JPH037594Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a compressor control device that controls the compressor according to the cause of slippage in a power transmission device that transmits the driving force of a drive source to the compressor.

Conventionally, as a compressor control device, for example, as shown in Japanese Patent Application Laid-open No. 57-35181,
If the compressor seizes and the belt of the power transmission device is damaged, there is a risk of a serious vehicle accident. Therefore, the presence or absence of slippage in the power transmission device is detected, and if there is slippage, the electromagnetic clutch of the power transmission device is removed. It is known that the compressor is disconnected to stop driving the compressor. However, slippage in the power transmission mechanism occurs not only when the compressor cannot be operated due to seizure as mentioned above, but also when the load on the compressor simply becomes too large due to the discharge pressure of the compressor becoming high, or when the load on the compressor simply becomes too large. In some cases, such as when the voltage of the power supply that supplies current to the clutch drops, it may be possible to continue operating the compressor by reducing the load it carries. However, in the conventional system, the drive of the compressor is stopped even when it is possible to operate, which has the disadvantage that cooling cannot be performed thereafter.

Therefore, this invention aims to eliminate the conventional drawbacks caused by simply stopping the drive of the compressor, and to appropriately control the compressor by distinguishing between cases where it cannot be operated and cases where it is possible. A configuration for accomplishing this task is shown in FIG.

In FIG. 1, a compressor 1 is connected to a drive source 5 via a power transmission mechanism 4 consisting of a belt transmission device 2 and an electromagnetic clutch 3, and the driving force of this drive source 5 is transmitted to the power transmission mechanism. 4 is detected by a slip detection means 24. In addition, the compressor 1 is
The capacity of the compressor 1 can be changed by capacity variable means 17. And the control means 5
1, the presence or absence of slip is determined based on the output of the slip detection means 24, and if there is slip, first the capacity of compressor 1 is minimized, and if there is still slip, the drive of compressor 1 is stopped, and the capacity is set to the minimum. If there is no slippage at this stage, the energization of the electromagnetic clutch 3 and the adjustment amount of the capacity variable means 17 are controlled so that the capacity of the compressor 1 approaches the target value within a range where no slippage occurs. Therefore, if the compressor 1 cannot be operated due to seizure, the compressor 1
While the drive of the compressor 1 is stopped, the capacity of the compressor 1 approaches the target value within a range that does not cause slippage when the compressor 1 can be operated, so that the above-mentioned problem can be achieved.

Examples of this invention will be described below with reference to the drawings.

An embodiment of this invention is shown in FIG. 2, in which a compressor 1 is connected to a rotating shaft 6 of a drive source 5, which is a driving engine, through a power transmission mechanism 4 consisting of a belt transmission device 2 and an electromagnetic clutch 3. The driving force of the driving source 5 is transmitted through the power transmission mechanism 4, and the on/off control is performed by connecting and connecting the electromagnetic clutch 3.

The other end of the discharge passage 7 of the compressor 1 is connected to a condenser 10 provided in front of the fan 8 of the drive source 5 with a radiator 9 in between. It is connected to the evaporator 14 in the air conditioning case 13 to form a cooling cycle.

Further, the discharge passage 7 and suction passage 15 of the compressor 1 are short-circuited with a solenoid valve 16 in between, and the amount of discharged refrigerant flowing to the suction side is determined according to the opening degree of the solenoid valve 6. The capacity of the compressor 1 is adjusted in multiple stages such that as the opening degree of the valve 16 increases, the capacity of the compressor 1 becomes smaller, thereby forming a capacity variable means 17. In addition to this embodiment, the capacity variable means 17 may be used to change the number of cylinders of the compressor 1,
Alternatively, the pulley ratio of the belt transmission device 2 may be changed.

