WO2014002735A1

WO2014002735A1 - Air quantity detection device

Info

Publication number: WO2014002735A1
Application number: PCT/JP2013/065911
Authority: WO
Inventors: 斉藤　孝行; 半沢　恵二; 余語　孝之
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2012-06-29
Filing date: 2013-06-10
Publication date: 2014-01-03
Also published as: JP5675717B2; JP2014010026A

Abstract

It is an object of the present invention to provide an air quantity detection device having high contamination resistance and good humidity measurement accuracy. In order to achieve this object, the air quantity detection device of the present invention includes: a mounting portion for an intake pipe; a housing member having an integrated connector and connector terminal member; a first bypass channel for taking in some of the fluid flowing through the intake pipe; a flow rate detecting element provided inside the first bypass channel; a second bypass channel separate from the first bypass channel; and a humidity detecting element provided inside the second bypass channel. The second detecting element is mounted in a position to the outside of the inner wall of the intake pipe; and the inlet to the second bypass channel is provided on a side wall of the housing member on the forward flow side.

Description

Air physical quantity detector

The present invention relates to an air physical quantity detection device related to intake air of an internal combustion engine.

As a physical quantity detection technology for intake air of an internal combustion engine, there is a multifunctional air flow measurement device that integrates an air flow measurement device and a humidity detection device. Normally, the intake air of an automobile is taken in after airborne substances are removed by an air filter element provided in the air cleaner box. However, because a large pressure loss created by the air filter element that causes engine output reduction and fuel consumption deterioration is not desired, filter paper that captures fine carbon contained in the exhaust gas, for example, is not used. These fine airborne substances pass through the filter paper and are sucked into the engine. In addition, after the engine stops, engine oil that has been exposed to high temperatures may become steam and flow back to the air cleaner box. For the above reasons, the air downstream of the air cleaner box is not always clean. . Patent Document 1 is provided with a second sub air passage that opens inside the sub air passage in which the air flow rate detecting element is mounted for the purpose of providing clean intake air to the integrated humidity detecting element. , It is disclosed that a humidity detection element is mounted in the second sub air passage, and a portion of the second sub passage where the humidity detection element is mounted is located outside the outer wall of the intake pipe component member. .

JP2010-043883

In recent years, electronic control of diesel engines has been advanced, and the pollution environment of diesel engines is even more severe than gasoline engine systems. Also in a gasoline engine, in order to further improve flow rate detection accuracy, it is desired to suppress a measurement error of a humidity detection element due to a contaminated material. With the demand for expanding the application of humidity detection devices to internal combustion engines and improving the reliability of humidity detection devices, it is necessary to improve the fouling resistance required for humidity detection devices. Further, in order to further reduce fuel consumption, it is necessary to improve responsiveness in order to reduce measurement errors of the humidity detection device.

In Patent Document 1, by increasing the distance from the sub air passage to the humidity detection element, it becomes difficult for a pollutant or a water droplet to reach the humidity detection element, and the fouling resistance is improved. However, since the distance from the sub air passage to the humidity detecting element is increased, the air does not easily flow into the humidity detecting element, and it is difficult to ensure the air flow rate inside the second sub air passage. For this reason, Patent Document 1 has room for study on improving the responsiveness of the humidity detection element.

An object of the present invention is to provide an air physical quantity detection device having high antifouling property and good humidity measurement accuracy.

In order to solve the above problems, an air physical quantity detection device of the present invention includes a housing member integrally including an attachment portion to the intake pipe, a connector and a connector terminal member, and a part of fluid flowing in the intake pipe. A first bypass passage for taking in water, a flow rate detecting element provided in the first bypass passage, a second bypass passage provided separately from the first bypass passage, and provided in the second bypass passage. A humidity detection element, wherein the second detection element is mounted on a portion that is located outside the inner wall surface of the intake pipe, and the inlet opening of the second bypass passage is on the forward flow side of the housing member It is provided in the side wall surface of this.

