JPH0442767Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a sensor for detecting the mixing ratio of a liquid mixture of petroleum-based fuel and alcohol as a fuel for an internal combustion engine.

[Prior Art] Petroleum resources, which are the driving fuel for internal combustion engines, are destined to steadily become depleted in the future. As one of the countermeasures, plans are being advanced in various places to manufacture alcohol using raw materials such as plants, coal, and natural gas, and to mix it with petroleum resources such as gasoline in order to suppress the consumption of petroleum resources as much as possible. It is being

In order to maximize the combustion efficiency of the internal combustion engine that uses the mixed liquid as fuel and to minimize the amount of harmful substances in the combustion exhaust gas, the ratio of air to fuel supplied to the internal combustion engine and the ignition timing are strictly controlled. There is a need to. Naturally, these control conditions must be changed depending on the mixing ratio of the mixed liquid.

Therefore, in recent years, a light-emitting element is placed on one end surface of a transparent body whose outer surface is in contact with the mixed liquid supplied to the internal combustion engine, and a measuring light-receiving element is placed facing each other on the other end surface.
As the composition of the mixed liquid changes, the critical angle at the part of the transparent body that comes into contact with the liquid mixture changes.By measuring the amount of light that has passed through the transparent body, it is possible to measure the amount of light that is supplied to the internal combustion engine. A mixture ratio sensor has been proposed to detect the mixture ratio of a liquid mixture.

The light emitting body of this conventional mixture ratio sensor is
As shown in FIGS. 3 and 4, a flat light emitting diode 101 was used.

[Problems to be solved by the invention] However, the light emitting portion 102 of the conventional flat light emitting diode 101 emits light not only from the side on which the transparent body 103 is disposed, but also from the side thereof.
Since the light emitted from the side surface is reflected by the base 104 that supports the light emitting portion and radiates toward the transparent body 103, the apparent light emitting area of the light emitting diode 101 increases. Therefore, the area of light that is totally reflected within the transparent body 103 also increases, and the light emitting diode 1
The light emitted from 01 is more likely to hit the member 105 that supports the transparent body 103. Furthermore, when assembling the mixture ratio sensor, if the assembly position of the light emitting diode 101 is shifted from the center axis of the transparent body 103, the apparent light emitting area of the light emitting diode 101 is large.
The area of light that is totally reflected within the transparent body 103 is the area of the light that is totally reflected within the transparent body 1
It becomes easier to hang onto the member 105 that supports 03. When the light hits the member 105 that supports the transparent body 103 within the measurement range of the mixed liquid as shown in FIG. As a result, the mixing ratio of the mixed liquid cannot be detected accurately. Note that the solid line B in FIG. 5 represents the change in the amount of light received by the measurement light-receiving element 106 when the light totally reflected within the light-transmitting body 103 does not hit the member 105 that supports the light-transmitting body 103. It shows.

For this reason, it is possible to improve the assembly accuracy of the light emitting diode 101, and to improve the assembly accuracy of the light emitting diode 101.
Light-emitting diode 10 by increasing the light-receiving area of 06
Although the light emitting area of No. 1 has been made relatively small, both of these methods have led to an increase in production costs.

This invention was made in view of the above circumstances,
The purpose is to provide an alcohol-mixed fuel mixture ratio sensor that brings the light source of the luminous body closer to a point light source and can keep production costs low.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a transparent body having at least one side in contact with a mixed liquid of petroleum-based fuel and alcohol, and a transparent body disposed on one end surface of the transparent body. a light-emitting element arranged on the other end surface of the transparent body,
comprising a measuring light receiving element that measures the amount of light emitted from the light emitting element and passing through the light transmitting body;
The mixing ratio of the mixed liquid is determined by the value measured by the measuring light-receiving element by utilizing the fact that the critical angle at the part of the transparent body that comes into contact with the mixed liquid changes as the composition of the mixed liquid changes. In the alcohol mixed fuel mixture ratio sensor for detecting alcohol mixed fuel, the technical means is to coat the light emitting element and control the size of the light emitting area of the light emitting element.

[Function] In the mixture ratio sensor with the above configuration, among the light emitted from the light emitting element, the light enters from one end surface of the light transmitting body, and the light that passes through the light transmitting body is emitted to the measurement light receiving element. The amount of light received is detected by the measuring light receiving element.

Since the amount of light passing through this transparent body changes depending on the mixing ratio of the liquid mixture, it functions as a mixing ratio sensor by checking the amount of light received by the measuring light receiving element.

