JP3092248B2 - Drive torque detection device for variable capacity compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive torque detector for detecting a drive torque of a variable displacement compressor which is provided in a cooling device such as an air conditioner of a vehicle and circulates a refrigerant through a condenser and an evaporator. Related to the device.

[0002]

2. Description of the Related Art Conventionally, in a vehicle equipped with a cooling device such as an air conditioner, the magnitude of the engine load by the cooling device is estimated based on whether the cooling device is operating or the high pressure side of the circulating refrigerant. By controlling the intake air amount (fuel supply amount) to the engine in the idling state according to the estimation result, the engine in the idling state is not rough idle or the engine stall (hereinafter simply referred to as engine stall). (See, for example, Japanese Patent Application Laid-Open No. 62-41951).

[0003]

When controlling the engine output in accordance with the operation of such a cooling device, it is originally desirable to detect the driving torque of the compressor in the cooling device. However, in the above-described conventional apparatus, since the driving torque of the compressor is not detected, the amount of intake air (fuel supply amount) to the engine in an idling state cannot be accurately controlled. In such a cooling device, a variable displacement compressor is often used. In particular, the driving torque of the variable displacement compressor is affected not only by the high pressure side of the refrigerant but also by the displacement. Therefore, the method of the related art cannot accurately control the intake air amount (fuel supply amount) to the idling engine. Therefore, the appearance of a device that can easily and accurately detect the driving torque of a variable displacement compressor has been desired. The present invention has been made to address the above-described problem, and an object of the present invention is to provide a variable displacement compressor drive torque detecting device that accurately detects the drive torque of a variable displacement compressor provided in a cooling device with a simple configuration. To provide.

[0004]

In order to achieve the above object, a structural feature of the present invention is that, as shown in FIG. 1, a refrigerant provided in a cooling device 1 is supplied through a condenser 1a and an evaporator 1b. A drive torque detecting device for detecting a drive torque of the variable displacement compressor 1c to be circulated; a capacity detecting means 2 for detecting a displacement of the variable displacement compressor 1c;
A high-pressure side pressure detecting means 3 for detecting the pressure of the refrigerant condensed by the condenser 1a; and a variable displacement compressor 1c based on a predetermined first arithmetic expression using the detected capacity and pressure.
And a driving torque of the variable capacity compressor 1c based on a predetermined second calculation formula using a first capacity calculating means 4 for calculating the driving torque of the variable capacity compressor 1c and a predetermined capacity representing the maximum capacity of the variable capacity compressor 1c and the detected pressure. And a torque for determining the smaller value of the drive torque of the first torque calculator 4 and the drive torque of the second torque calculator 5 as the drive torque of the variable displacement compressor 1c. And the decision means 6.

[0005]

In general, the driving torque of the variable displacement compressor in the cooling device increases as the heat load increases, and at the same time is determined by its capacity, the high pressure side and the low pressure side of the refrigerant. In this case, as shown in FIG. 7, until the capacity of the variable capacity compressor reaches the maximum (0 to 100%), the low pressure side pressure is constant, and the drive torque of the compressor changes its capacity and the high pressure side pressure. It changes linearly with this (see the solid line in FIG. 7). When the capacity of the variable capacity compressor reaches the maximum (100%), the capacity becomes constant, and the driving torque of the compressor changes linearly with a large change in the high pressure side and a small change in the low pressure side ( (See the broken line in FIG. 7).

[0006] Based on such a relationship, in the present invention configured as described above, the first torque calculating means 4 sets the capacity detection means as a main range until the capacity of the variable capacity compressor 1c reaches the maximum. The driving torque of the variable displacement compressor 1c is calculated based on the first calculation formula using the capacity detected by the pressure detection unit 2 and the pressure detected by the high pressure side pressure detection means. This variable capacity compressor 1c
Since the low-pressure side pressure is constant until the capacity of the motor reaches the maximum, the calculated drive torque becomes accurate. On the other hand, with the main range after the capacity of the variable capacity compressor 1c reaches the maximum, the second torque calculating means 5 uses the predetermined capacity representing the maximum capacity of the compressor 1c and the predetermined pressure to detect the predetermined capacity. The driving torque is calculated based on the second calculation expression. This variable capacity compressor 1
Even when the capacity of c reaches the maximum, the low-pressure side pressure changes but the change amount is small, so if the approximately middle value of the change range is selected as the low-pressure side pressure, the calculated driving torque is the actual driving torque. The result is a better approximation of the torque.

