JPH04262241A - Liquid mixing-ratio sensor - Google Patents

Abstract

PURPOSE:To improve the accuracy of the detected mixing ratio by accurately detecting the temperature of mixed liquid with good response. CONSTITUTION:A fuel well 2 for passing liquid to be measured is formed. A fuel path 1 wherein a temperature sensor is arranged and optical glass 20 whose edge 21 is exposed through an opening 13 of a main-body metal fitting 11 are provided in the fuel well 2. A light emitting diode 31 which emits light toward the edge 21 and a photodiode 34 which receives the reflected emitted light from the edge are arranged in the main-body metal fitting 11 in a sensor unit 10. The edge 21 is arranged so that the edge 21 is exposed in the fuel well 2.

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 needs to be corrected based on the temperature of the mixed liquid.

0003

[Problems to be Solved by the Invention] However, for example, when a mixed fuel in the form of a mixed liquid whose mixture ratio is detected is supplied to an engine, and the engine is controlled based on the detected mixture ratio, As the mixed fuel is sent to the engine one after another,
Temperature detection of the mixed liquid must be performed quickly to correct the detected refractive index. SUMMARY OF THE INVENTION An object of the present invention is to use a liquid mixture ratio sensor to accurately detect the temperature of a mixed liquid whose mixture ratio is to be detected, with good responsiveness, and to improve the accuracy of the detected mixture ratio.

0004

[Means for Solving the Problems] The present invention forms a liquid passage through which a liquid to be measured in which two types of translucent liquids are mixed is passed, and a temperature sensing element is disposed within the liquid passage. A passage portion and an optical prism whose end face is exposed from the opening of the container are provided in the container, and a light emitting element that emits irradiated light toward the end face and a light receiving element that receives at least the irradiated light reflected by the end face are provided in the container. and a refractive index detection section disposed within the container, the end surface being exposed to the liquid passage.

[0005]

[Operation] In the present invention, the end face of the optical prism for detecting the refractive index of the mixed liquid is exposed to the liquid passage,
Further, a temperature sensing element is disposed within the liquid passage. Therefore, the refractive index of the mixed liquid passing through the liquid passage is detected quickly, and the temperature detection element exchanges heat with the mixed liquid passing through the liquid passage, so the sensitivity to the temperature of the mixed liquid is improved and The temperature of the liquid can be detected quickly. As a result, when the mixed liquid whose refractive index is detected passes through the liquid passage, the temperature of the mixed liquid can be detected almost simultaneously.

[0006]

According to the present invention, since the mixed liquid as the liquid to be measured passes through the liquid passage, the mixed state of the mixed liquid is stabilized, and the refractive index can be detected stably. Also,
The temperature sensing element can sensitively detect the temperature of the mixed liquid passing through it, so it has excellent responsiveness to temperature changes.
The accuracy of the mixture ratio calculated by a calculation device or the like is improved. As a result, the device can be easily controlled using the detected mixture ratio.

[0007]

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

In the fuel mixture ratio sensor 100 shown in FIG. 1, 10 is a sensor unit as a refractive index detection section of the present invention, and 1 is a liquid passage through which the mixed fuel whose mixture ratio is detected by the sensor unit 10 is passed. This is a stainless steel fuel path as a passage portion of the present invention to be formed. 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. The fuel path 1 is equipped with a temperature sensor 5 that protrudes toward the center of the fuel reservoir 2, as shown in FIG. The temperature sensor 5 has a temperature sensing element inserted and fixed into a metal pipe with a closed end disposed in the fuel reservoir 2. The temperature sensor 5 is brazed into a hole formed in the fuel path 1, and is attached to a metal pipe with a closed end. Airtightness within the reservoir 2 is ensured. As a temperature-sensitive element, it is preferable to use a thermistor or a resistor whose resistance value changes linearly with respect to temperature changes.
It does not necessarily have to be linear. A fuel path 1 equipped with a temperature sensor 5 and fuel connecting pipes 101 and 102 is integrated in advance with a sensor body 103 made of resin, and the upper part thereof is a fitting opening for fitting the sensor unit 10. 1 , a sensor unit 10 is fitted facing the fuel reservoir 2 , and the sensor unit 10 is kept airtight by an O-ring 6 . Note that a control board 104 is provided within the sensor body 103 and includes a hybrid IC having an operational amplifier and the like that constitute a control circuit.

