JPH102775A - Heating element-type air flow rate measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a highly accurate measurement by providing a partitioning wall or plate for preventing thermal interference between a heating element and a temperature-sensitive resistor. SOLUTION: A suction air is fed through a main passage 3 and a sub-passage 4 in the body 2 to an engine. A heating resistor 5 for measuring the air flow rate and a temperature-sensitive resistor 6 for measuring the temperature of suction air are arranged in the passage 4. The resistor 5 and the resistor 6 are arranged so as not to be overlapped in the direction of suction air flow and covered with a protective member 7, constituting a part of the passage 4. The resistor 5 and the resistor 6 are connected with supporting pins 8 and further connected with an electronic circuit 10 through lead wires 9. The circuit 10 outputs a signal, related to the air flow rate based on the output signals from the resistor 5 and the resistor 6. The protective member 7 is secured to a circuit module 11 for mounting the circuit 10. A partition plate (wall) 12 prevents thermal interference between the resistor 6 and the resistor 5 and enhances the measurement accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heating resistance type air flow measuring device.

[0002]

2. Description of the Related Art In a heating resistance type air flow measuring device, it is necessary to detect the air temperature with high accuracy using a temperature sensitive resistor.
As a well-known example of the present invention, there is an air flow measuring device described in Japanese Patent Application No. 6-116240. However, as described in the present invention, a wall between the heat-generating resistor and the temperature-sensitive resistor is formed. Therefore, there is a problem that the temperature-sensitive resistor for measuring air temperature is affected by the heat generated by the heating resistor for measuring air flow.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to reduce a measurement error of a heating resistance type air flow measuring device sucked into an engine of an automobile or the like.

When a heating resistor for measuring the air flow rate is installed on the upstream side of the intake air and a temperature sensing resistor for measuring the intake air temperature is installed on the downstream side, the heating resistor is connected to the upstream heating resistor. Since an air temperature affected by heat radiation from the body is detected, a measurement error occurs, and it is necessary to prevent this thermal interference.

[0005]

Means for Solving the Problems In the sub-passage where the heating resistor and the temperature-sensitive resistor are installed, a wall or a partition plate is provided to prevent heat interference between the heating resistor and the temperature-sensitive resistor.

[0006]

FIG. 1 is a cross-sectional view of a heating resistance type air flow measuring device according to an embodiment of the present invention, and FIG. 2 is a front view as viewed from the left side of FIG. The intake air 1 is supplied to the engine through a main passage 3 and a sub passage 4 formed in the body 2. A heating resistor 5 for measuring the air flow rate and a temperature-sensitive resistor 6 for measuring the intake air temperature are provided inside the sub-passage 4. The heat-generating resistor 5 and the temperature-sensitive resistor 6 are arranged so as not to overlap with each other in the flow direction of the intake air 1 and are covered with a protective member 7 forming a part of the sub-passage 4. The heating resistor 5 and the temperature-sensitive resistor 6 are electrically connected to the support pins 8 and connected to the electronic circuit 10 via the lead wires 9. Electronic circuit 10
Is based on the output signals of the heating resistor 5 and the temperature-sensitive resistor 6,
It is configured to output a signal related to the air flow rate. The protection member 7 is fixed to a circuit module 11 on which the electronic circuit 10 is installed. FIG. 3 is a perspective view of a part when the protection member 7 is removed from the module 11 in which the heating resistor 5 and the temperature-sensitive resistor 6 are installed and viewed from an oblique direction. Also, FIG.
2 shows a partial external view of the protection member 7 alone viewed from an oblique direction.

FIG. 5 is a partial external view of the protection member 7 when inserted and fixed in the module 11 as viewed obliquely. As shown in FIG. 5, the protection member 7 is formed between the heating resistor 5 and the temperature-sensitive resistor 6 so as not to contact the heating resistor 5 and the temperature-sensitive resistor 6. Are integrally formed.

