JP2009085842A - Bag for constant-volume dilution/sampling apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bag for a constant-volume dilution sampling apparatus which can shorten the length of a connecting tube that joins a CVS device with a bag. <P>SOLUTION: A bag for a constant-volume dilution sampling device includes: a gas inlet/outlet section, having an internal flow channel system through which a gas can flow in and out; a pipe, communicating with the internal flow channel system of the gas inlet/outlet section, which has a peripheral wall provided with a plurality of gas ejection holes through which the gas can be ejected; and the bag body which has an internal space keeping the pipe housed and which can be filled with the gas. The gas inlet/outlet section is placed at the periphery of the bag body, at the time when the internal space has not been filled with the gas. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bag for a constant volume dilution sampling apparatus capable of shortening the length of a connecting pipe connecting a CVS apparatus and a bag.

  Conventionally, the method of measuring the components of engine exhaust gas such as automobiles can be broadly divided into “dilution sampling method” in which exhaust gas is diluted with air when sampling exhaust gas and “direct sampling method” in which dilution is not performed. These methods are properly used according to the purpose and conditions of the exhaust gas test.

  In the direct sampling method (direct method), the concentration of the collected engine exhaust gas is measured as it is without dilution, whereas in the dilution sampling method (dilution method), the collected engine exhaust gas is diluted several times in the atmosphere. Measure concentration. According to the dilution sampling method, the moisture concentration in the sample can be reduced, and condensation in the pipe is unlikely to occur, so that it is possible to suppress a measurement error due to a change in gas concentration due to water condensation and a dissolution loss of water-soluble components.

Widely adopted as a dilution method is constant volume sampling (Constant
In this method, the total amount of engine exhaust gas is diluted with the atmosphere to a constant known flow rate. Recently, a system called a bag minidiluter (BMD) method has been devised that collects a part of exhaust gas and dilutes it at a fixed ratio. The CVS method is the most common dilution sampling method at present. As shown in FIG. 12, the concept of using the venturi method is as follows. In this method, the total amount of exhaust gas and the atmosphere for dilution are introduced into the apparatus, and these are used. The total flow rate is controlled so that it is always constant. Part of the diluted exhaust gas is collected in a bag at a constant flow rate, and the concentration in the bag is analyzed after the test is completed. The exhaust gas mass can be obtained from this concentration, the flow rate of the diluted exhaust gas, the sampling time, and the gas density of the target component.

  As such a bag, for example, as shown in FIG. 13, a bag body 3 formed by bonding four sides of two resin sheets, and a figure 8 in a planar view inside the bag body. The pipes 2a and 2b arranged at the center, the gas inlet / outlet part 1 connecting the external gas flow path and the pipe internal flow path, and the bag to the CVS device. The pipe 2 has a small diameter (for example, gas can be ejected from all the gas ejection holes even if the pressure is lost) at a uniform interval on the peripheral wall over the entire length of the pipe 2. A bag A in which a plurality of gas ejection holes having a diameter of a certain size is formed is used.

  Then, the gas inlet / outlet part 1 of the bag A is connected to a constant volume sampling channel through which diluted exhaust gas flows, and the diluted exhaust gas is introduced into the pipes 2a and 2b, whereby the diluted exhaust gas is filled in the bag body 3. It is comprised so that.

  The diluted exhaust gas in the bag body 3 can be introduced into the gas analyzer by sucking with a suction pump provided downstream of the bag A, and the diluted exhaust gas can be measured. If the same gas is introduced in the same manner, the next measurement can be performed subsequently (see, for example, Patent Document 1).

  Since the exhaust gas is diluted in the CVS method, it is possible to suppress compositional changes due to water condensation and chemical interaction of active components. In addition, in the method of measuring the gas averaged in the bag after running Therefore, the influence of the response delay of the analyzer can be ignored. Since the CVS method has many advantages as described above, it is currently used as a standard in exhaust gas certification tests for new vehicles and exhaust gas tests for in-use vehicles in the United States, Europe and Japan.

  As shown in FIG. 14 as an example of the gas flow, the CVS apparatus is roughly divided into an exhaust gas and dilution air mixing unit, a mixed gas flow rate control unit, and a bag sampling unit. The reason why there are a plurality of bags is that the bags need to be switched at the test mode.