As shown in FIG. 3, the sensor unit 10 includes an optical glass 20 fixed to a main metal fitting 11 made of stainless steel, a light emitting element substrate 32 equipped with a light emitting diode 31 as a light emitting element, and two light receiving elements. A light-receiving element substrate 3 equipped with photodiodes 33 and 34
5 are supported in a predetermined arrangement relative to the optical glass 20 within the metal shell 11 by element holders 36 and 37 made of resin.

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. A sensor unit 1 is installed on the outside of the metal shell 11.
A flange 14 that serves as a locking wall when 0 is fitted into the fuel path 1 is integrally formed.

The optical glass 20 has a cylindrical shape, and is bonded to the bottom part 12 of the metal shell 11 with an annular glass 15 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
The element holder 37 is covered with the lead wires 38 and 39 protruding from the element holder 37 in which a plurality of through holes 40 corresponding to the number 9 are formed. The element holder 36 and the element holder 37 are sealed by the adhesive 16 and are integrated with the epoxy resin 17 to ensure airtightness on the inside.

The integrated element holders 36 and 37 are inserted into the inside of the metal shell 11 until the flange 36a is locked, and the thin part 18 of the metal shell 11 is caulked inward to connect the two metal pieces. It is fixed via rings 22, 23 and an O-ring 24. Further, the O-ring 9 ensures airtightness with the metal shell 11.

As shown in FIG. 1, the sensor unit 10 having the above configuration is fixed to the fuel path 1 integrated with the sensor body 103 made of resin, and each lead wire 3
8 and 39 are connected to the control board 104, and the temperature sensor 5 is connected to the control board 104 via a connection line (not shown).

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. The control board 104 converts the light reception signal of the photodiode 34 and the temperature sensor 5 into a predetermined transmission signal, and transmits the signal to a microcomputer (not shown) separately mounted on the vehicle. The microcomputer determines the refractive index based on these signals, and further corrects the refractive index to determine the mixture ratio of the mixed fuel.

As described above, in the fuel mixture ratio sensor 100 of this embodiment, the sensor unit 10 for detecting the refractive index is provided facing the fuel reservoir 2 of the fuel path 1.
In addition, since a temperature sensor 5 for detecting the temperature of the mixed fuel is arranged in the fuel reservoir 2, the refractive index of the mixed fuel can be stably detected, and the temperature of the mixed fuel can be detected with high sensitivity. , the responsiveness of mixing ratio detection is excellent. Therefore, the detection accuracy of the mixture ratio is improved, and it is easy to control the engine based on the detected mixture ratio.

[Brief explanation of the drawing]

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

FIG. 2 is a plan view showing a fuel path, a fuel connection pipe, and a sensor body in a fuel mixture ratio sensor showing an embodiment of the present invention.

FIG. 3 is a sectional view of main parts for explaining a sensor unit of a fuel mixture ratio sensor showing an embodiment of the present invention.

[Explanation of symbols]

1 Fuel path (path section) 2 Fuel reservoir (liquid path) 5 Temperature sensor 10 Sensor unit (refractive index detection section) 11 Metal shell (container) 13 Opening (opening) 20 Optical glass (optical prism) 21 End surface 31 Light emitting diode (Light emitting element)

Claims (1)

[Claims] Claim 1: A passage portion that forms a liquid passage for passing a liquid to be measured in which two types of translucent liquids are mixed, and in which a temperature sensing element is disposed, and an end face of a container. An optical prism exposed from an opening is provided in the container, and a light emitting element that emits irradiation light toward the end surface and a light receiving element that receives at least the irradiation light reflected on the end surface are arranged in the container. an optical liquid mixture ratio sensor, the sensor having a detecting section, the end surface being exposed to the liquid passage.