JP2707695B2 - Operating state detection device for variable displacement compressor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a variable displacement compressor suitable for use in, for example, a cooling device of an air conditioner for a vehicle, and more particularly to a state of capacity of the compressor. The present invention relates to an operation state detection device for detecting various operation states such as the above.

(Prior art) Conventionally, in this type of operating state detecting device,
As shown in Japanese Patent Application Laid-Open No. 62-218670, an object to be detected is attached to a part of the outer periphery of a swash plate of a variable displacement swash plate type compressor, and an electromagnetic induction type detector is attached to a part of a peripheral wall of a crank chamber of the compressor. And the detection end of the detector is made to face the crank chamber so as to be able to face the detection object, and the displacement of the detection object accompanying the swing of the swash plate is detected by the detector. In some cases, the operation state of the compressor is detected by electromagnetic induction.

(Problems to be Solved by the Invention) However, in such a configuration, the object to be detected must be attached to the outer periphery of the swash plate as described above.
Further, since the positioning of the detector with respect to the object to be detected must be performed with high accuracy, the cost increases and the reliability of the detection accuracy decreases.

Therefore, in order to cope with such a problem, the present invention is to provide an operating state detecting device which detects the operating state of the variable displacement compressor by effectively utilizing the pressure detecting means. is there.

(Means for Solving the Problems) In solving the above problems, according to the present invention, discharge from a variable displacement compressor interposed in a fluid system in which a fluid circulates and compresses the fluid as a compressed fluid in accordance with the capacity. Pressure detection means for detecting the pressure of the compressed fluid, and the capacity of the compressor is determined based on the fluctuation width of the detected pressure of the pressure detection means, and the rotational speed of the compressor is determined based on the fluctuation number of the detected pressure. Operating state detecting means for detecting the determined capacity and the number of revolutions as the operating state of the compressor.

(Effects) In a state where the compressor compresses the circulating fluid of the fluid system according to the capacity and discharges the compressed fluid as the compressed fluid, the pressure width of the compressed fluid changes due to the change in the capacity of the compressor. , And the number of changes in the pressure of the compressed fluid changes in accordance with the change in the rotation speed of the compressor.

Accordingly, if the pressure of the compressed fluid is detected by the pressure detecting means, the width of the pressure detected by the pressure detecting means fluctuates similarly following the fluctuation width of the pressure of the compressed fluid, and the fluctuation of the detected pressure The number varies according to the temporal variation of the pressure of the compressed fluid.

Therefore, the operating state detecting means obtains the capacity of the compressor based on the fluctuation width of the detected pressure and also obtains the rotational speed of the compressor based on the number of fluctuations of the detected pressure, and compresses the capacity and the rotational speed. If it is detected as the operating state of the machine, this kind of operating state detecting device can be provided as a highly reliable and accurate device.

Further, since the pressure of the compressed fluid may be detected by the pressure detecting means, this kind of operating state detecting device can be provided with a simple configuration at a low cost.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show an example in which the present invention is applied to a variable displacement type swash plate type compressor 10, and FIG. Reference numeral 10 is connected between the evaporator and the condenser in the refrigeration system of the vehicle air conditioner. The compressor 10 is driven by an engine of the vehicle on an input shaft 10a and operates.
The compressor 10 sucks the refrigerant from the evaporator into the suction chamber 15 in accordance with the sliding of the piston 14 in each cylinder 13 accompanying the swinging of the swash plate 12 in the crank chamber 11 in the axial direction,
The suction refrigerant is compressed in the cylinder 13 and sent to the discharge chamber 16 as compressed refrigerant under pressure, and the compressed refrigerant is discharged from the discharge chamber 16 into the condenser. However, in this embodiment, the compressor
As 10, a 6-cylinder type is adopted. Therefore,
Since the pressure of the compressed refrigerant in the discharge chamber 16 fluctuates in an alternating wave shape each time the piston 14 in each cylinder 13 reciprocates,
The fluctuation waveform of the pressure of the compressed refrigerant corresponding to one rotation of the compressor 10 is specified by six AC types resulting from the reciprocating sliding of the six pistons 14 to 14. Further, the amplitude of the pressure of the compressed refrigerant is substantially proportional to the capacity of the compressor 10.

