JPS58105819A - Controller of cooler for vehicle - Google Patents

Abstract

PURPOSE:To contrive an improvement of cooling capacity at the time of a low speed and control of overcooling at the time of a high speed, by so constituting that a blowoff temperature is controlled at a setting temperature automatically under the minimum cooling capacity by a compressor having variable compression capacity in a step by step state. CONSTITUTION:A driving circuit 64 of a solenoid valve VSV1 for changing compression capacity, a driving circuit 65 of a solenoid valve VSV2 and a driving circuit 66 of a solenoid clutch for driving and suspension of a compressor are controlled by a microcomputer MC storing a control program by receiving a signal from a blowoff air temperature detecting part 61 and a temperature setting part 62 through an A-D converter 63. A variable compression capacity type coolant compressor varies to CC=1, that is, capacity 100% by closing the solenoid valves VSV1 and VSV2, varies to CC=2, that is, capacity 70% by closing the solenoid valve VSV1 and opening the solenoid valve VSV2 and varies to CC=3, that is, capacity 40% by opening the solenoid valves VSV1 and VSV2. The coolant compressor is driven when a blowoff temperature Te is higher than a setting value T1 and is changed to deescalated compression capacity by one stage automatically when the compression capacity is not minimum. On the other hand, when a temperature does not drop, it is changed on the contrary to escalated capacity by one stage.

Description

[Detailed Description of the Invention] Generally, in a vehicle cooling system, a refrigerant compressor is driven by an automobile engine, and the number of revolutions of the compressor (for example, It is designed to provide optimal cooling capacity at 18Q Orpm). For this reason, when the engine is idling or running at low speeds, the compressor rotational speed is low, resulting in insufficient cooling capacity for the cooling load, and conversely, when driving at high speeds, there is excess cooling capacity. Conventionally, to deal with such excessive cooling capacity, a so-called air mix method was used, in which a portion of the air cooled by the refrigerant evaporator is heated through a heater in the heating system, and then mixed with the remaining cooling air. An electromagnetic crank that disconnects power transmission between the engine and compressor.

Turn the switch on and off, repeatedly driving and stopping the compressor.
By adopting the so-called clutch cycling method,
This is to eliminate the problem of excessive cooling when driving at high speeds.

However, the air mix method has the disadvantage of a large energy loss because it consumes a portion of the engine's power to reheat the cooled air. In addition, with the clutch cycling method, the excess capacity during high-speed driving is large, so the electromagnetic clutch is turned on and off many times. A control device for a vehicle cooling system that reduces the shock to the mechanical drive system and improves the cooling capacity during low-speed driving and idling, as well as suppressing and optimizing the cooling capacity during high-speed driving. This is what we are trying to provide.

Another object of the present invention is to provide a control device that can significantly reduce (5) clutching to the drive system.

The present invention allows the cooling capacity of the cooling device to be varied in stages, and by comparing the air temperature blown from the refrigerant evaporator with the set temperature, the cooling capacity can always be set to be optimal for the cooling load. This is what I did.

The present invention will be explained in detail below.

Figure 1 shows an example of the cooling capacity characteristics of the variable compression volume type refrigerant compressor used in the present invention with respect to the rotational speed. The cooling capacity in case of curve CC=1, CC=
2, CC=3. The cooling capacity of the medium volume is set to correspond to the cooling capacity of a conventional constant volume compressor.

This type of compressor has already been proposed by the applicant (
(Japanese Patent Application No. 56-33646) A scroll type compressor is used. Simply put, this compressor consists of a pair of spiral bodies that are interlocked at different angles.

One of the spiral bodies undergoes a relative rotational motion, and the sealed space formed between both (6) spiral bodies is moved toward the center with a decrease in volume, and compressed fluid is discharged from the center. It was designed to let you do so. The compressed volume can be reduced by configuring the first intake gas in the sealed space formed between the two spiral bodies to escape by means of a solenoid valve.

In this way, the suction gas escape holes, which are opened and closed by electromagnetic valves, are provided at two locations so that the compressed volume can be reduced in two stages.

Table 1 shows the relationship between the two solenoid valves VSVl and ■S■2 and the compression volume.

Table 1 Note that the shaded area in the figure indicates the range of cooling load.

Basically, it is determined by the outside temperature and the set temperature inside the car.

The present invention is applicable to cooling loads in this range.

The required minimum compression volume is always set and the required cooling capacity is obtained by switching the compression volume.

FIG. 2 is an operational flowchart of an embodiment of the present invention, which is used to control the interior temperature of a vehicle by detecting the temperature of the air blown from the refrigerant evaporator and driving and stopping the compressor.

