JP3784873B2 - Valve opening sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a valve opening sensor that detects the opening of a valve that controls the flow rate of a medium that passes through a flow path. For example, a valve that detects the absolute opening of a throttle valve of a gasoline engine in a non-contact manner. The present invention relates to an opening sensor.
[0002]
[Prior art]
In general, throttle valve opening detection information in a gasoline engine is used for air-fuel ratio correction at the time of a transient response and detection of an unloaded state of the engine (detection of the fully closed state of the throttle valve).
[0003]
By the way, the detection of the no-load state of the gasoline engine is performed by setting a very small throttle opening close to the fully closed state as a determination level and comparing the determination level with the detection value of the valve opening sensor. When it falls below the judgment level, it is judged that there is no load. However, the shaft that supports the throttle valve and the rotary shaft of the potentiometer are generally mechanically connected, and the output voltage value of the potentiometer when the valve is fully closed needs to be adjusted to a predetermined value. The mounting position of the potentiometer is configured to be movable.
[0004]
In this configuration, the opening degree of the throttle valve and the rotation angle of the potentiometer may change relatively, and the detection characteristics become unstable due to changes over time and the initial assembly position. However, it was difficult to detect the minute and absolute valve opening.
[0005]
In order to solve this problem, Japanese Patent Application Laid-Open No. 63-503082 teaches that the minimum value of the voltage output from the potentiometer is updated and learned when the throttle valve is fully closed or fully opened. Has been proposed.
[0006]
[Problems to be solved by the invention]
However, in the conventional valve opening sensor as described above, electrical noise is always superimposed on the opening detection information from the potentiometer, and an erroneous voltage value is generated when the valve is fully closed due to the mixing of this electrical noise. The problem of learning is easily anticipated.
[0007]
In some cases, the engine is operated only in a low temperature state in which a well-known fast idle mechanism is operated, for example, when the throttle is fully closed during a learning period (generally, a period from when the ignition switch is turned on to when it is turned off). In some cases, there is a problem of losing the opportunity to learn.
[0008]
Furthermore, the prior art has a drawback that the true valve opening (absolute valve opening) is not detected. In other words, the well-known butterfly type air flow rate adjusting mechanism has a “galling” (this “galling”) generated by contact between the valve bore surface and the valve material when fully closed. In order to prevent the operational feeling of the mechanism from deteriorating), it is configured to be fully closed with a predetermined minute gap.
[0009]
Since this minute gap is held by an adjustable, for example, screwed stopper or the like, the minute gap changes depending on wear or deformation of the stopper with time, biting of dust, or the like. Therefore, the valve opening sensor of the prior art can only detect the relative valve opening based on the changing gap, and it is impossible in principle to detect the absolute opening.
[0010]
The present invention has been proposed to solve the above-described conventional problems, and an object of the present invention is to provide a valve opening sensor that can detect the absolute opening of the valve and improve the detection accuracy. is there.
[0011]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve the object, a valve opening sensor according to the present invention has the following configuration. That is,
In the valve opening sensor that detects the opening of the valve that controls the flow rate of the non-conductive medium,
In the flow path of the medium in which the valve is provided, whereas disposed side with respect to the valve, and transmitting means for outputting an electromagnetic wave,
Receiving means for being disposed on the other side, to receive the electromagnetic wave output from the transmitting means to said valve,
On the basis of the electromagnetic waves received by the receiving means, it comprises a detection means for detecting an opening degree of the valve,
The valve is composed of a conductor that shields electromagnetic waves output from the transmitting means,
The detection means detects the opening degree of the valve based on the electric field strength of the electromagnetic wave that changes according to the opening degree of the valve .
