JPS62125263A - Compressor for air-conditioning - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an air conditioning compressor that compresses fluid circulating in a refrigeration cycle.

(Prior Art) As such an air conditioning compressor, there is a conventional compressor as shown in FIG. 6, for example. This air conditioning compressor 1 constitutes a refrigeration cycle together with an evaporator and a condenser, and sucks refrigerant gas (circulating through the refrigeration cycle) into pump chambers (compression chambers) 4 and 5 from suction ports 2 and 3. The refrigerant gas sucked into the pump chambers 4 and 5 is compressed by a plurality of vanes 8 supported so as to project freely through a plurality of slits 7 of a rotor 6 rotating in the direction of the arrow, and then discharged from discharge ports 9 and 10 through a discharge valve. 11 and 12 are pushed open to be discharged and sent to the downstream side of the refrigeration cycle.

(Problems to be Solved by the Invention) However, in such conventional air conditioning compressors, the discharge capacity is constant (even if one of the suction ports 2 and 3 is closed to reduce the capacity to 1/2, the discharge capacity remains 1/2). Since the discharge capacity cannot be changed continuously, the lower first set temperature (evaporator antifreeze temperature) with a predetermined temperature difference is set at 1+ and the higher one with a predetermined temperature difference. Set the second set temperature t2, and when the temperature of the evaporator or the air discharged from it decreases and reaches the first set temperature 1° as shown in Figure 7 (al), Turn off the electromagnetic clutch to stop the operation of the air conditioning compressor 1 as shown,
When the temperature rose again and reached the second set temperature t2, the electromagnetic clutch was turned on to operate the air conditioning compressor again. If only one set temperature is set at t+, the electromagnetic clutch of the air conditioning compressor 1 will repeatedly turn ON and OFF violently in a very short period of time, resulting in so-called hunting, so to prevent this, a certain temperature difference is set. A second set temperature t2 is set. For this reason, even if hunting can be prevented, the electromagnetic clutch of the air conditioning compressor 1 repeats 0N-OFF at a predetermined interval with a longer period than hunting, which generates noise or impact each time, making the occupants feel uncomfortable. There was a problem.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention constitutes a refrigeration cycle together with an evaporator, and compresses the fluid that circulates through the refrigeration cycle, sucked in through the suction port, in a compression chamber and discharged. In an air conditioning compressor, a temperature detection means detects the temperature of the evaporator or the temperature of the air blown out from the evaporator, and a difference between the temperature detected by the temperature detection means and a preset target value is compared and calculated. a temperature difference calculation means, a thermal change rate calculation means for calculating a thermal change rate with respect to time of the evaporator or air blown out from the evaporator, and controlling the inlet to close at a predetermined rate per arbitrary unit time. suction port closing control means, wherein the suction port closing control means closes the suction port based on the temperature difference calculated by the temperature difference calculation means and the thermal change rate calculated by the thermal change rate calculation means. The temperature is maintained near the target value by changing the ratio.

(Function) According to such an air conditioning compressor, the difference between the temperature of the evaporator detected by the temperature detection means or the temperature of the air blown out from the evaporator and a preset target value, and
Based on the rate of change of these temperatures over time, the discharge capacity of the air conditioning compressor is continuously changed by changing the predetermined rate at which the inlet is closed per unit time, and the temperature is kept close to the target value. can be retained.

Therefore, the electromagnetic clutch of the air conditioning compressor can be avoided from repeatedly turning ON and OFF as in the past.
It is possible to prevent the occupants from being uncomfortable and confused due to noise or impact caused by turning the switch ON/OFF.

(Example) Embodiments of the present invention will be described below based on the drawings.

1 to 4 are diagrams showing an embodiment of an air conditioning compressor according to the present invention.

