JPH06241171A - Drive torque calculator for variable displacement compressor - Google Patents

Abstract

PURPOSE:To improve the calculation accuracy for the drive torque of a variable displacement compressor by utilizing the fact that the torque variation range at the time of operating the compressor in a maximum capacity region is generally small. CONSTITUTION:The temperature of the outside atmosphere of a vehicle is detected by an outside air temperature sensor 100. The temperature in the vicinity of the outlet of cooling air current from an evaporator 40 is detected by an after-evaporation temperature sensor 110. The maximum capacity operation timing of a compressor 20 is judged by a microcomputer 120 based on the detected temperature after evaporation, while the drive torque of the compressor 20 is calculated corresponding to the detected outside air temperature based on the data indicating the relationship between the drive torque and the outside air temperature at the time of maximum capacity operation of the compressor 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device provided with a refrigeration cycle for circulating a refrigerant according to the operation of a variable displacement compressor driven by a prime mover, and more particularly to a compressor employed in the device. The present invention relates to a torque calculating device for a variable displacement compressor, which is suitable for calculating the driving torque.

[0002]

2. Description of the Related Art Conventionally, in a vehicle equipped with an idle speed control device and an air conditioning control device, for example, a refrigeration cycle of the air conditioning control device is disclosed in Japanese Patent Laid-Open No. 62-41951. Whether the engine is operating or the change in the high-pressure side refrigerant pressure of the circulating refrigerant in the refrigeration cycle, the magnitude of the engine load is estimated, and the intake air flow rate to the engine in the idling state is estimated according to this estimation result. There is one that is controlled to prevent rough idle and engine stall of the engine.

[0003]

In such a structure, when the compressor of the refrigeration cycle is of a variable capacity type, the driving torque of the variable capacity type compressor is not affected by the high pressure side pressure of the circulating refrigerant. Although hardly affected, it is greatly affected by the capacity of the compressor, that is, the ratio of the refrigerant flow rate to the rotation speed of the compressor. Therefore, the above-mentioned configuration has a problem that the intake air flow rate to the engine in the idling state cannot be accurately controlled.

In view of the above, the present invention provides a torque calculation device for a variable displacement compressor in order to cope with such a situation.
Focusing on the fact that the torque fluctuation range of a variable displacement compressor when operating in the maximum displacement range is generally small, this is effectively utilized to improve the calculation accuracy of the drive torque of the compressor. is there.

[0005]

In order to solve the above problems, the structure of the present invention has a first detecting means for detecting the maximum capacity region of a variable displacement compressor driven by a prime mover of a vehicle, and an outside temperature of the vehicle. Alternatively, the relationship between the driving torque in the maximum capacity range of the compressor and the outside air temperature or the physical quantity related thereto when the maximum capacity range is detected by the second detecting means for detecting the physical quantity related thereto and the first detecting means. Torque calculation means for calculating the drive torque of the compressor according to the detection result of the second detection means based on the data indicating

[0006]

According to the present invention, the first detecting means detects the maximum capacity region of the variable displacement compressor and the second detecting means detects the outside temperature of the vehicle or the outside temperature of the vehicle. When a physical quantity related to is detected, the torque calculation means calculates the drive torque of the compressor according to the detection result of the second detection means based on the data when the maximum capacity area is detected by the first detection means. To do.
In such a case, since the fluctuation range of the drive torque in the maximum capacity region of the compressor is small, the drive torque calculated based on the data will be calculated with high accuracy. Therefore, with such a calculated drive torque, the state corresponding to the idling state of the engine of the prime mover can be accurately and smoothly controlled.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 10 denotes a vehicle engine (hereinafter,
An intake pipe of an engine EG) is shown, and a throttle valve 10a is arranged in the intake pipe 10. The throttle valve 10a adjusts the amount of intake air into the intake pipe 10 in accordance with the degree of opening of the accelerator pedal of the vehicle driver. Then, an air-fuel mixture is formed based on the amount of intake air into the intake pipe 10 and the amount of injected fuel accompanying it,
This air-fuel mixture is supplied into the combustion chamber of the engine EG and burned. The idle adjusting valve 10b is composed of a proportional solenoid valve, and the idle adjusting valve 10b is installed in the bypass pipe line 10c of the intake pipe 10 and sucks the throttle valve 10a from the upstream side to the downstream side according to the opening degree. Adjust the amount of air flow bypass.

