JP2001021400A - Heating resistor type air flow measurement device - Google Patents

Abstract

(57) [Problem] To provide a heating resistor type air flow measuring device which can be easily reduced in size and cost and can always maintain high accuracy even in various temperature environments. SOLUTION: Heat is generated by disposing a heating resistor 4 and a temperature-sensitive resistor 5 at a right angle to a flow direction B of air by respective supporting members 6a, 6b, 7a, 7b attached to a wall surface of an air passage. In the resistor type air flow measuring device, at least the support member 7b has a portion 7b for supporting the temperature-sensitive resistor 5
1 and a portion 7b2 independent of the first portion 1 is provided, and a heat radiation effect obtained by exposing the portion 7b2 to the air flow causes an effect of heat received by the temperature-sensitive resistor 5 from the wall surface of the air passage. One that can be changed independently at one end and the other. [Effect] Since the heat balance at both ends of the temperature-sensitive resistor 5 can be maintained, even when the wall temperature of the air passage changes, the possibility that the temperature correction changes can be suppressed, and high measurement accuracy can be maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air flow measuring device using a heating resistor, and more particularly to a heating resistor type air flow measuring device suitable for measuring an intake air flow of an automobile engine.

[0002]

2. Description of the Related Art A heating resistance type air flow rate measuring apparatus has been widely used as an intake air flow rate measuring apparatus for an internal combustion engine because it has no moving parts and can directly measure a mass flow whose temperature has been corrected. At this time, it is necessary to prevent the heating resistor and the temperature-sensitive resistor serving as the measuring elements from being affected by the temperature other than the intake air (intake air) to be measured, which is an important requirement for measurement accuracy. Become.

For example, in Japanese Patent Application Laid-Open No. 60-36916, a heat-generating resistor and a temperature-sensitive resistor are used to balance the effects of heat conduction and heat dissipation generated through their supporting members. A heating resistor type air flow measuring device in which a molded member of a housing holding a body supporting member is counterbore is proposed.

[0004] This is because even when the temperature outside the intake pipe and the temperature of the intake air are different from each other, the thermal effect on both resistors generated through the support member is balanced.
The purpose of the present invention is to reduce the measurement error of the heating resistor type air flow measuring device under the above-mentioned temperature environment.

For example, Japanese Patent Application Laid-Open No. 10-281836 proposes a heating resistor type air flow measuring device in which a heating resistor and a temperature sensitive resistor are arranged so as to be parallel to respective support members. This is because, by arranging the support member and the resistor parallel to the main direction of the intake air, the width of the auxiliary air passage in which the support member and the resistor are arranged can be reduced, and the pressure loss can be reduced. Is obtained.

[0006]

However, the above prior art does not give sufficient consideration to the heat balance between the heating resistor and the temperature-sensitive resistor, and has problems in maintaining measurement accuracy and miniaturizing the apparatus. was there. That is, first, JP-A-60-3691
In the device according to Japanese Patent Publication No. 6, the length of the supporting members of the heating resistor and the temperature-sensitive resistor is made the same so that each resistor has the same effect of the heat received by each supporting member. However, at this time, in order to reduce the influence of the wall temperature of the housing, the positions of the heat generating resistor and the temperature sensitive resistor are adjusted, or a counterbore is formed in a mold member holding a support member of the temperature sensitive resistor. Was.

However, for this reason, the supporting members of the respective resistors are supported so as to be perpendicular to the respective resistors, and the length of the portion where these supporting members are exposed to the intake air is sufficiently long. It is necessary to secure them, and as a result, the auxiliary air passage containing them needs to be large enough.
This causes a problem in reducing the pressure loss and promoting the simplification and downsizing of the support member structure.

On the other hand, when each resistor is made parallel to each support member as in the device disclosed in Japanese Patent Application Laid-Open No. 10-281836, the length of the portion where the resistance support member is exposed to the intake air is reduced. In addition, it is difficult to ensure sufficient resistance, and the length of the supporting members at both ends of the resistor is different, so that the effects of heat on each resistor are not equal at both ends, and the heat balance at both ends is not balanced. A measurement error due to collapse and a measurement error due to heat conduction between the housing and the resistor via the short support member become problems.

As a countermeasure against this, Japanese Patent Laid-Open No. 60-3
As described in Japanese Patent Application Laid-Open No. 6916, if a counterbore is formed in a mold member that holds the supporting members of both resistors, a problem such as a sudden change in the cross-sectional area of the passage of the heating resistor installation portion may cause a change in flow. Occurs, and is an obstacle to miniaturization.

Further, when each resistor and each support member are made parallel, the influence of the support member on the air flow becomes a problem. For example, if a support member or a temperature-sensitive resistor is located upstream of the heat-generating resistor, the heat-generating resistor may enter a turbulent flow region generated by the support member or the temperature-sensitive resistor, which deteriorates measurement accuracy and increases output noise. Problem arises.

