JPH1044759A - Air conditioner for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exclude the bad influence to the startability and travel feeling of an engine for vehicle travelling, in accompany with the starting of an air conditioner, and prevent the compression of the liquid at the start of a compressor. SOLUTION: The discharge capacity of a compressor is controlled to be minimum for a specific time from the connection of an electromagnetic clutch 6 for starting the compressor 1, when the compressor 1 is started, and further the discharge capacity of the compressor 1 is controlled to be minimum by controlling a capacity controlling mechanism, when the compressor 1 is stopped by the disconnection of the electromagnetic clutch 6. The capacity controlling mechanism is controlled on the basis of a signal from a sensor means for sensing the temperature of the air of a surface or an outlet of an evaporator 5 which copes with the air conditioning load, to control the discharge capacity of the compressor 1.

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, and more particularly, to a control of a displacement of a compressor of the air conditioner for a vehicle when starting and stopping the compressor.

[0002]

2. Description of the Related Art A conventionally known vehicle air conditioner is shown in FIG.
, The compressor 120, the condenser 102, the liquid receiver 10
3. It has a refrigeration cycle composed of an expansion valve 104 and an evaporator 105. The compressor 120 includes the electromagnetic clutch 1
06, a belt 107 and a pulley 108 to drive the vehicle by an engine 109 for running the vehicle.

However, in a known vehicle air conditioner, when the ignition switch 117 is turned on and the engine 109 is started with the air conditioner switch 116 turned on, the relay 115 for connecting and disconnecting the electromagnetic clutch 106 is activated. Is turned on, the electromagnetic clutch 106 is connected,
Since the compressor 120 is started together with the engine 109 and a relatively large load is applied to the engine 109, the engine 1
09 startability deteriorates. Also, when the air conditioner switch 116 is turned on during running after the engine 109 is started, a large compressor starting torque is applied to the engine 109 at the moment when the electromagnetic clutch 106 is connected. There was a drawback that the running feeling deteriorated due to the occurrence.

[0004] In order to eliminate such disadvantages,
Japanese Patent Publication No. 1-27893 and Japanese Patent Publication No. 27894
The one described in the official gazette was devised. In this air conditioner, the capacity of a compressor in a conventionally known air conditioner is controllable, an engine start is detected, the compressor is controlled to a small capacity, an electromagnetic clutch is connected, and the compressor is operated. It is intended to be started.

[0005]

However, also in this device, the capacity of the compressor is reduced only when the electromagnetic clutch is connected, and thereafter, the capacity is controlled in accordance with the degree of cooling of the evaporator, and the discharge capacity is rapidly increased. As a result, the liquid refrigerant accumulated in the compressor and in the compressor suction pipe is rapidly compressed, generating excessive pressure, generating loud noise and vibration, and the compressor may be damaged. As described above, in the conventionally known vehicle air conditioner, the starting torque at the time of starting the compressor is applied to the engine as a relatively large load, so that the startability of the engine and the running feeling are deteriorated. In addition, the invention for solving this problem also has a problem that liquid compression occurs immediately after the compressor is started, which may cause noise, vibration, or damage to the compressor.

Accordingly, the present invention has been made in view of such problems, and an object of the present invention is to eliminate the adverse effects on the startability and running feeling of a vehicle running engine associated with the start of an air conditioner. An object of the present invention is to provide an air conditioner that prevents liquid compression at the time of starting a compressor.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, a compressor which receives a driving force of a vehicle driving engine via an electromagnetic clutch, and a compressor built in the compressor. A vehicle air conditioner having a displacement control mechanism for controlling the displacement of the compressor by means of a compressor and a drive means for driving the displacement control mechanism, wherein when the electromagnetic clutch is connected, the compressor operates for a predetermined time from the connection of the electromagnetic clutch. And the discharge capacity of the minimum capacity, at the time of the electromagnetic clutch disconnection,
The driving means is driven to minimize the discharge capacity of the compressor.

According to the second aspect of the present invention, during a steady operation, the drive unit receives a signal from a sensing unit that senses the temperature of the evaporator surface, evaporator outlet air, etc. corresponding to the air conditioning load of the air conditioner. To control the discharge capacity of the compressor.

