JP2014013198A - Flow rate inspection apparatus and flow rate inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow rate inspection method that is capable of decreasing inspection time.SOLUTION: In a flow rate inspection method 100 of inspecting a flow rate of EGR gas that can flow through a gas passage 12 of an EGR control valve 10, after a valve 20 is set in a predetermined opening degree (θ), an opening area of the gas passage 12 is detected from an image of the valve 20 taken by a camera 2. Then a flow rate Q of the EGR gas that can flow through the gas passage 12 is calculated based on the detected opening area S(θ) of the gas passage 12, a flow rate coefficient η(θ) corresponding to the valve opening degree θ, as well as a constant α calculated from a pressure difference ΔP between upstream and downstream of the valve and an air density ρ. According to the flow rate inspection method 100, the flow rate Q can be calculated without flowing gas through the gas passage 12 of the EGR control valve 10 and applying an upstream and downstream pressure difference to the valve 20 of the EGR control valve 10.

Description

  The present invention relates to a flow rate inspection device and a flow rate inspection method for a fluid control valve.

Conventionally, an EGR control valve that controls the flow rate of EGR gas flowing through an exhaust gas recirculation passage provided in an engine is known. In the inspection of the flow characteristics performed when the EGR control valve is produced, a predetermined pressure of fluid is passed through the flow path of the EGR control valve, and after the valve opening is set, wait for the differential pressure across the valve to stabilize. The flow rate of the fluid flowing through the flow path is inspected. Note that the differential pressure across the valve is the differential pressure between the fluid pressure in the flow path upstream of the valve and the fluid pressure in the flow path downstream of the valve.
On the other hand, the valve opening calculation method described in Patent Document 1 detects the flow rate of the intake air flowing through the intake passage with an air flow meter when the engine is operating. Then, based on the difference between the detected flow rate value and the target flow rate value, a change in the opening area of the intake passage due to dirt and clogging of the throttle valve is calculated to correct the opening of the throttle valve.

JP 2006-299984 A

  By the way, in the EGR control valve used in the gasoline engine, the flow rate characteristic of the EGR gas with respect to the valve opening greatly affects the engine output and the like. For example, if the leakage flow rate of EGR gas is large when the valve is in the fully closed state, there is a possibility that the engine will start poorly or become rough idle. Further, when the flow rate characteristic of the EGR gas is deviated with respect to the predetermined opening of the valve, there is a concern that the output of the engine is reduced. Therefore, EGR control valves used in gasoline engines require flow rate inspections at multiple valve openings because there are flow specification requirements at multiple valve openings in addition to the valve fully closed and fully open positions from vehicle manufacturers. There is.

However, according to the conventional method for inspecting the flow characteristic of the EGR control valve, if the flow rate is inspected at a plurality of valve openings, the differential pressure difference between the front and rear of the valve is set after setting the valve opening at each valve opening. A waiting time is required for the to stabilize. Therefore, in the production of the EGR control valve, there is a concern that the time man-hour required for the inspection process increases.
Even in the method of Patent Document 1, the flow rate of the fluid flowing through the flow path is not stable until the differential pressure across the valve is stabilized after the throttle valve is set to the target opening, so We are anxious about detection taking time.

  The present invention has been made in view of the above problems, and an object thereof is to provide a flow rate inspection method and a flow rate inspection apparatus capable of shortening the inspection time.

The present invention relates to a flow rate inspection method for inspecting a flow rate of a fluid that can flow through a flow path of a fluid control valve, an opening area of the flow path detected from an image of the valve, a flow coefficient corresponding to the valve opening, and a predetermined amount The flow rate of the fluid that can flow through the flow path is calculated based on the constant.
As a result, the flow area of the flow path detected by image processing of the valve image without flowing a fluid through the flow path of the fluid control valve and without applying a differential pressure across the valve of the fluid control valve can be obtained. Based on this, it becomes possible to calculate the flow rate of the fluid that can flow through the flow path. Since no fluid flows in the flow path of the fluid control valve, there is no waiting time until the differential pressure across the valve stabilizes after the valve is set to a predetermined opening, and the inspection time is shortened. Therefore, since it is possible to perform a highly accurate flow rate inspection in a short time with a plurality of valve openings, the production efficiency of the fluid control valve can be increased.