An object of the present invention is to provide a heating resistor type air flow measuring device which can be easily reduced in size and cost and can always maintain high accuracy even in various temperature environments.

[0012]

The above object is achieved by using two support members attached to the wall of a passage through which air whose flow rate is to be measured is installed at right angles to the direction of air flow. A heating resistor type air flow measuring device comprising a substantially cylindrical heating resistor and a temperature-sensitive resistor, detecting a flow rate by the heating resistor, and compensating for the temperature by the temperature-sensitive resistor; The support member of the temperature-sensitive resistor is provided with a protruding portion independent of the support portion of the resistor,
This is achieved by providing a temperature balance at both ends of the resistor by the heat radiation effect of the projecting portion.

According to the embodiment, in the present invention,
The supporting members for the heating resistor and the temperature-sensitive resistor are as follows. (1) Even if the lengths of the support members at both ends of the resistor are different, it is possible to reduce the difference in thermal effects between the two and to branch off into short support members in the middle so as to reduce the heat conduction of the short support members. A radiator plate exposed to the air was provided.

[0014] Accordingly, the thermal effect via the support member can be reduced without increasing the distance from the fixing portion of the support member to the housing to the resistor fixing portion. By increasing the cross-sectional area or surface area on the heat sink side compared to the fixed side, the heat dissipation effect can be improved.

(2) In order to enhance the heat transfer of the heat radiating plate or the long supporting member to the air, the heat radiating plate or the long supporting member is placed downstream of the temperature-sensitive resistor in a turbulent flow region where the intake air is disturbed by the temperature-sensitive resistor. It was configured. Conversely, a temperature-sensitive resistor is arranged downstream of the support member, and turbulence generated by the support member causes
The heat transfer of the temperature sensitive resistor was improved, and the air temperature detection was made more accurate.

(3) The support member is provided with a plate-like portion parallel to the direction of air flow in the vicinity thereof, so that the flow in the vicinity of the resistor is rectified. In addition, by bending the plate-like portion of the support member into a substantially rectangular shape or a substantially arc shape, the direction of air flow is optimized, and the flow near the resistor is rectified by reducing the flow rate.

(4) A guide plate for smoothly bending the flow of air is provided, for example, by arranging the plate-like portion of the support member in the bent direction in the bent air passage.

As a result, the following has become possible. (1) Simplified structure, miniaturization, and cost reduction.

(2) Higher accuracy and improved temperature characteristics.

(3) Reduction of output noise.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a heating resistor type air flow measuring device according to the present invention will be described in detail with reference to the illustrated embodiments. First, FIGS. 1 to 4 show a first embodiment of the present invention. FIG. 1 is a cross-sectional view, FIG. 2 is a front view, and FIG. 1 is a cross-sectional view taken along line AA of FIG. FIG. 2 is a view as seen from the direction of arrow B in FIG. 1, and arrow B in FIG. 1 also represents the direction of intake air flow. Then, FIG.
FIG. 4 is an enlarged view of the portion viewed from the intake air flow direction B. FIG.
FIG. 2 is an enlarged view of a portion C in FIG. 1 as it is.

As shown in these figures, in this embodiment, first, the main air passage 1 is formed by the air flow meter body 3, and the sub air passage 2 is provided in the main air passage 1. A heating resistor 4 and a temperature-sensitive resistor 5 serving as elements for detecting the flow rate of intake air are provided inside the auxiliary air passage 2.

Here, the heating resistor 4 is moved in the intake air flow direction B
Along the front support member 6a at the front and the rear support member 6b at the rear, and the temperature-sensitive resistor 5 is also at the front support member 7a at the front and the rear support member 7b at the rear,
Each is supported in the auxiliary air passage 2 so as to be perpendicular to the intake air flow direction B.

These support members 6a, 6b, 7a, 7b
Is made of a conductive material such as stainless steel, and is connected to a predetermined circuit of the electronic circuit 8, thereby
The heating resistor 4 and the temperature-sensitive resistor 5 are electrically connected to the electronic circuit 8 via these support members 6a, 6b, 7a, 7b, respectively.

The electronic circuit 8 is housed in a housing 9 which is formed integrally with the auxiliary air passage 2 and, as shown in FIG. Inserted and mounted.

As is clear from FIGS. 1 and 4, the heating resistor 4 and the temperature-sensitive resistor 5 are arranged in front of the temperature-sensitive resistor 5 in the intake air flow direction B inside the auxiliary air passage 2. 3, and furthermore, as is clear from FIG.
Inside the sub air passage 2, they are arranged so as to be mutually shifted in a direction perpendicular to the intake air flow direction B.

