JP2834735B2 - Control method of air conditioner for axle - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method of a vehicle air-conditioning control device for controlling a refrigerant suction pressure in a variable displacement compressor. [Prior Art] Conventionally, as shown in FIG. 14, a cooling cycle of a vehicle air conditioner control system includes a compressor 1, a condenser 81, a liquid tank 83, an evaporator 80 and the like. In recent years, capacity control type compressors have become widespread. According to this, the capacity can be linearly controlled in accordance with the heat load 82, and the compressor can sufficiently cope with the heat load 82 to provide a cooling feeling. And the ON / O of compressor 1 that occurred during cycling control
Shock based on FF is not applied to the engine, and driving performance can be improved. This kind of capacity control type compressor 1
As an example, there is known a compressor in which the compressor 1 is formed of a swash plate type, the capacity is automatically adjusted by changing the inclination angle θ of the swash plate, and controlling the refrigerant suction pressure Ps of the compressor 1. In this case, an electromagnetic actuator is attached to the compressor 1 described above.
A suction pressure control mechanism D including a heat load detecting means S;
This output is electrically controlled externally to make correction. [Problems to be Solved by the Invention] Since the conventional control method of the vehicle air conditioner is configured as described above, only the suction pressure control mechanism D is controlled by the output of the thermal load detecting means S. It is. Therefore, if the conventional vehicle accelerates or runs uphill and the engine load increases, the engine load on the compressor must be reduced so that acceleration and uphill can be performed smoothly.
The conventional one cannot satisfy such a demand satisfactorily.
Although it is known to reduce the compressor capacity or cut off during acceleration or climbing a slope, it has been difficult to strictly respond to both reducing the load on the engine and satisfying the air conditioning performance. The present invention has been made to solve the above problems, when the engine load is high, the suction pressure of the compressor commensurate therewith by obtaining the distribution value T ₂ of the driving torque to the compressor against engine load By controlling the air conditioner, the engine load on the compressor can be reduced without impairing the air-conditioning performance. As a whole, both the sufficient air-conditioning performance is ensured and the engine load on the compressor is reduced. It is an object of the present invention to obtain a control method of a vehicle air conditioner that can strictly respond to the above demand. [Means for Solving the Problems] The control method for a vehicle air conditioner according to the present invention provides a heat load-corresponding suction pressure value setting characteristic (P _S1 ) indicating a relationship between a heat load and a suction pressure set value (P _S1 ). X), a suction pressure set value (P _S1 ) corresponding to a change in heat load is obtained, and a compressor drive torque expected value indicating a relationship between the suction pressure set value and the compressor drive torque for each difference in heat load. The expected value (T ₁ ) of the compressor drive torque corresponding to the suction pressure set value (P _S1 ) is obtained with reference to the set characteristic (V), while the distribution value (T ₂ ) of the engine load and the compressor drive torque is obtained. With reference to an engine load corresponding compressor drive torque distribution value setting characteristic (W) showing the relationship with (W), a compressor drive torque distribution value (T ₂ ) corresponding to a change in engine load is obtained, and the above distribution value (T ₂ ) T ₂₎ and Comparing the size of the serial forecast (T _1), the distribution value (T ₂₎ is the expected value (T ₁₎ when greater than, the suction pressure set point (P
The _S1) was set in the suction pressure control means (49), also when the distribution value (T ₂₎ is less than the expected value (T ₁₎ is
The distribution values suction pressure set value corresponding to (T ₂₎ to (P _S2) and determined by reference to the characteristic (V) for setting the suction pressure setpoint (P _S2) to the suction pressure control means (49) Thus, the suction pressure control mechanism (D) is controlled based on the suction pressure set values (P _S1 , P _S2 ) set in the suction pressure control means (49). [Operation] The control method of the vehicle air conditioner according to the present invention includes:
Expected value (T ₁ ) and distribution value (T ₂ ) of compressor drive torque
