JPS61741A - Oil deterioration detector - Google Patents

Abstract

PURPOSE:To enable continuous and quantitative detection of oil deterioration, by forming a microwave resonance hollow while microwave is transmitted to a box body for passage of oil through or holding thereof in to check deterioration in oil from the behavior of a signal received. CONSTITUTION:Both openings of a box body 1 is connected to an oil piping P and provided with a porous plate 2 in which through pores 21 are formed to allow oil to pass freely. The diameter of the through pores 21 shall be large enough to block the passage of microwaves for use in detection and the box body 1 acts as a resonance hollow thereof. A transmitting antenna 3a is provided on the side wall of the box body 1 to transmit microwaves into the box body 1 and a receiving antenna 3b to receive them facing each other while the antenna 3a is connected to a microwave oscillator 4 and the antenna 3b to a microwave detector 5 respectively. The oscillation controlling circuit 6 controls the oscillator 4 so as to oscillate microwaves with a continuously varying frequency repeatedly. A signal processing circuit 7 can detect deterioration in oil from variations in the resonance frequency of the microwave received.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an oil deterioration detection device that detects deterioration of engine oil y and gives an alarm.

[Prior art]

In recent years, the demand for diesel engines has increased from the viewpoint of economic efficiency, but the engine oil used in these engines tends to deteriorate due to carbon contamination, etc., and appropriate oil management is necessary. °Also, even in gasoline engines, the oil supplied to the high-temperature bearings of the turbocharger deteriorates quickly.
Conventionally, oil deterioration has been determined by the color of oil μ adhering to a level gauge, and it has been impossible to continuously and quantitatively detect oil deterioration.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above conventional problems, it is an object of the present invention to provide an oil deterioration detection device that accurately detects leadification of oil μ and issues an alarm.

[Structure of the invention]

The inventors have focused on the fact that the dielectric constant of oil μ increases as it deteriorates, and propose an oil deterioration detection device using microwaves that responds extremely sensitively to changes in the dielectric constant.

That is, the detection device of the present invention includes a housing that forms a microwave resonant cavity and that circulates or holds oil, a microwave transmitting means that transmits microwaves into the housing, and a microwave transmitter that transmits microwaves into the housing. The apparatus includes receiving means for receiving the microwave and emitting a received signal according to the intensity of the received microwave, and signal processing means for detecting oil deterioration in the behavior of the received signal and emitting an oil deterioration signal.

[Embodiment 1] In FIG. 1, a cylindrical casing 1 is disposed in the middle of an oil pipe P, forming a part of an oil flow path. That is, the casing 1 has both openings connected to the expanding ends of the piping P, and a perforated plate 2 having a large number of through holes 21 for allowing oil to freely flow is disposed in both openings. It is. The diameter of the through hole 21 of the perforated plate 2 is set to a size that blocks the passage of microwaves used for detection.
acts as a microwave resonant cavity. The resonant frequency of the housing 1 changes extremely sensitively depending on the dielectric constant of the oil flowing through it.

A transmitting antenna 3a for transmitting microwaves into the housing 1 and a receiving antenna 31:l for receiving microwaves resonated within the housing 1 are provided on the side wall of the housing 1 so as to face each other. The antenna 3a is connected to a microwave oscillator 4, and the antenna 3b is connected to a microwave detector 5. In the figure, 6 is an oscillation control circuit which controls the oscillator 4 to repeatedly oscillate microwaves whose frequency changes continuously.

7 is a signal processing circuit that detects oil deterioration (changes in the resonant frequency of the received microwave) and activates a display circuit 8 connected thereto.

FIG. 2 shows the structure of the oscillator 4. A resonant cavity 42 with one end open to the side is formed in the housing 41 of the oscillator 4. Inside the cavity 42, a mitallo wave oscillation element 43 such as a Gunn diode and a variable capacitance element 44 such as a varactor diode are disposed. It is arranged. Oscillation element 43 is external terminal 43
A microwave is oscillated by a constant bias voltage applied through the antenna 1, and the oscillated microwave passes through a coaxial waveguide converter 45 to a coaxial cable 46 and is transmitted to the transmitting antenna 3.
Sent to a. At this time, by changing the bias voltage applied to the variable capacitance element 44 via the external terminal 441, the frequency of the oscillated microwave can be continuously changed.

FIG. 3 shows the structure of the detector 5. A microwave detection element 53 such as a Schottky barrier diode is disposed within a resonant cavity 52 formed within the housing 51 . The microwave received by the receiving antenna 3b is sent to the coaxial cape A1.
55 and the coaxial waveguide converter 54 to the detection element 53, and the detected received signal 53a is taken out through the external terminal 531.

