JPH1062330A - Deterioration detector of lubricating oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To directly measure the viscosity of lubricating oil in real time and automatically output an alarm for the replacement of oil by calculating the viscosity corresponding to the amplitude of pulsation of the oil in an oil passage. SOLUTION: The relation between the amplitude of pulsation of lubricating oil (maximum flow velocity) and the viscosity of lubricating oil is preliminarily stored in an amplitude-to-viscosity map 24. A flow velocity measuring unit 22 supplies a power so that the needle at the tip of a hot wire probe 21 inserted into the oil passage 5 of the lubricating oil is kept at a constant temperature, and outputs the flow velocity of the lubricating oil corresponding to the supplied power. A peak hold circuit 23 receives this flow velocity, and holds the maximum flow velocity synchronously with, for example, the rotation of a crank pin. A viscosity calculating means 25 calculates the viscosity from the maximum flow velocity in reference to the data stored in the map 24. An alarm means 26 outputs an alarm for the replacing time of lubricating oil when the,viscosity is out of a prescribed allowable range. Thus, the viscosity of lubricating oil can be directly measured in real time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a device for detecting deterioration of lubricating oil, and more particularly to a device for detecting deterioration of lubricating oil such as engine oil in an internal combustion engine.

[0002]

2. Description of the Related Art When the lubricating oil in an internal combustion engine deteriorates and the amount of insolubles such as the amount of carbon particles increases or the oil temperature decreases, the viscosity of the lubricating oil increases and the load on the lubrication target member increases. . Further, if the oil temperature is too high, the viscosity becomes too low, which may not be preferable depending on the lubrication target. Therefore, it is necessary that the viscosity of the lubricating oil be in an appropriate range, and therefore, it is desired to measure the viscosity of the lubricating oil.

As a conventional method for measuring the insoluble content of lubricating oil, there is a method for measuring light reflectance (for example, 1993
(See Japanese Patent Application No. 7-72072, filed on May 29, 2009, entitled "Device for detecting concentration of particles in liquid"). However, in the optical measurement method, only the degree of discoloration of the lubricating oil is measured, and not the viscosity itself of the lubricating oil that causes the oil film breakage.

As a conventional method for directly measuring the viscosity of lubricating oil, there is a method of dropping a fixed amount of lubricating oil from a thin tube and measuring the amount of drop per unit time. However, the viscosity cannot be measured in real time. There is a problem.

[0005]

As described above, in the conventional optical measuring method, only the degree of discoloration of the lubricating oil is measured, and the viscosity itself of the lubricating oil causing the oil film breakage is measured. However, there is a problem that accurate measurement of viscosity is not possible. In addition, since the viscosity cannot be measured in real time by a method such as dropping a droplet of lubricating oil and measuring the amount of drop per unit time, there is a problem that it is not possible to know the timing of replacing the lubricating oil in real time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a device for detecting deterioration of a lubricating oil which can directly measure the viscosity of the lubricating oil in real time in view of the above-mentioned problems in the prior art. Another object of the present invention is to provide a device for detecting deterioration of a lubricating oil which automatically outputs a warning prompting replacement when the viscosity of the lubricating oil becomes a predetermined value or more.

[0007]

According to the present invention, it is possible to calculate the viscosity of the lubricating oil corresponding to the amplitude of the pulsation of the lubricating oil in the lubricating oil passage. Has the effect of being able to measure the viscosity directly and in real time. According to the second aspect, the rotor acts so as to generate the pulsation of the lubricating oil, thereby obtaining an effect that the viscosity can be measured even in the oil path without pulsation.

According to the third aspect of the present invention, the temperature of the lubricating oil acts so as to be kept constant, whereby a map showing the relationship between the amplitude of the pulsation of the lubricating oil and the viscosity of the lubricating oil is obtained for each temperature. The effect that it is not necessary to have it is acquired. According to the fourth aspect, when the calculated viscosity is out of the predetermined allowable range, an operation is performed so as to output an alarm, thereby obtaining an effect that it is possible to know the timing of replacing the lubricating oil in real time.

According to the fifth aspect, it is possible to change the allowable range of the viscosity in response to the change in the oil temperature, whereby it is possible to more accurately know the timing of replacing the lubricating oil in real time. The effect that it can be obtained is obtained.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. Like reference numerals denote like elements throughout the previous figures. FIG. 1 is a sectional view showing a part of an internal combustion engine to which an embodiment of the present invention is applied. In the figure, 1 is a cylinder block, 2 is a crank pin, 3 is a crankshaft oil hole, 4 is an oil passage leading to a connecting rod, 5 is an oil passage on the cylinder block side, and 6 is a connecting rod.