By comparing the two values, it is determined whether the drive torque can be sufficiently distributed to the compressor (whether the engine load is large) or not. At times, the engine load on the compressor should not be imposed. That is, the fact that the distribution value (T ₂ ) is larger than the expected value (T ₁ ) means that the engine load is small and there is sufficient margin in the compressor drive torque that is acceptable (ie, can be allocated) to the engine load. Therefore, in this case, the compressor can be operated with sufficient capacity based on the suction pressure set value (P _S1 ) obtained from the heat load corresponding suction pressure value setting characteristic (X). At this time, priority is given to air conditioning, and sufficient air conditioning is performed. If the distribution value (T ₂ ) is smaller than the expected value (T ₁ ), it means that the engine load is large and there is no room for the allowable compressor drive torque for the engine load. The distribution load (T ₂ ) corresponding to the engine load determined by the corresponding compressor drive torque distribution value setting characteristic (W) prevents the load on the compressor from being applied to the engine. At this time, priority is given to reduction of the engine load on the compressor, and uphill running, acceleration, and the like become smooth. That is, a distribution value (T ₂ ) and an expected value (T ₁ ) as a judgment value are obtained, and these values are compared. Based on the comparison result, control for giving priority to air conditioning based on the suction pressure set value (P _S1 ) is performed. Is performed, or the control for giving priority to reducing the engine load on the compressor is performed based on the suction pressure set value (P _S2 ), and one of the suction pressure set values controls the suction pressure control mechanism (D). It is set in the suction pressure control means (49). Accordingly, sufficient air conditioning is performed except when the engine is under a high load such as uphill or acceleration, and the engine load on the compressor is reduced when the engine is under a high load such as uphill or acceleration. Therefore, as a whole, the control method can strictly meet both the demands of ensuring sufficient air-conditioning performance and reducing the engine load on the compressor. An embodiment of the present invention will be described below with reference to FIGS. 1 to 13. Note that the same components as those in FIG. 14 are denoted by the same reference numerals and description thereof is omitted. FIG. 1 is a block diagram showing an embodiment of a control method of a vehicle air conditioner according to the present invention. In FIG. 1, reference numeral 41 denotes a signal from an accelerator depression amount sensor 31 or a tilt sensor 32 to process an engine load. calculation for the engine load computing means, distribution value calculating means for calculating a distribution value T ₂ of the drive torque to a more compressor 1 output (engine load) and characteristic W of Figure 4 of the engine load calculating means 41 42, 47 Means for calculating the expected value of compressor driving torque 46
By the expected value T ₁ of the driving torque obtained is compared with the distribution value T ₂ of the said drive torque, the determination result suction pressure setpoint and comparison means for outputting the correction calculation unit 48 for calculating the mixing door opening , 43 are an inside air sensor 33, an outside air / solar radiation sensor 34,
A heat load calculating means 44 for calculating a heat load based on the output from the mixed door opening sensor 35 is a target for calculating a target value of the temperature of the air to be blown out of the air outlet based on the output of the heat load calculating means 43. The blow-out temperature calculating means 45 is a calculating means for calculating the compressor suction pressure set value Ps and the opening θ of the mix door based on the output of the target blow-out temperature calculating means 44. The compressor drive torque expected value calculation means 46 calculates the compressor suction pressure set value _PS1 and the fifth
As shown in the figure, the expected value T _{1 of the} compressor drive torque is calculated based on the characteristic V obtained in advance according to the magnitude of the heat load.
Is calculated. The correction calculating means 48 calculates the compressor suction pressure set value P calculated by the calculating means 45 in accordance with the determination result of the comparing means 47.
_S1, or to control the intake pressure control means 49 and the mix door control means 40 to mix door opening theta _1, performs the following processing. That is, the characteristic V is obtained from the distribution value T ₂ of the heat load and the driving torque.