The present invention can also be understood as an invention of a flow rate inspection apparatus.
The flow rate inspection device can circulate the flow path based on the opening area of the flow path detected from the image of the flow path of the fluid control valve by the valve photographing means, the flow coefficient corresponding to the valve opening, and a predetermined constant. Calculate the fluid flow rate.

It is a block diagram of the flow volume inspection apparatus by one Embodiment of this invention. It is an arrow view of the II direction of FIG. It is an arrow view of the III direction of FIG. FIG. 4 is an arrow view in a state where a cover is removed in the IV direction of FIG. 1. It is a schematic diagram of the image image | photographed with the camera of the flow volume inspection apparatus of one Embodiment. It is a graph which shows the relationship between a sensor output and a flow coefficient. It is a graph which shows the relationship between a sensor output and a flow volume factor. 3 is a flowchart of a flow rate inspection method according to an embodiment. It is a graph which shows the relationship between the valve opening degree and flow volume in the conventional flow inspection method.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
(One embodiment)
One embodiment of the present invention is shown in FIGS. The flow rate inspection apparatus 1 of this embodiment is an apparatus that inspects the flow rate characteristics of an EGR control valve 10 as a fluid control valve. The EGR control valve 10 is provided in an exhaust gas recirculation passage that communicates an exhaust passage and an intake passage of an engine, and controls the flow rate of EGR gas flowing therethrough.

(Configuration of EGR control valve)
First, the configuration of the EGR control valve 10 will be described with reference to FIGS.
The EGR control valve 10 includes a housing 11, a valve 20, a rotation angle sensor 30, a motor 40, and the like.
The housing 11 has a gas flow path 12 through which EGR gas can flow. The gas flow path 12 of the present embodiment corresponds to a “flow path” recited in the claims. The gas flow path 12 forms an introduction port 13 located on the upstream side of the valve 20 and a lead-out port 15 located on the downstream side of the valve 20. The introduction port 13 can be connected to a bypass pipe 14 connected to the exhaust passage of the engine. The lead-out port 15 can be connected to a merging pipe 16 connected to the intake passage of the engine.

A valve 20 is provided in the gas flow path 12 of the housing 11. A seal ring 21 is fitted in a groove provided on the outer periphery of the valve 20. When the valve 20 is closed, the seal ring 21 comes into airtight contact with the inner wall of the gas flow path 12.
A shaft 22 is connected to the valve 20. As the shaft 22 rotates around the axis, the valve opening is adjusted, and the valve 20 changes the opening area of the gas flow path 12. Thereby, the flow rate of the EGR gas flowing through the gas flow path 12 is controlled.

  The opening degree of the valve 20 is detected by the rotation angle sensor 30. The rotation angle sensor 30 includes two magnets 31 and 32 provided on the valve gear 23 that rotates together with the shaft 22, and a magnetic detection element such as a Hall IC 33 fixed to the housing cover 19. The Hall IC 33 detects the direction of the magnetic field of the two magnets 31 and 32 in a non-contact manner. When the EGR control valve 10 is mounted on the vehicle, a voltage signal output from the Hall IC 33 is transmitted from the connector 17 to an ECU (electronic control unit) of the vehicle (not shown).

  A motor 40 is provided inside the motor case 18 of the housing 11. The motor 40 is a DC motor, for example, and is rotationally driven by energization from the connector 17. A first gear 44 of the intermediate gear 43 meshes with a pinion gear 42 provided on the output shaft 41 of the motor 40. In the intermediate gear 43, a second gear 45 having a smaller outer diameter than the first gear 44 is engaged with the valve gear 23. The valve gear 23 rotates with the shaft 22 to which the valve 20 is connected.

  When the motor 40 is energized from the connector 17, the torque of the motor 40 is transmitted to the shaft 22 via the pinion gear 42, the intermediate gear 43, and the valve gear 23. Therefore, the valve 20 resists the urging force of the return spring 46 and rotates in the valve opening direction with the shaft 22 as the rotation axis. On the other hand, when energization of the motor 40 is stopped, the valve 20 rotates in the valve closing direction by the urging force of the return spring 46.