The torque determining means 6 determines the smaller one of the driving torques calculated by the first and second torque calculating means 4 and 5 as the driving torque of the variable displacement compressor 1c. The finally determined drive torque continuously changes according to the heat load, and does not include a large error even when the capacity of the variable displacement compressor 1c reaches the maximum.

[0008]

As can be understood from the above description of the operation,
According to the present invention, since the drive torque of the variable displacement compressor 1c is detected by executing the calculation based on the capacity of the variable displacement compressor 1c and the high pressure side pressure, the drive torque can be accurately detected with a simple configuration.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows a cooling device 10 constituting a part of an air conditioner of a vehicle and a fuel for adjusting a fuel supply amount to an engine EG. FIG. 2 is a block diagram showing a supply amount adjusting device 20 and an electric control device 30 to which the cooling device 10 and the fuel supply amount adjusting device 20 are electrically controlled while the drive torque detecting device of the present invention is applied.

The cooling device 10 includes a variable capacity compressor 11
It has. The variable displacement compressor 11 is selectively driven by the engine EG via the belt 12 and the electromagnetic clutch 13. At the time of driving, the variable displacement compressor 11 sucks the refrigerant in the low-pressure pipe P1 and sends it to the high-pressure pipe P2. The refrigerant is circulated through the condenser 14 and the evaporator 15. The condenser 14 is provided with a cooling fan 16, and the condenser 14 condenses the refrigerant by the air cooling action of the cooling fan 16. Further, a receiver 17 is interposed in the high-pressure pipe P2 downstream of the condenser 14. The receiver 17 separates the condensed refrigerant input through the high-pressure pipe P2 on the condenser 14 into a gas phase component and a liquid phase component, and outputs only this liquid phase component to the high-pressure pipe P2 on the evaporator 15 side. The evaporator 15 cools the airflow flowing into the vehicle cabin by its evaporating effect. The evaporator 15 is provided with an expansion valve 18 upstream and a temperature-sensitive cylinder 19 downstream. The temperature sensing tube 19 detects the temperature of the refrigerant output from the evaporator 15 and sets the opening of the expansion valve 18 according to the temperature. The valve 18 connects the high-pressure pipe P2 with the set opening. The refrigerant supplied via the air is expanded and supplied to the evaporator 15.

The fuel supply adjusting device 20 includes a throttle valve 22 provided in an intake pipe 21 and an idling adjusting valve 24 provided in a bypass 23 of the valve 22. The opening of the throttle valve 22 is changed in accordance with the amount of depression of the accelerator pedal. The opening directly adjusts the intake air amount in the non-idling state of the engine EG, and indirectly adjusts the amount of intake air. In this state, the amount of fuel supplied to engine EG and the amount of air-fuel mixture are adjusted. The opening degree of the idling adjustment valve 24 is electrically controlled to change the opening degree. According to the opening degree, the intake air amount in the idling state of the engine EG is directly adjusted, and indirectly the same. The fuel supply amount and the air-fuel mixture amount to the engine EG in the state are adjusted.

The electric control device 30 includes an outside air temperature sensor 31,
A rotation speed sensor 32, a high pressure side pressure sensor 33, a vehicle speed sensor 34, and an operation switch 35 are provided. The outside air temperature sensor 31 is provided between the condenser 14 and the front grill in the engine room, detects the temperature Tac of outside air flowing into the engine room from outside the vehicle and passing through the condenser 14, and detects the temperature Tac. Is output. The rotational speed sensor 32 is attached to the variable capacity compressor 11, detects the rotational speed Nc of the compressor 11, and detects the rotational speed Nc.
Is output. The high-pressure side pressure sensor 33 is attached to the high-pressure pipe P2 near the outlet of the receiver 17, detects the high-pressure side pressure Ph of the refrigerant, and outputs a detection signal representing the pressure Ph. The vehicle speed sensor 34 detects the vehicle speed U by measuring the rotation speed of the output shaft of the transmission, the rotation speed of the wheels, and the like, and outputs a detection signal representing the vehicle speed U. The operation switch 35 is a switch operated when operating the air conditioner.

The sensors 31 to 34 and the operation switch 35 are connected to a microcomputer 36. The microcomputer 36 stores a program corresponding to the flowcharts of FIGS. 3 and 4 in its internal ROM, and executes each of the drive circuits 37 to
The electromagnetic clutch 13, the cooling fan 16, and the idling adjustment valve 24 are controlled via 39. The drive circuits 37 and 38 control ON / OFF of the clutch 13 and the fan 16 depending on whether drive power is supplied to the electromagnetic clutch 13 and the cooling fan 16, respectively, and the drive circuit 39 drives to supply the idling adjustment valve 24. The opening of the valve 24 is controlled in proportion to the voltage. A battery BT is connected to the microcomputer 36 via an ignition switch IG.

