JP2004182192A - Method for controlling air conditioner for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure comfortableness of an occupant within a cabin by suppressing lowering of cooling capacity as much as possible at the time of accelerating a vehicle, in an air conditioner for the vehicle. <P>SOLUTION: When a degree of acceleration is a degree in which acceleration may be cut when accelerating the vehicle, load (torque) of a compressor is controlled according to cooling capacity required for the air conditioner. By the control, the acceleration is at least partially cut. When the acceleration can not be cut because the degree of acceleration is high or when cooling capacity is left in the air conditioner, the load of the compressor is once reduced and torque of an engine for the vehicle is assigned to accelerate the vehicle. Even in the case, the reduced load of the compressor is gradually returned to secure cooling capacity as much as possible. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control method of a vehicle air conditioner at the time of vehicle acceleration.
[0002]
[Prior art]
In a vehicle air conditioner equipped with a refrigerant compressor driven by a vehicle engine, the compressor of the air conditioner does not hinder the acceleration of the vehicle when the vehicle is accelerating, and the cooling capacity of the air conditioner also increases. It is desirable to secure.
[0003]
In this regard, Patent Literature 1 below requires that the vehicle be accelerated using a control map determined by the throttle opening and the vehicle speed (that is, the vehicle is within an acceleration request range in the control map). A control method for shutting down the compressor for a predetermined time when it is determined is disclosed.
[0004]
[Patent Document 1]
JP-A-62-2820
[0005]
However, the control method described in Patent Document 1 simply stops driving of the compressor when the vehicle is required to accelerate (the vehicle is within an acceleration request range in the control map). Although the acceleration of the vehicle is improved, it is difficult to secure the cooling capacity of the vehicle air conditioner.
[0006]
In order to solve this problem, in the vehicle air conditioner described in Patent Literature 2 below, the maximum acceleration at which the occupant feels acceleration of the vehicle when the vehicle accelerates occurs in a short time immediately after the acceleration starts, and Focusing on the fact that if the refrigerant circulates in the refrigeration cycle of the air conditioner even at a relatively small flow rate, it is possible to suppress the rise in the temperature of the air blown out of the air conditioner. Thereafter, the capacity is gradually restored by the partial capacity operation, thereby trying to achieve both the acceleration of the vehicle and the cooling capacity.
[0007]
[Patent Document 2]
JP 2000-335232 A
[0008]
However, in the air conditioner described in Patent Literature 2, control is not performed according to the degree of acceleration of the vehicle, and the compressor is similarly operated regardless of whether it is sudden acceleration or gentle acceleration (slow acceleration). And then the capacity control is performed. Therefore, at the time of gentle acceleration with a small degree of acceleration, there is a problem that the amount of reduction in cooling capacity is large for a small acceleration effect, and a cooling capacity in a possible range corresponding to the degree of acceleration is not secured.
[0009]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to secure the acceleration performance of a vehicle when the vehicle is accelerating, and to ensure the cooling capacity corresponding to the degree of acceleration of the vehicle. An object of the present invention is to provide a control method of a vehicle air conditioner.
[0010]
[Means for Solving the Problems]
The present invention provides, as means for solving the above-mentioned problems, a control method of a vehicle air conditioner described in claim 1 of the claims. According to a first aspect of the present invention, in the control method of a vehicle air conditioner including a variable capacity refrigerant compressor driven by a vehicle engine, it is determined whether or not the acceleration cut can be performed based on a degree of acceleration of the vehicle. And comparing the cooling capacity remaining in the air conditioner with the cooling capacity required at that time, and the degree of acceleration of the vehicle is higher than a predetermined level at which acceleration can be cut, and the cooling remaining in the air conditioner is performed. When it is determined that the capacity exceeds the required cooling capacity at that time, a step of controlling the load of the compressor according to a pattern of once reducing the load on the compressor to the engine and then gradually returning the load to the engine; Sometimes controlling the compressor according to the cooling capacity required at that time.
