WO2022107426A1 - 物理量検出装置 - Google Patents
物理量検出装置 Download PDFInfo
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- WO2022107426A1 WO2022107426A1 PCT/JP2021/032927 JP2021032927W WO2022107426A1 WO 2022107426 A1 WO2022107426 A1 WO 2022107426A1 JP 2021032927 W JP2021032927 W JP 2021032927W WO 2022107426 A1 WO2022107426 A1 WO 2022107426A1
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- physical quantity
- flow rate
- chamber
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- 238000001514 detection method Methods 0.000 title claims abstract description 40
- 230000002093 peripheral effect Effects 0.000 claims 1
- 238000005259 measurement Methods 0.000 description 28
- 230000000694 effects Effects 0.000 description 9
- 238000009423 ventilation Methods 0.000 description 8
- 238000002485 combustion reaction Methods 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- 230000002238 attenuated effect Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
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- 239000000463 material Substances 0.000 description 3
- 229920003002 synthetic resin Polymers 0.000 description 3
- 239000000057 synthetic resin Substances 0.000 description 3
- 239000004642 Polyimide Substances 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 238000009530 blood pressure measurement Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 229920001721 polyimide Polymers 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
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- 239000007769 metal material Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F5/00—Measuring a proportion of the volume flow
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
- G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
- G01F1/6842—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow with means for influencing the fluid flow
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
- G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
- G01F1/6845—Micromachined devices
Definitions
- the present invention relates to, for example, a physical quantity detecting device for detecting a physical quantity of intake air of an internal combustion engine.
- Patent Document 1 describes a bypass flow path that takes in a part of the air flowing through the main flow path formed in the duct, and a sub-bypass flow path that branches from the bypass flow path and takes in a part of the air flowing through the bypass flow path. Is formed inside, and the structure of the air flow measuring device in which the sensor is installed in the sub-bypass flow path is shown.
- the sensor has a diaphragm that detects the flow rate, and the element surface of the diaphragm is exposed to the sub-bypass flow path, and the back surface of the element of the diaphragm is exposed to the closed chamber that communicates with the circuit chamber through the ventilation hole. is doing.
- the physical quantity detection device is required to have the ability to accurately measure the flow rate signal even if it is installed in various types of internal combustion engines.
- the sound pressure generated by the turbocharger mounted downstream of the physical quantity detection device of the internal combustion engine affects the flow rate characteristics of the physical quantity detection device.
- the resonance phenomenon of sound pressure on the element front side and the element back side of the diaphragm by the turbocharger affects the flow rate characteristics and causes a flow rate detection error.
- a flow rate detection error occurs due to the sound pressure.
- the present invention has been made in view of the above points, and an object of the present invention is to provide a physical quantity detecting device capable of suppressing the influence of the resonance phenomenon of sound pressure on the flow rate characteristics.
- the physical quantity detection device of the present invention that solves the above problems is A physical quantity detection device that detects the physical quantity of the gas to be measured flowing through the main passage.
- a housing arranged in the main passage, a sub-passage formed in the housing, a flow detection unit arranged in the sub-passage, a circuit unit electrically connected to the flow detection unit, and the above-mentioned
- a circuit chamber formed in a housing and accommodating the circuit portion, and one end of the sub-passageway and the other end of the sub-passageway open to the circuit chamber to communicate between the sub-passageway and the circuit chamber, and the sub-passageway.
- a first pressure introduction passage capable of introducing the pressure of the gas to be measured is provided in the circuit chamber.
- the flow rate detection unit includes a diaphragm in which the surface of the diaphragm is exposed in the sub-passage and the back surface of the diaphragm is exposed in the closed chamber isolated from the sub-passage, and one end is opened in the circuit chamber and the other end is in the closed chamber. It has a second pressure introduction passage that opens to communicate between the circuit chamber and the closed chamber and can introduce the pressure of the gas to be measured from the circuit chamber to the closed chamber.
- the circuit chamber is characterized by having at least one or more protrusions provided at positions facing the opening at which the other end of the first pressure introduction passage opens.
- the present invention is to provide a physical quantity detection device capable of suppressing the influence of the resonance phenomenon of sound pressure on the flow rate characteristics.
- FIG. 2 is a cross-sectional view of the cover of FIG. 2 cut at a joint surface with a housing.
- FIG. 5 is a sectional view taken along line VI-VI of FIG. Sectional view of the chip package.
- Enlarged view of the main part of FIG. FIG. 5 is a sectional view taken along line VIII-VIII of FIG. Enlarged view of the main part of FIG.
