JP2008201335A - Vehicular air-conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular air-conditioner for controlling the discharge displacement of a compressor by the target evaporator temperature and the evaporator temperature which is capable of reliably reducing the displacement of the compressor during the high-speed protective control operation and suppressing degradation of the air-conditioning feeling of an occupant. <P>SOLUTION: The vehicular air-conditioner comprises a variable displacement type compressor 11 to be driven by an engine of a vehicle, an evaporator 9 for cooling air flowing in a cabin by evaporating a refrigerant, a temperature detection means 34 for detecting the temperature of the evaporator, a displacement control means 11b for controlling the discharge displacement so that the evaporator temperature reaches the target evaporator temperature, and a rotation number detection means for detecting the number of rotation of the compressor 11. The displacement control means 11b sets the value of the evaporator temperature when the number of rotation of the compressor 11 exceeds the predetermined value with the preset permissible temperature rise added thereto as the target evaporator temperature when the number of rotation of the compressor 11 exceeds the predetermined value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle air conditioner.

  2. Description of the Related Art Conventionally, in a variable displacement compressor control device that drives a vehicle engine as a drive source and controls the refrigerant discharge capacity based on an external control signal, the actually measured evaporator temperature TE is the target evaporation. A method for controlling the capacity of the compressor so as to coincide with the temperature of the vessel TEO is widely known.

When this variable capacity compressor is used, high rotation protection control is performed to protect the compressor by reducing the capacity of the compressor in order to prevent mechanical destruction when the rotational speed of the compressor is high. . As a conventional technology for high-rotation protection control, a control for protecting the compressor by reducing the discharge capacity of the compressor by setting an upper limit value for the control current according to the rotation speed of the compressor and the discharge pressure of the compressor has been devised. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 10-159749

  However, when high rotation protection control is performed by setting an upper limit value for the control current according to the compressor speed and compressor discharge pressure, the compressor discharge capacity is reduced regardless of the air conditioning control in the vehicle. As a result, the passenger's air conditioning feeling may deteriorate.

  In view of the above points, the present invention provides a vehicle air conditioner that controls the discharge capacity of a variable capacity compressor using the target evaporator temperature TEO and the evaporator temperature TE. The purpose of this is to reduce the air conditioning feeling of the occupant as well as to reliably reduce the air conditioning.

  To achieve the above object, the present invention is connected to a refrigerant (11) driven by an engine E of a vehicle and capable of changing a refrigerant discharge capacity, and a refrigerant suction side of the compressor (11). An evaporator (9) for evaporating the refrigerant and cooling the air flowing through the passenger compartment, a temperature detecting means (34) for detecting the evaporator temperature TE, which is the temperature of the air after passing through the evaporator (9), and the evaporation Capacity control means (11b) for controlling the refrigerant discharge capacity of the compressor (11) such that the compressor temperature TE becomes the target evaporator temperature TEO, and a rotational speed detection means for detecting the rotational speed Nc of the compressor (11). The capacity control means (11b) is configured such that when the rotational speed of the compressor (11) exceeds a predetermined rotational speed, the rotational speed of the compressor (11) exceeds the predetermined rotational speed. Preset tolerance for evaporator temperature And sets a value obtained by adding the temperature temperature ΔT as the target evaporator temperature.

  Generally, when the refrigerant discharge capacity of the compressor (11) is controlled by the capacity variable means so that the evaporator temperature TE coincides with the target evaporator temperature TEO, the capacity state of the compressor (11) is It can be judged from the relationship between the evaporator temperature and the target evaporator temperature. Specifically, when the target evaporator temperature is lower than the evaporator temperature, the capacity of the compressor (11) is maximized (100%) or increased because the cooling capacity is insufficient with respect to the air conditioning heat load. Can be determined. When the target evaporator temperature is about the same as the evaporator temperature, it can be determined that the current capacity of the compressor (11) is maintained because the cooling capacity is balanced with the air conditioning heat load. When the target evaporator temperature is higher than the evaporator temperature, it is determined that the capacity of the compressor (11) is at a minimum (0%) or decreased because the cooling capacity is large with respect to the air conditioning heat load. be able to.

  That is, in the present invention, the capacity state of the compressor (11) can be determined from the relationship between the evaporator temperature and the target evaporator temperature, and the target evaporator temperature at the time of protection control operation is determined by the evaporator at the start of protection control. By setting the temperature higher than the temperature, the capacity of the compressor (11) can be reliably reduced.

  By the way, in protection control or the like with a relatively short operation time, a change in the air conditioning feeling of the occupant during the control operation is detected mainly by a change in the blowout temperature, so the compressor (11) during the protection control operation. The deterioration of the air conditioning feeling can be suppressed by setting the temperature rise of the evaporator (9) generated by reducing the capacity of the evaporator to be within the allowable increase temperature ΔT that can be allowed by the air conditioning feeling.

  The present invention combines these two, and the compressor (11) adds the second target evaporator temperature TEO2 during the high rotation protection control to the evaporator temperature TE at the start of the control and the allowable increase temperature that can be allowed during the protection control operation. By performing the capacity control of the compressor (11) as a value, it is possible to suppress the deterioration of the air conditioning feeling of the occupant while reliably reducing the capacity of the compressor (11).

  The engine load detecting means for detecting the engine load information of the vehicle and the engine load determining means for determining the engine load state based on the engine load information are provided. When it is determined that the target evaporator temperature is set to a value obtained by adding a preset allowable rise temperature ΔT to the evaporator temperature when it is determined that there is a high load state, the vehicle engine load is high. It is possible to reliably reduce the capacity of the compressor (11) in the load state and suppress deterioration of the passenger's air conditioning feeling.

  The capacity control means (11b) controls the refrigerant discharge capacity by controlling the suction pressure Ps of the compressor (11) so that the evaporator temperature becomes the target evaporator temperature. It is possible to reliably reduce the capacity of the passenger and to suppress the deterioration of the air conditioning feeling of the occupant.

  Further, the capacity control means (11b) reduces the allowable rise temperature ΔT as the difference between the target blow temperature TAO of the air blown into the passenger compartment and the evaporator temperature increases, so that the target blow temperature TAO and the evaporator temperature are reduced. When the allowable increase temperature ΔT is increased as the difference between the two increases, the degree of deterioration of the passenger's air conditioning feeling can be adjusted.

  Further, the capacity control means (11b) sets the evaporator temperature increase ΔT so that the allowable increase temperature ΔT increases as the rotation speed of the compressor (11) increases, and as the rotation speed of the compressor (11) decreases. When the allowable rise temperature ΔT is reduced, the degree of reduction of the capacity of the compressor (11) can be adjusted.

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

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows an outline of the overall configuration of the present embodiment, and a vehicle air conditioner includes an indoor air conditioning unit 1 disposed on the inside of an instrument panel (instrument panel) at the forefront of a vehicle interior.

  This indoor air-conditioning unit 1 has a case 2 and constitutes an air passage through which air is blown toward the vehicle interior. An inside / outside air switching box 5 having an inside air introduction port 3 and an outside air introduction port 4 is arranged at the most upstream part of the air passage of the case 2. Inside / outside air switching box 5, an inside / outside air switching door 6 as inside / outside air switching means is rotatably arranged.