[0011]
Accordingly, when the degree of acceleration of the vehicle is lower than a predetermined level at which the acceleration may be cut, securing of the cooling capacity of the air conditioner is prioritized over securing of the acceleration of the vehicle, and the load on the air conditioner is reduced. It is controlled according to the required cooling capacity as usual. When the degree of acceleration of the vehicle is higher than a predetermined level at which acceleration can be cut, if the cooling capacity remaining in the air conditioner at that time exceeds the cooling capacity required at that time, the compressor The load of the compressor is temporarily reduced, and the corresponding torque is diverted to accelerate the vehicle. Thereafter, the load on the compressor is gradually increased to restore the cooling capacity. Even when the cooling capacity remaining in the air conditioner is lower than the cooling capacity required at that time, priority is also given to securing the cooling capacity.
[0012]
The present invention also provides, as another means for solving the above problems, a control method of a vehicle air conditioner described in claim 2 of the claims. According to a second aspect of the present invention, in the control method for a vehicle air conditioner including a variable displacement refrigerant compressor driven by a vehicle engine, it is determined whether or not the acceleration cut can be performed based on the degree of acceleration of the vehicle. And when the degree of acceleration of the vehicle is determined not to be in the region where the acceleration can be cut, the load on the compressor is controlled according to a pattern in which the load on the compressor on the engine is temporarily reduced and then gradually restored. Calculating the load reduction amount and the return time of the compressor according to the degree of acceleration of the vehicle, and performing compression according to the cooling capacity remaining in the air conditioner for controlling the load of the compressor according to the pattern. Calculating a load reduction amount and a return time of the machine; comparing the calculated two load reduction amounts and the two return times to select a minimum value; A step of performing a load control of the compressor in accordance with the pattern by reducing the amount and the return time, when the other and a step of controlling in accordance with the cooling capacity required of the compressor at that time.
[0013]
Thus, when the degree of acceleration of the vehicle is in a region where partial or accelerated cutting may be performed, securing of the cooling capacity of the air conditioner is given priority over securing of the acceleration of the vehicle, and compression of the air conditioner is reduced. The load on the machine is controlled as usual, depending on the cooling capacity required at that time. When the degree of acceleration of the vehicle is higher than a predetermined level and it is in an area where it is not possible to cut the acceleration, the load on the compressor is temporarily reduced, and the corresponding torque is diverted to accelerate the vehicle. However, thereafter, the load on the compressor is gradually increased to restore the cooling capacity. In this case, the load reduction amount and the return time of the compressor are calculated based on the degree of acceleration of the vehicle and calculated based on the cooling capacity remaining in the air conditioner, and compared. The value is selected, and load control of the compressor is performed.
[0014]
In any case, in a state where the vehicle may be cut to accelerate, securing the cooling capacity of the air conditioner has priority over securing the acceleration of the vehicle, so even during acceleration. By allocating torque for acceleration to the compressor as much as possible and securing the cooling capacity of the air conditioner, the comfort of the occupant can be improved. If the degree of acceleration is so high that the acceleration cut cannot be performed, or if the air conditioner has sufficient cooling capacity, the load on the compressor is reduced once by a necessary amount and the vehicle engine Is applied to improve the acceleration of the vehicle, but even in such a case, the load on the compressor is gradually returned to ensure the cooling capacity as much as possible.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a vehicle air conditioner to which a control method of the present invention is applied will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of an entire system of a vehicle air conditioner including a refrigeration cycle 1. The refrigeration cycle 1 is provided with a variable displacement compressor 2 that sucks, compresses, and discharges refrigerant. The high-temperature, high-pressure superheated gas refrigerant discharged from the compressor 2 flows into the condenser 3, where it exchanges heat with the outside air blown by a cooling fan (not shown), so that the refrigerant is cooled and condensed.
[0016]
The refrigerant condensed in the condenser 3 then flows into a liquid receiver (gas-liquid separator) 4, where the gas part and the liquid part of the refrigerant are separated inside the liquid receiver 4, and the refrigeration cycle of the air conditioner for a vehicle. The surplus refrigerant (liquid refrigerant) in 1 is stored in the liquid receiver 4. The liquid refrigerant from the liquid receiver 4 is decompressed to a low pressure by the expansion valve (decompression means) 5, and enters a gas-liquid two-phase state. The low-pressure refrigerant from the expansion valve 5 flows into the evaporator 6. The evaporator 6 is installed in an air conditioning case 7 constituting an air passage of the vehicle air conditioner. The low-pressure refrigerant flowing into the evaporator 6 absorbs heat from the air in the air conditioning case 7 and evaporates.