- the embodiment for carrying out the invention solves various problems requested as an actual product, and particularly as a detection device for detecting a physical quantity of intake air of a vehicle. It solves various problems that are desirable for use and has various effects.
- One of the various problems solved by the following examples is the content described in the column of the problems to be solved by the above-mentioned invention, and one of the various effects of the following examples is. These are the effects described in the column of effects of the invention.
- the various problems solved by the following examples and the various effects produced by the following examples will be described in the description of the following examples. Therefore, the problems and effects described in the following examples are described in terms other than the contents of the problem column to be solved by the invention and the effect column of the invention.
- FIG. 1 is a system diagram showing an embodiment in which a physical quantity detection device according to the present invention is used in an electronic fuel injection type internal combustion engine system 1.
- the physical quantity detecting device of this embodiment is used in an internal combustion engine system 1 for an automobile.
- the internal combustion engine system 1 has an engine 2 with a turbocharger 15, and in the main passage 22, in order from the upstream side, an air cleaner 4, a physical quantity detection device 20, an intercooler 6, a throttle valve 7, and an intake pipe 8 are provided. Is provided, and the exhaust catalyst 10 is provided in the exhaust passage 9.
- a thermal humidity measuring device 11, an intake pressure sensor 12, and an intake temperature sensor 13 are attached to the intake pipe 8 to measure the humidity, pressure, and temperature of the intake air sucked into the engine 2.
- the physical quantity detection device 20 detects physical quantities such as the flow rate, temperature, humidity, and pressure of the gas to be measured, which is the intake air taken in from the air cleaner 4 and flows through the main passage 22.
- the physical quantity detected by the physical quantity detection device 20 is converted into an electric signal and input to the control device (ECU).
- the control device calculates the fuel injection amount and ignition timing of the engine 2 by using the physical quantity of the intake air which is the output of the physical quantity detection device 20.
- FIG. 2 is a front view of the physical quantity detecting device.
- the physical quantity detecting device 20 is used in a state of being inserted into the inside of the main passage 22 through an attachment hole provided in the passage wall of the main passage 22 and fixed to the main passage 22.
- the physical quantity detecting device 20 includes a housing arranged in the main passage 22 through which the gas to be measured flows.
- the housing of the physical quantity detecting device 20 has a housing 100 and a cover 200 attached to the housing 100.
- the housing 100 is formed, for example, by injection molding a synthetic resin material.
- the cover 200 is made of, for example, a plate-shaped member made of a metal material or a synthetic resin material, and in this embodiment, it is made of an injection-molded product made of an aluminum alloy or a synthetic resin material.
- the housing 100 includes a flange 111 for fixing the physical quantity detecting device 20 to the main passage 22, a connector 112 protruding from the flange 111 and exposed to the outside from the intake body for electrical connection with an external device, and a flange. It has a measuring unit 113 extending from 111 toward the center of the main passage 22.
- the measuring unit 113 has a thin and long shape extending straight from the flange 111, and has a wide front surface 121 and a back surface 122, and a pair of narrow side surfaces 123 and 124.
- the measuring unit 113 projects from the inner wall of the main passage 22 toward the center of the passage 22 in a state where the physical quantity detecting device 20 is attached to the main passage 22.
- the front surface 121 and the back surface 122 are arranged in parallel along the central axis of the main passage 22, and the side surface 123 on one side in the longitudinal direction of the measurement unit 113 among the narrow side surfaces 123 and 124 of the measurement unit 113 is the main passage 22.
- the side surface 124 on the other side in the lateral direction of the measuring unit 113 is arranged to face the downstream side of the main passage 22. With the physical quantity detecting device 20 attached to the main passage 22, the tip of the measuring unit 113 is the lower surface 125.
- the measurement unit 113 is provided with a sub-passage inlet 131 on the side surface 123, and a first outlet 132 and a second outlet 133 on the side surface 124.
- the sub-passage inlet 131, the first outlet 132, and the second outlet 133 are provided at the tip of the measuring unit 113 extending from the flange 111 toward the center of the main passage 22.
- the physical quantity detecting device 20 has a shape in which the measuring unit 113 extends long in a direction orthogonal to the center line of the main passage 22, but the widths of the side surfaces 123 and 124 have a narrow shape. As a result, the physical quantity detecting device 20 can suppress the fluid resistance to a small value with respect to the gas to be measured.
- FIG. 3 is a view showing a state in which the cover is removed from the housing of the physical quantity detection device
- FIG. 4 is a rear view of the cover
- FIG. 5 is a cross-sectional view of the cover of FIG. 2 cut at a joint surface with the housing.
