JP3383779B2 - Heating resistance type flow measurement device and internal combustion engine control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate measuring device using a heating resistor as a detecting element, and more particularly to a flow rate measuring device suitable for flow rate measurement when there are many pulsations such as the intake air flow rate of an internal combustion engine. Regarding

[0002]

2. Description of the Related Art In recent years, in internal combustion engines such as gasoline engines, measurement of the intake air flow rate has become an almost indispensable requirement for controlling the fuel supply amount from the viewpoint of exhaust gas pollution and energy saving. It can be said that the engine control device equipped with the intake air flow meter occupies the mainstream.

By the way, there is a heating resistor type flow rate measuring device as a kind of measuring device used for measuring such a fluid flow rate, which is widely used for engine control because it has excellent responsiveness and high reliability. ing.

By the way, there is a pulsation of the intake air flow rate as a characteristic of a general internal combustion engine. Therefore, as a heating resistor type flow rate measuring device, a sub passage is used to reduce the influence of the pulsation. By-pass type) heating resistor type flow rate measuring device has been conventionally used.

Also in this sub-passage type heating resistor type flow rate measuring device, for example, in Japanese Patent Laid-Open No. 8-5427, the sub-passage is integrated with a part of the flow rate measuring circuit module, and the heating resistance type air flow rate measurement is performed. The structure in which all the necessary functions are provided as a single module, and, for example, in Japanese Examined Patent Publication No. 4-75385, the air passage by the auxiliary passage is larger than the length of the auxiliary passage member along the main passage mainstream direction. We are proposing each of the technologies to increase the total length of the.

[0006]

The above-mentioned prior art cannot be said to give sufficient consideration to the performance improvement of the sub-passage type heating resistor type flow rate measuring device, and further shortens the sub-passage to reduce the influence of pulsation. There has been a problem that there is still dissatisfaction with respect to further promotion and further improvement of the fitting property to the intake pipe and the like.

[0007] For example, in the prior art disclosed in Japanese Patent Laid-Open No. 8-5427, the sub-passage itself must be made short,
The reduction of the output error caused by the pulsation influence has not been sufficiently taken into consideration, and also in the prior art disclosed in Japanese Patent Publication No. 4-75385, it cannot be said that the auxiliary passage itself is sufficiently short. It cannot be said that the attachability to the intake pipe or the like is sufficiently considered.

The auxiliary passage has a shape capable of reducing a flow rate measurement error caused by a pulsating flow generated by an internal combustion engine or the like, and measures an intake air flow rate in an intake pipe having a very small diameter found in a small displacement vehicle, or In order to obtain a heat generation resistance type flow rate measuring device capable of measuring the amount of secondary air and EGR, it is necessary to solve the following problems.

(1) The total length of the flow path is made longer than the distance between the entrance and exit of the sub passage seen in the main flow direction, and the height of the sub passage is reduced in the insertion direction of the sub passage. (2) The passage structure should prevent backflow. (3) To increase the air flow velocity inside the sub-passage and obtain a stable flow with no variations. (4) The projecting length of the structure should be suppressed even outside the main passage to achieve a low profile.

The present invention has been made in view of these problems, and an object thereof is to minimize the influence of intake pulsation and backflow, and to perform accurate measurement even in a main passage having a small diameter. An object of the present invention is to provide a heating resistance type flow rate measuring device that is obtained.

[0011]

The above object can be achieved by taking the following measures. (1) Open the sub passage in a plane perpendicular to the main flow direction of the main passage,
From the first flow path that is substantially parallel to the main flow direction, the second flow path that bypasses at the downstream end and guides the flow in the direction opposite to the main flow direction with the flow path that is substantially parallel to the first flow path, The bypass passage is provided with an outlet opening that joins in a direction substantially perpendicular to the main flow direction.

Further, the outlet opening is divided into two in the direction perpendicular to the insertion direction of the auxiliary passage into the intake pipe to be opened, or the cross-sectional shape of the first flow path in which the heating resistor is arranged is close to a semicircle. In addition, by taking measures such as a dimension that is short in the direction of inserting the auxiliary passage into the intake pipe and long in the direction perpendicular to the direction of inserting the auxiliary passage into the intake pipe, the height can be further reduced, and It is designed to improve wearability.