FIG. 6 shows a heating resistance type air flow measuring device in which a member 13 forming a sub-passage according to another embodiment is integrated with a circuit module 11. Member 1 forming sub-passage
Also in the case of the heating resistor 3 and the protection member 7 of the temperature-sensitive resistor 6, the partition plate 12 is integrally formed. FIG. 7 shows a member 1 forming a sub-passage which integrally forms a split plate 12
3 is a cross-sectional view of a portion where a heat flow line 14 when the intake air 1 flows into 3 is shown. FIG. 8 is a partial cross-sectional view showing the heat flow line 14 when the intake air 1 flows into the member 13 forming the sub-passage of the conventional product having no partition plate.
In the case where the partition plate 12 is not provided as shown in FIG. 8, the temperature-sensitive resistor 6 receives the influence of the heat generated by the heating resistor 5 and causes a measurement error in the detection of the air temperature, but as shown in FIG. If formed integrally with the protection member 7 or the member 13 forming the sub-passage, the measurement accuracy of air flow measurement can be improved without thermal interference between the temperature-sensitive resistor 6 and the heating resistor 5.

[0009]

According to the present invention, even if the heating resistor for measuring the air flow rate is installed on the upstream side of the intake air and the temperature sensing resistor for measuring the intake air temperature is installed on the downstream side, the temperature sensing resistor generates heat. Since the measurement error can be reduced without being affected by the heat of the resistor, the measurement accuracy of a device for measuring the flow rate of air taken into an automobile engine or the like can be improved.

[Brief description of the drawings]

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

FIG. 2 is a front view as viewed from the left side of FIG. 1;

FIG. 3 is a perspective view of a part in which a module in which a heating resistor and a temperature-sensitive resistor are installed is viewed from an oblique direction.

FIG. 4 is a perspective view of a part of the protection member unit having the partition plate integrated as viewed from an oblique direction.

FIG. 5 is a perspective view of a part viewed from an oblique direction when a single protective member having an integral partition plate is fixed to a module.

FIG. 6 is a cross-sectional view of a heating resistance type air flow measuring device in which a member forming a sub passage is integrated with a module in another embodiment.

FIG. 7 is a cross-sectional view of a portion showing a heat flow line when intake air flows into a member forming a sub-passage integrally forming a partition plate.

FIG. 8 is a cross-sectional view of a portion showing a heat flow line when intake air flows into a member forming a sub-passage of a conventional product.

[Explanation of symbols]

1 ... intake air, 2 ... body, 3 ... main passage, 4 ... sub passage,
5: heating resistor, 6: temperature-sensitive resistor, 7: protective member, 8:
Support pins, 9 lead wires, 10 electronic circuits, 11 circuit modules, 12 partition boards (walls).

Claims (3)

[Claims] A main passage forming an intake passage which is a passage for air introduced into the internal combustion engine; and a sub-passage for passing a part of air flowing through the main passage. Is a heating resistor type air flow measuring device having a heating resistor and a temperature sensing resistor, and comprising the heating resistor and an electronic circuit electrically connected to the temperature sensing resistor, wherein the heating resistor is And the temperature-sensitive resistor is arranged with a step so as not to overlap with the flow direction of air, and a wall or a partition plate between the heat-generating resistor and the temperature-sensitive resistor is parallel to the flow direction. A heating resistance type air flow measuring device characterized by being provided so as to be as follows. 2. A heating resistance type air flow measuring device according to claim 1, wherein said partition plate is formed integrally with a cap-shaped protection member for protecting said heating resistor and said temperature sensitive resistor. 3. The member according to claim 1, wherein the partition plate is formed integrally with a member forming a sub-passage having at least one bent portion, and the member holding the heating resistor and the temperature-sensitive resistor is formed integrally. When a member constituting a sub-passage is installed, the heating resistor and the temperature-sensitive resistor are located in the sub-passage, and the partition plate is provided between the heating resistor and the air. Flow measurement device.