First, to explain the configuration, in FIG. 1, 21 is an engine, and 22 is a transmission belt 23 that drives the engine 21.
The compressor 24 is an electromagnetic clutch that connects and disconnects the drive from the engine 21 to the compressor 22 . Further, 25 is a condenser that cools and liquefies a refrigerant (fluid circulating in the refrigeration cycle) such as Freon gas, which has been compressed by the compressor 22 and becomes high temperature and high pressure;
Reference numeral 26 denotes an evaporator that evaporates the liquefied refrigerant sent from the condenser 25 and removes heat from the surrounding air to turn it into a gaseous body. The refrigerant gasified by the evaporator 26 is sucked into the compressor 22 again, and this series of refrigeration cycles is repeated to continue removing heat from the air in the vehicle interior and lowering the temperature and humidity. Also, 27 is the evaporator 2
Evaporator 2 installed immediately after the cooling air outlet side of No. 6
This is a temperature detector (temperature detection means) that detects the temperature of the air blown out from 6. In the figure, 28 is a liquid tank that separates the refrigerant liquefied by the condenser 25 into gas and liquid, 29 is an expansion valve, and 30 is an electric fan that sends air inside the vehicle to the evaporator 26.

32 is a control unit, and the control unit 32 compares a signal corresponding to the detected temperature from the temperature sensor 27 with a pre-stored target value and calculates the difference (temperature difference calculation means), and also performs temperature detection. Thermal change rate calculation means (thermal change rate calculation means) picks up the signal from the device 27 at predetermined time intervals in synchronization with the clock and calculates the rate of change of the ever-changing temperature (thermal change rate calculation means), based on these temperature differences and the rate of thermal change. A predetermined rate at which the suction boat is closed per arbitrary unit time is changed by controlling an on-off valve 33 for opening and closing the suction port, which will be described later, provided on the compressor 22 side (suction port closing control means).

Here, the structure of the compressor 22 employed in the embodiment will be schematically explained with reference to FIGS. 2 to 4.

In this compressor 22, a cam ring 40 having a substantially elliptical cam surface 40a is sealed with front and rear plates 41 and 42 from both sides in the axial direction, and a rotor 43 is rotatably housed inside the cam ring 40. A vane 45 is fitted into a radial slit 44 formed in the rotor 43 so as to be freely retractable. A back pressure passage 46 is formed at the bottom of each slit 44 , and each back pressure passage 46 communicates with a communication hole 47 formed in the rotor 43 . Lubricating oil is supplied. Adjacent vanes 45 are located in the space between the cam ring 40 and the rotor 43.
A pump chamber 48 is defined by this. A refrigerant such as Freon gas is sucked into this pump chamber 48 from two suction ports P1 and Pt (suction ports), and is caused by the centrifugal force accompanying the rotation of the rotor 43 and the pressure of lubricating oil in the back pressure passage 46 (vane back pressure). The vane 45 rotates in sliding contact with the cam surface 40a. As a result, the refrigerant is compressed and the corresponding discharge port 1-3
1, it will be discharged from S2. Suction boat P,
, P, are arranged at equal intervals in the circumferential direction of the cam ring 40 (
180° apart). Further, for example, as shown in FIGS. 3 and 4, one suction boat P2 is equipped with an on-off valve 33 such as a solenoid valve, and a control signal from the control unit 32 shown in FIG. Valve 3
3, the direction to close the suction boat pz (the third
(see figure). The on-off valve 33 may be provided on the suction boat PI (or may be provided on both the suction boats P and P2).

Next, the effect will be explained. The drive of the engine 21 is transmitted to the compressor 22 when the electromagnetic clutch 24 is turned on, and cooling starts. The refrigerant compressed by the compressor 22 is cooled and liquefied by the condenser 25, and then vaporized by the evaporator 26, which removes heat from the air inside the vehicle to cool the interior of the vehicle. The temperature detector 27 detects the temperature of the air blown out from the evaporator 26 and outputs a temperature signal to the control unit 32.

Control unit 3 inputting temperature signal from temperature sensor 27
2, the temperature difference calculation means first compares it with a pre-stored target value t2 and calculates the difference d.
This target value t2 is set slightly higher than the anti-freezing temperature t1 of the evaporator 26, as shown in FIG. 5(a). Next, the control unit 32 uses its thermal change rate calculation means to synchronize the signal from the temperature detector 27 with the clock, perform big amplification at predetermined time intervals, and calculate the rate of change υ of the ever-changing air temperature. . Furthermore, the control unit 32 uses its suction port closing control means to determine the duty from a data map as shown in FIG. A ratio is selected and a signal corresponding to the duty ratio is output to the on-off valve 33. As a result, the on-off valve 33 is connected to the suction boat P and/or
It is controlled to close Pz at the most appropriate rate per unit time. In this way, as shown in Figure 5 (bl), when the difference d between the target value t2 and the air temperature is large and the temperature change rate υ is small, the duty ratio is large; When the difference d is small and the temperature change rate υ is large, the on-off valve 33 is controlled with a small duty ratio, and in other cases, as shown in the data map, the on-off valve 33 is controlled with an intermediate duty ratio according to the respective conditions. Therefore, by continuously changing the discharge capacity of the compressor 22, the temperature of the air blown out from the evaporator 26 is maintained in the vicinity of the target value t2 most efficiently as shown in FIG. Therefore, the electromagnetic clutch of the air conditioning compressor can be avoided from repeatedly turning ON and OFF in a complicated manner as in the past, and the noise or impact caused by the ON and OFF operations can cause discomfort to the occupants. Furthermore, the above control can also prevent the air temperature from dropping to the freezing prevention temperature 1.