[0017]
The expansion valve 5 is a temperature-type expansion valve having a temperature sensing portion 5a for sensing the temperature of the refrigerant at the outlet of the evaporator 6, and has a valve opening (refrigerant) that maintains the superheat of the refrigerant at the outlet of the evaporator 6 at a predetermined value. Flow rate). The above cycle components (2 to 6) are connected by a refrigerant pipe 8 to form a closed circuit.
[0018]
The compressor 2 is driven by a vehicle traveling engine (E / G) 11 via a power transmission mechanism 9, a belt 10, and the like. The compressor 2 is a variable displacement compressor having a structure as described below. In the air conditioner of the illustrated embodiment, the power transmission mechanism 9 is a clutch mechanism (for example, an electromagnetic clutch) that can select transmission / disconnection of power by external electric control. A power transmission type clutchless mechanism that is not provided and is always available.
[0019]
A blower 12 is provided in the air-conditioning case 7, and air in the vehicle compartment (inside air) or air outside the vehicle (outside air) sucked from a well-known inside / outside air switching box (not shown) is blown by the blower 12. The air is blown into the passenger compartment. After passing through the evaporator 6, the blown air passes through a heater unit (not shown) and is blown out from the outlet into the vehicle interior.
[0020]
In the air conditioning case 7, an evaporator outlet temperature sensor 13 composed of a thermistor for detecting the temperature of the blown air immediately after passing through the evaporator 6 is provided at a position immediately downstream of the evaporator 6.
[0021]
The heater unit is a well-known type, and includes a hot water heater core (heating means) for reheating cold air passing through the evaporator 6, and an air mixing door serving as a temperature adjusting means for adjusting the degree of heating in the hot water heater core. Alternatively, a hot water flow control valve or the like is provided, and at the downstream end of the air conditioning case 7, a face outlet for blowing air to the upper body of an occupant in the cabin, and a foot outlet for blowing air to the feet of the occupant of the cabin. A defroster outlet for blowing air is formed on the inner surface of the windshield, and an outlet mode door for switching and opening these outlets is provided.
[0022]
The compressor 2 has an electromagnetic displacement control valve (discharge displacement control mechanism) 15 controlled by an electric signal from an air-conditioning control device (A / C ECU) 14. The control valve 15 controls the control pressure. Since the compressor 2 can be changed, the compressor 2 is an external variable displacement compressor. A detection signal of a sensor group 16 for automatic control of air conditioning and an operation signal of an operation switch group of an air conditioning operation panel 17 are input to the air conditioning control device 14.
[0023]
Note that the sensor group 16 is specifically an inside air sensor, an outside air sensor, a solar radiation sensor, an engine water temperature sensor, and the like. The operation switch group of the air conditioning operation panel 17 is specifically a temperature setting switch, an air volume changeover switch, A blow mode switch, an inside / outside air switch, an air conditioner switch for issuing an operation command for the compressor 2, and the like.
[0024]
Further, in the refrigeration cycle 1, a high-pressure sensor 18 for detecting the high-pressure pressure of the refrigerant (compressor discharge pressure) is provided in a high-pressure circuit section from the discharge side of the compressor 2 to the inlet of the expansion valve 5. The detection signal 18 is also input to the air-conditioning control device 14. In the illustrated example, the high-pressure sensor 18 is provided in the refrigerant pipe on the outlet side of the condenser 3.
[0025]
Further, the air-conditioning control device 14 is connected to an engine control device (E / G ECU) 19 on the vehicle side, so that signals can be input and output between the two control devices 14 and 19. As is well known, the engine control device 19 comprehensively controls a fuel injection amount, an ignition timing, and the like to the vehicle engine 11 based on a signal or the like from a sensor group 19a for detecting an operation state and the like of the vehicle engine 11. It is.
[0026]
In the air conditioner of the illustrated embodiment, information such as the engine speed, vehicle speed, throttle opening or accelerator opening provided from the engine control device 19 is transmitted to the air conditioning control device 14, and the acceleration degree is determined as described later. It is used for determination and calculation of compressor load (torque).
