JPH08278179A - Exothermic resistance type air flow measuring device - Google Patents

Abstract

PURPOSE: To improve measuring accuracy in such a pulsating flow-down in association with a counter-flow in the case of actual car installation by using a throttle or the like in a detection pipe, and altering a flow velocity distribution in both forward and reverse directions. CONSTITUTION: A detection duct 3 is integrally formed in a body 1 via a bridge part 38 like bridgeingly traversing the inner part, and a heating resistor 5 measuring intake air flow rate and a temperature sensing resistor 6 detecting intake air temperature both are disposed in an inner part of the duct 3. As to size of the duct 3, an effective sectional area of this duct 3 is almost 20% or over that of a main air passage, and a throttle 8 with a form of almost 1/4 circle is formed in an inlet of the duct 3 over the whole circumference of the detection duct. In the case where the throttle 8 is installed upstream the detection duct, inertia force having a flow in the forward direction is strong on the inside of the duct 3, but this inertia force other than the duct 3 becomes weakened the other way. Accordingly, since the resistor 5 compliantly detects the flow rate by means of flow velocity distribution, it becomes hard to detect the counter flow, consequently an error due to the counter flow is reducible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air flow meter for measuring the intake air flow rate of an internal combustion engine, and more particularly to a heat generation resistance type air flow meter suitable for measuring the air flow rate of air taken into an automobile engine.

[0002]

2. Description of the Related Art As means for improving the measurement accuracy of a heating resistor type air flow meter used in an internal combustion engine under conditions such as backflow under pulsating flow, there is disclosed in Japanese Patent Laid-Open No. 2-1518.
A known passage structure having an L-shaped detection tube as shown in FIG. That is, by providing a wall for the flow in the opposite direction, the passage structure is provided so that the heat generating resistor is not directly hit by the reverse flow. However, in this structure, since the detection tube is bent in an L-shape, the effective cross-sectional area of the main passage is narrowed, resulting in an increase in pressure loss and variations in detection accuracy in the low flow rate range due to a decrease in the flow velocity of the heating resistor arrangement portion. Is seen as an issue.

As a structure having a throttle in a passage shown in an embodiment of the present invention, a structure as disclosed in Japanese Patent Laid-Open No. 1-120220 is known. In this structure, the restrictor is annularly placed on the wall surface of the main passage, and a heating resistor is arranged immediately downstream of the restrictor in a detection tube having a short distance in the mainstream direction.

Further, in JP-A-63-210727, a structure having a diaphragm in the detection tube is known. This structure is a structure in which the area ratio of the effective sectional area of the detection pipe to the effective sectional area of the main passage forming the intake conduit is very small. This is because the inner diameter of the detection tube must be reduced in order to keep the flow velocity in the detection tube in a laminar state. The Reynolds number must be 2300 or less in order to keep the flow velocity in the pipeline laminar.

Reynolds number = V × D / ν V = average flow velocity in pipe (m / s) D = pipe diameter (m) ν = kinematic viscosity coefficient (m2 / s) In the case of air, about 15 at 15 ° C. X10 ^ (-6) Generally, considering the stability of the heat ray output, the flow velocity of the heat ray is required to be at least 3 to 4 (m / s), and about 10 times that is required in the high engine speed region. . Applying this value to the above formula, the inner diameter of the detection tube is 10 mm at maximum.
Must be: The main air passage outside the detection pipe that constitutes a part of the intake pipe needs to have an effective area equal to or more than 40 mm in inner diameter at least, and the ratio of the effective area of the detection pipe to the effective area of the main air passage is very small. It will be.

