JPS6252124B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a device that can accurately and reliably warn of the deterioration status of engine oil. Conventionally, the properties of lubricating oils such as engine oils and transmission oils used in mechanical friction parts of automobiles and the like gradually change during the course of their use, resulting in deterioration of their lubrication performance. This deterioration in lubricating oil performance not only impairs lubricity but also causes oxidation of mechanical mechanisms. Therefore, conventionally, in cars, etc., the lubricating oil has been changed after driving a certain distance, or the degree of performance deterioration has been determined sensually from the color and texture of the lubricating oil (touched with the fingertips), and the measures have been taken accordingly. This led to careless exchanges. Furthermore, as a measure of the performance deterioration of lubricating oil, the viscosity of the lubricating oil, the acid value, base value, residual carbon, and insoluble content in the lubricating oil have been quantitatively measured. However, the former is a sensual evaluation by humans;
It is not possible to determine whether the performance of the lubricating oil has deteriorated. The latter is a chemical measurement method, which requires a large amount of time for quantitative analysis and requires a complicated measuring instrument, so it is not practical. Furthermore, as an electrical measurement method for increasing residual carbon and dielectric substances contained in the lubricating oil, there is also a means of measuring the electrical conductivity and dielectric constant of the lubricating oil to evaluate the performance of the lubricating oil. However, changes in the electrical conductivity or dielectric constant of lubricating oil vary greatly depending on the conditions of use of the vehicle, etc., and the components of additives contained in the lubricating oil. However, it was not possible to accurately judge the performance deterioration of lubricating oil. The present invention solves the above-mentioned conventional drawbacks, and measures the deterioration of engine oil by applying a pulse voltage to a pair of electrodes facing the engine oil of automobiles, etc., and measuring the transient response characteristics of the engine oil. The main object of the present invention is to provide an engine oil deterioration warning device that can detect an increase in conductive substances and dielectric substances that are the cause. That is, an object of the present invention is to provide at least a pair of electrodes arranged in an oil container or the like so as to be exposed to engine oil, a means for measuring the temperature of the engine oil, and an electrode that operates according to the output of the temperature measuring means. a voltage source that applies a pulse voltage of a constant amplitude and a constant time duration to the electrodes; and a current detection means that detects a transient response current of engine oil between the electrodes;
processing circuit means for measuring a current peak value at an arbitrary position of the transient response current and a current change amount within a certain time period of the transient response current, and measuring a ratio between the current peak value and the current change amount; An object of the present invention is to provide an effective alarm device that can be mounted on a vehicle and includes a display means that displays the performance status of engine oil based on the output of a circuit means, and that issues a warning such as the time for oil change depending on the deterioration state of the engine oil. . Another object of the present invention is to input a battery voltage or a primary voltage of an ignition coil in an ignition device of an automobile as a voltage source for generating the pulse voltage, and generate a pulse of a constant amplitude and a constant time width. An object of the present invention is to provide an engine oil deterioration warning device characterized in that it is a power source means for converting into voltage. Furthermore, an object of the present invention is to provide, in the display means,
We set a judgment standard value according to the type of engine oil, and when changing the oil, we memorize the initial performance value of the oil, and no matter what type of oil it is,
It is an object of the present invention to provide an engine oil deterioration warning device characterized by being provided with a display means that allows the state of performance deterioration to be accurately determined. Another object of the present invention is that, in the display means, based on the initial performance value of the engine oil,
