JP2017223647A - Flow rate measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To resolve a state running short of an amount flow of measured air to a sub-channel 5 upon reverse flow in a thermal type flow rate measurement device 1, and to suppress measurement accuracy from falling.SOLUTION: In a flow rate measurement device 1, let a direction of a line connecting an upstream end of a seal part to a downstream end be defined as a reference direction α, and, when supposing an angle θ1 to be formed between a direction heading for an apex 23 of a bump 21 from the upstream end 24 and the reference direction α, and an angle θ2 to be formed between a direction heading for the apex 23 from the downstream end 25 and the reference direction α regarding the apex 23, upstream end 24 and downstream end 25, α, a relation of θ1<θ2<90° is established. Accordingly, upon a reverse flow, separation of a flow in the vicinity of the apex 23 of the bump 21 can be prevented. In the flow rate measurement device 1, upon the reverse flow, a state running short of an amount of flow of inhalation air to a sub-channel 5 is resolved to enable suppression of accuracy from falling.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a thermal flow rate measuring apparatus for measuring a flow rate of a gas to be measured as a measurement target.

  2. Description of the Related Art Conventionally, a structure including a housing and a flow sensor as described below is well known in a thermal flow measuring device. That is, according to this known structure, the housing has a sub-passage through which the gas to be measured flowing through the main passage is taken in, and the flow rate sensor is arranged in the sub-passage and flows through the sub-passage. A signal corresponding to the flow rate of the gas to be measured flowing through the main passage is generated by the heat transfer. Then, the flow measuring device returns the gas to be measured that has passed through the flow sensor from the outlet of the sub passage to the main passage.

  By the way, when such a flow rate measuring device is used to measure the flow rate of intake air sucked into the internal combustion engine, the flow rate measuring device includes not only the flow rate when the intake air flows in the forward direction but also the reverse flow. It is also required to measure the flow rate when flowing in the direction. That is, the flow rate of the intake air pulsates based on the operation of the internal combustion engine, and when the operating state of the internal combustion engine reaches a specific region, the intake air flows not only in the forward direction but also in the reverse direction due to the pulsation, and the reverse flow phenomenon occurs. Repeated periodically.

  For this reason, in order to measure the amount of intake air taken into the internal combustion engine, not only the flow rate during forward flow but also the flow rate during reverse flow is measured and taken into the internal combustion engine from both forward flow and reverse flow rates. It is desirable to determine the amount of intake air. In view of this, a flow rate measuring apparatus is known that takes in the gas to be measured from the outlet into the auxiliary passage at the time of reverse flow and makes it sensitive to the flow rate sensor, and can measure the flow rate even at the time of reverse flow.

And in the flow measuring device which can measure the flow at the time of backflow, in order to improve the measurement accuracy, a configuration is known in which a ridge is provided on the downstream side of the outlet to restrict the inflow of intake air at the time of backflow (for example, , See Patent Document 1).
In other words, according to the flow rate measuring device of Patent Document 1, the outlet opens toward the downstream side in the flow direction of the main passage. Further, the gas to be measured that flows out from the outlet during forward flow flows in the same direction as the flow of the main passage along the plane of the outer wall of the housing. Further, a bulge exists on the downstream side of the outlet in the plane of the outer wall of the housing, and the bulge restricts the inflow of intake air during backflow.

  However, as for the shape of the bulge in Patent Document 1, the downstream surface rises perpendicular to the plane of the outer wall of the housing. For this reason, at the time of reverse flow, separation of the flow is likely to occur near the top of the bulge, and the amount of inflow into the sub-passage is insufficient. As a result, depending on the operating state of the internal combustion engine, the measurement accuracy may be reduced.

JP 2013-019674 A

  The present invention has been made in order to solve this problem, and the object of the present invention is to eliminate the state in which the amount of gas to be measured flowing into the auxiliary passage is insufficient at the time of backflow in the flow rate measurement device, thereby improving measurement accuracy. It is in suppressing the decrease.

  The flow rate measuring device according to the first invention of the present application is inserted into the main passage through a hole provided in a pipe forming the main passage and fixed, and generates a signal corresponding to the flow rate of the gas to be measured in the main passage. Body and flow sensor. First, the housing has a sub-passage through which the gas to be measured flowing through the main passage flows and is inserted into the main passage. The flow sensor generates a signal corresponding to the flow rate of the gas to be measured flowing through the main passage by heat transfer with the gas to be measured that is disposed in the sub passage and flows through the sub passage. Here, the direction connecting the upstream end and the downstream end is defined as the reference direction in the seal portion that prevents leakage of the gas to be measured in the hole in the housing.