Furthermore, by arranging the inlet opening and the outlet opening so as to overlap each other in the insertion direction of the auxiliary passage, it is possible to reduce the flow and increase the area of the second flow passage and the outlet opening. did.

(2) The detour-type sub-passage member located downstream from the outlet opening has a step or a rounded bulge with respect to the detour-type sub-passage member located upstream from the outlet opening. With this structure, the backflow is less likely to enter from the outlet opening.

(3) Due to the contracted flow structure, the flow velocity in the heating resistor portion is increased, and the subsequent bypass flow passage has a flow passage cross-sectional area in the direction perpendicular to the flow inside the sub-passage. Alternatively, it is configured wider than the second channel. Further, a rectification guide was provided at the branch point toward the outlet opening.

(4) The electronic circuit and the circuit module are arranged outside the main passage substantially in parallel to the mainstream direction, and the sub passage is attached to the bottom of the circuit module to form the entire apparatus in a T-shape from the front.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The heating resistance type flow rate measuring device according to the present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 shows a first embodiment of the present invention, in which 1 is a heating resistor, 2 is a temperature sensitive resistor, and in this embodiment, these heating resistor 1 and temperature sensitive resistor 2 are It is attached to the terminal wire 3 and is electrically connected to the electronic circuit 4. Next, 5 is a detour type sub passage, and this detour type sub passage 5
Is attached to a case member 6 that also holds the terminal wire 3 and protects the electronic circuit 4.

Reference numeral 7 denotes an intake pipe which constitutes a main passage, and this intake pipe 7 constitutes a part of an intake air passage of the engine,
The air to be measured is circulated in the main flow direction indicated by the arrow 8, and the bypass sub passage 5 is
While being held by the case member 6, it is inserted into the intake pipe 7 through a hole provided in the side wall of the intake pipe 7 as illustrated.

In the bypass-type auxiliary passage 5, first, an inlet opening 1 is formed in a plane perpendicular to the main flow direction 8 in the intake pipe 7.
01 and the first flow path 1 extending from the inlet opening 101 substantially parallel to the mainstream direction 8 and having the heating resistor 1 installed therein.
02, and a bypass flow passage 103 that reverses the flow from the mainstream direction 8 to the opposite direction is formed therein.

Further, in the bypass sub-passage 5, the bypass flow passage 103 is parallel to the first flow passage 102 and the main flow direction 8
A second flow path 104 that extends in a direction substantially parallel to and guides the flow, and an outlet opening that is opened on both sides of the second flow path 104 in a direction substantially perpendicular to the main flow direction 8. The part 105 is formed.

Therefore, a part of the air that has flowed into the intake pipe 7 along the main flow direction 8 is fed from the inlet opening 101 to the arrow 8
-1 flows into the first flow path 102 and, via the bypass flow path 103, the second flow path 10 as shown by an arrow 8-2.
4 through the outlet openings 105 on both sides to flow out of the sub passage 5 as shown by an arrow 8-5 and join the air in the intake pipe 7.

As a result, the air flow in the first flow path 102 is averaged, and the influence of the pulsation of the flow rate in the intake pipe 7 on the measurement of the flow rate by the heating resistor 1 and the temperature sensitive resistor 2 is suppressed, It is possible to obtain accurate flow rate measurement. At this time, the longer the air flow passage by the sub-passage 5, the stronger the above-mentioned averaging action is obtained, but if it is longer, the device becomes larger.

However, according to this embodiment, the outlet opening 105 has the second flow path 10 as shown in FIG.
4 is open at right angles to the mainstream direction 8 and the air flowing through the second flow path 104 is split into both sides, so that the length of the outlet in each mainstream direction can be adjusted to the required outlet. It is possible to make it small while securing the area.
The second flow path 104 can be made long, and as a result, the auxiliary passage 5 having a sufficient length can be easily obtained without increasing the size of the device.

