JP2722656B2 - Vehicle air conditioner - Google Patents

Description

The present invention relates to a vehicle air conditioner having a variable displacement compressor.

B. Prior Art In this type of vehicle air conditioner, the temperature of the evaporator is controlled so that the evaporator does not freeze. In general, there is a correlation that the suction pressure Ps of the compressor decreases when the temperature of the air passing through the evaporator decreases.Therefore, the suction pressure Ps does not fall below the set pressure Pr determined according to the freezing start temperature of the evaporator. Is controlled to be constant. That is, when the suction pressure Ps becomes equal to or less than the set pressure Pr, the discharge capacity of the compressor is reduced to reduce the cooling capacity, thereby preventing the evaporator from freezing.

By the way, in this type of vehicle air conditioner, it is necessary to rapidly cool the vehicle interior (hereinafter, referred to as rapid cool) during the daytime in summer, for example, a variable displacement type air conditioner disclosed in Japanese Utility Model Application Laid-Open No. 60-22418. In the compressor control device, the Mac school switch is manually operated to increase the discharge capacity of the compressor.

C. Problems to be Solved by the Invention However, even during rapid cooling, when the suction pressure Ps of the compressor becomes the above-mentioned set pressure Pr, the discharge capacity becomes small, so that the suction pressure Ps does not become lower than the set pressure Pr, that is, The evaporator is controlled not to freeze. For this reason, the cooling capacity during rapid cooling is insufficient, it takes time to cool to a predetermined temperature, and the torque loss during that time is large.

The present invention has been made by discovering that there is a situation where the evaporator does not freeze even when the temperature of the evaporator is below the freezing start temperature, such as during a summer day when rapid cooling is required. The purpose is to improve the cooling capacity at the time.

D. Means for Solving the Problems To be described with reference to FIG. 1 (a), which is a diagram corresponding to the claims, the invention of claim 1 represents a variable displacement type discharge means 101 for pumping a refrigerant and a temperature of an evaporator 102. A detecting means 103 for detecting a physical quantity to be detected, and a capacity changing means 104 for increasing the discharge capacity of the discharging means 101 when the physical quantity detected by the detecting means 103 exceeds a set value, and reducing the discharge capacity when the physical quantity detected becomes smaller than the set value. Output means 105 for instructing rapid cooling, and counting means for counting the number of outputs each time rapid cooling is instructed
107, a setting means 108 for setting the rapid cooling time to a shorter time as the number of times of output of the rapid cooling command is larger, and a first value which is set in accordance with the freezing startable temperature of the evaporator 102 when there is no rapid cooling command. And a set value changing means 106 for setting the set value to a second value corresponding to a temperature lower than the freezing startable temperature for the set quick cooling time when a quick cooling command is issued, To solve the above technical problem.

Further, according to the invention of claim 2, as shown in FIG.
The above-described ejection means 101, detection means 103, and capacity changing means
Determining means 201 for determining whether or not the rapid cooling command is the first command output for the first time after turning on the ignition switch,
And when there is no rapid cooling command, the set value is a first value determined corresponding to the freezing startable temperature of the evaporator,
If this command is determined to be the first command when the rapid cooling command is output, the set value changing means 202 sets the set value to a second value corresponding to a temperature lower than the freezing startable temperature. To solve the above technical problem.

E. Operation When a command for quick cooling is output, the set value becomes a second value corresponding to a temperature lower than the freezing start temperature of the evaporator 102 for a predetermined quick cooling time. For this reason, the compressor is operated just below the freezing limit of the evaporator, and the vehicle interior can be cooled in a shorter time than before under a condition in which the load heat amount is extremely large, such as during the daytime in summer.

In particular, in the first aspect of the present invention, the quick cooling time is shortened as the control is repeated, so that the evaporator 102 does not freeze even if the rapid cooling control is performed a plurality of times.

Further, according to the second aspect of the present invention, the above-described control is permitted only once between the time when the ignition switch is turned on and the time when the ignition switch is turned off.

F. Embodiment -First Embodiment An embodiment of the present invention will be described with reference to FIGS.

(I) Configuration of Embodiment <I-1: Overall Configuration> As shown in FIG. 2, a vehicle air conditioner according to the present invention includes a variable displacement compressor 2, a condenser 3, and an evaporator 4 driven by an engine 1. Unit 100 for a compression refrigeration cycle comprising a liquid tank 5, a liquid tank 5, and an expansion valve 6.
It has. The variable displacement compressor 2 has a suction pressure
When Ps exceeds the set pressure Pr, the inclination angle is increased to increase the discharge capacity, and the set pressure Pr is controlled by a solenoid current _ISOL supplied from the control circuit 40 shown in FIG. Further, the evaporator 4 is disposed in an air conditioning duct 7 having an outside air inlet 7a and an inside air inlet 7b.

Inside and outside air switching doors 8 for controlling the flow rate of air introduced into the air conditioning duct 7 are provided at each of the inlets 7a and 7b. Further, in the air conditioning duct 7, a blower fan 9, a heater unit 10, and an air mixing door 11 are provided as is well known, and the amount of air blown out from a vent outlet 7c and a foot outlet 7d provided in the air conditioning duct 7 is respectively set. A vent door 12 and a foot door 13 to be adjusted are provided. Further, a defroster door 14 is provided at a defroster outlet 7e provided in the air conditioning duct 7.