Each of the support members 6a and 6b and the support members 7a and 7b are parallel to the heating resistor 4 and the temperature-sensitive resistor 5, as shown in detail in FIGS. , So that the front support members 6a, 7a
The rear support members 6b and 7b have different lengths up to the attachment portion to the auxiliary air passage 2, and the front support portion 6a and the rear support member 7b are shorter.

The rear support member 6b of the heating resistor 4 is formed with a bent portion 6b1 in the middle, as clearly shown in FIG. At right angles to the flow direction B, a position shifted toward the temperature-sensitive resistor 5 is taken.

Further, the support member 7b of the temperature-sensitive resistor 5 includes
A protruding portion 7b2 extending as it is and having a cantilever shape is formed, and a portion 7b1 protruding at a right angle is formed in the middle of the protruding portion 7b2, on which one of the thermal resistors 5 is supported. That is, the portion 7b1 serves as a support for the thermal resistor 5, and the protruding portion 7b2 is formed independently of this support.

The protruding portion 7b2 is for heat dissipation, and therefore, as clearly shown in FIG. 3, is bent at the portion where the portion 7b1 protrudes, on the side opposite to the heating resistor 4, to allow the intake air flow. At right angles to the direction B, a position deviated from the temperature-sensitive resistor 5 is taken, so as to be well exposed to the air flowing through the sub air passage 2.

Next, the operation of this embodiment will be described with reference to FIG.
This will be described below. FIG. 5 is an enlarged view of FIG. 4, where 2a denotes a wall surface of the auxiliary air passage 2 where a support member is held. The temperature of the wall surface 2a is referred to as a wall temperature Tw, and the temperature of the intake air is referred to as an intake air temperature Ta. Here, since the wall temperature Tw is strongly affected by the temperature of the engine to which the air flow measuring device is applied, the wall temperature Tw is usually higher than the intake air temperature Ta, and generally (Tw ≧
Ta).

Next, the heat balance at both ends of the heating resistor 4 and the heat balance at both ends of the temperature-sensitive resistor 5 will be described. First, the heating resistor 4 will be described. Since the heating resistor 4 is controlled to maintain a temperature higher than the intake air temperature Ta by a predetermined temperature, the heat balance during operation is as follows.
Heat amounts q1a, q1b that are thermally conducted to the wall surface 2a through the front support member 6a and the rear support member 6b, and heat amounts q2a, q2 that are dissipated into the intake air from the front support member 6a and the rear support member 6b.
b.

Next, the temperature-sensitive resistor 5 is used in such a manner that it generates only negligible heat in practical use, so that its temperature is controlled by the intake air temperature Ta. Therefore, as described above, the heat balance greatly affects the measurement accuracy of the air flow rate, and maintaining the same heat balance at all times is a great requirement for maintaining high measurement accuracy.

Therefore, the heat balance in the temperature-sensitive resistor 5 in this embodiment will be described below. First, FIG.
When Tw = Ta shown in (a), that is, when the wall temperature Tw is equal to the intake air temperature Ta, the temperature of the temperature-sensitive resistor 5 is also changed to the wall temperature Tw.
Is equal to Therefore, at this time, since there is no temperature difference between the wall surface 2a and the temperature-sensitive resistor 5, there is no heat flow through the support members 7a and 7b, and therefore, the temperature at both ends of the temperature-sensitive resistor 5 is It will be the same and the heat balance will be maintained.

Next, when Ta <Tw shown in FIG.
That is, the case where the wall temperature Tw becomes higher than the intake air temperature Ta will be described. In this case, as shown, the flow of the heat quantity q4a via the front support member 7a and the flow of the heat quantity q4b via the rear support member 7b are shown. Flows respectively occur.

Here, if it is assumed that the portion 7b2 is not provided, the front support member 7a holding one end (the lower end in the figure) of the temperature-sensitive resistor 5 and the temperature-sensitive resistor 5
The rear support member 7 holding the other end (the upper end) of the
Calories q4a and q4b
And the temperature at both ends of the temperature-sensitive resistor 5 is different. Specifically, the calorific value q4b increases, and the temperature at the upper end of the temperature-sensitive resistor 5 increases. You lose your balance.

In this embodiment, however, the rear support member 7b is provided with the portion 7b2, which is exposed to the intake air flow, and thus functions as a radiator plate, so that the amount of heat q4b2 flowing through this portion 7b2 is generated. The amount of heat flowing to the upper end of the thermal resistor 5 is the amount of heat q4b1 obtained by subtracting the amount of heat q4b2 from the amount of heat q4b.

Therefore, in this embodiment, the size and shape of the portion 7b2 provided on the support member 7b are set to a predetermined state, so that even when the wall temperature Tw becomes higher than the intake air temperature Ta, the wall 7B2 can be used. As in the case where the temperature Tw is equal to the intake air temperature Ta, it is possible to always maintain a state where the heat balance at both ends is maintained. As a result, according to this embodiment, even when the environmental condition changes, the total amount of heat received by the heating resistor and the temperature-sensitive resistor through each of the supports can be made substantially equal, and the measurement accuracy is always improved. Can be kept high.

That is, the amount of heat dissipated by the heating resistor through the support when Ta = Tw, the amount of heat dissipated by the heating resistor through the support when Ta <Tw, and the amount of heat received by the temperature-sensitive resistor through the support are substantially equal. In order to make them the same, in the embodiment, it is possible to easily achieve this by keeping the heat balance at both ends of the temperature-sensitive resistor.

In the above embodiment, the portion 7b2 functioning as a heat radiating plate will be described in more detail. The portion 7b2 is located behind the temperature-sensitive resistor 5 and is a branch point at a position where the temperature-sensitive resistor 5 is held. It is bent in the vicinity and is arranged in a turbulent flow region where the intake air flow is disturbed by the temperature-sensitive resistor 5 at a position shifted from the temperature-sensitive resistor 5 with respect to the flow direction B of the intake air flow.

As described above, the portion 7b2 serving as a heat radiating plate
In the turbulent flow region, the heat transfer to the intake air flow can be increased, and as a result, the collapse of the heat balance due to the short length of the rear support member 7b can be further reduced.

Further, in this embodiment, the portion 7b2 serving as a heat sink is connected to the supporting members 7a and 7b of the temperature-sensitive resistor 5 and the heating resistor 4 with respect to the temperature-sensitive resistor 5 itself and the center of the auxiliary air passage 2. The structure on the opposite side that does not overlap in the flow direction of the intake air is to increase the area where the portion 7b2 is exposed to the intake air.

Therefore, the rear support member 7 of the temperature-sensitive resistor 4
b can further reduce the influence of heat transfer and heat conduction on the temperature-sensitive resistor 5.

In this embodiment, the portion 7b2 has a structure parallel to the supporting member 7b with respect to the flow direction of the intake air. This is because the width of the auxiliary air passage 2 can be reduced while sufficiently maintaining the heat radiation effect. Because it can be made smaller,
Therefore, the pressure loss can be reduced.

Similarly, after the distance from the housing to the heat-generating resistor in the support member for the heat-generating resistor 4 is long, the support member 6b has a bent portion 6b1 in the middle, and the heat-generating resistor 4 and the temperature-sensitive resistor 5 The position that does not overlap with the flow direction of the intake air prevents the heat generated by the heat generating resistor 4 from being affected by the heat radiated.

Finally, the support member structure according to this embodiment can improve the integral molding property of the support member, and furthermore, it is difficult to form the mold by the conventional support member having a complicated shape. Automation can be achieved, and the unit price of product parts can be reduced.

Next, another embodiment of the present invention will be described. First, FIGS. 6 and 7 show another embodiment of the present invention. Here, FIG. 6 is an external view of intake air as viewed from upstream, and FIG. 7 is a side view of FIG. In these figures, 10 is a shorter supporting member, 11 is a resistor, and 12 is a longer supporting member.

Here, the support member 1 in this embodiment is
0 corresponds to, for example, the support member 6a or the support member 7b in the embodiment described with reference to FIGS. 1 to 5, the resistor 11 also corresponds to the heating resistor 4 or the temperature-sensitive resistor 5, and further, the support member 12 Also corresponds to the support member 6b or the support member 7a.

The embodiment shown in FIGS. 6 and 7
The resistor 11 has a rectangular shape, and the resistor 11 is
2 and is formed on the same plane as the portion 10b serving as a heat sink. Therefore, according to this embodiment, an effect similar to that of the embodiment shown in FIGS. 1 to 4 can be obtained.

FIGS. 8 and 9 show another embodiment of the present invention.
FIG. 8 is an external view of the intake air as viewed from upstream, and FIG. 9 is a side view of FIG. The embodiment shown in FIGS.
The resistor 11 is formed in a plate shape, and the resistor 11 is parallel to a portion 10a serving as a support portion for supporting one end of the resistor 11 in the resistor support member 10, and a portion 10b serving as a heat sink and the support member 12. And are made on the same plane.

Therefore, according to this embodiment, the same effects as those of the embodiment shown in FIGS. 1 to 4 can be obtained, and the width of the auxiliary air passage 2 can be further reduced by reducing the sensor width. And the pressure loss can be further reduced.

FIGS. 10 and 12 show an embodiment of the present invention. FIG. 10 is an external view of the intake air as viewed from upstream.
FIG. 11 is a side view of FIG.