  The inside / outside air switching door 6 is driven by a servo motor 7, and an inside air mode for introducing inside air (vehicle compartment air) from the inside air introduction port 3 and an outside air for introducing outside air (vehicle compartment outside air) from the outside air introduction port 4. Switch between a mode and a semi-inside air mode that introduces inside air and outside air at the same time.

  On the downstream side of the inside / outside air switching box 5, an electric blower 8 that blows air toward the passenger compartment is disposed. The blower 8 is configured to drive a centrifugal blower fan 8a by a motor 8b. An evaporator 9 serving as a cooling heat exchanger for cooling the blown air is disposed on the downstream side of the blower 8.

  The evaporator 9 is one of the elements constituting the refrigeration cycle apparatus 10. The low-pressure refrigerant that has flowed into the evaporator 9 absorbs heat from the blown air blown by the blower 8 and evaporates, thereby cooling the blown air. The evaporator 9 is a cooling heat exchanger in this embodiment. The refrigeration cycle apparatus 10 is a well-known device, and includes an evaporator 9, a compressor 11, a condenser 12, a gas-liquid separator 13, and an expansion valve 14.

  The compressor 11 is rotationally driven by the rotational power of the vehicle engine E transmitted through the electromagnetic clutch 11a, the pulley 11b, and the belt V. Details of the compressor 11 will be described later.

  The condenser 12 is a radiator that cools the refrigerant by exchanging heat between the refrigerant discharged from the compressor 11 and the outside air. A blower fan 12a that blows outside air to the condenser 12 is driven by a motor 12b. The refrigerant flowing out of the condenser 12 flows into a gas-liquid separator 13 (receiver) that separates the refrigerant into a gas-phase refrigerant and a liquid-phase refrigerant.

  The expansion valve 14 decompresses and expands the liquid-phase refrigerant separated by the gas-liquid separator 13. In this embodiment, the expansion valve 14 decompresses the refrigerant in an enthalpy manner and superheats the refrigerant sucked into the compressor 11. A temperature type expansion valve that controls the opening degree of the throttle so that becomes a predetermined value is employed.

  The refrigerant expanded under reduced pressure flows into the evaporator 9 and evaporates, and then flows into the compressor 11 again. Thus, a refrigeration cycle in which the refrigerant circulates in the order of the compressor 11 → the condenser 12 → the gas-liquid separator 13 → the expansion valve 14 → the evaporator 9 → the compressor 11 is configured. The refrigeration cycle components (9, 11 to 14) described above are connected to each other by refrigerant piping.

  On the other hand, in the indoor air conditioning unit 1, a heater core 15 that heats the air flowing in the case 2 is disposed on the downstream side of the evaporator 9. The heater core 15 is a heat exchanger for heating that uses the vehicle engine coolant as a heat source (the engine coolant circuit is not shown) and heats the air (cold air) after passing through the evaporator 9. A bypass passage 16 is formed on the side of the heater core 15, and the bypass air of the heater core 15 flows through the bypass passage 16.

  Between the evaporator 9 and the heater core 15, an air mix door 17 serving as a temperature adjusting means is rotatably arranged. The air mix door 17 is driven by a servo motor 18 so that its rotational position (opening degree) can be continuously adjusted.

  The ratio of the amount of air passing through the heater core 15 (warm air amount) and the amount of air passing through the bypass passage 16 and bypassing the heater core 15 (cold air amount) is adjusted by the opening degree of the air mix door 17. The temperature of the air blown into the room is adjusted.

  At the most downstream part of the air passage of the case 2, a defroster outlet 19 for blowing conditioned air toward the front window glass W of the vehicle, a face outlet 20 for blowing conditioned air toward the face of the occupant, A total of three types of air outlets 21 are provided, which are foot outlets 21 for blowing air-conditioned air toward the feet of passengers.

  A defroster door 22, a face door 23, and a foot door 24 are rotatably disposed upstream of the air outlets 19 to 21. The doors 22 to 24 are opened and closed by a common servo motor 25 via a link mechanism (not shown).

  Next, the compressor 11 will be described. The compressor 11 of the present embodiment uses a variable capacity compressor that continuously varies the discharge capacity by a control current Iout from the outside.

  This variable capacity compressor is a known one. For example, in a swash plate compressor, a variable capacity apparatus having an electromagnetic pressure control device that controls the pressure Pc of the swash plate chamber using the discharge pressure Pd and the suction pressure Ps. 11b. By controlling the pressure in the swash plate chamber with this capacity variable device 11b, the tilt angle of the swash plate is varied to continuously change the stroke of the piston, that is, the discharge capacity of the compressor 11 in a range of approximately 0% to 100%. Can be made. This capacity variable device 11b corresponds to capacity control means in the present invention.

  The electromagnetic pressure control device of the capacity variable device 11b changes the control pressure Pc (swash plate chamber pressure) using the discharge pressure Pd and the suction pressure Ps of the compressor 11, and the electromagnetic force is generated by the control current Iout. An electromagnetic mechanism to be adjusted and a valve body that is displaced by a balance between the electromagnetic force of the electromagnetic mechanism and the suction pressure, and the pressure loss of the passage that guides the discharge pressure of the compressor 11 into the swash plate chamber is adjusted by the valve body. Thus, the control pressure is changed.

  Energization of the variable capacity device 11b to the electromagnetic pressure control device is controlled by an air conditioning control device (ECU) 30. When the control current Iout of the variable capacity device 11b is increased, the discharge capacity of the compressor 11 is increased. It has become. On the other hand, when the discharge capacity of the compressor 11 increases, the suction pressure Ps of the refrigeration cycle decreases. That is, the control current Iout of the variable capacity device 11b determines the target suction pressure Pso of the refrigeration cycle, and the target suction pressure Pso decreases in inverse proportion to the increase in the control current Iout (see FIG. 2).

  Accordingly, the discharge capacity of the compressor 11 is increased or decreased by increasing or decreasing the control current Iout to raise or lower the actual suction pressure Ps, so that the temperature of the evaporator 9 (evaporator temperature TE) becomes a predetermined final target evaporator temperature TEO (target). The cooling capacity of the evaporator 9 can be controlled so that the temperature corresponds to the suction pressure Pso). Here, the control current Iout is specifically variable by duty control, but the value of the control current Iout may be increased or decreased directly (analog) directly without using duty control.

  Further, the compressor 11 can continuously change the discharge capacity from 100% to approximately 0% by adjusting the control pressure Pc. Then, by reducing the discharge capacity to approximately 0%, the compressor 11 is substantially stopped. Therefore, it is possible to adopt a clutchless configuration in which the rotation shaft of the compressor 11 is always connected to the pulley on the vehicle engine E side through the pulley, the belt V, and the like.

  Next, the outline of the electric control unit according to the present embodiment will be described. The air conditioning control device 30 includes a known microcomputer including a CPU, a ROM, a RAM, and the like and peripheral circuits thereof. The air conditioning control device 30 stores an air conditioning device control program in its ROM, and performs various calculations and processes based on the air conditioning device control program. This air conditioning control device 30 corresponds to the air conditioning control means in the present invention.