(Configuration of flow rate inspection device)
Next, the flow rate inspection apparatus 1 that inspects the flow rate characteristics of the EGR control valve 10 described above will be described.
As shown in FIG. 1, the flow rate inspection apparatus 1 includes a camera 2, a computer 3, a monitor 4, and the like.
The camera 2 of this embodiment corresponds to “bulb photographing means” described in the claims.
Further, the computer 3 of the present embodiment functions as “valve opening setting means”, “opening area detection means”, “flow rate calculation means”, and “determination means” described in the claims.

  In the inspection of the flow rate characteristic of the EGR control valve 10, the valve 20 is opened to a predetermined opening according to a command from the computer 3. At this time, the computer 3 functions as a valve opening setting means, and instructs the motor 40 to energize, for example, by PID control based on the output signal transmitted from the rotation angle sensor 30, thereby opening the valve 20 to a predetermined opening. Set to degrees.

The camera 2 is provided on the central axis of the introduction port 13 of the EGR control valve 10 and photographs the valve 20 from the introduction port 13. Image data taken by the camera 2 is transmitted to the computer 3.
The computer 3 functions as an opening area detection unit, performs image processing on the image data transmitted from the camera 2, and detects the opening area of the gas flow path 12. FIG. 5 schematically shows image data transmitted from the camera 2. In FIG. 5, the valve 20 is opened at a predetermined opening degree instructed by the computer 3. The opening area of the gas flow path 12 at this time is the sum of the areas A and B indicated by the one-dot chain line hatch.

ここで、Ｑは流量（ｍ³／ｓ）、
η（θ）はバルブ開度θにおける流量係数、
Ｓ（θ）はバルブ開度θにおける流路の開口面積（ｍ²）、
ΔＰはバルブの前後差圧（ｋｇ／ｍ³）、
ｔは温度（℃）、
ｐは大気圧（Ｐａ）、
ρ（ｔ，ｐ）は温度ｔ及び気圧ｐによって定まる空気密度（ｋｇ／ｍ³）である。 Further, the computer 3 functions as a flow rate calculation means, and calculates the flow rate of EGR gas that can flow through the gas flow path 12 at a predetermined valve opening degree using the following formula 1.

Where Q is the flow rate (m ³ / s),
η (θ) is the flow coefficient at the valve opening θ,
S (θ) is the opening area (m ² ) of the flow path at the valve opening θ,
ΔP is the differential pressure across the valve (kg / m ³ ),
t is temperature (° C),
p is atmospheric pressure (Pa),
ρ (t, p) is an air density (kg / m ³ ) determined by the temperature t and the atmospheric pressure p.

この定数αは、コンピュータ３に予め入力されている。 The front-rear differential pressure ΔP, the temperature t, the atmospheric pressure, and the air density ρ of the valve can be set according to the inspection condition and inspection environment of the flow rate characteristic of the EGR control valve 10. Therefore, when the constant calculated from these set numerical values is α, the constant α is expressed by the following Equation 2.

This constant α is input to the computer 3 in advance.

The flow coefficient η (θ) is also input in advance to the computer 3 corresponding to the opening θ of the valves 20 at a plurality of locations. The flow coefficient η (θ) is a numerical value calculated using Equation 1 from an actual flow rate actually measured using a plurality of EGR control valve 10 samples.
Specifically, the flow coefficient η (θ) is calculated by the following method.
First, by using a plurality of samples of the EGR control valve 10, the opening degree θ of the valve 20 is set to be the sensor outputs V 1 to V 4 of the rotation angle sensor 30, and the gas flow path 12 of the EGR control valve 10 is set. A gas having a predetermined air density ρ is flowed. Then, after the pressure difference ΔP across the valve 20 is stabilized at, for example, 6.7 kPa, the flow rates Q1 to Q4 are measured using a flow bench (flow rate measuring device) not shown.
Next, it is calculated from the flow rates Q1 to Q4 measured by the flow bench, the opening area S (θ) corresponding to the valve opening θ, the air density ρ of the gas used for the actual measurement, and the differential pressure ΔP across the valve 20. The flow coefficient η (θ) is calculated using the constant α and the above-described equation 1. Note that the opening area S (θ) of the flow path is the opening area obtained by analyzing the image data photographed by the camera 2.