According to the present invention, it is possible to provide an air physical quantity detection device having high antifouling property and good humidity measurement accuracy.

(A) Front structural view showing the first embodiment of the present invention, (b) AA sectional view of (a) Sectional drawing which shows 1st Example of this invention (A) Front structural view showing the second embodiment of the present invention, (b) BB sectional view of (a) Sectional drawing which shows the modification of 2nd Example of this invention (A) Front structural view showing a third embodiment of the present invention, (b) CC cross-sectional view of (a) Front structural view showing a fourth embodiment of the present invention. Sectional drawing which shows 5th Example of this invention Sectional drawing which shows 6th Example of this invention An embodiment in which the present invention is applied to an internal combustion engine of an electronic fuel injection system

A first embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, a sensor mounting hole 3 is provided in a part of the intake pipe 2 constituting the main passage 1, and an air physical quantity detection device 5 is attached via a seal member 4. This air physical quantity detection device 5 is a device in which a humidity sensor 8 part and an air flow rate sensor 9 part are integrally assembled using a housing member 7 integrally molded with a connector 6 as a basic structure.

The air flow rate sensor 9 is provided with a first bypass passage 10 for taking in part of the intake air flowing through the main passage 1, and the first bypass passage 10 includes a part of the housing member 7, a base member 11, Furthermore, it is formed using the first bypass component 12, and inside the first bypass passage 10, an air flow sensor element 13 for detecting the air flow rate, a temperature compensation element 14 for detecting the air flow rate, and a temperature sensor 15 are provided. Is implemented. These elements are connected to the air flow sensor electronic circuit board 18 via the terminal member 16 and the metal wire 17, and the air flow sensor electronic circuit board 18 and the air flow sensor connector terminal 19 are electrically connected by the metal wire 17. By connecting to, input / output via the connector 6 becomes possible.

In the humidity sensor 8, a humidity sensor electronic circuit board 21 having a humidity sensor element 20 is mounted on the housing member 7, and the humidity sensor electronic circuit board 21 and the humidity sensor connector terminal 22 are electrically connected by a metal wire 17. After the connection, the coating member 23 is used to protect the surface of the humidity sensor electronic circuit board 21, and external input / output is performed through the same connector 6 as the air flow sensor 9. The housing member 7 is also configured with a second bypass passage 24 that houses the humidity sensor element 20, and is completely separated and independent from the first bypass passage 10.

When the air flow sensor element 13 is prevented from being polluted, a bent portion is formed in the first bypass passage 10 to centrifuge the pollutant and water droplets taken in with the air. However, when the inlet 24 of the second bypass passage is opened in the first bypass passage 10 having a bent portion, depending on the position where the inlet 24 of the second bypass passage is provided, the centrifugally contaminated pollutant may be in the second auxiliary air passage. Since it is sprayed directly to the entrance, the contaminated material flows into the second sub-passage 24, and the humidity detecting element may be easily contaminated.

According to the above configuration, since the second bypass passage 24 is separated and independent from the first bypass passage 10, the humidity sensor 8 is not affected by the shape of the first bypass passage 10 or the shape of the entire air flow sensor 9. Integration is facilitated, and a highly versatile integrated structure that does not interfere with the performance and reliability of both sensors can be achieved. Therefore, it becomes possible to integrate the humidity detection device into various types of air flow measurement devices with the same technique, improving development and production efficiency, and providing stable humidity detection performance and reliability.

As shown in FIG. 2, the entire first bypass passage 10 is arranged in the middle of the intake pipe 2, whereas the second bypass passage 24 including the second bypass inlet 25 and the second bypass outlet 26 is It is arranged outside the intake pipe inner wall surface 27.

The property that the pollutant and water droplets are difficult to invade in the direction against gravity, and if the second bypass passage 24 is configured in a crank shape and long, even if dust in the atmosphere with small particles flows, most of the bypass passage wall surface It is a configuration that combines the characteristics that make it difficult to reach 20 parts of the humidity sensor element, and is an effective means for the humidity sensor 8 that is particularly sensitive to fouling and water droplet adhesion.