It is an object of the present invention to provide an engine oil deterioration warning device characterized in that it compares the measured value of the oil outputted from the processing circuit means during the usage process and displays the remaining life span or usage limit of the oil. Another object of the present invention is to provide an engine oil, characterized in that the electrode is made of a material such as aluminum or stainless steel that is not corroded by acids or bases contained in the oil because it is exposed to the engine oil. The object of the present invention is to provide a deterioration warning device. The present invention also provides sensor means comprising at least a pair of electrodes facing the engine oil to be measured and a temperature sensor for detecting the temperature of the engine oil; temperature detecting means for determining whether the engine oil is in a state of deterioration; and energized by the output signal of the temperature detecting means and a signal indicating operation of an engine starting switch, and emitting a measurement signal to measure the state of deterioration of the engine oil. a timing circuit means; a power supply means that is energized by the output of the timing circuit means and generates a pulse voltage of a constant amplitude and a constant time duration in order to apply a pulse voltage to the electrode portion of the sensor means; current detection means for detecting a transient response current of engine oil interposed between the electrodes by applying a pulse voltage from a power supply means to the electrodes of the sensor means; and a current peak at an arbitrary position of the transient response current. value, detects the amount of current change within a certain period of time,
processing circuit means for measuring a ratio value between the current peak value and the current change amount; comparing and determining the current peak value and the ratio value output from the processing circuit means with a determination reference value to arbitrarily set the current peak value and the ratio value; An engine oil deterioration alarm comprising a determination circuit means for outputting a determination result according to the deterioration state of the engine oil, and a display means for displaying the deterioration state of the engine oil according to the output of the determination circuit means. It is a device. According to the alarm device of the present invention having the above configuration,
Since it is possible to accurately measure the properties of engine oil for automobiles, etc., as well as its contamination status and usage limits, it can greatly contribute to society's conservation of petroleum resources. Furthermore, by installing the warning device of the present invention in a vehicle, the driver himself/herself can sense the condition of the engine oil, leading to improved performance, safety, and even fuel efficiency of the vehicle, which is extremely effective. . Next, the basic principle and specific examples of the engine oil deterioration warning device of the present invention will be described. The basic principle of the present invention will be explained based on FIG. A dielectric substance such as engine oil facing a pair of electrodes is shown in equivalent circuit 1 in Figure 1a,
Internal resistance γ and relative dielectric constant ε of engine oil
It is expressed as capacitance C by _s . In this equivalent circuit 1, from the power supply E through the switch S,
When a step voltage V is applied, a transient response current of i≈V/γ ₀ exp(−t/γ ₀ C)+V/γ) flows through the equivalent circuit 1. This current i will be explained in detail using the current waveform shown in FIG. 1b. Immediately after the voltage V is applied to the pair of electrodes, a current of V/γ ₀ flows due to the circuit resistance γ ₀ , but the current decreases exponentially as time passes. However, after that, a steady current E/γ that shows a slow change flows. This steady current is generated by the resistance value γ of the dielectric material when a pulse voltage is applied to the dielectric material. Here, γ and C are variables depending on the performance of the engine oil, and vary greatly depending on its type and properties. For example, in the transient response current i, the A characteristic is when γ is small and C is large, and the B characteristic is when γ is large and C is small. In A characteristic, if the initial value of the transient response current within a certain period of time is ip ₁ and the current after a certain period of time is im ₁ , ip ₁ depends on γ in the engine oil, that is, the conductivity, and , the change value of the current i, i.e. ip ₁ −im ₁ , depends on the change in the electrical conductivity of the engine oil. Therefore, if ip ₁ is large, there will be a lot of metal powder and residual carbon in the oil.
Due to high conductivity, electrical resistance is low, ip ₁ −
When im ₁ (hereinafter denoted by variation △i) is large,
Small change in electrical conductivity in oil, electrical capacity C
can be said to be small. From the above transient response current characteristics, when comparing A characteristic and B characteristic, we find that Γ ip ₁ > ip ₂ Γ ip ₁ − im ₁ < ip ₂ − im ₂ From the relationship, A characteristic engine oil is more conductive than B characteristic engine oil. It can be determined that the ratio is large and the amount of change is small. An example of measuring the transient response current in this engine oil using actual engine oil is shown in the second example.