An example of the relationship between the sensor outputs V1 to V4 and the flow coefficients η1 to η4 calculated in this manner is shown in FIG. In this way, the flow coefficient η (θ) corresponding to the openings θ (that is, sensor outputs V1 to V4) of the valves 20 at a plurality of locations can be input to the computer 3 in advance.
Further, for example, a function representing the relationship between the opening degree of the valve 20 (that is, sensor output) and the flow coefficient, which is set based on the graph of FIG.

The flow rate calculated by the computer 3 is displayed on the monitor 4. The computer 3 functions as a determination unit, determines whether the flow rate is within the standard value range of the EGR control valve 10, and displays the result on the monitor 4.
As shown in FIG. 7, the standard value of the EGR control valve 10 is input to the computer 3 in advance. The broken line C and the broken line D in FIG. 7 are set with a predetermined allowable value with respect to the reference value E.
If the flow rate with respect to the predetermined valve opening is between the broken line C and the broken line D in FIG. 7, the computer 3 determines that the EGR control valve 10 to be inspected is within the standard value range. On the other hand, if the flow rate for the predetermined valve opening is not between the broken line C and the broken line D in FIG. 7, the computer 3 determines that the EGR control valve 10 to be inspected is not within the standard value range. To do.

(Flow rate inspection method)
Next, the flow rate inspection method 100 performed by the flow rate inspection apparatus 1 will be described with reference to the flowchart of FIG.
First, at the flow rate inspection start 101, the EGR control valve 10 to be inspected is set in the flow rate inspection apparatus 1. Then, the motor 40 of the EGR control valve 10 is energized, and the valve 20 is put on standby at the default position. Note that the default position of the EGR control valve 10 of the present embodiment is the fully closed position.

  In the valve opening setting step 102, the computer 3 opens the valve 20 to a predetermined opening θ based on an output signal transmitted from the rotation angle sensor 30, for example, by PID control. When the flow rate inspection is performed at the valve fully closed position, the valve opening is maintained at the default position.

In the bulb photographing process 103, the camera 20 photographs the bulb 20 from the introduction port 13. The camera 2 transmits the image data to the computer 3.
In the opening area detection step 104, the computer 3 performs image processing on the image data transmitted from the camera 2 and detects the opening area S (θ) of the gas flow path 12.

In the flow coefficient and constant reading step 105, the computer 3 reads the flow coefficient η (θ) corresponding to the opening degree of the valve 20 and the constant α from the memory of the computer 3.
In the case where a function representing the relationship between the valve opening degree θ of the valve 20 and the flow coefficient η is stored in the memory, the computer 3 reads the function and reads the flow coefficient η ( θ) is calculated.

In the flow rate calculation step 106, the computer 3 calculates the flow rate of the EGR gas that can flow through the gas flow path 12 at the predetermined valve opening θ using the above-described equation 1.
In the determination step 107, the computer 3 compares the calculated flow rate Q with the standard value of the EGR control valve 10.
Based on the graph shown in FIG. 7, when the flow rate Q with respect to a predetermined valve opening is within the range of the standard value of the EGR control valve 10 (between the broken line C and the broken line D), the computer 3 determines that the monitor 4 is OK. Display verdict. On the other hand, the computer 3 displays an NG determination on the monitor 4 when the flow rate for the predetermined valve opening is not within the standard value range (between the broken line C and the broken line D).

(Conventional flow rate inspection method)
Here, a conventional flow rate inspection method will be described.
In the conventional flow rate inspection method, a fluid (air) having a predetermined pressure is actually flowed through the flow path of the EGR control valve to be inspected, and the flow rate of the fluid is measured.

More specifically, in a first step in the conventional flow rate inspection method, a predetermined differential pressure across the valve is applied to the flow path of the EGR control valve in the fully closed state of the valve.
Next, in the second step, the computer opens the set valve to a predetermined opening degree and flows the fluid based on the output signal transmitted from the rotation angle sensor by PID control.

