KR20060087293A - Ph-sensor for the measurement of the concentration of the proton in the engine oil to detect the extent of the degradation of the engine oil - Google Patents

Abstract

The present invention measures the concentration of hydrogen ions in oil generated by the deterioration of the engine oil due to the difference in electromotive force (voltage) between the indicator electrode and the reference electrode using the hydrogen ion selective membrane electrode as the indicator electrode. The present invention relates to an internal combustion engine having an apparatus for diagnosing automobile engine oil by analogy and a driving algorithm for implementing the same. The present invention provides a convenient apparatus and method for allowing a user to scientifically recognize an engine oil change time.

Automotive, engine oil deterioration, hydrogen ion, hydrogen ion selective membrane

Description

PH-sensor for the measurement of the concentration of the proton in the engine oil to detect the extent of the degradation of the engine oil}

Figure 1: Schematic structural diagram of the deterioration measuring instrument of engine oil

Figure 2: Mounting in the Car Engine

3: Structure of Indicator and Reference Electrodes with a Body of Hemispherical Hydrogen Ion Selective Membrane

4 is a structural diagram of a reference electrode and a reference electrode in which a hemispherical hydrogen ion selective membrane is bonded to a glass tube or a plastic tube

FIG. 5: Structure of Indicator and Reference Electrodes with One Body of Planar Hydrogen Selective Membrane

6: Structure diagram of indicator electrode and reference electrode in which planar hydrogen-ion selective membrane and glass tube or plastic tube are bonded with sealing material

[Description of Drawing]

10-indicator electrode 11-hydrogen ion selective film

12-electrode 13-glass tube and plastic tube

14-Buffer 15-Sealed Tube

20-reference electrode 21-barrier film

22-electrode 23-salt bridge

24-Potassium Chloride Solution 30-Sealing Membrane

40-conductor

100-Hydrogen ion sensor 200-Engine room

Although automotive engine oils form a big market, the method of deciding when to change the engine oil is to touch it with human hands, visually judge the color, or record the mileage when changing the oil in the car account book. In the non-scientific way of judging or the mileage interval according to the oil change recommended time and mileage recommended by the automobile company, the exchange is being performed.

According to this method, not only the engine oil loss but also the environmental pollution caused by the waste oil are severe, and the regular inspection cost is excessively consumed. Since there is a case of shortening the life of the engine, it is required to develop a method for knowing the exact time of replacement of the engine oil.

Therefore, the present invention solves the above problems by using the electrochemical method as a result of the effort to solve the above problems to complete the present invention.

Overseas efforts have been made to monitor the state of engine oil in real time since the early 80s, but recently, the electrical characteristics of engine oil have been measured by measuring the electrical characteristics of engine oil at the level of measuring the viscosity or color of the engine oil and converting it into an electrical signal. Research to detect the condition is ongoing. In the U.S. patent there are methods using the electrical conductivity and dielectric constant of the oil. The change in electrical conductivity or dielectric constant is not caused by a single physical change in the engine oil, but is caused by various physical and chemical changes, so it is easy to obtain information on the engine oil change due to various causes. Have. However, electrical conductivity and dielectric constant are dependent on temperature, so a compensation method for the influence of temperature is needed. Especially in the case of engine oil, the influence of temperature should be taken into account because the temperature is in the wide range of 70-150 ℃ when the vehicle is in operation. In addition, until now, devices for measuring electrical conductivity or dielectric constant have a disadvantage in that they are not easy to mass production because they are in the form of bulky mechanical structures. In addition, it is possible to measure the deterioration of the engine oil by measuring the flow rate path change using a magneto resistor sensor, and measuring the total base number (TBN) and total acid number (TAN), but this method also has many problems for mounting in automobiles. This was found.

In Korea, rather than using the electrical characteristics of the engine oil, it detects only one physical characteristic of the engine oil such as oil level indicator, mileage, turbidity, and viscosity, and converts it into an electrical signal. Since engine oil deterioration is not a change of one physical property but is accompanied by various physical and chemical changes, such a measurement that depends on one physical property is far from accurate.

