JP4682904B2 - Compressor drive torque estimation device and compressor drive source control device. - Google Patents

Description

  The present invention relates to a compressor driving torque estimation device that estimates driving torque of a compressor, and a compressor driving source control device that controls the output of a compressor driving source.

  2. Description of the Related Art Conventionally, vehicles that employ a variable displacement compressor that obtains driving force from a vehicle engine are known as refrigerant compressors for vehicle air conditioners. In this type of vehicle, generally, the driving torque of the compressor is estimated, and the engine output is controlled based on the estimated driving torque so that the engine speed does not fluctuate even if the driving torque of the compressor changes. I have to.

For example, in Patent Document 1, the driving torque of the compressor is estimated based on a control signal for electrically controlling the discharge capacity changing mechanism of the variable capacity compressor from the outside, and the estimated driving torque is added. The output torque is controlled.
JP 2001-180261 A

  However, in the operation of the discharge capacity changing mechanism of the variable capacity compressor, a mechanical operation delay (response delay) occurs with respect to the change of the control signal. For this reason, when the driving torque is estimated based on the control signal as in Patent Document 1, for example, in a transient state in which the discharge capacity changes greatly immediately after the start of compression of the variable displacement compressor, the estimated driving torque and the actual driving torque are There is a large discrepancy between the drive torque and the drive torque.

  Therefore, the applicant of the present invention previously calculated in Japanese Patent Application No. 2004-293226 (hereinafter referred to as the prior application example) is calculated so as to gradually increase with the elapsed time after the compressor starts to compress the refrigerant. A compressor driving torque estimation method has been proposed in which the smaller value of the estimated driving torque and the second estimated driving torque calculated based on the compressor discharge refrigerant pressure is adopted as the estimated driving torque.

  In the estimation method of the prior application example, since the value of the first estimated driving torque is calculated to be smaller than the value of the second estimated driving torque in a transient state immediately after the start of compression, the first increasing torque gradually increases with the elapsed time. One estimated driving torque is adopted as the estimated driving torque. This suppresses an increase in the difference between the estimated drive torque and the actual drive torque in the transient state.

  By the way, the prior application example describes that the first estimated driving torque can be calculated based on the above-described capacity control signal. However, according to further examination by the present inventor, the first estimated driving torque can be calculated based on the capacity control signal. It has been found that even if one estimated driving torque is calculated, the deviation between the estimated driving torque and the actual driving torque cannot be completely prevented.

  The present invention has been made in view of the above points, and it is an object of the present invention to suppress a deviation between an estimated drive torque and an actual compressor drive torque in a transient state immediately after the start of compression of a variable capacity compressor.

  The present invention has been devised based on the following experimental findings. The present inventor investigated changes in actual driving torque immediately after the start of compression in a variable capacity compressor having the same configuration as that of the first embodiment described later. FIG. 6 shows the results of the investigation, in which the horizontal axis represents the elapsed time and the vertical axis represents the actual compressor driving torque.

  Further, in FIG. 6, the investigation results obtained by changing the discharge refrigerant pressure (Pd) and the suction side refrigerant pressure (Ps) at the start of compression of the compressor into three conditions are plotted. C1 (solid line) is Pd = 3.0 MPa, Ps = 0.5 MPa, condition C2 (two-dot chain line) is Pd = 3.0 MPa, Ps = 0.2 MPa, condition C3 (dashed line) is Pd = 1.5 MPa, Ps = 0.2 MPa.

  In FIG. 6, when the conditions 1 and 2 are compared, even if the discharge refrigerant pressure (Pd) is the same value, the variable displacement compressor (10) compresses when the suction side refrigerant pressure (Ps) increases. The response time (Tn) from the start to the time when the actual drive torque of the compressor starts increasing is shortened, and the degree of increase in torque per unit time (ΔTrk) after the response time (Tn) has elapsed is increased. I know that.

  Further, when the condition 2 and the condition 3 are compared, even if the suction side refrigerant pressure (Ps) is the same value, if the discharge refrigerant pressure (Pd) becomes high, the response time (Tn) becomes long, and the degree of increase in torque. It can be seen that (ΔTrk) is small.

  That is, since the response time (Tn) and the torque increase degree (ΔTrk) in the transient state change depending on the discharge refrigerant pressure (Pd) and the suction side refrigerant pressure (Ps) at the start of compression of the compressor, the compression in the transient state It was found that if the driving torque of the machine is estimated based on the discharge side pressure (Pd) and the suction side pressure (Ps), it is possible to estimate with high accuracy while suppressing the deviation from the actual driving torque.

  Furthermore, according to the above experimental results, the response time (Tn) is smaller when the high-low pressure ratio (Pd / Ps) between the discharge refrigerant pressure (Pd) and the suction-side refrigerant pressure (Ps) at the start of compression of the compressor is smaller. It has been found that the torque increases and the degree of increase in torque (ΔTrk) increases. In FIG. 6, the response times (Tn) in the conditions 1 to 3 are indicated by T1 to T3, respectively.