[0027]
FIG. 2 is a sectional view showing the structure of the external variable displacement compressor 2 used in the air conditioner of the illustrated embodiment. In the compressor 2, a target flow rate Gro of the compressor discharge flow rate is set by the control current (ie, control current signal) In of the electromagnetic displacement control valve 15, and the compressor discharge flow rate is maintained at the target flow rate Gro. The discharge capacity is increased or decreased (discharge amount control type). Specifically, the control current In increases in proportion to the increase in the target flow rate Gro.
[0028]
As shown in FIG. 2, the compressor 2 is a single-swash plate type variable displacement compressor, and the variable displacement mechanism itself is well known. The power of the vehicle engine 11 is transmitted to the rotating shaft 20 via the power transmission mechanism 9 and the like in FIG. The left end of the rotation shaft 20 in FIG. 2 is a connection portion with the power transmission mechanism 9. A swash plate 21 is integrally rotatably connected to the rotating shaft 20, and the inclination angle of the swash plate 21 can be adjusted by a hinge mechanism 22 having a spherical head. Note that the solid line position of the swash plate 21 indicates a state where the inclination angle is small (small capacity state), and the two-dot chain line position 21a indicates a state where the inclination angle is large (large capacity state).
[0029]
A plurality of (for example, five) pistons 24 are connected to the swash plate 21 via shoes 23. For this reason, by rotating the swash plate 21 together with the rotating shaft 20, the plurality of pistons 24 are sequentially reciprocated via the shoes 23, and the volume of the cylinder chamber (working chamber) Vc is enlarged and reduced, so that the refrigerant is reduced. It is designed to be inhaled and compressed.
[0030]
When changing the discharge capacity of the compressor 2, the inclination angle of the swash plate 21 is changed by changing the pressure Pc in a crank chamber (swash plate chamber) 25 in which the swash plate 21 is housed, so that the piston 24 Change the stroke (stroke). That is, as the inclination angle of the swash plate 21 increases, the piston stroke increases and the discharge capacity increases, and as the inclination angle of the swash plate 21 decreases, the piston stroke decreases and the discharge capacity decreases.
[0031]
Therefore, the crank chamber 25 also serves as a control pressure chamber for changing the displacement of the compressor 2. The crank chamber (swash plate chamber) 25 communicates with the suction chamber 27 of the compressor 20 via a throttle passage 26.
[0032]
On the other hand, a first discharge chamber 29 and a second discharge chamber 30 are formed in a rear housing 28 of the compressor 20, and the first discharge chamber 29 is connected via a throttle communication passage (throttle portion) 31 having a predetermined throttle hole diameter. It communicates with the second discharge chamber 30. Refrigerant discharged from the working chamber (cylinder chamber) Vc of each piston 24 flows into the first discharge chamber 29 via the discharge port 33 and the discharge valve 34 of the valve plate 32 and merges to smooth discharge pulsation. You. The second discharge chamber 30 is connected to an external refrigerant discharge pipe via a discharge port 35.
[0033]
Further, the rear housing 28 is provided with a suction port 36 for sucking the low-pressure gas refrigerant from the outlet of the evaporator 6 and a suction chamber 27 into which the refrigerant flows from the suction port 36. Refrigerant is sucked from the suction chamber 27 into the working chamber Vc via the suction port 37 of the valve plate 32 and the suction valve 38.
[0034]
Since a pressure loss occurs when the refrigerant flows from the first discharge chamber 29 toward the second discharge chamber 30 through the throttle communication passage 31, the pressure Pd in the second discharge chamber 30 is reduced. _L Is the pressure Pd in the first discharge chamber 29 _H Lower by a predetermined amount ΔP. The pressure difference ΔP around the throttle communication passage 31 has a magnitude corresponding to the flow rate of the refrigerant discharged from the compressor.
[0035]
The electromagnetic displacement control valve 15 constitutes a discharge displacement control mechanism for controlling the pressure Pc in the crank chamber 25 forming a control pressure chamber, and is arranged on the rear housing 28 side of the compressor 2. Next, a specific configuration example of the displacement control valve 15 will be described. The control valve 15 has a pressure Pd in the first discharge chamber 29. _H And the pressure Pd in the first control chamber 40 and the second discharge chamber 30 which are guided through the communication passage 39. _L Is provided through a communication passage 41. The two control chambers 40 and 42 are partitioned by a slidable cylindrical member 43. Thus, a force due to the pressure difference ΔP between the control chambers 40 and 42 acts on one end of the push rod 44 via the cylindrical member 43 and the like as a force in the valve opening direction.