Further, in this embodiment, as shown in FIG. 2, the first flow passage 102 and the second flow passage 103 forming the sub passage 5 are perpendicular to the insertion direction of the sub passage 5, that is, the main flow direction 8. Since they are arranged along with each other, it is possible to sufficiently reduce the dimension of the intake pipe 7 in the inner diameter direction of the bypass sub-passage 5, which is shown as the flow passage installation range in the figure, that is, to achieve so-called low profile. As a result, it can be easily applied to a low-power internal combustion engine having a small-diameter intake air conduit.

This will be described more specifically with reference to FIGS. 16 and 17 and FIG. 3. First, FIG.
Is applied to the intake pipe 9 having a smaller diameter than the intake pipe 7, and FIG. 17 is an embodiment applied to the elliptical intake pipe 10.

In the first embodiment, the first channel 102
Direction from the second flow path 104 to the second flow path 104, that is, the bypass flow path 10
3 is the same as the insertion direction of the auxiliary passage 5 into the intake pipe 7 (from top to bottom in FIG. 3), as is clear from the AA cross-sectional view of FIG. 7
It is branched into two directions, that is, a direction perpendicular to the main flow direction 8 inside and a direction perpendicular to the insertion direction of the sub passage 5 as well.

Here, the outlet opening 105 is opened at a right angle to the insertion direction of the sub passage 5 into the intake pipe 7 because the sub passage 5 has a small diameter shown in FIGS. 16 and 17. When the measurement is performed by inserting into various intake pipes such as the intake pipe 9 or the elliptical intake pipe 10, the clearance W from the outlet opening 105 to the wall surface of the intake pipe is different from the clearance H in the auxiliary passage insertion direction. , So that it can be taken large.

That is, according to this embodiment, the relation between the clearance W and the clearance H can easily be W> H.
As a result, the interference between the air flowing out from the outlet opening 105 and the inner wall surface of the intake pipe (9 or 10) can be suppressed to a sufficiently small level. Also, there is no fear that the flow velocity of the air flowing inside the sub passage will decrease, and good measurement accuracy can be maintained at all times.

As described above, according to the first embodiment of the present invention, the height of the auxiliary passage can be sufficiently reduced,
It can be easily applied to the intake pipe with an extremely small diameter found in small displacement engine cars, etc., and enables highly accurate intake flow rate measurement.

Next, according to the bypass type sub-passage structure according to the first embodiment, the flow rate measurement error caused by the engine pulsating flow can be further reduced. The measurement error due to the influence of the pulsation will be described.

The air flowing through the intake pipe of the engine becomes a pulsating flow as the intake valve of the engine is opened and closed. The magnitude of the pulsation at this time depends on the throttle valve of the engine.
When the opening of the (throttle valve) is small, it is relatively small, and when the opening of the throttle valve is large, it becomes large, and also when the intake flow rate increases. When the pulsation becomes large to some extent, a negative error occurs due to the non-linear characteristic of the flow rate measurement by the heating resistor and the response delay characteristic of the heating resistor itself.

When the pulsation amplitude is further increased, a backflow occurs in the intake pipe. However, it is difficult to detect the flow direction by the heating resistor because of its structure. Since the forward flow and the reverse flow are simply detected as the flow velocity, when the reverse flow occurs, the heating resistor also detects the reverse flow as the flow velocity, resulting in a plus error.

These positive and negative output errors further reduce the intake pulsation that reaches the inside of the sub passage, and even if a back flow occurs, the back flow does not enter the inside of the sub passage. Can be reduced by.

This can be achieved by increasing the inertia of the air flow flowing inside the sub-passage, and more specifically, with respect to the distance between the entrance and exit of the sub-passage viewed in the main flow direction, It is most effective to make the total length long.

That is, it can be said that the bypass type bypass passage structure according to the first embodiment of the present invention described above is an ideal passage structure for reducing the height of the bypass passage and reducing the flow rate measurement error due to the influence of pulsating flow.

Next, regarding the second embodiment of the present invention,
This will be described with reference to FIG. In the embodiment shown in FIG. 4, the inlet opening 101 and the outlet opening 105 are overlaid as shown in the drawing in the insertion direction of the auxiliary passage 5 into the intake pipe 7, that is, in the direction perpendicular to the main flow direction 8. They are arranged so as to be wrapped, and other configurations are the same as those of the embodiment of FIG. 1, and therefore, the description of the intake pipe 7 is omitted.