In the above embodiment, the temperature sensor 27 is provided immediately after the cooling air outlet side of the evaporator 26 to detect the temperature of the cooling air.
may be provided in the evaporator 26 itself to detect the temperature of the evaporator 26 itself. Further, in the above embodiment, the thermal change rate with respect to time of the air blown out from the evaporator 26 was replaced with the temperature change rate, but the thermal change rate is not limited to the temperature change rate. Enthalpy may be calculated by detecting various elements such as the amount of air, temperature, humidity, and heat mass, and the rate of change of the enthalpy over time may be used as the rate of thermal change.

(Effects of the Invention) As explained above, according to the air conditioning compressor of the present invention, the temperature of the evaporator or the air blown out from it can be maintained near the target value. It is possible to prevent the electromagnetic clutch of the compressor from repeatedly turning ON and OFF at predetermined intervals, and it is possible to effectively prevent the occupant from being uncomfortable and confused due to noise or impact caused by the ON-OFF operation. It is also possible to prevent the temperature of the evaporator and the air blown out from it from dropping to the anti-freezing temperature.

[Brief explanation of drawings]

Figures 1 to 5 are diagrams showing one embodiment of the air conditioning compressor according to the present invention. Figure 1 is an overall view of a refrigeration cycle including the air conditioning compressor, and Figure 2 is a diagram of the air conditioning compressor. 3 is a sectional view taken along the line m-■ in FIG. 2, and FIG. 4 is a suction bow shown in FIG. On-off valve 33 showing the state
A partial sectional view of the vicinity, FIG. 5 (Al is a diagram showing the relationship with time showing changes in air temperature, FIG. 5 (BL is a diagram showing an example of a data map of the duty ratio stored in the control unit 32, and FIG. 6 The figure is a cross-sectional view of a conventional air conditioning compressor, Figure 7 [a]
7(b) is a time chart showing temperature changes in the conventional air conditioning compressor, and FIG. 7(b) is a time chart showing ON/OFF changes of the electromagnetic clutch of the air conditioning compressor. 21... Engine, 22... Compressor, 23... Transmission belt, 24... Electromagnetic clutch, 25... Capacitor, 26. ...Evaporator (evaporator), 27...
...Temperature detector (temperature detection means), 28...
Liquid tank, 29... Expansion valve, 30... Electric fan, 32... Control unit (temperature difference calculation means, thermal change rate calculation means, suction port closing control means) ), 33...Opening/closing valve, 40...Cam ring, 40a...Cam surface, 41.42...Plate, 43...Rotor , 44... Slit, 45... Vane, 46... Back pressure passage, 47... Communication hole, 48... Pump chamber, P*, Pz... Suction port (inlet), S+
, St...Discharge port.

Claims (1)

[Claims] In an air conditioning compressor that constitutes a refrigeration cycle together with an evaporator and compresses fluid circulating in the refrigeration cycle that is sucked in from an inlet in a compression chamber and then discharges it, the temperature of the evaporator or the temperature of the air blown out from the evaporator temperature detection means for detecting; temperature difference calculation means for comparing and calculating the difference between the temperature detected by the temperature detection means and a preset target value;
a thermal change rate calculating means for calculating a thermal change rate with respect to time of the air blown from the evaporator; and an inlet closing control means for controlling the inlet to close at a predetermined rate per arbitrary unit time. , wherein the suction port closing control means changes a predetermined rate at which the suction port is closed based on the temperature difference calculated by the temperature difference calculation means and the thermal change rate calculated by the thermal change rate calculation means. An air conditioning compressor characterized by maintaining a temperature near a target value.