- the longitudinal direction of the measuring unit 113 which is the direction in which the measuring unit 113 extends from the flange 111, is the Z axis, and the measuring unit is in the direction extending from the sub-passage inlet 131 of the measuring unit 113 toward the first exit 132.
- the short side direction of 113 may be referred to as an X axis
- the thickness direction of the measurement unit 113 which is a direction from the front surface 121 to the back surface 122 of the measurement unit 113, may be referred to as a Y axis.
- the measurement unit 113 of the housing 100 is provided with a flow rate sensor 411, which is a flow rate detection element, an intake air temperature sensor 321 and a humidity sensor 322.
- the flow rate sensor 411 is arranged in the middle of the passage of the sub-passage 134.
- the flow rate sensor 411 detects the flow rate of the gas to be measured flowing through the main passage.
- the intake air temperature sensor 321 is arranged in the middle of the passage of the temperature detection passage 136, one end of which is open near the sub-passage inlet 131 of the side surface 123 and the other end of which is open on both the front surface 121 and the back surface of the measurement unit 113.
- the intake air temperature sensor 321 detects the temperature of the gas to be measured flowing through the main passage.
- the humidity sensor 322 is arranged in the humidity measurement room 137 of the measurement unit 113.
- the humidity sensor 322 measures the humidity of the gas to be measured taken into the humidity measuring chamber 137 from the window portion 138 opening on the back surface of the
- the measurement unit 113 is provided with a sub-passage 134 and a circuit chamber 135 for accommodating the circuit board 300.
- the circuit chamber 135 and the sub-passage 134 have a structure in which the cover 200 is attached to the front surface 121 of the measuring unit 113 to cover and cover the circuit chamber 135 and the sub-passage 134 so as to be closed.
- the cover 200 has a flat plate shape that covers the front surface 121 of the measuring unit 113. As shown in FIG. 4, the cover 200 is provided with a rib 221 on the back surface. The rib 221 is formed along the adhesive portion with the measuring unit 113. As shown in FIG. 5, the measuring unit 113 is provided with a concave groove 141 on the front surface 121, and the rib 221 is inserted into the measuring unit 113. The cover 200 is adhered with an adhesive with the rib 221 inserted in the concave groove 141 of the measuring unit 113.
- the circuit chamber 135 is provided in a region on one side (side surface 123 side) in the X-axis direction, which is a position on the upstream side in the flow direction of the gas to be measured in the main passage 22.
- the sub-passage 134 has a region on the Z-axis direction tip side (lower surface 125 side) of the measurement unit 113 with respect to the circuit chamber 135 and a position on the main passage 22 on the downstream side in the flow direction of the measured gas with respect to the circuit chamber 135. It is provided over the region on the other side (side surface 124 side) in the X-axis direction.
- the sub-passage 134 has a first sub-passage A and a second sub-passage B that branches in the middle of the first sub-passage A.
- the first sub-passage A extends between the sub-passage inlet 131 that opens to the side surface 123 on one side of the measurement unit 113 and the first exit 132 that opens to the side surface 124 on the other side of the measurement unit 113. It has a configuration extending along the X-axis direction of 113.
- the first sub-passage A has a flow path extending from the sub-passage inlet 131 along the flow direction of the gas to be measured in the main passage 22 and connecting to the first outlet 132.
- the first sub-passage A can take in the gas to be measured flowing in the main passage 22 from the sub-passage inlet 131, and return the taken-in gas to be measured from the first outlet 132 to the main passage 22.
- the first sub-passage A is formed by covering the first sub-passage groove recessed in the front surface of the measuring unit 113 with the region 201 of the cover 200.
- the second sub-passage B branches at an intermediate position of the first sub-passage A, is bent toward the proximal end side (flange side) of the measuring unit 113, and extends along the Z-axis direction of the measuring unit 113. .. Then, the base end portion of the measurement unit 113 bends toward the other side (side surface 124 side) of the measurement unit 113 in the X-axis direction, makes a U-turn toward the tip end portion of the measurement unit 113, and again in the Z-axis direction of the measurement unit 113. It extends along.
- the second outlet 133 is arranged to face the downstream side in the flow direction of the gas to be measured in the main passage 22.
- the second outlet 133 has an opening area substantially equal to or slightly larger than that of the first outlet 132, and is formed at a position adjacent to the measurement unit 113 on the longitudinal proximal end side of the first outlet 132.
