JPH01119741A - Detecting apparatus of turbidity of oil - Google Patents

Abstract

PURPOSE:To enable the detection of turbidity of a lubricating oil, by introducing the lubricating oil between a light-emitting element and a photosensing element and by varying a distance between these elements. CONSTITUTION:A light from a light-emitting element 1 reaches a photosensing surface 2 through an inner-oil optical path varying to be of distances Da and Db. On the occasion, the intensities Ia and Ib of the light reaching the photosensing surface 2 are expressed by Ia=Io.C.B.e<->K<alpha>D<a>... (I) and Ib= Io.C.B.e<->K<alpha>D<b>... (II) respectively (where Io is an emission intensity of a light- emitting element (in the case when an oil is new with turbidity alpha=0, when no film due to contamination or the like sticks on glass surfaces 3' and 4' and before the emission intensity characteristic of the light-emitting element 1 varies), C is a light absorption coefficient of the film due to the contamination on the glass surfaces, B is a variation coefficient of the emission intensity of the light-emitting element itself, and alpha is the turbidity of the oil (concentration of carbon in the oil). When the percentage of the turbidity of the oil is determined from the equations (I) and (II), therefore, C and B are eliminated and the turbidity alpha can be determined by an equation III.

Description

[Detailed description of the invention] [Summary] Lubricating oil is introduced between the light emitting part and the light receiving part, and two types of gaps are realized by changing the distance between the light emitting part and the light receiving part. Calculate the degree of pollution.

[Industrial application field]

The present invention relates to a lubricating oil contamination level detection and measurement device.

The device according to the present invention is used, for example, as an on-vehicle measuring device to measure the concentration of carbon particles contained in lubricating oil of an internal combustion engine, particularly a diesel engine.

[Conventional technology]

In internal combustion engines, especially diesel engines, a large amount of carbon particles contained in exhaust gas are mixed into the lubricating oil, so the lubricating oil becomes contaminated in a relatively short time compared to a gasoline engine. These carbon particles increase wear on the sliding parts of various parts of the engine, so the lubricating oil change intervals for diesel engines are generally shorter than for gasoline engines, which are hardly contaminated by carbon particles. On the other hand, the degree of contamination of lubricating oil due to carbon particles varies greatly depending on the operating conditions of the engine. Under driving conditions that involve a lot of sudden acceleration and sudden starts, such as when driving on a highway, in the mountains, or in a taxi, pollution tends to progress more quickly than when driving in general. However, the lubricating oil change interval has generally been determined solely by the distance traveled by the vehicle, regardless of these operating conditions.

For this reason, in some vehicles, oil may be changed even though the pollution has not progressed, or conversely, oil may not be changed even though the time for oil change has passed, resulting in lubricating oil being replaced. In some cases, oil was wasted or oil changes were delayed, resulting in a significant increase in wear on the sliding parts.

Therefore, optical methods have been used to measure the degree of contamination of carbon particles in oil, which has a somewhat linear correlation with mileage and also with other properties of lubricating oil, such as total base number or p-old linearity. There is a known method of detecting the lubricating oil and thereby notifying the lubricant when it is time to change it. This type of device is disclosed, for example, in Japanese Unexamined Patent Publication No. 57-98842 or Japanese Utility Model Application No. 57-182152. These devices detect the degree of contamination of the lubricating oil based on the degree of transparency of the lubricating oil interposed between the light-emitting element immersed in oil and the light-receiving element, and based on this signal, the indicator lamps etc. on the display circuit are turned on. The purpose is to notify the driver of the degree of contamination of the lubricating oil and to realize the appropriate replacement timing.

[Problem that the invention seeks to solve]

As conventional means for measuring the degree of contamination of lubricating oil, the above-mentioned Japanese Unexamined Patent Publication No. 57-98842 and Utility Model Application No. 57-1821 are used.
In addition to Japanese Utility Model Application No. 52, there are publications such as Japanese Utility Model Application No. 60-59142 and Japanese Utility Model Application Publication No. 60-131615.