  Based on the above knowledge, the present invention is a compressor driving torque estimation device that estimates the driving torque of a variable displacement compressor (10) configured to be capable of changing the discharge capacity, and includes a variable displacement compressor ( 10) A discharge side detection means (125) for detecting a physical quantity related to the discharge side pressure, a variable displacement compressor (10), a suction side detection means (124) for detecting a physical quantity related to the suction side pressure, and a discharge side Based on the discharge side detection values (Pd, In) detected by the detection means (125) and the suction side detection values (Te, Ps) detected by the suction side detection means (124), the variable displacement compressor (10) is detected. Based on the first estimated driving torque calculating means (S41 to S45) for calculating the first estimated driving torque (TrkA) and the discharge side detection values (Pd, In), the second estimation of the variable displacement compressor (10). Drive torque (TrkB) The second estimated driving torque calculating means (S46) to be output, and the estimated driving torque determination that adopts a smaller value as the estimated driving torque (STrk) among the first estimated driving torque (TrkA) and the second estimated driving torque (TrkB). A compressor drive torque estimating device including means (S47 to S49) is a first feature.

  According to this, the first estimated driving torque calculation means (S41 to S45) calculates the first estimated driving torque (TrkA) based on the discharge side detection values (Pd, In) and the suction side detection values (Te, Ps). Since the first estimated drive torque (TrkA) is calculated, a highly accurate estimated value in which a deviation from the actual compressor drive torque in a transient state immediately after the compression of the variable displacement compressor (10) is suppressed is obtained. can do.

  Further, since the estimated drive torque determining means (S47 to S49) adopts a smaller value as the estimated drive torque (STrk) among the first estimated drive torque (TrkA) and the second estimated drive torque (TrkB), immediately after the start of compression. By adopting the first estimated driving torque (TrkA) in the transient state, the deviation between the estimated driving torque (STrk) and the actual compressor driving torque can be suppressed.

  In the compressor drive torque estimating device having the first feature, the first estimated drive torque calculating means (S41 to S45) increases the drive torque from when the variable displacement compressor (10) starts compression. The estimated response time (Ts) until the start is determined, and further, the first estimated drive torque calculating means (S41 to S45) is used when the variable displacement compressor (10) starts the compression. When the elapsed time (T) is less than the estimated response time (Ts), the first estimated driving torque (TrkA) is set to 0 N · m. When the elapsed time (T) is equal to or longer than the estimated response time (Ts), the first The estimated driving torque (TrkA) may be calculated so as to gradually increase as the elapsed time (T) increases.

  According to this, when the first estimated drive torque calculating means (S41 to S45) calculates the estimated response time (Ts) and the elapsed time (T) is less than the estimated response time (Ts), the first estimated drive time is calculated. Since the torque is set to 0 N · m, the first estimated drive torque (TrkA) is a response time from when the variable displacement compressor (10) starts compression until the actual drive torque of the compressor starts to increase. (Tn) is also a highly accurate estimated value that takes into account.

  Further, when the elapsed time (T) is equal to or longer than the estimated response time (Ts), the first estimated driving torque (TrkA) is gradually increased from 0 N · m as the elapsed time (T) increases. In the transient state, the first estimated driving torque (TrkA) is reliably smaller than the second estimated driving torque (TrkB).

  As a result, the first estimated drive torque (TrkA) is reliably adopted as the estimated drive torque (STrk) in the transient state immediately after the compression of the variable displacement compressor (10) starts, so that the estimated drive torque (STrk) is further increased. ) And the actual drive torque of the compressor can be suppressed.

  In the compressor drive torque estimating device having the first feature described above, the first estimated drive torque calculating means (S41 to S45) is a discharge-side detection value (Pd) at the start of compression of the variable displacement compressor (10). , In) and the estimated response time (Ts) may be determined based on the suction side detection values (Te, Ps). According to this, as described above with reference to FIG. 6, the estimated response time (Ts) can be appropriately estimated.

  In the compressor drive torque estimating device having the first feature described above, the first estimated drive torque calculating means (S41 to S45) is a discharge-side detection value (Pd) at the start of compression of the variable displacement compressor (10). , In) and the suction side detection values (Te, Ps), the degree of increase (ΔTrkA) for gradually increasing the first estimated drive torque (TrkA) may be determined. According to this, as described above with reference to FIG. 6, the degree of increase (ΔTrkA) can be appropriately estimated.

  In the compressor driving torque estimating device having the first feature described above, the estimated driving torque determining means (S47 to S49) is configured to output the second estimated driving torque (S) when the elapsed time (T) is less than a predetermined reference time. The first estimated driving torque (TrkA) may be adopted as the estimated driving torque (STrk) in preference to TrkB).

  According to this, regardless of the magnitude of the first estimated driving torque (TrkA) and the second estimated driving torque (TrkB), when the elapsed time (T) is less than a predetermined reference time, the first estimated driving torque ( TrkA) is adopted as the estimated driving torque (STrk). Therefore, in the transient state at the start of compression, the first estimated driving torque (TrkA) is more reliably adopted as the estimated driving torque (STrk).