The relationship between the valve opening and the flow rate at this time is shown in FIG. In FIG. 9, the valve opening (sensor output) is indicated by a solid line F, and the flow rate flowing through the flow path is indicated by a solid line G.
In the second step described above, when an instruction to change the valve opening is received from the computer, the valve opening changes from V1 to V2 between times t1 and t2.
However, between time t1 and time t3, the differential pressure across the valve is not stable, and the flow rate of the gas flowing through the flow path is not stable. The differential pressure across the valve stabilizes after time t3.
In the third step, after time t3, a flow bench or the like is used to measure the flow rate of the gas flowing through the flow path. The flow rate measured by the flow bench is input to the computer.

In the fourth step, the computer compares the calculated flow rate with the standard value of the EGR control valve. The computer makes an OK determination when the flow rate for a predetermined valve opening is within the range of the standard value of the EGR control valve. On the other hand, when the EGR control valve is not within the standard value range, the computer makes an NG determination regarding the flow rate with respect to the predetermined valve opening.
As described above, in the conventional flow rate inspection method, the time from the time t1 when the instruction to change the valve opening degree is given from the computer to the time t3 when the flow bench starts to detect the flow becomes longer. Therefore, in the production of the EGR control valve, there is a concern that the time man-hour required for the inspection process increases.

(Operational effect of this embodiment)
On the other hand, in this embodiment, there exist the following effects.
(1) In the present embodiment, the flow rate inspection apparatus 1 uses the camera 2 to detect an opening area S (θ) of the flow path detected from an image of the gas flow path 12 of the EGR control valve 10 and the opening θ ( That is, the flow rate Q of EGR gas that can flow through the gas flow path 12 is calculated based on the flow coefficient η (θ) corresponding to the sensor output V) and the predetermined constant α. As a result, the flow rate Q of the gas that can flow through the gas flow path 12 without flowing gas through the gas flow path 12 of the EGR control valve 10 and without applying the differential pressure ΔP to the valve 20 of the EGR control valve 10. Can be calculated.
Therefore, in the flow rate inspection method 100 of the present embodiment, the waiting time (time t1 to t3) until the differential pressure across the valve 20 is stabilized after the valve 20 is set to a predetermined opening as in the conventional flow rate inspection method. This eliminates the inspection time. Therefore, it is possible to perform a highly accurate flow rate inspection in a short time with a plurality of valve openings, and the production efficiency of the EGR control valve 10 can be increased.

(2) In the present embodiment, the flow coefficient η (θ) corresponding to the openings of the valves 20 at a plurality of locations is input to the computer 3 in advance. Thereby, the flow rate inspection apparatus 1 can perform a flow rate inspection at a plurality of valve openings in a short time.
(3) In the present embodiment, the measured flow rate at a plurality of valve opening positions measured using a plurality of EGR control valve 10 samples, the opening area S (θ) of the flow path photographed by the camera, the valve 20 The flow coefficient η (θ) is calculated from the constant α calculated from the differential pressure ΔP, the temperature t, the atmospheric pressure, and the air density ρ. Thereby, the flow inspection apparatus 1 can perform a highly accurate flow inspection in a short time using an accurate flow coefficient.

  (4) In the present embodiment, a function representing the relationship between the valve opening degree and the flow coefficient η (θ) is input in advance to the computer 3, and the flow coefficient η (θ) is calculated using the function. Good. Thereby, the flow rate inspection apparatus 1 can perform a flow rate inspection in a short time with an arbitrary valve opening.

  (5) In the present embodiment, the flow rate Q of the gas that can flow through the gas flow path 12 is calculated from the above equation 1. Thereby, the flow rate inspection apparatus 1 can perform a highly accurate flow rate inspection in a short time based on the opening area S (θ) of the gas flow path 12 detected by image processing.

(Other embodiments)
In the above-described embodiment, the flow rate inspection apparatus 1 that inspects the flow rate characteristic of the EGR control valve 10 has been described. On the other hand, in other embodiments, the flow rate inspection device can be a device that inspects the flow rate characteristics of various fluid control valves that control the flow rate of the fluid. The flow rate inspection method can be a method for inspecting the flow rate characteristics of various fluid control valves that control the flow rate of the fluid.
In the embodiment described above, the camera 2 is provided on the central axis of the introduction port 13 of the EGR control valve 10, and the valve 20 is photographed from the introduction port 13 by the camera 2. On the other hand, in other embodiments, a camera may be provided on the central axis of the derivation port of the EGR control valve, and the valve may be photographed from the derivation port.
The present invention is not limited to the above embodiment, and can be implemented in various forms without departing from the spirit of the invention.

