JPH0596936A - Torque calculating device for variable displacement type compressor - Google Patents

Abstract

PURPOSE:To precisely calculate the torque of a compressor acting as a load to an engine with a variation in the load condition of the air side of a heat- exchanger having a delay corresponding to the a time delay of a variation in the heat capacity of the heat-exchanger, in consideration with not only the high pressure side coolant pressure of a variable volume type compressor driven by the engine but also a variation in the capacity of the compressor. CONSTITUTION:When a refrigerating cycle Re circulates coolant through a condenser 50 in accordance with a capacity of the compressor 20, a microcomputer 130 determines a discharge pressure of coolant from a compressor 20, and a variation in a load condition of the air side of the condenser 50 is delayed by a variation in the heat capacity of the condenser 50. During the passage of this time delay the heat-exchange capability of the condenser 50 is determined. Further, the microcomputer 130 calculates the torque of the compressor 20 in accordance with the determined discharge pressure and the determined heat-exchanging capability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system having a refrigeration cycle in which a variable capacity compressor driven by an engine by a drive source such as a prime mover mounted on a vehicle circulates a refrigerant through a heat exchanger. In particular, the present invention relates to a torque calculation device suitable for calculating the torque of the variable displacement compressor of the system.

[0002]

2. Description of the Related Art Conventionally, for example, in an idle speed controller as disclosed in Japanese Patent Laid-Open No. 62-41951, the torque of a fixed displacement compressor in a refrigeration cycle is the refrigerant pressure on the low pressure side of the compressor. Assuming that the engine torque is controlled to be almost constant, the torque of the compressor acting as the load of the engine changes almost in proportion to the refrigerant pressure on the high-pressure side of the compressor, and In the rotational speed control, there is a system in which the high-pressure side refrigerant pressure of the compressor is detected and utilized as a torque equivalent.

[0003]

By the way, in such a structure, when a variable displacement compressor is adopted as the compressor, its torque also changes depending on the change in the capacity of the compressor. However, in the above-described configuration, when controlling the idle speed of the engine, the pressure of the high-pressure side refrigerant of the compressor is taken into consideration, but the capacity of the compressor is not taken into consideration. Therefore, it cannot be said that the torque of the compressor is properly utilized for the idle rotation speed control, and the control accuracy of the idle rotation speed of the engine decreases. As a result, for example, high idle rotation speed when the capacity of the compressor is small leads to deterioration of fuel efficiency, while low idle rotation speed when the capacity of the compressor is large causes engine stall or unpleasant vibration. There is a problem.

Even if the torque is determined in consideration of not only the pressure of the high-pressure side refrigerant of the compressor but also the capacity of the variable displacement compressor, the change in the pressure of the high-pressure side refrigerant of the compressor causes a change in the heat exchanger. If it is delayed due to the heat capacity of the above, the change in the determined torque will also be delayed. As a result, when such delayed torque acts as a load on the engine,
There is a possibility that the idle speed control of the engine may also be delayed and the engine may not be maintained in a good idling state. In view of the above, the present invention provides a system including a refrigeration cycle in which a variable capacity compressor driven by a drive source such as a prime mover mounted on a vehicle circulates a refrigerant through a heat exchanger. In consideration of not only the high pressure side refrigerant pressure of the variable displacement compressor but also the change of the capacity of the compressor, the torque of the compressor acting as a load of the drive source is changed to the high pressure side refrigerant pressure of the compressor. It is intended to calculate accurately according to the delay of.

[0005]

In solving the above problems, the structural feature of the present invention is, as illustrated in FIG. 1, a variable displacement compressor driven by a drive source such as a prime mover mounted on a vehicle. In a system including a refrigeration cycle in which a refrigerant is circulated through a heat exchanger by means of discharge pressure determining means 1 for determining the discharge pressure of the refrigerant from the compressor,
When the air-side load condition of the heat exchanger changes, only the transitional delay time of the change of the heat exchange capacity caused by the heat capacity of the heat exchange section delays the change of the air-side load condition, and the delay time. Heat exchange capacity determination means 2 for determining the heat exchange capacity based on the change in the air side load condition when the above condition elapses, and torque calculation means for calculating the torque of the compressor according to the determined discharge pressure and the determined heat exchange capacity. 3 and 3 are provided.