An outlet for returning the gas to be measured that has passed through the flow sensor from the sub-passage to the main passage is opened toward the downstream side in the reference direction on the outer wall of the housing. There is a ridge on the side. Further, when the exit and the ridge are projected on a projection plane perpendicular to the reference direction, the exit and the ridge partially overlap on the projection plane.
Then, with respect to the upstream end, the downstream end and the top of the ridge, an angle θ1 formed between the direction from the upstream end to the top and the reference direction, and formed between the direction from the downstream end to the top and the reference direction If the angle θ2 is assumed, the relationship θ1 <θ2 <90 ° is established.

  Thereby, it is possible to suppress the occurrence of flow separation near the top of the ridge during backflow. For this reason, in the flow rate measuring device, it is possible to eliminate a state where the amount of the gas to be measured flowing into the sub-passage is insufficient at the time of backflow, and to suppress a decrease in measurement accuracy.

  Further, according to the flow measuring device of the second invention of the present application, the top of the ridge is a flat top surface, and the top surface is a line segment in a cross section that is parallel to the reference direction and drawn so as to cut the top surface. It is. Then, with respect to the upstream end, the downstream end, and the midpoint of the line segment, the angle θ3 formed between the direction from the upstream end toward the midpoint of the line segment and the reference direction, and the line segment from the downstream end Assuming an angle θ4 formed between the direction toward the midpoint and the reference direction, the relationship θ3 <θ4 <90 ° is established.

  Further, according to the flow measuring device of the third invention of the present application, there is a column body on the downstream side of the outlet, and when the outlet and the column body are projected onto a projection plane perpendicular to the reference direction, The column overlaps partly. Furthermore, in a specific cross section perpendicular to the longitudinal direction of the exit on the projection plane, two apexes projecting perpendicular to the reference direction, an upstream end projecting upstream, and a downstream end projecting downstream Exists. In the specific cross section, assuming an angle θ5 formed between the two apexes and the upstream end, and an angle θ6 formed between the two apexes and the downstream end, the relationship θ5 <θ6 <90 ° is established.

Furthermore, according to the flow measuring device of the fourth invention of the present application, the sub-passage has a straight path extending from the outlet in the direction opposite to the reference direction, and the columnar body exists in the straight path.
In the second to fourth inventions of the present application, the same effects as those of the first invention of the present application can be obtained.

(A) is a side view of a flow measuring device, (b) is a rear view of a flow measuring device (Example 1). It is II-II sectional drawing of FIG. 1 which shows the principal part of a flow measuring apparatus (Example 1). It is explanatory drawing which shows the reference | standard direction of a flow measuring device (Example 1). 10 is a bar graph showing evaluation results of measurement errors when the magnitude relationship between the angles θ1 and θ2 is changed (Example 1). It is a bar graph which shows the evaluation result of the measurement error when changing the distance of an exit and a protrusion (Example 1). (Example 2) which is sectional drawing which shows the principal part of a flow measuring device. (Example 3) which is sectional drawing which shows the principal part of a flow measuring device. (Example 4) which is sectional drawing which shows the principal part of a flow measuring device. (A) is a side view of a flow measuring device, (b) is a rear view of a flow measuring device (Example 5). (Example 5) which is XX sectional drawing of FIG. 9 which shows the principal part of a flow measuring device. (Example 6) which is a side view of a flow measuring device. (A) is a front view of a flow measuring device, (b) is a rear view of a flow measuring device (Example 6). FIG. 13 is a sectional view taken along line XIII-XIII in FIG. 11 showing a main part of the flow rate measuring device (Example 6). (Example 7) which is a side view of a flow measuring device. (A) is a front view of a flow measuring device, (b) is a rear view of a flow measuring device (Example 7). FIG. 15 is a cross-sectional view taken along the line XVI-XVI of FIG. 14 showing a main part of the flow rate measuring device (Example 7). (Example 8) which is a side view of a flow measuring device. (A) is a front view of a flow measuring device, (b) is a rear view of a flow measuring device (Example 8). FIG. 18 is a sectional view taken along line XIX-XIX in FIG. (Example 9) which is a front view of a flow measuring device. (Example 9) which is a rear view of a flow measuring device. (Example 9) which is XXII-XXII sectional drawing of FIG. FIG. 23 is an explanatory diagram showing the reference direction of the flow rate measuring device using the XXIII-XXIII cross section of FIG. 22 (Example 9). It is sectional drawing which shows the principal part of a flow measuring device (modification). It is sectional drawing which shows the principal part of a flow measuring device (modification). It is sectional drawing which shows the principal part of a flow measuring device (modification).

