JPH04256835A - Liquid mixing-ratio sensor - Google Patents

Abstract

PURPOSE:To make it possible to detect the temperature of mixed liquid readily by fixing a temperature detecting element to the inside of a metal container in the vicinity of an opening part. CONSTITUTION:A resistor 15 as a temperature detecting element for detecting the temperature of mixed fuel passing the inside of a fuel well 2 is fixed to the inside of an element chamber 14 in the vicinity of an opening part 13 of a metal container 11. The refractive index of the mixed fuel passing the fuel well 2 is unequivocally determined in response to the mixing ratio and the temperature of the mixed fuel. The critical angle of the reflecting angle of the emitted light from a light emitting diode 31 is determined in response to the refractive index. Therefore, the amount of the emitted light which is reflected from an edge 21 of optical glass 20 is determined in response to the mixing ratio of the mixed fuel. The amount of the light in response to the mixing ratio is received with a photodiode 34. The refractive index is obtained from the received signal of the photodiode 34. The refractive index is further corrected with the temperature detected with the resistor 15. Thus, the mixing ratio of the mixed fuel can be obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical liquid mixture ratio sensor for measuring the mixture ratio of liquids in a mixed fuel or the like in which two types of fuel are mixed.

0002

[Prior Art] For example, in order to measure the mixing ratio of a liquid such as a mixed fuel mixture of gasoline and alcohol, the end surface of an optical glass provided in a metal container is exposed from the metal container and the mixed liquid is measured. The mixing ratio of the liquid can be adjusted by taking advantage of the fact that when the end face is irradiated with light from inside the metal container, the reflectance of the irradiated light at the interface differs depending on the refractive index of the mixed liquid. A liquid mixing ratio sensor for detecting the liquid mixture ratio has been considered. In this case, the refractive index of the mixed liquid is
Since it changes depending on the temperature, the detected refractive index is
It is necessary to make corrections based on the temperature of the mixed liquid, and for example, it is conceivable to arrange a temperature sensing element in the flow path of the liquid to be measured.

0003

[Problems to be Solved by the Invention] However, in order to arrange the temperature sensing element in the flow path of the mixed liquid, airtightness for the flow path is required, which increases the number of parts,
There are problems in that the structure of the sensor becomes complicated and the number of manufacturing steps increases. SUMMARY OF THE INVENTION An object of the present invention is to provide, in a liquid mixture ratio sensor, means for correcting the refractive index of a mixed liquid that changes depending on temperature, with a simple configuration.

0004

[Means for Solving the Problems] The present invention provides an optical glass that is arranged in an opening of a metal container, an end surface of the optical glass is exposed to the opening, and the metal container and the optical glass are bonded together by a welding glass. At the same time, a light emitting element that emits irradiation light from inside the optical glass toward the end surface and a light receiving element that receives at least the irradiation light reflected by the end surface are provided in the metal container, and the end surface has two types. In an optical liquid mixture ratio sensor that is immersed in a liquid to be measured in which a translucent liquid is mixed, the technical means is that a temperature sensing element is fixed to the inside of the metal container near the opening.

[0005]

[Operation] In the present invention, a temperature sensing element is fixed to the inside of the metal container in the vicinity of the opening for placing the optical glass. When measuring the mixing ratio of the mixed liquid, when the end surface of the optical glass is immersed in the mixed liquid, the metal container with the optical glass bonded to the opening is also immersed in the mixed liquid at the same time. Therefore, the temperature of the metal container approaches the temperature of the mixed liquid,
A temperature sensing element fixed to the inside of the metal container can detect the temperature of the mixed liquid through the metal container.

[0006]

According to the present invention, the temperature of the mixed liquid can be detected by fixing the temperature sensing element inside the metal container for temperature-correcting the refractive index of the mixed liquid to be detected. Further, since there is no need to separately ensure airtightness due to the provision of the temperature sensing element, there is no need to complicate the structure of the sensor. Therefore, the temperature of the mixed liquid can be detected with a simple configuration.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained based on an embodiment of a fuel mixture ratio sensor 100 for detecting a fuel mixture ratio in a mixed fuel mixture of gasoline and alcohol.

In the fuel mixture ratio sensor 100 shown in FIG. 1, 10 is a sensor unit as a liquid mixture ratio sensor of the present invention, and 1 is a stainless steel plate for passing the mixed fuel whose mixture ratio is detected by the sensor unit 10. This is a manufactured fuel path. The fuel path 1 is disposed in a fuel supply path for supplying fuel to the internal combustion engine from a fuel tank (not shown), and has a fuel reservoir 2 that serves as a cylindrical measurement chamber for detecting the fuel mixture ratio. , connection ports 3 and 4 are formed in the fuel reservoir 2 to face each other and to which fuel connection pipes 101 and 102 communicating with the fuel reservoir 2 are connected. In the fuel path 1, the upper part of the fuel reservoir 2 is a fitting opening for fitting the sensor unit 10.
is fitted facing the fuel reservoir 2 with airtightness ensured by an O-ring 5.

The sensor unit 10 includes an optical glass 20 fixed to a main metal fitting 11 made of stainless steel, an element substrate 32 for light emission equipped with a light emitting diode 31 as a light emitting element, and a photodiode 33 as two light receiving elements.
, 34 is supported in a predetermined position relative to the optical glass 20 within the metal shell 11 by resin element holders 36 and 37.