Next, the configuration of the main part of the present invention will be described. The pressure detector 20 is of a semiconductor type, and the pressure detector 20 discharges by discharging its detection end 20a to the rear wall of the discharge chamber 16. Room 1
6 so that it is mounted on the rear wall portion. The pressure detector 20 introduces the compressed refrigerant in the discharge chamber 16 into the detection end 20a, and detects the pressure of the introduced compressed refrigerant by the detection element 21 (see FIG. 2) in cooperation with the oscillator 22 and the switching circuit 23. And the detected refrigerant pressure is generated as a pulsation voltage Vp via the filter 24 and the buffer 25. In such a case, the pulsation voltage Vp is proportional to the pressure of the introduced compressed refrigerant in the detection end 20a.

The DC cut-off capacitor 30 removes a DC component from the pulsating voltage Vp from the pressure detector 20 and removes the remaining component from the pulsating voltage Vp.
Occurs as The amplifier 40 amplifies the filter voltage Vc from the DC blocking capacitor 30 and generates the amplified voltage as an amplified voltage Vca. The waveform shaper 50 shapes the waveform of the amplified voltage Vca from the amplifier 40 and generates it as a shaped voltage Vr. The monostable circuit 60 generates a pulse voltage Vn at every rise of the shaping voltage Vr from the waveform shaper 50.
Are sequentially generated. The AC / DC converter 70 converts the amplified voltage Vca from the amplifier 40 into a DC voltage Vd proportional thereto. Amplifier 8
0 amplifies the DC voltage Vd from the AC / DC converter 70 and amplifies the amplified voltage Vda
Occurs as

The calculation circuit 90 calculates the effective value of the pulsation voltage Vp in response to the pulsation voltage Vp from the pressure detector 20, and calculates the calculation result as
It is generated as a pressure signal representing the pressure of the compressed refrigerant in the discharge chamber 16. Further, the arithmetic circuit 90 determines the number of revolutions N of the compressor 10 according to the number or cycle of each pulse compression Vn from the monostable circuit 60.
Is calculated, and the calculation result is generated as a rotation speed signal. Further, the arithmetic circuit 90 calculates the amplified voltage Vda from the amplifier 80.
, The capacity C of the compressor 10 proportional to the amplified voltage Vda is calculated and generated as a capacity signal. In such a case, the level of the same capacitance signal is proportional to the amplitude of the amplified voltage Vda from the amplifier 80, that is, the amplitude of the amplified voltage Vda from the amplifier 40. In FIG. 2, reference numeral 26 denotes a calibration circuit.

In the present embodiment configured as described above, if the compressor 10 is driven by the engine, the compressor 10 responds to the reciprocating sliding of the piston 14 in each cylinder 13 due to the swing of the swash plate 12,
After sucking the refrigerant from the evaporator into the suction chamber 15, the suction refrigerant is compressed in the cylinder, and is compressed into the discharge chamber 16 as compressed refrigerant.
And then discharged into the condenser.

In such a state, the pressure of the compressed refrigerant in the discharge chamber 16 fluctuates in an AC waveform in accordance with the reciprocating sliding of each piston 14, but such a fluctuating pressure is detected by the pressure detector 20. It is generated as a pulsating voltage Vp. Then
This pulsating voltage Vp is generated as a filter voltage Vc by the DC cutoff capacitor 30 and then amplified by the amplifier 40.
Amplified as Vca. Next, the amplified voltage Vca is waveform-shaped by the waveform shaper 50 as the shaping voltage Vr, and the shaped voltage Vr is sequentially generated as the pulse voltage Vn by the monostable circuit 60 at each rising edge. On the other hand, the amplified voltage Vca from the amplifier 40 is converted into a DC voltage Vd by the AC / DC converter 70, and then generated as an amplified voltage Vda by the amplifier 80.