In the embodiment of FIG. 4, while the height of the sub passage 5 is reduced, the flow is further throttled in the flow passage portion where the heating resistor 1 is present, so that the air flow velocity is increased in this portion. The variation of the detection signal of the air flow rate is reduced.

FIG. 5 shows a concrete structure of the bypass type auxiliary passage 5 in the second embodiment, in which B is shown.
As is clear from the -B cross-sectional view, the cross-sectional dimensions of the first flow path 102 in which the heating resistor 1 is arranged are the dimension H in the sub-passage insertion direction indicated by the arrow and the dimension W in the direction orthogonal thereto. , W> H, and the cross section of the first flow path 102 is formed in a shape close to a semicircle, whereby the heat generating resistor 1 is arranged in a portion. The diaphragm effect is further increased.

Next, FIG. 6 shows a third embodiment of the present invention. In this embodiment, the bypass passage 103 is set to have the highest height with respect to the height of each passage forming the sub passage 5. It is the one. Note that the intake pipe 7 is also omitted in FIG. 6.

In the case of the bypass sub-passage system, the bypass portion has the highest ventilation resistance in the sub-passage 5. Therefore,
In the embodiment of FIG. 6, the height of the bypass flow passage 103 is made larger than that of the other flow passages, whereby the ventilation resistance of the entire sub passage 5 is reduced and the air flow velocity is increased. The variation is further suppressed.

Next, FIG. 7 shows a fourth embodiment of the present invention.
In this embodiment, as is clear from the sectional view taken along the line CC, the flow straightening guide 106 for smoothly branching the flow from the second flow path 104 to the outlet opening 105 is provided.
The rectification guide 106 is provided with the second flow path 1
The air flow that has passed through 04 is prevented from colliding vertically with the wall surface, and works so that there is no high pressure portion near the outlet opening 105.

If there is a high pressure portion in the sub passage 5, the flow in the vicinity of the outlet opening 105 becomes poor and the flow velocity in the sub passage 5 as a whole declines. The decrease is suppressed, and as a result, the sub passage 5
Since the velocity of the air flowing through the inside is increased, variations in the air flow rate signal, that is, output noise is reduced, and accurate flow rate detection can be obtained.

Next, FIG. 8 is a front view showing a fifth embodiment of the present invention. In the embodiment of FIG. 8, an electronic circuit 4 (not shown) is installed, a drive circuit module 60 for protecting the electronic circuit 4 is arranged outside the intake pipe 7, and further, with respect to the main flow direction of the intake pipe 7. Drive circuit module 6
It is arranged so that 0 is almost parallel, that is, outside the intake pipe 7 to be a flat horizontal type.

Then, on the bottom surface of the drive circuit module 60, it is set at a predetermined position in the intake pipe 7,
A detour type auxiliary passage 5 is attached, whereby the entire device is configured in a direction perpendicular to the cross section of the intake pipe 7, that is, a T-shape when viewed from the front.

Therefore, according to the embodiment of FIG. 8, it is possible to reduce the height of the flow rate measuring device not only on the inside of the intake pipe 7 but also on the outside thereof. Even if the space that can be secured is small, such as when installing the, the degree of freedom of the mounting position can be increased.

Next, FIG. 9 shows a sixth embodiment of the present invention, as shown in the sectional view taken along the line DD, in this embodiment, on both sides of the outer surface of the auxiliary passage 5, Outlet opening 1
The bulge portions 108 and 109 are located on the downstream side of 05.
Is provided.

These bulging portions 108 and 109 are specifically formed in a shape that bulges downstream from a position directly downstream of the outlet opening 105 with a step, whereby, for example, an intake pipe of an internal combustion engine. Even if a backflow occurs, the backflow is prevented from entering the sub-passage 5. As a result, according to this embodiment, it is possible to minimize the error included in the air flow rate signal when the backflow occurs.

Next, FIG. 10 shows the seventh embodiment of the present invention, and the lower side view is a plan view of the sub passage 5 as viewed from the lower side with respect to the upper side sectional view. Then, the circular broken line represents the insertion hole 11 of the auxiliary passage 5 formed in the intake pipe 7.