The dilution flow rate in the CVS apparatus is set according to the displacement of the test engine, the test mode, the atmospheric conditions, and the like. Even when the exhaust gas flow rate becomes maximum during the test, it is a necessary condition that the moisture concentration in the exhaust gas after dilution is not more than the dew point, and the operation at about 5 to 10 times the average exhaust gas flow rate is common.
Japanese Patent Laid-Open No. 2005-055333

  The CVS method has a sample averaging effect by collecting bags, and is an excellent method that can measure exhaust gas with high accuracy. However, as the exhaust gas component to be measured is reduced in concentration, there are several error factors. In particular, hydrocarbons (hereinafter referred to as HC) in engine exhaust gas are likely to be adsorbed and desorbed from the components of the measurement system, which causes a measurement error.

  When a conventional bag as shown in FIG. 13 is used, since the gas inlet / outlet portion is located at the center of the bag, a certain length is required for the connecting pipe connecting the CVS device and the gas inlet / outlet portion of the bag. However, recently, the accuracy of sampling has been required as the exhaust gas concentration decreases, and the exhaust gas components are adsorbed into the connection pipe, the exhaust gas components once adsorbed, or left in the connection pipe during the previous test. The effects of exhaust gas can no longer be ignored. Moreover, the water concentration of the diluted exhaust gas of CVS is averaged in the bag and does not become as high as that in the piping up to that point. Therefore, it is conceivable to reduce the dilution rate to the level just below the dew point, keep the dilution air volume to the minimum necessary, and sufficiently heat the piping to the bag inlet to ensure measurement accuracy. Providing a heating device in the connecting pipe increases the size of the entire device, complicates the configuration, and requires complex control to obtain a desired effect.

  Therefore, the present invention is intended to provide a bag for a constant volume dilution sampling apparatus capable of shortening the length of the connecting pipe connecting the CVS apparatus and the bag.

  That is, the constant volume dilution sampling device bag (hereinafter also referred to as a CVS device bag) according to the present invention includes a gas inlet / outlet portion having an internal flow path system capable of inflowing and inflowing gas, and an internal flow of the gas inlet / outlet portion. A pipe that communicates with the road system and has a plurality of gas ejection holes formed on its peripheral wall through which the gas can be ejected; and an internal space in which the pipe is accommodated, and the internal space is filled with gas A bag main body, and the gas inlet / outlet portion is installed at a peripheral edge portion of the bag main body when the gas is not filled in the internal space.

  The CVS device bag according to the present invention is normally used for collecting exhaust gas diluted with dilution air and dilution air used as a control by being installed in the CVS device. Further, in the present invention, “at the time when the internal space is not filled with gas” means when the internal space of the bag body is not filled with gas and the bag body is deflated and flat. Furthermore, in the present invention, the “peripheral portion” refers to a portion closer to the edge than the edge or the center of gravity in the bag body when the gas is not filled in the internal space.

  If it is such, since the said gas in / out part is installed in the peripheral part of the said bag main body, the said gas in / out part can be brought close to the exhaust gas sampling port of a CVS apparatus, and, thereby, a CVS apparatus and CVS Since the length of the connecting pipe connecting the device bag can be shortened, it is possible to minimize the adsorption and desorption of exhaust gas components into the connecting pipe, and the exhaust gas temperature in the connecting pipe can be reduced. It is possible to reduce the decrease, and to suppress condensation due to dew point reduction, gas concentration change due to water condensation, and measurement errors due to dissolution loss of water-soluble components. In addition, since the dead volume inside the connecting pipe is reduced, the dead time until the exhaust gas collected from the exhaust gas sampling port of the CVS device is accumulated in the bag is shortened, and the measurement time difference can be reduced. Moreover, the amount of exhaust gas remaining in the connecting pipe after the test can be reduced. Therefore, according to the present invention, more accurate sampling is possible.

  The CVS device bag is usually arranged suspended from the CVS device. In order to be able to hang in this way, the normal CVS device bag has a hook, but the conventional product has only one hook. Not. In contrast, the CVS device bag according to the present invention preferably includes two hooks.