Calculates the suction pressure setpoint P _S2 based on, and the correction opening theta ₂ of the mixing door when the suction pressure setpoint P _S2 is calculated, the suction pressure P _S2, the suction pressure control in the mixing door opening angle theta ₂ Means 49 and the mixed door control means 40 are controlled. 1 is a compressor, and 12 is an actuator controlled by the mix door control means 40 to drive the mix door. Here, characteristic W whereas the engine load, in which pre-determined whether distribution value T ₂ of the driving torque to the compressor is how. That is, the engine load is a load when the vehicle is running and increases when climbing a hill or accelerating, or changes based on the operation of auxiliary equipment such as a dynamo and a compressor. Considering the case, the former case has a larger engine load than the latter, and therefore the torque (distribution value T ₂ ) that can be distributed to the compressor is smaller. Therefore, distribution value T ₂ of the driving torque to the compressor 1 as indicated by the characteristic W is made smaller as the engine load increases. The characteristic W is obtained in advance by various experiments according to the engine type, and if the suction pressure P _S2 corresponding to the above-mentioned distribution value T ₂ is set, the torque is distributed to the compressor in accordance with the engine load to load the engine. Air conditioning can be performed without any problems. In addition, as a method of detecting the engine load,
As shown in FIG. 6, a characteristic F representing the magnitude of the engine load with respect to the magnitude of the accelerator depression detected by the accelerator depression sensor is obtained for each speed or acceleration of the driving train, and a table is prepared. A method of reading the load, or a method of obtaining a characteristic E representing the magnitude of the engine load with respect to the amount of accelerator depression as shown in FIG. 7 for each engine speed and making a table, and reading the engine load from this table Alternatively, as shown in FIG. 8, a characteristic G representing the magnitude of the engine load with respect to the magnitude of the accelerator opening detected by the accelerator opening sensor in the carburetor is obtained for each negative pressure of the manifold and tabulated. And the method of reading the engine load from this, or as shown in FIGS. 9 (a) and 9 (b), Mercury in a glass tube 17 which is positioned horizontally
18 to form a tilt sensor 19, and the tilt sensor 19
The conductor 14 short-circuited by the mercury 18 may be embedded in the resistor 15 to detect the resistance value from both ends 15a of the resistor 15. That is, when the slope of the uphill is large as shown in FIG. 9 (b) and when the slope is small as shown in FIG. 9 (a), the former has a smaller number of conductors 14 to be short-circuited than the latter,
Therefore, the resistance between both ends 15a of the resistor 15 increases. The control method of the vehicle air conditioner having the above configuration will be described below with reference to the flowchart of FIG. First, in step S1, when a heat load signal is input from each of the sensors 33, 34, and 35 to the heat load calculation means 43, the heat load is calculated in step S2, and in step S3, the target outlet temperature calculation means
The target outlet temperature is calculated by 44, the suction pressure set value P _S1 and the mixed door opening θ ₁ are calculated by the calculation means 45 based on the characteristic X by the calculation means 45 in step S4, and the suction pressure set value P _S1 and the mixed door open degree theta _1, and the expected value T ₁ of the driving torque of the compressor based on the characteristic V is calculated. In step S6, the engine load calculating means 41 fetches signals from the sensors 31 and 32, and calculates the engine load in step S7. In step S8, the distribution value T ₂ of the driving torque to the compressor 1 from the engine load and the characteristic W is calculated. Is calculated. Step S ₉ In the predicted value T ₁ of the driving torque by comparing the magnitudes of the allocation values T ₂ of the drive torque, T ₁ ≦ when T _2, i.e. predicted value T ₁ of the driving torque of the compressor for example a small engine load When the drive torque distribution value T ₂ is larger,
Since the compressor can be operated with sufficient capacity,
At 10, the calculation means 45 sets the suction pressure control means 49 and the mix door control means 40 so that the suction pressure set value P _S1 and the mix door opening θ ₁ become the same. Accordingly, these are controlled in accordance with the magnitude of the heat load, and air conditioning is sufficiently performed. However, when T ₁ ≦ T ₂ is not satisfied, that is, when the engine load is large such as when climbing a hill, steps 11 and 12
In suction pressure set point P _S2 by the correction calculating unit 48, the mix door opening theta ₂ is calculated, the suction pressure control unit 49 and so that the suction pressure setpoint P _S2, the mixing door opening angle theta ₂ in step 13 Since the mixed door opening control means 40 is set, the torque is distributed to the compressor in accordance with the engine load, so that uphill running, acceleration, and the like can be smoothly performed. The plurality of characteristics (V) in FIG. 5 are characteristic curves determined for each value of the heat load. Step S5
Then, since the compressor suction pressure set value (P _S1 ) and the heat load are already known from FIG. 3, the value of the compressor suction pressure set value Ps (horizontal axis) and the heat load are known in FIG. Thus, the driving torque of the compressor is required. Based on the compressor suction pressure set value (P _S1 ) obtained in FIG. 3, the drive torque of the compressor obtained in FIG. 5 is set as an expected value (T ₁ ). Also,
In step S8, in FIG. 4, the torque distribution value (T ₂ ) for the engine load (that is, the allowable compressor driving torque for the engine load) is uniquely determined. If the determination in step S9 is YES, the load can be permitted (that is, can be distributed) with respect to the engine load.