The first object of the present invention is to develop a measuring instrument that can determine the optimum time for oil change by measuring the deterioration state of automobile engine oil.

The second object of the present invention is to extend the service life of an automobile engine by enabling the driver to effectively change oils by setting an engine oil change plan by developing the measuring instrument.

A third object of the present invention is to provide a method for diagnosing deterioration of engine oil using the measuring instrument.

It is another object of the present invention to provide a new algorithm for diagnosing deterioration of the engine oil.

The present invention relates to a technique for monitoring timing of vehicle engine oil change in an electrochemical manner.

In other words, automotive engine oil generates water and acidic combustion by-products in the oil due to low temperature operation, incomplete combustion of fuel, wear and corrosion of the engine, and the like during engine operation. Therefore, it is possible to present a criterion for judging the degree of deterioration (degeneration) of the engine oil as the degree of oxidation of the oil. Accordingly, in the present invention, a hydrogen ion selective membrane electrode is used to detect the concentration of hydrogen ions in the oil. It is to measure the aging state of oil and to determine the exact time of oil change based on this.

As described above, the technique for determining the degree of oxidation of the engine oil by the hydrogen ion selective membrane electrode has a wide range of pH that can be measured, and a colored or suspended colloid containing engine oils with detergents and various dispersing additives. It is an advantage that the measurement is possible without any limitation.

Therefore, it is possible to solve the disadvantages of the conventional engine oil deterioration detection method, which is easy to be inaccurate and subjective judgment by allowing the driver to measure the deterioration of oil easily and quickly through the measuring device devised in the present invention, and does not change the structure of the engine. It is possible to infer the degree of deterioration of the engine without being able to detect the degree of degeneration as a relative value by calibration, depending on the type of oil.

The present invention comprises an electrode composed of an electrode for measuring the change in hydrogen ion concentration of the engine oil, a buffer solution and a hydrogen ion selective membrane surrounding the hydrogen ion selective membrane and selectively reacting with the hydrogen ion, the electrode and the electrolyte well known the potential value of the half cell And an oil pH meter including a reference electrode made of a blocking film protecting the insulating film, a conductive wire connecting the indicator electrode and the electrode of the reference electrode, and an engine oil composed of a sealing plate integrally sealing the indicator electrode and the reference electrode. .

An embodiment of the present invention can be configured as shown in FIG. 1. That is, in order to measure the concentration of hydrogen ions present in the engine oil without being disturbed by other ions, it is irrelevant to the measurement oil as shown in FIG. 1 by using a membrane electrode (indicative electrode) 10 selectively reacting with hydrogen ions. It constitutes an electrochemical measurement system connected to the reference electrode 20 to fix the voltage. Herein, the concentration of hydrogen ions is measured by the voltage between the indicator electrode 10 and the reference electrode 20. The reference electrode on the right side is the reference electrode voltage standard, similar to the earth ground used in an electric circuit. Play a role.

The indicator electrode 10 may be a glass tube or a plastic tube composed of a hydrogen ion selective membrane 11 that selectively reacts only with hydrogen ions in oil as the whole or part of the indicator electrode 10, and may be formed of another glass tube or plastic. It can be used in conjunction with the tube 13. At this time, the buffer solution 14 (for example, hydrochloric acid (HCl) aqueous solution) of the prescribed concentration is put into the tube, and the electrode 12 (for example, silver / silver chloride (Ag / AgCl) electrode or sensitization) contained therein is added thereto. (Hg / HgCl) electrode) makes the concentration of hydrogen ions (H ⁺ ) constant.

 The reference electrode 20 serving as the reference electrode 10 is a caramel reference electrode whose half cell potential value is well known (made by putting mercury in a solution 24 saturated with mercuric chloride and containing a constant concentration of potassium chloride). Electrode) or a silver / silver chloride (Ag / AgCl) reference electrode (a silver electrode saturated with silver chloride and immersed in a constant concentration of potassium chloride solution 24), and can be made of a glass tube or plastic covering the electrode 22 and the electrolyte. It is to be protected by a blocking film 21, such as a tube, it may be provided with a salt bridge 23 for a constant potential.