On the other hand, by coating the light-emitting element and controlling the size of the light-emitting area of the light-emitting element, the light source of the light-emitting element can be made arbitrarily small, which reduces the area of light that forms the critical angle within the light-transmitting body. Therefore, the light emitted from the light emitter is less likely to hit the member supporting the transparent body. As a result, even if the installation position of the light emitting body deviates from the center axis of the light transmitting body when assembling the mixture ratio sensor, the position of total reflection within the light transmitting body is unlikely to hit the member that supports the light transmitting body. Even if the assembly accuracy of the light emitting diode is lowered than before, or the light-receiving area of the light-transmitting body or measurement light-receiving element is made smaller than before, the mixing ratio of the mixed liquid can be detected accurately.

[Effect of the invention] By making the light source of the light emitting element arbitrarily small, it is possible to mix the liquid mixture even if the assembly accuracy of the light emitting element is reduced or the light receiving area of the light transmitting body or measurement light receiving element is reduced. Since the ratio can be detected accurately, the production cost of the mixture ratio sensor can be kept low.

[Example] Next, the alcohol mixed fuel mixture ratio sensor of the present invention will be described based on an example shown in the drawings.

FIG. 1 shows a side sectional view of a mixing ratio sensor for gasoline, which is a petroleum-based fuel, and alcohol.

This mixture ratio sensor 1 includes a case 2, a light emitting section 3,
It is roughly divided into a light transmitting body 4 and a measuring light receiving section 5.

The case 2 is in the form of a cylindrical container and is made of metal or resin. This case 2 has a mounting hole 21 formed through the end faces of both cylinders. A light emitting section 3, a transparent body 4, and a measuring light receiving section 5 are sequentially attached to the mounting hole 21 from one end. There is an internal space 22 inside the case 2.
is formed. This internal space 22 forms a passage for the mixed liquid for measurement and communicates with an inlet joint 23 and an outlet joint 24 for the mixed liquid for measurement provided on the peripheral wall of the case 2 . In addition, an O-ring 2 is attached to the case 2 that supports the outer periphery of the transparent body 4.
An annular groove 26 is formed in which the O-rings 5 are disposed, respectively, and the O-ring 25 prevents the mixed liquid for measurement flowing through the inner space 22 from flowing out through the attachment hole 21.

The light emitting unit 3 includes a light emitting unit case 33 consisting of a cylindrical measuring body 31 and a bottom plate portion 32 formed at one end of the measuring body 31, and a sealing glass 34 attached to the other end of the measuring body 31. , a light emitting diode 3 which is a light emitting element
5, and a compensation photodiode 36 for temperature compensation. As shown in FIG. 2, this light-emitting diode 35 includes a flat light-emitting portion 35a made of a combination of a P-type semiconductor and an N-type semiconductor that emits light when a voltage is applied, and a light-emitting portion 35a passing through the light-emitting portion 35a. positive and negative electrodes 35b, 35c for
It consists of a base 35d on which these are mounted.
The electrode 35b on the side of the light-emitting diode 35 on which the light-transmitting body 4 is disposed is coated on the outer periphery of the surface of the light-emitting part 35a on the side on which the light-transmitting body 4 is disposed. The light-emitting area of the surface on which No. 4 is arranged is made small. In addition, a light-absorbing black resin coating 35e is applied to the surface of the base 35d of the light-emitting diode 35 on the side where the transparent body 4 is disposed, and the light emitted from the side surface of the light-emitting portion 35a is coated with a coating 35e made of black resin. This prevents the light from being reflected on the base 35d and radiating toward the transparent body 4. As a result, the light emitted to the base 35d is absorbed by the resin coating 35e, and no light is emitted to the transparent body 4 side, so that the apparent light source of the light emitting diode 35 can be made smaller. In the light emitting unit 3 configured in this way, the sealing glass 34 is the transparent body 4.
is attached to one end of the case 2 so that the side body 31 is fitted into the attachment hole 21 of the case 2 .

The light-transmitting body 4 has a rod shape made of optical glass, acrylic resin, etc., and is arranged in the internal space 22, and has an outer circumferential surface 41 that comes into contact with the mixed liquid for measurement, and an entrance surface 42 on the side where the light-emitting part 3 is arranged. and a radiation surface 43 that is opposite to the incidence surface 42 and emits the light incident from the incidence surface 42 .