If it is determined that the compressor drive torque has sufficient margin, the compressor suction pressure is controlled by the compressor suction pressure set value (P _S1 ) obtained in FIG. Is to be done. If the determination in step S9 is NO, it is determined that the engine load is large, and based on the distribution value (T ₂ ) corresponding to the engine load obtained in FIG.
From the value of the driving torque (T) (vertical axis) (that is, the distribution value (T ₂ )) of the compressor in the figure and the heat load, a compressor suction pressure set value (P _S2 ) corresponding to the engine load is obtained.
By controlling the compressor suction pressure with the compressor suction pressure set value (P _S2 ), the load on the engine to the compressor is reduced, so that uphill running, acceleration, and the like can be performed smoothly. Next, an example of the variable displacement compressor 1 including the suction pressure control mechanism D will be described with reference to FIGS. In the figure, reference numeral 1 denotes a compressor. The compressor 1 has a cylindrical case 2, a cylinder head 4 airtightly mounted on an end face of the case 2 via a valve plate 3, and an airtight mount on the other end face. And the head member 5. A suction pressure control mechanism D including a pressure adjustment valve 6 is disposed inside the cylinder head 4, and a suction chamber 7 and a discharge chamber 8 are formed around the pressure adjustment valve 6. The suction chamber 7 is connected to an outlet of an evaporator 80 of a refrigerant cycle of the air conditioner, and the discharge chamber 8 is connected to an inlet of a condenser 81 of the refrigerant cycle. Inside the case 2, a piston mechanism 20 for compressing the refrigerant is provided. The piston mechanism 20 includes a cylinder block 21 and a piston 22, and a plurality of piston mechanisms are arranged in a circumferential direction with an axis parallel to the center axis. The piston 22 is slidably fitted in each cylinder 23 in the direction of arrow K. The piston 22 is provided with a piston rod 24, and the piston rod 24 is provided with a ball joint 24a at the tip. A discharge valve 10 is provided at the opening end of the discharge port 9 of the discharge chamber 8, and a suction valve (not shown) is also provided at the suction port 11 of the suction chamber 7. Thus, the piston mechanism 20 sucks the low-pressure refrigerant in the suction chamber 7 into the cylinder 23 through the suction port 11 and the suction valve, compresses the low-pressure refrigerant by the piston 22, and compresses the high-temperature and high-pressure refrigerant in the discharge port 9 and the discharge valve 10. Through the discharge chamber 8. Next, in order to drive the piston mechanism, the drive mechanism 50
Are provided in the crank chamber 26. This drive mechanism 50
A drive shaft 25 rotatably disposed along a substantially central axis of the compressor 1, an arm member 52 fitted to the other end of the drive shaft 25, and a drive shaft 25 disposed on an outer periphery of the drive shaft 25. And a swing plate 55 provided on the outer periphery of the slider. The other end of the drive shaft 25 extends outwardly through the head member 5, and the extended end portion 25b has an output shaft side pulley of a vehicle-mounted engine and a drive belt (not shown). (Not shown) is mounted. On the other hand, the slider 54 has a substantially cylindrical shape, is slidable on the drive shaft 25 in the axial direction (the direction of arrow K), and is configured to rotate together with the drive shaft 25. It is pressed toward the cylinder block 21 by the fitted internal slider 54a and the coil spring 13. The oscillating plate 55 has a disc shape, a center hole is loosely fitted to the slider 54, and is rotatably connected to the slider 54 via a trunnion pin 59. Therefore, the swing plate 55
Is biased by the coil spring 13 to the side where the inclination angle θ decreases. At a predetermined position on the end surface of the rocking plate 55 on the side of the arm member 52, a parallel guide portion 55a projects in the radial direction as shown in FIG. A coil spring 16 is stretched between them, and the end face of the rocking plate 55 is brought into contact with the cam surface 52c at the tip of the arm member 52 by the spring 16. In this manner, the swing plate 55 rotates in the direction of arrow H around the cam surface 52c as the rotation center, and the angle θ with respect to the vertical surface changes within a predetermined range. Further, a ball joint 24a of the piston rod 24 of each piston 22 is connected