Next, the operation of the embodiment configured as described above will be described. When the ignition switch IG is turned on, the engine EG is started and the microcomputer 36 starts operating. In this state, when the operation switch 35 is turned on, in response to the on operation,
The microcomputer 36 starts the execution of the program from step 50 in FIG. 3, executes the initial setting process in step 51, and continues to repeatedly execute the cycling process including steps 52 to 69 (FIGS. 3 and 4). In this initial setting process, the variable n is set to “1”,
An operation control signal is output to the drive circuits 37 and 38.

In response to the operation control signal, the driving circuit 3
7 supplies driving power to the electromagnetic clutch 13 and turns on the clutch 13, so that the rotational driving force from the engine EG is transmitted to the variable displacement compressor 11 via the belt 12 and the electromagnetic clutch 13, The compressor 11 starts operating. Further, the drive circuit 38 also supplies drive power to the cooling fan 16, so that the fan 16 also starts to rotate. As a result, the cooling device 10 starts to cool the air flowing into the vehicle compartment by the action of the refrigerant that is pumped by the variable capacity compressor 11 and circulates through the condenser 14, the receiver 17, the expansion valve 18, and the evaporator 15.

In the circulation process consisting of steps 52 to 69, first, at step 52, each sensor 31 to 34
From the outside air temperature Tac, the rotational speed Nc of the variable capacity compressor 11, the refrigerant high pressure side pressure Ph, and the vehicle speed U, respectively, are inputted, and the values Tac, Nc, Ph,
U is temporarily stored. Next, steps 53-60
Are executed, and thereafter, in step 61, it is determined whether or not the engine EG is in an idling state.
This determination process is performed based on the rotation speed Nc of the variable displacement compressor 11 (substantially equal to the rotation speed of the engine EG), and the rotation speed Nc falls within a predetermined rotation speed range, for example, within a range of 600 to 800 rpm. Is determined.

In this case, immediately after the ignition switch IG is turned on, "YE
S ", that is, it is determined that the engine EG is in the idling state, so the program proceeds to step 62 and subsequent steps. In this case, since the variable n has been set to “1” by the initial setting process in step 51, “YES” is determined in step 63 after the process in step 62, and the variable capacity is determined in step 64. Deviation En between target rotation speed Nco of compressor 11 and detected rotation speed Nc
The initial values E0 and E1 of (= Nco-Nc) are both set to "0", and the initial value V0 of the drive voltage Vn for the idling adjustment valve 24 is set to the predetermined voltage V00. Although the target rotation speed Nco is a predetermined value of about 700 rpm, it may be slightly different depending on the operation state of the engine EG by a process not shown (for example, when the engine EG is warmed up, etc.). (A value slightly larger than 700 rpm). The predetermined voltage V00 is set so that the rotation speed of the engine EG becomes the target rotation speed Nco when the opening of the idling adjustment valve 24 is adjusted by the same voltage V00 in a state where the throttle valve 22 is fully closed. This is a preset value.

After the processing of step 64, step 65
The driving voltage Vn is calculated by executing the calculation of the following equation (1).

[0019]

(Equation 1)

In the above equation 1, the coefficients Kp, θ, Ti are predetermined control constants. In this case, the deviation En
(= E1) and En-1 (= E0) are both "0" and the drive voltage Vn-1 (= V0) is the predetermined voltage V00, so the drive voltage Vn is set to the same predetermined voltage V00. . Then, at step 66, the control signal representing the drive voltage Vn is supplied to the drive circuit 3
9 is output. The drive circuit 39 outputs the drive voltage Vn to the idling adjustment valve 24 and controls the opening of the valve 24 in proportion to the voltage Vn (= V00).
The amount of intake air supplied to the intake pipe 21 via the bypass 23 is determined by the drive voltage Vn. As a result, air and fuel (air-fuel mixture) are supplied to the engine EG in an amount proportional to the drive voltage Vn, so that the output of the engine EG is controlled by the air-fuel mixture.

