WO2019073771A1

WO2019073771A1 - Humidity measuring device

Info

Publication number: WO2019073771A1
Application number: PCT/JP2018/034733
Authority: WO
Inventors: 丈夫細川; 洋小貫; 安藤　亮; 浩昭星加
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2017-10-10
Filing date: 2018-09-20
Publication date: 2019-04-18
Also published as: JP2021014987A

Abstract

According to the present invention, a humidity measuring device capable of performing highly accurate humidity measurement with less noise due to an air flow can be obtained. A humidity measuring device 1 according to the present invention is provided with: a humidity detection element 4; a measuring chamber 5, in which the humidity detection element 4 is disposed; an introduction pipe 3 for introducing air toward the measuring chamber 5; and a partitioning section 10, which partitions the introduction pipe 3 and the measuring chamber 5, and which is provided with a communication path for communicating the introduction pipe 3 and the measuring chamber 5 with each other.

Description

Humidity measuring device

The present invention relates to a detection device suitable for measuring the humidity of intake air in an internal combustion engine.

In a car, an electronically controlled fuel injection system is adopted, and various sensors and control devices are disposed in an engine room. One of the sensors disposed in the engine room is a humidity measuring device. This humidity measuring device is used for fuel control.

In addition to the flow rate, temperature, and pressure of the intake air, in an internal combustion engine for automobiles, etc., it is required to measure environmental conditions such as humidity with high accuracy. When measuring humidity by an engine, high responsiveness is required in addition to high detection accuracy.

As a background art of this technical field, a humidity measuring device described in JP-A-2015-232514 (Patent Document 1) is known. The humidity measuring device of Patent Document 1 includes a humidity sensor which is disposed in an intake passage through which intake air flows, and generates a signal according to the humidity of the intake air flowing through the intake passage. The intake channel has a throttle which reduces the cross-sectional area of the flow path, and the humidity sensor is arranged at this throttle. The humidity measuring device of Patent Document 1 increases the flow velocity of the intake air by disposing the humidity sensor at the aperture, suppresses the stagnation of the intake air in the vicinity of the humidity sensor, and improves the responsiveness of the humidity sensor. (See summary).

Further, Japanese Patent Application Laid-Open No. 2003-107033 (Patent Document 2) describes a gas sensor having a gas sensor element inserted and disposed in a housing. This gas sensor is fixed to the front end side of the housing, and has a measurement-side cover including a cylindrical outer cover and an inner cover having different diameters that share substantially the same central axis. The outer cover and the inner cover each have an outer introduction hole and an inner introduction hole for introducing the gas to be measured into the inner cover from the outside of the outer cover (see the abstract).

JP, 2015-232514, A JP, 2003-107033, A

The humidity measuring device of Patent Document 1 can improve responsiveness. However, since the flow velocity of the intake air near the humidity sensor is increased, the flow of air may affect the detection signal of the humidity sensor as noise. For this reason, there is a possibility that the noise generated by the flow of air may cause a limit in achieving high accuracy of the humidity measuring device.

Specifically, the gas sensor of Patent Document 2 is a sensor that detects an oxygen concentration, and the gas which has passed through the outer introduction hole and the inner introduction hole formed in the outer cover and the inner cover is a measurement gas in which the gas sensor element is disposed. It flows directly into the chamber. Therefore, when the humidity measuring device is configured with the structure of the gas sensor of Patent Document 2, the gas flowing into the measurement gas chamber flows with a relatively high flow velocity in the vicinity of the gas sensor element. For this reason, the flow of gas may affect as noise to the detection signal of the gas sensor element, and there may be a limit due to the noise generated by the flow of gas in achieving high accuracy of the gas sensor.

An object of the present invention is to provide a humidity measuring device capable of performing highly accurate measurement with less noise due to air flow.

In order to solve the above problems, for example, the configuration described in the claims is adopted.
In the humidity measuring device according to the present invention, the introduction pipe for taking in the intake air into the physical quantity detection section and the inlet section of the introduction pipe are the first wall surface and the second wall surface located inside the first wall. The first wall surface portion and the second wall surface portion are provided such that the window of the first wall surface portion and the wall of the second wall surface portion overlap in a direction perpendicular to the introduction direction of the introduction pipe. The second wall portion has a shape in which a wall and a window are alternately formed at a predetermined interval.

