JPH11101676A - Air flow measuring device and fuel injection control system for internal combustion engine using the same - Google Patents

Abstract

(57) [Problem] To provide an air flow measuring device that reduces variation in mounting angle and improves output characteristics with high accuracy. An air flow measuring device includes a sheet metal base having an electronic circuit board mounted at a central portion and having a mounting hole at a base corner, and a base peripheral portion excluding the base corner.
a housing 1 made of resin molded so as to cover the periphery of the electronic circuit board 2 while holding the insert d. The base corner 27 b exposed from the outer peripheral surface of the housing 1 is mated through the mounting hole 33. The housing 1 attached to the body 50 of the side attachment member has a body fitting portion of the body 50 on the outer peripheral surface of the housing 1 near the base corner 27b.
It has a housing fitting portion 1a that fits into the 50a and suppresses relative movement when the base 27 is mounted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure of a heating resistor type air flow measuring device for measuring an air flow using a hot wire.

[0002]

2. Description of the Related Art As a device for measuring the flow rate of air taken into an internal combustion engine, there is an air flow measurement device of a heating resistor type using a hot wire or the like, and the air flow measurement device radiates heat from the hot wire. Since a signal corresponding to the mass flow rate of the air flowing through the intake pipe is obtained, it is widely and practically used today as the most suitable one for air-fuel ratio control of an internal combustion engine. This air flow measurement device has a sensing section mainly including a temperature-sensitive resistor disposed in an intake pipe of an internal combustion engine, a flow measurement section including an electronic circuit and the like connected thereto, and holds the flow measurement section. And a resin housing for protection. A module composed of the sensing section, the flow rate measuring section, the housing, and the like is generally called a module, and the module is attached to an outer wall surface of an intake pipe which forms a main air passage through which most of the intake air flows. Is measured.

[0003] In order to improve the measurement accuracy of the air flow measuring device, it is important to suppress variations in mounting the module to an intake pipe of an internal combustion engine. In other words, it is important to keep the relative movement between the air flow measuring device and the intake pipe small. This is because the sensing unit that measures the air flow velocity is located in the sub air passage that allows a part of the intake air to flow for the purpose of protecting itself and improving performance, so the main air passage, the sensing unit, and the sub air passage Relative position relationship (mounting dimensions and angles)
This is because if the variation occurs, the flow velocity distribution in the sub air passage changes, or the measurement point of the sensing unit shifts, causing an error. Compared with other intake air temperature sensors and pressure sensors attached to the intake pipe, in the case of the air flow measurement device, if there is a variation in the installation, it will lead to a measurement error of the air flow, so ensuring this installation accuracy It is important.

[0004] When a module is inserted into an insertion hole provided in the outer wall surface of the intake pipe component and mounted, the mounting variation in one module insertion direction depends on the flatness of the mounting surface and the other module rotation. The mounting angle as the mounting variation in the direction is caused by the backlash during the mounting (the above-described relative movement). As a technique for controlling these mounting variations, there is a technology disclosed in Japanese Patent Application Laid-Open No. Sho 59-31412. According to this technology, the mounting variation in the insertion direction is prevented by adding a metal to the resin housing. The collar member is made by insert molding, and the variation is suppressed from the flatness of the collar member. With respect to the other rotation direction, the convex step provided in the center portion (bottom side) of the housing is fitted to the concave step provided in the insertion hole of the body as an intake pipe component, and the backlash ( Relative movement).

[0005]

However, in the above-mentioned prior art, the influence of heat shrinkage of the resin limits the variation in mounting, especially the suppression of the mounting angle with respect to the rotation direction, and the measurement of the air flow from the point of mounting. There is a problem that further improvement of the measurement accuracy of the device cannot be expected. This problem,
This also affects the accuracy of the air-fuel ratio control of the internal combustion engine. Hereinafter, this problem will be described with reference to FIGS. In the air flow measuring device of the prior art shown in FIGS. 11 and 12, since the collar member 24 is inserted into the resin housing 1, the outer diameter of the mounting screw 7 should be adjusted in consideration of the influence of heat shrinkage. Therefore, it is necessary to give a certain margin (gap) to the inner diameter of the mounting hole 33 of the collar member 24. For this reason, rattling (relative movement) when mounting the module increases, and a large variation occurs in the mounting angle.

