JP2984955B2 - Vehicle air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner having a rapid cool-down function for maximizing the capacity of a variable capacity compressor for a predetermined period of time at the time of vehicle driving and a function for preventing freezing of an evaporator. About.

[0002]

2. Description of the Related Art Conventionally, rapid cool-down control of a vehicle air conditioner is disclosed in Japanese Patent Application Laid-Open No. 1-111517, in which means for setting a target temperature of an evaporator and means for detecting the actual temperature of the evaporator. By setting the target temperature of the evaporator below the freezing temperature of the evaporator (for example, −10 ° C.), the compressor capacity usually determined by the difference between the target temperature of the evaporator and the actual temperature is maximized. The rapid cool-down control is continued for a predetermined time (for example, 10 minutes) after the actual evaporator temperature becomes equal to or lower than a predetermined value (for example, 3 ° C.).

Further, in order to prevent the freezing, Japanese Patent Application Laid-Open No. 1-2282015 discloses that an evaporator temperature is detected, and when the detected value is less than a predetermined value and continues for a predetermined time, the electromagnetic clutch is turned off. An apparatus for stopping the operation of the cooling cycle to prevent the evaporator from freezing is disclosed.

[0004]

However, when the vehicle is restarted immediately after the vehicle is stopped or after a short stop, the temperature of the evaporator is not sufficiently increased, and dew condensation occurs on the surface of the evaporator. If rapid cool-down control is executed in this state, there is a problem that the evaporator freezes easily, and furthermore, the operation of the cooling cycle was stopped to prevent freezing. In such a case, there is a problem that the air conditioning level is reduced.

[0005] Therefore, the present invention determines the state of the evaporator when the vehicle is started, when the vehicle is restarted after a short stop, and when the evaporator is in a state where the evaporator is easily frozen by this determination. It is an object of the present invention to provide an air conditioner for a vehicle in which the time of rapid cool down control is shortened to prevent the evaporator from freezing.

[0006]

The present invention will be described with reference to FIG. 1. In a vehicle air conditioner having at least an evaporator for cooling introduced air in an air conditioning duct, when the heat load is larger than a predetermined value. A rapid cool-down start determining means 100 for requesting a shift to the rapid cool-down control; an engine cooling water temperature detecting means 110 for detecting a cooling water temperature of the engine 14; and an engine detected by the engine cooling water temperature detecting means 110. 1
4. A restart determining means 120 after a short stop, which determines whether the engine 14 is restarting after a short stop based on the cooling water temperature of No. 4, and a restart determining means 120 after the short stop.
According to the above, when it is determined that the restart is not a restart after a short stop, the quick cool down control is executed for a predetermined time, and when it is determined that the restart is a restart after a short stop, it is not the restart. And a rapid cool-down control means for executing the rapid cool-down control by shortening the operation time as compared with the predetermined time.

[0007]

Therefore, according to the present invention, when the vehicle is started, the rapid cooling down control requested by the rapid cooling down start determining means 100 is performed by the engine cooling water temperature detected by the engine cooling water temperature detecting means 110. If the engine cooling water temperature is higher than a predetermined value, it is determined that the restart is not a restart after a short stop. The evaporator is determined to be a start and can be executed for a shorter time than a predetermined time when the restart is not a restart after a short stop, so that the evaporator is in a state where the evaporator is easily frozen. Freezing can be avoided.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

The vehicle air conditioner shown in FIG.
On the most upstream side of the air-conditioning duct 1, an inside / outside air switching door (INTAKE door) 5 driven by an inside air inlet 3, an outside air inlet 4, and an actuator 6 and appropriately selecting the inside air inlet 3 or the outside air inlet 4 is provided. The air introduction unit 2 is provided.
A blower 7 is provided on the downstream side of.

Downstream of the blower 7 is provided a temperature control means comprising an evaporator 8, an air mix door 16 driven by an actuator 17, and a heater core 9, and further downstream of the air conditioning duct 1. Diff outlet 18, vent outlet 19, and foot outlet 2
0 is provided and is selectively opened by mode doors 22a, 22b, and 22c driven by the actuator 23.