[0036]
Further, the pressure Pd in the first discharge chamber 29 _H A control pressure chamber 47 communicating with the crank chamber 25 through a communication passage 46 is provided in the control valve 15, and the control pressure chamber 47 is provided between the discharge pressure chamber 45 and the control pressure chamber 47. The pressure in the control pressure chamber 47, that is, the pressure in the crank chamber 25 (control pressure) is adjusted by adjusting the cross-sectional area of the opening of the throttle passage 48 by the position of the valve element 49 of the push rod 44. Pc can be adjusted.
[0037]
On the other hand, the electromagnetic mechanism 50 of the control valve 15 acts on the valve body 49 (push rod 44) with a force opposing the valve opening force due to the differential pressure ΔP, that is, the valve closing force. For this purpose, the valve element 49 is integrally connected to a plunger (movable iron core) 51 of the electromagnetic mechanism 50, and an electromagnetic attractive force induced by the exciting coil 52 acts on the plunger 51. That is, the plunger 51 is disposed so as to face the fixed magnetic pole member (fixed iron core) 53 at a predetermined interval, and the plunger 51 is axially moved toward the fixed magnetic pole member 53 by the electromagnetic attraction force induced by the exciting coil 52. In the direction (upward in FIG. 2). The valve body 49 moves in the valve closing direction due to the axial displacement of the plunger 51.
[0038]
A coil spring 54 is arranged between the plunger 51 and the fixed magnetic pole member 53 as elastic means for generating an elastic force that opposes the electromagnetic force.
[0039]
In this example, by controlling a control current (control current signal) In that flows through the excitation coil 52 (for example, by controlling a duty ratio Dt that is an intermittent ratio of the control current In), a desired electromagnetic attraction force ( That is, the force in the valve closing direction of the valve element 49) can be applied to the plunger 51. The control current In of the exciting coil 52 is controlled by the air conditioning controller 14 described above.
[0040]
Since the electromagnetic capacity control valve 15 is configured as described above, when the control current In is controlled to increase the valve closing force of the valve body 49, the valve body 49 is displaced upward in FIG. Since the opening cross-sectional area of the passage 48 is reduced, the pressure of the control pressure chamber 47, that is, the pressure Pc of the crank chamber 25 decreases, and the inclination angle of the swash plate 21 increases as shown by the two-dot chain line 21a in FIG. Thereby, the discharge capacity of the compressor 2 increases.
[0041]
Conversely, when the control current In is controlled to decrease the valve closing force of the valve element 49, the valve element 49 is displaced downward in FIG. As a result, the pressure in the control pressure chamber 47, that is, the pressure Pc in the crank chamber 25 increases, and the inclination angle of the swash plate 21 decreases as shown by the solid line in FIG. 2, thereby reducing the discharge capacity of the compressor 2. I do.
[0042]
On the other hand, when the number of revolutions of the engine 11 increases and the number of revolutions of the compressor 2 increases, the flow rate of the discharged refrigerant discharged from the compressor 2 increases in conjunction with the increase. Since the pressure difference ΔP between the two control chambers 40 and 42 increases, the valve opening force increases, and the push rod 44 and the valve element 49 move downward in FIG. Therefore, the discharge capacity of the compressor 2 decreases.
[0043]
Conversely, when the rotational speed of the engine 11 decreases and the rotational speed of the compressor 2 decreases, the flow rate of the discharged refrigerant discharged from the compressor 2 decreases in conjunction with this. Since the pressure difference ΔP between the first and second control chambers 40 and 42 decreases, the valve opening force decreases, and the push rod 44 and the valve element 49 move upward in FIG. Since the discharge capacity is reduced, the discharge capacity of the compressor 2 increases.
[0044]
At this time, the push rod 44 and the valve element 49 move to a position where the valve closing force and the valve opening force are balanced. This means that the pressure difference ΔP between the first and second control chambers 40 and 42 is equal to the valve closing force ( This means that the discharge capacity of the compressor 2 mechanically changes until a predetermined differential pressure uniquely determined by the electromagnetic attraction force, that is, the target differential pressure ΔPo is reached.