On the other hand, with respect to a step 9 provided substantially near the center of the housing 1 in which the sensing section is provided,
In consideration of the heat shrinkage of the resin, it is necessary to make a large gap with a concave step (not shown) provided in the insertion hole 25 of the body 50 to be fitted. The reason for this is that, considering that the electronic circuit board 2 is fixed to the inner surface of the housing 1 opposite to the outer surface on which the sensing portion is installed, the step 9 located near the center of the housing 1 is fitted. The combined dimensions must be designed with the minimum dimensions (minimum tolerance) for the purpose of restricting horizontal positioning including the rotation direction when assembling the module. Interference between steps becomes a problem, and if the screws are tightened with the interference, the housing 1
Of the electronic circuit board 2 installed on the opposite surface of the step 9 provided in the housing 1. In addition, the above-mentioned interference problem leads to markedly worsening of workability, and lowers productivity.
For this reason, in consideration of the heat shrinkage of the resin and the improvement of work efficiency, it is necessary to increase the clearance in order to fit the step (not shown) provided in the body 50 and the step 9 provided in the housing 1. With such a large clearance, it is impossible to increase the mounting angle accuracy in the horizontal direction including the rotation direction of the module.

Accordingly, an object of the present invention is to suppress the relative movement of the air flow measuring device attached to the mating mounting member, reduce the variation in the mounting angle, etc., and measure the intake air flow accurately. It is to provide a device.

It is another object of the present invention to provide a fuel injection control system for an internal combustion engine that can accurately control the air-fuel ratio of the internal combustion engine.

[0009]

A feature of the air flow measuring device according to the present invention which achieves the above object is that a base made of a sheet metal having a flow rate measuring section mounted thereon and having a mounting hole at a corner portion, and a base holding the base. A resin housing molded so as to cover the periphery of the flow rate measuring section, wherein the corner of the base is attached to a mating mounting member via a mounting screw passed through the mounting hole. In addition, the base corner is located at a position exposed from an outer peripheral surface of the housing.

As another feature, the housing is fitted on the outer peripheral surface of the housing near the corner of the base and is fitted into the mating mounting member so as to be formed in a gap between the mounting hole and the mounting screw. It is preferable to have a housing fitting part for suppressing movement.

Another feature is that a base made of a sheet metal on which the flow rate measuring section is mounted, and a resin molded to cover around the flow rate measuring section while holding the base with mounting holes at the corners. An air flow measurement device, comprising: a housing made of a material, wherein the housing is mounted to a mating mounting member via a mounting screw passing through the mounting hole, wherein the base is located near a corner of the housing from the housing. There is an exposed base fitting portion, and the base fitting portion is fitted to the mating mounting member and suppresses relative movement generated in a gap between the mounting hole and the mounting screw.

Still another feature is that a resin housing is molded so as to cover around a built-in flow rate measuring portion while holding a collar member for mounting the housing at a corner portion, and the housing is formed of a resin. An air flow measuring device attached to a counterpart mounting member via a mounting screw passed through the collar member, wherein the collar member is fitted to the counterpart mounting member and a gap between the collar member and the mounting screw is provided. In that it has a collar fitting portion for suppressing relative movement caused by the above.

[0013] On the other hand, in the fuel injection control system for an internal combustion engine according to the present invention, the air flow measuring device according to any one of claims 1 to 5 is mounted in an intake pipe and output from the air flow measuring device. The fuel injection control of the internal combustion engine is performed using the flow rate signal.

According to the present invention, since the backlash (relative movement) at the time of mounting the air flow measuring device is reduced, the intake air flow rate can be measured accurately.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded view showing an air flow measuring device according to an embodiment of the present invention. In the figure, an air flow measuring device 40 of the first embodiment is shown.
Is an electronic circuit board 2 as a flow rate measuring unit for measuring an air flow rate, and the electronic circuit board 2 is mounted at a substantially central portion to form a base corner portion.
A sheet metal base 27 having a mounting hole 33 in 27b, a resin housing 1 for insert holding (embedding holding) a base peripheral portion 27d excluding a central portion 27e and a base corner 27b of the base 27; A sensing portion including a heating resistor 3, a temperature-sensitive resistor 4, and a conductive support 5; a sub air passage 10 including the sensing portion and fixed to the housing 1; and an electronic circuit board 2 attached to the housing 1 And a cover 26 that covers the cover. Hereinafter, the above air flow measurement device
40 is also called a module.