Therefore, in the control device for a vehicle air conditioner according to the present invention, when the electromagnetic clutch for transmitting the driving force of the vehicle running engine to the compressor is connected (that is, when the air conditioner is started). ), By setting the discharge capacity of the compressor to a minimum capacity for a predetermined time after this connection, the starting torque of the compressor is reduced to reduce the load applied to the engine, and at the same time, the compressor is accumulated in the compressor and the suction pipe of the compressor. The liquid refrigerant is slowly discharged to prevent refrigerant liquid compression.
Further, when the electromagnetic clutch is disengaged (that is, when the air conditioner is stopped), the drive means is driven to stop the discharge capacity of the compressor with the minimum capacity, thereby always keeping the discharge capacity of the compressor at the time of restart at the minimum. It can be.

In the air conditioner for a vehicle according to the second aspect, during a steady operation after the air conditioner is started, a signal from the temperature sensing means for sensing the temperature of the evaporator surface or the evaporator outlet air corresponding to the air conditioning load. In response to this, the displacement of the compressor is controlled in accordance with the air conditioning load in the vehicle, so that the vehicle interior can be maintained comfortably.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in an air conditioner for a vehicle will be described below with reference to FIGS.
FIG. 1 is a schematic diagram of a system of a vehicle air conditioner and a control device thereof according to the present embodiment. The refrigeration cycle in the air conditioner according to the present embodiment includes a compressor 1, a condenser 2, a liquid receiver 3, an expansion valve 4, an evaporator 5 having a capacity control mechanism.
It is composed of The refrigerant gas compressed and discharged by the compressor 1 enters the condenser 2 and is cooled and condensed and liquefied by running air or cooling air sent from a cooling fan (not shown). The liquefied refrigerant is supplied to the expansion valve 4 via the receiver 3.
And expand under reduced pressure. The gas-liquid two-phase refrigerant exchanges heat with the air inside or outside the vehicle blown by the blower 10 driven by the motor in the evaporator 5, cools the air, and the refrigerant itself evaporates and vaporizes. The vaporized refrigerant is sucked into the compressor 1 and a cycle is established.

The compressor 1 is driven by a vehicle traveling engine 9 via an electromagnetic clutch 6, a belt 7, and a pulley 8. Reference numeral 14 denotes a control device, 15 denotes an electromagnetic relay for connecting and disconnecting an electromagnetic clutch, 16 denotes a start / stop switch of an air conditioner, 17 denotes an ignition switch for starting an engine, and 18 denotes a vehicle-mounted battery. The electromagnetic clutch 6 is connected to a battery 18 as a power supply via a contact of an electromagnetic relay 15 and a start / stop switch 16 and an ignition switch 17 of the air conditioner. The electromagnetic coil of the electromagnetic relay 15 is
It is configured to be excited based on the control of.

Reference numeral 11 denotes a ventilation casing of a vehicle air conditioner, in which a motor-driven blower 10 and an evaporator 5 are provided, and air sent from the blower 10 is supplied to the evaporator 5.
After being cooled by exchanging heat, the air is reheated by a heater unit (not shown), and the amount of the reheat is adjusted to be air at a suitable temperature and blown out from an outlet in the vehicle. Reference numeral 19 denotes a temperature sensor as sensing means for sensing the surface temperature of the evaporator 5 or the air temperature immediately after passing through the evaporator 5 which changes in accordance with the air conditioning load of the present air conditioner during steady operation. 5 or the evaporator 5 in the ventilation casing 11
It is provided at the position immediately after passing. Further, the temperature sensor 19 also serves as a temperature sensor for detecting freezing of the evaporator 5.

Here, a compressor 1 having a built-in capacity control mechanism is provided.
Will be described in more detail with reference to FIG. FIG. 2 shows a configuration diagram of a compressor having a scroll type bypass-unloading type capacity control mechanism. The electromagnetic clutch 6 for transmitting the driving force of the vehicle running engine 9 to the compressor 1 is provided by the electromagnetic clutch 6 shown in FIG.
The drive shaft 61 of the compressor 1 is used as an output shaft as shown in FIG.
A pulley 33 connected to the traveling engine 9 by the belt 7 and an electromagnetic coil 32 for intermittently rotating the pulley 33 to the drive shaft 61 are provided. Therefore, when the electromagnetic clutch 6 is connected, the driving force of the engine 9 transmitted to the pulley 33 is transmitted to the driving shaft 61 of the compressor 1.