<I-2: Variable Displacement Compressor> The variable displacement compressor 2 will be described with reference to FIG. This is a so-called swash plate type, in which the suction pressure Ps or the discharge pressure Pd is guided into a casing in which the swash plate is disposed, and thereby the discharge angle is changed by changing the inclination angle of the swash plate. It is disclosed in Japanese Unexamined Patent Publication No. 58-158382.

That is, in FIG.
A rotary shaft 24 that rotates via a pulley 23 by a belt 22 driven by the engine 1 is provided in the rotary shaft 21. A rotary drive plate 25 that rotates integrally with the rotary shaft 24 is pivotally supported on the rotary shaft 24. It is inclined. A non-rotary whipple 26 is mounted on the journal 25a of the rotary drive plate 25, and a piston 28 that slides in a cylinder block 27 is frozen on the non-rotary whipple 26 via a rod 29. Therefore,
When the rotary drive plate 25 rotates, the piston 28
Reciprocates, and sends out the refrigerant sucked from the suction side chamber 30s to the discharge side chamber 30d and sends it to the condenser 3 by pressure. As is well known, a plurality of pistons 28 are arranged at equal intervals on a circumference around the axis of the rotating shaft 24.

Here, the inclination angle of the non-rotary whipple 26 is equal to the suction pressure Ps in the casing 21, that is, in the casing chamber 21R.
Alternatively, the suction pressure Ps is changed by adjusting the pressure difference before and after each piston 28, in other words, by adjusting the pressure difference between the cylinder chamber and the casing chamber, by inducing the discharge pressure Pd, and as shown in FIG. 3 (b). When the discharge pressure Pd is derived as shown in FIG. 3 (c), the inclination angle is reduced. For such tilt angle control, the compressor 2 is configured such that the casing chamber 21R is connected to the suction side chamber 30s or the discharge side chamber.
For the purpose of selectively communicating with 30d, inside the end cover 31,
The control valve 32 is shown in detail in FIG.

<I-3: Control Valve 32> FIG. 4 shows a detailed internal structure of the control valve 32. The control valve 32 has a valve body 322 in which a valve seat member 321 is fitted at the distal end side opening. A valve pin 324 having a ball 323 integrally attached to the distal end is inserted into the valve body 322. Inside the valve body 322, a high-pressure chamber 328 communicating with the discharge side chamber 30d at the port 327, and a port 3
A chamber 330 communicating with the casing chamber 21R is formed through 29A and 329B, and the ball 323 is pressed against the seat 326 by the spring 325 to shut off both.

An end cap 332 having a bellows 331 therein is mounted on the base side of the valve body 322. A spring seat 333 and an end member 334 are attached to both ends of the bellows 331, and a bellows 33 is provided by a spring 335 interposed between the spring seat 333 and the end member 334.
1 is urged in the extension direction.

Further, the end member 3 is inserted through the concave portion of the spring seat 333.
A rod 336 is provided to penetrate through the valve 34, and the tip of the rod 336 comes into contact with a concave portion provided at the base of the valve pin 324.

Between the end cap 332 and the bellows 331, a control chamber communicating with the suction side chamber 30s via ports 337 and 338 formed in the end cap 332 and the end cover 31, respectively.
The control chamber 339 is configured to communicate with the chamber 341 via a passage between a valve body 340 provided at the base of the valve pin 324 and a seat 343 of the valve body 322. This room 341
Is connected to the casing chamber 21R via the port 342.

Further, a movable plate 343 is fixed to the spring seat 333, and the plunger 345 of the electromagnetic actuator 344 is connected to the movable plate 343. A return spring 346 for pressing the movable plate 343 against the spring seat 333 is provided around the electromagnetic actuator 344. The spring force of the return spring 346 is made sufficiently larger than that of the spring 335. The solenoid section of the electromagnetic actuator 344 is connected to an output circuit 49 via a relay 56 as shown in FIG. 5, and is controlled by a solenoid current _{ISOL as} described later.

Generally, when the suction pressure Ps of the compressor 2 exceeds a preset pressure Pr (hereinafter, set pressure), the control valve 32 operates. That is, the bellows 331 contracts against the spring force of the spring 335, the rod 336 is displaced downward, and the spring force of the spring 325 causes the valve pin 324 to follow its descending operation (at this time, the movable plate 343 is immovable. is there). Thus, the ball 323 is seated on the seat 326, and the valve body 340 is separated from the seat 343. FIG. 3 (b) schematically shows this state. As can be seen from this figure, the suction pressure Ps is supplied from the control chamber 339 to the chamber 341 and the port 3
It is guided to the casing chamber 21R via 42, the inclination angle increases, and the discharge capacity increases.

If the suction pressure Ps is lower than the set pressure Pr, the spring
The rod 336 pushes the valve pin 324 upward by the spring force of 335, the valve body 340 is seated on the seat 343, and the ball
323 is separated from the sheet 326 (at this time, the movable plate 343 is immovable.) FIG. 3C schematically shows this state.
It is. As can be seen from this figure, the high pressure chamber 328 and the chamber 330
And the discharge pressure Pd through the port 329B and the casing chamber 21R
And the inclination angle is reduced, and the discharge capacity is reduced.

Here, the set pressure Pr is changed and controlled as follows.