These documents disclose means for interposing lubricating oil between the light emitting and light receiving elements and measuring lη turbidity based on the magnitude of light absorption by the lubricating oil. The configuration and operation of the prior art will be explained using these as examples. The one shown in Fig. 12 is a typical device. 111 is a light source such as a light emitting diode, 112 is a light receiving element made of a photodiode or a phototransistor, and 121 and 122 are windows made of glass or transparent synthetic resin. be.

The distance between the opposing surfaces 121 and 122 (distance D) is the optical path gap 113. Reference numeral 115 is a part of the body made of resin or part of metal, which not only holds the light source and the light receiving element in a specified position, but also serves to attach it to the engine's oil retainer and other parts. Reference numeral 116 indicates a terminal section for electrically communicating the light source and the light receiving element with a signal processing and display section (not shown).

However, when this type of device is mounted on a vehicle and operated continuously for a long period of time, the glass surface of the windows 121 and 122 of the light emitting element 111 or the light receiving element 112 may be exposed to the surface of the surface in the oil. A film consisting of
The film absorbs the light emitted from the light emitting element, and the emission intensity characteristics of the light emitting element itself change due to thermal effects, making it difficult to accurately measure the degree of contamination. In addition, in light-emitting diodes, which are commonly used as light-emitting devices, the temperature dependence of the light-emitting intensity is as shown in FIG. This is also a cause of measurement error.

[Means for solving problems]

As a means for solving the above-mentioned problem, a detection section is provided that has a light emitting section and a light receiving section that receives light from the light emitting section, and a gap is provided between the light emitting section and the light receiving section to prevent internal combustion. When the detection part is immersed in lubricating oil of the engine, the lubricating oil is introduced into the gap, and the light emitting part and/or the light receiving part are displaced. A method for detecting contamination of the lubricating oil by providing means for changing the thickness of the lubricating oil to be measured between the lubricating oils and calculating the outputs of the light receiving section at at least two different thicknesses. A pollution level detection device is provided.

[For production] The basic principle diagram according to the present invention is shown in FIGS. 1 and 2.

This device measures the intensity of light that has passed through two different oil film thicknesses Da and Db (optical path length of light in oil) and calculates the degree of contamination. The biggest feature is that in order to realize different oil film thicknesses Da and Db formed in the gap between the light-receiving elements 2, the positions of the light-emitting element and the light-receiving element, or either one of them, are displaced using some kind of drive source. .

According to this invention, there is an advantage that it is completely unaffected by the influence of light absorption by a film caused by dirt or the like adhering to the glass surfaces of the light emitting element and the light receiving element, and by changes in the emission intensity characteristics of the light emitting element. In the figure, ■ is a light emitting element, 2
is a light receiving element consisting of a photodiode or the like. First, the light emitted from the light emitting element 1 reaches the light receiving surface 2 through optical paths in the oil having distances QDa and Db, respectively. In order to realize the optical path lengths Da and Db, this figure shows the case where the light emitting element is displaced by (Da - Db) in either the front or back direction, but of course the light receiving element can also be displaced or both. Even if they are both displaced, there is no problem with some of them.

At this time, the intensity of the light reaching the light receiving surface is Ia and Ib, respectively.
Then, Ia and rb are each expressed by the following formula % Ia -fo -C-B -e-'α"
(1) Tb = Io −C−B −e−”α
Db (2) However, Io Two light-emitting element emission intensity (new oil (when the degree of contamination α = 0>, and 3' on the glass surface)
And 4' does not have a film due to dirt, etc., and the light emitting element 1
(emission intensity before the emission intensity characteristics change).

C: Light absorption coefficient due to film such as dirt on glass surface, B:
: Change coefficient of emission intensity of the light emitting element itself, K: Constant, α;
Oil pollution level (carbon concentration in oil).

Therefore, from equations (1) and (2), the oil pollution degree α (%)
When , C and B are deleted and the degree of pollution α is determined by the following formula.

Therefore, as is clear from equation (3), according to the present invention, it is possible to measure the lη turbidity of oil without being affected by dirt on the glass surface or changes in the light intensity characteristics of the light emitting element. . Therefore, there is no influence on the temperature dependence of the light intensity characteristics of the light emitting element as in the conventional case. Furthermore, the zero point drift of the logarithmic amplifier that processes the output of the light receiving element 2 does not affect the measured value.

(To determine the concentration from the difference in output at optical path lengths Da and Db.) Also, with the advantage of the variable optical path length method that uses one set of light emitting element and light receiving element, the same light emitting element, the same light receiving element, and the same logarithmic amplifier can be used. Since it can be commonly used for measurements at each optical path length Da and Db, there is an advantage that measurement accuracy is greatly improved and costs are reduced by sharing the logarithmic amplifier. Also, 5 in figure 1
represents a mixture of lubricating oil and carbon.

Further, FIG. 2 is a system block diagram for realizing a measurement method based on the principle of the present invention.

Reference numerals 1 and 2 are a light emitting element and a light receiving element, respectively, and the position of the light emitting element 1 is displaced by a driving source 104, and the gap between the two is controlled in two stages.

a calculation unit 10 that calculates the degree of pollution based on the two-stage output of the light-receiving element which has been logarithmically converted by a logarithmic converter in which 100 is 17;
3 is a display section that displays the value. Further, 102 is a timing generator for sampling data to the calculation unit 100 and for sending a drive timing signal for the actuator 104 to the actuator controller 101.

The intent of the present invention is achieved by each of these blocks functioning functionally as fully described.

〔Example〕

A first embodiment based on the present invention is shown in FIG. In this example, in order to control the optical path length in oil into two stages, Da and Db,
This shows an example of displacing the light emitting element 1, in which a piezo stack having a structure in which piezoelectric elements are stacked in many layers is used as a driving source for causing the displacement.

FIG. 4 is a measurement timing chart illustrating the operation of the apparatus shown in FIG.

The following explanation will be given based on FIGS. 3 and 4.

In Fig. 3, 1 and 2 are a light emitting element and a light receiving element, respectively, and the light emitting element (3) is fixed by adhesive or other means into the plunger 6 which is pressed against the left end surface of the piezo stack 7 by a disc spring 10. has been done. The second light receiving element is connected to the body 3 through an optical path length setting ring 5' having a screw inside.
The light emitting element 1 is housed in a plunger 5 which is fixed in position and is disposed opposite the plunger 6 that houses the light emitting element 1 described earlier. The body 3 includes an oil inlet 3' on one end surface in a direction perpendicular to the through hole that houses the plunger;
The other end face is provided with an outflow port 3'', through which the lubricating oil to be measured is introduced between the light emitting element 1 and the light receiving element 2 and discharged to the outside at the same time. Of the plungers 5 and 6, which are sealed so as not to be damaged, the plunger 6, which houses 11 light emitting elements 1, is engaged with the 7 piezo laminated elements without any gaps.

If no voltage is applied to the piezo element 7 in this state, the piezo element remains contracted, and at this time the position of the plunger 5 is adjusted and set using the ring 5' so that a large optical path length is achieved. Next, when a DC voltage is applied to the piezo element 7,
Since the piezo element expands by a certain amount, the optical path length changes from Da to D.
b, and a short optical path length of Db can be realized.

Therefore, at each optical path length of Da and Db, the amount of transmitted light from the light emitting element 1 is received by the light receiving element 2, the outputs are respectively Ia and rb, and the logarithmically converted value is j2og
la and j2oglb, the concentration α is calculated from the equation (3) above by multiplying the difference of (1oglb −7!oglb ) by a constant, α (wt%) = K ′ (j!oglb − JogI
a) Determined by (4).

By repeating this operation continuously and at the same time using a sampling pump etc., the oil to be measured continuously flows in from the 3' inlet and flows out from the 3'' outlet, thereby changing the carbon concentration of the oil to be measured. can be measured continuously.Also, if the measurement interval can be lengthened due to experimental conditions, etc., the piezo element driving interval is lengthened to match the interval, and the light emitting element power source and the logarithmic amplifier of the light receiving element are It is also possible to supply power in synchronization with the measurement interval, thereby greatly extending the life of each component such as the light emitting element and the light receiving element.

In addition, 7' in the figure is 'J-' which applies DC voltage to the piezo element 7.
8 and 9 indicate the input lead wire of the light emitting element 1 and the output lead wire of the light receiving element 2, respectively.

17 is a logarithmic amplification circuit for logarithmically amplifying the output of the light receiving element;
17' and 17'' form a container member for housing this.