Thereby, even when measuring the humidity of the air flowing in the intake pipe, for example, in the intake system of the internal combustion engine, noise to the humidity signal due to the air flow is reduced, and a high speed response to the humidity change of the air flowing in the intake pipe is obtained. This can be realized regardless of the direction of the air flow or the mounting direction of the humidity measuring device.

According to the present invention, it is possible to obtain a humidity measuring device capable of performing highly accurate humidity measurement with less noise due to the flow of air. Problems, configurations, and effects other than those described above will be apparent from the description of the embodiments below.

It is the schematic which shows the lower surface of the humidity measuring device of one Example which concerns on this invention. It is the schematic which shows the AA cross section of FIG. 1A. It is the schematic which shows the cross section in the state which attached the humidity measuring device of one Example which concerns on this invention to the inlet pipe. It is a bottom view which shows the outline of the example of a change which changed the structure of the introduction guide 2 about the humidity measuring device of one Example which concerns on this invention.

Hereinafter, embodiments of the present invention will be described based on the drawings. Hereinafter, although the example which applied the humidity measuring device 1 which concerns on this invention to the intake system of an internal combustion engine is demonstrated, the application object of the humidity measuring device 1 is not necessarily limited to the intake system of an internal combustion engine.

Further, the vertical direction in the following description is defined on the basis of the vertical direction in FIG. 1B, and does not necessarily coincide with the vertical direction in the state where the humidity measuring device is mounted.

FIG. 1A is a schematic view showing the lower surface of the humidity measuring device according to one embodiment of the present invention. FIG. 1B is a schematic view showing an AA cross section of FIG. 1A.

As shown in FIGS. 1A and 1B, the humidity measuring device 1 according to the present embodiment includes a housing 1A, a humidity detecting element 4, a substrate 10, a measuring chamber 5, an introducing pipe 3, and

air introducing portions

8a and 8b. , The introduction guide 2, and the connection terminal 9.

The housing 1 </ b> A is a resin member having a measurement unit housing space 13. A substrate 10 on which the humidity detection element 4 is mounted and a sensor cover 6 covering the humidity detection element 4 are accommodated in the measurement unit accommodation space 13. A recess 6 a is formed in the sensor cover 6, and by combining the sensor cover 6 and the substrate 10, a measurement chamber 5 in which the humidity detection element 4 is accommodated in the recess 6 a is configured. That is, the humidity detection element 4 is disposed in the measurement chamber 5 constituted by the sensor cover 6 and the substrate 10.

Although the housing 1A is fixed to the pipe wall 11 of the intake pipe (see FIG. 2), the side fixed to the intake pipe wall 11 is called the proximal side or the fixed side, and from the proximal side to the inner side of the intake pipe 11. The side to be inserted into the formed air passage (air passage) is called the tip side. The measuring unit housing space 13, the measuring chamber 5, the humidity detecting element 4, the substrate 10, and the sensor cover 6 are configured at the end (proximal end) of the proximal end side of the housing 1A and disposed outside the intake pipe 11. Ru.

The connector portion 9 is integrally formed on the housing 1A with a resin that forms the main body of the housing 1A. In the inner space of the connector portion 9, a plurality of connection terminals 9 a project from the measurement portion accommodation space 13. That is, the connection terminal 9a is provided so as to protrude outward from the inner space (measurement portion accommodation space) 13 of the housing 1A. The connection terminal 9 a is electrically connected to the humidity detection element 4 via the substrate 10, and enables power supply to the humidity detection element 4 and extraction of a detection signal from the humidity detection element 4. Hereinafter, the power supply and the detection signal will be described as being called an electrical signal.

An introduction pipe (air introduction pipe) 3 is formed in the housing 1A so as to extend from the measurement portion accommodation space 13 toward an end (tip end) on the tip end side. A substrate 10 is provided at the end of the proximal end side of the introduction pipe 3, and the substrate 10 blocks most of the cross section of the air passage formed inside the introduction pipe 3. The substrate 10 is provided with air introduction portions (communication passages or communication holes) 8a and 8b, and the air passage of the introduction pipe 3 is in communication with the measurement chamber 5 through the

air introduction portions

8a and 8b. That is, the introduction pipe 3 and the

air introduction parts

8 a and 8 b constitute an introduction part (air introduction part) for introducing air into the measurement chamber 5.

