JP2003034133A - Air conditioning system for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioning system for vehicle for performing air conditioning in the interior of a vehicle capable of solving disadvantages of a conventional system that a number of detecting means are required to obtain a detection value necessary for compressor capacity control, which leads to an increase in cost and an increase in sources of failures. SOLUTION: The capacity of a compressor for compressing an air- conditioning coolant gas is switched by a capacity control signal outputted from a controller for controlling the compressor according to a compressor operation rate calculated by use of the compressor ON time and compressor OFF time inputted to the controller. Accordingly, detecting means required for the compressor capacity control can be significantly omitted to reduce the cost and the sources of failures. Consequently, troubles can be thus reduced, and the reliability can be enhanced.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner in which the capacity of a variable displacement compressor for compressing refrigerant gas for air conditioning is controlled in accordance with the operating rate of the compressor. . 2. Description of the Related Art FIG. 3 shows a conventional variable displacement compressor, which controls the displacement of a compressor by changing the displacement control pressure based on detected values of temperature, pressure, solar radiation, etc. detected by various sensors. FIG. 1 is a system configuration diagram of a vehicle air conditioner configured to perform the following. As shown in the figure, the gas refrigerant compressed by the variable capacity compressor 20 is condensed by the condenser 21, and the liquefied liquid refrigerant is supplied to the receiver 22.
Is supplied to the thermal expansion valve 23 via the
3 to adiabatic expansion, evaporate by the evaporator 24, cool by heat absorption at the time of evaporation, and cool the introduced air supplied from the inside / outside air switching damper 27 described later into the vehicle.
The gas refrigerant that has been dehumidified and has absorbed heat by the evaporator 24 is returned to the variable capacity compressor again, is compressed again, and forms a refrigeration cycle that is supplied to the condenser 21. At the entrance of the air flow path where the above-described evaporator 24 is installed and constitutes an indoor unit, there is provided an inside air inlet 25 for taking in the vehicle air (inside air) and an outside air inlet 26 for taking in the outside air. The inside / outside air switching damper 27 for controlling the opening ratio between the inside air introduction port 25 and the outside air introduction port 26 based on a signal from the controller 36 so as to introduce the air into a constant ratio determined by the temperature and the like. Is provided. In the air flow path between the inside / outside air switching damper 27 and the evaporator 24, a blower 28 for blowing the air introduced from the inside / outside air switching damper 27 into the vehicle is provided. Side air flow path,
An air mix damper 29 that opens and closes the air flow path to determine the amount of reheat of the introduced air that has passed through the evaporator 24, a heater 30 that reheats the introduced air whose passing flow rate varies according to the opening and closing of the air mix damper 29, and a heater Mixing the introduced air reheated in 30 with the introduced air that has passed only through the evaporator 24, the introduced air is heated to a temperature suitable for in-vehicle air conditioning,
An air mix chamber 31 for adjusting humidity is provided. [0005] Further, a mode damper 35 is provided on the downstream side of the air mix chamber 31 so as to blow out the introduced air mixed in the air mix chamber 31 toward the vicinity of the occupant's face. FACE duct 3
2. FACE, FOOT, and DEF for controlling the flow rate of the air introduced into the FOOT duct 33 installed to blow out toward the passenger's feet and the DEF duct 34 installed to blow out toward the windshield. The mode is switched. An indoor unit is formed by various devices and members with numbers from the inside air inlet 25 to the mode damper 35. A controller 36 for controlling the operation of the variable capacity compressor 20, the blower 28 and the inside / outside air switching damper 27 includes a temperature or pressure detecting means 37 for the refrigerant gas supplied to the evaporator 24 and a vehicle temperature detecting means 38. , An outside temperature detecting means 39 and an insolation detecting means 40 are provided. The controller 36 determines the compressor capacity from the cooling load of the vehicle obtained from the physical quantities such as the pressure and temperature detected by these detecting means and the cooling capacity of the air conditioner input in advance, and varies the capacity control signal 41. The variable capacity compressor 2 is sent to the capacity compressor 20 and corresponds to the determined compressor capacity.
The ON / OFF control 42 of 0 is performed to control the compressor capacity. That is, generally, the variable displacement compressor 2
In order to switch the compressor capacity of 0, as described above, the refrigerant temperature or pressure in the evaporator 24 is detected, and the capacity control pressure of the variable capacity compressor 20 is changed in accordance with the detected value to thereby change the compressor capacity. Control is performed. Among the detected values used for calculating the cooling load of the vehicle for switching the compressor capacity of the variable capacity compressor 20, the detected values from the temperature / pressure detecting means for detecting the refrigerant temperature in the evaporator 24 are the following. For simplicity, a frost thermostat provided for preventing the evaporator from freezing can be substituted, but a fin thermostat or a pressure sensor for low pressure is required to accurately detect and control the refrigerant state of the evaporator 24. Therefore, in a vehicle air conditioner employing such a variable displacement compressor 20, there is a problem that the cost is increased even in a portion other than the compressor body. Further, when an external variable displacement compressor is used, the temperature inside the vehicle necessary for calculating the cooling load of the variable displacement compressor 20 described above,
Detecting means 38, 39 for detecting the outside air temperature, the amount of solar radiation, etc.