  Hereinafter, modes for carrying out the invention will be described based on examples. In addition, an Example discloses a specific example, and it cannot be overemphasized that this invention is not limited to an Example.

[Configuration of Example 1]
The flow rate measuring device 1 according to the first embodiment measures the flow rate of a gas to be measured as a measurement target using a thermal measurement principle.
Further, in the following description, a mode in which the flow rate measuring device 1 is inserted and fixed to the main passage 2 through which intake air flows in order to measure the flow rate of intake air taken into the internal combustion engine will be exemplified. In the main passage 2, when the operating state of the internal combustion engine is in a specific region, the intake air flows not only in the forward direction toward the internal combustion engine but also in the reverse direction due to pulsation, and the reverse flow phenomenon occurs periodically. Repeated.

As shown in FIG. 1, the flow rate measuring device 1 includes a housing 3 and a flow rate sensor 4.
That is, the housing 3 has a sub-passage 5 in which intake air flowing through the main passage 2 is taken in and flows, and the flow rate sensor 4 is disposed in the sub-passage 5 by heat transfer with the intake air flowing through the sub-passage 5. A signal corresponding to the flow rate in the main passage 2 is generated. Then, the flow measuring device 1 returns the intake air that has passed through the flow sensor 4 from the outlet 6 of the sub passage 5 to the main passage 2. The signal generated by the flow sensor 4 is subjected to predetermined processing and is output from the flow measurement device 1 to an external electronic control device (not shown; hereinafter sometimes referred to as ECU), for example, fuel It is used for various control processes such as injection control.

Hereinafter, the housing 3 will be described in detail.
The flow sensor 4 includes, for example, a predetermined semiconductor chip and a heating element, a temperature sensing element, and the like formed on the surface of the semiconductor chip. The flow sensor 4 is held by a resin frame 7 and protrudes into the sub passage 5. ing.

  The housing 3 is provided with, for example, resin as a raw material, and is mainly attached to a passage constituting portion 9 that has a sub passage 5 and projects into the main passage 2 and a pipe 10 that forms the main passage 2. Attached portion 11 to be fixed.

  The passage component 9 is inserted into the main passage 2 from a circular hole 10 a provided in the pipe 10, and the mounted portion 11 has a seal portion 11 a that seals between the main passage 2 and the outside of the pipe 10. Have. The seal portion 11a according to the first embodiment is configured by attaching an O-ring 11c to a circular groove 11b provided in the attached portion 11, and the O-ring 11c is provided between the main passage 2 and the outside of the pipe 10. Is substantially sealed.

  Here, as shown in FIG. 3, the direction of a line connecting the upstream end 11up and the downstream end 11dn of the seal portion 11a is defined as a reference direction α. Further, the reference direction α is the same as the direction of the line connecting the upstream end 10up and the downstream end 10dn of the hole 10a, and further, the flow path axis in the region of the main passage 2 where the flow rate measuring device 1 exists. The same direction as the direction.

  The channel | path structure part 9 is shape | molded by the substantially rectangular parallelepiped whose external shape is a rectangular plate shape. And the channel | path structure part 9 protrudes in the main channel | path 2 so that two rectangular surfaces with the largest area among the surfaces which make a substantially rectangular parallelepiped may become parallel to the reference direction (alpha) at the time of the forward flow of the main channel | path 2. (Hereinafter, two rectangular surfaces having the largest area among the surfaces forming a substantially rectangular parallelepiped may be referred to as side surfaces 12). In addition, the passage component 9 protrudes into the main passage 2 so that the longitudinal direction a of the side surface 12 is perpendicular to the reference direction α and the short direction b of the side surface 12 is parallel to the reference direction α. ing.

  Moreover, in the channel | path structure part 9, the subchannel | path 5 becomes a channel | path structure which has the following 1st, 2nd channel | paths 13 and 14. FIG. That is, the first passage 13 guides the intake air so that the streamline of the flow from the intake air inlet 15 toward the outlet 16 different from the outlet 6 draws a gentle curved arc. The second passage 14 is branched from the first passage 13, and a part of the flow of the intake air flowing into the first passage 13 from the inlet 15 is diverted and circulated, and is returned from the outlet 6 to the main passage 2. Is.

  Here, the inlet 15 opens toward the upstream side at the elongated end surface 17 disposed on the upstream side with respect to the reference direction α, and is perpendicular to the reference direction α. Further, the second passage 14 is branched into two on the downstream side of the flow sensor 4, and the outlet 6 exists on each side surface 12. Note that the outlet 16 is a side disposed on the side opposite to the end face 17 in the reference direction α, and is open toward the downstream side with respect to the reference direction α and toward the outer peripheral side of the main passage 2.