When the solenoid portion of the electromagnetic actuator 344 is demagnetized, the movable plate 343 is at a position where the springs 335 and 346 are balanced, and the movable plate 343 moves upward in proportion to the increase in the solenoid current, and The spring force of the solenoid 335 increases in proportion to the solenoid current. As a result, the set pressure Pr of the control valve 32 also increases in proportion to the solenoid current.

<I-4: Control Circuit 40> FIG. 5 shows an example of the control circuit 40 of the vehicle air conditioner according to the present invention. The external temperature T is input to the CPU 41 via the input circuit 42.
Outside air temperature sensor 43 for detecting _AMB , indoor temperature sensor 44 for detecting vehicle interior temperature T _INC , solar radiation sensor 4 for detecting solar radiation Q _SUN
5, the evaporator 4 downstream of the air temperature (hereinafter, the suction temperature of) the coolant temperature sensor 47 suction temperature sensor 46 for detecting the T _INT, provided on the outlet side pipe surface of the expansion valve 6 for detecting the refrigerant temperature Tref, engine cooling A water temperature sensor 48 for detecting the water temperature Tw is connected, and various kinds of temperature information and heat amount information are input to the CPU 41 from these sensors 43 to 48. Also, input circuit 4
2, air conditioner switch 57, blower fan switch 5
8, ignition switch 59, defroster switch 60,
An intake pressure sensor 61 for detecting the intake pressure of the intake manifold, a rotational speed sensor 62 for detecting the rotational speed of the engine,
An air mix door opening sensor 63 that detects the opening of the air mix door 11 is also connected.

Further, the CPU 41 has an intake actuator 50, an air mixed door actuator 51,
The vent door actuator 52, the foot door actuator 53, the defroster door actuator 54, and the blower fan control circuit 55 are connected, and the blower fan motor 9 is connected to the blower fan control circuit 55. Output circuit 49
In addition, the control valve 32
The solenoid of the electromagnetic actuator 344 attached to is connected.

The CPU 41 has sensors 43 to 48, 61 to 63, and switches 57 to 60.
Based on various information input from the controller, various actuators such as the intake actuator 50, the air mixing door actuator 51, etc. are drive-controlled to appropriately set the air inlet, outlet and outlet temperature or the set pressure Pr of the control valve 32. Control. Further, the blower fan motor 9 is drive-controlled by the blower fan control circuit 55 by the air flow control signal to appropriately control the blower fan air flow.

(II) Operation of Embodiment Next, the operation of the embodiment will be described.

<II-1: Basic Flowchart-> FIG. 6 is a flowchart showing the basic control of the air conditioning control device executed by the CPU 41.

In step S10, initial settings are made. In the normal auto air conditioner mode, for example, the set temperature _TPTC is initially set to 25 ° C. In step S20, various information from each sensor is input.

The data information of each of these sensors will be specifically described. The set temperature T _PTC is obtained from a control panel (not shown), the vehicle interior temperature T _INC is obtained from the indoor temperature sensor 44, and the outside air temperature is obtained.
T _AMB is provided from the outside air temperature sensor 43, suction temperature T _INT is provided from the suction temperature sensor 46, and refrigerant temperature T _ref is provided from the refrigerant temperature sensor 47. Further, the engine water temperature Tw is determined by the water temperature sensor 48.
Therefore, the solar radiation amount Q _SUN is given from the solar radiation sensor 45.

Next, in step S30, the outside air temperature _TAMB obtained from the outside air temperature sensor 43 is processed to a value _TAM corresponding to the actual outside air temperature, excluding the influence from other heat sources. Then step S
At 40, the solar radiation amount information as the amount of light from the solar radiation sensor 45 is processed into a value Q ' _SUN as a heat amount suitable for subsequent conversion.
In step S50, the set temperature T _PTC set on the control panel is processed to a value T ′ _PTC corrected according to the outside air temperature. In step S60, a target outlet temperature To is calculated from T ′ _PTC , T _INC , T _AM , and Q ′ _SUN, and the target outlet temperature To is calculated.
And the air mix door 11 according to the deviation from the actual outlet temperature
Is calculated. In step S70, the compressor 2 is controlled as described below. In step S80, each outlet is controlled. In step S90, selection switching of the suction port, that is, the outside air introduction port 7a and the inside air introduction port 7b is controlled. In step S100, the air flow from the outlet is controlled by controlling the blower fan 9.

<II-2: Compressor control> FIG. 7A shows the compressor control (step
It is a flowchart explaining (S70) in detail.

In FIG. 7A, in step S701, it is determined whether or not the blower fan 9 is operating (is turned on) based on a signal from the blower fan switch 58. If not, the compressor 2 is stopped in step S702 ( Off). If it is operating, in step S703, the detected refrigerant temperature
Based on Tref, state 1 or state 2 is read and the state is stored in a predetermined storage area. Note that Tr in step S703
ef ₁ is the refrigerant temperature when the heat load is small, and Tref ₂ is
The refrigerant temperature is somewhat higher than Tref ₁ . Next, if it is determined in step S704 that the state is 2, the compressor is stopped in step S702. When it is determined that the state is 1,
In step S705, the determined state of the engine rotational speed by a signal from the speed sensor 62, until engine speed as shown in the case of the low speed region (Figure 7 (b) is raised to a predetermined rotational speed Rref ₂ During this period, the process proceeds to step S706, and in the high rotation region (until the rotation speed decreases to the predetermined rotation speed Rref ₁ as shown in FIG.
Proceed to 712 destroke control. The high and low rotation regions are determined as shown in FIG. 7B according to the number of rotations. In step 706, based on the outside air temperature T _AM which is correction processing, to determine the one of the states 3 to 5 and stored in a predetermined storage area, the process proceeds to step S707. Step S706
In, T _AM1 and T _AM2 says the outside air temperature is extremely low state, T _AM3 and T _AM4 refers to the outside air temperature is relatively high state.