The evaporator 8 includes a variable capacity mechanism 24.
A variable capacity compressor 10, a condenser 11,
The piping is connected in series with the receiver tank 12 and the expansion valve 13 to form a cooling cycle. In this cooling cycle, the high-temperature and high-pressure gas refrigerant compressed by the variable displacement compressor 10 driven by being connected to the driving engine 14 by the electromagnetic clutch 15 is condensed by radiating heat to the air passing through the condenser 11 in the condenser 11. After being subjected to gas-liquid separation and dehydration by the receiver tank 12, the refrigerant is adiabatically expanded by the expansion valve 13 to become a mist-like refrigerant. This mist-like refrigerant absorbs heat of the air passing through the evaporator 8 in the evaporator 8 and evaporates to become a gaseous refrigerant. By repeating the heat absorbing action of the evaporator 8 and the heat dissipating action of the condenser 11, the air passing through the evaporator 8 is cooled, and the cooling level changes according to the amount of refrigerant discharged from the variable capacity compressor 10. .

The variable displacement compressor 10 is, for example, a wobble plate type. As shown in FIG. 3, a drive shaft 51 connected to a traveling engine 14 via an electromagnetic clutch 15 is inserted into a compressor body 10a. A wobble plate 52 is attached to this drive shaft 51 by a hinge ball 53.
Are coupled through. This wobble plate 52
A piston 55 connected to the wobble plate 52 is supported by a crank chamber 54 formed in the compressor body 10a so as to be swingable with respect to the drive shaft 51 with a hinge ball 53 as a fulcrum. The cylinder is reciprocated in the cylinder bore 56.

A pressure control valve 57 is provided in the variable displacement compressor 10 so as to face the crank chamber 54. The pressure control valve 57 includes a valve body 59 that regulates communication between the crank chamber 54 and a suction chamber 58 that communicates with the suction side, a pressure response member 60 that moves the valve body 59 according to the pressure in the suction chamber 58, A solenoid 6 that moves the valve body 59 in accordance with the amount of current I _SOL (capacity variable signal) to the electromagnetic coil 59
The piston 55 and the cylinder bore 5 are controlled by externally controlling the amount of current I _SOL to the electromagnetic coil 61.
The amount by which the blow-by gas leaking into the crank chamber 54 from the position 6 returns to the suction side is adjusted.

A variable displacement mechanism 24 for changing the displacement of the variable displacement compressor 10 is constituted by the pressure control valve 57 and the like. In the variable capacity mechanism 24, the electromagnetic coil 6
When the amount of current I _SOL flowing through the solenoid valve 1 increases and the magnetic force of the solenoid 62 increases, the crank chamber 57 and the suction chamber 5
The force acts in a direction to narrow the communication with the suction chamber 8 and the amount of blow-by gas leaking from the crank chamber 54 to the suction chamber 58 is reduced.
For this reason, the pressure of the crank chamber 57 increases, the stroke of the piston 55 decreases, and the discharge amount of the refrigerant decreases.

By controlling the amount of power I _SOL from outside, the amount of refrigerant is controlled and the cooling capacity of the evaporator can be controlled.

Further, the heater core 9 of the vehicle air conditioner is provided.
Is supplied with cooling water for the traveling engine, thereby heating the air passing therethrough.

In the vehicle air conditioner having the above configuration, the inside air or outside air selected by the inside / outside air switching door 5 is blown to the downstream side of the air conditioning duct 1 by the blower 7. This air is cooled by passing through the evaporator 8 and is divided into air passing through the heater core 9 and air bypassing the heater core 9 depending on the opening degree of the air mixing door 16. The air heated by passing through the heater core 9 and the bypassed cooled air are mixed downstream of the heater core 9 to obtain air adjusted to a desired temperature. The temperature-controlled air is blown into the vehicle interior 21 from the outlets 18, 19, and 20 selected by the mode doors 22a, 22b, and 22c, and controls the temperature of the vehicle interior 21.

In order to control the vehicle air conditioner,
A microcomputer 41 is provided, and a temperature sensor 44 for detecting at least an outside air temperature, a temperature sensor 43 for detecting a temperature in a vehicle interior, a solar radiation sensor 45 for detecting an amount of solar radiation,
And a signal from a temperature sensor 46 attached to the evaporator 8 (or a temperature sensor attached near the downstream side of the evaporator 8 for estimating the evaporator temperature) 46
In the present invention, the signal from the temperature sensor 49 for detecting the temperature of the engine cooling water is supplied to a multiplexer (MP).
X) A signal is input through the 47 and the A / D converter 48, and further a signal from the operation panel 25 described below is input to the microcomputer 41.

The microcomputer 41 includes a central processing unit (CPU) (not shown) and a read-only memory (R).
OM), a random access memory (RAM), an input / output port (I / O), and the like, which processes the above-mentioned input signal in accordance with a predetermined program, and outputs each of the output circuits 40a to 37f. The control unit controls, for example, the actuators 6, 17, and 23, the blower 7, the electromagnetic clutch 15, and the capacity variable mechanism 24.