[0006]

With the above configuration of the present invention, the discharge pressure is maintained in the state where the refrigeration cycle circulates the refrigerant through the heat exchanger according to the capacity of the compressor driven by the drive source. The determining means 1 determines the discharge pressure of the refrigerant from the compressor, and the heat exchanging capacity determining means 2 determines the heat exchanging capacity generated by the heat capacity of the heat exchanging portion when the air side load condition of the heat exchanger changes. When the change of the air side load condition is delayed by the transitional delay time of the change and the heat exchange capacity is determined based on the change of the air side load condition when the delay time elapses, the torque calculation means 3 The torque of the compressor is calculated according to the determined discharge pressure and the determined heat exchange capacity.

[0007]

As described above, since the calculation of the torque is performed in consideration of not only the determined discharge pressure but also the capacity of the compressor, a variable capacity compressor is adopted in the refrigeration cycle. In this case, the torque of the compressor can be accurately obtained. Therefore, by utilizing the calculated torque, the operation of the drive source can be accurately controlled. Further, when determining the heat exchange capacity of the heat exchanger, when the air-side load condition of the heat exchanger changes, the heat exchange capacity determining means 2 causes only the transient delay time of the change of the heat exchange capacity. Since the change of the air side load condition is delayed and the heat exchange capacity is determined based on the change of the air side load condition when the delay time elapses, the change of the air side load condition is changed as described above. The torque calculation is performed in conformity with the delay in the change of the heat exchange capacity due to the heat capacity of the heat exchanger, and as a result, the torque calculation accuracy of the compressor can be maintained high.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 2 shows the idle rotation speed of an engine mounted in the engine room of a vehicle for a refrigeration cycle Rc which constitutes a part of an air conditioner. An example is shown in which the present invention is applied to control in relation to the operation. The engine has an intake pipe 10, and a throttle valve 10 a is arranged in the intake pipe 10. Thus, the throttle valve 10a adjusts the intake air amount into the intake pipe 10 according to the opening degree of the accelerator pedal of the vehicle. This means that the engine forms an air-fuel mixture based on the intake air amount and the injected fuel amount into the intake pipe 10 and supplies the mixture to the combustion chamber for combustion. The idle adjusting valve 10b is interposed in the bypass pipe line 10c of the intake pipe 10. The idle adjusting valve 10b bypasses the intake air flow from the upstream side to the downstream side of the throttle valve 10a according to the opening degree. Tolerate.

The refrigeration cycle Rc is arranged in the engine room, and the refrigeration cycle Rc includes a variable capacity compressor 20. The compressor 20 is driven by power transmission from the engine via a belt mechanism in accordance with selective engagement of an electromagnetic clutch 30 attached thereto. Thus, the compressor 20 sucks and compresses the refrigerant from the evaporator 40 through the pipe P1 according to changes in the rotation speed and the capacity, and discharges the compressed refrigerant into the pipe P2 at high temperature and high pressure. The condenser 50 is arranged in the engine room between the engine and the front grill of the vehicle, and the condenser 50 condenses the compressed refrigerant in the pipe P2 with the cooling operation of the cooling fan 50a. Then, the condensed refrigerant is provided in the pipe P3. Further, the condenser 50 receives an outside airflow flowing into the engine room through the front grill and causes the condenser 50 to flow toward the engine when the vehicle is running. The gas-liquid separator 60 separates the condensed refrigerant from the pipe P3 into a gas phase component and a liquid phase component, and supplies this liquid phase component to the pipe P4 as a circulating refrigerant. The expansion valve 70 expands the refrigerant from the pipe P4 and gives it to the evaporator 40 through the pipe P5 at an opening degree according to the detection result of the temperature sensing cylinder 70a with respect to the temperature of the refrigerant in the pipe P1. The evaporator 40 cools the inflowing airflow in response to the evaporation action of the expanded refrigerant from the pipe P5, and also returns the same refrigerant to the compressor 20 through the pipe P1.

Next, an electric circuit configuration for the idle adjusting valve 10b and the electromagnetic clutch 30 will be described with reference to FIG. The operation switch SW is operated when operating the air conditioner to generate an operation signal. The rotation speed sensor 80a detects the rotation speed Nc of the compressor 20 and generates a rotation speed pulse at a frequency proportional to the detection result. The vehicle speed sensor 80b detects the actual vehicle speed of the vehicle and generates a vehicle speed pulse at a frequency proportional to the detection result. The outside air temperature sensor 90 is located between the condenser 50 and the front grill of the vehicle, and the outside air temperature sensor 90 detects the actual temperature of the outside air of the vehicle and generates it as an outside air temperature detection signal. The refrigerant temperature sensor 100 is attached to the surface of the condenser 50.
Is detected as the actual surface temperature of the condenser 50 and is generated as a refrigerant temperature detection signal indicating the temperature of the condensed refrigerant.

