JPS6146017Y2 - - Google Patents

Description

[Detailed explanation of the idea]

This invention is a control device for a vehicle air conditioning compressor.
In particular, the present invention relates to a device that controls a compressor based on the magnitude of the difference between the vehicle interior temperature and the set temperature of a temperature setting device and the engine load. A vehicle air conditioner consists of an inside/outside air switching door, a blower, an evaporator, a heater core, an air mix door, a mode switching door, etc. The compressor that cools the evaporator is driven by the rotational force from a pulley driven by the engine, and an electromagnetic clutch is provided between the pulley and the compressor. Thus, the rotational force can be controlled. The control device that controls the compressor usually compares and determines the temperature on the surface side of the evaporator with a set level and controls the electromagnetic clutch.
When the temperature on the evaporator side decreases and approaches the set level, the electromagnetic clutch is deenergized and the compressor is turned off to prevent the evaporator from being excessively cooled and freezing. Through such control, the compressor is constantly turned on and off, resulting in so-called cycling drive. Furthermore, the conventional compressor control device controls the compressor based on the difference between the vehicle interior temperature and the set temperature of a temperature setting device provided on the operation panel. That is, when the vehicle interior temperature becomes higher than the set temperature, the set level for turning off the compressor is lowered to increase the operating rate of the compressor. That is, by lowering the set level, the compressor is kept on until the evaporator is sufficiently cooled, and the time the compressor is on becomes longer, increasing the operating rate. Furthermore, when the vehicle interior temperature becomes approximately equal to or lower than the set temperature, the operating rate is lowered by raising the set level. This reduces the load on the engine and saves power. However, with such a control device, the operating rate of the compressor is controlled independently of the engine load, so if the cabin temperature rises above the set temperature, the engine load increases when accelerating or climbing hills. Even in this case, the operating rate is increased, and the engine load is further increased, making it difficult to perform acceleration uphill. The system also detects the engine load, compares and determines the engine load with a set level, and reduces the operating rate of the compressor when the engine load becomes greater than the set level. however,
In this type of control device, the cooling performance is determined by the engine load, so even when the cabin temperature is approximately equal to or lower than the set temperature, the compressor is activated when the engine load becomes smaller than the set level. Since the operation rate of the air conditioner is increased, not only is supercooling performed, but it is also not very desirable in terms of power saving. Furthermore, when the room temperature of the vehicle is high, the operating rate of the compressor decreases due to an increase in the engine load, or the compressor is stopped completely, so that cooling is suppressed or not performed at all, impairing comfort. The purpose of this invention is to reduce the compressor capacity when the engine load is higher than the set level, regardless of the size of the difference between the cabin temperature and the set temperature, and to reduce the compressor capacity regardless of the difference between the cabin temperature and the set temperature. This method eliminates the above drawback by reducing the capacity of the compressor even if the engine load is small when the temperature is approximately equal to the temperature inside the vehicle or the temperature inside the vehicle is below the set temperature, and will be explained in detail below using examples. . 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, reference numeral 1 denotes a control section, which is composed of a microcomputer or a relay circuit as shown in _FIG . A signal corresponding to the temperature on the surface side of the evaporator from the evaporator temperature sensor 4
te and a signal V _L from the negative pressure detector 5 are input. The negative pressure detector 5 is composed of a sensor that detects the engine's intake manifold negative pressure, and when the engine's acceleration pedal is depressed and the manifold negative pressure increases, the signal V _L increases in proportion to this. . That is, the negative pressure detector 5 detects the engine load. A signal from a setting device 10 for setting the rotation speed of a blower for introducing outside and outside air and a signal from an air conditioner start switch 14 are input to the control unit 1, and the control unit 1 adjusts the capacity of the compressor 6 based on these input signals. The electromagnetic clutch 9 that transmits the rotational force of the pulley 8 and the capacity setting device 7 that sets the torque are controlled. The compressor 6 has a variable capacity mechanism, and the variable capacity mechanism includes, for example, a solenoid valve provided in a flow path that bypasses a refrigerant inlet and some of the compression chambers of the compressor. By controlling the solenoid valve, some of the compression chambers can be disabled, thereby controlling the amount of refrigerant discharged and thereby adjusting the capacity of the compressor. The capacity setting device 7 sets the capacity of the compressor 6 by controlling a solenoid valve that constitutes the variable capacity mechanism. The variable capacity mechanism may be constructed from an adjuster for adjusting the pulley ratio of the pulley 8 or an adjuster for adjusting the inclination angle of the swash plate when the compressor 6 is a swash plate type compressor. In FIG. 2, the control unit 1 compares and determines the vehicle interior temperature signal tr and the set temperature signal T _D and turns off the contact 15 when the vehicle interior temperature becomes higher than the set temperature and tr > T _D. The room temperature setting circuit 16 compares and determines the signal V _L from the negative pressure detector 5 with the set level V _S and determines whether acceleration or hill climbing has occurred and the signal V _L increases and V _L > V _S. an engine load detection circuit 18 that turns on the contact 17 when
An evaporator temperature detection circuit 20 that compares and judges the signal te from the evaporator temperature sensor 4 with the set level tp, and turns off the contact 19 when the temperature on the evaporator side decreases and the signal te becomes smaller and te<tp. configured. Contact point 15, contact point 17 above
are connected in parallel to each other, one end of which is connected to the power source via the air conditioner start switch 14 and contact 21, and the other end is grounded via the capacity setting device 7. One end of the contact 19 is connected to the compressor starting switch 14, and the other end is grounded via the electromagnetic clutch 9. The blower rotation speed setting device 10 has a movable contact 10a, one end of which is connected to a power source, and fixed contacts 10b, 10c, 10d, 1.
0e, fixed contact 10c is resistor 22, 23
The fixed contact 10d is connected between the resistors 22 and 23, and the fixed contact 10e is connected between the resistor 23 and the motor 24. The movable contact 10a is the fixed contact 10c, 1
The resistance value connected to the motor 24 decreases as it slides in the 0d and 10e directions, so the motor 24 is operated at low speed, medium speed, and high speed. In this case, a common contact 10f is connected to the range where the movable contact 10a makes sliding contact with the fixed contacts 10c, 10d, and 10e, and this common contact 10f is grounded via a relay 25. controlled. That is, when the movable contact 10a is in sliding contact with the fixed contacts 10c to 10e and the blower is operated, the relay 25 is activated, the contact 21 is turned on, and the air conditioner starting switch 14 can be energized. The operation of the control device for a vehicle air conditioning compressor with the above configuration is as shown in the table below.