  If two hooks are provided in this way, for example, if the two hooks are provided at two symmetrical positions of the bag body, the connecting pipe is shortened in accordance with the position of the exhaust gas sampling port of the CVS device. The CVS device bag can be suspended upside down. Moreover, if it is such, it will also become possible to connect and arrange the plurality of CVS device bags according to the present invention vertically. For this reason, the degree of freedom of the layout of the bag for the CVS device is increased, and the pair of the dilution air bag and the exhaust gas bag has conventionally been difficult to understand, but according to the present invention, the pair can be suspended up and down. This makes it easier to identify pairs.

  Furthermore, it is preferable that a plurality of the gas inlet / outlet portions are provided. If a plurality of the gas inlet / outlet portions are provided, the degree of freedom of the layout of the CVS device bag for shortening the connecting pipe can be further increased.

  As described above, according to the present invention, the length of the connecting pipe that connects the CVS device and the gas inlet / outlet portion of the bag for the CVS device can be shortened. Reduces the measurement time difference, reduces the effect of residual exhaust gas, reduces the exhaust gas temperature in the connection pipe, reduces condensation due to dew point reduction, changes in gas concentration due to water condensation, and water-soluble components Measurement errors due to melting loss of the can be suppressed. Therefore, according to the present invention, highly accurate sampling is possible.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  The CVS device bag A according to this embodiment is for collecting exhaust gas diluted with dilution air and dilution air as a control installed in the CVS device, and as shown in FIGS. A gas inlet / outlet part 1 having an internal flow path system 10 through which gas can flow in and out, and a plurality of gas ejection holes communicating with the internal flow path system 10 of the gas inlet / outlet part 1 and capable of jetting the gas to the peripheral wall thereof 21 includes a pipe 2 in which a pipe 21 is formed, a bag body 3 having an internal space 30 in which the pipe 2 is accommodated, and a hook 6 that is suspended from a CVS apparatus and installed.

Hereinafter, each part will be described.
The gas inlet / outlet portion 1 is provided at two corners at the upper left and upper right in FIG. 1 and is substantially cylindrical in shape as shown in FIG. 3 and connected to the pipe 2 from the top surface 1a. The internal flow path system 10 (not shown in FIG. 3) formed over the side peripheral surface 1b which is a surface to be provided is provided.

  Specifically, as shown in FIGS. 4 to 6, the internal flow path system 10 includes a gas inlet / outlet hole 11 having a bottomed cylindrical shape extending from the center of the top surface 1 a toward the bottom surface 1 c, and the gas inlet / outlet hole. 11 has a substantially circular cross-section 12 that communicates an opening 11b provided on the inner wall surface and an opening 1bx provided on the side peripheral surface 1b, and an opening 11c provided on the inner wall surface of the gas inlet / outlet port 11 and the side peripheral surface. And an exhaust passage 13 that communicates with the gas discharge port 4 provided at the top.

  The gas inlet / outlet port 11 is connected to the CVS device via a connecting pipe, and the gas inlet / outlet part 1 and the connecting pipe are formed by slightly projecting the opening 11a side of the gas inlet / outlet hole 11 from the top surface 1a. It can be easily connected with. In the present embodiment, the inner diameter of the gas inlet / outlet hole 11 is set larger than the inner diameter of the pipe 2.

  The diversion channel 12 communicates with the pipe 2 in the opening 1bx provided in the side peripheral surface 1b. In the present embodiment, the inner diameter of the branch channel 12 is set to be substantially the same as the inner diameter of the pipe 2.

  The exhaust flow path 13 includes an accommodating portion 131 that accommodates an operating body 51 of the check valve 5 and the like, which will be described later, in the middle of the flow path 13.

  The check valve 5 allows passage of the diluted exhaust gas G1 during forced exhaust, while preventing passage of the exhaust gas G1 during non-exhaust. Specifically, the check valve 5 can be moved back and forth between a closed position (P1) (see FIG. 7) for closing the exhaust passage 13 and an open position (P2) (see FIG. 8) for opening. Body 51 and an urging member 52 such as a spring that constantly urges the working body 51 in the direction from the open position (P2) to the closed position (P1). Exhaust force for exhausting the exhaust gas G1 after this overcomes the urging force of the urging member 52 and moves the operating body 51 from the closed position (P1) to the open position (P2), thereby allowing the exhaust gas G1 after dilution to pass. On the other hand, the operating body 51 stays at the open position (P2) to prevent the passage of gas during non-exhaust.