The operation of the control device including three-stage compression volume switching control will be described. For convenience, the description will be made with reference to the numbers assigned to each step.

Step 1 is the initial setting of the compression volume at the time of starting the air conditioner.
．． A subroutine for vsv2 opening/closing control is executed, and the maximum compression volume is set based on Table 1. Stella f3 is the blowing air temperature T1-Td at which the compressor is stopped.
This is the setting of the blowing air temperature T2==Tu.

In step 4, it is determined whether the blowing air temperature Te is higher than the set value Tl.

If the value is higher, the process proceeds to Stella 5 and the compressor is driven by Stella f6. After the compressor is activated, the temperature of the blown air decreases,
While the value is equal to or greater than the set value T1, steps 4-5-6-4 are repeated.

When the blown air temperature becomes equal to the set temperature T, (=Td), the process proceeds to Stella 7611. Step 11 is to reset the set temperature upper limit value T2 (=Tu).

There is no particular meaning here since the setting is completed in step 3. In step 12, it is determined whether the compressed volume is the minimum, and since CC=1 at present, the program proceeds to Stella 7'13, where CC=2 is changed, and the subroutine shown in FIG. 3 is executed.

The compression volume is reduced by one step.

In normal temperature control by driving and stopping the compressor.

At this point, the compressor stops and the temperature of the blown air starts to rise; however, in the present invention, from step 15 onwards, the operation of setting the minimum compressor volume that can achieve the set temperature lower limit value TdVc is performed in a short time. That is, in step 14 CC=
2, the timer mechanism is set in step 15 and the process proceeds to step 16. Even if the compression volume is reduced, the blowout air temperature does not suddenly change, so proceed to steps 23 and 24 with the blowout air temperature Te (set temperature upper limit Tu), and step 1.
Steps '25-16-23-24, -2 are executed until the set time of the timer mechanism (for example, 5 seconds) elapses.
Cycles with 5. During this period, if the blowing air temperature Te becomes higher than the set temperature upper limit Tu, step 1.6-17-
Proceed as 18-1.9-20 and CC=IK in step 21
The compressor returns to the maximum compressed capacity and returns to step 4.

This loop is a loop in which temperature control is performed by switching the compression volume between CC=1 and CC=2. If the set time has elapsed, proceed to Step 26.

In step 26, the blowing air temperature Te is set to the lower limit of the set temperature T.
This is to determine whether the value is lower than d.

If it is lower, CC=2, which means that even if the compression volume is reduced by one step, the cooling capacity is still excessive, so the process advances to step 27.12 and CC=3 in step 13. 14, the compressed volume is further reduced by one step. Also, the blowing air temperature is higher than the set temperature lower limit Td.
If it is higher, it returns to Stella 7'16 (10), and operation continues with the compressed volume unchanged.

This state means that the blowing air temperature is maintained between the set value Td and Tu, but in step 16-23-24
During the loop circulation of -25-26-16, either step 016 or step 26 causes a transition to either increase the compression volume or stop the compressor.

Note that the timer control operations in steps 15, 24, and 25 are used to prevent unnecessary execution of the compression volume switching operation, and are used to prevent the blowout air temperature Te from becoming lower than the set temperature lower limit value Td due to temporary overshoot. Also, the compression volume is not switched. This is Stella mentioned below:
The same applies to the timer control operations of 7'21 and 7.8.

Next, when CC=3 and the minimum compression volume is reached.

The timer mechanism is set again in step 15, and Stella 7
In the roots circulation of '16-23-24-25-16, it is determined whether the blown air temperature becomes higher than the set temperature lower limit value Td within the set time tset by the timer mechanism. If the temperature rises within the set time, the cooling capacity is insufficient, so step 1.
7-18-19-20, the compression volume is returned to CC=2, and the process returns to step 4.

This loop is a loop in which temperature control is performed by switching the compression volume between CC = 2 and CC = 3. When tset has elapsed, step 26
Proceed to. If the cooling capacity is excessive even when CC=3, the process proceeds to step 27-12-22, where the electromagnetic clutch is de-energized and the compressor is stopped. Further, if the blowing air temperature is higher than the set value Tl (which does not necessarily match Td in this case) in step 26, the operation is continued with CC=3.

The subsequent control operation is the same as the operation described in the case of CC=2.

The Stella f27 is only a temporary replacement for the lower limit of the set temperature, and its intended purpose is as follows. In other words, the compression volume is first switched to decrease when the outlet air temperature reaches the lower limit value Td, but if the cooling capacity remains excessive even after the switch is made, the outlet air temperature becomes lower than the lower limit value Td. At a slightly lower value (Td-α), a second switch to the compression volume decreasing direction is performed. Whether or not the cooling capacity is excessive at this minimum compression volume must be determined not by comparison with the lower limit value Td but by comparison with (Td-α).