In the embodiments shown in FIGS. 10 and 11, the portion 10a of the resistor support member 10 serving as a support portion for supporting one end of the resistor 11 functions as a heat sink rather than its width. This is an embodiment in which the width of the portion 10b is made wider. Therefore, by adopting this embodiment as the rear support member shown in FIGS. 1 to 4, the embodiment shown in FIGS. The same operation and effect as described above can be obtained.

According to the embodiment shown in FIGS. 10 and 11, the area where the portion 10b serving as the heat radiating plate is exposed to the intake air can be made sufficiently large. The effect of heat transfer and heat conduction on the resistor can be further reduced.

FIGS. 12 and 13 show another embodiment of the present invention. FIG. 12 is a front view in which the left side is positioned upstream of the intake flow, and FIG. It is the side view seen from the arrow X direction of twelve. In this embodiment,
First, the support members 10 and 12 are formed to have a cross section that is long in a direction parallel to the direction of the flow of the intake air.

The support members 10 and 12 are
It is attached to the housing 9 in a state where the whole is bent so as to form the same arc along the direction of the flow of the intake air, and the resistor 11 is parallel to the support members 10 and 12, and At a portion extending on the same arc in the flow direction, it is mounted at right angles to the flow direction.

Therefore, according to this embodiment, the same effects as those of the embodiment shown in FIGS. 1 to 4 can be obtained, and the flow of the intake air can be reduced because the support member has a circular arc shape as a whole. Resistor 1 without being disturbed by support member 12
1 and then flows along the support member 10 which is also bent in the same arc, so that the area where the air flow appears to be separated can be moved to the rear of the resistor 11 as shown.

Therefore, according to this embodiment, the resistor 1
Since the turbulence of the air flow when passing through 1 is suppressed, the noise of the detection signal can be sufficiently reduced, and as a result, the effect of easily maintaining high measurement accuracy can be obtained.

Next, FIGS. 14 and 15 show still another embodiment of the present invention. Here, FIG. 14 is a front view in which the left side of FIG. 15 is FIG.
FIG. 4 is a sectional view taken along line YY of FIG.

In this embodiment, a short supporting member 10 having a portion 10b serving as a heat radiating plate is provided on the upstream side of the resistor 11, and the portion 10b serving as a heat radiating plate is further provided in the flow direction of the intake air. The angle θ of the inclination is an angle effective to increase the flow velocity of the air toward the resistor 11.

Therefore, according to this embodiment, similarly to the embodiment shown in FIGS. 1 to 4, even when the wall temperature becomes high, the same heat balance as in the normal temperature state can be easily achieved. A high measurement accuracy can be easily maintained, and a portion 10b serving as a heat sink further includes a resistor 11b.
It also has the effect of increasing the flow velocity of the air flowing into the chamber and stabilizing the flow, so that a decrease in detection sensitivity at low flow rates is suppressed and output noise is also reduced.

Next, FIGS. 16 and 17 show another embodiment of the present invention. FIG. 16 is a front view in which the left side is in the upstream direction of the intake air, and FIG. It is sectional drawing by a line.

This embodiment is different from the first embodiment in that a shorter supporting member 10 is provided on the upstream side of the resistor 11 and the supporting member 10 is arranged in parallel with the resistor 11 together with the longer supporting member 12. , 10 and 11, but here the shorter support member 10
A portion 10b1 extending upstream of the intake air;
And a portion 10b2 which reaches the vicinity of the longer support member 12 through the lower side of the support member 12.

Here, the portion 10b1 extending to the upstream side is
As shown, it is bent downward at an angle θ, and as a result, together with the rearwardly extending portion 10b2,
While increasing the flow velocity of the air flowing from the upstream side, the resistor 1
It works to guide you in one direction.

Therefore, according to this embodiment, FIGS.
The same effects as those of the embodiment shown in FIG. 4 can be obtained.
By providing these portions 10b1 and 10b2, the same effect as when the sub-air passage 2 is formed in the contracted flow structure can be obtained. The benefits of doing so can be obtained.

Next, FIG. 18 is a cross-sectional view showing the inside of the sub air passage 2 with the left side of the drawing being on the upstream side of the air flow. This is an embodiment of the present invention in which a bent portion 2a having a substantially right angle is provided, and a resistor 11 is arranged near the upstream side.

In this embodiment, the longer support member 12 is placed upstream of the resistor 11 and the shorter support member 10
Is disposed downstream, and the shorter support member 10 is provided with a portion 10b serving as a heat sink.
This embodiment is the same as the embodiment described with reference to FIGS. 1 to 4, but here, this portion 10 b is further extended to the downstream side of the auxiliary air passage 2 so as to enter the bent portion 2 a.