In step S707, it is determined whether or not the defroster switch 60 is on, and if it is off, in step S708,
It is determined whether or not the target outlet temperature To calculated in step S60 is equal to or lower than a temperature Trcd at which the air mixing door 11 blocks all the air flowing into the heater unit 10. If Trcd or less, the process proceeds to step S709 to perform rapid cool-down control.

<II-3: Rapid Cool-Down Control> FIG. 8A shows a flowchart of the rapid cool-down control in step S709 of FIG. 7A. In step S7081, a count value C indicating the number of times of rapid cool down is determined, and if C = 0, step S7082 is performed.
Proceed to. In step S7082, time perform rapid cool-down control (rapid cooling time) Step by setting t ₁ to t _MAX
Proceed to S7091. If C = 1 is determined in step S7081, the time t ₁ is set to t _MAX / 2 in step S7083, and if C ≧ 2 is determined in step S7081, step S7084
To set the time t ₁ to t _MAX / 4 and proceed to step S7091. In step S7091, the target temperature of the outlet side of the air passing through the evaporator (hereinafter goal suction temperature) with a T _'INT and the temperature T ₁ of the freezing start possible temperature below the evaporator above a clocking time Time1 timer setting the t _1.

Here, the reason the temperatures T ₁ according to the target suction temperature T _'INT, if the ambient temperature as in summer day is high, further than the actual air temperature T _INT freezing start possible temperature of the evaporator downstream even if lower temperatures T ₁ is due to the present inventor has confirmed that not freeze if within a predetermined time,
Further, by setting the target suction temperature _T'INT to be low as described above, the set pressure Pr of the control valve 32 for adjusting the discharge capacity of the compressor 2 can be lowered.
This is because the discharge capacity of the compressor 2 can be kept large in the region of the lower suction pressure Ps, and the cooling capacity can be sufficiently exhibited.

Next, in step S7092, the solenoid energizing current I
Calculate _SOL1 .

As shown in the flowchart of FIG. 9, this calculation is performed by first calculating the difference (T T between the suction temperature T _INT and the target suction temperature T ′ _INT
INT -T _'INT) is calculated (steps S 941), determined in step S942 in accordance with FIGS. 10 and 11 respectively proportional current Ip and integral term current I _I from this difference. Here, the proportional term current I _p is calculated based on the difference calculated in step S941.
From the figure, the integral term current I _I is calculated from FIG. 10 based on the same difference, and ΔI _I is obtained as a value I _I (= I _I + ΔI _I ) obtained by adding ΔI _I to the previous I _I. Desired. In step S943, it obtains the current corresponding to the difference between the proportional term current I _P and the integral-term electric-current I _I as a solenoid energization current I _SOL1. That is, the solenoid energizing current I _SOL1 is obtained by I _SOL1 = I _P −I _I (1).

However, I _P amps, _I I is milliamps.

In Step S7093 of FIG. 8 (a), the suction temperature T _INT is determined whether freezing start possible temperature T ₄ or less,
Perform the iteration step S7092 and step S7093 until the affirmative, at a T _INT = T _4, the process proceeds to step S7095 and starts counting the timer Time1 in step S7094. In step S7095, similar to step S7092 to calculate the solenoid energization current I _SOL1. Then, in step S7096, it determines the target air temperature To is whether the temperature T ₅ or more. Here, the temperature T ₅ is an air mixing door 11 is at a temperature such as to start the flow of air to the heater unit 10.
Step S7096 is affirmative the process proceeds to step S7098, and determines whether or not the timer Time1 has completed the counting of t ₁ in If a negative step S7097. If step S7097 is denied, the process returns to step S7095. If an affirmative and willing increased evaporator target suction temperature T 'one by one degree / sec _INT in step S7098, then in step S7099, and then returns incremented count value C described above by one. Here, the count value C is cleared to zero when the ignition switch 59 is turned off.

According to the above, FIG. 10, as can be seen from FIG. 11 and Expression 1, at the time of rapid cool-down, I _SOL1 is suction temperature T _INT of the evaporator 4 decreases rapidly to a temperature T _1. When the solenoid current I _SOL1 decreases, the movable plate 343 of the electromagnetic actuator 344 shown in FIG. 4 is displaced downward, and the set pressure Pr for opening the valve body 340 decreases. As a result, even if the compressor suction pressure Ps is a small value, the valve body 340 opens and the suction pressure Ps is guided to the casing chamber 21R, and the inclination angle is increased, that is, the compressor discharge capacity is increased (cooling capacity is increased).

Such control is, as shown in the characteristic diagram of FIG. 8 (b), the suction temperature T _INT is reduced to a temperature T ₄ t ₁ minute or until the target air temperature T ₀ is the temperature T ₅ or more, Continued. That is, it is possible to only compressor 2 inlet temperature T _INT predetermined time remain set to a temperature T ₁ is being executed overstroke operation is rapid cool-down control, is cooled rapidly cabin, such as during the summer day.