Therefore, when it is determined in step 26 that the cooling capacity is excessive, the outlet air temperature at that time is set as a new set value as a reference value for determining the ninth cooling capacity. Of course, this temporary setting is always changed to the original setting value Td in step 17 once the required minimum compression volume is set.

Now, when the compressor is stopped in step 22, the temperature of the blown air always rises, and the flow goes through the loop circulation of steps 16-23-16, then steps 16-17-18-6, and the CC
Driving the compressor with a minimum compression volume of =3.

Stop control is realized.

According to the control operation explained above, the cooling device is CC=]~C
C=2, CC=2 to CC=3. The minimum required compressor volume is set and operated in any of the operating modes from CC23 to compressor stop.

(13) Next, the control operations after step 7 will be explained.

FIG. 4 is a diagram showing temporal changes in the temperature of the blown air due to the above-mentioned control operation.

1 in Figure 4 For example, when CC = 2 or CC = 3 is set at point P, the cooling capacity is insufficient due to temporary low-speed running of 7f, and a main disturbance in temperature control as shown by the broken line occurs. There is. Therefore, after step 20 is executed, a timer mechanism is set in step 21 to prevent unnecessary switching of the compression volume in the event of a temporary overshoot of the blown air temperature at the set temperature upper limit value, and the process returns to step 4. Step 4-5-7-8-4
A loop circulation is performed. Note that the reason why the compressed volume is determined in step 5 is that the steps after step 7 are operations for increasing the compressed volume, and if CC=1, no further increase in volume is possible, so the steps after step 7 are performed. This is a step to prevent it from being executed.

Now, when the set time C3et (for example, 5 seconds) (14) by the timer mechanism has elapsed during the loop circulation of step 4-5-7-8-4, the process advances from step 8 to Stella f9.

If the blown air temperature is higher than the set temperature upper limit Tu, the compression volume is insufficient, and the process proceeds to step 10-19-20, where the compression volume is increased by one step, and the timer mechanism is set again in step 21, and step 04-5- A 7-8-4 loop circulation is performed. Note that step 10 is a temporary replacement operation for the reference setting value explained in the compression volume reduction control operation described above.

When the compression volume shortage is resolved and the blown air temperature reaches the set temperature lower limit in step 4, the setting is changed to the original set temperature upper limit T in step 11.

The temporary replacement of the set value performed in step 10 or 27 uses the extremely short-term deviation of the blown air temperature from the set value for control, and this process is performed when the compression volume is continuously switched. Since this is only carried out in the increasing or decreasing direction, there is no adverse effect on temperature control.

Further, this temporary replacement of the setting value can be easily replaced with another method. In other words, since the process described above is to detect excess or deficiency of cooling capacity with respect to the set temperature upper limit value or lower limit value, another set value that is slightly higher than the set excessive upper limit value is set to the set temperature lower limit value. A method of setting a different set value that is slightly lower depending on the number of stages of compression volume switching, or detecting the gradient of change in outlet air temperature at each compression volume switching near the upper and lower limit values to determine excess or deficiency of cooling capacity. The method can also be used for the same purpose. FIG. 5 is a diagram showing the change over time in the temperature of the blown air according to still another method.

In this method, the lowest limit value is set slightly lower than the lower limit value of the set temperature, and the cooling capacity is decreased one step at a time at this set temperature.By always stopping the compressor at the lowest limit value, Excess cooling capacity can be checked for each cycle. The figure shows the driving and stopping of the compressor and the switching of compression volume. Once the excess cooling capacity is detected at the lowest limit value, the next set temperature upper limit value is set with a compression volume that is one step smaller than the previous one. After switching the compression volume at point P, if the cooling capacity is not excessive, the temperature of the blown air increases as shown by the broken line, and operation is performed by switching between CC,=1 and CC=2.

FIG. 6 is a schematic block diagram of a device that enables the above-described control.

MC is a microcomputer that stores the control program shown in FIGS. 2 and 3, and includes a blowout air temperature detection section 61. The signal from the temperature setting section 62 is sent to the A-D converter 6.
3, a solenoid valve VSV for switching the compression volume,
The drive circuit 64. Solenoid Valve As explained above, the present invention quickly sets the cooling capacity of a cooling device whose cooling capacity is variable in stages to the required minimum cooling capacity based on a set value for temperature control, thereby achieving efficient cooling. It is possible to realize the operation of the cooling device. In addition, except when the cooling load is particularly low, temperature control is performed by switching the cooling capacity, which eliminates the problem of shock to the drive system caused by driving and stopping the compressor in the conventional clutch cycling system, and improves the air mix. 17) It has excellent effects, such as eliminating energy loss due to reheating of cooling air, which is seen in conventional temperature control.