[0012]
As described above, in the present invention, when detecting the opening degree of the valve that controls the flow rate of the non-conductive medium, in the flow path of the medium in which the valve is provided, the valve is output from one side. The electromagnetic wave is received on the other side, and the opening degree of the valve is detected based on the electric field strength of the electromagnetic wave that changes according to the opening degree of the conductive valve that shields the electromagnetic wave .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0014]
<First Embodiment>
FIG. 1 is a sectional view showing a mechanism around a throttle valve according to the first embodiment of the present invention. In FIG. 1, a throttle valve 11 is provided in the middle of an intake pipe 10 that becomes an intake air flow path of a gasoline engine in an automobile or the like. The intake pipe 10 is formed in a cylindrical shape on its inner surface, and is formed by aluminum die casting or the like. Molded. The intake pipe 10 is provided with a shaft 12 that penetrates the center of the cross section and is connected to an unillustrated accelerator pedal by a wire or the like, and the throttle valve 11 has a cross-sectional shape orthogonal to the air flow direction in the intake pipe 10. And is provided to be rotatable with the rotation of the shaft 12. The intake pipe 10 is opened and closed as the throttle valve 11 rotates.
[0015]
The intake air of the gasoline engine flows into the intake pipe 10 from one side (upstream side) of the throttle valve 11, and the air flow of the intake pipe 10 is adjusted by the opening of the throttle valve 11 to control the generated output of the gasoline engine. Has been.
[0016]
Inside the intake pipe 10, a transmission antenna 101 mechanically connected to an intake air flow path upstream or downstream with respect to the throttle valve 11 is disposed. The transmission antenna 101 is electrically insulated. It is provided inside the intake pipe 10 via a connection member 101a made of a conductive material.
[0017]
The connection member 101a is electrically connected to the transmission antenna 101, penetrates from the inside of the intake pipe 10 to the outside, and the tip thereof is connected to the transmission / reception circuit 100 outside.
[0018]
Similarly to the transmission antenna 101, a mechanically connected reception antenna 102 is disposed in the intake air flow path on the side opposite to the transmission antenna 101 via the throttle valve 11 inside the intake pipe 10. The receiving antenna 102 is provided inside the intake pipe 10 via a connecting member 102a made of an electrically conductive material that is electrically insulated.
[0019]
The connection member 102a is electrically connected to the reception antenna 102, penetrates from the inside of the intake pipe 10 to the outside, and the tip thereof is connected to the transmission / reception circuit 100 outside.
[0020]
The transmission / reception circuit 100 is connected to a fuel injection control circuit (not shown) via a lead wire extending outside, and is supplied with power from the fuel injection control circuit and transmits a valve opening degree detection signal. .
[0021]
FIG. 2 is a detailed circuit diagram of the transmission / reception circuit 100 shown in FIG. In FIG. 2, the transmission / reception circuit 100 includes an oscillation circuit having an inverter 110, a resistor 115, capacitors 113 and 114, and an oscillator 112, and a coil-shaped transmission from the oscillation circuit via an inverter 111, a resistor 116 and a capacitor 117. An antenna 101 is connected. The transmission / reception circuit 100 includes a linear amplifier including a capacitor 120, resistors 121 and 122, and an inverter 123. The reception antenna 102 is formed in a coil shape like the transmission antenna 101, and one end thereof is connected to the linear amplifier. Has been. The output of the linear amplifier is connected to an amplifier circuit composed of a capacitor 126, a resistor 127, and an inverter 128 via a filter composed of a vibrator 124 and a resistor 125. The output of the inverter 128 is input to the detection circuit 130, and the output signal V 0 is output from the detection circuit 130 via the lead wire 103.
[0022]
<Opening detection principle of valve opening sensor>
Next, the opening detection principle of the valve opening sensor according to this embodiment will be described. FIG. 3 is a diagram showing the relationship between the valve rotation angle and the output voltage V0 from the detection circuit.
[0023]
The transmission antenna 101 is applied with a high frequency (several tens of MHz or more) by the oscillation circuit of the transmission / reception circuit 100, and generates an electromagnetic field with a predetermined output at a predetermined frequency in the internal space of the intake pipe 10. Since the intake pipe 10 and the throttle valve 11 are made of an electrical conductor, when the throttle valve 11 is fully closed and there is no gap with respect to the inner surface of the intake pipe, that is, the throttle is fully closed, the receiving antenna is caused by the electromagnetic shielding effect. The magnitude of the electromagnetic field acting on 102 is approximately zero.