In the present embodiment, the housing 1A is constituted by two members of a proximal end housing member (first housing member) 1Aa and a distal end housing member (second housing member) 1Ab. The proximal end side member 1Aa is provided with a measurement unit housing space 13, a measurement chamber 5, a humidity detection element 4, a substrate 10, a sensor cover 6, and a part of the proximal end side of the introduction pipe 3. The leading end side member 1Ab is provided with a part of the leading end side of the introducing pipe 3 and an introducing guide (air introducing guide) 2 formed at the leading end of the introducing pipe 3.

The introduction guide 2 protrudes from the inlet opening 3a of the introduction pipe 3 to the tip end side and guides the measurement medium with a plurality of first introduction guides (first wall surface portions) 2a and a plurality of second introduction guides (second wall surfaces) Part) 2b. The plurality of second introduction guides 2 b are disposed on the tip end side with respect to the inlet opening 3 a of the introduction pipe 3 and on the radially outer side of the inlet opening 3 a. The plurality of first introduction guides 2a are disposed on the tip end side with respect to the inlet opening 3a of the introduction tube 3 and radially outside the plurality of second introduction guides 2b. The plurality of first introduction guides 2a are arranged radially outward with respect to the plurality of second introduction guides 2b, and the plurality of second introduction guides 2b are arranged radially inward with respect to the plurality of first introduction guides 2a. Will be placed.

Each of the plurality of second introduction guide portions 2b is arranged to be separated in the circumferential direction surrounding the inlet opening 3a, and a second circumferential gap (a second window) is formed between two adjacent second introduction guide portions 2b. Part 2d is formed. Each of the plurality of first introduction guide portions 2a is arranged to be separated in the circumferential direction surrounding the inlet opening 3a and the second introduction guide portion 2b, and between the adjacent two first introduction guide portions 2a, the first A circumferential gap (first window) 2c is formed. Further, the plurality of first introduction guide portions 2a and the plurality of second introduction guide portions 2b are spaced apart in the radial direction, and between the plurality of first introduction guide portions 2a and the plurality of second introduction guide portions 2b The radial gap 2e is formed on the Thus, the introduction guide 2 has a first introduction guide 2a, a second introduction guide 2b, a first window 2c, a second window 2d, and a radial gap 2e. Thus, in the introduction guide 2, a passage (flow path) in which air flows from the outer peripheral side of the introduction guide 2 to the inner peripheral side of the introduction guide 2 through the first window 2 c and the second window 2 d is configured. .

In the present embodiment, the housing 1A is constituted by two members, but may be constituted by one member or may be divided into three or more members. Since the housing 1A is configured by two members, the part configured by the proximal end housing member 1Aa is made common, and a plurality of types in which the configuration of the part of the introduction guide 2 is changed is configured with a reduced number of parts. Can. Alternatively, the design change of the portion of the introduction guide 2 is facilitated.

Further, a part of the leading end side housing member 1Ab on the opposite side to the leading end side (the measurement unit accommodation space 13 side) of the introduction pipe 3 and the introduction guide 2 are formed, whereby a plurality of first introduction guide portions 2a And the plurality of second introduction guide portions 2b can be integrally formed parts.

Next, a mechanism for introducing the air flowing through the intake pipe 11 into the measurement chamber of the humidity measuring device 1 will be described.

FIG. 2 is a schematic view showing a cross section of the humidity measuring device according to one embodiment of the present invention in a state of being attached to an intake pipe.

The first window portion 2c and the second window portion 2d are arranged so as not to align in a straight line in the radial direction. That is, the first introduction guide portion (first wall surface portion) 2a includes a first window portion 2c and a second introduction guide portion (second wall surface portion) 2b configured between two adjacent first introduction guide portions 2a. And so as to overlap in the circumferential direction of the inlet opening 3a. Further, in the second introduction guide portion 2b, the second window portion 2d configured between the two adjacent second introduction guide portions 2b and the first introduction guide portion 2a overlap in the circumferential direction of the entrance opening portion 3a. Provided as.

Thereby, the introduction guide 2 prevents air from flowing straight from the outer peripheral side to the inner peripheral side. Thus, the first introduction guide portion 2a and the second introduction guide portion 2b of the introduction guide 2 form a labyrinth portion 7a in which the air passage bends in a complicated manner.

In FIG. 2, Q1 and Q2 indicate the flow of air.