[0045]
Therefore, as described above, the discharge capacity is changed by changing the target differential pressure ΔPo uniquely determined by the valve closing force (electromagnetic attraction force) by controlling the control current In, and the discharge is actually performed from the compressor 2. The flow rate of the discharged refrigerant can be changed.
[0046]
Next, in a vehicle (automobile) equipped with an air conditioner as in the illustrated embodiment, the load of the variable displacement compressor 2 which is a refrigerant compressor of the air conditioner is controlled in accordance with the degree of acceleration of the vehicle. A first embodiment of the control for appropriately balancing the acceleration of the vehicle and the cooling capacity of the air conditioner will be described with reference to FIGS. 3 to 5. In the following description of the embodiment, the load of the compressor will be described as the torque acting on the compressor.
[0047]
FIG. 3 shows a control routine executed by the air-conditioning control device 14 with respect to the compressor load (torque) control. At the start of this control routine, the vehicle engine 11 has been started and the air conditioner (air conditioning) has been started. It is assumed that the switch of (device) is in the ON state.
[0048]
First, in step S101, a determination is made as to whether or not acceleration cut is possible according to the degree of acceleration of the vehicle. The determination of the degree of acceleration is performed using an acceleration determination map as shown in FIG. 4 based on information on the vehicle speed and the throttle opening or the accelerator opening transmitted from the engine control device 19. More specifically, first, in step S101, based on the relationship between the vehicle speed and the throttle opening at the time of acceleration, it is determined whether or not the acceleration at that time is too large to make an acceleration cut, in other words, It is determined whether the acceleration is such that load control of the compressor 2 is required. In the example shown in FIG. 4, the relationship between the throttle opening and the vehicle speed when two types of acceleration are performed by increasing the throttle opening from the state indicated by the point P is shown. When the relationship between the vehicle speed and the throttle opening shifts to the point A after the acceleration, the point A is located in the area X below the acceleration determination line L, so that the acceleration cut can be performed and the load on the compressor can be reduced. It is determined that it does not correspond to the acceleration that requires control. In this case, the compressor load (torque) control according to the acceleration of the vehicle is not performed, and the process proceeds to step S40, and the known control (for example, detected by the blow-out temperature sensor 13) for the compressor 2 according to the temperature state is performed. Control to set the temperature Te to a set temperature. As a result, the portion of the torque generated by the vehicle engine that is absorbed by the compressor 2 does not contribute to the acceleration of the vehicle, so that the acceleration cut is performed and the acceleration is slightly reduced.
[0049]
On the other hand, in the example shown in FIG. 4, since the coordinates of the vehicle speed and the throttle opening at the point B to which the vehicle shifts after acceleration are located in the area Y above the acceleration determination line L, this cannot be acceleration cut. It is determined that the acceleration is an acceleration that requires compressor load (torque) control, and the process proceeds to step S102. In step S102, the necessity of cooling in the vehicle compartment of the current vehicle is determined. Specifically, the cooling capacity (remaining cooling capacity) currently held by the air conditioner, that is, the blowing temperature Te detected by the blowing temperature sensor 13 provided in the downstream flow path of the evaporator 6, is a target value of the blowing temperature. Is determined by adding the allowable temperature width ΔTe to Te0, that is, whether the value is smaller than the required cooling capacity.
[0050]
If the current outlet temperature Te is high and the detected value is larger than the sum of the target outlet temperature Teo and the allowable temperature range ΔTe, it is necessary to give priority to the comfort of the occupant over the acceleration of the vehicle. Since it is determined that there is, the control also proceeds to step S40 in which the normal compressor control is performed. For this reason, when the torque required by the compressor is large, the acceleration cut is performed to that extent and the acceleration of the vehicle is slowed down, but the comfort of the occupant can be ensured even when the cooling heat load is large. .
[0051]
If it is determined in step S102 that the current outlet temperature Te is smaller than the sum of the target value Teo and the allowable temperature range ΔTe, it is determined that the cooling capacity of the air conditioner is sufficient for the time being. In order to give priority to the acceleration of the vehicle, the torque of the variable displacement compressor 2 is temporarily reduced, the torque for the acceleration of the vehicle is increased, and then the torque of the compressor 2 is gradually reduced to the original value. The control of the pattern of returning to the maximum is executed. Therefore, the process proceeds to step S20 for determining a control pattern including the compressor torque reduction amount ΔT and the return time ΔTime.
