JP2796456B2 - 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 an air conditioner for a vehicle.

[0002]

2. Description of the Related Art One example of a conventional vehicle air conditioner is shown in FIG.
Is shown in An air inlet 13 and an outside air inlet 14 are formed on the upstream side of the casing 12 of the air conditioner 10, and a face outlet 20, a defrost outlet 23, and a foot outlet 24 are formed on the downstream side. . The inside air suction port 13 and the outside air suction port 14 are switched by an inside / outside air switching damper 15. Face outlet 20, Defrost outlet 23 and Foot outlet
24 is opened and closed by blow mode switching dampers 25, 26, 27, respectively. Blower 16 and evaporator in casing 12
, An air mix damper 18 and a heater 19 are provided. The evaporator 17 forms a refrigerant circuit by being connected to a compressor 28, a condenser 29, a receiver 30, an expansion valve 31 and the like via a refrigerant pipe.
And a driving engine 35 via a magnet clutch 34. The cooling water of the traveling engine 35 circulates through the heater 19, and the amount of air passing through the heater 19 is changed by the opening of the air mix damper 18.

When the blower 16 is driven, an inside / outside air switching damper
The interior air or the outside air is supplied to the casing 12 from the inside air suction port 13 or the outside air suction port 14 selected by switching the
After being sucked into and blown by the blower 16, it is cooled by passing through the evaporator 17. Then
This air is diverted by the air mix damper 18, a part of which is heated by passing through the heater core 19, and then mixed with the remaining air bypassing the heater 19 to become conditioned air at a predetermined temperature. The conditioned air is blown into the vehicle cabin from any one or two of the face outlet 20, the defrost outlet 23, and the foot outlet 24 selected by opening and closing the blowout mode switching dampers 25, 26, 27. .

Reference numeral 11 denotes a control device comprising a microcomputer, which has an I / 0 port, a multiplexer, an A / D converter, a central processing unit CPU, a read-only memory ROM, a random access memory RAM, and the like. The detection values of the potentiometer 41 for detecting the opening of the air mix damper 18, the solar radiation sensor 42, the outside air temperature sensor 43, the room temperature sensor 44, the evaporator 17 or the evaporator temperature sensor 45 for detecting the air temperature at the outlet thereof are as follows. It is input to the control device 11. In addition, a control panel 46 installed in front of the driver's seat includes an operation switch for the air conditioner 10, a switch for blowing mode, and an inside / outside air switching damper.
15 changeover switches, a cooling operation switch for setting the cooling operation, an air volume changeover switch for switching the rotation speed of the blower 16,
An AUTO switch for automatically controlling the air-conditioning control, a room temperature setting device for arbitrarily setting the temperature in the vehicle compartment, and the like are provided, and their outputs are also input to the control device 11. The output of the control device 11 is supplied to the compressor 2 via a driver (not shown).
8, magnet clutch 34, blower 16, dampers 15, 18, 2
5, 26, 27 are sent to motor actuators 56, 57, 58, etc. to control their operation.

FIG. 3 is a longitudinal sectional view of the compressor 29. When the magnet clutch 34 comes into contact, the orbiting scroll 65 is driven via a orbiting drive mechanism including a drive shaft 61, an eccentric pin 62, a drive bush 63, an orbiting bearing 64, etc., and the orbiting scroll 65 is a rotation preventing mechanism that also serves as a thrust bearing 66
The orbital orbital motion is prevented while rotating.
Then, the suction chamber 69 is inserted into the compression chamber 68 limited by engaging the orbiting scroll 65 and the fixed scroll 67.
The gas inside is sucked and compressed by the orbiting movement of the orbiting scroll 65 while the compression chamber 68 moves toward the center of the spiral while reducing the volume, and is discharged from the discharge port 70 through the discharge pipe 71.

The compressor 28 has a bypass piston 72 for controlling the capacity of the compressor 28 by bypassing the gas being compressed in the compression chamber 68 to the suction chamber 69 through the bypass port 73, and discharge pressure and suction pressure. And a control valve 74 for generating a control pressure for operating the bypass piston 72 by sensing the pressure, and the capacity of the compressor 28 is controlled by a capacity control mechanism including the bypass piston 72 and the control valve 73. Compressor 2
A discharge gas temperature sensor 48 for detecting the temperature of the discharge gas discharged from the compressor 8 is provided in the vicinity of the discharge part of the refrigerant gas discharge part of the compressor 28 or the refrigerant pipe connected thereto. When the temperature of the evaporator 17 detected by the evaporator temperature sensor 45 reaches the frost limit temperature, the magnet clutch 34 is disconnected by the output from the control device 11, and the compressor 28 is stopped.

[0007]

In the above-mentioned conventional air conditioner for a vehicle, when the capacity control rate of the compressor 28 increases, the bypass amount increases, and the efficiency of the compressor 28 decreases accordingly. The temperature of the discharge gas discharged from the compressor 28 increases. Then, when the vehicle is running at a high speed or the like, the temperature of the discharged gas increases greatly, so that the discharged gas temperature thermoswitch is activated to stop the air conditioner for the vehicle. Then, since it takes time until the discharge gas temperature thermoswitch returns and the vehicle air conditioner resumes operation, there is a problem that the air conditioning feeling in the vehicle compartment is impaired.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and its gist is to provide a bypass for controlling the capacity by bypassing gas in a compressor to a suction side. An air conditioner for a vehicle, comprising a compressor with a type capacity control mechanism, wherein when the temperature of the evaporator reaches the frost limit temperature, the compressor is stopped.
A discharge gas temperature sensor for detecting the temperature of the discharge gas discharged from the compressor is provided, and control means for increasing the capacity of the compressor when the temperature detected by the discharge gas temperature sensor becomes equal to or higher than a set value is provided. A vehicle air conditioner characterized by the above-mentioned.

[0009]

According to the present invention, since the above structure is provided, when the temperature of the discharge gas discharged from the compressor exceeds a set value, the capacity of the compressor increases, the bypass amount decreases, and the discharge gas The rise in temperature is suppressed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIG. The evaporator temperature detected by the evaporator temperature sensor 45 is input to the comparing means 61 of the control device 60, where the setting means
The temperature is compared with the set temperature input from 62, that is, the temperature at which frost adheres to the evaporator 17 (hereinafter, referred to as a frost limit temperature). Then, when the evaporator temperature becomes equal to or higher than the frost limit temperature, the comparing means 61 outputs to the clutch 34 to disconnect it, and the compressor 28 stops. Discharge gas temperature sensor
48 is provided in the discharge pipe of the compressor 28, the temperature of the discharge gas detected by the discharge gas temperature sensor 48 is also input to the comparison means 63 of the control device 60, and here the set value input from the setting means 64 Be compared. When the discharge gas temperature becomes equal to or higher than the set value, the comparing means 63 outputs the same to the capacity determining means 65. The capacity determining means 65 determines the capacity of the compressor 28 according to the control rule or control map inputted from the storage means 66, and the result of the determination is output to the compressor 28 with the capacity control mechanism.

Thus, the capacity of the compressor 28 increases, the bypass amount decreases, and the discharge gas temperature decreases. When the capacity of the compressor 28 increases, the temperature of the evaporator 17 decreases.However, when the temperature of the evaporator 17 reaches the frost limit temperature, the clutch 34 is disengaged.
Since the stop is repeated, adhesion of frost to the evaporator 17 can be prevented.

[0012]

According to the present invention, when the temperature of the discharge gas discharged from the compressor exceeds a set value, the capacity of the compressor increases, the bypass amount decreases, and the rise in the temperature of the discharge gas is suppressed. You. As a result, the air conditioner can be prevented from being stopped for a long time by the operation of the blowout gas temperature thermoswitch, so that the air conditioning feeling can be prevented from deteriorating.
Further, the evaporator temperature decreases due to an increase in the capacity of the compressor. However, when the evaporator temperature reaches a predetermined frost limit temperature, the compressor stops, so that a problem can be prevented beforehand due to frost adhering to the evaporator.

[Brief description of the drawings]

FIG. 1 is a control block diagram showing one embodiment of the present invention.

FIG. 2 is a system diagram of a conventional air conditioner.

FIG. 3 is a longitudinal sectional view of a compressor with a capacity control mechanism.

[Explanation of symbols]

 28 Compressor with capacity control mechanism 34 Clutch 60 Control device 45 Evaporator temperature sensor 48 Discharge gas temperature sensor 61, 63 Comparison means 62, 64 Setting means 65 Capacity determination means 66 Storage means

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kenichi Terauchi 3-1-1 Asahi-cho, Nishibiwajima-cho, Nishi-Kasugai-gun, Aichi Prefecture Mitsubishi Heavy Industries, Ltd. Aircon Works (58) Fields surveyed (Int. Cl. ⁶ , (DB name) B60H 1/32

Claims (1)

(57) [Claims] 1. A vehicle comprising a compressor with a bypass-type capacity control mechanism for controlling the capacity by bypassing gas in the compressor to a suction side, wherein the compressor is stopped when the temperature of an evaporator reaches a frost limit temperature. In the air conditioner for use, a discharge gas temperature sensor for detecting the temperature of the discharge gas discharged from the compressor is provided, and when the temperature detected by the discharge gas temperature sensor exceeds a set value, the capacity of the compressor is increased. An air conditioner for a vehicle, comprising a control unit.