- the second sub-passage B has a flow path that reciprocates along the Z-axis direction of the measuring unit 113.
- the second sub-passage B branches in the middle of the first sub-passage A and extends toward the base end side (direction away from the first sub-passage A) of the measurement unit 113 and the outbound passage portion B1 for measurement.
- a return passage portion that is folded back at the base end portion side of the portion 113 (the end portion of the separation passage portion), makes a U-turn, and extends toward the tip portion side (direction approaching the first sub-passage A) of the measurement portion 113. Has B2.
- the return passage portion B2 is a flow path connected to a second outlet 133 that opens toward the downstream side in the flow direction of the measured gas at a position on the downstream side in the flow direction of the measured gas in the main passage 22 with respect to the sub-passage inlet 131.
- the second sub-passage B can be returned to the main passage 22 from the second outlet 133 by passing the gas to be measured that has flowed from the first sub-passage A.
- the second sub-passage B is formed by covering the second sub-passage groove 152 recessed in the front surface of the measuring unit 113 with the area 202 of the cover 200.
- a first introduction passage 161 capable of introducing the pressure of the gas to be measured from the second sub-passage B into the circuit chamber 135 is provided.
- the first introduction passage 161 has one end opened in the second sub-passage B and the other end opened in the circuit chamber 135 to communicate between the second sub-passage B and the circuit chamber 135.
- the first introduction passage 161 has an introduction port 162 that opens into the second sub-passage B.
- the introduction port 162 is arranged at a position offset outward from the side wall surface of the second sub-passage B.
- the introduction port 162 of the second sub-passage B is a folded-back portion that folds back from the outward passage portion B1 of the second sub-passage B to the return passage portion B2. Is also arranged at a curved portion located on the return passage portion B2 side.
- the first introduction passage 161 advances from the introduction port 162 toward the base end side of the measurement unit 113 along the Z-axis direction of the measurement unit 113, and is bent in a substantially L shape toward the side surface 123 of the measurement unit 113. It travels along the X-axis direction and has a shape continuous with the opening 163 that opens into the circuit chamber 135.
- a flow rate sensor (flow rate detection unit) 411 is arranged at an intermediate position of the outward passage portion B1 of the second sub-passage B.
- the introduction port 162 is provided at a position downstream of the flow rate sensor 411 in the measured gas flow direction of the second sub-passage B.
- the flow rate sensor 411 is provided in the sensor assembly 400, and the sensor assembly 400 is mounted on the circuit board 300.
- circuit components such as a sensor assembly 400, a pressure sensor 320, an intake air temperature sensor 321 and a humidity sensor 322 are mounted on the mounting surface on the front side, and chip resistance and chips are mounted on the mounting surface on the back side. Circuit parts (not shown) such as capacitors are provided.
- the longitudinal direction of the circuit board 300 extends from the base end portion to the tip end portion of the measurement unit 113, and the lateral direction of the circuit board 300 extends from the side surface 123 to the side surface 124 of the measurement unit 113. It is arranged in the measuring unit 113 so as to exist.
- the circuit board 300 has a substrate main body 301 arranged in the circuit chamber 135, and has a first protruding portion 302 arranged in the temperature detection passage 136 and a second protruding portion 303 arranged in the humidity measurement chamber 137. And the third protruding portion 304 arranged in the outward passage portion B1 of the second sub-passage B are provided so as to extend flush with each other from the substrate main body 301.
- An intake air temperature sensor 321 is mounted on the tip of the first protrusion 302, and a humidity sensor 322 is mounted on the second protrusion 303.
- the third protruding portion 304 is arranged to face the sensor assembly 400 in the outward passage portion B1 of the second sub-passage B.
- the third protruding portion 304 of the circuit board 300 closes the open portion of the concave groove 404 of the sensor assembly 400 to form the first passage portion D1. Further, the third protruding portion 304 of the circuit board 300 forms the second passage portion D2 with the bottom wall surface 152a of the second sub-passage groove 152.
- the base end portion of the support 401 is fixed to the circuit board 300 in the circuit chamber 135, the tip end portion is arranged so as to project to the second sub-passage groove 152, and the flow rate sensor 411 is provided at the tip end portion.
- the flow rate sensor 411 is supported by the sensor assembly 400 so as to be exposed to the outward passage portion B1 of the second sub-passage B.
- the flow rate sensor 411 is arranged so as to face the circuit board 300 protruding from the circuit chamber 135 with a predetermined distance, and measures the flow rate of the gas to be measured passing through the second sub-passage B.
- FIG. 7 is an enlarged view of the sensor assembly 400 shown in FIG.