  Sensor detection signals are input from the air conditioning sensor groups 31 to 35 to the input side of the air conditioning control device 30, and various air conditioning operation switches 37 to 37 provided on the air conditioning operation panel 36 disposed in the vicinity of the instrument panel in the front part of the vehicle interior. An operation signal is input from 42, and sensor detection signals are input from the engine sensor groups 43 to 45.

  Specifically, the air conditioning sensor group includes an outside air sensor 31 that detects the outside air temperature TAM, an inside air sensor 32 that detects the inside air temperature TR, a solar radiation sensor 33 that detects the amount of solar radiation TS that enters the vehicle interior, and the evaporator 9. An evaporator temperature sensor 34 for detecting the evaporator temperature TE and a water temperature sensor 35 for detecting the engine coolant temperature TW flowing into the heater core 15 are provided.

  The air-conditioning operation panel 36 has various air-conditioning operation switches, such as a blow mode switch 37 for manually setting the blow mode switched by the blow mode doors 22 to 24, and an internal / external air switch for manually setting the internal / external air suction mode by the internal / external air switching door 6. A switch 38, an air conditioner switch 39 for outputting an operation command signal for the compressor 11 (an ON signal for the electromagnetic clutch 11a), a blower operation switch 40 for manually setting the air volume of the blower 8, an auto switch 41 for issuing a command signal for an air conditioning automatic control state, In addition, a temperature setting switch 42 and the like serving as temperature setting means for setting the vehicle interior temperature are provided.

  As an engine sensor group, an engine speed sensor 43 that detects the speed of the engine E, a vehicle speed sensor 44 that detects the speed of the vehicle, and an accelerator opening that detects the amount of depression of the accelerator pedal of the driver (accelerator opening). A sensor 45 is provided.

  On the output side of the air-conditioning control device 30, there are an electromagnetic clutch 11a of the compressor 11, a capacity variable device 11b, servo motors 7, 18, 25 serving as electric drive means for each device, a motor 8b of the blower 8, and a condenser cooling fan. The motor 12 b of 12 a is connected, and the operation of these devices is controlled by the output signal of the air conditioning control device 30.

  Next, in the present embodiment, the overall control processing executed by the air conditioning control device 30 will be described based on the flowchart of FIG. At the start of this control routine, the vehicle engine E is activated, and the vehicle air conditioner air conditioner switch 41 is in an ON state.

  First, in S10, initial values for capacity control are set. Specifically, the sampling count n = 1, the temperature deviation E (n−1) = 0, and the initial value of the state flag Fhi indicating the operating state of the high rotation protection control are set as initial values. Here, the relationship between the value of the status flag Fhi and the high rotation protection control operation status is that if Fhi = 0, the high rotation protection control is performed from the normal time (the first protection control operation), and if Fhi = 1, the high rotation protection control is in operation. (Protection control operation second and subsequent times) is shown.

  In S20, various information indicating the operating state of the air conditioner including the engine speed Ne (n), the accelerator opening degree of the vehicle, and the vehicle speed, and the evaporator temperature TE measured by the evaporator temperature sensor 34 are read.

  Next, the target blowing temperature TAO of the blowing air into the vehicle interior is calculated in S30. This target air temperature TAO is the temperature of air blown into the vehicle interior required to maintain the vehicle interior at the set temperature TSET set by the occupant using the temperature setting switch 42 on the air conditioning operation panel 36 regardless of the air conditioning thermal load fluctuation. Thus, the target blowing temperature TAO is calculated based on the set temperature TSET, the outside air temperature TAM, the inside air temperature TR, the solar radiation amount TS, and the like as is well known.

  Next, the first target evaporator temperature TEO1 is calculated in S40. The first target evaporator temperature TEO1 is a target temperature of the evaporator outlet air, and is determined based on the target outlet temperature TAO determined for the vehicle interior temperature control.

  In S50, the control current Iout of the capacity variable device 11b is calculated from the first target evaporator temperature TEO1 and the evaporator temperature TE. A method for calculating the control current Iout will be described in detail later.

  Next, the control current Iout is output to the capacity variable device 11b of the compressor 11 in S60, and the capacity control of the compressor 11 is executed.

  In S70, it is determined whether or not to continue the capacity control of the compressor 11. If it is determined in S70 that the capacity control of the compressor 11 is to be continued, 1 is added to the sampling count n in S80. Thereafter, the process returns to S20 and the capacity control of the compressor 11 is continued. When it is determined in S70 that the capacity control of the compressor 11 is not continued, the capacity control of the compressor 11 is terminated in S90.

  Next, the control current calculation process performed in S50 in the present embodiment will be described with reference to FIGS. FIG. 4 shows a flowchart of a control current calculation process executed by the air conditioning control device 30. FIG. 5 shows the relationship between the compressor rotation speed Nc for determining whether or not to implement the high rotation protection control and the control flag F.

  First, in S100, the temperature deviation E (n) is calculated by subtracting the first target evaporator temperature TEO1 (n) from the evaporator temperature TE (n).

  Next, in S200, the engine speed Ne (n) is multiplied by the pulley ratio to calculate the compressor speed Nc (n). The pulley ratio is the ratio of the compressor speed Nc (n) to the engine speed Ne (n), and is generally a value determined by the design specifications of the vehicle and the air conditioner. If the compressor rotational speed Nc (n) is obtained directly from the value detected by the rotational speed sensor, the control may be performed using that value. This S200 corresponds to the rotational speed detection means in the present invention.

  Next, in S300, it is determined whether or not to implement high rotation protection control based on the compressor rotation speed Nc (n). As shown in FIG. 5, the control flag F is set to F = 0 if the compressor rotational speed Nc (n) is smaller than the threshold value A, and it is determined to perform the normal control. If the compressor speed Nc (n) is greater than or equal to the threshold value A, F = 1 is set, and it is determined that the high speed protection control is to be performed. Here, the threshold value A of the compressor rotation speed indicates an upper limit value for normally operating the compressor 11.

  Hereinafter, the case where normal control is performed (F = 0) and the case where high rotation protection control is performed (F = 1) will be described separately.

  Returning to FIG. 4, in S400, if it is determined in S300 that the control flag F = 0, that is, normal time (high rotation protection control inactive), the state flag Fhi = 0 indicating the operation state of the high rotation protection control is set. .

Next, in S410, the control current Iout (n) of the variable capacity device 11b is calculated using Equation 1 shown below using the temperature deviations E (n) and E (n-1). Here, Formula 1 shows proportional integral control (PI control).
(Formula 1)
Iout (n) = Iout (n−1) + Kp (E (n) −E (n−1)) + (Θ / Ti) × E (n)
Here, Kp, (Θ / Ti) indicates a feedback gain.

  In S410, the control value Iout (n) of the compressor 11 is determined by a feedback control method using proportional-integral control (PI control), but feedback control in which a differential term is added to a proportional term and an integral term is used. Thus, the control value Iout (n) may be calculated.

  Next, when it is determined in S300 that the control flag F = 1, that is, the high rotation protection control is to be performed, immediately after the high rotation protection control is activated from the normal control by the state flag Fhi indicating the operation state of the protection control in S500, Determine whether high-rotation protection control is operating.