[0006]

Generally, it is impossible for the heating resistor used in the above-mentioned prior art to measure the flow direction separately. Therefore, for example, as shown in FIG. 3, when the throttle valve is gradually opened and the boost pressure is changed to plot the average output of the heating resistor type air flow meter as shown in FIG. 3, the actual output is obtained after a certain boost pressure. A phenomenon occurs in which the object is lifted up (called the bounce phenomenon). This is because the pulsation amplitude of the heating resistor type air flow meter gradually increases as shown in FIG. 4, and a backflow occurs after point A. When the backflow occurs, the heating resistor cannot determine the flow direction as described above, and therefore the forward flow and the backflow are similarly detected, so that the average output jumps. It is known that this phenomenon is particularly likely to occur in an engine having four or less cylinders in a relatively low rotation speed range of 1000 to 2000 rpm, and is unlikely to occur in an engine having more cylinders.

An object of the present invention is to improve the measurement accuracy under the pulsating flow accompanied by backflow when the vehicle is mounted, which is one of the biggest problems of the heating resistor type air flow rate measuring device. Furthermore, by not simplifying the passage structure, by simplifying it, the accuracy of variation is improved, the cost is reduced, and
It is an object of the present invention to provide a heating resistor type air flow rate measuring device having excellent handleability.

[0008]

[Means for Solving the Problems] In order to improve the measurement accuracy in a pulsating flow accompanied by a backflow when an actual vehicle is mounted, the flow velocity distribution in the forward and reverse directions is changed by using a throttle or the like in the detection tube. I chose That is, the passage structure is forcibly created by utilizing the inertial force of the forward air flow to forcibly create the flow velocity distribution in which the backflow is less likely to hit the heating resistor.

Further, since it is possible to reduce the error due to the backflow without complicating the passage structure, it is possible to improve the detection variation accuracy of the heating resistor in the low flow rate (low flow velocity) area without increasing the pressure loss. It is possible to provide a heating resistor type air flow rate measuring device at a low cost.

Further, the handling can be improved by integrating the circuit portion and the detection pipe portion with a hole provided in a part of the intake pipe and detachably fixed to the main air passage. .

[0011]

By providing a throttle or the like upstream of the detection tube, the flow velocity at the portion where the heating resistor is installed becomes faster than the average flow velocity in the main air passage when air flows in the forward direction. In other words, when air flows in the forward direction, the flow velocity is high near the heating resistor arrangement,
The flow velocity distribution becomes slower at other positions. on the other hand,
Under the condition that the backflow of the internal combustion engine is likely to occur, for example, in a 4-cylinder car, the pulsation cycle at 1000 rpm is about 33 Hz, and the presence or absence of the backflow is observed about 30 times per second. The air flow is pulsating at a considerably high speed, and the inertial force of the flow is different at the position where the flow velocity is different. That is, at the position where the flow velocity is fast,
The force of inertia is strong, and conversely, the force of inertia becomes weak at the position where the flow velocity is slow.

Further, under such conditions, if the flow direction changes instantaneously and a backflow occurs, it is difficult to obtain the backflow at the position where the forward inertial force is strong, and the position where the forward inertial force is weak. Shows a flow velocity distribution that facilitates the reverse flow. That is, when the flow direction changes instantaneously, it is difficult to obtain a backflow at the installation position of the heating resistor, and it becomes easy to obtain a backflow at other locations.

The above effect will be described with reference to FIG. 5 by taking as an example a case where a throttle is used on the upstream side of the detection tube as a structural means for temporarily increasing the upstream side of the heating resistor installation position. It is generally known that the flow velocity distribution in a pipe shows a parabolic flow velocity distribution under a steady flow, but has a relatively flat flow velocity distribution under a pulsating flow.

First, the upper part of FIG. 5 shows the case where no throttle is provided upstream of the detection tube. The forward air flow 10 has a larger absolute flow rate than the reverse air flow 13. Here, the flow velocity is represented by the length of the arrow vector of the flow velocity distribution shown in the figure, and the flow rate is represented by the area of the flow velocity distribution. When the restriction is not provided, the forward flow has a relatively flat velocity distribution as described above. Therefore, even if the reverse flow changes instantaneously, it shows a relatively flat velocity distribution. That is, in such a case, the heat generating resistor has a passage structure in which it is easy to take a reverse flow without depending on the installation position.