After the processing in step 66, step 67
Is added to the variable n, the program returns to step 52, and as long as the engine EG remains idling, the above-described circulation processing of steps 52 to 67 is continuously executed. In this circulating process, the variable n becomes larger than "1" by the process of the step 67, so that the determination of "NO" is continued at the step 63, and the idling adjustment valve is determined by the processes of the steps 62, 65 and 66. 24 is continuously controlled. In this case, at step 62, the following equation 2 is executed to calculate the deviation E between the target rotation speed Nco of the variable displacement compressor 11 and the current detected rotation speed Nc of the compressor 11:
In step 65, the value θ · En / Ti proportional to the deviation En is added to the drive voltage Vn−1 in the previous circulation process, and the drive voltage Vn is calculated. It is updated for each circulation process.

[0022]

## EQU2 ## Since the amount of air-fuel mixture to the engine EG is controlled in step 66 in proportion to the updated drive voltage Vn, the rotational speeds of the engine EG and the variable displacement compressor 11 are controlled. Is controlled to reach the target rotation speed Nco. Further, the term Kp · (En−En−1) in the above equation (1) controls the change curve in which the rotation speed of the variable displacement compressor 11 approaches the target rotation speed Nco so as to be smooth.

In such an idling state, when the accelerator pedal is depressed to open the throttle valve 22, the amount of fuel supplied to the engine EG (the amount of air-fuel mixture).
Increases, and the rotation speed of the engine EG increases. As a result, the rotation speed Nc of the variable displacement compressor 11 also increases, so that "NO" in step 61, that is, it is determined that the rotation speed Nc is not within the predetermined range (600 to 800 rpm), and the process proceeds to steps 68 and 69. And the torque deviation Δ
T and drive voltage Vn are calculated respectively,
The circulation process including steps 68, 69, 66, 67, and 52 to 61 is repeatedly executed. In the calculation processing of the torque deviation ΔT in step 68, the drive torque Tn of the variable displacement compressor 11 calculated by the processing in steps 53 to 60 is used. Next, the processing of steps 53 to 60 will be described.

First, in step 53, based on the high-pressure side pressure Ph input in the processing in step 52, the following equation (3) representing the relationship between the pressure Ph and the temperature Trc of the refrigerant condensed in the condenser 14 is calculated. , The condensed refrigerant temperature Trc is calculated.

[0025]

Trc = f (Ph) Next, at step 54, the calculated condensing refrigerant temperature T
rc and the outside air temperature T input by the processing in step 52.
Based on ac and the vehicle speed U, the flow rate Gr (Kg / hou) of the refrigerant circulating in the cooling
r) is calculated.

[0026]

(Equation 4)

In the above equation (4), the coefficients A, B, C,
D and E are preset values, for example, A = 0.2
4, B = 1200, C = 10, D = 38, E = 0.18.

Here, the theoretical basis of Equation 4 will be described. The inventors of the present application first consider that when the difference between the temperature on the outer surface of the condenser 14, that is, the outside air temperature Tac and the temperature Trc of the condensed refrigerant in the condenser 14, is large.
Paying attention to the general physical phenomenon that the refrigerant flow rate Gr is large because the heat radiation capacity of the condenser 14 is high and the refrigerant flow rate Gr is small because the heat radiation capacity of the condenser 14 is low when the difference between the two temperatures Tac and Trc is small, An attempt was made to find a relationship between the two temperatures Tac and Trc and the refrigerant flow rate Gr.

First, the heat release amount Qrc of the condensed refrigerant is considered by paying attention to the refrigerant in the condenser 14.
It is generally known that the refrigerant enthalpy Δi (Kcal / Kg) between the refrigerant inlet and the refrigerant outlet of the condenser 14 and the refrigerant flow rate Gr are represented by the following equation (5). is there.

[0030]

In this case, the refrigerant enthalpy Δi mainly corresponds to the latent heat of the condensed refrigerant, and if the type of refrigerant is specified, the condensed refrigerant temperature T
It is defined as a function of rc. For example, when the type of the refrigerant is selected as “R12”, it has been experimentally confirmed that the relationship between the enthalpy Δi and the condensed refrigerant temperature Trc is represented by a curve L in FIG. Was done. Here, if this curve L is approximated by a straight line La, the refrigerant enthalpy Δi is expressed by the following equation (6).

[0031]

Δi = D−E · Trc Therefore, the relational expression of the above expression (5) is transformed into a relational expression of the following expression (7).

[0032]

Qrc = (DE−Trc) · Gr where the coefficients D and E in the above equations 6 and 7 are D = 38 and E =
It is a constant of 0.18.

On the other hand, the outside air temperature Tac on the surface of the condenser 14
Considering the heat release amount Qac from the condenser 14 to the outside paying attention to the above, the heat release amount Qac is generally expressed by the following equation (8).