  In S510, when the state flag is Fhi = 0, it can be determined that the high-rotation protection control has just been activated from the normal control, and the state flag Fhi = 1 is set. Here, although not shown, the temperature deviation Ehi (n−1) = 0 is set as an initial value. In S520, the evaporator temperature TE (n) immediately after the high rotation protection control operation is stored in the reference evaporator temperature TEhi.

  Further, when the state flag Fhi = 1, it can be determined that the protection control is in operation (the second and subsequent protection control operations), so S510 and S520 are skipped.

  Next, in S530, the second target evaporator temperature TEO2 is calculated by adding the allowable increase temperature ΔT to the reference evaporator temperature TEhi which is the evaporator temperature TE immediately after the high rotation protection control operation. Here, the allowable increase temperature ΔT is a temperature increase amount (for example, 5 ° C.) that the occupant can allow in the air conditioning feeling, and is set to a value larger than 0 ° C. Further, the allowable increase temperature ΔT is stored in advance in the ROM or the like of the air conditioning control device 30. Therefore, the second target evaporator temperature TEO2 calculated in S530 is always set at a temperature higher than the reference evaporator temperature TEhi that is the evaporator temperature immediately after the high rotation protection control operation.

  Generally, when the capacity of the compressor 11 is controlled so that the evaporator temperature TE coincides with the target evaporator temperature TEO, the capacity state of the compressor 11 is determined by the evaporator temperature TE and the target evaporator temperature TEO. It can be judged from the relationship. Specifically, when the target evaporator temperature TEO is lower than the evaporator temperature TE, the capacity of the compressor 11 is maximized (100%) or increased because the cooling capacity is insufficient with respect to the air conditioning heat load. Can be determined. When the target evaporator temperature TEO is approximately the same as the evaporator temperature TE, it can be determined that the current capacity of the compressor 11 is maintained because the cooling capacity is balanced with the air conditioning heat load. When the target evaporator temperature TEO is higher than the evaporator temperature TE, it is determined that the capacity of the compressor 11 is at a minimum (0%) or decreased because the cooling capacity is larger than the air conditioning heat load. be able to.

  In the present embodiment, the second target evaporator temperature TEO2 at the time of the high rotation protection control operation is set higher than the reference evaporator temperature TEhi that is the evaporator temperature immediately after the high rotation protection control operation. The capacity can be reliably reduced.

  Further, in the control with a relatively short operation time such as the high rotation protection control, a change in the air conditioning feeling of the occupant during the control operation is detected mainly by a change in the blowing temperature. Therefore, the deterioration of the air conditioning feeling can be suppressed by setting the temperature rise amount of the evaporator generated by reducing the capacity of the compressor 11 during the high rotation protection control operation to the allowable rise temperature.

  Next, in S540, a temperature deviation Ehi (n) between the second target evaporator temperature TEO2 and the evaporator temperature TE (n) during the protection control operation is calculated. In S550, using the temperature deviations Ehi (n) and Ehi (n-1), a control value Iouthi (n) at the time of protection control operation is calculated by proportional integral control (PI control) similar to S410. In S560, the control current Iout (n) is replaced with the control current Iouthi (n) during the protection control operation.

  As described above, the second target evaporator temperature TEO2 during the high-rotation protection control is calculated by adding the allowable increase temperature ΔT that can be allowed by the occupant during the protection control operation to the reference evaporator temperature TEhi at the start of the control, Since the control current of the capacity variable device 11b is calculated from the target evaporator temperature TEO2, the deterioration of the air conditioning feeling of the occupant can be suppressed while reliably reducing the capacity of the compressor 11.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, only the parts different from the first embodiment will be described. FIG. 6 shows the relationship between the control flag F for determining whether or not to implement the high rotation protection control used in the present embodiment and the compressor rotational speed Nc.

  The present embodiment is different in the determination method of the control flag F in the high rotation protection control determination (S300) of FIG. 4 shown in the first embodiment.

  In the first embodiment, as shown in FIG. 5, when determining whether or not to implement the high rotation protection control, the determination is made based on the compressor rotation speed Nc and the threshold A. In this embodiment, as shown in FIG. 6, when determining whether or not to implement the high rotation protection control, hysteresis is applied to the determination of the control flag F using the two values of the compressor rotation speed threshold values B1 and B2. The control branches to normal control or high-rotation protection control depending on the value of the control flag F. Here, the relationship between the threshold values B1 and B2 is set so that the threshold value B1 is always larger than the threshold value B2.

  That is, when the high rotation protection control is performed from the normal control state (F = 0), the threshold value B1 of the compressor rotation speed Nc is used, and the compressor rotation speed Nc (n) is smaller than the threshold value B1. Normal control is continued with the determination flag set to F = 0. If the compressor rotation speed Nc (n) is larger than the threshold value B1, the determination flag is set to F = 1 and high rotation protection control is performed.

  In addition, when the normal control is performed from the high rotation protection control state (F = 1), the determination flag is set to F = if the compressor rotation speed Nc is smaller than the threshold B2 using the compressor rotation speed threshold B2. Normal control is performed as 0. If the compressor rotational speed Nc (n) is equal to or greater than the threshold B2, the determination flag is set to F = 1 and high-rotation protection control is performed.

  In this way, by providing hysteresis when determining whether or not to implement the high rotation protection control, when the compressor rotation speed Nc (n) becomes a value near the high rotation protection control determination threshold value, It is possible to suppress the complicated switching of the high rotation protection control.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIGS. In the present embodiment, only the parts different from the first embodiment will be described. FIG. 7 shows the relationship between the allowable increase temperature ΔT and the target blowing temperature TAO during the high rotation protection control.

  This embodiment is different in the method for determining the allowable increase temperature ΔT in the second target evaporator temperature calculation in S530 of FIG. 4 shown in the first embodiment.

  In the first embodiment, when the second target evaporator temperature TEO2 is calculated, the allowable increase temperature ΔT added to the reference evaporator temperature TEhi in S530 is a fixed value. However, in the present embodiment, the allowable increase temperature ΔT Is changed according to the target blowing temperature TAO. That is, the allowable increase temperature ΔT is calculated from the control map (FIG. 7) of the allowable increase temperature ΔT and the target blowing temperature TAO stored in advance in the ROM or the like of the air conditioning control device 30.

  As described above, the degree of deterioration of the air conditioning feeling of the occupant can be adjusted by changing the method for determining the value of the allowable increase temperature ΔT according to the target blowing temperature TAO. For example, when the target blowout temperature TAO is high and the cooling load of the air conditioner is high, the amount of decrease in the capacity of the compressor 11 is reduced by reducing the value of the allowable rise temperature ΔT, and the degree of deterioration of the air conditioning feeling of the occupant Can be reduced. Further, when the target blowout temperature TAO is low and the cooling load of the air conditioner is low, the amount of decrease in the capacity of the compressor 11 can be increased and the compressor 11 can be protected by increasing the value of the allowable increase temperature ΔT. it can.

  In the present embodiment, the allowable increase temperature ΔT is changed according to the target blowing temperature TAO, but is not limited thereto, and may be changed according to, for example, the outside air temperature TAM that is external information.

(Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to FIGS. In the present embodiment, only the parts different from the first embodiment will be described. FIG. 8 shows the relationship between the allowable increase temperature ΔT and the rotation speed Nc (n) of the compressor 11 during the high rotation protection control.