  As described above, in the passage component 9, part of the intake air flowing into the first passage 13 from the inlet 15 flows into the second passage 14 through the flow sensor 4 and passes through the flow sensor 4 during forward flow. The intake air is divided into two flows and returns from the outlet 6 to the main passage 2. Further, during reverse flow, the intake air that has flowed into the second passage 14 from the two outlets 6 merges and passes through the flow sensor 4, and the intake air that has passed through the flow sensor 4 flows into the first passage 13 and enters the inlet Return to main passage 2 from 15.

Therefore, the flow rate measuring device 1 can measure not only the flow rate in the main passage 2 at the time of forward flow but also the flow rate at the time of reverse flow. The amount of intake air can be determined.
Of the intake air that flows into the first passage 13 from the inlet 15 during forward flow, the intake air that flows through the first passage 13 without flowing into the second passage 14 returns from the outlet 16 to the main passage 2. A portion of the first passage 13 downstream of the branch port with respect to the second passage 14 suppresses the dust flowing in from the inlet 15 together with the intake air toward the second passage 14, and the flow sensor 4 Has the function of preventing damage from dust.

[Features of Example 1]
According to the flow measuring device 1 of the first embodiment, as shown in FIGS. 1 to 2, each side surface 12 of the housing 3 has a plane 19 arranged in parallel to the reference direction α. In the plane 19, there is an opening (not shown) of the second passage 14. Then, by covering this opening with the cover 20, the outlet 6 is formed between the cover 20 and the flat surface 19, and the outlet 6 opens toward the downstream side in the reference direction α. For this reason, the intake air flowing out from the outlet 6 flows along the plane 19 in the reference direction α.

  On the plane 19, a ridge 21 exists on the downstream side of the outlet 6. The ridges 21 are linear parallel to the longitudinal direction a, and the height h of the ridges 21 from the plane 19 is the outlet 6 in the direction perpendicular to the plane 19 (hereinafter sometimes referred to as the ridge direction β). It is higher than the width W. Further, when the exit 6 and the ridge 21 are projected onto the projection plane A perpendicular to the reference direction α, the exit 6 and the ridge 21 partially overlap on the projection plane A. More specifically, on the projection plane A, the exit 6 is included in the ridge 21 with respect to the range in the longitudinal direction a, and the exit 6 is included in the ridge 21 with respect to the range in the ridge direction β.

  The apex 23 of the ridge 21 is a line parallel to the longitudinal direction a, and the upstream end 24 and the downstream end 25 with respect to the reference direction α are also parallel to the longitudinal direction a. A plane 26 is inclined between the upstream end 24 and the apex 23 by an angle θ1 with respect to the reference direction α, and an angle θ2 is inclined between the downstream end 25 and the apex 23 with respect to the reference direction α. This is a flat surface 27.

In other words, the angles θ1 and θ2 are expressed in another way in the specific cross section B perpendicular to the plane 19 and parallel to the reference direction α in the cross section of the ridge 21. The angle θ <b> 2 is formed between the direction from the downstream end 25 toward the top 23 and the plane 19.
A relationship of θ1 <θ2 <90 ° is established between the angles θ1 and θ2.

[Effect of Example 1]
According to the flow rate measuring apparatus 1 of the first embodiment, the flat surface 19 that forms the outer wall of the housing 3 exists, and the flat surface 19 is parallel to the reference direction α. Further, the outlet 6 opens toward the downstream side in the reference direction α so that the intake air flowing out from the outlet 6 flows in the reference direction α along the plane 19. Further, a ridge 21 exists on the plane 19 on the downstream side of the outlet 6. Furthermore, the exit 6 and the ridge 21 partially overlap in the projection plane.

In the specific cross section B of the ridge 21, with respect to the top 23, the upstream end 24, and the downstream end 25 of the ridge 21, an angle θ <b> 1 formed between the direction from the upstream end 24 toward the top 23 and the reference direction α, downstream Assuming an angle θ2 formed between the direction from the end 25 toward the apex 23 and the reference direction α, the relationship θ1 <θ2 <90 ° is established.
Thereby, it is possible to suppress the occurrence of separation of the flow in the vicinity of the top 23 of the ridge 21 during the backflow. For this reason, in the flow measurement device 1, it is possible to eliminate a state where the inflow amount of the intake air into the sub-passage 5 is insufficient at the time of backflow, thereby suppressing a decrease in measurement accuracy.