FIG. 4 shows the configuration of the oscillation control circuit 6. The control circuit 6
are a DC power supply 61, a pulse generation circuit 62, and a sawtooth wave generation circuit 6.
3 and the booster circuit 64, the DC power supply 61 supplies a bias voltage to the oscillation element 43 of the oscillator 4. The pulse generating circuit 62 generates a sweep control signal 62a (FIG. 7 (1), (6)) consisting of a bus train of a predetermined period, and
2a, the sawtooth wave generation circuit 63 generates a sawtooth wave signal 63a ((2), (3) in FIG.
) is output. The signal 63a passes through the booster circuit 64'
The signal is input to the variable capacitance element 44 of the oscillator 4, thereby sweeping the frequency of the oscillated microwave. Note that the frequency of the microwave increases continuously as the voltage of the signal 63a increases.

FIG. 6 shows the configuration of the signal processing circuit 7. In the figure, 71 is a bias current setting resistor, 72 is an amplifier circuit, 73 is a differential circuit, 74 is a comparator, 75 is an inverter, 76 is a clock pulse generation circuit, and 77 is a counting circuit.

The received signal 53a emitted from the external terminal 531 of the detector 5 is amplified by the amplifier circuit 72. The intensity of the received microwave is maximum when its frequency matches the resonant frequency of the housing 1 (Fig. 1). Therefore, the amplified signal '/2a of the received signal 53a is the same as that shown in Fig. 7 (Fig. 1). The amplified signal lea is a repetitive signal having a single peak for each sweep.
The differential signal 73a (Fig. 7 (5)) is differentiated by
A comparison circuit 74 compares it with a constant voltage Va.

Signal 5a in which the comparison output is inverted by the inverter 75
is the amplified signal 'F21' as shown in Figure 7 ('?)K.
The signal is at the Ill level from when a reaches its peak until the end of the sweep cycle. The counting circuit mother is the above signal'
While 15a is at the "l" level, the click pulse emitted by the pulse generator '76 is clicked, and when the count value exceeds a predetermined value, an oil deterioration detection signal a is generated.The counting circuit is controlled by sweep control. Signal 62a (Fig. 7 (1))
It is reset periodically every day, and normally the count value does not exceed the predetermined value.

In the display circuit 8- shown in FIG. 6, the oil deterioration detection signal '? When a is input, the indicator lamp 82 is turned on via the current amplification circuit 81.

Now, as the deterioration of the oil progresses, its dielectric constant increases, and the resonant frequency of the housing 1 gradually shifts to the lower frequency side. That is, the waveform of the signal 72a is as shown in FIG.
) changes as shown by the chain line, and the peak moves from point X to point px. This conclusion.

The intersection of the output signal '73a and the constant voltage Va shifts, and the (7th
Figure (5) chain line), signal'? The time during which the signal a remains at the "1" level becomes longer (as shown by the chain line in FIG. 7), and eventually the count value of the counting circuit 770 exceeds a predetermined value and the oil deterioration detection signal a is generated.

Note that the transmitting antenna 3a and the receiving antenna 3b in the above embodiment can also be used as a transmitting and receiving antenna. This is shown in FIG.

In the figure, the transmitting/receiving antenna 3 is a circulator 9.
It is connected to the oscillator 4 and the detector 5 via. The other configurations are the same as those of the above embodiment. The microwave transmitted from the oscillator 4 passes through the circulator 9 and is transmitted from the antenna 3 into the housing 1, and the microwave resonated within the housing 1 is received again by the antenna 3, passes through the circulator 9, and is sent to the detector. 5. In this case, unlike the above embodiment, the intensity of the received microwave reaches its lowest value at the resonant frequency. Therefore, the inverter 75 in the signal processing circuit 7 (FIG. 5) is unnecessary.

[Embodiment 2] Fig. 9 shows the housing 1 attached to the oil drain hole for the oil pan L.
An example in which it is used in combination with I/) is shown below. That is, the housing 1 is constructed as a stepped shaft having a through hole in the center, and is screwed into an oil drain hole L1 provided on the bottom of the oil pan L by means of a threaded portion 11 formed on the outer periphery of the small diameter portion. be. A transmitting/receiving antenna 3 is liquid-tightly sealed in one opening of the through hole, and the other opening located in the oil is a through hole that allows oil to flow but does not allow microwaves to pass through. It is covered with a perforated plate 2 having many holes. As a result, a microwave resonant cavity filled with oil is formed within the housing 1 serving as the extraction bolt υ. A coaxial cable 32 is connected to the antenna 3 via a coaxial plug 31.

With such a structure, the same effects as those of the above embodiments can be obtained, and furthermore, no particular installation space is required for the casing 1 serving as the detection section, and it is easy to replace or clean the casing 1.