  The pipe 2 is accommodated in the internal space 30 of the bag body 3, and is formed of, for example, a fluororesin having substantially the same cross-sectional shape in the longitudinal direction.

  The pipe 2 has a plurality of gas ejection holes 21 at regular intervals on its peripheral wall over its entire length. The gas ejection holes 21 have such a diameter that gas can be ejected from all the gas ejection holes 21 even when pressure is lost. The closer to the gas inlet / outlet part 1, the smaller the diameter. The farther one is configured to have a larger diameter. Further, the gas ejection hole 21 is opened in a direction substantially opposite to the peripheral portion of the back body 3 in the peripheral wall of the pipe 2, whereby the gas ejection hole 21 is deflated when the gas is forcibly exhausted. 3 is prevented from being blocked.

  The bag body 3 is configured to be stretchable by bonding two sides of a sheet made of a flexible material such as a resin sheet (for example, having a capacity of 90 L, length 115 cm × width 75 cm). Then, by filling the gas, the bag body 3 is expanded in the thickness direction as indicated by an imaginary line in FIG.

  In exhaust gas analysis using the CVS method, line contamination due to HC can occur in most parts that come into contact with exhaust gas. Therefore, in the system for low concentration measurement, the part that comes into contact with exhaust gas is minimized and the materials used are considered sufficiently. Although it is necessary, if a vinyl chloride resin generally used as a material for the bag A for the CVS device is used, there arises a problem that HC springs out from the vinyl chloride resin.

  For this reason, as the bag main body 3 in this embodiment, polyvinyl fluoride (poly (vinyl fluoride), PVF), polyvinylidene fluoride (poly (vinylidene fluoride), PVDF), polytetrafluoroethylene (poly (tetrafluorethylene), PTFE). ), Tetrafluoroethylene-hexafluoropropylene copolymer (tetrafluoroethylene / hexafluoropropylene copolymer, FEP) and the like are preferably used.

  The hooks 6 are provided at two locations on the upper and lower sides of the bag body 3, and the CVS device bag A can be suspended and installed on the CVS device via the hooks 6.

  Therefore, according to the CVS device bag A according to the present embodiment configured as described above, since the gas inlet / outlet portion 1 is provided at the peripheral edge of the bag body 3, the gas inlet / outlet of the CVS device and the bag A for CVS device A is provided. Since the connecting pipe connecting the part 1 can be shortened, the adsorption of the exhaust gas component into the connection pipe and the desorption of the exhaust gas component once adsorbed can be reduced. In addition, as the dead volume inside the connecting pipe decreases, the dead time until the exhaust gas collected from the exhaust gas collection port of the CVS device accumulates in the bag can be shortened. Moreover, the amount of exhaust gas remaining in the connecting pipe after the test can be reduced. Therefore, according to the CVS device bag A according to the present embodiment, more accurate sampling is possible.

  Further, in the CVS device bag A according to the present embodiment, since the gas inlet / outlet portion 1 and the hook 6 are provided at two locations on the bag body 3, as shown in FIGS. 9 and 10, exhaust gas sampling of the CVS device is performed. The CVS device bag A can be suspended upside down according to the position of the mouth. Further, a plurality of CVS device bags A according to the present embodiment can be vertically connected. For this reason, the degree of freedom of layout of the CVS device bag A is increased, and the pair of the dilution air bag and the exhaust gas bag is conventionally difficult to understand, but according to the present invention, the pair is suspended vertically. This makes it easy to identify the pair.

  The present invention is not limited to the above embodiment.

  The shape of the bag body of the CVS device bag according to the present invention is not particularly limited. For example, the outer shape when the gas is filled may be a rotating body such as a columnar shape, a spherical shape or a lantern shape, or a polygonal column shape. .

  For example, if the shape of the bag body is cylindrical, it is possible to reduce the area where the inside of the bag is in contact with the exhaust gas, so that adsorption and desorption of exhaust gas components can be reduced, and further, after exhaust gas component measurement is completed The purge time can also be reduced.

  On the other hand, if the shape of the bag body is a regular prismatic shape such as a regular hexagonal column, the bags can be arranged densely even when gas accumulates in a plurality of bags, so that the space can be used effectively.

  Further, the size of the bag body is not limited to the size in the above embodiment, and can be appropriately determined according to the purpose of the test. Furthermore, the length of the pipe can be adjusted as appropriate according to the size of the bag body.