The waveform shaper 110a is a rotation speed sensor 80.
The rotational speed pulses from a are sequentially shaped to generate the rotational speed shaping pulses. The waveform shaper 110b sequentially shapes each vehicle speed pulse from the vehicle speed sensor 80b to generate a vehicle speed shaping pulse. The A-D converter 120 includes the outside air temperature detection signal from the outside air temperature sensor 90 and the refrigerant temperature sensor 1.
The refrigerant temperature detection signals from 00 are digitally converted and generated as an outside air temperature digital signal and a refrigerant temperature digital signal. The microcomputer 130 executes the computer program according to the flowcharts shown in FIGS. 3 and 4 in cooperation with the waveform shapers 110a and 110b and the AD converter 120, and during the execution,
The drive circuits 140 and 150 connected to the idle adjusting valve 10b, the electromagnetic clutch 30, and the cooling fan 50a, respectively.
And 160 to perform arithmetic processing required for control. However, the above computer program is executed by the microcomputer 13
0 ROM previously stored. It should be noted that the microcomputer 130 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.

By the way, in the present embodiment, the present inventors have made it possible to determine the torque of the compressor 20 in consideration of both the high pressure side refrigerant pressure and the capacity of the compressor 20, based on the following matters. .. Generally, when the torque of the compressor 20 is represented by T, this torque T is represented by the following equation 1.

[0013]

[Equation 1]

However, in this equation 1, K and m are constants, respectively, and K = 2/100 and m = 0.12.
Set to 3. Ph represents the discharge pressure of the compressed refrigerant of the compressor 20, that is, the high pressure side refrigerant pressure (kg / (cm · cm) ABS).
Ps represents the suction pressure of the refrigerant of the compressor 20, and Ps = 3
(Kg / (cm · cm) ABS). Further, Vc represents the discharge volume of the compressed refrigerant of the compressor 20. Therefore, the number 1
In the above, since the various values on the right side excluding the high-pressure side refrigerant pressure Ph and the discharge volume Vc have known values, the torque T can be determined if Ph and Vc are determined.

Therefore, the discharge volume Vc is equal to the refrigeration cycle R
In relation to the refrigerant flow rate Gr of c, the following equation 2 is satisfied.

[0016]

[Formula 2] Vc = Gr / (Nc · F) However, in Formula 2, Gr represents the refrigerant flow rate (kg / hour) of the refrigeration cycle Rc. Also, F = 9.2 / 10
It is 000. Therefore, if the rotational speed Nc of the compressor 20 and the refrigerant flow rate Gr are determined, the discharge volume Vc can be determined. Therefore, whether or not the refrigerant flow rate Gr can be determined becomes a major issue.

Therefore, the temperature on the surface of the condenser 50,
That is, the value of the outside air temperature digital signal from the A / D converter 120 (hereinafter referred to as the outside air temperature Tac) and the condensed refrigerant temperature in the condenser 50, that is, the value of the refrigerant temperature digital signal from the A / D converter 120. (Hereinafter, referred to as condensed refrigerant temperature Trc) is large (for example, Trc is considerably higher than Tac), the heat dissipation capacity of the condenser 50 is large, so that the refrigerant flow rate Gr is large, while the condensed refrigerant temperature is large. Focusing on the physical phenomenon that the refrigerant flow rate Gr is small when the difference between Trc and the outside air temperature Tac is small, an attempt was made to determine the refrigerant flow rate Gr based on the temperature difference between Tac and Trc.

In general, the condenser 50 cools and condenses the high-temperature and high-pressure compressed refrigerant from the compressor 20 and outputs it as a two-phase condensed refrigerant of a gas phase and a liquid phase. However, considering the heat radiation amount Qrc of the condenser 50 in relation to the refrigerant in the condenser 50, this heat radiation amount Qrc indicates that the refrigerant enthalpy difference between the refrigerant inflow port and the refrigerant outflow port of the condenser 50. △ i (kca
1 / kg) and the refrigerant flow rate Gr, the following equation 3
Is known to satisfy.

[0019]

## EQU3 ## Qrc = Δi · Gr In this case, Δi mainly corresponds to the latent heat of the condensed refrigerant,
For example, when the refrigerant is R12, as shown in FIG. 5A, it is specified by the curve La in relation to the condensed refrigerant temperature Trc. Therefore, if this curve La is approximated by the straight line Laa, the following equation 4 is obtained.

[0020]

## EQU00004 ## .DELTA.i = D.E.Trc As a result, the equation 3 is converted into the following equation 5.

[0021]

[Expression 5] Qrc = (D−E · Trc) · Gr On the other hand, considering the heat radiation amount Qac of the condenser 50 in relation to the outside air temperature Tac on the surface of the condenser 50, this heat radiation amount Qac is It is specified by the following equation 6.