In the embodiment of FIG. 10, the outer shape of the bypass sub-passage 5 is such that, when viewed from the bottom surface, the upstream end surface 5A and the downstream end surface 5B are rounded cylindrical surfaces. The shape of each of the end faces 5A and 5B is characterized in that the end faces 5A and 5B are formed in conformity with the insertion hole 11 at that time.

As a result, according to the embodiment of FIG. 10, the length of the bypass sub-passage formed by the sub-passage 5 is equal to that of each end face 5A,
By the bulge of 5B, the size restricted by the insertion hole 11 can be secured as long as possible, so that the flow rate measurement error due to the influence of the pulsating flow can be reduced by that amount, and the end faces 5A, 5
The bulge of B acts to make the shape of the sub-passage 5 closer to a streamline with respect to the main flow in the intake pipe 7, so that the pressure loss in the intake system can be reduced.

Next, FIG. 11 shows an eighth embodiment of the present invention in which the sub passage 5 is connected to the flow path forming member 201 and the back plate 2.
It is composed of two parts 02. When it is attempted to mold the detour-type sub-passage 5 with a resin mold, there may be a portion where the die cannot be removed.

Therefore, in the embodiment of FIG. 11, the sub-passage 5 is connected to the flow path forming member 201 and the back plate 202.
It consisted of individual parts. In addition, as a method of constructing the bypass-type auxiliary passage by these two parts, the second flow path 104
There is a method of making the bottom surface of the above as a separate component, a method of dividing the sub passage 5 from the center of the front surface, and the like.

FIG. 12 is an enlarged view of the portion E in the embodiment of FIG. 11. When the member to be inserted into the intake system such as the sub passage 5 is composed of a plurality of parts, the parts are securely fixed. If you do not do this, in the unlikely event that a part falls off,
It may get caught in the throttle valve and cause a serious accident.

Therefore, in this embodiment, as shown in FIG. 12, a spherical convex portion 203 is provided on the back plate 202, and the convex portion 20 is provided on the flow path forming member 201 side.
A recessed portion or hole 204 is provided so that the recessed portion 3 can be positioned at a regular position when the flow path forming member 201 is inserted.
The back plate 202 is positioned and fixedly attached by a push-fit mechanism in which the back plate 202 is fitted using the elasticity of the resin.

Further, in this embodiment, as is apparent from FIG. 12, the back plate 202 and the flow path forming member 2 are provided.
The groove 205 is provided in the fitting portion of No. 01, and the adhesive 206 is applied inside the groove 205 in advance at the time of fitting, and the adhesive 206 is attached to the back plate 202 when the back plate 202 is attached.
A double system fixing method is also provided in which the adhesive fixing by the method is also used.

Therefore, according to the embodiment shown in FIGS. 11 and 12, it is possible to reliably prevent the back plate 202 from falling off and prevent air leakage inside and outside the sub passage 5. it can.

Next, FIG. 13 shows a ninth embodiment of the present invention, which is different from the embodiments described with reference to FIGS. 11 and 12.
A corner rectifying member 207 is formed on the inner surface of the back plate 202.
Is only provided. This corner straightening member 20
Reference numeral 7 is a member for forming the curved portion of the bypass flow passage 103 into a shape that requires less ventilation resistance, that is, a smooth curved surface without corners, and is integrated with the back plate 202. The inner surface of the back plate 202 may be curved.

In the embodiment shown in FIG. 13, since the corner rectifying member 207 is provided, the ventilation resistance in the bypass passage 103 where the ventilation resistance increases in the sub-passage 5 is reduced. It is possible to suppress a decrease in flow velocity as a whole.

Next, FIG. 14 shows a tenth embodiment of the present invention, in which a flange portion 301 is provided at an end portion on the inner surface side of the intake pipe 7 of a hole for inserting the auxiliary passage 5 provided in the intake pipe 7. Is provided, and the other structure is the same as that of the embodiment of FIG.