- the sensor assembly 400 has a resin package structure in which the flow rate sensor 411, the LSI 412, and the lead frame 413 are molded with resin.
- the flow rate sensor 411 and the LSI 412 are mounted on one surface of the lead frame 413.
- the sensor assembly 400 is formed by sealing the flow rate sensor 411 with a resin so that the diaphragm of the flow rate sensor 411 is exposed.
- the sensor assembly 400 has a flat plate-shaped support 401 formed of a mold resin and having a predetermined plate thickness.
- the base end portion 401A of the support body 401 is arranged in the circuit chamber 135, and the tip end portion 401B of the support body 401 is arranged so as to project into the second sub-passage groove 152.
- the sensor assembly 400 is electrically connected to and mechanically fixed to the circuit board 300 by a fixing portion.
- a concave groove 404 is formed at the tip of the support 401.
- the concave groove 404 is formed so as to extend in the width direction of the tip of the support 401 at the tip of the support 401, and the flow rate sensor 411 is exposed at an intermediate position in the extending direction. Have been placed.
- the flow rate sensor 411 has a sensor element 405 having a diaphragm structure.
- the sensor element 405 of the flow rate sensor 411 has a diaphragm in which the diaphragm surface 411a is exposed in the outward passage portion B1 of the second sub-passage B, and the diaphragm back surface 411b is exposed in the closed chamber 421 isolated from the sub-passage 134. ..
- a heater portion is arranged on the diaphragm surface 411a, and a pair of electric resistance portions are arranged at positions separated from each other with the heater portion interposed therebetween.
- the air passing through the diaphragm surface 411a is heated by the heater unit, the heat distribution changes according to the air flow, and the flow rate of the gas to be measured is based on the change in electrical resistance according to the change in the heat distribution. To measure.
- the closed chamber 421 is provided in the sensor element 405 of the flow rate sensor 411.
- the sensor element 405 is mounted on one side of the lead frame 413, and the closing chamber 421 is closed by the polyimide tape 414 attached to the other side of the lead frame 413, and has a closed space isolated from the outside. is doing.
- the sensor assembly 400 is provided with a ventilation passage 422 in which one end is opened in the circuit chamber 135 and the other end is opened in the closed chamber 421 to communicate between the circuit chamber 135 and the closed chamber 421.
- a continuous concave groove is formed between the opening hole 423 and the closing chamber 421.
- a sheet-shaped polyimide tape 414 is attached to the other surface of the lead frame 413 so as to close the open portion of the concave groove, one end of which is open to the closed chamber 421 and the other end of which is continuous ventilation to the opening hole 423.
- a passage 422 is formed.
- the ventilation passage 422 communicates between the closed chamber 421 where the back surface of the diaphragm 411b is exposed and the circuit chamber 135.
- the ventilation passage 422 constitutes a second introduction passage capable of introducing the pressure of the gas to be measured from the circuit chamber 135 to the closed chamber 421.
- FIG. 8 is an enlarged view of a main part of FIG. 5
- FIG. 9 is a sectional view taken along line VIII-VIII of FIG. 5
- FIG. 10 is an enlarged view of a main part of FIG.
- the circuit chamber 135 is provided with at least one protrusion 210 at a position facing the opening 163 of the first introduction passage 161.
- the protrusion 210 is formed by a plurality of uneven shapes.
- the protrusion 210 is integrally formed with the cover 200.
- the protrusion 210 is provided between the side wall of the circuit chamber 135 and the circuit board 300 so that the gas to be measured can move between the second sub-passage B and the circuit chamber 135 through the first introduction passage 161.
- a predetermined gap is formed between the two.
- the protrusion 210 has a first protrusion 211 and a second protrusion 212, for example, as shown in FIGS. 4 and 9.
- the first protrusion 211 is arranged in the circuit chamber 135 at a position facing the opening 163 of the first introduction passage 161, and the second protrusion 212 is placed in the first introduction passage with the first protrusion 211 in between. It is arranged at a position away from the opening 163 of 161.
- the first protrusion 211 has a rectangular parallelepiped shape having a length W1 substantially the same as the opening width W0 of the opening 163, and is arranged so as to face each other over the entire width of the opening width W0 of the opening 163.
- the second protrusion 212 has a rectangular parallelepiped shape having a length W2 longer than the opening width W0 of the opening 163, and is arranged side by side in parallel with the first protrusion 211.
- the protrusion 210 forms a space S1 between the tip of the first protrusion 211 and the substrate main body 301 of the circuit board 300, and is between the first protrusion 211 and the second protrusion 212.