[0022]

## EQU00006 ## Qac = Gac.PHI..0.24. (Trc-Tac) where Gac is the outside air flow rate into the condenser 50 (kg / h
our), and Φ represents temperature efficiency. here,
Considering that the flow velocity of the outside airflow corresponds to the vehicle speed of the vehicle, Gac · Φ is the velocity Vk (m / s) of the outside airflow on the surface (that is, the front surface) of the condenser 50, that is, the vehicle speed of the vehicle ( Hereinafter, in relation to the vehicle speed Vs), it is specified by the curve Lb as shown in FIG. Therefore, if this curve Lb is approximated by the straight line Lbb, the following equation 7 is obtained.

[0023]

## EQU00007 ## Gac.PHI. = B + C.Vs, where B and C are constants. As a result, the equation 6 is converted into the following equation 8.

[0024]

## EQU00008 ## Qac = (B + C.Vs) .0.24. (Trc-Tac) When the engine is idling, the cooling fan 50
Since only the air flow rate from a is calculated in Equation 7, Gac · Φ
May be considered constant.

Based on the above premise, the heat radiation amount Qrc from the condensed refrigerant in the condenser 50 is radiated to the air side, and thus Qrc = Qac. Therefore, the following equation 9 is obtained from both equations 5 and 8.

[0026]

## EQU9 ## Gr = A (B + C.Vs) (Trc-Tac) / (D-E.Trc) where A, D and E are constants. From the above, it was confirmed that the torque T can be determined.

In addition, when calculating the torque of the compressor 20 as described above, the inventors of the present invention calculate the torque as follows:
It was confirmed that it is necessary to delay the vehicle speed Vs for the following reasons. As described above, when the expression 7 is specified in relation to the vehicle speed Vs, when the vehicle speed Vs changes, the refrigerant flow rate Gr, the discharge volume Vc, and the torque T in the expressions 9, 2 and 1 are respectively expressed in the respective equations. Seems to change at the same time. In other words, in calculating the refrigerant flow rate Gr,
Heat dissipation amount Qrc from the condensed refrigerant in the condenser 50 and the condenser 5
On the premise that the heat radiation amount Qac from the air side of 0 is equal, the torque is calculated by assuming that the heat radiation amount Qrc can be known.

However, as a general rule, this is true in the steady state and not true in the transient state. Actually, it is observed that the change in the high-pressure side refrigerant pressure Ph, that is, the change in the torque T is delayed more than the change in the vehicle speed Vs, that is, the inflow outside air flow rate Gac due to the heat capacity of the condenser 50 and the like. That is, during the transition, the sum of the heat radiation amount Qac and the change in the heat capacity of the heat exchange portion of the condenser 50 is equal to the heat radiation amount Qrc. In other words, Qrc = Qac is satisfied only when the change in the heat capacity of the heat exchange section of the condenser 50 decreases to zero with the passage of time based on a certain delay system.

Therefore, during the transition, unless the delay is eliminated, the above torque calculation may not be performed accurately. However, in the vehicle, since the vehicle speed Vs can be known, it is possible to know the heat radiation amount Qac. Therefore, at the time of the transition as described above, it is possible to estimate Qrc from Qac by delaying the change of the vehicle speed Vs by a predetermined time constant. As a result, the refrigerant flow rate Gr, that is, the torque can be known from such estimation. Therefore, the present inventors have found that the vehicle speed Vs
On the other hand, by preliminarily providing a delay due to a predetermined time constant, it is possible to accurately estimate the refrigerant flow rate Gr and prevent a transient decrease in the accuracy of the torque calculation due to the heat capacity of the condenser 50 and the like. However, the time required for the high-pressure-side refrigerant pressure Ph to reach the value of the high-pressure-side refrigerant pressure Ph on the assumption that there is no delay in the change of the high-pressure-side refrigerant pressure Ph is selected as the time constant.

In the present embodiment configured as described above,
By closing the ignition switch IG, the vehicle is started while the engine is being started, and the microcomputer 130 is kept in an operating state. When an operation signal is generated from the operation switch SW in such a state, the microcomputer 130 starts executing the computer program in step 200 according to the flowcharts of FIGS. 3 and 4, and performs initialization processing in step 210. , The variable n is set to “1”, and the electromagnetic clutch 30
Output signal and air cooling fan 50a required for engagement of
Generates the fan output signal required to drive the.