[0024]
On the other hand, when the shaft 12 rotates and a predetermined opening area is generated between the intake pipe 10 and the throttle valve 11, the strength of the electromagnetic field leaking toward the receiving antenna 102 in proportion to the size of the opening area. Will increase. The receiving antenna 102 generates a voltage according to the magnitude of the leaked electromagnetic field and amplifies and detects this voltage to obtain a stable output voltage V0.
[0025]
As described above, the valve opening sensor according to the present embodiment obtains the output voltage according to the opening area of the intake air flow path by the intake pipe 10 and the throttle valve 11, for example, an opening as shown in FIG. 3. The valve rotation angle based on the area can be detected.
[0026]
Second Embodiment
Next, the valve opening degree sensor of 2nd Embodiment which concerns on this invention is demonstrated. FIG. 4 is a sectional view showing a mechanism around a throttle valve according to the second embodiment of the present invention. In the second embodiment, members corresponding to those in the first embodiment are denoted by the same reference numerals and redundant description is omitted, and only differences from the first embodiment will be described.
[0027]
In FIG. 4, an electromagnetic shield 401 made of a metal mesh member or the like is disposed in the intake air flow path on the side opposite to the transmission antenna 101 of the throttle valve 11 inside the intake pipe 10, and similarly, the throttle valve An electromagnetic shield 402 made of a metal mesh member or the like is disposed in the intake air flow path on the opposite side to the eleven reception antennas 102.
[0028]
According to the second embodiment, in addition to the effect of the first embodiment, when the throttle valve 11 is in the fully closed state, the amount of displacement of the fully closed position caused by electromagnetic waves that leak around the outer wall portion of the intake pipe 10 ( Detection error) can be reduced.
[0029]
<Third Embodiment>
Next, a valve opening sensor according to a third embodiment of the present invention will be described. FIG. 5 is a cross-sectional view showing a mechanism around a throttle valve according to a third embodiment of the present invention. In the third embodiment, members corresponding to those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. Only differences from the first embodiment will be described.
[0030]
In FIG. 5, a mechanically connected sub-reception antenna 501 is disposed in the intake air flow path on the side opposite to the transmission antenna 101 of the throttle valve 11 inside the intake pipe 10. Reference numeral 501 is provided inside the intake pipe 10 via a connection member 502 made of an electrically conductive material that is electrically insulated.
[0031]
The connection member 502 is electrically connected to the sub reception antenna 501, penetrates from the inside of the intake pipe 10 toward the outside, and the tip thereof is connected to the transmission / reception circuit 100 on the outside.
[0032]
According to the third embodiment, in addition to the effect of the first embodiment, the electric field strength at the time of transmission of the transmission antenna 101 is increased by the electric field strength at the time of reception of the sub reception antenna 501 regardless of the opening degree of the throttle valve 11. Since it is possible to monitor, by controlling the output of the oscillation circuit of the transmission / reception circuit 100 so that the transmission output of the transmission antenna 101 becomes constant, fluctuations in the oscillation output due to temperature changes of the oscillation circuit of the transmission / reception circuit 100 can be prevented. Sensitivity fluctuation can be reduced to improve detection accuracy.
[0033]
<Effect of this embodiment>
As described above, according to the valve opening sensor of the present embodiment, since the detected output voltage becomes zero when the throttle valve 11 is in the fully closed state, there is a minute amount between the intake pipe 10 and the throttle valve 11. There is no need to provide a gap, the absolute valve opening can be detected, and there is no need to learn the output voltage value using a sensor as in the prior art, and there is a threaded stopper that holds the throttle valve in the fully closed position. There is an effect that the sensor output with respect to the valve opening does not fluctuate even if the shift of the fully closed position due to wear or the like occurs.
