JPS58113718A - Measuring apparatus for flow rate of gas - Google Patents

Abstract

PURPOSE:To improve the accuracy of the flow rate measurement and the responsiveness, by forming a supporting body for coil winding provided in a flow rate measuring tube in channel shape by removing a frame part of the upper stream side, to construct so that a flow of a fluid is hardly affected by the supporting body. CONSTITUTION:Each resistance wire 10-12 is supported by the first and the second supporting bodies 14, 15 and is arranged in a flow of inhaled air. Each body 14, 15 is made of an electric insulator such as ceramics or synthetic resin and is formed nearly in H shaped plate. The resistance wire 10 for an electric heater and the first temperature dependent resistance wire 11 affected by the heat of the heater 10 are wound around the first supporting body 14, to said two plate-like supporting bodies 14, 15. On this occasion, both wires 10, 11 are wound >= two times alternately in parallel and also closing to each other. Further, both ends of winding are connected to a copper foil on the surface of the body 14 and are connected to a measuring circuit through said foil.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas flow rate measuring device, for example, a device for measuring the intake air amount of an engine.

In a fuel injection type engine, it is necessary to accurately measure the intake air flow rate as a weight flow rate and adjust the fuel supply amount to an optimum amount commensurate with the intake air amount. As an intake air amount measuring device for this purpose, a resistance wire for an electric heater and eight temperature-dependent resistance wires are arranged in an appropriate relationship in the flow of intake air, and each of these resistances a! There is a known method that measures the amount of intake air using a signal from the engine. In this case, heat is added to the intake air by the electric heater resistance wire, and the resulting increase in humidity of the intake air is caused by the two temperature-dependent resistors #:
Therefore, it is detected. The relationship between the amount of heat added to the intake air and the resulting temperature rise necessarily changes depending on the weight flow rate of the intake air, and this is used to keep the intake air amount constant.

This intake air flow leakage device has the advantage of being small and simple in structure and capable of accurately regulating the flow rate. However, each resistance I! The big question is how to support it in the intake air flow.

In other words, pack 7 air often occurs in the engine, so the shock caused by this also reduces winter resistance.
There are dues to support each line of resistance so that you don't lose. In addition, in order to improve the accuracy and responsiveness of constant flow rate,
All about the amount of heat of resistance wire for electric heaters! It is extremely important that the temperature increase added to the Phm human air and the resulting intake air can be quickly detected by the eight temperature-dependent resistance lines.

In view of the above-mentioned points, the present invention has improved the support** of each resistance wire.The purpose is to prevent disconnection of each resistance wire and improve the accuracy and responsiveness of flow rate measurement. There is a particular thing.

According to the present invention, each resistor is wound around a support made of an insulating material so as to prevent wire breakage due to the flow of the gas to be measured and shock waves.

Furthermore, the electric heater resistor and the first temperature-dependent resistance wire that should be affected by the heat thereof are wound alternately one or more turns on the same support in close proximity to each other, and At an angle of 60° to 110° to the flow *! ＾To be ′& done. With this, the resistance wire for the heater
1k is transmitted continuously to the first temperature-dependent resistance line with high sensitivity.

In a preferred embodiment of the present invention, the support is constructed such that the influence of the heat capacity of the support is as small as possible, and the disturbance of the flow of the gas to be measured due to the installation and shape of the support is as intrusive as possible to the flow rate measurement. - the installation and structure of the support are selected accordingly;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments when applied to an engine intake air amount measuring device.

111th! At J, combustion air is supplied to the engine l via the air cleaner 3 and the intake conduit 8 to the intake valve -
is inhaled by opening the valve. On the other hand, fuel is injected and supplied from an electromagnetic fuel injection valve bb installed in the four suction pipes 8. The flow rate of the intake air is controlled by a throttle valve 6 provided at the intake conduit, and the opening period of the injection valve is controlled by the amount of fuel #1lIII11 unit).