When the indicator electrode and the reference electrode configured as described above are simultaneously immersed in engine oil as shown in FIG. 2 and the voltage between the two electrodes is measured using a voltmeter, the voltage value is

Electromotive force (EMF) = indicator electrode potential (E _s ) _-reference electrode potential (E _ref ) (1)

It is expressed as Here, the potential of the indicator electrode is again the concentration of different hydrogen ions in the solution in contact with both sides of the interfacial potential (E _W ) generated between the internal electrode (eg, silver / silver chloride electrode) and the electrolyte and the hydrogen-ion selective membrane. It is composed of boundary potentials (E _b ) generated and asymmetric potential constants (E _O ) that appear unevenly on most membrane electrodes. If you express this mathematically

Indicator electrode potential (E _S ) = E _W + E _b + E _O (2)

Becomes

In addition, the potential of the reference electrode is the reference potential (E _r ) generated at the interface between the internal electrode and the electrolyte and the contact potential (E) caused by a salt bridge inserted to prevent mixing of the electrolyte and oil in the reference electrode. _j ) If you express this mathematically

Reference electrode potential (E _ref ) = E _r + E _j (3)

Becomes Usually, in practice, the electrolyte material of the reference electrode selects a solution having no potential difference between salts, and in this case, E _j = 0 in Equation (3). Therefore, substituting equation (2) and equation (3) into equation (1)

EMF = E _W + E _b + E _O -E _r -E _j (4)

Becomes

Where E _W and E _r are constants with constant values because the internal electrodes in each cell and the components of the aqueous solution in contact with them are fixed, and E _O and E _j are nonuniform characteristics of the cell manufacturing process. It is a constant which comes as a manufacturing constant. However, E _b has the following relation depending on the concentration of hydrogen ions adsorbed on both sides of the hydrogen ion selective membrane.

와

는 각각 기체상수(1.987 cal/도-몰), 절대온도(K), 패러데이 상수(96487 쿨롬/몰), 그리고 수소이온 선택막 내면의 수소이온의 활동도와 수소이온 선택막 밖의 면의 수소이온의 활동도이다. 수소이온의 활동도는 수소이온의 농도에 정비례하는 관계를 가지고 있어 Where R, T, F,

Wow

Are the gas constant (1.987 cal / degree-mole), absolute temperature (K), Faraday's constant (96487 coulomb / mole), and the activity of hydrogen ions on the inner surface of the hydrogen-ion selective membrane and the hydrogen ions on the surface outside the hydrogen-ion selective membrane, respectively. It is also activity. The activity of hydrogen ions has a relationship directly proportional to the concentration of hydrogen ions

와 [H⁺]는 각각 비례상수와 수소이온의 농도(몰/리터)이다. 그런데 지시전극 내에 있는 전해질의 농도는 일정하므로 식(5)는 다시 It can be expressed as here

And [H ⁺ ] are proportional constant and concentration of hydrogen ion (mol / liter), respectively. However, since the concentration of the electrolyte in the indicator electrode is constant, Equation (5)

는 지시전극의 전해질에 따른 상수이다.It is simply expressed as a function of the hydrogen ion concentration in the sample oil that the indicator electrode is in contact with. here

Is a constant depending on the electrolyte of the indicator electrode.

 In summary, equation (4)

The voltage measured between the indicator electrode and the reference electrode by dipping the measurement system configured as shown in FIG. 1 into the engine oil is proportional to the hydrogen ion concentration of oil in contact with the indicator electrode.