That is, as shown in FIG. 4, when the measurement error is investigated by changing the magnitude relationship between the angles θ1 and θ2 in a range where the angles θ1 and θ2 are smaller than 90 °, when the angle θ1 is equal to or smaller than the angle θ2, the angle θ1 is It was confirmed that the measurement error was significantly smaller than when the angle was larger than the angle θ2.
As shown in FIG. 5, in the ridge 21 where the relationship of θ1 <θ2 <90 ° is established, even if the distance F between the outlet 6 and the upstream end 24 is changed, the measurement error is kept small and almost constant. It was also confirmed that there was no fluctuation.

[Example 2]
According to the flow rate measuring device 1 of the second embodiment, the ridge 21 is a line parallel to the longitudinal direction “a”, like the ridge 21 of the first embodiment, and the top 23, the upstream end 24, and the downstream end 25 of the ridge 21. Is a line parallel to the longitudinal direction a.
And according to the ridge 21 of Example 2, unlike the ridge 21 of Example 1, as shown in FIG. 6, between the upstream end 24 and the top 23 and between the downstream end 25 and the top 23, , Respectively, are curved surfaces 29 and 30 that are convex in the rising direction β, and the curved surfaces 29 and 30 are smoothly continuous at the apex 23.
As in the first embodiment, the relationship θ1 <θ2 <90 ° is established for the angles θ1 and θ2. For this reason, the same effect as Example 1 can be acquired.

Example 3
According to the flow rate measuring device 1 of the third embodiment, the ridge 21 is a line parallel to the longitudinal direction a, like the ridge 21 of the first embodiment, and the top 23, the upstream end 24, and the downstream end 25 of the ridge 21. Is a line parallel to the longitudinal direction a.
And according to the bump 21 of Example 3, unlike the bump 21 of Example 1, as shown in FIG. 7, between the upstream end 24 and the top 23 and between the downstream end 25 and the top 23, , Respectively, are curved surfaces 31 and 32 that are concave in the direction opposite to the bulging direction β.
As in the first embodiment, the relationship θ1 <θ2 <90 ° is established for the angles θ1 and θ2. For this reason, the same effect as Example 1 can be acquired.

Example 4
According to the flow rate measuring device 1 of the fourth embodiment, the ridge 21 is a line parallel to the longitudinal direction a, and the upstream end 24 and the downstream end 25 of the ridge 21 are longitudinal. A line parallel to the direction a.
Then, according to the bump 21 of the fourth embodiment, unlike the bump 21 of the first embodiment, as shown in FIG. 8, the top 23 of the bump 21 is a flat top surface 23 平行 that is flat and parallel to the plane 19. For this reason, the top surface 23 に お い て is a line segment in the specific cross section B of the ridge 21.

Further, regarding the upstream end 24, the downstream end 25, and the midpoint 34m of the line segment, an angle θ3 formed between the direction from the upstream end 24 toward the midpoint 34m and the reference direction α, and the midpoint from the downstream end 25 Assuming an angle θ4 formed between the direction toward the point 34m and the reference direction α, the relationship θ3 <θ4 <90 ° is established. For this reason, the same effect as Example 1 can be acquired.
In addition, between the upstream end 24 and the top surface 23 、, and between the downstream end 25 and the top surface 23 で, respectively, are curved surfaces 35 and 36 that protrude in the rising direction β, and the curved surfaces 35 and 36 are respectively At the upstream end and the downstream end of the top surface 23Α, the top surface 23Α is smoothly continuous.

Example 5
According to the flow measuring device 1 of the fifth embodiment, the ridge 21 has the same shape as the ridge 21 of the first embodiment.
And according to the bump 21 of Example 5, unlike the bump 21 of Example 1, as shown in FIG.9 and FIG.10, two bumps 21 exist, and each bump 21 is long in the longitudinal direction a. Is shorter than the ridge 21 of the first embodiment. The two ridges 21 are arranged in the longitudinal direction a. That is, the configuration of the ridge 21 of the fifth embodiment is a mode in which the ridge 21 of the first embodiment is divided at the center in the longitudinal direction a. For this reason, the same effect as Example 1 can be acquired.

Example 6
According to the flow rate measuring apparatus 1 of the sixth embodiment, as shown in FIGS. 11 to 13, the passage constituting portion 9 is formed into a substantially straight body having a rectangular plate shape as in the first embodiment. The direction b projects into the main passage 2 so as to be parallel to the reference direction α. The sub-passage 5 is a straight path 38 that passes through the straight line between the inlet 15 and the outlet 6 in parallel with the short direction b, and the flow rate sensor 4 protrudes from the straight path 38. The outlet 6 and the inlet 15 have the same rectangular shape that is long in the longitudinal direction a, and overlap each other when projected onto a projection plane that is perpendicular to the reference direction α.