  In the compressor drive torque estimating device having the first feature described above, the discharge capacity of the variable displacement compressor (10) is changed by an electrical control signal (In) from the outside. The discharge side detection value may be the control signal (In). According to this, since the control signal (In) is an electrical signal, it can be easily detected.

  In the present invention, the compressor drive torque estimating device having the first feature described above is provided, and the variable displacement compressor (10) is driven based on the estimated drive torque (STrk) estimated by the compression drive torque estimating device. A compressor drive source control device that controls the output of a drive source that applies force is a second feature.

  According to this, since the highly accurate estimated driving torque (STrk) in which the deviation from the actual driving torque of the compressor is suppressed can be estimated by the compressor driving torque estimating device of the first feature, for example, estimated driving By controlling the output torque of the drive source so as to increase the amount of torque (STrk), the rotational speed of the drive source can be stabilized.

  In the compressor drive source control device according to the second feature, specifically, the variable displacement compressor may be mounted on a vehicle air conditioner, and the drive source may be a vehicle engine.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. In this embodiment, the present invention is applied to an idle speed control device for a vehicle. The vehicle of the present embodiment employs a variable displacement compressor 10 that obtains driving force from a vehicle running engine as a refrigerant compressor of a vehicle air conditioner, and the idle speed control device is a variable displacement compressor that will be described later. The engine speed is controlled based on the estimated drive torque STrk of the compressor 10.

  First, FIG. 1 is an overall configuration diagram relating to an idle speed control device of the present embodiment. The engine (not shown) has an intake pipe 20, and a throttle valve 20 a is disposed in the intake pipe 20. The throttle valve 20a adjusts the amount of intake air into the intake pipe 20 according to the opening degree associated with the depression of the accelerator pedal of the vehicle. As is well known, in the engine, the engine speed (output) is adjusted by the intake air amount and the fuel injection amount.

  The intake pipe 20 is provided with a bypass line 20b, and an idle adjustment valve 20c is disposed in the bypass line 20b. The idle adjustment valve 20c changes the bypass amount of the intake air flow from the upstream side to the downstream side of the throttle valve 20a according to the valve opening, and the engine idle speed is adjusted by the bypass amount of the intake air flow. .

  Further, the idle adjustment valve 20c is constituted by a known linear solenoid valve, and is electrically controlled by a drive voltage Visc output from an electric control unit to be described later, so that the valve opening degree is changed. ing.

  Next, the refrigeration cycle Rc that constitutes a part of the vehicle air conditioner is arranged in the engine room and includes the variable capacity compressor 10. In the refrigeration cycle Rc, the variable capacity compressor 10 sucks, compresses and discharges refrigerant downstream of the evaporator 70 (to be described later) via a pipe P1, and includes an electromagnetic clutch 30 and a belt mechanism (not shown). The driving force is transmitted from the engine via the motor and is rotated.

  Therefore, in the present embodiment, the driving source that gives the driving force to the variable displacement compressor 10 is an engine. In the present embodiment, a well-known swash plate type variable displacement compressor 10 that can continuously and variably control the discharge capacity by a control signal from the outside is adopted as the variable displacement compressor 10. The discharge capacity is the geometric volume of the working space where the refrigerant is sucked and compressed. Specifically, it is the cylinder volume between the top dead center and the bottom dead center of the piston stroke.

  The discharge capacity of the variable displacement compressor 10 is adjusted by changing the discharge capacity. The discharge capacity is changed by controlling the pressure Pc of a swash plate chamber (not shown) formed in the variable capacity compressor 10 and changing the inclination angle of the swash plate to change the stroke of the piston. .

  The pressure Pc in the swash plate chamber is obtained by changing the discharge refrigerant pressure Pd and the suction refrigerant pressure Ps by an electromagnetic capacity control valve 10a controlled by a control signal (control current In) output from the microcomputer 100 of the electric control unit described later. It is controlled by changing the rate of introduction into the swash plate chamber. As a result, the variable displacement compressor 10 can continuously change the discharge capacity in a range of approximately 0% to 100%.

  Since the variable displacement compressor 10 can continuously change the discharge capacity in a range of approximately 0% to 100%, the variable displacement compressor 10 can be reduced by reducing the discharge capacity to approximately 0%. Can be substantially deactivated. Accordingly, a clutchless configuration in which the rotary shaft of the variable displacement compressor 10 is always connected to the vehicle engine via the belt mechanism may be adopted.

  The discharge side of the variable capacity compressor 10 is connected to the inlet side of the condenser 40 via a pipe P2. The condenser 40 is disposed between the engine and a vehicle front grill (not shown) in the engine room, and the refrigerant discharged from the variable capacity compressor 10 and the outside air blown by the blower fan 40a. And a heat radiator that cools the refrigerant.