The heating resistor 3 and the temperature-sensitive resistor 4
Are supported by a conductive support 5 while being electrically connected to the electronic circuit board 2. The support 5 is embedded and supported in the housing 1. The sub air passage 10 is held in the housing 1 by fitting the protrusion 28 into the bonding groove 30 and bonding it. The electronic circuit board 2 is mounted on a central portion 27e on the base 27 by bonding or the like. Accordingly, the sensing portion connected to the electronic circuit board 2, the sub air passage 10 including the sensing portion, the insertion hole 25 of the body 50 as a mating attachment member into which the sub air passage 10 is inserted, and the like are provided by the air flow measuring device. It is located in the approximate center of 40. In addition, the base 27
The base has a mounting hole 33 for mounting the base itself to the body 50 at a base corner 27b at a position distant from the center 27e on which the electronic circuit board 2 is mounted.

Further, the housing 1 is a case in which the electronic circuit board 2 is incorporated. The electronic circuit board 2 is mounted on the central portion 27e, and the base 27 has a mounting hole 33 at the base corner 27b.
Of the base except for the central part 27e and the base corner 27b
It is molded so as to surround the side surface of the electronic circuit board 2 over substantially the entire circumference so as to protect the electronic circuit board 2 while burying and holding 27d. Further, the housing 1 receives power from a battery (not shown) and
This is a configuration in which a connector 31 that protects a connector terminal 32 serving as an interface for sending an output signal from the control unit (not shown) to a control unit (not shown) is integrally molded. In addition, the base corner 27b as a portion near the mounting hole 33 is not buried in the housing 1 but is exposed and extended from the outer peripheral surface of the housing 1 to be molded.

The air flow measuring device 40 having the above configuration
In other words, the sub air passage 10 of the module is inserted into the insertion hole 25 of the body 50 as the mating mounting member, and the base corner 27b is inserted into the mounting hole 7 through the mounting hole 33. Attached to the body 50
Assembled in At this time, the sealing member 6 seals the space between the module and the body 50, and the flow rate of the air flowing inside the body 50 is correctly measured. Body 50 in this case
Is a mating attachment member to which the air flow measuring device 40 is attached, and is generally constituted by a metal intake pipe constituent member constituting a part of the intake pipe. Note that the air flow measuring device of the present invention can be defined as an air flow measuring device having an assembly configuration including a module and a body. On the other hand, the sealing material 6 made of an O-ring or the like seals between the housing 1 and the insertion hole 25 of the body 50. The mounting of the air flow to be measured to the body 50 forming the main air passage 22 is performed via the mounting screw 7.

As described above, the base corner 27b having the mounting hole 33 for fastening the air flow measuring device 40 to the body 50 with the mounting screw 7 is extended from the outer peripheral surface of the housing 1. 11 and 12 of the prior art, a cylindrical metal collar member 24 (that is, a mounting hole is formed) for mounting the housing 1 to the body 50 shown in FIGS. ) Can be made to a negligible level as compared with a resin housing 1 inserted into a resin housing 1.

That is, one sheet metal base 27 has less thermal expansion than resin, and the pitch dimension of the mounting holes 33 provided in the base 27 (and the screw holes provided in the mounting holes 33 and the body 50). Since the deviation due to thermal expansion of the mounting hole 33 (the relative position with respect to 50b) is reduced, the inner diameter of the mounting hole 33 (that is, the fitting tolerance or gap between the outer diameter of the mounting screw 7) is smaller than that of the prior art. It can be set smaller than the inner diameter of the collar member 24 (the above-described fitting tolerance and gap size). By improving the inner diameter dimensional accuracy of the mounting hole 33 (the above-described fitting tolerance and gap size), rattling (relative movement between the module and the body 50) generated in the gap between the mounting hole 33 and the mounting screw 7 can be reduced. Hold down,
Variations in mounting angle and the like can be reduced. On the other hand, since the base 27 is made of sheet metal, the flatness of the module mounting surface 27c of the base corner 27b that comes into contact with the body 50 during mounting can be ensured. By ensuring this flatness, it is possible to reduce the variation in the mounting in the module insertion direction.