As shown in the figure. Figure 2 a shows the current characteristics of unused oil, b shows the current characteristics after running 9000 km, and c shows the current characteristics after running 15000 km. Determining the above ip and ip-im, that is, △i, from each current waveform, we get

[Table] It can be seen that ip increases in proportion to the distance traveled, and △i decreases in proportion to the distance traveled. The increase in IP is thought to be due to the contamination of metal powder and the increase in residual carbon in engine oil during its use, resulting in a gradual increase in electrical conductivity. Furthermore, the decrease in Δi is considered to be due to the gradual decrease in the change in the electrical conductivity of the oil itself due to the influence of moisture, insoluble matter, etc. during its use. In other words, the peak current value at any position in the transient response current of a dielectric material is determined by the properties proportional to the conductivity in the dielectric material, such as metal powder, residual carbon, and insoluble matter contained in the lubricating oil. It depends on the amount of charged particles generated when molecules of additives used to improve the performance of lubricating oil dissociate or ionize. Therefore, an increase in ip is a measure of a lubricant's performance deterioration. Furthermore, by comparing the IP values of a plurality of dielectric materials, it can be used as a means to determine the type and properties of the dielectric materials. Furthermore, the amount of current change △i within a certain period of time from the peak current value ip at an arbitrary position in the transient response current of a dielectric material has a property proportional to the change in conductivity of the dielectric material, for example, in lubricating oil such as engine oil, During its use, several molecules of metal powder, water, insoluble matter, etc. mixed into the lubricating oil combine to form large colloidal particles, so the charged particles generated by the dissociation or ionization of the particles are released into the lubricating oil. It is thought that this makes it difficult for the lubricating oil to move inside the lubricating oil, and the apparent change in the electrical conductivity of the lubricating oil itself decreases, resulting in a decrease in the amount of current change Δi. Therefore, a decrease in Δi is determined to be due to the presence of large colloidal particles in the lubricating oil due to foreign matter contamination, and serves as a means of indicating a decrease in the performance of the lubricating oil. Further, by comparing Δi of a plurality of dielectric materials, it can be used as a means for determining the type and properties of the dielectric materials. Therefore, in engine oil, the ip is large,
It can be determined that the smaller Δi is, the lower the performance is. Therefore, the IP depends on the conductivity of the engine oil.
and △i, which depends on the change in conductivity, are calculated as ip/△i, and the ratio is found as shown in Table 1.
Since the ratio increases in proportion to the period of use (mileage) of the oil, this value is an effective means of evaluating the performance of the oil. Based on the above basic principles and numerous experimental considerations, at least one pair of electrodes is provided, the interior of the oil container is arranged so that the engine oil is exposed to the electrodes, and a pulsed voltage is applied to the electrodes. By measuring the peak value of the transient response current flowing between the electrodes during the period during which the pulsed voltage is applied, the amount of change within a certain period of time, and measuring the ratio between the peak value and the amount of change. , it becomes possible to know the degree of deterioration of engine oil very easily. Hereinafter, specific embodiments of the engine oil deterioration warning device of the present invention will be described in detail. FIG. 3 shows the basic configuration of the alarm device of this embodiment. The device of this embodiment includes a sensor means 1 consisting of at least a pair of electrodes disposed in an oil container (usually referred to as an oil pan) of an engine so as to be exposed to engine oil, and a temperature sensor to detect the oil temperature. have This device converts the output signal of the temperature sensor in the sensor means 1 into a temperature signal with a cable means 9 connecting the sensor means 1 and an alarm device installed near the driver's seat in an automobile etc., and converts the output signal of the temperature sensor in the sensor means 1 into a temperature signal. Temperature detection means 2 which issues a measurement finger signal when the temperature is within a predetermined temperature, and timing circuit means 3 which receives the output of the temperature detection means 2 and an engine starting switch, that is, a key signal, and issues a timing signal to control measurement. and has. Further, the device is energized by the output of said timing circuit means 3 to generate a pulse voltage of constant amplitude and duration, and to apply said pulse voltage to the electrodes in said sensor means 1. and current detection means 5 for detecting a transient response current generated by a transient response of oil interposed between the electrodes when a pulse voltage is applied to the electrodes in the sensor means 1. In addition, the present device includes a processing circuit means 6 for determining a current peak value at an arbitrary position of the output of the current detecting means 5, a current change amount within a certain period of time, and a ratio between the current peak value and the current change amount.