to one end surface of the swing plate 55 so as to be slidable in the circumferential direction. Thus, when the position where the cam surface 52c of the oscillating plate 55 comes into contact with a certain cylinder 23 approaches the cylinder 23 due to the rotation of the oscillating plate 55, the piston 22 slides toward the cylinder head 4 to compress and discharge the refrigerant. The piston 22 slides toward the head member 5 side 5 to suck the refrigerant. The swinging plate 55 has an inclination angle with respect to a vertical plane according to the difference between the pressure Pc of the refrigerant leaked into the crank chamber 26 and the urging force of the coil spring 13 and the pressure Pd (reaction force of the piston 22) in the cylinder 23. θ changes, and the stroke of the piston 22 increases or decreases due to the change in the inclination angle.
That is, the discharge and suction amount of the refrigerant is increased or decreased. A pressure adjusting valve 6 is provided in the cylinder head 4 to adjust the pressure in the crank chamber 26 to control the inclination angle θ of the swing plate 55. This pressure regulating valve 6 opens and closes a communication port 21c between the case 61, the suction chamber 7 (low-pressure refrigerant side) and the crank chamber 26 as shown in FIGS. 12 and 13, and receives pressure in the suction chamber 7. Face 6
2a, and external signals from the heat load 82 (the inside air sensor 33, the outside air / solar radiation sensor 34, the mixed door opening sensor 3
5), the solenoid 63 is excited by a current value supplied from the suction pressure control means 49 via the cable 77, whereby the movable iron core 64 is Energizing coil spring 65
An electromagnetic actuator 68 that operates to approach the fixed iron core 66 to transmit and controls the opening degree of the valve body 62 via the transmission rod 67, and is located between the valve body 62 and the movable iron core 64, The fixed iron core 66 and the support plate 69 are slidably fitted to each other to transmit the mutual displacement between the valve body 62 and the movable iron core 64 and to move the movable iron core 64.
Rod 67 having a function of setting the positional relationship (gap Z) between the shaft and the fixed iron core, and covering the support plate 69 and the transmission rod 67, and integrally with the valve body 62 by brazing (or soldering) or the like. And bellows 78 to be assembled. Further, since the mounting seat 74 of the coil spring 65 is screwed to the screw shaft 75, the spring force can be changed when the setting position of the mounting seat 74 is changed. Thus, the opening of the valve body 62 is determined by the spring force (coil spring 65, bellows 78) and the pressure Ps in the suction chamber 7 when no current is supplied to the solenoid 63, that is, when the electromagnetic actuator 68 is off (normally open). The valve pressure is high and the pressure is open.) However, the discharge pressure Pm of the evaporator 80 changes due to the heat load 82 and the pressure loss between the evaporator 80 and the compressor 1 causes the evaporation pressure of the refrigerant to change substantially. Cooling capacity cannot be obtained. Then, current is supplied to the solenoid 63 from the suction pressure control means 49. That is, when the electromagnetic actuator 68 is turned on, it is determined by the attraction force and the spring force change of the fixed iron core 66 and the pressure Ps in the suction chamber 7, which change depending on the current value supplied to the solenoid 63, and the electromagnetic actuator 63 is corrected. Pressure Pc inside
Is adjusted, the tilt angle θ of the swing plate 55 is determined, and the discharge and suction amount of the refrigerant is adjusted. For example, when the heat load 82 decreases, the discharge pressure Pm of the evaporator 80 decreases. As a result, the suction pressure control means 49
The current supplied to the solenoid 63 from the
Since the suction force of the valve 66 is increased and the opening of the valve body 62 is reduced, the pressure Pc in the crank chamber 26 is increased, the inclination angle θ of the swing plate 55 is reduced, and the discharge suction capacity of the compressor 1 is reduced. . Therefore, the discharge pressure Pm of the evaporator 80 increases because the suction amount of the compressor 1 has decreased, and the refrigerant flow rate has also decreased since the discharge amount has decreased, so that the pressure loss between the compressor 1 and the evaporator 80 has also decreased, and the evaporator 80 has a reduced pressure loss.