FIG. 5 shows a second embodiment of the detection sensor according to the present invention. In the embodiment shown in FIG. 3, a piezo element 7 is used as a driving source for causing the positional displacement of the light emitting element or the light receiving element, whereas the embodiment shown in FIG. 5 uses a solenoid 12. However, there is a big difference.

To explain in detail using FIG. 5, 1 and 2 are a light emitting element and a light receiving element, respectively, and 1' and 2' are plungers for holding and housing each element. In this example, the plunger 1' housing the light emitting element 1 is attracted by the solenoid 12 and moves by a predetermined distance toward the right in the drawing. This provides a large gasoff Db between the pixel elements, and after measuring the amount of light transmitted through the large gap in this state, when the power to the solenoid 12 is cut off, the return spring 15 causes the plunger 1 to ' returns to the position before being sucked. This creates a small gap Da between the pixel elements, and in this state the amount of light transmitted is measured.
The carbon concentration in the oil is measured by performing a comparison calculation with the amount of light transmitted through the large gap described above. Also, 13, 13', 13'' indicate 0 ring,
Reference numerals 16 and 11 are housings that hold plungers 1' and 2' that accommodate the light emitting element and the light receiving element 1.2, and are suitably made of stainless steel or the like. Solenoid 12
The bobbin 12' is fixed to the housing 11 by injection.

The oil to be measured flows in from the oil inlet at 16', passes between the light receiving elements 2 and 1 mentioned above, and the light emitting element.
It flows out from the outlet.

Further, 8 is the input lead of the light emitting element, 9 is the output lead wire of the light receiving element, and 18 is the input lead wire of the solenoid. I7 is an amplifier for logarithmically converting the output of the light receiving element, and 17' is a housing that houses this amplifier.

In this example, since the tip glass portion of commercially available light emitting devices (LEDs) is often in a spherical shape, this tip was ground down to a flat surface with some glass remaining. There is. This increases the accuracy of the gap, increases the amount of transmitted light in a given gap, and increases the S/N ratio of the light receiving element output. This is the same in the embodiment shown in FIG. be.

In the embodiment shown in FIG. 5, the portions that determine the large gap Da and the small gap are indicated by ■, and FIG. 6 shows an enlarged view of the portions. A plunger 1' in the figure moves back and forth through a preset gap ΔD using a solenoid, thereby creating a gap Da.

Db can be realized.

FIG. 7 shows a third embodiment according to the present invention. 3 in Figure 7
The difference between this embodiment and the second embodiment is that in the second embodiment, a solenoid was used to drive the plunger 1' or 2' in which the light-emitting element or the light-receiving element was housed to achieve variable gap. , the third embodiment utilizes a negative pressure source.

In FIG. 7, reference numeral 51 denotes a verofram made of rubber or the like that receives negative pressure, and 50 denotes a case member that fixes the helofram to the housing 11 and houses the return spring 52. Further, a member 53 provided at the tip of the case member 50 is a connector used when piping a negative pressure source with a rubber tube or the like. Other members that are the same as those in the second embodiment shown in FIG. 6 are designated by the same numbers as in FIG. 6, and their explanations will be omitted.

Figure 8 shows the fourth example using a fiberscope.
In this example, only the tip of the measurement part is shown. In this example, 1
The light emitted from the light emitting part passes through the fiberscope 153, is bent at a right angle by the triangular prism 158, passes through the oil film of gear 7 D, is bent again by the prism 159, and is sent to the fiberscope 154. and enters the light receiving element 2. At this time, the gap D is in the state where the cylinder 160 is sucked by the solenoid 152. The thicker portion 160-B of the cylinder will enter the dividing portion 150-A provided in the housing 150, and the gap D will become larger. On the contrary, solenoid 15
2 is turned off, the cylinder 160 is returned to the rear by the return spring 157. As a result, the thin portion 160-A of the cylinder enters into the divided portion 150-A, and the gap becomes smaller due to the spring effect of the entire housing 150. By doing this alternately, large (Da) and small (Db) gears can be realized.