Next, positioning means for further reducing the variation in the mounting angle in the horizontal direction including the rotation direction of the air flow measuring device of the first embodiment (ie, the direction perpendicular to the module insertion direction) will be described. 2 and FIG. FIG. 2 is an enlarged sectional view showing a mounting portion of the air flow measuring device of FIG. FIG. 3 is a bottom view of the air flow measuring device of FIG. FIG. 2 shows a view of the module shown in FIG. 1 as viewed from below.

In FIG. 2, mounting holes for mounting the base 27 are shown.
The feature of the positioning means that suppresses the relative movement generated in the gap between the mounting screw 33 and the mounting screw 7 is that the fastening force (rotational force) when the base 27 is mounted on the body 50 of the mating mounting member (via the air flow measuring device 40). The housing 1 is fitted (or abutted) with the body fitting portion 50a so that the base 27 and the housing 1 integrally formed with the base 27 do not move (rotate) due to the force), and the relative movement is performed. A housing fitting portion 1a (or a housing contact portion) as a positioning means for suppressing is provided near the base corner portion 27b.

That is, the insertion hole 25 of the body 50 is circular because the sealing member 6 of an O-ring is often used from the viewpoint of sealing performance and simplicity.
It is necessary to suppress rotation of 40. Then, the housing fitting portion 1a (or a contact portion formed of a step) as a horizontal positioning means including the rotation direction is set as a position farthest from the (center of) the insertion hole 25 located at the substantially central portion. Is provided near the base corner 27b at a position exposed and extended from the outer peripheral surface of the housing 1, so that the positioning is performed by a step 9 provided at a substantially central portion of the housing 1 of the prior art. Even with the same allowable minimum clearance dimension (allowable fitting tolerance) in resin molding,
It is possible to reduce the variation in the mounting angle in the horizontal direction including the rotation direction. In other words, the relative movement generated in the gap between the mounting hole 33 and the mounting screw 7 can be suppressed, and the variation in the mounting angle and the like can be reduced. Therefore, the efficiency of the screw mounting operation when the air flow measuring device 40 is mounted on the body 50 can be improved, and the relative movement during mounting can be suppressed to minimize the dimensional variation.

Next, an air flow measuring device according to another embodiment of the present invention will be described with reference to FIGS. FIG. 4 is an enlarged sectional view showing a mounting portion of an air flow measuring device according to another embodiment of the present invention. FIG. 5 is a partial bottom view showing a mounting portion of the air flow measuring device of FIG.

In the figure, an air flow measuring device 40 according to the second embodiment includes a resin housing 1 surrounding the base 27 so as to protect the electronic circuit board 2 while burying and holding (insert holding) the base 27, An electronic circuit board 2 as a measuring unit, a cover 26 attached to the housing 1 and covering the electronic circuit board 2, and a sheet metal base 27 on which the electronic circuit board 2 is mounted at a substantially central portion. Is done. The housing 1 is inserted from substantially the center of the housing 1 on which the electronic circuit board 2 is disposed, that is, the insertion hole of the body 50.
Housing corner 1b away from 25 (center of hole)
In addition, a configuration is provided in which a cylindrical metal collar member 24 for attaching the housing 1 itself to the body 50 is provided. In addition,
A configuration not using the collar member 24 (not shown), that is, a configuration having only the mounting hole 33 in the housing corner 1b of the housing 1 may be employed.

Further, the feature of the positioning means of the second embodiment which suppresses the relative movement when the housing 1 is mounted is as follows. The mounting structure of the air flow measuring device 40 (the housing 1) and the body 50 is the same as that of the prior art using the collar member 24, but is integrally molded by the housing 1 to bury the base peripheral portion 27d. As shown in FIG. 5, the base 27 has a base fitting portion 27a that draws an arc shape near the housing corner 1b of the housing 1, and the base fitting portion 27a is formed by the housing 1. There is a configuration in which a molded shape is exposed from the housing 1 so as to avoid being buried.

As shown in FIG. 4, the fastening force (rotational force) when the housing 1 is attached to the body 50 of the mating attachment member (via the air flow measuring device 40).
In order to prevent the housing 1 and the base 27 inserted and held in the housing 1 from moving (rotating), the base 27 is fitted with the base fitting portion 27a of the base 27 with the body fitting portion 50a.
(Or abut), a base fitting portion 27a (or a base abutting portion) as a positioning means for suppressing relative movement,
It is provided near the housing corner 1b.
Structures other than the above are the same as those of the first embodiment, and the components denoted by the same reference numerals are the same as those of the first embodiment.