  The outlet side of the condenser 40 is connected to the inlet side of the gas-liquid separator 50 via the pipe P3. The gas-liquid separator 50 separates the refrigerant cooled by the condenser 40 into a gas-phase refrigerant and a liquid-phase refrigerant. The liquid-phase refrigerant outlet side of the gas-liquid separator 50 has an expansion valve via a pipe P4. 60. The expansion valve 60 expands the liquid-phase refrigerant separated by the gas-liquid separator 50 under reduced pressure, and adjusts the flow rate of the refrigerant flowing out from the outlet side of the expansion valve 60.

  Specifically, the expansion valve 60 has a temperature sensing cylinder 60a for detecting the refrigerant temperature in the pipe P1, and the temperature of the refrigerant (refrigerant in the pipe P1) sucked into the variable capacity compressor 10 is determined. The degree of superheat of the compressor suction side refrigerant is detected based on the pressure, and the valve opening is adjusted so that the degree of superheat becomes a predetermined value set in advance.

  The downstream side of the expansion valve 60 is connected to the evaporator 70 via a pipe P5. The evaporator 70 exchanges heat between the refrigerant decompressed and expanded by the expansion valve 60 and the blown air blown by the blower fan 70a, and the low-pressure refrigerant flowing into the evaporator 70 absorbs heat from the blown air and evaporates. This is a heat exchanger in which the blown air is cooled.

  The downstream side of the evaporator 70 is connected to the pipe P <b> 1, and the evaporated refrigerant flows into the variable capacity compressor 10 again. Thus, in the refrigeration cycle Rc, the refrigerant circulates in the order of the variable capacity compressor 10 → the condenser 40 → the gas-liquid separator 50 → the expansion valve 60 → the evaporator 70 → the variable capacity compressor 10. ing.

  Next, an outline of the electric control unit of the present embodiment will be described. The electric control unit includes a known microcomputer 100 including a CPU, a ROM, a RAM, and the like and peripheral circuits 110 and 131 to 133 thereof. The microcomputer 100 stores control programs for the air conditioning control devices 10a, 30, 70a, the idle adjustment valve 20c, and the like in its ROM, and performs various calculations and processes based on the control programs.

  Sensor detection signals are input from the air conditioning sensor groups 121 to 125 to the input side of the microcomputer 100 via the A / D converter 110 which is a peripheral circuit, and are further arranged near the instrument panel in the front part of the vehicle interior. An operation signal, a detection signal of the engine tachometer 126 for detecting the engine speed Ne, and the like are input from various air conditioning operation switches SW provided on the air conditioning operation panel.

  Specifically, the air conditioning sensor group includes an outside air sensor 121 that detects the outside air temperature Tam, an inside air sensor 122 that detects the inside air temperature Tr, a solar radiation sensor 123 that detects the amount of solar radiation Ts incident on the vehicle interior, and the evaporator 70. An evaporator temperature sensor 124 for detecting the evaporator blown air temperature Te, a high pressure sensor 125 for detecting the discharge refrigerant pressure Pd discharged from the variable capacity compressor 10 and the like are provided.

  In the present embodiment, the high pressure sensor 125 serves as a discharge side detection unit that detects a physical quantity related to the discharge pressure of the variable capacity compressor 10, and the discharge refrigerant pressure Pd serves as a discharge side detection value. The high-pressure sensor 125 is generally provided for detecting a pressure abnormality in the refrigeration cycle Rc, and therefore it is necessary to newly install a dedicated detection means for detecting a physical quantity related to the discharge pressure. Absent.

  Further, in the present embodiment, the evaporator temperature sensor 124 serves as suction side detection means for detecting a physical quantity related to the suction pressure of the variable capacity compressor 10, and the evaporator blowout air temperature Te serves as the suction side detection value. This is because the evaporator blowing air temperature Te is substantially equal to the refrigerant evaporation temperature in the evaporator 70, and therefore, the refrigerant evaporation pressure in the evaporator 70 (that is, the suction pressure of the variable capacity compressor 10) can be determined by this refrigerant evaporation temperature. .

  As the various air conditioning operation switches SW provided on the air conditioning operation panel, an air conditioner switch that outputs an operation command signal of the variable capacity compressor 10, a blow mode switch that sets a blow mode, an auto switch that outputs a command signal of an air conditioning automatic control state, A temperature setting switch or the like serving as temperature setting means for setting the passenger compartment temperature is provided.

  Next, the electromagnetic clutch 30, the blower fan 70a of the evaporator 70, the idle adjustment valve 20c, and the like are connected to the output side of the microcomputer 100 via drive circuits 131 to 133 for driving various actuators which are peripheral circuits. Furthermore, an electromagnetic capacity control valve 10a of the variable capacity compressor 10 is connected. The operations of these various actuators 10 a, 30, 70 a, and 20 c are controlled by output signals from the microcomputer 100.