Further, in this configuration, the second bypass passage is formed by using the pressure difference between the high pressure portion generated when the air flowing through the main passage 1 collides with the front surface of the air flow sensor 9 and the low pressure portion generated near the rear end portion of the air flow sensor 9. Since the air flow can be generated inside 24, the second bypass inlet 25 is opened inside the mounting hole 3 of the sensor. With this configuration, the fouling resistance is further improved against fouling substances and water droplets flowing with air. Similarly, since the second bypass outlet 26 is also opened inside the sensor mounting hole 3, it has anti-fouling properties against engine oil mist or the like that flows backward from the engine side by convection after the engine is stopped. .

Also, by connecting the humidity measurement bypass passage outside the intake pipe, it becomes difficult for the pollutant to flow into the bypass. As a result, antifouling performance is improved, and the flow velocity inside the bypass for humidity measurement is achieved by receiving the dynamic pressure of the flow in the air introduction groove provided in the front of the housing and actively creating a pressure difference with the bypass outlet. Therefore, the responsiveness of the humidity sensor is improved.

According to the first embodiment of the present invention, both antifouling performance and measurement accuracy can be realized.

A second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a front structural view of the second embodiment of the present invention and its BB cross-sectional view.

The air introduction groove 28 is formed in a front portion where the air flowing through the main passage 1 collides with a part of the housing member 7. The air introduction groove 28 has a concave shape provided on the side wall surface where the forward flow flowing through the intake pipe 2 of the housing member collides, and the side wall surface of the housing member 7 is formed by the air introduction groove 28 and its peripheral edge 30 (peripheral edge). The saucer shape is formed in. The tray shape provided in the housing member 7 is formed so as to be disposed in both the region disposed in the intake pipe of the housing member 7 and the region disposed in the mounting hole of the sensor. A second bypass inlet 25 is provided at the bottom of the air introduction groove 28 so as to open. That is, since the air introduction groove 28 is configured to be continuously connected to the second bypass passage 24, the flowing air can be received by the air introduction groove 28 and guided to the second bypass passage 24 as it is. The air introduction groove 28 can increase the pressure in the vicinity of the second bypass inlet 25 and increase the pressure difference between the second bypass inlet 25 and the second bypass outlet 26. By adding the air introduction groove 28, the flow velocity inside the second bypass passage 24 can be further improved, so that the responsiveness of the humidity sensor 8 can be improved. Further, the introduction groove 28 is provided perpendicular to the air flowing through the intake pipe, and dust or the like that collides with the introduction groove 28 adheres to the introduction groove and is difficult to reach the second bypass inlet. Antifouling property is improved. According to the second embodiment of the present invention, the antifouling performance and measurement accuracy of the humidity sensor 8 can be achieved at a higher level.

A modification of the second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a sectional view taken on line BB of a modification of the second embodiment of the present invention.

3, an air introduction groove 28 is formed on the side wall surface on the backflow side of the housing member 7 similarly to the side wall surface on the forward flow side. When it is necessary to measure the humidity of the backflow caused by the intake air pulsation of the engine, the backflow measurement accuracy and antifouling property can be further improved.

A third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a front structural view showing a third embodiment of the present invention and its CC cross-sectional view.

A fouling trap surface 29 having a plurality of grooves in the direction perpendicular to the air flow direction was formed on the bottom surface of the air introduction groove 28.

Most of the fouling substances and water droplets flowing along with the air flowing inside the intake pipe 2 flow downstream or adhere to the bottom of the air introduction groove 28. The kind may flow into the second bypass passage 24. Therefore, a plurality of grooves are provided on the bottom surface of the air introduction groove 28 in a direction perpendicular to the air flow direction so that the pollutant does not enter the second bypass passage 24 by adhering to the groove. Similarly, since the water droplet is also viscous, it is caught in the groove of the fouling trap surface 29 and cannot enter the second bypass passage 24.