and a determination circuit means 7 that compares and determines the deterioration state of the engine oil with a reference value according to the output of the processing circuit means 6, and displays the deterioration state of the engine oil to the driver based on the output of the determination circuit 7. It is composed of a display means 8 and an alarm device. The specific configuration, function, and operation of each element of this device will be explained below with reference to FIGS. 4, 5, and 6. FIG. 4 shows a preferred embodiment of the sensor means 1 of the engine oil deterioration warning device according to this embodiment. In FIG. 4a, the sensor means 1 includes a jig 1C, at least a pair of electrodes 1a disposed insulatively on the jig 1C, a temperature sensor 1b, and a combination of the electrodes 1a and the temperature sensor 1b with an alarm device. The sensor means 1 is composed of a connector 1d to
is attached to the oil pan OP of the engine, and the electrode 1a and temperature sensor 1b are made to face the oil O. FIG. 4b shows a cross section of the sensor means 1, and FIG. 4c shows the structure of the electrode 1a. The electrode 1a and the temperature sensor 1b are embedded in an insulating (for example, ceramic) fixed part 1e, and the jig 1
It becomes stuck inside C. The electrode 1a has a flat plate electrode structure as shown in FIG. It is electrically connected to the connecting portion 1g with the external connector 1d and led out by lead wires 1f ₁ and 1f ₂ . Similarly, the lead wire portion of the temperature sensor 1b is buried in the fixed portion 1e, connected to the connection portion 1g, and led out by a lead wire _1f3 . When the sensor means 1 having such a configuration is attached to the oil pan OP of the engine, it can be easily applied to the engine if it can be attached to the drain plug part used when changing the oil. Furthermore, since the sensor means is easy to attach and detach, when the engine oil deterioration warning device of this embodiment displays an oil change request, the sensor means 1 is removed and the oil is replaced. Dirt on the electrode 1a of the sensor means can be cleaned at the same time, making maintenance easier. Therefore, it is possible to ensure both reliability and durability of the sensor means 1. Next, the alarm device will be explained with reference to FIGS. 5 and 6. The temperature sensor 1b of the sensor means 1 is connected to the temperature detection means 2 by a lead wire _1f3 .
The temperature detection means 2 includes a temperature detection circuit 40 for converting the output of the temperature sensor 1b into a temperature signal, and a discrimination circuit 41 that issues a measurement command signal when the engine oil is in a predetermined temperature range. According to this configuration, no matter what the outside air temperature and engine oil temperature are under the initial conditions of the engine, such as cold or warm seasons, the temperature of the engine oil reaches a predetermined temperature by warming up the engine or the like. Once reached, a command signal can be issued to measure the state of oil deterioration. Here, the predetermined temperature of engine oil means that in order to apply the basic principle of the present invention to engine oil,
This is the temperature range in which maximum sensitivity and high reliability can be obtained, for example in car engine oil.
According to experimental facts, it is within the range of 5°C to 70°C. Further, in the above temperature range, the optimum oil temperature is around room temperature. Next, the measurement command signal issued from the temperature detection means 2 is inputted to the timing circuit means 3. The timing circuit means 3 consists of a timing circuit 30 and a reset circuit 31, and is operated by the measurement command signal and a key signal generated by operating the engine start switch. According to this configuration, when the engine start switch is turned on or the engine is started, a key signal is input by operating the start switch, and a power source (not shown) is activated to operate the alarm device. Set to operational state. In this operating state, when the engine oil measured by the temperature detection means 2 _{is within a predetermined temperature, a P 1 signal} ( 6th
Figure-a) is emitted. Further, after a certain time _T1 delay from the _P1 signal, a _P2 signal (FIG. 6-b) having a certain time width _T2 which energizes the processing circuit means 6 is generated. Furthermore, the output of the timing circuit 30, that is, P ₂
A P ₃ signal (FIG. 6-c) and a P ₄ signal (FIG. 6-d) having a fixed time width T ₃ from the end of the signal are generated from the reset circuit 31 and input into the processing circuit means 6, respectively. . Next, the power supply means 4 comprises a power supply 41 which generates a constant DC voltage, and a switch circuit 40 which converts the output of the power supply 41 into a pulse voltage in response to the _P1 signal of the timing circuit means 3. According to this configuration, it is possible to generate a pulse voltage having a constant amplitude V and a constant time width _T0 , and the pulse voltage V
(FIG. 6-e) is connected and applied to one of the electrodes 1a provided in the sensor means ₁ through a lead wire 1f1. Next, a current detection means 5 connected to the other electrode 1a by a lead wire _1f2 detects that the engine oil interposed between the electrodes 1a of the sensor means 1 detects the pulse voltage output from the power supply means 4. It consists of a current detection circuit 50 and an LPF circuit 51 to detect the transient response current flowing between the electrodes 1a due to the transient response caused by the applied current. According to this configuration, it is possible to convert the high impedance transient response current of the engine oil between the electrodes 1a into a low impedance voltage signal, and to remove noise such as power supply hum contained in the transient response current. , an accurate transient response current i (FIG. 6.f) can be detected. Next, upon receiving the signals from the current detection means 5 and the timing circuit means 3, the processing circuit means 6 operates the timing circuit 3 to process the transient response current.