In the scroll type compressor 1, a pair of orbiting scrolls 65 and fixed scrolls 66 are engaged with each other, and a compression chamber 68 is formed as a crescent-shaped closed space between the scrolls 65 and 66. As described above, the driving force of the engine 9 transmitted to the drive shaft 61 is transmitted to the orbiting scroll 65 via the drive bush 63 as described above. And this compressor 1
As the orbiting scroll 65 revolves orbiting,
Utilizing that the crescent-shaped compression chamber 68 decreases in volume while moving from the periphery to the center, the refrigerant gas is sucked in from the periphery and compressed, and the fixed scroll 6 is compressed.
6 is discharged from a discharge port provided at the center of the nozzle.

Next, a capacity control mechanism according to the present invention will be described. As described above, the volume of the compression chamber 68 changes on the end plate 67 on the fixed scroll side 66 as the orbital scroll of the orbiting scroll 65 revolves.
%, And bypass holes 70 and 73 communicating with the compression chamber 68 are provided at the position where the pressure becomes 0% and within the discharge port where the pressure becomes 0%. Further, the bypass holes 70 and 73 are provided inside the end plate 67 of the fixed scroll 66. Along the direction in which the bypass holes 7 are arranged.
A bypass cylinder 74 is provided for communicating between the suction chambers 0 and 73 and the suction chamber 69, and a substantially cylindrical bypass piston 75 is slidably fitted in the bypass cylinder 74 with its rotation stopped. Also, the bypass piston 74
Has an intermediate wall 78 in the middle of the cylindrical shape as shown in FIG. 3, and the front and rear of the intermediate wall 78 are communicated by a communication hole 79. In the displacement control mechanism, the opening and closing and opening of the bypass holes 70 and 73 are adjusted by the sliding operation of the bypass piston 75, and the opening and closing and the adjustment of the opening allow the suction chamber 69 to move from the middle of compression in the compression chamber 68. It is configured such that the amount of refrigerant gas to be bypassed to is controlled.

Next, the driving means of the capacity control mechanism will be described. An end plate 67 adjacent to the end of the bypass cylinder 74 is provided with a motor housing chamber coaxial with the bypass cylinder 74 and formed of a cylindrical concave portion, and a stepping motor 76 is housed in the motor housing room. As shown in FIG. 3, a motor shaft 77 composed of a screw shaft projects from the center of the end face of the stepping motor 76 facing the bypass cylinder 74, and the motor shaft 77 is connected to an intermediate wall of the bypass piston 75. The bypass piston 75 slides freely in the bypass cylinder 74 by the rotation of the stepping motor 76, and the amount of linear movement of the bypass piston 75 is determined by the rotation angle of the stepping motor 76. It is configured as follows.

The stepping motor 76 is driven by a pulse supplied from the pulse generator 13 (see FIG. 1), and its rotation angle is determined according to the number of pulses supplied from the pulse generator 13. I have. Therefore, by controlling the number of pulses transmitted from the pulse generator 13, the rotation speed of the stepping motor 76 is controlled, and the position of the bypass piston 75 is controlled. The pulse generator 13 is connected to a power supply via an ignition switch 17. When the ignition switch 17 is turned on, an initialization operation described later is performed for a predetermined time to generate a predetermined number of pulses. I do. After this time has elapsed, a pulse is transmitted based on a command from the control device 14. Further, when the start / stop switch 16 of the air conditioner is turned off and the control device 14 is not energized, the same number of pulses as in the initialization operation are transmitted.

FIG. 3 shows the bypass piston 75 at two positions. That is, the left half of the bypass piston 75 indicates a state in which the bypass piston 75 is close to the stepping motor 76,
5 shows a state in which the bypass piston 75 is separated from the stepping motor 76. As mentioned above,
The driving means of the capacity control mechanism is mainly constituted by the stepping motor 76 and the pulse generator 13.

Therefore, when a partial load operation is performed by the capacity control mechanism, the number of pulses transmitted from the pulse generator 13 is controlled to control the position of the bypass piston 75, and the opening areas of the bypass holes 70 and 73 are controlled. Is controlled, the refrigerant gas in the compression chamber 68 flows through the bypass hole 7.
0, 73, the amount returned to the suction chamber is controlled.
The amount of the discharged refrigerant gas, that is, the flow rate of the refrigerant circulating in the refrigeration cycle is controlled.