In the embodiment, the case where a variable compression volume type compressor is used has been explained, but other means of varying the cooling capacity in stages, for example, by providing a bypass path between the inlet and outlet of the compressor to control the amount of bypass. It goes without saying that the same effect can be obtained by applying means for controlling the supply amount to the present invention, or means for controlling the supply amount by providing a throttle valve at the inlet of the compressor.

Furthermore, in the embodiment, a case was explained in which the cooling capacity is switched by detecting the entire temperature of the air discharged from the refrigerant evaporator. It is also possible to set an upper limit value and a lower limit value to the refrigerant evaporation pressure, detect this refrigerant evaporation pressure, and switch the cooling capacity.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the cooling capacity characteristics of the variable compression volume compressor used in the present invention, Fig. 2 is an operation flowchart of one embodiment of the present invention, Fig. FIG. 4 is a diagram showing an example of controlling the temperature of the blown air according to the present invention. FIG. 5 is a diagram showing an example of controlling the temperature of the blown air according to another embodiment of the present invention. The figure is a schematic block diagram of an embodiment of the present invention. In the figure, 61 is a temperature detection section, 62 is a temperature setting section, and 63 is A-
D converter. Reference numerals 64 and 65 indicate a drive circuit for an electromagnetic valve, and reference numeral 66 indicates a drive circuit for an electromagnetic clutch. (19)

Claims (1)

[Claims] 16. υ temperature control by making it possible to switch the cooling capacity of a vehicle cooling system in stages, and operating by alternately switching between a cooling capacity higher than the cooling load and a cooling capacity lower than the cooling load. A control device for a vehicle cooling system, characterized in that: 2. The upper limit of the control range for the air temperature blown from the refrigerant evaporator in the vehicle cooling system. A lower limit value is set, and the cooling capacity switching in the direction of decreasing cooling capacity performed at the lower limit value is repeatedly performed until the temperature of the blown air after the switching increases, so that the cooling load is lower than the cooling load. Claim 1, wherein the highest cooling capacity is determined, and the cooling capacity and the cooling capacity one step higher than the highest cooling capacity are alternately switched between an upper limit value and a lower limit value of the blown air temperature. Control device as described. 3. When the cooling capacity is repeatedly switched in the direction of decreasing the cooling capacity and it is detected that the blowout air temperature does not rise even with the minimum cooling capacity, the cooling capacity is changed between the upper limit and the lower limit of the blowout air temperature at the minimum cooling capacity. Claim 2 in which the operation of the refrigerant compressor and the stop of the refrigerant compressor are alternately repeated.
Control device as described in section. 4. Setting an upper limit value and a lower limit value to be a control range for the temperature of the air blown from the refrigerant evaporator in the vehicle cooling system, and changing the cooling capacity in the direction of increasing the cooling capacity to be performed at the upper limit value. Repeat this process until the temperature of the air being blown out later drops, and then determine the lowest cooling capacity that is higher than the cooling load. 2. The control device according to claim 1, wherein the cooling capacity is alternately switched between an upper limit value and a lower limit value of the blown air temperature. 5. Setting an upper limit value and a lower limit value that should be a control range for the temperature of the air blown from the refrigerant evaporator in the vehicle cooling system, and setting a lower limit value that is slightly lower than the lower limit value;
When the temperature of the blown air reaches the lower limit value, the cooling capacity is decreased by one step, and when the temperature reaches the upper limit value, the cooling capacity is increased by one step. When the cooling capacity is obtained +C, after switching the cooling capacity at the lower limit value, the blowout air temperature further decreases and reaches the layer lower limit value, the cooling capacity is switched to a decreasing direction, the refrigerant compressor is stopped, and the blowout air temperature is reduced. 2. The control device according to claim 1, wherein when the upper limit value is reached, the cooling capacity is switched to increase by one step and at the same time, the refrigerant compressor is re-driven. 6. The control device according to any one of claims 2 to 5, wherein an upper limit value and a lower limit value to be set as a control range are set for the refrigerant evaporation pressure of the refrigerant evaporator. 7 Claims 1 to 7, wherein the cooling capacity is varied by varying the compression volume of the refrigerant compressor in stages.
Any control device according to item 5. 8. Claims 1 to 5 in which the cooling capacity is variable by providing a piston passage connecting the inlet and outlet of the refrigerant compressor and varying the amount of refrigerant bypassed in stages.
Any of the control devices listed in Section 1. 9. A throttle valve device in the refrigerant circuit on the inlet side of the refrigerant compressor.