[0034]

Qac = A · Gac · Φ · (Trc−Tac) where Gac represents the flow rate (Kg / hour) of the outside air flowing into the condenser 14, and the value Φ represents the temperature efficiency of the condenser. Where A is a constant such that A = 0.24. Here, paying attention to the fact that the flow velocity of the external air flow on the outer surface of the condenser 14 corresponds to the vehicle speed U, it is experimentally shown that the relationship between the value Gac · Φ and the vehicle speed U is represented by a curve L in FIG. Was confirmed. here,
If the curve L is approximated by a straight line La, the value Gac · Φ becomes
Is represented by the following relational expression.

[0035]

Gac.PHI. = B + CU. Therefore, the relational expression of the above expression 8 is transformed into the following expression of the following expression 10.

[0036]

Qac = A · (B + CU) · (Trc−Tac) where the coefficients B and C in the above equation 10 are B = 1200 and C =
It is a constant of 10. When the engine EG is in the idling state, the value Gac · Φ may be regarded as being constant because only the air flow from the cooling fan 16 is provided.

Here, considering that the heat of the condensed refrigerant is radiated to the outside air via the condenser 14, the heat release amount Qrc of the condensed refrigerant defined by the above equation (7) is defined by the above equation (10). The amount of heat released from the condenser 14 to the outside is equal to Qac (Qrc =
Qac) is a matter of course, and the relational expression of the above formula 4 is derived from both the relational expressions of the above formulas 7 and 10. Therefore, it can be understood that the flow rate Gr of the refrigerant circulating in the cooling device 10 is calculated by executing the calculation of the above equation (4).

After the processing of step 54, step 55
, The capacity Vc of the variable displacement compressor 11 is calculated on the basis of the calculated refrigerant flow rate Gr and the rotation speed Nc input in the processing of the above step 52 by executing the calculation of the following equation (11).

[0039]

[Equation 11]

In this case, in the above equation 11, the value F is F = 9.2.
It is a constant of × 10 ^-4 . Thus, the capacity Vc of the variable capacity compressor 11 before the variable capacity compressor 11 reaches the maximum capacity Vcm is calculated.

In step 56, the capacity of the variable capacity compressor 11 is calculated based on the calculated capacity Vc and the high-pressure side pressure Ph input in step 52 by executing the following equation (12). Drive torque Ta for the compressor 11 when the capacity is Vc
Is calculated.

[0042]

(Equation 12)

The equation (12) is a well-known calculation formula. In this case, the values K and m are K = 2 × 10 ^-2 and m = 0.1
At the same time as the constant given as 23, the low-pressure side pressure Ps representing the pressure in the low-pressure pipe P1 is also a constant value (3 kg / c
m ² ). This is because in the region where the capacity of the variable capacity compressor 11 is variable, even if the heat load on the variable capacity compressor 11 changes, as shown by the solid line portion where the capacity percentage is 100% or less in FIG. This is because Ps is fixed at approximately 3 kg / cm ² .
Note that both the high-pressure side pressure Ph and the low-pressure side pressure Ps represent absolute pressures.

In step 57, the driving torque Tb for the variable capacity compressor 11 when the capacity of the variable capacity compressor 11 is the maximum capacity Vcm is calculated in the same manner as described above by executing the following equation (13). .

[0045]

(Equation 13)

In this case, the values K and m are the same as in the above case, but the low-pressure side pressure Ps is a fixed value (4 kg /
cm ² ). This is shown in FIG. 7 by the dashed line where the capacity percentage is 100% or more,
When the capacity of the variable capacity compressor 11 reaches the maximum capacity Vcm, the low pressure side pressure Ps changes to ³ to 5 kg / cm ² as the heat load on the compressor 11 increases. Because it was determined.

After the calculation of the two driving torques Ta and Tb in steps 56 and 57, the driving torques Ta and Tb are compared in step 58. In this case, if the drive torque Ta in the variable capacity region is equal to or smaller than the drive torque Tb in the maximum capacity, the drive torque Tn in the current circulation process is changed to the drive torque in step 59 based on the determination of “YES” in step 58. It is set to Ta. If the drive torque Tb is smaller than the drive torque Ta, the drive torque Tn in the current circulation process is set to the drive torque Tb in step 60 based on the determination of “NO” in step 58.

