JP3451013B2 - Optical liquid detector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical liquid detection device for detecting liquid properties such as liquid stain, transparency, and amount of fine particles.

[0002]

2. Description of the Related Art Conventionally, as an optical liquid detecting device for detecting liquid properties such as liquid stain, transparency, and amount of fine particles,
For example, there is known a device that optically detects deterioration of lubricating oil of an internal combustion engine (hereinafter, "internal combustion engine" is referred to as engine). As such an optical liquid detecting device, an optical liquid detecting device disclosed in Japanese Patent Laid-Open No. 61-164144 has been proposed.

[0003]

Problems to be Solved by the Invention JP-A-61-1641
The optical liquid detecting device disclosed in Japanese Patent No. 44 is provided with a slider for detecting the deterioration state of oil from the light transmittance, which is in contact with the oil boundary surface of the light emitting portion and the light receiving portion and slides in the oil passage direction. The interface between the light emitting portion and the light receiving portion is cleaned by sliding the slider.

However, in the above-mentioned conventional optical liquid detecting device, it is necessary to secure a space for mounting the slider, which causes a problem that the number of parts and the manufacturing cost increase. The present invention has been made to solve such a problem, and an object of the present invention is to provide an optical liquid detection device capable of accurately detecting a liquid property with a simple configuration.

Another object of the present invention is to provide an optical liquid detection device which does not require a special mounting space and can reduce the number of parts and the manufacturing cost.

[0006]

According to the optical liquid detecting device of the first aspect of the present invention, the optical detector has a light emitting portion and light emitted from the light emitting portion is incident on the light emitting portion. It has a light guide body that reflects on the contact surface that contacts, and a light receiving unit that receives the light reflected on the contact surface.The float floats on the liquid surface and can clean the contact surface. It is possible. Therefore, for example, by cleaning the contact surface with a float such as a liquid level detector that detects the height of the liquid surface, foreign matter such as powder floating in the liquid adheres to or accumulates on the contact surface and reflects light. It is possible to prevent the light from being disturbed or to change the amount of light received by the light receiving unit. Therefore, it is possible to stably and accurately detect the liquid property with a simple configuration without providing a special cleaning mechanism such as a wiper.

Further , according to the optical liquid detecting device of the first aspect of the present invention, the light guide is cylindrical and has the contact surface on the outer peripheral surface, and the float is arranged on the outer periphery of the contact surface. The contact surface can be reliably washed with the float. Therefore, the liquid state can be detected more stably and accurately with a simple structure. Claims 2 and 3 of the present invention
According to the optical liquid detection device described in paragraphs 5 and 5 , since the liquid level detector can detect the height of the liquid surface according to the position of the float, the liquid properties such as liquid stain, transparency, and amount of fine particles are detected. It is possible to perform both the function of detecting the liquid level and the function of detecting the height of the liquid surface with a relatively small physique.
Therefore, the physique can be reduced in size as an optical liquid detection device capable of detecting the liquid level, so that no special mounting space is required, the number of parts can be reduced, and the manufacturing cost can be reduced.

According to the optical liquid detecting device of the third aspect of the present invention, the liquid level detector is provided with the switch for opening and closing the electric circuit at the predetermined liquid level height inside the light guide. As compared with the optical liquid detection device having the above-mentioned switch on the outside, it is possible to further reduce the physical size and further reduce the mounting space. According to the optical liquid detection device of the fourth aspect of the present invention, since the optical detector has the temperature detector capable of detecting the temperature of the light guide and the liquid, the change of the refractive index due to the temperature change of the reflection part is prevented. It becomes possible to correct and improve the detection accuracy of the liquid property. Further, even if the liquid level detector is not provided with a special part such as a thermoswitch, it is possible to improve the liquid level detection accuracy by detecting the liquid level height only at a predetermined temperature or higher. Therefore, it is possible to improve the detection accuracy of the liquid property and the detection accuracy of the liquid level, and further reduce the size of the physique as compared with the optical liquid detection device having a thermoswitch or the like, and further reduce the mounting space. It is possible.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show an embodiment in which the present invention is applied to an oil deterioration detecting device that optically detects deterioration of engine lubricating oil. 1 and 3,
A shows the oil surface when the engine is stopped when the engine oil amount is sufficient. Further, in FIG. 5, B indicates the oil surface at the time of engine starting when the engine oil amount is sufficient.