On the other hand, when the diaphragm is provided upstream of the detection tube, the result shown in the lower part of FIG. 5 is obtained. In the detection tube, the flow rate is the same as when there is no throttling, but since the air is taken in from a wide range due to the throttling, the flow rate in the detection tube shows a faster flow rate than the average flow rate, and in other places it is close to the average flow rate, It becomes slower than the average flow velocity. Therefore, the inertial force of the forward flow is strong inside the detection tube, and the inertial force is weak except for the detection tube. Therefore, when the flow direction changes instantaneously and a backflow occurs, it is difficult to take a backflow at a position where the inertial force of the forward flow is strong, and it is easy to take a backflow where the inertial force of the forward flow is weak. The distribution is shown.

[0016]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 is a cross section of a heating resistance type air flow meter showing an embodiment of the present invention, and FIG. 2 is an external view seen from the upstream (left side) thereof.

A detection conduit 3 is integrally formed in a body 1 of a heat resistance type air flow meter which constitutes a main air passage 2 which is a part of an intake system, via a bridge portion 38 which crosses the inside of the body 1 in a bridging manner. ing. A heating resistor 5 for measuring the intake air flow rate and a temperature sensitive resistor 6 for detecting the intake air temperature are arranged inside the detection pipe line 3 and electrically connected to a support 7 made of a conductive member. , And is electrically connected to a module 4 having a drive circuit built in outside the body 1. The body 1, the bridge portion 38, the rectifying body 9 for rectifying the turbulence of the air, and the detection conduit 3 are integrally configured, and the heating resistor 5, the temperature-sensitive resistor 6, the conductive support body are provided. 7 includes a drive circuit with a connector 12 for interfacing with the outside through a non-conductive member 14.
The integrated module 4 is mechanically fixed to the body 1 using screws 11. At the entrance of the detection pipe line 3, a diaphragm 8 having a shape of approximately 1/4 circle is formed around the entire circumference of the detection pipe line, and the downstream side thereof has a structure having a step. Here, although the shape of the detection conduit 3 is circular in this embodiment, it may be rectangular or other square. The flow of the intake air is a flow from the left to the right in the drawing in the forward direction. That is, the forward flow (from the air cleaner to the engine) is shown in FIG. 10, and the reverse flow (from the engine to the air cleaner) is shown in FIG.

The characteristic shown in FIG. 3 is a graph showing the average output of the heating resistor type air flow meter by gradually opening the throttle valve while keeping the rotation speed constant and changing the boost pressure. This is a phenomenon called the bounce-up phenomenon as described above, which is caused by the reverse flow of the engine.

This phenomenon is particularly likely to occur in a relatively low speed region of 3000 rpm or less in an engine having four cylinders or less,
This is a phenomenon that affects engine matching in this area. This phenomenon shows that when the throttle valve is relatively closed (left side of the graph), the pulsation amplitude in the intake pipe is small, but as the throttle valve is gradually opened, the pulsation amplitude increases, and at point A, the pulsation amplitude averages. This occurs because the flow velocity fluctuates around the value to the zero point, and at point B where the throttle valve is fully opened, there is a pulsation amplitude accompanied by backflow.

However, in this phenomenon, if the heating resistor detects the direction and outputs the reverse flow at the point B as a minus line as shown by the dotted line in the figure, the average output at the point A does not jump up, but the heating resistor is structurally different. Since it is difficult to measure the flow direction separately, when a backflow occurs in the intake pipe, the heating resistor measures the backflow in addition to the forward flow and double counts, so the output is against the actual output. It jumps up.

FIG. 5 is a view showing the flow velocity distribution in the main air passage 2 with and without the throttle 8 provided at the inlet of the detection pipe 4 which is a feature of the present invention shown in FIG. The effect of reducing the backflow effect of the present invention will be described with reference to this figure.