The microcomputer 18 is a central processing unit.
CPU, memory for storing program procedures and fixed data; ROM, for temporarily storing data;
It is equipped with RAM, input/output device I/O, and timer. A voltage signal from an ignition coil 20 whose primary current is cut off and connected by a distributor 19 is input to the microcomputer 18 as a pulse signal whose waveform is shaped by a waveform shaping circuit 21. The number is the driving source 5
is proportional to the number of rotations. Further, a voltage signal detected by a rotation sensor 22 formed of an electromagnetic pickup provided facing the rotating shaft of the compressor 1, for example, is input to the microcomputer 18 as a pulse signal whose waveform is shaped by a waveform shaping circuit 23. The number of pulses of this pulse signal is
is proportional to the number of rotations. Then, the microcomputer 18 compares the rotational speeds of the drive source 5 and the compressor 1, detects slippage in the power transmission mechanism 4, and detects slippage by the slippage detection means 2 shown in FIG.
4 are configured. In addition, the slip detection means 24
As other examples, (1) Comparison of the rotation speed of the drive shaft 5 and the rotation speed of the electromagnetic clutch 3 (2) Comparison of the rotation speed of the drive source 5 and the moving speed of the belt in the belt transmission device 2 ( 3) Comparison of the moving speed of the belt in the belt transmission device 2 and the rotation speed of the electromagnetic clutch 3; (4) Comparison of the rotation speed of the compressor 1 and the rotation speed of the electromagnetic clutch 3. They may also be combined.

Further, the set temperature signal set by the temperature setting device 25 and the detection signal detected by the thermal load detector 26 are converted into digital signals by an A/D converter 27 and input to the microcomputer 18. The heat load detector 26 is composed of an in-vehicle sensor that detects the temperature inside the vehicle, an outside air sensor that detects the outside air temperature, a solar radiation sensor that detects the amount of solar radiation, an evaporator sensor that detects the temperature of the evaporator 14, etc., and is normally controlled. In some cases, the electromagnetic clutch drive circuit 28, depending on the deviation of the detected temperature from the set temperature,
A control signal is sent to the electromagnetic valve drive circuit 29 to control the on/off of the electromagnetic clutch 3 and the opening degree of the electromagnetic valve 16.

Reference numeral 30 is an abnormality indicator, and if there is slippage in the power transmission mechanism 4 even when the capacity of the compressor 1 is minimized, an abnormality signal is sent from the microcomputer 18 and a lamp is turned on to indicate an abnormality in the compressor 1. It is for displaying.

In FIG. 3, the microcomputer 1
An example of the control operation in step 8 is shown as a flowchart, and when the microcomputer 18 is powered on, execution of the program starts from step 31. Next, in step 32, the set temperature from the temperature setter 25 and the detected temperature signal from the heat load detector 26 are inputted via the A/D converter 27, and a control signal is determined based on a predetermined calculation formula. , a control signal is sent to the electromagnetic clutch drive circuit 28 and the electromagnetic valve drive circuit 29 to perform normal control in which the on/off of the electromagnetic clutch 3 and the opening degree of the electromagnetic valve 16, that is, the capacity of the compressor 1 are controlled.

Next, the process advances to step 33, and the data temporarily stored in the memory RAM in step 32 is read to determine whether the compressor 1 is on or off. In this step 33, if it is determined that the drive of the compressor 1 is stopped, the process returns to step 32, and on the other hand,
If it is determined that the compressor 1 is operating, the process advances to the next step 34.

In step 34, in this embodiment, the rotational speed of the drive source 5 and the rotational speed of the compressor 1 are compared to determine whether or not there is slippage in the power transmission mechanism 4. As a result, if there is no slippage, the process returns to step 32, and if it is determined that there is slippage, the process proceeds to the next step 35.
Proceed to.

In step 35, the data temporarily stored in the memory RAM in step 32 is read to determine whether the capacity of the compressor 1 is the minimum capacity. As a result, if the capacity is the minimum, it means that there is slippage in the power transmission mechanism 4 even though the load carried by the compressor 1 is the smallest, so the compressor 1 is in a state where it cannot be operated due to seizure, etc. The process advances to step 36, where a stop signal is sent to the electromagnetic clutch drive circuit 28, the electromagnetic clutch 3 is disengaged, and the drive of the compressor 1 is stopped. Furthermore, proceed to step 37 and display the error indicator.
An abnormality display signal is sent to 30 to indicate that an abnormality has occurred in the compressor 1, and the process ends at the next step 38.