This flange portion 301 is used for the flow path forming member 2
01 and the back plate 202 are combined to prevent the bypass-type sub passage 5 from dropping into the intake pipe 7. Just like the back plate 202,
If the sub passage 5 falls off, there is a great possibility that it may lead to a serious accident, and therefore a measure to prevent the sub passage itself from falling off is indispensable. However, according to the embodiment of FIG.
1 makes it possible to prevent the sub passage 5 from falling off easily and reliably.

Next, FIG. 15 shows an embodiment in which the flow rate measuring device according to the present invention is applied to an electronic fuel injection type internal combustion engine. In FIG. The air 52 is supplied to the suction duct 53,
Throttle body 54 and injector (fuel injection valve)
It is sucked into the cylinder 57 of the engine through an intake manifold 56 having 55. On the other hand, the gas 58 generated in the cylinder 57 of the engine is discharged into the atmosphere through the exhaust manifold 59.

Between the air cleaner 51 and the suction duct 53, the heat generation resistance type flow rate measuring device according to the above embodiment is provided, and the air flow rate signal output from the drive circuit module 60 and the intake air temperature sensor 61 are output. Intake air temperature signal, throttle valve angle signal output from throttle angle sensor 62, oxygen concentration signal output from oximeter 63 provided in exhaust manifold 59, engine speed output from engine tachometer 64 Signals, intake air pressure signals input from various sensors (not shown), and the like are input to the control unit 65.

Therefore, the control unit 65 inputs these signals and sequentially calculates them to obtain the optimum fuel injection amount and the idle air control valve opening degree, and using the values, the injector 55 and the idle control valve 66. To control.

At this time, according to the heat generation resistance type flow rate measuring device according to the above-mentioned embodiment, a highly accurate intake air flow rate signal which is not affected by the pulsation of the engine intake air can be obtained, so that the control of the fuel amount to the engine can always be performed accurately. Can be done
It is possible to sufficiently promote purification of exhaust gas and energy saving. Further, at this time, according to the heat generation resistance type flow rate measuring device according to the above-described embodiment, it is possible to obtain an effect that it can be easily applied to a small engine.

[0065]

According to the present invention, since the bypass type bypass passage can be reduced in height, that is, can be downsized, the bypass passage can be easily inserted to a position exposed to the mainstream air even in a main passage having a considerably small diameter. It can be arranged and can always measure the flow rate with high accuracy.

As a result, according to the present invention, the intake air amount of the engine can be measured by applying it to a small-diameter intake pipe or an elliptical intake pipe found in a small displacement automobile or the like. It can be applied to the measurement of the flow rate of the secondary air and the flow rate of the EGR air, and the engine can be controlled with higher accuracy.

Further, according to the present invention, the height of the circuit module can be reduced and the overall size of the device can be reduced even outside the main passage, so that the flow rate can be easily measured even when only a narrow space can be prepared. The device can be installed, and as a result, the application is further expanded, and a high degree of freedom of installation can be obtained even in the inside of the engine room where the device is overcrowded.

Further, according to the present invention, since a highly accurate flow rate measuring device having a bypass sub passage can be easily obtained, it is possible to prevent the influence of intake pulsation and backflow generated by an internal combustion engine. As a result, it is possible to reduce the flow rate measurement error due to these, and therefore it is not necessary to correct the air flow rate signal having an error in the drive circuit module or the control unit, which further reduces the system cost of the intake system. It can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a heating resistance type flow rate measuring device according to the present invention.

FIG. 2 is a sectional view showing details of the first embodiment of the present invention.

FIG. 3 is a cross-sectional view taken along the line AA showing a specific passage structure according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a second embodiment of the present invention.

FIG. 5 is a cross-sectional view taken along line BB showing a specific passage structure in the second embodiment of the present invention.

FIG. 6 is a sectional view showing a third embodiment of the present invention.

FIG. 7 is a sectional view taken along line C-C showing a specific configuration of a passage according to a fourth embodiment of the present invention.

FIG. 8 is a front view showing a fifth embodiment of the present invention.

FIG. 9 is a cross-sectional view taken along line D-D showing a specific configuration of a bypass passage according to a sixth embodiment of the present invention.

FIG. 10 is a sectional view and a plan view showing a seventh embodiment of the present invention.

FIG. 11 is a sectional view showing an eighth embodiment of the present invention.