As shown in FIG. 3, an oil deterioration detecting device 1 is provided.
0 is installed inside the oil pan 60 by the mounting portion 25 via the bracket 35, and optically detects insoluble particles that aggregate and grow as the oil 61 in the oil pan 60 deteriorates. Is a detection device for detecting deterioration of the oil 61. In addition, inside the oil pan 60, an oil strainer 7 is connected to an oil pump (not shown) and supplies oil 61 to an engine (not shown).
0 is set.

As shown in FIGS. 1 and 2, an oil deterioration detecting device 10 includes a light emitting diode (hereinafter, "light emitting diode" is referred to as an LED) 11 as a light emitting portion, and a photodiode (hereinafter, ""Photodiode" is referred to as PD) 12 and prism 2 as a light guide
0, a reed switch 30 serving as a switch, a float 31, and a determination unit 40, which are attached to the tip end portion 36 of the bracket 35.

The LED 11 is a light source containing light of red to infrared wavelengths. The PD 12 is a known photodiode such as a silicon photodiode, and can convert a received light signal into an electric signal. L
The ED 11 and the PD 12 are connected to the determination unit 40. As shown in FIG. 1, the prism 20 has a bottomed cylindrical shape made of transparent glass or transparent resin and has an opening 20a at one end and a bottom 20b at the other end. The opening 20a is located on the LED 11 and PD 12 side, and a reflective film 22 of metal or the like is vapor-deposited on the bottom 20b so that the optical path of light entering the prism 20 changes at the bottom 20b. Further, on the outer periphery of the bottom portion 20b,
A collar 26 having an outer diameter larger than an inner diameter of a hole of a float 31 described later is fixed, and the collar 26 prevents the float 31 from coming off. The outer peripheral surface 20c of the prism 20 has contact surfaces 21 and 23 that contact the oil 61.
And has an inner wall surface 3 forming the hole of the float 31
It is facing 2. When the oil surface of the prism 20 is not tilted, the light incident on the prism 20 receives the contact surface 21.
The light is totally reflected on the contact surface 23, and the light whose optical path is changed by the reflection film 22 on the bottom portion 20b can be totally reflected on the contact surface 23. In addition, the prism 20 has a space 24 for accommodating the reed switch 30.
Here, the LED 11, the PD 12, and the prism 20 constitute an optical detector.

The reed switch 30 is a reed switch that opens and closes an electric circuit of the oil level detection system that detects the height of the oil surface, and is a space 24 in the prism 20.
And is connected to the determination unit 40. The reed switch 30 is operated by the magnetic force of an annular magnet 33, which will be described later, incorporated in the float 31. The float 31 has a plate shape having a hole portion, has a hardness lower than that of the prism 20, has a specific gravity smaller than that of the oil 61, and has durability against the oil 61. Consists of. Float 31
As shown in FIG. 1, it is possible to contact the tip end portion 36 of the bracket 35 when the engine is stopped when the engine oil amount is sufficient. The surface drop causes the oil to float on the oil surface, as shown in FIG. The inner wall surface 32 forming the hole of the float 31 faces the outer peripheral surface 20c of the prism 20. Further, a pair of magnets 33 and 34 is incorporated inside the float 31, and the magnetic force of the magnet 33 can operate the reed switch 30. Here, the float 31 constitutes an oil level detector as a liquid level detector together with the reed switch 30, and it is possible to detect the height of the oil surface according to the position of the float 31. Further, in the float 31, the inner wall surface 32 slides on the outer peripheral surface 20c of the prism 20 due to the change of the oil surface, and the contact surfaces 21 and 23 are formed.
It is configured to be able to wash.

The determination unit 40 is formed on a printed wiring board 400 provided at the upper end of the oil deterioration detection device 10, and as shown in FIG. 4, a thermistor thermometer 52 as a temperature detector and a calculation unit ( Hereinafter, the "arithmetic unit"
41 and a delay circuit (hereinafter, "delay circuit" is a DC
42). As shown in FIG. 4, the determination unit 40 receives power supply from an external DC power supply 51 and supplies power to the LED 11 and the PD 12.

The thermistor thermometer 52 is connected to the ALU 41 and the reed switch 30. The thermistor thermometer 52 includes the prism 20 and the oil 61 shown in FIG.
The temperature T is detected. Therefore, the change in the refractive index due to the temperature change of the prism 20 is corrected to improve the oil deterioration detection accuracy, and
Even if the oil level detector is not provided with a special part such as a thermoswitch, it is possible to improve the oil level detection accuracy by detecting the height of the oil surface only at a predetermined temperature or higher.

The output signal of the judgment result of the judging section 40 is used as an electronic control unit for the engine (hereinafter, "electronic control unit" is referred to as ECU).
The ECU 50 is connected to the oil state indicator 53 in the driver's seat. A signal line 501 that receives a command from the ECU 50 that operates the oil deterioration detection device 10 is provided between the determination unit 40 and the ECU 50.