In order to measure the intake air flow rate, a fitmKIL amount measuring tube 8 is arranged above the throttle valve 6 inside the intake conduit 8,
On the upstream side K11, a rectifying grid 9 having a honeycomb shape, for example, is installed to rectify the flow of air. This causes a certain proportion of the intake air to pass into the pipe 8. The measuring tube 8 is the support 81't' suction conduit 3
is maintained.

The flow measuring device according to the present invention determines the amount of intake air km from the amount of air passing through the measuring pipe a, and includes a sensor section 8 and a measuring circuit 18. It is arranged inside the measuring tube 8 mentioned above.

The above sensor part 1Ifi is a resistor for the electric heater that adds heat to the intake air! l! 1O, and the first whose resistance value changes depending on the temperature.
The temperature-dependent resistance of the first snow m1ll, 1 m is included. First temperature dependent resistance m1ll lti electric heater resistance [10
, 6, etc., while the third temperature-dependent resistor gi1m is connected to the resistance wire for the electric heater so as to detect the temperature of the intake air when it is not receiving the heat. Each arrangement position is selected. The electric heater resistor @10 is made of platinum resistance wire, for example, and is 111
, the third temperature-dependent resistor gill, 1m are made of, for example, platinum wire, platinum alloy wire, tungsten wire, etc., having the same temperature-resistance characteristics.

The measurement circuit Im is connected to each of the above-mentioned resistors 4110 to 1m,
While applying a voltage to each of them, the amount of intake air is calculated based on the respective spring signals. Is the calculation result controlled by the unit? The fuel injection amount is controlled manually by Km.

When power is supplied to the electric heater resistance wire 10 to generate heat, the first. A temperature rise (temperature difference occurs) due to the heating of the intake air between the third temperature-dependent resistance l[1!11°1m. Measurement@Circuit 11aFor example, the amount of heat generated by the electric heater resistance wire IG (amount of power supplied) t? is controlled so that the amount of temperature rise is constant, and the amount of power supplied is The intake air amount is calculated from the following.The specific structure of the measurement path 11 is shown in, for example, Japanese Unexamined Patent Publication No. 116-6M116, so the explanation thereof will be omitted here.

In the above-mentioned intake air amount measuring device, according to the present invention, the d-sen section 8 is constructed as follows.

Okay, figure 31 and j! FIG. 1 shows a first embodiment of the present invention, in which each resistance wire lO~1m is supported by an eleventh third support 14, 16 and placed in the flow of intake air. Each of the supports 14 and 16 is made of an electrically insulating material such as ivy or synthetic resin, and is formed into a substantially H-shaped plate. With respect to these three plate-shaped supports, the electric heater resistor 4110 and the first temperature-dependent resistance wire 11 to be subjected to the heat influence tube are both wound around the first support l-.

In that case, both 4110 and 11 are wound parallel to each other and close to each other, alternately, with a number of turns equal to or greater than 11 (in the figure, a square winding). -IK! on the surface of the first support 14 at both ends of the winding! I was connected and measured through the tube.
It is connected to Route II (Fig. 1) and III&.

In the figure, only the steel foil lam and lob to which one end of the resistance wire 16 and the other end of the resistance wire 11 are connected are shown.
A steel foil to which one end of the resistance wire 10 is connected and a #ii foil to which the other end of the resistance wire 10 is connected are provided on the opposite side from the steel foils xo* and lxb.

The eighth temperature-dependent resistor 911tj is wound individually on the third support 16 and is connected to the measuring circuit 13 via @1illa, llb.

The 11th first support is held inside the measuring tube 8 in a state parallel to the flow of intake air). Moreover, in this case, the resistance wire 101 on the first support body
11 is arranged such that each spring portion faces the intake air flow (4) at an angle f0. This angle - is 60
It is set within the range of 0 to 110'. This results in electric heating with overnight resistance line lO and JIIlf) IIA degree-dependent resistance line 1
1 means 1 from the upstream side to the downstream axis along the air flow.
The 1st spring of 11 people, the 1st spring of 111, the 1mth volume of IIJiif, the 3rd spring of the afterword, etc. are arranged alternately.