FIG. 12 is an enlarged view of a portion E in the eighth embodiment of the present invention.

FIG. 13 is a sectional view showing a ninth embodiment of the present invention.

FIG. 14 is a sectional view showing a tenth embodiment of the present invention.

FIG. 15 is an explanatory diagram showing an embodiment of an internal combustion engine control device using the heating resistor type flow rate measuring device according to the present invention.

FIG. 16 is a front view showing an example of a mounted state of the present invention.

FIG. 17 is a front view showing another example of the mounted state of the present invention.

[Explanation of symbols]

1 heating resistor 2 Temperature-sensitive resistor 3 terminals 4 electric circuits 5 Detour-type vice passage 5A, 5B Rounded end face 6 case members 7 main passage 8 mainstream direction 9 Small diameter intake pipe 10 Elliptical intake pipe 11 Sub passage insertion hole 51 air cleaner 52 Intake air 53 Intake duct 54 Throttle body 55 injector 56 intake manifold 57 engine cylinder 58 gas 59 Exhaust manifold 60 drive circuit module 61 Intake temperature sensor 62 Throttle angle sensor 63 oxygen meter 64 tachometer 65 control unit 66 Idle air control valve 101 entrance opening 102 First flow path 103 Detour flow path 104 Second channel 105 Exit opening 106 Rectification guide 108, 109 bulge 201 Flow path component 202 back plate 203 spherical projection 204 through hole 205 Adhesive groove 206 adhesive 207 Corner straightening member 301 Flange member

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinya Igarashi 2477 Takaba, Hitachinaka City, Ibaraki Hitachi Car Engineering Co., Ltd. (56) Reference JP-A-9-329472 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01F 1/68 G01P 5/12

Claims (20)