- a space S2 is formed in the space S2
- a space S3 is formed between the tip of the second protrusion 212 and the substrate main body 301 of the circuit board 300.
- the space S1 on the side closer to the opening 163 of the first introduction passage 161 is narrower (the cross-sectional area is smaller), and the space S2 on the side farther from the opening 163 of the first introduction passage 161.
- the space S2 and the space S3 are narrower in the space S3 than in the space S2.
- FIG. 11A and 11B are views for explaining the difference between the invention and the comparative example
- FIG. 11 (1) shows the structure of the comparative example having no protrusion 210
- FIG. 11 (2) shows the protrusion.
- the structure of the product of the present invention having 210 is shown
- FIG. 11 (3) is a graph showing the relationship between the sound pressure and the distance to the measurement point when there is a protrusion and when there is no protrusion.
- the turbocharger 15 is arranged downstream, and the sound wave generated by the turbocharger passes from the second sub-passage B through the first introduction passage 161 and enters the circuit chamber 135.
- the sound wave SW that has entered the circuit chamber 135 through the opening 163 of the first introduction passage 161 has no obstacle, so that the sound pressure is hardly attenuated. It proceeds to the depth of the circuit chamber 135, passes through the ventilation passage 422 from the opening hole 423 of the sensor assembly 400, and reaches the closed chamber 421 where the back surface of the diaphragm is exposed. Therefore, resonance of sound pressure occurs between the element front surface side and the element back surface side of the diaphragm, and the temperature distribution of the heater portion of the diaphragm may change due to thermal convection due to a thermoacoustic phenomenon, which may cause a flow rate detection error.
- the sound wave SW that has entered the circuit chamber 135 through the opening 163 of the first introduction passage 161 may be blocked by the protrusion 210 and proceed straight.
- the sound pressure of the sound wave SW is diffracted and attenuated and becomes smaller.
- the sound pressure is smaller than when there is no protrusion.
- the sound wave SW that entered the circuit chamber 135 from the opening 163 of the first introduction passage 161 proceeded from the space S1 to the space S2, and when the cross-sectional area became large, the speed and pressure decreased due to the expansion of the fluid and became smaller. Only energy passes through space S3 and the remaining energy is attenuated by reflection in space S2. Since the sound wave is reflected at the place where the impedance suddenly changes (rapid expansion / contraction), it is reflected at the entrance between the space S2 and the space S1 and at the exit between the space S2 and the space S3. Due to this reflection, sound wave interference occurs in the spaces S1, S2, and S3, the energy of the sound wave is consumed, and the sound pressure becomes small.
- the sound pressure in the second sub-passage B can be positively attenuated, and the sound wave can be suppressed from being transmitted to the closed chamber 421 while having a large energy. Therefore, it is possible to prevent the occurrence of sound pressure resonance on the element front surface side and the element back surface side of the diaphragm, and to improve the flow rate detection accuracy.
- FIG. 12 is a diagram showing sound pressure measurement results of the product of the present invention and a comparative example.
- the maximum sound pressure level difference near a predetermined frequency is 28 [dB] in the comparative example, whereas the maximum sound pressure is 25 [dB] in the product of the present invention, and the product of the present invention is compared. It can be understood that the sound pressure is reduced and improved compared to the example.
- FIG. 13 is a diagram showing a modified example of the present embodiment corresponding to FIG.
- the protrusion 210 has a plurality of third protrusions 213.
- Each of the plurality of third protrusions 213 has a rod shape, and is arranged in the circuit chamber 135 at a position facing the opening 163 of the first introduction passage 161.
- the plurality of third protrusions 213 are arranged so as to spread in a staggered manner at predetermined intervals from each other over a length substantially the same as the opening width W0 of the opening 163.
- the plurality of third protrusions 213 are arranged at intervals so as to block the sound wave SW that has entered the circuit chamber 135 from the opening 163 of the first introduction passage 161 so that the sound wave SW cannot proceed straight.
- the sound pressure in the second sub-passage B can be positively attenuated as in the above-described embodiment, and the sound wave is transmitted to the closed chamber 421 while having a large energy. It can be suppressed. Therefore, it is possible to prevent the occurrence of sound pressure resonance on the element front surface side and the element back surface side of the diaphragm, and to improve the flow rate detection accuracy. Further, the amount of sound pressure attenuation can be arbitrarily adjusted by changing the number of the third protrusions 213.
- the present invention is not limited to the above-described embodiments, and various designs are designed without departing from the spirit of the present invention described in the claims. You can make changes.
