JPS6146018Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a control device for a vehicle air conditioning compressor,
In particular, it relates to a device for controlling capacity.

In general, vehicle air conditioners have internal and external air switching doors,
Consisting of a blower, evaporator, heater core, air mix door, mode switching door, etc., the compressor that cools the evaporator is driven by receiving rotational force from a pulley rotated by the engine. An electromagnetic clutch is interposed between them.

The conventional compressor control device controls the electromagnetic clutch on and off, and compares the output signal from the sensor that detects the temperature at or near the evaporator surface with a reference value, and determines the temperature at or near the evaporator surface. The electromagnetic clutch is turned off when the temperature falls to the above reference value, for example, close to freezing temperature, and turned on when the temperature is higher than that, and by repeating this on-off operation, the surface side of the evaporator is The temperature was maintained at a predetermined level. This kind of drive is usually called cycling drive.

However, with such a configuration, when the electromagnetic clutch is switched from off to on during cycling, the rotational force of the pulley is suddenly applied to the compressor, causing the compressor to compress the liquid or cause a sudden increase in torque. There was also a risk that the life of the compressor would be shortened. Furthermore, the load on the engine fluctuates rapidly, resulting in a large shock to the vehicle.

The purpose of the present invention is to eliminate the above-mentioned drawbacks by setting the compressor so that cycling drive is performed at a small capacity when the compressor enters the cycling drive state, and will be explained in detail below using examples. do.

FIG. 1 is a block diagram showing an embodiment of a control device for a vehicle air conditioning compressor according to the present invention.
In the figure, an air conditioner 1 includes an inside/outside air switching door 2,
It is composed of a blower 3, an evaporator 4, a heater core 5, an air mix door 6, and a mode switching door 7. The evaporator 4 together with an expansion valve 8, a condenser 9, a liquid receiver 10, and a compressor 11 constitutes a cooling cycle. Rotational force from a pulley 12 rotated by the engine is transmitted to the compressor 11 via an electromagnetic clutch 13. Further, this compressor 11 has a capacity variable mechanism 14, and this capacity variable mechanism 14 has a capacity setting device 15.
controlled by. The variable capacity mechanism 14 is composed of, for example, a solenoid valve for a refrigerant bypass flow path provided between an arbitrary compression chamber among a plurality of compression chambers of the compressor and a refrigerant inlet, and this solenoid valve is connected to a capacity setting device. 15, it is possible to substantially adjust the capacity of the compressor. The variable capacity mechanism 14 is a regulator or compressor 1 that adjusts the pulley ratio of the pulley 12.
In the case where the compressor 1 is a swash plate type compressor, it may be constructed from an adjuster or the like that adjusts the inclination angle of the swash plate.

Reference numeral 16 denotes a control device consisting of, for example, a microcomputer, and this control device 16 receives a set temperature signal T _D from a temperature setting device 17 provided on the control panel, a vehicle interior temperature signal tr from an inside air sensor 18, and outside air. Outside air temperature signal from sensor 19
ta, a temperature signal te from a sensor 20 that detects the temperature on or near the surface of the evaporator 4, and by calculating these signals, a signal Sa for setting the opening degree of the air mix door 6 is generated.
Output. The control device 16 also receives setting level signals t ₁ , t ₂ (however, t ₁ >t ₂ ) from the operation level setter 21 and setting level signals t ₃ , t ₄ (however, t 2 ) from the operation level setting device 22. t ₃ >t ₄ , t ₄ >t ₂ and t ₃ >t ₁ ), and a signal from the air conditioner start switch 23 is also supplied. The above signal _t4 is level adjuster 2
The level regulator 24 increases or decreases the set level signal t ₄ based on the output signal 25 a from the engine rotation speed detector 25 . That is, as the engine speed increases, the set level signal _t4 is increased.