The lubricating oil of the internal combustion engine pulsates in accordance with the cycle of pressurization by the oil pump, and when the crankpin 2 rotates, the oil flows between the crankshaft oil hole 4 and the oil passage 5 on the cylinder block side. In addition, a lot of lubricating oil flows in the oil passage 5, thereby causing pulsation in the lubricating oil in the oil passage 5, and pulsation occurs everywhere. In the embodiment of the present invention, the viscosity of the lubricating oil is measured by measuring the amplitude in the pulsation.

The measuring principle is as follows. That is, as the viscosity of the lubricating oil increases, the ability to follow the flow velocity of the lubricating oil decreases, and the maximum speed of the pulsation, that is, the amplitude in the pulsation, decreases. Therefore, the viscosity can be calculated by storing the relationship between the maximum pulsation speed and the viscosity in a map in advance and measuring the maximum speed of the lubricating oil. FIG. 2 is a diagram showing a lubricating oil deterioration detecting device according to an embodiment of the present invention for calculating a viscosity based on the above measurement principle. In the figure, 2
Reference numeral 1 denotes a hot-wire probe, in which a needle made of two ultrafine metal wires is inserted into the oil passage 5. 22 is a flow velocity measuring unit,
Electric power is supplied so that the needle at the tip of the hot wire probe 21 is kept at a constant temperature. The measurement principle is as follows. That is, when the flow velocity is high, the amount of heat taken from the tip of the hot-wire probe 21 increases, so that the supplied power increases to keep the temperature of the distal end of the hot-wire probe 21 constant, and conversely, the supplied power decreases when the flow velocity decreases. . Therefore,
The flow rate corresponding to the power supplied to the hot wire probe 21 is obtained as the output of the flow rate measurement unit 22.

Reference numeral 23 denotes a peak hold circuit, 24 denotes a map of amplitude versus viscosity, 25 denotes viscosity calculating means, and 26 denotes alarm means. FIG. 3 is a graph showing the relationship between the viscosity and the flow rate of the lubricating oil. As shown in the figure, the flow rate of the lubricating oil becomes maximum, for example, every one rotation of the crankpin 2. When the viscosity is low, the pulsation amplitude (maximum flow velocity) of the lubricating oil is large,
As the viscosity increases, the pulsation amplitude (maximum flow velocity) of the lubricating oil decreases. This indicates that there is a certain relationship between the amplitude of the lubrication oil pulsation and the viscosity of the lubrication oil. However,
In this case, it is assumed that the oil temperature of the lubricating oil is a constant temperature cooled by a radiator or the like.

FIG. 4 is a graph showing the relationship between the amplitude of the lubrication oil pulsation and the viscosity of the lubrication oil. As shown, the maximum flow rate of the lubricating oil is substantially inversely proportional to the viscosity of the lubricating oil. The maximum flow velocity of the lubricating oil is equal to the amplitude of the lubricating oil pulsation. The amplitude versus viscosity map 24 shown in FIG.
The relationship between the amplitude of the pulsation of the lubricating oil and the viscosity of the lubricating oil is stored.

Next, the operation of the apparatus for detecting deterioration of lubricating oil shown in FIG. 2 will be described. The flow velocity obtained at the output of the flow velocity measurement unit 22 is input to the peak hold circuit 23, and the maximum velocity is
For example, it is held in synchronization with the rotation of the crank pin 2. The maximum speed is input to the viscosity calculating means 25. The viscosity calculating means 25 refers to the output of the amplitude versus viscosity map 24,
Calculate the viscosity. The calculated viscosity is input to the alarm means 26, and when the viscosity is out of the predetermined allowable range, an alarm is output indicating that it is time to replace. Alerts can be visual,
It may be auditory. When the lubricating oil is an engine oil, for example, the amount of insoluble components such as the amount of carbon particles that increase the viscosity increases, and when the lubricating oil exceeds the permissible viscosity, replacement is urged.

In this manner, the viscosity of the lubricating oil can be directly measured in real time, and the user is automatically notified of the lubricating oil replacement time, so that forgetting to replace the lubricating oil can be prevented. In the above-described embodiment, the case where the pulsation of the lubricating oil has occurred has been described. However, even in the oil passage where the pulsation has not occurred, the viscosity can be measured as in the second embodiment described below. .