First, the upper part of FIG. 5 shows the case where no throttle is provided upstream of the detection pipe. The forward air flow 10 has a larger absolute flow rate than the reverse air flow 13. Here, the flow velocity is represented by the length of the arrow vector of the flow velocity distribution shown in the figure, and the flow rate is represented by the area of the flow velocity distribution. When no restriction is provided, the forward flow shows a relatively flat velocity distribution as described above (generally, the velocity distribution in the pipeline shows a parabolic velocity distribution under steady flow, but under pulsating flow). Is known to exhibit a relatively flat velocity distribution). Therefore, even if the reverse flow changes instantaneously, it shows a relatively flat velocity distribution. That is, in such a case, the heat generating resistor has a passage structure in which it is easy to take a reverse flow regardless of the installation position.

On the other hand, when a throttle is provided upstream of the detection pipe, the result shown in the lower part of FIG. 5 is obtained. In the detection pipeline, the flow rate is the same as when there is no throttling, but since the air is taken in from a wide range due to the throttling, the flow velocity in the detection pipeline is faster than the average flow velocity, and in other places, the average flow velocity. Close to or slower than the average flow velocity. That is, the inertial force of the forward flow is strong inside the detection conduit, and the inertial force is weak outside the detection conduit. Therefore, when the flow direction changes instantaneously and a backflow occurs, it is difficult to take a backflow at a position where the inertial force of the forward flow is strong, and it is easy to take a backflow where the inertial force of the forward flow is weak. The distribution is shown. For this reason, since the heating resistor can detect the flow rate in a straightforward manner according to the flow velocity distribution, it is difficult to detect the backflow. Therefore, as a result, the heating resistor type air flow measuring device can reduce the error due to the backflow, and can improve the measurement accuracy under the pulsating flow accompanied by the backflow.

In the above-mentioned structure in which the throttle is provided upstream of the detection pipe, the experimental result of the author shows that the size of the detection pipe is larger than the effective sectional area of the main air passage. When the cross-sectional area is approximately 20% or more, and the size of the throttle in the detection conduit is approximately 80% or less of the passage effective cross-sectional area of the throttling resistor, the error due to backflow is reduced. The effect was recognized, and the reduction effect was not recognized outside this range (main air passage diameter = 60 mm, detection pipe diameter =
30 mm, squeeze portion diameter = 26 mm). This is the flow rate of the main air passage, put a flow rate that is in the detection pipe,
This is because the effect of changing the flow velocity distribution cannot be obtained without narrowing down.

FIG. 6 is a cross-sectional view of a heating resistance type air flow meter showing another embodiment of the present invention. In FIG. 6, a flat portion 15 is provided at the entrance of the detection conduit instead of the diaphragm, and the other configurations are the same as in FIG. FIG. 7 is a diagram showing a flow state when a forward flow flows in the detection conduit of FIG. When a forward flow flows through the detection pipe line 3, pressure is applied to the flat surface portion 15,
A separation vortex occurs downstream of that. Therefore, the effective area of the passage is temporarily narrowed at the inlet of the detection pipe, the flow velocity at the inlet is increased, the flow velocity at the heating resistor installation portion downstream is also increased, and the force of inertia of forward flow can be strengthened. . Therefore, an effect similar to that of the throttle 8 provided at the entrance of the detection conduit shown in FIG. 1 can be obtained, and the flow velocity distribution as shown in the lower diagram of FIG. 5 can be obtained, and the heating resistor type air flow rate measurement can be performed. The error due to the backflow of the device can be reduced.

FIG. 8 is a cross section of a heating resistance type air flow meter showing another embodiment of the present invention, and FIG. 9 is an external view seen from the upstream (left side) thereof. The difference from FIGS. 1 and 2 is that two heating resistors for detecting the intake air flow rate are arranged. This is to prevent the influence of drift from the upstream.
The heating resistor is usually one (point) and the flow velocity (flow rate) in the main passage.
It measures on behalf of. However, the flow velocity distribution in the intake pipe may show various distributions. Especially, immediately downstream of the air cleaner, the shape of the air cleaner changes sensitively.
Since the heating resistance type air flow rate measuring device is often used by directly attaching the body to the air cleaner, it is necessary to take measures against uneven flow. Generally known as an unbalanced fluid measure is to measure at multiple points or to capture a wide range of flow velocity. The same applies to the product of the present invention, and if there is a drift in the detection conduit, the effect of reducing the backflow will be diminished. In the present invention as well, a wide range of flow velocities can be taken in by a throttle or the like, but it is still difficult to measure the flow rate in the main air passage with only one point. Therefore, by disposing a plurality of heating resistors in the sub air passage and measuring and averaging at a plurality of points in the detection conduit, the influence of drift and the increase of output noise are prevented.