The air having passed through the labyrinth portion 7a flows into the introduction pipe 3 from the inlet opening 3a as a swirling flow. The air flowing into the introduction pipe 3 flows by swirling so that the flow toward the substrate 10 (base end) and the flow from the substrate 10 toward the inlet opening 3 a (tip) are mixed. For this reason, the portion of the introduction pipe 3 constitutes a gas exchange unit 7b. In the gas exchange unit 7b, the air is smoothly exchanged, and the air in the vicinity of the substrate 10 is smoothly exchanged.

In the present embodiment, the air flowing into the introduction pipe 3 flows out of the inlet opening 3 a to the outside of the introduction pipe 3. Thus, the inlet opening 3 a constitutes the outlet (outlet opening) of the introduction pipe 3.

The introduction pipe 3 and the measurement chamber 5 are separated by the substrate 10, and the measurement chamber 5 is configured to have a diffusion portion 7c. That is, the air flow flowing through the introduction pipe 3 and reaching the substrate 10 is blocked by the substrate 10, and the air on the introduction pipe 3 side reaching the vicinity of the substrate 10 is introduced into the measurement chamber 5 by diffusion through the

air introduction portions

8a and 8b. Ru.

That is, the substrate 10 constitutes a blocking portion (a blocking wall) that blocks the flow of air flowing through the introduction pipe 3. Alternatively, the substrate 10 constitutes a partition (partition wall) that partitions the introduction pipe 3 and the measurement chamber 5. The substrate 10 has air introducing portions (communication paths) 8 a and 8 b formed in part of the surface facing the inner side of the introducing pipe 3 in order to stop the air flow.

In the diffusion, air is introduced into the measurement chamber 5 by utilizing the phenomenon that the gas spreads in the space due to the concentration difference of the gas (the humidity difference of the air in the present embodiment).

In the humidity measuring device 1 of the present embodiment, gas exchange in the vicinity of the humidity detecting element 4 is performed by diffusion from the

air introducing portions

8a and 8b, and high precision humidity measurement with less noise to the humidity signal due to the flow of air is realized. ing.

In the present embodiment, as the humidity detection element 4, an example of a thermal humidity detection element that detects humidity by measuring the change in heat conduction of the measurement medium based on the amount of heat released from the heating element exposed to the measurement medium However, a capacitive humidity detection element may be used.

As described above, the introduction guide 2 is disposed on the upstream side of the introduction pipe 3 and is configured to actively exchange air from the inlet opening 3 a to the substrate 10 that divides the introduction pipe 3 and the measurement chamber 5. There is. In the introduction guide 2, the first introduction guide 2a, the second introduction guide 2b, the first window 2c, and the second window 2d are uniformly distributed in the circumferential direction of the inlet opening 3a of the introduction tube 3 The inlet opening 3a of the introduction pipe 3 is opened inside the introduction guide 2 from any direction perpendicular to the air introduction direction.

According to this configuration, the air that has hit the introduction guide 2 is introduced into the introduction pipe 3 over the entire circumference (360 °) in the circumferential direction of the inlet opening 3a. Therefore, air can be introduced to the humidity sensor element 4 regardless of the direction of the air flow, and high-speed response can be ensured to the humidity change of the measurement target medium.

FIG. 3 is a bottom view schematically showing a modified example in which the configuration of the introduction guide 2 is changed in the humidity measuring device according to the embodiment of the present invention.

In this modified example, the introduction guide 2 has a wing-shaped portion 2 f in place of the first introduction guide portion 2 a and the second introduction guide portion 2 b. The other configuration is the same as the above-described embodiment.

A plurality of wing-shaped portions 2 f are arranged at intervals in the circumferential direction on the radially outer side of the inlet opening 3 a of the introduction pipe 3. A circumferential gap (window) 2g is formed between two adjacent wing-shaped portions 2f. The wing-shaped portion 2f has a curved shape on the plane of FIG. 3 (on a plane perpendicular to the air introduction direction of the introduction pipe 3), and constitutes a curved flow path 2g. The wing-shaped portion 2 f, that is, the curved flow path 2 g applies a turning force to the air flow flowing into the introduction pipe 3.

In particular, in the present embodiment, air is introduced into the introduction pipe 3 from the entire circumference of the inlet opening 3a in the same manner as the above-described embodiment by evenly distributing the wing-shaped portions 2f all around the inlet opening 3a. be able to.

Also in this modification, since the air can be introduced into the introduction pipe 3 while swirling, the same effect as that of the above-described embodiment can be obtained.