  Next, control processing executed by the microcomputer 100 in the present embodiment will be described based on the flowcharts of FIGS. This control routine is started in response to an operation signal from the operation signal switch SW in a state where an ignition switch of a vehicle engine (not shown) is turned on and power is supplied from the battery B to the microcomputer 100.

  First, in step S1 in FIG. 2, initialization of flags, timers, and the like is performed. As the flag, there is an activation determination flag Tflg or the like indicating whether or not the variable capacity compressor 10 to be described later has just been activated, and Tflg = 0 is set in Step 1. The timer is built in the microcomputer 100. In this embodiment, the timer is an elapsed time measuring unit that measures an elapsed time T from when the variable displacement compressor 10 starts compression.

  Next, in step S2, an operation signal of the air conditioning operation switch SW and detection signals of the air conditioning sensor groups 121 to 125 and the engine tachometer 126 are read.

  Next, in step S3, control states of various actuators (air conditioning control devices) 10a, 30 and 70a for air conditioning control are determined. Specifically, it is determined to be in the energized state as a control signal for the electromagnetic clutch 30, and further, a target blowout temperature TAO is calculated, and a control voltage Vfan applied to the electric motor of the blower fan 70a based on this TAO, The control current In of the electromagnetic capacity control valve 10a of the variable capacity compressor 10 is determined.

The target blowing temperature TAO is calculated by the following formula F1 based on the air conditioning thermal load fluctuation, the passenger compartment temperature (inside air temperature) Tr, and the set temperature Tset set by the temperature setting switch of the air conditioning operation switch SW.
TAO = Kset × Tset−Kr × Tr−Kam × Tam−Ks × Ts + C (F1)
Here, Tr is the inside air temperature detected by the inside air sensor 122, Tam is the outside air temperature detected by the outside air sensor 121, Ts is the amount of solar radiation detected by the solar radiation sensor 123, and Kset, Kr, Kam, and Ks are the control gain and C is a constant for correction.

  Next, in step S4, the estimated drive torque STrk of the variable displacement compressor 10 is estimated. Details of step S4 will be described with reference to the flowchart of FIG. First, in step S41, it is determined whether or not the variable displacement compressor 10 has just been started. Specifically, if the activation determination flag Tflg = 0, it is determined that it is immediately after activation, and the process proceeds to step S42. If Tflg = 0, it is determined that it is not immediately after activation, and the process proceeds to step S45.

  In step S42, from the time when the variable displacement compressor 10 starts compression based on the discharge refrigerant pressure Pd that is the discharge side detection value read in step S2 and the evaporator blown air temperature Te that is the suction side detection value. An estimated response time Ts until the compressor driving torque starts increasing is determined.

  Specifically, the suction refrigerant pressure Ps of the variable capacity compressor 10 is calculated from the evaporator blown air temperature Te, and further, the high-low pressure ratio Pd / Ps between the discharge refrigerant pressure Pd and the suction refrigerant pressure Ps is calculated. Based on the high / low pressure ratio Pd / Ps, an estimated response time Ts is determined with reference to a control map stored in the microcomputer 100 in advance.

  In the present embodiment, the map is such that the estimated response time Ts becomes longer as the high / low pressure ratio Pd / Ps increases. The estimated response time Ts is used to calculate the first estimated driving torque as will be described later.

  Next, in step S43, based on the discharge refrigerant pressure Pd that is the discharge-side detection value read in step S2 and the evaporator blown air temperature Te that is the suction-side detection value, the first estimated drive torque TrkA is set to the elapsed time T. The degree of increase ΔTrkA to be gradually increased with the increase of is determined. Specifically, similarly to the estimated response time Ts, it is determined with reference to a control map stored in advance in the microcomputer 100 based on the high / low pressure ratio Pd / Ps.

  In the present embodiment, the map is such that the increase degree ΔTrkA decreases as the high / low pressure ratio Pd / Ps increases. Accordingly, an estimation line for the first estimated driving torque with the elapsed time T as a variable as shown in FIG. 4 is determined by steps S42 and S43. FIG. 4 shows changes in actual driving torque (solid line), first estimated driving torque (broken line), and second estimated driving torque (two-dot chain line), which will be described later, under predetermined conditions.

  Next, in step S44, Tflg = 1 is set, and the process proceeds to step S45. Next, in step S45, the first estimated driving torque TrkA is calculated based on the first estimated driving torque estimation line and the elapsed time T. Accordingly, as shown in FIG. 4, the first estimated drive TrkA is 0 N · m when the elapsed time T is less than the estimated response time Ts, and according to the increase degree ΔTrkA when the elapsed time T is equal to or longer than the estimated response time Ts. The value gradually increases.

Next, in step S46, the second estimated drive torque TrkB is calculated based on the discharge refrigerant pressure Pd that is the discharge-side detection value read in step S2. Specifically, TrkB is calculated by the following mathematical formulas F2-4.
L = (κ / κ−1) × Psc × Qs × {(Pd / Psc) ⁽ κ− ^{1 /} κ ⁾ −1} (F2)
Qs = Vc × Nc × ηv (F3)
TrkB = L / Nc (F4)
Formula F2 is an expression generally used to calculate the power consumption L of the compressor, κ is an adiabatic index, and Psc is a representative value (fixed value) of the low-pressure side pressure when the refrigeration cycle is operating normally. ), Qs is the refrigerant flow rate in the gas phase on the compressor suction side.