Next, the control device 14 will be described. The control device 14 transmits an excitation signal for exciting the electromagnetic relay 15 and controls the energization of the relay 15,
This is for transmitting a pulse transmission command to the pulse generator 13, that is, for transmitting a capacity control signal, and is connected to a vehicle-mounted battery 18 via an ignition switch 17, as shown in FIG. More specifically, the control device 14 detects the necessity of connection of the electromagnetic clutch 6 based on the signal from the temperature sensor 19 and the closing operation of the start / stop switch 16 of the air conditioner, and excites the electromagnetic relay 15. A signal is transmitted, that is, an electromagnetic clutch connection signal is transmitted, and the electromagnetic relay 15 is excited to connect the electromagnetic clutch 6. Further, in response to the transmission of the electromagnetic clutch connection signal, the pulse transmission command (transmission of the capacity control signal) to the pulse generator 13 is stopped for a predetermined time from the connection of the electromagnetic clutch 6. Also, the signal from the temperature sensor 19 detects that the evaporator 5 has dropped below the freezing temperature, and detects that the electromagnetic clutch 6 should be disconnected. A disconnection signal is transmitted, the excitation of the electromagnetic relay 15 is stopped, and the electromagnetic clutch 6 is disconnected. Also, in response to the electromagnetic clutch disconnection signal, it instructs the pulse generator 13 to transmit a pulse that minimizes the displacement of the compressor 1. Further, the control device 14 receives a signal corresponding to a change in the air-conditioning load during a steady operation of the air-conditioning device from a temperature sensor 19 as a sensing means for sensing the surface temperature of the evaporator 5 or the temperature of the air at the outlet of the evaporator 5. And the number of pulses generated from the pulse generator 13 is controlled by the signal to control the displacement of the compressor 1.

Next, the operation of the vehicle air conditioner configured as described above will be described. When the ignition switch 17 is turned on when the vehicle is driven, the traveling engine 9 starts, and the pulley 33 of the electromagnetic clutch 6 of the compressor 1 rotates via the pulley 8 and the belt 7. The pulse generator 13 is also energized, and the pulse generator 13 performs an initialization operation. That is, a predetermined number of pulses are sent from the pulse generator 13 to the stepping motor 76, the bypass piston 75 is moved to a position where the compressor 1 has the minimum capacity, and the capacity control mechanism is initialized. The pulse generator 13 does not receive a signal from the control device 14 during this initialization operation.

Also, when the ignition switch 17 is turned on or after the air conditioner switch 16 is turned on, the control device 14 is energized.
An electromagnetic clutch connection signal is transmitted to excite the electromagnetic relay 15 to connect the electromagnetic clutch 6. The control device 14
Receives the transmission of the electromagnetic clutch connection signal, and stops transmitting the capacity control signal to the pulse generator 13 for a predetermined time from that time. Therefore, the ignition switch 17
When the switch 16 of the air conditioner is turned on at or after turning on, the contact of the electromagnetic relay 15 is closed, the electromagnetic clutch 6 is connected, and the compressor 1 is operated. The compressor 1 is started from the state of the minimum capacity by the initialization of the compressor 1 or when the discharge capacity of the compressor 1 is minimized and stopped when the electromagnetic clutch disconnection signal is generated, so that the starting torque of the compressor 1 And the load on the engine 9 is reduced. Also, when the compressor 1 is started, as described above, the transmission of the capacity control signal to the pulse generator 13 is stopped for a predetermined time, and the minimum capacity operation of the compressor 1 is continued for a predetermined time. 1
The liquid refrigerant accumulated inside and in the suction pipe of the compressor 1 and the like is slowly discharged, and after the discharge is completed, a steady operation is started, so that liquid compression is prevented.

After the compressor 1 is started, after the predetermined time has elapsed and the air conditioner has entered a steady operation, the control device 14 serves as sensing means for sensing the temperature of the surface of the evaporator 5 or the air at the outlet of the evaporator. Based on the signal from the temperature sensor 19, the number of pulses generated from the pulse generator 13 to the stepping motor 76 is controlled, and the capacity of the compressor 1 is controlled according to the air conditioning load in the vehicle.

Further, during the normal operation of the air conditioner, the control device 14 senses from the signal from the temperature sensor 19 that the temperature of the evaporator 5 has become lower than the freezing point, and determines the necessity of disconnecting the electromagnetic clutch 6. If detected, an electromagnetic clutch disconnection signal is transmitted, the excitation of the electromagnetic relay 15 is stopped, the electromagnetic clutch 6 is disconnected, the operation of the compressor 1 is stopped, and the operation of the air conditioner is stopped. Further, in response to the transmission of the electromagnetic clutch disconnection signal, the control device 14 instructs the pulse generator 13 to transmit to the stepping motor 76 a pulse at which the discharge capacity of the compressor 1 becomes the minimum capacity. Therefore, the displacement control mechanism of the compressor 1 is driven by the driving means to be in a state where the discharge capacity of the compressor 1 is set to the minimum capacity. During this stop period, the compressor 1 sets the discharge capacity to the minimum capacity. Is kept as it is.