The first introduction guide portion 2a, the second introduction guide portion 2b, and the wing shaped portion 2f are disposed radially outside the inlet opening 3a of the introduction tube 3, and from the tip end portion (inlet opening 3a) of the introduction tube 3 It is comprised by the projecting part formed so that the side (proximal end side) in which the measurement chamber 5 was provided may project on the opposite side (distal end side).

In the engine room of automobiles in recent years, restrictions on the mounting layout have been increased due to the increase in the number of mounted parts along with the downsizing and the sophistication. For this reason, it is desirable for the humidity measuring device to be a humidity measuring device that is mounted in a free direction with less restrictions on the mounting direction. In the present embodiment, since the inflow direction of the air to the introduction pipe 3 for introducing the air into the measurement chamber 5 is not limited, the mounting direction of the humidity measuring device 1 is not limited. That is, the mounting direction of the humidity measuring device does not depend on the air flow direction. Therefore, the humidity measuring device of the present embodiment has few restrictions on the mounting direction and is suitable for being disposed in the engine room of a car.

The present invention is not limited to the embodiments described above, but includes various modifications. For example, the embodiments described above are described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations. In addition, with respect to a part of the configuration of the embodiment, it is possible to add, delete or replace other configurations.

DESCRIPTION OF SYMBOLS 1 ... Humidity measurement apparatus, 1A ... Housing, 1Aa ... Base end side housing member (1st housing member), 1Ab ... Tip side housing member (2nd housing member), 2 ... Introduction guide, 2a ... 1st introduction guide part ( First wall portion), 2b second introduction guide portion (second wall portion) 2c first window portion (first circumferential gap) 2d second window portion (second circumferential gap) 2e Radial clearance, 2f ... wing shape portion, 3 ... introduction pipe, 3a ... inlet opening, 4 ... humidity detection element, 5 ... measurement chamber, 6 ... sensor cover, 6a ... recess, 7a ... labyrinth portion, 7b ... gas exchange Portion 7c: Diffusion portion 8a: Air introduction portion 8b: Air introduction portion 9a: Connection terminal 10: Substrate 11: Intake pipe wall 12: Intake pipe 13: Measurement portion accommodation space Q1: Air flow , Q2 ... air flow.

Claims

A humidity detection element,
A measurement chamber in which the humidity detection element is disposed;
An introduction pipe for introducing air toward the measurement chamber;
A partition part in which a communication passage for connecting the introduction pipe and the measurement chamber is provided at a part while separating the introduction pipe and the measurement chamber;
Humidity measuring device equipped with.
In the humidity measuring device according to claim 1,
An air introduction guide disposed radially outside the inlet opening of the introduction tube;
The humidity measuring device having a plurality of projecting portions distributed around the entire circumference of the inlet opening so that the introduction guide protrudes from the inlet opening to the side opposite to the side where the measurement chamber is provided. .
In the humidity measuring device according to claim 2,
The introduction guide is disposed, as the protruding portion, at a plurality of first wall surface portions distributed around the entire circumference of the inlet opening, and at a position spaced radially inward with respect to the first wall surface portion And a plurality of second wall portions distributed around the entire circumference of the inlet opening,
The first wall surface portion is provided such that a first window portion configured between two adjacent first wall surface portions and the second wall surface portion overlap in a circumferential direction of the inlet opening.
The humidity measurement in which the second wall portion is provided such that a second window portion configured between two adjacent second wall portions and the first wall portion overlap in the circumferential direction of the inlet opening. apparatus.
In the humidity measuring device according to claim 3,
The humidity measuring device, wherein the introduction pipe has a predetermined length and constitutes a gas exchange area.
In the humidity measuring device according to claim 4,
The measuring chamber constitutes a diffusion area,
The humidity measuring device, wherein the gas exchange area is configured between the diffusion area and the introduction guide.
In the humidity measuring device according to claim 5,
A housing having a measurement unit accommodation space and the introduction pipe;
A substrate on which the humidity detection element is mounted, and a sensor cover that constitutes the measurement chamber together with the substrate are accommodated in the measurement unit accommodation space,
The humidity measuring device which comprises the said partition part by the said board | substrate.
In the humidity measuring device according to claim 6,
The housing is a first housing member in which the measurement unit accommodation space and a part of the introduction tube on the side of the measurement unit accommodation space are formed, and the side opposite to the measurement unit accommodation space of the introduction tube And a second housing member in which a portion of the second housing member and the introduction guide are formed.