According to the air flow measuring device 40 having the above configuration,
Base fitting portion 27a of base 27 made of sheet metal with small heat shrinkage
Also, the positioning is performed according to the step-shaped body fitting portion 50a provided on the body 50 (the intake pipe constituent member made of metal or hard resin) also having a small heat shrinkage. 7 to suppress the relative movement that occurs in the gap,
Variations in mounting angle and the like can be reduced.

In the case of the second embodiment, the above-described first embodiment is used.
Since the influence of heat shrinkage of the resin is further reduced as compared with the embodiment, the mounting dimensional accuracy can be further improved. On the other hand, the metal collar member 24 which comes into contact with the body 50 at the time of mounting reduces the mounting variation in the module insertion direction from the flatness of the collar member 24 itself.

Further, an air flow measuring device according to a third embodiment of the present invention will be described with reference to FIG. FIG. 6 is an enlarged sectional view showing a mounting portion of an air flow measuring device according to another embodiment of the present invention. In FIG. 6, the air flow measuring device 40 of the third embodiment is a resin molded by molding so as to cover the periphery of the electronic circuit board 2 built therein while inserting and holding the housing mounting collar member 24 in the housing corner 1b. The housing 1 is provided with a housing 1 and the housing 1 is attached to the body 50 of the mating attachment member via the collar member 24. The collar member 24 has a collar fitting portion 24a as a positioning means that fits into the body fitting portion 50a of the body 50 and suppresses relative movement when the housing 1 is mounted.

That is, the base 27 is fixed to the housing 1 by bonding or the like without being insert-molded in the housing 1. The mounting structure of the housing 1 and the body 50 is the same as that of the air flow measuring device 40 of the second embodiment.
It is configured to be attached using a collar member 24 made of a tubular metal. Further, the features of the positioning means of the third embodiment for suppressing the co-rotation due to the fastening force when the housing 1 is mounted are as follows. The metal collar member 24 provided on the housing corner 1b of the housing 1 has a configuration in which a convex collar fitting portion 24a protruding from the mold surface of the housing 1 is provided. In other words, the housing 1 does not move (rotate) so that the housing 1 does not move (rotate) due to the fastening force (rotational force) when the housing 1 (that is, the air flow measuring device 40) is attached to the body 50 of the mating attachment member. The collar member 24 provided on the body 50 has a configuration in which a collar portion 24a of a convex portion as a positioning means for fitting into the concave portion of the body fitting portion 50a of the body 50 and suppressing relative movement is provided. . Other configurations other than the above are the same as the configuration of the first embodiment.
The parts denoted by the same reference numerals are the same as the parts of the first embodiment.

The air flow measuring device 40 including the positioning means by fitting the collar fitting portion 24a provided on the collar member 24 and the body fitting portion 50a provided on the body 50 as described above has the following features. Variations in mounting in the horizontal direction including the rotation direction of the device 40 are reduced. Since the mounting variation in the module insertion direction is reduced due to the flatness of the metal collar member 24 itself, it is possible to provide an air flow measuring device with improved output characteristic accuracy.

Next, a fuel injection control system for an internal combustion engine using the air flow measuring device according to the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 7 is a sectional view showing an attached state of the air flow measuring device of one embodiment according to the present invention, and FIG. 8 is a front view showing an attached state of the air flow measuring device of FIG. FIG. 8 is an external view as viewed from the upstream side (the left direction in FIG. 7).

First, the air flow measuring device 40 will be described from the state of attachment. It has a housing 1 containing an electronic circuit board 2 and a sub air passage 10 formed of a non-conductive material. The heating resistor 3 for detecting an air flow rate and the intake air temperature in the sub air passage 10 are provided. The temperature-sensitive resistor 4 for compensating is electrically connected to the electronic circuit board 2 via a support 5 made of a conductive material, and includes a housing 1, an electronic circuit board 2, an auxiliary air passage 10, and a heating resistor 3. The air flow measuring device 40 which forms a module by integrating the temperature sensing resistor 4 and the like is fixed to a body 50 forming a main air passage 22 through which intake air flows. That is, the insertion hole 25 is formed in the wall surface of the body 50, and the sub air passage 10 of the air flow measuring device 40 is inserted into the insertion hole 25 from outside, and the body 50
And the housing 1 of the air flow measuring device 40
It is fixed so as to maintain the mechanical strength. At this time, the seal member 6 is attached between the sub air passage 10 and the body 50 to maintain airtightness.