  This embodiment is different from the first embodiment in the determination method of the allowable increase temperature ΔT in the second target evaporator temperature calculation of S530 shown in FIG. 4.

  In the first embodiment, when calculating the second target evaporator temperature TEO2, the allowable increase temperature ΔT to be added to the reference evaporator temperature TEhi in S530 is a fixed value.

  However, generally, in the high rotation protection control, the higher the compressor rotation speed Nc, the higher the load on the compressor 11, and thus the degree of reduction in the capacity of the compressor 11 needs to be increased. In the present invention, the degree to which the capacity of the compressor 11 is reduced is determined by the value of the allowable rise temperature ΔT. The greater the allowable rise temperature ΔT, the greater the degree to which the capacity of the compressor 11 is reduced.

  Therefore, in the present embodiment, the allowable increase temperature ΔT is changed according to the compressor rotational speed Nc (n). That is, the allowable increase temperature ΔT (n) is calculated from the control map (FIG. 8) of the allowable increase temperature ΔT and the compressor rotation speed Nc (n) stored in advance in the ROM or the like of the air conditioning control device 30.

  As described above, the degree of decrease in the capacity of the compressor 11 can be adjusted by changing the method for determining the value of the allowable increase temperature ΔT in accordance with the compressor rotational speed Nc (n). For example, the value of the allowable temperature rise ΔT is increased as the compressor speed Nc (n) is higher, and the degree of reduction in the capacity of the compressor 11 is increased as the compressor speed Nc is higher during the high speed protection control. And the compressor 11 can be reliably protected. Further, when the compressor rotation speed Nc is not so high, the degree of deterioration of the passenger's air conditioning feeling can be reduced by reducing the value of the allowable increase temperature ΔT.

(Fifth embodiment)
A fifth embodiment of the present invention will be described with reference to FIGS. In the present embodiment, only the parts different from the first embodiment will be described. FIG. 9 is a flowchart showing control current calculation processing in the present embodiment.

  This embodiment is different from FIG. 4 shown in the first embodiment in that the timer (Time) is counted in S401 after setting the state flag in S400 and before calculating the control current in S410. The timer determination is performed in S511 after the state flag is set in S510 and before the storage of the evaporator temperature in S520, and the timer is initialized in S570 after S560.

  In the first embodiment, for example, the capacity of the compressor 11 is reduced by the first high-rotation protection control operation, the evaporator temperature TE is increased, and a short time after returning to the normal control by the high-rotation protection control determination in S300. When the second high rotation protection control is activated, the increased evaporator temperature TE is calculated as the reference evaporator temperature TEhi immediately after the second high rotation protection control operation. If this continues, the reference evaporator temperature rises and the target evaporator temperature TEO rises, so the passenger's air conditioning feeling may deteriorate.

  Therefore, in the fifth embodiment, as shown in FIG. 9, in the case where it is determined to perform the normal control in the high rotation protection control determination in S300, 1 is added to the timer in S401 after the state flag F is set in S400. Here, although not shown, the timer is set to a predetermined time t by the initial value setting.

  If it is determined in S300 that the high rotation protection control is to be performed and the state flag is Fhi = 0, after setting the state flag F in S510, the timer value and t are set in S511. Compare the value with.

  If the timer value has passed the predetermined time t, the current evaporator temperature is set to the reference evaporator temperature TEhi in S520. If the timer value has not passed the predetermined time t, the previously set reference evaporator temperature TEhi is used to skip S520.

  After replacing the control current Iouthi (n) during the protection control operation with the control current Iout (n) in S560, the timer is initialized to 0 in S570.

  In this way, by using the timer that counts the elapsed time from the end of the high rotation protection control, when the high rotation protection control is activated again before the predetermined time t has elapsed, the reference evaporator temperature TEhi is cumulatively increased. Therefore, deterioration of the air conditioning feeling of the occupant can be suppressed.

  Although the predetermined time t is set as the initial value of the timer of the present embodiment, even if the high rotation protection control is activated within a predetermined time after the capacity control of the compressor 11 is started, This is to set the reference evaporator temperature immediately after the high rotation protection control operation without skipping S520 in the timer determination.

(Sixth embodiment)
A second embodiment of the present invention will be described based on FIG. 4, FIG. 5, and FIG. In the present embodiment, only the parts different from the first embodiment will be described. FIG. 10 shows a control map of the accelerator opening and the vehicle speed used for determining the control flag when the engine load is determined.

  This embodiment is different in that the high rotation protection control determination of S300 shown in FIG. 4 in the first embodiment is changed to engine load determination, and it is determined whether the vehicle engine load state is a high load state or a low load state. Yes. Here, the high load state indicates a state where the vehicle speed is small with respect to the accelerator opening, that is, a state where a vehicle acceleration request is made. The low load state indicates a state where the vehicle speed is large with respect to the accelerator opening.

  In the first embodiment, as shown in FIG. 5, it is determined whether or not the high rotation protection control is to be performed based on the rotation speed Nc (n) of the compressor 11 and the threshold value A. In this embodiment, the accelerator opening is detected by an accelerator opening sensor 45 as an accelerator opening detecting means, and the vehicle speed is detected by a vehicle speed sensor 44 as a vehicle speed detecting means. Here, the accelerator opening and the vehicle speed correspond to the engine load information in the present invention, and the accelerator opening sensor 45 and the vehicle speed sensor 44 correspond to the engine load detecting means in the present invention.

  The control flag F is determined based on the engine load information by the engine load detection means and the control map (FIG. 10) of the accelerator opening and the vehicle speed stored in advance in the ROM or the like of the air conditioning controller 30. In the present embodiment, the solid line in FIG. 10 (the line between the high load region and the low load region) indicates the reference vehicle speed with respect to the accelerator opening, and is high when the actual vehicle speed with respect to the accelerator opening is lower than the reference vehicle speed. Judged as a load state. Moreover, when the vehicle speed with respect to the accelerator opening exceeds the reference vehicle speed, it is determined that the load is low.

  Specifically, when the relationship between the accelerator opening and the vehicle speed is in a low load region (low load state) where the actual vehicle speed exceeds the reference vehicle speed with respect to the accelerator opening, the control flag in FIG. To decide. When the actual vehicle speed is lower than the reference vehicle speed with respect to the accelerator opening, the control flag is determined to be F = 1.

  When the control flag is F = 0 (low load state), the control current Iout is calculated by the normal control in FIG. 4 (S400 to S410). When the control flag is F = 1 (high load state), the control current Iout for reducing the capacity of the compressor 11 is calculated (S500 to S560).

  Thereby, the capacity | capacitance of the compressor 11 when the engine load of a vehicle will be in a high load state is reduced more reliably than when the engine load is in a high load state, and the consumption torque in the compressor 11 is reduced. Thus, while improving the acceleration performance of the vehicle, it is possible to suppress the deterioration of the air conditioning feeling due to the rise in the evaporator temperature caused by reducing the capacity of the compressor 11.

(Seventh embodiment)
A sixth embodiment of the present invention will be described based on FIG. 4, FIG. 10, and FIG. In the present embodiment, only parts different from the sixth embodiment will be described. FIG. 11 shows a control map of the accelerator opening and the vehicle speed used for determining the control flag when engine load determination is performed.