The third support member 1jitj is held with a predetermined opening from the first support member l-, so that the heat from the electric heater resistance wire 1G does not act on the eighth temperature-dependent resistance wire 11. It will be done. The third support may be placed upstream of the first support depending on the case.

According to the senna section having the above configuration, the resistance koji for electric heater 10
and the first temperature-dependent resistance line 11. ! : are wrapped around the first support 14 in close proximity to each other, so that
The intake air that comes into contact with the first temperature-dependent resistance wire 11 can be effectively heated by the electric heater resistance wire 10, thereby reducing heat loss. Further, the temperature of the heated large intake air can be quickly detected by the first temperature-dependent resistance line 11. Therefore, accuracy and responsiveness of flow rate measurement are improved.

In addition, the above two [1G, Il111 or more are wound alternately, and the spring is also applied to the flow of intake air.
The first spring of 1O, the first spring of 1lill, the 8th spring of 1111O, the S turn of wire 11, etc. are arranged alternately in this order, so the heat in each turn am of the resistance wire 10 for electric heater acts on each spring portion of the first temperature-dependent resistance line 11 on the downstream side thereof. As a result, the sensitivity of flow rate measurement is improved and more accurate and flow rate measurement becomes possible.

Now, the amount of heat generated by the electric heater resistor Ii[1Of)14I is rl, and the amount of air temperature rise due to it is Δ! Assuming that the air intake amount is G (g/g), the following equation holds true when the above-mentioned two lines are 10°11 per roll.

I think ・ΔChi F/G (However, 8 companies are fixed) -(1)
Therefore, while the temperature rise ΔTq in the first spring of the first temperature dependent resistance 1[11 is expressed by the above equation (1), both lines 10.
If it is constructed as described above as volume 11 WIf vr, the temperature rise at the nth spring of the eel is equal to Mu·ΔT, which is the sum of all the temperature rises at its upstream price.

Therefore, if we take the relationship 1-1 between ΔT, P, and G in this case, 1≦・karasu (l ganryo i+...juchi) ΔT=Kou 1
-P/G, and from this the following equation (2) is established.

L, ・ΔT−g±=P/u ・・・・・・・・
・(g) In other words, compared to the case where only the heat of the resistance wire for the electric heater is applied to 181 (1・ΔT'=P/G), a temperature increase of 78 times (n+1) can be obtained. Therefore, the sensitivity is improved accordingly.

According to part 8, each resistance! l1110~11 [
By wrapping it around the support l-11M and placing it in the air flow, the resistance is lower than when each resistance tube is installed alone.
Of course, the degree of illumination is improved. Therefore, the reliability of the wire and senna parts is greatly improved by preventing each resistance wire from breaking by 1 m due to vibration or impact pressure from the engine's pack 7 tires.

In addition, the support 14.16Fi has a U-shape, and the flow is less disturbed by the support and has a cedar-like shape, which improves measurement accuracy.

Figures 3 and 8B illustrate the @;S embodiment of the present invention. This embodiment includes a support 14.1h and each resistor 11i11G~l! which is wound around the support 14.1h. The first *! point is to minimize the contact area with the tube as much as possible! This is different from Example II.

At each support 14.16, a rod-shaped base 141°15
On both sides of 1, that is, the part that becomes the folded part of the resistance wire to be noticed, there are one wire protruding to each of the bases 141 and 161, one protruding to the other side, and the base $141,1. ! l
141, I
II will be sold separately. And each resistance wire 1G-1m
a Each protrusion 141.1 i so' is wrapped around the corresponding support 14, li in contact with the tip surface, and the base 141
From ゜161 to ttii-good condition.

By reducing the contact m between each resistor and the support with such a configuration, the heat of the electric heater resistor 1110 will be less likely to escape to the support. Therefore, responsiveness is improved. Also,
By reducing the contact area between each resistance wire and the support, the dirt and each resistance wire come into indirect contact through the dirt due to the adhesion of dirt. By reducing the increase in I#I, the rate of change in the amount of heat transferred from the electric heater to the thermometer becomes smaller.