Next, the operation of the air flow measuring device 40 will be described. FIG. 9 is a diagram showing a drive circuit of the air flow measuring device of FIG. The air flow measuring device 40 includes a temperature-sensitive resistor RH disposed in a body 50 forming an air flow path.
(That is, the heating resistor 3), the temperature-sensitive resistor RC for compensating the intake air temperature (that is, the temperature-sensitive resistor 4), and a drive circuit in which a bridge is formed by R10 and R11. In this drive circuit, a heating current Ih is supplied to the heating resistor RH to generate heat, and at this time, the magnitude of the supply current Ih is controlled so as to maintain a constant temperature difference between the heating resistor RH and the temperature-sensitive resistor RC. When air flows, the amount of heat deprived from the heating resistor RH increases, and the ratio changes according to the speed at which the air flows, that is, the air flow velocity, and the value of the current required for heating also changes. As a result, the magnitude of the current flowing through the heating resistor becomes a value corresponding to the air flow velocity, and the air flow rate is measured by converting the cross-sectional area of the air flow path into the air flow rate.

The output signal Vout (heating current) representing the detected air flow rate is converted into a voltage signal or a frequency or current value signal, and is sent from the air flow rate measuring device 40 to a control unit to be described later. Output as a signal.

Next, a fuel injection control system for an internal combustion engine using the air flow measuring device of the present invention will be described.
FIG. 10 is a diagram showing a fuel injection control system for an internal combustion engine according to one embodiment of the present invention. The configuration and operation of the fuel injection control system are as follows. In the figure, the intake air 67 that has been taken in is taken by an air cleaner 54, a body 53 on which a module 52 is mounted, an intake duct 55, and a throttle body.
The fuel is sucked into the engine cylinder 62 through an intake pipe constituting member such as an intake manifold 59 having an injector 60 to which fuel is supplied. On the other hand, the gas 63 generated in the engine cylinder 62 is supplied to the exhaust manifold 64
Is discharged through.

Module 52 as air flow measuring device 40
, An intake air temperature signal from an intake air temperature sensor 51, a throttle valve angle signal output from a throttle angle sensor 57, an oxygen concentration signal output from an oximeter 65 provided in an exhaust manifold 64, The control unit 66, which inputs an engine speed signal and the like output from the engine speed meter 61, sequentially calculates using these signals to obtain an optimal fuel injection amount and an idle air control valve opening degree. The value is used to control the injector 60 and the idle control valve 56.

Thus, the control unit 66
In the fuel injection control system in which the control of the fuel injection amount with respect to the intake air amount of the internal combustion engine (i.e., the air-fuel ratio control) is performed by the air flow measuring device 40 according to the present invention mounted in the intake pipe, If a signal is used, there is no error in the measurement of the air flow rate, so that it can be said that optimal fuel injection amount control, that is, accurate air-fuel ratio control is ensured.

[0040]

According to the present invention, the relative movement between the air flow measuring device and the counterpart mounting member when the air flow measuring device is mounted on the counterpart mounting member is suppressed, and variations in the mounting angle and the like are minimized. Therefore, it is possible to provide an air flow measurement device that achieves high accuracy in flow measurement.

Further, by controlling the fuel injection of the internal combustion engine using the flow signal from the air flow measuring device according to the present invention installed in the intake pipe, the fuel injection amount can be controlled with high accuracy. The combustion efficiency of the engine is improved.

[Brief description of the drawings]

FIG. 1 is an exploded view showing an air flow measuring device according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a mounting portion of the air flow measuring device of FIG.

FIG. 3 is a bottom view of the air flow measuring device of FIG. 2;

FIG. 4 is a sectional view showing a mounting portion of an air flow measuring device according to another embodiment of the present invention.

FIG. 5 is a partial bottom view showing a mounting portion of the air flow measuring device of FIG. 4;

FIG. 6 is an enlarged sectional view showing a mounting portion of an air flow measuring device according to another embodiment of the present invention.

FIG. 7 is a sectional view showing an attached state of the air flow measuring device of one embodiment according to the present invention.