As shown in the figure, the portion 10b is bent along the bent portion 2a on the way, and the bending angle θ at this time is such that the intake air flowing through the sub air passage 2 is
The angle is selected so that it can easily flow in the bent portion 2a.

Therefore, according to this embodiment, even if the auxiliary air passage 2 has the bent portion 2a, the flow of air in the bent portion 2a is smoothed by the action of the portion 10b, so that the bent portion 2a is smoothed. 2a is reduced, and as a result, the same effects as in the embodiment shown in FIGS. 1 to 4 can be obtained, and the flow velocity of the air flowing in the sub air passage 2 can be increased. .

The heating resistance type air flow rate measuring apparatus according to the present invention is suitable for measuring the intake air flow rate of an automobile engine. In this case, the apparatus is installed and used in an intake path of an engine provided with a throttle valve. Will be. FIG. 15 shows an embodiment in which the present invention is applied to an automobile engine.

In FIG. 19, reference numeral 14 denotes a throttle body, reference numeral 15 denotes a throttle valve (throttle valve), and the other components are the same as those of the embodiment shown in FIGS. As in the embodiment of FIG. 1, the housing 9 of the air flow measuring device in which the auxiliary air passage 2 is integrated is inserted and attached to the throttle body 14, and a throttle valve 15 is disposed downstream of the housing 9. ing.

Here, the support of the heating resistor 4 and the thermal resistor 5 arranged in the sub air passage 2 will be described with reference to FIGS.
Any of the embodiments described above can be applied. Therefore, according to this embodiment, the same effects as those of the embodiment described with reference to FIGS. 1 to 18 can be obtained, and the structure can be simplified by integration with the throttle body and the handling can be simplified. Can be.

Next, FIG. 20 shows an embodiment in which the present invention is further integrated with an air cleaner disposed in an engine room. In the drawing, reference numeral 16 denotes an air cleaner, which is connected to an upstream case member 16a and a downstream case member 16a. Side case member 16b
Are assembled by sandwiching and fixing the filter member 16c.

The upstream case member 16a is provided with an introduction duct 17 for taking in intake air, and the intake air introduced therefrom passes through a filter member 16c to remove dust contained therein. Then, it is introduced into the downstream side case member 16b.

Then, the air is introduced into an intake pipe of the engine by an intake duct 18 provided in the downstream case member 16b. Therefore, in this embodiment, by attaching the housing 9 of the air flow measuring device described with reference to FIGS.
The air flow measuring device is integrated with the device.

Therefore, according to this embodiment, the same effects as those of the embodiment described with reference to FIGS. 1 to 18 can be obtained, and the structure can be simplified and the handling can be simplified by integration with the air cleaner. be able to.

Next, FIG. 21 shows an embodiment in which the present invention is applied to an internal combustion engine of the electronic fuel injection type. In this figure, the air flow meter body 3 is the same as that shown in FIGS. It is an air flow measuring device according to a form. The intake air taken in from the air cleaner 19 passes through an air flow meter body 3, an intake duct 20, a throttle body 15, and a manifold 22 having an injector 21 for fuel injection, and is sucked into a cylinder 23 of the engine.

On the other hand, gas generated in the cylinder 23 of the engine is discharged through the exhaust manifold 24.

At this time, an air flow signal is output from the electronic circuit of the heating resistor type air flow measurement device, a throttle valve angle signal is output from the throttle angle sensor 25, and an oxygen concentration meter 26 provided in the exhaust manifold 24 is output. An oxygen concentration signal is output, and the rotation angle meter 2
7 outputs a rotation speed signal.

Therefore, these signals are input to the control unit 28, and the results calculated here are output to the injector 21 and the idle air control valve 29, so that the fuel injection amount and the idle air amount of the engine are optimized. It will be controlled to be in a state.

Therefore, according to this embodiment, since the air flow rate signal can be obtained with high accuracy, the engine can always be controlled to an optimum state, and the improvement of the fuel efficiency of the automobile and the sufficient purification of the exhaust gas can be easily obtained. be able to.

[0082]

According to the present invention, the effect of the wall temperature, which is a problem when the width of the sub air passage is reduced, can be sufficiently reduced, the noise included in the air flow signal can be reduced, and the air in the sub air passage can be reduced. Since the flow velocity can be increased, it is possible to sufficiently improve the measurement accuracy of the heat-generating air flow measuring device, and to easily provide a user-friendly heat-generating air flow measuring device.

[Brief description of the drawings]

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

FIG. 2 is a front view showing a first embodiment of a heating resistance type air flow measuring device according to the present invention.

FIG. 3 is an enlarged view of a main part of the first embodiment of the heating resistance type air flow measuring device according to the present invention.

FIG. 4 is an enlarged view of a main part of the first embodiment of the heating resistance type air flow measuring device according to the present invention.

FIG. 5 is an enlarged view of a main part for explaining the operation of the first embodiment of the present invention.