In addition to the detection value from 40, in consideration of various factors such as engine speed and vehicle speed that determine the operating state of the air conditioner, it is difficult to obtain a desired cooling capacity unless compressor capacity control is performed. A variety of sensor information is required, which increases costs and leads to an increase in the number of causes of failure, resulting in even more serious problems. As described above, the external variable displacement compressor 2
0 means that it is difficult to use an external variable displacement compressor 20 for a vehicle air conditioner with a manual vehicle air conditioner because it requires additional various sensors as compared to the variable displacement compressor 20. It is. The advantages of using the variable capacity compressor 20 in the vehicle air conditioner include (1) power saving, (2) reduction in blow-out temperature fluctuation, (3) reduction in engine load torque, and the like. In addition, the control method at the time of mounting is very complicated, and the cost is high. In general, it is often used for luxury cars. SUMMARY OF THE INVENTION The present invention switches the compressor capacity of a variable displacement compressor in order to solve the problem of the conventional vehicle air conditioner using the above variable displacement compressor. Therefore, by using a simple type variable displacement compressor that can control the compressor capacity based on the compressor operating rate without using the detected value of the refrigerant temperature or pressure in the evaporator, the same as the conventional movable displacement compressor The conventional movable capacity does not require the temperature / pressure detecting means for accurately detecting and controlling the refrigerant state of the evaporator, and can enjoy the advantages such as power saving, reduction of the blowout temperature fluctuation, and reduction of the engine load. Compared to using a compressor, the cost is lower. An object of the present invention is to provide a vehicle air conditioner capable of performing capacity control. [0012] Therefore, the vehicle air conditioner of the present invention has the following means. A compressor for compressing an air conditioning refrigerant gas of a vehicle air conditioner mounted on a vehicle is input from a compressor operating state to a controller for controlling the compressor based on a compressor ON time and a compressor OFF time. The compressor capacity is switched by the capacity control signal output from the controller according to the compressor operating rate defined by the ratio of the ON time to the addition time of the compressor ON time and the compressor OFF time. [0013] This makes it possible to calculate the cooling load required for controlling the compressor capacity, in particular, without using the detected value from the detecting means such as the refrigerant temperature or pressure in the evaporator, without using the detected value of the compressor capacity. The control pressure can be changed. Therefore, the installation of the detection means, which is necessary for the operation control of the compressor, can be largely omitted, the cost can be reduced as compared with the conventional air conditioner for a vehicle, and troubles due to the failure of the detection means and the like can be reduced. And can be highly reliable. An embodiment of a vehicle air conditioner according to the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a vehicle air conditioner that controls the capacity of an external step type variable displacement compressor as a first embodiment of the vehicle air conditioner of the present invention. The outline of the equipment of the vehicle air conditioner of the present embodiment is the same as the equipment of the conventional vehicle air conditioner shown in FIG. 3 except for the variable capacity compressor and the controller. As shown in the figure, in the vehicle air conditioner of the present embodiment, the gas refrigerant compressed by the variable capacity compressor 1 is condensed by the condenser 2 and the receiver 3 receives the liquid refrigerant liquefied by the condenser 2. Adiabatic expansion is performed by the temperature type expansion valve 4 via the evaporator 5, and after evaporating by the evaporator 5, the gas refrigerant absorbed from the introduced air passing through the evaporator 5 is returned to the variable capacity compressor 1 again to constitute a refrigeration cycle apparatus. are doing. Further, an inside / outside air switching damper 7 for switching the inside / outside air introduction port 6 and the outside air introduction port 8 by opening and closing, a blower 9 for blowing the introduced air determined by switching the inside / outside air switching damper 7, and a blower 9. An evaporator 5 for cooling and dehumidifying the introduced air, an air mix damper 10 for determining a reheat amount of the introduced air passing through the evaporator 5,
A heater 11 for reheating the introduced air passing according to the opening of the air mix damper 10, an air mix chamber 12 for mixing the introduced air passed only through the evaporator 5 and the introduced air passed through the heater 11, and an air mix chamber A FACE duct 13 for blowing air introduced from the air supply 12 toward the occupant's face and a FOO duct for blowing air introduced from the air mix chamber 12 toward the occupant's feet.