[0052]
The necessary compressor torque reduction amount ΔT and return time ΔTime are calculated using a compressor torque reduction amount ΔT determination map as shown in FIG. The compressor torque reduction amount ΔT determination map shows (maps) the compressor torque reduction amount ΔT that changes with time. That is, a pattern is adopted in which the torque of the compressor 2 is once reduced by the torque reduction amount ΔT, then gradually increased again, and returned to the original value when the return time ΔTime has elapsed. The torque reduction amount ΔT and the return time ΔTime can be set, for example, such that their magnitudes change according to the degree of acceleration of the vehicle. The vertical axis of FIG. 5 indicates the value of the control current signal In supplied to the displacement control valve 15, which corresponds to the value of the torque of the compressor 2 as apparent from the description of the control valve 15 described above. Therefore, the torque reduction amount ΔT can be controlled by changing the control current signal In.
[0053]
It should be noted that both the acceleration determination map shown in FIG. 4 and the compressor torque reduction amount ΔT determination map shown in FIG. 5 are used from the viewpoint of ensuring both acceleration of the vehicle and cooling of the air conditioner. It is created in advance by an experiment or the like and stored in the air-conditioning control device 14.
[0054]
When the necessary compressor torque reduction amount ΔT and return time ΔTime are determined in step S20 according to the degree of acceleration, step S30 (including steps S31 to S34) for actually performing compressor control according to the torque. Proceed to.
[0055]
In step S30, first, in step S31, the drive torque T of the compressor 2 at present (immediately before acceleration) is calculated (determined). Although the drive torque T of the compressor 2 can be calculated by various methods, in the case of this embodiment, the high-pressure pressure (discharge pressure of the compressor 2) detected by the high-pressure sensor 18 is indirectly compressed. It is calculated based on the value of the control current signal In of the displacement control valve 15 representing the machine discharge displacement and the engine speed.
[0056]
Next, proceeding to step S32, the required compressor torque reduction amount ΔT corresponding to the degree of acceleration calculated in step S20 is subtracted from the drive torque T of the compressor 2 calculated in step S31, and the target compressor torque To is calculated. Is calculated. Then, in the subsequent step S33, a target control current value (target control current signal) Ino for controlling the capacity of the compressor 2 so that the drive torque of the compressor 2 becomes the target compressor torque To is set to the target compressor torque To. , Calculated from the high pressure detected by the high pressure sensor 18 (compressor discharge pressure) and the engine speed.
[0057]
In step S34, the discharge capacity of the compressor 2 is controlled by the target control current Ino calculated in this way, and the compressor 2 is driven by the torque To that is smaller by the necessary compressor torque reduction amount ΔT according to the degree of acceleration of the vehicle. Driven. After that, in order to secure the cooling capacity, the control current In is controlled to gradually return the discharge capacity of the compressor 2 to return to the start state of this routine and prepare for the next acceleration. During this time, the reduced torque in the compressor 2 promotes the acceleration of the vehicle.
[0058]
As described above, when accelerating the vehicle, whether to perform torque control of the compressor 2 of the air conditioner according to the degree of acceleration is determined by giving priority to the cooling capacity, and the comfort of the occupant is maintained. When it is necessary to give priority to acceleration, the necessary compressor torque reduction amount ΔT is calculated, and the compressor capacity is controlled to reduce the compressor 2 by the torque To reduced by the required compressor torque reduction amount ΔT at the start of acceleration. , The load on the engine 11 is reduced, and then the compressor capacity is gradually restored, so that the acceleration performance of the vehicle can be ensured and the cooling capacity suitable for the degree of acceleration of the vehicle can be ensured. .
[0059]
FIG. 6 shows a second embodiment of the control method according to the present invention. The difference from the control method of the first embodiment shown in FIG. 3 is that FIG. 6 does not correspond to step S102 shown in FIG. 3 and, in the determination of step S101, the acceleration at that time is the acceleration shown in FIG. The process proceeds to step S103 when it is determined that torque control of the compressor 2 belongs to the area Y above the acceleration determination line L as indicated by a point B in the determination map and that the torque control of the compressor 2 is necessary.