The refrigeration cycle Rc constitutes a part of the air conditioning control device of the vehicle, and the refrigeration cycle Rc
Includes a variable capacity compressor 20. This compressor 2
0 is driven by the power transmission from the engine EG via the belt mechanism 30 by the engagement of the electromagnetic clutch 20a attached to the compressor 20. Then, the compressor 20 sucks and compresses the refrigerant from the evaporator 40 through the pipe P1 and discharges the compressed refrigerant into the pipe P2 at high temperature and high pressure. In such a case, the compressor 20 changes its capacity from the minimum capacity Vmin = 0 (%) to the value of the pressure of the suction refrigerant from the pipe P1.
The maximum capacity Vmax is changed within the range of 100 (%). The condenser 50 receives an air-cooling action of a cooling fan (not shown), condenses the compressed refrigerant in the pipe P2 and causes it to flow into the gas-liquid separator 60 as the condensed refrigerant through the pipe P3.

The gas-liquid separator 60 separates the inflowing condensed refrigerant into a gas phase component and a liquid phase component, and causes the liquid phase component to flow into the expansion valve 70 through the pipe P4 as a circulating refrigerant. The expansion valve 70 expands the inflowing circulating refrigerant at an opening degree according to the detected refrigerant temperature of the temperature sensitive cylinder 70a and causes the refrigerant to flow into the evaporator 40 through the pipe P5. The temperature sensing cylinder 70a detects the temperature of the refrigerant in the pipe P1 and adjusts the opening degree of the expansion valve 70 according to the detected refrigerant temperature. The evaporator 40 is
The evaporator 40 is disposed on the downstream side of the blower 90 in the air duct 80 of the air-conditioning control device. The evaporator 40 has a flow of air blown from the blower 90 into the air duct 80 in accordance with the evaporation action of the inflowing expanded refrigerant. Is cooled and allowed to flow to the downstream side. The evaporator 40 returns the evaporated refrigerant to the compressor 20 through the pipe P1.

Next, an electric circuit configuration for the idle adjusting valve 10b, the electromagnetic clutch 20a and the blower 90 will be described. The operation switch SW is operated when operating the air conditioner to generate an operation signal. The outside air temperature sensor 100 is located between the condenser 50 and the front grill of the vehicle, and the outside air temperature sensor 100 detects the temperature of the outside air of the vehicle and generates an outside air temperature detection signal. The post-evaporator temperature sensor 110 is arranged in the air duct 80 in the vicinity of the outlet of the cooling air flow from the evaporator 40.
The temperature near the 0 outlet is detected and a post-evaporator temperature detection signal is generated.

The microcomputer 120 executes a computer program according to the flowchart shown in FIG. Then, during this execution, the microcomputer 120 causes the idle adjusting valve 10b and the electromagnetic clutch 20 to operate.
a and each drive circuit 13 connected to the blower 90, respectively
Arithmetic processing necessary for controlling 0, 140, and 150 is performed. However, the computer program described above is stored in advance in the ROM of the microcomputer 120. It should be noted that the microcomputer 120 is powered by the battery B when the ignition switch IG of the vehicle is closed to be in an operating state, and starts executing a computer program in response to an operation signal from the operation switch SW.

In the present embodiment configured as described above,
The engine EG is closed by closing the ignition switch IG.
Is placed in an idling state and the microcomputer 120 is placed in an operating state. At this stage, when an operation signal is generated from the operation switch SW, the microcomputer 130 executes Step 2 according to the flowchart of FIG.
At 00, execution of the computer program is started, and at step 210, a clutch output signal for engaging the electromagnetic clutch 20a and a blower output signal for operating the blower 90 are generated. Then, the electromagnetic clutch 20
a is driven and engaged by the drive circuit 140 in response to the clutch output signal from the microcomputer 120, and the compressor 20 is driven by transmitting power from the engine EG via the belt mechanism 30 and the electromagnetic clutch 20a. . Further, the blower 90 is the microcomputer 120.
Is driven by the drive circuit 150 in response to the blower output signal from the air blower to output an air flow toward the evaporator 40.