  This embodiment is different in the method for determining the control flag F in the engine load determination of FIG. 10 shown in the sixth embodiment.

  In the sixth embodiment, as shown in FIG. 10, the control map for determining the engine load determines the control flag F in two regions, a low load region and a high load region.

  However, generally, when the engine load state of the vehicle is in a high load state, the capacity control of the compressor 11 is performed so that the engine load state of the vehicle is either a high load state with priority on air conditioning or a high load state with priority on acceleration. It is determined whether or not there is a capacity control according to the engine load state. Specifically, in the high load state where air conditioning has priority, the capacity control of the compressor 11 is performed to reduce the capacity of the compressor 11 within a range in which air conditioning performance can be ensured. Further, in the high load state where acceleration is prioritized, the capacity control of the compressor 11 is performed so that the capacity of the compressor 11 is reduced regardless of the air conditioning performance in order to prioritize acceleration. Here, the high load state with priority on acceleration indicates a state in which the vehicle speed relative to the accelerator opening is larger than the vehicle speed in the high load state with priority on air conditioning. The high load state with priority on air conditioning indicates a state in which the vehicle speed relative to the accelerator opening is larger than the vehicle speed in the low load state and smaller than the vehicle speed in the high load state with priority on acceleration.

  Therefore, in this embodiment, the value of the control flag F is determined based on the accelerator opening and vehicle speed control map (FIG. 11) stored in advance in the ROM or the like of the air conditioning control device 30. In the present embodiment, the lower solid line in FIG. 11 (the line between the high load region with acceleration priority and the high load region with air conditioning priority) indicates the low load reference vehicle speed with respect to the accelerator opening, and the accelerator opening. When the actual vehicle speed with respect to exceeds the low-load reference vehicle speed, it is determined that the load is low. In addition, the upper solid line (the line between the high load area and the low load area where air conditioning has priority) indicates the high load reference vehicle speed with respect to the accelerator opening, and the actual vehicle speed with respect to the accelerator opening is lower than the high load reference vehicle speed. In this case, it is determined that the high load state has priority on acceleration. Further, when the vehicle speed relative to the accelerator opening exceeds the high load reference vehicle speed and falls below the low load reference vehicle speed, it is determined that the air load has a high load priority.

  Specifically, when the relationship between the accelerator opening and the vehicle speed is in a low load region (low load state) where the vehicle speed is large with respect to the accelerator opening, the control flag is determined to be F = 0. When the vehicle speed with respect to the accelerator opening is larger than that in the low load state and is in a high load region with priority on air conditioning smaller than a predetermined value, the control flag is determined to be F = 1. When the vehicle speed with respect to the accelerator opening is in a high load region with acceleration priority greater than a predetermined value in the high load state with air conditioning priority, the control flag is determined to be F = 2.

  When the control flag is F = 0, the control current Iout is calculated by the normal control in FIG. 4 (S400 to S410). When the control flag is F = 1, the control current Iout for reducing the capacity of the compressor 11 is calculated (S500 to S560).

  Further, when the control flag is F = 2, the capacity control of the compressor 11 in a high load state in which acceleration is prioritized is performed. Note that the capacity control method of the compressor 11 giving priority to acceleration is such that when the engine load state is a high load state, the compressor 11 is stopped for a short time and thereafter the capacity is gradually restored. For example, the control described in JP-A-2004-182192 can be performed.

  Thereby, even if it is a case where capacity control of compressor 11 is carried out in the engine high load state of acceleration priority and air conditioning priority, the present invention can be applied in the high load state of air conditioning priority.

(Eighth embodiment)
An eighth embodiment of the present invention will be described with reference to FIGS. In the present embodiment, only the parts different from the first embodiment will be described. FIG. 12 shows a control current calculation method when an electromagnetic pressure control device is used for the variable capacity device 11b, and FIG. 13 is a flowchart showing a control current calculation process in the present embodiment.

  In the first embodiment, the control current Iout of the capacity variable device 11b is calculated by proportional integral control (PI control) based on the deviation E between the target evaporator temperature TEO and the evaporator temperature TE in S410 or S550 in FIG. Yes.

  In the first embodiment, since the variable capacity device 11b includes an electromagnetic pressure control device, in the present embodiment, the target suction pressure Pso corresponding to the target evaporator temperature TEO is calculated, and the capacity is calculated based on the target suction pressure Pso. A method for calculating the control current Iteo of the variable device 11b will be described.

  A method for calculating the control current Iteo of the variable capacity device 11b based on the target suction pressure Pso will be described with reference to FIG. FIG. 12A shows the relationship between the control current Iteo and the target suction pressure Pso of the variable capacity device 11b. FIG. 12B shows the relationship between the temperature of the saturated refrigerant in the evaporator 9 and the pressure in the evaporator 9. Here, since the state of the refrigerant in the evaporator 9 is a gas-liquid two-layer saturated refrigerant, the relationship between the temperature and pressure of the saturated refrigerant shown in FIG.

  First, the evaporator temperature TE is detected from the evaporator temperature sensor 34. The evaporator pressure Pte can be estimated from the detected evaporator temperature TE and the relationship between the temperature and pressure of the saturated refrigerant shown in FIG.

  Further, the control current Iout (n−1) of the variable capacity device 11b when the evaporator temperature TE is detected is detected. Based on the detected control current Iout (n−1) and the relationship between the control current shown in FIG. 12A and the suction target suction pressure, the current suction pressure Ps of the compressor 11 can be estimated.

  Since the evaporator 9 and the compressor 11 are connected by refrigerant piping, it is necessary to consider the pressure loss in the refrigerant piping. The pressure loss in the refrigerant pipe between the evaporator 9 and the compressor 11 can be estimated as ΔP obtained by subtracting the suction pressure Ps from the refrigerant pressure Pte.

  Here, although the value of the pressure loss ΔP differs depending on the operating state of the air conditioner, when the evaporator temperature TE is changed to the target evaporator temperature TEO under the same conditions, the values of the evaporator temperature TE and the target evaporator temperature TEO are changed. If there is no large difference, it can be considered that there is almost no change in pressure loss in the refrigerant piping.

  Therefore, the target suction pressure Pso at the target evaporator temperature TEO is obtained from the target evaporator pressure Pteo in the evaporator 9 estimated from the relationship between the target evaporator temperature TEO and the saturated refrigerant temperature and pressure shown in FIG. It can be calculated as a pressure reduced by the pressure loss. Based on the calculated target suction pressure Pso and the relationship between the control current and the target suction pressure shown in FIG. 12A, the control current Iout corresponding to the target evaporator temperature can be calculated. Thereby, the control current Iout can be calculated from the target evaporator temperature TEO.

  Next, based on FIG. 13, the high rotation protection control of the variable capacity device 11b having the electromagnetic pressure adjusting device will be described using the calculation method of the control current Iout of the variable capacity device 11b.

  In this embodiment, the calculation method (S500 to S560) of the control current Iout in the first embodiment shown in FIG. 4 is replaced with the calculation method (S500 to S660) of the control current Ithi of the variable capacity device 11b shown in FIG. Is.