As described above, in steps 56 and 57, the driving torque Ta in the variable capacity region and the driving torque Tb in the maximum capacity are calculated, and the steps 58 to 6 are performed.
The reason why the minimum value of the two drive torques Ta and Tb is adopted as the drive torque Tn by the processing of 0 is that the drive torque Tn after the variable capacity compressor 11 reaches the maximum capacity Vcm is calculated as accurately as possible. It is. That is, after the variable capacity compressor 11 reaches the maximum capacity Vcm, the drive torque Tn for the variable capacity compressor 11 is increased.
Is to change the low pressure side pressure Ps from 3 to 5 kg / cm ² ,
FIG. 7 shows an increase in the heat load on the compressor 11.
The drive torque Tn is calculated as a value that changes as shown by the solid line in FIG. 7 by a simple calculation in which the low-pressure side pressure Ps is fixed, and the same torque Tn is calculated by the low-pressure side pressure Ps. This is for better approximation when it changes.

After calculating the driving torque Tn, the program proceeds to step 61 and subsequent steps. In this case, as described above, the engine EG is in the non-idling state, and “NO” is determined in Step 61, and Step 68,
69 is executed. In step 68, the torque deviation ΔT is calculated by executing the following equation 14 based on the driving torque Tn calculated in the current circulation processing and the driving torque Tn-1 calculated in the previous circulation processing. You.

[0050]

ΔT = Tn−Tn−1 Note that the previous drive torque Tn−1 is temporarily stored in steps 59 and 60 during the previous circulation process.

Next, at step 69, a new drive voltage Vn is calculated by executing the following equation (15) based on the drive voltage Vn-1 calculated in the previous circulation process and the calculated torque deviation ΔT. Is done.

[0052]

Vn = Vn-1 + a..DELTA.T In this case, the coefficient a is a predetermined constant.
The drive voltage Vn-1 is temporarily stored in step 69 of the previous circulation process.

After the calculation of the drive voltage Vn in step 69, a control signal representing the drive voltage Vn is output to the drive circuit 39 by the processing in step 66, and the opening of the idling adjustment valve 24 is reduced by the operation of the circuit 39. It is controlled in proportion to the drive voltage Vn. In this case, the previously calculated driving torque T
The change in the drive torque Tn calculated this time with respect to n-1 is calculated as a torque deviation ΔT, and a value a · ΔT proportional to the torque deviation ΔT is added to the previous drive voltage Vn-1 to obtain the drive voltage Vn Are sequentially updated. Thereby, even if the engine EG is in the non-idling state,
The opening of the idling adjustment valve 24 is set to a value necessary to obtain the current drive torque Tn. However, in this case, since the throttle valve 22 is in the open state, the adjustment of the opening degree of the idling adjustment valve 24 does not directly affect the rotation speed and output of the engine EG.

In such a non-idling state, the depression of the accelerator pedal is released and the throttle valve 2
When 2 is closed, the rotation speed of the engine EG decreases, and the engine EG enters an idling state. This allows
Again, "YES" is determined in step 61, and the processing of steps 62, 63, 65 to 67 is repeatedly executed, and the intake pipe 21 is bypassed through the bypass passage 23.
In addition, the amount of intake air and the amount of fuel (air-fuel mixture) supplied to the engine EG are proportional to the drive voltage Vn calculated by the processing of steps 62 and 65. However, in this case, unlike the start of the engine EG, the calculation of the above equation (1) executed in step 65 is calculated in step 69 when the engine EG is in the non-idling state. The drive voltage Vn-1 is used as an initial value, and the drive voltage Vn is updated while taking into account the deviation En between the target rotation speed Nco and the detected rotation speed Nc.

Therefore, according to the above embodiment, immediately after the engine EG changes to the idling state, according to the drive torque Tn-1 of the variable displacement compressor 11 when the engine EG is in the non-idling state, The amount of air and the amount of fuel (air-fuel mixture) to the engine EG are controlled. As a result, regardless of the state where the engine EG changes from the non-idling state to the idling state and the cooling capacity of the cooling device when the engine EG is in the non-idling state, the air amount and the fuel amount necessary and sufficient for the engine EG are sufficient. (Air-fuel mixture) is supplied, and the engine EG is prevented from becoming idle, stalling, or rotating at an excessive rotation speed due to fluctuations in the load of the cooling device. Can be maintained.