Then, the electromagnetic clutch 30 is driven and engaged by the drive circuit 150 in response to the clutch output signal from the microcomputer 130, and the compressor 20 receives power from the engine via the belt mechanism and the electromagnetic clutch 30. Driven. Further, the air-cooling fan 50a is driven by the drive circuit 160 in response to a fan output signal from the microcomputer 130. Then, in the refrigeration cycle Rc, the compressor 20
The refrigerant in the pipe P1 is sucked and compressed and discharged as a high-temperature and high-pressure compressed refrigerant into the pipe P2.
With the cooling action of a, the compressed refrigerant from the pipe P2 is condensed and given to the inside of the pipe P3 as a condensed refrigerant.
Applies the liquid phase component in the condensed refrigerant from the pipe P3 to the pipe P4 as a circulating refrigerant, and the expansion valve 70 expands the refrigerant from the pipe P4 according to the temperature of the refrigerant in the pipe P1 to pass the pipe P5 through the evaporator. 40, and an evaporator 40
Cools the incoming air stream in response to the evaporating action of the incoming refrigerant.

After the arithmetic processing in step 210, the microcomputer 130 executes A-
The value of the outside air temperature digital signal (hereinafter referred to as the outside air temperature Tac) and the value of the refrigerant temperature digital signal (hereinafter referred to as the condensed refrigerant temperature Trc) are input from the D converter 120, and in step 220a, from the waveform shaper 110a. The rotational speed Nc of the compressor 20 is calculated according to each rotational speed shaping pulse of the waveform shaping device 110b.
The actual vehicle speed V of the vehicle according to each vehicle speed shaping pulse from
Calculate s. After that, the microcomputer 130
However, in the next step 220c, it waits for a predetermined time Time. However, the predetermined time period Time corresponds to the time constant and is stored in the ROM of the microcomputer 130 in advance.

When the waiting time at step 220c has elapsed, the microcomputer 130 causes the microcomputer to proceed to step 23.
0, the outside air temperature Tac and the condensing refrigerant temperature Trc in step 220 and step 2
The refrigerant flow rate Gr (kg / hour) of the refrigeration cycle Rc is calculated in accordance with the vehicle speed Vs at 20b, and step 240
Then, the discharge volume Vc (cc) of the compressed refrigerant of the compressor 20 is calculated according to the same calculated refrigerant flow rate Gr and the rotation speed Nc in step 220a based on the above-mentioned equation 2, and in step 250, the next number is calculated. Based on 10, the high pressure side refrigerant pressure Ph of the refrigeration cycle Rc is calculated according to the condensed refrigerant temperature Trc in step 220.

[0034]

## EQU10 ## Ph = f (Trc) However, this equation 10 is stored in advance in the ROM of the microcomputer 130 together with the equations 9 and 2.

At the present stage, if the calculated discharge volume Vc is equal to or larger than the maximum discharge volume Vcm of the compressor 20, the microcomputer 130 determines "NO" in step 260, and in step 260a, the following equation 11 Based on the high pressure side refrigerant pressure Ph in step 250, the compressor 20
The torque Ta of is calculated.

[0036]

[Equation 11]

On the other hand, if the calculated discharge volume Vc is smaller than the maximum discharge volume Vcm of the compressor 20, the microcomputer 130 determines "YES" in step 260, and in step 260b, based on the following equation 12. The torque Tb of the compressor 20 is calculated according to the high pressure side refrigerant pressure Ph in step 250.

[0038]

[Equation 12]

However, in the equation 11, T = Ta in the equation 1.
And Vc = Vcm. The number 12 is
In Formula 1, it can be obtained by setting T = Tb. Also, the number 1
The values 1 and 12 and the maximum discharge volume Vcm are stored in advance in the ROM of the microcomputer 130.

Step 260a or 260 as described above.
When the calculation processing in b is completed, the microcomputer 1
After step 260a, 30 sets torque Ta to Tn in step 260c, and after step 260b sets torque Tb to Tn in step 260b. At this time, since the vehicle is running, the engine rotation speed is 600 (r.p.m.) to 700 (r.p.m.).
p. m. Not in). Therefore, the microcomputer 1
30 determines in step 270 to be "NO" in relation to the rotation speed Nc in step 220a, and advances the computer program to step 270b. Then, the microcomputer 130 causes the step 270b.
At, the difference (Tn-Tn-1) between the latest torque Tn and the torque Tn-1 calculated one cycle before is set as the torque difference ΔT.

After that, the microcomputer 130
In step 270c, the drive voltage Vn is calculated according to the drive voltage Vn-1 calculated one cycle before based on the following equation 13 and the torque difference ΔT in step 270b.