FIG. 5 is a view showing an apparatus for detecting deterioration of lubricating oil according to a second embodiment of the present invention. 2 differs from the embodiment of FIG. 2 only in that a rotor 51 is provided in the oil passage 5. The rotor 51 is rotated at a constant rotational speed per unit time by a motor (not shown) or the like, thereby pulsating the lubricating oil. The maximum speed of that pulsation,
The viscosity is calculated by the amplitude-viscosity map 24 while being held in the same manner as in the first embodiment, and an alarm is issued when the viscosity is out of the predetermined allowable range.

In the above embodiment, the temperature of the lubricating oil is constant, but the temperature of the lubricating oil is not always constant. When the oil temperature changes, the relationship between the amplitude and the viscosity also changes. Therefore, when the temperature of the lubricating oil changes, the above embodiment must have a plurality of amplitude-viscosity maps corresponding to the temperature change. FIG. 6 is a diagram showing a device for detecting deterioration of lubricating oil according to a third embodiment of the present invention. In FIG.
The difference from this embodiment is that the allowable range of the viscosity is changed according to the oil temperature by the oil temperature measurement sensor 61, the temperature measurement unit 62, and the viscosity versus oil temperature map 63.

FIG. 7 is a graph showing the relationship between the viscosity of lubricating oil and the oil temperature when impurities such as carbon particles contained in the lubricating oil are constant. As shown, the viscosity decreases exponentially with increasing oil temperature. The relationship between the viscosity and the oil temperature is stored in the map 63. The boundary threshold value of the allowable range indicating the lubricating oil replacement time changes according to the viscosity shown in FIG. That is, the lower the oil temperature, the higher the viscosity, and thus the higher the threshold value. On the other hand, if the oil temperature is high, the viscosity is low, and thus the threshold value is low.

In this manner, by changing the threshold value of the allowable range of the viscosity in accordance with the oil temperature, it is possible to optimally warn of the timing of replacing the lubricating oil.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a part of an internal combustion engine to which an embodiment of the present invention is applied.

FIG. 2 is a diagram showing a device for detecting deterioration of lubricating oil according to one embodiment of the present invention.

FIG. 3 is a graph showing a relationship between a viscosity and a flow rate of a lubricating oil.

FIG. 4 is a graph showing the relationship between the amplitude of lubrication oil pulsation and the viscosity of lubrication oil.

FIG. 5 is a diagram showing a device for detecting deterioration of lubricating oil according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a device for detecting deterioration of lubricating oil according to a third embodiment of the present invention.

FIG. 7 is a graph showing a relationship between viscosity and oil temperature of a lubricating oil when impurities such as carbon particles contained in the lubricating oil are constant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 ... Crankshaft oil hole 5 ... Oil passage 22 ... Flow velocity measuring unit 23 ... Peak hold circuit (pulsation amplitude measuring means) 24 ... Amplitude vs. viscosity map 25 ... Viscosity calculating means 26 ... Alarming means 51 ... Rotator 62 ... Oil temperature measurement Unit 63: viscosity vs. oil temperature map

Claims (5)

[Claims] A pulsation amplitude measuring means for measuring a pulsation amplitude of the lubricating oil in an oil passage of the lubricating oil; and a viscosity calculating means for calculating a viscosity of the lubricating oil corresponding to the measured amplitude. Lubrication oil deterioration detector. 2. The lubrication system according to claim 1, further comprising: a rotor provided in the oil passage, the rotor rotating at a constant rotation speed per unit time, and the rotor pulsating the lubricating oil. Oil deterioration detection device. 3. The device for detecting deterioration of lubricating oil according to claim 1, further comprising means for maintaining a constant temperature of the lubricating oil provided in the front oil passage. 4. The lubricating oil deterioration detection device according to claim 1, further comprising an alarm unit that outputs an alarm when the calculated viscosity is out of a predetermined allowable range. 5. An oil temperature measuring means provided in a front oil passage for measuring a temperature of the lubricating oil, a means for outputting an allowable range of viscosity corresponding to the measured oil temperature, and The lubricating oil deterioration detection device according to claim 1 or 2, further comprising an alarm unit that outputs an alarm when the viscosity is out of an allowable range of the viscosity corresponding to the oil temperature.