- the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations.
- it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment and it is also possible to add the configuration of another embodiment to the configuration of one embodiment.
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Abstract
Description
主通路を流れる被計測気体の物理量を検出する物理量検出装置であって、
前記主通路に配置される筐体と、該筐体に形成された副通路と、該副通路に配置される流量検出部と、該流量検出部に電気的に接続された回路部と、前記筺体に形成されて前記回路部を収容する回路室と、前記副通路に一端が開口し他端が前記回路室に開口して前記副通路と前記回路室との間を連通し、前記副通路から前記回路室に前記被計測気体の圧力を導入可能な第1圧力導入通路と、を備え、
前記流量検出部は、前記副通路にダイアフラム表面が露出し、前記副通路から隔絶された閉塞室にダイアフラム裏面が露出するダイアフラムと、前記回路室に一端が開口し、前記閉塞室に他端が開口して前記回路室と前記閉塞室との間を連通し、前記回路室から前記閉塞室に前記被計測気体の圧力を導入可能な第2圧力導入通路とを有し、
前記回路室は、前記第1圧力導入通路の他端が開口する開口部に対向する位置に設けられた少なくとも一つ以上の突起部とを有することを特徴とする。
図1は、電子燃料噴射方式の内燃機関システム1に、本発明に係る物理量検出装置を使用した一実施例を示す、システム図である。
本実施形態の物理量検出装置は、自動車用の内燃機関システム1に用いられる。内燃機関システム1は、ターボチャージャ15付きのエンジン2を有しており、主通路22には、上流側から順番に、エアクリーナ4、物理量検出装置20、インタークーラ6、スロットルバルブ7、吸気管8が設けられ、排気通路9には排気触媒10が設けられている。そして、吸気管8には、熱式湿度測定装置11と、吸気圧力センサ12と、吸気温度センサ13が取り付けられており、エンジン2に吸入される吸入空気の湿度、圧力、温度を測定する。
物理量検出装置20は、主通路22の通路壁に設けられた取り付け孔から主通路22の内部に挿入して主通路22に固定された状態で使用される。物理量検出装置20は、被計測気体が流れる主通路22に配置される筐体を備えている。物理量検出装置20の筐体は、ハウジング100と、ハウジング100に取り付けられるカバー200を有している。ハウジング100は、例えば合成樹脂製材料を射出成形することによって形成されている。そして、カバー200は、例えば金属材料や合成樹脂材料からなる板状部材によって構成されており、本実施例では、アルミニウム合金あるいは合成樹脂材料の射出成形品によって構成されている。
センサアセンブリ400は、流量センサ411とLSI412とリードフレーム413を樹脂でモールドした樹脂パッケージの構造を有している。流量センサ411とLSI412は、リードフレーム413の一方面に実装されている。センサアセンブリ400は、流量センサ411のダイアフラムが露出するように流量センサ411を樹脂で封止することによって形成されている。
所定周波数付近の音圧レベル差が、比較例では最大音圧28[dB]であるのに対し、本発明品では最大音圧が25[dB]となっており、本発明品の方が比較例よりも音圧が減されて、改善されていることが理解できる。
変形例では、突起部210は、複数の第3突起部213を有している。複数の第3突起部213は、それぞれが棒形状を有しており、回路室135内において第1導入通路161の開口部163と対向する位置に配置されている。複数の第3突起部213は、開口部163の開口幅W0とほぼ同じ長さに亘って、互いに所定の間隔をおいて千鳥状に広がるように配置されている。複数の第3突起部213は、第1導入通路161の開口部163から回路室135に侵入した音波SWが真っ直ぐに進むことができないように遮る程度の間隔を有して配置されている。
Claims (9)
- 主通路を流れる被計測気体の物理量を検出する物理量検出装置であって、
前記主通路に配置される筐体と、該筐体に形成された副通路と、該副通路に配置される流量検出部と、該流量検出部に電気的に接続された回路部と、前記筐体に形成されて前記回路部を収容する回路室と、前記副通路に一端が開口し他端が前記回路室に開口して前記副通路と前記回路室との間を連通し、前記副通路から前記回路室に前記被計測気体の圧力を導入可能な第1導入通路と、を備え、
前記流量検出部は、前記副通路にダイアフラム表面が露出し、前記副通路から隔絶された閉塞室にダイアフラム裏面が露出するダイアフラムと、前記回路室に一端が開口し、前記閉塞室に他端が開口して前記回路室と前記閉塞室との間を連通し、前記回路室から前記閉塞室に前記被計測気体の圧力を導入可能な第2導入通路とを有し、
前記回路室は、前記第1導入通路の他端が開口する開口部に対向する位置に少なくとも一つ以上の突起部が設けられていることを特徴とする物理量検出装置。 - 前記突起部は、前記開口部と対向する位置に配置される第1突起部と、該第1突起部を間に介して前記開口部から離間する位置に配置される第2突起部とを有していることを特徴とする請求項1に記載の物理量検出装置。
- 前記第1突起部は、前記開口部の開口幅と同じ長さを有し、前記開口部の開口幅の全幅に亘って対向して配置され、
前記第2突起部は、前記開口部の開口幅よりも長い長さを有しており、前記第1突起部と平行に並んで配置されていることを特徴とする請求項2に記載の物理量検出装置。 - 前記突起部は、それぞれが棒形状を有した複数の第3突起部を有していることを特徴とする請求項1に記載の物理量検出装置。