As described above, when the pulsating voltage Vp, each pulse voltage Vda, and the amplified voltage VDA are generated from the pressure detector 20, the monostable circuit 60, and the amplifier 80, respectively, the arithmetic circuit 90 outputs the effective value of the pulsating voltage Vp to the pressure signal. And generates a rotation speed signal based on each pulse voltage Vn and generates a capacitance signal based on the amplified voltage Vda. In such a case, the level of the pressure signal, the level of the rotation speed signal and the level of the displacement signal are respectively the effective value of the pressure of the compressed refrigerant in the discharge chamber 16, the rotation speed of the compressor 10, and the capacity of the compressor 10. Corresponding to This means that the pressure, rotation speed, and capacity of the refrigerant discharged from the compressor 10 can be detected only by mounting the pressure detector 20 in the discharge chamber 16 and adding a simple electric circuit. Moreover, since it is only necessary to mount the pressure detector 20 in the discharge chamber 16 as described above, it is possible to provide a device for detecting the operation state of the compressor 10 with a simple configuration having high accuracy and high reliability. In addition, the compressor 10 is operated only by processing the output signal of the pressure detector 20.
Although a plurality of operating states are detected, there is no need to separately provide a rotation speed sensor, and the above detection results can be effectively used as information necessary for air conditioning control thereafter.
In particular, the above-mentioned rotation speed signal is useful for detecting the lock of the compressor 10 effectively. Further, the above-mentioned pressure signal is useful for detecting a shortage of refrigerant in the refrigeration system.

Incidentally, when the compressor 10 was driven at 60 (msec) per rotation, the pressure of the compressed refrigerant was confirmed by an experiment using the capacity of the compressor 10 as a parameter, and the result shown in FIG. 3 was obtained. Was. According to this, the amplitude (0.02 kg / cm ² ) of the pressure of the compressed refrigerant at the time of 20% capacity is specified by the AC waveform A in relation to the rotation speed of the compressor 10, and at the time of 100% capacity. It can be seen that the amplitude (0.20 kg / cm ² ) of the pressure of the compressed refrigerant is specified by the AC waveform B in relation to the rotation speed of the compressor 10, and the above-described pressure signal, rotation speed signal, and capacity signal are both AC signals. It was confirmed by the experiments that the various quantities based on the waveforms A and B corresponded accurately. Also,
It was also confirmed that the pressure of the compressed refrigerant was almost proportional to the capacity of the compressor 10, as shown by the straight line L in FIG.

In implementing the present invention, the pressure detector 20
The mounting position of the pressure detector 20 is not limited to the rear wall portion of the discharge chamber 16 and may be any position on the upstream side of the condenser or the receiver of the refrigeration system.

Further, the present invention is not limited to the swash plate type compressor 10, but may be applied to the detection of the operation state of various types of variable displacement type compressors. The present invention is not limited to the refrigeration system of the vehicle air conditioner, but may be applied to the detection of the operating state of the variable displacement compressor in various types of vehicle refrigeration systems, fluid systems such as ships, and the like. .

[Brief description of the drawings]

FIG. 1 is a partially cutaway view showing a mounting position of a pressure detector with respect to a compressor, FIG. 2 is a view showing a circuit configuration of the pressure detector and its attached circuit configuration, and FIGS. It is data showing the experimental result of the operation state of the machine. Explanation of reference numerals 10: compressor, 20: pressure detector, 30: DC cutoff capacitor, 40, 80: amplifier, 50: waveform shaper, 60: monostable circuit, 70: AC / DC converter, 90: arithmetic circuit.

Claims (1)

(57) [Claims] A pressure detection means for detecting a pressure of the compressed fluid discharged from a variable displacement compressor which is interposed in a fluid system in which the fluid circulates and compresses the fluid as a compressed fluid according to a capacity; The capacity of the compressor is obtained based on the fluctuation range of the detected pressure of the pressure detecting means, and the rotational speed of the compressor is obtained based on the number of fluctuations of the detected pressure, and the capacity and the rotational speed are detected as the operating state of the compressor. Operating state detecting device for a variable displacement compressor, comprising: