JPH05106921A - Air-conditioner - Google Patents

Abstract

PURPOSE:To prevent storage, i.e., the sleep phenomenon as it is called, of liquid refrigerant in a refrigerant compressor without lowering the reliability of a cycle without cost increasing. CONSTITUTION:Control means 7 for controlling operations of a blower 3 and a refrigerant compressor 22 has an outer atmospheric temperature sensor 28 for sensing a temperature of the atmosphere in a vehicle compartment, an atmosphere temperature sensor 29 for sensing a temperature of an atmosphere of a refrigerant evaporator, a compressor drive circuit 31 for driving.stopping the compressor 22, a blower drive circuit 32 for driving.stopping the blower 3, and a microcomputer 33 for outputting a control signal to the driver circuits 31 and 32. The microcomputer 33 outputs an operation signal for operating the blower 3 before the compressor 22 is started if the detected value of the sensor 29 is higher than that of the sensor 28 to the drive circuit 32.

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.

[0002]

2. Description of the Related Art Generally, in a refrigeration cycle used for a vehicle air conditioner, a refrigerant compressor having a large heat capacity is arranged inside an engine room, whereas a refrigerant condenser and a refrigerant evaporator having a small heat capacity are used. The heat exchanger is installed at a position that is easily affected by ambient temperature and solar radiation. Therefore, if the vehicle is left for a long time on a sunny day in winter, in the summer in the mountains, or at night, if the refrigerant evaporator gets warmed after the refrigerant compressor cools down, As the pressure rises slightly, the refrigerant inside the refrigerant evaporator moves to the refrigerant compressor side. Then, by condensing in the refrigerant compressor that is still cold, the liquid refrigerant gradually accumulates in the refrigerant compressor.

If the amount of the liquid refrigerant is large, an abnormally high pressure is generated by the liquid refrigerant, so-called stagnation phenomenon occurs, and abnormal noise is generated from the refrigerant compressor at the time of starting the refrigeration cycle, and there are problems such as valve cracking and galling. cause. Therefore,
2. Description of the Related Art Conventionally, there has been proposed a technique for preventing the inflow of liquid refrigerant by providing an electromagnetic valve on the suction side and a check valve on the discharge side of a refrigerant compressor.

[0004]

However, the use of the solenoid valve or the check valve in the cycle has a problem that the reliability of the cycle may be reduced and the cost may be increased. It was The present invention has been made based on the above circumstances, and an object thereof is vehicle air in which a so-called stagnation phenomenon in which liquid refrigerant accumulates in a refrigerant compressor is prevented without causing deterioration in cycle reliability and cost increase. To provide a harmony device.

[0005]

In order to achieve the above object, the present invention provides a blower duct for introducing blown air into a passenger compartment, and a blower for producing an air flow toward the passenger compartment in the blower duct. And is placed in the air duct,
A refrigerant evaporator of a refrigeration cycle that cools ambient air by heat exchange with a refrigerant, a refrigerant compressor that circulates a refrigerant in the refrigeration cycle, and a control unit that controls the operation of the blower and the refrigerant compressor. In the vehicle air conditioner, the control means has an outside air temperature sensor that detects an outside air temperature of a vehicle compartment and an ambient temperature sensor that detects a temperature around the refrigerant evaporator in the air duct.
When the detected value of the ambient temperature sensor is larger than the detected value of the outside air temperature sensor by a preset value or more, the technical means is to operate the blower before starting the refrigerant compressor. To do.

[0006]

In the vehicle air conditioner of the present invention having the above structure, the blower is activated before the refrigerant compressor is started when the value detected by the ambient temperature sensor is larger than the value detected by the outside air temperature sensor by the set value or more. By doing so, the temperature of the ambient air around the refrigerant evaporator is lowered. As a result, the internal pressure of the refrigerant evaporator decreases, the liquid refrigerant accumulated in the refrigerant compressor flows back to the refrigerant evaporator side, and the liquid refrigerant in the refrigerant compressor decreases. After that, the refrigerant compressor is activated to shift to steady control.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a vehicle air conditioner of the present invention will be described with reference to FIGS. FIG. 1 is an overall configuration diagram of a vehicle air conditioner. This vehicle air conditioner 1 includes a blower duct 2 (hereinafter abbreviated as duct 2) for introducing blown air into a vehicle interior, and a blower 3 and a duct 2 for generating an airflow in the duct 2 toward the vehicle interior. It comprises a refrigerant evaporator 5 of the arranged refrigeration cycle 4, a heater core 6 using engine cooling water as a heat source, control means 7 (described later) for controlling the operation of the air conditioner 1, and the like.

The duct 2 is provided at its upstream end with an inside air introduction port 8 and an outside air introduction port 9 for introducing air into the duct 2, and one of the introduction ports 8 and 9 is closed by an inside / outside air switching damper 10. To be done. The downstream end of the duct 2 is communicated with each of the air outlets 14, 15, 16 opening into the vehicle compartment through each of the branch ducts 11, 12, 13. In addition,
The outlets 14 to 16 are switched by the outlet switching dampers 17 and 18 that operate according to the selected outlet mode.

The outlet mode is a defroster mode in which conditioned air is discharged toward the window glass of the vehicle, a vetilation mode in which conditioned air is discharged mainly toward the upper body of the occupant, and the conditioned air is discharged near the occupant's feet. The heater mode for discharging is set. These outlet modes are set by selectively operating a mode switch 19 (see FIG. 2) provided on a control panel (not shown) in the driver's seat. The temperature control of the blown air is performed by mixing the air passing through the heater core 6 and the air bypassing the heater core 6 with the air mix damper 20 provided on the upstream side of the heater core 6.

The refrigerating cycle 4 receives high-temperature, high-pressure gas compressed by the refrigerant compressor 22 in response to the blowing of a refrigerant compressor 22 and a cooling fan 23 driven by an engine (not shown) via an electromagnetic clutch 21. A refrigerant condenser 24 for condensing and liquefying the refrigerant, a receiver 25 for liquid storage provided downstream of the refrigerant condenser 24, an expansion valve 26 for adiabatically expanding the high-pressure liquid refrigerant flowing from the receiver 25, and a low temperature / low pressure Each functional component of the refrigerant evaporator 5 that evaporates the atomized refrigerant thus formed by receiving the air blown by the blower 3 is connected in a ring shape by the refrigerant pipe 27.

As shown in FIG. 2 (a block diagram showing the structure of the control means 7), the control means 7 is installed downstream of the outside air temperature sensor 28 for detecting the outside air temperature of the vehicle compartment and the refrigerant evaporator 5, and is installed in the refrigerant evaporator. Atmospheric temperature sensor 2 for detecting the atmospheric temperature of 5
9. Various sensors such as a water temperature sensor 30 for detecting the temperature of engine cooling water, a compressor drive circuit 31 for driving / stopping the refrigerant compressor 22, a blower drive circuit 32 for driving / stopping the blower 3, and the various types described above. The microcomputer 33 outputs a control signal to the compressor drive circuit 31 and the blower drive circuit 32 based on the information from the sensors 28 to 30 and the signal from the mode switch 19.

The microcomputer 33 operates by turning on the air conditioner switch 34, and as shown in FIG. 3, after initial setting (step S1), after executing start-up control (step S2), a steady state is established. Control is transferred (step S3). The start-up control causes troubles such as abnormal noise generation and valve cracking due to liquid compression when the liquid refrigerant is accumulated in the refrigerant compressor 22 at the time of starting the refrigeration cycle 4. Therefore, the liquid refrigerant in the refrigerant compressor 22 is controlled. Is a control performed to reduce

Here, the operation of the microcomputer 33 for controlling startup will be described with reference to the flowchart shown in FIG. First, it is determined whether or not the outlet mode is the heater mode (step S20), and in the case other than the heater mode (NO), the detected value TEO of the ambient temperature sensor 29 and the detected value Ta of the outside air temperature sensor 28 are determined. It is determined whether or not the difference (TEO-Ta) is greater than or equal to the set value T (step S2).
1). If TEO-Ta ≧ T (YES), the blower 3
Is output to the blower drive circuit 32 and a built-in timer counter (not shown) is started (step S22).

After the end of the timer counter (after a lapse of a predetermined time), an operation signal for operating the refrigerant compressor 22 is output to the compressor drive circuit 31 (step S23). If TEO-Ta <T in the determination in step S21 (N
O), an operation signal is output to the compressor drive circuit 31 in step S24, and then the blower drive circuit 3 is output in step S25.
2 outputs an operation signal. In the heater mode (YES) in the determination in step S20, it is determined whether the engine cooling water temperature detected by the water temperature sensor 30 is equal to or higher than a predetermined value (for example, 30 ° C.) (step S2).
6) If the engine cooling water temperature is equal to or lower than the predetermined value (NO), the process returns to step S20, and if it is equal to or higher than the predetermined value (YE
In step S), the above step S21 is executed.

Next, the operation of this embodiment will be described. When the air conditioner switch 34 is turned on and the air conditioner 1 is activated, the activation control by the microcomputer 33 is performed. In this start-up control, when the air outlet mode is the heater mode, if air is blown when the engine cooling water temperature is still low, cool air is discharged, which is not preferable in terms of feeling. Therefore, the engine cooling water temperature is a predetermined value (30 ° C).
The air is blown after rising to.

After the engine cooling water temperature reaches a predetermined value,
Alternatively, when the outlet mode is other than the heater mode, the difference (TEO-Ta) between the detected value TEO of the ambient temperature sensor 29 and the detected value Ta of the outside air temperature sensor 28 is compared with the set value T. This is because it is considered that the liquid refrigerant is likely to accumulate in the refrigerant compressor 22 when the difference between the ambient temperature of the refrigerant evaporator 5 and the outside air temperature is large and the ambient temperature of the refrigerant evaporator 5 is high. By comparing the ambient temperature around the refrigerant evaporator 5 with the outside air temperature, it is determined whether or not the liquid refrigerant is accumulated in the refrigerant compressor 22.

Therefore, when TEO-Ta ≧ T, it is judged that the liquid refrigerant is stored in the refrigerant compressor 22, and the blower 3 is operated before the refrigerant compressor 22 is started. As a result, the ambient temperature around the refrigerant evaporator 5 decreases, the liquid refrigerant accumulated in the refrigerant compressor 22 flows back to the refrigerant evaporator 5 side, and the liquid refrigerant in the refrigerant compressor 22 decreases. Blower 3
Is activated and the refrigerant compressor 22 is started after a predetermined time has passed, it is possible to prevent problems such as abnormal noise generation and valve cracking due to liquid compression in the refrigerant compressor 22.

In comparison between the ambient temperature of the refrigerant evaporator 5 and the outside air temperature, when TEO-Ta <T, the liquid refrigerant is not accumulated in the refrigerant compressor 22, or the liquid refrigerant is in a very small amount. Judge that there is, and the refrigerant compressor 22 as it is
There is no problem even if you start. After executing this start-up control, the control shifts to steady-state control.

In this embodiment, the control example in which the timer counter is started together with the operation of the blower 3 and the refrigerant compressor 22 is started after the count is finished is shown. However, after the operation of the blower 3, the surroundings of the refrigerant evaporator 5 are shown. When the difference between the ambient temperature and the outside air temperature becomes less than the set value, the refrigerant compressor 22
May be controlled so as to be activated.

[0020]

According to the vehicle air conditioner of the present invention, when it is determined that the liquid refrigerant is stored in the refrigerant compressor, the air compressor is controlled to operate the blower before the refrigerant compressor is started up. By reducing the amount of liquid refrigerant in the machine, it is possible to prevent problems associated with liquid compression. Therefore, as a measure to prevent the liquid refrigerant from entering the refrigerant compressor, it is not necessary to use a solenoid valve or a check valve as in the conventional case, and the reliability of the cycle is not lowered and the cost is not increased. ..

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a vehicle air conditioner.

FIG. 2 is a block diagram showing a configuration of control means.

FIG. 3 is a flowchart showing the operation of the microcomputer.

FIG. 4 is a flowchart showing start-up control of a microcomputer.

[Explanation of symbols]

 1 Vehicle Air Conditioning Device 2 Blower Duct 3 Blower 4 Refrigeration Cycle 5 Refrigerant Evaporator 7 Control Means 22 Refrigerant Compressor 28 Outside Air Temperature Sensor 29 Ambient Temperature Sensor

Claims (1)

[Claims] 1. A blower duct for introducing blown air into a passenger compartment, a blower for generating an air flow toward the passenger compartment in the blower duct, and a heat for a refrigerant disposed in the blower duct. Vehicle air provided with a refrigerant evaporator of a refrigeration cycle that cools ambient air by replacement, a refrigerant compressor that circulates a refrigerant in the refrigeration cycle, and a control unit that controls the operation of the blower and the refrigerant compressor. In the harmony device, the control unit has an outside air temperature sensor that detects an outside air temperature of a vehicle compartment and an atmosphere temperature sensor that detects a temperature around the refrigerant evaporator in the air duct, and a detection value of the atmosphere temperature sensor. Is larger than the detected value of the outside air temperature sensor by a preset value or more,
An air conditioner for a vehicle, wherein the blower is operated before the refrigerant compressor is activated.