The structure shown in FIGS. 10 and 11 is the air when a guide 18 for taking air into the detection pipe 3 is attached upstream of the throttle 8 provided at the entrance of the detection pipe 3 shown in FIG. It is a figure showing the flow of. FIG. 10 shows a case without a guide, but in the case of this structure, if the structure is such that a separation vortex is generated outside the detection conduit, the effect of adding the diaphragm 8 is reduced. This is because the pressure at the peeling portion becomes low due to the peeling on the outside, so that part of the flow velocity to be taken into the detection conduit is released to the outside. On the other hand, in FIG. 11, the thin guide 18 is provided on the upstream side of the diaphragm.
Is provided. The thickness is reduced in order to reduce the pressure applied to the tip portion of the guide 18 and to reduce the vortices of separation that occur around the guide 18 as much as possible. Therefore, the range of air intake that can be taken into the detection conduit 3 can be made wider than in the case of FIG. 10, and the effect of accelerating the flow velocity in the detection conduit due to the restriction can be enhanced.

FIG. 12 shows an embodiment in which the passage structure of the present invention is provided in a part of the air cleaner 19. In this structure, the heating resistor type air flow rate measuring device in which the driving circuit built-in module 4, the support 7, the heating resistor 5 and the temperature sensitive resistor 6 are integrated is inserted into the passage portion provided in the air cleaner. is there. As shown in the present embodiment, the passage structure of the present invention is not limited to the body of the heating resistor type air flow rate measuring device, but is disposed in a part of the components of the intake pipe of the internal combustion engine, and the heating resistor is inserted later. But the effect is the same.

FIG. 13 is a cross-sectional view of a heating resistance type air flow meter showing a further embodiment of the present invention, and FIG. 14 is an external view seen from the upstream (left side) thereof. In this structure, the circuit module 4, the plurality of heat-generating resistors 5, the temperature-sensitive resistor 6, and the detection conduit 3 having the throttle 8 at the entrance are integrally formed into a module, and an insertion hole provided in a part of the intake pipe. The detection pipe line portion 3 is inserted into and the flow rate of intake air flowing through the intake pipe is measured. At the insertion hole, a rubber material is used to seal the intake pipe and the heating resistor type air flow rate measuring device.

The method of inserting it into a part of the intake pipe is effectively no different from the effect described above. By adopting this structure, most of the functions of the heating resistor type air flow rate measuring device can be provided, and the module can be handled as one product. As a result, a company that integrates internal combustion engines, for example, a car maker, can obtain an inexpensive heating resistor type air flow rate measuring device, and further, can freely design the intake system.

FIG. 15 is a cross-sectional view of a heating resistance type air flow meter showing a further embodiment of the present invention, and FIG. 16 is an external view seen from the upstream (left side) thereof. 13 and 14, the inside of the detection conduit 3 is divided by a partition member 39. By adopting this structure, FIG. 13 and FIG.
This is because it is possible to prevent the influence of the drift from the upstream and the increase of the output noise.

Finally, FIG. 17 shows an embodiment in which the product of the present invention is applied to an electronic fuel injection type internal combustion engine.

The intake air 37 sucked from the air cleaner 24 is an intake manifold 2 having a body 1 of a heat resistance type air flow rate measuring device, an intake duct 25, a throttle body 28 and an injector 30 to which fuel is supplied.
It is sucked into the engine cylinder 32 via 9. on the other hand,
The gas 33 generated in the engine cylinder is discharged through the exhaust manifold 34.