The first gate circuit 60 is operated by the output P ₂ signal of 0, and _{the current signal i 1 (} first Figure 6-g) current peak value
A peak detection circuit 61 for measuring ip, the output ip of the peak detection circuit 61 (Fig. 6-h), and the current signal _i1 are input, and the current change amount _Δi (the 6-i), a differential arithmetic circuit 62, a hold circuit 63 that holds the maximum value Δip (FIG. 6-j) of the output Δi of the differential arithmetic circuit 62, and a A second circuit that passes the output ip and the output Δip of the hold circuit 63 during a period when a pulse signal P ₃ (FIG. 6-C) having a fixed time width T ₃ outputted from the reset circuit is applied. gate circuit 64, the gate circuit 64
The ratio △ip/ of the signal _ip1 (Fig. 6-k) corresponding to the current peak value ip output from
The division circuit 6 is used to calculate ip (Fig. 6-l).
It consists of 5. In such a configuration, the first gate circuit 6
The effects of 0 will be explained. Let T ₀ be the time width of the pulse voltage output from the power source means 4, and V be the voltage value thereof. When the pulse voltage (Fig. 6-e) is applied to the electrode of the sensor means 1 facing the engine oil, the engine oil between the electrodes produces a transient response current i as shown in Fig. 6-f.
flows. The initial value of the current i is expressed as i=V/γ ₀ , assuming that the internal resistance of the engine oil is γ ₀ , but this value is because the engine oil between the electrodes has not yet been sufficiently charged. It does not depend on all the conductive substances mixed into the engine oil.
However, after applying a pulse voltage, T ₁ after an arbitrary time elapses.
Since the current ip is a stable value when the conductive substance between the electrodes is sufficiently charged, it depends on the conductive substance mixed in the engine oil. Therefore, in the peak detection circuit 61 in the processing circuit means 6 of this embodiment, after applying a pulse voltage with a constant time width T ₀ to the electrode 1a, the gate circuit 60 detects the transient response current of T ₁ after a certain period of time has elapsed. It has a function to detect the peak value ip of (Fig. 6-g). The transient response current ip detected by the peak value detection circuit 61 is input to one input terminal of the differential calculation circuit 62, and the transient response current after the elapse of the predetermined time _T1 is input to the other input terminal. , by performing differential calculation, it is possible to easily detect the amount of change Δi (FIG. 6-i) in the transient response current within a certain period of time _T2 . In the above configuration, the current peak value at an arbitrary position of the transient response current changes depending on the conductive substance of the engine oil, and the current within the certain period of time changes depending on the change of the conductive substance of the lubricating oil. Calculating the ratio with the amount of change is as follows:
These synergistic characteristics can be grasped, making it an extremely effective measurement value that indicates the state of deterioration of engine oil. A signal ip ₁ corresponding to the current peak value at any position of the transient response current of the engine oil measured by the processing circuit means 6 comprising the above actions and operations and the amount of current change Δi within a certain time.
and the current peak value.
i is input to the next stage determination circuit means 7. The determination circuit means 7 includes a reference value circuit 7 that sets different determination reference values depending on the type of engine oil.
0, a first determination circuit 71 that compares the current peak value signal ip ₁ with a reference value and determines the ratio value signal;
A second determination circuit 72 that compares ip/Δi with a reference value and determines it, and a determination circuit 73 that receives the outputs of the first and second determination circuits and determines the display of the deterioration state of the engine oil. Become. In such a configuration, the reference value circuit 70 determines the initial performance value of the engine oil to be used depending on the type of engine oil (for example, for gasoline engines, diesel engines, etc.) and its properties (for example, different viscosity and additives). By making it possible to select and set arbitrarily, it is possible to accurately determine the state of deterioration of engine oil during its use, and even if a different oil is used when changing the engine oil.
The standard value of the oil can be freely set, and its range of use is extremely wide. Furthermore, the first determination circuit 71 determines the current peak value.