  Formula F3 is an expression for calculating Qs, Vc is the discharge capacity, Nc is the compressor rotational speed, and ηv is the volumetric efficiency of the compressor. Therefore, κ, Psc, and ηv can be fixed values. Further, Vc can be calculated from the control current In determined in step 3, and Nc can be calculated by multiplying the engine speed Ne read in step S2 by the pulley ratio.

  Therefore, in step S46, the compressor consumption power L is calculated from the formulas F2 and 3 based on the discharge refrigerant pressure Pd, and the second estimated drive torque TrkB is calculated from the formula F4. Therefore, as shown in FIG. 4, the second estimated driving torque TrkB is a value determined by a change in only the discharge refrigerant pressure Pd.

  Therefore, in the present embodiment, the first estimated drive torque calculating means in which steps S41 to S45 calculate the first estimated drive torque TrkA of the variable displacement compressor 10 based on the discharge side detected value Pd and the suction side detected value Ps. Thus, step S46 serves as second estimated drive torque calculating means for calculating the second estimated drive torque TrkB of the variable displacement compressor 10 based on the discharge side detection value Pd.

  Next, in step S47, if TrkA <TrkB, the process proceeds to step S48, where estimated drive torque STrk = TrkA, and if not TrkA <TrkB, the process proceeds to step S49, where estimated drive torque STrk = TrkB. That is, in steps S47 to S49, a smaller value of TrkA and TrkB is adopted as the estimated drive torque STrk, and the process proceeds to step S5 in FIG.

  Therefore, in this embodiment, steps S47 to S49 serve as estimated drive torque determining means that employs a smaller value as the estimated drive torque STrk among the first estimated drive torque TrkA and the second estimated drive torque TrkB.

  Next, in step S5, the drive voltage Visc output to the idle adjustment valve 20c is determined. The drive voltage Visc is determined so that the engine speed Ne approaches a predetermined target idle speed Nco (for example, 600 to 800 rpm) when the engine is in an idle state.

  Specifically, the drive voltage Vn is determined by adding the additional drive voltage Visc2 corresponding to the estimated drive torque STrk to the reference drive voltage Visc1 that is determined in advance so that the engine speed becomes the target idle speed Nco. do it.

  Next, in step S6, the idle control valve 20c and the air conditioning control devices 10a, 30 and 30 are respectively connected from the microcomputer 100 via the drive circuits 131 to 133 so that the control state determined in steps S3 and S5 is obtained. An output signal is output to 70a. Then, in the next step S7, when waiting for the control period τ and the elapse of the control period τ are determined, the process returns to step S2.

  In the present embodiment, the estimated driving torque STrk of the variable displacement compressor 10 is estimated by the control as described above, and the driving voltage output from the microcomputer 100 to the idle control valve 20c based on the estimated driving torque STrk. By controlling Visc, the engine speed during idling does not fluctuate even if the driving torque of the compressor changes.

  Therefore, the high pressure sensor 125, the evaporator temperature sensor 124, the electric control unit, and step S4 of the control routine constitute a compressor driving torque estimation device, and further, this compressor driving torque estimation device, idle control valve The compressor drive source controller is configured by steps S5 and S6 of the electric control unit and the control routine 20c.

  Further, in the present embodiment, the first estimated drive torque calculating means S41 to S45 determine the estimated response time Ts and the increase degree ΔTrkA based on the discharged refrigerant pressure Pd and the evaporator blown air temperature Te, and the first estimated drive torque TrkA. Therefore, as shown in FIG. 4, the first estimated driving torque TrkA is prevented from being deviated from the actual compressor driving torque in the transient state immediately after the compression of the variable displacement compressor 10 is started. A highly accurate estimated value can be obtained.

  Since the estimated drive torque determining means S47 to S49 employ a smaller value as the estimated drive torque STrk among the first estimated drive torque TrkA and the second estimated drive torque TrkB, the first estimated drive in the transient state immediately after the start of compression. Torque TrkA is employed. Further, after the refrigeration cycle Rc is stabilized, the second estimated driving torque TrkB calculated by the above-described mathematical formulas F2 to F4 is employed.

  That is, in this embodiment, even in the transient state immediately after the start of compression of the variable displacement compressor 10, the idling speed is based on the highly accurate estimated drive torque STrk in which the deviation from the actual drive torque is suppressed. Since the control is performed, the stability of the idle speed can be greatly improved.

(Second Embodiment)
In the first embodiment, the discharge refrigerant pressure Pd is adopted as the discharge side detection value. However, in this embodiment, the control current In of the electromagnetic capacity control valve 10a of the variable displacement compressor 10 is used as the discharge side detection value. adopt. Other configurations are the same as those in the first embodiment.