[0034]
Since there are no movable parts compared to the conventional potentiometer, the life and reliability can be improved.
[0035]
It should be noted that the present invention can be applied to a modified or changed embodiment described above without departing from the spirit of the present invention.
[0036]
In the first to third embodiments, the coiled conductive wires are used as the transmitting antenna and the receiving antenna. However, any form such as a plate type or a rod type can be applied to these antennas. Further, the transmission / reception circuit is not limited to the one shown in FIG. 2, and any circuit can be used as long as it has a similar function. Furthermore, since the phase relationship between the transmission wave and the reception wave changes based on the valve opening, this phase relationship may be associated with the valve opening. In addition to electromagnetic waves, infrared rays may be used as those transmitted from the transmission antenna.
[0037]
In addition, adjustment of the arrangement position and size of the transmission antenna and the reception antenna, etc., or change of the cross-sectional shape of the inner surface of the intake pipe 10 to cause reflection of electromagnetic waves, thereby making the detection characteristic for the valve opening predetermined predetermined You may make it set to a characteristic.
[0038]
【The invention's effect】
As described above, according to the valve opening sensor of the present invention, when detecting the opening of the valve that controls the flow rate of the non-conductive medium, the valve in the flow path of the medium provided with the valve On the other hand, the electromagnetic wave output from one side is received on the other side, and the opening degree of the valve is detected based on the electric field strength of the electromagnetic wave that changes according to the opening degree of the conductive valve that shields the electromagnetic wave . The absolute opening can be detected, and the detection accuracy can be improved.
[0039]
[Brief description of the drawings]
FIG. 1 is a sectional view showing a mechanism around a throttle valve according to a first embodiment of the present invention.
FIG. 2 is a detailed circuit diagram of the transmission / reception circuit 100 shown in FIG.
FIG. 3 is a diagram showing a relationship between a valve rotation angle and an output voltage V0 from a detection circuit.
FIG. 4 is a sectional view showing a mechanism around a throttle valve according to a second embodiment of the present invention.
FIG. 5 is a sectional view showing a mechanism around a throttle valve according to a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Intake pipe 11 ... Throttle valve 12 ... Shaft 100 ... Transmission / reception apparatus 101 ... Transmission antenna 102 ... Reception antenna 401, 402 ... Metal mesh member 501 ... Sub reception antenna

Claims (6)

In the valve opening sensor that detects the opening of the valve that controls the flow rate of the non-conductive medium,
In the flow path of the medium in which the valve is provided, whereas disposed side with respect to the valve, and transmitting means for outputting an electromagnetic wave,
Receiving means for being disposed on the other side, to receive the electromagnetic wave output from the transmitting means to said valve,
On the basis of the electromagnetic waves received by the receiving means, it comprises a detection means for detecting an opening degree of the valve,
The valve is composed of a conductor that shields electromagnetic waves output from the transmitting means,
The valve opening sensor is characterized in that the detection means detects the valve opening based on the electric field strength of an electromagnetic wave that changes in accordance with the valve opening.   2. The transmission unit according to claim 1, wherein the transmission unit is a transmission antenna disposed on the upstream side of the valve, and the reception unit is a reception antenna disposed on the downstream side of the valve. Valve opening sensor.   The said transmission means is a transmission antenna arrange | positioned in the downstream of the said valve | bulb, and the said reception means is a reception antenna arrange | positioned in the upstream of the said valve | bulb. Valve opening sensor.   The valve opening sensor according to claim 1, further comprising a sub-reception antenna disposed in proximity to the transmission means. On one side and the other side of the valve, according to claim 1 wherein the arrangement position of the valve the transmission means and receiving means, characterized in that a shielding means for shielding the electromagnetic waves on the other side Valve opening sensor. It said detecting means, the valve position sensor according to any of claims 1 to 5, characterized in that by converting the electromagnetic wave received by the receiving means into a voltage to detect an opening degree of the valve.

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