Such rapid cool-down control can be performed a plurality of times. The set time t ₁ is t _MAX minutes for the first time, t _MAX / 2 minutes for the second time, and t _MAX / 4 for the third time and thereafter. Minutes. That is, as the number of times increases, the time of the rapid cool-down becomes shorter, thereby obtaining the following effects. That is, the rapid cool-down control does not freeze the evaporator within a certain period of time,
When performing the this control multiple consecutive times, there is a possibility that the time t ₁ is frozen is the evaporator 4 at a constant.
The freezing can be prevented in accordance with the number of times increases therefore by shortening the time t _1.

On the other hand, in step S708 of FIG.
When To is not lower than the temperature Trcd, in step S710, it is determined whether or not the vehicle is in an acceleration state based on the intake pressure of the intake manifold detected by the intake pressure sensor 61. _INT is
_Judge whether it is less than T _INT1 degree. If affirmative, step S
At 712, destroke control is executed.

<II-4: Destroke Control> FIG. 12 (a) shows a flowchart of the destroke control. In step S7121, it is determined whether or not T _INT > T ′ _INT +1. If not, the process proceeds to step S7122,
If affirmative, the process proceeds to step S7123. In step S7122, the target air temperature T _'INT is increased by ₁₀ ° T, the supply in the next step S7124, the solenoid of the electromagnetic actuator 344 based on the first equation from the graph of FIG. 10 and FIG. 11 described above The current value I _SOL1 is controlled. On the other hand, in step S7123, the target air temperature T _'INT the T ₁₁ degrees (>
As T _10), for controlling the electromagnetic actuator 344 by the current value I _SOL1 obtained from the first equation in the same manner in step S7124.

That determines, in step S7121, the relative comparison between the target inlet temperature T _'INT and the suction temperature T _INT, the cooling state of the current evaporator. Be denied means that it is operated close to a certain extent evaporator target value, in step S7122, the current value by increasing the target suction temperature T _'INT only T ₁₀ ° is relatively small numerical I _SOL1 To determine. As a result, the movable plate 343 in FIG. 4 moves upward and the spring force of the spring 335 increases,
The set pressure Pr of the control valve 32 is set higher,
Even when the suction pressure Ps of the compressor 2 is higher than before, the compressor discharge pressure Pd is guided into the casing chamber 21R, and the inclination angle is kept small. In this case, when the target suction temperature _T'INT increases, the actually detected suction temperature _TINT increases, the deviation from the target blowout temperature To changes, and the air mix door 11 is driven to the closing side. Even if it decreases, the blowing temperature does not rise.

The opening of the air mix door 11 is controlled as shown in FIG. 12 (b).

In FIG. 12 (b), constants A to G are initialized in step S601, and in step S602, the current air mix door opening X is input based on the signal of the air mix door opening sensor 63. Next, in step S603, a deviation S between the target outlet temperature To and the actual outlet temperature is determined based on the illustrated equation. Then, in step S604, the deviation S is set to a predetermined value So.
Compare. If S <−So, the air mix door opening is set to the cold side, that is, the heater unit in step S605.
Closed so that the air flow through 10 is small. In the case of S> -So, the opening of the air mixing door is set to the hot side, that is, the opening side so that the air flow rate passing through the heater unit 10 is increased. In the case of | S | ≦ + So, the current opening degree is maintained as it is.

On the other hand, the fact that step S7121 of the destroke control is denied means that the air temperature sucked through the evaporator
T _INT While cooling capacity of is the evaporator ₁₀ degrees or less T is considerably exhibited means that the target inlet temperature T _'INT yet there is gap, the cooling performance is to focus on acceleration performance while ignoring some extent Therefore, to increase the solenoid energization current I _SOL1 by the evaporator target suction temperature T _'INT to T ₁₁ degrees. Here, the predetermined temperature T ₁₁ is determined experimentally at a temperature corresponding to the evaporator downstream air temperature of the discharge capacity without stopping the compressor while minimizing. Therefore, the movable plate 343 moves further upward than in the case of step S7122, and the set pressure of the control valve 32 is
Pr is set higher than in the above case, and even if the suction pressure Ps of the compressor 2 becomes considerably high, the casing chamber 21
The compressor discharge pressure Pd is guided into R, and the inclination angle is kept small.

The above steps S7121 to S7123 are also executed when it is determined in step S705 in FIG. 7A that the engine speed is high.

As described above, the destroke control is executed at the time of acceleration or during operation in the high engine speed range, and each destroke control has the following operational effects.

De-stroke control during acceleration This de-stroke control is executed during acceleration and when the evaporator suction temperature T _INT is equal to or lower than T _INT1 degree.
When the evaporator suction temperature T _INT is equal to or lower than T _INT1 degree, the cooling capacity of the evaporator is considerably exhibited, and the acceleration performance is improved at the expense of some cooling performance. That is, when the destroke condition is determined, the set pressure Pr of the control valve 32 is increased and the compressor 2
Even if the suction pressure Ps of the casing becomes relatively large, the casing chamber 21R
The compressor discharge pressure Pd is derived to reduce the discharge capacity of the compressor. As a result, the absorption horsepower of the compressor is reduced and the acceleration performance is improved.

In this case, if the current cooling is almost sufficient, specifically, if the suction temperature T _INT has almost reached the target suction temperature T ′ _INT , the set pressure Pr of the control valve 32 is set slightly higher, Improve acceleration performance while maintaining cooling performance to some extent. On the other hand, the suction temperature T _INT is _equal to the target suction temperature T ′ _INT
If there is still a gap, the set pressure Pr of the control valve 32 is set higher, and the acceleration performance is more important than the former, ignoring the cooling performance.

De-Stroke Control in High Speed Range When the engine speed is in the high speed range, the variable displacement compressor also rotates at high speed, adversely affecting its durability.
Further, if the rotation speed is high, the required refrigerant flow rate can be obtained even if the inclination of the compressor is small. For this reason, in the high-speed rotation region, the inclination angle of the variable displacement compressor is reduced to reduce the reciprocating speed of the piston, thereby improving durability.

If step S711 in FIG. 7A is denied,
In step S713, it is determined whether the air conditioner switch 57 is on. If on, jump to step S716,
If it is off, it is determined at step S714 which of the above-mentioned states 3 to 5 respectively. If state 3, step S715
In step S702, control goes to step S702 to turn off the compressor 2.

<II-5: Fuel Saving and Power Saving Control> FIG. 13 (a) shows a flowchart of fuel saving and power saving control. In step S7151, it is determined whether or not the outlet is in a high level (B / L) mode. If the mode is the B / L mode, the process proceeds to step S7152; if the mode is not the B / L mode, the process proceeds to step S7153.
Proceed to. In step S7152 and S7153, according to the graph of FIG. 13 (b), obtaining the target suction temperature T _'INT from the target air temperature To. That is, in the B / L mode, the target suction temperature _T'INT is set according to the characteristic diagram II, and in the modes other than the B / L mode, the target blow temperature _T'INT is set according to the characteristic diagram I.

Then, the process proceeds to step S7154, determination intake temperature T _INT is, by one to whether the temperature range defined by the temperature T ₆ is freezing start possible temperature T ₄ and a temperature slightly lower than, or state 6 or 7 I do. In step S7155, it is determined whether or not the state is 7. If the determination is affirmative, that is, if the state is 7, the compressor is turned off in step S7157 and the process returns to the predetermined processing. On the other hand, if it is determined that the state is 6, in step S7156, the solenoid current value I _SOL1 is controlled in the same manner as described above, and the process returns to the predetermined processing.

According to the above procedure, the compressor is extremely finely controlled so that the suction temperature _TINT is in accordance with the target blowout temperature To, and fuel saving and power saving are achieved for the following reasons.

As before, the current suction temperature T _INT and the target outlet temperature To
When the desired opening temperature is obtained by adjusting the opening degree of the air mixing door 11 due to the deviation from the above, the suction temperature _TINT may be undesirably too low depending on the operating condition. And the blowing temperature is controlled to the target value. For this reason, the compressor wastefully uses power and adversely affects fuel economy.

According to this embodiment, for a certain target outlet temperature To,
In order to obtain the temperature, the air temperature downstream of the evaporator 4, that is, how much the suction temperature _TINT should be determined is determined as an experimental value, and a target calculated according to the graph of FIG. From the outlet temperature To, the target suction temperature T '
_INT is determined, and the discharge capacity of the compressor is controlled based on the target suction temperature T ′ _INT so that the suction temperature T _INT does not decrease excessively. This means that the compressor is operated with the minimum required displacement (inclination angle), and therefore the absorption horsepower is reduced, contributing to power saving and fuel saving.

By the way, as in this embodiment, operating the compressor with the minimum necessary capacity means that the suction temperature T _INT is extremely close to the target suction temperature To, and the larger the deviation between the two, the larger the opening degree. Controlled air mix door 11
Is almost completely closed. Therefore, the outlet is B / L
When the mode is set, for example, the temperature of the air blown out from the underfoot outlet 7d and the temperature of the air blown out from the vent outlet 7c become substantially equal, and the effect of so-called cold head heat cannot be obtained. Therefore, in the B / L mode, the power saving and fuel saving effects in the above sense are slightly reduced.
By setting _TINT to a low value, the air mix door 11 tends to be opened, and for example, the temperature of the air blown out from the underfoot outlet 7d is increased, thereby obtaining the effect of head cold foot heat.

That is, for the same target air temperature the To, B / L mode target inlet temperature T in the _'INT is the target inlet temperature T in other modes' is set lower than _INT, the B / L mode and the other modes In comparison, the solenoid current I _SOL1 according to the first equation is smaller, the suction temperature T _INT for the same target outlet temperature To is smaller, and as described above, the air mix door 11 is set to the open side, and the effect of head-feeling foot heat is obtained. Is obtained.

In FIG. 7A, when step S707 is affirmative, that is, when the defroster switch 60 is on, the states 3 to 5 stored in step S706 are determined in step S716, and according to the result, Various controls are performed.

That is, in the case of state 3, in step S717, MA
X Dehumidification control is performed.

<II-6: MAX Dehumidification Control> FIG. 14 shows a flowchart of the MAX dehumidification control. In step S7171, it sets the target suction temperature T _'INT freezing start possible temperature T ₄ ° as described above. Next, step S717
2 Oite, based on the suction temperature T _INT, determines state 6 or 7. If the state 7 is determined in step S7173, the compressor 2 is turned off in step S7174. If it is determined that the state is 6, in step S7175, the solenoid current I _SOL1 of the electromagnetic actuator 344 is controlled based on the above-mentioned first formula, FIGS. 10 and 11, as shown in FIG.

On the other hand, if the state 4 is determined in step S716 in FIG. 7A, low-temperature mist control is performed in step S718.