In addition, both parts of the support body 14 (15) are marked as shown in the figure.
By providing $9144 of l& at predetermined intervals and winding the resistance wire through these grooves, the winding of the resistance wire becomes easy and the variation in winding can be eliminated.
It is also useful because it can prevent the resistance wire from shifting and improve its durability.

At this peak, ti electric heater 1O111I on the same support.
Since the temperature-dependent resistor 11 of 1 is wound around, some of the heat from the electric heater is taken away by the support, but the heat is taken away by the support and is transferred to the first temperature-dependent resistor 11 via the hot wire support. The accuracy of measuring the heat loss tin of the electric heater is greatly improved.

In addition, since the structure in which the electric heater Io and the first temperature-dependent resistor 11 are wound around the same support, the electric heater and the first temperature-dependent resistor #i pole can be provided close to each other, which increases the amount of air. The responsiveness/fi of the measuring device is greatly improved.

In addition, the structure is resistant to shock waves such as a puncture fire, making it possible to greatly improve reliability.

Furthermore, in the present invention, the electric heater, the 11th and 8th temperature dependent resistors are wound around the female part 11th support body, and the structure is such that there is no support body inside or upstream of the frame. Disturbance of the flow caused by the support becomes extremely small, especially in the transition region of the fluid to be measured.

Furthermore, in the present invention, the support 14 is disposed in the gas to be measured so that the electrically heated part 10 and the first temperature dependent resistor 11 are opposed to the flow at an angle of 60° to 1110''. The heat of the wire is at least 5
Sensitivity is improved (ΔTu
p) can be measured.

Further, in the third aspect of the present invention, by providing the supports 16 and 15 with a protruding cedar shape, the influence of the heat capacity of the supports can be reduced and the self-responsiveness can be improved. Furthermore, in the third aspect of the present invention, grooves are provided in the support body 14,16. As a result, it is possible to reduce variations during manufacturing, and it is also possible to prevent the position of the resistance wire from shifting due to shooting waves or pack fire waves, thereby improving durability.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of an engine equipped with the device of the present invention, #lI
Figure 8B is a perspective view showing the first embodiment of the present invention.
The figure is a front view of a part of it, and the 8th figure is the 1I part of the device of the present invention.
A perspective view of the JII example, Figure 8B, a part of the Ikko @ mountain view, Figure 4m (11), (b) a view equivalent to Figure si showing a modification of the example of the FIG. 6 is a normal Ig diagram of the support of FIG. 33. $...Flow rate constant tube, 10-...Resistance wire for electric heater. 11.11-・11th third temperature dependent resistance line, 1-11
M-... 1st. Sth support, 14! , 16m - ridge, 144 - groove. Attorney Takashi Okabe

Claims (1)

[Scope of Claims] (1) A short-circuit between the flow measuring tube through which the gas to be measured flows, the first support made of an electrical insulating material provided in the flow leakage tube, and the support of the recorder turtle 1. an electric heater river resistance wire and a first temperature-dependent resistance wire that are alternately wound two or more turns in close proximity to each other so as not to prevent the snow from falling; and a second temperature-dependent resistance wire that is wound around the snow collecting support; In the gas flow rate measurement including a measurement circuit for applying a voltage to the electric heater resistance editing 1 and the eighth m-degree dependent resistance wire to obtain the flow rate of the gas to be measured, ikk,
A gas flow measuring device characterized in that it has a U-shape with no upper tit shaft frame shaft tube portion, and has an armor-like structure in which the fluid flow is reflected by the third support member. (Dew) The electric heating resistor KIIA and the first temperature-dependent resistance wire wound around the first support are aligned once with the flow of the gas to be measured at an angle of 60' to Igo'. A gas flow rate measuring device according to claim 1 or 8, characterized in that: (8) The first and second supports have protrusions t that are partially in contact with the respective resistance wires wound thereon, and each of the resistors M
2. The gas flow rate measuring device according to claim 1, wherein the protrusion is in contact with the corresponding support. (4) A measuring device on which the eleventh and eighth supports are wound.