The measuring light receiving section 5 includes a light receiving section case 53 which is made up of a cylindrical side body 51 having a slightly larger diameter than the light emitting section 3 and a bottom plate section 52 formed at one end of the side body 51.
, a sealing glass 54 attached to the other end of the side body 51, and a measuring photodiode 55 which is a measuring light-receiving element that measures the amount of light incident through the sealing glass 54. Further, the measurement photodiode 55 outputs a voltage according to the amount of light received, and is attached to the bottom plate portion 52 so that almost the entire surface inside the side body 51 serves as a light-receiving surface. The measuring light receiving section 5 configured in this way is attached to the other side of the case 2 such that the sealing glass 54 faces the radiation surface 43 side of the light transmitting body 4 and the side body 51 fits into the mounting hole of the case 2. attached to the end.

As shown above, the present invention has three light emitting diodes.
Since the light emitting area (light source) in step 5 can be made arbitrarily small by coating with electrodes or resin coating, the area of light that forms the critical angle within the light-transmitting body becomes smaller, and the light emitted from the light-emitting body is reduced by that amount. It becomes difficult for light to hit the member that supports the transparent body. This may reduce the assembly accuracy of the light emitting element,
Even if the light-receiving area of the light-transmitting body or measurement light-receiving element is small, the mixing ratio of the mixed liquid can be accurately detected.
The production cost of the mixture ratio sensor can be kept low.

In addition, α shown in the figure indicates the part where the light incident on the incident surface 42 is totally reflected when the alcohol is 100% at a certain predetermined temperature, and β is the part where the light incident on the incident surface 42 is totally reflected when the alcohol is 100% at a certain predetermined temperature. It shows a portion where the light incident from the entrance surface 42 undergoes total reflection.

In addition, in the above embodiment, an example was shown in which the optical axis of the light emitting body was provided parallel to the central axis of the transparent body.
The light-emitting body may be provided so that its optical axis is inclined to the central axis of the light-transmitting body.

Further, in the above embodiment, an example was shown in which the entire circumference of the outer peripheral surface of the transparent body was brought into contact with the liquid mixture, but only one side surface may be brought into contact.

Further, in the above embodiment, an example was shown in which gasoline was used as the petroleum-based fuel, but other petroleum-based fuels such as light oil, kerosene, and residual oil may also be used.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a mixture ratio sensor, FIG. 2 is a sectional view of a light emitting diode, FIG. 3 is a sectional view of a conventional mixture ratio sensor, and FIG. 4 is a sectional view of a light emitting diode of a conventional mixture ratio sensor. FIG. 5 is a graph showing a change in the amount of light received by the measuring light receiving element when the light totally reflected within the light transmitting body is applied to a member supporting the light transmitting body. In the figure, 1...Mixing ratio sensor, 2...Case, 3
... Light emitting part, 4 ... Light transmitting body, 5 ... Light receiving part for measurement, 35 ... Light emitting diode, 35a ... Light emitting part, 35b, 35c ... Electrode, 35d ... Base, 35e ... Made of resin Coating, 36...
Temperature compensation photodiode, 55...Measurement photodiode.

Claims (1)

[Claims for Utility Model Registration] 1. A transparent body whose at least one side is brought into contact with a mixture of petroleum-based fuel and alcohol; a light-emitting element disposed on one end surface of the transparent body; and a measuring light receiving element disposed on the other end face for measuring the amount of light emitted from the light emitting element and passing through the light transmitting body; In the alcohol mixed fuel mixture ratio sensor that detects the mixture ratio of the mixed liquid based on the value measured by the measurement light receiving element by utilizing the change in the critical angle at the part that contacts with the light emitting element, the light emitting element is coated. A mixing ratio sensor for alcohol mixed fuel, characterized in that the size of the light emitting area of the light emitting element is controlled. 2. The alcohol mixed fuel mixture ratio sensor according to claim 1, wherein the light emitting element is a light emitting diode. 3. The alcohol mixed fuel mixture ratio sensor according to claim 2, wherein the coating is an electrode disposed on the transparent body side of the light emitting diode. 4. The alcohol mixed fuel according to claim 2 of the utility model registration, wherein the coating is a light-absorbing resin coated on the light-transmitting body side of the base that supports the light-emitting portion of the light-emitting diode. Mixing ratio sensor. 5. The alcohol mixed fuel mixture ratio sensor according to claim 1, wherein the petroleum-based fuel is gasoline. 6. The alcohol mixed fuel mixture ratio sensor according to any one of claims 1 to 5, wherein the light emitting body is arranged substantially on the central axis of the transparent body. .