115 is an O-ring for sealing, and other components such as the logarithmic converter section are the same as in the other embodiments. In addition, with this structure, the gap can be set by machining the cylinder member 160, so machinability is good, and the light can be extended using a fiberscope or the like to detect the detection area where the oil film is present and the light emission. Since the light emitting element and the light receiving element can be measured while being separated from each other, when the oil temperature to be measured is particularly high, the light emitting element and the light receiving element do not reach high temperatures, which may extend the life of these elements.

FIG. 9 is an enlarged view of the tip detection section of FIG. 8.

A fifth embodiment of the present invention is shown in FIG. 10 below. In this example, hydraulic pressure from an internal combustion engine or the like is used as the drive source to displace the position of the element, and the measurement is performed only once between the time when the engine is started and the time when the engine is stopped. Regarding this, there is no particular problem in terms of the rate of increase in carbon concentration during one normal run.On the contrary, this is because the light emitting element stops emitting light after a certain measurement time immediately after the engine starts, and especially when the oil Avoiding light emission when the temperature is high may extend the life of the light emitting element.

First, in FIG. 10, reference numeral 203 is a bellofram that receives the hydraulic pressure. When the engine starts and the oil pressure increases, a member 204-1 that houses the light emitting and light receiving elements 1.2 and an inner end of the bellofram 203 are connected to each other. Member 2 fixed to 204-1
Together with 04-2, it overcomes the return spring 202 and moves to the right by a predetermined distance ΔD. This results in no oil pressure up to that point and is pushed to the left by the return spring, resulting in a small gap 2D (Da = 2D
), the permeation amount measurement state was changed to the member 20 that houses each element as the velofram is moved by hydraulic pressure as described above.
4-1 etc. also moves to the right by ΔD, the gap becomes 2D+2ΔD (Db), and the amount of transmission through the large gear can be measured with a light receiving element. In this way, the carbon concentration is determined by performing predetermined conversions and calculations from the light receiving element outputs at each of the two gaps.

In the figure, 200 and 201 are housing members that incorporate the above-mentioned velofram, the element housing member 204, the return spring 202, etc., and 207 are the holding member 208 of the prism 206 for refracting the light 1806, and the element housing member 2.
The oil passages 202-2 provided between the housing member 200 and the oil passages 202-2 communicate with each other through oil passages provided in the housing member 200.

200-1 is the hydraulic pressure of the internal combustion engine in the bellofram chamber 203-1.
This is an introduction hole for introducing the

Further, 205 is an input lead portion of the light emitting element and an output lead portion of the light receiving element.

The other parts are the same as those in other embodiments, and therefore will not be described here.

Therefore, with such a configuration, by attaching the detection section to the hydraulic passage section of the internal combustion engine, measurement can be performed without requiring a special drive source, which is highly advantageous. In addition, as an example of electrical processing in the calculation section, the light receiving element output when there is no oil pressure for about 1 second and the gap is small at the same time as the engine starts is logarithmically converted and stored, and then it is assumed that the oil pressure has increased and the output is stored after the engine starts. A conceivable method is to logarithmically transform and store the output of the light receiving element several tens of seconds later as the output when the gear is large, and perform predetermined calculations from these values to calculate the carbon concentration.

In the final example shown in FIG. 11, the prism used in the embodiment shown in FIG. The setting can be set to 2 compared to the embodiment shown in FIG. 10, making it possible to measure even higher carbon concentrations. Other points are the same as those in FIG. 10, so explanations will be omitted.

In addition to these embodiments, when an internal combustion engine is used as a driving source for displacing a light emitting element or a light receiving element, a large temperature difference occurs between cooling water temperature and oil temperature between normal operation and non-operation. Therefore, there is no problem with a wax-filled actuator that utilizes this temperature difference to cause displacement by thermal expansion of wax, for example. Furthermore, it is quite possible to form a spring or the like using a shape memory alloy that has recently begun to be used, and operate this shape memory alloy spring using the aforementioned temperature difference, thereby replacing these driving sources. In normal vehicle driving patterns, there are no particular problems with actuators that utilize these temperature differences in terms of the progress of contamination even if only one measurement is made per driving, and compared to solenoid or PZT methods, An advantage is that actuator control circuitry can be eliminated or reduced.