In this case, the drive torque of the variable capacity compressor 11 in the non-idling state is changed by the temperature Tac of the outside air flowing into the condenser 14 from the outside, the rotation speed Nc of the variable capacity compressor 11, and the high pressure side pressure of the circulating refrigerant. Since the calculation can be performed using the relatively easy-to-detect physical quantities Ph and the vehicle speed U, the drive torques Ta and Tb of the variable displacement compressor 11 can be detected with a simple configuration, and the amount of air-fuel mixture to the engine EG in the idling state can be controlled. . Further, the capacity V of the variable capacity compressor 11
Even in a region where c reaches the maximum capacity Vcm and the low pressure side pressure Ps changes, the execution of the above equation (13) using the median of the change range as the low pressure side pressure Ps actually causes the broken line in FIG. The driving torque that changes in this manner is approximated as shown by the solid line in FIG. 7, so that the driving torque Tb can be calculated accurately. Further, the minimum value of the calculated drive torque Ta before the variable capacity compressor 11 reaches the maximum capacity Vcm and the calculated drive torque Tb after the variable capacity compressor 11 reaches the maximum capacity Vcm is determined as the final drive torque Tn. Therefore, the torque Tn can be continuously changed.

In the above embodiment, the condensing refrigerant temperature Trc is calculated from the detected high-pressure side pressure Ph. However, since the high-pressure side pressure Ph and the condensing refrigerant temperature Trc have a one-to-one relationship, Instead of detecting the high-pressure side pressure Ph, the condensed refrigerant temperature Trc is detected, and the detected condensed refrigerant temperature Trc is detected.
The high pressure side pressure Ph may be calculated based on rc. In this case, the outlet part in the condenser 14 or the condenser 1
A temperature sensor is provided in the high-pressure pipe P2 connected to the refrigerant pipe 4, and the temperature of the refrigerant directly detected by the sensor is set to the condensing refrigerant temperature T.
Good to use as rc. Further, even if the temperature of the refrigerant is not directly detected as described above, as shown in FIG.
A temperature sensor 42 is pressed against the bent portion of the condensing pipe 14a by a leaf spring 41, and the surface temperature of the condensing pipe 14a detected by the sensor 42 can be used as the condensing refrigerant temperature Trc.

Further, the high pressure side pressure Ph, the outside air temperature Tac, the rotation speed Nc, and the vehicle speed U are detected, and the condensed refrigerant temperature Trc calculated from the detected high pressure side pressure Ph is calculated as follows:
The detected outside air temperature Tac, rotation speed Nc and vehicle speed U
Instead of calculating the capacity Vc based on the arithmetic expressions of the above equations (3), (4) and (11), the actual capacity Vrc of the variable capacity compressor 11 is directly detected (for example, the variable capacity compressor 11 of a swash plate type). If the inclination angle of the swash plate is detected), the drive torque Ta may be calculated using the detected actual capacity Vrc as the capacity Vc of the above equation (12). According to this, the detection of the outside air temperature Tac and the vehicle speed U and the calculation of the condensed refrigerant temperature Trc in the above embodiment become unnecessary.

When calculating the driving torques Ta and Tb based on the arithmetic expressions of the equations (12) and (13), the accuracy is somewhat deteriorated, but only the capacity Vc is treated as a variable with the high-pressure side pressure Ph being a constant value. You may.

In the above embodiment, the condenser 14
Although the refrigerant flow rate Gr is calculated by focusing on the heat exchange of the above, the refrigerant flow rate Gr may be calculated by focusing on the heat exchange of the evaporator 15 instead. That is, the relationship between the heat release amount Qre of the refrigerant in the evaporator 15 and the refrigerant enthalpy (the latent heat component of the refrigerant) Δie is represented by the following Expression 16 corresponding to Expression 5 in the above embodiment.

[0061]

Qre = Δie · Gr Further, the heat release amount Qae to the outside of the evaporator 15 is expressed as in the following Expression 17, corresponding to Expression 8 in the above embodiment.

[0062]

In this case, the value Tae represents the intake air temperature of the evaporator 15, and the value Tre represents the refrigerant temperature in the evaporator 15 (or
Represents the refrigerant outlet temperature of the evaporator 15). Also, the value G
ae · Φ is determined by the air volume of the air conditioner blower. The coefficient K is a constant of about “2”, and the coefficient A is a constant “0.24” similar to the above embodiment.

In this case as well, since the heat radiation amount Qre of the refrigerant is equal to the heat radiation amount Qae to the outside of the evaporator 15,
The refrigerant flow rate Gr is represented by the following equation 18 corresponding to equation 4 in the above embodiment.