  First, in S100, the temperature deviation E is calculated by subtracting the first target evaporator temperature TEO1 from the evaporator temperature TE. In S200, the compressor rotational speed Nc (n) is calculated. Next, in S300, it is determined whether or not to implement the compressor rotation speed Nc (n) and high rotation protection control.

  When the control flag is F = 0, the control current Iout is calculated by the normal control in FIG. 1 (S400 to S410).

  If it is determined in S300 that the control flag F = 1, that is, if the high-rotation protection control is to be performed, it is determined in S500 whether the protection control operation is in progress or not based on the value of the state flag Fhi indicating the operation state of the protection control. .

  When the state flag indicating the operation state of the protection control is Fhi = 0, it can be determined immediately after switching from the normal control to the high rotation protection control, so the state flag Fhi = 1 is set in S510.

  In S520, in order to hold the evaporator temperature TE immediately after the protection control operation, the value of the evaporator temperature TE is stored in the reference evaporator temperature TEhi immediately after the protection control operation. In order to hold the control current of the variable capacity device 11b immediately after the protection control operation, in S521, the value of Iout (n−1) is substituted for Itout and recorded.

  Further, when the state flag Fhi = 1, it can be determined that the protection control operation is being performed (the second and subsequent protection control operations), so S510 to S521 are skipped.

  In S530, the second target evaporator temperature TEO2 is calculated by adding the allowable increase temperature ΔT that can be allowed by the air conditioning feeling to the reference evaporator temperature TEhi immediately after the high rotation protection control operation.

  Next, in S600, the evaporator pressure Pte is calculated from the reference evaporator temperature TEhi based on the temperature-pressure characteristics (FIG. 12B) of the saturated refrigerant stored in advance in the ROM or the like of the air conditioning control device 30.

  In S610, based on the control current-target suction pressure characteristic (FIG. 12A) of the variable capacity device 11b stored in advance in the ROM or the like of the air conditioning control device 30, the control current Itout of the variable capacity device 11b recorded in S521. Thus, the suction pressure Ps of the compressor 11 is calculated.

  In S620, the pressure loss ΔP in the refrigerant pipe is calculated by subtracting the suction pressure Ps calculated in S610 from the evaporator pressure Pte calculated in S600. Here, the pressure loss ΔP in the refrigerant pipe does not theoretically become a negative value. If the pressure loss ΔP becomes a negative value, it is considered that an abnormal value is calculated because the operation of the air conditioner is in a transient state. Therefore, if the value of the pressure loss ΔP becomes negative, a treatment for setting the value of the pressure loss ΔP to 0 may be performed as an abnormal value treatment.

  In S630, the target evaporator pressure Pteo at the second target evaporator temperature TEO2 is calculated based on the characteristics of the evaporator temperature of the saturated refrigerant and the evaporator pressure.

  In S640, the target suction pressure Pso is calculated by subtracting the pressure loss ΔP in the refrigerant pipe from the target evaporator pressure Pteo.

  In S650, the control current Iteohi of the capacity variable device 11b is calculated based on the characteristic of the control current of the capacity variable device 11b and the target suction pressure.

  In S660, the control current Iteohi of the variable capacity device 11b is substituted for the control value Iout (n) of the compressor 11.

  As described above, when the variable capacity device 11b includes the electromagnetic pressure control device, as shown in the present embodiment, the target suction pressure Pso corresponding to the target evaporator temperature TEO is calculated, and the target suction pressure Pso is calculated. Thus, the control current Iout of the variable capacity device 11b can be calculated.

(Ninth embodiment)
A ninth embodiment of the present invention will be described with reference to FIG. In the present embodiment, only different parts from the eighth embodiment will be described. FIG. 14 is a flowchart showing control current calculation processing in the present embodiment.

  In the eighth embodiment, the pressure loss ΔP in the refrigerant pipe between the evaporator 9 and the compressor 11 is equal to the pressure in the refrigerant pipe unless there is a large difference between the values of the evaporator temperature TE and the second target evaporator temperature TEO2. Since it can be considered that there is almost no change in the loss ΔP, the value is fixed. In the eighth embodiment, during normal control, the control current is calculated by proportional-integral control (PI control) based on the deviation En between the first target evaporator temperature TEO1 and the evaporator temperature TE.

  In the present embodiment, the pressure loss ΔP is calculated from the detected evaporator temperature TE (n) and the control current Iout (n−1) at that time. That is, during the high rotation protection control operation, the change in the pressure loss of the refrigerant pipe due to the change in the operating state of the air conditioner is updated every time as ΔP (n), and the control current Iout (n) of the variable capacity device 11b is calculated every time. And output. Also during normal control, the target suction pressure Pso corresponding to the first target evaporator temperature TEO1 is calculated, and the control current Iout of the variable capacity device 11b corresponding to the target suction pressure Pso is calculated.

  Next, based on FIG. 14, the high rotation protection control of the variable capacity device 11b having the electromagnetic pressure adjusting device will be described using the calculation method of the control current Iout of the variable capacity device 11b.

  First, the compressor rotational speed Nc (n) is calculated in S200.

  Next, in S300, it is determined whether or not to implement the compressor rotation speed Nc (n) and high rotation protection control.

  In S400, if it is determined in S300 that the control flag F = 0, that is, the normal control is to be performed, the state flag Fhi = 0 indicating the operating state of the high rotation protection control is set.

  In S420, the first target evaporator temperature TEO1 is stored in the target evaporator temperature TEOx.

  Next, in S700, the evaporator pressure Pte (n) is calculated from the evaporator temperature TE (n) based on the temperature-pressure characteristics of the saturated refrigerant.

  In S710, the suction pressure Ps (n) of the compressor 11 is calculated from the control current Iout (n-1) of the capacity variable device 11b based on the control current-control suction pressure characteristic of the capacity variable device 11b of the compressor 11. .

  In S720, the suction pressure Ps (n) calculated in S710 is subtracted from the evaporator pressure Pte (n) calculated in S700 to calculate the pressure loss ΔP (n) in the refrigerant pipe.

  Thereafter, in S730, the evaporator pressure Pteo at the target evaporator temperature TEOx is calculated based on the temperature-pressure characteristics of the saturated refrigerant.

  In S740, the target suction pressure Pso (n) is calculated by subtracting the pressure loss ΔP in the refrigerant pipe from the evaporator pressure Pteo.

  In S750, the control current Iout (n) of the variable capacity device 11b is calculated using the control current-suction pressure characteristic of the variable capacity device 11b.

  If it is determined in S300 that the control flag F = 1, that is, that the high-rotation protection control is to be performed, it is determined in S500 whether the protection control operation is in progress or not based on the value of the state flag Fhi indicating the operation state of the protection control.

  When the state flag indicating the operation state of the protection control is Fhi = 0, it can be determined immediately after switching from the normal control to the high rotation protection control, so the state flag Fhi = 1 is set in S510. In order to hold the evaporator temperature immediately after the protection control operation, the value of the evaporator temperature TE (n) is substituted into the reference evaporator temperature TEhi immediately after the protection control operation in S520.

  Further, when the state flag indicating the protection control operation state is Fhi = 1, it can be determined that the protection control operation is being performed (the second and subsequent protection control operations), so S510 and S520 are skipped.