In addition, the inlet 15 opens toward the upstream side at the elongated end surface 39 disposed on the upstream side in the reference direction α, and the outlet 6 opens on the end surface 40 opposite to the end surface 39 with respect to the reference direction α. , Opening toward the downstream side. And the direction of the flow of the intake air in the straight path 38 is the same as the reference direction α in both the forward flow and the reverse flow.
As described above, the flow rate measuring device 1 according to the sixth embodiment can measure not only the flow rate in the main passage 2 during the forward flow but also the flow rate during the reverse flow as in the first embodiment. From both flow rates, the amount of intake air taken into the internal combustion engine can be determined.

  Further, according to the flow rate measuring device 1 of the sixth embodiment, the housing 3 has the column body 41 disposed on the downstream side of the outlet 6. Here, the column body 41 is a quadrangular column extending in parallel with the longitudinal direction a. The column body 41 has two apexes 42 projecting perpendicular to the reference direction α, an upstream end 43 projecting upstream, and a downstream end 44 projecting downstream, and the two apexes 42, upstream end 43 and the downstream end 44 are line segments parallel to the longitudinal direction a. Further, when the column body 41 and the outlet 6 are projected onto the projection plane Α, the outlet 6 and the column body 41 partially overlap on the projection plane Α. More specifically, in the projection plane に 関 し, the outlet 6 and the column 41 substantially coincide with each other with respect to the range in the longitudinal direction a, and the column 41 is included in the outlet 6 with respect to the range in the direction in which the top 42 protrudes.

And in the specific cross section B perpendicular | vertical to the longitudinal direction a among the cross sections of the column 41, it forms with the angle (theta) 5 formed by the two tops 42 and the upstream end 43, and the two tops 42 and the downstream end 44. Assuming an angle θ6, the relationship θ5 <θ6 <90 ° is established. For this reason, the same effect as Example 1 can be acquired.
The column body 41 is supported by two support portions 45 extending from the end face 40 to the downstream side in the reference direction α. Further, considering another cross section C including the upstream end 43 and the downstream end 44 separately from the specific cross section B, the column 41 has a plane symmetry with another cross section C as a symmetry plane, and the two apexes 42 are defined as a reference. It exists at the same position with respect to the direction α.

Example 7
According to the flow measurement device 1 of the seventh embodiment, as shown in FIGS. 14 to 16, the housing 3, the sub passage 5, and the column body 41 are respectively the housing 3, the sub passage 5, and the column of the sixth embodiment. It has the same shape as the body 41.
The column body 41 of the seventh embodiment partially exists in the sub-passage 5. Specifically, the upstream end 43 of the upstream portion of the reference direction α with respect to the two apexes 42 is formed. A part including the same exists in the auxiliary passage 5. Thereby, the same effect as Example 1 can be acquired.

Example 8
According to the flow measurement device 1 of the eighth embodiment, as shown in FIGS. 17 to 19, the housing 3, the sub passage 5, and the column body 41 are respectively the housing 3, the sub passage 5, and the column of the sixth embodiment. It has the same shape as the body 41.
The entire column 41 of the eighth embodiment exists in the sub passage 5. Thereby, the same effect as Example 1 can be acquired.

Example 9
According to the flow rate measuring device 1 of the ninth embodiment, as shown in FIGS. 20 to 23, the auxiliary passage 5 is provided so as to circulate all the flow of the intake air taken in. In addition, the outlet 6 and the inlet 15 have a rectangular shape that is long in the longitudinal direction “a”, and the inlet 15 is biased to overlap with one side of the outlet 15 when projected onto a projection plane that is perpendicular to the reference direction α. That is, when the third direction c perpendicular to both the longitudinal direction a and the short direction b is considered, the entrance 15 is biased to one side of the exit 6 in the third direction c on the projection plane A (see FIG. 20 and FIG. 21).

Moreover, the housing | casing 3 has the pillar 41 of the shape similar to Examples 6-8, and the pillar 41 protrudes outside the sub channel | path 5 from the exit 6 partially. Specifically, a portion including the downstream end 44 of the portion on the downstream side in the reference direction α from the two apexes 42 exists outside the sub-passage 5. Further, the column body 41 is present on the other side in the third direction c in the outlet 6.
As described above, the same effects as those of the first embodiment can be obtained.