[0064]

(Equation 18)

In this case, the temperature of the intake air and the temperature of the refrigerant near the outlet in the evaporator 15 are detected from the outside to the evaporator 15 by a temperature sensor, and the detected temperatures are taken as the intake air temperature Tae and the refrigerant temperature Tre, respectively. You can use it. Further, when detecting the refrigerant temperature, the temperature of the outlet of the evaporator 15 or the temperature of the low-pressure pipe P1 downstream may be detected from the outside without directly detecting the temperature of the refrigerant. Further, the value Gae · Φ and the value Δie are, as in the case of the above embodiment,
From the experimental results, a value defined by a function of the air volume of the blower of the air conditioner and the refrigerant temperature Tre may be used.

In the above embodiment, the engine E
When G changes from the non-idling state to the idling state, the driving voltage Vn-1 corresponding to the driving torque of the variable capacity compressor in the non-idling state immediately before the idling state is set as the initial value of the driving voltage Vn in the non-idling state. Thus, the amount of air-fuel mixture to the engine EG in the idling state is controlled according to the drive voltage Vn. However, this is based on the premise that the idle rotation speed of the engine EG can be stably controlled only by the feedback control based on the target rotation speed Nco because the displacement of the variable displacement compressor 11 in the idling state is small and the fluctuation of the driving torque is small. Things
If the capacity of the variable capacity compressor 11 changes suddenly during idling and the driving torque changes, the torque is detected and the amount of air-fuel mixture supplied to the engine is controlled in accordance with the torque. You may.

In the above embodiment, the capacity Vc of the variable compressor 11 is calculated by executing the calculation of the above equation 11 using the detected rotation speed Nc.
In the case of this embodiment, the engine E is in the idling state.
Since the amount of fuel supplied to G is controlled, the detected rotational speed N
The same capacity Vc may be calculated by replacing c with the rotational speed of the engine EG in an idling state, for example, 700 rpm.

Further, in the above embodiment, the case where the drive torque detecting device for a variable displacement compressor according to the present invention is applied to a vehicle has been described. The invention can be applied to other devices.

[Brief description of the drawings]

FIG. 1 is a claim correspondence diagram corresponding to the configuration of the present invention described in the claims.

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

FIG. 3 is a flowchart corresponding to a part of a program executed by the microcomputer of FIG. 2;

4 is a flowchart corresponding to another part of the program executed by the microcomputer of FIG. 2;

FIG. 5 is a characteristic diagram showing a relationship between a condensing refrigerant temperature Trc and a refrigerant enthalpy Δi.

FIG. 6 is a characteristic diagram showing a relationship between a vehicle speed U and a value Gac · Φ.

FIG. 7 is a characteristic diagram showing a relationship between a heat load and a driving torque for a variable capacity compressor.

FIG. 8 is a schematic diagram showing a specific example of a refrigerant temperature sensor.

[Explanation of symbols]

EG engine, 10 cooling device, 11 variable capacity compressor, 14 condenser, 15 evaporator, 20
Fuel supply control device, 24 ... idling adjustment valve,
Reference numeral 30 denotes an electric control device, 31 denotes an outside air temperature sensor, 32 denotes a rotation speed sensor, 33 denotes a high pressure side pressure sensor, 34 denotes a vehicle speed sensor, and 36 denotes a microcomputer.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Kinoshita 1-1, Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. (56) References JP-A-64-60780 (JP, A) JP-A-2-2 248673 (JP, A) JP-A-56-85581 (JP, A) JP-A-2-27177 (JP, A) JP-A-2-1155582 (JP, A) JP-A-62-41951 (JP, A) Japanese Utility Model Application No. Sho 59-182059 (JP, U) Japanese Utility Model Application Hei 2-20792 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04B 49/00 F02D 29/04 F02D 45/00 364

Claims (1)

(57) [Claims] 1. A drive torque detecting device for detecting a drive torque of a variable displacement compressor provided in a cooling device and circulating a refrigerant through a condenser and an evaporator; A high pressure side pressure detecting means for detecting a pressure of the refrigerant condensed by the condenser; and a second calculating means for calculating a driving torque of the variable capacity compressor based on a first predetermined arithmetic expression using the detected capacity and pressure. 1 torque calculating means, and second torque calculating means for calculating a drive torque of the variable capacity compressor based on a predetermined second calculation formula using a predetermined capacity representing the maximum capacity of the variable capacity compressor and the detected pressure. A smaller value between the driving torque by the first torque calculating means and the driving torque by the second torque calculating means. Drive torque detecting device for a variable displacement compressor, characterized by being configured by the torque determining means for determining a driving torque of the variable capacity compressor.