[Table] That is, the blower motor 24 is operated by operating the blower rotation speed setting device 10, and the movable contact 10
a is in sliding contact with the common contact 10f, the relay 25 is excited, the contact 21 is turned on, and the air conditioner start switch 14 is turned on, for example, the temperature inside the vehicle is higher than the set temperature of the temperature setting device 2, Assuming tr>T _D and normal driving, V _L
<V _S , the room temperature setting circuit 16 and the engine load detection circuit 18 operate to turn off the contacts 15 and 17, and the compressor is operated at a large capacity. Acceleration or hill climbing is performed here, the engine load increases, and the V
When _L >V _S , the engine load detection circuit 18 operates and turns on the contact 17, thereby energizing the capacity setter 7, which causes the capacity variable mechanism of the compressor 6 to operate and reduce the capacity of the compressor 6. In this way, even when the cabin temperature is higher than the set temperature, the engine load increases and the compressor capacity is set to a small capacity, so the engine load does not increase and acceleration and climbing can be performed smoothly. be able to. Next, when the interior temperature of the vehicle is higher than the set temperature, downhill driving, idling, and low speed driving are performed, and when V _L ≦ V _S , the engine load detection circuit 18 turns off the contact 17, so the capacity setting device 7 is not energized, and the capacity of the compressor 6 is set to a large capacity. Therefore, at this time, the cooling capacity of the compressor can be increased, sufficient cooling can be achieved, the temperature inside the vehicle can be lowered to the set temperature, and the feeling of the occupants can be improved. At this time, the compressor is turned on and off by the operation of the evaporator temperature detection circuit 20, and is driven cycling. Next, if we consider the case where the vehicle interior temperature is equal to or lower than the set temperature of the temperature setting device 2, in this case tr≦T _D , so the room temperature setting circuit 1
6 turns on the thermo switch 15, the capacity setter 7 is energized, and the capacity of the compressor 6 is set to a small capacity. Therefore, even if the engine load changes and the acceleration detection circuit 18 operates and the contact 17 is turned on or off, the compressor 6 is maintained at a small capacity.
Therefore, unlike in the past, when the cabin temperature is lower than the set temperature and the engine load is lower than the set level, the operating rate of the compressor is increased and the feeling is not lowered due to supercooling. There is no risk that power saving performance will be impaired. Further, even if the engine load increases at this time, since the compressor 6 is operated at a small capacity, acceleration and climbing can be performed smoothly. Furthermore, according to the present invention, by operating the compressor at a small capacity, the temperature drop in the evaporator becomes gradual, so the on-off cycle of the compressor becomes longer, and the engine load fluctuations do not become drastic, allowing smoother acceleration. In the present invention, as shown in FIG. 3, a contact 15a linked to a contact 15 controlled by a room temperature setting circuit 16 is connected in series to a relay 40, and a contact 17 controlled by an acceleration detection circuit 18 is connected in series. An interlocking contact 17a may be connected in series to the switch 15a, and a normally closed contact 41 controlled by the relay 40 may be connected to the electromagnetic clutch 9. With this configuration, the operations shown in the table below can be performed.