The DC 42 is a delay circuit for delaying the switching of the ON / OFF signal from the reed switch 30 for a predetermined time, and the warning light 4 for the oil level lowering in the driver's seat.
It is connected with 3. Even if the engine oil amount is sufficient, even if the reed switch 30 is mistakenly turned on due to the inclination of the oil surface due to vehicle acceleration / deceleration, turning, etc. It is possible to give a delay of the delay time before the warning light 43 starts to light.

Next, the oil deterioration detecting device 1 having the above structure
The operation of 0 will be described. (1) As shown in FIG. 1, when the engine is stopped when the engine oil amount is sufficient, the oil surface of the oil 61 is in the position A. At this time, the float 31 in the oil 61 tries to float and the tip portion 3 of the bracket 35
It is in contact with 6 and is located above the prism 20. As a result, the reed switch 30 is in the off state and is in a state in which it cannot be energized.

(2) When the engine is started, the oil is circulated in the engine by the operation of the oil pump, and the oil level is lowered from the position A shown in FIG. 1 to the position B shown in FIG.
Along with this, the float 31 floats on the oil surface and moves to the substantially central portion of the prism 20, as shown in FIG. As a result, as shown in FIGS. 6A and 6B, the inner wall surface 32 of the float 31 slides on the outer peripheral surface 20c of the prism 20 in the arrow Z direction, and the inner wall surface 32 causes the contact surface of the prism 20 to contact. Wash 21 and 23. In this way, the contact surfaces 21 and 23 of the prism 20 are cleaned and the contact surface 2
Dirt adhering to 1 and 23 is removed. That is,
Since the dirt attached to the contact surfaces 21 and 23 of the prism 20 is often caused by the intermolecular suction force, it is effective to remove the dirt by applying a physical external force by the float 31 to the dirt. Is. It also has the effect of preventing dirt from accumulating and growing on the contact surfaces 21 and 23.

(3) As shown in FIG. 5, when the contact surfaces 21 and 23 are cleaned, the incident light 13 emitted from the LED 11 to the prism 20 is totally reflected by the contact surface 21, and this total reflection is performed. The optical path of the reflected light 14 is changed by the reflection film 22 at the bottom portion 20b, the reflected light 15 having the changed optical path is totally reflected again on the contact surface 23, and the totally reflected reflected light 16 is incident on the PD 12. At the time of total internal reflection on the contact surfaces 21 and 23, the reflected light changes depending on the amount of particles in the oil, particularly so-called soot. Therefore, the deterioration of the oil can be determined extremely clearly by the change in the intensity of the reflected light 16 received by the PD 12. Further, as shown in FIG. 4, the thermistor thermometer 52
Since it is possible to detect the temperature T of the prism 20, it is possible to correct the change in the refractive index due to the temperature change of the prism 20 and improve the accuracy of oil deterioration detection. Then, the detection result of the oil deterioration is displayed on the oil state indicator 53.

(4) Even if the engine oil amount is sufficient, even if the reed switch 30 is erroneously turned on due to the inclination of the oil surface due to acceleration / deceleration of the vehicle, turning, etc., it is shown in FIG. A delay of a delay time is given by the DC 42 from when the reed switch 30 is turned on to when the warning lamp 43 starts to light. Therefore, it is possible to prevent erroneous detection of insufficient oil due to the inclination of the oil surface.

When the amount of engine oil decreases and the oil level falls below a predetermined reference level, the float 12 floating on the oil level is positioned below the prism 20 as the oil level decreases. As a result, the reed switch 30 is turned on by the magnetic force of the magnet 33, and the state becomes energizable. When the reed switch 30 is turned on for a certain period of time or longer, an electric signal for instructing the decrease of the oil level, that is, a current flows through the warning lamp 43 and the warning lamp 43 is turned on. Then, the driver is warned that the oil is insufficient.

In the embodiment described above, the contact surfaces 21 and 23 of the prism 20 are not provided with a special cleaning mechanism such as a wiper, and the contact surface is formed by the inner wall surface 32 of the float 31 constituting the oil level detector. With a relatively simple configuration of cleaning 21 and 23,
Contamination of the contact surfaces 21 and 23 can be prevented or removed. Therefore, the deterioration of the oil can be stably and accurately detected with a simple configuration.