[0042]

[Mathematical formula-see original document] Vn = Vn-1 + a * [Delta] T However, in the equation 13, a represents a constant. Also, the number 13
Are stored in advance in the ROM of the microcomputer 130.

Then, the microcomputer 130
However, in step 290, the drive voltage Vn in step 270c is generated as the opening degree output signal, and in response thereto, the drive circuit 140 drives the idle adjustment valve 10b in the drive voltage Vn.
Open to the target opening corresponding to n. Therefore, the bypass amount of the air flow passing through the bypass conduit 10c from the upstream side to the downstream side of the throttle valve 10a is adjusted by the opening degree of the idle adjusting valve 10b. At this time, the throttle valve 1 in the intake pipe 10
The air flow rate through 0a is adjusted according to the depression amount of the throttle valve 10a. After the calculation in step 290, the microcomputer 130 causes the step 290
At a, n = n + 1 is updated and the computer program is returned to step 220.

In the arithmetic processing state in which the determination of "NO" is repeated in step 270 while the vehicle is traveling as described above, the refrigerant flow rate Gr and the volume Vc are calculated based on the equations 2 and 9-12. And the torque Ta or the torque Tb are repeatedly calculated through the calculation of the high pressure refrigerant pressure Ph. In such a case, after the vehicle speed Vs is calculated in step 220b, the refrigerant flow rate Gr, the volume Vc, the high pressure refrigerant pressure Ph, and the torque Ta or the torque Tb are calculated after waiting for a predetermined time Time. Then, the microcomputer 130
However, in step 270b, the difference between the preceding value of the torque Ta (or the torque Tb) and the latest value is repeatedly calculated as the torque difference ΔT, and in step 270c, the drive voltage Vn-1 and Drive voltage Vn according to torque difference ΔT
Is repeatedly calculated, and in step 290, the drive voltage Vn
Is generated as an opening degree output signal. As can be easily understood from the equation 13, when the condition of Vc <Vcm is satisfied, Tb
Is determined to change in proportion to the change in Vc. In other words, the drive voltage Vn is repeatedly determined based on the equation 13 with the latest torque difference ΔT.

When the vehicle is stopped and the engine is left in the idling state in such a state, the microcomputer 130 determines in step 270 as "YES" based on the current rotational speed Nc in step 220a. To do. Then, in step 270a, the microcomputer 130 changes the target rotation speed Nco of the compressor 20 to the rotation speed N in step 220a.
c is subtracted, and the subtraction result (Nco-Nc) is used as the deviation En.
And set. However, the target rotation speed Nco is stored in the ROM of the microcomputer 130 in advance.

Next, the microcomputer 130 determines "NO" based on n ≠ 1 at step 280, and at step 280b based on the following equation 14, step 2
Deviation En at 70a, deviation En-1 preceding this,
And the driving voltage Vn-1 ("NO" in step 270).
Immediately after "YES", the drive voltage Vn is calculated according to the drive voltage calculated in step 270c one cycle before.

[0047]

Vn = Vn-1 + Kp (En-En-1) + ([theta] / Ti) * En where Kp, [theta] and Ti each represent a control constant. Further, the number 14 is the RO of the microcomputer 130.
It is stored in M in advance.

When the calculation process in step 280b is completed, the microcomputer 130 causes the step 29
At 0, the drive voltage Vn in step 280b is generated as an opening degree output signal, and in response to this, the drive circuit 140
However, the idle adjustment valve 10b is opened to the target opening corresponding to the drive voltage Vn. Therefore, the bypass amount of the air flow passing through the bypass conduit 10c from the upstream side to the downstream side of the throttle valve 10a is adjusted by the target opening degree of the idle adjusting valve 10b to maintain the idling state of the engine. It should be noted that the microcomputer 130 executes n in step 290a.
= N + 1 is updated. And the microcomputer 1
While the determination of step 270 is "YES", the unit 30 repeats the above-described operation while adding and updating n for each cycle.