The operation panel 25 includes an AUTO switch 31 for automatically controlling the air conditioner, an A / C switch 35 for turning on / off the operation of the cooling cycle, a DEF switch 34 for forcibly setting the blowing mode to the differential mode, and an air conditioner. Switch 32 for stopping the operation of the vehicle, REC switch 33 for manually setting the mode of the intake air to inside air circulation (REC) or outside air introduction (FRE), up / down switches 28a and 28b for setting the temperature in the passenger compartment, and a display unit. 28c, a mode switch 26a for manually setting a blowing mode, and a display unit 26.
b, a FAN switch 27a for manually setting the air flow rate of the blower 7 and the display unit 2
7b. The display panel 30 having the display units 28c, 27b, 26b is controlled by the microcomputer 41 via the display circuit 29.

Hereinafter, a flowchart of an air conditioning control program executed by the microcomputer 41 will be described with reference to the flowchart.

The flowchart shown in FIG.
This is a main program executed in the microcomputer 41 in the automatic control mode of the air conditioner. This main program is started from step 200 when the AUTO switch 31 is pressed. In step 300, the set temperature T _SET and the vehicle interior temperature T
_INC , outside air temperature T _OUT , solar radiation T _SUN , evaporator temperature T _E , and engine coolant temperature T _W are input as data.

[0023] From these data, the target air temperature X _M is a heat load signal is calculated by a formula 1 below in step 400.

[0024]

X _M = A ・ T _SET -B ・ T _OUT -C ・ T _E -D ・ T _SUN -E ・ T _INC + F

A, B, C, D and E are gain constants, and F is a correction term. These values are set to values at which the optimum air-conditioning effect is increased by experiments.

[0026] The target air temperature X _M computed in step 400, step 500, outside air switching door position, for example in FIGS. 5 (a) as indicated by the internal air circulation mode (REC) and the outside air introduction mode (FRE) In step 600, the blower voltage of the blower 6 is changed as shown in FIG.
This is set as shown in FIG. FIG.
(B) MAX HI indicates the maximum high-speed operation of the blower 7, HI indicates high-speed operation, and LOW indicates low-speed operation.

Further, in step 700, the target air temperature X _M, 5 to control the air mixing door 16 as shown in (c) is performed, it is performed compressor control that follows in step 800, further steps At 900, the mode doors 22a, 22b, 22c
Is performed as shown in FIG. 5D, and the above control is repeated thereafter.

In FIG. 5C, FC (full cool) indicates a state where the air mix door 16 is fully closed or close to the upstream side of the heater core 9, and FH (full hot) indicates a state where the air mix door 16 is fully open or closed. It shows a state close to that. Further, VENT (vent mode) in FIG. 5D shows a so-called upper blowing mode, which blows out only from the vent outlet 19, and HEAT (heat mode) shows a so-called lower blowing mode, which blows out only from the foot outlet 20. ,
BI / L (bi-level mode) is an air outlet switching signal T _F
(T _F = Te + K ₁ Θ; K ₁ is a calculation constant, Θ is the opening of the air mix door 16), and shows a mode in which FH is changed linearly from FC.

The compressor control in the step 800, an evaporator target outlet temperature T _'INT computed from target air temperature X _M by the normal view 5 (e), the actual evaporator air outlet temperature is calculated from the evaporator temperature T _E The compressor capacity is adjusted so that the temperature difference ΔT from T _INT is 1 or less. For example, ΔT is calculated by proportionally integrating (PI) to obtain the compressor capacity signal I _SOL . The compressor capacity increases as the temperature difference ΔT increases.

The rapid cool-down control according to the present invention, which is a part of the compressor capacity control, is shown in the flowchart of FIG.

In step 852, the target blowing temperature X
It is determined whether or not _M is −10 or less. If _M is −10 or more, the process proceeds to step 865 to determine whether or not rapid cool down control (hereinafter, cool down control) is being performed ( The flag of the cool-down control is determined).
If it is determined in step 865 that the cool-down control is being performed (the cool-down control flag is 1),
Proceeding to step 859, if the cool-down control is not being performed (the cool-down control flag is 0), the process proceeds to step 866.
From the cool down control, and returns to the normal compressor control routine.

[0032] In step 852, the target air temperature X _M is, in the case of -10 or less, perform a cool-down control (cool down control flag 1) in step 853, the process proceeds to step 854.