2 shows an example of a diagram in which the pH meter 100 of the present invention is installed in an engine room of an automobile. By inserting the pH meter 100 in a predetermined position of the engine room 200, it is possible to check the degradation of the engine oil by measuring the pH of the real-time oil. For example, unused fresh oil usually has a pH of about 7.0, while oil that uses about 5000 km has a pH of about 6.2. Therefore, in case of setting the point when the pH is 6.2 as the replacement time, the internal circuit can be connected to the driver's seat so that the driver knows the time to replace it at the driver's seat when the set value is reached. By inserting the engine independently and covering the electrode terminal with a cap, it can be used by adopting various methods such as taking a cap off with a pH meter and connecting and measuring it regularly during maintenance.

3 is a case where a hemispherical shape of a lower surface of the indicator electrode 10 is formed so that the hydrogen ion selective film 11 can serve as a support for the buffer solution 14 in the indicator electrode 10.

FIG. 4 shows another embodiment of the present invention, in which only the lower surface of the indicator electrode 10 is made of a hemispherical hydrogen ion selective film 11, and a portion surrounding the remaining electrolyte and the electrode is made of a glass tube and a plastic tube 13. One embodiment of forming a barrier film to increase durability is shown.

FIG. 5 illustrates another embodiment of the present invention in which the lower surface is formed in a planar shape so that the hydrogen ion selective film 11 can serve as a support for the buffer solution 14 in the shape of the indicator electrode 10.

FIG. 6 shows that the planar hydrogen ion selective membrane 11 at the bottom and the glass tube or plastic tube 13 on the wall surface are joined using a sealant 15 to easily bond the selective membrane 11 to the glass tube or plastic tube 13. One embodiment of the structure of the indicator electrode 10 and the reference electrode 20 is shown, and thus the present invention can be used in various forms.

In an embodiment of the present invention, when the apparatus of FIG. 1 is inserted into the engine room, the pH of the new oil was 7.0, but it was deteriorated as 6.2 as a result of measuring the concentration value of hydrogen ions of the oil after running 5000 km. In other words, it can be seen that the concentration of hydrogen ions in the oil is increased by about 10 times after running 5000 km.

When using an electrochemical measuring instrument using a hydrogen ion selective membrane electrode designed in the present invention can be embedded in the engine is always covered in the oil so that the detection is possible in real time and accurately know the timing of replacement of engine oil for automobiles, In addition to extending the life of the vehicle due to the protection of the engine, it is expected to improve the damage to the environment caused by incomplete combustion by driving the engine at all times while maintaining the performance of the engine oil.

Claims (7)

It is composed of an indicator electrode equipped with a hydrogen ion selective film to measure the change of hydrogen ion concentration in the engine room and a reference electrode to fix the voltage. Hydrogen ion sensor to measure. The method of claim 1, The hydrogen ion selective membrane is a hydrogen ion sensor, characterized in that the glass membrane or plastic membrane. The method of claim 1, The hydrogen ion selective membrane of the indicator electrode to completely surround the electrode and the buffer solution, or to cover a portion of the engine oil hydrogen ion sensor. The method according to any one of claims 1 to 3, The electrode used as the internal electrode of the indicator electrode is a hydrogen ion sensor, characterized in that the Ag / AgCl electrode. An automobile internal combustion engine capable of measuring the hydrogen ion concentration of engine oil by inserting the hydrogen ion detection sensor of any one of claims 1 to 3 on one side of an automobile engine room and measuring the potential difference from the outside. The method of claim 5, The measurement of the potential difference is provided with an internal circuit for measuring the pH manually by connecting to the exposed terminal of the hydrogen ion sensor or by transmitting to the driver as an electrical signal when detected below the set hydrogen ion concentration is detected. Automotive internal combustion engine that can measure the hydrogen ion concentration, characterized in that. The hydrogen ion sensor according to any one of claims 1 to 3 is inserted into a certain portion of an engine of an internal combustion engine of an automobile, and the degree of deterioration of the lubricating oil (engine oil) is measured by measuring the concentration of hydrogen ion (pH). How to measure the hydrogen ion concentration of the engine oil to determine the.

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