As described above, when the vehicle is driven, the execution of the computer program is repeated under the repeated determination of "NO" in step 270. That is, in the repeated state of execution of this computer program, step 230 to step 250
, The calculation of the refrigerant flow rate Gr based on the equation 9, the calculation of the volume Vc based on the equation 2 and the calculation of the high pressure refrigerant pressure Ph based on the equation 10 are repeated, and step 260a (or step 260a (or Step 260
Torque Ta based on equation 11 (or equation 12) in b)
The calculation of (or torque Tb) is repeated. Therefore, the torque Ta in step 260a (or step 26
Since the torque Tb) at 0b is accurately calculated in consideration of not only the high-pressure refrigerant pressure Ph but also the change in the volume Vc of the compressor 20, accurate torque calculation can be easily performed and the volume of the compressor 20 and The special capacity sensor and torque sensor required for torque detection are unnecessary. In such cases,
The refrigerant flow rate Gr, the volume Vc, the high-pressure side refrigerant pressure Ph, and the torque Ta or the torque Tb are calculated after waiting a predetermined time Time after the vehicle speed Vs is calculated in step 220b. Therefore, the torque calculation is performed in conformity with the delay of the change in the high-pressure side refrigerant pressure Ph due to the heat capacity of the condenser 50 and the like, and as a result, the calculation accuracy of the torque of the compressor 20 can be maintained high. Further, since the drive voltage Vn is repeatedly calculated according to the set torque in step 260c or 260d, when the engine is placed in the idling state again, the drive voltage calculated immediately before the determination of "YES" in step 270 is made. Vn-1 (that is, step 27
Step 2 based on the driving voltage Vn) calculated at 0c
The drive voltage Vn is calculated at 80b to generate an opening degree output signal at step 290, and the opening degree of the idle adjusting valve 10b is adjusted based on the value of the opening degree output signal. Therefore, the rotational speed of the engine in the idling state again can be accurately and favorably maintained under the torque in the proper range.

In other words, even when the capacity of the compressor 20 increases as the load of the air conditioner increases while the vehicle is running as described above, this capacity increase, that is, the torque and the drive voltage are increased. Increase Vn in step 260
a (or 260b) and step 270c are repeatedly calculated, and thereafter, when the engine is placed in the idling state again, the drive voltage Vn is calculated at step 280b with the increased drive voltage to generate the opening output signal. Therefore, the opening degree of the idle adjusting valve 10b is adjusted according to the increased load of the air conditioner, that is, the drive voltage Vn commensurate with the increased torque of the compressor 20.

Therefore, even when the engine is idling again as described above, the output of the engine can be secured by the increasing torque of the compressor 20 immediately before that, that is, the increasing flow rate of the bypass air flow of the idle adjusting valve 10b.
It is possible to smoothly maintain the engine's second idle state without a drop in the rotation speed. Further, as described above, the torque calculation is performed with a delay due to the time constant with respect to the vehicle speed Vs. Therefore, regardless of the heat capacity of the condenser 50 and the like, the torque is accurate and the engine idling state is always good. Can be maintained.

It should be noted that when the vehicle is placed in an idling state before the vehicle starts traveling, the microcomputer 130
However, with the start of its operation,
Without making a determination of “NO” in step 270,
When proceeding to step 270a and thereafter, the microcomputer 130 initially sets (Nco-Nc) to the deviation E1 in step 270a, determines "YES" in step 280, and Step 280
In a, set E0 = E1 = 0 and V0 = V00
Is set and the arithmetic processing in step 280b is performed. The process of step 280a is an initial setting for appropriately performing the calculation process of step 280b for the first time.

Further, in carrying out the present invention, unlike the above embodiment, the rotation speed N in step 220a is
c is the value when the engine is idling, for example 85
It is also possible to specify 0 (r.p.m.) and then perform the arithmetic processing after step 230. Further, in carrying out the present invention, regarding the calculation of the heat radiation amount Qac by the equation 7 in the above-mentioned embodiment, instead of the condensed refrigerant temperature Trc,
The temperature of the refrigerant at the refrigerant outlet of the condenser 50 may be adopted.

Further, in the above embodiment, the condenser 50
In relation to Qac = Qrc, based on the refrigerant flow rate Gr
However, instead of this, the refrigerant flow rate Gr may be obtained as described below in relation to the evaporator 40. That is, the equation 15 showing the relationship between the heat radiation amount Qre of the evaporator 40 and the latent heat component Δie of the refrigerant.
Is expressed as follows, corresponding to equation 3.

[0055]

[Equation 15] Qre = Δie · Gr Further, the heat radiation amount Qae of the evaporator 40 is specified by the following Equation 16 corresponding to the Equation 6.

[0056]

[Equation 16] Qac = Gae · Φ · 0.24 (Tae−Tre) · k where Tae represents the intake air temperature of the evaporator 40. Moreover, Tre represents the refrigerant temperature in the evaporator 40 (or the refrigerant outlet temperature of the evaporator 40). Also, Gae / Φ
Is determined by the air flow of the blower of the air conditioner.
k is a constant and is “2”.

From the above, based on Qae = Qre, Equation 9
Equation 17 is established corresponding to.