2 ... Camera (bulb photography means)
3... Computer 10... EGR control valve (fluid control valve)
12 ... Gas flow path (flow path)
20 ... Valve 102 ... Valve opening setting step 103 ... Valve photographing step 104 ... Opening area detection step 106 ... Flow rate calculation step

Claims (9)

A flow rate inspection method (100) for inspecting a flow rate of a fluid that can flow through a flow path (12) of a fluid control valve (10) using a computer (3),
A valve opening setting step (102) for energizing the fluid control valve and setting a valve (20) provided in the flow path of the fluid control valve to a predetermined opening;
A bulb photographing step (103) for photographing the valve through the flow path of the fluid control valve using a bulb photographing means (2);
An opening area detecting step (104) for detecting an opening area of the flow path from the image of the valve and the flow path taken in the bulb photographing process;
Based on the opening area detected in the opening area detection step, a flow coefficient corresponding to the valve opening, and a constant calculated from the differential pressure and the air density before and after the valve, the flow rate of the fluid that can flow through the flow path And a flow rate calculation step (106) for calculating the flow rate. In the computer, flow coefficients corresponding to the valve openings at a plurality of locations are stored in advance,
The flow rate inspection method according to claim 1, wherein in the flow rate calculation step, a flow rate is calculated by reading a flow rate coefficient input in advance to the computer.   The flow coefficient was calculated from the measured flow rate at a plurality of valve openings measured using a plurality of fluid control valve samples, and the constant was calculated from the differential pressure across the valve and the air density. The flow rate inspection method according to claim 2, wherein the flow rate inspection method is one.   The computer stores in advance a function representing the relationship between the valve opening and the flow coefficient, and the flow rate calculation step calculates the flow coefficient using the function input in advance to the computer. The flow rate inspection method according to claim 1.   The function is a constant calculated from a measured flow rate at a plurality of valve openings, a valve opening area, a differential pressure across the valve, and an air density measured using a plurality of fluid control valve samples. The flow rate inspection method according to claim 4, wherein the flow rate inspection method is determined based on the above. The flow rate inspection method according to claim 1, wherein the flow rate of the fluid that can flow through the flow path of the fluid control valve is calculated from the following Equation 1.

Where Q is the flow rate (m ³ / s),
η (θ) is the flow coefficient at the valve opening θ,
S (θ) is the opening area (m ² ) of the flow path at the valve opening θ,
ΔP is the differential pressure across the valve (kg / m ³ ).
t is temperature (° C),
p is atmospheric pressure (Pa),
ρ (t, p) is an air density (kg / m ³ ) determined by the temperature t and the atmospheric pressure p.
If the manufacturing process is air-conditioned, the temperature is constant, that is, the route is constant (constant). However, in an environment where the temperature changes greatly every day, a temperature sensor is set in the flow inspection facility to correct the density. (In this case, the constant α changes daily).   In the valve opening setting step, a predetermined opening degree of the valve is controlled by driving and controlling a motor (40) that operates the valve based on an output signal of a rotation angle sensor (30) that outputs a signal based on the valve opening. The flow rate inspection method according to claim 1, wherein the flow rate inspection method is set to degrees.   8. The method according to claim 1, further comprising a determination step (107) for determining whether or not the flow rate calculated in the flow rate calculation step is within a range of a standard value of the fluid control valve. The flow rate inspection method described in 1. A valve opening setting means (3) for energizing the fluid control valve and setting a valve provided in the flow path of the fluid control valve to a predetermined opening;
Valve imaging means (2) for imaging the valve through the flow path of the fluid control valve;
An opening area detecting means (3) for detecting an opening area of the flow path from an image of the bulb photographed by the bulb photographing means;
Based on the opening area detected by the opening area detecting means, the flow coefficient corresponding to the valve opening, and a constant calculated from the differential pressure across the valve and the air density, the flow rate of the fluid that can flow through the flow path A flow rate inspection device (1) comprising: a flow rate calculation means (3) for calculating the flow rate.

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