A T duct 14, a DEF duct 15 for blowing out the air introduced from the air mix chamber 12 toward the windshield, and a communication between the air mix chamber 12 and any one of the FACE duct 13, the FOOT duct 14, and the DEF duct 15. , Air conditioning status FACE, FOOT, DEF
An indoor unit is constituted by the mode damper 16 for switching any of the modes. The controller 17 of the present embodiment sends a displacement control signal 18 to the variable displacement compressor 1 so as to switch the compressor displacement and control the compressor displacement in accordance with the compressor operating rate defined by the following equation. , ON / OFF control 19 is performed. [Equation 1] The compressor capacity control based on the compressor operating rate is performed as shown in FIG.
First, after the air conditioner switch is turned on, time measurement is started from the first time the compressor 1 is turned off, the compressor is turned on, and the compressor ON time until the compressor is turned off and the compressor OF
The F time is measured, and the compressor operating rate is calculated by the above equation. The full load operation is performed until the start of the calculation of the compressor operation rate to prevent uncooling during cool down. For example, as shown in FIG. 2, in the variable displacement compressor 1 which is operated with a two-step capacity of partial load / full load, full load operation is performed until the operation rate becomes α%, When it cools down and the operation rate drops below α%, switch to partial load operation,
In addition, idling operation time increases during traffic jams, etc., the temperature inside the vehicle increases, and the operating rate at partial load capacity becomes β.
When the percentage is over, the system is switched to full load operation. When the compressor capacity is controlled based on the compressor operating rate, the compressor capacity is controlled as follows. (1) When the vehicle speed and the engine speed are high, the compressor operating rate becomes small, so that the partial load operation is performed. (2) When the vehicle speed and the engine speed are low, the compressor operating rate becomes large. When full load operation is performed, (3) when the cooling load is large, the compressor operation rate is increased, so that the full load operation is performed. (4) When the cooling load is further reduced, the compressor operation rate is reduced, so that the partial load operation is performed. It becomes. Thus, in the partial load capacity,
Since the operation is always ON / OFF, the compressor capacity control according to the capacity and heat load of the air conditioner can be automatically performed without operating due to insufficient cooling capacity. Can be used. Further, according to the vehicle air conditioner of the present embodiment, the compressor capacity can be controlled based on the compressor operating rate only by adding the compressor operating rate calculating function to the controller 17, and the low-pressure refrigerant pressure sensor, the fin It is not necessary to add a new sensor for controlling compressor capacity such as thermo, and power saving can be easily achieved using a variable capacity control compressor. It can be realized at low cost. In addition, it is difficult to adopt a manually controlled vehicle air conditioner.For an external variable displacement compressor, it is possible to control the compressor capacity in consideration of the cooling load and the capacity of the air conditioner without adding various sensors. become. As described above, according to the vehicle air conditioner of the present invention, in a vehicle air conditioner for performing in-vehicle air conditioning, a compressor for compressing a refrigerant gas for air conditioning controls the compressor. Input to the controller,
According to the compressor operating rate calculated using the compressor ON time and the compressor OFF time, the compressor capacity is switched by the capacity control signal output from the controller. Thus, the installation of the detecting means, which is necessary for controlling the operation of the compressor, can be largely omitted, the cost can be reduced, the causes of the failure can be reduced, the troubles associated therewith can be reduced and the reliability can be increased. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a vehicle air conditioner that controls the capacity of an external step type variable displacement compressor as a first embodiment of the vehicle air conditioner of the present invention; FIG. 3 is a diagram showing a compressor operating rate and compressor capacity switching. FIG. 3 is a configuration diagram of a vehicle air conditioner that performs capacity control of a conventional variable capacity compressor. [Description of Signs] 1 Variable capacity compressor 2 Condenser 3 Receiver 4 Thermal expansion valve 5 Evaporator 6 Inside air inlet 7 Inside / outside air switching damper 8 Outside air inlet 9 Blower 10 Air mix damper 11 Heater 12 Air mix chamber 13 FACE duct 14 FOOT Duct 15 DEF duct 16 Mode damper 17 Controller 18 Capacity control signal 19 ON-OFF control 20 Variable capacity compressor 21 Capacitor 22 Receiver 23 Thermal expansion valve 24 Evaporator 25 Inside air inlet 26 Outside air inlet 27 Inside / outside air switching damper 28 Blower 29 Air Mix damper 30 Heater 31 Air mix chamber 32 FACE duct 33 FOOT duct 34 DEF duct 35 Mode damper 36 Controller 37 Temperature / pressure detecting means 38 Vehicle temperature detecting means 39 Outside temperature detecting means 40 Solar radiation detecting means 41 Capacity control signal 42 ON / OFF control

Claims (1)

Claims 1. An air conditioner for a vehicle mounted on a vehicle and performing air conditioning in the vehicle, comprising: a compressor for compressing a gas refrigerant for air conditioning; and a controller for controlling the compressor. The compressor according to a compressor operating rate calculated using the input compressor ON time and compressor OFF time,
By the capacity control signal output from the controller,
An air conditioner for a vehicle, wherein a compressor capacity is switched.