The operation of the control device for a vehicle air conditioning compressor having the above configuration will be explained with reference to FIG.
First, when the air conditioner start switch 23 is turned on,
The control device 16 turns on the electromagnetic clutch 13, drives the compressor 11, and cools the evaporator 4. The temperature of the evaporator 4 decreases and the sensor 20
The signal te from evaporator 4 gradually decreases.
When the set level signal _t2 corresponding to the freezing temperature (0-1°C) is reached, the control device 16 activates the electromagnetic clutch 13.
is off. As a result, evaporator 4
When the temperature on the surface side of the electromagnetic clutch ₁₃ increases and reaches a preset level signal t1 (for example, 3 to 4 DEG C.), the electromagnetic clutch 13 is turned on again. By repeatedly turning on and off the electromagnetic clutch 13, that is, by cycling the electromagnetic clutch 13, the temperature of the evaporator 4 is maintained within the temperature range corresponding to the set level signals _t1 and _t2 . On the other hand, immediately after the air conditioner start switch 23 is turned on, the capacity of the compressor 11 is normally set to a large capacity because the temperature signal te is large, and since the compressor is started with a large capacity, rapid cooling can be achieved and the interior of the vehicle can be cooled quickly. The temperature can be quickly brought close to the set temperature. In this case, when the evaporator 4 is cooled and its temperature signal te reaches a preset set level signal t ₄ (corresponding to approximately 5° C.), the control device 16 drives the capacity setter 15 . The capacity setter 15 controls the variable capacity mechanism 14 to reduce the capacity of the compressor 11. Therefore, when the temperature on the evaporator 4 side reaches the temperature range of the set level signals t ₁ and t ₂ and the compressor 11 is driven in cycling, the compressor has a small capacity at this time, so the compressor repeatedly turns on and off. It becomes possible to protect the compressor without causing liquid compression or sudden torque changes, and the shock to the vehicle side is reduced. Here, the compressor generates a set level signal that is larger than the set level signal _t4 by a predetermined value as the temperature signal te increases.
When the temperature corresponding to t ₃ (for example, 8° C.) is reached, the controller 16 controls the capacity setter 15 to switch the capacity of the compressor 11 from a small capacity to a large capacity. In this way, by creating a temperature difference between switching from large capacity to small capacity and switching from small capacity to large capacity, when the evaporator temperature reaches a predetermined temperature, the compressor will hunt, that is, change between large capacity and small capacity. This can solve the problem of frequent repetition. Further, the drive range can be widened with a small capacity, and power saving can be achieved.

Further, immediately after the air conditioner start switch 23 is turned on, acceleration is carried out, and when the engine speed increases, the set level signal _t4 is pulled up by the level regulator 24, so the compressor is activated immediately after the start switch 23 is turned on. Since the capacity can be switched from large capacity to small capacity in a relatively short time, the load on the engine can be further reduced without impairing running performance.

As explained above, the control device for a vehicle air conditioning compressor according to the present invention includes a temperature sensor that detects the temperature on or near the surface of the evaporator, and the temperature detected by this temperature sensor is maintained at a set temperature. a control means for controlling the electromagnetic clutch on and off so as to control the temperature; a capacity setting means for setting the capacity of the compressor; a level setting means for setting a reference temperature level for switching the capacity of the compressor which is higher than the set temperature; The control means controls the capacity setting means to switch the compressor from large capacity to small capacity when the temperature detected by the sensor falls below the reference temperature level, so the compressor can be turned on and off in a small capacity state. Therefore, the shock given to the compressor is small, liquid compression and torque fluctuation can be prevented, and the compressor can be protected. Further, large fluctuations in the engine load can be prevented, acceleration can be performed smoothly, and power can be saved.

In addition, by adjusting the above reference temperature level according to the engine speed, it is possible to operate with a small capacity without increasing the capacity when the engine speed is high, making acceleration running smoother. can. In the present invention, the reference temperature level has been described as being adjusted according to the engine speed, but it may also be adjusted based on room temperature, engine load, or a comprehensive signal. Furthermore, not only the temperature t ₄ but also the temperature t ₃ may be adjusted at the same time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a control device for a vehicle air conditioning compressor according to the present invention, and FIG. 2 is a characteristic diagram for explaining its operation. 1... Air conditioner, 4... Evaporator, 5...
...Heater core, 6...Air mix door, 11...
... Compressor, 12 ... Pulley, 13 ... Electromagnetic clutch, 14 ... Capacity variable mechanism, 15 ... Capacity setting device, 16 ... Control device, 17 ... Temperature setting device, 18 ... Internal air sensor, 19 ... outside air sensor,
20... Evaporator temperature sensor, 21, 22...
...Operation level setter, 24...Level adjuster.

Claims (1)

[Scope of utility model registration request] a temperature sensor that detects the temperature on or near the surface of the evaporator; a control means that controls an electromagnetic clutch on and off so that the temperature detected by the temperature sensor does not fall below a predetermined temperature;
The control means includes a capacity setting means for setting the capacity of the compressor, and a level setting means for setting a reference temperature level for switching the capacity of the compressor which is higher than the predetermined temperature, and the control means is detected by the temperature sensor. 1. A control device for a compressor for vehicle air conditioning, characterized in that the compressor is switched from a large capacity to a small capacity by controlling a capacity setting means when the temperature of the compressor is below the reference temperature level.