[0058]

## EQU17 ## Gr = Gae.PHI..0.24 (Tae-Tre) .k / .DELTA.ie Note that the outside air temperature sensor 90 in the above embodiment is used as an intake air temperature sensor of the evaporator 40. The refrigerant temperature sensor 100 is used as a refrigerant temperature sensor for the evaporator 40. In such a case, instead of the refrigerant temperature sensor,
A post-evaporation sensor that detects the temperature of the outflow air flow from the evaporator 40 may be adopted.

Further, in the above embodiment, the change in the high pressure side refrigerant pressure Ph due to the heat capacity of the condenser 50 or the like with respect to the change in the vehicle speed Vs, that is, the change in the torque T is more than the change in the vehicle speed Vs, that is, the inflow outside air flow rate Gac. Although the example of coping with the delay has been described, the present invention is not limited to this, and instead of the vehicle speed Vs, the delay of the change in the torque T due to the heat capacity of the condenser 50 with respect to the change in the temperature and the air volume of the air side of the condenser 50 is delayed. The present invention may be applied and implemented to solve the problem.

In implementing the present invention, as shown in FIG. 6, the refrigerant temperature sensor 100 in the above embodiment may be supported by pressure contact with the bent portion of the condensing pipe 51 of the condenser 50 by the leaf spring 51a. .. Further, in carrying out the present invention, the discharge pressure of the compressor 20 may be directly obtained by the pressure sensor without obtaining the high pressure side refrigerant pressure Ph by equation 10.

Further, in carrying out the present invention, in the above-described embodiment, the initial value of the idle control is given according to the torque immediately before the idling state, and the idle rotation speed according to the torque is given only as the initial value. The above description is based on the premise that the idle rotation speed can be stably controlled only by the feedback control based on the deviation En because the capacity change during idling is small and the torque fluctuation is small. Therefore, if the capacity changes rapidly and the torque changes even during idling, the torque may be calculated even during idling, and the idling rotation speed may be controlled according to the torque.

Further, in the above-mentioned embodiment, the example in which the present invention is applied to the idle speed control of the engine has been described, but the present invention is not limited to this and, for example, the present invention is applied to appropriately control the engaging force of the electromagnetic clutch 30. May be applied and implemented. Further, in the above embodiment, the compressor 20
Although the example in which the engine is adopted as the drive source of the above, the electric motor or the like in the electric vehicle may be adopted as the drive source of the compressor 20 instead.

In implementing the present invention, B1 + C1.Nc may be adopted instead of B + C.Vs described above. However, B1 = 950 and C1 = 0.35. Further, the wind speed of the outside airflow flowing into the condenser 50 may be detected by a wind speed sensor, and this detection timing may be used instead of the calculation timing of the vehicle speed Vs.

In implementing the present invention, the present invention may be applied to the delay of the torque calculation due to the heat capacity of the evaporator 40 with respect to the air blown from the blower.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to the description of the claims.

FIG. 2 is a block diagram showing an embodiment of the present invention.

FIG. 3 is a front part of a flowchart showing the operation of the microcomputer of FIG.

FIG. 4 is a latter part of the flowchart.

FIG. 5 is a graph showing a relationship between latent heat Δi and condensed refrigerant temperature Trc, and a graph showing a relationship between Gac · Φ and a flow velocity Vk of an external air flow and a vehicle speed Vs.

FIG. 6 is a diagram showing a modification of the mounting position of the refrigerant temperature sensor.

[Explanation of symbols]

Rc ... Refrigeration cycle, 20 ... Compressor, 40 ... Evaporator, 50 ... Condenser, 80a ... Rotation speed sensor, 80b ...
Vehicle speed sensor, 90 ... Outside air temperature sensor, 100 ... Refrigerant temperature sensor, 130 ... Microcomputer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Kinoshita 1-1, Showa-cho, Kariya city, Aichi Prefecture Nihon Denso Co., Ltd. (72) Inventor Yasuyuki Nishi, 1-1, Showa-cho, Kariya city, Aichi Nippondenso Within the corporation

Claims (1)

[Claims] 1. A system including a refrigeration cycle in which a refrigerant is circulated through a heat exchanger by a variable displacement compressor driven by a drive source such as a prime mover mounted on a vehicle, and a discharge pressure of the refrigerant from the compressor. A discharge pressure determining means for determining the change of the air side load condition by a transient delay time of the change of the heat exchange capacity caused by the heat capacity of the heat exchange part when the air side load condition of the heat exchanger changes. A heat exchange capacity determining means for determining the heat exchange capacity based on a change in the air side load condition when the delay time elapses, and the compressor according to the determined discharge pressure and the determined heat exchange capacity. And a torque calculation means for calculating the torque of the variable displacement compressor.