  Furthermore, in Example 9, the hole 10a is rectangular, and the opening edge of the hole 10a is uniformly raised on the outer surface of the pipe 10 to form a rectangular tube 10b. Moreover, the to-be-attached part 11 has the collar part 11d which can cover the front end surface of the cylinder 10b. A rectangular ring 11e made of an elastic material such as rubber is placed on the distal end surface of the cylinder 10b, and the ring 11e is sandwiched between the cylinder 10b and the flange part 11d to constitute the seal part 11a.

  In Example 9, as shown in FIG. 23, the upstream end 11up and the downstream end 11dn of the seal portion 11a and the upstream end 10up and the downstream end 10dn of the hole 10a are line segments. The reference direction α can be defined as the direction of a straight line connecting the midpoints of the upstream end 11up and the downstream end 11dn. Further, the reference direction α is the same as the direction of the straight line connecting the midpoints of the upstream end 10up and the downstream end 10dn, and further, the flow path axis in the region where the flow rate measuring device 1 exists in the main passage 2. The same direction as the direction.

[Modification]
Various modifications can be considered for the present invention without departing from the gist thereof.
That is, aspects, such as the housing | casing 3 of the flow volume measuring apparatus 1, the channel | path structure part 9, the subchannel | path 5, the protruding part 21, and the column 41, are not limited to an Example, Various aspects can be taken.
In the first to eighth embodiments, the flow measuring device 1 is illustrated as being disposed in the main passage 2 through which the intake air flows in order to measure the flow rate of the intake air sucked into the internal combustion engine. The mode of use of the device 1 is not limited to this.

  Moreover, according to the flow measuring device 1 of Examples 1-5, although the bump 21 existed in the plane 19 parallel to the reference direction (alpha), the surface where the bump 21 exists is not limited to such an aspect. For example, the outer wall on the downstream side of the outlet 6 may be a curved surface 19A, and a ridge 21 may be provided on the curved surface 19A (see FIG. 24), and the inclined outer surface on the downstream side of the outlet 6 is inclined with respect to the reference direction α. 19B, and the ridge 21 may be provided on the inclined surface 19B (see FIG. 25). Further, the outer wall on the downstream side of the outlet 6 is composed of the curved surface 19A and the inclined surface 19B, and the curved surface 19A and the inclined surface 19B. A ridge 21 may be provided so as to straddle both (see FIG. 26).

  Furthermore, according to the flow rate measuring apparatus 1 of the embodiment, the seal portion 11a substantially seals between the main passage 2 and the outside of the pipe 10 by the O-ring 11b and the ring 11e. The aspect of the seal is not limited to such an aspect. For example, in the flow rate measuring device 1 according to the ninth embodiment, the seal portion 11a may be configured to seal between the main passage 2 and the outside of the pipe 10 by welding the tube 10b and the flange portion 11d.

DESCRIPTION OF SYMBOLS 1 Flow measuring device 2 Main passage 3 Case 4 Flow sensor 5 Sub passage 6 Outlet 10 Piping 10a Hole 11a Seal part 21 Bump 投影 Projection surface 23 Top 24 Upstream end 25 Downstream end α Reference direction θ1, θ2 Angle

Claims (7)