Next, in the refrigeration cycle Rc, the compressor 20 sucks and compresses the refrigerant in the pipe P1 and discharges it as high-temperature and high-pressure compressed refrigerant into the condenser 50 through the pipe P2. Under the cooling action of the fan, the inflowing compressed refrigerant is condensed and used as condensed refrigerant in the pipe P.
3 is made to flow into the gas-liquid separator 60. Then, the gas-liquid separator 60 causes the liquid phase component in the inflowing condensed refrigerant to flow into the expansion valve 70 through the pipe P4 as a circulating refrigerant, and
The expansion valve 70 expands the inflowing refrigerant at an opening degree according to the detected refrigerant temperature of the temperature sensing cylinder 70a and causes the refrigerant to flow into the evaporator 40 through the pipe P5. Therefore, the evaporator 40 cools the blast air flow from the blower 90 in accordance with the evaporating action of the inflowing refrigerant, and causes it to flow to the downstream side.

After the processing at step 210, the microcomputer 120 at step 220 detects the outside air temperature detection signal from the outside air temperature sensor 100 and the post-evaporation sensor 11.
The post-evaporator temperature detection signals from 0 are digitally converted and set as the outside air temperature Tac and the post-evaporator temperature Tae, and the computer program proceeds to step 230. At this stage, if the post-evaporation temperature Tae is equal to or higher than the predetermined temperature Taeo, the microcomputer 120 determines “YES” in step 230. On the other hand, if the post-evaporation temperature Tae is lower than the predetermined temperature Taeo, the determination in step 230 is “NO”.

However, the above-mentioned predetermined temperature Taeo is determined as follows. Refrigeration cycle Rc in this embodiment
In the above, the capacity of the compressor 20 (hereinafter, referred to as capacity Vc) is set to the post-evaporator temperature Tae of 2 to 3 (° C.) in relation to the pressure of the refrigerant sucked from the pipe P 1 into the compressor 20. Controlled as. Therefore, the predetermined temperature Taeo is set to 5
(° C) was set. Accordingly, if Tae ≧ Taeo, it is determined that the compressor 20 is operating at the maximum capacity Vmax because the cooling load of the evaporator 40 is large. Further, the reason why the maximum capacity Vmax is adopted as the criterion is that the compressor 20 has the maximum capacity Vma.
When operating at x, the fact that the fluctuation range of the drive torque of the compressor 20 (hereinafter referred to as drive torque T) is small is utilized to improve the calculation accuracy of the drive torque. The predetermined temperature Taeo is stored in the ROM of the microcomputer 120 in advance.

As described above, when the determination in step 230 is "YES", the microcomputer 120
Advances the computer program to step 240.
In this embodiment, the upper limit torque-outside air temperature characteristic Ta-Tac and the lower limit torque-outside air temperature characteristic Tb-Tac are experimentally obtained and introduced in the present embodiment as shown in FIG. In this case, the upper limit torque Ta and the lower limit torque Tb represent the upper limit value and the lower limit value of the fluctuation width Wvmax of the drive torque T that fluctuates according to the change of the outside air temperature Tac at the maximum capacity Vmax of the compressor 20.
The upper limit torque-outside air temperature characteristic Ta-Tac and the lower limit torque-outside air temperature characteristic Tb-Tac are stored in the ROM of the microcomputer 120 in advance. Then, in step 240, the microcomputer 120 determines the upper limit torque Ta and the lower limit torque T according to the outside air temperature Tac in step 220 based on the upper limit torque-outside air temperature characteristic Ta-Tac and the lower limit torque-outside air temperature characteristic Tb-Tac.
b is calculated, and the upper limit torque Ta and the lower limit torque Tb are calculated.
The arithmetic mean value of is calculated and is set as the estimated torque Tab.