<II-7: Low-Temperature Demist Control> FIG. 15A is a flowchart of low-temperature demist control. In this control, the current I _SOL2 of the solenoid actuator 344, I _P obtained from the graph of FIG. 17 and FIG. 18 on the basis of the refrigerant temperature Tref and the target refrigerant temperature T'ref
And ΔI _I are calculated based on the first equation.

That is, in step S7181, the outside air temperature T _AM + T ₈ is set as the target refrigerant temperature T′ref ₂ and the target refrigerant temperature T′r
The outside air temperature T _AM −T ₉ is set as ef ₃ . Also,
₂ minutes t the timer Time2, respectively set t ₃ minutes timer Time3. Next, in step S7182, it is determined whether or not the flag 1 is 0. If the determination is affirmative, the flag 2 is set to 0 in step S7183.
It is determined whether or not. If a positive determination is made, step S7184
In starts counting the Time2, in step S7185, first select the target refrigerant temperature T'ref ₃ as T'ref, in step S7186, the solenoid current I _SOL2 first
Determined according to the procedure shown in Figure 16. This is the same as FIG. 9 except that, as shown in the graphs of FIGS. 17 and 18, the proportional term current I _P and the integral term current I _I are obtained from the deviation between the refrigerant temperature Tref and the target refrigerant temperature T′ref. The procedure is the same as that of the solenoid current I _SOL1 , and the description is omitted.

Next, in step S7187, it is determined whether or not the time measurement of Time2 has been completed. Before the completion of the timing, the determination is negative and the process proceeds to step S1794, where 1 is set to the flag 1 and the process returns to the predetermined procedure. On the other hand, when the time measurement of Time2 is completed, in step S7188, the flag 1 is set to 0, and in step S71
Start time measurement of Time3 at 89. Then, in step S7190, the flow advances to step S7191 to select the target refrigerant temperature T'ref ₂ as T'ref, controls the solenoid current I _SOL2 in a similar manner as described above. Further, in step S7192, Time
It is determined whether or not the time measurement of 3 is completed. If the time measurement is not completed, the process proceeds to step S7195 to set 1 to the flag 2 and returns to the predetermined procedure. Upon completion of the clocking, the flag 2 is set to 0 in step S7193, and the process returns to the predetermined procedure.

According to the above procedure, over time, and the target refrigerant temperature T'ref ₃ and T'ref ₂ is selected and I _SOL2 is adjusted as Fig. 15 (b). As a result, dehumidification and the refrigerant temperature 4 ° lower than the outside air temperature is performed when adjusting the I _SOL2 in T'ref _3. Incidentally, to pulsating driving the compressor by selecting alternately and T'ref ₃ and T'ref ₂ is to prevent the seizure of the compressor to improve the oil lubrication during operation the flow rate of the refrigerant is small.

In the configuration of the above embodiment, the variable capacity compressor is the discharge means 101, the suction temperature sensor 46 is the detection means 103,
The structure for guiding the control valve 32, the suction pressure Ps, and the discharge pressure Pd to the casing chamber 21R is a capacity changing means 104,
The CPU 41, in particular, each step in FIGS. 8 and 9 and the like use the set value changing means 106, and the CPU 41, especially step S708 in FIG. 7 (a).
Outputs the output means 105 to the CPU 41, in particular, the steps in FIG. 8 (a).
S7099 constitutes the counting means 107, and the CPU 41, in particular, steps S7081 to S7084 of FIG. The suction pressure Ps of the compressor 2 is a physical quantity, and the set pressure Pr corresponding to the suction pressure Ps is a set value. The first value is the suction temperature downstream of the evaporator.
I _INT is the set pressure Pr set to the suction pressure value corresponding to T ₄ degrees, and the second value is the set pressure set to the lower suction pressure value corresponding to T ₁ degrees. Pr. This set pressure Pr is controlled by controlling the solenoid energizing current _ISOL to the control valve 32.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG.

FIG. 19 is a diagram corresponding to FIG. 8 (a), showing the rapid cool-down control. FIG. 8 (a)
Steps similar to those described above are denoted by the same reference numerals.

First, in step S2001, it is determined whether or not a flag F described later is set, that is, whether or not F = 1. If step S2001 is denied, the process proceeds to step S7091 described above,
If affirmative, the process proceeds to step S702 in FIG. 6A, the compressor 2 is turned off, and the process returns.

After the process in step S7098, the flag F is set, that is, the process returns with F = 1. Here, the flag F is released (F = 0) by turning off the ignition switch 59. Other processes are the same as in the first embodiment, and a description thereof will be omitted.

In the above procedure, the affirmation of step S2002 indicates that the process of FIG. 8A is performed only after the ignition switch 59 is turned on, and in this case, the steps S7091 to S7098 are rapidly performed. Cool down processing is performed. On the other hand, if step S2002 is denied, that is, after the ignition switch 59 is turned on,
In the case where the process has shifted to the process of FIG. 8A for the second time, the compressor is stopped without performing the rapid cool-down process. That is, the rapid cool-down process can be performed only once between turning on and off the ignition switch 59, and freezing of the evaporator 4 caused by performing the rapid cool-down control a plurality of times is prevented.