Further, in this embodiment, both the function of detecting the deterioration of oil and the function of detecting the oil level can be achieved with a relatively small physique.
Therefore, the physical constitution of the oil deterioration detecting device 10 capable of detecting the oil level can be reduced,
No special mounting space is required, the number of parts can be reduced, and the manufacturing cost can be reduced.

Furthermore, in this embodiment, since the reed switch 30 which constitutes the oil level detector is housed inside the prism 20, the physical constitution is larger than that of the oil deterioration detecting device having the reed switch 30 outside. The size can be further reduced, and the mounting space can be further reduced. Furthermore, in the present embodiment, the determination unit 40 can detect the temperatures of the prism 20 and the oil 61, so that the change in the refractive index due to the temperature change of the prism 20 is corrected to improve the accuracy of oil deterioration detection. The oil level detector is not provided with a special part such as a thermoswitch, and the height of the oil surface is detected only at a predetermined temperature or higher to improve the oil level detection accuracy. Therefore, the accuracy of oil deterioration and the accuracy of oil level detection can be improved, and the size can be further reduced compared to an oil deterioration detection device having a thermoswitch, etc., and the mounting space can be further reduced. Is.

In the present embodiment, the prism 20 has a cylindrical shape, but in the present invention, the prism may have a prismatic shape. Further, in this embodiment, the float 31 constituting the oil level detector is the contact surface 21 of the prism 20.
However, in the present invention, any float that floats on the oil surface and can clean the contact surface of the prism may be provided.

Further, in the present embodiment, the present invention is applied to the oil deterioration detecting device 10 for optically detecting the deterioration of the engine lubricating oil, but the present invention is not limited to the deterioration of the oil, and the liquid stains. The present invention can be applied to a liquid detection device that optically detects liquid properties such as transparency and the amount of fine particles.

[Brief description of drawings]

FIG. 1 shows an embodiment in which the present invention is applied to an oil deterioration detecting device, and is an enlarged view of a main part of FIG.

FIG. 2 is a schematic view showing an embodiment in which the present invention is applied to an oil deterioration detecting device.

FIG. 3 shows an embodiment in which the present invention is applied to an oil deterioration detecting device, and is a schematic configuration diagram showing the time when the engine is stopped when the engine oil amount is sufficient.

FIG. 4 is an explanatory diagram of a signal system of the oil deterioration detection device according to the embodiment of the present invention.

FIG. 5 is a schematic view showing an embodiment in which the present invention is applied to an oil deterioration detecting device, and showing the engine starting when the engine oil amount is sufficient.

FIG. 6 is a schematic view for explaining the operation of the oil deterioration detecting device according to the embodiment of the present invention, and showing a state in which the float is in contact with the prism.

[Explanation of symbols]

10 Oil deterioration detector (optical liquid detector) 11 LED (light emitting part) 12 PD (light receiving part) 20 Prism (light guide) 21, 23 Contact surface 30 reed switch (switch) 31 float 32 inner wall surface 33 magnets 40 Judgment section 52 Thermistor thermometer (temperature detector) 61 oil

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Minoru Tomita 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Corporation (56) References JP-A-9-33426 (JP, A) JP-A-9-138196 (JP, A) Actual development Sho 58-56106 (JP, U) Actual development Sho 63-128448 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01N 21/00-21 / 61 PATOLIS

Claims (5)

(57) [Claims] 1. A light-emitting part, which is cylindrical and has an outer peripheral surface in contact with a liquid.
It has a contact surface to touch, and the light emitted from the light emitting part
An optical detector having a light guide that reflects the light emitted from the contact surface and a light receiving portion that receives the light reflected by the contact surface; and an optical detector that is arranged on the outer periphery of the contact surface and floats on the liquid surface. And a float capable of cleaning the contact surface, the optical liquid detecting device. 2. An optical liquid detection apparatus according to claim 1, characterized in that it comprises a detectable liquid level detector height of the liquid surface in accordance with the position of the float. 3. The liquid level detector includes a switch that opens and closes an electric circuit at a predetermined liquid level height, and the switch includes:
It is provided inside the light guide.
2. The optical liquid detection device described in 2 . Wherein said optical detector is an optical liquid detector of any one of claims 1 to 3, characterized in that it comprises a detectable temperature detector the temperature of the light guide and liquid apparatus. 5. The light emitting section and the light emitted from the light emitting section
Light guide that makes incident light and reflects this light on the contact surface that contacts the liquid
Light receiving part for receiving light reflected by the body and the contact surface
An optical detector having a float, a float that floats on the liquid surface and can clean the contact surface, and a liquid that can detect the height of the liquid surface according to the position of the float.
Position detector, and an optical liquid detector characterized by comprising:
apparatus.