(57) [Claims] 1. A heating resistor for detecting the flow rate of a fluid, an electronic circuit electrically connected to the heating resistor for outputting a signal according to the flow rate of the fluid, and a case for internally protecting the electronic circuit. A sub-passage having at least one bent portion is fixed to a circuit module integrated with a member so that the heating resistor is located inside the sub-passage, and the sub-passage is provided in the main passage which is a fluid passage. Is located and the electronic circuit is mounted so that the electronic circuit is located outside the main passage, the auxiliary passage is opened in a surface perpendicular to the main flow direction of the main passage, and is substantially in the main flow direction. A parallel first flow path, a second flow path that detours at its downstream end and guides the flow in a direction opposite to the main flow direction in a flow path that is substantially parallel to the first flow path, and from the second flow path in the main flow direction. An outlet opening that joins the vertical direction A bypass type auxiliary passage having a section, a substantially the first flow path and the second flow path the sum degree of length to the insertion direction of the auxiliary passage length for the sub-passage direction of insertion into the main passage, before A heating resistance type flow rate measuring device characterized in that the length of the auxiliary passage is kept short. 2. The outlet of the sub-passage according to claim 1, wherein the outlet of the sub-passage is opened in a plane parallel to the insertion direction of the sub-passage, and the sub-passage forms an upper end of the inlet opening with respect to the insertion direction of the sub-passage. A heating resistance type flow rate measuring device, characterized in that it is formed between the lower end of the outlet opening. 3. The outlet opening according to claim 1, wherein the outlet opening is branched at least in two or more directions after detouring from the first flow path to the second flow path, and at least the outlet opening is formed. A heating resistance type flow rate measuring device characterized by being arranged in two or more places. 4. The inlet opening and the outlet opening of the bypass type bypass passage according to any one of claims 1 to 3, wherein the inlet opening portion and the outlet opening portion are overlapped with each other in a direction in which the sub passage is inserted into the main passage. Heat resistance type flow rate measuring device characterized in that it is arranged as. 5. The cross-sectional shape according to any one of claims 1 to 4, wherein the cross section of the first flow path or the second flow path in which the heating resistor is arranged or the flow path perpendicular to the flow direction is A heating resistance type flow rate measuring device characterized in that it is configured to be short in a direction of inserting the auxiliary passage into the main passage and long in a direction perpendicular to the direction of inserting the auxiliary passage into the main passage. 6. The cross-sectional area of each flow path constituting the sub-passage according to claim 1, wherein the cross-sectional area of each flow path is greater than that of the first flow path and the second flow path with respect to the main flow direction. The heat generating resistance type flow rate measuring device is characterized in that the bypass passage that guides the flow in the vertical direction is wider. 7. The heat generation resistance type flow rate measuring device according to claim 1, wherein a bypass direction of the sub passage is a inserting direction of the sub passage into the main passage. . 8. The flow path of the heating resistor portion according to any one of claims 1 to 7, wherein the first flow path of the sub-passage changes a flow velocity of the heating resistor portion from the inlet opening toward the heating resistor installation portion. A heating resistance type flow rate measuring device characterized by having a contracted flow structure for increasing the flow rate. 9. The fluid flow guide according to claim 1, wherein the fluid is smoothly guided from the inside of the second flow passage to the outlet opening near the outlet opening of the second flow passage. An exothermic resistance type flow rate measuring device, which is provided with a rectification guide. 10. The heating member according to claim 8, wherein a lower end surface of the inlet opening is tapered toward a downstream side of the first flow path, and the heating resistor portion of the first flow path is a narrowest part of the flow path. Alternatively, the heat generation resistance type flow rate measuring device is characterized in that the flow rate measuring device is configured to have a contracted flow structure such that it has a maximum flow velocity portion in the flow path. 11. The outlet according to claim 9, wherein the rectification guide divides the second flow path into two parts in parallel with a direction of inserting the sub-path into the main path, that is, in a vertical direction, and opens at two left and right sides thereof. A heating resistance type flow rate measuring device characterized in that it smoothly guides the fluid toward the opening. 12. The flow path cross-sectional shape perpendicular to the flow direction in the contracting portion of the first flow path according to claim 10, wherein the flow path cross-sectional shape is short in the sub-passage insertion direction into the main passage,
A heat generating resistance type flow rate measuring device characterized in that it is long in the direction perpendicular to the direction, and the second flow path has a flow path width in the direction perpendicular to the sub-passage insertion direction into the main passage. . 13. The method according to any one of claims 1 to 12.
In the paragraph, the electronic circuit and the circuit module for internally protecting the electronic circuit are placed outside the main passage and in a position substantially parallel to the main flow direction of the main passage, and on the bottom surface side of the circuit module. A heating resistance type flow rate measuring device characterized in that the detour type auxiliary passage is attached so as to be located in the main passage, so that the entire device is formed in a T shape from the front. 14. The method according to any one of claims 1 to 13.
In the paragraph, the constituent member of the bypass-type auxiliary passage located on the downstream side of the outlet opening has a step or a rounded bulge with respect to the bypass-type auxiliary passage constituent member located on the upstream side of the outlet opening. An exothermic resistance type flow rate measuring device characterized by having. 15. The method according to any one of claims 1 to 14.
In the paragraph (1), the outer shape of the detour-type sub-passage is formed in a streamlined shape with roundness along the sub-passage insertion hole formed in the main passage at the most upstream and the most downstream end faces in the main passage. A heating resistance type flow rate measuring device characterized in that 16. The method according to any one of claims 1 to 15.
Item 3. A heating resistance type flow rate measuring device, characterized in that the detour-type sub-passage is composed of at least two or more resin mold parts. 17. The push-fit mechanism according to claim 16, wherein the bypass-type sub-passage is composed of two parts, a flow-passage forming member and a passage cover, and uses elasticity of resin to prevent the passage cover from falling off. 2 by adhesive
A heating resistance type flow measuring device characterized in that a heavy fixing method is used. 18. The corner rectifying member according to claim 17, wherein the passage cover is formed to have a smooth curved flow line of the bypass passage connecting from the first flow passage to the second flow passage. An exothermic resistance type flow rate measuring device characterized by being integrally molded. 19. The method according to any one of claims 1 to 18.
The heating resistance type flow rate measuring device according to the item 1, wherein a mechanism for preventing the flow path constituting member from falling is provided on the main passage side. 20. An internal combustion engine control device, characterized in that the internal combustion engine is controlled using any of the bypass sub-passages according to any one of claims 1 to 19.