(III) Modification The discharge capacity of the compressor is controlled by the inclination angle of the swash plate, but may be of an oblique axis type. In addition, although the suction pressure or the discharge pressure is guided into the casing chamber to control the inclination angle, other methods may be used. Further, when it is determined that there is a rapid cooling request when the target outlet temperature To is equal to or less than Trcd degrees, it is determined whether or not there is a rapid cooling request by a signal for controlling the vehicle interior temperature, the outside air temperature, or the opening of the air mix door. Is also good. Furthermore, a rapid cooling request switch may be provided, and the above-described control may be performed when the switch is turned on by the operation of the operator and the rapid cooling request is output.

In addition, when the suction pressure exceeds the set value, the discharge capacity is increased, and when the suction pressure is equal to or less than the set value, the discharge capacity is reduced to prevent freezing of the evaporator.However, other physical quantities representing the temperature of the evaporator, for example, the refrigerant temperature, etc. The discharge capacity may be controlled in comparison with a set value.

Furthermore, the rapid cool control is performed at the target suction temperature T ′ _INT
Is set to T ₁ degree and t ₁ minute or the target outlet temperature To is T ₅ (>
T ₁ ) is performed until the temperature becomes equal to or higher, but these values are variously changed according to the freezing limit of the air conditioner.

G. Effects of the Invention According to the present invention, when it is necessary to rapidly cool the cabin temperature, such as during a summer day, the evaporator is allowed to be set lower than its freezing startable temperature for a predetermined time. Meanwhile, the discharge capacity of the compressor during that time is increased, and the cooling performance is temporarily improved, thereby enabling rapid cooling. According to the invention of the first aspect, the predetermined time is shortened every time the control in which the evaporator is set to be lower than the freezing startable temperature is repeated, so that such control is performed a plurality of times. Even the freezing of the evaporator can be prevented. Further, according to the second aspect of the present invention, the above-described control is permitted only once between the time when the ignition switch is turned on and the time when the ignition switch is turned off.

[Brief description of the drawings]

1 (a) and 1 (b) are claims correspondence diagrams. FIGS. 2 to 18 illustrate a first embodiment of a vehicle air conditioner according to the present invention. FIG.
3 (a) is a diagram showing the internal structure of the variable displacement compressor, FIGS. 3 (b) and 3 (c) are diagrams illustrating the operation thereof, FIG. 4 is a detailed internal structure diagram of the control valve, and FIG. FIG. 6 is a basic flowchart, FIG. 7 (a) is a flowchart of compressor control, FIG. 7 (b) is a diagram showing a rotation speed region, and FIG. 8 (a) is a diagram of rapid cool down control. flowchart, Figure 8 (b) is a characteristic diagram showing the time variation of the suction temperature I _INT at that time, the flow chart for FIG. 9 controls the solenoid current I _SOL1, FIGS. 10 and 11 are solenoid current I A graph for calculating _SOL1 , FIG. 12 (a) is a flowchart of destroke control, FIG. 12 (b) is a flowchart of air mix door opening control, and FIG. 13 (a) is fuel saving and power saving control. Flowchart, FIG. 13 b) is a graph for selecting the two characteristics at that time, FIG. 14 is a flowchart of the MAX dehumidification control, FIG. 15 (a) is a flowchart of the low temperature demist control, and FIG. Characteristic diagram showing the time change of the target refrigerant temperature Tref ₂ and Tref ₃ ,
FIG. 16 is a flowchart for controlling the solenoid current I _SOL2 , and FIGS. 17 and 18 are graphs for calculating the solenoid current I _SOL2 during the low-temperature demist control. FIG. 19 is a flowchart of the rapid cool-down control according to the second embodiment of the present invention. 1: Engine, 2: Compressor 4: Evaporator, 9: Blower fan 10: Heater unit 32: Control valve 40: Control circuit, 101: Discharge means 102: Evaporator, 103: Detection means 104: Capacity change means, 105: Output means 106: setting value changing means, 107: counting means 108: setting means, 201: determining means 202: setting value changing means

Claims (2)

(57) [Claims] A discharge means of a variable displacement type for pumping a refrigerant; a detection means for detecting a physical quantity representing a temperature of an evaporator; and a discharge of the discharge means when the physical quantity detected by the detection means exceeds a set value. A capacity changing means for increasing the capacity and reducing the discharge capacity when the capacity becomes equal to or less than the set value; an output means for instructing rapid cooling; and a counting means for counting the number of outputs each time the rapid cooling is commanded. Setting means for setting the quick cooling time to a shorter time as the number of times of output of the quick cooling command is greater; and a first value which is determined in accordance with a freezing startable temperature of the evaporator when the quick cooling command is not present. When there is the rapid cooling command, the set value is changed to a second value corresponding to a temperature lower than the freezing startable temperature for the set rapid cooling time. Air conditioning system characterized by comprising a stage. 2. A variable displacement type discharge means for pumping refrigerant, a detection means for detecting a physical quantity representing the temperature of the evaporator, and a discharge means for discharging the discharge means when the physical quantity detected by the detection means exceeds a set value. A capacity changing means for increasing the capacity and decreasing the discharge capacity when the set value becomes equal to or less than the set value; an output means for instructing rapid cooling; and a first command which is output for the first time after the ignition switch is turned on. When there is no rapid cooling command, the set value is set to a first value determined corresponding to a freezing startable temperature of the evaporator, and when the rapid cooling command is output. If the command is determined to be the first command, setting value changing means for setting the setting value to a second value corresponding to a temperature lower than the freezing startable temperature; Air conditioning system characterized by comprising.