〔Effect of the invention〕

According to the present invention, dirt on the surface of the light emitting element and the light receiving element;
Accurate oil pollution level can be detected without being affected by changes over time or temperature.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the principle of the present invention, Fig. 2 is a system block section of the oil pollution sensor according to the invention, Fig. 3 is a diagram showing the first embodiment of the oil pollution sensor according to the invention, and Fig. 4 is a diagram showing the first embodiment of the oil pollution sensor according to the invention. 5 is a diagram showing a second embodiment of the oil pollution sensor according to the present invention; FIG. 6 is a partially enlarged view of the embodiment shown in FIG. 5; and FIG. 7 is a diagram showing the second embodiment of the oil pollution sensor according to the present invention. FIG. 8 is a diagram showing a fourth embodiment of the oil pollution sensor according to the present invention; FIG. 9 is a partially enlarged view of the embodiment shown in FIG. 8; FIG. The figure shows a fifth embodiment of the oil pollution sensor according to the present invention, FIG. 11 shows a modification of the fifth embodiment shown in FIG. 10, and FIG. 12 shows a conventional light transmission type pollution sensor. FIG. 13 is a diagram showing the head portion, and FIG. 13 is a diagram showing the emission intensity temperature characteristics of the light emitting element. In the figure, 1... Light emitting element, 2... Light receiving element, 17... Log amplifier.

Claims (1)

[Claims] 1. It has a light emitting part and a light receiving part that receives light from the light emitting part, a gap is provided between the light emitting part and the light receiving part, and when this is immersed in lubricating oil, In an oil pollution level detection device that is equipped with a detection section that allows lubricating oil to be introduced into the gap and measures the degree of contamination of the lubricating oil based on the output from the light receiving section, the light emitting section, the light receiving section, or its 1. An oil pollution level detection device comprising a driving section for displacing both of the light emitting section and the light receiving section to realize two types of gaps between the light emitting section and the light receiving section. 2. Logarithmic conversion means for logarithmically converting the output values obtained from the light receiving sections in the two types of gaps, and calculating the difference between the logarithmically converted values, calculating the degree of pollution from this value, and displaying the output. The oil pollution level detection device according to claim 1, further comprising data processing means for performing the following. 3. The oil pollution level detection device according to claim 1, wherein the tip of the window portion made of a transparent body in contact with the lubricating oil of the light emitting element in the light emitting portion is flat. 4. The oil pollution level detection device according to claim 1, wherein the window portion made of a transparent body in contact with the lubricating oil of the light receiving element in the light receiving portion has a flat shape. 5. Claim 1, in which the driving section comprises a piezoelectric element
The oil pollution level detection device described in section. 6. The oil pollution level detection device according to claim 1, wherein the drive section comprises a solenoid, a plunger that is attracted by energizing the solenoid, and a spring that acts against the attraction force. 7. The oil pollution level detection device according to claim 1, wherein the drive section comprises a negative pressure source and a verofram receiving the negative pressure. 8. The light emitted from the light emitting part passes through the first fiberscope and is bent at a right angle by a first triangular prism to reach the gap, and the light passing through the gap is bent at a right angle by a second triangular prism. and reaches the light receiving section via a second fiberscope, and the direction of the light passing through the first fiberscope is substantially parallel to and opposite to the direction of light passing through the second fiberscope. The oil pollution level detection device according to scope 1. 9. The first fiber scope and the first triangular prism are held by a first elastic member, the second fiber scope and the second triangular prism are held by a second elastic member, and the driving The section includes a solenoid, a return spring, and a cylinder, and the cylinder is inserted between the first elastic member and the second elastic member and is inserted between the first triangular prism and the second triangular prism. and a portion that enters between the first elastic member and the second elastic member to create a second gap between the first triangular prism and the second triangular prism. energizing the solenoid attracts and moves the cylinder to realize the first gap, and de-energizing the solenoid causes the cylinder to be pulled by the return spring. 9. The oil pollution level detection device according to claim 8, wherein the second gap is realized by moving the body, and the first and second gaps correspond to the two types of gaps. 10. The oil pollution degree detection device according to claim 1, wherein the drive section is a bellows frame that receives hydraulic pressure of an internal combustion engine lubricated by the lubricating oil. 11. The oil pollution level detection device according to claim 1, wherein the drive unit utilizes a change in volume or shape with temperature change.