Thereafter, when the temperature of the evaporator 5 rises and the temperature sensor 19 senses a temperature higher than the freezing point, the detection means determines the connection of the electromagnetic clutch 6 based on a signal from the temperature sensor 19, and Sends the electromagnetic clutch connection signal,
The electromagnetic relay 15 is excited to connect the electromagnetic clutch 6.
Upon receiving the transmission of the electromagnetic clutch connection signal, the control device 14 transmits the pulse generator 1 for a predetermined time from that time.
The transmission of the capacity control signal to No. 3 is stopped. Therefore, in this case, the contact of the electromagnetic relay 15 is closed, and the electromagnetic clutch 6
Is connected to the compressor 1, and the compressor 1 is turned on. However, as described above, when the discharge capacity of the compressor 1 is set to the minimum capacity when the electromagnetic clutch disconnection signal is generated, the compressor 1 is stopped. , The starting torque of the compressor 1 is reduced, and the load on the engine 9 is reduced.
Also, when the compressor 1 is started, as described above, the transmission of the capacity control signal to the pulse generator 13 is stopped for a predetermined time, and the minimum capacity operation of the compressor 1 is continued for a predetermined time. The liquid refrigerant that has accumulated in the compressor 1 and in the suction pipe of the compressor 1 is slowly discharged, and after the discharge is completed, a steady operation is started, so that liquid compression is prevented.

Next, when only the switch 16 of the air conditioner is turned off, the energizing side and the contact side of the control device 14 and the electromagnetic relay are de-energized, the electromagnetic clutch 6 is also disconnected, and the compressor 1 is stopped. At this time, the pulse generator 13 generates a predetermined number of pulses similar to the initial state at the time of starting the engine after the connection with the control device 14 is cut off.
Return 5 to the minimum capacity position. Therefore, even when the switch 16 of the air conditioner is turned on again, the compressor 1 can be started with the minimum capacity.

[0028]

As described above, according to the first and second aspects of the present invention, when the compressor is started, the discharge capacity of the compressor is always the minimum capacity, so that the starting torque of the compressor is reduced. Thus, the load on the engine is reduced. In addition, since the compressor continues to operate with the minimum capacity for a predetermined time from the start, the liquid refrigerant that has accumulated in the compressor and in the compressor suction pipe and the like is slowly discharged, and liquid compression is prevented. According to the second aspect of the present invention, the compressor is driven by driving the driving means in response to a signal from a detecting means for detecting an evaporator surface temperature or an evaporator outlet air temperature which changes according to an air conditioning load. , The compressor displacement can be controlled according to the air conditioning load in the vehicle, and the comfort in the vehicle can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a control system for a vehicle air conditioner according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a compressor having a scroll-type bypass-unloading-type capacity control mechanism according to the embodiment of the present invention.

FIG. 3 is an enlarged explanatory view of a stepping motor and a bypass piston in the compressor of FIG. 2;

FIG. 4 is a schematic diagram of a control system for a conventional vehicle air conditioner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor with capacity control 5 Evaporator 6 Electromagnetic clutch 9 Running engine 13 Pulse generator 14 Control device 15 Electromagnetic relay 16 Air-conditioner start / stop switch 19 Temperature sensor 65 Orbiting scroll 66 Fixed scroll 70, 73 Bypass hole 74 Bypass cylinder 75 Bypass piston 76 Stepper motor

Claims (2)

[Claims] 1. A compressor that receives a driving force of an engine for driving a vehicle via an electromagnetic clutch, a displacement control mechanism that is built in the compressor and controls a discharge displacement of the compressor, and drives the displacement control mechanism. A vehicle air conditioner having a driving unit, wherein when the electromagnetic clutch is connected, the discharge capacity of the compressor is set to a minimum capacity for a predetermined time after the connection of the electromagnetic clutch, and the driving unit is driven when the electromagnetic clutch is disconnected. An air conditioner for a vehicle, wherein the discharge capacity of the compressor is reduced to a minimum capacity. 2. During a steady operation, the driving means is driven by a signal from a sensing means for sensing a temperature of an evaporator surface, an evaporator outlet air, etc., corresponding to an air conditioning load of the air conditioner, thereby driving the compressor. The vehicle air conditioner according to claim 1, wherein the discharge capacity is controlled.