At step 854, it is determined whether or not the engine cooling water T _W is equal to or higher than 55 ° C. In this determination, if the engine cooling water temperature is 55 ° C. or higher, it can be determined that the start of the vehicle is a start after a short stop. Therefore, the process proceeds to step 856. It is determined that the start is not the stop after the stop, and Step 855 is executed.
Then, the timer is set to a first predetermined time (for example, 10 minutes).

[0034] At step 856, the difference between the vehicle interior temperature T _INC and the evaporator temperature T _E is, it is determined whether or not 10 ° C. or higher. In this determination, when the temperature difference is 10 ° C. or more, since the temperature of the evaporator is not sufficiently increased, the stop time of the vehicle is short, and it can be determined that the evaporator is in a wet state and the possibility of freezing is large. At step 858, the timer is set to a second predetermined time (for example, 2 minutes) shorter than the predetermined time,
When the temperature is 10 ° C. or lower, the evaporator temperature is higher than that when the temperature is 10 ° C. or higher. Therefore, it can be determined that the risk of freezing is reduced more than in the above state. A third predetermined time (e.g., 5 minutes) which is intermediate between the first predetermined time and the second predetermined time is set.

[0035] After the setting of the timer in step 855,857,858, proceeds to step 859, 'sets _INT -10, thereby forcing evaporator target outlet temperature T' evaporator target air temperature T and _INT The cool-down control that maximizes the compressor capacity can be performed by increasing the temperature difference ΔT from the actual evaporator outlet temperature T _INT .

[0036] Thereafter, in step 860, a determination target air temperature X _M is whether 8 or more. In this determination, if the value is 8 or more, it means that the thermal condition has decreased. Therefore, in step 863, the cool-down control is ended (the cool-down control flag is set to 0), and in step 864, the cool-down transition control is performed. This is executed (the cool-down transition control flag is set to 1), and the process exits from step 866 to another compressor control.

[0037] In step 860, if the target air temperature X _M is 8 or less, in order to request the cool-down control is continued in step 861, the actual evaporator outlet air temperature T _INT is at 3 ° C. or less, In step 855, 857, or 858, it is determined whether the timer has elapsed the set time t.

In this determination, the continuation of the cool-down control is determined. During the continuation, the above-described compressor capacity control is performed in step 862, and after the time is up, the process proceeds to steps 863 and 864 to exit from step 866. is there.

Thus, by determining whether the temperature T _W of the cooling water of the engine 14 is equal to or higher than a predetermined value,
It is determined whether or not the vehicle has been restarted after a short stop, and if not restarted after a short stop, cool down control is performed for a normal time (first predetermined time). If a restart is to determine the state of the evaporator from the temperature difference between the evaporator temperature T _E and the vehicle interior temperature T _INC,
When the temperature difference is large, the cool down control is performed for the shortest second predetermined time, and when the temperature difference is small, the intermediate third predetermined cool down control can be performed. Can be prevented from freezing,
This can avoid stopping the cooling cycle due to freezing of the evaporator.

[0040]

As described above, according to the present invention, when the vehicle is started, it is determined whether or not the vehicle is started after a short stop. ,
By shortening the time for executing the rapid cool-down control according to the state of the evaporator, it is possible to prevent the evaporator from freezing while maintaining the air conditioning level.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a configuration of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a vehicle air conditioner used in the embodiment according to the present invention.

FIG. 3 is a cross-sectional view showing an example of a variable displacement compressor used in the vehicle air conditioner according to the present invention.

FIG. 4 is a flowchart of a main routine of air conditioning control executed by the microcomputer.

FIG. 5 is a timing chart showing a control state of each control device according to a target blowout temperature.

FIG. 6 is a flowchart illustrating a rapid cool-down control according to the present invention executed by a microcomputer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 14 Running engine 100 Rapid cool-down start determining means 110 Engine cooling water temperature detecting means 120 Restart determining means after a short stoppage 130 Rapid cool-down control means

Claims (1)

(57) [Claims] In a vehicle air conditioner having at least an evaporator for cooling introduced air in an air conditioning duct, a rapid cool down start determination requesting a transition to a rapid cool down control when a heat load is larger than a predetermined value. Means, an engine cooling water temperature detecting means for detecting an engine cooling water temperature, and determining whether or not the engine is to be restarted after a short stop based on the engine cooling water temperature detected by the engine cooling water temperature detecting means. When the restart determination means after the short stop is determined and the restart determination means after the short stop determines that the restart is not the restart after the short stop, the quick cool down control is executed for a predetermined time. When it is determined that the restart is performed after a short stop, the operation time is shortened as compared with the predetermined time when the restart is not performed, and the rapid cooler is stopped. Air conditioning system characterized by comprising a rapid cool-down control means for executing the down control.