On the other hand, as described above, when the determination in step 230 is "NO", the microcomputer 1
20 advances the computer program to step 250. In the calculation processing in step 250, in the present embodiment, as shown in FIG. 4, the upper limit torque-outside air temperature characteristic Tc-Tac and the lower limit torque-outside air temperature characteristic T.
d-Tac was experimentally determined and introduced. In this case, the upper limit torque Tc and the lower limit torque Td fluctuate according to the change of the outside air temperature Tac in the capacity variable range of the capacity Vc of the compressor 20 = 0 (%) to 99.9 (%). Width W
Shows the upper and lower limits of var. The upper limit torque-outside air temperature characteristic Tc-Tac and the lower limit torque-outside air temperature characteristic Td-Tac are stored in the ROM of the microcomputer 120 in advance.

Therefore, the microcomputer 120
However, in step 250, the upper limit torque-outside air temperature characteristic Tc
-Tac and lower limit torque-outside temperature characteristic Td-Tac, the upper limit torque Tc and the lower limit torque Td are calculated according to the outside temperature Tac in step 220, and the arithmetic mean value of these upper limit torque Tc and the lower limit torque Td is calculated and estimated. Set with torque Tcd. Note that, as described above, the respective estimated torques Tab and Tcd are taken as the arithmetic mean values because the estimated torques Tab and Tcd are changed even if the drive torque T fluctuates.
This is because the deviation of Tcd is small.

Step 240 or 250 as described above.
Upon completion of the calculation process in (1), the microcomputer 120 determines in step 260 the valve opening degree of the idle adjusting valve 10c corresponding to the bypass intake flow rate into the bypass conduit 10c corresponding to the estimated torque Tab or Tcd. Generates the opening output signal. Then, the drive circuit 13
Based on the valve opening output signal from the microcomputer 120, 0 controls the valve opening of the idle adjusting valve 10c to a value corresponding to the estimated torque Tab or Tcd. Therefore, the intake air flow into the intake pipe 10 is bypassed through the bypass pipe 10c by an amount corresponding to the valve opening degree of the idle adjusting valve 10c according to the estimated torque Tab or Tcd,
An air-fuel mixture is formed and is supplied and burned in the combustion chamber of the engine EG. As a result, the idling state of the engine EG is controlled to a state corresponding to the estimated torque Tab or Tcd. Further, under such idling control state of the engine EG, the compressor 20 receives power from the engine EG via the electromagnetic clutch 20a, and the estimated torque T
Since it operates with a drive torque corresponding to ab or Tcd, the cooling capacity of the evaporator 40 can be ensured to match its load.

As described above, the variable displacement compressor 2
By utilizing the fact that the fluctuation range of the drive torque at the time of the maximum capacity Vmax of 0 is generally small, the predetermined temperature Taeo and the post-evaporator temperature Tae which are closely related to the maximum capacity Vmax are compared and determined. Therefore, Tae ≧ Tae
When o is satisfied, that is, when the maximum capacity Vmax of the compressor 20 is reached, the estimated torque Tab is calculated from the Ta-Tac characteristic and the Tb-Tac characteristic shown in FIG. 3, so the estimated torque Tab is calculated.
The accuracy of can be maintained high. As a result, when the compressor 20 is at the maximum capacity, the engine EG is controlled so as to maintain its idling state at a state corresponding to the estimated torque Tab, and transmits power to the compressor 20 via the electromagnetic clutch 20a. , The compressor 20 is operated with a drive torque corresponding to the estimated torque Tab. As a result, even if the load on the evaporator 40 increases, the evaporator 4
It is possible to secure a cooling capacity of 0 so as to match the load and prevent the occurrence of rough idle and engine stall, while maintaining a smooth idling state of the engine EG. In such a case, the estimated torque Tab is obtained as the arithmetic mean value as described above, so that the accuracy of the estimated torque Tab can be further improved by a simple method of arithmetic mean. On the other hand, when Tae ≧ Taeo is not satisfied, that is, when the capacity of the compressor 20 is in the variable range, the estimated torque Tcd is set to Tc-T in FIG.
Since the arithmetic mean value is calculated from the ac characteristic and the Td-Tac characteristic, the accuracy of the estimated torque Tcd can be further improved by a simple method of arithmetic mean.