  For example, even if the test vehicle is a low-concentration exhaust vehicle, a relatively high concentration gas is often discharged immediately after the engine is started. In such a case, in addition to the normal measurement line, a low-concentration exhaust gas is used. Using a CVS device with a dedicated line, the phases other than the cold start in the test mode (schedule for starting the measurement from the start of the engine, no warm-up) are measured on the low concentration line, and the HC adsorption at the cold start is Take measures to prevent the impact. In such a case, the CVS device bag according to the present invention and the conventional CVS device bag are used together, the CVS device bag according to the present invention is used only for the low concentration line, and the normal measurement line is used. A conventional bag for a CVS device may be used. In this case, it is also possible to further provide a heating unit that heats the connecting pipe in the low concentration line, and to cope with higher accuracy measurement.

Although fluororesin has the characteristic that the amount of HC protruding is very small, the permeability of CO ₂ is large. Therefore, when measuring fuel consumption, the bag body material should be flexible other than fluororesin. It is preferable to use the material which has.

  The installation position of the gas inlet / outlet portion is not limited to the above embodiment, and may be any peripheral edge portion of the bag body when not filled with gas, and may be provided on the side surface of the bag body as shown in FIG. Further, the number of gas inlet / outlet portions is not limited to two, and may be one or three or more. In the case of three or more, if there is one hook 6, the degree of freedom in layout can be ensured.

  The structure of the gas inlet / outlet portion is not limited to the structure in the above embodiment as long as gas can flow in and out, and may be another structure.

  In addition, it is needless to say that some or all of the above-described embodiments and modified embodiments may be appropriately combined, and various modifications can be made without departing from the scope of the invention.

The front view of the bag for CVS apparatuses (at the time of gas unfilling) in one embodiment of the present invention. The side view of the bag for CVS apparatuses (at the time of gas unfilling) in the embodiment. The perspective view showing the connection aspect of the gas in / out part and pipe in the embodiment. The figure which expands and shows the principal part which is a connection part of the gas in / out part and pipe in the embodiment. D1-D1 sectional drawing in FIG. D2-D2 sectional drawing in FIG. The principal part expanded sectional view in the state where gas spouts from the pipe in the embodiment. The principal part expanded sectional view in the state by which gas is discharged | emitted from the gas discharge port in the same embodiment. The figure which shows typically an example which installed the bag for CVS apparatuses in the embodiment in the CVS apparatus. The figure which shows typically another example which installed the bag for CVS apparatuses in the embodiment in the CVS apparatus. The side view of the bag for CVS apparatuses (at the time of gas non-filling) in other embodiments. The figure which shows roughly an example of a CVS apparatus (venturi system). The front view of the bag for conventional CVS devices (at the time of gas non-filling). The channel diagram which shows the gas flow of a CVS apparatus.

Explanation of symbols

A ... CVS device bag 1 ... gas inlet / outlet portion 1b ... surface connecting the pipe 2 of the gas inlet / outlet portion 1 (side circumferential surface)
2 ... Pipe 3 ... Bag body 4 ... Gas outlet 5 ... Valve (check valve)
6 ... Hook 10 ... Internal flow path system 11 of gas inlet / outlet part 1 ... Gas inlet / outlet hole 12 ... Split channel 13 ... Exhaust channel 21 ... Gas outlet hole 30 ... Internal space 51 ... Actuator 52 ... Biasing member (P1) ... Closure position (P2) ... Open position

Claims (3)

A gas inlet / outlet part having an internal flow path system capable of inflowing / outflowing gas;
A pipe that communicates with the internal flow path system of the gas inlet / outlet portion and has a plurality of gas ejection holes formed on its peripheral wall through which the gas can be ejected;
A bag body having an internal space in which the pipe is accommodated, and capable of filling the internal space with a gas;
A bag for a constant volume dilution sampling apparatus, wherein the gas inlet / outlet portion is installed at a peripheral edge portion of the bag main body when the gas is not filled in the internal space.   The bag for a constant volume dilution sampling apparatus according to claim 1, comprising two hooks.   The bag for a constant volume dilution sampling apparatus according to claim 1 or 2, wherein a plurality of the gas inlet / outlet portions are provided.