An air flow rate signal output from the circuit module 4 of the heating resistance type air flow rate measuring device, a throttle valve angle signal output from the throttle angle sensor 27, and an oxygen concentration meter 35 provided in the exhaust manifold 34. The control unit 36, which receives the oxygen concentration signal, the engine speed signal output from the engine tachometer 31, etc., sequentially calculates these signals to obtain the optimum fuel injection amount and the idle air control valve opening. , That value is used to control the injector 30 and the idle control valve 26.

[0036]

By increasing the inertial force of the forward flow,
It is possible to reduce the reverse flow rate detected by the heating resistor by providing a change in the reverse flow velocity distribution. As a result, it is possible to provide the heating resistance type air flow rate measuring device which improves the measurement accuracy under the pulsating flow accompanied by backflow when the vehicle is mounted.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a heating resistor type air flow measuring device showing an embodiment of the present invention.

FIG. 2 is a view of FIG. 1 seen from the upstream side of the air flow.

FIG. 3 Output characteristics of boost pressure vs. heating resistor type air flow rate measuring device at constant rotation speed under pulsating flow accompanied by backflow

FIG. 4 is a pulsation waveform at points A and B in FIG.

FIG. 5 is a diagram showing a flow velocity distribution in the main passage with and without a throttle.

FIG. 6 is a cross section of a heating resistor type air flow rate measuring device showing another embodiment of the present invention.

7 is a diagram showing the flow of air in the detection pipe in the passage structure shown in FIG.

FIG. 8 is a cross-sectional view of a heating resistor type air flow rate measuring device having a plurality of heating resistors according to another embodiment of the present invention.

FIG. 9 is a view of FIG. 9 seen from the upstream side of the air flow.

FIG. 10 is a diagram showing air intake into the detection tube in the passage structure of FIG.

11 is a diagram showing air intake into the detection tube provided with a guide for air intake on the upstream side of the detection tube with respect to the passage structure of FIG.

FIG. 12 is a cross section of a heating resistor type air flow rate measuring device in which the passage structure of the present invention is integrated with an air cleaner.

FIG. 13 is a cross-sectional view of a heating resistor type air flow rate measuring device in which the passage structure of the present invention is integrated with a circuit module and inserted into a part of an intake pipe.

FIG. 14 is a diagram of FIG. 13 viewed from the upstream side of the air flow.

FIG. 15 is a cross-sectional view of a heating resistor type air flow measuring device in which a detecting tube is divided into the passage structure of FIG. 13 and heating resistors are arranged in each passage.

FIG. 16 is a view of FIG. 15 seen from the upstream side of the air flow.

FIG. 17 is a system diagram of an internal combustion engine using the heating resistor type air flow rate measuring device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Body 2 ... Main passage 3 ... Detection tube 4 ... Driving circuit built-in module 5 ... Heating resistor 6 ... Temperature sensitive resistor 7 ... Support 8 ... Detection tube throttle 9 ... Rectifier 10 ... Mainstream flow 11 ... Fixing screw 12 … Connector 1
3 ... Backflow 14 ... Support fixing part 15 ... Flat part 18 ... Guide 19 ... Air cleaner integrated passage 20 ...
Air filter 21 ... Seal material 22 ... Detection tube integrated type base 23 ... Intake pipe constituent member 24 ... Air cleaner 25 ... Duct 26 ... Idle air control valve 27 ... Throttle angle sensor 28 ... Throttle body 29 ... Intake manifold 30 ... Injector 31 ...
Tachometer 32 ... Engine cylinder 33 ... Gas 34 ... Exhaust manifold 35 ... Oxygen concentration meter 36 ... Control unit 37 ... Intake air 38 ... Bridge part 39 ... Partition material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinya Igarashi 2471, Kashima Yatsu, Hitachi Takanaka City, Ibaraki Pref. 3 Hitachi Automotive Engineers Ring Co., Ltd. (72) Inventor, Hiroshi Hirayama Kajima, Hitachinaka City, Ibaraki Prefecture Yatsu 2477 Address 3 Hitachi Automotive Engineering Co., Ltd. (72) Inventor Takayuki Saito Takata, Ibaraki Pref. Takashima Kashima Yatsu 2477 Address 3 Hitachi Automotive Engineering Ring Co., Ltd. (72) Inventor Nobukatsu Arai Tsuchiura City, Ibaraki Prefecture 502, Machi