FIG. 6 is an enlarged front view of a main part according to a second embodiment of the present invention.

FIG. 7 is an enlarged side view of a main part according to a second embodiment of the present invention.

FIG. 8 is an enlarged front view of a main part according to a third embodiment of the present invention.

FIG. 9 is an enlarged side view of a main part according to a third embodiment of the present invention.

FIG. 10 is an enlarged front view of a main part according to a fourth embodiment of the present invention.

FIG. 11 is an enlarged side view of a main part according to a fourth embodiment of the present invention.

FIG. 12 is an enlarged side view of a main part according to a fifth embodiment of the present invention.

FIG. 13 is an enlarged top view of a main part according to a fifth embodiment of the present invention.

FIG. 14 is an enlarged side view of a main part according to a sixth embodiment of the present invention.

FIG. 15 is an enlarged top view of a main part according to a sixth embodiment of the present invention.

FIG. 16 is an enlarged side view of a main part according to a seventh embodiment of the present invention.

FIG. 17 is an enlarged top view of a main part according to a seventh embodiment of the present invention.

FIG. 18 is a sectional view showing an eighth embodiment of the present invention.

FIG. 19 is a sectional view showing a ninth embodiment of the present invention.

FIG. 20 is a sectional view showing a tenth embodiment of the present invention.

FIG. 21 is a system configuration diagram showing an eleventh embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main air passage 2 Sub air passage 3 Air flow meter body 4 Heating resistor 5 Temperature sensitive resistor 6a Front support member 6b Rear support member 7a Front support member 7b Rear support members 7b1, 7b2 Part branched from support member 8 Electron Circuit 9 Housing 10 Short resistor support member 10a, 10b Portion branched from support member 11 Resistor 12 Long resistor support member 13 Bending angle of heat sink 14 Throttle body 15 Throttle valve 16 Air cleaner 16a Upstream case 16b Downstream case 16c Filter member 17 Introductory duct 18 Intake duct 19 Air cleaner 20 Intake duct 21 Injector 22 Manifold 23 Engine cylinder 24 Exhaust manifold 25 Throttle angle sensor 26 Oxygen concentration meter 27 Rotation angle meter 28 Control unit 29 A Idle air control valve

 ────────────────────────────────────────────────── ─── Continued from the front page (72) Inventor Shinya Igarashi 2477 Takaba, Hitachinaka-shi, Ibaraki F-term in Hitachi Car Engineering Co., Ltd. (Reference) 2F035 AA02 EA03 EA04 3G084 DA04 DA13 FA08

Claims (21)