A flow measuring device that is inserted into and fixed to the main passage from a hole (10a) provided in the pipe (10) forming the main passage (2) and generates a signal corresponding to the flow rate of the gas to be measured in the main passage. In (1),
A housing (3) having a sub-passage (5) through which the gas to be measured flowing through the main passage flows and flows, and inserted into the main passage;
A flow sensor (4) that generates a signal corresponding to the flow rate of the gas to be measured in the main passage by heat transfer with the gas to be measured that is arranged in the sub passage and flows through the sub passage;
In the seal portion (11a) that prevents leakage of the gas to be measured in the hole in the casing, the direction connecting the upstream end and the downstream end is defined as a reference direction (α).
On the outer wall of the housing, an outlet (6) for returning the gas to be measured that has passed through the flow sensor from the sub-passage to the main passage is opened toward the downstream side in the reference direction. On the outer wall of the body there is a ridge (21) downstream of the outlet,
When the exit and the ridge are projected onto a projection plane (Α) perpendicular to the reference direction, the exit and the ridge partially overlap on the projection plane,
With respect to the upstream end (24), the downstream end (25) and the top (23) of the ridge, an angle θ1 formed between a direction from the upstream end toward the top and the reference direction, and from the downstream end to the top Assuming an angle θ2 formed between the direction toward the apex and the reference direction, a flow rate measuring device satisfying the relationship θ1 <θ2 <90 °. The flow measurement device according to claim 1,
The apex is included in a curved surface that protrudes toward the protruding side. In the flow measuring device that is inserted and fixed to the main passage from the hole provided in the pipe forming the main passage, and generates a signal corresponding to the flow rate of the gas to be measured in the main passage,
A housing having a sub-passage through which the gas to be measured flowing through the main passage flows and is inserted into the main passage;
A flow rate sensor that generates a signal according to the flow rate of the gas to be measured in the main passage by heat transfer with the gas to be measured that is arranged in the sub passage and flows through the sub passage;
In the seal part that prevents leakage of the gas to be measured in the hole in the casing, the direction connecting the upstream end and the downstream end is defined as a reference direction.
An outlet for returning the gas to be measured that has passed through the flow sensor from the sub-passage to the main passage opens toward the downstream side in the reference direction on the outer wall of the housing, and further, the outer wall of the housing Have a ridge downstream of the outlet, the top of which is a flat top surface (23 cm),
When the exit and the ridge are projected onto a projection plane (Α) perpendicular to the reference direction, the exit and the ridge partially overlap on the projection plane,
In the cross section drawn to be parallel to the reference direction and cut along the top surface, the top surface is a line segment, and the upstream end, the downstream end, and the midpoint (34 m) of the line segment of the ridge The angle θ3 formed between the direction from the upstream end toward the midpoint of the line segment and the reference direction, the direction from the downstream end toward the midpoint of the line segment, and the reference direction Assuming an angle θ4 formed therebetween, a flow rate measuring device characterized by the relationship θ3 <θ4 <90 °. In the flow measurement device according to any one of claims 1 to 3,
A plurality of the ridges exist,
The plurality of ridges are arranged in a direction (a) perpendicular to the reference direction. In the flow measuring device that is inserted and fixed to the main passage from the hole provided in the pipe forming the main passage, and generates a signal corresponding to the flow rate of the gas to be measured in the main passage,
A housing having a sub-passage through which the gas to be measured flowing through the main passage flows.
A flow rate sensor that generates a signal corresponding to the flow rate of the gas to be measured flowing through the main passage by heat transfer with the gas to be measured that is disposed in the sub passage and flows through the sub passage;
In the seal part that prevents leakage of the gas to be measured in the hole in the casing, the direction connecting the upstream end and the downstream end is defined as a reference direction.
The outlet of the sub passage opens toward the downstream side of the reference direction so that the gas to be measured flowing out of the outlet flows in the reference direction,
There is a column (41) downstream of the outlet,
When the exit and the column are projected onto a projection plane perpendicular to the reference direction, the exit and the column partially overlap on the projection plane,
Among the cross sections of the column bodies, in a specific cross section perpendicular to the longitudinal direction of the column bodies on the projection plane, two peaks (42) projecting perpendicular to the reference direction, and an upstream end (43) projecting upstream And there is a downstream end (44) protruding downstream,
Furthermore, in the specific cross section, assuming an angle θ5 formed between the two apexes and the upstream end and an angle θ6 formed between the two apexes and the downstream end, a relationship of θ5 <θ6 <90 ° is assumed. A flow rate measuring device characterized by the fact that The flow rate measuring device according to claim 5,
The flow rate measuring apparatus according to claim 1, wherein the column body partially exists in the sub-passage. In the flow measuring device that is inserted and fixed to the main passage from the hole provided in the pipe forming the main passage, and generates a signal corresponding to the flow rate of the gas to be measured in the main passage,
A housing having a sub-passage through which the gas to be measured flowing through the main passage flows.
A flow rate sensor that generates a signal corresponding to the flow rate of the gas to be measured flowing through the main passage by heat transfer with the gas to be measured that is disposed in the sub passage and flows through the sub passage;
In the seal part that prevents leakage of the gas to be measured in the hole in the casing, the direction connecting the upstream end and the downstream end is defined as a reference direction.
The outlet of the sub passage opens toward the downstream side of the reference direction so that the gas to be measured flowing out of the outlet flows in the reference direction,
The secondary passage has a straight path (38) extending from the outlet in a direction opposite to the reference direction,
There is a pillar in this straight path,
When the exit and the column are projected onto a projection plane perpendicular to the reference direction, the exit and the column partially overlap on the projection plane,
Among the cross sections of the pillars, in a specific cross section perpendicular to the longitudinal direction of the pillars on the projection plane, two peaks projecting perpendicular to the reference direction, an upstream end projecting upstream, and a downstream side There is a protruding downstream end,
Furthermore, in the specific cross section, assuming an angle θ5 formed between the two apexes and the upstream end and an angle θ6 formed between the two apexes and the downstream end, a relationship of θ5 <θ6 <90 ° is assumed. A flow rate measuring device characterized by the fact that