Claims (10)

[Claims] 1. A detection tube having a heat generating resistor therein, which is substantially parallel to a main passage forming a part of an intake passage of an internal combustion engine, and an electronic circuit electrically connected to the heat generating resistor. In the heating resistor type air flow rate measuring device, the size of the detection tube is such that the effective cross-sectional area of the detection tube is approximately 20% or more of the effective cross-sectional area of the main air passage. On the upstream side, the air flow near the inner wall of the detection tube is disturbed,
A heating resistor type air flow rate measuring device characterized in that structural means for increasing the flow velocity near the center of the detection tube is provided, and the detection tube support member and the detection tube are integrally formed. 2. A detection tube having a heat-generating resistor therein, which is substantially parallel to a main passage forming a part of an intake passage of an internal combustion engine, and an electronic circuit electrically connected to the heat-generating resistor. The heating resistor type air flow rate measuring device is characterized in that it has a flow velocity distribution such that a flow velocity near the heating resistor in the detection pipe becomes faster than a flow velocity in any other portion in the detection pipe and in the main passage. Heating resistor type air flow rate measuring device. 3. The structural means according to claim 1 or 2, wherein a throttling structure is provided so that the effective cross-sectional area of the detection tube upstream of the effective cross-sectional area of the heating resistor in the detection tube is narrowed. A heating resistance type air flow rate measuring device. 4. The size of the diaphragm according to claim 3, wherein the effective area of the upstream detection tube is approximately 80% or less of the effective area of the heating resistor installed. Item 3. A heating resistance type air flow rate measuring device according to Item 3. 5. The heating resistance type air flow rate measuring device according to claim 1, wherein a plurality of heating resistors are arranged in the detection tube. 6. The inside of the detection tube is divided into a plurality of or a plurality of detection tubes are provided, and a heating resistor is arranged in each of the detection tubes, and each of the detection tubes has the diaphragm structure according to claim 4. Heating resistance type air flow rate measuring device. 7. An intake pipe component of an internal combustion engine, which comprises the detection pipe structure according to any one of claims 1 to 6. 8. A heating resistance type air flow rate measuring device characterized in that a heating resistor is inserted into the intake pipe constituent parts of the internal combustion engine according to claim 7 to detect the flow rate. 9. A heat-sensitive resistor for arranging a heat-generating resistor and a temperature-sensitive resistor in the detection tube according to claim 1, and further for detecting the heat-generating resistor and intake air temperature. Is electrically connected to the drive circuit by a conductive member and is integrally formed by a support member made of a non-conductive member, and a housing member for internally protecting the drive circuit and a connector for external interface. Is integrally fixed, the circuit part and the detection pipe part are integrated into a module, and the detection pipe part is inserted into the main air passage through a hole provided in the wall surface of the main air passage, and the main air passage is partly connected to the main air passage. A heating resistance type air flow rate measuring device characterized by being fixed to the outer wall surface of the passage. 10. A signal from a heating resistor type air flow rate measuring device provided in an intake pipe line of an internal combustion engine and an opening of a throttle valve provided downstream of the heating resistor type air flow rate measuring device in the intake pipe line. Based on the output signal from the detecting means for detecting, the output signal from the detecting means for detecting the rotational speed of the internal combustion engine, the output signal from the detecting means for detecting the oxygen concentration in the exhaust gas of the internal combustion engine, etc. In an internal combustion engine control system for controlling a fuel supply amount, an output signal from the heating resistor type air flow rate measuring device is obtained by the heating resistor type air flow rate measuring device according to any one of claims 1 to 9. A control system for an internal combustion engine, wherein the control signal is an output signal.