[Table] That is, when the vehicle interior temperature is lower than the set temperature and the engine load is higher than the set level, contact 15a is turned on, contact 17a is turned on,
Since the relay 40 is energized and the contact 41 is turned off, the electromagnetic clutch 9 can be deenergized, thereby stopping the operation of the compressor. Therefore, the load on the engine can be further reduced, acceleration or hill climbing can be performed smoothly, and since the temperature inside the vehicle is lower than or almost equal to the set temperature of the temperature setting device, the air conditioning performance is not affected too much. do not have. In this embodiment, the engine load is detected by detecting the engine intake manifold negative pressure, but the engine load may also be detected by detecting the engine rotational speed or accelerator pedal depression speed. good. Furthermore, it goes without saying that a differential is provided in the comparison and determination of each set value. As explained above, the compressor for vehicle air conditioning according to the present invention includes a first determining means for comparing and determining the vehicle interior temperature and the set temperature of the temperature setting device, and a second determining means for comparing and determining the engine load and the set level. a compressor capacity setting means for setting the capacity of the compressor; and a control means for controlling the compressor capacity setting means based on output signals from the first and second determination means, and the control means is arranged in a vehicle interior. Controlling the compressor capacity setting means to reduce the capacity of the compressor when the temperature is lower than the set temperature, and compressor capacity setting means when the vehicle interior temperature is higher than the set temperature and the engine load is higher than the set level. is controlled to reduce the capacity of the compressor, and when the vehicle interior temperature is higher than the set temperature and the engine load is lower than or approximately equal to the set level, the compressor capacity setting means is controlled to reduce the compressor capacity. Since the capacity is set to a large capacity, even if the temperature inside the vehicle is higher than the set temperature, if the engine load becomes higher than the set level, the capacity of the compressor is reduced to a small capacity, so that acceleration uphill can be performed smoothly. At this time, the temperature of the evaporator decreases slowly, so the compressor is not turned on and off frequently during cycling, making it easier to operate the accelerator. Furthermore, although the compressor has a small capacity, it is operated until just before the evaporator freezes, so the cooling performance is not impaired. In addition, when the cabin temperature is lower than the set temperature, the engine is operated at a small capacity even if the engine load is lower than the set level.
Since operation can be performed with a large capacity as in the past, overcooling does not occur.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing one embodiment of the control device for a vehicle air conditioning compressor according to the present invention, Fig. 2 is a circuit diagram showing the main parts of the above device, and Fig. 3 shows another embodiment of the present invention. It is a circuit diagram. 1...Control unit, 2...Temperature setting device, 3, 4...
Sensor, 5... Negative pressure detector, 6... Compressor, 7... Capacity setting device, 8... Pulley, 9... Electromagnetic clutch.

Claims (1)

[Scope of utility model registration request] a first determination means that compares and determines the vehicle interior temperature detected by the interior air sensor and the set temperature of the temperature setting device;
The second part that compares and judges the engine load and the set level.
The compressor capacity setting means comprises a determining means, a compressor capacity setting means for setting the capacity of the compressor, and a control means for controlling the compressor capacity setting means based on output signals from the first and second determining means, the control means When the vehicle interior temperature is lower than the set temperature, the compressor capacity setting means is controlled to reduce the compressor capacity, and when the vehicle interior temperature is higher than the set temperature and the engine load is higher than the set level, the compressor is set to a small capacity. The capacity setting means is controlled to reduce the capacity of the compressor, and when the vehicle interior temperature is higher than the set temperature and the engine load is less than or approximately equal to the set level, the compressor capacity setting means is controlled to reduce the compressor capacity. A control device for a vehicle air conditioning compressor, which is characterized by setting the capacity to a large capacity.