Pressure Pm is kept constant. On the other hand, when the heat load increases, the discharge and suction amount of the compressor 1 increases due to the reverse operation, and the pressure Pm is kept constant. As described above, under the same setting conditions, the suction pressure control means 49 corrects the pressure regulating valve 6 so that the evaporation pressure becomes constant irrespective of the change in the heat load, so that a desired cooling state can be maintained. Or more in the present invention, so as to control the intake pressure of the compressor commensurate therewith by obtaining the distribution value T ₂ of the compressor driving torque to the engine load,
The engine load on the compressor can be reduced without impairing the air-conditioning performance, and as a whole, strictly responding to the demands of both ensuring sufficient air-conditioning performance and reducing the engine load on the compressor. To obtain a control method of a vehicle air conditioner capable of performing the following. [Effects] As described above, according to the control method of the present invention, the distribution value (T ₂ ) as the judgment value and the expected value (T ₁ ) are obtained, and these values are compared. And whether to perform control for giving priority to air conditioning based on the suction pressure set value (P _S1 ) or to give priority to reducing the engine load on the compressor based on the suction pressure set value (P _S2 ). The suction pressure control is performed based on the suction pressure set value of
In addition, the engine load on the compressor can be reduced, and as a whole, control can be performed that can strictly respond to both the demands of ensuring sufficient air-conditioning performance and reducing the engine load on the compressor.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are a block diagram and a flowchart of a control method of a vehicle air conditioner according to an embodiment of the present invention;
3 to 9 are characteristic diagrams and sensors for each calculation means, FIGS. 10 to 13 are sectional plan views and sectional side views of a variable displacement compressor, and sectional side views of a suction pressure control mechanism. FIG. 14 is a sectional view showing a configuration of a conventional vehicle air conditioner. 1… Compressor, 12… Actuator, 31,32,33,3
4, 35 sensors, 41, 42, 43, 44, 45, 46, 47, 48 calculation means, 47 comparison means, 40 49 control means.

Claims (1)

(57) [Claims] A method for controlling a vehicle air conditioner comprising: a variable displacement compressor having a refrigerant suction pressure control mechanism (D); and a suction pressure control means (49) for controlling the suction pressure control mechanism (D). determined pressure set value (P _S1) heat load corresponding suction pressure value setting characteristic showing the relationship between (X) with reference to the corresponding suction pressure set value to the variation of the thermal load (P _S1), the difference of the thermal load Estimated compressor drive torque corresponding to the suction pressure set value (P _S1 ) with reference to the compressor drive torque expected value set characteristic (V) showing the relationship between the suction pressure set value and the compressor drive torque for each compressor (T ₁₎ while obtaining the engine load by referring to the distribution values (T ₂₎ engine load showing the relationship between the corresponding compressor driving torque distribution value setting characteristics of the driving torque of the engine load and the compressor (W) Distribution value of the driving torque of the compressor corresponding to the variation (T ₂₎ the determined and compares the magnitude of the distribution value (T ₂₎ the expected value (T _1), the distribution value (T ₂₎ Is larger than the predicted value (T ₁ ), the suction pressure set value (P _S1 ) is set in the suction pressure control means (49), and the distribution value (T ₂ ) is set to the predicted value (T ₁ ). ₁ ) If less than the above allocation value (T ₂ )
The suction pressure set value (P _S2 ) corresponding to the suction pressure is determined by referring to the characteristic (V), and the suction pressure set value (P _S2 ) is set in the suction pressure control means (49), whereby the suction pressure set value (P _S2 ) is obtained. The suction pressure set value (P _S1 , P _S
A control method for a vehicle air conditioner, wherein the suction pressure control mechanism (D) is controlled based on _S2 ).