The second judgment circuit 72 determines the degree of deterioration of the oil due to the contamination of conductive substances such as metal powder and sludge contained in the engine oil from the magnitude of ip, and the second determination circuit 72 determines the degree of deterioration of the oil due to the contamination of conductive substances such as metal powder and sludge contained in the engine oil. The deterioration state of the oil is determined based on the correlation with the dielectric substance contained in the conductive substance, insoluble matter, moisture, etc. Further, the determination circuit 73 has a function of determining priority and selection according to the outputs of the first and second determination circuits, and determines the deterioration state of the oil, for example, deterioration due to an increase in conductive substances in the oil, Deterioration due to an increase in dielectric material or deterioration due to a correlation between the two can be determined. Next, in order to accurately display the deterioration state of the oil to the driver according to the output of the determination circuit means 7, the display means 8 displays a display section 81 such as a lamp or a buzzer, and when the deterioration determination result is NG, the oil deterioration state is displayed accurately to the driver. NG until you replace
It consists of a back-clap mechanism 81 to hold the display. In the alarm device having the above configuration and effects, the power source 41 in the power source means 4 inputs a primary voltage signal generated from a battery mounted on a car or the like or an ignition device in the case of a gasoline engine, and inputs the primary voltage signal to an inverter. Therefore, it may be converted to a DC voltage. Furthermore, when the amplitude value of the pulse voltage is about 50 to 300 V, when the electrode gap between the electrodes 1a in the sensor means 1 is about 1 m/m, the deterioration state of the engine oil can be accurately determined. Furthermore, the amplitude value of the pulse voltage of the power source means 4 can be varied as appropriate depending on the properties and type of engine oil to be measured, and can be adjusted to the maximum sensitivity depending on the properties and type of engine oil. Further, it is preferable that the pulse voltage outputted from the power supply means 4 be a single pulse voltage or an intermittent pulse voltage at regular intervals. That is, when a pulse voltage is applied to the electrode 1a, the engine oil interposed between the electrodes is charged due to a transient response, and the electric charge caused by this charging is temporarily charged to the oil. Therefore, if the pulse voltage is continuously applied at intervals such that this charge does not completely disappear from the engine oil, the transient response characteristics will be affected by the influence of this charge, making accurate measurement difficult. Therefore, in the measurement principle of the present invention, a single pulse voltage is applied to the electrode 1a, or an intermittent pulse voltage is applied at appropriate time intervals until the electric charge charged to the engine oil at the time of the initial measurement is completely eliminated. It is desirable to use a pulsed voltage. Furthermore, a division circuit 65 in the processing circuit means 6
In this embodiment, is calculated using the current peak value ip as the denominator and the current change amount Δi as the numerator, but it is also possible to calculate either as the denominator or the numerator. Furthermore, the display means 8 not only displays the performance value or usage limit of the engine oil to be measured at the time of measurement, but also displays the performance value or usage limit of the engine oil to be measured at the time of measurement, if the property or type of the engine oil to be measured is known. The initial performance value is sent to the reference value circuit 7.
By holding the value at 0 and comparing it with the initial performance value, it is also possible to predict and display the remaining life of the engine oil to be measured, that is, the remaining mileage. An example of the results of applying the alarm device according to this example to engine oil in an actual automobile is shown in the seventh section.
As shown in the figure. From Fig. 7, the ratio ip/△i of the current peak value ip of the oil transient response current at any position and the amount of current change △i within a certain period of time increases in proportion to the distance traveled by the car. I understand.
From this fact, the reference value of the reference value circuit 70 in the judgment circuit means 7 is determined as follows: in the ratio value of ip/△i, 6 or less is OK, 6 to 14 is CHECK, and 14 or more is NG.
If it is determined that it is CHECK, it can be determined that it is almost time to change the oil, and if it is NG, it can be determined that oil replacement is necessary. Furthermore, if the initial performance value of the engine oil in Fig. 7 is set to 2 (for example, ip/△i is the performance value), if ip/△p at the time of measurement is an index of approximately 3, it will be 2000~ from the time of measurement. It can be determined that the lubricating oil can be used continuously for up to about 3000km, making it possible to predict the lifespan of the lubricating oil. This fact greatly helps in saving lubricating oil resources and can make a significant social contribution. Next, an example of a method for determining the deterioration state of engine oil in the determination circuit means 7 will be explained using a table. The first determination circuit 7 in the determination circuit means 7
1. The second determination circuit 72 determines that both are OK;
Judgment will be made in three stages: CHECK and NG. For example, as the determination reference value of the current peak value ip in the first determination circuit 71, the relative value is 1 or less.