In the above embodiment, in calculating the estimated torques Tab and Tcd, the upper limit torque-outside temperature characteristics Ta-Tac and Tc-Tac and the lower limit torque-outside temperature characteristics Tb-Tac and Td-Tac are calculated. However, the present invention is not limited to this, but instead of the upper limit torque-outside air temperature characteristics Ta-Tac and Tc-Tac, the characteristic and the upper limit that represent the relationship between the upper limit torque Ta and the high-pressure side pressure of the refrigerant in the refrigeration cycle Rc. A characteristic representing the relationship between the torque Tc and the high-pressure side pressure of the refrigerant in the refrigeration cycle Rc is adopted, and each lower limit torque-outside air temperature characteristic Tb-Ta.
Instead of c and Td-Tac, a characteristic representing the relationship between the lower limit torque Tc and the high pressure side pressure of the refrigerant in the refrigeration cycle Rc and a characteristic representing the relationship between the lower limit torque Td and the high pressure side pressure of the refrigerant in the refrigeration cycle Rc are adopted. You may carry out. In such a case, instead of the high-pressure side pressure of the refrigerant, a physical quantity that is closely related to the outside air temperature such as the load of the evaporator 40 may be adopted.

In implementing the present invention, the engine E
After the estimated torque of the compressor 20 in the idling state of G is calculated, the vehicle is placed in the running state, and when the engine EG is in the idling state again thereafter, the estimated torque of the compressor 20 is calculated again. Thus, when the estimated torque is calculated on the premise of the maximum capacity of the compressor 20 in both idling states, if the estimated torque at this time is used to perform subsequent idling control, the compressor 20 It becomes possible to realize the idling control with the highly accurate estimated torque regardless of whether the capacity of is in the maximum capacity or in the capacity variable range.

Further, in the above embodiment, the compressor 20
The determination is made by utilizing the post-evaporation temperature Tae, but the present invention is not limited to this.
Instead of ae, the temperature of the radiation fins of the evaporator 40,
At least one of the physical quantity such as the temperature of the low pressure side pipe of the refrigerant of the refrigeration cycle Rc, the temperature and pressure of the refrigerant in the low pressure side pipe may be selected and implemented. In such a case, the predetermined temperature T
The predetermined physical quantity of the selected physical quantity corresponding to aeo is set to the predetermined temperature T.
Used in place of aeo.

Further, in the above embodiment, the compressor 20
As the compressor, a compressor whose capacity is changed according to the pressure of the refrigerant sucked from the pipe P1 is adopted. Instead, a compressor whose capacity is changed according to the control of the microcomputer 120 is used as the compressor 20. It may be adopted and implemented.

In the above embodiment, step 2
The example in which the determination of “YES” in 30 specifies the maximum capacity Vmax of the compressor 20 has been described, but in such a case, it is sufficient to specify that the capacity of the compressor 20 is in the vicinity of the maximum capacity Vmax, and therefore, Pre-evaporation temperature after Ta
The eo may be changed and implemented as necessary.

Further, in carrying out the present invention, the prime mover of the vehicle is not limited to the engine EG, but an electric motor or the like may be adopted.

Further, in carrying out the present invention, the present invention is not limited to the refrigeration cycle Rc of the air conditioning control device, and the present invention may be applied to a refrigeration cycle of a vehicle refrigerator or freezer.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the microcomputer of FIG.

FIG. 3 is a graph showing a relationship between a drive torque T and an outside air temperature Tac when the variable displacement compressor operates at a maximum displacement Vmax.

FIG. 4 is a graph showing a relationship between a drive torque T and an outside air temperature Tac when the variable displacement compressor operates in a variable displacement range.

[Explanation of symbols]

EG ... Engine, 20 ... Variable capacity compressor, 20a ... Electromagnetic clutch, 30 ... Belt mechanism, 40 ... Evaporator,
100 ... Outside air temperature sensor, 110 ... Evaporator post-temperature sensor, 12
0 ... Microcomputer.

Claims (1)

[Claims] 1. A first detecting means for detecting a maximum capacity region of a variable displacement compressor driven by a prime mover of a vehicle, and a second detecting means for detecting an outside air temperature of the vehicle or a physical quantity related thereto. When the maximum capacity range is detected by the first detection means, the detection result of the second detection means is determined based on the data indicating the relationship between the drive torque in the maximum capacity range of the compressor and the outside air temperature or a physical quantity related thereto. A drive torque calculation device for a variable displacement compressor, comprising: torque calculation means for calculating the drive torque of the compressor.