[Embodiment 3] In FIG. 10, a microwave switching element 47 such as a P-type N diode is provided in the resonant cavity 42.

The switching element 417 receives a pulsed switching signal 65a (the first signal) from the pulse generating circuit 65 shown in FIG.
3 (1) is applied, and the switching element 47 chops the microwave emitted by the microwave oscillation element 43 according to the signal 65a. In this embodiment, the frequency of the microwave emitted from the oscillation element 43 is made to match the initial resonance frequency of the housing 1 (FIG. 1) when the oil has not deteriorated.

The received signal 53a emitted by the wave detector 5 (FIG. 1) is amplified by the AC amplifier circuit 75 (FIG. 12), and is compared with the constant voltage vb by the comparator 4 as a signal '15a. The comparison signal 'F4a is input to the counting comparison circuit 78.

When the oil has not deteriorated, the level of the signal 'F5a is sufficiently higher than the constant voltage Vb (Fig. 13 (2)).
As a result, the comparison signal 74a pulsates like a pulse in response to the signal '75a (left half of FIG. 13(3)). On the other hand, as the oil deteriorates, its dielectric constant increases, and the resonant frequency of the housing 1 changes from its initial value. As a result, the level of the signal 75a gradually decreases and finally reaches a constant voltage v
b (Figure 1.3 (right half of Figure 1.3)), comparison signal '?4a is no longer output (Figure 13 (3) right half)
.

At this point, the count comparison circuit 78 issues an oil deterioration detection signal 7a.

The configuration of this embodiment also provides the same effects as those of the above embodiment.

Note that in this embodiment, the oscillated microwave was chopped to use an inexpensive AC amplifier circuit 75 as an amplifier circuit, but if a DC amplifier circuit is used, there is no need to chop the microwave.

〔Effect of the invention〕

As described above, the oil deterioration detection device of the present invention allows oil to flow into the housing forming the microwave resonant cavity.
This system detects oil deterioration based on the behavior of microwaves that sensitively changes as the oil μ deteriorates, making it possible to detect oil deterioration continuously and quantitatively.

[Brief explanation of drawings]

Figure 1 is a diagram showing the overall configuration of the device including a cross-sectional view of the detection section installed in the oil pipe, Figure 2 is a schematic overall cross-sectional view of the microwave oscillator, and Figure 3 is a schematic overall cross-sectional view of the microwave detector. Figure 4 is a block diagram of the oscillation control circuit, Figure 5 is a circuit diagram of the signal processing circuit, Figure 6 is a circuit diagram of the display circuit, and Figure 7 is a block diagram of the oscillation control circuit.
The figure is a time chart of various signals, FIG. 8 is a diagram showing the main part of an embodiment using a transmitting and receiving antenna, FIG. 9 is a sectional view of a detection section showing a second embodiment of the present invention, and FIG. 10 to 13 show a third embodiment of the present invention, FIG. 10 is a schematic overall sectional view of a microwave oscillator, FIG. 11 is a block diagram of an oscillation control circuit, and FIG. 12 is a circuit of a signal processing circuit. 13 are time charts of various signals. 1...Housing 3.3a, 3b...Antenna 4...Microwave oscillator (microwave transmission means) 5...Microwave detector (microwave transmitting means) wave receiving means) 6...Oscillation control circuit 7...Signal processing circuit (signal processing means) 8...
...Display circuit Fig. 5 Fig. 6 Fig. 7 Fig. 8-3 ~ Fig. 9 Fig. 1o Fig. 11 Fig. 12

Claims (3)

[Claims] (1) A housing that forms a microwave resonant cavity and that circulates or holds oil, a microwave transmitter that transmits microwaves into the housing, and a microwave transmitter that receives the microwaves transmitted into the housing. An oil deterioration detection device comprising: a receiving means for emitting a received signal according to the intensity of a received microwave; and a signal processing means for detecting oil deterioration from the behavior of the received signal and emitting an oil deterioration signal. (2) The microwave transmitting means is set to repeatedly transmit into the housing a microwave whose frequency continuously changes within a range including the resonant frequency of the housing, and the signal processing means 2. The oil deterioration detection device according to claim 1, wherein the oil deterioration detection device is set to emit an oil deterioration signal when the frequency of the microwave at which the level of the received signal reaches a peak changes beyond a predetermined value. (3) The microwave transmitting means is set to transmit microwaves into the housing at a resonant frequency of the housing, and the signal processing means is configured to transmit the microwave to the housing when the level of the received signal changes beyond a predetermined value. The oil deterioration detection device according to claim 1, wherein the oil deterioration detection device is configured to emit a deterioration signal.