  FIG. 5 is a graph showing the correlation between the discharge refrigerant pressure Pd and the control current In, in which the vertical axis represents the discharge refrigerant pressure Pd and the horizontal axis represents the control current In. Furthermore, the investigation results obtained by changing the refrigerant discharge flow rate of the variable capacity compressor 10 into three conditions of low flow rate, medium flow rate, and high flow rate are plotted. As shown in FIG. 5, there is a correlation between the control current In and the discharge refrigerant pressure Pd at any flow rate.

  Therefore, even when the control current In of the electromagnetic capacity control valve 10a is adopted as the discharge side detection value, the same effect as in the first embodiment can be obtained. Furthermore, since the control current In is an electric signal, it can be easily detected.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be variously modified as follows.

  (1) In the above-described embodiment, the discharge refrigerant pressure Pd and the control current In of the electromagnetic capacity control valve 10a are adopted as the discharge side detection value, but the discharge side detection value is not limited to this. For example, it is possible to adopt a compressor rotational speed or the like under a predetermined condition.

  Further, the discharge refrigerant pressure Pd is not limited to the refrigerant pressure immediately after the discharge of the variable capacity compressor 10, but the high pressure side refrigerant pressure in the refrigerant passage from the discharge side of the variable capacity compressor 10 to the inlet side of the expansion valve 60. It may be a detected value.

  (2) In the above-described embodiment, the evaporator outlet air temperature Te is adopted as the suction side detection value, but the suction side detection value is not limited to this. For example, the temperature of the heat exchange fin of the evaporator 60 may be adopted as the suction side detection value.

  Further, a low pressure sensor that detects the pressure of the refrigerant sucked by the variable displacement compressor 10 (the refrigerant pressure in the pipe P1) is adopted as the suction side detection means, and the suction refrigerant pressure Ps detected by the low pressure sensor is used as the suction side detection value. May be adopted. The suction refrigerant pressure Ps may be a value obtained by detecting the low-pressure side refrigerant pressure in the refrigerant passage extending from the expansion valve 60 outlet side to the variable displacement compressor 10 suction side.

  (3) In the above-described embodiment, the estimated drive torque determination means S47 to S49 employs a smaller value as the estimated drive torque STrk among the first estimated drive torque TrkA and the second estimated drive torque TrkB. When the elapsed time T is less than a predetermined reference time, the first estimated driving torque TrkA may be adopted as the estimated driving torque STrk in preference to the second estimated driving torque TrkB.

  According to this, regardless of the magnitude of the first estimated driving torque TrkA and the second estimated driving torque TrkB, when the elapsed time T is less than the predetermined reference time, the first estimated driving torque TrkA is used as the estimated driving torque STrk. Adopted. Therefore, the first estimated driving torque TrkA is reliably adopted as the estimated driving torque STrk in the transient state at the start of compression.

  (4) In the above-described embodiment, the estimated response time Ts and the estimated increase degree ΔTrkA are determined based on the high / low pressure ratio Pd / Ps. However, the means for determining the estimated response time Ts and the estimated increase degree ΔTrkA is limited to this. Not. For example, a plurality of control maps corresponding to combinations of the discharge refrigerant pressure Pd and the suction refrigerant pressure Ps are stored in advance in the microcomputer 100, and Ts and ΔTrkA are determined with reference to these control maps. Good.

  In the above-described embodiment, ΔTrkA is determined based on the high / low pressure ratio Pd / Ps at the start of compression of the variable displacement compressor 10, but the discharge side detection value and the suction side detection value are also set after the compression starts. Based on this, ΔTrkA may be changed sequentially. According to this, it is possible to estimate the estimated driving torque STrk with higher accuracy.

  (5) In the above-described embodiment, a predetermined value is adopted as the reference drive voltage Visc1 when determining the drive voltage Visc of the idle adjustment valve 20c. However, this reference drive voltage Visc1 is controlled by another control. A deviation En (En = Nco-Ne) between the engine speed Ne and the target idle speed Nco is calculated by a routine, and feedback based on proportional-integral control (PI control) or the like is performed so that Ne approaches Nco based on the deviation En. The value determined by the control method may be used.

  Further, in the control routine for idle speed control using the estimated drive torque STrk in the above-described embodiment, the feedback control may be performed concurrently.

  (6) In the above-described embodiment, the microcomputer 100 and its peripheral circuits 110 and 131 to 133 constitute an electric control unit, and the single electric control unit controls the air conditioning control devices 10a, 30, and 70a, and the estimated driving torque. Although the determination of STrk and the control of the idle adjustment valve 20c are performed, the above-described control may be performed while communicating with a plurality of electric control units.

  For example, in a general vehicle in which the air-conditioning control ECU controls the air-conditioning control devices 10a, 30, and 70a and the engine ECU controls the idle adjustment valve 20c, one of the ECUs determines the estimated drive torque STrk. It may be.