If the same structure is also formed on the bottom surface of the downstream air introduction groove 28, it flows with engine oil mist flowing back from the engine side by convection after the engine is stopped, or back flow caused by engine intake pulsation. Similar effects can be obtained with respect to the fouling substances.

According to the third embodiment of the present invention, it is possible to make it more difficult for contaminants such as dust to enter the second bypass passage 24, so that the stain resistance is improved and both the stain resistance and the measurement accuracy are achieved at a high level. be able to.

A fourth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a front structural view showing a fourth embodiment of the present invention.

The edge 30 around the air introduction groove 28 was partly cut out to form an asymmetric shape, not a saucer shape. This is an effective means particularly when applied to an application where water droplets are highly likely to scatter. When water droplets adhere to the fouling trap surface 29, the water droplets flow along the grooves formed in the fouling trap surface 29, so that the water can be drained from the edge notch portion to the downstream side of the apparatus. In particular, the fouling performance against water droplets is particularly improved. According to the fourth embodiment of the present invention, both antifouling properties and measurement accuracy can be achieved at a higher level.

A fifth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a sectional view showing a fifth embodiment of the present invention.

A trap groove 31 was formed on the inner wall surface of the second bypass passage 24 formed in the housing member 7. The contaminants that have not been captured by the means described up to FIG. 6 and have flowed into the second bypass passage 24 are trapped to prevent the contaminants from reaching the humidity sensor element 20.

Also, the trap groove 31 can disturb the air flowing inside the second bypass passage 24. If there is a distribution (unevenness) in the moisture content of the air flowing inside the second bypass passage 24, the correct humidity cannot be measured. When supplied to the sensor element 20, the measurement accuracy is also improved. In addition, since this trap groove 31 is not suitable for the air flow rate sensor 9 in which the turbulence affects the measurement, in this configuration, the trap groove 31 is not installed in the first bypass passage 10 installed separately and independently. A trap groove 31 is formed only in the second bypass passage 24.

Although the groove shape is proposed in FIG. 7, the main purpose is a trapping structure for fouling substances. Therefore, an uneven shape that is not a groove is applied, or an adhesive material is placed on the inner wall surface of the second bypass passage 24. However, the same effect can be obtained.

A sixth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a sectional view showing a sixth embodiment of the present invention.

A humidity / humidity sensor element 40 was mounted on the humidity sensor electronic circuit board 21 instead of the humidity sensor element 20, and a pressure sensor element 41 was also mounted in the vicinity thereof. When this apparatus is used for controlling an internal combustion engine of an automobile, a necessary physical quantity related to humidity is absolute humidity. In order to obtain this absolute humidity, the temperature signal output from the temperature / humidity sensor element 40 and the relative humidity signal are used. In addition, a pressure signal from the pressure sensor element 41 is required.

Furthermore, in order to obtain a good accuracy as the absolute humidity, the temperature information and pressure information at the point at which the relative humidity is measured are required. For this reason, the pressure sensor element 41 is very much the temperature / humidity sensor element 40. It was necessary to be in the vicinity.

The case where the air physical quantity detection device 5 of the present invention is applied to an electronic fuel injection internal combustion engine will be described with reference to FIG.

The intake air 51 sucked from the air cleaner 50 passes through an intake manifold 55 having an intake pipe 2 into which the air physical quantity detection device 5 is inserted, an intake duct 52, a throttle body 53, and an injector 54 to which fuel is supplied, and then an engine cylinder. 56 is inhaled. On the other hand, the gas 57 generated in the engine cylinder 56 is discharged through the exhaust manifold 58.

The air physical quantity signal output from the air physical quantity detection device 5, the throttle valve angle signal output from the throttle angle sensor 59, the oxygen concentration signal output from the oxygen concentration meter 60 provided in the exhaust manifold 58, and the engine speed The control unit 62 that inputs the engine rotational speed signal output from the meter 61 and the like sequentially calculates these signals to obtain the optimum fuel injection amount and the optimum output torque, and uses the values to determine the injector 54 and the like. The throttle valve 63 is controlled.

