a state before measurement, a side of the sealed chamber connected to the detection means is filled with a liquid, and the fluid injection valve side of the sealed chamber is filled with a gas. Measuring device.   An opening / closing valve for intermittently communicating between the atmosphere side and the sealed chamber, wherein the position of the boundary surface between the liquid and the gas in the sealed chamber is set to an initial position by opening the open / close valve; The flow rate measuring device according to claim 4.   6. The variable volume device further comprising: a variable volume chamber communicating with the sealed chamber; and a movable member that increases and decreases a volume of the variable volume chamber by moving. The flow rate measuring device described. In the flow rate measurement method for measuring the injection flow rate of the liquid injected by the fluid injection valve,
A flow rate measuring method comprising: injecting a liquid from the fluid injection valve into a sealed chamber, and measuring an injection flow rate of the fluid injection valve based on a value obtained by detecting a volume change of the liquid injected into the sealed chamber.   The flow rate measuring method according to claim 7, wherein the sealed chamber is filled with a gas before measurement.   The flow rate measuring method according to claim 7, wherein the sealed chamber is filled with a liquid before the measurement.   The flow rate measuring method according to claim 7, wherein the fluid injection valve side of the sealed chamber is filled with a gas before the measurement, and the other part of the sealed chamber is filled with a liquid.   The flow rate measuring method according to claim 10, wherein a boundary surface position between the liquid and the gas in the sealed chamber is set to an initial position before the measurement. When the fluid injection valve is opened for a predetermined time and is injected as a set injection amount, and the fluid injection valve injects a plurality of times, the volume of the sealed chamber or the space communicating with the sealed chamber is The flow rate measuring method according to claim 7, wherein the flow rate is increased by a product of the set injection amount and the number of injections.

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