[Claims] 1. By using two support members each mounted on the wall of a passage through which the air whose flow rate is to be measured flows,
It comprises a heating resistor and a temperature-sensitive resistor installed at right angles to the flow direction of the air, and detects a flow rate by the heating resistor,
In the heating resistor type air flow rate measuring device wherein the temperature is compensated by the temperature-sensitive resistor, at least a supporting member of the temperature-sensitive resistor is provided with a projecting portion independent of a supporting portion of the resistor, and the projecting portion is provided. A heat-generating resistor-type air flow measuring device, characterized in that a temperature balance at both ends of the resistor is given by a heat radiating action of the heating element. 2. The invention according to claim 1, wherein the pair of support members to which at least one of both ends of the heating resistor and the temperature-sensitive resistor are fixed extend in a direction substantially parallel to the longitudinal direction of the resistor. One is bent in the vicinity of the tip, the other has a branch-like portion branched in the middle, and the resistor support has both ends of the resistor supported by the one portion and the other portion. A heating resistor type air flow measuring device having a structure. 3. The invention according to claim 2, wherein a portion of the support member extending substantially in parallel with the resistor is formed in a shape having a larger cross-sectional area than the bent portion. Features a heating resistor type air flow measurement device. 4. The invention according to claim 2, wherein the portion of the support member extending substantially in parallel with the resistor has a plate-like shape, and has a width wider than that of the bent portion. A heating resistor type air flow measuring device, characterized in that: 5. The invention according to claim 2, wherein the portion of the support member substantially parallel to the resistor extends in a direction substantially perpendicular to the main flow direction of the air flowing in the vicinity thereof. Heating resistor type air flow measurement device. 6. The invention according to claim 4, wherein the plate-shaped portion of the support member extending substantially in parallel with the resistor is provided.
A heating resistor type air flow measuring device, wherein a plate-like surface is formed substantially parallel to a main flow direction of air flowing in the vicinity thereof. 7. The method according to claim 2, wherein one of the pair of support members formed substantially parallel to the temperature-sensitive resistor is arranged in a main flow direction of air flowing in the vicinity thereof. Heat generation is characterized by being arranged upstream of the temperature-sensitive resistor, the temperature-sensitive resistor being formed in a position where the periphery thereof becomes a turbulent flow region generated by the support member arranged at the upstream. Resistor type air flow measurement device. 8. The invention according to claim 2, wherein one of the pair of support members formed substantially parallel to the temperature-sensitive resistor is arranged in a main flow direction of the air flowing in the vicinity thereof. A heating resistor-type air flow measuring device, which is disposed downstream of the temperature-sensitive resistor, and the periphery of the supporting member is formed at a position serving as a turbulent flow region generated by the temperature-sensitive resistor. . 9. The invention according to claim 6, wherein at least one of the heating resistor and the temperature-sensitive resistor is a resistor formed on a plate-shaped substrate, and the plate-shaped resistor is the support member. A heating resistor-type air flow measuring device, which is arranged substantially on the same plane as a plate-like portion extending substantially parallel to the resistor. 10. The invention according to claim 9, wherein the plate-shaped resistor and the plate-shaped portion of the support member are arranged substantially on the same plane in a direction substantially parallel to a flow direction of air flowing in the vicinity thereof. A heating resistor type air flow measuring device, characterized in that: 11. The invention according to claim 4, wherein one of the plate-like portions of the support member extending substantially parallel to the resistor is located upstream of the resistor with respect to a flow direction of air flowing near the resistor. A heating resistor type air flow measuring device, wherein the plate-shaped surface is inclined with respect to the flow direction in the vicinity of the center of the resistor as an axis. 12. The invention according to claim 4, wherein the plate-like portion of the support member extending substantially parallel to the resistor has an upstream end portion inclined with respect to a flow direction of air flowing in the vicinity thereof. A heating resistor type air flow measuring device, which is formed by bending in a substantially rectangular shape, wherein the resistor is arranged outside the bend. 13. The invention according to claim 4, wherein a plate-like portion of the support member extending substantially parallel to the resistor is formed by being bent in a substantially arc shape, and the arc-shaped support member and its vicinity. A heating resistor-type air flow measuring device, wherein the resistor is disposed upstream of an intersection with a tangent along a flow direction of air flowing through the heating element. 14. The invention according to claim 2, wherein the portion of the support member extending substantially parallel to the resistor has a plate-like shape, and the plate-like portion is substantially in the flow direction of the air flowing in the vicinity thereof. A heating resistor-type air flow measuring device, which is formed in parallel and in parallel, wherein the resistor is disposed in a space sandwiched by the support members formed in parallel. 15. The invention according to claim 14, wherein the resistor is disposed so as to be substantially entirely surrounded by the support member portion formed in parallel and a bent portion or a branched portion of the support member. A heating resistor type air flow measuring device characterized by the following. 16. The auxiliary air passage according to any one of claims 2 to 15, wherein the resistor and the support member have a substantially rectangular or elliptical cross section whose longitudinal direction is a long side. A heating resistor type air flow measuring device, which is disposed in the inside. 17. The support member according to claim 12, wherein the support member is disposed in a sub air passage, and the support member is arranged in a flow direction of air flowing through the sub air passage. By arranging the portion to be the upstream end of the plate-shaped portion so as to substantially contact the inner wall of the auxiliary air passage,
A heat-generating resistor type air flow measuring device, characterized in that a flow contraction structure for increasing a flow velocity of air in the resistor disposing portion is provided. 18. The invention according to claim 16, wherein the auxiliary air passage has a bend at at least one position, and the support member is inclined or bent along the bending direction in the vicinity of the bent portion. The heating resistor-type air flow measuring device is characterized in that it is arranged to function as a guide plate for smoothly flowing the flow at the bent portion of the sub air passage. 19. An electronic circuit according to claim 1, wherein said electronic circuit is electrically connected to said temperature-sensitive resistor and said heating resistor, and outputs a signal corresponding to a flow rate of intake air. A housing for internally protecting the electronic circuit; and a connector disposed on one side of the frame of the housing for electrically connecting to an external device. The support member and the heating resistor are provided on the opposite side of the connector. And the temperature-sensitive resistor, so that the support member, the heat-generating resistor, and the temperature-sensitive resistor are located inside an intake pipe through which the air to be measured flows, and the connector is located outside. The heat-generating resistor-type air conditioner is characterized in that a wall surface of the housing, which is perpendicular to a flat surface of an electronic circuit in the housing, is fixed to be substantially perpendicular to a flow direction of the intake pipe. Air flow measurement device. 20. The heat generation apparatus according to claim 1, wherein the air flow meter body is integrally formed with an intake system component of the engine such as an air cleaner, a duct, and a throttle body. Resistor type air flow measurement device. 21. A control system for an internal combustion engine, wherein the heating resistor type air flow measuring device according to claim 1 is used.