  In S530, the second target evaporator temperature TEO2 during the protection control operation is calculated by adding the allowable increase temperature ΔT that can be allowed by the air conditioning feeling to the reference evaporator temperature TEhi immediately after the high rotation protection control operation.

  In S580, the second target evaporator temperature TEO2 calculated in S530 is stored in the target evaporator temperature TEOx. Thereafter, the control current is calculated in the same manner as in the normal control (S700 to S750).

  Thus, compared with the eighth embodiment, in this embodiment, the pressure loss ΔP (n) in the refrigerant pipe is updated every time and the control current Iout of the variable capacity device 11b is calculated and output every time. The purpose of correcting the deviation between the target evaporator temperature TEO and the evaporator temperature TE, reducing the capacity of the compressor 11, and suppressing the deterioration of the air conditioning feeling of the occupant can be achieved more accurately. Further, since the control can be configured by the same capacity control method of the compressor 11 both during the normal control and during the high rotation protection control, the control current calculation process can be simplified.

(Other embodiments)
In each of the above embodiments, a variable displacement compressor is used as the compressor 11. As the variable displacement compressor, the target suction pressure Pso of the suction pressure Ps is set by the control current Iout of the displacement variable device 11b as shown in FIG. A system (suction pressure control system) is used that increases and decreases the discharge capacity so that the suction pressure Ps is maintained at the target suction pressure Pso. However, the first to seventh embodiments are not limited to the suction pressure control system, and the target displacement of the discharge flow rate of the compressor 11 as shown in FIG. A flow rate Gro can be set to increase or decrease the discharge capacity so that the discharge flow rate of the compressor 11 is maintained at the target discharge flow rate Gro (discharge flow rate control method). More specifically, in the variable displacement compressor of the discharge flow rate control system, a throttle portion is provided on the discharge side, and the differential pressure generated before and after the throttle portion is proportional to the discharge flow rate. Therefore, if the discharge capacity is increased or decreased so that the differential pressure before and after the throttle becomes the target differential pressure, the discharge flow rate of the compressor 11 is maintained at the target discharge flow rate Gro. Note that a variable displacement compressor using a discharge flow rate control method is known from Japanese Patent Application Laid-Open No. 2001-107854.

  Further, in the first embodiment, the third to fifth embodiments, and the eighth and ninth embodiments, the high-rotation protection control determination is performed based on FIG. 5, but is shown in FIG. 6 applied in the second embodiment. You may process based on high-rotation protection control determination.

  In each of the above embodiments, except for the third embodiment, the allowable rise temperature is a fixed value. However, the allowable rise temperature may be set using the control maps shown in FIGS.

  In each of the above embodiments, the timer determination process (FIG. 7, S511) is not performed except in the fourth embodiment. However, the timer determination process may be performed not only in the fourth embodiment but also in other embodiments. .

  Further, in the sixth and seventh embodiments, the control flag is determined based on the accelerator opening and vehicle speed control map shown in FIG. 10 or FIG. 11, but the control flag is limited to the accelerator opening and vehicle speed control map. Instead, for example, a control map of throttle opening and vehicle speed detected by a throttle opening sensor may be used. Here, the throttle opening sensor is for detecting the throttle opening of the engine E and obtaining the intake air amount of the engine E based on the obtained throttle opening.

It is a general | schematic system block diagram of the vehicle air conditioner which shows 1st Embodiment of this invention. It is a control characteristic figure which shows the relationship between the target suction pressure of a compressor, and control current. It is a flowchart which shows the outline of the whole capacity control of a variable capacity type compressor. The flowchart of the control current calculation process which the air-conditioning control apparatus in 1st Embodiment performs is shown. It is a control characteristic figure which shows the relationship between a control flag and compressor rotation speed. It is a control characteristic figure which shows the relationship between a control flag and compressor rotation speed. It is a control characteristic figure which shows the relationship between an evaporator temperature rise amount and target blowing temperature. It is a control characteristic figure which shows the relationship between an evaporator temperature rise amount and compressor rotation speed. The flowchart of the control current calculation process which the air-conditioning control apparatus in 5th Embodiment performs is shown. It is a control characteristic figure which shows the relationship between an accelerator opening and a vehicle speed. It is a control characteristic figure which shows the relationship between an accelerator opening and a vehicle speed. It is a control characteristic figure used by control current calculation processing which an air-conditioning control device in an 8th embodiment performs. The flowchart of the control current calculation process which the air-conditioning control apparatus in 8th Embodiment performs is shown. The flowchart of the control current calculation process which the air-conditioning control apparatus in 9th Embodiment performs is shown. It is a control characteristic figure which shows the relationship between the target discharge flow rate of a compressor, and control current.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Indoor air-conditioning unit, 9 ... Evaporator, 10 ... Refrigeration cycle apparatus, 11 ... Compressor, 11b ... Variable capacity apparatus, 34 ... Evaporator temperature sensor.

Claims (5)

A compressor (11) driven by the engine E of the vehicle and capable of changing the discharge capacity of the refrigerant;
An evaporator (9) connected to the refrigerant suction side of the compressor (11) and evaporating the refrigerant to cool the air flowing through the passenger compartment;
Temperature detecting means (34) for detecting an evaporator temperature TE which is a temperature of air after passing through the evaporator (9);
Capacity control means (11b) for controlling the refrigerant discharge capacity of the compressor (11) so that the evaporator temperature TE becomes the target evaporator temperature TEO;
A vehicle air conditioner comprising: a rotation speed detecting means for detecting a rotation speed Nc of the compressor (11);
When the rotation speed of the compressor (11) exceeds a predetermined rotation speed, the capacity control means (11b) causes the evaporation when the rotation speed of the compressor (11) exceeds the predetermined rotation speed. A vehicle air conditioner characterized in that a value obtained by adding a preset allowable rise temperature ΔT to the evaporator temperature is set as the target evaporator temperature. Engine load detection means for detecting engine load information of the vehicle;
Engine load determination means for determining a load state of the engine based on the engine load information,
When the engine load determining means determines that the engine is in a high load state, the capacity control means adds the preset allowable increase temperature ΔT to the evaporator temperature when it is determined to be in the high load state. The vehicle air conditioner according to claim 1, wherein the measured value is set as the target evaporator temperature. The capacity control means (11b) controls the discharge capacity of the refrigerant by controlling the suction pressure Ps of the compressor (11) so that the evaporator temperature becomes the target evaporator temperature. The vehicle air conditioner according to claim 1 or 2. The capacity control means (11b) decreases the allowable increase temperature ΔT as the difference between the target blowing temperature TAO of the air blown into the passenger compartment and the evaporator temperature increases, and the target blowing temperature TAO and the evaporator The vehicle air conditioner according to any one of claims 1 to 3, wherein the allowable increase temperature ΔT is increased as the difference from the temperature is decreased. The capacity control means (11b) sets the evaporator temperature increase ΔT so that the allowable increase temperature ΔT increases as the rotation speed of the compressor (11) increases, and the rotation speed of the compressor (11) increases. The vehicle air conditioner according to any one of claims 1 to 3, wherein the allowable increase temperature ΔT is reduced as the value becomes smaller.

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