  (7) The application of the present invention is not limited to the idle speed control device, and is not limited to the above-described embodiment as long as it matches the gist of the invention described in the claims. It can be applied to various uses.

  For example, the present invention can also be applied to a stationary heater or a cooler having a variable capacity compressor using a stationary engine as a drive source. Further, in a system having a variable capacity compressor using an electric motor as a drive source, in order to keep the rotation speed of the electric motor constant, the amount of power supplied to the motor is controlled based on the estimated drive torque STrk. Applicable.

It is a whole block diagram of the idle speed control apparatus of 1st Embodiment. It is a flowchart which shows control of the idle speed control apparatus of 1st Embodiment. It is a flowchart which shows the principal part of control of the idle speed control apparatus of 1st Embodiment. It is explanatory drawing explaining the relationship between the estimated drive torque of 1st Embodiment, and an actual drive torque. It is a graph which shows the relationship between discharge refrigerant | coolant pressure and control current. It is explanatory drawing explaining the change of an actual drive torque.

Explanation of symbols

10 ... Variable capacity compressor, 125 ... High pressure sensor, 124 ... Evaporator temperature sensor,
S41 to S45: first estimated driving torque calculating means, S46: second estimated driving torque calculating means,
S47 to S49: Estimated driving torque determining means,
TrkA: first estimated driving torque, TrkB: second estimated driving torque,
STrk ... Estimated driving torque, Pd ... Discharge refrigerant pressure, In ... Control current,
Ps ... Intake refrigerant pressure, Te ... Evaporator air temperature, Ts ... Estimated response time,
ΔTrkA: degree of increase, T: elapsed time.

Claims (8)

A compressor driving torque estimation device for estimating a driving torque of a variable displacement compressor (10) configured to be capable of changing a discharge capacity,
A discharge side detecting means (125) for detecting a physical quantity related to the discharge side pressure of the variable capacity compressor (10);
Suction side detection means (124) for detecting a physical quantity related to the suction side pressure of the variable displacement compressor (10);
Based on the discharge side detection values (Pd, In) detected by the discharge side detection means (125) and the suction side detection values (Te, Ps) detected by the suction side detection means (124), the variable displacement compression First estimated drive torque calculating means (S41 to S45) for calculating the first estimated drive torque (TrkA) of the machine (10);
Second estimated drive torque calculating means (S46) for calculating a second estimated drive torque (TrkB) of the variable displacement compressor (10) based on the discharge side detection values (Pd, In);
It comprises estimated drive torque determining means (S47 to S49) that employs a smaller value of the first estimated drive torque (TrkA) and the second estimated drive torque (TrkB) as the estimated drive torque (STrk). A compressor driving torque estimating device. The first estimated drive torque calculating means (S41 to S45) determines an estimated response time (Ts) from when the variable displacement compressor (10) starts compression until the drive torque starts increasing. And
Further, the first estimated drive torque calculating means (S41 to S45) is configured such that an elapsed time (T) from when the variable displacement compressor (10) starts compression is less than the estimated response time (Ts). When the first estimated driving torque (TrkA) is 0 N · m and the elapsed time (T) is equal to or longer than the estimated response time (Ts), the first estimated driving torque (TrkA) is set to the elapsed time (T). The compressor driving torque estimation device according to claim 1, wherein the calculation is performed so as to gradually increase as the value increases. The first estimated drive torque calculation means (S41 to S45) are configured to detect the discharge side detection value (Pd, In) and the suction side detection value (Te, Ps) at the start of compression of the variable displacement compressor (10). The compressor drive torque estimating device according to claim 2, wherein the estimated response time (Ts) is determined based on The first estimated drive torque calculation means (S41 to S45) are configured to detect the discharge side detection value (Pd, In) and the suction side detection value (Te, Ps) at the start of compression of the variable displacement compressor (10). 4. The compressor driving torque estimating device according to claim 2, wherein an increase degree (ΔTrkA) for gradually increasing the first estimated driving torque (TrkA) is determined based on the above. When the elapsed time (T) is less than a predetermined reference time, the estimated drive torque determining means (S47 to S49) gives priority to the first estimated drive torque (TrkA) over the second estimated drive torque (TrkB). ) Is adopted as the estimated driving torque (STrk), the compressor driving torque estimating device according to any one of claims 2 to 4. The variable capacity compressor (10) is configured such that the discharge capacity is changed by an external electric control signal (In),
The compressor drive torque estimating device according to any one of claims 1 to 5, wherein the discharge side detection value is the control signal (In). A compressor drive torque estimating device according to any one of claims 1 to 6, comprising:
Compressor drive source control for controlling the output of a drive source for applying a drive force to the variable displacement compressor (10) based on the estimated drive torque (STrk) estimated by the compression drive torque estimation device apparatus. The variable capacity compressor (10) is mounted on a vehicle air conditioner,
The compressor drive source control device according to claim 7, wherein the drive source is a vehicle engine.

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