FIG. 8 is a front view showing an attached state of the air flow measuring device of FIG. 7;

FIG. 9 is a diagram showing a drive circuit of the air flow measuring device of FIG. 7;

FIG. 10 is a diagram showing a fuel injection control system for an internal combustion engine according to one embodiment of the present invention.

FIG. 11 is an exploded configuration diagram illustrating a conventional air flow measuring device.

FIG. 12 is a bottom view illustrating the air flow measuring device of FIG. 11;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Housing, 1a ... Housing fitting part, 1b ... Housing corner part, 2 ... Electronic circuit board, 3 ... Heating resistor, 4 ...
Temperature sensing resistor, 5: support, 6: sealing material, 7: mounting screw, 9: step, 10: sub air passage, 11: sub air passage inlet,
12 ... Sub air passage outlet, 13 ... Vertical passage, 14 ... Horizontal passage, 22 ... Main air passage, 23 ... Air flow, 24 ... Collar member, 24a ... Collar fitting part, 25 ... Insertion hole, 26 ... Cover, 27 ... Base, 27a
... Base fitting part, 27b ... Base corner, 27c ... Module mounting surface, 27d ... Base peripheral part, 27e ... Central part, 28 ... Protrusion, 30 ... Adhesive groove, 31 ... Connector, 32 ... Connector terminal, 33 ... Mounting Hole, 40 ... air flow measuring device, 50 ... body,
50a: body fitting portion, 51: intake temperature sensor, 52: module, 53: body, 54: air cleaner, 55: suction duct, 56: idle air control valve, 57: throttle angle sensor, 58: throttle body, 59 ... Intake manifold, 60… Injector, 61… Engine speedometer, 62… Engine cylinder, 63… Gas, 64… Exhaust manifold, 65… Oxygen meter, 66… Control unit,
67… Intake air.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Kaoru Uchiyama 2520 Ojitakaba, Hitachinaka City, Ibaraki Prefecture Inside the Automotive Equipment Division of Hitachi, Ltd. (72) Shinya Igarashi 2477 Takaba, Hitachinaka-shi, Ibaraki Inside Hitachi Car Engineering (72) Inventor Chihiro Kobayashi 2520 No. Odaiba, Hitachinaka City, Ibaraki Prefecture Inside the Automotive Equipment Division, Hitachi, Ltd. (72) Takashi Kadohiro 2477 Takaba, Hitachinaka City, Ibaraki Prefecture Hitachi Car Co., Ltd. Within engineering

Claims (5)

[Claims] 1. A base made of a sheet metal on which a flow measuring unit is mounted and having a mounting hole at a corner portion, and a resin housing molded so as to cover around the flow measuring unit while holding the base. An air flow measuring device in which a corner of the base is attached to a mating mounting member via a mounting screw that passes through the mounting hole, wherein the base corner is exposed from an outer peripheral surface of the housing. An air flow measuring device characterized by the above-mentioned. 2. The relative movement of the housing according to claim 1, wherein the housing is fitted on the outer peripheral surface of the housing in the vicinity of the base corner and is fitted in the mating mounting member, and is generated in a gap between the mounting hole and the mounting screw. An air flow measuring device having a housing fitting portion for suppressing the air flow. 3. A sheet metal base on which a flow measuring unit is mounted,
A resin housing molded to cover around the flow rate measuring portion while holding the base and having a mounting hole in a corner portion, wherein the housing is mated through a mounting screw passed through the mounting hole. An air flow measuring device attached to a side mounting member, wherein the base has a base fitting portion exposed from the housing in the vicinity of a corner of the housing, and the base fitting portion is the mating side mounting member. The air flow measuring device is characterized in that the air flow measuring device is fitted to the mounting hole and suppresses a relative movement generated in a gap between the mounting hole and the mounting screw. 4. A mounting screw made of a resin molded so as to cover around a built-in flow rate measuring portion while holding a collar member for mounting the housing at a corner portion, and wherein the housing is threaded through the collar member. An air flow measuring device attached to a mating attachment member through a collar, wherein the collar member is fitted to the mating attachment member to suppress relative movement generated in a gap between the collar member and the mounting screw. An air flow measuring device having a fitting portion. 5. The fuel injection control of an internal combustion engine using the air flow measuring device according to any one of claims 1 to 5 mounted in an intake pipe and using a flow signal output from the air flow measuring device. A fuel injection control system for an internal combustion engine.