The main metal fitting 11 has a bottomed cylindrical shape exhibiting a two-stage structure having different diameter lengths, and an opening 13 facing the fuel reservoir 2 and having an optical glass 20 bonded thereto is formed in the bottom portion 12. Further, an element chamber 14 projecting outward is provided. A resistor 15 as a temperature detection element for detecting the temperature of the mixed fuel passing through the fuel reservoir 2 is fixed inside the element chamber 14 with an adhesive.
5 is connected to a lead wire 15a for connection. A flange 16 that serves as a locking wall when the sensor unit 10 is fitted into the fuel path 1 is integrally formed on the outside of the metal shell 11 .

The optical glass 20 has a cylindrical shape, and is bonded to the bottom part 12 of the metal shell 11 by an annular glass 17 for fusion by heat treatment in a nitrogen atmosphere using a predetermined jig, and the opening 13 is sealed. The airtightness of the joint between the metal fitting 11 and the optical glass 20 is ensured.

Each of the element substrates 32 and 35 is made by bonding each element onto an alumina substrate, and each surface is provided with a conductor pattern for bonding the light emitting diode 31 or the photodiode 33, 34. There is. Here, the light emitting diode 31 is mounted on the element substrate 32 in the form of a chip, and the photodiode 33 is made of a planar chip.
, 34 are surface-mounted on the element substrate 35. Further, each element substrate 32, 35 is provided with a plurality of lead wires 38, 39 connected to each element via a conductive pattern.

The photodiode 33 directly receives the light emitted from the light emitting diode 31 and transmits a light reception signal to the control circuit in order to maintain the brightness of the light emitting diode 31 constant. On the other hand, the photodiode 34 selects a portion of the light emitted from the light emitting diode 31 from the fuel reservoir 2.
The light reflected by the end surface 21 of the optical glass 20 forming an interface with the light emitting diode 31 is received together with the light directly received from the light emitting diode 31, and a light reception signal corresponding to the amount of light received is transmitted to the control circuit.

Each element substrate 32, 35 has a flange 36a.
After being inserted and supported in a supporting slit (not shown) of a substantially cylindrical element holder 36 equipped with
An element holder 37 in which a plurality of through holes 40 corresponding to No. 9 and a through hole 41 for passing the lead wire 15a through are formed.
The lead wires 38 and 39 are made to protrude from the lead wire 1.
The through holes 40, 41 are sealed with silicone adhesive 18 with the lead wires 38, 39, 15a passing through them, and the element holders 36 and 37 are covered with epoxy adhesive. The resin 42 ensures internal airtightness and is integrated.

The element holders 36 and 37, which are integrated and have respective element substrates 32 and 35, are inserted inside the metal shell 11 until the flange 36a is locked, and the thin part of the metal shell 11 is caulked inward. 19 through two metal rings 6, 7 and an O-ring 8. Further, the O-ring 9 ensures airtightness with the metal shell 11.

The sensor unit 10 having the above configuration has a sensor body made of resin (not shown) that connects the fuel path 1.
, sensor unit 10 and fuel connection pipes 101, 102
is integrated, and each lead wire 38, 39 is connected to a hybrid I having an operational amplifier etc. provided in the sensor body.
A control board (not shown) equipped with C is connected. Further, the resistor 15 is also connected to the control board by a lead wire 15a.

The refractive index of the mixed fuel passing through the fuel reservoir 2 is uniquely determined depending on the mixture ratio of the mixed fuel and its temperature, and the critical angle of reflection of the light irradiated by the light emitting diode 31 is determined depending on the refractive index. Since the angle is determined, the amount of irradiated light reflected by the end surface 21 of the optical glass 20 is determined according to the mixture ratio of the mixed fuel, and the amount of light corresponding to the mixture ratio is reflected by the photodiode 3.
The light is received at 4. On the control board, the photodiode 34
The refractive index is determined from the light reception signal of the resistor 15.
The mixture ratio of the mixed fuel can be determined by correcting the refractive index based on the temperature detected by.

As described above, in the fuel mixture ratio sensor 100 of this embodiment, the resistor 15 for temperature detection is fixed to the bottom 12 of the metal shell 11 to which the optical glass 20 is bonded. Temperature can be easily detected. In this embodiment, the element chamber 1 protrudes from the bottom 12.
4 and the resistor 15 is arranged therein, however, the resistor 15 may be directly fixed to the flat bottom part 12. In this embodiment, in order to make the fuel mixture ratio sensor 100 smaller, the optical glass 20 is eccentrically placed inside the metal shell 11, but the optical glass 20 may also be arranged concentrically with the metal shell 11 and others. . In the above embodiment, a resistor is used as the temperature detection element, but other temperature detection elements such as a thermistor or a diode may be used.

[0019]

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a fuel mixture ratio sensor showing an embodiment of the present invention.

[Explanation of symbols]

10 Sensor unit (liquid mixture ratio sensor) 11
Metal shell (metallic container) 13 Opening (opening) 15 Resistor (temperature sensing element) 17 Annular glass (glass for fusion) 20 Optical glass 21 End surface 31 Light emitting diode (light emitting element)

Claims (1)

[Claims] 1. An optical glass is disposed in an opening of a metal container, an end surface of the optical glass is exposed to the opening, and the metal container and the optical glass are bonded by a welding glass. A light emitting element that emits irradiation light from inside the optical glass and a light receiving element that receives at least the irradiation light reflected from the end face are provided in the metal container, and the end face is a mixture of two types of translucent liquids. 1. An optical liquid mixture ratio sensor immersed in a liquid to be measured, characterized in that a temperature sensing element is fixed to the inside of the metal container near the opening.