DESCRIPTION OF SYMBOLS 1 Main passage 2 Intake pipe 3 Sensor mounting hole 4 Seal member 5 Air physical quantity detection device 6 Connector 7 Housing member 8 Humidity sensor 9 Air flow sensor 10 First bypass passage 11 Base member 12 First bypass component 13 Air flow sensor element 14 Temperature Compensating Element 15 Temperature Sensor 16 Terminal Member 17 Metal Wire 18 Air Flow Sensor Electronic Circuit Board 19 Air Flow Sensor Connector Terminal 20 Humidity Sensor Element 21 Humidity Sensor Electronic Circuit Board 22 Humidity Sensor Connector Terminal 23 Coating Member 24 Second bypass passage 25 Second bypass inlet 26 Second bypass outlet 27 Intake pipe inner wall surface 28 Air introduction groove 29 Fouling trap surface 30 Surrounding edge 31 Trap groove 40 Temperature / humidity sensor element 41 Pressure sensor element 50 Air cleaner 51 Intake air 52 Intake air 53 Throttle body 54 Injector 55 Intake manifold 56 Engine cylinder 57 Gas 58 Exhaust manifold 59 Throttle angle sensor 60 Oxygen concentration meter 61 Engine speed meter 62 Control unit 63 Throttle valve

Claims

In the intake physical quantity detection device that detects the physical quantity of air flowing through the intake pipe by inserting it into the insertion port of the intake pipe,
A housing member integrally comprising the attachment portion to the intake pipe, a connector and a connector terminal member,
A first bypass passage for taking in part of the fluid flowing in the intake pipe;
A flow rate detecting element provided in the first bypass passage;
A second bypass passage provided separately and independently from the first bypass passage;
A humidity detecting element provided in the second bypass passage,
The second detection element is mounted on the portion that will be located outside the inner wall surface of the intake pipe,
The air physical quantity detection device according to claim 1, wherein the inlet opening of the second bypass passage is provided on a side wall surface on a forward flow side of the housing member.
In the air physical quantity detection device according to claim 1,
The whole of the first bypass passage is located inside the intake pipe, and the whole or at least part of the second bypass passage is located outside the inner wall of the intake pipe. .
In the air physical quantity detection device according to claim 2,
A tray-shaped first groove communicating with one opening of the second bypass passage is formed on a surface of the housing where the one opening of the second bypass passage is provided. Physical quantity detection device.
In the air physical quantity detection device according to claim 3,
The other opening of the second bypass passage is open on the surface of the housing opposite to the surface on which the one opening of the second bypass passage is provided, and the second bypass passage of the housing An air physical quantity detection device characterized in that a receiving plate-like second groove communicating with the other opening of the second bypass passage is formed on a surface on which the other opening is provided.
In the air physical quantity detection device according to claim 4,
A plurality of irregularities are formed on the bottom surface of either or both of the first groove and the second groove.
In the air physical quantity detection device according to claim 5,
An air physical quantity detection device, wherein a part of an edge constituting the first groove and the second groove is cut out.
In the air physical quantity detection device according to claim 1,
An air physical quantity detection device, wherein irregularities are formed on the inner wall surface of the second bypass.
In the air physical quantity detection device according to claim 1,
An air physical quantity detection device, wherein a humidity detection element and a pressure detection element are mounted inside the second bypass passage.
A housing member integrally comprising a mounting portion, a connector and a connector terminal member;
A first bypass passage;
A flow rate detecting element provided in the first bypass passage;
A second bypass passage provided separately and independently from the first bypass passage;
A humidity detecting element provided in the second bypass passage,
The first bypass passage side below the attachment portion is below the attachment portion, and the humidity detection portion is provided above the attachment portion,
The air physical quantity detection device according to claim 1, wherein the inlet opening of the second bypass passage is provided on a side wall surface of the housing member having a smaller area.