OK, 1 to 1.5 is CHECK, 1.5 or more is NG, and the second judgment circuit 72 determines ip/△i as in FIG. 7 above.
Relative value of 6 or less is OK, 6 to 14 is CHECK, 14
The above will be judged as NG.

[Table] Based on Table 2, the black circles indicate the selection discrimination circuit 73.
For example, if ip/△i is
If it is OK, the oil is OK even if only ip is judged as CHECK. Even if ip/△i is OK, if ip is NG, there are conductive components such as metal powder and residual carbon in the oil. In this case, CHECK is displayed. (This condition occurs when a car is shipped and has been in use for a short period of time, and can be particularly useful when a large amount of residual metal powder from the car manufacturing process or metal powder from initial wear of mechanical parts is mixed into the oil.) ) In addition, the NG judgment for ip/△i is given priority. The function of the above discrimination circuit 73 is that of AND circuit and OR circuit.
This can be achieved extremely easily using logical circuit means such as circuits, and the output of the discrimination circuit 73 is displayed on a blue lamp when OK, a yellow lamp when CHECK, and a red lamp when NG, etc., to alert the driver. can.
Furthermore, although an embodiment has been shown in which the sensor means 1 is installed in the oil pan of the engine, it may be installed at any position within the oil pan as long as the engine oil is exposed to the sensor means 1. Furthermore, by arranging this sensor means in a pipe such as the outlet of an engine oil cleaner, it becomes possible to prevent sludge and the like contained in the engine oil from entering the electrode 1a of the sensor means 1. Furthermore, if the electrodes 1a of the sensor means 1 are arranged perpendicularly to the level of the engine oil, foreign matter in the oil can be prevented from accumulating between the electrodes 1a. Furthermore, by covering the entire electrode 1a of the sensor means 1 with a mesh or the like, it is possible to prevent sludge or the like in the oil from entering between the electrodes. Further, a temperature sensor 16 disposed in the sensor means 1
Alternatively, the output of a water temperature sensor mounted on the automobile engine may be used instead. Furthermore, the engine oil deterioration warning device of the present invention can be applied not only to engine oil but also to transmission oil and the like. Moreover, a computer used in an engine control system or the like may be used instead of a part of the circuitry in the warning device and the determination method.

[Brief explanation of the drawing]

Figures 1a and 1b are diagrams showing the principle of the present invention, Figures 2a to 2c are photographs showing measurement results according to the present invention as oscilloscope waveforms, and Figure 3 is an embodiment of the present invention. Diagrams showing examples, Figures 4a and 4b
5 is a side view and longitudinal cross-sectional view showing the sensor means, FIG. 5 is a line diagram showing specific details of the above embodiment, and FIG.
Figures a through 6l and 7 are diagrams showing measurement results of specific examples of the present invention, respectively. 1...Sensor means, 2...Temperature detection means, 3...
...timing circuit means, 4...power supply means, 5...
Current detection means, 6... Processing circuit means, 7... Judgment circuit means, 8... Display means.

Claims (1)

[Scope of Claims] 1. Sensor means comprising at least a pair of electrodes facing the engine oil to be measured and a temperature sensor for detecting the temperature of the engine oil; temperature detecting means for determining whether the temperature is within the range; and energizing by an output signal of the temperature detecting means and a signal indicating operation of an engine starting switch, and generating a measurement signal to measure the state of deterioration of the engine oil. timing circuit means for generating a pulse voltage; and power supply means energized by the output of the timing circuit means for generating a pulse voltage of a constant amplitude and a constant time duration in order to apply a pulse voltage to an electrode portion of the sensor means; current detection means for detecting a transient response current of engine oil interposed between the electrodes generated by applying a pulse voltage from the power supply means to the electrodes of the sensor means; and a current at an arbitrary position of the transient response current. Detects the peak value and amount of current change within a certain period of time,
processing circuit means for measuring a ratio value between the current peak value and the current change amount; and comparing and determining the current peak value and the ratio value output from the processing circuit means with a determination reference value to determine the deterioration state of the engine oil. An engine oil deterioration warning device comprising: a determination circuit means for outputting a determination result according to the determination circuit means; and a display means for displaying the deterioration state of the engine oil according to the output of the determination circuit means.