[0060]
In step S103, apart from the torque reduction amount ΔT calculated by the map of FIG. 5 previously selected according to the degree of acceleration in step S20 and the return time ΔTime, a map as illustrated in FIG. At that time, the torque reduction amount ΔT ′ and the return time ΔTime ′ are calculated from the magnitude of the cooling capacity possessed (remaining) by the air conditioner. In this case, the difference between the actual outlet temperature Te and the target outlet temperature Teo is used as the value indicating the remaining cooling capacity on the horizontal axis of the map in FIG.
[0061]
Then, the process proceeds to the next step S104, where the value calculated in step S20 and the value calculated in step S103 are compared with each other with respect to the torque reduction amount ΔT and the return time ΔTime, and the smaller one (generally, the minimum value) ).
[0062]
After the minimum value of the torque reduction amount ΔT and the minimum value of the return time ΔTime are calculated in this way, the process proceeds to step S30, and the calculated minimum value is used to execute step S31 in the same manner as in the first embodiment. To 34 are executed. By using the minimum values of the torque reduction amount ΔT and the return time ΔTime in this manner, the torque reduction control of the compressor 2 is suppressed as small as possible, the cooling capacity of the air conditioner is increased, and the comfort of the occupants in the passenger compartment is maintained. can do.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram illustrating a vehicle air conditioner to which a control method according to an embodiment of the present invention is applied;
FIG. 2 is a cross-sectional view illustrating a variable displacement compressor used in a vehicle air conditioner.
FIG. 3 is a flowchart showing a first embodiment of the control method of the present invention.
FIG. 4 is an acceleration determination map used in the embodiment.
FIG. 5 is a map for determining a compressor torque reduction amount used in the embodiment.
FIG. 6 is a flowchart illustrating a control method according to a second embodiment of the present invention.
FIG. 7 is a map used in the second embodiment.
[Explanation of symbols]
1. Refrigeration cycle of vehicle air conditioner
2. Variable displacement compressor
6 ... Evaporator
11 Vehicle engine
13 ... Evaporator outlet temperature sensor
14. Air-conditioning control device (A / C ECU)
15. Electromagnetic displacement control valve (discharge displacement control mechanism)
16. Sensor group for automatic control of air conditioner
19 ... Engine control unit (E / G ECU)

Claims (5)

A control method for a vehicle air conditioner including a variable displacement refrigerant compressor having a vehicle engine as a drive source,
Judging the possibility of acceleration cut based on the degree of acceleration of the vehicle;
Comparing the cooling capacity remaining in the air conditioner with the cooling capacity required at that time,
When it is determined that the degree of acceleration of the vehicle is not in the region where acceleration cut is possible and the cooling capacity remaining in the air conditioner exceeds the cooling capacity required at that time, the load of the compressor on the engine is reduced. Controlling the load of the compressor according to a pattern of gradually reducing and then gradually returning;
Otherwise controlling the compressor in accordance with the cooling capacity required at that time. A control method for a vehicle air conditioner including a variable displacement refrigerant compressor having a vehicle engine as a drive source,
Judging the possibility of acceleration cut based on the degree of acceleration of the vehicle;
When it is determined that the degree of acceleration of the vehicle is not in an area where acceleration can be cut, the load on the compressor is controlled according to a pattern in which the load on the engine is temporarily reduced and then gradually restored. Calculating a load reduction amount and a return time of the compressor according to the degree of acceleration of the vehicle,
Calculating a load reduction amount and a return time of the compressor according to the cooling capacity remaining in the air conditioner for controlling the load of the compressor according to the pattern;
Comparing the calculated two load reduction amounts with the two return times to select a minimum value,
Controlling the load on the compressor according to the pattern with the selected load reduction amount and return time;
Otherwise controlling the compressor in accordance with the cooling capacity required at that time. The vehicle air conditioner according to claim 1 or 2, wherein the step of determining whether or not to cut the acceleration based on the degree of acceleration determines the degree of acceleration of the vehicle based on a vehicle speed and an accelerator opening or a vehicle speed and a throttle opening. Control method. The control method for a vehicle air conditioner according to any one of claims 1 to 3, wherein the cooling capacity remaining in the air conditioner is determined based on a blowing temperature of an evaporator. 5. The control method for a vehicle air conditioner according to claim 1, wherein the load on the compressor is determined based on a torque of the compressor.

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