- 前記複数の第3突起部は、前記開口部の開口幅と同じ長さに亘って、互いに所定の間隔をおいて千鳥状に広がるように配置されていることを特徴とする請求項4に記載の物理量検出装置。
- 前記第1導入通路は、前記副通路の側壁面から外側にオフセットした位置に導入口が配置されていることを特徴とする請求項1に記載の物理量検出装置。
- 前記副通路は、所定の軸方向に沿って軸方向一方側に向かって延在する往通路部と、該往通路部の端部でUターンして軸方向他方側に向かって延在する復通路部とを有しており、
前記導入口は、前記副通路の前記往通路部から前記復通路部に折り返す折返し部において、半円弧状にカーブする外周側の側壁面でかつ前記折返し部の頂部よりも前記復通路部側に位置する曲がり部分に配置されていることを特徴とする請求項6に記載の物理量検出装置。 - 前記副通路には、前記被計測気体の流量を検出する前記流量検出部が配置されており、 前記導入口は、前記副通路の被計測気体流れ方向において前記流量検出部よりも下流側の位置に設けられていることを特徴とする請求項7に記載の物理量検出装置。
- 前記流量検出部は、前記副通路の前記往通路部に設けられていることを特徴とする請求項8に記載の物理量検出装置。
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DE112021004518.0T DE112021004518T5 (de) | 2020-11-20 | 2021-09-08 | Erfassungsvorrichtung für eine physikalische Größe |
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Citations (6)
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JP2012052975A (ja) * | 2010-09-03 | 2012-03-15 | Hitachi Automotive Systems Ltd | 熱式空気流量センサ |
JP2017181521A (ja) * | 2017-06-07 | 2017-10-05 | 株式会社デンソー | 流量センサ |
JP2020034508A (ja) * | 2018-08-31 | 2020-03-05 | 日立オートモティブシステムズ株式会社 | 物理量検出装置 |
US20200158546A1 (en) * | 2017-04-11 | 2020-05-21 | Robert Bosch Gmbh | Sensor for detecting at least one property of a fluid medium |
US20200263623A1 (en) * | 2017-09-20 | 2020-08-20 | Robert Bosch Gmbh | Method and device for controlling a heating element for heating a sensor element of a mass air-flow sensor for a vehicle and mass air-flow sensor system for a vehicle |
JP2021067510A (ja) * | 2019-10-21 | 2021-04-30 | 日立Astemo株式会社 | 物理量検出装置 |
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Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2012052975A (ja) * | 2010-09-03 | 2012-03-15 | Hitachi Automotive Systems Ltd | 熱式空気流量センサ |
US20200158546A1 (en) * | 2017-04-11 | 2020-05-21 | Robert Bosch Gmbh | Sensor for detecting at least one property of a fluid medium |
JP2017181521A (ja) * | 2017-06-07 | 2017-10-05 | 株式会社デンソー | 流量センサ |
US20200263623A1 (en) * | 2017-09-20 | 2020-08-20 | Robert Bosch Gmbh | Method and device for controlling a heating element for heating a sensor element of a mass air-flow sensor for a vehicle and mass air-flow sensor system for a vehicle |
JP2020034508A (ja) * | 2018-08-31 | 2020-03-05 | 日立オートモティブシステムズ株式会社 | 物理量検出装置 |
JP2021067510A (ja) * | 2019-10-21 | 2021-04-30 | 日立Astemo株式会社 | 物理量検出装置 |
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US20230408316A1 (en) | 2023-12-21 |
JP7407305B2 (ja) | 2023-12-28 |
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