On the other hand, if it is determined in step 35 that the capacity is not the minimum, the process proceeds to step 39, where a control signal is sent to the electromagnetic valve drive circuit 29 to maximize the opening of the electromagnetic valve 16 and minimize the capacity of the compressor 1. In the next step 40, it is determined again whether or not there is slippage in the power transmission mechanism 4. If there is slippage even at this minimum stage, the process proceeds to step 36 and the drive of the compressor 1 is stopped. On the other hand, this step 40
If it is determined that there is no slippage in the power transmission mechanism 4, the reason is that the cooling cycle is clogged and the pressure of the refrigerant discharged into the discharge passage 7 increases, or the voltage of the power supply energizing the electromagnetic clutch 3 drops. In some cases, if the capacity of the compressor 1 is reduced, the compressor 1 can continue to operate, so the next process is performed without stopping the compressor 1.

That is, after performing timer processing in steps 41 to 44 and checking the driving state of the compressor 1 for a certain period of time, the target value may change, so the target value is calculated based on new data in step 50, and then 45
, it is determined whether the current capacity of the compressor 1 has reached the target value. If it has reached the target value, normal control is possible, and the process returns to step 32. On the other hand, if it has not reached the target value, the process returns to step 32. 46
Then, it is determined whether the target value is larger than the current capacity. As a result, if the target value is smaller than the current capacity, normal control is possible, so the process returns to step 32. On the other hand, if the target value is larger than the current capacity, the process proceeds to the next step 47. Go on,
A control signal is sent to the electromagnetic valve drive circuit 29 in order to increase the capacity of the compressor 1 by one step. Then, in the next step 48, it is determined again whether or not there is slippage in the power transmission mechanism 4. If there is no slippage, the process returns to step 41, and if there is slippage, the solenoid valve drive circuit 29 is activated to lower the capacity of the compressor 1 by one step. After sending out the control signal, the process returns to step 41, where the capacity of the compressor 1 is controlled to approach the target value within a range that does not cause slippage in the power transmission mechanism 4. Through the above processing, the control means 51 shown in FIG. It is configured.

In the above embodiment, the capacity variable means 17 of the compressor 1 adjusts the capacity of the compressor 1 in stages, but for example, the solenoid valve 1
It is also possible to make it a continuously variable type by continuously changing the duty ratio of energization to 6.

As mentioned above, according to this invention, if slippage occurs in the power transmission mechanism, it is determined whether or not the compressor can be operated, and the compressor is appropriately controlled, thereby preventing the compressor from seizing up. Not only can damage to the belts of the power transmission mechanism be prevented from occurring, but also when the discharge pressure simply increases, cooling continues, so the feeling of the occupants is not impaired. Further, by continuing to operate the compressor, the cause of the slippage may be eliminated, so in this case, it is possible to eliminate the need for repair.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a compressor control device according to this invention, and FIG. 2 is a configuration diagram of the same embodiment.
FIG. 3 is a flowchart showing an example of the control operation same as above. 1...Compressor, 2...Belt transmission device,
3... Electromagnetic clutch, 4... Power transmission mechanism, 5...
... Drive source, 17 ... Capacity variable means, 24 ... Slip detection means, 51 ... Control means.

Claims (1)

[Scope of utility model registration request] Slip detection means for detecting slip in a power transmission mechanism consisting of a belt transmission device and an electromagnetic clutch that transmits the driving force of the drive source to the compressor;
The capacity variable means for changing the capacity of the compressor and the output of the slip detection means are used to determine the presence or absence of slip, and if there is slip, first the capacity of the compressor is minimized, and if there is still slip, the compressor is not driven. control means for controlling the energization of the electromagnetic clutch and the adjustment amount of the capacity variable means so that when there is no slippage at the stage where the compressor is stopped and minimized, the capacity of the compressor approaches the target value within a range where no slippage occurs; A compressor control device comprising: